• 제목/요약/키워드: Circulation method

검색결과 981건 처리시간 0.031초

기후변화에 따른 도당천 유역 미래 물순환율 평가 (Assessment of Future Water Circulation Rate in Dodang Watershed under Climate Change)

  • 곽지혜;황순호;전상민;김석현;최순군;강문성
    • 한국농공학회논문집
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    • 제62권4호
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    • pp.99-110
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    • 2020
  • The objective of this study is to analyze the trend of changes in the water circulation rates under climate change by adopting the concept of WCR defined by the Ministry of Environment. With the need for sound water circulation recovery, the MOE proposed the idea of WCR as (1-direct flow/precipitation). The guideline for calculating WCR suggests the SCS method, which is only suitable for short term rainfall events. However, climate change, which affects WCR significantly, is a global phenomenon and happens gradually over a long period. Therefore, long-term trends in WCRs should also be considered when analyzing changes in WCR due to climate change. RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios were used to simulate future runoff. SWAT (Soil and Water Assessment Tool) was run under the future daily data from GCMs (General Circulation Models) after the calibration. In 2085s, monthly WCR decreased by 4.2-9.9% and 3.3-8.7% in April and October. However, the WCR in the winter increased as the precipitation during the winter decreased compared to the baseline. In the aspect of yearly WCR, the value showed a decrease in most GCMs in the mid-long future. In particular, in the case of the RCP 8.5 scenario, the WCR reduced 2-3 times rapidly than the RCP 4.5 scenario. The WCR of 2055s did not significantly differ from the 2025s, but the value declined by 0.6-2.8% at 2085s.

0.5 MWth 케미컬루핑 연소시스템 적용을 위한 산소전달입자의 수력학 특성 및 고체순환 특성 (Hydrodynamics and Solid Circulation Characteristics of Oxygen Carrier for 0.5 MWth Chemical Looping Combustion System)

  • 류호정;김정환;황병욱;남형석;이도연;조성호;백점인
    • 한국수소및신에너지학회논문집
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    • 제29권6호
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    • pp.635-641
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    • 2018
  • To select the operating condition of 0.5 MWth chemical looping combustion system, minimum fluidization velocity, transition velocity to fast fluidization and solid circulation rate were measured using mass produced new oxygen carrier (N016-R4) which produced by spray drying method for 0.5 MWth chemical looping combustion system. A minimum fluidization velocity decreased as the pressure increased. The measured transition velocity to fast fluidization was 2.0 m/s at ambient temperature and pressure. The measured solid circulation rate increased as the solid control valve opening increased. We could control the solid circulation rate from 26 to $93kg/m^2s$. Based on the measured minimum fluidization velocity and transition velocity to fast fluidization, we choose appropriate operating conditions and demonstrated continuous solid circulation at high pressure condition (5 bar-abs) up to 24 hours.

단상 인버터 시스템에서 순환 전류 제어 기법에 관한 연구 (The Study of the Circulation Current Control Scheme on Single Phase Inverter System)

  • 이우철
    • 조명전기설비학회논문지
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    • 제28권2호
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    • pp.60-69
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    • 2014
  • This paper proposed the circulation current control scheme in the single phase inverter system. The load experiment of the power conversion system including the UPS usually uses the passive components such as resistors and inductors. Therefore, the energy consumption is serious problem. In addition, the system is out of order when it is installed in the local area, and the load experiment can not perform adequately after troubleshooting, because there is no the load equipment, and the power capacity is not enough in the local area. The paper does the research on the circulation current control scheme, it does not need the load equipment, and the load current can reuse as the input current of the equipment. Instead of the conventional method the voltage-voltage and voltage-current control scheme introduced the parallel converter concept is newly proposed, and the validity of the proposed control scheme is investigated by both simulation and experimental results.

원격상관을 이용한 동아시아 6월 강수의 예측 (A Prediction of Precipitation Over East Asia for June Using Simultaneous and Lagged Teleconnection)

  • 이강진;권민호
    • 대기
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    • 제26권4호
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    • pp.711-716
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    • 2016
  • The dynamical model forecasts using state-of-art general circulation models (GCMs) have some limitations to simulate the real climate system since they do not depend on the past history. One of the alternative methods to correct model errors is to use the canonical correlation analysis (CCA) correction method. CCA forecasts at the present time show better skill than dynamical model forecasts especially over the midlatitudes. Model outputs are adjusted based on the CCA modes between the model forecasts and the observations. This study builds a canonical correlation prediction model for subseasonal (June) precipitation. The predictors are circulation fields over western North Pacific from the Global Seasonal Forecasting System version 5 (GloSea5) and observed snow cover extent over Eurasia continent from Climate Data Record (CDR). The former is based on simultaneous teleconnection between the western North Pacific and the East Asia, and the latter on lagged teleconnection between the Eurasia continent and the East Asia. In addition, we suggest a technique for improving forecast skill by applying the ensemble canonical correlation (ECC) to individual canonical correlation predictions.

박물관 대공간의 공간구조 형식과 특성에 관한 연구 (A Study on the Type and Characteristics of the Spatial Structure in Major Space of Museums)

  • 박세민;정성욱
    • 한국실내디자인학회논문집
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    • 제17권6호
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    • pp.178-187
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    • 2008
  • This study aims to analyze general features and forms of spatial structure of major space in museums and for the scope of this study, set up major space and the surrounding areas structured around major space and for the target of analysis, selected 10 museums of overseas examples from 19th century to 2006. And this study on focus, on the circulation structure and visual structure will be analyzed in qualitative method by focusing on the floor plan and section structures; deepening process of analysis, visual structure will turn into numerical value to analyze the spatial structure of the major space. The results of this study are as follow. First, vertical elements should be critically considered in a circulation plan for functional performance of dimensional circulation distribution in a major space. Second, a plan by location of vertical and horizontal moving elements related to a major space affects a circulation relation more than a connection type between a major space and an exhibition area. Third, it could be categorized into 4 types by considering the features of spatial structure followed by connecting relationship between areas. Fourth, comparable figures were drawn out among large space and surrounding areas but it couldn't draw out types.

총경동맥루: 증례 보고 (Aneurysm of the Common Carotid Artery: A Case Report)

  • 배두현
    • Journal of Chest Surgery
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    • 제3권1호
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    • pp.39-46
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    • 1970
  • Aneurysm of the common carotid artery is uncommon. In surgery for carotid aneurysm there is the risk of endangering cerebral circulation during the period of arterial occlusion necessary for the resection. Therefore a method which will allow adequate cerebral circulation during carotid artery anastomisis is obviously to be desired. A case of aneurysm of the common carotid artery is presented in which the aneurysm was partially resected and the artery was reconstructed by end to end anastomosis. while cerebral circulation was maintained by an internal polyethylene shunt. The occurrence of this aneurysm was associated with a chronic stasis ulcer of the left fore leg. On this basis the aneurysm was thought to be of mycotic origin though this has not been proved histologically or by laboratory methods. The literature on aneurysm of the carotid artery is briefly reviewed.

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간섭 전류 치료의 자극부위에 따른 활력징후의 변화 (The Change of the Vital Sign by the Variables of Stimulated Areas in Interferential Current Treatment)

  • 박영한
    • 대한물리치료과학회지
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    • 제16권3호
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    • pp.1-9
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    • 2009
  • Background: The purpose of this study is to have examined the influence on the blood circulation by comparing the differences between stimulating the sympathetic ganglion and the muscle group among the stimulation variables in interferential current stimulation. Method: The object of the study is the twenties(M=8, F=12), who are in great condition and have no pathological report for the blood circulation influence. The intensity of the inferential current stimulation is the medium degree, 100 bps constant current, which is the comfort and degree to confirm the muscle contraction. The areas stimulated are the stellate ganglion area in the seventh cervical vertebrae and the forearm muscle area. Results: We have made sure that there is no change in blood pressure and pulse and that the change in the skin temperature occurred highly. Conclusion: In considering the change of the blood circulation in case of stimulation area by the inferential current stimulation, we have seen that stimulating the sympathetic ganglion area is more effective than stimulating muscle area directly.

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혹한기 지역에서의 자연순환형 태양열 시스템 동파방지 (Freeze Protection for Passive Solar Water Heating System in Bitter Cold Areas)

  • 권재욱;김종현;홍희기
    • 한국태양에너지학회 논문집
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    • 제31권5호
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    • pp.41-46
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    • 2011
  • In the present work, a new freeze protection method has been proposed for a natural circulation system of solar water heater. Though electrothermal wire is popularly used for the purpose, there are freezing troubles by wire cut-off and excessive electric power consumption. In the experimental device, hot water in a storage tank was circulated by a small pump and used to heat the outdoor pipes if the cold water pipe surface temperature falls lower than a set point. As a result, It was observed that there was no hot water waste while the solar water heating system operated without freeze and burst.

Design and Performance Verification of Compound CVTs with 2K-H I type Differential Gear

  • Kim Yeon-Su;Park Jae-Min;Choi Sang-Hoon
    • Journal of Mechanical Science and Technology
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    • 제20권6호
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    • pp.770-781
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    • 2006
  • This paper defined design constraints for the compound CVTs (continuously variable trans-missions) by combining power-circulation-mode CVTs and power-split-mode CVTs, which were proposed for connecting 2K-H I-type differential gear to V-belt-type CVU (Continuously Variable Unit). The design constraints are the necessary and sufficient conditions to avoid geometrical interferences among elements in the compound CVTs, and to guarantee smooth assembly between the power-circulation-mode CVT and power-split-mode CVT Two com-pound CVTs were designed and manufactured in accordance with the design constraints. With these compound CVTs, theoretical analysis and performance experiments were conducted. The results showed that the design constraints were valid and effective design method, and that the designed compound CVTs had the improved performance.

Inverse optimization problem solver on use of multi-layer neural networks

  • Wang, Qianyi;Aoyama, Tomoo;Nagashima, Umpei;Kang, Eui-Sung
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.88.5-88
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    • 2001
  • We propose a neural network solver for an inverse problem. The problem is that input data with complete teaching include defects and predict the defect value. The solver is constructed of a three layer neural network whose learning method is combined from BP and reconstruction learning. The input data for the defects are unknown; therefore, the circulation of an arithmetic progression replaces them; rightly, the learning procedure is not converged for the circulation data vut for the normal data. The learning is quitted after such a learning status id kept. Then, we search a minimum of the differences between teaching data and output of the circulation. Then, we search a minimum of the ...

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