• Korean Journal of Soil Science and Fertilizer
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• v.26 no.2
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• pp.103-110
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• 1993

This study was made to evaluate the chemical properties of 481 farmers' orchard fields in An-Seong area. And the reasonable ferilizer rates were recommended utilizing the result of soil analysis. The results are summarized as follows : 1. As the soil fertility status of collected soil samples were evaluated on the basis of temporary optimal range for each soil chemical properties, 12.7 to 49.6% of the total 481 farmers' fields were range for soil improvement. 2. The contents of chemical component have a tendancy to decrease with depth gradually from surface to subsoil. 3. According to the relationship between the contents of soil component in subsoil and those in surface soil, the fertility condition of subsoil could be estimated on the basis of analysis data of surface soil. 4. The multiple regression equation for pear yield prediction to the organic matter and exchangable calcium contents in the soil were obtained. 5. Referring the average value, distribution ratio compared to the optimum level for each soil chemical properties and standard fertilizer rate, the soil fertility status could be categorized as "High" "Medium" and "Low". For each category, the recommended amounts for NPK and organic matter application were established. 6. The recommended rates through soul fertility diagnosis were less than farmer's dosage in the range 7.1~7.7 kg/10a for N, 0.8~11.5 kg/10a for $P_2O_5$, 7.1~19.9 kg/10a for $K_2O$ and 90~116 kg/10a for lime.

• The Journal of Korean Society for School & Community Health Education
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• v.8 no.1
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• pp.43-54
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• 2007

This study aimed at investigating the level of high school students' entrance exam stress and mental health first and also investigating if the entrance exam stress and mental health are related to gender, grade, character type, parenting style and economic status. This is expected to be used as a fundamental data for the development of health education program on high school students' stress and diagnosis of their mental health. To achieve those goals above, the questionnaire was used and the sample consisted of 600 students from general high schools in a large city, C and in a smaller city, A in Chungnam province through questionnaire and the conclusion, which was based on 582 proper questionnaires from the 600 questionnaires, through variable analysis, correlation analysis and multi-regression, is below. First, according to the information provided by respondents, the result showed the relationship between those background variables and the entrance exam stress and mental health level. As the students are more introverted and the parenting style is more authoritative, the entrance exam stress is higher and the mental health level is higher as the parenting style is more authoritative and the economic status is lower. In gender, the entrance exam stress level was high for male students in regard to parents pressure. For female students, it was due to the insufficient free time. In test performance, the good grade group showed high stress level when they don't have enough free time and the poor grade group showed high stress level when they have test tension and poor test performance. In character style, the introverted group showed high stress level in future uncertainty. In parenting style, the authoritative group showed significantly high level in all four sub-factors and there is no significant relationship with the stress level and economic statue. Female students reported higher mental health level than male students in somatization and depression. In academic achievement, the poor grade group showed high level in obsession, fear-anxiety and psychotism. In character style, the introverted group showed high level in sensitivity towards others and depression. And in parenting style, the authoritative group is higher in 9 sub-factors than the other two groups in the factor, economic status. The lower economic status group showed high mental health problem level in this order; in obsession, sensitivity towards others, depression, paranonia and psychotism. Second, the results revealed that there is a significant difference among the groups after comparing and analyzing the relationship between the mental health level according to the three groups, the first, second and third group divided by the degree of entrance exam stress. And the higher the entrance exam stress is, the higher the mental health problem level is. Verification showed that there was obvious difference among the groups. the entrance exam stress was positively correlated with the mental health level. The lack of free time, future uncertainty, test anxiety/poor test performance and parents pressure, these factors, in that order, were correlated with the mental health level. when the prediction variables which influenced on mental health are analyzed, test-anxiety/poor test performance was found to be related to mental health most. And after the factor, test-anxiety, future uncertainty and the lack of free time were listed(ranked), however results did not show any correlation with parents' pressure.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.80-87
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• 2010

This study was conducted to develop a reservoir modelling workflow to reproduce the heterogeneous distribution of effective permeability that impacts on the performance of SAGD (Steam Assisted Gravity Drainage), the in-situ bitumen recovery technique in the Athabasca Oil Sands. Lithologic facies distribution is the main cause of the heterogeneity in bitumen reservoirs in the study area. The target formation consists of sand with mudstone facies in a fluvial-to-estuary channel system, where the mudstone interrupts fluid flow and reduces effective permeability. In this study, the lithologic facies is classified into three classes having different characteristics of effective permeability, depending on the shapes of mudstones. The reservoir modelling workflow of this study consists of two main modules; facies modelling and permeability modelling. The facies modelling provides an identification of the three lithologic facies, using a stochastic approach, which mainly control the effective permeability. The permeability modelling populates mudstone volume fraction first, then transforms it into effective permeability. A series of flow simulations applied to mini-models of the lithologic facies obtains the transformation functions of the mudstone volume fraction into the effective permeability. Seismic data contribute to the facies modelling via providing prior probability of facies, which is incorporated in the facies models by geostatistical techniques. In particular, this study employs a probabilistic neural network utilising multiple seismic attributes in facies prediction that improves the prior probability of facies. The result of using the improved prior probability in facies modelling is compared to the conventional method using a single seismic attribute to demonstrate the improvement in the facies discrimination. Using P-wave velocity in combination with density in the multiple seismic attributes is the essence of the improved facies discrimination. This paper also discusses sand matrix porosity that makes P-wave velocity differ between the different facies in the study area, where the sand matrix porosity is uniquely evaluated using log-derived porosity, P-wave velocity and photographically-predicted mudstone volume.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.313-327
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• 2013

In the study, three-dimensional geostatistical simulations on McMurray Formation which is the largest oil sand reservoir in Athabasca area, Canada were performed, and the optimal site for steam assisted gravity drainage (SAGD) was selected based on the predictions. In the selection, the factors related to the vertical extendibility of steam chamber were considered as the criteria for an optimal site. For the predictions, 110 borehole data acquired from the study area were analyzed in the Markovian transition probability (TP) framework and three-dimensional distributions of the composing media were predicted stochastically through an existing TP based geostatistical model. The potential of a specific medium at a position within the prediction domain was estimated from the ensemble probability based on the multiple realizations. From the ensemble map, the cumulative thickness of the permeable media (i.e. Breccia and Sand) was analyzed and the locations with the highest potential for SAGD applications were delineated. As a supportive criterion for an optimal SAGD site, mean vertical extension of a unit permeable media was also delineated through transition rate based computations. The mean vertical extension of a permeable media show rough agreement with the cumulative thickness in their general distribution. However, the distributions show distinctive disagreement at a few locations where the cumulative thickness was higher due to highly alternating juxtaposition of the permeable and the less permeable media. This observation implies that the cumulative thickness alone may not be a sufficient criterion for an optimal SAGD site and the mean vertical extension of the permeable media needs to be jointly considered for the sound selections.

• Korean Journal of Environment and Ecology
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• v.31 no.4
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• pp.381-396
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• 2017

Understanding species distribution plays an important role in conservation as well as evolutionary biology. In this study, we applied a species distribution model to predict hotspot areas and habitat characteristics for endangered herpetofauna species in South Korea: the Korean Crevice Salamander (Karsenia koreana), Suweon-tree frog (Hyla suweonensis), Gold-spotted pond frog (Pelophylax chosenicus), Narrow-mouthed toad (Kaloula borealis), Korean ratsnake (Elaphe schrenckii), Mongolian racerunner (Eremias argus), Reeve's turtle (Mauremys reevesii) and Soft-shelled turtle (Pelodiscus sinensis). The Kori salamander (Hynobius yangi) and Black-headed snake (Sibynophis chinensis) were excluded from the analysis due to insufficient sample size. The results showed that the altitude was the most important environmental variable for their distribution, and the altitude at which these species were distributed correlated with the climate of that region. The predicted distribution area derived from the species distribution modelling adequately reflected the observation site used in this study as well as those reported in preceding studies. The average AUC value of the eigh species was relatively high ($0.845{\pm}0.08$), while the average omission rate value was relatively low ($0.087{\pm}0.01$). Therefore, the species overlaying model created for the endangered species is considered successful. When merging the distribution models, it was shown that five species shared their habitats in the coastal areas of Gyeonggi-do and Chungcheongnam-do, which are the western regions of the Korean Peninsula. Therefore, we suggest that protection should be a high priority in these area, and our overall results may serve as essential and fundamental data for the conservation of endangered amphibian and reptiles in Korea.

• Journal of dental hygiene science
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• v.7 no.4
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• pp.251-256
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• 2007

The purpose of this study was to examine what induced dental hygienists to take up another employment and whether their job satisfaction had anything to do with it in an attempt to help curtail their turnover rate. The subjects in this study were approximately 200 dental hygienists who worked in dental institutions. A survey was conducted from July 24 through September 24, 2006, by using structured, self-administered questionnaires. For data analysis, SPSS 11.5 program was employed to see if their turnover experience was linked to their general characteristics, why they took up another employment, how long they wanted to do that and how their job satisfaction was related to that. The findings of the study were as follows: 1. In regard to turnover experience by age, marital status and career, those who had ever changed their employment accounted for 36.2 percent of the age group from 24 to 26, 83.0 percent of the unmarried ones and 50.0 percent of those whose career was less than one to three years (p < 0.001). By monthly mean income, 50.0 percent of the dental hygienists whose monthly mean income ranged from 1.0 to 1.29 million won had that experience(p < 0.05). The gap between these groups and the others was statistically significant. 2. As for the reason of turnover, working environments were cited most often(28.1%), followed by possibilities(18.0%), relationship with supervisors and colleagues(12.4%), and compensation(4.5%). 3. Concerning a preferred new workplace, 66.2 percent of the dental hygienists who worked in dentist's offices hoped to be newly hired by public dental clinics(p < 0.001). By education, 64.3 percent of the college-educated dental hygienists wanted to work at public dental clinics as well(p < 0.01). 4. The change of employment was under the greatest influence of the possibilities of workplace, followed by workload, pay and relationship with colleagues. All the factors had a negative impact on their turnover. Those who were less satisfied sought new employment more often, and job satisfaction made a statistically significant difference to that. The job satisfaction factors made a prediction of their turnover intention ($R^2=.254$).

• Journal of Radiation Protection and Research
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• v.8 no.1
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• pp.1-14
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• 1983

For the purpose of prediction and protection of radiation effects on the Korean people, we have collected autoptic data from the National Institute of Scientific Investigation. The mass of organs and the size of brains measured is analysed for 1,921 Korean people. The results obtained are as follows; 1. The weight of the kidney in the Reference Korean is 251.6g in male and 227.7g in female. 2. The weight of the lung in the Reference Korean is 1,204.4g in male and 957.4g in female. 3. The weight of the heart in the Reference Korean is 348.8g in male and 301.6g in female. 4. The weight of the liver in the Reference Korean is 1,863.9g in male and 1,610.9g in female. 5. The weight of the pancreas in the Reference Korean is 56.4g in male and 54.0g in female. ,6. The weight of the spleen in the Reference Korean is 67.3g in male and 58.2g in female. 7. The anteroposterior diameter, transverse diameter and vertical diameter of the brain in the Reference Korean are 17.6cm, 15.5cm and 8.6cm in male, respectively, and 17.7cm, 15.4cm and 8.2cm in female, respectively.

• Journal of Food Hygiene and Safety
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• v.24 no.3
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• pp.232-237
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• 2009

This study was conducted to develop a model for describing the effect of storage temperature (4, 10, 15, 20, 25, 30 and $35^{\circ}C$) on the growth of Escherichia coli O157 : H7 in ready-to-eat (RTE) lettuce treated with or without (control) alkaline electrolyzed water (AIEW). The growth curves were well fitted with the Gompertz equation, which was used to determine the specific growth rate (SGR) and lag time (LT) of E. coli O157 : H7 ($R^2$ = 0.994). Results showed that the obtained SGR and LT were dependent on the storage temperature. The growth rate increased with increasing temperature from 4 to $35^{\circ}C$. The square root models were used to evaluate the effect of storage temperature on the growth of E. coli O157 : H7 in lettuce samples treated without or with AIEW. The coefficient of determination ($R^2$), adjusted determination coefficient ($R^2_{Adj}$), and mean square error (MSE) were employed to validate the established models. It showed that $R^2$ and $R^_{Adj}$ were close to 1 (> 0.93), and MSE calculated from models of untreated and treated lettuce were 0.031 and 0.025, respectively. The results demonstrated that the overall predictions of the growth of E. coli O157: H7 agreed with the observed data.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.41-47
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• 2016

Background: For the accurate dose assessment in radiation therapy, energy spectrum of the photon beam generated from the linac head is essential. The aim of this study is to develop the technique to accurately unfolding the energy spectrum with the transmission analysis method. Materials and Methods: Clinical linear accelerator and Monet Carlo method was employed to evaluate the transmission signals according to the thickness of the observer material, and then the response function of the ion chamber response was determined with the mono energy beam. Finally the energy spectrum was unfolded with HEPROW program. Elekta Synergy Flatform and Geant4 tool kits was used in this study. Results and Discussion: In the comparison between calculated and measured transmission signals using aluminum alloy as an attenuator, root mean squared error was 0.43%. In the comparison between unfolded spectrum using HEPROW program and calculated spectrum using Geant4, the difference of peak and mean energy were 0.066 and 0.03 MeV, respectively. However, for the accurate prediction of the energy spectrum, additional experiment with various type of material and improvement of the unfolding program is required. Conclusion: In this research, it is demonstrated that unfolding spectra technique could be used in megavoltage photon beam with aluminum alloy and HEPROW program.

• Sleep Medicine and Psychophysiology
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• v.24 no.1
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• pp.38-45
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• 2017

Objectives: Sleep disturbance is a very rapidly growing disease with aging. The purpose of this study was to investigate the prevalence of sleep disturbances and its predictive factors in a three-year cohort study of people aged 60 years and over in Korea. Methods: In 2012 and 2014, we obtained data from a survey of the Korean Social Life, Health, and Aging Project. We asked participants if they had been diagnosed with stroke, myocardial infarction, angina pectoris, arthritis, pulmonary tuberculosis, asthma, cataract, glaucoma, hepatitis B, urinary incontinence, prostate hypertrophy, cancer, osteoporosis, hypertension, diabetes, hyperlipidemia, or metabolic syndrome. Cognitive function was assessed using the Mini-Mental State Examination for dementia screening in 2012, and depression was assessed using the Center for Epidemiologic Studies Depression Scale in 2012 and 2014. In 2015, a structured clinical interview for Axis I psychiatric disorders was administered to 235 people, and sleep disturbance was assessed using the Pittsburgh Sleep Quality Index. The perceived stress scale and the State-trait Anger Expression Inventory were also administered. Logistic regression analysis was used to predict sleep disturbance by gender, age, education, depression score, number of coexisting diseases in 2012 and 2014, current anger score, and perceived stress score. Results: Twenty-seven percent of the participants had sleep disturbances. Logistic regression analysis showed that the number of medical diseases three years ago, the depression score one year ago, and the current perceived stress significantly predicted sleep disturbances. Conclusion: Comorbid medical disease three years previous and depressive symptoms evaluated one year previous were predictive of current sleep disturbances. Further studies are needed to determine whether treatment of medical disease and depressive symptoms can improve sleep disturbances.