• Anxiety and mood
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• v.14 no.1
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• pp.7-13
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• 2018

Objective : To determine the association between occupational stress and disordered eating problem in Korean female employees. Methods : We studied 1,452 female employees who attended mental health screenings. Using the Korean Occupational Stress Scale-Short Form (KOSS-SF) and 26-item Korean version of Eating Attitude Test, occupational stress and disordered eating problem were evaluated, respectively. Sociodemographic and clinical characteristics of those with disordered eating problem were examined. Multiple logistic regression analysis was performed to determine which subscale of KOSS-SF was associated with disordered eating problem. Results : Disordered eating problem was associated with interpersonal conflict [odds ratio (OR) 1.882, 95% confidence interval (CI) 1.138-3.112] among various kinds of job stresses. Lack of reward (OR 7.164, 95% CI 1.139-45.043) and insufficient job control (OR 1.953, 95% CI 1.119-3.411) were associated with disordered eating problem in the underweight and normal weight group, respectively. Conclusion : There is an association between occupational stress and disordered eating problem among Korean female employees.

• Anxiety and mood
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• v.13 no.1
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• pp.32-38
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• 2017

Objective : Several recent studies determined the associations of job stress with depression and suicidal idea, but the association between the number of job stress components and depression remains unclear. In the present study, we investigated the associations of the number of components of job stress with depression and suicidal idea. Methods : We studied 194,226 participants who attended employee health screenings from January to December, 2014, and completely answered all the questionnaires, including the short form of Korean Occupational Stress Scale (KOSS), the Center for Epidemiologic Study-Depression (CES-D) and suicidal idea. The presence of clinical depressive symptoms was defined as a CES-D score of ${\geq}21$. The subjects in the highest quartile of each subscale of KOSS were considered as suffering from each component of job stress. Chisquare tests, t-tests and logistic regressions were performed to compare study outcomes between groups. Results : When we included all seven components of job stress, there was no significant association of the number of the components with depressive symptoms, or suicidal idea. However, the prevalence of depressive symptoms and suicidal idea was increased only in three occupational stress subscales including job demand, job insecurity and occupational climate. When we analyzed only these 3 components of job stress, the number of job stress subscales was significantly associated with depressive symptoms and suicidal idea, even after adjustment for sex and age. Conclusion : The number of components of occupational stress was associated with depressive symptoms and suicidal idea, only in the related components.

• Anxiety and mood
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• v.13 no.1
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• pp.39-45
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• 2017

Objective : Korean employees tend to release their stress by alcohol drinking. This study aimed to investigate the association between job stress and problematic drinking in Korean employees. Methods : The study participants were 72,119 employees who attended health screenings and responded to the Alcohol Use Disorder Identification Test-Korea (AUDIT-K), Korean Occupational Stress Scale-Short Form (KOSS-SF), Center for Epidemiologic Study-Depression (CES-D), Beck Anxiety Inventory (BAI) and questionnaire on suicidal ideation and sociodemographic characteristics. We investigated the sociodemographic and clinical characteristics of the problematic drinking group ($AUIDT-K{\geq}12$) and used binary logistic regression to determine the impact of job stress on problematic drinking. Results : Age, gender, marital status, education year, sleep duration, obesity, smoking, suicidal ideation, and depression and anxiety showed significant differences between the problematic drinking group and normal group. Among the various kinds of job stresses, job insecurity and lack of reward were associated with problematic drinking. Conclusion : The result of this study suggested that certain kinds of job stress might be associated with problematic drinking in Korean employees.

• Transactions of the KSME C: Technology and Education
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• v.3 no.1
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• pp.55-62
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• 2015

The liquefaction to produce LNG (liquefied natural gas) is the only practical way for mass transportation of natural gas across oceans, which accompanies considerable energy consumption in LNG plants. Power generation is one of the effective utilization ways of LNG cold energy which evolves during the vaporization process of LNG with sea water. In this work, performance analysis of two cold energy generation processes, direct expansion and organic Rankine cycles, were carried out by using Aspen HYSYS simulation. The results show that the performance of the organic Rankine cycle is superior to the direct expansion.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.434-440
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• 2007

The Effluent ground water overflows in deep and broad ground space building. Temperature of effluent ground water is in 12$\sim$18$^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effuent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and close type heat pump system using effluent ground water was installed and tested for a church building with large and deep ground space. The effluent flow rate of this building is 800$\sim$1000 ton/day. The heat pump capacity is 5RT each. The heat pump system heating COP was 3.0$\sim$3.3 for the open type and 3.3$\sim$3.8 for the close type system. The heat pump system cooling COP is 3.2$\sim$4.5 for the open type and 3.8$\sim$4.2 for close type system. This performance is up to that of BHE type ground source heat pump.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.5
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• pp.239-248
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• 2017

At the $21^{st}$ Conference of the Parties (COP) of the United Nations Climate change Conference, representatives of the 195 member countries reached an agreement requiring all participating countries, including Korea, to establish proactive measures to fight climate change. Under this vision, energy network technologies are deemed as a key site of research towards meeting this goal. Herein, the headquarters of the Korea Institute of Energy Research (KIER) is a worthy site for carrying out energy network technology research insofar as it contains various heat sources. To prepare for this research, a study was conducted analyzing the heat sources at KIER based on measured data. The study also consisted of developeding simulation models to predict the amount of energy savings that could be derived by replacing an absorption chiller/heater with an absorption heat pump during winter seasons. In our simulation results, we observed a primary energy saving ratio of 65~72% based on the water temperature from the heat source of a coal power plant.

• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.37-44
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• 2005

An experimental study was conducted to analyze performance of a heating system with variation of control logic of the system. The system uses a solar as heat source and composed with heat pump that uses R-22 as working fluid. The difference between the developed system and the commercially available heating system is working fluid. The solar assisted heating system which was widely distributed in the market uses water as a working fluid. It could be freezing in case of the temperature drops down under freezing point. The anti-freezing fluids such as methyl-alcohol or ethylene-glycol are mixed with the water to protect the freezing phenomena. However, the system developed in this study uses a refrigerant as a working fluid. It makes the system to run under zero degree temperature conditions. Another difference of the developed system compare with commercial available one is auxiliary heating method. The developed system has removed an auxiliary electric heater that has been used in conventional solar assisted heating system. Instead of the auxiliary electric heater, an air source heat exchanger which generally used as an evaporator of a heat pump was adapted as a backup heating device of the developed system. As results, an efficiency of the developed system is higher than a solar assisted heat pump with auxiliary electric heater. The merit of the developed system is on the performance increment when the system operates at a lower solar energy climate conditions. In case of the developed system operates at a normal condition, COP of the solar collector driven heat pump is higher than the air source heat exchanger driven heat pump's.

• Journal of Digital Convergence
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• v.15 no.2
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• pp.191-197
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• 2017

As individual opinions are expressed and discussed through SNS, SNS is used as a new basis to estimate the direction of public opinion. This change also appears in election. So many voters state their views through SNS, so that candidates utilize it as a new space for communication. In this paper, positive mention in SNS were collected and analysed in the course of the election of Korean 20th Congressman, to understand how the mention on election in SNS affects the result of election. This result was compared with the traditional survey on public opinion, to find out which one more corresponds to the result. In conclusion, mention in SNS coincide more with the result of elelction than the traditional survey.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.77-82
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• 2019

In this paper, we propose a new industry - university collaboration plan through the analysis of the present state of industry-academia cooperation and government support projects, and analysis of major overseas cases. The following is the plan for activating the new crop cooperation. First, it is necessary to strengthen the innovation of education system and establishment of new education course based on future demand through future-oriented industry-university cooperation. Second, active industry-academia cooperation should stimulate entrepreneurship education and entrepreneurship based on university resources. Third, it should act as an anchor of regional innovation by actively cooperating with local innovation entities. It is necessary to develop an industry-university cooperation model that can generate profits and contribute to university finance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.77-85
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• 2007

One of the most common approaches to achieve better thermal comfort with the radiant floor heating system is supply water temperature control, which is that supply water temperature is varied with outdoor air temperature. But the application of this control method was not easy, because there has been no way to determine the supply water temperature. So in this study, a comprehensive, yet simple calculation method to find out the required supply water temperature is suggested by combining the building heat loss equation and the heat emission model of hydronic radiant floor heating system for single zone. And then using this calculation method, the multizone control method is suggested and confirmed through the thermal simulation. It is shown that indoor air temperature is stably maintained around the set point.