• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.6 s.261
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• pp.531-538
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• 2007

In this study, an air conditioning system using carbon dioxide as a refrigerant was developed for automotive cabin cooling. Experiments have been carried out to examine the steady state and dynamic characteristics of this system. The system consists of a compressor, a gas cooler, an evaporator, an expansion device, an internal heat exchanger and an accumulator. The compressor is a variable displacement type, driven by the electric motor, and the gas cooler and the evaporator are aluminum extruded heat exchangers of micro channel type. The $CO_2-refrigerant$ charge, the compressor speed, the air inlet temperature of the gas cooler, the air inlet temperature and the air flow rate of the evaporator and the cooling load are varied and the performance of the system is experimentally investigated. As the compressor speed increased, cooling capacity increased, but the coefficient of performance was deteriorated. As the cabin air temperature or the air flow rate to the cabin was set high, both the cooling capacity and the COP increased. In the cool down experiment with 1.0 or 2.0 kW of heat load, the dynamic characteristics of the air-conditioning system were investigated. For a given capacity of compressor, cool down speed was monitored, and the temperature change was acceptable fur low heat load condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.149-156
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• 2006

This paper investigates the steady state combustion characteristics of LPG homogeneous charge compression ignition(HCCI) engine with variable valve timing(VVT) and dimethyl ether(DME) direct injection, to find out the benefits in exhaust gas emissions. VVT is one of the attractive ways to control HCCI engine. Hot internal residual gas which is controlled by VVT device, makes fuel is evaporated easily, and ignition timing is advanced. Regular gasoline and liquefied petroleum gas(LPG) were used as main fuel and dimethyl ether(DME) was used as ignition promoter in this research. Operating range and exhaust emissions were compared LPG HCCI engine with gasoline HCCI engine. Operating range of LPG HCCI engine was wider than that of gasoline HCCI engine. The start of combustion was affected by the intake valve open(IVO) timing and the ${\lambda}TOTAL$ due to the latent heat of vaporization, not like gasoline HCCI engine. At rich operation conditions, the burn duration of the LPG HCCI engine was longer than that of the gasoline HCCI engine. CAD at 20% and 90% of the mass fraction burned were also more retarded than that of the gasoline HCCI engine. And carbon dioxide(CO2) emission of LPG HCCI engine was lower than that of gasoline HCCI engine. However, carbon oxide(CO) and hydro carbon(HC) emission of LPG HCCI engine were higher than that of gasoline HCCI engine.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.178-185
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• 2006

This paper investigates the steady-state combustion characteristics of the Homogeneous charge compression ignition(HCCI) engine with variable valve timing(VVT) and dimethyl ether(DME) direct injection, to find out its benefits in exhaust gas emissions. HCCI combustion is an attractive way to lower carbon dioxide($CO_2$), nitrogen oxides(NOx) emission and to allow higher fuel conversion efficiency. However, HCCI engine has inherent problem of narrow operating range at high load due to high in-cylinder peak pressure and consequent noise. To overcome this problem, the control of combustion start and heat release rate is required. It is difficult to control the start of combustion because HCCI combustion phase is closely linked to chemical reaction during a compression stroke. The combination of VVT and DME direct injection was chosen as the most promising strategy to control the HCCI combustion phase in this study. Regular gasoline was injected at intake port as main fuel, while small amount of DME was also injected directly into the cylinder as an ignition promoter for the control of ignition timing. Different intake valve timings were tested for combustion phase control. Regular gasoline was tested for HCCI operation and emission characteristics with various engine conditions. With HCCI operation, ignition delay and rapid burning angle were successfully controlled by the amount of internal EGR that was determined with VVT. For best IMEP and low HC emission, DME should be injected during early compression stroke. IMEP was mainly affected by the DME injection timing, and quantities of fuel DME and gasoline. HC emission was mainly affected by both the amount of gasoline and the DME injection timing. NOx emission was lower than conventional SI engine at gasoline lean region. However, NOx emission was similar to that in the conventional SI engine at gasoline rich region. CO emission was affected by the amount of gasoline and DME.

• Journal of the Korean Home Economics Association
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• v.47 no.9
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• pp.15-26
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• 2009

The main purpose of this study was to speculate how psychological state of adolescent students has changed their school uniform style. For the study, the distinctive characteristics during adolescence stage were theoretically examined. Through the examination, this study found four interests in fashions and school uniforms. For the purpose, this study conducted interviews with grade 2 students in a total of six coeducation secondary schools in Seoul, Gyeongki and Gwangju using a questionnaire. The survey period ranged from December 15 2008 to December 24 2008 and a total of 1196 were used for a final analysis. This study extracted factors as Principal Components Analysis and used Varimax for orthogonal rotation analysis. To measure confidence, it used Cronbach's a test to item internal consistency. For data analysis, it used SPSS WIN 12.0 and for hypothesis analysis, frequency analysis, cross analysis, independent t-test, and one-way ANOVA were conducted. For posterior analysis, it used Sheffe test. The results are as follows: First, the interests in fashion and school uniforms differed depending on their own tastes, but these interests were more influenced by environment around school. Secondly, the boy subjects were more aggressive towards repairs their uniforms than the girls, which suggested that boys had stronger desire to show themselves to others and more satisfaction from repairs their uniforms than the girls. Based on the results, this study concluded as follows: We should pay attention to preventing deformation in original design of school uniforms while expanding options to have variable designs or to change detailed part of design. So, there will be no additional uniform mending expense and financial loss to parents, and students will be more satisfied with their school uniforms.

• Research in Community and Public Health Nursing
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• v.10 no.2
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• pp.307-319
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• 1999

The purpose of this study was to identify the major factors affecting performance in health promoting lifestyle of industrial workers. The subjects for this study 241 workers employed in S company in T city and were obtained by a convenience sample. Data were collected from March 2 to April 28. 1998. The collected data were analyzed using frequency. percent. mean. cronbach alpha. t-test. ANOVA. Person coefficients of correlation. Duncan test. stepwise multiple regression with an SPSS program. The results of this are summarized as follows. 1) The average score of performance in the health promoting lifestyle was 2.62. The variable with the highest degree of performance was harmonious relationship. whereas the one with the lowest degree was professional health maintenance. 2) Performance in the health promoting lifestyle was significantly correlated with self esteem, internal health locus of control and powerful others health locus of control. 3) Performance in the health promoting lifestyle was significantly correlated with such demographic variables as age. religion, education level. marital state. family number. types of dwelling. 4) The most important factor that affect performance in the health promoting lifestyle was powerful others health locus of control and self esteem. On the basis of this study. other factors affecting others health promoting lifestyle should be identified.

• Geotechnical Engineering
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• v.12 no.4
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• pp.21-32
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• 1996

To predict the stress-strain behavior of the soil more approximately, the concept of the critical state soil mechanics was added to the plasticity increment theory in the bounding surface Plasticity model. This model was constituted with two ellipse and one hyperbola in older to describe the behaviour of the isotropically consolidated soil. Thus, this model is very complicate due to the various parameters used. Therefore, the accurate understanding and skill of the theory is required in order to apply this model to the practical geotechnical problems. In the present paper, the bounding surface shape paraiheter R and A, the mapping center parameter C among various parameters used were varied and the results were numerically analized. Finally, each sensitivity with respect to monotonic and cyclic loading was analized and the range of the value of the each parameter was proposed.

• Journal of Distribution Science
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• v.21 no.12
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• pp.71-81
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• 2023

Purpose: This research aims to analyze the influence of greed, opportunity, need, exposes on fraudulence financial reporting by using the distribution of political connections as a moderating variable. Research design, data, methodology: Using data collected from 180 respondents who were leaders involved in financial reports in state-owned companies and manufacturing companies in South Sulawesi, Indonesia. Data analysis using SEM PLS. Results: The results of this research show that greed, opportunity, need, exposes, political connections have a significant positive effect on fraudulence financial reporting. Political connection is able to moderate greed, need, exposes to fraudulence financial reporting. Furthermore, political connections are unable to moderate the opportunity for fraudulence financial reporting in company. Conclusion: Greed, opportunities, needs, exposes can influence someone to carry out financial fraud reporting in the company because of internal or external factors that cause someone to commit fraud. Every perpetrator of fraud should be subject to punishment or sanctions if proven to have committed fraud. Political connections can influence fraudulent financial reporting due to the potential for intervention and political pressure that can affect the integrity of financial reporting. Political connections are able to moderate greed, need, exposes against fraudulent financial reporting.

• Journal of Korean society of Dental Hygiene
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• v.7 no.1
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• pp.41-51
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• 2007

The purpose of this study was to provide information about the development of curricula geared toward improving the oral health of college students and of oral-health education programs in an effort to teach college students to be knowledgeable about oral health throughout their lives. The subjects in this study were 455 students at three different colleges in Gyeonggi province, on whom a survey was conducted. As for the basic oral health care of the college students investigated, 54.5 percent had ever visited a dental clinic over the last year, and 34.7 percent had their teeth scaled over the last year. Regarding self-awareness of current oral health state, 77 percent felt there s something wrong with their oral health. Concerning the correlation of their oral health behavior and knowledge to each selected variable, better internal and external locus of control led to better oral health promotion behaviors and better oral health knowledge. As to their self-perception of oral health and influential factors, better toothbrushing, better dietary habits and periodical oral examination, which belonged to oral health promotion behaviors, were followed by better oral health locus of control, and higher concern for oral health led to better oral health locus of control as well. Better toothbrushing, better dietary habits, periodical oral examination and better internal locus of control were concurrent with higher interest in oral health. Better external locus of control and stronger concern for oral health were accompanied by better oral health promotion behaviors.

• The Korean Journal of Nuclear Medicine
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• v.19 no.2
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• pp.69-79
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• 1985

To evaluate the effect of dopaminergic activity on aldosterone secretion, the plasma renin activity, serum cortisol and aldosterone were measured by radioimmunoassay in 6 normal controls and 12 patients who had hyponatremia and generalized edema or ascites with possible condition with secondary aldosteronism before and after(15, 30, and 60 min) 15 mg of metoclopramide by iv bolus injection and same method with 500 mg of L-dopa by per oral in 6 normal controls and 12 patients with edema ascites. The result were as follows; 1) The basal level of PRA was higher in patients rather than normal controls but PRA was not influenced by MC or L-dopa administration on both normal controls and patients group. 2) The serum cortisol level was significantly elevated at 30 min after MC injection compared with basal level in normal controls but no significant change was noted in patients group. After L-dopa administration the serum cortisol level was not changed in both normal controls and patients group. 3) The serum aldosterone level was significantly elevated in 15, 30 and 60 min after MC injection in normal controls, and there also same tendency of aldosterone secretion was noticed in patients group. On the other hands, there was no changes in aldosterone level in both normal controls and patients group with L-dopa administration. Above result means that MC stimulate aldosterone secretion by dopaminergic antagonist and aldosterone secretion in normal subject is controlled by maximal tonic dopaminergic inhibition. In edematous patients, however, both of the dopaminergic inhibitory and stimulating effect of PRA, ACTH etc on the aldosterone secretion seems to be variable.

• Korean Journal of Occupational Health Nursing
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• v.11 no.1
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• pp.13-30
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• 2002

Industrial shift workers feels suffer mental stresses which are caused by unfamiliar day sleep, noisy environment, sleeping disorder by bright light, unusual contacts with family, difficulty in meeting with friends or having formal social meetings and other social limitations such as the use of transportation. Such stresses influence health of the workers negatively. Thus the health promotion policy for shift workers should be made considering the workers' ways of living and shift work specially. This study attempted to provide basic information for development of the health promotion program for industrial shift workers by examining predictive factors influencing health promotion behaviors of those workers. In designing the study, three power generation plants located in Pusan and south Kyungsang province were randomly selected and therefrom 280 workers at central control, boiler and turbine rooms and environmental chemistry parts whose processes require shift works were sampled as subjects of the study. Data were collected two times from September 17 to October 8, 1999 using questionnaires with helps of safety and health managers of the plants. The questionnaires were distributed through mails or direct visits. Means for the study included the measurement tool of health promotion behavior provided by Park(1995), the tool of self-efficacy measurement by Suh(1995), the tool of internal locus of control measurement by Oh(1987), the measurement tool of perceived health state by Park(1995) and the tool of social support measurement by Paek(1995). The collected data were analyzed using SPSS program. Controlling factors of the subjects were evaluated in terms of frequency and percentage ratio Perceived factors and health promotion behaviors of the subjects were done so in terms of mean and standard deviation, and average mark and standard deviation, respectively. Relations between controlling and perceived factors were analyzed using t-test and ANOVA and those between perceived factors and the performance of health promotion behaviors, using Pearson's Correlation Coefficient. The performance of health promotion behaviors was tested using t-test, ANOVA and post multi-comparison (Scheffe test). Predictive factors of health promotion behavior were examined through the Stepwise Multiple Regression Analysis. Results of the study are summarized as follows. 1. The performance of health promotion behaviors by the subjects was evaluated as having the value of mean, $161.27{\pm}26.73$ points(min.:60, max.:240) and average mark, $2.68{\pm}0.44$ points(min.:1, max.:4). When the performance was analyzed according to related aspects, it showed the highest level in harmonious relation with average mark, $3.15{\pm}.56$ points, followed by hygienic life($3.03{\pm}.55$), self-realization ($2.84{\pm}.55$), emotional support($2.73{\pm}.61$), regular meals($2.71{\pm}.76$), self-control($2.62{\pm}.63$), health diet($2.62{\pm}.56$), rest and sleep($2.60{\pm}.59$), exercise and activity($2.53{\pm}.57$), diet control($2.52{\pm}.56$) and special health management($2.06{\pm}.65$). 2. In relations between perceived factors of the subjects(self-efficacy, internal locus of control, perceived health state) and the performance of health promotion behaviors, the performance was found having significantly pure relations with self-efficacy (r=.524, P=.000), internal locus of control (r=.225, P=.000) and perceived health state(r=.244, P=.000). The higher each evaluated point of the three factors was, the higher the performance was in level. 3. When relations between the controlling factors(demography-based social, health-related, job-related and human relations characteristics) and the performance of health promotion behaviors were analyzed, the performance showed significant differences according to marital status (t=2.09, P= .03), religion(F=3.93, P= .00) and participation in religious activities (F=8.10, P= .00) out of demography-based characteristics, medical examination results (F=7.20, P= .00) and methods of the collection of health knowledge and information(F=3.41, P= .01) and methods of desired health education(F=3.41, P= .01) out of health-related characteristics, detrimental factors perception(F=4.49, P= .01) and job satisfaction(F=8.41, P= .00) out of job-related characteristics and social support(F=14.69, P= .00) out of human relations characteristics. 4. The factor which is a variable predicting best the performance of health promotion behaviors by the subjects was the self-efficacy accounting for 27.4% of the prediction, followed by participation in religious activities, social support, job satisfaction, received health state and internal locus of control in order all of which totally account for 41.0%. In conclusion, the predictive factor which most influence the performance of health promotion behaviors by shift workers was self-efficacy. To promote the sense, therefore, it is necessary to develop the nursing intervention program considering predictive factors as variables identified in this study. Further industrial nurses should play their roles actively to help shift workers increase their capability of self-management of health.