• Journal of Biosystems Engineering
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• 제39권3호
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• pp.158-165
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• 2014

Purpose: The objective of this paper was to compare test standards regarding the performance and safety of agricultural tractors to identify the differences in test conditions, measurement tolerances, and test procedures. Based on the comparison, some recommendations were proposed for possible revisions or improvements to current tractor test standards. Methods: The test standards and codes of major standards development organizations (SDOs), such as the Organization for Economic Cooperation and Development (OECD), the International Organization for Standardization (ISO), the American Society of Agricultural and Biological Engineers (ASABE), EC type approval, and the board of actions of the Nebraska Tractor Test Laboratories (NTTL), were selected and analyzed. Comparison of the test standards: The ISO provides references for fuel and lubricants for tractor tests, and the OECD provides additional measurements for calculating fuel consumption characteristics during the power take-off (PTO) tests. The ISO, EC type approval, and the ASABE provide PTO protective device and the safety requirements. During drawbar power tests, seven transmission ratios are selected for fully automatic transmissions, according to the OECD. In case of hydraulic lift tests, ISO 789-2 and OECD Code 2 advise the use of a static lift force, while SAE J283 advises the use of additional dynamic lift capacity tests for a better representation of in-field operations. The OECD, the ISO, and EC type approval determine the seat index point (SIP), whereas the ASABE determines the seat reference point (SRP) for roll-over protective structure (ROPS) tests. Diversified measurement tolerances were among the braking performance test standards. The European Union (EU) has developed daily limits for vibration exposures with adaptations from ISO 2631-1. Electromagnetic compatibility evaluations are emerging of high-efficiency tractors due to the long-term conformance to electromagnetic emissions and interferences. Comparisons of tractor test standards discussed in this paper are expected to provide useful information for tractor manufacturers and standards development personnel to improve the performance and safety test standards of tractors.

• Structural Engineering and Mechanics
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• 제55권6호
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• pp.1139-1155
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• 2015

In this study, a new retrofitting method for improving the seismic performance of reinforced concrete column was presented, in which prestressed steel strips were utilized as retrofitting stuff to confine the reinforced concrete column transversely. In order to figure out the seismic performance of concrete column specimen retrofitted by such prestressed steel strips methods, a series of quasi-static tests of five retrofitted specimens and two unconfined column specimen which acted as control specimens were conducted. Based on the test results, the seismic performance including the failure modes, hysteresis performance, ductility performance, energy dissipation and stiffness degradation of all these specimens were fully investigated and analyzed. And furthermore the influences of some key parameters such as the axial force ratios, shear span ratios and steel strips spacing on seismic performance of those retrofitted reinforced concrete column specimens were also studied. It was shown that the prestressed steel strips provided large transverse confining effect on reinforced concrete column specimens, which resulted in improving the shearing bearing capacity, ductility performance, deformation capacity and energy dissipation performance of retrofitted specimens effectively. In comparison to the specimen which was retrofitted by the carbon fiber reinforced plastics (CFRP) strips method, the seismic performance of the specimens retrofitted by the prestressed steel strips was a bit better, and with much less cost both in material and labor. From this research results, it can be concluded that this new retrofitting method is really useful and has significant advantages both in saving money and time over some other retrofitting methods.

• Communications for Statistical Applications and Methods
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• 제10권3호
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• pp.765-777
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• 2003

In this paper, we investigate some measures as tests of multivariate normality based on principal components. The idea was proposed by Srivastava and Hui(1987). They generalized Shapiro-Wilk statistic for multi variate cases. We show the null distributions of the statistics do not depend on the unknown parameters and mention the asymptotic null distributions. Also power performance of the tests are assessed in a Monte Carlo study.

• 영재교육연구
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• 제7권1호
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• pp.77-116
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• 1997

The paper-and-pencil multiplce choise test has been widely used to identify gifted and talented student in Korea. Such test have several drawbacks; such~a s not being able to assess creative problem solving abilities and high level thinking abilities which are important characteristics of gifted students. The Korean Educational Development Institute (KEDI) developed a performance assessment which challenged traditional methods of identification. The 5-day summer camp was held to select gifted students for the Korean Minjok Leadership Academy. 211 students were evaluated in the aspects of creative problem solving abilities, high level thinking abilities, task commitments, and cooperativeness with various performance tasks, such as essay tests, conversations, oral examinations, computer simulations, puzzles, experiments, group discussions, debates, research reports, and games. As a result, it was found that there were several limitations of the performance assessment in terms of low reliability, requiring high costs and many professionals, and taking long times and large spaces. Expanding and continuing research should follow in order for a performance assessment to use widely as an identification methods because it assesses 'true' abilities of each individual student. follow in order for a performance assessment to use widely as an identification methods because it assesses 'true' abilities of each individual student.

• 한국간호교육학회지
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• 제21권3호
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• pp.350-360
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• 2015

Purpose: The purpose of this study was to evaluate the effectiveness and retention period of immediate remediation for infant cardiopulmonary resuscitation (CPR) in child care teachers. Methods: This study used a nonequivalent comparison pre- and post-test design to measure knowledge about and confidence in infant CPR and an interrupted time-series design to determine skill performance. The experimental group (n=25) received both immediate remediation and video learning for infant CPR, and the comparison group (n=28) received video learning only. Knowledge and confidence were measured before and after 4 weeks. Their skill performance was tested immediately, and 4 weeks, 8 weeks, 12 weeks, and 24 weeks after intervention. Data analysis consisted of ${\chi}^2$ tests, t-tests, paired t-tests, and a generalized linear mixed model. Results: There were significant increases in knowledge and confidence within the experimental group. Skill performance showed a significant difference according to the group factor (F=10.81, p=.002) and measurement time (F=146.80, p<.001). The experimental group maintained significantly higher skill performance than did the comparison group. Conclusion: These findings support the necessity of immediate remediation education for infant CPR to maintain skill performance. In addition, appropriate renewal time and the improvement of training programs for child care teachers are necessary.

• Communications for Statistical Applications and Methods
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• 제18권1호
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• pp.57-69
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• 2011

질병에 대한 새로운 진단검사 방법이 의학 연구자들에 의해 끊임없이 개발되고 있으며, 기존 진단검사 방법과 새로운 진단검사 방법을 비교하는 연구논문이 계속 출간되어 누적되고 있다. 메타분석법으로 다수 연구논문의 결과를 종합하여 정확성이 높은 진단검사에 대해 객관적인 결론을 내리게 된다. 이와같이 출간된 두 진단검사를 비교하는 각 연구논문은 각각 질병을 가진 개체와 질병을 가지지 않은 개체에 두 검사를 모두 실시하여 한 쌍의 민감도와 특이도를 구하여 비교한다. 이러한 연구논문의 결과를 종합하는 메타분석은 동일 개체에 실시한 두 검사로 인해 한 쌍의 민감도간의 연관성과 한 쌍의 특이도 간의 연관성을 고려한 메타분석법을 본 논문에서 제시한다. 논문예제 자료와 모의시험으로 메타분석 검정통계량의 효율성을 평가한다.

• 한국소음진동공학회논문집
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• 제11권5호
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• pp.108-122
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• 2001

As bridge design is advancing toward the performance-based design. it becomes increasingly important to monitor and re-evaluate the long-term structural performance of bridges. Such information is essential in developing performance criteria for design. In this research. sensor systems for long-term structural performance monitoring have been installed on two highway bridges. Pre1iminary vibration measurement and data analysis have been performed on these instrumented bridges. On one bridge, ambient vibration data have been collected. based on which natural frequencies and mode shapes have been extracted using various methods and compared with those obtained by the preliminary finite element analysis. On the other bridge, braking and bumping vibration tests have been carried out using a water truck In addition to ambient vibration tests. Natural frequencies and mode shapes have been derived and the results by the breaking and bumping vibration tests have been compared. For the development of a three dimensional baseline finite element model, the new methodology using a neural network is proposed. The proposed one have been verified and applied to develop the baseline model of the bridge.

• 수산해양교육연구
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• 제28권1호
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• pp.289-299
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• 2016

The purpose of the study was to develop evaluation methods which would measure student achievement and progress without traditional paper-pencil tests such as mid-term and final examinations. More specifically, the main research focus were to establish general directions of student assessment during free semester, to build evaluation models supporting student's participation and learning, and to report and record various student evaluation results. As research results, we found that student evaluation of free semester should be organized to improve a) experience learning activity, self-regulatory and collaboratory study, b) high-order thinking ability and character-building, and c) teacher-student-parent cooperation. Since traditional paper-pencil tests were restricted in free semester, student achievement should be provided by a way of performance descriptions on transcripts rather than quantitative grade points. Student performance descriptions had to show not only subject knowledge but also students efforts, motivation, and participation. These multiple and educationally meaningful information would be collected by teacher-student-parent communication and collaboration.

• Korean Journal of Radiology
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• 제25권7호
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• pp.656-661
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• 2024

Evaluating the performance of a binary diagnostic test, including artificial intelligence classification algorithms, involves measuring sensitivity, specificity, positive predictive value, and negative predictive value. Particularly when comparing the performance of two diagnostic tests applied on the same set of patients, these metrics are crucial for identifying the more accurate test. However, comparing predictive values presents statistical challenges because their denominators depend on the test outcomes, unlike the comparison of sensitivities and specificities. This paper reviews existing methods for comparing predictive values and proposes using the permutation test. The permutation test is an intuitive, non-parametric method suitable for datasets with small sample sizes. We demonstrate each method using a dataset from MRI and combined modality of mammography and ultrasound in diagnosing breast cancer.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1821-1826
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• 2008

The construction of concrete slab track system is increased recently because the system has advantages which are maintenance free and so on. However, the noise level on slab track is 3 db(A) higher than the one on ballast track since most of noise is reflected on slab track. Currently, concrete slab track systems has been designed for Gyungbu high speed line stage 2 and Honam high speed line. For those tracks, noise absorbing blocks are considered. Therefore, test methods and proper criteria for structural performance and reduction efficiency of noise absorbing blocks are required. In this study, tests were performed according to established test methods and criteria in previous study and the results have done comparative analysis.