• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.688-696
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• 1999

Changes in quality during frozen storage of meat with thermal equalized freezing and various freezing methods were investigated. When beef were frozen at freezing rate of $0.39{\sim}0.66\;cm/h$, average diameter of ice crystal were about $30{\sim}50\;{\mu}m$ and showed broken tissues or irregular cracks. At freezing velocity of $1.14{\sim}2.26\;cm/h$, ice crystals of about $10{\sim}30\;{\mu}m$ was formed mainly inside or between fiber and slight destruction of tissues was occurred. The average diameter (D) of the ice crystals were related to the characteristic freezing time $(t_c)$ by the equation: $D({\mu}m)=4.089+26.88logt_c\;(r^2=0.913)$. Beef with still-air freezing showed higher drip loss than methods of immersion and thermal equalized freezing. Also, drip loss of pork was relatively lower than beef and showed highest value to 7.39% during storage on 40 days at air-blast freezing method. No apparent change of pH during storage of frozen beef and pork by freezing methods were detected. However, least changes for sample with thermal equalized freezing was found compare to sample with still-air and air blast freezing in VBN and TBA value. The fluctuation of frozen storage temperature did not cause noticeable changes on pH and water content. However, drip loss, VBN and TBA values were increased slowly as frequency of fluctuation increased.

• Journal of the Korean Society of School Health
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• v.19 no.1
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• pp.79-88
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• 2006

Purpose : To identify general characteristics of school personnel with recent fatigue which was the most frequent symptom among subjective symptoms and to explore fatigue-related factors by evaluating physical and perceived health status, life style, and symptoms through data mining techniques. Methods : We collected a data of the 1,147(male 545, female 602) who were elementary, middle, or high school personnel, answered a questionnaire, and received physical examination in Seoul School Health Center from September to November in 2000. And we investigated the differences between fatigue group and non-fatigue group for demographic characteristics, physical health status, perceived health status, symptoms, and laboratory values by frequency, chi-square test, t-test, or simple logistic regression analysis by SAS package 8.1, and then selected significant variables as input variables of a decision tree analysis of CART model by SAS E-miner. Results : In general characteristics, the fatigue consisted of 41.1%(male 35.2%, female 46.4%) among 1,147 school personnel. In classical statistics, factors related with fatigue were female, lower means of systolic and diastolic pressure, young age, personnel in middle school, irregular eating habit, no exercise a week or less than 30minutes exercise a day, perception of unhealthy status, and subjective symptoms including short of breath at exercise. In simple logistic regression to examine the relationship between selected independent variables and fatigue as a dependent variable, the odds ratio of gender (female vs male) was 1.58 times, and young age ( 20s vs 60s) 20.67 times, and middle vs high school personnel 1.86 times. However, we mined combined several characteristics by SAS-E miner. In CART model, if health perception was healthy, and age was >= 37.5 years, the proportion of the fatigue was only 19.3%. but if health perception was not healthy and symptom was severe 'short of breath' during exercise and age was < 53.5 years, and BMI was >= 22.69, the proportion of the fatigue was up to 84.8%. Conclusions : The fatigue consisted of 41.1%(male 35.2%, female 46.4%). In classical statistics, fatigue-related factors among school personnel were young age, female gender, perceived unhealthy status, subjective physical symptoms, poor life-style, and lower blood pressure rather than only physical health status. However, in data mining, if health perception was healthy and age was >= 37.5 years, the proportion of the fatigue was only 19.3%. but if health perception was not healthy and symptom was severe 'short of breath' during exercise and age was < 53.5 years, and BMI was >= 22.69, the proportion of the fatigue was up to 84.8%.

• Journal of the Korean Dietetic Association
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• v.10 no.4
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• pp.407-416
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• 2004

The purpose of this study was to examine the comparison of growth development, bone mineral density and nutrient intakes between double income families' preschool children(DIFPC) and full-time housewives' preschool children(FHPC). Subjects were 111 preschool children. Anthropometric characteristics and bone mineral density in right forearm were measured. The questionnaire was composed of health status, life style, dietary behaviors, and dietary intakes and was completed by the children's mothers. The average age of the DIFPC(n=60) was 53.02 months and that of the FHPC(n=51) was 54.80 months. The birth height and weight of the subjects were 50.47㎝ and 3.27㎏ for DIFPC and 50.85㎝ and 3.36㎏ for FHPC, respectively. The average height, weight, % body fat, and obesity index were 108.50㎝, 18.35㎏, 15.35%, 96.71% in DIFPC and 111.46㎝, 19.64㎏, 16.80%, 97.31% in FHPC, respectively. The bone mineral density in forearm of two groups were 0.24g/㎠ in all. The infant feeding method was significantly different between DIFPC and FHPC; 58.9% of DIFPC was fed formula, while 44.4% of FHPC was fed breast milk(p<0.05). Proportions of children for their regular meal were 59.4%, 89.6%, and 61.0% for breakfast, lunch, and dinner, respectively. The major reasons for irregular meal were lack of time and poor appetite for breakfast and snacks for lunch and dinner. Most of the children answered they have snack over once a day, and 60.0% have unbalanced diet. The intakes of energy, calcium, iron, zinc, vitamin A, vitamin B1, niacin, and vitamin C did not meet the Korean RDAs. The intakes of K and vitamin A for DIFPC were significantly higher than those of FHPC(p<0.05, p<0.05). In conclusion, double income families' preschool children more have a low frequency of breast feeding and low intakes of micro nutrients, such as K and vitamin A than full-time housewives' ones.

• Korean Security Journal
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• no.53
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• pp.161-184
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• 2017

In general, security employees are more vulnerable to the risk of various incidents and accidents due to the specificity of their work, and they are less exposed to job satisfaction due to irregular working hours such as night shifts and physical labor. There is a concern that conflicts over turnover will be intensified. Therefore, companies should pay attention to job satisfaction, organizational commitment and turnover intention through effective human resource management of security employees who have influence on company's profit creation, so that companies should strive for competitiveness and development. The purpose of this study is to investigate the effect of casino security employee's job satisfaction on organizational commitment and turnover intentions in a questionnaire survey of security employees at Grand Korea Leisure Corporation. Frequency analysis, factor analysis, reliability analysis and multiple regression analysis were performed using SPSS 24.0. As a result of this study, it can be concluded that the higher the job satisfaction of the public enterprise security workers, the higher the organizational commitment and the lower the turnover intention. Therefore, if the company has competitiveness through effective human resource management that affects the wage satisfaction, promotion satisfaction, boss satisfaction and turnover intention affecting the organizational commitment, This study can be applied in the sense that it is possible to give.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.6
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• pp.529-541
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• 2004

This study was carried out to survey the eating behaviors and the food preferences of the tourism transportation business managers in Daegu areas by age. The survey was performed from 17 to August 25, 2003 by questionnaires and the subjects were 365 males. As a general factor, the subjects of survey were male drivers in their thirties to sixties. Their education level was middle school(44.9%) and high school(45.8%) diploma. This study showed that the managers eat three meals per day with high percentage(75.9%) and a large number of managers(24.1%) eat two meals only. 77.8% of the subjects responded that their diet life were irregular due to the property of their job. Frequency of eating-out turned out to be much higher in managers aged 60 over(p<0.001). They considered taste of the food firstly, and the prices of the food secondly, but the nutritional value of the food was considered with a low percentage(22.7%). We found that their BMI were overweight from 23.5 to 26.01, their calorie and some nutrient intakes were below their RDA. The most insufficiently consumed nutrient(less than 75% of RDA) was vitamin B₂ followed by calcium. The food preferences of subjects showed that the managers preferred boiled rice to any other rice as a staple foods. Their favorite menu of one-course Korean style meal turned out to be the bibimbob(boiled rice mixed with assorted vegetable and meat). As for subsidiary foods, out of all various meat soups, beef soups and beef-rib soups were most preferred. The most preferred stew were soybean paste stew and kimchi stew, and the most preferred cooked vegetables were cooked spinach, seasoned cucumber. Baechu kimchi(white cabbage kimchi) were the most preferred kind of kimchi. For desserts there was a very high preference for the watermelons, apples, and pears. For beverages the most preferred were ginseng tea, fruit juices and dietary fiber drinks. From the results listed above, the nutritional education needed to be done to the tourism transportation business managers to set the proper menu considering the characteristics of the preference each age group of managers.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.655-666
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• 2013

Lately, intensity and frequency of natural disasters such as flood are increasing because of abnormal climate. Casualties and property damages due to large-scale floods such as Typhoon Rusa in 2002 and Typhoon Maemi in 2003 rapidly increased, and these show the limits of the existing disaster prevention measures and flood forecasting systems regarding irregular climate changes. In order to efficiently respond to extraordinary flood, it is important to provide effective countermeasures through an inundation model that can accurately simulate flood inundation patterns. However, the existing flood inundation analysis model has problems such as excessive take of analysis time and accuracy of the analyzed results. Therefore, this study conducted a flood inundation analysis by using the Gerris flow solver that uses quadtree grid, targeting the Baeksan Levee in the Nakdong River Basin that collapsed because of a concentrated torrential rainfall in August, 2002. Through comparisons with the FLUMEN model that uses unstructured grid among the existing flood inundation models and the actual flooded areas, it determined the applicability and efficiency of the quadtree grid-based flood inundation model of the Gerris flow solver.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.1-8
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• 2010

The Fourier series uses a vibrating wave that possesses an amplitude that is like the one of the sine curve. Therefore, the functions used in the Fourier series do not change due to the value of the frequency and that set a limit to express irregular signals with rapid oscillations or with discontinuities in localized regions. However, the wavelet series analysis(WSA) method supplements these limits of the Fourier series by a linear combination of a suitable number of wavelets. By using the wavelet that is focused on time, it is able to give changes to the range in the cycle. Also, this enables to express a signal more efficiently that has singular configuration and that is flowing. The main objective of this study is to propose a scheme called wavelet series analysis for the application of wavelet theory to one-dimensional problems represented by the second-order elliptic equation and to evaluate theperformance of proposed scheme comparing with the finite element analysis. After a through evaluation of different types of wavelets, the HAT wavelet system is chosen as a wavelet function as well as a scaling function. It can be stated that the WSA method is as efficient as the FEA method in the case of axial bars with distributed loads, but the WSA method is more accurate than the FEA method at the singular points and its computation time is less.

• Journal of Periodontal and Implant Science
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• v.27 no.3
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• pp.495-514
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• 1997

The purpose of this study was to evaluate the in vitro effects of Nd:YAG laser irradiation on removal of a root surface smear layer after root planing in comparison with Tetracycline HCl. The 60 extracted human teeth due to severe periodontal disease were vigorously scaled and root planed with Gracey curet. Thirty specimen($5{\times}5{\times}2mm$) were obtained from root planed surface of 30 human teeth and assigned randomly to one of three groups : root planed group(5 specimen), Tetracycline HCI group(5 specimen, burnished for 5 minutes), and Nd:YAG laser group(25 specimen, German Dental Laser, Fotona Twinlight). Nd:YAG laser group was divided into 4 subgroups according to power of 1W, 1.5W, 2W, 3W at frequency to 10Hz. The specimen were then fixed, and examed by Scanning electron microscopic study. 30 of 60 human teeth used to measurement of the intrapulpal temperature rise during laser irradiation. Laser-irradiated surface exhibited various surface texture from relative flat surface to irregular surface with patent dentinal tubules of various shape and size. In some area, the root surface alteration which are carbonization, pit and crater formation and melting and resolidification were observed. The number of exposed dentinal tubules per unit($100_{\mu}m^2$) on tetracycline HCI group was more than that in the laser group below 1.5W of power(150mJ/pulse) and was significantly less than that in laser group above 2W of power(200mJ/pulse)(P<0.OOl). As power increased the intrapulpal temperature rise also increased. The result suggested that the parameter which effectively remove root surface smear layer than tetracycline HCI may cause thermal damage to pulp and root surface alteration result from laser exposure would indicate need for additional instrumentation. Thus, Nd:YAG laser irradiation in these parameter may not be appropriate for clinical use as adjunct to conventional periodontal therapy.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.114-122
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• 2015

In the high convective gas flow condition, irregular shaped water waves from which droplet entrainment occurs are generated under horizontally stratified two-phase flow condition. KAERI proposed a new mechanistic droplet entrainment model based on the momentum balance equation consisting of the shear stress, surface tension, and gravity forces. However, this model requires correlation or experimental data of several physical parameters related to the wave characteristics. In the present study, we tried to measure the physical parameters such as wave slope, wave hypotenuse length, wave velocity, wave frequency, and wavelength experimentally. For this, an experiment was conducted in the horizontal rectangular channel of which width, height, and length are, respectively, 40 mm, 50 mm, and 4.2 m. In the present test, the working fluids are chosen as air and water. The PIV technique was applied not only to obtain images for phase interface waves but also to measure the velocity field of the water flow. Additionally, we developed the parallel wire conductance probe for the confirmation of wave height from PIV image. Finally, we measured the physical parameters to be used in the validation of new droplet entrainment model.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.191-201
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• 2002

The Gubong gold-silver deposits if gold-silver-bearing hydrothermal massive quartz veins which were filled the fractures along fault shear (NE, NW) zones within Precambrian banded or granitic gneiss of Gyeonggi massif. Ore mineralization of this deposits is contained within a single stage of quartz vein which was formed by multiple episodes of fracturing and healing. Ore minerals are comported mainly of arsenopyrite, pyrite, sphalerite, chalcopyrite, galena with minor amounts of pyrrhotite, marcasite and electrum. The frequency and volume percentages of electrum associated with ore minerals from this deposits are recognized as follows; 44.5% and 54.3% with arsenopyrite, 24.3% and 33.8% with quartz, 12.6% and 0.1% with pyrite, 11.0% and 4.8% with galena, 5.0% and 7.0% with sphalerite and 2.5% and 0.02% with chalcopyrite, respectively. They show irregular (41.6%), subround (34.7%), elongate (17.0%) and granular (6.6%) shapes, respectively. Their grain size ranges from 2 to 150 um, but 90.9 percent of the grains are below 30 um. The chemical composition of electrums ranges from 26.39 to 72.51 Au atomic %. These composition (Au atomic %) on the basis of associated minerals are from 44.97 to 71.75 with arsenopyrite, pyrite, sphalerite and quartz, from 44.37 to 72.51 with quartz, from 35.40 to 41.01 with sphalerite and chalcopyrite, from 26.39 to 54.84 with pyrite, chalcopyrite, quartz and galena, from 28.49 to 53.28 with galena, respectively. We suggest that optimum recovery of gold would be obtained with reference to these results.