• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1081-1090
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• 2015

This work proposes a theoretic framework for the performance assessment of an access point in the IP network that accommodates MD (Machine Data) and HD (Human Data). First, we investigate typical resource allocation methods in LTE for MD and HD. After that we carry out a Max-Min analysis about the surplus and deficiency of network resource seen from MD and HD. Finally, we evaluate the performance via numerical experiment.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.124-126
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• 2001

시차를 두고 발생한 사건속에서 잠재해있는 패턴을 발견하는 연속패턴(sequential pattern) 생성기술은 데이터 마이닝 분야에서 최근 관심을 모으고 있는 분야이다. 본 연구는 정보이론을 이용하여 데이터베이스로부터 연속패턴을 자동으로 발견하는 방법에 관한 내용이다. 본 연구에서 제시하는 방법은 기존의 방법과는 달리 테이블내의 모든 속성간의 연속패턴 관계를 탐지할 수 있으며 헬링거(Hellinger) 변량을 이용하여 발견된 연속패턴들의 중요도를 측정할 수 있다. 또한 헬링거 변량의 함수적인 특성을 분석하여 연속패턴 추출의 복잡도를 줄이기 위한 두 가지의 법칙이 제안되었다.

• Journal of the Korea Society of Computer and Information
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• v.19 no.8
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• pp.55-62
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• 2014

A game theoretic approach is applied for studying the energy efficient rate scheduling. The individual utility function is defined first. Then, a non cooperative rate game is modeled in which each user decides the transmission rate to maximize its own utility. The utility function considered here is the consumed energy for the individual user's data transmissions. In particular, using the fact that the utility function is convex, we prove the existence of Nash Equilibrium in the energy efficient rate scheduling problem at hand. Accordingly, a non cooperative scheduling algorithm is provided. For better energy efficiency, the sum of the individual user's utility function is optimized Finally, the convergence analysis and numerical results to show the energy efficiency of the proposed algorithms are provided.

• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.133-144
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• 2018

IEC 62278, the Railway System Safety Standard, requires for hazard analysis to prevent or control the hazard that the railway system may have. If hazard analysis is not performed sufficiently, there is a high probability that accidents will occur. For this reason, hazard analysis methods are actively studied. In this paper, we propose the hybrid hazard analysis method to combine two representative hazard analysis methods: reliability-based and system-theoretic. As the proposed method is complementary to existing ones, it covers both the hazard caused by failure of components and the hazard occurred from the unintended control between components. It applies to the development of a safety protection mechanism for multiple cruise control system that automatically control the speed of trains to avoid the collision among trains. As a result, we drive more safety requirements than the existing analysis methods and it turns out that the safety requirements protect the trains with respect to the identified hazards.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.2
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• pp.1-9
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• 1996

Although the fuzzy logic controller (FLC) has been adopted in many engineering applications, one hesitates to adopt the FLC in critical applications, since there was no definite control theoretic analysis. In this paper, based on the stability/robustness analysis of an FLC by S.Y.Yi$^{[3]}$, we apply the FLC to robot manipulator with the structured and unstructured uncertainties e.g., load variation and firction, etc. And we verify the performance of the FLC by computer simulation on a simple two-link robot manipulator.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1670-1673
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• 2002

For pattern recognition on high-dimensional data, such as images, the dimensionality reduction as a preprocessing is effective. By dimensionality reduction, we can (1) reduce storage capacity or amount of calculation, and (2) avoid "the curse of dimensionality" and improve classification performance. Popular tools for dimensionality reduction are Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), and Independent Component Analysis (ICA) recently. Among them, only LDA takes the class labels into consideration. Nevertheless, it, has been reported that, the classification performance with ICA is better than that with LDA because LDA has restriction on the number of dimensions after reduction. To overcome this dilemma, we propose a new dimensionality reduction technique based on an information theoretic measure for difference of distribution. It takes the class labels into consideration and still it does not, have restriction on number of dimensions after reduction. Improvement of classification performance has been confirmed experimentally.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2A
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• pp.133-138
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• 2011

This paper presents an information theoretic outage analysis for physical layer of a cooperative multihop wireless network. Our analysis shows that cooperation by selecting a proper relay at each hop increases the coverage or data rate of the network. In our analysis we consider both symmetric and asymmetric network model. We also investigate the availability of cooperative relay at each hop and show that end-to-end performance of the network depends on the relay selection procedure at each hop. We also verify our analytical results with simulations.

• Advances in nano research
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• v.13 no.2
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• pp.135-146
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• 2022

The accurate assessment of the performance of nonuniform systems requires a thorough understanding of stability analysis. As a result, the theoretical modeling of the influence of various variables on the performance of small-scale nonuniform structures with conventional and non-conventional geometries is presented in this paper. According to the fundamental computer simulation based on mathematical and mechanical principles, the stability of the nonuniform structures is examined. Thus, a numerical procedure is used to simulate the stability and instability characteristics of the nonuniform small-scale structures via computer aid. Theoretic simulation methods provide a great deal of the design and production of small-scale structures at a low cost compared to experimental simulations. Thus, this paper provides a good presentation of the stability analysis of the nonuniform nanoscale structures with high accuracy without actual experimental.

• Journal of Korea Society of Industrial Information Systems
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• v.2 no.1
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• pp.103-123
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• 1997

This dissertation provides a theoretic study on the network security in general , the firewall in particular. In fact the firewall has been recognized as a very promising option to obtain the security inthe real work network environment . The dissertation provides a throuth theoretic investigation on the various problems raised in the computer network, and also explores a methodology of the security against IP spoofing. Moreover, it investigates a systematic procddure to make analysis and plans of the firewall configuration . Based on the above investigation and analysis, this dissertation provides two approaches to network security , which address anumber of issuesboth at the network and at applicatino level. At the network level, a new method is proposed which uses packet filtering based on the analysis of the counter plot about the screen router.On the other hand, at the application level, a novel method is explored which employs secureity software. Firewall-1 , on Bastion host. To demonstrate the feasibililty and the effectiveness of the proposed methodologties , a prototype implementation is made The experiment result shows that the screen router employing the proposed anti-IP spoofing method at the network level is effective enough for the system to remain secure without being invaded by any illegal packets entering form external hackers. Meanwhile , at the application level, the proposed software approach employing Firewall-1 is proved to be robust enugh to prevent hackings from the outer point the point protocal connnection . Theoretically, it is not possible to provide complete security to the network system, because the network security involve a number of issues raised form low level network equipments form high level network protocol. The result inthis dissertation provides a very promising solution to network security due to its high efficiency of the implementation and superb protectiveness from a variety of hacking.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.301-303
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• 1998

This paper presents a new approach to diagnose and detect faults in oil-filled power transformers based on various dissolved gas analyses. A theoretic fuzzy information model is introduced, An inference scheme which yields the 'most' consistent conclusion proposed. A framework is established that allows various dissolved gas analyses to be combined in a systematic way such as the Dempster-Shafer rule. Good diagnosis accuracy is obtained with the proposed approach.