• Title/Summary/Keyword: Hold-up

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Survey on the status of integrated science education in middle school (통합과학교육의 실태조사)

  • Lee, Hack-Dong
    • Journal of The Korean Association For Science Education
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    • v.6 no.2
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    • pp.43-52
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    • 1986
  • It is the purpose at thus survey to get hold at problems in teaching integrated science in middle school. For this purpose, problems and suggestions were collected by questionnaire which were made out by middle school science teachers. Through the analysis of the questionnaire, it was found that the present curriculum of science education in the college of education and the in-service training program were not suitable for training middle school science teacher. Form the results of the analysis, this survey concluded that the curriculum and program mentioned above need improvement as follows. (1) science education curriculum in the college of education should be set up with two part. One is the part that middle school science teachers are trained and the other is the part that high school science teachers are trained. (2) In-service training program should be set off into two kinds. One is the program that middle school science teachers are trained and the other program that high school science teachers are trained.

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Design of A Low-Voltage and High-Speed Pipelined A/D Converter Using Current-Mode Signals (저전압 고속 전류형 Pipelined A/D 변환기의 설계)

  • 박승균;이희덕;한철희
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.3
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    • pp.18-27
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    • 1994
  • An 8-bit 2-stage pipelined current mode A/D converter is designed with a new architecture, where the wideband track-and-hold amplifiers which have 2 integrators in parallel sample input signal twice per clock cycle. The conversion speed of the A-D converter is two times faster than that of conventional pipelined method. The converter is designed to be operated at the power supply voltage of 3.3V with the input dynamic range of 0-256$\mu$A. HSPICE simulation results show the performance of up to 55Msamples/s and power consumption of 150mW with the parameters of ISRC $1.5\mu$m BICMOS process. The chip area is 3${\times}4mm^{2}$.

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Agribusiness: An Ethical Approach to Marketing

  • Ngoe, Tata joseph
    • Agribusiness and Information Management
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    • v.5 no.1
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    • pp.11-19
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    • 2013
  • Price skimming practices, false claim on products, false information/communication, marketing overseas, and deception on products in marketing have received significant attention by the researchers of ethics in marketing studies. This research considers these phenomena as marketing instruments that grossly violate the practice of ethics in this domain. The two most crucial parts in marketing that have received greater attention are product safety and advertising. The paper also examines Ethical Marketing as the ability to make marketing decisions that are morally right and acceptable to all. In order words, ethics in marketing explains how moral standards can be applied in marketing decisions. It seeks to answer the research question by looking at some fundamental business ethics theories, namely, Virtue ethics, Utilitarian, and Deontological approaches to business ethics. Nevertheless, ethics in business is very controversial as many hold different view about what makes up the standard morals that corporations should take and so it is necessary for any organization to formulate its ethical codes to follow.

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Simultaneous position and vibration control of the flexible object while using dual-arm manipulators

  • Yukawa, T.;Uchiyama, M.;Obinata, G.
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10b
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    • pp.513-518
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    • 1993
  • In this paper, we consider the handling f a flexible object using dual-arm manipulators. We choose both the side arms as rigid, and the objects to be manipulated as flexible. Our purpose is to realize position control for the flexible object while suppressing its vibration. In particular, the problem taken up here is the stability of the control system while manipulating the object. We propose that the traditional approach to investigate the robot system be expanded to include the object's characteristics (thus transferring the stability of the robot system into the full assembly system). We define a handling characteristic while manipulating the object. Finally, the relationship between the handling characteristic and the positional constraint condition in the hold position of the arms is studied while considering the stability of the control system.

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Government-owned Bank Relationships and Firm Performance (정부소유 은행관계와 기업 경영성과)

  • Lee, Sang Wook
    • Knowledge Management Research
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    • v.14 no.1
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    • pp.57-72
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    • 2013
  • This paper examines the relationships between the Korean government-owned banks and the firm performance. We investigates this empirical analysis using a data set containing virtually all Korean publicly listed firms for the period of 2004-2006. We find the negative relationships between government-owned banks and firm performance. The strong relationships between the Korean government-owned banks and the Korean listed firms may lower firm performance. The Hold up costs may be present in the government-owned bank relationships. The government-owned bank relationships in the Korean listed firms may could shape the negative management decisions and firm performance. On the lines of concerns on the impact of government banks, this paper will provide new evidences on the impact of government-ownership of banks on the Korean Economy. Particularly, empirical analyses in this paper revealed new evidences on the recent firm-bank relationship or government banks researches.

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Sub-100nm Hybrid stamp fabrication by Hot embossing (Hot embossing 공정을 이용한 100nm 급 Hybrid stamp 제작)

  • Hong S.H.;Yang K.Y.;Lee Heon
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1168-1170
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    • 2005
  • Nanoimprint Lithography(NIL) has increasingly been recognized as a key manufacturing technology for nanosized feature. One of the most important task for nanoimprint lithography is to provide the imprinting stamp with low price. The Stamp fabricated with Si based material by e-beam lithography, RIE is extremely expensive and its throughput is very limited and PDMS replica is too soft to hold high imprinting pressure.(>5atm) In this study, we present the imprinting stamp which can be easily replicated from original mold and is based on PVC film. Replication of original Si mold to PVC film was done by Hot embossing technique, ($120^{\circ}C$ of Temperature, 20 atm applied) As small as 100nm patterns were successfully transferred into PVC film. The size of stamp was up to 100mm in diameter.

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A Development of SEM Applied Microjoining System (SEM을 이용한 미세 접합 시스템 개발)

  • 황일한;나석주
    • Journal of Welding and Joining
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    • v.21 no.4
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    • pp.63-68
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    • 2003
  • Scanning electron microscopy (SEM) has been used as a surface measurement instrument and a tool for lithography in semiconductor process due to its high density localized beam. For those purposes, however, the maximum current of SEM Is less than 100pA, which is not enough fo material processing. In this paper SEM was modified to increase the amount of current reaching a specimen from gun part where current is generated, the possibility of applying SEM to material processing, especially microjoining, was investigated. The maximum current of SEM after modifications was measured up to 10$\mu$A, which is about 10$^{5}$ times greater than before modifications. Through experiments such as eutectic solder wetting on thin 304 stainless steel foil and microjoining of 10$\mu$m thick 304 stainless steel, the intensity of electron beam of SEM proved to be great enough fur material processing as heat source. And a tight jig system was found necessary to hold materials close enough fur successful microloining.

Characteristics of Axial Solid Hold-up Distribution in a CFB Riser with 3-Loops (3개의 순화고리를 갖는 순환유동층 상승관에서의 축방향 고체 체류랑 분포 특성)

  • 이종민;김재성;김시문;김종진;송규근
    • Journal of Energy Engineering
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    • v.9 no.4
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    • pp.348-357
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    • 2000
  • 본 연구에서는 동해화력 순환유동층 보일러와 유사한 3개의 사이클론을 갖는 직사각형 구조의 순환유동층 반응기를 이용하여 동해화력 운전조건 -연소로 공기 속도, 일-이차 공기비, 전체 고체량(inventory), 입도 및 입도분포 등- 에 따른 축방향 고체 체류량 및 순환량 등의 수력학적 특성을 고찰하였다. 상승관에서의 공기유속(U$_{0}$)이 증가함에 따라, 또는 PA/[PA+SA]비가 증가함에 따라, 그리고 전체 고체량(inventory)이 증가함에 따라 고채 채류량 및 순환량은 증가하는 것으로 나타났다. 또한 넓은 입도 분포를 갖는 석탄 회재의 경우는 균일한 입도 분포의 입자들에 비해 입자 비산량 및 고체 순환량이 작을 것으로 나타났다. 한편, 층내에서의 고체 체루량 분포를 감소지수 a 및 K를 사용하여 나타낼 수 있었으며, a 및 K와 유속 및 입자간의 상관 특성치를 도출하여 유동 및 순환특성을 고찰하였다. 상기의 상관수는 균일한 입도의 모래에 비해 석탄회재가 비교적 큰 값을 나타내었으며, 상관수가 클수록 희박상 영역에서의 비산 및 고체 순환량이 작은 것으로 나타났다.다.

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A Study on the Simulation of Ink Penetration into the Uncoated Papers in Gravure Printing (그라비어 인쇄에서 비도피지의 잉크 침투 시뮬레이션에 관한 연구)

  • Seo, Yea-Ri;Youn, Jong-Tae
    • Journal of the Korean Graphic Arts Communication Society
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    • v.28 no.1
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    • pp.1-13
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    • 2010
  • Gravure printing and manufacturing of advanced electronic components in a way that is going extra hold position. It is to print the electronic components of the rapid productivity improvements as well as cost-saving and environment-friendly industries such as the transition is a big advantage. However the mechanism of gravure is difficult to study scientifically because of high speed and excessively small size of the cell. To approach the mechanism we experimented using gravure printability. The condition of variables of IGT is pressure and velocity. By using Flow-3D simulation software, we built up the theoretical model under the constant variables. Then, we compared the real test with the simulation results. Therefore, it is studied the mechanism of gravure scientifically and it can be analysed the effect of the variable conditions.

서버파워를 위한 작은 도통 손실을 갖는 위상 천이 풀 브릿지 컨버터

  • Kim, Yeong-Do;Jo, Gyu-Min;Kim, Deok-Yu;Kim, Jeong-Eun;Mun, Geon-U
    • Proceedings of the KIPE Conference
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    • 2011.07a
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    • pp.372-373
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    • 2011
  • 최근 분산 전력 시스템은 효율적인 전력의 관리를 위하여 전 부하 영역에서의 높은 효율이 요구 되고 있다. 하지만 분산 전력 시스템은 Hold up time 규제로 인하여 정상 동작 시 낮은 시비율로 동작하게 되며 이에 따라 환류 구간이 발생하게 되어 도통 손실을 야기하며 이는 효율의 감소를 가져오게 된다. 따라서 작은 도통 손실을 갖는 새로운 위상 천이 풀브릿지 컨버터를 본 논문에서 제안하여 환류 구간의 손실을 감소시켜 효율 향상을 취할 수 있도록 한다. 본 논문에서는 제안된 컨버터를 소개하고 동작 원리 및 실험을 통한 검증 결과를 제시한다.

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