• Title/Summary/Keyword: grouping.

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Machine-part Group Formation Methodology for Flexible Manufacturing Systems (유연생산시스템(FMS)에서의 기계-부품그룹 형성기법)

  • Ro, In-Kyu;Kwon, Hyuck-Chun
    • Journal of Korean Institute of Industrial Engineers
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    • v.17 no.1
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    • pp.75-82
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    • 1991
  • This research is concerned with Machine-Part Group Formation(MPGF) methodology for Flexible Manufacturing Systems(FMS). The purpose of the research is to develop a new heuristic algorithm for effectively solving MPGF problem. The new algorithm is proposed and evaluated by 100 machine-part incidence matrices generated. The performance measures are (1) grouping ability of mutually exclusive block-diagonal form. (2) number of unit group and exceptional elements, and (3) grouping time. The new heuristic algorithm has the following characteristics to effectively conduct MPGF : (a) The mathematical model is presented for rapid forming the proper number of unit groups and grouping mutually exclusive block-diagonal form, (b) The simple and effective mathematical analysis method of Rank Order Clustering(ROC) algorithm is applied to minimize intra-group journeys in each group and exceptional elements in the whole group. The results are compared with those from Expert System(ES) algorithm and ROC algorithm. The results show that the new algorithm always gives the group of mutually exclusive block-diagonal form and better results(85%) than ES algorithm and ROC algorithm.

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Machine-Part Grouping with Alternative Process Plans (대체공정이 있는 기계-부품 그룹 형성)

  • Lee, Jong-Sub;Kang, Maing-Kyu
    • Journal of Korean Institute of Industrial Engineers
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    • v.31 no.1
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    • pp.20-26
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    • 2005
  • This paper proposes the heuristic algorithm for the generalized GT problems to consider the restrictions which are given the number of machine cell and maximum number of machines in machine cell as well as minimum number of machines in machine cell. This approach is split into two phase. In the first phase, we use the similarity coefficient which proposes and calculates the similarity values about each pair of all machines and sort these values descending order. If we have a machine pair which has the largest similarity coefficient and adheres strictly to the constraint about birds of a different feather (BODF) in a machine cell, then we assign the machine to the machine cell. In the second phase, we assign parts into machine cell with the smallest number of exceptional elements. The results give a machine-part grouping. The proposed algorithm is compared to the Modified p-median model for machine-part grouping.

A Look-ahead Heuristic Algorithm for Large-scale Part-Machine Grouping Problems (대단위 부품-기계 군집 문제를 위한 Look-ahead 휴리스틱 알고리듬)

  • Baek Jong-Kwan;Baek Jun-Geol;Kim Chang Ouk
    • Journal of the Korean Operations Research and Management Science Society
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    • v.30 no.3
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    • pp.41-54
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    • 2005
  • In this paper, we consider a multi-objective machine cell formation problem. This problem Is characterized as determining part route families and machine cells such that total sum of inter-ceil part movements and maximum machine workload imbalance are simultaneously minimized. Together with the objective function, alternative part routes and the machine sequences of part routes are considered In grouping Part route families. Due to the complexity of the problem, a two-phase heuristic algorithm is proposed. And we developed an n-stage look-ahead heuristic algorithm that generalizes the roll-out algorithm. Computational experiments were conducted to verify the performance of the algorithm.

Generalized Clustering Algorithm for Part-Machine Grouping with Alternative Process Plans (대체가공경로를 가지는 부품-기계 군집 문제를 위한 일반화된 군집 알고리듬)

  • Kim, Chang-Ouk;Park, Yun-Sun;Jun, Jin
    • Journal of Korean Institute of Industrial Engineers
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    • v.27 no.3
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    • pp.281-288
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    • 2001
  • We consider in this article a multi-objective part-machine grouping problem in which parts have alternative process plans and expected annual demand of each part is known. This problem is characterized as optimally determining part sets and corresponding machine cells such that total sum of distance (or dissimilarity) between parts and total sum of load differences between machines are simultaneously minimized. Two heuristic algorithms are proposed, and examples are given to compare the performance of the algorithms.

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A self-organizing neural networks approach to machine-part grouping in cellular manufacturing systems (셀 생산 방식에서 자기조직화 신경망을 이용한 기계-부품 그룹의 형성)

  • 전용덕;강맹규
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.21 no.48
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    • pp.123-132
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    • 1998
  • The group formation problem of the machine and part is a very important issue in the planning stage of cellular manufacturing systems. This paper investigates Self-Organizing Map(SOM) neural networks approach to machine-part grouping problem. We present a two-phase algorithm based on SOM for grouping parts and machines. SOM can learn from complex, multi-dimensional data and transform them into visually decipherable clusters. Output layer in SOM network is one-dimensional structure and the number of output node has been increased sufficiently to spread out the input vectors in the order of similarity. The proposed algorithm performs remarkably well in comparison with many other algorithms for the well-known problems shown in previous papers.

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An efficient recognition of round objects using the curve segment grouping (곡선 조각의 군집화에 의한 둥근 물체의 효과적인 인식)

  • 성효경;최흥문
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.9
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    • pp.77-83
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    • 1997
  • Based on the curve segment grouping, an efficient recognition of round objects form partially occuluded round boundaries is proposed. Curve segments are extracted from an image using a criterion based on the intra-segment curvature and local contrast. During the curve segment extraction the boundaries of pratially occluding and occuluded objects are segmented to different curve segments. The extracted segments of constant intra-segment curvature are grouped to different curve segments. The extracted segments of constant intra-segment curvature are grouped nto a round boundary by the proposed grouping algorithm using inter-segment curvature which gives the relatinships among the curve segments of the same round boundary. The 1st and the 2nd order moments are used for the parameter estimation of the best fitted ellipse with round boundary, and then recognition is perfomed based on the estimated parameters. The proposed scheme processes in segment unit and is more efficient in computational complexity and memory requirements those that of the conventional scheme which processed in pixel units. Experimental results show that the proposed technique is very efficient in recognizing the round object sfrom the real images with apples and pumpkins.

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An Integer Programming Approach to the PCB Grouping Problem

  • Yu Sungyeol;Kim Duksung;Park Sungsoo
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2003.05a
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    • pp.394-401
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    • 2003
  • We consider a PCB grouping problem arising from the electronic industry. Given a surface mounting device, several types of PCBs and a number of component feeders used to assemble the PCBs. the optimization problem is the PCB grouping problem while minimizing setup time of component feeders. We formulate the problem as an Integer programming model and propose a column generation approach to solve the Integer programming formulation. In this approach we decompose the original problem Into master problem and column generation subproblem Starting with a few columns in the master problem. we generate new columns successively by solving subproblem optimally. To solve the subproblem. we use a branrh-and-rut approach. Computational experiments show that our solution approach gives high quality solutions in a reasonable computing time.

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A study on machine-part group formation for designing the cellular manufacturing systems (셀형 제조시스템설계를 위한 machine-part의 그룹형성에 관한 연구)

  • 김성집;김낙현
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1996.04a
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    • pp.125-130
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    • 1996
  • This study is concerned with a heuristic algorithm that can make effectively the machine-part grouping in early stage for designing cellular manufacturing systems. By enhancing the Close Neighbour Algorithm(CNA), the proposed algorithm is concerned with making the machine-part grouping that can maximize machine utilization and minimize part's intercell movement by reducing exceptional elements. The algorithm is tested against existing algorithms in solving several machine-part initial matrices extracted from references and obtained by using random number. Test results shows that a solution matrix of the algorithm has superior grouping efficiency to Close Neighbour Algorithm.

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A Grouping Genetic Algorithm for the Pick-up and Delivery Problem with Time Windows (시간대 제약이 있는 차량 수.배송 문제를 위한 Grouping Genetic Algorithm)

  • Song Jeong-Eun;Kim Hyeong-Seok;Lee Myeong-Ho;Kim Nae-Heon
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2006.05a
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    • pp.33-36
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    • 2006
  • OR 기법이 현실에 성공적으로 적용된 분야 중 하나가 차량 경로 문제 풀이며 이 분야에 대한 연구는 꾸준히 진행되어 오고 있다. 시간대 제약이 있는 차량 수 배송 문제는 기존의 차량 배송 문제에서 더욱 진보된 형태의 문제이다. 많은 연구가 있어왔지만, 이러한 형태의 문제들은 NP-hard 형태의 문제이므로 meta-heuristic 기법들이 많이 사용되었다. 유전자 알고리즘에 비해 타부 서치 기법이 많이 사용되었는데, 이는 시간대 제약이 있는 차량 수 배송 문제의 경우 유전자 알고리즘의 근간인 염색체 형태로 표현하기가 쉽지 않기 때문이다. 이에 본 논문에서는 시간대 제약이 있는 차량 수 배송 문제를 다수의 차량을 사용하는 Grouping Genetic Algorithms을 적용하여 이러한 어려움을 해결하였다. 또한, 기존의 유전자 알고리즘들은 초기 해 집단을 임의 선택 방식으로 구성하였지만, 초기 해 집단 구성을 heuristic 기법을 사용하여 적합도 함수 값이 좋은 해들로 구성하여 기존에 사용된 알고리즘들과 성능을 비교 분석하고자 한다.

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Hierarchical Age Estimation based on Dynamic Grouping and OHRank

  • Zhang, Li;Wang, Xianmei;Liang, Yuyu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.7
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    • pp.2480-2495
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    • 2014
  • This paper describes a hierarchical method for image-based age estimation that combines age group classification and age value estimation. The proposed method uses a coarse-to-fine strategy with different appearance features to describe facial shape and texture. Considering the damage to continuity between neighboring groups caused by fixed divisions during age group classification, a dynamic grouping technique is employed to allow non-fixed groups. Based on the given group, an ordinal hyperplane ranking (OHRank) model is employed to transform age estimation into a series of binary enquiry problems that can take advantage of the intrinsic correlation and ordinal information of age. A set of experiments on FG-NET are presented and the results demonstrate the validity of our solution.