• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1621-1630
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• 2009

There is a lot of recent research to provide services of dynamic distributed contents in P2P-based distributed environment. Distributed services of contents objects, however, have problems in QoS and dynamic management of segments. This paper proposed a new segment management method for the service of P2P-based distributed contents. The proposed method manages groups by the SGM(Segment Group Manager). The SGM manages streaming efficiently by the grouping of segments to be served in P2P environment. The segments in the same group cooperate for improved QoS using the management structure based on the distance and relationship. The distance-based management structure is for the improvement of retrieval efficiency while the relationship-based management structure is for the improvement of service ratio. The simulation results of the proposed method showed improvements in average transmission efficiency and average service rate. The improvement is 8% - 30% in average transmission efficiency and 10% - 30% in average service rate.

• Annual Conference of KIPS
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• 2015.10a
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• pp.314-316
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• 2015

데이터 분배 서비스(DDS)는 객체 관리 그룹(OMG)에서 정의한 미들웨어 규격으로, 분산 네트워크 상에서 표준화 된 데이터 분배를 위한 응용프로그램 인터페이스(API)를 정의하고 있다. NeoDDS는 OMG DDS 규격을 준수하는 국산 DDS 미들웨어이다. 본 논문에서는 DDS 시스템의 개발 단계에서 DDS 시스템의 동작을 시뮬레이션 해 볼 수 있도록 지원하는 NeoDDS 기반의 시뮬레이터인 NeoSim의 구조와 동작방식에 대해 소개한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.394-396
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• 2002

'분산 모의훈련 전장환경'은 실제 또는 가상전쟁, 전투 등 군사 상황을 묘사하기 위해, 둘 또는 그 이상의 적대 세력간에 발생하는 군사적 상황을 게임규칙, 자료 및 절차를 사용하여 모의하는 군사작전 게임(war game)을 의미한다. 이는 컴퓨터와 네트워크를 이용한 '합성 가상 전장환경'에서 구현되는데, 특성상 다수의 게이머와 게이머, 게이머와 객체, 객체들간에 네트워크를 통한 빈번한 메시지 송.수신을 통한 정보를 교환하고 실시간으로 상호동작 한다. 즉, '합성 가상 전장환경'의 구현을 위해서는 신뢰성과 실시간성을 보장하는 다자간 통신의 보장이 핵심을 이룬다. 그러나, 일반 인터넷상의 브로드캐스팅 기술을 적용할 경우, 가상전장환경에서 폭주하는 통신량을 실시간으로 처리하기엔 어려운 문제점이 있다. 따라서 '합성 가상전장가상환경'의 보다 효과적인 구현을 위해서는 고신뢰 실시간 다중 그룹통신 기술의 개발이 요구된다. 본 논문은 그룹통신 개념에 기반하여 가상 합성 전장 환경에 적용할 수 있는 효율적인 전송 서비스를 위한 네 가지 전송 알고리즘을 제시하며, API 설계를 통해 서비스를 구현한다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06b
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• pp.318-323
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• 2010

최근 병원이 주체가 되어 유비쿼터스 인프라를 구축하여, 이를 기반으로 병원 구성원뿐만 아니라 환자에 이르기까지 다양한 병원 정보 서비스를 제공하기 위한 연구와 시범사업이 이루어지고 있는 추세이다. 본 논문에서는 u-병원 환경에서 위치기반 가이드 시스템을 제안한다. 제한한 시스템의 소프트웨어 구조는 기존 연구되었던 분산객체그룹프레임워크(Distributed Object Group Framework)와 JADE(Java Agent DEvelopment Framework)를 기반으로 한다. 특히, RFID를 이용한 실내 위치 추적 기술과 본 연구실에서 연구해온 분산 프레임워크를 바탕으로 병원을 대상으로 하여 환자의 위치에 따르는 각 검사실의 위치와 검사에 필요한 정보를 제공한다. 이를 위해 시스템을 구성하는 전체 시스템 구조와 구성요소 간 상호작용에 대해 기술하였다. 그리고 물리적인 환경을 보이고 시스템의 수행과정을 모바일 디바이스상의 사용자 GUI를 통해 보였다.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.85-97
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• 2005

In this paper, we construct the traffic information database by using the acquired data from the traffic information devices installed in road network, and, by referring to this database, propose the intersection simulation system which can dynamically manage the real-time traffic flow for each section of road from the intersections, This system consists of hierarchical 3 parts, The lower layer is the physical layer where the traffic information is acquired on an actual road. The traffic flow control framework exists in the middle layer. The framework supports the grouping of intersection, the collection of real-time traffic flow information, and the remote monitoring and control by using the traffic information of the lower layer, This layer is designed by extending the distributed object group framework we developed. In upper layer, the intersection simulator applications controlling the traffic flow by grouping the intersections exist. The components of the intersection application in our system are composed of the implementing objects based on the Time-triggered Message-triggered Object(TMO) scheme, The intersection simulation system considers the each intersection on road as an application group, and can apply the control models of dynamic traffic flow by the road's status. At this time, we use the real-time traffic information collected through inter-communication among intersections. For constructing this system, we defined the system architecture and the interaction of components on the traffic flow control framework which supports the TMO scheme and the TMO Support Middleware(TMOSM), and designed the application simulator and the user interface to the monitoring and the controlling of traffic flow.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.66-77
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• 2006

In this paper, we researched the searching and tracking locations of a home resident using ON/OFF switches and sensors and designed a remote monitoring system. As an implementation environment, this system is developed on the base of the distributed object group framework we have developed from previous works. In order to trace the moving locations of a home resident, we firstly showed a home structure which attaches ON/OFF switches and sensors to home appliances and indoor facilities being fixed in home. Whenever a home resident opens/closes these objects, the signals operated from ON/OFF switches and sensors are sent to a home server system. In this time, the real locations of ON/OFF switches and sensors that the signals are being occurred must be the current location that he/she stays. A home server system provides the functionalities that map the real location of a resident in home to virtual location designed on remote desk-tops or terminals like PDAs, and that construct a healthcare database consisted of moving patterns, moving ranges, momentum for analyzing the given searching locations and times Finally, this system provides these information for remotely monitoring services.

• The KIPS Transactions:PartA
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• v.10A no.5
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• pp.439-452
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• 2003

Mobile agent is one of the good technologies for overcoming network load and latency in distributed applications, and it may be a promising way of base technology of distributed applications because of its high adaptability for various network environments. In this paper, a mobile agent programming system, called HUMAN, is designed and implemented efficient use in various distributed applications based on mobile agents. HUMAN supports such high level utilities as file searhing, addressing by groups of nodes, storing path information, storing search information, and thus it gives us high easiness in agent-based programming. And it provides various itinerary modes and flexible reply modes for easy adaptation to given network environment. It also provides a management server for registering and active agents. Thus it can be efficiently applied for such varous distributed applications as searching distributed information, remote control, and file sharing in networks. A simple electronic commerce system is designed is designed and implemented as a HUMAN based illustrative application.

• The Journal of the Korea Contents Association
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• v.6 no.12
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• pp.50-58
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• 2006

The mutual exclusion (MX) paradigm can be used as a building block in many practical problems such as group communication, atomic commitment and replicated data management where the exclusive use of an object might be useful. The problem has been widely studied in the research community since one reason for this wide interest is that many distributed protocols need a mutual exclusion protocol. However, despite its usefulness, to our knowledge there is no work that has been devoted to this problem in a mobile computing environment. In this paper, we describe a solution to the mutual exclusion problem from mobile computing systems. This solution is based on the token-based mutual exclusion algorithm.

• The Journal of the Korea Contents Association
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• v.6 no.1
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• pp.72-79
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• 2006

Recently, a MMORPG(Massively Multi-play Online Role Playing Game) has built distribute server by Seamless world. This paper proposes an efficient collision detection method. DLS is used to dynamically adjust spatial subdivisions in each the boundary regions of distribute server We use an index table to effectively utilize the relationships between in the nodes and can perform the collision detection efficiently by reconstructing nodes of the tree. Also, we maintain the information for the boundary region to efficiently detect the collections and adjust the boundary regions between distributed servers by using DLS. As the DLS uses pointers, the information for each server is not needed and the boundary regions between the distributed servers are efficiently searched. Using node index points, the construction table can be made to find between ray and neighborhood node, In addition, processes for Network traffic reduce because a copy of the boundary regions is not needed when a object moves with realtime.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2258-2270
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• 1998

Recently, the distributed processing environments provide various open multimedia serivces through telecommunication network and have been developing into information networking structure based on object oriented concepts and distributed systems which can apply new services with a few changes the existing networks. This paper proposes the object group model which is the collection of objects and can functionally and efficiently manage the individual object. this paper presents the analysis of the requirement and the function specifications to propose the object group model, and depicts the functional structure in details using its analysis. The goal of this paper is to decrease the complexity of the object's management and to voercome the limitations of among the components of object group for management and service functions based on our proposed the object group model and show interaction procedures to eTD (event tracing diagram)s and finally we design the object group model by TINA-ODL.