• Steel and Composite Structures
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• v.41 no.6
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• pp.899-910
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• 2021

A 4-unknown shear deformation theory is applied to investigate the vibration of functionally graded plates under thermal environment. The plate is fabricated from a functionally graded material mixed of ceramic and metal with continuously varying material properties through the plate thickness. Three types of thermal loadings, uniform, linear and nonlinear temperature rises along the plate thickness are taken into account. The present theory contains four unknown functions as against five or more in other higher order shear deformation theories. The through-the-thickness distributions of transverse shear stresses of the plate are considered to vary parabolically and vanish at upper and lower surfaces. The present model does not require any problem dependent shear correction factor. Analytical solutions for the free vibration analysis are derived based on Fourier series that satisfy the boundary conditions (Navier's method). Benchmark solutions are firstly considered to evaluate the accuracy of the proposed model. Comparisons with the solutions available in literature revealed the good capabilities of the present model for the simulations of vibration responses of FG plates. Some parametric studies are carried out for the frequency analysis by varying the volume fraction profile and the temperature distribution across the plate thickness.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.307-321
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• 2017

This study examined the developmental changes of adolescent personality regarding personality traits of Big 5 model in 2,260 middle and high school students. We found that there was a difference in the developmental change of personality 5 factor according to sex and grade. In addition, we investigated the timing and characteristics of adolescent problem behavior by analyzing the sub - factors of neurosis. Analysis was used for One-Way ANOVA. if there is significant differences we proceeded post hoc tests. The results of this study are as follows; first, The five personality traits of the adolescents showed differences according to gender. The girls were higher than boys in the Openness, Conscientiousness and Extraversion. In contrast, the boys were higher than girls in the Neuroticism. Second, There was a difference in the characteristics of five personality traits of adolescents according to grade. Third, Gender-specific developmental grade tendency characteristics of adolescent personality trait shows a different pattern in gender. Especially, in the analysis by gender and grade boys showed that personality traits prominent in the middle school Grade 2. likewise, girls showed that personality traits prominent in the high school Grade 3. Then, associated with Neuroticism the Externalizing behavior problems was found to be expressed in the middle school Grade 1 and 2. likewise, the Internalizing behavior problems was found to be expressed in high school Grade 3. Therefore, this study was able to determine the current developmental change in personality traits adolescence of our country. Also it found that mental health problems can be a different expression depending on gender and grade.

• Culinary science and hospitality research
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• v.16 no.5
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• pp.149-163
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• 2010

This study planned study model through documentary research and drew hypothesis to analyze how teamwork of servant leadership has an influence on job satisfaction aiming at full time employee under department head and contract worker of five star hotel in Busan. As a survey term, from April 5th, 2010 to April 23th, 2010, it distributed total 300 questionnaires, 60 questionnaires for each hotel, and then 242 questionnaires were used for empirical analysis. It analyzed data using SPSS WIN Version 12.0 statistics package program, and verified through frequency analysis, reliability analysis, factor analysis, regression analysis. As a result of verification for influence of servant leadership on interchange which is one of teamwork, it showed that community formation factor has a positive influence on interchange, and as a result of verification for influence on communication which is one of teamwork, I could find out that higher the level of bond of sympathy formation and community formation factor are, higher the communication becomes. As a result of verification for influence on interdependence which is one of teamwork, it showed that community formation, stewardship, vision, commitment to growth factor have a positive influence on interdependence. As a result of verification for influence of teamwork factor on job satisfaction, it showed that all factors have a positive influence. As a result of this study. I could find out that member' positive perception on leader in hotel organization can be a basis deriving job satisfaction though teamwork.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.1
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• pp.17-32
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• 2021

Objectives The present study was designed to find out the therapeutic effects and possible underlying mechanism of Buja-tang, a herbal complex formula on experimental monosodium iodoacetate (MIA)-induced osteoarthritis. Methods Osteoarthritis models were created via intra-joint injection of MIA (50 μL with 80 mg/mL) in rats. Rats were divided into five groups and each group consisted of seven. Normal group was not injected MIA and did a normal diet. Control group injected MIA and received distilled water. Indo injected MIA and oral administration of 5 mg/kg of indomethacin. BJTL injected MIA and oral administration of 100 mg/kg of Buja-tang. BJTH injected MIA and oral administration of 200 mg/kg of Buja-tang. We analyzed weight-bearing ability of hind paws, oxidative stress related factor, antioxidant protein, inflammatory protein, inflammatory messenger and cytokine in joint tissue. Pathological observation of knee cartilage tissue structures was also performed with hematoxylin & eosin and safranin-O chromosomes. Results Weight-bearing ability of hind paws showed a tendency to reduce pain. The incidence of nicotinamide adenine dinucleotide phosphate oxidase and p22phox in articular tissue was significantly reduced, and the incidence of nuclear factor-erythroid 2-related factor 2 and heme oxygenase-1 and superoxide dismutases was significantly increased. The incidence of phosphorylated inhibitor of κBα, nuclear factor-kappa B p65, inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor alpha, interleukin (IL)-6, and IL-1β decreased significantly. In pathological observation, cartilage tissue damaged by MIAs in biopsy has significantly recovered from Buja-tang administration. Conclusions Buja-tang has anti-inflammation, antioxidation and pain relief effects. So this is thought to inhibit the progress of osteoarthritis in rat caused by the MIA.

• Korean Journal of Agricultural Science
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• v.31 no.2
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• pp.135-148
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• 2004

Rice is not only main food but also key farm income source of Korean farmers. In spite of the above facts, rice productivity was decreased on account of drought in every 2 or 3 years interval owing to the vulnerability of irrigation facilities throughout Korea in the past decades. As an context of the first five year economic development plan, all weather farming programme including 4 big river basin comprehensive development projects and large and medium sized irrigation water development projects were carried out successfully. Therefore the area of irrigated paddy were increased from 58% in 1970 to 76.2% in 1999. In the past decades, the Government had invested heavy financial funds to develop irrigation water but as an factor share analysis, the contribution rates of irrigation water and investment for farmland base development project have not been identified yet in national agricultural economic level. It is very scarce to find out the papers concerned to macro-economic factor share analysis or contribution rates of water and investment cost to rice production value in Korea considering the production function of the quantity of irrigation water and investment cost as independent variables. Accordingly this paper covered and aimed at identifying (1) derivation of rice production function with the time serial data from 1965 to 1999 and the contribution rates of irrigation water and total investment cost for farmland base development project. The analytical model of the contribution rates was adapted the famous Cobb-Douglass production function. According to the model analysis, the contribution rate of irrigation water to rice production in Korea was shown 37.8% which was equivalent to 0.28 of the production elasticity of water. The contribution rate of farmland base development project cost was revealed 22% and direct production cost of rice was contributed 60% in the growth of rice production and farm mechanization costs contributed to 18% of it respectively. The two contribution rates comparing with the direct production cost were small but without irrigation water and farmland base development, application of high-pay off inputs and farm mechanization might be impossible. Considering the food security and to cope with the frequent drought, rice farming and investment for the irrigation water development should be continued even in WTO system.

• Journal of Preventive Medicine and Public Health
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• v.38 no.2
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• pp.208-214
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• 2005

Objectives: This study was performed to examine the factors affecting re-smoking in male workers. Methods: A self-administrated questionnaire survey was conducted during April 2003 to examine the smoking state of 1,154 employees of a company that launched a smoking cessation campaign in1998. Five hundred and eighty seven persons, who had stopped smoking for at least one week, were selected as the final study subjects. This study collected data on smoking cessation success or failure for 6 months, and looked at the factors having an effect on re-smoking within this period. This study employed the Health Belief Model as its theoretical basis. Results: The re-smoking rate of the 587 study subjects who had stopped smoking for at least one week was 44.8% within the 6 month period. In a simple analysis, the re-smoking rates were higher in workers with a low age, on day and night shifts, blue collar, of a low rank, where this was their second attempt at smoking cessation and for those with a shorter job duration (p<0.05). Of the cues to action variables in the Heath Belief Model, re-smoking was significantly related with the perceived susceptibility factor, economic advantages of smoking cessation among the perceived benefits factor, the degree of cessation trial's barrier of the perceived barriers factor, smoking symptom experience, recognition of the degree of harmfulness of environmental tobacco smoke and the existence of chronic disease due to smoking (p<0.05). In the multiple logistic regression analysis for re-smoking, the significant variables were age, perceived susceptibility for disease, economic advantages due to smoking cessation, the perceived barrier for smoking cessation, recognition on the degree of harmfulness of environmental tobacco smoke, the existence of chronic disease due to smoking and the number of attempts at smoking cessation (p<0.05). Conclusion: From the result of this study, for an effective smoking ban policy within the work place, health education that improves the knowledge of the adverse health effects of smoking and the harmfulness of environmental tobacco smoke will be required, as well as counter plans to reduce the barriers for smoking cessation.

• Journal of Korean Society of Steel Construction
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• v.22 no.4
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• pp.325-334
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• 2010

In this study, an unbraced five-story steel-framed structure was designed in accordance with KBC2005 to understand the features of structural behavior for the arrangement of semi-rigid connections. A pushover analysis of the structural models was performed, wherein all the connections were idealized as fully rigid and semi-rigid. Additionally, horizontal and vertical arrangements of the semi-rigid connection were adopted for the models. A fiber model was utilized for the moment-curvature relationship of the steel beam and the column, and a three-parameter power model was adopted for the moment-rotation angle of the semi-rigid connection. The top displacement, base-shear force, required ductility for the connection, sequence of the plastic hinge, and design factors such as the overstrength factor, ductility factor, and response modification coefficient were investigated using the pushover analysis of a 2D structure subjected to the equivalent static lateral force of KBC2005. The partial arrangement of the semi-rigid connection was found to have secured higher strength and lateral stiffness than that of the A-Semi frame, and greater ductility than the A-Rigid frame. The TSD connection was found suitable for use for economy and safety in the sample structure.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1369-1384
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• 2013

In this study, we investigate various factors affecting five kinds of life planners' satisfaction after turnover which are general, human relations within organization, sales environment support, economic, life planner management system. Also we suggest theoretical and practical implication to them. The results of survey of life planners are as follows. First, in the general life planners' satisfaction after turnover, insurance company belonged to, recognition on own sales ability, life planners' satisfaction level, financial and insurance related award, education level, marital status, size of branch, and surrounding recognition about life planner are influential factors on it. Second, factors which affect the life planners' human relations satisfaction within organization after turnover are size of branch, surrounding recognition about life planner, and insurance company belonged to. Third, factors which affect the life planners' sales environment support satisfaction after turnover are surrounding recognition on life planner, insurance company belonged to, certificates relating to finance or insurance, size of branch, Fourth, in the solicitors' economic satisfaction after turnover, mainly demographic factors such as education level, marital status, age are crucial to it and also life planners' satisfaction level is influential factor. Last, in the solicitors' management system satisfaction, only experienced turnover type is a influential factor.

• Journal of Distribution Science
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• v.13 no.3
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• pp.79-91
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• 2015

Purpose - First, the study identifies and analyzes consumer preferences with regard to health foods and supplements. Second, it identifies and analyzes consumer preferences with regard to the properties of Vitamin C supplements. Third, in order to provide a basic data for the development of Vitamin C supplements and to measure how consumers value the properties of different Vitamin C products, a consumer survey was conducted through the choice-based conjoint model. Based on the results, the research estimates consumers' relative product-related priorities as well as price levels and willingness to pay (WTP) for different product types, and makes suggestions regarding consumer-oriented new product development and progressive directions for the successful launch of health foods and supplements. Research design, data, and methodology - This study aims to define the attributes of health foods and supplements based on several characteristics including their natural ingredients, product price, product originality, natural ingredient content, and additional functional ingredients, and makes suggestions regarding strategic market pricing and product development for health foods and supplements according to customer attitudes and characteristics. The research used choice-based conjoint analysis methodology based on the Multinomial Logic Model and collected 94 questionnaires filled out by users of Korean Vitamin C supplements. Results - Product price is the most influential factor among the five analyzed properties. When consumers buy Vitamin C products, the relative significance level of four of the examined properties is as follows: 40.9% for product price, 23.3% for product originality, 21.9% for natural ingredient content, and 13.9% for additional functional ingredients. Vitamin C content is excluded as it is not a statistically significant factor. It is interesting that supplement manufacturers and retailers consider Vitamin C content to be very important whereas consumers do not regard it as an important factor at the time of purchase. The results for the marginal willingness to pay (MWTP) for each property of Vitamin C supplements show that consumers are willing to pay an additional 11,146 Korean won for a 50% increase in the natural ingredient content. With regard to product originality, consumers are willing to pay an additional 11,301 Korean won for products manufactured in Europe than for products manufactured in China. Moreover, consumers show a greater preference for products manufactured in Korea than in Europe. However, consumers are not willing to pay more for additional Vitamin C or additional functional ingredients added to Vitamin C products. Conclusions - According to the results of consumer research on Vitamin C supplements, which represent a popular health food supplement in Korea, most Korean health food and supplement companies are not consumer- or market-oriented when developing new products. Companies gather information from either R&D specialists or sales managers and their opinions are highly reflected in new product development. The study's results will help companies recognize the importance of understanding consumers' unmet needs in advance to develop new products in the future.

• The Journal of Internal Korean Medicine
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• v.44 no.3
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• pp.402-417
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• 2023

Objective: Liver fibrosis is a highly conserved wound-healing response and the final common pathway of chronic inflammatory injury. This study aimed to evaluate the potential anti-fibrotic effect of the combination of Rhei Radix et Rhizoma water extract (RW) and silymarin in a thioacetamide (TAA)-induced liver fibrosis model. Methods: The liver fibrosis mouse model was established through the intraperitoneal injection of TAA (1 week 100 mg/kg, 2-3 weeks 200 mg/kg, 4-8 weeks 400 mg/kg) three times per week for eight weeks. Animal experiments were conducted in five groups; Normal, Control (TAA-induced liver fibrosis mice), Sily (silymarin 50 mg/kg), RSL (RW 50 mg/kg+silymarin 50 mg/kg), and RSH (RW 100 mg/kg+silymarin 50 mg/kg). Biochemical analyses were measured in serum, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA), and ammonia levels. Liver inflammatory cytokines and fibrous biomarkers were measured by Western blot analysis, and liver histopathology was evaluated through tissue staining. Results: A significant decrease in the liver function markers AST and ALT and a reduction in ammonia and total bilirubin were observed in the group treated with RSL and RSH. Measurement of reactive oxygen species and MDA revealed a significant decrease in the RSL and RSH administration group compared to the TAA induction group. The expression of extracellular matrix-related proteins, such as transforming growth factor β1, α-smooth muscle actin, and collagen type I alpha 1, was likewise significantly decreased. All drug-administered groups had increased matrix metalloproteinase-9 but a decreasing tissue inhibitor of matrix metalloproteinase-1. RSL and RSH exerted a significant upregulation of NADPH oxidase 2, p22^phox, and p47^phox, which are oxidative stress-related factors. Furthermore, pro-inflammatory proteins such as cyclooxygenase 2 and interleukin-1β were markedly suppressed through the inhibition of nuclear factor kappa B activation. Conclusions: The administration of RW and silymarin suppressed the NADPH oxidase factor protein level and showed a tendency to reduce inflammation-related enzymes. These results suggest that the combined administration of RW and silymarin improves acute liver injury induced by TAA.