• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.117-125
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• 2003

The proposed mechanism has an group management server, which manages the information about both the receivers and the senders. Any receiver can dynamically join/leave the multicast VC. The signaling overload due to group membership changes is not concentrated on the sender, but it is distributed to many receivers for the scalability improvement. The associated signaling messages propagates from the receivers to the ATM switch dedicated to the multicast VC, and hence no signaling overload exists in the shared links there is no latency for the receiver to wait. Our proposed scheme is superior in the view of scalability, the efficiency and the latency to other schemes.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.2205-2208
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• 2003

대부분의 인터넷 서비스는 일대일 전송방식의 best-effort를 지향하는 유니캐스트(Unicast)가 보편화 되어있다. 하지만, 다자간 통신 서비스는 고려하지 않아 망 자원 이용측면에서 매우 비효율적이다. 최근, 인터넷방송이나 소프트웨어 분배, 원격 화상회의, 다중사용자 게임, 증권시세 정보서비스 등 다자간 멀티미디어 서비스가 주요 인터넷 사업으로 각광을 밭으면서, 멀티캐스트(Multicast) 전송기술의 사용범위가 점차 증가되고 있다. 멀티캐스트는 그룹참가자의 가입과 탈퇴가 빈번한 특징이 있어 키 전달 과정에서 네트워크의 과부하를 초래한다. 본 논문에서는 빈번하게 생성되는 그룹 키의 길이를 축소시켜 메시지의 생성과정을 단축하고, 독립된 그룹간 통신에 사용되는 유니캐스트에 IPSec(Internet Protocol Security Protocol)을 적용시켜 보다 안전하게 구간의 접근제어와 무결성 및 기밀성을 보장하는 SDKD(Secure Dynamic Key Distribution)를 제안한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.4
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• pp.77-89
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• 2001

Recently, with the explosive growth of communication technologies, group oriented services such as teleconference and multi-player game are increasing. Access control to information is handled by secret communications with group keys shared among members, and efficient updating of group keys is vital to such secret communications of large and dynamic groups. In this paper, we employ (2,4)-tree as a key tree, which is one of height balanced trees, to reduce the number of key updates caused by join or leave of members. Especially, we use CBT(Core Based Tree) to gather network configurations of group members and reflect this information to key tree structure to update group keys efficiently when splitting or merging of subgroups occurs by network failure or recovery.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1128-1131
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• 2009

폐쇄적 무선망 및 단말 플랫폼의 개방화 추세에 따라 이동통신사업자(MNO)는 자사 고객 retention 및 신규 수익창출을 위해 다양한 전략을 수립하고 있다. 그리고 고객은 이러한 개방 환경에서 이동통신사업자(MNO)의 단말 및 망에 구애받지 않고 자신의 개인정보 및 멀티미디어 컨텐츠 서비스를 편리하게 이용하기를 원하고 있다. 본 논문에서는 와이브로(WiBro)가입자 인증을 위해 단말에 필수 탑재되는 UICC 에 웹 기능 및 대용량 메모리 기술을 추가하여 이를 기반으로 개인화 서비스 제공을 위한 인프라 구축 사례를 살펴본다. 먼저, UICC 기반 개인화 서비스 인프라를 구성하는 UICC 및 단말에서 구현되어야 할 SCWS 및 대용량 메모리 처리 기술을 소개하고 이를 위한 기술 요구사항을 정의한다. 그리고, 해당 UICC 및 단말을 원격에서 관리하기 위해 플랫폼에서 구현하여야 할 제어 프로토콜 기술을 살펴보고, 이를 위한 기술 요구사항을 정의한다. 다음으로 최종적으로 구축된 전체 시스템의 구성 및 서비스 흐름을 기술하고, 끝으로 이러한 인프라를 통하여 제공될 수 있는 개인화 서비스를 소개하고 향후 방향을 소개함으로써 글을 맺는다.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.96-101
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• 2011

In recent days, the demand for the remote ECG monitoring system has been increasing and the automation of the monitoring system is becoming quite of a concern. Automatic detection of the abnormal ECG beats must be a necessity for the successful commercialization of these real time remote ECG monitoring system. From these viewpoints, in this paper, we proposed an automatic detection algorithm for the abnormal ECG beats using QRS width and RR interval patterns. In the previous research, many efforts have been done to classify the ECG beats into detailed categories. But, these approaches have disadvantages such that they produce lots of misclassification errors and variabilities in the classification performance. Also, they require large amount of training data for the accurate classification and heavy computation during the classification process. But, we think that the detection of abnormality from the ECG beats is more important that the detailed classification for the automatic ECG monitoring system. In this paper, we tried to detect the VEB which is most frequently occurring among the abnormal ECG beats and we could achieve satisfactory detection performance when applied the proposed algorithm to the MIT/BIH database.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.827-832
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• 2002

The development of dedicated network management system is essential to meet the following conditions: the system must run the configuring and repair processing for the dedicated communication network, and can manage new next generation data dedicated communication network of various types. In general it is effective that the system is consisted of decentralized module to be accessible for business logic and datum to remote area. To solve these problems, a method is to use object-oriented design techniques. That is, it is to abstract reusability objects and make component module using the abstracted objects. In this paper, we propose a management system of dedicated communication network service using object-oriented design techniques which are UML(Unified Modeling Language).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.6
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• pp.47-58
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• 2002

The access control techniques, which can control unauthorized members to access to multicast service, have not been studied very often while there are a lot of on-going study on secure multicast architecture, multicast key distribution and sender authentication scheme have been studied. Multi level access control scheme in multicast can be used in a remote secure conference or to provide graduated multimedia services to each customers. In fact, multicast network has its own virtual networks according to different security levels. However, Early schemes are not effective when it protects unauthorized access in multi-access network environment. Furthermore this scheme does not provide us with hierarchical access control mechanism. This paper, therefore, proposes hierarchical access control scheme to provide the effectiveness in network layer by security level comparison. And we also suggests hierarchical key distribution scheme for multi level access control in application layer and effective hierarchical key renewal scheme in dynamic multicast environment which is easy to join and leaving the multicast group.