• Journal of the Korean Society of Safety
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• v.12 no.4
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• pp.180-190
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• 1997

A new method in the fault tree analysis (FTA) for the reliability calculation is suggested. Two steps are necessary in traditional method in evaluation of the occurrence probability of top event in fault tree (FT). The first step is to find the minimal outsets, and the second one is to substitute the result into the poincare equation. In order to reduce the enormous computing time of this method, lots of rapid algorithms have been developed. Almost of all achievements were, however, based on the partial structural properties of FT. In this paper, the FT is transformed to a non-linear graph G which has the same minimal outsets of original n, and then the reliability is calculated using the domination theory. In this new method, the required number of equation terms are at most $2^n$ (n is node number of graph G), while $2^m$-1 (m is the number of minimal cutsets) calculation terms are required in the poincare equation in traditional method. Since m>>n in general. our new method reduces the calculation time significantly.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.6
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• pp.437-450
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• 2009

In this paper, we propose seven edge labeling methods. The methods produce three case of edge labels-sets of Fibonacci numbers {$F_k|k\;{\geq}\;2$}, {$F_{2k}|k\;{\geq}\;1$} and {$F_{3k+2}|k\;{\geq}\;0$}. When a sort of interconnection network, the circulant graph is designed, these edge labels are used for its jump sequence. As a result, the degree is due to the edge labels.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.6
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• pp.263-272
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• 2008

We propose and analyze a new interconnection network, called petersen-torus(PT) network based on well-known petersen graph. PT network has a smaller diameter and a smaller network cost than honeycomb torus with same number of nodes. In this paper, we propose optimal routing algorithm and hamiltonian cycle algorithm. We derive diameter, network cost and bisection width.

• Journal of Information Science Theory and Practice
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• v.6 no.3
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• pp.6-15
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• 2018

With the increasing demand for intelligent services, knowledge graph technologies have attracted much attention. Various application-specific knowledge bases have been developed in industry and academia. In particular, open knowledge bases play an important role for constructing a new knowledge base by serving as a reference data source. However, identifying the same entities among heterogeneous knowledge sources is not trivial. This study focuses on extracting and determining exact and precise entities, which is essential for merging and fusing various knowledge sources. To achieve this, several algorithms for extracting the same entities are proposed and then their performance is evaluated using real-world knowledge sources.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.60-71
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• 1996

Mostof existing CAD systems do not provide the advanced function for systematic checking of design and drafting errors in mechanical drawings. We have reported a computer aided drawing check system to single plane projection drawings made by a CAD system. This paper describes a checking method of dimensioning errors in mechanical drawings. The checking items are deficiency and redundancy of dimensions, input-errors in dimension figures and symbols, etc. Checking for deficiency and redundancy of global dimensions has been performed applying Graph Theory. This system has been applied to several examples and we have confirmed the feasibility of this checking method.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.213-220
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• 2008

The object of this paper is to propose a method to deal with the problem of modeling user specifications in approaches based on supervisory control and Petri nets. However, most of Petri Net approaches are based on forbidden states specifications, and these specifications are suitable the use of tool such as the reachability graph. But these methods were not able to show the user specification easily and these formalisms are generally limited by the combinatorial explosion that occurs when attempting to model complex systems. Herein, we propose a new efficient method using FSSTP (Forbidden Sequences of State-Transitions Problem) and theory of region. Also, to detect and avoid the deadlock problem in control process, we use DAPN method (Deadlock Avoidance Petri nets) for solving this problem in control model.

• Korean Journal of Computational Design and Engineering
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• v.6 no.3
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• pp.174-183
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• 2001

This study proposes an improved genetic algorithm (GA) to derive solutions for facility layout problems having inner walls and passages. The proposed algorithm models the layout of facilities on a flour-segmented chromosome. Improved solutions are produced by employing genetic operations known as selection, crossover, inversion, mutation, and refinement of these genes for successive generations. All relationships between the facilities and passages are represented as an adjacency graph. The shortest path and distance between two facilities are calculated using Dijkstra's algorithm of graph theory. Comparative testing shows that the proposed algorithm performs better than other existing algorithm for the optimal facility layout design. Finally, the proposed algorithm is applied to ship compartment layout problems with the computational results compared to an actual ship compartment layout.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.4
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• pp.591-600
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• 1998

The scheduling of parallel computing systems consists of two procedures, the assignment of tasks to each available processor and the ordering of tasks in each processor. The assignment procedure is same with a clustering. The clustering is classified into linear or nonlinear according to the precedence relationship of the tasks in each cluster. The parallel computing system can be modeled with a Directed Acyclic Graph(DAG). By the granularity theory, DAG is categorized into Coarse Grain Type(CDAG) and Fine Grain Type(FDAG). We suggest the linear clustering method for the scheduling of CDAG using the genetic algorithm. The method utilizes a properly that the optimal schedule of a CDAG is one of linear clustering. We present the computational comparisons between the suggested method for CDAG and an existing method for the general DAG including CDAG and FDAG.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.2
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• pp.93-99
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• 2001

A new type geometric and mathematical network reduction model is introduced. Large-scale network is analyzed with analytic approach. The graph has many nodes, branches and loops. Circuit equation are obtained from these elements and connection rule. In this paper, the analytic relation between voltage source has a mutual different graphic property. Node-reduction procedure is achieved with this circuit property. Consequently voltage source value is included into the adjacent node-analyzing equation. A resultant model equations are reduced as much as voltage source number. Matrix rank is (n-1-k), where n, k is node and voltage source number. The reduction procedure is described and verified with geometric principle and circuit theory. Matrix type circuit equation can be composed with this technique. The last results shall be calculated by using computer.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.4
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• pp.392-401
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• 2000

In this work, a deadlock avoidance strategy is proposed in order to effectively handle conflicts and deadlocks occurring in zone-control AGV (Automated Guided Vehicle) systems. The basic idea is based on Capacity-designated Directed Graph (CDG) theory that was developed to avoid from deadlocks in manufacturing systems. However, to enforce the effectiveness of detecting impending and restricted deadlocks, AGV routings are explicitly described in Extended Directed Graph (EDG). From EDG, a non-conservative deadlock-avoidance strategy is derived. The superiority of the proposed strategy lies on the applicability to diverse AGV path configurations using zone control. Also, because of its insensibility and robustness, it can be effectively used when the system has randomness and stochastic nature.