• International Journal of Concrete Structures and Materials
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• 제2권1호
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• pp.57-62
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• 2008

When the yield line theory is used to estimate the ultimate strength of a concrete barrier, it is of primary importance that the correct assumption is made for the failure mode of the barrier. In this study, a static test was performed on two full-scale concrete barrier specimens of Korean standard shape that simulate the actual behavior of a longitudinally continuous barrier. This was conducted in order to verify the failure mode presented in the AASHTO LRFD specification. The resulting shape of the yield lines differed from that presented in AASHTO when subjected to an equivalent crash load. Furthermore, the ultimate strengths of the specimens were lower than the theoretical prediction. The main causes of these differences can be attributed to the characteristics of the barrier shape and to a number of limitations associated with the classical yield line theory. Therefore, a revised failure mode with corresponding prediction equations of the strength were proposed based on the yield lines observed in the test. As a result, a strength that was more comparable to that of the test could be obtained. The proposed procedure can be used to establish more realistic test levels for barriers that have a similar shape.

• 한국전문물리치료학회지
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• 제26권3호
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• pp.106-114
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• 2019

Background: It is difficult to assess whether community-dwelling frail older adults may remain pre-frail status or improve into a robust state without being directly checked by health care professionals. The health information perceived by older adults is considered to be one of best sources of potential concerns in older adult population. An online measurement system combined with item response theory (IRT) and computer adaptive testing (CAT) methods is likely to become a realistic approach to remotely monitor physical activity status of frail older adults. Objects: This article suggests an approach to provide a precise and efficient means of measuring physical activity levels of community-dwelling frail older adults. Methods: Article reviews were reviewed and summarized. Results: In comparison to the classical test theory (CTT), the IRT method is empirically aimed to focus on the psychometric properties of individual test items in lieu of the test as a whole. These properties allow creating a large item pool that can capture the broad range of physical activity levels. The CAT method administers test items by an algorithm that select items matched to the physical activity levels of the older adults. Conclusion: An online measurement system combined with these two methods would allow adequate physical activity measurement that may be useful to remotely monitor the activity level of community-dwelling frail older adults.

• 한국과학교육학회지
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• 제24권3호
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• pp.519-531
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• 2004

최근 제7차 교육과정이 실시되면서 준거 지향적인 수행평가에 대한 요구가 커지고 있으며, 이러한 상황에서 평가의 절대적인 기준을 마련할 필요성 또한 절실해지고 있다. 본 연구는 제7차 교육과정에 근거하여 고등학교 과학 중 '생식' 단원과 '생물 농축' 단원에 대해서 필수 학습 요소, 성취 기준, 평가 기준 및 평가 문항을 개발하고, 이를 바탕으로 개발한 평가 문항을 실제 현장에 적용하여 그 타당성을 검증하는 것을 목적으로 한다. 본 연구에서는 제7차 교육과정과 고등학교 과학의 7종 교과서를 바탕으로 하여, '생식' 과 '생물 농축' 단원의 필수 학습 요소를 추출하고, 준거 지향 평가의 기초가 되는 객관적이고 타당한 성취 기준 및 평가 기준을 마련하였다. 추출된 필수 학습 요소는 '생식' 단원에서 12개, '생물 농축' 단원에서 4개이었으며, 개발된 성취 기준은 '생식' 단원에서 총 26개, '생물 농축' 단원에서 총 9개로 각각은 지식(K), 탐구(P), 태도(A)의 세 개 영역으로 구분하여 개발하였다. 이상과 같이 개발된 성취 기준을 바탕으로 평가 기준을 개발하였다. 개발된 평가 기준의 수는 '생식' 단원에서 총 25개, '생물 농축' 단원에서 9개였다. 성취 기준과 평가 기준에 따라 '생식' 단원과 '생물 농축' 단원에서 개발된 평가 문항의 수는 서술형 문항 17개, 논술형 문항이 13개, 포트폴리오가 2개로 총 22문항이었다. 각 평가 문항은 구체적인 채점 기준을 제시하였으므로, 교육과정에 근거한 객관적인 평가에 사용될 수 있다. 개발된 평가 문항 중, 서술형 문항 8개를 경기도 소재 고등학교 1학년 학생 240명을 대상으로 적용 분석하였다. 서술형 문항에 대한 학생들의 응답을 두 가지 검사 이론을 적용하여 분석하였는데, 평가 문항의 기본적인 양호도 검증을 실시한 결과, 본 연구에서 개발된 서술형 문항들은 난이도와 변별도 면에서 전반적으로 적절한 지수를 보여 수행 평가로 사용하기에 적절한 문항들이었다. 개발한 서술형 수행 평가 문항들은 미리 개발된 성취 기준과 평가 기준을 바탕으로 하였으므로 교수 학습의 목표와 내용에도 적합하였다. 고전 검사 이론과 다분 문항 반응 이론에 의해 분석된 문항의 변별도에는 언어적인 해석의 차이가 없었으나, 문항 난이도의 경우는 고전 검사 이론을 사용하였을 때 집단의 특성이 많이 나타나 다분 문항 반응 이론을 사용한 결과와 비교하여 해석의 차이가 다양하게 나타났다.

• 한국경영과학회지
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• 제13권2호
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• pp.215-215
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• 1988

This paper presents a fuzzy set theory based formulation and heuristic which will allow plant layout problems to be solved for more than two input goals with different weights. The heuristic combines a construction and improvement procedure to generate a good layout from the formulation. To test the effectiveness of the heuristic, a set of examples previously used by various authors is solved and the results are compared to those from other known heuristics. The comparison indicates that the proposed method performs well for each of seventeen classical test problems.

• 경영과학
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• 제13권2호
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• pp.215-232
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• 1996

This paper presents a fuzzy set theory based formulation and heuristic which will allow plant layout problems to be solved for more than two input goals with different weights. The heuristic combines a construction and improvement procedure to generate a good layout from the formulation. To test the effectiveness of the heuristic, a set of examples previously used by various authors is solved and the results are compared to those from other known heuristics. The comparison indicates that the proposed method performs well for each of seventeen classical test problems.

• 대한수학회지
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• 제46권5호
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• pp.1041-1069
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• 2009

We study the periodic homogenization of the non-stationary Stokes equations. The fundamental homogenization theorem and corrector theorem are proved under a very general assumption on the viscosity coefficients and data. The proofs are based on a weak formulation suitable for an application of classical Tartar's method of oscillating test functions. Such a weak formulation is derived by adapting an argument in Teman's book [Navier-Stokes Equations: Theory and Numerical Analysis, North-Holland, Amsterdam, 1984].

• Journal of Korea Trade
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• 제25권4호
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• pp.88-107
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• 2021

Purpose - Using a model that highlights Ricardian comparative advantage and Cournot competition, I derive theoretical predictions on how bilateral measures of trade intensity, specialization, and intra-industry are interrelated, and how Ricardian productivity differences affect these measures. We test the predictions using trade and production data, and confirm them. Design/methodology - A simple two-country general equilibrium model is constructed to derive theory-based bilateral indexes. We then test the relationships among them using panel data for 35 countries and 14 industries between 1996 and 2008. Findings - Bilateral trade intensity is increasing in specialization, as in the classical trade theory, and in intra-industry trade, as in the new trade theory. However, productivity differences positively affect specialization, and negatively affect intra-industry trade. These effects cancel each other; thus productivity differences have little impact on trade intensity. Originality/value - This paper provides a comprehensive conceptual framework for understanding the relationship among trade intensity, specialization, intra-industry trade, and productivity differences. We derive theory-consistent measures of specialization, intra-industry trade, and productivity differences. Moreover, we reevaluate the empirical relevance of these variables for the study of gravity equations. This paper is also an effort to capture oligopolistic competition in a general equilibrium framework, interests in which recently resurged.

• 한국지반환경공학회 논문집
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• 제5권3호
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• pp.17-30
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• 2004

본 연구에서는 현장타설말뚝의 지지력에 관한 기존 및 IGM 이론의 적용성을 비교 평가하고, 변위를 고려한 지지력의 결정을 위해 IGM 상단부에서의 기준침하량 결정식을 제안하였다. 제안식은 말뚝의 두부침하량, IGM 상부 토층의 하중전이특성 및 말뚝의 탄성압축 이론에 기초하였다. 특히, 기존 및 IGM 이론의 적용성과 제안식의 적용성을 검증하기 위해 국내외 재하시험 결과를 이용한 분석이 실시되었다. 재하시험 결과를 이용하여 분석한 결과 제안식이 활용된 IGM 이론에 의해 향후 말뚝 설계시 변위를 고려한 지지력의 해석이 가능할 것으로 판단되었다. 특히, 제안식에 도입된 침하보정계수 $k_m$은 지반상태나 하중전이 특성을 반영하는 계수로서 하중 및 변형 증가에 따라 변화하는 특징을 보였다.

• 공학교육연구
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• 제26권6호
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• pp.40-50
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• 2023

This study is to examine the validity of assessing basic-level proficiency in physics among incoming engineering freshmen through item analysis and standard setting. For empirical analysis, we examined the physics subject taken by the freshman class of 2021 at K University, considering its significance for engineering students. In this study, we initially performed item analysis utilizing both classical test theory and item response theory. Subsequently, leveraging the item and test information, we employed a modified Angoff method and the Bookmark method for standard setting. Consequently, the difficulty level initially set during item development was found to be higher than the actual performance level exhibited by the students. This study highlights a discernible disparity between the expected university standard and the real proficiency level of incoming freshmen in terms of basic academic ability in physics. Based on these research findings, a comprehensive discussion on the fundamental academic competence of engineering students was conducted, underscoring the necessity for formulating a tailored learning approach leveraging the outcomes from the basic ability test.

• 대한간호학회지
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• 제45권1호
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• pp.107-117
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• 2015

Purpose: The purpose of this study was to evaluate the psychometric properties of the Korean version of the Alzheimer's Disease Knowledge Scale (ADKS-K) to determine its applicability to Korean adults. Methods: Cross-cultural validity was performed according to Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN). The Kuder-Richardson Formula 20 for internal consistency and Intraclass Correlation Coefficient (ICC) for test-retest reliability were conducted. Content validity, criterion related validity and construct validity were evaluated. The Classical Test Theory (CTT) model and the Item Response Theory (IRT) model were applied in performing the item analysis. Results: The KR 20 was .71, and the ICC was .90, indicating that the ADKS-K has internal consistency and stability reliability. Thirty items of the ADKS-K had significant Content Validity Ratio (CVR) values, i.e., mean of 0.82 and range of 0.60~1.00. Mean item difficulty and discrimination indices calculated by TestAn program were 0.63 and 0.23, respectively. Mean item difficulty and discrimination indices calculated by BayesiAn program were -0.60 and 0.77, respectively. These tests indicate that ADKS-K has an acceptable level of difficulty and discriminating efficiency. Conclusion: Results suggest that ADKS-K has the potential to be a proper instrument for assessing AD knowledge in Korean adults.