야생 흰 제비꽃(viola patrinii DC.)callus의 현탁배양 방법이 세포 활성에 미치는 영향

김두현,정용모,정정한,이인,권오창,Kim, Du-Hyun,Chung, Yong-Mo,Chung, Chung-Han,Yeeh, Yeehn,Kwon, Oh-Chang 한국생명과학회 1996 생명과학회지 Vol.6 No.2

To understand effect of inoculum size, cell density, sucrose concentration and concentrations of MS basal on suspension culture and protoplast isolation of wild viola(Viola patrinii DC.) callus from petiole segments this experiment was conducted. In the lot of 30 mesh inoculum size, two observations were; One was that a considerable increase in the fresh and dry weight of callus was determined. Another was that the callus mass was relatively compact compared with others. A recommendable cell density was 0.4g for 20ml culture medium and the higher sucrose concentration, the higher fresh and dry weight were obtained. The dilution of MS basal salt was differently affected on fresh and dry weight; the highest fresh weight was found in 1x MS salt, while the higest dry weight was in 1/3x dilution.The addition of casein hydrolysate(3g/L) was more effective to increase of both fresh and dry weight. THe contents of protein was great in the inoculum lots with larger inoculum sizeand higher concentration of MS basal salts contenting 3g/L of casein hydrolysate and higher sucrose compared with others. The greatest protoplasts were isolated from the lot of 10 mesh size treated with 1%pectinase SE-150 and 2% cellulase YC. In general, for optimal protoplast isolation the followingconditions were recommended; 1) Use of smaller cell size cultured for 2-5 weeks, and 2) more than 5 hours incubation using the combined mixture of the enzymes with proper concentrations.

존덕정

김두현,Kim, Du-Hyeon 대한건축사협회 1984 建築士 Vol.1984 No.4

멀티미디어 I/O 인터페이스의 역활

김두현,김명관,백순철,오승준,오병주,Kim, Du-Hyeon,Kim, Meong-Kwan,Baek, Sun-Chul,Oh, Seong-Jun,Oh, Byeng-Jun 한국전자통신연구원 1990 전자통신동향분석 Vol.5 No.1

지능형컴퓨터 개발과제에서 사용자 인터페이스 역할을 담당할 지능형컴퓨터의 멀티미디어 사용자 인터페이스의 역할에 대하여 논한다. 먼저 인간과 컴퓨터와의 정보교환시에 일어나는 인지적현상을 밝히고 이에 근거하여 멀티미디어 사용자 인터페이스를 설계할때의 3원리(Multimedia Dialogue, Interface Transparency, Interface Independancy)를 제안한다. 그리고 제안된 원리에 맞는 지능형 컴퓨터시스템 상에서 멀티미디어 사용자 인터페이스의 위치와 요소를 밝히고, 이들이 사용자에게 제공해야 할 외향적 기능과, 지능형운영체제에 제공해야할 내향적 기능을 열거한다.

가전 유통시장 개방과 우리의 대응

김두현,Kim, Du-Hyeon 한국전자정보통신산업진흥회 1996 電子振興 Vol.16 No.6

지상과 수중에서의 전격 위험성 평가

김두현,강동규,Kim, Du-Hyeon,Gang, Dong-Gyu 대한산업안전협회 2004 안전기술 Vol.80 No.-

유도가열시스템의 구성부품에 대한 강건설계

김두현,김성철,이종호,강문수,정천기,Kim, Doo Hyun,Kim, Sung Chul,Lee, Jong Ho,Kang, Moon Soo,Jeong, Cheon Kee 한국안전학회 2021 한국안전학회지 Vol.36 No.2

This paper presents the robust design of each component used in the development of an induction bolt heating system for dismantling the high-temperature high-pressure casing heating bolts of turbines in power plants. The induction bolt heating system comprises seven assemblies, namely AC breaker, AC filter, inverter, transformer, work coil, cable, and CT/PT. For each of these assemblies, the various failure modes are identified by the failure mode and effects analysis (FMEA) method, and the causes and effects of these failure modes are presented. In addition, the risk priority numbers are deduced for the individual parts. To ensure robust design, the insulated-gate bipolar transistor (IGBT), switched-mode power supply (SMPS), C/T (adjusting current), capacitor, and coupling are selected. The IGBT is changed to a field-effect transistor (FET) to enhance the voltage applied to the induction heating system, and a dual-safety device is added to the SMPS. For C/T (adjusting current), the turns ratio is adjusted to ensure an appropriate amount of induced current. The capacitor is replaced by a product with heat resistance and durability; further, coupling with a water-resistant structure is improved such that the connecting parts are not easily destroyed. The ground connection is chosen for management priority.

효율적인 고출력 LED 디밍 제어를 위한 회로 설계 및 구현

김두현,최재호,조범준,Kim, Doo-Hyun,Choi, Jae-Ho,Cho, Beom-Joon 한국정보통신학회 2014 한국정보통신학회논문지 Vol.18 No.9

기존의 고출력 LED의 디밍(Dimming) 제어 방법에는 펄스폭변조, 주파수변조, 아날로그 제어 방법이 있으며, 아날로그 디밍은 순방향 고출력 LED 전류를 조정하는 방법으로 0%~100%의 전 범위에서 선형 밝기 조절이 가능하나 순방향 전류를 변화시킴으로써 파장의 변화가 존재하고, 펄스폭변조 디밍 제어는 고출력 LED에 흐르는 정격 전류의 듀티를 가변하여 조도를 제어하는 방식으로 저 레벨(0%~10%)에서 선형 밝기 조정이 어렵다. 그리고 주파수변조 디밍 또한 저 레벨의 디밍에서 빛이 깜박거리는 문제를 내포하고 있다. 본 논문은 이러한 디밍 방식의 단점을 보완하고자 저 레벨 디밍 제어 시 아날로그 방식을 적용하고, 10%~100%의 디밍 제어 시에 펄스폭변조 방식을 적용하는 효율적인 디밍 제어 회로의 설계 및 구현을 제안한다. 전 범위에 걸쳐 선형 밝기 조절이 가능하고, 다양한 디밍 레벨에서 일정한 파장의 출력이 가능한 디밍 제어 회로를 구현하였으며, 실험 결과는 제안한 방법의 우수성을 보여주고 있다. The conventional dimming control methods of LED (Light-emitting dioades) include Analog, PWM (Pulse Width Modulation), and FM (Frequency Modulation) Control. Analog dimming is controlled by adjusting forward current of Power LED. Although Analog dimming is possible to control linearly the brightness levels on a whole range (0%~100%), it comes into existence a variation of wavelength by changing the Power LED's forward current. PWM dimming has achieved by varying in duty of full current flowing to the Power LED. Generally, PWM dimming doesn't make variation of wavelength but have difficulty with adjusting the linear brightness level between 0% and 10%. FM dimming method is on the same wavelength as PWM dimming, however, it has problem of flickering at low level of dimming. This paper propose a efficient dimming control method of Power LED in order to overcome the disadvantages of the above mentioned methods. We apply to Analog method in low level of dimming control and use PWM method in dimming range from 10% to 100%. For the experiment, we design and implement a circuit and test the proposed method. Consequently, we can control the linear brightness of Power LED across the whole range and get the constant wave at different dimming level. The experimental results show the benefits of the proposed method.

An Object-Oriented, Client-Server Architecture for a Generalized Multimedia a Processing Model in a Distributed Multimedia System

김두현,임영환,Kim, Doo-Hyun,Lim, Young-Hwan 한국정보처리학회 1996 정보처리학회논문지 Vol.3 No.1

본고는 분산 멀티미디어 시스템 환경에서 여러가지 응용 서비스를 지원하기 위한 범용 멀티미디어 데이타 처리 모델을 제시하고 그것을 구현하기 위한 객체지 향, 클 라이언트 서버 구조에 대하여 기술하였다. 이 모델은 분산 멀티미디어 시스템에서 필 요한 원격 데이타의 이용을 위한 통신망 투명성과 실시간 멀티미디어 입출력, 그리고 미디어의 통합이나 동기화 등의 멀티미디어 처리를 지원하는 범용 모델이다. 이 모델 은, 스트립 계층, 멀티미디어 프리젠테이션 계층, 하이퍼 프리젠테이션 계층등으로 구 성된다. 본 고는 이 모델의 각 계층에 해당되는 추상적인 데이타개념을 정의하고 이것 이 각 계층의 서비스와 실재로 객체지향 기법으로 제공되는 AP(Application Programming Interface)가 어떻게 연결되는지 기술하였다. 그리고 실제 구현하기 위한 구체적인 문제 를 예를 들면서 다루었고 마지막에 추후 연구해야 할 방향을 제시하며 결론을 맺었다. In this paper, we describe a multimedia data processing model that supports wide variety of applications based on multimedia production model. This model supports network-transparent access to stored multimedia data, real-time mult media input devices, and multimedia processing. The model addresses real-time dato a switching and delivery, as well as acquisition, processing, and output. Most translation, compression, and synchronization services are integrated. This model consists of three layers: (1) stream, (2) multimedia presentation, (3) hyperpresentaion. This paper describes the data abstractions associated with each layer. These data abstractions provide a framework for defining the services provided by each layer, and describe the object-oriented mechanisms that provide those services. A sample scenario is presentated to illustrate the use of this model. A server-client architecture and implementation issues, and future directions are also discussed. sed.

FTA를 이용한 볼트 유도가열시스템의 고장 및 전기화재 분석

김두현,김성철,엄한얼,강문수,정천기,Kim, Doo-Hyun,Kim, Sung-Chul,Eom, Haneol,Kang, Moon-Soo,Jeong, Cheon-Kee 한국안전학회 2021 한국안전학회지 Vol.36 No.4

This paper presents a safety assessment method for FTA-based induction heating systems; the failures and causes of electrical fire are first analyzed for each part and module qualitatively, and methods to manage high probabilities of failure and electrical fire are considered, thereby improving the reliability of the induction heating system. The cumulative importance value (ACC) of the minimal cut set is drawn by setting failure as the top event, and STACK and SMPS are observed to account for about 70% of the induction heating system failures. Thus, intensively managing the basic events contained in the minimal cut set of failures for STACK and SMPS is expected to provide effective and stable operation of the induction heating system. When electrical fire is set as the top event, the STACK percentage is 90%. Accordingly, the current IGBT is changed to a FET to increase the applied voltage and prevent induction heating system failure, and a heat sink plane is installed to prevent FET heating caused by switching, thereby preventing an electrical fire. By classifying the parts and modules of the induction heating system in detail and by applying FTA based on actual failure rates and relevant data, more practical and reasonable results may be expected. Hence, continuous research must be conducted to ensure safety when using induction heating systems.

멀티미디어 산업의 구조전망 및 기업의 M&A

김두현,Kim, Du-Hyeon 한국전자정보통신산업진흥회 1997 電子振興 Vol.17 No.5