• 전자공학회논문지
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• 제50권7호
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• pp.275-280
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• 2013

본 논문은 무선 충전 시스템의 최적화 기법에 대한 것으로서, 특히 캡슐형 내시경 응용을 위한 회로를 기반으로 한다. 이 논문에서는 저용량 배터리를 내장하는 무선 충전 시스템에서 전자기 유도 원리를 이용한 방식을 적용하여 배터리 용량을 필요 이상으로 증가시키지 않는 상태에서 여러 가지 상황에 대응하여 무선 전력 전송의 효율을 최적화하는 것을 목표로 하였다. 전자기 공진 코일의 무선 전력 전송의 효율을 증가시키기 위하여 전력 전송의 주요 결정 요소를 분석하고 주파수 제어에 의한 효율 최적화를 시도하였다. 모의실험 결과 제안된 최적화 기법은 무선 충전 효율을 안정화시키고 현재 문제가 되고 있는 거리 및 기생 성분에 의한 전송 효율 변이를 효과적으로 개선하는 것을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.109-114
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• 2012

In this paper, we utilize training strategy of hidden Markov model (HMM) to use in versatile issues such as classification of time-series sequential data such as electric transient disturbance problem in power system. For this, an automatic means of optimizing HMMs would be highly desirable, but it raises important issues: model interpretation and complexity control. With this in mind, we explore the possibility of using genetic algorithm (GA) and harmony search (HS) algorithm for optimizing the HMM. GA is flexible to allow incorporating other methods, such as Baum-Welch, within their cycle. Furthermore, operators that alter the structure of HMMs can be designed to simple structures. HS algorithm with parameter-setting free technique is proper for optimizing the parameters of HMM. HS algorithm is flexible so as to allow the elimination of requiring tedious parameter assigning efforts. In this paper, a sequential data analysis simulation is illustrated, and the optimized-HMMs are evaluated. The optimized HMM was capable of classifying a sequential data set for testing compared with the normal HMM.

• International Journal of Control, Automation, and Systems
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• 제4권5호
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• pp.601-614
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• 2006

In this paper, a study on task assignment strategies for a complex real-time network system is presented. Firstly, two task assignment strategies are proposed to improve previous strategies. The proposed strategies assign tasks with meeting end-to-end real-time constraints, and also with optimizing system utilization through period modulation of the tasks. Consequently, the strategies aim at the optimizationto optimize of system performance with while still meeting real-time constraints. The proposed task assignment strategies are devised using the genetic algorithmswith heuristic real-time constraints in the generation of new populations. The strategies are differentiated by the optimization method of the two objectives-meeting end-to-end real-time constraints and optimizing system utilization: the first one has sequential genetic algorithm routines for the objectives, and the second one has one multiple objective genetic algorithm routine to find a Pareto solution. Secondly, the performances of the proposed strategies and a well-known existing task assignment strategy using the BnB(Branch and Bound) optimization are compared with one other through some simulation tests. Through the comparison of the simulation results, the most adequate task assignment strategies are proposed for some as system requirements-: the optimization of system utilization, the maximization of running tasktasks, and the minimization of the number of network node nodesnumber for a network system.

• 대한안전경영과학회지
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• 제14권4호
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• pp.177-184
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• 2012

Logistics cost of domestic company has been improved continuously and annually, it is still higher than other main comparative countries. So, in this study, as optimizing the logistic network of distribution, it was trying to find methods decreasing logistics cost and storage cost, which occupies 86% of logistics cost of companies. through the efficiency of transportation and delivery routing, it could be also possible to decrease the logistics cost. And, it is also checked to find the logistics cost could be decreased by 10% by optimizing the routes of transportation and delivery, improving the transportation mode, etc.

• 정보처리학회논문지B
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• 제14B권2호
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• pp.127-134
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• 2007

기계 학습 등 인공 지능 기법의 발전에 힘입어 지능형 주식 거래 시스템에 관한 많은 연구가 이루어져 왔다. 그러나 현실 주식 거래에서 적절한 거래 정책의 수립이 거래의 결과에 커다란 영향을 미치는 중요 요소로 작용하고 있음에도 불구하고, 기존의 연구에서는 예측 모듈의 예측 성능 향상에 주력하였거나, 거래 정책을 다룬 경우라도 예측 모듈에 종속적인 단순한 정책만을 제시하였다. 본 논문에서는 이러한 문제를 개선하기 위한 방안의 하나로, 신경망 기반 주식 거래 시스템의 구축을 위한 통합 개발 도고인 NXShell에서 채택하고 있는 ‘통합 다중 시뮬레이션‘ 기법을 제안한다. 통합 다중 시뮬레이션 기법에서는 신경망의 출력 값과 거래 정책 인자들 간의 모든 주어진 예측기의 특성에 맞는 고유의 최적 거래 정책을 수립한다. 제안된 기법의 효용성을 검증하기 위해, 한국 거래소 시장 및 코스닥 시장에서 수집한 데이터를 사용하여 수행한 거래 성능 비교 실험 결과를 제시한다.

• International Journal of Automotive Technology
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• 제7권7호
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• pp.841-846
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• 2006

This paper presents a numerical approach to optimizing vehicle fuel economy in a higway bus. The method described is based on using a commercial software vehicle simulation to identify the relative efficiency of each of the vehicle systems, such as the engine hardware, engine software calibration, transmission, cooling system and ancillary drives. The simulation-based approach offers a detailed understanding of which vehicle systems are underperforming and by how much the vehicle fuel economy can be improved if those systems are brought up to best-in-class performance. In this way, the optimum vehicle fuel economy can be provided to the vehicle customer. A further benefit is that the simulation requires only a minimum number of vehicle testing for initial validation, with all subsequent field test cycles performed in software, thereby reducing development time and cost for the manufacturer.

• 조명전기설비학회논문지
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• 제29권4호
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• pp.30-36
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• 2015

The principle of an illumination and projection system including LED light sources for a spot type stage lighting system was presented, and its optical system was designed with optimizing parameters by the analytical methods. A dichroic mirror incorporated with an illumination system to optimizing LED source positions and to obtain the compact system. The projection system was optimized with specific constraints such as a chromatic aberration, distortion aberration and angle of incidence angles. Optimized design system has a beam angle from $10^{\circ}$ to $45^{\circ}$, and its illuminance was 4,500lux at distance of 6m on the work plane.

• 대한산업공학회지
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• 제12권1호
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• pp.107-118
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• 1986

A heuristic algorithm (SIMICOM) has been designed and tested for optimizing simulated stochastic systems whose performances are functions of several discrete decision variables. The approach adopted utilizes an integer complex method coupled with techniques of establishing confidence intervals for the system's responses. It can handle a general class of optimization problems that could be constrained or unconstrained. In constrained cases, the constraints could either be explicit analytical functions of decision variables or be expressed as other responses of the simulation model. In addition to obtain a reasonably accurate solution, the economic aspect of obtaining the solution has also been taken into consideration.

• 한국기계가공학회지
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• 제14권1호
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• pp.36-43
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• 2015

Optimizing multiple design characteristics which are usually in conflict with each other in the injection molding process is frequently becoming a critical problem for designers who work in this area. The purpose of this work is to develop an automated design methodology for optimizing two such design characteristics found in injection-molded parts. A value function based on decision-making theory is used as a means of evaluating the performance of a two-characteristic design alternative. Also, a design space reduction algorithm based on Taguchi's orthogonal arrays is utilized to discover an optimal design alternative. Verification of the developed design methodology is carried out for an actual model with two design characteristics, the weld line and the gate location, to be optimized in computer simulation experiments.

• 한국기계가공학회지
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• 제8권3호
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• pp.90-97
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• 2009

In the study, a design methodology for robust minimization of a warpage in injection-molded part is presented. Taguchi's parameter design method is integrated with a computer simulation tool for injection molding to search for best design with robustness against the process variability by noises. The proposed methodology is based on a two-stage process: (1) reducing a warpage in the part by optimizing the part geometry including the layout and size of ribs, and (2) additionally minimizing the warpage by optimizing process conditions. An example is used to illustrate the usefulness of the design methodology.