• The Plant Pathology Journal
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• 제26권1호
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• pp.17-24
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• 2010

A logistic model for describing combined effects of both temperature and wetness period on appressorium formation was developed using laboratory data on percent appressorium formation of Colletotrichum acutatum. In addition, the possible use of the logistic model for forecasting infection risks was also evaluated as compared with a first-order linear model. A simplified equilibrium model for enzymatic reactions was applied to obtain a temperature function for asymptote parameter (A) of logistic model. For the position (B) and the rate (k) parameters, a reciprocal model was used to calculate the respective temperature functions. The nonlinear logistic model described successfully the response of appressorium formation to the combined effects of temperature and wetness period. Especially the temperature function for asymptote parameter A reflected the response of upper limit of appressorium formation to temperature, which showed the typical temperature response of enzymatic reactions in the cells. By having both temperature and wetness period as independent variables, the nonlinear logistic model can be used to determine the length of wetness periods required for certain levels of appressorium formation under different temperature conditions. The infection model derived from the nonlinear logistic model can be used to calculate infection risks using hourly temperature and wetness period data monitored by automated weather stations in the fields. Compared with the nonlinear infection model, the linear infection model always predicted a shorter wetness period for appressorium formation, and resulted in significantly under- and over-estimation of response at low and high temperatures, respectively.

• International Journal of Air-Conditioning and Refrigeration
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• 제8권1호
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• pp.14-28
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• 2000

The frequency response characteristics of a condenser were numerically studied for the control of refrigeration and air conditioning systems. The important parameters, such as the refrigerant flow rate, refrigerant temperature, air velocity, and air temperature at the condenser inlet, were analyzed. Superheated vapor, two phase, and subcooled liquid domain in condenser can be described by using the energy balance equation and the mass balance equation in refrigerant and tube wall, the basic equation for describing the dynamic characteristics of condenser can be derived. The transfer function for describing dynamic response of the condenser to disturbances can be obtained from using linearizations and Laplace transformations of the equation. From this transfer function, analytical investigation which affects the frequency responses of condenser has been made. Block diagrams were made based on the analytic transfer function; dynamic responses were evaluated in Bode diagrams on the frequency response. Through this study, it became possible that the information about the dynamic characteristics of air-cooled condenser is offered. The results may be used for determining the optimum design parameters in actual components and entire systems. Also, the mathematical models, frequency response may be used to help understanding, evaluate optimum design parameters, design control systems and determine on setting the best controller for the refrigeration and air-conditioning systems.

• 한국안전학회지
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• 제6권4호
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• pp.34-44
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• 1991

In this study, the general solution of heat balance equation including conductive heat loss were suggested and were determined the constants with the results of experiment in hot tunnel in order to derive the general equation for the response time and to investigate the response time index which represent the characteristics of response of sprinkler head in actual fires. Two types of test were considered, the plunge test, in which the air temperature is represented by a step function, and the ramp test, in which the air temperature increases at a constant rate. As a result, simple equations were derived, which can be predicted the response time for the ramp type fire with the rate of temperature rise and gas velocity, for the plunge type fire with temperature and gas velocity. Also other useful data, such as the effective temperature, time constant, response time index and conduction parameter were obtained.

• 자원ㆍ환경경제연구
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• 제25권2호
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• pp.141-178
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• 2016

본 논문은 실시간으로 측정되는 자동원격검침(AMR) 전력수요량을 사용하여 산업별 전력수요의 기온효과에 대한 특성과 패턴을 분석하였다. AMR 전력사용량의 시계열적 특징으로부터 장기 추세효과와 중기 기온효과 그리고 단기 특수일 효과로 구성되는 공적분 모형을 구축하고, 기온효과를 연속적인 기온반응함수를 통하여 분석하기 위하여 기온반응함수를 푸리에 플렉서블 폼(Fourier Flexible Form; FFF) 비선형 함수로 추정하였다. 추정 결과 도출된 기온반응함수와 기온효과를 통하여 기온효과가 뚜렷하게 나타나는 서비스업군과 기온효과가 미약하게 나타나는 제조업군으로 구분하였다. 그리고 기온효과가 뚜렷하게 나타나는 서비스업군을 기온반응함수의 추정치에 근거하여 여름피크 산업과 겨울피크 산업으로 구분하였다. 이러한 실증분석 결과는 산업별, 계절별 전력수요관리정책 수립에 정책적 기초를 제공한다. 또한 실시간으로 측정되는 AMR 전력수요량 분석이라는 점에서 시차의 발생없이 신속하게 전력수요관리에 반영될 수 있다는 의미가 있다.

• Journal of Microbiology and Biotechnology
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• 제17권4호
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• pp.644-649
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• 2007

Response surface model was developed for predicting the growth rates of Salmonella enterica sv. Typhimurium in tryptic soy broth (TSB) medium as a function of combined effects of temperature, pH, and NaCl. The TSB containing six different concentrations of NaCl (0, 2, 4, 6, 8, and 10%) was adjusted to an initial of six different pH levels (pH 4, 5, 6, 7, 8, 9, and 10) and incubated at 10 or $20^{\circ}C$. In all experimental variables, the primary growth curves were well $(r^2=0.900\;to\;0.996)$ fitted to a Gompertz equation to obtain growth rates. The secondary response surface model for natural logarithm transformations of growth rates as a function of combined effects of temperature, pH, and NaCl was obtained by SAS's general linear analysis. The predicted growth rates of the S. Typhimurium were generally decreased by basic (9, 10) or acidic (5, 6) pH levels or increase of NaCl concentrations (0-8%). Response surface model was identified as an appropriate secondary model for growth rates on the basis of coefficient determination $(r^2=0.960)$, mean square error (MSE=0.022), bias factor $(B_f=1.023)$, and accuracy factor $(A_f=1.164)$. Therefore, the developed secondary model proved reliable predictions of the combined effect of temperature, NaCl, and pH on growth rates for S. Typhimurium in TSB medium.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2001년도 전지기술심포지움
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• pp.145-161
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• 2001

Novel characterization of thermal properties of a battery has been introduced by defining its frequency-dependent thermal impedance function. Thermal impedance function can be approximated as a thermal impedance spectrum by analyzing experimental temperature transient which is related to the thermal impedance function through Laplace transformation. In order to obtain temperature transient, a process has been devised to generate external heat pulse with heating wire and to measure the response of battery. This process is used to study several commercial Li-ion batteries of cylindrical type. The thermal impedance measurements have been performed using potentionstat/galvanostate controlled digital signal processor, which is more commonly available than flow-meter usually applied for thermal property measurements. Thermal impedance spectra obtained for batteries produced by different manufactures are found to differ considerably. Comparison of spectra at different states of charge indicates independence of thermal impedance on charging state of battery. It is shown that thermal impedance spectrum can be used to obtain simultaneously thermal capacity and thermal conductivity of battery by non-linear complex least-square fit of the spectrum to thermal impedance model. Obtained data is used to simulate a response of the battery to internal heating during discharge. It is found that temperature inside the battery is by one-third larger that on its surface. This observation has to be considered to prevent damage by overheating.

• 설비공학논문집
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• 제8권3호
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• pp.386-396
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• 1996

The dynamic characteristics of a condenser are numerically studied for the control of air-conditioning systems. The important factors, such as the refrigerant flow rate and refrigerant temperature, air velocity and air temperature at the condenser inlet, are incorporated into the analysis. This study was focused on the analysis of dynamic responses by transfer function method in the condenser. Block diagrams were made through analytic transfer function, and dynamic responses are evaluated on Bode diagrams in the frequency response. These results may be used for determining an optimum design parameters in an actual component and total systems. Also, the mathematical models, frequency response and steady state response may be used to increase understanding, to obtain useful information for its commercialization, to evaluate the hardware and the optimum design parameters, the design control system and to determine the best controller setting for the refrigeration and air conditioning systems.

• 상하수도학회지
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• 제10권2호
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• pp.88-103
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• 1996

The objective of this study is to develop stochastic and deterministic models which could be used to synthesize water application time series. Adaptive models using mulitivariate ARIMA(Transfer Function Model) are developed for daily urban water use forecasting. The model considers several variables on which water demands is dependent. The dynamic response of water demands to several factors(e.g. weekday, average temperature, minimum temperature, maximum temperature, humidity, cloudiness, rainfall) are characterized in the model by transfer functions. Daily water use data of Kumi city in 1992 are employed for model parameter estimation. Meteorological data of Seonsan station are utilized to input variables because Kumi has no records about the meteorological factor data.To determine the main factors influencing water use, autocorrelogram and cross correlogram analysis are performed. Through the identification, parameter estimation, and diagnostic checking of tentative model, final transfer function models by each month are established. The simulation output by transfer function models are compared to a historical data and shows the good agreement.

• 한국환경복원기술학회지
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• 제2권1호
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• pp.66-71
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• 1999

Main concern is to figure out the growth response of Pinus densiflora to hydrologic conditions in the central Korea. Continuous measurements were carried out with six trees with dendrometers in the Chungbuk National University experimental forest (Wolak-san) during 1995~1996. Surrounding hydrological conditions reflected by the solar radiation, air temperature, precipitation, soil water were included in measurements. Their effects on the biological response of trees was investigated and expressed as response functions. With these response functions, tree growth model was developed. Soil water availability was more related to the tree growth than air temperature. Limited number of biological measurements with dendrometer could permit determination of dynamics of radial tree growth to the hydrological conditions. Tree growth model could be used to check and revise the statistical transfer function of dendrohydrology.

• 자원ㆍ환경경제연구
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• 제27권2호
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• pp.287-313
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• 2018

본 연구는 전력수요의 냉방 및 난방 수요를 측정하고 분석한다. 이를 위해 냉난방기온효과를 추정하고 이를 Chang et al. (2014)의 전력수요함수 모형에 적용하여 전력수요를 기본수요, 냉방수요 그리고 난방수요로 분해하였다. 1999년 1월부터 2016년 12월의 한국의 일반용과 주택용 전력수요를 분석한 결과, 난방수요의 증가율이 기본수요와 냉방수요의 증가율을 월등히 상회하였으며 특히 일반용에서 난방수요 증가가 두드러졌다. 평년기온으로 통제한 기온보정된 난방수요는 실현된 난방수요보다 상대적으로 '더' 증가하였고, 냉방수요는 반대로 기온보정된 수요가 실현된 수요에 비해서 '덜' 증가하였다. 본 논문은 전력수요 내의 냉방 및 난방수요를 측정할 뿐 아니라 경제주체들의 전력수요 변화 패턴을 확인했다는 점에 의의가 있으며, 추정 결과들은 향후 전력수요예측과 에너지수요관리 정책 수립에 도움을 줄 수 있을 것으로 기대된다.