• 제목/요약/키워드: take-off

검색결과 919건 처리시간 0.025초

A Structure of Personalized e-Learning System Using On/Off-line Mixed Estimations Based on Multiple-Choice Items

  • Oh, Yong-Sun
    • International Journal of Contents
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    • 제5권1호
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    • pp.51-55
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    • 2009
  • In this paper, we present a structure of personalized e-Learning system to study for a test formalized by uniform multiple-choice using on/off line mixed estimations as is the case of Driver :s License Test in Korea. Using the system a candidate can study toward the license through the Internet (and/or mobile instruments) within the personalized concept based on IRT(item response theory). The system accurately estimates user's ability parameter and dynamically offers optimal evaluation problems and learning contents according to the estimated ability so that the user can take possession of the license in shorter time. In order to establish the personalized e-Learning concepts, we build up 3 databases and 2 agents in this system. Content DB maintains learning contents for studying toward the license as the shape of objects separated by concept-unit. Item-bank DB manages items with their parameters such as difficulties, discriminations, and guessing factors, which are firmly related to the learning contents in Content DB through the concept of object parameters. User profile DB maintains users' status information, item responses, and ability parameters. With these DB formations, Interface agent processes user ID, password, status information, and various queries generated by learners. In addition, it hooks up user's item response with Selection & Feedback agent. On the other hand, Selection & Feedback agent offers problems and content objects according to the corresponding user's ability parameter, and re-estimates the ability parameter to activate dynamic personalized learning situation and so forth.

장주기/대용량 수소저장을 위한 액체/고체기반 Slush 수소의 저장 비용 분석 (An Economic Analysis on Slush Hydrogen Containing Liquid and Solid Phase for Long-Term and Large-Scale Storage)

  • 박성호;이창형;류주열;황성현
    • 한국수소및신에너지학회논문집
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    • 제33권3호
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    • pp.247-254
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    • 2022
  • Slush hydrogen containing liquid and solid hydrogen is expected to achieve zero boil-off by suppressing boil-off gas because heat of fusion for solid absorbe the heat ingress from atmosphere. In this paper, quantitative analysis on storage cost considering specific energy consumption between 1,000 m3 class liquid hydrogen storage system with re-liquefaction and slush hydrogen storage system during equivalent zero boil off period. Even though approximately 50% of total storage capacity should be converted into solid phase during the initial cargo bunkering, total energy consumption to convert into slush hydrogen is relatively 25% less than re-liquefaction energy for boil off hydrogen during zero boil off period. That's because energy consumption of slush phase change take up only 1.8% of liquefaction energy. moreover, annual revenue requirement including CAPEX, OPEX and electric cost for slush hydrogen storage could be more reduced approximately 32.5% than those of liquid hydrogen storage and specific energy storage cost ($/kg-H2) could also be lowered by about 41.7% compared with liquid hydrogen storage.

TQM의 시대는 지나가고 있는가? (Is TQM a Dying Fad?)

  • 박영택;노재헌
    • 한국품질경영학회:학술대회논문집
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    • 한국품질경영학회 1998년도 The 12th Asia Quality Management Symposium* Total Quality Management for Restoring Competitiveness
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    • pp.659-664
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    • 1998
  • Even though advocates of TQM emphasize the role of TQM more than before, the interest of general public have decreased in recent years. A few months ago, the Fortune introduced a survey result showing that management tools (including TQM) are to some extent fashion items, becoming chic or declasse with the march of the management zeitgeist. According to the article, TQM has cooled off and other approaches have risen to take the place. Is TQM a really dying fad? This paper discusses the problem.

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환경에 따른 MZT/LZT 디스크의 tribological 특성 (Tribological Behavior of MZ/LZT disk under Various Environmental Conditions)

  • 박용식;김대은
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1999년도 제29회 춘계학술대회
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    • pp.53-60
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    • 1999
  • As the flying height decreased, it is essential that hard disk drives perform reliable under various environmental conditions. In this paper the tribological characteristics of a head/disk interface are investigated under various temperature, relative humidity, altitude and outgas conditions. Specially, Contact-Start-Stop(CSS) tests were performed to assess the stiction, acoustic emission, slider take-off behavior, and track average amplitude(TAA). It is shown that the surface damage and head failure are accelerated by high temperature and humidity as well as low ambient pressure.

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에너지 낭비 'STOP' 조명절전 ESCO사업 'START'

  • 에너지절약전문기업협회
    • ESCO지
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    • 통권13호
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    • pp.26-29
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    • 2001
  • 네오정보시스템(대표 고재형)은 운전면허기능 온라인채점기(경찰청 등록 1호)로 국내 시장의 $80\%$를 장악하고 있는 ㈜네오텔레콤에서 지난해 1월 분사한 신생회사이다. 사내 연구인력이 자체 개발한 조명절전기(Neo Energy Saver)를 가지고 2000년 12월 에너지절약투자시장에 뛰어든 이 회사는 신생 ESCO로서 무리하지 않으면서 착실히 ESCO사업을 전개해 나가고 있다. 올 한 해가 시범적용의 탐색기였다면 내년부터는 본격 이륙기(Take-Off)가 될 것이라고 장담하고 있는 네오정보시스템의 에너지사업본부를 찾아가 본다.

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PSA-BiCMOS의 고온특성에 관한 연구 (High Temperature Characterization of PSA-BiCMOS)

  • 조정호;구용서안철
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 1998년도 추계종합학술대회 논문집
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    • pp.577-580
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    • 1998
  • This paper presents the characteristics of each MOS device and Bipolar device, then investigates about how these devices take effect on BiCMOS inverter from 300K to 470K. The turn-off and Logic swing characteristics of BiCMOS inverter are degraded by the electrical characteristics of the MOS to around 400K, but over that temperature enhanced by the characteristics of the Bipolar transistor.

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읽을거리 - 항공기 실전원리(13) - 공기역학을 거부한 수직이착륙(VTOL) 기술

  • 한국항공우주산업진흥협회
    • 항공우주
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    • 통권108호
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    • pp.66-67
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    • 2010
  • 수직이착륙, 영어로는 VTOL(Vertical Take-Off and Landing)이라 불리는 기술은 공기역학을 거부한 첨단 항공우주기술이다. 일반적으로 고정익 항공기는 날개에서 발생하는 양력으로 하늘을 날지만 VTOL 항공기는 순수한 엔진 추력만으로 수직으로 이착륙하거나 단거리에서 이륙할 수 있다. 다만 높은 기술적 완성도를 요구하는 만큼 현재까지 실전 배치된 군용기 중 이 기술이 적용된 군용기는 해리어(Harrier)와 V-22 오스프리(Osprey), Yak-38 정도가 고작이다. 수직이착륙 기술에 대해 소개한다.

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하드디스크 슬라이더의 부상 특성과 AE신호의 관계 (Relationship between Take-off Behavior of Hard-disk Slider and AE Signal)

  • 이상민;문재택;김대은
    • Tribology and Lubricants
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    • 제17권1호
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    • pp.40-55
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    • 2001
  • Acoustic emission(AE) signal has been widely utilized to monitor the interaction at the head/disk interface. In this work the relationship between the AE signal and the state of contact between the slider and the disk is presented. Results of the FFT(Fast Fourier Transform) analyses of the AE signal could be used to better understand the interfacial interaction. Also, it was found that wear particles affect the AE signal. Therefore, the signal can be used to monitor the wear particle presence at the interface.

환경에 따른 헤드/디스크 인터페이스의 마찰 특성 (Tribological Characteristics of Head/disk Interface under Various Environmental Conditions)

  • 박용식;김대은
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1998년도 제28회 추계학술대회
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    • pp.131-138
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    • 1998
  • It is essential that hard disk drives perform reliable under various temperature, humidity, and ambient pressure conditions. In this paper the tribological characteristics of a head/disk interface are investigated under various environmental conditions. Specially, Contact-Start-Stop(CSS) tests were performed to assess the stiction and slider take-off behavior. It is shown that the surface damage is accelerated by high temperature and humidity as well as low ambient pressure.

  • PDF