• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.169-179
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• 2003

Undrained shear strength of clay deposit is one of the most important properties in the design of geotechnical structures. The use of piezocone test is rapidly growing due to its merit that can measure the in-situ undrained shear strength continuously with less error. The reliability of the shear strength from piezocone test depends upon the cone factor applied. Many researchers have suggested different ranges of values for the factors. This study performs to find out the validity of the suggested values in Korea and their charateristics related to the mechanical properties of clay. Piezocone tests were performed at the site of pilot project of ground improvement at Yangsan-Mulgeum Gyeongnam to investigate the charateristics of piezocone factors. The piezocone fators$(N_{kt}, N_{ke}, N_{\Delta u})$ based on the undrained shear strength from quick triaxial compression test are generally within the suggested range. And there appears considerable relations between undrained shear strength and $(N_{kt}, N_{ke}, N_{\Delta u})$ and between preconsolidation pressure and $(N_{kt}, N_{ke})$, while plasticity index, rigidity index and friction ratio do not show any relations with cone factors. The results also reveal that factor $(N_{\Delta u})$ shows higher reliability than factors $(N_{kt} and N_{ke})$, which show smaller standard deviation, breadth of change and scattering.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.61-72
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• 2008

Leaf area index (LAI) is a key biophysical variable influencing land surface processes such as photosynthesis, transpiration and energy balance, and is a required input to estimate evapotranspiration in various ecological and hydrological models. The development of more correct and useful LAIs estimation techniques is required by these importance, but LAIs had been assumed in most LAI research through simple relations with the normalized difference vegetation index (NDVI) because the field measurement is difficult on wide area. This paper is to evaluate the MODIS LAI Product's practical use by comparing with LAIs that is derived from NOAA AVHRR NDVIs and the 2 years (2003-2004) measured LAIs of Korea Forest Research Institute in Gyeongancheon watershed (561.12 $Km^2$). As a result, the MODIS LAIs of deciduous forests showed higher values about 14 % and 15~30 % than the measured LAIs and NOAA LAIs. In the year of 2003, the MODIS LAIs in coniferous forests were 5 % higher than the measured LAIs, and showed about 7 % differences comparing with the NOAA LAIs except April. These differences come from the insufficient field data measured in partial points of the target area, and the extracted reference data from MODIS LAIs include the limits of spatial resolution and the error of incorrect land cover classification. Thus, using the MODIS data by the proper correction with the measured data can be useful as an input data for ecological and hydrological models which offers the vegetation information and simulates the water balance of a given watershed.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.426-438
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• 2009

The purpose of this study was to examine the relationship of the general characteristics of dental patients to their total O'Leary index and individual plaque indexes in a bid to check the oral hygiene state of citizens and evaluate their plaque management ability. The subjects in this study were 288 patients at dental hospitals and clinics in Busan and South Gyeongsang Province. A survey was conducted from September to November 2008. The findings of the study were as follows: 1. Overall, the O'Leary index of the patients investigated stood at 72 percent. By age and gender, the O'Leary index was highest among those in their 30s(83%) and among the women(75%)(p<.05). As to the influence of toothbrushing frequency, the patients who did it twice or more a day had the highest O'Leary index(75%)(p<.001). By the use of oral hygiene supplies, the patients who used oral hygiene supplies had a higher O'Leary index(76%) than the others who didn't(p<.01). 2. As for plaque index for each tooth, 28 percent of their teeth were given zero point, and 52 percent were given one mark. 13 percent were given two marks, and 6.3 percent were given three marks. Thus, the teeth that were given one mark were largest in number(p<.001). 3. As for plaque index for labial posterior mandibular, 43 percent of their teeth were given one point, and 36 percent were given zero mark. 14 percent were given three mark, and 5 percent were given three marks(p<.01). 4. As for plaque index for buccal posterior maxilla, 57 percent of their teeth were given one point, and 20 percent were given zero mark. 16 percent were given two mark, and 6.3 percent were given three marks(p<.01). 5. As for plaque index for lingual posterior mandibular, 56 percent of their teeth were given one point, and 27.8 percent were given zero mark. 9 percent were given three mark and 6 percent were given three mark(p<.001).

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.26-33
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• 2012

The purpose of this study was to find out the effect of dentifrice containing Horseradish (Armoracia rustica) root extracts on improvement of oral hygiene. The clinical evaluation was done participated by 80 adults volunteers who provided a informed consent for their participation. The participants were divided into two groups ; control group (using toothpaste without Horseradish extracts) and experimental group (using toothpaste containing Horseradish extracts). The checklist of the experiment includes the plaque index, gingival index and anti-caries activity. The anti-caries activity was measured by cultivating Streptococcus mutans for 48 hours then estimating the number of increased bacteria using Dentocult SM. The double-blind method was used in this study. The results of this study can be summarized as follows; 1. The plaque formation decreased 28% in control group, 58% in experimental group using dentifrice with Horseradish extracts compared to baseline data. 2. For gingival index, control group and experimental group showed 26% and 40% decrease compared to baseline data, respectively. 3. The score of caries activity test decreased by 4% for control group and 69% for experimental group compared to baseline data. According to the results, a dentifrice containing Horseradish extracts can improve oral hygiene.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.418-425
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• 2013

This study was investigated in order to provide basic data for prevention of periodontal disease and maintenance through proper lifestyle by finding the relevance of periodontal health with lifestyle habits. Data were collected from total of 326 subjects in their forties and fifties by using questionnaire and examination of periodontal health status. Results were analyzed by using IBM SPSS Statistics 19.0. The smoking status were statistically significant to gingival index (p<0.01), pocket depth (p<0.001), and clinical attachment loss (p<0.001). Smoking amount per day were statistically significant to gingival index (p<0.05), pocket depth (p<0.01), and clinical attachment loss (p<0.001). Duration of smoking were statistically significant to gingival index (p<0.05), pocket depth (p<0.01), and clinical attachment loss (p<0.001). Drinking cycle were statistically significant to gingival index (p<0.05), and clinical attachment loss (p<0.05). It is investigated that smoking (p<0.05) influence on clinical attachment loss. Dental care institute needs to make patients be aware of the fact that excessive smoking and drinking affect the periodontal health status for prevention of periodontal disease and maintenance of oral health. Therefore systematic educational programs to stop smoking and drinking should be prepared.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.371-378
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• 2014

This study aims to evaluate the influence of vitamin and mineral supplement intake, and degree of calcium and phosphorus intake on occurrence of dental caries in primary teeth. Research data was derived from the Fourth Korean National Health and Nutrition Examination Survey (KNHANES) and 1,139 Korean children of 3 to 6 years were selected as subject for this study. The dft index, nutrition factor including vitamin or mineral supplement intake and degree of intake for calcium (Ca) and phosphorus (P) were identified. Chi-square test was performed to assess the difference in socioeconomic status, oral health behavior and nutrition factor, including vitamin or mineral supplement intake and degree of intake for Ca and P. Linear regression analysis was performed to identify the relationship between the dft index and the related variables. As a result, the dft index was increased with the age. Significant differences in Ca intake was examined according to the sex, and P intake was different according to the sex in 3-year-old group. Among the 4-year-old children, the vitamin and mineral supplement takers had 1.206 less dft index than the non-takers. In conclusion, intake of Ca, P and vitamin/mineral supplement was not a pivotal factor to influence the incidence of primary teeth caries. However, significantly low dft index was observed from 4-year-old group who intake vitamin or mineral.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.832-838
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• 2004

This study investigated the effects of an antifat diet with $\beta$-cyclodextrin on the reduction of body weight, obesity index, body mass index, body fat mass, body circumferences and plasma lipid levels in obese Korean women. After maintaining an antifat diet for 45 days, there were significant reductions in body weight by 4 kg, obesity index by 5%, body mass index by 1 kg/$m^2$ and body fat mass by 7% as absolute values (p<0.05). When expressed as percentages of the decrease, these reductions remained significant at 4%, 13%, 4% and 20%, respectively (p<0.05). In addition, after maintaining this antifat diet for 45 days, there were also significant reductions in arm, waist, hip and thigh circumferences by 3 cm as absolute values when compared to before intake of antifat diet, and these reductions remained significant at 8%, 3.4%, 3% and 5%, respectively (p<0.05) as percentages of the decrease. Furthermore, this antifat diet significantly reduced triacylglyceride by 103 mg/dL, total cholesterol by 50 mg/dL and LDL-C by 50 mg/dL respectively (p<0.05). Thus, the present results demonstrate that $\beta$-cyclodextrin may have benefit as a novel food resource for diets to prevent obesity and control overweight in adult women.

• Journal of dental hygiene science
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• v.15 no.6
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• pp.712-720
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• 2015

The purpose of this study is to examine whether any correlation exists between the dental health capacity and preferred foods of Korean senior citizens over the age of 65 years. The 5th Korean National Health and Nutrition Survey were used. Tissue health index (T-health), Sound teeth (ST), Functioning teeth index (FS-T), Present teeth (PT), and Missing teeth (MT) were used as variables to assess the dental health capacity of the elderly. Preferred foods of the elderly included 63 foods that were categorized as cereals, pulses and roots, meat and poultry, fish, vegetables, sea algae, fruits, milk and dairy products, cream and sugar, and other foods. For data analysis, the weighted average was taken into consideration to generate planning files, and then complex sample analysis were conducted. For statistical analysis, frequency analysis, t-test, one-way ANOVA, and compound specimen linear regression analysis were conducted. T-health score was significantly high in the group with high preference for cereals, fruits, and other foods. In terms of age and economic status, 65~69 years, 70~74 years, and mid to low range in the income ranges scored high in T-health. ST score was significant in the group that preferred cereals, other foods; the corresponding demographic profiles represent 65~69 years, 70~74 years, and the mid-range income communities. FS-T was significant in relation with a preference for fruits, creams and sugars, other foods; the scores were also high for 65~69 years, 70~74 years, and mid-low to low income groups. PT and MT were significant in the group that preferred cereals and fruits; the same applied for 65~69 years, 70~74 years, and mid-low to low income individuals (p<0.05). Food preferences seemed to vary depending on the dental health state of the elderly, and the dental health state of the elderly may act as a risk factor for nutritional imbalance.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.2
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• pp.52-63
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• 2021

In previous research, the coastal wetlands were detected by using the vegetation indices or land cover classification maps derived from the multispectral bands of the satellite or aerial imagery, and this approach caused the various limitations for detecting the coastal wetlands with high accuracy due to the difficulty of acquiring both land cover and topographic information by using the single remote sensing data. This research suggested the efficient methodology for detecting the coastal wetlands using the sentinel-2 satellite image and SRTM(Shuttle Radar Topography Mission) DEM (Digital Elevation Model) acquired in Gomsoman Bay, west coasts of South Korea through the following steps. First, the NDWI(Normalized Difference Water Index) image was generated using the green and near-infrared bands of the given Sentinel-2 satellite image. Then, the binary image that separating lands and waters was generated from the NDWI image based on the pixel intensity value 0.2 as the threshold and the other binary image that separating the upper sea level areas and the under sea level areas was generated from the SRTM DEM based on the pixel intensity value 0 as the threshold. Finally, the coastal wetland map was generated by overlaying analysis of these binary images. The generated coastal wetland map had the 94% overall accuracy. In addition, the other types of wetlands such as inland wetlands or mountain wetlands were not detected in the generated coastal wetland map, which means that the generated coastal wetland map can be used for the coastal wetland management tasks.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.945-954
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• 2018

The purpose of this study is to analyze the life stress factors and the changing eating behaviors of the students. We selected a dental hygiene college in Seoul and Daejeon and surveyed 387 students with email and self-administered questionnaires. The studying(3.16) of the stress factors was the most contributing factor followed by career path 3.04, economic 2.97. Regarding differences in each life stress factors according to general characteristics, they were found statistically significant to Body mass index, economic condition, family conversation time and self recognition of health status. Results showed that 39.7% of students ate snacks 1 to 3 times per week, 44.0% preferred spicy flavors after stress, 47.7% ate more than usual after stress, also among the group with high stress was revealed bad results of eating behaviors. According to this study, we identified the factors that affect the daily stress of dental hygiene students and the consequent changes in eating behavior and the results will be consulted on the training and counseling to adjust to college life.