Sample records for accurate boussinesq-type models

  1. A Boussinesq-scaled, pressure-Poisson water wave model

    NASA Astrophysics Data System (ADS)

    Donahue, Aaron S.; Zhang, Yao; Kennedy, Andrew B.; Westerink, Joannes J.; Panda, Nishant; Dawson, Clint

    2015-02-01

    Through the use of Boussinesq scaling we develop and test a model for resolving non-hydrostatic pressure profiles in nonlinear wave systems over varying bathymetry. A Green-Nagdhi type polynomial expansion is used to resolve the pressure profile along the vertical axis, this is then inserted into the pressure-Poisson equation, retaining terms up to a prescribed order and solved using a weighted residual approach. The model shows rapid convergence properties with increasing order of polynomial expansion which can be greatly improved through the application of asymptotic rearrangement. Models of Boussinesq scaling of the fully nonlinear O (μ2) and weakly nonlinear O (μN) are presented, the analytical and numerical properties of O (μ2) and O (μ4) models are discussed. Optimal basis functions in the Green-Nagdhi expansion are determined through manipulation of the free-parameters which arise due to the Boussinesq scaling. The optimal O (μ2) model has dispersion accuracy equivalent to a Padé [2,2] approximation with one extra free-parameter. The optimal O (μ4) model obtains dispersion accuracy equivalent to a Padé [4,4] approximation with two free-parameters which can be used to optimize shoaling or nonlinear properties. In comparison to experimental results the O (μ4) model shows excellent agreement to experimental data.

  2. On wave breaking for Boussinesq-type models

    NASA Astrophysics Data System (ADS)

    Kazolea, M.; Ricchiuto, M.

    2018-03-01

    We consider the issue of wave breaking closure for Boussinesq type models, and attempt at providing some more understanding of the sensitivity of some closure approaches to the numerical set-up, and in particular to mesh size. For relatively classical choices of weakly dispersive propagation models, we compare two closure strategies. The first is the hybrid method consisting in suppressing the dispersive terms in breaking regions, as initially suggested by Tonelli and Petti in 2009. The second is an eddy viscosity approach based on the solution of a a turbulent kinetic energy. The formulation follows early work by O. Nwogu in the 90's, and some more recent developments by Zhang and co-workers (Ocean Mod. 2014), adapting it to be consistent with the wave breaking detection used here. We perform a study of the behaviour of the two closures for different mesh sizes, with attention to the possibility of obtaining grid independent results. Based on a classical shallow water theory, we also suggest some monitors to quantify the different contributions to the dissipation mechanism, differentiating those associated to the scheme from those of the partial differential equation. These quantities are used to analyze the dynamics of dissipation in some classical benchmarks, and its dependence on the mesh size. Our main results show that numerical dissipation contributes very little to the the results obtained when using eddy viscosity method. This closure shows little sensitivity to the grid, and may lend itself to the development and use of non-dissipative/energy conserving numerical methods. The opposite is observed for the hybrid approach, for which numerical dissipation plays a key role, and unfortunately is sensitive to the size of the mesh. In particular, when working, the two approaches investigated provide results which are in the same ball range and which agree with what is usually reported in literature. With the hybrid method, however, the inception of instabilities

  3. A reasoned overview on Boussinesq-type models: the interplay between physics, mathematics and numerics.

    PubMed

    Brocchini, Maurizio

    2013-12-08

    This paper, which is largely the fruit of an invited talk on the topic at the latest International Conference on Coastal Engineering, describes the state of the art of modelling by means of Boussinesq-type models (BTMs). Motivations for using BTMs as well as their fundamentals are illustrated, with special attention to the interplay between the physics to be described, the chosen model equations and the numerics in use. The perspective of the analysis is that of a physicist/engineer rather than of an applied mathematician. The chronological progress of the currently available BTMs from the pioneering models of the late 1960s is given. The main applications of BTMs are illustrated, with reference to specific models and methods. The evolution in time of the numerical methods used to solve BTMs (e.g. finite differences, finite elements, finite volumes) is described, with specific focus on finite volumes. Finally, an overview of the most important BTMs currently available is presented, as well as some indications on improvements required and fields of applications that call for attention.

  4. A reasoned overview on Boussinesq-type models: the interplay between physics, mathematics and numerics

    PubMed Central

    Brocchini, Maurizio

    2013-01-01

    This paper, which is largely the fruit of an invited talk on the topic at the latest International Conference on Coastal Engineering, describes the state of the art of modelling by means of Boussinesq-type models (BTMs). Motivations for using BTMs as well as their fundamentals are illustrated, with special attention to the interplay between the physics to be described, the chosen model equations and the numerics in use. The perspective of the analysis is that of a physicist/engineer rather than of an applied mathematician. The chronological progress of the currently available BTMs from the pioneering models of the late 1960s is given. The main applications of BTMs are illustrated, with reference to specific models and methods. The evolution in time of the numerical methods used to solve BTMs (e.g. finite differences, finite elements, finite volumes) is described, with specific focus on finite volumes. Finally, an overview of the most important BTMs currently available is presented, as well as some indications on improvements required and fields of applications that call for attention. PMID:24353475

  5. Mechanical Balance Laws for Boussinesq Models of Surface Water Waves

    NASA Astrophysics Data System (ADS)

    Ali, Alfatih; Kalisch, Henrik

    2012-06-01

    Depth-integrated long-wave models, such as the shallow-water and Boussinesq equations, are standard fare in the study of small amplitude surface waves in shallow water. While the shallow-water theory features conservation of mass, momentum and energy for smooth solutions, mechanical balance equations are not widely used in Boussinesq scaling, and it appears that the expressions for many of these quantities are not known. This work presents a systematic derivation of mass, momentum and energy densities and fluxes associated with a general family of Boussinesq systems. The derivation is based on a reconstruction of the velocity field and the pressure in the fluid column below the free surface, and the derivation of differential balance equations which are of the same asymptotic validity as the evolution equations. It is shown that all these mechanical quantities can be expressed in terms of the principal dependent variables of the Boussinesq system: the surface excursion η and the horizontal velocity w at a given level in the fluid.

  6. Influence of Boussinesq coefficient on depth-averaged modelling of rapid flows

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Liang, Dongfang; Xiao, Yang

    2018-04-01

    The traditional Alternating Direction Implicit (ADI) scheme has been proven to be incapable of modelling trans-critical flows. Its inherent lack of shock-capturing capability often results in spurious oscillations and computational instabilities. However, the ADI scheme is still widely adopted in flood modelling software, and various special treatments have been designed to stabilise the computation. Modification of the Boussinesq coefficient to adjust the amount of fluid inertia is a numerical treatment that allows the ADI scheme to be applicable to rapid flows. This study comprehensively examines the impact of this numerical treatment over a range of flow conditions. A shock-capturing TVD-MacCormack model is used to provide reference results. For unsteady flows over a frictionless bed, such as idealised dam-break floods, the results suggest that an increase in the value of the Boussinesq coefficient reduces the amplitude of the spurious oscillations. The opposite is observed for steady rapid flows over a frictional bed. Finally, a two-dimensional urban flooding phenomenon is presented, involving unsteady flow over a frictional bed. The results show that increasing the value of the Boussinesq coefficient can significantly reduce the numerical oscillations and reduce the predicted area of inundation. In order to stabilise the ADI computations, the Boussinesq coefficient could be judiciously raised or lowered depending on whether the rapid flow is steady or unsteady and whether the bed is frictional or frictionless. An increase in the Boussinesq coefficient generally leads to overprediction of the propagating speed of the flood wave over a frictionless bed, but the opposite is true when bed friction is significant.

  7. Parallelization of elliptic solver for solving 1D Boussinesq model

    NASA Astrophysics Data System (ADS)

    Tarwidi, D.; Adytia, D.

    2018-03-01

    In this paper, a parallel implementation of an elliptic solver in solving 1D Boussinesq model is presented. Numerical solution of Boussinesq model is obtained by implementing a staggered grid scheme to continuity, momentum, and elliptic equation of Boussinesq model. Tridiagonal system emerging from numerical scheme of elliptic equation is solved by cyclic reduction algorithm. The parallel implementation of cyclic reduction is executed on multicore processors with shared memory architectures using OpenMP. To measure the performance of parallel program, large number of grids is varied from 28 to 214. Two test cases of numerical experiment, i.e. propagation of solitary and standing wave, are proposed to evaluate the parallel program. The numerical results are verified with analytical solution of solitary and standing wave. The best speedup of solitary and standing wave test cases is about 2.07 with 214 of grids and 1.86 with 213 of grids, respectively, which are executed by using 8 threads. Moreover, the best efficiency of parallel program is 76.2% and 73.5% for solitary and standing wave test cases, respectively.

  8. On the local well-posedness and a Prodi-Serrin-type regularity criterion of the three-dimensional MHD-Boussinesq system without thermal diffusion

    NASA Astrophysics Data System (ADS)

    Larios, Adam; Pei, Yuan

    2017-07-01

    We prove a Prodi-Serrin-type global regularity condition for the three-dimensional Magnetohydrodynamic-Boussinesq system (3D MHD-Boussinesq) without thermal diffusion, in terms of only two velocity and two magnetic components. To the best of our knowledge, this is the first Prodi-Serrin-type criterion for such a 3D hydrodynamic system which is not fully dissipative, and indicates that such an approach may be successful on other systems. In addition, we provide a constructive proof of the local well-posedness of solutions to the fully dissipative 3D MHD-Boussinesq system, and also the fully inviscid, irresistive, non-diffusive MHD-Boussinesq equations. We note that, as a special case, these results include the 3D non-diffusive Boussinesq system and the 3D MHD equations. Moreover, they can be extended without difficulty to include the case of a Coriolis rotational term.

  9. Thermal diffusion of Boussinesq solitons.

    PubMed

    Arévalo, Edward; Mertens, Franz G

    2007-10-01

    We consider the problem of the soliton dynamics in the presence of an external noisy force for the Boussinesq type equations. A set of ordinary differential equations (ODEs) of the relevant coordinates of the system is derived. We show that for the improved Boussinesq (IBq) equation the set of ODEs has limiting cases leading to a set of ODEs which can be directly derived either from the ill-posed Boussinesq equation or from the Korteweg-de Vries (KdV) equation. The case of a soliton propagating in the presence of damping and thermal noise is considered for the IBq equation. A good agreement between theory and simulations is observed showing the strong robustness of these excitations. The results obtained here generalize previous results obtained in the frame of the KdV equation for lattice solitons in the monatomic chain of atoms.

  10. Similarity solution of the Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Lockington, D. A.; Parlange, J.-Y.; Parlange, M. B.; Selker, J.

    Similarity transforms of the Boussinesq equation in a semi-infinite medium are available when the boundary conditions are a power of time. The Boussinesq equation is reduced from a partial differential equation to a boundary-value problem. Chen et al. [Trans Porous Media 1995;18:15-36] use a hodograph method to derive an integral equation formulation of the new differential equation which they solve by numerical iteration. In the present paper, the convergence of their scheme is improved such that numerical iteration can be avoided for all practical purposes. However, a simpler analytical approach is also presented which is based on Shampine's transformation of the boundary value problem to an initial value problem. This analytical approximation is remarkably simple and yet more accurate than the analytical hodograph approximations.

  11. Recurrence in truncated Boussinesq models for nonlinear waves in shallow water

    NASA Technical Reports Server (NTRS)

    Elgar, Steve; Freilich, M. H.; Guza, R. T.

    1990-01-01

    The rapid spatial recurrence of weakly nonlinear and weakly dispersive progressive shallow-water waves is examined using a numerical integration technique on the discretized and truncated form of the Boussinesq equations. This study primarily examines recurrence in wave fields with Ursell number O(1) and characterizes the sensitivity of recurrence to initial spectral shape and number of allowed frequency modes. It is shown that the rapid spatial recurrence is not an inherent property of the considered Boussinesq systems for evolution distances of 10-50 wavelengths. The main result of the study is that highly truncated Boussinesq models of resonant shallow-water ocean surface gravity waves predict rapid multiple recurrence cycles, but that this is an artifact dependent on the number of allowed modes. For initial conditions consisting of essentially all energy concentrated in a single mode, damping of the recurrence cycles increases as the number of low-power background modes increases. When more than 32 modes are allowed, the recurrence behavior is relatively insensitive to the number of allowed modes.

  12. NonBoussinesq effects on vorticity and kinetic energy production

    NASA Astrophysics Data System (ADS)

    Ravichandran, S.; Dixit, Harish; Govindarajan, Rama

    2015-11-01

    The Boussinesq approximation, commonly employed in weakly compressible or incompressible flows, neglects changes in inertia due to changes in the density. However, the nonBoussinesq terms can lead to a kind of centrifugal instability for small but sharp density variations, and therefore cannot be neglected under such circumstances (see, e.g., type="smallcap">DIXIT & GOVINDARAJAN, JFM , 2010, 415). Here, we study the evolution of a light-cored Gaussian vortex and find that the nonBoussinesq terms can lead to significant changes in how vortices evolve. The problem is governed by three nondimensional numbers--Reynolds number (i.e. viscosity), Atwood number, and a ratio of gravitational and centrifugal Froude numbers. We find that the production of kinetic energy and vorticity in a light-cored Gaussian vortex are affected significantly by the nonBoussinesq terms, and varies non-monotonically with the parameters of the problem. In general, these nonBoussinesq effects depend both on the strength of gravity and on the Reynolds number associated with the initial vortex.

  13. Simulating run-up on steep slopes with operational Boussinesq models; capabilities, spurious effects and instabilities

    NASA Astrophysics Data System (ADS)

    Løvholt, F.; Lynett, P.; Pedersen, G.

    2013-06-01

    Tsunamis induced by rock slides plunging into fjords constitute a severe threat to local coastal communities. The rock slide impact may give rise to highly non-linear waves in the near field, and because the wave lengths are relatively short, frequency dispersion comes into play. Fjord systems are rugged with steep slopes, and modeling non-linear dispersive waves in this environment with simultaneous run-up is demanding. We have run an operational Boussinesq-type TVD (total variation diminishing) model using different run-up formulations. Two different tests are considered, inundation on steep slopes and propagation in a trapezoidal channel. In addition, a set of Lagrangian models serves as reference models. Demanding test cases with solitary waves with amplitudes ranging from 0.1 to 0.5 were applied, and slopes were ranging from 10 to 50°. Different run-up formulations yielded clearly different accuracy and stability, and only some provided similar accuracy as the reference models. The test cases revealed that the model was prone to instabilities for large non-linearity and fine resolution. Some of the instabilities were linked with false breaking during the first positive inundation, which was not observed for the reference models. None of the models were able to handle the bore forming during drawdown, however. The instabilities are linked to short-crested undulations on the grid scale, and appear on fine resolution during inundation. As a consequence, convergence was not always obtained. It is reason to believe that the instability may be a general problem for Boussinesq models in fjords.

  14. Mechanism of nonlinear flow pattern selection in moderately non-Boussinesq mixed convection.

    PubMed

    Suslov, Sergey A

    2010-02-01

    Nonlinear (non-Boussinesq) variations in fluid's density, viscosity, and thermal conductivity caused by a large temperature gradient in a flow domain lead to a wide variety of instability phenomena in mixed convection channel flow of a simple gas such as air. It is known that in strongly nonisothermal flows, the instabilities and the resulting flow patterns are caused by competing buoyancy and shear effects [see S. A. Suslov and S. Paolucci, J. Fluid Mech. 302, 91 (1995)]. However, as is the case in the Boussinesq limit of small temperature gradients, in moderately non-Boussinesq regimes, only a shear instability mechanism is active. Yet in contrast to Boussinesq flows, multiple instability modes are still detected. By reducing the system of full governing Navier-Stokes equations to a dynamical system of coupled Landau-type disturbance amplitude equations we compute a comprehensive parametric map of various shear-driven instabilities observed in a representative moderately non-Boussinesq regime. Subsequently, we analyze nonlinear interaction of unstable modes and reveal physical reasons for their appearance.

  15. Some Boussinesq Equations with Saturation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Christou, M. A.

    2010-11-25

    We investigate numerically some Boussinesq type equations with square or cubic and saturated nonlinearity. We examine the propagation, interaction and overtake interaction of soliton solutions. Moreover, we examine the effect of the saturation term on the solution and compare it with the classical case of the square or cubic nonlinearity without saturation. We calculate numerically the phase shift experienced by the solitons upon collision and conclude the impact of saturation.

  16. Joseph Boussinesq et son approximation : un aperçu actuel

    NASA Astrophysics Data System (ADS)

    Zeytounian, Radyadour Kh.

    2003-08-01

    A hundred years ago, in his 1903 volume II of the monograph devoted to 'Théorie Analytique de la Chaleur', Joseph Valentin Boussinesq observes that: "The v ariations of density can be ignored except were they are multiplied by the acceleration of gravity in equation of motion for the vertical component of the velocity vector." A spectacular consequence of this Boussinesq observation (called, in 1916, by Rayleigh, the 'Boussinesq approximation') is the possibility to work with a quasi-incompressible system of coupled dynamic, (Navier) and thermal (Fourier) equations where buoyancy is the main driving force. After a few words on the life of Boussinesq and on his observation, the applicability of this approximation is briefly discussed for various thermal, geophysical, astrophysical and magnetohydrodynamic problems in the framework of 'Boussinesquian fluid dynamics'. An important part of our contemporary view is devoted to a logical (100 years later) justification of this Boussinesq approximation for a perfect gas and an ideal liquid in the framework of an asymptotic modelling of the full fluid dynamics (Euler and Navier-Stokes-Fourier) equations with especially careful attention given to the validity of this approximation. To cite this article: R.Kh. Zeytounian, C. R. Mecanique 331 (2003).

  17. Comparison of internal wave properties calculated by Boussinesq equations with/without rigid-lid assumption

    NASA Astrophysics Data System (ADS)

    Liu, C. M.

    2017-12-01

    Wave properties predicted by the rigid-lid and the free-surface Boussinesq equations for a two-fluid system are theoretically calculated and compared in this study. Boussinesq model is generally applied to numerically simulate surface waves in coastal regions to provide credible information for disaster prevention and breaker design. As for internal waves, Liu et al. (2008) and Liu (2016) respectively derived a free-surface model and a rigid-lid Boussinesq models for a two-fluid system. The former and the latter models respectively contain four and three key variables which may result in different results and efficiency while simulating. Therefore, present study shows the results theoretically measured by these two models to provide more detailed observation and useful information for motions of internal waves.

  18. Time-splitting combined with exponential wave integrator fourier pseudospectral method for Schrödinger-Boussinesq system

    NASA Astrophysics Data System (ADS)

    Liao, Feng; Zhang, Luming; Wang, Shanshan

    2018-02-01

    In this article, we formulate an efficient and accurate numerical method for approximations of the coupled Schrödinger-Boussinesq (SBq) system. The main features of our method are based on: (i) the applications of a time-splitting Fourier spectral method for Schrödinger-like equation in SBq system, (ii) the utilizations of exponential wave integrator Fourier pseudospectral for spatial derivatives in the Boussinesq-like equation. The scheme is fully explicit and efficient due to fast Fourier transform. The numerical examples are presented to show the efficiency and accuracy of our method.

  19. The Boussinesq Debate: Reversibility, Instability, and Free Will.

    PubMed

    Michael Mueller, Thomas

    2015-12-01

    In 1877, a young mathematician named Joseph Boussinesq presented a mémoire to the Académie des sciences which demonstrated that some differential equations may have more than one solution. Boussinesq linked this fact to indeterminism and to a possible solution to the free will versus determinism debate. Boussinesq's main interest was to reconcile his philosophical and religious views with science by showing that matter and motion do not suffice to explain all there is in the world. His argument received mixed criticism that addressed both his philosophical views and the scientific content of his work, pointing to the physical "realisticness" of multiple solutions. While Boussinesq proved to be able to face the philosophical criticism, the scientific objections became a serious problem, thus slowly moving the focus of the debate from the philosophical plane to the scientific one. This change of perspective implied a wide discussion on topics such as instability, the sensitivity to initial conditions, and the conservation of energy. The Boussinesq debate is an example of a philosophically motivated debate that transforms into a scientific one, an example of the influence of philosophy on the development of science.

  20. A moist Boussinesq shallow water equations set for testing atmospheric models

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zerroukat, M., E-mail: mohamed.zerroukat@metoffice.gov.uk; Allen, T.

    The shallow water equations have long been used as an initial test for numerical methods applied to atmospheric models with the test suite of Williamson et al. being used extensively for validating new schemes and assessing their accuracy. However the lack of physics forcing within this simplified framework often requires numerical techniques to be reworked when applied to fully three dimensional models. In this paper a novel two-dimensional shallow water equations system that retains moist processes is derived. This system is derived from three-dimensional Boussinesq approximation of the hydrostatic Euler equations where, unlike the classical shallow water set, we allowmore » the density to vary slightly with temperature. This results in extra (or buoyancy) terms for the momentum equations, through which a two-way moist-physics dynamics feedback is achieved. The temperature and moisture variables are advected as separate tracers with sources that interact with the mean-flow through a simplified yet realistic bulk moist-thermodynamic phase-change model. This moist shallow water system provides a unique tool to assess the usually complex and highly non-linear dynamics–physics interactions in atmospheric models in a simple yet realistic way. The full non-linear shallow water equations are solved numerically on several case studies and the results suggest quite realistic interaction between the dynamics and physics and in particular the generation of cloud and rain. - Highlights: • Novel shallow water equations which retains moist processes are derived from the three-dimensional hydrostatic Boussinesq equations. • The new shallow water set can be seen as a more general one, where the classical equations are a special case of these equations. • This moist shallow water system naturally allows a feedback mechanism from the moist physics increments to the momentum via buoyancy. • Like full models, temperature and moistures are advected as tracers that

  1. New Similarity Reductions and Compacton Solutions for Boussinesq-Like Equations with Fully Nonlinear Dispersion

    NASA Astrophysics Data System (ADS)

    Yan, Zhen-Ya

    2001-10-01

    In this paper, similarity reductions of Boussinesq-like equations with nonlinear dispersion (simply called B(m,n) equations) utt=(u^n)xx+(u^m)xxxx, which is a generalized model of Boussinesq equation utt=(u^2)xx+uxxxx and modified Bousinesq equation utt=(u^3)xx+uxxxx, are considered by using the direct reduction method. As a result, several new types of similarity reductions are found. Based on the reduction equations and some simple transformations, we obtain the solitary wave solutions and compacton solutions (which are solitary waves with the property that after colliding with other compacton solutions, they re-emerge with the same coherent shape) of B(1,n) equations and B(m,m) equations, respectively. The project supported by National Key Basic Research Development Project Program of China under Grant No. G1998030600 and Doctoral Foundation of China under Grant No. 98014119

  2. Blowup with vorticity control for a 2D model of the Boussinesq equations

    NASA Astrophysics Data System (ADS)

    Hoang, V.; Orcan-Ekmekci, B.; Radosz, M.; Yang, H.

    2018-06-01

    We propose a system of equations with nonlocal flux in two space dimensions which is closely modeled after the 2D Boussinesq equations in a hyperbolic flow scenario. Our equations involve a vorticity stretching term and a non-local Biot-Savart law and provide insight into the underlying intrinsic mechanisms of singularity formation. We prove stable, controlled finite time blowup involving upper and lower bounds on the vorticity up to the time of blowup for a wide class of initial data.

  3. A Class of Exact Solutions of the Boussinesq Equation for Horizontal and Sloping Aquifers

    NASA Astrophysics Data System (ADS)

    Bartlett, M. S.; Porporato, A.

    2018-02-01

    The nonlinear equation of Boussinesq (1877) is a foundational approach for studying groundwater flow through an unconfined aquifer, but solving the full nonlinear version of the Boussinesq equation remains a challenge. Here, we present an exact solution to the full nonlinear Boussinesq equation that not only applies to sloping aquifers but also accounts for source and sink terms such as bedrock seepage, an often significant flux in headwater catchments. This new solution captures the hysteretic relationship (a loop rating curve) between the groundwater flow rate and the water table height, which may be used to provide a more realistic representation of streamflow and groundwater dynamics in hillslopes. In addition, the solution provides an expression where the flow recession varies based on hillslope parameters such as bedrock slope, bedrock seepage, aquifer recharge, plant transpiration, and other factors that vary across landscape types.

  4. Non-Boussinesq Dissolution-Driven Convection in Porous Media

    NASA Astrophysics Data System (ADS)

    Amooie, M. A.; Soltanian, M. R.; Moortgat, J.

    2017-12-01

    Geological carbon dioxide (CO2) sequestration in deep saline aquifers has been increasingly recognized as a feasible technology to stabilize the atmospheric carbon concentrations and subsequently mitigate the global warming. Solubility trapping is one of the most effective storage mechanisms, which is associated initially with diffusion-driven slow dissolution of gaseous CO2 into the aqueous phase, followed by density-driven convective mixing of CO2 throughout the aquifer. The convection includes both diffusion and fast advective transport of the dissolved CO2. We study the fluid dynamics of CO2 convection in the underlying single aqueous-phase region. Two modeling approaches are employed to define the system: (i) a constant-concentration condition for CO2 in aqueous phase at the top boundary, and (ii) a sufficiently low, constant injection-rate for CO2 from top boundary. The latter allows for thermodynamically consistent evolution of the CO2 composition and the aqueous phase density against the rate at which the dissolved CO2 convects. Here we accurately model the full nonlinear phase behavior of brine-CO2 mixture in a confined domain altered by dissolution and compressibility, while relaxing the common Boussinesq approximation. We discover new flow regimes and present quantitative scaling relations for global characters of spreading, mixing, and dissolution flux in two- and three-dimensional media for the both model types. We then revisit the universal Sherwood-Rayleigh scaling that is under debate for porous media convective flows. Our findings confirm the sublinear scaling for the constant-concentration case, while reconciling the classical linear scaling for the constant-injection model problem. The results provide a detailed perspective into how the available modeling strategies affect the prediction ability for the total amount of CO2 dissolved in the long term within saline aquifers of different permeabilities.

  5. Inertial Range Dynamics in Boussinesq Turbulence

    NASA Technical Reports Server (NTRS)

    Rubinstein, Robert

    1996-01-01

    L'vov and Falkovich have shown that the dimensionally possible inertial range scaling laws for Boussinesq turbulence, Kolmogorov and Bolgiano scaling, describe steady states with constant flux of kinetic energy and of entropy respectively. These scaling laws are treated as similarity solutions of the direct interaction approximation for Boussinesq turbulence. The Kolmogorov scaling solution corresponds to a weak perturbation by gravity of a state in which the temperature is a passive scalar but in which a source of temperature fluctuations exists. Using standard inertial range balances, the renormalized viscosity and conductivity, turbulent Prandtl number, and spectral scaling law constants are computed for Bolgiano scaling.

  6. Numerical study of the small scale structures in Boussinesq convection

    NASA Technical Reports Server (NTRS)

    Weinan, E.; Shu, Chi-Wang

    1992-01-01

    Two-dimensional Boussinesq convection is studied numerically using two different methods: a filtered pseudospectral method and a high order accurate Essentially Nonoscillatory (ENO) scheme. The issue whether finite time singularity occurs for initially smooth flows is investigated. The numerical results suggest that the collapse of the bubble cap is unlikely to occur in resolved calculations. The strain rate corresponding to the intensification of the density gradient across the front saturates at the bubble cap. We also found that the cascade of energy to small scales is dominated by the formulation of thin and sharp fronts across which density jumps.

  7. Optimal Transport, Convection, Magnetic Relaxation and Generalized Boussinesq Equations

    NASA Astrophysics Data System (ADS)

    Brenier, Yann

    2009-10-01

    We establish a connection between optimal transport theory (see Villani in Topics in optimal transportation. Graduate studies in mathematics, vol. 58, AMS, Providence, 2003, for instance) and classical convection theory for geophysical flows (Pedlosky, in Geophysical fluid dynamics, Springer, New York, 1979). Our starting point is the model designed few years ago by Angenent, Haker, and Tannenbaum (SIAM J. Math. Anal. 35:61-97, 2003) to solve some optimal transport problems. This model can be seen as a generalization of the Darcy-Boussinesq equations, which is a degenerate version of the Navier-Stokes-Boussinesq (NSB) equations. In a unified framework, we relate different variants of the NSB equations (in particular what we call the generalized hydrostatic-Boussinesq equations) to various models involving optimal transport (and the related Monge-Ampère equation, Brenier in Commun. Pure Appl. Math. 64:375-417, 1991; Caffarelli in Commun. Pure Appl. Math. 45:1141-1151, 1992). This includes the 2D semi-geostrophic equations (Hoskins in Annual review of fluid mechanics, vol. 14, pp. 131-151, Palo Alto, 1982; Cullen et al. in SIAM J. Appl. Math. 51:20-31, 1991, Arch. Ration. Mech. Anal. 185:341-363, 2007; Benamou and Brenier in SIAM J. Appl. Math. 58:1450-1461, 1998; Loeper in SIAM J. Math. Anal. 38:795-823, 2006) and some fully nonlinear versions of the so-called high-field limit of the Vlasov-Poisson system (Nieto et al. in Arch. Ration. Mech. Anal. 158:29-59, 2001) and of the Keller-Segel for Chemotaxis (Keller and Segel in J. Theor. Biol. 30:225-234, 1971; Jäger and Luckhaus in Trans. Am. Math. Soc. 329:819-824, 1992; Chalub et al. in Mon. Math. 142:123-141, 2004). Mathematically speaking, we establish some existence theorems for local smooth, global smooth or global weak solutions of the different models. We also justify that the inertia terms can be rigorously neglected under appropriate scaling assumptions in the generalized Navier-Stokes-Boussinesq equations

  8. The formation of shocks and fundamental solution of a fourth-order quasilinear Boussinesq-type equation

    NASA Astrophysics Data System (ADS)

    Galaktionov, Victor A.

    2009-02-01

    As a basic higher-order model, the fourth-order Boussinesq-type quasilinear wave equation (the QWE-4) \\[ \\begin{equation*}\\fl u_{tt} = -(|u|^n u)_{xxxx} \\tqs in\\ \\mathbb{R} \\times \\mathbb{R}_+, \\quad with\\ exponent\\ n > 0,\\end{equation*} \\] is considered. Self-similar blow-up solutions \\[ \\begin{eqnarray*}\\tqs\\tqs u_-(x,t)=g(z), \\quad\\, z=\\frac x{\\sqrt{T-t}},\\\\ where\\ g\\ solved\\ the\\ ODE\\ \\frac 14 g'' z^2 + \\frac 34 g'z = -(|g|^n g)^{(4)},\\end{eqnarray*} \\] are shown to exist that generate as t → T- discontinuous shock waves. The QWE-4 is also shown to admit a smooth (for t > 0) global 'fundamental solution' \\[ \\begin{eqnarray*}\\fl b_n(x,t)= t^{\\frac{2}{n+4}} F_n(y),\\ y = x/t^{\\frac{n+2}{n+4}},\\ such\\ that\\ b_{n}(x,0)= 0,\\ b_{nt}(x,0)= {\\delta}(x),\\end{eqnarray*} \\] i.e. having a measure as initial data. A 'homotopic' limit n → 0 is used to get b_0(x,t)= \\sqrt t \\, F_0(x/\\sqrt t) being the classic fundamental solution of the 1D linear beam equation \\[ \\begin{equation*}u_{tt} = -u_{xxxx} \\tqs in\\ \\mathbb{R} \\times \\mathbb{R}_+.\\end{equation*} \\

  9. Systematic investigation of non-Boussinesq effects in variable-density groundwater flow simulations.

    PubMed

    Guevara Morel, Carlos R; van Reeuwijk, Maarten; Graf, Thomas

    2015-12-01

    The validity of three mathematical models describing variable-density groundwater flow is systematically evaluated: (i) a model which invokes the Oberbeck-Boussinesq approximation (OB approximation), (ii) a model of intermediate complexity (NOB1) and (iii) a model which solves the full set of equations (NOB2). The NOB1 and NOB2 descriptions have been added to the HydroGeoSphere (HGS) model, which originally contained an implementation of the OB description. We define the Boussinesq parameter ερ=βω Δω where βω is the solutal expansivity and Δω is the characteristic difference in solute mass fraction. The Boussinesq parameter ερ is used to systematically investigate three flow scenarios covering a range of free and mixed convection problems: 1) the low Rayleigh number Elder problem (Van Reeuwijk et al., 2009), 2) a convective fingering problem (Xie et al., 2011) and 3) a mixed convective problem (Schincariol et al., 1994). Results indicate that small density differences (ερ≤ 0.05) produce no apparent changes in the total solute mass in the system, plume penetration depth, center of mass and mass flux independent of the mathematical model used. Deviations between OB, NOB1 and NOB2 occur for large density differences (ερ>0.12), where lower description levels will underestimate the vertical plume position and overestimate mass flux. Based on the cases considered here, we suggest the following guidelines for saline convection: the OB approximation is valid for cases with ερ<0.05, and the full NOB set of equations needs to be used for cases with ερ>0.10. Whether NOB effects are important in the intermediate region differ from case to case. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Higher spin Chern-Simons theory and the super Boussinesq hierarchy

    NASA Astrophysics Data System (ADS)

    Gutperle, Michael; Li, Yi

    2018-05-01

    In this paper, we construct a map between a solution of supersymmetric Chern-Simons higher spin gravity based on the superalgebra sl(3|2) with Lifshitz scaling and the N = 2 super Boussinesq hierarchy. We show that under this map the time evolution equations of both theories coincide. In addition, we identify the Poisson structure of the Chern-Simons theory induced by gauge transformation with the second Hamiltonian structure of the super Boussinesq hierarchy.

  11. A Non-Incompressible Non-Boussinesq (NINB) framework for studying atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    Yan, C.; Archer, C. L.; Xie, S.; Ghaisas, N.

    2015-12-01

    The incompressible assumption is widely used for studying the turbulent atmospheric boundary layer (ABL) and is generally accepted when the Mach number < ~0.3 (velocity < ~100 m/s). Since the tips of modern wind turbine blades can reach and exceed this threshold, neglecting air compressibility will introduce errors. In addition, if air incompressibility does not hold, then the Boussinesq approximation, by which air density is treated as a constant except in the gravity term of the Navier-Stokes equation, is also invalidated. Here, we propose a new theoretical framework, called NINB for Non-Incompressible Non-Boussinesq, in which air is not considered incompressible and air density is treated as a non-turbulent 4D variable. First, the NINB mass, momentum, and energy conservation equations are developed using Reynolds averaging. Second, numerical simulations of the NINB equations, coupled with a k-epsilon turbulence model, are performed with the finite-volume method. Wind turbines are modeled with the actuator-line model using SOWFA (Software for Offshore/onshore Wind Farm Applications). Third, NINB results are compared with the traditional incompressible buoyant simulations performed by SOWFA with the same set up. The results show differences between NINB and traditional simulations in the neutral atmosphere with a wind turbine. The largest differences in wind speed (up to 1 m/s), turbulent kinetic energy (~10%), dissipation rate (~5%), and shear stress (~10%) occur near the turbine tip region. The power generation differences are 5-15% (depending on setup). These preliminary results suggest that compressibility effects are non-negligible around wind turbines and should be taken into account when forecasting wind power. Since only a few extra terms are introduced, the NINB framework may be an alternative to the traditional incompressible Boussinesq framework for studying the turbulent ABL in general (i.e., without turbines) in the absence of shock waves.

  12. Rayleigh-Bénard-Marangoni convection in a weakly non-Boussinesq fluid layer with a deformable surface

    NASA Astrophysics Data System (ADS)

    Lyubimov, D. V.; Lyubimova, T. P.; Lobov, N. I.; Alexander, J. I. D.

    2018-02-01

    The influence of surface deformations on the Rayleigh-Bénard-Marangoni instability of a uniform layer of a non-Boussinesq fluid heated from below is investigated. In particular, the stability of the conductive state of a horizontal fluid layer with a deformable surface, a flat isothermal rigid lower boundary, and a convective heat transfer condition at the upper free surface is considered. The fluid is assumed to be isothermally incompressible. In contrast to the Boussinesq approximation, density variations are accounted for in the continuity equation and in the buoyancy and inertial terms of the momentum equations. Two different types of temperature dependence of the density are considered: linear and exponential. The longwave instability is studied analytically, and instability to perturbations with finite wavenumber is examined numerically. It is found that there is a decrease in stability of the system with respect to the onset of longwave Marangoni convection. This result could not be obtained within the framework of the conventional Boussinesq approximation. It is also shown that at Ma = 0 the critical Rayleigh number increases with Ga (the ratio of gravity to viscous forces or Galileo number). At some value of Ga, the Rayleigh-Bénard instability vanishes. This stabilization occurs for each of the density equations of state. At small values of Ga and when deformation of the free surface is important, it is shown that there are significant differences in stability behavior as compared to results obtained using the Boussinesq approximation.

  13. Efficient Non-Hydrostatic Modeling of Rotational, Turbulent, Dispersive, and Variable-Density Flows in the Vicinity of River Mouths and Inlets: Development and Field Support

    DTIC Science & Technology

    2013-09-30

    numerical efforts undertaken here implement established aspects of Boussinesq -type modeling, developed by the PI and other researchers. These aspects...the Boussinesq -type framework, and then implement in a numerical model. Once this comprehensive model is developed and tested against established...phenomena that might be observed at New River. WORK COMPLETED In FY13 we have continued the development of a Boussinesq -type formulation that

  14. On the Boussinesq-Burgers equations driven by dynamic boundary conditions

    NASA Astrophysics Data System (ADS)

    Zhu, Neng; Liu, Zhengrong; Zhao, Kun

    2018-02-01

    We study the qualitative behavior of the Boussinesq-Burgers equations on a finite interval subject to the Dirichlet type dynamic boundary conditions. Assuming H1 ×H2 initial data which are compatible with boundary conditions and utilizing energy methods, we show that under appropriate conditions on the dynamic boundary data, there exist unique global-in-time solutions to the initial-boundary value problem, and the solutions converge to the boundary data as time goes to infinity, regardless of the magnitude of the initial data.

  15. Evolution of initial discontinuities in the Riemann problem for the Kaup-Boussinesq equation with positive dispersion

    NASA Astrophysics Data System (ADS)

    Congy, T.; Ivanov, S. K.; Kamchatnov, A. M.; Pavloff, N.

    2017-08-01

    We consider the space-time evolution of initial discontinuities of depth and flow velocity for an integrable version of the shallow water Boussinesq system introduced by Kaup. We focus on a specific version of this "Kaup-Boussinesq model" for which a flat water surface is modulationally stable, we speak below of "positive dispersion" model. This model also appears as an approximation to the equations governing the dynamics of polarisation waves in two-component Bose-Einstein condensates. We describe its periodic solutions and the corresponding Whitham modulation equations. The self-similar, one-phase wave structures are composed of different building blocks, which are studied in detail. This makes it possible to establish a classification of all the possible wave configurations evolving from initial discontinuities. The analytic results are confirmed by numerical simulations.

  16. Evolution of initial discontinuities in the Riemann problem for the Kaup-Boussinesq equation with positive dispersion.

    PubMed

    Congy, T; Ivanov, S K; Kamchatnov, A M; Pavloff, N

    2017-08-01

    We consider the space-time evolution of initial discontinuities of depth and flow velocity for an integrable version of the shallow water Boussinesq system introduced by Kaup. We focus on a specific version of this "Kaup-Boussinesq model" for which a flat water surface is modulationally stable, we speak below of "positive dispersion" model. This model also appears as an approximation to the equations governing the dynamics of polarisation waves in two-component Bose-Einstein condensates. We describe its periodic solutions and the corresponding Whitham modulation equations. The self-similar, one-phase wave structures are composed of different building blocks, which are studied in detail. This makes it possible to establish a classification of all the possible wave configurations evolving from initial discontinuities. The analytic results are confirmed by numerical simulations.

  17. On the Effect of Feedback Control on Benard Convection in a Boussinesq Fluid

    NASA Technical Reports Server (NTRS)

    Shortis, Trudi A.; Hall, Philip

    1996-01-01

    The effect of nonlinear feedback control strategies on the platform of convection in a Boussinesq fluid heated from below is investigated. In the absence of the control, given that non-Boussinesq effects may be neglected, it is well known that convection begins in the form of a supercritical bifurcation to rolls. Non-Boussinesq behaviour destroys the symmetry of the basic state, and through a subcritical bifurcation leads to the formation of hexagonal cells. Here we discuss the influence of regulation of the lower surface temperature by means of a control mechanism, made up of a combination of a proportional linear and nonlinear controller, on the stability of the hexagonal cell pattern.

  18. Rotating non-Boussinesq Rayleigh-Benard convection

    NASA Astrophysics Data System (ADS)

    Moroz, Vadim Vladimir

    This thesis makes quantitative predictions about the formation and stability of hexagonal and roll patterns in convecting system unbounded in horizontal direction. Starting from the Navier-Stokes, heat and continuity equations, the convection problem is then reduced to normal form equations using equivariant bifurcation theory. The relative stabilities of patterns lying on a hexagonal lattice in Fourier space are then determined using appropriate amplitude equations, with coefficients obtained via asymptotic expansion of the governing partial differential equations, with the conducting state being the base state, and the control parameter and the non-Boussinesq effects being small. The software package Mathematica was used to calculate amplitude coefficients of the appropriate coupled Ginzburg-Landau equations for the rigid-rigid and free-free case. A Galerkin code (initial version of which was written by W. Pesch et al.) is used to determine pattern stability further from onset and for strongly non-Boussinesq fluids. Specific predictions about the stability of hexagon and roll patterns for realistic experimental conditions are made. The dependence of the stability of the convective patterns on the Rayleigh number, planform wavenumber and the rotation rate is studied. Long- and shortwave instabilities, both steady and oscillatory, are identified. For small Prandtl numbers oscillatory sideband instabilities are found already very close to onset. A resonant mode interaction in hexagonal patterns arising in non-Boussinesq Rayleigh-Benard convection is studied using symmetry group methods. The lowest-order coupling terms for interacting patterns are identified. A bifurcation analysis of the resulting system of equations shows that the bifurcation is transcritical. Stability properties of resulting patterns are discussed. It is found that for some fluid properties the traditional hexagon convection solution does not exist. Analytical results are supported by numerical

  19. Bäcklund transformations for the Boussinesq equation and merging solitons

    NASA Astrophysics Data System (ADS)

    Rasin, Alexander G.; Schiff, Jeremy

    2017-08-01

    The Bäcklund transformation (BT) for the ‘good’ Boussinesq equation and its superposition principles are presented and applied. Unlike other standard integrable equations, the Boussinesq equation does not have a strictly algebraic superposition principle for 2 BTs, but it does for 3. We present this and discuss associated lattice systems. Applying the BT to the trivial solution generates both standard solitons and what we call ‘merging solitons’—solutions in which two solitary waves (with related speeds) merge into a single one. We use the superposition principles to generate a variety of interesting solutions, including superpositions of a merging soliton with 1 or 2 regular solitons, and solutions that develop a singularity in finite time which then disappears at a later finite time. We prove a Wronskian formula for the solutions obtained by applying a general sequence of BTs on the trivial solution. Finally, we obtain the standard conserved quantities of the Boussinesq equation from the BT, and show how the hierarchy of local symmetries follows in a simple manner from the superposition principle for 3 BTs.

  20. Four-level conservative finite-difference schemes for Boussinesq paradigm equation

    NASA Astrophysics Data System (ADS)

    Kolkovska, N.

    2013-10-01

    In this paper a two-parametric family of four level conservative finite difference schemes is constructed for the multidimensional Boussinesq paradigm equation. The schemes are explicit in the sense that no inner iterations are needed for evaluation of the numerical solution. The preservation of the discrete energy with this method is proved. The schemes have been numerically tested on one soliton propagation model and two solitons interaction model. The numerical experiments demonstrate that the proposed family of schemes has second order of convergence in space and time steps in the discrete maximal norm.

  1. Study of analytical method to seek for exact solutions of variant Boussinesq equations.

    PubMed

    Khan, Kamruzzaman; Akbar, M Ali

    2014-01-01

    In this paper, we have been acquired the soliton solutions of the Variant Boussinesq equations. Primarily, we have used the enhanced (G'/G)-expansion method to find exact solutions of Variant Boussinesq equations. Then, we attain some exact solutions including soliton solutions, hyperbolic and trigonometric function solutions of this equation. 35 K99; 35P05; 35P99.

  2. On conservation laws for a generalized Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Anco, S.; Rosa, M.; Gandarias, M. L.

    2017-07-01

    In this work, we study a Boussinesq equation with a strong damping term from the point of view of the Lie theory. By using the low order conservation laws we apply the conservation laws multiplier method to the associated potential systems.

  3. A numerical study on the non-Boussinesq effect in the natural convection in horizontal annulus

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Cao, Yuhui

    2018-04-01

    In the present study, the non-Boussinesq effect in the thermal convection in an air-filled horizontal concentric annulus is studied numerically by using the variable property-based lattice Boltzmann flux solver (VPLBFS), with the radial temperature difference ratio of 1.0, the radius ratio of 2.0, and the Rayleigh number in the range 104 ≤ Ra ≤ 106. Several solutions are obtained by using the standard form or simplified versions of the VPLBFS, including the real solution with the total variation in fluid properties considered, named as the variable property solution (VPS), the constant property solution (CPS) based on the Boussinesq approximation, the solution with variable dynamic viscosity (VVS), the solution based on the partial Boussinesq approximation (PBAS), the solution with variable thermal conductivity (VCS) and the solution with variable fluid density (VDS). The discrepancy between these solutions is analyzed to illuminate the influence of the non-Boussinesq effects induced by partial or total variation in fluid properties on flow instability behaviors and heat transfer characteristics. The present study reveals the complicated flow instability behavior under non-Boussinesq conditions and its tight association with heat transfer characteristics. Also, it demonstrates the necessity of considering the integral effect of the total variation in fluid properties and highlights the essential role of the fluid density variation.

  4. Renormalization Group Theory of Bolgiano Scaling in Boussinesq Turbulence

    NASA Technical Reports Server (NTRS)

    Rubinstein, Robert

    1994-01-01

    Bolgiano scaling in Boussinesq turbulence is analyzed using the Yakhot-Orszag renormalization group. For this purpose, an isotropic model is introduced. Scaling exponents are calculated by forcing the temperature equation so that the temperature variance flux is constant in the inertial range. Universal amplitudes associated with the scaling laws are computed by expanding about a logarithmic theory. Connections between this formalism and the direct interaction approximation are discussed. It is suggested that the Yakhot-Orszag theory yields a lowest order approximate solution of a regularized direct interaction approximation which can be corrected by a simple iterative procedure.

  5. Celeris: A GPU-accelerated open source software with a Boussinesq-type wave solver for real-time interactive simulation and visualization

    NASA Astrophysics Data System (ADS)

    Tavakkol, Sasan; Lynett, Patrick

    2017-08-01

    In this paper, we introduce an interactive coastal wave simulation and visualization software, called Celeris. Celeris is an open source software which needs minimum preparation to run on a Windows machine. The software solves the extended Boussinesq equations using a hybrid finite volume-finite difference method and supports moving shoreline boundaries. The simulation and visualization are performed on the GPU using Direct3D libraries, which enables the software to run faster than real-time. Celeris provides a first-of-its-kind interactive modeling platform for coastal wave applications and it supports simultaneous visualization with both photorealistic and colormapped rendering capabilities. We validate our software through comparison with three standard benchmarks for non-breaking and breaking waves.

  6. Solutions and conservation laws for a Kaup-Boussinesq system

    NASA Astrophysics Data System (ADS)

    Motsepa, Tanki; Abudiab, Mufid; Khalique, Chaudry Masood

    2017-07-01

    In this work we study a Kaup-Boussinesq system, which is used in the analysis of long waves in shallow water. Travelling wave solutions are obtained by using direct integration. Secondly, conservation laws are derived by using the multiplier method.

  7. Numerical investigation of sixth order Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Kolkovska, N.; Vucheva, V.

    2017-10-01

    We propose a family of conservative finite difference schemes for the Boussinesq equation with sixth order dispersion terms. The schemes are of second order of approximation. The method is conditionally stable with a mild restriction τ = O(h) on the step sizes. Numerical tests are performed for quadratic and cubic nonlinearities. The numerical experiments show second order of convergence of the discrete solution to the exact one.

  8. Nonlocal symmetry and explicit solutions from the CRE method of the Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Zhao, Zhonglong; Han, Bo

    2018-04-01

    In this paper, we analyze the integrability of the Boussinesq equation by using the truncated Painlevé expansion and the CRE method. Based on the truncated Painlevé expansion, the nonlocal symmetry and Bäcklund transformation of this equation are obtained. A prolonged system is introduced to localize the nonlocal symmetry to the local Lie point symmetry. It is proved that the Boussinesq equation is CRE solvable. The two-solitary-wave fusion solutions, single soliton solutions and soliton-cnoidal wave solutions are presented by means of the Bäcklund transformations.

  9. Existence and Non-uniqueness of Global Weak Solutions to Inviscid Primitive and Boussinesq Equations

    NASA Astrophysics Data System (ADS)

    Chiodaroli, Elisabetta; Michálek, Martin

    2017-08-01

    We consider the initial value problem for the inviscid Primitive and Boussinesq equations in three spatial dimensions. We recast both systems as an abstract Euler-type system and apply the methods of convex integration of De Lellis and Székelyhidi to show the existence of infinitely many global weak solutions of the studied equations for general initial data. We also introduce an appropriate notion of dissipative solutions and show the existence of suitable initial data which generate infinitely many dissipative solutions.

  10. New compacton soliton solutions and solitary patterns solutions of nonlinearly dispersive Boussinesq equations

    NASA Astrophysics Data System (ADS)

    Yan, Zhenya; Bluman, George

    2002-11-01

    The special exact solutions of nonlinearly dispersive Boussinesq equations (called B( m, n) equations), utt- uxx- a( un) xx+ b( um) xxxx=0, is investigated by using four direct ansatze. As a result, abundant new compactons: solitons with the absence of infinite wings, solitary patterns solutions having infinite slopes or cups, solitary waves and singular periodic wave solutions of these two equations are obtained. The variant is extended to include linear dispersion to support compactons and solitary patterns in the linearly dispersive Boussinesq equations with m=1. Moreover, another new compacton solution of the special case, B(2,2) equation, is also found.

  11. Random attractor of non-autonomous stochastic Boussinesq lattice system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhao, Min, E-mail: zhaomin1223@126.com; Zhou, Shengfan, E-mail: zhoushengfan@yahoo.com

    2015-09-15

    In this paper, we first consider the existence of tempered random attractor for second-order non-autonomous stochastic lattice dynamical system of nonlinear Boussinesq equations effected by time-dependent coupled coefficients and deterministic forces and multiplicative white noise. Then, we establish the upper semicontinuity of random attractors as the intensity of noise approaches zero.

  12. Rigorous Numerics for ill-posed PDEs: Periodic Orbits in the Boussinesq Equation

    NASA Astrophysics Data System (ADS)

    Castelli, Roberto; Gameiro, Marcio; Lessard, Jean-Philippe

    2018-04-01

    In this paper, we develop computer-assisted techniques for the analysis of periodic orbits of ill-posed partial differential equations. As a case study, our proposed method is applied to the Boussinesq equation, which has been investigated extensively because of its role in the theory of shallow water waves. The idea is to use the symmetry of the solutions and a Newton-Kantorovich type argument (the radii polynomial approach) to obtain rigorous proofs of existence of the periodic orbits in a weighted ℓ1 Banach space of space-time Fourier coefficients with exponential decay. We present several computer-assisted proofs of the existence of periodic orbits at different parameter values.

  13. Exact solutions of fractional mBBM equation and coupled system of fractional Boussinesq-Burgers

    NASA Astrophysics Data System (ADS)

    Javeed, Shumaila; Saif, Summaya; Waheed, Asif; Baleanu, Dumitru

    2018-06-01

    The new exact solutions of nonlinear fractional partial differential equations (FPDEs) are established by adopting first integral method (FIM). The Riemann-Liouville (R-L) derivative and the local conformable derivative definitions are used to deal with the fractional order derivatives. The proposed method is applied to get exact solutions for space-time fractional modified Benjamin-Bona-Mahony (mBBM) equation and coupled time-fractional Boussinesq-Burgers equation. The suggested technique is easily applicable and effectual which can be implemented successfully to obtain the solutions for different types of nonlinear FPDEs.

  14. Simulation of Wave and Current Processes Using Novel, Phase Resolving Models

    DTIC Science & Technology

    2013-09-30

    fundamental technical approach is to represent nearshore water wave systems by retaining Boussinesq scaling assumptions, but without any assumption of... Boussinesq approach that allows for much more freedom in determining the system properties. The resulting systems can have two forms: a classic...of a pressure-Poisson approach to Boussinesq systems . The wave generation-absorption system has now been shown to provide highly accurate results

  15. Symmetry Reductions, Integrability and Solitary Wave Solutions to High-Order Modified Boussinesq Equations with Damping Term

    NASA Astrophysics Data System (ADS)

    Yan, Zhen-Ya; Xie, Fu-Ding; Zhang, Hong-Qing

    2001-07-01

    Both the direct method due to Clarkson and Kruskal and the improved direct method due to Lou are extended to reduce the high-order modified Boussinesq equation with the damping term (HMBEDT) arising in the general Fermi-Pasta-Ulam model. As a result, several types of similarity reductions are obtained. It is easy to show that the nonlinear wave equation is not integrable under the sense of Ablowitz's conjecture from the reduction results obtained. In addition, kink-shaped solitary wave solutions, which are of important physical significance, are found for HMBEDT based on the obtained reduction equation. The project supported by National Natural Science Foundation of China under Grant No. 19572022, the National Key Basic Research Development Project Program of China under Grant No. G1998030600 and Doctoral Foundation of China under Grant No. 98014119

  16. Nonlocal Symmetries, Consistent Riccati Expansion, and Analytical Solutions of the Variant Boussinesq System

    NASA Astrophysics Data System (ADS)

    Feng, Lian-Li; Tian, Shou-Fu; Zhang, Tian-Tian; Zhou, Jun

    2017-07-01

    Under investigation in this paper is the variant Boussinesq system, which describes the propagation of surface long wave towards two directions in a certain deep trough. With the help of the truncated Painlevé expansion, we construct its nonlocal symmetry, Bäcklund transformation, and Schwarzian form, respectively. The nonlocal symmetries can be localised to provide the corresponding nonlocal group, and finite symmetry transformations and similarity reductions are computed. Furthermore, we verify that the variant Boussinesq system is solvable via the consistent Riccati expansion (CRE). By considering the consistent tan-function expansion (CTE), which is a special form of CRE, the interaction solutions between soliton and cnoidal periodic wave are explicitly studied.

  17. Generalized Boussinesq-Scriven surface fluid model with curvature dissipation for liquid surfaces and membranes.

    PubMed

    Aguilar Gutierrez, Oscar F; Herrera Valencia, Edtson E; Rey, Alejandro D

    2017-10-01

    Curvature dissipation is relevant in synthetic and biological processes, from fluctuations in semi-flexible polymer solutions, to buckling of liquid columns, tomembrane cell wall functioning. We present a micromechanical model of curvature dissipation relevant to fluid membranes and liquid surfaces based on a parallel surface parameterization and a stress constitutive equation appropriate for anisotropic fluids and fluid membranes.The derived model, aimed at high curvature and high rate of change of curvature in liquid surfaces and membranes, introduces additional viscous modes not included in the widely used 2D Boussinesq-Scriven rheological constitutive equation for surface fluids.The kinematic tensors that emerge from theparallel surface parameterization are the interfacial rate of deformation and the surface co-rotational Zaremba-Jaumann derivative of the curvature, which are used to classify all possibledissipative planar and non-planar modes. The curvature dissipation function that accounts for bending, torsion and twist rates is derived and analyzed under several constraints, including the important inextensional bending mode.A representative application of the curvature dissipation model to the periodic oscillation in nano-wrinkled outer hair cells show how and why curvature dissipation decreases with frequency, and why the 100kHz frequency range is selected. These results contribute to characterize curvature dissipation in membranes and liquid surfaces. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Two-layer interfacial flows beyond the Boussinesq approximation: a Hamiltonian approach

    NASA Astrophysics Data System (ADS)

    Camassa, R.; Falqui, G.; Ortenzi, G.

    2017-02-01

    The theory of integrable systems of Hamiltonian PDEs and their near-integrable deformations is used to study evolution equations resulting from vertical-averages of the Euler system for two-layer stratified flows in an infinite two-dimensional channel. The Hamiltonian structure of the averaged equations is obtained directly from that of the Euler equations through the process of Hamiltonian reduction. Long-wave asymptotics together with the Boussinesq approximation of neglecting the fluids’ inertia is then applied to reduce the leading order vertically averaged equations to the shallow-water Airy system, albeit in a non-trivial way. The full non-Boussinesq system for the dispersionless limit can then be viewed as a deformation of this well known equation. In a perturbative study of this deformation, a family of approximate constants of the motion are explicitly constructed and used to find local solutions of the evolution equations by means of hodograph-like formulae.

  19. Boussinesq approximation of the Cahn-Hilliard-Navier-Stokes equations.

    PubMed

    Vorobev, Anatoliy

    2010-11-01

    We use the Cahn-Hilliard approach to model the slow dissolution dynamics of binary mixtures. An important peculiarity of the Cahn-Hilliard-Navier-Stokes equations is the necessity to use the full continuity equation even for a binary mixture of two incompressible liquids due to dependence of mixture density on concentration. The quasicompressibility of the governing equations brings a short time-scale (quasiacoustic) process that may not affect the slow dynamics but may significantly complicate the numerical treatment. Using the multiple-scale method we separate the physical processes occurring on different time scales and, ultimately, derive the equations with the filtered-out quasiacoustics. The derived equations represent the Boussinesq approximation of the Cahn-Hilliard-Navier-Stokes equations. This approximation can be further employed as a universal theoretical model for an analysis of slow thermodynamic and hydrodynamic evolution of the multiphase systems with strongly evolving and diffusing interfacial boundaries, i.e., for the processes involving dissolution/nucleation, evaporation/condensation, solidification/melting, polymerization, etc.

  20. Boussinesq equations and other systems for small-amplitude long waves in nonlinear dispersive media: II. The nonlinear theory

    NASA Astrophysics Data System (ADS)

    Bona, J. L.; Chen, M.; Saut, J.-C.

    2004-05-01

    In part I of this work (Bona J L, Chen M and Saut J-C 2002 Boussinesq equations and other systems for small-amplitude long waves in nonlinear dispersive media I: Derivation and the linear theory J. Nonlinear Sci. 12 283-318), a four-parameter family of Boussinesq systems was derived to describe the propagation of surface water waves. Similar systems are expected to arise in other physical settings where the dominant aspects of propagation are a balance between the nonlinear effects of convection and the linear effects of frequency dispersion. In addition to deriving these systems, we determined in part I exactly which of them are linearly well posed in various natural function classes. It was argued that linear well-posedness is a natural necessary requirement for the possible physical relevance of the model in question. In this paper, it is shown that the first-order correct models that are linearly well posed are in fact locally nonlinearly well posed. Moreover, in certain specific cases, global well-posedness is established for physically relevant initial data. In part I, higher-order correct models were also derived. A preliminary analysis of a promising subclass of these models shows them to be well posed.

  1. A boussinesq model of natural convection in the human eye and the formation of Krukenberg's spindle.

    PubMed

    Heys, Jeffrey J; Barocas, Victor H

    2002-03-01

    The cornea of the human eye is cooled by the surrounding air and by evaporation of the tear film. The temperature difference between the cornea and the iris (at core body temperature) causes circulation of the aqueous humor in the anterior chamber of the eye. Others have suggested that the circulation pattern governs the shape of the Krukenberg spindle, a distinctive vertical band of pigment on the posterior cornea surface in some pathologies. We modeled aqueous humor flow the human eye, treating the humor as a Boussinesq fluid and setting the corneal temperature based on infrared surface temperature measurements. The model predicts convection currents in the anterior chamber with velocities comparable to those resulting from forced flow through the gap between the iris and lens. When paths of pigment particles are calculated based on the predicted flow field, the particles circulate throughout the anterior chamber but tend to be near the vertical centerline of the eye for a greatest period of time. Further, the particles are usually in close proximity to the cornea only when they are near the vertical centerline. We conclude that the convective flow pattern of aqueous humor is consistent with a vertical pigment spindle.

  2. A generalized simplest equation method and its application to the Boussinesq-Burgers equation.

    PubMed

    Sudao, Bilige; Wang, Xiaomin

    2015-01-01

    In this paper, a generalized simplest equation method is proposed to seek exact solutions of nonlinear evolution equations (NLEEs). In the method, we chose a solution expression with a variable coefficient and a variable coefficient ordinary differential auxiliary equation. This method can yield a Bäcklund transformation between NLEEs and a related constraint equation. By dealing with the constraint equation, we can derive infinite number of exact solutions for NLEEs. These solutions include the traveling wave solutions, non-traveling wave solutions, multi-soliton solutions, rational solutions, and other types of solutions. As applications, we obtained wide classes of exact solutions for the Boussinesq-Burgers equation by using the generalized simplest equation method.

  3. A Generalized Simplest Equation Method and Its Application to the Boussinesq-Burgers Equation

    PubMed Central

    Sudao, Bilige; Wang, Xiaomin

    2015-01-01

    In this paper, a generalized simplest equation method is proposed to seek exact solutions of nonlinear evolution equations (NLEEs). In the method, we chose a solution expression with a variable coefficient and a variable coefficient ordinary differential auxiliary equation. This method can yield a Bäcklund transformation between NLEEs and a related constraint equation. By dealing with the constraint equation, we can derive infinite number of exact solutions for NLEEs. These solutions include the traveling wave solutions, non-traveling wave solutions, multi-soliton solutions, rational solutions, and other types of solutions. As applications, we obtained wide classes of exact solutions for the Boussinesq-Burgers equation by using the generalized simplest equation method. PMID:25973605

  4. Exact periodic solutions of the sixth-order generalized Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Kamenov, O. Y.

    2009-09-01

    This paper examines a class of nonlinear sixth-order generalized Boussinesq-like equations (SGBE): utt = uxx + 3(u2)xx + uxxxx + αuxxxxxx, α in R, depending on the positive parameter α. Hirota's bilinear transformation method is applied to the above class of non-integrable equations and exact periodic solutions have been obtained. The results confirmed the well-known nonlinear superposition principle.

  5. BASEFLOW SEPARATION BASED ON ANALYTICAL SOLUTIONS OF THE BOUSSINESQ EQUATION. (R824995)

    EPA Science Inventory

    Abstract

    A technique for baseflow separation is presented based on similarity solutions of the Boussinesq equation. The method makes use of the simplifying assumptions that a horizontal impermeable layer underlies a Dupuit aquifer which is drained by a fully penetratin...

  6. Temporal chaos in Boussinesq magnetoconvection

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bekki, Naoaki; Moriguchi, Hirofumi; Fundamental Science, Gifu National College of Technology, Motosu, Gifu 501-0495

    2007-01-15

    Two-dimensional Boussinesq magnetoconvection with idealized stress-free boundary conditions is numerically investigated in order to make clear the difference between chaos and turbulence. It is shown that the long-term behavior of magnetoconvection exhibits spatially coherent and temporally chaotic rolls in marked contrast to highly turbulent fluids. It is also shown that heat transport becomes larger anomalously when the polarity reversal of the magnetic field occurs intermittently in the case of temporally chaotic magnetoconvection. It is found that the Poincare return map of the relative maximum temperature fluctuation of partial differential equations as a function of the preceding maximum resembles the famousmore » Lorenz plot in narrow rolls of magnetoconvection. The chaotic behavior of narrow rolls for individual parameter values robustly persists up to rolls about one fifth as wide as they are high near the codimension-two bifurcation point.« less

  7. Jordan form, parabolicity and other features of change of type transition for hydrodynamic type systems

    NASA Astrophysics Data System (ADS)

    Konopelchenko, B. G.; Ortenzi, G.

    2017-05-01

    Changes of type transitions for two-component hydrodynamic type systems are discussed. It is shown that these systems generically assume the Jordan form (with 2 × 2 Jordan block) on the transition line with hodograph equations becoming parabolic. Conditions which allow or forbid the transition from the hyperbolic domain to elliptic one are discussed. Hamiltonian systems and their special subclasses and equations, such as dispersionless nonlinear Schrödinger, dispersionless Boussinesq, one-dimensional isentropic gas dynamics equations, and nonlinear wave equations are studied. Numerical results concerning the crossing of transition line for the dispersionless Boussinesq equation are also presented.

  8. Explicit Solutions and Bifurcations for a Class of Generalized Boussinesq Wave Equation

    NASA Astrophysics Data System (ADS)

    Ma, Zhi-Min; Sun, Yu-Huai; Liu, Fu-Sheng

    2013-03-01

    In this paper, the generalized Boussinesq wave equation utt — uxx + a(um)xx + buxxxx = 0 is investigated by using the bifurcation theory and the method of phase portraits analysis. Under the different parameter conditions, the exact explicit parametric representations for solitary wave solutions and periodic wave solutions are obtained.

  9. A Unique Finite Element Modeling of the Periodic Wave Transformation over Sloping and Barred Beaches by Beji and Nadaoka's Extended Boussinesq Equations

    PubMed Central

    Jabbari, Mohammad Hadi; Sayehbani, Mesbah; Reisinezhad, Arsham

    2013-01-01

    This paper presents a numerical model based on one-dimensional Beji and Nadaoka's Extended Boussinesq equations for simulation of periodic wave shoaling and its decomposition over morphological beaches. A unique Galerkin finite element and Adams-Bashforth-Moulton predictor-corrector methods are employed for spatial and temporal discretization, respectively. For direct application of linear finite element method in spatial discretization, an auxiliary variable is hereby introduced, and a particular numerical scheme is offered to rewrite the equations in lower-order form. Stability of the suggested numerical method is also analyzed. Subsequently, in order to display the ability of the presented model, four different test cases are considered. In these test cases, dispersive and nonlinearity effects of the periodic waves over sloping beaches and barred beaches, which are the common coastal profiles, are investigated. Outputs are compared with other existing numerical and experimental data. Finally, it is concluded that the current model can be further developed to model any morphological development of coastal profiles. PMID:23853534

  10. Rotating non-Boussinesq convection: oscillating hexagons

    NASA Astrophysics Data System (ADS)

    Moroz, Vadim; Riecke, Hermann; Pesch, Werner

    2000-11-01

    Within weakly nonlinear theory hexagon patterns are expected to undergo a Hopf bifurcation to oscillating hexagons when the chiral symmetry of the system is broken. Quite generally, the oscillating hexagons are expected to exhibit bistability of spatio-temporal defect chaos and periodic dynamics. This regime is described by the complex Ginzburg-Landau equation, which has been investigated theoretically in great detail. Its complex dynamics have, however, not been observed in experiments. Starting from the Navier-Stokes equations with realistic boundary conditions, we derive the three coupled real Ginzburg-Landau equations describing hexagons in rotating non-Boussinesq convection. We use them to provide quantitative results for the wavenumber range of stability of the stationary hexagons as well as the range of existence and stability of the oscillating hexagons. Our investigation is complemented by direct numerical simulations of the Navier-Stokes equations.

  11. Scattering in the Energy Space for Boussinesq Equations

    NASA Astrophysics Data System (ADS)

    Muñoz, Claudio; Poblete, Felipe; Pozo, Juan C.

    2018-01-01

    In this note we show that all small solutions in the energy space of the generalized 1D Boussinesq equation must decay to zero as time tends to infinity, strongly on slightly proper subsets of the space-time light cone. Our result does not require any assumption on the power of the nonlinearity, working even for the supercritical range of scattering. For the proof, we use two new Virial identities in the spirit of works (Kowalczyk et al. in J Am Math Soc 30:769-798, 2017; Kowalczyk et al. in Lett Math Phys 107(5):921-931, 2017). No parity assumption on the initial data is needed.

  12. On quasi-periodic solutions for generalized Boussinesq equation with quadratic nonlinearity

    NASA Astrophysics Data System (ADS)

    Shi, Yanling; Xu, Junxiang; Xu, Xindong

    2015-02-01

    In this paper, one-dimensional generalized Boussinesq equation: utt - uxx + (u2 + uxx)xx = 0 with boundary conditions ux(0, t) = ux(π, t) = uxxx(0, t) = uxxx(π, t) = 0 is considered. It is proved that the equation admits a Whitney smooth family of small-amplitude quasi-periodic solutions with 2-dimensional Diophantine frequencies. The proof is based on an infinite dimensional Kolmogorov-Arnold-Moser theorem and Birkhoff normal form.

  13. Development of a Spot-Application Tool for Rapid, High-Resolution Simulation of Wave-Driven Nearshore Hydrodynamics

    DTIC Science & Technology

    2013-09-30

    flow models, such as Delft3D, with our developed Boussinesq -type model. The vision of this project is to develop an operational tool for the...situ measurements or large-scale wave models. This information will be used to drive the offshore wave boundary condition. • Execute the Boussinesq ...model to match with the Boussinesq -type theory would be one which can simulate sheared and stratified currents due to large-scale (non-wave) forcings

  14. An Accurate and Computationally Efficient Model for Membrane-Type Circular-Symmetric Micro-Hotplates

    PubMed Central

    Khan, Usman; Falconi, Christian

    2014-01-01

    Ideally, the design of high-performance micro-hotplates would require a large number of simulations because of the existence of many important design parameters as well as the possibly crucial effects of both spread and drift. However, the computational cost of FEM simulations, which are the only available tool for accurately predicting the temperature in micro-hotplates, is very high. As a result, micro-hotplate designers generally have no effective simulation-tools for the optimization. In order to circumvent these issues, here, we propose a model for practical circular-symmetric micro-hot-plates which takes advantage of modified Bessel functions, computationally efficient matrix-approach for considering the relevant boundary conditions, Taylor linearization for modeling the Joule heating and radiation losses, and external-region-segmentation strategy in order to accurately take into account radiation losses in the entire micro-hotplate. The proposed model is almost as accurate as FEM simulations and two to three orders of magnitude more computationally efficient (e.g., 45 s versus more than 8 h). The residual errors, which are mainly associated to the undesired heating in the electrical contacts, are small (e.g., few degrees Celsius for an 800 °C operating temperature) and, for important analyses, almost constant. Therefore, we also introduce a computationally-easy single-FEM-compensation strategy in order to reduce the residual errors to about 1 °C. As illustrative examples of the power of our approach, we report the systematic investigation of a spread in the membrane thermal conductivity and of combined variations of both ambient and bulk temperatures. Our model enables a much faster characterization of micro-hotplates and, thus, a much more effective optimization prior to fabrication. PMID:24763214

  15. Accurate HLA type inference using a weighted similarity graph.

    PubMed

    Xie, Minzhu; Li, Jing; Jiang, Tao

    2010-12-14

    The human leukocyte antigen system (HLA) contains many highly variable genes. HLA genes play an important role in the human immune system, and HLA gene matching is crucial for the success of human organ transplantations. Numerous studies have demonstrated that variation in HLA genes is associated with many autoimmune, inflammatory and infectious diseases. However, typing HLA genes by serology or PCR is time consuming and expensive, which limits large-scale studies involving HLA genes. Since it is much easier and cheaper to obtain single nucleotide polymorphism (SNP) genotype data, accurate computational algorithms to infer HLA gene types from SNP genotype data are in need. To infer HLA types from SNP genotypes, the first step is to infer SNP haplotypes from genotypes. However, for the same SNP genotype data set, the haplotype configurations inferred by different methods are usually inconsistent, and it is often difficult to decide which one is true. In this paper, we design an accurate HLA gene type inference algorithm by utilizing SNP genotype data from pedigrees, known HLA gene types of some individuals and the relationship between inferred SNP haplotypes and HLA gene types. Given a set of haplotypes inferred from the genotypes of a population consisting of many pedigrees, the algorithm first constructs a weighted similarity graph based on a new haplotype similarity measure and derives constraint edges from known HLA gene types. Based on the principle that different HLA gene alleles should have different background haplotypes, the algorithm searches for an optimal labeling of all the haplotypes with unknown HLA gene types such that the total weight among the same HLA gene types is maximized. To deal with ambiguous haplotype solutions, we use a genetic algorithm to select haplotype configurations that tend to maximize the same optimization criterion. Our experiments on a previously typed subset of the HapMap data show that the algorithm is highly accurate

  16. An accurate model for predicting high frequency noise of nanoscale NMOS SOI transistors

    NASA Astrophysics Data System (ADS)

    Shen, Yanfei; Cui, Jie; Mohammadi, Saeed

    2017-05-01

    A nonlinear and scalable model suitable for predicting high frequency noise of N-type Metal Oxide Semiconductor (NMOS) transistors is presented. The model is developed for a commercial 45 nm CMOS SOI technology and its accuracy is validated through comparison with measured performance of a microwave low noise amplifier. The model employs the virtual source nonlinear core and adds parasitic elements to accurately simulate the RF behavior of multi-finger NMOS transistors up to 40 GHz. For the first time, the traditional long-channel thermal noise model is supplemented with an injection noise model to accurately represent the noise behavior of these short-channel transistors up to 26 GHz. The developed model is simple and easy to extract, yet very accurate.

  17. Stratified rotating Boussinesq equations in geophysical fluid dynamics: Dynamic bifurcation and periodic solutions

    NASA Astrophysics Data System (ADS)

    Hsia, Chun-Hsiung; Ma, Tian; Wang, Shouhong

    2007-06-01

    The main objective of this article is to study the dynamics of the stratified rotating Boussinesq equations, which are a basic model in geophysical fluid dynamics. First, for the case where the Prandtl number is greater than 1, a complete stability and bifurcation analysis near the first critical Rayleigh number is carried out. Second, for the case where the Prandtl number is smaller than 1, the onset of the Hopf bifurcation near the first critical Rayleigh number is established, leading to the existence of nontrivial periodic solutions. The analysis is based on a newly developed bifurcation and stability theory for nonlinear dynamical systems (both finite and infinite dimensional) by two of the authors [T. Ma and S. Wang, Bifurcation Theory and Applications, World Scientific Series on Nonlinear Sciences Vol. 53 (World Scientific, Singapore, 2005)].

  18. Exact Solutions of Atmospheric (2+1)-Dimensional Nonlinear Incompressible Non-hydrostatic Boussinesq Equations

    NASA Astrophysics Data System (ADS)

    Liu, Ping; Wang, Ya-Xiong; Ren, Bo; Li, Jin-Hua

    2016-12-01

    Exact solutions of the atmospheric (2+1)-dimensional nonlinear incompressible non-hydrostatic Boussinesq (INHB) equations are researched by Combining function expansion and symmetry method. By function expansion, several expansion coefficient equations are derived. Symmetries and similarity solutions are researched in order to obtain exact solutions of the INHB equations. Three types of symmetry reduction equations and similarity solutions for the expansion coefficient equations are proposed. Non-traveling wave solutions for the INHB equations are obtained by symmetries of the expansion coefficient equations. Making traveling wave transformations on expansion coefficient equations, we demonstrate some traveling wave solutions of the INHB equations. The evolutions on the wind velocities, temperature perturbation and pressure perturbation are demonstrated by figures, which demonstrate the periodic evolutions with time and space. Supported by the National Natural Science Foundation of China under Grant Nos. 11305031 and 11305106, and Training Programme Foundation for Outstanding Young Teachers in Higher Education Institutions of Guangdong Province under Grant No. Yq2013205

  19. Initial-boundary layer associated with the nonlinear Darcy-Brinkman-Oberbeck-Boussinesq system

    NASA Astrophysics Data System (ADS)

    Fei, Mingwen; Han, Daozhi; Wang, Xiaoming

    2017-01-01

    In this paper, we study the vanishing Darcy number limit of the nonlinear Darcy-Brinkman-Oberbeck-Boussinesq system (DBOB). This singular perturbation problem involves singular structures both in time and in space giving rise to initial layers, boundary layers and initial-boundary layers. We construct an approximate solution to the DBOB system by the method of multiple scale expansions. The convergence with optimal convergence rates in certain Sobolev norms is established rigorously via the energy method.

  20. Galerkin Spectral Method for the 2D Solitary Waves of Boussinesq Paradigm Equation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Christou, M. A.; Christov, C. I.

    2009-10-29

    We consider the 2D stationary propagating solitary waves of the so-called Boussinesq Paradigm equation. The fourth- order elliptic boundary value problem on infinite interval is solved by a Galerkin spectral method. An iterative procedure based on artificial time ('false transients') and operator splitting is used. Results are obtained for the shapes of the solitary waves for different values of the dispersion parameters for both subcritical and supercritical phase speeds.

  1. A Simple and Accurate Rate-Driven Infiltration Model

    NASA Astrophysics Data System (ADS)

    Cui, G.; Zhu, J.

    2017-12-01

    In this study, we develop a novel Rate-Driven Infiltration Model (RDIMOD) for simulating infiltration into soils. Unlike traditional methods, RDIMOD avoids numerically solving the highly non-linear Richards equation or simply modeling with empirical parameters. RDIMOD employs infiltration rate as model input to simulate one-dimensional infiltration process by solving an ordinary differential equation. The model can simulate the evolutions of wetting front, infiltration rate, and cumulative infiltration on any surface slope including vertical and horizontal directions. Comparing to the results from the Richards equation for both vertical infiltration and horizontal infiltration, RDIMOD simply and accurately predicts infiltration processes for any type of soils and soil hydraulic models without numerical difficulty. Taking into account the accuracy, capability, and computational effectiveness and stability, RDIMOD can be used in large-scale hydrologic and land-atmosphere modeling.

  2. A Novel Approach with Time-Splitting Spectral Technique for the Coupled Schrödinger-Boussinesq Equations Involving Riesz Fractional Derivative

    NASA Astrophysics Data System (ADS)

    Saha Ray, S.

    2017-09-01

    In the present paper the Riesz fractional coupled Schrödinger-Boussinesq (S-B) equations have been solved by the time-splitting Fourier spectral (TSFS) method. This proposed technique is utilized for discretizing the Schrödinger like equation and further, a pseudospectral discretization has been employed for the Boussinesq-like equation. Apart from that an implicit finite difference approach has also been proposed to compare the results with the solutions obtained from the time-splitting technique. Furthermore, the time-splitting method is proved to be unconditionally stable. The error norms along with the graphical solutions have also been presented here. Supported by NBHM, Mumbai, under Department of Atomic Energy, Government of India vide Grant No. 2/48(7)/2015/NBHM (R.P.)/R&D II/11403

  3. On multi-graded-index soliton solutions for the Boussinesq-Burgers equations in optical communications

    NASA Astrophysics Data System (ADS)

    Abdel-Gawad, H. I.; Tantawy, M.

    2017-02-01

    Very recently, multi-solitary long waves for the homogeneous Boussinesq-Burgers equations (BBEs) were studied. Here its found that the time dependent coefficients (BBEs), shows multi-graded-index solitons waves, which are graded refractive index profile and can offer a new route for high-power lasers and transmission. They should increase data rates in low-cost telecommunications systems. Further, that (BBEs) show long periodic solitons waves in communications and television antennas.

  4. On the Asymptotic Regimes and the Strongly Stratified Limit of Rotating Boussinesq Equations

    NASA Technical Reports Server (NTRS)

    Babin, A.; Mahalov, A.; Nicolaenko, B.; Zhou, Y.

    1997-01-01

    Asymptotic regimes of geophysical dynamics are described for different Burger number limits. Rotating Boussinesq equations are analyzed in the asymptotic limit, of strong stratification in the Burger number of order one situation as well as in the asymptotic regime of strong stratification and weak rotation. It is shown that in both regimes horizontally averaged buoyancy variable is an adiabatic invariant for the full Boussinesq system. Spectral phase shift corrections to the buoyancy time scale associated with vertical shearing of this invariant are deduced. Statistical dephasing effects induced by turbulent processes on inertial-gravity waves are evidenced. The 'split' of the energy transfer of the vortical and the wave components is established in the Craya-Herring cyclic basis. As the Burger number increases from zero to infinity, we demonstrate gradual unfreezing of energy cascades for ageostrophic dynamics. The energy spectrum and the anisotropic spectral eddy viscosity are deduced with an explicit dependence on the anisotropic rotation/stratification time scale which depends on the vertical aspect ratio parameter. Intermediate asymptotic regime corresponding to strong stratification and weak rotation is analyzed where the effects of weak rotation are accounted for by an asymptotic expansion with full control (saturation) of vertical shearing. The regularizing effect of weak rotation differs from regularizations based on vertical viscosity. Two scalar prognostic equations for ageostrophic components (divergent velocity potential and geostrophic departure ) are obtained.

  5. Rogue waves in the multicomponent Mel'nikov system and multicomponent Schrödinger-Boussinesq system

    NASA Astrophysics Data System (ADS)

    Sun, Baonan; Lian, Zhan

    2018-02-01

    By virtue of the bilinear method and the KP hierarchy reduction technique, exact explicit rational solutions of the multicomponent Mel'nikov equation and the multicomponent Schrödinger-Boussinesq equation are constructed, which contain multicomponent short waves and single-component long wave. For the multicomponent Mel'nikov equation, the fundamental rational solutions possess two different behaviours: lump and rogue wave. It is shown that the fundamental (simplest) rogue waves are line localised waves which arise from the constant background with a line profile and then disappear into the constant background again. The fundamental line rogue waves can be classified into three: bright, intermediate and dark line rogue waves. Two subclasses of non-fundamental rogue waves, i.e., multirogue waves and higher-order rogue waves are discussed. The multirogue waves describe interaction of several fundamental line rogue waves, in which interesting wave patterns appear in the intermediate time. Higher-order rogue waves exhibit dynamic behaviours that the wave structures start from lump and then retreat back to it. Moreover, by taking the parameter constraints further, general higher-order rogue wave solutions for the multicomponent Schrödinger-Boussinesq system are generated.

  6. Analytic solution for the space-time fractional Klein-Gordon and coupled conformable Boussinesq equations

    NASA Astrophysics Data System (ADS)

    Shallal, Muhannad A.; Jabbar, Hawraz N.; Ali, Khalid K.

    2018-03-01

    In this paper, we constructed a travelling wave solution for space-time fractional nonlinear partial differential equations by using the modified extended Tanh method with Riccati equation. The method is used to obtain analytic solutions for the space-time fractional Klein-Gordon and coupled conformable space-time fractional Boussinesq equations. The fractional complex transforms and the properties of modified Riemann-Liouville derivative have been used to convert these equations into nonlinear ordinary differential equations.

  7. New superfield extension of Boussinesq and its (x,t) interchanged equation from odd Poisson bracket

    NASA Astrophysics Data System (ADS)

    Palit, S.; Chowdhury, A. Roy

    1995-08-01

    A new superfield extension of the Boussinesq equation and its corresponding (x,t) interchanged variant are deduced from the odd Poisson-bracket-formalism, which is similar to the antibracket of Batalin and Vilkovisky. In the former case we obtain the equation deduced by Figueroa-O'Farrill et al from a different approach. In each case we have deduced the bi-Hamiltonian structure and some basic symmetries associated with them.

  8. Initial-boundary value problem to 2D Boussinesq equations for MHD convection with stratification effects

    NASA Astrophysics Data System (ADS)

    Bian, Dongfen; Liu, Jitao

    2017-12-01

    This paper is concerned with the initial-boundary value problem to 2D magnetohydrodynamics-Boussinesq system with the temperature-dependent viscosity, thermal diffusivity and electrical conductivity. First, we establish the global weak solutions under the minimal initial assumption. Then by imposing higher regularity assumption on the initial data, we obtain the global strong solution with uniqueness. Moreover, the exponential decay rates of weak solutions and strong solution are obtained respectively.

  9. Conservation laws and conserved quantities for (1+1)D linearized Boussinesq equations

    NASA Astrophysics Data System (ADS)

    Carvalho, Cindy; Harley, Charis

    2017-05-01

    Conservation laws and physical conserved quantities for the (1+1)D linearized Boussinesq equations at a constant water depth are presented. These equations describe incompressible, inviscid, irrotational fluid flow in the form of a non steady solitary wave. A systematic multiplier approach is used to obtain the conservation laws of the system of third order partial differential equations (PDEs) in dimensional form. Physical conserved quantities are derived by integrating the conservation laws in the direction of wave propagation and imposing decaying boundary conditions in the horizontal direction. One of these is a newly discovered conserved quantity which relates to an energy flux density.

  10. A Short Proof of the Large Time Energy Growth for the Boussinesq System

    NASA Astrophysics Data System (ADS)

    Brandolese, Lorenzo; Mouzouni, Charafeddine

    2017-10-01

    We give a direct proof of the fact that the L^p-norms of global solutions of the Boussinesq system in R^3 grow large as t→ ∞ for 1

  11. Noise-induced switching near a depth two heteroclinic network and an application to Boussinesq convection.

    PubMed

    Ashwin, Peter; Podvigina, Olga

    2010-06-01

    We investigate the robust heteroclinic dynamics arising in a system of ordinary differential equations in R(4) with symmetry [Formula in text]. This system arises from the normal form reduction of a 1: squate root of 2 mode interaction for Boussinesq convection. We investigate the structure of a particular robust heteroclinic attractor with "depth two connections" from equilibria to subcycles as well as connections between equilibria. The "subcycle" is not asymptotically stable, due to nearby trajectories undertaking an "excursion," but it is a Milnor attractor, meaning that a positive measure set of nearby initial conditions converges to the subcycle. We investigate the dynamics in the presence of noise and find a number of interesting properties. We confirm that typical trajectories wind around the subcycle with very occasional excursions near a depth two connection. The frequency of excursions depends on noise intensity in a subtle manner; in particular, for anisotropic noise, the depth two connection may be visited much more often than for isotropic noise, and more generally the long term statistics of the system depends not only on the noise strength but also on the anisotropy of the noise. Similar properties are confirmed in simulations of Boussinesq convection for parameters giving an attractor with depth two connections. (c) 2010 American Institute of Physics.

  12. Modeling Surfzone/Inner-shelf Exchange

    DTIC Science & Technology

    2013-09-30

    goal here is the use a wave-resolving Boussinesq model to figure out how to parameterize the vorticity generation due to short-crested breaking of...individual waves. The Boussinesq model funwaveC used here, developed by the PI and distributed as open-source software, has been val- idated in ONR funded...shading of bottom bathymetry, mooring locations (green squares) and the local co-ordinate system (black arrows). Positive x is directed towards the

  13. Mental models accurately predict emotion transitions.

    PubMed

    Thornton, Mark A; Tamir, Diana I

    2017-06-06

    Successful social interactions depend on people's ability to predict others' future actions and emotions. People possess many mechanisms for perceiving others' current emotional states, but how might they use this information to predict others' future states? We hypothesized that people might capitalize on an overlooked aspect of affective experience: current emotions predict future emotions. By attending to regularities in emotion transitions, perceivers might develop accurate mental models of others' emotional dynamics. People could then use these mental models of emotion transitions to predict others' future emotions from currently observable emotions. To test this hypothesis, studies 1-3 used data from three extant experience-sampling datasets to establish the actual rates of emotional transitions. We then collected three parallel datasets in which participants rated the transition likelihoods between the same set of emotions. Participants' ratings of emotion transitions predicted others' experienced transitional likelihoods with high accuracy. Study 4 demonstrated that four conceptual dimensions of mental state representation-valence, social impact, rationality, and human mind-inform participants' mental models. Study 5 used 2 million emotion reports on the Experience Project to replicate both of these findings: again people reported accurate models of emotion transitions, and these models were informed by the same four conceptual dimensions. Importantly, neither these conceptual dimensions nor holistic similarity could fully explain participants' accuracy, suggesting that their mental models contain accurate information about emotion dynamics above and beyond what might be predicted by static emotion knowledge alone.

  14. Mental models accurately predict emotion transitions

    PubMed Central

    Thornton, Mark A.; Tamir, Diana I.

    2017-01-01

    Successful social interactions depend on people’s ability to predict others’ future actions and emotions. People possess many mechanisms for perceiving others’ current emotional states, but how might they use this information to predict others’ future states? We hypothesized that people might capitalize on an overlooked aspect of affective experience: current emotions predict future emotions. By attending to regularities in emotion transitions, perceivers might develop accurate mental models of others’ emotional dynamics. People could then use these mental models of emotion transitions to predict others’ future emotions from currently observable emotions. To test this hypothesis, studies 1–3 used data from three extant experience-sampling datasets to establish the actual rates of emotional transitions. We then collected three parallel datasets in which participants rated the transition likelihoods between the same set of emotions. Participants’ ratings of emotion transitions predicted others’ experienced transitional likelihoods with high accuracy. Study 4 demonstrated that four conceptual dimensions of mental state representation—valence, social impact, rationality, and human mind—inform participants’ mental models. Study 5 used 2 million emotion reports on the Experience Project to replicate both of these findings: again people reported accurate models of emotion transitions, and these models were informed by the same four conceptual dimensions. Importantly, neither these conceptual dimensions nor holistic similarity could fully explain participants’ accuracy, suggesting that their mental models contain accurate information about emotion dynamics above and beyond what might be predicted by static emotion knowledge alone. PMID:28533373

  15. N=2 supersymmetric a=4-Korteweg-de Vries hierarchy derived via Gardner's deformation of Kaup-Boussinesq equation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hussin, V.; Kiselev, A. V.; Krutov, A. O.

    2010-08-15

    We consider the problem of constructing Gardner's deformations for the N=2 supersymmetric a=4-Korteweg-de Vries (SKdV) equation; such deformations yield recurrence relations between the super-Hamiltonians of the hierarchy. We prove the nonexistence of supersymmetry-invariant deformations that retract to Gardner's formulas for the Korteweg-de Vries (KdV) with equation under the component reduction. At the same time, we propose a two-step scheme for the recursive production of the integrals of motion for the N=2, a=4-SKdV. First, we find a new Gardner's deformation of the Kaup-Boussinesq equation, which is contained in the bosonic limit of the superhierarchy. This yields the recurrence relation between themore » Hamiltonians of the limit, whence we determine the bosonic super-Hamiltonians of the full N=2, a=4-SKdV hierarchy. Our method is applicable toward the solution of Gardner's deformation problems for other supersymmetric KdV-type systems.« less

  16. On Chorin's Method for Stationary Solutions of the Oberbeck-Boussinesq Equation

    NASA Astrophysics Data System (ADS)

    Kagei, Yoshiyuki; Nishida, Takaaki

    2017-06-01

    Stability of stationary solutions of the Oberbeck-Boussinesq system (OB) and the corresponding artificial compressible system is considered. The latter system is obtained by adding the time derivative of the pressure with small parameter ɛ > 0 to the continuity equation of (OB), which was proposed by A. Chorin to find stationary solutions of (OB) numerically. Both systems have the same sets of stationary solutions and the system (OB) is obtained from the artificial compressible one as the limit ɛ \\to 0 which is a singular limit. It is proved that if a stationary solution of the artificial compressible system is stable for sufficiently small ɛ > 0, then it is also stable as a solution of (OB). The converse is proved provided that the velocity field of the stationary solution satisfies some smallness condition.

  17. Orbital stability of solitary waves for generalized Boussinesq equation with two nonlinear terms

    NASA Astrophysics Data System (ADS)

    Zhang, Weiguo; Li, Xiang; Li, Shaowei; Chen, Xu

    2018-06-01

    This paper investigates the orbital stability and instability of solitary waves for the generalized Boussinesq equation with two nonlinear terms. Firstly, according to the theory of Grillakis-Shatah-Strauss orbital stability, we present the general results to judge orbital stability of the solitary waves. Further, we deduce the explicit expression of discrimination d‧‧(c) to judge the stability of the two solitary waves, and give the stable wave speed interval. Moreover, we analyze the influence of the interaction between two nonlinear terms on the stable wave speed interval, and give the maximal stable range for the wave speed. Finally, some conclusions are given in this paper.

  18. Application of the generalized vertical coordinate ocean model for better representing satellite data

    NASA Technical Reports Server (NTRS)

    Song, Y. T.

    2002-01-01

    It is found that two adaptive parametric functions can be introduced into the basic ocean equations for utilizing the optimal or hybrid features of commonly used z-level, terrain- following, isopycnal, and pressure coordinates in numerical ocean models. The two parametric functions are formulated by combining three techniques: the arbitrary vertical coordinate system of Kasahara (1 974), the Jacobian pressure gradient formulation of Song (1 998), and a newly developed metric factor that permits both compressible (non-Boussinesq) and incompressible (Boussinesq) approximations. Based on the new formulation, an adaptive modeling strategy is proposed and a staggered finite volume method is designed to ensure conservation of important physical properties and numerical accuracy. Implementation of the combined techniques to SCRUM (Song and Haidvogel1994) shows that the adaptive modeling strategy can be applied to any existing ocean model without incurring computational expense or altering the original numerical schemes. Such a generalized coordinate model is expected to benefit diverse ocean modelers for easily choosing optimal vertical structures and sharing modeling resources based on a common model platform. Several representing oceanographic problems with different scales and characteristics, such as coastal canyons, basin-scale circulation, and global ocean circulation, are used to demonstrate the model's capability for multiple applications. New results show that the model is capable of simultaneously resolving both Boussinesq and non-Boussinesq, and both small- and large-scale processes well. This talk will focus on its applications of multiple satellite sensing data in eddy-resolving simulations of Asian Marginal Sea and Kurosio. Attention will be given to how Topex/Poseidon SSH, TRMM SST; and GRACE ocean bottom pressure can be correctly represented in a non- Boussinesq model.

  19. NASA Trapezoidal Wing Simulation Using Stress-w and One- and Two-Equation Turbulence Models

    NASA Technical Reports Server (NTRS)

    Rodio, J. J.; Xiao, X; Hassan, H. A.; Rumsey, C. L.

    2014-01-01

    The Wilcox 2006 stress-omega model (also referred to as WilcoxRSM-w2006) has been implemented in the NASA Langley code CFL3D and used to study a variety of 2-D and 3-D configurations. It predicted a variety of basic cases reasonably well, including secondary flow in a supersonic rectangular duct. One- and two-equation turbulence models that employ the Boussinesq constitutive relation were unable to predict this secondary flow accurately because it is driven by normal turbulent stress differences. For the NASA trapezoidal wing at high angles of attack, the WilcoxRSM-w2006 model predicted lower maximum lift than experiment, similar to results of a two-equation model.

  20. Coupling of Coastal Wave Transformation and Computational Fluid Dynamics Models for Seakeeping Analysis

    DTIC Science & Technology

    2017-04-03

    setup in terms of temporal and spatial discretization . The second component was an extension of existing depth-integrated wave models to describe...equations (Abbott, 1976). Discretization schemes involve numerical dispersion and dissipation that distort the true character of the governing equations...represent a leading-order approximation of the Boussinesq-type equations. Tam and Webb (1993) proposed a wavenumber-based discretization scheme to preserve

  1. Accurate lithography simulation model based on convolutional neural networks

    NASA Astrophysics Data System (ADS)

    Watanabe, Yuki; Kimura, Taiki; Matsunawa, Tetsuaki; Nojima, Shigeki

    2017-07-01

    Lithography simulation is an essential technique for today's semiconductor manufacturing process. In order to calculate an entire chip in realistic time, compact resist model is commonly used. The model is established for faster calculation. To have accurate compact resist model, it is necessary to fix a complicated non-linear model function. However, it is difficult to decide an appropriate function manually because there are many options. This paper proposes a new compact resist model using CNN (Convolutional Neural Networks) which is one of deep learning techniques. CNN model makes it possible to determine an appropriate model function and achieve accurate simulation. Experimental results show CNN model can reduce CD prediction errors by 70% compared with the conventional model.

  2. Low-dimensional, morphologically accurate models of subthreshold membrane potential

    PubMed Central

    Kellems, Anthony R.; Roos, Derrick; Xiao, Nan; Cox, Steven J.

    2009-01-01

    The accurate simulation of a neuron’s ability to integrate distributed synaptic input typically requires the simultaneous solution of tens of thousands of ordinary differential equations. For, in order to understand how a cell distinguishes between input patterns we apparently need a model that is biophysically accurate down to the space scale of a single spine, i.e., 1 μm. We argue here that one can retain this highly detailed input structure while dramatically reducing the overall system dimension if one is content to accurately reproduce the associated membrane potential at a small number of places, e.g., at the site of action potential initiation, under subthreshold stimulation. The latter hypothesis permits us to approximate the active cell model with an associated quasi-active model, which in turn we reduce by both time-domain (Balanced Truncation) and frequency-domain (ℋ2 approximation of the transfer function) methods. We apply and contrast these methods on a suite of typical cells, achieving up to four orders of magnitude in dimension reduction and an associated speed-up in the simulation of dendritic democratization and resonance. We also append a threshold mechanism and indicate that this reduction has the potential to deliver an accurate quasi-integrate and fire model. PMID:19172386

  3. An Accurate and Dynamic Computer Graphics Muscle Model

    NASA Technical Reports Server (NTRS)

    Levine, David Asher

    1997-01-01

    A computer based musculo-skeletal model was developed at the University in the departments of Mechanical and Biomedical Engineering. This model accurately represents human shoulder kinematics. The result of this model is the graphical display of bones moving through an appropriate range of motion based on inputs of EMGs and external forces. The need existed to incorporate a geometric muscle model in the larger musculo-skeletal model. Previous muscle models did not accurately represent muscle geometries, nor did they account for the kinematics of tendons. This thesis covers the creation of a new muscle model for use in the above musculo-skeletal model. This muscle model was based on anatomical data from the Visible Human Project (VHP) cadaver study. Two-dimensional digital images from the VHP were analyzed and reconstructed to recreate the three-dimensional muscle geometries. The recreated geometries were smoothed, reduced, and sliced to form data files defining the surfaces of each muscle. The muscle modeling function opened these files during run-time and recreated the muscle surface. The modeling function applied constant volume limitations to the muscle and constant geometry limitations to the tendons.

  4. Analytical Approach to (2+1)-Dimensional Boussinesq Equation and (3+1)-Dimensional Kadomtsev-Petviashvili Equation

    NASA Astrophysics Data System (ADS)

    Sarıaydın, Selin; Yıldırım, Ahmet

    2010-05-01

    In this paper, we studied the solitary wave solutions of the (2+1)-dimensional Boussinesq equation utt -uxx-uyy-(u2)xx-uxxxx = 0 and the (3+1)-dimensional Kadomtsev-Petviashvili (KP) equation uxt -6ux 2 +6uuxx -uxxxx -uyy -uzz = 0. By using this method, an explicit numerical solution is calculated in the form of a convergent power series with easily computable components. To illustrate the application of this method numerical results are derived by using the calculated components of the homotopy perturbation series. The numerical solutions are compared with the known analytical solutions. Results derived from our method are shown graphically.

  5. Hexagonal pattern instabilities in rotating Rayleigh-Bénard convection of a non-Boussinesq fluid: experimental results.

    PubMed

    Guarino, Alessio; Vidal, Valerie

    2004-06-01

    Motivated by the Küppers-Lortz instability of roll patterns in the presence of rotation, we have investigated the effects of rotation on a hexagonal pattern in Rayleigh-Bénard convection. While several theoretical models have been developed, experimental data cannot be found in the literature. In order to check the validity of the predictions and to study the effects of rotation on the behavior of the system, we present experimental results for a non-Boussinesq Rayleigh-Bénard convection with rotation about the vertical axis. Rotation introduces an additional control parameter, namely the dimensionless rotation rate Omega= 2 pi f d(2)/nu, where f is the rotation rate (in Hz), d is the thickness of the cell, and nu is the kinematic viscosity. We observe that the cell rotation induces a slow rotation of the pattern in the opposite direction (approximately Omega x 10(-4) ) in the rotating frame. Moreover, it tends to destroy the convective pattern. No oscillation of the hexagonal pattern over the range of its existence (Omega< or =6) has been observed.

  6. Accurate modelling of unsteady flows in collapsible tubes.

    PubMed

    Marchandise, Emilie; Flaud, Patrice

    2010-01-01

    The context of this paper is the development of a general and efficient numerical haemodynamic tool to help clinicians and researchers in understanding of physiological flow phenomena. We propose an accurate one-dimensional Runge-Kutta discontinuous Galerkin (RK-DG) method coupled with lumped parameter models for the boundary conditions. The suggested model has already been successfully applied to haemodynamics in arteries and is now extended for the flow in collapsible tubes such as veins. The main difference with cardiovascular simulations is that the flow may become supercritical and elastic jumps may appear with the numerical consequence that scheme may not remain monotone if no limiting procedure is introduced. We show that our second-order RK-DG method equipped with an approximate Roe's Riemann solver and a slope-limiting procedure allows us to capture elastic jumps accurately. Moreover, this paper demonstrates that the complex physics associated with such flows is more accurately modelled than with traditional methods such as finite difference methods or finite volumes. We present various benchmark problems that show the flexibility and applicability of the numerical method. Our solutions are compared with analytical solutions when they are available and with solutions obtained using other numerical methods. Finally, to illustrate the clinical interest, we study the emptying process in a calf vein squeezed by contracting skeletal muscle in a normal and pathological subject. We compare our results with experimental simulations and discuss the sensitivity to parameters of our model.

  7. Accurate Modeling Method for Cu Interconnect

    NASA Astrophysics Data System (ADS)

    Yamada, Kenta; Kitahara, Hiroshi; Asai, Yoshihiko; Sakamoto, Hideo; Okada, Norio; Yasuda, Makoto; Oda, Noriaki; Sakurai, Michio; Hiroi, Masayuki; Takewaki, Toshiyuki; Ohnishi, Sadayuki; Iguchi, Manabu; Minda, Hiroyasu; Suzuki, Mieko

    This paper proposes an accurate modeling method of the copper interconnect cross-section in which the width and thickness dependence on layout patterns and density caused by processes (CMP, etching, sputtering, lithography, and so on) are fully, incorporated and universally expressed. In addition, we have developed specific test patterns for the model parameters extraction, and an efficient extraction flow. We have extracted the model parameters for 0.15μm CMOS using this method and confirmed that 10%τpd error normally observed with conventional LPE (Layout Parameters Extraction) was completely dissolved. Moreover, it is verified that the model can be applied to more advanced technologies (90nm, 65nm and 55nm CMOS). Since the interconnect delay variations due to the processes constitute a significant part of what have conventionally been treated as random variations, use of the proposed model could enable one to greatly narrow the guardbands required to guarantee a desired yield, thereby facilitating design closure.

  8. Exact traveling wave solutions of fractional order Boussinesq-like equations by applying Exp-function method

    NASA Astrophysics Data System (ADS)

    Rahmatullah; Ellahi, Rahmat; Mohyud-Din, Syed Tauseef; Khan, Umar

    2018-03-01

    We have computed new exact traveling wave solutions, including complex solutions of fractional order Boussinesq-Like equations, occurring in physical sciences and engineering, by applying Exp-function method. The method is blended with fractional complex transformation and modified Riemann-Liouville fractional order operator. Our obtained solutions are verified by substituting back into their corresponding equations. To the best of our knowledge, no other technique has been reported to cope with the said fractional order nonlinear problems combined with variety of exact solutions. Graphically, fractional order solution curves are shown to be strongly related to each other and most importantly, tend to fixate on their integer order solution curve. Our solutions comprise high frequencies and very small amplitude of the wave responses.

  9. From the paddle to the beach - A Boussinesq shallow water numerical wave tank based on Madsen and Sørensen's equations

    NASA Astrophysics Data System (ADS)

    Orszaghova, Jana; Borthwick, Alistair G. L.; Taylor, Paul H.

    2012-01-01

    This article describes a one-dimensional numerical model of a shallow-water flume with an in-built piston paddle moving boundary wavemaker. The model is based on a set of enhanced Boussinesq equations and the nonlinear shallow water equations. Wave breaking is described approximately, by locally switching to the nonlinear shallow water equations when a critical wave steepness is reached. The moving shoreline is calculated as part of the solution. The piston paddle wavemaker operates on a movable grid, which is Lagrangian on the paddle face and Eulerian away from the paddle. The governing equations are, however, evolved on a fixed mapped grid, and the newly calculated solution is transformed back onto the moving grid via a domain mapping technique. Validation test results are compared against analytical solutions, confirming correct discretisation of the governing equations, wave generation via the numerical paddle, and movement of the wet/dry front. Simulations are presented that reproduce laboratory experiments of wave runup on a plane beach and wave overtopping of a laboratory seawall, involving solitary waves and compact wave groups. In practice, the numerical model is suitable for simulating the propagation of weakly dispersive waves and can additionally model any associated inundation, overtopping or inland flooding within the same simulation.

  10. Traveling wave solutions of the Boussinesq equation via the new approach of generalized (G'/G)-expansion method.

    PubMed

    Alam, Md Nur; Akbar, M Ali; Roshid, Harun-Or-

    2014-01-01

    Exact solutions of nonlinear evolution equations (NLEEs) play a vital role to reveal the internal mechanism of complex physical phenomena. In this work, the exact traveling wave solutions of the Boussinesq equation is studied by using the new generalized (G'/G)-expansion method. Abundant traveling wave solutions with arbitrary parameters are successfully obtained by this method and the wave solutions are expressed in terms of the hyperbolic, trigonometric, and rational functions. It is shown that the new approach of generalized (G'/G)-expansion method is a powerful and concise mathematical tool for solving nonlinear partial differential equations in mathematical physics and engineering. 05.45.Yv, 02.30.Jr, 02.30.Ik.

  11. 3ARM: A Fast, Accurate Radiative Transfer Model for Use in Climate Models

    NASA Technical Reports Server (NTRS)

    Bergstrom, R. W.; Kinne, S.; Sokolik, I. N.; Toon, O. B.; Mlawer, E. J.; Clough, S. A.; Ackerman, T. P.; Mather, J.

    1996-01-01

    A new radiative transfer model combining the efforts of three groups of researchers is discussed. The model accurately computes radiative transfer in a inhomogeneous absorbing, scattering and emitting atmospheres. As an illustration of the model, results are shown for the effects of dust on the thermal radiation.

  12. 3ARM: A Fast, Accurate Radiative Transfer Model for use in Climate Models

    NASA Technical Reports Server (NTRS)

    Bergstrom, R. W.; Kinne, S.; Sokolik, I. N.; Toon, O. B.; Mlawer, E. J.; Clough, S. A.; Ackerman, T. P.; Mather, J.

    1996-01-01

    A new radiative transfer model combining the efforts of three groups of researchers is discussed. The model accurately computes radiative transfer in a inhomogeneous absorbing, scattering and emitting atmospheres. As an illustration of the model, results are shown for the effects of dust on the thermal radiation.

  13. 3ARM: A Fast, Accurate Radiative Transfer Model For Use in Climate Models

    NASA Technical Reports Server (NTRS)

    Bergstrom, R. W.; Kinne, S.; Sokolik, I. N.; Toon, O. B.; Mlawer, E. J.; Clough, S. A.; Ackerman, T. P.; Mather, J.

    1996-01-01

    A new radiative transfer model combining the efforts of three groups of researchers is discussed. The model accurately computes radiative transfer in a inhomogeneous absorbing, scattering and emitting atmospheres. As an illustration of the model, results are shown for the effects of dust on the thermal radiation.

  14. Can phenological models predict tree phenology accurately under climate change conditions?

    NASA Astrophysics Data System (ADS)

    Chuine, Isabelle; Bonhomme, Marc; Legave, Jean Michel; García de Cortázar-Atauri, Inaki; Charrier, Guillaume; Lacointe, André; Améglio, Thierry

    2014-05-01

    The onset of the growing season of trees has been globally earlier by 2.3 days/decade during the last 50 years because of global warming and this trend is predicted to continue according to climate forecast. The effect of temperature on plant phenology is however not linear because temperature has a dual effect on bud development. On one hand, low temperatures are necessary to break bud dormancy, and on the other hand higher temperatures are necessary to promote bud cells growth afterwards. Increasing phenological changes in temperate woody species have strong impacts on forest trees distribution and productivity, as well as crops cultivation areas. Accurate predictions of trees phenology are therefore a prerequisite to understand and foresee the impacts of climate change on forests and agrosystems. Different process-based models have been developed in the last two decades to predict the date of budburst or flowering of woody species. They are two main families: (1) one-phase models which consider only the ecodormancy phase and make the assumption that endodormancy is always broken before adequate climatic conditions for cell growth occur; and (2) two-phase models which consider both the endodormancy and ecodormancy phases and predict a date of dormancy break which varies from year to year. So far, one-phase models have been able to predict accurately tree bud break and flowering under historical climate. However, because they do not consider what happens prior to ecodormancy, and especially the possible negative effect of winter temperature warming on dormancy break, it seems unlikely that they can provide accurate predictions in future climate conditions. It is indeed well known that a lack of low temperature results in abnormal pattern of bud break and development in temperate fruit trees. An accurate modelling of the dormancy break date has thus become a major issue in phenology modelling. Two-phases phenological models predict that global warming should delay

  15. An Accurate Temperature Correction Model for Thermocouple Hygrometers 1

    PubMed Central

    Savage, Michael J.; Cass, Alfred; de Jager, James M.

    1982-01-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques. In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38°C). The model based on calibration at two temperatures is superior to that based on only one calibration. The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25°C, if the calibration slopes are corrected for temperature. PMID:16662241

  16. Rainfall-runoff response informed by exact solutions of Boussinesq equation on hillslopes

    NASA Astrophysics Data System (ADS)

    Bartlett, M. S., Jr.; Porporato, A. M.

    2017-12-01

    The Boussinesq equation offers a powerful approach forunderstanding the flow dynamics of unconfined aquifers. Though this nonlinear equation allows for concise representation of both soil and geomorphological controls on groundwater flow, it has only been solved exactly for a limited number of initial and boundary conditions. These solutions do not include source/sink terms (evapotranspiration, recharge, and seepage to bedrock) and are typically limited to horizontal aquifers. Here we present a class of exact solutions that are general to sloping aquifers and a time varying source/sink term. By incorporating the source/sink term, they may describe aquifers with both time varying recharge over seasonal or weekly time scales, as well as a loss of water from seepage to the bedrock interface, which is a common feature in hillslopes. These new solutions shed light on the hysteretic relationship between streamflow and groundwater and the behavior of the hydrograph recession curves, thus providing a robust basis for deriving a runoff curves for the partition of rainfall into infiltration and runoff.

  17. Radioactive models of type 1 supernovae

    NASA Astrophysics Data System (ADS)

    Schurmann, S. R.

    1983-04-01

    In recent years, considerable progress has been made toward understanding Type I supernovae within the context of radioactive energy input. Much effort has gone into determining the peak magnitude of the supernovae, particularly in the B-band, and its relation to the Hubble constant. If the distances inferred for Type I events are at all accurate, and/or the Hubble constant has a value near 50 km per s per Mpc, it is clear that models must reach a peak magnitude approximately -20 in order to be consistent. The present investigation is concerned with models which achieve peak magnitudes near this value and contain 0.8 solar mass of Ni-56. The B-band light curve declines much more rapidly after peak than the bolometric light curve. The mass and velocity of Ni-56 (at least for the A models) are within the region defined by Axelrod (1980) for configurations which produce acceptable spectra at late times. The models are consistent with the absence of a neutron star after the explosion. There remain, however, many difficult problems.

  18. Radioactive models of type 1 supernovae

    NASA Technical Reports Server (NTRS)

    Schurmann, S. R.

    1983-01-01

    In recent years, considerable progress has been made toward understanding Type I supernovae within the context of radioactive energy input. Much effort has gone into determining the peak magnitude of the supernovae, particularly in the B-band, and its relation to the Hubble constant. If the distances inferred for Type I events are at all accurate, and/or the Hubble constant has a value near 50 km per s per Mpc, it is clear that models must reach a peak magnitude approximately -20 in order to be consistent. The present investigation is concerned with models which achieve peak magnitudes near this value and contain 0.8 solar mass of Ni-56. The B-band light curve declines much more rapidly after peak than the bolometric light curve. The mass and velocity of Ni-56 (at least for the A models) are within the region defined by Axelrod (1980) for configurations which produce acceptable spectra at late times. The models are consistent with the absence of a neutron star after the explosion. There remain, however, many difficult problems.

  19. Deep Ocean Warming Assessed from Altimeters, GRACE, 3 In-situ Measurements, and a Non-Boussinesq OGCM

    NASA Technical Reports Server (NTRS)

    Song, Y. Tony; Colberg, Frank

    2011-01-01

    Observational surveys have shown significant oceanic bottom water warming, but they are too spatially and temporally sporadic to quantify the deep ocean contribution to the present-day sea level rise (SLR). In this study, altimetry sea surface height (SSH), Gravity Recovery and Climate Experiment (GRACE) ocean mass, and in situ upper ocean (0-700 m) steric height have been assessed for their seasonal variability and trend maps. It is shown that neither the global mean nor the regional trends of altimetry SLR can be explained by the upper ocean steric height plus the GRACE ocean mass. A non-Boussinesq ocean general circulation model (OGCM), allowing the sea level to rise as a direct response to the heat added into the ocean, is then used to diagnose the deep ocean steric height. Constrained by sea surface temperature data and the top of atmosphere (TOA) radiation measurements, the model reproduces the observed upper ocean heat content well. Combining the modeled deep ocean steric height with observational upper ocean data gives the full depth steric height. Adding a GRACE-estimated mass trend, the data-model combination explains not only the altimetry global mean SLR but also its regional trends fairly well. The deep ocean warming is mostly prevalent in the Atlantic and Indian oceans, and along the Antarctic Circumpolar Current, suggesting a strong relation to the oceanic circulation and dynamics. Its comparison with available bottom water measurements shows reasonably good agreement, indicating that deep ocean warming below 700 m might have contributed 1.1 mm/yr to the global mean SLR or one-third of the altimeter-observed rate of 3.11 +/- 0.6 mm/yr over 1993-2008.

  20. Improved image quality in pinhole SPECT by accurate modeling of the point spread function in low magnification systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pino, Francisco; Roé, Nuria; Aguiar, Pablo, E-mail: pablo.aguiar.fernandez@sergas.es

    2015-02-15

    Purpose: Single photon emission computed tomography (SPECT) has become an important noninvasive imaging technique in small-animal research. Due to the high resolution required in small-animal SPECT systems, the spatially variant system response needs to be included in the reconstruction algorithm. Accurate modeling of the system response should result in a major improvement in the quality of reconstructed images. The aim of this study was to quantitatively assess the impact that an accurate modeling of spatially variant collimator/detector response has on image-quality parameters, using a low magnification SPECT system equipped with a pinhole collimator and a small gamma camera. Methods: Threemore » methods were used to model the point spread function (PSF). For the first, only the geometrical pinhole aperture was included in the PSF. For the second, the septal penetration through the pinhole collimator was added. In the third method, the measured intrinsic detector response was incorporated. Tomographic spatial resolution was evaluated and contrast, recovery coefficients, contrast-to-noise ratio, and noise were quantified using a custom-built NEMA NU 4–2008 image-quality phantom. Results: A high correlation was found between the experimental data corresponding to intrinsic detector response and the fitted values obtained by means of an asymmetric Gaussian distribution. For all PSF models, resolution improved as the distance from the point source to the center of the field of view increased and when the acquisition radius diminished. An improvement of resolution was observed after a minimum of five iterations when the PSF modeling included more corrections. Contrast, recovery coefficients, and contrast-to-noise ratio were better for the same level of noise in the image when more accurate models were included. Ring-type artifacts were observed when the number of iterations exceeded 12. Conclusions: Accurate modeling of the PSF improves resolution, contrast, and

  1. ACCURATE ORBITAL INTEGRATION OF THE GENERAL THREE-BODY PROBLEM BASED ON THE D'ALEMBERT-TYPE SCHEME

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Minesaki, Yukitaka

    2013-03-15

    We propose an accurate orbital integration scheme for the general three-body problem that retains all conserved quantities except angular momentum. The scheme is provided by an extension of the d'Alembert-type scheme for constrained autonomous Hamiltonian systems. Although the proposed scheme is merely second-order accurate, it can precisely reproduce some periodic, quasiperiodic, and escape orbits. The Levi-Civita transformation plays a role in designing the scheme.

  2. Integration of coastal inundation modeling from storm tides to individual waves

    NASA Astrophysics Data System (ADS)

    Li, Ning; Roeber, Volker; Yamazaki, Yoshiki; Heitmann, Troy W.; Bai, Yefei; Cheung, Kwok Fai

    2014-11-01

    Modeling of storm-induced coastal inundation has primarily focused on the surge generated by atmospheric pressure and surface winds with phase-averaged effects of the waves as setup. Through an interoperable model package, we investigate the role of phase-resolving wave processes in simulation of coastal flood hazards. A spectral ocean wave model describes generation and propagation of storm waves from deep to intermediate water, while a non-hydrostatic storm-tide model has the option to couple with a spectral coastal wave model for computation of phase-averaged processes in a near-shore region. The ocean wave and storm-tide models can alternatively provide the wave spectrum and the surface elevation as the boundary and initial conditions for a nested Boussinesq model. Additional surface-gradient terms in the Boussinesq equations maintain the quasi-steady, non-uniform storm tide for modeling of phase-resolving surf and swash-zone processes as well as combined tide, surge, and wave inundation. The two nesting schemes are demonstrated through a case study of Hurricane Iniki, which made landfall on the Hawaiian Island of Kauai in 1992. With input from a parametric hurricane model and global reanalysis and tidal datasets, the two approaches produce comparable significant wave heights and phase-averaged surface elevations in the surf zone. The nesting of the Boussinesq model provides a seamless approach to augment the inundation due to the individual waves in matching the recorded debris line along the coast.

  3. Optimal Cluster Mill Pass Scheduling With an Accurate and Rapid New Strip Crown Model

    NASA Astrophysics Data System (ADS)

    Malik, Arif S.; Grandhi, Ramana V.; Zipf, Mark E.

    2007-05-01

    Besides the requirement to roll coiled sheet at high levels of productivity, the optimal pass scheduling of cluster-type reversing cold mills presents the added challenge of assigning mill parameters that facilitate the best possible strip flatness. The pressures of intense global competition, and the requirements for increasingly thinner, higher quality specialty sheet products that are more difficult to roll, continue to force metal producers to commission innovative flatness-control technologies. This means that during the on-line computerized set-up of rolling mills, the mathematical model should not only determine the minimum total number of passes and maximum rolling speed, it should simultaneously optimize the pass-schedule so that desired flatness is assured, either by manual or automated means. In many cases today, however, on-line prediction of strip crown and corresponding flatness for the complex cluster-type rolling mills is typically addressed either by trial and error, by approximate deflection models for equivalent vertical roll-stacks, or by non-physical pattern recognition style models. The abundance of the aforementioned methods is largely due to the complexity of cluster-type mill configurations and the lack of deflection models with sufficient accuracy and speed for on-line use. Without adequate assignment of the pass-schedule set-up parameters, it may be difficult or impossible to achieve the required strip flatness. In this paper, we demonstrate optimization of cluster mill pass-schedules using a new accurate and rapid strip crown model. This pass-schedule optimization includes computations of the predicted strip thickness profile to validate mathematical constraints. In contrast to many of the existing methods for on-line prediction of strip crown and flatness on cluster mills, the demonstrated method requires minimal prior tuning and no extensive training with collected mill data. To rapidly and accurately solve the multi-contact problem

  4. Experimental evaluation of a recursive model identification technique for type 1 diabetes.

    PubMed

    Finan, Daniel A; Doyle, Francis J; Palerm, Cesar C; Bevier, Wendy C; Zisser, Howard C; Jovanovic, Lois; Seborg, Dale E

    2009-09-01

    A model-based controller for an artificial beta cell requires an accurate model of the glucose-insulin dynamics in type 1 diabetes subjects. To ensure the robustness of the controller for changing conditions (e.g., changes in insulin sensitivity due to illnesses, changes in exercise habits, or changes in stress levels), the model should be able to adapt to the new conditions by means of a recursive parameter estimation technique. Such an adaptive strategy will ensure that the most accurate model is used for the current conditions, and thus the most accurate model predictions are used in model-based control calculations. In a retrospective analysis, empirical dynamic autoregressive exogenous input (ARX) models were identified from glucose-insulin data for nine type 1 diabetes subjects in ambulatory conditions. Data sets consisted of continuous (5-minute) glucose concentration measurements obtained from a continuous glucose monitor, basal insulin infusion rates and times and amounts of insulin boluses obtained from the subjects' insulin pumps, and subject-reported estimates of the times and carbohydrate content of meals. Two identification techniques were investigated: nonrecursive, or batch methods, and recursive methods. Batch models were identified from a set of training data, whereas recursively identified models were updated at each sampling instant. Both types of models were used to make predictions of new test data. For the purpose of comparison, model predictions were compared to zero-order hold (ZOH) predictions, which were made by simply holding the current glucose value constant for p steps into the future, where p is the prediction horizon. Thus, the ZOH predictions are model free and provide a base case for the prediction metrics used to quantify the accuracy of the model predictions. In theory, recursive identification techniques are needed only when there are changing conditions in the subject that require model adaptation. Thus, the identification and

  5. Ensemble predictive model for more accurate soil organic carbon spectroscopic estimation

    NASA Astrophysics Data System (ADS)

    Vašát, Radim; Kodešová, Radka; Borůvka, Luboš

    2017-07-01

    A myriad of signal pre-processing strategies and multivariate calibration techniques has been explored in attempt to improve the spectroscopic prediction of soil organic carbon (SOC) over the last few decades. Therefore, to come up with a novel, more powerful, and accurate predictive approach to beat the rank becomes a challenging task. However, there may be a way, so that combine several individual predictions into a single final one (according to ensemble learning theory). As this approach performs best when combining in nature different predictive algorithms that are calibrated with structurally different predictor variables, we tested predictors of two different kinds: 1) reflectance values (or transforms) at each wavelength and 2) absorption feature parameters. Consequently we applied four different calibration techniques, two per each type of predictors: a) partial least squares regression and support vector machines for type 1, and b) multiple linear regression and random forest for type 2. The weights to be assigned to individual predictions within the ensemble model (constructed as a weighted average) were determined by an automated procedure that ensured the best solution among all possible was selected. The approach was tested at soil samples taken from surface horizon of four sites differing in the prevailing soil units. By employing the ensemble predictive model the prediction accuracy of SOC improved at all four sites. The coefficient of determination in cross-validation (R2cv) increased from 0.849, 0.611, 0.811 and 0.644 (the best individual predictions) to 0.864, 0.650, 0.824 and 0.698 for Site 1, 2, 3 and 4, respectively. Generally, the ensemble model affected the final prediction so that the maximal deviations of predicted vs. observed values of the individual predictions were reduced, and thus the correlation cloud became thinner as desired.

  6. Dynamic Transitions and Baroclinic Instability for 3D Continuously Stratified Boussinesq Flows

    NASA Astrophysics Data System (ADS)

    Şengül, Taylan; Wang, Shouhong

    2018-02-01

    The main objective of this article is to study the nonlinear stability and dynamic transitions of the basic (zonal) shear flows for the three-dimensional continuously stratified rotating Boussinesq model. The model equations are fundamental equations in geophysical fluid dynamics, and dynamics associated with their basic zonal shear flows play a crucial role in understanding many important geophysical fluid dynamical processes, such as the meridional overturning oceanic circulation and the geophysical baroclinic instability. In this paper, first we derive a threshold for the energy stability of the basic shear flow, and obtain a criterion for local nonlinear stability in terms of the critical horizontal wavenumbers and the system parameters such as the Froude number, the Rossby number, the Prandtl number and the strength of the shear flow. Next, we demonstrate that the system always undergoes a dynamic transition from the basic shear flow to either a spatiotemporal oscillatory pattern or circle of steady states, as the shear strength of the basic flow crosses a critical threshold. Also, we show that the dynamic transition can be either continuous or catastrophic, and is dictated by the sign of a transition number, fully characterizing the nonlinear interactions of different modes. Both the critical shear strength and the transition number are functions of the system parameters. A systematic numerical method is carried out to explore transition in different flow parameter regimes. In particular, our numerical investigations show the existence of a hypersurface which separates the parameter space into regions where the basic shear flow is stable and unstable. Numerical investigations also yield that the selection of horizontal wave indices is determined only by the aspect ratio of the box. We find that the system admits only critical eigenmodes with roll patterns aligned with the x-axis. Furthermore, numerically we encountered continuous transitions to multiple

  7. Fast and Accurate Circuit Design Automation through Hierarchical Model Switching.

    PubMed

    Huynh, Linh; Tagkopoulos, Ilias

    2015-08-21

    In computer-aided biological design, the trifecta of characterized part libraries, accurate models and optimal design parameters is crucial for producing reliable designs. As the number of parts and model complexity increase, however, it becomes exponentially more difficult for any optimization method to search the solution space, hence creating a trade-off that hampers efficient design. To address this issue, we present a hierarchical computer-aided design architecture that uses a two-step approach for biological design. First, a simple model of low computational complexity is used to predict circuit behavior and assess candidate circuit branches through branch-and-bound methods. Then, a complex, nonlinear circuit model is used for a fine-grained search of the reduced solution space, thus achieving more accurate results. Evaluation with a benchmark of 11 circuits and a library of 102 experimental designs with known characterization parameters demonstrates a speed-up of 3 orders of magnitude when compared to other design methods that provide optimality guarantees.

  8. Accurate electromagnetic modeling of terahertz detectors

    NASA Technical Reports Server (NTRS)

    Focardi, Paolo; McGrath, William R.

    2004-01-01

    Twin slot antennas coupled to superconducting devices have been developed over the years as single pixel detectors in the terahertz (THz) frequency range for space-based and astronomy applications. Used either for mixing or direct detection, they have been object of several investigations, and are currently being developed for several missions funded or co-funded by NASA. Although they have shown promising performance in terms of noise and sensitivity, so far they have usually also shown a considerable disagreement in terms of performance between calculations and measurements, especially when considering center frequency and bandwidth. In this paper we present a thorough and accurate electromagnetic model of complete detector and we compare the results of calculations with measurements. Starting from a model of the embedding circuit, the effect of all the other elements in the detector in the coupled power have been analyzed. An extensive variety of measured and calculated data, as presented in this paper, demonstrates the effectiveness and reliability of the electromagnetic model at frequencies between 600 GHz and 2.5THz.

  9. Accurate Modeling of Ionospheric Electromagnetic Fields Generated by a Low Altitude VLF Transmitter

    DTIC Science & Technology

    2009-03-31

    AFRL-RV-HA-TR-2009-1055 Accurate Modeling of Ionospheric Electromagnetic Fields Generated by a Low Altitude VLF Transmitter ...m (or even 500 m) at mid to high latitudes . At low latitudes , the FDTD model exhibits variations that make it difficult to determine a reliable...Scientific, Final 3. DATES COVERED (From - To) 02-08-2006 – 31-12-2008 4. TITLE AND SUBTITLE Accurate Modeling of Ionospheric Electromagnetic Fields

  10. An accurate halo model for fitting non-linear cosmological power spectra and baryonic feedback models

    NASA Astrophysics Data System (ADS)

    Mead, A. J.; Peacock, J. A.; Heymans, C.; Joudaki, S.; Heavens, A. F.

    2015-12-01

    We present an optimized variant of the halo model, designed to produce accurate matter power spectra well into the non-linear regime for a wide range of cosmological models. To do this, we introduce physically motivated free parameters into the halo-model formalism and fit these to data from high-resolution N-body simulations. For a variety of Λ cold dark matter (ΛCDM) and wCDM models, the halo-model power is accurate to ≃ 5 per cent for k ≤ 10h Mpc-1 and z ≤ 2. An advantage of our new halo model is that it can be adapted to account for the effects of baryonic feedback on the power spectrum. We demonstrate this by fitting the halo model to power spectra from the OWLS (OverWhelmingly Large Simulations) hydrodynamical simulation suite via parameters that govern halo internal structure. We are able to fit all feedback models investigated at the 5 per cent level using only two free parameters, and we place limits on the range of these halo parameters for feedback models investigated by the OWLS simulations. Accurate predictions to high k are vital for weak-lensing surveys, and these halo parameters could be considered nuisance parameters to marginalize over in future analyses to mitigate uncertainty regarding the details of feedback. Finally, we investigate how lensing observables predicted by our model compare to those from simulations and from HALOFIT for a range of k-cuts and feedback models and quantify the angular scales at which these effects become important. Code to calculate power spectra from the model presented in this paper can be found at https://github.com/alexander-mead/hmcode.

  11. Fast and accurate computation of system matrix for area integral model-based algebraic reconstruction technique

    NASA Astrophysics Data System (ADS)

    Zhang, Shunli; Zhang, Dinghua; Gong, Hao; Ghasemalizadeh, Omid; Wang, Ge; Cao, Guohua

    2014-11-01

    Iterative algorithms, such as the algebraic reconstruction technique (ART), are popular for image reconstruction. For iterative reconstruction, the area integral model (AIM) is more accurate for better reconstruction quality than the line integral model (LIM). However, the computation of the system matrix for AIM is more complex and time-consuming than that for LIM. Here, we propose a fast and accurate method to compute the system matrix for AIM. First, we calculate the intersection of each boundary line of a narrow fan-beam with pixels in a recursive and efficient manner. Then, by grouping the beam-pixel intersection area into six types according to the slopes of the two boundary lines, we analytically compute the intersection area of the narrow fan-beam with the pixels in a simple algebraic fashion. Overall, experimental results show that our method is about three times faster than the Siddon algorithm and about two times faster than the distance-driven model (DDM) in computation of the system matrix. The reconstruction speed of our AIM-based ART is also faster than the LIM-based ART that uses the Siddon algorithm and DDM-based ART, for one iteration. The fast reconstruction speed of our method was accomplished without compromising the image quality.

  12. Allele-sharing models: LOD scores and accurate linkage tests.

    PubMed

    Kong, A; Cox, N J

    1997-11-01

    Starting with a test statistic for linkage analysis based on allele sharing, we propose an associated one-parameter model. Under general missing-data patterns, this model allows exact calculation of likelihood ratios and LOD scores and has been implemented by a simple modification of existing software. Most important, accurate linkage tests can be performed. Using an example, we show that some previously suggested approaches to handling less than perfectly informative data can be unacceptably conservative. Situations in which this model may not perform well are discussed, and an alternative model that requires additional computations is suggested.

  13. Allele-sharing models: LOD scores and accurate linkage tests.

    PubMed Central

    Kong, A; Cox, N J

    1997-01-01

    Starting with a test statistic for linkage analysis based on allele sharing, we propose an associated one-parameter model. Under general missing-data patterns, this model allows exact calculation of likelihood ratios and LOD scores and has been implemented by a simple modification of existing software. Most important, accurate linkage tests can be performed. Using an example, we show that some previously suggested approaches to handling less than perfectly informative data can be unacceptably conservative. Situations in which this model may not perform well are discussed, and an alternative model that requires additional computations is suggested. PMID:9345087

  14. A Weibull statistics-based lignocellulose saccharification model and a built-in parameter accurately predict lignocellulose hydrolysis performance.

    PubMed

    Wang, Mingyu; Han, Lijuan; Liu, Shasha; Zhao, Xuebing; Yang, Jinghua; Loh, Soh Kheang; Sun, Xiaomin; Zhang, Chenxi; Fang, Xu

    2015-09-01

    Renewable energy from lignocellulosic biomass has been deemed an alternative to depleting fossil fuels. In order to improve this technology, we aim to develop robust mathematical models for the enzymatic lignocellulose degradation process. By analyzing 96 groups of previously published and newly obtained lignocellulose saccharification results and fitting them to Weibull distribution, we discovered Weibull statistics can accurately predict lignocellulose saccharification data, regardless of the type of substrates, enzymes and saccharification conditions. A mathematical model for enzymatic lignocellulose degradation was subsequently constructed based on Weibull statistics. Further analysis of the mathematical structure of the model and experimental saccharification data showed the significance of the two parameters in this model. In particular, the λ value, defined the characteristic time, represents the overall performance of the saccharification system. This suggestion was further supported by statistical analysis of experimental saccharification data and analysis of the glucose production levels when λ and n values change. In conclusion, the constructed Weibull statistics-based model can accurately predict lignocellulose hydrolysis behavior and we can use the λ parameter to assess the overall performance of enzymatic lignocellulose degradation. Advantages and potential applications of the model and the λ value in saccharification performance assessment were discussed. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Fast and accurate calculation of dilute quantum gas using Uehling–Uhlenbeck model equation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yano, Ryosuke, E-mail: ryosuke.yano@tokiorisk.co.jp

    The Uehling–Uhlenbeck (U–U) model equation is studied for the fast and accurate calculation of a dilute quantum gas. In particular, the direct simulation Monte Carlo (DSMC) method is used to solve the U–U model equation. DSMC analysis based on the U–U model equation is expected to enable the thermalization to be accurately obtained using a small number of sample particles and the dilute quantum gas dynamics to be calculated in a practical time. Finally, the applicability of DSMC analysis based on the U–U model equation to the fast and accurate calculation of a dilute quantum gas is confirmed by calculatingmore » the viscosity coefficient of a Bose gas on the basis of the Green–Kubo expression and the shock layer of a dilute Bose gas around a cylinder.« less

  16. Nonlinear layered lattice model and generalized solitary waves in imperfectly bonded structures.

    PubMed

    Khusnutdinova, Karima R; Samsonov, Alexander M; Zakharov, Alexey S

    2009-05-01

    We study nonlinear waves in a two-layered imperfectly bonded structure using a nonlinear lattice model. The key element of the model is an anharmonic chain of oscillating dipoles, which can be viewed as a basic lattice analog of a one-dimensional macroscopic waveguide. Long nonlinear longitudinal waves in a layered lattice with a soft middle (or bonding) layer are governed by a system of coupled Boussinesq-type equations. For this system we find conservation laws and show that pure solitary waves, which exist in a single equation and can exist in the coupled system in the symmetric case, are structurally unstable and are replaced with generalized solitary waves.

  17. Cross hole GPR traveltime inversion using a fast and accurate neural network as a forward model

    NASA Astrophysics Data System (ADS)

    Mejer Hansen, Thomas

    2017-04-01

    Probabilistic formulated inverse problems can be solved using Monte Carlo based sampling methods. In principle both advanced prior information, such as based on geostatistics, and complex non-linear forward physical models can be considered. However, in practice these methods can be associated with huge computational costs that in practice limit their application. This is not least due to the computational requirements related to solving the forward problem, where the physical response of some earth model has to be evaluated. Here, it is suggested to replace a numerical complex evaluation of the forward problem, with a trained neural network that can be evaluated very fast. This will introduce a modeling error, that is quantified probabilistically such that it can be accounted for during inversion. This allows a very fast and efficient Monte Carlo sampling of the solution to an inverse problem. We demonstrate the methodology for first arrival travel time inversion of cross hole ground-penetrating radar (GPR) data. An accurate forward model, based on 2D full-waveform modeling followed by automatic travel time picking, is replaced by a fast neural network. This provides a sampling algorithm three orders of magnitude faster than using the full forward model, and considerably faster, and more accurate, than commonly used approximate forward models. The methodology has the potential to dramatically change the complexity of the types of inverse problems that can be solved using non-linear Monte Carlo sampling techniques.

  18. Accurate Modeling of Galaxy Clustering on Small Scales: Testing the Standard ΛCDM + Halo Model

    NASA Astrophysics Data System (ADS)

    Sinha, Manodeep; Berlind, Andreas A.; McBride, Cameron; Scoccimarro, Roman

    2015-01-01

    The large-scale distribution of galaxies can be explained fairly simply by assuming (i) a cosmological model, which determines the dark matter halo distribution, and (ii) a simple connection between galaxies and the halos they inhabit. This conceptually simple framework, called the halo model, has been remarkably successful at reproducing the clustering of galaxies on all scales, as observed in various galaxy redshift surveys. However, none of these previous studies have carefully modeled the systematics and thus truly tested the halo model in a statistically rigorous sense. We present a new accurate and fully numerical halo model framework and test it against clustering measurements from two luminosity samples of galaxies drawn from the SDSS DR7. We show that the simple ΛCDM cosmology + halo model is not able to simultaneously reproduce the galaxy projected correlation function and the group multiplicity function. In particular, the more luminous sample shows significant tension with theory. We discuss the implications of our findings and how this work paves the way for constraining galaxy formation by accurate simultaneous modeling of multiple galaxy clustering statistics.

  19. Accurate path integration in continuous attractor network models of grid cells.

    PubMed

    Burak, Yoram; Fiete, Ila R

    2009-02-01

    Grid cells in the rat entorhinal cortex display strikingly regular firing responses to the animal's position in 2-D space and have been hypothesized to form the neural substrate for dead-reckoning. However, errors accumulate rapidly when velocity inputs are integrated in existing models of grid cell activity. To produce grid-cell-like responses, these models would require frequent resets triggered by external sensory cues. Such inadequacies, shared by various models, cast doubt on the dead-reckoning potential of the grid cell system. Here we focus on the question of accurate path integration, specifically in continuous attractor models of grid cell activity. We show, in contrast to previous models, that continuous attractor models can generate regular triangular grid responses, based on inputs that encode only the rat's velocity and heading direction. We consider the role of the network boundary in the integration performance of the network and show that both periodic and aperiodic networks are capable of accurate path integration, despite important differences in their attractor manifolds. We quantify the rate at which errors in the velocity integration accumulate as a function of network size and intrinsic noise within the network. With a plausible range of parameters and the inclusion of spike variability, our model networks can accurately integrate velocity inputs over a maximum of approximately 10-100 meters and approximately 1-10 minutes. These findings form a proof-of-concept that continuous attractor dynamics may underlie velocity integration in the dorsolateral medial entorhinal cortex. The simulations also generate pertinent upper bounds on the accuracy of integration that may be achieved by continuous attractor dynamics in the grid cell network. We suggest experiments to test the continuous attractor model and differentiate it from models in which single cells establish their responses independently of each other.

  20. General high-order breathers and rogue waves in the (3 + 1) -dimensional KP-Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Sun, Baonan; Wazwaz, Abdul-Majid

    2018-11-01

    In this work, we investigate the (3 + 1) -dimensional KP-Boussinesq equation, which can be used to describe the nonlinear dynamic behavior in scientific and engineering applications. We derive general high-order soliton solutions by using the Hirota's bilinear method combined with the perturbation expansion technique. We also obtain periodic solutions comprising of high-order breathers, periodic line waves, and mixed solutions consisting of breathers and periodic line waves upon selecting particular parameter constraints of the obtained soliton solutions. Furthermore, smooth rational solutions are generated by taking a long wave limit of the soliton solutions. These smooth rational solutions include high-order rogue waves, high-order lumps, and hybrid solutions consisting of lumps and line rogue waves. To better understand the dynamical behaviors of these solutions, we discuss some illustrative graphical analyses. It is expected that our results can enrich the dynamical behavior of the (3 + 1) -dimensional nonlinear evolution equations of other forms.

  1. Creation of Anatomically Accurate Computer-Aided Design (CAD) Solid Models from Medical Images

    NASA Technical Reports Server (NTRS)

    Stewart, John E.; Graham, R. Scott; Samareh, Jamshid A.; Oberlander, Eric J.; Broaddus, William C.

    1999-01-01

    Most surgical instrumentation and implants used in the world today are designed with sophisticated Computer-Aided Design (CAD)/Computer-Aided Manufacturing (CAM) software. This software automates the mechanical development of a product from its conceptual design through manufacturing. CAD software also provides a means of manipulating solid models prior to Finite Element Modeling (FEM). Few surgical products are designed in conjunction with accurate CAD models of human anatomy because of the difficulty with which these models are created. We have developed a novel technique that creates anatomically accurate, patient specific CAD solids from medical images in a matter of minutes.

  2. Modeling of large amplitude plasma blobs in three-dimensions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Angus, Justin R.; Umansky, Maxim V.

    2014-01-15

    Fluctuations in fusion boundary and similar plasmas often have the form of filamentary structures, or blobs, that convectively propagate radially. This may lead to the degradation of plasma facing components as well as plasma confinement. Theoretical analysis of plasma blobs usually takes advantage of the so-called Boussinesq approximation of the potential vorticity equation, which greatly simplifies the treatment analytically and numerically. This approximation is only strictly justified when the blob density amplitude is small with respect to that of the background plasma. However, this is not the case for typical plasma blobs in the far scrape-off layer region, where themore » background density is small compared to that of the blob, and results obtained based on the Boussinesq approximation are questionable. In this report, the solution of the full vorticity equation, without the usual Boussinesq approximation, is proposed via a novel numerical approach. The method is used to solve for the evolution of 2D and 3D plasma blobs in a regime where the Boussinesq approximation is not valid. The Boussinesq solution under predicts the cross field transport in 2D. However, in 3D, for parameters typical of current tokamaks, the disparity between the radial cross field transport from the Boussinesq approximation and full solution is virtually non-existent due to the effects of the drift wave instability.« less

  3. Local Debonding and Fiber Breakage in Composite Materials Modeled Accurately

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M.

    2001-01-01

    A prerequisite for full utilization of composite materials in aerospace components is accurate design and life prediction tools that enable the assessment of component performance and reliability. Such tools assist both structural analysts, who design and optimize structures composed of composite materials, and materials scientists who design and optimize the composite materials themselves. NASA Glenn Research Center's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) software package (http://www.grc.nasa.gov/WWW/LPB/mac) addresses this need for composite design and life prediction tools by providing a widely applicable and accurate approach to modeling composite materials. Furthermore, MAC/GMC serves as a platform for incorporating new local models and capabilities that are under development at NASA, thus enabling these new capabilities to progress rapidly to a stage in which they can be employed by the code's end users.

  4. Accurate protein structure modeling using sparse NMR data and homologous structure information.

    PubMed

    Thompson, James M; Sgourakis, Nikolaos G; Liu, Gaohua; Rossi, Paolo; Tang, Yuefeng; Mills, Jeffrey L; Szyperski, Thomas; Montelione, Gaetano T; Baker, David

    2012-06-19

    While information from homologous structures plays a central role in X-ray structure determination by molecular replacement, such information is rarely used in NMR structure determination because it can be incorrect, both locally and globally, when evolutionary relationships are inferred incorrectly or there has been considerable evolutionary structural divergence. Here we describe a method that allows robust modeling of protein structures of up to 225 residues by combining (1)H(N), (13)C, and (15)N backbone and (13)Cβ chemical shift data, distance restraints derived from homologous structures, and a physically realistic all-atom energy function. Accurate models are distinguished from inaccurate models generated using incorrect sequence alignments by requiring that (i) the all-atom energies of models generated using the restraints are lower than models generated in unrestrained calculations and (ii) the low-energy structures converge to within 2.0 Å backbone rmsd over 75% of the protein. Benchmark calculations on known structures and blind targets show that the method can accurately model protein structures, even with very remote homology information, to a backbone rmsd of 1.2-1.9 Å relative to the conventional determined NMR ensembles and of 0.9-1.6 Å relative to X-ray structures for well-defined regions of the protein structures. This approach facilitates the accurate modeling of protein structures using backbone chemical shift data without need for side-chain resonance assignments and extensive analysis of NOESY cross-peak assignments.

  5. Modeling and new equipment definition for the vibration isolation box equipment system

    NASA Technical Reports Server (NTRS)

    Sani, Robert L.

    1993-01-01

    Our MSAD-funded research project is to provide numerical modeling support for the VIBES (Vibration Isolation Box Experiment System) which is an IML2 flight experiment being built by the Japanese research team of Dr. H. Azuma of the Japanese National Aerospace Laboratory. During this reporting period, the following have been accomplished: A semi-consistent mass finite element projection algorithm for 2D and 3D Boussinesq flows has been implemented on Sun, HP And Cray Platforms. The algorithm has better phase speed accuracy than similar finite difference or lumped mass finite element algorithms, an attribute which is essential for addressing realistic g-jitter effects as well as convectively-dominated transient systems. The projection algorithm has been benchmarked against solutions generated via the commercial code FIDAP. The algorithm appears to be accurate as well as computationally efficient. Optimization and potential parallelization studies are underway. Our implementation to date has focused on execution of the basic algorithm with at most a concern for vectorization. The initial time-varying gravity Boussinesq flow simulation is being set up. The mesh is being designed and the input file is being generated. Some preliminary 'small mesh' cases will be attempted on our HP9000/735 while our request to MSAD for supercomputing resources is being addressed. The Japanese research team for VIBES was visited, the current set up and status of the physical experiment was obtained and ongoing E-Mail communication link was established.

  6. Development of mapped stress-field boundary conditions based on a Hill-type muscle model.

    PubMed

    Cardiff, P; Karač, A; FitzPatrick, D; Flavin, R; Ivanković, A

    2014-09-01

    Forces generated in the muscles and tendons actuate the movement of the skeleton. Accurate estimation and application of these musculotendon forces in a continuum model is not a trivial matter. Frequently, musculotendon attachments are approximated as point forces; however, accurate estimation of local mechanics requires a more realistic application of musculotendon forces. This paper describes the development of mapped Hill-type muscle models as boundary conditions for a finite volume model of the hip joint, where the calculated muscle fibres map continuously between attachment sites. The applied muscle forces are calculated using active Hill-type models, where input electromyography signals are determined from gait analysis. Realistic muscle attachment sites are determined directly from tomography images. The mapped muscle boundary conditions, implemented in a finite volume structural OpenFOAM (ESI-OpenCFD, Bracknell, UK) solver, are employed to simulate the mid-stance phase of gait using a patient-specific natural hip joint, and a comparison is performed with the standard point load muscle approach. It is concluded that physiological joint loading is not accurately represented by simplistic muscle point loading conditions; however, when contact pressures are of sole interest, simplifying assumptions with regard to muscular forces may be valid. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Accurate Typing of Human Leukocyte Antigen Class I Genes by Oxford Nanopore Sequencing.

    PubMed

    Liu, Chang; Xiao, Fangzhou; Hoisington-Lopez, Jessica; Lang, Kathrin; Quenzel, Philipp; Duffy, Brian; Mitra, Robi David

    2018-04-03

    Oxford Nanopore Technologies' MinION has expanded the current DNA sequencing toolkit by delivering long read lengths and extreme portability. The MinION has the potential to enable expedited point-of-care human leukocyte antigen (HLA) typing, an assay routinely used to assess the immunologic compatibility between organ donors and recipients, but the platform's high error rate makes it challenging to type alleles with accuracy. We developed and validated accurate typing of HLA by Oxford nanopore (Athlon), a bioinformatic pipeline that i) maps nanopore reads to a database of known HLA alleles, ii) identifies candidate alleles with the highest read coverage at different resolution levels that are represented as branching nodes and leaves of a tree structure, iii) generates consensus sequences by remapping the reads to the candidate alleles, and iv) calls the final diploid genotype by blasting consensus sequences against the reference database. Using two independent data sets generated on the R9.4 flow cell chemistry, Athlon achieved a 100% accuracy in class I HLA typing at the two-field resolution. Copyright © 2018 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  8. Accurate modeling of the hose instability in plasma wakefield accelerators

    DOE PAGES

    Mehrling, T. J.; Benedetti, C.; Schroeder, C. B.; ...

    2018-05-20

    Hosing is a major challenge for the applicability of plasma wakefield accelerators and its modeling is therefore of fundamental importance to facilitate future stable and compact plasma-based particle accelerators. In this contribution, we present a new model for the evolution of the plasma centroid, which enables the accurate investigation of the hose instability in the nonlinear blowout regime. Lastly, it paves the road for more precise and comprehensive studies of hosing, e.g., with drive and witness beams, which were not possible with previous models.

  9. Accurate modeling of the hose instability in plasma wakefield accelerators

    NASA Astrophysics Data System (ADS)

    Mehrling, T. J.; Benedetti, C.; Schroeder, C. B.; Martinez de la Ossa, A.; Osterhoff, J.; Esarey, E.; Leemans, W. P.

    2018-05-01

    Hosing is a major challenge for the applicability of plasma wakefield accelerators and its modeling is therefore of fundamental importance to facilitate future stable and compact plasma-based particle accelerators. In this contribution, we present a new model for the evolution of the plasma centroid, which enables the accurate investigation of the hose instability in the nonlinear blowout regime. It paves the road for more precise and comprehensive studies of hosing, e.g., with drive and witness beams, which were not possible with previous models.

  10. Accurate modeling of the hose instability in plasma wakefield accelerators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mehrling, T. J.; Benedetti, C.; Schroeder, C. B.

    Hosing is a major challenge for the applicability of plasma wakefield accelerators and its modeling is therefore of fundamental importance to facilitate future stable and compact plasma-based particle accelerators. In this contribution, we present a new model for the evolution of the plasma centroid, which enables the accurate investigation of the hose instability in the nonlinear blowout regime. Lastly, it paves the road for more precise and comprehensive studies of hosing, e.g., with drive and witness beams, which were not possible with previous models.

  11. Accurate determination of high-risk coronary lesion type by multidetector cardiac computed tomography.

    PubMed

    Alasnag, Mirvat; Umakanthan, Branavan; Foster, Gary P

    2008-07-01

    Coronary arteriography (CA) is the standard method to image coronary lesions. Multidetector cardiac computerized tomography (MDCT) provides high-resolution images of coronary arteries, allowing a noninvasive alternative to determine lesion type. To date, no studies have assessed the ability of MDCT to categorize coronary lesion types. The objective of this study was to determine the accuracy of lesion type categorization by MDCT using CA as a reference standard. Patients who underwent both MDCT and CA within 2 months of each other were enrolled. MDCT and CA images were reviewed in a blinded fashion. Lesions were categorized according to the SCAI classification system (Types I-IV). The origin, proximal and middle segments of the major arteries were analyzed. Each segment comprised a data point for comparison. Analysis was performed using the Spearman Correlation Test. Four hundred eleven segments were studied, of which 110 had lesions. The lesion distribution was as follows: 35 left anterior descending (LAD), 29 circumflex (Cx), 31 right coronary artery (RCA), 2 ramus intermedius, 8 diagonal, 4 obtuse marginal and 2 left internal mammary arteries. Correlations between MDCT and CA were significant in all major vessels (LAD, Cx, RCA) (p < 0.001). The overall correlation coefficient was 0.67. Concordance was strong for lesion Types II-IV (97%) and poor for Type I (30%). High-risk coronary lesion types can be accurately categorized by MDCT. This ability may allow MDCT to play an important noninvasive role in the planning of coronary interventions.

  12. Accurate analytical modeling of junctionless DG-MOSFET by green's function approach

    NASA Astrophysics Data System (ADS)

    Nandi, Ashutosh; Pandey, Nilesh

    2017-11-01

    An accurate analytical model of Junctionless double gate MOSFET (JL-DG-MOSFET) in the subthreshold regime of operation is developed in this work using green's function approach. The approach considers 2-D mixed boundary conditions and multi-zone techniques to provide an exact analytical solution to 2-D Poisson's equation. The Fourier coefficients are calculated correctly to derive the potential equations that are further used to model the channel current and subthreshold slope of the device. The threshold voltage roll-off is computed from parallel shifts of Ids-Vgs curves between the long channel and short-channel devices. It is observed that the green's function approach of solving 2-D Poisson's equation in both oxide and silicon region can accurately predict channel potential, subthreshold current (Isub), threshold voltage (Vt) roll-off and subthreshold slope (SS) of both long & short channel devices designed with different doping concentrations and higher as well as lower tsi/tox ratio. All the analytical model results are verified through comparisons with TCAD Sentaurus simulation results. It is observed that the model matches quite well with TCAD device simulations.

  13. A new accurate quadratic equation model for isothermal gas chromatography and its comparison with the linear model

    PubMed Central

    Wu, Liejun; Chen, Maoxue; Chen, Yongli; Li, Qing X.

    2013-01-01

    The gas holdup time (tM) is a dominant parameter in gas chromatographic retention models. The difference equation (DE) model proposed by Wu et al. (J. Chromatogr. A 2012, http://dx.doi.org/10.1016/j.chroma.2012.07.077) excluded tM. In the present paper, we propose that the relationship between the adjusted retention time tRZ′ and carbon number z of n-alkanes follows a quadratic equation (QE) when an accurate tM is obtained. This QE model is the same as or better than the DE model for an accurate expression of the retention behavior of n-alkanes and model applications. The QE model covers a larger range of n-alkanes with better curve fittings than the linear model. The accuracy of the QE model was approximately 2–6 times better than the DE model and 18–540 times better than the LE model. Standard deviations of the QE model were approximately 2–3 times smaller than those of the DE model. PMID:22989489

  14. Multi-soliton interaction of a generalized Schrödinger-Boussinesq system in a magnetized plasma

    NASA Astrophysics Data System (ADS)

    Zhao, Xue-Hui; Tian, Bo; Chai, Jun; Wu, Xiao-Yu; Guo, Yong-Jiang

    2017-04-01

    Under investigation in this paper is a generalized Schrödinger-Boussinesq system, which describes the stationary propagation of coupled upper-hybrid waves and magnetoacoustic waves in a magnetized plasma. Bilinear forms, one-, two- and three-soliton solutions are derived by virtue of the Hirota method and symbolic computation. Propagation and interaction for the solitons are illustrated graphically: Coefficients β1^{} and β2^{} can affect the velocities and propagation directions of the solitary waves. Amplitude, velocity and shape of the one solitary wave keep invariant during the propagation, implying that the transport of the energy is stable in the upper-hybrid and magnetoacoustic waves, and amplitude of the upper-hybrid wave is bigger than that of the magnetoacoustic wave. For the upper-hybrid and magnetoacoustic waves, head-on, overtaking and bound-state interaction between the two solitary waves are asymptotically depicted, respectively, indicating that the interaction between the two solitary waves is elastic. Elastic interaction between the bound-state soliton and a single one soliton is also displayed, and interaction among the three solitary waves is all elastic.

  15. Accurate monoenergetic electron parameters of laser wakefield in a bubble model

    NASA Astrophysics Data System (ADS)

    Raheli, A.; Rahmatallahpur, S. H.

    2012-11-01

    A reliable analytical expression for the potential of plasma waves with phase velocities near the speed of light is derived. The presented spheroid cavity model is more consistent than the previous spherical and ellipsoidal model and it explains the mono-energetic electron trajectory more accurately, especially at the relativistic region. As a result, the quasi-mono-energetic electrons output beam interacting with the laser plasma can be more appropriately described with this model.

  16. Preferential access to genetic information from endogenous hominin ancient DNA and accurate quantitative SNP-typing via SPEX

    PubMed Central

    Brotherton, Paul; Sanchez, Juan J.; Cooper, Alan; Endicott, Phillip

    2010-01-01

    The analysis of targeted genetic loci from ancient, forensic and clinical samples is usually built upon polymerase chain reaction (PCR)-generated sequence data. However, many studies have shown that PCR amplification from poor-quality DNA templates can create sequence artefacts at significant levels. With hominin (human and other hominid) samples, the pervasive presence of highly PCR-amplifiable human DNA contaminants in the vast majority of samples can lead to the creation of recombinant hybrids and other non-authentic artefacts. The resulting PCR-generated sequences can then be difficult, if not impossible, to authenticate. In contrast, single primer extension (SPEX)-based approaches can genotype single nucleotide polymorphisms from ancient fragments of DNA as accurately as modern DNA. A single SPEX-type assay can amplify just one of the duplex DNA strands at target loci and generate a multi-fold depth-of-coverage, with non-authentic recombinant hybrids reduced to undetectable levels. Crucially, SPEX-type approaches can preferentially access genetic information from damaged and degraded endogenous ancient DNA templates over modern human DNA contaminants. The development of SPEX-type assays offers the potential for highly accurate, quantitative genotyping from ancient hominin samples. PMID:19864251

  17. Nonlinear multimodal model for TLD of irregular tank geometry and small fluid depth

    NASA Astrophysics Data System (ADS)

    Love, J. S.; Tait, M. J.

    2013-11-01

    Tuned liquid dampers (TLDs) utilize sloshing fluid to absorb and dissipate structural vibrational energy. TLDs of irregular or complex tank geometry may be required in practice to avoid tank interference with fixed structural or mechanical components. The literature offers few analytical models to predict the response of this type of TLD, particularly when the fluid depth is small. In this paper, a multimodal model is developed utilizing a Boussinesq-type modal theory which is valid for small TLD fluid depths. The Bateman-Luke variational principle is employed to develop a system of coupled nonlinear ordinary differential equations which describe the fluid response when the tank is subjected to base excitation. Energy dissipation is incorporated into the model from the inclusion of damping screens. The fluid model is used to describe the response of a 2D structure-TLD system when the structure is subjected to external loading and the TLD tank geometry is irregular.

  18. A pairwise maximum entropy model accurately describes resting-state human brain networks

    PubMed Central

    Watanabe, Takamitsu; Hirose, Satoshi; Wada, Hiroyuki; Imai, Yoshio; Machida, Toru; Shirouzu, Ichiro; Konishi, Seiki; Miyashita, Yasushi; Masuda, Naoki

    2013-01-01

    The resting-state human brain networks underlie fundamental cognitive functions and consist of complex interactions among brain regions. However, the level of complexity of the resting-state networks has not been quantified, which has prevented comprehensive descriptions of the brain activity as an integrative system. Here, we address this issue by demonstrating that a pairwise maximum entropy model, which takes into account region-specific activity rates and pairwise interactions, can be robustly and accurately fitted to resting-state human brain activities obtained by functional magnetic resonance imaging. Furthermore, to validate the approximation of the resting-state networks by the pairwise maximum entropy model, we show that the functional interactions estimated by the pairwise maximum entropy model reflect anatomical connexions more accurately than the conventional functional connectivity method. These findings indicate that a relatively simple statistical model not only captures the structure of the resting-state networks but also provides a possible method to derive physiological information about various large-scale brain networks. PMID:23340410

  19. Accurate polynomial expressions for the density and specific volume of seawater using the TEOS-10 standard

    NASA Astrophysics Data System (ADS)

    Roquet, F.; Madec, G.; McDougall, Trevor J.; Barker, Paul M.

    2015-06-01

    A new set of approximations to the standard TEOS-10 equation of state are presented. These follow a polynomial form, making it computationally efficient for use in numerical ocean models. Two versions are provided, the first being a fit of density for Boussinesq ocean models, and the second fitting specific volume which is more suitable for compressible models. Both versions are given as the sum of a vertical reference profile (6th-order polynomial) and an anomaly (52-term polynomial, cubic in pressure), with relative errors of ∼0.1% on the thermal expansion coefficients. A 75-term polynomial expression is also presented for computing specific volume, with a better accuracy than the existing TEOS-10 48-term rational approximation, especially regarding the sound speed, and it is suggested that this expression represents a valuable approximation of the TEOS-10 equation of state for hydrographic data analysis. In the last section, practical aspects about the implementation of TEOS-10 in ocean models are discussed.

  20. A numerical study of the 3-periodic wave solutions to KdV-type equations

    NASA Astrophysics Data System (ADS)

    Zhang, Yingnan; Hu, Xingbiao; Sun, Jianqing

    2018-02-01

    In this paper, by using the direct method of calculating periodic wave solutions proposed by Akira Nakamura, we present a numerical process to calculate the 3-periodic wave solutions to several KdV-type equations: the Korteweg-de Vries equation, the Sawada-Koterra equation, the Boussinesq equation, the Ito equation, the Hietarinta equation and the (2 + 1)-dimensional Kadomtsev-Petviashvili equation. Some detailed numerical examples are given to show the existence of the three-periodic wave solutions numerically.

  1. Accurate, low-cost 3D-models of gullies

    NASA Astrophysics Data System (ADS)

    Onnen, Nils; Gronz, Oliver; Ries, Johannes B.; Brings, Christine

    2015-04-01

    Soil erosion is a widespread problem in arid and semi-arid areas. The most severe form is the gully erosion. They often cut into agricultural farmland and can make a certain area completely unproductive. To understand the development and processes inside and around gullies, we calculated detailed 3D-models of gullies in the Souss Valley in South Morocco. Near Taroudant, we had four study areas with five gullies different in size, volume and activity. By using a Canon HF G30 Camcorder, we made varying series of Full HD videos with 25fps. Afterwards, we used the method Structure from Motion (SfM) to create the models. To generate accurate models maintaining feasible runtimes, it is necessary to select around 1500-1700 images from the video, while the overlap of neighboring images should be at least 80%. In addition, it is very important to avoid selecting photos that are blurry or out of focus. Nearby pixels of a blurry image tend to have similar color values. That is why we used a MATLAB script to compare the derivatives of the images. The higher the sum of the derivative, the sharper an image of similar objects. MATLAB subdivides the video into image intervals. From each interval, the image with the highest sum is selected. E.g.: 20min. video at 25fps equals 30.000 single images. The program now inspects the first 20 images, saves the sharpest and moves on to the next 20 images etc. Using this algorithm, we selected 1500 images for our modeling. With VisualSFM, we calculated features and the matches between all images and produced a point cloud. Then, MeshLab has been used to build a surface out of it using the Poisson surface reconstruction approach. Afterwards we are able to calculate the size and the volume of the gullies. It is also possible to determine soil erosion rates, if we compare the data with old recordings. The final step would be the combination of the terrestrial data with the data from our aerial photography. So far, the method works well and we

  2. An Optimally Stable and Accurate Second-Order SSP Runge-Kutta IMEX Scheme for Atmospheric Applications

    NASA Astrophysics Data System (ADS)

    Rokhzadi, Arman; Mohammadian, Abdolmajid; Charron, Martin

    2018-01-01

    The objective of this paper is to develop an optimized implicit-explicit (IMEX) Runge-Kutta scheme for atmospheric applications focusing on stability and accuracy. Following the common terminology, the proposed method is called IMEX-SSP2(2,3,2), as it has second-order accuracy and is composed of diagonally implicit two-stage and explicit three-stage parts. This scheme enjoys the Strong Stability Preserving (SSP) property for both parts. This new scheme is applied to nonhydrostatic compressible Boussinesq equations in two different arrangements, including (i) semiimplicit and (ii) Horizontally Explicit-Vertically Implicit (HEVI) forms. The new scheme preserves the SSP property for larger regions of absolute monotonicity compared to the well-studied scheme in the same class. In addition, numerical tests confirm that the IMEX-SSP2(2,3,2) improves the maximum stable time step as well as the level of accuracy and computational cost compared to other schemes in the same class. It is demonstrated that the A-stability property as well as satisfying "second-stage order" and stiffly accurate conditions lead the proposed scheme to better performance than existing schemes for the applications examined herein.

  3. Development of Modified Incompressible Ideal Gas Model for Natural Draft Cooling Tower Flow Simulation

    NASA Astrophysics Data System (ADS)

    Hyhlík, Tomáš

    2018-06-01

    The article deals with the development of incompressible ideal gas like model, which can be used as a part of mathematical model describing natural draft wet-cooling tower flow, heat and mass transfer. It is shown, based on the results of a complex mathematical model of natural draft wet-cooling tower flow, that behaviour of pressure, temperature and density is very similar to the case of hydrostatics of moist air, where heat and mass transfer in the fill zone must be taken into account. The behaviour inside the cooling tower is documented using density, pressure and temperature distributions. The proposed equation for the density is based on the same idea like the incompressible ideal gas model, which is only dependent on temperature, specific humidity and in this case on elevation. It is shown that normalized density difference of the density based on proposed model and density based on the nonsimplified model is in the order of 10-4. The classical incompressible ideal gas model, Boussinesq model and generalised Boussinesq model are also tested. These models show deviation in percentages.

  4. An Accurate Absorption-Based Net Primary Production Model for the Global Ocean

    NASA Astrophysics Data System (ADS)

    Silsbe, G.; Westberry, T. K.; Behrenfeld, M. J.; Halsey, K.; Milligan, A.

    2016-02-01

    As a vital living link in the global carbon cycle, understanding how net primary production (NPP) varies through space, time, and across climatic oscillations (e.g. ENSO) is a key objective in oceanographic research. The continual improvement of ocean observing satellites and data analytics now present greater opportunities for advanced understanding and characterization of the factors regulating NPP. In particular, the emergence of spectral inversion algorithms now permits accurate retrievals of the phytoplankton absorption coefficient (aΦ) from space. As NPP is the efficiency in which absorbed energy is converted into carbon biomass, aΦ measurements circumvents chlorophyll-based empirical approaches by permitting direct and accurate measurements of phytoplankton energy absorption. It has long been recognized, and perhaps underappreciated, that NPP and phytoplankton growth rates display muted variability when normalized to aΦ rather than chlorophyll. Here we present a novel absorption-based NPP model that parameterizes the underlying physiological mechanisms behind this muted variability, and apply this physiological model to the global ocean. Through a comparison against field data from the Hawaii and Bermuda Ocean Time Series, we demonstrate how this approach yields more accurate NPP measurements than other published NPP models. By normalizing NPP to satellite estimates of phytoplankton carbon biomass, this presentation also explores the seasonality of phytoplankton growth rates across several oceanic regions. Finally, we discuss how future advances in remote-sensing (e.g. hyperspectral satellites, LIDAR, autonomous profilers) can be exploited to further improve absorption-based NPP models.

  5. What makes an accurate and reliable subject-specific finite element model? A case study of an elephant femur

    PubMed Central

    Panagiotopoulou, O.; Wilshin, S. D.; Rayfield, E. J.; Shefelbine, S. J.; Hutchinson, J. R.

    2012-01-01

    Finite element modelling is well entrenched in comparative vertebrate biomechanics as a tool to assess the mechanical design of skeletal structures and to better comprehend the complex interaction of their form–function relationships. But what makes a reliable subject-specific finite element model? To approach this question, we here present a set of convergence and sensitivity analyses and a validation study as an example, for finite element analysis (FEA) in general, of ways to ensure a reliable model. We detail how choices of element size, type and material properties in FEA influence the results of simulations. We also present an empirical model for estimating heterogeneous material properties throughout an elephant femur (but of broad applicability to FEA). We then use an ex vivo experimental validation test of a cadaveric femur to check our FEA results and find that the heterogeneous model matches the experimental results extremely well, and far better than the homogeneous model. We emphasize how considering heterogeneous material properties in FEA may be critical, so this should become standard practice in comparative FEA studies along with convergence analyses, consideration of element size, type and experimental validation. These steps may be required to obtain accurate models and derive reliable conclusions from them. PMID:21752810

  6. Accurate pressure gradient calculations in hydrostatic atmospheric models

    NASA Technical Reports Server (NTRS)

    Carroll, John J.; Mendez-Nunez, Luis R.; Tanrikulu, Saffet

    1987-01-01

    A method for the accurate calculation of the horizontal pressure gradient acceleration in hydrostatic atmospheric models is presented which is especially useful in situations where the isothermal surfaces are not parallel to the vertical coordinate surfaces. The present method is shown to be exact if the potential temperature lapse rate is constant between the vertical pressure integration limits. The technique is applied to both the integration of the hydrostatic equation and the computation of the slope correction term in the horizontal pressure gradient. A fixed vertical grid and a dynamic grid defined by the significant levels in the vertical temperature distribution are employed.

  7. An analytic model for accurate spring constant calibration of rectangular atomic force microscope cantilevers.

    PubMed

    Li, Rui; Ye, Hongfei; Zhang, Weisheng; Ma, Guojun; Su, Yewang

    2015-10-29

    Spring constant calibration of the atomic force microscope (AFM) cantilever is of fundamental importance for quantifying the force between the AFM cantilever tip and the sample. The calibration within the framework of thin plate theory undoubtedly has a higher accuracy and broader scope than that within the well-established beam theory. However, thin plate theory-based accurate analytic determination of the constant has been perceived as an extremely difficult issue. In this paper, we implement the thin plate theory-based analytic modeling for the static behavior of rectangular AFM cantilevers, which reveals that the three-dimensional effect and Poisson effect play important roles in accurate determination of the spring constants. A quantitative scaling law is found that the normalized spring constant depends only on the Poisson's ratio, normalized dimension and normalized load coordinate. Both the literature and our refined finite element model validate the present results. The developed model is expected to serve as the benchmark for accurate calibration of rectangular AFM cantilevers.

  8. A Multiscale Red Blood Cell Model with Accurate Mechanics, Rheology, and Dynamics

    PubMed Central

    Fedosov, Dmitry A.; Caswell, Bruce; Karniadakis, George Em

    2010-01-01

    Abstract Red blood cells (RBCs) have highly deformable viscoelastic membranes exhibiting complex rheological response and rich hydrodynamic behavior governed by special elastic and bending properties and by the external/internal fluid and membrane viscosities. We present a multiscale RBC model that is able to predict RBC mechanics, rheology, and dynamics in agreement with experiments. Based on an analytic theory, the modeled membrane properties can be uniquely related to the experimentally established RBC macroscopic properties without any adjustment of parameters. The RBC linear and nonlinear elastic deformations match those obtained in optical-tweezers experiments. The rheological properties of the membrane are compared with those obtained in optical magnetic twisting cytometry, membrane thermal fluctuations, and creep followed by cell recovery. The dynamics of RBCs in shear and Poiseuille flows is tested against experiments and theoretical predictions, and the applicability of the latter is discussed. Our findings clearly indicate that a purely elastic model for the membrane cannot accurately represent the RBC's rheological properties and its dynamics, and therefore accurate modeling of a viscoelastic membrane is necessary. PMID:20483330

  9. A dental vision system for accurate 3D tooth modeling.

    PubMed

    Zhang, Li; Alemzadeh, K

    2006-01-01

    This paper describes an active vision system based reverse engineering approach to extract the three-dimensional (3D) geometric information from dental teeth and transfer this information into Computer-Aided Design/Computer-Aided Manufacture (CAD/CAM) systems to improve the accuracy of 3D teeth models and at the same time improve the quality of the construction units to help patient care. The vision system involves the development of a dental vision rig, edge detection, boundary tracing and fast & accurate 3D modeling from a sequence of sliced silhouettes of physical models. The rig is designed using engineering design methods such as a concept selection matrix and weighted objectives evaluation chart. Reconstruction results and accuracy evaluation are presented on digitizing different teeth models.

  10. Towards Accurate Modelling of Galaxy Clustering on Small Scales: Testing the Standard ΛCDM + Halo Model

    NASA Astrophysics Data System (ADS)

    Sinha, Manodeep; Berlind, Andreas A.; McBride, Cameron K.; Scoccimarro, Roman; Piscionere, Jennifer A.; Wibking, Benjamin D.

    2018-04-01

    Interpreting the small-scale clustering of galaxies with halo models can elucidate the connection between galaxies and dark matter halos. Unfortunately, the modelling is typically not sufficiently accurate for ruling out models statistically. It is thus difficult to use the information encoded in small scales to test cosmological models or probe subtle features of the galaxy-halo connection. In this paper, we attempt to push halo modelling into the "accurate" regime with a fully numerical mock-based methodology and careful treatment of statistical and systematic errors. With our forward-modelling approach, we can incorporate clustering statistics beyond the traditional two-point statistics. We use this modelling methodology to test the standard ΛCDM + halo model against the clustering of SDSS DR7 galaxies. Specifically, we use the projected correlation function, group multiplicity function and galaxy number density as constraints. We find that while the model fits each statistic separately, it struggles to fit them simultaneously. Adding group statistics leads to a more stringent test of the model and significantly tighter constraints on model parameters. We explore the impact of varying the adopted halo definition and cosmological model and find that changing the cosmology makes a significant difference. The most successful model we tried (Planck cosmology with Mvir halos) matches the clustering of low luminosity galaxies, but exhibits a 2.3σ tension with the clustering of luminous galaxies, thus providing evidence that the "standard" halo model needs to be extended. This work opens the door to adding interesting freedom to the halo model and including additional clustering statistics as constraints.

  11. Unsteady free surface flow in porous media: One-dimensional model equations including vertical effects and seepage face

    NASA Astrophysics Data System (ADS)

    Di Nucci, Carmine

    2018-05-01

    This note examines the two-dimensional unsteady isothermal free surface flow of an incompressible fluid in a non-deformable, homogeneous, isotropic, and saturated porous medium (with zero recharge and neglecting capillary effects). Coupling a Boussinesq-type model for nonlinear water waves with Darcy's law, the two-dimensional flow problem is solved using one-dimensional model equations including vertical effects and seepage face. In order to take into account the seepage face development, the system equations (given by the continuity and momentum equations) are completed by an integral relation (deduced from the Cauchy theorem). After testing the model against data sets available in the literature, some numerical simulations, concerning the unsteady flow through a rectangular dam (with an impermeable horizontal bottom), are presented and discussed.

  12. Nonlinear storage models of unconfined flow through a shallow aquifer on an inclined base and their quasi-steady flow application

    NASA Astrophysics Data System (ADS)

    Varvaris, Ioannis; Gravanis, Elias; Koussis, Antonis; Akylas, Evangelos

    2013-04-01

    Hillslope processes involving flow through an inclined shallow aquifer range from subsurface stormflow to stream base flow (drought flow, or groundwater recession flow). In the case of recharge, the infiltrating water moves vertically as unsaturated flow until it reaches the saturated groundwater, where the flow is approximately parallel to the base of the aquifer. Boussinesq used the Dupuit-Forchheimer (D-F) hydraulic theory to formulate unconfined groundwater flow through a soil layer resting on an impervious inclined bed, deriving a nonlinear equation for the flow rate that consists of a linear gravity-driven component and a quadratic pressure-gradient component. Inserting that flow rate equation into the differential storage balance equation (volume conservation) Boussinesq obtained a nonlinear second-order partial differential equation for the depth. So far however, only few special solutions have been advanced for that governing equation. The nonlinearity of the equation of Boussinesq is the major obstacle to deriving a general analytical solution for the depth profile of unconfined flow on a sloping base with recharge (from which the discharges could be then determined). Henderson and Wooding (1964) were able to obtain an exact analytical solution for steady unconfined flow on a sloping base, with recharge, and their work deserves special note in the realm of solutions of the nonlinear equation of Boussinesq. However, the absence of a general solution for the transient case, which is of practical interest to hydrologists, has been the motivation for developing approximate solutions of the non-linear equation of Boussinesq. In this work, we derive the aquifer storage function by integrating analytically over the aquifer base the depth profiles resulting from the complete nonlinear Boussinesq equation for steady flow. This storage function consists of a linear and a nonlinear outflow-dependent term. Then, we use this physics-based storage function in the

  13. Numerical modeling of underground storage system for natural gas

    NASA Astrophysics Data System (ADS)

    Ding, J.; Wang, S.

    2017-12-01

    Natural gas is an important type of base-load energy, and its supply needs to be adjusted according to different demands in different seasons. For example, since natural gas is increasingly used to replace coal for winter heating, the demand for natural gas in winter is much higher than that in other seasons. As storage systems are the essential tools for balancing seasonal supply and demand, the design and simulation of natural gas storage systems form an important research direction. In this study, a large-scale underground storage system for natural gas is simulated based on theoretical analysis and finite element modeling.It is proven that the problem of axi-symmetric Darcy porous flow of ideal gas is governed by the Boussinesq equation. In terms of the exact solution to the Boussinesq equation, the basic operating characteristics of the underground storage system is analyzed, and it is demonstrated that the propagation distance of the pore pressure is proportional to the 1/4 power of the mass flow rate and to the 1/2 power of the propagation time. This quantitative relationship can be used to guide the overall design of natural gas underground storage systems.In order to fully capture the two-way coupling between pore pressure and elastic matrix deformation, a poro-elastic finite element model for natural gas storage is developed. Based on the numerical model, the dynamic processes of gas injection, storage and extraction are simulated, and the corresponding time-dependent surface deformations are obtained. The modeling results not only provide a theoretical basis for real-time monitoring for the operating status of the underground storage system through surface deformation measurements, but also demonstrate that a year-round balance can be achieved through periodic gas injection and extraction.This work is supported by the CAS "100 talents" Program and the National Natural Science Foundation of China (41371090).

  14. Accurate modeling of high-repetition rate ultrashort pulse amplification in optical fibers

    PubMed Central

    Lindberg, Robert; Zeil, Peter; Malmström, Mikael; Laurell, Fredrik; Pasiskevicius, Valdas

    2016-01-01

    A numerical model for amplification of ultrashort pulses with high repetition rates in fiber amplifiers is presented. The pulse propagation is modeled by jointly solving the steady-state rate equations and the generalized nonlinear Schrödinger equation, which allows accurate treatment of nonlinear and dispersive effects whilst considering arbitrary spatial and spectral gain dependencies. Comparison of data acquired by using the developed model and experimental results prove to be in good agreement. PMID:27713496

  15. Global Regularity for Several Incompressible Fluid Models with Partial Dissipation

    NASA Astrophysics Data System (ADS)

    Wu, Jiahong; Xu, Xiaojing; Ye, Zhuan

    2017-09-01

    This paper examines the global regularity problem on several 2D incompressible fluid models with partial dissipation. They are the surface quasi-geostrophic (SQG) equation, the 2D Euler equation and the 2D Boussinesq equations. These are well-known models in fluid mechanics and geophysics. The fundamental issue of whether or not they are globally well-posed has attracted enormous attention. The corresponding models with partial dissipation may arise in physical circumstances when the dissipation varies in different directions. We show that the SQG equation with either horizontal or vertical dissipation always has global solutions. This is in sharp contrast with the inviscid SQG equation for which the global regularity problem remains outstandingly open. Although the 2D Euler is globally well-posed for sufficiently smooth data, the associated equations with partial dissipation no longer conserve the vorticity and the global regularity is not trivial. We are able to prove the global regularity for two partially dissipated Euler equations. Several global bounds are also obtained for a partially dissipated Boussinesq system.

  16. Accurate modeling and evaluation of microstructures in complex materials

    NASA Astrophysics Data System (ADS)

    Tahmasebi, Pejman

    2018-02-01

    Accurate characterization of heterogeneous materials is of great importance for different fields of science and engineering. Such a goal can be achieved through imaging. Acquiring three- or two-dimensional images under different conditions is not, however, always plausible. On the other hand, accurate characterization of complex and multiphase materials requires various digital images (I) under different conditions. An ensemble method is presented that can take one single (or a set of) I(s) and stochastically produce several similar models of the given disordered material. The method is based on a successive calculating of a conditional probability by which the initial stochastic models are produced. Then, a graph formulation is utilized for removing unrealistic structures. A distance transform function for the Is with highly connected microstructure and long-range features is considered which results in a new I that is more informative. Reproduction of the I is also considered through a histogram matching approach in an iterative framework. Such an iterative algorithm avoids reproduction of unrealistic structures. Furthermore, a multiscale approach, based on pyramid representation of the large Is, is presented that can produce materials with millions of pixels in a matter of seconds. Finally, the nonstationary systems—those for which the distribution of data varies spatially—are studied using two different methods. The method is tested on several complex and large examples of microstructures. The produced results are all in excellent agreement with the utilized Is and the similarities are quantified using various correlation functions.

  17. Towards accurate modelling of galaxy clustering on small scales: testing the standard ΛCDM + halo model

    NASA Astrophysics Data System (ADS)

    Sinha, Manodeep; Berlind, Andreas A.; McBride, Cameron K.; Scoccimarro, Roman; Piscionere, Jennifer A.; Wibking, Benjamin D.

    2018-07-01

    Interpreting the small-scale clustering of galaxies with halo models can elucidate the connection between galaxies and dark matter haloes. Unfortunately, the modelling is typically not sufficiently accurate for ruling out models statistically. It is thus difficult to use the information encoded in small scales to test cosmological models or probe subtle features of the galaxy-halo connection. In this paper, we attempt to push halo modelling into the `accurate' regime with a fully numerical mock-based methodology and careful treatment of statistical and systematic errors. With our forward-modelling approach, we can incorporate clustering statistics beyond the traditional two-point statistics. We use this modelling methodology to test the standard Λ cold dark matter (ΛCDM) + halo model against the clustering of Sloan Digital Sky Survey (SDSS) seventh data release (DR7) galaxies. Specifically, we use the projected correlation function, group multiplicity function, and galaxy number density as constraints. We find that while the model fits each statistic separately, it struggles to fit them simultaneously. Adding group statistics leads to a more stringent test of the model and significantly tighter constraints on model parameters. We explore the impact of varying the adopted halo definition and cosmological model and find that changing the cosmology makes a significant difference. The most successful model we tried (Planck cosmology with Mvir haloes) matches the clustering of low-luminosity galaxies, but exhibits a 2.3σ tension with the clustering of luminous galaxies, thus providing evidence that the `standard' halo model needs to be extended. This work opens the door to adding interesting freedom to the halo model and including additional clustering statistics as constraints.

  18. A multiscale red blood cell model with accurate mechanics, rheology, and dynamics.

    PubMed

    Fedosov, Dmitry A; Caswell, Bruce; Karniadakis, George Em

    2010-05-19

    Red blood cells (RBCs) have highly deformable viscoelastic membranes exhibiting complex rheological response and rich hydrodynamic behavior governed by special elastic and bending properties and by the external/internal fluid and membrane viscosities. We present a multiscale RBC model that is able to predict RBC mechanics, rheology, and dynamics in agreement with experiments. Based on an analytic theory, the modeled membrane properties can be uniquely related to the experimentally established RBC macroscopic properties without any adjustment of parameters. The RBC linear and nonlinear elastic deformations match those obtained in optical-tweezers experiments. The rheological properties of the membrane are compared with those obtained in optical magnetic twisting cytometry, membrane thermal fluctuations, and creep followed by cell recovery. The dynamics of RBCs in shear and Poiseuille flows is tested against experiments and theoretical predictions, and the applicability of the latter is discussed. Our findings clearly indicate that a purely elastic model for the membrane cannot accurately represent the RBC's rheological properties and its dynamics, and therefore accurate modeling of a viscoelastic membrane is necessary. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  19. Waves at Navigation Structures

    DTIC Science & Technology

    2014-10-27

    upgrades the Coastal Modeling System’s (CMS) wave model CMS-Wave, a phase-averaged spectral wave model, and BOUSS-2D, a Boussinesq -type nonlinear wave...nearshore wave processes in practical applications. These capabilities facilitate optimization of innovative infrastructure for navigation systems to...navigation systems . The advanced models develop probabilistic engineering design estimates for rehabilitation of coastal structures to evaluate the

  20. Accurate Energy Consumption Modeling of IEEE 802.15.4e TSCH Using Dual-BandOpenMote Hardware.

    PubMed

    Daneels, Glenn; Municio, Esteban; Van de Velde, Bruno; Ergeerts, Glenn; Weyn, Maarten; Latré, Steven; Famaey, Jeroen

    2018-02-02

    The Time-Slotted Channel Hopping (TSCH) mode of the IEEE 802.15.4e amendment aims to improve reliability and energy efficiency in industrial and other challenging Internet-of-Things (IoT) environments. This paper presents an accurate and up-to-date energy consumption model for devices using this IEEE 802.15.4e TSCH mode. The model identifies all network-related CPU and radio state changes, thus providing a precise representation of the device behavior and an accurate prediction of its energy consumption. Moreover, energy measurements were performed with a dual-band OpenMote device, running the OpenWSN firmware. This allows the model to be used for devices using 2.4 GHz, as well as 868 MHz. Using these measurements, several network simulations were conducted to observe the TSCH energy consumption effects in end-to-end communication for both frequency bands. Experimental verification of the model shows that it accurately models the consumption for all possible packet sizes and that the calculated consumption on average differs less than 3% from the measured consumption. This deviation includes measurement inaccuracies and the variations of the guard time. As such, the proposed model is very suitable for accurate energy consumption modeling of TSCH networks.

  1. Accurate Energy Consumption Modeling of IEEE 802.15.4e TSCH Using Dual-BandOpenMote Hardware

    PubMed Central

    Municio, Esteban; Van de Velde, Bruno; Latré, Steven

    2018-01-01

    The Time-Slotted Channel Hopping (TSCH) mode of the IEEE 802.15.4e amendment aims to improve reliability and energy efficiency in industrial and other challenging Internet-of-Things (IoT) environments. This paper presents an accurate and up-to-date energy consumption model for devices using this IEEE 802.15.4e TSCH mode. The model identifies all network-related CPU and radio state changes, thus providing a precise representation of the device behavior and an accurate prediction of its energy consumption. Moreover, energy measurements were performed with a dual-band OpenMote device, running the OpenWSN firmware. This allows the model to be used for devices using 2.4 GHz, as well as 868 MHz. Using these measurements, several network simulations were conducted to observe the TSCH energy consumption effects in end-to-end communication for both frequency bands. Experimental verification of the model shows that it accurately models the consumption for all possible packet sizes and that the calculated consumption on average differs less than 3% from the measured consumption. This deviation includes measurement inaccuracies and the variations of the guard time. As such, the proposed model is very suitable for accurate energy consumption modeling of TSCH networks. PMID:29393900

  2. Accurate prediction of bacterial type IV secreted effectors using amino acid composition and PSSM profiles.

    PubMed

    Zou, Lingyun; Nan, Chonghan; Hu, Fuquan

    2013-12-15

    Various human pathogens secret effector proteins into hosts cells via the type IV secretion system (T4SS). These proteins play important roles in the interaction between bacteria and hosts. Computational methods for T4SS effector prediction have been developed for screening experimental targets in several isolated bacterial species; however, widely applicable prediction approaches are still unavailable In this work, four types of distinctive features, namely, amino acid composition, dipeptide composition, .position-specific scoring matrix composition and auto covariance transformation of position-specific scoring matrix, were calculated from primary sequences. A classifier, T4EffPred, was developed using the support vector machine with these features and their different combinations for effector prediction. Various theoretical tests were performed in a newly established dataset, and the results were measured with four indexes. We demonstrated that T4EffPred can discriminate IVA and IVB effectors in benchmark datasets with positive rates of 76.7% and 89.7%, respectively. The overall accuracy of 95.9% shows that the present method is accurate for distinguishing the T4SS effector in unidentified sequences. A classifier ensemble was designed to synthesize all single classifiers. Notable performance improvement was observed using this ensemble system in benchmark tests. To demonstrate the model's application, a genome-scale prediction of effectors was performed in Bartonella henselae, an important zoonotic pathogen. A number of putative candidates were distinguished. A web server implementing the prediction method and the source code are both available at http://bioinfo.tmmu.edu.cn/T4EffPred.

  3. Simple Mathematical Models Do Not Accurately Predict Early SIV Dynamics

    PubMed Central

    Noecker, Cecilia; Schaefer, Krista; Zaccheo, Kelly; Yang, Yiding; Day, Judy; Ganusov, Vitaly V.

    2015-01-01

    Upon infection of a new host, human immunodeficiency virus (HIV) replicates in the mucosal tissues and is generally undetectable in circulation for 1–2 weeks post-infection. Several interventions against HIV including vaccines and antiretroviral prophylaxis target virus replication at this earliest stage of infection. Mathematical models have been used to understand how HIV spreads from mucosal tissues systemically and what impact vaccination and/or antiretroviral prophylaxis has on viral eradication. Because predictions of such models have been rarely compared to experimental data, it remains unclear which processes included in these models are critical for predicting early HIV dynamics. Here we modified the “standard” mathematical model of HIV infection to include two populations of infected cells: cells that are actively producing the virus and cells that are transitioning into virus production mode. We evaluated the effects of several poorly known parameters on infection outcomes in this model and compared model predictions to experimental data on infection of non-human primates with variable doses of simian immunodifficiency virus (SIV). First, we found that the mode of virus production by infected cells (budding vs. bursting) has a minimal impact on the early virus dynamics for a wide range of model parameters, as long as the parameters are constrained to provide the observed rate of SIV load increase in the blood of infected animals. Interestingly and in contrast with previous results, we found that the bursting mode of virus production generally results in a higher probability of viral extinction than the budding mode of virus production. Second, this mathematical model was not able to accurately describe the change in experimentally determined probability of host infection with increasing viral doses. Third and finally, the model was also unable to accurately explain the decline in the time to virus detection with increasing viral dose. These results

  4. Accurate Cold-Test Model of Helical TWT Slow-Wave Circuits

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Dayton, James A., Jr.

    1997-01-01

    Recently, a method has been established to accurately calculate cold-test data for helical slow-wave structures using the three-dimensional electromagnetic computer code, MAFIA. Cold-test parameters have been calculated for several helical traveling-wave tube (TWT) slow-wave circuits possessing various support rod configurations, and results are presented here showing excellent agreement with experiment. The helical models include tape thickness, dielectric support shapes and material properties consistent with the actual circuits. The cold-test data from this helical model can be used as input into large-signal helical TWT interaction codes making it possible, for the first time, to design a complete TWT via computer simulation.

  5. Multi-fidelity Gaussian process regression for prediction of random fields

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parussini, L.; Venturi, D., E-mail: venturi@ucsc.edu; Perdikaris, P.

    We propose a new multi-fidelity Gaussian process regression (GPR) approach for prediction of random fields based on observations of surrogate models or hierarchies of surrogate models. Our method builds upon recent work on recursive Bayesian techniques, in particular recursive co-kriging, and extends it to vector-valued fields and various types of covariances, including separable and non-separable ones. The framework we propose is general and can be used to perform uncertainty propagation and quantification in model-based simulations, multi-fidelity data fusion, and surrogate-based optimization. We demonstrate the effectiveness of the proposed recursive GPR techniques through various examples. Specifically, we study the stochastic Burgersmore » equation and the stochastic Oberbeck–Boussinesq equations describing natural convection within a square enclosure. In both cases we find that the standard deviation of the Gaussian predictors as well as the absolute errors relative to benchmark stochastic solutions are very small, suggesting that the proposed multi-fidelity GPR approaches can yield highly accurate results.« less

  6. Extracting TSK-type Neuro-Fuzzy model using the Hunting search algorithm

    NASA Astrophysics Data System (ADS)

    Bouzaida, Sana; Sakly, Anis; M'Sahli, Faouzi

    2014-01-01

    This paper proposes a Takagi-Sugeno-Kang (TSK) type Neuro-Fuzzy model tuned by a novel metaheuristic optimization algorithm called Hunting Search (HuS). The HuS algorithm is derived based on a model of group hunting of animals such as lions, wolves, and dolphins when looking for a prey. In this study, the structure and parameters of the fuzzy model are encoded into a particle. Thus, the optimal structure and parameters are achieved simultaneously. The proposed method was demonstrated through modeling and control problems, and the results have been compared with other optimization techniques. The comparisons indicate that the proposed method represents a powerful search approach and an effective optimization technique as it can extract the accurate TSK fuzzy model with an appropriate number of rules.

  7. Generating Facial Expressions Using an Anatomically Accurate Biomechanical Model.

    PubMed

    Wu, Tim; Hung, Alice; Mithraratne, Kumar

    2014-11-01

    This paper presents a computational framework for modelling the biomechanics of human facial expressions. A detailed high-order (Cubic-Hermite) finite element model of the human head was constructed using anatomical data segmented from magnetic resonance images. The model includes a superficial soft-tissue continuum consisting of skin, the subcutaneous layer and the superficial Musculo-Aponeurotic system. Embedded within this continuum mesh, are 20 pairs of facial muscles which drive facial expressions. These muscles were treated as transversely-isotropic and their anatomical geometries and fibre orientations were accurately depicted. In order to capture the relative composition of muscles and fat, material heterogeneity was also introduced into the model. Complex contact interactions between the lips, eyelids, and between superficial soft tissue continuum and deep rigid skeletal bones were also computed. In addition, this paper investigates the impact of incorporating material heterogeneity and contact interactions, which are often neglected in similar studies. Four facial expressions were simulated using the developed model and the results were compared with surface data obtained from a 3D structured-light scanner. Predicted expressions showed good agreement with the experimental data.

  8. Memory conformity affects inaccurate memories more than accurate memories.

    PubMed

    Wright, Daniel B; Villalba, Daniella K

    2012-01-01

    After controlling for initial confidence, inaccurate memories were shown to be more easily distorted than accurate memories. In two experiments groups of participants viewed 50 stimuli and were then presented with these stimuli plus 50 fillers. During this test phase participants reported their confidence that each stimulus was originally shown. This was followed by computer-generated responses from a bogus participant. After being exposed to this response participants again rated the confidence of their memory. The computer-generated responses systematically distorted participants' responses. Memory distortion depended on initial memory confidence, with uncertain memories being more malleable than confident memories. This effect was moderated by whether the participant's memory was initially accurate or inaccurate. Inaccurate memories were more malleable than accurate memories. The data were consistent with a model describing two types of memory (i.e., recollective and non-recollective memories), which differ in how susceptible these memories are to memory distortion.

  9. Numerically accurate computational techniques for optimal estimator analyses of multi-parameter models

    NASA Astrophysics Data System (ADS)

    Berger, Lukas; Kleinheinz, Konstantin; Attili, Antonio; Bisetti, Fabrizio; Pitsch, Heinz; Mueller, Michael E.

    2018-05-01

    Modelling unclosed terms in partial differential equations typically involves two steps: First, a set of known quantities needs to be specified as input parameters for a model, and second, a specific functional form needs to be defined to model the unclosed terms by the input parameters. Both steps involve a certain modelling error, with the former known as the irreducible error and the latter referred to as the functional error. Typically, only the total modelling error, which is the sum of functional and irreducible error, is assessed, but the concept of the optimal estimator enables the separate analysis of the total and the irreducible errors, yielding a systematic modelling error decomposition. In this work, attention is paid to the techniques themselves required for the practical computation of irreducible errors. Typically, histograms are used for optimal estimator analyses, but this technique is found to add a non-negligible spurious contribution to the irreducible error if models with multiple input parameters are assessed. Thus, the error decomposition of an optimal estimator analysis becomes inaccurate, and misleading conclusions concerning modelling errors may be drawn. In this work, numerically accurate techniques for optimal estimator analyses are identified and a suitable evaluation of irreducible errors is presented. Four different computational techniques are considered: a histogram technique, artificial neural networks, multivariate adaptive regression splines, and an additive model based on a kernel method. For multiple input parameter models, only artificial neural networks and multivariate adaptive regression splines are found to yield satisfactorily accurate results. Beyond a certain number of input parameters, the assessment of models in an optimal estimator analysis even becomes practically infeasible if histograms are used. The optimal estimator analysis in this paper is applied to modelling the filtered soot intermittency in large eddy

  10. Accurate and scalable social recommendation using mixed-membership stochastic block models.

    PubMed

    Godoy-Lorite, Antonia; Guimerà, Roger; Moore, Cristopher; Sales-Pardo, Marta

    2016-12-13

    With increasing amounts of information available, modeling and predicting user preferences-for books or articles, for example-are becoming more important. We present a collaborative filtering model, with an associated scalable algorithm, that makes accurate predictions of users' ratings. Like previous approaches, we assume that there are groups of users and of items and that the rating a user gives an item is determined by their respective group memberships. However, we allow each user and each item to belong simultaneously to mixtures of different groups and, unlike many popular approaches such as matrix factorization, we do not assume that users in each group prefer a single group of items. In particular, we do not assume that ratings depend linearly on a measure of similarity, but allow probability distributions of ratings to depend freely on the user's and item's groups. The resulting overlapping groups and predicted ratings can be inferred with an expectation-maximization algorithm whose running time scales linearly with the number of observed ratings. Our approach enables us to predict user preferences in large datasets and is considerably more accurate than the current algorithms for such large datasets.

  11. Accurate and scalable social recommendation using mixed-membership stochastic block models

    PubMed Central

    Godoy-Lorite, Antonia; Moore, Cristopher

    2016-01-01

    With increasing amounts of information available, modeling and predicting user preferences—for books or articles, for example—are becoming more important. We present a collaborative filtering model, with an associated scalable algorithm, that makes accurate predictions of users’ ratings. Like previous approaches, we assume that there are groups of users and of items and that the rating a user gives an item is determined by their respective group memberships. However, we allow each user and each item to belong simultaneously to mixtures of different groups and, unlike many popular approaches such as matrix factorization, we do not assume that users in each group prefer a single group of items. In particular, we do not assume that ratings depend linearly on a measure of similarity, but allow probability distributions of ratings to depend freely on the user’s and item’s groups. The resulting overlapping groups and predicted ratings can be inferred with an expectation-maximization algorithm whose running time scales linearly with the number of observed ratings. Our approach enables us to predict user preferences in large datasets and is considerably more accurate than the current algorithms for such large datasets. PMID:27911773

  12. Introduction to Phase-Resolving Wave Modeling with FUNWAVE

    DTIC Science & Technology

    2015-07-01

    Boussinesq wave models have become a useful tool for modeling surface wave transformation from deep water to the swash zone, as well as wave-induced...overlapping area of ghost cells, three rows deep , as required by the fourth-order MUSCL-TVD scheme. The MPI with nonblocking communication was used to...implemented ERDC/CHL CHETN-I-87 July 2015 12 SPONGE LAYER SPONGE_ON Sponge_west_width Sponge_east_width Sponge_south_width

  13. Dynamic sensing model for accurate delectability of environmental phenomena using event wireless sensor network

    NASA Astrophysics Data System (ADS)

    Missif, Lial Raja; Kadhum, Mohammad M.

    2017-09-01

    Wireless Sensor Network (WSN) has been widely used for monitoring where sensors are deployed to operate independently to sense abnormal phenomena. Most of the proposed environmental monitoring systems are designed based on a predetermined sensing range which does not reflect the sensor reliability, event characteristics, and the environment conditions. Measuring of the capability of a sensor node to accurately detect an event within a sensing field is of great important for monitoring applications. This paper presents an efficient mechanism for even detection based on probabilistic sensing model. Different models have been presented theoretically in this paper to examine their adaptability and applicability to the real environment applications. The numerical results of the experimental evaluation have showed that the probabilistic sensing model provides accurate observation and delectability of an event, and it can be utilized for different environment scenarios.

  14. Accurate and reproducible functional maps in 127 human cell types via 2D genome segmentation

    PubMed Central

    Hardison, Ross C.

    2017-01-01

    Abstract The Roadmap Epigenomics Consortium has published whole-genome functional annotation maps in 127 human cell types by integrating data from studies of multiple epigenetic marks. These maps have been widely used for studying gene regulation in cell type-specific contexts and predicting the functional impact of DNA mutations on disease. Here, we present a new map of functional elements produced by applying a method called IDEAS on the same data. The method has several unique advantages and outperforms existing methods, including that used by the Roadmap Epigenomics Consortium. Using five categories of independent experimental datasets, we compared the IDEAS and Roadmap Epigenomics maps. While the overall concordance between the two maps is high, the maps differ substantially in the prediction details and in their consistency of annotation of a given genomic position across cell types. The annotation from IDEAS is uniformly more accurate than the Roadmap Epigenomics annotation and the improvement is substantial based on several criteria. We further introduce a pipeline that improves the reproducibility of functional annotation maps. Thus, we provide a high-quality map of candidate functional regions across 127 human cell types and compare the quality of different annotation methods in order to facilitate biomedical research in epigenomics. PMID:28973456

  15. Getting a Picture that Is Both Accurate and Stable: Situation Models and Epistemic Validation

    ERIC Educational Resources Information Center

    Schroeder, Sascha; Richter, Tobias; Hoever, Inga

    2008-01-01

    Text comprehension entails the construction of a situation model that prepares individuals for situated action. In order to meet this function, situation model representations are required to be both accurate and stable. We propose a framework according to which comprehenders rely on epistemic validation to prevent inaccurate information from…

  16. Accurate Treatment of Collision and Water-Delivery in Models of Terrestrial Planet Formation

    NASA Astrophysics Data System (ADS)

    Haghighipour, N.; Maindl, T. I.; Schaefer, C. M.; Wandel, O.

    2017-08-01

    We have developed a comprehensive approach in simulating collisions and growth of embryos to terrestrial planets where we use a combination of SPH and N-body codes to model collisions and the transfer of water and chemical compounds accurately.

  17. Modeling of capacitor charging dynamics in an energy harvesting system considering accurate electromechanical coupling effects

    NASA Astrophysics Data System (ADS)

    Bagheri, Shahriar; Wu, Nan; Filizadeh, Shaahin

    2018-06-01

    This paper presents an iterative numerical method that accurately models an energy harvesting system charging a capacitor with piezoelectric patches. The constitutive relations of piezoelectric materials connected with an external charging circuit with a diode bridge and capacitors lead to the electromechanical coupling effect and the difficulty of deriving accurate transient mechanical response, as well as the charging progress. The proposed model is built upon the Euler-Bernoulli beam theory and takes into account the electromechanical coupling effects as well as the dynamic process of charging an external storage capacitor. The model is validated through experimental tests on a cantilever beam coated with piezoelectric patches. Several parametric studies are performed and the functionality of the model is verified. The efficiency of power harvesting system can be predicted and tuned considering variations in different design parameters. Such a model can be utilized to design robust and optimal energy harvesting system.

  18. Obtaining Accurate Probabilities Using Classifier Calibration

    ERIC Educational Resources Information Center

    Pakdaman Naeini, Mahdi

    2016-01-01

    Learning probabilistic classification and prediction models that generate accurate probabilities is essential in many prediction and decision-making tasks in machine learning and data mining. One way to achieve this goal is to post-process the output of classification models to obtain more accurate probabilities. These post-processing methods are…

  19. Validation of an Accurate Three-Dimensional Helical Slow-Wave Circuit Model

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.

    1997-01-01

    The helical slow-wave circuit embodies a helical coil of rectangular tape supported in a metal barrel by dielectric support rods. Although the helix slow-wave circuit remains the mainstay of the traveling-wave tube (TWT) industry because of its exceptionally wide bandwidth, a full helical circuit, without significant dimensional approximations, has not been successfully modeled until now. Numerous attempts have been made to analyze the helical slow-wave circuit so that the performance could be accurately predicted without actually building it, but because of its complex geometry, many geometrical approximations became necessary rendering the previous models inaccurate. In the course of this research it has been demonstrated that using the simulation code, MAFIA, the helical structure can be modeled with actual tape width and thickness, dielectric support rod geometry and materials. To demonstrate the accuracy of the MAFIA model, the cold-test parameters including dispersion, on-axis interaction impedance and attenuation have been calculated for several helical TWT slow-wave circuits with a variety of support rod geometries including rectangular and T-shaped rods, as well as various support rod materials including isotropic, anisotropic and partially metal coated dielectrics. Compared with experimentally measured results, the agreement is excellent. With the accuracy of the MAFIA helical model validated, the code was used to investigate several conventional geometric approximations in an attempt to obtain the most computationally efficient model. Several simplifications were made to a standard model including replacing the helical tape with filaments, and replacing rectangular support rods with shapes conforming to the cylindrical coordinate system with effective permittivity. The approximate models are compared with the standard model in terms of cold-test characteristics and computational time. The model was also used to determine the sensitivity of various

  20. PconsD: ultra rapid, accurate model quality assessment for protein structure prediction.

    PubMed

    Skwark, Marcin J; Elofsson, Arne

    2013-07-15

    Clustering methods are often needed for accurately assessing the quality of modeled protein structures. Recent blind evaluation of quality assessment methods in CASP10 showed that there is little difference between many different methods as far as ranking models and selecting best model are concerned. When comparing many models, the computational cost of the model comparison can become significant. Here, we present PconsD, a fast, stream-computing method for distance-driven model quality assessment that runs on consumer hardware. PconsD is at least one order of magnitude faster than other methods of comparable accuracy. The source code for PconsD is freely available at http://d.pcons.net/. Supplementary benchmarking data are also available there. arne@bioinfo.se Supplementary data are available at Bioinformatics online.

  1. Analytic model for a weakly dissipative shallow-water undular bore.

    PubMed

    El, G A; Grimshaw, R H J; Kamchatnov, A M

    2005-09-01

    We use the integrable Kaup-Boussinesq shallow water system, modified by a small viscous term, to model the formation of an undular bore with a steady profile. The description is made in terms of the corresponding integrable Whitham system, also appropriately modified by viscosity. This is derived in Riemann variables using a modified finite-gap integration technique for the Ablowitz-Kaup-Newell-Segur (AKNS) scheme. The Whitham system is then reduced to a simple first-order differential equation which is integrated numerically to obtain an asymptotic profile of the undular bore, with the local oscillatory structure described by the periodic solution of the unperturbed Kaup-Boussinesq system. This solution of the Whitham equations is shown to be consistent with certain jump conditions following directly from conservation laws for the original system. A comparison is made with the recently studied dissipationless case for the same system, where the undular bore is unsteady.

  2. Accurately modeling Gaussian beam propagation in the context of Monte Carlo techniques

    NASA Astrophysics Data System (ADS)

    Hokr, Brett H.; Winblad, Aidan; Bixler, Joel N.; Elpers, Gabriel; Zollars, Byron; Scully, Marlan O.; Yakovlev, Vladislav V.; Thomas, Robert J.

    2016-03-01

    Monte Carlo simulations are widely considered to be the gold standard for studying the propagation of light in turbid media. However, traditional Monte Carlo methods fail to account for diffraction because they treat light as a particle. This results in converging beams focusing to a point instead of a diffraction limited spot, greatly effecting the accuracy of Monte Carlo simulations near the focal plane. Here, we present a technique capable of simulating a focusing beam in accordance to the rules of Gaussian optics, resulting in a diffraction limited focal spot. This technique can be easily implemented into any traditional Monte Carlo simulation allowing existing models to be converted to include accurate focusing geometries with minimal effort. We will present results for a focusing beam in a layered tissue model, demonstrating that for different scenarios the region of highest intensity, thus the greatest heating, can change from the surface to the focus. The ability to simulate accurate focusing geometries will greatly enhance the usefulness of Monte Carlo for countless applications, including studying laser tissue interactions in medical applications and light propagation through turbid media.

  3. Bottom-up coarse-grained models that accurately describe the structure, pressure, and compressibility of molecular liquids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dunn, Nicholas J. H.; Noid, W. G., E-mail: wnoid@chem.psu.edu

    2015-12-28

    The present work investigates the capability of bottom-up coarse-graining (CG) methods for accurately modeling both structural and thermodynamic properties of all-atom (AA) models for molecular liquids. In particular, we consider 1, 2, and 3-site CG models for heptane, as well as 1 and 3-site CG models for toluene. For each model, we employ the multiscale coarse-graining method to determine interaction potentials that optimally approximate the configuration dependence of the many-body potential of mean force (PMF). We employ a previously developed “pressure-matching” variational principle to determine a volume-dependent contribution to the potential, U{sub V}(V), that approximates the volume-dependence of the PMF.more » We demonstrate that the resulting CG models describe AA density fluctuations with qualitative, but not quantitative, accuracy. Accordingly, we develop a self-consistent approach for further optimizing U{sub V}, such that the CG models accurately reproduce the equilibrium density, compressibility, and average pressure of the AA models, although the CG models still significantly underestimate the atomic pressure fluctuations. Additionally, by comparing this array of models that accurately describe the structure and thermodynamic pressure of heptane and toluene at a range of different resolutions, we investigate the impact of bottom-up coarse-graining upon thermodynamic properties. In particular, we demonstrate that U{sub V} accounts for the reduced cohesion in the CG models. Finally, we observe that bottom-up coarse-graining introduces subtle correlations between the resolution, the cohesive energy density, and the “simplicity” of the model.« less

  4. Bayesian parameter estimation of a k-ε model for accurate jet-in-crossflow simulations

    DOE PAGES

    Ray, Jaideep; Lefantzi, Sophia; Arunajatesan, Srinivasan; ...

    2016-05-31

    Reynolds-averaged Navier–Stokes models are not very accurate for high-Reynolds-number compressible jet-in-crossflow interactions. The inaccuracy arises from the use of inappropriate model parameters and model-form errors in the Reynolds-averaged Navier–Stokes model. In this study, the hypothesis is pursued that Reynolds-averaged Navier–Stokes predictions can be significantly improved by using parameters inferred from experimental measurements of a supersonic jet interacting with a transonic crossflow.

  5. Generalization of the normal-exponential model: exploration of a more accurate parametrisation for the signal distribution on Illumina BeadArrays.

    PubMed

    Plancade, Sandra; Rozenholc, Yves; Lund, Eiliv

    2012-12-11

    Illumina BeadArray technology includes non specific negative control features that allow a precise estimation of the background noise. As an alternative to the background subtraction proposed in BeadStudio which leads to an important loss of information by generating negative values, a background correction method modeling the observed intensities as the sum of the exponentially distributed signal and normally distributed noise has been developed. Nevertheless, Wang and Ye (2012) display a kernel-based estimator of the signal distribution on Illumina BeadArrays and suggest that a gamma distribution would represent a better modeling of the signal density. Hence, the normal-exponential modeling may not be appropriate for Illumina data and background corrections derived from this model may lead to wrong estimation. We propose a more flexible modeling based on a gamma distributed signal and a normal distributed background noise and develop the associated background correction, implemented in the R-package NormalGamma. Our model proves to be markedly more accurate to model Illumina BeadArrays: on the one hand, it is shown on two types of Illumina BeadChips that this model offers a more correct fit of the observed intensities. On the other hand, the comparison of the operating characteristics of several background correction procedures on spike-in and on normal-gamma simulated data shows high similarities, reinforcing the validation of the normal-gamma modeling. The performance of the background corrections based on the normal-gamma and normal-exponential models are compared on two dilution data sets, through testing procedures which represent various experimental designs. Surprisingly, we observe that the implementation of a more accurate parametrisation in the model-based background correction does not increase the sensitivity. These results may be explained by the operating characteristics of the estimators: the normal-gamma background correction offers an improvement

  6. An Arrhenius-type viscosity function to model sintering using the Skorohod Olevsky viscous sintering model within a finite element code.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ewsuk, Kevin Gregory; Arguello, Jose Guadalupe, Jr.; Reiterer, Markus W.

    2006-02-01

    The ease and ability to predict sintering shrinkage and densification with the Skorohod-Olevsky viscous sintering (SOVS) model within a finite-element (FE) code have been improved with the use of an Arrhenius-type viscosity function. The need for a better viscosity function was identified by evaluating SOVS model predictions made using a previously published polynomial viscosity function. Predictions made using the original, polynomial viscosity function do not accurately reflect experimentally observed sintering behavior. To more easily and better predict sintering behavior using FE simulations, a thermally activated viscosity function based on creep theory was used with the SOVS model. In comparison withmore » the polynomial viscosity function, SOVS model predictions made using the Arrhenius-type viscosity function are more representative of experimentally observed viscosity and sintering behavior. Additionally, the effects of changes in heating rate on densification can easily be predicted with the Arrhenius-type viscosity function. Another attribute of the Arrhenius-type viscosity function is that it provides the potential to link different sintering models. For example, the apparent activation energy, Q, for densification used in the construction of the master sintering curve for a low-temperature cofire ceramic dielectric has been used as the apparent activation energy for material flow in the Arrhenius-type viscosity function to predict heating rate-dependent sintering behavior using the SOVS model.« less

  7. Accurate modeling of defects in graphene transport calculations

    NASA Astrophysics Data System (ADS)

    Linhart, Lukas; Burgdörfer, Joachim; Libisch, Florian

    2018-01-01

    We present an approach for embedding defect structures modeled by density functional theory into large-scale tight-binding simulations. We extract local tight-binding parameters for the vicinity of the defect site using Wannier functions. In the transition region between the bulk lattice and the defect the tight-binding parameters are continuously adjusted to approach the bulk limit far away from the defect. This embedding approach allows for an accurate high-level treatment of the defect orbitals using as many as ten nearest neighbors while keeping a small number of nearest neighbors in the bulk to render the overall computational cost reasonable. As an example of our approach, we consider an extended graphene lattice decorated with Stone-Wales defects, flower defects, double vacancies, or silicon substitutes. We predict distinct scattering patterns mirroring the defect symmetries and magnitude that should be experimentally accessible.

  8. Accurate Modelling of Surface Currents and Internal Tides in a Semi-enclosed Coastal Sea

    NASA Astrophysics Data System (ADS)

    Allen, S. E.; Soontiens, N. K.; Dunn, M. B. H.; Liu, J.; Olson, E.; Halverson, M. J.; Pawlowicz, R.

    2016-02-01

    The Strait of Georgia is a deep (400 m), strongly stratified, semi-enclosed coastal sea on the west coast of North America. We have configured a baroclinic model of the Strait of Georgia and surrounding coastal waters using the NEMO ocean community model. We run daily nowcasts and forecasts and publish our sea-surface results (including storm surge warnings) to the web (salishsea.eos.ubc.ca/storm-surge). Tides in the Strait of Georgia are mixed and large. The baroclinic model and previous barotropic models accurately represent tidal sea-level variations and depth mean currents. The baroclinic model reproduces accurately the diurnal but not the semi-diurnal baroclinic tidal currents. In the Southern Strait of Georgia, strong internal tidal currents at the semi-diurnal frequency are observed. Strong semi-diurnal tides are also produced in the model, but are almost 180 degrees out of phase with the observations. In the model, in the surface, the barotropic and baroclinic tides reinforce, whereas the observations show that at the surface the baroclinic tides oppose the barotropic. As such the surface currents are very poorly modelled. Here we will present evidence of the internal tidal field from observations. We will discuss the generation regions of the tides, the necessary modifications to the model required to correct the phase, the resulting baroclinic tides and the improvements in the surface currents.

  9. Wave turbulence in shallow water models.

    PubMed

    Clark di Leoni, P; Cobelli, P J; Mininni, P D

    2014-06-01

    We study wave turbulence in shallow water flows in numerical simulations using two different approximations: the shallow water model and the Boussinesq model with weak dispersion. The equations for both models were solved using periodic grids with up to 2048{2} points. In all simulations, the Froude number varies between 0.015 and 0.05, while the Reynolds number and level of dispersion are varied in a broader range to span different regimes. In all cases, most of the energy in the system remains in the waves, even after integrating the system for very long times. For shallow flows, nonlinear waves are nondispersive and the spectrum of potential energy is compatible with ∼k{-2} scaling. For deeper (Boussinesq) flows, the nonlinear dispersion relation as directly measured from the wave and frequency spectrum (calculated independently) shows signatures of dispersion, and the spectrum of potential energy is compatible with predictions of weak turbulence theory, ∼k{-4/3}. In this latter case, the nonlinear dispersion relation differs from the linear one and has two branches, which we explain with a simple qualitative argument. Finally, we study probability density functions of the surface height and find that in all cases the distributions are asymmetric. The probability density function can be approximated by a skewed normal distribution as well as by a Tayfun distribution.

  10. Accurate SHAPE-directed RNA secondary structure modeling, including pseudoknots.

    PubMed

    Hajdin, Christine E; Bellaousov, Stanislav; Huggins, Wayne; Leonard, Christopher W; Mathews, David H; Weeks, Kevin M

    2013-04-02

    A pseudoknot forms in an RNA when nucleotides in a loop pair with a region outside the helices that close the loop. Pseudoknots occur relatively rarely in RNA but are highly overrepresented in functionally critical motifs in large catalytic RNAs, in riboswitches, and in regulatory elements of viruses. Pseudoknots are usually excluded from RNA structure prediction algorithms. When included, these pairings are difficult to model accurately, especially in large RNAs, because allowing this structure dramatically increases the number of possible incorrect folds and because it is difficult to search the fold space for an optimal structure. We have developed a concise secondary structure modeling approach that combines SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) experimental chemical probing information and a simple, but robust, energy model for the entropic cost of single pseudoknot formation. Structures are predicted with iterative refinement, using a dynamic programming algorithm. This melded experimental and thermodynamic energy function predicted the secondary structures and the pseudoknots for a set of 21 challenging RNAs of known structure ranging in size from 34 to 530 nt. On average, 93% of known base pairs were predicted, and all pseudoknots in well-folded RNAs were identified.

  11. Accurate coarse-grained models for mixtures of colloids and linear polymers under good-solvent conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    D’Adamo, Giuseppe, E-mail: giuseppe.dadamo@sissa.it; Pelissetto, Andrea, E-mail: andrea.pelissetto@roma1.infn.it; Pierleoni, Carlo, E-mail: carlo.pierleoni@aquila.infn.it

    2014-12-28

    A coarse-graining strategy, previously developed for polymer solutions, is extended here to mixtures of linear polymers and hard-sphere colloids. In this approach, groups of monomers are mapped onto a single pseudoatom (a blob) and the effective blob-blob interactions are obtained by requiring the model to reproduce some large-scale structural properties in the zero-density limit. We show that an accurate parametrization of the polymer-colloid interactions is obtained by simply introducing pair potentials between blobs and colloids. For the coarse-grained (CG) model in which polymers are modelled as four-blob chains (tetramers), the pair potentials are determined by means of the iterative Boltzmannmore » inversion scheme, taking full-monomer (FM) pair correlation functions at zero-density as targets. For a larger number n of blobs, pair potentials are determined by using a simple transferability assumption based on the polymer self-similarity. We validate the model by comparing its predictions with full-monomer results for the interfacial properties of polymer solutions in the presence of a single colloid and for thermodynamic and structural properties in the homogeneous phase at finite polymer and colloid density. The tetramer model is quite accurate for q ≲ 1 (q=R{sup ^}{sub g}/R{sub c}, where R{sup ^}{sub g} is the zero-density polymer radius of gyration and R{sub c} is the colloid radius) and reasonably good also for q = 2. For q = 2, an accurate coarse-grained description is obtained by using the n = 10 blob model. We also compare our results with those obtained by using single-blob models with state-dependent potentials.« less

  12. A Simple and Accurate Model to Predict Responses to Multi-electrode Stimulation in the Retina

    PubMed Central

    Maturana, Matias I.; Apollo, Nicholas V.; Hadjinicolaou, Alex E.; Garrett, David J.; Cloherty, Shaun L.; Kameneva, Tatiana; Grayden, David B.; Ibbotson, Michael R.; Meffin, Hamish

    2016-01-01

    Implantable electrode arrays are widely used in therapeutic stimulation of the nervous system (e.g. cochlear, retinal, and cortical implants). Currently, most neural prostheses use serial stimulation (i.e. one electrode at a time) despite this severely limiting the repertoire of stimuli that can be applied. Methods to reliably predict the outcome of multi-electrode stimulation have not been available. Here, we demonstrate that a linear-nonlinear model accurately predicts neural responses to arbitrary patterns of stimulation using in vitro recordings from single retinal ganglion cells (RGCs) stimulated with a subretinal multi-electrode array. In the model, the stimulus is projected onto a low-dimensional subspace and then undergoes a nonlinear transformation to produce an estimate of spiking probability. The low-dimensional subspace is estimated using principal components analysis, which gives the neuron’s electrical receptive field (ERF), i.e. the electrodes to which the neuron is most sensitive. Our model suggests that stimulation proportional to the ERF yields a higher efficacy given a fixed amount of power when compared to equal amplitude stimulation on up to three electrodes. We find that the model captures the responses of all the cells recorded in the study, suggesting that it will generalize to most cell types in the retina. The model is computationally efficient to evaluate and, therefore, appropriate for future real-time applications including stimulation strategies that make use of recorded neural activity to improve the stimulation strategy. PMID:27035143

  13. Development of an Anatomically Accurate Finite Element Human Ocular Globe Model for Blast-Related Fluid-Structure Interaction Studies

    DTIC Science & Technology

    2017-02-01

    ARL-TR-7945 ● FEB 2017 US Army Research Laboratory Development of an Anatomically Accurate Finite Element Human Ocular Globe...ARL-TR-7945 ● FEB 2017 US Army Research Laboratory Development of an Anatomically Accurate Finite Element Human Ocular Globe Model... Finite Element Human Ocular Globe Model for Blast-Related Fluid-Structure Interaction Studies 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  14. Accurate, efficient, and (iso)geometrically flexible collocation methods for phase-field models

    NASA Astrophysics Data System (ADS)

    Gomez, Hector; Reali, Alessandro; Sangalli, Giancarlo

    2014-04-01

    We propose new collocation methods for phase-field models. Our algorithms are based on isogeometric analysis, a new technology that makes use of functions from computational geometry, such as, for example, Non-Uniform Rational B-Splines (NURBS). NURBS exhibit excellent approximability and controllable global smoothness, and can represent exactly most geometries encapsulated in Computer Aided Design (CAD) models. These attributes permitted us to derive accurate, efficient, and geometrically flexible collocation methods for phase-field models. The performance of our method is demonstrated by several numerical examples of phase separation modeled by the Cahn-Hilliard equation. We feel that our method successfully combines the geometrical flexibility of finite elements with the accuracy and simplicity of pseudo-spectral collocation methods, and is a viable alternative to classical collocation methods.

  15. Waves at Navigation Structures

    DTIC Science & Technology

    2015-10-30

    upgrades the Coastal Modeling System (CMS) wave models CMS-Wave, a phase- averaged spectral wave model, and BOUSS-2D, a Boussinesq type nonlinear wave...developing WaveNet and TideNet, two Web-based tool systems for wind and wave data access and processing, which provide critical data for USACE project...practical applications, resulting in optimization of navigation system to improve safety, reliability and operations with innovative infrastructures

  16. BEYOND ELLIPSE(S): ACCURATELY MODELING THE ISOPHOTAL STRUCTURE OF GALAXIES WITH ISOFIT AND CMODEL

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ciambur, B. C., E-mail: bciambur@swin.edu.au

    2015-09-10

    This work introduces a new fitting formalism for isophotes that enables more accurate modeling of galaxies with non-elliptical shapes, such as disk galaxies viewed edge-on or galaxies with X-shaped/peanut bulges. Within this scheme, the angular parameter that defines quasi-elliptical isophotes is transformed from the commonly used, but inappropriate, polar coordinate to the “eccentric anomaly.” This provides a superior description of deviations from ellipticity, better capturing the true isophotal shape. Furthermore, this makes it possible to accurately recover both the surface brightness profile, using the correct azimuthally averaged isophote, and the two-dimensional model of any galaxy: the hitherto ubiquitous, but artificial,more » cross-like features in residual images are completely removed. The formalism has been implemented into the Image Reduction and Analysis Facility tasks Ellipse and Bmodel to create the new tasks “Isofit,” and “Cmodel.” The new tools are demonstrated here with application to five galaxies, chosen to be representative case-studies for several areas where this technique makes it possible to gain new scientific insight. Specifically: properly quantifying boxy/disky isophotes via the fourth harmonic order in edge-on galaxies, quantifying X-shaped/peanut bulges, higher-order Fourier moments for modeling bars in disks, and complex isophote shapes. Higher order (n > 4) harmonics now become meaningful and may correlate with structural properties, as boxyness/diskyness is known to do. This work also illustrates how the accurate construction, and subtraction, of a model from a galaxy image facilitates the identification and recovery of over-lapping sources such as globular clusters and the optical counterparts of X-ray sources.« less

  17. Production of Accurate Skeletal Models of Domestic Animals Using Three-Dimensional Scanning and Printing Technology

    ERIC Educational Resources Information Center

    Li, Fangzheng; Liu, Chunying; Song, Xuexiong; Huan, Yanjun; Gao, Shansong; Jiang, Zhongling

    2018-01-01

    Access to adequate anatomical specimens can be an important aspect in learning the anatomy of domestic animals. In this study, the authors utilized a structured light scanner and fused deposition modeling (FDM) printer to produce highly accurate animal skeletal models. First, various components of the bovine skeleton, including the femur, the…

  18. A model-updating procedure to stimulate piezoelectric transducers accurately.

    PubMed

    Piranda, B; Ballandras, S; Steichen, W; Hecart, B

    2001-09-01

    The use of numerical calculations based on finite element methods (FEM) has yielded significant improvements in the simulation and design of piezoelectric transducers piezoelectric transducer utilized in acoustic imaging. However, the ultimate precision of such models is directly controlled by the accuracy of material characterization. The present work is dedicated to the development of a model-updating technique adapted to the problem of piezoelectric transducer. The updating process is applied using the experimental admittance of a given structure for which a finite element analysis is performed. The mathematical developments are reported and then applied to update the entries of a FEM of a two-layer structure (a PbZrTi-PZT-ridge glued on a backing) for which measurements were available. The efficiency of the proposed approach is demonstrated, yielding the definition of a new set of constants well adapted to predict the structure response accurately. Improvement of the proposed approach, consisting of the updating of material coefficients not only on the admittance but also on the impedance data, is finally discussed.

  19. Accurate modeling of switched reluctance machine based on hybrid trained WNN

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Song, Shoujun, E-mail: sunnyway@nwpu.edu.cn; Ge, Lefei; Ma, Shaojie

    2014-04-15

    According to the strong nonlinear electromagnetic characteristics of switched reluctance machine (SRM), a novel accurate modeling method is proposed based on hybrid trained wavelet neural network (WNN) which combines improved genetic algorithm (GA) with gradient descent (GD) method to train the network. In the novel method, WNN is trained by GD method based on the initial weights obtained per improved GA optimization, and the global parallel searching capability of stochastic algorithm and local convergence speed of deterministic algorithm are combined to enhance the training accuracy, stability and speed. Based on the measured electromagnetic characteristics of a 3-phase 12/8-pole SRM, themore » nonlinear simulation model is built by hybrid trained WNN in Matlab. The phase current and mechanical characteristics from simulation under different working conditions meet well with those from experiments, which indicates the accuracy of the model for dynamic and static performance evaluation of SRM and verifies the effectiveness of the proposed modeling method.« less

  20. Accurate Induction Energies for Small Organic Molecules. 2. Development and Testing of Distributed Polarizability Models against SAPT(DFT) Energies.

    PubMed

    Misquitta, Alston J; Stone, Anthony J; Price, Sarah L

    2008-01-01

    In part 1 of this two-part investigation we set out the theoretical basis for constructing accurate models of the induction energy of clusters of moderately sized organic molecules. In this paper we use these techniques to develop a variety of accurate distributed polarizability models for a set of representative molecules that include formamide, N-methyl propanamide, benzene, and 3-azabicyclo[3.3.1]nonane-2,4-dione. We have also explored damping, penetration, and basis set effects. In particular, we have provided a way to treat the damping of the induction expansion. Different approximations to the induction energy are evaluated against accurate SAPT(DFT) energies, and we demonstrate the accuracy of our induction models on the formamide-water dimer.

  1. Evaluation of the Williams-type spring wheat model in North Dakota and Minnesota

    NASA Technical Reports Server (NTRS)

    Leduc, S. (Principal Investigator)

    1982-01-01

    The Williams type model, developed similarly to previous models of C.V.D. Williams, uses monthly temperature and precipitation data as well as soil and topological variables to predict the yield of the spring wheat crop. The models are statistically developed using the regression technique. Eight model characteristics are examined in the evaluation of the model. Evaluation is at the crop reporting district level, the state level and for the entire region. A ten year bootstrap test was the basis of the statistical evaluation. The accuracy and current indication of modeled yield reliability could show improvement. There is great variability in the bias measured over the districts, but there is a slight overall positive bias. The model estimates for the east central crop reporting district in Minnesota are not accurate. The estimate of yield for 1974 were inaccurate for all of the models.

  2. Boussinesq Modeling for Inlets, Harbors, and Structures (Bouss-2D)

    DTIC Science & Technology

    2015-10-30

    a wide variety of coastal and ocean engineering and naval architecture problems, including: transformation of waves over small to medium spatial...and outputs, and GIS data used in modeling. Recent applications include: Pillar Point Harbor, Oyster Point Marina, CA; Mouth of Columbia River

  3. Accurate, high-throughput typing of copy number variation using paralogue ratios from dispersed repeats

    PubMed Central

    Armour, John A. L.; Palla, Raquel; Zeeuwen, Patrick L. J. M.; den Heijer, Martin; Schalkwijk, Joost; Hollox, Edward J.

    2007-01-01

    Recent work has demonstrated an unexpected prevalence of copy number variation in the human genome, and has highlighted the part this variation may play in predisposition to common phenotypes. Some important genes vary in number over a high range (e.g. DEFB4, which commonly varies between two and seven copies), and have posed formidable technical challenges for accurate copy number typing, so that there are no simple, cheap, high-throughput approaches suitable for large-scale screening. We have developed a simple comparative PCR method based on dispersed repeat sequences, using a single pair of precisely designed primers to amplify products simultaneously from both test and reference loci, which are subsequently distinguished and quantified via internal sequence differences. We have validated the method for the measurement of copy number at DEFB4 by comparison of results from >800 DNA samples with copy number measurements by MAPH/REDVR, MLPA and array-CGH. The new Paralogue Ratio Test (PRT) method can require as little as 10 ng genomic DNA, appears to be comparable in accuracy to the other methods, and for the first time provides a rapid, simple and inexpensive method for copy number analysis, suitable for application to typing thousands of samples in large case-control association studies. PMID:17175532

  4. Development of Improved Algorithms and Multiscale Modeling Capability with SUNTANS

    DTIC Science & Technology

    2013-09-30

    solves the Navier-Stokes equations under the Boussinesq approximation (Fringer et al.,2006). The formulation is based on the method outlined by...stratified systems . Figure 4 shows a nonhydrostatic isopycnal simulation of oscillatory flow in a continuously stratified fluid over a Gaussian sill. This...Modeling the Earth System , Boulder (invited). Sankaranarayanan, S., and Fringer, O. B., 2013, "Dynamics of barotropic low-frequency fluctuations in

  5. An improvement of convergence of a dispersion-relation preserving method for the classical Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Jang, T. S.

    2018-03-01

    A dispersion-relation preserving (DRP) method, as a semi-analytic iterative procedure, has been proposed by Jang (2017) for integrating the classical Boussinesq equation. It has been shown to be a powerful numerical procedure for simulating a nonlinear dispersive wave system because it preserves the dispersion-relation, however, there still exists a potential flaw, e.g., a restriction on nonlinear wave amplitude and a small region of convergence (ROC) and so on. To remedy the flaw, a new DRP method is proposed in this paper, aimed at improving convergence performance. The improved method is proved to have convergence properties and dispersion-relation preserving nature for small waves; of course, unique existence of the solutions is also proved. In addition, by a numerical experiment, the method is confirmed to be good at observing nonlinear wave phenomena such as moving solitary waves and their binary collision with different wave amplitudes. Especially, it presents a ROC (much) wider than that of the previous method by Jang (2017). Moreover, it gives the numerical simulation of a high (or large-amplitude) nonlinear dispersive wave. In fact, it is demonstrated to simulate a large-amplitude solitary wave and the collision of two solitary waves with large-amplitudes that we have failed to simulate with the previous method. Conclusively, it is worth noting that better convergence results are achieved compared to Jang (2017); i.e., they represent a major improvement in practice over the previous method.

  6. Helicopter flight dynamics simulation with a time-accurate free-vortex wake model

    NASA Astrophysics Data System (ADS)

    Ribera, Maria

    This dissertation describes the implementation and validation of a coupled rotor-fuselage simulation model with a time-accurate free-vortex wake model capable of capturing the response to maneuvers of arbitrary amplitude. The resulting model has been used to analyze different flight conditions, including both steady and transient maneuvers. The flight dynamics model is based on a system of coupled nonlinear rotor-fuselage differential equations in first-order, state-space form. The rotor model includes flexible blades, with coupled flap-lag-torsion dynamics and swept tips; the rigid body dynamics are modeled with the non-linear Euler equations. The free wake models the rotor flow field by tracking the vortices released at the blade tips. Their behavior is described by the equations of vorticity transport, which is approximated using finite differences, and solved using a time-accurate numerical scheme. The flight dynamics model can be solved as a system of non-linear algebraic trim equations to determine the steady state solution, or integrated in time in response to pilot-applied controls. This study also implements new approaches to reduce the prohibitive computational costs associated with such complex models without losing accuracy. The mathematical model was validated for trim conditions in level flight, turns, climbs and descents. The results obtained correlate well with flight test data, both in level flight as well as turning and climbing and descending flight. The swept tip model was also found to improve the trim predictions, particularly at high speed. The behavior of the rigid body and the rotor blade dynamics were also studied and related to the aerodynamic load distributions obtained with the free wake induced velocities. The model was also validated in a lateral maneuver from hover. The results show improvements in the on-axis prediction, and indicate a possible relation between the off-axis prediction and the lack of rotor-body interaction

  7. An accurate and efficient laser-envelope solver for the modeling of laser-plasma accelerators

    DOE PAGES

    Benedetti, C.; Schroeder, C. B.; Geddes, C. G. R.; ...

    2017-10-17

    Detailed and reliable numerical modeling of laser-plasma accelerators (LPAs), where a short and intense laser pulse interacts with an underdense plasma over distances of up to a meter, is a formidably challenging task. This is due to the great disparity among the length scales involved in the modeling, ranging from the micron scale of the laser wavelength to the meter scale of the total laser-plasma interaction length. The use of the time-averaged ponderomotive force approximation, where the laser pulse is described by means of its envelope, enables efficient modeling of LPAs by removing the need to model the details ofmore » electron motion at the laser wavelength scale. Furthermore, it allows simulations in cylindrical geometry which captures relevant 3D physics at 2D computational cost. A key element of any code based on the time-averaged ponderomotive force approximation is the laser envelope solver. In this paper we present the accurate and efficient envelope solver used in the code INF & RNO (INtegrated Fluid & paRticle simulatioN cOde). The features of the INF & RNO laser solver enable an accurate description of the laser pulse evolution deep into depletion even at a reasonably low resolution, resulting in significant computational speed-ups.« less

  8. An accurate and efficient laser-envelope solver for the modeling of laser-plasma accelerators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Benedetti, C.; Schroeder, C. B.; Geddes, C. G. R.

    Detailed and reliable numerical modeling of laser-plasma accelerators (LPAs), where a short and intense laser pulse interacts with an underdense plasma over distances of up to a meter, is a formidably challenging task. This is due to the great disparity among the length scales involved in the modeling, ranging from the micron scale of the laser wavelength to the meter scale of the total laser-plasma interaction length. The use of the time-averaged ponderomotive force approximation, where the laser pulse is described by means of its envelope, enables efficient modeling of LPAs by removing the need to model the details ofmore » electron motion at the laser wavelength scale. Furthermore, it allows simulations in cylindrical geometry which captures relevant 3D physics at 2D computational cost. A key element of any code based on the time-averaged ponderomotive force approximation is the laser envelope solver. In this paper we present the accurate and efficient envelope solver used in the code INF & RNO (INtegrated Fluid & paRticle simulatioN cOde). The features of the INF & RNO laser solver enable an accurate description of the laser pulse evolution deep into depletion even at a reasonably low resolution, resulting in significant computational speed-ups.« less

  9. An accurate and efficient laser-envelope solver for the modeling of laser-plasma accelerators

    NASA Astrophysics Data System (ADS)

    Benedetti, C.; Schroeder, C. B.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

    2018-01-01

    Detailed and reliable numerical modeling of laser-plasma accelerators (LPAs), where a short and intense laser pulse interacts with an underdense plasma over distances of up to a meter, is a formidably challenging task. This is due to the great disparity among the length scales involved in the modeling, ranging from the micron scale of the laser wavelength to the meter scale of the total laser-plasma interaction length. The use of the time-averaged ponderomotive force approximation, where the laser pulse is described by means of its envelope, enables efficient modeling of LPAs by removing the need to model the details of electron motion at the laser wavelength scale. Furthermore, it allows simulations in cylindrical geometry which captures relevant 3D physics at 2D computational cost. A key element of any code based on the time-averaged ponderomotive force approximation is the laser envelope solver. In this paper we present the accurate and efficient envelope solver used in the code INF&RNO (INtegrated Fluid & paRticle simulatioN cOde). The features of the INF&RNO laser solver enable an accurate description of the laser pulse evolution deep into depletion even at a reasonably low resolution, resulting in significant computational speed-ups.

  10. An accurate behavioral model for single-photon avalanche diode statistical performance simulation

    NASA Astrophysics Data System (ADS)

    Xu, Yue; Zhao, Tingchen; Li, Ding

    2018-01-01

    An accurate behavioral model is presented to simulate important statistical performance of single-photon avalanche diodes (SPADs), such as dark count and after-pulsing noise. The derived simulation model takes into account all important generation mechanisms of the two kinds of noise. For the first time, thermal agitation, trap-assisted tunneling and band-to-band tunneling mechanisms are simultaneously incorporated in the simulation model to evaluate dark count behavior of SPADs fabricated in deep sub-micron CMOS technology. Meanwhile, a complete carrier trapping and de-trapping process is considered in afterpulsing model and a simple analytical expression is derived to estimate after-pulsing probability. In particular, the key model parameters of avalanche triggering probability and electric field dependence of excess bias voltage are extracted from Geiger-mode TCAD simulation and this behavioral simulation model doesn't include any empirical parameters. The developed SPAD model is implemented in Verilog-A behavioral hardware description language and successfully operated on commercial Cadence Spectre simulator, showing good universality and compatibility. The model simulation results are in a good accordance with the test data, validating high simulation accuracy.

  11. Lagrangian particle statistics of numerically simulated shear waves

    NASA Astrophysics Data System (ADS)

    Kirby, J.; Briganti, R.; Brocchini, M.; Chen, Q. J.

    2006-12-01

    The properties of numerical solutions of various circulation models (Boussinesq-type and wave-averaged NLSWE) have been investigated on the basis of the induced horizontal flow mixing, for the case of shear waves. The mixing properties of the flow have been investigated using particle statistics, following the approach of LaCasce (2001) and Piattella et al. (2006). Both an idealized barred beach bathymetry and a test case taken from SANDYDUCK '97 have been considered. Random seeding patterns of passive tracer particles are used. The flow exhibits features similar to those discussed in literature. Differences are also evident due both to the physics (intense longshore shear shoreward of the bar) and the procedure used to obtain the statistics (lateral conditions limit the time/space window for the longshore flow). Within the Boussinesq framework, different formulations of Boussinesq type equations have been used and the results compared (Wei et al. 1995, Chen et al. (2003), Chen et al. (2006)). Analysis based on the Eulerian velocity fields suggests a close similarity between Wei et al. (1995) and Chen et. al (2006), while examination of particle displacements and implied mixing suggests a closer behaviour between Chen et al. (2003) and Chen et al. (2006). Two distinct stages of mixing are evident in all simulations: i) the first stage ends at t

  12. Double Cluster Heads Model for Secure and Accurate Data Fusion in Wireless Sensor Networks

    PubMed Central

    Fu, Jun-Song; Liu, Yun

    2015-01-01

    Secure and accurate data fusion is an important issue in wireless sensor networks (WSNs) and has been extensively researched in the literature. In this paper, by combining clustering techniques, reputation and trust systems, and data fusion algorithms, we propose a novel cluster-based data fusion model called Double Cluster Heads Model (DCHM) for secure and accurate data fusion in WSNs. Different from traditional clustering models in WSNs, two cluster heads are selected after clustering for each cluster based on the reputation and trust system and they perform data fusion independently of each other. Then, the results are sent to the base station where the dissimilarity coefficient is computed. If the dissimilarity coefficient of the two data fusion results exceeds the threshold preset by the users, the cluster heads will be added to blacklist, and the cluster heads must be reelected by the sensor nodes in a cluster. Meanwhile, feedback is sent from the base station to the reputation and trust system, which can help us to identify and delete the compromised sensor nodes in time. Through a series of extensive simulations, we found that the DCHM performed very well in data fusion security and accuracy. PMID:25608211

  13. Radiation Transport in Type IA Supernovae

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Eastman, R

    1999-11-16

    It has been said more than once that the critical link between explosion models and observations is the ability to accurately simulate cooling and radiation transport in the expanding ejecta of Type Ia supernovae. It is perhaps frustrating to some of the theorists who study explosion mechanisms, and to some of the observers too, that more definitive conclusions have not been reached about the agreement, or lack thereof, between various Type Ia supernova models and the data. Although claims of superlative accuracy in transport simulations are sometimes made, I will argue here that there are outstanding issues of critical importancemore » and in need of addressing before radiation transport calculations are accurate enough to discriminate between subtly different explosion models.« less

  14. How Accurate Is A Hydraulic Model? | Science Inventory | US ...

    EPA Pesticide Factsheets

    Symposium paper Network hydraulic models are widely used, but their overall accuracy is often unknown. Models are developed to give utilities better insight into system hydraulic behavior, and increasingly the ability to predict the fate and transport of chemicals. Without an accessible and consistent means of validating a given model against the system it is meant to represent, the value of those supposed benefits should be questioned. Supervisory Control And Data Acquisition (SCADA) databases, though ubiquitous, are underused data sources for this type of task. Integrating a network model with a measurement database would offer professionals the ability to assess the model’s assumptions in an automated fashion by leveraging enormous amounts of data.

  15. A hamster model for Marburg virus infection accurately recapitulates Marburg hemorrhagic fever

    PubMed Central

    Marzi, Andrea; Banadyga, Logan; Haddock, Elaine; Thomas, Tina; Shen, Kui; Horne, Eva J.; Scott, Dana P.; Feldmann, Heinz; Ebihara, Hideki

    2016-01-01

    Marburg virus (MARV), a close relative of Ebola virus, is the causative agent of a severe human disease known as Marburg hemorrhagic fever (MHF). No licensed vaccine or therapeutic exists to treat MHF, and MARV is therefore classified as a Tier 1 select agent and a category A bioterrorism agent. In order to develop countermeasures against this severe disease, animal models that accurately recapitulate human disease are required. Here we describe the development of a novel, uniformly lethal Syrian golden hamster model of MHF using a hamster-adapted MARV variant Angola. Remarkably, this model displayed almost all of the clinical features of MHF seen in humans and non-human primates, including coagulation abnormalities, hemorrhagic manifestations, petechial rash, and a severely dysregulated immune response. This MHF hamster model represents a powerful tool for further dissecting MARV pathogenesis and accelerating the development of effective medical countermeasures against human MHF. PMID:27976688

  16. A hamster model for Marburg virus infection accurately recapitulates Marburg hemorrhagic fever.

    PubMed

    Marzi, Andrea; Banadyga, Logan; Haddock, Elaine; Thomas, Tina; Shen, Kui; Horne, Eva J; Scott, Dana P; Feldmann, Heinz; Ebihara, Hideki

    2016-12-15

    Marburg virus (MARV), a close relative of Ebola virus, is the causative agent of a severe human disease known as Marburg hemorrhagic fever (MHF). No licensed vaccine or therapeutic exists to treat MHF, and MARV is therefore classified as a Tier 1 select agent and a category A bioterrorism agent. In order to develop countermeasures against this severe disease, animal models that accurately recapitulate human disease are required. Here we describe the development of a novel, uniformly lethal Syrian golden hamster model of MHF using a hamster-adapted MARV variant Angola. Remarkably, this model displayed almost all of the clinical features of MHF seen in humans and non-human primates, including coagulation abnormalities, hemorrhagic manifestations, petechial rash, and a severely dysregulated immune response. This MHF hamster model represents a powerful tool for further dissecting MARV pathogenesis and accelerating the development of effective medical countermeasures against human MHF.

  17. Can phenological models predict tree phenology accurately in the future? The unrevealed hurdle of endodormancy break.

    PubMed

    Chuine, Isabelle; Bonhomme, Marc; Legave, Jean-Michel; García de Cortázar-Atauri, Iñaki; Charrier, Guillaume; Lacointe, André; Améglio, Thierry

    2016-10-01

    The onset of the growing season of trees has been earlier by 2.3 days per decade during the last 40 years in temperate Europe because of global warming. The effect of temperature on plant phenology is, however, not linear because temperature has a dual effect on bud development. On one hand, low temperatures are necessary to break bud endodormancy, and, on the other hand, higher temperatures are necessary to promote bud cell growth afterward. Different process-based models have been developed in the last decades to predict the date of budbreak of woody species. They predict that global warming should delay or compromise endodormancy break at the species equatorward range limits leading to a delay or even impossibility to flower or set new leaves. These models are classically parameterized with flowering or budbreak dates only, with no information on the endodormancy break date because this information is very scarce. Here, we evaluated the efficiency of a set of phenological models to accurately predict the endodormancy break dates of three fruit trees. Our results show that models calibrated solely with budbreak dates usually do not accurately predict the endodormancy break date. Providing endodormancy break date for the model parameterization results in much more accurate prediction of this latter, with, however, a higher error than that on budbreak dates. Most importantly, we show that models not calibrated with endodormancy break dates can generate large discrepancies in forecasted budbreak dates when using climate scenarios as compared to models calibrated with endodormancy break dates. This discrepancy increases with mean annual temperature and is therefore the strongest after 2050 in the southernmost regions. Our results claim for the urgent need of massive measurements of endodormancy break dates in forest and fruit trees to yield more robust projections of phenological changes in a near future. © 2016 John Wiley & Sons Ltd.

  18. Multiscale Methods for Accurate, Efficient, and Scale-Aware Models of the Earth System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Goldhaber, Steve; Holland, Marika

    The major goal of this project was to contribute improvements to the infrastructure of an Earth System Model in order to support research in the Multiscale Methods for Accurate, Efficient, and Scale-Aware models of the Earth System project. In support of this, the NCAR team accomplished two main tasks: improving input/output performance of the model and improving atmospheric model simulation quality. Improvement of the performance and scalability of data input and diagnostic output within the model required a new infrastructure which can efficiently handle the unstructured grids common in multiscale simulations. This allows for a more computationally efficient model, enablingmore » more years of Earth System simulation. The quality of the model simulations was improved by reducing grid-point noise in the spectral element version of the Community Atmosphere Model (CAM-SE). This was achieved by running the physics of the model using grid-cell data on a finite-volume grid.« less

  19. Combining Structural Modeling with Ensemble Machine Learning to Accurately Predict Protein Fold Stability and Binding Affinity Effects upon Mutation

    PubMed Central

    Garcia Lopez, Sebastian; Kim, Philip M.

    2014-01-01

    Advances in sequencing have led to a rapid accumulation of mutations, some of which are associated with diseases. However, to draw mechanistic conclusions, a biochemical understanding of these mutations is necessary. For coding mutations, accurate prediction of significant changes in either the stability of proteins or their affinity to their binding partners is required. Traditional methods have used semi-empirical force fields, while newer methods employ machine learning of sequence and structural features. Here, we show how combining both of these approaches leads to a marked boost in accuracy. We introduce ELASPIC, a novel ensemble machine learning approach that is able to predict stability effects upon mutation in both, domain cores and domain-domain interfaces. We combine semi-empirical energy terms, sequence conservation, and a wide variety of molecular details with a Stochastic Gradient Boosting of Decision Trees (SGB-DT) algorithm. The accuracy of our predictions surpasses existing methods by a considerable margin, achieving correlation coefficients of 0.77 for stability, and 0.75 for affinity predictions. Notably, we integrated homology modeling to enable proteome-wide prediction and show that accurate prediction on modeled structures is possible. Lastly, ELASPIC showed significant differences between various types of disease-associated mutations, as well as between disease and common neutral mutations. Unlike pure sequence-based prediction methods that try to predict phenotypic effects of mutations, our predictions unravel the molecular details governing the protein instability, and help us better understand the molecular causes of diseases. PMID:25243403

  20. Do Skilled Elementary Teachers Hold Scientific Conceptions and Can They Accurately Predict the Type and Source of Students' Preconceptions of Electric Circuits?

    ERIC Educational Resources Information Center

    Lin, Jing-Wen

    2016-01-01

    Holding scientific conceptions and having the ability to accurately predict students' preconceptions are a prerequisite for science teachers to design appropriate constructivist-oriented learning experiences. This study explored the types and sources of students' preconceptions of electric circuits. First, 438 grade 3 (9 years old) students were…

  1. Sensitivities of the hydrologic cycle to model physics, grid resolution, and ocean type in the aquaplanet Community Atmosphere Model

    NASA Astrophysics Data System (ADS)

    Benedict, James J.; Medeiros, Brian; Clement, Amy C.; Pendergrass, Angeline G.

    2017-06-01

    Precipitation distributions and extremes play a fundamental role in shaping Earth's climate and yet are poorly represented in many global climate models. Here, a suite of idealized Community Atmosphere Model (CAM) aquaplanet simulations is examined to assess the aquaplanet's ability to reproduce hydroclimate statistics of real-Earth configurations and to investigate sensitivities of precipitation distributions and extremes to model physics, horizontal grid resolution, and ocean type. Little difference in precipitation statistics is found between aquaplanets using time-constant sea-surface temperatures and those implementing a slab ocean model with a 50 m mixed-layer depth. In contrast, CAM version 5.3 (CAM5.3) produces more time mean, zonally averaged precipitation than CAM version 4 (CAM4), while CAM4 generates significantly larger precipitation variance and frequencies of extremely intense precipitation events. The largest model configuration-based precipitation sensitivities relate to choice of horizontal grid resolution in the selected range 1-2°. Refining grid resolution has significant physics-dependent effects on tropical precipitation: for CAM4, time mean zonal mean precipitation increases along the Equator and the intertropical convergence zone (ITCZ) narrows, while for CAM5.3 precipitation decreases along the Equator and the twin branches of the ITCZ shift poleward. Increased grid resolution also reduces light precipitation frequencies and enhances extreme precipitation for both CAM4 and CAM5.3 resulting in better alignment with observational estimates. A discussion of the potential implications these hydrologic cycle sensitivities have on the interpretation of precipitation statistics in future climate projections is also presented.type="synopsis">type</span>="main">Plain Language SummaryPrecipitation plays a fundamental role in shaping Earth's climate. Global climate <span class="hlt">models</span> predict the average precipitation reasonably well but often struggle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28089708','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28089708"><span>Hair corticosterone measurement in mouse <span class="hlt">models</span> of <span class="hlt">type</span> 1 and <span class="hlt">type</span> 2 diabetes mellitus.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Erickson, Rebecca L; Browne, Caroline A; Lucki, Irwin</p> <p>2017-09-01</p> <p>In diabetes, glucocorticoid secretion increases secondary to hyperglycemia and is associated with an extensive list of disease complications. Levels of cortisol in humans, or corticosterone in rodents, are usually measured as transitory biomarkers of stress in blood or saliva. Glucocorticoid concentrations accumulate in human or animal hair over weeks and could more <span class="hlt">accurately</span> measure the cumulative stress burden of diseases like chronic diabetes. In this study, corticosterone levels were measured in hair in verified rodent <span class="hlt">models</span> of diabetes mellitus. To induce <span class="hlt">type</span> 1 diabetes, C57BL/6J mice were injected with streptozotocin and blood and hair samples were collected 28days following induction. Leptin receptor deficient (db/db) mice were used as a spontaneous <span class="hlt">model</span> of <span class="hlt">type</span> 2 diabetes and blood and hair samples were collected at 8weeks of age, after the development of hyperglycemia and obesity. Corticosterone levels from serum, new growth hair and total growth hair were analyzed using an enzyme immunoassay. Corticosterone levels in new growth hair and serum were significantly elevated in both <span class="hlt">models</span> of diabetes compared to controls. In contrast, corticosterone levels in old hair growth did not differ significantly between diabetic and non-diabetic animals. Thus, hair removal and sampling of new hair growth was a more sensitive procedure for detecting changes in hair corticosterone levels induced by periods of hyperglycemia lasting for 4weeks in mice. These results validate the use of hair to measure long-term changes in corticosterone induced by diabetes in rodent <span class="hlt">models</span>. Further studies are now needed to validate the utility of hair cortisol as a tool for measuring the stress burden of individuals with diabetes and for following the effects of long-term medical treatments. Copyright © 2017 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26192831','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26192831"><span>Fast and <span class="hlt">accurate</span> focusing analysis of large photon sieve using pinhole ring diffraction <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Tao; Zhang, Xin; Wang, Lingjie; Wu, Yanxiong; Zhang, Jizhen; Qu, Hemeng</p> <p>2015-06-10</p> <p>In this paper, we developed a pinhole ring diffraction <span class="hlt">model</span> for the focusing analysis of a large photon sieve. Instead of analyzing individual pinholes, we discuss the focusing of all of the pinholes in a single ring. An explicit equation for the diffracted field of individual pinhole ring has been proposed. We investigated the validity range of this generalized <span class="hlt">model</span> and analytically describe the sufficient conditions for the validity of this pinhole ring diffraction <span class="hlt">model</span>. A practical example and investigation reveals the high accuracy of the pinhole ring diffraction <span class="hlt">model</span>. This simulation method could be used for fast and <span class="hlt">accurate</span> focusing analysis of a large photon sieve.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27411150','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27411150"><span>Branch and bound algorithm for <span class="hlt">accurate</span> estimation of analytical isotropic bidirectional reflectance distribution function <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yu, Chanki; Lee, Sang Wook</p> <p>2016-05-20</p> <p>We present a reliable and <span class="hlt">accurate</span> global optimization framework for estimating parameters of isotropic analytical bidirectional reflectance distribution function (BRDF) <span class="hlt">models</span>. This approach is based on a branch and bound strategy with linear programming and interval analysis. Conventional local optimization is often very inefficient for BRDF estimation since its fitting quality is highly dependent on initial guesses due to the nonlinearity of analytical BRDF <span class="hlt">models</span>. The algorithm presented in this paper employs L<sub>1</sub>-norm error minimization to estimate BRDF parameters in a globally optimal way and interval arithmetic to derive our feasibility problem and lower bounding function. Our method is developed for the Cook-Torrance <span class="hlt">model</span> but with several normal distribution functions such as the Beckmann, Berry, and GGX functions. Experiments have been carried out to validate the presented method using 100 isotropic materials from the MERL BRDF database, and our experimental results demonstrate that the L<sub>1</sub>-norm minimization provides a more <span class="hlt">accurate</span> and reliable solution than the L<sub>2</sub>-norm minimization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=cad&pg=6&id=EJ916642','ERIC'); return false;" href="https://eric.ed.gov/?q=cad&pg=6&id=EJ916642"><span>Pre-<span class="hlt">Modeling</span> Ensures <span class="hlt">Accurate</span> Solid <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Gow, George</p> <p>2010-01-01</p> <p>Successful solid <span class="hlt">modeling</span> requires a well-organized design tree. The design tree is a list of all the object's features and the sequential order in which they are <span class="hlt">modeled</span>. The solid-<span class="hlt">modeling</span> process is faster and less prone to <span class="hlt">modeling</span> errors when the design tree is a simple and geometrically logical definition of the <span class="hlt">modeled</span> object. Few high…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16606097','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16606097"><span>Defect chaos and bursts: hexagonal rotating convection and the complex Ginzburg-Landau equation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Madruga, Santiago; Riecke, Hermann; Pesch, Werner</p> <p>2006-02-24</p> <p>We employ numerical computations of the full Navier-Stokes equations to investigate non-<span class="hlt">Boussinesq</span> convection in a rotating system using water as the working fluid. We identify two regimes. For weak non-<span class="hlt">Boussinesq</span> effects the Hopf bifurcation from steady to oscillating (whirling) hexagons is supercritical and typical states exhibit defect chaos that is systematically described by the cubic complex Ginzburg-Landau equation. For stronger non-<span class="hlt">Boussinesq</span> effects the Hopf bifurcation becomes subcritical and the oscillations exhibit localized chaotic bursting, which is <span class="hlt">modeled</span> by a quintic complex Ginzburg-Landau equation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MPLB...3140045Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MPLB...3140045Y"><span>An automatic and <span class="hlt">accurate</span> method of full heart segmentation from CT image based on linear gradient <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Zili</p> <p>2017-07-01</p> <p>Heart segmentation is an important auxiliary method in the diagnosis of many heart diseases, such as coronary heart disease and atrial fibrillation, and in the planning of tumor radiotherapy. Most of the existing methods for full heart segmentation treat the heart as a whole part and cannot <span class="hlt">accurately</span> extract the bottom of the heart. In this paper, we propose a new method based on linear gradient <span class="hlt">model</span> to segment the whole heart from the CT images automatically and <span class="hlt">accurately</span>. Twelve cases were tested in order to test this method and <span class="hlt">accurate</span> segmentation results were achieved and identified by clinical experts. The results can provide reliable clinical support.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..276a2038A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..276a2038A"><span>An <span class="hlt">accurate</span> fatigue damage <span class="hlt">model</span> for welded joints subjected to variable amplitude loading</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aeran, A.; Siriwardane, S. C.; Mikkelsen, O.; Langen, I.</p> <p>2017-12-01</p> <p>Researchers in the past have proposed several fatigue damage <span class="hlt">models</span> to overcome the shortcomings of the commonly used Miner’s rule. However, requirements of material parameters or S-N curve modifications restricts their practical applications. Also, application of most of these <span class="hlt">models</span> under variable amplitude loading conditions have not been found. To overcome these restrictions, a new fatigue damage <span class="hlt">model</span> is proposed in this paper. The proposed <span class="hlt">model</span> can be applied by practicing engineers using only the S-N curve given in the standard codes of practice. The <span class="hlt">model</span> is verified with experimentally derived damage evolution curves for C 45 and 16 Mn and gives better agreement compared to previous <span class="hlt">models</span>. The <span class="hlt">model</span> predicted fatigue lives are also in better correlation with experimental results compared to previous <span class="hlt">models</span> as shown in earlier published work by the authors. The proposed <span class="hlt">model</span> is applied to welded joints subjected to variable amplitude loadings in this paper. The <span class="hlt">model</span> given around 8% shorter fatigue lives compared to Eurocode given Miner’s rule. This shows the importance of applying <span class="hlt">accurate</span> fatigue damage <span class="hlt">models</span> for welded joints.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3310093','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3310093"><span><span class="hlt">Modeling</span> Insights into Haemophilus influenzae <span class="hlt">Type</span> b Disease, Transmission, and Vaccine Programs</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rose, Charles E.; Cohn, Amanda; Coronado, Fatima; Clark, Thomas A.; Wenger, Jay D.; Bulkow, Lisa; Bruce, Michael G.; Messonnier, Nancy E.; Hennessy, Thomas W.</p> <p>2012-01-01</p> <p>In response to the 2007–2009 Haemophilus influenzae <span class="hlt">type</span> b (Hib) vaccine shortage in the United States, we developed a flexible <span class="hlt">model</span> of Hib transmission and disease for optimizing Hib vaccine programs in diverse populations and situations. The <span class="hlt">model</span> classifies population members by age, colonization/disease status, and antibody levels, with movement across categories defined by differential equations. We implemented the <span class="hlt">model</span> for the United States as a whole, England and Wales, and the Alaska Native population. This <span class="hlt">model</span> <span class="hlt">accurately</span> simulated Hib incidence in all 3 populations, including the increased incidence in England/Wales beginning in 1999 and the change in Hib incidence in Alaska Natives after switching Hib vaccines in 1996. The <span class="hlt">model</span> suggests that a vaccine shortage requiring deferral of the booster dose could last 3 years in the United States before loss of herd immunity would result in increasing rates of invasive Hib disease in children <5 years of age. PMID:22257582</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70159298','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70159298"><span>Mapping forest functional <span class="hlt">type</span> in a forest-shrubland ecotone using SPOT imagery and predictive habitat distribution <span class="hlt">modelling</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Assal, Timothy J.; Anderson, Patrick J.; Sibold, Jason</p> <p>2015-01-01</p> <p>The availability of land cover data at local scales is an important component in forest management and monitoring efforts. Regional land cover data seldom provide detailed information needed to support local management needs. Here we present a transferable framework to <span class="hlt">model</span> forest cover by major plant functional <span class="hlt">type</span> using aerial photos, multi-date Système Pour l’Observation de la Terre (SPOT) imagery, and topographic variables. We developed probability of occurrence <span class="hlt">models</span> for deciduous broad-leaved forest and needle-leaved evergreen forest using logistic regression in the southern portion of the Wyoming Basin Ecoregion. The <span class="hlt">model</span> outputs were combined into a synthesis map depicting deciduous and coniferous forest cover <span class="hlt">type</span>. We evaluated the <span class="hlt">models</span> and synthesis map using a field-validated, independent data source. Results showed strong relationships between forest cover and <span class="hlt">model</span> variables, and the synthesis map was <span class="hlt">accurate</span> with an overall correct classification rate of 0.87 and Cohen’s kappa value of 0.81. The results suggest our method adequately captures the functional <span class="hlt">type</span>, size, and distribution pattern of forest cover in a spatially heterogeneous landscape.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdAtS..35..671F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdAtS..35..671F"><span>Simulating Eastern- and Central-Pacific <span class="hlt">Type</span> ENSO Using a Simple Coupled <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Xianghui; Zheng, Fei</p> <p>2018-06-01</p> <p>Severe biases exist in state-of-the-art general circulation <span class="hlt">models</span> (GCMs) in capturing realistic central-Pacific (CP) El Niño structures. At the same time, many observational analyses have emphasized that thermocline (TH) feedback and zonal advective (ZA) feedback play dominant roles in the development of eastern-Pacific (EP) and CP El Niño-Southern Oscillation (ENSO), respectively. In this work, a simple linear air-sea coupled <span class="hlt">model</span>, which can <span class="hlt">accurately</span> depict the strength distribution of the TH and ZA feedbacks in the equatorial Pacific, is used to investigate these two <span class="hlt">types</span> of El Niño. The results indicate that the <span class="hlt">model</span> can reproduce the main characteristics of CP ENSO if the TH feedback is switched off and the ZA feedback is retained as the only positive feedback, confirming the dominant role played by ZA feedback in the development of CP ENSO. Further experiments indicate that, through a simple nonlinear control approach, many ENSO characteristics, including the existence of both CP and EP El Niño and the asymmetries between El Niño and La Niña, can be successfully captured using the simple linear air-sea coupled <span class="hlt">model</span>. These analyses indicate that an <span class="hlt">accurate</span> depiction of the climatological sea surface temperature distribution and the related ZA feedback, which are the subject of severe biases in GCMs, is very important in simulating a realistic CP El Niño.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4851021','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4851021"><span>A Two-Phase Space Resection <span class="hlt">Model</span> for <span class="hlt">Accurate</span> Topographic Reconstruction from Lunar Imagery with PushbroomScanners</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xu, Xuemiao; Zhang, Huaidong; Han, Guoqiang; Kwan, Kin Chung; Pang, Wai-Man; Fang, Jiaming; Zhao, Gansen</p> <p>2016-01-01</p> <p>Exterior orientation parameters’ (EOP) estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing <span class="hlt">models</span> of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs) for space resection are error-prone. Thus, existing <span class="hlt">models</span> fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the <span class="hlt">modeling</span> of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical <span class="hlt">model</span>. Then, with the <span class="hlt">accurate</span> angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our <span class="hlt">model</span> can obtain more <span class="hlt">accurate</span> EOPs and topographic maps not only for the simulated data, but also for the real data from Chang’E-1, compared to the existing space resection <span class="hlt">model</span>. PMID:27077855</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27077855','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27077855"><span>A Two-Phase Space Resection <span class="hlt">Model</span> for <span class="hlt">Accurate</span> Topographic Reconstruction from Lunar Imagery with PushbroomScanners.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Xuemiao; Zhang, Huaidong; Han, Guoqiang; Kwan, Kin Chung; Pang, Wai-Man; Fang, Jiaming; Zhao, Gansen</p> <p>2016-04-11</p> <p>Exterior orientation parameters' (EOP) estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing <span class="hlt">models</span> of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs) for space resection are error-prone. Thus, existing <span class="hlt">models</span> fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the <span class="hlt">modeling</span> of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical <span class="hlt">model</span>. Then, with the <span class="hlt">accurate</span> angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our <span class="hlt">model</span> can obtain more <span class="hlt">accurate</span> EOPs and topographic maps not only for the simulated data, but also for the real data from Chang'E-1, compared to the existing space resection <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA620701','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA620701"><span>Double-Diffusive Convection in Rotational Shear</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2015-03-01</p> <p>salt finger development is 0 and 0Z ZT S> > . The <span class="hlt">model</span> uses the <span class="hlt">Boussinesq</span> equations of motion with the linear equations of state, are expressed in...reference density from the <span class="hlt">Boussinesq</span> approximation. ( )top bottom Z T T T H − = (2.2) The resultant non-dimensionalized equations for the <span class="hlt">model</span> are...S T k k t = to determine how the system evolved during the simulation. B. VERSIONS OF THE BASIC <span class="hlt">MODEL</span> This research was based on four separate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P23A2112K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P23A2112K"><span>Fast and <span class="hlt">Accurate</span> Radiative Transfer Calculations Using Principal Component Analysis for (Exo-)Planetary Retrieval <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kopparla, P.; Natraj, V.; Shia, R. L.; Spurr, R. J. D.; Crisp, D.; Yung, Y. L.</p> <p>2015-12-01</p> <p>Radiative transfer (RT) computations form the engine of atmospheric retrieval codes. However, full treatment of RT processes is computationally expensive, prompting usage of two-stream approximations in current exoplanetary atmospheric retrieval codes [Line et al., 2013]. Natraj et al. [2005, 2010] and Spurr and Natraj [2013] demonstrated the ability of a technique using principal component analysis (PCA) to speed up RT computations. In the PCA method for RT performance enhancement, empirical orthogonal functions are developed for binned sets of inherent optical properties that possess some redundancy; costly multiple-scattering RT calculations are only done for those few optical states corresponding to the most important principal components, and correction factors are applied to approximate radiation fields. Kopparla et al. [2015, in preparation] extended the PCA method to a broadband spectral region from the ultraviolet to the shortwave infrared (0.3-3 micron), accounting for major gas absorptions in this region. Here, we apply the PCA method to a some typical (exo-)planetary retrieval problems. Comparisons between the new <span class="hlt">model</span>, called Universal Principal Component Analysis Radiative Transfer (UPCART) <span class="hlt">model</span>, two-stream <span class="hlt">models</span> and line-by-line RT <span class="hlt">models</span> are performed, for spectral radiances, spectral fluxes and broadband fluxes. Each of these are calculated at the top of the atmosphere for several scenarios with varying aerosol <span class="hlt">types</span>, extinction and scattering optical depth profiles, and stellar and viewing geometries. We demonstrate that very <span class="hlt">accurate</span> radiance and flux estimates can be obtained, with better than 1% accuracy in all spectral regions and better than 0.1% in most cases, as compared to a numerically exact line-by-line RT <span class="hlt">model</span>. The accuracy is enhanced when the results are convolved to typical instrument resolutions. The operational speed and accuracy of UPCART can be further improved by optimizing binning schemes and parallelizing the codes, work</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23467166','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23467166"><span>An eclipsing-binary distance to the Large Magellanic Cloud <span class="hlt">accurate</span> to two per cent.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pietrzyński, G; Graczyk, D; Gieren, W; Thompson, I B; Pilecki, B; Udalski, A; Soszyński, I; Kozłowski, S; Konorski, P; Suchomska, K; Bono, G; Moroni, P G Prada; Villanova, S; Nardetto, N; Bresolin, F; Kudritzki, R P; Storm, J; Gallenne, A; Smolec, R; Minniti, D; Kubiak, M; Szymański, M K; Poleski, R; Wyrzykowski, L; Ulaczyk, K; Pietrukowicz, P; Górski, M; Karczmarek, P</p> <p>2013-03-07</p> <p>In the era of precision cosmology, it is essential to determine the Hubble constant to an accuracy of three per cent or better. At present, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC), which, being our second-closest galaxy, serves as the best anchor point for the cosmic distance scale. Observations of eclipsing binaries offer a unique opportunity to measure stellar parameters and distances precisely and <span class="hlt">accurately</span>. The eclipsing-binary method was previously applied to the LMC, but the accuracy of the distance results was lessened by the need to <span class="hlt">model</span> the bright, early-<span class="hlt">type</span> systems used in those studies. Here we report determinations of the distances to eight long-period, late-<span class="hlt">type</span> eclipsing systems in the LMC, composed of cool, giant stars. For these systems, we can <span class="hlt">accurately</span> measure both the linear and the angular sizes of their components and avoid the most important problems related to the hot, early-<span class="hlt">type</span> systems. The LMC distance that we derive from these systems (49.97 ± 0.19 (statistical) ± 1.11 (systematic) kiloparsecs) is <span class="hlt">accurate</span> to 2.2 per cent and provides a firm base for a 3-per-cent determination of the Hubble constant, with prospects for improvement to 2 per cent in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27943527','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27943527"><span>Three-dimensional endoanal ultrasound is <span class="hlt">accurate</span> and reproducible in determining <span class="hlt">type</span> and height of anal fistulas.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kołodziejczak, M; Santoro, G A; Obcowska, A; Lorenc, Z; Mańczak, M; Sudoł-Szopińska, I</p> <p>2017-04-01</p> <p>Surgical treatment of high anal fistulas is associated with the potential risk of faecal incontinence and recurrence. The primary aim of this study was to determine the accuracy of three-dimensional endoanal ultrasound (3D-EAUS) in the assessment of height and <span class="hlt">type</span> of anal fistulas, compared to the intra-operative findings (gold standard). The secondary aim was to evaluate the inter-observer reproducibility of 3D-EAUS. The study design was a prospective analysis of retrospective data. 299 patients (202 men), mean age 45.3 years, who underwent surgery for anal fistulas, were included. All patients were preoperatively assessed by 3D-EAUS. Two readers independently reviewed the volumes to determine the <span class="hlt">type</span> and height of fistulas. Sensitivity, specificity, positive and negative predictive values, proportion of agreements and Cohen's kappa coefficient (κ) were calculated for both examiners. Ultrasound findings were compared with intra-operative data (reference standard), evaluated blindly by the surgeons. At surgery, 201 (67%) were transsphincteric, 49 (16%) suprasphincteric, 47 (16%) intersphincteric and two (1%) extrasphincteric fistulas. Intra-operatively, 177 (59%) were low and 122 (41%) high fistulas. The overall accuracy of 3D-EAUS was 91% for fistula <span class="hlt">type</span> (271/299 fistulas: 97% transsphincteric, 100% intersphincteric, 57% suprasphincteric, 0% extrasphincteric) and 92% for fistula height (275/299 fistulas: 80% high and 100% low). Both readers reported very good agreement with surgery in the assessment of fistula <span class="hlt">type</span> (proportion of agreement 0.88, κ = 0.89) and height (proportion of agreement 0.90, κ = 0.91). 3D-EAUS is an <span class="hlt">accurate</span> and reproducible modality for the assessment of <span class="hlt">type</span> and height of anal fistulas. Colorectal Disease © 2016 The Association of Coloproctology of Great Britain and Ireland.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29752691','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29752691"><span>Analytical <span class="hlt">modelling</span> of temperature effects on an AMPA-<span class="hlt">type</span> synapse.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kufel, Dominik S; Wojcik, Grzegorz M</p> <p>2018-05-11</p> <p>It was previously reported, that temperature may significantly influence neural dynamics on the different levels of brain function. Thus, in computational neuroscience, it would be useful to make <span class="hlt">models</span> scalable for a wide range of various brain temperatures. However, lack of experimental data and an absence of temperature-dependent analytical <span class="hlt">models</span> of synaptic conductance does not allow to include temperature effects at the multi-neuron <span class="hlt">modeling</span> level. In this paper, we propose a first step to deal with this problem: A new analytical <span class="hlt">model</span> of AMPA-<span class="hlt">type</span> synaptic conductance, which is able to incorporate temperature effects in low-frequency stimulations. It was constructed based on Markov <span class="hlt">model</span> description of AMPA receptor kinetics using the set of coupled ODEs. The closed-form solution for the set of differential equations was found using uncoupling assumption (introduced in the paper) with few simplifications motivated both from experimental data and from Monte Carlo simulation of synaptic transmission. The <span class="hlt">model</span> may be used for computationally efficient and biologically <span class="hlt">accurate</span> implementation of temperature effects on AMPA receptor conductance in large-scale neural network simulations. As a result, it may open a wide range of new possibilities for researching the influence of temperature on certain aspects of brain functioning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19690000242','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19690000242"><span>Remote balance weighs <span class="hlt">accurately</span> amid high radiation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Eggenberger, D. N.; Shuck, A. B.</p> <p>1969-01-01</p> <p>Commercial beam-<span class="hlt">type</span> balance, modified and outfitted with electronic controls and digital readout, can be remotely controlled for use in high radiation environments. This allows <span class="hlt">accurate</span> weighing of breeder-reactor fuel pieces when they are radioactively hot.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1434893-communication-accurate-higher-order-van-der-waals-coefficients-between-molecules-from-model-dynamic-multipole-polarizability','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1434893-communication-accurate-higher-order-van-der-waals-coefficients-between-molecules-from-model-dynamic-multipole-polarizability"><span>Communication: <span class="hlt">Accurate</span> higher-order van der Waals coefficients between molecules from a <span class="hlt">model</span> dynamic multipole polarizability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Tao, Jianmin; Rappe, Andrew M.</p> <p>2016-01-20</p> <p>Due to the absence of the long-range van der Waals (vdW) interaction, conventional density functional theory (DFT) often fails in the description of molecular complexes and solids. In recent years, considerable progress has been made in the development of the vdW correction. However, the vdW correction based on the leading-order coefficient C 6 alone can only achieve limited accuracy, while <span class="hlt">accurate</span> <span class="hlt">modeling</span> of higher-order coefficients remains a formidable task, due to the strong non-additivity effect. Here, we apply a <span class="hlt">model</span> dynamic multipole polarizability within a modified single-frequency approximation to calculate C 8 and C 10 between small molecules. We findmore » that the higher-order vdW coefficients from this <span class="hlt">model</span> can achieve remarkable accuracy, with mean absolute relative deviations of 5% for C 8 and 7% for C 10. As a result, inclusion of <span class="hlt">accurate</span> higher-order contributions in the vdW correction will effectively enhance the predictive power of DFT in condensed matter physics and quantum chemistry.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036889','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036889"><span>Hydrodynamic <span class="hlt">modeling</span> of tsunamis from the Currituck landslide</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Geist, E.L.; Lynett, P.J.; Chaytor, J.D.</p> <p>2009-01-01</p> <p>Tsunami generation from the Currituck landslide offshore North Carolina and propagation of waves toward the U.S. coastline are <span class="hlt">modeled</span> based on recent geotechnical analysis of slide movement. A long and intermediate wave <span class="hlt">modeling</span> package (COULWAVE) based on the non-linear <span class="hlt">Boussinesq</span> equations are used to simulate the tsunami. This <span class="hlt">model</span> includes procedures to incorporate bottom friction, wave breaking, and overland flow during runup. Potential tsunamis generated from the Currituck landslide are analyzed using four approaches: (1) tsunami wave history is calculated from several different scenarios indicated by geotechnical stability and mobility analyses; (2) a sensitivity analysis is conducted to determine the effects of both landslide failure duration during generation and bottom friction along the continental shelf during propagation; (3) wave history is calculated over a regional area to determine the propagation of energy oblique to the slide axis; and (4) a high-resolution 1D <span class="hlt">model</span> is developed to <span class="hlt">accurately</span> <span class="hlt">model</span> wave breaking and the combined influence of nonlinearity and dispersion during nearshore propagation and runup. The primary source parameter that affects tsunami severity for this case study is landslide volume, with failure duration having a secondary influence. Bottom friction during propagation across the continental shelf has a strong influence on the attenuation of the tsunami during propagation. The high-resolution 1D <span class="hlt">model</span> also indicates that the tsunami undergoes nonlinear fission prior to wave breaking, generating independent, short-period waves. Wave breaking occurs approximately 40-50??km offshore where a tsunami bore is formed that persists during runup. These analyses illustrate the complex nature of landslide tsunamis, necessitating the use of detailed landslide stability/mobility <span class="hlt">models</span> and higher-order hydrodynamic <span class="hlt">models</span> to determine their hazard.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DMP.K1131M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DMP.K1131M"><span>Development and application of <span class="hlt">accurate</span> analytical <span class="hlt">models</span> for single active electron potentials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, Michelle; Jaron-Becker, Agnieszka; Becker, Andreas</p> <p>2015-05-01</p> <p>The single active electron (SAE) approximation is a theoretical <span class="hlt">model</span> frequently employed to study scenarios in which inner-shell electrons may productively be treated as frozen spectators to a physical process of interest, and <span class="hlt">accurate</span> analytical approximations for these potentials are sought as a useful simulation tool. Density function theory is often used to construct a SAE potential, requiring that a further approximation for the exchange correlation functional be enacted. In this study, we employ the Krieger, Li, and Iafrate (KLI) modification to the optimized-effective-potential (OEP) method to reduce the complexity of the problem to the straightforward solution of a system of linear equations through simple arguments regarding the behavior of the exchange-correlation potential in regions where a single orbital dominates. We employ this method for the solution of atomic and molecular potentials, and use the resultant curve to devise a systematic construction for highly <span class="hlt">accurate</span> and useful analytical approximations for several systems. Supported by the U.S. Department of Energy (Grant No. DE-FG02-09ER16103), and the U.S. National Science Foundation (Graduate Research Fellowship, Grants No. PHY-1125844 and No. PHY-1068706).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28285459','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28285459"><span>A Critical Review for Developing <span class="hlt">Accurate</span> and Dynamic Predictive <span class="hlt">Models</span> Using Machine Learning Methods in Medicine and Health Care.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alanazi, Hamdan O; Abdullah, Abdul Hanan; Qureshi, Kashif Naseer</p> <p>2017-04-01</p> <p>Recently, Artificial Intelligence (AI) has been used widely in medicine and health care sector. In machine learning, the classification or prediction is a major field of AI. Today, the study of existing predictive <span class="hlt">models</span> based on machine learning methods is extremely active. Doctors need <span class="hlt">accurate</span> predictions for the outcomes of their patients' diseases. In addition, for <span class="hlt">accurate</span> predictions, timing is another significant factor that influences treatment decisions. In this paper, existing predictive <span class="hlt">models</span> in medicine and health care have critically reviewed. Furthermore, the most famous machine learning methods have explained, and the confusion between a statistical approach and machine learning has clarified. A review of related literature reveals that the predictions of existing predictive <span class="hlt">models</span> differ even when the same dataset is used. Therefore, existing predictive <span class="hlt">models</span> are essential, and current methods must be improved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4290955','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4290955"><span>Use of Whole-Genus Genome Sequence Data To Develop a Multilocus Sequence <span class="hlt">Typing</span> Tool That <span class="hlt">Accurately</span> Identifies Yersinia Isolates to the Species and Subspecies Levels</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hall, Miquette; Chattaway, Marie A.; Reuter, Sandra; Savin, Cyril; Strauch, Eckhard; Carniel, Elisabeth; Connor, Thomas; Van Damme, Inge; Rajakaruna, Lakshani; Rajendram, Dunstan; Jenkins, Claire; Thomson, Nicholas R.</p> <p>2014-01-01</p> <p>The genus Yersinia is a large and diverse bacterial genus consisting of human-pathogenic species, a fish-pathogenic species, and a large number of environmental species. Recently, the phylogenetic and population structure of the entire genus was elucidated through the genome sequence data of 241 strains encompassing every known species in the genus. Here we report the mining of this enormous data set to create a multilocus sequence <span class="hlt">typing</span>-based scheme that can identify Yersinia strains to the species level to a level of resolution equal to that for whole-genome sequencing. Our assay is designed to be able to <span class="hlt">accurately</span> subtype the important human-pathogenic species Yersinia enterocolitica to whole-genome resolution levels. We also report the validation of the scheme on 386 strains from reference laboratory collections across Europe. We propose that the scheme is an important molecular <span class="hlt">typing</span> system to allow <span class="hlt">accurate</span> and reproducible identification of Yersinia isolates to the species level, a process often inconsistent in nonspecialist laboratories. Additionally, our assay is the most phylogenetically informative <span class="hlt">typing</span> scheme available for Y. enterocolitica. PMID:25339391</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19563225','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19563225"><span><span class="hlt">Accurately</span> tuning the charge on giant polyoxometalate <span class="hlt">type</span> Keplerates through stoichiometric interaction with cationic surfactants.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kistler, Melissa L; Patel, Komal G; Liu, Tianbo</p> <p>2009-07-07</p> <p>We report an approach of exploring the interaction between cationic surfactants and a <span class="hlt">type</span> of structurally well-defined, spherical "Keplerate" polyoxometalate (POM) macroanionic molecular clusters, {Mo72V30}, in aqueous solution. The effectiveness of the interaction can be determined by monitoring the size change of the "blackberry" supramolecular structures formed by the self-assembly of {Mo72V30} macroions, which is determined by the effective charge density on the macroions. Long-chain surfactants (CTAB and CTAT) can interact with {Mo72V30} macroions stoichiometrically and lower their charge density. Consequently, the blackberry size decreases continuously with increasing surfactant concentration in solution. On the other hand, for short-chain surfactants (e.g., OTAB), a larger fraction of surfactants exist as discrete chains in solution and do not strongly interact with the macroions. This approach shows that a controllable amount of suitable surfactants can <span class="hlt">accurately</span> tune the charge on large molecular clusters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17482218','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17482218"><span>Do dual-route <span class="hlt">models</span> <span class="hlt">accurately</span> predict reading and spelling performance in individuals with acquired alexia and agraphia?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rapcsak, Steven Z; Henry, Maya L; Teague, Sommer L; Carnahan, Susan D; Beeson, Pélagie M</p> <p>2007-06-18</p> <p>Coltheart and co-workers [Castles, A., Bates, T. C., & Coltheart, M. (2006). John Marshall and the developmental dyslexias. Aphasiology, 20, 871-892; Coltheart, M., Rastle, K., Perry, C., Langdon, R., & Ziegler, J. (2001). DRC: A dual route cascaded <span class="hlt">model</span> of visual word recognition and reading aloud. Psychological Review, 108, 204-256] have demonstrated that an equation derived from dual-route theory <span class="hlt">accurately</span> predicts reading performance in young normal readers and in children with reading impairment due to developmental dyslexia or stroke. In this paper, we present evidence that the dual-route equation and a related multiple regression <span class="hlt">model</span> also <span class="hlt">accurately</span> predict both reading and spelling performance in adult neurological patients with acquired alexia and agraphia. These findings provide empirical support for dual-route theories of written language processing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994RScI...65..374C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994RScI...65..374C"><span>An analytical <span class="hlt">model</span> for scanning electron microscope <span class="hlt">Type</span> I magnetic contrast with energy filtering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chim, W. K.</p> <p>1994-02-01</p> <p>In this article, a theoretical <span class="hlt">model</span> for <span class="hlt">type</span> I magnetic contrast calculations in the scanning electron microscope with energy filtering is presented. This <span class="hlt">model</span> uses an approximate form of the secondary electron (SE) energy distribution by Chung and Everhart [M. S. Chung and T. E. Everhart, J. Appl. Phys. 45, 707 (1974). Closed form analytical expressions for the contrast and quality factors, which take into consideration the work function and field-distance integral of the material being studied, are obtained. This analytical <span class="hlt">model</span> is compared with that of a more <span class="hlt">accurate</span> numerical <span class="hlt">model</span>. Results showed that the contrast and quality factors for the analytical <span class="hlt">model</span> differed by not more than 20% from the numerical <span class="hlt">model</span>, with the actual difference depending on the range of filtered SE energies considered. This <span class="hlt">model</span> has also been extended to the situation of a two-detector (i.e., detector A and B) configuration, in which enhanced magnetic contrast and quality factor can be obtained by operating in the ``A-B'' mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNG21A0132A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNG21A0132A"><span>When is the Anelastic Approximation a Valid <span class="hlt">Model</span> for Compressible Convection?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alboussiere, T.; Curbelo, J.; Labrosse, S.; Ricard, Y. R.; Dubuffet, F.</p> <p>2017-12-01</p> <p>Compressible convection is ubiquitous in large natural systems such Planetary atmospheres, stellar and planetary interiors. Its <span class="hlt">modelling</span> is notoriously more difficult than the case when the <span class="hlt">Boussinesq</span> approximation applies. One reason for that difficulty has been put forward by Ogura and Phillips (1961): the compressible equations generate sound waves with very short time scales which need to be resolved. This is why they introduced an anelastic <span class="hlt">model</span>, based on an expansion of the solution around an isentropic hydrostatic profile. How <span class="hlt">accurate</span> is that anelastic <span class="hlt">model</span>? What are the conditions for its validity? To answer these questions, we have developed a numerical <span class="hlt">model</span> for the full set of compressible equations and compared its solutions with those of the corresponding anelastic <span class="hlt">model</span>. We considered a simple rectangular 2D Rayleigh-Bénard configuration and decided to restrict the analysis to infinite Prandtl numbers. This choice is valid for convection in the mantles of rocky planets, but more importantly lead to a zero Mach number. So we got rid of the question of the interference of acoustic waves with convection. In that simplified context, we used the entropy balances (that of the full set of equations and that of the anelastic <span class="hlt">model</span>) to investigate the differences between exact and anelastic solutions. We found that the validity of the anelastic <span class="hlt">model</span> is dictated by two conditions: first, the superadiabatic temperature difference must be small compared with the adiabatic temperature difference (as expected) ɛ = Δ TSA / delta Ta << 1, and secondly that the product of ɛ with the Nusselt number must be small.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1208736-accurate-modeling-inversion-electrical-resistivity-data-presence-metallic-infrastructure-known-location-dimension','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1208736-accurate-modeling-inversion-electrical-resistivity-data-presence-metallic-infrastructure-known-location-dimension"><span><span class="hlt">Accurate</span> <span class="hlt">modeling</span> and inversion of electrical resistivity data in the presence of metallic infrastructure with known location and dimension</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Johnson, Timothy C.; Wellman, Dawn M.</p> <p>2015-06-26</p> <p>Electrical resistivity tomography (ERT) has been widely used in environmental applications to study processes associated with subsurface contaminants and contaminant remediation. Anthropogenic alterations in subsurface electrical conductivity associated with contamination often originate from highly industrialized areas with significant amounts of buried metallic infrastructure. The deleterious influence of such infrastructure on imaging results generally limits the utility of ERT where it might otherwise prove useful for subsurface investigation and monitoring. In this manuscript we present a method of <span class="hlt">accurately</span> <span class="hlt">modeling</span> the effects of buried conductive infrastructure within the forward <span class="hlt">modeling</span> algorithm, thereby removing them from the inversion results. The method ismore » implemented in parallel using immersed interface boundary conditions, whereby the global solution is reconstructed from a series of well-conditioned partial solutions. Forward <span class="hlt">modeling</span> accuracy is demonstrated by comparison with analytic solutions. Synthetic imaging examples are used to investigate imaging capabilities within a subsurface containing electrically conductive buried tanks, transfer piping, and well casing, using both well casings and vertical electrode arrays as current sources and potential measurement electrodes. Results show that, although <span class="hlt">accurate</span> infrastructure <span class="hlt">modeling</span> removes the dominating influence of buried metallic features, the presence of metallic infrastructure degrades imaging resolution compared to standard ERT imaging. However, <span class="hlt">accurate</span> imaging results may be obtained if electrodes are appropriately located.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3722289','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3722289"><span>An Integrated Tool to Study MHC Region: <span class="hlt">Accurate</span> SNV Detection and HLA Genes <span class="hlt">Typing</span> in Human MHC Region Using Targeted High-Throughput Sequencing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Xiao; Xu, Yinyin; Liang, Dequan; Gao, Peng; Sun, Yepeng; Gifford, Benjamin; D’Ascenzo, Mark; Liu, Xiaomin; Tellier, Laurent C. A. M.; Yang, Fang; Tong, Xin; Chen, Dan; Zheng, Jing; Li, Weiyang; Richmond, Todd; Xu, Xun; Wang, Jun; Li, Yingrui</p> <p>2013-01-01</p> <p>The major histocompatibility complex (MHC) is one of the most variable and gene-dense regions of the human genome. Most studies of the MHC, and associated regions, focus on minor variants and HLA <span class="hlt">typing</span>, many of which have been demonstrated to be associated with human disease susceptibility and metabolic pathways. However, the detection of variants in the MHC region, and diagnostic HLA <span class="hlt">typing</span>, still lacks a coherent, standardized, cost effective and high coverage protocol of clinical quality and reliability. In this paper, we presented such a method for the <span class="hlt">accurate</span> detection of minor variants and HLA <span class="hlt">types</span> in the human MHC region, using high-throughput, high-coverage sequencing of target regions. A probe set was designed to template upon the 8 annotated human MHC haplotypes, and to encompass the 5 megabases (Mb) of the extended MHC region. We deployed our probes upon three, genetically diverse human samples for probe set evaluation, and sequencing data show that ∼97% of the MHC region, and over 99% of the genes in MHC region, are covered with sufficient depth and good evenness. 98% of genotypes called by this capture sequencing prove consistent with established HapMap genotypes. We have concurrently developed a one-step pipeline for calling any HLA <span class="hlt">type</span> referenced in the IMGT/HLA database from this target capture sequencing data, which shows over 96% <span class="hlt">typing</span> accuracy when deployed at 4 digital resolution. This cost-effective and highly <span class="hlt">accurate</span> approach for variant detection and HLA <span class="hlt">typing</span> in the MHC region may lend further insight into immune-mediated diseases studies, and may find clinical utility in transplantation medicine research. This one-step pipeline is released for general evaluation and use by the scientific community. PMID:23894464</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93o5123B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93o5123B"><span>Efficient and <span class="hlt">accurate</span> approach to <span class="hlt">modeling</span> the microstructure and defect properties of LaCoO3</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buckeridge, J.; Taylor, F. H.; Catlow, C. R. A.</p> <p>2016-04-01</p> <p>Complex perovskite oxides are promising materials for cathode layers in solid oxide fuel cells. Such materials have intricate electronic, magnetic, and crystalline structures that prove challenging to <span class="hlt">model</span> <span class="hlt">accurately</span>. We analyze a wide range of standard density functional theory approaches to <span class="hlt">modeling</span> a highly promising system, the perovskite LaCoO3, focusing on optimizing the Hubbard U parameter to treat the self-interaction of the B-site cation's d states, in order to determine the most appropriate method to study defect formation and the effect of spin on local structure. By calculating structural and electronic properties for different magnetic states we determine that U =4 eV for Co in LaCoO3 agrees best with available experiments. We demonstrate that the generalized gradient approximation (PBEsol +U ) is most appropriate for studying structure versus spin state, while the local density approximation (LDA +U ) is most appropriate for determining <span class="hlt">accurate</span> energetics for defect properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JChPh.132p4115T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JChPh.132p4115T"><span><span class="hlt">Accurate</span> calculation and <span class="hlt">modeling</span> of the adiabatic connection in density functional theory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Teale, A. M.; Coriani, S.; Helgaker, T.</p> <p>2010-04-01</p> <p> AC. When parametrized in terms of the same input data, the AC-CI <span class="hlt">model</span> offers improved performance over the corresponding AC-D <span class="hlt">model</span>, which is shown to be the lowest-order contribution to the AC-CI <span class="hlt">model</span>. The utility of the <span class="hlt">accurately</span> calculated AC curves for the analysis of standard density functionals is demonstrated for the BLYP exchange-correlation functional and the interaction-strength-interpolation (ISI) <span class="hlt">model</span> AC integrand. From the results of this analysis, we investigate the performance of our proposed two-parameter AC-D and AC-CI <span class="hlt">models</span> when a simple density functional for the AC at infinite interaction strength is employed in place of information at the fully interacting point. The resulting two-parameter correlation functionals offer a qualitatively correct behavior of the AC integrand with much improved accuracy over previous attempts. The AC integrands in the present work are recommended as a basis for further work, generating functionals that avoid spurious error cancellations between exchange and correlation energies and give good accuracy for the range of densities and <span class="hlt">types</span> of correlation contained in the systems studied here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26344543','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26344543"><span><span class="hlt">Accurate</span> <span class="hlt">Modeling</span> of Dark-Field Scattering Spectra of Plasmonic Nanostructures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiang, Liyong; Yin, Tingting; Dong, Zhaogang; Liao, Mingyi; Tan, Shawn J; Goh, Xiao Ming; Allioux, David; Hu, Hailong; Li, Xiangyin; Yang, Joel K W; Shen, Zexiang</p> <p>2015-10-27</p> <p>Dark-field microscopy is a widely used tool for measuring the optical resonance of plasmonic nanostructures. However, current numerical methods for simulating the dark-field scattering spectra were carried out with plane wave illumination either at normal incidence or at an oblique angle from one direction. In actual experiments, light is focused onto the sample through an annular ring within a range of glancing angles. In this paper, we present a theoretical <span class="hlt">model</span> capable of <span class="hlt">accurately</span> simulating the dark-field light source with an annular ring. Simulations correctly reproduce a counterintuitive blue shift in the scattering spectra from gold nanodisks with a diameter beyond 140 nm. We believe that our proposed simulation method can be potentially applied as a general tool capable of simulating the dark-field scattering spectra of plasmonic nanostructures as well as other dielectric nanostructures with sizes beyond the quasi-static limit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1160338','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1160338"><span>Evaluation of INL Supplied MOOSE/OSPREY <span class="hlt">Model</span>: <span class="hlt">Modeling</span> Water Adsorption on <span class="hlt">Type</span> 3A Molecular Sieve</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Pompilio, L. M.; DePaoli, D. W.; Spencer, B. B.</p> <p></p> <p>The purpose of this study was to evaluate Idaho National Lab’s Multiphysics Object-Oriented Simulation Environment (MOOSE) software in <span class="hlt">modeling</span> the adsorption of water onto <span class="hlt">type</span> 3A molecular sieve (3AMS). MOOSE can be thought-of as a computing framework within which applications <span class="hlt">modeling</span> specific coupled-phenomena can be developed and run. The application titled Off-gas SeParation and REcoverY (OSPREY) has been developed to <span class="hlt">model</span> gas sorption in packed columns. The sorbate breakthrough curve calculated by MOOSE/OSPREY was compared to results previously obtained in the deep bed hydration tests conducted at Oak Ridge National Laboratory. The coding framework permits selection of various options, whenmore » they exist, for <span class="hlt">modeling</span> a process. For example, the OSPREY module includes options to <span class="hlt">model</span> the adsorption equilibrium with a Langmuir <span class="hlt">model</span> or a generalized statistical thermodynamic adsorption (GSTA) <span class="hlt">model</span>. The vapor solid equilibria and the operating conditions of the process (e.g., gas phase concentration) are required to calculate the concentration gradient driving the mass transfer between phases. Both the Langmuir and GSTA <span class="hlt">models</span> were tested in this evaluation. Input variables were either known from experimental conditions, or were available (e.g., density) or were estimated (e.g., thermal conductivity of sorbent) from the literature. Variables were considered independent of time, i.e., rather than having a mass transfer coefficient that varied with time or position in the bed, the parameter was set to remain constant. The calculated results did not coincide with data from laboratory tests. The <span class="hlt">model</span> <span class="hlt">accurately</span> estimated the number of bed volumes processed for the given operating parameters, but breakthrough times were not <span class="hlt">accurately</span> predicted, varying 50% or more from the data. The shape of the breakthrough curves also differed from the experimental data, indicating a much wider sorption band. <span class="hlt">Model</span> modifications are needed to improve its utility and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910063653&hterms=equations+quadratics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dequations%2Bquadratics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910063653&hterms=equations+quadratics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dequations%2Bquadratics"><span>Frontogenesis driven by horizontally quadratic distributions of density</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jacqmin, David</p> <p>1991-01-01</p> <p>Attention is given to the quadratic density distribution in a channel, which has been established by Simpson and Linden to be the simplest case of the horizontally nonlinear distribution of fluid density required for the production of frontogenesis. The porous-media and <span class="hlt">Boussinesq</span> flow <span class="hlt">models</span> are examined, and their evolution equations are reduced to one-dimensional systems. While both the porous-media and the inviscid/nondiffusive <span class="hlt">Boussinesq</span> systems exhibit classic frontogenesis behavior, the viscous <span class="hlt">Boussinesq</span> system exhibits a more complex behavior: boundary-layer effects force frontogenesis away from the lower boundary, and at late times the steepest density gradients are close to mid-channel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9797E..0TA','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9797E..0TA"><span>A predictive <span class="hlt">model</span> for biomimetic plate <span class="hlt">type</span> broadband frequency sensor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahmed, Riaz U.; Banerjee, Sourav</p> <p>2016-04-01</p> <p>In this work, predictive <span class="hlt">model</span> for a bio-inspired broadband frequency sensor is developed. Broadband frequency sensing is essential in many domains of science and technology. One great example of such sensor is human cochlea, where it senses a frequency band of 20 Hz to 20 KHz. Developing broadband sensor adopting the physics of human cochlea has found tremendous interest in recent years. Although few experimental studies have been reported, a true predictive <span class="hlt">model</span> to design such sensors is missing. A predictive <span class="hlt">model</span> is utmost necessary for <span class="hlt">accurate</span> design of selective broadband sensors that are capable of sensing very selective band of frequencies. Hence, in this study, we proposed a novel predictive <span class="hlt">model</span> for the cochlea-inspired broadband sensor, aiming to select the frequency band and <span class="hlt">model</span> parameters predictively. Tapered plate geometry is considered mimicking the real shape of the basilar membrane in the human cochlea. The predictive <span class="hlt">model</span> is intended to develop flexible enough that can be employed in a wide variety of scientific domains. To do that, the predictive <span class="hlt">model</span> is developed in such a way that, it can not only handle homogeneous but also any functionally graded <span class="hlt">model</span> parameters. Additionally, the predictive <span class="hlt">model</span> is capable of managing various <span class="hlt">types</span> of boundary conditions. It has been found that, using the homogeneous <span class="hlt">model</span> parameters, it is possible to sense a specific frequency band from a specific portion (B) of the <span class="hlt">model</span> length (L). It is also possible to alter the attributes of `B' using functionally graded <span class="hlt">model</span> parameters, which confirms the predictive frequency selection ability of the developed <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005OcMod...9...71W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005OcMod...9...71W"><span>A non-hydrostatic flat-bottom ocean <span class="hlt">model</span> entirely based on Fourier expansion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wirth, A.</p> <p>2005-01-01</p> <p>We show how to implement free-slip and no-slip boundary conditions in a three dimensional <span class="hlt">Boussinesq</span> flat-bottom ocean <span class="hlt">model</span> based on Fourier expansion. Our method is inspired by the immersed or virtual boundary technique in which the effect of boundaries on the flow field is <span class="hlt">modeled</span> by a virtual force field. Our method, however, explicitly depletes the velocity on the boundary induced by the pressure, while at the same time respecting the incompressibility of the flow field. Spurious spatial oscillations remain at a negligible level in the simulated flow field when using our technique and no filtering of the flow field is necessary. We furthermore show that by using the method presented here the residual velocities at the boundaries are easily reduced to a negligible value. This stands in contradistinction to previous calculations using the immersed or virtual boundary technique. The efficiency is demonstrated by simulating a Rayleigh impulsive flow, for which the time evolution of the simulated flow is compared to an analytic solution, and a three dimensional <span class="hlt">Boussinesq</span> simulation of ocean convection. The second instance is taken form a well studied oceanographic context: A free slip boundary condition is applied on the upper surface, the <span class="hlt">modeled</span> sea surface, and a no-slip boundary condition to the lower boundary, the <span class="hlt">modeled</span> ocean floor. Convergence properties of the method are investigated by solving a two dimensional stationary problem at different spatial resolutions. The work presented here is restricted to a flat ocean floor. Extensions of our method to ocean <span class="hlt">models</span> with a realistic topography are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28777447','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28777447"><span>Technical Note: Using experimentally determined proton spot scanning timing parameters to <span class="hlt">accurately</span> <span class="hlt">model</span> beam delivery time.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shen, Jiajian; Tryggestad, Erik; Younkin, James E; Keole, Sameer R; Furutani, Keith M; Kang, Yixiu; Herman, Michael G; Bues, Martin</p> <p>2017-10-01</p> <p>To <span class="hlt">accurately</span> <span class="hlt">model</span> the beam delivery time (BDT) for a synchrotron-based proton spot scanning system using experimentally determined beam parameters. A <span class="hlt">model</span> to simulate the proton spot delivery sequences was constructed, and BDT was calculated by summing times for layer switch, spot switch, and spot delivery. Test plans were designed to isolate and quantify the relevant beam parameters in the operation cycle of the proton beam therapy delivery system. These parameters included the layer switch time, magnet preparation and verification time, average beam scanning speeds in x- and y-directions, proton spill rate, and maximum charge and maximum extraction time for each spill. The experimentally determined parameters, as well as the nominal values initially provided by the vendor, served as inputs to the <span class="hlt">model</span> to predict BDTs for 602 clinical proton beam deliveries. The calculated BDTs (T BDT ) were compared with the BDTs recorded in the treatment delivery log files (T Log ): ∆t = T Log -T BDT . The experimentally determined average layer switch time for all 97 energies was 1.91 s (ranging from 1.9 to 2.0 s for beam energies from 71.3 to 228.8 MeV), average magnet preparation and verification time was 1.93 ms, the average scanning speeds were 5.9 m/s in x-direction and 19.3 m/s in y-direction, the proton spill rate was 8.7 MU/s, and the maximum proton charge available for one acceleration is 2.0 ± 0.4 nC. Some of the measured parameters differed from the nominal values provided by the vendor. The calculated BDTs using experimentally determined parameters matched the recorded BDTs of 602 beam deliveries (∆t = -0.49 ± 1.44 s), which were significantly more <span class="hlt">accurate</span> than BDTs calculated using nominal timing parameters (∆t = -7.48 ± 6.97 s). An <span class="hlt">accurate</span> <span class="hlt">model</span> for BDT prediction was achieved by using the experimentally determined proton beam therapy delivery parameters, which may be useful in <span class="hlt">modeling</span> the interplay effect and patient throughput. The <span class="hlt">model</span> may</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28605711','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28605711"><span>Numerical <span class="hlt">modelling</span> of flow through foam's node.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anazadehsayed, Abdolhamid; Rezaee, Nastaran; Naser, Jamal</p> <p>2017-10-15</p> <p>In this work, for the first time, a three-dimensional <span class="hlt">model</span> to describe the dynamics of flow through geometric Plateau border and node components of foam is presented. The <span class="hlt">model</span> involves a microscopic-scale structure of one interior node and four Plateau borders with an angle of 109.5 from each other. The majority of the surfaces in the <span class="hlt">model</span> make a liquid-gas interface where the boundary condition of stress balance between the surface and bulk is applied. The three-dimensional Navier-Stoke equation, along with continuity equation, is solved using the finite volume approach. The numerical results are validated against the available experimental results for the flow velocity and resistance in the interior nodes and Plateau borders. A qualitative illustration of flow in a node in different orientations is shown. The scaled resistance against the flow for different liquid-gas interface mobility is studied and the geometrical characteristics of the node and Plateau border components of the system are compared to investigate the Plateau border and node dominated flow regimes numerically. The findings show the values of the resistance in each component, in addition to the exact point where the flow regimes switch. Furthermore, a more <span class="hlt">accurate</span> effect of the liquid-gas interface on the foam flow, particularly in the presence of a node in the foam network is obtained. The comparison of the available numerical results with our numerical results shows that the velocity of the node-PB system is lower than the velocity of single PB system for mobile interfaces. That is owing to the fact that despite the more relaxed geometrical structure of the node, constraining effect of merging and mixing of flow and increased viscous damping in the node component result in the node-dominated regime. Moreover, we obtain an <span class="hlt">accurate</span> updated correlation for the dependence of the scaled average velocity of the node-Plateau border system on the liquid-gas interface mobility described by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20046650','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20046650"><span>Physical activity into the meal glucose-insulin <span class="hlt">model</span> of <span class="hlt">type</span> 1 diabetes: in silico studies.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Man, Chiara Dalla; Breton, Marc D; Cobelli, Claudio</p> <p>2009-01-01</p> <p>A simulation <span class="hlt">model</span> of a glucose-insulin system accounting for physical activity is needed to reliably simulate normal life conditions, thus accelerating the development of an artificial pancreas. In fact, exercise causes a transient increase of insulin action and may lead to hypoglycemia. However, physical activity is difficult to <span class="hlt">model</span>. In the past, it was described indirectly as a rise in insulin. Recently, a new parsimonious <span class="hlt">model</span> of exercise effect on glucose homeostasis has been proposed that links the change in insulin action and glucose effectiveness to heart rate (HR). The aim of this study was to plug this exercise <span class="hlt">model</span> into our recently proposed large-scale simulation <span class="hlt">model</span> of glucose metabolism in <span class="hlt">type</span> 1 diabetes to better describe normal life conditions. The exercise <span class="hlt">model</span> describes changes in glucose-insulin dynamics in two phases: a rapid on-and-off change in insulin-independent glucose clearance and a rapid-on/slow-off change in insulin sensitivity. Three candidate <span class="hlt">models</span> of glucose effectiveness and insulin sensitivity as a function of HR have been considered, both during exercise and recovery after exercise. By incorporating these three <span class="hlt">models</span> into the <span class="hlt">type</span> 1 diabetes <span class="hlt">model</span>, we simulated different levels (from mild to moderate) and duration of exercise (15 and 30 minutes), both in steady-state (e.g., during euglycemic-hyperinsulinemic clamp) and in nonsteady state (e.g., after a meal) conditions. One candidate exercise <span class="hlt">model</span> was selected as the most reliable. A <span class="hlt">type</span> 1 diabetes <span class="hlt">model</span> also describing physical activity is proposed. The <span class="hlt">model</span> represents a step forward to <span class="hlt">accurately</span> describe glucose homeostasis in normal life conditions; however, further studies are needed to validate it against data. © Diabetes Technology Society</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDQ29011X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDQ29011X"><span>A new algebraic turbulence <span class="hlt">model</span> for <span class="hlt">accurate</span> description of airfoil flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiao, Meng-Juan; She, Zhen-Su</p> <p>2017-11-01</p> <p>We report a new algebraic turbulence <span class="hlt">model</span> (SED-SL) based on the SED theory, a symmetry-based approach to quantifying wall turbulence. The <span class="hlt">model</span> specifies a multi-layer profile of a stress length (SL) function in both the streamwise and wall-normal directions, which thus define the eddy viscosity in the RANS equation (e.g. a zero-equation <span class="hlt">model</span>). After a successful simulation of flat plate flow (APS meeting, 2016), we report here further applications of the <span class="hlt">model</span> to the flow around airfoil, with significant improvement of the prediction accuracy of the lift (CL) and drag (CD) coefficients compared to other popular <span class="hlt">models</span> (e.g. BL, SA, etc.). Two airfoils, namely RAE2822 airfoil and NACA0012 airfoil, are computed for over 50 cases. The results are compared to experimental data from AGARD report, which shows deviations of CL bounded within 2%, and CD within 2 counts (10-4) for RAE2822 and 6 counts for NACA0012 respectively (under a systematic adjustment of the flow conditions). In all these calculations, only one parameter (proportional to the Karmen constant) shows slight variation with Mach number. The most remarkable outcome is, for the first time, the <span class="hlt">accurate</span> prediction of the drag coefficient. The other interesting outcome is the physical interpretation of the multi-layer parameters: they specify the corresponding multi-layer structure of turbulent boundary layer; when used together with simulation data, the SED-SL enables one to extract physical information from empirical data, and to understand the variation of the turbulent boundary layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28505151','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28505151"><span>Mixture <span class="hlt">models</span> reveal multiple positional bias <span class="hlt">types</span> in RNA-Seq data and lead to <span class="hlt">accurate</span> transcript concentration estimates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tuerk, Andreas; Wiktorin, Gregor; Güler, Serhat</p> <p>2017-05-01</p> <p>Accuracy of transcript quantification with RNA-Seq is negatively affected by positional fragment bias. This article introduces Mix2 (rd. "mixquare"), a transcript quantification method which uses a mixture of probability distributions to <span class="hlt">model</span> and thereby neutralize the effects of positional fragment bias. The parameters of Mix2 are trained by Expectation Maximization resulting in simultaneous transcript abundance and bias estimates. We compare Mix2 to Cufflinks, RSEM, eXpress and PennSeq; state-of-the-art quantification methods implementing some form of bias correction. On four synthetic biases we show that the accuracy of Mix2 overall exceeds the accuracy of the other methods and that its bias estimates converge to the correct solution. We further evaluate Mix2 on real RNA-Seq data from the Microarray and Sequencing Quality Control (MAQC, SEQC) Consortia. On MAQC data, Mix2 achieves improved correlation to qPCR measurements with a relative increase in R2 between 4% and 50%. Mix2 also yields repeatable concentration estimates across technical replicates with a relative increase in R2 between 8% and 47% and reduced standard deviation across the full concentration range. We further observe more <span class="hlt">accurate</span> detection of differential expression with a relative increase in true positives between 74% and 378% for 5% false positives. In addition, Mix2 reveals 5 dominant biases in MAQC data deviating from the common assumption of a uniform fragment distribution. On SEQC data, Mix2 yields higher consistency between measured and predicted concentration ratios. A relative error of 20% or less is obtained for 51% of transcripts by Mix2, 40% of transcripts by Cufflinks and RSEM and 30% by eXpress. Titration order consistency is correct for 47% of transcripts for Mix2, 41% for Cufflinks and RSEM and 34% for eXpress. We, further, observe improved repeatability across laboratory sites with a relative increase in R2 between 8% and 44% and reduced standard deviation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24564209','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24564209"><span>Towards <span class="hlt">accurate</span> <span class="hlt">modeling</span> of noncovalent interactions for protein rigidity analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fox, Naomi; Streinu, Ileana</p> <p>2013-01-01</p> <p>Protein rigidity analysis is an efficient computational method for extracting flexibility information from static, X-ray crystallography protein data. Atoms and bonds are <span class="hlt">modeled</span> as a mechanical structure and analyzed with a fast graph-based algorithm, producing a decomposition of the flexible molecule into interconnected rigid clusters. The result depends critically on noncovalent atomic interactions, primarily on how hydrogen bonds and hydrophobic interactions are computed and <span class="hlt">modeled</span>. Ongoing research points to the stringent need for benchmarking rigidity analysis software systems, towards the goal of increasing their accuracy and validating their results, either against each other and against biologically relevant (functional) parameters. We propose two new methods for <span class="hlt">modeling</span> hydrogen bonds and hydrophobic interactions that more <span class="hlt">accurately</span> reflect a mechanical <span class="hlt">model</span>, without being computationally more intensive. We evaluate them using a novel scoring method, based on the B-cubed score from the information retrieval literature, which measures how well two cluster decompositions match. To evaluate the <span class="hlt">modeling</span> accuracy of KINARI, our pebble-game rigidity analysis system, we use a benchmark data set of 20 proteins, each with multiple distinct conformations deposited in the Protein Data Bank. Cluster decompositions for them were previously determined with the RigidFinder method from Gerstein's lab and validated against experimental data. When KINARI's default tuning parameters are used, an improvement of the B-cubed score over a crude baseline is observed in 30% of this data. With our new <span class="hlt">modeling</span> options, improvements were observed in over 70% of the proteins in this data set. We investigate the sensitivity of the cluster decomposition score with case studies on pyruvate phosphate dikinase and calmodulin. To substantially improve the accuracy of protein rigidity analysis systems, thorough benchmarking must be performed on all current systems and future</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3817810','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3817810"><span>Towards <span class="hlt">accurate</span> <span class="hlt">modeling</span> of noncovalent interactions for protein rigidity analysis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background Protein rigidity analysis is an efficient computational method for extracting flexibility information from static, X-ray crystallography protein data. Atoms and bonds are <span class="hlt">modeled</span> as a mechanical structure and analyzed with a fast graph-based algorithm, producing a decomposition of the flexible molecule into interconnected rigid clusters. The result depends critically on noncovalent atomic interactions, primarily on how hydrogen bonds and hydrophobic interactions are computed and <span class="hlt">modeled</span>. Ongoing research points to the stringent need for benchmarking rigidity analysis software systems, towards the goal of increasing their accuracy and validating their results, either against each other and against biologically relevant (functional) parameters. We propose two new methods for <span class="hlt">modeling</span> hydrogen bonds and hydrophobic interactions that more <span class="hlt">accurately</span> reflect a mechanical <span class="hlt">model</span>, without being computationally more intensive. We evaluate them using a novel scoring method, based on the B-cubed score from the information retrieval literature, which measures how well two cluster decompositions match. Results To evaluate the <span class="hlt">modeling</span> accuracy of KINARI, our pebble-game rigidity analysis system, we use a benchmark data set of 20 proteins, each with multiple distinct conformations deposited in the Protein Data Bank. Cluster decompositions for them were previously determined with the RigidFinder method from Gerstein's lab and validated against experimental data. When KINARI's default tuning parameters are used, an improvement of the B-cubed score over a crude baseline is observed in 30% of this data. With our new <span class="hlt">modeling</span> options, improvements were observed in over 70% of the proteins in this data set. We investigate the sensitivity of the cluster decomposition score with case studies on pyruvate phosphate dikinase and calmodulin. Conclusion To substantially improve the accuracy of protein rigidity analysis systems, thorough benchmarking must be performed on all</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ClDy...32..251T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ClDy...32..251T"><span>A more <span class="hlt">accurate</span> scheme for calculating Earth's skin temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsuang, Ben-Jei; Tu, Chia-Ying; Tsai, Jeng-Lin; Dracup, John A.; Arpe, Klaus; Meyers, Tilden</p> <p>2009-02-01</p> <p>The theoretical framework of the vertical discretization of a ground column for calculating Earth’s skin temperature is presented. The suggested discretization is derived from the evenly heat-content discretization with the optimal effective thickness for layer-temperature simulation. For the same level number, the suggested discretization is more <span class="hlt">accurate</span> in skin temperature as well as surface ground heat flux simulations than those used in some state-of-the-art <span class="hlt">models</span>. A proposed scheme (“op(3,2,0)”) can reduce the normalized root-mean-square error (or RMSE/STD ratio) of the calculated surface ground heat flux of a cropland site significantly to 2% (or 0.9 W m-2), from 11% (or 5 W m-2) by a 5-layer scheme used in ECMWF, from 19% (or 8 W m-2) by a 5-layer scheme used in ECHAM, and from 74% (or 32 W m-2) by a single-layer scheme used in the UCLA GCM. Better accuracy can be achieved by including more layers to the vertical discretization. Similar improvements are expected for other locations with different land <span class="hlt">types</span> since the numerical error is inherited into the <span class="hlt">models</span> for all the land <span class="hlt">types</span>. The proposed scheme can be easily implemented into state-of-the-art climate <span class="hlt">models</span> for the temperature simulation of snow, ice and soil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040090202&hterms=Roswell&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DRoswell','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040090202&hterms=Roswell&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DRoswell"><span>Cumulative atomic multipole moments complement any atomic charge <span class="hlt">model</span> to obtain more <span class="hlt">accurate</span> electrostatic properties</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sokalski, W. A.; Shibata, M.; Ornstein, R. L.; Rein, R.</p> <p>1992-01-01</p> <p>The quality of several atomic charge <span class="hlt">models</span> based on different definitions has been analyzed using cumulative atomic multipole moments (CAMM). This formalism can generate higher atomic moments starting from any atomic charges, while preserving the corresponding molecular moments. The atomic charge contribution to the higher molecular moments, as well as to the electrostatic potentials, has been examined for CO and HCN molecules at several different levels of theory. The results clearly show that the electrostatic potential obtained from CAMM expansion is convergent up to R-5 term for all atomic charge <span class="hlt">models</span> used. This illustrates that higher atomic moments can be used to supplement any atomic charge <span class="hlt">model</span> to obtain more <span class="hlt">accurate</span> description of electrostatic properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...579A..53O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...579A..53O"><span>Mg line formation in late-<span class="hlt">type</span> stellar atmospheres. I. The <span class="hlt">model</span> atom</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Osorio, Y.; Barklem, P. S.; Lind, K.; Belyaev, A. K.; Spielfiedel, A.; Guitou, M.; Feautrier, N.</p> <p>2015-07-01</p> <p>Context. Magnesium is an element of significant astrophysical importance, often traced in late-<span class="hlt">type</span> stars using lines of neutral magnesium, which is expected to be subject to departures from local thermodynamic equilibrium (LTE). The importance of Mg , together with the unique range of spectral features in late-<span class="hlt">type</span> stars probing different parts of the atom, as well as its relative simplicity from an atomic physics point of view, makes it a prime target and test bed for detailed ab initio non-LTE <span class="hlt">modelling</span> in stellar atmospheres. Previous non-LTE <span class="hlt">modelling</span> of spectral line formation has, however, been subject to uncertainties due to lack of <span class="hlt">accurate</span> data for inelastic collisions with electrons and hydrogen atoms. Aims: In this paper we build and test a Mg <span class="hlt">model</span> atom for spectral line formation in late-<span class="hlt">type</span> stars with new or recent inelastic collision data and no associated free parameters. We aim to reduce these uncertainties and thereby improve the accuracy of Mg non-LTE <span class="hlt">modelling</span> in late-<span class="hlt">type</span> stars. Methods: For the low-lying states of Mg i, electron collision data were calculated using the R-matrix method. Hydrogen collision data, including charge transfer processes, were taken from recent calculations by some of us. Calculations for collisional broadening by neutral hydrogen were also performed where data were missing. These calculations, together with data from the literature, were used to build a <span class="hlt">model</span> atom. This <span class="hlt">model</span> was then employed in the context of standard non-LTE <span class="hlt">modelling</span> in 1D (including average 3D) <span class="hlt">model</span> atmospheres in a small set of stellar atmosphere <span class="hlt">models</span>. First, the <span class="hlt">modelling</span> was tested by comparisons with observed spectra of benchmark stars with well-known parameters. Second, the spectral line behaviour and uncertainties were explored by extensive experiments in which sets of collisional data were changed or removed. Results: The <span class="hlt">modelled</span> spectra agree well with observed spectra from benchmark stars, showing much better agreement with line</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10134E..1ZH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10134E..1ZH"><span>Radiomics biomarkers for <span class="hlt">accurate</span> tumor progression prediction of oropharyngeal cancer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hadjiiski, Lubomir; Chan, Heang-Ping; Cha, Kenny H.; Srinivasan, Ashok; Wei, Jun; Zhou, Chuan; Prince, Mark; Papagerakis, Silvana</p> <p>2017-03-01</p> <p><span class="hlt">Accurate</span> tumor progression prediction for oropharyngeal cancers is crucial for identifying patients who would best be treated with optimized treatment and therefore minimize the risk of under- or over-treatment. An objective decision support system that can merge the available radiomics, histopathologic and molecular biomarkers in a predictive <span class="hlt">model</span> based on statistical outcomes of previous cases and machine learning may assist clinicians in making more <span class="hlt">accurate</span> assessment of oropharyngeal tumor progression. In this study, we evaluated the feasibility of developing individual and combined predictive <span class="hlt">models</span> based on quantitative image analysis from radiomics, histopathology and molecular biomarkers for oropharyngeal tumor progression prediction. With IRB approval, 31, 84, and 127 patients with head and neck CT (CT-HN), tumor tissue microarrays (TMAs) and molecular biomarker expressions, respectively, were collected. For 8 of the patients all 3 <span class="hlt">types</span> of biomarkers were available and they were sequestered in a test set. The CT-HN lesions were automatically segmented using our level sets based method. Morphological, texture and molecular based features were extracted from CT-HN and TMA images, and selected features were merged by a neural network. The classification accuracy was quantified using the area under the ROC curve (AUC). Test AUCs of 0.87, 0.74, and 0.71 were obtained with the individual predictive <span class="hlt">models</span> based on radiomics, histopathologic, and molecular features, respectively. Combining the radiomics and molecular <span class="hlt">models</span> increased the test AUC to 0.90. Combining all 3 <span class="hlt">models</span> increased the test AUC further to 0.94. This preliminary study demonstrates that the individual domains of biomarkers are useful and the integrated multi-domain approach is most promising for tumor progression prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGP31A..08G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGP31A..08G"><span>Saturn Dynamo <span class="hlt">Model</span> (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glatzmaier, G. A.</p> <p>2010-12-01</p> <p>There has been considerable interest during the past few years about the banded zonal winds and global magnetic field on Saturn (and Jupiter). Questions regarding the depth to which the intense winds extend below the surface and the role they play in maintaining the dynamo continue to be debated. The <span class="hlt">types</span> of computer <span class="hlt">models</span> employed to address these questions fall into two main classes: general circulation <span class="hlt">models</span> (GCMs) based on hydrostatic shallow-water assumptions from the atmospheric and ocean <span class="hlt">modeling</span> communities and global non-hydrostatic deep convection <span class="hlt">models</span> from the geodynamo and solar dynamo communities. The latter class can be further divided into <span class="hlt">Boussinesq</span> <span class="hlt">models</span>, which do not account for density stratification, and anelastic <span class="hlt">models</span>, which do. Recent efforts to convert GCMs to deep circulation anelastic <span class="hlt">models</span> have succeeded in producing fluid flows similar to those obtained from the original deep convection anelastic <span class="hlt">models</span>. We describe results from one of the original anelastic convective dynamo simulations and compare them to a recent anelastic dynamo benchmark for giant gas planets. This benchmark is based on a polytropic reference state that spans five density scale heights with a radius and rotation rate similar to those of our solar system gas giants. The resulting magnetic Reynolds number is about 3000. Better spatial resolution will be required to produce more realistic predictions that capture the effects of both the density and electrical conductivity stratifications and include enough of the turbulent kinetic energy spectrum. Important additional physics may also be needed in the <span class="hlt">models</span>. However, the basic <span class="hlt">models</span> used in all simulation studies of the global dynamics of giant planets will hopefully first be validated by doing these simpler benchmarks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009Th%26Ae..16..469P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009Th%26Ae..16..469P"><span><span class="hlt">Modelling</span> of convective processes during the Bridgman growth of poly-silicon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Popov, V. N.</p> <p>2009-09-01</p> <p>An original 3D <span class="hlt">model</span> was used to numerically examine convective heat-and-mass transfer processes in the melt during the growth of polycrystalline silicon in vertical Bridgman configuration. The flow in the liquid was <span class="hlt">modelled</span> using the Navier — Stokes equations in the <span class="hlt">Boussinesq</span> approximation. The distribution of dissolved impurities was determined by solving the convective diffusion equation. The effects due to non-uniform heating of the lateral wall of the vessel and due to the shape of the crystallization front on the structure of melt flows and on the distribution of dissolved impurities in the liquid are examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ISPAn.II3..249J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ISPAn.II3..249J"><span><span class="hlt">Modelling</span> the Constraints of Spatial Environment in Fauna Movement Simulations: Comparison of a Boundaries <span class="hlt">Accurate</span> Function and a Cost Function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jolivet, L.; Cohen, M.; Ruas, A.</p> <p>2015-08-01</p> <p>Landscape influences fauna movement at different levels, from habitat selection to choices of movements' direction. Our goal is to provide a development frame in order to test simulation functions for animal's movement. We describe our approach for such simulations and we compare two <span class="hlt">types</span> of functions to calculate trajectories. To do so, we first <span class="hlt">modelled</span> the role of landscape elements to differentiate between elements that facilitate movements and the ones being hindrances. Different influences are identified depending on landscape elements and on animal species. Knowledge were gathered from ecologists, literature and observation datasets. Second, we analysed the description of animal movement recorded with GPS at fine scale, corresponding to high temporal frequency and good location accuracy. Analysing this <span class="hlt">type</span> of data provides information on the relation between landscape features and movements. We implemented an agent-based simulation approach to calculate potential trajectories constrained by the spatial environment and individual's behaviour. We tested two functions that consider space differently: one function takes into account the geometry and the <span class="hlt">types</span> of landscape elements and one cost function sums up the spatial surroundings of an individual. Results highlight the fact that the cost function exaggerates the distances travelled by an individual and simplifies movement patterns. The geometry <span class="hlt">accurate</span> function represents a good bottom-up approach for discovering interesting areas or obstacles for movements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26894674','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26894674"><span>Fitmunk: improving protein structures by <span class="hlt">accurate</span>, automatic <span class="hlt">modeling</span> of side-chain conformations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Porebski, Przemyslaw Jerzy; Cymborowski, Marcin; Pasenkiewicz-Gierula, Marta; Minor, Wladek</p> <p>2016-02-01</p> <p>Improvements in crystallographic hardware and software have allowed automated structure-solution pipelines to approach a near-`one-click' experience for the initial determination of macromolecular structures. However, in many cases the resulting initial <span class="hlt">model</span> requires a laborious, iterative process of refinement and validation. A new method has been developed for the automatic <span class="hlt">modeling</span> of side-chain conformations that takes advantage of rotamer-prediction methods in a crystallographic context. The algorithm, which is based on deterministic dead-end elimination (DEE) theory, uses new dense conformer libraries and a hybrid energy function derived from experimental data and prior information about rotamer frequencies to find the optimal conformation of each side chain. In contrast to existing methods, which incorporate the electron-density term into protein-<span class="hlt">modeling</span> frameworks, the proposed algorithm is designed to take advantage of the highly discriminatory nature of electron-density maps. This method has been implemented in the program Fitmunk, which uses extensive conformational sampling. This improves the accuracy of the <span class="hlt">modeling</span> and makes it a versatile tool for crystallographic <span class="hlt">model</span> building, refinement and validation. Fitmunk was extensively tested on over 115 new structures, as well as a subset of 1100 structures from the PDB. It is demonstrated that the ability of Fitmunk to <span class="hlt">model</span> more than 95% of side chains <span class="hlt">accurately</span> is beneficial for improving the quality of crystallographic protein <span class="hlt">models</span>, especially at medium and low resolutions. Fitmunk can be used for <span class="hlt">model</span> validation of existing structures and as a tool to assess whether side chains are <span class="hlt">modeled</span> optimally or could be better fitted into electron density. Fitmunk is available as a web service at http://kniahini.med.virginia.edu/fitmunk/server/ or at http://fitmunk.bitbucket.org/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008CQGra..25s8001C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008CQGra..25s8001C"><span>A note on tilted Bianchi <span class="hlt">type</span> VIh <span class="hlt">models</span>: the <span class="hlt">type</span> III bifurcation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coley, A. A.; Hervik, S.</p> <p>2008-10-01</p> <p>In this note we complete the analysis of Hervik, van den Hoogen, Lim and Coley (2007 Class. Quantum Grav. 24 3859) of the late-time behaviour of tilted perfect fluid Bianchi <span class="hlt">type</span> III <span class="hlt">models</span>. We consider <span class="hlt">models</span> with dust, and perfect fluids stiffer than dust, and eludicate the late-time behaviour by studying the centre manifold which dominates the behaviour of the <span class="hlt">model</span> at late times. In the dust case, this centre manifold is three-dimensional and can be considered a double bifurcation as the two parameters (h and γ) of the <span class="hlt">type</span> VIh <span class="hlt">model</span> are varied. We therefore complete the analysis of the late-time behaviour of tilted ever-expanding Bianchi <span class="hlt">models</span> of <span class="hlt">types</span> I VIII.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29415686','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29415686"><span>Prenatal and <span class="hlt">accurate</span> perinatal diagnosis of <span class="hlt">type</span> 2 H or ductular duplicate gallbladder.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maggi, Umberto; Farris, Giorgio; Carnevali, Alessandra; Borzani, Irene; Clerici, Paola; Agosti, Massimo; Rossi, Giorgio; Leva, Ernesto</p> <p>2018-02-07</p> <p>Double gallbladder is a rare biliary anomaly. Perinatal diagnosis of the disorder has been reported in only 6 cases, and in 5 of them the diagnosis was based on ultrasound imaging only. However, the ultrasound technique alone does not provide a sufficiently precise description of cystic ducts and biliary anatomy, an information that is crucial for a correct classification and for a possible future surgery. At 21 weeks of gestational age of an uneventful pregnancy in a 38 year old primipara mother, a routine ultrasound screening detected a biliary anomaly in the fetus suggestive of a double gallbladder. A neonatal abdominal ultrasonography performed on postnatal day 2 confirmed the diagnosis. On day 12 the newborn underwent a Magnetic Resonance Cholangiopancreatography (MRCP) that clearly characterized the anatomy of the anomaly: both gallbladders had their own cystic duct and both had a separate insertion in the main biliary duct. We report a case of early prenatal suspected duplicate gallbladder that was confirmed by a neonatal precise diagnosis of a <span class="hlt">Type</span> 2, H or ductular duplicate gallbladder, using for the first time 3D images of Magnetic resonance cholangiopancreatography in a newborn. An <span class="hlt">accurate</span> anatomical diagnosis is mandatory in patients undergoing a possible future cholecystectomy, to avoid surgical complications or reoperations. Therefore, in case of a perinatal suspicion of a double gallbladder, neonates should undergo a Magnetic resonance cholangiopancreatography. A review of the Literature about this variant is included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA344496','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA344496"><span>Simulation of Water Waves by <span class="hlt">Boussinesq</span> <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1998-03-01</p> <p>as nonlinearity. The other independent parameter is the ratio of water depth to wave length (fi = ho/L) or equivalently, the product of wavenumber...tw [l - (1 + 2a)//2] <f>\\A = 0 (2.118) Terms with products of 7?i,m and fatm (m = —1,1) indicate nonlinear interaction between the first order... product for u and ß is essential to the stability of uniform Stokes waves. From the analytical solutions, the values of u>" are always nega- tive. However</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24018780','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24018780"><span><span class="hlt">Accurate</span> and efficient <span class="hlt">modeling</span> of the detector response in small animal multi-head PET systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cecchetti, Matteo; Moehrs, Sascha; Belcari, Nicola; Del Guerra, Alberto</p> <p>2013-10-07</p> <p>In fully three-dimensional PET imaging, iterative image reconstruction techniques usually outperform analytical algorithms in terms of image quality provided that an appropriate system <span class="hlt">model</span> is used. In this study we concentrate on the calculation of an <span class="hlt">accurate</span> system <span class="hlt">model</span> for the YAP-(S)PET II small animal scanner, with the aim to obtain fully resolution- and contrast-recovered images at low levels of image roughness. For this purpose we calculate the system <span class="hlt">model</span> by decomposing it into a product of five matrices: (1) a detector response component obtained via Monte Carlo simulations, (2) a geometric component which describes the scanner geometry and which is calculated via a multi-ray method, (3) a detector normalization component derived from the acquisition of a planar source, (4) a photon attenuation component calculated from x-ray computed tomography data, and finally, (5) a positron range component is formally included. This system <span class="hlt">model</span> factorization allows the optimization of each component in terms of computation time, storage requirements and accuracy. The main contribution of this work is a new, efficient way to calculate the detector response component for rotating, planar detectors, that consists of a GEANT4 based simulation of a subset of lines of flight (LOFs) for a single detector head whereas the missing LOFs are obtained by using intrinsic detector symmetries. Additionally, we introduce and analyze a probability threshold for matrix elements of the detector component to optimize the trade-off between the matrix size in terms of non-zero elements and the resulting quality of the reconstructed images. In order to evaluate our proposed system <span class="hlt">model</span> we reconstructed various images of objects, acquired according to the NEMA NU 4-2008 standard, and we compared them to the images reconstructed with two other system <span class="hlt">models</span>: a <span class="hlt">model</span> that does not include any detector response component and a <span class="hlt">model</span> that approximates analytically the depth of interaction</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PMB....58.6713C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PMB....58.6713C"><span><span class="hlt">Accurate</span> and efficient <span class="hlt">modeling</span> of the detector response in small animal multi-head PET systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cecchetti, Matteo; Moehrs, Sascha; Belcari, Nicola; Del Guerra, Alberto</p> <p>2013-10-01</p> <p>In fully three-dimensional PET imaging, iterative image reconstruction techniques usually outperform analytical algorithms in terms of image quality provided that an appropriate system <span class="hlt">model</span> is used. In this study we concentrate on the calculation of an <span class="hlt">accurate</span> system <span class="hlt">model</span> for the YAP-(S)PET II small animal scanner, with the aim to obtain fully resolution- and contrast-recovered images at low levels of image roughness. For this purpose we calculate the system <span class="hlt">model</span> by decomposing it into a product of five matrices: (1) a detector response component obtained via Monte Carlo simulations, (2) a geometric component which describes the scanner geometry and which is calculated via a multi-ray method, (3) a detector normalization component derived from the acquisition of a planar source, (4) a photon attenuation component calculated from x-ray computed tomography data, and finally, (5) a positron range component is formally included. This system <span class="hlt">model</span> factorization allows the optimization of each component in terms of computation time, storage requirements and accuracy. The main contribution of this work is a new, efficient way to calculate the detector response component for rotating, planar detectors, that consists of a GEANT4 based simulation of a subset of lines of flight (LOFs) for a single detector head whereas the missing LOFs are obtained by using intrinsic detector symmetries. Additionally, we introduce and analyze a probability threshold for matrix elements of the detector component to optimize the trade-off between the matrix size in terms of non-zero elements and the resulting quality of the reconstructed images. In order to evaluate our proposed system <span class="hlt">model</span> we reconstructed various images of objects, acquired according to the NEMA NU 4-2008 standard, and we compared them to the images reconstructed with two other system <span class="hlt">models</span>: a <span class="hlt">model</span> that does not include any detector response component and a <span class="hlt">model</span> that approximates analytically the depth of interaction</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25362092','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25362092"><span>Mass spectrometry-based protein identification with <span class="hlt">accurate</span> statistical significance assignment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alves, Gelio; Yu, Yi-Kuo</p> <p>2015-03-01</p> <p>Assigning statistical significance <span class="hlt">accurately</span> has become increasingly important as metadata of many <span class="hlt">types</span>, often assembled in hierarchies, are constructed and combined for further biological analyses. Statistical inaccuracy of metadata at any level may propagate to downstream analyses, undermining the validity of scientific conclusions thus drawn. From the perspective of mass spectrometry-based proteomics, even though <span class="hlt">accurate</span> statistics for peptide identification can now be achieved, <span class="hlt">accurate</span> protein level statistics remain challenging. We have constructed a protein ID method that combines peptide evidences of a candidate protein based on a rigorous formula derived earlier; in this formula the database P-value of every peptide is weighted, prior to the final combination, according to the number of proteins it maps to. We have also shown that this protein ID method provides <span class="hlt">accurate</span> protein level E-value, eliminating the need of using empirical post-processing methods for <span class="hlt">type</span>-I error control. Using a known protein mixture, we find that this protein ID method, when combined with the Sorić formula, yields <span class="hlt">accurate</span> values for the proportion of false discoveries. In terms of retrieval efficacy, the results from our method are comparable with other methods tested. The source code, implemented in C++ on a linux system, is available for download at ftp://ftp.ncbi.nlm.nih.gov/pub/qmbp/qmbp_ms/RAId/RAId_Linux_64Bit. Published by Oxford University Press 2014. This work is written by US Government employees and is in the public domain in the US.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29289142','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29289142"><span><span class="hlt">Accurate</span> and balanced anisotropic Gaussian <span class="hlt">type</span> orbital basis sets for atoms in strong magnetic fields.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Wuming; Trickey, S B</p> <p>2017-12-28</p> <p>In high magnetic field calculations, anisotropic Gaussian <span class="hlt">type</span> orbital (AGTO) basis functions are capable of reconciling the competing demands of the spherically symmetric Coulombic interaction and cylindrical magnetic (B field) confinement. However, the best available a priori procedure for composing highly <span class="hlt">accurate</span> AGTO sets for atoms in a strong B field [W. Zhu et al., Phys. Rev. A 90, 022504 (2014)] yields very large basis sets. Their size is problematical for use in any calculation with unfavorable computational cost scaling. Here we provide an alternative constructive procedure. It is based upon analysis of the underlying physics of atoms in B fields that allow identification of several principles for the construction of AGTO basis sets. Aided by numerical optimization and parameter fitting, followed by fine tuning of fitting parameters, we devise formulae for generating <span class="hlt">accurate</span> AGTO basis sets in an arbitrary B field. For the hydrogen iso-electronic sequence, a set depends on B field strength, nuclear charge, and orbital quantum numbers. For multi-electron systems, the basis set formulae also include adjustment to account for orbital occupations. Tests of the new basis sets for atoms H through C (1 ≤ Z ≤ 6) and ions Li + , Be + , and B + , in a wide B field range (0 ≤ B ≤ 2000 a.u.), show an accuracy better than a few μhartree for single-electron systems and a few hundredths to a few mHs for multi-electron atoms. The relative errors are similar for different atoms and ions in a large B field range, from a few to a couple of tens of millionths, thereby confirming rather uniform accuracy across the nuclear charge Z and B field strength values. Residual basis set errors are two to three orders of magnitude smaller than the electronic correlation energies in multi-electron atoms, a signal of the usefulness of the new AGTO basis sets in correlated wavefunction or density functional calculations for atomic and molecular systems in an external strong B</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JChPh.147x4108Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JChPh.147x4108Z"><span><span class="hlt">Accurate</span> and balanced anisotropic Gaussian <span class="hlt">type</span> orbital basis sets for atoms in strong magnetic fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Wuming; Trickey, S. B.</p> <p>2017-12-01</p> <p>In high magnetic field calculations, anisotropic Gaussian <span class="hlt">type</span> orbital (AGTO) basis functions are capable of reconciling the competing demands of the spherically symmetric Coulombic interaction and cylindrical magnetic (B field) confinement. However, the best available a priori procedure for composing highly <span class="hlt">accurate</span> AGTO sets for atoms in a strong B field [W. Zhu et al., Phys. Rev. A 90, 022504 (2014)] yields very large basis sets. Their size is problematical for use in any calculation with unfavorable computational cost scaling. Here we provide an alternative constructive procedure. It is based upon analysis of the underlying physics of atoms in B fields that allow identification of several principles for the construction of AGTO basis sets. Aided by numerical optimization and parameter fitting, followed by fine tuning of fitting parameters, we devise formulae for generating <span class="hlt">accurate</span> AGTO basis sets in an arbitrary B field. For the hydrogen iso-electronic sequence, a set depends on B field strength, nuclear charge, and orbital quantum numbers. For multi-electron systems, the basis set formulae also include adjustment to account for orbital occupations. Tests of the new basis sets for atoms H through C (1 ≤ Z ≤ 6) and ions Li+, Be+, and B+, in a wide B field range (0 ≤ B ≤ 2000 a.u.), show an accuracy better than a few μhartree for single-electron systems and a few hundredths to a few mHs for multi-electron atoms. The relative errors are similar for different atoms and ions in a large B field range, from a few to a couple of tens of millionths, thereby confirming rather uniform accuracy across the nuclear charge Z and B field strength values. Residual basis set errors are two to three orders of magnitude smaller than the electronic correlation energies in multi-electron atoms, a signal of the usefulness of the new AGTO basis sets in correlated wavefunction or density functional calculations for atomic and molecular systems in an external strong B field.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1352377','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1352377"><span>Multi-fidelity machine learning <span class="hlt">models</span> for <span class="hlt">accurate</span> bandgap predictions of solids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Pilania, Ghanshyam; Gubernatis, James E.; Lookman, Turab</p> <p></p> <p>Here, we present a multi-fidelity co-kriging statistical learning framework that combines variable-fidelity quantum mechanical calculations of bandgaps to generate a machine-learned <span class="hlt">model</span> that enables low-cost <span class="hlt">accurate</span> predictions of the bandgaps at the highest fidelity level. Additionally, the adopted Gaussian process regression formulation allows us to predict the underlying uncertainties as a measure of our confidence in the predictions. In using a set of 600 elpasolite compounds as an example dataset and using semi-local and hybrid exchange correlation functionals within density functional theory as two levels of fidelities, we demonstrate the excellent learning performance of the method against actual high fidelitymore » quantum mechanical calculations of the bandgaps. The presented statistical learning method is not restricted to bandgaps or electronic structure methods and extends the utility of high throughput property predictions in a significant way.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1352377-multi-fidelity-machine-learning-models-accurate-bandgap-predictions-solids','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1352377-multi-fidelity-machine-learning-models-accurate-bandgap-predictions-solids"><span>Multi-fidelity machine learning <span class="hlt">models</span> for <span class="hlt">accurate</span> bandgap predictions of solids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Pilania, Ghanshyam; Gubernatis, James E.; Lookman, Turab</p> <p>2016-12-28</p> <p>Here, we present a multi-fidelity co-kriging statistical learning framework that combines variable-fidelity quantum mechanical calculations of bandgaps to generate a machine-learned <span class="hlt">model</span> that enables low-cost <span class="hlt">accurate</span> predictions of the bandgaps at the highest fidelity level. Additionally, the adopted Gaussian process regression formulation allows us to predict the underlying uncertainties as a measure of our confidence in the predictions. In using a set of 600 elpasolite compounds as an example dataset and using semi-local and hybrid exchange correlation functionals within density functional theory as two levels of fidelities, we demonstrate the excellent learning performance of the method against actual high fidelitymore » quantum mechanical calculations of the bandgaps. The presented statistical learning method is not restricted to bandgaps or electronic structure methods and extends the utility of high throughput property predictions in a significant way.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AAS...21732401M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AAS...21732401M"><span>Hierarchical <span class="hlt">Models</span> for <span class="hlt">Type</span> Ia Supernova Light Curves in the Optical and Near Infrared</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mandel, Kaisey; Narayan, G.; Kirshner, R. P.</p> <p>2011-01-01</p> <p>I have constructed a comprehensive statistical <span class="hlt">model</span> for <span class="hlt">Type</span> Ia supernova optical and near infrared light curves. Since the near infrared light curves are excellent standard candles and are less sensitive to dust extinction and reddening, the combination of near infrared and optical data better constrains the host galaxy extinction and improves the precision of distance predictions to SN Ia. A hierarchical probabilistic <span class="hlt">model</span> coherently accounts for multiple random and uncertain effects, including photometric error, intrinsic supernova light curve variations and correlations across phase and wavelength, dust extinction and reddening, peculiar velocity dispersion and distances. An improved BayeSN MCMC code is implemented for computing probabilistic inferences for individual supernovae and the SN Ia and host galaxy dust populations. I use this hierarchical <span class="hlt">model</span> to analyze nearby <span class="hlt">Type</span> Ia supernovae with optical and near infared data from the PAIRITEL, CfA3, and CSP samples and the literature. Using cross-validation to test the robustness of the <span class="hlt">model</span> predictions, I find that the rms Hubble diagram scatter of predicted distance moduli is 0.11 mag for SN with optical and near infrared data versus 0.15 mag for SN with only optical data. Accounting for the dispersion expected from random peculiar velocities, the rms intrinsic prediction error is 0.08-0.10 mag for SN with both optical and near infrared light curves. I discuss results for the inferred intrinsic correlation structures of the optical-NIR SN Ia light curves and the host galaxy dust distribution captured by the hierarchical <span class="hlt">model</span>. The continued observation and analysis of <span class="hlt">Type</span> Ia SN in the optical and near infrared is important for improving their utility as precise and <span class="hlt">accurate</span> cosmological distance indicators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27393413','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27393413"><span>Combined inverse-forward artificial neural networks for fast and <span class="hlt">accurate</span> estimation of the diffusion coefficients of cartilage based on multi-physics <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arbabi, Vahid; Pouran, Behdad; Weinans, Harrie; Zadpoor, Amir A</p> <p>2016-09-06</p> <p>Analytical and numerical methods have been used to extract essential engineering parameters such as elastic modulus, Poisson׳s ratio, permeability and diffusion coefficient from experimental data in various <span class="hlt">types</span> of biological tissues. The major limitation associated with analytical techniques is that they are often only applicable to problems with simplified assumptions. Numerical multi-physics methods, on the other hand, enable minimizing the simplified assumptions but require substantial computational expertise, which is not always available. In this paper, we propose a novel approach that combines inverse and forward artificial neural networks (ANNs) which enables fast and <span class="hlt">accurate</span> estimation of the diffusion coefficient of cartilage without any need for computational <span class="hlt">modeling</span>. In this approach, an inverse ANN is trained using our multi-zone biphasic-solute finite-bath computational <span class="hlt">model</span> of diffusion in cartilage to estimate the diffusion coefficient of the various zones of cartilage given the concentration-time curves. Robust estimation of the diffusion coefficients, however, requires introducing certain levels of stochastic variations during the training process. Determining the required level of stochastic variation is performed by coupling the inverse ANN with a forward ANN that receives the diffusion coefficient as input and returns the concentration-time curve as output. Combined together, forward-inverse ANNs enable computationally inexperienced users to obtain <span class="hlt">accurate</span> and fast estimation of the diffusion coefficients of cartilage zones. The diffusion coefficients estimated using the proposed approach are compared with those determined using direct scanning of the parameter space as the optimization approach. It has been shown that both approaches yield comparable results. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PMB....62.8376P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PMB....62.8376P"><span>A machine learning method for fast and <span class="hlt">accurate</span> characterization of depth-of-interaction gamma cameras</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pedemonte, Stefano; Pierce, Larry; Van Leemput, Koen</p> <p>2017-11-01</p> <p>Measuring the depth-of-interaction (DOI) of gamma photons enables increasing the resolution of emission imaging systems. Several design variants of DOI-sensitive detectors have been recently introduced to improve the performance of scanners for positron emission tomography (PET). However, the <span class="hlt">accurate</span> characterization of the response of DOI detectors, necessary to <span class="hlt">accurately</span> measure the DOI, remains an unsolved problem. Numerical simulations are, at the state of the art, imprecise, while measuring directly the characteristics of DOI detectors experimentally is hindered by the impossibility to impose the depth-of-interaction in an experimental set-up. In this article we introduce a machine learning approach for extracting <span class="hlt">accurate</span> forward <span class="hlt">models</span> of gamma imaging devices from simple pencil-beam measurements, using a nonlinear dimensionality reduction technique in combination with a finite mixture <span class="hlt">model</span>. The method is purely data-driven, not requiring simulations, and is applicable to a wide range of detector <span class="hlt">types</span>. The proposed method was evaluated both in a simulation study and with data acquired using a monolithic gamma camera designed for PET (the cMiCE detector), demonstrating the <span class="hlt">accurate</span> recovery of the DOI characteristics. The combination of the proposed calibration technique with maximum- a posteriori estimation of the coordinates of interaction provided a depth resolution of  ≈1.14 mm for the simulated PET detector and  ≈1.74 mm for the cMiCE detector. The software and experimental data are made available at http://occiput.mgh.harvard.edu/depthembedding/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP41A0594G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP41A0594G"><span>Filtering Raw Terrestrial Laser Scanning Data for Efficient and <span class="hlt">Accurate</span> Use in Geomorphologic <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gleason, M. J.; Pitlick, J.; Buttenfield, B. P.</p> <p>2011-12-01</p> <p>Terrestrial laser scanning (TLS) represents a new and particularly effective remote sensing technique for investigating geomorphologic processes. Unfortunately, TLS data are commonly characterized by extremely large volume, heterogeneous point distribution, and erroneous measurements, raising challenges for applied researchers. To facilitate efficient and <span class="hlt">accurate</span> use of TLS in geomorphology, and to improve accessibility for TLS processing in commercial software environments, we are developing a filtering method for raw TLS data to: eliminate data redundancy; produce a more uniformly spaced dataset; remove erroneous measurements; and maintain the ability of the TLS dataset to <span class="hlt">accurately</span> <span class="hlt">model</span> terrain. Our method conducts local aggregation of raw TLS data using a 3-D search algorithm based on the geometrical expression of expected random errors in the data. This approach accounts for the estimated accuracy and precision limitations of the instruments and procedures used in data collection, thereby allowing for identification and removal of potential erroneous measurements prior to data aggregation. Initial tests of the proposed technique on a sample TLS point cloud required a modest processing time of approximately 100 minutes to reduce dataset volume over 90 percent (from 12,380,074 to 1,145,705 points). Preliminary analysis of the filtered point cloud revealed substantial improvement in homogeneity of point distribution and minimal degradation of derived terrain <span class="hlt">models</span>. We will test the method on two independent TLS datasets collected in consecutive years along a non-vegetated reach of the North Fork Toutle River in Washington. We will evaluate the tool using various quantitative, qualitative, and statistical methods. The crux of this evaluation will include a bootstrapping analysis to test the ability of the filtered datasets to <span class="hlt">model</span> the terrain at roughly the same accuracy as the raw datasets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27088264','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27088264"><span>Lung ultrasound <span class="hlt">accurately</span> detects pneumothorax in a preterm newborn lamb <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Blank, Douglas A; Hooper, Stuart B; Binder-Heschl, Corinna; Kluckow, Martin; Gill, Andrew W; LaRosa, Domenic A; Inocencio, Ishmael M; Moxham, Alison; Rodgers, Karyn; Zahra, Valerie A; Davis, Peter G; Polglase, Graeme R</p> <p>2016-06-01</p> <p>Pneumothorax is a common emergency affecting extremely preterm. In adult studies, lung ultrasound has performed better than chest x-ray in the diagnosis of pneumothorax. The purpose of this study was to determine the efficacy of lung ultrasound (LUS) examination to detect pneumothorax using a preterm animal <span class="hlt">model</span>. This was a prospective, observational study using newborn Border-Leicester lambs at gestational age = 126 days (equivalent to gestational age = 26 weeks in humans) receiving mechanical ventilation from birth to 2 h of life. At the conclusion of the experiment, LUS was performed, the lambs were then euthanised and a post-mortem exam was immediately performed. We used previously published ultrasound techniques to identify pneumothorax. Test characteristics of LUS to detect pneumothorax were calculated, using the post-mortem exam as the 'gold standard' test. Nine lambs (18 lungs) were examined. Four lambs had a unilateral pneumothorax, all of which were identified by LUS with no false positives. This was the first study to use post-mortem findings to test the efficacy of LUS to detect pneumothorax in a newborn animal <span class="hlt">model</span>. Lung ultrasound <span class="hlt">accurately</span> detected pneumothorax, verified by post-mortem exam, in premature, newborn lambs. © 2016 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22521523-impact-accurate-extinction-measurements-ray-spectral-models','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22521523-impact-accurate-extinction-measurements-ray-spectral-models"><span>THE IMPACT OF <span class="hlt">ACCURATE</span> EXTINCTION MEASUREMENTS FOR X-RAY SPECTRAL <span class="hlt">MODELS</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Smith, Randall K.; Valencic, Lynne A.; Corrales, Lia, E-mail: lynne.a.valencic@nasa.gov</p> <p></p> <p>Interstellar extinction includes both absorption and scattering of photons from interstellar gas and dust grains, and it has the effect of altering a source's spectrum and its total observed intensity. However, while multiple absorption <span class="hlt">models</span> exist, there are no useful scattering <span class="hlt">models</span> in standard X-ray spectrum fitting tools, such as XSPEC. Nonetheless, X-ray halos, created by scattering from dust grains, are detected around even moderately absorbed sources, and the impact on an observed source spectrum can be significant, if modest, compared to direct absorption. By convolving the scattering cross section with dust <span class="hlt">models</span>, we have created a spectral <span class="hlt">model</span> asmore » a function of energy, <span class="hlt">type</span> of dust, and extraction region that can be used with <span class="hlt">models</span> of direct absorption. This will ensure that the extinction <span class="hlt">model</span> is consistent and enable direct connections to be made between a source's X-ray spectral fits and its UV/optical extinction.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/970155','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/970155"><span><span class="hlt">Modeling</span> Techniques Used to Analyze Safety of Payloads for Generic Missile <span class="hlt">Type</span> Weapons Systems During an Indirect Lightning Strike</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Perkins, M P; Ong, M M; Crull, E W</p> <p>2009-07-21</p> <p>During lightning strikes buildings and other structures can act as imperfect Faraday Cages, enabling electromagnetic fields to be developed inside the facilities. Some equipment stored inside these facilities may unfortunately act as antenna systems. It is important to have techniques developed to analyze how much voltage, current, or energy dissipation may be developed over valuable components. In this discussion we will demonstrate the <span class="hlt">modeling</span> techniques used to <span class="hlt">accurately</span> analyze a generic missile <span class="hlt">type</span> weapons system as it goes through different stages of assembly. As work is performed on weapons systems detonator cables can become exposed. These cables will form differentmore » monopole and loop <span class="hlt">type</span> antenna systems that must be analyzed to determine the voltages developed over the detonator regions. Due to the low frequencies of lightning pulses, a lumped element circuit <span class="hlt">model</span> can be developed to help analyze the different antenna configurations. We will show an example of how numerical <span class="hlt">modeling</span> can be used to develop the lumped element circuit <span class="hlt">models</span> used to calculate voltage, current, or energy dissipated over the detonator region of a generic missile <span class="hlt">type</span> weapons system.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22311052-equatorial-symmetry-boussinesq-convective-solutions-rotating-spherical-shell-allowing-rotation-inner-outer-spheres','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22311052-equatorial-symmetry-boussinesq-convective-solutions-rotating-spherical-shell-allowing-rotation-inner-outer-spheres"><span>Equatorial symmetry of <span class="hlt">Boussinesq</span> convective solutions in a rotating spherical shell allowing rotation of the inner and outer spheres</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kimura, Keiji; Takehiro, Shin-ichi; Yamada, Michio</p> <p>2014-08-15</p> <p>We investigate properties of convective solutions of the <span class="hlt">Boussinesq</span> thermal convection in a moderately rotating spherical shell allowing the respective rotation of the inner and outer spheres due to the viscous torque of the fluid. The ratio of the inner and outer radii of the spheres, the Prandtl number, and the Taylor number are fixed to 0.4, 1, and 500{sup 2}, respectively. The Rayleigh number is varied from 2.6 × 10{sup 4} to 3.4 × 10{sup 4}. In this parameter range, the behaviours of obtained asymptotic convective solutions are almost similar to those in the system whose inner and outermore » spheres are restricted to rotate with the same constant angular velocity, although the difference is found in the transition process to chaotic solutions. The convective solution changes from an equatorially symmetric quasi-periodic one to an equatorially symmetric chaotic one, and further to an equatorially asymmetric chaotic one, as the Rayleigh number is increased. This is in contrast to the transition in the system whose inner and outer spheres are assumed to rotate with the same constant angular velocity, where the convective solution changes from an equatorially symmetric quasi-periodic one, to an equatorially asymmetric quasi-periodic one, and to equatorially asymmetric chaotic one. The inner sphere rotates in the retrograde direction on average in the parameter range; however, it sometimes undergoes the prograde rotation when the convective solution becomes chaotic.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ISPAr.XL5a.211S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ISPAr.XL5a.211S"><span><span class="hlt">Accurate</span> 3d Textured <span class="hlt">Models</span> of Vessels for the Improvement of the Educational Tools of a Museum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Soile, S.; Adam, K.; Ioannidis, C.; Georgopoulos, A.</p> <p>2013-02-01</p> <p>Besides the demonstration of the findings, modern museums organize educational programs which aim to experience and knowledge sharing combined with entertainment rather than to pure learning. Toward that effort, 2D and 3D digital representations are gradually replacing the traditional recording of the findings through photos or drawings. The present paper refers to a project that aims to create 3D textured <span class="hlt">models</span> of two lekythoi that are exhibited in the National Archaeological Museum of Athens in Greece; on the surfaces of these lekythoi scenes of the adventures of Odysseus are depicted. The project is expected to support the production of an educational movie and some other relevant interactive educational programs for the museum. The creation of <span class="hlt">accurate</span> developments of the paintings and of <span class="hlt">accurate</span> 3D <span class="hlt">models</span> is the basis for the visualization of the adventures of the mythical hero. The data collection was made by using a structured light scanner consisting of two machine vision cameras that are used for the determination of geometry of the object, a high resolution camera for the recording of the texture, and a DLP projector. The creation of the final <span class="hlt">accurate</span> 3D textured <span class="hlt">model</span> is a complicated and tiring procedure which includes the collection of geometric data, the creation of the surface, the noise filtering, the merging of individual surfaces, the creation of a c-mesh, the creation of the UV map, the provision of the texture and, finally, the general processing of the 3D textured object. For a better result a combination of commercial and in-house software made for the automation of various steps of the procedure was used. The results derived from the above procedure were especially satisfactory in terms of accuracy and quality of the <span class="hlt">model</span>. However, the procedure was proved to be time consuming while the use of various software packages presumes the services of a specialist.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2247733S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2247733S"><span>Nonlinear convective pulsation <span class="hlt">models</span> of <span class="hlt">type</span> II Cepheids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smolec, Radoslaw</p> <p>2015-08-01</p> <p>We present a grid of nonlinear convective pulsation <span class="hlt">models</span> of <span class="hlt">type</span>-II Cepheids: BL Her stars, W Vir stars and RV Tau stars. The <span class="hlt">models</span> cover a wide range of masses, luminosities, effective temperatures and chemical compositions. The most interesting result is detection of deterministic chaos in the <span class="hlt">models</span>. Different routes to chaos are detected (period doubling, intermittent route) as well as variety of phenomena intrinsic to chaotic dynamics (periodic islands within chaotic bands, crisis bifurcation, <span class="hlt">type</span>-I and <span class="hlt">type</span>-III intermittency). Some of the phenomena (period doubling in BL Her and in RV Tau stars, irregular pulsation of RV Tau stars) are well known in the pulsation of <span class="hlt">type</span>-II Cepheids. Prospects of discovering the other are briefly discussed. Transition from BL Her <span class="hlt">type</span> pulsation through W Vir <span class="hlt">type</span> till RV Tau <span class="hlt">type</span> is analysed. In the most luminous <span class="hlt">models</span> a dynamical instability is detected, which indicates that pulsation driven mass loss is important process occurring in <span class="hlt">type</span>-II Cepheids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3591286','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3591286"><span>A Simple Iterative <span class="hlt">Model</span> <span class="hlt">Accurately</span> Captures Complex Trapline Formation by Bumblebees Across Spatial Scales and Flower Arrangements</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Reynolds, Andrew M.; Lihoreau, Mathieu; Chittka, Lars</p> <p>2013-01-01</p> <p>Pollinating bees develop foraging circuits (traplines) to visit multiple flowers in a manner that minimizes overall travel distance, a task analogous to the travelling salesman problem. We report on an in-depth exploration of an iterative improvement heuristic <span class="hlt">model</span> of bumblebee traplining previously found to <span class="hlt">accurately</span> replicate the establishment of stable routes by bees between flowers distributed over several hectares. The critical test for a <span class="hlt">model</span> is its predictive power for empirical data for which the <span class="hlt">model</span> has not been specifically developed, and here the <span class="hlt">model</span> is shown to be consistent with observations from different research groups made at several spatial scales and using multiple configurations of flowers. We refine the <span class="hlt">model</span> to account for the spatial search strategy of bees exploring their environment, and test several previously unexplored predictions. We find that the <span class="hlt">model</span> predicts <span class="hlt">accurately</span> 1) the increasing propensity of bees to optimize their foraging routes with increasing spatial scale; 2) that bees cannot establish stable optimal traplines for all spatial configurations of rewarding flowers; 3) the observed trade-off between travel distance and prioritization of high-reward sites (with a slight modification of the <span class="hlt">model</span>); 4) the temporal pattern with which bees acquire approximate solutions to travelling salesman-like problems over several dozen foraging bouts; 5) the instability of visitation schedules in some spatial configurations of flowers; 6) the observation that in some flower arrays, bees' visitation schedules are highly individually different; 7) the searching behaviour that leads to efficient location of flowers and routes between them. Our <span class="hlt">model</span> constitutes a robust theoretical platform to generate novel hypotheses and refine our understanding about how small-brained insects develop a representation of space and use it to navigate in complex and dynamic environments. PMID:23505353</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JChPh.133o4112R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JChPh.133o4112R"><span>Hindered rotor <span class="hlt">models</span> with variable kinetic functions for <span class="hlt">accurate</span> thermodynamic and kinetic predictions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reinisch, Guillaume; Leyssale, Jean-Marc; Vignoles, Gérard L.</p> <p>2010-10-01</p> <p>We present an extension of some popular hindered rotor (HR) <span class="hlt">models</span>, namely, the one-dimensional HR (1DHR) and the degenerated two-dimensional HR (d2DHR) <span class="hlt">models</span>, allowing for a simple and <span class="hlt">accurate</span> treatment of internal rotations. This extension, based on the use of a variable kinetic function in the Hamiltonian instead of a constant reduced moment of inertia, is extremely suitable in the case of rocking/wagging motions involved in dissociation or atom transfer reactions. The variable kinetic function is first introduced in the framework of a classical 1DHR <span class="hlt">model</span>. Then, an effective temperature and potential dependent constant is proposed in the cases of quantum 1DHR and classical d2DHR <span class="hlt">models</span>. These methods are finally applied to the atom transfer reaction SiCl3+BCl3→SiCl4+BCl2. We show, for this particular case, that a proper accounting of internal rotations greatly improves the accuracy of thermodynamic and kinetic predictions. Moreover, our results confirm (i) that using a suitably defined kinetic function appears to be very adapted to such problems; (ii) that the separability assumption of independent rotations seems justified; and (iii) that a quantum mechanical treatment is not a substantial improvement with respect to a classical one.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.474.5549S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.474.5549S"><span>KIC 6048106: an Algol-<span class="hlt">type</span> eclipsing system with long-term magnetic activity and hybrid pulsations - I. Binary <span class="hlt">modelling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samadi Ghadim, A.; Lampens, P.; Jassur, M.</p> <p>2018-03-01</p> <p>The A-F-<span class="hlt">type</span> stars and pulsators (δ Scuti-γ Dor) are in a critical regime where they experience a transition from radiative to convective transport of energy in their envelopes. Such stars can pulsate in both gravity and acoustic modes. Hence, the knowledge of their fundamental parameters along with their observed pulsation characteristics can help in improving the stellar <span class="hlt">models</span>. When residing in a binary system, these pulsators provide more <span class="hlt">accurate</span> and less <span class="hlt">model</span>-dependent stellar parameters than in the case of their single counterparts. We present a light-curve <span class="hlt">model</span> for the eclipsing system KIC 6048106 based on the Kepler photometry and the code PHOEBE. We aim to obtain <span class="hlt">accurate</span> physical parameters and tough constraints for the stellar <span class="hlt">modelling</span> of this intermediate-mass hybrid pulsator. We performed a separate <span class="hlt">modelling</span> of three light-curve segments which show a distinct behaviour due to a difference in activity. We also analysed the Kepler Eclipse Time Variations (ETVs). KIC 6048106 is an Algol-<span class="hlt">type</span> binary with F5-K5 components, a near-circular orbit and a 1.56-d period undergoing variations of the order of Δ P/P˜eq 3.60× 10^{-7} in 287 ± 7 d. The primary component is a main-sequence star with M1 = 1.55 ± 0.11 M⊙, R1 = 1.57 ± 0.12 R⊙. The secondary is a much cooler subgiant with M2 = 0.33 ± 0.07 M⊙, R2 = 1.77 ± 0.16 R⊙. Many small near-polar spots are active on its surface. The second quadrature phase shows a brightness modulation on a time-scale 290 ± 7 d, in good agreement with the ETV modulation. This study reveals a stable binary configuration along with clear evidence of a long-term activity of the secondary star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22253805-parallel-kinetic-monte-carlo-simulation-framework-incorporating-accurate-models-adsorbate-lateral-interactions','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22253805-parallel-kinetic-monte-carlo-simulation-framework-incorporating-accurate-models-adsorbate-lateral-interactions"><span>Parallel kinetic Monte Carlo simulation framework incorporating <span class="hlt">accurate</span> <span class="hlt">models</span> of adsorbate lateral interactions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Nielsen, Jens; D’Avezac, Mayeul; Hetherington, James</p> <p>2013-12-14</p> <p>Ab initio kinetic Monte Carlo (KMC) simulations have been successfully applied for over two decades to elucidate the underlying physico-chemical phenomena on the surfaces of heterogeneous catalysts. These simulations necessitate detailed knowledge of the kinetics of elementary reactions constituting the reaction mechanism, and the energetics of the species participating in the chemistry. The information about the energetics is encoded in the formation energies of gas and surface-bound species, and the lateral interactions between adsorbates on the catalytic surface, which can be <span class="hlt">modeled</span> at different levels of detail. The majority of previous works accounted for only pairwise-additive first nearest-neighbor interactions. Moremore » recently, cluster-expansion Hamiltonians incorporating long-range interactions and many-body terms have been used for detailed estimations of catalytic rate [C. Wu, D. J. Schmidt, C. Wolverton, and W. F. Schneider, J. Catal. 286, 88 (2012)]. In view of the increasing interest in <span class="hlt">accurate</span> predictions of catalytic performance, there is a need for general-purpose KMC approaches incorporating detailed cluster expansion <span class="hlt">models</span> for the adlayer energetics. We have addressed this need by building on the previously introduced graph-theoretical KMC framework, and we have developed Zacros, a FORTRAN2003 KMC package for simulating catalytic chemistries. To tackle the high computational cost in the presence of long-range interactions we introduce parallelization with OpenMP. We further benchmark our framework by simulating a KMC analogue of the NO oxidation system established by Schneider and co-workers [J. Catal. 286, 88 (2012)]. We show that taking into account only first nearest-neighbor interactions may lead to large errors in the prediction of the catalytic rate, whereas for <span class="hlt">accurate</span> estimates thereof, one needs to include long-range terms in the cluster expansion.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4950802H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4950802H"><span><span class="hlt">Accurate</span> Treatment of Collisions and Water-Delivery in <span class="hlt">Models</span> of Terrestrial Planet Formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haghighipour, Nader; Maindl, Thomas; Schaefer, Christoph</p> <p>2017-10-01</p> <p>It is widely accepted that collisions among solid bodies, ignited by their interactions with planetary embryos is the key process in the formation of terrestrial planets and transport of volatiles and chemical compounds to their accretion zones. Unfortunately, due to computational complexities, these collisions are often treated in a rudimentary way. Impacts are considered to be perfectly inelastic and volatiles are considered to be fully transferred from one object to the other. This perfect-merging assumption has profound effects on the mass and composition of final planetary bodies as it grossly overestimates the masses of these objects and the amounts of volatiles and chemical elements transferred to them. It also entirely neglects collisional-loss of volatiles (e.g., water) and draws an unrealistic connection between these properties and the chemical structure of the protoplanetary disk (i.e., the location of their original carriers). We have developed a new and comprehensive methodology to simulate growth of embryos to planetary bodies where we use a combination of SPH and N-body codes to <span class="hlt">accurately</span> <span class="hlt">model</span> collisions as well as the transport/transfer of chemical compounds. Our methodology accounts for the loss of volatiles (e.g., ice sublimation) during the orbital evolution of their careers and <span class="hlt">accurately</span> tracks their transfer from one body to another. Results of our simulations show that traditional N-body <span class="hlt">modeling</span> of terrestrial planet formation overestimates the amount of the mass and water contents of the final planets by over 60% implying that not only the amount of water they suggest is far from being realistic, small planets such as Mars can also form in these simulations when collisions are treated properly. We will present details of our methodology and discuss its implications for terrestrial planet formation and water delivery to Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H31G1584S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H31G1584S"><span>The feasibility of using a universal Random Forest <span class="hlt">model</span> to map tree height across different locations and vegetation <span class="hlt">types</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Y.; Guo, Q.; Jin, S.; Gao, S.; Hu, T.; Liu, J.; Xue, B. L.</p> <p>2017-12-01</p> <p>Tree height is an important forest structure parameter for understanding forest ecosystem and improving the accuracy of global carbon stock quantification. Light detection and ranging (LiDAR) can provide <span class="hlt">accurate</span> tree height measurements, but its use in large-scale tree height mapping is limited by the spatial availability. Random Forest (RF) has been one of the most commonly used algorithms for mapping large-scale tree height through the fusion of LiDAR and other remotely sensed datasets. However, how the variances in vegetation <span class="hlt">types</span>, geolocations and spatial scales of different study sites influence the RF results is still a question that needs to be addressed. In this study, we selected 16 study sites across four vegetation <span class="hlt">types</span> in United States (U.S.) fully covered by airborne LiDAR data, and the area of each site was 100 km2. The LiDAR-derived canopy height <span class="hlt">models</span> (CHMs) were used as the ground truth to train the RF algorithm to predict canopy height from other remotely sensed variables, such as Landsat TM imagery, terrain information and climate surfaces. To address the abovementioned question, 22 <span class="hlt">models</span> were run under different combinations of vegetation <span class="hlt">types</span>, geolocations and spatial scales. The results show that the RF <span class="hlt">model</span> trained at one specific location or vegetation <span class="hlt">type</span> cannot be used to predict tree height in other locations or vegetation <span class="hlt">types</span>. However, by training the RF <span class="hlt">model</span> using samples from all locations and vegetation <span class="hlt">types</span>, a universal <span class="hlt">model</span> can be achieved for predicting canopy height across different locations and vegetation <span class="hlt">types</span>. Moreover, the number of training samples and the targeted spatial resolution of the canopy height product have noticeable influence on the RF prediction accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27977188','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27977188"><span>Exchange-Hole Dipole Dispersion <span class="hlt">Model</span> for <span class="hlt">Accurate</span> Energy Ranking in Molecular Crystal Structure Prediction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Whittleton, Sarah R; Otero-de-la-Roza, A; Johnson, Erin R</p> <p>2017-02-14</p> <p><span class="hlt">Accurate</span> energy ranking is a key facet to the problem of first-principles crystal-structure prediction (CSP) of molecular crystals. This work presents a systematic assessment of B86bPBE-XDM, a semilocal density functional combined with the exchange-hole dipole moment (XDM) dispersion <span class="hlt">model</span>, for energy ranking using 14 compounds from the first five CSP blind tests. Specifically, the set of crystals studied comprises 11 rigid, planar compounds and 3 co-crystals. The experimental structure was correctly identified as the lowest in lattice energy for 12 of the 14 total crystals. One of the exceptions is 4-hydroxythiophene-2-carbonitrile, for which the experimental structure was correctly identified once a quasi-harmonic estimate of the vibrational free-energy contribution was included, evidencing the occasional importance of thermal corrections for <span class="hlt">accurate</span> energy ranking. The other exception is an organic salt, where charge-transfer error (also called delocalization error) is expected to cause the base density functional to be unreliable. Provided the choice of base density functional is appropriate and an estimate of temperature effects is used, XDM-corrected density-functional theory is highly reliable for the energetic ranking of competing crystal structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21975539','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21975539"><span>Combined DFT and BS study on the exchange coupling of dinuclear sandwich-<span class="hlt">type</span> POM: comparison of different functionals and reliability of structure <span class="hlt">modeling</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yin, Bing; Xue, GangLin; Li, JianLi; Bai, Lu; Huang, YuanHe; Wen, ZhenYi; Jiang, ZhenYi</p> <p>2012-05-01</p> <p>The exchange coupling of a group of three dinuclear sandwich-<span class="hlt">type</span> polyoxomolybdates [MM'(AsMo7O27)2](12-) with MM' = CrCr, FeFe, FeCr are theoretically predicted from combined DFT and broken-symmetry (BS) approach. Eight different XC functionals are utilized to calculate the exchange-coupling constant J from both the full crystalline structures and <span class="hlt">model</span> structures of smaller size. The comparison between theoretical values and <span class="hlt">accurate</span> experimental results supports the applicability of DFT-BS method in this new <span class="hlt">type</span> of sandwich-<span class="hlt">type</span> dinuclear polyoxomolybdates. However, a careful choice of functionals is necessary to achieve the desired accuracy. The encouraging results obtained from calculations on <span class="hlt">model</span> structures highlight the great potential of application of structure <span class="hlt">modeling</span> in theoretical study of POM. Structural <span class="hlt">modeling</span> may not only reduce the computational cost of large POM species but also be able to take into account the external field effect arising from solvent molecules in solution or counterions in crystal.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911635G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911635G"><span>Early-time solution of the horizontal unconfined aquifer in the build-up phase</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gravanis, Elias; Akylas, Evangelos</p> <p>2017-04-01</p> <p>The <span class="hlt">Boussinesq</span> equation is a dynamical equation for the free surface of saturated subsurface flows over an impervious bed. <span class="hlt">Boussinesq</span> equation is non-linear. The non-linearity comes from the reduction of the dimensionality of the problem: The flow is assumed to be vertically homogeneous, therefore the flow rate through a cross section of the flow is proportional to the free surface height times the hydraulic gradient, which is assumed to be equal to the slope of the free surface (Dupuit approximation). In general, 'vertically' means normally on the bed; combining the Dupuit approximation with the continuity equation leads to the <span class="hlt">Boussinesq</span> equation. There are very few transient exact solutions. Self- similar solutions have been constructed in the past by various authors. A power series <span class="hlt">type</span> of solution was derived for a self-similar <span class="hlt">Boussinesq</span> equation by Barenblatt in 1990. That <span class="hlt">type</span> of solution has generated a certain amount of literature. For the unconfined flow case for zero recharge rate <span class="hlt">Boussinesq</span> derived for the horizontal aquifer an exact solution assuming separation of variables. This is actually an exact asymptotic solution of the horizontal aquifer recession phase for late times. The kinematic wave is an interesting solution obtained by dropping the non-linear term in the <span class="hlt">Boussinesq</span> equation. Although it is an approximate solution, and holds well only for small values of the Henderson and Wooding λ parameter (that is, for steep slopes, high conductivity or small recharge rate), it becomes less and less approximate for smaller values of the parameter, that is, it is asymptotically exact with respect to that parameter. In the present work we consider the case of the unconfined subsurface flow over horizontal bed in the build-up phase under constant recharge rate. This is a case with an infinite Henderson and Wooding parameter, that is, it is the limiting case where the non-linear term is present in the <span class="hlt">Boussinesq</span> while the linear spatial derivative term</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol6/pdf/CFR-2010-title46-vol6-sec160-064-2.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol6/pdf/CFR-2010-title46-vol6-sec160-064-2.pdf"><span>46 CFR 160.064-2 - <span class="hlt">Types</span> and <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 46 Shipping 6 2010-10-01 2010-10-01 false <span class="hlt">Types</span> and <span class="hlt">models</span>. 160.064-2 Section 160.064-2 Shipping...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Marine Buoyant Devices § 160.064-2 <span class="hlt">Types</span> and <span class="hlt">models</span>. (a) <span class="hlt">Types</span>. Water safety buoyant devices covered by this subpart shall be of two general <span class="hlt">types</span>, viz, those intended...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H13G1469J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H13G1469J"><span>On the use of a physically-based baseflow timescale in land surface <span class="hlt">models</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jost, A.; Schneider, A. C.; Oudin, L.; Ducharne, A.</p> <p>2017-12-01</p> <p>Groundwater discharge is an important component of streamflow and estimating its spatio-temporal variation in response to changes in recharge is of great value to water resource planning, and essential for <span class="hlt">modelling</span> <span class="hlt">accurate</span> large scale water balance in land surface <span class="hlt">models</span> (LSMs). First-order representation of groundwater as a single linear storage element is frequently used in LSMs for the sake of simplicity, but requires a suitable parametrization of the aquifer hydraulic behaviour in the form of the baseflow characteristic timescale (τ). Such a <span class="hlt">modelling</span> approach can be hampered by the lack of available calibration data at global scale. Hydraulic groundwater theory provides an analytical framework to relate the baseflow characteristics to catchment descriptors. In this study, we use the long-time solution of the linearized <span class="hlt">Boussinesq</span> equation to estimate τ at global scale, as a function of groundwater flow length and aquifer hydraulic diffusivity. Our goal is to evaluate the use of this spatially variable and physically-based τ in the ORCHIDEE surface <span class="hlt">model</span> in terms of simulated river discharges across large catchments. Aquifer transmissivity and drainable porosity stem from GLHYMPS high-resolution datasets whereas flow length is derived from an estimation of drainage density, using the GRIN global river network. ORCHIDEE is run in offline mode and its results are compared to a reference simulation using an almost spatially constant topographic-dependent τ. We discuss the limits of our approach in terms of both the relevance and accuracy of global estimates of aquifer hydraulic properties and the extent to which the underlying assumptions in the analytical method are valid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1396096','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1396096"><span>Inverse and Predictive <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Syracuse, Ellen Marie</p> <p></p> <p>The LANL Seismo-Acoustic team has a strong capability in developing data-driven <span class="hlt">models</span> that <span class="hlt">accurately</span> predict a variety of observations. These <span class="hlt">models</span> range from the simple – one-dimensional <span class="hlt">models</span> that are constrained by a single dataset and can be used for quick and efficient predictions – to the complex – multidimensional <span class="hlt">models</span> that are constrained by several <span class="hlt">types</span> of data and result in more <span class="hlt">accurate</span> predictions. Team members typically build <span class="hlt">models</span> of geophysical characteristics of Earth and source distributions at scales of 1 to 1000s of km, the techniques used are applicable for other <span class="hlt">types</span> of physical characteristics at an evenmore » greater range of scales. The following cases provide a snapshot of some of the <span class="hlt">modeling</span> work done by the Seismo- Acoustic team at LANL.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28298126','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28298126"><span>Magnetic gaps in organic tri-radicals: From a simple <span class="hlt">model</span> to <span class="hlt">accurate</span> estimates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barone, Vincenzo; Cacelli, Ivo; Ferretti, Alessandro; Prampolini, Giacomo</p> <p>2017-03-14</p> <p>The calculation of the energy gap between the magnetic states of organic poly-radicals still represents a challenging playground for quantum chemistry, and high-level techniques are required to obtain <span class="hlt">accurate</span> estimates. On these grounds, the aim of the present study is twofold. From the one side, it shows that, thanks to recent algorithmic and technical improvements, we are able to compute reliable quantum mechanical results for the systems of current fundamental and technological interest. From the other side, proper parameterization of a simple Hubbard Hamiltonian allows for a sound rationalization of magnetic gaps in terms of basic physical effects, unraveling the role played by electron delocalization, Coulomb repulsion, and effective exchange in tuning the magnetic character of the ground state. As case studies, we have chosen three prototypical organic tri-radicals, namely, 1,3,5-trimethylenebenzene, 1,3,5-tridehydrobenzene, and 1,2,3-tridehydrobenzene, which differ either for geometric or electronic structure. After discussing the differences among the three species and their consequences on the magnetic properties in terms of the simple <span class="hlt">model</span> mentioned above, <span class="hlt">accurate</span> and reliable values for the energy gap between the lowest quartet and doublet states are computed by means of the so-called difference dedicated configuration interaction (DDCI) technique, and the final results are discussed and compared to both available experimental and computational estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApPhL.111v3110C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApPhL.111v3110C"><span>Rigorous numerical <span class="hlt">modeling</span> of scattering-<span class="hlt">type</span> scanning near-field optical microscopy and spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Xinzhong; Lo, Chiu Fan Bowen; Zheng, William; Hu, Hai; Dai, Qing; Liu, Mengkun</p> <p>2017-11-01</p> <p>Over the last decade, scattering-<span class="hlt">type</span> scanning near-field optical microscopy and spectroscopy have been widely used in nano-photonics and material research due to their fine spatial resolution and broad spectral range. A number of simplified analytical <span class="hlt">models</span> have been proposed to quantitatively understand the tip-scattered near-field signal. However, a rigorous interpretation of the experimental results is still lacking at this stage. Numerical <span class="hlt">modelings</span>, on the other hand, are mostly done by simulating the local electric field slightly above the sample surface, which only qualitatively represents the near-field signal rendered by the tip-sample interaction. In this work, we performed a more comprehensive numerical simulation which is based on realistic experimental parameters and signal extraction procedures. By directly comparing to the experiments as well as other simulation efforts, our methods offer a more <span class="hlt">accurate</span> quantitative description of the near-field signal, paving the way for future studies of complex systems at the nanoscale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15455936','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15455936"><span>Anatomically <span class="hlt">accurate</span> individual face <span class="hlt">modeling</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Yu; Prakash, Edmond C; Sung, Eric</p> <p>2003-01-01</p> <p>This paper presents a new 3D face <span class="hlt">model</span> of a specific person constructed from the anatomical perspective. By exploiting the laser range data, a 3D facial mesh precisely representing the skin geometry is reconstructed. Based on the geometric facial mesh, we develop a deformable multi-layer skin <span class="hlt">model</span>. It takes into account the nonlinear stress-strain relationship and dynamically simulates the non-homogenous behavior of the real skin. The face <span class="hlt">model</span> also incorporates a set of anatomically-motivated facial muscle actuators and underlying skull structure. Lagrangian mechanics governs the facial motion dynamics, dictating the dynamic deformation of facial skin in response to the muscle contraction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.115l1102B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.115l1102B"><span>Fast and <span class="hlt">Accurate</span> Prediction of Numerical Relativity Waveforms from Binary Black Hole Coalescences Using Surrogate <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blackman, Jonathan; Field, Scott E.; Galley, Chad R.; Szilágyi, Béla; Scheel, Mark A.; Tiglio, Manuel; Hemberger, Daniel A.</p> <p>2015-09-01</p> <p>Simulating a binary black hole coalescence by solving Einstein's equations is computationally expensive, requiring days to months of supercomputing time. Using reduced order <span class="hlt">modeling</span> techniques, we construct an <span class="hlt">accurate</span> surrogate <span class="hlt">model</span>, which is evaluated in a millisecond to a second, for numerical relativity (NR) waveforms from nonspinning binary black hole coalescences with mass ratios in [1, 10] and durations corresponding to about 15 orbits before merger. We assess the <span class="hlt">model</span>'s uncertainty and show that our <span class="hlt">modeling</span> strategy predicts NR waveforms not used for the surrogate's training with errors nearly as small as the numerical error of the NR code. Our <span class="hlt">model</span> includes all spherical-harmonic -2Yℓm waveform modes resolved by the NR code up to ℓ=8 . We compare our surrogate <span class="hlt">model</span> to effective one body waveforms from 50 M⊙ to 300 M⊙ for advanced LIGO detectors and find that the surrogate is always more faithful (by at least an order of magnitude in most cases).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26430979','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26430979"><span>Fast and <span class="hlt">Accurate</span> Prediction of Numerical Relativity Waveforms from Binary Black Hole Coalescences Using Surrogate <span class="hlt">Models</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Blackman, Jonathan; Field, Scott E; Galley, Chad R; Szilágyi, Béla; Scheel, Mark A; Tiglio, Manuel; Hemberger, Daniel A</p> <p>2015-09-18</p> <p>Simulating a binary black hole coalescence by solving Einstein's equations is computationally expensive, requiring days to months of supercomputing time. Using reduced order <span class="hlt">modeling</span> techniques, we construct an <span class="hlt">accurate</span> surrogate <span class="hlt">model</span>, which is evaluated in a millisecond to a second, for numerical relativity (NR) waveforms from nonspinning binary black hole coalescences with mass ratios in [1, 10] and durations corresponding to about 15 orbits before merger. We assess the <span class="hlt">model</span>'s uncertainty and show that our <span class="hlt">modeling</span> strategy predicts NR waveforms not used for the surrogate's training with errors nearly as small as the numerical error of the NR code. Our <span class="hlt">model</span> includes all spherical-harmonic _{-2}Y_{ℓm} waveform modes resolved by the NR code up to ℓ=8. We compare our surrogate <span class="hlt">model</span> to effective one body waveforms from 50M_{⊙} to 300M_{⊙} for advanced LIGO detectors and find that the surrogate is always more faithful (by at least an order of magnitude in most cases).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ASPC..445..171S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ASPC..445..171S"><span>Interferometric Constraints on Surface Brightness Asymmetries in Long-Period Variable Stars: A Threat to <span class="hlt">Accurate</span> Gaia Parallaxes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sacuto, S.; Jorissen, A.; Cruzalèbes, P.; Pasquato, E.; Chiavassa, A.; Spang, A.; Rabbia, Y.; Chesneau, O.</p> <p>2011-09-01</p> <p>A monitoring of surface brightness asymmetries in evolved giants and supergiants is necessary to estimate the threat that they represent to <span class="hlt">accurate</span> Gaia parallaxes. Closure-phase measurements obtained with AMBER/VISA in a 3-telescope configuration are fitted by a simple <span class="hlt">model</span> to constrain the photocenter displacement. The results for the C-<span class="hlt">type</span> star TX Psc show a large deviation of the photocenter displacement that could bias the Gaia parallax.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1429672-utilizing-adjoint-based-error-estimates-surrogate-models-accurately-predict-probabilities-events','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1429672-utilizing-adjoint-based-error-estimates-surrogate-models-accurately-predict-probabilities-events"><span>Utilizing Adjoint-Based Error Estimates for Surrogate <span class="hlt">Models</span> to <span class="hlt">Accurately</span> Predict Probabilities of Events</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Butler, Troy; Wildey, Timothy</p> <p>2018-01-01</p> <p>In thist study, we develop a procedure to utilize error estimates for samples of a surrogate <span class="hlt">model</span> to compute robust upper and lower bounds on estimates of probabilities of events. We show that these error estimates can also be used in an adaptive algorithm to simultaneously reduce the computational cost and increase the accuracy in estimating probabilities of events using computationally expensive high-fidelity <span class="hlt">models</span>. Specifically, we introduce the notion of reliability of a sample of a surrogate <span class="hlt">model</span>, and we prove that utilizing the surrogate <span class="hlt">model</span> for the reliable samples and the high-fidelity <span class="hlt">model</span> for the unreliable samples gives preciselymore » the same estimate of the probability of the output event as would be obtained by evaluation of the original <span class="hlt">model</span> for each sample. The adaptive algorithm uses the additional evaluations of the high-fidelity <span class="hlt">model</span> for the unreliable samples to locally improve the surrogate <span class="hlt">model</span> near the limit state, which significantly reduces the number of high-fidelity <span class="hlt">model</span> evaluations as the limit state is resolved. Numerical results based on a recently developed adjoint-based approach for estimating the error in samples of a surrogate are provided to demonstrate (1) the robustness of the bounds on the probability of an event, and (2) that the adaptive enhancement algorithm provides a more <span class="hlt">accurate</span> estimate of the probability of the QoI event than standard response surface approximation methods at a lower computational cost.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1429672-utilizing-adjoint-based-error-estimates-surrogate-models-accurately-predict-probabilities-events','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1429672-utilizing-adjoint-based-error-estimates-surrogate-models-accurately-predict-probabilities-events"><span>Utilizing Adjoint-Based Error Estimates for Surrogate <span class="hlt">Models</span> to <span class="hlt">Accurately</span> Predict Probabilities of Events</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Butler, Troy; Wildey, Timothy</p> <p></p> <p>In thist study, we develop a procedure to utilize error estimates for samples of a surrogate <span class="hlt">model</span> to compute robust upper and lower bounds on estimates of probabilities of events. We show that these error estimates can also be used in an adaptive algorithm to simultaneously reduce the computational cost and increase the accuracy in estimating probabilities of events using computationally expensive high-fidelity <span class="hlt">models</span>. Specifically, we introduce the notion of reliability of a sample of a surrogate <span class="hlt">model</span>, and we prove that utilizing the surrogate <span class="hlt">model</span> for the reliable samples and the high-fidelity <span class="hlt">model</span> for the unreliable samples gives preciselymore » the same estimate of the probability of the output event as would be obtained by evaluation of the original <span class="hlt">model</span> for each sample. The adaptive algorithm uses the additional evaluations of the high-fidelity <span class="hlt">model</span> for the unreliable samples to locally improve the surrogate <span class="hlt">model</span> near the limit state, which significantly reduces the number of high-fidelity <span class="hlt">model</span> evaluations as the limit state is resolved. Numerical results based on a recently developed adjoint-based approach for estimating the error in samples of a surrogate are provided to demonstrate (1) the robustness of the bounds on the probability of an event, and (2) that the adaptive enhancement algorithm provides a more <span class="hlt">accurate</span> estimate of the probability of the QoI event than standard response surface approximation methods at a lower computational cost.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23781409','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23781409"><span>Prediction of morbidity and mortality in patients with <span class="hlt">type</span> 2 diabetes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wells, Brian J; Roth, Rachel; Nowacki, Amy S; Arrigain, Susana; Yu, Changhong; Rosenkrans, Wayne A; Kattan, Michael W</p> <p>2013-01-01</p> <p>Introduction. The objective of this study was to create a tool that <span class="hlt">accurately</span> predicts the risk of morbidity and mortality in patients with <span class="hlt">type</span> 2 diabetes according to an oral hypoglycemic agent. Materials and Methods. The <span class="hlt">model</span> was based on a cohort of 33,067 patients with <span class="hlt">type</span> 2 diabetes who were prescribed a single oral hypoglycemic agent at the Cleveland Clinic between 1998 and 2006. Competing risk regression <span class="hlt">models</span> were created for coronary heart disease (CHD), heart failure, and stroke, while a Cox regression <span class="hlt">model</span> was created for mortality. Propensity scores were used to account for possible treatment bias. A prediction tool was created and internally validated using tenfold cross-validation. The results were compared to a Framingham <span class="hlt">model</span> and a <span class="hlt">model</span> based on the United Kingdom Prospective Diabetes Study (UKPDS) for CHD and stroke, respectively. Results and Discussion. Median follow-up for the mortality outcome was 769 days. The numbers of patients experiencing events were as follows: CHD (3062), heart failure (1408), stroke (1451), and mortality (3661). The prediction tools demonstrated the following concordance indices (c-statistics) for the specific outcomes: CHD (0.730), heart failure (0.753), stroke (0.688), and mortality (0.719). The prediction tool was superior to the Framingham <span class="hlt">model</span> at predicting CHD and was at least as <span class="hlt">accurate</span> as the UKPDS <span class="hlt">model</span> at predicting stroke. Conclusions. We created an <span class="hlt">accurate</span> tool for predicting the risk of stroke, coronary heart disease, heart failure, and death in patients with <span class="hlt">type</span> 2 diabetes. The calculator is available online at http://rcalc.ccf.org under the heading "<span class="hlt">Type</span> 2 Diabetes" and entitled, "Predicting 5-Year Morbidity and Mortality." This may be a valuable tool to aid the clinician's choice of an oral hypoglycemic, to better inform patients, and to motivate dialogue between physician and patient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9637E..20S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9637E..20S"><span>Processing of airborne laser scanning data to generate <span class="hlt">accurate</span> DTM for floodplain wetland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Szporak-Wasilewska, Sylwia; Mirosław-Świątek, Dorota; Grygoruk, Mateusz; Michałowski, Robert; Kardel, Ignacy</p> <p>2015-10-01</p> <p>Structure of the floodplain, especially its topography and vegetation, influences the overland flow and dynamics of floods which are key factors shaping ecosystems in surface water-fed wetlands. Therefore elaboration of the digital terrain <span class="hlt">model</span> (DTM) of a high spatial accuracy is crucial in hydrodynamic flow <span class="hlt">modelling</span> in river valleys. In this study the research was conducted in the unique Central European complex of fens and marshes - the Lower Biebrza river valley. The area is represented mainly by peat ecosystems which according to EU Water Framework Directive (WFD) are called "water-dependent ecosystems". Development of <span class="hlt">accurate</span> DTM in these areas which are overgrown by dense wetland vegetation consisting of alder forest, willow shrubs, reed, sedges and grass is very difficult, therefore to represent terrain in high accuracy the airborne laser scanning data (ALS) with scanning density of 4 points/m2 was used and the correction of the "vegetation effect" on DTM was executed. This correction was performed utilizing remotely sensed images, topographical survey using the Real Time Kinematic positioning and vegetation height measurements. In order to classify different <span class="hlt">types</span> of vegetation within research area the object based image analysis (OBIA) was used. OBIA allowed partitioning remotely sensed imagery into meaningful image-objects, and assessing their characteristics through spatial and spectral scale. The final maps of vegetation patches that include attributes of vegetation height and vegetation spectral properties, utilized both the laser scanning data and the vegetation indices developed on the basis of airborne and satellite imagery. This data was used in process of segmentation, attribution and classification. Several different vegetation indices were tested to distinguish different <span class="hlt">types</span> of vegetation in wetland area. The OBIA classification allowed correction of the "vegetation effect" on DTM. The final digital terrain <span class="hlt">model</span> was compared and examined</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AAS...21534305M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AAS...21534305M"><span><span class="hlt">Type</span> Ia Supernova Light Curve Inference: Hierarchical <span class="hlt">Models</span> for Nearby SN Ia in the Optical and Near Infrared</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mandel, Kaisey; Kirshner, R. P.; Narayan, G.; Wood-Vasey, W. M.; Friedman, A. S.; Hicken, M.</p> <p>2010-01-01</p> <p>I have constructed a comprehensive statistical <span class="hlt">model</span> for <span class="hlt">Type</span> Ia supernova light curves spanning optical through near infrared data simultaneously. The near infrared light curves are found to be excellent standard candles (sigma(MH) = 0.11 +/- 0.03 mag) that are less vulnerable to systematic error from dust extinction, a major confounding factor for cosmological studies. A hierarchical statistical framework incorporates coherently multiple sources of randomness and uncertainty, including photometric error, intrinsic supernova light curve variations and correlations, dust extinction and reddening, peculiar velocity dispersion and distances, for probabilistic inference with <span class="hlt">Type</span> Ia SN light curves. Inferences are drawn from the full probability density over individual supernovae and the SN Ia and dust populations, conditioned on a dataset of SN Ia light curves and redshifts. To compute probabilistic inferences with hierarchical <span class="hlt">models</span>, I have developed BayeSN, a Markov Chain Monte Carlo algorithm based on Gibbs sampling. This code explores and samples the global probability density of parameters describing individual supernovae and the population. I have applied this hierarchical <span class="hlt">model</span> to optical and near infrared data of over 100 nearby <span class="hlt">Type</span> Ia SN from PAIRITEL, the CfA3 sample, and the literature. Using this statistical <span class="hlt">model</span>, I find that SN with optical and NIR data have a smaller residual scatter in the Hubble diagram than SN with only optical data. The continued study of <span class="hlt">Type</span> Ia SN in the near infrared will be important for improving their utility as precise and <span class="hlt">accurate</span> cosmological distance indicators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050182919','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050182919"><span>Partially-Averaged Navier Stokes <span class="hlt">Model</span> for Turbulence: Implementation and Validation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Girimaji, Sharath S.; Abdol-Hamid, Khaled S.</p> <p>2005-01-01</p> <p>Partially-averaged Navier Stokes (PANS) is a suite of turbulence closure <span class="hlt">models</span> of various <span class="hlt">modeled</span>-to-resolved scale ratios ranging from Reynolds-averaged Navier Stokes (RANS) to Navier-Stokes (direct numerical simulations). The objective of PANS, like hybrid <span class="hlt">models</span>, is to resolve large scale structures at reasonable computational expense. The <span class="hlt">modeled</span>-to-resolved scale ratio or the level of physical resolution in PANS is quantified by two parameters: the unresolved-to-total ratios of kinetic energy (f(sub k)) and dissipation (f(sub epsilon)). The unresolved-scale stress is <span class="hlt">modeled</span> with the <span class="hlt">Boussinesq</span> approximation and <span class="hlt">modeled</span> transport equations are solved for the unresolved kinetic energy and dissipation. In this paper, we first present a brief discussion of the PANS philosophy followed by a description of the implementation procedure and finally perform preliminary evaluation in benchmark problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3138492','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3138492"><span><span class="hlt">Accurate</span> <span class="hlt">modelling</span> of single-particle cryo-EM images quantifies the benefits expected from using Zernike phase contrast</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hall, R. J.; Nogales, E.; Glaeser, R. M.</p> <p>2011-01-01</p> <p>The use of a Zernike-<span class="hlt">type</span> phase plate in biological cryo-electron microscopy allows the imaging, without using defocus, of what are predominantly phase objects. It is thought that such phase-plate implementations might result in higher quality images, free from the problems of CTF correction that occur when images must be recorded at extremely high values of defocus. In single-particle cryo-electron microscopy it is hoped that these improvements in image quality will facilitate work on structures that have proved difficult to study, either because of their relatively small size or because the structures are not completely homogeneous. There is still a need, however, to quantify how much improvement can be gained by using a phase plate for single-particle cryo-electron microscopy. We present a method for quantitatively <span class="hlt">modelling</span> the images recorded with 200 keV electrons, for single particles embedded in vitreous ice. We then investigate what difference the use of a phase-plate device could have on the processing of single-particle data. We confirm that using a phase plate results in single-particle datasets in which smaller molecules can be detected, particles can be more <span class="hlt">accurately</span> aligned and problems of heterogeneity can be more easily addressed. PMID:21463690</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDA19001S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDA19001S"><span>Capillary waves with surface viscosity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Li; Denner, Fabian; Morgan, Neal; van Wachem, Berend; Dini, Daniele</p> <p>2017-11-01</p> <p>Experiments over the last 50 years have suggested a correlation between the surface (shear) viscosity and the stability of a foam or emulsion. With recent techniques allowing more <span class="hlt">accurate</span> measurements of the elusive surface viscosity, we examine this link theoretically using small-amplitude capillary waves in the presence of the Marangoni effect and surface viscosity <span class="hlt">modelled</span> via the <span class="hlt">Boussinesq</span>-Scriven <span class="hlt">model</span>. The surface viscosity effect is found to contribute a damping effect on the amplitude of the capillary wave with subtle differences to the effect of the convective-diffusive Marangoni transport. The general wave dispersion is augmented to take into account the Marangoni and surface viscosity effects, and a first-order correction to the critical damping wavelength is derived. The authors acknowledge the financial support of the Shell University Technology Centre for fuels and lubricants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3405937','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3405937"><span>THE EFFECTS OF VIDEO <span class="hlt">MODELING</span> WITH VOICEOVER INSTRUCTION ON <span class="hlt">ACCURATE</span> IMPLEMENTATION OF DISCRETE-TRIAL INSTRUCTION</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vladescu, Jason C; Carroll, Regina; Paden, Amber; Kodak, Tiffany M</p> <p>2012-01-01</p> <p>The present study replicates and extends previous research on the use of video <span class="hlt">modeling</span> (VM) with voiceover instruction to train staff to implement discrete-trial instruction (DTI). After staff trainees reached the mastery criterion when teaching an adult confederate with VM, they taught a child with a developmental disability using DTI. The results showed that the staff trainees' <span class="hlt">accurate</span> implementation of DTI remained high, and both child participants acquired new skills. These findings provide additional support that VM may be an effective method to train staff members to conduct DTI. PMID:22844149</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22844149','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22844149"><span>The effects of video <span class="hlt">modeling</span> with voiceover instruction on <span class="hlt">accurate</span> implementation of discrete-trial instruction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vladescu, Jason C; Carroll, Regina; Paden, Amber; Kodak, Tiffany M</p> <p>2012-01-01</p> <p>The present study replicates and extends previous research on the use of video <span class="hlt">modeling</span> (VM) with voiceover instruction to train staff to implement discrete-trial instruction (DTI). After staff trainees reached the mastery criterion when teaching an adult confederate with VM, they taught a child with a developmental disability using DTI. The results showed that the staff trainees' <span class="hlt">accurate</span> implementation of DTI remained high, and both child participants acquired new skills. These findings provide additional support that VM may be an effective method to train staff members to conduct DTI.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870011870','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870011870"><span>Boundary-layer computational <span class="hlt">model</span> for predicting the flow and heat transfer in sudden expansions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lewis, J. P.; Pletcher, R. H.</p> <p>1986-01-01</p> <p>Fully developed turbulent and laminar flows through symmetric planar and axisymmetric expansions with heat transfer were <span class="hlt">modeled</span> using a finite-difference discretization of the boundary-layer equations. By using the boundary-layer equations to <span class="hlt">model</span> separated flow in place of the Navier-Stokes equations, computational effort was reduced permitting turbulence <span class="hlt">modelling</span> studies to be economically carried out. For laminar flow, the reattachment length was well predicted for Reynolds numbers as low as 20 and the details of the trapped eddy were well predicted for Reynolds numbers above 200. For turbulent flows, the <span class="hlt">Boussinesq</span> assumption was used to express the Reynolds stresses in terms of a turbulent viscosity. Near-wall algebraic turbulence <span class="hlt">models</span> based on Prandtl's-mixing-length <span class="hlt">model</span> and the maximum Reynolds shear stress were compared.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050196615','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050196615"><span><span class="hlt">Accurate</span> Time-Dependent Traveling-Wave Tube <span class="hlt">Model</span> Developed for Computational Bit-Error-Rate Testing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kory, Carol L.</p> <p>2001-01-01</p> <p>The phenomenal growth of the satellite communications industry has created a large demand for traveling-wave tubes (TWT's) operating with unprecedented specifications requiring the design and production of many novel devices in record time. To achieve this, the TWT industry heavily relies on computational <span class="hlt">modeling</span>. However, the TWT industry's computational <span class="hlt">modeling</span> capabilities need to be improved because there are often discrepancies between measured TWT data and that predicted by conventional two-dimensional helical TWT interaction codes. This limits the analysis and design of novel devices or TWT's with parameters differing from what is conventionally manufactured. In addition, the inaccuracy of current computational tools limits achievable TWT performance because optimized designs require highly <span class="hlt">accurate</span> <span class="hlt">models</span>. To address these concerns, a fully three-dimensional, time-dependent, helical TWT interaction <span class="hlt">model</span> was developed using the electromagnetic particle-in-cell code MAFIA (Solution of MAxwell's equations by the Finite-Integration-Algorithm). The <span class="hlt">model</span> includes a short section of helical slow-wave circuit with excitation fed by radiofrequency input/output couplers, and an electron beam contained by periodic permanent magnet focusing. A cutaway view of several turns of the three-dimensional helical slow-wave circuit with input/output couplers is shown. This has been shown to be more <span class="hlt">accurate</span> than conventionally used two-dimensional <span class="hlt">models</span>. The growth of the communications industry has also imposed a demand for increased data rates for the transmission of large volumes of data. To achieve increased data rates, complex modulation and multiple access techniques are employed requiring minimum distortion of the signal as it is passed through the TWT. Thus, intersymbol interference (ISI) becomes a major consideration, as well as suspected causes such as reflections within the TWT. To experimentally investigate effects of the physical TWT on ISI would be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhRvD..97b3504G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhRvD..97b3504G"><span>Fast and <span class="hlt">accurate</span> computation of projected two-point functions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grasshorn Gebhardt, Henry S.; Jeong, Donghui</p> <p>2018-01-01</p> <p>We present the two-point function from the fast and <span class="hlt">accurate</span> spherical Bessel transformation (2-FAST) algorithm<fn id="fn1"><label>1</label>Our code is available at https://github.com/hsgg/twoFAST.</fn> for a fast and <span class="hlt">accurate</span> computation of integrals involving one or two spherical Bessel functions. These <span class="hlt">types</span> of integrals occur when projecting the galaxy power spectrum P (k ) onto the configuration space, ξℓν(r ), or spherical harmonic space, Cℓ(χ ,χ'). First, we employ the FFTLog transformation of the power spectrum to divide the calculation into P (k )-dependent coefficients and P (k )-independent integrations of basis functions multiplied by spherical Bessel functions. We find analytical expressions for the latter integrals in terms of special functions, for which recursion provides a fast and <span class="hlt">accurate</span> evaluation. The algorithm, therefore, circumvents direct integration of highly oscillating spherical Bessel functions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29187987','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29187987"><span>Using multiple data <span class="hlt">types</span> and integrated population <span class="hlt">models</span> to improve our knowledge of apex predator population dynamics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bled, Florent; Belant, Jerrold L; Van Daele, Lawrence J; Svoboda, Nathan; Gustine, David; Hilderbrand, Grant; Barnes, Victor G</p> <p>2017-11-01</p> <p>Current management of large carnivores is informed using a variety of parameters, methods, and metrics; however, these data are typically considered independently. Sharing information among data <span class="hlt">types</span> based on the underlying ecological, and recognizing observation biases, can improve estimation of individual and global parameters. We present a general integrated population <span class="hlt">model</span> (IPM), specifically designed for brown bears ( Ursus arctos ), using three common data <span class="hlt">types</span> for bear ( U . spp.) populations: repeated counts, capture-mark-recapture, and litter size. We considered factors affecting ecological and observation processes for these data. We assessed the practicality of this approach on a simulated population and compared estimates from our <span class="hlt">model</span> to values used for simulation and results from count data only. We then present a practical application of this general approach adapted to the constraints of a case study using historical data available for brown bears on Kodiak Island, Alaska, USA. The IPM provided more <span class="hlt">accurate</span> and precise estimates than <span class="hlt">models</span> accounting for repeated count data only, with credible intervals including the true population 94% and 5% of the time, respectively. For the Kodiak population, we estimated annual average litter size (within one year after birth) to vary between 0.45 [95% credible interval: 0.43; 0.55] and 1.59 [1.55; 1.82]. We detected a positive relationship between salmon availability and adult survival, with survival probabilities greater for females than males. Survival probabilities increased from cubs to yearlings to dependent young ≥2 years old and decreased with litter size. Linking multiple information sources based on ecological and observation mechanisms can provide more <span class="hlt">accurate</span> and precise estimates, to better inform management. IPMs can also reduce data collection efforts by sharing information among agencies and management units. Our approach responds to an increasing need in bear populations' management</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193699','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193699"><span>Using multiple data <span class="hlt">types</span> and integrated population <span class="hlt">models</span> to improve our knowledge of apex predator population dynamics</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bled, Florent; Belant, Jerrold L.; Van Daele, Lawrence J.; Svoboda, Nathan; Gustine, David D.; Hilderbrand, Grant V.; Barnes, Victor G.</p> <p>2017-01-01</p> <p>Current management of large carnivores is informed using a variety of parameters, methods, and metrics; however, these data are typically considered independently. Sharing information among data <span class="hlt">types</span> based on the underlying ecological, and recognizing observation biases, can improve estimation of individual and global parameters. We present a general integrated population <span class="hlt">model</span> (IPM), specifically designed for brown bears (Ursus arctos), using three common data <span class="hlt">types</span> for bear (U. spp.) populations: repeated counts, capture–mark–recapture, and litter size. We considered factors affecting ecological and observation processes for these data. We assessed the practicality of this approach on a simulated population and compared estimates from our <span class="hlt">model</span> to values used for simulation and results from count data only. We then present a practical application of this general approach adapted to the constraints of a case study using historical data available for brown bears on Kodiak Island, Alaska, USA. The IPM provided more <span class="hlt">accurate</span> and precise estimates than <span class="hlt">models</span> accounting for repeated count data only, with credible intervals including the true population 94% and 5% of the time, respectively. For the Kodiak population, we estimated annual average litter size (within one year after birth) to vary between 0.45 [95% credible interval: 0.43; 0.55] and 1.59 [1.55; 1.82]. We detected a positive relationship between salmon availability and adult survival, with survival probabilities greater for females than males. Survival probabilities increased from cubs to yearlings to dependent young ≥2 years old and decreased with litter size. Linking multiple information sources based on ecological and observation mechanisms can provide more <span class="hlt">accurate</span> and precise estimates, to better inform management. IPMs can also reduce data collection efforts by sharing information among agencies and management units. Our approach responds to an increasing need in bear populations’ management</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPA....7e6660K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPA....7e6660K"><span>An <span class="hlt">accurate</span> real-time <span class="hlt">model</span> of maglev planar motor based on compound Simpson numerical integration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kou, Baoquan; Xing, Feng; Zhang, Lu; Zhou, Yiheng; Liu, Jiaqi</p> <p>2017-05-01</p> <p>To realize the high-speed and precise control of the maglev planar motor, a more <span class="hlt">accurate</span> real-time electromagnetic <span class="hlt">model</span>, which considers the influence of the coil corners, is proposed in this paper. Three coordinate systems for the stator, mover and corner coil are established. The coil is divided into two segments, the straight coil segment and the corner coil segment, in order to obtain a complete electromagnetic <span class="hlt">model</span>. When only take the first harmonic of the flux density distribution of a Halbach magnet array into account, the integration method can be carried out towards the two segments according to Lorenz force law. The force and torque analysis formula of the straight coil segment can be derived directly from Newton-Leibniz formula, however, this is not applicable to the corner coil segment. Therefore, Compound Simpson numerical integration method is proposed in this paper to solve the corner segment. With the validation of simulation and experiment, the proposed <span class="hlt">model</span> has high accuracy and can realize practical application easily.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25823460','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25823460"><span><span class="hlt">Accurate</span> <span class="hlt">typing</span> of short tandem repeats from genome-wide sequencing data and its applications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fungtammasan, Arkarachai; Ananda, Guruprasad; Hile, Suzanne E; Su, Marcia Shu-Wei; Sun, Chen; Harris, Robert; Medvedev, Paul; Eckert, Kristin; Makova, Kateryna D</p> <p>2015-05-01</p> <p>Short tandem repeats (STRs) are implicated in dozens of human genetic diseases and contribute significantly to genome variation and instability. Yet profiling STRs from short-read sequencing data is challenging because of their high sequencing error rates. Here, we developed STR-FM, short tandem repeat profiling using flank-based mapping, a computational pipeline that can detect the full spectrum of STR alleles from short-read data, can adapt to emerging read-mapping algorithms, and can be applied to heterogeneous genetic samples (e.g., tumors, viruses, and genomes of organelles). We used STR-FM to study STR error rates and patterns in publicly available human and in-house generated ultradeep plasmid sequencing data sets. We discovered that STRs sequenced with a PCR-free protocol have up to ninefold fewer errors than those sequenced with a PCR-containing protocol. We constructed an error correction <span class="hlt">model</span> for genotyping STRs that can distinguish heterozygous alleles containing STRs with consecutive repeat numbers. Applying our <span class="hlt">model</span> and pipeline to Illumina sequencing data with 100-bp reads, we could confidently genotype several disease-related long trinucleotide STRs. Utilizing this pipeline, for the first time we determined the genome-wide STR germline mutation rate from a deeply sequenced human pedigree. Additionally, we built a tool that recommends minimal sequencing depth for <span class="hlt">accurate</span> STR genotyping, depending on repeat length and sequencing read length. The required read depth increases with STR length and is lower for a PCR-free protocol. This suite of tools addresses the pressing challenges surrounding STR genotyping, and thus is of wide interest to researchers investigating disease-related STRs and STR evolution. © 2015 Fungtammasan et al.; Published by Cold Spring Harbor Laboratory Press.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhDT........15E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhDT........15E"><span>Developments toward more <span class="hlt">accurate</span> molecular <span class="hlt">modeling</span> of liquids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Evans, Tom J.</p> <p>2000-12-01</p> <p>The general goal of this research has been to improve upon existing combined quantum mechanics/molecular mechanics (QM/MM) methodologies. Error weighting functions have been introduced into the perturbative Monte Carlo (PMC) method for use with QM/MM. The PMC approach, introduced earlier, provides a means to reduce the number of full self-consistent field (SCF) calculations in simulations using the QM/MM potential by evoking perturbation theory to calculate energy changes due to displacements of a MM molecule. This will allow the ab initio QM/MM approach to be applied to systems that require more advanced, computationally demanding treatments of the QM and/or MM regions. Efforts have also been made to improve the accuracy of the representation of the solvent molecules usually represented by MM force fields. Results from an investigation of the applicability of the embedded density functional theory (EDFT) for studying physical properties of solutions will be presented. In this approach, the solute wavefunction is solved self- consistently in the field of individually frozen electron-density solvent molecules. To test its accuracy, the potential curves for interactions between Li+, Cl- and H2O with a single frozen-density H 2O molecule in different orientations have been calculated. With the development of the more sophisticated effective fragment potential (EFP) representation of solvent molecules, a QM/EFP technique was created. This hybrid QM/EFP approach was used to investigate the solvation of Li + by small clusters of water, as a test case for larger ionic dusters. The EFP appears to provide an <span class="hlt">accurate</span> representation of the strong interactions that exist between Li+ and H2O. With the QM/EFP methodology comes an increased computational expense, resulting in an even greater need to rely on the PMC approach. However, while including the PMC into the hybrid QM/EFP technique, it was discovered that the previous implementation of the PMC was done incorrectly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT........19B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........19B"><span>Multi-Physics Computational Grains (MPCGs): Newly-Developed <span class="hlt">Accurate</span> and Efficient Numerical Methods for Micromechanical <span class="hlt">Modeling</span> of Multifunctional Materials and Composites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bishay, Peter L.</p> <p></p> <p>This study presents a new family of highly <span class="hlt">accurate</span> and efficient computational methods for <span class="hlt">modeling</span> the multi-physics of multifunctional materials and composites in the micro-scale named "Multi-Physics Computational Grains" (MPCGs). Each "mathematical grain" has a random polygonal/polyhedral geometrical shape that resembles the natural shapes of the material grains in the micro-scale where each grain is surrounded by an arbitrary number of neighboring grains. The physics that are incorporated in this study include: Linear Elasticity, Electrostatics, Magnetostatics, Piezoelectricity, Piezomagnetism and Ferroelectricity. However, the methods proposed here can be extended to include more physics (thermo-elasticity, pyroelectricity, electric conduction, heat conduction, etc.) in their formulation, different analysis <span class="hlt">types</span> (dynamics, fracture, fatigue, etc.), nonlinearities, different defect shapes, and some of the 2D methods can also be extended to 3D formulation. We present "Multi-Region Trefftz Collocation Grains" (MTCGs) as a simple and efficient method for direct and inverse problems, "Trefftz-Lekhnitskii Computational Gains" (TLCGs) for <span class="hlt">modeling</span> porous and composite smart materials, "Hybrid Displacement Computational Grains" (HDCGs) as a general method for <span class="hlt">modeling</span> multifunctional materials and composites, and finally "Radial-Basis-Functions Computational Grains" (RBFCGs) for <span class="hlt">modeling</span> functionally-graded materials, magneto-electro-elastic (MEE) materials and the switching phenomena in ferroelectric materials. The first three proposed methods are suitable for direct numerical simulation (DNS) of the micromechanics of smart composite/porous materials with non-symmetrical arrangement of voids/inclusions, and provide minimal effort in meshing and minimal time in computations, since each grain can represent the matrix of a composite and can include a pore or an inclusion. The last three methods provide stiffness matrix in their formulation and hence can be readily</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3673157','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3673157"><span>The importance of <span class="hlt">accurate</span> muscle <span class="hlt">modelling</span> for biomechanical analyses: a case study with a lizard skull</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gröning, Flora; Jones, Marc E. H.; Curtis, Neil; Herrel, Anthony; O'Higgins, Paul; Evans, Susan E.; Fagan, Michael J.</p> <p>2013-01-01</p> <p>Computer-based simulation techniques such as multi-body dynamics analysis are becoming increasingly popular in the field of skull mechanics. Multi-body <span class="hlt">models</span> can be used for studying the relationships between skull architecture, muscle morphology and feeding performance. However, to be confident in the <span class="hlt">modelling</span> results, <span class="hlt">models</span> need to be validated against experimental data, and the effects of uncertainties or inaccuracies in the chosen <span class="hlt">model</span> attributes need to be assessed with sensitivity analyses. Here, we compare the bite forces predicted by a multi-body <span class="hlt">model</span> of a lizard (Tupinambis merianae) with in vivo measurements, using anatomical data collected from the same specimen. This subject-specific <span class="hlt">model</span> predicts bite forces that are very close to the in vivo measurements and also shows a consistent increase in bite force as the bite position is moved posteriorly on the jaw. However, the <span class="hlt">model</span> is very sensitive to changes in muscle attributes such as fibre length, intrinsic muscle strength and force orientation, with bite force predictions varying considerably when these three variables are altered. We conclude that <span class="hlt">accurate</span> muscle measurements are crucial to building realistic multi-body <span class="hlt">models</span> and that subject-specific data should be used whenever possible. PMID:23614944</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28056090','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28056090"><span><span class="hlt">Accurate</span> De Novo Prediction of Protein Contact Map by Ultra-Deep Learning <span class="hlt">Model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Sheng; Sun, Siqi; Li, Zhen; Zhang, Renyu; Xu, Jinbo</p> <p>2017-01-01</p> <p>Protein contacts contain key information for the understanding of protein structure and function and thus, contact prediction from sequence is an important problem. Recently exciting progress has been made on this problem, but the predicted contacts for proteins without many sequence homologs is still of low quality and not very useful for de novo structure prediction. This paper presents a new deep learning method that predicts contacts by integrating both evolutionary coupling (EC) and sequence conservation information through an ultra-deep neural network formed by two deep residual neural networks. The first residual network conducts a series of 1-dimensional convolutional transformation of sequential features; the second residual network conducts a series of 2-dimensional convolutional transformation of pairwise information including output of the first residual network, EC information and pairwise potential. By using very deep residual networks, we can <span class="hlt">accurately</span> <span class="hlt">model</span> contact occurrence patterns and complex sequence-structure relationship and thus, obtain higher-quality contact prediction regardless of how many sequence homologs are available for proteins in question. Our method greatly outperforms existing methods and leads to much more <span class="hlt">accurate</span> contact-assisted folding. Tested on 105 CASP11 targets, 76 past CAMEO hard targets, and 398 membrane proteins, the average top L long-range prediction accuracy obtained by our method, one representative EC method CCMpred and the CASP11 winner MetaPSICOV is 0.47, 0.21 and 0.30, respectively; the average top L/10 long-range accuracy of our method, CCMpred and MetaPSICOV is 0.77, 0.47 and 0.59, respectively. Ab initio folding using our predicted contacts as restraints but without any force fields can yield correct folds (i.e., TMscore>0.6) for 203 of the 579 test proteins, while that using MetaPSICOV- and CCMpred-predicted contacts can do so for only 79 and 62 of them, respectively. Our contact-assisted <span class="hlt">models</span> also have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5249242','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5249242"><span><span class="hlt">Accurate</span> De Novo Prediction of Protein Contact Map by Ultra-Deep Learning <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Zhen; Zhang, Renyu</p> <p>2017-01-01</p> <p>Motivation Protein contacts contain key information for the understanding of protein structure and function and thus, contact prediction from sequence is an important problem. Recently exciting progress has been made on this problem, but the predicted contacts for proteins without many sequence homologs is still of low quality and not very useful for de novo structure prediction. Method This paper presents a new deep learning method that predicts contacts by integrating both evolutionary coupling (EC) and sequence conservation information through an ultra-deep neural network formed by two deep residual neural networks. The first residual network conducts a series of 1-dimensional convolutional transformation of sequential features; the second residual network conducts a series of 2-dimensional convolutional transformation of pairwise information including output of the first residual network, EC information and pairwise potential. By using very deep residual networks, we can <span class="hlt">accurately</span> <span class="hlt">model</span> contact occurrence patterns and complex sequence-structure relationship and thus, obtain higher-quality contact prediction regardless of how many sequence homologs are available for proteins in question. Results Our method greatly outperforms existing methods and leads to much more <span class="hlt">accurate</span> contact-assisted folding. Tested on 105 CASP11 targets, 76 past CAMEO hard targets, and 398 membrane proteins, the average top L long-range prediction accuracy obtained by our method, one representative EC method CCMpred and the CASP11 winner MetaPSICOV is 0.47, 0.21 and 0.30, respectively; the average top L/10 long-range accuracy of our method, CCMpred and MetaPSICOV is 0.77, 0.47 and 0.59, respectively. Ab initio folding using our predicted contacts as restraints but without any force fields can yield correct folds (i.e., TMscore>0.6) for 203 of the 579 test proteins, while that using MetaPSICOV- and CCMpred-predicted contacts can do so for only 79 and 62 of them, respectively. Our contact</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MS%26E..309a2069P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MS%26E..309a2069P"><span>De-embedding technique for <span class="hlt">accurate</span> <span class="hlt">modeling</span> of compact 3D MMIC CPW transmission lines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pohan, U. H.; KKyabaggu, P. B.; Sinulingga, E. P.</p> <p>2018-02-01</p> <p>Requirement for high-density and high-functionality microwave and millimeter-wave circuits have led to the innovative circuit architectures such as three-dimensional multilayer MMICs. The major advantage of the multilayer techniques is that one can employ passive and active components based on CPW technology. In this work, MMIC Coplanar Waveguide(CPW)components such as Transmission Line (TL) are <span class="hlt">modeled</span> in their 3D layouts. Main characteristics of CPWTL suffered from the probe pads’ parasitic and resonant frequency effects have been studied. By understanding the parasitic effects, then the novel de-embedding technique are developed <span class="hlt">accurately</span> in order to predict high frequency characteristics of the designed MMICs. The novel de-embedding technique has shown to be critical in reducing the probe pad parasitic significantly from the <span class="hlt">model</span>. As results, high frequency characteristics of the designed MMICs have been presented with minimumparasitic effects of the probe pads. The de-embedding process optimises the determination of main characteristics of Compact 3D MMIC CPW transmission lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28914982','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28914982"><span>Production of <span class="hlt">accurate</span> skeletal <span class="hlt">models</span> of domestic animals using three-dimensional scanning and printing technology.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Fangzheng; Liu, Chunying; Song, Xuexiong; Huan, Yanjun; Gao, Shansong; Jiang, Zhongling</p> <p>2018-01-01</p> <p>Access to adequate anatomical specimens can be an important aspect in learning the anatomy of domestic animals. In this study, the authors utilized a structured light scanner and fused deposition <span class="hlt">modeling</span> (FDM) printer to produce highly <span class="hlt">accurate</span> animal skeletal <span class="hlt">models</span>. First, various components of the bovine skeleton, including the femur, the fifth rib, and the sixth cervical (C6) vertebra were used to produce digital <span class="hlt">models</span>. These were then used to produce 1:1 scale physical <span class="hlt">models</span> with the FDM printer. The anatomical features of the digital <span class="hlt">models</span> and three-dimensional (3D) printed <span class="hlt">models</span> were then compared with those of the original skeletal specimens. The results of this study demonstrated that both digital and physical scale <span class="hlt">models</span> of animal skeletal components could be rapidly produced using 3D printing technology. In terms of accuracy between <span class="hlt">models</span> and original specimens, the standard deviations of the femur and the fifth rib measurements were 0.0351 and 0.0572, respectively. All of the features except the nutrient foramina on the original bone specimens could be identified in the digital and 3D printed <span class="hlt">models</span>. Moreover, the 3D printed <span class="hlt">models</span> could serve as a viable alternative to original bone specimens when used in anatomy education, as determined from student surveys. This study demonstrated an important example of reproducing bone <span class="hlt">models</span> to be used in anatomy education and veterinary clinical training. Anat Sci Educ 11: 73-80. © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5038777','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5038777"><span>Finite Element <span class="hlt">Modelling</span> of a Field-Sensed Magnetic Suspended System for <span class="hlt">Accurate</span> Proximity Measurement Based on a Sensor Fusion Algorithm with Unscented Kalman Filter</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chowdhury, Amor; Sarjaš, Andrej</p> <p>2016-01-01</p> <p>The presented paper describes <span class="hlt">accurate</span> distance measurement for a field-sensed magnetic suspension system. The proximity measurement is based on a Hall effect sensor. The proximity sensor is installed directly on the lower surface of the electro-magnet, which means that it is very sensitive to external magnetic influences and disturbances. External disturbances interfere with the information signal and reduce the usability and reliability of the proximity measurements and, consequently, the whole application operation. A sensor fusion algorithm is deployed for the aforementioned reasons. The sensor fusion algorithm is based on the Unscented Kalman Filter, where a nonlinear dynamic <span class="hlt">model</span> was derived with the Finite Element <span class="hlt">Modelling</span> approach. The advantage of such <span class="hlt">modelling</span> is a more <span class="hlt">accurate</span> dynamic <span class="hlt">model</span> parameter estimation, especially in the case when the real structure, materials and dimensions of the real-time application are known. The novelty of the paper is the design of a compact electro-magnetic actuator with a built-in low cost proximity sensor for <span class="hlt">accurate</span> proximity measurement of the magnetic object. The paper successively presents a <span class="hlt">modelling</span> procedure with the finite element method, design and parameter settings of a sensor fusion algorithm with Unscented Kalman Filter and, finally, the implementation procedure and results of real-time operation. PMID:27649197</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27649197','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27649197"><span>Finite Element <span class="hlt">Modelling</span> of a Field-Sensed Magnetic Suspended System for <span class="hlt">Accurate</span> Proximity Measurement Based on a Sensor Fusion Algorithm with Unscented Kalman Filter.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chowdhury, Amor; Sarjaš, Andrej</p> <p>2016-09-15</p> <p>The presented paper describes <span class="hlt">accurate</span> distance measurement for a field-sensed magnetic suspension system. The proximity measurement is based on a Hall effect sensor. The proximity sensor is installed directly on the lower surface of the electro-magnet, which means that it is very sensitive to external magnetic influences and disturbances. External disturbances interfere with the information signal and reduce the usability and reliability of the proximity measurements and, consequently, the whole application operation. A sensor fusion algorithm is deployed for the aforementioned reasons. The sensor fusion algorithm is based on the Unscented Kalman Filter, where a nonlinear dynamic <span class="hlt">model</span> was derived with the Finite Element <span class="hlt">Modelling</span> approach. The advantage of such <span class="hlt">modelling</span> is a more <span class="hlt">accurate</span> dynamic <span class="hlt">model</span> parameter estimation, especially in the case when the real structure, materials and dimensions of the real-time application are known. The novelty of the paper is the design of a compact electro-magnetic actuator with a built-in low cost proximity sensor for <span class="hlt">accurate</span> proximity measurement of the magnetic object. The paper successively presents a <span class="hlt">modelling</span> procedure with the finite element method, design and parameter settings of a sensor fusion algorithm with Unscented Kalman Filter and, finally, the implementation procedure and results of real-time operation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/289269','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/289269"><span>Time-dependent buoyant puff <span class="hlt">model</span> for explosive sources</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kansa, E.J.</p> <p>1997-01-01</p> <p>Several <span class="hlt">models</span> exist to predict the time dependent behavior of bouyant puffs that result from explosions. This paper presents a new <span class="hlt">model</span> that is derived from the strong conservative form of the conservation partial differential equations that are integrated over space to yield a coupled system of time dependent nonlinear ordinary differential equations. This <span class="hlt">model</span> permits the cloud to evolve from an intial spherical shape not an ellipsoidal shape. It ignores the <span class="hlt">Boussinesq</span> approximation, and treats the turbulence that is generated by the puff itself and the ambient atmospheric tubulence as separate mechanisms in determining the puff history. The puffmore » cloud rise history was found to depend no only on the mass and initial temperature of the explosion, but also upon the stability conditions of the ambient atmosphere. This <span class="hlt">model</span> was calibrated by comparison with the Roller Coaster experiments.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22402516-modeling-nonlinear-dynamics-autonomous-silva-young-type-chaotic-oscillators-flat-power-spectrum','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22402516-modeling-nonlinear-dynamics-autonomous-silva-young-type-chaotic-oscillators-flat-power-spectrum"><span>On the <span class="hlt">modeling</span> and nonlinear dynamics of autonomous Silva-Young <span class="hlt">type</span> chaotic oscillators with flat power spectrum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kengne, Jacques; Kenmogne, Fabien</p> <p>2014-12-15</p> <p>The nonlinear dynamics of fourth-order Silva-Young <span class="hlt">type</span> chaotic oscillators with flat power spectrum recently introduced by Tamaseviciute and collaborators is considered. In this <span class="hlt">type</span> of oscillators, a pair of semiconductor diodes in an anti-parallel connection acts as the nonlinear component necessary for generating chaotic oscillations. Based on the Shockley diode equation and an appropriate selection of the state variables, a smooth mathematical <span class="hlt">model</span> (involving hyperbolic sine and cosine functions) is derived for a better description of both the regular and chaotic dynamics of the system. The complex behavior of the oscillator is characterized in terms of its parameters by usingmore » time series, bifurcation diagrams, Lyapunov exponents' plots, Poincaré sections, and frequency spectra. It is shown that the onset of chaos is achieved via the classical period-doubling and symmetry restoring crisis scenarios. Some PSPICE simulations of the nonlinear dynamics of the oscillator are presented in order to confirm the ability of the proposed mathematical <span class="hlt">model</span> to <span class="hlt">accurately</span> describe/predict both the regular and chaotic behaviors of the oscillator.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002PhFl...14..492L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002PhFl...14..492L"><span><span class="hlt">Modeling</span> pinchoff and reconnection in a Hele-Shaw cell. I. The <span class="hlt">models</span> and their calibration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Hyeong-Gi; Lowengrub, J. S.; Goodman, J.</p> <p>2002-02-01</p> <p>This is the first paper in a two-part series in which we analyze two <span class="hlt">model</span> systems to study pinchoff and reconnection in binary fluid flow in a Hele-Shaw cell with arbitrary density and viscosity contrast between the components. The systems stem from a simplification of a general system of equations governing the motion of a binary fluid (NSCH <span class="hlt">model</span> [Lowengrub and Truskinovsky, Proc. R. Soc. London, Ser. A 454, 2617 (1998)]) to flow in a Hele-Shaw cell. The system takes into account the chemical diffusivity between different components of a fluid mixture and the reactive stresses induced by inhomogeneity. In one of the systems we consider (HSCH), the binary fluid may be compressible due to diffusion. In the other system (BHSCH), a <span class="hlt">Boussinesq</span> approximation is used and the fluid is incompressible. In this paper, we motivate, present and calibrate the HSCH/BHSCH equations so as to yield the classical sharp interface <span class="hlt">model</span> as a limiting case. We then analyze their equilibria, one dimensional evolution and linear stability. In the second paper [paper II, Phys. Fluids 14, 514 (2002)], we analyze the behavior of the <span class="hlt">models</span> in the fully nonlinear regime. In the BHSCH system, the equilibrium concentration profile is obtained using the classical Maxwell construction [Rowlinson and Widom, Molecular Theory of Capillarity (Clarendon, Oxford, 1979)] and does not depend on the orientation of the gravitational field. We find that the equilibria in the HSCH <span class="hlt">model</span> are somewhat surprising as the gravitational field actually affects the internal structure of an isolated interface by driving additional stratification of light and heavy fluids over that predicted in the <span class="hlt">Boussinesq</span> case. A comparison of the linear growth rates indicates that the HSCH system is slightly more diffusive than the BHSCH system. In both, linear convergence to the sharp interface growth rates is observed in a parameter controlling the interface thickness. In addition, we identify the effect that each of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170001023&hterms=1094&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231094','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170001023&hterms=1094&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231094"><span>Fast and <span class="hlt">Accurate</span> Hybrid Stream PCRTMSOLAR Radiative Transfer <span class="hlt">Model</span> for Reflected Solar Spectrum Simulation in the Cloudy Atmosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yang, Qiguang; Liu, Xu; Wu, Wan; Kizer, Susan; Baize, Rosemary R.</p> <p>2016-01-01</p> <p>A hybrid stream PCRTM-SOLAR <span class="hlt">model</span> has been proposed for fast and <span class="hlt">accurate</span> radiative transfer simulation. It calculates the reflected solar (RS) radiances with a fast coarse way and then, with the help of a pre-saved matrix, transforms the results to obtain the desired high <span class="hlt">accurate</span> RS spectrum. The methodology has been demonstrated with the hybrid stream discrete ordinate (HSDO) radiative transfer (RT) <span class="hlt">model</span>. The HSDO method calculates the monochromatic radiances using a 4-stream discrete ordinate method, where only a small number of monochromatic radiances are simulated with both 4-stream and a larger N-stream (N = 16) discrete ordinate RT algorithm. The accuracy of the obtained channel radiance is comparable to the result from N-stream moderate resolution atmospheric transmission version 5 (MODTRAN5). The root-mean-square errors are usually less than 5x10(exp -4) mW/sq cm/sr/cm. The computational speed is three to four-orders of magnitude faster than the medium speed correlated-k option MODTRAN5. This method is very efficient to simulate thousands of RS spectra under multi-layer clouds/aerosols and solar radiation conditions for climate change study and numerical weather prediction applications.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10563E..44R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10563E..44R"><span>SPEX: a highly <span class="hlt">accurate</span> spectropolarimeter for atmospheric aerosol characterization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rietjens, J. H. H.; Smit, J. M.; di Noia, A.; Hasekamp, O. P.; van Harten, G.; Snik, F.; Keller, C. U.</p> <p>2017-11-01</p> <p>Global characterization of atmospheric aerosol in terms of the microphysical properties of the particles is essential for understanding the role aerosols in Earth climate [1]. For more <span class="hlt">accurate</span> predictions of future climate the uncertainties of the net radiative forcing of aerosols in the Earth's atmosphere must be reduced [2]. Essential parameters that are needed as input in climate <span class="hlt">models</span> are not only the aerosol optical thickness (AOT), but also particle specific properties such as the aerosol mean size, the single scattering albedo (SSA) and the complex refractive index. The latter can be used to discriminate between absorbing and non-absorbing aerosol <span class="hlt">types</span>, and between natural and anthropogenic aerosol. Classification of aerosol <span class="hlt">types</span> is also very important for air-quality and health-related issues [3]. Remote sensing from an orbiting satellite platform is the only way to globally characterize atmospheric aerosol at a relevant timescale of 1 day [4]. One of the few methods that can be employed for measuring the microphysical properties of aerosols is to observe both radiance and degree of linear polarization of sunlight scattered in the Earth atmosphere under different viewing directions [5][6][7]. The requirement on the absolute accuracy of the degree of linear polarization PL is very stringent: the absolute error in PL must be smaller then 0.001+0.005.PL in order to retrieve aerosol parameters with sufficient accuracy to advance climate <span class="hlt">modelling</span> and to enable discrimination of aerosol <span class="hlt">types</span> based on their refractive index for air-quality studies [6][7]. In this paper we present the SPEX instrument, which is a multi-angle spectropolarimeter that can comply with the polarimetric accuracy needed for characterizing aerosols in the Earth's atmosphere. We describe the implementation of spectral polarization modulation in a prototype instrument of SPEX and show results of ground based measurements from which aerosol microphysical properties are retrieved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28610699','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28610699"><span>An <span class="hlt">accurate</span> <span class="hlt">model</span> for the computation of the dose of protons in water.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Embriaco, A; Bellinzona, V E; Fontana, A; Rotondi, A</p> <p>2017-06-01</p> <p>The <span class="hlt">accurate</span> and fast calculation of the dose in proton radiation therapy is an essential ingredient for successful treatments. We propose a novel approach with a minimal number of parameters. The approach is based on the exact calculation of the electromagnetic part of the interaction, namely the Molière theory of the multiple Coulomb scattering for the transversal 1D projection and the Bethe-Bloch formula for the longitudinal stopping power profile, including a gaussian energy straggling. To this e.m. contribution the nuclear proton-nucleus interaction is added with a simple two-parameter <span class="hlt">model</span>. Then, the non gaussian lateral profile is used to calculate the radial dose distribution with a method that assumes the cylindrical symmetry of the distribution. The results, obtained with a fast C++ based computational code called MONET (<span class="hlt">MOdel</span> of ioN dosE for Therapy), are in very good agreement with the FLUKA MC code, within a few percent in the worst case. This study provides a new tool for fast dose calculation or verification, possibly for clinical use. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JFM...797..389E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JFM...797..389E"><span>Energy exchange analysis in droplet dynamics via the Navier-Stokes-Cahn-Hilliard <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Espath, L. F. R.; Sarmiento, A. F.; Vignal, P.; Varga, B. O. N.; Cortes, A. M. A.; Dalcin, L.; Calo, V. M.</p> <p>2016-06-01</p> <p>We develop the energy budget equation of the coupled Navier-Stokes-Cahn-Hilliard (NSCH) system. We use the NSCH equations to <span class="hlt">model</span> the dynamics of liquid droplets in a liquid continuum. Buoyancy effects are accounted for through the <span class="hlt">Boussinesq</span> assumption. We physically interpret each quantity involved in the energy exchange to further insight into the <span class="hlt">model</span>. Highly resolved simulations involving density-driven flows and merging of droplets allow us to analyze these energy budgets. In particular, we focus on the energy exchanges when droplets merge, and describe flow features relevant to this phenomenon. By comparing our numerical simulations to analytical predictions and experimental results available in the literature, we conclude that <span class="hlt">modeling</span> droplet dynamics within the framework of NSCH equations is a sensible approach worth further research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.6041..576L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.6041..576L"><span>Nondestructive evaluation using dipole <span class="hlt">model</span> analysis with a scan <span class="hlt">type</span> magnetic camera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Jinyi; Hwang, Jiseong</p> <p>2005-12-01</p> <p>Large structures such as nuclear power, thermal power, chemical and petroleum refining plants are drawing interest with regard to the economic aspect of extending component life in respect to the poor environment created by high pressure, high temperature, and fatigue, securing safety from corrosion and exceeding their designated life span. Therefore, technology that <span class="hlt">accurately</span> calculates and predicts degradation and defects of aging materials is extremely important. Among different methods available, nondestructive testing using magnetic methods is effective in predicting and evaluating defects on the surface of or surrounding ferromagnetic structures. It is important to estimate the distribution of magnetic field intensity for applicable magnetic methods relating to industrial nondestructive evaluation. A magnetic camera provides distribution of a quantitative magnetic field with a homogeneous lift-off and spatial resolution. It is possible to interpret the distribution of magnetic field when the dipole <span class="hlt">model</span> was introduced. This study proposed an algorithm for nondestructive evaluation using dipole <span class="hlt">model</span> analysis with a scan <span class="hlt">type</span> magnetic camera. The numerical and experimental considerations of the quantitative evaluation of several sizes and shapes of cracks using magnetic field images of the magnetic camera were examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AMTD....8.7697E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AMTD....8.7697E"><span>Can AERONET data be used to <span class="hlt">accurately</span> <span class="hlt">model</span> the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eissa, Y.; Blanc, P.; Wald, L.; Ghedira, H.</p> <p>2015-07-01</p> <p>Routine measurements of the beam irradiance at normal incidence (DNI) include the irradiance originating from within the extent of the solar disc only (DNIS) whose angular extent is 0.266° ± 1.7 %, and that from a larger circumsolar region, called the circumsolar normal irradiance (CSNI). This study investigates if the spectral aerosol optical properties of the AERONET stations are sufficient for an <span class="hlt">accurate</span> <span class="hlt">modelling</span> of the monochromatic DNIS and CSNI under cloud-free conditions in a desert environment. The data from an AERONET station in Abu Dhabi, United Arab Emirates, and a collocated Sun and Aureole Measurement (SAM) instrument which offers reference measurements of the monochromatic profile of solar radiance, were exploited. Using the AERONET data both the radiative transfer <span class="hlt">models</span> libRadtran and SMARTS offer an <span class="hlt">accurate</span> estimate of the monochromatic DNIS, with a relative root mean square error (RMSE) of 5 %, a relative bias of +1 % and acoefficient of determination greater than 0.97. After testing two configurations in SMARTS and three in libRadtran for <span class="hlt">modelling</span> the monochromatic CSNI, libRadtran exhibits the most <span class="hlt">accurate</span> results when the AERONET aerosol phase function is presented as a Two Term Henyey-Greenstein phase function. In this case libRadtran exhibited a relative RMSE and a bias of respectively 22 and -19 % and a coefficient of determination of 0.89. The results are promising and pave the way towards reporting the contribution of the broadband circumsolar irradiance to standard DNI measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JChPh.147b4105P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JChPh.147b4105P"><span>Beyond mean-field approximations for <span class="hlt">accurate</span> and computationally efficient <span class="hlt">models</span> of on-lattice chemical kinetics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pineda, M.; Stamatakis, M.</p> <p>2017-07-01</p> <p><span class="hlt">Modeling</span> the kinetics of surface catalyzed reactions is essential for the design of reactors and chemical processes. The majority of microkinetic <span class="hlt">models</span> employ mean-field approximations, which lead to an approximate description of catalytic kinetics by assuming spatially uncorrelated adsorbates. On the other hand, kinetic Monte Carlo (KMC) methods provide a discrete-space continuous-time stochastic formulation that enables an <span class="hlt">accurate</span> treatment of spatial correlations in the adlayer, but at a significant computation cost. In this work, we use the so-called cluster mean-field approach to develop higher order approximations that systematically increase the accuracy of kinetic <span class="hlt">models</span> by treating spatial correlations at a progressively higher level of detail. We further demonstrate our approach on a reduced <span class="hlt">model</span> for NO oxidation incorporating first nearest-neighbor lateral interactions and construct a sequence of approximations of increasingly higher accuracy, which we compare with KMC and mean-field. The latter is found to perform rather poorly, overestimating the turnover frequency by several orders of magnitude for this system. On the other hand, our approximations, while more computationally intense than the traditional mean-field treatment, still achieve tremendous computational savings compared to KMC simulations, thereby opening the way for employing them in multiscale <span class="hlt">modeling</span> frameworks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27260782','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27260782"><span><span class="hlt">Modeling</span> methodology for the <span class="hlt">accurate</span> and prompt prediction of symptomatic events in chronic diseases.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pagán, Josué; Risco-Martín, José L; Moya, José M; Ayala, José L</p> <p>2016-08-01</p> <p>Prediction of symptomatic crises in chronic diseases allows to take decisions before the symptoms occur, such as the intake of drugs to avoid the symptoms or the activation of medical alarms. The prediction horizon is in this case an important parameter in order to fulfill the pharmacokinetics of medications, or the time response of medical services. This paper presents a study about the prediction limits of a chronic disease with symptomatic crises: the migraine. For that purpose, this work develops a methodology to build predictive migraine <span class="hlt">models</span> and to improve these predictions beyond the limits of the initial <span class="hlt">models</span>. The maximum prediction horizon is analyzed, and its dependency on the selected features is studied. A strategy for <span class="hlt">model</span> selection is proposed to tackle the trade off between conservative but robust predictive <span class="hlt">models</span>, with respect to less <span class="hlt">accurate</span> predictions with higher horizons. The obtained results show a prediction horizon close to 40min, which is in the time range of the drug pharmacokinetics. Experiments have been performed in a realistic scenario where input data have been acquired in an ambulatory clinical study by the deployment of a non-intrusive Wireless Body Sensor Network. Our results provide an effective methodology for the selection of the future horizon in the development of prediction algorithms for diseases experiencing symptomatic crises. Copyright © 2016 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AMT.....8.5099E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AMT.....8.5099E"><span>Can AERONET data be used to <span class="hlt">accurately</span> <span class="hlt">model</span> the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eissa, Y.; Blanc, P.; Wald, L.; Ghedira, H.</p> <p>2015-12-01</p> <p>Routine measurements of the beam irradiance at normal incidence include the irradiance originating from within the extent of the solar disc only (DNIS), whose angular extent is 0.266° ± 1.7 %, and from a larger circumsolar region, called the circumsolar normal irradiance (CSNI). This study investigates whether the spectral aerosol optical properties of the AERONET stations are sufficient for an <span class="hlt">accurate</span> <span class="hlt">modelling</span> of the monochromatic DNIS and CSNI under cloud-free conditions in a desert environment. The data from an AERONET station in Abu Dhabi, United Arab Emirates, and the collocated Sun and Aureole Measurement instrument which offers reference measurements of the monochromatic profile of solar radiance were exploited. Using the AERONET data both the radiative transfer <span class="hlt">models</span> libRadtran and SMARTS offer an <span class="hlt">accurate</span> estimate of the monochromatic DNIS, with a relative root mean square error (RMSE) of 6 % and a coefficient of determination greater than 0.96. The observed relative bias obtained with libRadtran is +2 %, while that obtained with SMARTS is -1 %. After testing two configurations in SMARTS and three in libRadtran for <span class="hlt">modelling</span> the monochromatic CSNI, libRadtran exhibits the most <span class="hlt">accurate</span> results when the AERONET aerosol phase function is presented as a two-term Henyey-Greenstein phase function. In this case libRadtran exhibited a relative RMSE and a bias of respectively 27 and -24 % and a coefficient of determination of 0.882. Therefore, AERONET data may very well be used to <span class="hlt">model</span> the monochromatic DNIS and the monochromatic CSNI. The results are promising and pave the way towards reporting the contribution of the broadband circumsolar irradiance to standard measurements of the beam irradiance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920056932&hterms=data+types&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddata%2Btypes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920056932&hterms=data+types&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddata%2Btypes"><span>Differential tracking data <span class="hlt">types</span> for <span class="hlt">accurate</span> and efficient Mars planetary navigation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Edwards, C. D., Jr.; Kahn, R. D.; Folkner, W. M.; Border, J. S.</p> <p>1991-01-01</p> <p>Ways in which high-accuracy differential observations of two or more deep space vehicles can dramatically extend the power of earth-based tracking over conventional range and Doppler tracking are discussed. Two techniques - spacecraft-spacecraft differential very long baseline interferometry (S/C-S/C Delta(VLBI)) and same-beam interferometry (SBI) - are discussed. The tracking and navigation capabilities of conventional range, Doppler, and quasar-relative Delta(VLBI) are reviewed, and the S/C-S/C Delta (VLBI) and SBI <span class="hlt">types</span> are introduced. For each data <span class="hlt">type</span>, the formation of the observable is discussed, an error budget describing how physical error sources manifest themselves in the observable is presented, and potential applications of the technique for Space Exploration Initiative scenarios are examined. Requirements for spacecraft and ground systems needed to enable and optimize these <span class="hlt">types</span> of observations are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2550S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2550S"><span>An innovative early warning system for floods and operational risks in harbours</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smets, Steven; Bolle, Annelies; Mollaert, Justine; Buitrago, Saul; Gruwez, Vincent</p> <p>2016-04-01</p> <p>Early Warning Systems (EWS) are nowadays becoming fairly standard in river flood forecasting or in large scale hydrometeorological predictions. For complex coastal morphodynamic problems or in the vicinity of complex coastal structures, such as harbours, EWS are much less used because they are both technically and computationally still very challenging. To advance beyond the state-of-the-art, the EU FP7 project Risc-KIT (www.risc-kit.eu) is developing prototype EWS which address specifically these topics. This paper describes the prototype EWS which IMDC has developed for the case study site of the harbour of Zeebrugge. The harbour of Zeebrugge is the largest industrial seaport on the coast of Belgium, extending more than 3 km into the sea. Two long breakwaters provide shelter for the inner quays and docks for regular conditions and frequent storms. Extreme storms surges and waves can however still enter the harbour and create risks for the harbour operations and infrastructure. The prediction of the effects of storm surges and waves inside harbours are typically very complex and challenging, due to the need of different <span class="hlt">types</span> of numerical <span class="hlt">models</span> for representing all different physical processes. In general, waves inside harbours are a combination of locally wind generated waves and offshore wave penetration at the port entrance. During extreme conditions, the waves could overtop the quays and breakwaters and flood the port facilities. Outside a prediction environment, the conditions inside the harbour could be assessed by superimposing processes. The assessment can be carried out by using a combination of a spectral wave <span class="hlt">model</span> (i.e. SWAN) for the wind generated waves and a <span class="hlt">Boussinesq</span> <span class="hlt">type</span> wave <span class="hlt">model</span> (i.e. Mike 21 BW) for the wave penetration from offshore. Finally, a 2D hydrodynamic <span class="hlt">model</span> (i.e. TELEMAC) can be used to simulate the overland flooding inside the port facilities. To reproduce these processes in an EWS environment, an additional challenge is to cope</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=273336&keyword=estimator&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=273336&keyword=estimator&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Comparison of Varied Precipitation and Soil Data <span class="hlt">Types</span> for Use in Watershed <span class="hlt">Modeling</span>.</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The accuracy of water quality and quantity <span class="hlt">models</span> depends on calibration to ensure reliable simulations of streamflow, which in turn requires <span class="hlt">accurate</span> climatic forcing data. Precipitation is widely acknowledged to be the largest source of uncertainty in watershed <span class="hlt">modeling</span>, and so...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1000829-accurate-modeling-terrestrial-gamma-ray-background-homeland-security-applications','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1000829-accurate-modeling-terrestrial-gamma-ray-background-homeland-security-applications"><span><span class="hlt">Accurate</span> <span class="hlt">Modeling</span> of the Terrestrial Gamma-Ray Background for Homeland Security Applications</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Sandness, Gerald A.; Schweppe, John E.; Hensley, Walter K.</p> <p>2009-10-24</p> <p>Abstract–The Pacific Northwest National Laboratory has developed computer <span class="hlt">models</span> to simulate the use of radiation portal monitors to screen vehicles and cargo for the presence of illicit radioactive material. The gamma radiation emitted by the vehicles or cargo containers must often be measured in the presence of a relatively large gamma-ray background mainly due to the presence of potassium, uranium, and thorium (and progeny isotopes) in the soil and surrounding building materials. This large background is often a significant limit to the detection sensitivity for items of interest and must be <span class="hlt">modeled</span> <span class="hlt">accurately</span> for analyzing homeland security situations. Calculations ofmore » the expected gamma-ray emission from a disk of soil and asphalt were made using the Monte Carlo transport code MCNP and were compared to measurements made at a seaport with a high-purity germanium detector. Analysis revealed that the energy spectrum of the measured background could not be reproduced unless the <span class="hlt">model</span> included gamma rays coming from the ground out to distances of at least 300 m. The contribution from beyond about 50 m was primarily due to gamma rays that scattered in the air before entering the detectors rather than passing directly from the ground to the detectors. These skyshine gamma rays contribute tens of percent to the total gamma-ray spectrum, primarily at energies below a few hundred keV. The techniques that were developed to efficiently calculate the contributions from a large soil disk and a large air volume in a Monte Carlo simulation are described and the implications of skyshine in portal monitoring applications are discussed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017RSPTA.37670091C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017RSPTA.37670091C"><span>Hamiltonian <span class="hlt">models</span> for the propagation of irrotational surface gravity waves over a variable bottom</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Compelli, A.; Ivanov, R.; Todorov, M.</p> <p>2017-12-01</p> <p>A single incompressible, inviscid, irrotational fluid medium bounded by a free surface and varying bottom is considered. The Hamiltonian of the system is expressed in terms of the so-called Dirichlet-Neumann operators. The equations for the surface waves are presented in Hamiltonian form. Specific scaling of the variables is selected which leads to approximations of <span class="hlt">Boussinesq</span> and Korteweg-de Vries (KdV) <span class="hlt">types</span>, taking into account the effect of the slowly varying bottom. The arising KdV equation with variable coefficients is studied numerically when the initial condition is in the form of the one-soliton solution for the initial depth. This article is part of the theme issue 'Nonlinear water waves'.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29229791','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29229791"><span>Hamiltonian <span class="hlt">models</span> for the propagation of irrotational surface gravity waves over a variable bottom.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Compelli, A; Ivanov, R; Todorov, M</p> <p>2018-01-28</p> <p>A single incompressible, inviscid, irrotational fluid medium bounded by a free surface and varying bottom is considered. The Hamiltonian of the system is expressed in terms of the so-called Dirichlet-Neumann operators. The equations for the surface waves are presented in Hamiltonian form. Specific scaling of the variables is selected which leads to approximations of <span class="hlt">Boussinesq</span> and Korteweg-de Vries (KdV) <span class="hlt">types</span>, taking into account the effect of the slowly varying bottom. The arising KdV equation with variable coefficients is studied numerically when the initial condition is in the form of the one-soliton solution for the initial depth.This article is part of the theme issue 'Nonlinear water waves'. © 2017 The Author(s).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JPhCS.268a2008H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JPhCS.268a2008H"><span>Combining CFD simulations with blockoriented heatflow-network <span class="hlt">model</span> for prediction of photovoltaic energy-production</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haber, I. E.; Farkas, I.</p> <p>2011-01-01</p> <p>The exterior factors which influencing the working circumstances of photovoltaic modules are the irradiation, the optical air layer (Air Mass - AM), the irradiation angle, the environmental temperature and the cooling effect of the wind. The efficiency of photovoltaic (PV) devices is inversely proportional to the cell temperature and therefore the mounting of the PV modules can have a big affect on the cooling, due to wind flow-around and naturally convection. The construction of the modules could be described by a heatflow-network <span class="hlt">model</span>, and that can define the equation which determines the cells temperature. An equation like this can be solved as a block oriented <span class="hlt">model</span> with hybrid-analogue simulator such as Matlab-Simulink. In view of the flow field and the heat transfer, witch was calculated numerically, the heat transfer coefficients can be determined. Five inflow rates were set up for both pitched and flat roof cases, to let the trend of the heat transfer coefficient know, while these functions can be used for the Matlab/Simulink <span class="hlt">model</span>. To <span class="hlt">model</span> the free convection flows, the <span class="hlt">Boussinesq</span>-approximation were used, integrated into the Navier-Stokes equations and the energy equation. It has been found that under a constant solar heat gain, the air velocity around the modules and behind the pitched-roof mounted module is increasing, proportionately to the wind velocities, and as result the heat transfer coefficient increases linearly, and can be described by a function in both cases. To the block based <span class="hlt">model</span> the meteorological parameters and the results of the CFD simulations as single functions were attached. The final aim was to make a <span class="hlt">model</span> that could be used for planning photovoltaic systems, and define their <span class="hlt">accurate</span> performance for better sizing of an array of modules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ISPAr42W4...99Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ISPAr42W4...99Z"><span>Generating <span class="hlt">Accurate</span> 3d <span class="hlt">Models</span> of Architectural Heritage Structures Using Low-Cost Camera and Open Source Algorithms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zacharek, M.; Delis, P.; Kedzierski, M.; Fryskowska, A.</p> <p>2017-05-01</p> <p>These studies have been conductedusing non-metric digital camera and dense image matching algorithms, as non-contact methods of creating monuments documentation.In order toprocess the imagery, few open-source software and algorithms of generating adense point cloud from images have been executed. In the research, the OSM Bundler, VisualSFM software, and web application ARC3D were used. Images obtained for each of the investigated objects were processed using those applications, and then dense point clouds and textured 3D <span class="hlt">models</span> were created. As a result of post-processing, obtained <span class="hlt">models</span> were filtered and scaled.The research showedthat even using the open-source software it is possible toobtain <span class="hlt">accurate</span> 3D <span class="hlt">models</span> of structures (with an accuracy of a few centimeters), but for the purpose of documentation and conservation of cultural and historical heritage, such accuracy can be insufficient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22492247-accurate-thermoelastic-tensor-acoustic-velocities-nacl','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22492247-accurate-thermoelastic-tensor-acoustic-velocities-nacl"><span><span class="hlt">Accurate</span> thermoelastic tensor and acoustic velocities of NaCl</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Marcondes, Michel L., E-mail: michel@if.usp.br; Chemical Engineering and Material Science, University of Minnesota, Minneapolis, 55455; Shukla, Gaurav, E-mail: shukla@physics.umn.edu</p> <p></p> <p>Despite the importance of thermoelastic properties of minerals in geology and geophysics, their measurement at high pressures and temperatures are still challenging. Thus, ab initio calculations are an essential tool for predicting these properties at extreme conditions. Owing to the approximate description of the exchange-correlation energy, approximations used in calculations of vibrational effects, and numerical/methodological approximations, these methods produce systematic deviations. Hybrid schemes combining experimental data and theoretical results have emerged as a way to reconcile available information and offer more reliable predictions at experimentally inaccessible thermodynamics conditions. Here we introduce a method to improve the calculated thermoelastic tensor bymore » using highly <span class="hlt">accurate</span> thermal equation of state (EoS). The corrective scheme is general, applicable to crystalline solids with any symmetry, and can produce <span class="hlt">accurate</span> results at conditions where experimental data may not exist. We apply it to rock-salt-<span class="hlt">type</span> NaCl, a material whose structural properties have been challenging to describe <span class="hlt">accurately</span> by standard ab initio methods and whose acoustic/seismic properties are important for the gas and oil industry.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940012409','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940012409"><span><span class="hlt">Accurate</span> upwind methods for the Euler equations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Huynh, Hung T.</p> <p>1993-01-01</p> <p>A new class of piecewise linear methods for the numerical solution of the one-dimensional Euler equations of gas dynamics is presented. These methods are uniformly second-order <span class="hlt">accurate</span>, and can be considered as extensions of Godunov's scheme. With an appropriate definition of monotonicity preservation for the case of linear convection, it can be shown that they preserve monotonicity. Similar to Van Leer's MUSCL scheme, they consist of two key steps: a reconstruction step followed by an upwind step. For the reconstruction step, a monotonicity constraint that preserves uniform second-order accuracy is introduced. Computational efficiency is enhanced by devising a criterion that detects the 'smooth' part of the data where the constraint is redundant. The concept and coding of the constraint are simplified by the use of the median function. A slope steepening technique, which has no effect at smooth regions and can resolve a contact discontinuity in four cells, is described. As for the upwind step, existing and new methods are applied in a manner slightly different from those in the literature. These methods are derived by approximating the Euler equations via linearization and diagonalization. At a 'smooth' interface, Harten, Lax, and Van Leer's one intermediate state <span class="hlt">model</span> is employed. A modification for this <span class="hlt">model</span> that can resolve contact discontinuities is presented. Near a discontinuity, either this modified <span class="hlt">model</span> or a more <span class="hlt">accurate</span> one, namely, Roe's flux-difference splitting. is used. The current presentation of Roe's method, via the conceptually simple flux-vector splitting, not only establishes a connection between the two splittings, but also leads to an admissibility correction with no conditional statement, and an efficient approximation to Osher's approximate Riemann solver. These reconstruction and upwind steps result in schemes that are uniformly second-order <span class="hlt">accurate</span> and economical at smooth regions, and yield high resolution at discontinuities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018SSEle.139...31B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018SSEle.139...31B"><span><span class="hlt">Accurate</span> diode behavioral <span class="hlt">model</span> with reverse recovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Banáš, Stanislav; Divín, Jan; Dobeš, Josef; Paňko, Václav</p> <p>2018-01-01</p> <p>This paper deals with the comprehensive behavioral <span class="hlt">model</span> of p-n junction diode containing reverse recovery effect, applicable to all standard SPICE simulators supporting Verilog-A language. The <span class="hlt">model</span> has been successfully used in several production designs, which require its full complexity, robustness and set of tuning parameters comparable with standard compact SPICE diode <span class="hlt">model</span>. The <span class="hlt">model</span> is like standard compact <span class="hlt">model</span> scalable with area and temperature and can be used as a stand-alone diode or as a part of more complex device macro-<span class="hlt">model</span>, e.g. LDMOS, JFET, bipolar transistor. The paper briefly presents the state of the art followed by the chapter describing the <span class="hlt">model</span> development and achieved solutions. During precise <span class="hlt">model</span> verification some of them were found non-robust or poorly converging and replaced by more robust solutions, demonstrated in the paper. The measurement results of different technologies and different devices compared with a simulation using the new behavioral <span class="hlt">model</span> are presented as the <span class="hlt">model</span> validation. The comparison of <span class="hlt">model</span> validation in time and frequency domains demonstrates that the implemented reverse recovery effect with correctly extracted parameters improves the <span class="hlt">model</span> simulation results not only in switching from ON to OFF state, which is often published, but also its impedance/admittance frequency dependency in GHz range. Finally the <span class="hlt">model</span> parameter extraction and the comparison with SPICE compact <span class="hlt">models</span> containing reverse recovery effect is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H31E1560L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H31E1560L"><span>A Budyko-<span class="hlt">type</span> <span class="hlt">Model</span> for Human Water Consumption</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lei, X.; Zhao, J.; Wang, D.; Sivapalan, M.</p> <p>2017-12-01</p> <p>With the expansion of human water footprint, water crisis is no longer only a conflict or competition for water between different economic sectors, but also increasingly between human and the environment. In order to describe the emergent dynamics and patterns of the interaction, a theoretical framework that encapsulates the physical and societal controls impacting human water consumption is needed. In traditional hydrology, Budyko-<span class="hlt">type</span> <span class="hlt">models</span> are simple but efficient descriptions of vegetation-mediated hydrologic cycle in catchments, i.e., the partitioning of mean annual precipitation into runoff and evapotranspiration. Plant water consumption plays a crucial role in the process. Hypothesized similarities between human-water and vegetation-water interactions, including water demand, constraints and system functioning, give the idea of corresponding Budyko-<span class="hlt">type</span> framework for human water consumption at the catchment scale. Analogous to variables of Budyko-<span class="hlt">type</span> <span class="hlt">models</span> for hydrologic cycle, water demand, water consumption, environmental water use and available water are corresponding to potential evaporation, actual evaporation, runoff and precipitation respectively. Human water consumption data, economic and hydro-meteorological data for 51 human-impacted catchments and 10 major river basins in China are assembled to look for the existence of a Budyko-<span class="hlt">type</span> relationship for human water consumption, and to seek explanations for the spread in the observed relationship. Guided by this, a Budyko-<span class="hlt">type</span> analytical <span class="hlt">model</span> is derived based on application of an optimality principle, that of maximum water benefit. The <span class="hlt">model</span> derived has the same functional form and mathematical features as those that apply for the original Budyko <span class="hlt">model</span>. Parameters of the new Budyko-<span class="hlt">type</span> <span class="hlt">model</span> for human consumption are linked to economic and social factors. The results of this paper suggest that the functioning of both social and hydrologic subsystems within catchment systems can be explored within</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015RaPC..116..231I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015RaPC..116..231I"><span><span class="hlt">Accurate</span> Monte Carlo <span class="hlt">modeling</span> of cyclotrons for optimization of shielding and activation calculations in the biomedical field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Infantino, Angelo; Marengo, Mario; Baschetti, Serafina; Cicoria, Gianfranco; Longo Vaschetto, Vittorio; Lucconi, Giulia; Massucci, Piera; Vichi, Sara; Zagni, Federico; Mostacci, Domiziano</p> <p>2015-11-01</p> <p>Biomedical cyclotrons for production of Positron Emission Tomography (PET) radionuclides and radiotherapy with hadrons or ions are widely diffused and established in hospitals as well as in industrial facilities and research sites. Guidelines for site planning and installation, as well as for radiation protection assessment, are given in a number of international documents; however, these well-established guides typically offer analytic methods of calculation of both shielding and materials activation, in approximate or idealized geometry set up. The availability of Monte Carlo codes with <span class="hlt">accurate</span> and up-to-date libraries for transport and interactions of neutrons and charged particles at energies below 250 MeV, together with the continuously increasing power of nowadays computers, makes systematic use of simulations with realistic geometries possible, yielding equipment and site specific evaluation of the source terms, shielding requirements and all quantities relevant to radiation protection. In this work, the well-known Monte Carlo code FLUKA was used to simulate two representative <span class="hlt">models</span> of cyclotron for PET radionuclides production, including their targetry; and one <span class="hlt">type</span> of proton therapy cyclotron including the energy selection system. Simulations yield estimates of various quantities of radiological interest, including the effective dose distribution around the equipment, the effective number of neutron produced per incident proton and the activation of target materials, the structure of the cyclotron, the energy degrader, the vault walls and the soil. The <span class="hlt">model</span> was validated against experimental measurements and comparison with well-established reference data. Neutron ambient dose equivalent H*(10) was measured around a GE PETtrace cyclotron: an average ratio between experimental measurement and simulations of 0.99±0.07 was found. Saturation yield of 18F, produced by the well-known 18O(p,n)18F reaction, was calculated and compared with the IAEA recommended</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JAMES..10..908M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JAMES..10..908M"><span>An <span class="hlt">Accurate</span> Fire-Spread Algorithm in the Weather Research and Forecasting <span class="hlt">Model</span> Using the Level-Set Method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muñoz-Esparza, Domingo; Kosović, Branko; Jiménez, Pedro A.; Coen, Janice L.</p> <p>2018-04-01</p> <p>The level-set method is typically used to track and propagate the fire perimeter in wildland fire <span class="hlt">models</span>. Herein, a high-order level-set method using fifth-order WENO scheme for the discretization of spatial derivatives and third-order explicit Runge-Kutta temporal integration is implemented within the Weather Research and Forecasting <span class="hlt">model</span> wildland fire physics package, WRF-Fire. The algorithm includes solution of an additional partial differential equation for level-set reinitialization. The accuracy of the fire-front shape and rate of spread in uncoupled simulations is systematically analyzed. It is demonstrated that the common implementation used by level-set-based wildfire <span class="hlt">models</span> yields to rate-of-spread errors in the range 10-35% for typical grid sizes (Δ = 12.5-100 m) and considerably underestimates fire area. Moreover, the amplitude of fire-front gradients in the presence of explicitly resolved turbulence features is systematically underestimated. In contrast, the new WRF-Fire algorithm results in rate-of-spread errors that are lower than 1% and that become nearly grid independent. Also, the underestimation of fire area at the sharp transition between the fire front and the lateral flanks is found to be reduced by a factor of ≈7. A hybrid-order level-set method with locally reduced artificial viscosity is proposed, which substantially alleviates the computational cost associated with high-order discretizations while preserving accuracy. Simulations of the Last Chance wildfire demonstrate additional benefits of high-order <span class="hlt">accurate</span> level-set algorithms when dealing with complex fuel heterogeneities, enabling propagation across narrow fuel gaps and more <span class="hlt">accurate</span> fire backing over the lee side of no fuel clusters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19938439','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19938439"><span><span class="hlt">Modelling</span> healthcare systems with phase-<span class="hlt">type</span> distributions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fackrell, Mark</p> <p>2009-03-01</p> <p>Phase-<span class="hlt">type</span> distributions constitute a very versatile class of distributions. They have been used in a wide range of stochastic <span class="hlt">modelling</span> applications in areas as diverse as telecommunications, finance, biostatistics, queueing theory, drug kinetics, and survival analysis. Their use in <span class="hlt">modelling</span> systems in the healthcare industry, however, has so far been limited. In this paper we introduce phase-<span class="hlt">type</span> distributions, give a survey of where they have been used in the healthcare industry, and propose some ideas on how they could be further utilized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhCS.890a2142S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhCS.890a2142S"><span>A bivariate <span class="hlt">model</span> for analyzing recurrent multi-<span class="hlt">type</span> automobile failures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sunethra, A. A.; Sooriyarachchi, M. R.</p> <p>2017-09-01</p> <p>The failure mechanism in an automobile can be defined as a system of multi-<span class="hlt">type</span> recurrent failures where failures can occur due to various multi-<span class="hlt">type</span> failure modes and these failures are repetitive such that more than one failure can occur from each failure mode. In analysing such automobile failures, both the time and <span class="hlt">type</span> of the failure serve as response variables. However, these two response variables are highly correlated with each other since the timing of failures has an association with the mode of the failure. When there are more than one correlated response variables, the fitting of a multivariate <span class="hlt">model</span> is more preferable than separate univariate <span class="hlt">models</span>. Therefore, a bivariate <span class="hlt">model</span> of time and <span class="hlt">type</span> of failure becomes appealing for such automobile failure data. When there are multiple failure observations pertaining to a single automobile, such data cannot be treated as independent data because failure instances of a single automobile are correlated with each other while failures among different automobiles can be treated as independent. Therefore, this study proposes a bivariate <span class="hlt">model</span> consisting time and <span class="hlt">type</span> of failure as responses adjusted for correlated data. The proposed <span class="hlt">model</span> was formulated following the approaches of shared parameter <span class="hlt">models</span> and random effects <span class="hlt">models</span> for joining the responses and for representing the correlated data respectively. The proposed <span class="hlt">model</span> is applied to a sample of automobile failures with three <span class="hlt">types</span> of failure modes and up to five failure recurrences. The parametric distributions that were suitable for the two responses of time to failure and <span class="hlt">type</span> of failure were Weibull distribution and multinomial distribution respectively. The proposed bivariate <span class="hlt">model</span> was programmed in SAS Procedure Proc NLMIXED by user programming appropriate likelihood functions. The performance of the bivariate <span class="hlt">model</span> was compared with separate univariate <span class="hlt">models</span> fitted for the two responses and it was identified that better performance is secured by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26125384','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26125384"><span><span class="hlt">Accurate</span> quantification of fluorescent targets within turbid media based on a decoupled fluorescence Monte Carlo <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Deng, Yong; Luo, Zhaoyang; Jiang, Xu; Xie, Wenhao; Luo, Qingming</p> <p>2015-07-01</p> <p>We propose a method based on a decoupled fluorescence Monte Carlo <span class="hlt">model</span> for constructing fluorescence Jacobians to enable <span class="hlt">accurate</span> quantification of fluorescence targets within turbid media. The effectiveness of the proposed method is validated using two cylindrical phantoms enclosing fluorescent targets within homogeneous and heterogeneous background media. The results demonstrate that our method can recover relative concentrations of the fluorescent targets with higher accuracy than the perturbation fluorescence Monte Carlo method. This suggests that our method is suitable for quantitative fluorescence diffuse optical tomography, especially for in vivo imaging of fluorophore targets for diagnosis of different diseases and abnormalities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3970899','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3970899"><span>Ensemble MD simulations restrained via crystallographic data: <span class="hlt">Accurate</span> structure leads to <span class="hlt">accurate</span> dynamics</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xue, Yi; Skrynnikov, Nikolai R</p> <p>2014-01-01</p> <p>Currently, the best existing molecular dynamics (MD) force fields cannot <span class="hlt">accurately</span> reproduce the global free-energy minimum which realizes the experimental protein structure. As a result, long MD trajectories tend to drift away from the starting coordinates (e.g., crystallographic structures). To address this problem, we have devised a new simulation strategy aimed at protein crystals. An MD simulation of protein crystal is essentially an ensemble simulation involving multiple protein molecules in a crystal unit cell (or a block of unit cells). To ensure that average protein coordinates remain correct during the simulation, we introduced crystallography-based restraints into the MD protocol. Because these restraints are aimed at the ensemble-average structure, they have only minimal impact on conformational dynamics of the individual protein molecules. So long as the average structure remains reasonable, the proteins move in a native-like fashion as dictated by the original force field. To validate this approach, we have used the data from solid-state NMR spectroscopy, which is the orthogonal experimental technique uniquely sensitive to protein local dynamics. The new method has been tested on the well-established <span class="hlt">model</span> protein, ubiquitin. The ensemble-restrained MD simulations produced lower crystallographic R factors than conventional simulations; they also led to more <span class="hlt">accurate</span> predictions for crystallographic temperature factors, solid-state chemical shifts, and backbone order parameters. The predictions for 15N R1 relaxation rates are at least as <span class="hlt">accurate</span> as those obtained from conventional simulations. Taken together, these results suggest that the presented trajectories may be among the most realistic protein MD simulations ever reported. In this context, the ensemble restraints based on high-resolution crystallographic data can be viewed as protein-specific empirical corrections to the standard force fields. PMID:24452989</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoJI.210..105A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoJI.210..105A"><span>A gauged finite-element potential formulation for <span class="hlt">accurate</span> inductive and galvanic <span class="hlt">modelling</span> of 3-D electromagnetic problems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ansari, S. M.; Farquharson, C. G.; MacLachlan, S. P.</p> <p>2017-07-01</p> <p>In this paper, a new finite-element solution to the potential formulation of the geophysical electromagnetic (EM) problem that explicitly implements the Coulomb gauge, and that <span class="hlt">accurately</span> computes the potentials and hence inductive and galvanic components, is proposed. The <span class="hlt">modelling</span> scheme is based on using unstructured tetrahedral meshes for domain subdivision, which enables both realistic Earth <span class="hlt">models</span> of complex geometries to be considered and efficient spatially variable refinement of the mesh to be done. For the finite-element discretization edge and nodal elements are used for approximating the vector and scalar potentials respectively. The issue of non-unique, incorrect potentials from the numerical solution of the usual incomplete-gauged potential system is demonstrated for a benchmark <span class="hlt">model</span> from the literature that uses an electric-<span class="hlt">type</span> EM source, through investigating the interface continuity conditions for both the normal and tangential components of the potential vectors, and by showing inconsistent results obtained from iterative and direct linear equation solvers. By explicitly introducing the Coulomb gauge condition as an extra equation, and by augmenting the Helmholtz equation with the gradient of a Lagrange multiplier, an explicitly gauged system for the potential formulation is formed. The solution to the discretized form of this system is validated for the above-mentioned example and for another classic example that uses a magnetic EM source. In order to stabilize the iterative solution of the gauged system, a block diagonal pre-conditioning scheme that is based upon the Schur complement of the potential system is used. For all examples, both the iterative and direct solvers produce the same responses for the potentials, demonstrating the uniqueness of the numerical solution for the potentials and fixing the problems with the interface conditions between cells observed for the incomplete-gauged system. These solutions of the gauged system also</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1816432K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1816432K"><span>Application of thin plate splines for <span class="hlt">accurate</span> regional ionosphere <span class="hlt">modeling</span> with multi-GNSS data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krypiak-Gregorczyk, Anna; Wielgosz, Pawel; Borkowski, Andrzej</p> <p>2016-04-01</p> <p>GNSS-derived regional ionosphere <span class="hlt">models</span> are widely used in both precise positioning, ionosphere and space weather studies. However, their accuracy is often not sufficient to support precise positioning, RTK in particular. In this paper, we presented new approach that uses solely carrier phase multi-GNSS observables and thin plate splines (TPS) for <span class="hlt">accurate</span> ionospheric TEC <span class="hlt">modeling</span>. TPS is a closed solution of a variational problem minimizing both the sum of squared second derivatives of a smoothing function and the deviation between data points and this function. This approach is used in UWM-rt1 regional ionosphere <span class="hlt">model</span> developed at UWM in Olsztyn. The <span class="hlt">model</span> allows for providing ionospheric TEC maps with high spatial and temporal resolutions - 0.2x0.2 degrees and 2.5 minutes, respectively. For TEC estimation, EPN and EUPOS reference station data is used. The maps are available with delay of 15-60 minutes. In this paper we compare the performance of UWM-rt1 <span class="hlt">model</span> with IGS global and CODE regional ionosphere maps during ionospheric storm that took place on March 17th, 2015. During this storm, the TEC level over Europe doubled comparing to earlier quiet days. The performance of the UWM-rt1 <span class="hlt">model</span> was validated by (a) comparison to reference double-differenced ionospheric corrections over selected baselines, and (b) analysis of post-fit residuals to calibrated carrier phase geometry-free observational arcs at selected test stations. The results show a very good performance of UWM-rt1 <span class="hlt">model</span>. The obtained post-fit residuals in case of UWM maps are lower by one order of magnitude comparing to IGS maps. The accuracy of UWM-rt1 -derived TEC maps is estimated at 0.5 TECU. This may be directly translated to the user positioning domain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhRvL.120n5301X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhRvL.120n5301X"><span>Crystal Graph Convolutional Neural Networks for an <span class="hlt">Accurate</span> and Interpretable Prediction of Material Properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Tian; Grossman, Jeffrey C.</p> <p>2018-04-01</p> <p>The use of machine learning methods for accelerating the design of crystalline materials usually requires manually constructed feature vectors or complex transformation of atom coordinates to input the crystal structure, which either constrains the <span class="hlt">model</span> to certain crystal <span class="hlt">types</span> or makes it difficult to provide chemical insights. Here, we develop a crystal graph convolutional neural networks framework to directly learn material properties from the connection of atoms in the crystal, providing a universal and interpretable representation of crystalline materials. Our method provides a highly <span class="hlt">accurate</span> prediction of density functional theory calculated properties for eight different properties of crystals with various structure <span class="hlt">types</span> and compositions after being trained with 1 04 data points. Further, our framework is interpretable because one can extract the contributions from local chemical environments to global properties. Using an example of perovskites, we show how this information can be utilized to discover empirical rules for materials design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4712143','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4712143"><span>A Biomechanical <span class="hlt">Model</span> of the Scapulothoracic Joint to <span class="hlt">Accurately</span> Capture Scapular Kinematics during Shoulder Movements</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Seth, Ajay; Matias, Ricardo; Veloso, António P.; Delp, Scott L.</p> <p>2016-01-01</p> <p>The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal <span class="hlt">models</span> can improve motion capture accuracy by reducing the space of possible joint movements, and <span class="hlt">models</span> are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body <span class="hlt">model</span> of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This <span class="hlt">model</span> describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual’s anthropometry. We compared the <span class="hlt">model</span> to “gold standard” bone-pin kinematics collected during three shoulder tasks and found <span class="hlt">modeled</span> scapular kinematics to be <span class="hlt">accurate</span> to within 2mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the <span class="hlt">model</span> reduced kinematic variability due to noise by 65% compared to Euler angles computed without the <span class="hlt">model</span>. Our scapulothoracic joint <span class="hlt">model</span> can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint <span class="hlt">model</span> is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim <span class="hlt">models</span>. PMID:26734761</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26734761','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26734761"><span>A Biomechanical <span class="hlt">Model</span> of the Scapulothoracic Joint to <span class="hlt">Accurately</span> Capture Scapular Kinematics during Shoulder Movements.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Seth, Ajay; Matias, Ricardo; Veloso, António P; Delp, Scott L</p> <p>2016-01-01</p> <p>The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal <span class="hlt">models</span> can improve motion capture accuracy by reducing the space of possible joint movements, and <span class="hlt">models</span> are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body <span class="hlt">model</span> of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This <span class="hlt">model</span> describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual's anthropometry. We compared the <span class="hlt">model</span> to "gold standard" bone-pin kinematics collected during three shoulder tasks and found <span class="hlt">modeled</span> scapular kinematics to be <span class="hlt">accurate</span> to within 2 mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the <span class="hlt">model</span> reduced kinematic variability due to noise by 65% compared to Euler angles computed without the <span class="hlt">model</span>. Our scapulothoracic joint <span class="hlt">model</span> can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint <span class="hlt">model</span> is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017TMP...192.1097G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017TMP...192.1097G"><span>Kulish-Sklyanin-<span class="hlt">type</span> <span class="hlt">models</span>: Integrability and reductions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gerdjikov, V. S.</p> <p>2017-08-01</p> <p>We start with a Riemann-Hilbert problem ( RHP) related to BD.I- <span class="hlt">type</span> symmetric spaces SO(2 r + 1)/ S( O(2 r - 2 s+1) ⊗ O(2 s)), s ≥ 1. We consider two RHPs: the first is formulated on the real axis R in the complex-λ plane; the second, on R ⊗ iR. The first RHP for s = 1 allows solving the Kulish-Sklyanin (KS) <span class="hlt">model</span>; the second RHP is related to a new <span class="hlt">type</span> of KS <span class="hlt">model</span>. We consider an important example of nontrivial deep reductions of the KS <span class="hlt">model</span> and show its effect on the scattering matrix. In particular, we obtain new two-component nonlinear Schrödinger equations. Finally, using the Wronski relations, we show that the inverse scattering method for KS <span class="hlt">models</span> can be understood as generalized Fourier transforms. We thus find a way to characterize all the fundamental properties of KS <span class="hlt">models</span> including the hierarchy of equations and the hierarchy of their Hamiltonian structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15931680','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15931680"><span>Antenna <span class="hlt">modeling</span> considerations for <span class="hlt">accurate</span> SAR calculations in human phantoms in close proximity to GSM cellular base station antennas.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Wyk, Marnus J; Bingle, Marianne; Meyer, Frans J C</p> <p>2005-09-01</p> <p>International bodies such as International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute for Electrical and Electronic Engineering (IEEE) make provision for human exposure assessment based on SAR calculations (or measurements) and basic restrictions. In the case of base station exposure this is mostly applicable to occupational exposure scenarios in the very near field of these antennas where the conservative reference level criteria could be unnecessarily restrictive. This study presents a variety of critical aspects that need to be considered when calculating SAR in a human body close to a mobile phone base station antenna. A hybrid FEM/MoM technique is proposed as a suitable numerical method to obtain <span class="hlt">accurate</span> results. The verification of the FEM/MoM implementation has been presented in a previous publication; the focus of this study is an investigation into the detail that must be included in a numerical <span class="hlt">model</span> of the antenna, to <span class="hlt">accurately</span> represent the real-world scenario. This is accomplished by comparing numerical results to measurements for a generic GSM base station antenna and appropriate, representative canonical and human phantoms. The results show that it is critical to take the disturbance effect of the human phantom (a large conductive body) on the base station antenna into account when the antenna-phantom spacing is less than 300 mm. For these small spacings, the antenna structure must be <span class="hlt">modeled</span> in detail. The conclusion is that it is feasible to calculate, using the proposed techniques and methodology, <span class="hlt">accurate</span> occupational compliance zones around base station antennas based on a SAR profile and basic restriction guidelines. (c) 2005 Wiley-Liss, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA092898','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA092898"><span>Stochastic Lanchester-<span class="hlt">type</span> Combat <span class="hlt">Models</span> I.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1979-10-01</p> <p>necessarily hold when the attrition rates become non- linear in b and/or r. 13 iL 4. OTHER COMBAT <span class="hlt">MODELS</span> In this section we briefly describe how other...AD-A092 898 FLORIDA STATE UNIV TALLAHASSEE DEPT OF STATISTICS F/6 12/2 STOCHASTIC LANCHESTER-<span class="hlt">TYPE</span> COMBAT <span class="hlt">MODELS</span> I.(U) OCT 79 L BILLARD N62271-79-M...COMBAT <span class="hlt">MODELS</span> I by L. BILLARD October 1979 Approved for public release; distribution unlimited. Prepared for: Naval Postgraduate School Monterey, CA 93940</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OcMod.106...12T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OcMod.106...12T"><span>Generation of long subharmonic internal waves by surface waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tahvildari, Navid; Kaihatu, James M.; Saric, William S.</p> <p>2016-10-01</p> <p>A new set of <span class="hlt">Boussinesq</span> equations is derived to study the nonlinear interactions between long waves in a two-layer fluid. The fluid layers are assumed to be homogeneous, inviscid, incompressible, and immiscible. Based on the <span class="hlt">Boussinesq</span> equations, an analytical <span class="hlt">model</span> is developed using a second-order perturbation theory and applied to examine the transient evolution of a resonant triad composed of a surface wave and two oblique subharmonic internal waves. Wave damping due to weak viscosity in both layers is considered. The <span class="hlt">Boussinesq</span> equations and the analytical <span class="hlt">model</span> are verified. In contrast to previous studies which focus on short internal waves, we examine long waves and investigate some previously unexplored characteristics of this class of triad interaction. In viscous fluids, surface wave amplitudes must be larger than a threshold to overcome viscous damping and trigger internal waves. The dependency of this critical amplitude as well as the growth and damping rates of internal waves on important parameters in a two-fluid system, namely the directional angle of the internal waves, depth, density, and viscosity ratio of the fluid layers, and surface wave amplitude and frequency is investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/45370','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/45370"><span>Fuel consumption <span class="hlt">models</span> for pine flatwoods fuel <span class="hlt">types</span> in the southeastern United States</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Clinton S. Wright</p> <p>2013-01-01</p> <p><span class="hlt">Modeling</span> fire effects, including terrestrial and atmospheric carbon fluxes and pollutant emissions during wildland fires, requires <span class="hlt">accurate</span> predictions of fuel consumption. Empirical <span class="hlt">models</span> were developed for predicting fuel consumption from fuel and environmental measurements on a series of operational prescribed fires in pine flatwoods ecosystems in the southeastern...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740020296','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740020296"><span>On numerically <span class="hlt">accurate</span> finite element</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nagtegaal, J. C.; Parks, D. M.; Rice, J. R.</p> <p>1974-01-01</p> <p>A general criterion for testing a mesh with topologically similar repeat units is given, and the analysis shows that only a few conventional element <span class="hlt">types</span> and arrangements are, or can be made suitable for computations in the fully plastic range. Further, a new variational principle, which can easily and simply be incorporated into an existing finite element program, is presented. This allows <span class="hlt">accurate</span> computations to be made even for element designs that would not normally be suitable. Numerical results are given for three plane strain problems, namely pure bending of a beam, a thick-walled tube under pressure, and a deep double edge cracked tensile specimen. The effects of various element designs and of the new variational procedure are illustrated. Elastic-plastic computation at finite strain are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22266176-generalized-stoner-wohlfarth-model-accurately-describing-switching-processes-pseudo-single-ferromagnetic-particles','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22266176-generalized-stoner-wohlfarth-model-accurately-describing-switching-processes-pseudo-single-ferromagnetic-particles"><span>Generalized Stoner-Wohlfarth <span class="hlt">model</span> <span class="hlt">accurately</span> describing the switching processes in pseudo-single ferromagnetic particles</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Cimpoesu, Dorin, E-mail: cdorin@uaic.ro; Stoleriu, Laurentiu; Stancu, Alexandru</p> <p>2013-12-14</p> <p>We propose a generalized Stoner-Wohlfarth (SW) <span class="hlt">type</span> <span class="hlt">model</span> to describe various experimentally observed angular dependencies of the switching field in non-single-domain magnetic particles. Because the nonuniform magnetic states are generally characterized by complicated spin configurations with no simple analytical description, we maintain the macrospin hypothesis and we phenomenologically include the effects of nonuniformities only in the anisotropy energy, preserving as much as possible the elegance of SW <span class="hlt">model</span>, the concept of critical curve and its geometric interpretation. We compare the results obtained with our <span class="hlt">model</span> with full micromagnetic simulations in order to evaluate the performance and limits of our approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDH17001M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDH17001M"><span>Wildfire simulation using LES with synthetic-velocity SGS <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McDonough, J. M.; Tang, Tingting</p> <p>2016-11-01</p> <p>Wildland fires are becoming more prevalent and intense worldwide as climate change leads to warmer, drier conditions; and large-eddy simulation (LES) is receiving increasing attention for fire spread predictions as computing power continues to improve (see, e.g.,). We report results from wildfire simulations over general terrain employing implicit LES for solution of the incompressible Navier-Stokes (N.-S.) and thermal energy equations with <span class="hlt">Boussinesq</span> approximation, altered with Darcy, Forchheimer and Brinkman extensions, to represent forested regions as porous media with varying (in both space and time) porosity and permeability. We focus on subgrid-scale (SGS) behaviors computed with a synthetic-velocity <span class="hlt">model</span>, a discrete dynamical system, based on the poor man's N.-S. equations and investigate the ability of this <span class="hlt">model</span> to produce fire whirls (tornadoes of fire) at the (unresolved) SGS level. Professor, Mechanical Engineering and Mathematics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.B14A..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.B14A..05K"><span>Development of a New <span class="hlt">Model</span> for <span class="hlt">Accurate</span> Prediction of Cloud Water Deposition on Vegetation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Katata, G.; Nagai, H.; Wrzesinsky, T.; Klemm, O.; Eugster, W.; Burkard, R.</p> <p>2006-12-01</p> <p>Scarcity of water resources in arid and semi-arid areas is of great concern in the light of population growth and food shortages. Several experiments focusing on cloud (fog) water deposition on the land surface suggest that cloud water plays an important role in water resource in such regions. A one-dimensional vegetation <span class="hlt">model</span> including the process of cloud water deposition on vegetation has been developed to better predict cloud water deposition on the vegetation. New schemes to calculate capture efficiency of leaf, cloud droplet size distribution, and gravitational flux of cloud water were incorporated in the <span class="hlt">model</span>. <span class="hlt">Model</span> calculations were compared with the data acquired at the Norway spruce forest at the Waldstein site, Germany. High performance of the <span class="hlt">model</span> was confirmed by comparisons of calculated net radiation, sensible and latent heat, and cloud water fluxes over the forest with measurements. The present <span class="hlt">model</span> provided a better prediction of measured turbulent and gravitational fluxes of cloud water over the canopy than the Lovett <span class="hlt">model</span>, which is a commonly used cloud water deposition <span class="hlt">model</span>. Detailed calculations of evapotranspiration and of turbulent exchange of heat and water vapor within the canopy and the modifications are necessary for <span class="hlt">accurate</span> prediction of cloud water deposition. Numerical experiments to examine the dependence of cloud water deposition on the vegetation species (coniferous and broad-leaved trees, flat and cylindrical grasses) and structures (Leaf Area Index (LAI) and canopy height) are performed using the presented <span class="hlt">model</span>. The results indicate that the differences of leaf shape and size have a large impact on cloud water deposition. Cloud water deposition also varies with the growth of vegetation and seasonal change of LAI. We found that the coniferous trees whose height and LAI are 24 m and 2.0 m2m-2, respectively, produce the largest amount of cloud water deposition in all combinations of vegetation species and structures in the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.G51A0737A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.G51A0737A"><span>Estimating Gravity Biases with Wavelets in Support of a 1-cm <span class="hlt">Accurate</span> Geoid <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahlgren, K.; Li, X.</p> <p>2017-12-01</p> <p>Systematic errors that reside in surface gravity datasets are one of the major hurdles in constructing a high-accuracy geoid <span class="hlt">model</span> at high resolutions. The National Oceanic and Atmospheric Administration's (NOAA) National Geodetic Survey (NGS) has an extensive historical surface gravity dataset consisting of approximately 10 million gravity points that are known to have systematic biases at the mGal level (Saleh et al. 2013). As most relevant metadata is absent, estimating and removing these errors to be consistent with a global geopotential <span class="hlt">model</span> and airborne data in the corresponding wavelength is quite a difficult endeavor. However, this is crucial to support a 1-cm <span class="hlt">accurate</span> geoid <span class="hlt">model</span> for the United States. With recently available independent gravity information from GRACE/GOCE and airborne gravity from the NGS Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project, several different methods of bias estimation are investigated which utilize radial basis functions and wavelet decomposition. We estimate a surface gravity value by incorporating a satellite gravity <span class="hlt">model</span>, airborne gravity data, and forward-<span class="hlt">modeled</span> topography at wavelet levels according to each dataset's spatial wavelength. Considering the estimated gravity values over an entire gravity survey, an estimate of the bias and/or correction for the entire survey can be found and applied. In order to assess the accuracy of each bias estimation method, two techniques are used. First, each bias estimation method is used to predict the bias for two high-quality (unbiased and high accuracy) geoid slope validation surveys (GSVS) (Smith et al. 2013 & Wang et al. 2017). Since these surveys are unbiased, the various bias estimation methods should reflect that and provide an absolute accuracy metric for each of the bias estimation methods. Secondly, the corrected gravity datasets from each of the bias estimation methods are used to build a geoid <span class="hlt">model</span>. The accuracy of each geoid <span class="hlt">model</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhRvE..77d1911W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhRvE..77d1911W"><span>Stochastic analysis of a pulse-<span class="hlt">type</span> prey-predator <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Y.; Zhu, W. Q.</p> <p>2008-04-01</p> <p>A stochastic Lotka-Volterra <span class="hlt">model</span>, a so-called pulse-<span class="hlt">type</span> <span class="hlt">model</span>, for the interaction between two species and their random natural environment is investigated. The effect of a random environment is <span class="hlt">modeled</span> as random pulse trains in the birth rate of the prey and the death rate of the predator. The generalized cell mapping method is applied to calculate the probability distributions of the species populations at a state of statistical quasistationarity. The time evolution of the population densities is studied, and the probability of the near extinction time, from an initial state to a critical state, is obtained. The effects on the ecosystem behaviors of the prey self-competition term and of the pulse mean arrival rate are also discussed. Our results indicate that the proposed pulse-<span class="hlt">type</span> <span class="hlt">model</span> shows obviously distinguishable characteristics from a Gaussian-<span class="hlt">type</span> <span class="hlt">model</span>, and may confer a significant advantage for <span class="hlt">modeling</span> the prey-predator system under discrete environmental fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18517660','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18517660"><span>Stochastic analysis of a pulse-<span class="hlt">type</span> prey-predator <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Y; Zhu, W Q</p> <p>2008-04-01</p> <p>A stochastic Lotka-Volterra <span class="hlt">model</span>, a so-called pulse-<span class="hlt">type</span> <span class="hlt">model</span>, for the interaction between two species and their random natural environment is investigated. The effect of a random environment is <span class="hlt">modeled</span> as random pulse trains in the birth rate of the prey and the death rate of the predator. The generalized cell mapping method is applied to calculate the probability distributions of the species populations at a state of statistical quasistationarity. The time evolution of the population densities is studied, and the probability of the near extinction time, from an initial state to a critical state, is obtained. The effects on the ecosystem behaviors of the prey self-competition term and of the pulse mean arrival rate are also discussed. Our results indicate that the proposed pulse-<span class="hlt">type</span> <span class="hlt">model</span> shows obviously distinguishable characteristics from a Gaussian-<span class="hlt">type</span> <span class="hlt">model</span>, and may confer a significant advantage for <span class="hlt">modeling</span> the prey-predator system under discrete environmental fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018EPJP..133...16H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018EPJP..133...16H"><span>Solitons of shallow-water <span class="hlt">models</span> from energy-dependent spectral problems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haberlin, Jack; Lyons, Tony</p> <p>2018-01-01</p> <p>The current work investigates the soliton solutions of the Kaup-<span class="hlt">Boussinesq</span> equation using the inverse scattering transform method. We outline the construction of the Riemann-Hilbert problem for a pair of energy-dependent spectral problems for the system, which we then use to construct the solution of this hydrodynamic system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914688S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914688S"><span>Explicit <span class="hlt">modeling</span> of groundwater-surface water interactions using a simple bucket-<span class="hlt">type</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Staudinger, Maria; Carlier, Claire; Brunner, Philip; Seibert, Jan</p> <p>2017-04-01</p> <p>Longer dry spells can become critical for water supply and groundwater dependent ecosystems. During these dry spells groundwater is often the most relevant source for streams. Hence, the hydrological behavior of a catchment is often dominated by groundwater surface water interactions, which can vary considerably in space and time. While classical hydrological approaches hardly consider this spatial dependence, quantitative, hydrogeological <span class="hlt">modeling</span> approaches can couple surface runoff processes and groundwater processes. Hydrogeological <span class="hlt">modeling</span> can help to gain an improved understanding of catchment processes during low flow. However, due to their complex parametrization and large computational requirements, such hydrogeological <span class="hlt">models</span> are difficult to employ at catchment scale, particularly for a larger set of catchments. Then bucket-<span class="hlt">type</span> hydrological <span class="hlt">models</span> remain a practical alternative. In this study we combine the strengths of both the hydrogeological and bucket-<span class="hlt">type</span> hydrological <span class="hlt">models</span> to better understand low flow processes and ultimately to use this knowledge for low flow projections. Bucket-<span class="hlt">type</span> hydrological <span class="hlt">models</span> have traditionally not been developed with focus on the simulation of low flow. One consequence is that interactions between surface and groundwater are not explicitly considered. Water fluxes in bucket-<span class="hlt">type</span> hydrological <span class="hlt">models</span> are commonly simulated only in one direction, namely from the groundwater to the stream but not from the stream to the groundwater. This latter flux, however, can become more important during low flow situations. We therefore further developed the bucket-<span class="hlt">type</span> hydrological <span class="hlt">model</span> HBV to simulate low flow situations by allowing for exchange in both directions i.e. also from the stream to the groundwater. The additional HBV exchange box is developed by using a variety of synthetic hydrogeological <span class="hlt">models</span> as training set that were generated using a fully coupled, physically based hydrogeological <span class="hlt">model</span>. In this way processes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007NHESS...7..741D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007NHESS...7..741D"><span>Tsunami propagation <span class="hlt">modelling</span> - a sensitivity study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dao, M. H.; Tkalich, P.</p> <p>2007-12-01</p> <p>Indian Ocean (2004) Tsunami and following tragic consequences demonstrated lack of relevant experience and preparedness among involved coastal nations. After the event, scientific and forecasting circles of affected countries have started a capacity building to tackle similar problems in the future. Different approaches have been used for tsunami propagation, such as <span class="hlt">Boussinesq</span> and Nonlinear Shallow Water Equations (NSWE). These approximations were obtained assuming different relevant importance of nonlinear, dispersion and spatial gradient variation phenomena and terms. The paper describes further development of original TUNAMI-N2 <span class="hlt">model</span> to take into account additional phenomena: astronomic tide, sea bottom friction, dispersion, Coriolis force, and spherical curvature. The code is modified to be suitable for operational forecasting, and the resulting version (TUNAMI-N2-NUS) is verified using test cases, results of other <span class="hlt">models</span>, and real case scenarios. Using the 2004 Tsunami event as one of the scenarios, the paper examines sensitivity of numerical solutions to variation of different phenomena and parameters, and the results are analyzed and ranked accordingly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29543444','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29543444"><span>Generating Converged <span class="hlt">Accurate</span> Free Energy Surfaces for Chemical Reactions with a Force-Matched Semiempirical <span class="hlt">Model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kroonblawd, Matthew P; Pietrucci, Fabio; Saitta, Antonino Marco; Goldman, Nir</p> <p>2018-04-10</p> <p>We demonstrate the capability of creating robust density functional tight binding (DFTB) <span class="hlt">models</span> for chemical reactivity in prebiotic mixtures through force matching to short time scale quantum free energy estimates. Molecular dynamics using density functional theory (DFT) is a highly <span class="hlt">accurate</span> approach to generate free energy surfaces for chemical reactions, but the extreme computational cost often limits the time scales and range of thermodynamic states that can feasibly be studied. In contrast, DFTB is a semiempirical quantum method that affords up to a thousandfold reduction in cost and can recover DFT-level accuracy. Here, we show that a force-matched DFTB <span class="hlt">model</span> for aqueous glycine condensation reactions yields free energy surfaces that are consistent with experimental observations of reaction energetics. Convergence analysis reveals that multiple nanoseconds of combined trajectory are needed to reach a steady-fluctuating free energy estimate for glycine condensation. Predictive accuracy of force-matched DFTB is demonstrated by direct comparison to DFT, with the two approaches yielding surfaces with large regions that differ by only a few kcal mol -1 .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1438729-generating-converged-accurate-free-energy-surfaces-chemical-reactions-force-matched-semiempirical-model','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1438729-generating-converged-accurate-free-energy-surfaces-chemical-reactions-force-matched-semiempirical-model"><span>Generating Converged <span class="hlt">Accurate</span> Free Energy Surfaces for Chemical Reactions with a Force-Matched Semiempirical <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Kroonblawd, Matthew P.; Pietrucci, Fabio; Saitta, Antonino Marco; ...</p> <p>2018-03-15</p> <p>Here, we demonstrate the capability of creating robust density functional tight binding (DFTB) <span class="hlt">models</span> for chemical reactivity in prebiotic mixtures through force matching to short time scale quantum free energy estimates. Molecular dynamics using density functional theory (DFT) is a highly <span class="hlt">accurate</span> approach to generate free energy surfaces for chemical reactions, but the extreme computational cost often limits the time scales and range of thermodynamic states that can feasibly be studied. In contrast, DFTB is a semiempirical quantum method that affords up to a thousandfold reduction in cost and can recover DFT-level accuracy. Here, we show that a force-matched DFTBmore » <span class="hlt">model</span> for aqueous glycine condensation reactions yields free energy surfaces that are consistent with experimental observations of reaction energetics. Convergence analysis reveals that multiple nanoseconds of combined trajectory are needed to reach a steady-fluctuating free energy estimate for glycine condensation. Predictive accuracy of force-matched DFTB is demonstrated by direct comparison to DFT, with the two approaches yielding surfaces with large regions that differ by only a few kcal mol –1.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1438729-generating-converged-accurate-free-energy-surfaces-chemical-reactions-force-matched-semiempirical-model','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1438729-generating-converged-accurate-free-energy-surfaces-chemical-reactions-force-matched-semiempirical-model"><span>Generating Converged <span class="hlt">Accurate</span> Free Energy Surfaces for Chemical Reactions with a Force-Matched Semiempirical <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kroonblawd, Matthew P.; Pietrucci, Fabio; Saitta, Antonino Marco</p> <p></p> <p>Here, we demonstrate the capability of creating robust density functional tight binding (DFTB) <span class="hlt">models</span> for chemical reactivity in prebiotic mixtures through force matching to short time scale quantum free energy estimates. Molecular dynamics using density functional theory (DFT) is a highly <span class="hlt">accurate</span> approach to generate free energy surfaces for chemical reactions, but the extreme computational cost often limits the time scales and range of thermodynamic states that can feasibly be studied. In contrast, DFTB is a semiempirical quantum method that affords up to a thousandfold reduction in cost and can recover DFT-level accuracy. Here, we show that a force-matched DFTBmore » <span class="hlt">model</span> for aqueous glycine condensation reactions yields free energy surfaces that are consistent with experimental observations of reaction energetics. Convergence analysis reveals that multiple nanoseconds of combined trajectory are needed to reach a steady-fluctuating free energy estimate for glycine condensation. Predictive accuracy of force-matched DFTB is demonstrated by direct comparison to DFT, with the two approaches yielding surfaces with large regions that differ by only a few kcal mol –1.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17705688','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17705688"><span>Clinical validation of a new control-oriented <span class="hlt">model</span> of insulin and glucose dynamics in subjects with <span class="hlt">type</span> 1 diabetes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fabietti, Pier Giorgio; Canonico, Valentina; Orsini-Federici, Marco; Sarti, Eugenio; Massi-Benedetti, Massimo</p> <p>2007-08-01</p> <p>The development of an artificial pancreas requires an <span class="hlt">accurate</span> representation of diabetes pathophysiology to create effective and safe control systems for automatic insulin infusion regulation. The aim of the present study is the assessment of a previously developed mathematical <span class="hlt">model</span> of insulin and glucose metabolism in <span class="hlt">type</span> 1 diabetes and the evaluation of its effectiveness for the development and testing of control algorithms. Based on the already existing "minimal <span class="hlt">model</span>" a new mathematical <span class="hlt">model</span> was developed composed of glucose and insulin submodels. The glucose <span class="hlt">model</span> includes the representation of peripheral uptake, hepatic uptake and release, and renal clearance. The insulin <span class="hlt">model</span> describes the kinetics of exogenous insulin injected either subcutaneously or intravenously. The estimation of insulin sensitivity allows the <span class="hlt">model</span> to personalize parameters to each subject. Data sets from two different clinical trials were used here for <span class="hlt">model</span> validation through simulation studies. The first set had subcutaneous insulin injection, while the second set had intravenous insulin injection. The root mean square error between simulated and real blood glucose profiles (G(rms)) and the Clarke error grid analysis were used to evaluate the system efficacy. Results from our study demonstrated the <span class="hlt">model</span>'s capability in identifying individual characteristics even under different experimental conditions. This was reflected by an effective simulation as indicated by G(rms), and clinical acceptability by the Clarke error grid analysis, in both clinical data series. Simulation results confirmed the capacity of the <span class="hlt">model</span> to faithfully represent the glucose-insulin relationship in <span class="hlt">type</span> 1 diabetes in different circumstances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24375512','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24375512"><span><span class="hlt">Accurate</span> prediction of interfacial residues in two-domain proteins using evolutionary information: implications for three-dimensional <span class="hlt">modeling</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bhaskara, Ramachandra M; Padhi, Amrita; Srinivasan, Narayanaswamy</p> <p>2014-07-01</p> <p>With the preponderance of multidomain proteins in eukaryotic genomes, it is essential to recognize the constituent domains and their functions. Often function involves communications across the domain interfaces, and the knowledge of the interacting sites is essential to our understanding of the structure-function relationship. Using evolutionary information extracted from homologous domains in at least two diverse domain architectures (single and multidomain), we predict the interface residues corresponding to domains from the two-domain proteins. We also use information from the three-dimensional structures of individual domains of two-domain proteins to train naïve Bayes classifier <span class="hlt">model</span> to predict the interfacial residues. Our predictions are highly <span class="hlt">accurate</span> (∼85%) and specific (∼95%) to the domain-domain interfaces. This method is specific to multidomain proteins which contain domains in at least more than one protein architectural context. Using predicted residues to constrain domain-domain interaction, rigid-body docking was able to provide us with <span class="hlt">accurate</span> full-length protein structures with correct orientation of domains. We believe that these results can be of considerable interest toward rational protein and interaction design, apart from providing us with valuable information on the nature of interactions. © 2013 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5720514','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5720514"><span>Effects of early afterdepolarizations on excitation patterns in an <span class="hlt">accurate</span> <span class="hlt">model</span> of the human ventricles</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Seemann, Gunnar; Panfilov, Alexander V.; Vandersickel, Nele</p> <p>2017-01-01</p> <p>Early Afterdepolarizations, EADs, are defined as the reversal of the action potential before completion of the repolarization phase, which can result in ectopic beats. However, the series of mechanisms of EADs leading to these ectopic beats and related cardiac arrhythmias are not well understood. Therefore, we aimed to investigate the influence of this single cell behavior on the whole heart level. For this study we used a modified version of the Ten Tusscher-Panfilov <span class="hlt">model</span> of human ventricular cells (TP06) which we implemented in a 3D ventricle <span class="hlt">model</span> including realistic fiber orientations. To increase the likelihood of EAD formation at the single cell level, we reduced the repolarization reserve (RR) by reducing the rapid delayed rectifier Potassium current and raising the L-<span class="hlt">type</span> Calcium current. Varying these parameters defined a 2D parametric space where different excitation patterns could be classified. Depending on the initial conditions, by either exciting the ventricles with a spiral formation or burst pacing protocol, we found multiple different spatio-temporal excitation patterns. The spiral formation protocol resulted in the categorization of a stable spiral (S), a meandering spiral (MS), a spiral break-up regime (SB), spiral fibrillation <span class="hlt">type</span> B (B), spiral fibrillation <span class="hlt">type</span> A (A) and an oscillatory excitation <span class="hlt">type</span> (O). The last three patterns are a 3D generalization of previously found patterns in 2D. First, the spiral fibrillation <span class="hlt">type</span> B showed waves determined by a chaotic bi-excitable regime, i.e. mediated by both Sodium and Calcium waves at the same time and in same tissue settings. In the parameter region governed by the B pattern, single cells were able to repolarize completely and different (spiral) waves chaotically burst into each other without finishing a 360 degree rotation. Second, spiral fibrillation <span class="hlt">type</span> A patterns consisted of multiple small rotating spirals. Single cells failed to repolarize to the resting membrane potential hence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFDL25008Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFDL25008Z"><span>Numerical prediction of pollutant dispersion and transport in an atmospheric boundary layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zeoli, Stéphanie; Bricteux, Laurent; Mech. Eng. Dpt. Team</p> <p>2014-11-01</p> <p>The ability to <span class="hlt">accurately</span> predict concentration levels of air pollutant released from point sources is required in order to determine their environmental impact. A wall <span class="hlt">modeled</span> large-eddy simulation (WMLES) of the ABL is performed using the OpenFoam based solver SOWFA (Churchfield and Lee, NREL). It uses <span class="hlt">Boussinesq</span> approximation for buoyancy effects and takes into account Coriolis forces. A synthetic eddy method is proposed to properly <span class="hlt">model</span> turbulence inlet velocity boundary conditions. This method will be compared with the standard pressure gradient forcing. WMLES are usually performed using a standard Smagorinsky <span class="hlt">model</span> or its dynamic version. It is proposed here to investigate a subgrid scale (SGS) <span class="hlt">model</span> with a better spectral behavior. To this end, a regularized variational multiscale (RVMs) <span class="hlt">model</span> (Jeanmart and Winckelmans, 2007) is implemented together with standard wall function in order to preserve the dynamics of the large scales within the Ekman layer. The influence of the improved SGS <span class="hlt">model</span> on the wind simulation and scalar transport will be discussed based on turbulence diagnostics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24550740','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24550740"><span><span class="hlt">Accurate</span> and robust genomic prediction of celiac disease using statistical learning.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abraham, Gad; Tye-Din, Jason A; Bhalala, Oneil G; Kowalczyk, Adam; Zobel, Justin; Inouye, Michael</p> <p>2014-02-01</p> <p>Practical application of genomic-based risk stratification to clinical diagnosis is appealing yet performance varies widely depending on the disease and genomic risk score (GRS) method. Celiac disease (CD), a common immune-mediated illness, is strongly genetically determined and requires specific HLA haplotypes. HLA testing can exclude diagnosis but has low specificity, providing little information suitable for clinical risk stratification. Using six European cohorts, we provide a proof-of-concept that statistical learning approaches which simultaneously <span class="hlt">model</span> all SNPs can generate robust and highly <span class="hlt">accurate</span> predictive <span class="hlt">models</span> of CD based on genome-wide SNP profiles. The high predictive capacity replicated both in cross-validation within each cohort (AUC of 0.87-0.89) and in independent replication across cohorts (AUC of 0.86-0.9), despite differences in ethnicity. The <span class="hlt">models</span> explained 30-35% of disease variance and up to ∼43% of heritability. The GRS's utility was assessed in different clinically relevant settings. Comparable to HLA <span class="hlt">typing</span>, the GRS can be used to identify individuals without CD with ≥99.6% negative predictive value however, unlike HLA <span class="hlt">typing</span>, fine-scale stratification of individuals into categories of higher-risk for CD can identify those that would benefit from more invasive and costly definitive testing. The GRS is flexible and its performance can be adapted to the clinical situation by adjusting the threshold cut-off. Despite explaining a minority of disease heritability, our findings indicate a genomic risk score provides clinically relevant information to improve upon current diagnostic pathways for CD and support further studies evaluating the clinical utility of this approach in CD and other complex diseases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ISPAn.II1...23R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ISPAn.II1...23R"><span>Fixed-Wing Micro Aerial Vehicle for <span class="hlt">Accurate</span> Corridor Mapping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rehak, M.; Skaloud, J.</p> <p>2015-08-01</p> <p>In this study we present a Micro Aerial Vehicle (MAV) equipped with precise position and attitude sensors that together with a pre-calibrated camera enables <span class="hlt">accurate</span> corridor mapping. The design of the platform is based on widely available <span class="hlt">model</span> components to which we integrate an open-source autopilot, customized mass-market camera and navigation sensors. We adapt the concepts of system calibration from larger mapping platforms to MAV and evaluate them practically for their achievable accuracy. We present case studies for <span class="hlt">accurate</span> mapping without ground control points: first for a block configuration, later for a narrow corridor. We evaluate the mapping accuracy with respect to checkpoints and digital terrain <span class="hlt">model</span>. We show that while it is possible to achieve pixel (3-5 cm) mapping accuracy in both cases, precise aerial position control is sufficient for block configuration, the precise position and attitude control is required for corridor mapping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28729385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28729385"><span>pyQms enables universal and <span class="hlt">accurate</span> quantification of mass spectrometry data.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leufken, Johannes; Niehues, Anna; Sarin, L Peter; Wessel, Florian; Hippler, Michael; Leidel, Sebastian A; Fufezan, Christian</p> <p>2017-10-01</p> <p>Quantitative mass spectrometry (MS) is a key technique in many research areas (1), including proteomics, metabolomics, glycomics, and lipidomics. Because all of the corresponding molecules can be described by chemical formulas, universal quantification tools are highly desirable. Here, we present pyQms, an open-source software for <span class="hlt">accurate</span> quantification of all <span class="hlt">types</span> of molecules measurable by MS. pyQms uses isotope pattern matching that offers an <span class="hlt">accurate</span> quality assessment of all quantifications and the ability to directly incorporate mass spectrometer accuracy. pyQms is, due to its universal design, applicable to every research field, labeling strategy, and acquisition technique. This opens ultimate flexibility for researchers to design experiments employing innovative and hitherto unexplored labeling strategies. Importantly, pyQms performs very well to <span class="hlt">accurately</span> quantify partially labeled proteomes in large scale and high throughput, the most challenging task for a quantification algorithm. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.472.1432L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.472.1432L"><span>Local <span class="hlt">models</span> of astrophysical discs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Latter, Henrik N.; Papaloizou, John</p> <p>2017-12-01</p> <p>Local <span class="hlt">models</span> of gaseous accretion discs have been successfully employed for decades to describe an assortment of small-scale phenomena, from instabilities and turbulence, to dust dynamics and planet formation. For the most part, they have been derived in a physically motivated but essentially ad hoc fashion, with some of the mathematical assumptions never made explicit nor checked for consistency. This approach is susceptible to error, and it is easy to derive local <span class="hlt">models</span> that support spurious instabilities or fail to conserve key quantities. In this paper we present rigorous derivations, based on an asympototic ordering, and formulate a hierarchy of local <span class="hlt">models</span> (incompressible, <span class="hlt">Boussinesq</span> and compressible), making clear which is best suited for a particular flow or phenomenon, while spelling out explicitly the assumptions and approximations of each. We also discuss the merits of the anelastic approximation, emphasizing that anelastic systems struggle to conserve energy unless strong restrictions are imposed on the flow. The problems encountered by the anelastic approximation are exacerbated by the disc's differential rotation, but also attend non-rotating systems such as stellar interiors. We conclude with a defence of local <span class="hlt">models</span> and their continued utility in astrophysical research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4084796','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4084796"><span>SnowyOwl: <span class="hlt">accurate</span> prediction of fungal genes by using RNA-Seq and homology information to select among ab initio <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>Background Locating the protein-coding genes in novel genomes is essential to understanding and exploiting the genomic information but it is still difficult to <span class="hlt">accurately</span> predict all the genes. The recent availability of detailed information about transcript structure from high-throughput sequencing of messenger RNA (RNA-Seq) delineates many expressed genes and promises increased accuracy in gene prediction. Computational gene predictors have been intensively developed for and tested in well-studied animal genomes. Hundreds of fungal genomes are now or will soon be sequenced. The differences of fungal genomes from animal genomes and the phylogenetic sparsity of well-studied fungi call for gene-prediction tools tailored to them. Results SnowyOwl is a new gene prediction pipeline that uses RNA-Seq data to train and provide hints for the generation of Hidden Markov <span class="hlt">Model</span> (HMM)-based gene predictions and to evaluate the resulting <span class="hlt">models</span>. The pipeline has been developed and streamlined by comparing its predictions to manually curated gene <span class="hlt">models</span> in three fungal genomes and validated against the high-quality gene annotation of Neurospora crassa; SnowyOwl predicted N. crassa genes with 83% sensitivity and 65% specificity. SnowyOwl gains sensitivity by repeatedly running the HMM gene predictor Augustus with varied input parameters and selectivity by choosing the <span class="hlt">models</span> with best homology to known proteins and best agreement with the RNA-Seq data. Conclusions SnowyOwl efficiently uses RNA-Seq data to produce <span class="hlt">accurate</span> gene <span class="hlt">models</span> in both well-studied and novel fungal genomes. The source code for the SnowyOwl pipeline (in Python) and a web interface (in PHP) is freely available from http://sourceforge.net/projects/snowyowl/. PMID:24980894</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhDT.........1B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhDT.........1B"><span>Polarisation Spectral Synthesis For <span class="hlt">Type</span> Ia Supernova Explosion <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bulla, Mattia</p> <p>2017-02-01</p> <p>Despite their relevance across a broad range of astrophysical research topics, <span class="hlt">Type</span> Ia supernova explosions are still poorly understood and answers to the questions of when, why and how these events are triggered remain unclear. In this respect, polarisation offers a unique opportunity to discriminate between the variety of possible scenarios. The observational evidence that <span class="hlt">Type</span> Ia supernovae are associated with rather low polarisation signals (smaller than a few per cent) places strong constraints for <span class="hlt">models</span> and calls for modest asphericities in the progenitor system and/or explosion mechanism.The goal of this thesis is to assess the validity of contemporary <span class="hlt">Type</span> Ia supernova explosion <span class="hlt">models</span> by testing whether their predicted polarisation signatures can account for the small signals usually observed. To this end, we have implemented and tested an innovative Monte Carlo scheme in the radiative transfer code artis. Compared to previous Monte Carlo approaches, this technique produces synthetic observables (light curves, flux and polarisation spectra) with a substantial reduction in the Monte Carlo noise and therefore in the required computing time. This improvement is particularly crucial for our study as we aim to extract very weak polarisation signals, comparable to those detected in <span class="hlt">Type</span> Ia supernovae. We have also demonstrated the applicability of this method to other classes of supernovae via a preliminary study of the first spectropolarimetry observations of superluminous supernovae.Using this scheme, we have calculated synthetic spectropolarimetry for three multi-dimensional explosion <span class="hlt">models</span> recently proposed as promising candidates to explain <span class="hlt">Type</span> Ia supernovae. Our findings highlight the power of spectropolarimetry in testing and discriminating between different scenarios. While all the three <span class="hlt">models</span> predict light curves and flux spectra that are similar to each others and reproduce those observed in <span class="hlt">Type</span> Ia supernovae comparably well, polarisation does</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2242818','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2242818"><span><span class="hlt">Accurate</span> Structural Correlations from Maximum Likelihood Superpositions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Theobald, Douglas L; Wuttke, Deborah S</p> <p>2008-01-01</p> <p>The cores of globular proteins are densely packed, resulting in complicated networks of structural interactions. These interactions in turn give rise to dynamic structural correlations over a wide range of time scales. <span class="hlt">Accurate</span> analysis of these complex correlations is crucial for understanding biomolecular mechanisms and for relating structure to function. Here we report a highly <span class="hlt">accurate</span> technique for inferring the major modes of structural correlation in macromolecules using likelihood-based statistical analysis of sets of structures. This method is generally applicable to any ensemble of related molecules, including families of nuclear magnetic resonance (NMR) <span class="hlt">models</span>, different crystal forms of a protein, and structural alignments of homologous proteins, as well as molecular dynamics trajectories. Dominant modes of structural correlation are determined using principal components analysis (PCA) of the maximum likelihood estimate of the correlation matrix. The correlations we identify are inherently independent of the statistical uncertainty and dynamic heterogeneity associated with the structural coordinates. We additionally present an easily interpretable method (“PCA plots”) for displaying these positional correlations by color-coding them onto a macromolecular structure. Maximum likelihood PCA of structural superpositions, and the structural PCA plots that illustrate the results, will facilitate the <span class="hlt">accurate</span> determination of dynamic structural correlations analyzed in diverse fields of structural biology. PMID:18282091</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930039958&hterms=ia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dia','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930039958&hterms=ia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dia"><span>The cosmic gamma-ray background from <span class="hlt">Type</span> Ia supernovae</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>The, Lih-Sin; Leising, Mark D.; Clayton, Donald D.</p> <p>1993-01-01</p> <p>We present an improved calculation of the cumulative gamma-ray spectrum of <span class="hlt">Type</span> Ia supernovae during the history of the universe. We follow Clayton & Ward (1975) in using a few Friedmann <span class="hlt">models</span> and two simple histories of the average galaxian nucleosynthesis rate, but we improve their calculation by <span class="hlt">modeling</span> the gamma-ray scattering in detailed numerical <span class="hlt">models</span> of SN Ia's. The results confirm that near 1 MeV the SN Ia background may dominate, and that it is potentially observable, with high scientific importance. A very <span class="hlt">accurate</span> measurement of the cosmic background spectrum between 0.1 and 1.0 MeV may reveal the turn-on time and the evolution of the rate of <span class="hlt">Type</span> Ia supernova nucleosynthesis in the universe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JCoPh.364...73L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JCoPh.364...73L"><span>An <span class="hlt">accurate</span> front capturing scheme for tumor growth <span class="hlt">models</span> with a free boundary limit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Jian-Guo; Tang, Min; Wang, Li; Zhou, Zhennan</p> <p>2018-07-01</p> <p>We consider a class of tumor growth <span class="hlt">models</span> under the combined effects of density-dependent pressure and cell multiplication, with a free boundary <span class="hlt">model</span> as its singular limit when the pressure-density relationship becomes highly nonlinear. In particular, the constitutive law connecting pressure p and density ρ is p (ρ) = m/m-1 ρ m - 1, and when m ≫ 1, the cell density ρ may evolve its support according to a pressure-driven geometric motion with sharp interface along its boundary. The nonlinearity and degeneracy in the diffusion bring great challenges in numerical simulations. Prior to the present paper, there is lack of standard mechanism to numerically capture the front propagation speed as m ≫ 1. In this paper, we develop a numerical scheme based on a novel prediction-correction reformulation that can <span class="hlt">accurately</span> approximate the front propagation even when the nonlinearity is extremely strong. We show that the semi-discrete scheme naturally connects to the free boundary limit equation as m → ∞. With proper spatial discretization, the fully discrete scheme has improved stability, preserves positivity, and can be implemented without nonlinear solvers. Finally, extensive numerical examples in both one and two dimensions are provided to verify the claimed properties in various applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA602885','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA602885"><span>Studies of Stirring and Mixing at the Submesoscale in the Ocean: FY2013 Annual Report</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2013-09-30</p> <p>uhler, and R. Ferrari. Particle dispersion by random waves in the rotating <span class="hlt">Boussinesq</span> system . J. Fluid Mech., 670:150-175, 2011. Ferrari, R.. A...We have now run a suite of QG simulations in parallel with <span class="hlt">Boussinesq</span> Primitive Equation (PE) simulations (using the Diablo code), systematicaly...density fronts. J. Phys. Oceanogr., 40:1222-1242, 2010. Taylor, J., K. S. Smith and R. Ferrari. Submesoscale stirring of tracers in <span class="hlt">Boussinesq</span> and quasi</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010rdis.conf..407M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010rdis.conf..407M"><span>An Interval <span class="hlt">Type</span>-2 Fuzzy Multiple Echelon Supply Chain <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, Simon; John, Robert</p> <p></p> <p>Planning resources for a supply chain is a major factor determining its success or failure. In this paper we build on previous work introducing an Interval <span class="hlt">Type</span>-2 Fuzzy Logic <span class="hlt">model</span> of a multiple echelon supply chain. It is believed that the additional degree of uncertainty provided by Interval <span class="hlt">Type</span>-2 Fuzzy Logic will allow for better representation of the uncertainty and vagueness present in resource planning <span class="hlt">models</span>. First, the subject of Supply Chain Management is introduced, then some background is given on related work using <span class="hlt">Type</span>-1 Fuzzy Logic. A description of the Interval <span class="hlt">Type</span>-2 Fuzzy <span class="hlt">model</span> is given, and a test scenario detailed. A Genetic Algorithm uses the <span class="hlt">model</span> to search for a near-optimal plan for the scenario. A discussion of the results follows, along with conclusions and details of intended further work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3435997','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3435997"><span>An <span class="hlt">Accurately</span> Controlled Antagonistic Shape Memory Alloy Actuator with Self-Sensing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Tian-Miao; Shi, Zhen-Yun; Liu, Da; Ma, Chen; Zhang, Zhen-Hua</p> <p>2012-01-01</p> <p>With the progress of miniaturization, shape memory alloy (SMA) actuators exhibit high energy density, self-sensing ability and ease of fabrication, which make them well suited for practical applications. This paper presents a self-sensing controlled actuator drive that was designed using antagonistic pairs of SMA wires. Under a certain pre-strain and duty cycle, the stress between two wires becomes constant. Meanwhile, the strain to resistance curve can minimize the hysteresis gap between the heating and the cooling paths. The curves of both wires are then <span class="hlt">modeled</span> by fitting polynomials such that the measured resistance can be used directly to determine the difference between the testing values and the target strain. The hysteresis <span class="hlt">model</span> of strains to duty cycle difference has been used as compensation. <span class="hlt">Accurate</span> control is demonstrated through step response and sinusoidal tracking. The experimental results show that, under a combination control program, the root-mean-square error can be reduced to 1.093%. The limited bandwidth of the frequency is estimated to be 0.15 Hz. Two sets of instruments with three degrees of freedom are illustrated to show how this <span class="hlt">type</span> actuator could be potentially implemented. PMID:22969368</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol6/pdf/CFR-2010-title46-vol6-sec160-060-2.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol6/pdf/CFR-2010-title46-vol6-sec160-060-2.pdf"><span>46 CFR 160.060-2 - <span class="hlt">Type</span> and <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS..., Adult and Child § 160.060-2 <span class="hlt">Type</span> and <span class="hlt">model</span>. Each buoyant vest specified in this subpart is a: (a) Standard: (1) <span class="hlt">Model</span> AY, adult (for persons weighing over 90 pounds); or (2) <span class="hlt">Model</span> CYM, child, medium (for...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29743009','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29743009"><span>Muver, a computational framework for <span class="hlt">accurately</span> calling accumulated mutations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burkholder, Adam B; Lujan, Scott A; Lavender, Christopher A; Grimm, Sara A; Kunkel, Thomas A; Fargo, David C</p> <p>2018-05-09</p> <p>Identification of mutations from next-generation sequencing data typically requires a balance between sensitivity and accuracy. This is particularly true of DNA insertions and deletions (indels), that can impart significant phenotypic consequences on cells but are harder to call than substitution mutations from whole genome mutation accumulation experiments. To overcome these difficulties, we present muver, a computational framework that integrates established bioinformatics tools with novel analytical methods to generate mutation calls with the extremely low false positive rates and high sensitivity required for <span class="hlt">accurate</span> mutation rate determination and comparison. Muver uses statistical comparison of ancestral and descendant allelic frequencies to identify variant loci and assigns genotypes with <span class="hlt">models</span> that include per-sample assessments of sequencing errors by mutation <span class="hlt">type</span> and repeat context. Muver identifies maximally parsimonious mutation pathways that connect these genotypes, differentiating potential allelic conversion events and delineating ambiguities in mutation location, <span class="hlt">type</span>, and size. Benchmarking with a human gold standard father-son pair demonstrates muver's sensitivity and low false positive rates. In DNA mismatch repair (MMR) deficient Saccharomyces cerevisiae, muver detects multi-base deletions in homopolymers longer than the replicative polymerase footprint at rates greater than predicted for sequential single-base deletions, implying a novel multi-repeat-unit slippage mechanism. Benchmarking results demonstrate the high accuracy and sensitivity achieved with muver, particularly for indels, relative to available tools. Applied to an MMR-deficient Saccharomyces cerevisiae system, muver mutation calls facilitate mechanistic insights into DNA replication fidelity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA622135','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA622135"><span><span class="hlt">Boussinesq</span> <span class="hlt">Modeling</span> for Inlets, Harbors & Structures (Bouss-2D)</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2014-10-27</p> <p>subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 27...work applications. It may be used from deep to shallow water to simulate the nonlinear wave processes of interest in the open coast, nearshore zone...design, and operation of coastal navigation and flooding projects. It provides key engineering estimates for coastal and hydraulic engineering practice</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23472156','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23472156"><span>Methods for applying <span class="hlt">accurate</span> digital PCR analysis on low copy DNA samples.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Whale, Alexandra S; Cowen, Simon; Foy, Carole A; Huggett, Jim F</p> <p>2013-01-01</p> <p>Digital PCR (dPCR) is a highly <span class="hlt">accurate</span> molecular approach, capable of precise measurements, offering a number of unique opportunities. However, in its current format dPCR can be limited by the amount of sample that can be analysed and consequently additional considerations such as performing multiplex reactions or pre-amplification can be considered. This study investigated the impact of duplexing and pre-amplification on dPCR analysis by using three different assays targeting a <span class="hlt">model</span> template (a portion of the Arabidopsis thaliana alcohol dehydrogenase gene). We also investigated the impact of different template <span class="hlt">types</span> (linearised plasmid clone and more complex genomic DNA) on measurement precision using dPCR. We were able to demonstrate that duplex dPCR can provide a more precise measurement than uniplex dPCR, while applying pre-amplification or varying template <span class="hlt">type</span> can significantly decrease the precision of dPCR. Furthermore, we also demonstrate that the pre-amplification step can introduce measurement bias that is not consistent between experiments for a sample or assay and so could not be compensated for during the analysis of this data set. We also describe a <span class="hlt">model</span> for estimating the prevalence of molecular dropout and identify this as a source of dPCR imprecision. Our data have demonstrated that the precision afforded by dPCR at low sample concentration can exceed that of the same template post pre-amplification thereby negating the need for this additional step. Our findings also highlight the technical differences between different templates <span class="hlt">types</span> containing the same sequence that must be considered if plasmid DNA is to be used to assess or control for more complex templates like genomic DNA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3589384','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3589384"><span>Methods for Applying <span class="hlt">Accurate</span> Digital PCR Analysis on Low Copy DNA Samples</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Whale, Alexandra S.; Cowen, Simon; Foy, Carole A.; Huggett, Jim F.</p> <p>2013-01-01</p> <p>Digital PCR (dPCR) is a highly <span class="hlt">accurate</span> molecular approach, capable of precise measurements, offering a number of unique opportunities. However, in its current format dPCR can be limited by the amount of sample that can be analysed and consequently additional considerations such as performing multiplex reactions or pre-amplification can be considered. This study investigated the impact of duplexing and pre-amplification on dPCR analysis by using three different assays targeting a <span class="hlt">model</span> template (a portion of the Arabidopsis thaliana alcohol dehydrogenase gene). We also investigated the impact of different template <span class="hlt">types</span> (linearised plasmid clone and more complex genomic DNA) on measurement precision using dPCR. We were able to demonstrate that duplex dPCR can provide a more precise measurement than uniplex dPCR, while applying pre-amplification or varying template <span class="hlt">type</span> can significantly decrease the precision of dPCR. Furthermore, we also demonstrate that the pre-amplification step can introduce measurement bias that is not consistent between experiments for a sample or assay and so could not be compensated for during the analysis of this data set. We also describe a <span class="hlt">model</span> for estimating the prevalence of molecular dropout and identify this as a source of dPCR imprecision. Our data have demonstrated that the precision afforded by dPCR at low sample concentration can exceed that of the same template post pre-amplification thereby negating the need for this additional step. Our findings also highlight the technical differences between different templates <span class="hlt">types</span> containing the same sequence that must be considered if plasmid DNA is to be used to assess or control for more complex templates like genomic DNA. PMID:23472156</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14705200','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14705200"><span>Highly <span class="hlt">accurate</span> nephelometric titrimetry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhan, Xiancheng; Li, Chengrong; Li, Zhiyi; Yang, Xiucen; Zhong, Shuguang; Yi, Tao</p> <p>2004-02-01</p> <p>A method that <span class="hlt">accurately</span> indicates the end-point of precipitation reactions by the measurement of the relative intensity of the scattered light in the titrate is presented. A new nephelometric titrator with an internal nephelometric sensor has been devised. The work of the titrator including the sensor and change in the turbidity of the titrate and intensity of the scattered light are described. The accuracy of the nephelometric titrimetry is discussed theoretically. The titration of NaCl with AgNO(3) serves as a <span class="hlt">model</span>. A relative error as well as deviation is within 0.2% under the experimental conditions. The applicability of the titrimetry in pharmaceutical analyses, for example, phenytoin sodium and procaine hydrochloride, is generally illustrated. Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA218029','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA218029"><span>The Effects of Psychological <span class="hlt">Type</span> and Information Presentation on Decision Making</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1989-12-01</p> <p>States Air Force for giving me the opportunity to attend AFIT and learn more about information systems, management, and myself. I hope to provide a...19 The Orientation Dichotomy: Extravert/ Introvert ...................... 21 The Perception Dichotomy: Sensing vs. Intuition.................... 22...Specifically, Introverts were more <span class="hlt">accurate</span> than Extraverts, Sensing <span class="hlt">types</span> were more <span class="hlt">accurate</span> than Intuitive <span class="hlt">types</span>, Thinking <span class="hlt">types</span> were more <span class="hlt">accurate</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28559099','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28559099"><span>Forecasting <span class="hlt">model</span> for Pea seed-borne mosaic virus epidemics in field pea crops in a Mediterranean-<span class="hlt">type</span> environment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Congdon, B S; Coutts, B A; Jones, R A C; Renton, M</p> <p>2017-09-15</p> <p>An empirical <span class="hlt">model</span> was developed to forecast Pea seed-borne mosaic virus (PSbMV) incidence at a critical phase of the annual growing season to predict yield loss in field pea crops sown under Mediterranean-<span class="hlt">type</span> conditions. The <span class="hlt">model</span> uses pre-growing season rainfall to calculate an index of aphid abundance in early-August which, in combination with PSbMV infection level in seed sown, is used to forecast virus crop incidence. Using predicted PSbMV crop incidence in early-August and day of sowing, PSbMV transmission from harvested seed was also predicted, albeit less <span class="hlt">accurately</span>. The <span class="hlt">model</span> was developed so it provides forecasts before sowing to allow sufficient time to implement control recommendations, such as having representative seed samples tested for PSbMV transmission rate to seedlings, obtaining seed with minimal PSbMV infection or of a PSbMV-resistant cultivar, and implementation of cultural management strategies. The <span class="hlt">model</span> provides a disease forecast risk indication, taking into account predicted percentage yield loss to PSbMV infection and economic factors involved in field pea production. This disease risk forecast delivers location-specific recommendations regarding PSbMV management to end-users. These recommendations will be delivered directly to end-users via SMS alerts with links to web support that provide information on PSbMV management options. This <span class="hlt">modelling</span> and decision support system approach would likely be suitable for use in other world regions where field pea is grown in similar Mediterranean-<span class="hlt">type</span> environments. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25058737','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25058737"><span><span class="hlt">Accurate</span> and self-consistent procedure for determining pH in seawater desalination brines and its manifestation in reverse osmosis <span class="hlt">modeling</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nir, Oded; Marvin, Esra; Lahav, Ori</p> <p>2014-11-01</p> <p>Measuring and <span class="hlt">modeling</span> pH in concentrated aqueous solutions in an <span class="hlt">accurate</span> and consistent manner is of paramount importance to many R&D and industrial applications, including RO desalination. Nevertheless, unified definitions and standard procedures have yet to be developed for solutions with ionic strength higher than ∼0.7 M, while implementation of conventional pH determination approaches may lead to significant errors. In this work a systematic yet simple methodology for measuring pH in concentrated solutions (dominated by Na(+)/Cl(-)) was developed and evaluated, with the aim of achieving consistency with the Pitzer ion-interaction approach. Results indicate that the addition of 0.75 M of NaCl to NIST buffers, followed by assigning a new standard pH (calculated based on the Pitzer approach), enabled reducing measured errors to below 0.03 pH units in seawater RO brines (ionic strength up to 2 M). To facilitate its use, the method was developed to be both conceptually and practically analogous to the conventional pH measurement procedure. The method was used to measure the pH of seawater RO retentates obtained at varying recovery ratios. The results matched better the pH values predicted by an <span class="hlt">accurate</span> RO transport <span class="hlt">model</span>. Calibrating the <span class="hlt">model</span> by the measured pH values enabled better boron transport prediction. A Donnan-induced phenomenon, affecting pH in both retentate and permeate streams, was identified and quantified. Copyright © 2014 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007IJMPA..22.1983A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007IJMPA..22.1983A"><span>Uniqueness of Petrov <span class="hlt">Type</span> D Spatially Inhomogeneous Irrotational Silent <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Apostolopoulos, Pantelis S.; Carot, Jaume</p> <p></p> <p>The consistency of the constraint with the evolution equations for spatially inhomogeneous and irrotational silent (SIIS) <span class="hlt">models</span> of Petrov <span class="hlt">type</span> I, demands that the former are preserved along the timelike congruence represented by the velocity of the dust fluid, leading to new nontrivial constraints. This fact has been used to conjecture that the resulting <span class="hlt">models</span> correspond to the spatially homogeneous (SH) <span class="hlt">models</span> of Bianchi <span class="hlt">type</span> I, at least for the case where the cosmological constant vanish. By exploiting the full set of the constraint equations as expressed in the 1+3 covariant formalism and using elements from the theory of the spacelike congruences, we provide a direct and simple proof of this conjecture for vacuum and dust fluid <span class="hlt">models</span>, which shows that the Szekeres family of solutions represents the most general class of SIIS <span class="hlt">models</span>. The suggested procedure also shows that, the uniqueness of the SIIS of the Petrov <span class="hlt">type</span> D is not, in general, affected by the presence of a nonzero pressure fluid. Therefore, in order to allow a broader class of Petrov <span class="hlt">type</span> I solutions apart from the SH <span class="hlt">models</span> of Bianchi <span class="hlt">type</span> I, one should consider more general "silent" configurations by relaxing the vanishing of the vorticity and the magnetic part of the Weyl tensor but maintaining their "silence" properties, i.e. the vanishing of the curls of Eab, Hab and the pressure p.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005CQGra..22..579C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005CQGra..22..579C"><span>A dynamical systems approach to the tilted Bianchi <span class="hlt">models</span> of solvable <span class="hlt">type</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coley, Alan; Hervik, Sigbjørn</p> <p>2005-02-01</p> <p>We use a dynamical systems approach to analyse the tilting spatially homogeneous Bianchi <span class="hlt">models</span> of solvable <span class="hlt">type</span> (e.g., <span class="hlt">types</span> VIh and VIIh) with a perfect fluid and a linear barotropic γ-law equation of state. In particular, we study the late-time behaviour of tilted Bianchi <span class="hlt">models</span>, with an emphasis on the existence of equilibrium points and their stability properties. We briefly discuss the tilting Bianchi <span class="hlt">type</span> V <span class="hlt">models</span> and the late-time asymptotic behaviour of irrotational Bianchi <span class="hlt">type</span> VII0 <span class="hlt">models</span>. We prove the important result that for non-inflationary Bianchi <span class="hlt">type</span> VIIh <span class="hlt">models</span> vacuum plane-wave solutions are the only future attracting equilibrium points in the Bianchi <span class="hlt">type</span> VIIh invariant set. We then investigate the dynamics close to the plane-wave solutions in more detail, and discover some new features that arise in the dynamical behaviour of Bianchi cosmologies with the inclusion of tilt. We point out that in a tiny open set of parameter space in the <span class="hlt">type</span> IV <span class="hlt">model</span> (the loophole) there exist closed curves which act as attracting limit cycles. More interestingly, in the Bianchi <span class="hlt">type</span> VIIh <span class="hlt">models</span> there is a bifurcation in which a set of equilibrium points turns into closed orbits. There is a region in which both sets of closed curves coexist, and it appears that for the <span class="hlt">type</span> VIIh <span class="hlt">models</span> in this region the solution curves approach a compact surface which is topologically a torus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OcMod.116....1E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OcMod.116....1E"><span>High-order <span class="hlt">accurate</span> finite-volume formulations for the pressure gradient force in layered ocean <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engwirda, Darren; Kelley, Maxwell; Marshall, John</p> <p>2017-08-01</p> <p>Discretisation of the horizontal pressure gradient force in layered ocean <span class="hlt">models</span> is a challenging task, with non-trivial interactions between the thermodynamics of the fluid and the geometry of the layers often leading to numerical difficulties. We present two new finite-volume schemes for the pressure gradient operator designed to address these issues. In each case, the horizontal acceleration is computed as an integration of the contact pressure force that acts along the perimeter of an associated momentum control-volume. A pair of new schemes are developed by exploring different control-volume geometries. Non-linearities in the underlying equation-of-state definitions and thermodynamic profiles are treated using a high-order <span class="hlt">accurate</span> numerical integration framework, designed to preserve hydrostatic balance in a non-linear manner. Numerical experiments show that the new methods achieve high levels of consistency, maintaining hydrostatic and thermobaric equilibrium in the presence of strongly-sloping layer geometries, non-linear equations-of-state and non-uniform vertical stratification profiles. These results suggest that the new pressure gradient formulations may be appropriate for general circulation <span class="hlt">models</span> that employ hybrid vertical coordinates and/or terrain-following representations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29054464','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29054464"><span>Improved kinetic <span class="hlt">model</span> of Escherichia coli central carbon metabolism in batch and continuous cultures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kurata, Hiroyuki; Sugimoto, Yurie</p> <p>2018-02-01</p> <p>Many kinetic <span class="hlt">models</span> of Escherichia coli central metabolism have been built, but few <span class="hlt">models</span> <span class="hlt">accurately</span> reproduced the dynamic behaviors of wild <span class="hlt">type</span> and multiple genetic mutants. In 2016, our latest kinetic <span class="hlt">model</span> improved problems of existing <span class="hlt">models</span> to reproduce the cell growth and glucose uptake of wild <span class="hlt">type</span>, ΔpykA:pykF and Δpgi in a batch culture, while it overestimated the glucose uptake and cell growth rates of Δppc and hardly captured the typical characteristics of the glyoxylate and TCA cycle fluxes for Δpgi and Δppc. Such discrepancies between the simulated and experimental data suggested biological complexity. In this study, we overcame these problems by assuming critical mechanisms regarding the OAA-regulated isocitrate dehydrogenase activity, aceBAK gene regulation and growth suppression. The present <span class="hlt">model</span> <span class="hlt">accurately</span> predicts the extracellular and intracellular dynamics of wild <span class="hlt">type</span> and many gene knockout mutants in batch and continuous cultures. It is now the most <span class="hlt">accurate</span>, detailed kinetic <span class="hlt">model</span> of E. coli central carbon metabolism and will contribute to advances in mathematical <span class="hlt">modeling</span> of cell factories. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6061O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6061O"><span>Interplanetary density <span class="hlt">models</span> as inferred from solar <span class="hlt">Type</span> III bursts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oppeneiger, Lucas; Boudjada, Mohammed Y.; Lammer, Helmut; Lichtenegger, Herbert</p> <p>2016-04-01</p> <p>We report on the density <span class="hlt">models</span> derived from spectral features of solar <span class="hlt">Type</span> III bursts. They are generated by beams of electrons travelling outward from the Sun along open magnetic field lines. Electrons generate Langmuir waves at the plasma frequency along their ray paths through the corona and the interplanetary medium. A large frequency band is covered by the <span class="hlt">Type</span> III bursts from several MHz down to few kHz. In this analysis, we consider the previous empirical density <span class="hlt">models</span> proposed to describe the electron density in the interplanetary medium. We show that those <span class="hlt">models</span> are mainly based on the analysis of <span class="hlt">Type</span> III bursts generated in the interplanetary medium and observed by satellites (e.g. RAE, HELIOS, VOYAGER, ULYSSES,WIND). Those <span class="hlt">models</span> are confronted to stereoscopic observations of <span class="hlt">Type</span> III bursts recorded by WIND, ULYSSES and CASSINI spacecraft. We discuss the spatial evolution of the electron beam along the interplanetary medium where the trajectory is an Archimedean spiral. We show that the electron beams and the source locations are depending on the choose of the empirical density <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA270615','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA270615"><span>A Quantitative <span class="hlt">Model</span> of Expert Transcription <span class="hlt">Typing</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1993-03-08</p> <p>side of pure psychology, several researchers have argued that transcription <span class="hlt">typing</span> is a particularly good activity for the study of human skilled...phenomenon with a quantitative METT prediction. The first, quick and dirty analysis gives a good prediction of the copy span, in fact, it is even...<span class="hlt">typing</span>, it should be demonstrated that the mechanism of the <span class="hlt">model</span> does not get in the way of good predictions. If situations occur where the entire</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1438754','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1438754"><span>High Order <span class="hlt">Accurate</span> Finite Difference <span class="hlt">Modeling</span> of Seismo-Acoustic Wave Propagation in a Moving Atmosphere and a Heterogeneous Earth <span class="hlt">Model</span> Coupled Across a Realistic Topography</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Petersson, N. Anders; Sjogreen, Bjorn</p> <p></p> <p>Here, we develop a numerical method for simultaneously simulating acoustic waves in a realistic moving atmosphere and seismic waves in a heterogeneous earth <span class="hlt">model</span>, where the motions are coupled across a realistic topography. We <span class="hlt">model</span> acoustic wave propagation by solving the linearized Euler equations of compressible fluid mechanics. The seismic waves are <span class="hlt">modeled</span> by the elastic wave equation in a heterogeneous anisotropic material. The motion is coupled by imposing continuity of normal velocity and normal stresses across the topographic interface. Realistic topography is resolved on a curvilinear grid that follows the interface. The governing equations are discretized using high ordermore » <span class="hlt">accurate</span> finite difference methods that satisfy the principle of summation by parts. We apply the energy method to derive the discrete interface conditions and to show that the coupled discretization is stable. The implementation is verified by numerical experiments, and we demonstrate a simulation of coupled wave propagation in a windy atmosphere and a realistic earth <span class="hlt">model</span> with non-planar topography.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1438754-high-order-accurate-finite-difference-modeling-seismo-acoustic-wave-propagation-moving-atmosphere-heterogeneous-earth-model-coupled-across-realistic-topography','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1438754-high-order-accurate-finite-difference-modeling-seismo-acoustic-wave-propagation-moving-atmosphere-heterogeneous-earth-model-coupled-across-realistic-topography"><span>High Order <span class="hlt">Accurate</span> Finite Difference <span class="hlt">Modeling</span> of Seismo-Acoustic Wave Propagation in a Moving Atmosphere and a Heterogeneous Earth <span class="hlt">Model</span> Coupled Across a Realistic Topography</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Petersson, N. Anders; Sjogreen, Bjorn</p> <p>2017-04-18</p> <p>Here, we develop a numerical method for simultaneously simulating acoustic waves in a realistic moving atmosphere and seismic waves in a heterogeneous earth <span class="hlt">model</span>, where the motions are coupled across a realistic topography. We <span class="hlt">model</span> acoustic wave propagation by solving the linearized Euler equations of compressible fluid mechanics. The seismic waves are <span class="hlt">modeled</span> by the elastic wave equation in a heterogeneous anisotropic material. The motion is coupled by imposing continuity of normal velocity and normal stresses across the topographic interface. Realistic topography is resolved on a curvilinear grid that follows the interface. The governing equations are discretized using high ordermore » <span class="hlt">accurate</span> finite difference methods that satisfy the principle of summation by parts. We apply the energy method to derive the discrete interface conditions and to show that the coupled discretization is stable. The implementation is verified by numerical experiments, and we demonstrate a simulation of coupled wave propagation in a windy atmosphere and a realistic earth <span class="hlt">model</span> with non-planar topography.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4559855','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4559855"><span>Seeing and Being Seen: Predictors of <span class="hlt">Accurate</span> Perceptions about Classmates’ Relationships</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Neal, Jennifer Watling; Neal, Zachary P.; Cappella, Elise</p> <p>2015-01-01</p> <p>This study examines predictors of observer accuracy (i.e. seeing) and target accuracy (i.e. being seen) in perceptions of classmates’ relationships in a predominantly African American sample of 420 second through fourth graders (ages 7 – 11). Girls, children in higher grades, and children in smaller classrooms were more <span class="hlt">accurate</span> observers. Targets (i.e. pairs of children) were more <span class="hlt">accurately</span> observed when they occurred in smaller classrooms of higher grades and involved same-sex, high-popularity, and similar-popularity children. Moreover, relationships between pairs of girls were more <span class="hlt">accurately</span> observed than relationships between pairs of boys. As a set, these findings suggest the importance of both observer and target characteristics for children’s <span class="hlt">accurate</span> perceptions of classroom relationships. Moreover, the substantial variation in observer accuracy and target accuracy has methodological implications for both peer-reported assessments of classroom relationships and the use of stochastic actor-based <span class="hlt">models</span> to understand peer selection and socialization processes. PMID:26347582</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.C53F..05P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.C53F..05P"><span><span class="hlt">Accurate</span> numerical forward <span class="hlt">model</span> for optimal retracking of SIRAL2 SAR echoes over open ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Phalippou, L.; Demeestere, F.</p> <p>2011-12-01</p> <p>The SAR mode of SIRAL-2 on board Cryosat-2 has been designed to measure primarily sea-ice and continental ice (Wingham et al. 2005). In 2005, K. Raney (KR, 2005) pointed out the improvements brought by SAR altimeter for open ocean. KR results were mostly based on 'rule of thumb' considerations on speckle noise reduction due to the higher PRF and to speckle decorrelation after SAR processing. In 2007, Phalippou and Enjolras (PE,2007) provided the theoretical background for optimal retracking of SAR echoes over ocean with a focus on the forward <span class="hlt">modelling</span> of the power-waveforms. The accuracies of geophysical parameters (range, significant wave heights, and backscattering coefficient) retrieved from SAR altimeter data were derived accounting for SAR echo shape and speckle noise <span class="hlt">accurate</span> <span class="hlt">modelling</span>. The step forward to optimal retracking using numerical forward <span class="hlt">model</span> (NFM) was also pointed out. NFM of the power waveform avoids analytical approximation, a warranty to minimise the geophysical dependent biases in the retrieval. NFM have been used for many years, in operational meteorology in particular, for retrieving temperature and humidity profiles from IR and microwave radiometers as the radiative transfer function is complex (Eyre, 1989). So far this technique was not used in the field of ocean conventional altimetry as analytical <span class="hlt">models</span> (e.g. Brown's <span class="hlt">model</span> for instance) were found to give sufficient accuracy. However, although NFM seems desirable even for conventional nadir altimetry, it becomes inevitable if one wish to process SAR altimeter data as the transfer function is too complex to be approximated by a simple analytical function. This was clearly demonstrated in PE 2007. The paper describes the background to SAR data retracking over open ocean. Since PE 2007 improvements have been brought to the forward <span class="hlt">model</span> and it is shown that the altimeter on-ground and in flight characterisation (e.g antenna pattern range impulse response, azimuth impulse response</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.1270B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.1270B"><span><span class="hlt">Model</span> reduction of the numerical analysis of Low Impact Developments techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brunetti, Giuseppe; Šimůnek, Jirka; Wöhling, Thomas; Piro, Patrizia</p> <p>2017-04-01</p> <p>Mechanistic <span class="hlt">models</span> have proven to be <span class="hlt">accurate</span> and reliable tools for the numerical analysis of the hydrological behavior of Low Impact Development (LIDs) techniques. However, their widespread adoption is limited by their complexity and computational cost. Recent studies have tried to address this issue by investigating the application of new techniques, such as surrogate-based <span class="hlt">modeling</span>. However, current results are still limited and fragmented. One of such approaches, the <span class="hlt">Model</span> Order Reduction (MOR) technique, can represent a valuable tool for reducing the computational complexity of a numerical problems by computing an approximation of the original <span class="hlt">model</span>. While this technique has been extensively used in water-related problems, no studies have evaluated its use in LIDs <span class="hlt">modeling</span>. Thus, the main aim of this study is to apply the MOR technique for the development of a reduced order <span class="hlt">model</span> (ROM) for the numerical analysis of the hydrologic behavior of LIDs, in particular green roofs. The <span class="hlt">model</span> should be able to correctly reproduce all the hydrological processes of a green roof while reducing the computational cost. The proposed <span class="hlt">model</span> decouples the subsurface water dynamic of a green roof in a) one-dimensional (1D) vertical flow through a green roof itself and b) one-dimensional saturated lateral flow along the impervious rooftop. The green roof is horizontally discretized in N elements. Each element represents a vertical domain, which can have different properties or boundary conditions. The 1D Richards equation is used to simulate flow in the substrate and drainage layers. Simulated outflow from the vertical domain is used as a recharge term for saturated lateral flow, which is described using the kinematic wave approximation of the <span class="hlt">Boussinesq</span> equation. The proposed <span class="hlt">model</span> has been compared with the mechanistic <span class="hlt">model</span> HYDRUS-2D, which numerically solves the Richards equation for the whole domain. The HYDRUS-1D code has been used for the description of vertical flow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ApJ...654L.123W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ApJ...654L.123W"><span>A <span class="hlt">Model</span>-independent Photometric Redshift Estimator for <span class="hlt">Type</span> Ia Supernovae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yun</p> <p>2007-01-01</p> <p>The use of <span class="hlt">Type</span> Ia supernovae (SNe Ia) as cosmological standard candles is fundamental in modern observational cosmology. In this Letter, we derive a simple empirical photometric redshift estimator for SNe Ia using a training set of SNe Ia with multiband (griz) light curves and spectroscopic redshifts obtained by the Supernova Legacy Survey (SNLS). This estimator is analytical and <span class="hlt">model</span>-independent it does not use spectral templates. We use all the available SNe Ia from SNLS with near-maximum photometry in griz (a total of 40 SNe Ia) to train and test our photometric redshift estimator. The difference between the estimated redshifts zphot and the spectroscopic redshifts zspec, (zphot-zspec)/(1+zspec), has rms dispersions of 0.031 for 20 SNe Ia used in the training set, and 0.050 for 20 SNe Ia not used in the training set. The dispersion is of the same order of magnitude as the flux uncertainties at peak brightness for the SNe Ia. There are no outliers. This photometric redshift estimator should significantly enhance the ability of observers to <span class="hlt">accurately</span> target high-redshift SNe Ia for spectroscopy in ongoing surveys. It will also dramatically boost the cosmological impact of very large future supernova surveys, such as those planned for the Advanced Liquid-mirror Probe for Astrophysics, Cosmology, and Asteroids (ALPACA) and the Large Synoptic Survey Telescope (LSST).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT.......328S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT.......328S"><span>A time <span class="hlt">accurate</span> prediction of the viscous flow in a turbine stage including a rotor in motion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shavalikul, Akamol</p> <p></p> <p> in the relative frame of reference; the boundary conditions for the computations were obtained from inlet flow measurements performed in the AFTRF. A complete turbine stage, including an NGV and a rotor row was simulated using the RANS solver with the SST kappa -- o turbulence <span class="hlt">model</span>, with two different computational <span class="hlt">models</span> for the interface between the rotating component and the stationary component. The first interface <span class="hlt">model</span>, the circumferentially averaged mixing plane <span class="hlt">model</span>, was solved for a fixed position of the rotor blades relative to the NGV in the stationary frame of reference. The information transferred between the NGV and rotor domains is obtained by averaging across the entire interface. The quasi-steady state flow characteristics of the AFTRF can be obtained from this interface <span class="hlt">model</span>. After the <span class="hlt">model</span> was validated with the existing experimental data, this <span class="hlt">model</span> was not only used to investigate the flow characteristics in the turbine stage but also the effects of using pressure side rotor tip extensions. The tip leakage flow fields simulated from this <span class="hlt">model</span> and from the linear cascade <span class="hlt">model</span> show similar trends. More detailed understanding of unsteady characteristics of a turbine flow field can be obtained using the second <span class="hlt">type</span> of interface <span class="hlt">model</span>, the time <span class="hlt">accurate</span> sliding mesh <span class="hlt">model</span>. The potential flow interactions, wake characteristics, their effects on secondary flow formation, and the wake mixing process in a rotor passage were examined using this <span class="hlt">model</span>. Furthermore, turbine stage efficiency and effects of tip clearance height on the turbine stage efficiency were also investigated. A comparison between the results from the circumferential average <span class="hlt">model</span> and the time <span class="hlt">accurate</span> flow <span class="hlt">model</span> results is presented. It was found that the circumferential average <span class="hlt">model</span> cannot <span class="hlt">accurately</span> simulate flow interaction characteristics on the interface plane between the NGV trailing edge and the rotor leading edge. However, the circumferential average <span class="hlt">model</span> does give</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5870536','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5870536"><span>Discriminating the reaction <span class="hlt">types</span> of plant <span class="hlt">type</span> III polyketide synthases</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shimizu, Yugo; Ogata, Hiroyuki; Goto, Susumu</p> <p>2017-01-01</p> <p>Abstract Motivation: Functional prediction of paralogs is challenging in bioinformatics because of rapid functional diversification after gene duplication events combined with parallel acquisitions of similar functions by different paralogs. Plant <span class="hlt">type</span> III polyketide synthases (PKSs), producing various secondary metabolites, represent a paralogous family that has undergone gene duplication and functional alteration. Currently, there is no computational method available for the functional prediction of <span class="hlt">type</span> III PKSs. Results: We developed a plant <span class="hlt">type</span> III PKS reaction predictor, pPAP, based on the recently proposed classification of <span class="hlt">type</span> III PKSs. pPAP combines two kinds of similarity measures: one calculated by profile hidden Markov <span class="hlt">models</span> (pHMMs) built from functionally and structurally important partial sequence regions, and the other based on mutual information between residue positions. pPAP targets PKSs acting on ring-<span class="hlt">type</span> starter substrates, and classifies their functions into four reaction <span class="hlt">types</span>. The pHMM approach discriminated two reaction <span class="hlt">types</span> with high accuracy (97.5%, 39/40), but its accuracy decreased when discriminating three reaction <span class="hlt">types</span> (87.8%, 43/49). When combined with a correlation-based approach, all 49 PKSs were correctly discriminated, and pPAP was still highly <span class="hlt">accurate</span> (91.4%, 64/70) even after adding other reaction <span class="hlt">types</span>. These results suggest pPAP, which is based on linear discriminant analyses of similarity measures, is effective for plant <span class="hlt">type</span> III PKS function prediction. Availability and Implementation: pPAP is freely available at ftp://ftp.genome.jp/pub/tools/ppap/ Contact: goto@kuicr.kyoto-u.ac.jp Supplementary information: Supplementary data are available at Bioinformatics online. PMID:28334262</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1612099S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1612099S"><span>Towards more <span class="hlt">accurate</span> wind and solar power prediction by improving NWP <span class="hlt">model</span> physics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steiner, Andrea; Köhler, Carmen; von Schumann, Jonas; Ritter, Bodo</p> <p>2014-05-01</p> <p> nighttime to well mixed conditions during the day presents a big challenge to NWP <span class="hlt">models</span>. Fast decrease and successive increase in hub-height wind speed after sunrise, and the formation of nocturnal low level jets will be discussed. For PV, the life cycle of low stratus clouds and fog is crucial. Capturing these processes correctly depends on the <span class="hlt">accurate</span> simulation of diffusion or vertical momentum transport and the interaction with other atmospheric and soil processes within the numerical weather <span class="hlt">model</span>. Results from Single Column <span class="hlt">Model</span> simulations and 3d case studies will be presented. Emphasis is placed on wind forecasts; however, some references to highlights concerning the PV-developments will also be given. *) ORKA: Optimierung von Ensembleprognosen regenerativer Einspeisung für den Kürzestfristbereich am Anwendungsbeispiel der Netzsicherheitsrechnungen **) EWeLiNE: Erstellung innovativer Wetter- und Leistungsprognosemodelle für die Netzintegration wetterabhängiger Energieträger, www.projekt-eweline.de</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JMiMi..15S..60P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JMiMi..15S..60P"><span><span class="hlt">Accurate</span> masking technology for high-resolution powder blasting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pawlowski, Anne-Gabrielle; Sayah, Abdeljalil; Gijs, Martin A. M.</p> <p>2005-07-01</p> <p>We have combined eroding 10 µm diameter Al2O3 particles with a new masking technology to realize the smallest and most <span class="hlt">accurate</span> possible structures by powder blasting. Our masking technology is based on the sequential combination of two polymers:(i) the brittle epoxy resin SU8 for its photosensitivity and (ii) the elastic and thermocurable poly-dimethylsiloxane for its large erosion resistance. We have micropatterned various <span class="hlt">types</span> of structures with a minimum width of 20 µm for test structures with an aspect ratio of 1, and 50 µm for test structures with an aspect ratio of 2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120000790','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120000790"><span>Magnetic Helicity and Planetary Dynamos</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shebalin, John V.</p> <p>2012-01-01</p> <p>A <span class="hlt">model</span> planetary dynamo based on the <span class="hlt">Boussinesq</span> approximation along with homogeneous boundary conditions is considered. A statistical theory describing a large-scale MHD dynamo is found, in which magnetic helicity is the critical parameter</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/28570','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/28570"><span>Calculating <span class="hlt">accurate</span> aboveground dry weight biomass of herbaceous vegetation in the Great Plains: A comparison of three calculations to determine the least resource intensive and most <span class="hlt">accurate</span> method</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Ben Butler</p> <p>2007-01-01</p> <p>Obtaining <span class="hlt">accurate</span> biomass measurements is often a resource-intensive task. Data collection crews often spend large amounts of time in the field clipping, drying, and weighing grasses to calculate the biomass of a given vegetation <span class="hlt">type</span>. Such a problem is currently occurring in the Great Plains region of the Bureau of Indian Affairs. A study looked at six reservations...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdSpR..61.1066C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdSpR..61.1066C"><span>A deformation <span class="hlt">model</span> of flexible, HAMR objects for <span class="hlt">accurate</span> propagation under perturbations and the self-shadowing effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Channumsin, Sittiporn; Ceriotti, Matteo; Radice, Gianmarco</p> <p>2018-02-01</p> <p>A new <span class="hlt">type</span> of space debris in near geosynchronous orbit (GEO) was recently discovered and later identified as exhibiting unique characteristics associated with high area-to-mass ratio (HAMR) objects, such as high rotation rates and high reflection properties. Observations have shown that this debris <span class="hlt">type</span> is very sensitive to environmental disturbances, particularly solar radiation pressure, due to the fact that its motion depends on the actual effective area, orientation of that effective area, reflection properties and the area-to-mass ratio of the object is not stable over time. Previous investigations have <span class="hlt">modelled</span> this <span class="hlt">type</span> of debris as rigid bodies (constant area-to-mass ratios) or discrete deformed body; however, these simplifications will lead to inaccurate long term orbital predictions. This paper proposes a simple yet reliable <span class="hlt">model</span> of a thin, deformable membrane based on multibody dynamics. The membrane is <span class="hlt">modelled</span> as a series of flat plates, connected through joints, representing the flexibility of the membrane itself. The mass of the membrane, albeit low, is taken into account through lump masses at the joints. The attitude and orbital motion of this flexible membrane <span class="hlt">model</span> is then propagated near GEO to predict its orbital evolution under the perturbations of solar radiation pressure, Earth's gravity field (J2), third body gravitational fields (the Sun and Moon) and self-shadowing. These results are then compared to those obtained for two rigid body <span class="hlt">models</span> (cannonball and flat rigid plate). In addition, Monte Carlo simulations of the flexible <span class="hlt">model</span> by varying initial attitude and deformation angle (different shape) are investigated and compared with the two rigid <span class="hlt">models</span> (cannonball and flat rigid plate) over a period of 100 days. The numerical results demonstrate that cannonball and rigid flat plate are not appropriate to capture the true dynamical evolution of these objects, at the cost of increased computational time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1194030','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1194030"><span>The CPA Equation of State and an Activity Coefficient <span class="hlt">Model</span> for <span class="hlt">Accurate</span> Molar Enthalpy Calculations of Mixtures with Carbon Dioxide and Water/Brine</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Myint, P. C.; Hao, Y.; Firoozabadi, A.</p> <p>2015-03-27</p> <p>Thermodynamic property calculations of mixtures containing carbon dioxide (CO 2) and water, including brines, are essential in theoretical <span class="hlt">models</span> of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many <span class="hlt">models</span> for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data [1]. In this report, we recommend two different <span class="hlt">models</span> for enthalpy calculations: the CPA equation of state by Li and Firoozabadi [2], and the CO 2 activity coefficient <span class="hlt">model</span> by Duanmore » and Sun [3]. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also <span class="hlt">accurately</span> calculates molar enthalpies of pure CO 2, pure water, and both CO 2-rich and aqueous (H 2O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spycher and Pruess <span class="hlt">model</span>. In aqueous sodium chloride (NaCl) mixtures, we show that Duan and Sun’s <span class="hlt">model</span> yields <span class="hlt">accurate</span> results for the partial molar enthalpy of CO 2. It can be combined with another <span class="hlt">model</span> for the brine enthalpy to calculate the molar enthalpy of H 2O-CO 2-NaCl mixtures. We conclude by explaining how the CPA equation of state may be modified to further improve agreement with experiments. This generalized CPA is the basis of our future work on this topic.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1113148B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1113148B"><span>Mediterranean maquis fuel <span class="hlt">model</span> development and mapping to support fire <span class="hlt">modeling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bacciu, V.; Arca, B.; Pellizzaro, G.; Salis, M.; Ventura, A.; Spano, D.; Duce, P.</p> <p>2009-04-01</p> <p>Fuel load data and fuel <span class="hlt">model</span> maps represent a critical issue for fire spread and behaviour <span class="hlt">modeling</span>. The availability of <span class="hlt">accurate</span> input data at different spatial and temporal scales can allow detailed analysis and predictions of fire hazard and fire effects across a landscape. Fuel <span class="hlt">model</span> data are used in spatially explicit fire growth <span class="hlt">models</span> to attain fire behaviour information for fuel management in prescribed fires, fire management applications, firefighters training, smoke emissions, etc. However, fuel <span class="hlt">type</span> characteristics are difficult to be parameterized due to their complexity and variability: live and dead materials with different size contribute in different ways to the fire spread and behaviour. In the last decades, a strong help was provided by the use of remote sensing imagery at high spatial and spectral resolution. Such techniques are able to capture fine scale fuel distributions for <span class="hlt">accurate</span> fire growth projections. Several attempts carried out in Europe were devoted to fuel classification and map characterization. In Italy, fuel load estimation and fuel <span class="hlt">model</span> definition are still critical issues to be addressed due to the lack of detailed information. In this perspective, the aim of the present work was to propose an integrated approach based on field data collection, fuel <span class="hlt">model</span> development and fuel <span class="hlt">model</span> mapping to provide fuel <span class="hlt">models</span> for the Mediterranean maquis associations. Field data needed for the development of fuel <span class="hlt">models</span> were collected using destructive and non destructive measurements in experimental plots located in Northern Sardinia (Italy). Statistical tests were used to identify the main fuel <span class="hlt">types</span> that were classified into four custom fuel <span class="hlt">models</span>. Subsequently, a supervised classification by the Maximum Likelihood algorithm was applied on IKONOS images to identify and map the different <span class="hlt">types</span> of maquis vegetation. The correspondent fuel <span class="hlt">model</span> was then associated to each vegetation <span class="hlt">type</span> to obtain the fuel <span class="hlt">model</span> map. The results show the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JHEP...06..154A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JHEP...06..154A"><span>NNLOPS <span class="hlt">accurate</span> associated HW production</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Astill, William; Bizon, Wojciech; Re, Emanuele; Zanderighi, Giulia</p> <p>2016-06-01</p> <p>We present a next-to-next-to-leading order <span class="hlt">accurate</span> description of associated HW production consistently matched to a parton shower. The method is based on reweighting events obtained with the HW plus one jet NLO <span class="hlt">accurate</span> calculation implemented in POWHEG, extended with the MiNLO procedure, to reproduce NNLO <span class="hlt">accurate</span> Born distributions. Since the Born kinematics is more complex than the cases treated before, we use a parametrization of the Collins-Soper angles to reduce the number of variables required for the reweighting. We present phenomenological results at 13 TeV, with cuts suggested by the Higgs Cross section Working Group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHEP...11..208B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHEP...11..208B"><span>Neutrinoless double beta decay in <span class="hlt">type</span> I+II seesaw <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borah, Debasish; Dasgupta, Arnab</p> <p>2015-11-01</p> <p>We study neutrinoless double beta decay in left-right symmetric extension of the standard <span class="hlt">model</span> with <span class="hlt">type</span> I and <span class="hlt">type</span> II seesaw origin of neutrino masses. Due to the enhanced gauge symmetry as well as extended scalar sector, there are several new physics sources of neutrinoless double beta decay in this <span class="hlt">model</span>. Ignoring the left-right gauge boson mixing and heavy-light neutrino mixing, we first compute the contributions to neutrinoless double beta decay for <span class="hlt">type</span> I and <span class="hlt">type</span> II dominant seesaw separately and compare with the standard light neutrino contributions. We then repeat the exercise by considering the presence of both <span class="hlt">type</span> I and <span class="hlt">type</span> II seesaw, having non-negligible contributions to light neutrino masses and show the difference in results from individual seesaw cases. Assuming the new gauge bosons and scalars to be around a TeV, we constrain different parameters of the <span class="hlt">model</span> including both heavy and light neutrino masses from the requirement of keeping the new physics contribution to neutrinoless double beta decay amplitude below the upper limit set by the GERDA experiment and also satisfying bounds from lepton flavor violation, cosmology and colliders.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29635963','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29635963"><span>Tau-independent Phase Analysis: A Novel Method for <span class="hlt">Accurately</span> Determining Phase Shifts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tackenberg, Michael C; Jones, Jeff R; Page, Terry L; Hughey, Jacob J</p> <p>2018-06-01</p> <p>Estimations of period and phase are essential in circadian biology. While many techniques exist for estimating period, comparatively few methods are available for estimating phase. Current approaches to analyzing phase often vary between studies and are sensitive to coincident changes in period and the stage of the circadian cycle at which the stimulus occurs. Here we propose a new technique, tau-independent phase analysis (TIPA), for quantifying phase shifts in multiple <span class="hlt">types</span> of circadian time-course data. Through comprehensive simulations, we show that TIPA is both more <span class="hlt">accurate</span> and more precise than the standard actogram approach. TIPA is computationally simple and therefore will enable <span class="hlt">accurate</span> and reproducible quantification of phase shifts across multiple subfields of chronobiology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26142484','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26142484"><span>PredSTP: a highly <span class="hlt">accurate</span> SVM based <span class="hlt">model</span> to predict sequential cystine stabilized peptides.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Islam, S M Ashiqul; Sajed, Tanvir; Kearney, Christopher Michel; Baker, Erich J</p> <p>2015-07-05</p> <p>Numerous organisms have evolved a wide range of toxic peptides for self-defense and predation. Their effective interstitial and macro-environmental use requires energetic and structural stability. One successful group of these peptides includes a tri-disulfide domain arrangement that offers toxicity and high stability. Sequential tri-disulfide connectivity variants create highly compact disulfide folds capable of withstanding a variety of environmental stresses. Their combination of toxicity and stability make these peptides remarkably valuable for their potential as bio-insecticides, antimicrobial peptides and peptide drug candidates. However, the wide sequence variation, sources and modalities of group members impose serious limitations on our ability to rapidly identify potential members. As a result, there is a need for automated high-throughput member classification approaches that leverage their demonstrated tertiary and functional homology. We developed an SVM-based <span class="hlt">model</span> to predict sequential tri-disulfide peptide (STP) toxins from peptide sequences. One optimized <span class="hlt">model</span>, called PredSTP, predicted STPs from training set with sensitivity, specificity, precision, accuracy and a Matthews correlation coefficient of 94.86%, 94.11%, 84.31%, 94.30% and 0.86, respectively, using 200 fold cross validation. The same <span class="hlt">model</span> outperforms existing prediction approaches in three independent out of sample testsets derived from PDB. PredSTP can <span class="hlt">accurately</span> identify a wide range of cystine stabilized peptide toxins directly from sequences in a species-agnostic fashion. The ability to rapidly filter sequences for potential bioactive peptides can greatly compress the time between peptide identification and testing structural and functional properties for possible antimicrobial and insecticidal candidates. A web interface is freely available to predict STP toxins from http://crick.ecs.baylor.edu/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28916110','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28916110"><span>A fast and <span class="hlt">accurate</span> Langmuir-<span class="hlt">type</span> polymer microtensiometer.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gijsenbergh, Pieter; Puers, Robert</p> <p>2018-05-01</p> <p>A semi-flexible polymer microtensiometer for local surface pressure measurements of Langmuir monolayers is presented. The current device geometry and read-out method via image analysis result in a theoretical accuracy of ±0.02mN⋅m -1 for a dynamic range between 0 and 75mN⋅m -1 . The tensiometer sensitivity and dynamic range are easily tunable as they are solely based on the tensiometer spring dimensions. Finite element simulations are used to determine the response time of 20ms for a subphase viscosity of 1mPa⋅s. A poroviscomechanical <span class="hlt">model</span> of the sensor is composed and the subphase viscosity is shown to dominate the transient behavior. The tensiometer performance is verified in a Langmuir trough by applying rapid local surface pressure oscillations. A Wilhelmy plate is used as an independent measurement tool and the results of both techniques correlate well. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820017693&hterms=air+convection+currents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dair%2Bconvection%2Bcurrents','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820017693&hterms=air+convection+currents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dair%2Bconvection%2Bcurrents"><span>A <span class="hlt">model</span> to determine open or closed cellular convection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Helfand, H. M.; Kalnay, E.</p> <p>1981-01-01</p> <p>A simple mechanism is proposed to explain the observed presence in the atmosphere of open or closed cellular convection. If convection is produced by cooling concentrated near the top of the cloud layer, as in radiative cooling of stratus clouds, it develops strong descending currents which are compensated by weak ascent over most of the horizontal area, and closed cells result. Conversely, heating concentrated near the bottom of a layer, as when an air mass is heated by warm water, results in strong ascending currents compensated by weak descent over most of the area, or open cells. This mechanism is similar to the one suggested by Stommel (1962) to explain the smallness of the oceans' sinking regions. The mechanism is studied numerically by means of a two-dimensional, nonlinear <span class="hlt">Boussinesq</span> <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=cyclone&id=EJ255541','ERIC'); return false;" href="https://eric.ed.gov/?q=cyclone&id=EJ255541"><span>Conceptual <span class="hlt">Models</span> of Frontal Cyclones.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Eagleman, Joe R.</p> <p>1981-01-01</p> <p>This discussion of weather <span class="hlt">models</span> uses maps to illustrate the differences among three <span class="hlt">types</span> of frontal cyclones (long wave, short wave, and troughs). Awareness of these cyclones can provide clues to atmospheric conditions which can lead toward <span class="hlt">accurate</span> weather forecasting. (AM)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3251720','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3251720"><span>Probabilistic techniques for obtaining <span class="hlt">accurate</span> patient counts in Clinical Data Warehouses</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Myers, Risa B.; Herskovic, Jorge R.</p> <p>2011-01-01</p> <p>Proposal and execution of clinical trials, computation of quality measures and discovery of correlation between medical phenomena are all applications where an <span class="hlt">accurate</span> count of patients is needed. However, existing sources of this <span class="hlt">type</span> of patient information, including Clinical Data Warehouses (CDW) may be incomplete or inaccurate. This research explores applying probabilistic techniques, supported by the MayBMS probabilistic database, to obtain <span class="hlt">accurate</span> patient counts from a clinical data warehouse containing synthetic patient data. We present a synthetic clinical data warehouse (CDW), and populate it with simulated data using a custom patient data generation engine. We then implement, evaluate and compare different techniques for obtaining patients counts. We <span class="hlt">model</span> billing as a test for the presence of a condition. We compute billing’s sensitivity and specificity both by conducting a “Simulated Expert Review” where a representative sample of records are reviewed and labeled by experts, and by obtaining the ground truth for every record. We compute the posterior probability of a patient having a condition through a “Bayesian Chain”, using Bayes’ Theorem to calculate the probability of a patient having a condition after each visit. The second method is a “one-shot” approach that computes the probability of a patient having a condition based on whether the patient is ever billed for the condition Our results demonstrate the utility of probabilistic approaches, which improve on the accuracy of raw counts. In particular, the simulated review paired with a single application of Bayes’ Theorem produces the best results, with an average error rate of 2.1% compared to 43.7% for the straightforward billing counts. Overall, this research demonstrates that Bayesian probabilistic approaches improve patient counts on simulated patient populations. We believe that total patient counts based on billing data are one of the many possible applications of our</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26599581','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26599581"><span>Total inpatient treatment costs in patients with severe burns: towards a more <span class="hlt">accurate</span> reimbursement <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mehra, Tarun; Koljonen, Virve; Seifert, Burkhardt; Volbracht, Jörk; Giovanoli, Pietro; Plock, Jan; Moos, Rudolf Maria</p> <p>2015-01-01</p> <p>Reimbursement systems have difficulties depicting the actual cost of burn treatment, leaving care providers with a significant financial burden. Our aim was to establish a simple and <span class="hlt">accurate</span> reimbursement <span class="hlt">model</span> compatible with prospective payment systems. A total of 370 966 electronic medical records of patients discharged in 2012 to 2013 from Swiss university hospitals were reviewed. A total of 828 cases of burns including 109 cases of severe burns were retained. Costs, revenues and earnings for severe and nonsevere burns were analysed and a linear regression <span class="hlt">model</span> predicting total inpatient treatment costs was established. The median total costs per case for severe burns was tenfold higher than for nonsevere burns (179 949 CHF [167 353 EUR] vs 11 312 CHF [10 520 EUR], interquartile ranges 96 782-328 618 CHF vs 4 874-27 783 CHF, p <0.001). The median of earnings per case for nonsevere burns was 588 CHF (547 EUR) (interquartile range -6 720 - 5 354 CHF) whereas severe burns incurred a large financial loss to care providers, with median earnings of -33 178 CHF (30 856 EUR) (interquartile range -95 533 - 23 662 CHF). Differences were highly significant (p <0.001). Our linear regression <span class="hlt">model</span> predicting total costs per case with length of stay (LOS) as independent variable had an adjusted R2 of 0.67 (p <0.001 for LOS). Severe burns are systematically underfunded within the Swiss reimbursement system. Flat-rate DRG-based refunds poorly reflect the actual treatment costs. In conclusion, we suggest a reimbursement <span class="hlt">model</span> based on a per diem rate for treatment of severe burns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA597898','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA597898"><span><span class="hlt">Accurate</span> Arabic Script Language/Dialect Classification</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2014-01-01</p> <p>Army Research Laboratory <span class="hlt">Accurate</span> Arabic Script Language/Dialect Classification by Stephen C. Tratz ARL-TR-6761 January 2014 Approved for public...1197 ARL-TR-6761 January 2014 <span class="hlt">Accurate</span> Arabic Script Language/Dialect Classification Stephen C. Tratz Computational and Information Sciences...Include area code) Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 January 2014 Final <span class="hlt">Accurate</span> Arabic Script Language/Dialect Classification</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IJTP...53.2051V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IJTP...53.2051V"><span>Anisotropic Bianchi <span class="hlt">Type</span>-I and <span class="hlt">Type</span>-II Bulk Viscous String Cosmological <span class="hlt">Models</span> Coupled with Zero Mass Scalar Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Venkateswarlu, R.; Sreenivas, K.</p> <p>2014-06-01</p> <p>The LRS Bianchi <span class="hlt">type</span>-I and <span class="hlt">type</span>-II string cosmological <span class="hlt">models</span> are studied when the source for the energy momentum tensor is a bulk viscous stiff fluid containing one dimensional strings together with zero-mass scalar field. We have obtained the solutions of the field equations assuming a functional relationship between metric coefficients when the metric is Bianchi <span class="hlt">type</span>-I and constant deceleration parameter in case of Bianchi <span class="hlt">type</span>-II metric. The physical and kinematical properties of the <span class="hlt">models</span> are discussed in each case. The effects of Viscosity on the physical and kinematical properties are also studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JMoSt1163..472A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JMoSt1163..472A"><span>A simple <span class="hlt">model</span> for cell <span class="hlt">type</span> recognition using 2D-correlation analysis of FTIR images from breast cancer tissue</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ali, Mohamed H.; Rakib, Fazle; Al-Saad, Khalid; Al-Saady, Rafif; Lyng, Fiona M.; Goormaghtigh, Erik</p> <p>2018-07-01</p> <p>Breast cancer is the second most common cancer after lung cancer. So far, in clinical practice, most cancer parameters originating from histopathology rely on the visualization by a pathologist of microscopic structures observed in stained tissue sections, including immunohistochemistry markers. Fourier transform infrared spectroscopy (FTIR) spectroscopy provides a biochemical fingerprint of a biopsy sample and, together with advanced data analysis techniques, can <span class="hlt">accurately</span> classify cell <span class="hlt">types</span>. Yet, one of the challenges when dealing with FTIR imaging is the slow recording of the data. One cm2 tissue section requires several hours of image recording. We show in the present paper that 2D covariance analysis singles out only a few wavenumbers where both variance and covariance are large. Simple <span class="hlt">models</span> could be built using 4 wavenumbers to identify the 4 main cell <span class="hlt">types</span> present in breast cancer tissue sections. Decision trees provide particularly simple <span class="hlt">models</span> to reach discrimination between the 4 cell <span class="hlt">types</span>. The robustness of these simple decision-tree <span class="hlt">models</span> were challenged with FTIR spectral data obtained using different recording conditions. One test set was recorded by transflection on tissue sections in the presence of paraffin while the training set was obtained on dewaxed tissue sections by transmission. Furthermore, the test set was collected with a different brand of FTIR microscope and a different pixel size. Despite the different recording conditions, separating extracellular matrix (ECM) from carcinoma spectra was 100% successful, underlying the robustness of this univariate <span class="hlt">model</span> and the utility of covariance analysis for revealing efficient wavenumbers. We suggest that 2D covariance maps using the full spectral range could be most useful to select the interesting wavenumbers and achieve very fast data acquisition on quantum cascade laser infrared imaging microscopes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10445E..1UM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10445E..1UM"><span><span class="hlt">Modeling</span> of luminance distribution in CAVE-<span class="hlt">type</span> virtual reality systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meironke, Michał; Mazikowski, Adam</p> <p>2017-08-01</p> <p>At present, one of the most advanced virtual reality systems are CAVE-<span class="hlt">type</span> (Cave Automatic Virtual Environment) installations. Such systems are usually consisted of four, five or six projection screens and in case of six screens arranged in form of a cube. Providing the user with a high level of immersion feeling in such systems is largely dependent of optical properties of the system. The <span class="hlt">modeling</span> of physical phenomena plays nowadays a huge role in the most fields of science and technology. It allows to simulate work of device without a need to make any changes in the physical constructions. In this paper distribution of luminance in CAVE-<span class="hlt">type</span> virtual reality systems were <span class="hlt">modelled</span>. Calculations were performed for the <span class="hlt">model</span> of 6-walled CAVE-<span class="hlt">type</span> installation, based on Immersive 3D Visualization Laboratory, situated at the Faculty of Electronics, Telecommunications and Informatics at the Gdańsk University of Technology. Tests have been carried out for two different scattering distribution of the screen material in order to check how these characteristicinfluence on the luminance distribution of the whole CAVE. The basis assumption and simplification of <span class="hlt">modeled</span> CAVE-<span class="hlt">type</span> installation and results were presented. The brief discussion about the results and usefulness of developed <span class="hlt">model</span> were also carried out.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JPhCS..85a2033R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JPhCS..85a2033R"><span>A systematic approach for the <span class="hlt">accurate</span> non-invasive estimation of blood glucose utilizing a novel light-tissue interaction adaptive <span class="hlt">modelling</span> scheme</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rybynok, V. O.; Kyriacou, P. A.</p> <p>2007-10-01</p> <p>Diabetes is one of the biggest health challenges of the 21st century. The obesity epidemic, sedentary lifestyles and an ageing population mean prevalence of the condition is currently doubling every generation. Diabetes is associated with serious chronic ill health, disability and premature mortality. Long-term complications including heart disease, stroke, blindness, kidney disease and amputations, make the greatest contribution to the costs of diabetes care. Many of these long-term effects could be avoided with earlier, more effective monitoring and treatment. Currently, blood glucose can only be monitored through the use of invasive techniques. To date there is no widely accepted and readily available non-invasive monitoring technique to measure blood glucose despite the many attempts. This paper challenges one of the most difficult non-invasive monitoring techniques, that of blood glucose, and proposes a new novel approach that will enable the <span class="hlt">accurate</span>, and calibration free estimation of glucose concentration in blood. This approach is based on spectroscopic techniques and a new adaptive <span class="hlt">modelling</span> scheme. The theoretical implementation and the effectiveness of the adaptive <span class="hlt">modelling</span> scheme for this application has been described and a detailed mathematical evaluation has been employed to prove that such a scheme has the capability of extracting <span class="hlt">accurately</span> the concentration of glucose from a complex biological media.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29773659','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29773659"><span><span class="hlt">Modeling</span> leaderless transcription and atypical genes results in more <span class="hlt">accurate</span> gene prediction in prokaryotes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lomsadze, Alexandre; Gemayel, Karl; Tang, Shiyuyun; Borodovsky, Mark</p> <p>2018-05-17</p> <p>In a conventional view of the prokaryotic genome organization, promoters precede operons and ribosome binding sites (RBSs) with Shine-Dalgarno consensus precede genes. However, recent experimental research suggesting a more diverse view motivated us to develop an algorithm with improved gene-finding accuracy. We describe GeneMarkS-2, an ab initio algorithm that uses a <span class="hlt">model</span> derived by self-training for finding species-specific (native) genes, along with an array of precomputed "heuristic" <span class="hlt">models</span> designed to identify harder-to-detect genes (likely horizontally transferred). Importantly, we designed GeneMarkS-2 to identify several <span class="hlt">types</span> of distinct sequence patterns (signals) involved in gene expression control, among them the patterns characteristic for leaderless transcription as well as noncanonical RBS patterns. To assess the accuracy of GeneMarkS-2, we used genes validated by COG (Clusters of Orthologous Groups) annotation, proteomics experiments, and N-terminal protein sequencing. We observed that GeneMarkS-2 performed better on average in all accuracy measures when compared with the current state-of-the-art gene prediction tools. Furthermore, the screening of ∼5000 representative prokaryotic genomes made by GeneMarkS-2 predicted frequent leaderless transcription in both archaea and bacteria. We also observed that the RBS sites in some species with leadered transcription did not necessarily exhibit the Shine-Dalgarno consensus. The <span class="hlt">modeling</span> of different <span class="hlt">types</span> of sequence motifs regulating gene expression prompted a division of prokaryotic genomes into five categories with distinct sequence patterns around the gene starts. © 2018 Lomsadze et al.; Published by Cold Spring Harbor Laboratory Press.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MRE.....5d6520G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MRE.....5d6520G"><span>Study on elevated-temperature flow behavior of Ni-Cr-Mo-B ultra-heavy-plate steel via experiment and <span class="hlt">modelling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Zhi-yu; Kang, Yu; Li, Yan-shuai; Meng, Chao; Pan, Tao</p> <p>2018-04-01</p> <p>Elevated-temperature flow behavior of a novel Ni-Cr-Mo-B ultra-heavy-plate steel was investigated by conducting hot compressive deformation tests on a Gleeble-3800 thermo-mechanical simulator at a temperature range of 1123 K–1423 K with a strain rate range from 0.01 s‑1 to10 s‑1 and a height reduction of 70%. Based on the experimental results, classic strain-compensated Arrhenius-<span class="hlt">type</span>, a new revised strain-compensated Arrhenius-<span class="hlt">type</span> and classic modified Johnson-Cook constitutive <span class="hlt">models</span> were developed for predicting the high-temperature deformation behavior of the steel. The predictability of these <span class="hlt">models</span> were comparatively evaluated in terms of statistical parameters including correlation coefficient (R), average absolute relative error (AARE), average root mean square error (RMSE), normalized mean bias error (NMBE) and relative error. The statistical results indicate that the new revised strain-compensated Arrhenius-<span class="hlt">type</span> <span class="hlt">model</span> could give prediction of elevated-temperature flow stress for the steel <span class="hlt">accurately</span> under the entire process conditions. However, the predicted values by the classic modified Johnson-Cook <span class="hlt">model</span> could not agree well with the experimental values, and the classic strain-compensated Arrhenius-<span class="hlt">type</span> <span class="hlt">model</span> could track the deformation behavior more <span class="hlt">accurately</span> compared with the modified Johnson-Cook <span class="hlt">model</span>, but less <span class="hlt">accurately</span> with the new revised strain-compensated Arrhenius-<span class="hlt">type</span> <span class="hlt">model</span>. In addition, reasons of differences in predictability of these <span class="hlt">models</span> were discussed in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70019306','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70019306"><span>Friction-term response to boundary-condition <span class="hlt">type</span> in flow <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Schaffranek, R.W.; Lai, C.</p> <p>1996-01-01</p> <p>The friction-slope term in the unsteady open-channel flow equations is examined using two numerical <span class="hlt">models</span> based on different formulations of the governing equations and employing different solution methods. The purposes of the study are to analyze, evaluate, and demonstrate the behavior of the term in a set of controlled numerical experiments using varied <span class="hlt">types</span> and combinations of boundary conditions. Results of numerical experiments illustrate that a given <span class="hlt">model</span> can respond inconsistently for the identical resistance-coefficient value under different <span class="hlt">types</span> and combinations of boundary conditions. Findings also demonstrate that two <span class="hlt">models</span> employing different dependent variables and solution methods can respond similarly for the identical resistance-coefficient value under similar <span class="hlt">types</span> and combinations of boundary conditions. Discussion of qualitative considerations and quantitative experimental results provides insight into the proper treatment, evaluation, and significance of the friction-slope term, thereby offering practical guidelines for <span class="hlt">model</span> implementation and calibration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Poisson&pg=4&id=EJ929724','ERIC'); return false;" href="https://eric.ed.gov/?q=Poisson&pg=4&id=EJ929724"><span>On the Bayesian Nonparametric Generalization of IRT-<span class="hlt">Type</span> <span class="hlt">Models</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>San Martin, Ernesto; Jara, Alejandro; Rolin, Jean-Marie; Mouchart, Michel</p> <p>2011-01-01</p> <p>We study the identification and consistency of Bayesian semiparametric IRT-<span class="hlt">type</span> <span class="hlt">models</span>, where the uncertainty on the abilities' distribution is <span class="hlt">modeled</span> using a prior distribution on the space of probability measures. We show that for the semiparametric Rasch Poisson counts <span class="hlt">model</span>, simple restrictions ensure the identification of a general…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS13A1303W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS13A1303W"><span>Physical and Numerical <span class="hlt">Model</span> Studies of Cross-flow Turbines Towards <span class="hlt">Accurate</span> Parameterization in Array Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wosnik, M.; Bachant, P.</p> <p>2014-12-01</p> <p>Cross-flow turbines, often referred to as vertical-axis turbines, show potential for success in marine hydrokinetic (MHK) and wind energy applications, ranging from small- to utility-scale installations in tidal/ocean currents and offshore wind. As turbine designs mature, the research focus is shifting from individual devices to the optimization of turbine arrays. It would be expensive and time-consuming to conduct physical <span class="hlt">model</span> studies of large arrays at large <span class="hlt">model</span> scales (to achieve sufficiently high Reynolds numbers), and hence numerical techniques are generally better suited to explore the array design parameter space. However, since the computing power available today is not sufficient to conduct simulations of the flow in and around large arrays of turbines with fully resolved turbine geometries (e.g., grid resolution into the viscous sublayer on turbine blades), the turbines' interaction with the energy resource (water current or wind) needs to be parameterized, or <span class="hlt">modeled</span>. <span class="hlt">Models</span> used today--a common <span class="hlt">model</span> is the actuator disk concept--are not able to predict the unique wake structure generated by cross-flow turbines. This wake structure has been shown to create "constructive" interference in some cases, improving turbine performance in array configurations, in contrast with axial-flow, or horizontal axis devices. Towards a more <span class="hlt">accurate</span> parameterization of cross-flow turbines, an extensive experimental study was carried out using a high-resolution turbine test bed with wake measurement capability in a large cross-section tow tank. The experimental results were then "interpolated" using high-fidelity Navier--Stokes simulations, to gain insight into the turbine's near-wake. The study was designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for <span class="hlt">model</span> validation. The end product of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AIPC.1937b0005C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AIPC.1937b0005C"><span>Dimensional reduction for a SIR <span class="hlt">type</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cahyono, Edi; Soeharyadi, Yudi; Mukhsar</p> <p>2018-03-01</p> <p>Epidemic phenomena are often <span class="hlt">modeled</span> in the form of dynamical systems. Such <span class="hlt">model</span> has also been used to <span class="hlt">model</span> spread of rumor, spread of extreme ideology, and dissemination of knowledge. Among the simplest is SIR (susceptible, infected and recovered) <span class="hlt">model</span>, a <span class="hlt">model</span> that consists of three compartments, and hence three variables. The variables are functions of time which represent the number of subpopulations, namely suspect, infected and recovery. The sum of the three is assumed to be constant. Hence, the <span class="hlt">model</span> is actually two dimensional which sits in three-dimensional ambient space. This paper deals with the reduction of a SIR <span class="hlt">type</span> <span class="hlt">model</span> into two variables in two-dimensional ambient space to understand the geometry and dynamics better. The dynamics is studied, and the phase portrait is presented. The two dimensional <span class="hlt">model</span> preserves the equilibrium and the stability. The <span class="hlt">model</span> has been applied for knowledge dissemination, which has been the interest of knowledge management.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title38-vol1/pdf/CFR-2011-title38-vol1-sec4-46.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title38-vol1/pdf/CFR-2011-title38-vol1-sec4-46.pdf"><span>38 CFR 4.46 - <span class="hlt">Accurate</span> measurement.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 <span class="hlt">Accurate</span> measurement. <span class="hlt">Accurate</span>... indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title38-vol1/pdf/CFR-2014-title38-vol1-sec4-46.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title38-vol1/pdf/CFR-2014-title38-vol1-sec4-46.pdf"><span>38 CFR 4.46 - <span class="hlt">Accurate</span> measurement.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 <span class="hlt">Accurate</span> measurement. <span class="hlt">Accurate</span>... indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title38-vol1/pdf/CFR-2010-title38-vol1-sec4-46.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title38-vol1/pdf/CFR-2010-title38-vol1-sec4-46.pdf"><span>38 CFR 4.46 - <span class="hlt">Accurate</span> measurement.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 <span class="hlt">Accurate</span> measurement. <span class="hlt">Accurate</span>... indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title38-vol1/pdf/CFR-2013-title38-vol1-sec4-46.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title38-vol1/pdf/CFR-2013-title38-vol1-sec4-46.pdf"><span>38 CFR 4.46 - <span class="hlt">Accurate</span> measurement.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 <span class="hlt">Accurate</span> measurement. <span class="hlt">Accurate</span>... indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title38-vol1/pdf/CFR-2012-title38-vol1-sec4-46.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title38-vol1/pdf/CFR-2012-title38-vol1-sec4-46.pdf"><span>38 CFR 4.46 - <span class="hlt">Accurate</span> measurement.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-07-01</p> <p>... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 <span class="hlt">Accurate</span> measurement. <span class="hlt">Accurate</span>... indispensable in examinations conducted within the Department of Veterans Affairs. Muscle atrophy must also be...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4918760','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4918760"><span><span class="hlt">Accurate</span> Segmentation of CT Male Pelvic Organs via Regression-based Deformable <span class="hlt">Models</span> and Multi-task Random Forests</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gao, Yaozong; Shao, Yeqin; Lian, Jun; Wang, Andrew Z.; Chen, Ronald C.</p> <p>2016-01-01</p> <p>Segmenting male pelvic organs from CT images is a prerequisite for prostate cancer radiotherapy. The efficacy of radiation treatment highly depends on segmentation accuracy. However, <span class="hlt">accurate</span> segmentation of male pelvic organs is challenging due to low tissue contrast of CT images, as well as large variations of shape and appearance of the pelvic organs. Among existing segmentation methods, deformable <span class="hlt">models</span> are the most popular, as shape prior can be easily incorporated to regularize the segmentation. Nonetheless, the sensitivity to initialization often limits their performance, especially for segmenting organs with large shape variations. In this paper, we propose a novel approach to guide deformable <span class="hlt">models</span>, thus making them robust against arbitrary initializations. Specifically, we learn a displacement regressor, which predicts 3D displacement from any image voxel to the target organ boundary based on the local patch appearance. This regressor provides a nonlocal external force for each vertex of deformable <span class="hlt">model</span>, thus overcoming the initialization problem suffered by the traditional deformable <span class="hlt">models</span>. To learn a reliable displacement regressor, two strategies are particularly proposed. 1) A multi-task random forest is proposed to learn the displacement regressor jointly with the organ classifier; 2) an auto-context <span class="hlt">model</span> is used to iteratively enforce structural information during voxel-wise prediction. Extensive experiments on 313 planning CT scans of 313 patients show that our method achieves better results than alternative classification or regression based methods, and also several other existing methods in CT pelvic organ segmentation. PMID:26800531</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=golf&pg=2&id=EJ990084','ERIC'); return false;" href="https://eric.ed.gov/?q=golf&pg=2&id=EJ990084"><span>Feedback about More <span class="hlt">Accurate</span> versus Less <span class="hlt">Accurate</span> Trials: Differential Effects on Self-Confidence and Activation</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Badami, Rokhsareh; VaezMousavi, Mohammad; Wulf, Gabriele; Namazizadeh, Mahdi</p> <p>2012-01-01</p> <p>One purpose of the present study was to examine whether self-confidence or anxiety would be differentially affected by feedback from more <span class="hlt">accurate</span> rather than less <span class="hlt">accurate</span> trials. The second purpose was to determine whether arousal variations (activation) would predict performance. On Day 1, participants performed a golf putting task under one of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1338727','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1338727"><span>HPC Institutional Computing Project: W15_lesreactiveflow KIVA-hpFE Development: A Robust and <span class="hlt">Accurate</span> Engine <span class="hlt">Modeling</span> Software</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Carrington, David Bradley; Waters, Jiajia</p> <p></p> <p>KIVA-hpFE is a high performance computer software for solving the physics of multi-species and multiphase turbulent reactive flow in complex geometries having immersed moving parts. The code is written in Fortran 90/95 and can be used on any computer platform with any popular complier. The code is in two versions, a serial version and a parallel version utilizing MPICH2 <span class="hlt">type</span> Message Passing Interface (MPI or Intel MPI) for solving distributed domains. The parallel version is at least 30x faster than the serial version and much faster than our previous generation of parallel engine <span class="hlt">modeling</span> software, by many factors. The 5thmore » generation algorithm construction is a Galerkin <span class="hlt">type</span> Finite Element Method (FEM) solving conservative momentum, species, and energy transport equations along with two-equation turbulent <span class="hlt">model</span> k-ω Reynolds Averaged Navier-Stokes (RANS) <span class="hlt">model</span> and a Vreman <span class="hlt">type</span> dynamic Large Eddy Simulation (LES) method. The LES method is capable <span class="hlt">modeling</span> transitional flow from laminar to fully turbulent; therefore, this LES method does not require special hybrid or blending to walls. The FEM projection method also uses a Petrov-Galerkin (P-G) stabilization along with pressure stabilization. We employ hierarchical basis sets, constructed on the fly with enrichment in areas associated with relatively larger error as determined by error estimation methods. In addition, when not using the hp-adaptive module, the code employs Lagrangian basis or shape functions. The shape functions are constructed for hexahedral, prismatic and tetrahedral elements. The software is designed to solve many <span class="hlt">types</span> of reactive flow problems, from burners to internal combustion engines and turbines. In addition, the formulation allows for direct integration of solid bodies (conjugate heat transfer), as in heat transfer through housings, parts, cylinders. It can also easily be extended to stress <span class="hlt">modeling</span> of solids, used in fluid structure interactions problems, solidification, porous</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.1168F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.1168F"><span>On the assimilation of SWOT <span class="hlt">type</span> data into 2D shallow-water <span class="hlt">models</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frédéric, Couderc; Denis, Dartus; Pierre-André, Garambois; Ronan, Madec; Jérôme, Monnier; Jean-Paul, Villa</p> <p>2013-04-01</p> <p>In river hydraulics, assimilation of water level measurements at gauging stations is well controlled, while assimilation of images is still delicate. In the present talk, we address the richness of satellite mapped information to constrain a 2D shallow-water <span class="hlt">model</span>, but also related difficulties. 2D shallow <span class="hlt">models</span> may be necessary for small scale <span class="hlt">modelling</span> in particular for low-water and flood plain flows. Since in both cases, the dynamics of the wet-dry front is essential, one has to elaborate robust and <span class="hlt">accurate</span> solvers. In this contribution we introduce robust second order, stable finite volume scheme [CoMaMoViDaLa]. Comparisons of real like tests cases with more classical solvers highlight the importance of an <span class="hlt">accurate</span> flood plain <span class="hlt">modelling</span>. A preliminary inverse study is presented in a flood plain flow case, [LaMo] [HoLaMoPu]. As a first step, a 0th order data processing <span class="hlt">model</span> improves observation operator and produces more reliable water level derived from rough measurements [PuRa]. Then, both <span class="hlt">model</span> and flow behaviours can be better understood thanks to variational sensitivities based on a gradient computation and adjoint equations. It can reveal several difficulties that a <span class="hlt">model</span> designer has to tackle. Next, a 4D-Var data assimilation algorithm used with spatialized data leads to improved <span class="hlt">model</span> calibration and potentially leads to identify river discharges. All the algorithms are implemented into DassFlow software (Fortran, MPI, adjoint) [Da]. All these results and experiments (<span class="hlt">accurate</span> wet-dry front dynamics, sensitivities analysis, identification of discharges and calibration of <span class="hlt">model</span>) are currently performed in view to use data from the future SWOT mission. [CoMaMoViDaLa] F. Couderc, R. Madec, J. Monnier, J.-P. Vila, D. Dartus, K. Larnier. "Sensitivity analysis and variational data assimilation for geophysical shallow water flows". Submitted. [Da] DassFlow - Data Assimilation for Free Surface Flows. Computational software http</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25514215','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25514215"><span><span class="hlt">Modeling</span> neuropeptide transport in various <span class="hlt">types</span> of nerve terminals containing en passant boutons.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kuznetsov, I A; Kuznetsov, A V</p> <p>2015-03-01</p> <p>We developed a mathematical <span class="hlt">model</span> for simulating neuropeptide transport inside dense core vesicles (DCVs) in axon terminals containing en passant boutons. The motivation for this research is a recent experimental study by Levitan and colleagues (Bulgari et al., 2014) which described DCV transport in nerve terminals of <span class="hlt">type</span> Ib and <span class="hlt">type</span> III as well as in nerve terminals of <span class="hlt">type</span> Ib with the transcription factor DIMM. The goal of our <span class="hlt">modeling</span> is validating the proposition put forward by Levitan and colleagues that the dramatic difference in DCV number in <span class="hlt">type</span> Ib and <span class="hlt">type</span> III terminals can be explained by the difference in DCV capture in <span class="hlt">type</span> Ib and <span class="hlt">type</span> III boutons rather than by differences in DCV anterograde transport and half-life of resident DCVs. The developed <span class="hlt">model</span> provides a tool for studying the dynamics of DCV transport in various <span class="hlt">types</span> of nerve terminals. The <span class="hlt">model</span> is also an important step in gaining a better mechanistic understanding of transport processes in axons and identifying directions for the development of new <span class="hlt">models</span> in this area. Copyright © 2014 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29717401','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29717401"><span><span class="hlt">Modelling</span> mortality and discharge of hospitalized stroke patients using a phase-<span class="hlt">type</span> recovery <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jones, Bruce; McClean, Sally; Stanford, David</p> <p>2018-05-01</p> <p>We <span class="hlt">model</span> the length of in-patient hospital stays due to stroke and the mode of discharge using a phase-<span class="hlt">type</span> stroke recovery <span class="hlt">model</span>. The <span class="hlt">model</span> allows for three different <span class="hlt">types</span> of stroke: haemorrhagic (the most severe, caused by ruptured blood vessels that cause brain bleeding), cerebral infarction (less severe, caused by blood clots) and transient ischemic attack or TIA (the least severe, a mini-stroke caused by a temporary blood clot). A four-phase recovery process is used, where the initial phase depends on the <span class="hlt">type</span> of stroke, and transition from one phase to the next depends on the age of the patient. There are three differing modes of absorption for this phase-<span class="hlt">type</span> <span class="hlt">model</span>: from a typical recovery phase, a patient may die (mode 1), be transferred to a nursing home (mode 2) or be discharged to the individual's usual residence (mode 3). The first recovery phase is characterized by a very high rate of mortality and very low rates of discharge by the other two modes. The next two recovery phases have progressively lower mortality rates and higher mode 2 and 3 discharge rates. The fourth recovery phase is visited only by those who experience a very mild TIA, and they are discharged to home after a short stay. The novelty of our approach to phase representation is two-fold: first, it aligns the phases with labelled diagnosis states, representing stages of illness severity; second, the <span class="hlt">model</span> allows us to obtain expressions for Key Performance Indicators that are of use to healthcare professionals. This allows us to use a backward estimation process where we leverage the fact that we know the phase of admission (the diagnosis), but not which phases are subsequently entered or when this happens; this strategy improves both computational efficiency and accuracy. The <span class="hlt">model</span> has clear practical value as it yields length of stay distributions by age and <span class="hlt">type</span> of stroke, which are useful in resource planning. Also, inclusion of the three modes of discharge permits analyses of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910012137','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910012137"><span>GEOSIM: A numerical <span class="hlt">model</span> for geophysical fluid flow simulation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Butler, Karen A.; Miller, Timothy L.; Lu, Huei-Iin</p> <p>1991-01-01</p> <p>A numerical <span class="hlt">model</span> which simulates geophysical fluid flow in a wide range of problems is described in detail, and comparisons of some of the <span class="hlt">model</span>'s results are made with previous experimental and numerical studies. The <span class="hlt">model</span> is based upon the <span class="hlt">Boussinesq</span> Navier-Stokes equations in spherical coordinates, which can be reduced to a cylindrical system when latitudinal walls are used near the pole and the ratio of latitudinal length to the radius of the sphere is small. The equations are approximated by finite differences in the meridional plane and spectral decomposition in the azimuthal direction. The user can specify a variety of boundary and initial conditions, and there are five different spectral truncation options. The results of five validation cases are presented: (1) the transition between axisymmetric flow and baroclinic wave flow in the side heated annulus; (2) the steady baroclinic wave of the side heated annulus; (3) the wave amplitude vacillation of the side heated annulus; (4) transition to baroclinic wave flow in a bottom heated annulus; and (5) the Spacelab Geophysical Fluid Flow Cell (spherical) experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018CMT....30..301B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018CMT....30..301B"><span>Rigorous derivation of the effective <span class="hlt">model</span> describing a non-isothermal fluid flow in a vertical pipe filled with porous medium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beneš, Michal; Pažanin, Igor</p> <p>2018-03-01</p> <p>This paper reports an analytical investigation of non-isothermal fluid flow in a thin (or long) vertical pipe filled with porous medium via asymptotic analysis. We assume that the fluid inside the pipe is cooled (or heated) by the surrounding medium and that the flow is governed by the prescribed pressure drop between pipe's ends. Starting from the dimensionless Darcy-Brinkman-<span class="hlt">Boussinesq</span> system, we formally derive a macroscopic <span class="hlt">model</span> describing the effective flow at small Brinkman-Darcy number. The asymptotic approximation is given by the explicit formulae for the velocity, pressure and temperature clearly acknowledging the effects of the cooling (heating) and porous structure. The theoretical error analysis is carried out to indicate the order of accuracy and to provide a rigorous justification of the effective <span class="hlt">model</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18407861','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18407861"><span>Nonlinear dynamic analysis of traveling wave-<span class="hlt">type</span> ultrasonic motors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nakagawa, Yosuke; Saito, Akira; Maeno, Takashi</p> <p>2008-03-01</p> <p>In this paper, nonlinear dynamic response of a traveling wave-<span class="hlt">type</span> ultrasonic motor was investigated. In particular, understanding the transient dynamics of a bar-<span class="hlt">type</span> ultrasonic motor, such as starting up and stopping, is of primary interest. First, the transient response of the bar-<span class="hlt">type</span> ultrasonic motor at starting up and stopping was measured using a laser Doppler velocimeter, and its driving characteristics are discussed in detail. The motor is shown to possess amplitude-dependent nonlinearity that greatly influences the transient dynamics of the motor. Second, a dynamical <span class="hlt">model</span> of the motor was constructed as a second-order nonlinear oscillator, which represents the dynamics of the piezoelectric ceramic, stator, and rotor. The <span class="hlt">model</span> features nonlinearities caused by the frictional interface between the stator and the rotor, and cubic nonlinearity in the dynamics of the stator. Coulomb's friction <span class="hlt">model</span> was employed for the interface <span class="hlt">model</span>, and a stick-slip phenomenon is considered. Lastly, it was shown that the <span class="hlt">model</span> is capable of representing the transient dynamics of the motor <span class="hlt">accurately</span>. The critical parameters in the <span class="hlt">model</span> were identified from measured results, and numerical simulations were conducted using the <span class="hlt">model</span> with the identified parameters. Good agreement between the results of measurements and numerical simulations is observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Types+AND+de+AND+performance&pg=4&id=EJ931895','ERIC'); return false;" href="https://eric.ed.gov/?q=Types+AND+de+AND+performance&pg=4&id=EJ931895"><span>Comparing Two <span class="hlt">Types</span> of <span class="hlt">Model</span> Progression in an Inquiry Learning Environment with <span class="hlt">Modelling</span> Facilities</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mulder, Yvonne G.; Lazonder, Ard W.; de Jong, Ton</p> <p>2011-01-01</p> <p>The educational advantages of inquiry learning environments that incorporate <span class="hlt">modelling</span> facilities are often challenged by students' poor inquiry skills. This study examined two <span class="hlt">types</span> of <span class="hlt">model</span> progression as means to compensate for these skill deficiencies. <span class="hlt">Model</span> order progression (MOP), the predicted optimal variant, gradually increases the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1225268','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1225268"><span>Aqueous Solution Vessel Thermal <span class="hlt">Model</span> Development II</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Buechler, Cynthia Eileen</p> <p>2015-10-28</p> <p>The work presented in this report is a continuation of the work described in the May 2015 report, “Aqueous Solution Vessel Thermal <span class="hlt">Model</span> Development”. This computational fluid dynamics (CFD) <span class="hlt">model</span> aims to predict the temperature and bubble volume fraction in an aqueous solution of uranium. These values affect the reactivity of the fissile solution, so it is important to be able to calculate them and determine their effects on the reaction. Part A of this report describes some of the parameter comparisons performed on the CFD <span class="hlt">model</span> using Fluent. Part B describes the coupling of the Fluent <span class="hlt">model</span> with amore » Monte-Carlo N-Particle (MCNP) neutron transport <span class="hlt">model</span>. The fuel tank geometry is the same as it was in the May 2015 report, annular with a thickness-to-height ratio of 0.16. An accelerator-driven neutron source provides the excitation for the reaction, and internal and external water cooling channels remove the heat. The <span class="hlt">model</span> used in this work incorporates the Eulerian multiphase <span class="hlt">model</span> with lift, wall lubrication, turbulent dispersion and turbulence interaction. The buoyancy-driven flow is <span class="hlt">modeled</span> using the <span class="hlt">Boussinesq</span> approximation, and the flow turbulence is determined using the k-ω Shear-Stress-Transport (SST) <span class="hlt">model</span>. The dispersed turbulence multiphase <span class="hlt">model</span> is employed to capture the multiphase turbulence effects.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29414993','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29414993"><span><span class="hlt">Accurately</span> tracking single-cell movement trajectories in microfluidic cell sorting devices.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jeong, Jenny; Frohberg, Nicholas J; Zhou, Enlu; Sulchek, Todd; Qiu, Peng</p> <p>2018-01-01</p> <p>Microfluidics are routinely used to study cellular properties, including the efficient quantification of single-cell biomechanics and label-free cell sorting based on the biomechanical properties, such as elasticity, viscosity, stiffness, and adhesion. Both quantification and sorting applications require optimal design of the microfluidic devices and mathematical <span class="hlt">modeling</span> of the interactions between cells, fluid, and the channel of the device. As a first step toward building such a mathematical <span class="hlt">model</span>, we collected video recordings of cells moving through a ridged microfluidic channel designed to compress and redirect cells according to cell biomechanics. We developed an efficient algorithm that automatically and <span class="hlt">accurately</span> tracked the cell trajectories in the recordings. We tested the algorithm on recordings of cells with different stiffness, and showed the correlation between cell stiffness and the tracked trajectories. Moreover, the tracking algorithm successfully picked up subtle differences of cell motion when passing through consecutive ridges. The algorithm for <span class="hlt">accurately</span> tracking cell trajectories paves the way for future efforts of <span class="hlt">modeling</span> the flow, forces, and dynamics of cell properties in microfluidics applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...809...37B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...809...37B"><span>Theoretical Clues to the Ultraviolet Diversity of <span class="hlt">Type</span> Ia Supernovae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Peter J.; Baron, E.; Milne, Peter; Roming, Peter W. A.; Wang, Lifan</p> <p>2015-08-01</p> <p>The effect of metallicity on the observed light of <span class="hlt">Type</span> Ia supernovae (SNe Ia) could lead to systematic errors as the absolute magnitudes of local and distant SNe Ia are compared to measure luminosity distances and determine cosmological parameters. The UV light may be especially sensitive to metallicity, though different <span class="hlt">modeling</span> methods disagree as to the magnitude, wavelength dependence, and even the sign of the effect. The outer density structure, 56Ni, and to a lesser degree asphericity, also impact the UV. We compute synthetic photometry of various metallicity-dependent <span class="hlt">models</span> and compare to UV/optical photometry from the Swift Ultra-Violet/Optical Telescope. We find that the scatter in the mid-UV to near-UV colors is larger than predicted by changes in metallicity alone and is not consistent with reddening. We demonstrate that a recently employed method to determine relative abundances using UV spectra can be done using UVOT photometry, but we warn that <span class="hlt">accurate</span> results require an <span class="hlt">accurate</span> <span class="hlt">model</span> of the cause of the variations. The abundance of UV photometry now available should provide constraints on <span class="hlt">models</span> that typically rely on UV spectroscopy for constraining metallicity, density, and other parameters. Nevertheless, UV spectroscopy for a variety of supernova explosions is still needed to guide the creation of <span class="hlt">accurate</span> <span class="hlt">models</span>. A better understanding of the influences affecting the UV is important for using SNe Ia as cosmological probes, as the UV light may test whether SNe Ia are significantly affected by evolutionary effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5409456','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5409456"><span>Personalized glucose forecasting for <span class="hlt">type</span> 2 diabetes using data assimilation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Albers, David J.; Gluckman, Bruce; Ginsberg, Henry; Hripcsak, George; Mamykina, Lena</p> <p>2017-01-01</p> <p><span class="hlt">Type</span> 2 diabetes leads to premature death and reduced quality of life for 8% of Americans. Nutrition management is critical to maintaining glycemic control, yet it is difficult to achieve due to the high individual differences in glycemic response to nutrition. Anticipating glycemic impact of different meals can be challenging not only for individuals with diabetes, but also for expert diabetes educators. Personalized computational <span class="hlt">models</span> that can <span class="hlt">accurately</span> forecast an impact of a given meal on an individual’s blood glucose levels can serve as the engine for a new generation of decision support tools for individuals with diabetes. However, to be useful in practice, these computational engines need to generate <span class="hlt">accurate</span> forecasts based on limited datasets consistent with typical self-monitoring practices of individuals with <span class="hlt">type</span> 2 diabetes. This paper uses three forecasting machines: (i) data assimilation, a technique borrowed from atmospheric physics and engineering that uses Bayesian <span class="hlt">modeling</span> to infuse data with human knowledge represented in a mechanistic <span class="hlt">model</span>, to generate real-time, personalized, adaptable glucose forecasts; (ii) <span class="hlt">model</span> averaging of data assimilation output; and (iii) dynamical Gaussian process <span class="hlt">model</span> regression. The proposed data assimilation machine, the primary focus of the paper, uses a modified dual unscented Kalman filter to estimate states and parameters, personalizing the mechanistic <span class="hlt">models</span>. <span class="hlt">Model</span> selection is used to make a personalized <span class="hlt">model</span> selection for the individual and their measurement characteristics. The data assimilation forecasts are empirically evaluated against actual postprandial glucose measurements captured by individuals with <span class="hlt">type</span> 2 diabetes, and against predictions generated by experienced diabetes educators after reviewing a set of historical nutritional records and glucose measurements for the same individual. The evaluation suggests that the data assimilation forecasts compare well with specific glucose measurements</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=typing&pg=4&id=EJ716610','ERIC'); return false;" href="https://eric.ed.gov/?q=typing&pg=4&id=EJ716610"><span>ABO/Rh Blood-<span class="hlt">Typing</span> <span class="hlt">Model</span>: A Problem-Solving Activity</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wake, Carol</p> <p>2005-01-01</p> <p>An ARO/Rh Blood-<span class="hlt">Typing</span> kit useful for students to visualize blood-<span class="hlt">typing</span> activities and practice problem-solving skills with transfusion reactions is presented. The <span class="hlt">model</span> also enables students to identify relationships between A, B, and Rh antigens and antibodies in blood and to understand molecular mechanisms involved in transfusion agglutination…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8485E..0IM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8485E..0IM"><span>Reverse radiance: a fast <span class="hlt">accurate</span> method for determining luminance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moore, Kenneth E.; Rykowski, Ronald F.; Gangadhara, Sanjay</p> <p>2012-10-01</p> <p>Reverse ray tracing from a region of interest backward to the source has long been proposed as an efficient method of determining luminous flux. The idea is to trace rays only from where the final flux needs to be known back to the source, rather than tracing in the forward direction from the source outward to see where the light goes. Once the reverse ray reaches the source, the radiance the equivalent forward ray would have represented is determined and the resulting flux computed. Although reverse ray tracing is conceptually simple, the method critically depends upon an <span class="hlt">accurate</span> source <span class="hlt">model</span> in both the near and far field. An overly simplified source <span class="hlt">model</span>, such as an ideal Lambertian surface substantially detracts from the accuracy and thus benefit of the method. This paper will introduce an improved method of reverse ray tracing that we call Reverse Radiance that avoids assumptions about the source properties. The new method uses measured data from a Source Imaging Goniometer (SIG) that simultaneously measures near and far field luminous data. Incorporating this data into a fast reverse ray tracing integration method yields fast, <span class="hlt">accurate</span> data for a wide variety of illumination problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJST.225.1505H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJST.225.1505H"><span><span class="hlt">Accurate</span> and general treatment of electrostatic interaction in Hamiltonian adaptive resolution simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heidari, M.; Cortes-Huerto, R.; Donadio, D.; Potestio, R.</p> <p>2016-10-01</p> <p>In adaptive resolution simulations the same system is concurrently <span class="hlt">modeled</span> with different resolution in different subdomains of the simulation box, thereby enabling an <span class="hlt">accurate</span> description in a small but relevant region, while the rest is treated with a computationally parsimonious <span class="hlt">model</span>. In this framework, electrostatic interaction, whose <span class="hlt">accurate</span> treatment is a crucial aspect in the realistic <span class="hlt">modeling</span> of soft matter and biological systems, represents a particularly acute problem due to the intrinsic long-range nature of Coulomb potential. In the present work we propose and validate the usage of a short-range modification of Coulomb potential, the Damped shifted force (DSF) <span class="hlt">model</span>, in the context of the Hamiltonian adaptive resolution simulation (H-AdResS) scheme. This approach, which is here validated on bulk water, ensures a reliable reproduction of the structural and dynamical properties of the liquid, and enables a seamless embedding in the H-AdResS framework. The resulting dual-resolution setup is implemented in the LAMMPS simulation package, and its customized version employed in the present work is made publicly available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AIPC.1637..796P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AIPC.1637..796P"><span><span class="hlt">Modeling</span> terminal ballistics using blending-<span class="hlt">type</span> spline surfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pedersen, Aleksander; Bratlie, Jostein; Dalmo, Rune</p> <p>2014-12-01</p> <p>We explore using GERBS, a blending-<span class="hlt">type</span> spline construction, to represent deform able thin-plates and <span class="hlt">model</span> terminal ballistics. Strategies to construct geometry for different scenarios of terminal ballistics are proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDA19005S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDA19005S"><span>Surfactants non-monotonically modify the onset of Faraday waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strickland, Stephen; Shearer, Michael; Daniels, Karen</p> <p>2017-11-01</p> <p>When a water-filled container is vertically vibrated, subharmonic Faraday waves emerge once the driving from the vibrations exceeds viscous dissipation. In the presence of an insoluble surfactant, a viscous boundary layer forms at the contaminated surface to balance the Marangoni and <span class="hlt">Boussinesq</span> stresses. For linear gravity-capillary waves in an undriven fluid, the surfactant-induced boundary layer increases the amount of viscous dissipation. In our analysis and experiments, we consider whether similar effects occur for nonlinear Faraday (gravity-capillary) waves. Assuming a finite-depth, infinite-breadth, low-viscosity fluid, we derive an analytic expression for the onset acceleration up to second order in ɛ =√{ 1 / Re } . This expression allows us to include fluid depth and driving frequency as parameters, in addition to the Marangoni and <span class="hlt">Boussinesq</span> numbers. For millimetric fluid depths and driving frequencies of 30 to 120 Hz, our analysis recovers prior numerical results and agrees with our measurements of NBD-PC surfactant on DI water. In both case, the onset acceleration increases non-monotonically as a function of Marangoni and <span class="hlt">Boussinesq</span> numbers. For shallower systems, our <span class="hlt">model</span> predicts that surfactants could decrease the onset acceleration. DMS-0968258.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA622106','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA622106"><span>CMS-Wave</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2014-10-27</p> <p>a phase-averaged spectral wind-wave generation and transformation <span class="hlt">model</span> and its interface in the Surface-water <span class="hlt">Modeling</span> System (SMS). Ambrose...applications of the <span class="hlt">Boussinesq</span> (BOUSS-2D) wave <span class="hlt">model</span> that provides more rigorous calculations for design and performance optimization of integrated...navigation systems . Together these wave <span class="hlt">models</span> provide reliable predictions on regional and local spatial domains and cost-effective engineering solutions</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. Their policies may differ from this site.</div> </div><!-- container --> <footer><a id="backToTop" href="#top"> </a><nav><a id="backToTop" href="#top"> </a><ul class="links"><a id="backToTop" href="#top"> </a><li><a id="backToTop" href="#top"></a><a href="/sitemap.html">Site Map</a></li> <li><a href="/members/index.html">Members Only</a></li> <li><a href="/website-policies.html">Website Policies</a></li> <li><a href="https://doe.responsibledisclosure.com/hc/en-us" target="_blank">Vulnerability Disclosure Program</a></li> <li><a href="/contact.html">Contact Us</a></li> </ul> <div class="small">Science.gov is maintained by the U.S. Department of Energy's <a href="https://www.osti.gov/" target="_blank">Office of Scientific and Technical Information</a>, in partnership with <a href="https://www.cendi.gov/" target="_blank">CENDI</a>.</div> </nav> </footer> <script type="text/javascript"><!-- // var lastDiv = ""; function showDiv(divName) { // hide last div if (lastDiv) { document.getElementById(lastDiv).className = "hiddenDiv"; } //if value of the box is not nothing and an object with that name exists, then change the class if (divName && document.getElementById(divName)) { document.getElementById(divName).className = "visibleDiv"; lastDiv = divName; } } //--> </script> <script> /** * Function that tracks a click on an outbound link in Google Analytics. * This function takes a valid URL string as an argument, and uses that URL string * as the event label. */ var trackOutboundLink = function(url,collectionCode) { try { h = window.open(url); setTimeout(function() { ga('send', 'event', 'topic-page-click-through', collectionCode, url); }, 1000); } catch(err){} }; </script> <!-- Google Analytics --> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-1122789-34', 'auto'); ga('send', 'pageview'); </script> <!-- End Google Analytics --> <script> showDiv('page_1') </script> </body> </html>