• 대한산업공학회지
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• 제33권2호
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• pp.227-236
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• 2007

This paper proposes a method for designing stacking warehouses of pyramid type which can be found in storage rooms for steel coils, paper rolls, and drums for oils. Formulas were derived for estimating the expected travel time of cranes and the expected time for rehandling activities. Based on the derived formulas, this study derives the cost function for determining the optimal numbers of rows, bays, tiers of stacks under the condition that the requirement for storage space is satisfied. Numerical examples were given.

• 대한화학회지
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• 제57권2호
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• pp.172-175
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• 2013

We compare the relative usefulness of common basis functions and numerical integration methods in representing complex resonance state encountered in the molecular scattering problem of aluminum dimer electronic predissociation. Specifically, the basis set size and computing CPU times are monitored in order to find the minimum requirement for ensuring the modest accuracy of calculated resonance energies (0.1 $cm^{-1}$) for more than 100 resonance states. The combination of the so-called one-dimensional box eigenfunctions and energy-dependent boundary functions are found to be most efficient if integration is done using the basis set quadrature rules.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.353-354
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• 2017

본 연구에서는 전압승압형 컨버터로 동작하는 부스트 컨버터의 최적 제어기법에 대해 서술한다. 부스트 컨버터를 상태평균화 모델을 이용하여 전달함수를 구한 다음, Root Locus와 Bode Plot을 이용하여 시스템 요구사항(Requirement)을 만족시키는 제어기 설계 방법을 제안한다.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2004년도 춘계학술발표대회논문집
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• pp.326-329
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• 2004

Content adaptation is an effective solution to support the quality of service over multimedia services over heterogeneous environments. This paper deals with the accuracy and the real-time requirement, two important issues in making decision on content adaptation. From our previous problem formulation, we propose an optimal algorithm and a fast approximation based on the Viterbi algorithm of dynamic programming. Through extensive experiments, we show that the proposed algorithms can enable accurate adaptation decisions, and especially they can support the real-time processing.

• Korean Chemical Engineering Research
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• 제52권5호
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• pp.581-586
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• 2014

하수처리장을 운영함에 있어 안정적인 방류수질 확보와 이에 따른 처리 비용을 최소화하는 것이 주요 목적이다. 하지만 유입수 유량 및 성분 농도의 변화와 미생물의 비선형적인 동특성, 기타 환경 요인에 의해서 최적의 운전 제어를 하기가 쉽지 않기 때문에, 기존의 하수처리장에서는 필요한 양 이상의 폭기 및 화학물질을 과량 주입하는 방법 등을 사용하였다. 본 연구에서는 포기조에서 미생물에 필요한 용존산소농도는 유지하면서 과폭기로 인한 전력 비용을 감소하는 최적 제어 방법을 제안하였다. 하수조성와 포기조 미생물의 호흡률은 실시간 미생물 호흡률 측정기(Oxygen uptake rate, OUR)를 이용하여 측정하였고, 실시간 호흡률 측정값을 바탕으로 현재 미생물에 필요한 최적 DO 농도를 제안하였다. 유입수 부하변동에 따라 변화하는 미생물 호흡에 필요한 산소량 만큼만 폭기하도록 구성함으로써, 방류수 수질기준을 만족함과 동시에 전력 비용을 최소화할 수 있는 방안을 제시하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.190-195
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• 1997

The requirement of precision products about difficult-to-cut materials such as Cu and Aluminum alloy is becoming more and more. Because of soft materials, the exist narrow groves on surface are difficult to gotten off even on the polishing stage. It has been proved that Magnetic-Electrolytic-Abrasive Polishing (MEAP) is a efficient method to resolve this problem by using the nonwoven-abrasive pads together [1, 2]. In this study, through the experiments, their machining properties of newly developer polishing material of SiC, Al2O3 and diamond nonwoven abrasive pads have been proved. Through the experiments, the optimal machining conditions on larger cylinder shape workpiece of Cu and Aluminium alloy have been found, through the Taguchi[3] method the optimal machining conditions can be selected.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.51-58
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• 2006

In rapid prototyping, the optimal part orientation during fabrication is critical as it can improve part accuracy, minimize the requirement for supports and reduce the production time. Through investigating the geometric issues of STL model and process planning of RPM, This paper establishes optimizing model based on the considerations of staircase effect, support area and production time. The general satisfactory degree function is constructed employing the multi-objective optimization theory based on the general satisfactory degree principle. The best part-building orientation is obtained by solving the function employing generic algorithm. Experiment shows that the methods can effective resolve the part-building orientation in RP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1006-1007
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• 2015

Recent improvement in semiconductor technology make efficient switching possible at higher frequencies, which benefits the application of wireless inductive energy transfer. However, a higher frequency does not alter the magnetic coupling between energy transmitter and receiver. Due to the still weak magnetic coupling between transmitting and receiving sides that are separated by a substantial air gap, energy circulates in the primary transmitting side without being transferred to the secondary receiving side. This paper proposes an analysis on the system efficiency to determine the optimal impedance requirement for coils, rectifier and DC-DC Converter. A novel Boost DC-DC Converter is designed to provide the optimal impedance matching in WPT(Wireless Power Transfer) system for various loads.

• Journal of Communications and Networks
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• 제16권5호
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• pp.559-567
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• 2014

In this paper, a framework for power allocation of downlink transmissions in orthogonal frequency division multiple access-based decode-and-forward cellular relay networks is investigated. We consider a system with a single base station communicating with multiple users assisted by multiple relays. The relays have limited power which must be divided among the users they support in order to maximize the data rate of the whole network. Advanced power allocation schemes are crucial for such networks. The optimal relay power allocation which maximizes the data rate is proposed as an upper bound, by finding the optimal power requirement for each user based on knapsack problem formulation. Then by considering the fairness, a new relay power allocation scheme, called weighted-based scheme, is proposed. Finally, an efficient power reallocation scheme is proposed to efficiently utilize the power and improve the data rate of the network. Simulation results demonstrate that the proposed power allocation schemes can significantly improve the data rate of the network compared to the traditional scheme.

• 한국유체기계학회 논문집
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• 제13권6호
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• pp.19-24
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• 2010

The demands for small, high performance and high loaded aircraft compressor are increased in the world. But the design requirements become increasingly complex to design these high technical engines, the requirement of the design optimization become increased. The optimal design result of several disciplines show different tendencies and nonlinear characteristics of the compressor design, the multidisciplinary design optimization method must be considered in compressor design. Therefore, the artificial Neural Net method is adapted to make the approximation model of 3-stage axial compressor design optimization for considering the nonlinear characteristic. At last, the optimal result of this study is compared to that of previous study.