• The Korean Publising Journal, Monthly
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• s.340
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• pp.20-21
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• 2004

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.211-213
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• 2002

TCP Vegas는 TCP Reno에 비해 효율성과 안전성 측면에서 보다 나은 성능을 보이고 있으나, 두 버전이 같이 사용되는 경우 충분한 성능을 발휘하지 못하여 공정성에 문제점을 드러내고 있다. 본 논문에서는 TCP Vegas의 알고리즘에서 사용하는 상수 요소인 $\alpha$, $\beta$ 값의 변화에 의해 TCP Reno 버전과의 공정성이 향상되는 사실을 시뮬레이션을 통해 확인하였으며, 이에 따른 향후 연구과제를 제시하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.259-261
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• 2005

현재 이동성을 지원하는 Mobile IPv4와 Mobile IPv6 프로토콜은 서로 다른 버전의 네트워크에서는 호환이 불가능하게 설계되어있다. Mobile IPv6 프로토콜에서 확장되어 네트워크 이동성까지 지원되는 Network Mobility(NEMO) 프로토콜 역시 IPv6 네트워크 내에서만 이동성이 보장된다. 그러나 앞으로의 인터넷은 IPv4와 IPv6 네트워크가 상당기간 공존할 것으로 예상되기 때문에 두 버전의 네트워크 사이에 이동성이 자연스럽게 지원되는 방안이 필요하다. 따라서 본 논문에서는 다른 버전의 네트워크 사이에 NEMO 프로토콜에 대해 이동성을 지원하기 위한 방법을 제안한다. 우리는 Mobile Router(MR)가 IPv4 네트워크로 이동을 한 경우에도 Tunnel Agent(TA)를 통해 NEMO Tunnel을 유지함으로써 이동성을 관리할 수 있는 새로운 메커니즘을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1165-1168
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• 2005

현재 이동성을 지원하는 Mobile IPv4 와 Mobile IPv6 프로토콜은 서로 다른 버전의 네트워크에서는 호환이 불가능하게 설계되어있다. Mobile IPv6 프로토콜에서 확장되어 네트워크 이동성까지 지원되는 Network Mobility(NEMO) 프로토콜 역시 IPv6 네트워크 내에서만 이동성이 보장된다. 그러나 앞으로의 인터넷은 IPv4 와 IPv6 네트워크가 상당기간 공존할 것으로 예상되기 때문에 두 버전의 네트워크 사이에 이동성이 자연스럽게 지원되는 방안이 필요하다. 따라서 본 논문에서는 다른 버전의 네트워크 사이에 NEMO 프로토콜에 대해 이동성을 지원하기 위한 방법을 제안한다. 우리는 Mobile Router(MR)가 IPv4 네트워크로 이동을 한 경우에도 Tunnel Agent(TA)를 통해 NEMO 터널을 유지함으로써 이동성을 관리할 수 있는 새로운 메커니즘을 제시한다.

• Korean Journal of Logic
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• v.18 no.3
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• pp.437-456
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• 2015

This paper deals with Routley-Meyer semantics for two versions of R of Relevance. For this, first, we introduce two systems $R^t$, $R^T$ and their corresponding algebraic semantics. We next consider Routley-Meyer semantics for these systems.

• The Journal of Engineering Research
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• v.2 no.1
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• pp.23-30
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• 1997

For a effective management and easy tool integration of CAD database, Hierarchy interface System(HIS) was designed and GROCO(Graph Representation fOr Complex Objects) Model was presented in another my paper[10]. Hierarchy Interface System which is composed of two subsystems of a configurator and a converter is designed for the interface between a conventional database management system and CAD tools. In this paper, Version Management System is presented for supporting effective operations of HIS using GROCO model. Version Management System supports efficiently CAD database charaters having a hierarchical structure of composite objects. In Version Management System, A design evolves in discrete states through mutation and derivation for going phases of design giving rise to multiple versions. Operations and rules are provided transition between their different states. and for controlling update propagation and preventing version proliferation. Version Modeling Graph is proposed for dealing with versioning at the instance and type levels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.233-241
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• 2010

CoSlide is a collaborative system, extending the Jakarta Slide WebDAV server. The CoSlide server provides group workspaces for collaborators. CoSpace is a client which supports various collaborative authoring activities on the CoSlide server through the WebDAV protocol. CoSpace provides graphic user interfaces to support effective interaction among the collaborators, managing the shared resources for them. However, during collaboration, simultaneous modifications on the content of shared resources might cause conflicts among the content of the revisions made by the collaborators, leading to serious problems on project progress. In this paper, we describe an extension of the CoSpace client to solve the problem. The extended CoSpace client supports the remote version management facility through which the collaborators can manage the versions of the associated server resources in the distance. Also, to identify the changes of the text files such as program source codes, the extended client provides the facility for comparing two versions and displaying the differences in a visual manner. In addition, it provides the version management of a whole workspace and the removal of all the unnecessary versions of the designated resources.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.9-21
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• 1999

This paper presents the time-segmented storage structure in order to increment search performance and the two data migration strategies: migration by Time Granularity and migration by LST-GET. In the migration strategy by Time Granularity, we describe how to assign entity version to the past, current segment, and future segments. We also describe searching and moving processes for data validity at a granularity level. In the migration strategy by LST-GET, we describe how to computer the value of dividing criterion. We simulate the search performance of the proposed segmented storage structure in comparison with the conventional storage structure in comparison with the conventional storage structure in relational database system. Finally, extensive simulation studies are performed in order to compare the search performance of the migration strategies with the time-segmented storage structure.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.3
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• pp.140-148
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• 2009

Recent advances in communication and multimedia technologies make it possible to provide video-on-demand(VOD) services and people can access video servers over the Internet at any time using their electronic devices, such as PDA, mobile phone and digital TV. Each device has different processing capabilities, energy budgets, display sizes and network connectivities. To support such diverse devices, multiple versions of videos are needed to meet users' requests. In general cases, VOD servers cannot store all the versions of videos due to the storage limitation. When a device requests a stored version, the server can send the appropriate version immediately, but when the requested version is not stored, the server first converts some stored version to the requested version, and then sends it to the client. We call this conversion process transcoding. If transcoding occurs frequently in a VOD server, the CPU resource of the server becomes insufficient to response to clients. Thus, to admit as many requests as possible, we need to maximize the CPU availability. In this paper, we propose a new algorithm to select versions from those stored on disk using a branch and bound technique to maximize the CPU availability. We also explore the impact of these storage management policies on streaming to heterogeneous users.

• Journal of KIISE:Databases
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• v.31 no.5
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• pp.457-467
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• 2004

The efficiency of algorithms managing data caches has a major impact on the performance of systems that utilize client-side data caching. In these systems, two versions of data can be maintained without an additional space overhead of the server by exploiting the replication of data in the server's buffer and clients' caches. In this paper, we present a new cache consistency algorithm employing versions: Two Versions-Callback Locking (2V-CBL). Our experimental results indicate that 2V-CBL provides good performance, particularly outperforms a leading cache consistency algorithm, Asynchronous Avoidance-based Gache Consistency, when some clients run only read-only transactions.