• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2400-2404
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• 2011

Power spectral density (PSD) model of irregularities for the maglev test track is presented. Track irregularities (gauge, cant, twist and vertical) were calculated from the survey data of sleepers on the test track. PSD model was constructed from the estimated PSDs of each track irregularities. Versine (gauge, cant, twist, vertical and lateral) of the track is obtained and their PSDs were estimated, too. Presented PSD model can be used for the analysis of levitation stability and ride quality of the maglev system.

• 한국병원경영학회지
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• 제13권4호
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• pp.76-100
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• 2008

The purpose of this research is to identify causalities among service quality, service value, customer satisfaction and customer loyalty and to compare the causalities between in-patients and out-patients. A multi-group structural equation model was used to test the hypothesis of conceptual model. Empirical results indicate that two factors such as assurance and empathy have direct impact on service value and customer satisfaction in both the patients. In the results of multi-group comparison test, however, the path coefficients from service value to customer loyalty and from customer satisfaction to customer loyalty were different across the two groups. In out-patients, customer loyalty is more positively related with service value. In in-patients, customer loyalty is more positively related with customer satisfaction. It is proven that service quality influences customer loyalty. Therefore To compete successfully in today's volatile & competitive medical markets, the hospital needs to manage the service quality, considering the type of patients.

• 한국군사과학기술학회지
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• 제23권4호
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• pp.389-398
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• 2020

Test cases in the existing weapon system software were created manually by the tester analyzing the test items defined in the software integration test procedure. However, existing test case generation method has two limitations. First, the quality of test cases can vary depending on the tester's ability to analyze the test items. Second, excessive time and cost may be incurred in writing test cases. This paper proposes a method to automatically generate test cases based on the requirements model and specifications to overcome the limitations of the existing weapon system software test case generation. Generate test sequences and test data based on the use case event model, a model representing the requirements of the weapon system software, and the use case specification specifying the requirements. The proposed method was applied to 8 target models constituting the avionics control system, producing 30 test sequences and 8 test data.

• 한국IT서비스학회지
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• 제7권2호
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• pp.197-221
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• 2008

This study is to identify quality factors having influence upon mobile internet service performance theoretically, derive the research model and the hypotheses concerning the cause and effect relationship between these factors and service performance and then analyze them empirically. In order to enhance the model's explanation power, trust and cognitive engagement as interviewing variables are included in the model. The theoretical background of this study was brought from relevant literature in the areas of the theory of reasoned action(TRA). technology acceptance model(TAM), product selection model, cognitive absorption theory and etc. The research model and hypotheses were statistically investigated and analysed through convergent and discriminant validity test, reliability test, and path analyses by means of statistical packages SPSS(12.0) and LISREL(8.72). For these empirical analyses. data were collected through the field survey of 373 users who were willing to continuously use the mobile internet services. Based on the results of the analyses, theoretical and practical significance and future study direction were suggested. The results of this study will be helpful to giving a guideline to companies such as mobile telecom, mobile contents provider and mobile handset manufactures when they have to establish the mobile Internet service marketing strategies.

• 품질경영학회지
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• 제34권3호
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• pp.19-30
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• 2006

For highly reliable products, it is difficult to assess the lifetime of the products with traditional life tests. Accordingly, a recent approach is to observe the performance degradation of product during the test rather than regular failure time. This study compares performances of three methods(i.e. the approximation, analytical and numerical methods) to estimate the parameters and quantiles of the lifetime when the time-to-failure distribution follows Weibull and lognormal distributions under a random coefficient degradation rate model. Numerical experiments are also conducted to investigate the effects of model error such as measurements in a random coefficient model.

• 한국물환경학회지
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• 제20권4호
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• pp.321-326
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• 2004

The objective of this study is to test the applicability of neural network models to forecast water quality at Naesa and Pyongchang river. Water quality data devided into rainy day and non-rainy day to find characteristics of them. The mean and maximum data of rainy day show higher than those of non-rainy day. And discharge correlate with TOC at Pyongchang river. Neural network model is trained to the correlation of discharge with water quality. As a result, it is convinced that the proposed neural network model can apply to the analysis of real time water quality monitoring.

• 한국직업건강간호학회지
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• 제20권1호
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• pp.35-45
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• 2011

Purpose: The purpose of this study was to propose and to test a predictive model that could explain the workers' quality of life. Methods: Data were collected using self-report questionnaires from 901 workers in Daejeon, Korea. The questionnaires included nine measured variables (safety culture, self-efficacy, activity of occupational health provider, knowledge in occupational health, age, health promotion behavior, workplace environment, health level, and quality of life), as revised PRECEDE model has suggested. The collected data were analyzed using SPSS/WIN 15 and AMOS 6.01 version. Results: Based on the constructed model, behavior, environment, and health were found to have significant direct effect on quality of life. Indirect factors were perceived biological, predisposing, reinforcing, and enabling. The proposed model was concise and extensive in predicting quality of life of the participants. The final modified model yielded GFI=.85, AGFI=.89, NFI=.79, and RMSEA=.11 and exhibited good fit indices. Conclusion: Findings of this study may contribute to development of effective nursing interventions for promoting quality of life in workers.

• 품질경영학회지
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• 제49권3호
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• pp.341-358
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• 2021

Purpose: After product development, a Reliability Demonstration Test(RDT) is performed to confirm that the target life has been achieved. In the RDT, there are cases where the test equipment cannot accommodate all samples. Therefore, this study considers a test method to most economically demonstrate the target life of the product at a certain confidence level when the sample size is larger than the capacity of the test equipment. Methods: If the sample size is larger than the capacity of the test equipment, test equipments may be added or the test time of individual samples may be increased. So the test method is designed to cover this situation with limited capacity. A zero-failure test method is applied as a test method to RDT. To minimize the cost, the test cost is defined and the cost function is obtained. Finally, we obtain the optimal test plan. Results: A zero-failure test method is designed when the sample size is larger than the capacity of the test equipment, and the expected total cost is derived. In addition, the process of calculating the appropriate sample size, test time, and number of test equipment is illustrated through an example, and the effects of model parameters to the optimal solutions are investigated numerically. Conclusion: In this paper, we study a zero-failure RDT with test equipment that has limited capacity. The expected total cost is derived and the optimal sample size, test time, and number of test equipment are determined to minimize the expected total cost. We also studied numerical examples and for further studies, we can relax some restrictions in the test model and optimize the test method.

• 품질경영학회지
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• 제19권1호
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• pp.65-71
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• 1991

According to characters of software, the methods of evaluating reliability are different. The purpose of this study was to develop application software used in the field and to set up reliability model which failure density was used so that in the process of test, developer and user may apply a point of time to field business and to apply developed model which real data use used.

• 품질경영학회지
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• 제41권2호
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• pp.277-288
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• 2013

Purpose: This study aims to analyze the success factors of information systems and the moderating effect of individual factors in mandatory environment. Methods: In order to test the model, a questionnaire survey is delivered from salespersons of an insurance company in Seoul, Korea. 200 questionnaires are finally analyzed. Structural Equation Modeling (SEM) is adopted to analyze the data and Smart PLS 2.0 is used for examining the moderator effect. Results: The extended model proposed in this paper adopted individual factors and examined their moderator effect among constructs. An empirical test is carried out accordingly in order to test the model proposed in this paper. The results reveal that individual factors (i.e. Computer Self-Efficacy, Anxiety, Personal Innovativeness in IT) have a significant moderating effect on individual performance in the environment of mandatory information system usage. Conclusion: This paper extended the research field of information system success model to information systems in mandatory environment regarding differences of individual factors.