• Structural Engineering and Mechanics
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• 제28권3호
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• pp.335-352
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• 2008

Continuous operation of test and measurement is a new operating technique in the petroleum exploitation, which combines perforation with test and measurement effectively. In order to measure the original pressure of stratum layer exactly and prevent testing instrument from being impaired or damaged, a suitable shock absorber is urgently necessary to research. Based on the attempt on the FEM analysis and experiment research, a new shock absorber is designed and discussed in this paper. 3D finite element model is established and simulated accurately by LS-DYNA, the effect and the dynamic character of the shock absorber impact by half sinusoidal pulse force under the main lobe frequency are discussed both on theoretics and experiment. It is shown that the new designed shock absorber system has good capability of shock absorption for the impact load.

• 한국해양공학회지
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• 제32권3호
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• pp.202-207
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• 2018

This paper presents the efficiency of a floating vertical axis wind turbine with variable-pitch. A model was designed to use the lift force and drag force for blades with various pitch angles. The blade's pitch angle is controlled by the stopper. To validate the efficiency of the wind turbine discussed in this paper, a model test was carried out through a single model efficiency experiment and wave tank experiment. The parameters of the single model efficiency experiment were the wind speed, electronic load, and pitch angle. The wave tank experiment was performed using the most efficient pitch angle from the results of the single model efficiency experiment. According to the results of the wave tank experiment, the surge and pitch motion of a structure slightly affect the efficiency of a wind turbine, but the heave motion has a large effect because the heights of the wind turbine and wind generator are almost the same.

• 한국학교ㆍ지역보건교육학회지
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• 제15권2호
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• pp.63-76
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• 2014

Objectives: The purpose of this study was to explore the effects of 'affirmative language' experiment upon freshmen nursing students' negative affect, self-efficacy and stress coping style. Methods: A nonequivalent control quasi-experiment was conducted on the subjects of 55 freshmen nursing students for 26(experimental group) and 29(control group). Data were analyzed using x2-test and t-test for participants' homogeneity test and conducted content analysis of process diary record and personal impressions. Results: As for negative affect, in case of the experimental group, depression(t=-2.384, p=.022) and anxiety(t=-2.243, p=.025) were significantly low with no difference for the control group. As for self-efficacy, both experimental and control groups showed significance and as for stress coping style, the control group used sub-categorized strategies better than the experimental group. There were 4 topics and subsequent 15 topics derived from the content analysis. 'Affirmative language' experiment showed alleviation of depression and anxiety helpful for study participants in self-reporting measurement, and helpful for stress self-management competence. Conclusion: It is necessary to connect the curriculum operation with interest of competence and practice of students stress self-management through the participating experiment experience.

• 한국작물학회지
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• 제45권5호
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• pp.316-321
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• 2000

Blast severity data of 39 rice varieties at 11 sites in Korea from 1997 to 1999 were analyzed using AMMI model and pattern analysis. Genotype x Environment (G$\times$E) interaction sum of squares (SS) accounted for 12 % of the total SS. Eight genotype groups and seven location groups were identified based on blast reaction pattern. The data obtained from over 21 sites with 44 test varieties from 1981 to 1996 were also considered. These were compared with the 1997-1999 data using the G$\times$E analysis results. Majority of the variability in the Korean Rice Blast Nursery (KRBN) were attributable to variations due to genotypes. Variations of G$\times$E interaction were maintained though test sites were reduced from 21 to 11 sites. Broadly compatible biological discriminative varieties identified were Nagdongbyeo and Akibare while broadly incompatible biological discriminative varieties identified were Hangangchalbyeo and Seogwangbyeo. Key sites for future evaluation work could be selected from location groups. Each location group should be represented by the site with the strongest interaction pattern. Blast responses in Cheolwon, Gyehwa, Suwon, Iksan, and Icheon showed different patterns from other locations.

• International Journal of Computer Science & Network Security
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• 제21권12spc호
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• pp.549-555
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• 2021

Machine Learning(ML) splits data into 3 parts, which are usually 60% for training, 20% for validation, and 20% for testing. It just splits quantitatively instead of selecting each set of data by a criterion, which is very important concept for the adequacy of test data. ML measures a model's accuracy by applying a set of validation data, and revises the model until the validation accuracy reaches on a certain level. After the validation process, the complete model is tested with the set of test data, which are not seen by the model yet. If the set of test data covers the model's attributes well, the test accuracy will be close to the validation accuracy of the model. To make sure that ML's set of test data works adequately, we design an experiment and see if the test accuracy of model is always close to its validation adequacy as expected. The experiment builds 100 different SVM models for each of six data sets published in UCI ML repository. From the test accuracy and its validation accuracy of 600 cases, we find some unexpected cases, where the test accuracy is very different from its validation accuracy. Consequently, it is not always true that ML's set of test data is adequate to assure a model's quality.

• 한국과학교육학회지
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• 제40권1호
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• pp.89-96
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• 2020

본 연구에서는 현행 중등 과학과 교사임용시험의 2차 교과교육학 시험의 특징과 개선 방안을 탐구하였다. 임용시험 2차 교과교육학 시험인 교수학습지도안 작성 평가, 수업실연 평가, 교직적성 심층면접 평가, 과학실험시험 등을 중심으로 1차 지필시험과 차별화하면서 2차 실습형 과학교육학 시험의 개선 방안을 탐색하였다. 주요 연구결과로는 교수학습지도안 평가의 경우 1차 지필시험과는 평가초점이 달라서 2차 교수학습지도안 시험을 유지하되, 교수학습지도안 작성의 배점을 줄이고 수업실연의 비중을 높이는 방안 등을 제안하였다. 수업실연 평가의 경우 교사양성과정에서 수업실연을 학점화하여 임용시험에 반영하는 방안, 교육실습이나 실제 수업 상황에서 평가하는 방안, 교과 수업전문성에 초점을 두고 수업실연을 평가할 필요성 등을 제안하였다. 과학실험시험의 경우 모든 시·도교육청에서 과학실험시험을 필수화하고, 실험설계 능력과 실험기반 과학탐구 지도 능력 등을 평가할 필요성 등을 제안하였다. 연구결과를 토대로 수업실연이나 심층면접 등을 시·도교육청에서 자체 출제하는 방안, 수습교사제도 도입의 필요성, 교육전문대학원 도입 방안 등을 제언하였다.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.70-78
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• 2021

Naval surface ships and submarines could be exposed to non-contact underwater explosion(UNDEX) environment. Equipment installed on the ships and submarines could be damaged by shock load generated by UNDEX environment. Therefore, shock survivability of equipment generally evaluated by shock tests. Ground based shock test machine such as Light weight shock test machine(LVSM) is developed to simulate shock load caused by UNDEX environment. In this study, linear dynamic model of LVSM is proposed and evaluated to improve shock test design procedure. Parameters of the model are decided by optimizing time domain response compared to zero payload experiment. Proposed model is verified by comparing simulation results and test results of maximum payload experiment. Finally, shock test design using the model is described for various test equipment weight.

• 대한안전경영과학회지
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• 제12권1호
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• pp.1-9
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• 2010

Recently, in circumstantial situation it is recommended positively to utilize of EIFS(Exterior Insulating and Finishing System) as energy policy for economizing energy. But internal EPS insulators of EIFS are exterior panel of high fire risk, because of constituting of flammable materials to be fragile in fire. In this study, fire risk is assessed by experiment Con Calorimeter test and SBI(Single Burning Item) test. As the result of experiment, Con Calorimeter tests do not reach to capability standard of internal incombustible grade, and are assessed as low grade in SBI incombustible grade. Because EIPS is exterior material in buildings with high fire risk in spite of good efficiency, it is required rapidly to take measures to meet situation through various studies(for instance, adjusting law regulation, etc.) in the future.

• 한국문헌정보학회지
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• 제31권3호
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• pp.165-208
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• 1997

온라인 열람목록의 이용자 인터페이스 특성이 이용행태에 미치는 영향을 파악하고, 이용자에게 보다 친근한 인터페이스를 평가하여 시스템 설계의 방향을 제시하는 데에 본 연구의 목적을 두었다. 이용자 인터페이스에 있어서 뚜렷한 특성상의 차이를 보이는 두 시스템을 대상으로 하여 $2\times2$ 교차계획법으로 이용행태연구를 위한 실험연구를 수행하였다. 65명의 탐색자가 실험에 참여하였다. $2\times2$ 교차계획법에서의 이월효과와 시스템효과, $\chi^2$검증, t 검증 매크네마 검증, 최대우도법을 통한 주변대칭성 검증, 인자분석, 회귀분석, 분산분석 등의 통계기법을 검증해야 할 가설과 데이터의 성격에 따라 적절히 적용하여 분석하였다.

• 한국수정란이식학회지
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• 제29권4호
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• pp.321-325
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• 2014

The present study was performed on farm animals to test the effectiveness of progesterone-releasing intravaginal device (Cue-Mate$^{(R)}$ 1.56 g) and injection of prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) for synchronization estrus in Hanwoo cattle. The cattle were at random stage of the estrus cycle. The cows were artificially inseminated at day 7 after Cue-Mate withdrawal, using commercial semen from Korean native bulls. There was a season effect on the estrus synchronization rate. It was higher in spring (94.3%) followed by winter (93.3%), autumn (90.4%) and summer (67.2%). In summary, The results of this study revealed that season has influences on estrus behavior of cattle with no significant effect on pregnancy rate. In summary, we suggest summer reproductive management to alleviate the effects of heat stress. It should be based on intensive cooling combined with hormonal treatment. Given that different subgroups of cows benefit differently from the treatments, selective hormonal administration should be considered.