• The Journal of the Korea Contents Association
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• v.6 no.3
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• pp.46-54
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• 2006

Various schemes for mobility are currently studied in ITU-T, 3GPP, IETF, and so on. Mobility support in NGN for seamless service is necessarily required. Currently proposed mechanisms are MIPV6,0, Q.MMF, and IMS. However the performance comparison of all existing schemes is not examined as yet. That is, the existing methods need to be compared according to each performance parameter. So, in this paper, we investigate and compare the performances of MIPv6,0, Q.MMF, IMS to location registration. In addition, this paper presents the performance comparison of handover latency times. For this, we use NS-2 simulator. As a result of analysis, Q.MMF shown the best performance as it is measured the minimum time and cost. And it has low handover latency time in comparison with other mechanisms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.63-70
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• 2005

Various schemes for mobility are currently studied in ITU-T, 3GPP, IETF, and so on. Mobility support in NGN for seamless service is necessarily required. Currently proposed mechanisms are MIPv6, $IP^2$, and Q.MMF. However the performance comparison of all existing schemes is not examined as yet. That is, the existing methods need to be compared according to each performance parameter. So, in this paper, we investigate and compare the performances of MIPv6, $IP^2$, Q.MMF to location registration. In addition, this paper presents the performance comparison of handover latency times. For this, we use NS-2 simulator. As a result of analysis, $IP^2$ shown the best performance as it is measured the minimum time and cost. And it has low handover latency time in comparison with other mechanisms.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.48-64
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• 2003

Recently, as the number of mobile users keeps increasing explosively, the location management to track the mobile users in mobile communication systems is being more important. However, the previous location management schemes have been used static location information without the consideration of a user's moving direction. This results in unnecessary pagings, consequently it increases location management costs. In this paper, we propose a mew location management costs. In this paper, we propose a new location the cell occurred a location update. It also determines whether the location update will be executed or not, by the offset operation of direction vector. Thus, a user's paging areas are generated dynamically along the user's moving direction. The wide of paging areas is also determined dynamically. Besides, we present analytic model for our scheme. To compare with our scheme, the distance-based scheme is analyzed. The numerical result shows that our scheme is more efficient than the distance-based scheme in the most cases except a low CMR. Particularly if a user move into a specific direction, our scheme has the lower location management cost than that of the distance-based scheme.

• Journal of KIISE:Databases
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• v.35 no.6
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• pp.459-468
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• 2008

A data stream which is a massive unbounded sequence of data elements continuously generated at a rapid rate. Many recent research activities for emerging applications often need to deal with the data stream. Such applications can be web click monitoring, sensor data processing, network traffic analysis. telephone records and multi-media data. For this. data processing over a data stream are not performed on the stored data but performed the newly updated data with pre-registered queries, and then return a result immediately or periodically. Recently, many studies are focused on dealing with a data stream more than a stored data set. Especially. there are many researches to optimize continuous queries in order to perform them efficiently. This paper proposes a query optimization algorithm to manage continuous query which has multiple join operators(Multi-way join) over data streams. It is called by an Extended Greedy query optimization based on a greedy algorithm. It defines a join cost by a required operation to compute a join and an operation to process a result and then stores all information for computing join cost and join cost in the statistics catalog. To overcome a weak point of greedy algorithm which has poor performance, the algorithm selects the set of operators with a small lay, instead of operator with the smallest cost. The set is influenced the accuracy and execution time of the algorithm and can be controlled adaptively by two user-defined values. Experiment results illustrate the performance of the EGA algorithm in various stream environments.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.659-668
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• 2006

Various schemes for mobility support are currently proposed in NGN. However the performance comparison of all existing schemes is not relatively examined as yet. Therefore, in this paper, we investigate the location registration and handover procedure of MIPv6, IP2, Q.MMF, IMS, compare and analyze the location registration time and cost and handover latency time using various performance parameters and simulation for the performance analysis. As a result of analysis, when Location Manager locates in the center of core network, IP2 showed better performance than other schemes.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.261-262
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• 2012

최근 인터넷의 발달로 활발히 게시되고 있는 전문 지식 정보들이 유용한지를 판별하기 위해 시맨틱 웹 등의 기술을 이용한 다양한 소프트웨어들이 개발되고 있다. 이러한 소프트웨어들은 개별적으로 우수하게 지식을 판단할 수 있는 수단을 제공하지만, 이를 통합적으로 관리하여 사용자들의 요구에 적합하게 유용한 소프트웨어를 개발할 수 있는 시스템은 현재 미미한 상태이다. 따라서 이러한 소프트웨어 및 데이터를 통합적으로 관리할 수 있는 시스템이 필요하다. 이를 위해 본 논문에서는 소프트웨어 및 데이터의 통합을 통해 사용자가 원하는 소프트웨어를 등록하고, 이를 데이터와 통합하여 사용할 수 있는 실행 환경을 제공하는 콘텐츠 관리 시스템을 설계한다. 제안하는 시스템은 기존 콘텐츠 관리 시스템보다 사용자가 동적으로 소프트웨어를 등록 및 사용할 수 있는 환경을 제공하기 때문에 경제적인 측면에서는 비용을 절감할 수 있는 콘텐츠를 선택할 수 있으며, 관리적인 측면에서는 소프트웨어 및 데이터 자원의 재활용성을 높일 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.406-416
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• 1995

This paper is concerned with a routing protocol for cost-effective communications between mobile hosts on computer networks in which mobile hosts can move freely their physical positions. The proposed routing protocol consists of two protocols : one is called location registration protocol performing registration of the location information as the mobile host does move; the other one is called message transfer protocol which actually delivers a message to the destination mobile host. The detailed protocol's operational behavior and major characteristics are presented. And it is shown that our protocols are superior to previous ones, in terms of the communication cost(i.e, number of messages) required for routing a message, and are functionally improved ones.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.1353-1356
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• 2021

블록체인은 다수의 노드 네트워크 내에서 거래내역을 분산 저장함으로써 투명성을 확보하는 기술이다. 최근에는 금전적 가치를 지닌 선하증권(Bill of Lading, B/L 서류)에 블록체인을 적용하여 무결성을 확보하고 거래 과정을 간소화 하기위한 연구가 진행되고 있다. 본 논문에서는 거래자 중심의 블록체인 기반의 선하증권 시스템을 제안한다. 수출자는 발행 받은 선하증권을 AI(Artificial intelligence)기반의 OCR(Optical character recognition)기능을 통해 블록체인에 등록하고, 각국 은행에서 열람하여 신용장거래를 진행한다. 수입자는 선하증권 정보를 담은 QR(Quick Response code)코드로 자기증명을 하여 물품을 인도 받게 된다. 이는 수출자 측에서는 선적서류를 우편으로 보낼 시간과 비용을 단축하고, 서류의 무결성을 입증할 수 있다는 점에서 큰 효과를 얻을 수 있다. 수입자 측에서는 서류가 등록됨과 동시에 확인할 수 있고, 해당 거래를 신뢰할 수 있다는 이점을 갖는다. 마지막으로 은행 측에서는 선적서류에 대해 보안성을 갖출 수 있고 검증이 더 신속하게 이루어질 수 있다.

• Journal of Internet of Things and Convergence
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• v.5 no.2
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• pp.67-72
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• 2019

As Internet voting can take place regardless of a voter's location, the participation rate of the voters would be increased and economic costs will be reduced. But the drawback of it is that all participants have to trust the election management server. If the server colludes with the specific candidate, the other candidates cannot prove rigged election. In addition, majority of researches on Internet voting are mainly focused on the voting restricted by the region and the country. Thus, it's not appropriate for the election in Internet community such as YouTube channels. As the Internet community is composed of members from all around the world, the new type of voting model is needed. In this study, we propose the smart contract based Internet voting model applicable on the blockchain network. The proposed smart contract model consists of candidate registration, voter registration, voting and counting stages. In the proposed model, anonymity of the voter is assured in the voter registration and voting stages, and all candidates can confirm the fairness of the election in the counting stage.

• Journal of Agricultural Extension & Community Development
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• v.19 no.1
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• pp.147-178
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• 2012

청정개발체제(CDM)는 1997년 교토의정서(Kyoto protocol)를 통해 확립된 온실가스 배출과 관련된 선진국과 개도국 간 협력 기제의 하나이다. 청정개발체제는 기본적으로 선진국의 정부 또는 민간조직이 개도국에서 배출감축 프로젝트를 수행하고, CER(Certified Emission Reduction)의 형태로 배출권을 얻는 것을 허용하고, CER을 자국의 배출감축목표 달성을 위해 사용할 수 있도록 하고 있다. 이 연구의 목적은 아세안 국가들의 청정개발 메커니즘의 성취도를 알아보는데 있으며, 자료는 2010년 10월 15일 현재 유엔기후변화기본협약(UNFCCC)에 등록된 254개 청정개발체제 사업을 대상으로 분석하였다. 이 연구의 결과, 전체 254개 사업 중 20%만이 탄소배출권을 받은 것으로 나타났으며, 실제 탄소배출권의 총량은 650만 톤이지만, 이는 전체 사업계획서에 반영된 양의 15%에 불과한 것으로 분석되었다. 또한 아세안 국가의 CDM사업과 관련된 장애 요인으로서는 (1) 사업 등록과 탄소배출권 승인 간 시간 격차가 존재하고, (2) 사업계획과 실제 승인량에 차이가 나타나며, (3) 특히 소규모 사업의 경우 높은 거래 비용 때문에 등록 후 배출승인을 신청하지 않고 있는 것으로 나타나고 있다. 이러한 연구결과는 아세안국가들이 CDM사업을 수행하는 데 있어서 선진국들의 주요 파트너가 되고 있지만, 실제로 사업을 통한 탄소배출량은 제한적일 수 있음을 의미한다. 따라서 일부 아세안 국가에서 교토의정서에 따라 자체적으로 탄소배출감축을 시도하고 있음을 고려할 때, 자체적인 CDM의 성공적인 경영, 수행, 운영을 위해 더 많은 선진국들의 협력과 지원이 주어질 필요가 있다.