• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1353-1369
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• 2023

In the event of a disaster accident at sea, the scale of damage will vary due to weather effects such as wind, currents, and tidal waves, and it is obligatory to minimize the scale of damage by establishing appropriate control plans through quick on-site identification. In particular, it is difficult to identify pollutants that exist in a thin film at sea surface due to their relatively low viscosity and surface tension among pollutants discharged into the sea. Therefore, this study aims to develop an algorithm to detect suspended pollutants on the sea surface in RGB images using imaging equipment that can be easily used in the field, and to evaluate the performance of the algorithm using input data obtained from actual waters. The developed algorithm uses image enhancement techniques to improve the contrast between the intensity values of pollutants and general sea surfaces, and through histogram analysis, the background threshold is found,suspended solids other than pollutants are removed, and finally pollutants are classified. In this study, a real sea test using substitute materials was performed to evaluate the performance of the developed algorithm, and most of the suspended marine pollutants were detected, but the false detection area occurred in places with strong waves. However, the detection results are about three times better than the detection method using a single threshold in the existing algorithm. Through the results of this R&D, it is expected to be useful for on-site control response activities by detecting suspended marine pollutants that were difficult to identify with the naked eye at existing sites.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.700-708
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• 2012

In order to optimize a method to determine the firmness of Chinese cabbage, hardness of midrib tissues was examined based on their chronological order of emergence. Texture measurement using volodkevich bite jaws gave a consistent and highest regression ($r^2=0.85$) between firmness and the order of leaf emergence, while blade set, cylinder probe, and crisp fracture support rig showed a lower coefficient of determination. Thickness of midrib tissue within an individual head from 16 cultivars of Chinese cabbage was positively correlated with the order of emergence, becoming thinner toward inner leaves. Mean thickness of midrib tissue from the head ranged from 7.74 mm for 'CR-shingshing' and 9.28 mm for 'Norangyeorum'. The covariance of leaf thickness within a head was highly cultivar-dependent, ranging from 23.6% for 'Chihili' and 5.8% for 'Bulam'. Firmness of the midrib tissue, defined as maximum peak height per tissue thickness, became higher from outer to inner leaves, showing $2^{nd}$ order of regression. Mean firmness of the midrib tissue from individual head varied from 1.58 N for 'Rangno' to 3.46 N for 'CR-shingshing'. The $10^{th}$ or $11^{th}$ leaf brought the best correlation coefficient (r = 0.81) between firmness of an individual leaf and the mean firmness of the entire leaves in a head, suggesting a reliable and rapid method to estimate the firmness of a head in lieu of examining all leaves in the head. The relationship between firmness of midrib tissue and dry mass ($r=0.70^{**}$) as well as cell wall content ($r=0.58^*$) of the head were positively correlated. Results obtained from the present study suggested that a new method to determine midrib firmness would enable to clarify the relationship between textural quality of fresh Chinese cabbage and their processed product, 'Kimchi'. It will also be important to apply this method to screen textural quality of various genotypes under breeding programs.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1137-1147
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• 2022

River and groundwater stages are the main elements in the hydrologic cycle. They are spatially correlated and can be used to evaluate hydrological and agricultural drought. Stochastic simulation is often performed independently on hydrological variables that are spatiotemporally correlated. In this setting, interdependency across mutual variables may not be maintained. This study proposes the Bayesian vector autoregression model (VAR) to capture the interdependency between multiple variables over time. VAR models systematically consider the lagged stages of each variable and the lagged values of the other variables. Further, an autoregressive model (AR) was built and compared with the VAR model. It was confirmed that the VAR model was more effective in reproducing observed interdependency (or cross-correlation) between river and ground stages, while the AR generally underestimated that of the observed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.40-48
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• 2023

In this paper, a sensor-based monitoring system was established to analyze the long-term behavioral characteristics of the caisson quay wall, a representative structural type in port facilities. Data was collected over a period of approximately 10 months. Based on existing literature, anomalous behaviors of port facilities were classified, and a measurement system was selected to detect them. Monitoring systems were installed on-site to periodically collect data. The collected data was transmitted and stored on a server through LTE network. Considering the site conditions, inclinometers for measuring slope and crack meters for measuring spacing and settlement were installed. They were attached to two caissons for comparison between different caissons. The correlation among measured data, temperature, and tidal level was examined. The temperature dominated the spacing and settlement data. When the temperature changed by approximately 50 degrees, the spacing changed by 10 mm, the settlement by 2 mm, and the slope by 0.1 degrees. On the other hand, there was no clear relationship with tidal level, indicating a need for more in-depth analysis in the future. Based on the characteristics of these collected database, it will be possible to develop algorithms for detecting abnormal states in gravity-type quay walls. The acquisition and analysis of long-term data enable to evaluate the safety and usability of structures in the event of disasters and emergencies.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.206-210
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• 2017

This study was performed to develope mathematical models for predicting growth kinetics of Staphylococcus aureus in the processed meat product, pyeonyuk. Growth patterns of S. aureus in pyeonyuk were determined at the storage temperatures of 4, 10, 20, and $37^{\circ}C$ respectively. The number of S. aureus in pyeonyuk increased at all the storage temperatures. The maximum specific growth rate (${\mu}_{max}$) and lag phase duration (LPD) values were calculated by Baranyi model. The ${\mu}_{max}$ values went up, while the LPD values decreased as the storage temperature increased from $4^{\circ}C$ to $37^{\circ}C$. Square root model and polynomial model were used to develop the secondary models for ${\mu}_{max}$ and LPD, respectively. Root Mean Square Error (RMSE) was used to evaluate the developed model and the fitness was determind to be 0.42. Therefore the developed predictive model was useful to predict the growth of S. aureus in pyeonyuk and it will help to prevent food-born disease by expanding for microbial sanitary management guide.

• Journal of Korean Home Economics Education Association
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• v.26 no.1
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• pp.1-16
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• 2014

The purpose of this research is to develop a theme-based integrated teaching/learning plan in clothing, food, and housing in home economics and to apply the developed process in classes for evaluation in order to identify the suitability in schools. The theme-based integrated teaching/learning plan developed on the basis of textbooks consist four sub-themes; choosing($1^{st}$ and $2^{nd)$ lessons), using($3^{rd}$ lesson), processing ($4^{th}$ lesson), and alternatives($5^{th}$ and $6^{th}$ lessons) under the main theme of 'green family life'. The results from 20 individual and group activities showed that the students actively solved the problems when the presented cases were related to their own lives or experiences. The opportunity to implement green life through activities motivated students' willingness to proceed in real life. However, it is vital to assist integrated thinking through various examples before beginning due to students with difficulties connecting the issue from one area to the other during the problem-focused activity. The students' ability to solve the activity workbook had been improved as the lessons continued. From the survey questions on the theme-based integrated lessons, all items associated with integration of clothing, foods, and housing were positively responded. Also, questions regarding general understanding, suitability and satisfaction on the teaching/learning process were marked positive. The conclusion could be that the integrated theme related to clothing, food, and housing in our life would be appropriate for green family life. The theme-based integrated teaching/learning plan is effective in understanding the occurrence of green family life in relation with clothing, food, and housing, identifying the practical ideas implementing green life in those areas, and improving the integrated ability to solve the green life related problems. However, this research has its weakness in generalizing the results due to its limited survey respondents and post-evaluation being the only assessment conducted.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.186-193
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• 2016

An analytical method was developed for the determination of oxathiapiprolin in agricultural commodities. Oxathiapiprolin is a new oomycide (fungicide of piperidinyl thiazole isoxazoline class) which controls downy mildew in cucurbits caused by Pseudoperonospora cubensis (oomycete plant pathogen). Agricultural commodities were extracted with acetonitrile and partitioned with dichloromethane to remove the interference, adjusting pH between 9 and 10 by 1 N sodium hydroxide. After purification by silica SPE cartridge to clean up the interference of organic compounds, they were finally quantified by HPLC-UVD (high performance liquid chromatograph ultraviolet detector) using a wavelength at 260 nm and confirmed by LC-MS (liquid chromatograph mass spectrometer) in electro-spray ionization positive ion mode. The standard calibration curve was linear with coefficients of determination ($r^2$) 1.00 over the calibration ranges (0.025-2.5 mg/L). Recoveries were ranged between 86.7 to 112.7%, with relative standard deviations less than 10% at three concentration levels (LOQ, 10LOQ, and 50LOQ) performing five replicates. The overall results were determined and estimated according to the CODEX guidelines (CAC/GL40). The proposed method for determination of oxathiapiprolin residues in agricultural commodities can be used as an official method.

• Journal of dental hygiene science
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• v.11 no.6
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• pp.543-551
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• 2011

Critical thinking is recognized as core competency for dental hygiene practice. The purpose of this study was to investigate relationship between critical thinking disposition and grade, types of educational programs and satisfaction with interpersonal relationship, major, clinical practice. Total 909 students in associate and baccalaureate dental hygiene educational program completed self-reported questionnaire on critical thinking disposition inventory developed by Yoon(2004). The mean score for critical thinking disposition was 3.38~3.39 on a 5 point scale. There was no difference in critical thinking disposition scores between students of associate and baccalaureate programs. There was no difference in critical thinking disposition scores between grade of students. The results showed a statistically significant relationship between critical thinking disposition and satisfaction with interpersonal relationship and major. Multivariate analysis of variance(MANOVA) revealed that all subscales for three groups according to satisfaction with interpersonal relationship were significantly different(Pillai's trace=0.075, F(14,1782)=4.979, p<0.001) and all subscales for three groups according to satisfaction with major were significantly different(Pillai's trace=0.035, F(14,1728)=2.257, p=0.005).

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.271-279
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• 2016

To evaluate exposure characteristics of the insecticide imidacloprid to apple orchard workers during treatment on orchard fields and evaluate its potential risk using a whole body dosimetry (WBD) method, 1,000-time diluted acephate+imidacloprid 25(20+5)% solutions were sprayed on 10 apple orchard fields in Cheongju with a speed sprayer at a rate of 3,000 L/ha/person, after put on clothes such as inner/outer clothes, personal air pump with a IOM sampler, nitrile glove and mask. Exposure test included mixing, loading and application steps. The test pesticide imidacloprid residues in the collected samples were analyzed with a HPLC-DAD. Recoveries ranged from 81.5 to 108.6% for analytical method validation and from 73.8 to 86.7% for field recovery. Total exposed amounts to mixer/loader and applicator were found to be 0.0014-0.0279% of total applied active ingredient of imidacloprid. Glove exposure of both mixer/loader and applicator was higher than the other parts. Margins of safety of mixer/loader and applicator were calculated to be 97-355 and 46-196, respectively, indicating that exposure risk of imidacloprid to apple orchard workers by spraying with a speed sprayer was very low.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.781-787
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• 2009

This report investigates the economic proprieties of commercial 50,000 barrel per day direct/indirect coal liquefaction(DCL/ICL) plants to produce commercial-grade diesel and naphtha liquids. The scope of the study includes capital and operating cost estimates, sensitivity analyses and a comparative financial analyses. Based on plant capacity of 50,000BPD, employing Illinois #6 bituminous coal as feed coal, the total capital cost appeared $3,994,858,000(DCL) and $4,962,263,000(ICL). Also, the internal rate of return of DCL/ICL appeared 13.27% and 12.68% on the base condition respectively. In this case, coal price and sale price of products were the most influence factors. And ICL's payback period(6.8 years) was longer than DCL's(6.6 years). According to sensitivity analyses, the important factors on both DCL/ICL processes were product sale price, feed coal price and the capital cost in order.