• 한국전자거래학회지
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• 제5권1호
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• pp.105-122
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• 2000

Enterprise integration and virtual enterprise are practical visions of industrial information implementations in the information society. In these environments, the distributed and heterogeneous data sources should be exchanged and shared in effective and integrated way. However, the distributed and heterogeneous data sources are managed by independent and heterogeneous computer systems, thus system users and developers are faced difficulties in implementing enterprise integration environments, In this study, we designed and developed a database broker system utilizing a routing broker method to provide transparent location access mechanisms for the distributed and heterogeneous data sources. The proposed mechanism is designed to act as a middle tier between clients and multiple servers, and adopts Java, CORBA, and JDBC as its state-of-the-art techniques.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 컴퓨터소사이어티 추계학술대회논문집
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• pp.141-144
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• 2003

This paper proposes the distributed virtual environment framework for collaboration between heterogeneous platforms. The proposed system consists of Client, Content Server(CS), and Reflector Server(RS). The Client is composed of VR library(VRL), Interaction Manager(IM), Distributed Interaction Manager(DIM), and Network Interface(NI). The proposed Client structure can support various display environments. The XML-based IM and DIM lets the users define and add the interactions. The proposed Server structure synchronizes the distributed interaction between heterogeneous platforms and provides transparency to the users. Therefore, the proposed framework enables the users to implement virtual collaboration environment for their tasks. Moreover, it can also be used for research and development activities between a large number of the remote users. The usefulness of the framework was verified by applying it to the virtual heritage tour system.

• 한국군사과학기술학회지
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• 제15권4호
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• pp.381-389
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• 2012

In the existing naval combat system, integrated management is done based on subsystems that make up the system. The naval combat system, however, is a large-scale distributed system made up of subsystems of diverse heterogeneous environments. Although each of the subsystems can be easily managed because they are on the same platform, it is extremely difficult to integrate and manage as a single entity all subsystems that make up the naval combat system because the heterogeneous environments and distributed systems have to be taken into account. In fact, there hasn't been a technique available to integrate and manage subsystems that make up the naval combat system, until now. In this paper, the architecture of an integrated management system is designed and implemented to provide the user with various services. Furthermore, a system that can manage subsystems of the naval combat system in an integrated way is developed.

• 정보기술과데이타베이스저널
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• 제7권2호
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• pp.33-45
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• 2000

Uniview system is a client-server system that runs on heterogeneous distributed systems and supports the debugging of various kinds of programs. Its client system provides a unified debugging concept and interface on various debuggers of heterogeneous hosts. Its server system provides debugging services and features openness and scalability by interoperating with one or more debugger processes existing on the same host. Based on FSF(Free Software Foundation)'s gdb and Sun Microsystems's dbx. Uniview system supports C/C++ programming language in various UNIX environments as well as Windows environments. The proposed system was designed and implemented to support the JAVA language, which is prevalently used in recent heterogeneous distributed systems and was partly extended to make a clear analysis of JAVA class file structure. Sun Microsystems's Jdb supplied as a JAVA debugger has very limited functions compared to other programming language debugger. In this paper, Uniview as a JAVA debugging system was implemented to provide debugging technologies which are necessary to debug Java applications but missing in current JAVA language as well as to provide its users with various information.

• 한국정보처리학회논문지
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• 제6권1호
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• pp.49-56
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• 1999

Distributed object Computing, owing to the development of distributed computing, has improved the performance of distributed processing conducted between homogeneous and heterogeneous systems in network. However, it has failed to solve fundamental problems such as network overload and enormous requests demands by servers and clients. In this paper, we propose to design and implement an Object Migration system that uses the java language to tackle the mentioned problems. As the first step of the implementation of the system, we justify the characteristics of t도 mobile object model that keeps codes and states of an object. Implemented Object Migration System would accept objects being migrated to a specific node and support the virtual place in which objects could be executed automatically. Therefore, the Object Migration system we suggest could not only solve problems imposed to traditional distributed computing but also offer transparency of object migration between homogeneous and heterogeneous systems.

• 한국CDE학회논문집
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• 제5권1호
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• pp.61-70
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• 2000

The design and development of a Web-based Workflow Management System (WfMS) is described in this paper. WfMSs are employed by many organizations to manage their business processes efficiently. The goal of this research is to provide an effective management of design processes in a distributed and heterogeneous environment-an environment in which workflow participants are geographically dispersed and use different computing platforms. We identify the requirements of WfMSs for the distributed and heterogeneous environment. We present an approach to applying the Web technology to was. The developed system is composed of three main modules: Worflow Engine, Web-based clients, and Process Designer. The workflow engine is implemented in pure Java for portability to heterogeneous platforms. furthermore, the client interfaces are all programmed using applets, and thus they can be readily accessed through the Internet/intranet. The Process Designer provides a build-time function of generating process specifications. Some important functions of the developed system are explained in this paper. A prototype system has been developed and applied to design processes. The system allows effective cooperation among designers who may be geographically separated.

• ETRI Journal
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• 제42권2호
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• pp.175-185
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• 2020

Inter-cell interference (ICI) is a major problem in heterogeneous networks, such as two-tier femtocell (FC) networks, because it leads to poor cell-edge throughput and system capacity. Dynamic ICI coordination (ICIC) schemes, which do not require prior frequency planning, must be employed for interference avoidance in such networks. In contrast to existing dynamic ICIC schemes that focus on homogeneous network scenarios, we propose a novel semi-distributed dynamic ICIC scheme to mitigate interference in heterogeneous network scenarios. With the goal of maximizing the utility of individual users, two separate algorithms, namely the FC base station (FBS)-level algorithm and FC management system (FMS)-level algorithm, are employed to restrict resource usage by dominant interference-creating cells. The distributed functionality of the FBS-level algorithm and low computational complexity of the FMS-level algorithm are the main advantages of the proposed scheme. Simulation results demonstrate improvement in cell-edge performance with no impact on system capacity or user fairness, which confirms the effectiveness of the proposed scheme compared to static and semi-static ICIC schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5446-5463
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• 2019

Parallel computing system components should be harmonized, and this harmonization is kept existent using synchronization time. Synchronization time affects the system in two ways. First, if we have too little synchronization time, some tasks face the problem of harmonization, as they need appropriate time to update and synchronize with the system. Second, if we allocate a large amount of time, stall system created. Random allocation of synchronization time for parallel systems slows down not only the booting time of the system but also the execution time of each application involved in the system. This paper presents a simulator used to test and allocate appropriate synchronization time for distributed and parallel heterogeneous systems. The simulator creates the parallel and heterogeneous system to be evaluated, and lets the user vary the synchronization time to optimize the booting time. NS3-cGEM5 simulator in this paper is formed by HLA-RTI federation integration of the two independent architecture and network simulators - NS3 and cGEM5. Therefore, nodes created on these simulators need synchronizations for harmonized system performance. We tested and allocated the appropriate synchronization time for our sample parallel system composed of one x86 server and three ARM clients.

• 컴퓨터교육학회논문지
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• 제9권1호
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• pp.107-118
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• 2006

부하재분배 방법은 컴퓨터시스템에서 중요한 요소이다. 수신자 개시 부하재분배 알고리즘에서는 전체 시스템이 저부하일 때 수신자(저부하 프로세서)가 부하를 이전받기 위해 송신자(과부하 프로세서)를 발견할 때까지 불필요한 이전 요청 메시지를 계속 보내게 된다. 따라서 이같은 상황에서는 과부하 상태인 송신자 프로세서로부터 승인 메시지를 받기까지 불필요한 프로세서간 통신으로 인하여 프로세서의 이용률이 저하되고, 타스크 처리율이 낮아지는 문제점이 발생한다. 본 논문에서는 유전알고리즘을 기반으로 하여 자기조절 능력을 포함하도록 한 이질형 분산 시스템에서의 동적 부하재분배 접근 방법을 제안한다. 이 기법에서는 불필요한 요청 메시지를 줄이기 위해 요청 메시지가 전송될 프로세서들이 제안된 유전 알고리즘에 의해 결정된다.

• 한국시뮬레이션학회논문지
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• 제8권4호
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• pp.9-24
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• 1999

We describe a heterogeneous simulation framework, so called DEVS-HLA, in which conventional simulation models and the DEVS (Discrete Event System Specification) models are interoperable. DEVS-HLA conceptually consists of three layers: model layer, DEVS BUS layer, and HLA (High Level Architecture) layer. The model layer has a collection of heterogeneous simulation models, such as DEVS, CSIM, SLAM, and so on, to represent various aspects of a complex system. The DEVS BUS layer provides a virtual software bus, DEVS BUS, so that such simulation models can communicate with each other. Finally, the HLA layer is employed as a communication infrastructure, which supports several good features for distributed simulation. The DEVS BUS has been implemented on the HLA/RTI (Run-Time Infrastructure) and a simple example of a flexible manufacturing system has been developed to validate the DEVS-HLA.