• Korean Journal of Community Nutrition
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• v.11 no.1
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• pp.39-51
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• 2006

This study was conducted to investigate the differences in daily nutrient intakes, dietary habits and nutrition knowledge between male and female college students. Male undergraduate students 004 subjects) and female undergraduate students (229 subjects) , enrolled at H University in Daejeon, were recruited for this study. The mean age of the subjects was 22.9 year in male and 20.4 year in female students. Daily intakes of energy and nutrients were calculated from the records of one day of dietary food intakes by 24-hour recall method, and general information, dietary habits and attitudes, food intake frequency and food preferences and knowledge for food and nutrition were surveyed through a questionnaire. About $70.1\%$ of male and $66.1\%$ of female students were in the normal range of BMI (18.5 - 23), and $25.2\%$ of male students were over-weighted in contrast to $27.7\%$ of female students were underweight. Males and females were taking $77.2\%$ and $77.9\%$ of RDA for energy, respectively, and $54.8\%$ of male and $48.0\%$ of female students were taking energy under $75\%$ of RDA. Many of them showed deficient intakes of calcium, iron, vitamin A and riboflavin. Average of MAR was 0.75 in male and 0.72 in female students. NAR for calcium, iron, vitamin A and riboflavin in male students were 0.55, 0.69,0.75 and 0.61, respectively, compared to 0.53, 0.51, 0.70 and 0.67 in female students. The nutrients, which have INQ less than 1, were calcium and riboflavin in male, compared to calcium, iron, and riboflavin in female students. There were no gender differences in meal regularity and meal skipping rates, but female students showed higher rates of skipping dinner than males (p < 0.001) About $50.8\%$ of female students were ingesting snacks 1 - 2 time/day, compared to $27.1\%$ of male students. For the food intake frequency, fruit group was significantly eating more for female than male students (p< 0.001) Though female students got higher scores for nutritional knowledge test (p < 0.001) than male students, they did not show better dietary habits or dietary attitudes than male students actually. Therefore, a more active and actual education program accustomed to the different genders and ages with focus on real changing of dietary behaviors needs to be developed and run in schools and local departments.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.567-572
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• 2005

In this study, a lab-scale test was performed to apply the ozone process in drinking water treatment plant using dissolved ai, flotation(DAF). The kinetic study on the ozone decay and hydroxyl(OH) radical formation was investigated by several parameters, such as I.D(Instantaneous ozone demand), $k_c$(ozone decomposition rate), ozone-Ct and OH radical-Ct. Ozonation of several target waters, such as raw water, DAF treated water and filtrate, was conducted to select the optimum position and dosage of ozone process. The highest value of Ozone-Ct and OH radical-Ct was observed at DAF treated water at initial run time($0{\sim}30\;min$). From the results of ozonation, the intermediate ozonation was proposed as the optimum position and the effective dose of ozone was determined to be $1{\sim}2\;mg/L$.

• Tunnel and Underground Space
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• v.30 no.5
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• pp.473-483
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• 2020

This paper examines the vertical stress change concentrated on mine pillar which occurs due to the stress disturbance from opening excavation at room and pillar mine by FLAC3D, a finite difference method (FDM) software. The mesh size combination is decided with a careful consideration of relative error and run-time, then its performance is verified. A series of numerical analyses is conducted and the vertical stress at central pillar was observed for the test cases of 1×1 to 11×11 mine pillars, 40 m to 320 m depth with 40 m difference. The results show that the vertical stress of pillar approaches to the similar value with the value estimated by tributary area theory(TAT) when the development area (N_P) is increased or the height of overburden (H_OB) is decreased, while it is overestimated in the opposite case. Furthermore, it also represents that the vertical stress factor (VSF) converges to a specific value when the depth is increased whille keeping the development area identical.

• Journal of the Korean Data and Information Science Society
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• v.26 no.5
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• pp.1129-1139
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• 2015

Inference process generates additional triples from knowledge represented in RDF triples of semantic web technology. Tens of million of triples as an initial big data and the additionally inferred triples become a knowledge base for applications such as QA(question&answer) system. The inference engine requires more computing resources to process the triples generated while inferencing. The additional computing resources supplied by underlying resource pool in cloud computing can shorten the execution time. This paper addresses an algorithm to allocate the number of computing nodes "elastically" at runtime on Hadoop, depending on the size of knowledge data fed. The model proposed in this paper is composed of the layered architecture: the top layer for applications, the middle layer for distributed parallel inference engine to process the triples, and lower layer for elastic Hadoop and server visualization. System algorithms and test data are analyzed and discussed in this paper. The model hast the benefit that rich legacy Hadoop applications can be run faster on this system without any modification.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.2
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• pp.87-95
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• 1983

Trihalomethane removal efficiency by a fixed bed carbon adsorber was a subject of this study. Along with laboratory scale column operations, a simple adsorption model was developed to predict removal efficiency. The adsorption model includes an overall mass transfer coefficient, K and Freundlich adsorption constants, $K_F$ and n. Simulation results showed that increasing K and $K_F$ or decreasing n would take more loading and prolong run time of the adsorption bed. Typical S-shaped breakthrough curves were obtained from the experiments. The operational results at $20^{\circ}C$ and $25^{\circ}C$ indicated that a moderate difference in water temperature would not affect the treatment efficiency significantly. The adsorption constants determined from the column operation and the model simulation were reasonably close to those obtained from the isotherm test. It may be concluded that trihalomethane can be removed successfully by a fixed bed carbon adsorber.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.390-397
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• 2010

Residual solvents in foods are defined as organic volatile chemicals used or produced in manufacturing of extracts or additives, or functional foods. The solvents are not completely eliminated by practical manufacturing techniques and they also may become contaminated by solvents from packing, transportation or storage in warehouses. Because residual solvents have no nutritional value but may be hazardous to human health, there is a need to remove them from the final products or reduce their amounts to below acceptable levels. The purpose of this study was to develop and evaluate an analytical method for the screening of residual solvents in health functional foods. Furthermore, the aim of this study was to constitute a reasonable management system based on the current state of the market and case studies of foreign countries. Eleven volatile solvents such as MeOH, EtOH, trichloroethylene and hexane were separated depending on their column properties, temp. and time using Gas Chromatography (GC). After determining the GC conditions, a sample preparation method using HSS (Head Space Sampling) was developed. From the results, a method for analyzing residual solvents in health functional foods was developed considering matrix effect and interference from the sample obtained from the solution of solvents-free health functional foods spiked with 11 standards solutions. Validation test using the developed GC/HSS/MS (Mass Spectrometry) method was followed by tests for precision, accuracy, recovery, linearity and adequate sensitivity. Finally, examination of 104 samples grouped in suits was performed by the developed HSS/GC/MS for screening the solvents. The 11 solvents were isolated from health functional foods based on vapor pressure difference, and followed by separation within 15 minutes in a single run. The limt of detection (LOD), limit of quantification (LOQ), recovery and coefficient of variation (C.V.) of these compounds determined by the HSS/GC/MS were found to be 0.1 pg/mL, 0.1-125 pg/g, 51.0-104.6%, and less than 15%, respectively. Using the developed HSS/GC/MS method, residual solvent from 16 out of 104 health functional products were detected as a EtOH. This method therefore seems t o be a valuable extension ofanalytical method for the identification of residual solvents in health functional food.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.139-148
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• 2017

Ground subsidence caused by damaged water pipe and sewer is recently increasing due to the aging of city and pipeline in many city. Although many recent studies have verified characteristics of ground subsidence due to wastewater pipe breakdown, research about characteristics of ground subsidence due to water pipe is insignificant. subsidence due to water pipe is insignificant. This study aims to identify the ground failure mechanism caused by water and sewer pipe breakdown. Accordingly, we conducted an indoor model experiment to verify characteristics of ground subsidence considering characteristics of ground and ground failure. The water pipe pressure and velocity head was considered to find out ground subsidence mechanism. Also comparative analysis is conducted by analyzing relative density and fine-grain content considering embedded condition of water pipe. When the relative density and seepage pressure is low, small scale ground subsidence can occur, but when the conditions are opposite, ground subsidence occur in large scale and expands to ground level over time. Furthermore, it is acknowledgeable that ground cavity that is formed after soil run off due to seepage in deep earth, maintains steady strength and stays on the ground level for long period.

• Journal of Practical Engineering Education
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• v.8 no.1
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• pp.39-47
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• 2016

Owing to increasing concern that jobseekers are wasting too much time and effort building up so-called "spec" skills to get a decent job, many companies including state-run enterprises are now hiring rookies based on their job competency rather than test scores unrelated to the job. However, universities which are mainly responsible for training professional personnel needed for various kinds of companies and factories are reluctant to adopt NCS-based educational courses. The NCS defines how much knowledge and skill are required to work in a certain industry and then evaluates them. Although the Korean government and several junior colleges have been tentatively operating the course-based qualification system at the "industrial technician" level since 2014, the results are falling far short of diverse stakeholders' expectations. Therefore, there are urgent needs to study how to develop NCS-based curriculum at the university level, and how to strengthen the linkage between work, training, and qualification.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.586-593
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• 2019

The purpose of this study is to investigate the perception of fire safety education in middle and high school teachers. The results of this study provide basic data necessary for future school safety education. The research was carried out using a questionnaire given to 317 school teachers. The frequency of the questionnaire was calculated from frequency analysis using SPSS version 19.0. A chi-square test was conducted to verify the analyzed questionnaire data. Cronbach's alpha for fire safety awareness in the respondents is 0.845, which is very reliable. According to the results of the survey, fire safety education currently conducted in schools is aimed at having a safe lifestyle and respect for life. The training is conducted once every six months, on average, and training time is 30 to 45 minutes. Fire safety education in schools is conducted in the form of experience-oriented education in cooperation with fire-related organizations following the plan of the school. Educational texts are used and utilized through the Internet and in related publications. Under the present circumstances, it is necessary to secure sufficient space to run an experience-related education program and to actively participate in the students' fire safety education at the school.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.37-46
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• 2019

The purpose of this study is to explore the effects of the use of artificial intelligence chatbots on improving Korean college students' English grammar skills. 70 undergraduate students participated in the present study. They were taking a General English class offered by a university in Korea. There were two groups in this study. Participants in the chatbot group consisted of 36 students while those in the human group were 34. Over 16 weeks, the chatbot group engaged in ten chat sessions with a chatbot while the human group had a chat with a human chat partner. Both pre- and post-tests were performed to examine changes in the participants' grammar skills over time. To compare the improvement between the two groups, an independent t-test was then run. Main findings are as follows: First, participants in both groups significantly improved their English grammar skills, indicating the beneficial effects of engaging in chat. Also, there was a statistically significant difference in the improvement between the chatbot and human groups, indicating the superior effects of the chatbot use. This study confirmed the improved grammar skills by the participants in the chatbot group, comparison with those in the human group. Based on these findings, suggestions for the future chatbot study are discussed.