• Proceedings of the KSR Conference
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• 2005.05a
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• pp.151-156
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• 2005

The objective of this study is to devise an accident scenario analysis method adept at creating accident scenarios at the Preliminary Hazard Analysis(PHA) step of a hazard analysis for railway system. This approach was inspired by the Quality Function Deployment(QFD) method, which is conventionally used in quality management and was used at the systematic accident scenario analysis(SASA) for the design of safer products. In this study, the QFD provides a formal and systematic schema to devise accident scenarios while maintaining objective. The accident scenario analysis method first identifies the hazard factors that cause railway accidents and explains the situation characteristics surrounding the accident. This method includes a feasibility test, a clustering process and a pattering process for a clearer understanding of the accident situation. Since this method enables an accident scenario analysis method to be performed systematically as well as objectively, this method is useful in building better accident prevention strategies. Therefore, this study can serve to reduce railway accident and be an effective tool for a hazard analysis.

• Journal of Power System Engineering
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• v.16 no.5
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• pp.63-69
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• 2012

This paper presents an analysis on the induction heating of ring flange for wind farm. Ring flange is used for the connection of poles when building a column of wind power plant. Heat treatment of ring flange with the diameter of ${\O}1,000mm$ has been considered. For analysis on the induction heating, FEA is used. Firstly, electromagnetic filed analysis was performed to get the induction current distribution on the steel, After that, heat transfer analysis was performed using the magnetic filed analysis results. for more precise analysis, some measurement for permeability has been performed and the measurement data was used during the analysis. From the analysis, we get the temperature distribution on the ring flange.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2B
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• pp.225-236
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• 2008

The techniques to calculate the probability precipitation for the design of hydrological projects can be determined by the point frequency analysis and the regional frequency analysis. Probability precipitation usually calculated by point frequency analysis using rainfall data that is observed in rainfall observatory which is situated in the basin. Therefore, Probability precipitation through point frequency analysis need observed rainfall data for enough periods. But, lacking precipitation data can be calculated to wrong parameters. Consequently, the regional frequency analysis can supplement the lacking precipitation data. Therefore, the regional frequency analysis has weaknesses compared to point frequency analysis because of suppositions about probability distributions. In this paper, rainfall observatory in Korea did grouping by cluster analysis using position of timely precipitation observatory and characteristic time rainfall. Discordancy and heterogeneity measures verified the grouping precipitation observatory by the cluster analysis. So, there divided rainfall observatory in Korea to 6 areas, and the regional frequency analysis applies index-flood techniques and L-moment techniques. Also, the probability precipitation was calculated by the regional frequency analysis using variable kernel density function. At the results, the regional frequency analysis of the variable kernel function can utilize for decision difficulty of suitable probability distribution in other methods.

• Journal of the Korea Furniture Society
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• v.21 no.1
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• pp.26-39
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• 2010

This is a leading study to replace the structural analysis methodology on the specific traditional joint by a numerical analysis. Tests were carried out to test the compressive methodologies with the numerical results. The Japanese larch was used as a sample. The Orthotropic property of wood was specifically considered for the finite element numerical analysis. Linear numerical analysis and non-linear numerical analysis for the BEAM element and the two SOLID elements of ANSYS were used to analyze the compressive performance. In addition, more finely divided elements were used to raise the accuracy of the numerical result. Finally, the statistically significant differences were tested between that of the analytical and numerical results. It could be concluded that the SOLID 64 element shows the most optimum result when the non-linear analysis with the more finely divided element was used. However, finely dividing of the element is a considerable time consuming process, and it is quite difficult to raise the accuracy of the non-linear numerical analysis. Therefore, if considering the vertical displacement to be of the only interest, the BEAM element is more efficient than the SOLID element because the BEAM element is reflected as a simple line, which is less time consuming and difficult in dividing the elements. But, the BEAM element cannot accurately model the knot as a strength defect factor which is an important property in the orthotropic property of wood. Therefore, the SOLID element should be used to model the strength defect factor, knot, as it can be efficiently applied on the structural size flexure member which could be more strongly effected by the knot. In addition, it is useful at times when the failure types of members are to be more closely investigated, as the SOLID element is able to examine the local stress distribution of the member. The conclusion drawn by this study is of the good concordance between analytical results and numerical results of compressive wood members, but how orthotropic properties should only be considered. The numerical analysis on the specific Korean traditional joints will be based on the current study results.

• Environmental Engineering Research
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• v.22 no.2
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• pp.216-223
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• 2017

For the prediction of the ventilation rate for removing the non-isothermal concentrated fume from the semi-enclosed space, the computational fluid dynamics (CFD) analysis was done. Securing the proper ventilation conditions in emergency state such as in fire is crucial factor for the protection of the resident in the space. In the analysis for the determining the proper ventilation rate, the experimental study had the limitation for simulating the versatile conditions of fume development. The theoretical and computational method had been chosen as the alternate tool for the experimental analysis. In this study, the CFD analysis was done on the defined model which already had been done the experimental analysis by the previous workers. By comparing the prediction on the plume heights and the ventilation rates by the CFD analysis at, and in the parametric model of $1m^3$ with those of the previous experimental works, the feasibility of the computational analysis was evaluated. For the required ventilation rate analyzed by the CFD analysis was over predicted in 7.1% difference with that of the experimental results depending on the different plume height. With the comparison with the analytical Zukoski model at, the CFD analysis on the ventilation was under predicted in 8.3%. By the verification of the feasibility of the CFD analysis, the extended analysis was done for getting the extra information such as the water vapor distribution and $CO^2$ distribution in the semi-enclosed spaces.

• Lingua Humanitatis
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• v.2 no.2
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• pp.301-319
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• 2002

In a recent paper, I have proposed an analysis concerning propositions and 'that'-clauses as a solution to Kripke's puzzle and other similar puzzles, which I now call 'the Indefinite Description Analysis of Belief Ascription Sentences.' I have listed some of the major advantages of this analysis besides its merit as a solution to the puzzles: it is amenable to the direct-reference theory of proper names; it does not nevertheless need to introduce Russellian (singular) propositions or any other new entities. David Lewis has constructed an interesting argument to refute this analysis. His argument seems to show that my analysis has an unwelcome consequence: if someone believes any proposition, then he or she should, ipso facto, believe any necessary (mathematical or logical) proposition (such as the proposition that 1 succeeds 0). In this paper, I argue that Lewis's argument does not pose a real threat to my analysis. All his argument shows is that we should not accept the assumption called 'the equivalence thesis': if two sentences are equivalent, then they express the same proposition. I argue that this thesis is already in trouble for independent reasons. Especially, I argue that if we accept the equivalence thesis then, even without my analysis, we can derive a sentence like 'Fred believes that 1 succeeds 0 and snow is white' from a sentence like 'Fred believes that snow is white.' The consequence mentioned above is not worse than this consequence.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1590-1597
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• 2004

Three methods of design sensitivity analysis for structures such as numerical method, analytical method and semi-analytical method have been developed for the last three decades. Although analytical design sensitivity analysis can provide very exact result, it is difficult to implement into practical design problems. Therefore, numerical method such as finite difference method is widely used to simply obtain the design sensitivity in most cases. The numerical differentiation is sufficiently accurate and reliable fur most linear problems. However, it turns out that the numerical differentiation is inefficient and inaccurate in nonlinear design sensitivity analysis because its computational cost depends on the number of design variables and large numerical errors can be included. Thus the semi-analytical method is more suitable for complicated design problems. Moreover, semi-analytical method is easy to be performed in design procedure, which can be coupled with an analysis solver such as commercial finite element package. In this paper, implementation procedure fur the semi-analytical design sensitivity analysis outside of the commercial finite element package is studied and the computational technique is proposed for evaluating the partial differentiation of internal nodal force, so called pseudo-load. Numerical examples coupled with commercial finite element package are shown to verify usefulness of proposed semi-analytical sensitivity analysis procedure and computational technique for pseudo-load.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.492-497
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• 2004

Three methods for design sensitivity such as numerical differentiation, analytical method and semi-analytical method have been developed for the last three decades. Although analytical design sensitivity analysis is exact, it is hard to implement for practical design problems. Therefore, numerical method such as finite difference method is widely used to simply obtain the design sensitivity in most cases. The numerical differentiation is sufficiently accurate and reliable for most linear problems. However, it turns out that the numerical differentiation is inefficient and inaccurate because its computational cost depends on the number of design variables and large numerical errors can be included especially in nonlinear design sensitivity analysis. Thus semi-analytical method is more suitable for complicated design problems. Moreover semi-analytical method is easy to be performed in design procedure, which can be coupled with an analysis solver such as commercial finite element package. In this paper, implementation procedure for the semi-analytical design sensitivity analysis outside of the commercial finite element package is studied and computational technique is proposed, which evaluates the pseudo-load for design sensitivity analysis easily by using the design variation of corresponding internal nodal forces. Errors in semi-analytical design sensitivity analysis are examined and numerical examples are illustrated to confirm the reduction of numerical error considerably.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.11
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• pp.1179-1189
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• 2003

This study had a focus on service quality, customer satisfaction and relationship orientation. The subjects of this study were: 1) to examine the conceptual structure of service quality perceived by males consumers of character clothing brands, 2) to examine of the service quality on customer satisfaction, and 3)to examine relationship between customer satisfaction and relationship orientation. The questionnaire was collected between October, 28 and November, 8 in 2002. Samples of 271 respondents were obtained. The sample consisted of males in their twenties and thirties who had a experience on buying character clothing brands in Seoul. To analyze the data, reliability analysis, percentage, frequency analysis, factor analysis, correlation analysis, and regression analysis were applied. The results were as followings: 1) As a result of factor analysis, the service quality were identified by four dimensions: environmental service, personal service, products service, and promotion service. 2) As a result of correlation analysis and regression analysis, the service quality had a positive influence on customer satisfaction. Especially products service was the most important factor for customer satisfaction, followed by environmental service. 3) As a result of correlation analysis, customer satisfaction had a positive influence on relationship orientation.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.2
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• pp.1-16
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• 2018

Purpose : This meta-analysis was aimed at guiding future research in stroke treatment and to provide real-world data relating to the effects of aquatic exercise therapy on balance in patients with chronic stroke. Methods : We performed a meta-analysis comprising 22 studies involving aquatic exercise therapy performed between 2006 and 2017. A meta-analysis software program was used to calculate the mean effect size, effect size by intervention, and effect size by outcome. We also performed a meta-regression analysis and an analysis of publishing bias. Results : The mean effect size was 0.563. The effect size by outcome was observed to be the largest for the functional reach test, followed by the Berg balance scale, balance equipment, the Timed Up and Go test and one leg standing. Meta-regression analysis showed that effect size increased with an increase in the duration, number, length of exercise session. Conclusion : Aquatic exercise therapy appears to show a moderate effect on balance in patients with chronic stroke. A meta-analysis is warranted for further research to determine the effects of aquatic exercise on walking, muscle strength, and range of motion.