• Journal of Korea Multimedia Society
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• v.9 no.7
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• pp.827-834
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• 2006

In distributed virtual environment, system response time to users' interactions is an importance factor to determine the degree of contentment with the system. Generally, response time is affected by the efficiency of event message processing algorithm, and most of previous systems use FCFS algorithm, which processes message traffic sequentially based only on the event occurrence time. Since this method totally depends on the order of occurrence without considering the priorities of events, it has a problem that might drop the degree of system response time by causing to delay processing message traffic when a bottleneck phenomenon happens in the server side. To overcome this limitation of FCFS algorithm, this paper proposes a concurrent event scheduling algorithm, which is able to process event messages concurrently by assigning the priorities to the events. It is also able to satisfy the two goals of system together, consistency and responsiveness through the combination of occurrence time with priority concept of events.

• Journal of Korea Multimedia Society
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• v.9 no.2
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• pp.189-196
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• 2006

This paper proposes a priority based AOI management model as a method to effectively process message traffic for collaboration in virtual environments. Where message traffic reaches the maximum capacity of the message replay server in DVE, some of the events might be delayed to be updated at the remote clients. Because existing AOI models depend only on the occurrence time of events, they have a problem that more important events in the context might be processed later than less serious ones. Close Interactions with other participants are relatively more important than simple events which happen at a distance from the participant. This study classifies the priorities of events according to the degree of interest, and proposes a method to reduce processing delay time of events highly interested by a user. The proposed model offers a way to effectively utilize limited capacity of a server using a priority queue mechanism, which is able to handle different kinds of events. To prevent from starvation of simple events and to give fairness to the proposed algorithm, event occurrence time is also considered as well as degree of interest when processing events.

• ETRI Journal
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• v.24 no.6
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• pp.465-468
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• 2002

Ethernet passive optical networks (PONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and a customer site. In this paper, we propose a new algorithm of dynamic bandwidth allocation for multimedia services over Ethernet PONs. To implement the suggested dynamic bandwidth allocation algorithm, we present control message formats that handle classified bandwidths in a multi-point control protocol of Ethernet PONs.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.315-320
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• 2001

최근 인터넷을 기반으로 하는 정보통신 인프라의 발달에 따라 다양한 서비스가 등장하였으며 이들 서비스들을 통합하여 제공하는 인스턴트 메시징 서비스가 등장하여 그 수요가 급증하고 있다. 그러나, 기존의 인스턴트 메시징 서비스들은 전송되는 메시지에 대하여 어떠한 보안장치도 제공되지 않아서 제 3자에 의한 개인정보 유출 및 차용이 문제점으로 부각되고 있다. 따라서 본 논문에서는 기존의 인스턴트 메시징 구조에 사용자 인증 기능 및 암호화 기능을 조합하여 안전한 메시지 전송을 위한 SMS(Secure Messenger System)를 설계하고 개발하였다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.649-654
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• 2002

현재 많은 기업들은 수년에 걸쳐 많은 자원과 시간을 투자하여 JAVA, CORBA, COM 등을 이용해 기업시스템을 개발 해왔다. 이렇게 많은 기업들이 서로 다른 분산 컴퓨팅 기술을 가지고 개발해온 기업 시스템의 통합이 절실히 필요하게 되었다. SOAP은 JAVA, CORBA, COM 등의 분산 객체 기술에 구애받지 않는 프로토콜이며, 심지어 이들 분산 객체 기술을 전혀 사용하지 않는 애플리케이션도 SOAP을 통해 원격 프로시져 호출이나 데이터 전송을 수행할 수 있다. 본 논문에서는 이러한 SOAP의 특징을 이용한 클라이언트/서버간 메시지 전송 시스템을 구현하였다.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.231-234
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• 2002

This paper has studied a management system for RCST of the Satellite Multimedia Internet Service through analysing the architecture and specification of BSAN based on Digital Video Broadcasting System. In this paper, designing and implementing RCST DPM and agent system are shown. The UCD-SNMP framework served as base station for implementation of the agent. And the message protocol between RCST DPM and agent system has been also defined to provide a way for interaction.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.7-10
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• 2008

본 논문은 멀티에이전트 환경에서 에이전트간의 지식 이종성과 통신 가능성 분산 제어의 방법에 중점을 두고 협동을 위한 정보를 KQML을 통하여 메시지를 전달한다. 항공사, 숙박업소, 설명 정보를 제공하는 에이전트들로 구성하여 조정 에이전트로 하여금 다른 에이전트가 필요한 정보를 주는 투어 스케줄링 에이전트 시스템을 구현하여 여행 준비자들이 자유 투어 스케줄링을 계획하는데 필요한 정보를 제공하는 것을 목적으로 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2169-2175
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• 2014

In this paper we have proposed a new distributed architecture of session-based instant message system, in which multiple servers can distribute loads effectively to improve system extendability. The server of session-based instant message system should manage SIP sessions to transfer instant message with multimedia data to each users, and it should process large amount of presence informations from each users. Therefore load of the server should be distributed as the number of users increases. In our system, when server load increases according to large user numbers, the load are distributed by selecting a server with the lowest load value, or new server is created to allocate the message processing. Therefore the overall load of instant message system can be dynamically distributed. A new presence information data format with added elements for controlling server load has been designed for this purpose, and SIP messages exchanging procedure between servers and users has been also suggested. The performance of our proposed system has been analysed by simulation, and showed improvement of performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.9
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• pp.1700-1709
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• 2006

In this raper we researched on the development methods and design of the B-ISDN protocol embedded IP-PBX System with the computers interconnected by the Internet for the previous telephone exchange and communication. We designed the structure of the user terminal and exchange sewer of the IP-PBX System, defined message and data structure for call control, and designed call control state transition and call control message flows for user's communication. And we researched on the message flows for supplementary services and the call control for multiple calls.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.79-84
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• 2016

In this paper, we propose reliable message transmission scheme based on CoAP, considering the constrained feature of IoT device, such as low power, the limited memory size and low computing capacity. Recently, the various kinds of application protocol has been studied to support IoT environments. In particular, CoAP protocol was developed as application protocol for IoT at the IETF core WG. However, because CoAP protocol is deigned to be used in constrained node, this protocol uses UDP at transport layer. Thus, data loss may occur frequently in network congestion environments. The proposed scheme, in this paper, is to overcome the problem of frequent data loss with low overhead. Also it includes the function which is to minimize the data loss in sleep mode of IoT device.