• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.61-67
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• 2000

In switched reluctance motor(SRM) drive, it is necessary to synchronize the stator phase excitation with the rotor position. Therefore the rotor position information is an essential. Usually optical encoders or resolvers are used to provide the rotor position information. These sensors are expensive and are not suitable for high speed operation. In general, the accuracy of the switching angle is dependent upon the resolution of the encoder and the sampling period of the microprocessor. But the region of high speed, switching angles are fluctuated back and forth from the preset values, which are cause by the sampling period of the microprocessor. Therefore, the low cost linear encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper. It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.319-326
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• 2002

In switched reluctance motor(SRM) drive, it is important to synchronize the stator phase excitation with the rotor position; therefore, the information about rotor position is essential. Generally, optical encoders or resolvers are used to provide the information. However, these sensors are expensive and are not suitable for high-speed operation. The accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor. In the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost linear encoder suitable far the practical and stable SRM drive is proposed and also the control algorithm to generate the switching signals using a simple digital logic is presented. The validity of the proposed linear encoder with a proper logic controller is verified through the experiments.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.1
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• pp.18-25
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• 2005

We have researched 10,811 schools to evaluate the characteristics of school buildings and the conditions of heating and cooling systems at the elementary, middle and high school levels. Air conditioning systems in school buildings are related to school scale, and 35% of the researched schools have less than 10 air conditioned classrooms among all of the schools in Korea. The LOADSYS is used to grasp the characteristics of school buildings heating and cooling load. From the results of this work, the heating load differs by nearly 24% between Seoul and Busan, but other than that there are not so many serious regional differences. Almost 85.4% of the classrooms are equipped with heating facilities and 6.9% of them are equipped with heating and cooling facilities. As a result, it is necessary to make improvements in 31.8% of the classrooms using only heaters and 14.6% of the classrooms not equipped with HVAC. The survey shows that there is a wide gap in the heating equipment status of the classrooms according to the region and school district.

• Journal of Environmental Science International
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• v.20 no.8
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• pp.1049-1059
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• 2011

This paper examines the effects of the partial solar eclipse of 22 July 2009 across the Korean peninsular on surface temperature and ozone concentrations in over the Busan metropolitan region (BMR). The observed data in the BMR demonstrated that the solar eclipse phenomenon clearly affects the surface ozone concentration as well as the air temperature. The decrease in temperature ranging from 1.2 to $5.4^{\circ}C$ was observed at 11 meteorological sites during the eclipse as a consequence of the solar radiation decrease. A large temperature drop exceeding $4^{\circ}C$ was observed at most area (8 sites) of the BMR. Significant ozone drop (18~29 ppb) was also observed during the eclipse mainly due to the decreased efficiency of the photochemical ozone formation. The ozone concentration started to decrease at approximately 1 to 2 hours after the event and reached its minimum value for a half hour to 2 hours after maximum eclipse. The rate of ozone fall ranged between 0.18 and 0.49 ppb/min. The comparison between ozone measurements and the expected values derived from the fitted curve analysis showed that the maximum drop in ozone concentrations occurred at noon or 1 PM and was pronounced at industrial areas.

• Archives of Craniofacial Surgery
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• v.19 no.1
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• pp.64-67
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• 2018

Varying degrees of complications can occur after hyaluronic acid filler injections. Tissue necrosis due to interruption of the vascular supply is an early complication that can be severe. If the site of tissue necrosis due to the filler injection is the forehead, successfully reconstructing the region without distorting the key landmarks is challenging. We describe the case of a 50-year-old man who experienced widespread forehead skin necrosis after hyaluronic acid filler injection in the glabellar area. We successfully covered the forehead area with a $3{\times}4-cm^2$ midline necrotic tissue using the modified double-opposing rotation-advancement flap method. Although modified double-opposing rotation-advancement flap closure has the disadvantage of leaving a longer scar compared to conventional double-opposing rotation-advancement flap closure, the additional incision line made along the superior border of the eyebrow aids in camouflaging the scar and decreases eyebrow distortion. Therefore, it is believed that the modified double-opposing rotation-advancement flap technique is an excellent tool for providing adequate soft tissue coverage and minimal free margin distortion when reconstructing widespread skin necrosis in the central mid-lower forehead that can occur after filler injection in the glabellar area.

• Korean Journal of Human Ecology
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• v.15 no.2
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• pp.341-352
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• 2006

This study examined health-functional foods intake pattern of consumers and their recognition of it to prepare a guide for the foods. The data were collected from the adults living in Busan and Gyeongnam through a self-administered questionnaire from September sixth to September thirteenth, 2005. The results of this study were as follows: Most respondents have taken one health-functional food, mainly on purpose to maintain and improve overall health condition. The average of monthly cost to purchase the foods was 79,933 Korean won, and drugstores were the main purchasing place. The value perception about health-functional foods was at the middle, and the recognition level of Health Functional Foods Act established in 2002 was very low. The most important source of information regarding health-functional foods was family, relatives and friends, and two-fifths respondents had difficulties in obtaining information. These results imply that consumers should consult with experts before they take health-functional foods and that public information regarding Health Functional Foods Act should be given to consumers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.1
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• pp.189-205
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• 1996

The twin-roll type strip continuous casting process(or direct rolling process) of steel materials is characterized by two rotating water cooled rolls receiving a steady supply of molten metal which solidifies onto the rolls. A solidification analysis of molten metal considering phase transformation and thermofluid is performed using finite diffefence method with curvilinear coordinate to reduce computing time and molten region analysis with arbitrary shape. An enthalpy-specific heat method is used to determine the temperatures inthe roll and the steel. The temperature distribution of cooling roll is calculated using two dimensional finite element method, because of complex roll shape due to cooling hole in rolls and improvemnt accuracy of calculation result. The energy equaiton of cooling roll is solved simultanuously with the conservation equaiton of molten metal in order to consider heat transfer through the cooling roll. The calculated roll temperature is compared to experimental results and the heat transfer coefficient between cooling roll surface and rolling material(steel) is also determined from comparison of measured roll temperature and calculated temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.447-452
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• 2017

In this study, we tried to identify a sea anemone collected from the coast of Gijang, Busan. The anemone was morphologically similar to species belonging to the genus Anthopleura, but its morphological characteristics did not allow for confirmed identification to species level. Multiple genes from mitochondrial cytochrome oxidase III, 12S and 16S rRNA, and nuclear 18S and 28S rRNA, were amplified for multilocus sequence typing (MLST) analysis using genomic DNA extracted from the sampled anemone and a different primer set. Based on the MLST analysis, the anemone obtained in this study was identified as Anthopleura artemisia. Also, the sequence of internal transcribed spacer-2 was most closely related to A. artemisia, indicating that this single region might be useful for anemone identification. This study shows significance of molecular identification for sea anemones, and will be helpful in studies of sea anemone identification using genotyping-by-sequencing.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.107-112
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• 2010

Wind power generation is the natural source energy without pollution, and the highest economic efficiency among renewable energies. Amid the recent development of small wind power generation, wind power generation facilities can be installed in the super high-rise buildings or complexes. It is necessary to conduct analyses on appropriate locations in a bid to promote efficient power generation in those locations. In this study, relative weight of the elements required for the wind power generation were estimated by using the Analytic Hierarchy Process in Busan City, and the characteristics of wind velocity and wind direction in Busan City were expressed. As a result, 'Dadae 1-dong, Cheolma-myeon, Noksan-dong' was selected as the candidate region inside Gangseo-gu, Gijang-gun, Saha-gu by using the geo-spatial information system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.622-626
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• 2010

Cu doped $SnO_2$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and annealed at $500^{\circ}C$ in air, respectively. Structural properties of $SnO_2$ by X-ray diffraction showed (110), (101) and (211) dominant tetragonal phase. The effects of catalyst Cu in $SnO_2$-based gas sensors were investigated. Sensitivity of $SnO_2$:Cu sensors to 2,000 ppm $CO_2$ gas and 50 ppm $H_2S$ gas was investigated for various Cu concentration. The highest sensitivity to $CO_2$ gas and $H_2S$ gas of Cu doped $SnO_2$ gas sensors was observed at the 8 wt% and 12 wt% Cu concentration, respectively. The improved sensitivity in the Cu doped $SnO_2$ gas sensors was explained by decrease of electron depletion region in Cu and $SnO_2$ junction, and increase of reactive oxygen and surface area in the $SnO_2$.