• Title/Summary/Keyword: Hybrid $A^*$ algorithm

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A Formulation of Hybrid Algorithm for Linear Programming

  • Kim, Koon-Chan
    • Journal of the Korean Operations Research and Management Science Society
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    • v.19 no.3
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    • pp.187-201
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    • 1994
  • This paper introduces an effective hybridization of the usual simplex method and an interior point method in the convergent framework of Dembo and Sahi. We formulate a specific and detailed algorithm (HYBRID) and report the results of some preliminary testing on small dense problems for its viability. By piercing through the feasible region, the newly developed hybrid algorithm avoids the combinatorial structure of linear programs, and several other interesting and important characteristics of this algorithm are also discussed.

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Application of genetic algorithm to hybrid fuzzy inference engine (유전 알고리즘에 의한 Hybrid 퍼지 추론기의 구성)

  • 박세희;조현찬;이홍기;전홍태
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.863-868
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    • 1992
  • This paper presents a method on applying Genetic Algorithm(GA), which is a well-known high performance optimizing algorithm, to construct the self-organizing fuzzy logic controller. Fuzzy logic controller considered in this paper utilizes Sugeno's hybrid inference method, which has an advantage of simple defuzzification process in the inference engine. Genetic algorithm is used to find the optimal parameters in the FLC. The proposed approach will be demonstrated using 2 d.o.f robot manipulator to verify its effectiveness.

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Robust Zero Power Levitation Control of Quadruple Hybrid EMS System

  • Cho, Su-Yeon;Kim, Won-Ho;Jang, Ik-Sang;Kang, Dong-Woo;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1451-1456
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    • 2013
  • This paper presents the improved zero power levitation control algorithm for a quadruple hybrid EMS (Electromagnetic Suspension) system. Quadruple hybrid EMS system is a united form of four hybrid EMS systems one on each corner coupled with a metal plate. Technical issue in controlling a quadruple hybrid EMS system is the permanent magnet's equilibrium point deviation caused by design tolerance which eventually leads to a limited zero power levitation control that only satisfies the zero power levitation in one or two hybrid EMS system among the four hybrid EMS system. In order to satisfy a complete zero power levitation control of the quadruple hybrid EMS system, the proposed method presented in this paper adds a compensating algorithm which adjusts the gap reference of each individual axe. Later, this paper proves the stability and effectiveness of the proposed control algorithm via experiment and disturbance test.

ACCELERATED HYBRID ALGORITHMS FOR NONEXPANSIVE MAPPINGS IN HILBERT SPACES

  • Baiya, Suparat;Ungchittrakool, Kasamsuk
    • Nonlinear Functional Analysis and Applications
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    • v.27 no.3
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    • pp.553-568
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    • 2022
  • In this paper, we introduce and study two different iterative hybrid projection algorithms for solving a fixed point problem of nonexpansive mappings. The first algorithm is generated by the combination of the inertial method and the hybrid projection method. On the other hand, the second algorithm is constructed by the convex combination of three updated vectors and the hybrid projection method. The strong convergence of the two proposed algorithms are proved under very mild assumptions on the scalar control. For illustrating the advantages of these two newly invented algorithms, we created some numerical results to compare various numerical performances of our algorithms with the algorithm proposed by Dong and Lu [11].

A new approach for k-anonymity based on tabu search and genetic algorithm

  • Run, Cui;Kim, Hyoung-Joong;Lee, Dal-Ho
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • v.10 no.4
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    • pp.128-134
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    • 2011
  • Note that k-anonymity algorithm has been widely discussed in the area of privacy protection. In this paper, a new search algorithm to achieve k-anonymity for database application is introduced. A lattice is introduced to form a solution space for a k-anonymity problem and then a hybrid search method composed of tabu search and genetic algorithm is proposed. In this algorithm, the tabu search plays the role of mutation in the genetic algorithm. The hybrid method with independent tabu search and genetic algorithm is compared, and the hybrid approach performs the best in average case.

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Tag Anti-Collision Algorithms in Passive and Semi-passive RFID Systems -Part II : CHI Algorithm and Hybrid Q Algorithm by using Chebyshev's Inequality-

  • Fan, Xiao;Song, In-Chan;Chang, Kyung-Hi;Shin, Dong-Beom;Lee, Heyung-Sub
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.8A
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    • pp.805-814
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    • 2008
  • Both EPCglobal Generation-2 (Gen2) for passive RFID systems and Intelleflex for semi-passive RFID systems use probabilistic slotted ALOHA with Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. A better tag anti-collision algorithm can reduce collisions so as to increase the efficiency of tag identification. In this paper, we introduce and analyze the estimation methods of the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose two new tag anti-collision algorithms, which are Chebyshev's inequality (CHI) algorithm and hybrid Q algorithm, and compare them with the conventional Q algorithm and adaptive adjustable framed Q (AAFQ) algorithm, which is mentioned in Part I. The simulation results show that AAFQ performs the best in Gen2 scenario. However, in Intelleflex scenario the proposed hybrid Q algorithm is the best. That is, hybrid Q provides the minimum identification time, shows the more consistent collision ratio, and maximizes throughput and system efficiency in Intelleflex scenario.

Walking Algorithm of Biped Robots using Hybrid System Approach (하이브리드 시스템 방법을 이용한 이족보행 로봇의 보행 알고리즘)

  • Chu, Jung-Hyun;Lim, Mee-Seub;Lim, Joon-Hong
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.249-251
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    • 2005
  • For walking patterns of biped robots, knee-bent patterns are used in most cases. However, humans are mostly walking with their knees nearly stretched. In this paper, a human-like walking algorithm using hybrid system is proposed for biped robots, The hybrid system consists of the logically constituted discrete system, in which the discrete states are defined by considering the walking characteristics, and the continuous state system used for motor control. It is shown that the proposed algorithm is effective by experimental studies.

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Neural Network Modeling of PECVD SiN Films and Its Optimization Using Genetic Algorithms

  • Han, Seung-Soo
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.1 no.1
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    • pp.87-94
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    • 2001
  • Silicon nitride films grown by plasma-enhanced chemical vapor deposition (PECVD) are useful for a variety of applications, including anti-reflecting coatings in solar cells, passivation layers, dielectric layers in metal/insulator structures, and diffusion masks. PECVD systems are controlled by many operating variables, including RF power, pressure, gas flow rate, reactant composition, and substrate temperature. The wide variety of processing conditions, as well as the complex nature of particle dynamics within a plasma, makes tailoring SiN film properties very challenging, since it is difficult to determine the exact relationship between desired film properties and controllable deposition conditions. In this study, SiN PECVD modeling using optimized neural networks has been investigated. The deposition of SiN was characterized via a central composite experimental design, and data from this experiment was used to train and optimize feed-forward neural networks using the back-propagation algorithm. From these neural process models, the effect of deposition conditions on film properties has been studied. A recipe synthesis (optimization) procedure was then performed using the optimized neural network models to generate the necessary deposition conditions to obtain several novel film qualities including high charge density and long lifetime. This optimization procedure utilized genetic algorithms, hybrid combinations of genetic algorithm and Powells algorithm, and hybrid combinations of genetic algorithm and simplex algorithm. Recipes predicted by these techniques were verified by experiment, and the performance of each optimization method are compared. It was found that the hybrid combinations of genetic algorithm and simplex algorithm generated recipes produced films of superior quality.

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Flow Holding Time based Advanced Hybrid QoS Routing Link State Update in QoS Routing

  • Cho, Kang Hong
    • Journal of the Korea Society of Computer and Information
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    • v.21 no.4
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    • pp.17-24
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    • 2016
  • In this paper, we propose a AH LSU(Advanced Hybrid QoS Routing Link State Update) Algorithm that improves the performance of Hybrid LSU(Hybrid QoS Link State State Update) Algorithm with statistical information of flow holding time in network. AH LSU algorithm has had both advantages of LSU message control in periodic QoS routing LSU algorithm and QoS routing performance in adaptive LSU algorithm. It has the mechanism that calculate LSU message transmission priority using the flow of statistical request bandwidth and available bandwidth and include MLMR(Meaningless LSU Message Removal) mechanism. MLMR mechanism can remove the meaningless LSU message generating repeatedly in short time. We have evaluated the performance of the MLMR mechanism, the proposed algorithm and the existing algorithms on MCI simulation network. We use the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

A Hybrid Genetic Algorithm for Generating Cutting Paths of a Laser Torch (레이저 토치의 절단경로 생성을 위한 혼합형 유전알고리즘)

  • 이문규;권기범
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.12
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    • pp.1048-1055
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    • 2002
  • The problem of generating torch paths for 2D laser cutting of a stock plate nested with a set of free-formed parts is investigated. The objective is to minimize the total length of the torch path starting from a blown depot, then visiting all the given Parts, and retuning back to the depot. A torch Path consists of the depot and Piercing Points each of which is to be specified for cutting a part. The torch path optimization problem is shown to be formulated as an extended version of the standard travelling salesman problem To solve the problem, a hybrid genetic algorithm is proposed. In order to improve the speed of evolution convergence, the algorithm employs a genetic algorithm for global search and a combination of an optimization technique and a genetic algorithm for local optimization. Traditional genetic operators developed for continuous optimization problems are used to effectively deal with the continuous nature of piercing point positions. Computational results are provided to illustrate the validity of the proposed algorithm.