• Structural Engineering and Mechanics
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• 제55권5호
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• pp.979-999
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• 2015

This paper proposes a novel reliability analysis method which computes reliability index, most probable point and probability of failure of uncertain systems more efficiently and accurately with compared to Monte Carlo, first-order reliability and response surface methods. It consists of Initial and Simulation steps. In Initial step, a number of space-filling designs are selected throughout the variables space, and then in Simulation step, performances of most of samples are estimated via interpolation using the space-filling designs, and only for a small number of the samples actual performance function is used for evaluation. In better words, doing so, we use a simple interpolation function called "reduced" function instead of the actual expensive-to-evaluate performance function of the system to evaluate most of samples. By using such a reduced function, total number of evaluations of actual performance is significantly reduced; hence, the method can be called Reduced Function Evaluations method. Reliabilities of six examples including series and parallel systems with multiple failure modes with truncated and/or non-truncated random variables are analyzed to demonstrate efficiency, accuracy and robustness of proposed method. In addition, a reliability-based design optimization algorithm is proposed and an example is solved to show its good performance.

• 수산경영론집
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• 제49권4호
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• pp.37-52
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• 2018

Busan is a representative of ocean cities in South Korea, which attracts many Chinese tourists. As a number of Chinese tourists increase, Chinese tourists' evaluations of sightseeing resources in Busan appear extremely important. However, there are few researches on Chinese tourists' evaluations of sightseeing in Busan. The purpose of this paper is to analyze Chinese tourists' evaluations of Busan tourism. Chinese tourists who travel to Busan are chosen as research objects and several aspects including marine, fisheries and general tourism are investigated to evaluate the tourists' overall satisfaction of the tourism in Busan. IPA analysis, factor analysis multiple regression analysis are used for the research. The results are as follows. Chinese tourists' evaluations of the importance and performance level of variables on Busan tourism were significantly different (total 19 of 25 variables) and the performance was lower than importance. This means the outputs of the various Busan tourism elements do not live up to their expectations. The findings show that Chinese visitors have high satisfaction on infrastructures of fisheries tourism (e.g. cleanness of aquatic product tourism facilities and sanitary state on fishery products), but low satisfaction in terms of the contents (e.g. unique cooking method experience of seafood and traditional seafood cooking consumption). The factors of fisheries tourism (e.g. product services of fisheries tourism and the attractiveness of seafood in Busan) never affect their satisfaction and intention to revisit and recommend the city.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.44-49
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• 2001

This paper is concerned with development of a multi-attribute structured decision model. In this study, we used AHP(analytic hierarchy process) and fuzzy set ranking methodology to overcome the multi-attributes structured decision problems ; such as multi-objective, multi-criterion, and multi-attributes. We proposed a 2-step approach : 1) individual evaluation and 2) integration of individual evaluations. In the first step, we define the performance factors and construct ana]isis structure, and in the second step performance evaluation by individual evaluators, and in second step, the results of individual evaluations are integrate. Also we developed a systematic and practical computer program to solve the problems according to the proposed methods. The proposed approach was known to be effective through a set of sample problems.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.851-854
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• 1998

In recent years, a cost-effective voltage-source type single-ended resonant-load inverter using MOS gate power switching devices and its related resonant inverter topologies have been commonly used for induction-heated cooking appliances because of relatively-lowered switching losses, simple circuit topology, low cost, compactness and low harmonic current in utility AC side. This paper present some comparative performance evaluations of IGBTs as sample devices in each generation and MOS controlled Thyristor(MCT) incorporated into the voltage-source type single-ended load resonant inverter for induction-heating rice cookers used for consumer power electronic applications, in which the output power can be regulated on the basis of Frequency Modulation Scheme.

• 가정과삶의질연구
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• 제19권5호
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• pp.15-32
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• 2001

The purpose of this study were to develop family welfare service program on interrelationship improvements of children. For this purpose, programs related to children that is performed by social welfare agency and that is based on group psychotherapy were included. The results were as follows. First. programs related to children that is performed by social welfare agency are insufficient to evaluations of plans, performance and outputs. In particular, speciality of social worker in perform on programs in related to children is absent. Second, programs of interrelationship improvements of children based on group pychotherapy were specialized in evaluations of plans, performance and output. Through out this analysis, the program of interrelationship improvements of children is developed. This program is based on group psychotherapy, include art therapy, sociodrama.

• ETRI Journal
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• 제43권3호
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• pp.549-560
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• 2021

Cyberattacks are often difficult to identify with traditional signature-based detection, because attackers continually find ways to bypass the detection methods. Therefore, researchers have introduced artificial intelligence (AI) technology for cybersecurity analysis to detect malicious PowerShell scripts. In this paper, we propose a feature optimization technique for AI-based approaches to enhance the accuracy of malicious PowerShell script detection. We statically analyze the PowerShell script and preprocess it with a method based on the tokens and abstract syntax tree (AST) for feature selection. Here, tokens and AST represent the vocabulary and structure of the PowerShell script, respectively. Performance evaluations with optimized features yield detection rates of 98% in both machine learning (ML) and deep learning (DL) experiments. Among them, the ML model with the 3-gram of selected five tokens and the DL model with experiments based on the AST 3-gram deliver the best performance.

• 비교교육연구
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• 제28권2호
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• pp.1-21
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• 2018

본 연구는 독일 영어중등교원이 수업시간 학생들의 수행에 대한 평가를 어떻게 인식하고 있는가에 대해서 탐구하는 것을 그 목적으로 한다. 이를 수행하기 위하여 독일 작센주 라이프치히 대학으로부터 연구 참여가 가능한 7학년 중등 영어교사의 리스트를 받고 그 중 인터뷰 일정이 안 맞거나 인터뷰 결과가 출판되는 것에 동의하지 않는 교사를 제외하고 참여 가능한 4명의 영어교사를 최종 선정하였다. 반구조화된 질문지를 바탕으로 심층면접을 실시한 결과 다음과 같은 논의를 도출하였다. 첫째, 독일 영어교사들이 수업시간 중 수행평가에 대해서 수행의 정도를 교사를 중심적으로 생각하기보다 학생들이 스스로 자신의 수행에 정도에 대해 느끼는 것을 중요하게 생각한다. 둘째, 독일 영어교사들은 수행 평가시 절대적인 평가의 기준을 제공하고 그에 맞추어 학습자를 평가하기보다는 수행을 개별적인 행위로 인식하여 개별적 성과를 기준으로 학생들을 평가하고 있었다. 이를 위해서 동료평가를 통해 평가결과에 대한 객관성을 확보하고 있었다. 그들은 학생을 평가에 중요한 대상이자 또 다른 평가자로서 믿고 있었으며 학생들의 개별적인 성장을 위한 조력자로 인식하고 있었다. 셋째, 교수자의 강력한 평가에 대한 권한을 바탕으로 1년에 3번 본인이 원하는 범위와 일자에 총괄평가를 할 수 있어 자신의 평가에 대한 책임과 학습자의 학습을 효과적으로 관리하는 평가시스템을 운영하고 있었다. 넷째, 독일 교사들은 평가를 통해 학습자의 동기를 부여하고 학습의 수월성보다는 학습결과가 고르게 이루어지도록 하는 것이 수업시간 내 학습자의 참여를 유발시키는 기재라고 보고하였다. 본 연구가 지닌 질적 연구방법의 한계로 인해 연구결과를 독일 전역으로 일반화하기는 어렵겠지만, 쉽게 접근하기 어려운 독일의 교실 속 수행평가에 대한 교사의 인식을 탐색함으로써 우리나라 중등교육의 수행평가에 주는 시사점을 도출할 수 있었다. 후속연구에서는 교사의 인식뿐만 아니라 학교 현장에 대한 관찰이나 학생의 시각에서 평가를 바라보는 인식 등을 통해 독일의 학교현장을 다양한 시각에서 이해하는 것이 필요할 것으로 보인다.

• 대한기계학회논문집A
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• 제30권8호
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• pp.985-992
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• 2006

Many methods for reliability analysis have been studied and one of them, a moment method, has the advantage that it doesn't require sensitivities of performance functions. The moment method for reliability analysis requires the first four moments of a performance function and then Pearson system is used for the probability of failure where the accuracy of the probability of failure greatly depends on that of the first four moments. But it is generally impossible to assess them analytically for multidimensional functions, and numerical integration is mainly used to estimate the moment. However, numerical integration requires many function evaluations and in case of involving finite element analyses, the calculation of the first fo 따 moments is very time-consuming. To solve the problem, this research proposes a new method of approximating the first four moments based on kriging metamodel. The proposed method substitutes the kriging metamodel for the performance function and can also evaluate the accuracy of the calculated moments adjusting the approximation range. Numerical examples show the proposed method can approximate the moments accurately with the less function evaluations and evaluate the accuracy of the calculated moments.

• 한국임상수의학회지
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• 제32권4호
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• pp.319-323
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• 2015

The performance of diagnostic test accuracy is usually summarized by a variety of statistics such as sensitivity, specificity, predictive value, likelihood ratio, and kappa. These indices are most commonly presented when evaluations of competing diagnostic tests are reported, and it is of utmost importance to compare the accuracies of diagnostic tests to decide on the best available test for certain medical disorder. However, it is important to emphasize that specific point values of these indices are merely estimates. If parameter estimates are reported without a measure of uncertainty (precision), knowledgeable readers cannot know the range within which the true values of the indices are likely to lie. Therefore, when evaluations of diagnostic accuracy are reported the precision of estimates should be stated in parallel. To reflect the precision of any estimate of a diagnostic performance characteristic or of the difference between performance characteristics, the computation of confidential interval (CI), an indicator of precision, is widely used in medical literatures in that CIs are more informative to interpret test results than the simple point estimates. The majority of peer-reviewed journals usually require CIs to be specified for descriptive estimates, whereas domestic veterinary journals seem less vigilant on this issues. This paper describes how to calculate the indices and associated CIs using practical examples when assessing diagnostic test performance.

• 교통기술과정책
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• 제9권2호
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• pp.77-85
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• 2012