• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.269-275
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• 2013

Purpose: The aim of this retrospective study was to evaluate the influence of implant diameter, length and placement to implant stability. Materials and methods: Total 90 implants (US II plus$^{TM}$, Osstem co, Busan, Korea) of 72 patients were determined as experimental samples. The factors of diameters(${\phi}$ 4 mm, ${\phi}$ 5 mm), lengths (10 mm, 11.5 mm, 13 mm), and implant placement (maxilla, mandible) were analyzed. The stability of the implants was measured by resonance frequency analysis (RFA) at the time of implant placement and impression taking. The difference of ISQ values according to patient's gender was evaluated by Independent t-test. ISQ values were compared between implant diameter, length and placement using one-way ANOVA and Tukey HSD test (${\alpha}=.05$). To compare ISQ values between at the time of surgery and impression taking, paired t-tests were used (${\alpha}=.05$). Results: The change of implant length did not show significant different on the ISQ value (P>.05). However, 5 mm diameter implants had higher ISQ values than 4 mm diameter implants (P<.05). Implants placed on the mandible showed significantly higher ISQ values than on the maxilla (P<.05). Conclusion: In order to increase implant stability, it is better to select the wider implant, and implants placed on mandible are possible to get higher stability than maxilla. ISQ values at impression taking showed higher implant stability than ISQ values at implant placement, it means that RFA is clinically effective method to evaluate the change of implant stability through the osseointegration. The consideration of the factors which may affect to the implant stability will help to determine the time of load applying and increase the implant success rate.

• Korean journal of food and cookery science
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• v.18 no.6
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• pp.704-715
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• 2002

This study intended to compare dietary and snack habits of primary students in the schools providing and non-providing lunch to clarify the correlation between those conditions and the occurrence of dental caries. Furthermore, this study also focused on evaluating educational effects by providing children with nutritional education program. 1. As a result of dietary habit analysis, it was found that children from the school providing lunch were better in terms of breakfast regularity, eating speed. optimum amount of intake, and meal time regularity than those from the school non-providing lunch. In particular, it was noted that children from the school providing lunch took a little more meat, fish, seaweed and milk or dairy products than those from school non-providing lunch. Thus, it could be assumed hat children provided with lunch have more reasonable dietary habit than those without lunch program. In general, it was found that there was a slight positive change in children's dietary habit after nutritional instruction than before, suggesting that the nutritional education had effects on improving their dietary habit. 2. It was found that primary students often took snacks causing dental caries such as caramel, chocolate, sweets and biscuits, and children from the school providing lunch were more willing to reduce those snacks upon recognizing the causes of dental caries than those from the school non-providing lunch. For the children who chewed gum with physical cleansing effects, it was shown that the highest frequency wat twice or three times a week. Moreover, the ratio of children who took snacks following dinner which might affect their dental caries and the ratio of children who selected snacks because of TV commercial were both reduced after nutritional education. Also the consumption of detergent foods like vegetable, fruit, protein. seaweed. milk or dietary products after nutritional education was increased. 3. It was found that children from the school providing lunch took more often all food groups except for food group IV affecting dental caries than those from the school non-providing lunch. The average number of consuming foods which cause dental caries was 5.04 times per person a day, and most of those were rather taken by liquid than solid food. The average eating times of rinsing foods which kill the bacteria on the surface of teeth and prevent from dental caries, was 9.33 for a person a day, which was a little higher than recommended time. Exposed time for dental caries for a person a day was 100.9 min, of which liquid dental caries was 56.2 min and solid dental caries was 44.6 min, suggesting that liquid food had a high potential to cause dental caries.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.708-722
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• 2010

This study was carried out to classify vegetation structure of the Hyangjeokbong in the Deogyusan National Park using the gradient analysis and phytosociological method. The vegetation was classified into Quercus mongolica community(Rhododendron schlippenbachii subcommunity, typical subcommunity), Q. serrata community, Q. variabillis community, Pinus densiflora community, Cornus controversa community, Fraxinus mandshurica community and Taxus cuspidata community. Ecological characteristics such as species composition, layer structure, vegetation ratio, and the distribution of individual trees by DBH(diameter at breast height) were significantly different among communities. The order of important value of the forest community with DBH 2cm above plants was Q. mongolica(81.2), F. mandshurica, Q. serrata, P. densiflora, Acer pseudosieboldianum, Q. variabillis, Rhododendron schlippenbachii, C. controversa, T. cuspidata. Distribution of DBH of Q. mongolica and Q. serrata had suggesting a continuous domination of these species over the other species for the time being. In contrast, F. mandshurica appeared limited to the valley of the sheet and a higher frequency of young individuals, suggesting a continuous domination of these species the development of a climax forest terrain. P. densiflora and T. cuspidata had suggesting a continuous domination of these species over the other species for the time being in maintain. Q. variabilis and C. controversa had a formality distribution, suggesting a continuous domination of these species over the other species for the time being. This study examined the correlation between each community and the environment according to DCCA ordination. The Q. mongolica community and T. cuspidata community predominated in the highest elevation habitats which had few moisture, Ca and in the low pH. The Q. serrata community mainly occurred in the low elevation habitats which had many moisture. P. densiflora community predominated in the middle elevation and south-facing slope habitats which had few moisture, Ca and in the low pH. F. mandshurica community predominated in the low elevation habitats which had many moisture, Ca and pH.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.4
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• pp.211-219
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• 2006

The UET(ultrasound excited thermography) for the ,eat-time diagnostics of the object employs an infrared camera to image defects of the surface and subsurface which are locally heated using high-frequency putted ultrasonic excitation. The dissipation of high-power ultrasonic energy around the feces of the defects causes an increase In temperature. The defect's image appears as a hot spot (bright IR source) within a dark background field. The UET for nondestructive diagnostic and evaluation is based on the image analysis of the hot spot as a local response to ultrasonic excited heat deposition. In this paper the applicability of VET for fast imaging of defect is described. The ultrasonic energy is injected into the sample through a transducer in the vertical and horizontal directions respectively. The voltage applied to the transducer is measured by digital oscilloscope, and the waveform are compared. Measurements were performed on four kinds of materials: SUS fatigue crack specimen(thickness 14mm), PCB plate(1.8 mm), CFRP plate(3 mm) and Inconel 600 plate (1 mm). A high power ultrasonic energy with pulse durations of 250ms Is injected into the samples in the horizontal and vertical directions respectively The obtained experimental result reveals that the dissipation loss of the ultrasonic energy In the vertical injection is less than that in the horizontal direction. In the cafe or PCB, CFRP, the size of hot spot in the vortical injection if larger than that in horizontal direction. Duration time of the hot spot in the vertical direction is three times as long as that in the horizontal direction. In the case of Inconel 600 plate and SUS sample, the hot spot in the horizontal injection was detected faster than that in the vertical direction

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.577-587
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• 2021

Drought is generally considered to be a natural disaster caused by accumulated water shortages over a long period of time, taking months or years and slowly occurring. However, climate change has led to rapid changes in weather and environmental factors that directly affect agriculture, and extreme weather conditions have led to an increase in the frequency of rapidly developing droughts within weeks to months. This phenomenon is defined as 'Flash Drought', which is caused by an increase in surface temperature over a relatively short period of time and abnormally low and rapidly decreasing soil moisture. The detection and analysis of flash drought is essential because it has a significant impact on agriculture and natural ecosystems, and its impacts are associated with agricultural drought impacts. In South Korea, there is no clear definition of flash drought, so the purpose of this study is to identify and analyze its characteristics. In this study, flash drought detection condition was presented based on the satellite-derived drought index Evaporative Stress Index (ESI) from 2014 to 2018. ESI is used as an early warning indicator for rapidly-occurring flash drought a short period of time due to its similar relationship with reduced soil moisture content, lack of precipitation, increased evaporative demand due to low humidity, high temperature, and strong winds. The flash droughts were analyzed using hydrometeorological characteristics by comparing Standardized Precipitation Index (SPI), soil moisture, maximum temperature, relative humidity, wind speed, and precipitation. The correlation was analyzed based on the 8 weeks prior to the occurrence of the flash drought, and in most cases, a high correlation of 0.8(-0.8) or higher(lower) was expressed for ESI and SPI, soil moisture, and maximum temperature.

• Journal of Korea Water Resources Association
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• v.44 no.10
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• pp.797-807
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• 2011

Phenomenon of vegetation recruitment on the sand bar is drastically rising in the streams and rivers in Korea. In the 1960s prior to industrialization and urbanization, most of the streams were consisted of sands and gravels, what we call, 'White River'. Owing to dam construction, stream maintenance, etc. carried out since the '70s, the characteristic of flow duration and sediment transport have been disturbed resulting in the abundance of vegetation in the waterfront, that is, 'Green River' is under progress. This study purposed to identify the correlation among water level, water temperature, rainfall, soil moisture and soil texture out of the factors which give an effect on the vegetation recruitment on the sand bar of unregulated stream. To this purpose, this study selected the downstream of Naeseong Stream, one of sand rivers in Korea, as the river section for test and conducted the monitoring and analysis for 289 days. In addition, this study analyzed the aerial photos taken from 1970 to 2009 in order to identify the aged change in vegetation from the past to the present. The range of the tested river section was 361 m in transverse length and about 2 km in longitudinal length. According to the survey analysis, the tested river section in Naeseong Stream was a gaining river showing the higher underground-water level by 20~30 m compared to Stream water level. The difference in the underground water temperature was less than $5^{\circ}C$ by day and season and the Stream temperature did not fall to $10^{\circ}C$ and less from May when the vegetation germination begins in earnest. The impact factor on soil moisture was the underground water level in the lower layer and the rainfall in the upper layer and it was found that all the upper and lower layer were influenced by soil particle size. The soil from surface to 1 m-underground out of 6 soil moisture-measured points was sand with the $D_{50}$ size of 0.07~1.37 mm and it's assumed that the capillary height possible in the particle size would reach around 14~43 cm. On the other hand, according to the result of space analysis on the tested river section of unregulated stream for 40 years, it was found that the artificial disturbance and drought promoted the vegetation recruitment and the flooding resulted in the frequency extinction of vegetation communities. Even though the small and large scales of recruitment and extinction in vegetation have been repeated since 1970, the present vegetation area increased clearly compared to the past. It's found that the vegetation area is gradually increasing over time.

• The Journal of Korean Society for School & Community Health Education
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• v.17 no.1
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• pp.89-99
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• 2016

Objectives: This cross-sectional study aims to investigate the prevalence and factors relating to handwashing with soap among Korean adults. Methods: Study subjects consist of 755 adults who have been contacted in September 2013 via telephone surveys. The data collected has been analyzed using descriptive statistics, a chi-square test and a logistic regression analysis. A primary purpose is to understand the prevalence of handwashing with soap more than 8 times daily and for 30 seconds per wash among adults. Independent variables include socioeconomic levels, the participants' perception and knowledge of handwashing and their educational experiences relating to handwashing. Results: The overall percentile of people who wash their hands with soap 8 time per day for 30 seconds or more per wash was 16.0%, which is 121 people out of 755 study subjects. In univariate analysis, age, education levels, monthly average income, handwashing habits, perceptions relate to the importance of handwashing, self-assessment of handwashing, environment of public toilet, and the completion of handwashing education shows significant result. Significant differences also appear (p<0.05) in logistic regression analysis on binary variables. There is a strong correlation between daily frequency of handwashing and willingness to wash hands while outside. For example, people who wash their hands very often while outside are 2.24 times (95% C.I. 1.29-3.87) more likely to practice handwashing with soap 8 times per day for 30 seconds or more per wash than those people who only intermittently wash their hands while outside. Furthermore, people with general unwillingness to wash their hands while outside are 4.61 times (95% C.I. 1.22-3.28) less likely to practice handwashing with soap 8 times per day for 30 seconds or more per wash than those with general willingness. Conclusions: This study has been carried out to identify the decision factors in practicing handwashing with soap for Korean adults. In univariate analysis, age, education level, monthly average income, handwashing habits, handwashing self-assessment, public toilet environment, completion of handwashing education and so forth have been identified to be the decision factors. This study result shows that the overall level of cleanliness of public toilet perceives to be poor and it suggests that the environment of public toilet needs to be enhanced. As the handwashing habits and handwashing-self assessment have been identified to be the significant decision factors for handwashing, there search and approach in these factors need to be developed further.

• Journal of Korean Home Economics Education Association
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• v.23 no.3
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• pp.139-160
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• 2011

The purpose of this study is twofold: (i) to develop a teaching and learning plan and practical performance assessment tools for the improvement of teenager-parent communication and relationships as well as explore their effects on the communication in the everyday family life; and (ii) to find the underlying problems of teenager- parent communication through conversation analysis and to provide a improved dialogue model. We provided the experimental group with a performance task of communication training between teenagers and their parents in the real family situation while the control group practiced communication skills in a learning situation. However for both classes, before and after performance tasks were equally provided. The experimental group exhibited a longer conversation time with their parents, better communication skills, and higher degrees of relational satisfaction than the control group. Conversation analysis revealed that the experimental group reduced the use of blocking techniques in the teenager-parent conversations more than the control group, and all so raised the frequency of functional communications more than the control group. In both areas of communication in the experimental group was significantly improved, Most notably, a problem-solving case through no-lose conflict resolution methods was effective, succeeding by 70% in the e experimental group and 43.3% in the control group. Parents use blocking techniques like admonition, lecturing, blaming. sarcastic remarking, ordering and so forth, while teenagers use dispute, avoidance, blaming, and teasing in this order. The communication problems during the conversation process, teenagers' evasive and rebellious way of speaking instigates adverse communication responses from parents, so their conversation tends to unfold as ambiguous evasion opposed to: inquiring or evasion by short answers vs. ordering-preaching, or disputing vs. criticizing-making sarcastic, disputing vs. disputing-teaching, and criticizing vs. criticizing.

• The Journal of Korean Society for School & Community Health Education
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• v.3
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• pp.35-58
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• 2002

This research attempted to investigate the real state of adolescent smoking and drinking, and to study how stress influences on smoking and drinking of high school students. This data was collected from 837 first and second grade students in a vocational high school in Go-yang city, Gyeonggi province. Data analysis consisted of frequency, percentage, Chi-square, T-test, step-wise regression analysis, using SPSSWIN. The results of analysis were as follows: First, 51.7% of the students have never smoked, while 48.3% have experienced smoking. Most students started smoking in the second year of the middle school, though 17.6% of the smokers already started in the elementary school. The strongest motive of initial smoking was curiosity, next the inducement of friends, and 10.9% of them smoked to get rid of stress. Their favorite place for smoking was in the order of the entertainment centers, schools, and private academies. They personally purchased cigarettes mostly at the store. Most of them smoked less than 5 cigarettes a day, but 3.7% smoked more than a pack of cigarettes a day, usually with friends rather than alone. Second, the ratio of drinking was relatively high 78.1%, and their initial drinking experience was most frequent at the third year of the middle school. The initial motive of drinking was mostly curiosity and the inducement of friends, but 10.7% of them started drinking to reduce stress and anxiety. The places for buying alcohol and drinking were bars or restaurants. The ratio of habitual drinking was 45.1%, and the ratio of irregular drinking was 53.3%. 1.8% of the drinking students enjoyed drinking everyday. The amount of drinking varied from half a bottle to two bottles of Soju, and the drinking problem was serious to see that 11% of them drank more than two bottles at a time. Because 84.4% drank in groups with friends, a thorough and systematic supervision and education of the peer group drinking is essential. Third, as for the relationship between personal matters and smoking, it was found that there was a positive relation between smoking and sex, but there was no correlation between smoking and school years. Adolescent smoking was also related with scholastic achievement, the number of friends, and the existence of parents. Fourth, as for the relationship between personal matters and drinking, it was found that there was no correlation between drinking and sex, but there was a positive relation between drinking and school years. Fifth, the average index of stress was students themselves(2.58), school life(2.53), family life(2.19), friends(2.00), and the total index of stress was 2.33. Sixth, there appeared a marginal negative correlation between stress and 'drinking and smoking' in Pearson coefficient of correlation r to see the influence of stress on smoking and drinking. The difference of the average index of stress according to smoking and drinking bears meaningful difference for all students, smokers and non-smokers, drinkers and abstainers in students themselves, school life, family life, friends, and total stress. Smoking has an effect on family life most, school life next, and drinking has an effect on school life most, family life next, with the explanation power of 11% and 9% respectively, in a regression analysis to analyze the factors influencing on smoking and drinking among the factors of stress.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.2
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• pp.77-86
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• 2017

Selection of location in food service start-up business is sure to be a shortcut to achievement of business performance, and in this context, it's no exaggeration to say that food service industry is an real estate industry. This study looked into what influence of the location factor in food service start-up business had on sales performance, and intended to verify whether the location factors ultimately influenced business performance consequent on the influence of location factors on start-up business satisfaction. To this end, this study set food service owner-operators as its research subject, and conducted a survey of the operators (of restaurants) located in Anyang-si from December 1, 2016 until January 30, 2017. This study distributed a total of 300 copies of questionnaires, and collected 245 copes, among which this study used 198 copies for empirical study excluding the copies whose reply was unfaithful. This study did empirical analysis of 198 copies using SPSS 22.0 Statistical Package Program, together with the application of frequency analysis, factor analysis and regression analysis. The major results of this study are as follows: First, this study divided the location factors in food service start-up business stores into the four, i.e. accessibility, clustering property, placeness and visibility, etc. Second, the study results showed that accessibility, clustering property, placeness and visibility had significant influence as one in the influence of locational factors on sales performance. Third, this study could understand that start-up business satisfaction had a partial mediated effect in the influence of location factors on sales performance. Resultantly, this study confirmed food service start-up business's own selection of location, and wished to find major factors and a differentiated point in time of selection of location of stores in other fields. Such a result gives an implication that it's necessary to concentrate all efforts to increase sales performance of food service start-up business from the location selection phase, and to make efforts to increase start-up business satisfaction.