• Title/Summary/Keyword: EEE

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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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    • v.16 no.6
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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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    • v.43 no.4
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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.

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

  • Yi, Y.;Jeong, S.K.;Hwang, I.;Yang, Y.S.;Lee, M.L.;Suh, D.
    • Electronics and Telecommunications Trends
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    • v.37 no.2
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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.

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

  • Park, Jinwook;Oh, Seungtak;Choo, Hyunseung
    • Proceedings of the Korea Information Processing Society Conference
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    • 2009.04a
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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.

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

  • Jiye Choi;Minseo Lee;Nari Hong;Hyeyeon Lee;Il Yong Chun
    • Proceedings of the Korea Information Processing Society Conference
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    • 2023.11a
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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.

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

  • Kwon, Jong-Sook;Lee, Seung Hee;Lee, Kang Min;Lee, Yoonna
    • Korean Journal of Community Nutrition
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    • v.21 no.2
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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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    • v.18 no.5
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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.

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

  • Kim, HyunJin;Choi, Kang-Il
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.7
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    • pp.433-439
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    • 2014
  • This paper proposes an architecture of two-stage string matching engine with content-addressable memory(CAM) and parallel bit-split string matchers for deep packet inspection(DPI). Each long signature is divided into subpatterns with the same length, where subpatterns are mapped onto the CAM in the first stage. The long pattern is matched in the second stage using the sequence of the matching indexes from the CAM. By adopting CAM and bit-split string matchers, the memory requirements can be greatly reduced in the heterogeneous string matching environments.

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

  • Cho, Young-Jun;Lee, Chang-Ho;Lee, Choon-Woo;Hwang, Do-Soon
    • Current Industrial and Technological Trends in Aerospace
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    • v.6 no.1
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    • pp.65-73
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    • 2008
  • As the system requirements of performance, weight, cost are increasing, the needs of electronic parts which have high performance and efficiency are growing. To satisfy such requirements, demand of high performance and rapid upgraded commercial parts is also increasing compared to NASA or ESA standard parts. Especially, commercial PEM(Plastic Encapsulated Microcircuit) parts are applied in many space programs and research is continuing to broaden its application area. In this paper, concerns and verification trends of commercial PEM parts in space applications are introduced.

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Reversible Image Coding with Progressive Build-up (단계적 전송기능을 갖는 영상 데이터의 가역 부호화)

  • 박지환;김진홍;김두영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.1
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    • pp.111-119
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    • 1994
  • In this paper we propose a reversible image coding methods with progressive build-up function by bit-plane of multi-lavel image. Firstly, the differencial conversion is applied to reduce the entropy of source images. Then the bit-plane sequences of converted images are coded by means of the newly designed VFRL(Variable to Fixed Run-Llength) code and the RDHC(Run-length Dynamic Huffman Coding). We aim to the simple construction to reduce the complexity. The computer simulated results show that the proposed methods are very effective to the multi-level digital images. For "GIRL" and "COUPLE" of 1EEE monochromatic standard images, the compressibility are superior to the results obtained by the well-known universal codes.own universal codes.

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