• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2885-2890
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• 2011

본 연구에서는 최근 증가하고 있는 대심도역사의 화재위치에 따른 연기확산영향에 대하여 분석하였다. 시뮬레이션모델은 신금호 역사(5호선, 깊이 46m)를 대상으로 하였으며, 화재위치에 따른 연기확산 영향을 분석 하였다. 현장조사 및 실측을 통하여 계측된 실제 역사의 제연팬에 관한 데이터를 화재시뮬레이션 조건으로 적용하였다. 역사전체를 해석 대상으로 하여 총 400만개의 격자를 사용하였으며, 화재위치에 따른 연기확산 영향 비교를 위하여 화재 시나리오를 작성하여 Case별로 화재해석을 수행하였다. 계산 효율을 높이기 위하여 MPI병렬처리기법을 사용하였으며 해석코드는 LES(large eddy simulation) 기법을 주로 사용하는 FDS5 code를 사용하였다.

• Safety and Health at Work
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• 제6권2호
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• pp.104-113
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• 2015

Background: Given the long hours on the road involving multiple and interacting work stressors (i.e., delivery pressures, irregular shifts, ergonomic hazards), commercial drivers face a plethora of health and safety risks. Researchers goal was to determine whether and to what extent long-haul trucker work schedules influence sleep duration and quality. Methods: Survey and biometric data collected from male long-haul truck drivers at a major truckstop in central North Carolina over a six month period. Results: Daily hours worked (mean = 11 hours, 55 minutes) and frequency of working over government-mandated daily HOS regulations (23.8% "frequently or always") were statistically significant predictors of sleep duration. Miles driven per week (mean = 2,812.61), irregular daily hours worked (63.8%), and frequency of working over the daily hour limit (23.8% "frequently or always") were statistically significant predictors of sleep quality. Conclusion: Implications of findings suggest a comprehensive review of the regulations and operational conditions for commercial motor vehicle drivers be undertaken.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.941-949
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• 2020

This study aims to investigate the factors which impact the possibility of Environmental Management Accounting (EMA) implementation in automobile companies in Vietnam. A survey was carried out with automobile enterprises' managers, getting 198 usable respondents, with data and theoretical model analyzed by using SPSS with EFA method. Results indicated that in Vietnamese automobile enterprises, the possibility of EMA implementation was driven by elements including motivation to reduce production costs, reactions to environmental issues, compliance to legislation, procedures and processes in the working environment which they are in business. The government and professional institutions should play a vital role in promoting EMA practices by issuing specific guidelines and continuous training. Besides, tax authorities should apply the favor policies such as tax incentives to stimulate interest enterprises to implement EMA. However, this study's results only reflect about 63.7% of the impact to the implementation of EMA in Vietnamese automotive enterprises, so there are still some other factors that should be found out in the future researches. This is the first attempt to systematically analyze enterprises' perception and willingness to apply EMA in Vietnamese automobile industry. This study contributes to not only the existing empirical literature of EMA but also enterprises' managers in Vietnam and other transitional economies.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.655-660
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• 2001

The performance test of a centrifugal compressor for APU(Auxiliary Power Unit) which is developed by the collaborative research of KARI and Samsung TechWin has been conducted. The investigated compressor consists of a curved inlet, a centrifugal impeller, a channel diffuser and a plenum chamber. The experiments were carried out in an open-loop centrifugal compressor test rig driven by a turbine. For three different diffusers, overall performance data were obtained at 80%, 90% and 97% of design speed. For the initially designed wedge-type diffuser, test results showed that the compressor was operated at a higher mass flow rate than the design requirement. By reducing the diffuser throat area, the compressor operating range was shifted to lower mass flow rate range. The test result of redesigned wedge-type diffuser showed high pressure loss. To reduce the diffuser loss, diffuser inlet radius was increased and airfoil-type of diffuser was adopted. This airfoil-type diffuser showed reasonal results in terms of design requirement.

• 보건행정학회지
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• 제14권1호
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• pp.89-120
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• 2004

The purpose of this empirical study is to test hypotheses in order to identify the cost drivers that drive indirect costs in general hospitals in Korea. In various cases' studies, it has been suggested that overhead costs are driven by volume and complexity variables, how they are structurally related and how the cost impacts of these variables can be A unique feature of the research is the treatment of complexity as an endogenous variable. It is hypothesized that level of hospital complexity in terms of the number of services provided(i.e., “breath" complexity) and the intensity of individual estimated in practice. overhead services(ie., “depth" complexity) are simultaneous determined with the level of costs needed to support the complexity. Data used in this study were obtained from the Database of Korean Health Industry Development Institute, Health Insurance Review Agency and analyzed using simultaneous equation model, path model. The results found those volume and complexity variables are all statistically signi-ficance drivers of general hospital overhead costs. This study has documented that the level of service complexity is a significant determinant of hospital overhead costs, caution should be exercised in interpreting this as supportive of the cost accounting procedures associated with ABC. with ABC.

• Child Health Nursing Research
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• 제26권3호
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• pp.357-365
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• 2020

Purpose: The aim of this study was to investigate internet addiction among middle school students and to examine the mediating effects of social support in the relationships of self-efficacy and self-control with internet addiction. Methods: The participants in the study were 119 middle school students in J city. The measurements included a self-efficacy scale, a self-control scale, a social support scale, and the Internet Addiction Scale for Youth. Data were analyzed using the independent t-test or Mann-Whitney U test, one-way analysis of variance, the Scheffé test, Pearson correlation coefficients, and multiple-regression using SPSS version 22.0. Mediation effects were analyzed by the Sobel test and Baron and Kenny's hierarchical analysis technique. Results: Significant correlations were found among self-efficacy, self-control, and internet addiction. Social support had partial mediating effects in the relationship between self-efficacy and internet addiction, as well as in the relationship between self-control and internet addition. Conclusion: In order to prevent internet addiction, the promotion of interactions among peers, which is a component of social support, is particularly important. It is also necessary to promote face-to-face activities that can strengthen relationships. The findings suggest that intensifying social support may help reduce the level of internet addiction in middle school students.

• 한국치위생학회지
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• 제13권4호
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• pp.659-668
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• 2013

Objectives : The purpose of this study is to analyze the causes of stress driven by the national examination and to find out correlation between stress factors and students' general characteristics. Methods : Data were collected from self-reported questionnaires by dental hygiene students in D university in February, 2012. Results : Those having good high school GPAs (p<.05) and high preliminary test scores (p<.01) towards dental hygienist (p<.05). National license examination was the most stressful factor for 54.2% of the students. Much more stressful pressure goes to students of non-scheduled admission (p<.01), students who graduated from vocational high schools(p<.01), students with good high school GPAs (p<.05), and having high preliminary test scores(p<.05). Most of the students tended to bear the burden on national written examination with an average of 4.17. The most difficult subject was oral biology introduction (average 4.52). Oral biology introduction was more stressful to students of early admission, students graduating from vocational high schools (p<.05), students with good high school GPAs (p<.05), and students who had relatively low preliminary test scores (p<.001). Conclusions : It is crucial to reduce stress factors and to develop related programs.

• 한국비블리아학회지
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• 제3권1호
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• pp.39-55
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• 1978

The following results have been driven out from a survey of the actual conditions of the public libraries service in Korea, made through questionnaire in reference with the actual service for youth that are presently done by the foreign countries' libraries, in order to prepare a perfect and objective base in establishing a service activities of the public libraries in this country: (1) It was found that the public libraries' loarning hours during the week days which accords with the schooling hours of the schools are shown to 50 %. On Saturdays during Summer season seven libraries and during Winter season twelve libraries would close their loaning before 17 : 00 hours, and on Holidays and Sundays fifteen libraries are not doing their loarning. (2) The followings are the present status of the service activities for the youth by the public libraries: a. It was found that they do introduction activity (50 %) of newly published books as a service for inducing reading interestings of the youth, and except this it was found that others are on beginning. b. The service activities by the data for the visual and auditory sense are almost negelected. and the rate of doing such activity is shown to 9.74%. c. It has been found that little information service activity is for inducing the youth to the libraries. d. As a cooperative activity with the school's, a passive service activity to have pursuaded to visit the public libraries by each class, are mostly being done (27.27%). Some research meeting for solving all the matters between the school libraries are not held mostly.

• Geomechanics and Engineering
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• 제20권4호
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• pp.345-358
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• 2020

Numerous studies have repeatedly demonstrated the efficiency of using skirts to increase the bearing capacity and to reduce settlement of shallow foundations subjected to static loads. However, no efforts have been made to study the efficiency of using these skirts to reduce settlement produced by machine vibration, although machines are very sensitive to settlement and the foundations of these machines should be designed properly to ensure that the settlement produced due to machine vibration is very small. This research has been conducted to investigate the efficiency of using skirts as a technique to reduce the settlement of a strip foundation subjected to machine vibration. A two-dimensional finite element model has been developed, validated, and employed to achieve the aim of the study. The results of the analyses showed that the use of skirts reduces the settlement produced due to machine vibration. However, the percentage decrease of the settlement is remarkably influenced by the density of the soil and the frequency of vibration, where it rises as the frequency of vibration increases and declines as the soil density rises. It was also found that increasing skirt length increases the percentage decrease of the settlement. Importantly, the results obtained from the analyses have been utilized to derive new dynamic impedance values that implicitly consider the presence of skirts. Finally, novel design equations of dynamic impedance that implicitly account to the effect of the skirts have been derived and validated utilizing a new intelligent data driven method. These new equations can be used in future designs of skirted strip foundations subjected to machine vibration.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.534-544
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• 1995

Many electronic products employ menu-driven interfaces for user-system dialogue. Unlike the software user interfaces, a small single-line display, such as a Liquid Crystal Display, is typically used to present menu items. Since the display can show only a single menu item at a time, more serious navigation problems are expected with single-line display menus(SDM). This study attempts to provide a set of unique guidelines for the design of the SDM based on empirical results. A human factors experiment was conducted to examine the effects of four design variables: menu structure, user experience, navigation aid, and number of targets. The usability of design alternatives was measured quantitatively in four different aspects, which were speed, accuracy, inefficiency of navigation, and subjective user preference. The analysis of variance was used to test the statistical effects of the design variables and their interaction effects. A set of design guidelines was drawn from the results which can be applied to the design of human-system interfaces of a wide variety of electronic consumer products using such displays. Since more generalized guidelines could be provided by constructing prediction models based on the empirical data, some powerful performance models are also required for the SDM. As a preliminary study, a survey was done on the performance models for ordinary computer menus.