• Proceedings of the KSME Conference
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• 2000.04a
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• pp.725-730
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• 2000

Genetic algorithms based on the theory of natural selection, have been applied to many different fields, and have proven to be relatively robust means to search for global optimum and handle discontinuous or even discrete data. Genetic algorithms are widely used for unconstrained optimization problems. However, their application to constrained optimization problems remains unsettled. The most prevalent technique for coping with infeasible solutions is to penalize a population member for constraint violation. But, the weighting of a penalty for a particular problem constraint is usually determined in the heuristic way. Therefore this paper proposes, the effective technique for handling constraints, the ranking penalty method and hybrid genetic algorithms. And this paper proposes dynamic mutation tate to maintain the diversity in population. The effectiveness of the proposed algorithm is tested on several test problems and results are discussed.

• Proceedings of the KIEE Conference
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• summer
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• pp.171-173
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• 2004

This paper presents the selection of optimal placement for STATCOM (Static synchronous Compensator) which is one of the FACTS (Flexible Alternating Current Transmission System) devices, considering line contingency. Line contingency ranking is gotten by using sensitivity of load margin. According to line contingency ranking line contingency was considered. And IOP (Index for selecting optimal Placement of STATCOM) is calculated by the variation of each bus's reactive mum for several line contingencies. The bus where has the biggest value of lOP is the most optimal placement to install STATCOM for voltage stability. IPLAN is used to program this part which get IOP. This study is carried out on the modified IEEE14 Bus Test System to confirm the efficiency of the method.

• The Mathematical Education
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• v.38 no.2
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• pp.129-144
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• 1999

The purpose of our work is to developing the program of math. camp to improve underachiever's mathematical disposition. To do this, the following research were taken; (1)Analysis of current status of programs for underachievers (2)Analysis of inclination to mathematics(We collected the data from 2 classes of middle schools) (3)Prepare and apply the program of math. camp for the students including underachievers, and then analysis the effect of the math. camp The results of this study is as follows; (1)Only 40% of investigated schools have their own programs for underachievers. But almost all general high schools do not have such programs because students do not want. More than half of the investigated teachers suggested that the most important thing for underachievers is the induction of motivation for mathematics. (2)Many students dislike mathematics from 5∼6 grade of elementary school, and more than 50% of students think that 'measure' and 'equations' items are difficult. (3) After attending the math. camp based on the games and activities in small groups, the students in the middle-ranking group showed more positive reactions against the items of mathematical disposition and attitude tests. The students in the row-ranking group were improved in the 'self-confidence' and 'will' items of mathematical disposition test and in the 'superiority' and 'interest' items of mathematical attitude test.

• Culinary science and hospitality research
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• v.13 no.3
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• pp.252-262
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• 2007

The object of this research is to assess the preference for commercial cream soup by gender and age group in order to develop reliable proposals for a better product. A total of 488 questionnaires were handed out to residents in the Seoul area. The data were analysed using chi-square test, t-test and one-way ANOVA. The results are summarized as follows: (1) 80.3% liked soup because of its flavor, taste, and ingredients, (2) respondents in their $20{\sim}30's$ exhibited higher preference than respondents in their $40{\sim}50's$, (3) the main ingredient is the most important consideration for purchase, (4) mush-room cream soup and broccoli cream soup earned the highest ranking in terms of soup brand recognition, (5) mushroom cream soup and broccoli cream soup earned the highest ranking in terms of soup preference.

• Journal of applied mathematics & informatics
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• v.3 no.2
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• pp.235-244
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• 1996

Ranked-set sampling is useful when measurements are destructive or costly to obtain but ranking of the observations is rel-atively easy. The Wilcoxon signed rank test statistic based on the ranked-set sample is considered. We compared the asymptotic relative efficiencies of the RSS Wilcoxon signed rank test statistics with respect to the SRS Wilcoxon signed rank test statistic and the RSS sign test statistic. Throughout the ARE's the proposed test statistic is superior to the SRS Wilcoxxon signed rank test statistic and the RSS sign test statistic.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.23-34
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• 2009

This paper is described as an experimental analysis for the probabilistic directional design hour volume estimation. The main objective of this paper is to derive acceptable design rankings, PK factors, and PD factors. In order to determine an appropriate distribution for acceptable design rankings, 12 probability distribution functions were employed. The parameters were estimated based on the method of maximum likelihood. The goodness of fit test was performed with a Kolmogorov-Smirnov test. The Beta General distribution among the probability distributions was selected as an appropriate model for 2 lane roadways. On the other hand, the Weibull distribution is superior for 4 lanes. The method of the inverse cumulative distribution function came up with an acceptable design ranking of design for LOS D. An acceptable design ranking of 2 lanes is 190, while an acceptable design ranking for 4 lanes is 164. The PK factor and PD factor of 2 lanes was elicited for 0.119 (0.100-0.139) and 0.568 (0.545-0.590), respectively. On the other hand, the PK factor and PD factor for 4 lanes was elicited as 0.106 (0.097-0.114) and 0.571 (0.544-0.598), respectively.

• The Korean Journal of Applied Statistics
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• v.31 no.3
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• pp.409-416
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• 2018

Significant research has been conducted in the financial sector on the behavior of investors in the stock market. In this paper, we directly measure the degree of interest using the ranking of the frequency mentioned in the stock message board operated by Daum Communications Corp. and test the fact that the higher ranking of the frequency results in the higher stock returns in order to investigate the attention effect on the stock returns in the Korean stock market. We also propose and apply the likelihood ratio test procedure for order restricted hypotheses in order to test the attention effect. The test results shows that the higher rank in the frequency mentioned in the message board is related to stock returns (p-value < $10^{-6}$). Therefore, we conclude that an investors' attention effects exist in the Korean stock market.

• Journal of the Korean earth science society
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• v.24 no.7
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• pp.614-624
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• 2003

The purpose of this study was to examine the effectiveness of utilizing a concept map as an instructional strategy to promote student achievement through semantical learning in elementary school on volcanoes. To analyze student achievement in understanding the concept of volcano, quantitative and qualitative analyses were performed through a written test for two different groups that were composed of 80 sixth-grade students: a control group that attended class using the conventional strategy and an experimental group that attended class using concept maps. The results of this study were as follows: First, the use of concept maps in class is effective in learning because of the higher understanding of the group that was using concept maps in the achievement assessment. Second, in their post-instructional understandings, no significant differences are shown between middle- and low-ranking students statistically, but a significant difference is shown between high- and low-ranking students or between high- and middle-ranking students. This indicates that the use of concepts maps in a class is more effective for the middle- and low-ranking students than for the high-ranking students. Third, in the repetitions of classes, the students learning with an aid of concept maps became accustomed to structuring the concepts of their learning subject in categories of relationships, hierarchies, cross-links, and examples easily.

• Genomics & Informatics
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• v.2 no.4
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• pp.180-183
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• 2004

Comparative Statistic Module(CSM) provides more reliable list of significant genes to genomics researchers by offering the commonly selected genes and a method of choice by calculating the rank of each statistical test based on the average ranking of common genes across the five statistical methods, i.e. t-test, Kruskal-Wallis (Wilcoxon signed rank) test, SAM, two sample multiple test, and Empirical Bayesian test. This statistical analysis module is implemented in Perl, and R languages.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1412-1420
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• 2018

An experiment was performed using the large-scale test facility (LSTF), which simulated a 1% vessel upper head small-break loss-of-coolant accident with an accident management (AM) measure under an assumption of total-failure of high-pressure injection (HPI) system in a pressurized water reactor (PWR). In the LSTF test, liquid level in the upper head affected break flow rate. Coolant was manually injected from the HPI system into cold legs as the AM measure when the maximum core exit temperature reached 623 K. The cladding surface temperature largely increased due to late and slow response of the core exit thermocouples. The AM measure was confirmed to be effective for the core cooling. The RELAP5/MOD3.3 code indicated insufficient prediction of primary coolant distribution. The author conducted uncertainty analysis for the LSTF test employing created phenomena identification and ranking table for each component. The author clarified that peak cladding temperature was largely dependent on the combination of multiple uncertain parameters within the defined uncertain ranges.