• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.401-408
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• 2019

This study was conducted to analyze the industrial concentration of the districts, cities and counties among clinics, dental clinics, and Oriental clinics. For this purpose, the sales from 1996 to 2015 in five-year intervals were analyzed by the Heifindal-Hirschmann index (HHI). The results of this study showed that the competition index represented by the HHI tended to intensify as a whole. Especially in the county area, HHI tended to be in comparison with other regions, but decreased with statistically significance. On average, the HHI was higher in the county than in the district and city areas. In the case of the clinic, the HHI of the county area tended to decrease. In the case of the dental clinic, the HHI tended to decrease in the city and county, while in the Oriental clinic the HHI tended to decrease in the district, city and county. Overall, monopolies were present in the county, but competition strengthened over time. In the case of clinics, competition is intensifying in country. area. In the case of dental clinics, competition in the city and country areas has not yet reached saturation. In the case of Oriental clinics, competition in all regions has not yet been saturated, and competition in the distinct market has been most intense.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.352-355
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• 2001

This paper makes a general description of the results at government project which were peformed for several years. Through this project, the real capacity of 3.3KV/4MW Class 3 Level Voltage Source Inverter System were designed and the characteristics of its proto type were analyzed, moreover the web based IIMS(Inverter Information Management System) and Virtual Operation Simulator was developed. Now, this system is running for field application test.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1227-1230
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• 2007

This paper describes recent advances in the R&D work achieved at Fraunhofer HHI (Germany) that are believed to provide key technologies for the development of future human-machine interfaces. The paper focus on the area of vision based interaction technologies that will be one essential component in future three-dimensional display systems.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.83-84
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• 2007

본 논문은 변압기 소음저감을 위하여 Active part와 외함 형상변경에 따른 연구를 수행하였다. Active part는 변압기 소음의 주 원인인 철심의 적층방법 및 적층 step수에 대해 분석하였으며, 외함의 형상을 원형으로 변경하고 충격시험 및 유한요소 해석을 통해 원형외함의 특성을 파악하였다.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.308-310
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• 1995

Most of the elevator door controllers have been controlled by DC Motors as an actuator. Recently, The control system using AC induction motor and general purpose inverter has been applied to control of elevator door. But there are some difficulties in making use of this system, such as adjustment of door speed pattern, door open-close time, and security of passenger safety. In order to solve these problems, a special inverter has, been developed with an encoder feedback. From the result of field-test, we proved that a special inverter with encoder feedback device has come to considerable effect. Until now about 1,200 sets of these inverters are operated in Korea and about 100 sets are operated in South-east Asia.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.3
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• pp.139-143
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• 2005

Several methods have been proposed to mitigate the market power in foreign electricity markets. In this paper, Hirfindahl-Hirschman Index(HHI) and supply margin assessment(SMA) are compared based upon the Korean future markets. The results show that SMA is better than HHI to estimate market power because it can reflect congestion and capacity reserve effectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.38-42
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• 2003

The use of VPI impregnated mica tape as high voltage insulation for large rotating electric machines requires a careful balance of processes and materials to obtain the desired electrical, mechanical and thermal characteristics. The stator insulation systems such as epoxy bonded high voltage mica tape have been produced for many years. One such system employing an epoxy and anhydride impregnating resin developed by Hyundai Heavy Industries, Co. (hereafter, HHI), to satisfy customer requests for an epoxy bonded insulation system. HHI applies the following electrical and thermal evaluations such as dielectric breakdown, voltage endurance, dissipation factor vs. temperature, isothermal weight loss, and so on. A detailed laboratory evaluation can describe specific physical limitations for an insulation system and permit development of long-term operation guidelines that permit full utilization of the proposed system. HHI has found these evaluations very helpful in qualifying insulation system for the repair of both large motors and generators.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.1
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• pp.73-79
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• 2017

It is difficult to detect the adult hearing loss after the language acquisition because of its slow progression, which can be evaluated voluntarily and actively when the appropriate tools are provided. Smartphones are one of useful tools, and they can utilize surveys and/or applications for hearing screening. This study aims to verify the possibility as a tool discovering delayed acquired hearing losses by comparing the pure tone screening application (app_PTS) which was recently developed by our research team and hearing handciap inventory (HHI). The subjects were 22 people whose age ranges from 10s to 80s. For pure tone averages (PTAs), hearing threshold level was selected the best one in same frequency, in both ears. Sensitivity and specificity of HHI were confirmed based on self awareness of hearing loss and PTAs at 1, 2, 4 kHz. Comparisons of two tests were measured by analyzing simple regression of correlation between PTAs of App_PTS and HHI scores. Sensitivity and specificity were 1.000 in both criteria. There was a statistically significant relationship between the PTAs_4 kHz and HHI (R-square = .951, p = .000). Hearing screening by questionnaire showed high correlation with smart phones based on application. Therefore, it can be useful as a hearing screening tool for individual life cycle using an user-friendly tool.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.338-344
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• 2021

Elements that threaten domestic security, such as diplomatic changes in the four major powers surrounding the Korean Peninsula and restrictions on supply and demand of parts due to COVID-19, are constantly increasing. The importance of localizing weapon systems has grown to respond proactively to the threat. As localization is not conducted evenly by the field, it is necessary to change the criteria for selecting localization targets. Establishing standards for selecting targets is difficult due to a lack of research to identify targets. This paper emphasized that the smooth supply of parts from overseas should be examined to identify targets for localization. If suppliers are not distributed evenly in the market, there is a risk of potential supply problems. CRk and HHI, representing the market structure, were proposed as indicators for evaluating the degree of smoothness quantitatively. Among them, CRk is used in Korea to check the market concentration, but there is a limit in the subjectivity of the evaluator, so it cannot be applied without a separate study on the market structure. Therefore, HHI should be applied.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1337-1339
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• 2001

We have investigated the relation between the molecular weight distribution (MWD) of diffusible species and the recovery rate of hydrophobicity of room-temperature vulcanizing (RTV) silicone rubber (SIR) using solvent extraction at various temperatures. It was observed that the extract had a MWD ranging from a few hundreds g/mol to hundreds of thousands g/mol. By measuring the migration of siloxane to the extracted SIR surface through a thin carbon coating, the aspect of migration of diffusible species was observed as a real time plot, and the time constant of the migration was also calculated. According to the time dependence of IR-absorbance, the time constant was increased with the increase of MW of the extracts.