• ETRI Journal
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• v.29 no.3
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• pp.381-389
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• 2007

In this paper we propose a graph-theoretic method based on linear congruence for constructing low-density parity check (LDPC) codes. In this method, we design a connection graph with three kinds of special paths to ensure that the Tanner graph of the parity check matrix mapped from the connection graph is without short cycles. The new construction method results in a class of (3, ${\rho}$)-regular quasi-cyclic LDPC codes with a girth of 12. Based on the structure of the parity check matrix, the lower bound on the minimum distance of the codes is found. The simulation studies of several proposed LDPC codes demonstrate powerful bit-error-rate performance with iterative decoding in additive white Gaussian noise channels.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.231-234
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• 2001

This paper proposes a face recognition technique that effectively combines elastic graph matching (EGM) and Fisherface algorithm. EGM as one of dynamic lint architecture uses not only face-shape but also the gray information of image, and Fisherface algorithm as a class specific method is robust about variations such as lighting direction and facial expression. In the proposed face recognition adopting the above two methods, the linear projection per node of an image graph reduces dimensionality of labeled graph vector and provides a feature space to be used effectively for the classification. In comparison with a conventional method, the proposed approach could obtain satisfactory results in the perspectives of recognition rates and speeds. Especially, we could get maximum recognition rate of 99.3% by leaving-one-out method for the experiments with the Yale Face Databases.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.66-75
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• 1998

In many case of optimal design and sensitivity analysis, obtaining of transfer function between input and output variables is a difficult and time-consuming problem. The bond graph modeling is a method that is used for making it easy to analyze complex systems composed of mechanical and electrical parts. It gives us a simple and systematic tool to get state-space equations easily. And we can obtain the transfer function graphically using bond graph and Mason's rule. This paper shows how bond graphs are converted to block diagram and how Mason's rule is applied. And the simple direct method to obtain transfer function from bond graph is introduced. As a example, induction of transfer function of electric power steering composed of mechanical and electrical parts will be done.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.25-31
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• 2016

There are many methods to describe the importance of a node, centrality, in a graph. In this paper, we focus on the eigenvector centrality. In this paper, an analytical method to estimate the difference of centrality with an additional edge in a graph is proposed. In order to validate the analytical method to estimate the centrality, two problems, to decide an additional edge that maximizes the difference of all centralities of all nodes in the graph and to decide an additional edge that maximizes the centrality of a specific node, are solved using three kinds of random graphs and the results of the estimated edge and observed edge are compared. Though the estimated centrality difference is slightly different from the observed real centrality in some cases, it is shown that the proposed method is effective to estimate the centrality difference with a short running time.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.1
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• pp.33-40
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• 1986

Unit-graph model to estimate the daily streamfiow was developed on the basis of distribution graph method. The results of evaluating the application of the model to Nakdong watersheds were generally satisfactory and this model would be the groundwork of the "Unit-graph model for daily streamflow in Korean watersheds".eds".uot;.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.265-271
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• 1997

A bond graph modeling approach which is equivalent to a finite element method is formulated in the case of the piezoelectric thickness vibrator. This formulation suggests a new definition of the generalized displacements for a continuous system as well as the piezoelectric thickness vibrator. The newly defined coordinates are illustrated to be easily interpreted physically and easily used in analysis of the system performance. Compared to the Mason equivalent circuit model, the bond graph model offers the primary advantage of physical realizability. Compared to circuit models based on standard discrete electrical elements, the main advantage of the bond graph model is a greater physical accuracy because of the use of multiport energic elements. While results are presented here for the thickness vibrator, the modeling method presented is general in scope and can be applied to arbitrary physical systems.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.959-962
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• 2002

This paper presents a method of constructing the universal multiple processing element unit(UMPEU) based on De Bruijn Graph. The proposed method is as following. Firstly we propose transformation operators in order to construct the De Bruijn graph using properties of graph. Secondly we construct the transformation table of De Bruijn graph using above transformation operators. Finally we construct the De Bruijn graph using transformation table. The proposed UMPEU is capable of constructing the De Bruijn geraph for any prime number and integer value of finite fields. Also the UMPEU is applied to fault-tolerant computing system, pipeline class, parallel processing network, switching function and its circuits.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.64-72
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• 2003

A new reliability assessment methodology is presented and the new method is compared with fault tree analysis. The system is modeled by directed graph at a new methodology, which is composed of nodes and arcs. The directed graph corresponds to the layout of chemical process and is easy to construct. Therefore, the directed graph analysis is applicable to the chemical process that has complex sequence. The example of fault tree analysis and directed graph analysis is given. The directed graph analysis has proved to be a valuable and useful method for the reliability assessment of chemical process.

• International Journal of Computer Science & Network Security
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• v.24 no.5
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• pp.33-39
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• 2024

In a previous study we proceeded to the remodularization architecture based on classes and packages using the Formal Concept Analysis (FCA)[13] [14] [30]. we then got two possible remodularized architectures and we explored the issue of redistributing classes of a package to other packages, we used an approach based on Oriented Graph to determine the packages that receive the redistributed classes and we evaluated the quality of a remodularized software architecture by metrics [31] [28] [29]. In this paper, we will address the issue of the efficiency of the Oriented Graph in the remodularization of software architectures compared to the Formal Concept Analysis FCA method. The formal method of FCA concept is not popularized among scientists as opposed to the use of the labeled directed graph. It is for this reason that our directed graph approach is more effective in its simplicity and popularity.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.975-983
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• 2010

In this paper, we introduce extended problems of Tower of Hanoi (ToH) and propose a novel visualization method to express a state space of ToH. As for the extended problems, we introduce multi-peg ToH, multi-stack ToH, and regular state ToH. The novel visualization method in this paper is a natural extension of Hanoi graph visualization. In the proposed method, we assign one Cartesian coordinate point per each disk to provide an unified visualization that the marks on a link and the changes of a state should correspond with a peg position of a disk. Compared with Hanoi graph, the generated graph by the proposed method is isomorphic if we remove links of forbidden move, which indicates that our method is a generalization of Hanoi graph and thus is more expressive. To help the understanding of the readers, we show the generated graphs by our method when the number of disks is 2 and 3.