• East Asian mathematical journal
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• 제30권4호
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• pp.451-474
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• 2014

The purpose of this study is to analyze error patterns third-year middle school students make on quadratic function graph problems and to examine about the possible correct them by providing supplementary tutoring. To exam the error patterns that occur during problem solving processes, to 82 students, We provided 25 quadratic function graph problems in the preliminary-test. The 5 types of errors was conceptual errors, false intuition errors, incorrect use of conditions in problems, technical errors, and errors from slips or carelessness. Statistical analysis of the preliminary-test and post-test shows that achievement level was higher in the post-test, after supplementary tutoring, and the t-test proves this to be meaningful data. According to the per subject analyses, the achievement level in the interest of symmetry, parallel translation, and general graph, respectively, were all higher in the post-test than the preliminary-test and this is meaningful data as well. However, no meaningful relation could be found between the preliminary-test and the post-test on other subjects such as graph remodeling and relations positions of the parabola. For the correction of errors, try the appropriate feedback and various teaching and learning methods.

• 대한가정학회지
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• 제20권2호
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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.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.885-891
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• 2011

본 논문은 액체산소와 케로신을 추진제로 하는 액체로켓엔진의 성능평가를 위한 엔진 지상 연소시험설비 예비설계 결과를 기술하였다. 엔진 지상 연소시험설비의 설계 요구조건에 기반한 설계 규격 및 설비 구성을 제시하였다. 엔진 지상 연소시험설비 예비설계 결과는 향후 한국형발사체 75톤급 엔진 지상 연소시험설비의 상세설계 및 구축을 위한 기본 자료로 활용될 예정이다.

• Journal of Astronomy and Space Sciences
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• 제27권2호
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• pp.135-144
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• 2010

In this paper, we present the result of preliminary design of tracking mount for ARGO-M which is a movable satellite laser ranging (SLR) system developed by Korea Astronomy and Space Science Institute (KASI). The tracking mount consists of a couple of core parts such as driving motors, encoders and bearings, and the requirements of each parts are determined on the basis of the technical consideration. 2D and 3D models for tracking mount were preliminarily designed using the selected core parts. In order to evaluate the validity of the preliminarily design, the simulator to test the elevation axis was designed and manufactured. The test to check the tracking performance and system accuracy of the simulator was performed, and it was confirmed that the preliminary design meets the operating specifications. Additionally, it was found that the repetitive errors and hysteresis errors need to be improved by the additional control algorithm.

• 대한기계학회논문집
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• 제19권7호
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• pp.1780-1786
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• 1995

The main goal of the present study is to establish the techniques and methodolgies of turbine performance test through evaluating the objective turbine test piece, and checking the reliability of the self-developed test facility by performing a series of turbine tests under ambient temperature condition. A high speed coupling, a lubrication system and a test bed of the test facility were modified through a series of preliminary test in order to reduce the vibration and oil leakage. The flowrate control of the test facility and data acquisition were accomplished by using a software called "Labview" The measurement of shaft horse power and control of rotational speed according to the conditions of turbine rotation were performed by a separate system. The preliminary evaluation of the measured data suggests that the developed test facility and the test technique can be used reliably for the performance test of turbines with the minor improvement.provement.

• International Journal of Reliability and Applications
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• 제14권2호
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• pp.79-96
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• 2013

Exponential distribution plays a key role in engineering reliability and its applications. The exponential failure model has been studied for years. This article introduces two new preliminary test estimators for the reliability function (R(t)) in complete and censored samples from the exponential model with the use of a prior estimation (${\theta}_0$) of the mean (${\theta}$). The proposed preliminary test estimators are studied and compared numerically with the existing estimators. Computer-intensive calculations for bias and relative efficiency show that for, different values of levels of significance and for varying constants involved in the proposed estimators, the proposed estimators are far better than classical and existing estimators.

• 자동차안전학회지
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• 제5권2호
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• pp.5-10
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• 2013

The pole side crash caused fatal injury by comparison with other crash impact mode such as frontal and rear crash. EuroNCAP proposed the pole side crash test using WorldSID(World Side Impact Dummy). The objective of this study is to develop the pole side impact sled test using dummy rib deflection between crash and sled test. In the pursuit of this purpose, we fabricated new pole side sled buck and test preliminary pole sled using ES-2re. Through this, we found the sled acceleration pulse scale. Hardness and thickness of the EPP affects the rib deflection. We conducted the pole sled test using WorldSID based on the preliminary results. As a result, rib deflection was shown to correlate well between crash test and pole side sled test.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.155-158
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• 2007

액체로켓엔진 개발 시험의 중간 단계로서 연소기를 제외한 터보펌프 등의 엔진 주요 구성품을 이용한 터보펌프+가스발생기 연계시험이 수행 중에 있다. 터보펌프+가스발생기 연계시험의 시험기 및 시험설비 구성을 기술하였다. 연계시험 수행을 위한 시험설비 시스템 검증 시험 결과를 제시하였다. 시험설비에 대한 예비시험 결과를 토대로 시험설비 추진제 공급시스템의 검증이 수행되었다.

• 지역사회간호학회지
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• 제19권2호
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• pp.247-259
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• 2008

Purpose: This study was conducted to develop a teacher-efficacy scale which is adequate for heath education teachers. Method: A preliminary questionnaire was made based on the hypothetical factors. A total of 364 health education teachers answered to the preliminary test, and the potential factors of teacher-efficacy were checked out by exploratory factor analysis (EFA). In the main test 378 health education teachers answered, the factor structure was drawn by EFA, and confirmatory factor analysis (CFA) was conducted to test and the fitness of the factor model. Results: Through the preliminary test, 5 potential factors were found, which were instruction, health-service, administrative task, interpersonal relationship, and community connection. Also, 48 items were reduced to 31 items. Through the main test, from the 34 items were extracted 4 factors with 24 items, And then teacher-efficacy scale was developed, which included the subscales of instruction efficacy, health-service efficacy, task-interpersonal efficacy, and community connection efficacy. Conclusion: Different from that for other subject teachers, the factor structure for health teachers had 4 factors with 24 items. The scale developed in this study is consistent with health teachers' work areas, and for this reason, has significance as a adequate and valid scale to measure teacher-efficacy of health education teachers.

• 음성과학
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• 제13권2호
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• pp.7-18
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• 2006

An aphasia screening test can serve a main purpose of differentiating aphasics from non-aphasic patients in a quick as well as efficient manner. As a preliminary study for developing a standardized aphasia screening test for Korean patients, we constructed an aphasia screening test constituting items from the Paradise' Korean version-the Western Aphasia Battery(P K-WAB). All test items were analyzed in order to extract items with optimal item discrimination and adequate item difficulty indices. From the results, we were able to select some items from each subtest with optimal results of discriminant function analysis for aphasic and normal control groups. It is expected, thus, that information on the item analysis could be utilized in developing a Korean aphasia screening test.