• Journal of Korea Water Resources Association
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• v.40 no.10
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• pp.755-768
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• 2007

The purpose of this study is to analyse the characteristics of Manning's roughness coefficient according to change of discharge by using observed data obtained from a stable gravel-bed river and to investigate the applicability of the relevant existing empirical methods to it. Observed water level and discharge data are used as input data for the USGS computer program NCALC model for calculation of the roughness coefficient. Calculated values are compared with roughness values which are estimated with four widely used methods. The results show that though the empirical methods are able to give similar roughness values only for flood flow, they seem to have rather high uncertainty because of necessity of subjective judgement and differences of resultant values. Roughness coefficients for normal-low flow cannot be estimated from the existing empirical formulae. Especially, using the Manning equation for calculating them should be careful as this provides a wide range of estimated values in normal-low flow. The relations between the roughness coefficient and characteristic size of bed materials are different from them in flood flow even though they have a close relations.

• Culinary science and hospitality research
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• v.15 no.2
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• pp.219-230
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• 2009

The purpose of this research was to investigate the success factors of the foodservice franchise business. This study examined relevant literatures, set up some hypotheses to solve main questionable consideration and made a corresponding empirical analysis. For the empirical analysis, a questionnaire survey was applied to ttotal 120 franchisers who have operated franchise business around Seoul. The result from the multiple regression model shows that the success of the franchise business is influenced by the operating system, the brand system, the educational system, and the franchisees' activities. As mentioned in the literature review and empirical analysis, it is found that the above mentioned four systems are equally affected by franchisers' success factors. The limits of this study include the fact that it has selected and researched around Seoul and four factors. Future research should be done from the perspective of such factors as culture, economy, region, menu, service and so on.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.4
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• pp.115-136
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• 2014

The game industry has grown steadily and the online game has become one of the most attractive game segments for its remarkable growth. Customer management in the online game industry, however, has received little attention from the academic field. The purpose of this study is to analyze the drivers of customer defection in the online game setting and suggest not only theoretical but also managerial insights into increasing customer retention rates. Prior to empirical analysis, the authors hypothesized that 3 variables of interests (Learning, Playing, Achievement) would explain the customer defection according to preceeding researches. To demonstrate these hypotheses, the authors obtained data from one of the biggest game publishers in Korea, and the empirical analysis model was developed considering context of research settings. The results of analyses provide the following insights. First, the key behavioral variables of Learning, Playing, and Achievement play substantial roles in explaining the customer defection. Next, the effects of these variables vary between customer types: novice and experienced customers. The defection decisions by novice customers are predicted by all key behavioral variables and Playing serves as the most influential indicator of the defection decisions. However, experienced customers are influenced by Playing and Achievement, while Learning has no impact on the defection decisions. Finally, the authors investigated hypothetical customer retention strategies, using the empirical results. The market outcomes indicate that the customer retention strategies work well with novice customers and it is hard-to-impossible to prevent experienced customers from defection using their behavioral data. These findings together deliver several meaningful insights to management as follow. First, the management should support customers to get involved in Learning activities at the very first stage. Second, customer's Achievement and appropriate compensation for it would work as defection barriers. Last, to optimize the outcomes of firm's marketing investments, it is better to focus on retention of novice users not experienced ones.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.1-18
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• 2017

Temperature-dependent development model is an essential component for forecasting models of insect pests as well as for insect population models. This study reviewed the nonlinear models which explain the relationship between temperature and development rate of insects. In the present study, the types of models were classified largely into empirical and biophysical model, and the groups were subdivided into subgroups according to the similarity of mathematical equations or the connection with original idea. Empirical models that apply analytical functions describing the suitable shape of development curve were subdivided into multiple subgroups as Stinner-based types, Logan-based types, performance models and Beta distribution types. Biophysical models based on enzyme kinetic reaction were grouped as monophyletic group leading to Eyring-model, SM-model, SS-mode, and SSI-model. Finally, we described the historical development and characteristics of non-linear development models and discussed the availability of models.

• Korea Journal of Hospital Management
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• v.23 no.2
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• pp.95-105
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• 2018

Objective: This study conducted an empirical research on foreign patients who had visited the medical institutions of Daegu region in order to identify the effects of the factor satisfaction and experience satisfaction with medical services on their revisit intentions. Methods: This study reviewed the existing studies on medical services to foreign patients with a main focus on medical tourism, and conducted the empirical research through a survey on foreign patients from the Russian, Chinese and English-speaking regions based on the Daegu Medical Tourism Promotion Institute's DB of foreign patients. The empirical research conducted a multiple regression analysis on factor satisfaction and experience satisfaction regarding return visit intentions. Results: The multiple regression analysis results showed that both the factor satisfaction and the experience satisfaction with medical services of foreign patients had positive effects on their return visit intentions, especially, with a relatively greater effect from the factor satisfaction. Specifically, it was found that factor satisfaction elements of 'friendliness of employees', 'good communication', and 'expertise of medical workers'; and experience satisfaction elements of 'reliability of medical information', 'efforts to minimize incompatibility towards foreigners', 'convenient access to medical information' and the like enhanced the return visit intentions. Conclusion: We discovered that, in the context of medical tourism activities, it is important to enhance factor satisfaction and experience satisfaction with medical services in order to promote return visits of the foreign patients who we once attracted. Especially, there are implications that reliability of medical information and efforts to minimize incompatibility towards foreigners enhance return visits of foreign patients.

• Korean Journal of Health Education and Promotion
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• v.33 no.1
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• pp.13-22
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• 2016

Objectives: By using six years of KNHANES dataset (2008~2013) about 60 ages older people, we analyzed how the depression prevalence rate in the elderly is influenced by disease and activity limit. Especially, to add a sense of more reality, we adopted stress experience as a control variable to see how the depression prevalence rate in the elderly is influenced by disease and activity limit depending on the stress experience. Methods : We adopted six years of KNHANES dataset, indicating that our results were based on long period of time capable of considering temporal patterns in the depression prevalence rate in the elderly. Total 1,160 elderly people in KNHANES were selected for our empirical analyses. Dependent variable is either 0 or 1 depending on whether the elderly people feel depression. Main explanatory variables for our study include disease and activity limit. Logistic regression analysis was applied for two group such as stress experience and non-experience. Results : According to the empirical results, stress factor is found to be significant in explaining the depression in the elderly. Depression prevalence rate increased when the elderly has stress experience: chronical disease(OR=1.650), chronical disease with activity limit(OR=3.388), non-chronical disease with stress(OR=11.841) chronical disease with stress (OR=13.561) and chronical disease with activity limit and stress(OR=28.691). Conclusions: The finding suggest that the Countermeasures of elderly's depression alleviation should include stress management.

• Journal of Distribution Science
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• v.16 no.1
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• pp.37-46
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• 2018

Purpose - This study is to investigate the effects of consumption motives of restaurant customers on the perception of the importance of restaurant attributes, and to determine the influence of the consumption motives on the empirical and functional attributes between Vietnam and Korea. Research design, data, and methodology - Questionnaire items from previous studies were revised to fit the research purpose of the present study. From August 1 to August 25, 2017, questionnaires were simultaneously administered in Korea and Vietnam using both on-line and off-line survey methods (including SNS and e-mail). With 381 surveyed questionnaires in Vietnam(219) and Korea(162), this study was conducted by using SPSS 22.0 to verify the reliability and validity of the measured variables. Structural equation model (SEM) was employed as a statistical method for the hypotheses test of this study. Results - The results showed that hedonic eating-out motive has more influence on the importance of empirical attribute than that of functional attribute in restaurant. In addition, utilitarian eating-out motive has more influence on functional attributes than empirical attributes. However, these relationships showed the difference between countries in Vietnam and Korea. As for in Korea, consumers' hedonic and utilitarian motives of eating-out were more influential on experimental and functional attributes. Conclusions - This study analyzed the influence on the importance of the eating-out motives of restaurant attributes and how this differed between Vietnamese and Korean.

• International Commerce and Information Review
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• v.15 no.1
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• pp.333-356
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• 2013

The main purpose of this article is to find out the determinants of usage and performance of the uTradeHub system in Korean SMEs. To achieve the purpose of the study, the research model and the hypotheses were developed based on the previous research on uTradeHub and e-Trade. And to test the research hypotheses, empirical survey was conducted to Korean SMEs which were using uTradeHub services. The results of the empirical analyses are as follows. First, among the external factors, intra-industry competition and transaction intensity were significant determinants of uTradeHub usage level. Secondly, among the internal factors, only CEO's support was found to be a significant determinant. Thirdly, among the IT related factors, IT infrastructure and IT training were positively related to uTradeHub usage level. Finally, the uTradeHub usage level was found to have positive effect both on financial and non-financial export performance of the Korean SMEs.

• Nuclear Engineering and Technology
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• v.14 no.3
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• pp.103-109
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• 1982

An empirical formula for determining water content as functions of uranium concentration and nitric acid normalities in uranyl nitrate solutions has been derived from a least-squares analysis of experimental data, i.e., uranium concentration, nitric acid normalities and solution densities for a large number of UO$_2$(NO$_3$)$_2$ solutions. The formula derived is Q=1-0.3628C-0.0327H$^{+}$ where Q, C, and H$^{+}$ stand for water content (g/cc), uranium concentration (g/cc), ana nitric acid normality, respectively. Atom number densities and nuclear criticality for hypothetical uranyl nitrate solutions have been calculated by using the empirical formula, ana compared with the results obtained on the basis of uranium concentration, nitric acid normality, and solution density. The empirical formula derived in this study seems to be useful in uranium concentrations ranging from 0.295g/cc down to 0.004g/cc and nitric acid normality from 5.06 to 1.00..00.

• Journal of Navigation and Port Research
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• v.42 no.1
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• pp.39-46
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• 2018

Strategic partnerships of alliances and large shipping companies have been steadily launched in shipping market. Converting these alliances into customers and maintaining them important hub port status. The cases of container terminals to establish a political strategy based on. On the other hand, bulk terminals are relatively unexplored container terminal and bulk terminal are included in the same category of port empirical research from the overall perspective. Therefore, analysis of structural equations was utilized in this study. Analysis of the entire measurement model showed that all items except "Results - Intention of renewal" on bulk terminals were significant. This study is expected to contribute to promotion of empirical studies in various levels by compare container terminals and bulk terminals.