• Title, Summary, Keyword: Cell grouping

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Group Technology Cell Formation Using Production Data-based P-median Model

  • Won Yu Gyeong
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.375-380
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    • 2003
  • This study is concerned with the machine part grouping m cellular manufacturing. To group machines into the set of machine cells and parts into the set of part families, new p-median model considering the production data such as the operation sequences and production volumes for parts is proposed. Unlike existing p-median models relying on the classical binary part-machine incidence matrix which does not reflect the real production factors which seriously impact on machine-part grouping, the proposed p-median model reflects the production factors by adopting the new similarity coefficient based on the production data-based part-machine incidence matrix of which each non-binary entry indicates actual intra-cell or inter-cell flows to or from machines by parts. Computation test compares the proposed p median model favorably.

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A Heuristic Approach to Machine-Part Grouping Cellular Manufacturing (셀 생산방식에서 기계-부품 그룹을 형성하는 발견적 해법)

  • Kim Jin-Seock;Lee Jong-Sub;Kang Maing-Kyu
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.28 no.1
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    • pp.121-128
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    • 2005
  • This paper proposes the heuristic approach for the generalized GT(Group Technology) problem to consider the restrictions which are given the number of cell, maximum number of machines and minimum number of machines. This approach is classified into two stages. In the first stage, we use the similarity coefficient method which is proposed and calculate the similarity values about each pair of all machines and align these values in descending order. If two machines which is selected is possible to link the each other on the edge of machine cell and they don't have zero similarity value, then we assign the machines to the machine cell. In the second stage, it is the course to form part families using proposed grouping efficacy. Finally, machine-part incidence matrix is realigned to block diagonal structure. The results of using the proposed approach are compared to the Modified p-median model.

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.

Joint Cell Grouping and User Association Scheme for Clustered Heterogeneous Cellular Networks (클러스터 이기종 셀룰러 네트워크를 위한 합동 셀 그룹핑 및 사용자 접속 기법)

  • Park, Jin-Bae;Lee, Hyung Yeol;Choi, Uri;Kim, Kwang Soon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.6
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    • pp.520-527
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    • 2013
  • In this paper, a joint cell grouping and user association technique proposed for a semi-dynamic grouped network MIMO in a clustered heterogeneous cellular network (HCN). With the conventional macro BSs, small cells are being overlaid to increase a spectral efficiency per area and these small cells are expected to be concentrated to support exponentially increasing data traffic in hot spot areas. The main culprits of performance degradation in the clustered HCN are interference and load imbalance. The proposed scheme jointly handles them to maximize a proportional-fair metric. It is shown that the proposed technique can largely improve user average rate and proportional fairness among users than any other conventional schemes in the clustered HCN.

An OFDMA-Based Next-Generation Wireless Downlink System Design with Hybrid Multiple Access and Frequency Grouping Techniques

  • Lee Won-Ick;Lee Byeong Gi;Lee Kwang Bok;Bahk Saewoong
    • Journal of Communications and Networks
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    • v.7 no.2
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    • pp.115-125
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    • 2005
  • This paper discusses how to effectively design a next-generation wireless communication system that can possibly provide very high data-rate transmissions and versatile quality services. In order to accommodate the sophisticated user requirements and diversified user environments of the next-generation systems, it should be designed to take an efficient and flexible structure for multiple access and resource allocation. In addition, the design should be optimized for cost-effective usage of resources and for efficient operation in a multi-cell environment. As orthogonal frequency division multiple access (OFDMA) has turned out in recent researches to be one of the most promising multiple access techniques that can possibly meet all those requirements through efficient radio spectrum utilization, we take OFDMA as the basic framework in the next-generation wireless communications system design. So, in this paper, we focus on introducing an OFDMA-based downlink system design that employs the techniques of hybrid multiple access (HMA) and frequency group (FG) in conjunction with intra-frequency group averaging (IFGA). The HMA technique combines various multiple access schemes on the basis of OFDMA system, adopting the multiple access scheme that best fits to the given user condition in terms of mobility, service, and environment. The FG concept and IFGA technique help to reduce the feedback overhead of OFDMA system and the other-cell interference (OCI) problem by grouping the sub-carriers based on coherence band-widths and by harmonizing the channel condition and OCI of the grouped sub-carriers.

A machine-cell formation method based on fuzzy set (퍼지 이론에 기초한 머신-셀 구성방법)

  • 이노성;임춘우
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1565-1568
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    • 1997
  • In this paper, a fuzzy based machine-cell formation algorithm for cellular manufacturing is presented. The fuzzy lovic is employed to express the degree of appropriateness when alternative machnies are specified to process a part shape. For machine grouping, the similarity coefficient based approach is used. The algorithm produces efficient machine cells and part families which maximize the similarity values.

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A study on machine-cell formation in cellular manufacturing based on fuzzy set (퍼지집합에 기초한 셀 생산방식에서의 머신-셀 구성에 관한 연구)

  • Leam, Choon-Woo;Lee, Noh-Sung
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.3
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    • pp.305-310
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    • 1997
  • In this paper, a fuzzy set based machine-cell formation algorithm for cellular manufacturing is presented. The fuzzy logic is emoloyed to express the degree of appropriateness when alternative machines are specified to process a part shape. For machine grouping, the similarity coefficient based approach is used. The algorithm produces efficient machine cells and part families which maximize the similarity values.

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A Grouping Technique for Synchronous Digital Duplexing Systems (동기식 디지털 이중화 시스템을 위한 그룹핑 기법)

  • Ko, Yo-Han;Park, Chang-Hwan;Park, Kyung-Won;Jeon, Won-Gi;Paik, Jong-Ho;Lee, Seok-Pil;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.4C
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    • pp.341-348
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    • 2009
  • In this paper, we propose a grouping technique for the SDD(Synchronous Digital Duplexing) based on OFDMA(Orthogonal Frequency Division Multiple Access). The SDD has advantages of increasing data efficiency and flexibility of resource since SDD can transmit uplink signals and downlink signals simultaneously by using mutual time information and mutual channel information, obtained during mutual ranging process. However, the SDD has a disadvantage of requiring additional CS to maintain orthogonality of OFDMA symbols when the sum of mutual time difference and mutual channel length between AP(access point) and SS(subscriber station) or among SSs are larger than CP length. In order to minimize the length of CS for the case of requiring additional CS in SDD, we proposes a grouping technique which controls transmit timing and receive timing of AP and SS in a cell by classifying them into groups. Performances of the proposed grouping technique are evaluated by computer simulation.

Machine-Part Cell Formation based on Kohonen화s Self Organizing Feature Map (Kohonen 자기조직화 map 에 기반한 기계-부품군 형성)

  • ;;山川 烈
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.315-318
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    • 1996
  • The machine-part cell formation means the grouping of similar parts and similar machines into families in order to minimize bottleneck machines, bottleneck parts, and inter-cell part movements in cellular manufacturing systems and flexible manufacturing systems. The cell formation problem is knows as a kind of NP complete problems. This paper briefly introduces the cell-formation problem and proposes a cell formation method based on the Kohonen's self-organizing feature map which is a neural network model. It also shows some experiment results using the proposed method. The proposed method can be easily applied to the cell formation problem compared to other meta-heuristic based methods. In addition, it can be used to solve large-scale cell formation problems.

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A weighted similarity coefficient method for manufacturing cell formation (제조셀 형성을 위한 가중치 유사성계수 방법)

  • 오수철;조규갑
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.122-129
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    • 1995
  • This paper presents a similarity coefficient based approach to the problem of machine-part grouping for cellular manufacturing. The method uses relevant production data such as part type, production volume, routing sequence to make machine cells and part families for cell formation. A new similarity coefficient using weighted factors is introduced and an algorithm for formation of machine cells and part families is developed. A comparative study of two similarity coefficients - Gupta and seifoddini's method and proposed method - is conducted. A software program using TURBO C has been developed to verify the implementation.

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