• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.226-233
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• 2023

High solar radiation in summer season causes excessive respiration of crops and reduces photosynthesis. In addition, the rainy season, which mainly occurs in summer, causes a low light condition inside the greenhouse. A low light condition can reduce crop growth and yield. This study was conducted to evaluate the effect of shade and supplemental lighting on the growth and yield of cucumber during summer season. Cucumber grafted seedlings were transplanted in two plastic greenhouses on August 30, 2022. To reduce the light intensity inside the greenhouse, a 50% shading screen was installed in one greenhouse. Supplemental lighting was conducted from September 7, 2022 to October 20, 2022. HPS (high-pressure sodium lamp), W LED (white LED, red:green:blue = 5:3:2), and RB LED (combined red and blue LED, red:blue = 7:3) were used for supplemental lighting sources, and non-treated (nonsupplemental lighting) was as the control. The supplemental lighting was conducted before sunrise and after sunset for 2 hours with a photosynthetic photon flux density of 150 ± 20 µmol·m^-2·s^-1. The plant height, leaf length, leaf width, and SPAD value tended to increase in the shading group. RB LED increased stem diameter regardless of shading treatment. Fresh and dry weights of fruits were not significantly different in shading and supplemental lighting. Average fresh weight of fruits was not significantly different among supplemental lighting as the harvest date passed. In conclusion, in this study 50% shade treatment significantly improved the growth of cucumber during the summer season. In addition, the growth and fruit characteristics are better than the control without supplemental lighting. This study can be used as basic research data for applying supplemental lighting technology to cucumber cultivation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.2
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• pp.80-98
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• 2023

This study explores the effectiveness of various data preprocessing algorithms for improving subseasonal to seasonal (S2S) climate predictions from six climate forecast models and their Multi-Model Ensemble (MME) using a deep learning-based postprocessing model. A pipeline of data transformation algorithms was constructed to convert raw S2S prediction data into the training data processed with several statistical distribution. A dimensionality reduction algorithm for selecting features through rankings of correlation coefficients between the observed and the input data. The training model in the study was designed with TimeDistributed wrapper applied to all convolutional layers of U-Net: The TimeDistributed wrapper allows a U-Net convolutional layer to be directly applied to 5-dimensional time series data while maintaining the time axis of data, but every input should be at least 3D in U-Net. We found that Robust and Standard transformation algorithms are most suitable for improving S2S predictions. The dimensionality reduction based on feature selections did not significantly improve predictions of daily precipitation for six climate models and even worsened predictions of daily maximum and minimum temperatures. While deep learning-based postprocessing was also improved MME S2S precipitation predictions, it did not have a significant effect on temperature predictions, particularly for the lead time of weeks 1 and 2. Further research is needed to develop an optimal deep learning model for improving S2S temperature predictions by testing various models and parameters.

• Journal of Service Research and Studies
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• v.12 no.1
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• pp.25-35
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• 2022

Covid-19, of which the first patient in Korea occurred in January 2020, has affected various fields. Of these, the tourism sector might havebeen hit the hardest. In particular, since tourism-based industrial structure forms the basis of the region, Gangwon-province, and the tourism industry is the main source of income for small businesses and small enterprises, the damage is great. To check the situation and extent of such damage, targeting the Chuncheon region, where public access is the most convenient among the Gangwon regions, one-day tours are possible using public transportation from Seoul and the metropolitan area, with a general image that low expense tourism is recognized as possible, this study conducted empirical analysis through data analysis. For this, the general status of the region was checked based on the visitor data of Chuncheon city provided by the tourist information system, and to check the levels ofinterest in 2019, before Covid-19, and in 2020, after Covid-19, by comparing keywords collected from the web service sometrend of Vibe Company Inc., a company specializing in keyword collection, with SK Telecom's T-map search site data, which in parallel provides in-vehicle navigation service and communication service, this study analyzed the general regional image of Chuncheon-city. In addition, by comparing data from two years by developing a tourism popularity index applying keywords and T-map search site data, this study examined how much the Covid-19 situation affected the level of interest of visitors to the Chuncheon area leading to actual visits using a data analysis approach. According to the results of big data analysis applying the tourism popularity index after designing the data mart, this study confirmed that the effect of the Covid-19 situation on tourism popularity in Chuncheon-city, Gangwon-provincewas not significant, and confirmed the image of tourist destinations based on the regional characteristics of the region. It is hoped that the results of this research and analysis can be used as useful reference data for tourism economic policy making.

• Journal of Service Research and Studies
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• v.11 no.2
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• pp.37-66
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• 2021

This study aims to provide self-development opportunities to hair salons service workers through e-learning and provide the foundation of sustainable hair salons management by cultivating good talents to hair salons service business executives. In particular, the factors affecting e-learning achievement are identified according to learner characteristics to see whether these factors affect the satisfaction of e-learning learners and also affect the performance of management. The results of the study are summarized as follows. As a result of hypotheses testing on the relationship between e-learning learning environment and e-learning satisfaction, it was found that the higher the level of e-learning content quality is, the higher the satisfaction of e-learning is, the higher the satisfaction of e-learning is, and that the higher the quality level of the support infrastructure is, the higher the satisfaction of e-learning is. The results of the hypotheses testing on the moderating effect of learner factors showed that the influence of the quality of the support infrastructure on the e-learning satisfaction differs according to the level of the learner's goal consciousness. However, it was found that the influence of content quality on e-learning satisfaction according to the level of the learners goal awareness, the influence of content quality on e-learning satisfaction according to the level of the aggressiveness of the learners learning attitude, and the influence of the quality of the support infrastructure on the e-learning satisfaction according to the level of the aggressiveness of learners learning attitude were found to identically demonstrate no moderating effects. The results of hypotheses testing on the relationships among e-Learning performance show that the higher the satisfaction of e-learning was, the higher the customer orientation was, and the higher the satisfaction of e-learning was, the higher the contribution of management performance was, and the higher the customer orientation was, the higher the contribution of management performance was. The implications of this study are as follows. First, the actual path of realiting e-learning performance could be identified that is this study provided organizational decision makers involved in the hair salons service operations with practical guidance for the introduction and expansion of successful educational systems. Second, the e-learning environment derived from the theoretical background is different from the e-learning environment required by the learners.

• Analytical Science and Technology
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• v.21 no.6
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• pp.474-479
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• 2008

Radioactivity of naturally occurring radioactive nuclides (NORN) such as $^{226}Ra$, $^{228}Ac$ and $^{40}K$ were investigated for surface sediments collected from Ordos, Alashan, Taklimakan deserts and Loess plateau regions in China. By a Gamma-ray spectrometry, specific activity (SA) and SA ratio (SAR) of the NORN were determined for each source region of Asian dust. Characterization of the source regions of Asian dust was performed with the SA and SAR values. SA of $^{226}Ra$ in the three desert regions have almost same values in the range of mean value 17.9~21.9 Bq/kg, however, the SA in Loess Plateau has much higher values in the mean value of 35 Bq/Kg. SA of $^{228}Ac$ in the Ordos and Alashan desert regions have almost same values in the range of mean value 27.1~27.2 Bq/kg, and those in Taklimakan desert and Loess Plateau were 31.7 and 49.0 Bq/kg, respectively. In case of 40K, the SA in all regions have similar values in the range of 636~943 Bq/kg. The mean SAR value of $^{226}Ra/^{228}Ac$ in four source regions was almost same in the range of 0.708-0.721. It is shown that relationship between $^{226}Ra$ and $^{228}Ac$ is clearly presented in the source regions. The mean SAR values of $^{226}Ra/^{40}K$, $^{228}Ac/^{40}K$ are 0.0209-0.056, 0.0287-0.0773, respectively.

• Analytical Science and Technology
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• v.22 no.5
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• pp.432-438
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• 2009

In order to develop the analytical method for the pharmaceutical tablets containing ranitidine HCl by square wave voltammetry (SWV), $5.00{\times}10^{-5}M$ ranitidine HCl solutions prepared with phosphate buffers of various pH values were investigated by SWV. The well defined main peak due to the electrochemical reduction of $-NO_2$ in the structure of ranitidine moved towards the cathodic direction by -70 mV/pH as the pH values were increased indicating the involvement of hydrogen in its reduction. The calibration curve, the plot of peak currents (Ip) vs. concentrations of ranitidine HCl in the range between $1.00{\times}10^{-7}M$ and $1.00{\times}10^{-5}M$ showed linearity with slopes of $232,530{\mu}A/M$ (pH 6.14), $289,015{\mu}A/M$ (pH 7.07) and $232,843{\mu}A/M$ (pH 8.01). When one pharmaceutical tablet was simply dissolved in the phosphate buffer with a pH value of 6.14 and determined by standard addition method using SWV, the within-day precision study (n=4) resulted in the contents of ranitidine HCl as $171{\pm}2.1mg$ ($102{\pm}1.3%$ of the specified contents, RSD of 1.2%) in a tablet of Curan$^{(R)}$. The inter-day precision for 5 days was 1.1% of RSD. For Zantac$^{(R)}$ the within-day precision study (n=4) showed the contents of ranitidine HCl as $167{\pm}0.8mg$ ($99{\pm}0.5%$ of the specified contents, RSD of 0.5%) in a tablet and the inter-day precision for 5 days was 0.3% of RSD.

• Analytical Science and Technology
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• v.20 no.4
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• pp.308-314
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• 2007

The analytical method of HPLC with the radial-flow electrochemical cell (RFEC) has been developed to determine doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin simultaneously by employing a reversed-phase chromatography. Anthracyclines were detected at -0.74 V vs. a Ag/AgCl (0.01 M NaCl) reference electrode, a potential of diffusion current plateau in the mobile phase. At a $V_f$ of 1.0 mL/min doxorubicin, epirubicin, daunorubicin and idarubicin appeared at a retention time ($t_r$) of 6.4 min, 7.4 min, 12.7 min and 18.4 min, respectively, while at a $V_f$ of 0.6 mL/min, doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin appeared at a $t_r$ of 9.9 min, 11.5 min, 13.5 min, 19.6 min and 28.7 min, respectively. The linearity between each anthracycline injected ($2.40{\times}10^{-7}M{\sim}1.42{\times}10^{-5}M$) and peak area (charge) was excellent with the square of the correlation coefficient ($R^2$) higher than 0.999. The detection limits were $1.0{\times}10^{-8}M{\sim}1.5{\times}10^{-7}M$ for the five anthracyclines. Within-day precision for the five anthracyclines were in reasonable relative standard deviations less than 3 % ($1.00{\times}10^{-6}M{\sim}1.42{\times}10^{-5}M$) except the lower concentrations less than $0.7{\mu}M$. Solid phase extractions of $1.00{\times}10^{-5}M$ epirubicin, $0.48{\times}10^{-5}M$ nogalamycin and $1.52{\times}10^{-5}M$ daunorubicin from human serum with a $C_{18}$ cartridge resulted in 97 %, 100 % and 90 % of recoveries, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.2
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• pp.83-90
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• 2023

The β-Ga₂O₃ has the most thermodynamically stable phase, a wide band gap of 4.8~4.9 eV and a high dielectric breakdown voltage of 8MV/cm. Due to such excellent electrical characteristics, this material as a power device material has been attracted much attention. Furthermore, the β-Ga₂O₃ has easy liquid phase growth method unlike materials such as SiC and GaN. However, since the grown pure β-Ga₂O₃ single crystal requires the intentionally controlled doping due to a low conductivity to be applied to a power device, the research on doping in β-Ga₂O₃ single crystal is definitely important. In this study, various source powders of un-doped, Sn 0.05 mol%, Sn 0.1 mol%, Sn 1.5 mol%, Sn 2 mol%, Sn 3 mol%-doped Ga₂O₃ were prepared by adding different mole ratios of SnO₂ powder to Ga₂O₃ powder, and β-Ga₂O₃ single crystals were grown by using an edge-defined Film-fed Growth (EFG) method. The crystal direction, crystal quality, optical, and electrical properties of the grown β-Ga₂O₃ single crystal were analyzed according to the Sn dopant content, and the property variation of β-Ga₂O₃ single crystal according to the Sn doping were extensively investigated.

• Analytical Science and Technology
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• v.22 no.6
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• pp.504-513
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• 2009

In this study, the safety of commercial herbal medicines was evaluated by determining concentration of hazardous heavy metals. 3,152 samples (244 types) purchased by individual packing unit from market in Seoul, were analyzed using ICP-MS and mercury analyzer. As a result, the content (mg $kg^{-1}$) of Pb was higher in the above-ground part (0.92) than underground part (0.43). But in case of As and Cd contents, there is slightly higher in the underground-parts (0.26, 0.13) than the above-ground parts (0.18, 0.08). There were many herbal medicines exceeding regulatory limits of Cd comparing with other metals. The levels of Hg seemed to be different between above-ground part(0.009) and underground part (0.008) but there was no sample exceeding tolerance limits. In the comparison of imported samples with domestic herbal medicines, it was shown that Pb, As, and Hg were measured highly in the imported ones, Cd was not significantly different (t-test, p<0.05). The significant correlation was observed between Pb and As (r=0.386, p<0.01) but there was no difference in other parts. The heavy metal contamination of herbal medicines measured in total amount of respective heavy metals (mg $kg^{-1}$) was high in Flos (6.241) and Caulis (2.238), and decreased in the order of Cortex (1.634), Herba (1.154), Perithecium (0.861), Rhizoma (0.828), Radix (0.825), Fructus (0.475), and was low in Semen (0.422) (ANOVA-test, p<0.05).

• Analytical Science and Technology
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• v.21 no.5
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• pp.383-391
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• 2008

International Agency for Research on Cancer (IARC) has classified it as a possible carcinogen and World Health Organization (WHO) has suggested 50 ng/mL as a guideline value for 1,4-dioxane. Considering the toxicity of 1,4-dioxane and ingestion rate of drinking water, the monitoring of 1,4-dioxane in drinking water in Nakdong river is very important. We analyzed 1,4-dioxane four times per year for the 12 samples of treated water and 4 samples of raw water in Nakdong river in Korea from 2000 to 2007 and surveyed the trend of concentrations of 1,4-dioxane. As a results of analysis, 1,4-dioxane was detected from 0.24 to 240.2 ng/mL in treated water and from 0.39 to 81.9 ng/mL in raw water from 2000 to 2007. The average concentrations are 22.68 ng/mL and 19.15 ng/mL in treated water and raw water, respectively. The detected concentrations was decreased but frequency of detection was not changed since establishment of regulation in 2004. Results of comparison of 95 percentile excessive cancer risk of 1,4-dioxane in treated and raw water were each $6.63{\times}10^{-6}$, $3.17{\times}10^{-6}$ before 2004 and $2.10{\times}10^{-6}$, $1.22{\times}10^{-6}$ after 2004. Also, comparing the detected concentration and frequency for each season, these were more detected the concentration and frequency for 1,4-dioxane in treated and raw water from winter to spring.