• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.793-794
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• 2005

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.503-509
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• 2001

분산환경에서 효율적인 분산 서비스를 제공하기 위해 TINA 콘소시엄과 OMG CORBA에서는 객체지향기술을 적용한 분산 객체 플랫폼의 제안과 다양한 서비스의 요구사항들 정립하고 있다. 그러나, 어플리케이션의 규모가 점점 커지고 분산화 됨에 따라 객체들간의 서비스 및 관리 인터페이스가 매우 복잡해지고 있다. 이러한 문제들을 해결하기 위해서 새로운 객체그룹 모델의 제안과 객체그룹하에서 도입될 수 있는 객체 관리 및 서비스를 위한 요구사항들이 필요하다. 본 논문에서는 TINA에서 제안한 그룹객체 정의를 도입하여 현재 분산 시스템의 표준으로 사용하는 CORBA 기반에서 분산된 객체들을 효율적으로 관리할 수 있는 시스템을 제안한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
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• pp.1621-1624
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• 2003

As the entities participating Grid become larger, performance requirement for the LDAP-based GIS(Grid Information Service) goes beyond that provided by a stand-alone single LDAP server. This entails the exploration of distributed LDAP systems. This paper presents the performance evaluation respectively for a distribution-based and a replication-based LDAP model. The analysis is based on an analytic performance model for each distributed system which is obtained by applying the M/M/1 queuing model. The performance evaluation made to these analytic models reveals that the distribution-based and the replication-based model show a significant tradeoff in their performance with respect to the system size as well as the amount of system load.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2009년도 추계학술대회
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• pp.3-10
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• 2009

When the measurement method for a performance variable is destructive or expensive, it is profitable to replace the performance variable with a highly correlated surrogate variable. In this paper we propose screening procedures using a surrogate variable with specified producer's and consumer's risks. Blending the basic concepts of acceptance sampling plans and screening procedures, the proposed model can be used effectively by quality professionals. Two models are considered: the normal model with dichotomous performance and continuous surrogate variables, and the bivariate normal model with continuous performance and surrogate variables. It is assumed the surrogate variable given the performance variable is normally distributed in the normal model, and performance and surrogate variables are jointly normally distributed in the bivariate normal model. For the two models, Producer's and consumer's risks are derived, and methods of finding the optimal screening procedures are presented. Numerical examples are also given.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.1033-1039
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• 2005

Parallel and distributed simulation is concerned with the efficient execution of large-scale discrete event simulation models on multiprocessors and distributed platforms. After the development of WWW, many efforts in the parallel and distributed simulation have been made for modeling, particularly building simulation languages and creating model libraries that can be assembled and executed over WWW. However, web-based parallel and distributed simulation is restricted by heterogeneous computing environments. Recently, the advent of XML and web services technology has made these efforts enter upon a new phase. Especially, the web services as a distributed information technology have demonstrated powerful capabilities for scalable interoperation of heterogeneous systems. This paper aims to develop and evaluate the parallel and distributed simulation using the web services technology. In particular, a prototype multi-pass simulation framework is implemented using Java-based web services technology. It focuses on the efficiency of multi-pass simulation used for optimization through the distribution of simulation replication to several simulation service providers. The development of parallel and distributed simulation using web services will help solve efficiently large-scale problems and also guarantee interoperability among heterogeneous networked systems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.181-185
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• 2001

This paper deals with the dynamic stability of a disc brake pad taking into account of its shear deformation and rotary inertia. A brake pad can be modeled as a beam like model subjected to distributed friction forces and having two translational springs. The study of this model is intended to provide a fundamental understanding of dynamic stability of drum brake pad. Governing equations of motion are derived from extended Hamilton's principle and their corresponding numerical solutions are obtained by applying the finite element formulation. The critical distributed friction force and the instability types are investigated bt changing two translational spring constants, rotary inertia parameter and shear deformation parameter. Also, the changes of eigen-frequencies of a beam determining instability types are investigated for various combinations of two translational spring constants.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2005년도 춘계학술발표대회
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• pp.213-216
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• 2005

In this paper, we propose the redirect streaming service model to enhance resurgent ability. The system consists of a redirect server, local streaming servers and clients. A redirect server searches the best streaming server. And streaming servers starts a requested service or resumes it when in a trouble. RTSP/RTP is one of the effective solutions to improve QOS in VOD, however a service can be broken off by an overloaded server or network especially in live. We designed and implemented not only a distributed streaming system that solves the broken-off service to enhance a resurgent system, but also DSSP, distributed streaming service protocol, which is adopted to implement this model. Those will improve the performance of streaming service using RTP/RTSP and be contributed to a real time streaming research to solve a service trouble.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.333-336
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• 2008

This paper resents a theoretical analysis for the grounding impedance influenced by the ground rod's dimension using the distributed parameter model. In this paper, EMTP and Matlab Program were used to simulate the distributed parameter model and to analyze the frequency-dependent characteristics of the ground rods. We compared two kinds of ground rods having different dimensions and the frequency-dependent characteristics of two ground rods were quite different from each other. It is estimated that these different characteristics are caused by the distributed parmeters which are changed by the length of ground rod.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2531-2533
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• 2002

In this paper, we evaluate feasibility of an object-oriented method in a distributed real-time control environment through the prediction of delay expected. We adopt CAN as the distributed network and the application layer of the CAN is composed of client/server communication model of COM and surroundings for the support of real-time capability of the COM. Mathematical models formalizing delays which are predicted to invoke in the COM architecture are proposed. Sensors and actuators which are widely used in distributed network-based systems are represented by COM objects in this paper. It is expected that the mathematical models can be used to protect distributed network-based systems from violation of real-time features by the COM.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.307-311
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• 2006

Distributed Coordination Function (DCF) in IEEE 802.11 and Enhanced Distributed Channel Access (EDCA) in IEEE 802.11e are contention-based access mechanism in Wireless LAN. Both DCF and EDCA reduce collisions based on inter-frame space (IFS) and backoff mechanisms. However, collisions are unavoidable even with the two mechanisms. Especially, in the EDCA model, the collision can be classified into interclass and intraclass collision. To eliminate interclass collision in Wireless LAN, we propose an interclass collision protection (ICP) scheme by employing contention protection period (CPP) after backoff, Analysis is performed for one dimensional EDCA model and for the proposed ICP based EDCA model.