• East Asian mathematical journal
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• v.18 no.1
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• pp.111-125
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• 2002

Many different families of infinite series were recently observed to be summable in closed forms by means of certain operators of fractional calculus(that is, calculus of integrals and derivatives of any arbitrary real or complex order). In this sequel to some of these recent investigations, the authors present yet another instance of applications of certain fractional calculus operators. Alternative derivations without using these fractional calculus operators are shown to lead naturally a family of analogous infinite sums involving hypergeometric functions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.62
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• pp.97-109
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• 2001

This research is concerned with jobshop scheduling problem for an advanced manufacturing system like flexible manufacturing which consists of two machine centers and a single automated guided vehicle(AGV). The objective is to develop and evaluate heuristic scheduling procedures that minimize makespan to be included travel time of AGV. A new heuristic algorithm is proposed and illustrates the proposed algorithm. The heuristic algorithm is implemented for various cases by SLAM II. The results show that the proposed algorithm provides better solutions in reduction ratio and frequency than the previous algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.486-489
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• 1999

This paper deals with the design rule and performance results of the transient voltage blocking devices (TBD) for low-voltage mains on shipboard. The proposed TBD consists of metal oxide varistors (MOV) and L-C filter to improve noise-elimination performance. Three kinds of TBDs are fabricated and tested by using a combination surge generator which can produce the standard impulse current of 8/20${\mu}$s 2.1kA. As a reults, the proposed TBD with series L-C filter has more excellent transient blocking and noise reduction performance than the conventional TBDs.

• Journal of the Korean Vacuum Society
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• v.9 no.1
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• pp.1-6
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• 2000

An unexpected error is produced in calculating the transmission probability of a multipartite duct because of beam and shadow effects, if using a simple summation rule like the Oatley's equation. Particles moving in a tube are directed more or less towards the axis of the tube by the beam effect, and the length of a compound tube shortens virtually by the shadow effect originated from a reduction in the number of particles reaching the corner between two tubes of different cross-sections. Both effects make the transmission probability of the tube connected behind and consequently of the whole duct increase slightly. In this paper sources of the error in the calculation of the transmission probability are analyzed quantitatively and variations in the error depending on the dimensions of cylindrical tubes are calculated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.449-454
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• 2000

A new fuzzy logic control design algorithm suitable for multi-objective control problems is proposed based on the orthogonal array which is widely used for design of experiments in statistics and industrial engineering. The essence of the algorithm is to introduce Nth-certainty factor defined from the F-value of the ANOVA(analysis of variance) table, in order to effectively exclude the less confident rules. The proposed algorithm with multi-objective decision table(MODT) is found to be capable of the detection of inconsistency and the rule classification, reduction and modification. It is also shown that the algorithm can be successfully applied to the fuzzy controller design of an active magnetic bearing system.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.380-383
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• 2015

오용 탐지모델 기반의 침입탐지시스템은 새로운 사이버 공격을 탐지하기 위해 지속적으로 탐지규칙을 생성해야 한다. 공격에 대한 특징을 정확히 식별하지 못하고 탐지규칙을 생성할 경우 많은 false positive를 발생시키며, 이로 인해 침해사고 대응시간이 늦어진다. 본 논문에서는 침입탐지시스템에서 탐지된 이벤트의 true positive와 false positive 데이터를 Keyword Tree의 node에 경로를 지나가는 횟수를 누적하는 값을 포함시킨 자료구조를 기반으로 비교분석하여 false positive를 감소시킬 수 있는 탐지규칙 패턴 생성 기법을 제안한다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.25 no.4
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• pp.162-172
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• 2021

This paper proposes stochastic methods to find an approximate solution for the L²-Wasserstein least squares problem of Gaussian measures. The variable for the problem is in a set of positive definite matrices. The first proposed stochastic method is a type of classical stochastic gradient methods combined with projection and the second one is a type of variance reduced methods with projection. Their global convergence are analyzed by using the framework of proximal stochastic gradient methods. The convergence of the classical stochastic gradient method combined with projection is established by using diminishing learning rate rule in which the learning rate decreases as the epoch increases but that of the variance reduced method with projection can be established by using constant learning rate. The numerical results show that the present algorithms with a proper learning rate outperforms a gradient projection method.

• Geomechanics and Engineering
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• v.17 no.4
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• pp.405-411
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• 2019

A significant influence of the particle size distribution on the resilient behaviour of granular aggregates was usually observed in laboratory tests. However, the mechanisms underlying this phenomenon were rarely reached. In this study, a mechanistic model considering particle breakage is proposed. It is found to be the combined effects of the coefficient of uniformity and the size range between maximum and minimum particle sizes that influences the resilient modulus of granular aggregates. The resilient modulus is found to undergo reduction with evolution of particle breakage by shifting the initial particle size distribution to a broader one.

• Structural Engineering and Mechanics
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• v.87 no.1
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• pp.29-46
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• 2023

Critical thermal buckling of functionally graded porous (FGP) sandwich plates under various types of thermal loading is considered. It is assumed that the mechanical and thermal nonhomogeneous properties of FGP sandwich plate vary smoothly by distribution of power law across the thickness of sandwich plate. In this paper, porosity defects are modeled as stiffness reduction criteria and included in the rule of mixture. The thermal environments are considered as uniform, linear and nonlinear temperature rises. The critical buckling temperature response of FGM sandwich plates has been analyzed under various boundary conditions. By comparing several numerical examples with the reference solutions, the results indicate that the present analysis has good accuracy and rapid convergence. Further, the effects of various parameters like distribution shape of porosity, sandwich combinations, aspect ratio, thickness ratio, boundary conditions on critical buckling temperature of FGP sandwich plate have been studied in this paper.

• The Journal of the Acoustical Society of Korea
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• v.14 no.4
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• pp.89-95
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• 1995

The waveform coding technique has concerned with simply preserving the waveform shape of speech signal through a redundancy reduction process. In the case of speech synthesis, the waveform coding with high sound quality is mainly used to the synthesis by analysis. However, since the parameters of this coding are not classified into either excitation or vocal tract parameters, it is difficult to applying the waveform coding to the synthesis by rule. In order to apply the waveform coding to the synthesis by rule, the pitch alteration technique is required in prosody control. In this paper, we propose a new pitch alteration method that can change the pitch period in waveform coding by scaling the time-axis and compensating the spectrum. This is relevant to the time-frequency domain method were the phase components of the waveform is preserved with a little spectrum distortion of 2.5 % and less for 50% pitch change.