• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.153-158
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• 1995

Finding shortest paths in networks is the fundamental problem in network theory and has numerous in Operations Research and related fields. The purpose of this study is to present a algorithm for solving the length of the shortest paths from a fixed node in a general network in which the arc distance can be arbitrary value. This algorithm has a worst computational bound of $n^3/4$ additions and $n^3/4$ comparisons, which is lower the worst computational bounds of other available algorithms.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1398-1401
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• 1993

The computer users who desire the comprehensive use of an advanced network system which permits to link the diversified types of computer from one to others, still tend to increase in number. However, one of the ways to install a highly reliable facilities relative to the network system is to inherit the know-how preserved in the specific technology. Therefore, we will propose the solution of this problem. This paper describes COMNETS, an expert system for constructing distributed networks.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1334-1337
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• 1993

In this study, we newly formulated the link capcity allocation problem and the link capacity allocation and routing problem in an voice/data integrated network by the fuzzy set concept. We developed efficient algorithms for the above fuzzified problems and successfully showed that the fuzzy set theory is the powerful tool for the design problems in communication networks.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.211-213
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• 1993

In this paper, we proposed a design method of self-learning fuzzy logic controller using fuzzy neural network. The parameters of membership function in premise are modified by descent method and also consequent parameters by learning mechanism of animal conditioning theory. The proposed method is applied to pole balancing system in order to confirm the feasibility.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.406-414
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• 2020

Exporting plays the important role in reducing dependence on the domestic market by creating the new foreign markets. As a business strategy, exporting contributes to the national growth and provides firms with opportunities which enable economies of scale, economies of scope, and experience curve effects. Because of both the growth limitation of the domestic market and development of information technology, many firms enter in foreign markets by increasing exporting. Using firms located in Taegu, this study examined the factors of firms' exporting with industrial organization theory and strategic perspective. In the empirical results on industrial organization theory, systematic cooperation and governmental supporting positively affect firms' exporting and only systematic cooperation positively affects exporting performance. In the empirical results on strategic perspective, product differentiation foreign exporting network, and foreign entry nation positively affect firms' exporting, and foreign exporting network, and foreign entry nation positively affect exporting performance.

• Journal of Korea Water Resources Association
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• v.31 no.4
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• pp.439-448
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• 1998

There are many methods to calculate steady-state flowrate in a large water distribution system. Linear method which analyzes continuity equations and energy equations simultaneously is most widely used. Though it is theoretically simple, when it is applied to a practical water distribution system, it produces a very sparse coefficient matrix and most of its diagonal elements are to be zero. This sparsity characteristic of coefficient matrix makes it difficult to analyze pipe flow using the linear method. In this study, a graph theory is introduced to water distribution system analysis in order to prevent from producing ill-conditioned coefficient matrix and the technique is developed to produce positive-definite matrix. To test applicability of developed method, this method is applied to 22 pipes and 142 pipes system located nearby Taegu city. The results obtained from these applications show that the method can calculate flowrate effectively without failure in converage. Thus it is expected that the method can analyze steady state flowrate and pressure in pipe network systems efficiently. Keywords : pipe flow analysis, graph theory, linear method.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.9
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• pp.49-57
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• 1999

The fusion of fuzzy set theory and neural networks technologies have concentrated on applying neural networks to obtain the optimal rule bases of fuzzy logic system. Unfortunately, this is very hard to achieve due to limited learning capabilities of neural networks. To overcome this difficulty, we propose a new approach in which rough set theory and neuro-fuzzy fusion are combined to obtain the optimal rule base from input/output data. Compared with conventional FNN, the proposed algorithm is considerably more realistic because it reduces overlapped data when construction a rule base. This results are applied to the construction of inference rules for controlling the temperature at specified points in a refrigerator.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.129-136
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• 2020

The purpose of this study is to identify the influence of external-social and cultural factors on the perception of corruption in the public society through the Structural Equation Model(SEM) and to seek ways to reduce corruption in the public society. Currently the level of corruption in public sectors that people think is still large, and it is necessary to continuously reduce corruption in public sectors in order to improve national competitiveness. Since one society is a part of a country in system theory and social network theory, public society needs quantitative research in order to find the causes of corruption and solve them. The model was built and the variables were defined in SEM based on 600 questionnaires. As a result of analysis, corruption in public offices has decreased since the implementation of the solicitation and graft law, and socio-cultural factors have had a direct impact on corruption in public offices. The further research area is to seek detailed ways for transforming the education and awareness of civil society across the country in addition to the efforts of the public officials themselves in order to reduce corruption in public offices.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.4
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• pp.1392-1403
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• 2015

The rapid development of both communication traffic and increasing optical network sizes has increased energy consumption. Traditional algorithms and strategies don't apply to controlling the expanded network. Immunization algorithms originated from the complex system theory are feasible for large-scale systems based on a scale-free network model. This paper proposes the immunization strategy for complex systems which includes random and targeted immunizations to solve energy consumption issues and uses traffic to judge the energy savings from the node immunization. The simulation results verify the effectiveness of the proposed strategy. Furthermore, this paper provides a possibility for saving energy with optical transmission networks.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.4
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• pp.22-27
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• 2000

In this paper, new neural network called dynamic multidimensional wavelet neural network (DMWNN) is proposed. The resulting network from wavelet theory provides a unique and efficient representation of the given function. Also the proposed DMWNN have ability to store information for later use. Therefore it can represent dynamic mapping and decreases the dimension of the inputs needed for network. This feature of DMWNN can compensate for the weakness of diagonal recurrent neural network(DRNN) and feedforward wavelet neural network(FWNN). The efficacy of this type of network is demonstrated through experimental results.