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1

Graduiertenschule Hybrid Monte Carlo  

E-print Network

Graduiertenschule Hybrid Monte Carlo SS 2005 Heermann - Universit篓at Heidelberg Seite 1 #12;Graduiertenschule 路 In conventional Monte-Carlo (MC) calculations of condensed matter systems, such as an N probability distribution, unlike Monte-Carlo calculations. 路 The Hybrid Monte-Carlo (HMC) method combines

Heermann, Dieter W.

2

Extra Chance Generalized Hybrid Monte Carlo  

NASA Astrophysics Data System (ADS)

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.

Campos, C閐ric M.; Sanz-Serna, J. M.

2015-01-01

3

Hybrid Silicon Integration R. Jones et al. Hybrid Silicon Integration  

E-print Network

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

Bowers, John

4

A separable shadow Hamiltonian hybrid Monte Carlo method  

PubMed Central

Hybrid Monte Carlo (HMC) is a rigorous sampling method that uses molecular dynamics (MD) as a global Monte Carlo move. The acceptance rate of HMC decays exponentially with system size. The shadow hybrid Monte Carlo (SHMC) was previously introduced to reduce this performance degradation by sampling instead from the shadow Hamiltonian defined for MD when using a symplectic integrator. SHMC抯 performance is limited by the need to generate momenta for the MD step from a nonseparable shadow Hamiltonian. We introduce the separable shadow Hamiltonian hybrid Monte Carlo (S2HMC) method based on a formulation of the leapfrog?Verlet integrator that corresponds to a separable shadow Hamiltonian, which allows efficient generation of momenta. S2HMC gives the acceptance rate of a fourth order integrator at the cost of a second-order integrator. Through numerical experiments we show that S2HMC consistently gives a speedup greater than two over HMC for systems with more than 4000 atoms for the same variance. By comparison, SHMC gave a maximum speedup of only 1.6 over HMC. S2HMC has the additional advantage of not requiring any user parameters beyond those of HMC. S2HMC is available in the program PROTOMOL 2.1. A Python version, adequate for didactic purposes, is also in MDL (http:??mdlab.sourceforge.net?s2hmc). PMID:19894997

Sweet, Christopher R.; Hampton, Scott S.; Skeel, Robert D.; Izaguirre, Jes鷖 A.

2009-01-01

5

The Rational Hybrid Monte Carlo algorithm  

NASA Astrophysics Data System (ADS)

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.

Clark, Michael

2006-12-01

6

The Rational Hybrid Monte Carlo Algorithm  

E-print Network

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.

M. A. Clark

2006-10-06

7

Quasi-Monte Carlo Integration  

Microsoft Academic Search

The standard Monte Carlo approach to evaluating multidimensional integrals using (pseudo)-random integration nodes is frequently used when quadrature methods are too difficult or expensive to implement. As an alternative to the random methods, it has been suggested that lower error and improved convergence may be obtained by replacing the pseudo-random sequences with more uniformly distributed sequences known as quasi-random. In

William J. Morokoff; Russel E. Caflisch

1995-01-01

8

Monte Carlo Complexity of Parametric Integration  

E-print Network

Monte Carlo Complexity of Parametric Integration stefan heinrich and eug`ene sindambiwe Department The Monte Carlo complexity of computing integrals depending on a parameter is analyzed for smooth integrands that of previously developed Monte Carlo algorithms for parametric integration. 1 introduction Multivariate

Heinrich, Stefan

9

Monte Carlo One-dimension Integration Model  

NSDL National Science Digital Library

The Monte Carlo One-dimension Integration Model illustrates the Monte Carlo integration algorithm to compute the integral of a function f(x). The simulation allows you to select the number of random points, to make an automatic fit to the function graph in the Y axis (thus improving the accuracy of the estimation), and to display the points or not. The simulation computes the actual value of the integral using a Romberg algorithm to test the Monte Carlo integral approximation.

Franciscouembre

2012-02-08

10

Multiple-time-stepping generalized hybrid Monte Carlo methods  

NASA Astrophysics Data System (ADS)

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.

Escribano, Bruno; Akhmatskaya, Elena; Reich, Sebastian; Azpiroz, Jon M.

2015-01-01

11

Monte Carlo Integration Lecture 2 The Problem  

E-print Network

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

Liang, Faming

12

A Hybrid Monte Carlo Method for Accurate and Efficient  

E-print Network

A Hybrid Monte Carlo Method for Accurate and Efficient Subsurface Scattering Li, Pellacini #12;Previous work 路 Accurate for all materials, but inefficient 颅 Monte Carlo path/light tracing 路 Accurate and Efficient for all materials 颅 As accurate as Monte Carlo 颅 More efficient than Monte Carlo

Pellacini, Fabio

13

Advanced topics 5.1 Hybrid Monte Carlo  

E-print Network

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 路 Claim: The transition probability Eq. (5.3) satisfies the stationarity condition

Schofield, Jeremy

14

Physically Based Rendering Monte Carlo Integration  

E-print Network

Physically Based Rendering (600.657) Monte Carlo Integration #12;Goals In performing sampling we sampling #12;Russian Roulette Given a PDF p and a function f, the Monte- Carlo estimate of the integral is probability q(x). 2. Choose replacement value c (e.g. c=0). 3. With probability q(x) do not evaluate

Kazhdan, Michael

15

Hybrid optofluidic integration.  

PubMed

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

Parks, Joshua W; Cai, Hong; Zempoaltecatl, Lynnell; Yuzvinsky, Thomas D; Leake, Kaelyn; Hawkins, Aaron R; Schmidt, Holger

2013-10-21

16

Parallel Hybrid Monte Carlo Algorithms for Matrix Computations  

E-print Network

Parallel Hybrid Monte Carlo Algorithms for Matrix Computations V. Alexandrov1 , E. Atanassov2 , I Equations (SLAE). Monte Carlo meth- ods are used for the stochastic approximation, since it is known experimental results are presented. Keywords: Monte Carlo Method, Markov Chain, Matrix Inversion, So- lution

Dimov, Ivan

17

Hybrid Monte Carlo Simulation of Graphene on the Hexagonal Lattice  

E-print Network

We present a method for direct hybrid Monte Carlo simulation of graphene on the hexagonal lattice. We compare the results of the simulation with exact results for a unit hexagonal cell system, where the Hamiltonian can be solved analytically.

Brower, R C; Schaich, D

2011-01-01

18

Hybrid Monte Carlo Simulation of Graphene on the Hexagonal Lattice  

E-print Network

We present a method for direct hybrid Monte Carlo simulation of graphene on the hexagonal lattice. We compare the results of the simulation with exact results for a unit hexagonal cell system, where the Hamiltonian can be solved analytically.

R. C. Brower; C. Rebbi; D. Schaich

2011-01-26

19

Hybrid Monte Carlo simulation on the graphene hexagonal lattice  

E-print Network

One of the many remarkable properties of graphene is that in the low energy limit the dynamics of its electrons can be effectively described by the massless Dirac equation. This has prompted investigations of graphene based on the lattice simulation of a system of 2-dimensional fermions on a square staggered lattice. We demonstrate here how to construct the path integral for graphene working directly on the graphene hexagonal lattice. For the nearest neighbor tight binding model interacting with a long range Coulomb interaction between the electrons, this leads to the hybrid Monte Carlo algorithm with no sign problem. The only approximation is the discretization of the Euclidean time. So as we extrapolate to the time continuum limit, the exact tight binding solution maybe found numerically to arbitrary precession on a finite hexagonal lattice. The potential for this approach is tested on a single hexagonal cell.

Brower, Richard; Schaich, David

2012-01-01

20

Hybrid Monte Carlo simulation on the graphene hexagonal lattice  

E-print Network

One of the many remarkable properties of graphene is that in the low energy limit the dynamics of its electrons can be effectively described by the massless Dirac equation. This has prompted investigations of graphene based on the lattice simulation of a system of 2-dimensional fermions on a square staggered lattice. We demonstrate here how to construct the path integral for graphene working directly on the graphene hexagonal lattice. For the nearest neighbor tight binding model interacting with a long range Coulomb interaction between the electrons, this leads to the hybrid Monte Carlo algorithm with no sign problem. The only approximation is the discretization of the Euclidean time. So as we extrapolate to the time continuum limit, the exact tight binding solution maybe found numerically to arbitrary precession on a finite hexagonal lattice. The potential for this approach is tested on a single hexagonal cell.

Richard Brower; Claudio Rebbi; David Schaich

2012-04-24

21

Physically Based Rendering Monte Carlo Integration  

E-print Network

Physically Based Rendering (600.657) Monte Carlo Integration #12;Probability Definition, and f2 and constant c: ][)()()()( fcEdxxpxfcdxxpxcfcfE pp cdxxpcdxxcpcEp )()( #12;Probability Note: For functions f, f1, and f2 and constant c: 21 212121 )()()()()()()( fEfE

Kazhdan, Michael

22

Path integral Monte Carlo applied to vortices  

Microsoft Academic Search

The thermodynamic properties of the vortex lattice in a high-Tc superconductor can be understood by considering a system of bosons in two dimensions. In this picture, the imaginary time world-line of the boson corresponds to the vortex. The vortex lattice melting transition maps to melting the Bose Wigner crystal by means of increasing hbar. We use Path Integral Monte Carlo

Henrik Nordborg; Gianni Blatter

1996-01-01

23

Monte Carlo Integration This chapter gives an introduction to Monte Carlo integration. The main goals are to review  

E-print Network

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

Stanford University

24

Integrated hybrid silicon triplexer.  

PubMed

We demonstrate an integrated triplexer on silicon with a compact size of 1mm by 3.5mm by utilizing a selective area wafer bonding technique. The wavelength demultiplexer on the triplexer chip successfully separates signals at wavelengths of 1310 nm, 1490 nm and 1550 nm with more than 10 dB extinction ratio. The measured 3 dB bandwidth of the integrated laser and photodetectors are 2 GHz and 16 GHz, respectively. Open eye diagrams are also measured for the integrated photodetector up to 12.5 GHz PRBS inputs. PMID:21164734

Chang, Hsu-Hao; Kuo, Ying-hao; Jones, Richard; Barkai, Assia; Bowers, John E

2010-11-01

25

Testing a Fourier Accelerated Hybrid Monte Carlo Algorithm  

E-print Network

We describe a Fourier Accelerated Hybrid Monte Carlo algorithm suitable for dynamical fermion simulations of non-gauge models. We test the algorithm in supersymmetric quantum mechanics viewed as a one-dimensional Euclidean lattice field theory. We find dramatic reductions in the autocorrelation time of the algorithm in comparison to standard HMC.

S. Catterall; S. Karamov

2001-12-17

26

Simple Monte Carlo Integration Importance Sampling The Law of Large Numbers  

E-print Network

Simple Monte Carlo Integration Importance Sampling Topic 10 The Law of Large Numbers Monte Carlo Integration 1 / 13 #12;Simple Monte Carlo Integration Importance Sampling Outline Simple Monte Carlo Integration Importance Sampling 2 / 13 #12;Simple Monte Carlo Integration Importance Sampling Monte Carlo

Watkins, Joseph C.

27

Constant pressure hybrid Monte Carlo simulations in GROMACS.  

PubMed

Adaptation and implementation of the Generalized Shadow Hybrid Monte Carlo (GSHMC) method for molecular simulation at constant pressure in the NPT ensemble are discussed. The resulting method, termed NPT-GSHMC, combines Andersen barostat with GSHMC to enable molecular simulations in the environment natural for biological applications, namely, at constant pressure and constant temperature. Generalized Hybrid Monte Carlo methods are designed to maintain constant temperature and volume and extending their functionality to preserving pressure is not trivial. The theoretical formulation of NPT-GSHMC was previously introduced. Our main contribution is the implementation of this methodology in the GROMACS molecular simulation package and the evaluation of properties of NPT-GSHMC, such as accuracy, performance, effectiveness for real physical systems in comparison with well-established molecular simulation techniques. Benchmarking tests are presented and the obtained preliminary results are promising. For the first time, the generalized hybrid Monte Carlo simulations at constant pressure are available within the popular open source molecular dynamics software package. PMID:25408507

Fern醤dez-Pend醩, Mario; Escribano, Bruno; Radivojevi?, Tijana; Akhmatskaya, Elena

2014-12-01

28

Monte Carlo Reliability Model for Microwave Monolithic Integrated Circuits  

E-print Network

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

Rubloff, Gary W.

29

Parallel Monte Carlo Approach for Integration of the Rendering Equation  

E-print Network

Parallel Monte Carlo Approach for Integration of the Rendering Equation Ivan T. Dimov1 , Anton A are the Monte Carlo methods for solving the rendering equation in order to create photorealistic images. In this work we consider the Monte Carlo solving of the render- ing equation in the context of the parallel

Dimov, Ivan

30

A Primer in Monte Carlo Integration Using Mathcad  

ERIC Educational Resources Information Center

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

Hoyer, Chad E.; Kegerreis, Jeb S.

2013-01-01

31

Monte Carlo simulation for solving Fredholm integral equations  

Microsoft Academic Search

Purpose The purpose of this paper is to provide a Monte Carlo variance reduction method based on Control variates to solve Fredholm integral equations of the second kind. Design\\/methodology\\/approach A numerical algorithm consisted of the combined use of the successive substitution method and Monte Carlo simulation is established for the solution of Fredholm integral equations of the second

Rahman Farnoosh; Ebrahimi Morteza

2009-01-01

32

Bayesian Inference in Econometric Models Using Monte Carlo Integration  

Microsoft Academic Search

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

John Geweke

1989-01-01

33

Short-Term Load Forecasting Using Bayesian Neural Networks Learned by Hybrid Monte Carlo Algorithm  

Microsoft Academic Search

This paper develops a Bayesian technique to design an optimal neural network model for short term load forecasting. We use Hybrid Monte Carlo algorithm as a learning scheme to yield the weight vector of Bayesian neural network. In Hybrid Monte Carlo learning algorithm, the Bayesian neural network is considered as a special Hamiltonian dynamical system. The Hamilton function is precisely

Dong-xiao Niu; Hui-feng Shi; Desheng Dash Wu

34

Bayesian Training of Backpropagation Networks by the Hybrid Monte Carlo Method  

Microsoft Academic Search

. 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

Radford Neal

1993-01-01

35

A hybrid Monte Carlo and response matrix Monte Carlo method in criticality calculation  

SciTech Connect

Full core calculations are very useful and important in reactor physics analysis, especially in computing the full core power distributions, optimizing the refueling strategies and analyzing the depletion of fuels. To reduce the computing time and accelerate the convergence, a method named Response Matrix Monte Carlo (RMMC) method based on analog Monte Carlo simulation was used to calculate the fixed source neutron transport problems in repeated structures. To make more accurate calculations, we put forward the RMMC method based on non-analog Monte Carlo simulation and investigate the way to use RMMC method in criticality calculations. Then a new hybrid RMMC and MC (RMMC+MC) method is put forward to solve the criticality problems with combined repeated and flexible geometries. This new RMMC+MC method, having the advantages of both MC method and RMMC method, can not only increase the efficiency of calculations, also simulate more complex geometries rather than repeated structures. Several 1-D numerical problems are constructed to test the new RMMC and RMMC+MC method. The results show that RMMC method and RMMC+MC method can efficiently reduce the computing time and variations in the calculations. Finally, the future research directions are mentioned and discussed at the end of this paper to make RMMC method and RMMC+MC method more powerful. (authors)

Li, Z.; Wang, K. [Dept. of Engineering Physics, Tsinghua Univ., Beijing, 100084 (China)

2012-07-01

36

Hybrid S[sub N]\\/Monte Carlo research and results  

Microsoft Academic Search

The neutral particle transport equation is solved by a hybrid method that iteratively couples regions where deterministic (S[sub N]) and stochastic (Monte Carlo) methods are applied. The Monte Carlo and S[sub N] regions are fully coupled in the sense that no assumption is made about geometrical separation or decoupling. The hybrid Monte Carlo\\/S[sub N] method provides a new means of

1993-01-01

37

Hybrid S{sub N}\\/Monte Carlo research and results  

Microsoft Academic Search

The neutral particle transport equation is solved by a hybrid method that iteratively couples regions where deterministic (S{sub N}) and stochastic (Monte Carlo) methods are applied. The Monte Carlo and S{sub N} regions are fully coupled in the sense that no assumption is made about geometrical separation or decoupling. The hybrid Monte Carlo\\/S{sub N} method provides a new means of

1993-01-01

38

A Monte Carlo method for high dimensional integration  

Microsoft Academic Search

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

Yosihiko Ogata

1989-01-01

39

Markov chain Monte Carlo techniques in iterative detectors: a novel approach based on Monte Carlo integration  

Microsoft Academic Search

We present a novel soft-in soft-out (SISO) detection scheme based on Markov-chain Monte-Carlo (MCMC) simulations. The proposed detector is applicable to both synchronous multiuser and multiple-input multiple-output (MIMO) communication systems. Unlike previous publications on the subject, we use Monte Carlo integration technique to arrive at the receiver structure. The proposed multiuser\\/MIMO detector is found to follow the Rao-Blackwell formulation and

Zhenning Shi; Haidong Zhu; Behrouz Farhang-Boroujeny

2004-01-01

40

Quantum Monte Carlo calculations of the energy-level alignment at hybrid interfaces: Role of many-body effects  

E-print Network

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

Wu, Zhigang

41

Using Supervised Learning to Improve Monte Carlo Integral Estimation  

Microsoft Academic Search

Monte Carlo (MC) techniques are often used to estimate integrals of a multivariate function using randomly generated samples of the function. In light of the increasing interest in uncertainty quantification and robust design applications in aerospace engineering, the calculation of expected values of such functions (e.g. performance measures) becomes important. However, MC techniques often suffer from high variance and slow

Brendan Tracey; David Wolpert; Juan J. Alonso

2011-01-01

42

a Path Integral Monte Carlo Method for the Quasielastic Response  

Microsoft Academic Search

We formulate the quasielastic response of a non -relativistic many-body system at zero temperature in terms of ground state density matrix elements and real time path integrals that embody the final state interactions. While the former provide the weight for a conventional Monte Carlo calculation, the latter require a more sophisticated treatment. We argue that the recently developed Stationary Phase

Carlo Carraro

1990-01-01

43

Path Integral Monte-Carlo Calculations for Relativistic Oscillator  

E-print Network

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.

Alexandr Ivanov; Oleg Pavlovsky

2014-11-11

44

PLC hybrid integration technology and its application to photonic components  

Microsoft Academic Search

Silica-based planar lightwave circuit (PLC) hybrid integration is a promising way to provide highly functional photonic components. This paper is an overview of recent progress in PLC hybrid integration technology including optoelectronic semiconductor devices for the hybrid integration, various devices for wavelength-division multiplexing, and all-optical time-division multiplexing

Kuniharu Kato; Yuichi Tohmori

2000-01-01

45

Path Integral Monte Carlo Calculation of the Deuterium Hugoniot B. Militzer and D. M. Ceperley  

E-print Network

Path Integral Monte Carlo Calculation of the Deuterium Hugoniot B. Militzer and D. M. Ceperley-Champaign, Urbana, IL 61801 (January 21, 2000) Restricted path integral Monte Carlo simulations have been used path integral Monte Carlo simulations (PIMC) [6,7,5] and density functional theory molecular dynamics

Militzer, Burkhard

46

Path Integral Monte Carlo Simulation of the Low-Density Hydrogen Plasma B. Militzer y  

E-print Network

Path Integral Monte Carlo Simulation of the Low-Density Hydrogen Plasma B. Militzer y Lawrence-Champaign, Urbana, IL 61801 (Dated: January 23, 2001) Restricted path integral Monte Carlo simulations are used@uiuc.edu restricted path integral Monte Carlo simulations (PIMC) [4{6] and density functional theory molecular

Militzer, Burkhard

47

Path integral Monte Carlo on a lattice: Extended states  

NASA Astrophysics Data System (ADS)

The equilibrium properties of a single quantum particle (qp) interacting with a classical gas for a wide range of temperatures that explore the system's behavior in the classical as well as in the quantum regime is investigated. Both the qp and atoms are restricted to the sites of a one-dimensional lattice. A path integral formalism is developed within the context of the canonical ensemble in which the qp is represented by a closed, variable-step random walk on the lattice. Monte Carlo methods are employed to determine the system's properties. For the case of a free particle, analytical expressions for the energy, its fluctuations, and the qp-qp correlation function are derived and compared with the Monte Carlo simulations. To test the usefulness of the path integral formalism, the Metropolis algorithm is employed to determine the equilibrium properties of the qp for a periodic interaction potential, forcing the qp to occupy extended states. We consider a striped potential in one dimension, where every other lattice site is occupied by an atom with potential ?, and every other lattice site is empty. This potential serves as a stress test for the path integral formalism because of its rapid site-to-site variation. An analytical solution was determined in this case by utilizing Bloch's theorem due to the periodicity of the potential. Comparisons of the potential energy, the total energy, the energy fluctuations, and the correlation function are made between the results of the Monte Carlo simulations and the analytical calculations.

O'Callaghan, Mark; Miller, Bruce N.

2014-04-01

48

Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense Helium  

E-print Network

Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense integral Monte Carlo (PIMC) and density func- tional molecular dynamics (DFT-MD), are applied to study hot quantum Monte Carlo calculations7 . The dif- ference arises because standard DFT methods underesti- mate

Militzer, Burkhard

49

A path integral Monte Carlo method for R閚yi entanglement entropies  

E-print Network

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.

C. M. Herdman; Stephen Inglis; P. -N. Roy; R. G. Melko; A. Del Maestro

2014-04-28

50

Hybrid Monte Carlo algorithm for lattice QCD with two flavors of dynamical Ginsparg-Wilson quarks  

E-print Network

We study aspects concerning numerical simulations of Lattice QCD with two flavors of dynamical Ginsparg-Wilson quarks with degenerate masses. A Hybrid Monte Carlo algorithm is described and the formula for the fermionic force is derived for two specific implementations. The implementation with optimal rational approximation method is favored both in CPU time and memory consumption.

Chuan Liu

1998-11-04

51

The S/sub N//Monte Carlo response matrix hybrid method  

SciTech Connect

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.

Filippone, W.L.; Alcouffe, R.E.

1987-01-01

52

Hybrid Probabilistic RoadMap - Monte Carlo Motion Planning for Closed Chain Systems with Spherical Joints  

Microsoft Academic Search

In this paper we propose a hybrid Probabilistic RoadMap - Monte Carlo (PRM-MC) motion planner developed under the general methodology of PRM. For a given robot, PRM planners generally need to sample and connect a large number of robot congurations in order to build a roadmap that reects the properties (such as the connectivity or energy landscape) of the

Li Han

2004-01-01

53

Path integral Monte Carlo on a lattice: extended states  

E-print Network

The equilibrium properties of a single quantum particle (qp) interacting with a classical gas for a wide range of temperatures that explore the system's behavior in the classical as well as in the quantum regime is investigated. Both the quantum particle and atoms are restricted to the sites of a one-dimensional lattice. A path-integral formalism is developed within the context of the canonical ensemble in which the quantum particle is represented by a closed, variable-step random walk on the lattice. Monte Carlo methods are employed to determine the system's properties. For the case of a free particle, analytical expressions for the energy, its fluctuations, and the qp-qp correlation function are derived and compared with the Monte Carlo simulations. To test the usefulness of the path integral formalism, the Metropolis algorithm is employed to determine the equilibrium properties of the qp for a periodic interaction potential, forcing the qp to occupy extended states. We consider a striped potential in one dimension, where every other lattice site is occupied by an atom with potential $\\epsilon$, and every other lattice site is empty. This potential serves as a stress test for the path integral formalism because of its rapid site-to-site variation. An analytical solution was determined in this case by utilizing Bloch's theorem due to the periodicity of the potential. Comparisons of the potential energy, the total energy, the energy fluctuations and the correlation function are made between the results of the Monte Carlo simulations and the analytical calculations.

Mark O'Callaghan; Bruce N. Miller

2014-02-08

54

Longitudinal development of extensive air showers: Hybrid code SENECA and full Monte Carlo  

NASA Astrophysics Data System (ADS)

New experiments, exploring the ultra-high energy tail of the cosmic ray spectrum with unprecedented detail, are exerting a severe pressure on extensive air shower modelling. Detailed fast codes are in need in order to extract and understand the richness of information now available. Some hybrid simulation codes have been proposed recently to this effect (e.g., the combination of the traditional Monte Carlo scheme and system of cascade equations or pre-simulated air showers). In this context, we explore the potential of SENECA, an efficient hybrid tri-dimensional simulation code, as a valid practical alternative to full Monte Carlo simulations of extensive air showers generated by ultra-high energy cosmic rays. We extensively compare hybrid method with the traditional, but time consuming, full Monte Carlo code CORSIKA which is the de facto standard in the field. The hybrid scheme of the SENECA code is based on the simulation of each particle with the traditional Monte Carlo method at two steps of the shower development: the first step predicts the large fluctuations in the very first particle interactions at high energies while the second step provides a well detailed lateral distribution simulation of the final stages of the air shower. Both Monte Carlo simulation steps are connected by a cascade equation system which reproduces correctly the hadronic and electromagnetic longitudinal profile. We study the influence of this approach on the main longitudinal characteristics of proton, iron nucleus and gamma induced air showers and compare the predictions of the well known CORSIKA code using the QGSJET hadronic interaction model.

Ortiz, Jeferson A.; Medina-Tanco, Gustavo; de Souza, Vitor

2005-06-01

55

An Integrated Monte Carlo Methodology for the calibration of water quality models  

Microsoft Academic Search

This paper proposes an Integrated Monte Carlo Methodology (IMCM) to solve the parameter estimation problem in water quality models. The methodology is based on Bayesian approach and Markov Chain Monte Carlo techniques and it operates by means of four modules: Markov Chain Monte Carlo (MCMC), Moving Feasible Ranges (MFR), Statistical Analysis of the Joint Posterior Distribution (SAD) and Uncertainty Propagation

C. Martin; E. Ayesa

2010-01-01

56

A Quasi-Monte Carlo Method for Integration with Improved Convergence  

E-print Network

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 on the idea that ran- dom Monte Carlo techniques can often be improved by replacing the un- derlying source

Karaivanova, Aneta

57

A New Quasi-Monte Carlo Algorithm for Numerical Integration of Smooth Functions  

E-print Network

A New Quasi-Monte Carlo Algorithm for Numerical Integration of Smooth Functions Emanouil I@bas.bg, mabs@parallel.bas.bg Abstract. Bachvalov proved that the optimal order of convergence of a Monte Carlo , where s is the dimension. We con- struct a new Monte Carlo algorithm with such rate of convergence

Dimov, Ivan

58

Novel Hybrid Monte Carlo/Deterministic Technique for Shutdown Dose Rate Analyses of Fusion Energy Systems  

SciTech Connect

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.

Ibrahim, Ahmad M [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Peterson, Joshua L [ORNL] [ORNL; Grove, Robert E [ORNL] [ORNL

2013-01-01

59

When Are Quasi-Monte Carlo Algorithms Efficient for High Dimensional Integrals?  

Microsoft Academic Search

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

Ian H. Sloan; Henryk Wozniakowski

1998-01-01

60

Defects in hybrid nematic films: a Monte Carlo Simulation  

NASA Astrophysics Data System (ADS)

Monte-Carlo simulations of a nematic liquid crystal film placed between two different media that set antagonistic (planar and homeotropic) orientation of the ``molecules" at the top and the bottom surfaces are presented. This system is a model of the HAND film [1] which, as observed in experimental studies, presents the formations of topological defects induced by the different alignement at the surface. Our simulation model is based on a Lebwohl-Lasher cubic lattice [2,3] where the molecules are represented by three dimensional unit vectors and interact only with their nearest neighbors. The lateral surface of the sample are left free, i.e. no boundary conditions are specified and it is found that the ground state of the system contains stable topological defects when the lateral radius of the system is larger than its thickness. [1] O.D. Lavrentovich and V.M. Pergamnschik, Int. J. Mod. Phys. B 9, 2839 (1995). [2] P.A. Lebwohl and G. Lasher, Phys. Rev. A 6 , 426 (1972). [3] U. Fabbri and C. Zannoni, Mol. Phys., 58, 763 (1986).

Pasini, P.; Chiccoli, C.; Lavrentovich, O. D.; Zannoni, C.

1997-08-01

61

Monte Carlo Simulations of Background Spectra in Integral Imager Detectors  

NASA Technical Reports Server (NTRS)

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.

Armstrong, T. W.; Colborn, B. L.; Dietz, K. L.; Ramsey, B. D.; Weisskopf, M. C.

1998-01-01

62

Implementation of hybrid variance reduction methods in a multi group Monte Carlo code for deep shielding problems  

SciTech Connect

In this paper, the work that has been done to implement variance reduction techniques in a three dimensional, multi group Monte Carlo code - Tortilla, that works within the frame work of the commercial deterministic code - Attila, is presented. This project is aimed to develop an integrated Hybrid code that seamlessly takes advantage of the deterministic and Monte Carlo methods for deep shielding radiation detection problems. Tortilla takes advantage of Attila's features for generating the geometric mesh, cross section library and source definitions. Tortilla can also read importance functions (like adjoint scalar flux) generated from deterministic calculations performed in Attila and use them to employ variance reduction schemes in the Monte Carlo simulation. The variance reduction techniques that are implemented in Tortilla are based on the CADIS (Consistent Adjoint Driven Importance Sampling) method and the LIFT (Local Importance Function Transform) method. These methods make use of the results from an adjoint deterministic calculation to bias the particle transport using techniques like source biasing, survival biasing, transport biasing and weight windows. The results obtained so far and the challenges faced in implementing the variance reduction techniques are reported here. (authors)

Somasundaram, E.; Palmer, T. S. [Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, 116 Radiation Center, Corvallis, OR 97332-5902 (United States)

2013-07-01

63

Finite element model updating using the shadow hybrid Monte Carlo technique  

NASA Astrophysics Data System (ADS)

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.

Boulkaibet, I.; Mthembu, L.; Marwala, T.; Friswell, M. I.; Adhikari, S.

2015-02-01

64

The Brownian Bridge Does Not Offer a Consistent Advantage in Quasi-Monte Carlo Integration  

Microsoft Academic Search

The Brownian bridge has been suggested as an effective method for reducing the quasi-Monte Carlo error for problems in finance. We give an example of a digital option where the Brownian bridge performs worse than the standard discretization. Hence, the Brownian bridge does not offer a consistent advantage in quasi-Monte Carlo integration. We consider integrals of functions of d variables

Anargyros Papageorgiou

2002-01-01

65

Hybrid Monte Carlo simulation of polymer chains Department of Theoretical Physics, University of Lund, Siilvegatan 14A, S-223 62 Lund, Sweden  

E-print Network

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

Irb盲ck, Anders

66

Generalized Metropolis acceptance criterion for hybrid non-equilibrium molecular dynamicsMonte Carlo simulations  

NASA Astrophysics Data System (ADS)

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, Beno顃

2015-01-01

67

Generalized Metropolis acceptance criterion for hybrid non-equilibrium molecular dynamics-Monte Carlo simulations.  

PubMed

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

Chen, Yunjie; Roux, Beno顃

2015-01-14

68

CAD-based Monte Carlo Program for Integrated Simulation of Nuclear System SuperMC  

NASA Astrophysics Data System (ADS)

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.

Wu, Yican; Song, Jing; Zheng, Huaqing; Sun, Guangyao; Hao, Lijuan; Long, Pengcheng; Hu, Liqin

2014-06-01

69

Design of integrated hybrid silicon waveguide optical gyroscope  

E-print Network

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. 漏2014 Optical Society of America OCIS codes: (060.2800) Gyroscopes

Bowers, John

70

MODEL DEVELOPMENT FOR INTEGRATED HYBRID ELECTRIC VEHICLE DYNAMIC STABILITY SYSTEMS  

Microsoft Academic Search

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

Joel R. Anstrom

2003-01-01

71

Hybrid Silicon Evanescent Photonic Integrated Circuit John E. Bowersa  

E-print Network

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

Bowers, John

72

Hybrid Monte Carlo Simulation of Stress-Induced Texture Evolution with Inelastic Effects  

NASA Astrophysics Data System (ADS)

A hybrid Monte Carlo (HMC) approach is employed to quantify the influence of inelastic deformation on the microstructural evolution of polycrystalline materials. This approach couples a time explicit material point method (MPM) for deformation with a calibrated Monte Carlo model for grain boundary motion. A rate-independent crystal plasticity model is implemented to account for localized plastic deformations in polycrystals. The dislocation energy difference between grains provides an additional driving force for texture evolution. This plastic driving force is then brought into a MC paradigm via parametric links between MC and sharp-interface (SI) kinetic models. The MC algorithm is implemented in a parallelized setting using a checkerboard updating scheme. As expected, plastic loading favors texture evolution for grains that have a bigger Schmid factor with respect to the loading direction, and these are the grains most easily removed by grain boundary motion. A macroscopic equation is developed to predict such texture evolution.

Zhang, Liangzhe; Dingreville, R閙i; Bartel, Timothy; Lusk, Mark T.

2011-03-01

73

A hybrid (Monte Carlo/deterministic) approach for multi-dimensional radiation transport  

SciTech Connect

Highlights: {yields} We introduce a variance reduction scheme for Monte Carlo (MC) transport. {yields} The primary application is atmospheric remote sensing. {yields} The technique first solves the adjoint problem using a deterministic solver. {yields} Next, the adjoint solution is used as an importance function for the MC solver. {yields} The adjoint problem is solved quickly since it ignores the volume. - Abstract: A novel hybrid Monte Carlo transport scheme is demonstrated in a scene with solar illumination, scattering and absorbing 2D atmosphere, a textured reflecting mountain, and a small detector located in the sky (mounted on a satellite or a airplane). It uses a deterministic approximation of an adjoint transport solution to reduce variance, computed quickly by ignoring atmospheric interactions. This allows significant variance and computational cost reductions when the atmospheric scattering and absorption coefficient are small. When combined with an atmospheric photon-redirection scheme, significant variance reduction (equivalently acceleration) is achieved in the presence of atmospheric interactions.

Bal, Guillaume, E-mail: gb2030@columbia.edu [Department of Applied Physics and Applied Mathematics, Columbia University, 200 S.W. Mudd Building, 500 W. 120th Street, New York, NY 10027 (United States); Davis, Anthony B., E-mail: Anthony.B.Davis@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-237, Pasadena, CA 91109 (United States); Kavli Institute for Theoretical Physics, Kohn Hall, University of California, Santa Barbara, CA 93106-4030 (United States); Langmore, Ian, E-mail: ianlangmore@gmail.com [Department of Applied Physics and Applied Mathematics, Columbia University, 200 S.W. Mudd Building, 500 W. 120th Street, New York, NY 10027 (United States)

2011-08-20

74

Hybrid Parallel Programming Models for AMR Neutron Monte-Carlo Transport  

NASA Astrophysics Data System (ADS)

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.

Dureau, David; Po雝te, Ga雔

2014-06-01

75

Hybrid imaging: integration of nuclear imaging and cardiac CT.  

PubMed

The integration of nuclear medicine cameras with multidetector CT scanners provides a unique opportunity to delineate cardiac and vascular anatomic abnormalities and their physiologic consequences in a single setting. By revealing the burden of anatomic coronary artery disease and its physiologic significance, hybrid imaging can provide unique information that may improve noninvasive diagnosis, risk assessment, and management of coronary artery disease. By integrating the detailed anatomic information from CT with the high sensitivity of radionuclide imaging to evaluate targeted molecular and cellular abnormalities, hybrid imaging may play a key role in shaping the future of molecular diagnostics and therapeutics. This article reviews potential clinical applications of hybrid imaging in cardiovascular disease. PMID:19306768

Di Carli, Marcelo F

2009-05-01

76

Plug-in integrated/hybrid circuit  

NASA Technical Reports Server (NTRS)

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.

Stringer, E. J.

1974-01-01

77

A Frequency Analysis of Monte-Carlo and other Numerical Integration Schemes  

E-print Network

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 ...

Durand, Fr閐o

2011-12-14

78

Iterative Monte Carlo path integral with optimal grids from whole-necklace Vikram Jadhao1  

E-print Network

the path integral rep- resentation of the real-time propagator has formally the same form, the quantum func- tions, are unable to deal with such dramatic phase cancellation,6,7 and thus the path integralIterative Monte Carlo path integral with optimal grids from whole-necklace sampling Vikram Jadhao1

Makri, Nancy

79

Complexity of Monte Carlo Algorithms for a Class of Integral Equations  

Microsoft Academic Search

In this work we study the computational complexity of a class of grid Monte Carlo algorithms for integral equations. The idea of the algorithms consists in an approximation of the integral equation\\u000a by a system of algebraic equations. Then the Markov chain iterative Monte Carlo is used to solve the system. The assumption\\u000a here is that the corresponding Neumann series

Ivan Dimov; Rayna Georgieva

2007-01-01

80

Hybrid Online Education: Identifying Integration Models Using Adventure Learning  

ERIC Educational Resources Information Center

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

Doering, Aaron; Veletsianos, George

2008-01-01

81

Improved methods for path integral Monte Carlo integration in fermionic systems  

NASA Astrophysics Data System (ADS)

We generalize the discretized Feynman path integral expansion by replacing the path through pure states with a path through idempotent density matrices. The transformed expression converges to the ordinary path integral, but is computationally more flexible than the ordinary form. By introducing a particular choice of these idempotent density matrices, based on rotational averaging around the two-particle center of mass, we greatly reduce the sign problem for systems of two fermions in three dimensions. In the ordinary path integral Monte Carlo approach, low temperature simulation of fermions is inefficient as the integral decays exponentially faster than the integrand (and its variance) as the temperature decreases. The new rotationally averaged algorithm dramatically retards this relative decay. Fermionic simulations of the model system of Kestner and Sinanoglu, and of the harmonic oscillator, demonstrate this improvement, as integrals calculated at temperatures much lower than the singlet-triplet splitting display negligible decay of the desired averages relative to the partition function of the modified path ensemble.

Newman, William H.; Kuki, Atsuo

1992-01-01

82

Hybrid Monte Carlo/Deterministic Methods for Accelerating Active Interrogation Modeling  

SciTech Connect

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.

Peplow, Douglas E. [ORNL; Miller, Thomas Martin [ORNL; Patton, Bruce W [ORNL; Wagner, John C [ORNL

2013-01-01

83

Efficient hybrid non-equilibrium molecular dynamics--Monte Carlo simulations with symmetric momentum reversal.  

PubMed

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

Chen, Yunjie; Roux, Beno顃

2014-09-21

84

Hybrid Monte-Carlo simulation of interacting tight-binding model of graphene  

E-print Network

In this work, results are presented of Hybrid-Monte-Carlo simulations of the tight-binding Hamiltonian of graphene, coupled to an instantaneous long-range two-body potential which is modeled by a Hubbard-Stratonovich auxiliary field. We present an investigation of the spontaneous breaking of the sublattice symmetry, which corresponds to a phase transition from a conducting to an insulating phase and which occurs when the effective fine-structure constant $\\alpha$ of the system crosses above a certain threshold $\\alpha_C$. Qualitative comparisons to earlier works on the subject (which used larger system sizes and higher statistics) are made and it is established that $\\alpha_C$ is of a plausible magnitude in our simulations. Also, we discuss differences between simulations using compact and non-compact variants of the Hubbard field and present a quantitative comparison of distinct discretization schemes of the Euclidean time-like dimension in the Fermion operator.

Dominik Smith; Lorenz von Smekal

2013-11-05

85

Hybrid Monte-Carlo simulation of interacting tight-binding model of graphene  

E-print Network

In this work, results are presented of Hybrid-Monte-Carlo simulations of the tight-binding Hamiltonian of graphene, coupled to an instantaneous long-range two-body potential which is modeled by a Hubbard-Stratonovich auxiliary field. We present an investigation of the spontaneous breaking of the sublattice symmetry, which corresponds to a phase transition from a conducting to an insulating phase and which occurs when the effective fine-structure constant $\\alpha$ of the system crosses above a certain threshold $\\alpha_C$. Qualitative comparisons to earlier works on the subject (which used larger system sizes and higher statistics) are made and it is established that $\\alpha_C$ is of a plausible magnitude in our simulations. Also, we discuss differences between simulations using compact and non-compact variants of the Hubbard field and present a quantitative comparison of distinct discretization schemes of the Euclidean time-like dimension in the Fermion operator.

Smith, Dominik

2013-01-01

86

Automatic Mesh Adaptivity for Hybrid Monte Carlo/Deterministic Neutronics Modeling of Fusion Energy Systems  

SciTech Connect

Three mesh adaptivity algorithms were developed to facilitate and expedite the use of the CADIS and FW-CADIS hybrid Monte Carlo/deterministic techniques in accurate full-scale neutronics simulations of fusion energy systems with immense sizes and complicated geometries. First, a macromaterial approach enhances the fidelity of the deterministic models without changing the mesh. Second, a deterministic mesh refinement algorithm generates meshes that capture as much geometric detail as possible without exceeding a specified maximum number of mesh elements. Finally, a weight window coarsening algorithm decouples the weight window mesh and energy bins from the mesh and energy group structure of the deterministic calculations in order to remove the memory constraint of the weight window map from the deterministic mesh resolution. The three algorithms were used to enhance an FW-CADIS calculation of the prompt dose rate throughout the ITER experimental facility and resulted in a 23.3% increase in the number of mesh tally elements in which the dose rates were calculated in a 10-day Monte Carlo calculation. Additionally, because of the significant increase in the efficiency of FW-CADIS simulations, the three algorithms enabled this difficult calculation to be accurately solved on a regular computer cluster, eliminating the need for a world-class super computer.

Ibrahim, Ahmad M [ORNL] [ORNL; Wilson, P. [University of Wisconsin] [University of Wisconsin; Sawan, M. [University of Wisconsin] [University of Wisconsin; Mosher, Scott W [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Grove, Robert E [ORNL] [ORNL

2013-01-01

87

Quasielastic response with a real-time path-integral Monte Carlo method  

Microsoft Academic Search

We formulate the quasielastic response of a nonrelativistic many-body system at zero temperature in terms of ground-state density-matrix elements and real-time path integrals that embody the final-state interactions. While the former provide the weight for a conventional Monte Carlo calculation, the latter require a more sophisticated treatment. We argue that the stationary-phase Monte Carlo technique recently developed by Doll et

C. Carraro; S. E. Koonin

1990-01-01

88

Monte Carlo Variance of Scrambled Net Quadrature  

Microsoft Academic Search

Hybrids of equidistribution and Monte Carlo methods of integration can achieve the superior accuracy of the former while allowing the simple error estimation methods of the latter. This paper studies the variance of one such hybrid, scrambled nets, by applying a multidimensional multiresolution (wavelet) analysis to the integrand. The integrand is assumed to be measurable and square integrable but not

Art B. Owen

1997-01-01

89

Hybrid III-V/silicon SOA for photonic integrated circuits  

NASA Astrophysics Data System (ADS)

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.

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

90

Hybrid integration of fiber optic gyroscopes operating in harsh environments  

NASA Astrophysics Data System (ADS)

The development of the first fully integrated 4-channel fiber optic gyroscope "optical engine" is presented. The optical engine integrates the equivalent of more than 24 discrete optical components into a hybrid chip with a size of 67x11x3 mm. After the optical engine is spliced to fiber sensor coils, the performance of the gyroscope has been benchmarked to be equivalent to the performance of a navigation grade gyroscope fabricated with discrete components.

Bischel, William K.; Kouchnir, Mikhail A.; Bitter, Martin; Yahalom, Ram; Taylor, Edward W.

2011-09-01

91

Feasibility of a Monte Carlo-deterministic hybrid method for fast reactor analysis  

SciTech Connect

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)

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

92

Quantum Monte Carlo dynamics: The stationary phase Monte Carlo path integral calculation of finite temperature time correlation functions  

NASA Astrophysics Data System (ADS)

We present a numerically exact procedure for the calculation of an important class of finite temperature quantum mechanical time correlation functions. The present approach is based around the stationary phase Monte Carlo (SPMC) method, a general mathematical tool for the calculation of high dimensional averages of oscillatory integrands. In the present context the method makes possible the direct numerical path integral calculation of real-time quantum dynamical quantities for times appreciably greater than the thermal time (??). Illustrative applications involving finite temperature anharmonic motion are presented. Issues of importance with respect to future applications are identified and discussed.

Doll, J. D.; Beck, Thomas L.; Freeman, David L.

1988-11-01

93

A hybrid phase-space and histogram source model for GPU-based Monte Carlo radiotherapy dose calculation.  

PubMed

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

Townson, Reid W; Zavgorodni, Sergei

2014-11-26

94

Monte Carlo Integration for Quasi杔inear Models  

Microsoft Academic Search

In this contribution we consider the inversion of quasi-linear models by means of Monte-Carlo methods. Quasi-linear models\\u000a are a special class of non-linear models, which can be formally written in matrix-vector formulation but whose design matrix\\u000a depends on a subset of the unknown parameters. A large class of geodetic problems can be recast as quasi-linear models. As\\u000a there exist no

B. Gundlich; J. Kusche

95

The integration of improved Monte Carlo compton scattering algorithms into the Integrated TIGER Series.  

SciTech Connect

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.

Quirk, Thomas, J., IV (University of New Mexico)

2004-08-01

96

Polymer waveguide based hybrid opto-electric integration technology  

NASA Astrophysics Data System (ADS)

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 24 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.

Mao, Jinbin; Deng, Lingling; Jiang, Xiyan; Ren, Rong; Zhai, Yumeng; Wang, Jin

2014-10-01

97

Mixed oxidizer hybrid propulsion system optimization under uncertainty using applied response surface methodology and Monte Carlo simulation  

NASA Astrophysics Data System (ADS)

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.

Whitehead, James Joshua

98

A quasi-Monte Carlo method for computing double and other multiple integrals  

Microsoft Academic Search

The heuristic importance of the Monte Carlo method lies in the fact that it shows the possibility of computing numerically integrals in many dimensions by taking averages of integrand values at a number of points in such a way that, for a given degree of accuracy, this number does not depend substantially on the number of dimensions of the domain

S. K. Zaremba

1970-01-01

99

Comparison of hybrid and pure Monte Carlo shower generators on an event by event basis  

NASA Astrophysics Data System (ADS)

SENECA is a hybrid air shower simulation written by H. Drescher that utilizes both Monte Carlo simulation and cascade equations. By using the cascade equations only in the high energy portion of the shower, where they are extremely accurate, SENECA is able to utilize the advantages in speed from the cascade equations yet still produce complete, three dimensional particle distributions at ground level. We present a comparison, on an event by event basis, of SENECA and CORSIKA, a well trusted MC simulation. By using the same first interaction in both SENECA and CORSIKA, the effect of the cascade equations can be studied within a single shower, rather than averages over many showers. Our study shows that for showers produced in this manner, SENECA agrees with CORSIKA to a very high accuracy as to densities, energies, and timing information for individual species of ground-level particles from both iron and proton primaries with energies between 1EeV and 100EeV. Used properly, SENECA produces ground particle distributions virtually indistinguishable from those of CORSIKA in a fraction of the time. For example, for a shower induced by a 40 EeV proton simulated with 10-6 thinning, SENECA is 10 times faster than CORSIKA.

Allen, J.; Drescher, H.-J.; Farrar, G.

100

Development of Subspace-based Hybrid Monte Carlo-Deterministric Algorithms for Reactor Physics Calculations  

SciTech Connect

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.

Abdel-Khalik, Hany S.; Gardner, Robin; Mattingly, John; Sood, Avneet

2014-05-20

101

Neutral depletion in inductively coupled plasmas using hybrid-type direct simulation Monte Carlo  

SciTech Connect

Neutral and ion transport phenomena were simulated by a hybrid-type direct simulation Monte Carlo (DSMC) method for a one-dimensional (1D) electrostatic plasma in Ar/N{sub 2} mixtures to identify the mechanism of neutral depletion. The results show that gas heating and pressure balance are the main mechanisms of neutral depletion in an inductively coupled plasma. When plasma pressure becomes comparable to neutral pressure in high density plasma sources (T{sub e}{approx}2-5 eV, n{sub e}{approx}10{sup 11}-10{sup 12} cm{sup -3}), the total pressure (neutral pressure and plasma pressure) is conserved. Therefore, the finite plasma pressure (mainly electron pressure) reduces the neutral pressure. Neutrals collide with ions that have been accelerated by the ambipolar electric field and with Franck-Condon dissociated atoms, resulting in gas heating. Significant neutral depletion (up to 90%) is found at the typical condition of inductively coupled plasma process reactors. The resulting neutral depletion enhances the plasma transport to the surrounding wall, increases the particle loss, and decreases the plasma density.

Shimada, Masashi; Tynan, George R.; Cattolica, Robert [Department of Mechanical and Aerospace Engineering, and Center for Energy Research, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States)

2008-02-01

102

Nucleation free-energy barriers with Hybrid Monte-Carlo/Umbrella Sampling.  

PubMed

The aim of this work is to evaluate nucleation free-energy barriers using molecular dynamics (MD). More specifically, we use a combination of Hybrid Monte Carlo (HMC) and an Umbrella Sampling scheme, and compute the crystallisation barrier of NaCl from its melt. Firstly the convergence and performance of HMC for different time-steps and the number of MD steps within a HMC cycle are assessed. The calculated potential energies and densities converge regardless of the chosen time-step. However the acceptance ratio of the Metropolis step within the HMC scheme strongly depends on the time-step and affects the performance. It is shown that the acceptance ratio is close to 100% for time-steps of the order of those commonly used in molecular dynamics runs. We then explore the results obtained with a "non-Metropolised" version of HMC where the MD trajectories are always accepted (omitting the Metropolis criteria) and conclude that they are satisfactory for time-steps below 5 fs. Next, HMC is combined with Umbrella Sampling (HMC/US) to compute the nucleation free-energy for both the standard and the "non-Metropolised" HMC (using a small time-step) and in both cases find excellent agreement with the reported values. To conclude, we explore approximations to the HMC/US technique implementing HMC with isothermal-isobaric MD trajectories. The computed nucleation free-energy curve is coincident, within the statistical error, with previous calculations. PMID:25323418

Gonzalez, M A; Sanz, E; McBride, C; Abascal, J L F; Vega, C; Valeriani, C

2014-12-01

103

Numerical methods for the QCD overlap operator IV: Hybrid Monte Carlo  

NASA Astrophysics Data System (ADS)

The computational costs of calculating the matrix sign function of the overlap operator together with fundamental numerical problems related to the discontinuity of the sign function in the kernel eigenvalues are the major obstacle towards simulations with dynamical overlap fermions using the Hybrid Monte Carlo algorithm. In a previous paper of the present series we introduced optimal numerical approximation of the sign function and have developed highly advanced preconditioning and relaxation techniques which speed up the inversion of the overlap operator by nearly an order of magnitude. In this fourth paper of the series we construct an HMC algorithm for overlap fermions. We approximate the matrix sign function using the Zolotarev rational approximation, treating the smallest eigenvalues of the Wilson operator exactly within the fermionic force. Based on this we derive the fermionic force for the overlap operator. We explicitly solve the problem of the Dirac delta-function terms arising through zero crossings of eigenvalues of the Wilson operator. The main advantage of scheme is that its energy violations scale better than O(??) and thus are comparable with the violations of the standard leapfrog algorithm over the course of a trajectory. We explicitly prove that our algorithm satisfies reversibility and area conservation. We present test results from our algorithm on 4 4, 6 4, and 8 4 lattices.

Cundy, N.; Krieg, S.; Arnold, G.; Frommer, A.; Lippert, Th.; Schilling, K.

2009-01-01

104

Graphene/Si CMOS Hybrid Hall Integrated Circuits  

PubMed Central

Graphene/silicon CMOS hybrid integrated circuits (ICs) should provide powerful functions which combines the ultra-high carrier mobility of graphene and the sophisticated functions of silicon CMOS ICs. But it is difficult to integrate these two kinds of heterogeneous devices on a single chip. In this work a low temperature process is developed for integrating graphene devices onto silicon CMOS ICs for the first time, and a high performance graphene/CMOS hybrid Hall IC is demonstrated. Signal amplifying/process ICs are manufactured via commercial 0.18?um silicon CMOS technology, and graphene Hall elements (GHEs) are fabricated on top of the passivation layer of the CMOS chip via a low-temperature micro-fabrication process. The sensitivity of the GHE on CMOS chip is further improved by integrating the GHE with the CMOS amplifier on the Si chip. This work not only paves the way to fabricate graphene/Si CMOS Hall ICs with much higher performance than that of conventional Hall ICs, but also provides a general method for scalable integration of graphene devices with silicon CMOS ICs via a low-temperature process. PMID:24998222

Huang, Le; Xu, Huilong; Zhang, Zhiyong; Chen, Chengying; Jiang, Jianhua; Ma, Xiaomeng; Chen, Bingyan; Li, Zishen; Zhong, Hua; Peng, Lian-Mao

2014-01-01

105

Novel integration technique for silicon/III-V hybrid laser.  

PubMed

Integrated semiconductor lasers on silicon are one of the most crucial devices to enable low-cost silicon photonic integrated circuits for high-bandwidth optic communications and interconnects. While optical amplifiers and lasers are typically realized in III-V waveguide structures, it is beneficial to have an integration approach which allows flexible and efficient coupling of light between III-V gain media and silicon waveguides. In this paper, we propose and demonstrate a novel fabrication technique and associated transition structure to realize integrated lasers without the constraints of other critical processing parameters such as the starting silicon layer thicknesses. This technique employs epitaxial growth of silicon in a pre-defined trench with taper structures. We fabricate and demonstrate a long-cavity hybrid laser with a narrow linewidth of 130 kHz and an output power of 1.5 mW using the proposed technique. PMID:25401832

Dong, Po; Hu, Ting-Chen; Liow, Tsung-Yang; Chen, Young-Kai; Xie, Chongjin; Luo, Xianshu; Lo, Guo-Qiang; Kopf, Rose; Tate, Alaric

2014-11-01

106

HRMC_2.1: Hybrid Reverse Monte Carlo method with silicon, carbon, germanium and silicon carbide potentials  

NASA Astrophysics Data System (ADS)

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. In this version 2.1 update, an empirical potential for silicon-carbide has been added to the code along with an experimentally motivated constraint on the bond type fraction applicable to systems containing multiple elements.

Opletal, G.; Petersen, T. C.; Russo, S. P.

2014-06-01

107

Catalyzed growth of carbon nanotube with definable chirality by hybrid molecular dynamics-force biased Monte Carlo simulations.  

PubMed

Metal-catalyzed growth mechanisms of carbon nanotubes (CNTs) were studied by hybrid molecular dynamics-Monte Carlo simulations using a recently developed ReaxFF reactive force field. Using this novel approach, including relaxation effects, a CNT with definable chirality is obtained, and a step-by-step atomistic description of the nucleation process is presented. Both root and tip growth mechanisms are observed. The importance of the relaxation of the network is highlighted by the observed healing of defects. PMID:20939511

Neyts, Erik C; Shibuta, Yasushi; van Duin, Adri C T; Bogaerts, Annemie

2010-11-23

108

Quasielastic response with a real-time path-integral Monte Carlo method  

NASA Astrophysics Data System (ADS)

We formulate the quasielastic response of a nonrelativistic many-body system at zero temperature in terms of ground-state density-matrix elements and real-time path integrals that embody the final-state interactions. While the former provide the weight for a conventional Monte Carlo calculation, the latter require a more sophisticated treatment. We argue that the stationary-phase Monte Carlo technique recently developed by Doll et al. can be used to study the approach to ``Y scaling.'' We perform calculations for a particle in a potential well in one and three dimensions and compare them with the exact results available for these models.

Carraro, C.; Koonin, S. E.

1990-04-01

109

HRMC_1.1: Hybrid Reverse Monte Carlo method with silicon and carbon potentials  

NASA Astrophysics Data System (ADS)

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.

Opletal, G.; Petersen, T. C.; O'Malley, B.; Snook, I. K.; McCulloch, D. G.; Yarovsky, I.

2011-02-01

110

Path integrals and large deviations in stochastic hybrid systems.  

PubMed

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. PMID:24827272

Bressloff, Paul C; Newby, Jay M

2014-04-01

111

Enhanced optical forces in integrated hybrid plasmonic waveguides.  

PubMed

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

Li, Huan; Noh, Jong W; Chen, Yu; Li, Mo

2013-05-20

112

Optical interconnection module integrated on a flexible optical\\/electrical hybrid printed circuit board  

Microsoft Academic Search

An optical interconnection module directly integrated on a flexible optical\\/electrical hybrid printed circuit board (O\\/E hybrid PCB) is presented. A newly proposed polymeric optical waveguide plays roles in the optical path and in a platform as an O\\/E hybrid PCB integrated with various optical\\/electrical components. The fabricated flexible O\\/E hybrid PCB had sufficient optical characteristics such as a low bending

Woo-Jin Lee; Sung Hwan Hwang; Jung Woon Lim; Che Hyun Cho; Gye Won Kim; Byung Sup Rho

2009-01-01

113

Monte Carlo thermal model of an integrating light pipe for rapid thermal processing  

SciTech Connect

A Monte Carlo model is developed to simulate transient wafer heating as a function of system parameters in a kaleidoscope- or integrating light-pipe type cavity with square cross-section. Trends in wafer temperature uniformity are examined as a function of length-to-width ratio, cavity width, and the number of heating lamps. The effect on temperature determination by a radiometer placed in the bottom end wall of the cavity is simulated.

Thomas, J.C. [Ball Aerospace and Technologies Corp., Broomfield, CO (United States); DeWitt, D.P. [Purdue Univ., West Lafayette, IN (United States). School of Mechanical Engineering

1996-12-01

114

High Voltage Dielectrophoretic and Magnetophoretic Hybrid Integrated Circuit / Microfluidic Chip  

PubMed Central

A hybrid integrated circuit (IC) / microfluidic chip is presented that independently and simultaneously traps and moves microscopic objects suspended in fluid using both electric and magnetic fields. This hybrid chip controls the location of dielectric objects, such as living cells and drops of fluid, on a 60 61 array of pixels that are 30 38 ?m2 in size, each of which can be individually addressed with a 50 V peak-to-peak, DC to 10 MHz radio frequency voltage. These high voltage pixels produce electric fields above the chip抯 surface with a magnitude , resulting in strong dielectrophoresis (DEP) forces . Underneath the array of DEP pixels there is a magnetic matrix that consists of two perpendicular sets of 60 metal wires running across the chip. Each wire can be sourced with 120 mA to trap and move magnetically susceptible objects using magnetophoresis (MP). The DEP pixel array and magnetic matrix can be used simultaneously to apply forces to microscopic objects, such as living cells or lipid vesicles, that are tagged with magnetic nanoparticles. The capabilities of the hybrid IC / microfluidic chip demonstrated in this paper provide important building blocks for a platform for biological and chemical applications. PMID:20625468

Issadore, David; Franke, Thomas; Brown, Keith A.; Hunt, Thomas P.; Westervelt, Robert M.

2010-01-01

115

Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms  

NASA Astrophysics Data System (ADS)

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.

Markos, Christos; Kubat, Irnis; Bang, Ole

2014-08-01

116

Hybrid integrated optic modules for real-time signal processing  

NASA Technical Reports Server (NTRS)

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.

Tsai, C. S.

1984-01-01

117

Hybrid two-dimensional Monte-Carlo electron transport in self-consistent electromagnetic fields  

Microsoft Academic Search

The physics and numerics of the hybrid electron transport code ANTHEM are described. The need for the hybrid modeling of laser generated electron transport is outlined, and a general overview of the hybrid implementation in ANTHEM is provided. ANTHEM treats the background ions and electrons in a laser target as coupled fluid components moving relative to a fixed Eulerian mesh.

R. J. Mason; C. W. Cranfill

1985-01-01

118

1.31-1.55-祄 Hybrid integrated optoelectronic receiver using low-loss quasi-monolithic integration technology  

NASA Astrophysics Data System (ADS)

In order to integrate photonic devices with electronic devices to realize the low-loss hybrid integrated devices. A wide spectral hybrid integrated optoelectronic receiver was fabricated by using quasi-monolithic integration technology (QMIT) in this paper. It consisted of a 8.5 GHz InGaAs photodetector and a 1.25 Gbps mature transimpedance pre-amplifier (TIA) complementrary metal oxide semiconductor (CMOS) chip. The Au layer was deposited on a designed Si platform to form planar waveguide electrode which replaced a part of bonding wire, so it reduced the parasitic parameters of the optoelectronic receiver, and then enhanced high-speed response characteristics and the stability of the hybrid integrated receiver. Finally, a 3 Gbps clear open eye diagram of the hybrid integrated optoelectronic receiver was obtained.

Luo, Yang; Huang, Yongqing; Ren, Xiaomin; Duan, Xiaofeng; Wang, Qi

2014-01-01

119

Hybrid automata of an integrated motor-transmission powertrain for automatic gear shift  

Microsoft Academic Search

This paper presents a scheme of hybrid modeling of an integrated motor-transmission powertrain, which is increasingly applied to electric vehicles. The shift process of this system is special due to the absence of clutch, and the mode switch of the propulsion motor increases hybrid characteristics. After the introduction of a definition of hybrid automaton and the analysis of shift process,

Hong Fu; Guangyu Tian; Quanshi Chen; Yiding Jin

2011-01-01

120

2001-01-1334 Integrated, Feed-Forward Hybrid Electric Vehicle  

E-print Network

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

Peng, Huei

121

An approach to hybrid power systems integration considering different renewable energy technologies  

Microsoft Academic Search

Hybrid power systems need to be evaluated based on the requirements of high penetration renewable energy technology applications. Additionally, modeling and analysis storage systems integration are also necessary to increase the effectiveness of hybrid power configurations. In the present talk, a software based simulation to understand the hybrid power systems response considering various renewable energy technologies and energy storage options

Nicolas Lopez; Jose F. Espiritu

2011-01-01

122

Two-dimensional hybrid Monte Carlo-fluid modelling of dc glow discharges: Comparison with fluid models, reliability, and accuracy  

NASA Astrophysics Data System (ADS)

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.

Eylenceo?lu, E.; Rafatov, I.; Kudryavtsev, A. A.

2015-01-01

123

Better HMC integrators for dynamical simulations  

SciTech Connect

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.

M.A. Clark, Balint Joo, A.D. Kennedy, P.J. Silva

2010-06-01

124

Study of the validity of a combined potential model using the hybrid reverse Monte Carlo method in fluoride glass system  

E-print Network

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.

S. M. Mesli; M. Habchi; M. Kotbi; H. Xu

2013-03-25

125

Golden Ratio Versus Pi as Random Sequence Sources for Monte Carlo Integration  

NASA Technical Reports Server (NTRS)

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.

Sen, S. K.; Agarwal, Ravi P.; Shaykhian, Gholam Ali

2007-01-01

126

Hybrid silicon integration R. Jones H. D. Park A. W. Fang J. E. Bowers O. Cohen  

E-print Network

Hybrid silicon integration R. Jones ? H. D. Park ? A. W. Fang ? J. E. Bowers ? O. Cohen ? 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

Bowers, John

127

Introduction to integration of renewable energy in demand controlled hybrid ventilation systems for residential buildings  

Microsoft Academic Search

In the scope of the EU supported project RESidential buildings HYbrid VENTilation (RESHYVENT), the possible integration of renewable energy solutions (RES) into hybrid ventilation systems has been analysed. The focus has been on solar and wind applications to substitute the use of fossil fuel. The feasibility of the investigated options depends on the ventilation concept the RES is integrated into,

S. Antvorskov

2008-01-01

128

Integration of conflict into integrative taxonomy: fitting hybridization in species delimitation of Mesocarabus (Coleoptera: Carabidae).  

PubMed

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

And鷍ar, C; Arribas, P; Ruiz, C; Serrano, J; G髆ez-Zurita, J

2014-09-01

129

hybridMANTIS: a CPU-GPU Monte Carlo method for modeling indirect x-ray detectors with columnar scintillators.  

PubMed

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

Sharma, Diksha; Badal, Andreu; Badano, Aldo

2012-04-21

130

Five-port hybrid-integrated MMW monopulse tracking sensor  

NASA Astrophysics Data System (ADS)

A miniature millimeter-wave tracking sensor has been developed that can provide small- diameter hypervelocity missiles with the ability to acquire and track ground mobile and airborne military threats. It has adequate power to acquire small targets at beyond one kilometer range, sufficiently low sidelobes to suppress clutter and countermeasures, and a sufficiently deep tracking null for high angular accuracy. A five-port monopulse unit, the sensor is 1.7 inches (43 mm) in diameter and weighs only 120 grams. It consists of a 94 GHz hybrid-integrated frequency-modulated continuous wave (FMCW) transceiver and a dielectric lens antenna. The transceiver, which consists of Gunn Transmitter, circulator, three mixers, three couplers, and two comparators (azimuth and elevation), is built on three thin quartz substrates. Integral with it is a cluster of five dielectric monopulse feeds. The transmitter generates more than 60 milliwatts of average power which is linearly modulated over a period of one millisecond. The modulation is sufficiently linear to permit range resolutions as high as 30 centimeters. When the sensor was tested, its beamwidth was measured at 4 degrees. Also, its sum channel sidelobes are 39 dB below the level of the main beam, and its difference null depth is 44 dB.

Hulderman, Garry N.

1993-07-01

131

Effect of electron Monte Carlo collisions on a hybrid simulation of a low-pressure capacitively coupled plasma  

NASA Astrophysics Data System (ADS)

Fluid models have been widely used and conducted successfully in high pressure plasma simulations where the drift杁iffusion and the local-field approximation are valid. However, fluid models are not able to demonstrate non-local effects related to large electron energy relaxation mean free path in low pressure plasmas. To overcome this weakness, a hybrid model coupling electron Monte Carlo collision (EMCC) method with the fluid model is introduced to obtain precise electron energy distribution functions using pseudo-particles. Steady state simulation results by a one-dimensional hybrid model which includes EMCC method for the collisional reactions but uses drift杁iffusion approximation for electron transport in a fluid model are compared with those of a conventional particle-in-cell (PIC) and a fluid model for low pressure capacitively coupled plasmas. At a wide range of pressure, the hybrid model agrees well with the PIC simulation with a reduced calculation time while the fluid model shows discrepancy in the results of the plasma density and the electron temperature.

Hwang, Seok Won; Lee, Ho-Jun; Lee, Hae June

2014-12-01

132

The performance of a hybrid analytical-Monte Carlo system response matrix in pinhole SPECT reconstruction.  

PubMed

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

El Bitar, Z; Pino, F; Candela, C; Ros, D; Pav韆, J; Rannou, F R; Ruibal, A; Aguiar, P

2014-11-21

133

Monte Carlo Simulations of Globular Cluster Evolution. IV. Direct Integration of Strong Interactions  

E-print Network

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.

John M. Fregeau; Frederic A. Rasio

2006-12-06

134

Application of the Monte Carlo integration (MCI) method for calculation of the anisotropy of brachytherapy sources  

NASA Astrophysics Data System (ADS)

Source anisotropy is a very important factor in the brachytherapy quality assurance of high-dose rate (HDR) afterloading stepping sources. If anisotropy is not taken into account then doses received by a brachytherapy patient in certain directions can be in error by a clinically significant amount. Experimental measurements of anisotropy are very labour intensive. We have shown that within acceptable limits of accuracy, Monte Carlo integration (MCI) of a modified Sievert integral (3D generalization) can provide the necessary data within a much shorter time scale than can experiments. Hence MCI can be used for routine quality assurance schedules whenever a new design of HDR or PDR is used for brachytherapy afterloading. Our MCI calculation results are compared with published experimental data and Monte Carlo simulation data for microSelectron and VariSource sources. We have shown not only that MCI offers advantages over alternative numerical integration methods, but also that treating filtration coefficients as radial distance-dependent functions improves Sievert integral accuracy at low energies. This paper also provides anisotropy data for three new sources, one for the microSelectron-HDR and two for the microSelectron-PDR, for which data are currently not available. The information we have obtained in this study can be incorporated into clinical practice.

Baltas, Dimos; Giannouli, Stavroula; Garbi, Anastasia; Diakonos, Fotios; Geramani, Konstantina; Ioannidis, Georgios T.; Tsalpatouros, Alexios; Uzunoglu, Nikolaos; Kolotas, Christos; Zamboglou, Nikolaos

1998-06-01

135

Effect of Nonlinearity in Hybrid Kinetic Monte Carlo-Continuum Models  

SciTech Connect

Recently there has been interest in developing efficient ways to model heterogeneous surface reactions with hybrid computational models that couple a KMC model for a surface to a finite difference model for bulk diffusion in a continuous domain. We consider two representative problems that validate a hybrid method and also show that this method captures the combined effects of nonlinearity and stochasticity. We first validate a simple deposition/dissolution model with a linear rate showing that the KMC-continuum hybrid agrees with both a fully deterministic model and its analytical solution. We then study a deposition/dissolution model including competitive adsorption, which leads to a nonlinear rate, and show that, in this case, the KMC-continuum hybrid and fully deterministic simulations do not agree. However, we are able to identify the difference as a natural result of the stochasticity coming from the KMC surface process. Because KMC captures inherent fluctuations, we consider it to be more realistic than a purely deterministic model. Therefore, we consider the KMC-continuum hybrid to be more representative of a real system.

Balter, Ariel I.; Lin, Guang; Tartakovsky, Alexandre M.

2012-04-23

136

Quantum Monte Carlo dynamics: The stationary phase Monte Carlo path integral calculation of finite temperature time correlation functions  

Microsoft Academic Search

We present a numerically exact procedure for the calculation of an important class of finite temperature quantum mechanical time correlation functions. The present approach is based around the stationary phase Monte Carlo (SPMC) method, a general mathematical tool for the calculation of high dimensional averages of oscillatory integrands. In the present context the method makes possible the direct numerical path

J. D. Doll; Thomas L. Beck; David L. Freeman

1988-01-01

137

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory  

SciTech Connect

This paper provides a review of the hybrid (Monte Carlo/deterministic) radiation transport methods and codes used at the Oak Ridge National Laboratory and examples of their application for increasing the efficiency of real-world, fixed-source Monte Carlo analyses. The two principal hybrid methods are (1) Consistent Adjoint Driven Importance Sampling (CADIS) for optimization of a localized detector (tally) region (e.g., flux, dose, or reaction rate at a particular location) and (2) Forward Weighted CADIS (FW-CADIS) for optimizing distributions (e.g., mesh tallies over all or part of the problem space) or multiple localized detector regions (e.g., simultaneous optimization of two or more localized tally regions). The two methods have been implemented and automated in both the MAVRIC sequence of SCALE 6 and ADVANTG, a code that works with the MCNP code. As implemented, the methods utilize the results of approximate, fast-running 3-D discrete ordinates transport calculations (with the Denovo code) to generate consistent space- and energy-dependent source and transport (weight windows) biasing parameters. These methods and codes have been applied to many relevant and challenging problems, including calculations of PWR ex-core thermal detector response, dose rates throughout an entire PWR facility, site boundary dose from arrays of commercial spent fuel storage casks, radiation fields for criticality accident alarm system placement, and detector response for special nuclear material detection scenarios and nuclear well-logging tools. Substantial computational speed-ups, generally O(102-4), have been realized for all applications to date. This paper provides a brief review of the methods, their implementation, results of their application, and current development activities, as well as a considerable list of references for readers seeking more information about the methods and/or their applications.

Wagner, John C [ORNL; Peplow, Douglas E. [ORNL; Mosher, Scott W [ORNL; Evans, Thomas M [ORNL

2011-01-01

138

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory  

SciTech Connect

This paper provides a review of the hybrid (Monte Carlo/deterministic) radiation transport methods and codes used at the Oak Ridge National Laboratory and examples of their application for increasing the efficiency of real-world, fixed-source Monte Carlo analyses. The two principal hybrid methods are (1) Consistent Adjoint Driven Importance Sampling (CADIS) for optimization of a localized detector (tally) region (e.g., flux, dose, or reaction rate at a particular location) and (2) Forward Weighted CADIS (FW-CADIS) for optimizing distributions (e.g., mesh tallies over all or part of the problem space) or multiple localized detector regions (e.g., simultaneous optimization of two or more localized tally regions). The two methods have been implemented and automated in both the MAVRIC sequence of SCALE 6 and ADVANTG, a code that works with the MCNP code. As implemented, the methods utilize the results of approximate, fast-running 3-D discrete ordinates transport calculations (with the Denovo code) to generate consistent space- and energy-dependent source and transport (weight windows) biasing parameters. These methods and codes have been applied to many relevant and challenging problems, including calculations of PWR ex-core thermal detector response, dose rates throughout an entire PWR facility, site boundary dose from arrays of commercial spent fuel storage casks, radiation fields for criticality accident alarm system placement, and detector response for special nuclear material detection scenarios and nuclear well-logging tools. Substantial computational speed-ups, generally O(10{sup 2-4}), have been realized for all applications to date. This paper provides a brief review of the methods, their implementation, results of their application, and current development activities, as well as a considerable list of references for readers seeking more information about the methods and/or their applications.

Wagner, John C [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Mosher, Scott W [ORNL] [ORNL; Evans, Thomas M [ORNL] [ORNL

2010-01-01

139

A hybrid Markov chain Monte Carlo method for generating permeability fields conditioned to multiwell pressure data and prior information  

SciTech Connect

In order to properly evaluate the uncertainty in reservoir performance predictions, it is necessary to construct and sample the a posteriori probability density functions for the rock property fields. In this work, the a posteriori probability density function is constructed based on prior means and variograms (covariance function) for log-permeability and multiwell pressure data. Within the context of sampling the probability density function, we argue that the notion of equally probable realizations is the wrong paradigm for reservoir characterization. If the simulation of Gaussian random fields with a known variogram is the objective, it is shown that the variogram should not be incorporated directly into the objective function if simulated annealing is applied either to sample the a posteriori probability density function or to estimate a global minimum of the associated objective function. It is shown that the hybrid Markov chain Monte Carlo method provides a way to explore more fully the set of plausible log-permeability fields and does not suffer from the high rejection rates of more standard Markov chain Monte Carlo methods.

Bonet-Cunha, L.; Oliver, D.S.; Redner, R.A. [and others

1996-12-31

140

BAYESIAN ANALYSIS OF ECONOMETRIC TIME SERIES MODELS USING HYBRID INTEGRATION RULES  

Microsoft Academic Search

This paper is concerned with the study of Bayesian inference procedures to commonly used time series models. In particular, the dynamic or state-space models, the time-varying vector autoregressive model and the structural vector autoregressive model are considered in detail. Inference procedures are based on a hybrid integration scheme where state parameters are analytically integrated and hyperparameters are integrated by Markov

Dani Gamerman; Ajax R. B. Moreira

2002-01-01

141

Accelerating execution of the integrated TIGER series Monte Carlo radiation transport codes  

SciTech Connect

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).

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

142

Monte-Carlo experiments on star-cluster induced integrated-galaxy IMF variations  

E-print Network

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.

Carsten Weidner; Pavel Kroupa

2004-09-30

143

Torsional path integral Monte Carlo method for the quantum simulation of large molecules  

NASA Astrophysics Data System (ADS)

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.

Miller, Thomas F.; Clary, David C.

2002-05-01

144

WORM ALGORITHM PATH INTEGRAL MONTE CARLO APPLIED TO THE 3He-4He II SANDWICH SYSTEM  

NASA Astrophysics Data System (ADS)

We present a numerical investigation of the thermal and structural properties of the 3He-4He sandwich system adsorbed on a graphite substrate using the worm algorithm path integral Monte Carlo (WAPIMC) method [M. Boninsegni, N. Prokof'ev and B. Svistunov, Phys. Rev. E74, 036701 (2006)]. For this purpose, we have modified a previously written WAPIMC code originally adapted for 4He on graphite, by including the second 3He-component. To describe the fermions, a temperature-dependent statistical potential has been used. This has proven very effective. The WAPIMC calculations have been conducted in the millikelvin temperature regime. However, because of the heavy computations involved, only 30, 40 and 50 mK have been considered for the time being. The pair correlations, Matsubara Green's function, structure factor, and density profiles have been explored at these temperatures.

Al-Oqali, Amer; Sakhel, Asaad R.; Ghassib, Humam B.; Sakhel, Roger R.

2012-12-01

145

High-Voltage Dielectrophoretic and Magnetophoretic Hybrid Integrated Circuit\\/Microfluidic Chip  

Microsoft Academic Search

A hybrid integrated circuit (IC)\\/microfluidic chip is presented that independently and simultaneously traps and moves microscopic objects suspended in fluid using both electric and magnetic fields. This hybrid chip controls the location of dielectric objects, such as living cells and drops of fluid, on a 60 times 61 array of pixels that are 30 times 38 mum2 in size, each

David Issadore; Thomas Franke; Keith A. Brown; Thomas P. Hunt; Robert M. Westervelt

2009-01-01

146

An Event-based Approach to Integrated Parametric and Discrete Fault Diagnosis in Hybrid Systems  

E-print Network

An Event-based Approach to Integrated Parametric and Discrete Fault Diagnosis in Hybrid Systems.j.daigle@nasa.gov, {xenofon.koutsoukos,gautam.biswas}@vanderbilt.edu Abstract Fault diagnosis is crucial for ensuring the safe for hybrid diagnosis of parametric and discrete faults by incorporating the effects of both types of faults

Daigle, Matthew

147

Integrated main reduction gears for hybrid drive surface ship applications  

Microsoft Academic Search

Hybrid electric drive installations are being considered for back-fit into existing Navy surface combatants, such as the DDG 51 class. Current plans call for adapting an electric rotating machine (ERM) to the existing main reduction gear (MRG). This approach limits the hybrid electric drive capability to limits imposed by MRG design and physical space constraints. This paper reports on an

Dwight Alexander; Tommy Lo; James Bravo; Yakov Fleytman

2011-01-01

148

Integrating Shape and Texture in Deformable Models: from Hybrid Methods to Metamorphs  

E-print Network

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

Huang, Xiaolei

149

Viral Hybrid Vectors for Somatic Integration - Are They the Better Solution?  

PubMed Central

The turbulent history of clinical trials in viral gene therapy has taught us important lessons about vector design and safety issues. Much effort was spent on analyzing genotoxicity after somatic integration of therapeutic DNA into the host genome. Based on these findings major improvements in vector design including the development of viral hybrid vectors for somatic integration have been achieved. This review provides a state-of-the-art overview of available hybrid vectors utilizing viruses for high transduction efficiencies in concert with various integration machineries for random and targeted integration patterns. It discusses advantages but also limitations of each vector system. PMID:21994594

M黷her, Nadine; Noske, Nadja; Ehrhardt, Anja

2009-01-01

150

Extension of the Integrated Tiger Series (ITS) of electron-photon Monte Carlo codes to 100 GeV  

SciTech Connect

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.

Miller, S.G.

1988-08-01

151

Streamline Integration using MPI-Hybrid Parallelism on a Large Multi-Core Architecture  

SciTech Connect

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.

Camp, David; Garth, Christoph; Childs, Hank; Pugmire, Dave; Joy, Kenneth I.

2010-11-01

152

Monte Carlo simulation of small electron fields collimated by the integrated photon MLC  

NASA Astrophysics Data System (ADS)

In this study, a Monte Carlo (MC)-based beam model for an ELEKTA linear accelerator was established. The beam model is based on the EGSnrc Monte Carlo code, whereby electron beams with nominal energies of 10, 12 and 15 MeV were considered. For collimation of the electron beam, only the integrated photon multi-leaf-collimators (MLCs) were used. No additional secondary or tertiary add-ons like applicators, cutouts or dedicated electron MLCs were included. The source parameters of the initial electron beam were derived semi-automatically from measurements of depth-dose curves and lateral profiles in a water phantom. A routine to determine the initial electron energy spectra was developed which fits a Gaussian spectrum to the most prominent features of depth-dose curves. The comparisons of calculated and measured depth-dose curves demonstrated agreement within 1%/1 mm. The source divergence angle of initial electrons was fitted to lateral dose profiles beyond the range of electrons, where the imparted dose is mainly due to bremsstrahlung produced in the scattering foils. For accurate modelling of narrow beam segments, the influence of air density on dose calculation was studied. The air density for simulations was adjusted to local values (433 m above sea level) and compared with the standard air supplied by the ICRU data set. The results indicate that the air density is an influential parameter for dose calculations. Furthermore, the default value of the BEAMnrc parameter 'skin depth' for the boundary crossing algorithm was found to be inadequate for the modelling of small electron fields. A higher value for this parameter eliminated discrepancies in too broad dose profiles and an increased dose along the central axis. The beam model was validated with measurements, whereby an agreement mostly within 3%/3 mm was found.

Mihaljevic, Josip; Soukup, Martin; Dohm, Oliver; Alber, Markus

2011-02-01

153

Equation of state of an interacting Bose gas at finite temperature: A path-integral Monte Carlo study  

SciTech Connect

By using exact path-integral Monte Carlo methods we calculate the equation of state of an interacting Bose gas as a function of temperature both below and above the superfluid transition. The universal character of the equation of state for dilute systems and low temperatures is investigated by modeling the interatomic interactions using different repulsive potentials corresponding to the same s-wave scattering length. The results obtained for the energy and the pressure are compared to the virial expansion for temperatures larger than the critical temperature. At very low temperatures we find agreement with the ground-state energy calculated using the diffusion Monte Carlo method.

Pilati, S.; Giorgini, S. [Dipartimento di Fisica, Universita di Trento and CRS-BEC INFM, I-38050 Povo (Italy); Sakkos, K.; Boronat, J.; Casulleras, J. [Departament de Fisica i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain)

2006-10-15

154

Ring Shaped Motor-Integrated Electric Drive for Hybrid Electric Vehicles  

Microsoft Academic Search

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

Y. Tadros; J. Ranneberg; U. Sch鋐er

155

Integration of LED chip within patch antenna geometry for hybrid FSO/RF communication  

E-print Network

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

Huang, Zhaoran "Rena"

156

Advanced Monte Carlo Methods: General Principles of the Monte  

E-print Network

Advanced Monte Carlo Methods: General Principles of the Monte Carlo Method Prof. Dr. Michael of Monte CarloProf. Dr. Michael Mascagni: Advanced Monte Carlo Methods Slide 2 of 61 Numerical Integration: The Canonical Monte Carlo Application Numerical integration is a simple problem to explain and thoroughly

Mascagni, Michael

157

Integration Profile and Safety of an Adenovirus Hybrid-Vector Utilizing Hyperactive Sleeping Beauty Transposase for Somatic Integration  

PubMed Central

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

Zhang, Wenli; Muck-Hausl, Martin; Wang, Jichang; Sun, Chuanbo; Gebbing, Maren; Miskey, Csaba; Ivics, Zoltan; Izsvak, Zsuzsanna; Ehrhardt, Anja

2013-01-01

158

Path Integral Monte Carlo Calculations of Thermodynamic Properties of Dense Hydrogen-Helium Plasma  

NASA Astrophysics Data System (ADS)

In this work we present new results of ab initio/ calculations of thermodynamic properties of dense hydrogen-helium plasma with helium concentration corresponding to that in the higher layers of the Jovian atmosphere at temperatures from 10^4 K to 2.10^5 K and electron particle densities from 10^20 to 10^24 cm-3. The calculations were made by path-integral Monte Carlo method in a cubical cell using periodic boundary conditions. To correctly take into account exchange effects at high values of the degeneracy parameter we used a special correcting procedure. At temperature higher than 5.10^4 K the calculation results are practically coincides with computations by the equation of state based on the chemical plasma model. However at temperatures 10^4 and 2.10^4 K in the density range from 0.5 to 5 g/cm^3 we found a phase transition region positioned in a good agreement with other theories and the experimentally revealed region of the sharp electrical conductivity rise. Along the isotherm 10^4 K in the density range from 0.01 to 0.2 g/cm^3 we found one more region of bad convergence to the equilibrium state. We also present first simulation results for helium plasma in comparison with other models and experimental data. The authors are grateful to the Russian Science support foundation for financial support of the work.

Filinov, Vladimir; Levashov, Pavel; Bonitz, Michael; Fortov, Vladimir

2005-07-01

159

Monte Carlo simulation studies of lipid order parameter profiles near integral membrane proteins.  

PubMed Central

Monte Carlo simulation techniques have been applied to a statistical mechanical lattice model in order to study the coherence length for the spatial fluctuations of the lipid order parameter profiles around integral membrane proteins in dipalmitoyl phosphatidylcholine bilayers. The model, which provides a detailed description of the pure lipid bilayer main transition, incorporates hydrophobic matching between the lipid and protein hydrophobic thicknesses as a major contribution to the lipid-protein interactions in lipid membranes. The model is studied at low protein-to-lipid ratios. The temperature dependence of the coherence length is found to have a dramatic peak at the phase transition temperature. The dependence on protein circumference as well as hydrophobic length is determined and it is concluded that in some cases the coherence length is much longer than previously anticipated. The long coherence length provides a mechanism for indirect lipid-mediated protein-protein long-range attraction and hence plays an important role in regulating protein segregation. Images FIGURE 5 FIGURE 6 PMID:2009352

Sperotto, M M; Mouritsen, O G

1991-01-01

160

Integration of partial least squares and Monte Carlo gene expression analysis in coronary artery disease  

PubMed Central

Coronary artery disease (CAD) is the most common type of cardiovascular disease and leading cause of mortality worldwide. Microarray technology for gene expression analysis has facilitated the identification of the molecular mechanism that underlies the pathogenesis of CAD. Previous studies have primarily used variance or regression analysis, without considering array specific factors. Thus, the aim of the present study was to investigate the mechanism of CAD using partial least squares (PLS)-based analysis, which was integrated with the Monte Carlo technique. Microarray analysis was performed with a data set of 110 CAD patients and 111 controls obtained from the Gene Expression Omnibus database. A total of 390 dysregulated genes were acquired. Significantly increased representations of dysregulated genes in Gene Ontology items, including transforming growth factor ?-activated receptor activity and acyl-CoA oxidase activity, were identified. Network analysis revealed three hub genes with a degree of >10, including ESR1, ITGA4 and ARRB2. The results of the present study provide novel information on the gene expression signatures of CAD patients and offer further theoretical support for future therapeutic study. PMID:24940402

ZHANG, HUAN; LI, TAO; WU, GUANJI; MA, FENG

2014-01-01

161

MOCABA: a general Monte Carlo-Bayes procedure for improved predictions of integral functions of nuclear data  

E-print Network

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.

Axel Hoefer; Oliver Buss; Maik Hennebach; Michael Schmid; Dieter Porsch

2014-11-12

162

Streamline Integration Using MPI-Hybrid Parallelism on a Large Multicore Architecture  

SciTech Connect

Streamline computation in a very large vector field data set represents a significant challenge due to the nonlocal and data-dependent nature of streamline integration. In this paper, we conduct a study of the performance characteristics of hybrid parallel programming and execution as applied to streamline integration on a large, multicore platform. With multicore processors now prevalent in clusters and 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 over blocks, and present a novel MPI-hybrid algorithm for each approach to compute streamlines. Our findings indicate that the work sharing between cores in the proposed MPI-hybrid parallel implementation results in much improved performance and consumes less communication and I/O bandwidth than a traditional, nonhybrid distributed implementation.

Garth, Christoph [unknown

2011-01-01

163

Streamline integration using MPI-hybrid parallelism on a large multicore architecture.  

PubMed

Streamline computation in a very large vector field data set represents a significant challenge due to the nonlocal and data-dependent nature of streamline integration. In this paper, we conduct a study of the performance characteristics of hybrid parallel programming and execution as applied to streamline integration on a large, multicore platform. With multicore processors now prevalent in clusters and 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 over blocks, and present a novel MPI-hybrid algorithm for each approach to compute streamlines. Our findings indicate that the work sharing between cores in the proposed MPI-hybrid parallel implementation results in much improved performance and consumes less communication and I/O bandwidth than a traditional, nonhybrid distributed implementation. PMID:21885895

Camp, David; Garth, Christoph; Childs, Hank; Pugmire, Dave; Joy, Kenneth I

2011-11-01

164

Enhancing CMOS Using Nanoelectronic Devices: A Perspective on Hybrid Integrated Systems  

Microsoft Academic Search

In this paper, we present a vision for the cointegration of deeply scaled complementary metal-oxide-semiconductor (CMOS) and emerging nanoelectronic devices into CMOS-hybrid systems. These hybrid systems will create new functionality, modality and add value to existing CMOS integrated circuits. We describe several new nanoelectronic devices which may enable new dimensions to traditional CMOS circuits and systems that build on CMOS

David S. Ricketts; James A. Bain; Yi Luo; R. D. Blanton; Kenneth Mai; Gary K. Fedder

2010-01-01

165

Hybrid integrated active antennas, voltage-controlled oscillators and switchable & tunable CPW-slotline filters  

E-print Network

frequency band. The transition enables the incorporation of solid-state devices on slotline to create hybrid switches, modulators, filters, mixers, etc. This transition is unique and differs from previous transitions [29] due to the advantage of providing... HYBRID INTEGRATED ACTIVE ANTENNAS, VOLTAGE-CONTROLLED OSCILLATORS AND SWITCHABLE & TUNABLE CPW-SLOTLINE FILTERS A Thesis by JULIO ANGEL NAVARRO Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment...

Navarro, Julio A

2012-06-07

166

An anthropomorphic phantom integrated EGS4 Monte Carlo code and its application in Compton probe  

Microsoft Academic Search

An EGS4 Monte Carlo Code incorporated with a digitized anthropomorphic phantom is presented. With this Monte Carlo program, new imaging techniques and devices can be investigated accurately under realistic clinical conditions without conducting experiments in living subjects. Imaging quality can be improved by analyzing the image formation procedure with detailed interaction physics. As an example, its application in predicting the

L. Zhangl; S. J. Wilderman; N. H. Clinthorne; W. L. Rogers

2000-01-01

167

Proactive Agriculture: An Integrated Framework for Developing Distributed Hybrid Systems  

Microsoft Academic Search

In this paper we discuss research work that enables the development of hybrid systems consisting of communicating plants and\\u000a artefacts and we investigate methods of creating 搃nterfaces between artefacts and plants in order to enable people to form\\u000a mixed, interacting communities. Our research objective is to develop hardware and software components that enable a seamless\\u000a interaction between plants and artefacts

Christos Goumopoulos; Achilles Kameas; Brendan O扚lynn

2007-01-01

168

Advancements in the path integral Monte Carlo method for many-body quantum systems at finite temperature  

Microsoft Academic Search

Path integral Monte Carlo (PIMC) is a quantum-level simulation method based on a stochastic sampling of the many-body thermal density matrix. Utilizing the imaginary-time formulation of Feynman's sum-over-histories, it includes thermal fluctuations and particle correlations in a natural way. Over the past two decades, PIMC has been applied to the study of the electron gas, hydrogen under extreme pressure, and

Kenneth Paul Esler

2006-01-01

169

Path Integral Monte Carlo Simulations of Solid Molecular Hydrogen Surfaces and Thin HELIUM4 Films on Molecular Hydrogen Substrates  

Microsoft Academic Search

Based on Richard P. Feynman's formulation of quantum mechanics, Path Integral Monte Carlo is a computational ab-initio method to calculate finite temperature equilibrium properties of quantum many-body systems. As input, only fundamental physical constants and pair-potentials are required. We carry out the first ab-initio particle simulations of three related physical systems. First, the bare H _2 substrate is simulated between

Marcus Wagner

1994-01-01

170

Ultra-efficient 10 Gb/s hybrid integrated silicon photonic transmitter and receiver.  

PubMed

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

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

171

Calculation of two-centre two-electron integrals over Slater-type orbitals revisited. I. Coulomb and hybrid integrals  

E-print Network

In this paper, which constitutes the first part of the series, we consider calculation of two-centre Coulomb and hybrid integrals over Slater-type orbitals (STOs). General formulae for these integrals are derived with no restrictions on the values of the quantum numbers and nonlinear parameters. Direct integration over the coordinates of one of the electrons leaves us with the set of overlap-like integrals which are evaluated by using two distinct methods. The first one is based on the transformation to the ellipsoidal coordinates system and the second utilises a recursive scheme for consecutive increase of the angular momenta in the integrand. In both methods simple one-dimensional numerical integrations are used in order to avoid severe digital erosion connected with the straightforward use of the alternative analytical formulae. It is discussed that the numerical integration does not introduce a large computational overhead since the integrands are well-behaved functions, calculated recursively with decent...

Lesiuk, Micha?

2014-01-01

172

Bayesian Parameter Inference by Markov Chain Monte Carlo with Hybrid Fitness Measures: Theory and Test in Apoptosis Signal Transduction Network  

PubMed Central

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

Murakami, Yohei; Takada, Shoji

2013-01-01

173

Design of integrated hybrid silicon waveguide optical gyroscope.  

PubMed

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

Srinivasan, Sudharsanan; Moreira, Renan; Blumenthal, Daniel; Bowers, John E

2014-10-20

174

Hybrid2: combining the three-dimensional hybrid finite element-boundary integral technique for planar multilayered media with the uniform geometrical theory of diffraction  

Microsoft Academic Search

The fully three-dimensional (3-D) hybrid finite element (FE)-boundary integral (BI) technique is extended by further hybridization with the uniform geometrical theory of diffraction (UTD) resulting in a so-called hybrid2 FE-BI-UTD approach. The formulation is capable of modeling arbitrarily shaped strongly inhomogeneous objects together with electrically large obstacles of relatively simple shape within the common environment of a planar-multilayered medium. The

Mudrik Alaydrus; Volkert Hansen; Thomas F. Eibert

2002-01-01

175

Adhesive selection and bonding parameter optimization for hybrid bonding in 3D integration.  

PubMed

Hybrid bonding, an emerging bonding approach with high yield and reliability, can achieve vertical interconnection with adhesive serving reinforcement of the mechanical stability between stacked ICs. To develop metal/adhesive hybrid bonding technology, four kinds of polymer materials, BCB, SU-8, AL-Polymer, and PI, were evaluated as the bonding adhesive. The compatibility between each polymer and metal was investigated, and the application range of each material was established thereof. Furthermore, the scheme of Cu-Sn-Cu interconnection hybridized with patterned BCB was designed and evaluated. Two key factors were discussed and optimized to perform the bonding integrity. The evaluation results and successful metal/adhesive hybrid bonding demonstration are disclosed in the paper. PMID:22754986

Chen, Kuan-Neng; Ko, Cheng-Ta; Hsiao, Zhi-Cheng; Fu, Huan-Chun; Lo, Wei-Chung

2012-03-01

176

Integrated magnetic for hybrid full-bridge three-level LLC resonant converter  

Microsoft Academic Search

A novel hybrid full-bridge (H-FB) three-level (TL) LLC resonant converter with integrated magnetics (IM) is proposed in this paper, it integrates the advantages of the TL converter and the LLC resonant converter, which is very suitable for wide-input-voltage-range applications, such as fuel cell power systems, or high input voltage applications, i.e. HV input converters in wind power system. With magnetic

Koulin Wu; Qianhong Chen; Ke Jin; Xinbo Ruan

2008-01-01

177

Hybrid Integrated Label-Free Chemical and Biological Sensors  

PubMed Central

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

Mehrabani, Simin; Maker, Ashley J.; Armani, Andrea M.

2014-01-01

178

Integration of Plug-In Hybrid Electric Vehicles into energy networks  

Microsoft Academic Search

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

Matthias D. Galus; G. Andersson

2009-01-01

179

Hybrid simultaneous localization and map building: a natural integration of topological and metric  

Microsoft Academic Search

In this paper the metric and topological paradigms are integrated in a hybrid system for both localization and map building. A global topological map connects local metric maps, allowing a compact environment model, which does not require global metric consistency and permits both precision and robustness. Furthermore, the approach handles loops in the environment during automatic mapping by means of

Nicola Tomatis; Illah R. Nourbakhsh; Roland Siegwart

2003-01-01

180

An Integrated Approach to Parametric and Discrete Fault Diagnosis in Hybrid Systems  

E-print Network

An Integrated Approach to Parametric and Discrete Fault Diagnosis in Hybrid Systems Matthew Daigle matthew.j.daigle,xenofon.koutsoukos,gautam.biswas@vanderbilt.edu 1 Fault Diagnosis of Electrical Power Systems Fault diagnosis is crucial for ensuring the safe operation of complex engineering systems. Faults

Daigle, Matthew

181

An Integrated Approach to Parametric and Discrete Fault Diagnosis in Hybrid Systems  

E-print Network

An Integrated Approach to Parametric and Discrete Fault Diagnosis in Hybrid Systems Matthew Daigle {matthew.j.daigle,xenofon.koutsoukos,gautam.biswas}@vanderbilt.edu 1 Fault Diagnosis of Electrical Power Systems Fault diagnosis is crucial for ensuring the safe operation of complex engineering systems. Faults

Koutsoukos, Xenofon D.

182

An HEMT with an integrated on-drain capacitor as basis of an hybrid mixer  

Microsoft Academic Search

This paper reports the study of an HEMT, the characteristic of which is to have a decoupling capacitor directly integrated between its drain and source electrodes. It is shown that, with an appropriate design of this basic filtering element, such a device proves to be efficient as for the realization of hybrid gate mixers. An experimental demonstration of this property

R. Allam; C. Kolanowski; D. Theron; Y. Crosnier

1995-01-01

183

Efficient ethanol recovery from fermentation broths with integrated distillation-vapor permeation hybrid process  

EPA Science Inventory

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...

184

Evaluation of Monte Carlo Electron-Transport Algorithms in the Integrated Tiger Series Codes for Stochastic-Media Simulations  

NASA Astrophysics Data System (ADS)

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.

Franke, Brian C.; Kensek, Ronald P.; Prinja, Anil K.

2014-06-01

185

Integrated Cost and Schedule using Monte Carlo Simulation of a CPM Model - 12419  

SciTech Connect

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

Hulett, David T. [Hulett and Associates, LLC (United States); Nosbisch, Michael R. [Project Time and Cost, Inc. (United States)

2012-07-01

186

Advanced Monte Carlo Methods: Quasi-Monte Carlo  

E-print Network

Advanced Monte Carlo Methods: Quasi-Monte Carlo Prof. Mike Giles mike.giles@maths.ox.ac.uk Oxford University Mathematical Institute QMC 颅 p. 1 #12;Quasi Monte Carlo low discrepancy sequences Koksma 颅 p. 2 #12;Quasi Monte Carlo Standard Monte Carlo approximates high-dimensional hypercube integral [0

Giles, Mike

187

Hybrid III-V on silicon lasers for photonic integrated circuits on silicon  

NASA Astrophysics Data System (ADS)

Silicon photonics is attracting large attention due to the promise of fabricating low-cost, compact circuits that integrate photonic and microelectronic elements. It can address a wide range of applications from short distance data communication to long haul optical transmission. Today, practical Si-based light sources are still missing, despite the recent demonstration of an optically pumped germanium laser. This situation has driven research to the heterogeneous integration of III-V semiconductors on silicon through wafer bonding techniques. This paper reports on recent advances on integrated hybrid InP/SOI lasers and transmitters using a wafer bonding technique made in particular at III-V Lab, France.

Duan, Guang-Hua; Jany, Christophe; Le Liepvre, Alban; Accard, Alain; Lamponi, Marco; Make, Dalila; Kaspar, Peter; Levaufre, Guillaume; Girard, Nils; Lelarge, Fran鏾is; Fedeli, Jean-Marc; Messaoudene, Sonia; Bordel, Damien; Olivier, Segolene

2014-02-01

188

34. Monte Carlo techniques 1 34. MONTE CARLO TECHNIQUES  

E-print Network

34. Monte Carlo techniques 1 34. MONTE CARLO TECHNIQUES Revised September 2011 by G. Cowan (RHUL). Monte Carlo techniques are often the only practical way to evaluate difficult integrals or to sample distribution Most Monte Carlo sampling or integration techniques assume a "random number generator," which

189

34. Monte Carlo techniques 1 34. MONTE CARLO TECHNIQUES  

E-print Network

34. Monte Carlo techniques 1 34. MONTE CARLO TECHNIQUES Revised September 2009 by G. Cowan (RHUL). Monte Carlo techniques are often the only practical way to evaluate difficult integrals or to sample distribution Most Monte Carlo sampling or integration techniques assume a "random number generator," which

190

37. Monte Carlo techniques 1 37. MONTE CARLO TECHNIQUES  

E-print Network

37. Monte Carlo techniques 1 37. MONTE CARLO TECHNIQUES Revised September 2011 by G. Cowan (RHUL). Monte Carlo techniques are often the only practical way to evaluate difficult integrals or to sample distribution Most Monte Carlo sampling or integration techniques assume a "random number generator," which

191

Integration of Neuroscience and Endocrinology in Hybrid PBL Curriculum  

NSDL National Science Digital Library

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 Cushing寐s disease and multiple endocrine neoplastic syndrome type 1.

PhD J. Thomas Cunningham (University of Missouri-Columbia School of Medicine Dept. of Physiology); PhD Ronald H. Freeman (University of Missouri-Columbia School of Medicine Dept. of Physiology); Dr. Michael C. Hosokawa (University of Missouri-Columbia School of Medicine Dept. of Family and Community Medicine)

2001-12-01

192

Integration within the Felsenstein equation for improved Markov chain Monte Carlo methods in population genetics  

Microsoft Academic Search

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

Jody Hey; Rasmus Nielsen

2007-01-01

193

The Markov chain Monte Carlo method: an approach to approximate counting and integration  

Microsoft Academic Search

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

Mark Jerrum; Alistair Sinclair

1996-01-01

194

Bayesian Estimates of Equation System Parameters: An Application of Integration by Monte Carlo  

Microsoft Academic Search

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

Tuen Kloek; Herman K van Dijk

1978-01-01

195

Quantum mechanical single molecule partition function from path integral Monte Carlo simulations  

E-print Network

and a new Monte Carlo estimator for the ratio of partition functions are implemented here to achieve well and at inverse temperature =1/kbT. The values of the Born-Oppenheimer potential V x for reactants and products cm-1 , which roughly corresponds to a CH bond vibration, only the first term ground state

Bell, Alexis T.

196

The theory of hybrid stochastic algorithms  

SciTech Connect

These lectures introduce the family of Hybrid Stochastic Algorithms for performing Monte Carlo calculations in Quantum Field Theory. After explaining the basic concepts of Monte Carlo integration we discuss the properties of Markov processes and one particularly useful example of them: the Metropolis algorithm. Building upon this framework we consider the Hybrid and Langevin algorithms from the viewpoint that they are approximate versions of the Hybrid Monte Carlo method; and thus we are led to consider Molecular Dynamics using the Leapfrog algorithm. The lectures conclude by reviewing recent progress in these areas, explaining higher-order integration schemes, the asymptotic large-volume behaviour of the various algorithms, and some simple exact results obtained by applying them to free field theory. It is attempted throughout to give simple yet correct proofs of the various results encountered. 38 refs.

Kennedy, A.D. (Florida State Univ., Tallahassee, FL (USA). Supercomputer Computations Research Inst.)

1989-11-21

197

Integrated Plasma Simulation of Lower Hybrid Current Drive in Tokamaks  

NASA Astrophysics Data System (ADS)

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).

Bonoli, P. T.; Wright, J. C.; Harvey, R. W.; Batchelor, D. B.; Berry, L. A.; Kessel, C. E.; Jardin, S. C.

2012-03-01

198

Monte Carlo Monte Carlo  

E-print Network

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

199

Multiscale simulation of cluster growth and deposition processes by hybrid model based on direct simulation Monte Carlo method  

Microsoft Academic Search

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

Hiroshi Mizuseki; Kenta Hongo; Yoshiyuki Kawazoe; Luc T. Wille

2002-01-01

200

Two-dimensional core-softened model with water like properties: Monte Carlo and integral equation study  

PubMed Central

Monte Carlo simulations and integral equation theory were used to study the thermodynamics and structure of particles interacting through the smooth version of Stell-Hemmer interaction. We checked the possibility that a fluid with a core-softened potential reproduces anomalies of liquid water such as the density anomaly, the minimum in the isothermal compressibility as a function of temperature, and others. Critical points of the fluid were also determined. We showed that a potential with two characteristic distances is sufficient for the system to exhibit water-like behavior and anomalies, including the famous density maximum. We also showed that some versions of the integral equation theory completely fail to predict structure of such system, while others only predict it qualitatively. PMID:24182057

Urbic, Tomaz

2013-01-01

201

Optimization of hybrid antireflection structure integrating surface texturing and multi-layer interference coating  

NASA Astrophysics Data System (ADS)

The antireflection structure (ARS) for solar cells is categorized to mainly two different techniques, i.e., the surface texturing and the single or multi-layer antireflection interference coating. In this study, we propose a novel hybrid ARS, which integrates moth eye texturing and multi-layer coat, for application to organic photovoltaics (OPVs). Using optical simulations based on the finite-difference time-domain (FDTD) method, we conduct nearly global optimization of the geometric parameters characterizing the hybrid ARS. The proposed optimization algorithm consists of two steps: in the first step, we optimize the period and height of moth eye array, in the absence of multi-layer coating. In the second step, we optimize the whole structure of hybrid ARS by using the solution obtained by the first step as the starting search point. The methods of the simple grid search and the Hooke and Jeeves pattern search are used for global and local searches, respectively. In addition, we study the effects of deviations in the geometric parameters of hybrid ARS from their optimized values. The design concept of hybrid ARS is highly beneficial for broadband light trapping in OPVs.

Kubota, Shigeru; Kanomata, Kensaku; Suzuki, Takahiko; Hirose, Fumihiko

2014-10-01

202

An efficient two-stage Markov chain Monte Carlo method for dynamic data integration  

NASA Astrophysics Data System (ADS)

In this paper, we use a two-stage Markov chain Monte Carlo (MCMC) method for subsurface characterization that employs coarse-scale models. The purpose of the proposed method is to increase the acceptance rate of MCMC by using inexpensive coarse-scale runs based on single-phase upscaling. Numerical results demonstrate that our approach leads to a severalfold increase in the acceptance rate and provides a practical approach to uncertainty quantification during subsurface characterization.

Efendiev, Y.; Datta-Gupta, A.; Ginting, V.; Ma, X.; Mallick, B.

2005-12-01

203

Design of a hybrid fuzzy logic proportional plus conventional integral-derivative controller  

Microsoft Academic Search

Presents approaches to the design of a hybrid fuzzy logic proportional plus conventional integral-derivative (fuzzy P+ID) controller in an incremental form. This controller is constructed by using an incremental fuzzy logic controller in place of the proportional term in a conventional PID controller, By using the bounded-input\\/bounded-output 搒mall gain theorem, the sufficient condition for stability of this controller is derived.

Wei Li

1998-01-01

204

The topological structure of the integral quantum Hall effect in magnetic semiconductor-superconductor hybrids  

NASA Astrophysics Data System (ADS)

An unconventional integer quantum Hall regime was found in magnetic semiconductor-superconductor hybrids. By making use of the decomposition of the gauge potential on a U(1) principal fibre bundle over k-space, we study the topological structure of the integral Hall conductance. It is labeled by the Hopf index ? and the Brouwer degree ?. The Hall conductance topological current and its evolution is discussed.

Ren, Ji-Rong; Zhu, Hui

2009-06-01

205

A novel hybridization of higher order finite element and boundary integral methods for electromagnetic scattering and radiation problems  

Microsoft Academic Search

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

Jian Liu; Jian-Ming Jin

2001-01-01

206

A stochastic Monte Carlo approach to modelling real star cluster evolution - III. Direct integration of three- and four-body interactions  

NASA Astrophysics Data System (ADS)

Spherically symmetric equal-mass star clusters containing a large number of primordial binaries are studied using a hybrid method, consisting of a gas dynamical model for single stars and a Monte Carlo treatment for relaxation of binaries and the setup of close resonant and fly-by encounters of single stars with binaries and binaries with each other (three- and four-body encounters). What differs from our previous work is that each encounter is being integrated using a highly accurate direct few-body integrator which uses regularized variables. Hence we can study the systematic evolution of individual binary orbital parameters (eccentricity, semimajor axis) and differential and total cross-sections for hardening, dissolution or merging of binaries (minimum distance) from a sampling of several tens of thousands of scattering events as they occur in real cluster evolution, including mass segregation of binaries, gravothermal collapse and re-expansion, a binary burning phase and ultimately gravothermal oscillations. For the first time we are able to present empirical cross-sections for eccentricity variation of binaries in close three- and four-body encounters. It is found that a large fraction of three- and four-body encounters result in merging. Eccentricities are generally increased in strong three- and four-body encounters and there is a characteristic scaling law ~ exp (4efin) of the differential cross-section for eccentricity changes, where efin is the final eccentricity of the binary, or harder binary for four-body encounters. Despite these findings the overall eccentricity distribution remains thermal for all binding energies of binaries, which is understood from the dominant influence of resonant encounters. Previous cross-sections obtained by Spitzer and Gao for strong encounters can be reproduced, while for weak encounters non-standard processes such as the formation of hierarchical triples occur.

Giersz, M.; Spurzem, R.

2003-08-01

207

Integrated reluctance position sensor for the self-commutation of a hybrid linear electric actuator Cavarec Pierre-Emmanuel  

E-print Network

Integrated reluctance position sensor for the self-commutation of a hybrid linear electric actuator-commutation of a hybrid linear electric actuator Cavarec Pierre-Emmanuel, Hamid Ben Ahmed, Bernard Multon LESIR Britany branch Campus de Ker Lann 35170 Bruz France Cavarec@bretagne.ens-cachan.fr Keywords: Actuators, Highly

Paris-Sud XI, Universit茅 de

208

Integrating emerging topics through online team design in a hybrid communication networks course: Interaction patterns and impact  

E-print Network

Integrating emerging topics through online team design in a hybrid communication networks course Abstract An important challenge in the introductory communication networks course in electrical students with experiences in online collaboration, which is common in the engineering workplace

Reisslein, Martin

209

Monte Carlo Basics 1 Introduction  

E-print Network

1 Monte Carlo Basics 搂1 Introduction WHAT IS THE MONTE CARLO METHOD? 路 Monte Carlo (MC) method. Multidimensional integrations (e.g., statistical mechanics in physics); 2. Simulation of stochastic natural phenomena (e.g., stock price). 路 Numerical vs. MC Integration The simplest numerical integration of a one

Southern California, University of

210

Design of a hybrid computational fluid dynamics-monte carlo radiation transport methodology for radioactive particulate resuspension studies.  

PubMed

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

Ali, Fawaz; Waller, Ed

2014-10-01

211

Mercedes朆enz water molecules near hydrophobic wall: Integral equation theories vs Monte Carlo simulations  

PubMed Central

Associative version of Henderson-Abraham-Barker theory is applied for the study of Mercedes朆enz 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

Urbic, T.; Holovko, M. F.

2011-01-01

212

Advances in hybrid finite element - boundary integral - multilevel fast multipole - uniform geometrical theory of diffraction method  

NASA Astrophysics Data System (ADS)

Numerical modeling of problems including composite metallic/dielectric objects with arbitrary shapes and electrically large conducting objects within a common environment is performed in an optimum way with the recently developed powerful hybrid numerical method, which combines the Finite Element Boundary Integral (FEBI) method and the Multilevel Fast Multipole Method (MLFMM) with the Uniform Geometrical Theory of Diffraction (UTD), giving full electromagnetic coupling between all involved objects. In this contribution, the hybrid FEBI-MLFMM-UTD method is extended to double diffracted fields on pairs of straight metallic edges, formulated with the hard and soft scalar diffraction coefficients of UTD. The diffraction points on each pair of edges are determined by an iterative three-dimensional parametric realization of the generalized Fermat's principle. The divergence factor of the double diffracted field is computed by multiplying the appropriate divergence factors of the single diffracted UTD fields on each edge for the particular case. Thereby, the ray caustic distance of the diffracted field at the second edge is determined by linear interpolation between the radii of curvature in the two principal planes of the incident astigmatic ray tube. Further, fast near-field computation in the postprocessing stage of the hybrid method is extended in each translation domain to ray optical contributions due to the presence of electrically large objects, according to the hybridization of MLFMM with UTD. Formulations and numerical results will be presented.

Tzoulis, A.; Eibert, T. F.

2007-06-01

213

Path-integral representation for quantum spin models: Application to the quantum cavity method and Monte Carlo simulations  

NASA Astrophysics Data System (ADS)

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.

Krzakala, Florent; Rosso, Alberto; Semerjian, Guilhem; Zamponi, Francesco

2008-10-01

214

Mercury + VisIt: Integration of a Real-Time Graphical Analysis Capability into a Monte Carlo Transport Code  

SciTech Connect

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.

O'Brien, M J; Procassini, R J; Joy, K I

2009-03-09

215

High-performance binary blazed grating coupler used in silicon-based hybrid photodetector integration  

NASA Astrophysics Data System (ADS)

An efficient and high-performance binary blazed grating coupler was designed based on silicon-on-insulator (SOI) used for silicon-based hybrid photodetector integration in an arrayed waveguide grating demodulation integrated microsystem. A relatively high coupling efficiency was obtained to optimize mode matching by the finite-difference time-domain method by choosing appropriate grating parameters, including period, etching depth, and fill factor. Coupling efficiency output at 1550 nm for the TE mode reached 68%. This value was >60% in the wavelength range of 1450 to 1600 nm, specifically 71.4% around 1478 nm. An InP/InGaAs photodetector and SOI wafer were integrated by using benzocyclobutene (BCB) bonding. When the thickness of the BCB bonding layer was 440 nm, power absorption efficiency at 1550 nm for the TE mode reached 78.5%, whereas efficiency reached 81.8% around 1475 nm.

Li, Hongqiang; Liu, Yu; Miao, Chunjiao; Zhang, Meiling; Zhou, Wenqian; Tang, Chunxiao; Li, Enbang

2014-09-01

216

Integrated Tiger Series of electron/photon Monte Carlo transport codes: a user's guide for use on IBM mainframes  

SciTech Connect

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.

Kirk, B.L.

1985-12-01

217

Thermodynamics of the quark-gluon plasma at finite chemical potential: color path integral Monte Carlo results  

E-print Network

Based on the constituent quasiparticle model of the quark-gluon plasma (QGP), color quantum path-integral Monte-Carlo (PIMC) calculations of the thermodynamic properties of the QGP are performed. We extend our previous zero chemical potential simulations to the QGP at finite baryon chemical potential. The results indicate that color PIMC can be applied not only above the QCD critical temperature $T_c$ but also below $T_c$. Besides reproducing the lattice equation of state our approach yields also valuable additional insight into the internal structure of the QGP, via the pair distribution functions of the various quasiparticles. In particular, the pair distribution function of gluons reflects the existence of gluon-gluon bound states at low temperatures and $\\mu=175$ MeV, i.e. glueballs, while meson-like bound states are not found.

V. S. Filinov; M. Bonitz; Y. B. Ivanov; M. Ilgenfritz; V. E. Fortov

2014-08-25

218

Thermodynamics of the quark-gluon plasma at finite chemical potential: color path integral Monte Carlo results  

E-print Network

Based on the constituent quasiparticle model of the quark-gluon plasma (QGP), color quantum path-integral Monte-Carlo (PIMC) calculations of the thermodynamic properties of the QGP are performed. We extend our previous zero chemical potential simulations to the QGP at finite baryon chemical potential. The results indicate that color PIMC can be applied not only above the QCD critical temperature $T_c$ but also below $T_c$. Besides reproducing the lattice equation of state our approach yields also valuable additional insight into the internal structure of the QGP, via the pair distribution functions of the various quasiparticles. In particular, the pair distribution function of gluons reflects the existence of gluon-gluon bound states at low temperatures and $\\mu=175$ MeV, i.e. glueballs, while meson-like bound states are not found.

Filinov, V S; Ivanov, Y B; Ilgenfritz, M; Fortov, V E

2014-01-01

219

Implementing an Integrated Learning System for Hybrid Vehicle Technology: Supporting the Green Transportation  

NSDL National Science Digital Library

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.

College, Wayne S.

220

Improved estimators for the self-energy and vertex function in hybridization-expansion continuous-time quantum Monte Carlo simulations  

NASA Astrophysics Data System (ADS)

We propose efficient measurement procedures for the self-energy and vertex function of the Anderson impurity model within the hybridization expansion continuous-time quantum Monte Carlo algorithm. The method is based on the measurement of higher-order correlation functions related to the quantities being sought through the equation of motion, a technique previously introduced in the numerical renormalization-group context. For the case of interactions of density-density type, the additional correlators can be obtained at essentially no additional computational cost. In combination with a recently introduced method for filtering the Monte Carlo noise using a representation in terms of orthogonal polynomials, we obtain data with unprecedented accuracy. This leads to an enhanced stability in analytical continuations of the self-energy or in two-particle-based theories such as the dual fermion approach. As an illustration of the method we reexamine the previously reported spin-freezing and high-spin to low-spin transitions in a two-orbital model with density-density interactions. In both cases, the vertex function undergoes significant changes, which suggests significant corrections to the dynamical mean-field solutions in dual fermion calculations.

Hafermann, Hartmut; Patton, Kelly R.; Werner, Philipp

2012-05-01

221

Integration hybride de transistors a un electron sur un noeud technologique CMOS  

NASA Astrophysics Data System (ADS)

This study deals with the hybrid integration of single electron transistors (SET) on a CMOS technology nod. SET devices possess a high potential, especially regarding energy efficiency, but aren't fit to completely replace CMOS components in electrical circuits. However, this problem can be solved through hybrid combination of SETs and MOS, leading to very low operating power circuits, and high integration density. This thesis investigates the use of the nanodamascene process, developed by C. Dubuc, for back-end-of-line (BEOL) SET fabrication, meaning creation of SETs in the oxide encapsulating CMOS devices. The assets the nanodamascene process presents are quite interesting: fabrication of SETs with a large operation margin, high repeatability, and potential for BEOL fabrication. This last point, in particular, makes this process promising. Indeed, it opens the path to the fabrication of numerous layers of SETs, stacked one upon the other, and forming 3D circuits, created on top of 2D CMOS layer. Thus a high gain to existing CMOS wafers could be generated. Devices created through the use of the nanodamascene process, adapted for BEOL SET fabrication, are presented. Limits and improvement perspectives of the technique's transfer are discussed. Electrical characterizations of the devices are also presented. They have demonstrated the created devices functionality, thus validating the successful adaption of the nanodamascene process. They have also allowed for the identification of numerous traps located at the heart of fabricated devices. Fabricated SET devices potential for hybrid SET-CMOS circuits was studied through simulations. Possible architectures showing good potential for early hybrid circuits' realization were identified. Keywords: MOSFET, single electron transistor (SET), nanotechnology, microfabrication, nanodamascene, electrical characterization.

Jouvet, Nicolas

222

Integration of Multisensor Hybrid Reasoners to Support Personal Autonomy in the Smart Home  

PubMed Central

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

Valero, Miguel 羘gel; Bravo, Jos; Chamizo, Juan Manuel Garc韆; L髉ez-de-Ipi馻, Diego

2014-01-01

223

Draft of M2 Report on Integration of the Hybrid Hydride Model into INL抯 MBM Framework for Review  

SciTech Connect

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 慼ydrogen 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.

Tikare, Veena; Weck, Philippe F.; Schultz, Peter A.; Clark, Blythe; Michael Glazoff; Eric Homer

2014-07-01

224

Integration of Hybrid Fibre Radio and IEEE 802.11 WLAN network Kenneth K L. Ho and J. E. Mitchell  

E-print Network

Integration of Hybrid Fibre Radio and IEEE 802.11 WLAN network Kenneth K L. Ho and J. E. Mitchell in deploying IEEE 802.11 wireless local access network (WLAN) through integration with HFR. We will discuss its, and a requirement suitable for a high-speed technology like WLAN. Outdoor hotspots: IEEE 802.11 WLAN tends to have

Haddadi, Hamed

225

Hybrid III/V silicon photonic source with integrated 1D free-space beam steering.  

PubMed

A chip-scale optical source with integrated beam steering is demonstrated. The chip was fabricated using the hybrid silicon platform and incorporates an on-chip laser, waveguide splitter, amplifiers, phase modulators, and surface gratings to comprise an optical phased array with beam steering across a 12 field of view in one axis. Tuning of the phased array is used to achieve 1.8(steered axis)0.6(nonsteered axis) beam width with 7燿B background suppression for arbitrary beam direction within the field of view. PMID:23073429

Doylend, J K; Heck, M J R; Bovington, J T; Peters, J D; Davenport, M L; Coldren, L A; Bowers, J E

2012-10-15

226

Progress of Integral Experiments in Benchmark Fission Assemblies for a Blanket of Hybrid Reactor  

NASA Astrophysics Data System (ADS)

This article describes recent progress in integral neutronics experiments in benchmark fission assemblies for the blanket design in a hybrid reactor. The spherical assemblies consist of three layers of depleted uranium shells and several layers of polyethylene shells, separately. In the assemblies with centralizing the D-T neutron source, the plutonium production rates, uranium fission rates and leakage neutron spectra are measured. The measured results are compared to the calculated ones with the MCNP-4B code and ENDF/B-VI library data, available.

Liu, R.; Zhu, T. H.; Yan, X. S.; Lu, X. X.; Jiang, L.; Wang, M.; Han, Z. J.; Wen, Z. W.; Lin, J. F.; Yang, Y. W.

2014-04-01

227

Organic朓norganic Eu3+/Tb3+ codoped hybrid films for temperature mapping in integrated circuits  

PubMed Central

The continuous decrease on the geometric size of electronic devices and integrated circuits generates higher local power densities and localized heating problems that cannot be characterized by conventional thermographic techniques. Here, a self-referencing intensity-based molecular thermometer involving a di-ureasil organic-inorganic hybrid thin film co-doped with Eu3+ and Tb3+ tris (?-diketonate) chelates is used to obtain the temperature map of a FR4 printed wiring board with spatio-temporal resolutions of 0.42 ?m/4.8 ms. PMID:24790938

Brites, Carlos D. S.; Lima, Patr韈ia P.; Silva, Nuno J. O.; Mill醤, Angel; Amaral, Vitor S.; Palacio, Fernando; Carlos, Lu韘 D.

2013-01-01

228

A hybrid multiscale Monte Carlo algorithm (HyMSMC) to cope with disparity in time scales and species populations in intracellular networks  

PubMed Central

Background The fundamental role that intrinsic stochasticity plays in cellular functions has been shown via numerous computational and experimental studies. In the face of such evidence, it is important that intracellular networks are simulated with stochastic algorithms that can capture molecular fluctuations. However, separation of time scales and disparity in species population, two common features of intracellular networks, make stochastic simulation of such networks computationally prohibitive. While recent work has addressed each of these challenges separately, a generic algorithm that can simultaneously tackle disparity in time scales and population scales in stochastic systems is currently lacking. In this paper, we propose the hybrid, multiscale Monte Carlo (HyMSMC) method that fills in this void. Results The proposed HyMSMC method blends stochastic singular perturbation concepts, to deal with potential stiffness, with a hybrid of exact and coarse-grained stochastic algorithms, to cope with separation in population sizes. In addition, we introduce the computational singular perturbation (CSP) method as a means of systematically partitioning fast and slow networks and computing relaxation times for convergence. We also propose a new criteria of convergence of fast networks to stochastic low-dimensional manifolds, which further accelerates the algorithm. Conclusion We use several prototype and biological examples, including a gene expression model displaying bistability, to demonstrate the efficiency, accuracy and applicability of the HyMSMC method. Bistable models serve as stringent tests for the success of multiscale MC methods and illustrate limitations of some literature methods. PMID:17524148

Samant, Asawari; Ogunnaike, Babatunde A; Vlachos, Dionisios G

2007-01-01

229

Solution of the Nonlinear Mixed Volterra-Fredholm Integral Equations by Hybrid of Block-Pulse Functions and Bernoulli Polynomials  

PubMed Central

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

Mashayekhi, S.; Razzaghi, M.; Tripak, O.

2014-01-01

230

Finding Linear Dependencies in Integration-By-Parts Equations: A Monte Carlo Approach  

E-print Network

The reduction of a large number of scalar integrals to a small set of master integrals via Laporta's algorithm is common practice in multi-loop calculations. It is also a major bottleneck in terms of running time and memory consumption. It involves solving a large set of linear equations where many of the equations are linearly dependent. We propose a simple algorithm that eliminates all linearly dependent equations from a given system, reducing the time and space requirements of a subsequent run of Laporta's algorithm.

Philipp Kant

2014-02-11

231

hybrid\\scriptsize{{MANTIS}}: a CPU-GPU Monte Carlo method for modeling indirect x-ray detectors with columnar scintillators  

NASA Astrophysics Data System (ADS)

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.

Sharma, Diksha; Badal, Andreu; Badano, Aldo

2012-04-01

232

ITS Version 6 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.  

SciTech Connect

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.

Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

2008-04-01

233

Servo-integrated patterned media by hybrid directed self-assembly.  

PubMed

A hybrid directed self-assembly approach is developed to fabricate unprecedented servo-integrated bit-patterned media templates, by combining sphere-forming block copolymers with 5 teradot/in.(2) resolution capability, nanoimprint and optical lithography with overlay control. Nanoimprint generates prepatterns with different dimensions in the data field and servo field, respectively, and optical lithography controls the selective self-assembly process in either field. Two distinct directed self-assembly techniques, low-topography graphoepitaxy and high-topography graphoepitaxy, are elegantly integrated to create bit-patterned templates with flexible embedded servo information. Spinstand magnetic test at 1 teradot/in.(2) shows a low bit error rate of 10(-2.43), indicating fully functioning bit-patterned media and great potential of this approach for fabricating future ultra-high-density magnetic storage media. PMID:25380228

Xiao, Shuaigang; Yang, Xiaomin; Steiner, Philip; Hsu, Yautzong; Lee, Kim; Wago, Koichi; Kuo, David

2014-11-25

234

Integration of plug-in hybrid electric vehicles (PHEV) with grid connected residential photovoltaic energy systems  

NASA Astrophysics Data System (ADS)

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

Nagarajan, Adarsh; Shireen, Wajiha

2013-06-01

235

Quantum partition functions of composite particles in a hydrogen-helium plasma via path integral Monte Carlo  

NASA Astrophysics Data System (ADS)

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.

Wendland, D.; Ballenegger, V.; Alastuey, A.

2014-11-01

236

Extraction of diffuse correlation spectroscopy flow index by integration of Nth-order linear model with Monte Carlo simulation  

SciTech Connect

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; 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

237

A hybrid fuzzy integral decision-making model for locating manufacturing centers in China: A case study  

Microsoft Academic Search

This study presents a hybrid fuzzy integral decision-making model that integrates factor analysis, interpretive structural modeling, Markov chain, fuzzy integral and the simple additive weighted method for selecting locations of high-tech manufacturing centers in China. The analytical results of this case study demonstrate the feasibility of the proposed model for solving fuzzy multiple attribute decision-making problems, especially when criteria are

Cheng-min Feng; Pei-ju Wu; Kai-chieh Chia

2010-01-01

238

Quantifying Integrated Hydrologic Model Input and Parameter Uncertainty using Markov Chain Monte Carlo Simulations  

NASA Astrophysics Data System (ADS)

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.

Rajagopal, S.; Huntington, J. L.; Niswonger, R. G.; Reeves, M.; Pohll, G.

2012-12-01

239

Fully integrated hybrid silicon free-space beam steering source with 32-channel phased array  

NASA Astrophysics Data System (ADS)

Free-space beam steering using optical phased arrays is a promising method for implementing free-space communication links and Light Detection and Ranging (LIDAR) without the sensitivity to inertial forces and long latencies which characterize moving parts. Implementing this approach on a silicon-based photonic integrated circuit adds the additional advantage of working with highly developed CMOS processing techniques. In this work we discuss our progress in the development of a fully integrated 32 channel PIC with a widely tunable diode laser, a waveguide phased array, an array of fast phase modulators, an array of hybrid III-V/silicon amplifiers, surface gratings, and a graded index lens (GRIN) feeding an array of photodiodes for feedback control. The PIC has been designed to provide beam steering across a 15皒5 field of view with 0.6皒0.6 beam width and background peaks suppressed 15 dB relative to the main lobe within the field of view for arbitrarily chosen beam directions. Fabrication follows the hybrid silicon process developed at UCSB with modifications to incorporate silicon diodes and a GRIN lens.

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.

2014-03-01

240

Top Quark Mass Measurement Using a Matrix Element Method with Quasi-Monte Carlo Integration  

E-print Network

We report an updated measurement of the top quark mass obtained from ppbar collisions at sqrt(s) = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. Our measurement uses a matrix element integration method to obtain a signal likelihood, with a neural network used to identify background events and a likelihood cut applied to reduce the effect of badly reconstructed events. We use a 2.7 fb^-1 sample and observe 422 events passing all of our cuts. We find m_t = 172.2 +/- 1.0 (stat.) +/- 0.9 (JES) +/- 1.0 (syst.) GeV/c^2, or m_t = 172.2 +/- 1.7 (total) GeV/c^2.

Paul J. Lujan; for the CDF Collaboration

2008-10-21

241

Extrapolation to infinite Trotter number in path-integral Monte Carlo simulations of solid-state systems  

NASA Astrophysics Data System (ADS)

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.

Cuccoli, Alessandro; Macchi, Alessandro; Pedrolli, Gaia; Tognetti, Valerio; Vaia, Ruggero

1995-05-01

242

Accurate determination of the Gibbs energy of Cu-Zr melts using the thermodynamic integration method in Monte Carlo simulations.  

PubMed

The design of multicomponent alloys used in different applications based on specific thermo-physical properties determined experimentally or predicted from theoretical calculations is of major importance in many engineering applications. A procedure based on Monte Carlo simulations (MCS) and the thermodynamic integration (TI) method to improve the quality of the predicted thermodynamic properties calculated from classical thermodynamic calculations is presented in this study. The Gibbs energy function of the liquid phase of the Cu-Zr system at 1800 K has been determined based on this approach. The internal structure of Cu-Zr melts and amorphous alloys at different temperatures, as well as other physical properties were also obtained from MCS in which the phase trajectory was modeled by the modified embedded atom model formalism. A rigorous comparison between available experimental data and simulated thermo-physical properties obtained from our MCS is presented in this work. The modified quasichemical model in the pair approximation was parameterized using the internal structure data obtained from our MCS and the precise Gibbs energy function calculated at 1800 K from the TI method. The predicted activity of copper in Cu-Zr melts at 1499 K obtained from our thermodynamic optimization was corroborated by experimental data found in the literature. The validity of the amplitude of the entropy of mixing obtained from the in silico procedure presented in this work was analyzed based on the thermodynamic description of hard sphere mixtures. PMID:21895194

Harvey, J-P; Gheribi, A E; Chartrand, P

2011-08-28

243

Path Integral Monte Carlo study confirms a highly ordered snowball in $^4$He nanodroplets doped with an Ar$^+$ ion  

E-print Network

By means of the exact Path Integral Monte Carlo method we have performed a detailed microscopic study of 4He nanodroplets doped with an argon ion, Ar$^+$, at $T=0.5$ K. We have computed density profiles, energies, dissociation energies and characterized the local order around the ion for nanodroplets with a number of 4He atoms ranging from 10 to 64 and also 128. We have found the formation of a stable solid structure around the ion, a "snowball", consisting of 3 concentric shells in which the 4He atoms are placed on at the vertices of platonic solids: the first inner shell is an icosahedron (12 atoms); the second one is a dodecahedron with 20 atoms placed on the faces of the icosahedron of the first shell; the third shell is again an icosahedron composed of 12 atoms placed on the faces of the dodecahedron of the second shell. The "magic numbers" implied by this structure, 12, 32 and 44 helium atoms, have been observed in a recent experimental study [Bartl et al, J. Phys. Chem. A 118, 2014] of these complexes;...

Tramonto, Filippo; Nava, Marco; Galli, Davide E

2014-01-01

244

A hybrid kinetic Monte Carlo method for simulating silicon films grown by plasma-enhanced chemical vapor deposition  

NASA Astrophysics Data System (ADS)

We present a powerful kinetic Monte Carlo (KMC) algorithm that allows one to simulate the growth of nanocrystalline silicon by plasma enhanced chemical vapor deposition (PECVD) for film thicknesses as large as several hundreds of monolayers. Our method combines a standard n-fold KMC algorithm with an efficient Markovian random walk scheme accounting for the surface diffusive processes of the species involved in PECVD. These processes are extremely fast compared to chemical reactions, thus in a brute application of the KMC method more than 99% of the computational time is spent in monitoring them. Our method decouples the treatment of these events from the rest of the reactions in a systematic way, thereby dramatically increasing the efficiency of the corresponding KMC algorithm. It is also making use of a very rich kinetic model which includes 5 species (H, SiH3, SiH2, SiH, and Si2H5) that participate in 29 reactions. We have applied the new method in simulations of silicon growth under several conditions (in particular, silane fraction in the gas mixture), including those usually realized in actual PECVD technologies. This has allowed us to directly compare against available experimental data for the growth rate, the mesoscale morphology, and the chemical composition of the deposited film as a function of dilution ratio.

Tsalikis, D. G.; Baig, C.; Mavrantzas, V. G.; Amanatides, E.; Mataras, D.

2013-11-01

245

lordif: An R Package for Detecting Differential Item Functioning Using Iterative Hybrid Ordinal Logistic Regression/Item Response Theory and Monte Carlo Simulations  

PubMed Central

Logistic regression provides a flexible framework for detecting various types of differential item functioning (DIF). Previous efforts extended the framework by using item response theory (IRT) based trait scores, and by employing an iterative process using group杝pecific item parameters to account for DIF in the trait scores, analogous to purification approaches used in other DIF detection frameworks. The current investigation advances the technique by developing a computational platform integrating both statistical and IRT procedures into a single program. Furthermore, a Monte Carlo simulation approach was incorporated to derive empirical criteria for various DIF statistics and effect size measures. For purposes of illustration, the procedure was applied to data from a questionnaire of anxiety symptoms for detecting DIF associated with age from the Patient朢eported Outcomes Measurement Information System. PMID:21572908

Choi, Seung W.; Gibbons, Laura E.; Crane, Paul K.

2011-01-01

246

Automatic on-chip RNA-DNA hybridization assay with integrated phase change microvalves  

NASA Astrophysics Data System (ADS)

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.

Weng, Xuan; Jiang, Hai; Wang, Junsheng; Chen, Shu; Cao, Honghe; Li, Dongqing

2012-07-01

247

Research of Current Control Strategy of Hybrid Active Power Filter Based on Fuzzy Recursive Integral PI Control Algorithm  

NASA Astrophysics Data System (ADS)

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.

Tang, Zhong; Liao, Daifa

248

A hybrid design methodology for structuring an Integrated Environmental Management System (IEMS) for shipping business.  

PubMed

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

Celik, Metin

2009-03-01

249

Image restoration of hybrid time delay and integration camera system with residual motion  

NASA Astrophysics Data System (ADS)

In this paper, we present a hybrid system for time delay and integration (TDI) image restoration. Images are degraded by residual motion, which distorts and blurs the TDI images during exposures and excludes the along-track scanning motion. The motion trajectory is estimated from the image sequence captured by an auxiliary high-speed camera. In order to make the estimated results less sensitive to the imaging conditions and noise, a new method based on cross-correlation is introduced for motion estimation. Then geometric distortion of the TDI image is removed by choosing the correct blurred block according to the central of the corresponding motion trajectory and the final image is restored row by row with the Richardson-Lucy algorithm. Simulated and experimental results are given to prove the effectiveness of our system.

Zheng, Zhenzhen; Wu, Jiagu; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

2011-06-01

250

Structural Heterogeneity and Quantitative FRET Efficiency Distributions of Polyprolines through a Hybrid Atomistic Simulation and Monte Carlo Approach  

PubMed Central

F鰎ster 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

Hoefling, Martin; Lima, Nicola; Haenni, Dominik; Seidel, Claus A. M.; Schuler, Benjamin; Grubm黮ler, Helmut

2011-01-01

251

High-Performance Hybrid Complementary Logic Inverter through Monolithic Integration of a MEMS Switch and an Oxide TFT.  

PubMed

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

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

2014-11-22

252

Highly efficient electricity generation from biomass by integration and hybridization with combined cycle gas turbine (CCGT) plants for natural gas  

Microsoft Academic Search

Integration\\/co-firing with existing fossil fuel plants could give near term highly efficient and low cost power production from biomass. This paper presents a techno-economical analysis on options for integrating biomass thermal conversion (optimized for local resources ?50燤Wth) with existing CCGT (combined cycle gas turbine) power plants (8001400燤Wth). Options include hybrid combined cycles (HCC), indirect gasification of biomass and simple cycle

Erik Pihl; Stefan Heyne; Henrik Thunman; Filip Johnsson

2010-01-01

253

Film-level hybrid integration of AlGaAs laser diode with glass waveguide on Si substrate  

Microsoft Academic Search

A ridge-waveguide AlGaAs laser diode (LD) was integrated with a SiO2-Ta2O5 embedded waveguide on a Si substrate by using a film-level hybrid integration technique of semiconductor epitaxial film. CW operation of the LD was achieved at room temperature. The LD-waveguide butt-coupling loss was 9 dB, and the loss due to misalignment was estimated at 3 dB, which corresponds to a

Masahiro Yanagisawa; Hiroshi Terui; Keizou Shuto; Tetsuo Miya; Morio Kobayashi

1992-01-01

254

Integration of a particle-particle-particle-mesh algorithm with the ensemble Monte Carlo method for the simulation of ultra-small semiconductor devices  

Microsoft Academic Search

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

Carl J. Wordelman; Umberto Ravaioli

2000-01-01

255

Validation of columnar CsI x-ray detector responses obtained with hybridMANTIS, a CPU-GPU Monte Carlo code for coupled x-ray, electron, and optical transport  

SciTech Connect

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.

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

256

Hybrid Integrated EMC filter for CM and DM EMC Suppression in a DC-DC Power converter  

Microsoft Academic Search

This work is focused on the design and the realization of an integrated EMI filter embedded in an aircraft power supply. The first part is dedicated to the design of the EMI filter, based on the converter EMC model. This initial step enables to define the electrical structure of the filter and the components values; a hybrid solution (active plus

Marwan Ali; Eric Laboure; Bertrand Revol; Cyrille Gautier

2012-01-01

257

Integrated Array-Comparative Genomic Hybridization and Expression Array Profiles Identify Clinically Relevant Molecular Subtypes of Glioblastoma  

Microsoft Academic Search

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,

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

258

Using a hybrid Monte Carlo/Genetic Algorithm Slip Estimator to produce high resolution models of paleoearthquakes from geodetic data  

NASA Astrophysics Data System (ADS)

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.

Lindsay, A.; McCloskey, J.; Nalbant, S. S.; Simao, N.; Murphy, S.; NicBhloscaidh, M.; Steacy, S.

2013-12-01

259

A Massively Parallel Hybrid Dusty-Gasdynamics and Kinetic Direct Simulation Monte Carlo Model for Planetary Applications  

NASA Technical Reports Server (NTRS)

In order to understand the global structure, dynamics, and physical and chemical processes occurring in the upper atmospheres, exospheres, and ionospheres of the Earth, the other planets, comets and planetary satellites and their interactions with their outer particles and fields environs, it is often necessary to address the fundamentally non-equilibrium aspects of the physical environment. These are regions where complex chemistry, energetics, and electromagnetic field influences are important. Traditional approaches are based largely on hydrodynamic or magnetohydrodynamic (MHD) formulations and are very important and highly useful. However, these methods often have limitations in rarefied physical regimes where the molecular collision rates and ion gyrofrequencies are small and where interactions with ionospheres and upper neutral atmospheres are important. At the University of Michigan we have an established base of experience and expertise in numerical simulations based on particle codes which address these physical regimes. The Principal Investigator, Dr. Michael Combi, has over 20 years of experience in the development of particle-kinetic and hybrid kinetichydrodynamics models and their direct use in data analysis. He has also worked in ground-based and space-based remote observational work and on spacecraft instrument teams. His research has involved studies of cometary atmospheres and ionospheres and their interaction with the solar wind, the neutral gas clouds escaping from Jupiter s moon Io, the interaction of the atmospheres/ionospheres of Io and Europa with Jupiter s corotating magnetosphere, as well as Earth s ionosphere. This report describes our progress during the year. The contained in section 2 of this report will serve as the basis of a paper describing the method and its application to the cometary coma that will be continued under a research and analysis grant that supports various applications of theoretical comet models to understanding the inner comae of comets (grant NAGS- 13239 from the Planetary Atmospheres program).

Combi, Michael R.

2004-01-01

260

Hybrid Model Integrating Immunohistochemistry and Expression Profiling for the Classification of Carcinomas of Unknown Primary Site  

PubMed Central

Identification of the site of origin for 憁alignancy with unknown primary remains a challenge for modern pathology. Correct diagnosis is critical to defining the most beneficial treatment for the patient. Standard pathological approaches combine morphology and immunohistochemical (IHC) studies to first subclassify cytokeratin-positive carcinomas into adenocarcinoma, squamous cell carcinoma, neuroendocrine carcinoma, and urothelial carcinoma. Subsequently, organ-specific IHC-markers, if available, are used to assign the tumor's primary site of origin. Previous gene expression classifiers have shown promise in tumor classification but cannot readily be integrated into standard practice because they ignore the algorithmic hierarchy used by pathologists. Here we present a novel hybrid approach integrating a hierarchy of gene expression classifiers into the algorithmic method used with IHC. In this method, a tumor is initially assigned to one of the carcinoma subclasses by the top tier classifier. Dependent on initial classification, one of three second-tier classifiers assign primary site resulting in both carcinoma subtype and primary site classification. First tier classifier accuracies were 89%, 88%, and 75% for cross-validation, independent, and institutional independent test sets, respectively. Second tier accuracies were 87%, 90%, and 87% for adenocarcinoma, squamous, and neuroendocrine carcinoma respectively. Therefore, we can successfully separate the four main subtypes of carcinoma and subsequently assign primary site by incorporation of gene expression朾ased classifiers into the standard algorithmic pathology approach. PMID:20558571

Centeno, Barbara A.; Bloom, Gregory; Chen, Dung-Tsa; Chen, Zhihua; Gruidl, Mike; Nasir, Aejaz; Yeatman, Timothy Y.

2010-01-01

261

First application close measurements applying the new hybrid integrated MEMS spectrometer  

NASA Astrophysics Data System (ADS)

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.

Gr黦er, Heinrich; P黦ner, Tino; Knobbe, Jens; Schenk, Harald

2013-05-01

262

Monte Carlo Modeling  

NSDL National Science Digital Library

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.

David Joiner

263

Epitaxial growth of semimetallic hybrid substrate systems for low temperature optoelectronic integration of nitrides on silicon  

NASA Astrophysics Data System (ADS)

With increasing device integration and miniaturization, it is desirable to grow Al-Ga-N optoelectronic devices on inexpensive, large size Si wafers. The latter enables seamless integration of optical components with conventional electronics. However, Si has large lattice and thermal expansion mismatches with group-III nitrides, and absorbs visible and UV light emitted by active nitride layers. To circumvent these difficulties, unique hybrid substrates were developed based on HfxZr1-xB2(0001) buffered Si(111) including on-axis and miscut geometries. The work described in this dissertation focuses on epitaxial synthesis, characterization, and theoretical description of strain, thermoelastic behavior, and electronic structure of thick ZrB2 films and associated heterostructures including Si/ZrB2/HfxZr1-xB2, Si/ZrB 2/HfB2 and Si/HfxZr1-xB2. Optical quality ZrB2 films up to 500 nm thick were obtained via reactions of carefully tuned Zr(BH4)/H2 admixtures using gas source molecular beam epitaxy (GS-MBE). A residual tensile strain persisted in these films, independent of thickness, and it vanished at the growth temperature of 900癈. Comparison of the lattice mismatch between sapphire (Al2O3), silicon carbide (SiC), and bulk ZrB 2 substrates with GaN films over 20-900癈 illustrated superior structural and thermal characteristics of the boride templates. Measurements and density functional theory (DFT) simulations of the boride dielectric function and reflectivity indicated metallic Drude behavior across the IR range. At higher energies (2-7 eV) additional spectral features were identified to be interband transitions. The ZrB2 films were used as strain-compensating buffers to fabricate HfxZr1-xB2 including HfB2 . Ellipsometry indicated that the band structure and reflectivity evolved smoothly from ZrB2 to HfB2, paving the way for the fabrication of optimized hybrid substrates, enabling large scale nitride integration with Si technologies via simultaneous optical and strain engineering. The Hf xZr1-xB2/Si technology was utilized to grow Al xGa1-xN via displacement reactions of D2GaN 3 vapors and Al atoms at unprecedented low temperatures (650-700癈), compatible with Si processing. The films exhibited strong cathodoluminescence with narrow peak widths comparable to those observed in MOCVD samples grown at 1100癈. The formation of GaN was investigated theoretically using first principle simulations.

An, Yu Jing

264

Path Integral Monte Carlo Study Confirms a Highly Ordered Snowball in 4He Nanodroplets Doped with an Ar+ Ion  

NASA Astrophysics Data System (ADS)

By means of the exact Path Integral Monte Carlo method we have performed a detailed microscopic study of $^4$He nanodroplets doped with an argon ion, Ar$^+$, at $T=0.5$ K. We have computed density profiles, energies, dissociation energies and characterized the local order around the ion for nanodroplets with a number of 4He atoms ranging from 10 to 64 and also 128. We have found the formation of a stable solid structure around the ion, a "snowball", consisting of 3 concentric shells in which the 4He atoms are placed on at the vertices of platonic solids: the first inner shell is an icosahedron (12 atoms); the second one is a dodecahedron with 20 atoms placed on the faces of the icosahedron of the first shell; the third shell is again an icosahedron composed of 12 atoms placed on the faces of the dodecahedron of the second shell. The "magic numbers" implied by this structure, 12, 32 and 44 helium atoms, have been observed in a recent experimental study [Bartl et al, J. Phys. Chem. A 118, 2014] of these complexes; the dissociation energy curve computed in the present work shows jumps in correspondence with those found in the nanodroplets abundance distribution measured in that experiment, strengthening the agreement between theory and experiment. The same structures were predicted in Ref. [Galli et al, J. Phys. Chem. A 115, 2011] in a study regarding Na$^+$@$^4$He$_n$ when n>30; a comparison between Ar$^+$@$^4$He$_n$ and Na$^+$@$^4$He$_n$ complexes is also presented.

Tramonto, F.; Salvestrini, P.; Nava, M.; Galli, D. E.

2015-01-01

265

Electric-drive tractability indicator integrated in hybrid electric vehicle tachometer  

DOEpatents

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.

Tamai, Goro; Zhou, Jing; Weslati, Feisel

2014-09-02

266

Monte Carlo methods Rmi Bardenet  

E-print Network

Monte Carlo methods R茅mi Bardenet 1 Department of Statistics, Oxford University Abstract. Bayesian inference often requires integrating some function with respect to a posterior distribution. Monte Carlo they are not analytically tractable. We review here the basic principles and the most common Monte Carlo algorithms, among

Boyer, Edmond

267

Advanced Hybrid Spacesuit Concept Featuring Integrated Open Loop and Closed Loop Ventilation Systems  

NASA Technical Reports Server (NTRS)

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.

Daniel, Brian A.; Fitzpatrick, Garret R.; Gohmert, Dustin M.; Ybarra, Rick M.; Dub, Mark O.

2013-01-01

268

Design and realization of 144 x 7 TDI ROIC with hybrid integrated test structure  

NASA Astrophysics Data System (ADS)

Design and realization of a 144x7 silicon readout integrated circuit (ROIC) based on switched capacitor TDI for MCT LWIR scanning type focal plane arrays (FPAs) and its corresponding hybrid integrated test circuits are presented. TDI operation with 7 detectors improves the SNR of the system by a factor of ?7, while oversampling rate of 3 improves the spatial resolution of the system. ROIC supports bidirectional scan, 5 adjustable gain settings, bypass operation, automatic gain adjustment in case of mulfunctioning pixels and pixel select/deselect properties. Integration time of the system can be determined by the help of an external clock. Programming of ROIC can be done in parallel or serial mode according to the needs of the system. All properties except pixel select/deselect property can be performed in parallel mode, while pixel select/deselect property can be performed only in serial mode. ROIC can handle up to 3.75V dynamic range with a load of 25pF and output settling time of 80ns. Input referred noise of the ROIC is less than 750 rms electrons, while the power consumption is less than 100mW. To test ROIC in absence of detector array, a process and temperature compensated current reference array, which supplies uniform input current in range of 1-50nA to ROIC, is designed and measured both in room and cryogenic (77篕) temperatures. Standard deviations of current reference arrays are measured 3.26% for 1nA and 0.99% for 50nA. ROIC and current reference array are fabricated seperately, and then flip-chip bonded for the test of the system. Flip-chip bonded system including ROIC and current reference test array is successfully measured both in room and cryogenic temperatures, and measurement results are presented. The manufacturing technology is 0.35?m, double poly-Si, four metal, 5V CMOS process.

Ceylan, Omer; Kayahan, Huseyin; Yazici, Melik; Baran, Muhammet Burak; Gurbuz, Yasar

2012-06-01

269

Cultivating Curiosity: Integrating Hybrid Teaching in Courses in Human Behavior in the Social Environment  

ERIC Educational Resources Information Center

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

Rodriguez-Keyes, Elizabeth; Schneider, Dana A.

2013-01-01

270

Diffusion-controlled evolution of core-shell nanowire arrays into integrated hybrid nanotube arrays for Li-ion batteries  

NASA Astrophysics Data System (ADS)

Controlled integration of multiple semiconducting oxides into each single unit of ordered nanotube arrays is highly desired in scientific research for the realization of more attractive applications. We herein report a diffusion-controlled solid-solid route to evolve simplex Co(CO3)0.5(OH)0.11H2O@TiO2 core-shell nanowire arrays (NWs) into CoO-CoTiO3 integrated hybrid nanotube arrays (NTs) with preserved morphology. During the evolution procedure, the decomposition of Co(CO3)0.5(OH)0.11H2O NWs into chains of CoCO3 nanoparticles initiates the diffusion process and promotes the interfacial solid-solid diffusion reaction even at a low temperature of 450 癈. The resulting CoO-CoTiO3 NTs possess well-defined sealed tubular geometries and a special ``inner-outer'' hybrid nature, which is suitable for application in Li-ion batteries (LIBs). As a proof-of-concept demonstration of the functions of such hybrid NTs in LIBs, CoO-CoTiO3 NTs are directly tested as LIB anodes, exhibiting both a high capacity (~600 mA h g-1 still remaining after 250 continuous cycles) and a much better cycling performance (no capacity fading within 250 total cycles) than CoO NWs. Our work presents not only a diffusion route for the formation of integrated hybrid NTs but also a new concept that can be employed as a general strategy to fabricate other oxide-based hybrid NTs for energy storage devices.Controlled integration of multiple semiconducting oxides into each single unit of ordered nanotube arrays is highly desired in scientific research for the realization of more attractive applications. We herein report a diffusion-controlled solid-solid route to evolve simplex Co(CO3)0.5(OH)0.11H2O@TiO2 core-shell nanowire arrays (NWs) into CoO-CoTiO3 integrated hybrid nanotube arrays (NTs) with preserved morphology. During the evolution procedure, the decomposition of Co(CO3)0.5(OH)0.11H2O NWs into chains of CoCO3 nanoparticles initiates the diffusion process and promotes the interfacial solid-solid diffusion reaction even at a low temperature of 450 癈. The resulting CoO-CoTiO3 NTs possess well-defined sealed tubular geometries and a special ``inner-outer'' hybrid nature, which is suitable for application in Li-ion batteries (LIBs). As a proof-of-concept demonstration of the functions of such hybrid NTs in LIBs, CoO-CoTiO3 NTs are directly tested as LIB anodes, exhibiting both a high capacity (~600 mA h g-1 still remaining after 250 continuous cycles) and a much better cycling performance (no capacity fading within 250 total cycles) than CoO NWs. Our work presents not only a diffusion route for the formation of integrated hybrid NTs but also a new concept that can be employed as a general strategy to fabricate other oxide-based hybrid NTs for energy storage devices. Electronic supplementary information (ESI) available: SEM images of Co(CO3)0.5(OH)0.11H2O NWs, SEM/TEM images of CoO-CoTiO3 hybrid nanotubes and the calculation of CoTiO3 theoretical capacity. See DOI: 10.1039/c3nr01786a

Jiang, Jian; Luo, Jingshan; Zhu, Jianhui; Huang, Xintang; Liu, Jinping; Yu, Ting

2013-08-01

271

Misalignment tolerant couplers for hybrid integration of semiconductor lasers with silicon photonics parallel transmitters  

NASA Astrophysics Data System (ADS)

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-P閞ot 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.

Romero-Garc韆, S.; Marzban, B.; Sharif Azadeh, S.; Merget, F.; Shen, B.; Witzens, J.

2014-05-01

272

Generalized Darting Monte Carlo Cristian Sminchisescu  

E-print Network

mode structure through local MCMC moves (e.g. diffusion or Hybrid Monte Carlo) but in addition alsoGeneralized Darting Monte Carlo Cristian Sminchisescu Toyota Technological Institute Chicago, USA 92697-3425, USA welling@ics.uci.edu Abstract One of the main shortcomings of Markov chain Monte Carlo

Welling, Max

273

Textile composites with integrated optical fibres: quantification of the influence of single and multiple fibre bends on the light transmission using a Monte Carlo ray-tracing method  

NASA Astrophysics Data System (ADS)

Monte Carlo ray-tracing simulations of the propagation of light rays along bent multimode optical fibres indicate that, for optical fibres integrated into composite components, the influence of macroscale bends induced by the component shape on the light transmission is relatively small. Mesoscale bends caused by integration of the fibres into the reinforcement fabric structure applying textile processes may cause significant transmission losses, which decrease exponentially with increasing ratio of bending radius and fibre radius and increase with increasing bending angles. Based on geometrical models of optical fibres integrated in woven fabric structures, which show multiple mesoscale bends, simulations prove that the lowest bending losses occur for fabrics with a low degree of crimp.

Endruweit, A.; Long, A. C.; Johnson, M. S.

2008-02-01

274

HiRel: Hybrid Automated Reliability Predictor (HARP) integrated reliability tool system, (version 7.0). Volume 2: HARP tutorial  

NASA Technical Reports Server (NTRS)

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.

Rothmann, Elizabeth; Dugan, Joanne Bechta; Trivedi, Kishor S.; Mittal, Nitin; Bavuso, Salvatore J.

1994-01-01

275

Polymer-based Hybrid Integrated Photonic Devices for Silicon On-chip Modulation and Board-level Optical Interconnects  

E-print Network

The accelerating increase in information traffic demands the expansion of optical access network systems that require cost reduction of optical and photonic components. Low cost, ease of fabrication, and integration capabilities of low optical-loss polymers make them attractive for photonic applications. In addition to passive wave-guiding components, electro-optic (EO) polymers consisting of a polymeric matrix doped with organic nonlinear chromophores have enabled wide-RF-bandwidth and low-power optical modulators. Beside board level passive and active optical components, compact on-chip modulators (a few 100 micronmeters to a few millimeters) have been made possible by hybrid integration of EO polymers onto the silicon platform. This paper summarizes some of the recent progress in polymer based optical modulators and interconnects. A highly linear, broadband directional coupler modulator for use in analog optical links and compact, and low-power silicon/polymer hybrid slot photonic crystal waveguide modulat...

Zhang, Xingyu; Lin, Xiaohui; Subbaraman, Harish; Chen, Ray T

2014-01-01

276

Project Integration Office for the electric and hybrid vehicle R and D program. Eighth progress report, March 1982  

SciTech Connect

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)

Not Available

1982-04-19

277

180-degree substrate integrated waveguide hybrid and its application to broadband millimeter-wave single balanced mixer design  

Microsoft Academic Search

This paper presents a broadband millimetre-wave single balanced diode mixer that makes use of an innovative substrate integrated waveguide (SIW) based 180-degree hybrid, fabricated with conventional printed circuit board (PCB) technique. The proposed mixer has advantages over other previously reported millimetre-wave mixer structures judging from a series of aspects such as cost, ease of fabrication, planar construction and broadband performance.

Zhen-Yu Zhang; Ke Wu; Ying Rao Wei

2010-01-01

278

Coupled-slotline-hybrid sampling mixer integrated with step-recovery-diode pulse generator for UWB applications  

Microsoft Academic Search

A new compact low-cost sampling mixer with internal local strobe-pulse generator for (carrierless) ultra-wideband (UWB) applications, especially for sub-sampling of UWB video pulse signals, is presented along with detailed design information. The sampler employs a double-sided planar structure to facilitate interface with the strobe-pulse generator and the baseband circuit without using wire connections or air bridges, enabling hybrid microwave integrated-circuit

Jeongwoo Han; Cam Nguyen

2005-01-01

279

Chromosome localization and gene-copy-number quantification of three random integrations in Chinese-hamster ovary cells and their amplified cell lines using fluorescence in situ hybridization  

Microsoft Academic Search

We have used fluorescence in situ hybridization (FISH) to localize three random Chinese-hamster ovary (CHO) cell chromosomal integration sites and deter- mine gene copy number in their amplified cell lines. Metaphase FISH showed all three to have integrated into different chromosome positions on different chromosomes. All three Geneticin parent cell lines were found to have single integration sites by Southern-

Julian Davies; Mitchell Reff

2001-01-01

280

Monte Carlo analysis of a time-dependent neutron and secondary gamma-ray integral experiment on a thick concrete and steel shield  

NASA Astrophysics Data System (ADS)

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.

Cramer, S. N.; Roussin, R. W.

1981-11-01

281

Monte Carlo Neutrino Oscillations  

E-print Network

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.

James P. Kneller; Gail C. McLaughlin

2005-09-29

282

Hybrid silicon photonic integrated circuits for optical networking E. F. Burmeister, H.-W. Chen, J. P. Mack, Y.-H. Kuo, B. Stameni,  

E-print Network

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

Bowers, John

283

A novel hybrid integrated wind-PV micro co-generation energy scheme for village electricity  

Microsoft Academic Search

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

Adel M. Sharaf; Mohamed A. H. El-Sayed

2009-01-01

284

Integrating Quality Matters into Hybrid Course Design: A Principles of Marketing Case Study  

ERIC Educational Resources Information Center

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

Young, Mark R.

2014-01-01

285

Reexamination of the calculation of two-center, two-electron integrals over Slater-type orbitals. I. Coulomb and hybrid integrals  

NASA Astrophysics Data System (ADS)

In this paper, which constitutes the first part of the series, we consider calculation of two-center Coulomb and hybrid integrals over Slater-type orbitals. General formulas for these integrals are derived with no restrictions on the values of the quantum numbers and nonlinear parameters. Direct integration over the coordinates of one of the electrons leaves us with the set of overlaplike integrals which are evaluated by using two distinct methods. The first one is based on the transformation to the ellipsoidal coordinates system and the second utilizes a recursive scheme for consecutive increase of the angular momenta in the integrand. In both methods simple one-dimensional numerical integrations are used in order to avoid severe digital erosion connected with the straightforward use of the alternative analytical formulas. It is discussed that the numerical integration does not introduce a large computational overhead since the integrands are well-behaved functions, calculated recursively with decent speed. Special attention is paid to the numerical stability of the algorithms. Applicability of the resulting scheme over a large range of the nonlinear parameters is tested on examples of the most difficult integrals appearing in the actual calculations including, at most, 7 i -type functions (l =6 ).

Lesiuk, Micha?; Moszynski, Robert

2014-12-01

286

Integrated compositional and nanomechanical analysis of a polyurethane surface modified with a fluorous oxetane siliceous-network hybrid.  

PubMed

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

Nair, Sithara S; McCullough, Eric J; Yadavalli, Vamsi K; Wynne, Kenneth J

2014-11-01

287

Primordial black hole seeding from hybrid inflation : the direct integration approach  

E-print Network

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 ...

Giguere, Alexis

2013-01-01

288

Hybrid Adeno-Associated Viral Vectors Utilizing Transposase-Mediated Somatic Integration for Stable Transgene Expression in Human Cells  

PubMed Central

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

Zhang, Wenli; Solanki, Manish; M黷her, Nadine; Ebel, Melanie; Wang, Jichang; Sun, Chuanbo; Izsvak, Zsuzsanna; Ehrhardt, Anja

2013-01-01

289

Hybrid adeno-associated viral vectors utilizing transposase-mediated somatic integration for stable transgene expression in human cells.  

PubMed

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

Zhang, Wenli; Solanki, Manish; M黷her, Nadine; Ebel, Melanie; Wang, Jichang; Sun, Chuanbo; Izsvak, Zsuzsanna; Ehrhardt, Anja

2013-01-01

290

Quantum Gibbs ensemble Monte Carlo  

E-print Network

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.

Riccardo Fantoni; Saverio Moroni

2014-08-24

291

Assessment of radiation shield integrity of DD/DT fusion neutron generator facilities by Monte Carlo and experimental methods  

NASA Astrophysics Data System (ADS)

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.

Srinivasan, P.; Priya, S.; Patel, Tarun; Gopalakrishnan, R. K.; Sharma, D. N.

2015-01-01

292

Embodied Energy of Construction Materials: Integrating Human and Capital Energy into an IO-Based Hybrid Model.  

PubMed

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

Dixit, Manish K; Culp, Charles H; Fernandez-Solis, Jose L

2015-02-01

293

ZnSe-based organic杋norganic hybrid structure ultraviolet avalanche photodiodes with long lifetime and its device integration  

NASA Astrophysics Data System (ADS)

We have developed organic [poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)]杋norganic [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.

Inoue, Ryoichi; Abe, Tomoki; Fujimoto, Takeru; Ikadatsu, Noriyuki; Tanaka, Kenta; Uchida, Shigeto; Tazue, Akio; Kasada, Hirofumi; Ando, Koshi; Ichino, Kunio

2015-02-01

294

Wind power integration in hybrid power system with active energy management  

Microsoft Academic Search

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

Abdou Tankari Mahamadou; Bailo Camara Mamadou; Dakyo Brayima; Nichita Cristian

2011-01-01

295

Integrating the Contexts of the Hybrid Basic Course: Using Systems and Social Construction Theory.  

ERIC Educational Resources Information Center

Communication as a discipline is studied in varied contexts: interpersonal, group, organizational, mediated, and public communication. To make clear to students the commonness and not the differences among the contexts, the hybrid basic course should not be taught in separate units as if group communication were a different species from

Dixson, Marcia D.

296

Performance Analysis of Integrated Voice and Data Hybrid-Switched Links  

Microsoft Academic Search

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

GILBERT F. WILLIAMS; A. Leon-Garcia

1984-01-01

297

Employing ethernet spanning tree protocols in an integrated hybrid optical network  

Microsoft Academic Search

Hybrid optical packet\\/circuit switched networking architectures combine the high resource utilization of statistically multiplexed packet switched networks with the circuit switched networks low processing requirements and guaranteed quality of service. Ethernet is emerging as one of the most important standards for the metro and core part of the network. This is motivated by cost-efficiency, and a significant effort from operators

Raimena Veisllari; Steinar Bjornstad

2011-01-01

298

High Efficiency Energy Storage System Design for Hybrid Electric Vehicle with Motor Drive Integration  

Microsoft Academic Search

This paper proposes a new energy storage system (ESS) design including both batteries and ultracapacitors (UC) in hybrid electric vehicle (HEV) and electric vehicle (EV) 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

Shuai Lu; Keith A. Corzine; Mehdi Ferdowsi

2006-01-01

299

Integrated Solid/Nanoporous Copper/Oxide Hybrid Bulk Electrodes for High-performance Lithium-Ion Batteries  

PubMed Central

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

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

300

Integrated solid/nanoporous copper/oxide hybrid bulk electrodes for high-performance lithium-ion batteries.  

PubMed

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

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

301

Large-scale complementary macroelectronics using hybrid integration of carbon nanotubes and IGZO thin-film transistors.  

PubMed

Carbon nanotubes and metal oxide semiconductors have emerged as important materials for p-type and n-type thin-film transistors, respectively; however, realizing sophisticated macroelectronics operating in complementary mode has been challenging due to the difficulty in making n-type carbon nanotube transistors and p-type metal oxide transistors. Here we report a hybrid integration of p-type carbon nanotube and n-type indium-gallium-zinc-oxide thin-film transistors to achieve large-scale (>1,000 transistors for 501-stage ring oscillators) complementary macroelectronic circuits on both rigid and flexible substrates. This approach of hybrid integration allows us to combine the strength of p-type carbon nanotube and n-type indium-gallium-zinc-oxide thin-film transistors, and offers high device yield and low device variation. Based on this approach, we report the successful demonstration of various logic gates (inverter, NAND and NOR gates), ring oscillators (from 51 stages to 501 stages) and dynamic logic circuits (dynamic inverter, NAND and NOR gates). PMID:24923382

Chen, Haitian; Cao, Yu; Zhang, Jialu; Zhou, Chongwu

2014-01-01

302

Fluorescent In Situ Hybridization to Detect Transgene Integration into Plant Genomes  

NASA Astrophysics Data System (ADS)

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.

Schwarzacher, Trude

303

Novel Framework of Integrated Security and Safety System Using Hybrid Network Technology  

Microsoft Academic Search

Advancement in micro-electro mechanical system (MEMS) that integrate mechanical system, sensor, actuator, and electronics has contributed to significant improvement of automation system including security and safety system. This paper will propose a framework of integrated security and safety system that combines microembedded system and computer based system. The framework is designed and developed based on conceptual model of security and

Edi Saputra; K. A. Bakar; H. Herman; S. Hassan

2009-01-01

304

In situ hybridization signal patterns in recurrent laryngeal squamous papillomas indicate that HPV integration occurs at an early stage.  

PubMed

Laryngeal papillomas are benign tumors that frequently recur and can compromise airways. We investigated HPV genotype, physical status, and protein expression in juveniles versus adults. Thirty-five laryngeal papilloma specimens were obtained from ten juveniles (1-16爕ears) and eleven adults (24-67爕ears). In cases of recurrent papillomatosis (7 juveniles, 7 adults), the first and last papillomas were assayed. HPV type was determined by GP5+/6+ PCR and dot blot hybridization. In situ hybridization (ISH) was performed on 34 specimens; the data were recorded in terms of diffuse (episomal HPV) and punctate (integrated HPV) signal patterns. Immunohistochemistry for the HPV L1 capsid protein, a marker of HPV productive status, was performed on 32 samples. All samples tested HPV positive: HPV 11 in 2/10 (20.0%) juveniles and 5/11 (45.5%) adults; HPV 6 in 7/10 (70%) juveniles and 5/11 (45.5%) adults; and HPV 6/11 double infection was noted in one juvenile and one adult. ISH signals (punctate牨燿iffuse) were detected among 7/10 (70.0%) juveniles and 7/11 (63.6%) adults. L1 staining was detected in 1/9 (11.1%) juveniles and 6/10 (60.0%) adults (P=0.06). These data support the idea that integration of low-risk HPV types into the cell genome is an early and common event in the etiology of juvenile and adult recurrent laryngeal papillomas. Productive HPV infections may be more common in adults; accordingly, constant laryngeal re-infection by HPV shed from a productive lesion may contribute to adult recurrent lesions, whereas the mechanism of papilloma recurrence in juveniles may be more attributable to HPV integration. PMID:22052184

Brooks, Erin Grace; Evans, Mark Francis; Adamson, Christine Stewart-Crawford; Peng, Zhihua; Rajendran, Vanitha; Laucirica, Rodolfo; Cooper, Kumarasen

2012-03-01

305

Cost-effective monolithic and hybrid integration for metro and long-haul applications  

NASA Astrophysics Data System (ADS)

Today's telecommunication market is characterized by conservative business practices: tight management of costs, low risk investing and incremental upgrades, rather than the more freewheeling approach taken a few years ago. Optimizing optical components for the current and near term market involves substantial integration, but within particular bounds. The emphasis on evolution, in particular, has led to increased standardization of functions and so created extensive opportunities for integrated product offerings. The same standardization that enables commercially successful integrated functions also changes the competitive environment, and changes the emphasis for component development; shifting the innovation priority from raw performance to delivering the most effective integrated products. This paper will discuss, with specific examples from our transmitter, receiver and passives product families, our understanding of the issues based on extensive experience in delivering high end integrated products to the market, and the direction it drives optical components.

Clayton, Rick; Carter, Andy; Betty, Ian; Simmons, Timothy

2003-12-01

306

On Monte Carlo methods for Bayesian inference  

Microsoft Academic Search

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

Song S. Qian; Craig A. Stow; Mark E. Borsuky

2003-01-01

307

ITS version 5.0 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.  

SciTech Connect

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.

Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

2004-06-01

308

How Safe is Control Banding? Integrated Evaluation by Comparing OELs with Measurement Data and Using Monte Carlo Simulation  

Microsoft Academic Search

The present study aims to explore the protection level that can be achieved by the German con- trol banding (CB) tool Einfaches Massnahmenkonzept Gefahrstoffe, 'Easy-to-use workplace control scheme for hazardous substances'. The rationale of our integrated approach is based on the Bewertungsindex (BWI), which is the quotient of the exposure level and the occupational exposure limit (OEL), with BWI <1

MARTIN TISCHER; SUSANNE BREDENDIEK-KAMPER; ULRICH POPPEK; ROLF PACKROFF

2009-01-01

309

Electronic integration of fuel cell and battery system in novel hybrid vehicle  

NASA Astrophysics Data System (ADS)

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.

Fisher, Peter; Jostins, John; Hilmansen, Stuart; Kendall, Kevin

2012-12-01

310

Integration and evaluation of automated Monte Carlo simulations in the clinical practice of scanned proton and carbon ion beam therapy  

NASA Astrophysics Data System (ADS)

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.

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

311

Integration and evaluation of automated Monte Carlo simulations in the clinical practice of scanned proton and carbon ion beam therapy.  

PubMed

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

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

312

Hybrid glass and sol-gel integrated optical waveguides for absorption-based biosensing  

Microsoft Academic Search

A novel integrated optical planar waveguide platform for absorption-based biosensing is demonstrated. The platform integrates surface ion-exchanged channel waveguides with one-step UV patterned sol-gel structures to define the probing regions. Cytochrome c protein was utilized to characterize the device performance. Spectroscopically specific attenuation of approximately 2 dB in the guided signal occurred at 532nm for 1.4 cm long probing region.

Ismail E. Araci; Nasuhi Yurt; Seppo Honkanen; Sergio B. Mendez; Nasser Peyghambarian

2005-01-01

313

Integrative self-assembly of functional hybrid nanoconstructs by inorganic wrapping of single biomolecules, biomolecule arrays and organic supramolecular assemblies  

NASA Astrophysics Data System (ADS)

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.

Patil, Avinash J.; Li, Mei; Mann, Stephen

2013-07-01

314

Spectral CT Modeling and Reconstruction with Hybrid Detectors in Dynamic-threshold-based Counting and Integrating Modes.  

PubMed

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

Li, Liang; Chen, Zhiqiang; Cong, Wenxiang; Wang, Ge

2014-09-19

315

A hybrid FDTD-Rayleigh integral computational method for the simulation of the ultrasound measurement of proximal femur.  

PubMed

The development of novel quantitative ultrasound (QUS) techniques to measure the hip is critically dependent on the possibility to simulate the ultrasound propagation. One specificity of hip QUS is that ultrasounds propagate through a large thickness of soft tissue, which can be modeled by a homogeneous fluid in a first approach. Finite difference time domain (FDTD) algorithms have been widely used to simulate QUS measurements but they are not adapted to simulate ultrasonic propagation over long distances in homogeneous media. In this paper, an hybrid numerical method is presented to simulate hip QUS measurements. A two-dimensional FDTD simulation in the vicinity of the bone is coupled to the semi-analytic calculation of the Rayleigh integral to compute the wave propagation between the probe and the bone. The method is used to simulate a setup dedicated to the measurement of circumferential guided waves in the cortical compartment of the femoral neck. The proposed approach is validated by comparison with a full FDTD simulation and with an experiment on a bone phantom. For a realistic QUS configuration, the computation time is estimated to be sixty times less with the hybrid method than with a full FDTD approach. PMID:23849752

Cassereau, Didier; Nauleau, Pierre; Bendjoudi, Aniss; Minonzio, Jean-Gabriel; Laugier, Pascal; Bossy, Emmanuel; Grimal, Quentin

2014-07-01

316

Precision measurement of the top quark mass in the lepton + jets channel using a matrix element method with Quasi-Monte Carlo integration  

SciTech Connect

This thesis presents a measurement of the top quark mass obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. The measurement uses a matrix element integration method to calculate a t{bar t} likelihood, employing a Quasi-Monte Carlo integration, which enables us to take into account effects due to finite detector angular resolution and quark mass effects. We calculate a t{bar t} likelihood as a 2-D function of the top pole mass m{sub t} and {Delta}{sub JES}, where {Delta}{sub JES} parameterizes the uncertainty in our knowledge of the jet energy scale; it is a shift applied to all jet energies in units of the jet-dependent systematic error. By introducing {Delta}{sub JES} into the likelihood, we can use the information contained in W boson decays to constrain {Delta}{sub JES} and reduce error due to this uncertainty. We use a neural network discriminant to identify events likely to be background, and apply a cut on the peak value of individual event likelihoods to reduce the effect of badly reconstructed events. This measurement uses a total of 4.3 fb{sup -1} of integrated luminosity, requiring events with a lepton, large E{sub T}, and exactly four high-energy jets in the pseudorapidity range |{eta}| < 2.0, of which at least one must be tagged as coming from a b quark. In total, we observe 738 events before and 630 events after applying the likelihood cut, and measure m{sub t} = 172.6 {+-} 0.9 (stat.) {+-} 0.7 (JES) {+-} 1.1 (syst.) GeV/c{sup 2}, or m{sub t} = 172.6 {+-} 1.6 (tot.) GeV/c{sup 2}.

Lujan, Paul Joseph; /UC, Berkeley /LBL, Berkeley

2009-12-01

317

Sequential Monte Carlo Methods to Train Neural Network Models  

Microsoft Academic Search

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

Jo鉶 F. G. De Freitas; Mahesan Niranjan; Andrew H. Gee; Arnaud Doucet

2000-01-01

318

Hypervolume Monte Carlo Model  

NSDL National Science Digital Library

The Hypervolume Monte Carlo Model implements microcanonical simulations by sampling the position and momentum spaces. Although it is strictly proven in the thermodynamic limit, HVMC works well with a relatively small number of molecules. In contrast to other algorithms for Monte Carlo simulations, HVMC does not involve previous integration over the momentum space or demons. It is the full non-deterministic counter part of the NVE molecular dynamics method, also providing speed distribution functions. Moreover, the method allows a straightforward simulation of the ideal gas. The Hypervolume Monte Carlo Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Fernandes, Fernando S.

2012-12-04

319

Preliminary study of two-dimensional SU(N) Yang-Mills theory with adjoint matter by Hybrid Monte Carlo approach  

E-print Network

Two-dimensional non-abelian quantum field models provide a useful laboratory for analytic and numerical investigations of quantum theories with gauge symmetry. They can exhibit various features, such as charge confinement, which are known from D=4 theories like QCD. Several analytic predictions concerning the spectra of two-dimensional systems with adjoint matter were postulated and numerical results were obtained using Discrete Light Cone Quantization techniques, however none of them has been checked via Monte Carlo simulations. In this Letter we present two such models which are particularly interesting from the physical point of view and discuss first numerical results.

Piotr Korcyl; Mateusz Koren

2011-11-20

320

Integration of Ecogpt and SV40 early region sequences into human chromosome 17: a dominant selection system in whole cell and microcell human-mouse hybrids.  

PubMed Central

The dominant selectable gene, Ecogpt, has been introduced, by the calcium phosphate precipitation technique, into normal human fibroblasts, along with the SV40 early region genes. In one transfectant clone, integration of these sequences into human chromosome 17 was demonstrated by the construction of human-mouse somatic cell hybrids, selected for by growth in medium containing mycophenolic acid and xanthine. A whole cell hybrid, made between the human transfectant and a mouse L cell, was used as donor of the Ecogpt-carrying human chromosome 17 to 'tribrids' growing in suspension, made by whole cell fusion between a mouse thymoma cell line, and to microcell hybrids made with a mouse teratocarcinoma cell line. Two tribrids contained karyotypically normal human chromosomes 17 and a small number of other human chromosomes, while a third tribrid had a portion of the long arm of chromosome 17 translocated to mouse as its only human genetic material. Two independent microcell hybrids contained a normal chromosome 17 and no other human chromosome on a mouse teratocarcinoma background. These experiments demonstrate the ability to construct human-mouse somatic cell hybrids using a dominant selection system. By applying this approach it should be possible to select for a wide range of different human chromosomes in whole cell and microcell hybrids. In particular, transfer of single human chromosomes to mouse teratocarcinoma cells will allow examination of developmentally regulated human gene sequences after differentiation of such hybrids. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:11892815

Tunnacliffe, A; Parkar, M; Povey, S; Bengtsson, B O; Stanley, K; Solomon, E; Goodfellow, P

1983-01-01

321

A hybrid approach for integrated healthcare cooperative purchasing and supply chain configuration.  

PubMed

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

Rego, Nazar; Claro, Jo鉶; Pinho de Sousa, Jorge

2014-12-01

322

Design of a Hybrid Integrated EMC Filter for a DC朌C Power Converter  

Microsoft Academic Search

This study focuses on the design and the realization of an integrated EMI filter embedded in an aircraft power supply. The first part of the study is dedicated to the modeling of the dc杁c power, based on a 揵lack box representation: the converter is represented by an association of sources and impedances that reflect its external EMI behavior. This initial

Marwan Ali; Eric Labour; Fran鏾is Costa; Bertrand Revol

2012-01-01

323

Software design for sequential\\/hybrid time integration in the Community Climate System Model  

Microsoft Academic Search

All current releases of the Community Climate System Model (CCSM) have employed a concurrent integration scheme where the four main components, the atmosphere, ocean, land and sea ice models, are scheduled to execute concurrently on separate sets of processors. Although in theory this can make more efficient use of large numbers of processors, in practice data serialization between the models

R. Jacob; M. Vertenstein; T. Craig; J. Dennis; B. Kauffman

2007-01-01

324

Development of an Integrated GIS and Land Use Planning Course: Impacts of Hybrid Instructional Methods  

ERIC Educational Resources Information Center

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

Kamruzzaman, M.

2014-01-01

325

Cost-effective monolithic and hybrid integration for metro and long-haul applications  

Microsoft Academic Search

Today's telecommunication market is characterized by conservative business practices: tight management of costs, low risk investing and incremental upgrades, rather than the more freewheeling approach taken a few years ago. Optimizing optical components for the current and near term market involves substantial integration, but within particular bounds. The emphasis on evolution, in particular, has led to increased standardization of functions

Rick Clayton; Andy Carter; Ian Betty; Timothy Simmons

2003-01-01

326

An Improved Monte Carlo Algorithm for Elastic Electron Backscattering  

E-print Network

An Improved Monte Carlo Algorithm for Elastic Electron Backscattering from Surfaces Ivan T. Dimov of electrons satisfies an integral equation, which might be solved by Monte Carlo methods. The Monte Carlo ap process. We introduce different weights in the Monte Carlo algorithm, which de- crease the variance. We

Dimov, Ivan

327

Hybrid integration of InP photodetectors with SOI waveguides using thermocompression bonding  

NASA Astrophysics Data System (ADS)

In this paper we present the integration of an InP-based photodetector with silicon-on-insulator (SOI) waveguides using thermocompression bonding. A BCB prism integrated on top of the light-sensitive area of a planar detector (PD) chip deflects the light from a 4 ?m thick SOI waveguide upward into the flip-chip bonded PD. A trench is etched in front of the SOI waveguide to accommodate prisms with apexes up to 7 ?m. Using thermocompression bonding between thin gold pads (~500 nm thickness) deposited on both, SOI and photodetector chips an excellent vertical alignment accuracy of +/-100 nm can be achieved, limited only by etching and Au-deposition tolerances. A commercial flip-chip bonder provides a lateral alignment accuracy also in the sub-micron range. Together with a previously developed process for integrating lasers and SOA chips using the same technology, fully functional PICs can now be realized on the SOI platform using thermocompression bonding.

Harjanne, Mikko; Kapulainen, Markku; Ylinen, Sami; Aalto, Timo; Ollila, Jyrki; M鰎l, Ludwig; Passenberg, Wolfgang

2010-05-01

328

Monte Carlo sampling from the quantum state space. II  

E-print Network

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.

Yi-Lin Seah; Jiangwei Shang; Hui Khoon Ng; David John Nott; Berthold-Georg Englert

2014-10-02

329

Integrated thermal and energy management of plug-in hybrid electric vehicles  

NASA Astrophysics Data System (ADS)

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.

Shams-Zahraei, Mojtaba; Kouzani, Abbas Z.; Kutter, Steffen; B鋕er, Bernard

2012-10-01

330

Air purification from TCE and PCE contamination in a hybrid bioreactors and biofilter integrated system.  

PubMed

A two-stage waste air treatment system, consisting of hybrid bioreactors (modified bioscrubbers) and a biofilter, was used to treat waste air containing chlorinated ethenes - trichloroethylene (TCE) and tetrachloroethylene (PCE). The bioreactor was operated with loadings in the range 0.46-5.50gm(-3)h(-1) for TCE and 2.16-9.02gm(-3)h(-1) for PCE. The biofilter loadings were in the range 0.1-0.97gm(-3)h(-1) for TCE and 0.2-2.12gm(-3)h(-1) for PCE. Under low pollutant loadings, the efficiency of TCE elimination was 23-25% in the bioreactor and 54-70% in the biofilter. The efficiency of PCE elimination was 44-60% in the bioreactor and 50-75% in the biofilter. The best results for the bioreactor were observed one week after the pollutant loading was increased. However, the process did not stabilize. In the next seven days contaminant removal efficiency, enzymatic activity and biomass content were all diminished. PMID:24316808

Tabernacka, Agnieszka; Zborowska, Ewa; Lebkowska, Maria; Borawski, Maciej

2014-01-15

331

Improving dynamical lattice QCD simulations through integrator tuning using Poisson brackets and a force-gradient integrator  

SciTech Connect

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.

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

332

Hybrid information privacy system: integration of chaotic neural network and RSA coding  

NASA Astrophysics Data System (ADS)

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.

Hsu, Ming-Kai; Willey, Jeff; Lee, Ting N.; Szu, Harold H.

2005-03-01

333

A hybrid source apportionment model integrating measured data and air quality model results  

NASA Astrophysics Data System (ADS)

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 Carb髇 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 40% to 30%, while Mexico's contribution increased from 24-32% to 40%. The contribution from the Carb髇 facility increased from 14% to over 20%. Contributions from Texas and the western United States changed little, with final contributions of 16% and 5-9%, respectively. The increase in Mexico's contribution is consistent with more recent SO2 emissions estimates that indicate that the BRAVO Mexican SO2 emissions were underestimated. Source attribution results for other monitoring sites in west Texas were similar to results at Big Bend. In eastern Texas, the eastern United States accounted for up to 70% of the measured sulfate, with Texas contributing 20-30%.

Schichtel, Bret A.; Malm, William C.; Gebhart, Kristi A.; Barna, Michael G.; Knipping, Eladio M.

2006-04-01

334

High quality proton beams from hybrid integrated laser-driven ion acceleration systems  

NASA Astrophysics Data System (ADS)

We consider a hybrid acceleration scheme for protons where the laser generated beam is selected in energy and angle and injected into a compact linac, which raises the energy from 30 to 60 MeV. The laser acceleration regime is TNSA and the energy spectrum is determined by the cutoff energy and proton temperature. The dependence of the spectrum on the target properties and the incidence angle is investigated with 2D PIC simulations. We base our work on widely available technologies and on laser with a short pulse, having in mind a facility whose cost is approximately 15 M. Using a recent experiment as the reference, we choose the laser pulse and target so that the energy spectrum obtained from the 3D PIC simulation is close to the one observed, whose cutoff energy was estimated to be over 50 MeV. Laser accelerated protons in the TNSA regime have wide energy spectrum and broad divergence. In this paper we compare three transport lines, designed to perform energy selection and beam collimation. They are based on a solenoid, a quadruplet of permanent magnetic quadrupoles and a chicane. To increase the maximum available energy, which is actually seen as an upper limit due to laser properties and available targets, we propose to inject protons into a small linac for post-acceleration. The number of selected and injected protons is the highest with the solenoid and lower by one and two orders of magnitude with the quadrupoles and the chicane respectively. Even though only the solenoid enables achieving to reach a final intensity at the threshold required for therapy with the highest beam quality, the other systems will be very likely used in the first experiments. Realistic start-to-end simulations, as the ones reported here, are relevant for the design of such experiments.

Sinigardi, Stefano; Turchetti, Giorgio; Rossi, Francesco; Londrillo, Pasquale; Giove, Dario; De Martinis, Carlo; Bolton, Paul R.

2014-03-01

335

Investigation of the effects of laser non-linearity and RIN in direct modulation hybrid wired/wireless PON systems employing an integrated two section laser  

NASA Astrophysics Data System (ADS)

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.

Saljoghei, Arsalan; Browning, Colm; Smyth, Frank; Barry, Liam P.

2015-03-01

336

Quantum Gibbs ensemble Monte Carlo.  

PubMed

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. PMID:25240348

Fantoni, Riccardo; Moroni, Saverio

2014-09-21

337

Optimally Combining Sampling Techniques for Monte Carlo Rendering  

E-print Network

Optimally Combining Sampling Techniques for Monte Carlo Rendering Eric Veach Leonidas J. Guibas Computer Science Department Stanford University Abstract Monte Carlo integration is a powerful technique for the evaluation of difficult integrals. Applications in rendering include distribution ray tracing, Monte Carlo

Stanford University

338

Integrated design and analysis of smart actuators for hybrid assistive knee bracese-fla  

NASA Astrophysics Data System (ADS)

The objective of this paper is to develop smart actuators for knee braces as assistive devices for helping disabled people to recover their mobility. The actuator functions as motor, clutch, and brake. In the design, magnetorheological (MR) fluids are utilized to generate controllable torque. To decrease the size of the actuator, motor and MR fluids are integrated. MR fluids are filled inside the DC motor based actuator. Additional design factors of smart actuators including influence of permanent magnet on MR fluids and dynamic sealing are also considered. Finite element model of the smart actuator is built and analyzed. A prototype of the smart actuator with two different inner armatures is fabricated and their characteristics are investigated. Torques are compared between simulation and experiments. The results show that the developed smart actuator with multiple functions is promising for assistive knee braces.

Guo, H. T.; Liao, W. H.

2009-03-01

339

APPLICATIONS OF LASERS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Hybrid coupling in integrated injection laser arrays  

NASA Astrophysics Data System (ADS)

Analytic and numerical investigations are reported of the mode composition of the radiation emitted by integrated injection laser arrays consisting of an arbitrary number of components coupled by Y junctions and by a slight overlap of the fields of parallel parts of waveguides. An analysis of symmetric Y couplers is made also near the lasing threshold. A strong dependence of the mode composition of the output radiation on the weak coupling between the parallel waveguides and/or on the waveguide length is revealed. An allowance for weak coupling in Y-coupler arrays alters considerably the distribution of the radiation intensity of the first array mode in the far-field zone and the changes are manifested mainly by a relative increase of the side lobes of the angular distribution of the output radiation.

Mikhal'kov, A. Yu; Plyavenek, Andrei G.

1991-02-01

340

Propulsion Airframe Aeroacoustic Integration Effects for a Hybrid Wing Body Aircraft Configuration  

NASA Technical Reports Server (NTRS)

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.

Czech, Michael J.; Thomas, Russell H.; Elkoby, Ronen

2010-01-01

341

Integrating Remote Sensing Data, Hybrid-Cloud Computing, and Event Notifications for Advanced Rapid Imaging & Analysis (Invited)  

NASA Astrophysics Data System (ADS)

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.

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

342

A hybrid optical switch architecture to integrate IP into optical networks to provide flexible and intelligent bandwidth on demand for cloud computing  

NASA Astrophysics Data System (ADS)

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.

Yang, Wei; Hall, Trevor J.

2013-12-01

343

Nanoscale integration of SiC/SiO2 core-shell nanocables in diamond through a simultaneous hybrid structure fabrication  

NASA Astrophysics Data System (ADS)

The nanoscale integration of SiC nanocables in a diamond thin film is achieved through a novel synthetic pathway, which combines Fe catalyst and detonation nanodiamond seeding technique in a microwave plasma chemical vapor deposition process. The obtained hybrid structures show controllable SiC nanocable fraction depending on the relative fraction of iron catalyst and diamond seeds. The SiC nanocable has a conical structure with 10 nm diameter SiC core, surrounded by SiO2 shell. The diamond crystals show high quality/crystallinity even for hybrid structures featuring an increasing SiC nanocable fraction. In the end, the growth behavior of the hybrid structure is discussed.

Zhuang, Hao; Zhang, Lei; Staedler, Thorsten; Jiang, Xin

2012-05-01

344

Integrated Plasma Simulation of Lower Hybrid Current Drive Modification of Sawtooth in Alcator C-Mod  

NASA Astrophysics Data System (ADS)

Experiments were performed in Alcator C-Mod, where the onset time for sawteeth was delayed significantly (up to 0.5 s) relative to ohmically heated plasmas, through injection of off-axis LH current drive power [1]. In this poster we discuss simulations of these experiments using the Integrated Plasma Simulator (IPS) [2], through which driven current density profiles and hard x-ray spectra are computed using a ray tracing code (GENRAY) and Fokker Planck code (CQL3D) [3], that are executed repeatedly in time. The background plasma is evolved in these simulations using the TSC transport code with the Porcelli sawtooth model [4]. [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. Mtg. on Sim. and Mod. of Therm. Plasmas, Montreal, Canada (1992). [0pt] [4] S. C. Jardin et al, Journal Comp. Phys. 66, 481 (1986).

Bonoli, P. T.; Hubbard, A. E.; Schmidt, A. E.; Wright, J. C.; Kessel, C. E.; Batchelor, D. B.; Berry, L. A.; Harvey, R. W.

2010-11-01

345

Integrated Plasma Simulation of Lower Hybrid Current Drive Modification of Sawtooth  

NASA Astrophysics Data System (ADS)

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], through which driven current density profiles are computed using a ray tracing code (GENRAY) and Fokker Planck code (CQL3D) [3]. These modules are executed repeatedly as 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. [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).

Bonoli, P. T.; Wright, J. C.; Kessel, C. E.; Batchelor, D. B.; Berry, L. A.; Harvey, R. W.

2011-11-01

346

A compact frequency-domain photon migration system for integration into commercial hybrid small animal imaging scanners for fluorescence tomography  

PubMed Central

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

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

347

Real-time hybrid simulation of a complex bridge model with MR dampers using the convolution integral method  

NASA Astrophysics Data System (ADS)

Magneto-rheological (MR) fluid dampers can be used to reduce the traffic induced vibration in highway bridges and protect critical structural components from fatigue. Experimental verification is needed to verify the applicability of the MR dampers for this purpose. Real-time hybrid simulation (RTHS), where the MR dampers are physically tested and dynamically linked to a numerical model of the highway bridge and truck traffic, provides an efficient and effective means to experimentally examine the efficacy of MR dampers for fatigue protection of highway bridges. In this paper a complex highway bridge model with 263?178 degrees-of-freedom under truck loading is tested using the proposed convolution integral (CI) method of RTHS for a semiactive structural control strategy employing two large-scale 200 kN MR dampers. The formation of RTHS using the CI method is first presented, followed by details of the various components in the RTHS and a description of the implementation of the CI method for this particular test. The experimental results confirm the practicability of the CI method for conducting RTHS of complex systems.

Jiang, Zhaoshuo; Jig Kim, Sung; Plude, Shelley; Christenson, Richard

2013-10-01

348

A compact frequency-domain photon migration system for integration into commercial hybrid small animal imaging scanners for fluorescence tomography  

NASA Astrophysics Data System (ADS)

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 礛 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.

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

349

Detection of Pulmonary Nodules in CT Images Based on Fuzzy Integrated Active Contour Model and Hybrid Parametric Mixture Model  

PubMed Central

The segmentation and detection of various types of nodules in a Computer-aided detection (CAD) system present various challenges, especially when (1) the nodule is connected to a vessel and they have very similar intensities; (2) the nodule with ground-glass opacity (GGO) characteristic possesses typical weak edges and intensity inhomogeneity, and hence it is difficult to define the boundaries. Traditional segmentation methods may cause problems of boundary leakage and 搘eak local minima. This paper deals with the above mentioned problems. An improved detection method which combines a fuzzy integrated active contour model (FIACM)-based segmentation method, a segmentation refinement method based on Parametric Mixture Model (PMM) of juxta-vascular nodules, and a knowledge-based C-SVM (Cost-sensitive Support Vector Machines) classifier, is proposed for detecting various types of pulmonary nodules in computerized tomography (CT) images. Our approach has several novel aspects: (1) In the proposed FIACM model, edge and local region information is incorporated. The fuzzy energy is used as the motivation power for the evolution of the active contour. (2) A hybrid PMM Model of juxta-vascular nodules combining appearance and geometric information is constructed for segmentation refinement of juxta-vascular nodules. Experimental results of detection for pulmonary nodules show desirable performances of the proposed method. PMID:23690876

Li, Bin; Chen, Kan; Tian, Lianfang; Yeboah, Yao; Ou, Shanxing

2013-01-01

350

Evaporation-Induced Self-Assembly of Hybrid Bridged Silsesquioxane Film and Particulate Mesophases with Integral Organic Functionality  

SciTech Connect

Since the discovery of surfactant-templated silica mesophases, the development of organic modification schemes to impart functionality to the pore surfaces has received much attention. Most recently, using the general class of compounds referred to as bridged silsesquioxanes (RO){sub 3}Si-R{prime}-Si(OR){sub 3} (Scheme 1), three research groups have reported the formation of a new class of poly(bridgedsilsesquioxane) mesophases BSQMs with integral organic functionality. In contrast to previous hybrid mesophases where organic ligands or molecules are situated on pore surfaces, this class of materials necessarily incorporates the organic constituents into the framework as molecularly dispersed bridging ligands. Although it is anticipated that this new mesostructural organization should result in synergistic properties derived from the molecular scale mixing of the inorganic and organic components, few properties of BSQMs have been measured. In addition samples prepared to date have been in the form of granular precipitates, precluding their use in applications like membranes, fluidics, and low k dielectric films needed for all foreseeable future generations of microelectronics.

LU,YUNFENG; FAN,HONGYOU; DOKE,NILESH; LOY,DOUGLAS A.; ASSINK,ROGER A.; LAVAN,DAVID A.; BRINKER,C. JEFFREY

2000-06-12

351

Using a hybrid Monte Carlo/ Slip Estimator-Genetic Algorithm (MCSE-GA) to produce high resolution estimates of paleoearthquakes from geodetic data  

NASA Astrophysics Data System (ADS)

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.

Lindsay, Anthony; McCloskey, John; Sim鉶, Nuno; Murphy, Shane; Bhloscaidh, Mairead Nic

2014-05-01

352

Low threshold vertical cavity surface emitting lasers integrated onto Si-CMOS ICs using novel hybrid assembly techniques  

E-print Network

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 ...

Perkins, James Michael, 1978-

2007-01-01

353

A Multi-Level Grid Interactive Bi-directional AC/DC-DC/AC Converter and a Hybrid Battery/Ultra-capacitor Energy Storage System with Integrated Magnetics for Plug-in Hybrid Electric Vehicles  

SciTech Connect

This study presents a bi-directional multi-level power electronic interface for the grid interactions of plug-in hybrid electric vehicles (PHEVs) as well as a novel bi-directional power electronic converter for the combined operation of battery/ultracapacitor hybrid energy storage systems (ESS). The grid interface converter enables beneficial vehicle-to-grid (V2G) interactions in a high power quality and grid friendly manner; i.e, the grid interface converter ensures that all power delivered to/from grid has unity power factor and almost zero current harmonics. The power electronic converter that provides the combined operation of battery/ultra-capacitor system reduces the size and cost of the conventional ESS hybridization topologies while reducing the stress on the battery, prolonging the battery lifetime, and increasing the overall vehicle performance and efficiency. The combination of hybrid ESS is provided through an integrated magnetic structure that reduces the size and cost of the inductors of the ESS converters. Simulation and experimental results are included as prove of the concept presenting the different operation modes of the proposed converters.

Onar, Omer C [ORNL] [ORNL

2011-01-01

354

Integrated, Feed-Forward Hybrid Electric Vehicle Simulation in SIMULINK and its Use for Power Management Studies  

Microsoft Academic Search

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

Chan-Chiao Lin; Zoran Filipi; Yongsheng Wang; Loucas Louca; Huei Peng; Dennis Assanis; Jeffrey Stein

2001-01-01

355

Analysis of 3D fluid driven crack propagation problem in co-seismic slip under P- and S-waves by hybrid hypersingular integral method  

Microsoft Academic Search

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

B. J. Zhu; Y. L. Shi; M. C. Sukop; Y. B. Li; T. Y. Qin

2009-01-01

356

A 60 GHz MMIC pHEMT image reject mixer with integrated ultra wideband IF hybrid and 30 dB of image rejection ratio  

Microsoft Academic Search

A 60 GHz image reject mixer (IRM) with an integrated ultra wideband IF hybrid has been designed, fabricated and characterized in a commercial pHEMT MMIC process. A measured conversion loss (Lc) of 10.2 to 11.4 dB over the frequency range 55 to 65 GHz is obtained with a state-of-the-art image rejection ratio (IRR) of 30 dB at the 60 GHz

Sten E. Gunnarsson; Dan Kuylenstierna; Herbert Zirath

2005-01-01

357

Monte Carlo methods Sequential Monte Carlo  

E-print Network

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

Doucet, Arnaud

358

A critical evaluation of secondary cancer risk models applied to Monte Carlo dose distributions of 2-dimensional, 3-dimensional conformal and hybrid intensity-modulated radiation therapy for breast cancer  

NASA Astrophysics Data System (ADS)

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.

2014-08-01

359

Error in Monte Carlo, quasi-error in Quasi-Monte Carlo  

E-print Network

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.

R. H. Kleiss; A. Lazopoulos

2005-04-12

360

A new algorithm for accurate and fast numerical evaluation of hybrid and three-centre two-electron Coulomb integrals over Slater-type functions  

NASA Astrophysics Data System (ADS)

Recently we developed a new algorithm for a fast and accurate numerical evaluation of three-centre nuclear attraction integrals over Slater-type functions, the results obtained were very satisfactory. Now, it is shown that this new algorithm can also be applied to hybrid and three-centre two-electron Coulomb integrals over Slater-type functions. These integrals, which are numerous, are very difficult to evaluate to a high accuracy, because of the presence of spherical Bessel functions and hypergeometric series in the integrands. We have proved that the integrands that occur in the analytic expressions of the integrals under consideration satisfy all the conditions to apply the S\\skew2\\bar{D} approach. The hypergeometric functions which occur in the semi-infinite integrals can be expressed as a finite expansion and the semi-infinite integrals involving the spherical Bessel functions can be transformed into semi-infinite integrals involving the simple sine function. The numerical results obtained with linear and non-linear systems illustrate clearly a further improvement of accuracy and a substantial reduction in calculation times. Comparisons with existing codes, STOP developed by Bouferguene et al (1996 Int. J. Quantum Chem. 57 801) and ADGGSTNGINT developed by Rico et al (1997 Comp. Phys. Commun. 105 216), are listed.

Berlu, Lilian; Safouhi, Hassan

2003-11-01

361

Desiccant-Based Combined Systems: Integrated Active Desiccant Rooftop Hybrid System Development and Testing Final Report- Phase 4  

SciTech Connect

This report summarizes the results of a research and development (R&D) program to design and optimize an active desiccant-vapor compression hybrid rooftop system. The primary objective was to combine the strengths of both technologies to produce a compact, high-performing, energy-efficient system that could accommodate any percentage of outdoor air and deliver essentially any required combination of temperature and humidity, or sensible heat ratio (SHR). In doing so, such a product would address the significant challenges imposed on the performance capabilities of conventional packaged rooftop equipment by standards 62 and 90.1 of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. The body of work completed as part of this program built upon previous R&D efforts supported by the U.S. Department of Energy and summarized by the Phase 3b report ''Active Desiccant Dehumidification Module Integration with Rooftop Packaged HVAC Units'' (Fischer and Sand 2002), in addition to Fischer, Hallstrom, and Sand 2000; Fischer 2000; and Fischer and Sand 2004. All initial design objectives established for this development program were successfully achieved. The performance flexibility desired was accomplished by a down-sized active desiccant wheel that processes only a portion of the supply airflow, which is pre-conditioned by a novel vapor compression cycle. Variable-speed compressors are used to deliver the capacity control required by a system handling a high percentage of outdoor air. An integrated direct digital control system allows for control capabilities not generally offered by conventional packaged rooftop systems. A 3000-cfm prototype system was constructed and tested in the SEMCO engineering test laboratory in Columbia, MO, and was found to operate in an energy-efficient fashion relative to more conventional systems. Most important, the system offered the capability to independently control the supply air temperature and humidity content to provide individual sensible and latent loads required by an occupied space without over-cooling and reheating air. The product was developed using a housing construction similar to that of a conventional packaged rooftop unit. The resulting integrated active desiccant rooftop (IADR) is similar in size to a currently available conventional rooftop unit sized to provide an equivalent total cooling capacity. Unlike a conventional rooftop unit, the IADR can be operated as a dedicated outdoor air system processing 100% outdoor air, as well as a total conditioning system capable of handling any ratio of return air to outdoor air. As part of this R&D program, a detailed investigation compared the first cost and operating cost of the IADR with costs for a conventional packaged approach for an office building located in Jefferson City, MO. The results of this comparison suggest that the IADR approach, once commercialized, could be cost-competitive with existing technology--exhibiting a one-year to two-year payback period--while simultaneously offering improved humidity control, indoor air quality, and energy efficiency.

Fischer, J

2005-05-06

362

Analytical Applications of Monte Carlo Techniques.  

ERIC Educational Resources Information Center

Described are analytical applications of the theory of random processes, in particular solutions obtained by using statistical procedures known as Monte Carlo techniques. Supercomputer simulations, sampling, integration, ensemble, annealing, and explicit simulation are discussed. (CW)

Guell, Oscar A.; Holcombe, James A.

1990-01-01

363

Dual-facet coupling of SOA array on 4-?m silicon-on-insulator implementing a hybrid integrated SOA-MZI wavelength converter  

NASA Astrophysics Data System (ADS)

Hybrid integration on Silicon-on-Insulator (SOI) has emerged as a practical solution for compact and high-performance Photonic Integrated Circuits (PICs). It aims at combining the cost-effectiveness and CMOS-compatibility benefits of the low-loss SOI waveguide platform with the versatile active optical functions that can be realized by III-V photonic materials. The utilization of SOI, as an integration board, with ?m-scale dimensions allows for an excellent optical mode matching between silicon rib waveguides and active chips, allowing for minimal-loss coupling of the pre-fabricated IIIV components. While dual-facet coupling as well as III-V multi-element array bonding should be employed to enable enhanced active on-chip functions, so far only single side SOA bonding has been reported. In the present communication, we present a novel integration scheme that flip-chip bonds a 6-SOA array on 4-?m thick SOI technology by coupling both lateral SOA facets to the waveguides, and report on the experimental results of wavelength conversion operation of a dual-element Semiconductor Optical Amplifier - Mach Zehnder Interferometer (SOA-MZI) circuit. Thermocompression bonding was applied to integrate the pre-fabricated SOAs on SOI, with vertical and horizontal alignment performed successfully at both SOA facets. The demonstrated device has a footprint of 8.2mm x 0.3mm and experimental evaluation revealed a 12Gb/s wavelength conversion operation capability with only 0.8dB power penalty for the first SOA-MZI-on-SOI circuit and a 10Gb/s wavelength conversion operation capability with 2 dB power penalty for the second SOA-MZI circuit. Our experiments show how dual facet integration can significantly increase the level of optical functionalities achievable by flip-chip hybrid technology and pave the way for more advanced and more densely PICs.

Alexoudi, T.; Fitsios, D.; Kanellos, G. T.; Pleros, N.; Tekin, T.; Cherchi, M.; Ylinen, S.; Harjanne, M.; Kapulainen, M.; Aalto, T.

2014-03-01

364

Optimal Design via Curve Fitting of Monte Carlo Experiments  

E-print Network

Optimal Design via Curve Fitting of Monte Carlo Experiments Peter M篓 uller and Giovanni Parmigiani : : : : : : : : : : : 15 4.3.3 Curve fitting of Monte Carlo experiments : : : : : : : : 16 5 CONSISTENCY AND UNCERTAINTY 18 approximation. : : : : : : : : : : : : : : : 14 4.3.2 Large scale Monte Carlo integration

West, Mike

365

Bayesian Monte Carlo Carl Edward Rasmussen and Zoubin Ghahramani  

E-print Network

Bayesian Monte Carlo Carl Edward Rasmussen and Zoubin Ghahramani Gatsby Computational Neuroscience,zoubin@gatsby.ucl.ac.uk http://www.gatsby.ucl.ac.uk Abstract We investigate Bayesian alternatives to classical Monte Carlo methods for evaluating integrals. Bayesian Monte Carlo (BMC) allows the in- corporation of prior knowledge

Ghahramani, Zoubin

366

Evidence that the proliferation stage of micropropagation procedure is determinant in the expression of banana streak virus integrated into the genome of the FHIA 21 hybrid (Musa AAAB).  

PubMed

Banana streak virus (BSV) is causing increasing concern in almost every producing area of banana and plantain (Musa spp.) worldwide. This situation appeared partially linked to some breeding lines and micropropagated hybrids. A complete BSV sequence integrated into the genome of a triploid plantain has been recently characterised and it has been hypothesised that it could give rise to infectious virus via recombination. In this study, we evaluated the effect of a routine micropropagation procedure on the expression of BSV in the FHIA 21 tetraploid hybrid. The widespread presence of integrated sequences and the absence of episomal BSV in thirty FHIA 21 "mother plants" selected for micropropagation were first confirmed by specific PCR and IC-PCR tests. The proliferation stage of the procedure, characterised by an intensive production of neoformed buds, appeared determinant in BSV expression whereas the rooting and acclimatisation stages had little or no effect. The duration in culture and the way of subdividing the clumps of proliferation influenced greatly the percentage of episomal BSV infections, reaching 58% of infected micropropagated lines after six in vitro subcultures. These data suggest that the expression of episomal BSV observed during the in vitro procedure is correlated with the presence of an integrated form. PMID:11765919

Dallot, S; Acu馻, P; Rivera, C; Ram韗ez, P; C魌e, F; Lockhart, B E; Caruana, M L

2001-01-01

367

Modelling personal exposure to particulate air pollution: An assessment of time-integrated activity modelling, Monte Carlo simulation & artificial neural network approaches.  

PubMed

An experimental assessment of personal exposure to PM10 in 59 office workers was carried out in Dublin, Ireland. 255 samples of 24-h personal exposure were collected in real time over a 28 month period. A series of modelling techniques were subsequently assessed for their ability to predict 24-h personal exposure to PM10. Artificial neural network modelling, Monte Carlo simulation and time-activity based models were developed and compared. The results of the investigation showed that using the Monte Carlo technique to randomly select concentrations from statistical distributions of exposure concentrations in typical microenvironments encountered by office workers produced the most accurate results, based on 3 statistical measures of model performance. The Monte Carlo simulation technique was also shown to have the greatest potential utility over the other techniques, in terms of predicting personal exposure without the need for further monitoring data. Over the 28 month period only a very weak correlation was found between background air quality and personal exposure measurements, highlighting the need for accurate models of personal exposure in epidemiological studies. PMID:25260856

McCreddin, A; Alam, M S; McNabola, A

2015-01-01

368

Hybrid integrated InGaAsP-Si laser using selective area metal bonding method for optical interconnection  

NASA Astrophysics Data System (ADS)

An evanescently-coupled, hybrid InGaAsP-Si laser operating at 1.55 ?m is presented by selective area metal bonding (SAMB). The III-V laser, fabricated on a p-InP substrate with a semi-insulating InP:Fe buried heterostructure (BH), serves to provide optical gain. On the SOI wafer, a 3-?m wide and 500-nm high Si waveguide is formed and the bonding metal (AuSn alloy) is selectively deposited in the regions 6 ?m away from the Si waveguide on each side. The InGaAsP gain structure is flip-chip bonded onto the patterned SOI wafer using SAMB method which separates laterally the optical coupling area and the metal bonding area to avoid strong light absorption by the bonding metal. The hybrid laser runs with a maximum single-sided output power of 9 mw at room temperature. The slope efficiency of the hybrid laser is about 0.04 W/A, 4 times that of the laser before bonding which indicates that the light confinement is improved after the bonding. The hybrid laser has achieved 10 癈 contimuous wave (CW) lasing. A near-field image of the hybrid laser is studied. As the inject current increases, the light spot markedly shifts down to the Si waveguide and covers the Si waveguide region, which demonstrates that the light generated in the III-V active region is coupled into the Si waveguide. This method allows for different III-V devices to be bonded onto any desired places on a SOI substrate. The simplicity and flexibility of the fabrication process and high yield make the hybrid laser a promising light source.

Yu, Hong-Yan; Yuan, Li-Jun; Tao, Li; Wang, Bao-Jun; Chen, Wei-Xi; Liang, Song; Li, Yan-Ping; Ran, Guang-Zhao; Pan, Jiao-Qing; Wang, Wei

2014-03-01

369

Hybrid Support Vector Regression and Autoregressive Integrated Moving Average Models Improved by Particle Swarm Optimization for Property Crime Rates Forecasting with Economic Indicators  

PubMed Central

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

Alwee, Razana; Hj Shamsuddin, Siti Mariyam; Sallehuddin, Roselina

2013-01-01

370

HiRel: Hybrid Automated Reliability Predictor (HARP) integrated reliability tool system, (version 7.0). Volume 1: HARP introduction and user's guide  

NASA Technical Reports Server (NTRS)

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.

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

371

An Integrated Hybrid Power Supply for Off-Grid Applications Fed by Wind\\/Photovoltaic\\/Fuel Cell Energy Systems  

Microsoft Academic Search

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

Hossein Kord; Ahmad Rohani

372

Rule based algorithm for Plug-in Hybrid Electric Vehicles (PHEVs) integration in residential electric grid areas  

Microsoft Academic Search

The Plug-in Hybrid Electric Vehicles (PHEVs) will strongly penetrate in the car fleet for the coming years. Based on databases of the houses Daily Loads Profiles (DLPs) build from real electricity consumption of domestic's electrical devices, this paper determines the minimal load power of PHEVs which assures the complete recharge of batteries before the next reuse of vehicles while avoiding

Harun Turker; Ahmad Hably; Seddik Bacha; Daniel Chatroux

2012-01-01

373

Statistical maritime radar duct estimation using hybrid genetic algorithmMarkov  

E-print Network

Statistical maritime radar duct estimation using hybrid genetic algorithm颅Markov chain Monte Carlo estimation using hybrid genetic algorithm颅Markov chain Monte Carlo method, Radio Sci., 42, RS3014, doi:10 work, genetic algorithms (GA) and Markov chain Monte Carlo (MCMC) samplers were used to calculate

Buckingham, Michael

374

A PDMS/paper/glass hybrid microfluidic biochip integrated with aptamer-functionalized graphene oxide nano-biosensors for one-step multiplexed pathogen detection.  

PubMed

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

Zuo, Peng; Li, XiuJun; Dominguez, Delfina C; Ye, Bang-Ce

2013-10-01

375

A PDMS/paper/glass hybrid microfluidic biochip integrated with aptamer-functionalized graphene oxide nano-biosensors for one-step multiplexed pathogen detection  

PubMed Central

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 憈urn 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

Zuo, Peng; Dominguez, Delfina C.; Ye, Bang-Ce

2014-01-01

376

Monte Carlo EM for Generalized Linear Mixed Models using Randomized Spherical Radial  

E-print Network

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

Booth, James

377

Optimally combining sampling techniques for Monte Carlo rendering  

Microsoft Academic Search

Monte Carlo integration is a powerful technique for the evaluation of difficult integrals. Applications in rendering include distribution ray tracing, Monte Carlo path tracing, and form-factor computation for radiosity methods. In these cases variance can often be signifi- cantly reduced by drawing samples from several distributions, each designed to sample well some difficult aspect of the integrand. Nor- mally this

Eric Veach; Leonidas J. Guibas

1995-01-01

378

Sewage treatment using an integrated system consisting of anaerobic hybrid reactor (AHR) and downflow hanging sponge (DHS)  

Microsoft Academic Search

This paper presents an evaluation of a combined wastewater treatment train consisting of an anaerobic hybrid reactor (AHR) followed by a downflow hanging sponge (DHS) system. The combined system was operated at a total constant hydraulic retention time (HRT) of 8 h (AHR: 6.0 h and DHS: 2.0 h) and an average organic loading rate of 1.9 kg COD\\/m.d for

M. Mahmoud; A. Tawfik; F. Samhan; F. El-Gohary

2009-01-01

379

Monte Carlo Methods Geoff Gordon  

E-print Network

Monte Carlo Methods Geoff Gordon ggordon@cs.cmu.edu February 9, 2006 #12;Numerical integration(-T(x)) As , have ExP (x) x Simulated annealing: track E(x) = xP(x)dx as #12;Used for: Bayes net inference Undirected Bayes net on x = x1, x2, . . .: P(x) = 1 Z j j(x) Typical inference problem: compute E(xi) Belief

Guestrin, Carlos

380

Integration  

ERIC Educational Resources Information Center

Integrated learning is an exciting adventure for both teachers and students. It is not uncommon to observe the integration of academic subjects such as math, science, and language arts. However, educators need to recognize that movement experiences in physical education also can be linked to academic curricula and, may even lead the

Kalyn, Brenda

2006-01-01

381

Optical phase modulation beam steering using silicon micromachined and hybrid integrated Micro-Electro-Mechanical Systems (MEMS)  

Microsoft Academic Search

Micro-Electro-Mechanical Systems (MEMS) are integrated micrometer-sized devices or systems that combine electrical and mechanical components. Integrated circuit (IC) technology is used for batch fabrication of mechanical and electrical devices in the from micrometer to millimeter. The research and development of optical beam steering devices using MEMS is presented in this thesis. Phase modulation beam steering techniques including phased array and

Adisorn Tuantranont

2001-01-01

382

Use of a Single Hybrid Imaging Agent for Integration of Target Validation with In Vivo and Ex Vivo Imaging of Mouse Tumor Lesions Resembling Human DCIS  

PubMed Central

Screening of biomarker expression levels in tumor biopsy samples not only provides an assessment of prognostic and predictive factors, but may also be used for selection of biomarker-specific imaging strategies. To assess the feasibility of using a biopsy specimen for a personalized selection of an imaging agent, the chemokine receptor 4 (CXCR4) was used as a reference biomarker. Methods A hybrid CXCR4 targeting peptide (MSAP-Ac-TZ14011) containing a fluorescent dye and a chelate for radioactive labeling was used to directly compare initial flow cytometry朾ased target validation in fresh tumor tissue to in vivo single photon emission computed tomography (SPECT) imaging and in vivo and ex vivo fluorescence imaging. Results Flow cytometric analysis of mouse tumor derived cell suspensions enabled discrimination between 4T1 control tumor lesions (with low levels of CXCR4 expression) and CXCR4 positive early, intermediate and late stage MIN-O lesions based on their CXCR4 expression levels; CXCR4basal, CXCR4+ and CXCR4++ cell populations could be accurately discriminated. Mean fluorescent intensity ratios between expression in MIN-O and 4T1 tissue found with flow cytometry were comparable to ratios obtained with in vivo SPECT/CT and fluorescence imaging, ex vivo fluorescence evaluation and standard immunohistochemistry. Conclusion The hybrid nature of a targeting imaging agent like MSAP-Ac-TZ14011 enables integration of target selection, in vivo imaging and ex vivo validation using a single agent. The use of biopsy tissue for biomarker screening can readily be expanded to other targeting hybrid imaging agents and can possibly help increase the clinical applicability of tumor-specific imaging approaches. PMID:23326303

Buckle, Tessa; Kuil, Joeri; van den Berg, Nynke S.; Bunschoten, Anton; Lamb, Hildo J.; Yuan, Hushan; Josephson, Lee; Jonkers, Jos; Borowsky, Alexander D.; van Leeuwen, Fijs W. B.

2013-01-01

383

a Hybrid Volume Integral-Finite Elements Approach for the Simulation of Eddy Current Inspection of Steam Generator Tubes in the Region of Quadrifoiled Support Plate  

NASA Astrophysics Data System (ADS)

A hybrid Volume Integral Method (VIM)桭inite Elements Method (FEM) model for the numerical modeling of eddy current inspection of steam generator (SG) tubes near quadrifoiled tube support plates (TSP) is presented. The coupled approach combines the flexibility of the FEM in modeling complex geometries with the numerical efficiency of the VIM, reducing the computational time demanded for the solution of the problem. Material deposit in the TSP openings, responsible for clogging up effects, can also be taken into account with this approach and will be considered in a next stage. The present work is conducted in the context of the further development of the CIVA nondestructive evaluation simulation platform, notably within the undertaken developments concerning coupled FEM-VIM calculations.

Skarlatos, A.; Gilles-Pascaud, C.; Pichenot, G.; Cattiaux, G.; Sollier, T.

2010-02-01

384

Improved conversion efficiency of as-grown InGaN/GaN quantum-well solar cells for hybrid integration  

NASA Astrophysics Data System (ADS)

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.

Valdueza-Felip, Sirona; Mukhtarova, Anna; Grenet, Louis; Bougerol, Catherine; Durand, Christophe; Eymery, Joel; Monroy, Eva

2014-03-01

385

High responsivity and wide bandwidth operation of InP-based pin-photodiode array monolithically integrated with 90 hybrid using butt-joint regrowth  

NASA Astrophysics Data System (ADS)

The InP-based pin-photodiode array monolithically integrated with a 90 hybrid consisting of multimode interference structures was fabricated using the butt-joint regrowth for compact 100 Gbps coherent receivers. The low dark current of less than 0.2 nA was obtained with InP passivation effect through the selective regrowth process in four-channel photodiodes. A responsivity including total loss of 8.3 dB in the waveguide was as high as 0.14 A/W. The wide 3 dB bandwidth of 24 GHz at a low reverse bias voltage of 1.6 V was also achieved under high optical input power conditions (photocurrent: 4 mA).

Yagi, Hideki; Inoue, Naoko; Masuyama, Ryuji; Katsuyama, Tomokazu; Kikuchi, Takehiko; Onishi, Yutaka; Yoneda, Yoshihiro; Shoji, Hajime

2014-02-01

386

Constructing one-dimensional silver nanowire-doped reduced graphene oxide integrated with CdS nanowire network hybrid structures toward artificial photosynthesis  

NASA Astrophysics Data System (ADS)

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

Liu, Siqi; Weng, Bo; Tang, Zi-Rong; Xu, Yi-Jun

2014-12-01

387

Architecture based on the integration of intermolecular G-quadruplex structure with sticky-end pairing and colorimetric detection of DNA hybridization  

NASA Astrophysics Data System (ADS)

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

Li, Hongbo; Wu, Zai-Sheng; Shen, Zhifa; Shen, Guoli; Yu, Ruqin

2014-01-01

388

Integration of hybridization-based markers (overgos) into physical maps for comparative and evolutionary explorations in the genus Oryza and in Sorghum  

PubMed Central

Background With the completion of the genome sequence for rice (Oryza sativa L.), the focus of rice genomics research has shifted to the comparison of the rice genome with genomes of other species for gene cloning, breeding, and evolutionary studies. The genus Oryza includes 23 species that shared a common ancestor 810 million years ago making this an ideal model for investigations into the processes underlying domestication, as many of the Oryza species are still undergoing domestication. This study integrates high-throughput, hybridization-based markers with BAC end sequence and fingerprint data to construct physical maps of rice chromosome 1 orthologues in two wild Oryza species. Similar studies were undertaken in Sorghum bicolor, a species which diverged from cultivated rice 4050 million years ago. Results Overgo markers, in conjunction with fingerprint and BAC end sequence data, were used to build sequence-ready BAC contigs for two wild Oryza species. The markers drove contig merges to construct physical maps syntenic to rice chromosome 1 in the wild species and provided evidence for at least one rearrangement on chromosome 1 of the O. sativa versus Oryza officinalis comparative map. When rice overgos were aligned to available S. bicolor sequence, 29% of the overgos aligned with three or fewer mismatches; of these, 41% gave positive hybridization signals. Overgo hybridization patterns supported colinearity of loci in regions of sorghum chromosome 3 and rice chromosome 1 and suggested that a possible genomic inversion occurred in this syntenic region in one of the two genomes after the divergence of S. bicolor and O. sativa. Conclusion The results of this study emphasize the importance of identifying conserved sequences in the reference sequence when designing overgo probes in order for those probes to hybridize successfully in distantly related species. As interspecific markers, overgos can be used successfully to construct physical maps in species which diverged less than 8 million years ago, and can be used in a more limited fashion to examine colinearity among species which diverged as much as 40 million years ago. Additionally, overgos are able to provide evidence of genomic rearrangements in comparative physical mapping studies. PMID:16895597

Hass-Jacobus, Barbara L; Futrell-Griggs, Montona; Abernathy, Brian; Westerman, Rick; Goicoechea, Jose-Luis; Stein, Joshua; Klein, Patricia; Hurwitz, Bonnie; Zhou, Bin; Rakhshan, Fariborz; Sanyal, Abhijit; Gill, Navdeep; Lin, Jer-Young; Walling, Jason G; Luo, Mei Zhong; Ammiraju, Jetty Siva S; Kudrna, Dave; Kim, Hye Ran; Ware, Doreen; Wing, Rod A; Miguel, Phillip San; Jackson, Scott A

2006-01-01

389

Designing integrated guidance law for aerodynamic missiles by hybrid multi-objective evolutionary algorithm and tabu search  

Microsoft Academic Search

In this paper, a strength Pareto evolutionary algorithm (SPEA) based approach is proposed for designing an integrated fuzzy guidance law which consists of three fuzzy controllers. Each of these controllers is activated in a region of the interception. The distribution of the membership functions and the rules are obtained by solving a nonlinear constrained multi-objective optimization problem where final time,

Hanafy M. Omar; M. A. Abido

2010-01-01

390

Correction: Fabrication of high performance flexible micro-supercapacitor arrays with hybrid electrodes of MWNT/V2O5 nanowires integrated with a SnO2 nanowire UV sensor  

NASA Astrophysics Data System (ADS)

Correction for `Fabrication of high performance flexible micro-supercapacitor arrays with hybrid electrodes of MWNT/V2O5 nanowires integrated with a SnO2 nanowire UV sensor' by Daeil Kim et al., Nanoscale, 2014, 6, 12034-12041.

Kim, Daeil; Yun, Junyeong; Lee, Geumbee; Sook Ha, Jeong

2014-11-01

391

Correction: Fabrication of high performance flexible micro-supercapacitor arrays with hybrid electrodes of MWNT/V2O5 nanowires integrated with a SnO2 nanowire UV sensor.  

PubMed

Correction for 'Fabrication of high performance flexible micro-supercapacitor arrays with hybrid electrodes of MWNT/V2O5 nanowires integrated with a SnO2 nanowire UV sensor' by Daeil Kim et al., Nanoscale, 2014, 6, 12034-12041. PMID:25365523

Kim, Daeil; Yun, Junyeong; Lee, Geumbee; Sook Ha, Jeong

2014-12-21

392

IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 23, NO. 3, JULY 2008 1527 A Quasi-Monte Carlo Integration Method Applied to  

E-print Network

Method Applied to the Computation of the Pollaczek Integral Xavier Legrand, Member, IEEE, Alain X茅mard-00116-2007. X. Legrand and A. X茅mard are with EDF R&D, Clamart 92141, France (e-mail: xavier.legrand

Paris-Sud XI, Universit茅 de

393

VERIFICATION OF THE SHIFT MONTE CARLO CODE  

SciTech Connect

Shift is a new hybrid Monte Carlo/deterministic radiation transport code being developed at Oak Ridge National Laboratory. At its current stage of development, Shift includes a fully-functional parallel Monte Carlo capability for simulating eigenvalue and fixed-source multigroup transport problems. This paper focuses on recent efforts to verify Shift s Monte Carlo component using the two-dimensional and three-dimensional C5G7 NEA benchmark problems. Comparisons were made between the benchmark eigenvalues and those output by the Shift code. In addition, mesh-based scalar flux tally results generated by Shift were compared to those obtained using MCNP5 on an identical model and tally grid. The Shift-generated eigenvalues were within three standard deviations of the benchmark and MCNP5 values in all cases. The flux tallies generated by Shift were found to be in very good agreement with those from MCNP

Sly, Nicholas [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Mervin, Mervin Brenden [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Mosher, Scott W [ORNL] [ORNL; Evans, Thomas M [ORNL] [ORNL; Wagner, John C [ORNL] [ORNL; Maldonado, G. Ivan [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK)

2012-01-01

394

Bayesian adaptive Markov chain Monte Carlo estimation of genetic parameters.  

PubMed

Accurate and fast estimation of genetic parameters that underlie quantitative traits using mixed linear models with additive and dominance effects is of great importance in both natural and breeding populations. Here, we propose a new fast adaptive Markov chain Monte Carlo (MCMC) sampling algorithm for the estimation of genetic parameters in the linear mixed model with several random effects. In the learning phase of our algorithm, we use the hybrid Gibbs sampler to learn the covariance structure of the variance components. In the second phase of the algorithm, we use this covariance structure to formulate an effective proposal distribution for a Metropolis-Hastings algorithm, which uses a likelihood function in which the random effects have been integrated out. Compared with the hybrid Gibbs sampler, the new algorithm had better mixing properties and was approximately twice as fast to run. Our new algorithm was able to detect different modes in the posterior distribution. In addition, the posterior mode estimates from the adaptive MCMC method were close to the REML (residual maximum likelihood) estimates. Moreover, our exponential prior for inverse variance components was vague and enabled the estimated mode of the posterior variance to be practically zero, which was in agreement with the support from the likelihood (in the case of no dominance). The method performance is illustrated using simulated data sets with replicates and field data in barley. PMID:22805656

Mathew, B; Bauer, A M; Koistinen, P; Reetz, T C; L閛n, J; Sillanp滗, M J

2012-10-01

395

HiRel: Hybrid Automated Reliability Predictor (HARP) integrated reliability tool system, (version 7.0). Volume 3: HARP Graphics Oriented (GO) input user's guide  

NASA Technical Reports Server (NTRS)

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 preprocessor Graphics Oriented (GO) program. GO is a graphical user interface for the HARP engine that enables the drawing of reliability/availability models on a monitor. A mouse is used to select fault tree gates or Markov graphical symbols from a menu for drawing.

Bavuso, Salvatore J.; Rothmann, Elizabeth; Mittal, Nitin; Koppen, Sandra Howell

1994-01-01

396

HiRel: Hybrid Automated Reliability Predictor (HARP) integrated reliability tool system, (version 7.0). Volume 4: HARP Output (HARPO) graphics display user's guide  

NASA Technical Reports Server (NTRS)

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.

Sproles, Darrell W.; Bavuso, Salvatore J.

1994-01-01

397

Physical and organizational provision for installation, regulatory requirements and implementation of a simultaneous hybrid PET/MR-imaging system in an integrated research and clinical setting.  

PubMed

The implementation of hybrid imaging systems requires thorough and anticipatory planning at local and regional levels. For installation of combined positron emission and magnetic resonance imaging systems (PET/MRI), a number of physical and constructional provisions concerning shielding of electromagnetic fields (RF- and high-field) as well as handling of radionuclides have to be met, the latter of which includes shielding for the emitted 511 keV gamma rays. Based on our experiences with a SIEMENS Biograph mMR system, a step-by-step approach is required to allow a trouble-free installation. In this article, we present a proposal for a standardized step-by-step plan to accomplish the installation of a combined PET/MRI system. Moreover, guidelines for the smooth operation of combined PET/MRI in an integrated research and clinical setting will be proposed. Overall, the most important preconditions for the successful implementation of PET/MRI in an integrated research and clinical setting is the interdisciplinary target-oriented cooperation between nuclear medicine, radiology, and all referring and collaborating institutions at all levels of interaction (personnel, imaging protocols, reporting, selection of the data transfer and communication methods). PMID:23053713

Sattler, Bernhard; Jochimsen, Thies; Barthel, Henryk; Sommerfeld, Kerstin; Stumpp, Patrick; Hoffmann, Karl-Titus; Gutberlet, Matthias; Villringer, Arno; Kahn, Thomas; Sabri, Osama

2013-02-01

398

Fermentative production of poly (?-glutamic acid) from renewable carbon source and downstream purification through a continuous membrane-integrated hybrid process.  

PubMed

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 0.91g/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

Kumar, Ramesh; Pal, Parimal

2015-02-01

399

ITS version 5.0 :the integrated TIGER series of coupled electron/Photon monte carlo transport codes with CAD geometry.  

SciTech Connect

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.

Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

2005-09-01

400

Analyze of 3D fluid driven crack in saturated porous media under P- and S-waves by hybrid hypersingular integral method  

NASA Astrophysics Data System (ADS)

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.

Zhu, B. J.; Shi, Y. L.; Sukop, M. C.

2009-04-01

401

Mineralogy of Libya Montes, Mars  

NASA Astrophysics Data System (ADS)

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 祄, 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 祄. 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 祄. 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 祄. 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 祄 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.

Perry, K. A.; Bishop, J. L.; McKeown, N. K.

2009-12-01

402

Ray Microcanonical Monte Carlo Model  

NSDL National Science Digital Library

The Ray Microcanonical Monte Carlo Model implements microcanonical simulations, with the Lennard-Jones potential, by integrating the kinetic contributions to the Hamiltonian and sampling the configuration space. This model is based on a method developed by John R. Ray. The input fields are editable allowing the study of different regions of the phase diagram. Radial distribution functions are displayed and average thermodynamic properties and their fluctuations are displayed. The Ray Microcanonical Monte Carlo Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Fernandes, Fernando S.

2012-12-10

403

Hybrid Elastic and Discrete-Particle Approach to Biomembrane Dynamics with Application to the Mobility of Curved Integral Membrane Proteins  

NASA Astrophysics Data System (ADS)

We introduce a simulation strategy to consistently couple continuum biomembrane dynamics to the motion of discrete biological macromolecules residing within or on the membrane. The methodology is used to study the diffusion of integral membrane proteins that impart a curvature on the bilayer surrounding them. Such proteins exhibit a substantial reduction in diffusion coefficient relative to 揻lat proteins; this effect is explained by elementary hydrodynamic considerations.

Naji, Ali; Atzberger, Paul J.; Brown, Frank L. H.

2009-04-01

404

Evaporation-Induced Self-Assembly of Hybrid Bridged Silsesquioxane Film and Particulate Mesophases with Integral Organic Functionality  

Microsoft Academic Search

Since the discovery of surfactant-templated silica mesophases, the development of organic modification schemes to impart functionality to the pore surfaces has received much attention. Most recently, using the general class of compounds referred to as bridged silsesquioxanes (RO)釹i-R獠-Si(OR) (Scheme 1), three research groups have reported the formation of a new class of poly(bridgedsilsesquioxane) mesophases BSQMs with integral organic functionality. In

YUNFENG LU; HONGYOU FAN; NILESH DOKE; DOUGLAS A. LOY; ROGER A. ASSINK; DAVID A. LAVAN; C. JEFFREY BRINKER

2000-01-01

405

Integration  

NSDL National Science Digital Library

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.

2013-06-21

406

Scalable integration of Li5FeO4 towards robust, high-performance lithium-ion hybrid capacitors.  

PubMed

Lithium-ion hybrid capacitors have attracted great interest due to their high specific energy relative to conventional electrical double-layer capacitors. Nevertheless, the safety issue still remains a drawback for lithium-ion capacitors in practical operational environments because of the use of metallic lithium. Herein, single-phase Li5FeO4 with an antifluorite structure that acts as an alternative lithium source (instead of metallic lithium) is employed and its potential use for lithium-ion capacitors is verified. Abundant Li(+) amounts can be extracted from Li5FeO4 incorporated in the positive electrode and efficiently doped into the negative electrode during the first electrochemical charging. After the first Li(+) extraction, Li(+) does not return to the Li5FeO4 host structure and is steadily involved in the electrochemical reactions of the negative electrode during subsequent cycling. Various electrochemical and structural analyses support its superior characteristics for use as a promising lithium source. This versatile approach can yield a sufficient Li(+)-doping efficiency of >90% and improved safety as a result of the removal of metallic lithium from the cell. PMID:25208971

Park, Min-Sik; Lim, Young-Geun; Hwang, Soo Min; Kim, Jung Ho; Kim, Jeom-Soo; Dou, Shi Xue; Cho, Jaephil; Kim, Young-Jun

2014-11-01

407

Discrete diffusion Monte Carlo for frequency-dependent radiative transfer  

SciTech Connect

Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Implicit Monte Carlo radiative-transfer simulations. In this paper, we develop 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. Above this threshold we employ standard Monte Carlo. With a frequency-dependent test problem, we confirm the increased efficiency of our new DDMC technique.

Densmore, Jeffrey D [Los Alamos National Laboratory; Kelly, Thompson G [Los Alamos National Laboratory; Urbatish, Todd J [Los Alamos National Laboratory

2010-11-17

408

On-chip hybrid photonic-plasmonic light concentrator for nanofocusing in an integrated silicon photonics platform.  

PubMed

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

Luo, Ye; Chamanzar, Maysamreza; Apuzzo, Aniello; Salas-Montiel, Rafael; Nguyen, Kim Ngoc; Blaize, Sylvain; Adibi, Ali

2015-02-11

409

Monte Carlo fundamentals  

SciTech Connect

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.

Brown, F.B.; Sutton, T.M.

1996-02-01

410

Markov Chain Monte Carlo Methods Markov Chain Monte Carlo Methods  

E-print Network

Markov Chain Monte Carlo Methods Markov Chain Monte Carlo Methods Christian P. Robert Universit Monte Carlo Methods Textbook: Monte Carlo Statistical Methods by Christian. P. Robert and George Casella Monte Carlo Methods with R by Christian. P. Robert and George Casella [trad. fran赂caise 2010; japonaise

Robert, Christian P.

411

Markov Chain Monte Carlo Methods Markov Chain Monte Carlo Methods  

E-print Network

Markov Chain Monte Carlo Methods Markov Chain Monte Carlo Methods Christian P. Robert Universit Monte Carlo Methods Outline Motivation and leading example Random variable generation Monte Carlo for variable dimension problems Sequential importance sampling #12;Markov Chain Monte Carlo Methods New [2004

Robert, Christian P.

412

THE MONTE CARLO ALGORITHM WITH A PSEUDO--RANDOM GENERATOR  

E-print Network

write the Monte Carlo algorithm with a pseudo颅random generator. When the distribution ae is uniform, i.eTHE MONTE CARLO ALGORITHM WITH A PSEUDO--RANDOM GENERATOR J. F. Traub Department of Computer Carlo algorithm for the approximation of multivariate integrals when a pseudo颅random generator is used

Traub, Joseph F.

413

Quantum Monte Carlo Method for Attractive Coulomb Potentials  

E-print Network

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.

J. S. Kole; H. De Raedt

2001-02-06

414

Recent Advances in Randomized Quasi-Monte Carlo Methods  

Microsoft Academic Search

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

Pierre L扙cuyer; Christiane Lemieux

415

Inverse Monte Carlo: a unified reconstruction algorithm for SPECT  

Microsoft Academic Search

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

Carey E. Floyd; R. E. Coleman; R. J. Jaszczak

1985-01-01

416

Finite Time Analysis of Stratified Sampling for Monte Carlo  

E-print Network

Finite Time Analysis of Stratified Sampling for Monte Carlo Alexandra Carpentier INRIA Lille - Nord We consider the problem of stratified sampling for Monte-Carlo integration. We model this problem the final estimation error. This example is just one of many for which an efficient method of sampling

Boyer, Edmond

417

STP Monte Carlo Estimation  

NSDL National Science Digital Library

The STP MonteCarloEstimation program estimates the area under the curve given by the square-root of (1-x^2) between 0 and 1 using the Monte Carlo hit and miss method. STP MonteCarloEstimation is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double clicking the stp_MonteCarloEstimation.jar file will run the program if Java is installed on your computer.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-01-26

418

Hybrid solar-fossil fuel power generation  

E-print Network

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 ...

Sheu, Elysia J. (Elysia Ja-Zeng)

2012-01-01

419

Analytical insights into the partially integrated transport modeling method for hybrid Reynolds averaged Navier-Stokes equations-large eddy simulations of turbulent flows  

NASA Astrophysics Data System (ADS)

The basis of the partially integrated transport modeling (PITM) method was introduced by Schiestel and Dejoan ["Towards a new partially integrated transport model for coarse grid and unsteady turbulent flow simulations," Theor. Comput. Fluid Dyn. 18, 443 (2005)], 10.1007/s00162-004-0155-z and Chaouat and Schiestel ["A new partially integrated transport model for subgrid-scale stresses and dissipation rate for turbulent developing flows," Phys. Fluids 17, 065106 (2005)], 10.1063/1.1928607. This method provides a continuous approach for hybrid RANS-LES (Reynolds averaged Navier-Stokes equations-large eddy simulations) simulations with seamless coupling between RANS and LES regions. The main ingredient of the method is the new dissipation-rate equation that can be applied as a subfilter scale turbulence model. Then, it becomes easy to convert almost any usual RANS transport model into a subfilter scale model. In particular, the method can be applied to two equation models and to stress transport models as well. In the derivation of the method, the partial integration technique allows to keep a link between the spectral space and the physical space of the resulting model. The physical turbulent processes involving the production, dissipation, and flux transfer of the turbulent energy are introduced in the equations. The present work, after recalling the main building steps of the PITM method, brings further insight into the physical interpretation of the method, its underlying hypotheses and its internal acting mechanisms. In particular, the finiteness of the coefficients used in the dissipation-rate equation is discussed in detail from a theoretical point of view. Then, we consider the analytical example of self-similar turbulent flow for analyzing the dissipation-rate equation. From an analytical solution obtained by Taylor series expansions taking into account the Kovasznay hypothesis for evaluating the transfer term, we compute the functional coefficients c_{{? }_2} and c_{sfs{? }_2} used in RANS and LES methodologies, respectively, and we demonstrate that both coefficients take on finite values when the Reynolds number goes to infinity. Finally, after briefly mentioning some flow illustrations to get a real appraisal of the PITM method in its capabilities to simulate unsteady flows on relatively coarse grids with a sufficient accuracy for engineering computations, we study the coefficient c_{sfs{? }_2} through one chosen example.

Chaouat, Bruno; Schiestel, Roland

2012-08-01

420

A Chance at Monte Carlo  

NSDL National Science Digital Library

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梩he numerical value of the most famous irrational number, ?.

2014-09-18

421

TRISO Fuel Performance: Modeling, Integration into Mainstream Design Studies, and Application to a Thorium-fueled Fusion-Fission Hybrid Blanket  

SciTech Connect

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.

Powers, J J

2011-11-28

422

TRISO Fuel Performance: Modeling, Integration into Mainstream Design Studies, and Application to a Thorium-fueled Fusion-Fission Hybrid Blanket  

NASA Astrophysics Data System (ADS)

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.

Powers, Jeffrey J.

2011-12-01

423

Optical properties of tumor tissues grown on the chorioallantoic membrane of chicken eggs measured with a double integrating sphere and inverse Monte Carlo method in the wavelength range of 350-1000 nm  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) is an attractive method because of the shorter decay time of photosensitivity compared with PDT using other drugs. However, the optimum conditions to perform ALA-PDT, e.g., drug dose, wavelength, and irradiation dose have never been clarified. To evaluate the effectiveness of PDT using ALA and its dependence on drug dose, wavelength, and irradiation dose in the treatment of tumors, the usefulness of a tumor model prepared with tumor cells grown on the chorioallantoic membrane of chicken eggs was studied by measuring the optical properties of the tumor model. The optical properties of tumor model were measured with a double integrating sphere optical setup and inverse Monte Carlo technique in the wavelength range from 350 to 1000 nm. The spectra of absorption and reduced scattering coefficients of the tumor model grown in the chicken eggs were compared with those of the other tumor model grown in mice. The measured optical properties of the tumor model using chicken eggs were similar to those of the tumor model using mice. These results indicate that the tumor model using chicken eggs is a suitable system to investigate the effectiveness of ALA-PDT. This in vivo assay system for tumors has advantages for evaluating antitumor effect of ALA-PDT because of its convenience, rapidity, and inexpensiveness.

Honda, Norihiro; Kariyama, Yoichiro; Ishii, Takuya; Abe, Chiaki; Inoue, Katsushi; Ishizuka, Masahiro; Tanaka, Tohru; Hazama, Hisanao; Awazu, Kunio

2013-02-01

424

Monte Carlo method in optical radiometry  

Microsoft Academic Search

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

A. V. Prokhorov

1998-01-01

425

Dosimetry Calculations Using Markov Chain Monte  

Microsoft Academic Search

SUMMARY A new numerical method for solving the inverse problem of in- ternal dosimetry is described. The new method uses Markov Chain Monte Carlo and the Metropolis algorithm. Multiple intake amounts, biokinetic types, and times of intake are determined from bioas- say data by integrating over the Bayesian posterior distribution. The method appears definitive, but its application requires a large

Guthrie Miller; Harry F. Martz; Tom T. Little; Ray Guilmette

426

Monte Carlo simulations of dense quantum plasmas  

Microsoft Academic Search

Thermodynamic properties of the equilibrium strongly coupled quantum plasmas investigated by direct path integral Monte Carlo (DPIMC) simulations within a wide region of density, temperature and positive to negative particle mass ratio. Pair distribution functions (PDF), equation of state (EOS), internal energy and Hugoniot are compared with available theoretical and experimental results. Possibilities of the phase transition in hydrogen and

V. S. Filinov; M. Bonitz; V. E. Fortov; W. Ebeling; H. Fehske; D. Kremp; W. D. Kraeft; V. Bezkrovniy; P. Levashov

2006-01-01

427

Hybrid Interventions in Limb Salvage  

PubMed Central

Hybrid interventions have become an integral part of our strategy for limb salvage in patients with multilevel arterial occlusive disease. In this article, we describe the commonly used hybrid interventions and review their indications and outcomes. Iliac stenting and femoral endarterectomy are the two most frequently performed procedures in hybrid cases. Short- and long-term outcomes of hybrid interventions are at least comparable to conventional endovascular and surgical revascularization procedures. Hybrid revascularization offers the efficiency and convenience of a single-stage revascularization. PMID:23805341

Huynh, Tam T.T.; Bechara, Carlos F.

2013-01-01

428

High-coherence semiconductor lasers based on integral high-Q resonators in hybrid Si/III-V platforms  

PubMed Central

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

Santis, Christos Theodoros; Steger, Scott T.; Vilenchik, Yaakov; Vasilyev, Arseny; Yariv, Amnon

2014-01-01

429

High-coherence semiconductor lasers based on integral high-Q resonators in hybrid Si/III-V platforms.  

PubMed

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 10(6). PMID:24516134

Santis, Christos Theodoros; Steger, Scott T; Vilenchik, Yaakov; Vasilyev, Arseny; Yariv, Amnon

2014-02-25

430

Analytical finite element matrix elements and global matrix assembly for hierarchical 3-D vector basis functions within the hybrid finite element boundary integral method  

NASA Astrophysics Data System (ADS)

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.

Li, L.; Wang, K.; Li, H.; Eibert, T. F.

2014-11-01

431

Symbolic Implicit Monte Carlo  

Microsoft Academic Search

We introduce a new implicit Monte Carlo technique for solving time dependent radiation transport problems involving spontaneous emission. In the usual implicit Monte Carlo procedure an effective scattering term in dictated by the requirement of self-consistency between the transport and implicitly differenced atomic populations equations. The effective scattering term, a source of inefficiency for optically thick problems, becomes an impasse

Eugene D. Brooks III

1989-01-01

432

Monte Carlo POMDPs Sebastian Thrun  

E-print Network

Monte Carlo POMDPs Sebastian Thrun School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Abstract We present a Monte Carlo algorithm for learning to act in partially observable sampling forrepresentingbeliefs, and Monte Carlo approximation for belief propagation. A reinforcement

Thrun, Sebastian

433

Optimally combining sampling tech-niques for Monte Carlo rendering  

Microsoft Academic Search

Monte Carlo integration is a powerful technique for the evaluation of difficult integrals. Applications in rendering include distribution ray tracing, Monte Carlo path tracing, and form-factor computation for radiosity methods. In these cases variance can often be signifi-cantly reduced by drawing samples from several distributions, each designed to sample well some difficult aspect of the integrand. Nor-mally this is done

E. Veach; L. Guibas

1994-01-01

434

Quantum Monte Carlo Simulations of Solid 4 P.A. Whitlock1  

E-print Network

Quantum Monte Carlo Simulations of Solid 4 He P.A. Whitlock1 and S.A. Vitiello2 1 Computer Carlo calculations at zero temperature; diffusion Monte Carlo, and finally, the finite temperature path integral Monte Carlo method. A brief introduction to the technique will be given followed by a discussion

Whitlock, Paula

435

Coupled Electron Ion Monte Carlo Calculations of Atomic Markus Holzmann a, Carlo Pierleoni b  

E-print Network

Coupled Electron Ion Monte Carlo Calculations of Atomic Hydrogen Markus Holzmann a, Carlo Pierleoni, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA Abstract We present a new Monte Carlo method which couples Path Integral for finite temperature protons with Quantum Monte Carlo for ground

436

Quasi-Monte Carlo methods for lattice systems: A first look  

NASA Astrophysics Data System (ADS)

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抯 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 = 搉umber of samples 搉umber 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.

Jansen, K.; Leovey, H.; Ammon, A.; Griewank, A.; M黮ler-Preussker, M.

2014-03-01

437

MORSE Monte Carlo code  

SciTech Connect

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.

Cramer, S.N.

1984-01-01

438

Secondproofs Monte Carlo and Quasi-Monte Carlo Methods 2008  

E-print Network

Secondproofs Monte Carlo and Quasi-Monte Carlo Methods 2008 #12;Secondproofs #12;Secondproofs Pierre L'Ecuyer r Art B. Owen Editors Monte Carlo and Quasi-Monte Carlo Methods 2008 #12;Secondproofs, CA 94305 USA owen@stanford.edu ISBN 978-3-642-04106-8 DOI 10.1007/978-3-642-04107-5 e-ISBN978

L'Ecuyer, Pierre

439

Monte Carlo methods Monte Carlo Principle and MCMC  

E-print Network

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

Doucet, Arnaud

440

Compression enhancement using the hybrid motion estimation in sub-image array transformed from elemental image array in three-dimensional integral image  

NASA Astrophysics Data System (ADS)

In this paper, we suggest the enhanced compression scheme using the hybrid motion-estimation in sub-image array (SIA) transformed from elemental image array (EIA) in three-dimensional integral imaging. In the proposed method, firstly, a macroblock in the reference sub-image (SI) is matched in the local SI applying to MSE (Motion Square Estimation) by three step search (TSS) to search the coordinates of current macro block. The second step is to search the most matched area in SIs and the coordinate of macro block for full searching, and finally, the start point for searching in the local SI is altered by the former coordinate. Accordingly, the computed motion estimation from the block-matching with TSS and the full searching is presented as MV and the object in the reference SI is shifted to the object position of each current SIs to compensate their MV based on the motion estimation. The computation time for block-matching by the TSS to search approximate current macro block range in the first step and the full searching to acquire the exact current macro block range in the second step is decreased. In addition, the video compression such as MPEG-4 is applied to encode the data of the consecutive frames. Some experiments are carried out and compression efficiency of the proposed scheme has been improved 676.30%, 357.19% and 3.37% on the condition of 30[dB] approximately, compared with the JPEG compression, EIA compression and Full searching method. The computation time is also improved 196.97% compared with the full search scheme for motion estimation and compensation.

Lee, Hyoung-Woo; Lee, Ju-Han; Kang, Ho-Hyun; Kim, Eun-Soo

2012-10-01

441

Hybridization & Conservation Natural hybridization can create genetic diversity, e.g. plant species of hybrid origin,  

E-print Network

the genetic integrity of existing species to the point of causing extinctions. New Zealand grey duck (Anas superciliosa) hybridizes with introduced mallards (Anas platyrynchos). 路 Mallards are common but NZ greys hybridization problems. Ethiopian wolf (Canis simensis) and domestic dog (C. familiaris). C. simensis has become

Creel, Scott

442

Enhancements in Continuous-Energy Monte Carlo Capabilities in SCALE  

SciTech Connect

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.

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

443

Modeling Hybrid Genetic Algorithms  

Microsoft Academic Search

This paper looks at how one form of hybrid genetic algorithm can be modeledin the context of the existing models for the simple genetic algorithm; it shouldbe possible to model the integration of other types of local search with geneticalgorithms using the same basic approach. A secondary goal of this paper is toreview the existing models for finite and infinite

Darrell Whitley

1995-01-01

444

Dynamic Modeling and Plantwide Control of a Hybrid Power and Chemical Plant: An Integrated Gasification Combined Cycle Coupled with a Methanol Plant  

NASA Astrophysics Data System (ADS)

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

Robinson, Patrick J.

445

Alternative sampling for variational quantum Monte Carlo.  

PubMed

Expectation values of physical quantities may accurately be obtained by the evaluation of integrals within many-body quantum mechanics, and these multidimensional integrals may be estimated using Monte Carlo methods. In a previous publication it has been shown that for the simplest, most commonly applied strategy in continuum quantum Monte Carlo, the random error in the resulting estimates is not well controlled. At best the central limit theorem is valid in its weakest form, and at worst it is invalid and replaced by an alternative generalized central limit theorem and non-normal random error. In both cases the random error is not controlled. Here we consider a new "residual sampling strategy" that reintroduces the central limit theorem in its strongest form, and provides full control of the random error in estimates. Estimates of the total energy and the variance of the local energy within variational Monte Carlo are considered in detail, and the approach presented may be generalized to expectation values of other operators, and to other variants of the quantum Monte Carlo method. PMID:18351957

Trail, J R

2008-01-01

446

Improved geometry representations for Monte Carlo radiation transport.  

SciTech Connect

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.

Martin, Matthew Ryan (Cornell University)

2004-08-01

447

Sufficient conditions for fast quasi-Monte Carlo convergence  

Microsoft Academic Search

We study the approximation of d-dimensional integrals. We present sucient condi- tions for fast quasi-Monte Carlo convergence. They apply to isotropic and non-isotropic problems and, in particular, to a number of problems in computational finance. We show that the convergence rate of quasi-Monte Carlo is of order n 1+p{logn} 1\\/2 with p 0. This is a worst case result. Compared

Anargyros Papageorgiou

2003-01-01

448

Baseball Monte Carlo Style.  

ERIC Educational Resources Information Center

Monte Carlo methods are used to simulate activities in baseball such as a team's "hot streak" and a hitter's "batting slump." Student participation in such simulations is viewed as a useful method of giving pupils a better understanding of the probability concepts involved. (MP)

Houser, Larry L.

1981-01-01

449

Climbing Monte Verde  

Microsoft Academic Search

Road to the top of Monte Verde, the highest peak on S鉶 Vincente. From the top of the mountain there are spectacular views of the surrounding area, including the peaks of Santa Alt鉶 and the harbor at Mindelo. At the peak of the mountain there is a radio antennae guarded by a few soldiers.

David Baxter

1981-01-01

450

Quantum Transfer Monte Carlo Method for Finite Temperature Properties and Quantum Molecular Dynamics Method for Dynamical Correlation Functions  

Microsoft Academic Search

A quantum transfer matrix method is proposed and examined. To obtain finite temperature properties, a small number of Monte Carlo samples for the trace summation is taken without the Monte Carlo sampling of the path integral. We introduce the method of a random orthonormal base in the Monte Carlo sampling. This makes it possible to investigate larger size systems than

Masatoshi Imada; Minoru Takahashi

1986-01-01

451

Application of a New Hybrid Model with Seasonal Auto-Regressive Integrated Moving Average (ARIMA) and Nonlinear Auto-Regressive Neural Network (NARNN) in Forecasting Incidence Cases of HFMD in Shenzhen, China  

PubMed Central

Background Outbreaks of hand-foot-mouth disease (HFMD) have been reported for many times in Asia during the last decades. This emerging disease has drawn worldwide attention and vigilance. Nowadays, the prevention and control of HFMD has become an imperative issue in China. Early detection and response will be helpful before it happening, using modern information technology during the epidemic. Method In this paper, a hybrid model combining seasonal auto-regressive integrated moving average (ARIMA) model and nonlinear auto-regressive neural network (NARNN) is proposed to predict the expected incidence cases from December 2012 to May 2013, using the retrospective observations obtained from China Information System for Disease Control and Prevention from January 2008 to November 2012. Results The best-fitted hybrid model was combined with seasonal ARIMA and NARNN with 15 hidden units and 5 delays. The hybrid model makes the good forecasting performance and estimates the expected incidence cases from December 2012 to May 2013, which are respectively ?965.03, ?1879.58, 4138.26, 1858.17, 4061.86 and 6163.16 with an obviously increasing trend. Conclusion The model proposed in this paper can predict the incidence trend of HFMD effectively, which could be helpful to policy makers. The usefulness of expected cases of HFMD perform not only in detecting outbreaks or providing probability statements, but also in providing decision makers with a probable trend of the variability of future observations that contains both historical and recent information. PMID:24893000

Tan, Li; Jiang, Hongbo; Wang, Ying; Wei, Sheng; Nie, Shaofa

2014-01-01

452

Monte Carlo POMDPs Sebastian Thrun  

E-print Network

Monte Carlo POMDPs Sebastian Thrun School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Abstract We present a Monte Carlo algorithm for learning to act in partially observable sampling for representing beliefs, and Monte Carlo approximation for belief propagation. A reinforcement

Thrun, Sebastian