• 제목/요약/키워드: scale down

검색결과 840건 처리시간 0.031초

수평평판위 의 혼합대류 열전말 계산 을 위한 4-방정식 모델 의 개발 (Development of four-equation turbulence model for prediction of mixed convective heat transfer on a flat plate)

  • 성형진;정명균
    • 대한기계학회논문집
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    • 제7권2호
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    • pp.193-203
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    • 1983
  • The mixed convective heat transfer problems are characterized by the relatively significant contribution of buoyancy force to the transport processes of momentum and heat. Past analytical studies on this kind of problems have been carried out by employing either the conventional R-.epsilon. turbulence model which includes constant turbulent Prandtl number .sigma.$_{+}$ 1 or an extended R-.epsilon. turbulence model which takes account of the buoyancy effect in appropriate length scale equations. But in the latter case, the temperature variance .the+a.$^{2}$ over bar is approximated by a model under local equilibrium condition and the time scale ratio between velocity and temperature is assumed to be constant. These approximation is known to break down when the buoyancy effect is dominant. The present study is aimed at development of new computational turbulence closure level which can be applied to this rather complex turbulent process. The temperature variance is obtained directly by solving its dynamic transport equation and the time scale ratio which is variable in space is computed by a solution of a dynamic equation for the rate of scalar dissipation .epsilon.$_{\thetod}$ It was found that the computational results are in good agreement with available experimental data of wide range of unstable conditions.

노인주택 가구 디자인의 지침 비교 (A Comparative Study on Furniture Design Guidelines for the Elderly)

  • 이지숙
    • 한국생활과학회지
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    • 제16권6호
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    • pp.1243-1250
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    • 2007
  • The purpose of this study was to compare government guidelines and foreign guidelines related to furniture design for elderly. Future elderly will increasingly accustomed to the provisions of improved housing, education and welfare in comparison with our forebears. Also, there will be upgrading and different need for elderly furniture in our market. The results were as follows. The height of bed was based on the height of wheelchair seat, commonly. A adjustable bed was recommended for abled and disabled elderly. A pull-down shelf, drawer, empty space under chest, folding or sliding door in wardrobe and so on were recommended as a elderly furniture. It were good adjustable sink on human scale. There were need the empty space under sink for wheelchair users, one-touch or lever faucet, etc. There have given a little furniture design guidelines for elderly in Korea until now. But those guidelines haven't been considered enough human scale of elderly including wheelchair user. Because the close investigations have not made about abled and disabled elderly for their furniture design. So first of all, the government should be examined elderly physical size more accurately for elderly furniture design. The guideline for elderly furniture design should be for abled elderly and the disabled, too.

Review of Operational Multi-Scale Environment Model with Grid Adaptivity

  • Kang, Sung-Dae
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • 제10권S_1호
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    • pp.23-28
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    • 2001
  • A new numerical weather prediction and dispersion model, the Operational Multi-scale Environment model with Grid Adaptivity(OMEGA) including an embedded Atmospheric Dispersion Model(ADM), is introduced as a next generation atmospheric simulation system for real-time hazard predictions, such as severe weather or the transport of hazardous release. OMEGA is based on an unstructured grid that can facilitate a continuously varying horizontal grid resolution ranging from 100 km down to 1 km and a vertical resolution from 20 -30 meters in the boundary layer to 1 km in the free atmosphere. OMEGA is also naturally scale spanning and time. In particular, the unstructured grid cells in the horizontal dimension can increase the local resolution to better capture the topography or important physical features of the atmospheric circulation and cloud dynamics. This means the OMEGA can readily adapt its grid to a stationary surface, terrain features, or dynamic features in an evolving weather pattern. While adaptive numerical techniques have yet to be extensively applied in atmospheric models, the OMEGA model is the first to exploit the adaptive nature of an unstructured gridding technique for atmospheric simulation and real-time hazard prediction. The purpose of this paper is to provide a detailed description of the OMEGA model, the OMEGA system, and a detailed comparison of OMEGA forecast results with observed data.

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동적 경로안내시스템에서 벡터 지오데이터의 관리를 위한 다중 해상도 모델 (A Multi-Resolution Database Model for Management of Vector Geodata in Vehicle Dynamic Route Guidance System)

  • 주용진;박수홍
    • 대한공간정보학회지
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    • 제18권4호
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    • pp.101-107
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    • 2010
  • 본 연구의 목적은 벡터 도메인 안에 대규모 도로 선형 사상을 대상으로 실시간 데이터 변경, 관리가 가능한 네트워크의 다중 표현 데이터베이스 모델을 구축하는 것이다. 즉, 최상위 레벨의 네트워크 데이터로부터 이에 대응하는 하위 베이스 네트워크 데이터로 순차적으로 데이터 통합과 자동 매칭을 수행하는 상의하달 방식(top-down)을 기초로 하는 프레임워크를 제시하며, 이를 통해 변화 가능한 축척(variable-scale)의 지도를 생성하는 모델을 제안하였다. 구현된 MRDB(Multi-Resolution Database) 모델을 차량 항법 서비스에 적용하여 실제 동적 경로 안내 시스템에 활용 가능함을 확인할 수 있었다.

The effects of active release technique on the gluteus medius for pain relief in persons with chronic low back pain

  • Tak, Sajin;Lee, Yongwoo;Choi, Wonjae;Lee, Gyuchang
    • Physical Therapy Rehabilitation Science
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    • 제2권1호
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    • pp.27-30
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    • 2013
  • Objective: Low back pain is a primary of source of dysfunction and economic costs. Gluteus medius muscle co-activation and activity pattern change caused the low back pain. Active release technique (ART) is a patented, non-invasive, soft tissue treatment process that both locates and breaks down the scar tissue and adhesions. The purpose of this study was to assess the effects on chronic low back pain using ART on gluteus medius so that suggest usable treatment method for treating chronic low back pain. Design: One group pretest-posttest design. Methods: Twelve patients with chronic low back pain were participated in this study. Subjects in ART group were received 2 times a week for 3 weeks treatments with either ART on gluteus medius muscle trigger points. Outcome measures were conducted by pain intensity with a pain visual analogue scale and pressure pain threshold on gluteus medius. Results: Completion of the intervention, the visual analogue scale was decreased in ART group (p<0.05). Also pressure pain threshold was decreased in ART group (p<0.05). Conclusions: Our results suggest that the response to ART may be usable to treat low back pain. ART was presented to reduce pain level of low back in people with chronic low back pain. Further study is required to management for low back pain due to gluteus medius and more ART study.

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상용차량의 하중을 측정하기 위한 탑재형 자중계 개발 (Development of Onboard Scales to Measure the Weight of Trucks)

  • 서명국;신희영;이호연;고재일;투멘자르갈 엔크바타르
    • 드라이브 ㆍ 컨트롤
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    • 제18권1호
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    • pp.9-16
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    • 2021
  • Overloaded vehicles increase the maintenance cost of road structures, and they are a major factor in causing damage to the roads and bridges. In addition, overloaded vehicles compromise the braking capability of the vehicle; thus, threatening the safety of the driver. In order to prevent overloading of vehicles, the government is cracking down on the roads by using a device that measures the weight of vehicles. But this process is inconvenient because the place where the equipment is installed is far away from where the cargo is loaded. Due to the limitations of these fixed weighing devices, there is a growing need for technology that can monitor vehicle weight distribution and overload conditions in real time. In this work, we develop an onboard scale that can measure the load (weight) of trucks in real time. The onboard scale consists of high sensors, a signal processing unit, and a display, and it measures the load using height-displacement of the vehicle's leaf spring suspension.

측방보행 훈련이 급성기 뇌졸중 환자의 균형 자신감, 낙상 효능감, 낙상 위험도에 미치는 영향: 무작위 대조 예비 연구 (Effect of Side Walking Training on Balance Confidence, Falls Efficacy and Fall Risk in Acute Stroke Patients: A Randomized Controlled Pilot Study)

  • 주민철;정경만
    • 한국의료질향상학회지
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    • 제27권1호
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    • pp.43-50
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    • 2021
  • Purpose: The aim of this study was to determine the effect of side walking on balance confidence, falls efficacy and fall risk in acute stroke patients. Methods: The study included 14 patients with acute stroke who were randomly allocated to a side walking group (Experimental group, N=7) and a forward walking group (Control group, N=7). Both groups performed the exercise 5 times a week for 2 weeks. Outcomes were assessed using Korean-Activities-specific Balance Confidence Scale (K-ABC), Korean-Fall Efficacy Scale (K-FES), Korean-Fullerton Advanced Balance Scale (K-FAB). Results: After 2 weeks of training, both groups showed significantly improved ABC, FES, FAB (p<.05 in both groups). However, the ABC, FES, FAB in the experimental group was significantly better than in the control group (p<.05). Conclusion: These findings indicate that side walking training may be effective at improving balance confidence and decreasing fall down risk in early stroke patients. Therefore, side walking training may be recommended as an intervention in reducing the incidence of falls in acute stroke patient.

Development of a generalized scaling law for underwater explosions using a numerical and experimental parametric study

  • Kim, Yongtae;Lee, Seunggyu;Kim, Jongchul;Ryu, Seunghwa
    • Structural Engineering and Mechanics
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    • 제77권3호
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    • pp.305-314
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    • 2021
  • In order to reduce enormous cost of real-scale underwater explosion experiments on ships, the mechanical response of the ships have been analyzed by combining scaled-down experiments and Hopkinson's scaling law. However, the Hopkinson's scaling law is applicable only if all variables vary in an identical ratio; for example, thickness of ship, size of explosive, and distance between the explosive and the ship should vary with same ratio. Unfortunately, it is infeasible to meet such uniform scaling requirement because of environmental conditions and limitations in manufacturing scaled model systems. For the facile application of the scaling analysis, we propose a generalized scaling law that is applicable for non-uniform scaling cases in which different parts of the experiments are scaled in different ratios compared to the real-scale experiments. In order to establish such a generalized scaling law, we conducted a parametric study based on numerical simulations, and validated it with experiments and simulations. This study confirms that the initial peak value of response variables in a real-scale experiment can be predicted even when we perform a scaled experiment composed of different scaling ratios for each experimental variable.

전복 양식업의 경영비 분석과 정책 시사점 연구 (The Research on the Cost Analysis of the Abalone Aquacultural Management in Korea)

  • 옥영수
    • 수산경영론집
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    • 제46권2호
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    • pp.13-29
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    • 2015
  • The abalone aquaculture has been very rapidly developed in Korea. Annual production quantity was less 200 tons before 2000th, it have been increased to over 9,000 tons in 2014. Also Abalone export amounts have been over 20 million dollars. The reason of rapid growth of Abalone aquaculture in Korea is due to high level profit ratio. Then now many fishing officers and other aquaculture fishers want to participate with abalone aquaculture newly. However Recent Abalone aquaculture in Korea is faced some problems. Aspects of production environmental status of fishing grounds are more aggravate, and then abalone aquaculture is exposed to various disease, and death rate of young abalone is higher. And aspect of management, the aquaculture cost is more increase. The demand of abalone also is depressing recently, this cause to come down the production price. In this viewpoint, Management analysis of abalone aquaculture in Korea is helpful for decision making of general aquaculture fisher want to participate newly. The analysis is practiced two aspects. One is index analysis, and the other is Break-even-point(BEP) analysis. The result of index analysis, average net profit rate has shown 28.0%, however the Regional difference has excessive. That is, Wando(major) has shown 39.4%, and Haenam province has shown 14.2%. On the other hand, the more scale has shown higher profit rate by aquaculture scale. And the result of BEP analysis, average has shown 93 cage number per abalone aquaculture household, and Wando(major) has shown 56 cage number, Haenam province has shown 131 cage number. The lower production abalone price of recent means higher BEP level.

1/5축소 모형실험에 의한 조립식 터널라이닝 (PCL)의 내진성능 평가 (Seismic performance evaluation of Precast Concrete Lining (PCL) using the 1/5 scale down model test)

  • 이용준;정형식;이두화;조병완
    • 한국터널지하공간학회 논문집
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    • 제6권1호
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    • pp.61-70
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    • 2004
  • 최근 현장 타설 콘크리트 터널 라이닝의 시공 및 유지관리상 문제점을 개선하기 위해 노르웨이에서 개발된 프리캐스트콘크리트라이닝에 대한연구가 활발히 진행되고 있다. 그러나 북유럽지역에서는 지진이 거의 발생되지 않기 때문에 PCL공법 적용시 지진하중으로 인한 영향을 고려하지 않았다. 따라서 PCL공법을 국내에 도입하기 위해서는 지진하중으로 인한 PCL의 영향분석을 선행하여야 할 것으로 판단되어 본 연구에서는 지진하중으로 인한 PCL의 안정성 검토를 수행하고자 하며 이를 위해 실물을 1/5로 축소한 모델체에 대한 진동대 실험을 수행하였으며 PCL의 내진성능평가를 수행하였다. 연구결과, 대섬도터널에서 PCL공법을 적용할 경우, 국내의 내진설계 기준에 만족하는 결과를 얻을 수 있었다.

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