• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.67-73
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• 2013

This experimental work described the effect of flow control valve type on the performance of wobble plate type fuel pump for the stable DME fuel supply. In order to study this, different four types of flow control valves (ITV, SCV, IMV and MPROP) were installed on the wobble plate fuel pump, and fuel flow rate, torque, and temperature variation of pump were investigated under various operating conditions by using pump performance test system. It was revealed that wobble plate type fuel pump worked well with ITV and SCV control valve, and the flow rate and torque of fuel pump was in proportion to the value of valve open duty. The maximum flow rate and torque of fuel pump were achieved around the 50% duty of control valve. Temperature variation at all pump measuring points were under $60^{\circ}C$ which is acceptable.

• Journal of Internet Computing and Services
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• v.15 no.5
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• pp.33-41
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• 2014

The purpose of this study is to provide statistical analysis based suggestions on effective methods to take advantage of social network service (SNS) for educational purposes based on investigations of undergraduate students with high utilization of SNS. To achieve this, we conducted an open questionnaire survey and qualitatively analyzed the data using NVivo 10 program. Additionally, to visualize the analysis by education subject of the SNS educational methods, we have divided the data into 3 categories of teacher, student and common area. As a result, our analysis showed that the exchange opinions and discussions, information sharing and learning of contents of questions and answers, surveys, intimacy formation, counseling etc. were of the common area. Furthermore, teacher area included the notice announcement, teaching materials sharing, real-time assessment (quiz), attendance check, assignment grading and feedback, etc. Finally the student area was of project activities (group/individual), prepare and review the shared data, video self learning, peer review and feedback of projects, lecture evaluation, etc.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.529-539
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• 1998

The effects of membrane surface charge originated from lipid head groups on ion channels were tested by analyzing the activity of single large conductance $Ca^{2+}-activated\;K^+$ (maxi K) channel from rat skeletal muscle. The conductances and open-state probability ($P_o$) of single maxi K channels were compared in three types of planar lipid bilayers formed from a neutral phosphatidylethanolamine (PE) or two negatively-charged phospholipids, phosphatidylserine (PS) and phosphatidylinositol (PI). Under symmetrical KCl concentrations $(3{\sim}1,000\;mM)$, single channel conductances of maxi K channels in charged membranes were $1.1{\sim}1.7$ times larger than those in PE membranes, and the differences were more pronounced at the lower ionic strength. The average slope conductances at 100 mM KCl were $251{\pm}9.9$, $360{\pm}8.7$ and $356{\pm}12.4$ $(mean{\pm}SEM)$ pS in PE, PS and PI membranes respectively. The potentials at which $P_o$ was 1/2, appeared to have shifted left by 40 mV along voltage axis in the membranes formed with PS or PI. Such shift was consistently seen at pCa 5, 4.5, 4 and 3.5. Estimation of the effect of surface charge from these data indicated that maxi K channels sensed the surface potentials at a distance of $8{\sim}9\;{\AA}$ from the membrane surface. In addition, similar insulation distance ($7{\sim}9\;{\AA}$) of channel mouth from the bilayer surface charge was predicted by a 3-barrier-2-site model of energy profile for the permeation of $K^+$ ions. In conclusion, despite the differences in structure and fluidity of phospholipids in bilayers, the activities of maxi K channels in two charged membranes composed of PS or PI were strikingly similar and larger than those in bilayers of PE. These results suggest that the enhancement of conductance and $P_o$ of maxi channels is mostly due to negative charges in the phospholipid head groups.

• Korean Journal of Construction Engineering and Management
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• v.6 no.1 s.23
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• pp.117-124
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• 2005

The development of computer and information technology in Korean construction industry is accelerating its speed while the education of Universities regarding to those technology is hardly catching up. Students graduated from schools are having difficulties in adapting themselves into the technology and as a result the industry is operating its own educational problem for the newcomers. This research develops the educational program of computer and information technology in school and therefore enhance the adaptability of the students for the industry. The program is open from 2002 up to 2004 liking two courses and including 10 modules and a project. The educational program consists of computer labs and lectures or seminars. The result of the educational program enables students to understand the computer and information technology used in the industry, an to improve the interest and skills of those, and additionally to motivate themselves into participating the continuous research and development of the technology.

• Journal of Periodontal and Implant Science
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• v.50 no.3
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• pp.197-206
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• 2020

Purpose: The aim of this study was to determine the impact of different compressive forces on deproteinized bovine bone mineral (DBBM) particles covered by native bilayer collagen membrane (NBCM) during alveolar ridge preservation (ARP) in the molar area, and to identify any histomorphometric and clinical differences according to the compressive force applied. Methods: Sockets were filled with DBBM after tooth extraction, and different compressive forces (30 N and 5 N, respectively) were applied to the graft material in the test (30 N) and control (5 N) groups. The DBBM in both groups was covered with NBCM in a double-layered fashion. A crossed horizontal mattress suture (hidden X) was then made. A core biopsy was performed using a trephine bur without flap elevation at the implant placement site for histomorphometric evaluations after 4 months. The change of the marginal bone level was measured using radiography. Results: Twelve patients completed the study. The histomorphometric analysis demonstrated that the mean ratios of the areas of new bone, residual graft material, and soft tissue and the implant stability quotient did not differ significantly between the groups (P>0.05). However, the mean size of the residual graft material showed a significant intergroup difference (P<0.05). Conclusions: The application of 2 compressive forces (5 N, 30 N) on particulate DBBM grafts during open-healing ARP in the posterior area led to comparable new bone formation, implant feasibility and peri-implant bone level.

• Culinary science and hospitality research
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• v.17 no.2
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• pp.126-139
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• 2011

This study was conducted on the 4 year university students majoring in the culinary practice to survey the recognition levels of the culinary practice education with the purpose of searching for a development plan of the culinary education. The recognition levels of the culinary practice education according to the types of sex, grade and alma mater are as follows. The interest and necessity of the culinary practice education was very high while the performance degree of the culinary practice education was felt insufficient. For the efficient culinary practice education, they recognized that theoretical education and practice demonstrations are required and hoped to focus on hotel cooking and certified technician cooking. In addition, they hoped to be provided with a place for teacher's detailed practice demonstrations and supplementary practice. According to the variables, positive responses were given from male students, high grade students and vocational school students. In conclusion, if chances are given to display achievement desire self-directly through increasing practical training, development and application of various programs, operation of open practice classes and culinary organization reflecting social changes in the education courses, the culinary practice education is considered to be more vitalized.

• Korean Journal of Child Studies
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• v.6 no.2
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• pp.21-33
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• 1985

This study was conducted to ascertain whether a didactic mode of instruction, favored students who indicated a preference for left hemispheric information processing. The subjects were 50 fifth grade students whose California Achievement Test score percentile ranks were between 50 - 80. They were randomly selected from one elementary school in Chapel Hill, NC, USA. All Ss completed the Form CC of "Your Style of Learning and Thinking" (Torrance and McCarthy, 1980) which is a paper/pencil inventory designed to categorize the subjects according to their hemispheric preference for processing information; right hemisphere, left hemisphere, and integrated. Then all Ss received a didactic mode of instruction, a verbal question/answer followed by teacher's reading of a fictional animal story, "The Chinese Bee-eater". After completion of instruction, the Ss were asked to respond to eighteen open-ended questions about the animal. Eight of the 50 subjects were found to fall into the right hemisphere style of information processing group; fourteen into left; and fourteen into integrated. The remaining fourteen could not be assigned to either of these three categories and were not included in the analysis of the results. the mean scores of the comprehensive test among hemispheric groups and among sex groups. A two way analysis of variance also presented no significant differences among the hemispheric preference combined by sex groups. These results failed to prove the research hypothesis that students who indicate a preference for left hemispheric information processing will have higher scores on a comprehensive test after receiving a didactic mode of instruction, the so-called left style of instruction. Some limits in research process and conceptual confusion about hemisphericity were discussed. Finally, it was suggested that educators need to be more careful in drawing educational implications from neurological hemispheric research.

• Safety and Health at Work
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• v.11 no.2
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• pp.215-221
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• 2020

Background: The aim of this study is to illustrate the historical role of the International Commission on Occupational Health (ICOH) congresses as an arena where national and international occupational medicine can dialogue and as the first example of scientific transferability of the research and prevention results that have had such an impact on global public health. Methods: We used the ICOH Heritage Repository, in which ICOH congress proceedings (from the first congress in Milan in 1906 to the last congress, held in Dublin in 2018), are organised in an orderly way, updated and easily accessible according to open access logic. Results: We describe studies by three physicians who submitted significant scientific work to ICOH congresses, one on the battle against ancylostomiasis (Volante, 1906), the second (Quarelli, 1928) on carbon disulphide poisoning, and the third (Viola, 1969) on the carcinogenicity of vinyl chloride monomer. Priority is given to Italian cases, on account of the authors' obvious familiarity with the issues. Conclusion: The visibility offered in ICOH conferences and their published proceedings has boosted the international spread of their findings, contributing to the scientific transferability of the research results and influencing the development of policies and prevention interventions that have had a great impact on global public health.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.121-128
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• 2017

This paper was to evaluate social enterprises' management efficiency with Data Envelope Analysis (DEA). The data was based on the 168 social enterprises' of annual performance reports published in 2015. The research focused on to measure both financial efficiency and social impact of the companies simultaneously. To apply DEA, the paper classified the enterprises into seven types based on types of socal impacts which each company provides before the estimation of the efficiency. The research results showed that group D, which employes disadvantaged people, provides social services and shares resources was the most efficient group and had higest net worths in Pure Technical Efficiency. In contrast, Group B, which only employs social advantage people and provides social service, was the least efficient one. The research suggests a practical and efficient framework in measuring social enterprises' management efficiency, including both the financial performance and social impacts simultaneously with their self-publishing reports. Because the Korea Social Enterprise Promotion Agency does not open business reports which social enterprises submit each year, there are basic limitations on researchers attempting to analyse with data from all social enterprises in Korea. Thus, this study dealt with only 10% of the social enterprises which self-published their performance report on the Korea Social Enterprise Promotion Agency's web site. Regardless of these limitations, this study suggested substantial methods to estimate management efficiency with the self-published reports. Because self-publishing is increasing each year, it will be the main source of information for researchers in examining and evaluating social enterprises' financial performance or social contribution. The research suggests a practical and efficient framework in measuring social enterprises' management efficiency, including both the financial performance and social impacts simultaneously with their self-publishing reports. The research results suggest not only list of efficient enterprises but also methods of improvement for less efficient enterprises.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.4
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• pp.285-296
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• 2005

In order to reduce the compression power and to use the overall energy contained in LNG effectively, a combined cycle is devised and simulated. The combined cycle is composed of two cycles; one is an open cycle of liquid/solid carbon dioxide production cycle utilizing LNG cold energy in $CO_2$ condenser and the other is a closed cycle gas turbine which supplies power to the $CO_2$ cycle, utilizes LNG cold energy for lowering the compressor inlet temperature, and uses the heating value of LNG at the burner. The power consumed for the $CO_2$ cycle is investigated in terms of a production ratio of solid $CO_2$. The present study shows that much reduction in both $CO_2$ compression power (only $35\%$ of power used in conventional dry ice production cycle) and $CO_2$ condenser pressure could be achieved by utilizing LNG cold energy and that high cycle efficiency ($55.3\%$ at maximum power condition) in the gas turbine could be accomplished with the adoption of compressor inlet cooling and regenerator. Exergy analysis shows that irreversibility in the combined cycle increases linearly as a production ratio of solid $CO_2$ increases and most of the irreversibility occurs in the condenser and the heat exchanger for compressor inlet cooling. Hence, incoming LNG cold energy to the above components should be used more effectively.