• 제목/요약/키워드: top-down

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VLSI회로의 전력분배 합성과 면적 최적화에 관한 연구 (A study on the Power Distribution Synthesis and Area Optimization of VLSI Circuits)

  • 김현호;이천희
    • 한국컴퓨터정보학회논문지
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    • 제3권4호
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    • pp.63-69
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    • 1998
  • 전력분배 네트워크의 면적 최적화는 VLSI 시스템의 레이아웃 디자인에 중요한 문제이다. 본 논문에서는 전압 하강과 전기 이동 제약을 만족하는 전력분배 네트의 최소 면적을 디자인 하기위해 문제를 해결하는 새로운 방법을 제안한다. 전력 네트 디자인에 대한두가지의 새로운 greedy heuristics을 제안했는데 하나는 bottorm-up 트리 구조와 다른 하나는 top-down 분리 분할 기법을 기본으로 한 것이다.

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웹 에이전트를 위한 통합방식 문서 클러스터링 (A Hybrid Document Clustering for a Web Agent)

  • 양찬범;이성열;박영택
    • 한국정보과학회논문지:소프트웨어및응용
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    • 제28권5호
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    • pp.422-430
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    • 2001
  • 웹 에이전트는 사용자가 웹을 브라우징하는 행위를 모니터하여 사용자의 관심 정보를 학습하고 사용자가 필요로 하는 웹 상의 정보를 자동 제공하는 지능형 시스템이다. 웹 에이전트가 사용자의 선호도를 학습하기 위해서는 귀납적 기계학습을 수행하는데, 이때 학습의 효율을 높이기 위해서는 사용자가 관심있어하는 문서들을 유사한 문서들로 클러스터링하여 학습 시스템에 제공하여야 한다. 본 논문에서는 웹 에이전트의 학습 시스템에 입력되는 학습대상 문서들을 보다 정확하고 효율적으로 클러스터링하여 제공하기 위해서 Top-down 방식과 Bottom-up 방식을 통합 적용한 통합방식 문서 클러스터링과 초기 클러스터 생성을 위한 평가함수를 제시한다. Top-down 방식으로는 개념적 클러스터링 알고리즘인 COBWEB을 적용하고, Bottom-up 방식으로는 교차기반(Intersection-based) 클러스터링 방식인 Etzioni의 클러스터링 알고리즘을 적용하였다.

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The Effect of One Leg Deadlift Exercise on the Muscle Activity of Lower Extremities according to the Weight Characteristics

  • Park, Tae Geun;Lee, Jae Kwang
    • The Journal of Korean Physical Therapy
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    • 제34권5호
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    • pp.267-271
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    • 2022
  • Purpose: This study examined the effects of a kettlebell and aqua bag on the gluteus maximus, gluteus medius, and vastus medialis lower extremity muscle strength during a one-leg deadlift, a top-down exercise. Methods: Twenty healthy adults were enrolled in the one-leg deadlift exercise under two conditions. The muscle activity of the gluteus maximus, gluteus medius, and vastus medialis was measured by surface electromyography (S-EMG). A paired t-test was used for statistical analysis, and the statistical significance criteria were set to p<0.05. Results: A comparison of the muscle activity according to the degree of contraction of the gluteus maximus revealed low muscle activity in AD exercise compared to KD exercise (p<0.05), and there was no significant difference in the gluteus medius and vastus medialis (p<0.05). Conclusion: These results suggest that when the one-leg deadlift exercise is performed according to the weight characteristics, the gluteus maximus is suitable for intervention using a kettlebell, and the gluteus medius and vastus medialis are more suitable for intervention by providing instability using an aqua bag.

지하철골공사 공사비산정기준 마련을 위한 현장조사 연구 (A Study on the Establishment of Construction Cost Estimation Standard of Underground Steel Construction through Field Survey)

  • 송태석;한상준;안방율
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2023년도 봄 학술논문 발표대회
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    • pp.339-340
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    • 2023
  • Steel construction is one of the commonly used methods in building construction due to its efficiency in terms of time and cost. In particular, the top-down method using steel frames is widely used in the construction of underground structures in urban areas to shorten the construction period. However, there is currently no standardized cost estimation for subway steel frame construction in Korea, causing difficulties in determining the expected cost. In this study, we aim to provide basic data for establishing a cost estimation standard for subway steel frame construction through on-site surveys of subway steel frame construction commonly used in urban areas.

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홍수완충 공간관리 및 평가기술 적용을 위한 실무지원 도구 개발 시나리오 도출 (Deriving Scenarios for Developing Practical Support Tools for Flood Buffer Space Management and Evaluation Technology Application)

  • 문치국;최진우;김재명;한근수
    • 한국재난정보학회:학술대회논문집
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    • 한국재난정보학회 2022년 정기학술대회 논문집
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    • pp.425-426
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    • 2022
  • 본 논문에서는 홍수터, 홍수관리구역, 유지, 습지, 녹지 등의 용어로 지칭되는 홍수완충 공간관리 및 계획수립 시 활용할 수 있는 실무지원 도구 개발을 위한 시나리오를 도출하기 위해 국내·외 선행 연구과 오픈소스 GIS 기반 기술개발 현황을 조사하여 개별 연구에서 수행한 개발 시나리오를 분석하였다. 세부 개발 시나리오 분석 시, Top-Down 방식으로 실시하고 중복되는 시나리오는 병합을 실시하였다. 또한 세분화 완료한 시나리오는 단계를 구분하고 명칭과 부호를 부여하였다. 명칭과 부호 부여가 끝난 시나리오는 홍수완충 공간관리 실무지원 도구 개발 내부 모듈 설계에 적용하였다.

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외부 입력기기 사용 정보 기반 셋톱박스 대기모드 전환 기술 (A Standby Mode Transition Scheme for Set-top Box Power Saving by the Use Information of External Device)

  • 김용호;최윤범;오남걸;김훈
    • 정보통신설비학회논문지
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    • 제9권4호
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    • pp.124-130
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    • 2010
  • This paper considers a power saving technique of set-top box (STB) that turns the signal into content which is then displayed on the television (TV) screen. A traditional power saving scheme, Auto Power Down (APD), was devised to reduce the power consumption of STB. APD checks whether the user is watching TV over a period of time and enforces STB into stand-by mode when the check result reveals the user is not watching TV. This paper proposes an enhanced power saving scheme that transits STB operation mode to 'stand-by' immediately when STB recognizes the change of TV's external input signal. The proposed scheme does not require the monitoring time to check the users' watching TV, and transits to standby mode faster than the conventional APD, which results in better performance in power saving. The simulation result shows that the proposed scheme achieves 2 to 11% improvement in power consumption compared with the conventional APD.

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실리콘 다층절연막의 전기전도 특성 (The electrical conduction characteristics of the multi-dielectric silicon layer)

  • 정윤해;한원열;박영걸
    • E2M - 전기 전자와 첨단 소재
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    • 제7권2호
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    • pp.145-151
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    • 1994
  • The multi-dielectric layer SiOz/Si3N4/SiO2(ONO) is used to scale down the memory device. In this paper, the change of composition in ONO layer due to the process condition and the conduction mechanism are observed. The composition of the oxide film grown through the oxidation of nitride film is analyzed using auger electron spectroscopy(AES). AES results show that oxygen concentration increases at the interface between oxide and nitride layers as the thickness -of the top oxide layer increases. Results of I-V measurement show that the insulating properties improve as the thickness of the top oxide layer increases. But when the thickness of the nitride layer decreases below 63.angs, insulating peoperties of film 28.angs. of top oxide and film 35.angs. turn over showing that insulating property of film 28.angs. of top oxide is better than that of film 35.angs. of top oxide. This phenomenon of turn over is thought as the result of generation of surface state due to oxygen flow into nitride during oxidation process. As the thickness of the top oxide and nitride increases, the electrical breakdown field increases, but when the thickness of top oxide reaches 35.angs, the same phenomenon of turn over occurs. Optimum film thickness for scaled multi-layer dielectric of memory device SONOS is estimated to be 63.angs. of nitride layer and 28.angs. of top oxide layer. In this case, maximum electrical breakdown field and leakage current are 18.5[MV/cm] and $8{\times}{10^-12}$[A], respectively.

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Scaling analysis of the pressure suppression containment test facility for the small pressurized water reactor

  • Liu, Xinxing;Qi, Xiangjie;Zhang, Nan;Meng, Zhaoming;Sun, Zhongning
    • Nuclear Engineering and Technology
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    • 제53권3호
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    • pp.793-803
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    • 2021
  • The small PWR has been paid more and more attention due to its diversity of application and flexibility in the site selection. However, the large core power density, the small containment space and the rapid accident progress characteristics make it difficult to control the containment pressure like the traditional PWR during the LOCA. The pressure suppression system has been used by the BWR since the early design, which is a suitable technique that can be applied to the small PWR. Since the configuration and operating conditions are different from the BWR, the pressure suppression system should be redesigned for the small PWR. Conducting the experiments on the scale down test facility is a good choice to reproduce the prototypical phenomena in the test facility, which is both economical and reasonable. A systematic scaling method referring to the H2TS method was proposed to determine the geometrical and thermohydraulic parameters of the pressure suppression containment response test facility for the small PWR conceptual design. The containment and the pressure suppression system related thermohydraulic phenomena were analyzed with top-down and bottom-up scaling methods. A set of the scaling criteria were obtained, through which the main parameters of the test facility can be determined.

에너지경영시스템(EMS)

  • 김하연
    • ESCO지
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    • 통권57호
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    • pp.24-27
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    • 2009
  • 에너지경영시스템(Energy Management System)이란 최고경영자가 경영방침에 에너지관리 목표를 포함시켜 전사적인 에너지 관리를 추진하는 톱다운(Top-Down) 방식의 에너지관리시스템이다. 에너지 절감을 위해 에너지관리공단에서 도입 및 계획하고 있는 EMS에 대해 알아본다.

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