• 한국가스학회지
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• 제2권1호
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• pp.53-58
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• 1998

화학공정 변수간의 관계를 표현하는 방법으로, 지식기반 접근법을 이용하여 부호유향그래프(signed directed graph, SDG)를 자동합성하였다. SDG의 자동합성은 지식베이스를 이용한 추론과정 및 Loop 검증의 두 단계를 거쳐 수행된다. 먼저, 공정내 장치를 중심으로 장치간의 결합관계를 Topology로 표현하고, Topology 정보를 이용한 공정 변수관계 표현 및 지식베이스의 공정경향 데이타를 문자 패턴 매칭하여 Primary-SDG를 자동으로 합성한다. 생성된 Primary-SDG를 Loop 검증기의 추론을 통하여 검증, 수정하여 SDG를 자동합성하였다.

• Korean Journal of Mathematics
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• 제21권1호
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• pp.55-62
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• 2013

The base $l(S)$ of a signed digraph S is the maximum number $k$ such that for any vertices $u$, $v$ of S, there is a pair of walks of length $k$ from $u$ to $v$ with different signs. A graph can be regarded as a digraph if we consider its edges as two-sided arcs. A signed cyclic graph $\tilde{C_n}$ is a signed digraph obtained from the cycle $C_n$ by giving signs to all arcs. In this paper, we compute the base of a signed cyclic graph $\tilde{C_n}$ when $\tilde{C_n}$ is neither symmetric nor antisymmetric. Combining with previous results, the base of all signed cyclic graphs are obtained.

• East Asian mathematical journal
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• 제28권5호
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• pp.579-585
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• 2012

Let D be a finite digraph with the vertex set V(D) and arc set A(D). A two-valued function $f:V(D){\rightarrow}\{-1,\;1\}$ defined on the vertices of a digraph D is called a signed 2-independence function if $f(N^-[v]){\leq}1$ for every $v$ in D. The weight of a signed 2-independence function is $f(V(D))=\sum\limits_{v{\in}V(D)}\;f(v)$. The maximum weight of a signed 2-independence function of D is the signed 2-independence number ${\alpha}_s{^2}(D)$ of D. Recently, Volkmann [3] began to investigate this parameter in digraphs and presented some upper bounds on ${\alpha}_{s}^{2}(D)$ for general digraph D. In this paper, we improve upper bounds on ${\alpha}_s{^2}(D)$ given by Volkmann [3].

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.860-863
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• 1997

FCM(Fuzzy Cognitive Map) is a fuzzy signed directed graph for representing causal reasoning which has fuzziness between causal concepts. Authors have already proposed FCM-based fault diagnostic scheme. However, the previously proposed scheme has the problem of lower diagnostic resolution. In order to improve the diagnostic resolution, a new diagnostic scheme based on extended FCM which incorporates the concept of fuzzy number into FCM is developed in this paper. Furthermore, an enhanced TAM(Temporal Associative Memory) recall procedure and pattern matching scheme are also proposed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.389-394
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• 1989

본 연구에서는 화학공정의 자동화와 관련된 실시간 나프타 분해로 이상진단 시스템의 한 부분을 구성하고 있는 지식기반의 구현을 위하여 공정변수 상호간의 관계를 나타낸 signed directed graph(SDG)를 기반으로 이상에서 파급되는 증상들을 순서대로 나타내는 fault-consequence digraph(FCD)를 지식모델로 사용했고, 이를 사고사례를 이용하여 검토해본 결과 초기에 정확한 이상원인 후보를 찾아내므로써 이상진단 전문가 시스템의 지식모델로 적합함을 알 수 있었다.

• 한국가스학회지
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• 제2권3호
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• pp.12-17
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• 1998

공정의 위험성 평가를 위한 이상트리 작성은 많은 시간과 인력을 요하는 작업으로 대규모 화학공장에 적용하기가 매우 힘들다. 본 연구에서는 화학공정의 이상트리 합성을 위해서, 공정변수간의 인과관계를 나타내는 부호 유향그래프로 발생 가능한 모든 공정이상과 원인들을 표현하고, 부호 유향그래프상에 존재하는 경로특성에 따라 일반 조작자와 루프 조작자를 정의하여 이상사건의 원인을 탐색할 때 해당하는 경로의 특성에 맞는 조작자로 대치함으로써 이상트리를 자동합성하였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1997년도 추계학술대회 학술발표 논문집
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• pp.247-251
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• 1997

FCM(Fuzzy Cognitive Map) is a fuzzy signed directed graph for representing causal reasoning which has fuzziness between causal concepts. Authors have already proposed FCM-based fault diagnostic scheme and verified its usefulness. However, the previously proposed scheme has the problem of lower diagnostic resolution as in the case of other qualitative approaches. In order to improve the diagnostic resolution, a concept of fuzzy number is introduced into the basic FCM-based fault diagnostic algorithm. By incorporation the fuzzy number into fault FCM models, quantitative information such as the transfer gain between the state variables can be effectively utilized for better diagnostic resolution. Furthermore, an enhanced TAM(Temporal Associative Memory) recall procedure and modified and modified pattern matching scheme are also proposed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.233-238
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• 1993

In this paper, two diagnosis algorithms using the simple fuzzy, cognitive map (FCM) that is an useful qualitative model are proposed. The first basic algorithm is considered as a simple transition of Shiozaki's signed directed graph approach to FCM framework. And the second one is an extended version of the basic algorithm. In the extension, three important concepts, modified temporal associative memory (TAM) recall, temporal pattern matching algorithm and hierarchical decomposition are adopted. As the resultant diagnosis scheme takes short computation time, it can be used for on-line fault diagnosis of large scale and complex processes that conventional diagnosis methods cannot be applied. The diagnosis system can be trained by the basic algorithm and generates FCM model for every experienced process fault. In on-line application, the self-generated fault model FCM generates predicted pattern sequences, which are compared with observed pattern sequences to declare the origin of fault. In practical case, observed pattern sequences depend on transport time. So if predicted pattern sequences are different from observed ones, the time weighted FCM with transport delay can be used to generate predicted ones. The fault diagnosis procedure can be completed during the actual propagation since pattern sequences of tvo different faults do not coincide in general.