• 대한전기학회논문지:전력기술부문A
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• 제55권1호
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• pp.1-6
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• 2006

The emergence of competitive power market makes dispatch algorithm with transient stability constraints increasingly important for the transparent power system operation. Heuristic and off-line evaluation for the operation point can produce a discrimination among market players in the deregulated power system. In this paper, a dispatch algorithm with transient stability constraints is proposed. Energy margin under the TEF(Transient Energy Function) structure is adopted as a measure for the stability index. Implementation issues and simulation results are discussed in the context of a 10-bus system

• 전기학회논문지P
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• 제54권2호
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• pp.67-72
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• 2005

This paper presents a method to select contingency ranking considering voltage security problems in power systems. Direct method which needs not the detailed knowledge of the post contingency voltage at each bus is used. Based on system operator's experience and knowledge, the membership functions for the MVAR mismatch and allowable voltage violation are justified describing linguistic representation with heuristic rules. Rule base is used for the computation of severity index for each contingency by fuzzy inference. Contingency ranking harmful to the system is formed by the index for security evaluation. Compared with 1P-1Q iteration, this algorithm using direct method and fuzzy inference shows higher computation speed and almost the same accuracy. The proposed method is applied to model system and KEPCO pratical system which consists of 311 buses and 609 lines to show its effectiveness.

• 대한안전경영과학회지
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• 제4권4호
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• pp.97-108
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• 2002

This study deals with the application of knowledge-based engineering and a methodology for the assessment & measurement of reliability, availability, maintainability, and safety of industrial systems using fault-tree representation. A fuzzy methodology for fault-tree evaluation seems to be an alternative solution to overcome the drawbacks of the conventional approach. To improve the quality of results, the membership functions must be approximated based on heuristic considerations. Conventionally, it is not always easy to obtain a system reliability for components with different individual failure probability density functions(p.d.f.), We utilize fuzzy set theory to solve the adequacy of the conventional probability in accounting and processing of built-in uncertainties in the probabilistic data. The purpose of this study is to propose the framework of knowledge-based engineering through integrating the various sources of knowledge involved in a FTA.

• 대한산업공학회지
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• 제15권1호
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• pp.105-116
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• 1989

This study presents an algorithm that determines the optimal configuration of the FMSs with limited local buffers. The algorithm finds the lowest cost configuration, i.e. the number of tools, the number of pallets as well as the number of buffers to be installed in front of each machine in the system. Thus it assures a given production ratio with a minimum cost. In the algorithm, FMSs are considered as the closed queueing network with limited queue length. System performance evaluation is performed using the Block-&-Recirculation model developed by Yao and Buzacott. The algorithm is composed with three steps. The steps are namely i) determination of a lower configuration, ii) derivation of an heuristic solution, and iii) obtaining the optimal solution. The computational efforts required in the algorithm usually lies within the capability of personal computers.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2018년도 춘계 종합학술대회 논문집
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• pp.47-48
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• 2018

본 논문에서는 직접 제작한 체험형 VR 시뮬레이션 플랫폼을 바탕으로, 사용성 평가를 통해 본 플랫폼의 타당성을 분석한다. 화재, 지진, 물난리 등의 재난 상황에서 안전하게 대응할 수 있도록 훈련이 가능한 체험형 VR 재난대응 통합훈련 시뮬레이션을 실험참가자에게 체험하게 한 후, 휴리스틱 평가를 실시하여 평가한 데이터를 수집하고 이를 7점 척도 방법으로 결과를 수치화하였다. 본 논문을 통해 상용 전 플랫폼의 가치를 측정해 볼 수 있었으며 이는 제작 후 수정작업에 기여할 수 있는 자료가 될 수 있으리라 사료된다.

• 산업공학
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• 제19권1호
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• pp.86-96
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• 2006

Some customer data of manufacturing industries have a large number of incomplete data set due to the customer's infrequent purchasing behavior and the limitation of customer profile data gathered from sales representatives. So that, most sophisticated data analysis methods may not be applied directly. This paper proposes a heuristic data analysis method to classify customers in household appliances industries. The proposed PD (percent of difference) method can be used for the discriminant analysis of incomplete customer data with simple mathematical calculations. The method is composed of variable distribution estimation step, PD measure and cluster score evaluation steps, variable impact construction step, and segment assignment step. A real example is also presented.

• 한국국방경영분석학회지
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• 제28권2호
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• pp.116-124
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• 2002

In just-in-time production systems, U-shaped production lines rather than traditional straight lines are often adopted since they have some advantages. The advantages of U-lines over straight lines are that the workstations required can be reduced and the necessary number of workers can be easily adjusted when the demand rates are changed. In this paper, we present a new genetic algorithm(GA) to minimize the number of workstations primarily and improve the work relatedness secondarily in the U-line production systems. Also, a new heuristic method is presented according to the work related factors and characteristics of U-line balancing. Some major aspects of the proposed GA are discussed, with emphasis on representation, decoding and evaluation function. Extensive experiments are carried out on well-known test-bed problems in the literature to verify the performance of our algorithm . The computational results show that our algorithm is a promising alternative to existing heuristics.

• 한국정보관리학회:학술대회논문집
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• 한국정보관리학회 2014년도 제21회 학술대회 논문집
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• pp.91-94
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• 2014

본 연구는 일본 엔터테인먼트 웹사이트 이용하는 한국인 이용자의 원활한 이용을 위하여 사용성을 향상 시키는 것에 목적을 두고 진행된 연구이다. 이론 조사를 통하여 사용성에 관하여 조사하였고 이를 통하여 10가지 평가 요소들을 체크리스트를 이용하여 사용성 평가를 하였다. 사용성 평가에는 5개의 웹사이트를 이용하였으며 각각의 웹사이트에서 나타난 문제점을 확인하였고 그에 대한 3가지의 개선 방안을 제시하였다. 첫 번째로 이전 페이지로 돌아가기 기능 제공 및 검색 기능 추가와 개인화 서비스 제공하여 이용자의 통제권을 늘려주는 것, 두 번째로, 명확한 오류 메시지의 제공과 시스템의 오류를 전제로 하는 오류 메시지 구성 및 확인버튼 클릭 후 경고 메시지 제공을 통하여 명확한 오류메시지 전달과 이용자 실수에 대한 방지 방법의 확충, 마지막으로 웹사이트 이용을 위한 도움말을 제공하여 웹사이트의 원활한 이용을 도울 것을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권9호
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• pp.4429-4445
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• 2019

As low-power and low-rate WSNs are being widely used for industrial applications, the scheduling of such applications becomes a critical issue to guarantee meeting the stringent requirements of determinism and tight latencies. This paper studies the link scheduling problem for real-time industrial applications in time-slotted channel hopping (TSCH) networks. We propose a heuristic algorithm for centralized link scheduling referred to as path-collision aware least laxity first (PC-LLF) algorithm, which dynamically prioritizes the packets based on the laxity time to the end-to-end deadlines and the amount of collisions that messages might deal with along their designated paths to the destination device. We propose schedulability analysis of real-time applications scheduled under our prioritization approach over TSCH networks, based on the literature on real-time schedulability analysis of multiprocessors and distributed systems. We show that our methodology provides an improved schedulability condition with respect to the existing approaches. Performance evaluation studies quantify to quantify the performance of our proposed approach under a variety of scenarios.

• 물과 미래
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• 제25권1호
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• pp.83-92
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• 1992

다목적 저수지의 운영을 위해서 여러 가지 대안의 운영율로부터 최상의 안을 선택할 때에는 시스템에 주어진 주요 목적에 부가하여 세부적인 평가 기준들도 고려하여야 한다. 특히 평가 단위가 서로 다른 여러개의 평가기준을 고려할 때에는 경험이나 발견법 만으로는 최상의 안을 선택하기가 어렵게 된다. 다기준 의사 분석기법을 이요하면 여러대안들을 각 평가 기준에 다라 체계적으로 비교하여 대안들의 우선 순위를 결정함으로써 최상의 운영율을 선택할 수 있다. 본 연구에서는 다목적 저수지 시스템의 운영율 평가를 위한 평가 기준을 규명하여 제시하였으며, 다기준 의사분석 기법을 이용하여 충주 다목적 저수지 시스템에 대한 4개의 운영율을 9개의 평가 기준에 따라 평가하였다. 적용 결과 대규모 다목적 저수지 시스템의 운여오가 같이 많은 평가기준을 고려하여 여러 가지 대안의 운영율을 평가할 때에는 이러한 기법이 매우 효율적임을 알 수 있다.