• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.4
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• pp.297-308
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• 2003

Face-bow is used to transfer models to the articulator in diagnosing the patient or treating problems associated with occlusion. However, there have been few reports on the reliability of the face-bow procedure and the relationship between the experience of the operator and the reliability of the face-bow procedure. The purposes of this study are to examine the reliability of the face-bow procedure and to evaluate whether the face-bow transferring has any training effect. Nine dentists working at M hospital conducted a face-bow transfer in one patient having a normal dentition and interdental relationship. The procedure was done two times a week for four weeks. The maxillary model was mounted to the articulator every time, then the landmarks on the maxillary right first molar, the maxillary left central incisor, and the maxillary left first molar were measured with a special three-dimensional instrument. These data were input into a computer, and evaluated statistically. The results were as follows ; 1. When examined with ANOVA test, the results were p=0.2040 in maxillary right first molar, p=0.0578 in maxillary left incisor, and p=0.1433 in maxillary left first molar. There was no significant(0< $p{\leq}0.05$). 2. Training 1) The correlation coefficient between trial and rejection was -0.578 when analyzed with T-distribution. The more we tried, the less errors we found. 2) When the S.D. of the first three trials was compared to the S.D. of the last three trials in face-bow transfer, the results showed that the former was larger than the latter in thirty-nine times, and the latter was larger than the former in fifteen times. The more we tried face-bow transfer, the less errors we found. 3. When the S.D. of x, y, z coordinates were examined, the S.D. of x coordinates had the largest measurement in five times, the S.D. of y coordinates had the largest measurement in four times, and the S.D. of z coordinates had the largest measurement in nine times. The possibility which the error can occur in z coordinate was the highest.

• Journal of muscle and joint health
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• v.7 no.1
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• pp.5-24
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• 2000

Middle age for women is one of the most important stages of the whole normal life span and has unique problems concerning the psychological and physical health, specifically degenerative musculoskeletal diseases. Therefore middle age women should prepare in order to lead a healthy and fruitful life as they enter/begin old age. As the population of middle age women increase, the demands of nurses who care for this age group also continue to glow. Nurses must be interested in this middle age group of women in Korea. This study was designed to identify the extent of family support and self-esteem of the middle age women with degenerative musculoskeletal diseases and the relationship between them and nurse's contribution to middle age women's health promotion that maintain and promote qualify of her life. The population of this study was 112 women aged 40-60, attending the out patient clinic one University Hospital and one Hospital, in Pusan. The data was collected from 1st August to the 30th of September, 1998 by using 36 items questionnaire. The instrument used for measuring family support was of Chai's(1983) FSS which was modified by Kang's(1984) Family Support Scale. And that for self-esteem was Rosenberg's(1965) Self-esteem Scale. The reliability of Chai's FSS and Rosenberg's instruments were tested by Cronbach's alpha and showed that they were 0.93 and 0.89 each respectively. Data was analyzed by descriptive statistics, t-test, ANOVA, and Pearson's Correlation Coefficient using the SPSS computer program. The results of the study were summarized as follows : 1. The mean score of the perceived family support was $39.31{\pm}9.42$. 2. The mean score of the perceived self-esteem was $33.16{\pm}6.75$. 3. Statistically significant factors influencing the family support among sociodemographic variables was satisfaction of marriage(F=-3.069, p<0.003). 4. Statistically significant factors influencing the self-esteem among sociodemographic variables were age(F=3.992, p=0.000), education(F=2.260, P=0.026), housing (F=-1.987, P=0.049) and satisfaction of marriage(F=-2.305, P=0.023). 5. There was a significant correlation between family support and self-esteem (r=.621, p<.000). In conclusion, perceived the family support was important for middle age women to increase their self-esteem. Nurses should be aware of the necessity of family support in the supportive nursing of middle age women and should be able to make a plan to educate the family about supporting the wife/mother. The continuing study of the health promotion of middle age women to find out variables influencing middle age women' health must continue.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1161-1170
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• 2011

This paper presents a solution to the inverse problem for the service boundary conditions of thermal-flow and structure analysis in a catalyst substrate. The exhaust-gas purification efficiency of a catalyst substrate is influenced by the shape parameter, catalyst ingredients and so on and is estimated by the thermal flow uniformity. The formulations of the inverse problem of obtaining the thermal-flow parameters (inlet temperature, velocity, heat of reaction, convective heat-transfer coefficient) and the direct problem of estimating from a given outlet temperature distribution are described. An experiment was designed and the response-surface optimization technique was used to solve the proposed inverse problem. The temperature distribution of the catalyst substrate was obtained by thermal-flow analysis for the predicted thermal-flow parameters. The thermal stress and durability assessments for the catalyst substrate were performed on the basis of this temperature distribution. The efficiency and accuracy of the inverse approach have been demonstrated through the achievement of good agreement between the thermal-flow response surface model and the results of experimental vehicle tests.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.413-421
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• 2014

Desiccant cooling system is an air conditioning system that uses evaporative cooler to cool air and it can perform cooling by using heat energy only without electrically charged cooler. Thus, it can solve many problems of present cooling system including the destruction of ozone layer due to the use of CFC[chloro fluoro carbon] affiliated refrigerants and increase of peak power during summer season. In this study, cooling performance and exergy analysis was conducted in order to increase efficiency of desiccant cooling system. Especially, using exergy analysis based on the second law of thermodynamics can resolve the issue related to system efficiency in a more fundamental way by analyzing the cause of exergy destruction both in whole system and each component. The purpose of this study is to evaluate COP[coefficient of performance], cooling capacity and exergy performance of desiccant cooling system incorporating a regenerative evaporative cooler in various regeneration temperature and outdoor air conditions.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.247-256
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• 2003

FEM analyses which are based on modified Cam-clay theory have been generally used in such cases as analyses of stability and displacement fur embankment construction on soft clays. However, the Modified Cam Clay Model can generate some problems in anisotropic stress conditions of field because the critical state theory has been developed through many laboratory tests in isotropic conditions. Thus, the applicability on the prediction of undrained shear strength and pore water pressure which was based on the critical state theory was evaluated by triaxial tests and numerical analyses in isotropic and anisotropic conditions. Used samples often come out in domestic area, together with general low plastic clays which are showing dilatant behavior in shearing process. They were evaluated by laboratory tests and FEM based on MCCM. From the results of test and numerical analysis, the predictions of undrained strength in low plastic clays well coincided with each other in both isotropic and anisotropic conditions. However, the generation of porewater pressure was often overestimated during undrained shearing in anisotropic conditions. The results can generate the errors in the prediction of stress path of field sites during loading such as construction of embankment on soft clays because the field is subjected to anisotropic conditions during loading.

• The Journal of Industrial Distribution & Business
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• v.9 no.7
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• pp.53-59
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• 2018

Purpose - This study examines the effect of control-ownership wedge on stock crash risk. In Korea, controlling shareholders have exclusive control rights compared to their cash flow rights. With increasing disparity, controlling shareholders abuse their power and extract private benefits at the expense of the minority shareholders. Managers who are controlling shareholders of the companies tend not to disclose critical information that would prevent them from pursuing private interests. They accumulate negative information in the firm. When the accumulated bad news crosses a tipping point, it will be suddenly released to the market at once, resulting in an abrupt decline in stock prices. We predict that stock price crash likelihood due to information opaqueness increases as the wedge increases. Research design, data, and methodology - 831 KOSPI-listed firm-year observations are from KisValue database from 2005 to 2011. Control-ownership wedge is measured as the ratio (UCO -UCF)/UCO where UCF(UCO) is the ultimate cash-flow(control) rights of the largest controlling shareholder. Dependent variable CRASH is a dummy variable that equals one if the firm has at least 1 crash week during a year, and zero otherwise. Logistic regression is used to examine the relationship between control-ownership wedge and stock price crash risk. Results - Using a sample of KOSPI-listed firms in KisValue database for the period 2005-2011, we find that stock price crash risk increases as the disparity increases. Specifically, we find that the coefficient of WEDGE is significantly positive, supporting our prediction. The result implies that as controlling shareholders' ownership increases, controlling shareholders tend to withhold bad news. Conclusions - Our results show that agency problems arising from the divergence between control rights and cash flow rights increase the opaqueness of accounting information. Eventually, the accumulated bad news is released all at once, leading to stock price crashes. It could be seen that companies with high control-ownership wedge are likely to experience future stock price crashes. Our study is related to a broader literature that examined the effect of the control-ownership wedge on stock markets. Our findings suggest that the disparity is a meaningful predictor for future stock price crash risk. The results are expected to provide useful implications for firms, regulators, and investors.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.958-964
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• 2002

To select the irradiation-induced marker components from volatile flavor compounds in irradiated chicken, and complement the extraction problems of liquid continuous extraction (LLCE) method, the volatile compounds of irradiated (0,1,3,5 and 10 kGy) chicken were analyzed by Purge and Trap (P&T) and gas chromatography/mass spectrometry (GC/MS) methods. A total of 119 compounds were detected in irradiated chicken, and these compounds were composed mainly of 7 aldehydes,22 ketones,8 alcohols,30 esters,36 hydrocarbons,8 aromatic compounds and 8 miscellaneous compounds. Among these, only 21 compounds were detected in both LLCE and P&T methods, and the 98 other were detected in omly P&T method. Among volatile compounds detected in irradiated chicken, only 3 compounds such as hexene (r=0.96, p<0.01), propanol (r=0.93, p<0.05) and 1,3-bis(1,1-dimethylethyl) benzene (r=0.96, p<0.05) were newly selected as marker compounds in irradiated chicken by P&T method, which showed significant and high positive correlation coefficient in the change of relative concentration according to the increment of irradiation dosage.

• Journal of Korean Society of Forest Science
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• v.97 no.6
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• pp.617-626
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• 2008

Recently, it has been issued whether the current permission standards for forest land-use conversion is adequate or not. This study was aimed at evaluating the propriety of the current permission standards using the Delphi technique, which is one of survey techniques regarding experts's opinions. The results of the survey indicated that the standards related to the connection development restriction and the height of the first berm were underrated in most of the evaluation factors. The size limit and the altitude restriction of the land-use conversion also have a low propriety or applicability due to their vagueness. In case of average slope, its applicability was rated as significantly low because there is no standardized method for estimating or verifying the average slope. A statistical analysis based on coefficient of variation and one-way ANOVA were conducted to examine whether each group of experts agree with these survey results. It is appeared that the survey using Delphi technique could successfully achieved an agreement from each group of experts. Overall, evaluation factors considered in this study seems to be effective to verify the problems of each standards and to guide to improvement of the standards.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.456-464
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• 2016

Increasing the strength of structural materials allows their self-weight to be reduced and this, in turn, enables the structures to satisfy esthetic requirements. The yield strength of high-performance steel is almost 480 MPa, which is approximately 50% higher than that of general structural steel. The use of high strength materials, however, makes the sections more slender, which can potentially result in significant local stability problems. The strength of slender element sections might be governed by their elastic buckling behavior, and the elastic buckling strength is very sensitive to the boundary conditions. Because the web provides the boundary conditions of the compressive thin-flange, the stiffness of the web can affect the elastic buckling strength of the flange. In this study, therefore, the effects of the flange and web slenderness ratios on the elastic flange local buckling of I-girders subjected to a pure bending moment were evaluated by finite element analysis (FEA). The analysis results show that the elastic local buckling strength and buckling modes were affected not only by the web support conditions, but also by the flange and web slenderness ratios.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.626-633
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• 2020

This study examined the behavior of the ground by comparing the methods using the results of the Terzaghi formula and the ground investigation data and method considering the dilatancy effect for a circular tunnel using the finite element method. In the case of the Terzaghi formula, the tunnel load can be overestimated and cause overdesign. The method using the results of the ground investigation data cannot be applied when a reasonable coefficient of earth pressure is not determined. This is because it behaves completely differently from the actual behavior, and unexpected problems can occur. In the case of the method considering the dilatancy effect, however, both the strength enhancement effect can be considered through the dilatancy angle and relative density. Therefore, the tunnel load was calculated most reasonably using the method considering dilatancy. Finite element analysis using the geotechnical survey results showed that the tensile stress acts at the top of the tunnel when the upper soil of the tunnel is shallow. On the other hand, additional verification is necessary, such as a comparison with the field measurement results. Through additional research, if normalized, the tunnel load can be calculated reasonably at the time of tunnel design, and safe and economical design is possible.