Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model
NASA Technical Reports Server (NTRS)
Kory, Carol L.; Andro, Monty; Downey, Alan (Technical Monitor)
2001-01-01
For the first time, a physics based computational model has been used to provide a direct description of the effects of the TWT (Traveling Wave Tube) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept amplitude and/or swept frequency data. The fully three-dimensional (3D), time-dependent, TWT interaction model using the electromagnetic code MAFIA is presented. This model is used to investigate assumptions made in TWT black box models used in communication system level simulations. In addition, digital signal performance, including intersymbol interference (ISI), is compared using direct data input into the MAFIA model and using the system level analysis tool, SPW (Signal Processing Worksystem).
Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model
NASA Technical Reports Server (NTRS)
Kory, Carol L.; Andro, Monty
2002-01-01
For the first time, a time-dependent, physics-based computational model has been used to provide a direct description of the effects of the traveling wave tube amplifier (TWTA) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry and operating characteristics of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept- amplitude and/or swept-frequency data. First, the TWT model using the three dimensional (3D) electromagnetic code MAFIA is presented. Then, this comprehensive model is used to investigate approximations made in conventional TWT black-box models used in communication system level simulations. To quantitatively demonstrate the effects these approximations have on digital signal performance predictions, including intersymbol interference (ISI), the MAFIA results are compared to the system level analysis tool, Signal Processing Workstation (SPW), using high order modulation schemes including 16 and 64-QAM.
Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model
NASA Technical Reports Server (NTRS)
Kory, Carol L.; Andro, Monty
2002-01-01
For the first time, a time-dependent, physics-based computational model has been used to provide a direct description of the effects of the traveling wave tube amplifier (TWTA) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry and operating characteristics of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept- amplitude and/or swept-frequency data. First, the TWT model using the three dimensional (3D) electromagnetic code MAFIA is presented. Then, this comprehensive model is used to investigate approximations made in conventional TWT black-box models used in communication system level simulations. To quantitatively demonstrate the effects these approximations have on digital signal performance predictions, including intersymbol interference (ISI), the MAFIA results are compared to the system level analysis tool, Signal Processing Workstation (SPW), using high order modulation schemes including 16 and 64-QAM.
3D time dependent thermo-fluid dynamic model of ground deformation at Campi Flegrei caldera
NASA Astrophysics Data System (ADS)
Castaldo, R.; Tizzani, P.; Manconi, A.; Manzo, M.; Pepe, S.; Pepe, A.; Lanari, R.
2012-04-01
In active volcanic areas deformation signals are generally characterized by non-linear spatial and temporal variations [Tizzani P. et al., 2007]. This behaviour has been revealed in the last two decades by the so-called advanced DInSAR processing algorithms, developed to analyze surface deformation phenomena [Berardino P. et al., 2002; Ferretti C. et al., 2001]. Notwithstanding, most of the inverse modelling attempts to characterize the evolution of the volcanic sources are based on the assumption that the Earth's crust behaves as a homogeneous linear elastic material. However, the behaviour of the upper lithosphere in thermally anomalous regions (as active volcanoes are) might be well described as a non-Newtonian fluid, where some of the material proprieties of the rocks (i.e., apparent viscosities) can change over time [Pinkerton H. et al., 1995]. In this context, we considered the thermal proprieties and mechanical heterogeneities of the upper crust in order to develop a new 3D time dependent thermo-fluid dynamic model of Campi Flegrei (CF) caldera, Southern Italy. More specifically, according to Tizzani P. et al. (2010), we integrated in a FEM environment geophysical information (gravimetric, seismic, and borehole data) available for the considered area and performed two FEM optimization procedures to constrain the 3D distribution of unknown physical parameters (temperature and viscosity distributions) that might help explaining the data observed at surface (geothermal wells and DInSAR measurements). First, we searched for the heat production, the volume source distribution and surface emissivity parameters providing the best-fit of the geothermal profiles data measured at six boreholes [Agip ESGE, 1986], by solving the Fourier heat equation over time (about 40 kys). The 3D thermal field resulting from this optimization was used to calculate the 3D brittle-ductile transition. This analysis revealed the presence of a ductile region, located beneath the centre of
Radiation and polarization signatures of the 3D multizone time-dependent hadronic blazar model
Zhang, Haocheng; Diltz, Chris; Bottcher, Markus
2016-09-23
We present a newly developed time-dependent three-dimensional multizone hadronic blazar emission model. By coupling a Fokker–Planck-based lepto-hadronic particle evolution code, 3DHad, with a polarization-dependent radiation transfer code, 3DPol, we are able to study the time-dependent radiation and polarization signatures of a hadronic blazar model for the first time. Our current code is limited to parameter regimes in which the hadronic γ-ray output is dominated by proton synchrotron emission, neglecting pion production. Our results demonstrate that the time-dependent flux and polarization signatures are generally dominated by the relation between the synchrotron cooling and the light-crossing timescale, which is largely independent ofmore » the exact model parameters. We find that unlike the low-energy polarization signatures, which can vary rapidly in time, the high-energy polarization signatures appear stable. Lastly, future high-energy polarimeters may be able to distinguish such signatures from the lower and more rapidly variable polarization signatures expected in leptonic models.« less
Radiation and polarization signatures of the 3D multizone time-dependent hadronic blazar model
Zhang, Haocheng; Diltz, Chris; Bottcher, Markus
2016-09-23
We present a newly developed time-dependent three-dimensional multizone hadronic blazar emission model. By coupling a Fokker–Planck-based lepto-hadronic particle evolution code, 3DHad, with a polarization-dependent radiation transfer code, 3DPol, we are able to study the time-dependent radiation and polarization signatures of a hadronic blazar model for the first time. Our current code is limited to parameter regimes in which the hadronic γ-ray output is dominated by proton synchrotron emission, neglecting pion production. Our results demonstrate that the time-dependent flux and polarization signatures are generally dominated by the relation between the synchrotron cooling and the light-crossing timescale, which is largely independent of the exact model parameters. We find that unlike the low-energy polarization signatures, which can vary rapidly in time, the high-energy polarization signatures appear stable. Lastly, future high-energy polarimeters may be able to distinguish such signatures from the lower and more rapidly variable polarization signatures expected in leptonic models.
Radiation and polarization signatures of the 3D multizone time-dependent hadronic blazar model
Zhang, Haocheng; Diltz, Chris; Bottcher, Markus
2016-09-23
We present a newly developed time-dependent three-dimensional multizone hadronic blazar emission model. By coupling a Fokker–Planck-based lepto-hadronic particle evolution code, 3DHad, with a polarization-dependent radiation transfer code, 3DPol, we are able to study the time-dependent radiation and polarization signatures of a hadronic blazar model for the first time. Our current code is limited to parameter regimes in which the hadronic γ-ray output is dominated by proton synchrotron emission, neglecting pion production. Our results demonstrate that the time-dependent flux and polarization signatures are generally dominated by the relation between the synchrotron cooling and the light-crossing timescale, which is largely independent of the exact model parameters. We find that unlike the low-energy polarization signatures, which can vary rapidly in time, the high-energy polarization signatures appear stable. Lastly, future high-energy polarimeters may be able to distinguish such signatures from the lower and more rapidly variable polarization signatures expected in leptonic models.
Time dependence of Fe/O ratio within a 3D solar energetic particle propagation model including drift
NASA Astrophysics Data System (ADS)
Dalla, S.; Marsh, M. S.; Zelina, P.; Laitinen, T.
2017-02-01
Context. The intensity profiles of iron and oxygen in Solar Energetic Particle (SEP) events often display differences that result in a decreasing Fe/O ratio over time. The physical mechanisms behind this behaviour are not fully understood, but these observational signatures provide important tests of physical modelling efforts. Aims: In this paper we study the propagation of iron and oxygen SEP ions using a 3D model of propagation which includes the effect of guiding centre drift in a Parker spiral magnetic field. We derive time intensity profiles for a variety of observer locations and study the temporal evolution of the Fe/O ratio. Methods: We use a 3D full orbit test particle model which includes scattering. The configuration of the interplanetary magnetic field is a unipolar Parker spiral. Particles are released instantaneously from a compact region at two solar radii and allowed to propagate in 3D. Results: Both Fe and O experience significant transport across the magnetic field due to gradient and curvature drifts. We find that Fe ions drift more than O ions due to their larger mass-to-charge ratio, so that an observer that is not magnetically well connected to the source region will observe Fe arriving before O, for particles within the same range in energy per nucleon. As a result, for the majority of observer locations, the Fe/O ratio displays a decrease in time. Conclusions: We conclude that propagation effects associated with drifts produce a decay over time of the Fe/O ratio, qualitatively reproducing that observed in SEP event profiles.
NASA Astrophysics Data System (ADS)
Taramón, Jorge M.; Rodríguez-González, Juan; Negredo, Ana M.; Billen, Magali I.
2015-09-01
Several mechanisms have been suggested for the formation of flat slabs including buoyant features on the subducting plate, trenchward motion and thermal or cratonic structure of the overriding plate. Analysis of episodes of flat subduction indicate that not all flat slabs can be attributed to only one of these mechanisms and it is likely that multiple mechanisms work together to create the necessary conditions for flat slab subduction. In this study we examine the role of localized regions of cratonic lithosphere in the overriding plate in the formation and evolution of flat slabs. We explicitly build on previous models, by using time-dependent simulations with three-dimensional variation in overriding plate structure. We find that there are two modes of flat subduction: permanent underplating occurs when the slab is more buoyant (shorter or younger), while transient flattening occurs when there is more negative buoyancy (longer or older slabs). Our models show how regions of the slab adjacent to the subcratonic flat portion continue to pull the slab into the mantle leading to highly contorted slab shapes with apparent slab gaps beneath the craton. These results show how the interpretation of seismic images of subduction zones can be complicated by the occurrence of either permanent or transient flattening of the slab, and how the signature of a recent flat slab episode may persist as the slab resumes normal subduction. Our models suggest that permanent underplating of slabs may preferentially occur below thick and cold lithosphere providing a built-in mechanism for regeneration of cratons.
Khaled, S.M.
2015-07-01
This work presents the Verification and testing both the neutronic and thermal-hydraulics response of the positive reactivity-initiated power excursion accidents in small light water research reactors. Some research reactors have to build its own severe accidents code system. In this sense, a 3D space-time-dependent neutron diffusion models with thermal hydraulic feedback have been introduced, compared and tested both experimentally at criticality 14-cent and theoretically up to 1.5 $ with a number of similar codes. The results shows that no expected core failure or moderator boiling. (author)
3D non-LTE time-dependent spectrum synthesis for type Ia supernovae
NASA Astrophysics Data System (ADS)
Kromer, M.; Sim, S. A.; Hillebrandt, W.
2009-09-01
Despite the importance of Type Ia supernovae as standard candles for cosmology and to the chemical evolution of the Universe, it is still not completely understood how these explosions take place and which are the progenitor systems. In this contribution we present a Monte Carlo code for modelling the time-dependent 3D radiative transfer problem in chemically inhomogeneous models of supernova ejecta. We avoid free parameters so that a direct comparison between synthetic spectra and light curves calculated from hydrodynamic explosion models and observations becomes feasible. Calculations for the well known W7 explosion model and first applications to multidimensional toy models are shown.
Advanced in Visualization of 3D Time-Dependent CFD Solutions
NASA Technical Reports Server (NTRS)
Lane, David A.; Lasinski, T. A. (Technical Monitor)
1995-01-01
Numerical simulations of complex 3D time-dependent (unsteady) flows are becoming increasingly feasible because of the progress in computing systems. Unfortunately, many existing flow visualization systems were developed for time-independent (steady) solutions and do not adequately depict solutions from unsteady flow simulations. Furthermore, most systems only handle one time step of the solutions individually and do not consider the time-dependent nature of the solutions. For example, instantaneous streamlines are computed by tracking the particles using one time step of the solution. However, for streaklines and timelines, particles need to be tracked through all time steps. Streaklines can reveal quite different information about the flow than those revealed by instantaneous streamlines. Comparisons of instantaneous streamlines with dynamic streaklines are shown. For a complex 3D flow simulation, it is common to generate a grid system with several millions of grid points and to have tens of thousands of time steps. The disk requirement for storing the flow data can easily be tens of gigabytes. Visualizing solutions of this magnitude is a challenging problem with today's computer hardware technology. Even interactive visualization of one time step of the flow data can be a problem for some existing flow visualization systems because of the size of the grid. Current approaches for visualizing complex 3D time-dependent CFD solutions are described. The flow visualization system developed at NASA Ames Research Center to compute time-dependent particle traces from unsteady CFD solutions is described. The system computes particle traces (streaklines) by integrating through the time steps. This system has been used by several NASA scientists to visualize their CFD time-dependent solutions. The flow visualization capabilities of this system are described, and visualization results are shown.
Continuous Galerkin methods for solving the time-dependent Maxwell equations in 3D geometries
NASA Astrophysics Data System (ADS)
Ciarlet, Patrick, Jr.; Jamelot, Erell
2007-09-01
A few years ago, Costabel and Dauge proposed a variational setting, which allows one to solve numerically the time-harmonic Maxwell equations in 3D geometries with the help of a continuous approximation of the electromagnetic field. In this paper, we investigate how their framework can be adapted to compute the solution to the time-dependent Maxwell equations. In addition, we propose some extensions, such as the introduction of a mixed variational setting and its discretization, to handle the constraint on the divergence of the field.
A novel time dependent gamma evaluation function for dynamic 2D and 3D dose distributions.
Podesta, Mark; Persoon, Lucas C G G; Verhaegen, Frank
2014-10-21
Modern external beam radiotherapy requires detailed verification and quality assurance so that confidence can be placed on both the delivery of a single treatment fraction and on the consistency of delivery throughout the treatment course. To verify dose distributions, a comparison between prediction and measurement must be made. Comparisons between two dose distributions are commonly performed using a Gamma evaluation which is a calculation of two quantities on a pixel by pixel basis; the dose difference, and the distance to agreement. By providing acceptance criteria (e.g. 3%, 3 mm), the function will find the most appropriate match within its two degrees of freedom. For complex dynamic treatments such as IMRT or VMAT it is important to verify the dose delivery in a time dependent manner and so a gamma evaluation that includes a degree of freedom in the time domain via a third parameter, time to agreement, is presented here. A C++ (mex) based gamma function was created that could be run on either CPU and GPU computing platforms that would allow a degree of freedom in the time domain. Simple test cases were created in both 2D and 3D comprising of simple geometrical shapes with well-defined boundaries varying over time. Changes of varying magnitude in either space or time were introduced and repeated gamma analyses were performed varying the criteria. A clinical VMAT case was also included, artificial air bubbles of varying size were introduced to a patient geometry, along with shifts of varying magnitude in treatment time. For all test cases where errors in distance, dose or time were introduced, the time dependent gamma evaluation could accurately highlight the errors.The time dependent gamma function presented here allows time to be included as a degree of freedom in gamma evaluations. The function allows for 2D and 3D data sets which are varying over time to be compared using appropriate criteria without penalising minor offsets of subsequent radiation fields
A novel time dependent gamma evaluation function for dynamic 2D and 3D dose distributions
NASA Astrophysics Data System (ADS)
Podesta, Mark; CGG Persoon, Lucas; Verhaegen, Frank
2014-10-01
Modern external beam radiotherapy requires detailed verification and quality assurance so that confidence can be placed on both the delivery of a single treatment fraction and on the consistency of delivery throughout the treatment course. To verify dose distributions, a comparison between prediction and measurement must be made. Comparisons between two dose distributions are commonly performed using a Gamma evaluation which is a calculation of two quantities on a pixel by pixel basis; the dose difference, and the distance to agreement. By providing acceptance criteria (e.g. 3%, 3 mm), the function will find the most appropriate match within its two degrees of freedom. For complex dynamic treatments such as IMRT or VMAT it is important to verify the dose delivery in a time dependent manner and so a gamma evaluation that includes a degree of freedom in the time domain via a third parameter, time to agreement, is presented here. A C++ (mex) based gamma function was created that could be run on either CPU and GPU computing platforms that would allow a degree of freedom in the time domain. Simple test cases were created in both 2D and 3D comprising of simple geometrical shapes with well-defined boundaries varying over time. Changes of varying magnitude in either space or time were introduced and repeated gamma analyses were performed varying the criteria. A clinical VMAT case was also included, artificial air bubbles of varying size were introduced to a patient geometry, along with shifts of varying magnitude in treatment time. For all test cases where errors in distance, dose or time were introduced, the time dependent gamma evaluation could accurately highlight the errors. The time dependent gamma function presented here allows time to be included as a degree of freedom in gamma evaluations. The function allows for 2D and 3D data sets which are varying over time to be compared using appropriate criteria without penalising minor offsets of subsequent radiation
A 3D moisture-stress FEM analysis for time dependent problems in timber structures
NASA Astrophysics Data System (ADS)
Fortino, Stefania; Mirianon, Florian; Toratti, Tomi
2009-11-01
This paper presents a 3D moisture-stress numerical analysis for timber structures under variable humidity and load conditions. An orthotropic viscoelastic-mechanosorptive material model is specialized on the basis of previous models. Both the constitutive model and the equations needed to describe the moisture flow across the structure are implemented into user subroutines of the Abaqus finite element code and a coupled moisture-stress analysis is performed for several types of mechanical loads and moisture changes. The presented computational approach is validated by analyzing some wood tests described in the literature and comparing the computational results with the reported experimental data.
3D viscous time dependent analysis of a slow moving landslide by finite elements
NASA Astrophysics Data System (ADS)
Bru, Guadalupe; Fernández-Merodo, Josè Antonio; García-Davalillo, Juan Carlos; Herrera, Gerardo
2017-04-01
A methodology to study the cinematic behavior in time and 3D effects of slow moving landslides is presented by its application to the Portalet landslide, located in the Spanish Central Pyrenees. The area is characterize by the presence of several complex landslides triggered by glacial retreat and developed in weathered Devonian and Carboniferous slate materials. In summer 2004, the toe of two paleolanslides was excavated in order to construct a parking area, which reactivated the preexistent rupture surfaces and generated a new and smaller roto-translational landslide of about 5·105m3. Works were paralyzed and the road A-136 connecting Spain and France was temporary closed. In 2006 stabilizing solutions were performed, although surface and deep monitoring data reveal that the landslide is currently active. In this work the cinematic behavior of the Portalet parking landslide has been reproduced since the excavation in 2004 until 2016 by an advanced 3D finite element model (FEM) analysis. A detailed 3D litho-stratigraphic geometry has been defined using the information available from previous works(1-3): real topography, geological profiles, ground water level and material properties. The first step has been a stability analysis using the shear stress reduction (SSR) technique to calibrate the value of the friction angle of the soil layer where the rupture surface develops. In this step the sensibility of the mesh size has been studied, as is a critical parameter. Secondly, stability analysis results have been verified by simulating the parking excavation with a static analysis using Mohr-Coulomb elastoplastic failure criteria. In the last step the behavior of the landslide has been recreated using a hydromechanic coupled formulation for displacements and interstitial water pressure (u-pw), a simple elevation ground water model calculated from daily rainfall and a Perzyna viscous constitutive model of the solid skeleton which represent the creep detected by
Time-dependent oral absorption models
NASA Technical Reports Server (NTRS)
Higaki, K.; Yamashita, S.; Amidon, G. L.
2001-01-01
The plasma concentration-time profiles following oral administration of drugs are often irregular and cannot be interpreted easily with conventional models based on first- or zero-order absorption kinetics and lag time. Six new models were developed using a time-dependent absorption rate coefficient, ka(t), wherein the time dependency was varied to account for the dynamic processes such as changes in fluid absorption or secretion, in absorption surface area, and in motility with time, in the gastrointestinal tract. In the present study, the plasma concentration profiles of propranolol obtained in human subjects following oral dosing were analyzed using the newly derived models based on mass balance and compared with the conventional models. Nonlinear regression analysis indicated that the conventional compartment model including lag time (CLAG model) could not predict the rapid initial increase in plasma concentration after dosing and the predicted Cmax values were much lower than that observed. On the other hand, all models with the time-dependent absorption rate coefficient, ka(t), were superior to the CLAG model in predicting plasma concentration profiles. Based on Akaike's Information Criterion (AIC), the fluid absorption model without lag time (FA model) exhibited the best overall fit to the data. The two-phase model including lag time, TPLAG model was also found to be a good model judging from the values of sum of squares. This model also described the irregular profiles of plasma concentration with time and frequently predicted Cmax values satisfactorily. A comparison of the absorption rate profiles also suggested that the TPLAG model is better at prediction of irregular absorption kinetics than the FA model. In conclusion, the incorporation of a time-dependent absorption rate coefficient ka(t) allows the prediction of nonlinear absorption characteristics in a more reliable manner.
Time-dependent oral absorption models
NASA Technical Reports Server (NTRS)
Higaki, K.; Yamashita, S.; Amidon, G. L.
2001-01-01
The plasma concentration-time profiles following oral administration of drugs are often irregular and cannot be interpreted easily with conventional models based on first- or zero-order absorption kinetics and lag time. Six new models were developed using a time-dependent absorption rate coefficient, ka(t), wherein the time dependency was varied to account for the dynamic processes such as changes in fluid absorption or secretion, in absorption surface area, and in motility with time, in the gastrointestinal tract. In the present study, the plasma concentration profiles of propranolol obtained in human subjects following oral dosing were analyzed using the newly derived models based on mass balance and compared with the conventional models. Nonlinear regression analysis indicated that the conventional compartment model including lag time (CLAG model) could not predict the rapid initial increase in plasma concentration after dosing and the predicted Cmax values were much lower than that observed. On the other hand, all models with the time-dependent absorption rate coefficient, ka(t), were superior to the CLAG model in predicting plasma concentration profiles. Based on Akaike's Information Criterion (AIC), the fluid absorption model without lag time (FA model) exhibited the best overall fit to the data. The two-phase model including lag time, TPLAG model was also found to be a good model judging from the values of sum of squares. This model also described the irregular profiles of plasma concentration with time and frequently predicted Cmax values satisfactorily. A comparison of the absorption rate profiles also suggested that the TPLAG model is better at prediction of irregular absorption kinetics than the FA model. In conclusion, the incorporation of a time-dependent absorption rate coefficient ka(t) allows the prediction of nonlinear absorption characteristics in a more reliable manner.
Time-dependent freezing rate parcel model
NASA Astrophysics Data System (ADS)
Vali, G.; Snider, J. R.
2015-02-01
The time-dependent freezing rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period in time when the parcel remains stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experiments with cloud and precipitation samples and is assumed to represent the INP content of the cloud droplets in the parcel. Time dependence is included to account for variations in updraft velocity and for the continued formation of ice particles under isothermal conditions. The magnitudes of these factors are assessed on the basis of laboratory measurements. Results show that both factors give rise to three-fold variations in ice concentration for a realistic range of the input parameters. Refinements of the parameters specifying time dependence and INP concentrations are needed to make the results more specific to different atmospheric aerosol types. The simple model framework described in this paper can be adapted to more elaborate cloud models. The results here presented can help guide decisions on whether to include a time-dependent ice nucleation scheme or a simpler singular description in models.
Time-dependent freezing rate parcel model
NASA Astrophysics Data System (ADS)
Vali, G.; Snider, J. R.
2014-11-01
The Time-Dependent Freezing Rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period at time with the parcel remaining stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experiments with cloud and precipitation samples and is assumed to represent the INP content of the cloud droplets in the parcel. Time-dependence is included to account for variations in updraft velocity and for the continued formation of ice particles at isothermal conditions. The magnitudes of these factors are assessed on the basis of laboratory measurements. Results show that both factors give rise to factors of about 3 variations in ice concentration for a realistic range of the input parameters. Refinements of the parameters specifying time-dependence and INP concentrations are needed to make the results more specific to different atmospheric aerosol types. The simple model framework described in this paper can be adapted to more elaborate cloud models. The results here presented can help guide decisions on whether to include a time-dependent ice nucleation scheme or a simpler singular description in models.
NASA Astrophysics Data System (ADS)
Obermann, Anne; Planès, Thomas; Hadziioannou, Céline; Campillo, Michel
2016-10-01
In the context of seismic monitoring, recent studies made successful use of seismic coda waves to locate medium changes on the horizontal plane. Locating the depth of the changes, however, remains a challenge. In this paper, we use 3-D wavefield simulations to address two problems: first, we evaluate the contribution of surface- and body-wave sensitivity to a change at depth. We introduce a thin layer with a perturbed velocity at different depths and measure the apparent relative velocity changes due to this layer at different times in the coda and for different degrees of heterogeneity of the model. We show that the depth sensitivity can be modelled as a linear combination of body- and surface-wave sensitivity. The lapse-time-dependent sensitivity ratio of body waves and surface waves can be used to build 3-D sensitivity kernels for imaging purposes. Second, we compare the lapse-time behaviour in the presence of a perturbation in horizontal and vertical slabs to address, for instance, the origin of the velocity changes detected after large earthquakes.
This collaborative grant is developing 3D models of both mouse and human biology to investigate aspects of therapeutic vaccination in order to answer key questions relevant to human cancer immunotherapy.
NASA Astrophysics Data System (ADS)
Regnier, D.; Dubray, N.; Schunck, N.; Verrière, M.
2017-09-01
Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r-process to fuel cycle optimization in nuclear energy. The need for a predictive theory applicable where no data is available, together with the variety of potential applications, is an incentive to develop a fully microscopic approach to fission dynamics. One of the most promising theoretical frameworks is the time dependent generator coordinate method (TDGCM) applied under the Gaussian overlap approximation (GOA). However, the computational cost of this method makes it difficult to perform calculations with more than two collective degree of freedom. Meanwhile, it is well-known from both semi-phenomenological and fully microscopic approaches that at least four or five dimensions may play a role in the dynamics of fission. To overcome this limitation, we develop the code FELIX aiming to solve the TDGCM+GOA equation for an arbitrary number of collective variables. In this talk, we report the recent progress toward this enriched description of fission dynamics. We will briefly present the numerical methods adopted as well as the status of the latest version of FELIX. Finally, we will discuss fragments yields obtained within this approach for the low energy fission of major actinides.
ERIC Educational Resources Information Center
Manos, Harry
2016-01-01
Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…
ERIC Educational Resources Information Center
Manos, Harry
2016-01-01
Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…
Time-dependent Hartree approximation and time-dependent harmonic oscillator model
NASA Astrophysics Data System (ADS)
Blaizot, J. P.; Schulz, H.
1982-03-01
We present an analytically soluble model for studying nuclear collective motion within the framework of the time-dependent Hartree (TDH) approximation. The model reduces the TDH equations to the Schrödinger equation of a time-dependent harmonic oscillator. Using canonical transformations and coherent states we derive a few properties of the time-dependent harmonic oscillator which are relevant for applications. We analyse the role of the normal modes in the time evolution of a system governed by TDH equations. We show how these modes couple together due to the anharmonic terms generated by the non-linearity of the theory.
JHelioviewer. Time-dependent 3D visualisation of solar and heliospheric data
NASA Astrophysics Data System (ADS)
Müller, D.; Nicula, B.; Felix, S.; Verstringe, F.; Bourgoignie, B.; Csillaghy, A.; Berghmans, D.; Jiggens, P.; García-Ortiz, J. P.; Ireland, J.; Zahniy, S.; Fleck, B.
2017-09-01
offers a virtual camera model that enables users to set the vantage point to the location of a spacecraft or celestial body at any given time.
Time-dependent Flare Models with MALI
NASA Astrophysics Data System (ADS)
Kašparová, J.; Heinzel, P.; Varady, M.; Karlický, M.
2003-01-01
Temporal variations of Hα line profile intensities related to electron beams are presented. We show first results of time dependent simulations of a chromospheric response to a 1 sec monoenergetic electron beam. 1-D hydrodynamic code together with particle representation of the beam have been used to calculate atmospheric evolution. Time dependent radiative transfer problem has been solved for the resulting atmosphere in the MALI approach, using the Crank-Nicholson implicit scheme. Non-thermal collisional rates were included in linearised equations of statistical equilibrium.
NASA Astrophysics Data System (ADS)
Manos, Harry
2016-03-01
Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.
NASA Astrophysics Data System (ADS)
Chen, Yu; Xie, Xilin
2016-05-01
E and Liu [J. Comput. Phys. 138 (1997) 57-82] put forward a finite difference method for 3D viscous incompressible flows in the vorticity-vector potential formulation on non-staggered grids. In this paper, we will extend this method to the case of flows in the presence of a deformable surface. By use of two kinds of surface differential operators, the implementation of boundary conditions on a plane is generalized to a curved smooth surface with given velocity distribution, whether this be an inflow/outflow interface or a curved wall. To deal with the irregular and varying physical domain, time-dependent curvilinear coordinates are constructed and the corresponding tensor analysis is adopted in deriving the component form of the governing equations. Therefore, the equations can be discretized and solved in a regular and fixed parametric domain. Numerical results are presented for a 3D lid-driven cavity with a deforming surface and a 3D duct flow with a deforming boundary. A new way to validate numerical simulations is proposed based on an expression for the rate-of-strain tensor on a deformable surface.
Crowdsourcing Based 3d Modeling
NASA Astrophysics Data System (ADS)
Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.
2016-06-01
Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.
NASA Astrophysics Data System (ADS)
Gainullin, I. K.; Sonkin, M. A.
2015-03-01
A parallelized three-dimensional (3D) time-dependent Schrodinger equation (TDSE) solver for one-electron systems is presented in this paper. The TDSE Solver is based on the finite-difference method (FDM) in Cartesian coordinates and uses a simple and explicit leap-frog numerical scheme. The simplicity of the numerical method provides very efficient parallelization and high performance of calculations using Graphics Processing Units (GPUs). For example, calculation of 106 time-steps on the 1000ṡ1000ṡ1000 numerical grid (109 points) takes only 16 hours on 16 Tesla M2090 GPUs. The TDSE Solver demonstrates scalability (parallel efficiency) close to 100% with some limitations on the problem size. The TDSE Solver is validated by calculation of energy eigenstates of the hydrogen atom (13.55 eV) and affinity level of H- ion (0.75 eV). The comparison with other TDSE solvers shows that a GPU-based TDSE Solver is 3 times faster for the problems of the same size and with the same cost of computational resources. The usage of a non-regular Cartesian grid or problem-specific non-Cartesian coordinates increases this benefit up to 10 times. The TDSE Solver was applied to the calculation of the resonant charge transfer (RCT) in nanosystems, including several related physical problems, such as electron capture during H+-H0 collision and electron tunneling between H- ion and thin metallic island film.
3D Printing of Molecular Models
ERIC Educational Resources Information Center
Gardner, Adam; Olson, Arthur
2016-01-01
Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…
3D Printing of Molecular Models
ERIC Educational Resources Information Center
Gardner, Adam; Olson, Arthur
2016-01-01
Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…
NASA Astrophysics Data System (ADS)
Zawdie, K. A.; Drob, D. P.; Huba, J. D.; Coker, C.
2016-07-01
One of the challenges for the utilization of HF radiowaves in practical applications is to understand how the signals propagate in time- and range-dependent multipath environments. For typical quiescent ionospheric conditions it is often reasonably straightforward to interpret received HF signals. For disturbed ionospheric conditions, however, such as in the presence of large tilts, irregularities, and medium-scale traveling ionospheric disturbances (MSTIDs), data interpretation and utilization often becomes challenging. This paper presents a theoretical HF propagation modeling study that exploits the capabilities of a first principles, mesoscale resolution ionosphere code, SAMI3 (Sami3 is Another Model of the Ionosphere) and a new implementation of the 3-D ray trace equations, MoJo-15 (Modernized Jones Code) in order to examine the relationship between various HF propagation observables and MSTID characteristics. This paper demonstrates the implications of MSTIDS on high angle of incidence HF propagation during typical low-latitude, postsunset ionospheric conditions and examines the spatiotemporal evolution of multiple propagation paths that may connect a given source and receiver.
BEAMS3D Neutral Beam Injection Model
Lazerson, Samuel
2014-04-14
With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.
Modeling cellular processes in 3D.
Mogilner, Alex; Odde, David
2011-12-01
Recent advances in photonic imaging and fluorescent protein technology offer unprecedented views of molecular space-time dynamics in living cells. At the same time, advances in computing hardware and software enable modeling of ever more complex systems, from global climate to cell division. As modeling and experiment become more closely integrated we must address the issue of modeling cellular processes in 3D. Here, we highlight recent advances related to 3D modeling in cell biology. While some processes require full 3D analysis, we suggest that others are more naturally described in 2D or 1D. Keeping the dimensionality as low as possible reduces computational time and makes models more intuitively comprehensible; however, the ability to test full 3D models will build greater confidence in models generally and remains an important emerging area of cell biological modeling. Copyright © 2011 Elsevier Ltd. All rights reserved.
Modeling Cellular Processes in 3-D
Mogilner, Alex; Odde, David
2011-01-01
Summary Recent advances in photonic imaging and fluorescent protein technology offer unprecedented views of molecular space-time dynamics in living cells. At the same time, advances in computing hardware and software enable modeling of ever more complex systems, from global climate to cell division. As modeling and experiment become more closely integrated, we must address the issue of modeling cellular processes in 3-D. Here, we highlight recent advances related to 3-D modeling in cell biology. While some processes require full 3-D analysis, we suggest that others are more naturally described in 2-D or 1-D. Keeping the dimensionality as low as possible reduces computational time and makes models more intuitively comprehensible; however, the ability to test full 3-D models will build greater confidence in models generally and remains an important emerging area of cell biological modeling. PMID:22036197
RHOCUBE: 3D density distributions modeling code
NASA Astrophysics Data System (ADS)
Nikutta, Robert; Agliozzo, Claudia
2016-11-01
RHOCUBE models 3D density distributions on a discrete Cartesian grid and their integrated 2D maps. It can be used for a range of applications, including modeling the electron number density in LBV shells and computing the emission measure. The RHOCUBE Python package provides several 3D density distributions, including a powerlaw shell, truncated Gaussian shell, constant-density torus, dual cones, and spiralling helical tubes, and can accept additional distributions. RHOCUBE provides convenient methods for shifts and rotations in 3D, and if necessary, an arbitrary number of density distributions can be combined into the same model cube and the integration ∫ dz performed through the joint density field.
2009-01-01
phase matrix were determined by letting the elements of the reduced phase matrix ( ˜ P ij = Pij /P11) be equal to those of the reduced Rayleigh...for the solution of 3-D Radiative Transfer Problems”, JQSRT. 45. 47-56, (1991) 3. A. Sánchez, T.F. Smith, and W. F. Krajewski “A three-dimensional...F. Krajewski , “A Multi-dimensional Discrete Ordinates Method for Polarized Radiative Transfer, Part I: Validation for Randomly Oriented
2013-09-30
vector Monte Carlo code to calculate what is known as SOES (Spatial Offset Elastic Scattering ). We have used our method to calculate the SOES signal... scattering properties, such as different single scattering albedo, different phase function and different phase matrix. Our new 3D vector Monte Carlo ...feature about the asymptotic light field is that it depends profoundly on both the single scattering albedo as well as the phase function of the medium
A Hybrid 3D Indoor Space Model
NASA Astrophysics Data System (ADS)
Jamali, Ali; Rahman, Alias Abdul; Boguslawski, Pawel
2016-10-01
GIS integrates spatial information and spatial analysis. An important example of such integration is for emergency response which requires route planning inside and outside of a building. Route planning requires detailed information related to indoor and outdoor environment. Indoor navigation network models including Geometric Network Model (GNM), Navigable Space Model, sub-division model and regular-grid model lack indoor data sources and abstraction methods. In this paper, a hybrid indoor space model is proposed. In the proposed method, 3D modeling of indoor navigation network is based on surveying control points and it is less dependent on the 3D geometrical building model. This research proposes a method of indoor space modeling for the buildings which do not have proper 2D/3D geometrical models or they lack semantic or topological information. The proposed hybrid model consists of topological, geometrical and semantical space.
NASA Technical Reports Server (NTRS)
Aftosmis, M. J.; Berger, M. J.; Murman, S. M.; Kwak, Dochan (Technical Monitor)
2002-01-01
The proposed paper will present recent extensions in the development of an efficient Euler solver for adaptively-refined Cartesian meshes with embedded boundaries. The paper will focus on extensions of the basic method to include solution adaptation, time-dependent flow simulation, and arbitrary rigid domain motion. The parallel multilevel method makes use of on-the-fly parallel domain decomposition to achieve extremely good scalability on large numbers of processors, and is coupled with an automatic coarse mesh generation algorithm for efficient processing by a multigrid smoother. Numerical results are presented demonstrating parallel speed-ups of up to 435 on 512 processors. Solution-based adaptation may be keyed off truncation error estimates using tau-extrapolation or a variety of feature detection based refinement parameters. The multigrid method is extended to for time-dependent flows through the use of a dual-time approach. The extension to rigid domain motion uses an Arbitrary Lagrangian-Eulerlarian (ALE) formulation, and results will be presented for a variety of two- and three-dimensional example problems with both simple and complex geometry.
NUBEAM developments and 3d halo modeling
NASA Astrophysics Data System (ADS)
Gorelenkova, M. V.; Medley, S. S.; Kaye, S. M.
2012-10-01
Recent developments related to the 3D halo model in NUBEAM code are described. To have a reliable halo neutral source for diagnostic simulation, the TRANSP/NUBEAM code has been enhanced with full implementation of ADAS atomic physic ground state and excited state data for hydrogenic beams and mixed species plasma targets. The ADAS codes and database provide the density and temperature dependence of the atomic data, and the collective nature of the state excitation process. To be able to populate 3D halo output with sufficient statistical resolution, the capability to control the statistics of fast ion CX modeling and for thermal halo launch has been added to NUBEAM. The 3D halo neutral model is based on modification and extension of the ``beam in box'' aligned 3d Cartesian grid that includes the neutral beam itself, 3D fast neutral densities due to CX of partially slowed down fast ions in the beam halo region, 3D thermal neutral densities due to CX deposition and fast neutral recapture source. More details on the 3D halo simulation design will be presented.
3D PMN Flextensional Stave Modeling
2000-04-13
WEIDLINGER ASSOCIATES, INC. 3D PMN Flextensional Stave Modeling** Greg Wojcik, John Mould, Paul Reynolds, Roger Richards* Weidlinger Associates Inc...2000 4. TITLE AND SUBTITLE 3D PMN Flextensional Stave Modeling 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...broadband • To address general needs of Navy Consider PMN-driven projector • Staves of butted Class IV flextensional shells • Array composed of
2007-09-30
An efficient method for the solution of 3-D Radiative Transfer Problems”, JQSRT. 45. 47-56, (1991) 3. A. Sánchez, T.F. Smith, and W. F. Krajewski ...Haferman, T. F. Smith, and W. F. Krajewski , “A Multi-dimensional Discrete Ordinates Method for Polarized Radiative Transfer, Part I: Validation for...Operator Theory of Radiative Transfer. II. Scattering from Maritime Haze,” Appl. Opt. l2, 1071-1084 (1973). PUBLICATIONS 1. P . Zhai, G. W. Kattawar
Cullen, D.E
2000-11-22
TART2000 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input Preparation, running Monte Carlo calculations, and analysis of output results. TART2000 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART2000 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART2000 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART2000 and its data files.
Cullen, D E
1998-11-22
TART98 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART98 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART98 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART98 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART98 and its data files.
Gamma time-dependency in Blaxter's compartmental model.
NASA Technical Reports Server (NTRS)
Matis, J. H.
1972-01-01
A new two-compartment model for the passage of particles through the gastro-intestinal tract of ruminants is proposed. In this model, a gamma distribution of lifetimes is introduced in the first compartment; thereby, passage from that compartment becomes time-dependent. This modification is strongly suggested by the physical alteration which certain substances, e.g. hay particles, undergo in the digestive process. The proposed model is applied to experimental data.
Time Dependent Models of Grain Formation Around Carbon Stars
NASA Technical Reports Server (NTRS)
Egan, M. P.; Shipman, R. F.
1996-01-01
Carbon-rich Asymptotic Giant Branch stars are sites of dust formation and undergo mass loss at rates ranging from 10(exp -7) to 10(exp -4) solar mass/yr. The state-of-the-art in modeling these processes is time-dependent models which simultaneously solve the grain formation and gas dynamics problem. We present results from such a model, which also includes an exact solution of the radiative transfer within the system.
Statistical time-dependent model for the interstellar gas
NASA Technical Reports Server (NTRS)
Gerola, H.; Kafatos, M.; Mccray, R.
1974-01-01
We present models for temperature and ionization structure of low, uniform-density (approximately 0.3 per cu cm) interstellar gas in a galactic disk which is exposed to soft X rays from supernova outbursts occurring randomly in space and time. The structure was calculated by computing the time record of temperature and ionization at a given point by Monte Carlo simulation. The calculation yields probability distribution functions for ionized fraction, temperature, and their various observable moments. These time-dependent models predict a bimodal temperature distribution of the gas that agrees with various observations. Cold regions in the low-density gas may have the appearance of clouds in 21-cm absorption. The time-dependent model, in contrast to the steady-state model, predicts large fluctuations in ionization rate and the existence of cold (approximately 30 K), ionized (ionized fraction equal to about 0.1) regions.
Time-dependent buoyant puff model for explosive sources
Kansa, E.J.
1997-01-01
Several models exist to predict the time dependent behavior of bouyant puffs that result from explosions. This paper presents a new model 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 model permits the cloud to evolve from an intial spherical shape not an ellipsoidal shape. It ignores the Boussinesq 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 puff 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 model was calibrated by comparison with the Roller Coaster experiments.
Statistical time-dependent model for the interstellar gas
NASA Technical Reports Server (NTRS)
Gerola, H.; Kafatos, M.; Mccray, R.
1974-01-01
We present models for temperature and ionization structure of low, uniform-density (approximately 0.3 per cu cm) interstellar gas in a galactic disk which is exposed to soft X rays from supernova outbursts occurring randomly in space and time. The structure was calculated by computing the time record of temperature and ionization at a given point by Monte Carlo simulation. The calculation yields probability distribution functions for ionized fraction, temperature, and their various observable moments. These time-dependent models predict a bimodal temperature distribution of the gas that agrees with various observations. Cold regions in the low-density gas may have the appearance of clouds in 21-cm absorption. The time-dependent model, in contrast to the steady-state model, predicts large fluctuations in ionization rate and the existence of cold (approximately 30 K), ionized (ionized fraction equal to about 0.1) regions.
Resist loss in 3D compact modeling
NASA Astrophysics Data System (ADS)
Zheng, Xin; Huang, Jensheng; Chin, Fook; Kazarian, Aram; Kuo, Chun-Chieh
2012-03-01
An enhancement to compact modeling capability to include photoresist (PR) loss at different heights is developed and discussed. A hypsometric map representing 3-D resist profile was built by applying a first principle approximation to estimate the "energy loss" from the resist top to any other plane of interest as a proportional corresponding change in model threshold, which is analogous to a change in exposure dose. The result is compared and validated with 3D rigorous modeling as well as SEM images. Without increase in computation time, this compact model can construct 3D resist profiles capturing resist profile degradation at any vertical plane. Sidewall angle and standing wave information can also be granted from the vertical profile reconstruction. Since this method does not change any form of compact modeling, it can be integrated to validation and correction without any additional work.
Chromospheric extents predicted by time-dependent acoustic wave models
NASA Astrophysics Data System (ADS)
Cuntz, Manfred
1990-01-01
Theoretical models for chromospheric structures of late-type giant stars are computed, including the time-dependent propagation of acoustic waves. Models with short-period monochromatic shock waves as well as a spectrum of acoustic waves are discussed, and the method is applied to the stars Arcturus, Aldebaran, and Betelgeuse. Chromospheric extent, defined as the monotonic decrease with height of the time-averaged electron densities, are found to be 1.12, 1.13, and 1.22 stellar radii for the three stars, respectively; this corresponds to a time-averaged electron density of 10 to the 7th/cu cm. Predictions of the extended chromospheric obtained using a simple scaling law agree well with those obtained by the time-dependent wave models; thus, the chromospheres of all stars for which the scaling law is valid consist of the same number of pressure scale heights.
Chromospheric extents predicted by time-dependent acoustic wave models
Cuntz, M. Heidelberg Universitaet )
1990-01-01
Theoretical models for chromospheric structures of late-type giant stars are computed, including the time-dependent propagation of acoustic waves. Models with short-period monochromatic shock waves as well as a spectrum of acoustic waves are discussed, and the method is applied to the stars Arcturus, Aldebaran, and Betelgeuse. Chromospheric extent, defined as the monotonic decrease with height of the time-averaged electron densities, are found to be 1.12, 1.13, and 1.22 stellar radii for the three stars, respectively; this corresponds to a time-averaged electron density of 10 to the 7th/cu cm. Predictions of the extended chromospheric obtained using a simple scaling law agree well with those obtained by the time-dependent wave models; thus, the chromospheres of all stars for which the scaling law is valid consist of the same number of pressure scale heights. 74 refs.
3D Modeling Engine Representation Summary Report
Steven Prescott; Ramprasad Sampath; Curtis Smith; Timothy Yang
2014-09-01
Computers have been used for 3D modeling and simulation, but only recently have computational resources been able to give realistic results in a reasonable time frame for large complex models. This summary report addressed the methods, techniques, and resources used to develop a 3D modeling engine to represent risk analysis simulation for advanced small modular reactor structures and components. The simulations done for this evaluation were focused on external events, specifically tsunami floods, for a hypothetical nuclear power facility on a coastline.
Multifractal modelling and 3D lacunarity analysis
NASA Astrophysics Data System (ADS)
Hanen, Akkari; Imen, Bhouri; Asma, Ben Abdallah; Patrick, Dubois; Hédi, Bedoui Mohamed
2009-09-01
This study presents a comparative evaluation of lacunarity of 3D grey level models with different types of inhomogeneity. A new method based on the “Relative Differential Box Counting” was developed to estimate the lacunarity features of grey level volumes. To validate our method, we generated a set of 3D grey level multifractal models with random, anisotropic and hierarchical properties. Our method gives a lacunarity measurement correlated with the theoretical one and allows a better model classification compared with a classical approach.
BEAMS3D Neutral Beam Injection Model
NASA Astrophysics Data System (ADS)
McMillan, Matthew; Lazerson, Samuel A.
2014-09-01
With the advent of applied 3D fields in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous slowing down, and pitch angle scattering are modeled with the ADAS atomic physics database. Elementary benchmark calculations are presented to verify the collisionless particle orbits, NBI model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields. Notice: this manuscript has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.
Time dependent modeling of non-LTE plasmas: Final report
Not Available
1988-06-01
During the period of performance of this contract Science Applications International Corporation (SAIC) has aided Lawrence Livermore National Laboratory (LLNL) in the development of an unclassified modeling tool for studying time evolution of high temperature ionizing and recombining plasmas. This report covers the numerical code developed, (D)ynamic (D)etailed (C)onfiguration (A)ccounting (DDCA), which was written to run on the National Magnetic Fusion Energy Computing Center (NMFECC) network as well as the classified Livermore Computer Center (OCTOPUS) network. DDCA is a One-Dimensional (1D) time dependent hydrodynamic model which makes use of the non-LTE detailed atomic physics ionization model DCA. 5 refs.
Solvable time-dependent models in quantum mechanics
NASA Astrophysics Data System (ADS)
Cordero-Soto, Ricardo J.
In the traditional setting of quantum mechanics, the Hamiltonian operator does not depend on time. While some Schrodinger equations with time-dependent Hamiltonians have been solved, explicitly solvable cases are typically scarce. This thesis is a collection of papers in which this first author along with Suslov, Suazo, and Lopez, has worked on solving a series of Schrodinger equations with a time-dependent quadratic Hamiltonian that has applications in problems of quantum electrodynamics, lasers, quantum devices such as quantum dots, and external varying fields. In particular the author discusses a new completely integrable case of the time-dependent Schrodinger equation in Rn with variable coefficients for a modified oscillator, which is dual with respect to the time inversion to a model of the quantum oscillator considered by Meiler, Cordero-Soto, and Suslov. A second pair of dual Hamiltonians is found in the momentum representation. Our examples show that in mathematical physics and quantum mechanics a change in the direction of time may require a total change of the system dynamics in order to return the system back to its original quantum state. The author also considers several models of the damped oscillators in nonrelativistic quantum mechanics in a framework of a general approach to the dynamics of the time-dependent Schrodinger equation with variable quadratic Hamiltonians. The Green functions are explicitly found in terms of elementary functions and the corresponding gauge transformations are discussed. The factorization technique is applied to the case of a shifted harmonic oscillator. The time-evolution of the expectation values of the energy related operators is determined for two models of the quantum damped oscillators under consideration. The classical equations of motion for the damped oscillations are derived for the corresponding expectation values of the position operator. Finally, the author constructs integrals of motion for several models
2010-01-01
RaDyO platforms, the R/ P FLoating Instrument Platform (FLIP) and the R/V Kilo Moana (KM), are usually different. Among other important results, it is... Krajewski “A three-dimensional atmospheric radiative transfer model based on the discrete ordinates method”, Atmos. Res. 33, 283-308, (1994), 4. J. L...Haferman, T. F. Smith, and W. F. Krajewski , “A Multi-dimensional Discrete Ordinates Method for Polarized Radiative Transfer, Part I: Validation for
ERIC Educational Resources Information Center
Bradley, Joan; Farland-Smith, Donna
2010-01-01
Allowing a student to "see" through touch what other students see through a microscope can be a challenging task. Therefore, author Joan Bradley created three-dimensional (3-D) models with one student's visual impairment in mind. They are meant to benefit all students and can be used to teach common high school biology topics, including the…
Constructing Arguments with 3-D Printed Models
ERIC Educational Resources Information Center
McConnell, William; Dickerson, Daniel
2017-01-01
In this article, the authors describe a fourth-grade lesson where 3-D printing technologies were not only a stimulus for engagement but also served as a modeling tool providing meaningful learning opportunities. Specifically, fourth-grade students construct an argument that animals' external structures function to support survival in a particular…
Constructing Arguments with 3-D Printed Models
ERIC Educational Resources Information Center
McConnell, William; Dickerson, Daniel
2017-01-01
In this article, the authors describe a fourth-grade lesson where 3-D printing technologies were not only a stimulus for engagement but also served as a modeling tool providing meaningful learning opportunities. Specifically, fourth-grade students construct an argument that animals' external structures function to support survival in a particular…
ERIC Educational Resources Information Center
Bradley, Joan; Farland-Smith, Donna
2010-01-01
Allowing a student to "see" through touch what other students see through a microscope can be a challenging task. Therefore, author Joan Bradley created three-dimensional (3-D) models with one student's visual impairment in mind. They are meant to benefit all students and can be used to teach common high school biology topics, including the…
2011-09-30
1 m 440 nm (b) 488 nm (c) 0.0 0.2 0.4 0.6 0.8 1.0 510 nm D oL P (d) 532 nm (e) 555 nm (f) -90 -45 0 45 90 135 0.0 0.2 0.4 0.6 0.8 1.0 650 nm (g) -90...1 m 440 nm (b) 488 nm (c) -90 -45 0 45 90 510 nm A oL P (d) 532 nm (e) 555 nm (f) -90 -45 0 45 90 135 -90 -45 0 45 90 650 nm (g) -90 -45 0 45 90 135...47-56, (1991) 3. A. Sánchez, T.F. Smith, and W. F. Krajewski “A three-dimensional atmospheric radiative transfer model based on the discrete
TIME-DEPENDENT MODELS OF FLARES FROM SAGITTARIUS A*
Dodds-Eden, Katie; Genzel, Reinhard; Gillessen, Stefan; Eisenhauer, Frank; Sharma, Prateek; Quataert, Eliot; Porquet, Delphine
2010-12-10
The emission from Sgr A*, the supermassive black hole in the Galactic Center, shows order of magnitude variability ('flares') a few times a day that is particularly prominent in the near-infrared (NIR) and X-rays. We present a time-dependent model for these flares motivated by the hypothesis that dissipation of magnetic energy powers the flares. We show that episodic magnetic reconnection can occur near the last stable circular orbit in time-dependent magnetohydrodynamic simulations of black hole accretion-the timescales and energetics of these events are broadly consistent with the flares from Sgr A*. Motivated by these results, we present a spatially one-zone time-dependent model for the electron distribution function in flares, including energy loss due to synchrotron cooling and adiabatic expansion. Synchrotron emission from transiently accelerated particles can explain the NIR/X-ray light curves and spectra of a luminous flare observed on 2007 April 4. A significant decrease in the magnetic field strength during the flare (coincident with the electron acceleration) is required to explain the simultaneity and symmetry of the simultaneous light curves. Our models predict that the NIR and X-ray spectral indices are related by {Delta}{alpha} {approx_equal} 0.5 (where {nu}F{sub {nu}} {proportional_to} {nu}{sup {alpha}}) and that there is only modest variation in the spectral index during flares. We also explore implications of this model for longer wavelength (radio-submillimeter) emission seemingly associated with X-ray and NIR flares; we argue that a few hour decrease in the submillimeter emission is a more generic consequence of large-scale magnetic reconnection than delayed radio emission from adiabatic expansion.
Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing
ERIC Educational Resources Information Center
Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.
2016-01-01
Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…
Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing
ERIC Educational Resources Information Center
Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.
2016-01-01
Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…
Debris Dispersion Model Using Java 3D
NASA Technical Reports Server (NTRS)
Thirumalainambi, Rajkumar; Bardina, Jorge
2004-01-01
This paper describes web based simulation of Shuttle launch operations and debris dispersion. Java 3D graphics provides geometric and visual content with suitable mathematical model and behaviors of Shuttle launch. Because the model is so heterogeneous and interrelated with various factors, 3D graphics combined with physical models provides mechanisms to understand the complexity of launch and range operations. The main focus in the modeling and simulation covers orbital dynamics and range safety. Range safety areas include destruct limit lines, telemetry and tracking and population risk near range. If there is an explosion of Shuttle during launch, debris dispersion is explained. The shuttle launch and range operations in this paper are discussed based on the operations from Kennedy Space Center, Florida, USA.
Time dependent patient no-show predictive modelling development.
Huang, Yu-Li; Hanauer, David A
2016-05-09
Purpose - The purpose of this paper is to develop evident-based predictive no-show models considering patients' each past appointment status, a time-dependent component, as an independent predictor to improve predictability. Design/methodology/approach - A ten-year retrospective data set was extracted from a pediatric clinic. It consisted of 7,291 distinct patients who had at least two visits along with their appointment characteristics, patient demographics, and insurance information. Logistic regression was adopted to develop no-show models using two-thirds of the data for training and the remaining data for validation. The no-show threshold was then determined based on minimizing the misclassification of show/no-show assignments. There were a total of 26 predictive model developed based on the number of available past appointments. Simulation was employed to test the effective of each model on costs of patient wait time, physician idle time, and overtime. Findings - The results demonstrated the misclassification rate and the area under the curve of the receiver operating characteristic gradually improved as more appointment history was included until around the 20th predictive model. The overbooking method with no-show predictive models suggested incorporating up to the 16th model and outperformed other overbooking methods by as much as 9.4 per cent in the cost per patient while allowing two additional patients in a clinic day. Research limitations/implications - The challenge now is to actually implement the no-show predictive model systematically to further demonstrate its robustness and simplicity in various scheduling systems. Originality/value - This paper provides examples of how to build the no-show predictive models with time-dependent components to improve the overbooking policy. Accurately identifying scheduled patients' show/no-show status allows clinics to proactively schedule patients to reduce the negative impact of patient no-shows.
Illustrative visualization of 3D city models
NASA Astrophysics Data System (ADS)
Doellner, Juergen; Buchholz, Henrik; Nienhaus, Marc; Kirsch, Florian
2005-03-01
This paper presents an illustrative visualization technique that provides expressive representations of large-scale 3D city models, inspired by the tradition of artistic and cartographic visualizations typically found in bird"s-eye view and panoramic maps. We define a collection of city model components and a real-time multi-pass rendering algorithm that achieves comprehensible, abstract 3D city model depictions based on edge enhancement, color-based and shadow-based depth cues, and procedural facade texturing. Illustrative visualization provides an effective visual interface to urban spatial information and associated thematic information complementing visual interfaces based on the Virtual Reality paradigm, offering a huge potential for graphics design. Primary application areas include city and landscape planning, cartoon worlds in computer games, and tourist information systems.
NASA Astrophysics Data System (ADS)
Harvey, R. W. (Bob); Petrov, Yu. V.; Jaeger, E. F.; Berry, L. A.; Bonoli, P. T.; Bader, A.
2015-11-01
A time-dependent simulation of C-Mod pulsed ICRF power is made calculating minority hydrogen ion distribution functions with the CQL3D-Hybrid-FOW finite-orbit-width Fokker-Planck code. ICRF fields are calculated with the AORSA full wave code, and RF diffusion coefficients are obtained from these fields using the DC Lorentz gyro-orbit code. Prior results with a zero-banana-width simulation using the CQL3D/AORSA/DC time-cycles showed a pronounced enhancement of the H distribution in the perpendicular velocity direction compared to results obtained from Stix's quasilinear theory, in general agreement with experiment. The present study compares the new FOW results, including relevant gyro-radius effects, to determine the importance of these effects on the the NPA synthetic diagnostic time-dependence. The new NPA results give increased agreement with experiment, particularly in the ramp-down time after the ICRF pulse. Funded, through subcontract with Massachusetts Institute of Technology, by USDOE sponsored SciDAC Center for Simulation of Wave-Plasma Interactions.
A time dependent anatomically detailed model of cardiac conduction
NASA Technical Reports Server (NTRS)
Saxberg, B. E.; Grumbach, M. P.; Cohen, R. J.
1985-01-01
In order to understand the determinants of transitions in cardiac electrical activity from normal patterns to dysrhythmias such as ventricular fibrillation, we are constructing an anatomically and physiologically detailed finite element simulation of myocardial electrical propagation. A healthy human heart embedded in paraffin was sectioned to provide a detailed anatomical substrate for model calculations. The simulation of propagation includes anisotropy in conduction velocity due to fiber orientation as well as gradients in conduction velocities, absolute and relative refractory periods, action potential duration and electrotonic influence of nearest neighbors. The model also includes changes in the behaviour of myocardial tissue as a function of the past local activity. With this model, we can examine the significance of fiber orientation and time dependence of local propagation parameters on dysrhythmogenesis.
A time dependent anatomically detailed model of cardiac conduction
NASA Technical Reports Server (NTRS)
Saxberg, B. E.; Grumbach, M. P.; Cohen, R. J.
1985-01-01
In order to understand the determinants of transitions in cardiac electrical activity from normal patterns to dysrhythmias such as ventricular fibrillation, we are constructing an anatomically and physiologically detailed finite element simulation of myocardial electrical propagation. A healthy human heart embedded in paraffin was sectioned to provide a detailed anatomical substrate for model calculations. The simulation of propagation includes anisotropy in conduction velocity due to fiber orientation as well as gradients in conduction velocities, absolute and relative refractory periods, action potential duration and electrotonic influence of nearest neighbors. The model also includes changes in the behaviour of myocardial tissue as a function of the past local activity. With this model, we can examine the significance of fiber orientation and time dependence of local propagation parameters on dysrhythmogenesis.
3-D model-based vehicle tracking.
Lou, Jianguang; Tan, Tieniu; Hu, Weiming; Yang, Hao; Maybank, Steven J
2005-10-01
This paper aims at tracking vehicles from monocular intensity image sequences and presents an efficient and robust approach to three-dimensional (3-D) model-based vehicle tracking. Under the weak perspective assumption and the ground-plane constraint, the movements of model projection in the two-dimensional image plane can be decomposed into two motions: translation and rotation. They are the results of the corresponding movements of 3-D translation on the ground plane (GP) and rotation around the normal of the GP, which can be determined separately. A new metric based on point-to-line segment distance is proposed to evaluate the similarity between an image region and an instantiation of a 3-D vehicle model under a given pose. Based on this, we provide an efficient pose refinement method to refine the vehicle's pose parameters. An improved EKF is also proposed to track and to predict vehicle motion with a precise kinematics model. Experimental results with both indoor and outdoor data show that the algorithm obtains desirable performance even under severe occlusion and clutter.
Sensing and compressing 3-D models
Krumm, J.
1998-02-01
The goal of this research project was to create a passive and robust computer vision system for producing 3-D computer models of arbitrary scenes. Although the authors were unsuccessful in achieving the overall goal, several components of this research have shown significant potential. Of particular interest is the application of parametric eigenspace methods for planar pose measurement of partially occluded objects in gray-level images. The techniques presented provide a simple, accurate, and robust solution to the planar pose measurement problem. In addition, the representational efficiency of eigenspace methods used with gray-level features were successfully extended to binary features, which are less sensitive to illumination changes. The results of this research are presented in two papers that were written during the course of this project. The papers are included in sections 2 and 3. The first section of this report summarizes the 3-D modeling efforts.
Lattice percolation approach to 3D modeling of tissue aging
NASA Astrophysics Data System (ADS)
Gorshkov, Vyacheslav; Privman, Vladimir; Libert, Sergiy
2016-11-01
We describe a 3D percolation-type approach to modeling of the processes of aging and certain other properties of tissues analyzed as systems consisting of interacting cells. Lattice sites are designated as regular (healthy) cells, senescent cells, or vacancies left by dead (apoptotic) cells. The system is then studied dynamically with the ongoing processes including regular cell dividing to fill vacant sites, healthy cells becoming senescent or dying, and senescent cells dying. Statistical-mechanics description can provide patterns of time dependence and snapshots of morphological system properties. The developed theoretical modeling approach is found not only to corroborate recent experimental findings that inhibition of senescence can lead to extended lifespan, but also to confirm that, unlike 2D, in 3D senescent cells can contribute to tissue's connectivity/mechanical stability. The latter effect occurs by senescent cells forming the second infinite cluster in the regime when the regular (healthy) cell's infinite cluster still exists.
NASA Astrophysics Data System (ADS)
Mitra, Sunanda
1992-11-01
Different approaches to computational stereo to represent human stereo vision have been developed over the past two decades. The Marr-Poggio theory of human stereo vision is probably the most widely accepted model of the human stereo vision. However, recently developed motion stereo models which use a sequence of images taken by either a moving camera or a moving object provide an alternative method of achieving multi-resolution matching without the use of Laplacian of Gaussian operators. While using image sequences, the baseline between two camera positions for a image pair is changed for the subsequent image pair so as to achieve different resolution for each image pair. Having different baselines also avoids the inherent occlusion problem in stereo vision models. The advantage of using multi-resolution images acquired by camera positioned at different baselines over those acquired by LOG operators is that one does not have to encounter spurious edges often created by zero-crossings in the LOG operated images. Therefore in designing a computer vision system, a motion stereo model is more appropriate than a stereo vision model. However, in some applications where only a stereo pair of images are available, recovery of 3D surfaces of natural scenes are possible in a computationally efficient manner by using cepstrum matching and regularization techniques. Section 2 of this paper describes a motion stereo model using multi-scale cepstrum matching for the detection of disparity between image pairs in a sequence of images and subsequent recovery of 3D surfaces from depth-map obtained by a non convergent triangulation technique. Section 3 presents a 3D surface recovery technique from a stereo pair using cepstrum matching for disparity detection and cubic B-splines for surface smoothing. Section 4 contains the results of 3D surface recovery using both of the techniques mentioned above. Section 5 discusses the merit of 2D cepstrum matching and cubic B
NASA Astrophysics Data System (ADS)
Berchtold, Waldemar; Schäfer, Marcel; Rettig, Michael; Steinebach, Martin
2014-02-01
3D models and applications are of utmost interest in both science and industry. With the increment of their usage, their number and thereby the challenge to correctly identify them increases. Content identification is commonly done by cryptographic hashes. However, they fail as a solution in application scenarios such as computer aided design (CAD), scientific visualization or video games, because even the smallest alteration of the 3D model, e.g. conversion or compression operations, massively changes the cryptographic hash as well. Therefore, this work presents a robust hashing algorithm for 3D mesh data. The algorithm applies several different bit extraction methods. They are built to resist desired alterations of the model as well as malicious attacks intending to prevent correct allocation. The different bit extraction methods are tested against each other and, as far as possible, the hashing algorithm is compared to the state of the art. The parameters tested are robustness, security and runtime performance as well as False Acceptance Rate (FAR) and False Rejection Rate (FRR), also the probability calculation of hash collision is included. The introduced hashing algorithm is kept adaptive e.g. in hash length, to serve as a proper tool for all applications in practice.
Unstructured 3D grid toolbox for modeling and simulation
George, D.
1997-11-01
Computable 3D grids that accurately represent complex multimaterial geometries are essential for both static and time-dependent modeling and simulation. LaGriT, the grid toolbox developed at Los Alamos provides a sophisticated set of initial grid generation, grid maintenance and grid optimization tools. We present example grids that demonstrate the flexibility of the grid generator. Additionally, we present the results of an electrostatic calculation and a grain growth problem that illustrate the grid optimization features and the utility of the grid server architecture.
Fallon FORGE 3D Geologic Model
Doug Blankenship
2016-03-01
An x,y,z scattered data file for the 3D geologic model of the Fallon FORGE site. Model created in Earthvision by Dynamic Graphic Inc. The model was constructed with a grid spacing of 100 m. Geologic surfaces were extrapolated from the input data using a minimum tension gridding algorithm. The data file is tabular data in a text file, with lithology data associated with X,Y,Z grid points. All the relevant information is in the file header (the spatial reference, the projection etc.) In addition all the fields in the data file are identified in the header.
3-D Model Guided Site Recognition
NASA Astrophysics Data System (ADS)
Thevenoux, Patrick; Serfaty, Veronique; Zavidovique, Bertrand; Stamon, Georges
1990-02-01
Herein is the description of the methodology we adopted to develop a set of algorithms performing the automatic recognition and localisation of sites which are observed through an IR camera from a flying mobile. Considered sites are solid buildings such as houses, power-stations... They must be significant enough to allow satisfactory recognition. However they may include planar subparts like roads, greenfields,... To achieve this recognition, 3D site models are recomputed from CAD models to which are added selected attributes. Chosen models are sets of polyhedral facets which may be processed as derived sets of vertices or edges as well. Polyhedral models are particularly fitting general infrared image properties. Geometrical information is worked from the very beginning of the segmentation process. Image processing procedures extract visual features fitting at best the selected model constituents. At first, a 2D image graph is backprojected into a 3D graph thanks to the model (prediction) and then projection onto the 2D space carries the verification from the generated 3D hypotheses, until matching and localisation are completed. Sporadic monocular images are supposed to be output from an infrared camera. Nevertheless radar images, when available, are concurrently supplied. Provided simple data fusion process, radar information improves greatly the detection of emerging sites and the focus of attention on limited areas of the infrared image, from which the effective recognition is performed. A first implementation of the system is currently under completion relying on edge-based models. Extended use of models allowing feature cooperation is planned and other features like points of interest, regions are already taken into account.
Inferential modeling of 3D chromatin structure.
Wang, Siyu; Xu, Jinbo; Zeng, Jianyang
2015-04-30
For eukaryotic cells, the biological processes involving regulatory DNA elements play an important role in cell cycle. Understanding 3D spatial arrangements of chromosomes and revealing long-range chromatin interactions are critical to decipher these biological processes. In recent years, chromosome conformation capture (3C) related techniques have been developed to measure the interaction frequencies between long-range genome loci, which have provided a great opportunity to decode the 3D organization of the genome. In this paper, we develop a new Bayesian framework to derive the 3D architecture of a chromosome from 3C-based data. By modeling each chromosome as a polymer chain, we define the conformational energy based on our current knowledge on polymer physics and use it as prior information in the Bayesian framework. We also propose an expectation-maximization (EM) based algorithm to estimate the unknown parameters of the Bayesian model and infer an ensemble of chromatin structures based on interaction frequency data. We have validated our Bayesian inference approach through cross-validation and verified the computed chromatin conformations using the geometric constraints derived from fluorescence in situ hybridization (FISH) experiments. We have further confirmed the inferred chromatin structures using the known genetic interactions derived from other studies in the literature. Our test results have indicated that our Bayesian framework can compute an accurate ensemble of 3D chromatin conformations that best interpret the distance constraints derived from 3C-based data and also agree with other sources of geometric constraints derived from experimental evidence in the previous studies. The source code of our approach can be found in https://github.com/wangsy11/InfMod3DGen. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
Inferential modeling of 3D chromatin structure
Wang, Siyu; Xu, Jinbo; Zeng, Jianyang
2015-01-01
For eukaryotic cells, the biological processes involving regulatory DNA elements play an important role in cell cycle. Understanding 3D spatial arrangements of chromosomes and revealing long-range chromatin interactions are critical to decipher these biological processes. In recent years, chromosome conformation capture (3C) related techniques have been developed to measure the interaction frequencies between long-range genome loci, which have provided a great opportunity to decode the 3D organization of the genome. In this paper, we develop a new Bayesian framework to derive the 3D architecture of a chromosome from 3C-based data. By modeling each chromosome as a polymer chain, we define the conformational energy based on our current knowledge on polymer physics and use it as prior information in the Bayesian framework. We also propose an expectation-maximization (EM) based algorithm to estimate the unknown parameters of the Bayesian model and infer an ensemble of chromatin structures based on interaction frequency data. We have validated our Bayesian inference approach through cross-validation and verified the computed chromatin conformations using the geometric constraints derived from fluorescence in situ hybridization (FISH) experiments. We have further confirmed the inferred chromatin structures using the known genetic interactions derived from other studies in the literature. Our test results have indicated that our Bayesian framework can compute an accurate ensemble of 3D chromatin conformations that best interpret the distance constraints derived from 3C-based data and also agree with other sources of geometric constraints derived from experimental evidence in the previous studies. The source code of our approach can be found in https://github.com/wangsy11/InfMod3DGen. PMID:25690896
Time-dependent models of grain-forming stellar atmospheres
Woodrow, J.E.J.; Auman, J.R
1982-06-01
Completely time-dependent models of the expanding atmospheres of cool, carbon-rich stars were calculated. The driving force for the expansion was radiation pressure on grains. The grains were assumed to have the structure of graphite with sigma = 1000 ergs cm/sup -2/. The stellar parameters adopted for the models were M = 1.5 M/sub x/O, L = 1.94 x 10/sup 4/ L/sub x/O, C/H = 1.22 x 10/sup -3/, and C/O = 1.76. Two models were generated. Model 1 had T( = 2500 K and model 2, T( = 2400 K. In both models grain nucleation was negligible at supersaturation levels less than 5. At higher supersaturation levels condensation of small (aroughly-equal5.5 x 10/sup -8/ cm) grains was sufficiently great to generate mass flows. The calculated mass loss rate for model 1 was 6.2 x 10/sup -9/ M/sub sun/ yr/sup -1/ and for model 2, 7.4 x 10/sup -8/ M/sub sun/ yr/sup -1/. The mass flow approached a steady state in model 1, but in model 2 a small amplitude pulsation was superposed upon the outward flow. Initially this pulsation was very irregular, but after an elapsed time of 27 x 10/sup 7/ s the model had relaxed into a steady pulsation mode with a period of 6.4 x 10/sup 7/ s. This mode was followed for four periods during which the amplitude of the pulses remained constant. The driving force for this pulsation appears to be an opacity-controlled feedback mechanism which operated between the grain-forming region of the model and the hydrogen dissociation zone. In model 1 the opacity of the grains was too small for this mechanism to produce pulsations.
3D space analysis of dental models
NASA Astrophysics Data System (ADS)
Chuah, Joon H.; Ong, Sim Heng; Kondo, Toshiaki; Foong, Kelvin W. C.; Yong, Than F.
2001-05-01
Space analysis is an important procedure by orthodontists to determine the amount of space available and required for teeth alignment during treatment planning. Traditional manual methods of space analysis are tedious and often inaccurate. Computer-based space analysis methods that work on 2D images have been reported. However, as the space problems in the dental arch exist in all three planes of space, a full 3D analysis of the problems is necessary. This paper describes a visualization and measurement system that analyses 3D images of dental plaster models. Algorithms were developed to determine dental arches. The system is able to record the depths of the Curve of Spee, and quantify space liabilities arising from a non-planar Curve of Spee, malalignment and overjet. Furthermore, the difference between total arch space available and the space required to arrange the teeth in ideal occlusion can be accurately computed. The system for 3D space analysis of the dental arch is an accurate, comprehensive, rapid and repeatable method of space analysis to facilitate proper orthodontic diagnosis and treatment planning.
A time-dependent model for improved biogalvanic tissue characterisation.
Chandler, J H; Culmer, P R; Jayne, D G; Neville, A
2015-10-01
Measurement of the passive electrical resistance of biological tissues through biogalvanic characterisation has been proposed as a simple means of distinguishing healthy from diseased tissue. This method has the potential to provide valuable real-time information when integrated into surgical tools. Characterised tissue resistance values have been shown to be particularly sensitive to external load switching direction and rate, bringing into question the stability and efficacy of the technique. These errors are due to transient variations observed in measurement data that are not accounted for in current electrical models. The presented research proposes the addition of a time-dependent element to the characterisation model to account for losses associated with this transient behaviour. Influence of switching rate has been examined, with the inclusion of transient elements improving the repeatability of the characterised tissue resistance. Application of this model to repeat biogalvanic measurements on a single ex vivo human colon tissue sample with healthy and cancerous (adenocarcinoma) regions showed a statistically significant difference (p < 0.05) between tissue types. In contrast, an insignificant difference (p > 0.05) between tissue types was found when measurements were subjected to the current model, suggesting that the proposed model may allow for improved biogalvanic tissue characterisation. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Ghosh, Sandip; Sharma, Rahul; Adhikari, Satrajit; Varandas, António J. C.
2017-05-01
We report quantum dynamics calculations of the O + OH → H + O2 reaction on the CHIPR (Varandas, 2013) and DMBE IV (Pastrana et al., 1990) potential energy surfaces (PESs) for ground-state HO2 using the 3D time-dependent wavepacket formalism based on hyperspherical coordinates. Reaction probabilities for J = 0 are calculated for several initial rovibrational states of the OH radical (v = 0; j = 0-5). The J-shifting approximation is used to obtain initial state selected rate-coefficients in the range 0-400 K. Total and state-to-state rate-coefficients are predicted in good agreement with recent experimental studies and theoretical calculations.
Time-dependent buoyant puff model for explosive sources
Kansa, E.J.
1997-10-01
This paper presents a new model for explosive puff rise histories that is derived from the strong conservative form of the partial differential equations of mass, momenta, and total energy that are integrated over space to yield a coupled system of time dependent nonlinear ordinary differential equations (ODEs). By allowing the dimensions of the puff to evolve laterally and horizontally, the initial rising spherical shaped puff evolves into a rising ellipsoidal shaped mushroom cloud. This model treats the turbulence that is generated by the puff itself and the ambient atmospheric turbulence as separate mechanisms in determining the puff history. The puff rise history was found to depend not only upon the mass and initial temperature of the explosion, but also upon the local stability conditions of the ambient atmosphere through which the puff rises. This model was calibrated by comparison with the Roller Coaster experiments, ranging from unstable to very stable atmospheric conditions; the agreement of the model history curves with these experimental curves was within 10%.
3D Model of Surfactant Replacement Therapy
NASA Astrophysics Data System (ADS)
Grotberg, James; Tai, Cheng-Feng; Filoche, Marcel
2015-11-01
Surfactant Replacement Therapy (SRT) involves instillation of a liquid-surfactant mixture directly into the lung airway tree. Though successful in neonatal applications, its use in adults had early success followed by failure. We present the first mathematical model of 3D SRT where a liquid plug propagates through the tree from forced inspiration. In two separate modeling steps, the plug first deposits a coating film on the airway wall which subtracts from its volume, a ``coating cost''. Then the plug splits unevenly at the airway bifurcation due to gravity. The steps are repeated until a plug ruptures or reaches the tree endpoint alveoli/acinus. The model generates 3D images of the resulting acinar distribution and calculates two global indexes, efficiency and homogeneity. Simulating published literature, the earlier successful adult SRT studies show comparatively good index values, while the later failed studies do not. Those unsuccessful studies used smaller dose volumes with higher concentration mixtures, apparently assuming a well mixed compartment. The model shows that adult lungs are not well mixed in SRT due to the coating cost and gravity effects. Returning to the higher dose volume protocols could save many thousands of lives annually in the US. Supported by NIH Grants HL85156, HL84370 and Agence Nationale de la Recherche, ANR no. 2010-BLAN-1119-05.
MOSSFRAC: An anisotropic 3D fracture model
Moss, W C; Levatin, J L
2006-08-14
Despite the intense effort for nearly half a century to construct detailed numerical models of plastic flow and plastic damage accumulation, models for describing fracture, an equally important damage mechanism still cannot describe basic fracture phenomena. Typical fracture models set the stress tensor to zero for tensile fracture and set the deviatoric stress tensor to zero for compressive fracture. One consequence is that the simple case of the tensile fracture of a cylinder under combined compressive radial and tensile axial loads is not modeled correctly. The experimental result is a cylinder that can support compressive radial loads, but no axial load, whereas, the typical numerical result is a cylinder with all stresses equal to zero. This incorrect modeling of fracture locally also has a global effect, because material that is fracturing produces stress release waves, which propagate from the fracture and influence the surrounding material. Consequently, it would be useful to have a model that can describe the stress relief and the resulting anisotropy due to fracture. MOSSFRAC is a material model that simulates three-dimensional tensile and shear fracture in initially isotropic elastic-plastic materials, although its framework is also amenable to initially anisotropic materials. It differs from other models by accounting for the effects of cracks on the constitutive response of the material, so that the previously described experiment, as well as complicated fracture scenarios are simulated more accurately. The model is implemented currently in the LLNL hydrocodes DYNA3D, PARADYN, and ALE3D. The purpose of this technical note is to present a complete qualitative description of the model and quantitative descriptions of salient features.
3D Stratigraphic Modeling of Central Aachen
NASA Astrophysics Data System (ADS)
Dong, M.; Neukum, C.; Azzam, R.; Hu, H.
2010-05-01
Since 1980s, advanced computer hardware and software technologies, as well as multidisciplinary research have provided possibilities to develop advanced three dimensional (3D) simulation software for geosciences application. Some countries, such as USA1) and Canada2) 3), have built up regional 3D geological models based on archival geological data. Such models have played huge roles in engineering geology2), hydrogeology2) 3), geothermal industry1) and so on. In cooperating with the Municipality of Aachen, the Department of Engineering Geology of RWTH Aachen University have built up a computer-based 3D stratigraphic model of 50 meter' depth for the center of Aachen, which is a 5 km by 7 km geologically complex area. The uncorrelated data from multi-resources, discontinuous nature and unconformable connection of the units are main challenges for geological modeling in this area. The reliability of 3D geological models largely depends on the quality and quantity of data. Existing 1D and 2D geological data were collected, including 1) approximately 6970 borehole data of different depth compiled in Microsoft Access database and MapInfo database; 2) a Digital Elevation Model (DEM); 3) geological cross sections; and 4) stratigraphic maps in 1m, 2m and 5m depth. Since acquired data are of variable origins, they were managed step by step. The main processes are described below: 1) Typing errors of borehole data were identified and the corrected data were exported to Variowin2.2 to distinguish duplicate points; 2) The surface elevation of borehole data was compared to the DEM, and differences larger than 3m were eliminated. Moreover, where elevation data missed, it was read from the DEM; 3) Considerable data were collected from municipal constructions, such as residential buildings, factories, and roads. Therefore, many boreholes are spatially clustered, and only one or two representative points were picked out in such areas; After above procedures, 5839 boreholes with -x
Self-Consistent and Time-Dependent Solar Wind Models
NASA Technical Reports Server (NTRS)
Ong, K. K.; Musielak, Z. E.; Rosner, R.; Suess, S. T.; Sulkanen, M. E.
1997-01-01
We describe the first results from a self-consistent study of Alfven waves for the time-dependent, single-fluid magnetohydrodynamic (MHD) solar wind equations, using a modified version of the ZEUS MHD code. The wind models we examine are radially symmetrical and magnetized; the initial outflow is described by the standard Parker wind solution. Our study focuses on the effects of Alfven waves on the outflow and is based on solving the full set of the ideal nonlinear MHD equations. In contrast to previous studies, no assumptions regarding wave linearity, wave damping, and wave-flow interaction are made; thus, the models naturally account for the back-reaction of the wind on the waves, as well as for the nonlinear interaction between different types of MHD waves. Our results clearly demonstrate when momentum deposition by Alfven waves in the solar wind can be sufficient to explain the origin of fast streams in solar coronal holes; we discuss the range of wave amplitudes required to obtained such fast stream solutions.
Time Dependent Hadronic Modeling of Flat Spectrum Radio Quasars
NASA Astrophysics Data System (ADS)
Diltz, C.; Böttcher, M.; Fossati, G.
2015-04-01
We introduce a new time-dependent lepto-hadronic model for blazar emission that takes into account the radiation emitted by secondary particles, such as pions and muons, from photo hadronic interactions. Starting from a baseline parameter set guided by a fit to the spectral energy distribution of the blazar 3C 279, we perform a parameter study to investigate the effects of perturbations of the input parameters to mimic different flaring events to study the resulting light curves in the optical, X-ray, high-energy (HE: E\\gt 100 MeV), and very-high-energy (E\\gt 100 GeV) γ-rays as well as the neutrino emission associated with charged-pion and muon decay. We find that flaring events from an increase in the efficiency of Fermi II acceleration will produce a positive correlation between all bandpasses and a marked plateau in the HE γ-ray lightcurve. We also predict a distinctive dip in the HE lightcurve for perturbations caused by a change in the proton injection spectral index. These plateaus/dips could be a tell tale signature of hadronic models for perturbations that lead to more efficient acceleration of high-energy protons in parameter regimes where pion and muon synchrotron emission is non-negligible.
NASA Astrophysics Data System (ADS)
Meirlaen, Koen
2017-04-01
A lot of subjects in geography and geology are linked to the seasons of the earth. Most of the students think that the earth's seasons are caused by the differences in the distance from the sun throughout the year. So as a teacher I tried year after year to explain the motion of the earth around the sun. Even when I used animations/movies/… it still seemed difficult for the students to understand the 3D-situation. Most of the animations only show the start of every season but it's important to demonstrate to the students the motion of the earth during a year so they can see that the tilt of our planet causes the seasons. The earth's axis is tilted by 23.4 degrees to the plane in which it travels around the sun, the ecliptic. So I started to work on a 3D-model on a scale to use in a classroom. It measures approximately 2m by 1m. You can buy all the materials in DIY-shop for less than € 100: wooden plank, lamp, styrofoam spheres (= earth), … I have been using the model for over 4 years now and it's very nice to work with. You can involve the students more and let them investigate for themselves what causes the seasons. The model demonstrates the start of every season, why it is dark for several months in several places on Earth. They can draw the positions of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle on the styrofoam spheres. Also the difference between day and night is well shown on the globes. A lot of subjects in geography and geology are linked to the seasons of the earth: the changes in weather, ocean currents, winds, tropical storms, vegetation, fauna and flora, hours of daylight, … even economy, migration and social health. This way the model can be used in many lessons during the year. The poster session will demonstrate how you can make the 3D-model, some exercises, …
SB3D User Manual, Santa Barbara 3D Radiative Transfer Model
O'Hirok, William
1999-01-01
SB3D is a three-dimensional atmospheric and oceanic radiative transfer model for the Solar spectrum. The microphysics employed in the model are the same as used in the model SBDART. It is assumed that the user of SB3D is familiar with SBDART and IDL. SB3D differs from SBDART in that computations are conducted on media in three-dimensions rather than a single column (i.e. plane-parallel), and a stochastic method (Monte Carlo) is employed instead of a numerical approach (Discrete Ordinates) for estimating a solution to the radiative transfer equation. Because of these two differences between SB3D and SBDART, the input and running of SB3D is more unwieldy and requires compromises between model performance and computational expense. Hence, there is no one correct method for running the model and the user must develop a sense to the proper input and configuration of the model.
Reservoir geology using 3D modelling tools
Dubrule, O.; Samson, P.; Segonds, D.
1996-12-31
The last decade has seen tremendous developments in the area of quantitative geological modelling. These developments have a significant impact on the current practice of constructing reservoir models. A structural model can first be constructed on the basis of depth-converted structural interpretations produced on a seismic interpretation workstation. Surfaces and faults can be represented as geological objects, and interactively modified. Once the tectonic framework has been obtained, intermediate stratigraphic surfaces can be constructed between the main structural surfaces. Within each layer, reservoir attributes can be represented using various techniques. Examples show how the distribution of different facies (i.e. from fine to coarse grain) can be represented, or how various depositional units (for instance channels, crevasses and lobes in a turbidite setting) can be modelled as geological {open_quotes}objects{close_quotes} with complex geometries. Elf Aquitaine, in close co-operation with the GOCAD project in Nancy (France) is investigating how geological models can be made more realistic by developing interactive functionalities. Examples show that, contrary to standard deterministic or geostatistical modelling techniques (which tend to be difficult to control) the use of new 3D tools allows the geologist to interactively modify geological surfaces (including faults) or volumetric properties. Thus, the sensitivity of various economic parameters (oil in place, connected volumes, reserves) to major geological uncertainties can be evaluated. It is argued that future breakthroughs in geological modelling techniques are likely to happen in the development of interactive approaches rather than in the research of new mathematical algorithms.
Reservoir geology using 3D modelling tools
Dubrule, O. ); Samson, P. ); Segonds, D. )
1996-01-01
The last decade has seen tremendous developments in the area of quantitative geological modelling. These developments have a significant impact on the current practice of constructing reservoir models. A structural model can first be constructed on the basis of depth-converted structural interpretations produced on a seismic interpretation workstation. Surfaces and faults can be represented as geological objects, and interactively modified. Once the tectonic framework has been obtained, intermediate stratigraphic surfaces can be constructed between the main structural surfaces. Within each layer, reservoir attributes can be represented using various techniques. Examples show how the distribution of different facies (i.e. from fine to coarse grain) can be represented, or how various depositional units (for instance channels, crevasses and lobes in a turbidite setting) can be modelled as geological [open quotes]objects[close quotes] with complex geometries. Elf Aquitaine, in close co-operation with the GOCAD project in Nancy (France) is investigating how geological models can be made more realistic by developing interactive functionalities. Examples show that, contrary to standard deterministic or geostatistical modelling techniques (which tend to be difficult to control) the use of new 3D tools allows the geologist to interactively modify geological surfaces (including faults) or volumetric properties. Thus, the sensitivity of various economic parameters (oil in place, connected volumes, reserves) to major geological uncertainties can be evaluated. It is argued that future breakthroughs in geological modelling techniques are likely to happen in the development of interactive approaches rather than in the research of new mathematical algorithms.
Scalable 3D GIS environment managed by 3D-XML-based modeling
NASA Astrophysics Data System (ADS)
Shi, Beiqi; Rui, Jianxun; Chen, Neng
2008-10-01
Nowadays, the namely 3D GIS technologies become a key factor in establishing and maintaining large-scale 3D geoinformation services. However, with the rapidly increasing size and complexity of the 3D models being acquired, a pressing needed for suitable data management solutions has become apparent. This paper outlines that storage and exchange of geospatial data between databases and different front ends like 3D models, GIS or internet browsers require a standardized format which is capable to represent instances of 3D GIS models, to minimize loss of information during data transfer and to reduce interface development efforts. After a review of previous methods for spatial 3D data management, a universal lightweight XML-based format for quick and easy sharing of 3D GIS data is presented. 3D data management based on XML is a solution meeting the requirements as stated, which can provide an efficient means for opening a new standard way to create an arbitrary data structure and share it over the Internet. To manage reality-based 3D models, this paper uses 3DXML produced by Dassault Systemes. 3DXML uses opening XML schemas to communicate product geometry, structure and graphical display properties. It can be read, written and enriched by standard tools; and allows users to add extensions based on their own specific requirements. The paper concludes with the presentation of projects from application areas which will benefit from the functionality presented above.
Automated modeling of RNA 3D structure.
Rother, Kristian; Rother, Magdalena; Skiba, Pawel; Bujnicki, Janusz M
2014-01-01
This chapter gives an overview over the current methods for automated modeling of RNA structures, with emphasis on template-based methods. The currently used approaches to RNA modeling are presented with a side view on the protein world, where many similar ideas have been used. Two main programs for automated template-based modeling are presented: ModeRNA assembling structures from fragments and MacroMoleculeBuilder performing a simulation to satisfy spatial restraints. Both approaches have in common that they require an alignment of the target sequence to a known RNA structure that is used as a modeling template. As a way to find promising template structures and to align the target and template sequences, we propose a pipeline combining the ParAlign and Infernal programs on RNA family data from Rfam. We also briefly summarize template-free methods for RNA 3D structure prediction. Typically, RNA structures generated by automated modeling methods require local or global optimization. Thus, we also discuss methods that can be used for local or global refinement of RNA structures.
Regional geothermal 3D modelling in Denmark
NASA Astrophysics Data System (ADS)
Poulsen, S. E.; Balling, N.; Bording, T. S.; Nielsen, S. B.
2012-04-01
In the pursuit of sustainable and low carbon emission energy sources, increased global attention has been given to the exploration and exploitation of geothermal resources within recent decades. In 2009 a national multi-disciplinary geothermal research project was established. As a significant part of this project, 3D temperature modelling is to be carried out, with special emphasis on temperatures of potential geothermal reservoirs in the Danish area. The Danish subsurface encompasses low enthalpy geothermal reservoirs of mainly Triassic and Jurassic age. Geothermal plants at Amager (Copenhagen) and Thisted (Northern Jutland) have the capacity of supplying the district heating network with up to 14 MW and 7 MW, respectively, by withdrawing warm pore water from the Gassum (Lower Jurassic/Upper Triassic) and Bunter (Lower Triassic) sandstone reservoirs, respectively. Explorative studies of the subsurface temperature regime typically are based on a combination of observations and modelling. In this study, the open-source groundwater modelling code MODFLOW is modified to simulate the subsurface temperature distribution in three dimensions by taking advantage of the mathematical similarity between saturated groundwater flow (Darcy flow) and heat conduction. A numerical model of the subsurface geology in Denmark is built and parameterized from lithological information derived from joint interpretation of seismic surveys and borehole information. Boundary conditions are constructed from knowledge about the heat flow from the Earth's interior and the shallow ground temperature. Matrix thermal conductivities have been estimated from analysis of high-resolution temperature logs measured in deep wells and porosity-depth relations are included using interpreted main lithologies. The model takes into account the dependency of temperature and pressure on thermal conductivity. Moreover, a transient model based correction of the paleoclimatic thermal disturbance caused by the
[Digital modeling for the individual mandibular 3D mesh scaffold based on 3D printing technology].
Yan, Rongzeng; Luo, Danmei; Qin, Xiaoyu; Li, Runxin; Rong, Qiguo; Hu, Min
2016-05-01
To investigate an ideal modeling method of designing 3D mesh scaffold substitutes based on tissue engineering to restore mandibular bone defects. By analyzing the theoretical model from titanium scaffolds fabricated by 3D printing, the feasibility and effectiveness of the proposed methodology were verified. Based on the CT scanned data of a subject, the Mimics 15.0 and Geomagic studio 12.0 reverse engineering software were adopted to generate surface model of mandibular bone and the defect area was separated from the 3D model of bone. Then prosthesis was designed via mirror algorithm, in which outer shape was used as the external shape of scaffold. Unigraphics software NX 8.5 was applied on Boolean calculation of subtraction between prosthesis and regular microstructure structure and ANSYS 14.0 software was used to design the inner construction of 3D mesh scaffolds. The topological structure and the geometrical parameters of 3D mesh titanium scaffolds were adjusted according to the aim of optimized structure and maximal strength with minimal weight. The 3D mesh scaffolds solid model through two kinds of computer-aided methods was input into 3D printing equipment to fabricate titanium scaffolds. Individual scaffolds were designed successfully by two modeling methods. The finite element optimization made 10% decrease of the stress peak and volume decrease of 43%, and the porosity increased to 76.32%. This modeling method was validated by 3D printing titanium scaffold to be feasible and effective. 3D printing technology combined with finite element topology optimization to obtain the ideal mandibular 3D mesh scaffold is feasible and effective.
3D Modelling of Kizildag Monument
NASA Astrophysics Data System (ADS)
Karauguz, Güngör; Kalayci, İbrahim; Öğütcü, Sermet
2016-10-01
The most important cultural property that the nations possess is their historical accumulation, and bringing these to light, taking measures to preserve them or at least maintain the continuity of transferring them to next generations by means of recent technic and technology, ought to be the business of present generations. Although, nowadays, intensive documentation and archiving studies are done by means of classical techniques, besides studies towards preserving historical objects, modelling one-to-one or scaled modelling were not possible until recently. Computing devices and the on-going reflection of this, which is acknowledged as digital technology, is widely used in many areas and makes it possible to document and archive historical works. Even virtual forms in quantitative environments can be transferred to next generations in a scaled and one-to-one modelled way. Within this scope, every single artefact categorization belonging to any era or civilization present in our country can be considered in separate study areas. Furthermore, any work or likewise can be evaluated in separate categories. Also, it is possible to construct travelable virtual 3D museums that make it possible to visit these artefacts. Under the auspices of these technologies, it is quite possible to construct single virtual indoor museums or also, at the final stage, a 3D travelable open-air museum, a platform or more precisely, to establish a data system that spreads all over the country on a broad spectrum. With a long-termed, significant and extensive study and a substantial organization, such a data system can be established, which also serves as a serious infrastructure for alternative tourism possibilities. Located beside a stepped altar and right above the Kizildag IV inscription, the offering pot is destructed and rolled away a few meters to the south slope of the mould. Every time visiting these artefacts with our undergraduate students, unfortunately, we observe more
Sahoo, Tapas; Ghosh, Sandip; Adhikari, Satrajit; Sharma, Rahul; Varandas, António J C
2014-07-03
We explore a coupled three-dimensional (3D) time-dependent wave packet formalism in hyperspherical coordinates for a 4D reactive scattering problem on the lowest adiabatic singlet surface (1(1)A') of the D(+) + H2 reaction. The coupling among the wavepackets arises through quantization of the rotation matrix, which represents the orientation of the three particles in space. The required transformation from Jacobi to hyperspherical coordinates and vice versa during initialization and projection of the wave packet on the asymptotic state(s), and the coupled equations of motion, are briefly discussed. With the long-range potential known to contribute significantly on the D(+) + H2 system, we demonstrate the workability of our approach, where the convergence profiles of the reaction probability for the reactive noncharge transfer (RNCT) process [D(+) + H2(v=0, j=0,1) → HD(v',j') + H(+)] are shown for three different collisional energies (1.7, 2.1, and 2.5 eV) with respect to the helicity (K) and total angular momentum (J) quantum numbers. The calculated reactive cross-section is presented as a function of the collision energy for two different initial states of the diatom (v = 0, j = 0, 1).
Ghosh, Sandip; Sahoo, Tapas; Adhikari, Satrajit; Sharma, Rahul; Varandas, António J C
2015-12-17
We implement a coupled three-dimensional (3D) time-dependent wave packet formalism for the 4D reactive scattering problem in hyperspherical coordinates on the accurate double many body expansion (DMBE) potential energy surface (PES) for the ground and first two singlet states (1(1)A', 2(1)A', and 3(1)A') to account for nonadiabatic processes in the D(+) + H2 reaction for both zero and nonzero values of the total angular momentum (J). As the long-range interactions in D(+) + H2 contribute significantly due to nonadiabatic effects, the convergence profiles of reaction probabilities for the reactive noncharge transfer (RNCT), nonreactive charge transfer (NRCT), and reactive charge transfer (RCT) processes are shown for different collisional energies with respect to the helicity (K) and total angular momentum (J) quantum numbers. The total and state-to-state cross sections are presented as a function of the collision energy for the initial rovibrational state v = 0, j = 0 of the diatom, and the calculated cross sections compared with other theoretical and experimental results.
Time dependent flare model with non-LTE radiative transfer
NASA Astrophysics Data System (ADS)
Varady, M.; Karlický, M.; Kašparová, J.; Heinzel, P.
2002-12-01
The first results of a time dependent simulation of chromospheric response to a high energy electron beam are presented. The hybrid code, i.e. a combination of a 1-D hydrodynamic code and a test particle code, has been used to calculate the energy losses of a high energy electron beam propagating through the solar atmosphere and the consequent response of the ambient solar plasma to the energy deposition. The resulting time evolution of the solar plasma temperature, density, velocity and energy deposit on hydrogen has then been used as an input for a time dependent radiative transfer code in the MALI approach to determine the time variation of the Hα line profile. Non-thermal collisional rates have been included in the linearised ESE.
Earthquake Lights: Time-dependent Earth Surface - Ionosphere Coupling Model
NASA Astrophysics Data System (ADS)
Pasko, V. P.
2012-12-01
Co-seismic luminescence, commonly referred to as Earthquake lights (EQLs), is an atmospheric luminous phenomenon occurring during strong earthquakes and lasting from a fraction of a second to a few minutes [e.g., Derr, J. S., Bull. Seismol. Soc. Am., 63, 2177, 1973; St-Laurent, F., et al., Phys. Chem. Earth, 31, 305, 2006; Herauld and Lira, Nat. Hazards Earth Syst. Sci., 11, 1025, 2011]. Laboratory experiments of Freund, F. T., et al. [JGR, 105, 11001, 2000; JASTP, 71, 1824, 2009, and references therein] demonstrate that rocks subjected to stress force can generate electric currents. During earthquakes these currents can deliver significant amounts of net positive charge to the ground-air interface leading to enhancements in the electric field and corona discharges around ground objects [Freund et al., 2009]. The eyewitness reports [Herauld and Lira, 2011] indicate similarities of the blue glow observed during EQLs to St. Elmo's fire observed during thunderstorms around wing tips of airplanes or around the tall masts of sailing ships [e.g., Wescott, E.M., et al., GRL, 23, 3687, 1996]. Recent work indicates that the vertical currents induced in the stressed rock can map to ionospheric altitudes and create 10s of % variations in the total electron content in the Earth's ionosphere above the earthquake active region [Kuo, C. L., et al., JGR, 116, A10317, 2011]. The magnitudes of the vertical currents estimated by Kuo et al. [2011] based on work by Freund et al. [2009] range from 0.01 to 10 μA/m2. In this talk we report results from a new time-dependent model allowing to calculate currents induced in the ambient atmosphere and corona currents under application of vertical stressed rock currents with arbitrary time variation. We will report test results documenting the model performance under conditions: (1) relaxation toward the classic global electric circuit conditions in fair weather regions when ionosphere is maintained at 300 kV with respect to the ground; (2
3-D physical models of amitosis (cytokinesis).
Cheng, Kang; Zou, Changhua
2005-01-01
Based on Newton's laws, extended Coulomb's law and published biological data, we develop our 3-D physical models of natural and normal amitosis (cytokinesis), for prokaryotes (bacterial cells) in M phase. We propose following hypotheses: Chromosome rings exclusion: No normally and naturally replicated chromosome rings (RCR) can occupy the same prokaryote, a bacterial cell. The RCR produce spontaneous and strong electromagnetic fields (EMF), that can be alternated environmentally, in protoplasm and cortex. The EMF is approximately a repulsive quasi-static electric (slowly variant and mostly electric) field (EF). The EF forces between the RCR are strong enough, and orderly accumulate contractile proteins that divide the procaryotes in the cell cortex of division plane or directly split the cell compartment envelope longitudinally. The radial component of the EF forces could also make furrows or cleavages of procaryotes. The EF distribution controls the protoplasm partition and completes the amitosis (cytokinesis). After the cytokinesis, the spontaneous and strong EF disappear because the net charge accumulation becomes weak, in the protoplasm. The exclusion is because the two sets of informative objects (RCR) have identical DNA codes information and they are electro magnetically identical, therefore they repulse from each other. We also compare divisions among eukaryotes, prokaryotes, mitochondria and chloroplasts and propose our hypothesis: The principles of our models are applied to divisions of mitochondria and chloroplasts of eucaryotes too because these division mechanisms are closer than others in a view of physics. Though we develop our model using 1 division plane (i.e., 1 cell is divided into 2 cells) as an example, the principle of our model is applied to the cases with multiple division planes (i.e., 1 cell is divided into multiple cells) too.
3D Models of Stellar Interactions
NASA Astrophysics Data System (ADS)
Mohamed, S.; Podsiadlowski, Ph.; Booth, R.; Maercker, M.; Ramstedt, S.; Vlemmings, W.; Harries, T.; Mackey, J.; Langer, N.; Corradi, R.
2014-04-01
Symbiotic binaries consist of a cool, evolved mass-losing giant and an accreting compact companion. As symbiotic nebulae show similar morphologies to those in planetary nebulae (so much so that it is often difficult to distinguish between the two), they are ideal laboratories for understanding the role a binary companion plays in shaping the circumstellar envelopes in these evolved systems. We will present 3D Smoothed Particle Hydrodynamics (SPH) models of interacting binaries, e.g. R Aquarii and Mira, and discuss the formation of spiral outflows, arcs, shells and equatorial density enhancements.We will also discuss the implications of the former for planetary nebulae, e.g. the Egg Nebula and Cat's Eye, and the latter for the formation of bipolar geometries, e.g. M2-9. We also investigate accretion and angular momentum evolution in symbiotic binaries which may be important to understand the formation of jets and more episodic mass-loss features we see in circumstellar envelopes and the orbital characteristics of binary central stars of planetary nebulae.
Multi-view and 3D deformable part models.
Pepik, Bojan; Stark, Michael; Gehler, Peter; Schiele, Bernt
2015-11-01
As objects are inherently 3D, they have been modeled in 3D in the early days of computer vision. Due to the ambiguities arising from mapping 2D features to 3D models, 3D object representations have been neglected and 2D feature-based models are the predominant paradigm in object detection nowadays. While such models have achieved outstanding bounding box detection performance, they come with limited expressiveness, as they are clearly limited in their capability of reasoning about 3D shape or viewpoints. In this work, we bring the worlds of 3D and 2D object representations closer, by building an object detector which leverages the expressive power of 3D object representations while at the same time can be robustly matched to image evidence. To that end, we gradually extend the successful deformable part model [1] to include viewpoint information and part-level 3D geometry information, resulting in several different models with different level of expressiveness. We end up with a 3D object model, consisting of multiple object parts represented in 3D and a continuous appearance model. We experimentally verify that our models, while providing richer object hypotheses than the 2D object models, provide consistently better joint object localization and viewpoint estimation than the state-of-the-art multi-view and 3D object detectors on various benchmarks (KITTI [2] , 3D object classes [3] , Pascal3D+ [4] , Pascal VOC 2007 [5] , EPFL multi-view cars[6] ).
Time-dependent Models of Magnetospheric Accretion onto Young Stars
NASA Astrophysics Data System (ADS)
Robinson, C. E.; Owen, J. E.; Espaillat, C. C.; Adams, F. C.
2017-04-01
Accretion onto Classical T Tauri stars is thought to take place through the action of magnetospheric processes, with gas in the inner disk being channeled onto the star’s surface by the stellar magnetic field lines. Young stars are known to accrete material in a time-variable manner, and the source of this variability remains an open problem, particularly on the shortest (∼day) timescales. Using one-dimensional time-dependent numerical simulations that follow the field line geometry, we find that for plausibly realistic young stars, steady-state transonic accretion occurs naturally in the absence of any other source of variability. However, we show that if the density in the inner disk varies smoothly in time with ∼day-long timescales (e.g., due to turbulence), this complication can lead to the development of shocks in the accretion column. These shocks propagate along the accretion column and ultimately hit the star, leading to rapid, large amplitude changes in the accretion rate. We argue that when these shocks hit the star, the observed time dependence will be a rapid increase in accretion luminosity, followed by a slower decline, and could be an explanation for some of the short-period variability observed in accreting young stars. Our one-dimensional approach bridges previous analytic work to more complicated multi-dimensional simulations and observations.
3D-GNOME: an integrated web service for structural modeling of the 3D genome.
Szalaj, Przemyslaw; Michalski, Paul J; Wróblewski, Przemysław; Tang, Zhonghui; Kadlof, Michal; Mazzocco, Giovanni; Ruan, Yijun; Plewczynski, Dariusz
2016-07-08
Recent advances in high-throughput chromosome conformation capture (3C) technology, such as Hi-C and ChIA-PET, have demonstrated the importance of 3D genome organization in development, cell differentiation and transcriptional regulation. There is now a widespread need for computational tools to generate and analyze 3D structural models from 3C data. Here we introduce our 3D GeNOme Modeling Engine (3D-GNOME), a web service which generates 3D structures from 3C data and provides tools to visually inspect and annotate the resulting structures, in addition to a variety of statistical plots and heatmaps which characterize the selected genomic region. Users submit a bedpe (paired-end BED format) file containing the locations and strengths of long range contact points, and 3D-GNOME simulates the structure and provides a convenient user interface for further analysis. Alternatively, a user may generate structures using published ChIA-PET data for the GM12878 cell line by simply specifying a genomic region of interest. 3D-GNOME is freely available at http://3dgnome.cent.uw.edu.pl/. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.
3D-GNOME: an integrated web service for structural modeling of the 3D genome
Szalaj, Przemyslaw; Michalski, Paul J.; Wróblewski, Przemysław; Tang, Zhonghui; Kadlof, Michal; Mazzocco, Giovanni; Ruan, Yijun; Plewczynski, Dariusz
2016-01-01
Recent advances in high-throughput chromosome conformation capture (3C) technology, such as Hi-C and ChIA-PET, have demonstrated the importance of 3D genome organization in development, cell differentiation and transcriptional regulation. There is now a widespread need for computational tools to generate and analyze 3D structural models from 3C data. Here we introduce our 3D GeNOme Modeling Engine (3D-GNOME), a web service which generates 3D structures from 3C data and provides tools to visually inspect and annotate the resulting structures, in addition to a variety of statistical plots and heatmaps which characterize the selected genomic region. Users submit a bedpe (paired-end BED format) file containing the locations and strengths of long range contact points, and 3D-GNOME simulates the structure and provides a convenient user interface for further analysis. Alternatively, a user may generate structures using published ChIA-PET data for the GM12878 cell line by simply specifying a genomic region of interest. 3D-GNOME is freely available at http://3dgnome.cent.uw.edu.pl/. PMID:27185892
3D fast wavelet network model-assisted 3D face recognition
NASA Astrophysics Data System (ADS)
Said, Salwa; Jemai, Olfa; Zaied, Mourad; Ben Amar, Chokri
2015-12-01
In last years, the emergence of 3D shape in face recognition is due to its robustness to pose and illumination changes. These attractive benefits are not all the challenges to achieve satisfactory recognition rate. Other challenges such as facial expressions and computing time of matching algorithms remain to be explored. In this context, we propose our 3D face recognition approach using 3D wavelet networks. Our approach contains two stages: learning stage and recognition stage. For the training we propose a novel algorithm based on 3D fast wavelet transform. From 3D coordinates of the face (x,y,z), we proceed to voxelization to get a 3D volume which will be decomposed by 3D fast wavelet transform and modeled after that with a wavelet network, then their associated weights are considered as vector features to represent each training face . For the recognition stage, an unknown identity face is projected on all the training WN to obtain a new vector features after every projection. A similarity score is computed between the old and the obtained vector features. To show the efficiency of our approach, experimental results were performed on all the FRGC v.2 benchmark.
A 3-D shape model of Interamnia
NASA Astrophysics Data System (ADS)
Sato, Isao
2015-08-01
A 3-D shape model of the sixth largest of the main belt asteroids, (704) Interamnia, is presented. The model is reproduced from its two stellar occultation observations and six lightcurves between 1969 and 2011. The first stellar occultation was the occultation of TYC 234500183 on 1996 December 17 observed from 13 sites in the USA. An elliptical cross section of (344.6±9.6km)×(306.2±9.1km), for position angle P=73.4±12.5 was fitted. The lightcurve around the occultation shows that the peak-to-peak amplitude was 0.04 mag. and the occultation phase was just before the minimum. The second stellar occultation was the occultation of HIP 036189 on 2003 March 23 observed from 39 sites in Japan and Hawaii. An elliptical cross section of (349.8±0.9km)×(303.7±1.7km), for position angle P=86.0±1.1 was fitted. A companion of 8.5 mag. of the occulted star was discovered whose separation is 12±2 mas (milli-arcseconds), P=148±11 . A combined analysis of rotational lightcurves and occultation chords can return more information than can be obtained with either technique alone. From follow-up photometric observations of the asteroid between 2003 and 2011, its rotation period is determined to be 8.728967167±0.00000007 hours, which is accurate enough to fix the rotation phases at other occultation events. The derived north pole is λ2000=259±8, β2000=-50±5 (retrograde rotation); the lengths of the three principal axes are 2a=361.8±2.8km, 2b=324.4±5.0km, 2c=297.3±3.5km, and the mean diameter is D=326.8±3.0km. Supposing the mass of Interamnia as (3.5±0.9)×10-11 solar masses, the density is then ρ=3.8±1.0 g cm-3.
Anatomy-based 3D skeleton extraction from femur model.
Gharenazifam, Mina; Arbabi, Ehsan
2014-11-01
Using 3D models of bones can highly improve accuracy and reliability of orthopaedic evaluation. However, it may impose excessive computational load. This article proposes a fully automatic method for extracting a compact model of the femur from its 3D model. The proposed method works by extracting a 3D skeleton based on the clinical parameters of the femur. Therefore, in addition to summarizing a 3D model of the bone, the extracted skeleton would preserve important clinical and anatomical information. The proposed method has been applied on 3D models of 10 femurs and the results have been evaluated for different resolutions of data.
Recovery of time-dependent volatility in option pricing model
NASA Astrophysics Data System (ADS)
Deng, Zui-Cha; Hon, Y. C.; Isakov, V.
2016-11-01
In this paper we investigate an inverse problem of determining the time-dependent volatility from observed market prices of options with different strikes. Due to the non linearity and sparsity of observations, an analytical solution to the problem is generally not available. Numerical approximation is also difficult to obtain using most of the existing numerical algorithms. Based on our recent theoretical results, we apply the linearisation technique to convert the problem into an inverse source problem from which recovery of the unknown volatility function can be achieved. Two kinds of strategies, namely, the integral equation method and the Landweber iterations, are adopted to obtain the stable numerical solution to the inverse problem. Both theoretical analysis and numerical examples confirm that the proposed approaches are effective. The work described in this paper was partially supported by a grant from the Research Grant Council of the Hong Kong Special Administrative Region (Project No. CityU 101112) and grants from the NNSF of China (Nos. 11261029, 11461039), and NSF grants DMS 10-08902 and 15-14886 and by Emylou Keith and Betty Dutcher Distinguished Professorship at the Wichita State University (USA).
A 3D Bubble Merger Model for RTI Mixing
NASA Astrophysics Data System (ADS)
Cheng, Baolian
2015-11-01
In this work we present a model for the merger processes of bubbles at the edge of an unstable acceleration driven mixing layer. Steady acceleration defines a self-similar mixing process, with a time-dependent inverse cascade of structures of increasing size. The time evolution is itself a renormalization group evolution. The model predicts the growth rate of a Rayleigh-Taylor chaotic fluid-mixing layer. The 3-D model differs from the 2-D merger model in several important ways. Beyond the extension of the model to three dimensions, the model contains one phenomenological parameter, the variance of the bubble radii at fixed time. The model also predicts several experimental numbers: the bubble mixing rate, the mean bubble radius, and the bubble height separation at the time of merger. From these we also obtain the bubble height to the radius aspect ratio, which is in good agreement with experiments. Applications to recent NIF and Omega experiments will be discussed. This work was performed under the auspices of the U.S. Department of Energy by the Los Alamos National Laboratory under Contract No. W-7405-ENG-36.
Defect modelling in an interactive 3-D CAD environment
NASA Astrophysics Data System (ADS)
Reilly, D.; Potts, A.; McNab, A.; Toft, M.; Chapman, R. K.
2000-05-01
This paper describes enhancement of the NDT Workbench, as presented at QNDE '98, to include theoretical models for the ultrasonic inspection of smooth planar defects, developed by British Energy and BNFL-Magnox Generation. The Workbench is a PC-based software package for the reconstruction, visualization and analysis of 3-D ultrasonic NDT data in an interactive CAD environment. This extension of the Workbeach now provides the user with a well established modelling approach, coupled with a graphical user interface for: a) configuring the model for flaw size, shape, orientation and location; b) flexible specification of probe parameters; c) selection of scanning surface and scan pattern on the CAD component model; d) presentation of the output as a simulated ultrasound image within the component, or as graphical or tabular displays. The defect modelling facilities of the Workbench can be used for inspection procedure assessment and confirmation of data interpretation, by comparison of overlay images generated from real and simulated data. The modelling technique currently implemented is based on the Geometrical Theory of Diffraction, for simulation of strip-like, circular or elliptical crack responses in the time harmonic or time dependent cases. Eventually, the Workbench will also allow modelling using elastodynamic Kirchhoff theory.
3D Modeling Techniques for Print and Digital Media
NASA Astrophysics Data System (ADS)
Stephens, Megan Ashley
In developing my thesis, I looked to gain skills using ZBrush to create 3D models, 3D scanning, and 3D printing. The models created compared the hearts of several vertebrates and were intended for students attending Comparative Vertebrate Anatomy. I used several resources to create a model of the human heart and was able to work from life while creating heart models from other vertebrates. I successfully learned ZBrush and 3D scanning, and successfully printed 3D heart models. ZBrush allowed me to create several intricate models for use in both animation and print media. The 3D scanning technique did not fit my needs for the project, but may be of use for later projects. I was able to 3D print using two different techniques as well.
3D modeling of metallic grain growth
George, D.; Carlson, N.; Gammel, J.T.; Kuprat, A.
1999-06-01
This paper will describe simulating metallic grain growth using the Gradient Weighted Moving Finite Elements code, GRAIN3D. The authors also describe the set of mesh topology change operations developed to respond to changes in the physical topology such as the collapse of grains and to maintain uniform calculational mesh quality. Validation of the method is demonstrated by comparison to analytic calculations. The authors present results of multigrain simulations where grain boundaries evolve by mean curvature motion and include results which incorporate grain boundary orientation dependence.
The 3D rocket combustor acoustics model
NASA Technical Reports Server (NTRS)
Priem, Richard J.; Breisacher, Kevin J.
1992-01-01
The theory and procedures for determining the characteristics of pressure oscillations in rocket engines with prescribed burning rate oscillations are presented. Analyses including radial and hub baffles and absorbers can be performed in one, two, and three dimensions. Pressure and velocity oscillations calculated using this procedure are presented for the SSME to show the influence of baffles and absorbers on the burning rate oscillations required to achieve neutral stability. Comparisons are made between the results obtained utilizing 1-D, 2-D, and 3-D assumptions with regards to capturing the physical phenomena of interest and computational requirements.
Elastic wave modelling in 3D heterogeneous media: 3D grid method
NASA Astrophysics Data System (ADS)
Jianfeng, Zhang; Tielin, Liu
2002-09-01
We present a new numerical technique for elastic wave modelling in 3D heterogeneous media with surface topography, which is called the 3D grid method in this paper. This work is an extension of the 2D grid method that models P-SV wave propagation in 2D heterogeneous media. Similar to the finite-element method in the discretization of a numerical mesh, the proposed scheme is flexible in incorporating surface topography and curved interfaces; moreover it satisfies the free-surface boundary conditions of 3D topography naturally. The algorithm, developed from a parsimonious staggered-grid scheme, solves the problem using integral equilibrium around each node, instead of satisfying elastodynamic differential equations at each node as in the conventional finite-difference method. The computational cost and memory requirements for the proposed scheme are approximately the same as those used by the same order finite-difference method. In this paper, a mixed tetrahedral and parallelepiped grid method is presented; and the numerical dispersion and stability criteria on the tetrahedral grid method and parallelepiped grid method are discussed in detail. The proposed scheme is successfully tested against an analytical solution for the 3D Lamb problem and a solution of the boundary method for the diffraction of a hemispherical crater. Moreover, examples of surface-wave propagation in an elastic half-space with a semi-cylindrical trench on the surface and 3D plane-layered model are presented.
3D modeling based on CityEngine
NASA Astrophysics Data System (ADS)
Jia, Guangyin; Liao, Kaiju
2017-03-01
Currently, there are many 3D modeling softwares, like 3DMAX, AUTOCAD, and more populous BIM softwares represented by REVIT. CityEngine modeling software introduced in this paper can fully utilize the existing GIS data and combine other built models to make 3D modeling on internal and external part of buildings in a rapid and batch manner, so as to improve the 3D modeling efficiency.
NASA Astrophysics Data System (ADS)
Gerndt, Andreas M.; Engelke, Wito; Giuranna, Marco; Vandaele, Ann C.; Neary, Lori; Aoki, Shohei; Kasaba, Yasumasa; Garcia, Arturo; Fernando, Terrence; Roberts, David; CROSS DRIVE Team
2016-10-01
Atmospheric phenomena of Mars can be highly dynamic and have daily and seasonal variations. Planetary-scale wavelike disturbances, for example, are frequently observed in Mars' polar winter atmosphere. Possible sources of the wave activity were suggested to be dynamical instabilities and quasi-stationary planetary waves, i.e. waves that arise predominantly via zonally asymmetric surface properties. For a comprehensive understanding of these phenomena, single layers of altitude have to be analyzed carefully and relations between different atmospheric quantities and interaction with the surface of Mars have to be considered. The CROSS DRIVE project tries to address the presentation of those data with a global view by means of virtual reality techniques. Complex orbiter data from spectrometer and observation data from Earth are combined with global circulation models and high-resolution terrain data and images available from Mars Express or MRO instruments. Scientists can interactively extract features from those dataset and can change visualization parameters in real-time in order to emphasize findings. Stereoscopic views allow for perception of the actual 3D behavior of Mars's atmosphere. A very important feature of the visualization system is the possibility to connect distributed workspaces together. This enables discussions between distributed working groups. The workspace can scale from virtual reality systems to expert desktop applications to web-based project portals. If multiple virtual environments are connected, the 3D position of each individual user is captured and used to depict the scientist as an avatar in the virtual world. The appearance of the avatar can also scale from simple annotations to complex avatars using tele-presence technology to reconstruct the users in 3D. Any change of the feature set (annotations, cutplanes, volume rendering, etc.) within the VR is immediately exchanged between all connected users. This allows that everybody is always
Single-Tooth Modeling for 3D Dental Model
Yuan, Tianran; Liao, Wenhe; Dai, Ning; Cheng, Xiaosheng; Yu, Qing
2010-01-01
An integrated single-tooth modeling scheme is proposed for the 3D dental model acquired by optical digitizers. The cores of the modeling scheme are fusion regions extraction, single tooth shape restoration, and single tooth separation. According to the “valley” shape-like characters of the fusion regions between two adjoining teeth, the regions of the 3D dental model are analyzed and classified based on the minimum curvatures of the surface. The single tooth shape is restored according to the bioinformation along the hole boundary, which is generated after the fusion region being removed. By using the extracted boundary from the blending regions between the teeth and soft tissues as reference, the teeth can be separated from the 3D dental model one by one correctly. Experimental results show that the proposed method can achieve satisfying modeling results with high-degree approximation of the real tooth and meet the requirements of clinical oral medicine. PMID:20689718
The 3D Reference Earth Model (REM-3D): Update and Outlook
NASA Astrophysics Data System (ADS)
Lekic, V.; Moulik, P.; Romanowicz, B. A.; Dziewonski, A. M.
2016-12-01
Elastic properties of the Earth's interior (e.g. density, rigidity, compressibility, anisotropy) vary spatially due to changes in temperature, pressure, composition, and flow. In the 20th century, seismologists have constructed reference models of how these quantities vary with depth, notably the PREM model of Dziewonski and Anderson (1981). These 1D reference earth models have proven indispensable in earthquake location, imaging of interior structure, understanding material properties under extreme conditions, and as a reference in other fields, such as particle physics and astronomy. Over the past three decades, more sophisticated efforts by seismologists have yielded several generations of models of how properties vary not only with depth, but also laterally. Yet, though these three-dimensional (3D) models exhibit compelling similarities at large scales, differences in the methodology, representation of structure, and dataset upon which they are based, have prevented the creation of 3D community reference models. We propose to overcome these challenges by compiling, reconciling, and distributing a long period (>15 s) reference seismic dataset, from which we will construct a 3D seismic reference model (REM-3D) for the Earth's mantle, which will come in two flavors: a long wavelength smoothly parameterized model and a set of regional profiles. Here, we summarize progress made in the construction of the reference long period dataset, and present preliminary versions of the REM-3D in order to illustrate the two flavors of REM-3D and their relative advantages and disadvantages. As a community reference model and with fully quantified uncertainties and tradeoffs, REM-3D will facilitate Earth imaging studies, earthquake characterization, inferences on temperature and composition in the deep interior, and be of improved utility to emerging scientific endeavors, such as neutrino geoscience. In this presentation, we outline the outlook for setting up advisory community
Dark Energy Models with a Time-Dependent Gravitational Constant
NASA Astrophysics Data System (ADS)
Ray, Saibal; Mukhopadhyay, Utpal; Choudhury, S. B. Dutta
Two phenomenological models of Λ, viz. Λ ˜ (˙ a/a)2 and Λ ˜ ḋ a/a, are studied under the assumption that G is a time-variable parameter. Both models show that G is inversely proportional to time, as suggested earlier by others, including Dirac. The models considered here can be matched with observational results by properly tuning the parameters of the models. Our analysis shows that the Λ ˜ ḋ a/a model corresponds to a repulsive situation and hence correlates with the present status of the accelerating Universe. The other model, Λ ˜ (˙ a/a)2, is in general attractive in nature. Moreover, it is seen that due to the combined effect of time-variable Λ and G the Universe evolved with acceleration as well as deceleration. Deceleration indicates a "big crunch".
Dynamical coarse grained models with realistic time dependence
NASA Astrophysics Data System (ADS)
Andersen, Hans
2015-03-01
Coarse grained (CG) models of molecular systems, with fewer mechanical degrees of freedom than an all-atom model, are used extensively in chemical physics. It is generally accepted that a coarse grained model that accurately describes equilibrium structural properties (as a result of having a well constructed CG potential energy function) does not necessarily exhibit appropriate dynamical behavior when simulated using conservative Hamiltonian dynamics for the CG degrees of freedom on the CG potential energy surface. Attempts to develop accurate CG dynamic models usually focus on replacing Hamiltonian motion by stochastic but Markovian dynamics on that surface, such as Langevin or Brownian dynamics. However, depending on the nature of the system and the extent of the coarse graining, a Markovian dynamics for the CG degrees of freedom may not be appropriate. We consider the problem of constructing dynamic CG models within the context of the Multi-Scale Coarse Graining (MS-CG) method of Voth and coworkers. We propose a method of converting an MS-CG model into a dynamic CG model by adding degrees of freedom to it in the form of a small number of fictitious particles that interact with the CG degrees of freedom in simple ways and that are subject to Langevin forces. The dynamic models are members of a class of nonlinear systems interacting with special heat baths that was studied by Zwanzig [R. Zwanzig, J. Stat. Phys. 9, 215 (1973)]. The dynamic models generate a non-Markovian dynamics for the CG degrees of freedom, but they can be easily simulated using standard molecular dynamics simulation programs. We present tests of this method on a series of simple examples that demonstrate that the method provides realistic dynamical CG models that have non-Markovian or close to Markovian behavior that is consistent with the actual dynamical behavior of the all-atom system used to construct the CG model. The dynamic CG models have computational requirements that are similar to
3D tumor models: history, advances and future perspectives.
Benien, Parul; Swami, Archana
2014-05-01
Evaluation of cancer therapeutics by utilizing 3D tumor models, before clinical studies, could be more advantageous than conventional 2D tumor models (monolayer cultures). The 3D systems mimic the tumor microenvironment more closely than 2D systems. The following review discusses the various 3D tumor models present today with the advantages and limitations of each. 3D tumor models replicate the elements of a tumor microenvironment such as hypoxia, necrosis, angiogenesis and cell adhesion. The review introduces application of techniques such as microfluidics, imaging and tissue engineering to improve the 3D tumor models. Despite their tremendous potential to better screen chemotherapeutics, 3D tumor models still have a long way to go before they are used commonly as in vitro tumor models in pharmaceutical industrial research.
Investigation of surface wave amplitudes in 3-D velocity and 3-D Q models
NASA Astrophysics Data System (ADS)
Ruan, Y.; Zhou, Y.
2010-12-01
It has been long recognized that seismic amplitudes depend on both wave speed structures and anelasticity (Q) structures. However, the effects of lateral heterogeneities in wave speed and Q structures on seismic amplitudes has not been well understood. We investigate the effects of 3-D wave speed and 3-D anelasticity (Q) structures on surface-wave amplitudes based upon wave propagation simulations of twelve globally-distributed earthquakes and 801 stations in Earth models with and without lateral heterogeneities in wave speed and anelasticity using a Spectral Element Method (SEM). Our tomographic-like 3-D Q models are converted from a velocity model S20RTS using a set of reasonable mineralogical parameters, assuming lateral perturbations in both velocity and Q are due to temperature perturbations. Surface-wave amplitude variations of SEM seismograms are measured in the period range of 50--200 s using boxcar taper, cosine taper and Slepian multi-tapers. We calculate ray-theoretical predictions of surface-wave amplitude perturbations due to elastic focusing, attenuation, and anelastic focusing which respectively depend upon the second spatial derivative (''roughness'') of perturbations in phase velocity, 1/Q, and the roughness of perturbations in 1/Q. Both numerical experiments and theoretical calculations show that (1) for short-period (~ 50 s) surface waves, the effects of amplitude attenuation due to 3-D Q structures are comparable with elastic focusing effects due to 3-D wave speed structures; and (2) for long-period (> 100 s) surface waves, the effects of attenuation become much weaker than elastic focusing; and (3) elastic focusing effects are correlated with anelastic focusing at all periods due to the correlation between velocity and Q models; and (4) amplitude perturbations are depend on measurement techniques and therefore cannot be directly compared with ray-theoretical predictions because ray theory does not account for the effects of measurement
3D transient model for CO II laser hardening
NASA Astrophysics Data System (ADS)
Tani, G.; Orazi, L.; Fortunato, A.; Campana, G.; Ascari, A.
2008-01-01
A 3D numerical model for the surface hardening process simulation carried out by means of a CO2 laser source is presented. The model is able to predict the extension of the treated area into the workpiece, the type of the resulting micro-structure and the optimal laser path strategy in order to minimize the micro-structural softening due to the tempering effect. The Fourier equation is solved using the Finite Difference Method (FDM) applied on a generical grid obtained by means of the domain discretization. The resulting time dependent temperature distribution into the workpiece is used for the evaluation of the induced heating cycle. By calculating the cooling velocity, the micro-structure transformation is determined together with the hardness in every point of the domain. The hardness reduction due to the tempering effect is also predictible. The computational times are small and the software is very suitable in industrial environment in the early stage of the process planning when several simulation runs must be performed. The modeling activity was developed by considering the class of the hypo-eutectoid steel. The experimental tests were realized on a C43 steel plate. The good agreement between the theoretical and experimental results is shown.
From medical imaging data to 3D printed anatomical models.
Bücking, Thore M; Hill, Emma R; Robertson, James L; Maneas, Efthymios; Plumb, Andrew A; Nikitichev, Daniil I
2017-01-01
Anatomical models are important training and teaching tools in the clinical environment and are routinely used in medical imaging research. Advances in segmentation algorithms and increased availability of three-dimensional (3D) printers have made it possible to create cost-efficient patient-specific models without expert knowledge. We introduce a general workflow that can be used to convert volumetric medical imaging data (as generated by Computer Tomography (CT)) to 3D printed physical models. This process is broken up into three steps: image segmentation, mesh refinement and 3D printing. To lower the barrier to entry and provide the best options when aiming to 3D print an anatomical model from medical images, we provide an overview of relevant free and open-source image segmentation tools as well as 3D printing technologies. We demonstrate the utility of this streamlined workflow by creating models of ribs, liver, and lung using a Fused Deposition Modelling 3D printer.
From medical imaging data to 3D printed anatomical models
Hill, Emma R.; Robertson, James L.; Maneas, Efthymios; Plumb, Andrew A.; Nikitichev, Daniil I.
2017-01-01
Anatomical models are important training and teaching tools in the clinical environment and are routinely used in medical imaging research. Advances in segmentation algorithms and increased availability of three-dimensional (3D) printers have made it possible to create cost-efficient patient-specific models without expert knowledge. We introduce a general workflow that can be used to convert volumetric medical imaging data (as generated by Computer Tomography (CT)) to 3D printed physical models. This process is broken up into three steps: image segmentation, mesh refinement and 3D printing. To lower the barrier to entry and provide the best options when aiming to 3D print an anatomical model from medical images, we provide an overview of relevant free and open-source image segmentation tools as well as 3D printing technologies. We demonstrate the utility of this streamlined workflow by creating models of ribs, liver, and lung using a Fused Deposition Modelling 3D printer. PMID:28562693
Life in 3D is never flat: 3D models to optimise drug delivery.
Fitzgerald, Kathleen A; Malhotra, Meenakshi; Curtin, Caroline M; O' Brien, Fergal J; O' Driscoll, Caitriona M
2015-10-10
The development of safe, effective and patient-acceptable drug products is an expensive and lengthy process and the risk of failure at different stages of the development life-cycle is high. Improved biopharmaceutical tools which are robust, easy to use and accurately predict the in vivo response are urgently required to help address these issues. In this review the advantages and challenges of in vitro 3D versus 2D cell culture models will be discussed in terms of evaluating new drug products at the pre-clinical development stage. Examples of models with a 3D architecture including scaffolds, cell-derived matrices, multicellular spheroids and biochips will be described. The ability to simulate the microenvironment of tumours and vital organs including the liver, kidney, heart and intestine which have major impact on drug absorption, distribution, metabolism and toxicity will be evaluated. Examples of the application of 3D models including a role in formulation development, pharmacokinetic profiling and toxicity testing will be critically assessed. Although utilisation of 3D cell culture models in the field of drug delivery is still in its infancy, the area is attracting high levels of interest and is likely to become a significant in vitro tool to assist in drug product development thus reducing the requirement for unnecessary animal studies. Copyright © 2015 Elsevier B.V. All rights reserved.
A voter model with time dependent flip rates
NASA Astrophysics Data System (ADS)
Baxter, G. J.
2011-09-01
We introduce time variation in the flip rates of the voter model. This type of generalization may be applied to other diffusion-like models in which interaction rates at the microscopic level may change with time, for example in models of language change, allowing the representation of changes in speakers' learning rates over their lifetime. The mean time taken to reach consensus varies in a nontrivial way with the rate of change of the flip rates, varying between bounds given by the mean consensus times for static homogeneous (the original voter model) and static heterogeneous flip rates. By considering the mean time between interactions for each agent, we derive excellent estimates of the mean consensus times and exit probabilities for any timescale of flip rate variation. The scaling of consensus times with population size on complex networks is correctly predicted, and is as would be expected for the ordinary voter model. Heterogeneity in the initial distribution of opinions has a strong effect, considerably reducing the mean time to consensus, while increasing the probability of survival of the opinion which initially occupies the most slowly changing agents. The mean times taken to reach consensus for different states are very different. An opinion originally held by the fastest changing agents has a smaller chance of succeeding, and takes much longer to do so than an evenly distributed opinion.
A time dependent model for the activation of COMPTEL
Varendorff, Martin; Oberlack, Uwe; Weidenspointner, Georg; Diehl, Roland; Dijk, Rob van; McConnell, Mark; Ryan, James
1997-05-10
The structure of the CGRO satellite is irradiated by cosmic rays and trapped particles from radiation belts. These incident particles produce radioactive nuclei in nuclear reactions with the satellite structure. Most of the radiation dose can be attributed to the passages through the South Atlantic Anomaly. The incident particle flux on the COMPTEL instrument is estimated from the event rate of a plastic scintillation detector. This event rate is modeled with a Neural Network simulation. The increase of the event rate during SAA passages is taken as a measure for the amount of induced radioactivity. A Neural Network Model is used to derive the buildup of radioactive nuclei in the instrument over the first five years of the mission. Measurements of the internal {sup 22}Na- and {sup 24}Na-activity are used to estimate the proton flux in the SAA. The result is consistent with earlier measurements and models.
3D Face Modeling Using the Multi-Deformable Method
Hwang, Jinkyu; Yu, Sunjin; Kim, Joongrock; Lee, Sangyoun
2012-01-01
In this paper, we focus on the problem of the accuracy performance of 3D face modeling techniques using corresponding features in multiple views, which is quite sensitive to feature extraction errors. To solve the problem, we adopt a statistical model-based 3D face modeling approach in a mirror system consisting of two mirrors and a camera. The overall procedure of our 3D facial modeling method has two primary steps: 3D facial shape estimation using a multiple 3D face deformable model and texture mapping using seamless cloning that is a type of gradient-domain blending. To evaluate our method's performance, we generate 3D faces of 30 individuals and then carry out two tests: accuracy test and robustness test. Our method shows not only highly accurate 3D face shape results when compared with the ground truth, but also robustness to feature extraction errors. Moreover, 3D face rendering results intuitively show that our method is more robust to feature extraction errors than other 3D face modeling methods. An additional contribution of our method is that a wide range of face textures can be acquired by the mirror system. By using this texture map, we generate realistic 3D face for individuals at the end of the paper. PMID:23201976
3D Face modeling using the multi-deformable method.
Hwang, Jinkyu; Yu, Sunjin; Kim, Joongrock; Lee, Sangyoun
2012-09-25
In this paper, we focus on the problem of the accuracy performance of 3D face modeling techniques using corresponding features in multiple views, which is quite sensitive to feature extraction errors. To solve the problem, we adopt a statistical model-based 3D face modeling approach in a mirror system consisting of two mirrors and a camera. The overall procedure of our 3D facial modeling method has two primary steps: 3D facial shape estimation using a multiple 3D face deformable model and texture mapping using seamless cloning that is a type of gradient-domain blending. To evaluate our method's performance, we generate 3D faces of 30 individuals and then carry out two tests: accuracy test and robustness test. Our method shows not only highly accurate 3D face shape results when compared with the ground truth, but also robustness to feature extraction errors. Moreover, 3D face rendering results intuitively show that our method is more robust to feature extraction errors than other 3D face modeling methods. An additional contribution of our method is that a wide range of face textures can be acquired by the mirror system. By using this texture map, we generate realistic 3D face for individuals at the end of the paper.
TIME-DEPENDENT STOCHASTIC ACCELERATION MODEL FOR FERMI BUBBLES
Sasaki, Kento; Asano, Katsuaki; Terasawa, Toshio E-mail: asanok@icrr.u-tokyo.ac.jp
2015-12-01
We study stochastic acceleration models for the Fermi bubbles. Turbulence is excited just behind the shock front via Kelvin–Helmholtz, Rayleigh–Taylor, or Richtmyer–Meshkov instabilities, and plasma particles are continuously accelerated by the interaction with the turbulence. The turbulence gradually decays as it goes away from the shock fronts. Adopting a phenomenological model for the stochastic acceleration, we explicitly solve the temporal evolution of the particle energy distribution in the turbulence. Our results show that the spatial distribution of high-energy particles is different from those for a steady solution. We also show that the contribution of electrons that escaped from the acceleration regions significantly softens the photon spectrum. The photon spectrum and surface brightness profile are reproduced by our models. If the escape efficiency is very high, the radio flux from the escaped low-energy electrons can be comparable to that of the WMAP haze. We also demonstrate hadronic models with the stochastic acceleration, but they are unlikely in the viewpoint of the energy budget.
Modeling and Correcting the Time-Dependent ACS PSF
NASA Technical Reports Server (NTRS)
Rhodes, Jason; Massey, Richard; Albert, Justin; Taylor, James E.; Koekemoer, Anton M.; Leauthaud, Alexie
2006-01-01
The ability to accurately measure the shapes of faint objects in images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) depends upon detailed knowledge of the Point Spread Function (PSF). We show that thermal fluctuations cause the PSF of the ACS Wide Field Camera (WFC) to vary over time. We describe a modified version of the TinyTim PSF modeling software to create artificial grids of stars across the ACS field of view at a range of telescope focus values. These models closely resemble the stars in real ACS images. Using 10 bright stars in a real image, we have been able to measure HST s apparent focus at the time of the exposure. TinyTim can then be used to model the PSF at any position on the ACS field of view. This obviates the need for images of dense stellar fields at different focus values, or interpolation between the few observed stars. We show that residual differences between our TinyTim models and real data are likely due to the effects of Charge Transfer Efficiency (CTE) degradation. Furthermore, we discuss stochastic noise that is added to the shape of point sources when distortion is removed, and we present MultiDrizzle parameters that are optimal for weak lensing science. Specifically, we find that reducing the MultiDrizzle output pixel scale and choosing a Gaussian kernel significantly stabilizes the resulting PSF after image combination, while still eliminating cosmic rays/bad pixels, and correcting the large geometric distortion in the ACS. We discuss future plans, which include more detailed study of the effects of CTE degradation on object shapes and releasing our TinyTim models to the astronomical community.
TIME-DEPENDENT MODELING OF PULSAR WIND NEBULAE
Vorster, M. J.; Ferreira, S. E. S.; Tibolla, O.; Kaufmann, S. E-mail: omar.tibolla@gmail.com
2013-08-20
A spatially independent model that calculates the time evolution of the electron spectrum in a spherically expanding pulsar wind nebula (PWN) is presented, allowing one to make broadband predictions for the PWN's non-thermal radiation. The source spectrum of electrons injected at the termination shock of the PWN is chosen to be a broken power law. In contrast to previous PWN models of a similar nature, the source spectrum has a discontinuity in intensity at the transition between the low- and high-energy components. To test the model, it is applied to the young PWN G21.5-0.9, where it is found that a discontinuous source spectrum can model the emission at all wavelengths better than a continuous one. The model is also applied to the unidentified sources HESS J1427-608 and HESS J1507-622. Parameters are derived for these two candidate nebulae that are consistent with the values predicted for other PWNe. For HESS J1427-608, a present day magnetic field of B{sub age} = 0.4 {mu}G is derived. As a result of the small present day magnetic field, this source has a low synchrotron luminosity, while remaining bright at GeV/TeV energies. It is therefore possible to interpret HESS J1427-608 within the ancient PWN scenario. For the second candidate PWN HESS J1507-622, a present day magnetic field of B{sub age} = 1.7 {mu}G is derived. Furthermore, for this candidate PWN a scenario is favored in the present paper in which HESS J1507-622 has been compressed by the reverse shock of the supernova remnant.
NASA Astrophysics Data System (ADS)
Ciardi, A.; Chittenden, J. P.; Lebedev, S. V.; Bland, S. N.; Jennings, C. A.
2003-10-01
X-pinch produced plasmas are an intense source of soft x-rays generated by passing a large, fast rising current through two or more thin metallic wires crossed in the shape of <93>an "X". During the current pulse, the plasma is pinched at the crossing point where a dense Z-pinch plasma column develops. Further compression produces micron sized x-ray hot spots with energy densities in excess of ˜10^24 eV cm-3. We present 3D resistive magnetohydrodynamic simulations of two- and four-wire X-pinches for a variety of wire materials. The simulations naturally follow the evolution of the X-pinch: jet-like structures on axis, formation of a Z-pinch and its subsequent rapid evolution and production of x-ray hot spots. The effects of wire material and wire number are studied with particular consideration to the relationship between the magnetic confinement and radiative cooling mechanisms, which ultimately determine the complex behaviour of the X-pinch.
Time dependent mechanical modeling for polymers based on network theory
Billon, Noëlle
2016-05-18
Despite of a lot of attempts during recent years, complex mechanical behaviour of polymers remains incompletely modelled, making industrial design of structures under complex, cyclic and hard loadings not totally reliable. The non linear and dissipative viscoelastic, viscoplastic behaviour of those materials impose to take into account non linear and combined effects of mechanical and thermal phenomena. In this view, a visco-hyperelastic, viscoplastic model, based on network description of the material has recently been developed and designed in a complete thermodynamic frame in order to take into account those main thermo-mechanical couplings. Also, a way to account for coupled effects of strain-rate and temperature was suggested. First experimental validations conducted in the 1D limit on amorphous rubbery like PMMA in isothermal conditions led to pretty goods results. In this paper a more complete formalism is presented and validated in the case of a semi crystalline polymer, a PA66 and a PET (either amorphous or semi crystalline) are used. Protocol for identification of constitutive parameters is described. It is concluded that this new approach should be the route to accurately model thermo-mechanical behaviour of polymers using a reduced number of parameters of some physical meaning.
Time-dependent recycling modeling with edge plasma transport codes
NASA Astrophysics Data System (ADS)
Pigarov, A.; Krasheninnikov, S.; Rognlien, T.; Taverniers, S.; Hollmann, E.
2013-10-01
First,we discuss extensions to Macroblob approach which allow to simulate more accurately dynamics of ELMs, pedestal and edge transport with UEDGE code. Second,we present UEDGE modeling results for H mode discharge with infrequent ELMs and large pedestal losses on DIII-D. In modeled sequence of ELMs this discharge attains a dynamic equilibrium. Temporal evolution of pedestal plasma profiles, spectral line emission, and surface temperature matching experimental data over ELM cycle is discussed. Analysis of dynamic gas balance highlights important role of material surfaces. We quantified the wall outgassing between ELMs as 3X the NBI fueling and the recycling coefficient as 0.8 for wall pumping via macroblob-wall interactions. Third,we also present results from multiphysics version of UEDGE with built-in, reduced, 1-D wall models and analyze the role of various PMI processes. Progress in framework-coupled UEDGE/WALLPSI code is discussed. Finally, implicit coupling schemes are important feature of multiphysics codes and we report on the results of parametric analysis of convergence and performance for Picard and Newton iterations in a system of coupled deterministic-stochastic ODE and proposed modifications enhancing convergence.
Time-Dependent Traveling Wave Tube Model for Intersymbol Interference Investigations
NASA Technical Reports Server (NTRS)
Kory, Carol L.; Andro, Monty; Downey, Alan (Technical Monitor)
2001-01-01
For the first time, a computational model has been used to provide a direct description of the effects of the traveling wave tube (TWT) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion, gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept-amplitude and/or swept-frequency data. The fully three-dimensional (3D), time-dependent, TWT interaction model using the electromagnetic code MAFIA is presented. This model is used to investigate assumptions made in TWT black-box models used in communication system level simulations. In addition, digital signal performance, including intersymbol interference (ISI), is compared using direct data input into the MAFIA model and using the system level analysis tool, SPW.
Comparing a quasi-3D to a full 3D nearshore circulation model: SHORECIRC and ROMS
Haas, K.A.; Warner, J.C.
2009-01-01
Predictions of nearshore and surf zone processes are important for determining coastal circulation, impacts of storms, navigation, and recreational safety. Numerical modeling of these systems facilitates advancements in our understanding of coastal changes and can provide predictive capabilities for resource managers. There exists many nearshore coastal circulation models, however they are mostly limited or typically only applied as depth integrated models. SHORECIRC is an established surf zone circulation model that is quasi-3D to allow the effect of the variability in the vertical structure of the currents while maintaining the computational advantage of a 2DH model. Here we compare SHORECIRC to ROMS, a fully 3D ocean circulation model which now includes a three dimensional formulation for the wave-driven flows. We compare the models with three different test applications for: (i) spectral waves approaching a plane beach with an oblique angle of incidence; (ii) monochromatic waves driving longshore currents in a laboratory basin; and (iii) monochromatic waves on a barred beach with rip channels in a laboratory basin. Results identify that the models are very similar for the depth integrated flows and qualitatively consistent for the vertically varying components. The differences are primarily the result of the vertically varying radiation stress utilized by ROMS and the utilization of long wave theory for the radiation stress formulation in vertical varying momentum balance by SHORECIRC. The quasi-3D model is faster, however the applicability of the fully 3D model allows it to extend over a broader range of processes, temporal, and spatial scales. ?? 2008 Elsevier Ltd.
Comparing a quasi-3D to a full 3D nearshore circulation model: SHORECIRC and ROMS
Warner, John C.; Haas, Kevin A.
2009-01-01
Predictions of nearshore and surf zone processes are important for determining coastal circulation, impacts of storms, navigation, and recreational safety. Numerical modeling of these systems facilitates advancements in our understanding of coastal changes and can provide predictive capabilities for resource managers. There exists many nearshore coastal circulation models, however they are mostly limited or typically only applied as depth integrated models. SHORECIRC is an established surf zone circulation model that is quasi-3D to allow the effect of the variability in the vertical structure of the currents while maintaining the computational advantage of a 2DH model. Here we compare SHORECIRC to ROMS, a fully 3D ocean circulation model which now includes a three dimensional formulation for the wave-driven flows. We compare the models with three different test applications for: (i) spectral waves approaching a plane beach with an oblique angle of incidence; (ii) monochromatic waves driving longshore currents in a laboratory basin; and (iii) monochromatic waves on a barred beach with rip channels in a laboratory basin. Results identify that the models are very similar for the depth integrated flows and qualitatively consistent for the vertically varying components. The differences are primarily the result of the vertically varying radiation stress utilized by ROMS and the utilization of long wave theory for the radiation stress formulation in vertical varying momentum balance by SHORECIRC. The quasi-3D model is faster, however the applicability of the fully 3D model allows it to extend over a broader range of processes, temporal, and spatial scales.
Time dependent optimal switching controls in online selling models
Bradonjic, Milan; Cohen, Albert
2010-01-01
We present a method to incorporate dishonesty in online selling via a stochastic optimal control problem. In our framework, the seller wishes to maximize her average wealth level W at a fixed time T of her choosing. The corresponding Hamilton-Jacobi-Bellmann (HJB) equation is analyzed for a basic case. For more general models, the admissible control set is restricted to a jump process that switches between extreme values. We propose a new approach, where the optimal control problem is reduced to a multivariable optimization problem.
Time-dependent models of magnetic stars. IV - Perpendicular axes
NASA Astrophysics Data System (ADS)
Moss, David
1987-05-01
The evolution of large-scale initially axisymmetric fields immersed in middle main-sequence stellar models is followed in the case where the rotation axis and initial field axis are strictly perpendicular. The prediction that in this case the surface flux is never buried by the modified Eddington-Sweet circulation is verified, although mode-mixing may eventually reduce the strength of the dipolar field component. It appears that non-axisymmetric field components will grow over time-scales of 108yr or so. Effects of differing initial field geometries are discussed.
NASA Astrophysics Data System (ADS)
Maesano, Francesco E.; D'Ambrogi, Chiara
2017-02-01
We present Vel-IO 3D, a tool for 3D velocity model creation and time-depth conversion, as part of a workflow for 3D model building. The workflow addresses the management of large subsurface dataset, mainly seismic lines and well logs, and the construction of a 3D velocity model able to describe the variation of the velocity parameters related to strong facies and thickness variability and to high structural complexity. Although it is applicable in many geological contexts (e.g. foreland basins, large intermountain basins), it is particularly suitable in wide flat regions, where subsurface structures have no surface expression. The Vel-IO 3D tool is composed by three scripts, written in Python 2.7.11, that automate i) the 3D instantaneous velocity model building, ii) the velocity model optimization, iii) the time-depth conversion. They determine a 3D geological model that is consistent with the primary geological constraints (e.g. depth of the markers on wells). The proposed workflow and the Vel-IO 3D tool have been tested, during the EU funded Project GeoMol, by the construction of the 3D geological model of a flat region, 5700 km2 in area, located in the central part of the Po Plain. The final 3D model showed the efficiency of the workflow and Vel-IO 3D tool in the management of large amount of data both in time and depth domain. A 4 layer-cake velocity model has been applied to a several thousand (5000-13,000 m) thick succession, with 15 horizons from Triassic up to Pleistocene, complicated by a Mesozoic extensional tectonics and by buried thrusts related to Southern Alps and Northern Apennines.
a Fast Method for Measuring the Similarity Between 3d Model and 3d Point Cloud
NASA Astrophysics Data System (ADS)
Zhang, Zongliang; Li, Jonathan; Li, Xin; Lin, Yangbin; Zhang, Shanxin; Wang, Cheng
2016-06-01
This paper proposes a fast method for measuring the partial Similarity between 3D Model and 3D point Cloud (SimMC). It is crucial to measure SimMC for many point cloud-related applications such as 3D object retrieval and inverse procedural modelling. In our proposed method, the surface area of model and the Distance from Model to point Cloud (DistMC) are exploited as measurements to calculate SimMC. Here, DistMC is defined as the weighted distance of the distances between points sampled from model and point cloud. Similarly, Distance from point Cloud to Model (DistCM) is defined as the average distance of the distances between points in point cloud and model. In order to reduce huge computational burdens brought by calculation of DistCM in some traditional methods, we define SimMC as the ratio of weighted surface area of model to DistMC. Compared to those traditional SimMC measuring methods that are only able to measure global similarity, our method is capable of measuring partial similarity by employing distance-weighted strategy. Moreover, our method is able to be faster than other partial similarity assessment methods. We demonstrate the superiority of our method both on synthetic data and laser scanning data.
Nahoon: Time-dependent gas-phase chemical model
NASA Astrophysics Data System (ADS)
Wakelam, V.
2014-09-01
Nahoon is a gas-phase chemical model that computes the chemical evolution in a 1D temperature and density structure. It uses chemical networks downloaded from the KInetic Database for Astrochemistry (KIDA) but the model can be adapted to any network. The program is written in Fortran 90 and uses the DLSODES (double precision) solver from the ODEPACK package to solve the coupled stiff differential equations. The solver computes the chemical evolution of gas-phase species at a fixed temperature and density and can be used in one dimension (1D) if a grid of temperature, density, and visual extinction is provided. Grains, both neutral and negatively charged, and electrons are considered as chemical species and their concentrations are computed at the same time as those of the other species. Nahoon contains a test to check the temperature range of the validity of the rate coefficients and avoid extrapolations outside this range. A test is also included to check for duplication of chemical reactions, defined over complementary ranges of temperature.
Mathematical model of SPOC with a time dependent reactive field
NASA Astrophysics Data System (ADS)
Ohtaki, Masako
2006-03-01
In general the muscle is in one of the two state possible states, relaxation or contraction. These contractions result from relative sliding of myosin and actin in the sarcomere, which is the contraction structure unit of skeletal muscle. The switching between two states is depending on the Ca2+ concentrations. However another state has been detected between these two states. In the third state, that is SPontaneous Oscillatory Contraction (SPOC), sarcomere repeats contraction and extension spontaneously. Muscle fibers are composed of hundreds of sarcomeres in series and one sarcomea also is composed of hundreds of myosin. In microscopic, the force generated by actin and myosin interaction occurs stochastically. SPOC, however, is macroscopically observable and there are regular oscillations. To understand SPOC mechanism, we propose a model for SPOC based on chemical reaction including mechanical process.
2010-06-01
tree models............................................................................ 1 2.2 Extracting and exporting the models...vicinity of RAAF Tindal, Northern Territory [1], while the overall appearance was based on photos of poplar box ( Eucalyptus populnea) from woodlands... Extracting and exporting the models To export the Maya models to MATLAB for further manipulation, a procedure was developed which made use of Z
3D scene modeling from multiple range views
NASA Astrophysics Data System (ADS)
Sequeira, Vitor; Goncalves, Joao G. M.; Ribeiro, M. Isabel
1995-09-01
This paper presents a new 3D scene analysis system that automatically reconstructs the 3D geometric model of real-world scenes from multiple range images acquired by a laser range finder on board of a mobile robot. The reconstruction is achieved through an integrated procedure including range data acquisition, geometrical feature extraction, registration, and integration of multiple views. Different descriptions of the final 3D scene model are obtained: a polygonal triangular mesh, a surface description in terms of planar and biquadratics surfaces, and a 3D boundary representation. Relevant experimental results from the complete 3D scene modeling are presented. Direct applications of this technique include 3D reconstruction and/or update of architectual or industrial plans into a CAD model, design verification of buildings, navigation of autonomous robots, and input to virtual reality systems.
Visualization of 3D Geological Models on Google Earth
NASA Astrophysics Data System (ADS)
Choi, Y.; Um, J.; Park, M.
2013-05-01
Google Earth combines satellite imagery, aerial photography, thematic maps and various data sets to make a three-dimensional (3D) interactive image of the world. Currently, Google Earth is a popular visualization tool in a variety of fields and plays an increasingly important role not only for private users in daily life, but also for scientists, practitioners, policymakers and stakeholders in research and application. In this study, a method to visualize 3D geological models on Google Earth is presented. COLLAborative Design Activity (COLLADA, an open standard XML schema for establishing interactive 3D applications) was used to represent different 3D geological models such as borehole, fence section, surface-based 3D volume and 3D grid by triangle meshes (a set of triangles connected by their common edges or corners). In addition, we designed Keyhole Markup Language (KML, the XML-based scripting language of Google Earth) codes to import the COLLADA files into the 3D render window of Google Earth. The method was applied to the Grosmont formation in Alberta, Canada. The application showed that the combination of COLLADA and KML enables Google Earth to effectively visualize 3D geological structures and properties.; Visualization of the (a) boreholes, (b) fence sections, (c) 3D volume model and (d) 3D grid model of Grossmont formation on Google Earth
3-D Radiative Transfer Modeling of Structured Winds in Massive Hot Stars with Wind3D
NASA Astrophysics Data System (ADS)
Lobel, A.; Toalá, J. A.; Blomme, R.
2011-01-01
We develop 3-D models of the structured winds of massive hot stars with the Wind3D radiative transfer (RT) code. We investigate the physical properties of large-scale structures observed in the wind of the B-type supergiant HD 64760 with detailed line profile fits to Discrete Absorption Components (DACs) and rotational modulations observed with IUE in Si IV λ1395. We develop parameterized input models for Wind3D with large-scale equatorial wind density- and velocity-structures, or so-called `Co-rotating Interaction Regions' (CIRs) and `Rotational Modulation Regions' (RMRs). The parameterized models offer important advantages for high-performance RT calculations over ab-initio hydrodynamic input models. The acceleration of the input model calculations permits us to simulate and investigate a wide variety of physical conditions in the extended winds of massive hot stars. The new modeling method is very flexible for constraining the dynamic and geometric wind properties of RMRs in HD 64760. We compute that the modulations are produced by a regular pattern of radial density enhancements that protrude almost linearly into the equatorial wind. We find that the modulations are caused by narrow `spoke-like' wind regions. We present a hydrodynamic model showing that the linearly shaped radial wind pattern can be caused by mechanical wave action at the base of the stellar wind from the blue supergiant.
A stochastic fault model. 2. Time-dependent case.
Andrews, D.J.
1981-01-01
A random model of fault motion in an earthquake is formulated by assuming that the slip velocity is a random function of position and time truncated at zero, so that it does not have negative values. This random function is chosen to be self-affine; that is, on change of length scale, the function is multiplied by a scale factor but is otherwise unchanged statistically. A snapshot of slip velocity at a given time resembles a cluster of islands with rough topography; the final slip function is a smoother island or cluster of islands. In the Fourier transform domain, shear traction on the fault equals the slip velocity times an impedance function. The fact that this impedance function has a pole at zero frequency implies that traction and slip velocity cannot have the same spectral dependence in space and time. To describe stress fluctuations of the order of 100 bars when smoothed over a length of kilometers and of the order of kilobars at the grain size, shear traction must have a one-dimensional power spectrum is space proportional to the reciprocal wave number. Then the one-dimensional power spectrum for the slip velocity is proportional to the reciprocal wave number squared and for slip to its cube. If slip velocity has the same power law spectrum in time as in space, then the spectrum of ground acceleration with be flat (white noise) both on the fault and in the far field.-Author
A 3D Geometry Model Search Engine to Support Learning
ERIC Educational Resources Information Center
Tam, Gary K. L.; Lau, Rynson W. H.; Zhao, Jianmin
2009-01-01
Due to the popularity of 3D graphics in animation and games, usage of 3D geometry deformable models increases dramatically. Despite their growing importance, these models are difficult and time consuming to build. A distance learning system for the construction of these models could greatly facilitate students to learn and practice at different…
A 3D Geometry Model Search Engine to Support Learning
ERIC Educational Resources Information Center
Tam, Gary K. L.; Lau, Rynson W. H.; Zhao, Jianmin
2009-01-01
Due to the popularity of 3D graphics in animation and games, usage of 3D geometry deformable models increases dramatically. Despite their growing importance, these models are difficult and time consuming to build. A distance learning system for the construction of these models could greatly facilitate students to learn and practice at different…
[Potentials of 3D-modeling in reconstructive orbital surgery].
Butsan, S B; Khokhlachev, S B; Ĭigitaliev, Sh N; Zaiakin, Ia A
2012-01-01
A technique of bone reconstructive surgery of orbitofrontonasomalar region using 3D-modeling based on multispiral computer tomography data is presented. The efficacy of intraoperative templates created using 3D-modeling was showed for harvesting and modeling of bone calvarial autografts. The steps of reconstructive procedure are explained in details for repair of medial and inferior orbital fractures.
Hybrid modeling of time-dependent solar wind-comet interactions
NASA Astrophysics Data System (ADS)
Alho, Markku; Wedlund, Cyril Simon; Kallio, Esa; Nilsson, Hans
2016-04-01
Global hybrid plasma modelling of cometary environments is an essential tool in understanding the global implications of point measurements performed by the Rosetta probe in the vicinity of 67P/Churyumov-Gerasimenko. A 3-D, global hybrid plasma model, including the effects of plasma-driven ionization of cometary neutrals, has been employed to model an approximation of 67P's environment around perihelion conditions. Model inputs include solar wind upstream parameters, a simple cometary neutral model and a H2O+-bound photochemistry. In this work we present results on the responses of a cometary plasma environment when impinged upon by a time-dependent solar wind. Stepwise upward and downward density changes as well as linear ramps are investigated, along with tangential discontinuities in the interplanetary magnetic field. As the production rates of cometary ions are coupled to solar wind parameters through e.g. charge exchange and electron impact ionization, solar wind variations create non-trivial transient phenomena in the cometary environment. Implications for CME impacts and tail disconnection events are explored, giving insight on how these events may appear in the observational datasets (magnetometer, ion spectrometer) from past missions and from Rosetta.
Computational modeling of RNA 3D structures and interactions.
Dawson, Wayne K; Bujnicki, Janusz M
2016-04-01
RNA molecules have key functions in cellular processes beyond being carriers of protein-coding information. These functions are often dependent on the ability to form complex three-dimensional (3D) structures. However, experimental determination of RNA 3D structures is difficult, which has prompted the development of computational methods for structure prediction from sequence. Recent progress in 3D structure modeling of RNA and emerging approaches for predicting RNA interactions with ions, ligands and proteins have been stimulated by successes in protein 3D structure modeling. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling
Lovell, Nigel H.; Dokos, Socrates
2013-01-01
A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN), intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue. PMID:23935704
San Francisco Bay test case for 3-D model verification
Smith, Peter E.
1994-01-01
This paper describes a field test case for 3-D hydrodynamic model verification using data from Carquinez Strait in San Francisco Bay, California. It will be disseminated by the ASCE Computational Hydraulics task committee on 3-D Free-Surface Hydrodynamic Model Verifications during late 1994.
Complex crustal structures: their 3D grav/mag modelling and 3D printing
NASA Astrophysics Data System (ADS)
Götze, Hans-Jürgen; Schmidt, Sabine; Menzel, Peter
2017-04-01
Our new techniques for modelling and visualization are user-friendly because they are highly interactive, ideally real-time and topology conserving and can be used for both flat and spherical models in 3D. These are important requirements for joint inversion for gravity and magnetic modelling of fields and their derivatives, constrained by seismic and structural input from independent data sources. A borehole tool for magnetic and gravity modelling will also be introduced. We are already close to satisfying the demand of treating several geophysical methods in a single model for subsurface evaluation purposes and aim now for fulfilling most of the constraints: consistency of modelling results and measurements and geological plausibility as well. For 3D modelling, polyhedrons built by triangles are used. All elements of the gravity and magnetic tensors can be included. In the modelling interface, after geometry changes the effect on the model is quickly updated because only the changed triangles have to be recalculated. Because of the triangular model structure, our approach can handle complex structures very well and flexible (e.g. overhangs of salt domes or plumes). For regional models, the use of spherical geometries and calculations is necessary and available. 3D visualization is performed with a 3D-printer (Ultimaker 2) and gives new insights into even rather complicated Earth subsurface structures. Inversion can either be run over the whole model, but typically it is used in smaller parts of the model, helping to solve local problems and/or proving/disproving local hypotheses. The basic principles behind this interactive approach are high performance optimized algorithms (CMA-ES: Covariance-matrix-adoption-evolution-strategy). The efficiency of the algorithm is rather good in terms of stable convergence due to topological model validity. Potential field modelling is always influenced by edge effects. To avoid this, a simple but very robust method has been
Interactive mapping on 3-D terrain models
NASA Astrophysics Data System (ADS)
Bernardin, T.; Cowgill, E.; Gold, R.; Hamann, B.; Kreylos, O.; Schmitt, A.
2006-10-01
We present an interactive, real-time mapping system for use with digital elevation models and remotely sensed multispectral imagery that aids geoscientists in the creation and interpretation of geologic/neotectonic maps at length scales of 10 m to 1000 km. Our system provides a terrain visualization of the surface of the Earth or other terrestrial planets by displaying a virtual terrain model generated from a digital elevation model overlain by a color texture generated from orthophotos or satellite imagery. We use a quadtree-based, multiresolution display method to render in real time high-resolution virtual terrain models that span large spatial regions. The system allows users to measure the orientations of geologic surfaces and record their observations by drawing lines directly on the virtual terrain model. In addition, interpretive surfaces can be generated from these drawings and displayed to facilitate understanding of the three-dimensional geometry of geologic surfaces. The main strength of our system is the combination of real-time rendering and interactive mapping performed directly on the virtual terrain model with the ability to navigate the scene while changing viewpoints arbitrarily during mapping. User studies and comparisons with commercially available mapping software show that our system improves mapping accuracy and efficiency and also yields observations that cannot be made with existing systems.
3D Modelling of Urban Terrain (Modelisation 3D de milieu urbain)
2011-09-01
NORTH ATLANTIC TREATY ORGANISATION RESEARCH AND TECHNOLOGY ORGANISATION AC/323(SET-118)TP/393 www.rto.nato.int RTO TECHNICAL REPORT TR...Distribution and Availability on Back Cover I -~w I NORTH ATLANTIC TREATY ORGANISATION RESEARCH AND...TECHNOLOGY ORGANISATION AC/323(SET-118)TP/393 www.rto.nato.int RTO TECHNICAL REPORT TR-SET-118 3D Modelling of Urban Terrain
3-D model-based Bayesian classification
Soenneland, L.; Tenneboe, P.; Gehrmann, T.; Yrke, O.
1994-12-31
The challenging task of the interpreter is to integrate different pieces of information and combine them into an earth model. The sophistication level of this earth model might vary from the simplest geometrical description to the most complex set of reservoir parameters related to the geometrical description. Obviously the sophistication level also depend on the completeness of the available information. The authors describe the interpreter`s task as a mapping between the observation space and the model space. The information available to the interpreter exists in observation space and the task is to infer a model in model-space. It is well-known that this inversion problem is non-unique. Therefore any attempt to find a solution depend son constraints being added in some manner. The solution will obviously depend on which constraints are introduced and it would be desirable to allow the interpreter to modify the constraints in a problem-dependent manner. They will present a probabilistic framework that gives the interpreter the tools to integrate the different types of information and produce constrained solutions. The constraints can be adapted to the problem at hand.
Opportunity Landing Spot Panorama (3-D Model)
NASA Technical Reports Server (NTRS)
2004-01-01
The rocky outcrop traversed by the Mars Exploration Rover Opportunity is visible in this three-dimensional model of the rover's landing site. Opportunity has acquired close-up images along the way, and scientists are using the rover's instruments to closely examine portions of interest. The white fragments that look crumpled near the center of the image are portions of the airbags. Distant scenery is displayed on a spherical backdrop or 'billboard' for context. Artifacts near the top rim of the crater are a result of the transition between the three-dimensional model and the billboard. Portions of the terrain model lacking sufficient data appear as blank spaces or gaps, colored reddish-brown for better viewing. This image was generated using special software from NASA's Ames Research Center and a mosaic of images taken by the rover's panoramic camera.
[figure removed for brevity, see original site] Click on image for larger view
The rocky outcrop traversed by the Mars Exploration Rover Opportunity is visible in this zoomed-in portion of a three-dimensional model of the rover's landing site. Opportunity has acquired close-up images along the way, and scientists are using the rover's instruments to closely examine portions of interest. The white fragments that look crumpled near the center of the image are portions of the airbags. Distant scenery is displayed on a spherical backdrop or 'billboard' for context. Artifacts near the top rim of the crater are a result of the transition between the three-dimensional model and the billboard. Portions of the terrain model lacking sufficient data appear as blank spaces or gaps, colored reddish-brown for better viewing. This image was generated using special software from NASA's Ames Research Center and a mosaic of images taken by the rover's panoramic camera.
An Automated 3d Indoor Topological Navigation Network Modelling
NASA Astrophysics Data System (ADS)
Jamali, A.; Rahman, A. A.; Boguslawski, P.; Gold, C. M.
2015-10-01
Indoor navigation is important for various applications such as disaster management and safety analysis. In the last decade, indoor environment has been a focus of wide research; that includes developing techniques for acquiring indoor data (e.g. Terrestrial laser scanning), 3D indoor modelling and 3D indoor navigation models. In this paper, an automated 3D topological indoor network generated from inaccurate 3D building models is proposed. In a normal scenario, 3D indoor navigation network derivation needs accurate 3D models with no errors (e.g. gap, intersect) and two cells (e.g. rooms, corridors) should touch each other to build their connections. The presented 3D modeling of indoor navigation network is based on surveying control points and it is less dependent on the 3D geometrical building model. For reducing time and cost of indoor building data acquisition process, Trimble LaserAce 1000 as surveying instrument is used. The modelling results were validated against an accurate geometry of indoor building environment which was acquired using Trimble M3 total station.
An Automatic Registration Algorithm for 3D Maxillofacial Model
NASA Astrophysics Data System (ADS)
Qiu, Luwen; Zhou, Zhongwei; Guo, Jixiang; Lv, Jiancheng
2016-09-01
3D image registration aims at aligning two 3D data sets in a common coordinate system, which has been widely used in computer vision, pattern recognition and computer assisted surgery. One challenging problem in 3D registration is that point-wise correspondences between two point sets are often unknown apriori. In this work, we develop an automatic algorithm for 3D maxillofacial models registration including facial surface model and skull model. Our proposed registration algorithm can achieve a good alignment result between partial and whole maxillofacial model in spite of ambiguous matching, which has a potential application in the oral and maxillofacial reparative and reconstructive surgery. The proposed algorithm includes three steps: (1) 3D-SIFT features extraction and FPFH descriptors construction; (2) feature matching using SAC-IA; (3) coarse rigid alignment and refinement by ICP. Experiments on facial surfaces and mandible skull models demonstrate the efficiency and robustness of our algorithm.
Scalable singular 3D modeling for digital battlefield applications
NASA Astrophysics Data System (ADS)
Jannson, Tomasz P.; Ternovskiy, Igor V.
2000-10-01
We propose a new classification algorithm to detect and classify targets of interest. It is based on an advanced brand of analytic geometry of manifolds, called theory of catastrophes. Physical Optics Corporation's (POC) scalable 3D model representation provides automatic and real-time analysis of a discrete frame of a sensed 2D imagery of terrain, urban, and target features. It then transforms this frame of discrete different-perspective 2D views of a target into a 3D continuous model called a pictogram. The unique local stereopsis feature of this modeling is the surprising ability to locally obtain a 3D pictogram from a single monoscopic photograph. The proposed 3D modeling, combined with more standard change detection algorithms and 3D terrain feature models, will constitute a novel classification algorithm and a new type of digital battlefield imagery for Imaging Systems.
Venusian Applications of 3D Convection Modeling
NASA Technical Reports Server (NTRS)
Bonaccorso, Timary Annie
2011-01-01
This study models mantle convection on Venus using the 'cubed sphere' code OEDIPUS, which models one-sixth of the planet in spherical geometry. We are attempting to balance internal heating, bottom mantle viscosity, and temperature difference across Venus' mantle, in order to create a realistic model that matches with current planetary observations. We also have begun to run both lower and upper mantle simulations to determine whether layered (as opposed to whole-mantle) convection might produce more efficient heat transfer, as well as to model coronae formation in the upper mantle. Upper mantle simulations are completed using OEDIPUS' Cartesian counterpart, JOCASTA. This summer's central question has been how to define a mantle plume. Traditionally, we have defined a hot plume the region with temperature at or above 40% of the difference between the maximum and horizontally averaged temperature, and a cold plume as the region with 40% of the difference between the minimum and average temperature. For less viscous cases (1020 Pa?s), the plumes generated by that definition lacked vigor, displaying buoyancies 1/100th of those found in previous, higher viscosity simulations (1021 Pa?s). As the mantle plumes with large buoyancy flux are most likely to produce topographic uplift and volcanism, the low viscosity cases' plumes may not produce observable deformation. In an effort to eliminate the smallest plumes, we experimented with different lower bound parameters and temperature percentages.
James E. Fisher; Cliff B. Davis; Walter L. Weaver
2005-06-01
A compressor model has been implemented in the RELAP5-3D© code. The model is similar to that of the existing pump model, and performs the same function on a gas as the pump performs on a single-phase or two-phase fluid. The compressor component consists of an inlet junction and a control volume, and optionally, an outlet junction. This feature permits cascading compressor components in series. The equations describing the physics of the compressor are derived from first principles. These equations are used to obtain the head, the torque, and the energy dissipation. Compressor performance is specified using a map, specific to the design of the machine, in terms of the ratio of outlet-to-inlet total (or stagnation) pressure and adiabatic efficiency as functions of rotational velocity and flow rate. The input quantities are specified in terms of dimensionless variables, which are corrected to stagnation density and stagnation sound speed. A small correction was formulated for the input of efficiency to account for the error introduced by assumption of constant density when integrating the momentum equation. Comparison of the results of steady-state operation of the compressor model to those of the MIT design calculation showed excellent agreement for both pressure ratio and power.
Venusian Applications of 3D Convection Modeling
NASA Technical Reports Server (NTRS)
Bonaccorso, Timary Annie
2011-01-01
This study models mantle convection on Venus using the 'cubed sphere' code OEDIPUS, which models one-sixth of the planet in spherical geometry. We are attempting to balance internal heating, bottom mantle viscosity, and temperature difference across Venus' mantle, in order to create a realistic model that matches with current planetary observations. We also have begun to run both lower and upper mantle simulations to determine whether layered (as opposed to whole-mantle) convection might produce more efficient heat transfer, as well as to model coronae formation in the upper mantle. Upper mantle simulations are completed using OEDIPUS' Cartesian counterpart, JOCASTA. This summer's central question has been how to define a mantle plume. Traditionally, we have defined a hot plume the region with temperature at or above 40% of the difference between the maximum and horizontally averaged temperature, and a cold plume as the region with 40% of the difference between the minimum and average temperature. For less viscous cases (1020 Pa?s), the plumes generated by that definition lacked vigor, displaying buoyancies 1/100th of those found in previous, higher viscosity simulations (1021 Pa?s). As the mantle plumes with large buoyancy flux are most likely to produce topographic uplift and volcanism, the low viscosity cases' plumes may not produce observable deformation. In an effort to eliminate the smallest plumes, we experimented with different lower bound parameters and temperature percentages.
NASA Astrophysics Data System (ADS)
Yu, H.-S.; Jackson, B. V.; Hick, P. P.; Buffington, A.; Odstrcil, D.; Wu, C.-C.; Davies, J. A.; Bisi, M. M.; Tokumaru, M.
2015-09-01
The University of California, San Diego, time-dependent analyses of the heliosphere provide three-dimensional (3D) reconstructions of solar wind velocities and densities from observations of interplanetary scintillation (IPS). Using data from the Solar-Terrestrial Environment Laboratory, Japan, these reconstructions provide a real-time prediction of the global solar-wind density and velocity throughout the whole heliosphere with a temporal cadence of about one day (ips.ucsd.edu). Updates to this modeling effort continue: in the present article, near-Sun results extracted from the time-dependent 3D reconstruction are used as inner boundary conditions to drive 3D-MHD models ( e.g. ENLIL and H3D-MHD). This allows us to explore the differences between the IPS kinematic-model data-fitting procedure and current 3D-MHD modeling techniques. The differences in these techniques provide interesting insights into the physical principles governing the expulsion of coronal mass ejections (CMEs). Here we detail for the first time several specific CMEs and an induced shock that occurred in September 2011 that demonstrate some of the issues resulting from these analyses.
Extending 3D city models with legal information
NASA Astrophysics Data System (ADS)
Frank, A. U.; Fuhrmann, T.; Navratil, G.
2012-10-01
3D city models represent existing physical objects and their topological and functional relations. In everyday life the rights and responsibilities connected to these objects, primarily legally defined rights and obligations but also other socially and culturally established rights, are of importance. The rights and obligations are defined in various laws and it is often difficult to identify the rules applicable for a certain case. The existing 2D cadastres show civil law rights and obligations and plans to extend them to provide information about public law restrictions for land use are in several countries under way. It is tempting to design extensions to the 3D city models to provide information about legal rights in 3D. The paper analyses the different types of information that are needed to reduce conflicts and to facilitate decisions about land use. We identify the role 3D city models augmented with planning information in 3D can play, but do not advocate a general conversion from 2D to 3D for the legal cadastre. Space is not anisotropic and the up/down dimension is practically very different from the two dimensional plane - this difference must be respected when designing spatial information systems. The conclusions are: (1) continue the current regime for ownership of apartments, which is not ownership of a 3D volume, but co-ownership of a building with exclusive use of some rooms; such exclusive use rights could be shown in a 3D city model; (2) ownership of 3D volumes for complex and unusual building situations can be reported in a 3D city model, but are not required everywhere; (3) indicate restrictions for land use and building in 3D city models, with links to the legal sources.
Global Magnetospheric Modeling of 3D Reconnection
NASA Technical Reports Server (NTRS)
Spicer, Daniel S.
1999-01-01
A review of approaches to the global modeling of the terrestrial magnetosphere, how these approaches are utilized to interpret satellite data, and how these approaches have been successful at predicting magnetospheric phenomena will be presented. In addition, the importance of the ionospheric boundary and its effect on the globally topology of the magnetospheric magnetic field will be reviewed. In particular, numerical results that are rapidly changing our view of magnetospheric reconnection within the magnetospheric magnetic field will be discussed.
Global Magnetospheric Modeling of 3D Reconnection
NASA Technical Reports Server (NTRS)
Spicer, Daniel S.
1999-01-01
A review of approaches to the global modeling of the terrestrial magnetosphere, how these approaches are utilized to interpret satellite data, and how these approaches have been successful at predicting magnetospheric phenomena will be presented. In addition, the importance of the ionospheric boundary and its effect on the globally topology of the magnetospheric magnetic field will be reviewed. In particular, numerical results that are rapidly changing our view of magnetospheric reconnection within the magnetospheric magnetic field will be discussed.
Modelling Polymer Deformation during 3D Printing
NASA Astrophysics Data System (ADS)
McIlroy, Claire; Olmsted, Peter
Three-dimensional printing has the potential to transform manufacturing processes, yet improving the strength of printed parts, to equal that of traditionally-manufactured parts, remains an underlying issue. The fused deposition modelling technique involves melting a thermoplastic, followed by layer-by-layer extrusion to fabricate an object. The key to ensuring strength at the weld between layers is successful inter-diffusion. However, prior to welding, both the extrusion process and the cooling temperature profile can significantly deform the polymer micro-structure and, consequently, how well the polymers are able to ``re-entangle'' across the weld. In particular, polymer alignment in the flow can cause de-bonding of the layers and create defects. We have developed a simple model of the non-isothermal extrusion process to explore the effects that typical printing conditions and material rheology have on the conformation of a polymer melt. In particular, we incorporate both stretch and orientation using the Rolie-Poly constitutive equation to examine the melt structure as it flows through the nozzle, the subsequent alignment with the build plate and the resulting deformation due to the fixed nozzle height, which is typically less than the nozzle radius.
Modeling 3D Facial Shape from DNA
Claes, Peter; Liberton, Denise K.; Daniels, Katleen; Rosana, Kerri Matthes; Quillen, Ellen E.; Pearson, Laurel N.; McEvoy, Brian; Bauchet, Marc; Zaidi, Arslan A.; Yao, Wei; Tang, Hua; Barsh, Gregory S.; Absher, Devin M.; Puts, David A.; Rocha, Jorge; Beleza, Sandra; Pereira, Rinaldo W.; Baynam, Gareth; Suetens, Paul; Vandermeulen, Dirk; Wagner, Jennifer K.; Boster, James S.; Shriver, Mark D.
2014-01-01
Human facial diversity is substantial, complex, and largely scientifically unexplained. We used spatially dense quasi-landmarks to measure face shape in population samples with mixed West African and European ancestry from three locations (United States, Brazil, and Cape Verde). Using bootstrapped response-based imputation modeling (BRIM), we uncover the relationships between facial variation and the effects of sex, genomic ancestry, and a subset of craniofacial candidate genes. The facial effects of these variables are summarized as response-based imputed predictor (RIP) variables, which are validated using self-reported sex, genomic ancestry, and observer-based facial ratings (femininity and proportional ancestry) and judgments (sex and population group). By jointly modeling sex, genomic ancestry, and genotype, the independent effects of particular alleles on facial features can be uncovered. Results on a set of 20 genes showing significant effects on facial features provide support for this approach as a novel means to identify genes affecting normal-range facial features and for approximating the appearance of a face from genetic markers. PMID:24651127
Modeling 3D facial shape from DNA.
Claes, Peter; Liberton, Denise K; Daniels, Katleen; Rosana, Kerri Matthes; Quillen, Ellen E; Pearson, Laurel N; McEvoy, Brian; Bauchet, Marc; Zaidi, Arslan A; Yao, Wei; Tang, Hua; Barsh, Gregory S; Absher, Devin M; Puts, David A; Rocha, Jorge; Beleza, Sandra; Pereira, Rinaldo W; Baynam, Gareth; Suetens, Paul; Vandermeulen, Dirk; Wagner, Jennifer K; Boster, James S; Shriver, Mark D
2014-03-01
Human facial diversity is substantial, complex, and largely scientifically unexplained. We used spatially dense quasi-landmarks to measure face shape in population samples with mixed West African and European ancestry from three locations (United States, Brazil, and Cape Verde). Using bootstrapped response-based imputation modeling (BRIM), we uncover the relationships between facial variation and the effects of sex, genomic ancestry, and a subset of craniofacial candidate genes. The facial effects of these variables are summarized as response-based imputed predictor (RIP) variables, which are validated using self-reported sex, genomic ancestry, and observer-based facial ratings (femininity and proportional ancestry) and judgments (sex and population group). By jointly modeling sex, genomic ancestry, and genotype, the independent effects of particular alleles on facial features can be uncovered. Results on a set of 20 genes showing significant effects on facial features provide support for this approach as a novel means to identify genes affecting normal-range facial features and for approximating the appearance of a face from genetic markers.
Virtual 3d City Modeling: Techniques and Applications
NASA Astrophysics Data System (ADS)
Singh, S. P.; Jain, K.; Mandla, V. R.
2013-08-01
3D city model is a digital representation of the Earth's surface and it's related objects such as Building, Tree, Vegetation, and some manmade feature belonging to urban area. There are various terms used for 3D city models such as "Cybertown", "Cybercity", "Virtual City", or "Digital City". 3D city models are basically a computerized or digital model of a city contains the graphic representation of buildings and other objects in 2.5 or 3D. Generally three main Geomatics approach are using for Virtual 3-D City models generation, in first approach, researcher are using Conventional techniques such as Vector Map data, DEM, Aerial images, second approach are based on High resolution satellite images with LASER scanning, In third method, many researcher are using Terrestrial images by using Close Range Photogrammetry with DSM & Texture mapping. We start this paper from the introduction of various Geomatics techniques for 3D City modeling. These techniques divided in to two main categories: one is based on Automation (Automatic, Semi-automatic and Manual methods), and another is Based on Data input techniques (one is Photogrammetry, another is Laser Techniques). After details study of this, finally in short, we are trying to give the conclusions of this study. In the last, we are trying to give the conclusions of this research paper and also giving a short view for justification and analysis, and present trend for 3D City modeling. This paper gives an overview about the Techniques related with "Generation of Virtual 3-D City models using Geomatics Techniques" and the Applications of Virtual 3D City models. Photogrammetry, (Close range, Aerial, Satellite), Lasergrammetry, GPS, or combination of these modern Geomatics techniques play a major role to create a virtual 3-D City model. Each and every techniques and method has some advantages and some drawbacks. Point cloud model is a modern trend for virtual 3-D city model. Photo-realistic, Scalable, Geo-referenced virtual 3
3D PIC Modeling of Microcavity Discharge
NASA Astrophysics Data System (ADS)
Hopkins, Matthew; Manginell, Ronald; Moore, Christopher; Yee, Benjamin; Moorman, Matthew
2015-09-01
We present a number of techniques and challenges in simulating the transient behavior of a microcavity discharge. Our microcavities are typically cylindrical with diameters approximately 50 - 100 μm, heights of 50 - 200 μm, pressure near atmospheric, and operate at a few hundred volts. We employ a fully kinetic simulation methodology, the Particle-in-Cell (PIC) method, with interparticle collisions handled via methods based on direct simulation Monte Carlo (DSMC). In particular, we explicitly include kinetic electrons. Some of the challenges we encounter include variations in number densities, external circuit coupling, and time step resolution constraints. By employing dynamic particle weighting (particle weights vary over time by species and location) we can mitigate some of the challenges modeling systems with 107 variations in number densities. Smoothing mechanisms have been used to attempt to mitigate external circuit response. We perform our simulations on hundreds or thousands of processing cores to accommodate the computational work inherent in using relatively small time step sizes (e.g., 50 fs for a 100 ns calculation). In addition, particle weighting issues inherent to three-dimensional low temperature plasma systems will be mentioned. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under Contract DE-AC04-94AL85000.
NASA Astrophysics Data System (ADS)
Przyborska, Anna; Kosecki, Szymon; Jakacki, Jaromir
2014-05-01
Kongsfjorden is a West Svalbard fjord with a surface area of about 210 km2. It is obvious that the depths of the outer and central basins are influenced by the open sea, under influence of West Spitsbergen Current (WSC), which curry out warm Atlantic water and cold East Spitsbergen Current, while the shallower, inner basin has a large glacial outflow and its maximum depths do not exceed 100 m. Freshwater stored in Spitsbergen glaciers have strong influence on local hydrology and physical fjord conditions. Both, local and shelf conditions have impact on state of the fjord. External forces like tides, velocities at the boundary and atmospheric forces together with sources of cold and dens fresh water in the fjords will give reliable representation of physical conditions in Kongsfjorden. Modeling could help to solve this problem and we have hope that we find answer which one is the most important for local conditions in fjord. Calculations of balances between cold fresh water and warm and salt will provide additional information that could help to answer the main question of the GAME (Growing of the Arctic Marine Ecosystem) project - what is the reaction of physically controlled Arctic marine ecosystem to temperature rise.
Image based 3D city modeling : Comparative study
NASA Astrophysics Data System (ADS)
Singh, S. P.; Jain, K.; Mandla, V. R.
2014-06-01
3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing rapidly for various engineering and non-engineering applications. Generally four main image based approaches were used for virtual 3D city models generation. In first approach, researchers were used Sketch based modeling, second method is Procedural grammar based modeling, third approach is Close range photogrammetry based modeling and fourth approach is mainly based on Computer Vision techniques. SketchUp, CityEngine, Photomodeler and Agisoft Photoscan are the main softwares to represent these approaches respectively. These softwares have different approaches & methods suitable for image based 3D city modeling. Literature study shows that till date, there is no complete such type of comparative study available to create complete 3D city model by using images. This paper gives a comparative assessment of these four image based 3D modeling approaches. This comparative study is mainly based on data acquisition methods, data processing techniques and output 3D model products. For this research work, study area is the campus of civil engineering department, Indian Institute of Technology, Roorkee (India). This 3D campus acts as a prototype for city. This study also explains various governing parameters, factors and work experiences. This research work also gives a brief introduction, strengths and weakness of these four image based techniques. Some personal comment is also given as what can do or what can't do from these softwares. At the last, this study shows; it concluded that, each and every software has some advantages and limitations. Choice of software depends on user requirements of 3D project. For normal visualization project, SketchUp software is a good option. For 3D documentation record, Photomodeler gives good result. For Large city
NoSQL Based 3D City Model Management System
NASA Astrophysics Data System (ADS)
Mao, B.; Harrie, L.; Cao, J.; Wu, Z.; Shen, J.
2014-04-01
To manage increasingly complicated 3D city models, a framework based on NoSQL database is proposed in this paper. The framework supports import and export of 3D city model according to international standards such as CityGML, KML/COLLADA and X3D. We also suggest and implement 3D model analysis and visualization in the framework. For city model analysis, 3D geometry data and semantic information (such as name, height, area, price and so on) are stored and processed separately. We use a Map-Reduce method to deal with the 3D geometry data since it is more complex, while the semantic analysis is mainly based on database query operation. For visualization, a multiple 3D city representation structure CityTree is implemented within the framework to support dynamic LODs based on user viewpoint. Also, the proposed framework is easily extensible and supports geoindexes to speed up the querying. Our experimental results show that the proposed 3D city management system can efficiently fulfil the analysis and visualization requirements.
Modeling cell migration in 3D: Status and challenges.
Rangarajan, Rajagopal; Zaman, Muhammad H
2008-01-01
Cell migration is a multi-scale process that integrates signaling, mechanics and biochemical reaction kinetics. Various mathematical models accurately predict cell migration on 2D surfaces, but are unable to capture the complexities of 3D migration. Additionally, quantitative 3D cell migration models have been few and far between. In this review we look and characterize various mathematical models available in literature to predict cell migration in 3D matrices and analyze their strengths and possible changes to these models that could improve their predictive capabilities.
3D model retrieval method based on mesh segmentation
NASA Astrophysics Data System (ADS)
Gan, Yuanchao; Tang, Yan; Zhang, Qingchen
2012-04-01
In the process of feature description and extraction, current 3D model retrieval algorithms focus on the global features of 3D models but ignore the combination of global and local features of the model. For this reason, they show less effective performance to the models with similar global shape and different local shape. This paper proposes a novel algorithm for 3D model retrieval based on mesh segmentation. The key idea is to exact the structure feature and the local shape feature of 3D models, and then to compares the similarities of the two characteristics and the total similarity between the models. A system that realizes this approach was built and tested on a database of 200 objects and achieves expected results. The results show that the proposed algorithm improves the precision and the recall rate effectively.
Bioprinted 3D vascularized tissue model for drug toxicity analysis.
Massa, Solange; Sakr, Mahmoud Ahmed; Seo, Jungmok; Bandaru, Praveen; Arneri, Andrea; Bersini, Simone; Zare-Eelanjegh, Elaheh; Jalilian, Elmira; Cha, Byung-Hyun; Antona, Silvia; Enrico, Alessandro; Gao, Yuan; Hassan, Shabir; Acevedo, Juan Pablo; Dokmeci, Mehmet R; Zhang, Yu Shrike; Khademhosseini, Ali; Shin, Su Ryon
2017-07-01
To develop biomimetic three-dimensional (3D) tissue constructs for drug screening and biological studies, engineered blood vessels should be integrated into the constructs to mimic the drug administration process in vivo. The development of perfusable vascularized 3D tissue constructs for studying the drug administration process through an engineered endothelial layer remains an area of intensive research. Here, we report the development of a simple 3D vascularized liver tissue model to study drug toxicity through the incorporation of an engineered endothelial layer. Using a sacrificial bioprinting technique, a hollow microchannel was successfully fabricated in the 3D liver tissue construct created with HepG2/C3A cells encapsulated in a gelatin methacryloyl hydrogel. After seeding human umbilical vein endothelial cells (HUVECs) into the microchannel, we obtained a vascularized tissue construct containing a uniformly coated HUVEC layer within the hollow microchannel. The inclusion of the HUVEC layer into the scaffold resulted in delayed permeability of biomolecules into the 3D liver construct. In addition, the vascularized construct containing the HUVEC layer showed an increased viability of the HepG2/C3A cells within the 3D scaffold compared to that of the 3D liver constructs without the HUVEC layer, demonstrating a protective role of the introduced endothelial cell layer. The 3D vascularized liver model presented in this study is anticipated to provide a better and more accurate in vitro liver model system for future drug toxicity testing.
Comparison between two models of absorption of matter waves by a thin time-dependent barrier
NASA Astrophysics Data System (ADS)
Barbier, Maximilien; Beau, Mathieu; Goussev, Arseni
2015-11-01
We report a quantitative, analytical, and numerical comparison between two models of the interaction of a nonrelativistic quantum particle with a thin time-dependent absorbing barrier. The first model represents the barrier by a set of time-dependent discontinuous matching conditions, which are closely related to Kottler boundary conditions used in stationary-wave optics as a mathematical basis for Kirchhoff diffraction theory. The second model mimics the absorbing barrier with an off-diagonal δ potential with a time-dependent amplitude. We show that the two models of absorption agree in their predictions in a semiclassical regime, the regime readily accessible in modern experiments with ultracold atoms.
Photograph-based 3D modeling in an educational system
NASA Astrophysics Data System (ADS)
Ohgashi, Hitoshi; Itoh, Yuki; Shibayama, Jun-Ichi
1996-03-01
In this paper, we describe a method of 3D modeling based on photographs for real-time graphics system of educational use. The method uses few basic models like squares, spheres and so on, and a 3D model is constructed by modifying basic models, guided by parameters. For example, we made an educational real-time graphics system of the deep space, having galaxies' 3D models. A typical galaxy called spiral galaxy consists of two parts; a spherical center part named bulge, and a whirlpool convex-lens shaped surrounding part named galactic disc. Galaxies' photographs are taken from a limited angle, because they are too far away, and viewed only from the earth. So a galaxies' photograph is whether in a whirlpool form, a convex-lens form, or in a slant form between the two forms. Therefore our method puts a sphere model at the bulge position, and a convex-lens model formed by a sphere metamorphism at the galactic disc position. Parameters are used to change galaxies' position, size, XYZ-axes metamorphism and rotation. Thus we get a 3D galaxy model corresponding to the photograph, and learners can look at a 3D galaxy from any viewpoint and view direction. In this way, we construct realistic 3D models. The amount of rendering computation is still low. Thus real-time rendering images are produced freely from a moving viewpoint and view direction.
Dalir, Nemat
2014-01-01
An exact analytical solution is obtained for the problem of three-dimensional transient heat conduction in the multilayered sphere. The sphere has multiple layers in the radial direction and, in each layer, time-dependent and spatially nonuniform volumetric internal heat sources are considered. To obtain the temperature distribution, the eigenfunction expansion method is used. An arbitrary combination of homogenous boundary condition of the first or second kind can be applied in the angular and azimuthal directions. Nevertheless, solution is valid for nonhomogeneous boundary conditions of the third kind (convection) in the radial direction. A case study problem for the three-layer quarter-spherical region is solved and the results are discussed.
Dalir, Nemat
2014-01-01
An exact analytical solution is obtained for the problem of three-dimensional transient heat conduction in the multilayered sphere. The sphere has multiple layers in the radial direction and, in each layer, time-dependent and spatially nonuniform volumetric internal heat sources are considered. To obtain the temperature distribution, the eigenfunction expansion method is used. An arbitrary combination of homogenous boundary condition of the first or second kind can be applied in the angular and azimuthal directions. Nevertheless, solution is valid for nonhomogeneous boundary conditions of the third kind (convection) in the radial direction. A case study problem for the three-layer quarter-spherical region is solved and the results are discussed. PMID:27433511
High Resolution 3d Modeling of the Behaim Globe
NASA Astrophysics Data System (ADS)
Menna, F.; Rizzi, A.; Nocerino, E.; Remondino, F.; Gruen, A.
2012-07-01
The article describes the 3D surveying and modeling of the Behaim globe, the oldest still existing and intact globe of the earth, preserved at the German National Museum of Nuremberg, Germany. The work is primarily performed using high-resolution digital images and automatic photogrammetric techniques. Triangulation-based laser scanning is also employed to fill some gaps in the derived image-based 3D geometry and perform geometric comparisons. Major problems are encountered in texture mapping. The 3D modeling project and the creation of high-resolution map-projections is performed for scientific, conservation, visualization and education purposes.
3D-model building of the jaw impression
NASA Astrophysics Data System (ADS)
Ahmed, Moumen T.; Yamany, Sameh M.; Hemayed, Elsayed E.; Farag, Aly A.
1997-03-01
A novel approach is proposed to obtain a record of the patient's occlusion using computer vision. Data acquisition is obtained using intra-oral video cameras. The technique utilizes shape from shading to extract 3D information from 2D views of the jaw, and a novel technique for 3D data registration using genetic algorithms. The resulting 3D model can be used for diagnosis, treatment planning, and implant purposes. The overall purpose of this research is to develop a model-based vision system for orthodontics to replace traditional approaches. This system will be flexible, accurate, and will reduce the cost of orthodontic treatments.
3D model-based still image object categorization
NASA Astrophysics Data System (ADS)
Petre, Raluca-Diana; Zaharia, Titus
2011-09-01
This paper proposes a novel recognition scheme algorithm for semantic labeling of 2D object present in still images. The principle consists of matching unknown 2D objects with categorized 3D models in order to infer the semantics of the 3D object to the image. We tested our new recognition framework by using the MPEG-7 and Princeton 3D model databases in order to label unknown images randomly selected from the web. Results obtained show promising performances, with recognition rate up to 84%, which opens interesting perspectives in terms of semantic metadata extraction from still images/videos.
Summary on several key techniques in 3D geological modeling.
Mei, Gang
2014-01-01
Several key techniques in 3D geological modeling including planar mesh generation, spatial interpolation, and surface intersection are summarized in this paper. Note that these techniques are generic and widely used in various applications but play a key role in 3D geological modeling. There are two essential procedures in 3D geological modeling: the first is the simulation of geological interfaces using geometric surfaces and the second is the building of geological objects by means of various geometric computations such as the intersection of surfaces. Discrete geometric surfaces that represent geological interfaces can be generated by creating planar meshes first and then spatially interpolating; those surfaces intersect and then form volumes that represent three-dimensional geological objects such as rock bodies. In this paper, the most commonly used algorithms of the key techniques in 3D geological modeling are summarized.
Summary on Several Key Techniques in 3D Geological Modeling
2014-01-01
Several key techniques in 3D geological modeling including planar mesh generation, spatial interpolation, and surface intersection are summarized in this paper. Note that these techniques are generic and widely used in various applications but play a key role in 3D geological modeling. There are two essential procedures in 3D geological modeling: the first is the simulation of geological interfaces using geometric surfaces and the second is the building of geological objects by means of various geometric computations such as the intersection of surfaces. Discrete geometric surfaces that represent geological interfaces can be generated by creating planar meshes first and then spatially interpolating; those surfaces intersect and then form volumes that represent three-dimensional geological objects such as rock bodies. In this paper, the most commonly used algorithms of the key techniques in 3D geological modeling are summarized. PMID:24772029
Time dependence of breakdown in a global fiber-bundle model with continuous damage
NASA Astrophysics Data System (ADS)
Moral, L.; Moreno, Y.; Gómez, J. B.; Pacheco, A. F.
2001-06-01
A time-dependent global fiber-bundle model of fracture with continuous damage is formulated in terms of a set of coupled nonlinear differential equations. A first integral of this set is analytically obtained. The time evolution of the system is studied by applying a discrete probabilistic method. Several results are discussed emphasizing their differences with the standard time-dependent model. The results obtained show that with this simple model a variety of experimental observations can be qualitatively reproduced.
Formal representation of 3D structural geological models
NASA Astrophysics Data System (ADS)
Wang, Zhangang; Qu, Honggang; Wu, Zixing; Yang, Hongjun; Du, Qunle
2016-05-01
The development and widespread application of geological modeling methods has increased demands for the integration and sharing services of three dimensional (3D) geological data. However, theoretical research in the field of geological information sciences is limited despite the widespread use of Geographic Information Systems (GIS) in geology. In particular, fundamental research on the formal representations and standardized spatial descriptions of 3D structural models is required. This is necessary for accurate understanding and further applications of geological data in 3D space. In this paper, we propose a formal representation method for 3D structural models using the theory of point set topology, which produces a mathematical definition for the major types of geological objects. The spatial relationships between geologic boundaries, structures, and units are explained in detail using the 9-intersection model. Reasonable conditions for describing the topological space of 3D structural models are also provided. The results from this study can be used as potential support for the standardized representation and spatial quality evaluation of 3D structural models, as well as for specific needs related to model-based management, query, and analysis.
On numerical model of time-dependent processes in three-dimensional porous heat-releasing objects
NASA Astrophysics Data System (ADS)
Lutsenko, Nickolay A.
2016-10-01
The gas flows in the gravity field through porous objects with heat-releasing sources are investigated when the self-regulation of the flow rate of the gas passing through the porous object takes place. Such objects can appear after various natural or man-made disasters (like the exploded unit of the Chernobyl NPP). The mathematical model and the original numerical method, based on a combination of explicit and implicit finite difference schemes, are developed for investigating the time-dependent processes in 3D porous energy-releasing objects. The advantage of the numerical model is its ability to describe unsteady processes under both natural convection and forced filtration. The gas cooling of 3D porous objects with different distribution of heat sources is studied using computational experiment.
Vehicle Surveillance with a Generic, Adaptive, 3D Vehicle Model.
Leotta, Matthew J; Mundy, Joseph L
2011-07-01
In automated surveillance, one is often interested in tracking road vehicles, measuring their shape in 3D world space, and determining vehicle classification. To address these tasks simultaneously, an effective approach is the constrained alignment of a prior model of 3D vehicle shape to images. Previous 3D vehicle models are either generic but overly simple or rigid and overly complex. Rigid models represent exactly one vehicle design, so a large collection is needed. A single generic model can deform to a wide variety of shapes, but those shapes have been far too primitive. This paper uses a generic 3D vehicle model that deforms to match a wide variety of passenger vehicles. It is adjustable in complexity between the two extremes. The model is aligned to images by predicting and matching image intensity edges. Novel algorithms are presented for fitting models to multiple still images and simultaneous tracking while estimating shape in video. Experiments compare the proposed model to simple generic models in accuracy and reliability of 3D shape recovery from images and tracking in video. Standard techniques for classification are also used to compare the models. The proposed model outperforms the existing simple models at each task.
3D Modeling from Photos Given Topological Information.
Kim, Young Min; Cho, Junghyun; Ahn, Sang Chul
2016-09-01
Reconstructing 3D models given a single-view 2D information is inherently an ill-posed problem and requires additional information such as shape prior or user input.We introduce a method to generate multiple 3D models of a particular category given corresponding photographs when the topological information is known. While there is a wide range of shapes for an object of a particular category, the basic topology usually remains constant.In consequence, the topological prior needs to be provided only once for each category and can be easily acquired by consulting an existing database of 3D models or by user input. The input of topological description is only connectivity information between parts; this is in contrast to previous approaches that have required users to interactively mark individual parts. Given the silhouette of an object and the topology, our system automatically finds a skeleton and generates a textured 3D model by jointly fitting multiple parts. The proposed method, therefore, opens the possibility of generating a large number of 3D models by consulting a massive number of photographs. We demonstrate examples of the topological prior and reconstructed 3D models using photos.
Performance Evaluation of 3d Modeling Software for Uav Photogrammetry
NASA Astrophysics Data System (ADS)
Yanagi, H.; Chikatsu, H.
2016-06-01
UAV (Unmanned Aerial Vehicle) photogrammetry, which combines UAV and freely available internet-based 3D modeling software, is widely used as a low-cost and user-friendly photogrammetry technique in the fields such as remote sensing and geosciences. In UAV photogrammetry, only the platform used in conventional aerial photogrammetry is changed. Consequently, 3D modeling software contributes significantly to its expansion. However, the algorithms of the 3D modelling software are black box algorithms. As a result, only a few studies have been able to evaluate their accuracy using 3D coordinate check points. With this motive, Smart3DCapture and Pix4Dmapper were downloaded from the Internet and commercial software PhotoScan was also employed; investigations were performed in this paper using check points and images obtained from UAV.
A TIME-DEPENDENT RADIATIVE MODEL FOR THE ATMOSPHERE OF THE ECCENTRIC EXOPLANETS
Iro, N.; Deming, L. D. E-mail: leo.d.deming@nasa.go
2010-03-20
We present a time-dependent radiative model for the atmosphere of extrasolar planets that takes into account the eccentricity of their orbit. In addition to the modulation of stellar irradiation by the varying planet-star distance, the pseudo-synchronous rotation of the planets may play a significant role. We include both of these time-dependent effects when modeling the planetary thermal structure. We investigate the thermal structure and spectral characteristics for time-dependent stellar heating for two highly eccentric planets. Finally, we discuss observational aspects for those planets suitable for Spitzer measurements and investigate the role of the rotation rate.
A time-dependent probabilistic seismic-hazard model for California
Cramer, C.H.; Petersen, M.D.; Cao, T.; Toppozada, Tousson R.; Reichle, M.
2000-01-01
For the purpose of sensitivity testing and illuminating nonconsensus components of time-dependent models, the California Department of Conservation, Division of Mines and Geology (CDMG) has assembled a time-dependent version of its statewide probabilistic seismic hazard (PSH) model for California. The model incorporates available consensus information from within the earth-science community, except for a few faults or fault segments where consensus information is not available. For these latter faults, published information has been incorporated into the model. As in the 1996 CDMG/U.S. Geological Survey (USGS) model, the time-dependent models incorporate three multisegment ruptures: a 1906, an 1857, and a southern San Andreas earthquake. Sensitivity tests are presented to show the effect on hazard and expected damage estimates of (1) intrinsic (aleatory) sigma, (2) multisegment (cascade) vs. independent segment (no cascade) ruptures, and (3) time-dependence vs. time-independence. Results indicate that (1) differences in hazard and expected damage estimates between time-dependent and independent models increase with decreasing intrinsic sigma, (2) differences in hazard and expected damage estimates between full cascading and not cascading are insensitive to intrinsic sigma, (3) differences in hazard increase with increasing return period (decreasing probability of occurrence), and (4) differences in moment-rate budgets increase with decreasing intrinsic sigma and with the degree of cascading, but are within the expected uncertainty in PSH time-dependent modeling and do not always significantly affect hazard and expected damage estimates.
Time-Dependent Dark Energy Density and Holographic DE Model with Interaction
NASA Astrophysics Data System (ADS)
Saadat, H.; Saadat, A. M.
2011-05-01
In this article we consider holographic dark energy model with interaction and space curvature. We calculate cosmic scale factor by using the time-dependent dark energy density. Then we obtain phenomenological interaction between holographic dark energy and matter.
Metric Evaluation Pipeline for 3d Modeling of Urban Scenes
NASA Astrophysics Data System (ADS)
Bosch, M.; Leichtman, A.; Chilcott, D.; Goldberg, H.; Brown, M.
2017-05-01
Publicly available benchmark data and metric evaluation approaches have been instrumental in enabling research to advance state of the art methods for remote sensing applications in urban 3D modeling. Most publicly available benchmark datasets have consisted of high resolution airborne imagery and lidar suitable for 3D modeling on a relatively modest scale. To enable research in larger scale 3D mapping, we have recently released a public benchmark dataset with multi-view commercial satellite imagery and metrics to compare 3D point clouds with lidar ground truth. We now define a more complete metric evaluation pipeline developed as publicly available open source software to assess semantically labeled 3D models of complex urban scenes derived from multi-view commercial satellite imagery. Evaluation metrics in our pipeline include horizontal and vertical accuracy and completeness, volumetric completeness and correctness, perceptual quality, and model simplicity. Sources of ground truth include airborne lidar and overhead imagery, and we demonstrate a semi-automated process for producing accurate ground truth shape files to characterize building footprints. We validate our current metric evaluation pipeline using 3D models produced using open source multi-view stereo methods. Data and software is made publicly available to enable further research and planned benchmarking activities.
Automatic Texture Mapping of Architectural and Archaeological 3d Models
NASA Astrophysics Data System (ADS)
Kersten, T. P.; Stallmann, D.
2012-07-01
Today, detailed, complete and exact 3D models with photo-realistic textures are increasingly demanded for numerous applications in architecture and archaeology. Manual texture mapping of 3D models by digital photographs with software packages, such as Maxon Cinema 4D, Autodesk 3Ds Max or Maya, still requires a complex and time-consuming workflow. So, procedures for automatic texture mapping of 3D models are in demand. In this paper two automatic procedures are presented. The first procedure generates 3D surface models with textures by web services, while the second procedure textures already existing 3D models with the software tmapper. The program tmapper is based on the Multi Layer 3D image (ML3DImage) algorithm and developed in the programming language C++. The studies showing that the visibility analysis using the ML3DImage algorithm is not sufficient to obtain acceptable results of automatic texture mapping. To overcome the visibility problem the Point Cloud Painter algorithm in combination with the Z-buffer-procedure will be applied in the future.
Quasi-3D Algorithm in Multi-scale Modeling Framework
NASA Astrophysics Data System (ADS)
Jung, J.; Arakawa, A.
2008-12-01
As discussed in the companion paper by Arakawa and Jung, the Quasi-3D (Q3D) Multi-scale Modeling Framework (MMF) is a 4D estimation/prediction framework that combines a GCM with a 3D anelastic vector vorticity equation model (VVM) applied to a Q3D network of horizontal grid points. This paper presents an outline of the recently revised Q3D algorithm and a highlight of the results obtained by application of the algorithm to an idealized model setting. The Q3D network of grid points consists of two sets of grid-point arrays perpendicular to each other. For a scalar variable, for example, each set consists of three parallel rows of grid points. Principal and supplementary predictions are made on the central and the two adjacent rows, respectively. The supplementary prediction is to allow the principal prediction be three-dimensional at least to the second-order accuracy. To accommodate a higher-order accuracy and to make the supplementary predictions formally three-dimensional, a few rows of ghost points are added at each side of the array. Values at these ghost points are diagnostically determined by a combination of statistical estimation and extrapolation. The basic structure of the estimation algorithm is determined in view of the global stability of Q3D advection. The algorithm is calibrated using the statistics of past data at and near the intersections of the two sets of grid- point arrays. Since the CRM in the Q3D MMF extends beyond individual GCM boxes, the CRM can be a GCM by itself. However, it is better to couple the CRM with the GCM because (1) the CRM is a Q3D CRM based on a highly anisotropic network of grid points and (2) coupling with a GCM makes it more straightforward to inherit our experience with the conventional GCMs. In the coupled system we have selected, prediction of thermdynamic variables is almost entirely done by the Q3D CRM with no direct forcing by the GCM. The coupling of the dynamics between the two components is through mutual
Combined registration of 3D tibia and femur implant models in 3D magnetic resonance images
NASA Astrophysics Data System (ADS)
Englmeier, Karl-Hans; Siebert, Markus; von Eisenhart-Rothe, Ruediger; Graichen, Heiko
2008-03-01
The most frequent reasons for revision of total knee arthroplasty are loosening and abnormal axial alignment leading to an unphysiological kinematic of the knee implant. To get an idea about the postoperative kinematic of the implant, it is essential to determine the position and orientation of the tibial and femoral prosthesis. Therefore we developed a registration method for fitting 3D CAD-models of knee joint prostheses into an 3D MR image. This rigid registration is the basis for a quantitative analysis of the kinematics of knee implants. Firstly the surface data of the prostheses models are converted into a voxel representation; a recursive algorithm determines all boundary voxels of the original triangular surface data. Secondly an initial preconfiguration of the implants by the user is still necessary for the following step: The user has to perform a rough preconfiguration of both remaining prostheses models, so that the fine matching process gets a reasonable starting point. After that an automated gradient-based fine matching process determines the best absolute position and orientation: This iterative process changes all 6 parameters (3 rotational- and 3 translational parameters) of a model by a minimal amount until a maximum value of the matching function is reached. To examine the spread of the final solutions of the registration, the interobserver variability was measured in a group of testers. This variability, calculated by the relative standard deviation, improved from about 50% (pure manual registration) to 0.5% (rough manual preconfiguration and subsequent fine registration with the automatic fine matching process).
Brown, D.B.; Jenkins, W.C. ); Johnston, A.H. )
1989-12-01
A simple model for interpreting and extrapolating time dependent effects is tested by fitting to published and previously unpublished experimental data. The goal is to evaluate the applicability of such a model to hardness assurance testing in cases where defect growth and annealing processes (time dependent effects) are significant. Data is presented indicating hole annealing times varying by more than six orders of magnitude. The implications of the large variation in hole annealing times for hardness assurance testing are explored.
Gis-Based Smart Cartography Using 3d Modeling
NASA Astrophysics Data System (ADS)
Malinverni, E. S.; Tassetti, A. N.
2013-08-01
3D City Models have evolved to be important tools for urban decision processes and information systems, especially in planning, simulation, analysis, documentation and heritage management. On the other hand existing and in use numerical cartography is often not suitable to be used in GIS because not geometrically and topologically correctly structured. The research aim is to 3D structure and organize a numeric cartography for GIS and turn it into CityGML standardized features. The work is framed around a first phase of methodological analysis aimed to underline which existing standard (like ISO and OGC rules) can be used to improve the quality requirement of a cartographic structure. Subsequently, from this technical specifics, it has been investigated the translation in formal contents, using an owner interchange software (SketchUp), to support some guide lines implementations to generate a GIS3D structured in GML3. It has been therefore predisposed a test three-dimensional numerical cartography (scale 1:500, generated from range data captured by 3D laser scanner), tested on its quality according to the previous standard and edited when and where necessary. Cad files and shapefiles are converted into a final 3D model (Google SketchUp model) and then exported into a 3D city model (CityGML LoD1/LoD2). The GIS3D structure has been managed in a GIS environment to run further spatial analysis and energy performance estimate, not achievable in a 2D environment. In particular geometrical building parameters (footprint, volume etc.) are computed and building envelop thermal characteristics are derived from. Lastly, a simulation is carried out to deal with asbestos and home renovating charges and show how the built 3D city model can support municipal managers with risk diagnosis of the present situation and development of strategies for a sustainable redevelop.
NASA Astrophysics Data System (ADS)
Junk, S.
2016-08-01
Today the methods of numerical simulation of sheet metal forming offer a great diversity of possibilities for optimization in product development and in process design. However, the results from simulation are only available as virtual models. Because there are any forming tools available during the early stages of product development, physical models that could serve to represent the virtual results are therefore lacking. Physical 3D-models can be created using 3D-printing and serve as an illustration and present a better understanding of the simulation results. In this way, the results from the simulation can be made more “comprehensible” within a development team. This paper presents the possibilities of 3D-colour printing with particular consideration of the requirements regarding the implementation of sheet metal forming simulation. Using concrete examples of sheet metal forming, the manufacturing of 3D colour models will be expounded upon on the basis of simulation results.
Dynamics of a Hogg-Huberman Model with Time Dependent Reevaluation Rates
NASA Astrophysics Data System (ADS)
Tanaka, Toshijiro; Kurihara, Tetsuya; Inoue, Masayoshi
2006-05-01
The dynamical behavior of the Hogg-Huberman model with time-dependent reevaluation rates is studied. The time dependence of the reevaluation rate that agents using one of resources decide to consider their resource choice is obtained in terms of states of the system. It is seen that the change of fraction of agents using one resource is suppressed to be smaller than that in the case of a fixed reevaluation rate and the chaos control in the system associated with time-dependent reevaluation rates can be performed by the system itself.
3D WHOLE-PROMINENCE FINE STRUCTURE MODELING
Gunár, Stanislav; Mackay, Duncan H.
2015-04-20
We present the first 3D whole-prominence fine structure model. The model combines a 3D magnetic field configuration of an entire prominence obtained from nonlinear force-free field simulations, with a detailed description of the prominence plasma. The plasma is located in magnetic dips in hydrostatic equilibrium and is distributed along multiple fine structures within the 3D magnetic model. Through the use of a novel radiative transfer visualization technique for the Hα line such plasma-loaded magnetic field model produces synthetic images of the modeled prominence comparable with high-resolution observations. This allows us for the first time to use a single technique to consistently study, in both emission on the limb and absorption against the solar disk, the fine structures of prominences/filaments produced by a magnetic field model.
3D Bioprinting of Tissue/Organ Models.
Pati, Falguni; Gantelius, Jesper; Svahn, Helene Andersson
2016-04-04
In vitro tissue/organ models are useful platforms that can facilitate systematic, repetitive, and quantitative investigations of drugs/chemicals. The primary objective when developing tissue/organ models is to reproduce physiologically relevant functions that typically require complex culture systems. Bioprinting offers exciting prospects for constructing 3D tissue/organ models, as it enables the reproducible, automated production of complex living tissues. Bioprinted tissues/organs may prove useful for screening novel compounds or predicting toxicity, as the spatial and chemical complexity inherent to native tissues/organs can be recreated. In this Review, we highlight the importance of developing 3D in vitro tissue/organ models by 3D bioprinting techniques, characterization of these models for evaluating their resemblance to native tissue, and their application in the prioritization of lead candidates, toxicity testing, and as disease/tumor models.
3D web visualization of huge CityGML models
NASA Astrophysics Data System (ADS)
Prandi, F.; Devigili, F.; Soave, M.; Di Staso, U.; De Amicis, R.
2015-08-01
Nowadays, rapid technological development into acquiring geo-spatial information; joined to the capabilities to process these data in a relative short period of time, allows the generation of detailed 3D textured city models that will become an essential part of the modern city information infrastructure (Spatial Data Infrastructure) and, can be used to integrate various data from different sources for public accessible visualisation and many other applications. One of the main bottlenecks, which at the moment limit the use of these datasets to few experts, is a lack on efficient visualization systems through the web and interoperable frameworks that allow standardising the access to the city models. The work presented in this paper tries to satisfy these two requirements developing a 3D web-based visualization system based on OGC standards and effective visualization concepts. The architectural framework, based on Services Oriented Architecture (SOA) concepts, provides the 3D city data to a web client designed to support the view process in a very effective way. The first part of the work is to design a framework compliant to the 3D Portrayal Service drafted by the of the Open Geospatial Consortium (OGC) 3D standardization working group. The latter is related to the development of an effective web client able to render in an efficient way the 3D city models.
3D microstructure modeling of compressed fiber-based materials
NASA Astrophysics Data System (ADS)
Gaiselmann, Gerd; Tötzke, Christian; Manke, Ingo; Lehnert, Werner; Schmidt, Volker
2014-07-01
A novel parametrized model that describes the 3D microstructure of compressed fiber-based materials is introduced. It allows to virtually generate the microstructure of realistically compressed gas-diffusion layers (GDL). Given the input of a 3D microstructure of some fiber-based material, the model compresses the system of fibers in a uniaxial direction for arbitrary compression rates. The basic idea is to translate the fibers in the direction of compression according to a vector field which depends on the rate of compression and on the locations of fibers within the material. In order to apply the model to experimental 3D image data of fiber-based materials given for several compression states, an optimal vector field is estimated by simulated annealing. The model is applied to 3D image data of non-woven GDL in PEMFC gained by synchrotron tomography for different compression rates. The compression model is validated by comparing structural characteristics computed for experimentally compressed and virtually compressed microstructures, where two kinds of compression - using a flat stamp and a stamp with a flow-field profile - are applied. For both stamps types, a good agreement is found. Furthermore, the compression model is combined with a stochastic 3D microstructure model for uncompressed fiber-based materials. This allows to efficiently generate compressed fiber-based microstructures in arbitrary volumes.
Consistency between 2D-3D Sediment Transport models
NASA Astrophysics Data System (ADS)
Villaret, Catherine; Jodeau, Magali
2017-04-01
Sediment transport models have been developed and applied by the engineering community to estimate transport rates and morphodynamic bed evolutions in river flows, coastal and estuarine conditions. Environmental modelling systems like the open-source Telemac modelling system include a hierarchy of models from 1D (Mascaret), 2D (Telemac-2D/Sisyphe) and 3D (Telemac-3D/Sedi-3D) and include a wide range of processes to represent sediment flow interactions under more and more complex situations (cohesive, non-cohesive and mixed sediment). Despite some tremendous progresses in the numerical techniques and computing resources, the quality/accuracy of model results mainly depend on the numerous choices and skills of the modeler. In complex situations involving stratification effects, complex geometry, recirculating flows… 2D model assumptions are no longer valid. A full 3D turbulent flow model is then required in order to capture the vertical mixing processes and to represent accurately the coupled flow/sediment distribution. However a number of theoretical and numerical difficulties arise when dealing with sediment transport modelling in 3D which will be high-lighted : (1) Dependency of model results to the vertical grid refinement and choice of boundary conditions and numerical scheme (2) The choice of turbulence model determines also the sediment vertical distribution which is governed by a balance between the downward settling term and upward turbulent diffusion. (3) The use of different numerical schemes for both hydrodynamics (mean and turbulent flow) and sediment transport modelling can lead to some inconsistency including a mismatch in the definition of numerical cells and definition of boundary conditions. We discuss here those present issues and present some detailed comparison between 2D and 3D simulations on a set of validation test cases which are available in the Telemac 7.2 release using both cohesive and non-cohesive sediments.
Perception-based shape retrieval for 3D building models
NASA Astrophysics Data System (ADS)
Zhang, Man; Zhang, Liqiang; Takis Mathiopoulos, P.; Ding, Yusi; Wang, Hao
2013-01-01
With the help of 3D search engines, a large number of 3D building models can be retrieved freely online. A serious disadvantage of most rotation-insensitive shape descriptors is their inability to distinguish between two 3D building models which are different at their main axes, but appear similar when one of them is rotated. To resolve this problem, we present a novel upright-based normalization method which not only correctly rotates such building models, but also greatly simplifies and accelerates the abstraction and the matching of building models' shape descriptors. Moreover, the abundance of architectural styles significantly hinders the effective shape retrieval of building models. Our research has shown that buildings with different designs are not well distinguished by the widely recognized shape descriptors for general 3D models. Motivated by this observation and to further improve the shape retrieval quality, a new building matching method is introduced and analyzed based on concepts found in the field of perception theory and the well-known Light Field descriptor. The resulting normalized building models are first classified using the qualitative shape descriptors of Shell and Unevenness which outline integral geometrical and topological information. These models are then put in on orderly fashion with the help of an improved quantitative shape descriptor which we will term as Horizontal Light Field Descriptor, since it assembles detailed shape characteristics. To accurately evaluate the proposed methodology, an enlarged building shape database which extends previous well-known shape benchmarks was implemented as well as a model retrieval system supporting inputs from 2D sketches and 3D models. Various experimental performance evaluation results have shown that, as compared to previous methods, retrievals employing the proposed matching methodology are faster and more consistent with human recognition of spatial objects. In addition these performance
Shape: A 3D Modeling Tool for Astrophysics.
Steffen, Wolfgang; Koning, Nicholas; Wenger, Stephan; Morisset, Christophe; Magnor, Marcus
2011-04-01
We present a flexible interactive 3D morpho-kinematical modeling application for astrophysics. Compared to other systems, our application reduces the restrictions on the physical assumptions, data type, and amount that is required for a reconstruction of an object's morphology. It is one of the first publicly available tools to apply interactive graphics to astrophysical modeling. The tool allows astrophysicists to provide a priori knowledge about the object by interactively defining 3D structural elements. By direct comparison of model prediction with observational data, model parameters can then be automatically optimized to fit the observation. The tool has already been successfully used in a number of astrophysical research projects.
Partonomies for interactive explorable 3D-models of anatomy.
Schubert, R.; HÃ¶hne, K. H.
1998-01-01
We introduce a concept to model subtle part-whole-semantics for the use with interactive 3d-models of human anatomy. Similar to experiences with modeling partonomies for physical artifacts like machines or buildings we found one unique part-whole-relation to be insufficient to represent anatomical reality. This claim will be illustrated with anatomical examples. According to the requirements these examples demand, a semantic classification of part-whole-relations is introduced. Initial results in modeling anatomical partonomies for a 3d-visualization environment proved this approach to be an promising way to represent anatomy and to enable powerful complex inferences. Images Figure 2 Figure 4 PMID:9929256
Eck, Simon; Wörz, Stefan; Müller-Ott, Katharina; Hahn, Matthias; Biesdorf, Andreas; Schotta, Gunnar; Rippe, Karsten; Rohr, Karl
2016-08-01
The genome is partitioned into regions of euchromatin and heterochromatin. The organization of heterochromatin is important for the regulation of cellular processes such as chromosome segregation and gene silencing, and their misregulation is linked to cancer and other diseases. We present a model-based approach for automatic 3D segmentation and 3D shape analysis of heterochromatin foci from 3D confocal light microscopy images. Our approach employs a novel 3D intensity model based on spherical harmonics, which analytically describes the shape and intensities of the foci. The model parameters are determined by fitting the model to the image intensities using least-squares minimization. To characterize the 3D shape of the foci, we exploit the computed spherical harmonics coefficients and determine a shape descriptor. We applied our approach to 3D synthetic image data as well as real 3D static and real 3D time-lapse microscopy images, and compared the performance with that of previous approaches. It turned out that our approach yields accurate 3D segmentation results and performs better than previous approaches. We also show that our approach can be used for quantifying 3D shape differences of heterochromatin foci.
Aortic valve and ascending aortic root modeling from 3D and 3D+t CT
NASA Astrophysics Data System (ADS)
Grbic, Saša; Ionasec, Razvan I.; Zäuner, Dominik; Zheng, Yefeng; Georgescu, Bogdan; Comaniciu, Dorin
2010-02-01
Aortic valve disorders are the most frequent form of valvular heart disorders (VHD) affecting nearly 3% of the global population. A large fraction among them are aortic root diseases, such as aortic root aneurysm, often requiring surgical procedures (valve-sparing) as a treatment. Visual non-invasive assessment techniques could assist during pre-selection of adequate patients, planning procedures and afterward evaluation of the same. However state of the art approaches try to model a rather short part of the aortic root, insufficient to assist the physician during intervention planning. In this paper we propose a novel approach for morphological and functional quantification of both the aortic valve and the ascending aortic root. A novel physiological shape model is introduced, consisting of the aortic valve root, leaflets and the ascending aortic root. The model parameters are hierarchically estimated using robust and fast learning-based methods. Experiments performed on 63 CT sequences (630 Volumes) and 20 single phase CT volumes demonstrated an accuracy of 1.45mm and an performance of 30 seconds (3D+t) for this approach. To the best of our knowledge this is the first time a complete model of the aortic valve (including leaflets) and the ascending aortic root, estimated from CT, has been proposed.
3D Printing of Biomolecular Models for Research and Pedagogy
Da Veiga Beltrame, Eduardo; Tyrwhitt-Drake, James; Roy, Ian; Shalaby, Raed; Suckale, Jakob; Pomeranz Krummel, Daniel
2017-01-01
The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D structures are most often perceived using the two-dimensional and exclusively visual medium of the computer screen. Converting digital 3D molecular data into real objects enables information to be perceived through an expanded range of human senses, including direct stereoscopic vision, touch, and interaction. Such tangible models facilitate new insights, enable hypothesis testing, and serve as psychological or sensory anchors for conceptual information about the functions of biomolecules. Recent advances in consumer 3D printing technology enable, for the first time, the cost-effective fabrication of high-quality and scientifically accurate models of biomolecules in a variety of molecular representations. However, the optimization of the virtual model and its printing parameters is difficult and time consuming without detailed guidance. Here, we provide a guide on the digital design and physical fabrication of biomolecule models for research and pedagogy using open source or low-cost software and low-cost 3D printers that use fused filament fabrication technology. PMID:28362403
3D Printing of Biomolecular Models for Research and Pedagogy.
Da Veiga Beltrame, Eduardo; Tyrwhitt-Drake, James; Roy, Ian; Shalaby, Raed; Suckale, Jakob; Pomeranz Krummel, Daniel
2017-03-13
The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D structures are most often perceived using the two-dimensional and exclusively visual medium of the computer screen. Converting digital 3D molecular data into real objects enables information to be perceived through an expanded range of human senses, including direct stereoscopic vision, touch, and interaction. Such tangible models facilitate new insights, enable hypothesis testing, and serve as psychological or sensory anchors for conceptual information about the functions of biomolecules. Recent advances in consumer 3D printing technology enable, for the first time, the cost-effective fabrication of high-quality and scientifically accurate models of biomolecules in a variety of molecular representations. However, the optimization of the virtual model and its printing parameters is difficult and time consuming without detailed guidance. Here, we provide a guide on the digital design and physical fabrication of biomolecule models for research and pedagogy using open source or low-cost software and low-cost 3D printers that use fused filament fabrication technology.
NASA Astrophysics Data System (ADS)
Song, Chi; Zhang, Xuejun; Zhang, Xin; Hu, Haifei; Zeng, Xuefeng
2017-06-01
A rigid conformal (RC) lap can smooth mid-spatial-frequency (MSF) errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing efficiency performance is poorer than expected, and existing smoothing models cannot explicitly specify the methods to improve this efficiency. We presented an explicit time-dependent smoothing evaluation model that contained specific smoothing parameters directly derived from the parametric smoothing model and the Preston equation. Based on the time-dependent model, we proposed a strategy to improve the RC-lap smoothing efficiency, which incorporated the theoretical model, tool optimization, and efficiency limit determination. Two sets of smoothing experiments were performed to demonstrate the smoothing efficiency achieved using the time-dependent smoothing model. A high, theory-like tool influence function and a limiting tool speed of 300 RPM were o
NASA Astrophysics Data System (ADS)
Song, Chi; Zhang, Xuejun; Zhang, Xin; Hu, Haifei; Zeng, Xuefeng
2017-01-01
A rigid conformal (RC) lap can smooth mid-spatial-frequency (MSF) errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing efficiency performance is poorer than expected, and existing smoothing models cannot explicitly specify the methods to improve this efficiency. We presented an explicit time-dependent smoothing evaluation model that contained specific smoothing parameters directly derived from the parametric smoothing model and the Preston equation. Based on the time-dependent model, we proposed a strategy to improve the RC-lap smoothing efficiency, which incorporated the theoretical model, tool optimization, and efficiency limit determination. Two sets of smoothing experiments were performed to demonstrate the smoothing efficiency achieved using the time-dependent smoothing model. A high, theory-like tool influence function and a limiting tool speed of 300 RPM were o
MR image denoising method for brain surface 3D modeling
NASA Astrophysics Data System (ADS)
Zhao, De-xin; Liu, Peng-jie; Zhang, De-gan
2014-11-01
Three-dimensional (3D) modeling of medical images is a critical part of surgical simulation. In this paper, we focus on the magnetic resonance (MR) images denoising for brain modeling reconstruction, and exploit a practical solution. We attempt to remove the noise existing in the MR imaging signal and preserve the image characteristics. A wavelet-based adaptive curve shrinkage function is presented in spherical coordinates system. The comparative experiments show that the denoising method can preserve better image details and enhance the coefficients of contours. Using these denoised images, the brain 3D visualization is given through surface triangle mesh model, which demonstrates the effectiveness of the proposed method.
STELLOPT Modeling of the 3D Diagnostic Response in ITER
Lazerson, Samuel A
2013-05-07
The ITER three dimensional diagnostic response to an n=3 resonant magnetic perturbation is modeled using the STELLOPT code. The in-vessel coils apply a resonant magnetic perturbation (RMP) fi eld which generates a 4 cm edge displacement from axisymmetry as modeled by the VMEC 3D equilibrium code. Forward modeling of flux loop and magnetic probe response with the DIAGNO code indicates up to 20 % changes in measured plasma signals. Simulated LIDAR measurements of electron temperature indicate 2 cm shifts on the low field side of the plasma. This suggests that the ITER diagnostic will be able to diagnose the 3D structure of the equilibria.
NASA Astrophysics Data System (ADS)
Uznir, U.; Anton, F.; Suhaibah, A.; Rahman, A. A.; Mioc, D.
2013-09-01
The advantages of three dimensional (3D) city models can be seen in various applications including photogrammetry, urban and regional planning, computer games, etc.. They expand the visualization and analysis capabilities of Geographic Information Systems on cities, and they can be developed using web standards. However, these 3D city models consume much more storage compared to two dimensional (2D) spatial data. They involve extra geometrical and topological information together with semantic data. Without a proper spatial data clustering method and its corresponding spatial data access method, retrieving portions of and especially searching these 3D city models, will not be done optimally. Even though current developments are based on an open data model allotted by the Open Geospatial Consortium (OGC) called CityGML, its XML-based structure makes it challenging to cluster the 3D urban objects. In this research, we propose an opponent data constellation technique of space-filling curves (3D Hilbert curves) for 3D city model data representation. Unlike previous methods, that try to project 3D or n-dimensional data down to 2D or 3D using Principal Component Analysis (PCA) or Hilbert mappings, in this research, we extend the Hilbert space-filling curve to one higher dimension for 3D city model data implementations. The query performance was tested using a CityGML dataset of 1,000 building blocks and the results are presented in this paper. The advantages of implementing space-filling curves in 3D city modeling will improve data retrieval time by means of optimized 3D adjacency, nearest neighbor information and 3D indexing. The Hilbert mapping, which maps a subinterval of the [0, 1] interval to the corresponding portion of the d-dimensional Hilbert's curve, preserves the Lebesgue measure and is Lipschitz continuous. Depending on the applications, several alternatives are possible in order to cluster spatial data together in the third dimension compared to its
Potential of 3D City Models to assess flood vulnerability
NASA Astrophysics Data System (ADS)
Schröter, Kai; Bochow, Mathias; Schüttig, Martin; Nagel, Claus; Ross, Lutz; Kreibich, Heidi
2016-04-01
Vulnerability, as the product of exposure and susceptibility, is a key factor of the flood risk equation. Furthermore, the estimation of flood loss is very sensitive to the choice of the vulnerability model. Still, in contrast to elaborate hazard simulations, vulnerability is often considered in a simplified manner concerning the spatial resolution and geo-location of exposed objects as well as the susceptibility of these objects at risk. Usually, area specific potential flood loss is quantified on the level of aggregated land-use classes, and both hazard intensity and resistance characteristics of affected objects are represented in highly simplified terms. We investigate the potential of 3D City Models and spatial features derived from remote sensing data to improve the differentiation of vulnerability in flood risk assessment. 3D City Models are based on CityGML, an application scheme of the Geography Markup Language (GML), which represents the 3D geometry, 3D topology, semantics and appearance of objects on different levels of detail. As such, 3D City Models offer detailed spatial information which is useful to describe the exposure and to characterize the susceptibility of residential buildings at risk. This information is further consolidated with spatial features of the building stock derived from remote sensing data. Using this database a spatially detailed flood vulnerability model is developed by means of data-mining. Empirical flood damage data are used to derive and to validate flood susceptibility models for individual objects. We present first results from a prototype application in the city of Dresden, Germany. The vulnerability modeling based on 3D City Models and remote sensing data is compared i) to the generally accepted good engineering practice based on area specific loss potential and ii) to a highly detailed representation of flood vulnerability based on a building typology using urban structure types. Comparisons are drawn in terms of
3D head model classification using optimized EGI
NASA Astrophysics Data System (ADS)
Tong, Xin; Wong, Hau-san; Ma, Bo
2006-02-01
With the general availability of 3D digitizers and scanners, 3D graphical models have been used widely in a variety of applications. This has led to the development of search engines for 3D models. Especially, 3D head model classification and retrieval have received more and more attention in view of their many potential applications in criminal identifications, computer animation, movie industry and medical industry. This paper addresses the 3D head model classification problem using 2D subspace analysis methods such as 2D principal component analysis (2D PCA[3]) and 2D fisher discriminant analysis (2DLDA[5]). It takes advantage of the fact that the histogram is a 2D image, and we can extract the most useful information from these 2D images to get a good result accordingingly. As a result, there are two main advantages: First, we can perform less calculation to obtain the same rate of classification; second, we can reduce the dimensionality more than PCA to obtain a higher efficiency.
3D MHD Models of Active Region Loops
NASA Technical Reports Server (NTRS)
Ofman, Leon
2004-01-01
Present imaging and spectroscopic observations of active region loops allow to determine many physical parameters of the coronal loops, such as the density, temperature, velocity of flows in loops, and the magnetic field. However, due to projection effects many of these parameters remain ambiguous. Three dimensional imaging in EUV by the STEREO spacecraft will help to resolve the projection ambiguities, and the observations could be used to setup 3D MHD models of active region loops to study the dynamics and stability of active regions. Here the results of 3D MHD models of active region loops are presented, and the progress towards more realistic 3D MHD models of active regions. In particular the effects of impulsive events on the excitation of active region loop oscillations, and the generation, propagations and reflection of EIT waves are shown. It is shown how 3D MHD models together with 3D EUV observations can be used as a diagnostic tool for active region loop physical parameters, and to advance the science of the sources of solar coronal activity.
Thermal 3D modeling system based on 3-view geometry
NASA Astrophysics Data System (ADS)
Yu, Sunjin; Kim, Joongrock; Lee, Sangyoun
2012-11-01
In this paper, we propose a novel thermal three-dimensional (3D) modeling system that includes 3D shape, visual, and thermal infrared information and solves a registration problem among these three types of information. The proposed system consists of a projector, a visual camera and, a thermal camera (PVT). To generate 3D shape information, we use a structured light technique, which consists of a visual camera and a projector. A thermal camera is added to the structured light system in order to provide thermal information. To solve the correspondence problem between the three sensors, we use three-view geometry. Finally, we obtain registered PVT data, which includes visual, thermal, and 3D shape information. Among various potential applications such as industrial measurements, biological experiments, military usage, and so on, we have adapted the proposed method to biometrics, particularly for face recognition. With the proposed method, we obtain multi-modal 3D face data that includes not only textural information but also data regarding head pose, 3D shape, and thermal information. Experimental results show that the performance of the proposed face recognition system is not limited by head pose variation which is a serious problem in face recognition.
Integration of 3D photogrammetric outcrop models in the reservoir modelling workflow
NASA Astrophysics Data System (ADS)
Deschamps, Remy; Joseph, Philippe; Lerat, Olivier; Schmitz, Julien; Doligez, Brigitte; Jardin, Anne
2014-05-01
3D technologies are now widely used in geosciences to reconstruct outcrops in 3D. The technology used for the 3D reconstruction is usually based on Lidar, which provides very precise models. Such datasets offer the possibility to build well-constrained outcrop analogue models for reservoir study purposes. The photogrammetry is an alternate methodology which principles are based in determining the geometric properties of an object from photographic pictures taken from different angles. Outcrop data acquisition is easy, and this methodology allows constructing 3D outcrop models with many advantages such as: - light and fast acquisition, - moderate processing time (depending on the size of the area of interest), - integration of field data and 3D outcrops into the reservoir modelling tools. Whatever the method, the advantages of digital outcrop model are numerous as already highlighted by Hodgetts (2013), McCaffrey et al. (2005) and Pringle et al. (2006): collection of data from otherwise inaccessible areas, access to different angles of view, increase of the possible measurements, attributes analysis, fast rate of data collection, and of course training and communication. This paper proposes a workflow where 3D geocellular models are built by integrating all sources of information from outcrops (surface picking, sedimentological sections, structural and sedimentary dips…). The 3D geomodels that are reconstructed can be used at the reservoir scale, in order to compare the outcrop information with subsurface models: the detailed facies models of the outcrops are transferred into petrophysical and acoustic models, which are used to test different scenarios of seismic and fluid flow modelling. The detailed 3D models are also used to test new techniques of static reservoir modelling, based either on geostatistical approaches or on deterministic (process-based) simulation techniques. A modelling workflow has been designed to model reservoir geometries and properties from
NASA Astrophysics Data System (ADS)
Harvey, R. W.; Petrov, Yu.; Jaeger, E. F.; Berry, L. A.; Bonoli, P. T.; Bader, A.
2015-12-01
A time-dependent simulation of C-Mod pulsed TCRF power is made obtaining minority hydrogen ion distributions with the CQL3D-Hybrid-FOW finite-orbit-width Fokker-Planck code. Cyclotron-resonant TCRF fields are calculated with the AORSA full wave code. The RF diffusion coefficients used in CQL3D are obtained with the DC Lorentz gyro-orbit code for perturbed particle trajectories in the combined equilibrium and TCRF electromagnetic fields. Prior results with a zero-banana-width simulation using the CQL3D/AORSA/DC time-cycles showed a pronounced enhancement of the H distribution in the perpendicular velocity direction compared to results obtained from Stix's quasilinear theory, and this substantially increased the rampup rate of the observed vertically-viewed neutral particle analyzer (NPA) flux, in general agreement with experiment. However, ramp down of the NPA flux after the pulse, remained long compared to the experiment. The present study compares the new FOW results, including relevant gyro-radius effects, to determine the importance of these new effects on the the NPA time-dependence.
Digital holographic microscopy for imaging growth and treatment response in 3D tumor models
NASA Astrophysics Data System (ADS)
Li, Yuyu; Petrovic, Ljubica; Celli, Jonathan P.; Yelleswarapu, Chandra S.
2014-03-01
While three-dimensional tumor models have emerged as valuable tools in cancer research, the ability to longitudinally visualize the 3D tumor architecture restored by these systems is limited with microscopy techniques that provide only qualitative insight into sample depth, or which require terminal fixation for depth-resolved 3D imaging. Here we report the use of digital holographic microscopy (DHM) as a viable microscopy approach for quantitative, non-destructive longitudinal imaging of in vitro 3D tumor models. Following established methods we prepared 3D cultures of pancreatic cancer cells in overlay geometry on extracellular matrix beds and obtained digital holograms at multiple timepoints throughout the duration of growth. The holograms were digitally processed and the unwrapped phase images were obtained to quantify nodule thickness over time under normal growth, and in cultures subject to chemotherapy treatment. In this manner total nodule volumes are rapidly estimated and demonstrated here to show contrasting time dependent changes during growth and in response to treatment. This work suggests the utility of DHM to quantify changes in 3D structure over time and suggests the further development of this approach for time-lapse monitoring of 3D morphological changes during growth and in response to treatment that would otherwise be impractical to visualize.
3D model of amphioxus steroid receptor complexed with estradiol
Baker, Michael E.; Chang, David J.
2009-08-28
The origins of signaling by vertebrate steroids are not fully understood. An important advance was the report that an estrogen-binding steroid receptor [SR] is present in amphioxus, a basal chordate with a similar body plan as vertebrates. To investigate the evolution of estrogen-binding to steroid receptors, we constructed a 3D model of amphioxus SR complexed with estradiol. This 3D model indicates that although the SR is activated by estradiol, some interactions between estradiol and human ER{alpha} are not conserved in the SR, which can explain the low affinity of estradiol for the SR. These differences between the SR and ER{alpha} in the steroid-binding domain are sufficient to suggest that another steroid is the physiological regulator of the SR. The 3D model predicts that mutation of Glu-346 to Gln will increase the affinity of testosterone for amphioxus SR and elucidate the evolution of steroid-binding to nuclear receptors.
Computational model of stereoscopic 3D visual saliency.
Wang, Junle; Da Silva, Matthieu Perreira; Le Callet, Patrick; Ricordel, Vincent
2013-06-01
Many computational models of visual attention performing well in predicting salient areas of 2D images have been proposed in the literature. The emerging applications of stereoscopic 3D display bring an additional depth of information affecting the human viewing behavior, and require extensions of the efforts made in 2D visual modeling. In this paper, we propose a new computational model of visual attention for stereoscopic 3D still images. Apart from detecting salient areas based on 2D visual features, the proposed model takes depth as an additional visual dimension. The measure of depth saliency is derived from the eye movement data obtained from an eye-tracking experiment using synthetic stimuli. Two different ways of integrating depth information in the modeling of 3D visual attention are then proposed and examined. For the performance evaluation of 3D visual attention models, we have created an eye-tracking database, which contains stereoscopic images of natural content and is publicly available, along with this paper. The proposed model gives a good performance, compared to that of state-of-the-art 2D models on 2D images. The results also suggest that a better performance is obtained when depth information is taken into account through the creation of a depth saliency map, rather than when it is integrated by a weighting method.
Generating 3D building models from architectural drawings: a survey.
Yin, Xuetao; Wonka, Peter; Razdan, Anshuman
2009-01-01
Automatically generating 3D building models from 2D architectural drawings has many useful applications in the architecture engineering and construction community. This survey of model generation from paper and CAD-based architectural drawings covers the common pipeline and compares various algorithms for each step of the process.
3D surface digitizing and modeling development at ITRI
NASA Astrophysics Data System (ADS)
Hsueh, Wen-Jean
2000-06-01
This paper gives an overview of the research and development activities in 3D surface digitizing and modeling conducted at the Industrial Technology Research Institute (ITRI) of Taiwan in the past decade. As a major technology and consulting service provider of the area, ITRI has developed 3D laser scanning digitizers ranging from low-cost compacts, industrial CAD/CAM digitizing, to large human body scanner, with in-house 3D surface modeling software to provide total solution in reverse engineering that requires processing capabilities of large number of 3D data. Based on both hardware and software technologies in scanning, merging, registration, surface fitting, reconstruction, and compression, ITRI is now exploring innovative methodologies that provide higher performances, including hardware-based correlation algorithms with advanced camera designs, animation surface model reconstruction, and optical tracking for motion capture. It is expected that the need for easy and fast high-quality 3D information in the near future will grow exponentially, at the same amazing rate as the internet and the human desire for realistic and natural images.
Air Pollution Modeling Using A 3-d Hemispheric Nested Model
NASA Astrophysics Data System (ADS)
Frohn, L. M.; Christensen, J. H.; Brandt, J.; Hertel, O.
A 3-D Eulerian transport-chemistry model based on modules and parameterisations from models developed over the last decade at the National Environmental Research Institute (DREAM, DEHM, ACDEP and DEOM) has been developed. The model is hemispheric with currently two nests implemented. The horizontal resolution in the mother domain is 150 km x 150 km. First nest covers the European area wit,h a 50 km x 50 km resolution, second covers the Scandinavian area with a resolution of 16.67 km x 16.67 km. The model employs a chemical scheme (originally 53 species) which has been modified to include a detailed description of the nitrogen chemistry. The concentration of air pollutants, such as sulfur and nitrogen in various forms, has been calculated with the model, applying no nesting as well as one and two nests. The calculated values have been validated by comparison to measurements from more than 200 EMEP monitoring stations. Furthermore deposition of nitrogen to marine waters has been estimated with the model. The goal is to obtain an improved description of spatial and temporal variations in the nutrient deposition to the marine environment. In the presentation the physics and chemistry of the model will be shortly described. Validations of the model calculations by comparison to EMEP measurements will be shown and discussed together with the results of the deposition calculations.
A material model driver for DYNA3D
Hallquist, J.O.; Whirley, R.G.
1990-02-22
This report describes a material model driver which has recently been implemented in the DYNA3D code. The material model driver allows plotting of the constitutive response predicted by a material model under a given load path. This capability is particularly useful when fitting complex material models to experimental data. The plotting capability of the material model driver facilitates comparison of the simulated material stress-strain behavior with actual material test results. 1 ref., 6 figs., 4 tabs.
Seismic modeling of Earth's 3D structure: Recent advancements
NASA Astrophysics Data System (ADS)
Ritsema, J.
2008-12-01
Global models of Earth's seismic structure continue to improve due to the growth of seismic data sets, implementation of advanced wave propagations theories, and increased computational power. In my presentation, I will summarize seismic tomography results from the past 5-10 years. I will compare the most recent P and S velocity models, discuss model resolution and model interpretation, and present an, admittedly biased, list of research directions required to develop the next generation 3D models.
Development of a three-dimensional time-dependent flow field model
NASA Technical Reports Server (NTRS)
Farmer, R. C.; Waldrop, W. R.; Pitts, F. H.; Shah, K. R.
1975-01-01
A three-dimensional, time-dependent mathematical model to represent Mobile Bay was developed. Computer programs were developed which numerically solve the appropriate conservation equations for predicting bay and estuary flow fields. The model is useful for analyzing the dispersion of sea water into fresh water and the transport of sediment, and for relating field and physical model data.
LIME: 3D visualisation and interpretation of virtual geoscience models
NASA Astrophysics Data System (ADS)
Buckley, Simon; Ringdal, Kari; Dolva, Benjamin; Naumann, Nicole; Kurz, Tobias
2017-04-01
Three-dimensional and photorealistic acquisition of surface topography, using methods such as laser scanning and photogrammetry, has become widespread across the geosciences over the last decade. With recent innovations in photogrammetric processing software, robust and automated data capture hardware, and novel sensor platforms, including unmanned aerial vehicles, obtaining 3D representations of exposed topography has never been easier. In addition to 3D datasets, fusion of surface geometry with imaging sensors, such as multi/hyperspectral, thermal and ground-based InSAR, and geophysical methods, create novel and highly visual datasets that provide a fundamental spatial framework to address open geoscience research questions. Although data capture and processing routines are becoming well-established and widely reported in the scientific literature, challenges remain related to the analysis, co-visualisation and presentation of 3D photorealistic models, especially for new users (e.g. students and scientists new to geomatics methods). Interpretation and measurement is essential for quantitative analysis of 3D datasets, and qualitative methods are valuable for presentation purposes, for planning and in education. Motivated by this background, the current contribution presents LIME, a lightweight and high performance 3D software for interpreting and co-visualising 3D models and related image data in geoscience applications. The software focuses on novel data integration and visualisation of 3D topography with image sources such as hyperspectral imagery, logs and interpretation panels, geophysical datasets and georeferenced maps and images. High quality visual output can be generated for dissemination purposes, to aid researchers with communication of their research results. The background of the software is described and case studies from outcrop geology, in hyperspectral mineral mapping and geophysical-geospatial data integration are used to showcase the novel
Geospatial Modelling Approach for 3d Urban Densification Developments
NASA Astrophysics Data System (ADS)
Koziatek, O.; Dragićević, S.; Li, S.
2016-06-01
With growing populations, economic pressures, and the need for sustainable practices, many urban regions are rapidly densifying developments in the vertical built dimension with mid- and high-rise buildings. The location of these buildings can be projected based on key factors that are attractive to urban planners, developers, and potential buyers. Current research in this area includes various modelling approaches, such as cellular automata and agent-based modelling, but the results are mostly linked to raster grids as the smallest spatial units that operate in two spatial dimensions. Therefore, the objective of this research is to develop a geospatial model that operates on irregular spatial tessellations to model mid- and high-rise buildings in three spatial dimensions (3D). The proposed model is based on the integration of GIS, fuzzy multi-criteria evaluation (MCE), and 3D GIS-based procedural modelling. Part of the City of Surrey, within the Metro Vancouver Region, Canada, has been used to present the simulations of the generated 3D building objects. The proposed 3D modelling approach was developed using ESRI's CityEngine software and the Computer Generated Architecture (CGA) language.
Parallel Optimization of 3D Cardiac Electrophysiological Model Using GPU.
Xia, Yong; Wang, Kuanquan; Zhang, Henggui
2015-01-01
Large-scale 3D virtual heart model simulations are highly demanding in computational resources. This imposes a big challenge to the traditional computation resources based on CPU environment, which already cannot meet the requirement of the whole computation demands or are not easily available due to expensive costs. GPU as a parallel computing environment therefore provides an alternative to solve the large-scale computational problems of whole heart modeling. In this study, using a 3D sheep atrial model as a test bed, we developed a GPU-based simulation algorithm to simulate the conduction of electrical excitation waves in the 3D atria. In the GPU algorithm, a multicellular tissue model was split into two components: one is the single cell model (ordinary differential equation) and the other is the diffusion term of the monodomain model (partial differential equation). Such a decoupling enabled realization of the GPU parallel algorithm. Furthermore, several optimization strategies were proposed based on the features of the virtual heart model, which enabled a 200-fold speedup as compared to a CPU implementation. In conclusion, an optimized GPU algorithm has been developed that provides an economic and powerful platform for 3D whole heart simulations.
Parallel Optimization of 3D Cardiac Electrophysiological Model Using GPU
Xia, Yong; Zhang, Henggui
2015-01-01
Large-scale 3D virtual heart model simulations are highly demanding in computational resources. This imposes a big challenge to the traditional computation resources based on CPU environment, which already cannot meet the requirement of the whole computation demands or are not easily available due to expensive costs. GPU as a parallel computing environment therefore provides an alternative to solve the large-scale computational problems of whole heart modeling. In this study, using a 3D sheep atrial model as a test bed, we developed a GPU-based simulation algorithm to simulate the conduction of electrical excitation waves in the 3D atria. In the GPU algorithm, a multicellular tissue model was split into two components: one is the single cell model (ordinary differential equation) and the other is the diffusion term of the monodomain model (partial differential equation). Such a decoupling enabled realization of the GPU parallel algorithm. Furthermore, several optimization strategies were proposed based on the features of the virtual heart model, which enabled a 200-fold speedup as compared to a CPU implementation. In conclusion, an optimized GPU algorithm has been developed that provides an economic and powerful platform for 3D whole heart simulations. PMID:26581957
3D Model Generation From the Engineering Drawing
NASA Astrophysics Data System (ADS)
Vaský, Jozef; Eliáš, Michal; Bezák, Pavol; Červeňanská, Zuzana; Izakovič, Ladislav
2010-01-01
The contribution deals with the transformation of engineering drawings in a paper form into a 3D computer representation. A 3D computer model can be further processed in CAD/CAM system, it can be modified, archived, and a technical drawing can be then generated from it as well. The transformation process from paper form to the data one is a complex and difficult one, particularly owing to the different types of drawings, forms of displayed objects and encountered errors and deviations from technical standards. The algorithm for 3D model generating from an orthogonal vector input representing a simplified technical drawing of the rotational part is described in this contribution. The algorithm was experimentally implemented as ObjectARX application in the AutoCAD system and the test sample as the representation of the rotational part was used for verificaton.
3-D world modeling for an autonomous robot
Goldstein, M.; Pin, F.G.; Weisbin, C.R.
1987-08-01
This paper presents a methodology for a concise representation of the 3-D world model for a mobile robot, using range data. The process starts with the segmentation of the scene into ''objects'' that are given a unique label, based on principles of range continuity. Then the external surface of each object is partitioned into homogeneous surface patches. Contours of surface patches in 3-D space are identified by estimating the normal and curvature associated with each pixel. The resulting surface patches are then classified as planar, convex or concave. Since the world model uses a volumetric representation for the 3-D environment, planar surfaces are represented by thin volumetric polyhedra. Spherical and cylindrical surfaces are extracted and represented by appropriate volumetric primitives. All other surfaces are represented using the boolean union of spherical volumes (as described in a separate paper by the same authors). The result is a general, concise representation of the external 3-D world, which allows for efficient and robust 3-D object recognition. 20 refs., 14 figs.
Space Partitioning for Privacy Enabled 3D City Models
NASA Astrophysics Data System (ADS)
Filippovska, Y.; Wichmann, A.; Kada, M.
2016-10-01
Due to recent technological progress, data capturing and processing of highly detailed (3D) data has become extensive. And despite all prospects of potential uses, data that includes personal living spaces and public buildings can also be considered as a serious intrusion into people's privacy and a threat to security. It becomes especially critical if data is visible by the general public. Thus, a compromise is needed between open access to data and privacy requirements which can be very different for each application. As privacy is a complex and versatile topic, the focus of this work particularly lies on the visualization of 3D urban data sets. For the purpose of privacy enabled visualizations of 3D city models, we propose to partition the (living) spaces into privacy regions, each featuring its own level of anonymity. Within each region, the depicted 2D and 3D geometry and imagery is anonymized with cartographic generalization techniques. The underlying spatial partitioning is realized as a 2D map generated as a straight skeleton of the open space between buildings. The resulting privacy cells are then merged according to the privacy requirements associated with each building to form larger regions, their borderlines smoothed, and transition zones established between privacy regions to have a harmonious visual appearance. It is exemplarily demonstrated how the proposed method generates privacy enabled 3D city models.
Motion of magnetospheric particle clouds in a time-dependent electric field model
NASA Technical Reports Server (NTRS)
Roederer, J. G.; Hones, E. H., Jr.
1974-01-01
A computer code has been developed to study quantitatively the drift motion of magnetospheric particles in a time-dependent electric field. These calculations were applied to the case of proton and electron injections from the plasma sheet during substorms; the model predictions were checked against observations on board the geosynchronous satellite ATS 5 by DeForest and McIlwain (1971). It was found that it is possible to simulate the observed proton spectrograms with an adequate choice of a time-dependent electric field model. The resulting kinematics is physically quite simple and in its gross features does not depend too strongly on the particular fine structure of the model.
Long-lifetime Martian orbit selection using a time-dependent model of the Martian atmosphere
NASA Technical Reports Server (NTRS)
Culp, R. D.; Stewart, A. I.; Chow, C.-C.; Uphoff, C.
1984-01-01
A mathematical model of the time-dependent Martian atmosphere has been developed in order to accurately calculate the effects of aerodynamic drag on a low altitude satellite. The time-dependent properties of the model include solar activity effects, dust storm effects, seasonal and diurnal variations, and annual motion effects. Position effects are accounted for through Martian latitude and longitude. Expected values of mass density, temperature, scale height, and the estimated standard deviation of the mass density are provided. An example of the use of the model in selecting an orbit for the Mars Geochemical/Climatology Orbiter is given.
Coronal roots of solar wind streams: 3-D MHD modeling
NASA Technical Reports Server (NTRS)
Pisanko, Yu. V.
1995-01-01
Weak (discontinuous) solutions of the 3-D MHD equations look like a promising tool to model the transonic solar wind with structural elements: current sheets, coronal plumes etc. Using the observational information about various coronal emissions one can include these structural elements into the 3-D MHD solar wind model by embedding the discontinuities of given type. Such 3-D MHD structured solar wind is calculated self-consistently: variants are examined via numerical experiments. In particular, the behavior of coronal plumes in the transonic solar wind flow, is modeled. The input information for numerical modeling (for example, the magnetic field map at the very base of the solar corona) can be adjusted so that fast stream arises over the center of the coronal hole, over the coronal hole boundaries and, even, over the region with closed magnetic topology. 3-D MHD equations have the analytical solution which can serve as a model of supersonic trans-alfvenic solar wind in the (5-20) solar radii heliocentric distance interval. The transverse, nonradial total (gas + magnetic field) pressure balance in the flow is the corner-stone of this solution. The solution describes the filamentation (ray-like structure of the solar corona) and streaming (formation of high-speed streams with velocities up to 800 km/sec) as a consequence of the magnetic field spatial inhomogeneous structure and trans-alfvenic character of the flow. The magnetic field works in the model as a 'controller' for the solar wind streaming and filamentation.
3D shape decomposition and comparison for gallbladder modeling
NASA Astrophysics Data System (ADS)
Huang, Weimin; Zhou, Jiayin; Liu, Jiang; Zhang, Jing; Yang, Tao; Su, Yi; Law, Gim Han; Chui, Chee Kong; Chang, Stephen
2011-03-01
This paper presents an approach to gallbladder shape comparison by using 3D shape modeling and decomposition. The gallbladder models can be used for shape anomaly analysis and model comparison and selection in image guided robotic surgical training, especially for laparoscopic cholecystectomy simulation. The 3D shape of a gallbladder is first represented as a surface model, reconstructed from the contours segmented in CT data by a scheme of propagation based voxel learning and classification. To better extract the shape feature, the surface mesh is further down-sampled by a decimation filter and smoothed by a Taubin algorithm, followed by applying an advancing front algorithm to further enhance the regularity of the mesh. Multi-scale curvatures are then computed on the regularized mesh for the robust saliency landmark localization on the surface. The shape decomposition is proposed based on the saliency landmarks and the concavity, measured by the distance from the surface point to the convex hull. With a given tolerance the 3D shape can be decomposed and represented as 3D ellipsoids, which reveal the shape topology and anomaly of a gallbladder. The features based on the decomposed shape model are proposed for gallbladder shape comparison, which can be used for new model selection. We have collected 19 sets of abdominal CT scan data with gallbladders, some shown in normal shape and some in abnormal shapes. The experiments have shown that the decomposed shapes reveal important topology features.
3D modeling of dual-gate FinFET.
Mil'shtein, Samson; Devarakonda, Lalitha; Zanchi, Brian; Palma, John
2012-11-13
The tendency to have better control of the flow of electrons in a channel of field-effect transistors (FETs) did lead to the design of two gates in junction field-effect transistors, field plates in a variety of metal semiconductor field-effect transistors and high electron mobility transistors, and finally a gate wrapping around three sides of a narrow fin-shaped channel in a FinFET. With the enhanced control, performance trends of all FETs are still challenged by carrier mobility dependence on the strengths of the electrical field along the channel. However, in cases when the ratio of FinFET volume to its surface dramatically decreases, one should carefully consider the surface boundary conditions of the device. Moreover, the inherent non-planar nature of a FinFET demands 3D modeling for accurate analysis of the device performance. Using the Silvaco modeling tool with quantization effects, we modeled a physical FinFET described in the work of Hisamoto et al. (IEEE Tran. Elec. Devices 47:12, 2000) in 3D. We compared it with a 2D model of the same device. We demonstrated that 3D modeling produces more accurate results. As 3D modeling results came close to experimental measurements, we made the next step of the study by designing a dual-gate FinFET biased at Vg1 >Vg2. It is shown that the dual-gate FinFET carries higher transconductance than the single-gate device.
Enhanced visualization of angiograms using 3D models
NASA Astrophysics Data System (ADS)
Marovic, Branko S.; Duckwiler, Gary R.; Villablanca, Pablo; Valentino, Daniel J.
1999-05-01
The 3D visualization of intracranial vasculature can facilitate the planning of endovascular therapy and the evaluation of interventional result. To create 3D visualizations, volumetric datasets from x-ray computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are commonly rendered using maximum intensity projection (MIP), volume rendering, or surface rendering techniques. However, small aneurysms and mild stenoses are very difficult to detect using these methods. Furthermore, the instruments used during endovascular embolization or surgical treatment produce artifacts that typically make post-intervention CTA inapplicable, and the presence of magnetic material prohibits the use of MRA. Therefore, standard digital angiography is typically used. In order to address these problems, we developed a visualization and modeling system that displays 2D and 3D angiographic images using a simple Web-based interface. Polygonal models of vasculature were generated from CT and MR data using 3D segmentation of bones and vessels and polygonal surface extraction and simplification. A web-based 3D environment was developed for interactive examination of reconstructed surface models, creation of oblique cross- sections and maximum intensity projections, and distance measurements and annotations. This environment uses a multi- tier client/server approach employing VRML and Java. The 3D surface model and angiographic images can be aligned and displayed simultaneously to permit better perception of complex vasculature and to determine optical viewing positions and angles before starting an angiographic sessions. Polygonal surface reconstruction allows interactive display of complex spatial structures on inexpensive platforms such as personal computers as well as graphic workstations. The aneurysm assessment procedure demonstrated the utility of web-based technology for clinical visualization. The resulting system facilitated the treatment of serious vascular
3-D QSAutogrid/R: an alternative procedure to build 3-D QSAR models. Methodologies and applications.
Ballante, Flavio; Ragno, Rino
2012-06-25
Since it first appeared in 1988 3-D QSAR has proved its potential in the field of drug design and activity prediction. Although thousands of citations now exist in 3-D QSAR, its development was rather slow with the majority of new 3-D QSAR applications just extensions of CoMFA. An alternative way to build 3-D QSAR models, based on an evolution of software, has been named 3-D QSAutogrid/R and has been developed to use only software freely available to academics. 3-D QSAutogrid/R covers all the main features of CoMFA and GRID/GOLPE with implementation by multiprobe/multiregion variable selection (MPGRS) that improves the simplification of interpretation of the 3-D QSAR map. The methodology is based on the integration of the molecular interaction fields as calculated by AutoGrid and the R statistical environment that can be easily coupled with many free graphical molecular interfaces such as UCSF-Chimera, AutoDock Tools, JMol, and others. The description of each R package is reported in detail, and, to assess its validity, 3-D QSAutogrid/R has been applied to three molecular data sets of which either CoMFA or GRID/GOLPE models were reported in order to compare the results. 3-D QSAutogrid/R has been used as the core engine to prepare more that 240 3-D QSAR models forming the very first 3-D QSAR server ( www.3d-qsar.com ) with its code freely available through R-Cran distribution.
NASA Astrophysics Data System (ADS)
Sharkawi, K.-H.; Abdul-Rahman, A.
2013-09-01
Cities and urban areas entities such as building structures are becoming more complex as the modern human civilizations continue to evolve. The ability to plan and manage every territory especially the urban areas is very important to every government in the world. Planning and managing cities and urban areas based on printed maps and 2D data are getting insufficient and inefficient to cope with the complexity of the new developments in big cities. The emergence of 3D city models have boosted the efficiency in analysing and managing urban areas as the 3D data are proven to represent the real world object more accurately. It has since been adopted as the new trend in buildings and urban management and planning applications. Nowadays, many countries around the world have been generating virtual 3D representation of their major cities. The growing interest in improving the usability of 3D city models has resulted in the development of various tools for analysis based on the 3D city models. Today, 3D city models are generated for various purposes such as for tourism, location-based services, disaster management and urban planning. Meanwhile, modelling 3D objects are getting easier with the emergence of the user-friendly tools for 3D modelling available in the market. Generating 3D buildings with high accuracy also has become easier with the availability of airborne Lidar and terrestrial laser scanning equipments. The availability and accessibility to this technology makes it more sensible to analyse buildings in urban areas using 3D data as it accurately represent the real world objects. The Open Geospatial Consortium (OGC) has accepted CityGML specifications as one of the international standards for representing and exchanging spatial data, making it easier to visualize, store and manage 3D city models data efficiently. CityGML able to represents the semantics, geometry, topology and appearance of 3D city models in five well-defined Level-of-Details (LoD), namely LoD0
Creating Physical 3D Stereolithograph Models of Brain and Skull
Kelley, Daniel J.; Farhoud, Mohammed; Meyerand, M. Elizabeth; Nelson, David L.; Ramirez, Lincoln F.; Dempsey, Robert J.; Wolf, Alan J.; Alexander, Andrew L.; Davidson, Richard J.
2007-01-01
The human brain and skull are three dimensional (3D) anatomical structures with complex surfaces. However, medical images are often two dimensional (2D) and provide incomplete visualization of structural morphology. To overcome this loss in dimension, we developed and validated a freely available, semi-automated pathway to build 3D virtual reality (VR) and hand-held, stereolithograph models. To evaluate whether surface visualization in 3D was more informative than in 2D, undergraduate students (n = 50) used the Gillespie scale to rate 3D VR and physical models of both a living patient-volunteer's brain and the skull of Phineas Gage, a historically famous railroad worker whose misfortune with a projectile tamping iron provided the first evidence of a structure-function relationship in brain. Using our processing pathway, we successfully fabricated human brain and skull replicas and validated that the stereolithograph model preserved the scale of the VR model. Based on the Gillespie ratings, students indicated that the biological utility and quality of visual information at the surface of VR and stereolithograph models were greater than the 2D images from which they were derived. The method we developed is useful to create VR and stereolithograph 3D models from medical images and can be used to model hard or soft tissue in living or preserved specimens. Compared to 2D images, VR and stereolithograph models provide an extra dimension that enhances both the quality of visual information and utility of surface visualization in neuroscience and medicine. PMID:17971879
Embedding 3D models of biological specimens in PDF publications.
Ruthensteiner, Bernhard; Hess, Martin
2008-11-01
By providing two examples, the option for embedding 3D models in electronic versions of life science publications is presented. These examples, presumably representing the first such models published, are developmental stages of an evertebrate (Patella caerulea, Mollusca) and a vertebrate species (Psetta maxima, Teleostei) obtained from histological section series reconstruction processed with the software package Amira. These surface rendering models are particularly suitable for a PDF file because they can easily be transformed to a file format required and components may be conveniently combined and hierarchically arranged. All methodological steps starting from specimen preparation until embedding of resulting models in PDF files with emphasis on conversion of Amira data to the appropriate 3D file format are explained. Usability of 3D models in PDF documents is exemplified and advantages over 2D illustrations are discussed, including better explanation capabilities for spatial arrangements, higher information contents, and limiting options for disguising results by authors. Possibilities for additional applications reaching far beyond the examples presented are suggested. Problems such as long-term compatibility of file format and hardware plus software, editing and embedding of files, file size and differences in information contents between printed and electronic version will likely be overcome by technical development and increasing tendency toward electronic at the cost of printed publications. Since 3D visualization plays an increasing role in manifold disciplines of science and appropriate tools for the popular PDF format are readily available, we propose routine application of this way of illustration in electronic life science papers.
Enhanced LOD Concepts for Virtual 3d City Models
NASA Astrophysics Data System (ADS)
Benner, J.; Geiger, A.; Gröger, G.; Häfele, K.-H.; Löwner, M.-O.
2013-09-01
Virtual 3D city models contain digital three dimensional representations of city objects like buildings, streets or technical infrastructure. Because size and complexity of these models continuously grow, a Level of Detail (LoD) concept effectively supporting the partitioning of a complete model into alternative models of different complexity and providing metadata, addressing informational content, complexity and quality of each alternative model is indispensable. After a short overview on various LoD concepts, this paper discusses the existing LoD concept of the CityGML standard for 3D city models and identifies a number of deficits. Based on this analysis, an alternative concept is developed and illustrated with several examples. It differentiates between first, a Geometric Level of Detail (GLoD) and a Semantic Level of Detail (SLoD), and second between the interior building and its exterior shell. Finally, a possible implementation of the new concept is demonstrated by means of an UML model.
Teaching the geological subsurface with 3D models
NASA Astrophysics Data System (ADS)
Thorpe, Steve; Ward, Emma
2014-05-01
3D geological models have great potential as a resource when teaching geological concepts as it allows the student to visualise and interrogate UK geology. They are especially useful when dealing with the conversion of 2D field, map and GIS outputs into three dimensional geological units, which is a common problem for many students. Today's earth science students use a variety of skills and processes during their learning experience including spatial thinking, image construction, detecting patterns, making predictions and deducing the orientation of themselves. 3D geological models can reinforce spatial thinking strategies and encourage students to think about processes and properties, in turn helping the student to recognise pre-learnt geological principles in the field and to convert what they see at the surface into a picture of what is going on at depth. The British Geological Survey (BGS) has been producing digital 3D geological models for over 10 years. The models produced are revolutionising the working practices, data standards and products of the BGS. Sharing our geoscience information with academia is highlighted throughout the BGS strategy as is instilling practical skills in future geoscience professionals, such as model building and interpretation. In 2009 a project was launched to investigate the potential of the models as a teaching resource. The study included justifying if and how the models help students to learn, how models have been used historically, and how other forms of modelling are being used today. BGS now produce 3D geological models for use by anyone teaching or learning geoscience. They incorporate educational strategies that will develop geospatial skills and alleviate potential problems that some students experience. They are contained within contemporary case studies and show standard geological concepts, structures, sedimentary rocks, cross sections and field techniques. 3D geological models of the Isle of Wight and Ingleborough
3D Geological Model for "LUSI" - a Deep Geothermal System
NASA Astrophysics Data System (ADS)
Sohrabi, Reza; Jansen, Gunnar; Mazzini, Adriano; Galvan, Boris; Miller, Stephen A.
2016-04-01
Geothermal applications require the correct simulation of flow and heat transport processes in porous media, and many of these media, like deep volcanic hydrothermal systems, host a certain degree of fracturing. This work aims to understand the heat and fluid transport within a new-born sedimentary hosted geothermal system, termed Lusi, that began erupting in 2006 in East Java, Indonesia. Our goal is to develop conceptual and numerical models capable of simulating multiphase flow within large-scale fractured reservoirs such as the Lusi region, with fractures of arbitrary size, orientation and shape. Additionally, these models can also address a number of other applications, including Enhanced Geothermal Systems (EGS), CO2 sequestration (Carbon Capture and Storage CCS), and nuclear waste isolation. Fractured systems are ubiquitous, with a wide-range of lengths and scales, making difficult the development of a general model that can easily handle this complexity. We are developing a flexible continuum approach with an efficient, accurate numerical simulator based on an appropriate 3D geological model representing the structure of the deep geothermal reservoir. Using previous studies, borehole information and seismic data obtained in the framework of the Lusi Lab project (ERC grant n°308126), we present here the first 3D geological model of Lusi. This model is calculated using implicit 3D potential field or multi-potential fields, depending on the geological context and complexity. This method is based on geological pile containing the geological history of the area and relationship between geological bodies allowing automatic computation of intersections and volume reconstruction. Based on the 3D geological model, we developed a new mesh algorithm to create hexahedral octree meshes to transfer the structural geological information for 3D numerical simulations to quantify Thermal-Hydraulic-Mechanical-Chemical (THMC) physical processes.
A time-dependent diffusion convection model for the long term modulation of cosmic rays
NASA Technical Reports Server (NTRS)
Gallagher, J. J.
1974-01-01
A model is developed which incorporates to first order the direct effects of the time dependent diffusive propagation of interstellar cosmic rays in a slowly changing interplanetary medium. The model provides a physical explanation for observed rigidity-dependent phase lags in modulated spectra (cosmic ray hysteresis). The average distance to the modulating boundary during the last solar cycle is estimated.
Performance and Cognitive Assessment in 3-D Modeling
ERIC Educational Resources Information Center
Fahrer, Nolan E.; Ernst, Jeremy V.; Branoff, Theodore J.; Clark, Aaron C.
2011-01-01
The purpose of this study was to investigate identifiable differences between performance and cognitive assessment scores in a 3-D modeling unit of an engineering drafting course curriculum. The study aimed to provide further investigation of the need of skill-based assessments in engineering/technical graphics courses to potentially increase…
Modeling the Properties of 3D Woven Composites
NASA Technical Reports Server (NTRS)
Cox, Brian N.
1995-01-01
An extensive study has been completed of the internal geometry, the mechanisms of failure, and the micromechanics of local failure events in graphite/epoxy composites with three dimensional (3D) woven reinforcement. This work has led to the development of models for predicting elastic constants, strength, notch sensitivity, and fatigue life. A summary is presented here.
Modeling the Properties of 3D Woven Composites
NASA Technical Reports Server (NTRS)
Cox, Brian N.
1995-01-01
An extensive study has been completed of the internal geometry, the mechanisms of failure, and the micromechanics of local failure events in graphite/epoxy composites with three dimensional (3D) woven reinforcement. This work has led to the development of models for predicting elastic constants, strength, notch sensitivity, and fatigue life. A summary is presented here.
A Sketching Interface for Freeform 3D Modeling
NASA Astrophysics Data System (ADS)
Igarashi, Takeo
This chapter introduces Teddy, a sketch-based modeling system to quickly and easily design freeform models such as stuffed animals and other rotund objects. The user draws several 2D freeform strokes interactively on the screen and the system automatically constructs plausible 3D polygonal surfaces. Our system supports several modeling operations, including the operation to construct a 3D polygonal surface from a 2D silhouette drawn by the user: it inflates the region surrounded by the silhouette making a wide area fat, and a narrow area thin. Teddy, our prototype system, is implemented as a Java program, and the mesh construction is done in real-time on a standard PC. Our informal user study showed that a first-time user masters the operations within 10 minutes, and can construct interesting 3D models within minutes. We also report the result of a case study where a high school teacher taught various 3D concepts in geography using the system.
Tracking people and cars using 3D modeling and CCTV.
Edelman, Gerda; Bijhold, Jurrien
2010-10-10
The aim of this study was to find a method for the reconstruction of movements of people and cars using CCTV footage and a 3D model of the environment. A procedure is proposed, in which video streams are synchronized and displayed in a 3D model, by using virtual cameras. People and cars are represented by cylinders and boxes, which are moved in the 3D model, according to their movements as shown in the video streams. The procedure was developed and tested in an experimental setup with test persons who logged their GPS coordinates as a recording of the ground truth. Results showed that it is possible to implement this procedure and to reconstruct movements of people and cars from video recordings. The procedure was also applied to a forensic case. In this work we experienced that more situational awareness was created by the 3D model, which made it easier to track people on multiple video streams. Based on all experiences from the experimental set up and the case, recommendations are formulated for use in practice.
Assessment of 3D Models Used in Contours Studies
ERIC Educational Resources Information Center
Alvarez, F. J. Ayala; Parra, E. B. Blazquez; Tubio, F. Montes
2015-01-01
This paper presents an experimental research focusing on the view of first year students. The aim is to check the quality of implementing 3D models integrated in the curriculum. We search to determine students' preference between the various means facilitated in order to understand the given subject. Students have been respondents to prove the…
Coarse-grained modeling of RNA 3D structure.
Dawson, Wayne K; Maciejczyk, Maciej; Jankowska, Elzbieta J; Bujnicki, Janusz M
2016-07-01
Functional RNA molecules depend on three-dimensional (3D) structures to carry out their tasks within the cell. Understanding how these molecules interact to carry out their biological roles requires a detailed knowledge of RNA 3D structure and dynamics as well as thermodynamics, which strongly governs the folding of RNA and RNA-RNA interactions as well as a host of other interactions within the cellular environment. Experimental determination of these properties is difficult, and various computational methods have been developed to model the folding of RNA 3D structures and their interactions with other molecules. However, computational methods also have their limitations, especially when the biological effects demand computation of the dynamics beyond a few hundred nanoseconds. For the researcher confronted with such challenges, a more amenable approach is to resort to coarse-grained modeling to reduce the number of data points and computational demand to a more tractable size, while sacrificing as little critical information as possible. This review presents an introduction to the topic of coarse-grained modeling of RNA 3D structures and dynamics, covering both high- and low-resolution strategies. We discuss how physics-based approaches compare with knowledge based methods that rely on databases of information. In the course of this review, we discuss important aspects in the reasoning process behind building different models and the goals and pitfalls that can result.
Comparison of electrostatic and time dependent simulation codes for modeling a pulsed power gun
Srinivasan-Rao, T.; Smedley, J.; Batchelor, K.; Farrell, J.P.; Dudnikova, G.
1998-06-01
This paper is a result of a group of simulations used to determine the optimal parameters for a pulsed power electron gun. As electrostatic codes such as PBGUNS tend to be cheaper, easier to use, and have less stringent computational requirements than time dependent codes such as MAFIA, it was desirable to determine those regimes in which the electrostatic codes agree with time dependent models. It was also necessary to identify those problems that required time dependence, such as longitudinal variation in an electron bunch. PBGUNS was then used to perform the bulk of the optimization, with only those issues that required time dependence being resolved with MAFIA. Good agreement in transverse phase space values was found between the electrostatic code (PBGUNS) and the time dependent code (MAFIA) for a variety of pulse durations, even for pulse durations short compared to the electron transit time of the accelerating region. To obtain values for the longitudinal energy spread and the variation of the transverse phase space across the bunch, it was necessary to use MAFIA. The electrostatic codes have an advantage in terms of required computational resources and run time, and are therefore a good choice for modeling jobs in which the longitudinal energy spread is unimportant.
Comparing predictions among competing risks models with time-dependent covariates
Cortese, Giuliana; Gerds, Thomas A.; Andersen, Per K.
2013-01-01
Prediction of cumulative incidences is often a primary goal in clinical studies with several end-points. We compare predictions among competing risks models with time-dependent covariates. For a series of landmark time points we study the predictive accuracy of a multi-state regression model, where the time-dependent covariate represents an intermediate state and two alternative landmark approaches (Cortese & Andersen, 2010). At each landmark time point, the prediction performance is measured as the t-year expected Brier score where pseudovalues are constructed in order to deal with right censored event times. We apply the methods to data from a bone marrow transplant study where graft versus host disease (GvHD) is considered a time-dependent covariate for predicting relapse and death in remission. PMID:23494745
3D for Geosciences: Interactive Tangibles and Virtual Models
NASA Astrophysics Data System (ADS)
Pippin, J. E.; Matheney, M.; Kitsch, N.; Rosado, G.; Thompson, Z.; Pierce, S. A.
2016-12-01
Point cloud processing provides a method of studying and modelling geologic features relevant to geoscience systems and processes. Here, software including Skanect, MeshLab, Blender, PDAL, and PCL are used in conjunction with 3D scanning hardware, including a Structure scanner and a Kinect camera, to create and analyze point cloud images of small scale topography, karst features, tunnels, and structures at high resolution. This project successfully scanned internal karst features ranging from small stalactites to large rooms, as well as an external waterfall feature. For comparison purposes, multiple scans of the same object were merged into single object files both automatically, using commercial software, and manually using open source libraries and code. Files with format .ply were manually converted into numeric data sets to be analyzed for similar regions between files in order to match them together. We can assume a numeric process would be more powerful and efficient than the manual method, however it could lack other useful features that GUI's may have. The digital models have applications in mining as efficient means of replacing topography functions such as measuring distances and areas. Additionally, it is possible to make simulation models such as drilling templates and calculations related to 3D spaces. Advantages of using methods described here for these procedures include the relatively quick time to obtain data and the easy transport of the equipment. With regard to openpit mining, obtaining 3D images of large surfaces and with precision would be a high value tool by georeferencing scan data to interactive maps. The digital 3D images obtained from scans may be saved as printable files to create physical 3D-printable models to create tangible objects based on scientific information, as well as digital "worlds" able to be navigated virtually. The data, models, and algorithms explored here can be used to convey complex scientific ideas to a range of
Use Models like Maps in a 3D SDI
NASA Astrophysics Data System (ADS)
Gietzel, Jan; Gabriel, Paul; Schaeben, Helmut; Le, Hai Ha
2013-04-01
Digital geological applications have become 3D up to 4D modelling of the underground. The modellers are working very heterogeneously in terms of its applied software systems. On the other hand the 3D/4D modelling of the subsurface has become part of the geological surveys all around the world. This implies a wide spread group of users working in different institutions aiming to work together on one subsurface model. Established 3D/4D-modelling software systems mainly use a file based approach to store data, which is in a high contrast to the needs of a central administrated and network based data transfer approach. At the department of geophysics and geo information sciences at the Technical University Bergakademie Freiberg, the GST system for managing 3D and 4D geosciences data in a databases system was developed and is now continued by the company GiGa infosystems. The GST-Framework includes a storage engine, a web service for sharing and a number of client software including a browser based client interface for visualising, accessing and manipulating geological CAD data. Including a check out system GST supports multi user editing on huge models, designed to manage seamless high resolution models of the subsurface. While working on complex projects various software is used for the creation of the model, the prediction of properties and final simulation. A problem rising from the use of several software is the interoperability of the models. Due to conversion errors different working groups use mainly different raw data. This results in different models, which have to be corrected with additional effort. One platform sharing the models is strongly demanded. One high potential solution is a centralized and software independent storage, which will be presented.
Robust 3D reconstruction system for human jaw modeling
NASA Astrophysics Data System (ADS)
Yamany, Sameh M.; Farag, Aly A.; Tazman, David; Farman, Allan G.
1999-03-01
This paper presents a model-based vision system for dentistry that will replace traditional approaches used in diagnosis, treatment planning and surgical simulation. Dentistry requires accurate 3D representation of the teeth and jaws for many diagnostic and treatment purposes. For example orthodontic treatment involves the application of force systems to teeth over time to correct malocclusion. In order to evaluate tooth movement progress, the orthodontists monitors this movement by means of visual inspection, intraoral measurements, fabrication of plastic models, photographs and radiographs, a process which is both costly and time consuming. In this paper an integrate system has been developed to record the patient's occlusion using computer vision. Data is acquired with an intraoral video camera. A modified shape from shading (SFS) technique, using perspective projection and camera calibration, is used to extract accurate 3D information from a sequence of 2D images of the jaw. A new technique for 3D data registration, using a Grid Closest Point transform and genetic algorithms, is used to register the SFS output. Triangulization is then performed, and a solid 3D model is obtained via a rapid prototype machine.
3D Geological modelling - towards a European level infrastructure
NASA Astrophysics Data System (ADS)
Lee, Kathryn A.; van der Krogt, Rob; Busschers, Freek S.
2013-04-01
The joint European Geological Surveys are preparing the ground for a "European Geological Data Infrastructure" (EGDI), under the framework of the FP7-project EGDI-Scope. This scoping study, started in June 2012, for a pan-European e-Infrastructure is based on the successes of earlier joint projects including 'OneGeology-Europe' and aims to provide the backbone for serving interoperable, geological data currently held by European Geological Surveys. Also data from past, ongoing and future European projects will be incorporated. The scope will include an investigation of the functional and technical requirements for serving 3D geological models and will look to research the potential for providing a framework to integrate models at different scales, and form a structure for enabling the development of new and innovative model delivery mechanisms. The EGDI-scope project encourages pan-European inter-disciplinary collaboration between all European Geological Surveys. It aims to enhance emerging web based technologies that will facilitate the delivery of geological data to user communities involved in European policy making and international industry, but also to geoscientific research communities and the general public. Therefore, stakeholder input and communication is imperative to the success, as is the collaboration with all the Geological Surveys of Europe. The most important functional and technical requirements for delivery of such information at pan-European level will be derived from exchanges with relevant European stakeholder representatives and providers of geological data. For handling and delivering 3D geological model data the project will need to address a number of strategic issues: • Which are the most important issues and queries for the relevant stakeholders, requiring 3D geological models? How can this be translated to functional requirements for development and design of an integrated European application? • How to handle the very large
NASA Astrophysics Data System (ADS)
Rahman, M. T.; Hossain, M. Mofazzal
2017-01-01
The time-dependent model of ion motion is used to propose an analytical model for dual frequency (DF) capacitively coupled plasma (CCP) sheath driven by a pulsed source and a radio-frequency source. In this model, the sheath is considered to be collisional. In this model, the time dependent terms of ion fluid equations are ignored, but the electric field, ion motion and ion density remain time dependent. Electron profile is assumed to be step-like. Analytical expressions for electron sheath width and sheath potential have been developed. The calculated sheath width and potential are compared with the dual radio frequency driven time dependent models of capacitively coupled plasma sheath. From the temporal evaluation of sheath motion and potential, it has been found that pulse driven sheath has higher sheath potential and sheath width than that of conventional radio frequency driven DF CCP. Moreover, it is also found that ion energy spread can be reduced using pulsed power. From the temporal investigation of sheath motion and potential, it has been found that the duty cycle of the pulse power significantly affects sheath width and sheath potential.
Quasi-3D Multi-scale Modeling Framework Development
NASA Astrophysics Data System (ADS)
Arakawa, A.; Jung, J.
2008-12-01
When models are truncated in or near an energetically active range of the spectrum, model physics must be changed as the resolution changes. The model physics of GCMs and that of CRMs are, however, quite different from each other and at present there is no unified formulation of model physics that automatically provides transition between these model physics. The Quasi-3D (Q3D) Multi-scale Modeling Framework (MMF) is an attempt to bridge this gap. Like the recently proposed Heterogeneous Multiscale Method (HMM) (E and Engquist 2003), MMF combines a macroscopic model, GCM, and a microscopic model, CRM. Unlike the traditional multiscale methods such as the multi-grid and adapted mesh refinement techniques, HMM and MMF are for solving multi-physics problems. They share the common objective "to design combined macroscopic-microscopic computational methods that are much more efficient than solving the full microscopic model and at the same time give the information we need" (E et al. 2008). The question is then how to meet this objective in practice, which can be highly problem dependent. In HHM, the efficiency is gained typically by localization of the microscale problem. Following the pioneering work by Grabowski and Smolarkiewicz (1999) and Grabowski (2001), MMF takes advantage of the fact that 2D CRMs are reasonably successful in simulating deep clouds. In this approach, the efficiency is gained by sacrificing the three-dimensionality of cloud-scale motion. It also "localizes" the algorithm through embedding a CRM in each GCM grid box using cyclic boundary condition. The Q3D MMF is an attempt to reduce the expense due to these constraints by partially including the cloud-scale 3D effects and extending the CRM beyond individual GCM grid boxes. As currently formulated, the Q3D MMF is a 4D estimation/prediction framework that combines a GCM with a 3D anelastic cloud-resolving vector vorticity equation model (VVM) applied to a network of horizontal grids. The network
RNA and protein 3D structure modeling: similarities and differences.
Rother, Kristian; Rother, Magdalena; Boniecki, Michał; Puton, Tomasz; Bujnicki, Janusz M
2011-09-01
In analogy to proteins, the function of RNA depends on its structure and dynamics, which are encoded in the linear sequence. While there are numerous methods for computational prediction of protein 3D structure from sequence, there have been very few such methods for RNA. This review discusses template-based and template-free approaches for macromolecular structure prediction, with special emphasis on comparison between the already tried-and-tested methods for protein structure modeling and the very recently developed "protein-like" modeling methods for RNA. We highlight analogies between many successful methods for modeling of these two types of biological macromolecules and argue that RNA 3D structure can be modeled using "protein-like" methodology. We also highlight the areas where the differences between RNA and proteins require the development of RNA-specific solutions.
Parallel 3-D viscoelastic finite difference seismic modelling
NASA Astrophysics Data System (ADS)
Bohlen, Thomas
2002-10-01
Computational power has advanced to a state where we can begin to perform wavefield simulations for realistic (complex) 3-D earth models at frequencies of interest to both seismologists and engineers. On serial platforms, however, 3-D calculations are still limited to small grid sizes and short seismic wave traveltimes. To make use of the efficiency of network computers a parallel 3-D viscoelastic finite difference (FD) code is implemented which allows to distribute the work on several PCs or workstations connected via standard ethernet in an in-house network. By using the portable message passing interface standard (MPI) for the communication between processors, running times can be reduced and grid sizes can be increased significantly. Furthermore, the code shows good performance on massive parallel supercomputers which makes the computation of very large grids feasible. This implementation greatly expands the applicability of the 3-D elastic/viscoelastic finite-difference modelling technique by providing an efficient, portable and practical C-program.
Stereoscopic display of 3D models for design visualization
NASA Astrophysics Data System (ADS)
Gilson, Kevin J.
2006-02-01
Advances in display technology and 3D design visualization applications have made real-time stereoscopic visualization of architectural and engineering projects a reality. Parsons Brinkerhoff (PB) is a transportation consulting firm that has used digital visualization tools from their inception and has helped pioneer the application of those tools to large scale infrastructure projects. PB is one of the first Architecture/Engineering/Construction (AEC) firms to implement a CAVE- an immersive presentation environment that includes stereoscopic rear-projection capability. The firm also employs a portable stereoscopic front-projection system, and shutter-glass systems for smaller groups. PB is using commercial real-time 3D applications in combination with traditional 3D modeling programs to visualize and present large AEC projects to planners, clients and decision makers in stereo. These presentations create more immersive and spatially realistic presentations of the proposed designs. This paper will present the basic display tools and applications, and the 3D modeling techniques PB is using to produce interactive stereoscopic content. The paper will discuss several architectural and engineering design visualizations we have produced.
NASA Astrophysics Data System (ADS)
Lasuik, J.; Shalchi, A.
2017-09-01
Recently, a new theory for the transport of energetic particles across a mean magnetic field was presented. Compared to other nonlinear theories the new approach has the advantage that it provides a full time-dependent description of the transport. Furthermore, a diffusion approximation is no longer part of that theory. The purpose of this paper is to combine this new approach with a time-dependent model for parallel transport and different turbulence configurations in order to explore the parameter regimes for which we get ballistic transport, compound subdiffusion, and normal Markovian diffusion.
3-D HYDRODYNAMIC MODELING IN A GEOSPATIAL FRAMEWORK
Bollinger, J; Alfred Garrett, A; Larry Koffman, L; David Hayes, D
2006-08-24
3-D hydrodynamic models are used by the Savannah River National Laboratory (SRNL) to simulate the transport of thermal and radionuclide discharges in coastal estuary systems. Development of such models requires accurate bathymetry, coastline, and boundary condition data in conjunction with the ability to rapidly discretize model domains and interpolate the required geospatial data onto the domain. To facilitate rapid and accurate hydrodynamic model development, SRNL has developed a pre- and post-processor application in a geospatial framework to automate the creation of models using existing data. This automated capability allows development of very detailed models to maximize exploitation of available surface water radionuclide sample data and thermal imagery.
Modeling of 3D Woven Composites Containing Multiple Delaminations
2012-08-20
researchers 3D woven composites shows better damage tolerance than laminated textile composites without z-yarns such as plain woven composites even...modeling of quasi-static short beam shear test of plain woven laminated composites. Cohesive elements were used in regions where transverse cracks and...Title ABSTRACT In this paper we present FE modeling of quasi-static short beam shear test of plain woven laminated composites. Cohesive elements were
Kallen Lehman approach to 3D Ising model
NASA Astrophysics Data System (ADS)
Canfora, F.
2007-03-01
A “Kallen-Lehman” approach to Ising model, inspired by quantum field theory à la Regge, is proposed. The analogy with the Kallen-Lehman representation leads to a formula for the free-energy of the 3D model with few free parameters which could be matched with the numerical data. The possible application of this scheme to the spin glass case is shortly discussed.
NASA Astrophysics Data System (ADS)
Mock, Samuel; Allenbach, Robin; Reynolds, Lance; Wehrens, Philip; Kurmann-Matzenauer, Eva; Kuhn, Pascal; Michael, Salomè; Di Tommaso, Gennaro; Herwegh, Marco
2016-04-01
The Swiss Molasse Basin comprises the western and central part of the North Alpine Foreland Basin. In recent years it has come under closer scrutiny due to its promising geopotentials such as geothermal energy and CO2 sequestration. In order to adress these topics good knowledge of the subsurface is a key prerequisite. For that matter, geological 3D models serve as valuable tools. In collaboration with the Swiss Geological Survey (swisstopo) and as part of the project GeoMol CH, a geological 3D model of the Swiss Molasse Basin in the Canton of Bern has been built. The model covers an area of 1810 km2and reaches depth of up to 6.7 km. It comprises 10 major Cenozoic and Mesozoic units and numerous faults. The 3D model is mainly based on 2D seismic data complemented by information from few deep wells. Additionally, data from geological maps and profiles were used for refinement at shallow depths. In total, 1163 km of reflection seismic data, along 77 seismic lines, have been interpreted by different authors with respect to stratigraphy and structures. Both, horizons and faults, have been interpreted in 2D and modelled in 3D using IHS's Kingdom Suite and Midland Valley's MOVE software packages, respectively. Given the variable degree of subsurface information available, each 3D model is subject of uncertainty. With the primary input data coming from interpretation of reflection seismic data, a variety of uncertainties comes into play. Some of them are difficult to address (e.g. author's style of interpretation) while others can be quantified (e.g. mis-tie correction, well-tie). An important source of uncertainties is the quality of seismic data; this affects the traceability and lateral continuation of seismic reflectors. By defining quality classes we can semi-quantify this source of uncertainty. In order to visualize the quality and density of the input data in a meaningful way, we introduce quality-weighted data density maps. In combination with the geological 3D
Modeling Time-Dependent Association in Longitudinal Data: A Lag as Moderator Approach
ERIC Educational Resources Information Center
Selig, James P.; Preacher, Kristopher J.; Little, Todd D.
2012-01-01
We describe a straightforward, yet novel, approach to examine time-dependent association between variables. The approach relies on a measurement-lag research design in conjunction with statistical interaction models. We base arguments in favor of this approach on the potential for better understanding the associations between variables by…
NASA Technical Reports Server (NTRS)
Hubbard, R.
1975-01-01
The radially streaming particle model for broad quasar and Seyfert galaxy emission features is modified to include sources of time dependence. The results seem to correlate with reported observations of multiple components, variability, and transient features in the wings of Seyfert and quasi-stellar emission lines.
Modeling Time-Dependent Association in Longitudinal Data: A Lag as Moderator Approach
ERIC Educational Resources Information Center
Selig, James P.; Preacher, Kristopher J.; Little, Todd D.
2012-01-01
We describe a straightforward, yet novel, approach to examine time-dependent association between variables. The approach relies on a measurement-lag research design in conjunction with statistical interaction models. We base arguments in favor of this approach on the potential for better understanding the associations between variables by…
Geometric and colour data fusion for outdoor 3D models.
Merchán, Pilar; Adán, Antonio; Salamanca, Santiago; Domínguez, Vicente; Chacón, Ricardo
2012-01-01
This paper deals with the generation of accurate, dense and coloured 3D models of outdoor scenarios from scanners. This is a challenging research field in which several problems still remain unsolved. In particular, the process of 3D model creation in outdoor scenes may be inefficient if the scene is digitalized under unsuitable technical (specific scanner on-board camera) and environmental (rain, dampness, changing illumination) conditions. We address our research towards the integration of images and range data to produce photorealistic models. Our proposal is based on decoupling the colour integration and geometry reconstruction stages, making them independent and controlled processes. This issue is approached from two different viewpoints. On the one hand, given a complete model (geometry plus texture), we propose a method to modify the original texture provided by the scanner on-board camera with the colour information extracted from external images taken at given moments and under specific environmental conditions. On the other hand, we propose an algorithm to directly assign external images onto the complete geometric model, thus avoiding tedious on-line calibration processes. We present the work conducted on two large Roman archaeological sites dating from the first century A.D., namely, the Theatre of Segobriga and the Fori Porticus of Emerita Augusta, both in Spain. The results obtained demonstrate that our approach could be useful in the digitalization and 3D modelling fields.
Geometric and Colour Data Fusion for Outdoor 3D Models
Merchán, Pilar; Adán, Antonio; Salamanca, Santiago; Domínguez, Vicente; Chacón, Ricardo
2012-01-01
This paper deals with the generation of accurate, dense and coloured 3D models of outdoor scenarios from scanners. This is a challenging research field in which several problems still remain unsolved. In particular, the process of 3D model creation in outdoor scenes may be inefficient if the scene is digitalized under unsuitable technical (specific scanner on-board camera) and environmental (rain, dampness, changing illumination) conditions. We address our research towards the integration of images and range data to produce photorealistic models. Our proposal is based on decoupling the colour integration and geometry reconstruction stages, making them independent and controlled processes. This issue is approached from two different viewpoints. On the one hand, given a complete model (geometry plus texture), we propose a method to modify the original texture provided by the scanner on-board camera with the colour information extracted from external images taken at given moments and under specific environmental conditions. On the other hand, we propose an algorithm to directly assign external images onto the complete geometric model, thus avoiding tedious on-line calibration processes. We present the work conducted on two large Roman archaeological sites dating from the first century A.D., namely, the Theatre of Segobriga and the Fori Porticus of Emerita Augusta, both in Spain. The results obtained demonstrate that our approach could be useful in the digitalization and 3D modelling fields. PMID:22969327
A method for building 3D models of barchan dunes
NASA Astrophysics Data System (ADS)
Nai, Yang; Li-lan, Su; Lin, Wan; Jie, Yang; Shi-yi, Chen; Wei-lu, Hu
2016-01-01
The distributions of barchan dunes are usually represented by digital terrain models (DTMs) overlaid with digital orthophoto maps. Given that most regions with barchan dues have low relief, a 3D map obtained from a DTM may ineffectively show the stereoscopic shape of each dune. The method of building 3D models of barchan dunes using existing modeling software seldom considers the geographical environment. As a result, barchan dune models are often inconsistent with actual DTMs and incompletely express the morphological characteristics of dunes. Manual construction of barchan dune models is also costly and time consuming. Considering these problems, the morphological characteristics of barchan dunes and the mathematical relationships between the morphological parameters of the dunes, such as length, height, and width, are analyzed in this study. The methods of extracting the morphological feature points of barchan dunes, calculating their morphological parameters and building dune outlines and skeleton lines based on the medial axes, are also presented. The dune outlines, skeleton lines, and part of the medial axes of dunes are used to construct a constrained triangulated irregular network. C# and ArcEngine are employed to build 3D models of barchan dunes automatically. Experimental results of a study conducted in Tengger Desert show that the method can be used to approximate the morphological characteristics of barchan dunes and is less time consuming than manual methods.
Towards a 3d Spatial Urban Energy Modelling Approach
NASA Astrophysics Data System (ADS)
Bahu, J.-M.; Koch, A.; Kremers, E.; Murshed, S. M.
2013-09-01
Today's needs to reduce the environmental impact of energy use impose dramatic changes for energy infrastructure and existing demand patterns (e.g. buildings) corresponding to their specific context. In addition, future energy systems are expected to integrate a considerable share of fluctuating power sources and equally a high share of distributed generation of electricity. Energy system models capable of describing such future systems and allowing the simulation of the impact of these developments thus require a spatial representation in order to reflect the local context and the boundary conditions. This paper describes two recent research approaches developed at EIFER in the fields of (a) geo-localised simulation of heat energy demand in cities based on 3D morphological data and (b) spatially explicit Agent-Based Models (ABM) for the simulation of smart grids. 3D city models were used to assess solar potential and heat energy demand of residential buildings which enable cities to target the building refurbishment potentials. Distributed energy systems require innovative modelling techniques where individual components are represented and can interact. With this approach, several smart grid demonstrators were simulated, where heterogeneous models are spatially represented. Coupling 3D geodata with energy system ABMs holds different advantages for both approaches. On one hand, energy system models can be enhanced with high resolution data from 3D city models and their semantic relations. Furthermore, they allow for spatial analysis and visualisation of the results, with emphasis on spatially and structurally correlations among the different layers (e.g. infrastructure, buildings, administrative zones) to provide an integrated approach. On the other hand, 3D models can benefit from more detailed system description of energy infrastructure, representing dynamic phenomena and high resolution models for energy use at component level. The proposed modelling strategies
Parallel tempering and 3D spin glass models
NASA Astrophysics Data System (ADS)
Papakonstantinou, T.; Malakis, A.
2014-03-01
We review parallel tempering schemes and examine their main ingredients for accuracy and efficiency. We discuss two selection methods of temperatures and some alternatives for the exchange of replicas, including all-pair exchange methods. We measure specific heat errors and round-trip efficiency using the two-dimensional (2D) Ising model, and also test the efficiency for the ground state production in 3D spin glass models. We find that the optimization of the GS problem is highly influenced by the choice of the temperature range of the PT process. Finally, we present numerical evidence concerning the universality aspects of an anisotropic case of the 3D spin-glass model.
3-D model-based tracking for UAV indoor localization.
Teulière, Céline; Marchand, Eric; Eck, Laurent
2015-05-01
This paper proposes a novel model-based tracking approach for 3-D localization. One main difficulty of standard model-based approach lies in the presence of low-level ambiguities between different edges. In this paper, given a 3-D model of the edges of the environment, we derive a multiple hypotheses tracker which retrieves the potential poses of the camera from the observations in the image. We also show how these candidate poses can be integrated into a particle filtering framework to guide the particle set toward the peaks of the distribution. Motivated by the UAV indoor localization problem where GPS signal is not available, we validate the algorithm on real image sequences from UAV flights.
3D Multispectral Light Propagation Model For Subcutaneous Veins Imaging
Paquit, Vincent C; Price, Jeffery R; Meriaudeau, Fabrice; Tobin Jr, Kenneth William
2008-01-01
In this paper, we describe a new 3D light propagation model aimed at understanding the effects of various physiological properties on subcutaneous vein imaging. In particular, we build upon the well known MCML (Monte Carlo Multi Layer) code and present a tissue model that improves upon the current state-of-the-art by: incorporating physiological variation, such as melanin concentration, fat content, and layer thickness; including veins of varying depth and diameter; using curved surfaces from real arm shapes; and modeling the vessel wall interface. We describe our model, present results from the Monte Carlo modeling, and compare these results with those obtained with other Monte Carlo methods.
Automatic 3D virtual scenes modeling for multisensors simulation
NASA Astrophysics Data System (ADS)
Latger, Jean; Le Goff, Alain; Cathala, Thierry; Larive, Mathieu
2006-05-01
SEDRIS that stands for Synthetic Environment Data Representation and Interchange Specification is a DoD/DMSO initiative in order to federate and make interoperable 3D mocks up in the frame of virtual reality and simulation. This paper shows an original application of SEDRIS concept for research physical multi sensors simulation, when SEDRIS is more classically known for training simulation. CHORALE (simulated Optronic Acoustic Radar battlefield) is used by the French DGA/DCE (Directorate for Test and Evaluation of the French Ministry of Defense) to perform multi-sensors simulations. CHORALE enables the user to create virtual and realistic multi spectral 3D scenes, and generate the physical signal received by a sensor, typically an IR sensor. In the scope of this CHORALE workshop, French DGA has decided to introduce a SEDRIS based new 3D terrain modeling tool that enables to create automatically 3D databases, directly usable by the physical sensor simulation CHORALE renderers. This AGETIM tool turns geographical source data (including GIS facilities) into meshed geometry enhanced with the sensor physical extensions, fitted to the ray tracing rendering of CHORALE, both for the infrared, electromagnetic and acoustic spectrum. The basic idea is to enhance directly the 2D source level with the physical data, rather than enhancing the 3D meshed level, which is more efficient (rapid database generation) and more reliable (can be generated many times, changing some parameters only). The paper concludes with the last current evolution of AGETIM in the scope mission rehearsal for urban war using sensors. This evolution includes indoor modeling for automatic generation of inner parts of buildings.
Engineering cancer microenvironments for in vitro 3-D tumor models
Asghar, Waseem; El Assal, Rami; Shafiee, Hadi; Pitteri, Sharon; Paulmurugan, Ramasamy; Demirci, Utkan
2017-01-01
The natural microenvironment of tumors is composed of extracellular matrix (ECM), blood vasculature, and supporting stromal cells. The physical characteristics of ECM as well as the cellular components play a vital role in controlling cancer cell proliferation, apoptosis, metabolism, and differentiation. To mimic the tumor microenvironment outside the human body for drug testing, two-dimensional (2-D) and murine tumor models are routinely used. Although these conventional approaches are employed in preclinical studies, they still present challenges. For example, murine tumor models are expensive and difficult to adopt for routine drug screening. On the other hand, 2-D in vitro models are simple to perform, but they do not recapitulate natural tumor microenvironment, because they do not capture important three-dimensional (3-D) cell–cell, cell–matrix signaling pathways, and multi-cellular heterogeneous components of the tumor microenvironment such as stromal and immune cells. The three-dimensional (3-D) in vitro tumor models aim to closely mimic cancer microenvironments and have emerged as an alternative to routinely used methods for drug screening. Herein, we review recent advances in 3-D tumor model generation and highlight directions for future applications in drug testing. PMID:28458612
Generation and use of human 3D-CAD models
NASA Astrophysics Data System (ADS)
Grotepass, Juergen; Speyer, Hartmut; Kaiser, Ralf
2002-05-01
Individualized Products are one of the ten mega trends of the 21st Century with human modeling as the key issue for tomorrow's design and product development. The use of human modeling software for computer based ergonomic simulations within the production process increases quality while reducing costs by 30- 50 percent and shortening production time. This presentation focuses on the use of human 3D-CAD models for both, the ergonomic design of working environments and made to measure garment production. Today, the entire production chain can be designed, individualized models generated and analyzed in 3D computer environments. Anthropometric design for ergonomics is matched to human needs, thus preserving health. Ergonomic simulation includes topics as human vision, reachability, kinematics, force and comfort analysis and international design capabilities. In German more than 17 billions of Mark are moved to other industries, because clothes do not fit. Individual clothing tailored to the customer's preference means surplus value, pleasure and perfect fit. The body scanning technology is the key to generation and use of human 3D-CAD models for both, the ergonomic design of working environments and made to measure garment production.
Two-equation turbulence modeling for 3-D hypersonic flows
NASA Technical Reports Server (NTRS)
Bardina, J. E.; Coakley, T. J.; Marvin, J. G.
1992-01-01
An investigation to verify, incorporate and develop two-equation turbulence models for three-dimensional high speed flows is presented. The current design effort of hypersonic vehicles has led to an intensive study of turbulence models for compressible hypersonic flows. This research complements an extensive review of experimental data and the current development of 2D turbulence models. The review of experimental data on 2D and 3D flows includes complex hypersonic flows with pressure profiles, skin friction, wall heat transfer, and turbulence statistics data. In a parallel effort, turbulence models for high speed flows have been tested against flat plate boundary layers, and are being tested against the 2D database. In the present paper, we present the results of 3D Navier-Stokes numerical simulations with an improved k-omega two-equation turbulence model against experimental data and empirical correlations of an adiabatic flat plate boundary layer, a cold wall flat plate boundary layer, and a 3D database flow, the interaction of an oblique shock wave and a thick turbulent boundary layer with a free stream Mach number = 8.18 and Reynolds number = 5 x 10 to the 6th.
Method for modeling post-mortem biometric 3D fingerprints
NASA Astrophysics Data System (ADS)
Rajeev, Srijith; Shreyas, Kamath K. M.; Agaian, Sos S.
2016-05-01
Despite the advancements of fingerprint recognition in 2-D and 3-D domain, authenticating deformed/post-mortem fingerprints continue to be an important challenge. Prior cleansing and reconditioning of the deceased finger is required before acquisition of the fingerprint. The victim's finger needs to be precisely and carefully operated by a medium to record the fingerprint impression. This process may damage the structure of the finger, which subsequently leads to higher false rejection rates. This paper proposes a non-invasive method to perform 3-D deformed/post-mortem finger modeling, which produces a 2-D rolled equivalent fingerprint for automated verification. The presented novel modeling method involves masking, filtering, and unrolling. Computer simulations were conducted on finger models with different depth variations obtained from Flashscan3D LLC. Results illustrate that the modeling scheme provides a viable 2-D fingerprint of deformed models for automated verification. The quality and adaptability of the obtained unrolled 2-D fingerprints were analyzed using NIST fingerprint software. Eventually, the presented method could be extended to other biometric traits such as palm, foot, tongue etc. for security and administrative applications.
Interplay between chaotic and regular motion in a time-dependent barred galaxy model
NASA Astrophysics Data System (ADS)
Manos, T.; Bountis, T.; Skokos, Ch
2013-06-01
We study the distinction and quantification of chaotic and regular motion in a time-dependent Hamiltonian barred galaxy model. Recently, a strong correlation was found between the strength of the bar and the presence of chaotic motion in this system, as models with relatively strong bars were shown to exhibit stronger chaotic behavior compared to those having a weaker bar component. Here, we attempt to further explore this connection by studying the interplay between chaotic and regular behavior of star orbits when the parameters of the model evolve in time. This happens for example when one introduces linear time dependence in the mass parameters of the model to mimic, in some general sense, the effect of self-consistent interactions of the actual N-body problem. We thus observe, in this simple time-dependent model also, that the increase of the bar’s mass leads to an increase of the system’s chaoticity. We propose a new way of using the generalized alignment index (GALI) method as a reliable criterion to estimate the relative fraction of chaotic versus regular orbits in such time-dependent potentials, which proves to be much more efficient than the computation of Lyapunov exponents. In particular, GALI is able to capture subtle changes in the nature of an orbit (or ensemble of orbits) even for relatively small time intervals, which makes it ideal for detecting dynamical transitions in time-dependent systems. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Lyapunov analysis: from dynamical systems theory to applications’.
3D cartographic modeling of the Alpine arc
NASA Astrophysics Data System (ADS)
Vouillamoz, Naomi; Sue, Christian; Champagnac, Jean-Daniel; Calcagno, Philippe
2012-12-01
We built a 3D cartography of the Alpine arc, a highly non-cylindrical mountain belt, using the 3D GeoModeller of the BRGM (French geological survey). The model allows to handle the large-scale 3D structure of seventeen major crustal units of the belt (from the lower crust to the sedimentary cover nappes), and two main discontinuities (the Insubric Line and the Crustal Penninic Front). It provides a unique document to better understand their structural relationships and to produce new sections. The study area comprises the western Alpine arc, from the Jura to the Northwest, up to the Bergell granite intrusion and the Lepontine Dome to the East, and is limited to the South by the Ligurian basin. The model is limited vertically 10 km above sea level at the top, and the moho interface at the bottom. We discarded the structural relationships between the Alps sensus stricto and the surrounding geodynamic systems such as the Rhine graben or the connection with the Apennines. The 3D-model is based on the global integration of various data such as the DEM of the Alps, the moho isobaths, the simplified geological and tectonic maps of the belt, the crustal cross-sections ECORS-CROP and NFP-20, and complementary cross-sections specifically built to precise local complexities. The database has first been integrated in a GIS-project to prepare their implementation in the GeoModeller, by homogenizing the different spatial referencing systems. The global model is finally interpolated from all these data, using the potential field method. The final document is a new tri-dimensional cartography that would be used as input for further alpine studies.
3D modeling of dual-gate FinFET
2012-01-01
The tendency to have better control of the flow of electrons in a channel of field-effect transistors (FETs) did lead to the design of two gates in junction field-effect transistors, field plates in a variety of metal semiconductor field-effect transistors and high electron mobility transistors, and finally a gate wrapping around three sides of a narrow fin-shaped channel in a FinFET. With the enhanced control, performance trends of all FETs are still challenged by carrier mobility dependence on the strengths of the electrical field along the channel. However, in cases when the ratio of FinFET volume to its surface dramatically decreases, one should carefully consider the surface boundary conditions of the device. Moreover, the inherent non-planar nature of a FinFET demands 3D modeling for accurate analysis of the device performance. Using the Silvaco modeling tool with quantization effects, we modeled a physical FinFET described in the work of Hisamoto et al. (IEEE Tran. Elec. Devices 47:12, 2000) in 3D. We compared it with a 2D model of the same device. We demonstrated that 3D modeling produces more accurate results. As 3D modeling results came close to experimental measurements, we made the next step of the study by designing a dual-gate FinFET biased at Vg1 >Vg2. It is shown that the dual-gate FinFET carries higher transconductance than the single-gate device. PMID:23148493
Geometric and Textural Blending for 3D Model Stylization.
Huang, YiJheng; Lin, Wen-Chieh; Yeh, I-Cheng; Lee, Tong-Yee
2017-01-25
Stylizing a 3D model with characteristic shapes or appearances is common in product design, particularly in the design of 3D model merchandise, such as souvenirs, toys, furniture, and stylized items. A model stylization approach is proposed in this study. The approach combines base and style models while preserving user-specified shape features of the base model and the attractive features of the style model with limited assistance from a user. The two models are first combined at the topological level. A tree-growing technique is utilized to search for all possible combinations of the two models. Second, the models are combined at textural and geometric levels by employing a morphing technique. Results show that the proposed approach generates various appealing models and allows users to control the diversity of the output models and adjust the blending degree between the base and style models. The results of this work are also experimentally compared with those of a recent work through a user study. The comparison indicates that our results are more appealing, feature-preserving, and reasonable than those of the compared previous study. The proposed system allows product designers to easily explore design possibilities and assists novice users in creating their own stylized models.
3D-DART: a DNA structure modelling server
van Dijk, Marc; Bonvin, Alexandre M. J. J.
2009-01-01
There is a growing interest in structural studies of DNA by both experimental and computational approaches. Often, 3D-structural models of DNA are required, for instance, to serve as templates for homology modeling, as starting structures for macro-molecular docking or as scaffold for NMR structure calculations. The conformational adaptability of DNA when binding to a protein is often an important factor and at the same time a limitation in such studies. As a response to the demand for 3D-structural models reflecting the intrinsic plasticity of DNA we present the 3D-DART server (3DNA-Driven DNA Analysis and Rebuilding Tool). The server provides an easy interface to a powerful collection of tools for the generation of DNA-structural models in custom conformations. The computational engine beyond the server makes use of the 3DNA software suite together with a collection of home-written python scripts. The server is freely available at http://haddock.chem.uu.nl/dna without any login requirement. PMID:19417072
CityGML - Interoperable semantic 3D city models
NASA Astrophysics Data System (ADS)
Gröger, Gerhard; Plümer, Lutz
2012-07-01
CityGML is the international standard of the Open Geospatial Consortium (OGC) for the representation and exchange of 3D city models. It defines the three-dimensional geometry, topology, semantics and appearance of the most relevant topographic objects in urban or regional contexts. These definitions are provided in different, well-defined Levels-of-Detail (multiresolution model). The focus of CityGML is on the semantical aspects of 3D city models, its structures, taxonomies and aggregations, allowing users to employ virtual 3D city models for advanced analysis and visualization tasks in a variety of application domains such as urban planning, indoor/outdoor pedestrian navigation, environmental simulations, cultural heritage, or facility management. This is in contrast to purely geometrical/graphical models such as KML, VRML, or X3D, which do not provide sufficient semantics. CityGML is based on the Geography Markup Language (GML), which provides a standardized geometry model. Due to this model and its well-defined semantics and structures, CityGML facilitates interoperable data exchange in the context of geo web services and spatial data infrastructures. Since its standardization in 2008, CityGML has become used on a worldwide scale: tools from notable companies in the geospatial field provide CityGML interfaces. Many applications and projects use this standard. CityGML is also having a strong impact on science: numerous approaches use CityGML, particularly its semantics, for disaster management, emergency responses, or energy-related applications as well as for visualizations, or they contribute to CityGML, improving its consistency and validity, or use CityGML, particularly its different Levels-of-Detail, as a source or target for generalizations. This paper gives an overview of CityGML, its underlying concepts, its Levels-of-Detail, how to extend it, its applications, its likely future development, and the role it plays in scientific research. Furthermore, its
Critical exponents for the 3D Ising model
Gupta, R.; Tamayo, P. |
1996-03-01
The authors present a status report on the ongoing analysis of the 3D Ising model with nearest-neighbor interactions using the Monte Carlo Renormalization Group (MCRG) and finite size scaling (FSS) methods on 64{sup 3}, 128{sup 3}, and 256{sup 3} simple cubic lattices. Their MCRG estimates are K{sup c}{sub nn} = 0.221655(1)(1) and {nu} = 0.625(1). The FSS results for K{sup c} are consistent with those from MCRG but the value of {nu} is not. Their best estimate {eta} = 0.025(6) covers the spread in the MCRG and FSS values. A surprise of their calculation is the estimate {omega} {approx} 0.7 for the correction-to-scaling exponent. The authors also present results for the renormalized coupling g{sub R} along the MCRG flow and argue that the data supports the validity of hyperscaling for the 3D Ising model.
The 3D model control of image processing
NASA Technical Reports Server (NTRS)
Nguyen, An H.; Stark, Lawrence
1989-01-01
Telerobotics studies remote control of distant robots by a human operator using supervisory or direct control. Even if the robot manipulators has vision or other senses, problems arise involving control, communications, and delay. The communication delays that may be expected with telerobots working in space stations while being controlled from an Earth lab have led to a number of experiments attempting to circumvent the problem. This delay in communication is a main motivating factor in moving from well understood instantaneous hands-on manual control to less well understood supervisory control; the ultimate step would be the realization of a fully autonomous robot. The 3-D model control plays a crucial role in resolving many conflicting image processing problems that are inherent in resolving in the bottom-up approach of most current machine vision processes. The 3-D model control approach is also capable of providing the necessary visual feedback information for both the control algorithms and for the human operator.
A method for diagnosing time dependent faults using model-based reasoning systems
NASA Technical Reports Server (NTRS)
Goodrich, Charles H.
1995-01-01
This paper explores techniques to apply model-based reasoning to equipment and systems which exhibit dynamic behavior (that which changes as a function of time). The model-based system of interest is KATE-C (Knowledge based Autonomous Test Engineer) which is a C++ based system designed to perform monitoring and diagnosis of Space Shuttle electro-mechanical systems. Methods of model-based monitoring and diagnosis are well known and have been thoroughly explored by others. A short example is given which illustrates the principle of model-based reasoning and reveals some limitations of static, non-time-dependent simulation. This example is then extended to demonstrate representation of time-dependent behavior and testing of fault hypotheses in that environment.
Modeling 3D faces from samplings via compressive sensing
NASA Astrophysics Data System (ADS)
Sun, Qi; Tang, Yanlong; Hu, Ping
2013-07-01
3D data is easier to acquire for family entertainment purpose today because of the mass-production, cheapness and portability of domestic RGBD sensors, e.g., Microsoft Kinect. However, the accuracy of facial modeling is affected by the roughness and instability of the raw input data from such sensors. To overcome this problem, we introduce compressive sensing (CS) method to build a novel 3D super-resolution scheme to reconstruct high-resolution facial models from rough samples captured by Kinect. Unlike the simple frame fusion super-resolution method, this approach aims to acquire compressed samples for storage before a high-resolution image is produced. In this scheme, depth frames are firstly captured and then each of them is measured into compressed samples using sparse coding. Next, the samples are fused to produce an optimal one and finally a high-resolution image is recovered from the fused sample. This framework is able to recover 3D facial model of a given user from compressed simples and this can reducing storage space as well as measurement cost in future devices e.g., single-pixel depth cameras. Hence, this work can potentially be applied into future applications, such as access control system using face recognition, and smart phones with depth cameras, which need high resolution and little measure time.
3D thermal modelling of the Upper Rhine Graben
NASA Astrophysics Data System (ADS)
Freymark, Jessica; Sippel, Judith; Scheck-Wenderoth, Magdalena; Bär, Kristian; Stiller, Manfred; Fritsche, Johann-Gerhard; Kracht, Matthias
2017-04-01
The Upper Rhine Graben (URG) is a promising target for deep geothermal energy production. As part of the EU-funded project "IMAGE" (Integrated Methods for Advanced Geothermal Exploration, grant agreement no. 608553), we aim to understand the processes that control the temperature distribution in the subsurface of the URG by using numerical simulations. Reservoir-scale numerical models are often used to predict the hydrothermal conditions and to reduce the risk of drilling non-productive geothermal wells. One major problem related to such reservoir-scale models is setting appropriate boundary conditions that define, for instance, how much heat enters the reservoir from greater depths. To overcome this problem, we combine lithospheric-scale 3D structural and thermal modelling with higher resolved hydrothermal models of the sedimentary basin fill in a workflow of successive modelling steps. After model parameterization with thermal rock properties we solve the steady-state conductive heat equation first to calculate the 3D conductive thermal field and to understand the first-order controlling factors of the regional temperature distribution. In a second step we took into account the fluid flow due to permeability variations in the porous media and the influence of major faults, which locally change the temperature distribution. These numerical simulations of coupled heat and fluid transport were performed on smaller and higher resolved models of the basin fill for which the conductive thermal model provide the thermal boundary conditions. We present the methodological workflow, the developed 3D structural and thermal models, and assess how heat transport mechanisms in response to lithological and structural features on different scales control subsurface temperatures.
3D modelling of the Black Sea ecosystem
NASA Astrophysics Data System (ADS)
Capet, A.; Gregoire, M.; Beckers, J.-M.; Joassin, P.; Naithani, J.; Soetart, K.
2009-04-01
A coupled physical-biogeochemical model has been developed to simulate the ecosystem of the Black Sea at the end of the 80's when eutrophication and invasion by gelatinous organisms seriously affected the stability and dynamics of the system. The biogeochemical model describes the cycle of carbon, nitrogen, silicate, oxygen and phosphorus through the foodweb from bacteria to gelatinous carnivores and explicitly represents processes in the anoxic layer down to the bottom. For calibration and analyses purposes, the coupled model has first been run in 1D at several places in the Black Sea. The biogeochemical model involves some hundred parameters which have been first calibrated by hand using published values. Then, an identifiability analysis has been performed in order to determine a subset of 15 identifiable parameters. An automatic calibration subroutine has been used to fine tune these parameters. In 1D, the model solution exhibits a complex dynamics with several years of transient adjustment. This complexity is imparted by the explicit modelling of top predators. The model has been calibrated and validated using a large set of data available in the Black Sea TU Ocean Base. The calibrated biogeochemical model is implemented in a 3D hydrodynamical model of the Black Sea. Results of these 3D simulations will be presented and compared with maps of in-situ data reconstructed from available data base using the software DIVA (Data Interpolation and Variational analysis).
West Flank Coso, CA FORGE 3D geologic model
Doug Blankenship
2016-03-01
This is an x,y,z file of the West Flank FORGE 3D geologic model. Model created in Earthvision by Dynamic Graphic Inc. The model was constructed with a grid spacing of 100 m. Geologic surfaces were extrapolated from the input data using a minimum tension gridding algorithm. The data file is tabular data in a text file, with lithology data associated with X,Y,Z grid points. All the relevant information is in the file header (the spatial reference, the projection etc.) In addition all the fields in the data file are identified in the header.
Periodic time-dependent parameters improving forecasting abilities of biological ocean models
NASA Astrophysics Data System (ADS)
Mattern, Jann Paul; Fennel, Katja; Dowd, Michael
2014-10-01
Using two emulator-based procedures, we estimate time-dependent values for two key plankton parameters in a three-dimensional biogeochemical (BGC) ocean model. The estimation is based on a 4 year time series of daily surface satellite chlorophyll observations. The estimated parameters display an annual periodicity that can be explained by the succession of plankton groups in the study region. Model simulations using these parameters show improved fit to observations and better forecasting abilities compared to simulations with constant optimal parameters; the newly introduced sequential parameter estimation procedure creates the strongest improvement. The inclusion of time-dependent parameters represents a simple way to improve the predictive skill of BGC models and their representation of plankton dynamics.
Effective 3-D surface modeling for geographic information systems
NASA Astrophysics Data System (ADS)
Yüksek, K.; Alparslan, M.; Mendi, E.
2016-01-01
In this work, we propose a dynamic, flexible and interactive urban digital terrain platform with spatial data and query processing capabilities of geographic information systems, multimedia database functionality and graphical modeling infrastructure. A new data element, called Geo-Node, which stores image, spatial data and 3-D CAD objects is developed using an efficient data structure. The system effectively handles data transfer of Geo-Nodes between main memory and secondary storage with an optimized directional replacement policy (DRP) based buffer management scheme. Polyhedron structures are used in digital surface modeling and smoothing process is performed by interpolation. The experimental results show that our framework achieves high performance and works effectively with urban scenes independent from the amount of spatial data and image size. The proposed platform may contribute to the development of various applications such as Web GIS systems based on 3-D graphics standards (e.g., X3-D and VRML) and services which integrate multi-dimensional spatial information and satellite/aerial imagery.
Northern California Seismic Attenuation: 3-D Qp and Qs models
NASA Astrophysics Data System (ADS)
Eberhart-Phillips, D. M.
2015-12-01
The northern California crust exhibits a wide range of rock types and deformation processes which produce pronounced heterogeneity in regional attenuation. Using local earthquakes, 3-D Qp and Qs crustal models have been obtained for this region which includes the San Andreas fault system, the Central Valley, the Sierra Nevada batholith, and the Mendocino subduction volcanic system. Path attenuation t* values were determined from P and S spectra of 959 spatially distributed earthquakes, magnitude 2.5-6.0 from 2005-2014, using 1254 stations from NCEDC networks and IRIS Mendocino and Sierra Nevada temporary arrays. The t* data were used in Q inversions, using existing hypocenters and 3-D velocity models, with basic 10-km node spacing. The uneven data coverage was accounted for with linking of nodes into larger areas in order to provide useful Q images across the 3-D volume. The results at shallow depth (< 2 km) show very low Q in the Sacramento Delta, the Eureka area, and parts of the Bay Area. In the brittle crust, fault zones that have high seismicity exhibit low Q. In the lower crust, low Q is observed along fault zones that have large cumulative displacement and have experienced grain size reduction. Underlying active volcanic areas, low Q features are apparent below 20-km depth. Moderately high Q is associated with igneous rocks of the Sierra Nevada and Salinian block, while the Franciscan subduction complex shows moderately low Q. The most prominent high Q feature is related to the Great Valley Ophiolite.
3D-printer visualization of neuron models
McDougal, Robert A.; Shepherd, Gordon M.
2015-01-01
Neurons come in a wide variety of shapes and sizes. In a quest to understand this neuronal diversity, researchers have three-dimensionally traced tens of thousands of neurons; many of these tracings are freely available through online repositories like NeuroMorpho.Org and ModelDB. Tracings can be visualized on the computer screen, used for statistical analysis of the properties of different cell types, used to simulate neuronal behavior, and more. We introduce the use of 3D printing as a technique for visualizing traced morphologies. Our method for generating printable versions of a cell or group of cells is to expand dendrite and axon diameters and then to transform the tracing into a 3D object with a neuronal surface generating algorithm like Constructive Tessellated Neuronal Geometry (CTNG). We show that 3D printed cells can be readily examined, manipulated, and compared with other neurons to gain insight into both the biology and the reconstruction process. We share our printable models in a new database, 3DModelDB, and encourage others to do the same with cells that they generate using our code or other methods. To provide additional context, 3DModelDB provides a simulatable version of each cell, links to papers that use or describe it, and links to associated entries in other databases. PMID:26175684
3D-printer visualization of neuron models.
McDougal, Robert A; Shepherd, Gordon M
2015-01-01
Neurons come in a wide variety of shapes and sizes. In a quest to understand this neuronal diversity, researchers have three-dimensionally traced tens of thousands of neurons; many of these tracings are freely available through online repositories like NeuroMorpho.Org and ModelDB. Tracings can be visualized on the computer screen, used for statistical analysis of the properties of different cell types, used to simulate neuronal behavior, and more. We introduce the use of 3D printing as a technique for visualizing traced morphologies. Our method for generating printable versions of a cell or group of cells is to expand dendrite and axon diameters and then to transform the tracing into a 3D object with a neuronal surface generating algorithm like Constructive Tessellated Neuronal Geometry (CTNG). We show that 3D printed cells can be readily examined, manipulated, and compared with other neurons to gain insight into both the biology and the reconstruction process. We share our printable models in a new database, 3DModelDB, and encourage others to do the same with cells that they generate using our code or other methods. To provide additional context, 3DModelDB provides a simulatable version of each cell, links to papers that use or describe it, and links to associated entries in other databases.
Effective 3-D surface modeling for geographic information systems
NASA Astrophysics Data System (ADS)
Yüksek, K.; Alparslan, M.; Mendi, E.
2013-11-01
In this work, we propose a dynamic, flexible and interactive urban digital terrain platform (DTP) with spatial data and query processing capabilities of Geographic Information Systems (GIS), multimedia database functionality and graphical modeling infrastructure. A new data element, called Geo-Node, which stores image, spatial data and 3-D CAD objects is developed using an efficient data structure. The system effectively handles data transfer of Geo-Nodes between main memory and secondary storage with an optimized Directional Replacement Policy (DRP) based buffer management scheme. Polyhedron structures are used in Digital Surface Modeling (DSM) and smoothing process is performed by interpolation. The experimental results show that our framework achieves high performance and works effectively with urban scenes independent from the amount of spatial data and image size. The proposed platform may contribute to the development of various applications such as Web GIS systems based on 3-D graphics standards (e.g. X3-D and VRML) and services which integrate multi-dimensional spatial information and satellite/aerial imagery.
Right approach to 3D modeling using CAD tools
NASA Astrophysics Data System (ADS)
Baddam, Mounica Reddy
The thesis provides a step-by-step methodology to enable an instructor dealing with CAD tools to optimally guide his/her students through an understandable 3D modeling approach which will not only enhance their knowledge about the tool's usage but also enable them to achieve their desired result in comparatively lesser time. In the known practical field, there is particularly very little information available to apply CAD skills to formal beginners' training sessions. Additionally, advent of new software in 3D domain cumulates updating into a more difficult task. Keeping up to the industry's advanced requirements emphasizes the importance of more skilled hands in the field of CAD development, rather than just prioritizing manufacturing in terms of complex software features. The thesis analyses different 3D modeling approaches specified to the varieties of CAD tools currently available in the market. Utilizing performance-time databases, learning curves have been generated to measure their performance time, feature count etc. Based on the results, improvement parameters have also been provided for (Asperl, 2005).
Individual patient oesophageal cancer 3D models for tailored treatment
Saunders, John H.; Onion, David; Collier, Pamela; Dorrington, Matthew S.; Argent, Richard H.; Clarke, Philip A.; Reece-Smith, Alex M.; Parsons, Simon L.; Grabowska, Anna M.
2017-01-01
Background A model to predict chemotherapy response would provide a marked clinical benefit, enabling tailored treatment of oesophageal cancer, where less than half of patients respond to the routinely administered chemotherapy. Methods Cancer cells were established from tumour biopsies taken from individual patients about to undergo neoadjuvant chemotherapy. A 3D-tumour growth assay (3D-TGA) was developed, in which cancer cells were grown with or without supporting mesenchymal cells, then subjected to chemo-sensitivity testing using the standard chemotherapy administered in clinic, and a novel emerging HDAC inhibitor, Panobinostat. RESULTS Individual patients cancer cells could be expanded and screened within a clinically applicable timescale of 3 weeks. Incorporating mesenchymal support within the 3D-TGA significantly enhanced both the growth and drug resistance profiles of the patients cancer cells. The ex vivo drug response in the presence, but not absence, of mesenchymal cells accurately reflected clinical chemo-sensitivity, as measured by tumour regression grade. Combination with Panobinostat enhanced response and proved efficacious in otherwise chemo-resistant tumours. Conclusions This novel method of establishing individual patient oesophageal cancers in the laboratory, from small endoscopic biopsies, enables clinically-relevant chemo-sensitivity testing, and reduces use of animals by providing more refined in vitro models for pre-screening of drugs. The 3D-TGA accurately predicted chemo-sensitivity in patients, and could be developed to guide tailored patient treatment. The incorporation of mesenchymal cells as the stromal cell component of the tumour micro-environment had a significant effect upon enhancing chemotherapy drug resistance in oesophageal cancer, and could prove a useful target for future drug development. PMID:27736801
Computational Challenges of 3D Radiative Transfer in Atmospheric Models
NASA Astrophysics Data System (ADS)
Jakub, Fabian; Bernhard, Mayer
2017-04-01
The computation of radiative heating and cooling rates is one of the most expensive components in todays atmospheric models. The high computational cost stems not only from the laborious integration over a wide range of the electromagnetic spectrum but also from the fact that solving the integro-differential radiative transfer equation for monochromatic light is already rather involved. This lead to the advent of numerous approximations and parameterizations to reduce the cost of the solver. One of the most prominent one is the so called independent pixel approximations (IPA) where horizontal energy transfer is neglected whatsoever and radiation may only propagate in the vertical direction (1D). Recent studies implicate that the IPA introduces significant errors in high resolution simulations and affects the evolution and development of convective systems. However, using fully 3D solvers such as for example MonteCarlo methods is not even on state of the art supercomputers feasible. The parallelization of atmospheric models is often realized by a horizontal domain decomposition, and hence, horizontal transfer of energy necessitates communication. E.g. a cloud's shadow at a low zenith angle will cast a long shadow and potentially needs to communication through a multitude of processors. Especially light in the solar spectral range may travel long distances through the atmosphere. Concerning highly parallel simulations, it is vital that 3D radiative transfer solvers put a special emphasis on parallel scalability. We will present an introduction to intricacies computing 3D radiative heating and cooling rates as well as report on the parallel performance of the TenStream solver. The TenStream is a 3D radiative transfer solver using the PETSc framework to iteratively solve a set of partial differential equation. We investigate two matrix preconditioners, (a) geometric algebraic multigrid preconditioning(MG+GAMG) and (b) block Jacobi incomplete LU (ILU) factorization. The
Modeling and Processing of Continuous 3D Elastic Wavefield Data
NASA Astrophysics Data System (ADS)
Milkereit, B.; Bohlen, T.
2001-12-01
Continuous seismic wavefields are excited by earthquake clustering, induced seismicity in reservoirs, and mining. In hydrocarbon reservoirs, for example, pore pressure changes and fluid flow (mass transfer) will cause incremental deviatoric stresses sufficient to trigger and sustain seismic activity. Here we address three aspects of seismic wavefields in three-dimensional heterogeneous media triggered by distributed sources in space and time: forward modeling, multichannel data processing, and source location imaging. A power law distribution of seismic sources (such as the Gutenberg-Richter law) is used for the modeling of viscoelastic/elastic wave propagation through a realistic earth model. 3D modeling provides new insight in the interaction of multi-source wavefields and the role of scale-dependend elastic model parameters on transmitted and reflected/back-scattered wavefields. There exists a strong correlation between the spatial properties of the compressional, shear wave and density perturbations and the lateral correlation length of the resulting reflected or transmitted seismic wavefields. Modeling is based on the implementation of 3D elastic/viscoelastic FD codes on massive parallel and/or distributed computing resources using MPI (message passing interface). For parallelization, large grid 3D earth models are decomposed into subvolume processing elements whereby each processing element is updating the wavefield within its portion of the grid. Processing of continuous seismic wavefields excited by multiple distributed sources is based on a combination of crosscorrelated or slowness-transformed array data and Kirchhoff or reverse time migration for source location or source volume imaging. The appearance of slowness in both migration and array data processing suggests the possibility of combining them into a single process. In order to place further constraints on the migration, the directivity properties of 3-component receiver arrays can be included in
Underwater 3d Modeling: Image Enhancement and Point Cloud Filtering
NASA Astrophysics Data System (ADS)
Sarakinou, I.; Papadimitriou, K.; Georgoula, O.; Patias, P.
2016-06-01
This paper examines the results of image enhancement and point cloud filtering on the visual and geometric quality of 3D models for the representation of underwater features. Specifically it evaluates the combination of effects from the manual editing of images' radiometry (captured at shallow depths) and the selection of parameters for point cloud definition and mesh building (processed in 3D modeling software). Such datasets, are usually collected by divers, handled by scientists and used for geovisualization purposes. In the presented study, have been created 3D models from three sets of images (seafloor, part of a wreck and a small boat's wreck) captured at three different depths (3.5m, 10m and 14m respectively). Four models have been created from the first dataset (seafloor) in order to evaluate the results from the application of image enhancement techniques and point cloud filtering. The main process for this preliminary study included a) the definition of parameters for the point cloud filtering and the creation of a reference model, b) the radiometric editing of images, followed by the creation of three improved models and c) the assessment of results by comparing the visual and the geometric quality of improved models versus the reference one. Finally, the selected technique is tested on two other data sets in order to examine its appropriateness for different depths (at 10m and 14m) and different objects (part of a wreck and a small boat's wreck) in the context of an ongoing research in the Laboratory of Photogrammetry and Remote Sensing.
3D Geologic Model of the San Diego Area
NASA Astrophysics Data System (ADS)
Danskin, W. R.; Cromwell, G.; Glockhoff, C.; Martin, D.
2015-12-01
Prior geologic studies of the San Diego area, including northern Baja California, Mexico, focused on site investigations, characterization of rock formations, or earthquake hazards. No comprehensive, quantitative model characterizing the three-dimensional (3D) geology of the entire area has been developed. The lack of such a model limits understanding of large-scale processes, such as development of ancient landforms, and groundwater movement and availability. To evaluate these regional processes, the United States Geological Survey (USGS) conducted a study to better understand the geologic structure of the San Diego area. A cornerstone of this study is the installation and analysis of 77 wells at 12 multiple-depth monitoring-well sites. Geologic information from these wells was combined with lithologic data from 81 oil exploration wells and municipal and private water wells, gravity and seismic interpretations, and paleontological interpretations. These data were analyzed in conjunction with geologic maps and digital elevation models to develop a 3D geologic model of the San Diego area, in particular of the San Diego embayment. Existing interpretations of regional surficial geology, faulting, and tectonic history provided the framework for this model, which was refined by independent evaluation of subsurface geology. Geologic formations were simplified into five sedimentary units (Quaternary, Plio-Pleistocene, Oligocene, Eocene and Cretaceous ages), and one basal crystalline unit (primarily Cretaceous and Jurassic). Complex fault systems are represented in the model by ten fault strands that maintain overall displacement. The 3D geologic model corroborates existing geologic concepts of the San Diego area, refines the extent of subsurface geology, and allows users to holistically evaluate subsurface structures and regional hydrogeology.
Digital 3D Borobudur - Integration of 3D surveying and modeling techniques
NASA Astrophysics Data System (ADS)
Suwardhi, D.; Menna, F.; Remondino, F.; Hanke, K.; Akmalia, R.
2015-08-01
The Borobudur temple (Indonesia) is one of the greatest Buddhist monuments in the world, now listed as an UNESCO World Heritage Site. The present state of the temple is the result of restorations after being exposed to natural disasters several times. Today there is still a growing rate of deterioration of the building stones whose causes need further researches. Monitoring programs, supported at institutional level, have been effectively executed to observe the problem. The paper presents the latest efforts to digitally document the Borobudur Temple and its surrounding area in 3D with photogrammetric techniques. UAV and terrestrial images were acquired to completely digitize the temple, produce DEM, orthoimages and maps at 1:100 and 1:1000 scale. The results of the project are now employed by the local government organizations to manage the heritage area and plan new policies for the conservation and preservation of the UNESCO site. In order to help data management and policy makers, a web-based information system of the heritage area was also built to visualize and easily access all the data and achieved 3D results.
3D flare particle model for ShipIR/NTCS
NASA Astrophysics Data System (ADS)
Ramaswamy, Srinivasan; Vaitekunas, David A.
2016-05-01
A key component in any soft-kill response to an incoming guided missile is the flare /chaff decoy used to distract or seduce the seeker homing system away from the naval platform. This paper describes a new 3D flare particle model in the naval threat countermeasure simulator (NTCS) of the NATO-standard ship signature model (ShipIR), which provides independent control over the size and radial distribution of its signature. The 3D particles of each flare sub-munition are modelled stochastically and rendered using OpenGL z-buffering, 2D projection, and alpha-blending to produce a unique and time varying signature. A sensitivity analysis on each input parameter provides the data and methods needed to synthesize a model from an IR measurement of a decoy. The new model also eliminated artifacts and deficiencies in our previous model which prevented reliable tracks from the adaptive track gate algorithm already presented by Ramaswamy and Vaitekunas (2015). A sequence of scenarios are used to test and demonstrate the new flare model during a missile engagement.
3D digital anatomy modelling - Practical or pretty?
Murgitroyd, Ellen; Madurska, Marta; Gonzalez, Jasmina; Watson, Angus
2015-06-01
With an increasing move towards digitalisation of medical records and medical teaching, such as online exams and webinars, one of the questions that persists asks 'is there a place for digital anatomy teaching and can it effectively replace the traditional teaching methods such as cadaveric dissection?' Cadaveric dissection has a number of benefits as a teaching method but it also has its limitations. Although these can be partially addressed by prosections and new more "life-like" fixatives, it does not address the lack of resources and the increasing pressure to be able to study and learn at home. This paper reviews the literature with regards to the suitability of digital models for teaching and the wider uses a 3D digital anatomy model could have, such as postgraduate teaching, patient education and surgical planning. It also looks briefly at the learning model that anatomy as art contributes. The literature has scattered examples of digital models used for teaching at both undergraduate and postgraduate level, which demonstrate a number of positive outcomes, mostly surrounding user satisfaction and convenience. 3D modelling for patient education and operation planning has less exploration, and these papers generate a number of discussion points, mostly surrounding the practicality of digital models, which can be more time consuming and require the technology to be widely available and reliable. 3D digital anatomy is a useful adjunct to teaching and its use in patient education and operation planning have interesting possibilities still to be fully explored. Copyright © 2014 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.
Modeling Extracellular Matrix Reorganization in 3D Environments
Harjanto, Dewi; Zaman, Muhammad H.
2013-01-01
Extracellular matrix (ECM) remodeling is a key physiological process that occurs in a number of contexts, including cell migration, and is especially important for cellular form and function in three-dimensional (3D) matrices. However, there have been few attempts to computationally model how cells modify their environment in a manner that accounts for both cellular properties and the architecture of the surrounding ECM. To this end, we have developed and validated a novel model to simulate matrix remodeling that explicitly defines cells in a 3D collagenous matrix. In our simulation, cells can degrade, deposit, or pull on local fibers, depending on the fiber density around each cell. The cells can also move within the 3D matrix. Different cell phenotypes can be modeled by varying key cellular parameters. Using the model we have studied how two model cancer cell lines, of differing invasiveness, modify matrices with varying fiber density in their vicinity by tracking the metric of fraction of matrix occupied by fibers. Our results quantitatively demonstrate that in low density environments, cells deposit more collagen to uniformly increase fibril fraction. On the other hand, in higher density environments, the less invasive model cell line reduced the fibril fraction as compared to the highly invasive phenotype. These results show good qualitative and quantitative agreement with existing experimental literature. Our simulation is therefore able to function as a novel platform to provide new insights into the clinically relevant and physiologically critical process of matrix remodeling by helping identify critical parameters that dictate cellular behavior in complex native-like environments. PMID:23341900
NASA Astrophysics Data System (ADS)
Norajitra, Tobias; Meinzer, Hans-Peter; Maier-Hein, Klaus H.
2015-03-01
During image segmentation, 3D Statistical Shape Models (SSM) usually conduct a limited search for target landmarks within one-dimensional search profiles perpendicular to the model surface. In addition, landmark appearance is modeled only locally based on linear profiles and weak learners, altogether leading to segmentation errors from landmark ambiguities and limited search coverage. We present a new method for 3D SSM segmentation based on 3D Random Forest Regression Voting. For each surface landmark, a Random Regression Forest is trained that learns a 3D spatial displacement function between the according reference landmark and a set of surrounding sample points, based on an infinite set of non-local randomized 3D Haar-like features. Landmark search is then conducted omni-directionally within 3D search spaces, where voxelwise forest predictions on landmark position contribute to a common voting map which reflects the overall position estimate. Segmentation experiments were conducted on a set of 45 CT volumes of the human liver, of which 40 images were randomly chosen for training and 5 for testing. Without parameter optimization, using a simple candidate selection and a single resolution approach, excellent results were achieved, while faster convergence and better concavity segmentation were observed, altogether underlining the potential of our approach in terms of increased robustness from distinct landmark detection and from better search coverage.
Local time dependence of polar mesospheric clouds and model validation with satellite data
NASA Astrophysics Data System (ADS)
Schmidt, Francie; Berger, Uwe; Lübken, Franz-Josef
2016-04-01
Polar mesospheric clouds (PMCs), also known as noctilucent clouds (NLCs), consist of water-ice cystals. They occur at high latitudes in the summer mesopause region at very low temperatures below 150 K. In this case PMCs are highly sensitive to atmospheric conditions. Therefore, PMCs are thought to be sensitive indicators of climate changes in the middle atmosphere. The ice clouds show spatial and temporal variations. We present a model that can help to understand the variability of mesospheric clouds. The model is called Mesospheric Ice Microphysics And tranSport model (MIMAS) and is a threedimensional Lagrangian transport model, which can be used on multiple dynamic fields. MIMAS is a good instrument to check observations and also to fill some gaps that are included in satellite observations, e.g., the local time dependence of PMCs. The ice model is used to study local time dependencies of the PMC occurrence frequency, brightness and ice water content. At the station ALOMAR in Northern Norway (69°N, 16°E) we have the most ice water content with a total mean of around 90 g/km² (July 2008) in the morning hours. In the afternoons the ice water content decreases to 10 g/km² and increases again in the evening hours to 50 g/km². Tidal variability will impact results of long-term PMC observations which do not cover the full diurnal cycle. To investigate the local time dependence of PMCs in its entirety, ground-based remote sensing instruments, e.g., lidars are usefull. Variations in PMCs relating to occurrence frequency and brightness as function of local time had been already observed with the ALOMAR Rayleigh/Mie/Raman lidar. But lidar measurements offer only observations at a single local station. Models give the opportunity of a global perspective on a possible local time dependence of PMCs. In this context we will present latitudinal variations regarding to local time dependence. The combination of further observations and modeling studies can help to understand
NASA Technical Reports Server (NTRS)
Duffy, Stephen F.; Gyekenyesi, John P.
1989-01-01
Presently there are many opportunities for the application of ceramic materials at elevated temperatures. In the near future ceramic materials are expected to supplant high temperature metal alloys in a number of applications. It thus becomes essential to develop a capability to predict the time-dependent response of these materials. The creep rupture phenomenon is discussed, and a time-dependent reliability model is outlined that integrates continuum damage mechanics principles and Weibull analysis. Several features of the model are presented in a qualitative fashion, including predictions of both reliability and hazard rate. In addition, a comparison of the continuum and the microstructural kinetic equations highlights a strong resemblance in the two approaches.
3-D modelling of seamount topography from satellite altimetry
Baudry, N. ); Calmant, S. )
1991-06-01
The authors develop a complete set of algorithms to perform 3D modelling of seamount bathymetry from satellite altimetry. The first stage of the data processing consists in gridding the geoid: to account for the long wavelength errors geoid heights are first bias-adjusted at cross-overs. Then a collocation on a regular grid is performed, accounting for the altimeter errors. In a second stage, geoid heights are converted into bathymetry. No simplifying assumption on the shape and location of the bathymetry highs is necessary. Bathymetric uncertainties due to the data sampling and the parameters of the mechanical and crustal models are evaluated.
Discrete Method of Images for 3D Radio Propagation Modeling
NASA Astrophysics Data System (ADS)
Novak, Roman
2016-09-01
Discretization by rasterization is introduced into the method of images (MI) in the context of 3D deterministic radio propagation modeling as a way to exploit spatial coherence of electromagnetic propagation for fine-grained parallelism. Traditional algebraic treatment of bounding regions and surfaces is replaced by computer graphics rendering of 3D reflections and double refractions while building the image tree. The visibility of reception points and surfaces is also resolved by shader programs. The proposed rasterization is shown to be of comparable run time to that of the fundamentally parallel shooting and bouncing rays. The rasterization does not affect the signal evaluation backtracking step, thus preserving its advantage over the brute force ray-tracing methods in terms of accuracy. Moreover, the rendering resolution may be scaled back for a given level of scenario detail with only marginal impact on the image tree size. This allows selection of scene optimized execution parameters for faster execution, giving the method a competitive edge. The proposed variant of MI can be run on any GPU that supports real-time 3D graphics.
3D Numerical Simulations of the Breakout Model
NASA Astrophysics Data System (ADS)
Choe, G. S.; Cheng, C. Z.; Lee, J.; Lynch, B. J.; Antiochos, S. K.; DeVore, C. R.; Zurbuchen, T. H.
2005-05-01
We present the continuing progress of the numerical simulations of the breakout model for coronal mass ejection initiation. To validate the 3D spherical ARMS code we have run the 2.5D breakout problem and compare the eruption to the published 2D results. The ARMS 2.5D CME also forms a large magnetic island ahead of the erupting plasmoid due to the code's excellent maintenance of equatorial symmetry. Progress on the fully 3D breakout problem is also discussed. To build up enough magnetic free energy for an eruption the active region field must be strong with a steep gradient near the polarity inversion line and the shear must be highly concentrated there. This requires adaptive griding techniques. In the current simulation, the active region to background field ratio is 20-to-1 and the neutral line is long compared to the active region width. We present the evolution of this topology under Br-conserving shearing flow and discuss implications for a 3D eruption. This work is supported by NASA and ONR. BJL is supported by NASA GSRP grant NGT5-50453.
Exact numerical solution for a time-dependent fibre-bundle model with continuous damage
NASA Astrophysics Data System (ADS)
Moral, L.; Gómez, J. B.; Moreno, Y.; Pacheco, A. F.
2001-11-01
A time-dependent global fibre-bundle model of fracture with continuous damage was recently formulated in terms of an autonomous differential system and numerically solved by applying a discrete probabilistic method. In this paper we provide a method to obtain the exact numerical solution for this problem. It is based on the introduction of successive integrating parameters which permits a robust inversion of the numerical integrations appearing in the problem.
A simulation model of time-dependent plasma-spacecraft interactions
NASA Technical Reports Server (NTRS)
Rothwell, P. L.; Rubin, A. G.; Yates, G. K.
1977-01-01
A plasma simulation code is presented that models the time-dependent plasma properties in the vicinity of a spherical, charged spacecraft. After showing agreement with analytic, steady-state theories and ATS-6 satellite data, the following three problems are treated: (1) transient pulses from photoemission at various emission temperatures and ambient plasma conditions, (2) spacecharge limited emission, and (3) simulated plasma oscillations in the long wavelength limit.
3D Building Evacuation Route Modelling and Visualization
NASA Astrophysics Data System (ADS)
Chan, W.; Armenakis, C.
2014-11-01
The most common building evacuation approach currently applied is to have evacuation routes planned prior to these emergency events. These routes are usually the shortest and most practical path from each building room to the closest exit. The problem with this approach is that it is not adaptive. It is not responsively configurable relative to the type, intensity, or location of the emergency risk. Moreover, it does not provide any information to the affected persons or to the emergency responders while not allowing for the review of simulated hazard scenarios and alternative evacuation routes. In this paper we address two main tasks. The first is the modelling of the spatial risk caused by a hazardous event leading to choosing the optimal evacuation route for a set of options. The second is to generate a 3D visual representation of the model output. A multicriteria decision making (MCDM) approach is used to model the risk aiming at finding the optimal evacuation route. This is achieved by using the analytical hierarchy process (AHP) on the criteria describing the different alternative evacuation routes. The best route is then chosen to be the alternative with the least cost. The 3D visual representation of the model displays the building, the surrounding environment, the evacuee's location, the hazard location, the risk areas and the optimal evacuation pathway to the target safety location. The work has been performed using ESRI's ArcGIS. Using the developed models, the user can input the location of the hazard and the location of the evacuee. The system then determines the optimum evacuation route and displays it in 3D.
Mathematical analysis of a power-law form time dependent vector-borne disease transmission model.
Sardar, Tridip; Saha, Bapi
2017-03-06
In the last few years, fractional order derivatives have been used in epidemiology to capture the memory phenomena. However, these models do not have proper biological justification in most of the cases and lack a derivation from a stochastic process. In this present manuscript, using theory of a stochastic process, we derived a general time dependent single strain vector borne disease model. It is shown that under certain choice of time dependent transmission kernel this model can be converted into the classical integer order system. When the time-dependent transmission follows a power law form, we showed that the model converted into a vector borne disease model with fractional order transmission. We explicitly derived the disease-free and endemic equilibrium of this new fractional order vector borne disease model. Using mathematical properties of nonlinear Volterra type integral equation it is shown that the unique disease-free state is globally asymptotically stable under certain condition. We define a threshold quantity which is epidemiologically known as the basic reproduction number (R0). It is shown that if R0 > 1, then the derived fractional order model has a unique endemic equilibrium. We analytically derived the condition for the local stability of the endemic equilibrium. To test the model capability to capture real epidemic, we calibrated our newly proposed model to weekly dengue incidence data of San Juan, Puerto Rico for the time period 30th April 1994 to 23rd April 1995. We estimated several parameters, including the order of the fractional derivative of the proposed model using aforesaid data. It is shown that our proposed fractional order model can nicely capture real epidemic.
Modeling the GFR with RELAP5-3D
Cliff B. Davis; Theron D. Marshall; K. D. Weaver
2005-09-01
Significant improvements have been made to the RELAP5-3D computer code for analysis of the Gas Fast Reactor (GFR). These improvements consisted of adding carbon dioxide as a working fluid, improving the turbine component, developing a compressor model, and adding the Gnielinski heat transfer correlation. The code improvements were validated, generally through comparisons with independent design calculations. A model of the power conversion unit of the GFR was developed. The model of the power conversion unit was coupled to a reactor model to develop a complete model of the GFR system. The RELAP5 model of the GFR was used to simulate two transients, one initiated by a reactor trip and the other initiated by a loss of load.
Modeling radiative transfer in heterogeneous 3D vegetation canopies
NASA Astrophysics Data System (ADS)
Gastellu-Etchegorry, J. P.; Demarez, V.; Pinel, Veronique; Zagolski, Francis
1995-01-01
The DART (discrete anisotropic radiative transfer) model simulates radiative transfer in heterogeneous 3-D scenes; here, a forest plantation. Similarly to Kimes model, the scene is divided into a rectangular cell matrix, i.e., a building block for simulating larger scenes. Cells are parallelipipedic. The scene encompasses different landscape features (i.e., trees with leaves and trunks, grass, water, and soil) with specific optical (reflectance, transmittance) and structural (LAI, LAD) characteristics. Radiation directions are subdivided into contiguous sectors with possibly uneven spacing. Topography, hot spot, and multiple interactions (scattering, attenuation) within cells are modeled. Two major steps are distinguished: (1) Illumination of cells by direct sun radiation. Actual locations of within cell scattering are determined for optimizing scattering computation. (2) Interception and scattering of previously scattered radiation. Diffuse atmospheric radiation is input at this level. Multiple scattering is represented with a spherical harmonic decomposition, for reducing data volume. The model iterates on step 2 for all cells, and stops with the energetic equilibrium. This model predicts the bi-directional reflectance factors of 3D canopies, with each scene component contribution; it was successfully tested with homogeneous covers. It gives also the radiation regime with canopies, and consequently some information about volume distribution of photosynthesis rates and primary production.
Complex tephra dispersion from 3D plume modeling using ATHAM
NASA Astrophysics Data System (ADS)
Nicholson, B. C.; Kobs-Nawotniak, S. E.
2014-12-01
Most volcanic hazard assessments are based on a classic inversion tool for tephra deposits that relies on a simple integral model to explain the eruption plume. While this tool is adequate for first-order predictions of tephra deposition under no-wind conditions, the simplifying assumptions make it unreliable for ambient winds >10 m/s. Advances in computational power now make it possible to improve the inversion tool using 3D fluid dynamics. We do this with the physics-based Active Tracer High-resolution Atmospheric Model (ATHAM) to model tephra dispersion and deposition from volcanic eruption columns. The model, when run in 3D, is able to capture the complex morphology of bent plumes. Tephra distributions produced by these morphologies differ significantly from distributions created by idealized advection solutions, reflecting the effects of counter-rotating vortex pairs, puffing modes, or plume bifurcation. The modeled tephra deposition better captures the complex effects of wind-plume interaction, allowing us to update classic inversion tools with more realistic weak plume conditions consistent with typical historical explosive eruptions.
Testing Mercury Porosimetry with 3D Printed Porosity Models
NASA Astrophysics Data System (ADS)
Hasiuk, F.; Ewing, R. P.; Hu, Q.
2014-12-01
Mercury intrusion porosimetry is one of the most widely used techniques to study the porous nature of a geological and man-made materials. In the geosciences, it is commonly used to describe petroleum reservoir and seal rocks as well as to grade aggregates for the design of asphalt and portland cement concretes. It's wide utility stems from its ability to characterize a wide range of pore throat sizes (from nanometers to around a millimeter). The fundamental physical model underlying mercury intrusion porosimetry, the Washburn Equation, is based on the assumption that rock porosity can be described as a bundle of cylindrical tubes. 3D printing technology, also known as rapid prototyping, allows the construction of intricate and accurate models, exactly what is required to build models of rock porosity. We evaluate the applicability of the Washburn Equation by comparing properties (like porosity, pore and pore throat size distribution, and surface area) computed on digital porosity models (built from CT data, CAD designs, or periodic geometries) to properties measured via mercury intrusion porosimetry on 3D printed versions of the same digital porosity models.
3-D physical modeling of a complex salt canopy
Wiley, R.W.; Sekharan, K.K.
1996-12-31
Recent drilling has confirmed both significant reservoir potential and the presence of commercial hydrocarbons below salt structures in the Gulf of Mexico. Obtaining definitive seismic images with standard processing schemes beneath these salt structures is very difficult if not impossible. Because of the complicated seismic behavior of these structures, full volume 3-D prestack depth migration is required. Unfortunately, carrying out the multitude of calculations needed to create a proper image requires the largest and fastest supercomputers and rather complex numerical algorithms. Furthermore, developing and testing the imaging algorithms is quite involved and requires appropriate test data sets. To better understand the problems and issues of subsalt imaging, Marathon Oil Company and Louisiana Land and Exploration Company contracted with the University of Houston`s Allied Geophysical Laboratories (AGL) to construct a salt canopy physical model. The model is patterned after the SEG/EAEG Salt Model and is made from synthetic materials. It is a full three-dimensional model with an irregularly shaped, lateral salt structure embedded in five distinct sedimentary layers. The model was used to acquire a multi-offset 3-D marine-style survey. These data are being used to address problems of subsalt imaging. In addition to standard processing techniques, the authors investigate algorithms for multiple removal and prestack depth migration.
DYNA3D Material Model 71 - Solid Element Test Problem
Zywicz, E
2008-01-24
A general phenomenological-based elasto-plastic nonlinear isotropic strain hardening material model was implemented in DYNA3D for use in solid, beam, truss, and shell elements. The constitutive model, Model 71, is based upon conventional J2 plasticity and affords optional temperature and rate dependence (visco-plasticity). The expressions for strain hardening, temperature dependence, and rate dependence allow it to represent a wide variety of material responses. Options to capture temperature changes due to adiabatic heating and thermal straining are incorporated into the constitutive framework as well. The verification problem developed for this constitutive model consists of four uni-axial right cylinders subject to constant true strain-rate boundary conditions. Three of the specimens have different constant strain rates imposed, while the fourth specimen is subjected to several strain rate jumps. The material parameters developed by Fehlmann (2005) for 21-6-9 Nitronic steel are utilized. As demonstrated below, the finite element (FE) simulations are in excellent agreement with the theoretical responses and indicated the model is functioning as desired. Consequently, this problem serves as both a verification problem and regression test problem for DYNA3D.
Exploiting Textured 3D Models for Developing Serious Games
NASA Astrophysics Data System (ADS)
Kontogianni, G.; Georgopoulos, A.
2015-08-01
Digital technologies have affected significantly many fields of computer graphics such as Games and especially the field of the Serious Games. These games are usually used for educational proposes in many fields such as Health Care, Military applications, Education, Government etc. Especially Digital Cultural Heritage is a scientific area that Serious Games are applied and lately many applications appear in the related literature. Realistic 3D textured models which have been produced using different photogrammetric methods could be a useful tool for the creation of Serious Game applications in order to make the final result more realistic and close to the reality. The basic goal of this paper is how 3D textured models which are produced by photogrammetric methods can be useful for developing a more realistic environment of a Serious Game. The application of this project aims at the creation of an educational game for the Ancient Agora of Athens. The 3D models used vary not only as far as their production methods (i.e. Time of Flight laser scanner, Structure from Motion, Virtual historical reconstruction etc.) is concerned, but also as far as their era as some of them illustrated according to their existing situation and some others according to how these monuments looked like in the past. The Unity 3D® game developing environment was used for creating this application, in which all these models were inserted in the same file format. For the application two diachronic virtual tours of the Athenian Agora were produced. The first one illustrates the Agora as it is today and the second one at the 2nd century A.D. Finally the future perspective for the evolution of this game is presented which includes the addition of some questions that the user will be able to answer. Finally an evaluation is scheduled to be performed at the end of the project.
3D model tools for architecture and archaeology reconstruction
NASA Astrophysics Data System (ADS)
Vlad, Ioan; Herban, Ioan Sorin; Stoian, Mircea; Vilceanu, Clara-Beatrice
2016-06-01
The main objective of architectural and patrimonial survey is to provide a precise documentation of the status quo of the surveyed objects (monuments, buildings, archaeological object and sites) for preservation and protection, for scientific studies and restoration purposes, for the presentation to the general public. Cultural heritage documentation includes an interdisciplinary approach having as purpose an overall understanding of the object itself and an integration of the information which characterize it. The accuracy and the precision of the model are directly influenced by the quality of the measurements realized on field and by the quality of the software. The software is in the process of continuous development, which brings many improvements. On the other side, compared to aerial photogrammetry, close range photogrammetry and particularly architectural photogrammetry is not limited to vertical photographs with special cameras. The methodology of terrestrial photogrammetry has changed significantly and various photographic acquisitions are widely in use. In this context, the present paper brings forward a comparative study of TLS (Terrestrial Laser Scanner) and digital photogrammetry for 3D modeling. The authors take into account the accuracy of the 3D models obtained, the overall costs involved for each technology and method and the 4th dimension - time. The paper proves its applicability as photogrammetric technologies are nowadays used at a large scale for obtaining the 3D model of cultural heritage objects, efficacious in their assessment and monitoring, thus contributing to historic conservation. Its importance also lies in highlighting the advantages and disadvantages of each method used - very important issue for both the industrial and scientific segment when facing decisions such as in which technology to invest more research and funds.
The Engelbourg's ruins: from 3D TLS point cloud acquisition to 3D virtual and historic models
NASA Astrophysics Data System (ADS)
Koehl, Mathieu; Berger, Solveig; Nobile, Sylvain
2014-05-01
The Castle of Engelbourg was built at the beginning of the 13th century, at the top of the Schlossberg. It is situated on the territory of the municipality of Thann (France), at the crossroads of Alsace and Lorraine, and dominates the outlet of the valley of Thur. Its strategic position was one of the causes of its systematic destructions during the 17th century, and Louis XIV finished his fate by ordering his demolition in 1673. Today only few vestiges remain, of which a section of the main tower from about 7m of diameter and 4m of wide laying on its slice, unique characteristic in the regional castral landscape. It is visible since the valley, was named "the Eye of the witch", and became a key attraction of the region. The site, which extends over approximately one hectare, is for several years the object of numerous archaeological studies and is at the heart of a project of valuation of the vestiges today. It was indeed a key objective, among the numerous planned works, to realize a 3D model of the site in its current state, in other words, a virtual model "such as seized", exploitable as well from a cultural and tourist point of view as by scientists and in archaeological researches. The team of the ICube/INSA lab had in responsibility the realization of this model, the acquisition of the data until the delivery of the virtual model, thanks to 3D TLS and topographic surveying methods. It was also planned to integrate into this 3D model, data of 2D archives, stemming from series of former excavations. The objectives of this project were the following ones: • Acquisition of 3D digital data of the site and 3D modelling • Digitization of the 2D archaeological data and integration in the 3D model • Implementation of a database connected to the 3D model • Virtual Visit of the site The obtained results allowed us to visualize every 3D object individually, under several forms (point clouds, 3D meshed objects and models, etc.) and at several levels of detail
3-D Modeling of a Nearshore Dye Release
NASA Astrophysics Data System (ADS)
Maxwell, A. R.; Hibler, L. F.; Miller, L. M.
2006-12-01
The usage of computer modeling software in predicting the behavior of a plume discharged into deep water is well established. Nearfield plume spreading in coastal areas with complex bathymetry is less commonly studied; in addition to geometry, some of the difficulties of this environment include: tidal exchange, temperature, and salinity gradients. Although some researchers have applied complex hydrodynamic models to this problem, nearfield regions are typically modeled by calibration of an empirical or expert system model. In the present study, the 3D hydrodynamic model Delft3D-FLOW was used to predict the advective transport from a point release in Sequim Bay, Washington. A nested model approach was used, wherein a coarse model using a mesh extending to nearby tide gages (cell sizes up to 1 km) was run over several tidal cycles in order to provide boundary conditions to a smaller area. The nested mesh (cell sizes up to 30 m) was forced on two open boundaries using the water surface elevation derived from the coarse model. Initial experiments with the uncalibrated model were conducted in order to predict plume propagation based on the best available field data. Field experiments were subsequently carried out by releasing rhodamine dye into the bay at near-peak flood tidal current and near high slack tidal conditions. Surface and submerged releases were carried out from an anchored vessel. Concurrently collected data from the experiment include temperature, salinity, dye concentration, and hyperspectral imagery, collected from boats and aircraft. A REMUS autonomous underwater vehicle was used to measure current velocity and dye concentration at varying depths, as well as to acquire additional bathymetric information. Preliminary results indicate that the 3D hydrodynamic model offers a reasonable prediction of plume propagation speed and shape. A sensitivity analysis is underway to determine the significant factors in effectively using the model as a predictive tool
Discussion of Source Reconstruction Models Using 3D MCG Data
NASA Astrophysics Data System (ADS)
Melis, Massimo De; Uchikawa, Yoshinori
In this study we performed the source reconstruction of magnetocardiographic signals generated by the human heart activity to localize the site of origin of the heart activation. The localizations were performed in a four compartment model of the human volume conductor. The analyses were conducted on normal subjects and on a subject affected by the Wolff-Parkinson-White syndrome. Different models of the source activation were used to evaluate whether a general model of the current source can be applied in the study of the cardiac inverse problem. The data analyses were repeated using normal and vector component data of the MCG. The results show that a distributed source model has the better accuracy in performing the source reconstructions, and that 3D MCG data allow finding smaller differences between the different source models.
Nascimento, Daniel R.; DePrince, A. Eugene
2015-12-07
We present a combined cavity quantum electrodynamics/ab initio electronic structure approach for simulating plasmon-molecule interactions in the time domain. The simple Jaynes-Cummings-type model Hamiltonian typically utilized in such simulations is replaced with one in which the molecular component of the coupled system is treated in a fully ab initio way, resulting in a computationally efficient description of general plasmon-molecule interactions. Mutual polarization effects are easily incorporated within a standard ground-state Hartree-Fock computation, and time-dependent simulations carry the same formal computational scaling as real-time time-dependent Hartree-Fock theory. As a proof of principle, we apply this generalized method to the emergence of a Fano-like resonance in coupled molecule-plasmon systems; this feature is quite sensitive to the nanoparticle-molecule separation and the orientation of the molecule relative to the polarization of the external electric field.
Absorption and injection models for open time-dependent quantum systems.
Traversa, F L; Zhan, Z; Oriols, X
2014-08-01
In the time-dependent simulation of pure states dealing with transport in open quantum systems, the initial state is located outside of the active region of interest. Using the superposition principle and the analytical knowledge of the free time evolution of such a state outside the active region, together with absorbing layers and remapping, a model for a very significant reduction of the computational burden associated with the numerical simulation of open time-dependent quantum systems is presented. The model is specially suited to study (many-particle and high-frequency effects) quantum transport, but it can also be applied to any other research field where the initial time-dependent pure state is located outside of the active region. From numerical simulations of open quantum systems described by the (effective mass) Schrödinger and (atomistic) tight-binding equations, a reduction of the computational burden of about two orders of magnitude for each spatial dimension of the domain with a negligible error is presented.
NASA Astrophysics Data System (ADS)
Oh, Yun-Tak; Higashi, Yoichi; Chan, Ching-Kit; Han, Jung Hoon
2016-08-01
The Lang-Firsov Hamiltonian, a well-known solvable model of interacting fermion-boson system with sideband features in the fermion spectral weight, is generalized to have the time-dependent fermion-boson coupling constant. We show how to derive the two-time Green's function for the time-dependent problem in the adiabatic limit, defined as the slow temporal variation of the coupling over the characteristic oscillator period. The idea we use in deriving the Green's function is akin to the use of instantaneous basis states in solving the adiabatic evolution problem in quantum mechanics. With such "adiabatic Green's function" at hand we analyze the transient behavior of the spectral weight as the coupling is gradually tuned to zero. Time-dependent generalization of a related model, the spin-boson Hamiltonian, is analyzed in the same way. In both cases the sidebands arising from the fermion-boson coupling can be seen to gradually lose their spectral weights over time. Connections of our solution to the two-dimensional Dirac electrons coupled to quantized photons are discussed.
NASA Astrophysics Data System (ADS)
Reyes, J. Paxon; Shadwick, B. A.
2015-11-01
Describing a cold-Maxwell fluid system with a spatially-discrete, unbounded Lagrangian is problematic for numerical modeling since boundary conditions must be applied after the variational step. Accurate solutions may still be attained, but do not technically satisfy the derived energy conservation law. The size of the numerical domain, the order accuracy of the discrete approximations used, and the type of boundary conditions applied influence the behavior of the artificially-bounded system. To encode the desired boundary conditions of the equations of motion, we include time-dependent terms into the discrete Lagrangian. Although some foresight is needed to choose these time-dependent terms, this approach provides a mechanism for energy to exit the closed system while allowing the conservation law to account for the energy loss. Results of a spatially-discrete, time-dependent Lagrangian system (with approximations of second-order accuracy in space and fourth order in time) will be presented. The fields and total energy will be compared with models of the same accuracy using a time-independent variational approach as well as a non-variational approach. This work was supported by the U. S. Department of Energy under Contract No. DE-SC0008382 and by the National Science Foundation under Contract No. PHY- 1104683.
Absorption and injection models for open time-dependent quantum systems
NASA Astrophysics Data System (ADS)
Traversa, F. L.; Zhan, Z.; Oriols, X.
2014-08-01
In the time-dependent simulation of pure states dealing with transport in open quantum systems, the initial state is located outside of the active region of interest. Using the superposition principle and the analytical knowledge of the free time evolution of such a state outside the active region, together with absorbing layers and remapping, a model for a very significant reduction of the computational burden associated with the numerical simulation of open time-dependent quantum systems is presented. The model is specially suited to study (many-particle and high-frequency effects) quantum transport, but it can also be applied to any other research field where the initial time-dependent pure state is located outside of the active region. From numerical simulations of open quantum systems described by the (effective mass) Schrödinger and (atomistic) tight-binding equations, a reduction of the computational burden of about two orders of magnitude for each spatial dimension of the domain with a negligible error is presented.
Modeling moving systems with RELAP5-3D
Mesina, G. L.; Aumiller, David L.; Buschman, Francis X.; ...
2015-12-04
RELAP5-3D is typically used to model stationary, land-based reactors. However, it can also model reactors in other inertial and accelerating frames of reference. By changing the magnitude of the gravitational vector through user input, RELAP5-3D can model reactors on a space station or the moon. The field equations have also been modified to model reactors in a non-inertial frame, such as occur in land-based reactors during earthquakes or onboard spacecraft. Transient body forces affect fluid flow in thermal-fluid machinery aboard accelerating crafts during rotational and translational accelerations. It is useful to express the equations of fluid motion in the acceleratingmore » frame of reference attached to the moving craft. However, careful treatment of the rotational and translational kinematics is required to accurately capture the physics of the fluid motion. Correlations for flow at angles between horizontal and vertical are generated via interpolation where no experimental studies or data exist. The equations for three-dimensional fluid motion in a non-inertial frame of reference are developed. As a result, two different systems for describing rotational motion are presented, user input is discussed, and an example is given.« less
Modeling moving systems with RELAP5-3D
Mesina, G. L.; Aumiller, David L.; Buschman, Francis X.; Kyle, Matt R.
2015-12-04
RELAP5-3D is typically used to model stationary, land-based reactors. However, it can also model reactors in other inertial and accelerating frames of reference. By changing the magnitude of the gravitational vector through user input, RELAP5-3D can model reactors on a space station or the moon. The field equations have also been modified to model reactors in a non-inertial frame, such as occur in land-based reactors during earthquakes or onboard spacecraft. Transient body forces affect fluid flow in thermal-fluid machinery aboard accelerating crafts during rotational and translational accelerations. It is useful to express the equations of fluid motion in the accelerating frame of reference attached to the moving craft. However, careful treatment of the rotational and translational kinematics is required to accurately capture the physics of the fluid motion. Correlations for flow at angles between horizontal and vertical are generated via interpolation where no experimental studies or data exist. The equations for three-dimensional fluid motion in a non-inertial frame of reference are developed. As a result, two different systems for describing rotational motion are presented, user input is discussed, and an example is given.
Fisheye Lenses for 3d Modeling: Evaluations and Considerations
NASA Astrophysics Data System (ADS)
Barazzetti, L.; Previtali, M.; Roncoroni, F.
2017-02-01
Fisheye lenses are becoming more popular in complete image-based modelling projects of small and narrow spaces. The growing interest in fisheye lenses is confirmed by the availability of different commercial software incorporating a fisheye camera model. Such software are now able to carry out the steps of the image processing pipeline in a fully automated way, from camera calibration and orientation to dense matching, surface generation, and orthophoto production. This paper highlights the advantages (and disadvantages) of fisheye lenses when used for 3D modelling projects through different commercial software. The goal is not only a comparison of commercial software, but also an analysis of the additional issues that arise when a fisheye lens is used for 3D modelling. Results confirm that a fisheye lens is suitable for accurate metric documentation, especially when limited space is available. On the other hand, additional issues where found during the camera calibration/image orientation step as well as the texture generation and orthophoto production phases, for which particular attention is required.
Reassessing Geophysical Models of the Bushveld Complex in 3D
NASA Astrophysics Data System (ADS)
Cole, J.; Webb, S. J.; Finn, C.
2012-12-01
Conceptual geophysical models of the Bushveld Igneous Complex show three possible geometries for its mafic component: 1) Separate intrusions with vertical feeders for the eastern and western lobes (Cousins, 1959) 2) Separate dipping sheets for the two lobes (Du Plessis and Kleywegt, 1987) 3) A single saucer-shaped unit connected at depth in the central part between the two lobes (Cawthorn et al, 1998) Model three incorporates isostatic adjustment of the crust in response to the weight of the dense mafic material. The model was corroborated by results of a broadband seismic array over southern Africa, known as the Southern African Seismic Experiment (SASE) (Nguuri, et al, 2001; Webb et al, 2004). This new information about the crustal thickness only became available in the last decade and could not be considered in the earlier models. Nevertheless, there is still on-going debate as to which model is correct. All of the models published up to now have been done in 2 or 2.5 dimensions. This is not well suited to modelling the complex geometry of the Bushveld intrusion. 3D modelling takes into account effects of variations in geometry and geophysical properties of lithologies in a full three dimensional sense and therefore affects the shape and amplitude of calculated fields. The main question is how the new knowledge of the increased crustal thickness, as well as the complexity of the Bushveld Complex, will impact on the gravity fields calculated for the existing conceptual models, when modelling in 3D. The three published geophysical models were remodelled using full 3Dl potential field modelling software, and including crustal thickness obtained from the SASE. The aim was not to construct very detailed models, but to test the existing conceptual models in an equally conceptual way. Firstly a specific 2D model was recreated in 3D, without crustal thickening, to establish the difference between 2D and 3D results. Then the thicker crust was added. Including the less
A generic 3D kinetic model of gene expression
NASA Astrophysics Data System (ADS)
Zhdanov, Vladimir P.
2012-04-01
Recent experiments show that mRNAs and proteins can be localized both in prokaryotic and eukaryotic cells. To describe such situations, I present a 3D mean-field kinetic model aimed primarily at gene expression in prokaryotic cells, including the formation of mRNA, its translation into protein, and slow diffusion of these species. Under steady-state conditions, the mRNA and protein spatial distribution is described by simple exponential functions. The protein concentration near the gene transcribed into mRNA is shown to depend on the protein and mRNA diffusion coefficients and degradation rate constants.
3-d Periodic Packaging: Sodalite, a Model System
1992-05-15
to 05-31-92 4. TITLE AND SUBTITLE S. FUNDING NUMBERS 3-d Periodic Packaging: N00014-90-J-1159 Sodalite , A Model System 6. AUTHOR(S) G.D. Stucky, V.I...assembly of confined atomic and molecular arrays. Sodalite , one of the simplest zeolite analogue structures with a 60 atom cage can be synthesized with...structure of both the frameworks and the clusters within the cages of sodalite structural analogues can be precisely determined. In addition to new
3-D Periodic Packaging: Sodalite, a Model System
1992-05-15
hfww 05-15-92 Technical 06-1-91 o 05-31-92 ,mA AMU SUBSTIl SI. FUNDING NUMBUS 3-d Periodic Packaging: Sodalite , A Model System N00014-81-K-0598 AUTNO(S...considerable latitude in the assembly of confined atomic and molecular arrays. Sodalite , one of the simplest zeolite analogue structures with a 60 atom...framework electric field. The structure of both the fiameworks and the clusters within the cages of sodalite structural analogues can be precisely
3D simulation of the Cluster-Cluster Aggregation model
NASA Astrophysics Data System (ADS)
Li, Chao; Xiong, Hailing
2014-12-01
We write a program to implement the Cluster-Cluster Aggregation (CCA) model with java programming language. By using the simulation program, the fractal aggregation growth process can be displayed dynamically in the form of a three-dimensional (3D) figure. Meanwhile, the related kinetics data of aggregation simulation can be also recorded dynamically. Compared to the traditional programs, the program has better real-time performance and is more helpful to observe the fractal growth process, which contributes to the scientific study in fractal aggregation. Besides, because of adopting java programming language, the program has very good cross-platform performance.
3D modeling of electromagnetically launched thin metal rings
NASA Astrophysics Data System (ADS)
Chantrenne, Sophie; Robinson, Allen C.; Siefert, Christopher; Strack, O. Erik; Hensinger, David M.; Gourdin, William H.
2011-06-01
Electromagnetically driving thin metal rings is an effective method to study materials under high-strain-rate loading conditions, as well as fragmentation of specimen. To better understand the technique, 3-D calculations of the ring expansion and fragmentation for different metals were performed using the ALEGRA MHD code. To assess the validity of our model, the results of our simulations are compared to measurements made at Lawrence Livermore National Laboratory. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.
NASA Astrophysics Data System (ADS)
Bournez, E.; Landes, T.; Saudreau, M.; Kastendeuch, P.; Najjar, G.
2017-02-01
3D models of tree geometry are important for numerous studies, such as for urban planning or agricultural studies. In climatology, tree models can be necessary for simulating the cooling effect of trees by estimating their evapotranspiration. The literature shows that the more accurate the 3D structure of a tree is, the more accurate microclimate models are. This is the reason why, since 2013, we have been developing an algorithm for the reconstruction of trees from terrestrial laser scanner (TLS) data, which we call TreeArchitecture. Meanwhile, new promising algorithms dedicated to tree reconstruction have emerged in the literature. In this paper, we assess the capacity of our algorithm and of two others -PlantScan3D and SimpleTree- to reconstruct the 3D structure of trees. The aim of this reconstruction is to be able to characterize the geometric complexity of trees, with different heights, sizes and shapes of branches. Based on a specific surveying workflow with a TLS, we have acquired dense point clouds of six different urban trees, with specific architectures, before reconstructing them with each algorithm. Finally, qualitative and quantitative assessments of the models are performed using reference tree reconstructions and field measurements. Based on this assessment, the advantages and the limits of every reconstruction algorithm are highlighted. Anyway, very satisfying results can be reached for 3D reconstructions of tree topology as well as of tree volume.
El-Hamidi, Hamid; Celli, Jonathan P.
2014-01-01
The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and modified as part of a set of complex, two-way mechanosensitive interactions. While the development of biologically-relevant 3D tumor models have facilitated mechanistic studies on the impact of matrix rheology on tumor growth, the inverse problem of mapping changes in the mechanical environment induced by tumors remains challenging. Here, we describe the implementation of particle-tracking microrheology (PTM) in conjunction with 3D models of pancreatic cancer as part of a robust and viable approach for longitudinally monitoring physical changes in the tumor microenvironment, in situ. The methodology described here integrates a system of preparing in vitro 3D models embedded in a model extracellular matrix (ECM) scaffold of Type I collagen with fluorescently labeled probes uniformly distributed for position- and time-dependent microrheology measurements throughout the specimen. In vitro tumors are plated and probed in parallel conditions using multiwell imaging plates. Drawing on established methods, videos of tracer probe movements are transformed via the Generalized Stokes Einstein Relation (GSER) to report the complex frequency-dependent viscoelastic shear modulus, G*(ω). Because this approach is imaging-based, mechanical characterization is also mapped onto large transmitted-light spatial fields to simultaneously report qualitative changes in 3D tumor size and phenotype. Representative results showing contrasting mechanical response in sub-regions associated with localized invasion-induced matrix degradation as well as system calibration, validation data are presented. Undesirable outcomes from common experimental errors and troubleshooting of these issues are also presented. The 96-well 3D culture plating format implemented in this protocol is conducive to correlation of microrheology measurements with therapeutic
3D finite element modeling of pelvic organ prolapse.
Yang, Zhuo; Hayes, Jaclyn; Krishnamurty, Sundar; Grosse, Ian R
2016-12-01
The purpose of this study is to develop a validated 3D finite element model of the pelvic floor system which can offer insights into the mechanics of anterior vaginal wall prolapse and have the ability to assess biomedical device treatment methods. The finite element results should accurately mimic the clinical findings of prolapse due to intra-abdominal pressure (IAP) and soft tissues impairment conditions. A 3D model of pelvic system was created in Creo Parametric 2.0 based on MRI Images, which included uterus, cervix, vagina, cardinal ligaments, uterosacral ligaments, and a simplified levator plate and rectum. The geometrical model was imported into ANSYS Workbench 14.5. Mechanical properties of soft tissues were based on experimental data of tensile test results from current literature. Studies were conducted for IAP loadings on the vaginal wall and uterus, increasing from lowest to extreme values. Anterior vaginal wall collapse occurred at an IAP value corresponding to maximal valsalva and showed similar collapsed shape as clinical findings. Prolapse conditions exhibited high sensitivity to vaginal wall stiffness, whereas healthy tissues was found to support the vagina against prolapse. Ligament impairment was found to have only a secondary effect on prolapse.
Image sequence coding using 3D scene models
NASA Astrophysics Data System (ADS)
Girod, Bernd
1994-09-01
The implicit and explicit use of 3D models for image sequence coding is discussed. For implicit use, a 3D model can be incorporated into motion compensating prediction. A scheme that estimates the displacement vector field with a rigid body motion constraint by recovering epipolar lines from an unconstrained displacement estimate and then repeating block matching along the epipolar line is proposed. Experimental results show that an improved displacement vector field can be obtained with a rigid body motion constraint. As an example for explicit use, various results with a facial animation model for videotelephony are discussed. A 13 X 16 B-spline mask can be adapted automatically to individual faces and is used to generate facial expressions based on FACS. A depth-from-defocus range camera suitable for real-time facial motion tracking is described. Finally, the real-time facial animation system `Traugott' is presented that has been used to generate several hours of broadcast video. Experiments suggest that a videophone system based on facial animation might require a transmission bitrate of 1 kbit/s or below.
Dualities in 3D large N vector models
NASA Astrophysics Data System (ADS)
Muteeb, Nouman; Zayas, Leopoldo A. Pando; Quevedo, Fernando
2016-05-01
Using an explicit path integral approach we derive non-abelian bosonization and duality of 3D systems in the large N limit. We first consider a fermionic U( N) vector model coupled to level k Chern-Simons theory, following standard techniques we gauge the original global symmetry and impose the corresponding field strength F μν to vanish introducing a Lagrange multiplier Λ. Exchanging the order of integrations we obtain the bosonized theory with Λ as the propagating field using the large N rather than the previously used large mass limit. Next we follow the same procedure to dualize the scalar U ( N) vector model coupled to Chern-Simons and find its corresponding dual theory. Finally, we compare the partition functions of the two resulting theories and find that they agree in the large N limit including a level/rank duality. This provides a constructive evidence for previous proposals on level/rank duality of 3D vector models in the large N limit. We also present a partial analysis at subleading order in large N and find that the duality does not generically hold at this level.
Pose invariant face recognition: 3D model from single photo
NASA Astrophysics Data System (ADS)
Napoléon, Thibault; Alfalou, Ayman
2017-02-01
Face recognition is widely studied in the literature for its possibilities in surveillance and security. In this paper, we report a novel algorithm for the identification task. This technique is based on an optimized 3D modeling allowing to reconstruct faces in different poses from a limited number of references (i.e. one image by class/person). Particularly, we propose to use an active shape model to detect a set of keypoints on the face necessary to deform our synthetic model with our optimized finite element method. Indeed, in order to improve our deformation, we propose a regularization by distances on graph. To perform the identification we use the VanderLugt correlator well know to effectively address this task. On the other hand we add a difference of Gaussian filtering step to highlight the edges and a description step based on the local binary patterns. The experiments are performed on the PHPID database enhanced with our 3D reconstructed faces of each person with an azimuth and an elevation ranging from -30° to +30°. The obtained results prove the robustness of our new method with 88.76% of good identification when the classic 2D approach (based on the VLC) obtains just 44.97%.
Computational model of mesenchymal migration in 3D under chemotaxis.
Ribeiro, F O; Gómez-Benito, M J; Folgado, J; Fernandes, P R; García-Aznar, J M
2017-01-01
Cell chemotaxis is an important characteristic of cellular migration, which takes part in crucial aspects of life and development. In this work, we propose a novel in silico model of mesenchymal 3D migration with competing protrusions under a chemotactic gradient. Based on recent experimental observations, we identify three main stages that can regulate mesenchymal chemotaxis: chemosensing, dendritic protrusion dynamics and cell-matrix interactions. Therefore, each of these features is considered as a different module of the main regulatory computational algorithm. The numerical model was particularized for the case of fibroblast chemotaxis under a PDGF-bb gradient. Fibroblasts migration was simulated embedded in two different 3D matrices - collagen and fibrin - and under several PDGF-bb concentrations. Validation of the model results was provided through qualitative and quantitative comparison with in vitro studies. Our numerical predictions of cell trajectories and speeds were within the measured in vitro ranges in both collagen and fibrin matrices. Although in fibrin, the migration speed of fibroblasts is very low, because fibrin is a stiffer and more entangling matrix. Testing PDGF-bb concentrations, we noticed that an increment of this factor produces a speed increment. At 1 ng mL(-1) a speed peak is reached after which the migration speed diminishes again. Moreover, we observed that fibrin exerts a dampening behavior on migration, significantly affecting the migration efficiency.
Computational model of mesenchymal migration in 3D under chemotaxis
Ribeiro, F. O.; Gómez-Benito, M. J.; Folgado, J.; Fernandes, P. R.; García-Aznar, J. M.
2017-01-01
Abstract Cell chemotaxis is an important characteristic of cellular migration, which takes part in crucial aspects of life and development. In this work, we propose a novel in silico model of mesenchymal 3D migration with competing protrusions under a chemotactic gradient. Based on recent experimental observations, we identify three main stages that can regulate mesenchymal chemotaxis: chemosensing, dendritic protrusion dynamics and cell–matrix interactions. Therefore, each of these features is considered as a different module of the main regulatory computational algorithm. The numerical model was particularized for the case of fibroblast chemotaxis under a PDGF-bb gradient. Fibroblasts migration was simulated embedded in two different 3D matrices – collagen and fibrin – and under several PDGF-bb concentrations. Validation of the model results was provided through qualitative and quantitative comparison with in vitro studies. Our numerical predictions of cell trajectories and speeds were within the measured in vitro ranges in both collagen and fibrin matrices. Although in fibrin, the migration speed of fibroblasts is very low, because fibrin is a stiffer and more entangling matrix. Testing PDGF-bb concentrations, we noticed that an increment of this factor produces a speed increment. At 1 ng mL−1 a speed peak is reached after which the migration speed diminishes again. Moreover, we observed that fibrin exerts a dampening behavior on migration, significantly affecting the migration efficiency. PMID:27336322
Simulation of 3D Global Wave Propagation Through Geodynamic Models
NASA Astrophysics Data System (ADS)
Schuberth, B.; Piazzoni, A.; Bunge, H.; Igel, H.; Steinle-Neumann, G.
2005-12-01
This project aims at a better understanding of the forward problem of global 3D wave propagation. We use the spectral element program "SPECFEM3D" (Komatitsch and Tromp, 2002a,b) with varying input models of seismic velocities derived from mantle convection simulations (Bunge et al., 2002). The purpose of this approach is to obtain seismic velocity models independently from seismological studies. In this way one can test the effects of varying parameters of the mantle convection models on the seismic wave field. In order to obtain the seismic velocities from the temperature field of the geodynamical simulations we follow a mineral physics approach. Assuming a certain mantle composition (e.g. pyrolite with CMASF composition) we compute the stable phases for each depth (i.e. pressure) and temperature by system Gibbs free energy minimization. Elastic moduli and density are calculated from the equations of state of the stable mineral phases. For this we use a mineral physics database derived from calorimetric experiments (enthalphy and entropy of formation, heat capacity) and EOS parameters.
Heralding a new paradigm in 3D tumor modeling.
Fong, Eliza L S; Harrington, Daniel A; Farach-Carson, Mary C; Yu, Hanry
2016-11-01
Numerous studies to date have contributed to a paradigm shift in modeling cancer, moving from the traditional two-dimensional culture system to three-dimensional (3D) culture systems for cancer cell culture. This led to the inception of tumor engineering, which has undergone rapid advances over the years. In line with the recognition that tumors are not merely masses of proliferating cancer cells but rather, highly complex tissues consisting of a dynamic extracellular matrix together with stromal, immune and endothelial cells, significant efforts have been made to better recapitulate the tumor microenvironment in 3D. These approaches include the development of engineered matrices and co-cultures to replicate the complexity of tumor-stroma interactions in vitro. However, the tumor engineering and cancer biology fields have traditionally relied heavily on the use of cancer cell lines as a cell source in tumor modeling. While cancer cell lines have contributed to a wealth of knowledge in cancer biology, the use of this cell source is increasingly perceived as a major contributing factor to the dismal failure rate of oncology drugs in drug development. Backing this notion is the increasing evidence that tumors possess intrinsic heterogeneity, which predominantly homogeneous cancer cell lines poorly reflect. Tumor heterogeneity contributes to therapeutic resistance in patients. To overcome this limitation, cancer cell lines are beginning to be replaced by primary tumor cell sources, in the form of patient-derived xenografts and organoids cultures. Moving forward, we propose that further advances in tumor engineering would require that tumor heterogeneity (tumor variants) be taken into consideration together with tumor complexity (tumor-stroma interactions). In this review, we provide a comprehensive overview of what has been achieved in recapitulating tumor complexity, and discuss the importance of incorporating tumor heterogeneity into 3D in vitro tumor models. This
Untangling Slab Dynamics Using 3-D Numerical and Analytical Models
NASA Astrophysics Data System (ADS)
Holt, A. F.; Royden, L.; Becker, T. W.
2016-12-01
Increasingly sophisticated numerical models have enabled us to make significant strides in identifying the key controls on how subducting slabs deform. For example, 3-D models have demonstrated that subducting plate width, and the related strength of toroidal flow around the plate edge, exerts a strong control on both the curvature and the rate of migration of the trench. However, the results of numerical subduction models can be difficult to interpret, and many first order dynamics issues remain at least partially unresolved. Such issues include the dominant controls on trench migration, the interdependence of asthenospheric pressure and slab dynamics, and how nearby slabs influence each other's dynamics. We augment 3-D, dynamically evolving finite element models with simple, analytical force-balance models to distill the physics associated with subduction into more manageable parts. We demonstrate that for single, isolated subducting slabs much of the complexity of our fully numerical models can be encapsulated by simple analytical expressions. Rates of subduction and slab dip correlate strongly with the asthenospheric pressure difference across the subducting slab. For double subduction, an additional slab gives rise to more complex mantle pressure and flow fields, and significantly extends the range of plate kinematics (e.g., convergence rate, trench migration rate) beyond those present in single slab models. Despite these additional complexities, we show that much of the dynamics of such multi-slab systems can be understood using the physics illuminated by our single slab study, and that a force-balance method can be used to relate intra-plate stress to viscous pressure in the asthenosphere and coupling forces at plate boundaries. This method has promise for rapid modeling of large systems of subduction zones on a global scale.
Fractional modeling of viscoelasticity in 3D cerebral arteries and aneurysms
NASA Astrophysics Data System (ADS)
Yu, Yue; Perdikaris, Paris; Karniadakis, George Em
2016-10-01
We develop efficient numerical methods for fractional order PDEs, and employ them to investigate viscoelastic constitutive laws for arterial wall mechanics. Recent simulations using one-dimensional models [1] have indicated that fractional order models may offer a more powerful alternative for modeling the arterial wall response, exhibiting reduced sensitivity to parametric uncertainties compared with the integer-calculus-based models. Here, we study three-dimensional (3D) fractional PDEs that naturally model the continuous relaxation properties of soft tissue, and for the first time employ them to simulate flow structure interactions for patient-specific brain aneurysms. To deal with the high memory requirements and in order to accelerate the numerical evaluation of hereditary integrals, we employ a fast convolution method [2] that reduces the memory cost to O (log (N)) and the computational complexity to O (Nlog (N)). Furthermore, we combine the fast convolution with high-order backward differentiation to achieve third-order time integration accuracy. We confirm that in 3D viscoelastic simulations, the integer order models strongly depends on the relaxation parameters, while the fractional order models are less sensitive. As an application to long-time simulations in complex geometries, we also apply the method to modeling fluid-structure interaction of a 3D patient-specific compliant cerebral artery with an aneurysm. Taken together, our findings demonstrate that fractional calculus can be employed effectively in modeling complex behavior of materials in realistic 3D time-dependent problems if properly designed efficient algorithms are employed to overcome the extra memory requirements and computational complexity associated with the non-local character of fractional derivatives.
The Use of Mixed Models for the Analysis of Mediated Data with Time-Dependent Predictors
Blood, Emily A.; Cheng, Debbie M.
2011-01-01
Linear mixed models (LMMs) are frequently used to analyze longitudinal data. Although these models can be used to evaluate mediation, they do not directly model causal pathways. Structural equation models (SEMs) are an alternative technique that allows explicit modeling of mediation. The goal of this paper is to evaluate the performance of LMMs relative to SEMs in the analysis of mediated longitudinal data with time-dependent predictors and mediators. We simulated mediated longitudinal data from an SEM and specified delayed effects of the predictor. A variety of model specifications were assessed, and the LMMs and SEMs were evaluated with respect to bias, coverage probability, power, and Type I error. Models evaluated in the simulation were also applied to data from an observational cohort of HIV-infected individuals. We found that when carefully constructed, the LMM adequately models mediated exposure effects that change over time in the presence of mediation, even when the data arise from an SEM. PMID:21647351
ERIC Educational Resources Information Center
Rowe, Jeremy; Razdan, Anshuman
The Partnership for Research in Spatial Modeling (PRISM) project at Arizona State University (ASU) developed modeling and analytic tools to respond to the limitations of two-dimensional (2D) data representations perceived by affiliated discipline scientists, and to take advantage of the enhanced capabilities of three-dimensional (3D) data that…
Canada in 3D - Toward a Sustainable 3D Model for Canadian Geology from Diverse Data Sources
NASA Astrophysics Data System (ADS)
Brodaric, B.; Pilkington, M.; Snyder, D. B.; St-Onge, M. R.; Russell, H.
2015-12-01
Many big science issues span large areas and require data from multiple heterogeneous sources, for example climate change, resource management, and hazard mitigation. Solutions to these issues can significantly benefit from access to a consistent and integrated geological model that would serve as a framework. However, such a model is absent for most large countries including Canada, due to the size of the landmass and the fragmentation of the source data into institutional and disciplinary silos. To overcome these barriers, the "Canada in 3D" (C3D) pilot project was recently launched by the Geological Survey of Canada. C3D is designed to be evergreen, multi-resolution, and inter-disciplinary: (a) it is to be updated regularly upon acquisition of new data; (b) portions vary in resolution and will initially consist of four layers (surficial, sedimentary, crystalline, and mantle) with intermediary patches of higher-resolution fill; and (c) a variety of independently managed data sources are providing inputs, such as geophysical, 3D and 2D geological models, drill logs, and others. Notably, scalability concerns dictate a decentralized and interoperable approach, such that only key control objects, denoting anchors for the modeling process, are imported into the C3D database while retaining provenance links to original sources. The resultant model is managed in the database, contains full modeling provenance as well as links to detailed information on rock units, and is to be visualized in desktop and online environments. It is anticipated that C3D will become the authoritative state of knowledge for the geology of Canada at a national scale.
Time-dependent ionization balance model for non-LTE plasma
Lee, Y.T.; Zimmerman, G.B.; Bailey, D.S.; Dickson, D.; Kim, D.
1986-05-07
We have developed a detailed configuration-accounting kinetic model for calculating time-dependent ionization-balance and ion-level populations in non-local thermal-equilibrium (non-LTE) plasmas. We use these population estimates in computing spectral line intensities, line ratios, and synthetic spectra, and in fitting these calculated values to experimental measurements. The model is also used to design laboratory x-ray laser experiments. For this purpose, it is self-consistently coupled to the hydrodynamics code LASNEX. 20 refs., 14 figs.
Cosmological compactification in Kaluza-Klein model and time-dependent cosmological term
NASA Astrophysics Data System (ADS)
Srivastava, S. K.
1992-12-01
Einstein's equations for the generalized (4+ D)-dimensional Robertson-Walker model are solved taking the conformally invariant action for the matter field. Compactification of this model is discussed and the compactification time/compactification mass scale for different values of D is calculated. The resulting 4-dimensional action for gravity is obtained. It is found that a time-dependent cosmological constant is induced which is very large when the cosmic time is small and very small when the cosmic time is large.
Random walk in degree space and the time-dependent Watts-Strogatz model.
Casa Grande, H L; Cotacallapa, M; Hase, M O
2017-01-01
In this work, we propose a scheme that provides an analytical estimate for the time-dependent degree distribution of some networks. This scheme maps the problem into a random walk in degree space, and then we choose the paths that are responsible for the dominant contributions. The method is illustrated on the dynamical versions of the Erdős-Rényi and Watts-Strogatz graphs, which were introduced as static models in the original formulation. We have succeeded in obtaining an analytical form for the dynamics Watts-Strogatz model, which is asymptotically exact for some regimes.
Random walk in degree space and the time-dependent Watts-Strogatz model
NASA Astrophysics Data System (ADS)
Casa Grande, H. L.; Cotacallapa, M.; Hase, M. O.
2017-01-01
In this work, we propose a scheme that provides an analytical estimate for the time-dependent degree distribution of some networks. This scheme maps the problem into a random walk in degree space, and then we choose the paths that are responsible for the dominant contributions. The method is illustrated on the dynamical versions of the Erdős-Rényi and Watts-Strogatz graphs, which were introduced as static models in the original formulation. We have succeeded in obtaining an analytical form for the dynamics Watts-Strogatz model, which is asymptotically exact for some regimes.
Modeling Time-Dependent Association in Longitudinal Data: A Lag as Moderator Approach.
Selig, James P; Preacher, Kristopher J; Little, Todd D
2012-01-01
We describe a straightforward, yet novel, approach to examine time-dependent association between variables. The approach relies on a measurement-lag research design in conjunction with statistical interaction models. We base arguments in favor of this approach on the potential for better understanding the associations between variables by describing how the association changes with time. We introduce a number of different functional forms for describing these lag-moderated associations, each with a different substantive meaning. Finally, we use empirical data to demonstrate methods for exploring functional forms and model fitting based on this approach.
Comparative 3-D modeling of tmRNA.
Burks, Jody; Zwieb, Christian; Müller, Florian; Wower, Iwona; Wower, Jacek
2005-06-15
Trans-translation releases stalled ribosomes from truncated mRNAs and tags defective proteins for proteolytic degradation using transfer-messenger RNA (tmRNA). This small stable RNA represents a hybrid of tRNA- and mRNA-like domains connected by a variable number of pseudoknots. Comparative sequence analysis of tmRNAs found in bacteria, plastids, and mitochondria provides considerable insights into their secondary structures. Progress toward understanding the molecular mechanism of template switching, which constitutes an essential step in trans-translation, is hampered by our limited knowledge about the three-dimensional folding of tmRNA. To facilitate experimental testing of the molecular intricacies of trans-translation, which often require appropriately modified tmRNA derivatives, we developed a procedure for building three-dimensional models of tmRNA. Using comparative sequence analysis, phylogenetically-supported 2-D structures were obtained to serve as input for the program ERNA-3D. Motifs containing loops and turns were extracted from the known structures of other RNAs and used to improve the tmRNA models. Biologically feasible 3-D models for the entire tmRNA molecule could be obtained. The models were characterized by a functionally significant close proximity between the tRNA-like domain and the resume codon. Potential conformational changes which might lead to a more open structure of tmRNA upon binding to the ribosome are discussed. The method, described in detail for the tmRNAs of Escherichia coli, Bacillus anthracis, and Caulobacter crescentus, is applicable to every tmRNA. Improved molecular models of biological significance were obtained. These models will guide in the design of experiments and provide a better understanding of trans-translation. The comparative procedure described here for tmRNA is easily adopted for the modeling the members of other RNA families.
3-D physical models of mitosis (with asters) and cytokinesis.
Cheng, Kang; Zou, Changhua
2004-01-01
First, we define new concepts of Life Objects, Informative Objects and Virtual Objects, Discrete Chromosome Rings (DCR); we introduce a mathematical concept of meridian plane (MP) in a three dimensional (3-D) cylindrical coordinate system (CCS). Based on these concepts, classic mechanics, classic electromagnetism and published biological data, we develop our 3-D physical models of natural and normal mitosis (with asters) and cytokinesis, for animal cells in M phase. We propose following hypotheses: Chromosomes Exclusion: No normally and naturally replicated chromosomes can occupy the same nucleus without growing sizes of the nucleus and the cell. Spontaneous and strong electromagnetic fields (EMF) forces among chromosomes, centrosomes and microtubules split the nucleus and separate the two sets of sister chromatids when they are strong enough. Nuclei Exclusion: No normally and naturally doubled nuclei can occupy the same cell if the doubled size of nuclei is not far smaller than size of the cell. The spontaneous and strong EMF forces in protoplasm (or cortex), separate two sets of chromosomes, spindles and poles, drive contractile proteins to the equator in cell cortex, and continue to guide and to transport free charged objects until complete the cytokinesis. Centrioles Exclusion: No naturally and normally doubled centrioles can occupy the same centrosome. The spontaneous and strong repulsive EMF forces are the primary cause for the exclusions. The principles of our models are also applied to mitosis and cytokinesis for lower plant cells, to that of multiple nuclei or mutant chromosomes, and to meiosis, for both animal cells and lower plant cells.
3D vadose zone modeling using geostatistical inferences
Knutson, C.F.; Lee, C.B.
1991-01-01
In developing a 3D model of the 600 ft thick interbedded basalt and sediment complex that constitutes the vadose zone at the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering Laboratory (INEL) geostatistical data were captured for 12--15 parameters (e.g. permeability, porosity, saturation, etc. and flow height, flow width, flow internal zonation, etc.). This two scale data set was generated from studies of subsurface core and geophysical log suites at RWMC and from surface outcrop exposures located at the Box Canyon of the Big Lost River and from Hell's Half Acre lava field all located in the general RWMC area. Based on these currently available data, it is possible to build a 3D stochastic model that utilizes: cumulative distribution functions obtained from the geostatistical data; backstripping and rebuilding of stratigraphic units; an expert'' system that incorporates rules based on expert geologic analysis and experimentally derived geostatistics for providing: (a) a structural and isopach map of each layer, (b) a realization of the flow geometry of each basalt flow unit, and (c) a realization of the internal flow parameters (eg permeability, porosity, and saturation) for each flow. 10 refs., 4 figs., 1 tab.
High-resolution 3D digital models of artworks
NASA Astrophysics Data System (ADS)
Fontana, Raffaella; Gambino, Maria Chiara; Greco, Marinella; Pampaloni, Enrico; Pezzati, Luca; Scopigno, Roberto
2003-10-01
The measurement of the shape of an artwork usually requires a high-resolution instrumentation, in order to catch small details such as chisel marks, sculptural relieves, surface cracks, etc. 3D scanning techniques, together with new modeling software tools, allow a high fidelity reproduction of an artwork: these can be applied either to support and document its repair or for the realization of 3D archives and virtual museums. Starting from a high-resolution digital model of an object, a further step could be its reproduction by means of fast-prototyping techniques like stereo-lithography or electro-erosion. This work is aimed at showing the performance of a high-resolution laser scanner devoted to Cultural Heritage applications. The device is portable and very versatile, in order to allow in situ applications, accurate and reliable, so to capture intricate details. This laser profilometer has been used in a few surveys, the most significant of which are the monitoring the various phases of the restoration process of an ellenistic bronze (the Minerva of Arezzo, Florence), the cataloguing of some archaeological findings (from the Grotta della Poesia, Lecce) and the documenting of wooden panels surface conditions (the "Madonna del Cardellino" by Raffaello and "La Tebaide" by Beato Angelico).
In Silico 3D Modeling of Binding Activities.
Moro, Stefano; Sturlese, Mattia; Ciancetta, Antonella; Floris, Matteo
2016-01-01
In silico three-dimensional (3D) molecular modeling tools based upon the receptor/enzyme-ligand docking simulation in protein crystal structures and/or homology modeling of receptors have been reliably used in pharmacological research and development for decades. Molecular docking methodologies are helpful for revealing facets of activation and inactivation, thus improving mechanistic understanding and predicting molecular ligand binding activity, and they can have a high level of accuracy, and have also been explored and applied in chemical risk assessment. This computational approach is, however, only applicable for chemical hazard identification situations where the specific target receptor for a given chemical is known and the crystal structure/homology model of the receptor is available.
Stochastic Modeling of Calcium in 3D Geometry
Mazel, Tomáš; Raymond, Rebecca; Raymond-Stintz, Mary; Jett, Stephen; Wilson, Bridget S.
2009-01-01
Release of inflammatory mediators by mast cells in type 1 immediate-hypersensitivity allergic reactions relies on antigen-dependent increases in cytosolic calcium. Here, we used a series of electron microscopy images to build a 3D reconstruction representing a slice through a rat tumor mast cell, which then served as a basis for stochastic modeling of inositol-trisphosphate-mediated calcium responses. The stochastic approach was verified by reaction-diffusion modeling within the same geometry. Local proximity of the endoplasmic reticulum to either the plasma membrane or mitochondria is predicted to differentially impact local inositol trisphosphate receptor transport. The explicit consideration of organelle spatial relationships represents an important step toward building a comprehensive, realistic model of cellular calcium dynamics. PMID:19254531
Dynamic deformable models for 3D MRI heart segmentation
NASA Astrophysics Data System (ADS)
Zhukov, Leonid; Bao, Zhaosheng; Gusikov, Igor; Wood, John; Breen, David E.
2002-05-01
Automated or semiautomated segmentation of medical images decreases interstudy variation, observer bias, and postprocessing time as well as providing clincally-relevant quantitative data. In this paper we present a new dynamic deformable modeling approach to 3D segmentation. It utilizes recently developed dynamic remeshing techniques and curvature estimation methods to produce high-quality meshes. The approach has been implemented in an interactive environment that allows a user to specify an initial model and identify key features in the data. These features act as hard constraints that the model must not pass through as it deforms. We have employed the method to perform semi-automatic segmentation of heart structures from cine MRI data.
A simple dynamic wake model for time dependent wind turbine yaw
NASA Astrophysics Data System (ADS)
Shapiro, Carl; Meneveau, Charles; Gayme, Dennice
2016-11-01
This work develops a time dependent wake model for wind farms that better captures the spanwise and streamwise propagation of fluctuations generated by changes in turbine thrust and yaw angle. The model builds on classic wake models by incorporating time dependence and turbine yawing. These extensions enable us to capture the spanwise skewness in the yawed turbine wake as well as the dynamic advection of the wake downstream. This model is then compared to large eddy simulations of a wind farm with upstream rows of wind turbines dynamically yawing their rotors. An important advantage of the model is it allows us to take advantage of predictions of dynamic flow phenomena to coordinate the action of individual wind turbines for farm level control. We use the model to further explore the potential of wind farms to use wind turbine yaw to provide important services to the power grid through power tracking. This work is supported by NSF (SEP-1230788 and OISE-1243482, the WINDINSPIRE project).
NASA Astrophysics Data System (ADS)
Weng, Meng-Chia
2014-07-01
Based on the concept of generalized plasticity, this study proposes a constitutive model to describe the time-dependent behavior and wetting deterioration of sandstone. The proposed model (1) exhibits nonlinear elasticity under hydrostatic and shear loading, (2) follows the associated flow rule for viscoplastic deformation, (3) adopts a creep modulus that varies with the stress ratio, (4) considers the primary and secondary creep behaviors of rock, and (5) considers the effect of wetting deterioration. This model requires 13 material parameters, comprising 3 for elasticity, 7 for plasticity, and 3 for creep. All parameters can be determined easily by following the suggested procedures. The proposed model is first validated by comparison with triaxial tests of sandstone under different hydrostatic stress and cyclic loading conditions. In addition, the model is versatile in simulating time-dependent behavior through a series of multistage creep tests. Finally, to consider the effects of wetting deterioration, triaxial and creep tests under dry and water-saturated conditions are simulated. Comparison of the simulated and experimental data shows that the proposed model can predict the behavior of sandstone in dry and saturated conditions.
Relaxation-time measurement via a time-dependent helicity balance model
Wrobel, J. S.; Hansen, C. J.; Jarboe, T. R.; Smith, R. J.; Hossack, A. C.; Nelson, B. A.; Marklin, G. J.; Ennis, D. A.; Akcay, C.; Victor, B. S.
2013-01-15
A time-dependent helicity balance model applied to a spheromak helicity-injection experiment enables the measurement of the relaxation time during the sustainment phase of the spheromak. The experiment, the Helicity Injected Torus with Steady Inductive helicity injection (HIT-SI), studies spheromak formation and sustainment through inductive helicity injection. The model captures the dominant plasma behavior seen during helicity injection in HIT-SI by using an empirical helicity-decay rate, a time-dependent helicity-injection rate, and a composite Taylor state to model both the helicity content of the system and to calculate the resulting spheromak current. During single-injector operations, both the amplitude and the phase of the periodic rise and fall of the toroidal current are predicted by this model, with an exchange of helicity between the injector states and the spheromak state proposed as the causal mechanism. This phenomenon allows for the comparison of the delay between the current rises in the experiment and the numerical model, enabling a measurement of the relaxation time. The measured relaxation time of 4.8 {mu}s {+-} 2.8 {mu}s is shorter than the toroidal Alfven timescale. These results validate Hall MHD calculations of the Geospace Environmental Modeling challenge.
Milestone report: Status report on time-dependent modeling for current profile feedback control
Casper, T.A.; Crotinger, J.; Haney, S.
1995-09-29
During the past year, LLNL efforts in the DIII-D experimental program have expanded to include time-dependent modeling of advanced tokamak (AT) operating modes. Consistent with our involvement in experimental operations, we have directed our initial efforts at modeling the negative central shear (NCS) configuration, an important and attractive mode of operation for reducing the size and cost of future tokamak experiments without sacrificing performance. In this endeavor, we have brought into use the Corsica modeling code as a tool for investigating the time-dependent evolution and control of various operating modes. In our current efforts, we are contributing to the analysis of the NCS experimental data using analysis tools such as the EFIT equilibrium code and the ONETWO and TRANSP transport codes. Results of these analyses are being used for comparisons with the Corsica modeling. Future directions include the modeling of startup and sustaining of NCS (and other AT) configurations, the understanding of current drive effects, the development of current drive scenarios and control algorithms, and the design of experiments and prediction of experimental results. We are currently in the early stages of applying this powerful modeling tool to the DIII-D experimental program.
Topological order in an exactly solvable 3D spin model
Bravyi, Sergey; Leemhuis, Bernhard; Terhal, Barbara M.
2011-04-15
Research highlights: RHtriangle We study exactly solvable spin model with six-qubit nearest neighbor interactions on a 3D face centered cubic lattice. RHtriangle The ground space of the model exhibits topological quantum order. RHtriangle Elementary excitations can be geometrically described as the corners of rectangular-shaped membranes. RHtriangle The ground space can encode 4g qubits where g is the greatest common divisor of the lattice dimensions. RHtriangle Logical operators acting on the encoded qubits are described in terms of closed strings and closed membranes. - Abstract: We study a 3D generalization of the toric code model introduced recently by Chamon. This is an exactly solvable spin model with six-qubit nearest-neighbor interactions on an FCC lattice whose ground space exhibits topological quantum order. The elementary excitations of this model which we call monopoles can be geometrically described as the corners of rectangular-shaped membranes. We prove that the creation of an isolated monopole separated from other monopoles by a distance R requires an operator acting on {Omega}(R{sup 2}) qubits. Composite particles that consist of two monopoles (dipoles) and four monopoles (quadrupoles) can be described as end-points of strings. The peculiar feature of the model is that dipole-type strings are rigid, that is, such strings must be aligned with face-diagonals of the lattice. For periodic boundary conditions the ground space can encode 4g qubits where g is the greatest common divisor of the lattice dimensions. We describe a complete set of logical operators acting on the encoded qubits in terms of closed strings and closed membranes.
Development of an aquifer management model AQMAN3D
Puig, Juan Carlos; Rolon-Collazo, L. I.; Pagan-Trinidad, Ishmael; Krishna, J.H.; Quinones-Aponte, Vicente; Gomez-Gomez, Fernando; Morris, G.L.
1990-01-01
A computer code that enables the use of the USGS Modular groundwater flow model for aquifermanagement modeling has been developed. Aquifermanagement techniques integrate groundwater flow modeling with linear quadratic optimization methods for the solution of various aquifer management problems. The model AQMAN3D, is a modified version of a previously developed two-dimensional AQMAN model. The idea of coupling the AQMAN model with the MODULAR model arose because actual groundwater flow systems behave in a three dimensional manner, therefore requiring treatment as such, and due to the widespread use of MODULAR. The use of the AQMAN3D model permits the implementation of the technique known as aquifer managementmodeling. A generalized approach to obtain an optimal solution to an aquifer management problem is proposed, and a sample test problem is presented to illustrate the use of the model. Even though the model provides the hydrologist with a new and powerful investigative tool, its applicability is limited to confined or quasiconfined systems.
NASA Astrophysics Data System (ADS)
Fossati, Giovanni
This proposal aims at fully exploiting the large body of X-ray and multiwavelength observational data on TeV gamma-ray bright blazars for a detailed comparison with state- of-the art blazar radiation transfer simulations. The aim of this investigation is to develop diagnostics on critical jet parameters and shock physics, such as the magnetic field, the kinetic energy content in the jets, the characteristics of the shock acceleration mechanisms, and the detailed influence on geometry on the observed spectral variability features. Our project will comprises a systematic, uniform re-analysis of the relevant (in particular, X-ray) data sets. We will extract time-dependent spectral energy distributions, light curves, and intra-band as well as inter-band time lags from the available data. The modeling tasks will start with a quick sweep through parameter space using a semi- analytical internal-shock model. This will help to narrow down parameters such as the Lorentz factors of interacting emission regions, the overall energy requirements, the characteristics of the electron distributions accelerated at internal shocks, and the magnetic field. The parameters of this semi-analytical internal-shock model that allow for a representation of time-dependent SEDs, light curves and inter-band time lags, will form the starting point for our detailed modeling using our state-of-the-art time-dependent multi-zone Monte-Carlo simulation code. Using that code, we will explore in more detail the characteristics of the particle acceleration in active regions and the influence of various geometries on the observable features. By capitalizing on archival data of several NASA space astrophysics missions our proposal is in agreement with the NASA ADAP research objective, "the analysis io NASA space astrophysics data that are archived in the public domain at the time of submission", as stated in the NASA Research announcement.
A population pharmacokinetic model with time-dependent covariates measured with errors.
Li, Lang; Lin, Xihong; Brown, Morton B; Gupta, Suneel; Lee, Kyung-Hoon
2004-06-01
We propose a population pharmacokinetic (PK) model with time-dependent covariates measured with errors. This model is used to model S-oxybutynin's kinetics following an oral administration of Ditropan, and allows the distribution rate to depend on time-dependent covariates blood pressure and heart rate, which are measured with errors. We propose two two-step estimation methods: the second-order two-step method with numerical solutions of differential equations (2orderND), and the second-order two-step method with closed form approximate solutions of differential equations (2orderAD). The proposed methods are computationally easy and require fitting a linear mixed model at the first step and a nonlinear mixed model at the second step. We apply the proposed methods to the analysis of the Ditropan data, and evaluate their performance using a simulation study. Our results show that the 2orderND method performs well, while the 2orderAD method can yield PK parameter estimators that are subject to considerable biases.
NASA Technical Reports Server (NTRS)
Saleeb, A. F.; Arnold, Steven M.
2001-01-01
Since most advanced material systems (for example metallic-, polymer-, and ceramic-based systems) being currently researched and evaluated are for high-temperature airframe and propulsion system applications, the required constitutive models must account for both reversible and irreversible time-dependent deformations. Furthermore, since an integral part of continuum-based computational methodologies (be they microscale- or macroscale-based) is an accurate and computationally efficient constitutive model to describe the deformation behavior of the materials of interest, extensive research efforts have been made over the years on the phenomenological representations of constitutive material behavior in the inelastic analysis of structures. From a more recent and comprehensive perspective, the NASA Glenn Research Center in conjunction with the University of Akron has emphasized concurrently addressing three important and related areas: that is, 1) Mathematical formulation; 2) Algorithmic developments for updating (integrating) the external (e.g., stress) and internal state variables; 3) Parameter estimation for characterizing the model. This concurrent perspective to constitutive modeling has enabled the overcoming of the two major obstacles to fully utilizing these sophisticated time-dependent (hereditary) constitutive models in practical engineering analysis. These obstacles are: 1) Lack of efficient and robust integration algorithms; 2) Difficulties associated with characterizing the large number of required material parameters, particularly when many of these parameters lack obvious or direct physical interpretations.
Geomorphological maps and 3d models in cave research
NASA Astrophysics Data System (ADS)
Ballesteros, Daniel; Jiménez-Sánchez, Montserrat; José Domínguez-Cuesta, María
2013-04-01
Cave geomorphological processes and features can be studied by geomorphological maps although topographic maps, aerial photos and GPS are not available. Methods in cave geomorphological mapping are conditioned by cave environment configuration, the need of using speleological techniques, and limitations arising from the projection of the 3D data from the cave to a 2D plan. Some of our previous works in the Cantabrian Mountains and Cantabrian Coast (NW Spain) established the approach of the design of cave geomorphological maps and its legend. Today we are improving the display of cave process combining geomorphological maps and 3d models based on the experience obtained from the research of one cave from the Cantabrian Coast and four caves in the Picos de Europa National Park (funded by GEOCAVE project, Spanish National Parks Agency). The five caves are developed in Carboniferous limestone affected by faults and thrusts. The method of work includes: 1) the elaboration of the cave survey at 1:50 to 1:500 scale; 2) the check of the cave survey of three caves by closed loops; 3) the mapping of cave features based on the performed survey; 4) the 3d modeling of the caves approximating each survey shoot by an octagonal prism; and 5) the implementation and management of the survey and geomorphological map in a Geographic Information System. Based on the survey, the cavities are small caves to deep alpine shafts with 281 to 4,438 m length and up to 738 m deep. The precision of the cave maps only could be estimated in two caves at a cavity scale, displaying both of them a 2.49 % error. The prisms of the 3d model was classified into four groups according to the morphology of the cave passage: 1) canyons, 2) phreatic and epiphreatic tubes, 3) soutirage conduits, 4) mixed forms composed by phreatic and epiphreatic tubes modified by fluvial incision, 5) pitches and 6) irregular passages enlarged strongly by gravity process. According to our previous works geomorphological
Geographic Video 3d Data Model And Retrieval
NASA Astrophysics Data System (ADS)
Han, Z.; Cui, C.; Kong, Y.; Wu, H.
2014-04-01
Geographic video includes both spatial and temporal geographic features acquired through ground-based or non-ground-based cameras. With the popularity of video capture devices such as smartphones, the volume of user-generated geographic video clips has grown significantly and the trend of this growth is quickly accelerating. Such a massive and increasing volume poses a major challenge to efficient video management and query. Most of the today's video management and query techniques are based on signal level content extraction. They are not able to fully utilize the geographic information of the videos. This paper aimed to introduce a geographic video 3D data model based on spatial information. The main idea of the model is to utilize the location, trajectory and azimuth information acquired by sensors such as GPS receivers and 3D electronic compasses in conjunction with video contents. The raw spatial information is synthesized to point, line, polygon and solid according to the camcorder parameters such as focal length and angle of view. With the video segment and video frame, we defined the three categories geometry object using the geometry model of OGC Simple Features Specification for SQL. We can query video through computing the spatial relation between query objects and three categories geometry object such as VFLocation, VSTrajectory, VSFOView and VFFovCone etc. We designed the query methods using the structured query language (SQL) in detail. The experiment indicate that the model is a multiple objective, integration, loosely coupled, flexible and extensible data model for the management of geographic stereo video.
Measurement of Laser Weld Temperatures for 3D Model Input
Dagel, Daryl; Grossetete, Grant; Maccallum, Danny O.
2016-10-01
Laser welding is a key joining process used extensively in the manufacture and assembly of critical components for several weapons systems. Sandia National Laboratories advances the understanding of the laser welding process through coupled experimentation and modeling. This report summarizes the experimental portion of the research program, which focused on measuring temperatures and thermal history of laser welds on steel plates. To increase confidence in measurement accuracy, researchers utilized multiple complementary techniques to acquire temperatures during laser welding. This data serves as input to and validation of 3D laser welding models aimed at predicting microstructure and the formation of defects and their impact on weld-joint reliability, a crucial step in rapid prototyping of weapons components.
3D Tissue-Engineered Model of Ewing Sarcoma
Lamhamedi-Cherradi, Salah-Eddine; Santoro, Marco; Ramammoorthy, Vandhana; Menegaz, Brian A.; Bartholomeusz, Geoffrey; Iles, Lakesla R.; Amin, Hesham M.; Livingston, Andrew J.; Mikos, Antonios G.; Ludwig, Joseph A.
2015-01-01
Despite longstanding reliance upon monolayer culture for studying cancer cells, and numerous advantages from both a practical and experimental standpoint, a growing body of evidence suggests more complex three-dimensional (3D) models are necessary to properly mimic many of the critical hallmarks associated with the oncogenesis, maintenance and spread of Ewing sarcoma (ES), the second most common pediatric bone tumor. And as clinicians increasingly turn to biologically-targeted therapies that exert their effects not only on the tumor cells themselves, but also on the surrounding extracellular matrix, it is especially important that preclinical models evolve in parallel to reliably measure antineoplastic effects and possible mechanisms of de novo and acquired drug resistance. Herein, we highlight a number of innovative methods used to fabricate biomimetic ES tumors, encompassing both the surrounding cellular milieu and extracellular matrix (ECM), and suggest potential applications to advance our understanding of ES biology, preclinical drug testing, and personalized medicine. PMID:25109853
3D Model of the Eta Carinae Little Homunculus Nebula
NASA Astrophysics Data System (ADS)
Steffen, Wolfgang; Teodoro, Mairan; Madura, Thomas; Groh, Jose H.; Gull, Theodore R.; Corcoran, Michael F.; Damineli, Augusto; Hamaguchi, Kenji
2015-01-01
We extend our morpho-kinematic 3D modeling of the Homunculus nebula (Steffen et al., 2014) to the interior nested Little Homunculus. The model is based on spectroscopic observations from HST/STIS. We find that the structure of the interior Little Homunculus is rather flat in the polar regions and interacts with the main Homunculus nebula only on one side, towards the periastron direction of the binary orbit. Furthermore, the two lobes of the LH are misaligned, also towards the periastron direction. As an explanation for the misalignment we propose that, in both cases, shortly after the eruptions that created the bipolar nebulae from the primary star, the off-center wind of the secondary has pushed the ejecta towards the periastron directions, since the secondary is most of the time near the apastron. Future hydrodynamic simulations are warranted to confirm this scenario.
Modeling tree crown dynamics with 3D partial differential equations
Beyer, Robert; Letort, Véronique; Cournède, Paul-Henry
2014-01-01
We characterize a tree's spatial foliage distribution by the local leaf area density. Considering this spatially continuous variable allows to describe the spatiotemporal evolution of the tree crown by means of 3D partial differential equations. These offer a framework to rigorously take locally and adaptively acting effects into account, notably the growth toward light. Biomass production through photosynthesis and the allocation to foliage and wood are readily included in this model framework. The system of equations stands out due to its inherent dynamic property of self-organization and spontaneous adaptation, generating complex behavior from even only a few parameters. The density-based approach yields spatially structured tree crowns without relying on detailed geometry. We present the methodological fundamentals of such a modeling approach and discuss further prospects and applications. PMID:25101095
3D in vitro modeling of the central nervous system.
Hopkins, Amy M; DeSimone, Elise; Chwalek, Karolina; Kaplan, David L
2015-02-01
There are currently more than 600 diseases characterized as affecting the central nervous system (CNS) which inflict neural damage. Unfortunately, few of these conditions have effective treatments available. Although significant efforts have been put into developing new therapeutics, drugs which were promising in the developmental phase have high attrition rates in late stage clinical trials. These failures could be circumvented if current 2D in vitro and in vivo models were improved. 3D, tissue-engineered in vitro systems can address this need and enhance clinical translation through two approaches: (1) bottom-up, and (2) top-down (developmental/regenerative) strategies to reproduce the structure and function of human tissues. Critical challenges remain including biomaterials capable of matching the mechanical properties and extracellular matrix (ECM) composition of neural tissues, compartmentalized scaffolds that support heterogeneous tissue architectures reflective of brain organization and structure, and robust functional assays for in vitro tissue validation. The unique design parameters defined by the complex physiology of the CNS for construction and validation of 3D in vitro neural systems are reviewed here.
3D in vitro modeling of the central nervous system
Hopkins, Amy M.; DeSimone, Elise; Chwalek, Karolina; Kaplan, David L.
2015-01-01
There are currently more than 600 diseases characterized as affecting the central nervous system (CNS) which inflict neural damage. Unfortunately, few of these conditions have effective treatments available. Although significant efforts have been put into developing new therapeutics, drugs which were promising in the developmental phase have high attrition rates in late stage clinical trials. These failures could be circumvented if current 2D in vitro and in vivo models were improved. 3D, tissue-engineered in vitro systems can address this need and enhance clinical translation through two approaches: (1) bottom-up, and (2) top-down (developmental/regenerative) strategies to reproduce the structure and function of human tissues. Critical challenges remain including biomaterials capable of matching the mechanical properties and extracellular matrix (ECM) composition of neural tissues, compartmentalized scaffolds that support heterogeneous tissue architectures reflective of brain organization and structure, and robust functional assays for in vitro tissue validation. The unique design parameters defined by the complex physiology of the CNS for construction and validation of 3D in vitro neural systems are reviewed here. PMID:25461688
Gene3D: modelling protein structure, function and evolution.
Yeats, Corin; Maibaum, Michael; Marsden, Russell; Dibley, Mark; Lee, David; Addou, Sarah; Orengo, Christine A
2006-01-01
The Gene3D release 4 database and web portal (http://cathwww.biochem.ucl.ac.uk:8080/Gene3D) provide a combined structural, functional and evolutionary view of the protein world. It is focussed on providing structural annotation for protein sequences without structural representatives--including the complete proteome sets of over 240 different species. The protein sequences have also been clustered into whole-chain families so as to aid functional prediction. The structural annotation is generated using HMM models based on the CATH domain families; CATH is a repository for manually deduced protein domains. Amongst the changes from the last publication are: the addition of over 100 genomes and the UniProt sequence database, domain data from Pfam, metabolic pathway and functional data from COGs, KEGG and GO, and protein-protein interaction data from MINT and BIND. The website has been rebuilt to allow more sophisticated querying and the data returned is presented in a clearer format with greater functionality. Furthermore, all data can be downloaded in a simple XML format, allowing users to carry out complex investigations at their own computers.
Plasticized protein for 3D printing by fused deposition modeling
NASA Astrophysics Data System (ADS)
Chaunier, Laurent; Leroy, Eric; Della Valle, Guy; Lourdin, Denis
2016-10-01
The developments of Additive Manufacturing (AM) by Fused Deposition Modeling (FDM) now target new 3D printable materials, leading to novel properties like those given by biopolymers such as proteins: degradability, biocompatibility and edibility. Plasticized materials from zein, a storage protein issued from corn, present interesting thermomechanical and rheological properties, possibly matching with AM-FDM specifications. Thus commercial zein plasticized with 20% glycerol has a glass transition temperature (Tg) at about 42°C, after storage at intermediate relative humidity (RH=59%). Its principal mechanical relaxation at Tα ≈ 50°C leads to a drop of the elastic modulus from about 1.1 GPa, at ambient temperature, to 0.6 MPa at Tα+100°C. These values are in the same range as values obtained in the case of standard polymers for AM-FDM processing, as PLA and ABS, although relaxation mechanisms are likely different in these materials. Such results lead to the setting up of zein-based compositions printable by AM-FDM and allow processing bioresorbable printed parts, with designed 3D geometry and structure.
Modelling of image-catheter motion for 3-D IVUS.
Rosales, Misael; Radeva, Petia; Rodriguez-Leor, Oriol; Gil, Debora
2009-02-01
Three-dimensional intravascular ultrasound (IVUS) allows to visualize and obtain volumetric measurements of coronary lesions through an exploration of the cross sections and longitudinal views of arteries. However, the visualization and subsequent morpho-geometric measurements in IVUS longitudinal cuts are subject to distortion caused by periodic image/vessel motion around the IVUS catheter. Usually, to overcome the image motion artifact ECG-gating and image-gated approaches are proposed, leading to slowing the pullback acquisition or disregarding part of IVUS data. In this paper, we argue that the image motion is due to 3-D vessel geometry as well as cardiac dynamics, and propose a dynamic model based on the tracking of an elliptical vessel approximation to recover the rigid transformation and align IVUS images without loosing any IVUS data. We report an extensive validation with synthetic simulated data and in vivo IVUS sequences of 30 patients achieving an average reduction of the image artifact of 97% in synthetic data and 79% in real-data. Our study shows that IVUS alignment improves longitudinal analysis of the IVUS data and is a necessary step towards accurate reconstruction and volumetric measurements of 3-D IVUS.
Modeling approaches for ligand-based 3D similarity.
Tresadern, Gary; Bemporad, Daniele
2010-10-01
3D ligand-based similarity approaches are widely used in the early phases of drug discovery for tasks such as hit finding by virtual screening or compound design with quantitative structure-activity relationships. Here in we review widely used software for performing such tasks. Some techniques are based on relatively mature technology, shape-based similarity for instance. Typically, these methods remained in the realm of the expert user, the experienced modeler. However, advances in implementation and speed have improved usability and allow these methods to be applied to databases comprising millions of compounds. There are now many reports of such methods impacting drug-discovery projects. As such, the medicinal chemistry community has become the intended market for some of these new tools, yet they may consider the wide array and choice of approaches somewhat disconcerting. Each method has subtle differences and is better suited to certain tasks than others. In this article we review some of the widely used computational methods via application, provide straightforward background on the underlying theory and provide examples for the interested reader to pursue in more detail. In the new era of preclinical drug discovery there will be ever more pressure to move faster and more efficiently, and computational approaches based on 3D ligand similarity will play an increasing role in in this process.
Classification of transient behaviours in a time-dependent toggle switch model
2014-01-01
Background Waddington’s epigenetic landscape is an intuitive metaphor for the developmental and evolutionary potential of biological regulatory processes. It emphasises time-dependence and transient behaviour. Nowadays, we can derive this landscape by modelling a specific regulatory network as a dynamical system and calculating its so-called potential surface. In this sense, potential surfaces are the mathematical equivalent of the Waddingtonian landscape metaphor. In order to fully capture the time-dependent (non-autonomous) transient behaviour of biological processes, we must be able to characterise potential landscapes and how they change over time. However, currently available mathematical tools focus on the asymptotic (steady-state) behaviour of autonomous dynamical systems, which restricts how biological systems are studied. Results We present a pragmatic first step towards a methodology for dealing with transient behaviours in non-autonomous systems. We propose a classification scheme for different kinds of such dynamics based on the simulation of a simple genetic toggle-switch model with time-variable parameters. For this low-dimensional system, we can calculate and explicitly visualise numerical approximations to the potential landscape. Focussing on transient dynamics in non-autonomous systems reveals a range of interesting and biologically relevant behaviours that would be missed in steady-state analyses of autonomous systems. Our simulation-based approach allows us to identify four qualitatively different kinds of dynamics: transitions, pursuits, and two kinds of captures. We describe these in detail, and illustrate the usefulness of our classification scheme by providing a number of examples that demonstrate how it can be employed to gain specific mechanistic insights into the dynamics of gene regulation. Conclusions The practical aim of our proposed classification scheme is to make the analysis of explicitly time-dependent transient behaviour
Polygonal Shapes Detection in 3d Models of Complex Architectures
NASA Astrophysics Data System (ADS)
Benciolini, G. B.; Vitti, A.
2015-02-01
A sequential application of two global models defined on a variational framework is proposed for the detection of polygonal shapes in 3D models of complex architectures. As a first step, the procedure involves the use of the Mumford and Shah (1989) 1st-order variational model in dimension two (gridded height data are processed). In the Mumford-Shah model an auxiliary function detects the sharp changes, i.e., the discontinuities, of a piecewise smooth approximation of the data. The Mumford-Shah model requires the global minimization of a specific functional to simultaneously produce both the smooth approximation and its discontinuities. In the proposed procedure, the edges of the smooth approximation derived by a specific processing of the auxiliary function are then processed using the Blake and Zisserman (1987) 2nd-order variational model in dimension one (edges are processed in the plane). This second step permits to describe the edges of an object by means of piecewise almost-linear approximation of the input edges themselves and to detects sharp changes of the first-derivative of the edges so to detect corners. The Mumford-Shah variational model is used in two dimensions accepting the original data as primary input. The Blake-Zisserman variational model is used in one dimension for the refinement of the description of the edges. The selection among all the boundaries detected by the Mumford-Shah model of those that present a shape close to a polygon is performed by considering only those boundaries for which the Blake-Zisserman model identified discontinuities in their first derivative. The output of the procedure are hence shapes, coming from 3D geometric data, that can be considered as polygons. The application of the procedure is suitable for, but not limited to, the detection of objects such as foot-print of polygonal buildings, building facade boundaries or windows contours. v The procedure is applied to a height model of the building of the Engineering
Time dependence of recruitment and derecruitment in the lung: a theoretical model.
Bates, Jason H T; Irvin, Charles G
2002-08-01
Recruitment and derecruitment (R/D) of air spaces within the lung is greatly enhanced in lung injury and is thought to be responsible for exacerbating injury during mechanical ventilation. There is evidence to suggest that R/D is a time-dependent phenomenon. We have developed a computer model of the lung consisting of a parallel arrangement of airways and alveolar units. Each airway has a critical pressure (Pcrit) above which it tends to open and below which it tends to close but at a rate determined by how far pressure is from Pcrit. With an appropriate distribution of Pcrit and R/D velocity characteristics, the model able to produce realistic first and second pressure-volume curves of a lung inflated from an initially degassed state. The model also predicts that lung elastance will increase transiently after a deep inflation to a degree that increases as lung volume decreases and as the lung becomes injured. We conclude that our model captures the time-dependent mechanical behavior of the lung due to gradual R/D of lung units.
Advanced prior modeling for 3D bright field electron tomography
NASA Astrophysics Data System (ADS)
Sreehari, Suhas; Venkatakrishnan, S. V.; Drummy, Lawrence F.; Simmons, Jeffrey P.; Bouman, Charles A.
2015-03-01
Many important imaging problems in material science involve reconstruction of images containing repetitive non-local structures. Model-based iterative reconstruction (MBIR) could in principle exploit such redundancies through the selection of a log prior probability term. However, in practice, determining such a log prior term that accounts for the similarity between distant structures in the image is quite challenging. Much progress has been made in the development of denoising algorithms like non-local means and BM3D, and these are known to successfully capture non-local redundancies in images. But the fact that these denoising operations are not explicitly formulated as cost functions makes it unclear as to how to incorporate them in the MBIR framework. In this paper, we formulate a solution to bright field electron tomography by augmenting the existing bright field MBIR method to incorporate any non-local denoising operator as a prior model. We accomplish this using a framework we call plug-and-play priors that decouples the log likelihood and the log prior probability terms in the MBIR cost function. We specifically use 3D non-local means (NLM) as the prior model in the plug-and-play framework, and showcase high quality tomographic reconstructions of a simulated aluminum spheres dataset, and two real datasets of aluminum spheres and ferritin structures. We observe that streak and smear artifacts are visibly suppressed, and that edges are preserved. Also, we report lower RMSE values compared to the conventional MBIR reconstruction using qGGMRF as the prior model.
Time-dependent Ginzburg-Landau model for nonfrustrated linear ABC triblock terpolymers.
Millett, Paul C
2015-08-01
A time-dependent Ginzburg-Landau (TDGL) model is proposed to simulate the ordering of linear ABC triblock terpolymers. The model, in its current form, is applicable to nonfrustrated triblock systems, with the specific condition that χAC≫χAB≈χBC. Simulations are presented that demonstrate the model's ability to evolve a wide variety of morphologies throughout time, including tetragonal, core-shell hexagonal, three-phase lamellar, and beads-in-lamellar phases. The model also incorporates an interaction term to study templated substrates for directed self-assembly. The efficiency of the TDGL model enables large-scale simulations that allow investigation of self-assembly, and directed self-assembly, processes that may exhibit very small defect concentrations.
One-dimensional time-dependent debris bed model. [PWR; BWR
Gorham-Bergeron, E.
1982-01-01
The dryout process is described for a particle bed using a time-dependent one-dimensional porous bed model. The model is based on momentum, energy and mass conservation equations for separated flow. The model is applicable to the case in which capillary forces can be neglected. For the case in which only laminar flow is considered exact algebraic solutions to the equations can be obtained. These are presented. Distinct regimes for the parameterized solutions can be identified and associated with moving fronts in the bed. Extension to the full turbulent and laminar equations is made with the aid of insights gained from solution of the laminar case. Comparison with recent experimental results and theoretical predictions is made. The model is seen to encompass and extend the theoretical models. It suggests additional experiments.
Time-dependent Ginzburg-Landau model for nonfrustrated linear A B C triblock terpolymers
NASA Astrophysics Data System (ADS)
Millett, Paul C.
2015-08-01
A time-dependent Ginzburg-Landau (TDGL) model is proposed to simulate the ordering of linear A B C triblock terpolymers. The model, in its current form, is applicable to nonfrustrated triblock systems, with the specific condition that χA C≫χA B≈χB C . Simulations are presented that demonstrate the model's ability to evolve a wide variety of morphologies throughout time, including tetragonal, core-shell hexagonal, three-phase lamellar, and beads-in-lamellar phases. The model also incorporates an interaction term to study templated substrates for directed self-assembly. The efficiency of the TDGL model enables large-scale simulations that allow investigation of self-assembly, and directed self-assembly, processes that may exhibit very small defect concentrations.
Time-Dependent Model for Fluid Flow in Porous Materials with Multiple Pore Sizes.
Cummins, Brian M; Chinthapatla, Rukesh; Ligler, Frances S; Walker, Glenn M
2017-04-18
An understanding of fluid transport through porous materials is critical for the development of lateral flow assays and analytical devices based on paper microfluidics. Models of fluid transport within porous materials often assume a single capillary pressure and permeability value for the material, implying that the material comprises a single pore size and that the porous material is fully saturated behind the visible wetted front. As a result, current models can lead to inaccuracies when modeling transport over long distances and/or times. A new transport model is presented that incorporates a range of pore sizes to more accurately predict the capillary transport of fluid in porous materials. The model effectively predicts the time-dependent saturation of rectangular strips of Whatman filter no. 1 paper using the manufacturer's data, published pore-size distribution measurements, and the fluid's properties.
Proposed SPAR Modeling Method for Quantifying Time Dependent Station Blackout Cut Sets
John A. Schroeder
2010-06-01
Abstract: The U.S. Nuclear Regulatory Commission’s (USNRC’s) Standardized Plant Analysis Risk (SPAR) models and industry risk models take similar approaches to analyzing the risk associated with loss of offsite power and station blackout (LOOP/SBO) events at nuclear reactor plants. In both SPAR models and industry models, core damage risk resulting from a LOOP/SBO event is analyzed using a combination of event trees and fault trees that produce cut sets that are, in turn, quantified to obtain a numerical estimate of the resulting core damage risk. A proposed SPAR method for quantifying the time-dependent cut sets is sometimes referred to as a convolution method. The SPAR method reflects assumptions about the timing of emergency diesel failures, the timing of subsequent attempts at emergency diesel repair, and the timing of core damage that may be different than those often used in industry models. This paper describes the proposed SPAR method.
Adaptive Network Dynamics - Modeling and Control of Time-Dependent Social Contacts
Schwartz, Ira B.; Shaw, Leah B.; Shkarayev, Maxim S.
2013-01-01
Real networks consisting of social contacts do not possess static connections. That is, social connections may be time dependent due to a variety of individual behavioral decisions based on current network connections. Examples of adaptive networks occur in epidemics, where information about infectious individuals may change the rewiring of healthy people, or in the recruitment of individuals to a cause or fad, where rewiring may optimize recruitment of susceptible individuals. In this paper, we will review some of the dynamical properties of adaptive networks, and show how they predict novel phenomena as well as yield insight into new controls. The applications will be control of epidemic outbreaks and terrorist recruitment modeling. PMID:25414913
NASA Astrophysics Data System (ADS)
Mahmood, T.; Shahzad, A.; Iqbal, Z.; Ahmed, J.; Khan, M.
A study is presented for the flow and heat transfer of Sisko fluid model over an unsteady stretching sheet in the presence of uniform magnetic field. While taking newly developed similarity transformations, the governing time dependent partial differential equations are reduced to nonlinear ordinary differential equations. Numerical solutions of the reduced nonlinear differential equations are found by employing Shooting method. The influence of physical parameters of interest on the velocity and temperature profiles are highlighted graphically and examined in detail. Moreover, the skin friction coefficient and Nusselt number are tabulated against influential parameters. Skin friction coefficient increases with unsteadiness parameter, magnetic field and suction parameter.
A new kinetic model for time-dependent polar plasma outflow - Initial results
NASA Technical Reports Server (NTRS)
Wilson, G. R.; Ho, C. W.; Horwitz, J. L.; Singh, N.; Moore, T. E.
1990-01-01
A new time-dependent kinetic plasma outflow model has been developed, which uses a kinetic description of the parallel motions of the ion guiding centers, while assuming the electrons are a massless neutralizing fluid. The ions, O(+) and H(+) are followed as individual particles which respond to the gravitational, magnetic mirror and ambipolar electric forces as they move in one dimension along a magnetic flux tube. Results are presented for a case where the electron temperature in the flux tube is raised from a value near the ion temperature (3000 K) to a value of 10,000 K.
Experimental evaluation criteria for constitutive models of time dependent cyclic plasticity
NASA Technical Reports Server (NTRS)
Martin, J. F.
1986-01-01
Notched members were tested at temperatures far above those recorded till now. Simulation of the notch root stress response was accomplished to establish notch stress-strain behavior. Cyclic stress-strain profiles across the net-section were recorded and on-line direct notch strain control was accomplished. Data are compared to three analysis techniques with good results. The objective of the study is to generate experimental data that can be used to evaluate the accuracy of constitutive models of time dependent cyclic plasticity.
Ma, Nina K L; Lim, Jia Kai; Leong, Meng Fatt; Sandanaraj, Edwin; Ang, Beng Ti; Tang, Carol; Wan, Andrew C A
2016-02-01
A hierarchy of cellular stemness exists in certain cancers, and any successful strategy to treat such cancers would have to eliminate the self-renewing tumor-initiating cells at the apex of the hierarchy. The cellular microenvironment, in particular the extracellular matrix (ECM), is believed to have a role in regulating stemness. In this work, U251 glioblastoma cells are cultured on electrospun polystyrene (ESPS) scaffolds coated with an array of 7 laminin isoforms to provide a 3D model for stem cell-related genes and proteins expression studies. We observed collaboration between 3D context and laminins in promoting glioma stemness. Depending on the laminin isoform presented, U251 cells cultured on ESPS scaffolds (3D) exhibited increased expression of stemness markers compared to those cultured on tissue culture polystyrene (2D). Our results indicate the influence of 3D (versus 2D) context on integrin expression, specifically, the upregulation of the laminin-binding integrins alpha 6 and beta 4. By a colony forming assay, we showed enhanced clonogenicity of cells grown on ESPS scaffolds in collaboration with laminins 411, 421, 511 and 521. Evaluation of patient glioma databases demonstrated significant enrichment of integrin and ECM pathway networks in tumors of worse prognosis, consistent with our observations. The present results demonstrate how 3D versus 2D context profoundly affects ECM signaling, leading to stemness. Copyright © 2015 Elsevier Ltd. All rights reserved.
Modeling the time-dependent flexural response of wood-plastic composite materials
NASA Astrophysics Data System (ADS)
Hamel, Scott E.
Wood-plastic composites (WPCs) are moisture sensitive bimodal anisotropic nonlinear viscoelastic materials, with time and temperature having the greatest effect on mechanical behavior. As WPC producers seek to manufacture structural bending members, such as beams and joists, it is important that the material's time and temperature-dependent mechanical behavior be understood and characterized. The complicated time-dependent behavior means that WPC bending deflections cannot be adequately predicted for even practical design purposes using simple linear-elastic models. Instead, mechanics-based models that incorporate the observed time-dependent and nonlinear responses are necessary. This dissertation presents an experimental and modeling program used to test and characterize the axial and shear behaviors of seven different WPC products (primarily polyethylene and polypropylene) subjected to both quasi-static and creep loading at multiple temperatures. These data were used to develop a mechanics based model that can predict bending deflections of complex sections at any time or temperature. Additionally, a practical design method and standardized test procedures were created for use in typical long-term bending situations. A mechanical model for WPCs must combine time-dependent material characterization with a tool that can simulate mode dependence, temperature dependence, changing neutral axis location, and nonlinear axial stress distributions that vary over the length of a member and evolve with time. Finite-element (FE) modeling was chosen as the most practical way to satisfy these requirements. The model developed in this study uses an FE model with a custom-designed material model. Bending deflection predictions from the model were compared to experimental testing and the model showed some success despite the difficulties created by the material variability. The practical method created for designing WPC structural bending members utilizes four material constants
Alcan, Toros; Ceylanoğlu, Cenk; Baysal, Bekir
2009-01-01
To investigate the effects of different storage periods of alginate impressions on digital model accuracy. A total of 105 impressions were taken from a master model with three different brands of alginates and were poured into stone models in five different storage periods. In all, 21 stone models were poured and immediately were scanned, and 21 digital models were prepared. The remaining 84 impressions were poured after 1, 2, 3, and 4 days, respectively. Five linear measurements were made by three researchers on the master model, the stone models, and the digital models. Time-dependent deformation of alginate impressions at different storage periods and the accuracy of traditional stone models and digital models were evaluated separately. Both the stone models and the digital models were highly correlated with the master model. Significant deformities in the alginate impressions were noted at different storage periods of 1 to 4 days. Alginate impressions of different brands also showed significant differences between each other on the first, third, and fourth days. Digital orthodontic models are as reliable as traditional stone models and probably will become the standard for orthodontic clinical use. Storing alginate impressions in sealed plastic bags for up to 4 days caused statistically significant deformation of alginate impressions, but the magnitude of these deformations did not appear to be clinically relevant and had no adverse effect on digital modeling.
NASA Astrophysics Data System (ADS)
Kerschke, Dorit; Schilling, Maik; Simon, Andreas; Wächter, Joachim
2014-05-01
The Energiewende and the increasing scarcity of raw materials will lead to an intensified utilization of the subsurface in Germany. Within this context, geological 3D modeling is a fundamental approach for integrated decision and planning processes. Initiated by the development of the European Geospatial Infrastructure INSPIRE, the German State Geological Offices started digitizing their predominantly analog archive inventory. Until now, a comprehensive 3D subsurface model of Brandenburg did not exist. Therefore the project B3D strived to develop a new 3D model as well as a subsequent infrastructure node to integrate all geological and spatial data within the Geodaten-Infrastruktur Brandenburg (Geospatial Infrastructure, GDI-BB) and provide it to the public through an interactive 2D/3D web application. The functionality of the web application is based on a client-server architecture. Server-sided, all available spatial data is published through GeoServer. GeoServer is designed for interoperability and acts as the reference implementation of the Open Geospatial Consortium (OGC) Web Feature Service (WFS) standard that provides the interface that allows requests for geographical features. In addition, GeoServer implements, among others, the high performance certified compliant Web Map Service (WMS) that serves geo-referenced map images. For publishing 3D data, the OGC Web 3D Service (W3DS), a portrayal service for three-dimensional geo-data, is used. The W3DS displays elements representing the geometry, appearance, and behavior of geographic objects. On the client side, the web application is solely based on Free and Open Source Software and leans on the JavaScript API WebGL that allows the interactive rendering of 2D and 3D graphics by means of GPU accelerated usage of physics and image processing as part of the web page canvas without the use of plug-ins. WebGL is supported by most web browsers (e.g., Google Chrome, Mozilla Firefox, Safari, and Opera). The web
Faceless identification: a model for person identification using the 3D shape and 3D motion as cues
NASA Astrophysics Data System (ADS)
Klasen, Lena M.; Li, Haibo
1999-02-01
Person identification by using biometric methods based on image sequences, or still images, often requires a controllable and cooperative environment during the image capturing stage. In the forensic case the situation is more likely to be the opposite. In this work we propose a method that makes use of the anthropometry of the human body and human actions as cues for identification. Image sequences from surveillance systems are used, which can be seen as monocular image sequences. A 3D deformable wireframe body model is used as a platform to handle the non-rigid information of the 3D shape and 3D motion of the human body from the image sequence. A recursive method for estimating global motion and local shape variations is presented, using two recursive feedback systems.
1D-3D hybrid modeling-from multi-compartment models to full resolution models in space and time.
Grein, Stephan; Stepniewski, Martin; Reiter, Sebastian; Knodel, Markus M; Queisser, Gillian
2014-01-01
Investigation of cellular and network dynamics in the brain by means of modeling and simulation has evolved into a highly interdisciplinary field, that uses sophisticated modeling and simulation approaches to understand distinct areas of brain function. Depending on the underlying complexity, these models vary in their level of detail, in order to cope with the attached computational cost. Hence for large network simulations, single neurons are typically reduced to time-dependent signal processors, dismissing the spatial aspect of each cell. For single cell or networks with relatively small numbers of neurons, general purpose simulators allow for space and time-dependent simulations of electrical signal processing, based on the cable equation theory. An emerging field in Computational Neuroscience encompasses a new level of detail by incorporating the full three-dimensional morphology of cells and organelles into three-dimensional, space and time-dependent, simulations. While every approach has its advantages and limitations, such as computational cost, integrated and methods-spanning simulation approaches, depending on the network size could establish new ways to investigate the brain. In this paper we present a hybrid simulation approach, that makes use of reduced 1D-models using e.g., the NEURON simulator-which couples to fully resolved models for simulating cellular and sub-cellular dynamics, including the detailed three-dimensional morphology of neurons and organelles. In order to couple 1D- and 3D-simulations, we present a geometry-, membrane potential- and intracellular concentration mapping framework, with which graph- based morphologies, e.g., in the swc- or hoc-format, are mapped to full surface and volume representations of the neuron and computational data from 1D-simulations can be used as boundary conditions for full 3D simulations and vice versa. Thus, established models and data, based on general purpose 1D-simulators, can be directly coupled to the
Quality assessment of watermarked 3D polygonal models
NASA Astrophysics Data System (ADS)
Funk, Wolfgang; Prasiswa, Jennifer
2006-02-01
In this paper, we present the design and results of subjective tests for evaluating the perceptibility of digital watermarks in 3D polygonal models. Based on the results we investigate different types of metrics with respect to their usefulness as predictors for the perceived visual quality of models that have been modified using a specific watermarking algorithm. We describe two experiments with models that have been watermarked using controlled free form deformations. The first experiment was conducted in supervised mode with still images of rendered models as stimuli and used the Two Alternative Forced Choice (2AFC) method. The second experiment was based on animated sequences and run in 2AFC mode with additional ratings of the perceived differences, but without assistance by the experimenter. We present a transparency analysis of the results and investigate the ability of image-based and geometry-based metrics to predict the perceived quality of the watermarked models. Our results show that the effectiveness of prediction depends on the type of model and in particular on the feature positions selected by the watermarking algorithm. The results of previous experiments with simplified polygonal models are confirmed, in that geometric measures are good predictors of quality ratings. We found that the symmetric Haussdorf distance is a promising candidate to evaluate the visual impact of the watermarking algorithm used in our experiments.
NASA Astrophysics Data System (ADS)
Maurer, J.; Segall, P.
2015-12-01
Understanding and predicting earthquake magnitudes from injection-induced seismicity is critically important for estimating hazard due to injection operations. A particular problem has been that the largest event often occurs post shut-in. A rigorous analysis would require modeling all stages of earthquake nucleation, propagation, and arrest, and not just initiation. We present a simple conceptual model for predicting the distribution of earthquake magnitudes during and following injection, building on the analysis of Segall & Lu (2015). The analysis requires several assumptions: (1) the distribution of source dimensions follows a Gutenberg-Richter distribution; (2) in environments where the background ratio of shear to effective normal stress is low, the size of induced events is limited by the volume perturbed by injection (e.g., Shapiro et al., 2013; McGarr, 2014), and (3) the perturbed volume can be approximated by diffusion in a homogeneous medium. Evidence for the second assumption comes from numerical studies that indicate the background ratio of shear to normal stress controls how far an earthquake rupture, once initiated, can grow (Dunham et al., 2011; Schmitt et al., submitted). We derive analytical expressions that give the rate of events of a given magnitude as the product of three terms: the time-dependent rate of nucleations, the probability of nucleating on a source of given size (from the Gutenberg-Richter distribution), and a time-dependent geometrical factor. We verify our results using simulations and demonstrate characteristics observed in real induced sequences, such as time-dependent b-values and the occurrence of the largest event post injection. We compare results to Segall & Lu (2015) as well as example datasets. Future work includes using 2D numerical simulations to test our results and assumptions; in particular, investigating how background shear stress and fault roughness control rupture extent.
3D model generation using an airborne swarm
NASA Astrophysics Data System (ADS)
Clark, R. A.; Punzo, G.; Dobie, G.; MacLeod, C. N.; Summan, R.; Pierce, G.; Macdonald, M.; Bolton, G.
2015-03-01
Using an artificial kinematic field to provide co-ordination between multiple inspection UAVs, the authors herein demonstrate full 3D modelling capability based on a photogrammetric system. The operation of the system is demonstrated by generating a full 3D surface model of an intermediate level nuclear waste storage drum. Such drums require periodic inspection to ensure that drum distortion or corrosion is carefully monitored. Performing this inspection with multiple airborne platforms enables rapid inspection of structures that are inaccessible to on-surface remote vehicles and are in human-hazardous environments. A three-dimensional surface-meshed model of the target can then be constructed in post-processing through photogrammetry analysis of the visual inspection data. The inspection environment uses a tracking system to precisely monitor the position of each aerial vehicle within the enclosure. The vehicles used are commercially available Parrot AR. Drone quadcopters, controlled through a computer interface connected over an IEEE 802.11n (WiFi) network, implementing a distributed controller for each vehicle. This enables the autonomous and distributed elements of the control scheme to be retained, while alleviating the vehicles of the control algorithm's computational load. The control scheme relies on a kinematic field defined with the target at its centre. This field defines the trajectory for all the drones in the volume relative to the central target, enabling the drones to circle the target at a set radius while avoiding drone collisions. This function enables complete coverage along the height of the object, which is assured by transitioning to another inspection band only after completing circumferential coverage. Using a swarm of vehicles, the time until complete coverage can be significantly reduced.
3-D numerical modeling of plume-induced subduction initiation
NASA Astrophysics Data System (ADS)
Baes, Marzieh; Gerya, taras; Sobolev, Stephan
2016-04-01
Investigation of mechanisms involved in formation of a new subduction zone can help us to better understand plate tectonics. Despite numerous previous studies, it is still unclear how and where an old oceanic plate starts to subduct beneath the other plate. One of the proposed scenarios for nucleation of subduction is plume-induced subduction initiation, which was investigated in detail, using 2-D models, by Ueda et al. (2008). Recently. Gerya et al. (2015), using 3D numerical models, proposed that plume-lithosphere interaction in the Archean led to the subduction initiation and onset of plate tectonic. In this study, we aim to pursue work of Ueda et al. (2008) by incorporation of 3-D thermo-mechanical models to investigate conditions leading to oceanic subduction initiation as a result of thermal-chemical mantle plume-lithosphere interaction in the modern earth. Results of our experiments show four different deformation regimes in response to plume-lithosphere interaction, that are a) self-sustaining subduction initiation where subduction becomes self-sustained, b) freezing subduction initiation where subduction stops at shallow depths, c) slab break-off where subducting circular slab breaks off soon after formation and d) plume underplating where plume does not pass through the lithosphere but spreads beneath it (failed subduction initiation). These different regimes depend on several parameters such as plume's size, composition and temperature, lithospheric brittle/plastic strength, age of the oceanic lithosphere and presence/absence of lithospheric heterogeneities. Results show that subduction initiates and becomes self-sustained when lithosphere is older than 10 Myr and non-dimensional ratio of the plume buoyancy force and lithospheric strength above the plume is higher than 2.
3D model generation using an airborne swarm
Clark, R. A.; Punzo, G.; Macdonald, M.; Dobie, G.; MacLeod, C. N.; Summan, R.; Pierce, G.; Bolton, G.
2015-03-31
Using an artificial kinematic field to provide co-ordination between multiple inspection UAVs, the authors herein demonstrate full 3D modelling capability based on a photogrammetric system. The operation of the system is demonstrated by generating a full 3D surface model of an intermediate level nuclear waste storage drum. Such drums require periodic inspection to ensure that drum distortion or corrosion is carefully monitored. Performing this inspection with multiple airborne platforms enables rapid inspection of structures that are inaccessible to on-surface remote vehicles and are in human-hazardous environments. A three-dimensional surface-meshed model of the target can then be constructed in post-processing through photogrammetry analysis of the visual inspection data. The inspection environment uses a tracking system to precisely monitor the position of each aerial vehicle within the enclosure. The vehicles used are commercially available Parrot AR. Drone quadcopters, controlled through a computer interface connected over an IEEE 802.11n (WiFi) network, implementing a distributed controller for each vehicle. This enables the autonomous and distributed elements of the control scheme to be retained, while alleviating the vehicles of the control algorithm’s computational load. The control scheme relies on a kinematic field defined with the target at its centre. This field defines the trajectory for all the drones in the volume relative to the central target, enabling the drones to circle the target at a set radius while avoiding drone collisions. This function enables complete coverage along the height of the object, which is assured by transitioning to another inspection band only after completing circumferential coverage. Using a swarm of vehicles, the time until complete coverage can be significantly reduced.
Handheld camera 3D modeling system using multiple reference panels
NASA Astrophysics Data System (ADS)
Fujimura, Kouta; Oue, Yasuhiro; Terauchi, Tomoya; Emi, Tetsuichi
2002-03-01
A novel 3D modeling system in which a target object is easily captured and modeled by using a hand-held camera with several reference panels is presented in this paper. The reference panels are designed to be able to obtain the camera position and discriminate between each other. A conventional 3D modeling system using a reference panel has several restrictions regarding the target object, specifically the size and its location. Our system uses multiple reference panels, which are set around the target object to remove these restrictions. The main features of this system are as follows: 1) The whole shape and photo-realistic textures of the target object can be digitized based on several still images or a movie captured by using a hand-held camera; as well as each location of the camera that can be calculated using the reference panels. 2) Our system can be provided as a software product only. That means there are no special requirements for hardware; even the reference panels , because they can be printed from image files or software. 3) This system can be applied to digitize a larger object. In the experiments, we developed and used an interactive region selection tool to detect the silhouette on each image instead of using the chroma -keying method. We have tested our system with a toy object. The calculation time is about 10 minutes (except for the capturing the images and extracting the silhouette by using our tool) on a personal computer with a Pentium-III processor (600MHz) and 320MB memory. However, it depends on how complex the images are and how many images you use. Our future plan is to evaluate the system with various kind of objects, specifically, large ones in outdoor environments.
NASA Astrophysics Data System (ADS)
Margerin, Ludovic; Calvet, Marie
2013-04-01
The attenuation properties of the crust have been widely explored from measurements of the quality factor of coda waves (Qc) throughout the world. A number of studies have reported an increase of Qc with the lapse time in the coda of shear waves excited by local earthquakes. Based on a single-scattering interpretation, this observation is generally ascribed to depth-dependent attenuation properties in the crust. In recent years a number of observations -in particular seismic wave equipartition- have put forward the importance of multiple scattering in the coda. The main purpose of this study is therefore to clarify the role of multiple scattering in the lapse time dependence of Qc using numerical simulations and observations from the Pyrenees. Thanks to the European project Interreg SISPYR, we collected all available waveform data from various institutions that operate seismological networks along the range. We selected around 5000 waveforms from 159 local earthquakes (with a magnitude larger than 3) which occured between 2001 and 2010. The coda quality factor of short-period S-waves has been measured as a function of the length of the coda window (Lw) for different choices of the onset time of the coda. In the 2-16 Hz frequency band, we observe a transient regime characterized by an increase of Qc with Lw, followed by a stabilization around a plateau whose value depends on the central frequency of the signal and on the location along the range. Using Monte Carlo simulations of wave transport in a variety of random media (exponential, Von-Karman or gaussian heterogeneity power spectra), we demonstrate that the lapse-time dependence of Qc in the Pyrenees may be modeled by anisotropic multiple scattering of seismic waves, without invoking any depth dependence of the attenuation properties in the crust. In our model, anisotropic scattering is quantified by the ratio between the transport and scattering mean path (l*-l). At 6 Hz, we show that pyrenean data require an
NASA Astrophysics Data System (ADS)
Calvet, M.; Margerin, L.
2012-12-01
The attenuation properties of the crust have been widely explored from measurements of the quality factor of coda waves (Qc) throughout the world. A number of studies have reported an increase of Qc with the lapse time in the coda of shear waves excited by local earthquakes. Based on a single scattering interpretation, this observation is generally ascribed to depth-dependent attenuation properties in the crust. In recent years a number of observations -in particular seismic wave equipartition- have put forward the importance of multiple scattering in the coda. The main purpose of this study is therefore to clarify the role of multiple scattering in the lapse time dependence of Qc using numerical simulations and observations from the Pyrenees. Thanks to the European project Interreg SISPYR, we collected all available waveform data from various institutions that operate seismological networks along the range. We selected around 5000 waveforms from 159 local earthquakes (with a magnitude larger than 3) which occured between 2001 and 2010. The coda quality factor of short-period S-waves has been measured as a function of the length of the coda window (Lw) for different choices of the onset time of the coda. In the 2-16 Hz frequency band, we observe a transient regime characterized by an increase of Qc with Lw, followed by a stabilization around a plateau whose value depends on the central frequency of the signal and on the location along the range. Using Monte Carlo simulations of wave transport in a variety of random media (exponential, Von-Karman or gaussian heterogeneity power spectra), we demonstrate that the lapse-time dependence of Qc in the Pyrenees may be modeled by anisotropic multiple scattering of seismic waves, without invoking any depth dependence of the attenuation properties in the crust. In our model, anisotropic scattering is quantified by the ratio between the transport and scattering mean path (l*/l). At 6 Hz, we show that pyrenean data require an
Time-dependent evolution of rock slopes by a multi-modelling approach
NASA Astrophysics Data System (ADS)
Bozzano, F.; Della Seta, M.; Martino, S.
2016-06-01
This paper presents a multi-modelling approach that incorporates contributions from morpho-evolutionary modelling, detailed engineering-geological modelling and time-dependent stress-strain numerical modelling to analyse the rheological evolution of a river valley slope over approximately 102 kyr. The slope is located in a transient, tectonically active landscape in southwestern Tyrrhenian Calabria (Italy), where gravitational processes drive failures in rock slopes. Constraints on the valley profile development were provided by a morpho-evolutionary model based on the correlation of marine and river strath terraces. Rock mass classes were identified through geomechanical parameters that were derived from engineering-geological surveys and outputs of a multi-sensor slope monitoring system. The rock mass classes were associated to lithotechnical units to obtain a high-resolution engineering-geological model along a cross section of the valley. Time-dependent stress-strain numerical modelling reproduced the main morpho-evolutionary stages of the valley slopes. The findings demonstrate that a complex combination of eustatism, uplift and Mass Rock Creep (MRC) deformations can lead to first-time failures of rock slopes when unstable conditions are encountered up to the generation of stress-controlled shear zones. The multi-modelling approach enabled us to determine that such complex combinations may have been sufficient for the first-time failure of the S. Giovanni slope at approximately 140 ka (MIS 7), even without invoking any trigger. Conversely, further reactivations of the landslide must be related to triggers such as earthquakes, rainfall and anthropogenic activities. This failure involved a portion of the slope where a plasticity zone resulted from mass rock creep that evolved with a maximum strain rate of 40% per thousand years, after the formation of a river strath terrace. This study demonstrates that the multi-modelling approach presented herein is a useful
Validating a time-dependent turbulence-driven model of the solar wind
Lionello, Roberto; Downs, Cooper; Linker, Jon A.; Mikić, Zoran; Velli, Marco; Verdini, Andrea E-mail: cdowns@predsci.com E-mail: mikic@predsci.com E-mail: verdini@oma.be
2014-04-01
Although the mechanisms responsible for heating the Sun's corona and accelerating the solar wind are still being actively investigated, it is largely accepted that photospheric motions provide the energy source and that the magnetic field must play a key role in the process. Verdini et al. presented a model for heating and accelerating the solar wind based on the turbulent dissipation of Alfvén waves. We first use a time-dependent model of the solar wind to reproduce one of Verdini et al.'s solutions; then, we extend its application to the case where the energy equation includes thermal conduction and radiation losses, and the upper chromosphere is part of the computational domain. Using this model, we explore the parameter space and describe the characteristics of a fast solar wind solution. We discuss how this formulation may be applied to a three-dimensional MHD model of the corona and solar wind.
Constitutive modeling of time-dependent response of human plantar aponeurosis.
Pavan, P G; Pachera, P; Stecco, C; Natali, A N
2014-01-01
The attention is focused on the viscoelastic behavior of human plantar aponeurosis tissue. At this purpose, stress relaxation tests were developed on samples taken from the plantar aponeurosis of frozen adult donors with age ranging from 67 to 78 years, imposing three levels of strain in the physiological range (4%, 6%, and 8%) and observing stress decay for 240 s. A viscohyperelastic fiber-reinforced constitutive model with transverse isotropy was assumed to describe the time-dependent behavior of the aponeurotic tissue. This model is consistent with the structural conformation of the tissue where collagen fibers are mainly aligned with the proximal-distal direction. Constitutive model fitting to experimental data was made by implementing a stochastic-deterministic procedure. The stress relaxation was found close to 40%, independently of the level of strain applied. The agreement between experimental data and numerical results confirms the suitability of the constitutive model to describe the viscoelastic behaviour of the plantar aponeurosis.
Graupner, Michael; Brunel, Nicolas
2010-01-01
We review biophysical models of synaptic plasticity, with a focus on spike-timing dependent plasticity (STDP). The common property of the discussed models is that synaptic changes depend on the dynamics of the intracellular calcium concentration, which itself depends on pre- and postsynaptic activity. We start by discussing simple models in which plasticity changes are based directly on calcium amplitude and dynamics. We then consider models in which dynamic intracellular signaling cascades form the link between the calcium dynamics and the plasticity changes. Both mechanisms of induction of STDP (through the ability of pre/postsynaptic spikes to evoke changes in the state of the synapse) and of maintenance of the evoked changes (through bistability) are discussed. PMID:20948584
Non-Hermitian Swanson model with a time-dependent metric
NASA Astrophysics Data System (ADS)
Fring, Andreas; Moussa, Miled H. Y.
2016-10-01
We provide further nontrivial solutions to the recently proposed time-dependent Dyson and quasi-Hermiticity relation. Here, we solve them for the generalized version of the non-Hermitian Swanson Hamiltonian with time-dependent coefficients. We construct time-dependent solutions by employing the Lewis-Riesenfeld method of invariants and discuss concrete physical applications of our results.
Crashworthiness analysis using advanced material models in DYNA3D
Logan, R.W.; Burger, M.J.; McMichael, L.D.; Parkinson, R.D.
1993-10-22
As part of an electric vehicle consortium, LLNL and Kaiser Aluminum are conducting experimental and numerical studies on crashworthy aluminum spaceframe designs. They have jointly explored the effect of heat treat on crush behavior and duplicated the experimental behavior with finite-element simulations. The major technical contributions to the state of the art in numerical simulation arise from the development and use of advanced material model descriptions for LLNL`s DYNA3D code. Constitutive model enhancements in both flow and failure have been employed for conventional materials such as low-carbon steels, and also for lighter weight materials such as aluminum and fiber composites being considered for future vehicles. The constitutive model enhancements are developed as extensions from LLNL`s work in anisotropic flow and multiaxial failure modeling. Analysis quality as a function of level of simplification of material behavior and mesh is explored, as well as the penalty in computation cost that must be paid for using more complex models and meshes. The lightweight material modeling technology is being used at the vehicle component level to explore the safety implications of small neighborhood electric vehicles manufactured almost exclusively from these materials.
A 3-D model of coronary vessel development.
Nesbitt, Tresa L; Patel, Payal A; Yost, Michael J; Goodwin, Richard L; Potts, Jay D
2007-01-01
Coronary vascular disease is one of the leading causes of mortality and morbidity in the United States. Therefore, a mechanistic understanding of coronary vessel morphogenesis would aid in the innovation of new therapies targeting vascular disorders. Moreover, a functionally equivalent in vitro model system allows for the delineation of the molecular mechanisms that regulate coronary vessel development. In this study, we present a novel in vitro model system. This three-dimensional (3-D) model system consists of a tubular scaffold, which is engineered from type-I collagen and has been optimized to support the growth of embryonic cardiac tissues. In this report, proepicardial (PE) cells, the developmental precursors of coronary vessels, have been isolated from several model species and cultured on this scaffold. In this model system, the PE cells were able to recapitulate several aspects of coronary vessel morphogenesis including epicardial formation, the epicardial to mesenchymal transformation, and de novo coronary vessel development or vasculogenesis. The differentiation of PE cells was characterized using a variety of specific protein markers. The potential uses of this novel coronary developmental model are discussed.
Energy flow in passive and active 3D cochlear model
Wang, Yanli; Steele, Charles; Puria, Sunil
2015-12-31
Energy flow in the cochlea is an important characteristic of the cochlear traveling wave, and many investigators, such as von Békésy and Lighthill, have discussed this phenomenon. Particularly after the discovery of the motility of the outer hair cells (OHCs), the nature of the power gain of the cochlea has been a fundamental research question. In the present work, direct three-dimensional (3D) calculations of the power on cross sections of the cochlea and on the basilar membrane are performed based on a box model of the mouse cochlea. The distributions of the fluid pressure and fluid velocity in the scala vestibuli are presented. The power output from the OHCs and the power loss due to fluid viscous damping are calculated along the length of the cochlea. This work provides a basis for theoretical calculations of the power gain of the OHCs from mechanical considerations.
3D Model of the San Emidio Geothermal Area
James E. Faulds
2013-12-31
The San Emidio geothermal system is characterized by a left-step in a west-dipping normal fault system that bounds the western side of the Lake Range. The 3D geologic model consists of 5 geologic units and 55 faults. Overlying Jurrassic-Triassic metasedimentary basement is a ~500 m-1000 m thick section of the Miocene lower Pyramid sequence, pre- syn-extensional Quaternary sedimentary rocks and post-extensional Quaternary rocks. 15-30º eastward dip of the stratigraphy is controlled by the predominant west-dipping fault set. Both geothermal production and injection are concentrated north of the step over in an area of closely spaced west dipping normal faults.
3D Model of the Neal Hot Springs Geothermal Area
Faulds, James E.
2013-12-31
The Neal Hot Springs geothermal system lies in a left-step in a north-striking, west-dipping normal fault system, consisting of the Neal Fault to the south and the Sugarloaf Butte Fault to the north (Edwards, 2013). The Neal Hot Springs 3D geologic model consists of 104 faults and 13 stratigraphic units. The stratigraphy is sub-horizontal to dipping <10 degrees and there is no predominant dip-direction. Geothermal production is exclusively from the Neal Fault south of, and within the step-over, while geothermal injection is into both the Neal Fault to the south of the step-over and faults within the step-over.
Appearance-based color face recognition with 3D model
NASA Astrophysics Data System (ADS)
Wang, Chengzhang; Bai, Xiaoming
2013-03-01
Appearance-based face recognition approaches explore color cues of face images, i.e. grey or color information for recognition task. They first encode color face images, and then extract facial features for classification. Similar to conventional singular value decomposition, hypercomplex matrix also exists singular value decomposition on hypercomplex field. In this paper, a novel color face recognition approach based on hypercomplex singular value decomposition is proposed. The approach employs hypercomplex to encode color face information of different channels simultaneously. Hypercomplex singular value decomposition is utilized then to compute the basis vectors of the color face subspace. To improve learning efficiency of the algorithm, 3D active deformable model is exploited to generate virtual face images. Color face samples are projected onto the subspace and projection coefficients are utilized as facial features. Experimental results on CMU PIE face database verify the effectiveness of the proposed approach.
3D model atmospheres and the solar photospheric oxygen abundance
NASA Astrophysics Data System (ADS)
Caffau, E.; Ludwig, H.-G.
2008-10-01
In recent years the photospheric solar oxygen abundance experienced a significant downward revision. However, a low photospheric abundance is incompatible with the value in the solar interior inferred from helioseismology. For contributing to the dispute whether the solar oxygen abundance is “high” or “low”, we re-derived its photospheric abundance independently of previous analyses. We applied 3D (CO5BOLD) as well as 1D model atmospheres. We considered standard disc-centre and disc-integrated spectral atlases, as well as newly acquired solar intensity spectra at different heliocentric angles. We determined the oxygen abundances from equivalent width and/or line profile fitting of a number of atomic lines. As preliminary result, we find an oxygen abundance in the range 8.73 8.79, encompassing the value obtained by Holweger (2001), and somewhat higher than the value obtained by Asplund et al. (2005).
Energy flow in passive and active 3D cochlear model
NASA Astrophysics Data System (ADS)
Wang, Yanli; Puria, Sunil; Steele, Charles
2015-12-01
Energy flow in the cochlea is an important characteristic of the cochlear traveling wave, and many investigators, such as von Békésy and Lighthill, have discussed this phenomenon. Particularly after the discovery of the motility of the outer hair cells (OHCs), the nature of the power gain of the cochlea has been a fundamental research question. In the present work, direct three-dimensional (3D) calculations of the power on cross sections of the cochlea and on the basilar membrane are performed based on a box model of the mouse cochlea. The distributions of the fluid pressure and fluid velocity in the scala vestibuli are presented. The power output from the OHCs and the power loss due to fluid viscous damping are calculated along the length of the cochlea. This work provides a basis for theoretical calculations of the power gain of the OHCs from mechanical considerations.
Towards Automatic Semantic Labelling of 3D City Models
NASA Astrophysics Data System (ADS)
Rook, M.; Biljecki, F.; Diakité, A. A.
2016-10-01
The lack of semantic information in many 3D city models is a considerable limiting factor in their use, as a lot of applications rely on semantics. Such information is not always available, since it is not collected at all times, it might be lost due to data transformation, or its lack may be caused by non-interoperability in data integration from other sources. This research is a first step in creating an automatic workflow that semantically labels plain 3D city model represented by a soup of polygons, with semantic and thematic information, as defined in the CityGML standard. The first step involves the reconstruction of the topology, which is used in a region growing algorithm that clusters upward facing adjacent triangles. Heuristic rules, embedded in a decision tree, are used to compute a likeliness score for these regions that either represent the ground (terrain) or a RoofSurface. Regions with a high likeliness score, to one of the two classes, are used to create a decision space, which is used in a support vector machine (SVM). Next, topological relations are utilised to select seeds that function as a start in a region growing algorithm, to create regions of triangles of other semantic classes. The topological relationships of the regions are used in the aggregation of the thematic building features. Finally, the level of detail is detected to generate the correct output in CityGML. The results show an accuracy between 85 % and 99 % in the automatic semantic labelling on four different test datasets. The paper is concluded by indicating problems and difficulties implying the next steps in the research.
An advanced time-dependent collisional-radiative model of helium plasma discharges
NASA Astrophysics Data System (ADS)
Claustre, J.; Boukandou-Mombo, C.; Margot, J.; Matte, J.-P.; Vidal, F.
2017-10-01
A new spatially averaged time-dependent collisional-radiative model for helium plasmas, coupled to the electron Boltzmann equation (EBE), has been developed. Its main novelties are: (1) full time dependence for both the multi-species kinetics and the EBE. It is shown that this is necessary to correctly simulate discharges where the parameters vary on nanoseconds-microsecond timescales. (2) All electron processes are accounted for accurately. In particular, for the various ionization and recombination processes, free electrons are added or removed at the appropriate energy, with the appropriate interpolation on the energy grid. (3) The energy dependence of the electron loss by ambipolar diffusion is taken into account approximately. (4) All of the processes which are known to be important in helium discharges for pressure P≤slant 760 Torr are included, and 42 energy levels up to n = 6, where n is the main quantum number, are taken into account. Atomic and molecular ions, as well as excimers, are also included. (5) The gas temperature is calculated self-consistently. The model is validated through comparisons with known numerical steady-state results of Santos et al (2014 J. Phys. D. 47 265201) which they compared to their experimental results, and good agreement is obtained for their measured quantities. It is then applied to post-discharge decay cases with very short power decay times. The time evolution of the population densities and reaction rates are analyzed in detail with emphasis on the observed large increase of the metastable density.
A simplified time-dependent recovery model as applied to RCP seal LOCAs
Kohut, P.; Bozoki, G.; Fitzpatrick, R. )
1991-01-01
In Westinghouse-designed reactors, the reactor coolant pump (RCP) seals constantly require a modest amount of cooling. This cooling function depends on the service water (SW) system. Upon the loss of the cooling function due to the unavailability of the SW, component cooling water system or electrical power (station blackout), the RCP seals may degrade, resulting in a loss-of-coolant accident (LOCA). Recent studies indicate that the frequency of the loss of SW initiating events is higher than previously thought. This change significantly increases the core damage frequency contribution from RCP seal failure. The most critical/dominant element in the loss of SW events was found to be the SW-induced RCP seal failure. For these potential accident scenarios, there are large uncertainties regarding the actual frequency of RCP seal LOCA, the resulting leakage rate, and time-dependent behavior. The roles of various recovery options based on the time evolution of the seal LOCA have been identified and taken into account in recent NUREG-1150 probabilistic risk assessment PRA analyses. In this paper, a consistent time-dependent recovery model is described that takes into account the effects of various recovery actions based on explicit considerations given to a spectrum of time- and flow-rate dependencies. The model represents a simplified approach but is especially useful when extensive seal leak rate and core uncovery information is unavailable.
NASA Astrophysics Data System (ADS)
Reyes, Jonathan; Shadwick, B. A.
2016-10-01
Modeling the evolution of a short, intense laser pulse propagating through an underdense plasma is of particular interest in the physics of laser-plasma interactions. Numerical models are typically created by first discretizing the equations of motion and then imposing boundary conditions. Using the variational principle of Chen and Sudan, we spatially discretize the Lagrangian density to obtain discrete equations of motion and a discrete energy conservation law which is exactly satisfied regardless of the spatial grid resolution. Modifying the derived equations of motion (e.g., enforcing boundary conditions) generally ruins energy conservation. However, time-dependent terms can be added to the Lagrangian which force the equations of motion to have the desired boundary conditions. Although some foresight is needed to choose these time-dependent terms, this approach provides a mechanism for energy to exit the closed system while allowing the conservation law to account for the loss. An appropriate time discretization scheme is selected based on stability analysis and resolution requirements. We present results using this variational approach in a co-moving coordinate system and compare such results to those using traditional second-order methods. This work was supported by the U. S. Department of Energy under Contract No. DE-SC0008382 and by the National Science Foundation under Contract No. PHY- 1104683.
A GIS-based time-dependent seismic source modeling of Northern Iran
NASA Astrophysics Data System (ADS)
Hashemi, Mahdi; Alesheikh, Ali Asghar; Zolfaghari, Mohammad Reza
2017-01-01
The first step in any seismic hazard study is the definition of seismogenic sources and the estimation of magnitude-frequency relationships for each source. There is as yet no standard methodology for source modeling and many researchers have worked on this topic. This study is an effort to define linear and area seismic sources for Northern Iran. The linear or fault sources are developed based on tectonic features and characteristic earthquakes while the area sources are developed based on spatial distribution of small to moderate earthquakes. Time-dependent recurrence relationships are developed for fault sources using renewal approach while time-independent frequency-magnitude relationships are proposed for area sources based on Poisson process. GIS functionalities are used in this study to introduce and incorporate spatial-temporal and geostatistical indices in delineating area seismic sources. The proposed methodology is used to model seismic sources for an area of about 500 by 400 square kilometers around Tehran. Previous researches and reports are studied to compile an earthquake/fault catalog that is as complete as possible. All events are transformed to uniform magnitude scale; duplicate events and dependent shocks are removed. Completeness and time distribution of the compiled catalog is taken into account. The proposed area and linear seismic sources in conjunction with defined recurrence relationships can be used to develop time-dependent probabilistic seismic hazard analysis of Northern Iran.
3D Model of the Tuscarora Geothermal Area
Faulds, James E.
2013-12-31
The Tuscarora geothermal system sits within a ~15 km wide left-step in a major west-dipping range-bounding normal fault system. The step over is defined by the Independence Mountains fault zone and the Bull Runs Mountains fault zone which overlap along strike. Strain is transferred between these major fault segments via and array of northerly striking normal faults with offsets of 10s to 100s of meters and strike lengths of less than 5 km. These faults within the step over are one to two orders of magnitude smaller than the range-bounding fault zones between which they reside. Faults within the broad step define an anticlinal accommodation zone wherein east-dipping faults mainly occupy western half of the accommodation zone and west-dipping faults lie in the eastern half of the accommodation zone. The 3D model of Tuscarora encompasses 70 small-offset normal faults that define the accommodation zone and a portion of the Independence Mountains fault zone, which dips beneath the geothermal field. The geothermal system resides in the axial part of the accommodation, straddling the two fault dip domains. The Tuscarora 3D geologic model consists of 10 stratigraphic units. Unconsolidated Quaternary alluvium has eroded down into bedrock units, the youngest and stratigraphically highest bedrock units are middle Miocene rhyolite and dacite flows regionally correlated with the Jarbidge Rhyolite and modeled with uniform cumulative thickness of ~350 m. Underlying these lava flows are Eocene volcanic rocks of the Big Cottonwood Canyon caldera. These units are modeled as intracaldera deposits, including domes, flows, and thick ash deposits that change in thickness and locally pinch out. The Paleozoic basement of consists metasedimenary and metavolcanic rocks, dominated by argillite, siltstone, limestone, quartzite, and metabasalt of the Schoonover and Snow Canyon Formations. Paleozoic formations are lumped in a single basement unit in the model. Fault blocks in the eastern
NASA Astrophysics Data System (ADS)
Jung, H.; Navarre-Sitchler, A.
2016-12-01
Several orders of magnitude difference between laboratory measured and field estimated weathering rates is a well-known knowledge gap that hampers extrapolating laboratory-measured weathering rates to natural systems. The influence of hydrologic heterogeneity has been recognized as an important factor affecting this discrepancy, but it has not been quantitatively linked to the time dependence of weathering rates. We evaluate the impact of heterogeneous fluid flow on the time dependence of anorthite weathering rate with fully coupled reactive transport simulator, Crunchflow. Simulations performed in correlated random permeability fields with log-normal distribution are compared to homogeneous permeability fields. Preliminary results reveal that flux-weighted weathering rates measured at the outlet of the domain are constant and independent to the degree of heterogeneity when the weathering front reside inside of the domain. However, the weathering rate starts to decrease with different reduction rate depending on the degree of heterogeneity after the front leaves the domain. The higher the degree of heterogeneity (i.e. the higher variance of the permeability distribution) the earlier the weathering front exits the domain and thus the earlier the reduction in weathering rate is observed, but the rate of reduction in weathering rate of this case is lower than the case with a low degree of heterogeneity. This is because of the development of a larger area of initially non-reactive zones that participate in the dissolution reaction at later time for the higher degree of heterogeneity case. The differences in the rate and timing of reduction lead to the reversal of the weathering rate over time. We are expecting this type of conceptual modeling approach to help elucidate hydrologic controls on the time dependence of effective reaction rates at field scales and improve the application of laboratory measured rates to numerical simulations of field scale systems.
A new 3D dynamical biomechanical tongue model
NASA Astrophysics Data System (ADS)
Gerard, Jean-Michel; Perrier, Pascal; Payan, Yohan; Wilhelms-Tricarico, Reiner
2004-05-01
A new dynamical biomechanical tongue model is being developed to study speech motor control. In spite of its computational complexity, a 3D representation was chosen in order to account for various contacts between tongue and external structures such as teeth, palate, and vocal tract walls. A fair representation of tongue muscle anatomy is provided, by designing the finite element mesh from the visible human data set (female subject). Model geometry was then matched to a human speaker, so that simulations can be quantitatively compared to experimental MRI data. A set of 11 muscles is modeled, whose role in speech gestures is well established. Each muscle is defined by a set of elements whose elastic properties change with muscle activation. Muscles forces are applied to the tongue model via macrofibers defined within the mesh by muscle specific sets of nodes. These forces are currently specified as step functions. Boundary conditions are set using zero-displacement nodes simulating attachments of tongue on bony structures. The nonlinear mechanical properties of tongue soft tissues are modeled using a hyperelastic material. Three-dimensional tongue deformations generated by each muscle, using FEM software ANSYS for computation, will be presented. Implications for speech motor control will be proposed.
A new 3D dynamical biomechanical tongue model
NASA Astrophysics Data System (ADS)
Gerard, Jean-Michel; Perrier, Pascal; Payan, Yohan; Wilhelms-Tricarico, Reiner
2001-05-01
A new dynamical biomechanical tongue model is being developed to study speech motor control. In spite of its computational complexity, a 3D representation was chosen in order to account for various contacts between tongue and external structures such as teeth, palate, and vocal tract walls. A fair representation of tongue muscle anatomy is provided, by designing the finite element mesh from the visible human data set (female subject). Model geometry was then matched to a human speaker, so that simulations can be quantitatively compared to experimental MRI data. A set of 11 muscles is modeled, whose role in speech gestures is well established. Each muscle is defined by a set of elements whose elastic properties change with muscle activation. Muscles forces are applied to the tongue model via macrofibers defined within the mesh by muscle specific sets of nodes. These forces are currently specified as step functions. Boundary conditions are set using zero-displacement nodes simulating attachments of tongue on bony structures. The nonlinear mechanical properties of tongue soft tissues are modeled using a hyperelastic material. Three-dimensional tongue deformations generated by each muscle, using FEM software ANSYS for computation, will be presented. Implications for speech motor control will be proposed.
A 3D parallel model of Ganymede's exosphere
NASA Astrophysics Data System (ADS)
Leclercq, Ludivine; Turc, Lucile; François, Leblanc; Ronan, Modolo
2013-04-01
Ganymede is a unique object : it is the biggest moon of our solar system, and the only satellite which has its own intrinsic magnetic field. Its surface is covered by water ice and by regolith. Some previous observations suggest that below its surface may exist an ocean of liquid water. The atmosphere of the planet is poorly known but should be composed essentially of water, hydrogen and oxygen (Marconi et al., Icarus, 2007). These atmospheric particles mainly originate from