• Journal of Power Electronics
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• 제17권2호
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• pp.522-532
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• 2017

This paper presents a novel integrated structure for a cascaded distribution static compensator (D-STATCOM) and distribution transformer for medium-voltage reactive power compensation. The cascaded multilevel converter is connected to a system via a group of special designed taps on the primary windings of the Dyn11 connection distribution transformer. The three-phase winding taps are symmetrically arranged and the connection point voltage can be decreased to half of the line-to-line voltage at most. Thus, the voltage stress for the D-STATCOM is reduced and a compromise between the voltage rating and the current rating can be achieved. The spare capacity of the distribution transformer can also be fully used. The working mechanism is explained in detail and a modified control strategy is proposed for reactive power compensation. Finally, both simulation and scaled-down prototype experimental results are provided to verify the feasibility and effectiveness of the proposed connection structure and control strategy.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8243-8248
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• 2015

본 연구의 목적은 유아교육 현장에서 원장이 갖춰야 할 것이 무엇인지 알아보고자 하였다. 이를 위하여 어린이집에서 종사하는 10년 이상의 경력을 지닌 원장 10명을 연구 참여자로 선정하여 그들이 교육현장에서 경험하고 탐구한 원장으로서의 필요한 자질과 역할, 태도와 이미지에는 어떤 것이 있는지 알아보고, 그것이 교사들에게 어떤 영향을 미치는지 밝혀내고자 토론과 심층면담을 실시하였다. 본 연구의 결과는 다음과 같다. 첫째, 유아교육현장에서 요구하는 원장의 자질은 전문가적 자질이나 지도자적 자질보다 인성적 자질이 우선적으로 요구되었다. 둘째, 교사의 역량을 키우고, 교육을 활성화시키는데, 교육에 대한 책임감 있는 자세와 전문가적인 태도는 원장이 갖춰야 할 중요한 요소로 요구되었다. 셋째, 원장의 이미지는 교사의 의사결정과 교육에 영향을 주는 것으로 나타났다.

• 대한추나의학회지
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• 제3권1호
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• pp.125-139
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• 2002

Objectives : The purpose of this study is to review and summarize about occupational medicine and to applicate the occupational medicine to oriental medicine. Methods : We investigated several books, articles and related internet sites to know occupational medicine's present conditions in Korea and other countries, and researched the plan on oriental medical participation in the industrial health. Results and Conclusion : The conclusions are as follows, 1. Recent years, industrialization has changed working environment and health condition in workplace, so industrial health service has became important part. 2. Occupational medicine has the purpose of protection. prevention, fitness, health management, medical treatment. rehabilitation, and primary medical service. The range of occupational medicine is enlarged mental, social good health and social, economical production capacity recently. 3. After research each country's occupational medicine, we can know the purpose is same, but the system and work contents are different one another. 4. Oriental medical participation in the industrial health has various benefits, satisfaction of workers, efficiency of cost, and increasing rate of medical treatment through the western and oriental medical cooperation.

• 대한기계학회논문집
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• 제15권1호
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• pp.349-354
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• 1991

본 연구에서는 이에 대한 열역학적 기초연구로서, 그러한 시스템을 단순화하 여 주어진 온도의 두 무한열원 사이에 두개의 카르노 사이클이 존재하는 이중돌력 사 이클에 대하여, 최대출력조건에서의 사이클의 온도와 각 열교환기의 용량 등을 구하였 다. 또한 사이클이 가역이 아닌 경우 사이클의 가역도에 따른 최대 출력 조건의 변 화 등도 검토하였다.

• 한국지열·수열에너지학회논문집
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• 제5권1호
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• pp.7-11
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• 2009

The purpose of this study is to investigate the performance of a water heat source cascade heat pump system R717(Ammonia) is used for a low-stage working fluid while R134a is for a high-stage. In order to gain a high temperature supply water in winter season, the system is designed to perform a cascade cycle. In this study, two experiments were carried out. One is a system starting test from the low load temperature of $10^{\circ}C$. The other is a system performance investigation over the R717 compressor capacity changes. Experimental results show that when it starts from the low load temperature, the suction temperature of the low-stage compressor is higher than that of a high-stage. The system performance increases when a water source temperature or a low-stage compressor rotational frequency goes higher.

• 한국연초학회지
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• 제35권1호
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• pp.56-61
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• 2013

Bryonia alba L. belongs to the Cucurbitaceae family and grows in Europe, Asia, America, Africa, Russia, Ukraina and Armenia. The root of Bryonia alba has been used for neuropsychical diseases, psychosis, hysteria, paralysis, epilepsy, vertigo, headache, migrain, melancholia, forgetfulness, sadness, absent mindedness, delirium, cardiovascular disease, ischemia, gastrointestinal diseases, gastric ulcer and respiratory diseases. The root of Bryonia alba contains an oxidized tetra cyclic triterpens, cucurbitaceous, polyunsaturated hydrocarbons, phospholipids, phosphatidylcholines, ethereal oils, fatty acids, a great amount of amino acids, alcohol soluble enzymes, sugar, carotene, vitamin C and E. Bryonia alba increases coronary blood-flow and the amplitude of cardiac contractions. Bryonia alba has an antistressor action and increases the working capacity. Bryonia alba activates connective tissue cells. Bryonia alba markedly increases the oxygen consumption by young and senescent rat brain, liver as well as heart mitochondrial fraction as Korean Ginseng. Bryonia alba decreases lipid peroxidation after immobilization stress. In conclusion, Bryonia alba like Ginseng used in traditional medicine came from ancient time has a good perspective administration as prophylactic and medical remedy, as remedy of lot of diseases in modern medicine.

• 대한안전경영과학회지
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• 제9권3호
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• pp.95-102
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• 2007

Nowadays, globally high-grade companies have done their best for increasing their competitive power through a many kinds of method in incisive competition for making certain of a pacesetting position. Among the rest, Six Sigma have been the best methodology of improving process and have proven to be effective by the result of improving process in many of manufacturing business, however, it has not obtained excellent results in the transaction business. In transaction business, a $30\sim50%$ costs in total costs is generated by slow-speed working and reworking. The slow processes decrease the quality and increase the cost, which decreases customer satisfaction, and finally the income is decreased. All of them are so called wastes in processes. For this, adopting of lean six sigma methodology in process management can eliminate the wastes and reduce the variation. This study focuses on distribution with the domains like capacity, layout, amount of location, assignment of product, operation procedure and operation rule in order to improve these domains, we make a further application of eight analysis ways based on DMAIC method for improving operation of processes of distribution center as the third profit source. The goal of this study is to trace an approach that can easily adopt of Lean Six Sigma in operational management of distribution center by a kind of data, analysis method and template.

• Journal of Information Processing Systems
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• 제2권2호
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• pp.101-106
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• 2006

Grid computing is an emerging technology that enables global resource sharing. In Korea, the $K^*$Grid provides an extremely powerful research environment to both industries and academia. As part of the $K^*$Grid project, we have constructed, together with the Korea Institute of Science and Technology Information and a number of domestic universities, a supercomputer Grid test bed which connects several types of supercomputers based on the globus toolkit. To achieve efficient networking in this Grid testbed, we propose a novel method of available bandwidth measurement, called Decoupled Capacity measurement with Initial Gap (DCIG), using packet trains. DCIG can improve the network efficiency by selecting the best path among several candidates. Simulation results show that DCIG outperforms previous work in terms of accuracy and the required measurement time. We also define a new XML schema for DCIG request/response based on the schema defined by the Global Grid Forum (GGF) Network Measurement Working Group (NM-WG).

• 한국정밀공학회지
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• 제31권10호
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• pp.913-922
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• 2014

This paper describes design of a robotic above-knee prosthetic leg which is powered by electrical motors. As a special feature, the robotic prosthetic leg has enough D.O.F.s. For mimicking the human leg, the robotic prosthetic leg is composed of five joints. Three of them are called 'active joint' which is driven by electrical motors. They are placed at the knee-pitch-axis, the ankle-pitch-axis, and the an! kle-roll-axis. Every 'active joint' has enough torque capacity to overcome ground reaction forces for walking and is backlashless for accurate motion generation and high-performance balance control. Other two joints are called 'passive joint' which is activating by torsion spring. They are placed at the toe part and designed by Crank-rocker mechanism using kinematic design approach. In order to verify working performance of the robotic prosthetic leg, we designed a gait trajectory through motion capture technique and experimentally applied it to the robot.

• 한국전산유체공학회지
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• 제16권1호
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• pp.67-72
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• 2011

HRSG (Heat Recovery Steam Generator) is a boiler to recover heat from the exhaust gas of an engine and to generate steam for more power generation or process. For the HRSG, water-tube type boiler is commonly adopted to accommodate the working pressure or capacity requirement of the system. The water-tube type boiler has a steam drum to separate steam from the water-steam mixture supplied from the evaporator tube (riser). The drum should be sized properly to separate the steam by the gravity and auxiliary internals, such as a demister, which are installed to filter the steam. To size the steam drum and to estimate the filter efficiency of drum internals, the velocity distribution inside the drum needs to be identified. In the present study, a series of CFD has been conducted to find the velocity distributions inside steam drums for conventional HRSGs and water-tube type industrial boilers. The velocity distributions obtained from the simulation have been normalized and a correlation to predict them has been found. The correlation is applied to the steam drum design by determining a proper position of a demister to show proper separation performance.