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FONESYS: The FOrum & NEtwork of SYStem Thermal-Hydraulic Codes in Nuclear Reactor Thermal-Hydraulics

NUCLEAR ENGINEERING AND DESIGN 2015年第Jan.期281卷 103-113页

作者： Ahn, S. H. Aksan, N. Austregesilo, H. Bestion, D. Chung, B. D. D'Auria, F. Emonot, P. Gandrille, J. L. Hanninen, M. Horvatovic, I. Kim, K. D. Kovtonyuk, A. Petruzzi, A. KINS Yongin Gyeonggi Do South Korea Univ Pisa San Piero Grado Nucl Res Grp GRNSPG I-56100 Pisa Italy Gesell Anlagen & Reaktorsicherheit GRS Cologne Germany Commissariat Energie Atom & Energies Alternat CEA Grenoble France KAERI Taejon South Korea VTT Tech Res Ctr Finland VTT Espoo Finland

The purpose of this article is to present briefly the project called Forum & Network of System Thermal-Hydraulics Codes in Nuclear Reactor Thermal-Hydraulics (FONESYS), its participants, the motivation for the project, its main targets and working modalities. System Thermal-Hydraulics (SYS-TH) codes, also as part of the Best Estimate Plus Uncertainty (BEPU) approaches, are expected to achieve a more-and-more relevant role in nuclear reactor technology, safety and design. Namely, the number of code-users can easily be predicted to increase in the countries where nuclear technology is exploited. Thus, the idea of establishing a forum and a network among the code developers and with possible extension to code users has started to have major importance and value. In this framework the FONESYS initiative has been created. The main targets of FONESYS are: To promote the use of SYS-TH Codes and the application of the BEPU approaches. To establish acceptable and recognized procedures and thresholds for Verification and Validation (V&V). To create a common ground for discussing envisaged improvements in various areas, including user-interface, and the connection with other numerical tools, including Computational Fluid Dynamics (CFD) Codes. (C) 2014 Elsevier B.V. All rights reserved.

关键词： NUCLEAR reactors THERMAL hydraulics NUCLEAR reactors -- Safety measures COMPUTATIONAL fluid dynamics USER interfaces (Computer systems) coding theory

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Algebraic codes for network coding

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PROBLEMS OF INFORMATION TRANSMISSION 2009年第4期45卷 343-356页

作者： Gabidulin, E. M. Bossert, M. State Univ Moscow Inst Phys & Technol Moscow Russia Univ Ulm D-89069 Ulm Germany

The subspace metric is an object of active research in network coding. Nevertheless, little is known on codes over this metric. In the present paper, several classes of codes over subspace metric are defined and investigated, including codes with distance 2, codes with the maximal distance, and constant-distance constant-dimension codes. Also, Gilbert-type bounds are presented.

关键词： ALGEBRAIC functions coding theory MATHEMATICAL analysis COMPUTER network architectures DISTANCE geometry MATRICES

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APOLLO: Analysis of hexagonal critical experiments

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ANNALS OF NUCLEAR ENERGY 2009年第9期36卷 1431-1439页

作者： Hegyi, Gy. Kereszturi, A. Willermoz, G. Hungarian Acad Sci KFKI Atom Energy Res Inst H-1525 Budapest 114 Hungary CEA Cadarache F-13108 St Paul Les Durance France

Three groups of slightly enriched UO(2) fueled, hexagonal light-water moderated lattice critical experiments were analyzed with the APOLLO code at the Hungarian Academy of Sciences KFKI AEKI Reactor Analysis Laboratory, in collaboration with CEA. The work was a part of the NURESIM project where KFKI undertook to develop and qualify some calculation schemes for hexagonal problems using APOLLO2 version 2.7. in the first step non-perturbed asymptotic lattices characterized by material buckling, regular lattice perturbed by different content of gadolinium and reactivity coefficient measurements were chosen for simulation. The modeling approaches used in this analysis are discussed for selected cases. Generally the results performed by the French code using the JEF 2.2 based CEA93.V7 group library were compared to the measurements but in some cases inter-comparisons were performed to both Monte Carlo solutions as well as against results of the Hungarian lattice transport code MULTICELL based on ENDF-B/VI nuclear data. Even if the agreement between calculations and measurements differs for different codes using different nuclear data and methods the overall agreement among measured and calculated figures are good. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： coding theory REACTOR moderators LIGHT water reactors EXPERIMENTS NUCLEAR reactors SCHEMES (Algebraic geometry) MONTE Carlo method SIMULATION methods & models

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Robust blind multiuser detection based on PSO algorithm in the mismatch environment of receiver spreading codes

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COMPUTERS & ELECTRICAL ENGINEERING 2012年第6期38卷 1760-1767页

作者： Chang, Jhih-Chung Ling Tung Univ Dept Informat Technol Taichung 408 Taiwan

This paper deals with robust blind linear minimum mean square error (LMMSE) detection using the particle swarm optimization (PSO) algorithm in the presence of code mismatch. The paper shows that the PSO algorithm incorporating the linear system of the LMMSE detector, which is termed as LPSO, can significantly improve the bit error rate (BER) and the system capacity. As the code mismatch occurs, the output BER performance is vulnerable to degradation for IPSO. To remedy this problem, a blind LMMSE scheme is proposed and combined with PSO to form a robust blind IPSO (BLPSO) detector under code mismatch scenarios. Several computer simulations are provided to demonstrate the effectiveness of the proposed scheme. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： ROBUST control MULTIUSER detection (Telecommunication) PARTICLE swarm optimization ALGORITHMS coding theory LINEAR systems BIT error rate PERFORMANCE evaluation COMPUTER simulation

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Cold code decompression at runtime

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COMMUNICATIONS OF THE ACM 2003年第8期46卷 55-60页

作者： Debray, S Evans, WS Univ Arizona Tucson AZ 85721 USA Univ British Columbia Vancouver BC V5Z 1M9 Canada

We have described an approach to use execution profiles to guide codecompression. Infrequently executed code is compressed using data compression techniques that producecompact representations, and is decompressed dynamically prior to execution as needed. This hasseveral benefits: the compression technique is unhampered by the requirement that the compressedform be executable allowing improvement in the code size reduction achieved; for low executionfrequency thresholds the runtime overheads are small; and finally, no special hardware support isneeded for runtime decompression of compressed code.

关键词： COMPUTER programming COMPUTER software coding theory

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On a new class of codes for identifying vertices in graphs

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IEEE TRANSACTIONS ON INFORMATION theory 1998年第2期44卷 599-611页

作者： Karpovsky, MG Chakrabarty, K Levitin, LB Boston Univ Dept Elect & Comp Engn Reliable Comp Lab Boston MA 02215 USA

We investigate a new class of codes for the optimal covering of vertices in an undirected graph G such that any vertex in G can be uniquely identified by examining the vertices that cover it, We define a ball of radius t centered on a vertex upsilon to be the set of vertices in G that are at distance at most t from upsilon. The vertex upsilon is then said to cover itself and every other vertex in the ball with center upsilon. Our formal problem statement is as follows: Given an undirected graph G and an integer t greater than or equal to 1, find a (minimal) set C of vertices such that every vertex in G belongs to a unique set of balls of radius t centered at the vertices in C. The set of vertices thus obtained constitutes a code for vertex identification, We first develop topology-independent bounds on the size of C. We then develop methods for constructing C for several specific topologies such as binary cubes, nonbinary cubes, and trees, We also describe the identification of sets of vertices using covering codes that uniquely identify single vertices. We develop methods for constructing optimal topologies that yield identifying codes with a minimum number of codewords, Finally, we describe an application of the theory developed in this paper to fault diagnosis of multiprocessor systems.

关键词： code construction coding theory covering radius fault diagnosis graph theory multiprocessor systems

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Performance analysis of combining scheduling and space-time block coding under channel estimation error

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IET COMMUNICATIONS 2016年第4期10卷 357-362页

作者： Lee, Donghun Noh, YoungTae KATS Prod Safety Informat Div Eumseong South Korea Inha Univ Dept Comp Sci & Informat Engn Inchon South Korea

This study analyses performance-based implications of combining user scheduling and space-time block coding (STBC) (i.e. joint diversity) under channel estimation error. The exact closed-form expression of joint diversity for the achievable rate is derived. Moreover, the approximate closed-form expression of joint diversity for the outage achievable rate is derived through Gaussian approximation. The exact closed-form expression of joint diversity for the outage probability is finally derived, including the quantification of the order of diversity and the signal-to-noise ratio (SNR) gain. Using analytical results, it is demonstrated that both the achievable rate and the outage achievable rate of joint diversity improves as the number of user terminals increases through multiuser diversity. The approximate results of the analysis and simulation of the outage achievable rate for joint diversity are well matched as the number of users increases. The outage probability enhances with the number of user terminals through diversity order improvement, whereas the SNR gain is identical to that in conventional non-scheduling STBC.

关键词： Time management -- Mathematical models MATHEMATICAL models RESEARCH coding theory Product coding Channel estimation Scheduling

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Bearing Fault Diagnosis Based on Improved Locality-Constrained Linear coding and Adaptive PSO-Optimized SVM

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MATHEMATICAL PROBLEMS IN ENGINEERING 2017年第1期2017卷 1-16页

作者： Yuan, Haodong Chen, Jin Dong, Guangming Shanghai Jiao Tong Univ State Key Lab Mech Syst & Vibrat Shanghai 200240 Peoples R China

A novel bearing fault diagnosis method based on improved locality-constrained linear coding (LLC) and adaptive PSO-optimized support vector machine (SVM) is proposed. In traditional LLC, each feature is encoded by using a fixed number of bases without considering the distribution of the features and the weight of the bases. To address these problems, an improved LLC algorithm based on adaptive and weighted bases is proposed. Firstly, preliminary features are obtained by wavelet packet node energy. Then, dictionary learning with class-wise K-SVD algorithm is implemented. Subsequently, based on the learned dictionary the LLC codes can be solved using the improved LLC algorithm. Finally, SVM optimized by adaptive particle swarm optimization (PSO) is utilized to classify the discriminative LLC codes and thus bearing fault diagnosis is realized. In the dictionary leaning stage, other methods such as selecting the samples themselves as dictionary and K-means are also conducted for comparison. The experiment results show that the LLC codes can effectively extract the bearing fault characteristics and the improved LLC outperforms traditional LLC. The dictionary learned by class-wise K-SVD achieves the best performance. Additionally, adaptive PSO-optimized SVM can greatly enhance the classification accuracy comparing with SVM using default parameters and linear SVM.

关键词： SUPPORT vector machines FAULT tolerance (Engineering) coding theory PARTICLE swarm optimization ALGORITHMS

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On the homogeneous algebraic graphs of large girth and their applications

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LINEAR ALGEBRA AND ITS APPLICATIONS 2009年第7期430卷 1826-1837页

作者： Shaska, T. Ustimenko, V. Marie Curie Sklodowska Univ Inst Math Lublin Poland Univ Vlora Dept Comp Sci & Elect Engn Vlora Albania

Families of finite graphs of large girth were introduced in classical extremal graph theory. One important theoretical result here is the upper bound on the maximal size of the graph with girth >= 2d established in even circuit theorem by Erdos. We consider some results on such algebraic graphs over any field. The upper bound on the dimension of variety of edges for algebraic graphs of girth >= 2d is established. Getting the lower bound, we use the family of bipartite graphs D(n, K) with n >= 2 over a field K, whose partition sets are two copies of the vector space K-n. We consider the problem of constructing homogeneous algebraic graphs with a prescribed girth and formulate some problems motivated by classical extremal graph theory. Finally, we present a very short survey on applications of finite homogeneous algebraic graphs to coding theory and cryptography. (C) 2008 Elsevier Inc. All rights reserved.

关键词： Extremal graphs Algebraic varieties coding theory Cryptography

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A Note on a Sampling Theorem for Functions over GF(q)ⁿ Domain

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2010年第6期E93A卷 1024-1031页

作者： Ukita, Yoshifumi Saito, Tomohiko Matsushima, Toshiyasu Hirasawa, Shigeichi Yokohama Coll Commerce Dept Management Informat Yokohama Kanagawa 2308577 Japan Aoyama Gakuin Univ Coll Sci & Engn Sagamihara Kanagawa 2298558 Japan Waseda Univ Dept Appl Math Tokyo 1698555 Japan Waseda Univ Res Inst Sci & Engn Tokyo 1698555 Japan Cyber Univ Tokyo 1620853 Japan

In digital signal processing, the sampling theorem states that any real valued function f can be reconstructed from a sequence of values of f that are discretely sampled with a frequency at least twice as high as the maximum frequency of the spectrum of f. This theorem can also be applied to functions over finite domain. Then, the range of frequencies of f can be expressed in more detail by using a bounded set instead of the maximum frequency. A function whose range of frequencies is confined to a bounded set is referred to as bandlimited function. And a sampling theorem for bandlimited functions over Boolean domain has been obtained. Here, it is important to obtain a sampling theorem for bandlimited functions not only over Boolean domain (GF(2)(n) domain) but also over GF(q)(n) domain, where q is a prime power and GF(q) is Galois field of order q. For example, in experimental designs, although the model can be expressed as a linear combination of the Fourier basis functions and the levels of each factor can be represented by GF(q), the number of levels often take a value greater than two. However, the sampling theorem for bandlimited functions over GF(q)(n) domain has not been obtained. On the other hand, the sampling points are closely related to the codewords of a linear code. However, the relation between the parity check matrix of a linear code and any distinct error vectors has not been obtained, although it is necessary for understanding the meaning of the sampling theorem for bandlimited functions. En this paper, we generalize the sampling theorem for bandlimited functions over Boolean domain to a sampling theorem for bandlimited functions over GF(q)(n) domain. We also present a theorem for the relation between the parity check matrix of a linear code and any distinct error vectors. Lastly, we clarify the relation between the sampling theorem for functions over GF(q)(n) domain and linear codes.

关键词： coding theory linear codes discrete Fourier transform experimental designs

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