• 한국컴퓨터정보학회논문지
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• 제13권7호
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• pp.199-205
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• 2008

중앙 집중형 컨퍼런스 모델은 컨퍼런스 관리 및 제어가 용이한 장점이 있으나 컨퍼런스 사용자 수가 증가할수록 성능의 저하가 커지므로 확장성에 제약이 있다. 따라서 중앙 집중형 컨퍼런스 모델의 확장성을 개선할 수 있는 새로운 분산형 컨퍼런스 모델들이 최근 제안되고 있다. 이러한 분산형 컨퍼런스 구조에서는 컨퍼런스사용자가정해진 최대값을 넘을 경우 동적으로 새로운 컨퍼런스 서버가 추가되며, 본 논문에서는 이러한 분간형 컨퍼런스 환경에서 주 컨퍼런스 서버가 담당해야 할 컨퍼런스 이벤트 패키지의 처리 방식을 효율화 시킬 수 있는 새로운 방식을 제안하였다. 주 컨퍼런스 서버는 부 컨퍼런스 서버들 및 사용자들과 컨퍼런스 이벤트 패키지를 사용해 정보를 교환하며. 자신이 관리하는 컨퍼런스 정보 데이터베이스에서 컨퍼런스 사용자들에 대한 통지 기능을 분담할 SIP(Session Initiation Protocol) UA(User Agent)들을 선정하여 이들의 목록을 각 컨퍼런스 서버들에게 전송한다. 이를 수신한 각 컨퍼런스 서버들은 선정된 UA들이 컨퍼런스 이벤트 패키지 처리를 분담하도록 하여 컨퍼런스 서버에서의 SIP 신호 처리 부하를 줄일 수 있으며 분산형 컨퍼런스 모델에서의 확장성을 개선시킨다. 제안된 시스템의 성능은 실험을 통하여 분석하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.293-296
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• 2002

This paper discusses a software reliability model for the distributed s-PCT algorithm fur remote sensing applications. The distributed algorithm is designed based on a Manager-Worker threading concept and goes further to use redundancy to achieve fault tolerance. The paper provides a status report on our progress in developing the reliability concept and applying it to create a model for the distributed s-PCT In particular, we are interested ill the algorithm performance versus reliability.

• 한국컴퓨터정보학회논문지
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• 제14권5호
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• pp.85-91
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• 2009

컨퍼런스 참가자 수가 늘어남에 따라 성능이 저하되어 확장성의 제약이 있는 중앙 집중형 컨퍼런스 구조의 문제점을 해결하기 위하여 복수개의 컨퍼런스 서버에 부하를 분담시키는 분산형 컨퍼런스 구조들이 최근 연구되고 있다. 이들 구조에서는 컨퍼런스 참가자 수가 증가함에 따라 동적으로 새로운 컨퍼런스 서버들이 컨퍼런스 환경에 추가된다. 본 논문에서는 이러한 분산형 컨퍼런스 구조에 사용 할 수 있는 새로운 컨퍼런스 정보 데이터 모델을 제안하였다. 제안된 새로운 컨퍼런스 정보 데이터 모델에서는 주 컨퍼런스 서버와 복수개의 부 컨퍼런스 서버들 사이에 컨퍼런스 운영에 필요한 컨퍼런스 정보를 교환할 수 있도록 하기 위한 여러 요소들이 추가되었고, 이를 이용한 컨퍼런스 정보 교환 절차가 제시되었다. 또 이 방식을 사용해 컨퍼런스 정보의 관리와 전체 컨퍼런스 참가자들에 대한 SIP(Session Initiation Protocol) 통지 기능도 컨퍼런스 서버들이 서로 분산 처리 할 수 있게 됨으로써 주 컨퍼런스 서버에 가해지는 부하를 더욱 줄일 수 있게 된다. 제안된 시스템의 성능은 실험을 통하여 분석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.703-705
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• 1999

In this paper, we introduce the direction of arrival(DOA) estimation of distributed signal based on the improved ESPRIT algorithm. Most research on the estimation of DOA has been performed based on the assumption that the signal sources are point sources. However, we consider a two-dimensional distributed signal source model using improved ESPRIT algorithm. In the distributed signal source model, a source is represented by two parameters, the azimuth angle and elevation angle. We address the estimation of the elevation and azimuth angles of distributed sources based on the parametric source modeling in the three-dimensional space with two uniform linear arrays. The array output vector is obtained by integrating a steering vector over all direction of arrival with the weighting of a distributed source density function. We also develop an efficient estimation procedures that can reduce the computational complexity. Some examples are shown to demonstrate explicity the estimation procedures under the distributed signal source model.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1999년도 추계학술대회 논문집
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• pp.325-330
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• 1999

Web-based simulation is one of the most interesting field of simulation research today. Among many research area of web-based simulation, we concern about what a effective way of building simulation model is since creating comprehensive simulation models can be expensive and time consuming. So this paper discusses how to integrate distributed simulation sub-models as objects for constructing the required simulation model which is more large and complex. We introduce two web-oriented methodologies (such as JIDL, CORBA) and the concepts of agent for assisting modelers to integrate simulation models scattered over the web. SINDBAD, which we designed, is a simulation environment which makes it possible constructing a simulation model with distributed model objects on the web and performing the parallel simulation in a distributed way. It is organized according to design patterns in the object oriented concept. Actually we are on the premise that all the distributed objects are originally composed in a CORBA-compatible way to start with our prototype of SINDBAD.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1995년도 추계학술대회발표논문집; 서울대학교, 서울; 30 Sep. 1995
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• pp.46-58
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• 1995

Although numerous distributed database design models and solution algorithms have been developed, very few have been validated. Validation is critical to the successful application of such models to distributed database design. In this paper, we develop a simulation system for distributed database design. We then analyze and validate an average response time model using simulation. The simulation results demonstrate that the average response time model is reasonably accurate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.219-221
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• 1995

This paper proposes a model for simulation and performance evaluation of distributed computer systems(DCS). The model is composed of operating system(OS), resource, task, environment submodel. Task Flow Graph(TFG) is suggested to describe the relation between tasks. This paper considers task response time, the scheduler's ready queue length, utilization of each resource as performance indices. The distributed system of Continuous Annealing Line(CAL) in iron process is simulated with the proposed model.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2005년도 추계학술대회 및 정기총회
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• pp.65-70
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• 2005

Recently, Grid is embossed as a new issue according to the need of cooperation related to distributed resources, data sharing, Interaction and so on. It focuses on sharing of large scale resources, high-performance, applications of new paradigms, which improved more than established distributed computing. Because of the environmental specificity distributed geographically and dynamic, the most important problem in grid environment is to share and to allocate distributed grid resources. This paper proposes supply-driven strategies model that is applicable for resource management in grid environment and presents a optimal resource allocation algorithm based on resource demands. Supply-driven strategies model can offer efficient resource management by transaction allocation based on user demand and provider strategy. This paper implements the supply-driven strategies model on the DEVS modeling and simulation environment and shows the efficiency and excellency of this model by comparing with established models.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.85-89
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• 2002

Development of distributed simulation environment must be required in order to simulate the distributed models regionally and inter-operate with running simulations individually, Simulation based on DEVS formalism is difficult to simulate the distributed models. DEVS formalism is modeling methodology. To specify model, this formalism separates behavior and structure, therefore it is able to design complex model easily. HLA is standard framework of distribute simulation environment, It is defined to facilitate the interoperability and the reusability. RTI (Run Time Infrastructure) is software that provides common service to simulation systems and implementation of the HLA Interface Specification. Method of implementation is that modules cooperating with RTI are added to simulator on DEVS simulation environment. On the DEVS simulation environment (DEVS-Obj -C) that already developed, Highest class of abstract simulator uses service that RTI provide, then This environment is able to change DEVS model into Federate and run distribute simulation that inter-operates with the RTI. Because this distributed simulation environment includes convenience of modeling that obtains through the DEVS formalism and accompanies HLA standard, this environment make it possible to simulate with_ complex systems and heterogeneous simulations

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.976-976
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• 2012

The applicability of a distributed rainfall-runoff model for large river basin flood forecasts is analyzed by applying the model to the Nakdong River basin. The spatially explicit hydrologic model was constructed and calibrated by the several storm events. The assimilation of the large scale Nakdong River basin were conducted by calibrating the sub-basin channel outflow, dam discharge in the basin rainfall-runoff model. The applicability of automatic and semi-automatic calibration methods was analyzed for real time calibrations. Further an ensemble distributed rainfall runoff model has been developed to measure the runoff hydrograph generated for any temporally-spatially varied rainfall events, also the runoff of basin can be forecast at any location as well. The results of distributed rainfall-runoff model are very useful for flood managements on the large scale basins. That offer facile, realistic management method for the avoiding the potential flooding impacts and provide a reference for the construct and developing of flood control facilities.