• 한국수자원학회논문집
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• 제38권6호
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• pp.495-504
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• 2005

본 연구의 목적은 HSPF 모형과 Landsat 영상을 이용하여 토지피복 변화에 따른 유출의 변화를 분석하는 것이다. 토지피복도는 경안수위관측소 상류유역($258km^2$)에 대하여 10년 단위로 3개의 토지피복도(1980, 1990, 2000)를 준비하였다. HSPF의 수문학적 인자들의 보정에는 1999년부터 2000년의 경안수위관측소의 자료를 사용하였고, 검증에는 2001년과 2003년의 자료를 사용하였다. 토지피복도를 입력자료로 한 유출변화의 모의 결과, 20년 동안의 산림 감소 ($15.0\;km^2$)와 도심지 증가($19.3\;km^2$)에 따라 총유출량과 첨두유량이 증가하였다. 총유출량은 풍수년(2003, 1709.4mm)과 갈수년(2001, 871.2mm)의 강수조건에서 각각 $0.6\%,\;1.0\%$의 증가율을 보였다. 첨두유량은 2000년의 최대강우강도 241.3mm/hr 조건에서 $13.3\%$의 증가를 보였고, 성수기와 비성수기로 구분한 총유출량은 평수년(2000, 1257.3mm)인 2000년 강수조건에서 각각 $4.4\%$ 증가와 $8.1\%$ 감소로 가장 큰 변화를 보였다.

• 국제지역연구
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• 제20권1호
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• pp.105-125
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• 2016

일본은 21세기에 들어와서 경기침체와 디플레이션을 극복하기 위하여 확산적 화폐금융정책을 실시하였으며, 최근 아베정부는 무제한적으로 화폐공급을 증가시키고 있다. 그러나 이와 같은 정책의 효과는 아직 뚜렷이 나타나지 않고 있다. 본 연구의 목적은 2001년 이후 일본금융정책의 효과를 검증하는데 있다. 이를 위하여, 일본에서는 1990년 이후 버블형성과 붕괴이후 민간경제주체의 기대형성 과정이 변하고 있다는 사실에 기인하여, 기대가설을 내포하고 있는 거시모형을 설정하였다. 본 연구에서 사용된 거시모형은 통화량이 환율에 미치는 영향을 포함하였으며, 이를 IVM와 VAR를 이용하여 통계적으로 분석하였다. 통계분석 결과는 다음과 같다. 화폐금융정책의 효과는 2001.01-2015.03 기간에서 1985.01-1994.04.기간보다 낮아졌으며 효과가 미치는 기간도 짧아지고 있다. 이는 버블형성과 붕괴를 경험한 일본 민간경제주체가 더 이상 화폐금융정책의 효과를 믿지 않고 있기 때문인 것으로 판단된다. 통화량의 증가에도 불구하고 총수요는 영향을 받지 않고 있으며, 기대하지 못한 환율의 변화는 순수출을 증가시키고 있지만 통화 증가가 환율의 기대오차에 영향을 주지 못하고 있는 것으로 판단된다. 본 연구의 결과가 금융정책에서 의미하는 바는 중요하다고 할 수 있다. 일본의 버블형성과 붕괴, 그 후의 금융정책의 실패 등은 민간경제주체의 정책에 대한 신뢰를 변화시켰고, 화폐금융정책의 효과는 점차 낮아지고 있으며 불확실성은 커지고 있다. 확산적 화폐금융정책은 효과가 미흡할 경우 그 정책에 내재해 있는 위험성은 높아지므로 정책실시에 보다 신중한 결정이 요구된다. 또한 정부부채를 이용하는 재정정책을 배합하는 방향도 고려할 필요가 있다. 문제는 일본 정부부채 비율이 250%에 달한 것인데, 그렇다고 해서 재정정책을 사용하지 못한다는 근거는 없으므로, 이에 대한 또 다른 연구가 요구되는 시점이다.

• 대한건축학회논문집:구조계
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• 제34권11호
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• pp.73-79
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• 2018

In this study, for the prediction of energy consumption in the ventilator, one of the components of the air conditioning system, the predicted results were analyzed and accurate by the change in the number of neurons and inputs. The input variables of the prediction model for the energy volume of the fan were the supply air flow rate, the exhaust air flow rate, and the output value was the energy consumption of the fan. A predictive model has been developed to study with the Levenbarg-Marquardt algorithm through 8760 sets of one-minute resolution. Comparison of actual energy use and forecast results showed a margin of error of less than 1% in all cases and utilization time of less than 3% with very high predictability. MBE was distributed with a learning period of 1.7% to 2.95% and a service period of 2.26% to 4.48% respectively, and the distribution rate of ${\pm}10%$ indicated by ASHRAE Guidelines 14 was high.8.

• 대한설비공학회지:설비저널
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• 제17권6호
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• pp.696-707
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• 1988

This study simulates a typical solar system using the transient simulation program TRNSYS, and calculates the maximum cooling load of the model room of $50m^2$. In this study, energy rate control method is used in calculating a maximum cooling load. On the ground of the maximum cooling load of the model room, the variables that have an effect on the solar collection performance of the solar system are made a selection. Also in this study the trend of the solar collection performance is shown as the variables change. The results show that the variables which have an effect on the collection performance are collector area, collector mass flow rate, collector slope and the volume of storage tank, and the optimal value of Ac/Vt is not constant but varies as the collector area and the collector mass flow rate. Also the results show that for cooling system the optimal value of the collector slope is latitude minus $15^{\circ}$ during the seasonal operations, and twenty percent of the maximum cooling load is saved with the aid of the solar energy.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.29-32
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• 2004

This work was devoted to an investigation of etching mechanisms for $(Ba,Sr)TiO_3$ (BST) thin films in inductively coupled $CF_4/Ar$ plasma. We have found that an increase of the Ar content in $CF_4/Ar$ plasma causes non-monotonic behavior of BST etch rate, which reaches a maximum value of 40 nm/min at 80% Ar. Langmuir probe measurements show a weak sensitivity of both electron temperature and electron density to the change of $CF_5/Ar$ mixing ratio. O-D model for plasma chemistry gave monotonic changes of both volume densities and fluxes for active species responsible for the etching process. The analysis of surface kinetics confirms the possibility of non-monotonic etch rate behavior due to the concurrence of physical and chemical pathways in ion-assisted chemical reaction.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 고액공존금속의 성형기술 심포지엄(III) SYMPOSIUM ON SEMISOLID FORMING TECHNOLOGY(III)
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• pp.15-32
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• 1999

A relationship between stress and stain is very important to design a die to avoid defects of products during semi-solid forming process. Since the liquid will be of eutectic composition in alloys liquid segregation will result in significant or undesirable situation. The materials used in this experiment are A 357. A390, Al2024 alloys that is fabricated by the electro-magnetic stirring process from Pechiney in France. The compression test was performed by induction heating equipment and MTS. In order to prevent the liquid segregation these measured temperature would be useful to control of strain rate during compression test. The liquid segregation is controlled as change of the strain rate and solid fraction during the compression process, The characteristics of flow between solid and liquid phase considering liquid segregation is examined through the above experiments. In the case of medium and high volume fractions of solid the distribution of strain rate is calculated by using compression test data of semi-solid materials (SSM). The thixoforming experiments with the designed die are carried out successfully. The die filling patterns of SSM for variation of die temperature and pressing force have been investigated. The hardness of the thixoformed scroll products is evaluated in terms of the microstructure for each position.

• 펄프종이기술
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• 제35권5호
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• pp.26-36
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• 2003

The wet-end dynamics of a paper mill was analyzed to characterize its dynamic behavior during the grade change of paper. The model representing the wet-end section is developed based on the mass balance relationships written for the simplified wet-end white water network. From the linearization of dynamic model, higher-order Laplace transfer functions were obtained followed by the reduction procedure to give simple lower-order models in the form of 1$^{st}$-order or 2$^{nd}$ -order plus dead times. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid flow rate on the major controlled variables were analyzed by numerical simulations. The simple dynamic model developed in the present study can be effectively used in the operation and control of paper mills.s.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.328-336
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• 2021

Objective: The purpose of this study was to investigate the effect of cervical range of motion training on the change in respiratory function growth rate at the group and individual level in stroke patients and stroke patients with tracheostomy tube. Design: A Multilevel Growth Model Methods: 8 general stroke patients and 6 stroke patients who had a tracheostomy tube inserted were subjected to cervical range of motion training 3 times a week for 4 weeks. Force vital capacity (FVC), Forced expiratory volume in the first second (FEV1), Forced expiration ratio (FEV1/FVC) and Manual assist peak cough flow (MPCF) were measured. Data were analyzed using descriptive statistics and multilevel analysis with HLM 8.0. Results: A significant difference was found in the respiratory function analysis growth rate of the entire group (p<0.05), and two groups were added to the research model. The linear growth rate of respiratory function in patients with general stroke increased with the exception of FEV1/FVC (p<0.05). Stroke patients with tracheostomy tube showed a decreasing pattern except for FVC. In particular, MPCF showed a significantly decreased result (p<0.05). Conclusions: This study found that the maintenance of improved respiratory function in stroke patients with tracheostomy tube decreased over time. However, cervical range of motion training is still a useful method for respiratory function in general stroke patients and stroke patients with tracheostomy tube.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2003년도 추계학술발표논문집
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• pp.306-330
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• 2003

The wet-end dynamics of a paper mill was analyzed to characterize its dynamic behavior during the grade change. The model representing the wet-end section is developed based on the mass balance relationships written for the simplified wet-end white water network. From the linearization of the dynamic model, higher-order Laplace transfer functions were obtained followed by the reduction procedure to give simple lower-order models in the form of $1^{st}$-order or $2^{nd}$-order plus dead times. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid flow rate on the major controlled variables were analyzed by numerical simulations. The simple dynamic model developed in the present study can be effectively used in the operation and control.

• 열처리공학회지
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• 제4권3호
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• pp.39-46
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• 1991

The effects of austenitizing temperatures and times and cooling rate on the characteristics of continuous air cooling have been investigated for 0.3%C-Mn steels microalloyed with vanadium. Transformation start temperatures have been found to be measured from temperature-time curve directly obtained with continuous air cooling and to decrease with increasing austenitizing temperature, cooling rate and Mn contents. The coarsening behavior of austenite grain size has been measured to abnormally grow at $1050^{\circ}C$ and rapidly grow at $1200^{\circ}C$. It has been found that the volume fraction of pearlite was linealy proportional to the reciprocal square root of austenite grain size. The hardness has been measured to increase with increasing cooling rate up to $250^{\circ}C/min.$ and to remain relatively unchanged in the range of $250{\sim}400^{\circ}C/min.$ showing that hardness valves for steel with a higher Mn content increase more than those for steel with a lower Mn content. The impact property has been found to decrease with increasing of austenite grain size but does not linealy change with the reciprocal square root of austenite grain size.