• Journal of dental hygiene science
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• v.8 no.4
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• pp.261-266
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• 2008

The purpose of this study was to examine the effects of the toothpick method, one of professional toothbrushing methods, on the prevention of periodontal diseases and the satisfaction level of patients with that. The subjects in this study were 33 patients who included 16 men and 17 women. After the toothpick method was applied to the selected patients from January 9 to February 28, 2008, the collected data were analyzed with SPSS (Statistical Package for the Social Science) 12.0 program. The findings of the study were as follows: First, the patients investigated showed a 0.71 reduction in PI than in the past. The index of bleeding upon probing stood at 5.12, which dropped from 8.09 in the beginning. Second, the patients gave a mean of 4.20 to the professional toothbrushing out of possible five points, which showed that they expressed satisfaction with that. Third, as for the relationship between general characteristics and satisfaction level, the women were more satisfied with that ($4.25{\pm}0.33$). By age group, those who were in their 60s and up found that more satisfactory ($4.31{\pm}0.30$). Fourth, as to changes in oral symptoms by gender, the largest number of the men and women considered their gums to become healthier after the professional toothbrushing was applied. The above-mentioned findings suggested that dental institutions should be equipped with well-educated oral health care personnels who are responsible for the periodontal health of patients, and the development of oral health promotion programs is urgently required as well.

• The Korean Journal of Applied Statistics
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• v.24 no.5
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• pp.931-939
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• 2011

In practice, thresholds are determined by the two subjective assessment methods in a generalized pareto distribution of mean extreme function(MEF-graph) or Hill-graph. To remedy the problem of subjectiveness of these methods, we propose an alternative method to determine the threshold based on the robust statistics. We compared the MEF-graph, Hill-graph and our method through VaRs on the Korean stock market data from January 5, 1987 to August 3, 2009. As a result, the VaR based on the proposed method is not much different from the existing methods, and the standard deviation of VaR for our method was the smallest. The results show that our method can be a promising alternative to determine thresholds of the generalized pareto distributions.

• Communications for Statistical Applications and Methods
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• v.16 no.3
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• pp.449-461
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• 2009

Higher sigma quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The process capability indices and the sigma level $Z_{st}$ ave been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on statistical estimation under normal process which may result in unreliable assessments of process performance. In this paper, we consider statistical estimation for bivariate VPCI(Vector-valued Process Capability Index) $C_{pkl}=(C_{pklx},\;C_{pklx})$ under Marshall and Olkin (1967)'s bivariate exponential process. First, we derive some limiting distribution for statistical inference of bivariate VPCI $C_{pkl}$. And we propose two asymptotic normal confidence regions for bivariate VPCI $C_{pkl}$. The proposed method may be very useful under bivariate exponential process. A numerical result based on our proposed method shows to be more reliable.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.33-40
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• 2015

In the correlation formulas related to consolidation proposed at present, the analyzed areas are limited to certain overseas or domestic areas and in order to increase the number of data, experimental data of different areas are integrated and therefore in many cases application is difficult. In addition, models have been developed without clear statistic evaluation of the obtained data. Accordingly, this study divided the soft areas of the west coast into Hangang, Kumgang and Yeongsangang in order to maximally reduce uncertainty of the experimental data and performed normality test and regression analysis on the physical and dynamic characteristics. According to the analysis result, the compression index and the modified compression index had strong linearity and in all areas modified compression index and initial void ratio had closest correlation, followed by total unit weight, water contents and liquid limits. As for overconsolidation ratio with depth, the width of overconsolidation ratio was large when the depth was less than 5 to 6 m in all areas and when the depth was over 5 to 6 m, the ratio was constant.

• Journal of Korean society of Dental Hygiene
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• v.15 no.3
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• pp.451-459
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• 2015

Objectives: The objective of this study is to investigate oral health behavior, PHP index and OHIP, awareness, attitude and behavior toward oral health in the foreign factory workers. Thsi study will provide the basic data for the improvement of the foreigners' quality of life. Methods: A self-reported questionnaire was completed by 126 Sri Lankans and 76 Chinese over 20 years old in Daegu and Gyeongbuk from January to April, 2012 through man to man interview after receiving informed consent. The questionnaire included oral health status, PHP index and OHIP. Results: OHIP was closely related to sex, marital status, and medical expense burden. PHP index was closely related to religion and income. The averages of OHP and PHP were 4.36 and 3.7, respectively and very bad. OHIP was influenced by number of toothbrushing, time of toothbrushing, use of oral hygiene device, and dental visit within a year. PHP index was influenced by the area of toothbrushing, time of toothbrushing, and the dental visit within a year. Regression analysis of PHP index according to OHIP and oral care conditions showed the equation. Y(OHIP)=2.999+0.103(area of toothbrushing)+0.346(the use of oral hygiene article)+ 0.077(visiting to the dentist during the past one year)-0.173(PHP index)(p<0.05). Conclusions: Low PHP index in the foreign workers affected quality of life. So the company must provide the continuing oral health care for the foreign workers every year. The concern for the health care for the foreigners will improve oral health behavior in the future.

• Journal of Korean society of Dental Hygiene
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• v.17 no.2
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• pp.215-224
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• 2017

Objectives: The objective of the study was to investigate the oral health index in orthodontic patients by dividing the patients into two groups; the OHCP (Oral Health Care Program)group and the control group. Methods: The subjects in Busan were divided into two groups, including the OHCP group (205 patients) and the control group (119 patients), during orthodontic treatment that took place from October 2015 to October 2016. The oral health index was subdivided into three groups according to the oral interest level of the OHCP and control groups. The oral health index used was Simplified Oral Hygiene Index (S-OHI) and Community Periodontal Index of Treatment Needs (CPITN). Results: When the degree of oral interest was compared, he OHCP group before application and after application saw a significant difference (p<0.001) in all the variables except the S-DI. Meanwhile, the control group saw no significant difference in most variables. after OHCP application, The OHCP group was significant differences in all variables (p<0.001), and the control group was no significant difference in most variables. Conclusions: Oral hygiene management for orthodontic patients should be systematically and professionally programmed differently from that for general dental treatment patients. As such, dental hygienists should take this into consideration and proactively develop and research programs similar to OHCP for orthodontic patients.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1229-1237
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• 2013

In this study, the theory of spherical indentation based on incremental plasticity is extended to an indentation method for evaluating creep properties. Through finite element analysis (FEA), the point where the elastic strain effect is negligible and the creep strain gradient constant is taken as the optimum point for obtaining the equivalent strain rate and stress. Based on FE results for spherical indentation with various values of creep exponent and creep coefficient, we derive by regression an equation to calculate creep properties using two normalized variables. Finally a program is generated to calculate creep exponent and creep coefficient. With this method, we obtain from the load-depth curve creep exponents with an average error of less than 1.5 % and creep coefficients with an average error of less than 1.0 %.

• Journal of dental hygiene science
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• v.12 no.2
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• pp.163-170
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• 2012

The purpose of this study was determine the effects of professional tooth cleaning and plaque control instruction(PT & PCI) on reduction of peri-implantitis. A total 80 implant patients were investigated using O'Leary plague index(PI), L${\ddot{o}}$e & Silness gingival index(GI), implant bone loss(BL). While the PT & PCI was conducted by using 'Watanabe method' after scaling for the experimental group, the engine polishing and a plaque control instruction was operated by rolling method after scaling for the control group. The collected data were analyzed with t-test, ANOVA, paired t-test and stepwise multiple regression. PI and GI of the experimental group significantly decreased than the control group(p<0.05). BL, also tended to decreased in the experimental group than the control group(p=0.155). Multiple regression analysis, the factors that was highly correlated with PT & PCI on the PI and GI. According to the implant characteristics, implant location and duration were closely related to PI(p<0.05). Therefore, the PT & PCI is one of the effective methods to reduce the failure caused by the peri-implantitis. Based on this conclusion, that it would be meaningful if the proposed PT & PCI is applied to the oral health management programs of the implant patients.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.643-652
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• 2002

Data were consisted of the ten body measurements (withers height, rump height, body length, chest depth, chest width, rump width, rump length, thurls width, hipbone width and chest girth) of 642 steers (Korean cattle), which was entered in the National Beef Quality Contest hosted by the Korea Animal Improvement Association from 1997 to 2001. A principal components analysis was used to classify the body types of the steers, and estimate the correlations between carcass traits and principal components for the body measurements of the first, second, third and fourth period, respectively. The first principal component of body measurements at the first, second, third and fourth period accounted for 76.0%, 83.0%, 72.7% and 57.4% of the total variance, respectively. The sum of first, second and third principal component at each period accounted for 86.69%, 90.49%, 84.62% and 77.26% of the total variance, respectively. At each period, all the first principal component of the body measurements were positive and it generally showed large framed body shape. The size of body was influenced mostly by chest depth(0.328${\sim}$0.339) and rump length(0.325${\sim}$0.341). The second, third and fourth principal component at the each period were various. There were positive correlations between principal components index of each period and carcass traits such as carcass weight(0.539${\sim}$0.755), average daily gain(0.256${\sim}$0.564), backfat thickness(0.227${\sim}$0.280), and eye muscle area(0.187${\sim}$0.344). The correlation with yield grade index(－0.246${\sim}$－0.110), however, was negative. The correlation with marbling score(0.066${\sim}$0.099) was low or statistically insignificant. According to principal component indexes of the second, third, and fourth components, the correlations with the carcass traits were various. There were no large differences between the correlations of the single body measurement trait with the carcass traits and the correlations of the first principal component indexes with the carcass traits.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.2
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• pp.105-113
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• 2001

This study was conducted to reveal the effects of local climatic conditions on the vegetative growth in a mature stand of Korean white pine based on climatic estimates. For this, the annual increments of stand variables such as DBH, height, basal area and volume were measured and estimated for seven years from 1974 to 1980. The local climatic conditions in the study site were also estimated by both a topoclimatological method and a spatial statistical technique. The local climatic conditions were then correlated with and regressed on the growth factors to reveal the relationships between the climatic estimates and the growth. It is found that relatively high temperatures had positive effects on the diameter growth. The yearly diameter growth increased when each of mean, maximum, and minimum temperature during the growing season was high. Height growth showed positively significant correlation with three climatic variables. The most important variable influencing height growth was the average of maximum temperature for 10 months from January to October. It means that the higher the average of maximum temperature for 10 months from January to October is, the more height growth of Korean white pine increases. Other climatic variables related to height growth were average of minimum temperature for 3 months in the early growing season and mean relative humidity for the growing season. Six climatic variables related to temperature had effects on basal area increment and all of them were positively correlated with basal area increment. Especially, temperatures from January to March were important factors affecting the basal area increment. In volume increment, high correlation was also recognized with most of temperature variables. This tendency was the same as the results in diameter and hight increments. This means that the volume growth increases when temperatures during the growing season are relatively high.