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A Branch-and-Bound approach for tautomer enumeration

Journal of Cheminformatics 2010年第1期2卷 1-1页

作者： Torsten Thalheim R-U Ebert R Kühne G Schüürmann UFZ Department Ecological Chemistry - Helmholtz Centre for Environmental Research Permoser Str. 15 04318 Leipzig Germany

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Research on the selection of evaluation index in service management

Research on the selection of evaluation index in service man...

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International Conference on Networking, Sensing and Control

作者： Zhu Haiping Li Zengzhi Chen Yanping Xia Hong Xi An Jiao Tong Univ Inst Comp Architecture & Networks Xian 710049 Peoples R China Xian Inst Post & Telecommun Dept Comp Sci Xian 710121 Peoples R China

ISBN: (纸本)9781424434916

In comparison with the single attribute evaluation, multi-attribute evaluation is to given an overall assessment of the effect and performance of the system by using several indexes and comprehensive evaluation function. With the number and forms of the evaluation indexes increasing, how to select the evaluation indexes is very important before evaluation. This paper mainly solved the selection and eliminating correlation of evaluation indexes, also known as index reduction. The methods of calculating the correlation degree of linear synthetic index and nonlinear synthetic index are given. Then a dynamic index reduction algorithm based on equivalence class partition is proposed. In many cases, the index reduction is occurred in an equivalence class, so the algorithm can reduce the range of index reduction. It also can make full use of the anterior reduction results to increase the efficiency of algorithm. The simulations experiments show that the more indexes, the more efficient this algorithm can be.

关键词： Evaluation Indexes Equivalence classes algorithm efficiency Indexes

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Effects of Suffix Repetition Rates of a String on the Performance of String Matching algorithms

Effects of Suffix Repetition Rates of a String on the Perfor...

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8th IEEE/ACIS International Conference on Computer and Information Science

作者： Wang, Yang Missouri State Univ Dept Comp Sci Springfield MO 65897 USA

ISBN: (纸本)9780769536415

The highly efficient Boyer-Moore's string matching algorithm utilizes information on multi-occurrences of string suffixes in a pattern string to avoid backtracks in searching the pattern string. One hypothesis is that Boyer-Moore's algorithm even benefits more from highly self-repetitive patterns. In this paper, the author studies how multi-occurrences of string suffixes affect the performance of the Boyer-Moore's algorithm as well as some other well known string search algorithms. The paper introduces a new concept of suffix repetition rate (SPR) to measure how frequently the suffixes of a string occur inside of the string. Using this measurement, experiments with several thousands patterns over the entire range of SRRs have been carried out, and the results show that increasing of SRR on pattern strings does not improve the performance of a searching algorithm in terms of efficiency.

关键词： String matching string suffix suffix repetition rates algorithm efficiency

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A universally fastest algorithm for Max 2-Sat, Max 2-CSP, and everything in between 09

A universally fastest algorithm for Max 2-Sat, Max 2-CSP, an...

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Annual ACM-Society for Industrial and Applied Mathmatics Symposium on Discrete algorithms

作者： Serge Gaspers Gregory B. Sorkin Department of Informatics University of Bergen Department of Mathematical Sciences IBM T.J. Watson Research Center

We introduce "hybrid" Max 2-CSP formulas consisting of "simple clauses", namely conjunctions and disjunctions of pairs of variables, and general 2-variable clauses, which can be any integer-valued functions of pairs of boolean variables. This allows an algorithm to use both efficient reductions specific to AND and OR clauses, and other powerful reductions that require the general CSP setting. Parametrizing an instance by the fraction p of non- simple clauses, we give an exact (exponential-time) algorithm that is the fastest polynomial-space algorithm known for Max 2-Sat (and other p = 0 formulas, with arbitrary mixtures of AND and OR clauses); the only efficient algorithm for mixtures of AND, OR, and general integer-valued clauses; and tied for fastest for general Max 2-CSP (p = 1). Since a pure 2-Sat input instance may be transformed to a general CSP instance in the course of being solved, the algorithm's efficiency and generality go hand in hand. Our novel analysis results in a family of running- time bounds, each optimized for a particular value of p. The algorithm uses new reductions introduced here, as well as recent reductions such as "clause-learning" and "2-reductions" adapted to our setting's mixture of simple and general clauses. Each reduction imposes constraints on various parameters, and the running-time bound is an "objective function" of these parameters and p. The optimal running-time bound is obtained by solving a convex nonlinear program, which can be done efficiently and with a certificate of optimality.

关键词： defibrotide algorithms algorithm efficiency Hand Operations Research Gold Licence chip scale packaging communicating sequential processes Bound phosphocellulose mixtures optimality Andromeda formula

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The Briefest Reduct of Rough Sets Based On Genetic algorithm

The Briefest Reduct of Rough Sets Based On Genetic Algorithm

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IEEE International Symposium on IT in Medicine and Education

作者： Guan Hong-bo Yang Bao-an Donghua Univ Glorious Sun Sch Business & Management Shanghai 200051 Peoples R China

ISBN: (纸本)9781424425105

This paper focuses on the discussion about the briefest reduct of Rough Sets which is extracted by genetic algorithm. The fitting function is designed by the combination of the relying degree of RS and sum of seeds which is the attributes of data Genetic algorithm operator is applied and the algorithm is tested by UCI database. After the analysis and discussion, RGA and RGA_2 have been proved available. In the discussion, crossover and mutation probability have got a experienced number. Increasing the sum of seeds, and saving the last generation optimized seeds can be improving the efficiency of algorithm

关键词： Rough sets Genetic algorithm (GA) algorithm efficiency symmetric self-electro-optic effect devices Debates sums

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Decoupled estimation of 2D DOA for coherently distributed sources using 3D matrix pencil method

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2008年第unknown期2008卷 417157-1-417157-7-0页

作者： Zhang Gaoyi Tang Bin Univ Elect Sci & Technol China Sch Elect Engn Chengdu 610054 Peoples R China

A new 2D DOA estimation method for coherently distributed (CD) source is proposed. CD sources model is constructed by using Taylor approximation to the generalized steering vector (GSV), whereas the angular and angular spread are separated from signal pattern. The angular information is in the phase part of the GSV, and the angular spread information is in the module part of the GSV, thus enabling to decouple the estimation of 2D DOA from that of the angular spread. The array received data is used to construct three-dimensional (3D) enhanced data matrix. The 2D DOA for coherently distributed sources could be estimated from the enhanced matrix by using 3D matrix pencil method. Computer simulation validated the efficiency of the algorithm. Copyright (C) 2008 Z. Gaoyi and T. Bin.

关键词： Distribute pencil DECOUPLING Angle algorithm efficiency United States Department of Agriculture angular spread angular information Three Dimensions

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Simulation of miscible flow including bypassed oil and dispersion control

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SPE RESERVOIR EVALUATION & ENGINEERING 2007年第5期10卷 500-507页

作者： Coats, K. H. Thomas, L. K. Pierson, R. G. Coats Engineering ConocoPhillips (retired)

This paper describes methods for the simulation of first-contact miscible (FCM), multicontact miscible, and vaporizing gas drive, which include logic to account for bypassed oil. Dispersion control is included for FCM cases. First-contact miscibility may be simulated in fully compositional mode with any number of components, N-c, or in two-pseudocomponent equation-of-state (EOS) mode. Pseudoization is performed internally in the model so that hydrocarbon-fluid density and viscosity, as functions of pressure and composition, are the same as calculated in N-c-component mode. Bypassed oil and dispersion control are based on an extension of Koval's (1963) method. This procedure allows the user to adjust the fractional flow of oil during upscaling or history matching to match fine-grid or historical results. This feature can be used to simulate both water-alternating-gas (WAG) and tertiary-recovery projects where solvent injection is preceded by a water-injection period. Example cases are included to illustrate the techniques presented in this paper. Results are also given on the efficiencies of the algorithms.

关键词： GAS DRIVE simulating algorithm efficiency oils Formal logic SOLVENT INJECTION

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Linearized Zverev Transform and its application for modeling radio occultations

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RADIO SCIENCE 2007年第3期42卷 RS3023.1-RS3023.9页

作者： Gorbunov, M. E. Lauritsen, K. B. RAS Oboukhov Inst Atmospher Phys Moscow 119017 Russia Danish Metrol Inst DK-2100 Copenhagen Denmark

The multiple phase screens technique is often used for modeling wave propagation and radio occultation sounding of the atmosphere. The last step of this procedure is the propagation from the last phase screen to the observation orbit of the spaceborne receiver. This step was formerly performed by the computation of multiple diffractive integrals, which impairs the numerical efficiency of the algorithm. We introduce an asymptotic method of wave propagation in vacuum from the last phase screen to a generic observation path. The exact solution is written in the form of the Zverev Transform, which belongs to the class of Fourier Integral Operators (FIO). The phase function of such an operator can be derived from the geometric optical equations. We construct an approximation for the Zverev Transform, utilizing the linearization of the equation of the geometric optical ray propagation in the vicinity of a smooth model of the ray structure. This permits the design of a fast numerical algorithm based on an FFT. Numerical simulations are performed for microwave propagation through a model atmosphere based on realistic gridded global fields of meteorological parameters. The new method based on the Linearized Zverev Transform is compared with the standard combination of multiple phase screens and diffractive integrals and with the asymptotic forward modeling for the propagation of centimeter waves in the atmosphere on limb paths. This method is especially useful for modeling LEO-LEO microwave occultations at frequencies of 9-30 GHz. The simulations demonstrate a high accuracy and numerical efficiency of the proposed method.

关键词： atmosphere Linearization MULTI-PHASE phase function OCCULTATIONS Transform microwave propagation algorithm efficiency Modeling

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A heuristic tree algorithm with a revocation based GA for test pattern generation of VLSI circuits

A heuristic tree algorithm with a revocation based GA for te...

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International Conference on Electrical Engineering

作者： Rad, M. A. Eshgh, S. M. Shahid Beheshti Univ Med Sci Tehran Iran

ISBN: (纸本)9781424408924

Increasing complexity of VISI circuits has led to a progressive need for an efficient test generation method that ensures a fault-free performance of the Circuit-Under-Test. The revocation based genetic algorithm which we suggested before had resulted in higher fault coverage and shorter computational time in comparison with previous test pattern generation systems. In this paper we suggest a new heuristic tree algorithm for test pattern generation which works in combination with the revocation based genetic method. Simulations done on IS CAS'85 benchmarks confirm the efficiency of the algorithm and its significant promotion in comparison with the GAs and other previous test pattern generation methods.

关键词： Test pattern generation Very large scale integration fault coverage computational time algorithm efficiency algorithms Test generation Heuristics

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PROBLEMS OF DISCRETE OPTIMIZATION: CHALLENGES AND MAIN APPROACHES TO SOLVE THEM

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CYBERNETICS AND SYSTEMS ANALYSIS 2006年第4期42卷 465-482页

作者： Sergienko, I. V. Shylo, V. P. Natl Acad Sci Ukraine VM Glushkov Inst Cybernet Kiev Ukraine

This paper briefly reviews the current state of the art in the field of discrete optimization problems. Emphasis is on the generalization of the experience gained at the V. M. Glushkov Institute of Cybernetics of the National Academy of Sciences of Ukraine in research and development of solution methods and software for various classes of complicated discrete programming problems.

关键词： discrete optimization decrease-vector method method of global equilibrium search metaheuristics computational experiment algorithm efficiency

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