• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.10
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• pp.743-750
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• 2003

The equivalent source method(ESM) is used for the calculation of the internal pressure field for an enclosure which can have arbitrary boundary conditions and nay include internal objects which scatter the sound field. The advantage of using ESM is that it requires relatively low computing cost and is easy to model the internal diffracting objects. Typical ESM modeling uses two groups of equivalent source positions. One group includes the first order images of the source inside the enclosure. The Positions of the other group are usually on a spherical surface some distance outside the enclosure. The normal velocity on the surfaces of the enclosure walls is evaluated at a larger number of positions than there are equivalent sources. The sum of the squared difference between this velocity and the expected is minimized by adjusting the strength of the equivalent sources. This study is on the optimal far field sources positions when using the equivalent source method. In general, the far field sources are evenly distributed on a surface of a virtual sphere which is centered at the enclosure with a sufficiently large radius. In this study. optimal far field source locations are searched using simulated annealing method for various radii of spheres where far field sources are located. Simulation results showed that optimally located sources with adequate distance away from the enclosure center gave better result than sources with even distribution even with a smaller number of far field sources.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.216-221
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• 2001

The equivalent source method(ESM) is used for the calculation of the internal pressure field for an enclosure which can have arbitrary boundary conditions and may include internal objects which scatter the sound field. The advantage of using ESM is that it requires relatively low computing cost and is easy to model the internal diffracting objects. In the ESM modelling, some of the equivalent positions are chosen to be the same as the first order images of the source inside the enclosure, some are positioned on a spherical surface some distance outside the enclosure. The normal velocity on the surfaces of the enclosure walls is evaluated at a larger number of positions than there are equivalent sources. The sum of the squared difference between this velocity and the expected is minimized by adjusting the strength of the equivalent sources. This study is on the optimal equivalent source positions, the far field sources. Typically, the far field sources are evenly distributed on a surface of a virtual sphere which is centered at the enclosure with a sufficiently large radius. In this study, optimal far field source locations are searched using simulated annealing method and simulation results showed that optimally located sources gave better accuracy even with a smaller number of far field sources.

• Electrical & Electronic Materials
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• v.30 no.1
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• pp.22-29
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• 2017

• 정보화사회
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• s.188
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• pp.26-35
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• 2007

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.3
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• pp.23-39
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• 2004

This paper focused on empirically testing the ESM(Electronic-Store Success Model). The model was developed by basing upon the ‘Updated D&M(DeLone and McLean) IS Success Model(2003)’ and reflecting the characteristics of marketing and e-business, and composed of the six dimensions including system quality, information quality, service quality, trust, customer loyalty and financial performance. The research model consisting of five dimensions, excluding financial performance, was proposed and empirically verified by structural equation model with respect to data from 224 customers on 69 Electronic-Stores. The results show that system quality and information quality significantly influence service quality, and that service quality also significantly influence trust and customer loyalty, and that trust has significant influence on customer loyalty.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.710-711
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• 2015

최근 사이버 공격이사회, 국가적 위협으로 대두되고 있다. 최근 신종 악성코드에 의한 A.P.T 공격이 사회적으로 큰 혼란을 야기하고 있다. 이에 따라 기업 내에서 방화벽, IPS, VPN 등의 네트워크 보안 시스템의 통합 관리를 목적으로 하는 통합관제시스템(ESM)의 필요성이 제기되었다. 그러나 기존의 ESM의 방식은 외부에서 내부로 유입되는 트래픽만을 모니터링하는 네트워크 기반 공격 탐지기법을 사용하기 때문에, 외부 사이버 공격만을 차단할 수 있다는 한계점을 가지고 있다. 따라서 본 연구는 주요 IT 기반시설의 네트워크, 시스템, 응용 서비스 등으로부터 발생하는 데이터 및 보안 이벤트 간의 연관성을 분석하여 보안 지능을 향상시키는 빅데이터를 활용한 보안로그시스템을 제안한다. 본 연구에서 제안한 빅데이터를 활용한 보안로그시스템을 통해 분산 기반의 저장/처리 기술 적용하고자 한다.본 기술을 적용한 지능형 정보 분석 플랫폼 구성을 통해, 가용성과 확장성을 확보하여 통합적 보안 관제가 가능하도록 한다. 뿐만 아니라 기업 내로의 악성코드 유입, 감염(전파) 그리고 실시간 모니터링이 가능하여 고객 서비스 만족도가 향상되는 파급효과가 기대된다.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1521-1527
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• 2009

This study is aimed to analyze the floe patterns and thermal characteristics by computer simulation under the variations of fire strength for the logitudinal tunnel, from which flow and heat distributions are predicted in the longitudinal tunnel. Through the results of numerical computations, followings are found; one is that the volume flow rate is discontinuously increasing as closer to fire location, and the other is that a critical design to get the faster flow rate is required because of existence of backlayer flow for the high fire strength in view of safety for the people in fire of the tunnel.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.291-294
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• 2003

최근 보안 관련 사고의 급증으로 침입차단 시스템, 침입탐지 시스템 및 가상 사설망 등의 기능이 통합된 보안 관리시스템(ESM)에 대한 요구가 급증하고 있다. 효율적인 ESM 개발을 위해서는 개발자와 관련 단체들에 의한 표준화 작업이 필수적이며, 최근 ISTF는 침입차단 시스템(Firewall), 침입탐지 시스템(IDS) 및 가상 사설망(VPN)의 로그 형식 표준을 발표하였다. 그러나, ISTF의 표준은 통합보안관리시스템에서 필요한 이벤트 및 제어 등의 모든 사항들을 포함하고 있지 않아 이에 대한 추가 및 확장이 요구된다. 본 연구에서는 ISTF의 Firewall, IDS 및 VPN의 로그 형식을 분석하고 이 표준의 확장 개발을 위하여 추가되어야 할 항목에 대하여 논하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.74-79
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• 2002

In this paper, we designed the Policy-based ESM(Enterprise Security Management) for network security in Internet. First, we consider the existed network management and present ESM. And then analyze existent systems and drew consideration items at system design. This paper applied to PBNM technology in order to improve security network management.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.4
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• pp.322-322
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• 2019