• Journal of the Korean GEO-environmental Society
• /
• 제17권10호
• /
• pp.33-43
• /
• 2016

The determination of in-situ capping materials is one of the most important factors to design in-situ capping in order to protect capping materials from erosion. Previous studies have established relationship between the velocity induced by wave energy and effective diameter of sediments, but they are mostly empirical and numerical researches which is too complicated for field engineers to analyze the erosion of in-situ capping materials. This study provides simple analytical solutions and reliability based on hydraulic model test results. Experimental results show that measured flow velocities with respect to depth induced by wave energy are almost the same as estimated velocities and the erosion resistances of the different effective particle diameters can be estimated.

• Journal of the Korea Fashion and Costume Design Association
• /
• 제14권3호
• /
• pp.111-122
• /
• 2012

This study analyzed the differences in value perception and purchasing intention for natural cosmetics by LOHAS class and investigated what influences people's value perception for natural cosmetics had on their purchasing intention. Total 450 questionnaires were distributed to adults of over 20s to 50s for the period from Dec. 1, 2011 to Dec. 14 and 410 questionnaires were used as analysis data. As for collected data, the statistical package SPSS 18.0 Version was used for factor analysis, frequency analysis, reliability test, one-way ANOVA, Chi-Square test, Scheffe-test, correlations analysis and multiple regression analysis. LOHAS class was divided into three groups (higher, middle and lower) based on LOHAS index. Through factor analysis, the value perception for natural cosmetics were divided into three factors (social value, emotional and functional value perception). The results of this study were obtained as below. First, in case of the value perception for natural cosmetics by LOHAS class, it was demonstrated that the higher LOHAS classes they were, the higher value perception for natural cosmetics (social, emotional and functional value perception) they had. Second, in case of the effects of the value perception for natural cosmetics by LOHAS class on their purchasing intention (intention to use and recommendation of usage), it was found that their value perception influenced their purchasing intention. Social value perception and functional value perception, especially social value perception largely affected the purchasing intention of all LOHAS classes, while emotional value perception didn't affected the purchasing intention.

• Journal of Dental Anesthesia and Pain Medicine
• /
• 제19권6호
• /
• pp.361-367
• /
• 2019

Background: Although studies on dental fear in relation to sex and age have been conducted, there have been few nationwide studies particularly on the youth sector. In addition, no validity and reliability verifications have been implemented for new research groups on the Korean version of the Dental Fear Survey (K-DFS). Therefore, this study aimed to apply the K-DFS developed in a previous study on Korean youth to draw conclusions on dental fear among the youth. Methods: This study used the K-DFS, a Korean translation of Kleinknecht's Dental Fear Survey for elementary school, middle school, and high school students. This study selected 2,161 young people of various ages as participants and increased the validity of the research results by expanding nationwide the scope of the study area. Results: Differences in fear levels according to sex were higher in boys fear behavior scores than in girls' regarding dental treatment (P < 0.05). Students with dental fear had higher scores on items associated with dental treatment and fear of dental stimuli compared with students without dental fear (P < 0.05). Differences were observed among the three groups (P < 0.05). However, the results of logistic regression analysis showed no statistically significant differences for dental visits based on sex, grade, and other subcomponents (P > 0.05). Conclusion: By verifying the validity of the newly developed K-DFS, this research confirmed its utility as a dental fear questionnaire. Therefore, there can be no objection that the grounds for criticism have been established according to conventional wisdom. In the future, however, developing and studying the limits of K-DFS that overcome the factors of dental fear, especially pain, will help reduce dental fear in adolescents.

• Journal of Environmental Health Sciences
• /
• 제43권4호
• /
• pp.298-306
• /
• 2017

Objectives: Since 1998, the Korea National Health and Nutrition Examination Survey (KNHANES) has been conducted in order to investigate the health and nutritional status of Koreans. The food intake data of individuals in the KNHANES has also been utilized as source dataset for risk assessment of chemicals via food. To improve the reliability of intake estimation and prevent missing data for less-responded foods, the structure of integrated long-standing datasets is significant. However, it is difficult to merge multi-year survey datasets due to ineffective cleaning processes for handling extensive numbers of codes for each food item along with changes in dietary habits over time. Therefore, this study aims at 1) cleaning the process of abnormal data 2) generation of integrated long-standing raw data, and 3) contributing to the production of consistent dietary exposure factors. Methods: Codebooks, the guideline book, and raw intake data from KNHANES V and VI were used for analysis. The violation of the primary key constraint and the $1^{st}-3rd$ normal form in relational database theory were tested for the codebook and the structure of the raw data, respectively. Afterwards, the cleaning process was executed for the raw data by using these integrated codes. Results: Duplication of key records and abnormality in table structures were observed. However, after adjusting according to the suggested method above, the codes were corrected and integrated codes were newly created. Finally, we were able to clean the raw data provided by respondents to the KNHANES survey. Conclusion: The results of this study will contribute to the integration of the multi-year datasets and help improve the data production system by clarifying, testing, and verifying the primary key, integrity of the code, and primitive data structure according to the database normalization theory in the national health data.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제11권4호
• /
• pp.55-66
• /
• 1991

Presented is a study on the realistic determination of design loads and design criteria for bridge structures. The current bridge design code does not consider realistically the uncertainties inherent in loads and resistances and thus the level of safety varies greatly among the bridge spans. The resonable bridge design loads and design criteria which exhibit uniform reliability among various bridge spans are therefore derived in the present paper. The proposed design loads are determined from the analysis of numerous data obtained from actual traffic survey and the design criteria are based on the advanced concept of load and resistance factor format. The live load factors take into account resonably the effects of traffic volume increase. The proposed design loads and design criteria show uniform safety level for various bridge spans and reasonably consider the effects of traffic volume increase. The present study provides useful and valuable data for new version of our bridge design code.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제4권1호
• /
• pp.59-68
• /
• 1984

Theoretical equations are derived to estimate the larteral earth pressures acting on piles with various shape of pile section due to lateral soil movements. And also examination of characteristics of the equations and comparison with other equations are carried out. The equations can be derived by calculating the difference between the two earth pressures acting on front and back sides of pile's row under plastic state satisfying Mohr-Coulomb's yield criterion, which is developed on tile soil between two piles among the piles in a row. The theoretical equations can reasonably consider the pile section-shape, the pile interval and the plastic condition in the soils just around piles. Additionally, the factors about soils and piles influencing on the lateral earth pressures are clarified and the high reliability of the equations is proved.

• Journal of the Korean Society of Clothing and Textiles
• /
• 제36권2호
• /
• pp.152-164
• /
• 2012

This study develops a valid and reliable scale to evaluate customer orientation for clothing salespeople in order to provide a foundation for systematic and empirical research in the apparel industry. The study was conducted in two phases. First, a scale was developed to evaluate the customer orientation of clothing salespeople through a qualitative method. The second phase involved the verification of the validity of the developed evaluation questions through a quantitative method. The subjects of this study were 327 clothing salespeople, and the results were analyzed using AMOS 7.0 and SPSS 15.0. The results were as follows: First, customer orientation questions were elicited from in-depth interviews with fashion sales-people, analyses of fashion magazine articles, and previous studies. From the results, 38 preliminary questions were selected based on categorization, modification, and expert analyses of the content validity. Second, in order to verify the validity of the customer orientation scale that consisted of 24 questions in 7 factors, we performed a verification of the convergent validity through an assessment of the magnitude of standardization factor loading, average variance extracted (AVE), and construct reliability. Discriminant validity was verified using the AVE of each of the two constructs and a comparison of the square of the correlation between the constructs. According to the results, the measured values were above or near the guideline values that demonstrates the validity of the customer orientation scale.

• Journal of Korean Society of societal Security
• /
• 제1권2호
• /
• pp.61-66
• /
• 2008

More than 70% of Korea consists of mountainous area and during the construction of roads and railroads many cut-slopes are inevitably formed. A number of environmental factors, such as the rainy season and frost heave during winter/thaw during spring, can result in rock falls and landslides. The failure of slopes is increasing every year and can cause damage to vehicles, personal injury and even fatality. In order to help protect people and property, there is a need for real-time monitoring systems to detect the early stages of slope failures. In this respect, the GMG has been using Translation Rotation Settlement (TRS) sensor units installed on slopes to monitor movement in real-time. However, the data lines of this system are vulnerable and the whole system can be damaged by a single lightning strike. In order to overcome this, GMG have proposed the use of Ubiquitous Sensor Networks (USN). The adoption of a USN system in lieu of data cables can help to minimize the risk of lightning damage and improve the reliability of slope monitoring systems.

• Korean journal of food and cookery science
• /
• 제30권1호
• /
• pp.84-91
• /
• 2014

The purpose of this study was to identify the effects of emotional labor on emotional exhaustion among school dietitians according to the level of their self-efficacy. A survey was administered on 300 school dietitians during September 2012 and a total of 277 usable questionnaires were received. The data were analyzed by using the SPSS 18.0 package program. As a result of principal factor analysis for validity test, 26 variables were classified into one factor for self-efficacy, three factors for emotional labor and one factor for emotional exhaustion with a total variance percentage of 67.371%. Internal consistency was estimated by Cronbach's alpha, which yielded reliability coefficients of 0.922 (self-efficacy), 0.916 (emotional display), 0.806 (surface acting), 0.808 (deep acting) and 0.850 (emotional exhaustion). Subjects were segmented into 2 groups of 'high self-efficacy' (n = 159) and 'low self-efficacy' (n = 118) according to the cluster analysis for self-efficacy variables. The 'high self-efficacy' group exhibited higher education(p < 0.01) and served less lunch meals than other groups (p < 0.05). According to multiple regression analysis, the emotional display proved to be significantly and positively related to emotional exhaustion (${\beta}$=0.319, p<0.001) in high self-efficacy group. However both emotional display (${\beta}$=0.233, p<0.05) and surface acting (${\beta}$=0.262, p<0.01) were positively related to emotional exhaustion in the low self-efficacy group. These results suggest that school dietitians should be more aware of their self-efficacy to relieve the effects of the emotional labor on emotional exhaustion.

• Journal of Veterinary Clinics
• /
• 제28권4호
• /
• pp.422-426
• /
• 2011

For a national survey in which wide geographic region or an entire country is targeted, multi-stage sampling approach is widely used to overcome the problem of simple random sampling, to consider both herd- and animallevel factors associated with disease occurrence, and to adjust clustering effect of disease in the population in the calculation of sample size. The aim of this study was to establish sample size for estimating bovine tuberculosis (TB) in Korea using stratified two-stage sampling design. The sample size was determined by taking into account the possible clustering of TB-infected animals on individual herds to increase the reliability of survey results. In this study, the country was stratified into nine provinces (administrative unit) and herd, the primary sampling unit, was considered as a cluster. For all analyses, design effect of 2, between-cluster prevalence of 50% to yield maximum sample size, and mean herd size of 65 were assumed due to lack of information available. Using a two-stage sampling scheme, the number of cattle sampled per herd was 65 cattle, regardless of confidence level, prevalence, and mean herd size examined. Number of clusters to be sampled at a 95% level of confidence was estimated to be 296, 74, 33, 19, 12, and 9 for desired precision of 0.01, 0.02, 0.03, 0.04, 0.05, and 0.06, respectively. Therefore, the total sample size with a 95% confidence level was 172,872, 43,218, 19,224, 10,818, 6,930, and 4,806 for desired precision ranging from 0.01 to 0.06. The sample size was increased with desired precision and design effect. In a situation where the number of cattle sampled per herd is fixed ranging from 5 to 40 with a 5-head interval, total sample size with a 95% confidence level was estimated to be 6,480, 10,080, 13,770, 17,280, 20.925, 24,570, 28,350, and 31,680, respectively. The percent increase in total sample size resulting from the use of intra-cluster correlation coefficient of 0.3 was 22.2, 32.1, 36.3, 39.6, 41.9, 42.9, 42,2, and 44.3%, respectively in comparison to the use of coefficient of 0.2.