• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.669-678
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• 2007

An algorithm to detect the number of discontinuity points of the variance function in regression model is proposed. The proposed algorithm is based on the left and right one-sided kernel estimators of the second moment function and test statistics of the existence of a discontinuity point coming from the asymptotic distribution of the estimated jump size. The finite sample performance is illustrated by simulated example.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.689-696
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• 2007

This paper considers a Bayesian approach to determine an optimal PM policy with random maintenance quality. Thus, we assume that the quality of a PM action is a random variable following a probability distribution. When the failure time is Weibull distribution with uncertain parameters, a Bayesian approach is established to formally express and update the uncertain parameters for determining an optimal PM policy. Finally, the numerical examples are presented for illustrative purpose.

• Journal of the Korean Data and Information Science Society
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• v.25 no.5
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• pp.1107-1116
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• 2014

In this paper, we review recent developments in network analysis using the graph theory, and introduce ongoing research area with relevant theoretical results. In specific, we introduce basic notations in graph, and conditional and marginal approach in constructing the adjacency matrix. Also, we introduce the Marcenko-Pastur law, the Tracy-Widom law, the white Wishart distribution, and the spiked distribution. Finally, we mention the relationship between degrees and eigenvalues for the detection of hubs in a network.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.51-53
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• 2000

기존의 진화 연산의 한계를 극복하기 위해서 탐색점 분포 학습 알고리즘(Estimation of Distribution Algorithm)이 부각되고 있다. 탐색점 분포 학습 알고리즘은 데이터의 분포를 파악하고, 파악된 분포를 이용해서 새로운 학습 데이터를 생성하는 일련의 과정을 통하여 최적화 문제를 해결하는 방법이다. 그런데, 기존의 탐색점 분포 학습 알고리즘들은 대부분 이진 벡터값을 가지는 최적화 문제들만을 대상으로 하고 있다. 본 논문에서는 비감독 확률 신경망 모델인 헬름홀츠 머신을 이용해서 데이터의 분포를 학습하여 연속 함수 최적화 문제를 해결하는 방법을 개발하였다. 테스트 함수들에 대해서 실수 표현형을 사용한 유전자 알고리즘과 결과를 비교하여 제안하는 방법의 우수성을 검증하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1240-1243
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• 2016

In this paper, we analyze the queueing performance of cumulative distribution function (CDF)-based opportunistic scheduling over Nakagami-m Markov fading channels. We derive the formula for the average queueing delay and the queue length distribution by constructing a two-dimensional Markov chain. Using our formula, we investigate the queueing performance for various fading parameters.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2722-2727
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• 1999

In this paper we propose verifiable self-certified identification and key distribution protocols which has advantages of certificate-based scheme and Girault's self-certified public key. The security of the proposed protocols is based on ${\gamma}$\ulcorner-residuosity problem and discrete logarithm problem.

• Annual Conference of KIPS
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• 2018.05a
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• pp.219-221
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• 2018

테스팅에서 발견하지 못한 결함은 시스템 운용 중 막대한 영향을 미친다. 국방에서 실시간 정보의 공유는 신속한 지휘결심과 임무능력으로 이어진다. 잠수함 분산 데이터 시스템(Data Distribution System)은 함의 운용술과 관련된 중요한 시스템 중 하나이므로, DDS의 데이터 연동 특성을 분석하고 효율적인 연동테스트 기법을 제시한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.2
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• pp.21-30
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• 2000

본 논문에서는 이동통신환경의 특징과 기존의 키분배 프로토콜들에서 발생할 수 있는 공격들을 프로토콜 수행전 수행중, 수행후로 나누어서 살펴보고 이를 기반으로 이동통신환경에 적합한 키분배 프로토콜 설계에 필요한 요구사항 들을 제시한다 또한 제시된 요구사항을 기반으로 이동통신환경에 적합한 상호인증을 제공하는 키분배 프로토콜을 제안하고 제안한 프로토콜을 분석한다.

• The Journal of Industrial Distribution & Business
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• v.8 no.1
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• pp.33-39
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• 2017

Purpose - The main purpose of the current study is to examine the impact of accounting information quality and information asymmetry on the underinvestment phenomenon among the listed companies on the Tehran Stock Exchange (TSE). Research design, data, and methodology - The population includes 94 firms selected through systematic sampling. The data is collected from the audited financial statements of the firms provided by TSE's website from 2010 to 2015. Accounting information quality and information asymmetry is considered as independent variables, and their impact is examined on the dependent variable (underinvestment). Results - The statistical results, based on data collected from 94 listed companies on the TSE during 2010-2015, revealed positive impact of accounting information quality and positive impact of information asymmetry on underinvestment. There was a significant relationship between accrual quality (AQ) and underinvestment, and spread and underinvestment. The results also showed that information asymmetry is the main factor in the creation underinvestment. Conclusions - Findings of this article can assist accounting researchers and theoreticians in comparing Real world facts with hypotheses developed with respect to accounting information quality, information asymmetry and underinvestment. However, the results of fuzzy regression analysis indicate significant relationships between the independent variable except underinvestment.

• Journal of the Korea Safety Management & Science
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• v.4 no.1
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• pp.105-114
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• 2002

Nowadays, most companies seek after the greatest profit by means of offering the goods which consumers want timely and efficiently and minimizing the cost of inventory and distribution channel which amounts to the great portion of total cost. And according as EC(Electronic Commerce) market has increased rapidly, SCM(Supply Chain Management) for EC become one of the most important facts for companies, therefore this paper suggest SCM scheme which EC, especially B to C, is added to the existing commerce system. This paper uses internet for information integration of distribution channel which is away from one another and applies TOC(Theory of Constraint)'s DBR(Drum-Buffer-Rope) Scheduling for synchronization through the whole supply chain. It is possible to synchronize the whole supply chain by means of making the speed of manufacturing and distribution to be controlled by consumer's order which is received in distribution center, and inventory and loss of sales opportunities are minimized by constant. Buffer Management. If inventories in distribution center is short, then it needs to search CCR(Capacity Constraint Resource) in supply chain and to control the speed of manufacturing and distribution according to the ability of CCR. This paper applies PT(Partial Transshipment) strategy for Delivery from distribution center to store or cyber consumer. the strategy this paper suggests chooses neighbour area from area which each distribution center takes charge, and then makes product ordered by cyber consumer which lives in the chosen area to be delivered according to inventory of distribution center.