• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.152-159
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• 2014

Urea solution as a reductant of SCR has been widely used to reduce NOx emissions from diesel engine. But it has lots of problems which are freezing at low temperature due to liquid state, deposition of solid formation in the exhaust, dosing device, and complex package such as mixers for uniform concentration of ammonia. In order to overcome these obstacle, ammonium carbonate which is one of solid ammonium materials to produce ammonia gas directly by sublimation process is considered. Simple reactor with visible widow was designed to predict equilibrium temperature and pressure of ammonium carbonate. To simulate real operation conditions under automobile environment, several cycles of heating and cooling condition were settled, two different re-solidification materials were extracted from the reactor and visible window. Analytical study is performed to characterize these unknown materials by XRD(X-Ray Diffraction), FT-IR(Fourier Transform Infrared Spectroscopy), and EA(Elemental Analyzer). From analytical results, re-solidification materials from heating and cooling cycles are very similar to original material of ammonium carbonate.

• Health Policy and Management
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• v.22 no.1
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• pp.129-144
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• 2012

Purpose : The purpose of this study was to investigate the level of emotional labor and to identify affecting factors on emotional labor among one university hospital employees. Material and Method : This study was based on cross-sectional, self-administered, and Internet-based survey. The survey was conducted from Mar. 2 to Mar. 28. 2011. Total subjects were 812 employees working in one university hospital. Total response rate was 61.5%. Modified evaluation tool was used, which was originally developed by Morris and Feldman, to measure the level of emotional labor among hospital personnel. In order to identify the affecting factors on high level of emotional labor, we conducted logistic regression. The SPSS statistical software package was used to perform the statistical analysis. All statistical tests were 2-sided and a p-value<0.05 was considered statistically significant. Results : Average score of emotional labor was 3.06. Employees(3.39) who are working at the emergency department and hemodialysis room indicated the highest level of emotional labor, followed by wards(3.14), department of administration(3.14), department of ambulatory cares(3.06). The factors affecting on the high level of emotional labor were the highest level of schooling, types of department, and types of personality(p<0.05). Conclusion : The survey results showed that there was significant level of emotional labors among hospital employees. Therefore, the efforts to reduce the level of emotional labors are needed.

• Journal of Radiation Protection and Research
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• v.23 no.3
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• pp.197-210
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• 1998

Regulations for the safe transport of radioactive material published by IAEA Safety Standard Series ST-l is reviewed and summarized. Safety Series No.115(International standard of radiation protection and safety for ionizing radiation and radiation sources), which reflected the new recommendation of ICRP60 published in 1991, has been a important encouragement for IAEA to revise their safety series related to the transportation of radioactive materials. IAEA Safety, Standard Series No. ST-l is summarized by comparing IAEA Safety Series No.6 regarding radiation protection system and its implementation, technical standards of packages, concept of Q system and exemption of regulation. The IAEA regulations of transportation of radioactive materials is summarized from the viewpoint of radiation protection and safety assessment. Research on transportation system of radioactive waste is suggested as a further study.

• The Journal of the Korean dental association
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• v.55 no.1
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• pp.7-20
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• 2017

The purpose of this study is to analyze the data on the medical personnel education system and license scheme and provide the basic material for an enhanced qualification system. In China, dental education reform has been underway with a view to providing an inclusive basic medical service package to the whole country by 2020. It is also estimated that the number of Korean dental medicine students in China would be fewer. And most of them desire to get a job in China after acquiring the Chinese license, suggesting little prospect of a massive inflow into Korea in the near future. In Japan, students are required to complete a clinical training program for over 1 year after receiving licenses to become an independent practitioner. But they can apply for the Korean preliminary examination without this post-graduation process. For this reason, the quality issue in license effectiveness review has been seriously discussed. It is deemed desirable to limit the Korean accreditation to Japanese graduates from the dental schools certified by the Japanese dental accreditation body.

• Journal of the Korea Society for Simulation
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• v.15 no.4
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• pp.143-151
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• 2006

This paper deals with the simulation model for design and operations of A-Mart logistic center for low temperature products. In developed simulation model, receiving docks, digital classification system (DCS), shipping docks, material handling devices and manual sorting stations are considered. Five types of cargo such as fruits, palletized fruits, delicatessen and fisheries, vegetables and refrigerated cargoes are considered. The simulation model and process animation are developed using the simulation package ARENA. Among various design and operation alternatives consisting of the number of workers of receiving dock, allocation of receiving docks by cargo types, DCS capacity, the number of folk-lift, the number of manual sorting operators and overall layout, the best alternatives of each subsystem are selected by simulation analysis. The major performance measures such as DCS throughput, utilization of operators at each station, receiving docks utilization and folk-lift utilization are considered for the alternative evaluation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.6
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• pp.607-613
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• 2008

A monitoring system for the subway structures using prestrained FBG sensors fixed with partially stripped fibers was developed. The sensor packages had pre-strain controllable fixtures. Tensile and compressive strain of the structure could be measured without slip. The FBG sensor system was applied to the concrete lining structure in Taegu subway. Near the structure, the narrow tunnel construction, for the electric power cables and telecommunication cables, started. We wanted to measure the deformations of the subway structures due to the construction by the FBG sensor. The applied sensors had the gauge length of 1 meter to overcome the inhomogeneity of the concrete material with enough length. In order to fix tightly to the structure, the partially stripped parts of the sensor glued to the package and slip phenomenon between fiber and acrylate jacket was prevented. Prestrain of the sensor was imposed by controlling the two fixed points with bolts and nuts in order to measure compressive strain as well as tensile strain. The behavior of subway lining structure could be monitored very well.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.4
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• pp.182-190
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• 2020

This study reports a series of drop impact tests performed to generate denting damages on stiffened plates and their residual ultimate strength tests under axial compression. The models were fabricated of general structural steel, and each model has six longitudinal stiffeners and two transverse frames. Among six fabricated models, four were damaged, and two were left intact for reference. To investigate the effects of collision velocity and impact location on the extent of damage, the drop height and the impact location were changed in each impact test. After performing the collision tests, the ultimate axial compression tests were conducted to investigate the residual strengths of the damaged stiffened plates. Finite element analyses were also carried out using a commercial package Abaqus/Explicit. The material properties obtained from a quasi-static tensile tests were used, and the strain-rate sensitivity was considered. After importing the collision simulation results, the ultimate strength calculations were carried out and their results were compared with the test data for the validation of the finite element analysis method.

• Korean Journal of Acupuncture
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• v.30 no.1
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• pp.1-8
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• 2013

Objectives : The purpose of the present study was to examine statistical methods used in articles published on the Korean Journal of Acupuncture from 2007 through 2012. Methods : Statistical methods and statistical packages used in original articles applied with descriptive statistics or inferential statistics were organized. Results : Out of a total of 195 original articles, 18 articles used descriptive statistics only and 177 articles used inferential statistics. 142 articles used 12 types of statistical packages. SPSS was used most at 97 times(63.4%). The number of descriptive statistical methods used was a total of 417 and among them 193 were presented as tables(46.3%) and 224 were presented as graphs(53.7%). The number of inferential statistics applied was a total of 256 and analysis of variance was used most at 90 times(35.2%). The number of parametric statistical methods used was a total of 170(75.6%) and that of nonparametric statistical methods used was a total of 55(24.4%). Analysis of variance and two sample t-test were most employed in both clinical and non-clinical research. The number of multiple comparison methods applied was a total of 67 and the number of Scheffe methods among them was most at 26 times(37.7%). Conclusions : In the present study, statistical methods used in the journal over the last six years were examined. The result of this study is considered to be a basic material to be referred to when evaluating the quality of the medical journal.

• Korean Journal of Human Ecology
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• v.15 no.5
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• pp.859-866
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• 2006

The aim of this survey is to examine factors that influence on the perceived helpfulness in consumers' predicting its quality and safety when the country of origin (COO) of beef is declared. The data were analyzed that had collected from a consumer survey done in March 2006. 250 consumers living in Suncheon, Jeollanamdo were randomly selected as respondents. Eleven of them did not complete the survey material, so the total number of available samples were 239. All samples were estimated using proc logistic procedure of SAS package. The results indicate as follows: first, the levels of perceived helpfulness of COO in consumers' predicting beef quality and safety depend significantly on he age, the occupation, and the education level of demographic variables. Second, when analysing attitude variables to beef, the levels are significantly correlated with the respondents' ability to acquire information, their trust of information about beef, nd their interest about bovine spongiform encephalopathy(BSE). The proportional odds assumptions of models are not violated at p<0.05. Third, it is the gender, the age, and the education level of the respondents, and the respondents' ability to acquire information which significantly effect on the level of the perceived helpfulness of COO in predicting beef quality. Fourth, it is the consumer's age, their education level, and their trust of information about beef which statistically have a significant effect on the level of perceived helpfulness of COO in predicting beef safety.

• Journal of Hydrogen and New Energy
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• v.23 no.4
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• pp.300-309
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• 2012

Long endurance is a key issue in the application of unmanned aerial vehicles. This study presents feasibility test results when fuel cell system as an alternative to the conventional engine is applied for the power of the UAV after the 150W fuel cell system is developed and packaged to the 1/4 scale super cub airplane. Fuel cell system is operated by dead-end method in the anode part and periodically purged to remove the water droplet in flow field during the operation. Oxygen in the air is supplied to the stack by the two air blowers. And fuel cell stack is water cooled by cooling circuit to dissipate the heat generated during the fuel cell operation. Weight balance is considered to integrate the stack and balance of plant (BOP) in package layout. In flight performance test, we demonstrated 4 times standalone take-off and landing. In the laboratory test simulating the flight condition to quantify the energy flow, the system is analyzed in detail. Sankey diagram shows that electric efficiency of the fuel cell system is 39.2%, heat loss 50.1%, parasitic loss 8.96%, and unreacted purged gas 1.67%, respectively compared to the total hydrogen input energy. Feasibility test results show that fuel cell system is high efficient and appropriate for the power of UAV.