• Journal of KIISE:Computing Practices and Letters
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• v.10 no.1
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• pp.75-88
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• 2004

Condor is a distributed batch system for sharing the workload among the computers connected by a network. Condor distributed system was developed on the basis that every machine in a Condor pool is always connected by a network to run a Condor Job. Due to advances in wireless communication and mobile computing technology, conventional distributed computer systems can now include “mobile” clients as well as “fixed” clients. Moreover, mobile users want to lower their power consumption by off-loading potentially power and resource consuming jobs. In this paper, we describe the design and implementation of mobile interface for mobile clients in Condor distributed batch system. The main purpose of this work is to enable users on mobile computers to interact with Condor environment any time anywhere regardless of their connection to a Condor pool. The mobile Condor distributed system also aims to provide mobile users the same Condor services without making any significant changes to the existing Condor system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.193-196
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• 1997

A mobile computing environment has many difference in character from conventional communication over wired network. These include very presents distributed design system based the mobile agent for mobile computing environment. To integrate design resource, we presented ISA(Integration Service Agent, which allows a designer to build integrated application using distributed resources, and to collaborative by exchanging service. Also we propose ICM(XML based Intelligent Connection Manger) using mobile agent. And suggested new intelligent data and process transfer architecture using ICM to implement an agent based design system in mobile environment.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.1
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• pp.29-33
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• 2004

I propose a personalized digital library system (PDLS) based on an advanced distributed agent platform. The new platform is developed by improving the DECAF (Distributed Environment-Centered Agent Framework) which is one of the conventional distributed agent development toolkits. Also, a mobile ORB (Object Request Broker), Voyager, and a new multi agent negotiation algorithm are adopted to develop the advanced platform. The new platform is for mobile multi agents as well as the distributed environment, whereas the DECAF is for the distributed and non-mobile environment. From the results of the simulation the searched time of PDLS is lower, as the numbers of servers and agents are increased. And the user satisfaction is four times greater than the conventional client-server model. Therefore, the new platform has some optimality and higher performance in the distributed mobile environment.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.268-271
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• 2003

In this paper, we propose a new framework based on negotiatory mobile multi agent system, and implement a mobile multi agent environment based on DECAF(Distributed Environment-Centered Agent Framework) which is one of the distributed agent development toolkit so as to implement a new PDS(Personal Digital Library System). The new framework has some optimality and higher performance in distributed environments.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1206-1216
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• 1999

이동 호스트란 시간과 공간의 제약 없이 필요한 기능을 수행하고, 또한 원하는 정보에 접근할 수 있는 휴대용 컴퓨터를 일컫는다. 이동 컴퓨팅 환경이란 이러한 이동 호스트들을 지원할 수 있도록 구성된 분산 환경이다. 따라서 이동 컴퓨팅 환경에서의 분산 알고리즘은 정적 호스트만을 고려한 기존의 분산 환경에서와는 다르게 이동 호스트의 여러 가지 특성들을 고려하여 제안되어야 한다. 즉, 이동 컴퓨팅 환경의 도래로 인하여 이동성과 휴대성, 그리고 무선 통신과 같은 특성들을 고려한 새로운 분산 상호 배제 알고리즘이 필요하다. 이제까지 이동 컴퓨팅 환경에서의 상호 배제 알고리즘은 토큰 링 구조에 기반을 두고 설계되었다. 토큰 링 구조는 이동 호스트들의 위치를 유지하기 위하여 높은 비용을 필요로 하는 단점을 가지고 있다. 본 논문에서는 균형 높이 트리(height-balanced tree)라는 새로운 모형을 제안함으로써 정적 분산 환경과 이동 분산 환경이 혼합된 환경에서 상호 배제 비용을 감소시킬 수 있는 새로운 알고리즘을 제안하며, 각 경우에 있어서의 비용을 산출하고 평가한다.Abstract The mobile host is a potable computer that carries out necessary functions and has the ability to access desirable informations without any constraints in time and space. Mobile computing environment is a distributed environment that is organized to support such mobile hosts. In that environment, distributed algorithms of which environment not only with static hosts but with mobile host's several properties should be proposed. With the emergence of mobile computing environments, a new distributed mutual exclusion method should be required to consider properties mobile computing system such as mobility, portability, and wireless communication. Until now, distributed mutual exclusion methods for mobile computing environments are designed based on a token ring structure, which have the drawbacks of requiring high costs in order to locate mobile hosts. In this paper, we propose a distributed mutual exclusion method that can reduce such costs by structuring the entire system as a height-balanced tree for static distributed networks and for networks with mobile hosts. We evaluated the operation costs in each case.

• Journal of the Korea Society of Computer and Information
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• v.21 no.8
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• pp.41-48
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• 2016

In this paper, we propose an election protocol based on mobile ad-hoc network. In distributed systems, a group of computer should continue to do cooperation in order to finish some jobs. In such a system, an election protocol is especially practical and important elements to provide processes in a group with a consistent common knowledge about the membership of the group. Whenever a membership change occurs, processes should agree on which of them should do to accomplish an unfinished job or begins a new job. The problem of electing a leader is very same with the agreeing common predicate in a distributed system such as the consensus problem. Based on the termination detection protocol that is traditional one in asynchronous distributed systems, we present the new election protocol in distributed systems that are based on MANET, i.e. mobile ad hoc network.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.491-494
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• 1998

This paper describes the design and implementation of file system which allows the collaborative computing in mobile environment. The design goal is to make a logically one file system in the distributed computer systems. The characteristics of frequent, foreseeable and variable disconnections in a mobile environment wrer taken into consideration. We introduce an auto-hoarding system that provides the availability of large number of nodes which are weakly and intermittently connected. The data consistency problems in distributed or replicated mobile data are also discussed.

• Journal of KIISE:Software and Applications
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• v.29 no.1_2
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• pp.30-41
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• 2002

We focus on the mobile agents which are considered as new paradigm to solve information retrieval of large volumes of data in the distributed and heterogeneous environment. The mobile agent moves the computation to data instead of large volumes of data to computations. In this paper, we propose an information retrieval model, which can effectively search data in the distributed and heterogeneous environment, using mobile agents. Our model is applied to the design and implementation of an Q&A(Question and Answer) retrieval system. Our Q&A retrieval system, called QASSMA(Q&A Search System using Mobile Agents), uses mobile agents to retrieve articles from Q&A boards and newsgroups that exist in the heterogeneous and distributed environment. QASSMA has the following features and advantages. First, the mobile retrieval agent moves to the destination server to retrieve articles to reduce the retrieval time by eliminating data traffics from the server to the client host. Also it can reduce the traffic that was occurred in the centralized network system, and reduce the usage of resources by sending its agent and running in the destination host. Finally, the mobile retrieval agent of QASSMA can add and update dynamically the class file according to its retrieval environment, and support other retrieval manner. In this paper, we have shown that our Q&A retrieval system using mobile agents is more efficient than the retrieval system using static agents by our experiments.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.132-137
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• 2003

Due to the advances of the Internet technologies and web-based applications, the demand for wide distributed processing is increased. Mobile Agents have been proposed as a model to meet with the requirement for such environment. But current mobile agent system has the technical restriction. The requirement of mobile agent for the wide distributed processing is analysed in mobile agent system architecture, programming paradigm and technologies.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.581-588
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• 2005

The performance of mobile devices and wireless networks is improved rapidly and Mobility management skills such as Mobile IP and ad-hoc technology were developed. So the requirement of processing the distributed computing is highly increased in any place and any time or in the state of movement. Therefore we studied the mobile grid system to process the distributed applications properly in wireless networks. In addition to typical computational resources, Mobile Grid brings new resources such as sensor, mobile devices or other wireless devices to distributed computing for the purpose of resource-sharing. In this paper, we design and implement the mobile grid system in wireless lan network environment for the providing the grid service. Also, we evaluate the performance of mobile grid system using the processing the distributed applications in implemented mobile grid environments.