• Title/Summary/Keyword: branch-and-bound

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An Assembly-Type Flowshop Scheduling Problem with Outsourcing Allowed (부품외주를 고려한 조립형 Flowshop 일정계획문제 연구)

  • Juhn, Jae-Ho
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.29 no.4
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    • pp.34-42
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    • 2006
  • This paper considers an assembly-type flowshop scheduling problem in which each job is assembled with two types of components. One type of the components is outsourced with positive lead time but the other type is fabricated in-house at the first stage. The two types of the components should be prepared at the first stage before starting the assembly operation for each job at the second stage. The objective is to schedule the jobs so that the makespan is minimized. Some solution properties and lower bounds are derived and incorporated into a branch and bound algorithm. Also, an efficient heuristic is developed. The performances of the proposed branch and bound algorithm and heuristic are evaluated through computational experiments.

Optimizing Zone-dependent Two-level Facility Location Problem (Zone을 고려한 2단계 시설배치 계획 최적화)

  • Lim, Sung-Hoon;Sung, Chang-Sup;Song, Sang-Hwa
    • IE interfaces
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    • v.24 no.4
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    • pp.341-350
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    • 2011
  • This paper considers a problem of locating both distribution centers and retailers in a zone-dependent two-level distribution network where either a distribution center or a retailer should be located in each zone. Customer demands of each zone should be satisfied directly from either its own distribution center or its own retailer being supplied from a distribution center of another zone. The objective of the proposed problem is to minimize total cost being composed of distribution center/retailer setup costs and transportation costs. In the analysis, the problem is proved to be NP-hard, so that a branch-and-bound algorithm is derived for the problem. Numerical experiments show that the proposed branch-and-bound algorithm provides the optimal solution efficiently for some small problems.

Scheduling Orders for Minimizing Total Weighted Tardiness (가중납기지연시간을 고려한 최적 주문처리순서에 관한 연구)

  • Lee, Ik-Sun;Yoon, Sang-Hum
    • Journal of the Korean Operations Research and Management Science Society
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    • v.33 no.2
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    • pp.87-101
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    • 2008
  • This paper considers an order scheduling model to minimize the total weighted tardiness of orders. Each order requires different types of products. Each type of product is manufactured on its dedicated machine specified in advance. The completion time of each order is represented by the time when all the products belonging to the order are completed. The objective of this paper is to find the optimal production schedule minimizing the total weighted tardiness of a finite number of orders. In the problem analysis, we first derive a powerful solution property to determine the sequence of two consecutive orders. Moreover, two lower bounds of objective are derived and tested along with the derived property within a branch-and-bound scheme. Two efficient heuristic algorithms are also developed. The overall performances of the proposed property, branch-and-bound and heuristic algorithms are evaluated through various numerical experiments.

An Improved Best-First Branch and Bound Algorithm for Unconstrained Two-Dimensional Cutting Problems (무제한 2차원 절단문제에 대해 개선된 최적-우선 분지한계 해법)

  • Yoon Ki-Seop;Bang Sung-Kyu;Kang Maing-Kyu
    • Journal of the Korean Operations Research and Management Science Society
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    • v.30 no.4
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    • pp.61-70
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    • 2005
  • In this Paper, we develop an improved branch and bound algorithm for the (un)weighted unconstrained two-dimensional cutting problem. In the proposed algorithm, we improve the branching strategies of the existing exact algorithm and reduce the size of problem by removing the dominated pieces from the problem. We apply the newly Proposed definition of dominated cutting pattern and it can reduce the number of nodes that must be searched during the algorithm procedure. The efficiency of the proposed algorithm is presented through comparison with the exact algorithm known as the most efficient.

A Branch and Bound Algorithm for Two-Stage Hybrid Flow Shop Scheduling : Minimizing the Number of Tardy Jobs (2단계 혼합흐름공정에서 납기 지연 작업수의 최소화를 위한 분지한계 알고리듬)

  • Choi, Hyun-Seon;Lee, Dong-Ho
    • Journal of Korean Institute of Industrial Engineers
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    • v.33 no.2
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    • pp.213-220
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    • 2007
  • This paper considers a two-stage hybrid flow shop scheduling problem for the objective of minimizing the number of tardy jobs. Each job is processed through the two production stages in stages, each of which has multiple identical parallel machines. The problem is to determine the allocation and sequence of jobs at each stage. A branch and bound algorithm that gives the optimal solutions is suggested that incorporates the methods to obtain the lower and upper bounds. Dominance properties are also suggested to reduce the search space. To show the performance of the algorithm, computational experiments are done on randomly generated problems, and the results are reported.

A Vertical File Partitioning Method Using SOFM in Database Design (데이터베이스 설계에서 SOFM 을 이용한 화일 수직분할 방법)

  • Shin, K.H.;Kim, J.Y.
    • Journal of Korean Institute of Industrial Engineers
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    • v.24 no.4
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    • pp.661-671
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    • 1998
  • It is important to minimize the number of disk accesses which is necessary to transfer data in disk into main memory when processing transactions in physical database design. A vertical file partitioning method is used to reduce the number of disk accesses by partitioning relations vertically and accessing only necessay fragments. In this paper, SOFM(Self-Organizing Feature Maps) network is used to solve vertical partitioning problems. This paper shows that SOFM network is efficient in solving vertical partitioning problem by comparing approximate solution of SOFM network with optimal solution of N-ary branch and bound method. And this paper presents a heuristic algorithm for allocating duplicate attributes to vertically partitioned fragments. As branch and bound method requires particularly much computing time to solve large-sized problems, it is shown that SOFM network is able to overcome this limitation of branch and bound method and solve large-sized problems efficiently in a short time.

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Unification of Kohonen Neural network with the Branch-and-Bound Algorithm in Pattern Clustering

  • Park, Chang-Mok;Wang, Gi-Nam
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.06a
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    • pp.134-138
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    • 1998
  • Unification of Kohone SOM(Self-Organizing Maps) neural network with the branch-and-bound algorithm is presented for clustering large set of patterns. The branch-and-bound search technique is employed for designing coarse neural network learning paradaim. Those unification can be use for clustering or calssfication of large patterns. For classfication purposes further usefulness is possible, since only two clusters exists in the SOM neural network of each nodes. The result of experiments show the fast learning time, the fast recognition time and the compactness of clustering.

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Development of a Branch-and-Bound Global Optimization Based on B-spline Approximation (비스플라인 분지한계법 기반의 전역최적화 알고리즘 개발)

  • Park, Sang-Kun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.2
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    • pp.191-201
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    • 2010
  • This paper presents a new global optimization algorithm based on the branch-and-bound principle using Bspline approximation techniques. It describes the algorithmic components and details on their implementation. The key components include the subdivision of a design space into mutually disjoint subspaces and the bound calculation of the subspaces, which are all established by a real-valued B-spline volume model. The proposed approach was demonstrated with various test problems to reveal computational performances such as the solution accuracy, number of function evaluations, running time, memory usage, and algorithm convergence. The results showed that the proposed algorithm is complete without using heuristics and has a good possibility for application in large-scale NP-hard optimization.

An Optimal Scheduling Method based upon the Lower Bound Cost Estimation (하한비용 추정에 바탕을 둔 최적 스케쥴링기법)

  • 엄성용;전주식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.28A no.12
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    • pp.73-87
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    • 1991
  • This paper presents a new approach to the scheduling problem in the high level synthesis. In this approach, iterative rescheduling processes starting with ASAP(As Soon As Possible) scheduling result are performed in a branch-and-bound manner so to arrive at the scheduling result of the lowest hardware cost under the given timing constraint. At each iteration step, only the selected nodes are considered for rescheduling, and the lower bound cost estimation is performed to avoid the unnecessary attempts to search for an optimal result. This branch-and-bound method turns out to be effective in pruning the search space, and thus reducing run time considerably in many cases.

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Improvment of Branch and Bound Algorithm for the Integer Generalized Nntwork Problem (정수 일반네트워크문제를 위한 분지한계법의 개선)

  • 김기석;김기석
    • Journal of the Korean Operations Research and Management Science Society
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    • v.19 no.2
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    • pp.1-19
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    • 1994
  • A generalized network problem is a special class of linear programming problem whose coefficient matrix contains at most two nonzero elements per column. A generalized network problem with 0-1 flow restrictions is called an integer generalized network(IGN) problem. In this paper, we presented a branch and bound algorithm for the IGN that uses network relaxation. To improve the procedure, we develop various strategies, each of which employs different node selection criterion and/or branching variable selection criterion. We test these solution strategies and compare their efficiencies with LINDO on 70 randomly generated problems.

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