• Structural Engineering and Mechanics
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• 제78권2호
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• pp.209-218
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• 2021

For engineering, there are two major challenges in reliability analysis. First, to ensure the accuracy of simulation results, mechanical products are usually defined implicitly by complex numerical models that require time-consuming. Second, the mechanical products are fortunately designed with a large safety margin, which leads to a low failure probability. This paper proposes an efficient and high-precision adaptive active learning algorithm based on the Kriging surrogate model to deal with the problems with low failure probability and time-consuming numerical models. In order to solve the problem with multiple failure regions, the adaptive kernel-density estimation is introduced and improved. Meanwhile, a new criterion for selecting points based on the current Kriging model is proposed to improve the computational efficiency. The criterion for choosing the best sampling points considers not only the probability of misjudging the sign of the response value at a point by the Kriging model but also the distribution information at that point. In order to prevent the distance between the selected training points from too close, the correlation between training points is limited to avoid information redundancy and improve the computation efficiency of the algorithm. Finally, the efficiency and accuracy of the proposed method are verified compared with other algorithms through two academic examples and one engineering application.

• Advances in Energy Research
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• 제2권2호
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• pp.61-72
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• 2014

This paper's aim is to do a global evaluation (considering four dimensions: technical-economic, environmental, social and political) in the ways of natural gas transportation (gas pipelines, GNL and GTL) and electric transmission, in order to supply the energy demands of Mato Grosso do Sul, a brazilian state. The transport ways had been compared between itself using a software of decision taking (Decision Lens Suite), which determined a better way for transporting natural gas in this case. In a generalized manner the gas pipeline is the best way of transporting natural gas, therefore it takes advantage in the majority of the analyzed dimensions.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.294-299
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• 2008

Nowadays there are numerous factors to design the structure even for simple one, but many parts of the work are similar to the existing or repeated simply. In this case, design of the structure is unnecessarily needed lots of effort and time. To solve difficulties of design, an integrated design automation system for retaining wall structures that widely used is developed. The automation system consists of following items, 1) XML data structure between modules, 2) CAD visualization system to provide drawing sheets, 3) excel solution to provide structural design sheets and bills of quantity, 4) design logic to analysis and calculate behaviors of structure, and 5) GUI to represent data and results for the program.

• 전기학회논문지P
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• 제64권4호
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• pp.281-285
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• 2015

Electrical energy supply interruption degrades reliability of power supply as well as social costs and economic loss. It is important to assess the reliability of the power system. Nowadays IEC61850 based substation automation system(SAS) has been developed for an updating of automation and interoperability. In this study, three kinds of reliability block diagram(RBD) were proposed to examine of network availability of the three types SAS. And reliability and unreliability of the SAS was formulated using the RBD. Finally, while varying the value of reliability and unreliability, the reliability and the unreliability of the overall system were evaluated.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.425-436
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• 2016

In this paper, a parameter optimization based iterative learning control strategy is presented for permanent magnet synchronous motor control. This paper analyzes the mechanism of iterative learning control suppressing PMSM torque ripple and discusses the impact of controller parameters on steady-state and dynamic performance of the system. Based on the analysis, an optimization problem is constructed, and the expression of the optimal controller parameter is obtained to adjust the controller parameter online. Experimental research is carried out on a 5.2kW PMSM. The results show that the parameter optimization based iterative learning control proposed in this paper achieves lower torque ripple during steady-state operation and short regulating time of dynamic response, thus satisfying the demands for both steady state and dynamic performance of the speed regulating system.

• 한국통신학회논문지
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• 제19권2호
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• pp.202-210
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• 1994

본 논문에서는 Flexible Automation을 위한 네트워크 운영과 관리체제를 분석하고 이에따른 요구사항을 고려하여 네트워크 관리 시스템을 설계하였다. 네트워크 관리기능은 자원을 제어하고 관리하는 필수적인 기능으로, 관리 서비스를 제공할 수 있는 방법과 관리구조를 제안하고 해석적 방법과 큐잉모델을 이용하여 전송 데이터의 증가에 따른 지연시간 분포를 구하고 성능을 분석한다. 성능관리를 위한 성능을 측정하고 그 결과를 분석하여 설계된 관리시스템의 운영에 대한 타당성을 확인하였다.

• 품질경영학회지
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• 제24권3호
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• pp.1-18
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• 1996

The purpose of this study is to empirically examine the role of supplier relationships as a means of enhancement of quality. The model for this study consists of four groups of concepts - 1) goal of quality, as 2) measures of supplier relationships, supplier assistance and buyer supplier communication, 3) the level of automation and technology, as 4) measures of performance, reliability quality and performance quality. By statistical analysis, the results are as follows. First, the goal of quality positively influences the level of automation, technology, supplier assistance and supplier communication. Second, the level of technology has a positive effect on supplier assistance and supplier communication on the level of automation. Third, the level of automation and technology positively influence the reliability quality. Fourth, supplier assistance and buyer-supplier communication has a positive effect on the reliability and performance quality. These results reveal three paths of supplier relationships in systems for the enhancement of quality.

• Journal of Power Electronics
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• 제18권3호
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• pp.672-680
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• 2018

A bidirectional exponential-gain switched-capacitor (SC) DC-DC converter is developed in this paper. When compared with existing exponential SC converters, the number of switches is significantly reduced and its structure is simplified. The voltage transfer features, voltage ripple across capacitors, efficiency and output impedance of the proposed converter are analyzed in detail. Optimization of the output impedance is also discussed and the best type of capacitance distribution is determined. A common function of the voltage gain to the output impedance is found among the proposed converter and other popular SC voltage multipliers. Experimental evaluation is carried out with a 6-24V bidirectional prototype converter.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권3호
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• pp.260-268
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• 2013

Based on classical Berotti discrete iron loss calculation model, the iron loss analysis mathematical model of alternator was proposed in this paper. Considering characteristics of high speed and changing frequency of the alternator, Maxwell 3-D model was built to analyze iron loss corresponding to each running speed in alternator. Based on iron loss model of alternator at rated speed, the rotor claw pole size was made an optimization design. The optimization results showed that alternator's output performance had been improved. A new idea was explored in size optimization design of claw pole alternator.

• 한국지리정보학회지
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• 제2권1호
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• pp.63-72
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• 1999

본 논문에서는 OLE 자동화를 이용한 GIS의 사용자 인터페이스를 개발하는 방법을 제시하였다.사용자 인터페이스의 개발에 있어서는 윈도우즈 프로그래밍 기술과 컴포넌트 소프트웨어 제작 기술의 적용이 중요하다. 본 논문에서는 컴포넌트 소프트웨어 제작 기술인 OLE 자동화와 비주얼 베이직 언어를 이용하여 사용자 인터페이스를 개발하는 방법을 제시하고, 사례 연구로서 주제도 중첩, 속성 테이블 조회, 그래프 분석, 분포도 분석 등의 기능을 수행할 수 있는 사용자 인터페이스를 개발하였다.