• Journal of The Korean Association For Science Education
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• v.24 no.1
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• pp.17-28
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• 2004

The purpose of this study is to determine the patterns of differences between genders in science achievement. Eleventh grade, 140 female and male students were sampled from a school in Seoul. According to the analysis results of pilot study, 20 items were finally selected for the main study. To sharpen our interpretations of the factors and provide some confirmation, we supplemented the statistical analysis with a more detailed cognitive study of the items using think-aloud protocols and interviews with student test takers. The analysis of this study took into account the different item formats, contexts, and presentation styles. The findings are as follows: First, there was no significant gender difference between multiple-choice and open-ended items. Second, male students achieved significantly better in the context of everyday life in multiple-choice items. Third, male students favored items presented as written texts. Fourth, in problem-solving process, female students tend to apply their science concepts, whereas male students tend to apply their everyday experiences. The results of this investigation indicate that gender difference in science achievement depends heavily on item characteristics.

• International Journal of Reliability and Applications
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• v.10 no.1
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• pp.33-42
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• 2009

In most of literatures of age replacement policy, the authors consider the case that a new item starts operating at time zero and is to be replaced by new one at time T. It is, however, often to purchase used items because of the limited budget. In this paper, we consider age replacement policy of a used item whose age is $t_0$. The mathematical formulas of the expected cost rate per unit time are derived for both infinite-horizon case and finite-horizon case. For each case, we show that the optimal replacement age exists and is finite and investigate the effect of the age of the used item.

• Journal of the Korea Safety Management & Science
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• v.2 no.3
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• pp.81-88
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• 2000

In this research, the system is assumed to carry a single item of which the demand types vary. Demand type is defined as a management's classification of the item according to the demand source or to the service purpose. The purpose of this research is to find the optimal inventory control policy when the system carries a single item which consists of multiple demand types. In this research, the optimizing algorithm contains a heuristic, therefore, the optimal is not guaranteed by the algorithm. At least, this research provides the solution to the problems that have not been solved by the existing algorithms.

• Proceedings of the Safety Management and Science Conference
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• 2000.11a
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• pp.127-130
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• 2000

In this research, the system is assumed to carry a single item of which the demand types vary. Demand type is defined as a management's classification of the item according to the demand source or to the service purpose. The purpose of this research is to find the optimal inventory control policy when the system carries a single item which consists of multiple demand types. In this research, the optimizing algorithm contains a heuristic, therefore, the optimal Is not guaranteed by the algorithm. At least, this research provides the solution to the problems that have not been solved by the existing algorithms.

• Journal of the Korean Home Economics Association
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• v.20 no.2
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• pp.135-140
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• 1982

As a step preliminary to the factor-analysis of a child-rearing attitude scale under construction, its preliminary form containing a total of 368 self-answered questions was administerd to 88 married women with one or more children in the grade school age. all graduates of colleges and in possession of a home telephone and a house, twice from one week apart. The test-retest correlation coefficients, calculated for each test item based on the subject's choice among the three response alternatives on two test ocasions, ranged from .80 to .10. The cut-off point of r=.41 or lower led to the elimination of 48 items. As a point of incidental interest, the rate of response concordance. The namber of subjects giving the same categroy response on two occasions was calculated for each item and it was correlated with its test. retest correlation coefficient. The two different indices of item test-retest reliability were found not related to each other. Empirical evidence, as well as rational justifications, was presented to show that the correlation coefficient is the better of the tow indices of item test-retest reliability.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.1539-1542
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• 2003

MPEG-21의 Digital Item은 표준으로 정해진 DID(Digital Item Declaration) 모델을 이용하여 표현된다. 해당 모델은 XML 스키마에 기반하여 정의된 것으로서 뛰어난 표현력과 확장성을 제공할 수 있다. 하지만 정의된 데이터의 저장이나 검색 및 기존 데이터와의 연계에 관한 언급은 표준에서 이루어지지 않고 있다. 본 연구에서는 MPEG-21에서 DID 모델을 이용하여 정의되어 있는 Digital Item을 관계형 데이터베이스에 저장하여 사용할 수 있는 방법에 관하여 논하고자 한다. DID를 이용하여 정의된 내용을 관계형 데이터베이스의 스키마로 매핑 하였으며, SQL 언어를 이용하여 기존 데이터와의 연동 검색을 지원하도록 설계하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.124-130
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• 2015

In many inventory situations, items for sales are generally stocked in a multiple of variations called stockkeeping units, such as size, color, style, and so on. For better management performance on sales items, proper and effective management is necessary for the stockkeeping units. In dealing with many items and those stockkeeping units, individual inventory analysis for each stockkeeping unit needs large amount of time or cost. Also the individual approach in inventory planning increases the demand variation of an item as the result by combining of demand variations of all stockkeeping units, accordingly the inventory turnover ratio and profitability are dropped down. This research suggests an effective method of systematic control of total stockkeeping units by generating from the total item basis, and shows how to reduce the safety stock and the average inventory with attaining a planned customer fill rate of the item and each stockkeeping units.

• Korean Journal of Child Studies
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• v.23 no.4
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• pp.199-213
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• 2002

This preliminary study aimed to develop 3 assessment scales for self-evaluation by day care directors and teachers. The development of major areas of evaluation and items as well as evaluation criteria for each item was based on the analysis of related research and major evaluation instruments. A panel of experts in early childhood education examined the contents. The 3 preliminary scales were administered in 87 day care centers; data were analyzed by item response distribution, item discrimination, and reliability of the scales. Items indicating low item discrimination were deleted and minor revisions were made to improve psychometric characteristics of each scale. The final version of the 3 scales is valid for use as self-evaluation instruments by day care directors and teachers.

• Journal of Families and Better Life
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• v.17 no.3
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• pp.17-32
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• 1999

This study shows how the lifestyle of Housewife as well as usual socio-economic variables affect the expenditure of urban household. The Result of Factor Analysis revealed that the lifestyle of urban housewives were composed by four different traits. 1) self-improvement and rational trait 2) consumption-oriented convenience seeking trait 3) traditional-conservation trait 4) money-oriented variety seeking trait. Based on the Multiple regression analysis the analysis of the relative influence of variables which were associated with the expenditure of each item showed that influential variables for each item were different but economic variables(e, g , income saving, property etc) affected on most of expenditure. Socio-economic variables were more influential than lifestyle variables for every item. But lifestyle variables were influential the same as Socio-economic variables for unnecessary expenditure item more than necessary items particularly consumption-oriented convenience eeking trait and money-oriented variety seeking trait affected.

• Research in Mathematical Education
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• v.11 no.4
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• pp.275-283
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• 2007

In this study, we gave 132 high school students fifteen probabilities and nine statistics problems of the Korean College Scholastic Aptitude Test and then analyzed their answer using the classical test theory and the item response theory. Using the classical test theory (the Testian 1.0) we get the item reliability ($0.730 \sim 0.765$), and using the item response theory (the Bayesian 1.0) we get the item difficulty ( $-2.32\sim0.83$ ) and discrimination ( $0.55\sim 2.71$). From results, we find out what and why students could not understand well.