• 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.

• Journal of Communications and Networks
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• v.13 no.6
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• pp.591-601
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• 2011

Today's Internet which provides communication channels with best-effort end-to-end performance is rapidly evolving into an autonomic global computing platform. Achieving autonomicity in the Future Internet will require a performance architecture that (a) allows users to request and own 'slices' of geographically-distributed host and network resources, (b) measures and monitors end-to-end host and network status, (c) enables analysis of the measurements within expert systems, and (d) provides performance intelligence in a timely manner for application adaptations to improve performance and scalability. We describe the requirements and design of one such "Future Internet performance architecture" (FIPA), and present our reference implementation of FIPA called 'OnTimeMeasure.' OnTimeMeasure comprises of several measurement-related services that can interact with each other and with existing measurement frameworks to enable performance intelligence. We also explain our OnTimeMeasure deployment in the global environment for network innovations (GENI) infrastructure collaborative research initiative to build a sliceable Future Internet. Further, we present an applicationad-aptation case study in GENI that uses OnTimeMeasure-enabled performance intelligence in the context of dynamic resource allocation within thin-client based virtual desktop clouds. We show how a virtual desktop cloud provider in the Future Internet can use the performance intelligence to increase cloud scalability, while simultaneously delivering satisfactory user quality-of-experience.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.188-196
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• 2002

As networked virtual environment (NVE) scales in terms of users and network latency, a key aspect to consider is scalability for interactive performance because a large number of objects likely impose heavy burden especially on the network and computational resources. To improve the scalability, various relevance-filtering mechanism have been proposed. However, the existing filtering mechanism do not scale well in terms of interactive performance as the number of users increase and crowds in a specific place. In this paper, we propose a new scalable filtering scheme which reduces the number of messages by dynamically grouping users based on their interests and distance. Within a group, members communicate with each other with high fidelity. However, a representative sends up-to-dated group information of members with low transmission frequency when they are not of immediate interest but are still within the interest area. The representative is elected from members of the group in distributed manner. The proposed scheme enhances the interactive performance scalability of large-scale NVE systems as much as 18% compared with the existing approach.

• Journal of the Korean Geotechnical Society
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• v.38 no.2
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• pp.5-13
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• 2022

The unsaturated behavior of sandy silt (SM soil) was investigated experimentally. Special attention was given to the stress-strain behavior of unsaturated weathered soil (SM) prior to failure and behavior at failure under monotonic loading. A sandy silt (SM) weathered soil containing a certain amount of fine contents distributed in Korea, was chosen to form samples with different densities of Dr=25%, 60%, and 75%. and matric suctions. The isotopically Consolidated Drain test (CD-test) was performed to maintain a constant matric suction during the shearing process. Based on the experimental results, it was qualitatively identified that the higher the relative density, the greater the virtual friction angle (ϕ^b) value and AEV (Air Entry Value) were induced. Also it is found that the internal friction angle (ϕ') is more or less constant. even if the matric suction is increased.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.236-238
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• 1999

컴퓨팅 능력의 발달과 네트워크의 대용량화로 인해서 다중 참여자를 고려한 분산 가상 환경에 대한 연구가 활발하게 이루어지고 있다. 분산 가상 환경은 네트워크를 통해서 연결된 다중의 참여자를 고려해야 하기 때문에 참여자 그룹 관리가 필수적으로 요구된다. 기존의 분산 가상 환경에서의 참여자 그룹 관리는 참여자의 가입, 탈퇴 처리와 현재 상태의 제공 기능 등을 지원하고 있다. 그러나, 다양한 형태의 참여자 활동을 지원하기 위해서는 현재 상태의 정보 뿐만 아니라 다양한 그룹 활동의 지원과 각각의 참여자가 수행한 작업의 형태와 그룹에 대한 정책등에 대한 적절한 관리가 필요하다. 이러한 작업은 기존의 참여자 그룹 관리 방식에는 중앙 서버에 지나친 부담을 주기 때문에 이에 대한 해결하기 위한 고려도 필요하다. 이 논문에서는 모빌 에이전트를 기반한 분산 가상 환경을 위한 참여자 그룹 관리 시스템을 설계하였다. 설계한 시스템의 특징은 하나의 그룹내에 다수의 소그룹이 존재할 수 있게 함으로써 보다 다양한 그룹 활동을 지원하며, 그룹의 현재 상태 정보 뿐만 아니라 그룹에 참여하는 각각의 참여자들의 행위 정보와 이동 정보를 관리함으로써 참여자를 진단을 욕하는 응용에 사용될 수 있다. 또한, 모빌 에이전트 형태로 설계함으로써 중앙 서버에 대한 지나친 부담 문제를 해결하였다.

• Asian Journal of Innovation and Policy
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• v.4 no.3
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• pp.381-396
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• 2015

Cyberinfrastructure is a research infrastructure that provides an environment in which research communities can get access to distributed resources and collaborate at unprecedented levels of computation, storage, and network capacity. The Worldwide LHC Computing Grid (WLCG) is a global collaborative project of computing or data centers that enables access to scientific data generated by the Large Hadron Collider (LHC) experiments at CERN. This case study analyzes the WLCG as a model of cyberinfrastructure in research collaboration. WLCG provides a useful case of how cyberinfrastructure can work in providing an infrastructure for collaborative researches under data-intensive paradigm. Cyberinfrastructure plays the critical role of facilitating collaboration of diverse and widely separated communities of researchers. Data-intensive science requires new strategies for research support and significant development of cyberinfrastructure. The sustainability of WLCG depends on the resources of partner organizations and virtual organizations at international levels, essential for research collaboration.

• IE interfaces
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• v.13 no.3
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• pp.339-347
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• 2000

The use of the Web-based Simulation Environment (WBSE) provides a strong influence on supply chain simulations. A virtual supply chain simulation is available to evaluate strategies for reducing response time to customers and for shrinking the finished goods inventory along its supply chain. This paper presents the basic concepts and definitions of Web-Based Global Supply Chain Management (WBGSCM) simulation system. It also discusses the advantages of supply chain simulation modules integration. A Time Synchronization Mechanism (TSM) called Phased Bucket Scheme (PBS) is introduced as an approach of the distributed simulation modules integration.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.224-226
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• 2005

Grid computing enables the fundamental computing shift from a localized resource computing model to a fully-distributed virtual organization with shared resources. In the grid computing environment, grid users usually get access rights by mapping their credential to local account. The mapped total account is temporally belongs to grid user. So, data on the secondary storage, which is produced by grid operation, can increase the load of system administration or can issue grid user's privacy. In this paper, we design a data management system for grid user to cover these problems. This system implements template account mechanism and manages local grid data.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.945-948
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• 2005

그리드 정보검색 시스템은 일반적인 정보검색 시스템의 문제점과 한계점을 인식하고, 그리드라는 분산처리 환경을 기반으로 정보검색 시스템을 구축함으로써 보다 효율적이고 유연한 확장성을 갖는 정보검색 서비스를 제공한다. 본 논문에서는 그리드 시스템 환경에 맞게 그리드 미들웨어 중에 하나인 글로버스 툴킷(Globus Toolkit)을 이용하여 정보검색을 위한 가상 조직(VO: Virtual Organization)을 구성했다. 그리고 그리드 정보검색을 위한 전단계로 웹상에서 각종 정보를 수집하는 P2P 기반 분산 크롤러들을 관리하는 크롤러 매니저를 그리드 서비스로 설계 및 구현하여 그리드 정보검색 시스템에 존재하는 다른 서비스들과 함께 활용할 수 있도록 하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.7
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• pp.317-330
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• 2001

대규모 가상환경의 핵심은 사용자 PC의 성능에 영향을 받는 확장성에 있다. 기존의 접근 방식은 대규모 환경을 지원하기 위해 멀티캐스트를 주로 사용하였다. 그러나 멀티캐스트는 현재 멀티캐스트 하드웨어가 지원할 수 있는 그룹의 수가 제한된다는 문제점이 있다. 본 논문에서는 PC 클라이언트와 인터넷과 같은 대규모 네트워크 기반의 확장성 높은 가상환경 모델을 제시한다. 멀티캐스트 네트워크와 PC 클라이언트 사이에 위치하는 관심영역 관리자(AOIM)는 멀티캐스트 그룹과 함께 다중 필터링을 수행하여 정보의 흐름을 최적화한다. 또한, 관심영역 관리자는 사용자의 관심 패턴에 따라 관심영역(AOI)으로부터 PC 클라이언트로의 데이터 전송량을 조절한다. 관심영역은 정보의 정확도에 따라 세 단계로 구분되며, 각 단계의 구분은 네트워크 현황에 따라 적응적으로 수축 또는 확장될 수 있어 PC 클라이언트는 최적화된 가상환경 상태정보를 제공받는다. 결론적으로, 제안된 모델은 다양한 컴퓨팅 환경의 PC 클라이언트에게 정확한 최우선 관심영역 정보를 제공한다.