• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.461-470
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• 2019

This study was carried out to quantify the drought stress in grafted watermelon seedlings non-destructively by using chlorophyll fluorescence (CF) imaging technique rather than the visual judgment. Six-day old watermelon seedlings were grown under uniform irrigation for 3 days, and then given drought stress. Afterward, the sensor for the measurement of water content in plug tray cell unit was used to classify the drought-stress level into nine groups from D1 (53.0%, sufficient moisture state) to D9 (15.7%, extremely dry stress), and the 16 CF parameters were measured. In addition, re-irrigation was performed on the drought stressed seedlings(D5 - D9) to determine the growth and photosynthesis recovery level, which was not confirmed by visual judgment. The kinetic curve patterns of CF in three different drought stressed seedling groups were found to be different for the early detection of drought stress. All the 16 CF parameters decreased continuously with exposure to drought stress and drastically decreased from D5 (32.1%) where the visual judgment was possible. The fluorescence decline ratio (Rfd_Lss) started to decrease from the initial drought stress level (D5 - D6), and the Maximum PSII quantum yield (Fv/Fm) was significantly decreased in the later extreme drought stress range (D7 - D9) by re-irrigation recovery test. Thus, Rfd_Lss and Fv/Fm parameters were finally selected as potent indicators of growth and photosynthesis recovery in the initial and later stages of drought stress. Also, to the differences in the numerical values of the individual chlorophyll fluorescence parameters, the drought stress level was intuitively confirmed through the image. These results indicate that Rfd and Fv/Fm can be considered as potential CF parameters for the detection of low and extremely high drought stress, respectively. Furthermore, Fv/Fm can be considered as the best CF parameters for recovery at re-irrigation.

• Journal of Life Science
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• v.29 no.6
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• pp.653-661
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• 2019

The first small interfering RNA (siRNA) therapeutics have recently been approved by the Food and Drug Administration in the U.S., and the demand for a new RNA therapeutics bioanalysis method-which is essential for pharmacokinetics, including the absorption, distribution, metabolism, and excretion of siRNA therapeutics-is rapidly increasing. The stem-loop real-time qPCR (RT-qPCR) assay is a useful molecular technique for the identification and quantification of small RNA (e.g., micro RNA and siRNA) and can be applied for the bioanalysis of siRNA therapeutics. When the anti-HPV E6/E7 siRNA therapeutic was used in preclinical trials, the established stem-loop RT-qPCR assay was validated. The limit of detection was sensitive up to 10 fM and the lower limit of quantification up to 100 fM. In fact, the reliability of the established test method was further validated in three intra assays. Here, the correlation coefficient of $R^2$>0.99, the slope of -3.10 ~ -3.40, and the recovery rate within ${\pm}20%$ of the siRNA standard curve confirm its excellent robustness. Finally, the circulation profiles of siRNAs were demonstrated in rat serum, and the pharmacokinetic properties of the anti-HPV E6/E7 siRNA therapeutic were characterized using a stem-loop RT-qPCR assay. Therefore, the stemloop RT-qPCR assay enables accurate, precise, and sensitive siRNA duplex quantification and is suitable for the quantification of small RNA therapeutics using small volumes of biological samples.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.339-348
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• 2019

The purpose of this study was to investigate the effect of carotid artery ultrasound Respectively. The carotid intima-media thickness is known to have a significant correlation with cardiovascular disease and cerebrovascular disease. We investigated the relationship between carotid intima - media thickness, body mass index, waist circumference, the blood lipid value, fasting blood glucose, glycated hemoglobin, and blood pressure using carotid artery ultrasound. The carotid artery ultrasound was considered to be abnormality of IMT thickness over 0.8 mm and the presence or absence of atherosclerotic plaque was evaluated. Serological tests were used to compare the geologic value, fasting blood glucose level, and glycated hemoglobin. As a result, waist circumference (=.022), low density cholesterol (=.004), fasting blood glucose level (.019), and glycemic index (.002) were analyzed as predictors of atherosclerosis. In the ROC curve analysis, sensitivity was 87.80% (95% CI: 73.8-95.9), specificity was 41.67% (95% CI: 30.2-53.9), sensitivity was 78.05% (95% CI: 62.4-89.4) in low density lipoprotein, Specificity was 50.00% (95% CI: 38.0-62.0), sensitivity was 73.11% (95% CI: 57.1-85.8), specificity was 61.11 (95% CI: 48.9-72.4) and sensitivity was 82.93%-91.8) and a specificity of 43.06% (31.4-55.3). In logistic regression analysis, the risk of atherosclerosis was 0.248 times at waist circumference (WC)> 76 cm, 3.475 times at low-density lipoprotein (LDL-C) ${\geq}124mg/dL$, 0.618 at HbA1c> 5.4% It appeared as a times. We suggest that prospective study of carotid artery ultrasound should be performed for the effective prevention of cardiovascular diseases.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.419-431
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• 2021

In Seoul, it has been confirmed that the duration of rainfall is shortened and the frequency and intensity of heavy rains are increasing with a changing climate. In addition, due to high population density and urbanization in most areas, floods frequently occur in flood-prone areas for the increase in impermeable areas. Furthermore, the Seoul City is pursuing various projects such as structural and non-structural measures to resolve flood-prone areas. A disaster prevention performance target was set in consideration of the climate change impact of future precipitation, and this study conducted to reduce the overall flood damage in Seoul for the long-term. In this study, 29 GCMs with RCP4.5 and RCP8.5 scenarios were used for spatial and temporal disaggregation, and we also considered for 3 research periods, which is short-term (2006-2040, P1), mid-term (2041-2070, P2), and long-term (2071-2100, P3), respectively. For spatial downscaling, daily data of GCM was processed through Quantile Mapping based on the rainfall of the Seoul station managed by the Korea Meteorological Administration and for temporal downscaling, daily data were downscaled to hourly data through k-nearest neighbor resampling and nonparametric temporal detailing techniques using genetic algorithms. Through temporal downscaling, 100 detailed scenarios were calculated for each GCM scenario, and the IDF curve was calculated based on a total of 2,900 detailed scenarios, and by averaging this, the change in the future extreme rainfall was calculated. As a result, it was confirmed that the probability of rainfall for a duration of 100 years and a duration of 1 hour increased by 8 to 16% in the RCP4.5 scenario, and increased by 7 to 26% in the RCP8.5 scenario. Based on the results of this study, the amount of rainfall designed to prepare for future climate change in Seoul was estimated and if can be used to establish purpose-wise water related disaster prevention policies.

• Korean Journal of Environment and Ecology
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• v.35 no.3
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• pp.223-236
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• 2021

This study aims to provide basic data for the systematic conservation and efficient management of forest ecosystems by analyzing changes in understory vegetation of temperate broad-leaved deciduous forests. One-hectare permanent survey plot, consisting of 100 subplots sized 10 × 10 meters, was installed in Gwangneung forest in Pocheon, Gyeonggi-do in 2003. The state of stands and the understory vegetation in the permanent survey plot were examined at a 5-year interval from 2003 to 2018. The vascular plants found in the survey area were 56 families, 128 genera, 176 species, 18 variants, 4 varieties, and 1 subspecies, for a total of 199 taxa. The number of species in both the shrub layer and the herbaceous layer showed a tendency to decrease with time. The MRPP-tests showed a significantly differing species composition of the shrub layer in all years except 2008-2013, whereas significant differences were found in all years concerning the herbaceous layer. As for the average importance value, Euonymus oxyphyllus (18.23%), Acer pseudosieboldianum (16.48%), and Callicarpa japonica (13.85%) were dominant in the shrub layer, while Ainsliaea acerifolia (23.41%), Disporum smilacinum (9.45%), and Oplismenus undulatifolius (5.62%) were dominant in the herbaceous layer. In the shrub layer, the richness of Smilax china, Lonicera subsessilis, and Philadelphus schrenkii was high when the basal area and the stand density of an upper layer were high. By contrast, smaller basal area and stand density were associated with the richness of Acer pseudosieboldianum, Deutzia glabrata, Morus bombycis, and Cornus kousa. Furthermore, it was found out that the impact of the basal area and the stand density on the herbaceous layer decreased over time, while the herb layer's species composition was greatly affected by cover degrees of Euonymus oxyphyllus and Acer pseudosieboldianum in the shrub layer. In conclusion, the number of species in the understory vegetation in Gwangneung forest is continuously decreasing, thus implying that species diversity, basal area, and stand density of an upper layer can influence the species composition in understory vegetation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.11-22
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• 2009

Long-term rainfall-runoff modeling is a key element in the Earth's hydrological cycle, and associated with many different aspects such as dam design, drought management, river management flow, reservoir management for water supply, water right permission or coordinate, water quality prediction. In this regard, hydrologists have used the hydrologic models for design criteria, water resources assessment, planning and management as a main tool. Most of rainfall-runoff studies, however, were not carefully performed in terms of considering reservoir effects. In particular, the downstream where is severely affected by reservoir was poorly dealt in modeling rainfall-runoff process. Moreover, the effects can considerably affect overall the rainfallrunoff process. An objective of this study, thus, is to evaluate the impact of reservoir operation on rainfall-runoff process. The proposed approach is applied to Anseong watershed, where is in a mixed rural/urban setting of the area and in Korea, and has been experienced by flood damage due to heavy rainfall. It has been greatly paid attention to the agricultural reservoirs in terms of flood protection in Korea. To further investigate the reservoir effects, a comprehensive assessment for the results are discussed. Results of simulations that included reservoir in the model showed the effect of storage appeared in spring and autumn when rainfall was not concentrated. In periods of heavy rainfall, however, downstream runoff increased in simulations that do not consider reservoir factor. Flow duration curve showed that changes in streamflow depending upon the presence or absence of reservoir factor were particularly noticeable in ninety-five day flow and low flow.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.387-397
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• 2023

Plant height is a growth parameter that provides visible insights into the plant's growth status and has a high correlation with yield, so it is widely used in crop breeding and cultivation research. Investigation of the growth characteristics of crops such as plant height has generally been conducted directly by humans using a ruler, but with the recent development of sensing and image analysis technology, research is being attempted to digitally convert growth measurement technology to efficiently investigate crop growth. In this study, the canopy height of rice grown at various nitrogen fertilization levels was measured using a laser scanner capable of precise measurement over a wide range, and a comparative analysis was performed with the actual plant height. As a result of comparing the point cloud data collected with a laser scanner and the actual plant height, it was confirmed that the estimated plant height measured based on the average height of the top 1% points showed the highest correlation with the actual plant height (R² = 0.93, RMSE = 2.73). Based on this, a linear regression equation was derived and used to convert the canopy height measured with a laser scanner to the actual plant height. The rice growth curve drawn by combining the actual and estimated plant height collected by various nitrogen fertilization conditions and growth period shows that the laser scanner-based canopy height measurement technology can be effectively utilized for assessing the plant height and growth of rice. In the future, 3D images derived from laser scanners are expected to be applicable to crop biomass estimation, plant shape analysis, etc., and can be used as a technology for digital conversion of conventional crop growth assessment methods.

• Journal of Global Scholars of Marketing Science
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• v.18 no.2
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• pp.223-252
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• 2008

In this study, we attempt to propose a choice-based diffusion model with switching cost, which can be used to forecast the dynamic substitution and competition among previous and new products at both individual-level and aggregate level, especially when market data for new products is insufficient. Additionally, we apply the proposed model to the empirical case of substitution and competition among Analog Cable TV that represents previous fixed charged broadcasting service and Digital Cable TV and Internet Protocol TV (IPTV) that are new ones, verify the validities of our proposed model, and finally derive related empirical implications. For empirical application, we obtained data from survey conducted as follows. Survey was administered by Dongseo Research to 1,000 adults aging from 20 to 60 living in Seoul, Korea, in May of 2007, under the title of 'Demand analysis of next generation fixed interactive broadcasting services'. Conjoint survey modified as follows, was used. First, as the traditional approach in conjoint analysis, we extracted 16 hypothetical alternative cards from the orthogonal design using important attributes and levels of next generation interactive broadcasting services which were determined by previous literature review and experts' comments. Again, we divided 16 conjoint cards into 4 groups, and thus composed 4 choice sets with 4 alternatives each. Therefore, each respondent faces 4 different hypothetical choice situations. In addition to this, we added two ways of modification. First, we asked the respondents to include the status-quo broadcasting services they subscribe to, as another alternative in each choice set. As a result, respondents choose the most preferred alternative among 5 alternatives consisting of 1 alternative with current subscription and 4 hypothetical alternatives in 4 choice sets. Modification of traditional conjoint survey in this way enabled us to estimate the factors related to switching cost or switching threshold in addition to the effects of attributes. Also, by using both revealed preference data(1 alternative with current subscription) and stated preference data (4 hypothetical alternatives), additional advantages in terms of the estimation properties and more conservative and realistic forecast, can be achieved. Second, we asked the respondents to choose the most preferred alternative while considering their expected adoption timing or switching timing. Respondents are asked to report their expected adoption or switching timing among 14 half-year points after the introduction of next generation broadcasting services. As a result, for each respondent, 14 observations with 5 alternatives for each period, are obtained, which results in panel-type data. Finally, this panel-type data consisting of $4{\ast}14{\ast}1000=56000$observations is used for estimation of the individual-level consumer adoption model. From the results obtained by empirical application, in case of forecasting the demand of new products without considering existence of previous product(s) and(or) switching cost factors, it is found that overestimated speed of diffusion at introductory stage or distorted predictions can be obtained, and as such, validities of our proposed model in which both existence of previous products and switching cost factors are properly considered, are verified. Also, it is found that proposed model can produce flexible patterns of market evolution depending on the degree of the effects of consumer preferences for the attributes of the alternatives on individual-level state transition, rather than following S-shaped curve assumed a priori. Empirically, it is found that in various scenarios with diverse combinations of prices, IPTV is more likely to take advantageous positions over Digital Cable TV in obtaining subscribers. Meanwhile, despite inferiorities in many technological attributes, Analog Cable TV, which is regarded as previous product in our analysis, is likely to be substituted by new services gradually rather than abruptly thanks to the advantage in low service charge and existence of high switching cost in fixed charged broadcasting service market.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.214-223
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• 2013

BACKGROUND: This study focused on the development of an analytical method about dichlorprop (DCPP; 2-(2,4-dichlorophenoxy)propionic acid) which is a plant growth regulator, a synthetic auxin for agricultural commodities. DCPP prevents falling of fruits during their growth periods. However, the overdose of DCPP caused the unwanted maturing time and reduce the safe storage period. If we take fruits with exceeding maximum residue limits, it could be harmful. Therefore, this study presented the analytical method of DCPP in agricultural commodities for the nation-wide pesticide residues monitoring program of the Ministry of Food and Drug Safety. METHODS AND RESULTS: We adopted the analytical method for DCPP in agricultural commodities by gas chromatograph in cooperated with Electron Capture Detector(ECD). Sample extraction and purification by ion-associated partition method were applied, then quantitation was done by GC/ECD with DB-17, a moderate polarity column under the temperature-rising condition with nitrogen as a carrier gas and split-less mode. Standard calibration curve presented linearity with the correlation coefficient ($r^2$) > 0.9998, analysed from 0.1 to 2.0 mg/L concentration. Limit of quantitation in agricultural commodities represents 0.05 mg/kg, and average recoveries ranged from 78.8 to 102.2%. The repeatability of measurements expressed as coefficient of variation (CV %) was less than 9.5% in 0.05, 0.10, and 0.50 mg/kg. CONCLUSION(S): Our newly improved analytical method for DCPP residues in agricultural commodities was applicable to the nation-wide pesticide residues monitoring program with the acceptable level of sensitivity, repeatability and reproducibility.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.82-92
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• 1976

The study was carried out to investigate the changes of the various chemical components and the microflora during the aging period of Korean navive Kochuzang. (Red pepper soybean paste) Korean native maeju loaves were separated into surface and inner parts. Three kinds of Korean native Kochuzang were prepared from surface part, inner part, and ordinary of maeju. The selection and the indentification of the high enzyme producing strains from the microflora and characteristics of their enzymes were studied. I. The changes of the various chemical components during the aging period of Kochuzang. 1) The changes of pH in the 3 kinds of Kochuzang displayed rapid decrease for the first 10 days after preparing and gradual curve of decrease until 60 days, but slight increase for the next 30 days. The pH of the surface part Kochuzang was lower than that of inner part or ordinary Kochuzang. 2) The total acid contents in the 3 kinds of Kochuzang showed gradual increase until the 60 days but it slowly reduced after this time. 3) The total nitrogen contents in the 3 kind of Kochuzang showed gradual inerease up to the 60 days, but slight decrease after this time. 4) The changes of trichloroacetic acid soluble nitrogen in the 3 kinds of Kochuzang showed a remarkable increase for the first 10 days, however gradual increase after this time. 5) The increase of amino nitrogen contents in the 3 kinds of Kochuzang seemed to be remarkable until the first 30 days, however to be less remarkable after this time. 6) The contents of reducing sugar in the 3 kinds of Kochuzang showed remarkable increase until the first 50 days and it slowly reduced after this time. II. The changes of microflora during the aging period of Kochuzang. 1) Aerobic, anaerobic bacteria and mold in the 3 kinds of Kochuzang were increased until the first 30 to 40 days, but they were reduced after this time. 2) No yeast in the three kinds of Kochuzang appeared until the first 20 days. Yeast were proved to grow, when the pH value was decreased below 5.4 after the 30 days. Yeasts in the surface part and ordinary Kochuzang were gradually increased and those in the inner part Kochuzang were decreased as aging. III. The selection and identification of high amylase and protease producing strains from the microflora during the aging period of Kochuzang. 1) The amylase and protease highly producing strains from microflora were identified as Bacillus subtilis-P, Bacillus subtilis-G, Bacillus licheniformis-K, Aspergillus oryzae-B. 2) Amylase activity of Aspergillus oryzae-B was highest among the strains and the strains in order of the higher activity to the lower one were Bacillus subtilis-P Bacillus licheniformis-K, Bacillus subtilis-G. Protease activities of Aspergillus oryzae-B and Bacillus subtilis-P were about the same and the strains in order of the higher activity to the lower one were Bacillus licheniformis-K, Bacillus subtilis-G. 3) Amylase activity was inhibited more than protease activity was with NaCl concentration. Amylase activity was inhibited by 45 to 65 percent and protease activity by 40 to 46 percent at the concentration of 15 percent NaCl, which was the average concentration of NaCl in Kochuzang.