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A Study On The Characteristic Improvement of 3 Phase Voltage Source PWM Converter (3상 전압형 PWM 컨버터의 특성개선에 관한 연구)

  • Chung, Yon-Tack;Kim, Won-Chul;Chun, Ji-Yong;Kim, Hyun-Woo;Lee, Keun-Hong
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.830-832
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    • 1993
  • In this paper, A voltage source PWM converter which achieves bidirectional power flow between a $3{\phi}$ AC supply and a DC bus voltage is described. And the paper considers both the steady state and transient response of such a device, and develops mathematical models to describe its performance under the digital control system. As a result the AC line current becomes sinusoidal and the input power factor is improved to unity.

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Novel Islanding Detection Method for Distributed Generation Interconnected with Utility Grid (계통연계 분산전원의 새로운 단독운전 판별기법)

  • Lee, Ji-Hern;Jeon, Ji-Hye;Ju, Young-Ah;Han, Byung-Moon
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.2012-2013
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    • 2007
  • 현재 개발된 분산전원 단독운전 판별기법중 하나인 무효전력주입방식은 판별성능은 우수하나 정격의 $2.5{\sim}5%$의 무효전력을 주입하므로 계통전압에 고조파를 발생하여 전력품질을 저하하는 단점을 갖는다. 본 논문에서는 적은 양의 연속적인 무효전력을 주입하므로 전력품질 저하를 최소화하고 동시에 검출성능이 우수한 인버터연계방식 분산전원의 단독운전 판별기법을 개발하였다. 개발한 판별기법의 타당성을 검증하기위해 EMTDC 소프트웨어를 이용하여 전체시스템의 시뮬레이션모델을 개발하여 시뮬레이션을 실시하였다.

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A Case of Occult Foreign Body Lodged in Bronchus for a Long Period and Removal by Flexible Bronchoscopy (굴곡성 기관지 내시경에 의한 장기간 체류한 기관지이물의 제거 1예)

  • Jo, Kyoung-Geun;Baek, Man-Sun;Kim, Mi-Suk;Hur, Jean-Man;Jeon, Jong-Il;Park, Kang-Seo;Jung, Kyung-Tae;Choi, Duck-Yeii;Na, Moon-Jun
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.5
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    • pp.1166-1171
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    • 1997
  • Aspiration of foreign bodies into tracheobronchial tree is more common in children than in adults. Foreign bodies in airway commonly occur by accident, and in most cases they get removed without delay. Small foreign bodies that lodge in the peripheral airway are often asymptomatic initially and can result in respiratory symptoms several years later. Although foreign body aspiration is frequently suspected in children with acute or recurrent pulmonary symptoms, it is rarely considered in adults, unless a clear history of an aspiration event can be obtained. We have experienced and studied a case of occult aspiration of a shrimp which had been lodged for a long period.

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TCP Protocol Performance Evaluation of GMAHN (GMAHN 환경에서의 TCP 프로토콜 성능 분석)

  • Oh, Se-Duk;Kim, Jae-Ho;Bae, Jin-Seung;Jung, Chan-Hyuk;Lee, Chi-Moon;Ha, Jae-Seung;You, Choong-Yeul;Lee, Kwang-Bae;Kim, Hyun-Wook
    • Journal of IKEEE
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    • v.12 no.1
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    • pp.8-17
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    • 2008
  • Recently, GMAHN that provides interface between MANET and Wired Network has been focused in mobile communication. It is necessary that the technology provide reliable data transmission technology between mobile node and wired network in MANET environment that is varied by the node movement. In this paper, using the TCP protocol(Tahoe, Reno, Vegas, SACK)that increases reliability between source and destination, we applied the TCP protocol mechanism to various environment, and proposed the most efficient TCP mechanism by comparing each mechanism.

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A Study on Network Performance Improvement Using Multipath in Global Mobile Ad Hoc Network (Global Mobile Ad Hoc Network에서 다중경로를 이용한 네트워크 성능향상에 관한 연구)

  • Kim, Jae-Ho;Bae, Jin-Seung;Jung, Chan-Hyuk;Lee, Ki-Won;Moon, Tae-Soo;Ha, Jae-Seung;You, Choong-Yeul;Lee, Kwang-Bae;Kim, Hyun-Wook
    • Journal of IKEEE
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    • v.12 no.1
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    • pp.18-26
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    • 2008
  • With the advent of Ubiquitous environment, wired-wireless combination network is being studied very actively in which mobile nodes having multi-hop communication capability connect wired internet network easily, and shares the information. The study of wired and wireless combination network between MANET(Mobile Ad Hoc Network) and wired network is being focused only on the configuration of heterogeneous network interface. The proposed algorithm establishes independent multi-paths between source node and destination node to prevent data loss when errors happen in route. As the result, it shows that the reliability of the combination network can be improved by making data transmit continuously on the route error.

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Plant Growth-promoting Activity of Acremonium strictum MJN1 Isolated from Roots of Panax ginseng

  • Lim, Hyung-Bum;Chung, Yang-Jo;Bae, Ju-Yun;Kim, Dong-Jin;Kwon, Hyung-Jin;Lee, In Hyung;Chung, Byung-Chul;Lee, Woong-Sang;Suh, Joo-Won
    • Journal of Applied Biological Chemistry
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    • v.43 no.2
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    • pp.104-108
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    • 2000
  • The plant growth-promoting activity of Acremonium strictum MJN1 isolated from roots of Panox ginseng was explored. The myceliaI extract of A. strictum MJN1 enhanced the rice seedling growth by 14.5 and 9.0% in the dried weight of shoots and roots, and the growth of red pepper by 54 and 85% in the top length and the dried weight in pot experiments, respectively. The plant growth-promoting substances in the myceliaI extract of Acremonium strictum MJN1 were identified as D-adenosine and glycerol. Both commercial D-adenosine and glycerol also promoted significantly the rice seedling growth but, unlike the mycelial extract of A. strictum MJN1, hardly affected the yields of plants grown in pots or field. Therefore, it is possible that other plant growth-promoting substances are produced by A. strictum MJN1. However, this study shows that A. strictum MJN1 has a great potential as a biofertilizer.

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The Comparison of Effectiveness between Acupuncture and Its Cotreatment with Direct moxibustion to Low back pain patient (요통(腰痛) 환자에 대한 침치료(針治療)와 직접구(直接灸) 병행치료(竝行治療)에 대한 비교(比較) 연구(硏究))

  • We, Jong-sung;Won, Seung-hwan;Hwang, Jung-soo;Sun, Seung-ho;Ahn, Young-min;Sohn, Seung-hyun;Park, Ki-chul;Park, Hee-soo
    • Journal of Acupuncture Research
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    • v.21 no.6
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    • pp.221-231
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    • 2004
  • Objective : The purpose of this report is to examine the effects of direct moxibustion in the Low back pain patient. Methods : Clinical studies were done 30 patients who were treated with low back pain to Dept. of Acupuncture & Moxibustion, of Oriental Medical Sang-Ji University from September 1, 2003 to August 31, 2004. We treated them by Oriental medical therapy(including direct moxibustion)for 10 days. The evaluation was performed five times(admission day, before and after each twice). Results : 1. VAS was decreased after direct moxibustion for 10 days significantly(p<0.01). 2. After direct moxibustion, S.L.R. T angle of patients were increased. ConclUsions : We brought to the conclusion that direct moxibustion has possibility to the efficient to cure the Low back pain. So we suggest the possibility to use this treatment for Low back pain.

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