• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.1
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• pp.19-26
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• 2017

Surface air temperature ($T_{air}$) is a key variable for the meteorology and climatology, and is a fundamental factor of the terrestrial ecosystem functions. Satellite remote sensing from the Moderate Resolution Imaging Spectroradiometer (MODIS) provides an opportunity to monitor the $T_{air}$. However, the several problems such as frequent cloud cover and mountainous region can result in substantial retrieval error and signal loss in MODIS $T_{air}$. In this study, satellite-based $T_{air}$ was estimated under both clear and cloudy sky conditions in Gangwon Province using Aqua MODIS07 temperature profile product (MYD07_L2) and GCOM-W1 Advanced Microwave Scanning Radiometer 2 (AMSR2) brightness temperature ($T_b$) at 37 GHz frequency, and was compared with the measurements from the Automated Mountain Meteorology Stations (AMOS). The application of ambient temperature lapse rate was performed to improve the retrieval accuracy in mountainous region, which showed the improvement of estimation accuracy approximately 4% of RMSE. A simple pixel-wise regression method combining synergetic information from MYD07_L2 $T_{air}$ and AMSR2 $T_b$ was applied to estimate surface $T_{air}$ for all sky conditions. The $T_{air}$ retrievals showed favorable agreement in comparison with AMOS data (r=0.80, RMSE=7.9K), though the underestimation was appeared in winter season. Substantial $T_{air}$ retrievals were estimated 61.4% (n=2,657) for cloudy sky conditions. The results presented in this study indicate that the satellite remote sensing can produce the surface $T_{air}$ at the complex mountainous region for all sky conditions.

• Journal of Korea Water Resources Association
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• v.53 no.9
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• pp.701-715
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• 2020

This study compared several reference evapotranspiration estimated using eight methods such as FAO-56 Penman-Monteith (FAO PM), Hamon, Hansen, Hargreaves-Samani, Jensen-Haise, Makkink, Priestley-Taylor, and Thornthwaite. In addition, by analyzing the monthly deviations of the results by the FAO PM and the remaining seven methods, monthly optimized correction coefficients were derived and the improvement effect was evaluated. These methods were applied to 73 automated synoptic observation system (ASOS) stations of the Korea Meteorological Administration, where the climatological data are available at least 20 years. As a result of evaluating the reference evapotranspiration by applying the default coefficients of each method, a large fluctuation happened depending on the method, and the Hansen method was relatively similar to FAO PM. However, the Hamon and Jensen-Haise methods showed more large values than other methods in summer, and the deviation from FAO PM method was also large significantly. When comparing based on the region, the comparison with FAO PM method provided that the reference evapotranspiration estimated by other methods was overestimated in most regions except for eastern coastal areas. Based on the deviation from the FAO PM method, the monthly correction coefficients were derived for each station. The monthly deviation average that ranged from -46 mm to +88 mm before correction was improved to -11 mm to +1 mm after correction, and the annual average deviation was also significantly reduced by correction from -393 mm to +354 mm (before correction) to -33 mm to +9 mm (after correction). In particular, Hamon, Hargreaves-Samani, and Thornthwaite methods using only temperature data also produced results that were not significantly different from FAO PM after correction. It can be also useful for forecasting long-term reference evapotranspiration using temperature data in climate change scenarios or predicting evapotranspiration using monthly or seasonal temperature forecasted values.

• Journal of the Korean Geographical Society
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• v.28 no.2
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• pp.112-122
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• 1993

Since more than 50${\%}$ of annual precipitation in Korea falls during Changma, the rainy season of early summer, and Late Changma, the rainy season of late summer, forcasting the onset days Changmas, and the amount related rainfalls would be necessary not only for agriculture but also for flood-control. In this study the authors attempted to build a prediction model for the forecast of the onset date of Changmas. The onset data of each Changma was derived out of daily rainfall data of 47 stations for 30 years(1961~1990) and weather maps over East Asia. Each station represent any of the 47 districts of local forecast under the Korea Meteorological Administration. The average onset dates of Changma during the period was from 21 through 26 June. The dates show a tendency to be delayed in El Ni${\~{n}}o years while they come earlier than the average in La Nina years. In 1982, the year of El Ni${\~{n}}o, the date was 9 Julu, two weeks late compared with the average. The relation of sea surface temperature(SST) over Pacific and Northern hemispheric 500mb height to the Changma onset dates was analyzed for the prediction model by polynomial regression. The onset date of Changma over Korea was correlated with SST in May(SST${_(5)}{^\circ}$C) of the district (8${^\circ}$~12${^\circ}S, 136${^\circ}~148${^\circ}W)of equatirial middle Pacific and the 500mb height in March (MB${_(3)}$"\;"m)over the district of the notrhern Hudson Bay. The relation between this two elements can be expressed by the regression: Onset=5.888SST${_5}"\;"+"\;"0.047MB${_(3)}$"\;"-251.241. This equation explains 77${\%}$ of variances at the 0.01${\%}$ singificance level. The onset dates of Late Changma come in accordance with the degeneration of the Subtro-pical High over northern Pacific. They were 18 August in average for the period showing positive correlation(r=0.71) with SST in May(SST)${_(i5)}{^\circ}$C) over district of IndiaN Ocean near west coast of Australia (24${^\circ}$~32${^\circ}$S, 104${^\circ}$~112${^\circ}$E), but negativ e with SST in May(SST${_(p5)}{^\circ}$ over district (12${^\circ}$~20${^\circ}$S,"\;"136${^\circ}$~148${^\circ}$W)of equatorial mid Pacific (r=-0.70) and with the 500mb height over district of northwestern Siberia (r=-0.62). The prediction model for Late Changma can be expressed by the regression: Onset=706.314-0.080 MB-3.972SST${_(p5)}+3.896 SST${_(i5)}, which explains 64${\%}$ of variances at the 0.01${\%}$ singificance level.

• The Korean Journal of Ecology
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• v.27 no.6 s.122
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• pp.383-390
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• 2004

This study was conducted in three sites, Si-Hwa Lake, Dongman and Seoman island and Janguyeop island, from march, 1999 to september, 2002. The behaviors of pre-breeding season, territorial behaviors, reproductive ecology, foraging sites and behaviors, and the competition of reproduction and foods between intraspecific or interspecific of Eurasian Oystercatcher (Haematopus ostralegus) were observed in each studying sites. The breeding of Eurasian Oystercatcher started on the middle of April in Si-Hwa Lake and on the middle of May in Dongman and Seoman island and Janguyeop island. For intension of pair bond on pre-breeding season, Eurasian Oystercatcher foraged with pair and behaved male-female chasing flight behavior. The pair foraged with male and female before copulation. If other pairs and individuals approached in feeding site of pair, this pair attacked them with piping calling and intruder chasing flight. If continuos serial behaviors were not observed, the discrimination of male-female chasing flight and intruder chasing flight was difficult. Territorial behaviors classified four types; butterfly flight, calling behavior, chasing behavior, fight behavior. The important foraging sites in Si-Hwa Lake are the land place in Daeboo island, tidal flat of Bangameori, tidal flat a front of a stationary net for catching fishes and tidal flat a front of a view station for bird watching. Eurasian Oystercatcher foraged at tidal flat on low water of the tide and foraged at feeding sites near island on flood tide in Dongman and Seoman island. Eurasian Oystercater in Janguyeop island usually foraged feeding sites near island, because water level was not different between low water of the tide and flood tide. Eurasian Oystercatcher competed on foods of intraspecific and interspecific. They chased for taking foods by force in feeding sites and drove out intruders in feeding sites. The foods interspecific competition happened with Black-tailed Gull (Larus crassirostris). Eurasian Oystercatcher was robbed of foods and attacked by Black-tailed Gull. The individual of food competition with Black-tailed Gull was low foods intake rate comparison with other feeding sites and this individual flied out other feeding sites.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.16-25
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• 2009

Cauliflower mushroom (Sparassis crispa) is recently recognized as a new edible and/or medicinal mushroom cultivated with conifers. By the way, the mushroom is notorious as a brown-rot fungus that causes a buttrot of larch. So, there should be a careful consideration to apply the mushroom cultivation in coniferous stand. This study was conducted to clarify the seriousness of heartwood decay on conifers such as larch by cauliflower mushroom with surveying the mushroom producing environment and to examine whether the cultivation of cauliflower mushroom produce any problem in conifer stands or not. The mushroom occurred in various coniferous stands such as Larix kaempferi, Pinus koraiensis, P. densiflora and Abies holophylla on fertile soils with adequate moisture. Soil texture of the mushroom producing site was comparatively fine compared to general forest soils; sandy loam, loam and silty loam. Soil pH ranged from 4.6 to 5.2, and organic matter contents were 4~11%, which showed relatively wide range. We could find S. crispa by a DNA technique from the wood that seemed to have no heartwood decay by naked eyes. The damaged wood showed 30% higher moisture contents than that of sound wood, while the compressive strength was 30% lowered down compared to that of sound wood. The fungus may invade conifers through the scars occurred on roots or stems, in this case spore dispersion of the mushroom takes a great role. Thus, we concluded that forest tending activities need to be applied with considering the invasion of S. crispa, and cultivation of cauliflower mushroom in forest should be attempted very carefully. By the way, we also infer that conifer stands can be nurtured without heartwood decay by S. crispa if the stand be managed in good aeration conditions by proper silvicultural practices such as sanitary thinning.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.288-292
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• 2008

This study was conducted to identify the effects of irrigation amount to produce high quality melon fruit in fertigation culture. Irrigation amount of during fruit harvesting period was doubled at the low irrigation point ($(-45{\sim}50\;kPa$) treatment as 115 mm as than that of the high irrigation point ($-20{\sim}25\;kPa$) treatment. The plant growth rates such as stem length, leaf weight and plant height were a little diminished at the low irrigation point ($-45{\sim}50\;kPa$) than those of the other treatments. Internode length was however not affected by irrigation amount. Fruit weight was lighter at the low irrigation point ($-45{\sim}50\;kPa$) than that of at the high irrigation point and fruit height was shorter, but fruit diameter was not affected by irrigation amount. Fruit soluble solid was $0.9^{\circ}Bx$ higher at the low irrigation point ($-45{\sim}50\;kPa$) than at the high irrigation point ($-20{\sim}25\;kPa$) and net index was higher. Total marketable yield was highest by 3,937 kg/10a at the high irrigation point ($-20{\sim}25\;kPa$), but the excellent marketable yield was highest by 2,531 kg/10a at the low irrigation point ($-45{\sim}50\;kPa$). Inorganic contents of the soil N, K, Ca and Mg were not affected by irrigation amount. It was therefore thought that optimum irrigation point to produce high quality melon fruit by fertigation culture was $-45{\sim}50\;kPa$ at ripening stage.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.336-341
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• 2008

The objective of this research was to investigate the suitable cultivar for organic strawberry (Fragaria ananassa Duch.) cultivation in Korea. The six strawberry cultivars which were bred and commonly cultivated in Korea as forcing and semi-forcing culture were tested in this experiment. To achieve the objectives, various characteristics of these cultivars were investigated for two consecutive years such as growth habit, yield, fruit quality and occurrence rate of disease/pest. As results of this research, the total yield of 'Seolhyang' was the highest among cultivars tested in both forcing and semi-forcing cultivation. The average of soluble solid contents (SSC) in 'Seolhyang' was $12.0^{\circ}Bx$ that is lower than other cultivars and especially below $10^{\circ}Bx$ after March (high temperature period). But there was not much difference in SSC among 6 cultivars until the end of February. The average of hardness in 'Seolhyang' was 279g/${\phi}5\;mm$ which was a little higher than that of 'Akihime'. Titration acidity (TA) in 'Maehyang' was 0.69% which was the highest value among 6 cultivars. Total fresh/root weight of 'Seonhong' and leaf area of 'Seolhyang' were significant among other cultivars' ones in forcing culture. Growth habits (fresh weight, root weight, leaf area, etc.) showed no significant difference among cultivars in semi-forcing culture. The lowest occurrence rate for powdery mildew and aphids was found in 'Seolhyang', but gray mold was severer than other cultivars. The density of two spider mites was the lowest in 'Redpearl'. We have concluded that 'Seolhyang' is the most suitable cultivar for organic strawberry cultivation by the result of yield, fruit quality and resistance of disease/pest.

• Journal of Life Science
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• v.16 no.1
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• pp.22-29
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• 2006

Effect of microbial products made of Bacillus stearothermophilus DL-3 on growth of chickens and pigs was investigated. Two types of microbial product were made in this study. One is the microbial product made of culture broth of B. stearothemophilus DL-3 and rice bran which named as the microbial product A. The other is the microbial product made of culture broth of B. stearothermophilus DL-3, apple pomace, soybean pomace and rice bran which named as the microbial product B. Chickens were divided into three groups and each group was fed with $100\%$ general feed, $90\%$ general feed supplemented with $10\%$ microbial product A or $90\%$ general feed supplemented with $10\%$ microbial product B. The average chicken weight of each group was $41.1{\pm}2.5g,\;41.6{\pm}3.2g\;and\;42.3{\pm}2.9g$ and those after 28 days was $547.7{\pm}91.7g,\;560.1{\pm}17.2g\;and\;562.2{\pm}32.5g$, respectively. The average weight gain for each group was 506.6 g, 518.6 g and 519.9 g, respectively, and weight increases of groups fed with $90\%$ general feeder and $10\%$ microbial product A and B were $2.4\%\;and\;2.6\%$ higher than the group fed with $100\%$ general feed. Pigs were also divided into three groups and each group was fed like chickens. The average weight of each group was $9.3{\pm}1.0kg,\;9.4{\pm}1.1kg\;and\;9.6{\pm}1.0kg$ and those after 37 days was $19.3{\pm}4.1kg,\;20.2{\pm}3.9kg\;and\;20.8{\pm}4.2kg$, respectively. The average Weight gain for each group was 10.65 kg, 10.82 kg and 11.20 kg, respectively, and weight increases of groups fed with $90\%$ general feeder and $10\%$ microbial product A and B were $1.6\%$ and $5.2\%$ higher than the group fed with $100\%$ general feed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.367-372
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• 2002

In order to utilize safflower seed effectively as a food material, it was processed at the conditions including roasting temperature/time of 170$\^{C}$/10 min to 210$\^{C}$/30 min, ethanol concentration of 0 to 100% (V/V) and enzyme hydrolysis with $\alpha$-amylase, $\beta$-amylase, amyloglucosidase and cellulase. Safflower seed extracts had the highest soluble solid content at the condition of 60% ethanol concentration, roasting at 190$\^{C}$ for 20 min and hydrolysis with amyloglucosidase. Total phenolic compounds increased with the ethanol concentration, showing the highest at the condition of 80% ethanol, roasting at 170$\^{C}$ for 30 min and hydrolysis with amyloglucosidase. High level total flavonoid was observed at the condition of 80% ethanol, roasting at 210$\^{C}$ for 30 min and hydrolysis with amyloglucosidase. Safflower seed had sucrose as major free sugar as well as xylose and arabinose as minor free sugars. Organic acids in safflower seed included oxalic, citric, magic and fumaric acid. Serotonin I (N-[2-(5-hydroxy-1H-indo-1-3-yl)ethyl]ftrulamide) and serotonin II (N-[2-(5-hydroxy-1H-indol-3yl)ethyl]-p-coumaramide) as antioxidant compounds increased with ethanol concentration, showing the highest revel at 60% ethanol. Acacetin content increased with temperature and roasting time, with a maximum of 69.47 mg% at 210$\^{C}$ for 30 min.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.5
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• pp.258-270
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• 2014

In this paper, we investigate channel capacity of two kinds of uplink OFDMA (Orthogonal Frequency Division Multiple Access) schemes, i.e. ZCZ (Zero Correlation Zone) code time-spread OFDMA and sparse SC-FDMA (Single Carrier Frequency Division Mmultiple Access) robust to access timing offset (TO) among multiple users. In order to reflect the practical condition, we consider not only access TO among multiple users but also peak to average power ratio (PAPR) which is one of hot issues of uplink OFDMA. In the case with access TO among multiple users, the amplified signal of users by power control might affect a severe interference to signals of other users. Meanwhile, amplified signal by considering distance between user and base station might be distorted due to the limit of amplifier and thus the performance might degrade. In order to achieve the maximum channel capacity, we investigate the combinations of transmit power so called ASF (adaptive scaling factor) by numerical simulations. We check that the channel capacity of the case with ASF increases compared to the case with considering only distance i.e. ASF=1. From the simulation results, In the case of high signal to noise ratio (SNR), ZCZ code time-spread OFDMA achieves higher channel capacity compared to sparse block SC-FDMA. On the other hand, in the case of low SNR, the sparse block SC-FDMA achieves better performance compared to ZCZ time-spread OFDMA.