• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.77-89
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• 2005

As the ID-based public key cryptosystems become a very active research area, a number of ID-based key agreement protocols have been proposed, but unfortunately many of them were analyzed that there were some security flaws in the protocols. In addition to key agreement protocols, in recent, Liu et al. and Kim et al. proposed the key agreement protocols that multiple session keys are established at once among participated entities. In this paper, we propose an ID-based tripartite key agreement protocol that establishes 8 keys by improving the efficiency of the Liu et al's. Moreover, the proposed protocol can be used in the situation where multiple different private key generators(PKG) are involved. Therefore, because the private key issued by different PKGs belonging to each entity's domain can be used, our proposed scheme is more efficiently applicable to the practical applications.

• Journal of Korea Multimedia Society
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• v.9 no.7
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• pp.773-781
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• 2006

XML is a standard language to express and exchange the data over the web. Recently, researches about techniques that storing XML documents into RDBMS and managing it have been progressed. These researches use a technique that are receiving the DTD document as an input and generate the relational schema from it. Existing researches, however, do not consider the semantic preservation because of the simplification of the DTD. Further, because existing studies only focus on the preservation technique to store information such as content and structure, there is a troublesomeness that have to use the stored-procedure or trigger for the data integrity during the stores of XML documents. This paper proposes a improved Inlining technique to create effective relations and to preserve semantics which can be inferred from DTD.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.69-78
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• 1999

Recently, with a rapid industry development, the recognition of environmental pollution is being increased. And the technique of pollution-prevention is also being studied. In the past, management direction for environmental pollution was limited only to concentration reduction and technique for treatment. But ,in these day, its direction is moved to a high level study such as a management and estimation of pollution material. In this study we establish a conception about EIS(Environmental Information System) building and present its building method. And we present a method for a database building, searching, analysis and printing. Also we produced the landuse map processing LANDSAT TM image. Using DDE(Dynamic Data Exchange) between Excel and ArcView on PC platform, we are enable to write and/or update a Report - waste discharge facility approval management leader - and to recover weakness about the report management of exsiting GSIS program.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1458-1464
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• 2005

A P2P is a method that can share and exchange on digital resources through a direct connection on personnel without a central server. In this paper, Although the P2P application that uses our proposed framework should obtain one or more IP addresses of the neighbor peers manually, after instantiate, the application can do its job while maintaining connection to the network continuously and automatically. To evaluate our proposed scheme, we measured and analyzed the time for a peer to reconnect to the network when the mediating peer fails and the network isolation occurs.

• Korean Journal of Cognitive Science
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• v.15 no.3
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• pp.35-44
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• 2004

As the use of internet becomes proliferated, a great amount of information is provided through diverse channels. Users require effective information providing service and we have studied the conversational agent that exchanges information between users and agents using natural language dialogue. In this paper, we develop a question answering agent providing the corresponding answer by analyzing the user's intention using artificial intelligence techniques such as pattern matching and Bayesian network We work out various problems in knowledge representation of users by constructing keyword synonym database. The proposed method is applied to designing an agent for the introduction of a fashion web site, which confirms that it responds more flexibly to the user's queries.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.153-165
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• 2007

XML is widely used in various applications as the standard for representing and exchanging data on the Web. XML Schema is the standard schema for XML and an XML document generated based on the XML Schema is called 'Valid XML document'. The XML Schema validity should be guaranteed after the XML document is updated. In this paper, we design an efficient method that verifies XML Schema validity before update, and so eliminates unnecessary validations. Also, we propose validation algorithms for each update. In addition, we propose the mapping between XML data and XML Schema and a storage method for XML Schema in order to efficiently extract the schema information for the validation. Finally, we compare the performance of the validation according to the storage methods.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.307-311
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• 2001

신속조형시스템(RP : Rapid Prototyping)용 자료교환 표준인 STL의 자료구조는 단순하고, 조형용 2차원 단면 자료로의 전환이 용이하며, 생산 가공 기술로서의 현대적인 특성(신속성, 조형성, 경제성, 청정성 등)을 가지고 이는 장점이 있는 반면에, STL 3D 좌표값의 기준(좌표계의 원점)이 되는 크기 정보가 없다. 이런 문제를 구현된 STL 뷰어에서는, 스케일링(scaling) 기법과 선형적인 이동 기법을 사용하여 해결하였고, CAD 시스템으로 제작된 파일 자체의 문제점 패싯(facet) 중복, 정밀도, 법선 벡터 값의 오류 등도 검증기(verifier)와 오류 정정기(error corrector)글 구현하여 해결하였다. 제안된 방법으로 구현된 STL 뷰어는 시스템의 안정성과 확장성, 그리고 효율성 측면에서 우수한 성능을 보였으며, 슬라이싱(slicing), 경로 추적기(path tracer)의 전처리기의 역할을 한다.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.35-43
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• 2011

Cognitive Radio (CR) ad hoc network is highly considered as one of promising future ad hoc networks, which enables opportunistic access to under-utilized licensed spectrum. Similarly to other CR networks, the spectrum sensing is a prerequisite in CR ad hoc network. Collaborative spectrum sensing can help increasing sensing performance. For such an infrastructureless network, however the coordination for the sensing collaboration is really complicated due to the lack of a central controller. In this paper, we propose a novel collaborative spectrum sensing scheme in which the final decision is made by the node with the highest data reliability based on a sequential Dempster Shafer theory. The collaboration of sensing data is also executed by the proposed contention-aware reporting mechanism which utilizes the sensing data reliability order for broadcasting spectrum sensing result. The proposed method reduces the collecting time and the overhead of the control channel due to the efficiency of the ordered sequential combination while keeping the same sensing performance in comparison with the conventional cooperative centralized spectrum sensing scheme.

• Journal of KIISE:Software and Applications
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• v.27 no.10
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• pp.1015-1027
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• 2000

에이전트에 대한 연구는 최근에 들어와 그 응용분야가 점차 확대되어 가고 있으며, 에이전트를 근간으로 하는 소프트웨어도 점점 복잡화, 대형화되고 있는 추세이다. 이에 따라 에이전트를 근간으로 하는 소프트웨어 개발 방식도 좀더 체계적이며 공학적인 접근이 요구되고 있다. 본 논문에서는 에이전트 기반의 소프트웨어를 효율적으로 모델링하기 위하여 에이전트 추출, 내부 에이전트 모델링과 외부 에이전트 모델링 기법을 제안한다. 에이전트 추출은 실세계에 존재하는 객체들로부터 에이전트를 추출하는 방법을 사용했고, 내부 에이전트 모델링에서는 에이전트의 내부를 목표, 자기정보, 계획 기능으로 나누어 각각의 모델링 방법을 제시했으며, 외부 에이전트 모델링에서는 다중 에이전트 시스템에서 에이전트의 이동성과 에이전트간의 메시지 교환을 중심으로 한 모델링 방법을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.434-436
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• 2012

최근에 모바일 시장의 급격한 성장과 함께, 모바일 애플리케이션의 보안약점을 통해 개인의 민감한 정보가 유출되는 심각한 문제점이 새롭게 등장하고 있다. 특히, 오늘날의 소프트웨어는 인터넷 환경에서 데이터를 교환하기 때문에 해커에 의해 악의적인 공격을 받을 가능성이 항상 존재한다. 이러한 보안약점은 심각한 경제적 손실을 발생시키는 소프트웨어 보안 침해사고의 직접적인 원인이다. 따라서 초기 개발 단계에서 보안약점을 제거하는 것이 중요하다. 그러나 기존의 보안약점 목록은 모바일 환경의 특성을 반영하지 못하고 있다. 본 논문에서는 모바일 애플리케이션의 특성을 고려한 보안약점의 분류 기법에 대한 소개를 한다.