• Proceedings of the CALSEC Conference
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• 2003.09a
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• pp.249-254
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• 2003

Object caching is a desirable feature to improve the both scalability and performance of distributed application systems for information infrastructure, the information management system leveraging the power of network computing. However, in order to exploit such benefits, we claim that the following problems: cache server placement, cache replacement, and cache synchronization, should be considered when designing any object cache system. We are under developing DOC: a Distributed Object Caching, as a part of building our information infrastructures. In this paper, we show how each problem is inter-related, and focus to highlight how we handle cache server deployment problem

• Journal of the Korean Society of Systems Engineering
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• v.1 no.2
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• pp.12-18
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• 2005

ACTDs exploit mature technologies to solve important military problems. A reducing budget, significant changes in threats, and an accelerated pace of technology development have challenged our ability to adequately respond to rapidly evolving military needs. This work describes ACTD management and its program applications. It is presented a prospective and applications of domestic defense acquisition programs.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.565-567
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• 2002

DDOS공격은 최근 인터넷 환경에서 큰 위험요소로 부각되고 있다. 하지만, DDOS공격을 완벽하게 막아내는 것은 현재까지 알려진 방법으로는 거의 불가능하다. 그 이유는DDOS 공격이 Vulnerability Exploit을 이용한 공격방법이 아니라 Network Resource를 고갈시켜서 공격대상 호스트의 서비스를 차단하기 때문이다. 그래서, DDOS공격을 방어하기 위해서는 DDOS공격 트래픽에 대한 정확한 분석과 탐지가 선행되어야 한다. 본 논문을 통해서 여러 가지 DDOS공격 Traffic의 특징을 살펴보고, Web traffic과의 차이를 통해 DDOS traffic을 탐지하는 방법을 제안하고자 한다.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.132-135
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• 2000

In this paper, we propose to exploit a multi-code CDMA scheme for power line communication (PLC) systems, and its performance on non-Gaussian impulse and harmonic noises is presented. The proposed multi-code CDMA scheme utilizes convolutional coding and block interleaving to combat with the non-Gaussian noises, and simulation results indicate effective alleviation of these noises, and thus significant bit error rate improvement by the proposed scheme even under strict restriction of frequency band allowed in PLC systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.211-214
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• 2002

Recently efficient image coding using zerotree have been proposed. In these methods, the locations of nonzero wavelet coefficient are enrolled with a tree structure, called zerotree, which ran exploit the self-similarity of the wavelet pyramid decomposition across different scales. These are very especially in low bit rate image coding. In this paper, two zerotree image rolling algorithm, EZW and SPHIT are briefly introduced, and a new zerotree searching scheme is proposed to emphasize the significance of a wavelet coefficient by its orientation as well as its scale.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.463-464
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• 2007

This paper presents the hardware-based genetic algorithm, written in VHDL. Due to parallel computation and no function call overhead, a hardware-based GA advantage a speedup over a software-based GA. The proposed architecture is constructed on a field-programmable gate arrays, which are easily reconfigured. Since a general-purpose GA requires that the fitness function be easily changed, the hardware implementation must exploit the reprogrammability.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06b
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• pp.34-36
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• 2006

In this paper we present a method of feature extraction for motor imagery single trial EEG classification, where we exploit nonnegative matrix factorization (NMF) to select discriminative features in the time-frequency representation of EEG. Experimental results with motor Imagery EEG data in BCI competition 2003. show that the method indeed finds meaningful EEG features automatically, while some existing methods should undergo cross-validation to find them.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.161-164
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• 2000

Recently efficient image coding using zerotree have been proposed. In these methods, the locations of nonzero wavelet coefficient are encoded with a tree structure, called zerotree, which can exploit the self-similarity of the wavelet pyramid decomposition across different scales. These are very especially in low bit rate image coding. In this paper, two zerotree image coding algorithm, EZW and SPHIT are briefly introduced, and a new zerotree searching scheme is proposed to emphasize the significance of a wavelet coefficient by its orientation as well as its scale.

• Review of KIISC
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• v.11 no.5
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• pp.63-77
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• 2001

최근 인테넷을 이용한 각종 해킹 및 사이버 범죄가 크게 증가하고 있으나, 아직까지 공격의 주범인 해커들의 수준을 파악하지 못한 상황이다. 과거에 해커 분류를 시도한 경우가 있었지만 적용한 분류 기준은 대부분 해커들의 행동 양식이었다. 이에 본 문서에서는 해킹 수행 코드(exploit code)를 작성할 수 있는 가의 여부를 바탕으로 해커의 능력을 분류하고 그들이 사용할 수 있는 해킹 기법과 그 수준을 확인해 보도록 한다. 이러한 해커의 수준에 따른 해킹 기법 분류를 기반으로 내부망의 보안성 평가에 활용할 수 있을 것이다.

• Journal of Korea Multimedia Society
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• v.7 no.6
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• pp.832-840
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• 2004

In ubiquitous environments, context is any information that can be used to characterize the situation of an entity such as a person or an object. Many sensors and small computers collect contexts and provide applications with them. Thus, ubiquitous applications need to represent contexts and exploit them effectively. In this paper, we design and implement a context-aware messaging system, called UMS (Ubiquitous Messaging System), based on Java and Jini. UMS can represent various contexts using XML scripts, and communicate text messages regardless of user's location using the proxy mechanism of Jini.