• Korean Parent-Child Health Journal
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• v.7 no.2
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• pp.111-120
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• 2004

Purpose: This study was done to test the validity and reliability of the MMDQ for middle school students. Method: A convenience sample of 318 middle school students were asked to complete the MMDQ which consisted of 37 items and data were collected from May to June, 2004. Result: 1. Six factors for MMDQ (except insomnia, finally 36 items) were extracted through the principal component analysis with varimax rotation, and these contributed 56.7% of the variance in the total score. All 36 items in the scale loaded above .37 on one of 6 factors. 2. Factor 1 has 7 items, factor 2 has 9 items, factor 3 has 8 items, factor 4 has 5 items, factor 5 has 4 items, and factor 6 has 3 items. 3. Cronbach's alpha coefficient for internal consistency of MMDQ was .946 for the total 37 items and .88, .86, .88, .81, .70, .61 for the six factors in that order. Conclusion: MMDQ was identified its adequacy as PMS measurement tool for middle aged students in Korea. In further study, these factors would be confirmed across different samples and across different methods of data collection.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.5
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• pp.20-27
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• 2001

The purpose of this study is to investigate and compare the validity and the reliability of the visual simulation method using the internet. For this. the evaluation of the artificial and natural landscape through the medium of color slides are compared with the internet survey. Data is analysed through the comparison of t-test between the two media by landscape type, and spatial image is analysed by factor analysis algorithm. Principle component analysis using Varimax Method is applied for extraction and factor rotation respectively. The results of this study can be summarized as follows; There are no statistical differences between the two methods with artificial and natural landscape in the total data that included second tests. Factors covering the spatial image are found to be \`aesthetic\`, \`spatial shape\`, and \`familiarity\`. Total variance is obtained as 66.4%. There are no statistical differences between the two methods in 2/3 of the cases. In the case of far view of artificial landscape, the results of the t-test show that the two methods are exactly the same. Especially in the case of the artificial far landscape shows no difference of all factors between two methods. There are no differences between first and second tests of the same media and the same landscape type. And it shows the reliability of this method. These results suggest that the probability that the internet can be used as a medium of landscape evaluation and gathering information on anyone\`s landscape image. Simulation techniques with the internet survey method should be further developed for practical application.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.1
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• pp.124-132
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• 2018

This paper presents a shelf life assessment for K-1 military gas masks in the Republic of Korea using test data of Chemical Materiels Stockpile Reliability Program(CSRP). For the shelf life assessment, over 2,500 samples between 2006 and 2015 were collected from field tests and analyzed to estimate a probability of proper and improper functionality using Bayesian estimation. For this, three stages were considered; a pre-processing, a processing and an assessment. In the pre-processing, major components which directly influence the shelf life of the mask were statistically analyzed and selected by applying principal component analysis from all test components. In the processing, with the major components chosen in the previous stage, both proper and improper probability of gas masks were computed by applying Bayesian estimation. In the assessment, the probability model of the mask shelf life was analyzed with respect to storage periods between 0 and 29 years resulting in between 66.1 % and 100 % performances in accuracy, sensitivity, positive predictive value, and negative predictive value.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.213-220
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• 1999

The life data analysis of the system and component are useful to describe the result of reliability test in product life to satisfy customer's growing need and to change test specifications or design criteria by life data analysis. And vehicle durability tesr occurred market environment. In this study, a statistical analysis for the wear life of brake pad linings helped perform correlation procedure between vehicle durability test and market. B-life values of the brake pad wear life data from both vehicle durability test and marker usage were compared to determine acceleration of the test by the Weibull, normal and log-normal distribution. The acceleration coefficient of the vehicle durability test can access to evaluate design criteria of product and test specification.

• The Journal of Korean Academic Society of Nursing Education
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• v.14 no.2
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• pp.262-272
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• 2008

Purpose: This study examined the validity and reliability of the Korean version of the Revised Process of Change for Weight Control Scale (POC-WCS) in adults with metabolic syndrome. Method: A methodological research design with an exploratory factor analysis for validity and correlational coefficients for reliability was used. The Korean version of the Revised POC-WCS was translated into Korean and a translation equivalency was obtained. It was tested with one hundred and fifty-one obese adults with metabolic syndrome in a university hospital. The data were analyzed using Cronbach's alpha and Guttman coefficients and a principal component factor analysis with SPSS/WIN 12.0. Result: The factor analysis identified eight factors explaining 64.7% of the total variance. The Korean version of the Revised POC-WCS included stimulus control (9 items), dramatic relief (6 items), reinforcement management (6 items), helping relationships (4 items), consciousness raising (3 items), self liberation (3 items), self reevaluation (3 items), and social liberation (4 items). The internal consistency was acceptable with Cronbach's alpha (.94) and Guttman coefficient (.92). Conclusion: The Korean version of the Revised POC-WCS had adequate validity and reliability in adults with metabolic syndrome. It can be used to assess the strategies and processes for weight control in a variety of populations with obesity.

• Journal of Korean Academy of Nursing
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• v.29 no.2
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• pp.304-313
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• 1999

The purpose of this study is to test the reliability and validity test of PWI to utility of PWI. this newly developed by Sejin Jang which measures stress. The subject were 186 workers in service area. Cronbach's a and Guttman split-half coefficient is used to test the reliability of PWI. Factor analysis and the correlation of the GHQ-60. GHQ-30, GHQ-28, GHQ-20, and GHQ-12 with the PWI is used to convergent validity and discriminant validity. The important results of this study are as follows : Cronbach's $\alpha$ coefficient of data was 0.894 and Guttman split-half coefficient was 0.7097. The PWI was classified as 13 principle component (eigenvalue＞1.0). After exploring 4 factor structure according to previous study result, 4 factors was explained 40.5% out of the total variance. The factor 1 was explained 15.9% and then the rest three factor was 24.6%. Factor 2 and 4 showed good agreement but factor 1 and 3 did not. Depression-related items were classified two factors. Anxiety and depression-related items were loaded unifactor. It was not clear that the PWI was consist of 4 concepts(factors). The correlation of the GHQ-60, GHQ-30, GHQ-28, GHQ-20, and GHQ-12 with the PWI were 0.744~0.905. According to findings of this study. the PWI showed a high degree of validity and reliability. Thus it is recommended to use the PWI in general setting for screening for stress. In addition, it is necessary to clarify the concept of depression and anxiety. In the further study. it my be considered to the factor structure of PWI and studied to two or unidimensional factor structure.

• Journal of Korean Neuropsychiatric Association
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• v.56 no.2
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• pp.89-97
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• 2017

Objectives The Behavioral Activation of Depression Scale (BADS) has been reported to be a valid tool for assessing the different behavioral aspects of depression, such as activation, rumination or avoidance, and functional impairment. The aim of this study was to assess the reliability and validity of the Korean version of BADS (K-BADS). Methods A sample of 196 outpatients completed the K-BADS and the data were analyzed for internal consistency and factor structures. An additional 51 outpatients re-filled the K-BADS after two weeks for the test-retest reliability. To test for the validity, the Hospital Anxiety and Depression Scale (HADS), Working Alliance Inventory (WAI), Drug Attitude Inventory-10 (DAI-10), and Mindfulness Attention Awareness Scale (MAAS) were administered. Results Internal consistency of K-BADS was good (Cronbach's alpha=0.843) and principal component factor analysis revealed the four-factor structure. The K-BADS showed a reasonable test-retest reliability (r=0.863, p<0.001). The total score of K-BADS correlated significantly with the total scores of the HADS depression (r=-0.694) and HADS anxiety (r=-0.681). No correlations were found between the K-BADS and the K-WAI (r=0.170) and between the K-BADS and the K-DAI-10 (r=0.311). Conclusion The K-BADS is a reliable and valid instrument for measuring the behavioral activation for depression in Korean patients with depressive symptoms.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.569-576
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• 2017

The electromagnetic valve of pneumatic doors of EMUs has a high failure rate due to air leakage because it supplies air on and off to operate the doors repeatedly. The electromagnetic valve is a very important safety component for which a very high reliability is required because failure makes it impossible to operate the passenger cars. However, domestic urban railway operators maintain electronic valves of the EMU door under a fixed cycle with a spare period according to the full overhaul cycle of the EMU. An improvement of the current maintenance cycle was suggested based on the reliability function and mission reliability. Using the statistical program MINITAB for the operational data of EMU line 6, we analyzed the characteristics of the fault distribution and derived the shape and scale parameters of the reliability function. If we limit the specific reliability probability to under a certain failure rate and calculate its statistical parameters, we can calculate the allowable inspection period with mission reliability. Through this study, we suggested a maintenance period based on RCM (reliability centered-maintenance) to improve the reliability of electromagnetic valves from 68% to 95%.

• Journal of Power System Engineering
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• v.5 no.3
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• pp.25-30
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• 2001

The basis of all approaches to improve reliability of marine engines exists in analyzing the field data of troubles and failures in marine engines. In this paper, we analyzed the engine accidents of Korean fishing vessels for five years from 1995 to 1999, firstly according to engine systems, type of fishing vessels, engine makers, cylinder number, engine power and tonnage, secondly by using of principal component analysis method, one of multi-variate data analysis method. Finally, we proposed the measures to reduce engine accidents of fishing vessels for improvement of an environment in fishing industry.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.384-389
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• 2008

An accelerated fatigue test is essentially required to maintain the reliability of the actual structure of KTX under operation conditions. However, actual fatigue life cannot be obtained if specimens are not adequate to the conventional fatigue test. Moreover component maker did not provide data of loading stress (S) - cycles at the failure (N). In this study, we suggest a prediction method of the S-N curve for establishing an accelerating test under various load levels. Load history was acquired from the field tests. A Rainflow method was used on the cycle counting of the field load data, and then, an S-N curve was obtained through the iteration process under the condition that the damage index satisfies to 1 in the Miner's rule.