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18th International Offshore and Polar Engineering Conference (ISOPE 2008)

作者： Osawa, Naoki Hashimoto, Kiyoshi Sawamura, Junji Tanaka, Hironori Osaka Univ Dept Naval Architecture & Ocean Engn Osaka Japan

ISBN: (纸本)9781880653708

The temperature of the gas adjacent to the plate T-G and local heat transfer coefficient alpha can be considered to remain nearly unchanged with time during spot and line heating. A generic algorithms (GA)-based direct identification technique for T-G and alpha is proposed. T-G and a during a spot heating test is identified by the proposed technique, and TG for this spot heating test is measured by laser induced fluorescence technique. The validity of the proposed GA-based technique is investigated by comparing the identified and measured T-G, and comparing the measured T-B and that calculated by giving the identified T-G and a as thermal boundary conditions. As results, the followings are found. 1) Distributions of T-G and alpha during a spot heating test can be directly identified by proposed GA-based technique. The identified TG is close to the one measured by a LIF system. 2) The plate back surface temperature during the spot heating test calculated from the identified TG and cc is comparable to the one measured. The results obtained demonstrate the accuracy of the identified heat input parameters and the validity of the proposed GA-based identification technique. 3) The proposed GA-based identification technique is valid for the high power heating case for which the conventional IHC-based techniques are not applicable.

关键词： generic algorithms Heat flux Heat transfer Inverse beat conduction analysis Laser induced fluorescence technique Temperature estimation Line heating

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Black-box extension fields and the inexistence of field-homomorphic one-way permutations

Black-box extension fields and the inexistence of field-homo...

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13th International Conference on Theory and Application of Cryptology and Information Security

作者： Maurer, Ueli Raub, Dominik ETH Dept Comp Sci CH-8092 Zurich Switzerland

ISBN: (纸本)9783540768999

The black-box field (BBF) extraction problem is, for a given field F, to determine a secret field element hidden in a black-box which allows to add and multiply values in IF in the box and which reports only equalities of elements in the box. This problem is of cryptographic interest for two reasons. First, for F = F-p it corresponds to the generic reduction of the discrete logarithm problem to the computational Diffie-Hellman problem in a group of prime order p. Second, an efficient solution to the BBF extraction problem proves the inexistence of field-homomorphic one-way permutations whose realization is an interesting open problem in algebra-based cryptography. BBFs are also of independent interest in computational algebra. In the previous literature BBFs had only been considered for the prime field case. In this paper we consider a generalization of the extraction problem to BBFs that are extension fields. More precisely we discuss the representation problem defined as follows: For given generators g(1), ... ,g(d) algebraically generating a BBF and an additional element x, all hidden in a black-box, express x algebraically in terms of g(1), ... ,g(d). We give an efficient algorithm for this representation problem and related problems for fields with small characteristic (e.g. F = F-2n for some n). We also consider extension fields of large characteristic and show how to reduce the representation problem to the extraction problem for the underlying prime field. These result's imply the inexistence of field-homornorphic (as opposed to only group-homomorphic, like RSA) one-way permutations for fields of small characteristic.

关键词： black-box fields generic algorithms homomorphic encryption one-way permutations computational algebra

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Evolution and development of a multicellular organism: Scalability, resilience, and neutral complexification

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ARTIFICIAL LIFE 2006年第3期12卷 381-409页

作者： Federici, Diego Downing, Keith Norwegian Univ Sci & Technol Dept Comp & Informat Sci N-7491 Trondheim Norway

To increase the evolvability of larger search spaces, several indirect encoding strategies have been proposed. Among these, multicellular developmental systems are believed to offer great potential for the evolution of general, scalable, and self-repairing organisms. We reinforce this view, presenting the results achieved by such a model and comparing it against direct encoding. Extra effort has been made to make this comparison both general and meaningful. Embryonal stages, a generic method showing increased evolvability and applicable to any developmental model, are introduced. Development with embryonal stages implements what we refer to as direct neutral complexification: direct genotype complexification by neutral duplication of expressed genes. The results show that, even for high-complexity evolutionary targets, the developmental model proves more scalable. The model also shows emergent self-repair, which is used to produce highly resilient organisms.

关键词： generic algorithms development scalability fault tolerance neutral complexification

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SPARE Parts: a C++ toolkit for string pattern recognition

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SOFTWARE-PRACTICE & EXPERIENCE 2004年第7期34卷 697-710页

作者： Watson, BW Cleophas, L Univ Pretoria Dept Comp Sci ZA-0002 Pretoria South Africa Eindhoven Univ Technol Dept Math & Comp Sci NL-5600 MB Eindhoven Netherlands

In this paper, we consider the design and implementation of SPARE Parts, a C++ toolkit for pattern matching. SPARE Parts (in particular, the 2003 version presented in this article) is the second generation string pattern matching toolkit by the authors. The toolkit, the first generic program for keyword pattern matching, contains implementations of the well-known Knuth-Morris-Pratt, Boyer-Moore, Aho-Corasick and Commentz-Walter algorithms (and their variants). The toolkit is freely available for non-commercial use. Copyright (C) 2004 John Wiley Sons, Ltd.

关键词： keyword pattern matching C plus plus toolkits C plus plus frameworks generic algorithms foundation classes taxonomies

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A comparative study of global optimization approaches to MEG source localization

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INTERNATIONAL JOURNAL OF COMPUTER MATHEMATICS 2003年第3期80卷 305-324页

作者： Jiang, TZ Luo, A Li, XD Kruggel, F Chinese Acad Sci Inst automat Natl Lab Pattern Recognit Beijing 100080 Peoples R China Max Planck Inst Cognit Neurosci D-04103 Leipzig Germany

It is well-known that the problem of MEG source localization can be cast as an optimization problem. So far, there have been many works in which various optimization methods were adopted for source localization. In this paper, we compare the performance of three typical and widely used optimization techniques for a specific MEG source localization problem. We first introduce a hybrid algorithm by combining genetic and local search strategies to overcome disadvantages of conventional genetic algorithms. Second, we apply the tabu search, a widely used optimization method in combinational optimization and discrete mathematics, to source localization. To the best of our knowledge, this is the first attempt in the literature to apply tabu search to MEG/EEG source localization. Third, in order to further compare the performance of the above algorithms, simulated annealing is also applied to MEG source localization problem. The computer simulation results show that our local genetic algorithm is the most effective approach to dipole localization, and the tabu search method is also a very good strategy for this problem.

关键词： magnetoencephalogram (MEG) dipoles global optimization generic algorithms simulated annealing tabu search

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Deterministic versus nondeterministic time and lower bound problems

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JOURNAL OF THE ACM 2003年第1期50卷 91-95页

作者： Stearns, RE SUNY Albany Dept Comp Sci Albany NY 12222 USA

Because many problems of general interest have natural nondeterministicalgorithms and because computers act deterministically, it is important to understand therelationship between deterministic and nondeterministic time. Specifically, it is important tounderstand how quickly a deterministic computing device can determine the outcome of anondeterministic calculation. So far, we have no general techniques that work any better than tryingall step-by-step simulations, an exponential method. The most famous question concerningdeterminism versus nondeterminism is the P = NP question. However, this is a different question than"what is the relationship?" and it is possible that significant progress about the relationship canbe achieved without answering the P = NP question. Thanks to efficient reductions from Turingmachine simulation to SAT, the relationship question can be posed as a question about SAT. Theproblem of proving a nontrivial lower bound on the time required to solve SAT is just an instance ofthe larger problem of proving lower bounds for any natural problem. It is suggested that a study ofgeneric problems might be a fruitful approach toward insights on such problems.

关键词： theory algorithms computational complexity generic algorithms generic problems nondeterminism NP-completeness power index SAT time complexity

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Designing mathematical libraries based on requirements for theorems

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ANNALS OF MATHEMATICS AND ARTIFICIAL INTELLIGENCE 2003年第1-3期38卷 193-209页

作者： Schwarzweller, C Univ Tubingen Wilhelm Schickard Inst Comp Sci D-72076 Tubingen Germany

Theorems can be considered independent of abstract domains;a theorem rather depends on a set of properties necessary to prove the theorem correct. Following this observation theorems can be formulated and proven more generally thereby improving reuse of mathematical theorems. We discuss how this view influences the design of mathematical libraries and illustrate our approach with examples written in the Mizar language. We also argue that this approach allows for both stating requirements of generic algorithms and checking whether particular instantiations of generic algorithms are semantically correct.

关键词： mechanized reasoning reuse of theorems requirements for theorems mathematical libraries the Mizar system generic algorithms

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Exploiting structure in quantified formulas

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JOURNAL OF algorithms-COGNITION INFORMATICS AND LOGIC 2002年第2期43卷 220-263页

作者： Stearns, RE Hunt, HB SUNY Albany Dept Comp Sci Albany NY 12222 USA

We study the computational problem "find the value of the quantified formula obtained by quantifying the variables in a sum of terms." The "sum" can be based on any commutative monoid, the "quantifiers" need only satisfy two simple conditions. and the variables can have any finite domain. This problem is a generalization of the problem "given a sum-of-products of terms, find the value of the sum" studied in [R.E. Stearns and H.B. Hunt III, SIAM J. Comput. 25 (1996) 448-476]. A data structure called a,,structure tree" is defined which displays information about "subproblems" that can be solved independently during the process of evaluating the formula. Some formulas have "good" structure trees which enable certain generic algorithms to evaluate the formulas in significantly less time than by brute force evaluation. By "generic allgorithm," we mean an algorithm constructed from uninterpreted function symbols, quantifier symbols, and monoid operations. The algebraic nature of the model facilitates a formal treatment of "local reductions" based on the "local replacement" of terms. Such local reductions "preserve formula structure" in the sense that structure trees with nice properties transform into structure trees with similar properties. These local reductions can also be used to transform hierarchical specified problems with useful structure into hierarchically specified problems having similar structure. (C) 2002 Elsevier Science (USA). All rights reserved.

关键词： quantified formulas generic algorithms satisfiability problems constraint satisfaction problems non-serial dynamic programming computational complexity channelwidth structure trees treewidth tree decompositions

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generic algorithms for solving ODE using the Tau method with an error estimation

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INTERNATIONAL JOURNAL OF COMPUTER MATHEMATICS 1999年第1期72卷 63-80页

作者： Adeniyi, RB Olugbara, OO Taiwo, OA Univ Ilorin Dept Math Comp Sci Ilorin Nigeria

The Tau method is an accurate and efficient method for the numerical solution of ordinary differential equation (O.D.E) with polynomial coefficients. In [1] Adeniyi et al., we derived a recursive formula for a fast reliable computational error estimate of Tau method. In the present work, we present the generic algorithms for solving O.D.E. using the Tau method. The pseudocodes describing the algorithms are in C-like language. The algorithms are assembled into a reusable Tau objects' Class Hierarchy (TOCH) with specification given in the interface definition language (IDL) representation and implemented using the C+ + Programming language.

关键词： polynomial coefficients generic algorithms Tau method Tau object class hierarchy interface definition language

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Small generic hardcore subsets for the discrete logarithm: Short secret DL-keys

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INFORMATION PROCESSING LETTERS 2001年第2期79卷 93-98页

作者： Schnorr, CP Univ Frankfurt Fachbereich Math Informat D-60439 Frankfurt Germany Bell Labs Murray Hill NJ 07974 USA

Let G be a group of prime order q with generator g. We study hardcore subsets H subset of G of the discrete logarithm (DL) log(g) in the model of generic algorithms. In this model we count group operations such as multiplication and division, while computations with non-group data are for free. It is known from Nechaev [Math. Notes 55 (1994) 165] and Shoup [Lecture Notes in Comp. Sci., Vol. 1233, Springer, Berlin, 1997, p. 256] that generic DL-algorithms for the entire group G must perform root 2q generic steps. We show that DL-algorithms for small subsets H subset of G require 1/2m + o(m) generic steps for almost all H of size #H = m with m less than or equal to rootq. Conversely, 1/2m + 1 generic steps are sufficient for all H subset of G of even size m. Our main result justifies to generate secret DL-keys from seeds that are only 1/2 log(2) q bits long. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： computational complexity cryptography discrete logarithm (DL) generic algorithms generic complexity hardcore subsets

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