Testing and tuning symplectic integrators for the hybrid Monte Carlo algorithm in lattice QCD
Takaishi, Tetsuya [Hiroshima University of Economics, Hiroshima 731-0124 (Japan); Forcrand, Philippe de [Physics Department, CERN, TH Unit, CH-1211 Geneva 23 (Switzerland); Institute for Theoretical Physics, ETH Zuerich, CH-8093 Zurich (Switzerland)
2006-03-15
We examine a new second-order integrator recently found by Omelyan et al. The integration error of the new integrator measured in the root mean square of the energy difference, <{delta}H{sup 2}>{sup 1/2}, is about 10 times smaller than that of the standard second-order leapfrog (2LF) integrator. As a result, the step size of the new integrator can be made about three times larger. Taking into account a factor 2 increase in cost, the new integrator is about 50% more efficient than the 2LF integrator. Integrating over positions first, then momenta, is slightly more advantageous than the reverse. Further parameter tuning is possible. We find that the optimal parameter for the new integrator is slightly different from the value obtained by Omelyan et al., and depends on the simulation parameters. This integrator could also be advantageous for the Trotter-Suzuki decomposition in quantum Monte Carlo.
Extra Chance Generalized Hybrid Monte Carlo
NASA Astrophysics Data System (ADS)
Campos, Cédric M.; Sanz-Serna, J. M.
2015-01-01
We study a method, Extra Chance Generalized Hybrid Monte Carlo, to avoid rejections in the Hybrid Monte Carlo method and related algorithms. In the spirit of delayed rejection, whenever a rejection would occur, extra work is done to find a fresh proposal that, hopefully, may be accepted. We present experiments that clearly indicate that the additional work per sample carried out in the extra chance approach clearly pays in terms of the quality of the samples generated.
NASA Astrophysics Data System (ADS)
Suzuki, Kimichi; Tachikawa, Masanori; Shiga, Motoyuki
2010-04-01
We propose an efficient path integral hybrid Monte Carlo (PIHMC) method based on fourth-order Trotter expansion. Here, the second-order effective force is employed to generate short trial trajectories to avoid computationally expensive Hessian matrix, while the final acceptance is judged based on fourth-order effective potential. The computational performance of our PIHMC scheme is compared with that of conventional PIHMC and PIMD methods based on second- and fourth-order Trotter expansions. Our method is applied to on-the-fly ab initio PIHMC calculation of fluoride ion-water complexes, F-(H2O) and F-(D2O), at ambient temperature, particularly focusing on the geometrical isotope effect.
Hybrid Silicon Integration R. Jones et al. Hybrid Silicon Integration
Bowers, John
Hybrid Silicon Integration R. Jones et al. 1 / 23 Hybrid Silicon Integration R. Jones1 , H. D. Park.jones@intel.com #12;Hybrid Silicon Integration R. Jones et al. 2 / 23 Hybrid Silicon Integration R. Jones1 , H. D.jones@intel.com Abstract: An overview is presented of the hybrid AlGaInAs-silicon platform that enables wafer level
Monte Carlo integration with subtraction
NASA Astrophysics Data System (ADS)
Arthur, Rudy; Kennedy, A. D.
2013-12-01
This paper investigates a class of algorithms for numerical integration of a function in d dimensions over a compact domain by Monte Carlo methods. We construct a histogram approximation to the function using a partition of the integration domain into a set of bins specified by some parameters. We then consider two adaptations: the first is to subtract the histogram approximation, whose integral we may easily evaluate explicitly, from the function and integrate the difference using Monte Carlo; the second is to modify the bin parameters in order to make the variance of the Monte Carlo estimate of the integral the same for all bins. This allows us to use Student’s t-test as a trigger for rebinning, which we claim is more stable than the ?2 test that is commonly used for this purpose. We provide a program that we have used to study the algorithm for the case where the histogram is represented as a product of one-dimensional histograms. We discuss the assumptions and approximations made, as well as giving a pedagogical discussion of the myriad ways in which the results of any such Monte Carlo integration program can be misleading.
The Rational Hybrid Monte Carlo Algorithm
M. A. Clark
2006-10-06
The past few years have seen considerable progress in algorithmic development for the generation of gauge fields including the effects of dynamical fermions. The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is performed using a rational approximation in place the usual inverse quark matrix kernel is one of these developments. This algorithm has been found to be extremely beneficial in many areas of lattice QCD (chiral fermions, finite temperature, Wilson fermions etc.). We review the algorithm and some of these benefits, and we compare against other recent algorithm developements. We conclude with an update of the Berlin wall plot comparing costs of all popular fermion formulations.
Multiple-time-stepping generalized hybrid Monte Carlo methods
NASA Astrophysics Data System (ADS)
Escribano, Bruno; Akhmatskaya, Elena; Reich, Sebastian; Azpiroz, Jon M.
2015-01-01
Performance of the generalized shadow hybrid Monte Carlo (GSHMC) method [1], which proved to be superior in sampling efficiency over its predecessors [2-4], molecular dynamics and hybrid Monte Carlo, can be further improved by combining it with multi-time-stepping (MTS) and mollification of slow forces. We demonstrate that the comparatively simple modifications of the method not only lead to better performance of GSHMC itself but also allow for beating the best performed methods, which use the similar force splitting schemes. In addition we show that the same ideas can be successfully applied to the conventional generalized hybrid Monte Carlo method (GHMC). The resulting methods, MTS-GHMC and MTS-GSHMC, provide accurate reproduction of thermodynamic and dynamical properties, exact temperature control during simulation and computational robustness and efficiency. MTS-GHMC uses a generalized momentum update to achieve weak stochastic stabilization to the molecular dynamics (MD) integrator. MTS-GSHMC adds the use of a shadow (modified) Hamiltonian to filter the MD trajectories in the HMC scheme. We introduce a new shadow Hamiltonian formulation adapted to force-splitting methods. The use of such Hamiltonians improves the acceptance rate of trajectories and has a strong impact on the sampling efficiency of the method. Both methods were implemented in the open-source MD package ProtoMol and were tested on a water and a protein systems. Results were compared to those obtained using a Langevin Molly (LM) method [5] on the same systems. The test results demonstrate the superiority of the new methods over LM in terms of stability, accuracy and sampling efficiency. This suggests that putting the MTS approach in the framework of hybrid Monte Carlo and using the natural stochasticity offered by the generalized hybrid Monte Carlo lead to improving stability of MTS and allow for achieving larger step sizes in the simulation of complex systems.
Monte Carlo Integration Lecture 2 The Problem
Liang, Faming
Monte Carlo Integration Lecture 2 The Problem Let be a probability measure over the Borel -field X S and h(x) = 0 otherwise. #12;Monte Carlo Integration Lecture 2 When the problem appears to be intractable, Press et al (1992) and reference therein). For high dimensional problems, Monte Carlo methods have
Advanced topics 5.1 Hybrid Monte Carlo
Schofield, Jeremy
5 Advanced topics 5.1 Hybrid Monte Carlo 5.1.1 The Method One drawback of traditional Monte-Carlo in a Monte-Carlo procedure. See S. Duane, A.D. Kennedy, B.J. Pendleton and D. Roweth, Phys. Lett. B 45, 216;5.1. HYBRID MONTE CARLO 89 · Claim: The transition probability Eq. (5.3) satisfies the stationarity condition
Hybrid algorithms in quantum Monte Carlo
NASA Astrophysics Data System (ADS)
Kim, Jeongnim; Esler, Kenneth P.; McMinis, Jeremy; Morales, Miguel A.; Clark, Bryan K.; Shulenburger, Luke; Ceperley, David M.
2012-12-01
With advances in algorithms and growing computing powers, quantum Monte Carlo (QMC) methods have become a leading contender for high accuracy calculations for the electronic structure of realistic systems. The performance gain on recent HPC systems is largely driven by increasing parallelism: the number of compute cores of a SMP and the number of SMPs have been going up, as the Top500 list attests. However, the available memory as well as the communication and memory bandwidth per element has not kept pace with the increasing parallelism. This severely limits the applicability of QMC and the problem size it can handle. OpenMP/MPI hybrid programming provides applications with simple but effective solutions to overcome efficiency and scalability bottlenecks on large-scale clusters based on multi/many-core SMPs. We discuss the design and implementation of hybrid methods in QMCPACK and analyze its performance on current HPC platforms characterized by various memory and communication hierarchies.
Configuration Path Integral Monte Carlo
NASA Astrophysics Data System (ADS)
Bonitz, Michael; Schoof, Tim; Groth, Simon; Filinov, Alexei; Hochstuhl, David
2011-11-01
A novel path integral Monte Carlo (PIMC) approach for correlated many-particle systems with arbitrary pair interaction in continuous space at low temperatures is presented. It is based on a representation of the N-particle density operator in a basis of (anti-)symmetrized N-particle states (``configurations'' of occupation numbers) [1]. The path integral is transformed into a sum over trajectories with the same topology and, finally, the limit of M to infinity, (M is the number of high-temperature factors), is analytically performed. This yields exact expressions for the thermodynamic quantities and allows to perform efficient simulations for fermions at low temperature and weak to moderate coupling. Our method is applicable to dense quantum plasmas in the regime of strong degeneracy where conventional PIMC, e.g. [2], fails due to the fermion sign problem. [4pt] [1] T. Schoof, M. Bonitz, A. Filinov, D. Hochstuhl, and J.W. Dufty, Contrib. Plasma Phys. (2011), DOI 10.1002/ctpp.201100012;.[0pt] [2] ``Introduction to computational methods for many-body physics,'' M. Bonitz and D. Semkat (eds.). Rinton Press, Princeton 2006, chapter 4.
Hybrid optofluidic integration.
Parks, Joshua W; Cai, Hong; Zempoaltecatl, Lynnell; Yuzvinsky, Thomas D; Leake, Kaelyn; Hawkins, Aaron R; Schmidt, Holger
2013-10-21
Complete integration of microfluidic and optical functions in a single lab-on-chip device is one goal of optofluidics. Here, we demonstrate the hybrid integration of a PDMS-based fluid handling layer with a silicon-based optical detection layer in a single optofluidic system. The optical layer consists of a liquid-core antiresonant reflecting optical waveguide (ARROW) chip that is capable of single particle detection and interfacing with optical fiber. Integrated devices are reconfigurable and able to sustain high pressures despite the small dimensions of the liquid-core waveguide channels. We show the combination of salient sample preparation capabilities-particle mixing, distribution, and filtering-with single particle fluorescence detection. Specifically, we demonstrate fluorescent labelling of ?-DNA, followed by flow-based single-molecule detection on a single device. This points the way towards amplification-free detection of nucleic acids with low-complexity biological sample preparation on a chip. PMID:23969694
Hybrid integrated circuits: A survey
P. Ingersoll
1977-01-01
Two proximity fuzes under development at the Harry Diamond Laboratories use thick-film hybrid integrated circuits. A survey of the hybrid integrated circuit industry was conducted to determine its capability to produce these circuits in volume within the continental United States. The circuits as complex as those used in XM587 and XM734 fuzes are in volume production using certain types of
Physically Based Rendering Monte Carlo Integration
Kazhdan, Michael
Computational Cost: 1. Russian Roulette 2. Splitting Reduce Variance: 1. Stratified sampling 2. Importance sampling #12;Russian Roulette Given a PDF p and a function f, the Monte- Carlo estimate of the integral is Roulette If f is expensive to evaluate and we know its value has to be small, we may want avoid calculating
Stanford University
Chapter 2 Monte Carlo Integration This chapter gives an introduction to Monte Carlo integration useful in computer graphics. Good references on Monte Carlo methods include Kalos & Whitlock [1986 for Monte Carlo applications to neutron transport problems; Lewis & Miller [1984] is a good source
Bayesian Training of Backpropagation Networks by the Hybrid Monte Carlo Method
Neal, Radford M.
Bayesian Training of Backpropagation Networks by the Hybrid Monte Carlo Method Radford M. Neal of backpropagation neural networks can feasibly be performed by the ``Hybrid Monte Carlo'' method. This approach by a Gaussian. In this work, the Hybrid Monte Carlo method is implemented in conjunction with simulated
Densmore, Jeffery D., E-mail: jdd@lanl.gov [Computational Physics and Methods Group, Los Alamos National Laboratory, P.O. Box 1663, MS D409, Los Alamos, NM 87545 (United States); Thompson, Kelly G., E-mail: kgt@lanl.gov [Computational Physics and Methods Group, Los Alamos National Laboratory, P.O. Box 1663, MS D409, Los Alamos, NM 87545 (United States); Urbatsch, Todd J., E-mail: tmonster@lanl.gov [Computational Physics and Methods Group, Los Alamos National Laboratory, P.O. Box 1663, MS D409, Los Alamos, NM 87545 (United States)
2012-08-15
Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Implicit Monte Carlo radiative-transfer simulations in optically thick media. In DDMC, particles take discrete steps between spatial cells according to a discretized diffusion equation. Each discrete step replaces many smaller Monte Carlo steps, thus improving the efficiency of the simulation. In this paper, we present an extension of DDMC for frequency-dependent radiative transfer. We base our new DDMC method on a frequency-integrated diffusion equation for frequencies below a specified threshold, as optical thickness is typically a decreasing function of frequency. Above this threshold we employ standard Monte Carlo, which results in a hybrid transport-diffusion scheme. With a set of frequency-dependent test problems, we confirm the accuracy and increased efficiency of our new DDMC method.
The hybrid Monte Carlo Algorithm and the chiral transition
Gupta, R.
1987-01-01
In this talk the author describes tests of the Hybrid Monte Carlo Algorithm for QCD done in collaboration with Greg Kilcup and Stephen Sharpe. We find that the acceptance in the glubal Metropolis step for Staggered fermions can be tuned and kept large without having to make the step-size prohibitively small. We present results for the finite temperature transition on 4/sup 4/ and 4 x 6/sup 3/ lattices using this algorithm.
Testing trivializing maps in the Hybrid Monte Carlo algorithm
Engel, Georg P.; Schaefer, Stefan
2011-01-01
We test a recent proposal to use approximate trivializing maps in a field theory to speed up Hybrid Monte Carlo simulations. Simulating the CPN?1 model, we find a small improvement with the leading order transformation, which is however compensated by the additional computational overhead. The scaling of the algorithm towards the continuum is not changed. In particular, the effect of the topological modes on the autocorrelation times is studied. PMID:21969733
Monte Carlo Reliability Model for Microwave Monolithic Integrated Circuits
Rubloff, Gary W.
Monte Carlo Reliability Model for Microwave Monolithic Integrated Circuits Aris Christou Materials of the failure rate of each component due to interaction effects of the failed components. The Monte Carlo failure rates become nonconstant. The Monte Carlo technique is an appropriate methodology used to treat
A Primer in Monte Carlo Integration Using Mathcad
ERIC Educational Resources Information Center
Hoyer, Chad E.; Kegerreis, Jeb S.
2013-01-01
The essentials of Monte Carlo integration are presented for use in an upper-level physical chemistry setting. A Mathcad document that aids in the dissemination and utilization of this information is described and is available in the Supporting Information. A brief outline of Monte Carlo integration is given, along with ideas and pedagogy for…
A Classroom Note on Monte Carlo Integration.
ERIC Educational Resources Information Center
Kolpas, Sid
1998-01-01
The Monte Carlo method provides approximate solutions to a variety of mathematical problems by performing random sampling simulations with a computer. Presents a program written in Quick BASIC simulating the steps of the Monte Carlo method. (ASK)
Bayesian Training of Backpropagation Networks by the Hybrid Monte Carlo Method
Radford Neal
1993-01-01
. It is shown that Bayesian training of backpropagation neural networks can feasiblybe performed by the "Hybrid Monte Carlo" method. This approach allows the true predictivedistribution for a test case given a set of training cases to be approximated arbitrarily closely,in contrast to previous approaches which approximate the posterior weight distribution by aGaussian. In this work, the Hybrid Monte Carlo
Bayesian Inference in Econometric Models Using Monte Carlo Integration
John Geweke
1989-01-01
Methods for the systematic application of Monte Carlo integration with importance sampling to Bayesian inference are developed. Conditions under which the numerical approximation converges almost surely to the true value with the number of Monte Carlo replications, and its numerical accuracy may be assessed reliably, are given. Importance sampling densities are derived from multivariate normal or student approximations to the
A Monte Carlo method for high dimensional integration
Yosihiko Ogata
1989-01-01
Summary A new method for the numerical integration of very high dimensional functions is introduced and implemented based on the Metropolis' Monte Carlo algorithm. The logarithm of the high dimensional integral is reduced to a 1-dimensional integration of a certain statistical function with respect to a scale parameter over the range of the unit interval. The improvement in accuracy is
Integrated high speed hybrid silicon transmitter
NASA Astrophysics Data System (ADS)
Jain, Siddharth R.; Tang, Yongbo; Srinivasan, Sudharsanan; Heck, Martijn J. R.; Bowers, John E.
2013-02-01
We review recent progress made on the hybrid silicon platform towards realizing an integrated high speed WDM transmitter on silicon. Using ion implantation enhanced quantum well intermixing, four band gaps are integrated on a single chip and used to demonstrate a DFB laser array operating over 200 nm from 1250 to 1450 nm. Results from an independent effort to improve on hybrid silicon EA modulator performance are also described. Together these demonstrations pave the way to realize a terabit transmitter on silicon.
ITER Neutronics Modeling Using Hybrid Monte Carlo/Deterministic and CAD-Based Monte Carlo Methods
Ibrahim, A. [University of Wisconsin; Mosher, Scott W [ORNL; Evans, Thomas M [ORNL; Peplow, Douglas E. [ORNL; Sawan, M. [University of Wisconsin; Wilson, P. [University of Wisconsin; Wagner, John C [ORNL; Heltemes, Thad [University of Wisconsin, Madison
2011-01-01
The immense size and complex geometry of the ITER experimental fusion reactor require the development of special techniques that can accurately and efficiently perform neutronics simulations with minimal human effort. This paper shows the effect of the hybrid Monte Carlo (MC)/deterministic techniques - Consistent Adjoint Driven Importance Sampling (CADIS) and Forward-Weighted CADIS (FW-CADIS) - in enhancing the efficiency of the neutronics modeling of ITER and demonstrates the applicability of coupling these methods with computer-aided-design-based MC. Three quantities were calculated in this analysis: the total nuclear heating in the inboard leg of the toroidal field coils (TFCs), the prompt dose outside the biological shield, and the total neutron and gamma fluxes over a mesh tally covering the entire reactor. The use of FW-CADIS in estimating the nuclear heating in the inboard TFCs resulted in a factor of ~ 275 increase in the MC figure of merit (FOM) compared with analog MC and a factor of ~ 9 compared with the traditional methods of variance reduction. By providing a factor of ~ 21 000 increase in the MC FOM, the radiation dose calculation showed how the CADIS method can be effectively used in the simulation of problems that are practically impossible using analog MC. The total flux calculation demonstrated the ability of FW-CADIS to simultaneously enhance the MC statistical precision throughout the entire ITER geometry. Collectively, these calculations demonstrate the ability of the hybrid techniques to accurately model very challenging shielding problems in reasonable execution times.
Wu, Zhigang
Quantum Monte Carlo calculations of the energy-level alignment at hybrid interfaces: Role of many-level alignment at hybrid interfaces, using quantum Monte Carlo calculations to include many-body effects parameters. Here we present a scheme based on the quantum Monte Carlo QMC method18 to obtain accurate energy-lev
Path Integral Monte-Carlo Calculations for Relativistic Oscillator
Alexandr Ivanov; Oleg Pavlovsky
2014-11-11
The problem of Relativistic Oscillator has been studied in the framework of Path Integral Monte-Carlo(PIMC) approach. Ultra-relativistic and non-relativistic limits have been discussed. We show that PIMC method can be effectively used for investigation of relativistic systems.
Hybrid manufacturing : integrating direct write and sterolithography
Donald W. Davis; Asim Inamdar; Amit Lopes; Bart D. Chavez; Phillip L. Gallegos; Jeremy Andrew Palmer; Ryan B. Wicker; Francisco Medina; Robert E. Hennessey
2005-01-01
A commercial stereolithography (SL) machine was modified to integrate fluid dispensing or direct-write (DW) technology with SL in an integrated manufacturing environment for automated and efficient hybrid manufacturing of complex electrical devices, combining three-dimensional (3D) electrical circuitry with SL-manufactured parts. The modified SL system operates similarly to a commercially available machine, although build interrupts were used to stop and start
Path integral Monte Carlo and the electron gas
NASA Astrophysics Data System (ADS)
Brown, Ethan W.
Path integral Monte Carlo is a proven method for accurately simulating quantum mechanical systems at finite-temperature. By stochastically sampling Feynman's path integral representation of the quantum many-body density matrix, path integral Monte Carlo includes non-perturbative effects like thermal fluctuations and particle correlations in a natural way. Over the past 30 years, path integral Monte Carlo has been successfully employed to study the low density electron gas, high-pressure hydrogen, and superfluid helium. For systems where the role of Fermi statistics is important, however, traditional path integral Monte Carlo simulations have an exponentially decreasing efficiency with decreased temperature and increased system size. In this thesis, we work towards improving this efficiency, both through approximate and exact methods, as specifically applied to the homogeneous electron gas. We begin with a brief overview of the current state of atomic simulations at finite-temperature before we delve into a pedagogical review of the path integral Monte Carlo method. We then spend some time discussing the one major issue preventing exact simulation of Fermi systems, the sign problem. Afterwards, we introduce a way to circumvent the sign problem in PIMC simulations through a fixed-node constraint. We then apply this method to the homogeneous electron gas at a large swatch of densities and temperatures in order to map out the warm-dense matter regime. The electron gas can be a representative model for a host of real systems, from simple medals to stellar interiors. However, its most common use is as input into density functional theory. To this end, we aim to build an accurate representation of the electron gas from the ground state to the classical limit and examine its use in finite-temperature density functional formulations. The latter half of this thesis focuses on possible routes beyond the fixed-node approximation. As a first step, we utilize the variational principle inherent in the path integral Monte Carlo method to optimize the nodal surface. By using a ansatz resembling a free particle density matrix, we make a unique connection between a nodal effective mass and the traditional effective mass of many-body quantum theory. We then propose and test several alternate nodal ansatzes and apply them to single atomic systems. Finally, we propose a method to tackle the sign problem head on, by leveraging the relatively simple structure of permutation space. Using this method, we find we can perform exact simulations this of the electron gas and 3He that were previously impossible.
A new optimal Monte Carlo method for calculating integrals of smooth functions #
Dimov, Ivan
A new optimal Monte Carlo method for calculating integrals of smooth functions # Emanouil I. Atanassov 1 , Ivan T. Dimov 1 , Abstract An optimal Monte Carlo method for numerical integration of multi#ciency of the algorithms are also given. Keywords: Monte Carlo method, optimal quadrature formula, rate of convergence. ASM
The S/sub N//Monte Carlo response matrix hybrid method
Filippone, W.L.; Alcouffe, R.E.
1987-01-01
A hybrid method has been developed to iteratively couple S/sub N/ and Monte Carlo regions of the same problem. This technique avoids many of the restrictions and limitations of previous attempts to do the coupling and results in a general and relatively efficient method. We demonstrate the method with some simple examples.
A path integral Monte Carlo method for Rényi entanglement entropies
C. M. Herdman; Stephen Inglis; P. -N. Roy; R. G. Melko; A. Del Maestro
2014-08-04
We introduce a quantum Monte Carlo algorithm to measure the R\\'enyi entanglement entropies in systems of interacting bosons in the continuum. This approach is based on a path integral ground state method that can be applied to interacting itinerant bosons in any spatial dimension with direct relevance to experimental systems of quantum fluids. We demonstrate how it may be used to compute spatial mode entanglement, particle partitioned entanglement, and the entanglement of particles, providing insights into quantum correlations generated by fluctuations, indistinguishability and interactions. We present proof-of-principle calculations, and benchmark against an exactly soluble model of interacting bosons in one spatial dimension. As this algorithm retains the fundamental polynomial scaling of quantum Monte Carlo when applied to sign-problem-free models, future applications should allow for the study of entanglement entropy in large scale many-body systems of interacting bosons.
Monte Carlo Integration Using Spatial Structure of Markov Random Field
NASA Astrophysics Data System (ADS)
Yasuda, Muneki
2015-03-01
Monte Carlo integration (MCI) techniques are important in various fields. In this study, a new MCI technique for Markov random fields (MRFs) is proposed. MCI consists of two successive parts: the first involves sampling using a technique such as the Markov chain Monte Carlo method, and the second involves an averaging operation using the obtained sample points. In the averaging operation, a simple sample averaging technique is often employed. The method proposed in this paper improves the averaging operation by addressing the spatial structure of the MRF and is mathematically guaranteed to statistically outperform standard MCI using the simple sample averaging operation. Moreover, the proposed method can be improved in a systematic manner and is numerically verified by numerical simulations using planar Ising models. In the latter part of this paper, the proposed method is applied to the inverse Ising problem and we observe that it outperforms the maximum pseudo-likelihood estimation.
A Quasi-Monte Carlo Method for Integration with Improved Convergence
Karaivanova, Aneta
A Quasi-Monte Carlo Method for Integration with Improved Convergence Aneta Karaivanova, Ivan Dimov anet@copern.bas.bg, ivdimov@bas.bg, sofia@copern.bas.bg Abstract. Quasi-Monte Carlo methods are based of random numbers with a more uniformly distributed de- terministic sequence. Quasi-Monte Carlo methods
Ibrahim, Ahmad M [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Peterson, Joshua L [ORNL] [ORNL; Grove, Robert E [ORNL] [ORNL
2013-01-01
The rigorous 2-step (R2S) method uses three-dimensional Monte Carlo transport simulations to calculate the shutdown dose rate (SDDR) in fusion reactors. Accurate full-scale R2S calculations are impractical in fusion reactors because they require calculating space- and energy-dependent neutron fluxes everywhere inside the reactor. The use of global Monte Carlo variance reduction techniques was suggested for accelerating the neutron transport calculation of the R2S method. The prohibitive computational costs of these approaches, which increase with the problem size and amount of shielding materials, inhibit their use in the accurate full-scale neutronics analyses of fusion reactors. This paper describes a novel hybrid Monte Carlo/deterministic technique that uses the Consistent Adjoint Driven Importance Sampling (CADIS) methodology but focuses on multi-step shielding calculations. The Multi-Step CADIS (MS-CADIS) method speeds up the Monte Carlo neutron calculation of the R2S method using an importance function that represents the importance of the neutrons to the final SDDR. Using a simplified example, preliminarily results showed that the use of MS-CADIS enhanced the efficiency of the neutron Monte Carlo simulation of an SDDR calculation by a factor of 550 compared to standard global variance reduction techniques, and that the increase over analog Monte Carlo is higher than 10,000.
Finite element model updating using the shadow hybrid Monte Carlo technique
NASA Astrophysics Data System (ADS)
Boulkaibet, I.; Mthembu, L.; Marwala, T.; Friswell, M. I.; Adhikari, S.
2015-02-01
Recent research in the field of finite element model updating (FEM) advocates the adoption of Bayesian analysis techniques to dealing with the uncertainties associated with these models. However, Bayesian formulations require the evaluation of the Posterior Distribution Function which may not be available in analytical form. This is the case in FEM updating. In such cases sampling methods can provide good approximations of the Posterior distribution when implemented in the Bayesian context. Markov Chain Monte Carlo (MCMC) algorithms are the most popular sampling tools used to sample probability distributions. However, the efficiency of these algorithms is affected by the complexity of the systems (the size of the parameter space). The Hybrid Monte Carlo (HMC) offers a very important MCMC approach to dealing with higher-dimensional complex problems. The HMC uses the molecular dynamics (MD) steps as the global Monte Carlo (MC) moves to reach areas of high probability where the gradient of the log-density of the Posterior acts as a guide during the search process. However, the acceptance rate of HMC is sensitive to the system size as well as the time step used to evaluate the MD trajectory. To overcome this limitation we propose the use of the Shadow Hybrid Monte Carlo (SHMC) algorithm. The SHMC algorithm is a modified version of the Hybrid Monte Carlo (HMC) and designed to improve sampling for large-system sizes and time steps. This is done by sampling from a modified Hamiltonian function instead of the normal Hamiltonian function. In this paper, the efficiency and accuracy of the SHMC method is tested on the updating of two real structures; an unsymmetrical H-shaped beam structure and a GARTEUR SM-AG19 structure and is compared to the application of the HMC algorithm on the same structures.
Hybrid Body Representation for Integrated Pose Recognition, Localization and Segmentation
Fan, Guoliang
of human body shapes and poses as well as the in- herent ambiguity in the observed image. Our goal is to de integrated framework. We propose a hybrid body representation, as shown in Fig. 1, where the four images showHybrid Body Representation for Integrated Pose Recognition, Localization and Segmentation Cheng
Hybrid Monte Carlo with Wilson Dirac operator on the Fermi GPU
Abhijit Chakrabarty; Pushan Majumdar
2012-07-10
In this article we present our implementation of a Hybrid Monte Carlo algorithm for Lattice Gauge Theory using two degenerate flavours of Wilson-Dirac fermions on a Fermi GPU. We find that using registers instead of global memory speeds up the code by almost an order of magnitude. To map the array variables to scalars, so that the compiler puts them in the registers, we use code generators. Our final program is more than 10 times faster than a generic single CPU.
When Are Quasi-Monte Carlo Algorithms Efficient for High Dimensional Integrals?
Ian H. Sloan; Henryk Wozniakowski
1998-01-01
Recently, quasi-Monte Carlo algorithms have been successfully used for multivariate integration of high dimensiond, and were significantly more efficient than Monte Carlo algorithms. The existing theory of the worst case error bounds of quasi-Monte Carlo algorithms does not explain this phenomenon. This paper presents a partial answer to why quasi-Monte Carlo algorithms can work well for arbitrarily larged. It is
Path Integral Monte Carlo Calculation of Interatomic Forces
NASA Astrophysics Data System (ADS)
Zong, Fenghua; Ceperley, David
1997-03-01
The calculation of electronic forces with quantum Monte Carlo has, for many years, been an outstanding problem. One can calculate interatomic forces with Path Integral Monte Carlo(PIMC) as the coordinate derivatives of the partition function. Advantages of using PIMC are that effects of thermal electronic excitations and correlations are included, no trial functions are involved and the force estimator is local. We have calculated the classical forces of small molecular systems such as H_2, H_3^+ and H3 determined the bond lengths of H2 and H_3^+, and the saddle point position of the reaction H+H2 --> H_2+H. All are in very good agreement with previous zero temperature calculations. We are applying this method to study the hydrogen-hydrogen interaction in an electron gas as a simple model of hydrogen impurities in metals. Previous LDA calculations are accurate when the H2 molecular binding is dominant but the accuracy is unclear when bound states form at lower density.
Hydrogen molecule ion: Path-integral Monte Carlo approach
Kylaenpaeae, I.; Leino, M.; Rantala, T. T. [Institute of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland)
2007-11-15
The path-integral Monte Carlo approach is used to study the coupled quantum dynamics of the electron and nuclei in hydrogen molecule ion. The coupling effects are demonstrated by comparing differences in adiabatic Born-Oppenheimer and nonadiabatic simulations, and inspecting projections of the full three-body dynamics onto the adiabatic Born-Oppenheimer approximation. Coupling of the electron and nuclear quantum dynamics is clearly seen. The nuclear pair correlation function is found to broaden by 0.040a{sub 0}, and the average bond length is larger by 0.056a{sub 0}. Also, a nonadiabatic correction to the binding energy is found. The electronic distribution is affected less than the nuclear one upon inclusion of nonadiabatic effects.
Monte Carlo Simulations of Background Spectra in Integral Imager Detectors
NASA Technical Reports Server (NTRS)
Armstrong, T. W.; Colborn, B. L.; Dietz, K. L.; Ramsey, B. D.; Weisskopf, M. C.
1998-01-01
Predictions of the expected gamma-ray backgrounds in the ISGRI (CdTe) and PiCsIT (Csl) detectors on INTEGRAL due to cosmic-ray interactions and the diffuse gamma-ray background have been made using a coupled set of Monte Carlo radiation transport codes (HETC, FLUKA, EGS4, and MORSE) and a detailed, 3-D mass model of the spacecraft and detector assemblies. The simulations include both the prompt background component from induced hadronic and electromagnetic cascades and the delayed component due to emissions from induced radioactivity. Background spectra have been obtained with and without the use of active (BGO) shielding and charged particle rejection to evaluate the effectiveness of anticoincidence counting on background rejection.
Irbäck, Anders
Hybrid Monte Carlo simulation of polymer chains A. It-b&k Department of Theoretical Physics) We develop the hybrid Monte Carlo method for simulations of single off-lattice polymer chains. We(ln N)-". 1. INTRODUCTION Monte Carlo methods is a well-established tool in the study of polymer models
NASA Astrophysics Data System (ADS)
Chen, Yunjie; Roux, Benoît
2015-01-01
A family of hybrid simulation methods that combines the advantages of Monte Carlo (MC) with the strengths of classical molecular dynamics (MD) consists in carrying out short non-equilibrium MD (neMD) trajectories to generate new configurations that are subsequently accepted or rejected via an MC process. In the simplest case where a deterministic dynamic propagator is used to generate the neMD trajectories, the familiar Metropolis acceptance criterion based on the change in the total energy ?E, min[1, exp{ - ??E}], guarantees that the hybrid algorithm will yield the equilibrium Boltzmann distribution. However, the functional form of the acceptance probability is more complex when the non-equilibrium switching process is generated via a non-deterministic stochastic dissipative propagator coupled to a heat bath. Here, we clarify the conditions under which the Metropolis criterion remains valid to rigorously yield a proper equilibrium Boltzmann distribution within hybrid neMD-MC algorithm.
Chen, Yunjie; Roux, Benoît
2015-01-14
A family of hybrid simulation methods that combines the advantages of Monte Carlo (MC) with the strengths of classical molecular dynamics (MD) consists in carrying out short non-equilibrium MD (neMD) trajectories to generate new configurations that are subsequently accepted or rejected via an MC process. In the simplest case where a deterministic dynamic propagator is used to generate the neMD trajectories, the familiar Metropolis acceptance criterion based on the change in the total energy ?E, min[1, exp{-??E}], guarantees that the hybrid algorithm will yield the equilibrium Boltzmann distribution. However, the functional form of the acceptance probability is more complex when the non-equilibrium switching process is generated via a non-deterministic stochastic dissipative propagator coupled to a heat bath. Here, we clarify the conditions under which the Metropolis criterion remains valid to rigorously yield a proper equilibrium Boltzmann distribution within hybrid neMD-MC algorithm. PMID:25591332
CAD-based Monte Carlo Program for Integrated Simulation of Nuclear System SuperMC
NASA Astrophysics Data System (ADS)
Wu, Yican; Song, Jing; Zheng, Huaqing; Sun, Guangyao; Hao, Lijuan; Long, Pengcheng; Hu, Liqin
2014-06-01
Monte Carlo (MC) method has distinct advantages to simulate complicated nuclear systems and is envisioned as routine method for nuclear design and analysis in the future. High fidelity simulation with MC method coupled with multi-physical phenomenon simulation has significant impact on safety, economy and sustainability of nuclear systems. However, great challenges to current MC methods and codes prevent its application in real engineering project. SuperMC is a CAD-based Monte Carlo program for integrated simulation of nuclear system developed by FDS Team, China, making use of hybrid MC-deterministic method and advanced computer technologies. The design aim, architecture and main methodology of SuperMC were presented in this paper. SuperMC2.1, the latest version for neutron, photon and coupled neutron and photon transport calculation, has been developed and validated by using a series of benchmarking cases such as the fusion reactor ITER model and the fast reactor BN-600 model. SuperMC is still in its evolution process toward a general and routine tool for nuclear system. Warning, no authors found for 2014snam.conf06023.
A Hybrid Monte Carlo-Deterministic Method for Global Binary Stochastic Medium Transport Problems
Keady, K P; Brantley, P
2010-03-04
Global deep-penetration transport problems are difficult to solve using traditional Monte Carlo techniques. In these problems, the scalar flux distribution is desired at all points in the spatial domain (global nature), and the scalar flux typically drops by several orders of magnitude across the problem (deep-penetration nature). As a result, few particle histories may reach certain regions of the domain, producing a relatively large variance in tallies in those regions. Implicit capture (also known as survival biasing or absorption suppression) can be used to increase the efficiency of the Monte Carlo transport algorithm to some degree. A hybrid Monte Carlo-deterministic technique has previously been developed by Cooper and Larsen to reduce variance in global problems by distributing particles more evenly throughout the spatial domain. This hybrid method uses an approximate deterministic estimate of the forward scalar flux distribution to automatically generate weight windows for the Monte Carlo transport simulation, avoiding the necessity for the code user to specify the weight window parameters. In a binary stochastic medium, the material properties at a given spatial location are known only statistically. The most common approach to solving particle transport problems involving binary stochastic media is to use the atomic mix (AM) approximation in which the transport problem is solved using ensemble-averaged material properties. The most ubiquitous deterministic model developed specifically for solving binary stochastic media transport problems is the Levermore-Pomraning (L-P) model. Zimmerman and Adams proposed a Monte Carlo algorithm (Algorithm A) that solves the Levermore-Pomraning equations and another Monte Carlo algorithm (Algorithm B) that is more accurate as a result of improved local material realization modeling. Recent benchmark studies have shown that Algorithm B is often significantly more accurate than Algorithm A (and therefore the L-P model) for deep penetration problems such as examined in this paper. In this research, we investigate the application of a variant of the hybrid Monte Carlo-deterministic method proposed by Cooper and Larsen to global deep penetration problems involving binary stochastic media. To our knowledge, hybrid Monte Carlo-deterministic methods have not previously been applied to problems involving a stochastic medium. We investigate two approaches for computing the approximate deterministic estimate of the forward scalar flux distribution used to automatically generate the weight windows. The first approach uses the atomic mix approximation to the binary stochastic medium transport problem and a low-order discrete ordinates angular approximation. The second approach uses the Levermore-Pomraning model for the binary stochastic medium transport problem and a low-order discrete ordinates angular approximation. In both cases, we use Monte Carlo Algorithm B with weight windows automatically generated from the approximate forward scalar flux distribution to obtain the solution of the transport problem.
MODEL DEVELOPMENT FOR INTEGRATED HYBRID ELECTRIC VEHICLE DYNAMIC STABILITY SYSTEMS
Joel R. Anstrom
2003-01-01
This study expanded an existing full car dynamic model (HVOSM.VD2) to enable simulation of electric, hybrid electric, and fuel cell vehicles with integrated vehicle stability systems. A prototype range extending series hybrid vehicle was constructed with independent front wheel drives. A hybrid vehicle stability assist (VSA) algorithm was developed to perform proportional control of yaw rate through left\\/right distribution of
Design of integrated hybrid silicon waveguide optical gyroscope
Bowers, John
Design of integrated hybrid silicon waveguide optical gyroscope Sudharsanan Srinivasan,* Renan a novel highly integrated optical gyroscope using low loss silicon nitride waveguides. By integrating the dependence of sensitivity on sensor area. Â©2014 Optical Society of America OCIS codes: (060.2800) Gyroscopes
Hybrid Silicon Evanescent Photonic Integrated Circuit John E. Bowersa
Bowers, John
Hybrid Silicon Evanescent Photonic Integrated Circuit Technology John E. Bowersa , Alexander W, Israel Email: bowers@ece.ucsb.edu (Invited Paper) Abstract: The hybrid silicon evanescent device platform utilizes III-V gain materials bonded to passive silicon waveguides. In this paper, we discuss this device
Integration Graphs: A Class of Decidable Hybrid Systems
Yonit Kesten; Amir Pnueli; Joseph Sifakis; Sergio Yovine
1992-01-01
. Integration Graphs are a computational model developed inthe attempt to identify simple Hybrid Systems with decidable analysisproblems. We start with the class of constant slope hybrid systems(cshs), in which the right hand side of all differential equations is aninteger constant. We refer to continuous variables whose right hand sideconstants are always 1 as timers. All other continuous variables are
Path integral Monte Carlo calculation of electronic forces
NASA Astrophysics Data System (ADS)
Zong, Fenghua; Ceperley, D. M.
1998-10-01
We describe a method to evaluate electronic forces by path integral Monte Carlo (PIMC) calculation. Electronic correlations, as well as thermal effects, are included naturally in this method. For fermions, a restricted approach is used to avoid the ``sign'' problem. The PIMC force estimator is local and has a finite variance. We applied this method to determine the bond length of H2 and the chemical reaction barrier of H+H2-->H2+H. At low temperature, good agreement is obtained with ground-state calculations. We studied the proton-proton interaction in an electron gas as a simple model for hydrogen impurities in metals. We calculated the force between the two protons at two electronic densities corresponding to Na (rs=3.93) and Al (rs=2.07) using a supercell with 38 electrons. The result is compared to previous calculations. We also studied the effect of temperature on the proton-proton interaction. At very high temperature, our result agrees with the Debye screening of electrons. As temperature decreases, the Debye theory fails both because of the strong degeneracy of electrons and most importantly, the formation of electronic bound states around the protons.
Hybrid Parallel Programming Models for AMR Neutron Monte-Carlo Transport
NASA Astrophysics Data System (ADS)
Dureau, David; Poëtte, Gaël
2014-06-01
This paper deals with High Performance Computing (HPC) applied to neutron transport theory on complex geometries, thanks to both an Adaptive Mesh Refinement (AMR) algorithm and a Monte-Carlo (MC) solver. Several Parallelism models are presented and analyzed in this context, among them shared memory and distributed memory ones such as Domain Replication and Domain Decomposition, together with Hybrid strategies. The study is illustrated by weak and strong scalability tests on complex benchmarks on several thousands of cores thanks to the petaflopic supercomputer Tera100.
NASA Astrophysics Data System (ADS)
Townson, Reid W.; Zavgorodni, Sergei
2014-12-01
In GPU-based Monte Carlo simulations for radiotherapy dose calculation, source modelling from a phase-space source can be an efficiency bottleneck. Previously, this has been addressed using phase-space-let (PSL) sources, which provided significant efficiency enhancement. We propose that additional speed-up can be achieved through the use of a hybrid primary photon point source model combined with a secondary PSL source. A novel phase-space derived and histogram-based implementation of this model has been integrated into gDPM v3.0. Additionally, a simple method for approximately deriving target photon source characteristics from a phase-space that does not contain inheritable particle history variables (LATCH) has been demonstrated to succeed in selecting over 99% of the true target photons with only ~0.3% contamination (for a Varian 21EX 18?MV machine). The hybrid source model was tested using an array of open fields for various Varian 21EX and TrueBeam energies, and all cases achieved greater than 97% chi-test agreement (the mean was 99%) above the 2% isodose with 1% / 1?mm criteria. The root mean square deviations (RMSDs) were less than 1%, with a mean of 0.5%, and the source generation time was 4–5 times faster. A seven-field intensity modulated radiation therapy patient treatment achieved 95% chi-test agreement above the 10% isodose with 1% / 1?mm criteria, 99.8% for 2% / 2?mm, a RMSD of 0.8%, and source generation speed-up factor of 2.5. Presented as part of the International Workshop on Monte Carlo Techniques in Medical Physics
Plug-in integrated/hybrid circuit
NASA Technical Reports Server (NTRS)
Stringer, E. J.
1974-01-01
Hybrid circuitry can be installed into standard round bayonet connectors, to eliminate wiring from connector to circuit. Circuits can be connected directly into either section of connector pair, eliminating need for hard wiring to that section.
A Frequency Analysis of Monte-Carlo and other Numerical Integration Schemes
Durand, Frédo
2011-12-14
The numerical calculation of integrals is central to many computer graphics algorithms such as Monte-Carlo Ray Tracing. We show that such methods can be studied using Fourier analysis. Numerical error is shown to correspond ...
Monte Carlo Methods for Integration A Project for Math 489/889
Dunbar, Steve
Monte Carlo Methods for Integration A Project for Math 489/889 Steven R. Dunbar November 2010.575829304 Using the confidence interval to estimate the required number of trials We desire with probability
Information Integration via Hierarchical and Hybrid Bayesian Networks
Haiying Tu; Jefferey Allanach; Satnam Singh; Krishna R. Pattipati; Peter Willett
2006-01-01
óA collaboration scheme for information integration among multiple agencies (and\\/or various divisions within a single agency) is designed using hierarchical and hybrid Bayesian net- works (HHBNs). In this scheme, raw information is represented by transactions (such as communication, travel, nancing), and information entities to be integrated are modeled as random variables (such as: an event occurs, an effect exists, or
Hybrid Online Education: Identifying Integration Models Using Adventure Learning
ERIC Educational Resources Information Center
Doering, Aaron; Veletsianos, George
2008-01-01
In this paper we sought to understand how teachers chose to integrate a hybrid online education program in their classrooms, how students responded to this choice, and how students' experiences were influenced by the integration model chosen by the teachers. Data collected via classroom observations, personal interviews, and focus groups suggest…
Chen, Yunjie; Roux, Benoît
2014-09-21
Hybrid schemes combining the strength of molecular dynamics (MD) and Metropolis Monte Carlo (MC) offer a promising avenue to improve the sampling efficiency of computer simulations of complex systems. A number of recently proposed hybrid methods consider new configurations generated by driving the system via a non-equilibrium MD (neMD) trajectory, which are subsequently treated as putative candidates for Metropolis MC acceptance or rejection. To obey microscopic detailed balance, it is necessary to alter the momentum of the system at the beginning and/or the end of the neMD trajectory. This strict rule then guarantees that the random walk in configurational space generated by such hybrid neMD-MC algorithm will yield the proper equilibrium Boltzmann distribution. While a number of different constructs are possible, the most commonly used prescription has been to simply reverse the momenta of all the particles at the end of the neMD trajectory ("one-end momentum reversal"). Surprisingly, it is shown here that the choice of momentum reversal prescription can have a considerable effect on the rate of convergence of the hybrid neMD-MC algorithm, with the simple one-end momentum reversal encountering particularly acute problems. In these neMD-MC simulations, different regions of configurational space end up being essentially isolated from one another due to a very small transition rate between regions. In the worst-case scenario, it is almost as if the configurational space does not constitute a single communicating class that can be sampled efficiently by the algorithm, and extremely long neMD-MC simulations are needed to obtain proper equilibrium probability distributions. To address this issue, a novel momentum reversal prescription, symmetrized with respect to both the beginning and the end of the neMD trajectory ("symmetric two-ends momentum reversal"), is introduced. Illustrative simulations demonstrate that the hybrid neMD-MC algorithm robustly yields a correct equilibrium probability distribution with this prescription. PMID:25240345
NASA Astrophysics Data System (ADS)
Chen, Yunjie; Roux, Benoît
2014-09-01
Hybrid schemes combining the strength of molecular dynamics (MD) and Metropolis Monte Carlo (MC) offer a promising avenue to improve the sampling efficiency of computer simulations of complex systems. A number of recently proposed hybrid methods consider new configurations generated by driving the system via a non-equilibrium MD (neMD) trajectory, which are subsequently treated as putative candidates for Metropolis MC acceptance or rejection. To obey microscopic detailed balance, it is necessary to alter the momentum of the system at the beginning and/or the end of the neMD trajectory. This strict rule then guarantees that the random walk in configurational space generated by such hybrid neMD-MC algorithm will yield the proper equilibrium Boltzmann distribution. While a number of different constructs are possible, the most commonly used prescription has been to simply reverse the momenta of all the particles at the end of the neMD trajectory ("one-end momentum reversal"). Surprisingly, it is shown here that the choice of momentum reversal prescription can have a considerable effect on the rate of convergence of the hybrid neMD-MC algorithm, with the simple one-end momentum reversal encountering particularly acute problems. In these neMD-MC simulations, different regions of configurational space end up being essentially isolated from one another due to a very small transition rate between regions. In the worst-case scenario, it is almost as if the configurational space does not constitute a single communicating class that can be sampled efficiently by the algorithm, and extremely long neMD-MC simulations are needed to obtain proper equilibrium probability distributions. To address this issue, a novel momentum reversal prescription, symmetrized with respect to both the beginning and the end of the neMD trajectory ("symmetric two-ends momentum reversal"), is introduced. Illustrative simulations demonstrate that the hybrid neMD-MC algorithm robustly yields a correct equilibrium probability distribution with this prescription.
Hybrid Monte Carlo/Deterministic Methods for Accelerating Active Interrogation Modeling
Peplow, Douglas E. [ORNL; Miller, Thomas Martin [ORNL; Patton, Bruce W [ORNL; Wagner, John C [ORNL
2013-01-01
The potential for smuggling special nuclear material (SNM) into the United States is a major concern to homeland security, so federal agencies are investigating a variety of preventive measures, including detection and interdiction of SNM during transport. One approach for SNM detection, called active interrogation, uses a radiation source, such as a beam of neutrons or photons, to scan cargo containers and detect the products of induced fissions. In realistic cargo transport scenarios, the process of inducing and detecting fissions in SNM is difficult due to the presence of various and potentially thick materials between the radiation source and the SNM, and the practical limitations on radiation source strength and detection capabilities. Therefore, computer simulations are being used, along with experimental measurements, in efforts to design effective active interrogation detection systems. The computer simulations mostly consist of simulating radiation transport from the source to the detector region(s). Although the Monte Carlo method is predominantly used for these simulations, difficulties persist related to calculating statistically meaningful detector responses in practical computing times, thereby limiting their usefulness for design and evaluation of practical active interrogation systems. In previous work, the benefits of hybrid methods that use the results of approximate deterministic transport calculations to accelerate high-fidelity Monte Carlo simulations have been demonstrated for source-detector type problems. In this work, the hybrid methods are applied and evaluated for three example active interrogation problems. Additionally, a new approach is presented that uses multiple goal-based importance functions depending on a particle s relevance to the ultimate goal of the simulation. Results from the examples demonstrate that the application of hybrid methods to active interrogation problems dramatically increases their calculational efficiency.
Advances in hybrid organic\\/inorganic optoelectronic integration
Louay A. Eldada; Antonije M. Radojevic; Junichiro Fujita; Tomoyuki Izuhara; Reinald Gerhardt
2004-01-01
We report on advances in the hybrid organic\\/inorganic integration of passive and active optical functions. The integration approaches include chip-to-chip attach, flip-chip mounting, and insertion of films in slots formed in planar lightwave circuits. The materials integrated include polymer, silica, silicon, silicon oxynitride, lithium niobate, indium phosphide, gallium arsenide, yttrium iron garnet, and neodymium iron boron. The functions enabled by
Lazy skip-lists: An algorithm for fast hybridization-expansion quantum Monte Carlo
NASA Astrophysics Data System (ADS)
Sémon, P.; Yee, Chuck-Hou; Haule, Kristjan; Tremblay, A.-M. S.
2014-08-01
The solution of a generalized impurity model lies at the heart of electronic structure calculations with dynamical mean field theory. In the strongly correlated regime, the method of choice for solving the impurity model is the hybridization-expansion continuous-time quantum Monte Carlo (CT-HYB). Enhancements to the CT-HYB algorithm are critical for bringing new physical regimes within reach of current computational power. Taking advantage of the fact that the bottleneck in the algorithm is a product of hundreds of matrices, we present optimizations based on the introduction and combination of two concepts of more general applicability: (a) skip lists and (b) fast rejection of proposed configurations based on matrix bounds. Considering two very different test cases with d electrons, we find speedups of ˜25 up to ˜500 compared to the direct evaluation of the matrix product. Even larger speedups are likely with f electron systems and with clusters of correlated atoms.
Feasibility of a Monte Carlo-deterministic hybrid method for fast reactor analysis
Heo, W.; Kim, W.; Kim, Y. [Korea Advanced Institute of Science and Technology - KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Yun, S. [Korea Atomic Energy Research Institute - KAERI, 989-111 Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)
2013-07-01
A Monte Carlo and deterministic hybrid method is investigated for the analysis of fast reactors in this paper. Effective multi-group cross sections data are generated using a collision estimator in the MCNP5. A high order Legendre scattering cross section data generation module was added into the MCNP5 code. Both cross section data generated from MCNP5 and TRANSX/TWODANT using the homogeneous core model were compared, and were applied to DIF3D code for fast reactor core analysis of a 300 MWe SFR TRU burner core. For this analysis, 9 groups macroscopic-wise data was used. In this paper, a hybrid calculation MCNP5/DIF3D was used to analyze the core model. The cross section data was generated using MCNP5. The k{sub eff} and core power distribution were calculated using the 54 triangle FDM code DIF3D. A whole core calculation of the heterogeneous core model using the MCNP5 was selected as a reference. In terms of the k{sub eff}, 9-group MCNP5/DIF3D has a discrepancy of -154 pcm from the reference solution, 9-group TRANSX/TWODANT/DIF3D analysis gives -1070 pcm discrepancy. (authors)
Townson, Reid W; Zavgorodni, Sergei
2014-11-26
In GPU-based Monte Carlo simulations for radiotherapy dose calculation, source modelling from a phase-space source can be an efficiency bottleneck. Previously, this has been addressed using phase-space-let (PSL) sources, which provided significant efficiency enhancement. We propose that additional speed-up can be achieved through the use of a hybrid primary photon point source model combined with a secondary PSL source. A novel phase-space derived and histogram-based implementation of this model has been integrated into gDPM v3.0. Additionally, a simple method for approximately deriving target photon source characteristics from a phase-space that does not contain inheritable particle history variables (LATCH) has been demonstrated to succeed in selecting over 99% of the true target photons with only ~0.3% contamination (for a Varian 21EX 18?MV machine). The hybrid source model was tested using an array of open fields for various Varian 21EX and TrueBeam energies, and all cases achieved greater than 97% chi-test agreement (the mean was 99%) above the 2% isodose with 1% / 1?mm criteria. The root mean square deviations (RMSDs) were less than 1%, with a mean of 0.5%, and the source generation time was 4-5 times faster. A seven-field intensity modulated radiation therapy patient treatment achieved 95% chi-test agreement above the 10% isodose with 1% / 1?mm criteria, 99.8% for 2% / 2?mm, a RMSD of 0.8%, and source generation speed-up factor of 2.5. PMID:25426972
Improved Hybrid Monte Carlo/n-Moment Transport Equations Model for the Polar Wind
NASA Astrophysics Data System (ADS)
Barakat, A. R.; Ji, J.; Schunk, R. W.
2013-12-01
In many space plasma problems (e.g. terrestrial polar wind, solar wind, etc.), the plasma gradually evolves from dense collision-dominated into rarified collisionless conditions. For decades, numerous attempts were made in order to address this type of problem using simulations based on one of two approaches. These approaches are: (1) the (fluid-like) Generalized Transport Equations, GTE, and (2) the particle-based Monte Carlo (MC) techniques. In contrast to the computationally intensive MC, the GTE approach can be considerably more efficient but its validity is questionable outside the collision-dominated region depending on the number of transport parameters considered. There have been several attempts to develop hybrid models that combine the strengths of both approaches. In particular, low-order GTE formulations were applied within the collision-dominated region, while an MC simulation was applied within the collisionless region and in the collisional-to-collisionless transition region. However, attention must be paid to assuring the consistency of the two approaches in the region where they are matched. Contrary to all previous studies, our model pays special attention to the ';matching' issue, and hence eliminates the discontinuities/inaccuracies associated with mismatching. As an example, we applied our technique to the Coulomb-Milne problem because of its relevance to the problem of space plasma flow from high- to low-density regions. We will compare the velocity distribution function and its moments (density, flow velocity, temperature, etc.) from the following models: (1) the pure MC model, (2) our hybrid model, and (3) previously published hybrid models. We will also consider a wide range of the test-to-background mass ratio.
Hybrid III-V/silicon SOA for photonic integrated circuits
NASA Astrophysics Data System (ADS)
Kaspar, P.; Brenot, R.; Le Liepvre, A.; Accard, A.; Make, D.; Levaufre, G.; Girard, N.; Lelarge, F.; Duan, G.-H.; Olivier, S.; Jany, Christophe; Kopp, C.; Menezo, S.
2014-11-01
Silicon photonics has reached a considerable level of maturity, and the complexity of photonic integrated circuits (PIC) is steadily increasing. As the number of components in a PIC grows, loss management becomes more and more important. Integrated semiconductor optical amplifiers (SOA) will be crucial components in future photonic systems for loss compensation. In addition, there are specific applications, where SOAs can play a key role beyond mere loss compensation, such as modulated reflective SOAs in carrier distributed passive optical networks or optical gates in packet switching. It is, therefore, highly desirable to find a generic integration platform that includes the possibility of integrating SOAs on silicon. Various methods are currently being developed to integrate light emitters on silicon-on-insulator (SOI) waveguide circuits. Many of them use III-V materials for the hybrid integration on SOI. Various types of lasers have been demonstrated by several groups around the globe. In some of the integration approaches, SOAs can be implemented using essentially the same technology as for lasers. In this paper we will focus on SOA devices based on a hybrid integration approach where III-V material is bonded on SOI and a vertical optical mode transfer is used to couple light between SOI waveguides and guides formed in bonded III-V semiconductor layers. In contrast to evanescent coupling schemes, this mode transfer allows for a higher confinement factor in the gain material and thus for efficient light amplification over short propagation distances. We will outline the fabrication process of our hybrid components and present some of the most interesting results from a fabricated and packaged hybrid SOA.
Fully integrated hybrid silicon two dimensional beam scanner.
Hulme, J C; Doylend, J K; Heck, M J R; Peters, J D; Davenport, M L; Bovington, J T; Coldren, L A; Bowers, J E
2015-03-01
In this work we present the first fully-integrated free-space beam-steering chip using the hybrid silicon platform. The photonic integrated circuit (PIC) consists of 164 optical components including lasers, amplifiers, photodiodes, phase tuners, grating couplers, splitters, and a photonic crystal lens. The PIC exhibited steering over 23° x 3.6° with beam widths of 1° x 0.6°. PMID:25836813
Information integration via hierarchical and hybrid bayesian networks
Haiying Tu; Jeffrey Allanach; Satnam Singh; Krishna R. Pattipati; Peter Willett
2006-01-01
nancing), and information entities to be integrated are modeled as random variables (such as: an event occurs, an effect exists, or an action is undertaken). Each random variable has certain states with probabilities assigned to them. Hierarchical is in terms of the model structure and hybrid stems from our usage of both general Bayesian networks (BNs) and hidden Markov models
High-order path-integral Monte Carlo methods for solving quantum dot problems
NASA Astrophysics Data System (ADS)
Chin, Siu A.
2015-03-01
The conventional second-order path-integral Monte Carlo method is plagued with the sign problem in solving many-fermion systems. This is due to the large number of antisymmetric free-fermion propagators that are needed to extract the ground state wave function at large imaginary time. In this work we show that optimized fourth-order path-integral Monte Carlo methods, which use no more than five free-fermion propagators, can yield accurate quantum dot energies for up to 20 polarized electrons with the use of the Hamiltonian energy estimator.
Integrated Hybrid-Simulation of Electric Power and Communications Systems
Nutaro, James J [ORNL; Kuruganti, Phani Teja [ORNL; Miller, Laurie E [ORNL; Mullen, Sara [ORNL; Shankar, Mallikarjun [ORNL
2007-01-01
The modern power grid is strongly integrated with its communication network. While a power system primarily consists of elements that are modeled by continuous equations, a communication system has discrete event dynamics. We model the integrated operation of these two systems with a hybrid modeling and simulation technique. Systematically combining continuous and discrete event system models is necessary for correctly simulating critical system behaviors. This paper discusses an approach based on the discrete event system specification (DEVS) that characterizes the interaction of the two systems formally to preserve simulation correctness. We demonstrate the implementation of our integrated hybrid simulation technique with detailed generator and network models in a wide-area cooperative automatic load-control scenario.
Integration of the feline radiation hybrid and linkage maps.
Sun, S; Murphy, W J; Menotti-Raymond, M; O'Brien, S J
2001-06-01
The recent development of genome mapping resources for the domestic cat provides a unique opportunity to study comparative medicine in this companion animal which can inform and benefit both veterinary and human biomedical concerns. We describe here the integration and order comparison of the feline radiation hybrid (RH) map with the feline interspecies backcross (ISB) genetic linkage map, constructed by a backcross of F1 hybrids between domestic cat (Felis catus) and the Asian leopard cat (Prionailurus bengalensis). Of 253 microsatellite loci mapped in the ISB, 176 equivalently spaced markers were ordered among a framework of 424 Type I coding markers in the RH map. The integration of the RH and ISB maps resolves the orientation of multiple linkage groups and singleton loci from the ISB genetic map. This integrated map provides the foundation for gene mapping assessments in the domestic cat and in related species of the Felidae family. PMID:11353390
Quirk, Thomas, J., IV (University of New Mexico)
2004-08-01
The Integrated TIGER Series (ITS) is a software package that solves coupled electron-photon transport problems. ITS performs analog photon tracking for energies between 1 keV and 1 GeV. Unlike its deterministic counterpart, the Monte Carlo calculations of ITS do not require a memory-intensive meshing of phase space; however, its solutions carry statistical variations. Reducing these variations is heavily dependent on runtime. Monte Carlo simulations must therefore be both physically accurate and computationally efficient. Compton scattering is the dominant photon interaction above 100 keV and below 5-10 MeV, with higher cutoffs occurring in lighter atoms. In its current model of Compton scattering, ITS corrects the differential Klein-Nishina cross sections (which assumes a stationary, free electron) with the incoherent scattering function, a function dependent on both the momentum transfer and the atomic number of the scattering medium. While this technique accounts for binding effects on the scattering angle, it excludes the Doppler broadening the Compton line undergoes because of the momentum distribution in each bound state. To correct for these effects, Ribbefor's relativistic impulse approximation (IA) will be employed to create scattering cross section differential in both energy and angle for each element. Using the parameterizations suggested by Brusa et al., scattered photon energies and angle can be accurately sampled at a high efficiency with minimal physical data. Two-body kinematics then dictates the electron's scattered direction and energy. Finally, the atomic ionization is relaxed via Auger emission or fluorescence. Future work will extend these improvements in incoherent scattering to compounds and to adjoint calculations.
NASA Astrophysics Data System (ADS)
Whitehead, James Joshua
The analysis documented herein provides an integrated approach for the conduct of optimization under uncertainty (OUU) using Monte Carlo Simulation (MCS) techniques coupled with response surface-based methods for characterization of mixture-dependent variables. This novel methodology provides an innovative means of conducting optimization studies under uncertainty in propulsion system design. Analytic inputs are based upon empirical regression rate information obtained from design of experiments (DOE) mixture studies utilizing a mixed oxidizer hybrid rocket concept. Hybrid fuel regression rate was selected as the target response variable for optimization under uncertainty, with maximization of regression rate chosen as the driving objective. Characteristic operational conditions and propellant mixture compositions from experimental efforts conducted during previous foundational work were combined with elemental uncertainty estimates as input variables. Response surfaces for mixture-dependent variables and their associated uncertainty levels were developed using quadratic response equations incorporating single and two-factor interactions. These analysis inputs, response surface equations and associated uncertainty contributions were applied to a probabilistic MCS to develop dispersed regression rates as a function of operational and mixture input conditions within design space. Illustrative case scenarios were developed and assessed using this analytic approach including fully and partially constrained operational condition sets over all of design mixture space. In addition, optimization sets were performed across an operationally representative region in operational space and across all investigated mixture combinations. These scenarios were selected as representative examples relevant to propulsion system optimization, particularly for hybrid and solid rocket platforms. Ternary diagrams, including contour and surface plots, were developed and utilized to aid in visualization. The concept of Expanded-Durov diagrams was also adopted and adapted to this study to aid in visualization of uncertainty bounds. Regions of maximum regression rate and associated uncertainties were determined for each set of case scenarios. Application of response surface methodology coupled with probabilistic-based MCS allowed for flexible and comprehensive interrogation of mixture and operating design space during optimization cases. Analyses were also conducted to assess sensitivity of uncertainty to variations in key elemental uncertainty estimates. The methodology developed during this research provides an innovative optimization tool for future propulsion design efforts.
Integrated Hybrid System Architecture for Risk Analysis
NASA Technical Reports Server (NTRS)
Moynihan, Gary P.; Fonseca, Daniel J.; Ray, Paul S.
2010-01-01
A conceptual design has been announced of an expert-system computer program, and the development of a prototype of the program, intended for use as a project-management tool. The program integrates schedule and risk data for the purpose of determining the schedule applications of safety risks and, somewhat conversely, the effects of changes in schedules on changes on safety. It is noted that the design has been delivered to a NASA client and that it is planned to disclose the design in a conference presentation.
Polymer waveguide based hybrid opto-electric integration technology
NASA Astrophysics Data System (ADS)
Mao, Jinbin; Deng, Lingling; Jiang, Xiyan; Ren, Rong; Zhai, Yumeng; Wang, Jin
2014-10-01
While monolithic integration especially based on InP appears to be quite an expensive solution for optical devices, hybrid integration solutions using cheaper material platforms are considered powerful competitors because of the high freedom of design, yield optimization and relative cost-efficiency. Among them, the polymer planar-lightwave circuit (PLC) technology is regarded attractive as polymer offers the potential of fairly simple and low-cost fabrication, and of low-cost packaging. In our work, polymer PLC was fabricated by using the standard reactive ion etching (RIE) technique, while other active and passive devices can be integrated on the polymer PLC platform. Exemplary polymer waveguide devices was a 13-channel arrayed waveguide grating (AWG) chip, where the central channel cross-talk was below -30dB and the polarization dependent frequency shift was mitigated by inserting a half wave plate. An optical 900 hybrid was also realized with one 2×4 multi-mode interferometer (MMI). The excess insertion losses are below 4dB for the C-band, while the transmission imbalance is below 1.2dB. When such an optical hybrid was integrated vertically with mesa-type photodiodes, the responsivity of the individual PD was around 0.06 A/W, while the 3 dB bandwidth reaches 24 ~ 27 GHz, which is sufficient for 100Gbit/s receivers. Another example of the hybrid integration was to couple the polymer waveguides to fiber by applying fiber grooves, whose typical loss value was 0.2 dB per-facet over a broad spectral range from 1200-1600 nm.
Path-integral quantum Monte Carlo studies of lattice polarons and bipolarons
NASA Astrophysics Data System (ADS)
Kornilovitch, Pavel
2008-05-01
A path-integral Quantum Monte Carlo method for lattice polaron and bipolaron is presented. Analytical integration eliminates the phonons exactly leading to one or two self-interacting imaginary-time trajectories, which are then simulated by Metropolis Monte Carlo. Projection operators separate states of different symmetry, which provides access to various excited states such as the polaron energy, spectrum, effective mass, density of states and singlet-triplet bipolaron splitting. Monte Carlo updates are formulated in continuous imaginary time on infinite lattices and as such provide statistically unbiased results without finite-size and finite time-step errors. Numerical data are presented for models with short-range and long-range electron--phonon interactions. It is shown that a long-range electron-phonon interaction dramatically reduces the polaron and bipolaron mass, potentially leading to a high critical temperature of the bipolaronic superconductor.
Bousige, Colin; Bo?an, Alexandru; Ulm, Franz-Josef; Pellenq, Roland J-M; Coasne, Benoît
2015-03-21
We report an efficient atom-scale reconstruction method that consists of combining the Hybrid Reverse Monte Carlo algorithm (HRMC) with Molecular Dynamics (MD) in the framework of a simulated annealing technique. In the spirit of the experimentally constrained molecular relaxation technique [Biswas et al., Phys. Rev. B 69, 195207 (2004)], this modified procedure offers a refined strategy in the field of reconstruction techniques, with special interest for heterogeneous and disordered solids such as amorphous porous materials. While the HRMC method generates physical structures, thanks to the use of energy penalties, the combination with MD makes the method at least one order of magnitude faster than HRMC simulations to obtain structures of similar quality. Furthermore, in order to ensure the transferability of this technique, we provide rational arguments to select the various input parameters such as the relative weight ? of the energy penalty with respect to the structure optimization. By applying the method to disordered porous carbons, we show that adsorption properties provide data to test the global texture of the reconstructed sample but are only weakly sensitive to the presence of defects. In contrast, the vibrational properties such as the phonon density of states are found to be very sensitive to the local structure of the sample. PMID:25796236
NASA Astrophysics Data System (ADS)
Bousige, Colin; BoÅ£an, Alexandru; Ulm, Franz-Josef; Pellenq, Roland J.-M.; Coasne, Benoît
2015-03-01
We report an efficient atom-scale reconstruction method that consists of combining the Hybrid Reverse Monte Carlo algorithm (HRMC) with Molecular Dynamics (MD) in the framework of a simulated annealing technique. In the spirit of the experimentally constrained molecular relaxation technique [Biswas et al., Phys. Rev. B 69, 195207 (2004)], this modified procedure offers a refined strategy in the field of reconstruction techniques, with special interest for heterogeneous and disordered solids such as amorphous porous materials. While the HRMC method generates physical structures, thanks to the use of energy penalties, the combination with MD makes the method at least one order of magnitude faster than HRMC simulations to obtain structures of similar quality. Furthermore, in order to ensure the transferability of this technique, we provide rational arguments to select the various input parameters such as the relative weight ? of the energy penalty with respect to the structure optimization. By applying the method to disordered porous carbons, we show that adsorption properties provide data to test the global texture of the reconstructed sample but are only weakly sensitive to the presence of defects. In contrast, the vibrational properties such as the phonon density of states are found to be very sensitive to the local structure of the sample.
Abdel-Khalik, Hany S.; Gardner, Robin; Mattingly, John; Sood, Avneet
2014-05-20
The development of hybrid Monte-Carlo-Deterministic (MC-DT) approaches, taking place over the past few decades, have primarily focused on shielding and detection applications where the analysis requires a small number of responses, i.e. at the detector locations(s). This work further develops a recently introduced global variance reduction approach, denoted by the SUBSPACE approach is designed to allow the use of MC simulation, currently limited to benchmarking calculations, for routine engineering calulations. By way of demonstration, the SUBSPACE approach is applied to assembly level calculations used to generate the few-group homogenized cross-sections. These models are typically expensive and need to be executed in the order of 10-10 times to properly characterize the few-group cross-sections for deownstream core-wide calculations. Applicability to k-eigenvalue core-wide models is also demonstrated in this work. Given the faborable results obtained in this work, we believe the applicability of the MC method for reactor analysis calculations could be realized in the near future.
Hybrid integrated photonic components based on a polymer platform
Louay Eldada
We report on a polymer-on-silicon optical bench platform that enables the hybrid integration of elemental passive and active optical functions. Planar polymer circuits are produced photolithographically, and slots are formed in them for the insertion of chips and films of a variety of materials. The polymer circuits provide interconnects, static routing elements such as couplers, taps, and multi\\/demultiplexers, as well
Integration mechanism for a parallel hybrid vehicle system
K. David Huang; Sheng-Chung Tzeng; Tzer-Ming Jeng; Chia-Chang Chen
2005-01-01
The parallel hybrid-vehicle system discussed here features two mechanisms: an internal-combustion-engine energy-distribution mechanism and dual energy-integration mechanism. The former comprises a first pulley set and a second pulley set, whereby it is possible to adjust its radius ratio and change the road surface oriented output load, output speed and required load, to maintain an optimal operating state for the internal-combustion
Kaoru Aoki; Shigetaka Kuroda; Shigemasa Kajiwara; Hiromitsu Sato; Yoshio Yamamoto
2000-06-19
This paper presents the technical approach used to design and develop the powerplant for the Honda Insight, a new motor assist hybrid vehicle with an overall development objective of just half the fuel consumption of the current Civic over a wide range of driving conditions. Fuel consumption of 35km/L (Japanese 10-15 mode), and 3.4L/100km (98/69/EC) was realized. To achieve this, a new Integrated Motor Assist (IMA) hybrid power plant system was developed, incorporating many new technologies for packaging and integrating the motor assist system and for improving engine thermal efficiency. This was developed in combination with a new lightweight aluminum body with low aerodynamic resistance. Environmental performance goals also included the simultaneous achievement of low emissions (half the Japanese year 2000 standards, and half the EU2000 standards), high efficiency, and recyclability. Full consideration was also given to key consumer attributes, including crash safety performance, handling, and driving performance.
HRMC_1.1: Hybrid Reverse Monte Carlo method with silicon and carbon potentials
NASA Astrophysics Data System (ADS)
Opletal, G.; Petersen, T. C.; O'Malley, B.; Snook, I. K.; McCulloch, D. G.; Yarovsky, I.
2011-02-01
The Hybrid Reverse Monte Carlo (HRMC) code models the atomic structure of materials via the use of a combination of constraints including experimental diffraction data and an empirical energy potential. This energy constraint is in the form of either the Environment Dependent Interatomic Potential (EDIP) for carbon and silicon and the original and modified Stillinger-Weber potentials applicable to silicon. In this version, an update is made to correct an error in the EDIP carbon energy calculation routine. New version program summaryProgram title: HRMC version 1.1 Catalogue identifier: AEAO_v1_1 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAO_v1_1.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 36 991 No. of bytes in distributed program, including test data, etc.: 907 800 Distribution format: tar.gz Programming language: FORTRAN 77 Computer: Any computer capable of running executables produced by the g77 Fortran compiler. Operating system: Unix, Windows RAM: Depends on the type of empirical potential use, number of atoms and which constraints are employed. Classification: 7.7 Catalogue identifier of previous version: AEAO_v1_0 Journal reference of previous version: Comput. Phys. Comm. 178 (2008) 777 Does the new version supersede the previous version?: Yes Nature of problem: Atomic modelling using empirical potentials and experimental data. Solution method: Monte Carlo Reasons for new version: An error in a term associated with the calculation of energies using the EDIP carbon potential which results in incorrect energies. Summary of revisions: Fix to correct brackets in the two body part of the EDIP carbon potential routine. Additional comments: The code is not standard FORTRAN 77 but includes some additional features and therefore generates errors when compiled using the Nag95 compiler. It does compile successfully with the GNU g77 compiler ( http://www.gnu.org/software/fortran/fortran.html). Running time: Depends on the type of empirical potential use, number of atoms and which constraints are employed. The test included in the distribution took 37 minutes on a DEC Alpha PC.
Path integrals and large deviations in stochastic hybrid systems
NASA Astrophysics Data System (ADS)
Bressloff, Paul C.; Newby, Jay M.
2014-04-01
We construct a path-integral representation of solutions to a stochastic hybrid system, consisting of one or more continuous variables evolving according to a piecewise-deterministic dynamics. The differential equations for the continuous variables are coupled to a set of discrete variables that satisfy a continuous-time Markov process, which means that the differential equations are only valid between jumps in the discrete variables. Examples of stochastic hybrid systems arise in biophysical models of stochastic ion channels, motor-driven intracellular transport, gene networks, and stochastic neural networks. We use the path-integral representation to derive a large deviation action principle for a stochastic hybrid system. Minimizing the associated action functional with respect to the set of all trajectories emanating from a metastable state (assuming that such a minimization scheme exists) then determines the most probable paths of escape. Moreover, evaluating the action functional along a most probable path generates the so-called quasipotential used in the calculation of mean first passage times. We illustrate the theory by considering the optimal paths of escape from a metastable state in a bistable neural network.
Driver, K P; Militzer, B
2012-03-16
We develop an all-electron path integral Monte Carlo method with free-particle nodes for warm dense matter and apply it to water and carbon plasmas. We thereby extend path integral Monte Carlo studies beyond hydrogen and helium to elements with core electrons. Path integral Monte Carlo results for pressures, internal energies, and pair-correlation functions compare well with density functional theory molecular dynamics calculations at temperatures of (2.5-7.5)×10(5) K, and both methods together form a coherent equation of state over a density-temperature range of 3-12 g/cm(3) and 10(4)-10(9) K. PMID:22540485
Hey, Jody; Nielsen, Rasmus
2007-01-01
In 1988, Felsenstein described a framework for assessing the likelihood of a genetic data set in which all of the possible genealogical histories of the data are considered, each in proportion to their probability. Although not analytically solvable, several approaches, including Markov chain Monte Carlo methods, have been developed to find approximate solutions. Here, we describe an approach in which Markov chain Monte Carlo simulations are used to integrate over the space of genealogies, whereas other parameters are integrated out analytically. The result is an approximation to the full joint posterior density of the model parameters. For many purposes, this function can be treated as a likelihood, thereby permitting likelihood-based analyses, including likelihood ratio tests of nested models. Several examples, including an application to the divergence of chimpanzee subspecies, are provided. PMID:17301231
Enhanced optical forces in integrated hybrid plasmonic waveguides.
Li, Huan; Noh, Jong W; Chen, Yu; Li, Mo
2013-05-20
We demonstrate gradient optical forces in metal-dielectric hybrid plasmonic waveguides (HPWG) for the first time. The magnitude of optical force is quantified through excitation of the nanomechanical vibration of the suspended waveguides. Integrated Mach-Zehnder interferometry is utilized to transduce the mechanical motion and characterize the propagation loss of the HPWG. Compared with theory, the experimental results have confirmed the optical force enhancement, but also suggested a significantly higher optical loss in HPWG. The excessive loss is attributed to metal surface roughness and other non-idealities in the device fabrication process. PMID:23736405
Hybrid two-chain simulation and integral equation theory : application to polyethylene liquids.
Huimin Li, David T. Wu (Colorado School of Mines Golden, CO.); Curro, John G.; McCoy, John Dwane (New Mexico Institute of Mining & Technology Socorro, NM.)
2006-02-01
We present results from a hybrid simulation and integral equation approach to the calculation of polymer melt properties. The simulation consists of explicit Monte Carlo (MC) sampling of two polymer molecules, where the effect of the surrounding chains is accounted for by an HNC solvation potential. The solvation potential is determined from the Polymer Reference Interaction Site Model (PRISM) as a functional of the pair correlation function from simulation. This hybrid two-chain MC-PRISM approach was carried out on liquids of polyethylene chains of 24 and 66 CH{sub 2} units. The results are compared with MD simulation and self-consistent PRISM-PY theory under the same conditions, revealing that the two-chain calculation is close to MD, and able to overcome the defects of the PRISM-PY closure and predict more accurate structures of the liquid at both short and long range. The direct correlation function, for instance, has a tail at longer range which is consistent with MD simulation and avoids the short-range assumptions in PRISM-PY theory. As a result, the self-consistent two-chain MC-PRISM calculation predicts an isothermal compressibility closer to the MD results.
NASA Astrophysics Data System (ADS)
Estrin, Darío. A.; Kohanoff, Jorge; Laria, Daniel H.; Weht, Ruben O.
1997-12-01
Monte Carlo simulations using a hybrid quantum and classical mechanical potential were performed for crystal and amorphous-like HCl(H 2O) n clusters ( n?24). The subsystem composed by HCl and one water molecule was treated within density functional theory and a classical force field was used for the rest of the system. Simulations performed at 200 K suggest that the energetic feasibility of HCl dissociation strongly depends on its initial placement within the cluster. An important degree of ionization occurs only if HCl is incorporated into the surface. We observe that local melting does not play a crucial role in the ionization process.
First Results From GLAST-LAT Integrated Towers Cosmic Ray Data Taking And Monte Carlo Comparison
Brigida, M.; Caliandro, A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giordano, F.; Giglietto, N.; Loparco, F.; Marangelli, B.; Mazziotta, M.N.; Mirizzi, N.; Raino, S.; Spinelli, P.; /Bari U. /INFN, Bari
2007-02-15
GLAST Large Area Telescope (LAT) is a gamma ray telescope instrumented with silicon-strip detector planes and sheets of converter, followed by a calorimeter (CAL) and surrounded by an anticoincidence system (ACD). This instrument is sensitive to gamma rays in the energy range between 20 MeV and 300 GeV. At present, the first towers have been integrated and pre-launch data taking with cosmic ray muons is being performed. The results from the data analysis carried out during LAT integration will be discussed and a comparison with the predictions from the Monte Carlo simulation will be shown.
Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms.
Markos, Christos; Kubat, Irnis; Bang, Ole
2014-01-01
The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass nanofilms at the inner surface of the air-channels of a poly-methyl-methacrylate (PMMA) PCF. The integrated high refractive index glass films introduce distinct antiresonant transmission bands in the 480-900 nm wavelength region. We demonstrate that the ultra-high Kerr nonlinearity of the chalcogenide glass makes the polymer PCF nonlinear and provides a possibility to shift the transmission band edges as much as 17 nm by changing the intensity. The proposed fabrication technique constitutes a new highway towards all-fiber nonlinear tunable devices based on polymer PCFs, which at the moment is not possible with any other fabrication method. PMID:25317501
Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms
NASA Astrophysics Data System (ADS)
Markos, Christos; Kubat, Irnis; Bang, Ole
2014-08-01
The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass nanofilms at the inner surface of the air-channels of a poly-methyl-methacrylate (PMMA) PCF. The integrated high refractive index glass films introduce distinct antiresonant transmission bands in the 480-900 nm wavelength region. We demonstrate that the ultra-high Kerr nonlinearity of the chalcogenide glass makes the polymer PCF nonlinear and provides a possibility to shift the transmission band edges as much as 17 nm by changing the intensity. The proposed fabrication technique constitutes a new highway towards all-fiber nonlinear tunable devices based on polymer PCFs, which at the moment is not possible with any other fabrication method.
Hybrid Silicon Photonic Integration using Quantum Well Intermixing
NASA Astrophysics Data System (ADS)
Jain, Siddharth R.
With the push for faster data transfer across all domains of telecommunication, optical interconnects are transitioning into shorter range applications such as in data centers and personal computing. Silicon photonics, with its economic advantages of leveraging well-established silicon manufacturing facilities, is considered the most promising approach to further scale down the cost and size of optical interconnects for chip-to-chip communication. Intrinsic properties of silicon however limit its ability to generate and modulate light, both of which are key to realizing on-chip optical data transfer. The hybrid silicon approach directly addresses this problem by using molecularly bonded III-V epitaxial layers on silicon for optical gain and absorption. This technology includes direct transfer of III-V wafer to a pre-patterned silicon-on-insulator wafer. Several discrete devices for light generation, modulation, amplification and detection have already been demonstrated on this platform. As in the case of electronics, multiple photonic elements can be integrated on a single chip to improve performance and functionality. However, scalable photonic integration requires the ability to control the bandgap for individual devices along with design changes to simplify fabrication. In the research presented here, quantum well intermixing is used as a technique to define multiple bandgaps for integration on the hybrid silicon platform. Implantation enhanced disordering is used to generate four bandgaps spread over 120+ nm. By combining these selectively intermixed III-V layers with pre-defined gratings and waveguides on silicon, we fabricate distributed feedback, distributed Bragg reflector, Fabry-Perot and mode-locked lasers along with photodetectors, electro-absorption modulators and other test structures, all on a single chip. We demonstrate a broadband laser source with continuous-wave operational lasers over a 200 nm bandwidth. Some of these lasers are integrated with modulators with a 3-dB bandwidth above 25 GHz, thus demonstrating coarse wavelength division multiplexing transmitter on silicon.
Hybrid integrated optic modules for real-time signal processing
NASA Technical Reports Server (NTRS)
Tsai, C. S.
1984-01-01
The most recent progress on four relatively new hybrid integrated optic device modules in LiNbO3 waveguides and one in YIG/GGG waveguide that are currently being studied are discussed. The five hybrid modules include a time-integrating acoustooptic correlator, a channel waveguide acoustooptic frequency shifter/modulator, an electrooptic channel waveguide total internal reflection moculator/switch, an electrooptic analog-to-digital converter using a Fabry-Perot modulator array, and a noncollinear magnetooptic modulator using magnetostatic surface waves. All of these devices possess the desirable characteristics of very large bandwidth (GHz or higher), very small substrate size along the optical path (typically 1.5 cm or less), single-mode optical propagation, and low drive power requirement. The devices utilize either acoustooptic, electrooptic or magnetooptic effects in planar or channel waveguides and, therefore, act as efficient interface devices between a light wave and temporal signals. Major areas of application lie in wideband multichannel optical real-time signal processing and communications. Some of the specific applications include spectral analysis and correlation of radio frequency (RF) signals, fiber-optic sensing, optical computing and multiport switching/routing, and analog-to-digital conversion of wide RF signals.
2001-01-1334 Integrated, Feed-Forward Hybrid Electric Vehicle
Peng, Huei
1 2001-01-1334 Integrated, Feed-Forward Hybrid Electric Vehicle Simulation in SIMULINK and its Use of Automotive Engineers, Inc. ABSTRACT A hybrid electric vehicle simulation tool (HE-VESIM) has been developed global crude oil supplies stimulate research aimed at new, fuel-efficient vehicle technologies. Hybrid-electric
Better HMC integrators for dynamical simulations
M.A. Clark, Balint Joo, A.D. Kennedy, P.J. Silva
2010-06-01
We show how to improve the molecular dynamics step of Hybrid Monte Carlo, both by tuning the integrator using Poisson brackets measurements and by the use of force gradient integrators. We present results for moderate lattice sizes.
NASA Astrophysics Data System (ADS)
Eylenceo?lu, E.; Rafatov, I.; Kudryavtsev, A. A.
2015-01-01
Two-dimensional hybrid Monte Carlo-fluid numerical code is developed and applied to model the dc glow discharge. The model is based on the separation of electrons into two parts: the low energetic (slow) and high energetic (fast) electron groups. Ions and slow electrons are described within the fluid model using the drift-diffusion approximation for particle fluxes. Fast electrons, represented by suitable number of super particles emitted from the cathode, are responsible for ionization processes in the discharge volume, which are simulated by the Monte Carlo collision method. Electrostatic field is obtained from the solution of Poisson equation. The test calculations were carried out for an argon plasma. Main properties of the glow discharge are considered. Current-voltage curves, electric field reversal phenomenon, and the vortex current formation are developed and discussed. The results are compared to those obtained from the simple and extended fluid models. Contrary to reports in the literature, the analysis does not reveal significant advantages of existing hybrid methods over the extended fluid model.
S. Yalcin; O. Gurler; G. Kaynak; O. Gundogdu
2007-01-01
This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are
S. M. Mesli; M. Habchi; M. Kotbi; H. Xu
2013-03-25
The choice of appropriate interaction models is among the major disadvantages of conventional methods such as molecular dynamics and Monte Carlo simulations. On the other hand, the so-called reverse Monte Carlo (RMC) method, based on experimental data, can be applied without any interatomic and/or intermolecular interactions. The RMC results are accompanied by artificial satellite peaks. To remedy this problem, we use an extension of the RMC algorithm, which introduces an energy penalty term into the acceptance criteria. This method is referred to as the hybrid reverse Monte Carlo (HRMC) method. The idea of this paper is to test the validity of a combined potential model of coulomb and Lennard-Jones in a fluoride glass system BaMnMF_{7} (M=Fe,V) using HRMC method. The results show a good agreement between experimental and calculated characteristics, as well as a meaningful improvement in partial pair distribution functions. We suggest that this model should be used in calculating the structural properties and in describing the average correlations between components of fluoride glass or a similar system. We also suggest that HRMC could be useful as a tool for testing the interaction potential models, as well as for conventional applications.
Modeling Integrated Cellular Machinery Using Hybrid Petri-Boolean Networks
Berestovsky, Natalie; Zhou, Wanding; Nagrath, Deepak; Nakhleh, Luay
2013-01-01
The behavior and phenotypic changes of cells are governed by a cellular circuitry that represents a set of biochemical reactions. Based on biological functions, this circuitry is divided into three types of networks, each encoding for a major biological process: signal transduction, transcription regulation, and metabolism. This division has generally enabled taming computational complexity dealing with the entire system, allowed for using modeling techniques that are specific to each of the components, and achieved separation of the different time scales at which reactions in each of the three networks occur. Nonetheless, with this division comes loss of information and power needed to elucidate certain cellular phenomena. Within the cell, these three types of networks work in tandem, and each produces signals and/or substances that are used by the others to process information and operate normally. Therefore, computational techniques for modeling integrated cellular machinery are needed. In this work, we propose an integrated hybrid model (IHM) that combines Petri nets and Boolean networks to model integrated cellular networks. Coupled with a stochastic simulation mechanism, the model simulates the dynamics of the integrated network, and can be perturbed to generate testable hypotheses. Our model is qualitative and is mostly built upon knowledge from the literature and requires fine-tuning of very few parameters. We validated our model on two systems: the transcriptional regulation of glucose metabolism in human cells, and cellular osmoregulation in S. cerevisiae. The model produced results that are in very good agreement with experimental data, and produces valid hypotheses. The abstract nature of our model and the ease of its construction makes it a very good candidate for modeling integrated networks from qualitative data. The results it produces can guide the practitioner to zoom into components and interconnections and investigate them using such more detailed mathematical models. PMID:24244124
Hybrid Integrated Silicon Microfluidic Platform for Fluorescence Based Biodetection
Chandrasekaran, Arvind; Acharya, Ashwin; You, Jian Liang; Soo, Kim Young; Packirisamy, Muthukumaran; Stiharu, Ion; Darveau, Andre
2007-01-01
The desideratum to develop a fully integrated Lab-on-a-chip device capable of rapid specimen detection for high throughput in-situ biomedical diagnoses and Point-of-Care testing applications has called for the integration of some of the novel technologies such as the microfluidics, microphotonics, immunoproteomics and Micro Electro Mechanical Systems (MEMS). In the present work, a silicon based microfluidic device has been developed for carrying out fluorescence based immunoassay. By hybrid attachment of the microfluidic device with a Spectrometer-on-chip, the feasibility of synthesizing an integrated Lab-on-a-chip type device for fluorescence based biosensing has been demonstrated. Biodetection using the microfluidic device has been carried out using antigen sheep IgG and Alexafluor-647 tagged antibody particles and the experimental results prove that silicon is a compatible material for the present application given the various advantages it offers such as cost-effectiveness, ease of bulk microfabrication, superior surface affinity to biomolecules, ease of disposability of the device etc., and is thus suitable for fabricating Lab-on-a-chip type devices.
Hybrid Clustering by Integrating Text and Citation based Graphs in Journal Database Analysis
Hybrid Clustering by Integrating Text and Citation based Graphs in Journal Database Analysis Xinhai to large scale journal database and immediate clustering task. On the hand, many graph partition algorithms.Glanzel@econ.kuleuven.ac.be Abstract We propose a hybrid clustering strategy by integrating heterogeneous information sources as graphs
Hybrid silicon integration R. Jones H. D. Park A. W. Fang J. E. Bowers O. Cohen
Bowers, John
Hybrid silicon integration R. Jones Ã? H. D. Park Ã? A. W. Fang Ã? J. E. Bowers Ã? O. Cohen Ã? O. Raday+Business Media, LLC 2007 Abstract An overview is presented of the hybrid AlGa- InAs-silicon platform that enables wafer level integration of III-V optoelectronic devices with silicon photonic devices based on silicon
Sharma, Diksha; Badal, Andreu; Badano, Aldo
2012-04-21
The computational modeling of medical imaging systems often requires obtaining a large number of simulated images with low statistical uncertainty which translates into prohibitive computing times. We describe a novel hybrid approach for Monte Carlo simulations that maximizes utilization of CPUs and GPUs in modern workstations. We apply the method to the modeling of indirect x-ray detectors using a new and improved version of the code MANTIS, an open source software tool used for the Monte Carlo simulations of indirect x-ray imagers. We first describe a GPU implementation of the physics and geometry models in fastDETECT2 (the optical transport model) and a serial CPU version of the same code. We discuss its new features like on-the-fly column geometry and columnar crosstalk in relation to the MANTIS code, and point out areas where our model provides more flexibility for the modeling of realistic columnar structures in large area detectors. Second, we modify PENELOPE (the open source software package that handles the x-ray and electron transport in MANTIS) to allow direct output of location and energy deposited during x-ray and electron interactions occurring within the scintillator. This information is then handled by optical transport routines in fastDETECT2. A load balancer dynamically allocates optical transport showers to the GPU and CPU computing cores. Our hybridMANTIS approach achieves a significant speed-up factor of 627 when compared to MANTIS and of 35 when compared to the same code running only in a CPU instead of a GPU. Using hybridMANTIS, we successfully hide hours of optical transport time by running it in parallel with the x-ray and electron transport, thus shifting the computational bottleneck from optical tox-ray transport. The new code requires much less memory than MANTIS and, asa result, allows us to efficiently simulate large area detectors. PMID:22469917
Integrated power divider/combiner at hybrid orthogonal junctions
NASA Astrophysics Data System (ADS)
El Sherif, Mohamed H.; Ahmed, Osman S.; Bakr, Mohamed H.
2014-03-01
We propose an integrated power divider/combiner at the interface between silicon nanowire and plasmonic slot waveguide (PSW). The proposed configuration facilitates light access and manipulation in planar nano-plasmonic circuits. The light is incident from a standard silicon nanowire to be accessed by a nano-plasmonic circuit providing subwavelength confinement. The structure overcomes the losses associated with long distance light propagation in nanoplasmonic splitters as coupling and splitting are performed at the same interface with minimal losses. Two PSWs placed orthogonally to the silicon nanowire forming hybrid junctions are exploited for the power dividing/combining functionality. The power splitter has been analyzed using the finite difference time domain (FDTD) numerical method. The ultra-compact proposed device provides wide-band power splitting functionality. A splitting of 34.7%, over most of the wavelength spectrum from 0.8 ?m - 2.5 ?m, is demonstrated.
Golden Ratio Versus Pi as Random Sequence Sources for Monte Carlo Integration
NASA Technical Reports Server (NTRS)
Sen, S. K.; Agarwal, Ravi P.; Shaykhian, Gholam Ali
2007-01-01
We discuss here the relative merits of these numbers as possible random sequence sources. The quality of these sequences is not judged directly based on the outcome of all known tests for the randomness of a sequence. Instead, it is determined implicitly by the accuracy of the Monte Carlo integration in a statistical sense. Since our main motive of using a random sequence is to solve real world problems, it is more desirable if we compare the quality of the sequences based on their performances for these problems in terms of quality/accuracy of the output. We also compare these sources against those generated by a popular pseudo-random generator, viz., the Matlab rand and the quasi-random generator ha/ton both in terms of error and time complexity. Our study demonstrates that consecutive blocks of digits of each of these numbers produce a good random sequence source. It is observed that randomly chosen blocks of digits do not have any remarkable advantage over consecutive blocks for the accuracy of the Monte Carlo integration. Also, it reveals that pi is a better source of a random sequence than theta when the accuracy of the integration is concerned.
Andújar, C; Arribas, P; Ruiz, C; Serrano, J; Gómez-Zurita, J
2014-09-01
In species differentiation, characters may not diverge synchronously, and there are also processes that shuffle character states in lineages descendant from a common ancestor. Species are thus expected to show some degree of incongruence among characters; therefore, taxonomic delimitation can benefit from integrative approaches and objective strategies that account for character conflict. We illustrate the potential of exploiting conflict for species delimitation in a study case of ground beetles of the subgenus Carabus (Mesocarabus), where traditional taxonomy does not accurately delimit species. The molecular phylogenies of four mitochondrial and three nuclear genes, cladistic analysis of the aedeagus, ecological niche divergence and morphometry of pronotal shape in more than 500 specimens of Mesocarabus show that these characters are not fully congruent. For these data, a three-step operational strategy is proposed for species delimitation by (i) delineating candidate species based on the integration of incongruence among conclusive lines of evidence, (ii) corroborating candidate species with inconclusive lines of evidence and (iii) refining a final species proposal based on an integrated characterization of candidate species based on the evolutionary analysis of incongruence. This procedure provided a general understanding of the reticulate process of hybridization and introgression acting on Mesocarabus and generated the hypothesis of seven Mesocarabus species, including two putative hybrid lineages. Our work emphasizes the importance of incorporating critical analyses of character and phylogenetic conflict to infer both the evolutionary history and species boundaries through an integrative taxonomic approach. PMID:24828576
Hybrid automated reliability predictor integrated work station (HiREL)
NASA Technical Reports Server (NTRS)
Bavuso, Salvatore J.
1991-01-01
The Hybrid Automated Reliability Predictor (HARP) integrated reliability (HiREL) workstation tool system marks another step toward the goal of producing a totally integrated computer aided design (CAD) workstation design capability. Since a reliability engineer must generally graphically represent a reliability model before he can solve it, the use of a graphical input description language increases productivity and decreases the incidence of error. The captured image displayed on a cathode ray tube (CRT) screen serves as a documented copy of the model and provides the data for automatic input to the HARP reliability model solver. The introduction of dependency gates to a fault tree notation allows the modeling of very large fault tolerant system models using a concise and visually recognizable and familiar graphical language. In addition to aiding in the validation of the reliability model, the concise graphical representation presents company management, regulatory agencies, and company customers a means of expressing a complex model that is readily understandable. The graphical postprocessor computer program HARPO (HARP Output) makes it possible for reliability engineers to quickly analyze huge amounts of reliability/availability data to observe trends due to exploratory design changes.
El Bitar, Z; Pino, F; Candela, C; Ros, D; Pavía, J; Rannou, F R; Ruibal, A; Aguiar, P
2014-11-21
It is well-known that in pinhole SPECT (single-photon-emission computed tomography), iterative reconstruction methods including accurate estimations of the system response matrix can lead to submillimeter spatial resolution. There are two different methods for obtaining the system response matrix: those that model the system analytically using an approach including an experimental characterization of the detector response, and those that make use of Monte Carlo simulations. Methods based on analytical approaches are faster and handle the statistical noise better than those based on Monte Carlo simulations, but they require tedious experimental measurements of the detector response. One suggested approach for avoiding an experimental characterization, circumventing the problem of statistical noise introduced by Monte Carlo simulations, is to perform an analytical computation of the system response matrix combined with a Monte Carlo characterization of the detector response. Our findings showed that this approach can achieve high spatial resolution similar to that obtained when the system response matrix computation includes an experimental characterization. Furthermore, we have shown that using simulated detector responses has the advantage of yielding a precise estimate of the shift between the point of entry of the photon beam into the detector and the point of interaction inside the detector. Considering this, it was possible to slightly improve the spatial resolution in the edge of the field of view. PMID:25415206
Data assimilation using a GPU accelerated path integral Monte Carlo approach
NASA Astrophysics Data System (ADS)
Quinn, John C.; Abarbanel, Henry D. I.
2011-09-01
The answers to data assimilation questions can be expressed as path integrals over all possible state and parameter histories. We show how these path integrals can be evaluated numerically using a Markov Chain Monte Carlo method designed to run in parallel on a graphics processing unit (GPU). We demonstrate the application of the method to an example with a transmembrane voltage time series of a simulated neuron as an input, and using a Hodgkin-Huxley neuron model. By taking advantage of GPU computing, we gain a parallel speedup factor of up to about 300, compared to an equivalent serial computation on a CPU, with performance increasing as the length of the observation time used for data assimilation increases.
State and parameter estimation using Monte Carlo evaluation of path integrals
John C. Quinn; Henry D. I. Abarbanel
2009-12-08
Transferring information from observations of a dynamical system to estimate the fixed parameters and unobserved states of a system model can be formulated as the evaluation of a discrete time path integral in model state space. The observations serve as a guiding potential working with the dynamical rules of the model to direct system orbits in state space. The path integral representation permits direct numerical evaluation of the conditional mean path through the state space as well as conditional moments about this mean. Using a Monte Carlo method for selecting paths through state space we show how these moments can be evaluated and demonstrate in an interesting model system the explicit influence of the role of transfer of information from the observations. We address the question of how many observations are required to estimate the unobserved state variables, and we examine the assumptions of Gaussianity of the underlying conditional probability.
Monte Carlo Simulations of Globular Cluster Evolution. IV. Direct Integration of Strong Interactions
John M. Fregeau; Frederic A. Rasio
2006-12-06
We study the dynamical evolution of globular clusters containing populations of primordial binaries, using our newly updated Monte Carlo cluster evolution code with the inclusion of direct integration of binary scattering interactions. We describe the modifications we have made to the code, as well as improvements we have made to the core Monte Carlo method. We present several test calculations to verify the validity of the new code, and perform many comparisons with previous analytical and numerical work in the literature. We simulate the evolution of a large grid of models, with a wide range of initial cluster profiles, and with binary fractions ranging from 0 to 1, and compare with observations of Galactic globular clusters. We find that our code yields very good agreement with direct N-body simulations of clusters with primordial binaries, but yields some results that differ significantly from other approximate methods. Notably, the direct integration of binary interactions reduces their energy generation rate relative to the simple recipes used in Paper III, and yields smaller core radii. Our results for the structural parameters of clusters during the binary-burning phase are now in the tail of the range of parameters for observed clusters, implying that either clusters are born significantly more or less centrally concentrated than has been previously considered, or that there are additional physical processes beyond two-body relaxation and binary interactions that affect the structural characteristics of clusters.
Comparison of symbolic and numerical integration methods for an assumed-stress hybrid shell element
NASA Technical Reports Server (NTRS)
Rengarajan, Govind; Knight, Norman F., Jr.; Aminpour, Mohammad A.
1993-01-01
Hybrid shell elements have long been regarded with reserve by the commercial finite element developers despite the high degree of reliability and accuracy associated with such formulations. The fundamental reason is the inherent higher computational cost of the hybrid approach as compared to the displacement-based formulations. However, a noteworthy factor in favor of hybrid elements is that numerical integration to generate element matrices can be entirely avoided by the use of symbolic integration. In this paper, the use of the symbolic computational approach is presented for an assumed-stress hybrid shell element with drilling degrees of freedom and the significant time savings achieved is demonstrated through an example.
Time-dependent Integrated Modeling of AT, Hybrid, and ELMy H-mode Plasmas in ITER
Budny, Robert
Integrated modeling needed for the nonlinearities and strong cou- pling of plasma conditions, heating considered AT plasma: low current, fully non-inductive Hybrid plasma: q(0) 1.0-2.0 Sawtoothing ELMy H LABORATORY PPPL 7 #12;Heating powers and plasma currents in the Hybrid plasma P ICRH P NNBI P fast ion P P
Platform technologies for hybrid optoelectronic integration and packaging
NASA Astrophysics Data System (ADS)
Datta, Madhumita
In order to bring fiber-optics closer to individual home and business services, the optical network components have to be inexpensive and reliable. Integration and packaging of optoelectronic devices holds the key to high-volume low-cost component manufacturing. The goal of this dissertation is to propose, study, and demonstrate various ways to integrate optoelectronic devices on a packaging platform to implement cost-effective, functional optical modules. Two types of hybrid integration techniques have been proposed: flip-chip solder bump bonding for high-density two-dimensional array packaging of surface-emitting devices, and solder preform bonding for fiber-coupled edge-emitting semiconductor devices. For flip-chip solder bump bonding, we developed a simple, inexpensive remetallization process called "electroless plating", which converts the aluminum bond pads of foundry-made complementary metal oxide semiconductor (CMOS) chips into solder-bondable and wire-bondable gold surfaces. We have applied for a patent on this remetallization technique. For fiber-pigtailed edge-emitting laser modules, we have studied the coupling characteristics of different types of lensed single-mode fibers including semispherically lensed fiber, cylindrically lensed fiber and conically lensed fiber. We have experimentally demonstrated 66% coupling efficiency with semispherically lensed fiber and 50% efficiency with conically lensed fibers. We have proposed and designed a packaging platform on which lensed fibers can be actively aligned to a laser and solder-attached reliably to the platform so that the alignment is retained. We have designed thin-film nichrome heaters on fused quartz platforms as local heat source to facilitate on-board solder alignment and attachment of fiber. The thermal performance of the heaters was simulated using finite element analysis tool ANSYS prior to fabrication. Using the heater's reworkability advantage, we have estimated the shift of the fiber due to solder shrinkage and introduced a pre-correction in the alignment process to restore optimum coupling efficiency close to 50% with conically lensed fibers. We have applied for a patent on this unique active alignment method through the University of Maryland's Technology Commercialization Office. Although we have mostly concentrated on active alignment platforms, we have proposed the idea of combining the passive alignment advantages of silicon optical benches to the on-board heater-assisted active alignment technique. This passive-active alignment process has the potential of cost-effective array packaging of edge-emitting devices.
Integrating Shape and Texture in Deformable Models: from Hybrid Methods to Metamorphs
Huang, Xiaolei
Integrating Shape and Texture in Deformable Models: from Hybrid Methods to Metamorphs Dimitris models, which we term "Metamorphs". The novel formulation of the Metamorph models tightly couples shape and region information in a variational framework. Keywords Metamorphs, deformable models, implicit
Accelerating execution of the integrated TIGER series Monte Carlo radiation transport codes
Smith, L.M.; Hochstedler, R.D. [Univ of Tennessee Space Inst., Tullahoma, TN (United States). Dept. of Electrical Engineering] [Univ of Tennessee Space Inst., Tullahoma, TN (United States). Dept. of Electrical Engineering
1997-02-01
Execution of the integrated TIGER series (ITS) of coupled electron/photon Monte Carlo radiation transport codes has been accelerated by modifying the FORTRAN source code for more efficient computation. Each member code of ITS was benchmarked and profiled with a specific test case that directed the acceleration effort toward the most computationally intensive subroutines. Techniques for accelerating these subroutines included replacing linear search algorithms with binary versions, replacing the pseudo-random number generator, reducing program memory allocation, and proofing the input files for geometrical redundancies. All techniques produced identical or statistically similar results to the original code. Final benchmark timing of the accelerated code resulted in speed-up factors of 2.00 for TIGER (the one-dimensional slab geometry code), 1.74 for CYLTRAN (the two-dimensional cylindrical geometry code), and 1.90 for ACCEPT (the arbitrary three-dimensional geometry code).
Monte Carlo Depletion Analysis of a PWR Integral Fuel Burnable Absorber by MCNAP
NASA Astrophysics Data System (ADS)
Shim, H. J.; Jang, C. S.; Kim, C. H.
The MCNAP is a personal computer-based continuous energy Monte Carlo (MC) neutronics analysis program written on C++ language. For the purpose of examining its qualification, a comparison of the depletion analysis of three integral burnable fuel assemblies of the pressurized water reactor (PWR) by the MCNAP and deterministic fuel assembly (FA) design vendor codes is presented. It is demonstrated that the continuous energy MC calculation by the MCNAP can provide a very accurate neutronics analysis method for the burnable absorber FA's. It is also demonstrated that the parallel MC computation by adoption of multiple PC's enables one to complete the lifetime depletion analysis of the FA's within the order of hours instead of order of days otherwise.
Monte-Carlo experiments on star-cluster induced integrated-galaxy IMF variations
Carsten Weidner; Pavel Kroupa
2004-09-30
As most if not all stars are born in stellar clusters the shape of the mass function of the field stars is not only determined by the initial mass function of stars (IMF) but also by the cluster mass function (CMF). In order to quantify this Monte-Carlo simulations were carried out by taking cluster masses randomly from a CMF and then populating these clusters with stars randomly taken from an IMF. Two cases were studied. Firstly the star masses were added randomly until the cluster mass was reached. Secondly a number of stars, given by the cluster mass divided by an estimate of the mean stellar mass and sorted by mass, were added until the desired cluster mass was reached. Both experiments verified the analytical results of Kroupa & Weidner (2003) that the resulting integrated stellar initial mass function is a folding of the IMF with the CMF and therefore steeper than the input IMF above 1 Msol.
Torsional path integral Monte Carlo method for the quantum simulation of large molecules
NASA Astrophysics Data System (ADS)
Miller, Thomas F.; Clary, David C.
2002-05-01
A molecular application is introduced for calculating quantum statistical mechanical expectation values of large molecules at nonzero temperatures. The Torsional Path Integral Monte Carlo (TPIMC) technique applies an uncoupled winding number formalism to the torsional degrees of freedom in molecular systems. The internal energy of the molecules ethane, n-butane, n-octane, and enkephalin are calculated at standard temperature using the TPIMC technique and compared to the expectation values obtained using the harmonic oscillator approximation and a variational technique. All studied molecules exhibited significant quantum mechanical contributions to their internal energy expectation values according to the TPIMC technique. The harmonic oscillator approximation approach to calculating the internal energy performs well for the molecules presented in this study but is limited by its neglect of both anharmonicity effects and the potential coupling of intramolecular torsions.
Kinetic energy of solid and liquid para-hydrogen: a path integral Monte Carlo simulation
NASA Astrophysics Data System (ADS)
Zoppi, Marco; Neumann, Martin
1992-06-01
The translational (center of mass) kinetic energy of solid and liquid para-hydrogen have been recently measured by means of Deep Inelastic Neutron Scattering. We have evaluated the same quantity, in similar thermodynamic conditions, by means of Path Integral Monte Carlo computer simulation, modelling the system as composed of a set of spherical molecules interacting through a pairwise additive Lennard-Jones potential. In spite of the crude approximations on the interaction potential, the agreement is excellent. The pressure was also computed by means of the same simulations. This quantity, compared with the equation of state for solid para-hydrogen given by Driessen and Silvera, gives an agreement of a lesser quality and a negative value for the liquid state. We attribute this discrepancy to the limitations of the Lennard-Jones potential.
Fermionic path-integral Monte Carlo results for the uniform electron gas at finite temperature
NASA Astrophysics Data System (ADS)
Filinov, V. S.; Fortov, V. E.; Bonitz, M.; Moldabekov, Zh.
2015-03-01
The uniform electron gas (UEG) at finite temperature has recently attracted substantial interest due to the experimental progress in the field of warm dense matter. To explain the experimental data, accurate theoretical models for high-density plasmas are needed that depend crucially on the quality of the thermodynamic properties of the quantum degenerate nonideal electrons and of the treatment of their interaction with the positive background. Recent fixed-node path-integral Monte Carlo (RPIMC) data are believed to be the most accurate for the UEG at finite temperature, but they become questionable at high degeneracy when the Brueckner parameter rs=a /aB —the ratio of the mean interparticle distance to the Bohr radius—approaches 1. The validity range of these simulations and their predictive capabilities for the UEG are presently unknown. This is due to the unknown quality of the used fixed nodes and of the finite-size scaling from N =33 simulated particles (per spin projection) to the macroscopic limit. To analyze these questions, we present alternative direct fermionic path integral Monte Carlo (DPIMC) simulations that are independent from RPIMC. Our simulations take into account quantum effects not only in the electron system but also in their interaction with the uniform positive background. Also, we use substantially larger particle numbers (up to three times more) and perform an extrapolation to the macroscopic limit. We observe very good agreement with RPIMC, for the polarized electron gas, up to moderate densities around rs=4 , and larger deviations for the unpolarized case, for low temperatures. For higher densities (high electron degeneracy), rs?1.5 , both RPIMC and DPIMC are problematic due to the increased fermion sign problem.
Hybrid-integrated coherent receiver using silica-based planar lightwave circuit technology
NASA Astrophysics Data System (ADS)
Kim, Jong-Hoi; Choe, Joong-Seon; Choi, Kwang-Seong; Youn, Chun-Ju; Kim, Duk-Jun; Jang, Sun-Hyok; Kwon, Yong-Hwan; Nam, Eun-Soo
2011-12-01
A hybrid-integrated coherent receiver module has been achieved using flip-chip bonding technology, consisting of a silica-based 90°-hybrid planar lightwave circuit (PLC) platform, a spot-size converter integrated waveguide photodiode (SSC-WG-PD), and a dual-channel transimpedance amplifier (TIA). The receiver module shows error-free operation up to 40Gb/s and OSNR sensitivity of 11.5 dB for BER = 10-3 at 25 Gb/s.
Two-Dimensional Integrated Circuits for Hybrid Solid-State Pixel Detectors
T. O. Tumer; V. B. Cajipe; M. Clajus; Hayakawa S
2006-01-01
We have developed custom two-dimensional (2-D) mixed signal readout integrated circuits (ICs) for advanced position sensitive hybrid solid-state radiation detectors. The 2-D readout ICs are an integral part of hybrid semiconductor pixel detectors developed for X-ray, gamma-ray and charged particle imaging. Different detector applications require custom IC, which is typically designed for a specific 2-D detector array. Therefore, it is
Hybrid integrated bi-directional module using polymeric WDM filter based on multimode interference
Jung Woon Lim; Sung Hwan Hwang; Woo-Jin Lee; Tae Ho Lee; Myung Yong Jeong; Boo-Gyoun Kim; Byung Sup Rho
2009-01-01
We have presented a polymer wavelength division multiplexing (WDM) filter based on multimode interference and developed a hybrid integrated optical module for 1.31\\/1.55-mum bidirectional operation. The active devices were integrated on a silicon optical bench platform by flip-chip bonding technique. The polymer WDM filter chip using polymethylmethacrylate (PMMA) was fabricated by the hot embossing technique. This hybrid module exhibited a
Radiation Transport for Explosive Outflows: A Multigroup Hybrid Monte Carlo Method
NASA Astrophysics Data System (ADS)
Wollaeger, Ryan T.; van Rossum, Daniel R.; Graziani, Carlo; Couch, Sean M.; Jordan, George C., IV; Lamb, Donald Q.; Moses, Gregory A.
2013-12-01
We explore Implicit Monte Carlo (IMC) and discrete diffusion Monte Carlo (DDMC) for radiation transport in high-velocity outflows with structured opacity. The IMC method is a stochastic computational technique for nonlinear radiation transport. IMC is partially implicit in time and may suffer in efficiency when tracking MC particles through optically thick materials. DDMC accelerates IMC in diffusive domains. Abdikamalov extended IMC and DDMC to multigroup, velocity-dependent transport with the intent of modeling neutrino dynamics in core-collapse supernovae. Densmore has also formulated a multifrequency extension to the originally gray DDMC method. We rigorously formulate IMC and DDMC over a high-velocity Lagrangian grid for possible application to photon transport in the post-explosion phase of Type Ia supernovae. This formulation includes an analysis that yields an additional factor in the standard IMC-to-DDMC spatial interface condition. To our knowledge the new boundary condition is distinct from others presented in prior DDMC literature. The method is suitable for a variety of opacity distributions and may be applied to semi-relativistic radiation transport in simple fluids and geometries. Additionally, we test the code, called SuperNu, using an analytic solution having static material, as well as with a manufactured solution for moving material with structured opacities. Finally, we demonstrate with a simple source and 10 group logarithmic wavelength grid that IMC-DDMC performs better than pure IMC in terms of accuracy and speed when there are large disparities between the magnitudes of opacities in adjacent groups. We also present and test our implementation of the new boundary condition.
Extension of the Integrated Tiger Series (ITS) of electron-photon Monte Carlo codes to 100 GeV
Miller, S.G.
1988-08-01
Version 2.1 of the Integrated Tiger Series (ITS) of electron-photon Monte Carlo codes was modified to extend their ability to model interactions up to 100 GeV. Benchmarks against experimental results conducted at 10 and 15 GeV confirm the accuracy of the extended codes. 12 refs., 2 figs., 2 tabs.
Streamline Integration using MPI-Hybrid Parallelism on a Large Multi-Core Architecture
Camp, David; Garth, Christoph; Childs, Hank; Pugmire, Dave; Joy, Kenneth I.
2010-11-01
Streamline computation in a very large vector field data set represents a significant challenge due to the non-local and datadependentnature of streamline integration. In this paper, we conduct a study of the performance characteristics of hybrid parallel programmingand execution as applied to streamline integration on a large, multicore platform. With multi-core processors now prevalent in clustersand supercomputers, there is a need to understand the impact of these hybrid systems in order to make the best implementation choice.We use two MPI-based distribution approaches based on established parallelization paradigms, parallelize-over-seeds and parallelize-overblocks,and present a novel MPI-hybrid algorithm for each approach to compute streamlines. Our findings indicate that the work sharing betweencores in the proposed MPI-hybrid parallel implementation results in much improved performance and consumes less communication andI/O bandwidth than a traditional, non-hybrid distributed implementation.
M. Boettcher; R. Saxena; A. W. Crider
2001-02-16
We suggest a simple fitting formula to represent Comptonized X- and gamma-ray spectra from a hot ($kT_e \\gtrsim 10$ keV), Thomson thick ($\\tau_T \\gtrsim 5$) hybrid thermal/nonthermal plasma in spherical geometry with homogeneous soft-photon injection throughout the Comptonizing region. We have used this formula to fit a large data base of Monte-Carlo generated photon spectra, and provide correlations between the physical parameters of the plasma and the fit parameters of our analytic fit function. These allow us to construct Thomson thick Comptonization spectra without performing computer intensive Monte Carlo simulations of the high-Thomson-depth hybrid-plasma Comptonization problem. Our formulae can easily be used in data analysis packages such as XSPEC, thus rendering rapid $\\chi^2$ fitting of such spectra to real data feasible.
An Event-Driven Hybrid Molecular Dynamics and Direct Simulation Monte Carlo Algorithm
Donev, A; Garcia, A L; Alder, B J
2007-07-30
A novel algorithm is developed for the simulation of polymer chains suspended in a solvent. The polymers are represented as chains of hard spheres tethered by square wells and interact with the solvent particles with hard core potentials. The algorithm uses event-driven molecular dynamics (MD) for the simulation of the polymer chain and the interactions between the chain beads and the surrounding solvent particles. The interactions between the solvent particles themselves are not treated deterministically as in event-driven algorithms, rather, the momentum and energy exchange in the solvent is determined stochastically using the Direct Simulation Monte Carlo (DSMC) method. The coupling between the solvent and the solute is consistently represented at the particle level, however, unlike full MD simulations of both the solvent and the solute, the spatial structure of the solvent is ignored. The algorithm is described in detail and applied to the study of the dynamics of a polymer chain tethered to a hard wall subjected to uniform shear. The algorithm closely reproduces full MD simulations with two orders of magnitude greater efficiency. Results do not confirm the existence of periodic (cycling) motion of the polymer chain.
A hybrid approach to device integration on a genetic analysis platform
NASA Astrophysics Data System (ADS)
Brennan, Des; Jary, Dorothee; Kurg, Ants; Berik, Evgeny; Justice, John; Aherne, Margaret; Macek, Milan; Galvin, Paul
2012-10-01
Point-of-care (POC) systems require significant component integration to implement biochemical protocols associated with molecular diagnostic assays. Hybrid platforms where discrete components are combined in a single platform are a suitable approach to integration, where combining multiple device fabrication steps on a single substrate is not possible due to incompatible or costly fabrication steps. We integrate three devices each with a specific system functionality: (i) a silicon electro-wetting-on-dielectric (EWOD) device to move and mix sample and reagent droplets in an oil phase, (ii) a polymer microfluidic chip containing channels and reservoirs and (iii) an aqueous phase glass microarray for fluorescence microarray hybridization detection. The EWOD device offers the possibility of fully integrating on-chip sample preparation using nanolitre sample and reagent volumes. A key challenge is sample transfer from the oil phase EWOD device to the aqueous phase microarray for hybridization detection. The EWOD device, waveguide performance and functionality are maintained during the integration process. An on-chip biochemical protocol for arrayed primer extension (APEX) was implemented for single nucleotide polymorphism (SNiP) analysis. The prepared sample is aspirated from the EWOD oil phase to the aqueous phase microarray for hybridization. A bench-top instrumentation system was also developed around the integrated platform to drive the EWOD electrodes, implement APEX sample heating and image the microarray after hybridization.
NASA Astrophysics Data System (ADS)
Carruba, V.; Burns, J. A.; Bottke, W.; Morbidelli, A.
2000-10-01
Until recently the dynamical evolution of small bodies through the asteroid belt was predicted through Monte Carlo codes based on Öpik approach, using the method implemented by Arnold. Dones et al.(1999), however, showed that, as suspected for a decade, the Öpik code is actually unable to reproduce the results of direct numerical simulations whenever resonances or very close encounters with planets or massive asteroids were present. To gain further insight, they suggested to check Öpik simulations by performing direct integrations of at least a few particles for as long as possible. In this work we tried to evaluate the semimajor axis mobility of asteroids due to encounters with Ceres, Pallas, and Vesta by comparing a direct numerical simulation obtained by Morbidelli and Nesvorny against analogous results of an Öpik code. We studied whether the two methods give quantitative similar results. Morbidelli et al. used a Mercury simplectic integrator to compute the change in proper orbital elements of 300 asteroids, that we further subdivided in two subgroups, one of which lies in a region populated by strong resonances. We ran our code for t=10,20,...90 Myr and then calculated the standard deviation of the spread in semimajor axis of the objects in both simulations. The Öpik code predicts smaller values of standard deviation as t increases, as compared with numerical simulations, with a time dependence which is approximately 2 times that predicted by direct integrations. While no conclusive results yet emerge from this work, there are some indications that in regions far from resonances the Öpik code may provide useful hints about dynamical evolution of asteroid families.
A Flexible Model and a Hybrid Exact Method for Integrated Employee Timetabling and
Boyer, Edmond
improve production costs and employee satisfaction. However, the resulting problem has generally beenA Flexible Model and a Hybrid Exact Method for Integrated Employee Timetabling and Production and linear programming exact method is designed to solve a ba- sic integrated employee timetabling and job
Ring Shaped Motor-Integrated Electric Drive for Hybrid Electric Vehicles
Y. Tadros; J. Ranneberg; U. Schäfer
An electric drive with motor integrated power electronics for the use in hybrid electric vehicles is presented. Novel technologies and specially designed components to fulfil the excessive temperature and restricted space requirements are shown. They allow a low cost full integration of the electric drive in a passenger car power train. The converter has circular shape and is inserted in
Integration of LED chip within patch antenna geometry for hybrid FSO/RF communication
Huang, Zhaoran "Rena"
Integration of LED chip within patch antenna geometry for hybrid FSO/RF communication J. Liao, A mode communi- cation transmitter using a LED integrated within the geometry of a planar patch antenna on a shared substrate is demonstrated. An exper- imental FSO link is constructed with a bare die visible LED
Two-Center Two-Electron Spin-Spin and Spin-Orbit Hybrid Integrals
Robert L. Matcha; Gulzari Malli
1972-01-01
General expressions for the two-center hybrid integrals over Slater orbitals occurring in the evaluation of the spin-spin and spin-orbit interactions in diatomic molecules are derived. The final expressions are in the form of one-dimensional integrals over functions which are readily evaluated.
NASA Astrophysics Data System (ADS)
Lin, L. Y.; Lee, S. S.; Pister, K. S. J.; Wu, M. C.
1995-05-01
The first self-aligned hybrid integration of semiconductor edge-emitting lasers and three-dimensional micro-optics was demonstrated. New self-alignment structures and micro-optics were constructed integrally on a Si chip employing surface micromachining methods. The divergent beam from the semiconductor laser was effectively collimated using the micro-Fresnel lens. The hybrid integration of semiconductor lens and three-dimensional micro-optics including micro-lenses, mirrors and gratings allowed micro-optical systems to be fabricated on a single Si substrate.
Monte Carlo solution of the volume-integral equation of electromagnetic scattering
NASA Astrophysics Data System (ADS)
Peltoniemi, J.; Muinonen, K.
2014-07-01
Electromagnetic scattering is often the main physical process to be understood when interpreting the observations of asteroids, comets, and meteors. Modeling the scattering faces still many problems, and one needs to assess several different cases: multiple scattering and shadowing by the rough surface, multiple scattering inside a surface element, and single scattering by a small object. Our specific goal is to extend the electromagnetic techniques to larger and more complicated objects, and derive approximations taking into account the most important effects of waves. Here we experiment with Monte Carlo techniques: can they provide something new to solving the scattering problems? The electromagnetic wave equation in the presence of a scatterer of volume V and refractive index m, with an incident wave EE_0, including boundary conditions and the scattering condition at infinity, can be presented in the form of an integral equation EE(rr)(1+suski(rr) Q(?))-int_{V-V_?}ddrr' GG(rr-rr')suski(rr')EE(rr') =EE_0, where suski(rr)=m(rr)^2-1, Q(?)=-1/3+{cal O}(?^2)+{O'}(m^2?^2), {O}, and {O'} are some second- and higher-order corrections for the finite-size volume V_? of radius ? around the singularity and GG is the dyadic Green's function of the form GG(RR)={exp(im kR)}/{4? R}[unittensor(1+{im}/{R}-{1}/{R^2})-RRRR(1+{3im}/{R}-{3}/{R^2})]. In general, this is solved by extending the internal field in terms of some simple basis functions, e.g., plane or spherical waves or a cubic grid, approximating the integrals in a clever way, and determining the goodness of the solution somehow, e.g., moments or least square. Whatever the choice, the solution usually converges nicely towards a correct enough solution when the scatterer is small and simple, and diverges when the scatterer becomes too complicated. With certain methods, one can reach larger scatterers faster, but the memory and CPU needs can be huge. Until today, all successful solutions are based on more or less regular quadratures. Because of the oscillating singularity of the Green's function, the quadrature must match exactly the canceling patterns of the integrand, and any improper quadrature leads to large errors. Monte Carlo based integration appears thus a very bad choice, but we take the challenge, and formulate the integration applying a three-finger rule to catch the singularity. Our other selections are the least-squares technique and plane-wave basis, though both can be freely and easily changed. The singularity is treated fully numerically, and the radius ? is assumed so small that the correction terms do not contribute. Any other choice only worsens the accuracy, without a significant gain in speed. As with any other technique, we can solve small spheres of size x<5/|m| within an hour of processor time with about 1% accuracy for a large range of refractive indices. In speed, this technique does not compete with faster techniques such as ADDA, but in some random cases the accuracy can be even better (probably due to sub-optimal singularity formula in ADDA -- applying numerical integration also there could probably make ADDA winner in all the cases). We continue towards more complicated cases and multiple scattering to see, if some further improvements can be made.
Zhang, Wenli; Muck-Hausl, Martin; Wang, Jichang; Sun, Chuanbo; Gebbing, Maren; Miskey, Csaba; Ivics, Zoltan; Izsvak, Zsuzsanna; Ehrhardt, Anja
2013-01-01
We recently developed adenovirus/transposase hybrid-vectors utilizing the previously described hyperactive Sleeping Beauty (SB) transposase HSB5 for somatic integration and we could show stabilized transgene expression in mice and a canine model for hemophilia B. However, the safety profile of these hybrid-vectors with respect to vector dose and genotoxicity remains to be investigated. Herein, we evaluated this hybrid-vector system in C57Bl/6 mice with escalating vector dose settings. We found that in all mice which received the hyperactive SB transposase, transgene expression levels were stabilized in a dose-dependent manner and that the highest vector dose was accompanied by fatalities in mice. To analyze potential genotoxic side-effects due to somatic integration into host chromosomes, we performed a genome-wide integration site analysis using linker-mediated PCR (LM-PCR) and linear amplification-mediated PCR (LAM-PCR). Analysis of genomic DNA samples obtained from HSB5 treated female and male mice revealed a total of 1327 unique transposition events. Overall the chromosomal distribution pattern was close-to-random and we observed a random integration profile with respect to integration into gene and non-gene areas. Notably, when using the LM-PCR protocol, 27 extra-chromosomal integration events were identified, most likely caused by transposon excision and subsequent transposition into the delivered adenoviral vector genome. In total, this study provides a careful evaluation of the safety profile of adenovirus/Sleeping Beauty transposase hybrid-vectors. The obtained information will be useful when designing future preclinical studies utilizing hybrid-vectors in small and large animal models. PMID:24124483
Axel Hoefer; Oliver Buss; Maik Hennebach; Michael Schmid; Dieter Porsch
2014-11-12
MOCABA is a combination of Monte Carlo sampling and Bayesian updating algorithms for the prediction of integral functions of nuclear data, such as reactor power distributions or neutron multiplication factors. Similarly to the established Generalized Linear Least Squares (GLLS) methodology, MOCABA offers the capability to utilize integral experimental data to reduce the prior uncertainty of integral observables. The MOCABA approach, however, does not involve any series expansions and, therefore, does not suffer from the breakdown of first-order perturbation theory for large nuclear data uncertainties. This is related to the fact that, in contrast to the GLLS method, the updating mechanism within MOCABA is applied directly to the integral observables without having to "adjust" any nuclear data. A central part of MOCABA is the nuclear data Monte Carlo program NUDUNA, which performs random sampling of nuclear data evaluations according to their covariance information and converts them into libraries for transport code systems like MCNP or SCALE. What is special about MOCABA is that it can be applied to any integral function of nuclear data, and any integral measurement can be taken into account to improve the prediction of an integral observable of interest. In this paper we present two example applications of the MOCABA framework: the prediction of the neutron multiplication factor of a water-moderated PWR fuel assembly based on 21 criticality safety benchmark experiments and the prediction of the power distribution within a toy model reactor containing 100 fuel assemblies.
NASA Astrophysics Data System (ADS)
Blasone, R.; Madsen, H.; Rosbjerg, D.
2006-12-01
So far, limited attention has been given to uncertainty assessment (UA) of distributed and integrated hydrological models. The main reasons for this are the high computational burden required by running these models, the potentially huge number of parameters involved and the difficulties in aggregating multi-site and multi-variable objective measures. This work presents a UA application conducted on an integrated, spatially distributed hydrological model in an attempt to overcome these difficulties. The UA of the model response is assessed through a revised version of the Generalized Likelihood Uncertainty Estimation (GLUE) methodology in which the sampling method is improved by the use of an adaptive Markov Chain Monte Carlo method, the Shuffled Complex Evolution Metropolis (SCEM-UA) algorithm. The use of the SCEM-UA algorithm allows an efficient sampling of the region of the parameter space containing the best solutions. Hereby more reliable posterior distributions of model outputs and parameters can be obtained at a reduced computational cost in comparison to the use of an initial random sampling method. The MIKE SHE modeling software is employed to simulate the runoff and the groundwater responses of a Danish watershed, the Karup catchment. The calibration data consists of observations of groundwater elevation at 17 sites and of runoff measurements at the catchment outlet. An aggregation method based on a distance scale transformation is used to combine groundwater levels and runoff measurements into a single objective function that takes into account the different impact of the two types of data on the global optimized function. An initial sensitivity analysis is applied to reduce the dimensionality of the problem and thus reducing the total number of model runs: the parameters with a limited impact on the model response are fixed to their calibrated value, while the variation of the others, which are affecting the most the model response, is subjected to the UA.
A Hybrid Integrated Silicon Diode Array for Visible Earth-Horizon Sensing
F. Bachner; R. Cohen; W. McGonagle; A. Foyt
1974-01-01
An earth-horizon sensing device which operates principally in the visible portion of the spectrum has been designed as a hybrid integrated circuit. The circuit was fabricated and tested for use in the LES-8\\/9 communications satellites as part of the system which maintains the satellites' orientation with respect to earth. The hybrid circuit consists of four silicon chips mounted on a
Ultra-efficient 10 Gb/s hybrid integrated silicon photonic transmitter and receiver.
Zheng, Xuezhe; Patil, Dinesh; Lexau, Jon; Liu, Frankie; Li, Guoliang; Thacker, Hiren; Luo, Ying; Shubin, Ivan; Li, Jieda; Yao, Jin; Dong, Po; Feng, Dazeng; Asghari, Mehdi; Pinguet, Thierry; Mekis, Attila; Amberg, Philip; Dayringer, Michael; Gainsley, Jon; Moghadam, Hesam Fathi; Alon, Elad; Raj, Kannan; Ho, Ron; Cunningham, John E; Krishnamoorthy, Ashok V
2011-03-14
Using low parasitic microsolder bumping, we hybrid integrated efficient photonic devices from different platforms with advanced 40 nm CMOS VLSI circuits to build ultra-low power silicon photonic transmitters and receivers for potential applications in high performance inter/intra-chip interconnects. We used a depletion racetrack ring modulator with improved electro-optic efficiency to allow stepper optical photo lithography for reduced fabrication complexity. Integrated with a low power cascode 2 V CMOS driver, the hybrid silicon photonic transmitter achieved better than 7 dB extinction ratio for 10 Gbps operation with a record low power consumption of 1.35 mW. A received power penalty of about 1 dB was measured for a BER of 10(-12) compared to an off-the-shelf lightwave LiNOb3 transmitter, which comes mostly from the non-perfect extinction ratio. Similarly, a Ge waveguide detector fabricated using 130 nm SOI CMOS process was integrated with low power VLSI circuits using hybrid bonding. The all CMOS hybrid silicon photonic receiver achieved sensitivity of -17 dBm for a BER of 10(-12) at 10 Gbps, consuming an ultra-low power of 3.95 mW (or 395 fJ/bit in energy efficiency). The scalable hybrid integration enables continued photonic device improvements by leveraging advanced CMOS technologies with maximum flexibility, which is critical for developing ultra-low power high performance photonic interconnects for future computing systems. PMID:21445153
Murakami, Yohei; Takada, Shoji
2013-01-01
When exact values of model parameters in systems biology are not available from experiments, they need to be inferred so that the resulting simulation reproduces the experimentally known phenomena. For the purpose, Bayesian statistics with Markov chain Monte Carlo (MCMC) is a useful method. Biological experiments are often performed with cell population, and the results are represented by histograms. On another front, experiments sometimes indicate the existence of a specific bifurcation pattern. In this study, to deal with both type of such experimental results and information for parameter inference, we introduced functions to evaluate fitness to both type of experimental results, named quantitative and qualitative fitness measures respectively. We formulated Bayesian formula for those hybrid fitness measures (HFM), and implemented it to MCMC (MCMC-HFM). We tested MCMC-HFM first for a kinetic toy model with a positive feedback. Inferring kinetic parameters mainly related to the positive feedback, we found that MCMC-HFM reliably infer them with both qualitative and quantitative fitness measures. Then, we applied the MCMC-HFM to an apoptosis signal transduction network previously proposed. For kinetic parameters related to implicit positive feedbacks, which are important for bistability and irreversibility of the output, the MCMC-HFM reliably inferred these kinetic parameters. In particular, some kinetic parameters that have the experimental estimates were inferred without these data and the results were consistent with the experiments. Moreover, for some parameters, the mixed use of quantitative and qualitative fitness measures narrowed down the acceptable range of parameters. Taken together, our approach could reliably infer the kinetic parameters of the target systems. PMID:24086320
Drilling of hybrid metal matrix composites—Workpiece surface integrity
S. Basavarajappa; G. Chandramohan; M. Prabu; K. Mukund; M. Ashwin
2007-01-01
The main concern in the present study is the surface roughness variations on the drilled surface and extension of surface and sub-surface deformation due to drilling. The influence of different tools and cutting conditions on Al2219\\/15%SiCp and Al2219\\/15%SiCp-3%Graphite (hybrid) composites is investigated experimentally. The composites are fabricated by liquid metallurgy method. The drilling tests are conducted with carbide and coated
LEDGF Hybrids Efficiently Retarget Lentiviral Integration Into Heterochromatin
Gijsbers, Rik; Ronen, Keshet; Vets, Sofie; Malani, Nirav; De Rijck, Jan; McNeely, Melissa; Bushman, Frederic D; Debyser, Zeger
2010-01-01
Correction of genetic diseases requires integration of the therapeutic gene copy into the genome of patient cells. Retroviruses are commonly used as delivery vehicles because of their precise integration mechanism, but their use has led to adverse events in which vector integration activated proto-oncogenes and contributed to leukemogenesis. Here, we show that integration by lentiviral vectors can be targeted away from genes using an artificial tethering factor. During normal lentivirus infection, the host cell–encoded transcriptional coactivator lens epithelium–derived growth factor/p75 (LEDGF/p75) binds lentiviral integrase (IN), thereby targeting integration to active transcription units and increasing the efficiency of infection. We replaced the LEDGF/p75 chromatin interaction–binding domain with CBX1. CBX1 binds histone H3 di- or trimethylated on K9, which is associated with pericentric heterochromatin and intergenic regions. The chimeric protein supported efficient transduction of lentiviral vectors and directed the integration outside of genes, near bound CBX1. Despite integration in regions rich in epigenetic marks associated with gene silencing, lentiviral vector expression remained efficient. Thus, engineered LEDGF/p75 chimeras provide technology for controlling integration site selection by lentiviral vectors. PMID:20195265
Hybrid integrated tunable optical transmitter subsystem on a chip
Louay A. Eldada; Alexander Newburgh; Junichiro Fujita; Antonije M. Radojevic; Reinald Gerhardt
2002-01-01
The need for tunable optical transmitters in optical networking is growing at a rapid rate. A tunable optical transmitter is the combination of a tunable laser, an isolator, and a modulator. Although today lasers and modulators could be integrated together on a single chip, an integrated component of this type would not be useful because the absence of an isolator
Flight tests of a hybrid-centered integrated 3D perspective-view primary flight display
NASA Astrophysics Data System (ADS)
He, Gang; Feyereisen, Thea; Wilson, Blake; Wyatt, Sandy; Engels, Jary
2006-05-01
This paper describes flight tests of a Honeywell Synthetic Vision System (SVS) prototype operating in a hybrid-centered mode on a Primus Epic TM large format display. This novel hybrid mode effectively resolves some cognitive and perceptual human factors issues associated with traditional heading-up or track-up display modes. By integrating synthetic 3D perspective view with advanced Head-Up Display (HUD) symbology in this mode, the test results demonstrate that the hybrid display mode provides clear indications of current track and crab conditions, and is effective in overcoming flight guidance symbology collision and resultant ambiguity. The hybrid-centering SVS display concept is shown to be effective in all phases of flight and is particularly valuable during landing operations with a strong cross-wind. The recorded flight test data from Honeywell's prototype SVS concept at Reno, Nevada on board Honeywell Citation V aircraft will be discussed.
Hybrid organic-inorganic sol-gel materials and components for integrated optoelectronics
NASA Astrophysics Data System (ADS)
Lu, Dong
On the technical platform of hybrid organic-inorganic sol-gel, the integrated optoelectronics in the forms of heterogeneous integration between the hybrid sol-gel waveguide and the high refractive index semiconductors and the nonlinear functional doping of disperse red chromophore into hybrid sol-gel is developed. The structure of hybrid sol-gel waveguide on high index semiconductor substrate is designed with BPM-CAD software. A hybrid sol-gel based on MAPTMS and TEOS suitable for lower cladding for the waveguide is developed. The multi-layer hybrid sol-gel waveguide with good mode confinement and low polarization dependence is fabricated on Si and InP. As proof of concept, a 1 x 12 beam splitter based on multimode interference is fabricated on silicon substrate. The device shows excess loss below 0.65 dB and imbalance below 0.28 dB for both TE and TM polarization. A nonlinear active hybrid sol-gel doped with disperse red 13 has been developed by simple co-solvent method. It permits high loading concentration and has low optical loss at 1550 nm. The second-order nonlinear property of the active sol-gel is induced with corona poling and studied with second harmonic generation. A 3-fold of enhancement in the poling efficiency is achieved by blue light assisted corona poling. The chromophore alignment stability is improved by reducing the free volume of the formed inorganic network from the sol-gel condensation reaction. An active sol-gel channel waveguide has been fabricated using active and passive hybrid sol-gel materials by only photopatterning and spin-coating. An amplitude modulator based on the active sol-gel containing 30 wt.% of DR13 shows an electro-optic coefficient of 14 pm/V at 1550 nm and stable operation within the observation time of 24 days.
Design of integrated hybrid silicon waveguide optical gyroscope.
Srinivasan, Sudharsanan; Moreira, Renan; Blumenthal, Daniel; Bowers, John E
2014-10-20
We propose and analyze a novel highly integrated optical gyroscope using low loss silicon nitride waveguides. By integrating the active optical components on chip, we show the possibility of reaching a detection limit on the order of 19°/hr/?Hz in an area smaller than 10 cm(2). This study examines a number of parameters, including the dependence of sensitivity on sensor area. PMID:25401532
S. Mino; T. Ohyama; Y. Akahori; M. Yanagisawa; T. Hashimoto; Y. Yamada; H. Tsunetsugu; M. Togashi; Y. Itaya; Y. Shibata
1998-01-01
High-speed optoelectronic hybrid-integrated transmitter module has been developed using a silica-based planar lightwave circuit (PLC) platform on which a laser diode (LD) array and a two-channel LD driver IC were integrated. Heat absorption through a highly thermal conductive silicon terrace kept the average output power constant to within 5% during IC operation. Bit-error-rate (BER) measurement showed that this module operated
Integration of plug-in hybrid electric vehicles into building energy management system
Zhu Wang; Lingfeng Wang; Anastasios I. Dounis; Rui Yang
2011-01-01
The smart building and plug-in hybrid electric vehicle (PHEV) are two promising emerging technologies. The integration of these two technologies shows great promise in reinforcing the reliability and flexibility in building energy management. The control challenge of the smart building is to maximize the customer comfort with minimum power consumption. Multi-agent technology with particle swarm optimization (PSO) has been proposed
Lauermann, M.; Weimann, C.; Palmer, R.; Schindler, P. C. [Institute of Photonics and Quantum Electronics, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Koeber, S.; Freude, W., E-mail: christian.koos@kit.edu; Koos, C., E-mail: christian.koos@kit.edu [Institute of Photonics and Quantum Electronics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany and Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); Rembe, C. [Polytec GmbH, 76337 Waldbronn (Germany)
2014-05-27
We demonstrate a waveguide-based frequency shifter on the silicon photonic platform, enabling frequency shifts up to 10 GHz. The device is realized by silicon-organic hybrid (SOH) integration. Temporal shaping of the drive signal allows the suppression of spurious side-modes by more than 23 dB.
Demonstration of Orbital Angular Momentum State Conversion using Two Hybrid 3D Photonic Integrated
Kolner, Brian H.
Demonstration of Orbital Angular Momentum State Conversion using Two Hybrid 3D Photonic Integrated Ave, Murray Hill, NJ 07974, USA * sbyoo@ucdavis.edu Abstract: We demonstrate orbital angular momentum such SDM method, orbital angular momentum (OAM) has the advantage of using relatively simple cylindrically
Integration of Plug-In Hybrid Electric Vehicles into energy networks
Matthias D. Galus; G. Andersson
2009-01-01
Electrification of substantial percentages of individual transportation through Plug-In Hybrid Electric Vehicles (PHEVs) will lead to an integration of power and transport systems. This, in turn, will impose an additional demand on today's power system, potentially stressing hazardous for some pieces of equipment. Smart management schemes, investigated in this paper, can alleviate possible congestion issues in power systems by intelligently
The energy demand of distillation-molecular sieve systems for ethanol recovery/dehydration can be significant, particularly for dilute solutions. An alternative hybrid process integrating vapor stripping (like a beer still) with vapor compression and a vapor permeation membrane s...
Conceptual Integration of Hybridization by Algerian Students Intending to Teach Physical Sciences
ERIC Educational Resources Information Center
Salah, Hazzi; Dumon, Alain
2011-01-01
This work aims to assess the difficulties encountered by students of the Ecole Normale Superieure of Kouba (Algeria) intending to teach physical science in the integration of the hybridization of atomic orbitals. It is a concept that they should use in describing the formation of molecular orbitals ([sigma] and [pi]) in organic chemistry and gaps…
Masahiro Nakajima; Fumihito Arai; Lixin Dong; Toshio Fukuda
2004-01-01
A hybrid nanorobotic manipulation system, which is integrated with a nanorobotic manipulator inside a transmission electron microscope (TEM) and nanorobotic manipulators inside a scanning electron microscope (SEM), is presented. The TEM nanomanipulator has been constructed with 4 multi-layer piezoelectric devices for driving in 3 translational degrees of freedoms (DOFs) and a passive 3-DOF sample stage driven by SEM nanorobotic manipulators.
A hybrid integrated silicon diode array for visible earth-horizon sensing
F. J. Bachner; R. A. Cohen; W. H. McGonagle; A. G. Foyt
1974-01-01
The present work describes fabrication and stress testing results for a hybrid, integrated earth-horizon sensor operating principally in the visible portion of the spectrum. The sensor consists of four silicon chips each containing a linear array of eight photodiode. The diodes are planar, n+ on p, shallow junction devices which use a channel stop to prevent surface inversion between diodes
Sachin Jain; Vivek Agarwal
2008-01-01
A new, hybrid integrated topology, fed by photovoltaic (PV) and fuel cell (FC) sources and suitable for distributed generation applications, is proposed. It works as an uninterruptible power source that is able to feed a certain minimum amount of power into the grid under all conditions. PV is used as the primary source of power operating near maximum power point
Technology platform for hybrid integration of MOEMS on reconfigurable silicon micro-optical table
Paris-Sud XI, UniversitÃ© de
Technology platform for hybrid integration of MOEMS on reconfigurable silicon micro-optical table S CNRS 6174, Micro Nano Sciences and Systems (MN2S) departament, BesanÃ§on 25030, Franceb FEMTO of the proposed approach. The new method for measuring of position of assembled holder, based on laser
NASA Astrophysics Data System (ADS)
Franke, Brian C.; Kensek, Ronald P.; Prinja, Anil K.
2014-06-01
Stochastic-media simulations require numerous boundary crossings. We consider two Monte Carlo electron transport approaches and evaluate accuracy with numerous material boundaries. In the condensed-history method, approximations are made based on infinite-medium solutions for multiple scattering over some track length. Typically, further approximations are employed for material-boundary crossings where infinite-medium solutions become invalid. We have previously explored an alternative "condensed transport" formulation, a Generalized Boltzmann-Fokker-Planck GBFP method, which requires no special boundary treatment but instead uses approximations to the electron-scattering cross sections. Some limited capabilities for analog transport and a GBFP method have been implemented in the Integrated Tiger Series (ITS) codes. Improvements have been made to the condensed history algorithm. The performance of the ITS condensed-history and condensed-transport algorithms are assessed for material-boundary crossings. These assessments are made both by introducing artificial material boundaries and by comparison to analog Monte Carlo simulations.
Hybrid Integrated Label-Free Chemical and Biological Sensors
Mehrabani, Simin; Maker, Ashley J.; Armani, Andrea M.
2014-01-01
Label-free sensors based on electrical, mechanical and optical transduction methods have potential applications in numerous areas of society, ranging from healthcare to environmental monitoring. Initial research in the field focused on the development and optimization of various sensor platforms fabricated from a single material system, such as fiber-based optical sensors and silicon nanowire-based electrical sensors. However, more recent research efforts have explored designing sensors fabricated from multiple materials. For example, synthetic materials and/or biomaterials can also be added to the sensor to improve its response toward analytes of interest. By leveraging the properties of the different material systems, these hybrid sensing devices can have significantly improved performance over their single-material counterparts (better sensitivity, specificity, signal to noise, and/or detection limits). This review will briefly discuss some of the methods for creating these multi-material sensor platforms and the advances enabled by this design approach. PMID:24675757
Integrated Cost and Schedule using Monte Carlo Simulation of a CPM Model - 12419
Hulett, David T. [Hulett and Associates, LLC (United States); Nosbisch, Michael R. [Project Time and Cost, Inc. (United States)
2012-07-01
This discussion of the recommended practice (RP) 57R-09 of AACE International defines the integrated analysis of schedule and cost risk to estimate the appropriate level of cost and schedule contingency reserve on projects. The main contribution of this RP is to include the impact of schedule risk on cost risk and hence on the need for cost contingency reserves. Additional benefits include the prioritizing of the risks to cost, some of which are risks to schedule, so that risk mitigation may be conducted in a cost-effective way, scatter diagrams of time-cost pairs for developing joint targets of time and cost, and probabilistic cash flow which shows cash flow at different levels of certainty. Integrating cost and schedule risk into one analysis based on the project schedule loaded with costed resources from the cost estimate provides both: (1) more accurate cost estimates than if the schedule risk were ignored or incorporated only partially, and (2) illustrates the importance of schedule risk to cost risk when the durations of activities using labor-type (time-dependent) resources are risky. Many activities such as detailed engineering, construction or software development are mainly conducted by people who need to be paid even if their work takes longer than scheduled. Level-of-effort resources, such as the project management team, are extreme examples of time-dependent resources, since if the project duration exceeds its planned duration the cost of these resources will increase over their budgeted amount. The integrated cost-schedule risk analysis is based on: - A high quality CPM schedule with logic tight enough so that it will provide the correct dates and critical paths during simulation automatically without manual intervention. - A contingency-free estimate of project costs that is loaded on the activities of the schedule. - Resolves inconsistencies between cost estimate and schedule that often creep into those documents as project execution proceeds. - Good-quality risk data that are usually collected in risk interviews of the project team, management and others knowledgeable in the risk of the project. The risks from the risk register are used as the basis of the risk data in the risk driver method. The risk driver method is based in the fundamental principle that identifiable risks drive overall cost and schedule risk. - A Monte Carlo simulation software program that can simulate schedule risk, burn WM2012 rate risk and time-independent resource risk. The results include the standard histograms and cumulative distributions of possible cost and time results for the project. However, by simulating both cost and time simultaneously we can collect the cost-time pairs of results and hence show the scatter diagram ('football chart') that indicates the joint probability of finishing on time and on budget. Also, we can derive the probabilistic cash flow for comparison with the time-phased project budget. Finally the risks to schedule completion and to cost can be prioritized, say at the P-80 level of confidence, to help focus the risk mitigation efforts. If the cost and schedule estimates including contingency reserves are not acceptable to the project stakeholders the project team should conduct risk mitigation workshops and studies, deciding which risk mitigation actions to take, and re-run the Monte Carlo simulation to determine the possible improvement to the project's objectives. Finally, it is recommended that the contingency reserves of cost and of time, calculated at a level that represents an acceptable degree of certainty and uncertainty for the project stakeholders, be added as a resource-loaded activity to the project schedule for strategic planning purposes. The risk analysis described in this paper is correct only for the current plan, represented by the schedule. The project contingency reserve of time and cost that are the main results of this analysis apply if that plan is to be followed. Of course project managers have the option of re-planning and re-scheduling in the face of new facts, in part by m
Integrated antenna base station design for hybrid fibre radio networks
W. S. T. Rowe; R. B. Waterhouse; A. Nirmalathas; D. Novak
1999-01-01
A printed antenna structure suitable for integration with optoelectronic devices in the base station of fiber-radio networks is presented. The stacked patch antenna utilizes the semiconductor material and a low dielectric constant laminate to yield a broad bandwidth and high surface wave efficiency. Experimental verification of the printed antenna is given
El-Kady, Maher F; Ihns, Melanie; Li, Mengping; Hwang, Jee Youn; Mousavi, Mir F; Chaney, Lindsay; Lech, Andrew T; Kaner, Richard B
2015-04-01
Supercapacitors now play an important role in the progress of hybrid and electric vehicles, consumer electronics, and military and space applications. There is a growing demand in developing hybrid supercapacitor systems to overcome the energy density limitations of the current generation of carbon-based supercapacitors. Here, we demonstrate 3D high-performance hybrid supercapacitors and microsupercapacitors based on graphene and MnO2 by rationally designing the electrode microstructure and combining active materials with electrolytes that operate at high voltages. This results in hybrid electrodes with ultrahigh volumetric capacitance of over 1,100 F/cm(3). This corresponds to a specific capacitance of the constituent MnO2 of 1,145 F/g, which is close to the theoretical value of 1,380 F/g. The energy density of the full device varies between 22 and 42 Wh/l depending on the device configuration, which is superior to those of commercially available double-layer supercapacitors, pseudocapacitors, lithium-ion capacitors, and hybrid supercapacitors tested under the same conditions and is comparable to that of lead acid batteries. These hybrid supercapacitors use aqueous electrolytes and are assembled in air without the need for expensive "dry rooms" required for building today's supercapacitors. Furthermore, we demonstrate a simple technique for the fabrication of supercapacitor arrays for high-voltage applications. These arrays can be integrated with solar cells for efficient energy harvesting and storage systems. PMID:25831542
Integrating Adenovirus–Adeno-Associated Virus Hybrid Vectors Devoid of All Viral Genes
Lieber, André; Steinwaerder, Dirk S.; Carlson, Cheryl A.; Kay, Mark A.
1999-01-01
Recently, we demonstrated that inverted repeat sequences inserted into first-generation adenovirus (Ad) vector genomes mediate precise genomic rearrangements resulting in vector genomes devoid of all viral genes that are efficiently packaged into functional Ad capsids. As a specific application of this finding, we generated adenovirus–adeno-associated virus (AAV) hybrid vectors, first-generation Ad vectors containing AAV inverted terminal repeat sequences (ITRs) flanking a reporter gene cassette inserted into the E1 region. We hypothesized that the AAV ITRs present within the hybrid vector genome could mediate the formation of rearranged vector genomes (?Ad.AAV) and stimulate transgene integration. We demonstrate here that ?Ad.AAV vectors are efficiently generated as by-products of first-generation adenovirus-AAV vector amplification. ?Ad.AAV genomes contain only the transgene flanked by AAV ITRs, Ad packaging signals, and Ad ITRs. ?Ad.AAV vectors can be produced at a high titer and purity. In vitro transduction properties of these deleted hybrid vectors were evaluated in direct comparison with first-generation Ad and recombinant AAV vectors (rAAVs). The ?Ad.AAV hybrid vector stably transduced cultured cells with efficiencies comparable to rAAV. Since cells transduced with ?Ad.AAV did not express cytotoxic viral proteins, hybrid viruses could be applied at very high multiplicities of infection to increase transduction rates. Southern analysis and pulsed-field gel electrophoresis suggested that ?Ad.AAV integrated randomly as head-to-tail tandems into the host cell genome. The presence of two intact AAV ITRs was crucial for the production of hybrid vectors and for transgene integration. ?Ad.AAV vectors, which are straightforward in their production, represent a promising tool for stable gene transfer in vitro and in vivo. PMID:10516040
Jody Hey; Rasmus Nielsen
2007-01-01
In 1988, Felsenstein described a framework for assessing the likelihood of a genetic data set in which all of the possible genealogical histories of the data are considered, each in proportion to their probability. Although not analytically solvable, several approaches, including Markov chain Monte Carlo methods, have been developed to find approximate solutions. Here, we describe an approach in which
The Markov chain Monte Carlo method: an approach to approximate counting and integration
Mark Jerrum; Alistair Sinclair
1996-01-01
In the area of statistical physics, Monte Carlo algorithms based on Markov chain simulation have been in use for many years. The validity of these algorithms depends cru- cially on the rate of convergence to equilibrium of the Markov chain being simulated. Unfortunately, the classical theory of stochastic processes hardly touches on the sort of non-asymptotic analysis required in this
Bayesian Estimates of Equation System Parameters: An Application of Integration by Monte Carlo
Tuen Kloek; Herman K van Dijk
1978-01-01
Monte Carlo (MC) is used to draw parameter values from a distribution defined on the structural parameter space of an equation system. Making use of the prior density, the likelihood, and Bayes' Theorem it is possible to estimate posterior moments of both structural and reduced form parameters. The MC method allows a rather liberal choice of prior distributions. The number
A Monte Carlo study to compare two recent modifications of the KPSS test for near integration
María-Isabel Ayuda; Antonio Aznar
2011-01-01
The objective of this article is to compare the size and power properties of two modifications of the KPSS test of Kwiatkowski et al. (1992) proposed by Sul et al. (2005) and by Harris et al. (2007), using Monte Carlo simulations, in order to decide which version to use in applied research. The two modifications have been proposed to deal
Monte Carlo Monte Carlo at Work by Gary D. Doolen and John Hendricks E very second nearly 10,000,000,000 "random" numbers are being generated on computers around the world for Monte Carlo solutions to problems hundreds of full-time careers invested in the fine art of generating Monte Carlo solutions--a livelihood
Hiroshi Mizuseki; Kenta Hongo; Yoshiyuki Kawazoe; Luc T. Wille
2002-01-01
A cluster growth and deposition model based on hybrid modeling is introduced to examine the experimental conditions of the cluster growth process in vacuum chamber and deposition process on substrate. This hybrid model is a simulation method including physical length and time scale characteristics of macro and microscale. We simulated the behavior of the cluster during the flight path by
Integration of Neuroscience and Endocrinology in Hybrid PBL Curriculum
NSDL National Science Digital Library
PhD J. Thomas Cunningham (University of Missouri-Columbia School of Medicine Dept. of Physiology)
2001-12-01
At the University of Missouri-Columbia, the medical school employs a problem-based learning curriculum that began in 1993. Since the curriculum was changed, student performance on step 1 of the United States Medical Licensing Examination has significantly increased from slightly below the national average to almost one-half a standard deviation above the national mean. In the first and second years, classes for students are organized in classes or blocks that are 8 wk long, followed by 1 wk for evaluation. Initially, basic science endocrinology was taught in the fourth block of the first year with immunology and molecular biology. Student and faculty evaluations of the curriculum indicated that endocrinology did not integrate well with the rest of the material taught in that block. To address these issues, basic science endocrinology was moved into another block with neurosciences. We integrate endocrinology with neurosciences by using the hypothalamus and its role in neuroendocrinology as a springboard for endocrinology. This is accomplished by using clinical cases with clear neuroscience and endocrinology aspects such as CushingÂ?s disease and multiple endocrine neoplastic syndrome type 1.
Jian Liu; Jian-Ming Jin
2001-01-01
A novel hybridization of the finite element (FE) and boundary integral methods is presented for an efficient and accurate numerical analysis of electromagnetic scattering and radiation problems. The proposed method derives an adaptive numerical absorbing boundary condition (ABC) for the finite element solution based on boundary integral equations. Unlike the standard finite element-boundary integral approach, the proposed method is free
Planar lightwave circuit platform with coplanar waveguide for opto-electronic hybrid integration
S. Mono; K. Yoshino; Y. Yamada; T. Terui; M. Yasu; K. Moriwaki
1995-01-01
We propose a planar lightwave circuit (PLC) platform constructed on a silica-on-terraced-silicon (STS) substrate for opto-electronic hybrid integration. This platform consists of an embedded silica PLC region, a terraced silicon region for optical device assembly, and a high-speed electrical circuit region. In the electrical circuit region, the coplanar waveguides (CPW) are prepared on a thick-silica\\/silicon substrate. This structure reduces the
Optimization of the dual energy-integration mechanism in a parallel-type hybrid vehicle
Sheng-Chung Tzeng; K. David Huang; Chia-Chang Chen
2005-01-01
This research has designed a new hybrid-electric system, which is characterized by two mechanisms: internal-combustion engine energy-distribution mechanism and dual energy-integration mechanism. The internal-combustion engine energy-distribution mechanism comprises a first pulley-set and a second pulley-set, whereby it is possible to adjust its radius ratio and change the output load according to the road-surface, output speed and corresponding load to maintain
Integrated Plasma Simulation of Lower Hybrid Current Drive in Tokamaks
NASA Astrophysics Data System (ADS)
Bonoli, P. T.; Wright, J. C.; Harvey, R. W.; Batchelor, D. B.; Berry, L. A.; Kessel, C. E.; Jardin, S. C.
2012-03-01
It has been shown in Alcator C-Mod that the onset time for sawteeth can be delayed significantly (up to 0.5 s) relative to ohmically heated plasmas, through the injection of off-axis LH current drive power [1]. We are simulating these experiments using the Integrated Plasma Simulator (IPS) [2], where the driven LH current density profiles are computed using a ray tracing component (GENRAY) and Fokker Planck code (CQL3D) [3] that are run in a tightly coupled time advance. The background plasma is evolved using the TSC transport code with the Porcelli sawtooth model [4]. Predictions of the driven LH current profiles will be compared with simpler ``reduced'' models for LHCD such as the LSC code which is implemented in TSC and which is also invoked within the IPS. [4pt] [1] C. E. Kessel et al, Bull. of the Am. Phys. Soc. 53, Poster PP6.00074 (2008). [0pt] [2] D. Batchelor et al, Journal of Physics: Conf. Series 125, 012039 (2008). [0pt] [3] R. W. Harvey and M. G. McCoy, Proc. of the IAEA Tech. Comm. Meeting on Simulation and Modeling of Therm. Plasmas, Montreal, Canada (1992). [0pt] [4] S. C. Jardin et al, J. Comp. Phys. 66, 481 (1986).
Ya-Ping Yang; Caird E. Rexroad; Jörg Schläpfer; James E. Womack
1998-01-01
We recently constructed a 5000-rad cattle whole-genome radiation hybrid panel with the primary objective of integrating linkage maps of microsatellites with evolutionarily conserved genes into one ordered map. This study utilized the panel to construct a radiation hybrid (RH) map of bovine chromosome 19 (BTA19). Twelve microsatellites from different cattle linkage maps, 15 coding genes, and 2 expressed sequence tags
A Programmable MicroFluidic Processor: Integrated and Hybrid Solutions
Rose, K A
2002-05-10
The Programmable Fluidic Processor (PFP), a device conceived of by researchers at MD Anderson Cancer Center, is a reconfigurable and programmable bio-chemical analysis system designed for handheld operation in a variety of applications. Unlike most microfluidic systems which utilize channels to control fluids, the PFP device is a droplet-based system. The device is based on dielectrophoresis; a fluid transport phenomenon that utilizes mismatched polarizability between a droplet and its medium to induce droplet mobility. In the device, sample carrying droplets are polarized by an array of electrodes, individually addressable by subsurface microelectronics. My research focused on the development of a polymer-based microfluidic injection system for injecting these droplets onto the electrode array. The first of two device generations fabricated at LLNL was designed using extensive research and modeling performed by MD Anderson and Coventor. Fabricating the first generation required several iterations and design changes in order to generate an acceptable device for testing. Difficulties in planar fabrication of the fluidic system and a narrow channel design necessitated these changes. The second generation device incorporated modifications of the previous generation and improved on deficiencies discovered during experimentation with the initial device. Extensive modeling of the injection channels and fluid storage chamber also aided in redesigning the device's microfluidic system. A micromolding technique with interlocking features enabled precise alignments and dimensional control, critical requirements for device optimization. Fabrication of a final device will be fully integrated with the polymer-based microfluidics bonded directly to the silicon-based microelectronics. The optimized design and process flow developed in the trial generations will readily transfer to this approach.
NASA Technical Reports Server (NTRS)
Zuffada, C.; Cwik, T.; Jamnejad, V.
1994-01-01
An efficient hybrid finite element-integral equation technique has recently being developed to model EM scattering from three-dimensional inhomogeneous penetrable bodies of arbitrary shape, and is currently being extended to treat radiation problems.
Ali, Fawaz; Waller, Ed
2014-10-01
There are numerous scenarios where radioactive particulates can be displaced by external forces. For example, the detonation of a radiological dispersal device in an urban environment will result in the release of radioactive particulates that in turn can be resuspended into the breathing space by external forces such as wind flow in the vicinity of the detonation. A need exists to quantify the internal (due to inhalation) and external radiation doses that are delivered to bystanders; however, current state-of-the-art codes are unable to calculate accurately radiation doses that arise from the resuspension of radioactive particulates in complex topographies. To address this gap, a coupled computational fluid dynamics and Monte Carlo radiation transport approach has been developed. With the aid of particulate injections, the computational fluid dynamics simulation models characterize the resuspension of particulates in a complex urban geometry due to air-flow. The spatial and temporal distributions of these particulates are then used by the Monte Carlo radiation transport simulation to calculate the radiation doses delivered to various points within the simulated domain. A particular resuspension scenario has been modeled using this coupled framework, and the calculated internal (due to inhalation) and external radiation doses have been deemed reasonable. GAMBIT and FLUENT comprise the software suite used to perform the Computational Fluid Dynamics simulations, and Monte Carlo N-Particle eXtended is used to perform the Monte Carlo Radiation Transport simulations. PMID:25162421
Urbic, T.; Holovko, M. F.
2011-01-01
Associative version of Henderson-Abraham-Barker theory is applied for the study of Mercedes–Benz model of water near hydrophobic surface. We calculated density profiles and adsorption coefficients using Percus-Yevick and soft mean spherical associative approximations. The results are compared with Monte Carlo simulation data. It is shown that at higher temperatures both approximations satisfactory reproduce the simulation data. For lower temperatures, soft mean spherical approximation gives good agreement at low and at high densities while in at mid range densities, the prediction is only qualitative. The formation of a depletion layer between water and hydrophobic surface was also demonstrated and studied. PMID:21992334
O'Brien, M J; Procassini, R J; Joy, K I
2009-03-09
Validation of the problem definition and analysis of the results (tallies) produced during a Monte Carlo particle transport calculation can be a complicated, time-intensive processes. The time required for a person to create an accurate, validated combinatorial geometry (CG) or mesh-based representation of a complex problem, free of common errors such as gaps and overlapping cells, can range from days to weeks. The ability to interrogate the internal structure of a complex, three-dimensional (3-D) geometry, prior to running the transport calculation, can improve the user's confidence in the validity of the problem definition. With regard to the analysis of results, the process of extracting tally data from printed tables within a file is laborious and not an intuitive approach to understanding the results. The ability to display tally information overlaid on top of the problem geometry can decrease the time required for analysis and increase the user's understanding of the results. To this end, our team has integrated VisIt, a parallel, production-quality visualization and data analysis tool into Mercury, a massively-parallel Monte Carlo particle transport code. VisIt provides an API for real time visualization of a simulation as it is running. The user may select which plots to display from the VisIt GUI, or by sending VisIt a Python script from Mercury. The frequency at which plots are updated can be set and the user can visualize the simulation results as it is running.
NASA Astrophysics Data System (ADS)
Krzakala, Florent; Rosso, Alberto; Semerjian, Guilhem; Zamponi, Francesco
2008-10-01
The cavity method is a well-established technique for solving classical spin models on sparse random graphs (mean-field models with finite connectivity). Laumann [Phys. Rev. B 78, 134424 (2008)] proposed recently an extension of this method to quantum spin-1/2 models in a transverse field, using a discretized Suzuki-Trotter imaginary-time formalism. Here we show how to take analytically the continuous imaginary-time limit. Our main technical contribution is an explicit procedure to generate the spin trajectories in a path-integral representation of the imaginary-time dynamics. As a side result we also show how this procedure can be used in simple heat bath Monte Carlo simulations of generic quantum spin models. The replica symmetric continuous-time quantum cavity method is formulated for a wide class of models and applied as a simple example on the Bethe lattice ferromagnet in a transverse field. The results of the methods are confronted with various approximation schemes in this particular case. On this system we performed quantum Monte Carlo simulations that confirm the exactness of the cavity method in the thermodynamic limit.
Hybrid integration of Fabry-Pérot cavity with waveguide photodetector on silicon substrate
NASA Astrophysics Data System (ADS)
Hu, Fuquan; Huang, Yongqing; Ren, Xiaomin; Duan, Xiaofeng; Zhang, Xu; Fan, Xinye; Wang, Wei; Shang, Yufeng; Cai, Shiwei
2013-06-01
This paper demonstrated a novel device which was fabricated by the integration of a Fabry-Pérot cavity with waveguide photodetectors on silicon substrate. The design of this device integrates two functions on a single semiconductor chip, which is a current trend to make the compact on-chip photonic system. Due to the introduction of waveguide photodetectors, the tradeoff between efficiency and bandwidth could be improved and these two important factors could be specified almost independently. The Fabry-Pérot cavity was grown by metal-organic chemical vapor deposition (MOCVD), which was used for wavelength selectivity. The waveguide photodetector fabricated by the wet etching technique was used for light detection. The peak wavelength of the hybrid integrated device was at 1538 nm. The full-width at half-maximum was about 0.3 nm, and a dark current of 3.2 nA was achieved at the reverse bias of 3.0 V.
Kirk, B.L.
1985-12-01
The ITS (Integrated Tiger Series) Monte Carlo code package developed at Sandia National Laboratories and distributed as CCC-467/ITS by the Radiation Shielding Information Center (RSIC) at Oak Ridge National Laboratory (ORNL) consists of eight codes - the standard codes, TIGER, CYLTRAN, ACCEPT; the P-codes, TIGERP, CYLTRANP, ACCEPTP; and the M-codes ACCEPTM, CYLTRANM. The codes have been adapted to run on the IBM 3081, VAX 11/780, CDC-7600, and Cray 1 with the use of the update emulator UPEML. This manual should serve as a guide to a user running the codes on IBM computers having 370 architecture. The cases listed were tested on the IBM 3033, under the MVS operating system using the VS Fortran Level 1.3.1 compiler.
Dornheim, Tobias; Filinov, Alexey; Bonitz, Michael
2015-01-01
Correlated fermions are of high interest in condensed matter (Fermi liquids, Wigner molecules), cold atomic gases and dense plasmas. Here we propose a novel approach to path integral Monte Carlo (PIMC) simulations of strongly degenerate non-ideal fermions at finite temperature by combining a fourth-order factorization of the density matrix with antisymmetric propagators, i.e., determinants, between all imaginary time slices. To efficiently run through the modified configuration space, we introduce a modification of the widely used continuous space worm algorithm, which allows for an efficient sampling at arbitrary system parameters. We demonstrate how the application of determinants achieves an effective blocking of permutations with opposite signs, leading to a significant relieve of the fermion sign problem. To benchmark the capability of our method regarding the simulation of degenerate fermions, we consider multiple electrons in a quantum dot and compare our results with other ab initio techniques, where ...
Boehm, M.C. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany); Ramirez, R. [Instituto de Ciencia de Materiales, Madrid (Spain)
1995-08-17
The dynamics of the carbon nuclei in the C{sub 60} molecule have been studied by the Feynman path-integral (PI) quantum Monte Carlo (QMC) simulations and within a harmonic oscillator approximation. The following finite-temperature properties have been calculated: kinetic, potential, and total energy, radial and angular distribution functions (rdf, adf) as well as parameters describing the degree of atomic de/localization. The possible influence of quantum fluctuations on microscopic electronic structure properties of superconducting fullerides is briefly mentioned. PI simulations as well as simple analytical results show that the spatial uncertainty of the C atoms in C{sub 60} is comparable to the difference between the lengths of the short and long CC bonds in the icosahedral molecule. Reliable agreement between PI-derived rdf and the experimental curve based on neutron diffraction data is observed. 50 refs., 8 figs.
NSDL National Science Digital Library
2013-05-02
World competition and stringent United States fuel economy goals, and emission regulations for the 21st century vehicles, have pressured the automotive industry to design and evaluate advanced automobiles at an accelerated rate. The industry consensus is that the Hybrid Electric Vehicle (HEV) represents the currently available technology for increasing propulsion system efficiency and decreasing pollutant emissions. However, HEVs operate much differently than conventional vehicles. Therefore, existing design techniques and guidelines developed for conventional powertrains do not apply well to hybrid vehicles. There is a need for training automotive technicians and engineers as well as educating students in this new and emergent technology of HEV. This paper describes a funded project whose goal is to fill this need by developing integrated learning system for HEV technology. This project targets engineering/engineering technology students in 4-year universities, automotive technology students in community colleges, automotive engineers and technicians in industries, and technology teachers in secondary schools.
Performance analysis of an OTEC plant and a desalination plant using an integrated hybrid cycle
Uehara, Haruo; Miyara, Akio; Ikegami, Yasuyuki [Saga Univ. (Japan); Nakaoka, Tsutomu [National Fisheries Univ., Simonoseki, Yamaguchi (Japan). Dept. of Marine Engineering
1996-05-01
A performance analysis of an OTEC plant using an integrated hybrid cycle (I-H OTEC Cycle) has been conducted. The I-H OTEC cycle is a combination of a closed-cycle OTEC plant and a spray flash desalination plant. In an I-H OTEC cycle, warm sea water evaporates the liquid ammonia in the OTEC evaporator, then enters the flash chamber and evaporates itself. The evaporated steam enters the desalination condenser and is condensed by the cold sea water passed through the OTEC condenser. The optimization of the I-H OTEC cycle is analyzed by the method of steepest descent. The total heat transfer area of heat exchangers per net power is used as an objective function. Numerical results are reported for a 10 MW I-H OTEC cycle with plate-type heat exchangers and ammonia as working fluid. The results are compared with those of a joint hybrid OTEC cycle (J-H OTEC Cycle).
Steve T. Winnall; A. C. Lindsay; Michael W. Austin; John Canning; Arnan Mitchell
2006-01-01
A compact means to separate microwave and millimeter-wave optical signals by RF frequency in real time is demonstrated. The approach is to employ an integrated optical Bragg grating Fabry-Perot (BGFP) device to spatially separate optically modulated microwave signals with high resolution. The compactness is achieved through the use of an integrated optical hybrid diffractive lens beam expander to provide the
Chen, Chia-Lin; Wang, Yuchuan; Lee, Jason J. S.; Tsui, Benjamin M. W.
2008-01-01
The authors developed and validated an efficient Monte Carlo simulation (MCS) workflow to facilitate small animal pinhole SPECT imaging research. This workflow seamlessly integrates two existing MCS tools: simulation system for emission tomography (SimSET) and GEANT4 application for emission tomography (GATE). Specifically, we retained the strength of GATE in describing complex collimator?detector configurations to meet the anticipated needs for studying advanced pinhole collimation (e.g., multipinhole) geometry, while inserting the fast SimSET photon history generator (PHG) to circumvent the relatively slow GEANT4 MCS code used by GATE in simulating photon interactions inside voxelized phantoms. For validation, data generated from this new SimSET-GATE workflow were compared with those from GATE-only simulations as well as experimental measurements obtained using a commercial small animal pinhole SPECT system. Our results showed excellent agreement (e.g., in system point response functions and energy spectra) between SimSET-GATE and GATE-only simulations, and, more importantly, a significant computational speedup (up to ?10-fold) provided by the new workflow. Satisfactory agreement between MCS results and experimental data were also observed. In conclusion, the authors have successfully integrated SimSET photon history generator in GATE for fast and realistic pinhole SPECT simulations, which can facilitate research in, for example, the development and application of quantitative pinhole and multipinhole SPECT for small animal imaging. This integrated simulation tool can also be adapted for studying other preclinical and clinical SPECT techniques. PMID:18697552
NASA Astrophysics Data System (ADS)
Sharma, Diksha; Badal, Andreu; Badano, Aldo
2012-04-01
The computational modeling of medical imaging systems often requires obtaining a large number of simulated images with low statistical uncertainty which translates into prohibitive computing times. We describe a novel hybrid approach for Monte Carlo simulations that maximizes utilization of CPUs and GPUs in modern workstations. We apply the method to the modeling of indirect x-ray detectors using a new and improved version of the code \\scriptsize{{MANTIS}}, an open source software tool used for the Monte Carlo simulations of indirect x-ray imagers. We first describe a GPU implementation of the physics and geometry models in fast\\scriptsize{{DETECT}}2 (the optical transport model) and a serial CPU version of the same code. We discuss its new features like on-the-fly column geometry and columnar crosstalk in relation to the \\scriptsize{{MANTIS}} code, and point out areas where our model provides more flexibility for the modeling of realistic columnar structures in large area detectors. Second, we modify \\scriptsize{{PENELOPE}} (the open source software package that handles the x-ray and electron transport in \\scriptsize{{MANTIS}}) to allow direct output of location and energy deposited during x-ray and electron interactions occurring within the scintillator. This information is then handled by optical transport routines in fast\\scriptsize{{DETECT}}2. A load balancer dynamically allocates optical transport showers to the GPU and CPU computing cores. Our hybrid\\scriptsize{{MANTIS}} approach achieves a significant speed-up factor of 627 when compared to \\scriptsize{{MANTIS}} and of 35 when compared to the same code running only in a CPU instead of a GPU. Using hybrid\\scriptsize{{MANTIS}}, we successfully hide hours of optical transport time by running it in parallel with the x-ray and electron transport, thus shifting the computational bottleneck from optical to x-ray transport. The new code requires much less memory than \\scriptsize{{MANTIS}} and, as a result, allows us to efficiently simulate large area detectors.
Integration of multisensor hybrid reasoners to support personal autonomy in the smart home.
Valero, Miguel Ángel; Bravo, José; Chamizo, Juan Manuel García; López-de-Ipiña, Diego
2014-01-01
The deployment of the Ambient Intelligence (AmI) paradigm requires designing and integrating user-centered smart environments to assist people in their daily life activities. This research paper details an integration and validation of multiple heterogeneous sensors with hybrid reasoners that support decision making in order to monitor personal and environmental data at a smart home in a private way. The results innovate on knowledge-based platforms, distributed sensors, connected objects, accessibility and authentication methods to promote independent living for elderly people. TALISMAN+, the AmI framework deployed, integrates four subsystems in the smart home: (i) a mobile biomedical telemonitoring platform to provide elderly patients with continuous disease management; (ii) an integration middleware that allows context capture from heterogeneous sensors to program environment's reaction; (iii) a vision system for intelligent monitoring of daily activities in the home; and (iv) an ontologies-based integrated reasoning platform to trigger local actions and manage private information in the smart home. The framework was integrated in two real running environments, the UPM Accessible Digital Home and MetalTIC house, and successfully validated by five experts in home care, elderly people and personal autonomy. PMID:25232910
Integration of Multisensor Hybrid Reasoners to Support Personal Autonomy in the Smart Home
Valero, Miguel Ángel; Bravo, José; Chamizo, Juan Manuel García; López-de-Ipiña, Diego
2014-01-01
The deployment of the Ambient Intelligence (AmI) paradigm requires designing and integrating user-centered smart environments to assist people in their daily life activities. This research paper details an integration and validation of multiple heterogeneous sensors with hybrid reasoners that support decision making in order to monitor personal and environmental data at a smart home in a private way. The results innovate on knowledge-based platforms, distributed sensors, connected objects, accessibility and authentication methods to promote independent living for elderly people. TALISMAN+, the AmI framework deployed, integrates four subsystems in the smart home: (i) a mobile biomedical telemonitoring platform to provide elderly patients with continuous disease management; (ii) an integration middleware that allows context capture from heterogeneous sensors to program environment's reaction; (iii) a vision system for intelligent monitoring of daily activities in the home; and (iv) an ontologies-based integrated reasoning platform to trigger local actions and manage private information in the smart home. The framework was integrated in two real running environments, the UPM Accessible Digital Home and MetalTIC house, and successfully validated by five experts in home care, elderly people and personal autonomy. PMID:25232910
Draft of M2 Report on Integration of the Hybrid Hydride Model into INL’s MBM Framework for Review
Tikare, Veena; Weck, Philippe F.; Schultz, Peter A.; Clark, Blythe; Glazoff, Michael; Homer, Eric
2014-07-01
This report documents the development, demonstration and validation of a mesoscale, microstructural evolution model for simulation of zirconium hydride {delta}-ZrH{sub 1.5} precipitation in the cladding of used nuclear fuels that may occur during long-term dry storage. While the Zr-based claddings are manufactured free of any hydrogen, they absorb hydrogen during service, in the reactor by a process commonly termed ‘hydrogen pick-up’. The precipitation and growth of zirconium hydrides during dry storage is one of the most likely fuel rod integrity failure mechanisms either by embrittlement or delayed hydride cracking of the cladding (Hanson et al., 2011). While the phenomenon is well documented and identified as a potential key failure mechanism during long-term dry storage (Birk et al., 2012 and NUREG/CR-7116), the ability to actually predict the formation of hydrides is poor. The model being documented in this work is a computational capability for the prediction of hydride formation in different claddings of used nuclear fuels. This work supports the Used Fuel Disposition Research and Development Campaign in assessing the structural engineering performance of the cladding during and after long-term dry storage. This document demonstrates a basic hydride precipitation model that is built on a recently developed hybrid Potts-phase field model that combines elements of Potts-Monte Carlo and the phase-field models (Homer et al., 2013; Tikare and Schultz, 2012). The model capabilities are demonstrated along with the incorporation of the starting microstructure, thermodynamics of the Zr-H system and the hydride formation mechanism.
Bowers, John
Integrated Hybrid Silicon Evanescent Racetrack Laser and Photodetector Alexander W. Fang, Richard silicon evanescent racetrack laser with integrated photodetectors has been demonstrated running continuousGaInAs-silicon evanescent laser based on a racetrack-resonator-topography[3]. The laser runs continuous-wave (c
Mashayekhi, S.; Razzaghi, M.; Tripak, O.
2014-01-01
A new numerical method for solving the nonlinear mixed Volterra-Fredholm integral equations is presented. This method is based upon hybrid functions approximation. The properties of hybrid functions consisting of block-pulse functions and Bernoulli polynomials are presented. The operational matrices of integration and product are given. These matrices are then utilized to reduce the nonlinear mixed Volterra-Fredholm integral equations to the solution of algebraic equations. Illustrative examples are included to demonstrate the validity and applicability of the technique. PMID:24523638
Vanessa Audette Lynch; Steven L. Mielke; Donald G. Truhlar
2004-01-01
Accurate quantum mechanical partition functions and absolute free energies of H2O2 are determined using a realistic potential energy surface [J. Koput, S. Carter, and N. C. Handy, J. Phys. Chem. A 102, 6325 (1998)] for temperatures ranging from 300 to 2400 K by using Monte Carlo path integral calculations with new, efficient polyatomic importance sampling methods. The path centroids are
ITS Version 6 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.
Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William
2008-04-01
ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of lineartime-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 6, the latest version of ITS, contains (1) improvements to the ITS 5.0 codes, and (2) conversion to Fortran 90. The general user friendliness of the software has been enhanced through memory allocation to reduce the need for users to modify and recompile the code.
Arunraj, N S; Mandal, Saptarshi; Maiti, J
2013-06-01
Modeling uncertainty during risk assessment is a vital component for effective decision making. Unfortunately, most of the risk assessment studies suffer from uncertainty analysis. The development of tools and techniques for capturing uncertainty in risk assessment is ongoing and there has been a substantial growth in this respect in health risk assessment. In this study, the cross-disciplinary approaches for uncertainty analyses are identified and a modified approach suitable for industrial safety risk assessment is proposed using fuzzy set theory and Monte Carlo simulation. The proposed method is applied to a benzene extraction unit (BEU) of a chemical plant. The case study results show that the proposed method provides better measure of uncertainty than the existing methods as unlike traditional risk analysis method this approach takes into account both variability and uncertainty of information into risk calculation, and instead of a single risk value this approach provides interval value of risk values for a given percentile of risk. The implications of these results in terms of risk control and regulatory compliances are also discussed. PMID:23567215
A hybrid approach to protein folding problem integrating constraint programming with local search
2010-01-01
Background The protein folding problem remains one of the most challenging open problems in computational biology. Simplified models in terms of lattice structure and energy function have been proposed to ease the computational hardness of this optimization problem. Heuristic search algorithms and constraint programming are two common techniques to approach this problem. The present study introduces a novel hybrid approach to simulate the protein folding problem using constraint programming technique integrated within local search. Results Using the face-centered-cubic lattice model and 20 amino acid pairwise interactions energy function for the protein folding problem, a constraint programming technique has been applied to generate the neighbourhood conformations that are to be used in generic local search procedure. Experiments have been conducted for a few small and medium sized proteins. Results have been compared with both pure constraint programming approach and local search using well-established local move set. Substantial improvements have been observed in terms of final energy values within acceptable runtime using the hybrid approach. Conclusion Constraint programming approaches usually provide optimal results but become slow as the problem size grows. Local search approaches are usually faster but do not guarantee optimal solutions and tend to stuck in local minima. The encouraging results obtained on the small proteins show that these two approaches can be combined efficiently to obtain better quality solutions within acceptable time. It also encourages future researchers on adopting hybrid techniques to solve other hard optimization problems. PMID:20122212
NASA Astrophysics Data System (ADS)
Wendland, D.; Ballenegger, V.; Alastuey, A.
2014-11-01
We compute two- and three-body cluster functions that describe contributions of composite entities, like hydrogen atoms, ions H-, H_2^+, and helium atoms, and also charge-charge and atom-charge interactions, to the equation of state of a hydrogen-helium mixture at low density. A cluster function has the structure of a truncated virial coefficient and behaves, at low temperatures, like a usual partition function for the composite entity. Our path integral Monte Carlo calculations use importance sampling to sample efficiently the cluster partition functions even at low temperatures where bound state contributions dominate. We also employ a new and efficient adaptive discretization scheme that allows one not only to eliminate Coulomb divergencies in discretized path integrals, but also to direct the computational effort where particles are close and thus strongly interacting. The numerical results for the two-body function agree with the analytically known quantum second virial coefficient. The three-body cluster functions are compared at low temperatures with familiar partition functions for composite entities.
NASA Astrophysics Data System (ADS)
Nagarajan, Adarsh; Shireen, Wajiha
2013-06-01
This paper proposes an approach for integrating Plug-In Hybrid Electric Vehicles (PHEV) to an existing residential photovoltaic system, to control and optimize the power consumption of residential load. Control involves determining the source from which residential load will be catered, where as optimization of power flow reduces the stress on the grid. The system built to achieve the goal is a combination of the existing residential photovoltaic system, PHEV, Power Conditioning Unit (PCU), and a controller. The PCU involves two DC-DC Boost Converters and an inverter. This paper emphasizes on developing the controller logic and its implementation in order to accommodate the flexibility and benefits of the proposed integrated system. The proposed controller logic has been simulated using MATLAB SIMULINK and further implemented using Digital Signal Processor (DSP) microcontroller, TMS320F28035, from Texas Instruments
Integration Issues of Cells into Battery Packs for Plug-in and Hybrid Electric Vehicles: Preprint
Pesaran, A. A.; Kim, G. H.; Keyser, M.
2009-05-01
The main barriers to increased market share of hybrid electric vehicles (HEVs) and commercialization of plug-in HEVs are the cost, safety, and life of lithium ion batteries. Significant effort is being directed to address these issues for lithium ion cells. However, even the best cells may not perform as well when integrated into packs for vehicles because of the environment in which vehicles operate. This paper discusses mechanical, electrical, and thermal integration issues and vehicle interface issues that could impact the cost, life, and safety of the system. It also compares the advantages and disadvantages of using many small cells versus a few large cells and using prismatic cells versus cylindrical cells.
Shang, Yu; Lin, Yu; Yu, Guoqiang, E-mail: guoqiang.yu@uky.edu [Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506 (United States); Li, Ting [Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506 (United States); State Key Laboratory for Electronic Thin Film and Integrated Device, University of Electronic Science and Technology of China, Chengdu 610054 (China); Chen, Lei; Toborek, Michal [Department of Neurosurgery, University of Kentucky, Lexington, Kentucky 40536 (United States)
2014-05-12
Conventional semi-infinite solution for extracting blood flow index (BFI) from diffuse correlation spectroscopy (DCS) measurements may cause errors in estimation of BFI (?D{sub B}) in tissues with small volume and large curvature. We proposed an algorithm integrating Nth-order linear model of autocorrelation function with the Monte Carlo simulation of photon migrations in tissue for the extraction of ?D{sub B}. The volume and geometry of the measured tissue were incorporated in the Monte Carlo simulation, which overcome the semi-infinite restrictions. The algorithm was tested using computer simulations on four tissue models with varied volumes/geometries and applied on an in vivo stroke model of mouse. Computer simulations shows that the high-order (N???5) linear algorithm was more accurate in extracting ?D{sub B} (errors?
Shang, Yu; Li, Ting; Chen, Lei; Lin, Yu; Toborek, Michal; Yu, Guoqiang
2014-05-12
Conventional semi-infinite solution for extracting blood flow index (BFI) from diffuse correlation spectroscopy (DCS) measurements may cause errors in estimation of BFI (?DB ) in tissues with small volume and large curvature. We proposed an algorithm integrating Nth-order linear model of autocorrelation function with the Monte Carlo simulation of photon migrations in tissue for the extraction of ?DB . The volume and geometry of the measured tissue were incorporated in the Monte Carlo simulation, which overcome the semi-infinite restrictions. The algorithm was tested using computer simulations on four tissue models with varied volumes/geometries and applied on an in vivo stroke model of mouse. Computer simulations shows that the high-order (N???5) linear algorithm was more accurate in extracting ?DB (errors?
Hirofumi Akagi
2007-01-01
This paper discusses a transformerless hybrid active filter integrated into the 6.6-kV, 1-MW adjustable-speed motor drive having a three-phase diode rectifier at the front end. The hybrid filter consists of an active filter using a three-level diode-clamped PWM converter rated at 60 kVA, and a 250-kVA passive filter tuned to the 7th-harmonic frequency. They are directly connected in series without
NASA Astrophysics Data System (ADS)
Rajagopal, S.; Huntington, J. L.; Niswonger, R. G.; Reeves, M.; Pohll, G.
2012-12-01
Modeling complex hydrologic systems requires increasingly complex models to sufficiently describe the physical mechanisms observed in the domain. Streamflow in our study area is primarily driven by climate, reservoirs, and surface and groundwater interactions. Hence in this study, we are using the coupled surface and groundwater flow model, GSFLOW, to simulate streamflow in the Truckee River basin, Nevada and California. To characterize this hydrologic system the model domain is discretized into ~10,500 grid cells of 300m resolution for which a priori parameter estimates from observed climate, soils, geology, and well logs along with parameters that are default were derived. Due to the high dimensionality of the problem, it is important to quantify model uncertainty from multiple sources (parameter, climate input). In the current study, we adopt a stepwise approach to calibrate the model and to quantify the uncertainty in the simulation of different hydro-meteorological fluxes. This approach is preferred firstly due to the availability of multiple observations such as precipitation, solar radiation, snow depth and snow water equivalent, remotely sensed snow cover, and observed streamflow. Secondly, by focusing on individual modules and the parameters associated with simulating one process (e.g. solar radiation) we reduce the parameter search space which improves the robustness of the search algorithm in identifying the global minimum. The Differential Evolution Adaptive Metropolis (DREAM) algorithm, which is a Markov Chain Monte Carlo (MCMC) sampler, is applied to the GSFLOW model in this step wise approach to quantify meteorological input and parameter uncertainty. Results from this approach, posterior parameter distributions for model parameters, and model uncertainty is presented. This analysis will not only produce a robust model, but will also help model developers understand non-linear relationships between model parameters and simulated processes.
Lin Wang; Bing Yu; Li-ping Sun; Lei Ren; Qi-qing Zhang
2008-01-01
Microsphere integrated gelatin-siloxane hybrid scaffolds were successfully synthesized by using a combined sol-gel processing,\\u000a post-gelation soaking and freeze-drying process. A bone-like apatite layer was able to form in the Ca2+-containing porous hybrids upon soaking in a simulated body fluid (SBF) up to 1 day. The rate of gentamicin sulfate (GS) release\\u000a from the GS-loaded gelatin-siloxane hybrid microsphere became constant after
NASA Astrophysics Data System (ADS)
Maiti, Saumen; Tiwari, R. K.
2009-11-01
Identification of rock boundaries and structural features from well log response is a fundamental problem in geological field studies. However, in a complex geologic situation, such as in the presence of crystalline rocks where metamorphisms lead to facies changes, it is not easy to discern accurate information from well log data using conventional artificial neural network (ANN) methods. Moreover inferences drawn by such methods are also found to be ambiguous because of the strong overlapping of well log signals, which are generally tainted with deceptive noise. Here, we have developed an alternative ANN approach based on Bayesian statistics using the concept of Hybrid Monte Carlo (HMC)/Markov Chain Monte Carlo (MCMC) inversion scheme for modeling the German Continental Deep Drilling Program (KTB) well log data. MCMC algorithm draws an independent and identically distributed (i.i.d) sample by Markov Chain simulation technique from posterior probability distribution using the principle of statistical mechanics in Hamiltonian dynamics. In this algorithm, each trajectory is updated by approximating the Hamiltonian differential equations through a leapfrog discrimination scheme. We examined the stability and efficiency of the HMC-based approach on “noisy” data assorted with different levels of colored noise. We also perform uncertainty analysis by estimating standard deviation (STD) error map of a posteriori covariance matrix at the network output of three types of lithofacies over the entire length of the litho section of KTB. Our analyses demonstrate that the HMC-based approach renders robust means for classification of complex lithofacies successions from the KTB borehole noisy signals, and hence may provide a useful guide for understanding the crustal inhomogeneity and structural discontinuity in many other tectonically critical and complex regions.
V. S. Filinov; Yu. B. Ivanov; M. Bonitz; V. E. Fortov; P. R. Levashov
2013-01-29
Based on the quasiparticle model of the quark-gluon plasma (QGP), a color quantum path-integral Monte-Carlo (PIMC) method for calculation of thermodynamic properties and -- closely related to the latter -- a Wigner dynamics method for calculation of transport properties of the QGP are formulated. The QGP partition function is presented in the form of a color path integral with a new relativistic measure instead of the Gaussian one traditionally used in the Feynman-Wiener path integral. It is shown that the PIMC method is able to reproduce the lattice QCD equation of state at zero baryon chemical potential at realistic model parameters (i.e. quasiparticle masses and coupling constant) and also yields valuable insight into the internal structure of the QGP. Our results indicate that the QGP reveals quantum liquid-like (rather than gas-like) properties up to the highest considered temperature of 525 MeV. The pair distribution functions clearly reflect the existence of gluon-gluon bound states, i.e. glueballs, at temperatures just above the phase transition, while meson-like $q\\bar{q}$ bound states are not found. The calculated self-diffusion coefficient agrees well with some estimates of the heavy-quark diffusion constant available from recent lattice data and also with an analysis of heavy-quark quenching in experiments on ultrarelativistic heavy ion collisions, however, appreciably exceeds other estimates. The lattice and heavy-quark-quenching results on the heavy-quark diffusion are still rather diverse. The obtained results for the shear viscosity are in the range of those deduced from an analysis of the experimental elliptic flow in ultrarelativistic heavy ions collisions, i.e. in terms the viscosity-to-entropy ratio, $1/4\\pi < \\eta/S < 2.5/4\\pi$, in the temperature range from 170 to 440 MeV.
Sharma, Diksha; Badano, Aldo [Division of Imaging and Applied Mathematics, Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States)
2013-03-15
Purpose: hybridMANTIS is a Monte Carlo package for modeling indirect x-ray imagers using columnar geometry based on a hybrid concept that maximizes the utilization of available CPU and graphics processing unit processors in a workstation. Methods: The authors compare hybridMANTIS x-ray response simulations to previously published MANTIS and experimental data for four cesium iodide scintillator screens. These screens have a variety of reflective and absorptive surfaces with different thicknesses. The authors analyze hybridMANTIS results in terms of modulation transfer function and calculate the root mean square difference and Swank factors from simulated and experimental results. Results: The comparison suggests that hybridMANTIS better matches the experimental data as compared to MANTIS, especially at high spatial frequencies and for the thicker screens. hybridMANTIS simulations are much faster than MANTIS with speed-ups up to 5260. Conclusions: hybridMANTIS is a useful tool for improved description and optimization of image acquisition stages in medical imaging systems and for modeling the forward problem in iterative reconstruction algorithms.
Quantum rotation of Rb2 (3 ? {u/+}) attached to HeN droplets: a path-integral Monte Carlo study
NASA Astrophysics Data System (ADS)
Rodríguez-Cantano, Rocío; Pérez de Tudela, Ricardo; López-Durán, David; González-Lezana, Tomás; Gianturco, Franco A.; Delgado-Barrio, Gerardo; Villarreal, Pablo
2013-06-01
Doped He N Rb2 (3 ? u +) systems, with N = 20 and 40, have been studied by means of a path integral Monte Carlo method at two different temperatures T = 1 K and 2 K. The impurity, Rb2, is assumed as a rigid rotor and results are compared with a previous analysis in which no rotational or translational degrees of freedom were taken into account. Quantum effects are observed to play a noticeable role accounting for the extra energy with respect to the fixed Rb2 case although differences between the two approaches do not seem to be as important as reported for some other dopants attached to helium droplets, such as OCS for example. Probability density distributions exhibit the same overall features as the non-rotating system, predicting the outer location of Rb2 with respect to the helium atoms. The stability of the two clusters under study at T = 2 K is uncertain: the energy of He20Rb2 is positive and for He40Rb2, the observed dependence on the confinements imposed on the system precludes definitive statements regarding its physical existence.
NASA Astrophysics Data System (ADS)
Cuccoli, Alessandro; Macchi, Alessandro; Pedrolli, Gaia; Tognetti, Valerio; Vaia, Ruggero
1995-05-01
We consider the problem of the extrapolation of path-integral Monte Carlo (PIMC) data to infinite Trotter number P. Finite-P data, being even functions of P, have high-P dependence that is generally well described by a quadratic fit, a0+a1P-2, where a0 is the exact quantum value. However, in order to get convergence it is often necessary to run PIMC codes with rather high P values, which implies long computer times and larger statistical errors of the data. It is well known that also for harmonic systems the finite-P data are not exact; nevertheless, they can be easily calculated by Gaussian quadrature. Starting from this observation, we suggest an easy way to correct PIMC data for anharmonic systems in order to take into account the harmonic part exactly, with strong improvement of the extrapolation to P=?. Lower Trotter numbers are thus required, with the advantages of computer-time saving and much better accuracy of the extrapolated values, without any change in the PIMC code. In order to demonstrate the effectiveness of the approach, we report finite-P data processing for a single anharmonic particle, whose finite-P data are obtained by the matrix-squaring method, and for a chain of atoms with Morse interaction.
NASA Astrophysics Data System (ADS)
Tang, Zhong; Liao, Daifa
According to the current control characters of hybrid active power filter (HAPF), the current control model of HAPF is designed. The fuzzy recursive integral PI control algorithm is presented when it is compared to conventional PI control method. The control algorithm is applied to auto-regulate the proportional and integral parameters of PI. Thus, the robustness and response speed is enhanced; the dynamic performance of the HAPF device is improved. Under Matlab/Simulink background, a fuzzy recursive integral PI controller is designed and it is applied in a HAPF model in PSCAD/EMTDC. The results prove the feasibility and effectiveness of this fuzzy recursive integral PI control algorithm.
Automatic on-chip RNA-DNA hybridization assay with integrated phase change microvalves
NASA Astrophysics Data System (ADS)
Weng, Xuan; Jiang, Hai; Wang, Junsheng; Chen, Shu; Cao, Honghe; Li, Dongqing
2012-07-01
An RNA-DNA hybridization assay microfluidic chip integrated with electrothermally actuated phase change microvalves for detecting pathogenic bacteria is presented in this paper. In order to realize the sequential loading and washing processes required in such an assay, gravity-based pressure-driven flow and phase-change microvalves were used in the microfluidic chip. Paraffin wax was used as the phase change material in the valves and thin film heaters were used to electrothermally actuate microvalves. Light absorption measured by a photodetector to determine the concentrations of the samples. The automatic control of the complete assay was implemented by a self-coded LabVIEW program. To examine the performance of this chip, Salmonella was used as a sample pathogen. Significantly, reduction in reagent/sample consumption (up to 20 folds) was achieved by this on-chip assay, compared with using the commercial test kit following the same protocol in conventional labs. The experimental results show that the quantitative detection can be obtained in approximately 26 min, and the detection limit is as low as 103 CFU ml-1. This RNA-DNA hybridization assay microfluidic chip shows an excellent potential in the development of a portable device for point-of-testing applications.
Wu, Chunxiao; Wyatt, Alexander W; Lapuk, Anna V; McPherson, Andrew; McConeghy, Brian J; Bell, Robert H; Anderson, Shawn; Haegert, Anne; Brahmbhatt, Sonal; Shukin, Robert; Mo, Fan; Li, Estelle; Fazli, Ladan; Hurtado-Coll, Antonio; Jones, Edward C; Butterfield, Yaron S; Hach, Faraz; Hormozdiari, Fereydoun; Hajirasouliha, Iman; Boutros, Paul C; Bristow, Robert G; Jones, Steven Jm; Hirst, Martin; Marra, Marco A; Maher, Christopher A; Chinnaiyan, Arul M; Sahinalp, S Cenk; Gleave, Martin E; Volik, Stanislav V; Collins, Colin C
2012-05-01
Next-generation sequencing is making sequence-based molecular pathology and personalized oncology viable. We selected an individual initially diagnosed with conventional but aggressive prostate adenocarcinoma and sequenced the genome and transcriptome from primary and metastatic tissues collected prior to hormone therapy. The histology-pathology and copy number profiles were remarkably homogeneous, yet it was possible to propose the quadrant of the prostate tumour that likely seeded the metastatic diaspora. Despite a homogeneous cell type, our transcriptome analysis revealed signatures of both luminal and neuroendocrine cell types. Remarkably, the repertoire of expressed but apparently private gene fusions, including C15orf21:MYC, recapitulated this biology. We hypothesize that the amplification and over-expression of the stem cell gene MSI2 may have contributed to the stable hybrid cellular identity. This hybrid luminal-neuroendocrine tumour appears to represent a novel and highly aggressive case of prostate cancer with unique biological features and, conceivably, a propensity for rapid progression to castrate-resistance. Overall, this work highlights the importance of integrated analyses of genome, exome and transcriptome sequences for basic tumour biology, sequence-based molecular pathology and personalized oncology. PMID:22294438
Hoefling, Martin; Lima, Nicola; Haenni, Dominik; Seidel, Claus A. M.; Schuler, Benjamin; Grubmüller, Helmut
2011-01-01
Förster Resonance Energy Transfer (FRET) experiments probe molecular distances via distance dependent energy transfer from an excited donor dye to an acceptor dye. Single molecule experiments not only probe average distances, but also distance distributions or even fluctuations, and thus provide a powerful tool to study biomolecular structure and dynamics. However, the measured energy transfer efficiency depends not only on the distance between the dyes, but also on their mutual orientation, which is typically inaccessible to experiments. Thus, assumptions on the orientation distributions and averages are usually made, limiting the accuracy of the distance distributions extracted from FRET experiments. Here, we demonstrate that by combining single molecule FRET experiments with the mutual dye orientation statistics obtained from Molecular Dynamics (MD) simulations, improved estimates of distances and distributions are obtained. From the simulated time-dependent mutual orientations, FRET efficiencies are calculated and the full statistics of individual photon absorption, energy transfer, and photon emission events is obtained from subsequent Monte Carlo (MC) simulations of the FRET kinetics. All recorded emission events are collected to bursts from which efficiency distributions are calculated in close resemblance to the actual FRET experiment, taking shot noise fully into account. Using polyproline chains with attached Alexa 488 and Alexa 594 dyes as a test system, we demonstrate the feasibility of this approach by direct comparison to experimental data. We identified cis-isomers and different static local environments as sources of the experimentally observed heterogeneity. Reconstructions of distance distributions from experimental data at different levels of theory demonstrate how the respective underlying assumptions and approximations affect the obtained accuracy. Our results show that dye fluctuations obtained from MD simulations, combined with MC single photon kinetics, provide a versatile tool to improve the accuracy of distance distributions that can be extracted from measured single molecule FRET efficiencies. PMID:21629703
Celik, Metin
2009-03-01
The International Safety Management (ISM) Code defines a broad framework for the safe management and operation of merchant ships, maintaining high standards of safety and environmental protection. On the other hand, ISO 14001:2004 provides a generic, worldwide environmental management standard that has been utilized by several industries. Both the ISM Code and ISO 14001:2004 have the practical goal of establishing a sustainable Integrated Environmental Management System (IEMS) for shipping businesses. This paper presents a hybrid design methodology that shows how requirements from both standards can be combined into a single execution scheme. Specifically, the Analytic Hierarchy Process (AHP) and Fuzzy Axiomatic Design (FAD) are used to structure an IEMS for ship management companies. This research provides decision aid to maritime executives in order to enhance the environmental performance in the shipping industry. PMID:19038488
NASA Astrophysics Data System (ADS)
Floryan, Caspar; Issadore, David; Westervelt, Robert
2010-03-01
Here we report a hybrid integrated-circuit/microfluidic device which can position, porate and fuse individual cells. Existing electroporation and fusion devices can only act on cells in bulk. Our device consists of a microarray of electrode pixels^1 and a grounded conducting plate. Cells were positioned with dielectrophoretic forces induced by the pixels and porated or fused with voltage pulses which caused a dielectric breakdown of the cell membrane. The device positioned cells with 10?m precision and porated or fused them with high yields. It is programmable and mass-parallelization on a single device enables bulk applications. ^1 T. Hunt, D. Issadore, R. Westervelt, Lab on a Chip, 2008, 8, 81-87.
Simulation of solar-powered ammonia-water integrated hybrid cooling system
Chinnappa, J.C.V. (James Cook Univ., Townsville 4811 (AU)); Wijeysundera, N.E. (Dept. of Mechanical and Production Engineering, National Univ. of Singapore (SG))
1992-05-01
a number of solar-operated air-conditioning systems based on the H{sub 2}O-LiBr absorption chiller were built, installed, and monitored. A systematic study at the University of Colorado has been published. This paper presents a simple cost-benefit analysis of the conventional vapor compression system (VCS), the vapor absorption system (VAS), and the integrated hybrid system (IHS). The cost of energy input to the VAS and the IHS were compared with the energy cost of the VCS that these solar-powered systems replace. It was found that cost savings can be realized with solar-powered systems, only after a critical overall solar fraction is exceeded. Typically, this value was about 0.7 for a VAS and about 0.12 for a IHS. These cost-benefit results provided the motivation for a more detailed study of the IHS. There has also been other efforts in this direction.
Song, Yong-Ha; Ahn, Sang-Joon Kenny; Kim, Min-Wu; Lee, Jeong-Oen; Hwang, Chi-Sun; Pi, Jae-Eun; Ko, Seung-Deok; Choi, Kwang-Wook; Park, Sang-Hee Ko; Yoon, Jun-Bo
2015-03-01
A hybrid complementary logic inverter consisting of a microelectromechanical system switch as a promising alternative for the p-type oxide thin film transistor (TFT) and an n-type oxide TFT is presented for ultralow power integrated circuits. These heterogeneous microdevices are monolithically integrated. The resulting logic device shows a distinctive voltage transfer characteristic curve, very low static leakage, zero-short circuit current, and exceedingly high voltage gain. PMID:25418881
Carl J. Wordelman; Umberto Ravaioli
2000-01-01
A particle-particle-particle-mesh (P3M) algorithm is integrated with the ensemble Monte Carlo (EMC) method for the treatment of carrier-impurity (c-i) and carrier-carrier (c-c) effects in semiconductor device simulation. Ionized impurities and charge carriers are treated granularly as opposed to the normal continuum methods and c-i and c-c interactions are calculated in three dimensions. The combined P3M-EMC method follows the approach of
Janice M. Nigro; Anjan Misra; Ivan Smirnov; Howard Colman; Chandi Griffin; Natalie Ozburn; Mingang Chen; Edward Pan; Dimpy Koul; Burt G. Feuerstein; Kenneth D. Aldape
2005-01-01
Glioblastoma, the most aggressive primary brain tumor in humans, exhibits a large degree of molecular heterogeneity. Understanding the molecular pathology of a tumor and its linkage to behavior is an important foundation for developing and evaluating approaches to clinical management. Here we integrate array-comparative genomic hybridization and array- based gene expression profiles to identify relationships between DNA copy number aberrations,
Paris-Sud XI, Université de
whereas the objective of employee timetabling is to maximize employee satisfaction (or to minimize labor process would allow to balance production costs and employee satisfaction in a better way. HoweverSolving an integrated employee timetabling and job-shop scheduling problem via hybrid branch
T. P. Bohn; R. D. Lorenz; E. R. Olson
2004-01-01
Current hybrid electric vehicles, such as the Toyota Prius, use integrated power electronics modules (IPEM) to reduce cost, package size and interconnects. The Prius' dual inverter module allows power to flow directly from generator drive to motor drive precluding external measurement of that branch current. A highly sensitive giant magneto resistive effect (GMR) point field detector is used for in-situ
NASA Astrophysics Data System (ADS)
Lindsay, A.; McCloskey, J.; Nalbant, S. S.; Simao, N.; Murphy, S.; NicBhloscaidh, M.; Steacy, S.
2013-12-01
Identifying fault sections where slip deficits have accumulated may provide a means for understanding sequences of large megathrust earthquakes. Stress accumulated during the interseismic period on locked sections of an active fault is stored as potential slip. Where this potential slip remains unreleased during earthquakes, a slip deficit can be said to have accrued. Analysis of the spatial distribution of slip during antecedent events along the fault will show where the locked plate has spent its stored slip and indicate where the potential for large events remains. The location of recent earthquakes and their distribution of slip can be estimated instrumentally. To develop the idea of long-term slip-deficit modelling it is necessary to constrain the size and distribution of slip for pre-instrumental events dating back hundreds of years covering more than one ';seismic cycle'. This requires the exploitation of proxy sources of data. Coral microatolls, growing in the intertidal zone of the outer island arc of the Sunda trench, present the possibility of producing high resolution reconstructions of slip for a number of pre-instrumental earthquakes. Their growth is influenced by tectonic flexing of the continental plate beneath them allows them to act as long term geodetic recorders. However, the sparse distribution of data available using coral geodesy results in a under determined problem with non-unique solutions. Instead of producing one definite model satisfying the observed corals displacements, a Monte Carlo Slip Estimator based on a Genetic Algorithm (MCSE-GA) accelerating the rate of convergence is used to identify a suite of models consistent with the data. Successive iterations of the MCSE-GA sample different displacements at each coral location, from within the spread of associated uncertainties, producing a catalog of models from the full range of possibilities. The suite of best slip distributions are weighted according to their fitness and stacked to produce a final estimate of the distribution of slip for a particular earthquake. Examination of the slip values in the stacked models allows areas of high confidence to be identified where the standard deviation is low. Similarly, areas of low confidence will be found where standard deviations are high. These high resolution models can be used to reconstruct a history of slip along the fault, both identifying and quantifying of slip deficits and constraining confidence in the accuracy of the modelled information. This presentation will demonstrate the ability of the MCSE-GA to produce accurate models of slip for instrumentally recorded earthquakes and show estimates for slip during paleoearthquakes along the Sunda Megathrust.
NSDL National Science Digital Library
David Joiner
Monte Carlo modeling refers to the solution of mathematical problems with the use of random numbers. This can include both function integration and the modeling of stochastic phenomena using random processes.
Electric-drive tractability indicator integrated in hybrid electric vehicle tachometer
Tamai, Goro; Zhou, Jing; Weslati, Feisel
2014-09-02
An indicator, system and method of indicating electric drive usability in a hybrid electric vehicle. A tachometer is used that includes a display having an all-electric drive portion and a hybrid drive portion. The all-electric drive portion and the hybrid drive portion share a first boundary which indicates a minimum electric drive usability and a beginning of hybrid drive operation of the vehicle. The indicated level of electric drive usability is derived from at least one of a percent battery discharge, a percent maximum torque provided by the electric drive, and a percent electric drive to hybrid drive operating cost for the hybrid electric vehicle.
First application close measurements applying the new hybrid integrated MEMS spectrometer
NASA Astrophysics Data System (ADS)
Grüger, Heinrich; Pügner, Tino; Knobbe, Jens; Schenk, Harald
2013-05-01
Grating spectrometers have been designed in many different configurations. Now potential high volume applications ask for extremely miniaturized and low cost systems. By the use of integrated MEMS (micro electro mechanical systems) scanning grating devices a less expensive single detector can be used in the NIR instead of the array detectors required for fixed grating systems. Meanwhile the design of a hybrid integrated MEMS scanning grating spectrometer has been drawn. The MEMS device was fabricated in the Fraunhofer IPMS own clean room facility. This chip is mounted on a small circuit board together with the detector and then stacked with spacer and mirror substrate. The spectrometer has been realized by stacking several planar substrates by sophisticated mounting technologies. The spectrometer has been designed for the 950nm - 1900nm spectral range and 9nm spectral resolution with organic matter analysis in mind. First applications are considered in the food quality analysis and food processing technology. As example for the use of a spectrometer with this performance the grill process of steak was analyzed. Similar measurement would be possible on dairy products, vegetables or fruit. The idea is a mobile spectrometer for in situ and on site analysis applications in or attached to a host system providing processing, data access and input-output capabilities, disregarding this would be a laptop, tablet, smart phone or embedded platform.
Advanced Hybrid Spacesuit Concept Featuring Integrated Open Loop and Closed Loop Ventilation Systems
NASA Technical Reports Server (NTRS)
Daniel, Brian A.; Fitzpatrick, Garret R.; Gohmert, Dustin M.; Ybarra, Rick M.; Dub, Mark O.
2013-01-01
A document discusses the design and prototype of an advanced spacesuit concept that integrates the capability to function seamlessly with multiple ventilation system approaches. Traditionally, spacesuits are designed to operate both dependently and independently of a host vehicle environment control and life support system (ECLSS). Spacesuits that operate independent of vehicle-provided ECLSS services must do so with equipment selfcontained within or on the spacesuit. Suits that are dependent on vehicle-provided consumables must remain physically connected to and integrated with the vehicle to operate properly. This innovation is the design and prototype of a hybrid spacesuit approach that configures the spacesuit to seamlessly interface and integrate with either type of vehicular systems, while still maintaining the ability to function completely independent of the vehicle. An existing Advanced Crew Escape Suit (ACES) was utilized as the platform from which to develop the innovation. The ACES was retrofitted with selected components and one-off items to achieve the objective. The ventilation system concept was developed and prototyped/retrofitted to an existing ACES. Components were selected to provide suit connectors, hoses/umbilicals, internal breathing system ducting/ conduits, etc. The concept utilizes a lowpressure- drop, high-flow ventilation system that serves as a conduit from the vehicle supply into the suit, up through a neck seal, into the breathing helmet cavity, back down through the neck seal, out of the suit, and returned to the vehicle. The concept also utilizes a modified demand-based breathing system configured to function seamlessly with the low-pressure-drop closed-loop ventilation system.
Menotti-Raymond, M; David, V A; Roelke, M E; Chen, Z Q; Menotti, K A; Sun, S; Schäffer, A A; Tomlin, J F; Agarwala, R; O'Brien, S J; Murphy, W J
2003-01-01
We report construction of second-generation integrated genetic linkage and radiation hybrid (RH) maps in the domestic cat (Felis catus) that exhibit a high level of marker concordance and provide near-full genome coverage. A total of 864 markers, including 585 coding loci (type I markers) and 279 polymorphic microsatellite loci (type II markers), are now mapped in the cat genome. We generated the genetic linkage map utilizing a multigeneration interspecies backcross pedigree between the domestic cat and the Asian leopard cat (Prionailurus bengalensis). Eighty-one type I markers were integrated with 247 type II markers from a first-generation map to generate a map of 328 loci (320 autosomal and 8 X-linked) distributed in 47 linkage groups, with an average intermarker spacing of 8 cM. Genome coverage spans approximately 2,650 cM, allowing an estimate for the genetic length of the sex-averaged map as 3,300 cM. The 834-locus second-generation domestic cat RH map was generated from the incorporation of 579 type I and 255 type II loci. Type I markers were added using targeted selection to cover either genomic regions underrepresented in the first-generation map or to refine breakpoints in human/feline synteny. The integrated linkage and RH maps reveal approximately 110 conserved segments ordered between the human and feline genomes, and provide extensive anchored reference marker homologues that connect to the more gene dense human and mouse sequence maps, suitable for positional cloning applications. PMID:12692169
ERIC Educational Resources Information Center
Rodriguez-Keyes, Elizabeth; Schneider, Dana A.
2013-01-01
This study illustrates an experience of implementing a hybrid model for teaching human behavior in the social environment in an urban university setting. Developing a hybrid model in a BSW program arose out of a desire to reach students in a different way. Designed to promote curiosity and active learning, this particular hybrid model has students…
Hybrid integration of III-V and silicon materials and devices
NASA Astrophysics Data System (ADS)
Luo, Zhongsheng
Laser liftoff (LLO) based hybrid integration techniques including the double-transfer process and the pixel-to-point transfer process have been developed to integrate III-V photonics with silicon materials and circuitry. No degradation in the device performance has been observed using the LLO based transfer techniques. On the contrary, performance improvements in both electrical characteristics and electroluminescence (EL) output have been found for the (In,Ga)N light emitting diodes (LEDs) transferred onto Si substrate. Based on computer simulation, it is found that as much as 70% enhancement in EL output could be expected by optimizing the metal layering on the backside of the transferred LEDs. In order to understand the existing experimental data and improve controllability and damage-free transfer yield of the LLO process, a novel, comprehensive LLO model based on thermal-mechanical analysis has been proposed and developed. The LLO model has been validated in the well-studied GaN/sapphire system. By employing the LLO based transfer technique, two optoelectronic systems have been designed and demonstrated. The first one is an integrated fluorescence microsystem, which involved the integration of Cd(S,Se) bandgap filters, (In,Ga)N LEDs, Poly(dimethylsiloxane) (PDMS) microfluidic channels with a pre-fabricated Si PIN photodiode chip. Prototypes with both one color (blue LED) excitation and two-color (blue and green LED) excitation have consistently demonstrated a detection capability of as low as 1 nM fluosphere beads using Molecular Probes FluoSpheresRTM dye. Furthermore, the feasibility of multi-wavelength design has been verified using the bi-wavelength prototype. To optimize signal-to-noise ratio and detection sensitivity of the microsystem via system design, an in-depth mathematic analysis has also been performed. The second application is a zero-footprint optical metrology wafer, which relies on the reflection at the optical detection window, through which important parameters such as thickness, refractive index and density of the film on top of the detecting window can be probed in a real-time and location-specific manner. A novel methodology has been developed to ensure accurate and precise measurement across the wafer. A prototype wafer with 3x3 metrology cells has been prototyped and calibrated using a SF6 plasma etching process of silicon oxide.
NASA Astrophysics Data System (ADS)
Griesheimer, D. P.; Gill, D. F.; Nease, B. R.; Sutton, T. M.; Stedry, M. H.; Dobreff, P. S.; Carpenter, D. C.; Trumbull, T. H.; Caro, E.; Joo, H.; Millman, D. L.
2014-06-01
MC21 is a continuous-energy Monte Carlo radiation transport code for the calculation of the steady-state spatial distributions of reaction rates in three-dimensional models. The code supports neutron and photon transport in fixed source problems, as well as iterated-fission-source (eigenvalue) neutron transport problems. MC21 has been designed and optimized to support large-scale problems in reactor physics, shielding, and criticality analysis applications. The code also supports many in-line reactor feedback effects, including depletion, thermal feedback, xenon feedback, eigenvalue search, and neutron and photon heating. MC21 uses continuous-energy neutron/nucleus interaction physics over the range from 10-5 eV to 20 MeV. The code treats all common neutron scattering mechanisms, including fast-range elastic and non-elastic scattering, and thermal- and epithermal-range scattering from molecules and crystalline materials. For photon transport, MC21 uses continuous-energy interaction physics over the energy range from 1 keV to 100 GeV. The code treats all common photon interaction mechanisms, including Compton scattering, pair production, and photoelectric interactions. All of the nuclear data required by MC21 is provided by the NDEX system of codes, which extracts and processes data from EPDL-, ENDF-, and ACE-formatted source files. For geometry representation, MC21 employs a flexible constructive solid geometry system that allows users to create spatial cells from first- and second-order surfaces. The system also allows models to be built up as hierarchical collections of previously defined spatial cells, with interior detail provided by grids and template overlays. Results are collected by a generalized tally capability which allows users to edit integral flux and reaction rate information. Results can be collected over the entire problem or within specific regions of interest through the use of phase filters that control which particles are allowed to score each tally. The tally system has been optimized to maintain a high level of efficiency, even as the number of edit regions becomes very large.
NASA Astrophysics Data System (ADS)
Romero-García, S.; Marzban, B.; Sharif Azadeh, S.; Merget, F.; Shen, B.; Witzens, J.
2014-05-01
Hybrid integration of prefabricated III-V laser diodes with sub-micrometric silicon photonic waveguides suffers from a tradeoff between alignment tolerance and coupling efficiency. In this work, we demonstrate integrated coupling devices that substantially alleviate this problem by means of a balanced distribution of the laser power between two on-chip single mode SOI waveguides. With the reported coupling devices, a horizontal misalignment of the laser is converted in a variation of the relative phase of the light coupled into the two waveguides, allowing to satisfy the reciprocity principle while maintaining a high total coupling efficiency and a balanced power splitting. The relaxed alignment tolerances facilitate passive assembly of the lasers with pick-and-place tools. The balanced splitting of the power between waveguides is particularly well suited for optical interconnects with parallel transmitters. Here, the device design is discussed for both edge couplers and grating couplers relying on similar design principles. Furthermore, experimental characterization of edge-coupling structures with a lensed fiber and a Fabry-Pérot laser is presented. These devices have been fabricated with 193nm DUV optical lithography and are compatible with mainstream CMOS technology. The edge couplers with the best horizontal misalignment exhibits an excellent 1 dB loss horizontal misalignment range of 3.8 ?m with excess insertion losses below 3.1 dB (in addition to the 3dB splitting). The back-reflection induced by the device has been assessed to be below -20 dB and measured relative intensity noise is better than measured from the same laser coupled to a lensed fiber.
Bio-hybrid integrated system for wide-spectrum solar energy harvesting
NASA Astrophysics Data System (ADS)
Martin, Kathleen; Erdman, Matthew; Quintana, Hope; Shelnutt, John; Nogan, John; Swartzentruber, B.; Martinez, Julio; Lavrova, Olga; Busani, Tito
2014-03-01
An integrated hybrid photovoltaic-thermoelectric system has been developed using multiple layers of organic photosensitizers on inorganic semiconductors in order to efficiently convert UV-visible and IR energy into electricity. The hot anode of n-type ZnO nanowires was fabricated using a thermal process on pre-seeded layer and results to be crystalline with a transmittance up to 92 % and a bandgap of 3.32 eV. The visible-UV light-active organic layer was deposited between the anode and cathode at room temperature using a layer-by-layer deposition onto ITO and ZnO and Bi2Te3 nanowires from aqueous solution. The organic layer, a cooperative binary ionic (CBI) solid is composed of oppositely charged porphyrin metal (Zn(II) and Sn(IV)(OH-)2) derivatives that are separately water soluble, but when combined form a virtually insoluble solid. The electron donor/acceptor properties (energy levels, band gaps) of the solid can be controlled by the choice of metals and the nature of the peripheral substituent groups of the porphyrin ring. The highly thermoelectric structure, which acts as a cold cathode, is composed of p-type Bi2Te3 nanowires with a thermoelectric efficiency (ZT) between ~0.7 to 1, values that are twice that expected for bulk Bi2Te3. Efficiency of the integrated device, was found to be 35 at 0.2 suns illumination and thermoelectric properties are enhanced by the charge transfer between the CBI and the Bi2Te3 is presented in terms of photo- and thermogenerated current and advantages of the low cost fabrication process is discussed.
Yu, Longhai; Zheng, Jiajiu; Xu, Yang; Dai, Daoxin; He, Sailing
2014-11-25
Graphene is well-known as a two-dimensional sheet of carbon atoms arrayed in a honeycomb structure. It has some unique and fascinating properties, which are useful for realizing many optoelectronic devices and applications, including transistors, photodetectors, solar cells, and modulators. To enhance light-graphene interactions and take advantage of its properties, a promising approach is to combine a graphene sheet with optical waveguides, such as silicon nanophotonic wires considered in this paper. Here we report local and nonlocal optically induced transparency (OIT) effects in graphene-silicon hybrid nanophotonic integrated circuits. A low-power, continuous-wave laser is used as the pump light, and the power required for producing the OIT effect is as low as ?0.1 mW. The corresponding power density is several orders lower than that needed for the previously reported saturated absorption effect in graphene, which implies a mechanism involving light absorption by the silicon and photocarrier transport through the silicon-graphene junction. The present OIT effect enables low power, all-optical, broadband control and sensing, modulation and switching locally and nonlocally. PMID:25372937
T.F. Eibert; J.L. Volakis; Y.E. Erdemli
2002-03-03
Hybrid finite element (FE)--boundary integral (BI) analysis of infinite periodic arrays is extended to include planar multilayered Green's functions. In this manner, a portion of the volumetric dielectric region can be modeled via the finite element method whereas uniform multilayered regions can be modeled using a multilayered Green's function. As such, thick uniform substrates can be modeled without loss of efficiency and accuracy. The multilayered Green's function is analytically computed in the spectral domain and the resulting BI matrix-vector products are evaluated via the fast spectral domain algorithm (FSDA). As a result, the computational cost of the matrix-vector products is kept at O(N). Furthermore, the number of Floquet modes in the expansion are kept very few by placing the BI surfaces within the computational unit cell. Examples of frequency selective surface (FSS) arrays are analyzed with this method to demonstrate the accuracy and capability of the approach. One example involves complicated multilayered substrates above and below an inhomogeneous filter element and the other is an optical ring-slot array on a substrate several hundred wavelengths in thickness. Comparisons with measurements are included.
Fabrication of reproducible, integration-compatible hybrid molecular/si electronics.
Yu, Xi; Lovrin?i?, Robert; Kraynis, Olga; Man, Gabriel; Ely, Tal; Zohar, Arava; Toledano, Tal; Cahen, David; Vilan, Ayelet
2014-12-29
Reproducible molecular junctions can be integrated within standard CMOS technology. Metal-molecule-semiconductor junctions are fabricated by direct Si-C binding of hexadecane or methyl-styrene onto oxide-free H-Si(111) surfaces, with the lateral size of the junctions defined by an etched SiO2 well and with evaporated Pb as the top contact. The current density, J, is highly reproducible with a standard deviation in log(J) of 0.2 over a junction diameter change from 3 to 100 ?m. Reproducibility over such a large range indicates that transport is truly across the molecules and does not result from artifacts like edge effects or defects in the molecular monolayer. Device fabrication is tested for two n-Si doping levels. With highly doped Si, transport is dominated by tunneling and reveals sharp conductance onsets at room temperature. Using the temperature dependence of current across medium-doped n-Si, the molecular tunneling barrier can be separated from the Si-Schottky one, which is a 0.47 eV, in agreement with the molecular-modified surface dipole and quite different from the bare Si-H junction. This indicates that Pb evaporation does not cause significant chemical changes to the molecules. The ability to manufacture reliable devices constitutes important progress toward possible future hybrid Si-based molecular electronics. PMID:25098545
NASA Astrophysics Data System (ADS)
Bonoli, P. T.; Shiraiwa, S.; Wright, J. C.; Harvey, R. W.; Batchelor, D. B.; Berry, L. A.; Chen, Jin; Poli, F.; Kessel, C. E.; Jardin, S. C.
2012-10-01
Recent upgrades to the ion cyclotron RF (ICRF) and lower hybrid RF (LHRF) components of the Integrated Plasma Simulator [1] have made it possible to simulate LH current drive in the presence of ICRF minority heating and mode conversion electron heating. The background plasma is evolved in these simulations using the TSC transport code [2]. The driven LH current density profiles are computed using advanced ray tracing (GENRAY) and Fokker Planck (CQL3D) [3] components and predictions from GENRAY/CQL3D are compared with a ``reduced'' model for LHCD (the LSC [4] code). The ICRF TORIC solver is used for minority heating with a simplified (bi-Maxwellian) model for the non-thermal ion tail. Simulation results will be presented for LHCD in the presence of ICRF heating in Alcator C-Mod. [4pt] [1] D. Batchelor et al, Journal of Physics: Conf. Series 125, 012039 (2008).[0pt] [2] S. C. Jardin et al, J. Comp. Phys. 66, 481 (1986).[0pt] [3] R. W. Harvey and M. G. McCoy, Proc. of the IAEA Tech. Comm. Meeting on Simulation and Modeling of Therm. Plasmas, Montreal, Canada (1992).[0pt] [4] D. Ignat et al, Nucl. Fus. 34, 837 (1994).[0pt] [5] M. Brambilla, Plasma Phys. and Cont. Fusion 41,1 (1999).
NASA Technical Reports Server (NTRS)
Rothmann, Elizabeth; Dugan, Joanne Bechta; Trivedi, Kishor S.; Mittal, Nitin; Bavuso, Salvatore J.
1994-01-01
The Hybrid Automated Reliability Predictor (HARP) integrated Reliability (HiRel) tool system for reliability/availability prediction offers a toolbox of integrated reliability/availability programs that can be used to customize the user's application in a workstation or nonworkstation environment. The Hybrid Automated Reliability Predictor (HARP) tutorial provides insight into HARP modeling techniques and the interactive textual prompting input language via a step-by-step explanation and demonstration of HARP's fault occurrence/repair model and the fault/error handling models. Example applications are worked in their entirety and the HARP tabular output data are presented for each. Simple models are presented at first with each succeeding example demonstrating greater modeling power and complexity. This document is not intended to present the theoretical and mathematical basis for HARP.
NASA Astrophysics Data System (ADS)
Capelle, M.; Billoué, J.; Concord, J.; Poveda, P.; Gautier, G.
2014-02-01
This work presents the integration of a common mode filter with ElectroStatic Discharge protection on a silicon/porous silicon hybrid substrate. The porous silicon fabrication was performed after the integration of active components. Thus, a fluoropolymer hard mask was used to protect the active devices during anodization and can be easily removed without damaging the porous silicon. Electrical characterization results have shown fully operational components and an increase of performance with the hybrid substrate regarding to p+-type silicon. Indeed, the cutoff frequency was increased by 8.8 GHz when porous silicon was fabricated below the bump pads and the inductors. This improvement is a promising result to extend the application of RF components for future communication standards with silicon technology.
A suitable integral equation for the quasi-TEM analysis of hybrid strip\\/slot-like structures
Jesús Martel; Francisco Medina
2001-01-01
This paper reports on a suitable formulation of the spectral domain\\/integral-equation method for the quasi-TEM analysis of hybrid strip\\/slot-like planar lines. The free surface charge distribution is used as an unknown on the strip-like interface, whereas the electric field is used on the slot-like region. This formulation allows us to reduce the number of basis functions and makes possible a
Not Available
1982-04-19
The Project Integration Office (PIO) was established to assist the US DOE with the direction and coordination of its multiple electric vehicle and hybrid electric vehicle research programs in order to get the maximum payoff from these research efforts. In addition, the PIO performs objective independent technical and economic studies, analyses and modeling, and maintains a technical information liaison service to facilitate information exchange between the program participants and industry. Progress in each of these activities is reported. (LCL)
Bowers, John
Hybrid silicon photonic integrated circuits for optical networking E. F. Burmeister, H.-W. Chen, J hybrid silicon devices that combine benefits of III-V semiconductors with silicon-based platforms. Presented work includes a silicon-on-insulator evanescent phase modulator and a recirculating buffer using
Monte Carlo Neutrino Oscillations
James P. Kneller; Gail C. McLaughlin
2005-09-29
We demonstrate that the effects of matter upon neutrino propagation may be recast as the scattering of the initial neutrino wavefunction. Exchanging the differential, Schrodinger equation for an integral equation for the scattering matrix S permits a Monte Carlo method for the computation of S that removes many of the numerical difficulties associated with direct integration techniques.
NASA Astrophysics Data System (ADS)
Cramer, S. N.; Roussin, R. W.
1981-11-01
A Monte Carlo analysis of a time-dependent neutron and secondary gamma-ray integral experiment on a thick concrete and steel shield is presented. The energy range covered in the analysis is 15-2 MeV for neutron source energies. The multigroup MORSE code was used with the VITAMIN C 171-36 neutron-gamma-ray cross-section data set. Both neutron and gamma-ray count rates and unfolded energy spectra are presented and compared, with good general agreement, with experimental results.
Hybrid materials science: a promised land for the integrative design of multifunctional materials.
Nicole, Lionel; Laberty-Robert, Christel; Rozes, Laurence; Sanchez, Clément
2014-06-21
For more than 5000 years, organic-inorganic composite materials created by men via skill and serendipity have been part of human culture and customs. The concept of "hybrid organic-inorganic" nanocomposites exploded in the second half of the 20th century with the expansion of the so-called "chimie douce" which led to many collaborations between a large set of chemists, physicists and biologists. Consequently, the scientific melting pot of these very different scientific communities created a new pluridisciplinary school of thought. Today, the tremendous effort of basic research performed in the last twenty years allows tailor-made multifunctional hybrid materials with perfect control over composition, structure and shape. Some of these hybrid materials have already entered the industrial market. Many tailor-made multiscale hybrids are increasingly impacting numerous fields of applications: optics, catalysis, energy, environment, nanomedicine, etc. In the present feature article, we emphasize several fundamental and applied aspects of the hybrid materials field: bioreplication, mesostructured thin films, Lego-like chemistry designed hybrid nanocomposites, and advanced hybrid materials for energy. Finally, a few commercial applications of hybrid materials will be presented. PMID:24866174
Integrating Quality Matters into Hybrid Course Design: A Principles of Marketing Case Study
ERIC Educational Resources Information Center
Young, Mark R.
2014-01-01
Previous research supports the idea that the success of hybrid or online delivery modes is more a function of course design than delivery media. This article describes a case study of a hybrid Principles of Marketing course that implemented a comprehensive redesign based on design principles espoused by the Quality Matters Program, a center for…
A novel hybrid integrated wind-PV micro co-generation energy scheme for village electricity
Adel M. Sharaf; Mohamed A. H. El-Sayed
2009-01-01
A hybrid wind\\/PV system for supplying an isolated small community with electrical energy is digitally simulated and presented in this paper. The proposed hybrid renewable green energy scheme has four key subsystems or components to supply the required electric loads. The first subsystem includes the renewable generation sources from PV array and wind turbine. The second is the interface converters
Hybrid Environmental Control System Integrated Modeling Trade Study Analysis for Commercial Aviation
NASA Astrophysics Data System (ADS)
Parrilla, Javier
Current industry trends demonstrate aircraft electrification will be part of future platforms in order to achieve higher levels of efficiency in various vehicle level sub-systems. However electrification requires a substantial change in aircraft design that is not suitable for re-winged or re-engined applications as some aircraft manufacturers are opting for today. Thermal limits arise as engine cores progressively get smaller and hotter to improve overall engine efficiency, while legacy systems still demand a substantial amount of pneumatic, hydraulic and electric power extraction. The environmental control system (ECS) provides pressurization, ventilation and air conditioning in commercial aircraft, making it the main heat sink for all aircraft loads with exception of the engine. To mitigate the architecture thermal limits in an efficient manner, the form in which the ECS interacts with the engine will have to be enhanced as to reduce the overall energy consumed and achieve an energy optimized solution. This study examines a tradeoff analysis of an electric ECS by use of a fully integrated Numerical Propulsion Simulation System (NPSS) model that is capable of studying the interaction between the ECS and the engine cycle deck. It was found that a peak solution lays in a hybrid ECS where it utilizes the correct balance between a traditional pneumatic and a fully electric system. This intermediate architecture offers a substantial improvement in aircraft fuel consumptions due to a reduced amount of waste heat and customer bleed in exchange for partial electrification of the air-conditions pack which is a viable option for re-winged applications.
1-D EQUILIBRIUM DISCRETE DIFFUSION MONTE CARLO
T. EVANS; ET AL
2000-08-01
We present a new hybrid Monte Carlo method for 1-D equilibrium diffusion problems in which the radiation field coexists with matter in local thermodynamic equilibrium. This method, the Equilibrium Discrete Diffusion Monte Carlo (EqDDMC) method, combines Monte Carlo particles with spatially discrete diffusion solutions. We verify the EqDDMC method with computational results from three slab problems. The EqDDMC method represents an incremental step toward applying this hybrid methodology to non-equilibrium diffusion, where it could be simultaneously coupled to Monte Carlo transport.
Nair, Sithara S; McCullough, Eric J; Yadavalli, Vamsi K; Wynne, Kenneth J
2014-11-01
Investigating the surface characteristics of heterogeneous polymer systems is important for understanding how to better tailor surfaces and engineering specific reactions and desirable properties. Here we report on the surface properties for a blend consisting of a major component, a linear polyurethane or thermoplastic elastomer (TPU), and a minor component that is a hybrid network. The hybrid network consists of a fluorous polyoxetane soft block and a hydrolysis/condensation inorganic (HyCoin) network. Phase separation during coating formation results in surface concentration of the minor fluorous hybrid domain. The TPU is H12MDI/BD(50)-PTMO-1000 derived from bis(cyclohexylmethylene)-diisocyanate and butane diol (50 wt %) and poly(tetramethylene oxide). Surface modification results from a novel network-forming hybrid composed of poly(trifluoroethoxymethyl-methyl oxetane) diol) (3F) as the fluorous moiety end-capped with 3-isocyanatopropylriethoxysilane and bis(triethoxysilyl)ethane (BTESE) as a siliceous stabilizer. We use an integrated approach that combines elemental analysis of the near surface via X-ray photoelectron microscopy with surface mapping using atomic force microscopy that presents topographical and phase imaging along with nanomechanical properties. Overall, this versatile, high-resolution approach enabled unique insight into surface composition and morphology that led to a model of heterogeneous surfaces containing a range of constituents and properties. PMID:25268217
NASA Astrophysics Data System (ADS)
Hu, Fuquan; Huang, Yongqing; Duan, Xiaofeng; Zhang, Xu; Fan, Xinye; Shang, Yufeng; Cai, Shiwei; Wang, Wei; Ren, Xiaomin
2013-01-01
To integrate compound semiconductors with foreign substrates can lead to superior or novel functionalities. The design and fabrication of heterogeneously integrated waveguide photodetectors with Silicon-on-Insulator micro-ring resonator are reported in this paper. The micro-ring resonator was fabricated by utilizing electron beam lithography and inductively-coupled-plasma reactive ion etching technique, which is used for wavelength selectivity. The waveguide photodetectors fabricated by wet etching were used for light detection. The free spectral range (FSR) of the hybrid integrated device was about 24 nm, and the dark current of 7.9 nA was achieved at the reverse bias voltage of 2.0 V. The measured response of the photodetector at through port was 0.538 ?A/W at the wavelength of 1556 nm and a reverse bias of 1 V.
Primordial black hole seeding from hybrid inflation : the direct integration approach
Giguere, Alexis
2013-01-01
We examine the notion that supermassive black holes at the centre of galaxies, such as the Milky Way, could have been seeded in the early universe by the mechanisms of hybrid inflation. Using luminosity data, we estimate ...
Quantum Gibbs ensemble Monte Carlo
Riccardo Fantoni; Saverio Moroni
2014-08-24
We present a path integral Monte Carlo method which is the full quantum analogue of the Gibbs ensemble Monte Carlo method of Panagiotopoulos to study the gas-liquid coexistence line of a classical fluid. Unlike previous extensions of Gibbs ensemble Monte Carlo to include quantum effects, our scheme is viable even for systems with strong quantum delocalization in the degenerate regime of temperature. This is demonstrated by an illustrative application to the gas-superfluid transition of $^4$He in two dimensions.
Zhang, Wenli; Solanki, Manish; Müther, Nadine; Ebel, Melanie; Wang, Jichang; Sun, Chuanbo; Izsvak, Zsuzsanna; Ehrhardt, Anja
2013-01-01
Recombinant adeno-associated viral (AAV) vectors have been shown to be one of the most promising vectors for therapeutic gene delivery because they can induce efficient and long-term transduction in non-dividing cells with negligible side-effects. However, as AAV vectors mostly remain episomal, vector genomes and transgene expression are lost in dividing cells. Therefore, to stably transduce cells, we developed a novel AAV/transposase hybrid-vector. To facilitate SB-mediated transposition from the rAAV genome, we established a system in which one AAV vector contains the transposon with the gene of interest and the second vector delivers the hyperactive Sleeping Beauty (SB) transposase SB100X. Human cells were infected with the AAV-transposon vector and the transposase was provided in trans either by transient and stable plasmid transfection or by AAV vector transduction. We found that groups which received the hyperactive transposase SB100X showed significantly increased colony forming numbers indicating enhanced integration efficiencies. Furthermore, we found that transgene copy numbers in transduced cells were dose-dependent and that predominantly SB transposase-mediated transposition contributed to stabilization of the transgene. Based on a plasmid rescue strategy and a linear-amplification mediated PCR (LAM-PCR) protocol we analysed the SB100X-mediated integration profile after transposition from the AAV vector. A total of 1840 integration events were identified which revealed a close to random integration profile. In summary, we show for the first time that AAV vectors can serve as template for SB transposase mediated somatic integration. We developed the first prototype of this hybrid-vector system which with further improvements may be explored for treatment of diseases which originate from rapidly dividing cells. PMID:24116154
NASA Astrophysics Data System (ADS)
Srinivasan, P.; Priya, S.; Patel, Tarun; Gopalakrishnan, R. K.; Sharma, D. N.
2015-01-01
DD/DT fusion neutron generators are used as sources of 2.5 MeV/14.1 MeV neutrons in experimental laboratories for various applications. Detailed knowledge of the radiation dose rates around the neutron generators are essential for ensuring radiological protection of the personnel involved with the operation. This work describes the experimental and Monte Carlo studies carried out in the Purnima Neutron Generator facility of the Bhabha Atomic Research Center (BARC), Mumbai. Verification and validation of the shielding adequacy was carried out by measuring the neutron and gamma dose-rates at various locations inside and outside the neutron generator hall during different operational conditions both for 2.5-MeV and 14.1-MeV neutrons and comparing with theoretical simulations. The calculated and experimental dose rates were found to agree with a maximum deviation of 20% at certain locations. This study has served in benchmarking the Monte Carlo simulation methods adopted for shield design of such facilities. This has also helped in augmenting the existing shield thickness to reduce the neutron and associated gamma dose rates for radiological protection of personnel during operation of the generators at higher source neutron yields up to 1 × 1010 n/s.
Lee, R T; Liu, J K
2000-01-01
In this paper, we present an automatic and integrated neural network-based tropical cyclone (TC) identification and track mining system. The proposed system consists of two main modules: 1) TC pattern identification system using neural oscillatory elastic graph matching model (NOEGM); and 2) TC track mining system using hybrid radial basis function (HRBF) network with time difference and structural learning (TDSL) algorithm.For system evaluation, 120 TC cases appeared in the period between 1985 and 1998 provided by National Oceanic and Atmospheric Administration (NOAA) are being used. In TC pattern recognition from satellite pictures, an overall 98% of correct TC pattern segmentation rate and over 97% of correct classification rate are attained. Moreover, for TC track and intensity mining test, promising result of over 86% is achieved with the application of the hybrid RBF network. Comparing with the bureau numerical TC prediction model (OTCM) used by Guam and the enhanced model (TFS) proposed by Jeng et al., the proposed hybrid RBF has attained an over 30% and 18% improvement in forecast errors. PMID:18249795
Dixit, Manish K; Culp, Charles H; Fernandez-Solis, Jose L
2015-02-01
Buildings alone consume approximately 40% of the annual global energy and contribute indirectly to the increasing concentration of atmospheric carbon. The total life cycle energy use of a building is composed of embodied and operating energy. Embodied energy includes all energy required to manufacture and transport building materials, and construct, maintain, and demolish a building. For a systemic energy and carbon assessment of buildings, it is critical to use a whole life cycle approach, which takes into account the embodied as well as operating energy. Whereas the calculation of a building's operating energy is straightforward, there is a lack of a complete embodied energy calculation method. Although an input-output-based (IO-based) hybrid method could provide a complete and consistent embodied energy calculation, there are unresolved issues, such as an overdependence on price data and exclusion of the energy of human labor and capital inputs. This paper proposes a method for calculating and integrating the energy of labor and capital input into an IO-based hybrid method. The results demonstrate that the IO-based hybrid method can provide relatively complete results. Also, to avoid errors, the total amount of human and capital energy should not be excluded from the calculation. PMID:25561008
NASA Astrophysics Data System (ADS)
Inoue, Ryoichi; Abe, Tomoki; Fujimoto, Takeru; Ikadatsu, Noriyuki; Tanaka, Kenta; Uchida, Shigeto; Tazue, Akio; Kasada, Hirofumi; Ando, Koshi; Ichino, Kunio
2015-02-01
We have developed organic [poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)]–inorganic [ZnSSe] hybrid structure ultraviolet avalanche photodiodes (UV-APDs) with a long device lifetime and integrated APD arrays. The active layer is ZnSSe grown by molecular beam epitaxy (MBE) and the window p*-type layer is PEDOT:PSS formed by the inkjet method. The device exhibits a lifetime of more than 100 d and an APD operation of more than 500 times. We integrated 3-element APD array separated only by a window spot of PEDOT:PSS. The present array device in the APD operation shows no detectable photosignal cross-talk between the neighboring APDs.
Zhifang Li; Yunus E. Erdemli; John L. Volakis; Panos Y. Papalambros
2002-01-01
Previous work in antenna optimization has primarily focused on applications of optimization algorithms in conjunction with problem-specific or semi-analytic tools. However, previous developments in fast algorithms now offer the possibility of designs and moreover allow for full flexibility in material specification across three dimensions. As an example, this paper combines genetic algorithms (GA) and simulated annealing (SA) with fast hybrid
Ali Bahrami; Cihan H. Dagli
1994-01-01
A successful solution to the packing problem is a major step toward material savings on the scrap that could be avoided in the cutting process and therefore money savings. Although the problem is of great interest, no satisfactory algorithm has been found that can be applied to all the possible situations. This paper models a Hybrid Intelligent Packing System (HIPS)
Integrative control strategy of regenerative and hydraulic braking for hybrid electric car
Liang Chu; Wanfeng Sun; Liang Yao; Yongsheng Zhang; Yang Ou; Wenruo Wei; Minghui Liu; Jun Li
2009-01-01
Since electric braking involvement, the braking system of an EV, HEV and FCV becomes much more complex than conventional mechanical alone braking system. The target in this hybrid braking system is to recover the braking energy as much as possible and meanwhile maintain a good braking performance for vehicle safety. For this purpose, the control of this braking system is
Wind power integration in hybrid power system with active energy management
Abdou Tankari Mahamadou; Bailo Camara Mamadou; Dakyo Brayima; Nichita Cristian
2011-01-01
Purpose – The wind speed is very fluctuant and contains a significant energy. Taking into account the turbulent component in the energy management would increase the profitability of the wind-diesel hybrid system. Sometimes, a diesel generator is used to compensate the requested energy but the storage devices are required to prevent disturbances induced by the wind generator current on the
Performance Analysis of Integrated Voice and Data Hybrid-Switched Links
GILBERT F. WILLIAMS; A. Leon-Garcia
1984-01-01
Numerical techniques for the solution of a class of twodimensional Markov processes are presented. These techniques are used to analyze the performance of several versions of hybrid switching including the movable boundary scheme with finite or infinite buffers, with flow control, and with or without TASI. Also included are results for TASI in which the number of off-hook calls is
Hybrid Architecture and Integrated Routing in a Scalable Optical–Wireless Access Network
Wei-Tao Shaw; Shing-Wa Wong; Ning Cheng; Koussalya Balasubramanian; Xiaoqing Zhu; Martin Maier; Leonid G. Kazovsky
2007-01-01
We propose a hybrid optical-wireless access network that consists of reconfigurable optical backhaul and wireless mesh networks (WMNs). The complementary characteristics of wireless and optical networks are combined to provide a broadband and ubiquitous last-mile connection. Wireless mesh routers are deployed to penetrate the vicinity of end users for a flexible and ubiquitous connection. It eliminates massive and geographically scattered
INTEGRATION OF GENETIC AND RADIATION HYBRID MAPS OF THE PIG: THE SECOND GENERATION IMPRH MAPS
Technology Transfer Automated Retrieval System (TEKTRAN)
More than 4500 markers, ESTs and genes have been mapped on IMpRH radiation hybrid panel and submitted to IMpRH Server before 30 March 2002, whereas 757 markers only were mapped on the first generation map (Hawken et al, 1999). To take advantage of the different resolutions observed on the genetic an...
Chakrabortty, S; Sen, M; Pal, P
2014-03-01
A simulation software (ARRPA) has been developed in Microsoft Visual Basic platform for optimization and control of a novel membrane-integrated arsenic separation plant in the backdrop of absence of such software. The user-friendly, menu-driven software is based on a dynamic linearized mathematical model, developed for the hybrid treatment scheme. The model captures the chemical kinetics in the pre-treating chemical reactor and the separation and transport phenomena involved in nanofiltration. The software has been validated through extensive experimental investigations. The agreement between the outputs from computer simulation program and the experimental findings are excellent and consistent under varying operating conditions reflecting high degree of accuracy and reliability of the software. High values of the overall correlation coefficient (R (2)?=?0.989) and Willmott d-index (0.989) are indicators of the capability of the software in analyzing performance of the plant. The software permits pre-analysis, manipulation of input data, helps in optimization and exhibits performance of an integrated plant visually on a graphical platform. Performance analysis of the whole system as well as the individual units is possible using the tool. The software first of its kind in its domain and in the well-known Microsoft Excel environment is likely to be very useful in successful design, optimization and operation of an advanced hybrid treatment plant for removal of arsenic from contaminated groundwater. PMID:24288068
Hou, Chao; Lang, Xing-You; Han, Gao-Feng; Li, Ying-Qi; Zhao, Lei; Wen, Zi; Zhu, Yong-Fu; Zhao, Ming; Li, Jian-Chen; Lian, Jian-She; Jiang, Qing
2013-01-01
Nanoarchitectured electroactive materials can boost rates of Li insertion/extraction, showing genuine potential to increase power output of Li-ion batteries. However, electrodes assembled with low-dimensional nanostructured transition metal oxides by conventional approach suffer from dramatic reductions in energy capacities owing to sluggish ion and electron transport kinetics. Here we report that flexible bulk electrodes, made of three-dimensional bicontinuous nanoporous Cu/MnO2 hybrid and seamlessly integrated with Cu solid current collector, substantially optimizes Li storage behavior of the constituent MnO2. As a result of the unique integration of solid/nanoporous hybrid architecture that simultaneously enhances the electron transport of MnO2, facilitates fast ion diffusion and accommodates large volume changes on Li insertion/extraction of MnO2, the supported MnO2 exhibits a stable capacity of as high as ~1100?mA h g?1 for 1000 cycles, and ultrahigh charge/discharge rates. It makes the environmentally friendly and low-cost electrode as a promising anode for high-performance Li-ion battery applications. PMID:24096928
Richard, Charles; Renaudin, Alan; Aimez, Vincent; Charette, Paul G
2009-05-21
We present a hybrid optical filter design that combines interference and absorbing components for enhanced fluorescence detection in miniaturized highly-integrated lab-on-a-chip devices. The filter is designed in such a way that the advantages of each technology are used to offset the disadvantages of the other. The filter is fabricated with microfabrication compatible processes and materials for monolithic integration with microelectronics and microfluidics devices. The particular embodiment of the filter described herein is designed to discriminate fluorescence emission at 650 nm from excitation at 532 nm. The 9-layer interference filter component is fabricated with alternating TiO(2) and SiO(2) thin-film layers and has an attenuation of -12.6 dB at 532 nm and -0.76 dB at 650 nm. The absorbing filter component is fabricated using a dyed photopolymer (KMPR + Orasol Red) having an attenuation of -32.6 dB at 532 nm and -1.28 dB at 650 nm. The total rejection ratio of the hybrid filter is 43 dB. The filter exhibits very low autofluorescence and performs equally well at off-axis incidence angles. PMID:19417903
Sequential Monte Carlo Methods to Train Neural Network Models
João F. G. De Freitas; Mahesan Niranjan; Andrew H. Gee; Arnaud Doucet
2000-01-01
We discuss a novel strategy for training neural networks using sequential Monte Carlo algorithms and propose a new hybrid gradient descent\\/sampling importance resampling algorithm (HySIR). In terms of computational time and accuracy, the hybrid SIR is a clear improvement over conventional sequential Monte Carlo techniques. The new algorithm may be viewed as a global optimization strategy that allows us to
On Monte Carlo methods for Bayesian inference
Song S. Qian; Craig A. Stow; Mark E. Borsuky
2003-01-01
Bayesian methods are experiencing increased use for probabilistic ecological modelling. Most Bayesian inference requires the numerical approximation of analytically intractable integrals. Two methods based on Monte Carlo simulation have appeared in the ecological\\/environmental modelling literature. Though they sound similar, the Bayesian Monte Carlo (BMC) and Markov Chain Monte Carlo (MCMC) methods are very different in their efficiency and effectiveness in
Integrated optics structures on sol-gel derived organic-inorganic hybrids for optical communications
NASA Astrophysics Data System (ADS)
André, P. S.; Vicente, C. M. S.; Fernandes, V.; Marques, C. A. F.; Pecoraro, E.; Nogueira, R. N.; Wada, N.; Carlos, L. D.; Marques, P. G.; Ferreira, R. A. S.
2011-05-01
Organic-inorganic hybrid materials are a technologically key class of advanced multifunctional materials that fulfil the challenging strict requirements of the beginning of the century: higher levels of sophistication, miniaturisation, recyclability, reliability and low energy consumption with potential to be used as low-cost components in optical networks operating at high bit rates. In this work, high-rejection optical filters (19 dB) first-order Bragg gratings inscribed in channel waveguides written in thin films of sol-gel derived organic-inorganic hybrid based on methacrylic acid modified zirconium tetrapropoxide, Zr(OPrn)4, (so-called di-ureasils), using UV-laser direct-write method.
Hybrid organic crystal/silicon-on-insulator integrated electro-optic modulators
NASA Astrophysics Data System (ADS)
Jazbinsek, Mojca; Hunziker, Christoph; Kwon, Seong-Ji; Figi, Harry; Kwon, O.-Pil; Günter, Peter
2010-02-01
We demonstrate electro-optic modulation in hybrid organic-crystal/silicon photonic waveguides. The organic material is the newly developed organic crystal OH1 with very high electro-optic figures of merit, n3r = 530 pm/V at 1319 nm, and the processing possibilities considerably improved compared to previous high-nonlinearity organic crystals. We have developed an epitaxial-like solution growth of OH1 on various substrates and fabricated electro-optic modulators with electro-optic functionality either directly in OH1 wire waveguides or in OH1 active cladding of silicon wire waveguides. OH1-based waveguides offer a great potential for high-bandwidth, sub-1-V half-wave voltage, hybrid organic/silicon electro-optic modulators with high electro-optic activity and stability.
Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William
2004-06-01
ITS is a powerful and user-friendly software package permitting state of the art Monte Carlo solution of linear time-independent couple electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 5.0, the latest version of ITS, contains (1) improvements to the ITS 3.0 continuous-energy codes, (2)multigroup codes with adjoint transport capabilities, and (3) parallel implementations of all ITS codes. Moreover the general user friendliness of the software has been enhanced through increased internal error checking and improved code portability.
A Hybrid Neural Network Method for UAV Attack Route Integrated Planning
Nan Wang; Xueqiang Gu; Jing Chen; Lincheng Shen; Min Ren
2009-01-01
This paper proposes a hybrid neural network method to solve the UAV attack route planning problem considering multiple factors.\\u000a In this method, the planning procedure is decomposed by two planners: penetration planner and attack planner. The attack planner\\u000a determines a candidate solution set, which adopts Guassian Radial Basis Function Neural Networks (RBFNN) to give a quick performance\\u000a evaluation to find
Fluorescent In Situ Hybridization to Detect Transgene Integration into Plant Genomes
NASA Astrophysics Data System (ADS)
Schwarzacher, Trude
Fluorescent chromosome analysis technologies have advanced our understanding of genome organization during the last 30 years and have enabled the investigation of DNA organization and structure as well as the evolution of chromosomes. Fluorescent chromosome staining allows even small chromosomes to be visualized, characterized by their composition and morphology, and counted. Aneuploidies and polyploidies can be established for species, breeding lines, and individuals, including changes occurring during hybridization or tissue culture and transformation protocols. Fluorescent in situ hybridization correlates molecular information of a DNA sequence with its physical location on chromosomes and genomes. It thus allows determination of the physical position of sequences and often is the only means to determine the abundance and distribution of DNA sequences that are difficult to map with any other molecular method or would require segregation analysis, in particular multicopy or repetitive DNA. Equally, it is often the best way to establish the incorporation of transgenes, their numbers, and physical organization along chromosomes. This chapter presents protocols for probe and chromosome preparation, fluorescent in situ hybridization, chromosome staining, and the analysis of results.
NASA Technical Reports Server (NTRS)
Richardson, Erin; Hays, M. J.; Blackwood, J. M.; Skinner, T.
2014-01-01
The Liquid Propellant Fragment Overpressure Acceleration Model (L-FOAM) is a tool developed by Bangham Engineering Incorporated (BEi) that produces a representative debris cloud from an exploding liquid-propellant launch vehicle. Here it is applied to the Core Stage (CS) of the National Aeronautics and Space Administration (NASA) Space Launch System (SLS launch vehicle). A combination of Probability Density Functions (PDF) based on empirical data from rocket accidents and applicable tests, as well as SLS specific geometry are combined in a MATLAB script to create unique fragment catalogues each time L-FOAM is run-tailored for a Monte Carlo approach for risk analysis. By accelerating the debris catalogue with the BEi blast model for liquid hydrogen / liquid oxygen explosions, the result is a fully integrated code that models the destruction of the CS at a given point in its trajectory and generates hundreds of individual fragment catalogues with initial imparted velocities. The BEi blast model provides the blast size (radius) and strength (overpressure) as probabilities based on empirical data and anchored with analytical work. The coupling of the L-FOAM catalogue with the BEi blast model is validated with a simulation of the Project PYRO S-IV destruct test. When running a Monte Carlo simulation, L-FOAM can accelerate all catalogues with the same blast (mean blast, 2 s blast, etc.), or vary the blast size and strength based on their respective probabilities. L-FOAM then propagates these fragments until impact with the earth. Results from L-FOAM include a description of each fragment (dimensions, weight, ballistic coefficient, type and initial location on the rocket), imparted velocity from the blast, and impact data depending on user desired application. LFOAM application is for both near-field (fragment impact to escaping crew capsule) and far-field (fragment ground impact footprint) safety considerations. The user is thus able to use statistics from a Monte Carlo set of L-FOAM catalogues to quantify risk for a multitude of potential CS destruct scenarios. Examples include the effect of warning time on the survivability of an escaping crew capsule or the maximum fragment velocities generated by the ignition of leaking propellants in internal cavities.
Method for producing a hybridization of detector array and integrated circuit for readout
NASA Technical Reports Server (NTRS)
Fossum, Eric R. (inventor); Grunthaner, Frank J. (inventor)
1993-01-01
A process is explained for fabricating a detector array in a layer of semiconductor material on one substrate and an integrated readout circuit in a layer of semiconductor material on a separate substrate in order to select semiconductor material for optimum performance of each structure, such as GaAs for the detector array and Si for the integrated readout circuit. The detector array layer is lifted off its substrate, laminated on the metallized surface on the integrated surface, etched with reticulating channels to the surface of the integrated circuit, and provided with interconnections between the detector array pixels and the integrated readout circuit through the channels. The adhesive material for the lamination is selected to be chemically stable to provide electrical and thermal insulation and to provide stress release between the two structures fabricated in semiconductor materials that may have different coefficients of thermal expansion.
NASA Astrophysics Data System (ADS)
Bauer, J.; Sommerer, F.; Mairani, A.; Unholtz, D.; Farook, R.; Handrack, J.; Frey, K.; Marcelos, T.; Tessonnier, T.; Ecker, S.; Ackermann, B.; Ellerbrock, M.; Debus, J.; Parodi, K.
2014-08-01
Monte Carlo (MC) simulations of beam interaction and transport in matter are increasingly considered as essential tools to support several aspects of radiation therapy. Despite the vast application of MC to photon therapy and scattered proton therapy, clinical experience in scanned ion beam therapy is still scarce. This is especially the case for ions heavier than protons, which pose additional issues like nuclear fragmentation and varying biological effectiveness. In this work, we present the evaluation of a dedicated framework which has been developed at the Heidelberg Ion Beam Therapy Center to provide automated FLUKA MC simulations of clinical patient treatments with scanned proton and carbon ion beams. Investigations on the number of transported primaries and the dimension of the geometry and scoring grids have been performed for a representative class of patient cases in order to provide recommendations on the simulation settings, showing that recommendations derived from the experience in proton therapy cannot be directly translated to the case of carbon ion beams. The MC results with the optimized settings have been compared to the calculations of the analytical treatment planning system (TPS), showing that regardless of the consistency of the two systems (in terms of beam model in water and range calculation in different materials) relevant differences can be found in dosimetric quantities and range, especially in the case of heterogeneous and deep seated treatment sites depending on the ion beam species and energies, homogeneity of the traversed tissue and size of the treated volume. The analysis of typical TPS speed-up approximations highlighted effects which deserve accurate treatment, in contrast to adequate beam model simplifications for scanned ion beam therapy. In terms of biological dose calculations, the investigation of the mixed field components in realistic anatomical situations confirmed the findings of previous groups so far reported only in homogenous water targets. This work can thus be useful to other centers commencing clinical experience in scanned ion beam therapy.
Arora, Bhavna; Mohanty, Binayak P; McGuire, Jennifer T
2015-04-15
Predicting and controlling the concentrations of redox-sensitive elements are primary concerns for environmental remediation of contaminated sites. These predictions are complicated by dynamic flow processes as hydrologic variability is a governing control on conservative and reactive chemical concentrations. Subsurface heterogeneity in the form of layers and lenses further complicates the flow dynamics of the system impacting chemical concentrations including redox-sensitive elements. In response to these complexities, this study investigates the role of heterogeneity and hydrologic processes in an effective parameter upscaling scheme from the column to the landfill scale. We used a Markov chain Monte Carlo (MCMC) algorithm to derive upscaling coefficients for hydrological and geochemical parameters, which were tested for variations across heterogeneous systems (layers and lenses) and interaction of flow processes based on the output uncertainty of dominant biogeochemical concentrations at the Norman Landfill site, a closed municipal landfill with prevalent organic and trace metal contamination. The results from MCMC analysis indicated that geochemical upscaling coefficients based on effective concentration ratios incorporating local heterogeneity across layered and lensed systems produced better estimates of redox-sensitive biogeochemistry at the field scale. MCMC analysis also suggested that inclusion of hydrological parameters in the upscaling scheme reduced the output uncertainty of effective mean geochemical concentrations by orders of magnitude at the Norman Landfill site. This was further confirmed by posterior density plots of the scaling coefficients that revealed unimodal characteristics when only geochemical processes were involved, but produced multimodal distributions when hydrological parameters were included. The multimodality again suggests the effect of heterogeneity and lithologic variability on the distribution of redox-sensitive elements at the Norman Landfill site. PMID:25644839
Bauer, J; Sommerer, F; Mairani, A; Unholtz, D; Farook, R; Handrack, J; Frey, K; Marcelos, T; Tessonnier, T; Ecker, S; Ackermann, B; Ellerbrock, M; Debus, J; Parodi, K
2014-08-21
Monte Carlo (MC) simulations of beam interaction and transport in matter are increasingly considered as essential tools to support several aspects of radiation therapy. Despite the vast application of MC to photon therapy and scattered proton therapy, clinical experience in scanned ion beam therapy is still scarce. This is especially the case for ions heavier than protons, which pose additional issues like nuclear fragmentation and varying biological effectiveness. In this work, we present the evaluation of a dedicated framework which has been developed at the Heidelberg Ion Beam Therapy Center to provide automated FLUKA MC simulations of clinical patient treatments with scanned proton and carbon ion beams. Investigations on the number of transported primaries and the dimension of the geometry and scoring grids have been performed for a representative class of patient cases in order to provide recommendations on the simulation settings, showing that recommendations derived from the experience in proton therapy cannot be directly translated to the case of carbon ion beams. The MC results with the optimized settings have been compared to the calculations of the analytical treatment planning system (TPS), showing that regardless of the consistency of the two systems (in terms of beam model in water and range calculation in different materials) relevant differences can be found in dosimetric quantities and range, especially in the case of heterogeneous and deep seated treatment sites depending on the ion beam species and energies, homogeneity of the traversed tissue and size of the treated volume. The analysis of typical TPS speed-up approximations highlighted effects which deserve accurate treatment, in contrast to adequate beam model simplifications for scanned ion beam therapy. In terms of biological dose calculations, the investigation of the mixed field components in realistic anatomical situations confirmed the findings of previous groups so far reported only in homogenous water targets. This work can thus be useful to other centers commencing clinical experience in scanned ion beam therapy. PMID:25079387
NASA Astrophysics Data System (ADS)
Symeonidis, Vasileios; Karniadakis, George Em
2006-10-01
We propose new schemes for integrating the stochastic differential equations of dissipative particle dynamics (DPD) in simulations of dilute polymer solutions. The hybrid DPD models consist of hard potentials that describe the microscopic dynamics of polymers and soft potentials that describe the mesoscopic dynamics of the solvent. In particular, we develop extensions to the velocity-Verlet and Lowe's approaches - two representative DPD time-integrators - following a subcycling procedure whereby the solvent is advanced with a timestep much larger than the one employed in the polymer time-integration. The introduction of relaxation parameters allows optimization studies for accuracy while maintaining the low computational complexity of standard DPD algorithms. We demonstrate through equilibrium simulations that a 10-fold gain in efficiency can be obtained with the time-staggered algorithms without loss of accuracy compared to the non-staggered schemes. We then apply the new approach to investigate the scaling response of polymers in equilibrium as well as the dynamics of ?-phage DNA molecules subjected to shear.
Symeonidis, Vasileios [Division of Applied Mathematics, Brown University, 182 George Street, Box F, Providence, RI 02912 (United States); Karniadakis, George Em [Division of Applied Mathematics, Brown University, 182 George Street, Box F, Providence, RI 02912 (United States)]. E-mail: gk@dam.brown.edu
2006-10-10
We propose new schemes for integrating the stochastic differential equations of dissipative particle dynamics (DPD) in simulations of dilute polymer solutions. The hybrid DPD models consist of hard potentials that describe the microscopic dynamics of polymers and soft potentials that describe the mesoscopic dynamics of the solvent. In particular, we develop extensions to the velocity-Verlet and Lowe's approaches - two representative DPD time-integrators - following a subcycling procedure whereby the solvent is advanced with a timestep much larger than the one employed in the polymer time-integration. The introduction of relaxation parameters allows optimization studies for accuracy while maintaining the low computational complexity of standard DPD algorithms. We demonstrate through equilibrium simulations that a 10-fold gain in efficiency can be obtained with the time-staggered algorithms without loss of accuracy compared to the non-staggered schemes. We then apply the new approach to investigate the scaling response of polymers in equilibrium as well as the dynamics of {lambda}-phage DNA molecules subjected to shear.
Li, Liang; Chen, Zhiqiang; Cong, Wenxiang; Wang, Ge
2015-03-01
Spectral CT with photon counting detectors can significantly improve CT performance by reducing image noise and dose, increasing contrast resolution and material specificity, as well as enabling functional and molecular imaging with existing and emerging probes. However, the current photon counting detector architecture is difficult to balance the number of energy bins and the statistical noise in each energy bin. Moreover, the hardware support for multi-energy bins demands a complex circuit which is expensive. In this paper, we promote a new scheme known as hybrid detectors that combine the dynamic-threshold-based counting and integrating modes. In this scheme, an energy threshold can be dynamically changed during a spectral CT scan, which can be considered as compressive sensing along the spectral dimension. By doing so, the number of energy bins can be retrospectively specified, even in a spatially varying fashion. To establish the feasibility and merits of such hybrid detectors, we develop a tensor-based PRISM algorithm to reconstruct a spectral CT image from dynamic dual-energy data, and perform experiments with simulated and real data, producing very promising results. PMID:25252279
NASA Astrophysics Data System (ADS)
Patil, Avinash J.; Li, Mei; Mann, Stephen
2013-07-01
Synthesis of functional hybrid nanoscale objects has been a core focus of the rapidly progressing field of nanomaterials science. In particular, there has been significant interest in the integration of evolutionally optimized biological systems such as proteins, DNA, virus particles and cells with functional inorganic building blocks to construct mesoscopic architectures and nanostructured materials. However, in many cases the fragile nature of the biomolecules seriously constrains their potential applications. As a consequence, there is an on-going quest for the development of novel strategies to modulate the thermal and chemical stabilities, and performance of biomolecules under adverse conditions. This feature article highlights new methods of ``inorganic molecular wrapping'' of single or multiple protein molecules, individual double-stranded DNA helices, lipid bilayer vesicles and self-assembled organic dye superstructures using inorganic building blocks to produce bio-inorganic nanoconstructs with core-shell type structures. We show that spatial isolation of the functional biological nanostructures as ``armour-plated'' enzyme molecules or polynucleotide strands not only maintains their intact structure and biochemical properties, but also enables the fabrication of novel hybrid nanomaterials for potential applications in diverse areas of bionanotechnology.
NASA Astrophysics Data System (ADS)
Yusof, Fadhilah; Kane, Ibrahim Lawal; Yusop, Zulkifli
2015-02-01
Precarious circumstances related to rainfall events can be due to very intense or persistence of rainfall over a long period of time. Such events may give rise to an exceedence of the capacity of sewer systems resulting to landslides or flooding. One of the conventional ways of measuring such risk associated with persistence in rain is done through studies of long term persistence and volatility persistence. This work investigates the persistence level of Kuantan daily rainfall using the hybrid of autoregressive fractional integrated moving average (ARFIMA) and hidden Markov model (HMM). The result shows that the rainfall variability period returns quickly to its usual variability level which may not have a lasting period of extreme wet, hence relatively stable rainfall behavior is observed in Kuantan rainfall. This will enhance the understanding of the process for the successful development and implementation of water resource tools to assess engineering and environmental problems such as flood control.
HORIZONTAL HYBRID SOLAR LIGHT PIPE: AN INTEGRATED SYSTEM OF DAYLIGHT AND ELECTRIC LIGHT
This project will test the feasibility of an advanced energy efficient perimeter lighting system that integrates daylighting, electric lighting, and lighting controls to reduce electricity consumption. The system is designed to provide adequate illuminance levels in deep-floor...
Electronic integration of fuel cell and battery system in novel hybrid vehicle
NASA Astrophysics Data System (ADS)
Fisher, Peter; Jostins, John; Hilmansen, Stuart; Kendall, Kevin
2012-12-01
The objective of this work was to integrate a lithium ion battery pack, together with its management system, into a hydrogen fuel cell drive train contained in a lightweight city car. Electronic units were designed to link the drive train components using conventional circuitry. These were built, tested and shown to perform according to the design. These circuits allowed start-up of battery management system, motor controller, fuel cell warm-up and torque monitoring. After assembling the fuel cell and battery in the vehicle, full system tests were performed. Analysis of results from vehicle demonstrations showed operation was satisfactory. The conclusion was that the electronic integration was successful, but the design needed optimisation and fine tuning. Eight vehicles were then fitted with the electronically integrated fuel cell-battery power pack. Trials were then started to test the integration more fully, with a duration of 12 months from 2011 to 2012 in the CABLED project.
New integration scheme of GPS-INS hybrid navigation system for maneuvering spacecraft
NASA Astrophysics Data System (ADS)
Tanabe, T.; Harigae, M.; Koyama, H.
Integration schemes of the GPS with INS are considered. In the conventional navigation scheme, information from INS is usually used in the form of velocity-aiding signal to the receiver-tracking loops. In this paper, a new integration scheme is proposed which performs more effective information exchange so that it is more tolerant to RF interferences and unmodeled INS errors than the conventional scheme. These results are obtained from theoretical analyses and confirmed by computer simulations including GPS receiver dynamics.
Zhihao Li; Alireza Khaligh
2009-01-01
Decreasing world oil and gas resources as well as environmental concerns have driven automotive industry to develop more efficient and cleaner vehicles to reduce fuel consumption and protect the environment. The hybrid vehicle technology offers a reasonable solution for the challenges of energy and environment. Renewable energies, such as solar and wind energy can also be integrated with the structure
Monte Carlo sampling from the quantum state space. II
NASA Astrophysics Data System (ADS)
Seah, Yi-Lin; Shang, Jiangwei; Khoon Ng, Hui; Nott, David John; Englert, Berthold-Georg
2015-04-01
High-quality random samples of quantum states are needed for a variety of tasks in quantum information and quantum computation. Searching the high-dimensional quantum state space for a global maximum of an objective function with many local maxima or evaluating an integral over a region in the quantum state space are but two exemplary applications of many. These tasks can only be performed reliably and efficiently with Monte Carlo methods, which involve good samplings of the parameter space in accordance with the relevant target distribution. We show how the Markov-chain Monte Carlo method known as Hamiltonian Monte Carlo, or hybrid Monte Carlo, can be adapted to this context. It is applicable when an efficient parameterization of the state space is available. The resulting random walk is entirely inside the physical parameter space, and the Hamiltonian dynamics enable us to take big steps, thereby avoiding strong correlations between successive sample points while enjoying a high acceptance rate. We use examples of single and double qubit measurements for illustration.
Monte Carlo sampling from the quantum state space. II
Yi-Lin Seah; Jiangwei Shang; Hui Khoon Ng; David John Nott; Berthold-Georg Englert
2014-10-02
High-quality random samples of quantum states are needed for a variety of tasks in quantum information and quantum computation. Searching the high-dimensional quantum state space for a global maximum of an objective function with many local maxima or evaluating an integral over a region in the quantum state space are but two exemplary applications of many. These tasks can only be performed reliably and efficiently with Monte Carlo methods, which involve good samplings of the parameter space in accordance with the relevant target distribution. We show how the Markov-chain Monte Carlo method known as Hamiltonian Monte Carlo, or Hybrid Monte Carlo, can be adapted to this context. It is applicable when an efficient parameterization of the state space is available. The resulting random walk is entirely inside the physical parameter space, and the Hamiltonian dynamics enable us to take big steps, thereby avoiding strong correlations between successive sample points while enjoying a high acceptance rate. We use examples of single and double qubit measurements for illustration.
Winkel, Abigail Ford; Gillespie, Colleen; Hiruma, Marissa T.; Goepfert, Alice R.; Zabar, Sondra; Szyld, Demian
2014-01-01
Background Assessment of obstetrics-gynecology residents' ability to integrate clinical judgment, interpersonal skills, and technical ability in a uniform fashion is required to document achievement of benchmarks of competency. An observed structured clinical examination that incorporates simulation and bench models uses direct observation of performance to generate formative feedback and standardized evaluation. Methods The Test of Integrated Professional Skills (TIPS) is a 5-station performance-based assessment that uses standardized patients and complex scenarios involving ultrasonography, procedural skills, and evidence-based medicine. Standardized patients and faculty rated residents by using behaviorally anchored checklists. Mean scores reflecting performance in TIPS were compared across competency domains and by developmental level (using analysis of variance) and then compared to standard faculty clinical evaluations (using Spearman ?). Participating faculty and residents were also asked to evaluate the usefulness of the TIPS. Results Twenty-four residents participated in the TIPS. Checklist items used to assess competency were sufficiently reliable, with Cronbach ? estimates from 0.69 to 0.82. Performance improved with level of training, with wide variation in performance. Standard faculty evaluations did not correlate with TIPS performance. Several residents who were rated as average or above average by faculty performed poorly on the TIPS (> 1 SD below the mean). Both faculty and residents found the TIPS format useful, providing meaningful evaluation and opportunity for feedback. Conclusions A simulation-based observed structured clinical examination facilitates observation of a range of skills, including competencies that are difficult to observe and measure in a standardized way. Debriefing with faculty provides an important interface for identification of performance gaps and individualization of learning plans. PMID:24701321
Chiang, C C; Kennell, J C; Wanner, L A; Lambowitz, A M
1994-01-01
The Mauriceville and Varkud mitochondrial plasmids of Neurospora spp. are closely related, small circular DNAs that propagate via an RNA intermediate and reverse transcription. Although the plasmids ordinarily replicate autonomously, they can also integrate into mitochondrial DNA (mtDNA), yielding defective mtDNAs that in some cases cause senescence. To investigate the integration mechanism, we analyzed four cases in which the Varkud plasmid integrated into the mitochondrial small rRNA gene, three in wild-type subcultures and one in a senescent mutant. Our analysis suggests that the integrations occurred by the plasmid reverse transcriptase template switching between the plasmid transcript and internal sequences in the mitochondrial small rRNA to yield hybrid cDNAs that circularized and recombined homologously with the mtDNA. The integrated plasmid sequences are transcribed, presumably from the mitochondrial small rRNA promoters, resulting in hybrid RNAs containing the 5' segment of the mitochondrial small rRNA linked head-to-tail to the full-length plasmid transcript. Analysis of additional senescent mutants revealed three cases in which the plasmid used the same mechanism to integrate at other locations in the mtDNA. In these cases, circular variant plasmids that had incorporated a mitochondrial tRNA or tRNA-like sequence by template switching integrated by homologous recombination at the site of the corresponding tRNA or tRNA-like sequence in mtDNA. This simple integration mechanism involving template switching to generate a hybrid cDNA that integrates homologously could have been used by primitive retroelements prior to the acquisition of a specialized integration machinery. Images PMID:7523850
A hybrid approach for integrated healthcare cooperative purchasing and supply chain configuration.
Rego, Nazaré; Claro, João; Pinho de Sousa, Jorge
2014-12-01
This paper presents an innovative and flexible approach for recommending the number, size and composition of purchasing groups, for a set of hospitals willing to cooperate, while minimising their shared supply chain costs. This approach makes the financial impact of the various cooperation alternatives transparent to the group and the individual participants, opening way to a negotiation process concerning the allocation of the cooperation costs and gains. The approach was developed around a hybrid Variable Neighbourhood Search (VNS)/Tabu Search metaheuristic, resulting in a flexible tool that can be applied to purchasing groups with different characteristics, namely different operative and market circumstances, and to supply chains with different topologies and atypical cost characteristics. Preliminary computational results show the potential of the approach in solving a broad range of problems. PMID:24370921
Hybrid classical integrable structure of squashed sigma models -- a short summary
Io Kawaguchi; Kentaroh Yoshida
2011-10-31
We give a short summary of our recent works on the classical integrable structure of two-dimensional non-linear sigma models defined on squashed three-dimensional spheres. There are two descriptions to describe the classical dynamics, 1) the rational description and 2) the trigonometric description. It is possible to construct two different types of Lax pairs depending on the descriptions, and the classical integrability is shown by computing classical r/s-matrices satisfying the extended Yang-Baxter equation in both descriptions. In the former the system is described as an integrable system of rational type. On the other hand, in the latter it is described as trigonometric type. There exists a non-local map between the two descriptions and those are equivalent. This is a non-local generalization of the left-right duality in principal chiral models.
Clark, M. A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); Joo, Balint [Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States); Kennedy, A. D. [Tait Institute and SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, Scotland (United Kingdom); Silva, P. J. [Centro de Fisica Computacional, Universidade de Coimbra (Portugal)
2011-10-01
We show how the integrators used for the molecular dynamics step of the Hybrid Monte Carlo algorithm can be further improved. These integrators not only approximately conserve some Hamiltonian H but conserve exactly a nearby shadow Hamiltonian H-tilde. This property allows for a new tuning method of the molecular dynamics integrator and also allows for a new class of integrators (force-gradient integrators) which is expected to reduce significantly the computational cost of future large-scale gauge field ensemble generation.
Honda, Norihiro; Ishii, Katsunori; Terada, Takaya; Nanjo, Takuya; Awazu, Kunio
2011-05-01
Photodynamic therapy (PDT) efficacy depends on the amount of light distribution within the tissue. However, conventional PDT does not consider the laser irradiation dose during PDT. The optical properties of biological tissues (absorption coefficient ?(a), reduced scattering coefficient ?'s), anisotropy factor g, refractive index, etc.) help us to recognize light propagation through the tissue. The goal of this paper is to acquire the knowledge of the light propagation within tissue during and after PDT with the optical property of PDT-performed mouse tumor tissue. The optical properties of mouse tumor tissues were evaluated using a double integrating sphere setup and the algorithm based on the inverse Monte Carlo method in the wavelength range from 350 to 1000 nm. During PDT, the ?(a) and ?'s were not changed after 1 and 5 min of irradiation. After PDT, the ?'s in the wavelength range from 600 to 1000 nm increased with the passage of time. For seven days after PDT, the ?'s increased by 1.7 to 2.0 times, which results in the optical penetration depth decreased by 1.4 to 1.8 times. To ensure an effective procedure, the adjustment of laser parameters for the decreasing penetration depth is recommended for the re-irradiation of PDT. PMID:21639587
ERIC Educational Resources Information Center
Kamruzzaman, M.
2014-01-01
This study reports an action research undertaken at Queensland University of Technology. It evaluates the effectiveness of the integration of geographic information systems (GIS) within the substantive domains of an existing land use planning course in 2011. Using student performance, learning experience survey, and questionnaire survey data, it…
Breen, Matthew; Jouquand, Sophie; Renier, Corinne; Mellersh, Cathryn S.; Hitte, Christophe; Holmes, Nigel G.; Chéron, Angélique; Suter, Nicola; Vignaux, Françoise; Bristow, Anna E.; Priat, Catherine; McCann, E.; André, Catherine; Boundy, Sam; Gitsham, Paul; Thomas, Rachael; Bridge, Wendy L.; Spriggs, Helen F.; Ryder, Ed J.; Curson, Alistair; Sampson, Jeff; Ostrander, Elaine A.; Binns, Matthew M.; Galibert, Francis
2001-01-01
We present here the first fully integrated, comprehensive map of the canine genome, incorporating detailed cytogenetic, radiation hybrid (RH), and meiotic information. We have mapped a collection of 266 chromosome-specific cosmid clones, each containing a microsatellite marker, to all 38 canine autosomes by fluorescence in situ hybridization (FISH). A 1500-marker RH map, comprising 1078 microsatellites, 320 dog gene markers, and 102 chromosome-specific markers, has been constructed using the RHDF5000-2 whole-genome radiation hybrid panel. Meiotic linkage analysis was performed, with at least one microsatellite marker from each dog autosome on a panel of reference families, allowing one meiotic linkage group to be anchored to all 38 dog autosomes. We present a karyotype in which each chromosome is identified by one meiotic linkage group and one or more RH groups. This updated integrated map, containing a total of 1800 markers, covers >90% of the dog genome. Positional selection of anchor clones enabled us, for the first time, to orientate nearly all of the integrated groups on each chromosome and to evaluate the extent of individual chromosome coverage in the integrated genome map. Finally, the inclusion of 320 dog genes into this integrated map enhances existing comparative mapping data between human and dog, and the 1000 mapped microsatellite markers constitute an invaluable tool with which to perform genome scanning studies on pedigrees of interest. PMID:11591656
Quantum Gibbs ensemble Monte Carlo
Fantoni, Riccardo, E-mail: rfantoni@ts.infn.it [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Calle Larga S. Marta DD2137, I-30123 Venezia (Italy); Moroni, Saverio, E-mail: moroni@democritos.it [DEMOCRITOS National Simulation Center, Istituto Officina dei Materiali del CNR and SISSA Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, I-34136 Trieste (Italy)
2014-09-21
We present a path integral Monte Carlo method which is the full quantum analogue of the Gibbs ensemble Monte Carlo method of Panagiotopoulos to study the gas-liquid coexistence line of a classical fluid. Unlike previous extensions of Gibbs ensemble Monte Carlo to include quantum effects, our scheme is viable even for systems with strong quantum delocalization in the degenerate regime of temperature. This is demonstrated by an illustrative application to the gas-superfluid transition of {sup 4}He in two dimensions.
NASA Astrophysics Data System (ADS)
Saljoghei, Arsalan; Browning, Colm; Smyth, Frank; Barry, Liam P.
2015-03-01
In this paper the transmission of OFDM based wired/wireless services for hybrid PONs using direct laser modulation is studied. To overcome the limitations imposed by direct modulation of cost effective low bandwidth laser transmitters, we make use of novel monolithically integrated Discrete Mode lasers and optical injection. The system includes a wired OFDM signal, operating at 12.5 Gb/s and three wireless signals delivering Long Term Evolution (LTE) services encoded with 16 QAM. The system's performance is evaluated for various relative power ratios of the wired/wireless signals. Additionally, the impact of Relative Intensity Noise (RIN) on such a hybrid system is studied through computer simulations.
John J. Mahmarian
2007-01-01
A natural extension of current imaging paradigms for diagnosing coronary artery disease may well be the integration of CT\\u000a with myocardial perfusion single-photon CT (SPECT). Although there is a wealth of clinical information regarding the utility\\u000a of SPECT, the value of CT in the cardiology arena has only recently been explored. CT has the advantage of detecting coronary\\u000a atherosclerosis at
Fazal U. Syed; Ming L. Kuang; Matt Smith; Shunsuke Okubo; Hao Ying
2009-01-01
With the increased emphasis on improving fuel economy and reducing emissions, hybrid electric vehicles (HEVs) have emerged as very strong candidates to achieve these goals. The power-split hybrid system, which is a complex hybrid powertrain, exhibits great potential to improve fuel economy by determining the most efficient regions for engine operation and thereby high-voltage (HV) battery operation to achieve overall
Integrated thermal and energy management of plug-in hybrid electric vehicles
NASA Astrophysics Data System (ADS)
Shams-Zahraei, Mojtaba; Kouzani, Abbas Z.; Kutter, Steffen; Bäker, Bernard
2012-10-01
In plug-in hybrid electric vehicles (PHEVs), the engine temperature declines due to reduced engine load and extended engine off period. It is proven that the engine efficiency and emissions depend on the engine temperature. Also, temperature influences the vehicle air-conditioner and the cabin heater loads. Particularly, while the engine is cold, the power demand of the cabin heater needs to be provided by the batteries instead of the waste heat of engine coolant. The existing energy management strategies (EMS) of PHEVs focus on the improvement of fuel efficiency based on hot engine characteristics neglecting the effect of temperature on the engine performance and the vehicle power demand. This paper presents a new EMS incorporating an engine thermal management method which derives the global optimal battery charge depletion trajectories. A dynamic programming-based algorithm is developed to enforce the charge depletion boundaries, while optimizing a fuel consumption cost function by controlling the engine power. The optimal control problem formulates the cost function based on two state variables: battery charge and engine internal temperature. Simulation results demonstrate that temperature and the cabin heater/air-conditioner power demand can significantly influence the optimal solution for the EMS, and accordingly fuel efficiency and emissions of PHEVs.
Fischer, J
2005-12-21
This report summarizes the results of a field verification pilot site investigation that involved the installation of a hybrid integrated active desiccant/vapor-compression rooftop heating, ventilation, and air-conditioning (HVAC) unit at an elementary school in the Atlanta Georgia area. For years, the school had experienced serious humidity and indoor air quality (IAQ) problems that had resulted in occupant complaints and microbial (mold) remediation. The outdoor air louvers of the original HVAC units had been closed in an attempt to improve humidity control within the space. The existing vapor compression variable air volume system was replaced by the integrated active desiccant rooftop (IADR) system that was described in detail in an Oak Ridge National Laboratory (ORNL) report published in 2004 (Fischer and Sand 2004). The IADR system and all space conditions have been monitored remotely for more than a year. The hybrid system was able to maintain both the space temperature and humidity as desired while delivering the outdoor air ventilation rate required by American Society of Heating, Refrigerating and Air-Conditioning Engineers Standard 62. The performance level of the IADR unit and the overall system energy efficiency was measured and found to be very high. A comprehensive IAQ investigation was completed by the Georgia Tech Research Institute before and after the system retrofit. Before-and-after data resulting from this investigation confirmed a significant improvement in IAQ, humidity control, and occupant comfort. These observations were reported by building occupants and are echoed in a letter to ORNL from the school district energy manager. The IADR system was easily retrofitted in place of the original rooftop system using a custom curb adapter. All work was completed in-house by the school's maintenance staff over one weekend. A subsequent cost analysis completed for the school district by the design engineer of record concluded that the IADR system being investigated was actually less expensive to install than other less-efficient options, most of which were unable to deliver the required ventilation while maintaining the desired space humidity levels.
Hybrid information privacy system: integration of chaotic neural network and RSA coding
NASA Astrophysics Data System (ADS)
Hsu, Ming-Kai; Willey, Jeff; Lee, Ting N.; Szu, Harold H.
2005-03-01
Electronic mails are adopted worldwide; most are easily hacked by hackers. In this paper, we purposed a free, fast and convenient hybrid privacy system to protect email communication. The privacy system is implemented by combining private security RSA algorithm with specific chaos neural network encryption process. The receiver can decrypt received email as long as it can reproduce the specified chaos neural network series, so called spatial-temporal keys. The chaotic typing and initial seed value of chaos neural network series, encrypted by the RSA algorithm, can reproduce spatial-temporal keys. The encrypted chaotic typing and initial seed value are hidden in watermark mixed nonlinearly with message media, wrapped with convolution error correction codes for wireless 3rd generation cellular phones. The message media can be an arbitrary image. The pattern noise has to be considered during transmission and it could affect/change the spatial-temporal keys. Since any change/modification on chaotic typing or initial seed value of chaos neural network series is not acceptable, the RSA codec system must be robust and fault-tolerant via wireless channel. The robust and fault-tolerant properties of chaos neural networks (CNN) were proved by a field theory of Associative Memory by Szu in 1997. The 1-D chaos generating nodes from the logistic map having arbitrarily negative slope a = p/q generating the N-shaped sigmoid was given first by Szu in 1992. In this paper, we simulated the robust and fault-tolerance properties of CNN under additive noise and pattern noise. We also implement a private version of RSA coding and chaos encryption process on messages.
Navarro, Julio A
1990-01-01
-Controlled Oscillators and Switchable 8z Tunable CPW-Slotline Filters. (December 1990) Julio Angel Navarro, B. S. , Texas ASM University Chair of Advisory Committee: Dr. Kai Chang A Gunn device has been integrated with a notch antenna to create a bias tuned active... with a notch antenna to create a varactor-tuned active antenna. This circuit uses a smooth-tapered notch antenna and a slotline-CPW resonator. The design maintains the Gunn bias voltage constant and uses the var- actor for frequency tuning to achieve a...
NASA Astrophysics Data System (ADS)
Yang, Wei; Hall, Trevor J.
2013-12-01
The Internet is entering an era of cloud computing to provide more cost effective, eco-friendly and reliable services to consumer and business users. As a consequence, the nature of the Internet traffic has been fundamentally transformed from a pure packet-based pattern to today's predominantly flow-based pattern. Cloud computing has also brought about an unprecedented growth in the Internet traffic. In this paper, a hybrid optical switch architecture is presented to deal with the flow-based Internet traffic, aiming to offer flexible and intelligent bandwidth on demand to improve fiber capacity utilization. The hybrid optical switch is capable of integrating IP into optical networks for cloud-based traffic with predictable performance, for which the delay performance of the electronic module in the hybrid optical switch architecture is evaluated through simulation.
NASA Astrophysics Data System (ADS)
Böhm, Michael C.; Schulte, Joachim; Utrera, Luis
Feynman path-integral quantum Monte Carlo (QMC) simulations and an analytic many-body approach are used to study the ground state properties of one-dimensional (1D) chains in the theoretical framework of model Hamiltonians of the Hubbard type. The QMC algorithm is employed to derive position-space quantities, while band structure properties are evaluated by combining QMC data with expressions derived in momentum (k) space. Bridging link between both representations is the quasi-chemical approximation (QCA). Electronic charge fluctuations <(?n2i)> and the fluctuations of the magnetic local moments <(?s2i)> are studied as a function of the on-site density
NASA Astrophysics Data System (ADS)
Lindsay, Anthony; McCloskey, John; Simão, Nuno; Murphy, Shane; Bhloscaidh, Mairead Nic
2014-05-01
Identifying fault sections where slip deficits have accumulated may provide a means for understanding sequences of large megathrust earthquakes. Stress accumulated during the interseismic period on an active megathrust is stored as potential slip, referred to as slip deficit, along locked sections of the fault. Analysis of the spatial distribution of slip during antecedent events along the fault will show where the locked plate has spent its stored slip. Areas of unreleased slip indicate where the potential for large events remain. The location of recent earthquakes and their distribution of slip can be estimated from instrumentally recorded seismic and geodetic data. However, long-term slip-deficit modelling requires detailed information on the size and distribution of slip for pre-instrumental events over hundreds of years covering more than one 'seismic cycle'. This requires the exploitation of proxy sources of data. Coral microatolls, growing in the intertidal zone of the outer island arc of the Sunda trench, present the possibility of reconstructing slip for a number of pre-instrumental earthquakes. Their growth is influenced by tectonic flexing of the continental plate beneath them; they act as long term recorders of the vertical component of deformation. However, the sparse distribution of data available using coral geodesy results in a under determined problem with non-unique solutions. Rather than accepting any one realisation as the definite model satisfying the coral displacement data, a Monte Carlo approach identifies a suite of models consistent with the observations. Using a Genetic Algorithm to accelerate the identification of desirable models, we have developed a Monte Carlo Slip Estimator- Genetic Algorithm (MCSE-GA) which exploits the full range of uncertainty associated with the displacements. Each iteration of the MCSE-GA samples different values from within the spread of uncertainties associated with each coral displacement. The Genetic Algorithm element of the MCSE-GA allows it to recombine the information stored in a population of randomly generated models to rapidly converge on a possible solution. These solutions are evaluated and those satisfying a threshold number of observations join an ensemble of models contributing to a final Weighted Average Model (WAM). The WAM represents a high resolution estimate of the slip distribution responsible for any given set of displacements. Analysis of the slip values of the ensemble models allows areas of high confidence to be identified where the standard deviation is low. Similarly, areas of low confidence will be found where standard deviations are high. This presentation will demonstrate the ability of the MCSE-GA to produce both accurate models of slip for a number of recent instrumentally recorded earthquakes along the Sunda Trench and estimates of slip during 1797 and 1833 paleoearthquakes that are consistent with those produced from other techniques.
Propulsion Airframe Aeroacoustic Integration Effects for a Hybrid Wing Body Aircraft Configuration
NASA Technical Reports Server (NTRS)
Czech, Michael J.; Thomas, Russell H.; Elkoby, Ronen
2010-01-01
An extensive experimental investigation was performed to study the propulsion airframe aeroacoustic effects of a high bypass ratio engine for a hybrid wing body aircraft configuration where the engine is installed above the wing. The objective was to provide an understanding of the jet noise shielding effectiveness as a function of engine gas condition and location as well as nozzle configuration. A 4.7% scale nozzle of a bypass ratio seven engine was run at characteristic cycle points under static and forward flight conditions. The effect of the pylon and its orientation on jet noise was also studied as a function of bypass ratio and cycle condition. The addition of a pylon yielded significant spectral changes lowering jet noise by up to 4dB at high polar angles and increasing it by 2 to 3dB at forward angles. In order to assess jet noise shielding, a planform representation of the airframe model, also at 4.7% scale was traversed relative to the jet nozzle from downstream to several diameters upstream of the wing trailing edge. Installations at two fan diameters upstream of the wing trailing edge provided only limited shielding in the forward arc at high frequencies for both the axisymmetric and a conventional round nozzle with pylon. This was consistent with phased array measurements suggesting that the high frequency sources are predominantly located near the nozzle exit and, consequently, are amenable to shielding. The mid to low frequencies sources were observed further downstream and shielding was insignificant. Chevrons were designed and used to impact the distribution of sources with the more aggressive design showing a significant upstream migration of the sources in the mid frequency range. Furthermore, the chevrons reduced the low frequency source levels and the typical high frequency increase due to the application of chevron nozzles was successfully shielded. The pylon was further modified with a technology that injects air through the shelf of the pylon which was effective in reducing low frequency noise and moving jet noise sources closer to the nozzle exit. In general, shielding effectiveness varied as a function of cycle condition with the cutback condition producing higher shielding compared to sideline power. The configuration with a more strongly immersed chevron and a pylon oriented opposite to the microphones produced the largest reduction in jet noise. In addition to the jet noise source, the shielding of a broadband point noise source was documented with up to 20 dB of noise reduction at directivity angles directly under the shielding surface.
Yan, Sheng; Zhang, Jun; Yuan, Yuan; Lovrecz, George; Alici, Gursel; Du, Haiping; Zhu, Yonggang; Li, Weihua
2015-01-01
This work explores dielectrophoresis (DEP)-active hydrophoresis in sorting particles and cells. The device consists of prefocusing region and sorting region with great potential to be integrated into advanced lab-on-a-chip bioanalysis devices. Particles or cells can be focused in the prefocusing region and then sorted in the sorting region. The DEP-active hydrophoretic sorting is not only based on size but also on dielectric properties of the particles or cells of interest without any labelling. A mixture of 3 and 10 ?m particles were sorted and collected from corresponding outlets with high separation efficiency. According to the different dielectric properties of viable and nonviable Chinese Hamster Ovary (CHO) cells at the medium conductivity of 0.03 S/m, the viable CHO cells were focused well and sorted from cell sample with a high purity. PMID:25363719
NASA Astrophysics Data System (ADS)
Hua, H.; Owen, S. E.; Yun, S.; Lundgren, P.; Fielding, E. J.; Agram, P.; Manipon, G.; Stough, T. M.; Simons, M.; Rosen, P. A.; Wilson, B. D.; Poland, M. P.; Cervelli, P. F.; Cruz, J.
2013-12-01
Space-based geodetic measurement techniques such as Interferometric Synthetic Aperture Radar (InSAR) and Continuous Global Positioning System (CGPS) are now important elements in our toolset for monitoring earthquake-generating faults, volcanic eruptions, hurricane damage, landslides, reservoir subsidence, and other natural and man-made hazards. Geodetic imaging's unique ability to capture surface deformation with high spatial and temporal resolution has revolutionized both earthquake science and volcanology. Continuous monitoring of surface deformation and surface change before, during, and after natural hazards improves decision-making from better forecasts, increased situational awareness, and more informed recovery. However, analyses of InSAR and GPS data sets are currently handcrafted following events and are not generated rapidly and reliably enough for use in operational response to natural disasters. Additionally, the sheer data volumes needed to handle a continuous stream of InSAR data sets also presents a bottleneck. It has been estimated that continuous processing of InSAR coverage of California alone over 3-years would reach PB-scale data volumes. Our Advanced Rapid Imaging and Analysis for Monitoring Hazards (ARIA-MH) science data system enables both science and decision-making communities to monitor areas of interest with derived geodetic data products via seamless data preparation, processing, discovery, and access. We will present our findings on the use of hybrid-cloud computing to improve the timely processing and delivery of geodetic data products, integrating event notifications from USGS to improve the timely processing for response, as well as providing browse results for quick looks with other tools for integrative analysis.
Darne, Chinmay D.; Lu, Yujie; Tan, I-Chih; Zhu, Banghe; Rasmussen, John C.; Smith, Anne M.; Yan, Shikui; Sevick-Muraca, Eva M
2012-01-01
The work presented herein describes system design and performance evaluation of a miniaturized near-infrared fluorescence (NIRF) frequency-domain photon migration (FDPM) system with non-contact excitation and homodyne detection capability for small animal fluorescence tomography. The FDPM system was developed specifically for incorporation into a Siemens microPET/CT commercial scanner for hybrid small animal imaging, but could be adapted to other systems. Operating at 100 MHz, the system noise was minimized and the associated amplitude and phase errors were characterized to be ±0.7% and ±0.3°, respectively. To demonstrate the tomographic ability, a commercial mouse-shaped phantom with 50 ?M IRDye800CW and 68Ga containing inclusion was used to associate PET and NIRF tomography. 3-D mesh generation and anatomical referencing was accomplished through CT. A simplified spherical harmonics approximation (SP3) algorithm, for efficient prediction of light propagation in small animals, was tailored to incorporate FDPM approach. Finally, PET-NIRF target co-localization accuracy was analyzed in vivo with a dual-labeled imaging agent targeting orthotopic growth of human prostate cancer. The results obtained validate the integration of time-dependent fluorescence tomography system within a commercial microPET/CT scanner for multimodality small animal imaging. PMID:23171509
NASA Astrophysics Data System (ADS)
Jeništa, J.; Takana, H.; Nishiyama, H.; Bartlová, M.; Aubrecht, V.; K?enek, P.; Hrabovský, M.; Kavka, T.; Sember, V.; Mašláni, A.
2011-11-01
This paper presents a numerical investigation of characteristics and processes in the worldwide unique type of thermal plasma generator with combined stabilization of arc by argon flow and water vortex, the so-called hybrid-stabilized arc. The arc has been used for spraying of ceramic or metallic particles and for pyrolysis of biomass. The net emission coefficients as well as the partial characteristics methods for radiation losses from the argon-water arc are employed. Calculations for 300-600 A with 22.5-40 standard litres per minute (slm) of argon reveal transition from a transonic plasma flow for 400 A to a supersonic one for 600 A with a maximum Mach number of 1.6 near the exit nozzle of the plasma torch. A comparison with available experimental data near the exit nozzle shows very good agreement for the radial temperature profiles. Radial velocity profiles calculated 2 mm downstream of the nozzle exit show good agreement with the profiles determined from the combination of calculation and experiment (the so-called integrated approach). A recent evaluation of the Mach number from the experimental data for 500 and 600 A confirmed the existence of the supersonic flow regime.
NASA Astrophysics Data System (ADS)
Darne, Chinmay D.; Lu, Yujie; Tan, I.-Chih; Zhu, Banghe; Rasmussen, John C.; Smith, Anne M.; Yan, Shikui; Sevick-Muraca, Eva M.
2012-12-01
The work presented herein describes the system design and performance evaluation of a miniaturized near-infrared fluorescence (NIRF) frequency-domain photon migration (FDPM) system with non-contact excitation and homodyne detection capability for small animal fluorescence tomography. The FDPM system was developed specifically for incorporation into a Siemens micro positron emission tomography/computed tomography (microPET/CT) commercial scanner for hybrid small animal imaging, but could be adapted to other systems. Operating at 100 MHz, the system noise was minimized and the associated amplitude and phase errors were characterized to be ±0.7% and ±0.3°, respectively. To demonstrate the tomographic ability, a commercial mouse-shaped phantom with 50 µM IRDye800CW and 68Ga containing inclusion was used to associate PET and NIRF tomography. Three-dimensional mesh generation and anatomical referencing was accomplished through CT. A third-order simplified spherical harmonics approximation (SP3) algorithm, for efficient prediction of light propagation in small animals, was tailored to incorporate the FDPM approach. Finally, the PET-NIRF target co-localization accuracy was analyzed in vivo with a dual-labeled imaging agent targeting orthotopic growth of human prostate cancer. The obtained results validate the integration of time-dependent fluorescence tomography system within a commercial microPET/CT scanner for multimodality small animal imaging.
Monte Carlo methods Sequential Monte Carlo
Doucet, Arnaud
Monte Carlo methods Sequential Monte Carlo A. Doucet Carcans Sept. 2011 A. Doucet (MLSS Sept. 2011) Sequential Monte Carlo Sept. 2011 1 / 85 #12;Generic Problem Consider a sequence of probability distributions, Fn = Fn 1 F. A. Doucet (MLSS Sept. 2011) Sequential Monte Carlo Sept. 2011 2 / 85 #12;Generic Problem
B. J. Zhu; Y. L. Shi; M. C. Sukop; Y. B. Li; T. Y. Qin
2009-01-01
This work reports a new and accurate way of theoretical and numerical description of the extended 3D fluid (electromagnetic and flow) driven crack progression in co-seismic slip under P- and S-waves. First, based on the viscous fluid flow reciprocal work theorem, the hybrid hypersingular integral equation (HIE) method proposed by the author was defined by combined with the coupled extended
Chan-Chiao Lin; Zoran Filipi; Yongsheng Wang; Loucas Louca; Huei Peng; Dennis Assanis; Jeffrey Stein
2001-01-01
A hybrid electric vehicle simulation tool (HE-VESIM) has been developed at the Automotive Research Center of the University of Michigan to study the fuel economy potential of hybrid military\\/civilian trucks. In this paper, the fundamental architecture of the feed-forward parallel hybrid-electric vehicle system is described, together with dynamic equations and basic features of sub-system modules. Two vehicle-level power management control
Perkins, James Michael, 1978-
2007-01-01
A new heterogeneous integration technique has been developed and demonstrated to integrate vertical cavity surface emitting lasers (VCSELs) on silicon CMOS integrated circuits for optical interconnect applications. Individual ...
Song, Yong-Ha; Ahn, Sang-Joon Kenny; Kim, Min-Wu; Lee, Jeong-Oen; Hwang, Chi-Sun; Pi, Jae-Eun; Ko, Seung-Deok; Choi, Kwang-Wook; Park, Sang-Hee Ko; Yoon, Jun-Bo
2015-03-01
A hybrid complementary logic inverter consisting of an n-type oxide thin-film transistor (TFT) and a microelectromechanical system switch is proposed as a promising alternative to p-type oxide TFTs by S.-H. K. Park, J.-B. Yoon, and co-workers for ultralow power integrated circuits. Monolithically integrated heterogeneous microdevices are shown on a flexible substrate with a MEMS switch vertically stacked on top of the n-type oxide TFT. On page 1390, the logic device shows a distinctive voltage transfer characteristic curve, very low static leakage, zero-short circuit current, and exceedingly high voltage gain. PMID:25801828
G. G. Mekonnen; B. Huttl; H.-G. Bach; D. Pech; T. Rosin; C. Schubert; A. Konczykowska; F. Jorge; M. Riet
2008-01-01
A waveguide-integrated photodetector is hybrid packaged with an HBT-DEMUX into a receiver module for system experiments. The pin-DEMUX module has demonstrated an excellent RF behaviour at bit rates up to 80 Gb\\/s.
NASA Astrophysics Data System (ADS)
Joosten, A.; Bochud, F.; Moeckli, R.
2014-08-01
The comparison of radiotherapy techniques regarding secondary cancer risk has yielded contradictory results possibly stemming from the many different approaches used to estimate risk. The purpose of this study was to make a comprehensive evaluation of different available risk models applied to detailed whole-body dose distributions computed by Monte Carlo for various breast radiotherapy techniques including conventional open tangents, 3D conformal wedged tangents and hybrid intensity modulated radiation therapy (IMRT). First, organ-specific linear risk models developed by the International Commission on Radiological Protection (ICRP) and the Biological Effects of Ionizing Radiation (BEIR) VII committee were applied to mean doses for remote organs only and all solid organs. Then, different general non-linear risk models were applied to the whole body dose distribution. Finally, organ-specific non-linear risk models for the lung and breast were used to assess the secondary cancer risk for these two specific organs. A total of 32 different calculated absolute risks resulted in a broad range of values (between 0.1% and 48.5%) underlying the large uncertainties in absolute risk calculation. The ratio of risk between two techniques has often been proposed as a more robust assessment of risk than the absolute risk. We found that the ratio of risk between two techniques could also vary substantially considering the different approaches to risk estimation. Sometimes the ratio of risk between two techniques would range between values smaller and larger than one, which then translates into inconsistent results on the potential higher risk of one technique compared to another. We found however that the hybrid IMRT technique resulted in a systematic reduction of risk compared to the other techniques investigated even though the magnitude of this reduction varied substantially with the different approaches investigated. Based on the epidemiological data available, a reasonable approach to risk estimation would be to use organ-specific non-linear risk models applied to the dose distributions of organs within or near the treatment fields (lungs and contralateral breast in the case of breast radiotherapy) as the majority of radiation-induced secondary cancers are found in the beam-bordering regions.
Joosten, A; Bochud, F; Moeckli, R
2014-08-21
The comparison of radiotherapy techniques regarding secondary cancer risk has yielded contradictory results possibly stemming from the many different approaches used to estimate risk. The purpose of this study was to make a comprehensive evaluation of different available risk models applied to detailed whole-body dose distributions computed by Monte Carlo for various breast radiotherapy techniques including conventional open tangents, 3D conformal wedged tangents and hybrid intensity modulated radiation therapy (IMRT). First, organ-specific linear risk models developed by the International Commission on Radiological Protection (ICRP) and the Biological Effects of Ionizing Radiation (BEIR) VII committee were applied to mean doses for remote organs only and all solid organs. Then, different general non-linear risk models were applied to the whole body dose distribution. Finally, organ-specific non-linear risk models for the lung and breast were used to assess the secondary cancer risk for these two specific organs. A total of 32 different calculated absolute risks resulted in a broad range of values (between 0.1% and 48.5%) underlying the large uncertainties in absolute risk calculation. The ratio of risk between two techniques has often been proposed as a more robust assessment of risk than the absolute risk. We found that the ratio of risk between two techniques could also vary substantially considering the different approaches to risk estimation. Sometimes the ratio of risk between two techniques would range between values smaller and larger than one, which then translates into inconsistent results on the potential higher risk of one technique compared to another. We found however that the hybrid IMRT technique resulted in a systematic reduction of risk compared to the other techniques investigated even though the magnitude of this reduction varied substantially with the different approaches investigated. Based on the epidemiological data available, a reasonable approach to risk estimation would be to use organ-specific non-linear risk models applied to the dose distributions of organs within or near the treatment fields (lungs and contralateral breast in the case of breast radiotherapy) as the majority of radiation-induced secondary cancers are found in the beam-bordering regions. PMID:25082795
Young-Joo Lee; A. Emadi
2007-01-01
As the result of a wide range of efforts to improve fuel economy and reduce emissions of conventional vehicles, hybrid electric vehicle (HEV) technology has been commercialized. HEVs show better mile per gallon (MPG) than conventional vehicles. As a new practical breakthrough to reduce air pollution and fuel consumption, particularly in urban areas, converting HEVs into plug-in hybrid electric vehicles
Error in Monte Carlo, quasi-error in Quasi-Monte Carlo
R. H. Kleiss; A. Lazopoulos
2005-04-12
While the Quasi-Monte Carlo method of numerical integration achieves smaller integration error than standard Monte Carlo, its use in particle physics phenomenology has been hindered by the abscence of a reliable way to estimate that error. The standard Monte Carlo error estimator relies on the assumption that the points are generated independently of each other and, therefore, fails to account for the error improvement advertised by the Quasi-Monte Carlo method. We advocate the construction of an estimator of stochastic nature, based on the ensemble of pointsets with a particular discrepancy value. We investigate the consequences of this choice and give some first empirical results on the suggested estimators.
NASA Technical Reports Server (NTRS)
2002-01-01
[figure removed for brevity, see original site]
This image shows the rugged cratered highland region of Libya Montes. Libya Montes forms part of the rim of an ancient impact basin called Isidis. This region of the highlands is fairly dissected with valley networks. There is still debate within the scientific community as to how valley networks themselves form: surface runoff (rainfall/snowmelt) or headward erosion via groundwater sapping. The degree of dissection here in this region suggests surface runoff rather than groundwater sapping. Small dunes are also visible on the floors of some of these channels.
Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
Hybrid Computer Architectures Motivations for Research
Mohanty, Saraju P.
Hybrid Computer Architectures Motivations for Research What Is a Hybrid Processor? Hybrid commercial hybrid chips provide fixed processing cores and Field Programmable Gate Array (FPGA) elements an Application Specific Integrated Service (ASIC) can provide. How Do We Use Them? Hybrid chips seem uniquely
An Implicit Monte Carlo Method for Rarefied Gas Dynamics I: The Space Homogeneous Case.
Pareschi, Lorenzo
An Implicit Monte Carlo Method for Rarefied Gas Dynamics I: The Space Homogeneous Case. Lorenzo a hybrid Monte Carlo method that is robust in the fluid dynamic limit. This method is based on an analytic of the new method. Key Words: Boltzmann equation, MonteÂCarlo methods, fluid dyanmic limit, imÂ plicit time
D. Sabaripandiyan; S. Arul Daniel
2010-01-01
A comparative review is presented for integrated PEM Fuel Cell and Photovoltaic generating system to single phase utility grid. Different techniques of common coupling for integration have been investigated for this system. For both common AC bus and Common DC bus integration schemes, two different current control techniques have been investigated. The simulation result shows that common DC bus integration
Alwee, Razana; Shamsuddin, Siti Mariyam Hj; Sallehuddin, Roselina
2013-01-01
Crimes forecasting is an important area in the field of criminology. Linear models, such as regression and econometric models, are commonly applied in crime forecasting. However, in real crimes data, it is common that the data consists of both linear and nonlinear components. A single model may not be sufficient to identify all the characteristics of the data. The purpose of this study is to introduce a hybrid model that combines support vector regression (SVR) and autoregressive integrated moving average (ARIMA) to be applied in crime rates forecasting. SVR is very robust with small training data and high-dimensional problem. Meanwhile, ARIMA has the ability to model several types of time series. However, the accuracy of the SVR model depends on values of its parameters, while ARIMA is not robust to be applied to small data sets. Therefore, to overcome this problem, particle swarm optimization is used to estimate the parameters of the SVR and ARIMA models. The proposed hybrid model is used to forecast the property crime rates of the United State based on economic indicators. The experimental results show that the proposed hybrid model is able to produce more accurate forecasting results as compared to the individual models. PMID:23766729
NASA Astrophysics Data System (ADS)
Li, Wei; Wu, Tianlong; Wang, Wei; Guan, Jianguo; Zhai, Pengcheng
2014-01-01
Broadening the bandwidth of electromagnetic wave absorbers has greatly challenged material scientists. Here, we propose a two-layer hybrid absorber consisting of a non-planar metamaterial (MM) and a magnetic microwave absorbing material (MAM). The non-planar MM using magnetic MAMs instead of dielectric substrates shows good low frequency absorption and low reflection across a broad spectrum. Benefiting from this and the high frequency strong absorption of the MAM layer, the lightweight hybrid absorber exhibits 90% absorptivity over the whole 2-18 GHz range. Our result reveals a promising and flexible method to greatly extend or control the absorption bandwidth of absorbers.
NASA Technical Reports Server (NTRS)
Bavuso, Salvatore J.; Rothmann, Elizabeth; Dugan, Joanne Bechta; Trivedi, Kishor S.; Mittal, Nitin; Boyd, Mark A.; Geist, Robert M.; Smotherman, Mark D.
1994-01-01
The Hybrid Automated Reliability Predictor (HARP) integrated Reliability (HiRel) tool system for reliability/availability prediction offers a toolbox of integrated reliability/availability programs that can be used to customize the user's application in a workstation or nonworkstation environment. HiRel consists of interactive graphical input/output programs and four reliability/availability modeling engines that provide analytical and simulative solutions to a wide host of reliable fault-tolerant system architectures and is also applicable to electronic systems in general. The tool system was designed to be compatible with most computing platforms and operating systems, and some programs have been beta tested, within the aerospace community for over 8 years. Volume 1 provides an introduction to the HARP program. Comprehensive information on HARP mathematical models can be found in the references.
Hossein Kord; Ahmad Rohani
This paper introduces a method to unit sizing hybrid wind\\/Photovoltaic\\/Fuel Cell generation system for a typical domestic load that is not located near the electric grid. In this configuration the combination of a battery, an electrolyser, and a hydrogen storage tank are used as the energy storage system. The aim of this design is finding the configuration, among a set
Shuai Lu; Keith A. Corzine; Mehdi Ferdowsi
2007-01-01
This paper proposes a new energy storage system (ESS) design, including both batteries and ultracapacitors (UCs) in hybrid electric vehicle (HEV) and electric vehicle applications. The conventional designs require a DC-DC converter to interface the UC unit. Herein, the UC can be directly switched across the motor drive DC link during the peak power demands. The resulting wide voltage variation
Zuo, Peng; Dominguez, Delfina C.; Ye, Bang-Ce
2014-01-01
Infectious pathogens often cause serious public health concerns throughout the world. There is an increasing demand for simple, rapid and sensitive approaches for multiplexed pathogen detection. In this paper we have developed a polydimethylsiloxane (PDMS)/paper/glass hybrid microfluidic system integrated with aptamer-functionalized graphene oxide (GO) nano-biosensors for simple, one-step, multiplexed pathogen detection. The paper substrate used in this hybrid microfluidic system facilitated the integration of aptamer biosensors on the microfluidic biochip, and avoided complicated surface treatment and aptamer probe immobilization in a PDMS or glass-only microfluidic system. Lactobacillus acidophilus was used as a bacterium model to develop the microfluidic platform with a detection limit of 11.0 cfu mL?1. We have also successfully extended this method to the simultaneous detection of two infectious pathogens - Staphylococcus aureus and Salmonella enterica. This method is simple and fast. The one-step ‘turn on’ pathogen assay in a ready-to-use microfluidic device only takes ~10 min to complete on the biochip. Furthermore, this microfluidic device has great potential in rapid detection of a wide variety of different other bacterial and viral pathogens. PMID:23929394
Monte Carlo EM for Generalized Linear Mixed Models using Randomized Spherical Radial
Booth, James
Monte Carlo EM for Generalized Linear Mixed Models using Randomized Spherical Radial Integration by Monte Carlo methods. However, in practice, the Monte Carlo sample sizes required for convergence for such methods. One solution is to use Monte Carlo approximation, as proposed by Wei and Tanner (1990
Susan R. Hertz
2002-01-01
This paper describes an approach to speech synthesis in which waveform fragments dynamically produced with a set of formant-based synthesis rules are concatenated with pre-stored natural speech waveform fragments to produce a synthetic utterance. While this hybrid approach was originally implemented as a tool for research into improved voice quality in formant-based synthesis, it has produced such good results that
Advanced Integrated Bidirectional AC\\/DC and DC\\/DC Converter for Plug-In Hybrid Electric Vehicles
Young-Joo Lee; Alireza Khaligh; Ali Emadi
2009-01-01
Hybrid electric vehicle (HEV) technology provides an effective solution for achieving higher fuel economy, better performance, and lower emissions, compared with conventional vehicles. Plug-in HEVs (PHEVs) are HEVs with plug-in capabilities and provide a more all-electric range; hence, PHEVs improve fuel economy and reduce emissions even more. PHEVs have a battery pack of high energy density and can run solely
Kinetic Monte Carlo with fields: diffusion in heterogeneous systems
NASA Astrophysics Data System (ADS)
Alfredo Caro, Jose
2011-03-01
It is commonly perceived that to achieve breakthrough scientific discoveries in the 21^st century an integration of world leading experimental capabilities with theory, computational modeling and high performance computer simulations is necessary. Lying between the atomic and the macro scales, the meso scale is crucial for advancing materials research. Deterministic methods result computationally too heavy to cover length and time scales relevant for this scale. Therefore, stochastic approaches are one of the options of choice. In this talk I will describe recent progress in efficient parallelization schemes for Metropolis and kinetic Monte Carlo [1-2], and the combination of these ideas into a new hybrid Molecular Dynamics-kinetic Monte Carlo algorithm developed to study the basic mechanisms taking place in diffusion in concentrated alloys under the action of chemical and stress fields, incorporating in this way the actual driving force emerging from chemical potential gradients. Applications are shown on precipitation and segregation in nanostructured materials. Work in collaboration with E. Martinez, LANL, and with B. Sadigh, P. Erhart and A. Stukowsky, LLNL. Supported by the Center for Materials at Irradiation and Mechanical Extremes, an Energy Frontier Research Center funded by the U.S. Department of Energy (Award # 2008LANL1026) at Los Alamos National Laboratory [4pt] [1] B. Sadigh et al. to be published [2] E. Martinez et al. J. Comp. Phys. 227 (2008) 3804-3823
Iterative acceleration methods for Monte Carlo and deterministic criticality calculations
Urbatsch, T.J.
1995-11-01
If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors.
Kim, Jaiseung, E-mail: jkim@nbi.dk [Niels Bohr Institute and Discovery Center, Blegdamsvej 17, DK-2100 Copenhagen (Denmark)
2011-04-01
We have made a Markov Chain Monte Carlo (MCMC) analysis of primordial non-Gaussianity (f{sub NL}) using the WMAP bispectrum and power spectrum. In our analysis, we have simultaneously constrained f{sub NL} and cosmological parameters so that the uncertainties of cosmological parameters can properly propagate into the f{sub NL} estimation. Investigating the parameter likelihoods deduced from MCMC samples, we find slight deviation from Gaussian shape, which makes a Fisher matrix estimation less accurate. Therefore, we have estimated the confidence interval of f{sub NL} by exploring the parameter likelihood without using the Fisher matrix. We find that the best-fit values of our analysis make a good agreement with other results, but the confidence interval is slightly different.
Zaeytijd, J. de [Department of Information Technology (INTEC), Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Gent (Belgium)], E-mail: jurgen.dezaeytijd@intec.ugent.be; Bogaert, I.; Franchois, A. [Department of Information Technology (INTEC), Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Gent (Belgium)
2008-07-01
Electromagnetic scattering problems involving inhomogeneous objects can be numerically solved by applying a Method of Moments discretization to the volume integral equation. For electrically large problems, the iterative solution of the resulting linear system is expensive, both computationally and in memory use. In this paper, a hybrid MLFMA-FFT method is presented, which combines the fast Fourier transform (FFT) method and the High Frequency Multilevel Fast Multipole Algorithm (MLFMA) in order to reduce the cost of the matrix-vector multiplications needed in the iterative solver. The method represents the scatterers within a set of possibly disjoint identical cubic subdomains, which are meshed using a uniform cubic grid. This specific mesh allows for the application of FFTs to calculate the near interactions in the MLFMA and reduces the memory cost considerably, since the aggregation and disaggregation matrices of the MLFMA can be reused. Additional improvements to the general MLFMA framework, such as an extention of the FFT interpolation scheme of Sarvas et al. from the scalar to the vectorial case in combination with a more economical representation of the radiation patterns on the lowest level in vector spherical harmonics, are proposed and the choice of the subdomain size is discussed. The hybrid method performs better in terms of speed and memory use on large sparse configurations than both the FFT method and the HF MLFMA separately and it has lower memory requirements on general large problems. This is illustrated on a number of representative numerical test cases.
Improved conversion efficiency of as-grown InGaN/GaN quantum-well solar cells for hybrid integration
NASA Astrophysics Data System (ADS)
Valdueza-Felip, Sirona; Mukhtarova, Anna; Grenet, Louis; Bougerol, Catherine; Durand, Christophe; Eymery, Joel; Monroy, Eva
2014-03-01
We report on the photovoltaic characteristics of solar cells based on 15 and 30 InxGa1-xN/GaN (x = 0.10 and 0.19) multiquantum wells (MQWs) grown on sapphire. Doubling the number of MQWs increases the peak external quantum efficiency by a factor of 2 for both In contents. Devices with 19% In, with a spectral cutoff at 465 nm, exhibit an open-circuit voltage of 1.7 V and a short-circuit current density of 3.00 mA/cm2 under 1 sun AM1.5G illumination, leading to a conversion efficiency of 2.00%, making them promising for hybrid integration with non-III-nitride photovoltaic devices.
NASA Astrophysics Data System (ADS)
Liu, Siqi; Weng, Bo; Tang, Zi-Rong; Xu, Yi-Jun
2014-12-01
A ternary hybrid structure of one-dimensional (1D) silver nanowire-doped reduced graphene oxide (RGO) integrated with a CdS nanowire (NW) network has been fabricated via a simple electrostatic self-assembly method followed by a hydrothermal reduction process. The electrical conductivity of RGO can be significantly enhanced by opening up new conduction channels by bridging the high resistance grain-boundaries (HGBs) with 1D Ag nanowires, which results in a prolonged lifetime of photo-generated charge carriers excited from the CdS NW network, thus making Ag NW-RGO an efficient co-catalyst with the CdS NW network toward artificial photosynthesis.A ternary hybrid structure of one-dimensional (1D) silver nanowire-doped reduced graphene oxide (RGO) integrated with a CdS nanowire (NW) network has been fabricated via a simple electrostatic self-assembly method followed by a hydrothermal reduction process. The electrical conductivity of RGO can be significantly enhanced by opening up new conduction channels by bridging the high resistance grain-boundaries (HGBs) with 1D Ag nanowires, which results in a prolonged lifetime of photo-generated charge carriers excited from the CdS NW network, thus making Ag NW-RGO an efficient co-catalyst with the CdS NW network toward artificial photosynthesis. Electronic supplementary information (ESI) available: Experimental details, photographs of the experimental setups for photocatalytic activity testing, SEM images of Ag NWs and CdS NWs, Zeta potential, Raman spectra, DRS spectra, PL spectra and PL decay time evolution, and photocatalytic performances of samples for reduction of 4-NA and recycling test. See DOI: 10.1039/c4nr04229h
C. E. Berger; E. R. Anderson; J. E. Drut
2014-10-29
We determine the ground-state energy and Tan's contact of attractively interacting few-fermion systems in a one-dimensional harmonic trap, for a range of couplings and particle numbers. To this end, we implement a new lattice Monte Carlo approach based on a non-uniform discretization of space, defined via Gauss-Hermite quadrature points and weights. This particular coordinate basis is natural for systems in harmonic traps, and it yields a position-dependent coupling and a corresponding non-uniform Hubbard-Stratonovich transformation. The resulting path integral is performed with hybrid Monte Carlo as a proof of principle for calculations at finite temperature and in higher dimensions.
NASA Astrophysics Data System (ADS)
Li, Hongbo; Wu, Zai-Sheng; Shen, Zhifa; Shen, Guoli; Yu, Ruqin
2014-01-01
An interesting discovery is reported in that G-rich hairpin-based recognition probes can self-assemble into a nano-architecture based on the integration of an intermolecular G-quadruplex structure with the sticky-end pairing effect in the presence of target DNAs. Moreover, GNPs modified with partly complementary DNAs can intensively aggregate by hybridization-based intercalation between intermolecular G-quadruplexes, indicating an inspiring assembly mechanism and a powerful colorimetric DNA detection. The proposed intermolecular G-quadruplex-integrated sticky-end pairing assembly (called GISA)-based colorimetric system allows a specific and quantitative assay of p53 DNA with a linear range of more than two orders of magnitude and a detection limit of 0.2 nM, suggesting a considerably improved analytical performance. And more to the point, the discrimination of single-base mismatched target DNAs can be easily conducted via visual observation. The successful development of the present colorimetric system, especially the GISA-based aggregation mechanism of GNPs is different from traditional approaches, and offers a critical insight into the dependence of the GNP aggregation on the structural properties of oligonucleotides, opening a good way to design colorimetric sensing probes and DNA nanostructure. An interesting discovery is reported in that G-rich hairpin-based recognition probes can self-assemble into a nano-architecture based on the integration of an intermolecular G-quadruplex structure with the sticky-end pairing effect in the presence of target DNAs. Moreover, GNPs modified with partly complementary DNAs can intensively aggregate by hybridization-based intercalation between intermolecular G-quadruplexes, indicating an inspiring assembly mechanism and a powerful colorimetric DNA detection. The proposed intermolecular G-quadruplex-integrated sticky-end pairing assembly (called GISA)-based colorimetric system allows a specific and quantitative assay of p53 DNA with a linear range of more than two orders of magnitude and a detection limit of 0.2 nM, suggesting a considerably improved analytical performance. And more to the point, the discrimination of single-base mismatched target DNAs can be easily conducted via visual observation. The successful development of the present colorimetric system, especially the GISA-based aggregation mechanism of GNPs is different from traditional approaches, and offers a critical insight into the dependence of the GNP aggregation on the structural properties of oligonucleotides, opening a good way to design colorimetric sensing probes and DNA nanostructure. Electronic supplementary information (ESI) available: Experimental section, supplementary Figures and perspectives. See DOI: 10.1039/c3nr03547f
Mineralogy of Libya Montes, Mars
NASA Astrophysics Data System (ADS)
Perry, K. A.; Bishop, J. L.; McKeown, N. K.
2009-12-01
Observations by CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) have revealed a range of minerals in Libya Montes including olivine, pyroxene, and phyllosilicate [1]. Here we extend our spectral analyses of CRISM images in Libya Montes to identify carbonates. We have also performed detailed characterization of the spectral signature of the phyllosilicate- and carbonate-bearing outcrops in order to constrain the types of phyllosilicates and carbonates present. Phyllosilicate-bearing rocks in Libya Montes have spectral bands at 1.42, 2.30 and 2.39 µm, consistent with Fe- and Mg- bearing smectites. The mixture of Fe and Mg in Libya Montes may be within the clay mineral structure or within the CRISM pixel. Because the pixels have 18 meter/pixel spatial resolution, it is possible that the bands observed are due to the mixing of nontronite and saponite rather than a smectite with both Fe and Mg. Carbonates found in Libya Montes are similar to those found in Nili Fossae [2]. The carbonates have bands centered at 2.30 and 2.52 µm. Libya Montes carbonates most closely resemble the Mg-carbonate, magnesite. Olivine spectra are seen throughout Libya Montes, characterized by a positive slope from 1.2-1.8 µm. Large outcrops of olivine are relatively rare on Mars [3]. This implies that fresh bedrock has been recently exposed because olivine weathers readily compared to pyroxene and feldspar. Pyroxene in Libya Montes resembles an Fe-bearing orthopyroxene with a broad band centered at 1.82 µm. The lowermost unit identified in Libya Montes is a clay-bearing unit. Overlying this is a carbonate-bearing unit with a clear unit division visible in at least one CRISM image. An olivine-bearing unit unconformably overlies these two units and may represent a drape related to the Isidis impact, as suggested for Nili Fossae [2]. However, it appears that the carbonate in Libya Montes is an integral portion of the rock underlying the olivine-bearing unit rather than an alteration product, contrasting with proposed stratigraphy for Nili Fossae. The uppermost unit identified is a pyroxene-bearing unit. Some spectra of clays and carbonates in this region present a slope from 1.2 to 1.8 µm similar to olivine. Laboratory experiments were conducted in attempt to understand the relationship of mixtures including olivine, nontronite, and magnesite. The characteristic olivine slope is evident in the spectra in any mixture, even with as little as 10% olivine. In ternary mixtures, the magnesite is almost completely overshadowed by the nontronite and olivine characteristics. The discovery of clays and carbonates in Libya Montes indicates that there was an aqueous environment with neutral pH in the past. In addition, water needs to be relatively still and deep for the small particles to precipitate out and form into the minerals. On Earth, this would be a still lake or deep ocean, and perhaps a similar environment may have been present here in Mars’ past. References [1] Bishop, J. L., et al. (2007) 7th Int'l Mars Conf. [2] Ehlmann, B. L., et al. (2008) Science, 322, 1828. [3] Mustard, J. F., et al. (2008) Nature, 454, 07305.
NASA Astrophysics Data System (ADS)
Shimao, Xiao; Yunfeng, Yu; Chengyan, Ma; Tianchun, Ye; Ming, Yin
2010-03-01
The design consideration and implementation of a CMOS frequency synthesizer for the portable hybrid global navigation satellite system are presented. The large tuning range is achieved by tuning curve compensation using an improved VCO resonant tank, which reduces the power consumption and obtains better phase noise performance. The circuit is validated by simulations and fabricated in a standard 0.18 ?m 1P6M CMOS process. Close-loop phase noise measured is lower than -95 dBc at 200 kHz offset while the measured tuning range is 21.5% from 1.47 to 1.83 GHz. The proposed synthesizer including source coupled logic prescaler consumes 6.2 mA current from 1.8 V supply. The whole silicon required is only 0.53 mm2.
Shell model Monte Carlo methods
Koonin, S.E. [California Inst. of Tech., Pasadena, CA (United States). W.K. Kellogg Radiation Lab.; Dean, D.J. [Oak Ridge National Lab., TN (United States)
1996-10-01
We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, thermal behavior of {gamma}-soft nuclei, and calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. 87 refs.
Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William
2005-09-01
ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 5.0, the latest version of ITS, contains (1) improvements to the ITS 3.0 continuous-energy codes, (2) multigroup codes with adjoint transport capabilities, (3) parallel implementations of all ITS codes, (4) a general purpose geometry engine for linking with CAD or other geometry formats, and (5) the Cholla facet geometry library. Moreover, the general user friendliness of the software has been enhanced through increased internal error checking and improved code portability.
Kumar, Ramesh; Pal, Parimal
2015-02-01
Experimental investigations were carried out on continuous and direct production of poly-(?-glutamic acid) in a hybrid reactor system that integrated conventional fermentative production step with membrane-based downstream separation and purification. Novelty of the integrated system lies in high degree of purity, conversion, yield and productivity of poly-(?-glutamic acid) through elimination of substrate-product inhibitions of traditional batch production system. This new system is compact, flexible, eco-friendly and largely fouling-free ensuring steady and continuous production of poly-(?-glutamic acid) directly from a renewable carbon source at the rate of 0.91 g/L/h. Cross-flow microfiltration membrane modules ensured almost complete separation and recycle of cells without much fouling problem. Well-screened ultrafiltration membrane module helped to concentrate poly-(?-glutamic acid) while ensuring recovery and recycle of 96% unconverted carbon source resulting in yield of 0.6g/g along with high product purity. PMID:25484125
NASA Technical Reports Server (NTRS)
Sproles, Darrell W.; Bavuso, Salvatore J.
1994-01-01
The Hybrid Automated Reliability Predictor (HARP) integrated Reliability (HiRel) tool system for reliability/availability prediction offers a toolbox of integrated reliability/availability programs that can be used to customize the user's application in a workstation or nonworkstation environment. HiRel consists of interactive graphical input/output programs and four reliability/availability modeling engines that provide analytical and simulative solutions to a wide host of highly reliable fault-tolerant system architectures and is also applicable to electronic systems in general. The tool system was designed at the outset to be compatible with most computing platforms and operating systems and some programs have been beta tested within the aerospace community for over 8 years. This document is a user's guide for the HiRel graphical postprocessor program HARPO (HARP Output). HARPO reads ASCII files generated by HARP. It provides an interactive plotting capability that can be used to display alternate model data for trade-off analyses. File data can also be imported to other commercial software programs.
2010-01-01
Background Azalea (Rhododendron simsii hybrids) is the most important flowering pot plant produced in Belgium, being exported world-wide. In the breeding program, flower color is the main feature for selection, only in later stages cultivation related plant quality traits are evaluated. As a result, plants with attractive flowering are kept too long in the breeding cycle. The inheritance of flower color has been well studied; information on the heritability of cultivation related quality traits is lacking. For this purpose, QTL mapping in diverse genetic backgrounds appeared to be a must and therefore 4 mapping populations were made and analyzed. Results An integrated framework map on four individual linkage maps in Rhododendron simsii hybrids was constructed. For genotyping, mainly dominant scored AFLP (on average 364 per population) and MYB-based markers (15) were combined with co-dominant SSR (23) and EST markers (12). Linkage groups were estimated in JoinMap. A consensus grouping for the 4 mapping populations was made and applied in each individual mapping population. Finally, 16 stable linkage groups were set for the 4 populations; the azalea chromosome number being 13. A combination of regression mapping (JoinMap) and multipoint-likelihood maximization (Carthagène) enabled the construction of 4 maps and their alignment. A large portion of loci (43%) was common to at least two populations and could therefore serve as bridging markers. The different steps taken for map optimization and integration into a reference framework map for QTL mapping are discussed. Conclusions This is the first map of azalea up to our knowledge. AFLP and SSR markers are used as a reference backbone and functional markers (EST and MYB) were added as candidate genes for QTL analysis. The alignment of the 4 maps on the basis of framework markers will facilitate in turn the alignment of QTL regions detected in each of the populations. The approach we took is thoroughly different than the recently published integrated maps and well-suited for mapping in a non-model crop. PMID:20070894
A. Ganguly; D. Misra; S. Ghosh
2010-01-01
This paper presents the modeling and analysis of a greenhouse-integrated power system consisting of solar photovoltaic panels, electrolyzer bank and Polymer Electrolyte Membrane (PEM) fuel cell stacks. Electric power is generated in an array of solar photovoltaic modules. Excess energy after meeting the requirements of the greenhouse during peak sunshine hours, is supplied to an electrolyzer bank to generate hydrogen
Kushner, Mark
, the plasma potential and stochastic electron heating produced by the substrate bias may not be well at the sheath edge. Results from the integrated model for an inductively coupled plasma etching reactor in these reactors. Inductively coupled plasma ICP reactors are one high plasma density tool which provide uniform
ERIC Educational Resources Information Center
Reisslein, Jana; Seeling, Patrick; Reisslein, Martin
2005-01-01
An important challenge in the introductory communication networks course in electrical and computer engineering curricula is to integrate emerging topics, such as wireless Internet access and network security, into the already content-intensive course. At the same time it is essential to provide students with experiences in online collaboration,…
NASA Astrophysics Data System (ADS)
Zhu, B. J.; Shi, Y. L.; Sukop, M. C.
2009-04-01
Strong earthquakes can have catastrophic effects on society, and therefore the precise prediction of large earthquakes is crucial for seismic hazard reduction. The genesis and occurrence of earthquakes and their subsequent effects involve complex physical processes. Studying these processes helps us understand the mechanics of earthquakes and the future physical state of the earth. Earthquake studies focus on the nucleation of rupture, thermo- and hydro-mechanical weakening of fault zones during seismic slip, fracture propagation through branched and offset fault systems, and relations between stress, seismicity, and deformation in or near continental and subduction fault systems. Fluid driven fracture is a fundamental geophysical phenomenon operating in planetary interiors on many scales; it plays a major role in chemical differentiation of the upper mantle and dynamic delayed triggering of earthquakes process. Because our ability to make direct observation of the dynamics and styles of fluid driven fracture is quite limited, our understanding of this phenomenon relies on theoretical models that use fundamental physical principles and available field data to constrain the behavior of fluid driven cracks at depth. However, relatively little work has been done on 3D extended fluid driven crack propagation. This seems to be due mainly to the present limitations on practical methods (such as CPU time and storage requirements) and on theoretical aspects (strongly singular domain integrals). This requires general and accurate theoretical method. This work reports a new and accurate way of theoretical and numerical description of the extended 3D fluid (electromagnetic and flow) driven crack progression in saturated porous media for P- and S-waves under fully coupled electromagnetothermoelastic field. First, based on the viscous fluid flow reciprocal work theorem, the hybrid hypersingular integral equation (HIE) method proposed by the author was defined by combined with the coupled extended wave time-domain HIE, the lattice Boltzmann method and the interface phase field method. The general extended 3D fluid flow velocity wave solutions are obtained by the extended wave time-domains Green's function method. The 3D extended dynamic fluid driven crack modeling under fully coupled electromagnetothermoelastic P- and S-wave and flow field was established. Then, the problem is reduced to solving a set of extended hybrid HIEs coupled with nonlinear boundary domain integral equations, in which the unknown functions are the general extended flow velocity discontinuity waves. The behavior of the general extended singular stress indices around the crack front terminating is analyzed by hybrid time-domain main-part analysis. The general extended singular pore stress waves (SPSWs) and the extended dynamic stress intensity factors (DSIFs) on the fluid driven crack surface are obtained from closed-form solutions. In addition, a numerical method for the problem is proposed, in which the extended velocity discontinuity waves are approximated by the product of time-domain density functions and polynomials. The extended DSIFs and general extended SPSWs are calculated, and the results are presented toward demonstrating the applicability of the proposed method. Key words 3D fluid driven crack propagation mechanism; P- and S-waves; Fully coupled electromagnetothermoelastic field; Hypersingular integral method, Lattice Boltzmann method; Interface phase field method; Extended dynamic stress intensity factor; General extended singular pore stress waves.
Hybrid solar-fossil fuel power generation
Sheu, Elysia J. (Elysia Ja-Zeng)
2012-01-01
In this thesis, a literature review of hybrid solar-fossil fuel power generation is first given with an emphasis on system integration and evaluation. Hybrid systems are defined as those which use solar energy and fuel ...
Brown, F.B.; Sutton, T.M.
1996-02-01
This report is composed of the lecture notes from the first half of a 32-hour graduate-level course on Monte Carlo methods offered at KAPL. These notes, prepared by two of the principle developers of KAPL`s RACER Monte Carlo code, cover the fundamental theory, concepts, and practices for Monte Carlo analysis. In particular, a thorough grounding in the basic fundamentals of Monte Carlo methods is presented, including random number generation, random sampling, the Monte Carlo approach to solving transport problems, computational geometry, collision physics, tallies, and eigenvalue calculations. Furthermore, modern computational algorithms for vector and parallel approaches to Monte Carlo calculations are covered in detail, including fundamental parallel and vector concepts, the event-based algorithm, master/slave schemes, parallel scaling laws, and portability issues.
Romand, Raymond; Ripp, Raymond; Poidevin, Laetitia; Boeglin, Marcel; Geffers, Lars; Dollé, Pascal; Poch, Olivier
2015-01-01
An in situ hybridization (ISH) study was performed on 2000 murine genes representing around 10% of the protein-coding genes present in the mouse genome using data generated by the EURExpress consortium. This study was carried out in 25 tissues of late gestation embryos (E14.5), with a special emphasis on the developing ear and on five distinct developing sensory organs, including the cochlea, the vestibular receptors, the sensory retina, the olfactory organ, and the vibrissae follicles. The results obtained from an analysis of more than 11,000 micrographs have been integrated in a newly developed knowledgebase, called ImAnno. In addition to managing the multilevel micrograph annotations performed by human experts, ImAnno provides public access to various integrated databases and tools. Thus, it facilitates the analysis of complex ISH gene expression patterns, as well as functional annotation and interaction of gene sets. It also provides direct links to human pathways and diseases. Hierarchical clustering of expression patterns in the 25 tissues revealed three main branches corresponding to tissues with common functions and/or embryonic origins. To illustrate the integrative power of ImAnno, we explored the expression, function and disease traits of the sensory epithelia of the five presumptive sensory organs. The study identified 623 genes (out of 2000) concomitantly expressed in the five embryonic epithelia, among which many (?12%) were involved in human disorders. Finally, various multilevel interaction networks were characterized, highlighting differential functional enrichments of directly or indirectly interacting genes. These analyses exemplify an under-represention of "sensory" functions in the sensory gene set suggests that E14.5 is a pivotal stage between the developmental stage and the functional phase that will be fully reached only after birth. PMID:25706271
Ryo Nagase; Akira Himeno; Masayuki Okuno; Kuniharu Kato; Ken-Ichi Yukimatsu; Masao Kawachi
1994-01-01
A compact, low-crosstalk 8×8 optical matrix switch module has been developed. A thermooptic switch chip and driving circuits with TTL interfaces are integrated on a 100-mm2 ceramic substrate. It achieved a low insertion loss of 10.0 dB, a low crosstalk level of -25.9 dB, and had excellent stability in practical operation. A photonic intermodule connector for electronic switching systems in
Duncavage, Eric J.; Magrini, Vincent; Becker, Nils; Armstrong, Jon R.; Demeter, Ryan T.; Wylie, Todd; Abel, Haley J.; Pfeifer, John D.
2011-01-01
Although next-generation sequencing (NGS) has been the domain of large genome centers, it is quickly becoming more accessible to general pathology laboratories. In addition to finding single-base changes, NGS allows for the detection of larger structural variants, including insertions/deletions, translocations, and viral insertions. We describe the use of targeted NGS on DNA extracted from formalin-fixed, paraffin-embedded (FFPE) tissue, and show that the short read lengths of NGS are ideally suited to fragmented DNA obtained from FFPE tissue. Further, we describe a novel method for performing hybrid-capture target enrichment using PCR-generated capture probes. As a model, we captured the 5.3-kb Merkel cell polyomavirus (MCPyV) genome in FFPE cases of Merkel cell carcinoma using inexpensive, PCR-derived capture probes, and achieved up to 37,000-fold coverage of the MCPyV genome without prior virus-specific PCR amplification. This depth of coverage made it possible to reproducibly detect viral genome deletions and insertion sites anywhere within the human genome. Out of four cases sequenced, we identified the 5? insertion sites in four of four cases and the 3? sites in three of four cases. These findings demonstrate the potential for an inexpensive gene targeting and NGS method that can be easily adapted for use with FFPE tissue to identify large structural rearrangements, opening up the possibility for further discovery from archival tissue. PMID:21497292
Quantum Monte Carlo Method for Attractive Coulomb Potentials
J. S. Kole; H. De Raedt
2001-02-06
Starting from an exact lower bound on the imaginary-time propagator, we present a Path-Integral Quantum Monte Carlo method that can handle singular attractive potentials. We illustrate the basic ideas of this Quantum Monte Carlo algorithm by simulating the ground state of hydrogen and helium.
Recent Advances in Randomized Quasi-Monte Carlo Methods
Pierre L’Ecuyer; Christiane Lemieux
We survey some of the recent developments on quasi-Monte Carlo (QMC) methods, which, in their basic form, are a deterministic counterpart to the Monte Carlo (MC) method. Our main focus is the applicability of these methods to practical problems that involve the estimation of a high-dimensional integral. We review several QMC constructions and different randomizations that have been proposed to
Inverse Monte Carlo: a unified reconstruction algorithm for SPECT
Carey E. Floyd; R. E. Coleman; R. J. Jaszczak
1985-01-01
Inverse Monte Carlo (IMOC) is presented as a unified reconstruction algorithm for Emission Computed Tomography (ECT) providing simultaneous compensation for scatter, attenuation, and the variation of collimator resolution with depth. The technique of inverse Monte Carlo is used to find an inverse solution to the photon transport equation (an integral equation for photon flux from a specified source) for a
NSDL National Science Digital Library
2013-06-21
In this video, we become familiar with integrals, both by understanding them as sums of areas under plots of functions, and by understanding them as anti-derivatives. We present the u-substitution rule, which is the analog of the chain rule for differentiating composite functions.
NSDL National Science Digital Library
2014-09-18
At its core, the LEGO® MINDSTORMS® NXT product provides a programmable microprocessor. Students use the NXT processor to simulate an experiment involving thousands of uniformly random points placed within a unit square. Using the underlying geometry of the experimental model, as well as the geometric definition of the constant ? (pi), students form an empirical ratio of areas to estimate a numerical value of ?. Although typically used for numerical integration of irregular shapes, in this activity, students use a Monte Carlo simulation to estimate a common but rather complex analytical form—the numerical value of the most famous irrational number, ?.
Luo, Ye; Chamanzar, Maysamreza; Apuzzo, Aniello; Salas-Montiel, Rafael; Nguyen, Kim Ngoc; Blaize, Sylvain; Adibi, Ali
2015-02-11
The enhancement and confinement of electromagnetic radiation to nanometer scale have improved the performances and decreased the dimensions of optical sources and detectors for several applications including spectroscopy, medical applications, and quantum information. Realization of on-chip nanofocusing devices compatible with silicon photonics platform adds a key functionality and provides opportunities for sensing, trapping, on-chip signal processing, and communications. Here, we discuss the design, fabrication, and experimental demonstration of light nanofocusing in a hybrid plasmonic-photonic nanotaper structure. We discuss the physical mechanisms behind the operation of this device, the coupling mechanisms, and how to engineer the energy transfer from a propagating guided mode to a trapped plasmonic mode at the apex of the plasmonic nanotaper with minimal radiation loss. Optical near-field measurements and Fourier modal analysis carried out using a near-field scanning optical microscope (NSOM) show a tight nanofocusing of light in this structure to an extremely small spot of 0.00563(?/(2n(rmax)))(3) confined in 3D and an exquisite power input conversion of 92%. Our experiments also verify the mode selectivity of the device (low transmission of a TM-like input mode and high transmission of a TE-like input mode). A large field concentration factor (FCF) of about 4.9 is estimated from our NSOM measurement with a radius of curvature of about 20 nm at the apex of the nanotaper. The agreement between our theory and experimental results reveals helpful insights about the operation mechanism of the device, the interplay of the modes, and the gradual power transfer to the nanotaper apex. PMID:25562706
Schichtel, B.A.; Malm, W.C.; Gebhart, K.A.; Barna, M.G.; Knipping, E.M. [Colorado State University, Ft. Collins, CO (United States)
2006-04-04
The Big Bend Regional Aerosol and Visibility (BRAVO) study was an intensive air quality study designed to understand the causes of haze in Big Bend National Park. Daily speciated fine aerosols were measured from July through October 1999 at 37 sites located mostly in Texas. In support of BRAVO, two chemical transport models (CTMs) were used to apportion particulate sulfate at Big Bend and other sites in Texas to sources in the eastern and western United States, Texas, Mexico, and the Carbon I and II coal-fired power plants, located 225 km southeast of Big Bend in Mexico. Analysis of the CTM source attribution results and comparison to results from receptor models revealed systematic biases. To reduce the multiplicative biases, a hybrid source apportionment model, based on inverse modeling, was developed that adjusted the initial CTM source contributions so the modeled sulfate concentrations optimally fit the measured data, resulting in refined daily source contributions. The method was tested using synthetic data and successfully reduced source attribution biases. The refined sulfate source attribution results reduced the initial eastern U.S. contribution to Big Bend, averaged over the BRAVO study period, from about 40% to about 30%, while Mexico's contribution increased from 24 - 32% about 40%. The contribution from the Carbon facility increased from similar to 14% to over 20%. The increase in Mexico's contribution is consistent with more recent SO{sub 2} emissions estimates that indicate that the BRAVO Mexican SO{sub 2} emissions were underestimated. Source attribution results for other monitoring sites in west Texas were similar to results at Big Bend.
Monte Carlo method in optical radiometry
A. V. Prokhorov
1998-01-01
State-of-the-art in the application of the Monte Carlo method (MCM) to the computational problems of optical radiometry is discussed. The MCM offers a universal technique for radiation transfer modelling based on the stochastic approach. Developments of the original MCM algorithms and software for calculation of effective emissivities of black bodies, absorption characteristics of cavity radiometers and photometric properties of integrating
Jeong, Hee Jin; Kim, Ho Young; Jeong, Hyun; Han, Joong Tark; Jeong, Seung Yol; Baeg, Kang-Jun; Jeong, Mun Seok; Lee, Geon-Woong
2014-05-28
We present a straightforward method for simultaneously enhancing the electrical conductivity, environmental stability, and photocatalytic properties of graphene films through one-step transfer of CVD graphene and integration by introducing TiO2/graphene oxide layer. A highly durable and flexible TiO2 layer is successfully used as a supporting layer for graphene transfer instead of the commonly used PMMA. Transferred graphene/TiO2 film is directly used for measuring the carrier transport and optoelectronic properties without an extra TiO2 removal and following deposition steps for multifunctional integration into devices because the thin TiO2 layer is optically transparent and electrically semiconducting. Moreover, the TiO2 layer induces charge screening by electrostatically interacting with the residual oxygen moieties on graphene, which are charge scattering centers, resulting in a reduced current hysteresis. Adsorption of water and other chemical molecules onto the graphene surface is also prevented by the passivating TiO2 layer, resulting in the long term environmental stability of the graphene under high temperature and humidity. In addition, the graphene/TiO2 film shows effectively enhanced photocatalytic properties because of the increase in the transport efficiency of the photogenerated electrons due to the decrease in the injection barrier formed at the interface between the F-doped tin oxide and TiO2 layers. PMID:24578338
Powers, J J
2011-11-28
This study focused on creating a new tristructural isotropic (TRISO) coated particle fuel performance model and demonstrating the integration of this model into an existing system of neutronics and heat transfer codes, creating a user-friendly option for including fuel performance analysis within system design optimization and system-level trade-off studies. The end product enables both a deeper understanding and better overall system performance of nuclear energy systems limited or greatly impacted by TRISO fuel performance. A thorium-fueled hybrid fusion-fission Laser Inertial Fusion Energy (LIFE) blanket design was used for illustrating the application of this new capability and demonstrated both the importance of integrating fuel performance calculations into mainstream design studies and the impact that this new integrated analysis had on system-level design decisions. A new TRISO fuel performance model named TRIUNE was developed and verified and validated during this work with a novel methodology established for simulating the actual lifetime of a TRISO particle during repeated passes through a pebble bed. In addition, integrated self-consistent calculations were performed for neutronics depletion analysis, heat transfer calculations, and then fuel performance modeling for a full parametric study that encompassed over 80 different design options that went through all three phases of analysis. Lastly, side studies were performed that included a comparison of thorium and depleted uranium (DU) LIFE blankets as well as some uncertainty quantification work to help guide future experimental work by assessing what material properties in TRISO fuel performance modeling are most in need of improvement. A recommended thorium-fueled hybrid LIFE engine design was identified with an initial fuel load of 20MT of thorium, 15% TRISO packing within the graphite fuel pebbles, and a 20cm neutron multiplier layer with beryllium pebbles in flibe molten salt coolant. It operated at a system power level of 2000 MW{sub th}, took about 3.5 years to reach full plateau power, and was capable of an End of Plateau burnup of 38.7 %FIMA if considering just the neutronic constraints in the system design; however, fuel performance constraints led to a maximum credible burnup of 12.1 %FIMA due to a combination of internal gas pressure and irradiation effects on the TRISO materials (especially PyC) leading to SiC pressure vessel failures. The optimal neutron spectrum for the thorium-fueled blanket options evaluated seemed to favor a hard spectrum (low but non-zero neutron multiplier thicknesses and high TRISO packing fractions) in terms of neutronic performance but the fuel performance constraints demonstrated that a significantly softer spectrum would be needed to decrease the rate of accumulation of fast neutron fluence in order to improve the maximum credible burnup the system could achieve.
NASA Astrophysics Data System (ADS)
Powers, Jeffrey J.
2011-12-01
This study focused on creating a new tristructural isotropic (TRISO) coated particle fuel performance model and demonstrating the integration of this model into an existing system of neutronics and heat transfer codes, creating a user-friendly option for including fuel performance analysis within system design optimization and system-level trade-off studies. The end product enables both a deeper understanding and better overall system performance of nuclear energy systems limited or greatly impacted by TRISO fuel performance. A thorium-fueled hybrid fusion-fission Laser Inertial Fusion Energy (LIFE) blanket design was used for illustrating the application of this new capability and demonstrated both the importance of integrating fuel performance calculations into mainstream design studies and the impact that this new integrated analysis had on system-level design decisions. A new TRISO fuel performance model named TRIUNE was developed and verified and validated during this work with a novel methodology established for simulating the actual lifetime of a TRISO particle during repeated passes through a pebble bed. In addition, integrated self-consistent calculations were performed for neutronics depletion analysis, heat transfer calculations, and then fuel performance modeling for a full parametric study that encompassed over 80 different design options that went through all three phases of analysis. Lastly, side studies were performed that included a comparison of thorium and depleted uranium (DU) LIFE blankets as well as some uncertainty quantification work to help guide future experimental work by assessing what material properties in TRISO fuel performance modeling are most in need of improvement. A recommended thorium-fueled hybrid LIFE engine design was identified with an initial fuel load of 20MT of thorium, 15% TRISO packing within the graphite fuel pebbles, and a 20cm neutron multiplier layer with beryllium pebbles in flibe molten salt coolant. It operated at a system power level of 2000 MWth, took about 3.5 years to reach full plateau power, and was capable of an End of Plateau burnup of 38.7 %FIMA if considering just the neutronic constraints in the system design; however, fuel performance constraints led to a maximum credible burnup of 12.1 %FIMA due to a combination of internal gas pressure and irradiation effects on the TRISO materials (especially PyC) leading to SiC pressure vessel failures. The optimal neutron spectrum for the thorium-fueled blanket options evaluated seemed to favor a hard spectrum (low but non-zero neutron multiplier thicknesses and high TRISO packing fractions) in terms of neutronic performance but the fuel performance constraints demonstrated that a significantly softer spectrum would be needed to decrease the rate of accumulation of fast neutron fluence in order to improve the maximum credible burnup the system could achieve.
Fiedoruk, Marta; Cocovi-Solberg, David J; Tymecki, ?ukasz; Koncki, Robert; Miró, Manuel
2015-02-01
An integrated Sequential Injection (SI)/Flow Injection (FI) system furnished with a miniaturized LED-based fluorometric detector is presented in this work for expedient bioaccessibility tests of orthophosphate in soils. Equipped with a microcolumn of conical shape containing 50 mg of soil, the hybrid flow system was resorted to on-line dynamic leaching and real-time quantification of pools of mobilizable orthophosphate using a bi-directional syringe pump and multiposition valve. The flexibility of the flow manifold was harnessed to explore both bi-directional and uni-directional flow extraction modes with the added degree of freedom of on-line dilution of extracts whenever needed. Bioaccessible orthophosphate was split in three fractions, the so-called NH4Cl fraction containing labile exchangeable phosphates, the alkaline fraction with Fe and Al-bound phosphates and the acidic fraction containing Ca-bound phosphates. The prevailing molybdenum blue photometric detection method is replaced by spectrofluorometric detection based on the ion pair formation between the phosphomolybdate heteropolyacid and rhodamine B with the subsequent quenching of the dye fluorescence. The dedicated optoelectronic detector was integrated in a secondary FI manifold and operated according to the fluorometric paired emitter-detector diode (FPEDD) principle involving two light emitting diodes as fluorescence inductors and one as detector of LED-induced fluorescence. Demonstrated with the analysis of a standard reference material (SRM 2711) and a real agricultural soil, the developed FI/SI fractionation system with FPEDD detection is proven reliable against the standard molybdenum blue method (p>0.05), and useful for investigation of the leaching kinetics of orthophosphate in bioaccessibility tests through in-line recording of the extraction profiles. PMID:25435227
Quasi-Monte Carlo methods for lattice systems: A first look
NASA Astrophysics Data System (ADS)
Jansen, K.; Leovey, H.; Ammon, A.; Griewank, A.; Müller-Preussker, M.
2014-03-01
We investigate the applicability of quasi-Monte Carlo methods to Euclidean lattice systems for quantum mechanics in order to improve the asymptotic error behavior of observables for such theories. In most cases the error of an observable calculated by averaging over random observations generated from an ordinary Markov chain Monte Carlo simulation behaves like N, where N is the number of observations. By means of quasi-Monte Carlo methods it is possible to improve this behavior for certain problems to N-1, or even further if the problems are regular enough. We adapted and applied this approach to simple systems like the quantum harmonic and anharmonic oscillator and verified an improved error scaling. Catalogue identifier: AERJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERJ_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence version 3 No. of lines in distributed program, including test data, etc.: 67759 No. of bytes in distributed program, including test data, etc.: 2165365 Distribution format: tar.gz Programming language: C and C++. Computer: PC. Operating system: Tested on GNU/Linux, should be portable to other operating systems with minimal efforts. Has the code been vectorized or parallelized?: No RAM: The memory usage directly scales with the number of samples and dimensions: Bytes used = “number of samples” × “number of dimensions” × 8 Bytes (double precision). Classification: 4.13, 11.5, 23. External routines: FFTW 3 library (http://www.fftw.org) Nature of problem: Certain physical models formulated as a quantum field theory through the Feynman path integral, such as quantum chromodynamics, require a non-perturbative treatment of the path integral. The only known approach that achieves this is the lattice regularization. In this formulation the path integral is discretized to a finite, but very high dimensional integral. So far only Monte Carlo, and especially Markov chain-Monte Carlo methods like the Metropolis or the hybrid Monte Carlo algorithm have been used to calculate approximate solutions of the path integral. These algorithms often lead to the undesired effect of autocorrelation in the samples of observables and suffer in any case from the slow asymptotic error behavior proportional to N, if N is the number of samples. Solution method: This program applies the quasi-Monte Carlo approach and the reweighting technique (respectively the weighted uniform sampling method) to generate uncorrelated samples of observables of the anharmonic oscillator with an improved asymptotic error behavior. Unusual features: The application of the quasi-Monte Carlo approach is quite revolutionary in the field of lattice field theories. Running time: The running time depends directly on the number of samples N and dimensions d. On modern computers a run with up to N=216=65536 (including 9 replica runs) and d=100 should not take much longer than one minute.
Yoon, Ki-Hong; Oh, Su Hwan; Kim, Ki Soo; Kwon, O-Kyun; Oh, Dae Kon; Noh, Young-Ouk; Lee, Hyung-Jong
2010-03-15
We presented a hybridly-integrated tunable external cavity laser with 0.8 nm mode spacing 16 channels operating in the direct modulation of 2.5-Gbps for a low-cost source of a WDM-PON system. The tunable laser was fabricated by using a superluminescent diode (SLD) and a polymer Bragg reflector. The maximum output power and the power slope efficiency of the tunable laser were 10.3 mW and 0.132 mW/mA, respectively, at the SLD current of 100 mA and the temperature of 25 degrees C. The directly-modulated tunable laser successfully provided 2.5-Gbps transmissions through 20-km standard single mode fiber. The power penalty of the tunable laser was less than 0.8 dB for 16 channels after a 20-km transmission. The power penalty variation was less than 1.4 dB during the blue-shifted wavelength tuning. PMID:20389571
NASA Astrophysics Data System (ADS)
Li, L.; Wang, K.; Li, H.; Eibert, T. F.
2014-11-01
A hybrid higher-order finite element boundary integral (FE-BI) technique is discussed where the higher-order FE matrix elements are computed by a fully analytical procedure and where the gobal matrix assembly is organized by a self-identifying procedure of the local to global transformation. This assembly procedure applys to both, the FE part as well as the BI part of the algorithm. The geometry is meshed into three-dimensional tetrahedra as finite elements and nearly orthogonal hierarchical basis functions are employed. The boundary conditions are implemented in a strong sense such that the boundary values of the volume basis functions are directly utilized within the BI, either for the tangential electric and magnetic fields or for the asssociated equivalent surface current densities by applying a cross product with the unit surface normals. The self-identified method for the global matrix assembly automatically discerns the global order of the basis functions for generating the matrix elements. Higher order basis functions do need more unknowns for each single FE, however, fewer FEs are needed to achieve the same satisfiable accuracy. This improvement provides a lot more flexibility for meshing and allows the mesh size to raise up to ?/3. The performance of the implemented system is evaluated in terms of computation time, accuracy and memory occupation, where excellent results with respect to precision and computation times of large scale simulations are found.
A Parallel Quasi-Monte Carlo Method for Computing Extremal Eigenvalues
Mascagni, Michael
A Parallel Quasi-Monte Carlo Method for Computing Extremal Eigenvalues Michael Mascagni1 and Aneta The convergence of Monte Carlo methods for numerical integration can often be improved by replacing pseudorandom). In this paper the convergence of a Monte Carlo method for evaluating the extremal eigenvalues of a given matrix
NASA Astrophysics Data System (ADS)
Kwak, Eunju
The development of sensor technologies and the increase in user requirements have resulted in many different approaches for efficient building model generation. Three-dimensional building models are important in various applications, such as disaster management and urban planning. Despite this importance, generation of these models lacks economical and reliable techniques which take advantage of the available multi-sensory data from single and multiple platforms. Therefore, this research develops a framework for fully-automated building model generation by integrating data-driven and model-driven methods as well as exploiting the advantages of images and LiDAR datasets. The building model generation starts by employing LiDAR data for building detection and approximate boundary determination. The generated building boundaries are then integrated into a model-based image processing strategy, because LiDAR derived planes show irregular boundaries due to the nature of LiDAR point acquisition. The focus of the research is generating models for the buildings with right-angled-corners, which can be described with a collection of rectangles (e.g., L-shape, T-shape, U-shape, gable roofs, and more complex building shapes which are combinations of the aforementioned shapes), under the assumption that the majority of the buildings in urban areas belong to this category. Therefore, by applying the Minimum Bounding Rectangle (MBR) algorithm recursively, the LiDAR boundaries are decomposed into sets of rectangles for further processing. At the same time the quality of the MBRs are examined to verify that the buildings, from which the boundaries are generated, are buildings with right-angled-corners. These rectangles are preliminary model primitives. The parameters that define the model primitives are adjusted using detected edges in the imagery through the least-squares adjustment procedure, i.e., model-based image fitting. The level of detail in the final Digital Building Model is based on the number of recursions during the MBR processing, which in turn are determined by the LiDAR point density. The model-based image fitting refines the search space and resolves the matching ambiguities in multiple images, which results in higher quality boundaries. This research thus develops an approach which not only automates the building model generation, but also improves the accuracy of the building model itself.
High-coherence semiconductor lasers based on integral high-Q resonators in hybrid Si/III-V platforms
Santis, Christos Theodoros; Steger, Scott T.; Vilenchik, Yaakov; Vasilyev, Arseny; Yariv, Amnon
2014-01-01
The semiconductor laser (SCL) is the principal light source powering the worldwide optical fiber network. The ever-increasing demand for data is causing the network to migrate to phase-coherent modulation formats, which place strict requirements on the temporal coherence of the light source that no longer can be met by current SCLs. This failure can be traced directly to the canonical laser design, in which photons are both generated and stored in the same, optically lossy, III-V material. This leads to an excessive and large amount of noisy spontaneous emission commingling with the laser mode, thereby degrading its coherence. High losses also decrease the amount of stored optical energy in the laser cavity, magnifying the effect of each individual spontaneous emission event on the phase of the laser field. Here, we propose a new design paradigm for the SCL. The keys to this paradigm are the deliberate removal of stored optical energy from the lossy III-V material by concentrating it in a passive, low-loss material and the incorporation of a very high-Q resonator as an integral (i.e., not externally coupled) part of the laser cavity. We demonstrate an SCL with a spectral linewidth of 18 kHz in the telecom band around 1.55 ?m, achieved using a single-mode silicon resonator with Q of 106. PMID:24516134
Reactive path integral quantum simulations of molecules solvated in superfluid helium
NASA Astrophysics Data System (ADS)
Walewski, ?ukasz; Forbert, Harald; Marx, Dominik
2014-03-01
A hybrid ab initio path integral molecular dynamics/bosonic path integral Monte Carlo simulation method has been developed, implemented and tested, which allows for the reactive simulations of molecules, clusters or complexes solvated by superfluid 4He. The simulation takes into account “on-the-fly” the electronic structure and thus the chemical reactivity of the solutes, in conjunction with the Bose-Einstein statistics, and thus the superfluid character of this peculiar solvent. This enables investigations into cryochemical reactions taking place in helium nanodroplets, such as those used in helium nanodroplet isolation (HENDI) spectroscopy.
Hybrid control for the Pendubot
Mingjun Zhang; Tzyh-Jong Tarn
2001-01-01
A new hybrid controller has been applied for feedback stabilization of a Pendubot, whose dynamics show second order nonholonomic properties. Experimental results for different test cases show that the hybrid control outperforms the existing control algorithm. This successful implementation provides a novel alternative for the control of under-actuated mechanical systems. Many such systems are subject to second order non-integrable differential
Cramer, S.N.
1984-01-01
The MORSE code is a large general-use multigroup Monte Carlo code system. Although no claims can be made regarding its superiority in either theoretical details or Monte Carlo techniques, MORSE has been, since its inception at ORNL in the late 1960s, the most widely used Monte Carlo radiation transport code. The principal reason for this popularity is that MORSE is relatively easy to use, independent of any installation or distribution center, and it can be easily customized to fit almost any specific need. Features of the MORSE code are described.
Monte Carlo methods Monte Carlo Principle and MCMC
Doucet, Arnaud
Monte Carlo methods Monte Carlo Principle and MCMC A. Doucet Carcans Sept. 2011 A. Doucet (MLSS Sept. 2011) MCMC Sept. 2011 1 / 91 #12;Overview of the Lectures 1 Monte Carlo Principles A. Doucet (MLSS Sept. 2011) MCMC Sept. 2011 2 / 91 #12;Overview of the Lectures 1 Monte Carlo Principles 2 Markov
Enhancements in Continuous-Energy Monte Carlo Capabilities in SCALE
Bekar, Kursat B [ORNL] [ORNL; Celik, Cihangir [ORNL] [ORNL; Wiarda, Dorothea [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Rearden, Bradley T [ORNL] [ORNL; Dunn, Michael E [ORNL] [ORNL
2013-01-01
Monte Carlo tools in SCALE are commonly used in criticality safety calculations as well as sensitivity and uncertainty analysis, depletion, and criticality alarm system analyses. Recent improvements in the continuous-energy data generated by the AMPX code system and significant advancements in the continuous-energy treatment in the KENO Monte Carlo eigenvalue codes facilitate the use of SCALE Monte Carlo codes to model geometrically complex systems with enhanced solution fidelity. The addition of continuous-energy treatment to the SCALE Monaco code, which can be used with automatic variance reduction in the hybrid MAVRIC sequence, provides significant enhancements, especially for criticality alarm system modeling. This paper describes some of the advancements in continuous-energy Monte Carlo codes within the SCALE code system.
Diagrammatic Monte Carlo and Worm Algorithm Techniques
NASA Astrophysics Data System (ADS)
Prokof'ev, Nikolay
This chapter reviews basic principles of Diagrammatic Monte Carlo and Worm Algorithm techniques. Diagrammatic Monte Carlo establishes generic rules for unbiased sampling of well defined configuration spaces when the only source of errors is of statistical origin due to finite sampling time, no matter whether configuration parameters involve discrete, as in the Ising model, or continuous, as in Feynman diagrams or lattice path integrals, variables. Worm Algorithms allow one to sample efficiently configuration spaces with complex topology and non-local constraints which cause severe problems for Monte Carlo schemes based on local updates. They achieve this goal by working with the enlarged configuration space which includes configurations violating constraints present in the original formulation.
NASA Astrophysics Data System (ADS)
Robinson, Patrick J.
Gasification has been used in industry on a relatively limited scale for many years, but it is emerging as the premier unit operation in the energy and chemical industries. The switch from expensive and insecure petroleum to solid hydrocarbon sources (coal and biomass) is occurring due to the vast amount of domestic solid resources, national security and global warming issues. Gasification (or partial oxidation) is a vital component of "clean coal" technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel gas for driving combustion turbines. Gasification units in a chemical plant generate synthesis gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The coupling of an Integrated Gasification Combined Cycle (IGCC) with a methanol plant can handle swings in power demand by diverting hydrogen gas from a combustion turbine and synthesis gas from the gasifier to a methanol plant for the production of an easily-stored, hydrogen-consuming liquid product. An additional control degree of freedom is provided with this hybrid plant, fundamentally improving the controllability of the process. The idea is to base-load the gasifier and use the more responsive gas-phase units to handle disturbances. During the summer days, power demand can fluctuate up to 50% over a 12-hour period. The winter provides a different problem where spikes of power demand can go up 15% within the hour. The following dissertation develops a hybrid IGCC / methanol plant model, validates the steady-state results with a National Energy Technical Laboratory study, and tests a proposed control structure to handle these significant disturbances. All modeling was performed in the widely used chemical process simulators Aspen Plus and Aspen Dynamics. This dissertation first presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. Limitations in the software dealing with solids make this a necessary task. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudo fuel. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macro-scale thermal, flow, composition and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers, but merely presents an idea of how to dynamically simulate coal gasification in an approximate way. This dissertation also presents models of the downstream units of a typical IGCC. Dynamic simulations of the H2S absorption/stripping unit, Water-gas Shift (WGS) reactors, and CO2 absorption/stripping unit are essential for the development of stable and agile plantwide control structures of this hybrid power/chemical plant. Due to the high pressure of the system, hydrogen sulfide is removed by means of physical absorption. SELEXOLRTM (a mixture of the dimethyl ethers of polyethylene glycol) is used to achieve a gas purity of less than 5 ppm H2S. This desulfurized synthesis gas is sent to two water gas shift reactors that convert a total of 99% of carbon monoxide to hydrogen. Physical absorption of carbon dioxide with Selexol produces a hydrogen rich stream (90 mol% H2) to be fed into combustion turbines or to a methanol plant. Steady-state economic designs and plantwide control structures are developed in this dissertation. A steady-state economic design, control structure, and successful turndown of the methanol plant are shown in this dissertation. The Plantwide control structure and interaction among units are also shown. The methanol plant was si
Brown, F.B.
1981-01-01
Examination of the global algorithms and local kernels of conventional general-purpose Monte Carlo codes shows that multigroup Monte Carlo methods have sufficient structure to permit efficient vectorization. A structured multigroup Monte Carlo algorithm for vector computers is developed in which many particle events are treated at once on a cell-by-cell basis. Vectorization of kernels for tracking and variance reduction is described, and a new method for discrete sampling is developed to facilitate the vectorization of collision analysis. To demonstrate the potential of the new method, a vectorized Monte Carlo code for multigroup radiation transport analysis was developed. This code incorporates many features of conventional general-purpose production codes, including general geometry, splitting and Russian roulette, survival biasing, variance estimation via batching, a number of cutoffs, and generalized tallies of collision, tracklength, and surface crossing estimators with response functions. Predictions of vectorized performance characteristics for the CYBER-205 were made using emulated coding and a dynamic model of vector instruction timing. Computation rates were examined for a variety of test problems to determine sensitivities to batch size and vector lengths. Significant speedups are predicted for even a few hundred particles per batch, and asymptotic speedups by about 40 over equivalent Amdahl 470V/8 scalar codes arepredicted for a few thousand particles per batch. The principal conclusion is that vectorization of a general-purpose multigroup Monte Carlo code is well worth the significant effort required for stylized coding and major algorithmic changes.
Improved geometry representations for Monte Carlo radiation transport.
Martin, Matthew Ryan (Cornell University)
2004-08-01
ITS (Integrated Tiger Series) permits a state-of-the-art Monte Carlo solution of linear time-integrated coupled electron/photon radiation transport problems with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. ITS allows designers to predict product performance in radiation environments.
Monte Python: Monte Carlo code for CLASS in Python
NASA Astrophysics Data System (ADS)
Audren, Benjamin; Lesgourgues, Julien; Benabed, Karim; Prunet, Simon
2013-07-01
Monte Python is a parameter inference code which combines the flexibility of the python language and the robustness of the cosmological code CLASS into a simple and easy to manipulate Monte Carlo Markov Chain code.
NASA Astrophysics Data System (ADS)
Buscheck, T. A.; Chen, M.; Lu, C.; Sun, Y.; Hao, Y.; Elliot, T. R.; Celia, M. A.; Bielicki, J. M.
2012-12-01
The challenges of mitigating climate change and generating sustainable renewable energy are inseparable and can be addressed by synergistic integration of geothermal energy production with secure geologic CO2 storage (GCS). Pressure buildup can be a limiting factor for GCS and geothermal reservoir operations, due to a number of concerns, including the potential for CO2 leakage and induced seismicity, while pressure depletion can limit geothermal energy recovery. Water-use demands can also be a limiting factor for GCS and geothermal operations, particularly where water resources are already scarce. Economic optimization of geothermal-GCS involves trade-offs of various benefits and risks, along with their associated costs: (1) heat extraction per ton of delivered CO2, (2) permanent CO2 storage, (3) energy recovery per unit well (and working-fluid recirculation) costs, and (4) economic lifetime of a project. We analyze a hybrid, multi-stage approach using both formation brine and injected CO2 as working fluids to attempt to optimize the benefits of sustainable energy production and permanent CO2 storage, while conserving water resources and minimizing environmental risks. We consider a range of well-field patterns and operational schemes. Initially, the fluid production is entirely brine. After CO2 breakthrough, the fraction of CO2 in production, which is called the CO2 "cut", increases with time. Thus, brine is the predominant working fluid for early time, with the contribution of CO2 to heat extraction increasing with CO2 cut (and time). We find that smaller well spacing between CO2 injectors and producers favors earlier CO2 breakthrough and a more rapid rise in CO2 cut, which increases the contribution of recirculated CO2, thereby improving the heat extraction per ton of delivered CO2. On the other hand, larger well spacing increases permanent CO2 storage, energy production per unit well cost, while reducing the thermal drawdown rate, which extends the economic lifetime of a project. For the range of cases considered, we were never able to eliminate the co-production of brine; thus, brine management is likely to be important for reservoir operations, whether or not brine is considered as a candidate working fluid. Future work will address site-specific reservoir conditions and infrastructure factors, such as proximity to potential CO2 sources. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Hybrid organic-inorganic optoelectronic subsystems on a chip
Louay Eldada; Junichiro Fujita; Antonije Radojevic; Reinald Gerhardt; Tomoyuki Izuhara
2005-01-01
We report on hybrid organic-inorganic optoelectronic sysbsystems that integrate passive and active optical functions. The integration approaches involve various levels of hybridization, from splicing of pigtailed elements, to chip-to-chip attachment, to hybrid on-chip integration involving grafting and flip-chip mounting, and finally to true heteroepitaxy. The materials integrated include polymer, silica, silicon, silicon oxynitride, lithium niobate, indium phosphide, gallium arsenide, yttrium
G. Groeneweg
This paper explores the card game Machi- avelli. 1 In this game, many turns have to be played and many actions can be carried out per turn, which results in a large game tree. Because traditional search methods will take too much time to play the game in a reasonable amount of time, this paper deals with applying Monte Carlo
NASA Astrophysics Data System (ADS)
Micheloni, R.; Crippa, L.; Picca, M.
In recent years, both industry and academia have increased their research effort in the hybrid memory management space, developing a wide variety of systems. It is worth mentioning that "hybrid" is a generic term and it can have different meanings depending on the context. For instance, a storage system can be hybrid because it combines HDD and SSD; an SSD can be hybrid because it combines SLC and MLC Flash memories, or it combines different non-volatile memories like NAND and ReRAM. In this chapter we look at all these different meanings.
Experiments with Monte Carlo Othello
Philip Hingston; Martin Masek
2007-01-01
In this paper, we report on our experiments with using Monte Carlo simulation (specifically the UCT algorithm) as the basis for an Othello playing program. Monte Carlo methods have been used for other games in the past, most recently and notably in successful Go playing programs. We show that Monte Carlo-based players have potential for Othello, and that evolutionary algorithms
Monte Carlo photon benchmark problems
Whalen, D.J.; Hollowell, D.E.; Hendricks, J.S.
1991-01-01
Photon benchmark calculations have been performed to validate the MCNP Monte Carlo computer code. These are compared to both the COG Monte Carlo computer code and either experimental or analytic results. The calculated solutions indicate that the Monte Carlo method, and MCNP and COG in particular, can accurately model a wide range of physical problems.
Monte-Carlo Tests Diplomarbeit
Monte-Carlo Tests Diplomarbeit Wiebke Werft Mathematisches Institut der Heinrich.2 Suffizienz und VollstÃ¤ndigkeit . . . . . . . . . . . . . . . . . . . . 5 2 Monte-Carlo Tests 8 2.1 Formulierung des Testproblems . . . . . . . . . . . . . . . . . . . 8 2.2 Definition des Monte-Carlo Tests
Quantum Monte Carlo Helsinki 2011
Boyer, Edmond
Quantum Monte Carlo Helsinki 2011 Marius Lewerenz MSME/CT, UMR 8208 CNRS, UniversitÂ´e Paris Est? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 What is a Monte Carlo method? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3 What are Monte Carlo methods good for? . . . . . . . . . . . . . . . . . . . . . . . 5 1
2014-01-01
Background The aim of this study was to evaluate the value of CA15-3 for the diagnostic integration of molecular imaging findings performed with hybrid positron emission tomography and computed tomography (PETCT) technology. Methods We retrospectively selected 45 patients with a median age of 60 years (range 39–85 years) and a previous history of breast cancer (BC) who had already been treated with surgery and other treatments. Three measurements of CA15-3 were collected within 1 year before PETCT examination, at 6–9 months 3–6 months and 0–3 months before PETCT. The prolonged clinical outcome or imaging follow-up was used to define disease relapse. An increase in tumor marker value was compared with PETCT findings and disease relapse. Sensitivity and specificity for both tests were calculated with respect to clinical outcome. Results Disease relapse was detected in 16 out of 45 BC patients. CA15-3 and PETCT showed 75% sensitivity with a specificity percentage of 76% for CA15-3 and 79% for PETCT. Serum CA15-3 expression levels were significantly higher in BC patients with multiple metastatic sites with hepatic involvement. Analysis of serial CA15-3 serum levels showed an increase in CA15-3 3–6 months before PETCT could identify BC patients at risk for relapse (AUC?=?0.81). Moreover, patients receiving anti-hormonal or chemotherapy medications with negative PETCT and positive CA15-3 relapsed after a median time of 158 days compared to patients who were negative for both tests and who were free from disease for at least 1 year. Conclusions Our results showed that serial increases in CA15-3 can be used to predict positive PETCT results in BC patients during follow-up. Increased levels of CA15-3 may be considered an early warning sign in patients needing accurate molecular imaging investigations, as they are at higher risk of recurrence. In cases of elevated levels, multiple lesions or liver involvement may exist. Also, patients receiving chemotherapeutic or anti-hormonal treatment who have negative PETCT scans and increased CA15-3 serum levels should be considered at risk for relapse, because the CA15-3-linked biochemical signal of the presence of a tumor can predict positive metabolic imaging. PMID:24886519
NSDL National Science Digital Library
The first site takes you to the very informative essay at Motor Trend's site on its car of the year, the Toyota Prius (1). The next site is from the Union of Concerned Scientists. This great resource, called Clean Vehicles, offers all sorts of info about vehicles for the future (2). The Department of Energy's Hybrid Electric Vehicle Program page (3 ) offers lots of good information about the technology surrounding the cars as well as information on how you can get a tax break if you buy one. In fairness to both Honda (4 ) (Note: Honda also makes the Insight) and Toyota (5 ) these two sites take you to their webpages devoted to their two comparable hybrid cars, the Honda Civic Hybrid and the Toyota Prius. The last site takes you to a recent story on NPR about the future of hybrid technology and hybrid SUVs (6 )
ERIC Educational Resources Information Center
Beckwith, E. George; Cunniff, Daniel T.
2009-01-01
Online course enrollment has increased dramatically over the past few years. The authors cite the reasons for this rapid growth and the opportunities open for enhancing teaching/learning techniques such as video conferencing and hybrid class combinations. The authors outlined an example of an accelerated learning, eight-class session course…
Dytman, Steven [Department.of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States)
2011-10-06
Every neutrino experiment requires a Monte Carlo event generator for various purposes. Historically, each series of experiments developed their own code which tuned to their needs. Modern experiments would benefit from a universal code (e.g. PYTHIA) which would allow more direct comparison between experiments. GENIE attempts to be that code. This paper compares most commonly used codes and provides some details of GENIE.
NASA Astrophysics Data System (ADS)
Dytman, Steven
2011-10-01
Every neutrino experiment requires a Monte Carlo event generator for various purposes. Historically, each series of experiments developed their own code which tuned to their needs. Modern experiments would benefit from a universal code (e.g. PYTHIA) which would allow more direct comparison between experiments. GENIE attempts to be that code. This paper compares most commonly used codes and provides some details of GENIE.
Exact pseudofermion action for Monte Carlo simulation of domain-wall fermion
NASA Astrophysics Data System (ADS)
Chen, Yu-Chih; Chiu, Ting-Wai
2014-11-01
We present an exact pseudofermion action for hybrid Monte Carlo simulation (HMC) of one-flavor domain-wall fermion (DWF), with the effective 4-dimensional Dirac operator equal to the optimal rational approximation of the overlap-Dirac operator with kernel H = cHw(1 + d?5Hw) - 1, where c and d are constants. Using this exact pseudofermion action, we perform HMC of one-flavor QCD, and compare its characteristics with the widely used rational hybrid Monte Carlo algorithm (RHMC). Moreover, to demonstrate the practicality of the exact one-flavor algorithm (EOFA), we perform the first dynamical simulation of the (1 + 1)-flavors QCD with DWF.
Luk, Wayne
Optimizing Floating Point Units in Hybrid FPGAs ChiWai Yu, Alastair M. Smith, Wayne Luk, Fellow, IEEE, Philip London, London SW7 2BT, U.K. (e-mail: yuchiwai@gmail.com; wl@doc.ic.ac.uk). A. M. Smith is with the Department of Electrical and Electronic Engineering, Imperial College London, South Kensington SW7 2BT, U.K
NSDL National Science Digital Library
This animated YouTube video, created by Southwest Center for Microsystems Education (SCME), illustrates how DNA hybridization works in the context of nanofabrication. The animation and associated narration describe "DNA hybridization is when a single-stranded DNA (ssDNA) molecule bonds with a complementary ssDNA molecule from another source forming a "hybrid". This animation shows a double-stranded DNA (dsDNA) molecule dividing into two ssDNA strands. One ssDNA remains on the substrate as the "probe". A complementary ssDNA from another source (a ssDNA with a complementary base pair sequence) joins with the probe forming a 'hybrid' dsDNA molecule." A supporting learning module and activities can be downloaded from the SCME website.
C. A. Meyer; E. S. Swanson
2015-03-04
A review of the theoretical and experimental status of hybrid hadrons is presented. The states $\\pi_1(1400)$, $\\pi_1(1600)$, and $\\pi_1(2015)$ are thoroughly reviewed, along with experimental results from GAMS, VES, Obelix, COMPASS, KEK, CLEO, Crystal Barrel, CLAS, and BNL. Theoretical lattice results on the gluelump spectrum, adiabatic potentials, heavy and light hybrids, and transition matrix elements are discussed. These are compared with bag, string, flux tube, and constituent gluon models. Strong and electromagnetic decay models are described and compared to lattice gauge theory results. We conclude that while good evidence for the existence of a light isovector exotic meson exists, its confirmation as a hybrid meson awaits discovery of its iso-partners. We also conclude that lattice gauge theory rules out a number of hybrid models and provides a reference to judge the success of others.
Furth, H.P.; Ludescher, C.
1984-08-01
The present paper briefly reviews the subject of tokamak-stellarator and pinch-stellarator hybrids, and points to two interesting new possibilities: compact-torus-stellarators and mirror-stellarators.
Yonit Kesten; Amir Pnueli; Joseph Sifakis; Sergio Yovine
1999-01-01
. Integration Graphs are a computational model developed inthe attempt to identify simple Hybrid Systems with decidable analysisproblems. We start with the class of constant slope hybrid systems(cshs), in which the right hand side of all differential equations is aninteger constant. We refer to continuous variables whose right hand sideconstants are always 1 as timers . All other continuous variables
Phylogenetic inference via sequential Monte Carlo.
Bouchard-Côté, Alexandre; Sankararaman, Sriram; Jordan, Michael I
2012-07-01
Bayesian inference provides an appealing general framework for phylogenetic analysis, able to incorporate a wide variety of modeling assumptions and to provide a coherent treatment of uncertainty. Existing computational approaches to bayesian inference based on Markov chain Monte Carlo (MCMC) have not, however, kept pace with the scale of the data analysis problems in phylogenetics, and this has hindered the adoption of bayesian methods. In this paper, we present an alternative to MCMC based on Sequential Monte Carlo (SMC). We develop an extension of classical SMC based on partially ordered sets and show how to apply this framework--which we refer to as PosetSMC--to phylogenetic analysis. We provide a theoretical treatment of PosetSMC and also present experimental evaluation of PosetSMC on both synthetic and real data. The empirical results demonstrate that PosetSMC is a very promising alternative to MCMC, providing up to two orders of magnitude faster convergence. We discuss other factors favorable to the adoption of PosetSMC in phylogenetics, including its ability to estimate marginal likelihoods, its ready implementability on parallel and distributed computing platforms, and the possibility of combining with MCMC in hybrid MCMC-SMC schemes. Software for PosetSMC is available at http://www.stat.ubc.ca/ bouchard/PosetSMC. PMID:22223445
Hybrid nanoscale inorganic cages
NASA Astrophysics Data System (ADS)
MacDonald, Janet E.; Bar Sadan, Maya; Houben, Lothar; Popov, Inna; Banin, Uri
2010-10-01
Cage structures exhibit inherent high symmetry and beauty, and both naturally occurring and synthetic molecular-scale cages have been discovered. Their characteristic high surface area and voids have led to their use as catalysts and catalyst supports, filtration media and gas storage materials. Nanometre-scale cage structures have also been synthesized, notably noble-metal cube-shaped cages prepared by galvanic displacement with promising applications in drug delivery and catalysis. Further functionality for nanostructures in general is provided by the concept of hybrid nanoparticles combining two disparate materials on the same system to achieve synergistic properties stemming from unusual material combinations. We report the integration of the two powerful concepts of cages and hybrid nanoparticles. A previously unknown edge growth mechanism has led to a new type of cage-structured hybrid metal-semiconductor nanoparticle; a ruthenium cage was grown selectively on the edges of a faceted copper(I) sulphide nanocrystal, contrary to the more commonly observed facet and island growth modes of other hybrids. The cage motif was extended by exploiting the open frame to achieve empty cages and cages containing other semiconductors. Such previously unknown nano-inorganic cage structures with variable cores and metal frames manifest new chemical, optical and electronic properties and demonstrate possibilities for uses in electrocatalysis.
Monte Carlo Generation of Bohmian Trajectories
T. M. Coffey; R. E. Wyatt; W. C. Schieve
2008-07-01
We report on a Monte Carlo method that generates one-dimensional trajectories for Bohm's formulation of quantum mechanics that doesn't involve differentiation or integration of any equations of motion. At each time, t=n\\delta t (n=1,2,3,...), N particle positions are randomly sampled from the quantum probability density. Trajectories are built from the sorted N sampled positions at each time. These trajectories become the exact Bohm solutions in the limits N->\\infty and \\delta t -> 0. Higher dimensional problems can be solved by this method for separable wave functions. Several examples are given, including the two-slit experiment.
NASA Astrophysics Data System (ADS)
Kim, Daeil; Yun, Junyeong; Lee, Geumbee; Ha, Jeong Sook
2014-09-01
We report on the on-chip fabrication of high performance flexible micro-supercapacitor (MSC) arrays with hybrid electrodes of multi-walled carbon nanotube (MWNT)/V2O5 nanowire (NW) composites and a solid electrolyte, which could power the SnO2 NW UV sensor integrated on the same flexible substrate. The patterned MSC using hybrid electrodes of MWNT/V2O5 NW composites with 10 vol% of V2O5 NWs exhibited excellent electrochemical performance with a high volume capacitance of 80 F cm-3 at a scan rate of 10 mV s-1 in a PVA-LiCl electrolyte and good cycle performance to maintain 82% of the capacitance after 10 000 cycles at a current density of 11.6 A cm-3. The patterned MSC also showed an excellent energy density of 6.8 mW h cm-3, comparable to that of a Li-thin film battery (1-10 mW h cm-3), and a power density of 80.8 W cm-3 comparable to that of state-of-the-art MSCs. In addition, the flexible MSC array on a PET substrate showed mechanical stability over bending with a bending radius down to 1.5 mm under both compressive and tensile stress. Even after 1000 bending cycles at a bending radius of 7 mm, 94% of the initial capacitance was maintained. Furthermore, we have shown the operation of a SnO2 NW UV sensor using such a fabricated MSC array integrated into the same circuit on the PET substrate.We report on the on-chip fabrication of high performance flexible micro-supercapacitor (MSC) arrays with hybrid electrodes of multi-walled carbon nanotube (MWNT)/V2O5 nanowire (NW) composites and a solid electrolyte, which could power the SnO2 NW UV sensor integrated on the same flexible substrate. The patterned MSC using hybrid electrodes of MWNT/V2O5 NW composites with 10 vol% of V2O5 NWs exhibited excellent electrochemical performance with a high volume capacitance of 80 F cm-3 at a scan rate of 10 mV s-1 in a PVA-LiCl electrolyte and good cycle performance to maintain 82% of the capacitance after 10 000 cycles at a current density of 11.6 A cm-3. The patterned MSC also showed an excellent energy density of 6.8 mW h cm-3, comparable to that of a Li-thin film battery (1-10 mW h cm-3), and a power density of 80.8 W cm-3 comparable to that of state-of-the-art MSCs. In addition, the flexible MSC array on a PET substrate showed mechanical stability over bending with a bending radius down to 1.5 mm under both compressive and tensile stress. Even after 1000 bending cycles at a bending radius of 7 mm, 94% of the initial capacitance was maintained. Furthermore, we have shown the operation of a SnO2 NW UV sensor using such a fabricated MSC array integrated into the same circuit on the PET substrate. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04138k
Smoothness and dimension reduction in Quasi-Monte Carlo methods
B. Moskowitz; R. E. Caflisch
1996-01-01
Monte Carlo integration using quasirandom sequences has theoretical error bounds of size O (N?1 logdN) in dimension d, as opposed to the error of size O (N?12) for random or pseudorandom sequences. In practice, however, this improved performance for quasirandom sequences is often not observed. The degradation of performance is due to discontinuity or lack of smoothness in the integrand
Kim, Daeil; Yun, Junyeong; Lee, Geumbee; Ha, Jeong Sook
2014-10-21
We report on the on-chip fabrication of high performance flexible micro-supercapacitor (MSC) arrays with hybrid electrodes of multi-walled carbon nanotube (MWNT)/V2O5 nanowire (NW) composites and a solid electrolyte, which could power the SnO2 NW UV sensor integrated on the same flexible substrate. The patterned MSC using hybrid electrodes of MWNT/V2O5 NW composites with 10 vol% of V2O5 NWs exhibited excellent electrochemical performance with a high volume capacitance of 80 F cm(-3) at a scan rate of 10 mV s(-1) in a PVA-LiCl electrolyte and good cycle performance to maintain 82% of the capacitance after 10,000 cycles at a current density of 11.6 A cm(-3). The patterned MSC also showed an excellent energy density of 6.8 mW h cm(-3), comparable to that of a Li-thin film battery (1-10 mW h cm(-3)), and a power density of 80.8 W cm(-3) comparable to that of state-of-the-art MSCs. In addition, the flexible MSC array on a PET substrate showed mechanical stability over bending with a bending radius down to 1.5 mm under both compressive and tensile stress. Even after 1000 bending cycles at a bending radius of 7 mm, 94% of the initial capacitance was maintained. Furthermore, we have shown the operation of a SnO2 NW UV sensor using such a fabricated MSC array integrated into the same circuit on the PET substrate. PMID:25184811
Monte Carlo and Quasi-Monte Carlo algorithms for the Barker-Ferry equation with low
Whitlock, Paula
Monte Carlo and Quasi-Monte Carlo algorithms for the Barker-Ferry equation with low complexity ? T. The quasi-Monte Carlo (QMC) solutions obtained by QRNs are compared with the Monte Carlo (MC) solutions) converges [3] and the solution can be evaluated by a MC estimator. 2 Monte Carlo and Quasi-Monte Carlo
Design of Monte Carlo Studies.
ERIC Educational Resources Information Center
Halperin, Silas
There are good reasons for the growing popularity of Monte Carlo procedures; but with increasing use comes increasing misuse. A variety of exact and approximate alternatives should be considered before one chooses to approach a problem with Monte Carlo methods. Once it has been decided that simulation is desirable, consideration should be given to…
Practical Markov Chain Monte Carlo
Charles J. Geyer
1992-01-01
Markov chain Monte Carlo using the Metropolis-Hastings algorithm is a general method for the simulation of stochastic processes having probability densities known up to a constant of proportionality. Despite recent advances in its theory, the practice has remained controversial. This article makes the case for basing all inference on one long run of the Markov chain and estimating the Monte
Marcus, Ryan C. [Los Alamos National Laboratory
2012-07-25
MCMini is a proof of concept that demonstrates the possibility for Monte Carlo neutron transport using OpenCL with a focus on performance. This implementation, written in C, shows that tracing particles and calculating reactions on a 3D mesh can be done in a highly scalable fashion. These results demonstrate a potential path forward for MCNP or other Monte Carlo codes.
Predictive Adaptation of Hybrid Monte Carlo with Bayesian Parametric Bandits
de Freitas, Nando
and advertising [20] and reinforcement learning [37]. They allow us to learn reward functions for actions. The new measures take the intended statistical use of the model, whose parameters are estimated by HMC, are widely used in statistics, physics and machine learning to sample from complex high- dimensional
Coghlan, J P; Aldred, P; Haralambidis, J; Niall, H D; Penschow, J D; Tregear, G W
1985-08-15
In this review we have used our own recent work as a flagship to illustrate the recent renaissance of interest in hybridization histochemistry. A trickle of papers followed the initial key excursion into the in situ labeling of tissue sections (48-50). Our own entry into this field started in 1978 and since then a confluence of important questions and technical advances has served to make hybridization histochemistry much more attractive as a research tool. Hybridization histochemistry is able to solve some problems for which there is no other suitable technique at this time. Hybridization histochemistry provides the location of anatomical sites of gene expression, and viral replication, with uniquely high specificity. We have taken 32P-labeled probes to what appears to be their limit of resolution, which is single cells in thin sections. While 32P has clear disadvantages, exposure time is relatively short and the use of fast-X-ray film to preview the results and estimate exposure time for emulsion has been turned to advantage. Our introduction (27) of the use of whole-mouse sections in hybridization histochemistry has great potential in hormonal, enzymatic, and growth factor gene expression and will no doubt prove of great use in developmental studies and examination of viral infection. The use of synthetic DNA (synthetic oligonucleotides) unshackles the technique from the need for an associated molecular biology laboratory and at once widens the horizon of application of the technique. Although hybridization histochemistry is a valuable research tool which will soon find a niche in many fields, in a short time it should become a key diagnostic aid. It may well become the method of preference for detection of the expression of oncogenes and other cancer-related genes and for viruses which for other reasons are difficult to detect. PMID:2416238
Zaw Zaw Oo; En-Xiao Liu; XingChang Wei; M. T. Y. Choon; Er-Ping Li; Yaojiang Zhang; Le-Wei Li
2007-01-01
The paper presents the development of a coupled scattering matrix method (SMM) with integral equation method for analyzing the power integrity (PI) of multilayered package structure with large number of power\\/ground vias. Analysis of the entire signal traces and the associated vias, connected between the power and ground, (named as P\\/G vias) is treated as analyzing the coupling between the
Hybrid control for the Pendubot
Tzyh-Jong Tarn; Mingjun Zhang; Fabio Celani
2000-01-01
New coordinate independent integrability conditions for second order nonholonomic systems, and hybrid control theorem for feedback stabilization of second order nonholonomic systems have been applied for control of the Pendubot, a test bed for dynamics and control of nonlinear systems. It is a 2-link planar robot with an actuator at the shoulder and no actuator at the elbow. Experimental results
Ozhikandathil, J.; Packirisamy, M.
2012-01-01
Integration of nano-materials in optical microfluidic devices facilitates the realization of miniaturized analytical systems with enhanced sensing abilities for biological and chemical substances. In this work, a novel method of integration of gold nano-islands in a silica-on-silicon-polydimethylsiloxane microfluidic device is reported. The device works based on the nano-enhanced evanescence technique achieved by interacting the evanescent tail of propagating wave with the gold nano-islands integrated on the core of the waveguide resulting in the modification of the propagating UV-visible spectrum. The biosensing ability of the device is investigated by finite-difference time-domain simulation with a simplified model of the device. The performance of the proposed device is demonstrated for the detection of recombinant growth hormone based on antibody-antigen interaction. PMID:24106526
Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Yan, Xiaojing; Dovichi, Norman J
2015-06-01
A sulfonate-silica hybrid strong cation-exchange (SCX) monolith was synthesized at the proximal end of a capillary zone electrophoresis column and used for on-line solid-phase extraction (SPE) sample preconcentration. Sample was prepared in an acidic buffer and deposited onto the SCX-SPE monolith and eluted using a basic buffer. Electrophoresis was performed in an acidic buffer. This combination of buffers results in formation of a dynamic pH junction, which allows use of relatively large elution buffer volume while maintaining peak efficiency and resolution. All experiments were performed with a 50µm ID capillary, a 1cm long SCX-SPE monolith, a 60cm long separation capillary, and a electrokinetically pumped nanospray interface. The volume of the capillary is 1.1µL. By loading 21µL of a 1×10(-7)M angiotensin II solution, an enrichment factor of 3000 compared to standard electrokinetic injection was achieved on this platform while retaining efficient electrophoretic performance (N=44,000 plates). The loading capacity of the sulfonate SCX hybrid monolith was determined to be ~15pmol by frontal analysis with 10(-5)M angiotensin II. The system was also applied to the analysis of a 10(-4)mg/mL bovine serum albumin tryptic digest; the protein coverage was 12% and 11 peptides were identified. Finally, by loading 5.5µL of a 10(-3)mg/mL E. coli digest, 109 proteins and 271 peptides were identified in a 20min separation; the median separation efficiency generated by these peptides was 25,000 theoretical plates. PMID:25863379
Hybrid fitness across time and habitats.
Arnold, Michael L; Martin, Noland H
2010-09-01
There has been considerable debate about the role of hybrids in the evolutionary process. One question has involved the relative fitness of hybrid versus non-hybrid genotypes. For some, the assumption of lower hybrid fitness continues to be integral to their concept of species and speciation. In contrast, numerous workers have suggested that hybrid genotypes might demonstrate higher relative fitness under various environmental settings. Of particular importance in deciding between these opposing hypotheses are long-term analyses coupling ecological and genetic information. Although currently rare, such analyses have provided a test of the fitness of hybrid genotypes across generations and habitats and their role in adaptation and speciation. Here we discuss examples of these analyses applied to viruses, prokaryotes, plants and Darwin's Finches. PMID:20598770
Monte Carlo Capabilities of the SCALE Code System
NASA Astrophysics Data System (ADS)
Rearden, B. T.; Petrie, L. M.; Peplow, D. E.; Bekar, K. B.; Wiarda, D.; Celik, C.; Perfetti, C. M.; Ibrahim, A. M.; Hart, S. W. D.; Dunn, M. E.
2014-06-01
SCALE is a widely used suite of tools for nuclear systems modeling and simulation that provides comprehensive, verified and validated, user-friendly capabilities for criticality safety, reactor physics, radiation shielding, and sensitivity and uncertainty analysis. For more than 30 years, regulators, licensees, and research institutions around the world have used SCALE for nuclear safety analysis and design. SCALE provides a "plug-and-play" framework that includes three deterministic and three Monte Carlo radiation transport solvers that can be selected based on the desired solution, including hybrid deterministic/Monte Carlo simulations. SCALE includes the latest nuclear data libraries for continuous-energy and multigroup radiation transport as well as activation, depletion, and decay calculations. SCALE's graphical user interfaces assist with accurate system modeling, visualization, and convenient access to desired results. SCALE 6.2, to be released in 2014, will provide several new capabilities and significant improvements in many existing features, especially with expanded continuous-energy Monte Carlo capabilities for criticality safety, shielding, depletion, and sensitivity and uncertainty analysis. An overview of the Monte Carlo capabilities of SCALE is provided here, with emphasis on new features for SCALE 6.2.
Harnessing graphical structure in Markov chain Monte Carlo learning
Stolorz, P.E. [California Inst. of Technology, Pasadena, CA (United States); Chew P.C. [Univ. of Pennsylvania, Philadelphia, PA (United States)
1996-12-31
The Monte Carlo method is recognized as a useful tool in learning and probabilistic inference methods common to many datamining problems. Generalized Hidden Markov Models and Bayes nets are especially popular applications. However, the presence of multiple modes in many relevant integrands and summands often renders the method slow and cumbersome. Recent mean field alternatives designed to speed things up have been inspired by experience gleaned from physics. The current work adopts an approach very similar to this in spirit, but focusses instead upon dynamic programming notions as a basis for producing systematic Monte Carlo improvements. The idea is to approximate a given model by a dynamic programming-style decomposition, which then forms a scaffold upon which to build successively more accurate Monte Carlo approximations. Dynamic programming ideas alone fail to account for non-local structure, while standard Monte Carlo methods essentially ignore all structure. However, suitably-crafted hybrids can successfully exploit the strengths of each method, resulting in algorithms that combine speed with accuracy. The approach relies on the presence of significant {open_quotes}local{close_quotes} information in the problem at hand. This turns out to be a plausible assumption for many important applications. Example calculations are presented, and the overall strengths and weaknesses of the approach are discussed.
Secondproofs Monte Carlo and Quasi-Monte Carlo Methods 2008
L'Ecuyer, Pierre
Pierre L'Ecuyer r Art B. Owen Editors Monte Carlo and Quasi-Monte Carlo Methods 2008 #12;Secondproofs Classification (2000): Primary 11K45, 65-06, 65C05, 65C10; Secondary 11K38, 65D18, 65D30, 65D32, 65R20, 91B28 Universiteit Leuven Luc Devroye, McGill University Henri Faure, CNRS Marseille Paul Glasserman, Columbia
Quantum Monte Carlo study of the protonated water dimer
Dagrada, Mario; Saitta, Antonino M; Sorella, Sandro; Mauri, Francesco
2013-01-01
We report an extensive theoretical study of the protonated water dimer (Zundel ion) by means of the highly correlated variational Monte Carlo and lattice regularized Monte Carlo approaches. This system represents the simplest model for proton transfer (PT) and a correct description of its properties is essential in order to understand the PT mechanism in more complex acqueous systems. Our Jastrow correlated AGP wave function ensures an accurate treatment of electron correlations. Exploiting the advantages of contracting the primitive basis set over atomic hybrid orbitals, we are able to limit dramatically the number of variational parameters with a systematic control on the numerical precision, crucial in order to simulate larger systems. We investigate energetics and geometrical properties of the Zundel ion as a function of the oxygen-oxygen distance, taken as reaction coordinate. In both cases, our QMC results are found in excellent agreement with coupled cluster CCSD(T) technique, the quantum chemistry "go...
Wormhole Hamiltonian Monte Carlo
Lan, Shiwei; Streets, Jeffrey; Shahbaba, Babak
2015-01-01
In machine learning and statistics, probabilistic inference involving multimodal distributions is quite difficult. This is especially true in high dimensional problems, where most existing algorithms cannot easily move from one mode to another. To address this issue, we propose a novel Bayesian inference approach based on Markov Chain Monte Carlo. Our method can effectively sample from multimodal distributions, especially when the dimension is high and the modes are isolated. To this end, it exploits and modifies the Riemannian geometric properties of the target distribution to create wormholes connecting modes in order to facilitate moving between them. Further, our proposed method uses the regeneration technique in order to adapt the algorithm by identifying new modes and updating the network of wormholes without affecting the stationary distribution. To find new modes, as opposed to redis-covering those previously identified, we employ a novel mode searching algorithm that explores a residual energy function obtained by subtracting an approximate Gaussian mixture density (based on previously discovered modes) from the target density function.
Optical Microsensors Integration Technologies for Biomedical Applications
NASA Astrophysics Data System (ADS)
Higurashi, Eiji; Sawada, Renshi; Suga, Tadatomo
This paper focuses on optical integration technology and its application in optical microsensors used in biomedical fields. The integration is based on the hybrid integration approach, achieving high performance, small size and weight, and lower cost. First, we describe the key technologies used in hybrid integration, namely passive alignment technology, low temperature bonding technology, and packaging technology for realizing advanced microsensors. Then, we describe an integrated laser Doppler flowmeter that can monitor blood flow in human skin.
NASA Astrophysics Data System (ADS)
Karioja, Pentti; Mäkinen, Jukka-Tapani; Keränen, Kimmo; Aikio, Janne; Alajoki, Teemu; Jaakola, Tuomo; Koponen, Matti; Keränen, Antti; Heikkinen, Mikko; Tuomikoski, Markus; Suhonen, Riikka; Hakalahti, Leena; Kopola, Pälvi; Hast, Jukka; Liedert, Ralf; Hiltunen, Jussi; Masuda, Noriyuki; Kemppainen, Antti; Rönkä, Kari; Korhonen, Raimo
2012-04-01
This paper presents research activities carried out at VTT Technical Research Centre of Finland in the field of hybrid integration of optics, electronics and mechanics. Main focus area in our research is the manufacturing of electronic modules and product structures with printed electronics, film-over-molding and polymer sheet lamination technologies and the goal is in the next generation of smart systems utilizing monolithic polymer packages. The combination of manufacturing technologies such as roll-to-roll -printing, injection molding and traditional component assembly is called Printed Hybrid Systems (PHS). Several demonstrator structures have been made, which show the potential of polymer packaging technology. One demonstrator example is a laminated structure with embedded LED chips. Element thickness is only 0.3mm and the flexible stack of foils can be bent in two directions after assembly process and was shaped curved using heat and pressure. The combination of printed flexible circuit boards and injection molding has also been demonstrated with several functional modules. The demonstrators illustrate the potential of origami electronics, which can be cut and folded to 3D shapes. It shows that several manufacturing process steps can be eliminated by Printed Hybrid Systems technology. The main benefits of this combination are small size, ruggedness and conformality. The devices are ideally suited for medical applications as the sensitive electronic components are well protected inside the plastic and the structures can be cleaned easily due to the fact that they have no joints or seams that can accumulate dirt or bacteria.
Geology of Maxwell Montes, Venus
NASA Technical Reports Server (NTRS)
Head, J. W.; Campbell, D. B.; Peterfreund, A. R.; Zisk, S. A.
1984-01-01
Maxwell Montes represent the most distinctive topography on the surface of Venus, rising some 11 km above mean planetary radius. The multiple data sets of the Pioneer missing and Earth based radar observations to characterize Maxwell Montes are analyzed. Maxwell Montes is a porkchop shaped feature located at the eastern end of Lakshmi Planum. The main massif trends about North 20 deg West for approximately 1000 km and the narrow handle extends several hundred km West South-West WSW from the north end of the main massif, descending down toward Lakshmi Planum. The main massif is rectilinear and approximately 500 km wide. The southern and northern edges of Maxwell Montes coincide with major topographic boundaries defining the edge of Ishtar Terra.
Jung Woon Lim; Sung Hwan Hwang; Seon Hoon Kim; Boo-Gyoun Kim; Byung Sup Rho
2007-01-01
We have developed a low cost 1.25 Gbps WDM bidirectional module using two integrated optical subassemblies which are composed of a planar lightwave circuit (PLC) platform and a silicon optical bench (SiOB) platform. The low cost module is achieved by employing a flip-chip bonding method with passive alignment using a Fabry-Perot laser diode (FP-LD) with a monitoring waveguide-photodiode (PD) on
Badapanda, Chandan
2013-01-01
The suppression subtractive hybridization (SSH) approach, a PCR based approach which amplifies differentially expressed cDNAs (complementary DNAs), while simultaneously suppressing amplification of common cDNAs, was employed to identify immuneinducible genes in insects. This technique has been used as a suitable tool for experimental identification of novel genes in eukaryotes as well as prokaryotes; whose genomes have been sequenced, or the species whose genomes have yet to be sequenced. In this article, I have proposed a method for in silico functional characterization of immune-inducible genes from insects. Apart from immune-inducible genes from insects, this method can be applied for the analysis of genes from other species, starting from bacteria to plants and animals. This article is provided with a background of SSH-based method taking specific examples from innate immune-inducible genes in insects, and subsequently a bioinformatics pipeline is proposed for functional characterization of newly sequenced genes. The proposed workflow presented here, can also be applied for any newly sequenced species generated from Next Generation Sequencing (NGS) platforms. PMID:23519487
Huang, Yukun; Chen, Rong; Wei, Jingbo; Pei, Xilong; Cao, Jing; Prakash Jayaraman, Prem; Ranjan, Rajiv
2014-01-01
JNI in the Android platform is often observed with low efficiency and high coding complexity. Although many researchers have investigated the JNI mechanism, few of them solve the efficiency and the complexity problems of JNI in the Android platform simultaneously. In this paper, a hybrid polylingual object (HPO) model is proposed to allow a CAR object being accessed as a Java object and as vice in the Dalvik virtual machine. It is an acceptable substitute for JNI to reuse the CAR-compliant components in Android applications in a seamless and efficient way. The metadata injection mechanism is designed to support the automatic mapping and reflection between CAR objects and Java objects. A prototype virtual machine, called HPO-Dalvik, is implemented by extending the Dalvik virtual machine to support the HPO model. Lifespan management, garbage collection, and data type transformation of HPO objects are also handled in the HPO-Dalvik virtual machine automatically. The experimental result shows that the HPO model outweighs the standard JNI in lower overhead on native side, better executing performance with no JNI bridging code being demanded. PMID:25110745
SPQR: a Monte Carlo reactor kinetics code. [LMFBR
Cramer, S.N.; Dodds, H.L.
1980-02-01
The SPQR Monte Carlo code has been developed to analyze fast reactor core accident problems where conventional methods are considered inadequate. The code is based on the adiabatic approximation of the quasi-static method. This initial version contains no automatic material motion or feedback. An existing Monte Carlo code is used to calculate the shape functions and the integral quantities needed in the kinetics module. Several sample problems have been devised and analyzed. Due to the large statistical uncertainty associated with the calculation of reactivity in accident simulations, the results, especially at later times, differ greatly from deterministic methods. It was also found that in large uncoupled systems, the Monte Carlo method has difficulty in handling asymmetric perturbations.
Vectorizing and macrotasking Monte Carlo neutral particle algorithms
Heifetz, D.B.
1987-04-01
Monte Carlo algorithms for computing neutral particle transport in plasmas have been vectorized and macrotasked. The techniques used are directly applicable to Monte Carlo calculations of neutron and photon transport, and Monte Carlo integration schemes in general. A highly vectorized code was achieved by calculating test flight trajectories in loops over arrays of flight data, isolating the conditional branches to as few a number of loops as possible. A number of solutions are discussed to the problem of gaps appearing in the arrays due to completed flights, which impede vectorization. A simple and effective implementation of macrotasking is achieved by dividing the calculation of the test flight profile among several processors. A tree of random numbers is used to ensure reproducible results. The additional memory required for each task may preclude using a larger number of tasks. In future machines, the limit of macrotasking may be possible, with each test flight, and split test flight, being a separate task.
A Quantum Monte Carlo Method at Fixed Energy
Edward Farhi; Jeffrey Goldstone; David Gosset; Harvey B. Meyer
2009-12-21
In this paper we explore new ways to study the zero temperature limit of quantum statistical mechanics using Quantum Monte Carlo simulations. We develop a Quantum Monte Carlo method in which one fixes the ground state energy as a parameter. The Hamiltonians we consider are of the form $H=H_{0}+\\lambda V$ with ground state energy E. For fixed $H_{0}$ and V, one can view E as a function of $\\lambda$ whereas we view $\\lambda$ as a function of E. We fix E and define a path integral Quantum Monte Carlo method in which a path makes no reference to the times (discrete or continuous) at which transitions occur between states. For fixed E we can determine $\\lambda(E)$ and other ground state properties of H.
Monte Carlo Simulation of Interacting Electron Models
Robinson, Robert W.
Monte Carlo Simulation of Interacting Electron Models by a New Determinant Approach by Mucheng discusses the calculation of determinants and Monte Carlo simulation of Hub- bard models by a new and a Monte Carlo summation algorithm to evaluate the relevant diagram determinant sums. Index words: Monte
Monte Carlo Methods for Inference and Learning
Hinton, Geoffrey E.
Monte Carlo Methods for Inference and Learning Guest Lecturer: Ryan Adams CSC 2535 http://www.cs.toronto.edu/~rpa #12;Overview Â·Monte Carlo basics Â·Rejection and Importance sampling Â·Markov chain Monte Carlo Â·Metropolis-Hastings and Gibbs sampling Â·Slice sampling Â·Hamiltonian Monte Carlo #12;Computing Expectations We
Bernhard Ketzer
2012-08-25
The SU(3)_flavor constituent quark model has been quite successful to explain the properties as well as the observed spectrum of mesons with pseudoscalar and vector quantum numbers. Many radial and orbital excitations of quark-antiquark systems predicted by the model, however, have not yet been observed experimentally or assigned unambiguously. In addition, a much richer spectrum of mesons is expected from QCD, in which quarks interact which each other through the exchange of colored self-interacting gluons. Owing to this particular structure of QCD, configurations are allowed in which an excited gluonic field contributes to the quantum numbers J^{PC} of the meson. States with a valence color-octet qqbar' pair neutralized in color by an excited gluon field are termed hybrids. The observation of such states, however, is difficult because they will mix with ordinary qqbar' states with the same quantum numbers, merely augmenting the observed spectrum for a given J^{PC}. Since the gluonic field may carry quantum numbers other than 0^{++}, however, this can give rise to states with "exotic" quantum numbers J^{PC}=0^{--}, 0^{+-}, 1^{-+}, 2^{+-},... The lowest-lying hybrid multiplet is expected to contain a state with exotic quantum numbers J^{PC}=1^{-+}. The identification of such a state is considered a "smoking gun" for the observation of non-qqbar mesons. The search for hybrid states has been a central goal of hadron spectroscopy in the last 20 years. Ongoing and upcoming high-statistics experiments are expected to shed new light on the existence of such states in nature. In this paper, theoretical predictions for masses and decay modes as well as recent experimental evidence for hybrid meson states and future experimental directions are discussed.
Quasi-Monte Carlo Sampling to improve the Efficiency of Monte Carlo EM
Jank, Wolfgang
Quasi-Monte Carlo Sampling to improve the Efficiency of Monte Carlo EM Wolfgang Jank Department@rhsmith.umd.edu November 17, 2003 Abstract In this paper we investigate an efficient implementation of the Monte Carlo EM al- gorithm based on Quasi-Monte Carlo sampling. The Monte Carlo EM algorithm is a stochastic version
Monte Carlo and Quasi-Monte Carlo for Art B. Owen
Owen, Art
Monte Carlo and Quasi-Monte Carlo for Statistics Art B. Owen Abstract This article reports Monte Carlo methods can be used. There was a special emphasis on areas where Quasi-Monte Carlo ideas This survey is aimed at exposing good problems in statistics to researchers in Quasi- Monte Carlo. It has
Density-of-states based Monte Carlo methods for simulation of biological systems
NASA Astrophysics Data System (ADS)
Rathore, Nitin; Knotts, Thomas A.; de Pablo, Juan J.
2004-03-01
We have developed density-of-states [1] based Monte Carlo techniques for simulation of biological molecules. Two such methods are discussed. The first, Configurational Temperature Density of States (CTDOS) [2], relies on computing the density of states of a peptide system from knowledge of its configurational temperature. The reciprocal of this intrinsic temperature, computed from instantaneous configurational information of the system, is integrated to arrive at the density of states. The method shows improved efficiency and accuracy over techniques that are based on histograms of random visits to distinct energy states. The second approach, Expanded Ensemble Density of States (EXEDOS), incorporates elements from both the random walk method and the expanded ensemble formalism. It is used in this work to study mechanical deformation of model peptides. Results are presented in the form of force-extension curves and the corresponding potentials of mean force. The application of this proposed technique is further generalized to other biological systems; results will be presented for ion transport through protein channels, base stacking in nucleic acids and hybridization of DNA strands. [1]. F. Wang and D. P. Landau, Phys. Rev. Lett., 86, 2050 (2001). [2]. N. Rathore, T. A. Knotts IV and J. J. de Pablo, Biophys. J., Dec. (2003).
Approximating Integrals Using Probability
ERIC Educational Resources Information Center
Maruszewski, Richard F., Jr.; Caudle, Kyle A.
2005-01-01
As part of a discussion on Monte Carlo methods, which outlines how to use probability expectations to approximate the value of a definite integral. The purpose of this paper is to elaborate on this technique and then to show several examples using visual basic as a programming tool. It is an interesting method because it combines two branches of…
Monte Carlo simulation study of droplet nucleation
NASA Astrophysics Data System (ADS)
Neimark, Alexander V.; Vishnyakov, Aleksey
2005-05-01
A new rigorous Monte Carlo simulation approach is employed to study nucleation barriers for droplets in Lennard-Jones fluid. Using the gauge cell method we generate the excess isotherm of critical clusters in the size range from two to six molecular diameters. The ghost field method is employed to compute the cluster free energy and the nucleation barrier with desired precision of (1-2)kT. Based on quantitative results obtained by Monte Carlo simulations, we access the limits of applicability of the capillarity approximation of the classical nucleation theory and the Tolman equation. We show that the capillarity approximation corrected for vapor nonideality and liquid compressibility provides a reasonable assessment for the size of critical clusters in Lennard-Jones fluid; however, its accuracy is not sufficient to predict the nucleation barriers for making practical estimates of the rate of nucleation. The established dependence of the droplet surface tension on the droplet size cannot be approximated by the Tolman equation for small droplets of radius less than four molecular diameters. We confirm the conclusion of ten Wolde and Frenkel [J. Chem. Phys. 109, 9901 (1998)] that integration of the normal component of the Irving-Kirkwood pressure tensor severely underestimates the nucleation barriers for small clusters.
Genomic Networks of Hybrid Sterility
Turner, Leslie M.; White, Michael A.; Tautz, Diethard; Payseur, Bret A.
2014-01-01
Hybrid dysfunction, a common feature of reproductive barriers between species, is often caused by negative epistasis between loci (“Dobzhansky-Muller incompatibilities”). The nature and complexity of hybrid incompatibilities remain poorly understood because identifying interacting loci that affect complex phenotypes is difficult. With subspecies in the early stages of speciation, an array of genetic tools, and detailed knowledge of reproductive biology, house mice (Mus musculus) provide a model system for dissecting hybrid incompatibilities. Male hybrids between M. musculus subspecies often show reduced fertility. Previous studies identified loci and several X chromosome-autosome interactions that contribute to sterility. To characterize the genetic basis of hybrid sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven ‘hotspots,’ seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL—but not cis eQTL—were substantially lower when mapping was restricted to a ‘fertile’ subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility. The integrated mapping approach we employed is applicable in a broad range of organisms and we advocate for widespread adoption of a network-centered approach in speciation genetics. PMID:24586194
NASA Astrophysics Data System (ADS)
Congote, J.; Moreno, A.; Kabongo, L.; Pérez, J.-L.; San-José, R.; Ruiz, O.
2012-10-01
City models visualisation, buildings, structures and volumetric information, is an important task in Computer Graphics and Urban Planning. The different formats and data sources involved in the visualisation make the development of applications a big challenge. We present a homogeneous web visualisation framework using X3DOM and MEDX3DOM for the visualisation of these urban objects. We present an integration of different declarative data sources, enabling the utilization of advanced visualisation algorithms to render the models. It has been tested with a city model composed of buildings from the Madrid University Campus, some volumetric datasets coming from Air Quality Models and 2D layers wind datasets. Results show that the visualisation of all the urban models can be performed in real time on the Web. An HTML5 web interface is presented to the users, enabling real time modifications of visualisation parameters.
Xiao, Fang-Xing; Hung, Sung-Fu; Tao, Hua Bing; Miao, Jianwei; Yang, Hong Bin; Liu, Bin
2014-12-21
Hierarchically ordered ZnO nanorods (NRs) decorated nanoporous-layer-covered TiO2 nanotube array (ZnO NRs/NP-TNTAs) nanocomposites have been prepared by an efficient, two-step anodization route combined with an electrochemical deposition strategy, by which monodispersed one-dimensional (1D) ZnO NRs were uniformly grown on the framework of NP-TNTAs. The crystal phases, morphologies, optical properties, photocatalytic as well as photoelectrocatalytic performances of the well-defined ZnO NRs/NP-TNTAs heterostructures were systematically explored to clarify the structure-property correlation. It was found that the ZnO NRs/NP-TNTAs heterostructure exhibits significantly enhanced photocatalytic and photoelectrocatalytic performances, along with favorable photostability toward degradation of organic pollutants under UV light irradiation, as compared to the single component counterparts. The remarkably enhanced photoactivity of ZnO NRs/NP-TNTAs heterostructure is ascribed to the intimate interfacial integration between ZnO NRs and NP-TNTAs substrate imparted by the unique spatially branched hierarchical structure, thereby contributing to the efficient transfer and separation of photogenerated electron-hole charge carriers. Moreover, the specific active species during the photocatalytic process was unambiguously determined and photocatalytic mechanism was tentatively presented. It is anticipated that our work could provide new insights for the construction of various hierarchical 1D-1D hybrid nanocomposites for extensive photocatalytic applications. PMID:25363649
A Residual Monte Carlo Method for Spatially Discrete, Angularly Continuous Radiation Transport
Wollaeger, Ryan T. [Los Alamos National Laboratory; Densmore, Jeffery D. [Los Alamos National Laboratory
2012-06-19
Residual Monte Carlo provides exponential convergence of statistical error with respect to the number of particle histories. In the past, residual Monte Carlo has been applied to a variety of angularly discrete radiation-transport problems. Here, we apply residual Monte Carlo to spatially discrete, angularly continuous transport. By maintaining angular continuity, our method avoids the deficiencies of angular discretizations, such as ray effects. For planar geometry and step differencing, we use the corresponding integral transport equation to calculate an angularly independent residual from the scalar flux in each stage of residual Monte Carlo. We then demonstrate that the resulting residual Monte Carlo method does indeed converge exponentially to within machine precision of the exact step differenced solution.
NASA Astrophysics Data System (ADS)
Show, Bijay Kumar; Mondal, Dipak Kumar; Maity, Joydeep
2014-12-01
In this research work, the dry sliding wear behavior of 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite was investigated at low sliding speed (1 m/s) against a hardened EN 31 disk at different loads. In general, the wear mechanism involved adhesion (along with associated subsurface cracking and delamination) and microcutting abrasion at lower load. While at higher load, abrasive wear involving microcutting and microploughing along with adherent oxide formation was observed. The overall wear rate increased with increasing normal load. The massive particle clusters as well as individual reinforcement particles were found to stand tall to resist abrasive wear. Besides, at higher load, the generation of adherent nodular tribo-oxide through nucleation and epitaxial growth on existing Al2O3 particles lowered down the wear rate. Accordingly, at any normal load, 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite exhibited superior wear resistance (lower overall wear rate) than the reported wear resistance of monolithic 6351 Al alloy.
HOPSPACK: Hybrid Optimization Parallel Search Package.
Gray, Genetha A.; Kolda, Tamara G.; Griffin, Joshua; Taddy, Matt; Martinez-Canales, Monica
2008-12-01
In this paper, we describe the technical details of HOPSPACK (Hybrid Optimization Parallel SearchPackage), a new software platform which facilitates combining multiple optimization routines into asingle, tightly-coupled, hybrid algorithm that supports parallel function evaluations. The frameworkis designed such that existing optimization source code can be easily incorporated with minimalcode modification. By maintaining the integrity of each individual solver, the strengths and codesophistication of the original optimization package are retained and exploited.4
Bayesian Phylogenetic Inference Using DNA Sequences: A Markov Chain Monte Carlo Method
Ziheng Yang; Bruce Rannala
An improved Bayesian method is presented for estimating phylogenetic trees using DNA sequence data. The birth- death process with species sampling is used to specify the prior distribution of phylogenies and ancestral speciation times, and the posterior probabilities of phylogenies are used to estimate the maximum posterior probability (MAP) tree. Monte Carlo integration is used to integrate over the ancestral
THE CONVERGENCE OF CHAOTIC INTEGRALS
Oliver Bauer; Ronnie Mainieri
1995-05-12
We review the convergence of chaotic integrals computed by Monte Carlo simulation, the trace method, dynamical zeta function, and Fredholm determinant on a simple one-dimensional example: the parabola repeller. There is a dramatic difference in convergence between these approaches. The convergence of the Monte Carlo method follows an inverse power law, whereas the trace method and dynamical zeta function converge exponentially, and the Fredholm determinant converges faster than any exponential.
Tests for Unit Roots: A Monte Carlo Investigation
G. William Schwert
1989-01-01
Recent work by Said and Dickey (1984, 1985), Phillips (1987), and Phillips and Perron (1988) examines tests for unit roots in the autoregressive part of mixed autoregressive integrated moving average models (tests for stationary). Monte Carlo experiments show that these unit-root tests have different finite-sample distributions from the unit-root tests developed by Fuller (1976) and Dickey and Fuller (1979, 1981)
Monte Carlo Methods and Applications for the Nuclear Shell Model
Dean, D.J.; White, J.A.
1998-08-10
The shell-model Monte Carlo (SMMC) technique transforms the traditional nuclear shell-model problem into a path-integral over auxiliary fields. We describe below the method and its applications to four physics issues: calculations of sd-pf-shell nuclei, a discussion of electron-capture rates in pf-shell nuclei, exploration of pairing correlations in unstable nuclei, and level densities in rare earth systems.
NASA Astrophysics Data System (ADS)
Caragiulo, P.; Dragone, A.; Markovic, B.; Herbst, R.; Nishimura, K.; Reese, B.; Herrmann, S.; Hart, P.; Blaj, G.; Segal, J.; Tomada, A.; Hasi, J.; Carini, G.; Kenney, C.; Haller, G.
2014-09-01
ePix100 is the first variant of a novel class of integrating pixel ASICs architectures optimized for the processing of signals in second generation LINAC Coherent Light Source (LCLS) X-Ray cameras. ePix100 is optimized for ultra-low noise application requiring high spatial resolution. ePix ASICs are based on a common platform composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog to digital converters per column. The ePix100 variant has 50?mx50?m pixels arranged in a 352x384 matrix, a resolution of 50e- r.m.s. and a signal range of 35fC (100 photons at 8keV). In its final version it will be able to sustain a frame rate of 1kHz. A first prototype has been fabricated and characterized and the measurement results are reported here.
Hybrid Hybridization at the Electron Microscope Level\\
NANCY J. HUTCHISON; PENNINA R. LANGER-SAFER; DAVID C. WARD; BARBARA A. HAMKALO
In situ hybridization has become a standard method for localizing DNA or RNA sequences in cytological preparations. We developed two methods to extend this technique to the transmission electron microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope in situ hybridization.
Design and analysis of continuous hybrid differentiator
Wang, Xinhua
2011-01-01
In this paper, a continuous hybrid differentiator is presented based on a strong Lyapunov function. The differentiator design can not only reduce sufficiently chattering phenomenon of derivative estimation by introducing a perturbation parameter, but also the dynamical performances are improved by adding linear correction terms to the nonlinear ones. Moreover, strong robustness ability is obtained by integrating sliding mode items and the linear filter. Frequency analysis is applied to compare the hybrid continuous differentiator with sliding mode differentiator. The merits of the continuous hybrid differentiator include the excellent dynamical performances, restraining noises sufficiently, and avoiding the chattering phenomenon.
Hybrid Power Management Program Continued
NASA Technical Reports Server (NTRS)
Eichenberg, Dennis J.
2002-01-01
Hybrid Power Management (HPM) is the innovative integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications. The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The advanced power devices include ultracapacitors and photovoltaics. HPM has extremely wide potential with applications including power-generation, transportation, biotechnology, and space power systems. It may significantly alleviate global energy concerns, improve the environment, and stimulate the economy.
Small hybrid solar power system
M. Kane; D. Larrain; D. Favrat; Y. Allani
2003-01-01
This paper introduces a novel concept of mini-hybrid solar power plant integrating a field of solar concentrators, two superposed Organic Rankine Cycles (ORC) and a (bio-)Diesel engine. The Organic Rankine Cycles include hermetic scroll expander-generators11The word expander is often used to characterize units recovering the expansion energy of a gas, in particular when based on a volumetric machine. The word
2013-01-01
Background Psychosocial problems are more prevalent among patients with chronic diseases than among the general population. They may lead to a downward spiral of poor adherence, deterioration of the condition and decline in daily functioning. In addition to medical management, systematic attention to emotional and role management tasks during routine chronic care seems mandatory. We intend to integrate an existing nurse-led minimal psychological intervention to support patients’ self-management, which appeared to be effective and cost-effective, in routine care by primary care nurses, so we adjusted it to fit the host setting. The resulting Self-Management Support (SMS) programme involves early detection of patients with emotional distress and problems of daily functioning, as well as self-management support through problem solving and reattribution techniques. Strategies to embed SMS in daily practice include training and booster sessions for practice nurses as well as organisational and financial arrangements. This study aims to simultaneously evaluate the implementation process and effects of SMS in routine care, using a hybrid effectiveness–implementation design. Methods/Design Registration data, questionnaires and interviews will be used to explore the facilitators, barriers and costs regarding successful implementation of SMS. The effects of SMS will be evaluated in a pragmatic cluster-randomised controlled trial with a baseline measurement and follow-up measurements after 4 and 12 months. The population will consist of 46 practice nurses and their type 2 diabetes patients (N?=?460; 10 per practice nurse). The practice nurses will be randomly assigned to the intervention or control group. Practice nurses of the intervention group will receive SMS training. Patients for the intervention and control groups will be recruited by a researcher-led self-administered screening procedure to decide which patients of those scheduled for routine consultation are likely to be detected by the practice nurses as eligible for the self-management support. Primary outcome measure is patients’ daily functioning. Secondary measures include emotional well-being, participation, autonomy and control over the disease. Discussion Our hybrid study design is complicated by the detection method used by the practice nurses. This method is an implementation issue in itself that has consequences for the realisation and power of the effect evaluation. Trial registration Current Controlled Trials, NTR2764 PMID:23758974
Semi-stochastic full configuration interaction quantum Monte Carlo
NASA Astrophysics Data System (ADS)
Holmes, Adam; Petruzielo, Frank; Khadilkar, Mihir; Changlani, Hitesh; Nightingale, M. P.; Umrigar, C. J.
2012-02-01
In the recently proposed full configuration interaction quantum Monte Carlo (FCIQMC) [1,2], the ground state is projected out stochastically, using a population of walkers each of which represents a basis state in the Hilbert space spanned by Slater determinants. The infamous fermion sign problem manifests itself in the fact that walkers of either sign can be spawned on a given determinant. We propose an improvement on this method in the form of a hybrid stochastic/deterministic technique, which we expect will improve the efficiency of the algorithm by ameliorating the sign problem. We test the method on atoms and molecules, e.g., carbon, carbon dimer, N2 molecule, and stretched N2. [4pt] [1] Fermion Monte Carlo without fixed nodes: a Game of Life, death and annihilation in Slater Determinant space. George Booth, Alex Thom, Ali Alavi. J Chem Phys 131, 050106, (2009).[0pt] [2] Survival of the fittest: Accelerating convergence in full configuration-interaction quantum Monte Carlo. Deidre Cleland, George Booth, and Ali Alavi. J Chem Phys 132, 041103 (2010).
Mission Analysis, Operations, and Navigation Toolkit Environment (Monte) Version 040
NASA Technical Reports Server (NTRS)
Sunseri, Richard F.; Wu, Hsi-Cheng; Evans, Scott E.; Evans, James R.; Drain, Theodore R.; Guevara, Michelle M.
2012-01-01
Monte is a software set designed for use in mission design and spacecraft navigation operations. The system can process measurement data, design optimal trajectories and maneuvers, and do orbit determination, all in one application. For the first time, a single software set can be used for mission design and navigation operations. This eliminates problems due to different models and fidelities used in legacy mission design and navigation software. The unique features of Monte 040 include a blowdown thruster model for GRAIL (Gravity Recovery and Interior Laboratory) with associated pressure models, as well as an updated, optimalsearch capability (COSMIC) that facilitated mission design for ARTEMIS. Existing legacy software lacked the capabilities necessary for these two missions. There is also a mean orbital element propagator and an osculating to mean element converter that allows long-term orbital stability analysis for the first time in compiled code. The optimized trajectory search tool COSMIC allows users to place constraints and controls on their searches without any restrictions. Constraints may be user-defined and depend on trajectory information either forward or backwards in time. In addition, a long-term orbit stability analysis tool (morbiter) existed previously as a set of scripts on top of Monte. Monte is becoming the primary tool for navigation operations, a core competency at JPL. The mission design capabilities in Monte are becoming mature enough for use in project proposals as well as post-phase A mission design. Monte has three distinct advantages over existing software. First, it is being developed in a modern paradigm: object- oriented C++ and Python. Second, the software has been developed as a toolkit, which allows users to customize their own applications and allows the development team to implement requirements quickly, efficiently, and with minimal bugs. Finally, the software is managed in accordance with the CMMI (Capability Maturity Model Integration), where it has been ap praised at maturity level 3.
EDDE Monte Carlo event generator
V. A. Petrov; R. A. Ryutin; A. E. Sobol; J. -P. Guillaud
2005-09-26
EDDE is a Monte Carlo event generator, under construction, for different Exclusive Double Diffractive Events. The program is based on the extended Regge-eikonal approach for "soft" processes. Standard Model and its extensions are used for "hard" fusion processes. An interface to PYTHIA, CMSJET and CMKIN is provided.
Michael H. Seymour
2010-08-17
I review the status of the general-purpose Monte Carlo event generators for the LHC, with emphasis on areas of recent physics developments. There has been great progress, especially in multi-jet simulation, but I mention some question marks that have recently arisen.
NSDL National Science Digital Library
2008-12-30
This is the description and instructions for the Monte Carlo Estimation of Pi applet. It is a simulation of throwing darts at a figure of a circle inscribed in a square. It shows the relationship between the geometry of the figure and the statistical outcome of throwing the darts.
Synchronous Parallel Kinetic Monte Carlo
Mart?nez, E; Marian, J; Kalos, M H
2006-12-14
A novel parallel kinetic Monte Carlo (kMC) algorithm formulated on the basis of perfect time synchronicity is presented. The algorithm provides an exact generalization of any standard serial kMC model and is trivially implemented in parallel architectures. We demonstrate the mathematical validity and parallel performance of the method by solving several well-understood problems in diffusion.
Applications of Monte Carlo Methods in Calculus.
ERIC Educational Resources Information Center
Gordon, Sheldon P.; Gordon, Florence S.
1990-01-01
Discusses the application of probabilistic ideas, especially Monte Carlo simulation, to calculus. Describes some applications using the Monte Carlo method: Riemann sums; maximizing and minimizing a function; mean value theorems; and testing conjectures. (YP)
Suitable Candidates for Monte Carlo Solutions.
ERIC Educational Resources Information Center
Lewis, Jerome L.
1998-01-01
Discusses Monte Carlo methods, powerful and useful techniques that rely on random numbers to solve deterministic problems whose solutions may be too difficult to obtain using conventional mathematics. Reviews two excellent candidates for the application of Monte Carlo methods. (ASK)
Paris-Sud XI, Université de
is a general approach for control of a switching-based hybrid system (HS). This class of HS includes or predictive control, where the inverter is not taken into account by the controller, hybrid control integrates]. In this paper, a hybrid-control technique is proposed. It is a general approach for control of a class of hybrid
Formula Hybrid International Competition
Carver, Jeffrey C.
of the hybrid gasoline engine, there are more components to a hybrid drivetrain, including the electric motor, and computerized control systems. But the greatest obstacle of all was that hybrid cars could not meet newlyFormula Hybrid International Competition May 4, 5, 6, 2009 #12;09 annual third We are thrilled
Liskiewicz, Maciej
Virginia Corn Hybrid and Management Trials 2007 Virginia Corn & Small Grain Management #12;VIRGINIA CORN HYBRID AND MANAGEMENT TRIALS IN 2007 Coordinators of Virginia Corn Hybrid Trials in 2007 Wade Farm, Virginia Tech Companies Participating in the 2007 Corn Hybrid Trials Company Brand Address
Liskiewicz, Maciej
Virginia Corn Hybrid Management and Trials 2006 Virginia Corn & Small Grain Management #12;#12;Virginia Corn Hybrid and Management Trials 2006 Coordinators of Virginia Corn Hybrid Trials in 2006 Wade Farm, Virginia Tech Companies Participating in the 2006 Corn Hybrid Trials Company Brand Address
Efficient pseudo-random number generation for monte-carlo simulations using graphic processors
NASA Astrophysics Data System (ADS)
Mohanty, Siddhant; Mohanty, A. K.; Carminati, F.
2012-06-01
A hybrid approach based on the combination of three Tausworthe generators and one linear congruential generator for pseudo random number generation for GPU programing as suggested in NVIDIA-CUDA library has been used for MONTE-CARLO sampling. On each GPU thread, a random seed is generated on fly in a simple way using the quick and dirty algorithm where mod operation is not performed explicitly due to unsigned integer overflow. Using this hybrid generator, multivariate correlated sampling based on alias technique has been carried out using both CUDA and OpenCL languages.
Hybrid community energy systems.
Jody, B. J.; Daniels, E. J.; Karvelas, D. E.; Energy Systems
2000-01-01
The availability of efficient, economical, and reliable energy supplies can help attract industry and commercial businesses to a municipality or a region. Efficient use of energy can also improve the air quality and reduce pollution. Therefore, municipalities should explore and encourage the development and implementation of efficient energy systems. Integrated hybrid energy systems can be designed to meet the total energy requirements of large and small communities. These systems can yield significant energy and cost savings when compared with independent systems serving individual units or when compared with the conventional practice of buying power from a utility and producing thermal energy on-site. To maximize energy and cost savings, the design engineer should look beyond the conventional when designing such systems.
Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group
Towards Monte Carlo Simulations on Large Nuclei Â· August 2014 Towards Monte Carlo Simulations published method to compute properties on neutron matter using variational Monte Carlo simulations published a method of performing variational Monte Carlo calculations on neutron matter comprised of up
Monte Carlo Methods in Statistics Christian Robert
Boyer, Edmond
Monte Carlo Methods in Statistics Christian Robert UniversitÂ´e Paris Dauphine and CREST, INSEE September 2, 2009 Monte Carlo methods are now an essential part of the statistician's toolbox, to the point! We recall in this note some of the advances made in the design of Monte Carlo techniques towards
MONTE CARLO METHOD AND SENSITIVITY ESTIMATIONS
Dufresne, Jean-Louis
MONTE CARLO METHOD AND SENSITIVITY ESTIMATIONS A. de Lataillade a;#3; , S. Blanco b , Y. Clergent b on a formal basis and simple radiative transfer examples are used for illustration. Key words: Monte Carlo submitted to Elsevier Science 18 February 2002 #12; 1 Introduction Monte Carlo methods are commonly used
Monte Carlo Simulations of Model Nonionic Surfactants
Monte Carlo Simulations of Model Nonionic Surfactants A.P. Chatterjee and A.Z. Panagiotopoulos was studied by histogram reweight- ing grand canonical Monte Carlo simulations. Two di erent sets of site volume fractions using lattice Monte Carlo simulations performed in the canonical constant NV T ensemble
A Monte Carlo Study of Titrating Polyelectrolytes
Peterson, Carsten
A Monte Carlo Study of Titrating Polyelectrolytes Magnus Ullner y and Bo JÂ¨onsson z Physical, Sweden Journal of Chemical Physics 104, 3048Â3057 (1996) Monte Carlo simulations have been used to study of the polymer more difficult and biases the conformations towards more extended structures. In the Monte Carlo
A Monte Carlo Study of Titrating Polyelectrolytes
Peterson, Carsten
A Monte Carlo Study of Titrating Polyelectrolytes Magnus Ullnery and Bo Jonssonz Physical Chemistry Journal of Chemical Physics 104, 3048-3057 (1996) Monte Carlo simulations have been used to study three di the conformations towards more extended structures. In the Monte Carlo simulations presented here, focus
Monte Carlo Simulation for Perusal and Practice.
ERIC Educational Resources Information Center
Brooks, Gordon P.; Barcikowski, Robert S.; Robey, Randall R.
The meaningful investigation of many problems in statistics can be solved through Monte Carlo methods. Monte Carlo studies can help solve problems that are mathematically intractable through the analysis of random samples from populations whose characteristics are known to the researcher. Using Monte Carlo simulation, the values of a statistic are…
NSDL National Science Digital Library
Layton, Julia
Hybrid cars and other vehicles have been around for many years. This site treats the reader to information concerning a variety of different forms of alternative energy vehicles including the gasoline-electric hybrid car, diesel-electric hybrids and the differences between the series and parallel hybrid vehicles. It also offers a table of contents for additional information dealing with nearly everything you ever wanted to know about hybrid vehicles.
Bockholt, A. J.; Collier, J. W.
1960-01-01
NOVEMBER 196 Corn C Hybrids . . k3;;.:- " for Texas LIBRARY W~MENTS DIVISIOI( A & M COLLEGE OF TD(&# STATION, TUAS SUMMARY 1 Corn hybrids were planted on 85 percent of the Texas corn acreage in 1959. Most of this ac was devoted...-year testing period. p rd Considering yield and other desirable characteristics, five yellow hybrids and three white hybrid recommended for corn production in Texas. A brief description is given of these hybrids with theii m).. a of adaptation. K...
NASA Astrophysics Data System (ADS)
Xiao, Fang-Xing; Hung, Sung-Fu; Tao, Hua Bing; Miao, Jianwei; Yang, Hong Bin; Liu, Bin
2014-11-01
Hierarchically ordered ZnO nanorods (NRs) decorated nanoporous-layer-covered TiO2 nanotube array (ZnO NRs/NP-TNTAs) nanocomposites have been prepared by an efficient, two-step anodization route combined with an electrochemical deposition strategy, by which monodispersed one-dimensional (1D) ZnO NRs were uniformly grown on the framework of NP-TNTAs. The crystal phases, morphologies, optical properties, photocatalytic as well as photoelectrocatalytic performances of the well-defined ZnO NRs/NP-TNTAs heterostructures were systematically explored to clarify the structure-property correlation. It was found that the ZnO NRs/NP-TNTAs heterostructure exhibits significantly enhanced photocatalytic and photoelectrocatalytic performances, along with favorable photostability toward degradation of organic pollutants under UV light irradiation, as compared to the single component counterparts. The remarkably enhanced photoactivity of ZnO NRs/NP-TNTAs heterostructure is ascribed to the intimate interfacial integration between ZnO NRs and NP-TNTAs substrate imparted by the unique spatially branched hierarchical structure, thereby contributing to the efficient transfer and separation of photogenerated electron-hole charge carriers. Moreover, the specific active species during the photocatalytic process was unambiguously determined and photocatalytic mechanism was tentatively presented. It is anticipated that our work could provide new insights for the construction of various hierarchical 1D-1D hybrid nanocomposites for extensive photocatalytic applications.Hierarchically ordered ZnO nanorods (NRs) decorated nanoporous-layer-covered TiO2 nanotube array (ZnO NRs/NP-TNTAs) nanocomposites have been prepared by an efficient, two-step anodization route combined with an electrochemical deposition strategy, by which monodispersed one-dimensional (1D) ZnO NRs were uniformly grown on the framework of NP-TNTAs. The crystal phases, morphologies, optical properties, photocatalytic as well as photoelectrocatalytic performances of the well-defined ZnO NRs/NP-TNTAs heterostructures were systematically explored to clarify the structure-property correlation. It was found that the ZnO NRs/NP-TNTAs heterostructure exhibits significantly enhanced photocatalytic and photoelectrocatalytic performances, along with favorable photostability toward degradation of organic pollutants under UV light irradiation, as compared to the single component counterparts. The remarkably enhanced photoactivity of ZnO NRs/NP-TNTAs heterostructure is ascribed to the intimate interfacial integration between ZnO NRs and NP-TNTAs substrate imparted by the unique spatially branched hierarchical structure, thereby contributing to the efficient transfer and separation of photogenerated electron-hole charge carriers. Moreover, the specific active species during the photocatalytic process was unambiguously determined and photocatalytic mechanism was tentatively presented. It is anticipated that our work could provide new insights for the construction of various hierarchical 1D-1D hybrid nanocomposites for extensive photocatalytic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04886e
Monte Carlo calculation of monitor unit for electron arc therapy
Chow, James C. L.; Jiang Runqing [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, Ontario M5G 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada) and Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Department of Medical Physics, Grand River Regional Cancer Center, Kitchener, Ontario N2G 1G3 (Canada)
2010-04-15
Purpose: Monitor unit (MU) calculations for electron arc therapy were carried out using Monte Carlo simulations and verified by measurements. Variations in the dwell factor (DF), source-to-surface distance (SSD), and treatment arc angle ({alpha}) were studied. Moreover, the possibility of measuring the DF, which requires gantry rotation, using a solid water rectangular, instead of cylindrical, phantom was investigated. Methods: A phase space file based on the 9 MeV electron beam with rectangular cutout (physical size=2.6x21 cm{sup 2}) attached to the block tray holder of a Varian 21 EX linear accelerator (linac) was generated using the EGSnrc-based Monte Carlo code and verified by measurement. The relative output factor (ROF), SSD offset, and DF, needed in the MU calculation, were determined using measurements and Monte Carlo simulations. An ionization chamber, a radiographic film, a solid water rectangular phantom, and a cylindrical phantom made of polystyrene were used in dosimetry measurements. Results: Percentage deviations of ROF, SSD offset, and DF between measured and Monte Carlo results were 1.2%, 0.18%, and 1.5%, respectively. It was found that the DF decreased with an increase in {alpha}, and such a decrease in DF was more significant in the {alpha} range of 0 deg. - 60 deg. than 60 deg. - 120 deg. Moreover, for a fixed {alpha}, the DF increased with an increase in SSD. Comparing the DF determined using the rectangular and cylindrical phantom through measurements and Monte Carlo simulations, it was found that the DF determined by the rectangular phantom agreed well with that by the cylindrical one within {+-}1.2%. It shows that a simple setup of a solid water rectangular phantom was sufficient to replace the cylindrical phantom using our specific cutout to determine the DF associated with the electron arc. Conclusions: By verifying using dosimetry measurements, Monte Carlo simulations proved to be an alternative way to perform MU calculations effectively for electron arc therapy. Since Monte Carlo simulations can generate a precalculated database of ROF, SSD offset, and DF for the MU calculation, with a reduction in human effort and linac beam-on time, it is recommended that Monte Carlo simulations be partially or completely integrated into the commissioning of electron arc therapy.