• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.105.3-105
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• 2001

In this paper, a current mode two-input maximum (Max) and minimum (Min) operations scheme, which is a useful building block for analog fuzzy inference systems, is presented. The Max and Min operations are incorporated in the same scheme with parallel processing. The proposed scheme comprises a MOS class AB/B configuration and current mirrors. Its simple structure can provide a high efficiency. The performance of the scheme exhibits a very sharp transfer characteristic and high accuracy. The proposed scheme achieves a high-speed operation and is suitable for real-time systems. The simulation results verifying the performances of the scheme are agreed with the expected values.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.52-58
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• 2005

In this paper, we address a real-world periodic vehicle routing problem with time windows (PVRPTW). In addition to the general requirements of single-day vehicle routing problem, each stop has required number of visits within a cycle period in PVRPTW. Thus, we need to determine optimized days of visit for each stop with consideration of the cycle-period days together. The problem also requires consistent vehicle assignment to the stops. We developed a clustering based 3-phase approach for this problem: 1) stop-route assignment, 2) stop-day assignment, and 3) stop sequencing within a single-day route. Using the approach, we could reduce the number of routes and improve the routing efficiency for several real-world problems.

• IE interfaces
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• v.18 no.4
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• pp.370-381
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• 2005

This study is concerned with seeking the optimal allocation(disposition) for maximizing utility of consolidating old fashioned and new air defense weapon system like SAM-X(Patriot missile) and developing efficient solution algorithm based on simulated annealing(SA) algorithm. The SED(selection by effectiveness degree) procedure is implemented with an enhanced SA algorithm in which neighboring solutions could be generated only within the optimal feasible region by using a specially designed PERTURB function. Computational results conducted on the problem sets with a variety of size and parameters shows the significant efficiency of our SED algorithm over existing methods in terms of both the computation time and the solution quality.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.53-56
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• 2003

Recent business environments require a company to communicate frequently with other companies. This makes it essential to use XML (extensible Markup Language) documents. Especially in e-Business environments, change management of documents is important to record and trace the history of the documents. It is also important to reconstruct a certain version of documents that are exchanged among companies. In this paper, we propose a new method of storing a document by detecting changes automatically and reconstructing the document version when a user requests. A prototype system is implemented on top of a workflow system. Our approach provides efficiency of storage space and convenient management of documents.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.3
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• pp.145-155
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• 2004

The design of a communication network has long been a challenging optimization problem. Since the optimal design of a network topology is a well known as a NP-complete problem, many researches have been conducted to obtain near optimal solutions in polynomial time instead of exact optimal solutions. All of these researches suggested diverse heuristic algorithms that can be applied to network design problems. Among these algorithms, a simulated annealing algorithm has been proved to guarantee a good solution for many NP-complete problems. in applying the simulated annealing algorithms to network design problems, generating mechanisms for initial solutions and candidate solutions play an important role in terms of goodness of a solution and efficiency. This study aims at analyzing these mechanisms through experiments, and then suggesting reliable mechanisms.

• Journal of the Korean Operations Research and Management Science Society
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• v.16 no.2
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• pp.118-127
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• 1991

In this paper, criteria and algorithms for the optimal service rate in a closed queueing network have been established. The objective is to minimize total cost. It is shown that system throughput is increasing concave over the service rate of a node and cycle time is increasing convex over the set of service times with a single calss of cubsomers. This enables developing an algorithm using a steepest descent method when the cost function for service rate is convex. The efficiency of the algorithm rests on the fact that the steepest descent direction is readily obtained at each iteration from the MVA algorithm. Several numerical examples are presented. The major application of this research is optimization of facility capacity in a manufacturing system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.19-22
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• 1998

ISP(Information Strategy Planning) is the methodology to light the objective and the business system architecture, and to recognize the strategic situation for the establishment of effective information system in an organization. Customer Needs Research is one of the Research Methodology that analyze the customer needs effectively and use to establish the policy and the direction of corporation. Both have the important role to establish the strategy for the corporation. The former can propose the corporate information strategy in MIS, the latter can be used to research the customer needs about a corporation, to establish the business management strategy and to decide the way corporate must head. But each has studied independently and there is no integrated methodology of ISP and Customer Needs Research. Actually, a lot of corporations still establish ISP to increase the business efficiency rather than to satisfy the customer needs. Customer satisfaction is the final objective of all business so that corporations have to find the customer needs through Customer Needs Research and make ISP oriented to customer satisfaction through the result of Customer Needs Research.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.172-175
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• 1992

This paper proposes the methods to construct the tree-structured database and analyze the distribution system network. In order to cope with an extensive amount of data and the frequent breaker switching operations in distribution systems, the database for system configuration is constructed using binary trees. Once the tree-structured database has been built, the system tracing of distribution network can be rapidly performed. This remarkably enhances the efficiency of data search and easily adapts to system changes due to switching operations. The computation method of fast power flow using tree search strategies is presented. The methods in the paper may be available in the field of distribution system operation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.572-579
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• 2003

With the expansion of e-commerce, E-marketplace has become one of the most discussed topics in recent years. Limited theoretical works, however, have been done to optimize the practical use of e-marketplace systems. Other potential issues aside, this research has focused on this problem: 'the participants waste too much time, effort and cost to find out their best partner in B2B marketplace.' To solve this problem, this paper proposes a system which provides the user-company with the automated and customized brokering service. The system proposed in this paper assesses the weight on the priorities of a user-company, runs the two-stage clustering algorithm with self-organizing map and K-means clustering technique. Subsequently, the system shows the clustering result and user guide-line. This system enables B2B marketplace to have more efficiency on transaction with smaller pool of partners to be searched.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.8-13
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• 2003

This paper considers a continuous-review two-echelon inventory control problem with one-to-one replenishment policy incorporated and with lost sales allowed where demand arrives In a stationary Poisson process The problem Is formulated using METRIC-approximation in a combined approach of pricing and (S-1.S) Inventory policy, for which an iterative solution algorithm is derived with respect to the corresponding one-warehouse multi-retailor supply chain. Specifically, decisions on retail pricing and warehouse inventory policies are made in integration to maximize total profit in the supply chain. The objective function of the model consists of sub-functions of revenue and cost (holding cost and penalty cost). To test the effectiveness and efficiency of the proposed algorithm, numerical experiments are performed The computational results show that the proposed algorithm is efficient and derives quite good decisions