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Modeling of operational safeguard for power productions in the nuclear power plants (NPPs)

ENERGY EXPLORATION & EXPLOITATION 2010年第6期28卷 433-449页

作者： Woo, Tae-Ho Lee, Un-Chul Seoul Natl Univ Dept Nucl Engn Seoul 151742 South Korea

Power operations for secure performance are investigated using non-linear algorithm. The object of the simulation is to find the safe operation with safeguard for the life-extension of the operations. The network effect of the game theory is used for the quantification which is incorporated with the monte-carlo method. The characteristics of the nuclear power plants (NPPs) are analyzed by the designed occurrence value as the refueling factor (RF) and the safeguard measures factor (SMF) which are used for the basic element. The random sampling for the event frequency is used by the characteristics of network effect method like the zero-sum quantification, because it is impossible to expect the time of terror incident exactly. Three kinds of considerations are basic elements as the nuclear fuel, system, and safeguard properties which are organized as an aspect of safeguard considerations. The maximum value of secure operation is the 13.0 in 14(th) month and the minimum value is 1.0 in several months during 10 years. Hence, the stability of the secure power operation increases 13 times higher than the lowest value in this study. The conclusions give that the secure operation is changeable in the designed NPPs.

关键词： Nuclear Power Plants Safeguard Life-extension Network Effect monte-carlo algorithm

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monte-carlo algorithm for line-by-line calculations of thermal radiation in multiple scattering layered atmospheres

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JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER 2006年第1期98卷 107-115页

作者： Fomin, BA CPTEC INPE BR-12630000 Sao Paulo Brazil

An algorithm for calculations of the longwave radiation in cloudy and aerosol slab atmospheres is described. It is based on the line-by-line and monte-carlo methods and is suitable for accurate treatment of both the gaseous absorption and the particulate multiple scattering in any spectral regions;other published algorithms as accurate as this can only make calculations in narrow spectral regions. It is recommended that this algorithm is well suited for radiation code validations as well as for theoretical investigations of radiative transfer in clouds and aerosols and satellite signal simulations. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： atmospheric radiation longwave scattering and absorption line-by-line calculations monte-carlo algorithm

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Method of lines for stochastic boundary-value problems with additive noise

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APPLIED MATHEMATICS AND COMPUTATION 2008年第1期199卷 301-314页

作者： Roessler, Andreas Seaid, Mohammed Zahri, Mostafa Goethe Univ Frankfurt Fachbereich Math D-60054 Frankfurt Germany Tech Univ Darmstadt Fachbereich Math D-64289 Darmstadt Germany Univ Kaiserslautern Fachbereich Math D-67663 Kaiserslautern Germany

We propose a new numerical method for solving stochastic boundary-value problems. The method uses the deterministic method of lines to treat the time, space and randomness separately. The emphasis in the present study is given to stochastic partial differential equations with forced additive noise. The spatial discretization is carried out using a second-order finite volume method, while the associated stochastic differential system is numerically solved using a class of stochastic Runge-Kutta methods. The performance of the proposed methods is tested for a stochastic advection-diffusion problem and a stochastic Burgers equation driven with white noise. Numerical results are presented in both one and two space dimensions. (C) 2007 Elsevier Inc. All rights reserved.

关键词： stochastic partial differential equations method of lines stochastic Runge-Kutta schemes white noise monte-carlo algorithm

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Simulation via direct computation of partition functions

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Physical Review E 2007年第3期76卷 036708-036708页

作者： Cheng Zhang Jianpeng Ma Department of Bioengineering Rice University Houston Texas 77005 USA Verna and Marrs McLean Department of Biochemistry and Molecular Biology Baylor College of Medicine One Baylor Plaza BCM-125 Houston Texas 77030 USA

In this paper, we demonstrate the efficiency of simulations via direct computation of the partition function under various macroscopic conditions, such as different temperatures or volumes. The method can compute partition functions by flattening histograms, through, for example, the Wang-Landau recursive scheme, outside the energy space. This method offers a more general and flexible framework for handling various types of ensembles, especially ones in which computation of the density of states is not convenient. It can be easily scaled to large systems, and it is flexible in incorporating monte carlo cluster algorithms or molecular dynamics. High efficiency is shown in simulating large Ising models, in finding ground states of simple protein models, and in studying the liquid-vapor phase transition of a simple fluid. The method is very simple to implement and we expect it to be efficient in studying complex systems with rugged energy landscapes, e.g., biological macromolecules.

关键词： DENSITY-OF-STATES SPIN-GLASS SIMULATIONS monte-carlo algorithm MULTICANONICAL ENSEMBLE CANONICAL ENSEMBLE DYNAMICS LATTICE MODEL

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Structure optimization and folding mechanisms of off-lattice protein models using statistical temperature molecular dynamics simulation: Statistical temperature annealing

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Physical Review E 2007年第1期76卷 011913-011913页

作者： Jaegil Kim John E. Straub Thomas Keyes Department of Chemistry Boston University Boston Massachusetts 02215 USA

The recently proposed statistical temperature molecular dynamics (STMD) algorithm [Kim et al., Phys. Rev. Lett. 97, 050601 (2006)] is used as the core of an optimization algorithm, statistical temperature annealing (STA), for finding low-lying energy minima of complex potential energy landscapes. Since STMD realizes a random walk in energy, the idea is simply to initiate repeated minimizations from configurations in the low-energy segments of STMD trajectories. STA is tested in structural optimization of various off-lattice AB and extended AB protein models in two and three dimensions with different chain lengths. New putative ground states were found for the two- and three-dimensional AB 55-mer, and for the three-dimensional extended AB 21-mer and 55-mer. The distinct folding features of the models are analyzed in terms of the statistical temperature and other representations of the structure of the potential energy landscape. It is shown that the characteristic behavior of the statistical temperature undergoes a qualitative change with the inclusion of a torsional potential in the extended AB model, as the more rigid backbone makes the potential energy landscape more funnel-like.

关键词： monte-carlo algorithm MULTICANONICAL ENSEMBLE PHASE-SPACE TOY MODEL DISTRIBUTIONS TRANSITIONS

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Analyzing energy landscapes for folding model proteins

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JOURNAL OF CHEMICAL PHYSICS 2006年第20期124卷 4714-1-4714-1页

作者： Cox, Graham A. Johnston, Roy L. Univ Birmingham Sch Chem Birmingham B15 2TT W Midlands England

A new benchmark 20-bead HP model protein sequence (on a square lattice), which has 17 distinct but degenerate global minimum (GM) energy structures, has been studied using a genetic algorithm (GA). The relative probabilities of finding particular GM conformations are determined and related to the theoretical probability of generating these structures using a recoil growth constructor operator. It is found that for longer successful GA runs, the GM probability distribution is generally very different from the constructor probability, as other GA operators have had time to overcome any initial bias in the originally generated population of structures. Structural and metric relationships (e.g., Hamming distances) between the 17 distinct GM are investigated and used, in conjunction with data on the connectivities of the GM and the pathways that link them, to explain the GM probability distributions obtained by the GA. A comparison is made of searches where the sequence is defined in the normal (forward) and reverse directions. The ease of finding mirror image solutions are also compared. Finally, this approach is applied to rationalize the ease or difficulty of finding the GM for a number of standard benchmark HP sequences on the square lattice. It is shown that the relative probabilities of finding particular members of a set of degenerate global minima depend critically on the topography of the energy landscape in the vicinity of the GM, the connections and distances between the GM, and the nature of the operators used in the chosen search method. (c) 2006 American Institute of Physics.

关键词： COLONY OPTIMIZATION algorithm CHAIN GROWTH algorithm monte-carlo algorithm GENETIC algorithmS SIMULATIONS SPACES CODES 2D

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Computation of Greeks using Malliavin's calculus in jump type market models

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ELECTRONIC JOURNAL OF PROBABILITY 2006年第none期11卷 276-300页

作者： Bavouzet-Morel, MP Messaoud, M INRIA Rocquencourt Projet MATHFI F-78150 Le Chesnay France IXIS F-75648 Paris 13 France

We use the Malliavin calculus for Poisson processes in order to compute sensitivities for European and Asian options with underlying following a jump type diffusion. The main point is to settle an integration by parts formula ( similar to the one in the Malliavin calculus) for a general multidimensional random variable which has an absolutely continuous law with differentiable density. We give an explicit expression of the differential operators involved in this formula and this permits to simulate them and consequently to run a monte carlo algorithm.

关键词： Malliavin calculus monte-carlo algorithm Euler scheme compound Poisson process sensitivity analysis European options Asian options

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Fast monte-carlo low rank approximations for matrices

Fast Monte-Carlo low rank approximations for matrices

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IEEE/SMC International Conference on System of Systems Engineering

作者： Friedland, Shmuel Niknejad, Amir Kaveh, Mostafa Zare, Hossein Univ Illinois Dept Math Stat & Comp Sci Chicago IL 60607 USA Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA

ISBN: (纸本)9781424401871

In many applications, it is of interest to approximate data, given by m x n matrix A, by a matrix B of at most rank k, which is much smaller than m and n. The best approximation is given by singular value decomposition, which is too time consuming for very large m and n. We present here a monte carlo algorithm for iteratively computing a k-rank approximation to the data consisting of m x n matrix A. Each iteration involves the reading of O(k) of columns or rows of A. The complexity of our algorithm is O(kmn). Our algorithm, distinguished from other known algorithms, guarantees that each iteration is a better k-rank approximation than the previous iteration. We believe that this algorithm will have many applications in data mining, data storage and data analysis.

关键词： SVD decomposition fast k-rank approximation monte-carlo algorithm

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The kernel polynomial method

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Reviews of Modern Physics 2006年第1期78卷 275-275页

作者： Alexander Weiße Gerhard Wellein Andreas Alvermann Holger Fehske Institut für Physik Ernst-Moritz-Arndt-Universität Greifswald D-17487 Greifswald Germany

Efficient and stable algorithms for the calculation of spectral quantities and correlation functions are some of the key tools in computational condensed-matter physics. In this paper basic properties and recent developments of Chebyshev expansion based algorithms and the kernel polynomial method are reviewed. Characterized by a resource consumption that scales linearly with the problem dimension these methods enjoyed growing popularity over the last decade and found broad application not only in physics. Representative examples from the fields of disordered systems, strongly correlated electrons, electron-phonon interaction, and quantum spin systems are discussed in detail. In addition, an illustration on how the kernel polynomial method is successfully embedded into other numerical techniques, such as cluster perturbation theory or monte carlo simulation, is provided.

关键词： DEPENDENT SCHRODINGER-EQUATION BINDING MOLECULAR-DYNAMICS LOCAL ATOMICENVIRONMENT MAXIMUM-ENTROPY APPROACH monte-carlo algorithm DOUBLE-EXCHANGE MODEL ELECTRONIC-STRUCTURE MODIFIED-MOMENTS GAUSSIAN QUADRATURE CLASSICAL CROSSOVER

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Growth algorithm for finding low energy configurations of simple lattice proteins

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Physical Review E 2005年第1期72卷 016704-016704页

作者： Wenqi Huang Zhipeng Lü He Shi Academy of Mathematics and Systems Science in the Chinese Academy of Science Beijing 100080 China

PERM and its new variant nPERMis have been developed to optimize the energy function of protein folding based on HP simple lattice model and were found to outperform all other previous fully blind general purpose algorithms. Using the concept of core-guiding and life-forecasting, we propose a new version of nPERMis, called nPERMh. A major difference with respect to nPERMis is that criteria for further growth of new residue are based on the species of current growing monomer and its position in the HP sequence. Seventeen sequences of length ranging from 46 to 124 residues were tested by nPERMh on the cubic lattice and our algorithm proved very efficient. It should be pointed out that our new version of nPERMis is exclusively designed for conformational search. We hope that similar methods will ultimately be useful for finding native states of more realistic protein models.

关键词： monte-carlo algorithm FOLDING SIMULATIONS GLOBULAR-PROTEINS MODEL HETEROPOLYMERS KINETICS SEARCH STATE

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