• 제목/요약/키워드: EEE

검색결과 113건 처리시간 0.025초

비선형 부하의 순시 전력 보상 (Instantaneous Power Compensation of Non-linear Load)

  • 김종겸;박영진;이은웅;정종호;김일중
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.152-153
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    • 2007
  • industrial site has led to a growing concern for harmonic distortion and the resulting impacts on system equipment and operation. Harmonic current is generated by the operation of non-linear load, it means that voltage and current waveforms exhibit a non-linear relationship. Harmonics cause increase losses in the customer and utility power system components. This paper describes application of instantaneous active and reactive theory for the compensation of harmonic currents in three-phase non-linear load.

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Computational evaluation of wind loads on buildings: a review

  • Dagnew, Agerneh K.;Bitsuamlak, Girma T.
    • Wind and Structures
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    • 제16권6호
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    • pp.629-660
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    • 2013
  • This paper reviews the current state-of-the-art in the numerical evaluation of wind loads on buildings. Important aspects of numerical modeling including (i) turbulence modeling, (ii) inflow boundary conditions, (iii) ground surface roughness, (iv) near wall treatments, and (vi) quantification of wind loads using the techniques of computational fluid dynamics (CFD) are summarized. Relative advantages of Large Eddy Simulation (LES) over Reynolds Averaged Navier-Stokes (RANS) and hybrid RANS-LES over LES are discussed based on physical realism and ease of application for wind load evaluation. Overall LES based simulations seem suitable for wind load evaluation. A need for computational wind load validations in comparison with experimental or field data is emphasized. A comparative study among numerical and experimental wind load evaluation on buildings demonstrated generally good agreements on the mean values, but more work is imperative for accurate peak design wind load evaluations. Particularly more research is needed on transient inlet boundaries and near wall modeling related issues.

A low-cost compensated approximate multiplier for Bfloat16 data processing on convolutional neural network inference

  • Kim, HyunJin
    • ETRI Journal
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    • 제43권4호
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    • pp.684-693
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    • 2021
  • This paper presents a low-cost two-stage approximate multiplier for bfloat16 (brain floating-point) data processing. For cost-efficient approximate multiplication, the first stage implements Mitchell's algorithm that performs the approximate multiplication using only two adders. The second stage adopts the exact multiplication to compensate for the error from the first stage by multiplying error terms and adding its truncated result to the final output. In our design, the low-cost multiplications in both stages can reduce hardware costs significantly and provide low relative errors by compensating for the error from the first stage. We apply our approximate multiplier to the convolutional neural network (CNN) inferences, which shows small accuracy drops with well-known pre-trained models for the ImageNet database. Therefore, our design allows low-cost CNN inference systems with high test accuracy.

우주방사선 환경 ICT 소자 영향 및 개발 동향 (ICT Device Impacts and Development Trends on Cosmic Radiation Environment)

  • 이윤식;정성근;황인록;양용석;이명래;서동우
    • 전자통신동향분석
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    • 제37권2호
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    • pp.21-29
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    • 2022
  • Cosmic radiation environments having extremely high-energy particles and photons cause severe malfunctions of electrical components in space and terrestrial regions. In this study, we revisit basic knowledge on radiation effects in ICT electrical devices, such as single event effect, total ionizing dose, and displacement damage. To avoid such soft errors and system failures, we introduce essential technical approaches from the perspectives of materials, layouts, circuits, and systems, including current research trends. By considering several techniques and Space EEE part standards, we suggest possible directions that can invoke New Space Era technology.

IEEE 802.16e에서 빠른 핸드오버 지원을 위한 선택적인 Association 기법 (An Adaptive Association Scheme for Fast Handover in IEEE 802.16e)

  • 박진욱;오승탁;추현승
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2009년도 춘계학술발표대회
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    • pp.1120-1123
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    • 2009
  • 다양한 기능의 휴대 단말 기기와 무선 환경의 보급으로 무선 인터넷 서비스에 대한 사용자들의 요구가 증가하고 있다. 이와 관련하여 IEEE 802.16 표준은 사용자에게 대용량 데이터 서비스를 제공하기 위한 무선 기술을 정의하고 있다. 또한, IEEE 802.16에 MS의 핸드오버 절차를 추가한 EEE 802.16e 표준 기술은 MS에 대한 핸드오버 절차를 지원하고 있다. 그러나 이러한 핸드오버 절차는 MS이 Serving BS과의 연결을 종료한 이후, 새로운 Target BS에 대한 핸드오버 절차를 수행하므로 사용자는 일시적인 데이터 전송 중단으로 인한 서비스 지연을 경험한다. 본 논문에서는 이러한 문제를 해결하고, 사용자에 대한 빠른 핸드오버 절차를 지원하기 위해 주변 BS들의 위치 정보를 MOB_NBR-ADV를 통하여 MS에게 전송하고, 이를 통해 각 BS들에 대한 MS의 접근 정도를 평가하여 특정한 BS에 대해서만 Association을 수행할 수 있는 기법을 제안한다.

아두이노 기반의 자율주행 유아용전동차 알고리즘 구현 (Implementation of Autonomous Ride-On Toy Car Algorithm Based on Arduino)

  • 최지예;이민서;홍나리;이혜연;전일용
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2023년도 추계학술발표대회
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    • pp.1153-1154
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    • 2023
  • 본 논문에서는 아두이노를 이용하여 유아용전동차가 실제 도로와 유사한 환경의 트랙을 자율주행할 수 있는 방법을 찾고자 한다. 라이다와 카메라를 이용하여 차선을 따라 주행하고, 장애물을 회피하고 신호등의 지시에 따라 정지하고 출발하며, 후진 주차를 완수하는 알고리즘을 완성하였다.

요양시설 거주 노인의 에너지와 영양소 섭취 실태 및 식품선호도 조사 (Study on Energy and Nutrient Intake and Food Preference of the Elderly in Care Facilities)

  • 권종숙;이승희;이강민;이윤나
    • 대한지역사회영양학회지
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    • 제21권2호
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    • pp.200-217
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    • 2016
  • Objectives: The purpose of this study was to assess energy and nutritional intake and investigate the preference for food and cooking methods of the residents in elderly care facilities. Methods: Data were collected from 72 residents (10 males and 62 females) aged ${\geq}70$ years in elderly care facilities using questionnaires, food photographs for estimating dietary intake and records for daily physical activity. Results: Average age of the study participants was 85.0 years and 41, 36 and 8 had dementia, hypertension and diabetes mellitus, respectively. 15%, 65% and 19% of subjects were physically mobile, enervated, and immobile, respectively. Daily energy intake was 1360.2 kcal in men and 1378.0 kcal in women, which were 68.0% and 86.1% of the estimated energy requirement (EER) of dietary reference intake for Koreans (KDRI) for ${\geq}75$ year old individuals, respectively. Estimated energy expenditure (EEE) of subjects calculated using formula from KDRI was 1361.9 kcal and EER calculated using estimated daily physical activity (EDPA) was 1232.9 kcal. Energy intake and EEE from KDRI were higher than EER from EDPA. Dietary intake of dietary fiber, calcium, potassium, zinc, vitamin $B_2$, niacin, vitamin C were lower, and protein, phosphorous, iron, sodium, vitamin A, vitamin $B_1$, vitamin $B_6$, vitamin E were higher than the corresponding ones of KDRI. Subjects liked meats, fishes and shellfish, and fruits, while subjects disliked milk, seaweeds and salted fish and salted vegetables. Cooked rice, soybean paste soup, beef, cooked sliced radish strip, and yogurt were favorite foods, with steam being a favorite cooking method. Subjects considered nutrition as the most important factor for improving food service quality. Conclusions: Results of this study could be utilized for improving food-service for the residents in elderly care facilities, and provide a basis for setting reference intake of energy and nutrients of the elderly having very low activity levels.

Computational evaluation of wind loads on a standard tall building using LES

  • Dagnew, Agerneh K.;Bitsuamlak, Girma T.
    • Wind and Structures
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    • 제18권5호
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    • pp.567-598
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    • 2014
  • In this paper, wind induced aerodynamic loads on a standard tall building have been evaluated through large-eddy simulation (LES) technique. The flow parameters of an open terrain were recorded from the downstream of an empty boundary layer wind tunnel (BLWT) and used to prescribe the transient inlet boundary of the LES simulations. Three different numerically generated inflow boundary conditions have been investigated to assess their suitability for LES. A high frequency pressure integration (HFPI) approach has been employed to obtain the wind load. A total of 280 pressure monitoring points have been systematically distributed on the surfaces of the LES model building. Similar BLWT experiments were also done to validate the numerical results. In addition, the effects of adjacent buildings were studied. Among the three wind field generation methods (synthetic, Simirnov's, and Lund's recycling method), LES with perturbation from the synthetic random flow approach showed better agreement with the BLWT data. In general, LES predicted peak wind loads comparable with the BLWT data, with a maximum difference of 15% and an average difference of 5%, for an isolated building case and however higher estimation errors were observed for cases where adjacent buildings were placed in the vicinity of the study building.

CAM과 비트 분리 문자열 매처를 이용한 DPI를 위한 2단의 문자열 매칭 엔진의 개발 (A Memory-Efficient Two-Stage String Matching Engine Using both Content-Addressable Memory and Bit-split String Matchers for Deep Packet Inspection)

  • 김현진;최강일
    • 한국통신학회논문지
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    • 제39B권7호
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    • pp.433-439
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    • 2014
  • 본 논문은 DPI (deep packet insepction)를 위한 CAM (content-addressable memory)과 병렬의 비트 분리(bit-split) 문자열 매처(matcher)를 이용한 2단의 문자열 매칭 엔진의 구조를 제안한다. 긴 타겟 패턴은 같은 길이의 서브 패턴으로 잘라지게 되고, 각 서브패턴은 1단의 CAM에 매핑된다. CAM으로부터의 매칭 인덱스의 시퀀스를 사용하여 2단에서 긴 패턴의 매칭 여부를 알 수 있다. CAM과 비트 분리 문자열 매처를 사용하여 이 기종의 메모리를 사용했을 경우에 메모리 요구량을 크게 줄일 수 있다.

우주용 상용 PEM 소자의 적용 및 검증기술 동향 (Application and Verification Trend of COTS PEM Devices in Space Program)

  • 조영준;이창호;이춘우;황도순
    • 항공우주산업기술동향
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    • 제6권1호
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    • pp.65-73
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    • 2008
  • 위성시스템의 성능 및 무게, 비용 등의 요구조건이 높아지면서 시스템 설계를 위한 고성능,고효율의 전기전자부품이 요구되고 있다. 이런 요구를 충족하기 위하여NASA나 ESA에서 사용하고 있는 고 신뢰성과 안전성에 바탕을 둔 기존의 표준소자에 비해 신기술과 고성능으로 빠르게 업그레이드되고 있는 상용부품의 수요가 증가하고 있다. 특히 상용집적소자인 PEM은 많은 우주프로그램에서 사용되고 있고 그 영역을 넓히기 위한 연구가 계속되고 있다. 본 논문에서는 우주 프로그램에 사용하기 위한 상용PEM소자의 고려사항과 검증동향에 대해 소개하고자 한다.

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