• KIEAE Journal
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• 제15권4호
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• pp.105-110
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• 2015

Purpose: This study aimed at finding the optimal input variables of the artificial neural network-based predictive model for the optimal controls of the indoor temperature environment. By applying the optimal input variables to the predictive model, the required time for restoring the current indoor temperature during the setback period to the normal setpoint temperature can be more precisely calculated for the cooling season. The precise prediction results will support the advanced operation of the cooling system to condition the indoor temperature comfortably in a more energy-efficient manner. Method: Two major steps employing the numerical computer simulation method were conducted for developing an ANN model and finding the optimal input variables. In the first process, the initial ANN model was intuitively determined to have input neurons that seemed to have a relationship with the output neuron. The second process was conducted for finding the statistical relationship between the initial input variables and output variable. Result: Based on the statistical analysis, the optimal input variables were determined.

• 대한토목학회논문집
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• 제13권2호
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• pp.295-305
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• 1993

본 연구의 목적은 오염 심화된 하천 수질개선을 위한 희석수량 및 점오염원을 최적 제어할 수 있는 수질관리 시스템개발에 대한 이론적 방법론을 연구하는데 있다. 시스템 제어변수로는 하천 유하량과 처리장 방출수의 농도수준을, 상태변수로는 DO, BOD, COD, SS를 선택하였고, 시스템 해법으로는 비선형기법인 augmented Lagrangian 기법을 활용하였다. 개발된 시스템을 검증하기 위한 적용대상 하천으로는 오염 심화된 도시하천인 무심천을 선정하였다. 검증과정으로 부터, 개발된 방법론은 도시하천 뿐만아니라 수계 전반에 걸친 폭넓은 분석에도 적합할 것으로 사료되었으며, 제한된 수자원의 효율적 운영을 위한 방안을 제시하는데도 유용한 도구가 될 수 있을 것으로 판단되었다.

• 대한기계학회논문집A
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• 제30권8호
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• pp.1001-1007
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• 2006

In this paper we present robust optimal supporting positions for large glass panels used for TFT-LCD monitors when they are stored in a cassette during manufacturing process. The criterion taken is to minimize their maximum deflection. Since they are supported by some supports and have large deformations, contact analysis with a geometrically nonlinear effect is necessary. In addition, the center of a panel can not be positioned exactly as intended and should be considered as uncertainties. To take into account of these effects, the mean and the standard deviation of system response functions, particularly the deflection of the panels, need be calculated. A function approximation moment method (FAMM) is utilized to estimate them. It is a special type of response surface methodology for structural reliability analysis and can be efficiently used to estimate the two stochastic properties, that is, the system performance and the perturbations caused by uncertainties. For a design purpose, they are to be minimized simultaneously by some optimization algorithm to obtain robust optimal supporting positions.

• 한국기계가공학회지
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• 제11권1호
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• pp.26-32
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• 2012

Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This study will report the characteristic of wafer according to processing time, machining speed and pressure which have major influence on the abrasion of Si wafer polishing. It is possible to evaluation of wafer abrasion by load cell and infrared temperature sensor. The characteristic of wafer surface according to processing condition is selected to use a result data that measure a pressure, machining speed, and the processing time. This result is appeared by the characteristic of wafer surface in machining condition. Through that, the study cans evaluation a wafer characteristic in variable machining condition. It is important to obtain optimal condition. Thus the optimum condition selection of ultra precision Si wafer polishing using load cell and infrared temperature sensor. To evaluate each machining factor, use a data through each sensor. That evaluation of abrasion according to variety condition is selected to use a result data that measure a pressure, machining speed, and the processing time. And optimum condition is selected by this result.

• 대한기계학회논문집A
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• 제28권7호
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• pp.1038-1046
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• 2004

In order to acquire high-speed and high-precision performances in servomechanisms, an integrated design method have been proposed. Based on strict mathematical modeling and analysis of system performance according to design and operating parameters, a nonlinear constrained optimization problem including the relevant subsystem parameters of the servomechanism is formulated. Optimum design results of mechanical and electrical parameters are obtained according to the design parameters specified by designers through the integrated design processes. Motors are optimally selected from the servo motor database. Both the geometric errors referring to Abbe offset and the contour errors are minimized while required constraints such as stability conditions and saturated conditions are satisfied. This design methodology both offers the improved possibility to evaluate and optimize the dynamic motion performance of the servomechanism and improves the quality of the design process to achieve the required performance for high-speed/precision servomechanisms.

• 한국정밀공학회지
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• 제24권2호
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• pp.118-126
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• 2007

Most of materials receive forces in use so that the characteristics of materials must be considered in system design to prevent deformation or destruction. Mechanical properties of materials can be expressed as responsible level of material itself under the exterior operation. Main mechanical properties are strength, hardness, ductility and stiffness. Currently, among major measure facilities to measure the mechanical properties, advanced indentation technique has important use in industrial areas due to nondestructive and easy applications for mechanical tensile properties and evaluation of residual stress of materials. This study is to find the optimum experimental condition about residual stress advanced indentation technique for accurate analysis of the welded joint of steel materials through indentation load-depth curve obtained from cruciform specimen experiment. Optimum selection was applied to the welded joint of real steel materials to find out non-equi-biaxial stress state and the results were compared with general residual stress analyzing method fur verification.

• 한국공작기계학회논문집
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• 제17권6호
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• pp.43-48
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• 2008

This study includes contents on an effective designing of the outer-wall piece removing equipment of a hull, by applying TRIZ. To remove the piece, gas torch was used. However, the heat source must be shut down since the heat source of gas torch has a bad influence on this system. This is why TRIZ and Brainstorming were used, to solve this problem. First, we analyzed the system using TRIZ, and then presented the direction a solution is expected to follow. And the most suitable scheme was derived from brainstorming which had been conducted based on the direction of a solution. Lastly we conducted an equipment modeling based on the most suitable scheme we made before, and carried out the heat analysis to inspect its effect by comparing pre-existing mechanism with most suited scheme.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 1호
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• pp.351-355
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• 1999

서비스 반경이 1이내인 마이크로셀 방식은 기지국의 송신출력을 가능한 작게 하고 안테나의 위치를 주변 건물의 높이보다 낮게 설치하기 때문에 셀 반경내에 있는 지형과 구조물들은 전파특성에 매우 큰 영향을 주므로 셀 내 지형지물의 특성에 따라 기지국의 최적 출력을 구할 수 있는 전파예측 모델이 필요하다. 본 연구에서는 이동국이 가시거리 영역의 전파 음영지역 또는 가시거리 영역과 일정 경사각으로 기울어져 있는 비가시거리 영역에 위치한 경우로 구분하고, 기지국으로부터 송신된 신호가 이동국까지 일정 직진경로를 전파하는 동안, 전파의 반사첫수와 전파경로를 계산할 수있는 연산처리 알고리즘을 개발하여, 이를 웅용하므로써 임의 지점에 위치한 이동국에 도래하는 수신전력을 예측할수 있는 모델을 제안한다. 그리고, 마이크로셀 이동통신 전파환경에서 개발 알고리즘과 제안 전파예측 모델을 시뮬레이션하여, 그 결과를 분석함으로써 마이크로셀 기지국의 최적 위치선정 조건과 기지국 출력에 따른 가입자 서비스 조건을 제시한다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.529-533
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• 2012

By introducing RPS(Renewable Portfolio Standard) for reduction of greenhouse gas, Renewable energy sources have becoming widespread gradually. However, Renewable energy sources, such as wind power and PV are difficult to control the output and they have intermittent characteristics of the output. These characteristics would cause some problems when it is connected in the power system. In order to solve these problems, Energy Storage Systems(ESS) are considered to use. Although there are many different storage devices, the utilization of Secondary Battery is the one of the best ways to stabilize an output fluctuation of RES because of its fast responsibility. For that reason, it would better fit a large-capacity of Secondary battery for stabilization. However, batteries cannot be installed with a large capacity blindly because of its expensive cost. So to select proper capacity of the battery is an important consideration. This paper presented a methodology for the optimal capacity and operation of ESS in microgrids.

• 한국철도학회논문집
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• 제14권3호
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• pp.228-233
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• 2011

본 논문에서는 한국의 지하철역명을 위하여 음운론적 특성을 반영한 음소 기반의 음성인식 구현에 관한 방법을 제시하였다. 한국의 지하철역명의 음소 기반의 음성인식을 위하여 사용되는 최적의 유사음소 단위(PLU: Phoneme-Likely Unit)를 선정하기 위하여 네 가지의 Case 별로 PLU set과 음운 현상을 고려한 발음사전을 구성하여 인식률을 평가하였다. 적용된 유사음소 단위의 경우 초성과 종성 자음의 인식 단위 구분 및 음운 현상을 반영한 경우 트라이폰 모델에서 최적의 인식률(97.74%)을 보임을 알 수 있었다.