• Journal of Digital Convergence
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• v.13 no.5
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• pp.245-250
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• 2015

The P2P technology is becoming a technology for receiving a service, such as the latest YouTube and Facebook. P2P technology can be easily downloaded to a large amount of multimedia content over a distributed environment. However, pictures, music, a large amount of multimedia content such as videos each user is unable to manage the content management operating smoothly because, Song communication processing overhead caused when the reception is likely to remain the problem. In this paper, we propose a convergence content management technique that provides a low communication overhead of the frequency of use of the convergence content when trying to provide a large amount of convergence content to users in a distributed environment. Our method can be used to select the appropriate frequency is high among the shared content on the P2P multimedia environments that are distributed across a frequency of use of the convergence content and provides the service. Experimental evaluation proposed method, the convergence content browsing speed than conventional techniques improved communication about 13.3% and reduced overhead to about 9.5%.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.55-62
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• 2010

While the broadband network and multimedia technologies have been developing, the commercial market of digital contents also has been widely spreading with recently starting IPTV. As the IPTV services are getting to be generalized and popularized, the contents illicit copying and distribution of copyright meterials tends to draw more attentions. So we need a right service system that can protect contents and copyright using watermark inserting. Until now, the conventional protection and authentication system is taking advantages of merits both in CAS and DRM. But this system can not protect the contents when acquiring them from TV output using A/D convertor. So we apply watermark method using HSI color space against contents illicit copying. And for distribution of copyright materials. we compound unique settop ID and copyrighter's ID to make new ID that is watermark. When inserting watermark, we use the watermark for copyright protection and authentication. So we can protect copyright and identify last settop's user in illicit distribution. we design download based IPTV contents protection and authentication system using HSI watermark method.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.813-817
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• 2008

Intelligent Robots (IR) get data of the current situation from sensors and perform knowledgeable services. Self-reconfiguration of IR is an important factor to change itself without stopping while supporting environment and technology change. In this paper, we propose an agent based self-reconfiguration framework of IR using ESB (Enterprise Service Bus). This framework focuses on dynamic discovery and reconfiguration of service-oriented applications using multi-agent system in intelligent robots. When IR meets an irresolvable situation it downloads a necessary service agent from an external service repository, executes the agent, and resolves the situation. Agent technology provides an intelligent approach for collaborations of IR. The prototype has also been implemented to show the validity of our study.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.70-70
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• 2011

기후변화 연구는 불확실한 미래를 전망하는 과정이므로 '불확실성'은 모든 기후변화 영향평가의 키워드임에 분명하다. 하지만 불확실성 평가를 위해 IPCC에서 제공되고 있는 수많은 GCM 시나리오를 모두 활용하기에는 많은 시간과 노력이 필요하기 때문에 이를 효율적으로 수행할 수 있는 방법이 필요하다 본 연구에서는 시나리오 저감(scenario reduction)방법을 이용하여, 수많은 GCM 시나리오 대신 몇 개의 대표적 GCM 시나리오로도 충분히 불확실성을 유지할 수 있는 시나리오 저감(scenario reduction)방법을 수립하고 제시하였다. IPCC 기후시나리오 중 20C3M과 A & B 배출시나리오를 바탕으로 생산되는 71개의 GCM 시나리오를 다운로드 받아 월평균 기온과 강수량에 대하여 한반도를 대상으로 분석하였다. 비교결과, 기온 전망은 실측과 비슷한 경향성을 보였으나 강수량은 홍수기를 모의하지 못하는 것으로 나타났다. 시나리오 저감방법은 시나리오 분류(scenario cluster)방법과 시나리오 선정(scenario selection) 방법으로 구성된다. 시나리오 분류방법에서는 k-mean방법을 이용하여 5개의 cluster로 나누었으며, 시나리오 선정방법에서는 GCM 시나리오 선정기법을 조사 분석하여 연구방향과 목적에 따라 GCM 시나리오 선정기법을 선택할 수 있는 표를 제시하고, 이 중 시나리오의 확률밀도함수를 이용하는 PDF method를 적용하였다. 본 연구에서는 불확실성 정량화를 위해 maximum entropy를 이용하였다. 또한 시나리오 저감방법이 불확실성을 유지하는지 비교하기 위해 PDF method를 이용하여 정확성이 높은 순으로 5개의 GCM 시나리오를 선정(best 시나리오)하여 불확실성을 정량화하였다. GCM 시나리오의 분산을 이용하여 maximum entropy를 산정한 결과, 20C3M 배출시나리오에서는 모든 시나리오의 entropy는 3.08, 시나리오 저감방법은 2.75, best 시나리오는 2.28이었으며, 이는 시나리오 저감방법은 모든 시나리오의 89.3%의 불확실성을 설명하고 있으나 best 시나리오는 74.0%밖에 설명하지 못한다는 것을 나타낸다. A & B 배출시나리오에서도 시나리오 저감 방법을 사용한 GCM 시나리오가 best 시나리오보다 모든 시나리오의 불확실성을 더 잘 설명하는 것으로 나타났다. 이와 같이 수많은 GCM 시나리오를 사용하는 것보다 몇 개의 대표 시나리오를 이용하여 기후 변화 불확실성을 유지하면서 미래전망을 할 수 있다면, 매우 효율적으로 기후변화 연구를 수행할 수 있을 것으로 사료된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1684-1691
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• 2016

Erasure codes have recently been applied to distributed storage systems due to their high storage efficiency. Regenerating codes are a kind of erasure codes, which are optimal in terms of minimum repair bandwidth. An (n,k,d)-regenerating code consists of n storage nodes where a failed node can be recovered with the help of the exactly d numbers of surviving nodes. However, if node failures occur frequently or network connection is unstable, the number of helper nodes that a failed node can contact may be smaller than d. In such cases, regenerating codes cannot repair the failed nodes efficiently since the node repair process of the codes does not work when the number of helper nodes is less than d. In this paper, we propose an operating method of regenerating codes where a failed node can be repaired from ${\bar{d}}$ helper nodes where $$k{\leq_-}{\bar{d}}{\leq_-}d$$.

• Journal of Information Management
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• v.39 no.4
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• pp.155-171
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• 2008

We constructed the integrated management system of distributed astronomical data of Bohyunsan Optical Astronomy Observatory(BOAO), Sobaeksan Optical Astronomy Observatory (SOAO), and Mt. Lemmon Optical Astronomy Observatory(LOAO). The observed data was stored in the archive of the observatory and MySQL table is saved in the integrated management system. There are data archive managers in the observatories and they manage the integrated management system such as data storing, head information extraction, table generation, and management of web pages, etc. The users can search and download all the data in the integrated management system web page. The concept of this system - send queries from web page to the observatory archives - is the same of the basic concept of virtual observatory. This research is one of the main work in the Korean virtual observatory which is take part in the international virtual observatory alliance.

• Journal of Internet Computing and Services
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• v.12 no.2
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• pp.55-62
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• 2011

To make service location protocol of IETF which is to be used in the wide area network to discover the location of desired service when computing resources are connected to the network, and to support simless connectivity between wired and wireless network in service viewpoint, to support the diversity trend of service agents in WIF, it needs to improve SLP, so as to add Liaison Agent and Forwarding Agent with FAAdvert message that is to communicate in between those entities. LA entity confirms the location of service located in wide area network, and FA transfers service information. The usage of existing messages such as SrvRqst, SrvRply, AttrRqst, AttrRply, DAAdvert, SrvReg, SrvAck, SrvDeReg is same as ever in wide area service network. The behaviors of improved protocol is modeled into petri-net and prove that it is free of deadlock and live-lock by execution of the model.

• Journal of Convergence for Information Technology
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• v.9 no.11
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• pp.15-21
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• 2019

Allowing only authorized users to record and inquire in the ledger, private blockchain technology is attracting attention from institutions and companies. Based on distributed ledger technology, records are immutable. Because news via the Internet can be easily modified, the possibility of manipulation is high. Some false communication report systems are designed to prevent such harm. However, during the gap between the false communication report and verification time, contents on the website can be modified, or false evidence can be submitted intentionally. We propose a system that collects evidence using a headless browser for more accurate false communication management, and securely preserves evidence through a private blockchain and prevents possibilities of manipulation. The proposed system downloads original HTML, captures the website as an image, stores it in a transaction along with the report, and stores it in a private blockchain to ensure the integrity from acquisition to preservation of evidence.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.129-137
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• 2009

While the broadband network and multimedia technologies have been developing, the commercial market of digital contents also has been widely spreading with recently starting IPTV. As the IPTV services are getting to be generalized and popularized, the contents protection and authentication system tends to draw more attentions. So we need a system that can protect contents and allow only authenticated person to use right service by controling user authority and using content encryption. Until now, the conventional protection and authentication system is taking advantages of merits both in CAS and DRM. But the weak point of this system are in high costs, complexity and using HW. For resolving these problems, in this paper, we proposed IPTV contents protection and authentication system using OTP. When we transmit the content encrypted by OTP key using contents delivery technology, we operate XOR with contents using another settop-box's OTP key which was transmitted from distribution server. And contents are reconstructed and transmitted to the settop-box, In the end, downloaded content are encrypted by OTP key and are superior in content protection when contents redistribution. Since OTP use double-authentication elements in encryption process, this method is excellent in content protection. And it is very effective in cost aspect because it could be implemented by SW program. Another benefit is that we can shorten the development time period. In this paper, we propose and find its possibility as a new content protection and authentication method suitable for IPTV services.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.57-66
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• 2010

CAS Client personalization means to issue CAS ID or Key for CAS service, which is Core Technology for CAS operation. Protocol A.1 on TTA.KR-07.0079 XCAS, stores CAS Client personalization data from CAS server in XCAS server, and transmits the personalization data by request of XCAS HOST for CAS Client personalization. However, this may increase Network Traffic and CAS Client image management in XCAS server. In this thesis, to complement this, CAS Client personalization is executed on CAS Server by separating CAS service field. Therefore this can distribute Image management and Network Traffic of XCAS server.