• 대한기계학회논문집
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• 제19권8호
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• pp.1999-2011
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• 1995

Computer simulation was conducted to study performance characteristics of air-cooled condenser of a double effect absorption heat pump with variations of saturation pressures and mass flow rates of the refrigerant ; volume flow rates, relative humidities and temperatures of the air The vertically installed condenser had the staggered tube array with continuous plate fins of wavy type. When the saturation pressure of the condenser was decreased from 760 torr to 20 torr, heat transfer rates and condensing rates of refrigerant were decreased. If excess refrigerant flows in the condenser, the pressure and saturation temperature of the condenser were increased which makes the refrigerating capacity of an absorption heat pump reduced.

• 대한기계학회논문집
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• 제19권8호
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• pp.2030-2038
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• 1995

In this study, three turbulent flame propagation models are compared using experimentally measured data of a 4 valves/cylinder spark-ignition engine. First two conventional models are B.K model and GESIM combustion model. The burning rates calculated from the two models are compared with the burning rates calculated from measured pressure data using the one-zone heat release analysis. GESIM combustion model predicts burning rates closer to the data acquired from the experiment in wide operating ranges than B-K model does. The third model is refined based on GESIM combustion model by including the effect of flame stretch, turbulent length scale band pass filter and a variable that considers flame size and the area of flame contacting the cylinder wall surface. The refined combustion model predicts burning rates closer to experimental results than GESIM combustion model does. Also, the refined combustion model predicts flame radius close to the experimental result measured by using optical fiber technique.

• 한국패류학회지
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• 제15권2호
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• pp.127-131
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• 1999

전북 곰소만에 서식하는 바지락의 생리적 리듬을 알아보기 위하여 24시간 동안 1시간 간격으로 산소소비율 및 여수율의 변화를 측정하였다. 바지락의 호흡율 및 여수율에 의한 생리적 리듬은 15$^{\circ}C$와 $25^{\circ}C$에서 두 가지 모두 24시간 동안 2번의 peak를 보이는데, 밤-만조시에 최대를 나타내었으며, 낮-간조시에 최소를 나타내어 조석에 의한 일주리듬 현상을 보였다. 24시간 동안 산소소비율 및 여수율의 변화는 수온별로 급격한 특수한 변화를 보이지 않았다.

• 한국음향학회지
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• 제19권8호
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• pp.47-53
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• 2000

수중에서 프로펠러에 의해 추진되는 추진체를 식별하기 위해 프로펠러의 추진력에 의하여 수중에 발생되는 cavitation의 비선형 음향학적 현상으로부터 발생되는 프로펠러의 shaft-rates와 blade-rates를 탐지하여 표적을 식별하기 위한 Maximum Likelihood Classifier를 유도하고, 시뮬레이션과 실험을 통한 검증을 수행하였고, 실제 해양에서 수집한 데이터에 대해 적용 가능함을 입증하였다.

• 보건행정학회지
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• 제9권2호
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• pp.40-54
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• 1999

The purpose of this study is to compare the health service utilization patterns between up and myun and to find the determinants of utilization. For this purpose. this study used different versions of utilization rates. such as crude utilization rates. utilization rates adjusted for population composition. and age-sex adjusted utilization rates. Data used in this analysis were the Community Health Interview Survey which was conducted by interviewing 741 households from August 31 to September 11, 1998 in HongCheon-Gun. KangWon-Do. The major findings of the analysis are summarized as follows: 1. There was a statistically significant difference in the level of health service utilization between up and myun. Depending upon the unit of analysis employed (those who were interviewed vs those who were sick). the difference between up and myun was reversed. 2. Determinants of health service utilization are analyzed using logistic regression. The result showed that predisposing factor influenced health service utilization in rural areas, while the enabling factor didn't.

• KDI Journal of Economic Policy
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• 제37권4호
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• pp.55-74
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• 2015

Using the Census on Establishments collected by Statistics Korea, we analyze how the patterns of job creation and destruction differ across counties (si-gun-gu). We measure aggregate employment changes due to establishment startups, expansions, contractions, and shutdowns for each county and quantify the role of such reallocations in explaining variation in employment growth across counties. Overall we find that both rates of net entry and job creation play an important role in explaining differences in net job creation rates across regions. Moreover, counties with high employment growth rates also tend to have high exit and job destruction rates, which suggests that an active process of job reallocation is a key source of regional employment growth.

• 한국환경과학회지
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• 제12권3호
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• pp.337-344
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• 2003

The photodegradation of pyrene, chrysene and benzo［a］pyrene, that were similar in structure among poly-cyclic aromatic hydrocarbons (PAMs), were investigated in water irradiated with a low-pressure mercury lamp (wavelength of 253.7 nm and UV output of 1.35 ${\times}$ 10$\^$-3/J/s). The effects of several factors (t-BuOH, HCO$_3$$\^$-/ and pH) on photodegradation of above three PAHs were also examined. The photodegradation rates of PAHs decreased with increasing the concentration of t-BuOH, but decreased little with increasing the concentration of HCO$_3$$\^$-/ under the concentrations used in this study. The photodegradation rates of PAHs decreased with increasing pH, but their change were greater in case of pH increase from acid to neutral and were little in case of pH increase from neutral to base. The photodegradation rates of PAMs fitted a first-order kinetic model and their photodegradation rates decreased in the following sequences: pyrene>chrysene>benzo[a]pyrene among the PAHs used.

• 전기학회논문지
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• 제62권12호
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• pp.1657-1660
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• 2013

Short-term load forecasting for Chusok and New Year's consecutive holidays is very difficult, due to the irregular characteristics compared with ordinary weekdays and insufficient holidays historical data. During consecutive holidays of New Year and Chusok, most of industries reduce their operation rates and their electrical load levels. The correlation between businesses' operation rates and their loads during consecutive holidays of New Year and Chusok is analysed and short-term load forecasting algorithm for consecutive holidays considering businesses' operation rates of industries is proposed. Test results show that the proposed method improves the accuracy of short-term load forecasting over fuzzy linear regression method.

• 대한가정학회지
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• 제37권12호
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• pp.169-177
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• 1999

This study has examined weight loss rates of Iyoceu, lyocell/cotton, cotton that were treated with cellulase under different concentration, time, temperature and pH. and compared physical properties changes of tensile strength, drape, moisture absorbency, shrinkage and dyeability. The notable results are summarized as follows: Lyocell was in need of pretreatment by NaOH in the side of weight loss, tensile strength and dyeability. Weight loss rates of cellulose fabrics by cellulase treatment were in the order of cotton > lyocell/cotton > lyocell at the same conditions. In case of lyocell and lyocell/cotton, weight loss rates showed up lower than cotton, while strength retention decreased, drape and strength flexibility were highly improved after cellulase treatment.

• Journal of applied mathematics & informatics
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• 제7권1호
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• pp.83-100
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• 2000

Many queueing systems such as M/M/s/K retrial queue with impatient customers, MAP/PH/1 retrial queue, retrial queue with two types of customers and MAP/M/$\infty$ queue can be modeled by a level dependent quasi-birth-death(LDQBD) process with linear transition rates of the form ${\lambda}_k$={\alpga}{+}{\beta}k$ at each level $\kappa$. The purpose of this paper is to propose an algorithm to find transient distributions for LDQBD processes with linear transition rates based on the adaptive uniformization technique introduced by van Moorsel and Sanders [11]. We apply the algorithm to some retrial queues and present numerical results.