• Journal of the Korean Society of School Health
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• v.33 no.3
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• pp.184-193
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• 2020

Purpose: This study was designed to investigate the trends in school health research in Korea using probabilistic latent semantic analysis. The study longitudinally analyzed the abstracts of the papers published in 「The Journal of the Korean Society of School Health」 over the recent 17 years, which is between 2004 and August 2020. By classifying all the papers according to the topics identified through the analysis, it was possible to see how the distribution of the topics has changed over years. Based on the results, implications for school health research and educational uses of latent semantic analysis were suggested. Methods: This study investigated the research trends by longitudinally analyzing journal abstracts using latent dirichlet allocation (LDA), a type of LSA. The abstracts in 「The Journal of the Korean Society of School Health」 published from 2004 to August 2020 were used for the analysis. Results: A total of 34 latent topics were identified by LDA. Six topics, which were「Adolescent depression and suicide prevention」, 「Students' knowledge, attitudes, & behaviors」, 「Effective self-esteem program through depression interventions」, 「Factors of students' stress」, 「Intervention program to prevent adolescent risky behaviors」, and 「Sex education curriculum, and teacher」were most frequently covered by the journal. Each of them was dealt with in at least 20 papers. The topics related to 「Intervention program to prevent adolescent risky behaviors」, 「Effective self-esteem program through depression interventions」, and 「Preventive vaccination and factors of effective vaccination」 appeared repeatedly over the most recent 5 years. Conclusion: This study introduced an AI-powered analysis method that enables data-centered objective text analysis without human intervention. Based on the results, implications for school health research were presented, and various uses of latent semantic analysis (LSA) in educational research were suggested.

• International Journal of Clinical Preventive Dentistry
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• v.14 no.4
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• pp.216-221
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• 2018

Objective: In this study, we tried to investigate the antimicrobial activity of natural herbaceous plant-derived essential oils against oral disease-causing bacterial strains and establish the scientific evidences to apply them to the dentifrice, mouthwash, and other uses. Methods: We used the disk diffusion method with 23 types of 100% natural essential oils to verify the antimicrobial effect against Streptococcus mutans, Porphyromonas gingivalis, and Lactobacillus rhamnosus. After adhering to the surface of the plate culture medium, $20{\mu}l$ of the essential oil was prepared, and the diameter of the transparent ring was measured after incubation for 24 hours. All the experiments were repeated three times. Results: Among 23 types of oils, 13 were effective against all three strains: myrrh, ginger, basil, carrot seed, tea tree, patchouli, ylang ylang, cypress, lemongrass, cinnamon, peppermint, lavender, and eucalryptus. Seventeen oils were effective against S. mutans, and myrrh, basil, and carrot seed showed high antimicrobial activity. Eighteen oils were effective against P. gingivalis, and tea tree, carrot seed, and cinnamons showed high antimicrobial activity. Sixteen oils were effective against L. rhamnosus, and carrot seed and peppermint cinnamon showed high antimicrobial activity. Conclusion: Consequently, 13 essential oils showed the antimicrobial activity against three bacterial strains, which indicates these essential oils might be used as the effective materials to suppress the growth of oral-disease inducing microorganisms. Moreover, essential oils that have been analyzed activities in this study will be mixed up within the constant range and analyzed their antimicrobial effects to examine the synergistic activity among them.

• Journal of The Korean Association of Information Education
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• v.21 no.1
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• pp.151-160
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• 2017

The purpose of this study was to investigate the current status of information and communications technology(ICT) uses of the faculty members at national universities of education and to provide guidelines for ICT in education. The survey was conducted to examine factors related to the use of ICT, including faculty members' abilities to use ICT with respect to gender, age, and previous experiences with computers and to analyze their relevance to instructional methods. The results of the survey showed that female faculty members and male faculty members in their sixties and those with less years of teaching career were more likely to need support for using ICT than the others. The direct instructional method and discussion were the most frequently used; discussion was positively correlated with ICT uses. It was also found that faculty members anticipated more difficulties in using ICT in class and needed to work in a collaborative way and learn more effective use of ICT in the teaching and learning process.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.40-49
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• 2007

For effective watershed management, we must understand the complex and dynamic relationships of land uses and water quality. Despite numerous studies investigated the relationships between water quality and land use, there are increasing concerns on the geographical variation and lack of spatial integrations in previous studies. We investigated the relationships between land use and water quality characteristics in the Hwa-Sung estuarine reservoir watershed in Korea, which has spatially integrated land uses. The spatial variations of these relationships were also examined using zonal analysis. Water quality parameter were correlated positively with residential and forest and negatively with paddy and upland especially during base flow in the near buffer zone. During storm flow, correlation between land use and water quality was less apparent. Population and livestock density was correlated well to water quality parameter than just number of population and livestock. Relationships across zones, distinguished by distances from streams, were inconsistent and erratic, suggesting that the relationships between remote land uses and water quality may be affected more significantly by sub-basin characteristics than by the land use itself. The watersheds studied are mainly non-urban and their land uses are similar to typical watershed of other estuarine reservoirs, therefore, the correlation developed in this study might be helpful to manage other watersheds of estuarine reservoir. This methodology could be applied to other areas where the watershed characteristics are not significantly different from the study area.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.327-335
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• 2019

This study develops a prediction model for toilet and laundry water end-uses based on surveyed data which measured housing and household characteristics of 140 households over 5 years in Korea. Classical regression model assuming a normal distribution was not appropriate and estimated parameters were biased, because the distribution of measured water-uses was left-skewed. As an alternative to this problem, we considered the distribution of weibull and lognormal for each water-uses, and three regression models were compared using log-likelihood and scale parameter. As a result, weibull regression were chosen to be appropriate for both water-uses and also presented the factors that affect each water-use. This results expect that an insight is provided on water resources utilization and theoretical support role for effective water resource management.

• Journal of Korean Academy of Nursing
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• v.4 no.3
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• pp.1-12
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• 1974

It is the purpose of this study to determine an effective method of communication between teachers and students. This study was done by using the theory, methods and tools of transactional analysis as developed by Borne and Harris. In order to achieve this objective: First; The teacher and student communication process is to be used, noting the student's reaction when the teacher uses "Adult" and "Parent" stimulus. Second; The effectiveness of the reaction toward the "Adult" and "Parent" stimulus is to be determined with these objectives in mind. The problems of this research study are as follows; What influence on the response of the student is brought about by the method of communication used by the teacher? 1) When the teacher uses the "Parent" Stimulus method what response of the student is shown? 2) When the teacher uses the "Adult" Stimulus method what response of the student is shown? 3) What method of communication helps to promote the student′s growth? In order to determine the answers to these questions data was collected from 40 first year students at a school of nursing in Inchon. These students were divided into two groups and the unstandardized interview technique was used to interview each student for ten minutes. A tape recording was made of each interview and the nonverbal communication was recorded by process recording immediately following each interview. The recorded material obtained from the two groups was analysed and then the Borne and Harris transactional analysis method was used in analysing the writer of this thesis undertook. Hypothesis 1. When the teacher used the "Parent" stimulus the student′s response was more frequently "Child" than "Adult", the results showed a significant difference of P〈0.001. Hypothesis 2. When the teacher used the "Adult" Stimulus the student′s response was more frequently of "Adult" than "Child", the results showed a significant difference of P〈0.001, The following conclusions are drawn from this study: 1) There is an indication that the teachers use of "Parent" stimulus communication is not an effective method to increase the growth of the student. 3) Since the teachers use of "Adult" stimulus resulted in an increase in the "Adult" response of the student there is ah indication that use of an effective communication method can help the student to develop. The writer of this research paper suggests for further study the following; 1) A comparison of the differences in response to the giving of both "Adult" and "Parent" stimulus to the same Students. 2) A comparison of the differences in student response to the communication method according to the student′s grade, age, sex and level in school.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.73-80
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• 1995

The uses of stage-storage curve function are diverse in irrigation reservoirs. The curve functions would be used to determine the optimal size of spillway length and the inundation area above full water level based on the flood routing in reservoirs. In addition, the curve function would he used to transform the stage to the storage for the reservoir water management, in which the storage is the supply water. Besides those, the curve is necessary for the planning of dredging, the estimation of the effective and the dead storage, the drought management by reservoir, etc. The curve function data, however, are almost unavailable for these purposes. According to the statistics, about 74% of the 2, 900 resevoirs which are maintained by Farm Land Improvement Association have no more effective data. Therefore, the simulation of the curve function could be better alternative. The curve functions were simulated derivating the regression equations based on the basin relief ratio and the effective depth. The results of the verification show the enough reliability of the application to generate the curve function in some reservoirs which do not have the surveyed stage-storage data. Also, even though the averaged curve function would be applicated without the basin relief ratio data, the result shows that the simulated curve is closer to the real one than the linear function by only the existing effective storage data.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.51-59
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• 2018

It is difficult to determine the outdoor toxic level of hazardous chemicals that are leaked in the building, since there are no efficient ways to calculate how much percentage of the leaked chemicals is released into the outdoor atmosphere. In address to these problems, we propose a reasonable box model that can quantitatively evaluate the mass rate of the indoor chlorine leakage into the outside of the building. The proposed method assumes that the indoor chlorine leakage is fully mixed with the indoor air, and then the mixture of the chlorine and indoor air is exfiltrated into the outside of the building through effective leakage areas of the building. It is found that the exfiltration rate of the mixture of the chlorine and indoor air is strongly dependent on the temperature difference between inside and outside the building than the atmospheric wind speed. As compared with a conventional method that uses a vague mitigation factor, our method is more effective to evaluate the outdoor toxic threat zone of the chlorine that are leaked in the building, because it can consider the degree of airtight of the building in the evaluation of the threat zone.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.609-616
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• 2008

The present study is concerned with a simple numerical method for estimating the hindered settling velocity of noncolloidal suspensions with bidisperse size distribution of particles. The method is based on an effective-medium theory which uses the conditional ensemble averages for describing the velocity fields or other physical quantities of interest in the suspension system with the particles randomly placed. The effective-medium theory originally developed by Acrivos and Chang[1] for monodisperse suspensions is modified for the bidisperse case. Using the radial distribution functions and stream functions the hindered settling velocity of the suspended particles is calculated numerically. The predictions by the present method are compared with the previous experimental results by Davis and Birdsell[2] and Cheung et al.[3]. It is shown that the estimations by the effective-medium model of the present study reasonably agree with the experimental results.

• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.929-944
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• 2009

The present study is concerned with the extension of the Effective Convectivity Model (ECM) to the phase-change problem to simulate the dynamics of the melt pool formation in a Light Water Reactor (LWR) lower plenum during hypothetical severe accident progression. The ECM uses heat transfer characteristic velocities to describe turbulent natural convection of a melt pool. The simple approach of the ECM method allows implementing different models of the characteristic velocity in a mushy zone for non-eutectic mixtures. The Phase-change ECM (PECM) was examined using three models of the characteristic velocities in a mushy zone and its performance was compared. The PECM was validated using a dual-tier approach, namely validations against existing experimental data (the SIMECO experiment) and validations against results obtained from Computational Fluid Dynamics (CFD) simulations. The results predicted by the PECM implementing the linear dependency of mushy-zone characteristic velocity on fluid fraction are well agreed with the experimental correlation and CFD simulation results. The PECM was applied to simulation of melt pool formation heat transfer in a Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) lower plenum. The study suggests that the PECM is an adequate and effective tool to compute the dynamics of core melt pool formation.