• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.63-69
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• 1998

The area optimization of the power distribution network is an important problem in the layout design of VLSI systems. In this paper we propose noval methods to solve the problem of designing minimal area power distribution nets, while satisfying voltage drop and electromigration constraints. We propose two novel greedy heuristics for power net design-one based on bottom-up tree construction using greedy merging and the other based on top-down linearly separable partitioning.

• Journal of KIISE:Software and Applications
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• v.28 no.5
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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.

• The Journal of Korean Physical Therapy
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• v.34 no.5
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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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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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.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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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.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.4
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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.

• Electrical & Electronic Materials
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• v.7 no.2
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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.

• Nuclear Engineering and Technology
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• v.53 no.3
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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.

• The Magazine for Energy Service Companies
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• s.57
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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.

• The Korea Genome Conference
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• 2002.08a
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• pp.46.2-46.2
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• 2002