• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.205-205
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• 2006

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.478-480
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• 1989

이 논문(論文)에서는 페트리 넷트의 한 서브클래스인 활성(活性)이고 안전(安全)인 자유선택넷트의 가도달성(可到達成)에 관해 고찰했다. 활성(活性)이고 안전(安全)인 자유선택넷트의 한클래스가 가도달성(可到達成)을 가지기 위한 필요충분조건을 도출했다.

• Journal of Communications and Networks
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• v.12 no.2
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• pp.191-197
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• 2010

In this paper, we propose a novel methodology to identify border gateway protocol (BGP) updates associated with major events - affecting network reachability to multiple ASes - and separate them (statistically) from those attributable to minor events, which individually generate few updates, but collectively form the persistent background noise observed at BGP vantage points. Our methodology is based on principal component analysis, which enables us to transform and reduce the BGP updates into different AS clusters that are likely affected by distinct major events. We demonstrate the accuracy and effectiveness of our methodology through simulations and real BGP data.

• Electronics and Telecommunications Trends
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• v.13 no.6 s.54
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• pp.94-107
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• 1998

연구 개발의 주된 내용은 SDL(Specification Description Language)을 위한 정형기법 지원도구 중 명세상에서 행위 부분에 대한 동적 특성을 검정하는 검정기 개발이다. 모델 검정기는 해당 프로토콜에 대해 생성된 중간 모델 I/O FSM(Input/Output Finite State Machine)에 Modal-calculus에 의해 검정대상인 deadlock, livelock, reachability 및 liveness에 대한 표현과 I/O FSM에 대해 해당 알고리즘 적용 및 분석 기능을 C++언어로 구현하였다. 또한 SDL Editer 기능과 관련된 도구들과 통합하여 사용자들이 쉽고 편하게 쓸 수 있도록 환경 및 통합 모듈을 구현한다.

• ETRI Journal
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• v.11 no.4
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• pp.22-36
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• 1989

In this paper, a design and implementation of an efficient protocol verification system named LOVE has been described. The LOVE has been developed specifically for LOTOS. It performs not only protocol syntax validation (PSV) but also protocol functional verification(PFV). The PSV is a test to check if a protocol is free from protocol syntax errors such as deadlocks and livelocks. The PFV confirms whether or not a protocol achieves its functional objectives. For the PSV, the reachability analysis is employed, and the observational equivalence test is used for the PFV. For protocol verification using the LOVE, a schematic protocol verification methodology has been outlined.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.155-160
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• 1990

This paper presents the new VSMFC (variable structure model following control) algorithm of a system with parameter uncertainty. In contrast to the conventional approach, continuous control inputs am used instead of discontinous ones and modified reachability condition for sliding mode reduces a reaching phase and a newly proposed sliding surfaces are used for the robust control of uncertain system.

• Journal of Astronomy and Space Sciences
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• v.13 no.2
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• pp.134-148
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• 1996

In this paper, in order to verify KITSAT 1/2 packet communication protocols, we model the AX.25 protocol and PACSAT protocol by using an extended Petri net and then verify the correctness, boundedness, liveness and deadlock freeness of packet protocols by utilizing reachability trees.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.11a
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• pp.219-225
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• 2000

본 연구에서는 이산사건 동적 시스템을 모델링하고 성능을 분석하기 위한 통합 소프트웨어를 개발하였다. 소프트웨어는 페트리네트를 기반으로 비쥬얼 C++와 비쥬얼 베이직을 이용하여 개발되었으며 윈도우즈 환경 하에서 동작하는 범용 그래픽도구를 내장하고 있다. 본 소프트웨어를 이용하면 사용자는 마우스의 드래그 앤 드롭만으로 페트리네트 모델을 작성할 수가 있으며 모델이 작성되면 수리적 분석과 시뮬레이션을 통하여 시스템의 성능분석을 자동으로 수행하여 준다. 또한 시스템의 논리적인 특성을 분석하기 위하여 coverbility tree와 reachability tree를 지원한다. 이외에도 deadlock을 탐지하고 이를 해소하는 기능과 정교한 세부 모델링이 가능하도록 다양한 활성화 함수와 분포를 지원하며 시스템의 성능척도와 관련된 다양한 통계치를 제공해준다.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.641-644
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• 2000

This paper studies coverability tree and reach-ability set of Petri net under the earliest filing rule. Conventional algorithm for coverability tree for ‘normal’ Petri net is not good for Petri net under the earliest firing rule. More over, it is shown that there exists no coverability graph for general class of earliest firing Petri net. Some subclasses are studied where coverability graph can be constructed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.6
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• pp.408-414
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• 2004

In this paper, a disturbance observer based sliding mode control is proposed to attenuate disturbance responses in an active magnetic bearing system, which is subject to base motion. An algorithm which decouples disturbance observation dynamics from sliding mode dynamics is suggested. This algorithm preserves the robustness of the sliding mode control and satisfies reachability condition in the presence of external disturbance and parameter uncertainties. Along with experimental results, it is shown that the proposed control is effective in disturbance rejection without any additive disturbance measurement.