• Journal of the Korean Society of Food Culture
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• v.12 no.4
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• pp.391-400
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• 1997

To provide basic information for the development of refrigerated convenience foods for Koreans, 492 house-wives residing in Seoul and Kyunggi Province were surveyed concerning satisfaction of buying precooked convenience foods, frequency of using them, preferred Korean dishes, and willingness to buy the convenience foods if they are developed. Statistical data analysis was completed using SAS package program. The satisfaction mean score of the marketed precooked convenience foods was 2.73 out of 5 and the housewives were least satisfied with feed additives and sanitation factors. The factors affecting satisfaction in purchasing were sanitation, taste, variety of type, nutrition, price, and food additives for side-dishes sold refrigerated or at room temperature, and taste, sanitation, variety of type, price, nutrition, and food additives for frozen prepared foods in order respectively. The frequency of using the precooked convenience foods was generally low but that of using the pickled dishes, Jokbal Soondae, and frozen prepared foods was relatively high. The answer of 'the thought that meals should be prepared in households' was the primary reason for avoiding using the precooked convenience foods and 'no time to cook' was the most frequent answer among the reasons for using them. Currently, the precooked convenience foods were used for snacks mainly, but the usages to be expected to increase were for lunchbox, main dishes, snacks, side dishes, special occasions foods, and leisure foods in order. Based on preference and buying priority, the dishes needed to be developed as refrigerated convenience foods among Korean dishes were identified. The result showed that 'preference' was not consistent with buying priority and the housewives perceived the factor of 'convenience' more importantly than 'preference' in purchasing the convenience foods.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.642-652
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• 2006

In order to understand the characteristics of surface ozone concentration and high $O_3$ concentration days, regional data from seven air quality monitoring stations which were operated by local governments were analyzed Regional characteristics of $O_3$ concentration were analyzed with the data of $O_3$ concentration and the characteristics of $O_3$ generation and weather conditions by the selection of the days in which the concentration was higher than 80 ppb. In the case of daily variation, the lowest $O_3$ concentration was shown in all regions from 7am to 8am and the highest around at 4 pm. The monthly variation of mean $O_3$ concentration and ${\Delta}O_3$ values revealed a reducing pattern in July and August following the peak in June, and again a gradual increasing trend in September and October. The result shows that the amount of ozone is dependent on photochemical reaction. The days of $O_3$ generated more than 80 ppb in the region of Gwangyang-bay were 544 days(1,760 hrs). The frequency of occurrence in the region revealed a strong pattern with the order of Samil-dong, Jinsang, and Gwangmu-dong stations in the Gwangyang region. However, Tein-dong, which is the nearest station to air pollution material generation source, showed the lowest frequency in the study area. Consequently, the meteorological parameters which can easily generate the high concentration of $O_3$ in the region of Gwangyang-bay are characterized as follows; atmospheric temperature which is higher than $19^{\circ}C$, relative humidity with the range of $60{\sim}85%$, the less average wind velocity than 5 m/s, cloud cover which is less than 5/10, and the more duration of sunshine than 8 hours.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.229-237
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• 2019

This study was conducted to estimate annual reference evapotranspiration (ET₀) for the agro-climatic zones for rice paddy fields in South Korea between 1980 and 2015. The daily ET₀ was estimated by applying the Penman-Monteith method to meteorological data from 61 weather stations provided by Korean Meteorological Administration (KMA). The average of annual ET₀ from 1980 to 2015 was 1334.1±33.89 mm. The ET₀ was the highest at the Southern Coastal Zone due to their higher air temperature and lower relative humidity. The ET₀ had significantly increased with 2.81 mm/yr for the whole zones over 36 years. However, the change rate of it was different among agro-climatic zones. The annual ET₀ highly increased in central zones and eastern coastal zones. In terms of correlation coefficient, the temporal change of the annual ET₀ was closely related to variations of four meteorological factors (i.e., mean, minimum temperatures, sunshine duration, and relative humidity). The results demonstrated that whole Korean agro-climatic zones have been undergoing a significant change in the annual ET₀ for the last 36 years. Understanding the spatial pattern and the long-term variation of the annual ET₀ associated with global warming would be useful to improve crop and water resource managements at each agro-climatic zone of South Korea.

• Journal of Bio-Environment Control
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• v.3 no.1
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• pp.1-9
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• 1994

Wind load or snow load, acting on agricultural structures is working more sensitive than any other load and therefore plays an important role in determination of design loads of agricultural structures. In this study, unit snow weight, greatest gust speed and depth of snow fall were analyzed and applied to determine the amount of frames. The unit snow weights were statistically classified and calculated in the basis of mean temperature and showed considerable differences between the unit snow weights at below and above -1$^{\circ}C$. Equations for estimating greatest gust speed with fastest wind speed were developed for inland and seaside districts. The calculated values from developed equations were little higher than those from the current equation in general. The difference between the depths of snow cover and snow fall, which shows the possibility of reduction of design loads under the adequate management. Design wind speed estimated by a modified equation suggested the amount of frames less than those by current one, and the depth of snow fall as a design snow depth suggested the amount of frames more than those of snow cover. Therefore, it is very important to select the adequate design values considering the characteristics of agricultural structures.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.476-482
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• 2006

An experimental study has been performed to investigate the characteristics of air-side heat transfer and friction of a fined tube heat exchanger under heating conditions. Air enthalpy calorimeter was used to obtain the performance evaluation and analysis of the fined tube heat exchanger. Eight finned tube heat exchangers with slit fin, louver fin, and plain fin were used. The air-side heat transfer coefficient was calculated by the log-mean-temperature-difference. Air-side heat transfer and friction were presented in terms of j factor and friction factor on Reynolds number. From the experimental result, it was found that the variations of air-side heat transfer and friction of fined tube heat exchanger with the change of the fin configuration, row number, fin pitch, and tube circuit were obtained. j factor and friction factor decreased with Reynolds number increased. The tube circuit affected the air-side heat transfer and friction. In the case of slit and louver fin, j factor of 1st row was higher than that of 2nd row. But, with increasing Re, j factor was reversed. The characteristics of j factor and friction factor of 2nd row heat exchanger were different according to the kind of fins.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1125-1131
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• 1996

Ca or Sr-doped $PrMnO_3$ were prepared for cathode material of solid oxide fuel cell. The characteristics such as the electrical conductivity and the cathodic overpotential were investigated as to doping contents. Also the reactivity with yttria stabilized zirconia of electrolyte, and the thermal expansion coefficient were studied. The prepared perovskite powder had the mean particle size of $2{\sim}5{\mu}m$, and the particle size and the surface area was out of relation to the doping content. When Ca doping amount of electrode material was 30mol%, the electrical conductivity was the highest value of $266S{\cdot}cm^{-1}$ at $1000^{\circ}C$, and also the polarization characteristics showed the best property. The reactivity between YSZ and Ca-doped $PrMnO_3$ at $1200^{\circ}C$ for 100hours was lower than that between YSZ and Sr-doped $PrMnO_3$. The thermal expansion coefficient of $Pr_{0.7}Ca_{0.3}MnO_3$ was $1.19{\times}10^{-5}K^{-1}$ in the temperature range of $300{\sim}1000^{\circ}C$, and this value was similar to that of YSZ, $1.15{\times}10^{-5}K^{-1}$.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.229-235
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• 1999

To identify the differences on plant growth and yield of two rice cultivars among direct water-seeding methods broadcasting on flooded paddy surface(BF), drilling on flooded paddy surface(DF), and puddled-soil drill seeding(PD) under markedly different weather condition between 1995 and 1996. The mean air temperature for duration from May to June, early growth stage of rice in 1995 was lower $1{\sim}3^{\circ}C$ than that in normal or 1996. In 1995 the respiratory consumption index during panicle formation stage and early ripening stage was higher than those of in 1996 or normal year. Number of seedling stand among the methods of direct seeding rice appeared slightly higher in order of BF>DF>PD. Properly in Nonganbyeo, the number of seedling stand was much low in 1995 compared with in 1996. The leaf area index and shoot dry weight at early growth stage of rice plant and culm length at mature in 1995 were larger in direct water seeding rice than those of machanical transplanting rice, but in 1996. Faster ripening speed and shorter ripening period of rice crop appeared in 1996 compared to in 1995. It was due to higher growing degree-days, sunshine hours and solar radiation during rice growing season in 1996. Dongjinbyeo rice showed higher yield than Nonganbyeo which had lower ripened grains especially in 1995.

• Korean Journal of Ecology and Environment
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• v.43 no.4
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• pp.492-502
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• 2010

The study objects were to analyze long-term and seasonal variations of nutrients (N, P), suspended solids, N:P ratios, algal chlorophyll, and trophic state along with general water quality parameters in four sampling sites including two intake tower sites supplying drinking water in Daechung Reservoir. For the analysis, we used water quality long-term data sampled during 1998~2007 by the Ministry of Environment, Korea. Interannual and seasonal trends in inflow and discharge near the intake tower facilities over the ten years were directly influenced by rainfall pattern. The distinct difference between wet year (2003) and dry year (2001) produced marked differences in water temperature, pH, dissolved oxygen, organic matter contents, nutrients, and these variables influenced algal biomass and trophic state. Values of TP varied depending on the year and locations sampled, but monthly mean TP always peaked during July~August when river inflow and precipitation were maxima. In contrast, TN varied little compared to TP, indicating lower influence by seasonal flow compared to phosphorus. The number of E. coli were highest in Site 2 (Chudong intake tower) and varied largely, whereas at other sites, the numbers were low and low variations. Contents of chlorophyll-${\alpha}$ (CHL), as an estimation of primary productivity, varied largely depending on the year and season. The maximum of CHL occurred at Muneu intake tower (S4) during 2006 when the precipitation and inflow were lowest. In contrast, another CHL peak was observed in Site 2 (Chudong intake tower) in 2006 when one of the largest typoons (Ewinia) occurred and river runoff were maximum. So the CHL maxima were associated with both wet year (high flow, high nutrient supply) and dry year (low flow, nutrient supply by littoral zone). Such conditions influenced trophic states, based on Trophic State Index of nutrients and CHL. Based on all analyses, we can provide some clues for management and protection strategies of two intake tower sites.

• Journal of the Korean Geographical Society
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• v.42 no.3 s.120
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• pp.355-367
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• 2007

As the global warming has been influenced on various sectors including agriculture, fisheries and health, it is essential to project more accurate future climate for an assessment of climate change impact and adaptation strategy. The purpose of this study is to examine the boundary changes in the subtropical climate region in South Korea using observed 30-year(1971-2000) data and projected 100-year data based on the IPCC SRES A1B emission scenario. We have selected Trewartha's climate classification among various climate classification, defining the subtropical climate region as the region with monthly mean temperature $10^{\circ}C$ or higher during 8-12 months. By observed data, the subtropical climate region was only limited in Jeju-do and the farmost southern coastal area(Busan, Tongyeong, Geoje, Yeosu, Wando, Mokpo) of South Korea. The future projected climate region for the period of 2071-2100 included have shown that subtropical climate region extended to most of stations except for the ares of Taebaeksan and Sobaeksan Mountains.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.821-832
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• 1998

This study investigates the prediction of daily water supply, which is a necessary for the efficient management of water distribution system. Fuzzy neuron, namely artificial intelligence, is a neural network into which fuzzy information is inputted and then processed. In this study, daily water supply was predicted through an adaptive learning method by which a membership function and fuzzy rules were adapted for daily water supply prediction. This study was investigated methods for predicting water supply based on data about the amount of water supplied to the city of Kwangju. For variables choice, four analyses of input data were conducted: correlation analysis, autocorrelation analysis, partial autocorrelation analysis, and cross-correlation analysis. Input variables were (a) the amount of water supplied (b) the mean temperature, and (c)the population of the area supplied with water. Variables were combined in an integrated model. Data of the amount of daily water supply only was modelled and its validity was verified in the case that the meteorological office of weather forecast is not always reliable. Proposed models include accidental cases such as a suspension of water supply. The maximum error rate between the estimation of the model and the actual measurement was 18.35% and the average error was lower than 2.36%. The model is expected to be a real-time estimation of the operational control of water works and water/drain pipes.