• 대한전기학회논문지:시스템및제어부문D
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• 제53권9호
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• pp.630-637
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• 2004

In this paper, we present a local reduced-order observer for a class of nonlinear systems that have full robust relative degree. The proposed observer utilizes the coordinate change which transforms a nonlinear system into an approximate normal form. The proposed reduce order observer is applied to a ball and beam system, and simulation results show that substantial improvement in the performance was achieved compared with the jacobian linearization observers.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.1117-1123
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• 2005

This paper deals with a new automated guided vehicle (AGV) control system for distributed control. Proposed AGV control system adapts the multi-agent technology. The system is composed of two types of controller: routing and order. The order controller is in charge of assignment of orders to AGVs. Through the bidding-based negotiation with routing controllers, the order controller assigns a new order to the proper AGV. The order controller announces order information to the routing controllers. Then the routing controllers generate a routing schedule for the order and make a bid according to the routing schedule. If the routing schedule conflicts with other AGV's one, the routing controller makes an alternative through negotiation with other routing controllers. The order controller finally evaluates bids and selects one. Each controller consists of a set of agents: negotiation agent, decision making agent and communication agent. We focus on the agent architecture and negotiation-based AGV scheduling algorithm. Proposed system is validated through an exemplary scenario.

• 산업경영시스템학회지
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• 제33권3호
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• pp.10-21
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• 2010

Promotion system can be used as strategical management weapon to enhance the sales power. Planned order system has some similarities with promotion system to create purchasing power and to supply the service parts with low price on purpose. The only difference is whether it is prearranged event or not. The effectiveness of forecasting has increased with normal state of ordering process. However, the accuracy of forecasting has diminished with irregular state of ordering, such as demand occurrences by unexpected climate change or intended planned order by the company. A planned order system is examined through the process of computing the effectiveness on the basis of forecasting in this paper. And it is suggested that how to increase the accuracy of forecasting capability under the planned order system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.89-92
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• 2002

As the use of Internet being generalized, ordering system can be easily achieved on the Web so that the direct sailing system is replaced the various types of Built-To-Order system. It is important to give the up-to-date information to the end-user in order to build the Built-To-Order system. Recently, the way of providing information is updating the product related information continuously. In this study, we provide the method that can be streamlined Product Data Management System which manages a creation and update for product information into the direct BTO system in order to achieve the newest information. This methodology is not only transferring the information but also processing the information in an appropriate form. So this paper is going to cover the various point of view of information processing.

• 대한수학회지
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• 제45권2호
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• pp.405-423
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• 2008

By using critical point theorem, we study a higher order difference system, and obtain some new sufficient conditions ensuring the existence of periodic solutions for such a system.

• 산업공학
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• 제14권1호
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• pp.9-19
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• 2001

Production planning and control system plays an important role in manufacturing companies because it determines all production capacity planning, material procurement planning, and production scheduling which are needed in the process of producing products. Many researches on production planning and control system have been conducted for many manufacturing companies for recent decade. But, a considerable research achievement has mainly been obtained on the forecast-driven production for a make-to-stock and an assemble-to-order. The reason is that there are some hardships such as difficulties of standardizing product information, the frequent changes of design and material, and the unexpected dynamic events that influence the production of customer's order in a make-to-order or an engineering-to-order environments. By these characteristics and their complexities, some studies for production planning and control system in a make-to-order environment are presented recently. In this paper, we present the framework of the hietachical production planning and control for a make-to-order environment with dynamic events. In order to illustrate the usefulness of the proposed framework for a hietachical production planning and control, the information system for a make-to-order production was implemented with the object of the company of producing electricity transformer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.93-96
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• 2002

The manufacturing paradigm has shifted dramatically over the past decade from “push” or mass production mode to “pull” or customer-driven, order-based manufacturing mode, as multitudes of customers now demand mass customization of configurable products. As a means to achieve such rapidly responsive manufacturing system, Advanced Planning System (APS) has become an essential software tool for achieving modern “build-to-order” and “configure-to-order” manufacturing environment. APS enables manufacturers to respond to variety of customer demands In real time by instantly configuring manufacturing processes based on specifications described in each purchase orders and providing capable-to-promise information directly to customer by performing rapid “what-if” manufacturing simulated scenarios. This paper discusses the working of such system as well as the business processes that incorporate such systems to enable efficient “build-to-order” environment.

• 산업경영시스템학회지
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• 제14권24호
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• pp.149-154
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• 1991

The one of the important problems in the design of queueing systems is the decision of the order of service stations. The object of this problem is the decision of the order that minimizes the expected sojourn time per customer in the given arrival process and service time distributions. In this paper, the tandem queueing system in series is studied with the emphasis on the optimal order of the tandem queueing system which has three stations with single servers. In one system, customers arrive at the first station with Poisson process. This system is composed of service stations with a constant, a general distribution and a Exponential distribution is studied. To select the optimal order after the orders of each pair of two stations is decided, it is compared the two orders of system. With this results, total expected delay of the systems which has three stations is compared. The result is the best that service station with constant time is on the first place, then the service station with general distribution and the service station with Exponential distribution is followed. And the other system is consist of service stations with a constant and two probabilistic distributions. In this case, two probabilistic distributions has a non-overlapping feature. It is the optimal order that the service station with constant time is on the first place then the service station with longer service time and the service station with shorter service time is followed.

• 한국산학기술학회논문지
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• 제17권3호
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• pp.218-223
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• 2016

본 논문에서는 광통신시스템의 수신기에서 Butterworth 필터의 차수가 수신기의 감도에 미치는 상관관계에 대해 연구를 수행하였다. 일반적인 경우에는 필터의 차수가 증가하면 할수록 수신기의 감도가 증대된다. 이는 필터의 차수가 증가할수록 필터의 규격화 주파수의 응답이 구형파와 비슷해지기 때문이다. 그러한 이유로 수신기의 감도를 증가시키기 위해서 필터의 차수를 높이는 방법을 이용한다. 그러나 필터의 차수를 높이는 방법을 사용하면 시스템이 복잡해지고 시스템의 단가를 상승시키는 요인이 된다. 따라서 본 논문에서는 시스템을 간단히 구성하여 시스템의 단가를 낮추기 위한 방법을 모색하기 위해 수신기의 감도와 필터의 차수와의 상관관계에 대해 연구를 수행하였다. 시뮬레이션 결과 필터의 차수를 증가시키면 수신기의 감도가 상승하는 것을 확인 할 수 있었다. 또한 수신기의 감도를 감소시키지 않는 범위의 버터워스 필터의 차수는 2로 확인되었다. 따라서 본 논문의 결과를 사용한다면 저렴한 광시스템의 수신기를 구현이 가능하리라 사료된다.

• East Asian mathematical journal
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• 제24권1호
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• pp.111-123
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• 2008

In this paper, we introduce a new system of first-order impulsive fuzzy differential equations. By using Banach fixed point theorem, we obtain some new existence and uniqueness theorems of solutions for this system of first-order impulsive fuzzy differential equations in the metric space of normal fuzzy convex sets with distance given by maximum of the Hausdorff distance between level sets.