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OPTIMIZATION OF TURBULENCE MODELS BY MEANS OF A LOGICAL search algorithm

APPLIED SCIENTIFIC REsearch 1973年第5期27卷 321-334页

作者： HUFFMAN, GD JONES, CD BRODKEY, RS OHIO STATE UNIV DEPT MECH ENGNCOLUMBUSOH 43210 OHIO STATE UNIV DEPT CHEM ENGNCOLUMBUSOH 43210 IMPERIAL COLL LONDONENGLAND

The momentum and turbulent kinetic energy equations are solved for a number of phenomenological closure approximations. The various methods are evaluated by comparison with several selected sets of experimental data. The empirical constants are determined such that the deviation between the experimental and theoretical values is minimized. The minimization process is carried out via a logical search algorithm which can also be applied to other problems in which the minimum or maximum value of a function of several variables is desired.

关键词： Experimental Data Kinetic Energy search algorithm Turbulent Kinetic Energy Turbulence Model

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T*: a weighted double-heuristic search algorithm to find the shortest path

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INTERNATIONAL JOURNAL OF COMPUTING SCIENCE AND MATHEMATICS 2019年第1期10卷 58-70页

作者： Gharajeh, Mohammad Samadi Islamic Azad Univ Tabriz Branch Young Researchers & Elite Club Tabriz Iran

This paper proposes a weighted double-heuristic search algorithm to find the shortest path between two points. It can be used in numerous fields such as graph theory, game theory, and network. This algorithm, called T*, uses a weighted and heuristic function as f(x) = alpha x t(x) + beta x hl(x) + gamma x h2(x). It selects the path which minimises f(x) where x is a current node on the path, t(x) is cost of the path from start to x, h1(x) is a heuristic to estimate the cost from x to the straight line passing through start and target, and h2(x) is a heuristic to estimate cost of the cheapest path from x to target. Furthermore, alpha, beta and gamma indicate effective weights of each sub-function on f(x). T* algorithm is compared to the Greedy and A* algorithms in terms of hit rate and the number of processed nodes. Comparison results show that the proposed algorithm has a high efficiency compared to other algorithms.

关键词： shortest path search algorithm weighted strategy double-heuristic function graph theory

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CONFORMATIONAL BACKBONE DYNAMICS OF THE CYCLIC DECAPEPTIDE ANTAMANIDE - APPLICATION OF A NEW MULTICONFORMATIONAL search algorithm-BASED ON NMR DATA

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BIOCHEMISTRY 1993年第41期32卷 10960-10974页

作者： BLACKLEDGE, MJ BRUSCHWEILER, R GRIESINGER, C SCHMIDT, JM XU, P ERNST, RR SWISS FED INST TECHNOL PHYS CHEM LABCH-8092 ZURICHSWITZERLAND

A general procedure for the analysis of biomolecular structures by NMR in the presence of rapid conformational dynamics has been applied to the study of the cyclic decapeptide antamanide. Two-dimensional experiments, relaxation measurements in the rotating frame, and homo- and heteronuclear coupling constant determinations have been used to characterize the dynamic properties of the molecule, in combination with a novel search algorithm for investigating multiconformational equilibria. Direct evidence for the presence of a conformational exchange process with an activation energy of approximately 20 kJ mol-1 and an exchange lifetime of approximately 25 mus at 320 K has been obtained from rotating frame relaxation measurements. This evidence is combined with the information derived from the multiconformational search algorithm MEDUSA to propose sets of structures that coexist in a dynamic exchange equilibrium.

关键词： .NMR Data restrained dihedral search algorithm Medusa internuclear Wiithrich rotating frame conformational exchange Heteronuclear coupling cross-relaxation Antamanide Conformational Backbone dynamic exchange

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Box length search algorithm for molecular simulation of systems containing periodic structures

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JOURNAL OF CHEMICAL PHYSICS 2004年第4期120卷 2049-2055页

作者： Schultz, AJ Hall, CK Genzer, J N Carolina State Univ Dept Chem Engn Raleigh NC 27695 USA

We have developed a box length search algorithm to efficiently find the appropriate box dimensions for constant-volume molecular simulation of periodic structures. The algorithm works by finding the box lengths that equalize the pressure in each direction while maintaining constant total volume. Maintaining the volume at a fixed value ensures that quantitative comparisons can be made between simulation and experimental, theoretical or other simulation results for systems that are incompressible or nearly incompressible. We test the algorithm on a system of phase-separated block copolymers that has a preferred box length in one dimension. We also describe and test a Monte Carlo algorithm that allows the box lengths to change while maintaining constant volume. We find that the box length search algorithm converges at least two orders of magnitude more quickly than the variable box length Monte Carlo method. Although the box length search algorithm is not ergodic, it successfully finds the box length that minimizes the free energy of the system. We verify this by examining the free energy as determined by the Monte Carlo simulation. (C) 2004 American Institute of Physics.

关键词： .Periodic Structures search algorithm constant volume systems containing total volume converges box lengths box length Monte

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Improved gravitational search algorithm for unit commitment considering uncertainty of wind power

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ENERGY 2014年 67卷 52-62页

作者： Ji, Bin Yuan, Xiaohui Chen, Zhihuan Tian, Hao Huazhong Univ Sci & Technol Sch Hydropower & Informat Engn Wuhan 430074 Peoples R China

With increasing wind farm integrations, unit commitment (UC) is more difficult to solve because of the intermittent and fluctuation nature of wind power. In this paper, scenario generation and reduction technique is applied to simulate the impacts of its uncertainty on system operation. And then a model of thermal UC problem with wind power integration (UCW) is established. Combination of quantuminspired binary gravitational search algorithm (GSA) and scenario analysis method is proposed to solve UCW problem. Meanwhile, heuristic search strategies are used to handle the constraints of thermal unit for each scenario. In addition, a priority list of thermal units based on the weight between average full-load cost and maximal power output is utilized during the optimization process. Moreover, two UC test systems with and without wind power integration are used to verify the feasibility and effectiveness of the proposed method as well as the performance of the algorithm. The results are analyzed in detail, which demonstrate the model and the proposed method is practicable. The comparison with other methods clearly shows that the proposed method has higher efficiency for solving UC problems with and even without wind farm integration. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Wind power Unit Commitment Scenario analysis Quantum-inspired binary gravitational search algorithm Heuristic strategy

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The design of a peptide sequence to inhibit HIV replication: a search algorithm combining Monte Carlo and self-consistent mean field techniques

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JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS 2014年第10期32卷 1523-1536页

作者： Xiao, Xingqing Hall, Carol K. Agris, Paul F. N Carolina State Univ Chem & Biomol Engn Dept Raleigh NC 27695 USA SUNY Albany RNA Inst Albany NY 12222 USA

We developed a search algorithm combining Monte Carlo (MC) and self-consistent mean field techniques to evolve a peptide sequence that has good binding capability to the anticodon stem and loop (ASL) of human lysine tRNA species, tRNA(Lys3), with the ultimate purpose of breaking the replication cycle of human immunodeficiency virus-1. The starting point is the 15-amino-acid sequence, RVTHHAFLGAHRTVG, found experimentally by Agris and co-workers to bind selectively to hypermodified tRNA(Lys3). The peptide backbone conformation is determined via atomistic simulation of the peptide-ASL(Lys3) complex and then held fixed throughout the search. The proportion of amino acids of various types (hydrophobic, polar, charged, etc.) is varied to mimic different peptide hydration properties. Three different sets of hydration properties were examined in the search algorithm to see how this affects evolution to the best-binding peptide sequences. Certain amino acids are commonly found at fixed sites for all three hydration states, some necessary for binding affinity and some necessary for binding specificity. Analysis of the binding structure and the various contributions to the binding energy shows that: 1) two hydrophilic residues (asparagine at site 11 and the cysteine at site 12) "recognize" the ASL(Lys3) due to the VDW energy, and thereby contribute to its binding specificity and 2) the positively charged arginines at sites 4 and 13 preferentially attract the negatively charged sugar rings and the phosphate linkages, and thereby contribute to the binding affinity.

关键词： protein design Monte Carlo technique self-consistent mean field theory search algorithm binding affinity and specificity

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A dichotomic search algorithm for mining and learning in domain-specific logics

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FUNDAMENTA INFORMATICAE 2005年第1-2期66卷 1-32页

作者： Ferré, S King, RD Univ Rennes 1 IRISA F-35042 Rennes France Univ Wales Dept Comp Sci Aberystwyth SY23 3DB Dyfed Wales

Many application domains make use of specific data structures such as sequences and graphs to represent knowledge. These data structures are ill-fitted to the standard representations used in machine learning and data-mining algorithms: propositional representations are not expressive enough, and first order ones are not efficient enough. In order to efficiently represent and reason on these data structures, and the complex patterns that are related to them, we use domain-specific logics. We show these logics can be built by the composition of logical components that model elementary data structures. The standard strategies of top-down and bottom-up search are ill-suited to some of these logics, and lack flexibility. We therefore introduce a dichotomic search strategy, that is analogous to a dichotomic search in an ordered array. We prove this provides more flexibility in the search, while retaining completeness and non-redundancy. We present a novel algorithm for learning using domain specific logics and dichotomic search, and analyse its complexity. We also describe two applications which illustrates the search for motifs in sequences;where these motifs have arbitrary length and length-constrained gaps. In the first application sequences represent the trains of the East-West challenge;in the second application they represent the secondary structure of Yeast proteins for the discrimination of their biological functions.

关键词： data structures domain-specific logics search algorithm dichotomy formal concept analysis concept learning pattern mining bioinformatics

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A hybrid, self-adjusting search algorithm for optimal space trajectory design

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ADVANCES IN SPACE REsearch 2012年第4期50卷 471-488页

作者： Bolle, Andrea Circi, Christian Univ Roma La Sapienza Dept Astronaut Elect & Energet Engn I-00138 Rome Italy Univ Roma La Sapienza CRPSM I-00138 Rome Italy

The aim of the present paper is to propose a hybrid, self adjusting, search algorithm for space trajectory optimization. By taking advantage of both direct and indirect methods, the present algorithm allows the finding of the optimal solution through the introduction of some new control parameters, whose number is smaller than that of the Lagrange multipliers, and whose range is bounded. Eventually, the optimal solution is determined by means of an iterative self-adjustment of the search domain occurring at "runtime", without any correction by an external user. This new set of parameters can be found through a reduction process of the degrees of freedom, obtained through the transversality conditions before entering the search loop. Furthermore, such a process shows that Lagrange multipliers are subject to a deep symmetry mirroring the features of the state vector. The algorithm reliability and efficiency is assessed through some test cases, and by reproducing some optimal transfer trajectories: a full three-dimensional, minimum time Mars mission, an optimal transfer to Jupiter, and finally an injection into a circular Moon orbit. (C) 2012 COSPAR. Published by Elsevier Ltd. All rights reserved.

关键词： Interplanetary transfer search algorithm Optimal trajectory Direct and indirect methods Lagrange multipliers

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A Coordinated search algorithm for a Lost Target on the Plane

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Computer Systems Science & Engineering 2022年第1期40卷 127-137页

作者： Sundus Naji Al-Aziz Abd Al-Aziz Hosni El-Bagoury W.Afifi Department of Mathematics College of SciencePrincess Nourah bint Abdulrahman UniversityRiyadhSaudi Arabia Department of Mathematics Faculty of ScienceTanta UniversityTantaEgypt Department of Mathematics and Statistics College of ScienceTaibah UniversityYanbuSaudi Arabia

Concepts in search theory have developed since World War *** study of search plans has found considerable interest among searchers due to its wide applications in our *** for lost targets either located or moved is often a time-critical issue,especially when the target is very *** many commercial and scientific missions at sea,it is of crucial importance to find lost targets *** illustrate a technique known as coordinated search,that completely characterizes the search for a randomly located target on a *** idea is to avoid wasting time looking for a missing *** searchers or robots start from the center of a circle to search out a lost target,the first searcher looks for the target on the right side of the circular area,and the second one looks for it on the left *** time taken to detect the target is obtained by assuming the target’s position has a symmetric *** procedures to facilitate the detection of the target are presented as an algorithm and as a *** application demonstrates the applicability of this search technique and the associated decrease in search *** effectiveness is illustrated by numerical results,which indicates considerable promise.

关键词： Expected value sensors lost target coordinated search search algorithm lost ship

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A spectral clustering search algorithm for predicting shallow landslide size and location

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JOURNAL OF GEOPHYSICAL REsearch-EARTH SURFACE 2015年第2期120卷 300-324页

作者： Bellugi, Dino Milledge, David G. Dietrich, William E. McKean, Jim A. Perron, J. Taylor Sudderth, Erik B. Kazian, Brian MIT Dept Earth Atmospher & Planetary Sci Cambridge MA 02139 USA Univ Durham Dept Geog Durham England Univ Calif Berkeley Dept Earth & Planetary Sci Berkeley CA 94720 USA US Forest Serv USDA Rocky Mt Res Stn Boise ID USA Brown Univ Dept Comp Sci Providence RI 02912 USA Palantir Technol Palo Alto CA USA

The potential hazard and geomorphic significance of shallow landslides depend on their location and size. Commonly applied one-dimensional stability models do not include lateral resistances and cannot predict landslide size. Multidimensional models must be applied to specific geometries, which are not known a priori, and testing all possible geometries is computationally prohibitive. We present an efficient deterministic search algorithm based on spectral graph theory and couple it with a multidimensional stability model to predict discrete landslides in applications at scales broader than a single hillslope using gridded spatial data. The algorithm is general, assuming only that instability results when driving forces acting on a cluster of cells exceed the resisting forces on its margins and that clusters behave as rigid blocks with a failure plane at the soil-bedrock interface. This algorithm recovers predefined clusters of unstable cells of varying shape and size on a synthetic landscape, predicts the size, location, and shape of an observed shallow landslide using field-measured physical parameters, and is robust to modest changes in input parameters. The search algorithm identifies patches of potential instability within large areas of stable landscape. Within these patches will be many different combinations of cells with a Factor of Safety less than one, suggesting that subtle variations in local conditions (e.g., pore pressure and root strength) may determine the ultimate form and exact location at a specific site. Nonetheless, the tests presented here suggest that the search algorithm enables the prediction of shallow landslide size as well as location across landscapes.

关键词： shallow landslides landslide size hillslope geomorphology spectral clustering search algorithm computational modeling

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