• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.127-137
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• 1999

This study is concerned with the loading problems in flexible manufacturing system(FMS). The loading problem in FMS is a complex one, when the number of machine and job is increased. It may be time-consuming and even impossible to achieve an optimal solution about this problem mathematically. Thus, a heuristic method is recommended in order to gain near-optimal solutions in a practically acceptable time. A new loading algorithm is developed with a multi-criterion objective of considering the workload unbalance, and maximizing the machine utilization, throughput for critical resources such as the number of tool slots and the number of working hours in a scheduling period and so on. The results of SAS analysis indicated that true average throughput of proposed heuristic loading statistically exceeds that of Shanker and Srinivasulus loading algorithm at the significance level of 0.1.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.5
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• pp.83-89
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• 2010

In this paper, the dynamic response of a CNC 5 Axles machining center was analyzed and then controlled passively by using the dynamic absorber. For the simplification of the theoretical approach, the CNC 5 Axles machining center was modeled as a flexible beam(Bed) having a point mass(Column), two discrete systems(a Table-set and a dynamic absorber). Specifically by using the dynamic absorber, the dynamic response of a Table-set which be caused by the vibration of a flexible beam, was reduced down to the infinitesimal level. The optimal design factors of the dynamic absorber were obtained from the minimization of the cost function. It was found that the natural frequencies of a UT-380 machining center be varied due to the movement of the Table-set. In view of the dynamic response of a Table-set, the larger spring stiffness and mass of the dynamic absorber were found to give the greater reduction.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.167-174
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• 2013

High speed rotor systems with magnetic bearings have been the subject of much research in recent years due to the potential for active vibration control. In this thesis, optimal design was conducted for an 8-pole heteropolar magnetic bearing used in the flexible rotor of a turbo blower. In connection with bearing stiffness, this optimal design process was conducted using a genetic algorithm(GA), which is based on natural selection and genetics. The maximum stiffness of the magnetic bearing-rotor was found by considering the critical speeds of the flexible rotor. As a result, the magnetic bearings were optimized to have maximum stiffness.

• Journal of Korean Institute of Industrial Engineers
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• v.14 no.2
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• pp.131-141
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• 1988

As flexible manufacturing technology has become available across a broad range of applications, an increasingly large number of firms have confronted decisions about when to adopt the FMS technology and the size of FMS at that time. For small to medium size firms that should invest under budget limitation and high investment risk, proper size of FMS adoption at proper time is very important. In this paper the discrete optimal control theory has been used to make decisions about the size and timing of FMS capacity expansion over a planning period. Sensitivity analysis is presented for analysing the behavior of the model to variations of model parameters.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.193-204
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• 1996

본 연구는 FMC(Flexible Manufacturing Cell)에 있어 상호 간섭이 없는 부품의 흐름을 제어하기 위한 교착제거방법(Deadlock Avoidance Method)에 대한 제안으로서, 이 방법이 주요한 장점은 첫째, FMC의 환경을 쉽게 적용시킬 수 있고 둘째, 공정상의 부품에 대한 dispatching 모듈이 협력하도록 설계되어 있다는 것이다. 교착제거방법은 두 개의 모듈로 구성되어 있는데 이는 순환발견알고리즘(A Cycle Detection Algorithm)과 원료주문 정책으로서, 특이할 만한 사항은 순환발견알고리즘을 채용하더라도 원료주문정책이 잘못될 수 있기 때문에 교착제거방법에 있어서 원료주문정책은 매우 중요하다는 것이다. 이를 위하여 교착전의 N-step 교착을 제거하고, 발견할 수 있는 교착제거방법과 N-step의 사전주무정책을 제시하였다.

• The Journal of Society for e-Business Studies
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• v.1 no.2
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• pp.117-131
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• 1996

This paper presents the results of the systems analysis for the FCIM (Flexible Computer Integrated Manufacturing) system at the U.S. Tobyhanna Army Repair Depot, which is one of the RAMP (Rapid Acquisition of Manufactured Part) program sites for CALS implementation in the U.S. military. The FCIM system's acquisition and supply processes are represented by IDEFO function models and FCIM information systems are briefly decribed in this paper. The models presented here can be used at a reference for the development of CALS acquisition and supply systems. In addition. the distinction between input and control information on the IDEFO model it suggested from the practical modeling viewpoint.

• IE interfaces
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• v.12 no.1
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• pp.143-149
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• 1999

In this paper, we propose a workflow framework for the integrated logistics systems. We modelled the logistics activities into workflows, which allow clear specification and flexible modification of business processes. To specify workflows, we used petri-net that is extended to handle with information flows. A framework to implement the integrated logistics system using workflow management technology is proposed. Since logistics is closely related with other parts of enterprise such as manufacturing and accounting, the framework could capture a rich features required for enterprise-wide systems.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.3
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• pp.79-86
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• 2006

Especially, MTO(Make-To-Order) companies take collaborative approaches with their partner companies to make low-price products and/or technologically low intensive products. The collaborative approach to manufacturing requires collaboration with partner companies for inventory review, production plan, and manufacturing to fulfill customer's orders. However, frequent changes of partnerships binder partner companies from sharing production information in effective ways since their information systems have different data architectures and platforms. Therefore, it is required flexible and standardized system integration approach fir effective information sharing. This research studies current status and problems of collaborative production system, proposes an architecture for collaborative production systems based on Web Services which is a standard information technology, and discusses expected effects and the vision of Web Services.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1177-1181
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• 1995

Fixtures are devided into special purpose fixtures, modular fixtures and general purpose fixtures. In this paper, the database of modual fixtures for flexible manufacturing systems is estabilished. Modular fixtures are classified into base plates, supporting elements, locating elements, clamping elements and accessories. Also the concept for the modular fixture design expert system is proposed.