• Journal of Energy Engineering
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• v.25 no.1
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• pp.122-130
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• 2016

This study is a numerical study using commercial simulation program GT-Power on 1.5MW diesel engine for power generation. Performance comparison has done for diesel operation with dual fuel operation for different engine load(50%, 75%, 100%) using the target engine model with additional gas injection system. Effect of using Hi-sene, which is actually being used in island area, instead of diesel was also studied. As a result, under 60% natural gas with diesel condition, BSFC was increased by 32% without modifying system. There was almost no change for natural gas/Hi-sene condition compared with natural gas/diesel condition. Decrease of burned fuel fraction was the main reason of these phenomena. After optimizing system, BSFC was improved by 2%.

• Applied Microscopy
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• v.18 no.2
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• pp.177-186
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• 1988

Degeneration of the axon terminals of mamillo-thalamic tract following the electrical coagulation of mamillary body is well known. In this study, the author investigated the ultrastructural alterations of neuropil components, initiated by terminal degenerations. Rats weighing approximately 250 gm were fixed on the stereotaxic instrument(David Kopf Inc., Heavy duty model), and NE 300 active electrode(Rhodes Med. Instr. Inc.) was introduced to the mamillary position of anterior 3.8 mm, lateral 0.5 mm, height 3.8 mm and lateral angle of $23^{\circ}$ according to De Groot's Atlas. Electric current of 20 mA was applied during 1 minute between active and inactive electrodes with Radio Frequency Lesion Generator(RFG 4, Radionics Inc.). Two hours, 2 days, 1 week and 2 weeks following the electrical coagulation of mamillary body, ipsilateral anterior thalamic nucleus was fixed in 1% glutaraldehyde-l% paraformaldehyde and 2% osmium tetroxide, embedded in Araldite mixture, cutted with LKB ultra tome V, stained with uranyl acetate-lead citrate and observed with JEOL 100 CX electron microscope. Observed results were as follows; 1. Degenerated mamillo-thalamic synapses were observed to form asymmetric axospinous or axo-dendritic types. 2. Terminal degeneration was not easily discernible at 2 hours interval after mamillary lesion, but following 2 days the terminal degeneration was apparent. 3. Postsynaptic spines, dendrites and even their cell bodies show edematic changes caused by the degeneration of postsynaptic counterpart. 4. Astrocytic territories, including perivascular processes forming glial limitans of blood-brain barrier, exhibit remarkable expansion. 5. Oligoglia and astroglia are actively engaged in the removal of degenerated elements. 6. Active forms of microglia were increased. 7. The observed results may represent typical ultrastructural alteration pattern within neuropil following the degeneration of certain input axon terminals.

• Korean Journal of Health Education and Promotion
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• v.22 no.2
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• pp.77-95
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• 2005

Objectives: This study measured the extent of local legislators' support for tobacco control policies and identified the predictors of that. Methods: Local legislators, from 21 Gu in Seoul Metropolitan City, underwent a self-administrated questionaire during the 6-week period from December 1, 2004 to January 15, 2005. Multiple linear regression model was used to assess relationships between five groups of variables(political factors including political ideology, personal characteristics, tobacco experiences, tobacco knowledge, contact with local health officers) and support for tobacco control policies based on an 11-item scale. Results: The rates of support for 'penalizing merchants who sell cigarettes to minors' and 'instituting a law mandating that parents should not smoke in a car when children are present' were highest as 87.5% and 82.0% respectively, and those for 'increasing price of cigarettes' and 'regulating stores that sell cigarettes' were lowest as 52.2% and 51.7% respectively. Support was higher among local legislators who thought government had a duty to promote healthy life styles, knew second-hand smoke could cause lung cancer, knew tobacco caused more deaths than alcohol. Support among ex-smokers and nonsmokers was higher than current smokers. Conclusions: The findings indicate that local legislators who oppose tobacco control measures may not be opposed to tobacco control per se, but are more generally opposed to a government role in health promotion, Thus, Tobacco control advocates need to be more attentive to the way tobacco control issues are framed for particular legislators. Further, they could work to increase tobacco knowledge among local legislators.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.210-211
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• 2014

The study was to investigate the effect of the environmental factor on the emotion and satisfaction at the waiting lounge of the international cruise terminal. The results of the study were found as follows: first, the physical environmental factor of the lounge influenced on the positive emotion. Second, the social factor affected the positive emotion. Finally, emotion affected the positive satisfaction. This study suggested that environmental factor was totally affected by emotion and thus environmental management depended on an individual characteristics of the individual place. The port authority will need more efforts to make a better waiting lounge setting for higher tourist satisfaction.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.132-135
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• 2004

In this study, we investigated the effect of threshold on a delivered dose in organ with internal motion by respiration. With mathematic model for 3D dose calculation reported by Lujan et al., we had calculated the position of organ as a function of time in previous study. This result presented that the variation of organ is within 2 mm from initial exhale position to the organ position during operating 1 s. Gating threshold, in this study, is determined to the moving region of target during 1s at a primary position of exhale. This period of gating threshold is 50% of the duty cycle in a half breathing cycle which is period from the top position of exhalation to the bottom position of inhalation. Radiation fields were then delivered under three conditions; 1) existent of moving target in the region of threshold(1sec, 1.5sec), 2) existent of moving target out of the region of threshold, 3) non-moving target. The non-moving target delivery represents a dose different induced due to internal organ motion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.5901-5908
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• 2012

The purpose of this study was to identify construct validity and reliability of instrument for professionalism in physical therapy using developed by American Physical Therapy Association for 470 physical therapists. The corrected data was analysed using confirmatory factor analysis and internal consistency. Model of professionalism was adequate (p<.05) and consisted of 7 factors. Standardized coefficients of construct factor were followed by the integrity (${\beta}$=.93), professional duty (${\beta}$=.92), and compassion/caring (${\beta}$=.86). There were significant difference in professionalism by career(p<.05) but not significant difference by sex(p>.05). Also, the internal consistency for sub-factor of professionalism demonstrated adequate reliability of the measure (Cronbach ${\alpha}$=.80~.96). Because instrument for professionalism in physical therapy have a validity and reliability, it is useful for measuring professionalism in physical therapists.

• Journal of Applied Reliability
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• v.15 no.1
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• pp.44-51
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• 2015

In this study, we propose reliability prediction of a satellite by function analysis. To do so, the intended functions of the satellite are derived from using function structure block diagram, and defined as main, sub, and detailed functions. Furthermore, in order to generate function and reliability structure table, reliability model rule, duty cycle, and types of switch are assigned to the classified functions. This study also establishes reliability block diagram and mathematical reliability models to schematize the relationship among the functions. The reliability of the classified function is estimated by calculating the failure rate of parts comprising them. Finally, we apply the proposed method to a small satellite as a case study. The result shows that the reliability for the detailed function and the sub function as well as the main function could be predicted quantitatively and accurately by the proposed approach.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.602-607
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• 2009

This study is to examine the relation of empowerment and organizational commitment of security practitioners. and it establishes a temporary model that the empowerment of security practitioners effect the organization commitment. for this firstly, it is necessary to understand that their activity of voluntary empowerment is dynamic in any way through security organization. furthermore, all possible efforts of the activity of empowerment must be made for the sustainable self-development. Therefore the development of security organization is dependent upon the improvement of organization commitment through their empowerment.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.231-239
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• 1998

This paper presents the dynamic analysis and control loop design of a zero voltage switching full bridge (ZVS-FB) PWM DC/DC converter. The small-signal model is derived incorporating the effects of phase shift control and the utilization of transformer leakage inductance and power FET junction capacitance to achieve zero voltage resonant switching. These effects are modeled by introducing additional feedforward and feedback terms for duty cycle modulation. Based on the results of the small-signal analysis, the control loop is designed using a simple two-pole one-zero compensation circuit. To show the validity of the design procedures, the small signal analysis of the closed loop system is carried out and the potential of the zero voltage switching and the superiority of the dynamic characteristics are verified through the experiment with a 2 kW prototype converter.

• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.57-68
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• 2016

In this study, we present the modern hybrid system based power generation for electric vehicle applications. We describe the hybrid structure of modified current source based DC - DC converters used to extract the maximum power from Photovoltaic (PV) and Fuel Cell system. Due to reduced dc-link capacitor requirement and higher reliability, the current source inverters (CSI) better compared to the voltage source based inverter. The novel control strategy includes Distributed Maximum Power Point Tracking (DMPPT) for photovoltaic (PV) and fuel cell power generation system. The proposed DC - DC converters have been analyzed in both buck and boost mode of operation under duty cycle 0.5>d, 0.5<d<1 and 0.5<d for capable electric vehicle applications. The proposed topology benefits include one common DC-AC inverter that interposes the generated power to supply the charge for the sharing of load in a system of hybrid supply with photovoltaic panels and fuel cell PEM. An improved control of Direct Torque and Flux Control (DTFC) based induction motor fed by current source converters for electric vehicle.In order to achieve better performance in terms of speed, power and miles per gallon for the expert, to accepting high regenerative braking current as well as persistent high dynamics driving performance is required. A simulation model for the hybrid power generation system based electric vehicle has been developed by using MATLAB/Simulink. The Direct Torque and Flux Control (DTFC) is planned using Xilinx ISE software tool in addition to a Modelsim 6.3 software tool that is used for simulation purposes. The FPGA based pulse generation is used to control the induction motor for electric vehicle applications. FPGA has been implemented, in order to verify the minimal error between the simulation results of MATLAB/Simulink and experimental results.