• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.2
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• pp.111-117
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• 2001

There are three designs of thread form in screw type implants: V-thread, Reverse buttress thread and Square thread. The purpose of this study was to find out how thread form designs have an influence on the equivalent stress, equivalent strain, maximum shear stress and maximum shear strain and which design of thread form generates more maximum equivalent stress and strain. 3-D finite element analysis was used to evaluate the stress and strain patterns of three tread types. The results of this study were as follow. 1. Under the 200N of axial load, the value of maximum equivalent stress is smallest in square thread and there is no significant difference between that of V thread and reverse buttress thread. 2. Under the 200N of axial load, the value of maximum equivalent strain is largest in V thread and smallest in square thread. 3. Under the 200N of axial load, the value of maximum shear stress is smallest in square thread and there is no significant difference between that of V thread and reverse buttress thread. 4. Under the 200N of axial load, the value of maximum equivalent strain is largest in V thread and there is no significant difference between that of square thread and reverse buttress thread. 5. Above results show that the square thread has special advantages in stress and strain compared with other thread types, especially in shear stess which is most determinant to implant-bone interface. Considering the superior biomechanical properties of square form implant, we presume that square form implant has better clinical results than the other types of implants in the same clinical conditions.

• Journal of Internet Computing and Services
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• v.10 no.3
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• pp.1-8
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• 2009

The primary tasks of a workflow management system specify workflow models with respect to resource, control-flow, data-flow, functional, and operational perspectives, and to enact their workcases (workflow instances). In terms of enacting workflow models, the essential criterion grading the quality of the system is "how much is the system able to guarantee the correctness of workflow models' enactment?". Particularly, the workflow determinacy problem, which may be caused by the interference of the control-flow and the data-flow specifications, is the most challenging issue in guaranteeing the correctness of the system. We are able to solve the problem by either of the following two approaches-analysis of workflow model and verification of workflow enactment. In the paper, we propose a technique that guarantee the system's correctness through verifying workflow enactment. In other words, the technique is able to detect the conflicts of control-flow and data-flow enactments existing on a workflow model, which causes the system to be non-determinant in enacting workflow models. Finally, by applying the technique to the e-Chautauque workflow management system developed by the authors' research group, we prove that the technique is a feasible solution for the workflow determinacy problem.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.99-106
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• 2020

The purpose of this study is to find out whether image similarity between celebrities and brands on social network service be a determinant to predict advertising effectiveness. To this end, an advertising effect prediction model for celebrity endorsed advertising was created and its validity was verified through a machine learning method which is a big data analysis technique. Firstly, the celebrity-brand image similarity, which was used as an independent variable, was quantified by the association network theory with social big data, and secondly a multiple regression model which used data representing advertising effects as a dependent variable was repeatedly conducted to generate an advertising effect prediction model. The accuracy of the prediction model was decided by comparing the prediction results with the survey outcomes. As for a result, it was proved that the validity of the predictive modeling of advertising effects was secured since the classification accuracy of 75%, which is a criterion for judging validity, was shown. This study suggested a new methodological alternative and direction for big data-based modeling research through celebrity-brand image similarity structure based on social network theory, and effect prediction modeling by machine learning.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.24-33
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• 2016

Background: Previous numerous studies on watershed scale demonstrated that the constructions of upper dams may influence the below dams due to modifications of flow regime and nutrient inputs. Little is known about how the dam constructions influence the downstream lakes or reservoirs in the regional scale. This study demonstrates how the construction of upper dam (i.e., Yongdam Dam) influences nutrient regime, trophic relations, and empirical models in Daechung Reservoir (DR). Yongdam Dam was constructed at the upstream region of DR in year 2000. Results: The analysis of hydrological variables showed that inflow and discharge in the DR were largely reduced after the year 2000. The construction of upper dam construction also resulted in increases of water temperature, pH and conductivity (as an indicator of ionic content) in the DR. Empirical models of TP-CHL and N:P ratio-CHL suggested that stronger responses of CHL to the phosphorus were evident after the upper dam construction, indicating that algal production at a unit phosphorus increased after the upper dam construction. Mann-Kendall tests on the relations of N:P ratios to TN showed weak or no relations ($t_{au}=-0.143$, z = -0.371, p = 0.7105) before the dam construction, while the relation of N:P ratios to TP showed strong in the periods of before- ($t_{au}=-0714$, z = -2.351, p = 0.0187) and after the construction ($t_{au}=-0.868$, z = -4.270, p = 0.0000). This outcome indicates that TP is key determinant on N:P ratios in the reservoir. Scatter Plots on Trophic State Index Deviations (TSIDs) of "TSI(SD) - TSI(CHL)" against "TSI(TP) - TSI(CHL)" showed that the dominance of clay turbidity or light limitation was evident before the upper dam construction [TSI(TP) - TSI(CHL) > 0 and TSI(SD) - TSI(CHL) > 0] and phosphorus limitation became stronger after the dam construction [(TSI(TP) - TSI(CHL) < 0 and TSI(SD) - TSI(CHL) > 0]. Conclusions: Overall, our analysis suggests that the upper dam construction modified the response of trophic components (phytoplankton) to the nutrients or nutrient ratios through the alteration of flow regime, resulting in modifications of ecological functions and trophic relations in the low trophic levels.

• Archives of design research
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• v.20 no.1 s.69
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• pp.79-88
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• 2007

A company's plan to reform its products' image cannot obtain expected results unless a color plan is included in the reformation plan. A color plan is essential since color conveys to customers much information on function, shape, and material quality of the product. In other words, color is the essential dimension or criteria that customers use when evaluating the quality of goods. Despite the importance of a color plan, companies in Korea are still behind in researching and receiving 'color information' compared to those in more advanced countries. Recognizing the importance of products color, many international companies constantly make their efforts to predict trendy colors and preferred styles of customers before they develop products. It is suggested that domestic companies invest more in color infrastructure to be more successful in making products which can catch the customers' eyes and emotion. Different life styles by age, income level, and gender would be only a few of many factors to be investigated to build color plans for a product. In this study, it is attempted to see the color tendency of young generation by gender, and also to analyze empirically the influence of product's color on its image and customers' behavior. The results are analyzed with frequency analysis, cross tabulation analysis, T-test, one-way ANOVA using SPSS Win 12. The results of this study show that color preference, product image and product attitude are influenced by product's color, and color is an important factor for forming additional emotional value together with the product's original functional value. Judging from the findings, it is recommended that a company undertake careful research before developing a product to find out how customers respond differently to products in different colors especially when the product belongs to the product category where color is considered to be a determinant factor in terms of choosing a brand.

• Korean Journal of Head & Neck Oncology
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• v.17 no.2
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• pp.131-138
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• 2001

Objectives: Alcohol intake has been reported to be a risk factor of laryngeal cancer. Since the aldehyde dehydrogenase 2 (ALDH2) genotype is a major determinant of personal alcohol drinking habit, there is a possibility that ALDH2 genotype would be a risk factor for laryngeal cancer. N-Acetyltransferase 2 (NAT2) is a detoxifying enzyme and its polymorphism has been reported to be related to the risk of many environmental cancers. However, studies on the associations between these two genotypes and laryngeal cancer risk are scarce. We have assessed the effects of alcohol intake and the genotype of ALDH2 and NAT2 on the risk of laryngeal cancer in Koreans. Materials and Methods: Eighty-four pathologically proven laryngeal cancer patients and 168 age matched controls were included as the study subjects. Information about alcohol intake and smoking habit was collected using a self administered questionnaire. ALDH2 and NAT2 genotypes were analyzed using PCR-RFLP methods. Results: Alcohol intake was significant as a risk factor for laryngeal cancer (OR : 2.58, 95% CI : 1.24, 5.36), especially for supraglottic laryngeal cancer (OR : 3.24, 95% CI : 1.02, 10.31). Personal drinking habit was closely related with personal smoking habit, which was a potent risk factor of laryngeal cancer. In a stratified analysis according to the level of cumulative smoking amount, drinking was significant neither in light smokers (equal or less than 30 pack-years) nor in heavy smoker (over 30 pack-years). The ALDH2 genotype was significantly associated with the risk of laryngeal cancer in a univariate analysis. The statistical significance, however, disappeared after adjusting alcohol intake using a multiple conditional logistic model. The NAT2 genotype was not significant as a risk factor for laryngeal cancer. Conclusion: Alcohol drinking and ALDH2 genotype would have indirect effects on laryngeal cancer by their correlations with cigarette smoking or with alcohol drinking. It is less likely that the NAT2 genotype would be a potent risk factor of laryngeal cancer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.565-577
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• 2020

This study empirically examined how a firm size affects the determinants of innovative activities using the data of the Korean Innovation Survey (KIS) 2016. With data from 2,003 firms in the manufacturing sector, we performed logistic regression analysis and zero-inflated negative binomial regression analysis. R&D expenditure and patent applications were used as proxies for innovative activity. The independent variables included the firm's characteristics variables such as the firm's age, tech-level industry, RDemp (R&D employee ratio), venture, export, and industrial characteristics variables such as networking, appropriability, and spillovers. The empirical findings are that there are some differences in firms' innovative activity determinants among the firms' size groups. Next, strategic appropriability has negative impacts on small firms' R&D expenditure and medium-firms' patents. Networking is an important determinant of innovative activity for all firms, except for large firms. Furthermore, in deciding R&D activities, small and medium-sized firms were significantly influenced by industrial characteristics as compared to that of large firms. Our findings suggest some R&D promotion policies. Policies fostering firms' technological interaction would allow firms to take advantage of technological spillovers and thus raise the probability of investing in R&D.

• The Journal of Industrial Distribution & Business
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• v.9 no.10
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• pp.39-50
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• 2018

Purpose - This study is to propose discriminative management strategies to long-term care facilities based on the empirical analysis after reviewing the effects of social support, perceived by long-term care facility employees, to service orientation. Research design, data, and Methodology - The research model designed social support, job stress, organizational commitment, and service orientation. The survey collected data from 453 customers in a long-term care facility in jeju. The SPSS 18.0 package was used for analysis. Results - First, social support for long-term care facility employees has a negative(-) effect to job stress. Test results, social support factors except appraisal support had a negative impact on job stress. Second, social support has a positive(+) effect to organizational commitment. Test results, informational support, tangible support and appraisal support had significant effects on organizational commitment. However, emotional support had a positive impact on affective commitment and normative commitment. Third, social support has a positive(+) effect to service orientation. Test results had a positive impact. Fourth, job stress has a negative(-) effect to organizational commitment. In the test results, employee's continuance commitment and normative commitment had significant negative effects in job stress. However, affective commitment had no significant impact. Fifth, job stress has a negative(-) effect to service orientation. Test results showed a negative impact. Conclusions - The study implies the following. First, that there should be a change in the social perception of long-term care facilities. 'Long-Term Care Insurance for The Elderly' was enacted to emphasize this responsibility for the elderly problems as a new system. Enactment of this Act was expected to improve the quality of life of the people by stabilizing the elderly life and reducing the burden of families. Therefore, long-term care facility system should be as efficient as possible for making plans for systematic and organizational support. Second, the efforts of facility managers to minimize job stress of employees is necessary. Accordingly, performing spontaneous work is required for a comfortable working environment and management. Third, the systematic education and training to employees for service oriented behavior of the facility will be required in the long term.

• Journal of Nutrition and Health
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• v.31 no.1
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• pp.36-45
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• 1998

Dietary and other factors affecting bone density of 32 Korean healthy college women aged 19-23 years were assessed. Data for food and nutrient intake was obtained by a semiquantitiative food frequency questionnaire. Serum samples were anlayzed for total Ca, P, Ca++, PTH, calcitonin and 25-hydroxycholecalciferol , (25-OH-Vit D3) and BMDs of lumbar spine(L2-L4), femoral neck(FN), ward's triangle (WT) and trochanter(TR) were measured by an XR-series X-ray bone densitometer. Relationships between the factors and BMDs were analyzed by stepwise multiple regression analysis and Pearson's correlation coefficient(r). The results are summarized as follows. Mean daily intake of energy(86.1%), Ca(74.3%), vitamin A (53.75), Fe(49.75) and vitamin B$_2$(86.6%) were lower while other notrients incuding P(126%) were higher than the Korean RDA. The BMDs of lumbar spines and femurs ranged from 0.73g/$\textrm{cm}^2$ to 1.23g/$\textrm{cm}^2$and 0.48g/$\textrm{cm}^2$ to 1.04g/$\textrm{cm}^2$, respectively. Both protein and P intakes were inversely associated with serum total Ca. Furthermore, Ca intake as well as Ca/P ratio (Ca/P) were inversely associated with serum ionized Ca(Ca++) concentration. The intakes of protein P and Ca , however, were not significantly associated with the BMDs measured in this study. There were little association between BMDs and alcoholic beverage or caffeine consumption. The only significant association detected was a positive relationship between caffeine consumption and BMD of WT. It seemed to be noticeable that BMDs of L2-L$_4$, FN and WT were significantly inversely associated with serum P concentration. However, there was no significant association between BMDs and the levels of total Ca to Ca++ in serum. Body weight was positively associated with BMD of lumbar spine and BMI was also positively associated with BMDs of FN and WT. The subjects who had an early menarche appeared to have higher BMDs than those who had had a late mearche. According to stepwise multiple regression analysis. Menarche and BMI were stronger determinants of BMDs in the young women than was diet. P intake appeared to be a more potent dietary determinant than Ca intake. The three factors, menarche, BMI , and P intake , additionally accounted for 24% and 378% of the variance in BMDs of FN and L$_2$-L$_4$, respectively. Further investigation is necessary to determine the factors needed to increase serum P level which negatively affects. BMD in young Korean college women.

• Journal of Digital Convergence
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• v.11 no.4
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• pp.351-359
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• 2013

This study was conducted to investigate the factors that affect the length of stay in hospital for schizophrenic patients. Of the data from the in-depth injury patient surveillance system, the final subject included 2,239 patients with schizophrenia in their final diagnosis. Using SPSS 18.0, a hierarchical regression analysis was performed by sequentially entering the explanatory variables by setting sociodemographic characteristics, discharge characteristics and hospital characteristics as explanatory variables and the length of stay in hospital as a dependent variable. The findings showed that the sociodemographic characteristics had the highest explanatory power and the explanatory power changed when the explanatory variable of the hospital characteristics was added, as opposed to the discharge characteristics. Male, type-1 medicaid, Chungcheong-do and the number of beds were found to be the factors that mostly affect the length of stay. Since this study used the secondary data, it has a limitation in terms of additional variables that could better explain the length of stay for schizophrenic patients. Nevertheless, it has an implication in that it investigated a large scale of data on a national level. For the effort of reducing the length of stay, it is suggested that an effort should be made at the national level, by focusing more on the hospital characteristics as well as the individual characteristics of patients.