• Title/Summary/Keyword: theory test

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A Simplified Phenomenological Theory of Viscosity for Liquid Metals

  • Kim, Won Su;Chae, Dong Sik
    • Bulletin of the Korean Chemical Society
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    • v.22 no.1
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    • pp.43-45
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    • 2001
  • This study simplifies the phenomenological theory of viscosity previously proposed by the present authors. This simplified theory has only two thermodynamic properties and one parameter, as opposed to its predecessor, which has many, allowing for easy calculation of the liquid viscosities. The viscosity of liquid metals, an excellent test for checking the validity of the liquid theory, can be calculated using the equation based on the simplified theory. The calculated results by the current theory turn out to be good for the liquid metals, including sodium, potassium, rubbidium, cesium, lead and mercury.

Analysis of the difficulty and discrimination of paper-based tests and computer-based tests according to item response theory: focusing on the National Dental Technician Examination (문항반응이론에 따른 지필 시험과 컴퓨터적용 시험의 난이도와 변별도 분석: 치과기공사 국가시험을 중심으로)

  • Hwang, Kyung-Sook
    • Journal of Technologic Dentistry
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    • v.44 no.3
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    • pp.104-110
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    • 2022
  • Purpose: This study analyzes the difficulty and discrimination of the paper-based test (PBT) and the computer-based test (CBT) according to item response theory, focusing on the National Dental Technician Examination. Methods: A mock test was conducted from September 15 to 23, 2020, and the final 179 (1 out of 180 absentees)people were the subjects of this study. Both frequency analysis and factor analysis were performed. The collected data were analyzed using IBM SPSS Statistics ver. 18.0 (IBM) and jMetrik programs. The significance level was set to 0.05. Results: The difficulty of the mock test was more easily responded to in CBT. It was also predicted that the CBT could better measure the ability of test takers than the PBT could. Conclusion: The difficulty, discrimination, and reliability of the questions were not affected by the examination method through the mock test. The feasibility of a future change to the CBT was confirmed by the National Dental Technician Examination.

Ductile Fracture Behaviour under Mode I Loading Using Rousellier Ductile Damage Theory

  • Oh, Dong-Joon;Howard, I.C.;Yates, J.R.
    • Journal of Mechanical Science and Technology
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    • v.14 no.9
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    • pp.978-984
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    • 2000
  • The aim of this study is to investigate the ductile fracture behaviour under Mode I loading using SA533B pressure vessel steel. Experiments consist of the Round Notch Bar Test (RNB), Single Edge Crack Bending Test (SECB), and V-Notch Bar Test (VNB). Results from the RNB test were used to tune the damage modelling constant. The other tests were performed to acquire the J-resistance curves and to confirm the damage constants. Microstructural observation includes the measurement of crack profile to obtain the roughness parameter. Finally, simulation using Rousellier Ductile Damage Theory (RDDT) was carried out with 4-node quadrilateral element ($L_c=0.25\;mm$). For the crack advance, the failed element removal technique was adopted with a ${\beta}$ criterion. In conclusion, the predicted simulation using RDDT showed a good agreement with the experimental results. A trial using a roughness parameter was made for a new evaluation of J-resistance curve, which is more conservative than the conventional one.

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A Study on Data Clustering Method Using Local Probability (국부 확률을 이용한 데이터 분류에 관한 연구)

  • Son, Chang-Ho;Choi, Won-Ho;Lee, Jae-Kook
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.1
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    • pp.46-51
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    • 2007
  • In this paper, we propose a new data clustering method using local probability and hypothesis theory. To cluster the test data set we analyze the local area of the test data set using local probability distribution and decide the candidate class of the data set using mean standard deviation and variance etc. To decide each class of the test data, statistical hypothesis theory is applied to the decided candidate class of the test data set. For evaluating, the proposed classification method is compared to the conventional fuzzy c-mean method, k-means algorithm and Discriminator analysis algorithm. The simulation results show more accuracy than results of fuzzy c-mean method, k-means algorithm and Discriminator analysis algorithm.

Measurement of Springback Ratio Using Winding Bend Rig (감아굽힘 실험장치를 이용한 스프링백 비의 측정)

  • 김용우
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.88-94
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    • 2000
  • A winding bend rig for measurement of springback ratio is made. It measures the bending angles before and after release of bending load which bends specimens with keeping a constant curvature. Thus the springback ratio can be obtained by using this bend rig. Analytical explanations for the spring back are tried by employing simple beam theory. For the analytical calculations with the theory, Young's modulus, fracture strain and stress-strain curve are necessary and these data are obtained from a tensile test. Using both of the beam theory and the results of tensile test, the springback ratio is also calculated. Comparisons of the two springback ratios, one is obtained from bending test and the other from tensile test, show a good agreement.

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Development and Evaluation of the Family Relations Enhancement Program - Applied to Rural Women in Gyeonggi do - (가족관계 증진 프로그램 개발 및 효과검증 - 경기지역 농촌여성을 대상으로 -)

  • Choi Kyu-Reon
    • The Korean Journal of Community Living Science
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    • v.17 no.2
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    • pp.31-48
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    • 2006
  • The purpose of this study is to develop and evaluate the program which aims at providing a better understanding of family role, establishing a desirable value of being good spouse and good parent, and good daughter/mother in-law and determine effects of the program on rural women in Gyeonggi do. Based on the strong & healthy family perspective, personality types theory, coping stress theory, anger control method, communication & conflict solution theory(eg; Minnesota Couple Communication Program), cognitive behavior theory, and relations enrichment theory, 6 session program was developed. The title of 6 sessions were 'Making happy family', 'Family communication', 'Coping parent-child relation stress', 'Coping conjugal personality difference', 'Becoming a good mother/daughter in-law', and 'Dissolving family conflict'. 188 women surveyed were asked to participate in the program held at 5 city located in Gyeonggi do from Jun. 22 to July, 15. 2005, with two days(3 session a day and 120 minutes per session based). The effectiveness of this program was evaluated by pre-test, post test through 188 rural women and it was analyzed by paired t-test and program evaluation questionnaire was also investigated. The major results were as follows: This program was effective in improving spouse relation satisfaction, child relation satisfaction, daughter/mother in-law relation satisfaction, their effort for making happy family, self-esteem, and depression tendency. Future research and practical implications were added.

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Introducing an Online Measurement System Using Item Response Theory and Computer Adaptive Testing Methods for Measuring the Physical Activity of Community-Dwelling Frail Older Adults

  • Choi, Bong-sam
    • Physical Therapy Korea
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    • v.26 no.3
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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.

Interpretation of coefficient of consolidation from CRS test results

  • Jia, Rui;Chai, Jinchun;Hino, Takenori
    • Geomechanics and Engineering
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    • v.5 no.1
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    • pp.57-70
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    • 2013
  • Constant rate of strain (CRS) consolidation tests were conducted for undisturbed Ariake clay samples from three boreholes in Saga Plain of Kyushu Island, Japan. The coefficients of consolidation ($c_{\nu}$) were interpreted from the CRS test results by small- and large-strain theory. Large-strain theory was found to interpret smaller $c_{\nu}$ values and less strain rate effect on $c_{\nu}$ than that by small-strain theory. Comparing the theoretical strain distributions within a soil specimen to those obtained by numerical simulation shows that the small-strain theory can be used only for the dimensionless parameter $c_{\nu}/\dot{\varepsilon}H_0^2{\geq}50$ (where $\dot{\varepsilon}$ is strain rate and $H_0$ is the specimen height), and the large-strain theory can be used for a larger range of strain rates. Applying the criterion to undisturbed Ariake clay with a $c_{\nu}$ value of about $1{\times}10^{-7}\;m^2/s$, it is suggested that the large-strain theory should be adopted for calculating the $c_{\nu}$ value when $\dot{\varepsilon}$ > 0.03%/min.

A Study on Permissible Current of Low Impedance Cable (저임피던스 케이블의 허용전류에 대한 연구)

  • 김동식;박복기;이종찬;이관우;박대희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.513-515
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    • 1999
  • In this study, we evaluated the relation of the test and theory of low impedance cable As the result We could obtained the result in accordance the test with theory in 85 ~ 95% tolerance . Test method measured the relation of the current and temperature of cable jacket in using CT to put in 3 phase AC current simultationiously. The current and temperature of it was calculated in according to JCS- l68D

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Effects of an Educational Intervention Based on the Protection Motivation Theory and Implementation Intentions on First and Second Pap Test Practice in Iran

  • Dehdari, Tahereh;Hassani, Laleh;Hajizadeh, Ebrahim;Shojaeizadeh, Davoud;Nedjat, Saharnaz;Abedini, Mehrandokht
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.17
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    • pp.7257-7261
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    • 2014
  • Background: Few Iranian women take the Papanicolaou test despite its important role in preventing cervical cancer. This study aimed to determine the effectiveness of an educational intervention based on the protection motivation theory (PMT) variables and implementation intentions in the first and second Pap test practice among Iranian women. Materials and Methods: In this quasi-randomized controlled trial, 200 women who were referred to 30 primary health care clinics in Tehran were randomly selected. PMT variables and Pap test practice were measured at baseline and again after 3 and 15 months. The 4-week educational intervention program was conducted for the intervention group. Results: Following the intervention, the mean scores of self-efficacy, perceived vulnerability, and behavior intention variables were significantly higher in the intervention group when compared to the control group (p<0.05). No significant differences were found in the perceived severity, response efficacy, response cost, and fear between the two groups following the intervention. Higher percent of women in the intervention group had obtained first and second Pap test compared to the controls. Conclusions: The PMT and implementation intentions provide a suitable theory-based framework for developing educational interventions regarding Pap test practice in Iran.