• Title/Summary/Keyword: Search Space Reduction

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Search Space Reduction Techniques in Small Molecular Docking (소분자 도킹에서 탐색공간의 축소 방법)

  • Cho, Seung Joo
    • Journal of Integrative Natural Science
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    • v.3 no.3
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    • pp.143-147
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    • 2010
  • Since it is of great importance to know how a ligand binds to a receptor, there have been a lot of efforts to improve the quality of prediction of docking poses. Earlier efforts were focused on improving search algorithm and scoring function in a docking program resulting in a partial improvement with a lot of variations. Although these are basically very important and essential, more tangible improvements came from the reduction of search space. In a normal docking study, the approximate active site is assumed to be known. After defining active site, scoring functions and search algorithms are used to locate the expected binding pose within this search space. A good search algorithm will sample wisely toward the correct binding pose. By careful study of receptor structure, it was possible to prioritize sub-space in the active site using "receptor-based pharmacophores" or "hot spots". In a sense, these techniques reduce the search space from the beginning. Further improvements were made when the bound ligand structure is available, i.e., the searching could be directed by molecular similarity using ligand information. This could be very helpful to increase the accuracy of binding pose. In addition, if the biological activity data is available, docking program could be improved to the level of being useful in affinity prediction for a series of congeneric ligands. Since the number of co-crystal structures is increasing in protein databank, "Ligand-Guided Docking" to reduce the search space would be more important to improve the accuracy of docking pose prediction and the efficiency of virtual screening. Further improvements in this area would be useful to produce more reliable docking programs.

An Efficient Algorithm for finding Optimal Spans to determine R=1/2 Rate Systematic Convolutional Self-Doubly Orthogonal Codes (R=1/2 Self-Doubly 조직 직교 길쌈부호를 찾는 효율적인 최적 스팬 알고리듬)

  • Doniyor, Atabaev;Suh, Hee-Jong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.11
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    • pp.1239-1244
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    • 2015
  • In this paper, a new method for finding optimal and short span in Convolutional Self-Doubly Orthogonal(CDO) codes are proposed. This new algorithm based on Parallel Implicitly-Exhaustive search, where we applied dynamic search space reduction methods in order to reduce computational time for finding Optimal Span for R=1/2 rate CDO codes. The simulation results shows that speedup and error correction performance of the new algorithm is better.

A Reduction Method of Search Space for Polyhedral Object Recognition (다면체 인식을 위한 탐색 공간 감소 기법)

  • Lee, Sang-Yong
    • Journal of the Korean Institute of Intelligent Systems
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    • v.13 no.4
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    • pp.381-385
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    • 2003
  • We suggest a method which reduces the search space of a model-base on multiple-view approach for polyhedral object recognition using the ART-1 neural network. In this approach, the model-base is consisted of extracted features from two-dimensional projections observed at the predetermined viewpoints of a viewing sphere enclosing the object.

Algorithm for Search Space Reduction based on Dynamic Heuristic Value Change

  • Kim, Hyung-Soo;Moon, kyung-Seob
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.6
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    • pp.943-950
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    • 2002
  • Real time strategy game is a computer game genre of Playing with human or computer opponents in real time It differs from turn-type computer games in the game process method. Turn type games, such as chess, allow only one Player to move at a time. Real time strategy games allow two or more Players to move simultaneously. Therefore, in real time strategy computer games, the game components' movement plans must be calculated very quickly in order to not disturb other processes such as gathering resources, building structures, and combat activities. There are many approaches, which can reduce the amount of memory required for calculating path, search space, and reactive time of components. (or units). However, existing path finding algorithms tend to concentrate on achieving optimal Paths that are not as important or crucial in real time strategy game. This Paper introduces Dynamic Heuristic Af(DHA*) algorithm which is capable of reducing search space and reactive time of game units and compares with A* algorithm using static heuristic weighting.

Reducing Search Space of A* Algorithm Using Obstacle Information (장애물 정보를 이용한 A* 알고리즘의 탐색 공간의 감소)

  • Cho, Sung Hyun
    • Journal of Korea Game Society
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    • v.15 no.4
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    • pp.179-188
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    • 2015
  • The A* algorithm is a well-known pathfinding algorithm. However, if the information about obstacles is not exploited, the algorithm may collide with obstacles or lead into swamp areas unnecessarily. In this paper, we propose new heuristic functions using the information of obstacles to avoid them or swamp areas. It takes time to process the information of obstacles before starting pathfinding, but it may not cause any problems most of cases because it is not processed in real time. We showed that the proposed methods could reduce the search space effectively through experiments. Furthermore, we showed that heuristic functions using obstacle information could reduce the search space effectively without processing obstacle information at all.

Minimization of Warpage in Injection-molded Parts By Optimal Design of U-type Ribs (U자형 리브의 최적설계에 의한 사출제품의 휨 최소화)

  • Park, Jong-Cheon;Kim, Kwang-Ho;Kim, Kyung-Mo;Koo, Bon-Heung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.7 no.1
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    • pp.53-61
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    • 2008
  • In this research, the layout and geometry of U-type ribs in the part, including significant process conditions, are automatically optimized to reduce part warpage with robustness in consideration. The optimization procedure are based on an iterative redesign methodology integrated with computer aided injection molding simulation, Taguchi's Design of Experiment(DOE), and a direct search-based optimization method. The robustness of a design alternative is efficiently measured by introducing composite noise factor and Taguchi's signal-to-noise ratio. As a solution search methodology, the modified design space reduction method based on orthogonal arrays is employed to exploit an optimal robust design alternative. To illustrate the proposed methodology, a case study is performed on simulation results, where an optimal robust design alternative is obtained with a moderate number of iterations.

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Reconfiguration of Distribution System Using Tabu Search (타부탐색을 이용한 배전계통 재구성)

  • Jeon, Young-Jae;Choi, Seung-Kyoo;Kim, Hoon;Park, Koung-Jong;Kim, Jae-Chul
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1422-1424
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    • 1999
  • This Paper Presents a efficient algorithm for loss reduction of distribution system by automatic sectionalizing switch operation in distribution systems of radial type. To apply tabu search to reconfiguration of distribution system, in this Paper we Propose the several move methods and efficient reconfiguration procedure. We also discuss the tabu search techniques of diversifying the search of solution space as well as the simple tabu search. The experimental results show that the proposed tabu search techniques have the ability to search a good solution.

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Iterative Channel Estimation for Higher Order Modulated STBC-OFDM Systems with Reduced Complexity

  • Basturk, Ilhan;Ozbek, Berna
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.6
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    • pp.2446-2462
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    • 2016
  • In this paper, a frequency domain Expectation-Maximization (EM)-based channel estimation algorithm for Space Time Block Coded-Orthogonal Frequency Division Multiplexing (STBC-OFDM) systems is investigated to support higher data rate applications in wireless communications. The computational complexity of the frequency domain EM-based channel estimation is increased when higher order constellations are used because of the ascending size of the search set space. Thus, a search set reduction algorithm is proposed to decrease the complexity without sacrificing the system performance. The performance results of the proposed algorithm is obtained in terms of Bit Error Rate (BER) and Mean Square Error (MSE) for 16QAM and 64QAM modulation schemes.

Search Space Reduction by Vertical-Decomposition of a Grid Map (그리드 맵의 수직 분할에 의한 탐색 공간 축소)

  • Jung, Yewon;Lee, Juyoung;Yu, Kyeonah
    • Journal of KIISE
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    • v.43 no.9
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    • pp.1026-1033
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    • 2016
  • Path-finding on a grid map is a problem generally addressed in the fields of robotics, intelligent agents, and computer games. As technology advances, virtual game worlds tend to be represented more accurately and more realistically, resulting in an excessive increase in the number of grid tiles and in path-search time. In this study, we propose a path-finding algorithm that allows a prompt response to real-time queries by constructing a reduced state space and by precomputing all possible paths in an offline preprocessing stage. In the preprocessing stage, we vertically decompose free space on the grid map, construct a connectivity graph where nodes are the decomposed regions, and store paths between all pairs of nodes in matrix form. In the real-time query stage, we first find the nodes containing the query points and then retrieve the corresponding stored path. The proposed method is simulated for a set of maps that has been used as a benchmark for grid-based path finding. The simulation results show that the state space and the search time decrease significantly.

A Fast Search Algorithm for Raman Spectrum using Singular Value Decomposition (특이값 분해를 이용한 라만 스펙트럼 고속 탐색 알고리즘)

  • Seo, Yu-Gyung;Baek, Sung-June;Ko, Dae-Young;Park, Jun-Kyu;Park, Aaron
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8455-8461
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    • 2015
  • In this paper, we propose new search algorithms using SVD(Singular Value Decomposition) for fast search of Raman spectrum. In the proposed algorithms, small number of the eigen vectors obtained by SVD are chosen in accordance with their respective significance to achieve computation reduction. By introducing pilot test, we exclude large number of data from search and then, we apply partial distance search(PDS) for further computation reduction. We prepared 14,032 kinds of chemical Raman spectrum as the library for comparisons. Experiments were carried out with 7 methods, that is Full Search, PDS, 1DMPS modified MPS for applying to 1-dimensional space data with PDS(1DMPS+PDS), 1DMPS with PDS by using descending sorted variance of data(1DMPS Sort with Variance+PDS), 250-dimensional components of the SVD with PDS(250SVD+PDS) and proposed algorithms, PSP and PSSP. For exact comparison of computations, we compared the number of multiplications and additions required for each method. According to the experiments, PSSP algorithm shows 64.8% computation reduction when compared with 250SVD+PDS while PSP shows 157% computation reduction.