• KDI Journal of Economic Policy
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• v.40 no.1
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• pp.31-43
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• 2018

There is a large amount of empirical literature reporting that people who regularly attend religious services tend to have better health outcomes. However, it remains an unanswered question as to whether the observed correlation reflects any causality. Exploiting exogenous changes in church attendance driven by law changes in 21 states of the U.S., I find tentative but suggestive evidence that the observed strong correlation between religious participation and health is likely to be driven by endogenous selection.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.427-431
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• 1994

The objective of this paper is to provide an inventory control policy for the system that carries a single item with a multiple demand classes, when the demand is Poisson distributed random variable. The inventory control process includes the process of determining the reorder point, and the process of inventory control during the lead time. The goal of the optimization process is to achieve the service level of each demand class as well as the system-wide total service level at a preset desired service level while sustaining a minimum average inventory.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.3
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• pp.194-200
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• 2005

A stochastic dynamic lot sizing problem for multi-item is suggested in the case that the distribution of the cumulative demand is known over finite planning horizons and all unsatisfied demand is fully backlogged. Each item is produced simultaneously at a variable ratio of input resources employed whenever setup is incurred. A dynamic programming algorithm is proposed to find the optimal production policy, which resembles the Wagner-Whitin algorithm for the deterministic case problem but with some additional feasibility constraints.

• Journal of Korean Institute of Industrial Engineers
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• v.11 no.2
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• pp.29-37
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• 1985

This paper studies a production-inventory model which unifies the inventory problem of raw materials and the finished product for a single product manufacturing system. The integrated production-inventory model is formulated wth a nonlinear mixed integer programming problem. An algorithm is developed by utilizing the finite explicit enumeration method. The algorithm guarantees to generate an optimal policy for minimizing the total annual variable cost. A mumerical example involving 15 raw materials is given to illustrate the recommended solution procedure.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.8 no.1
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• pp.23-47
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• 2000

Purpose of this paper is to enhance aviation safety in korea through comparison with aviation safety policies implemented by other countries. it can be another opportunity for Korean two national flag airlines to reappraise and reinforce the significance of "aviation safety", as well as set forth immediate vigorous efforts to support the government's aviation safety enhancement countermeasures. I hope this study would contribute and provide a variable idea and direction to enhance aviation safety management of two Korean flag carriers.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.2
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• pp.289-298
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• 1995

We consider a general queueing network with multi-server stations. The stations are under heavy traffics or moderate variable conditions. We develope an algorithm to determine the optimal loading policy, which minimizes the congestion in a network. Under more specified condition, majorization and arrangement orderings are established to compare, respectively, various loading and assignment policies. Implications of results are also discussed.

• Restorative Dentistry and Endodontics
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• v.44 no.1
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• pp.11.1-11.8
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• 2019

In the previous sections, simple linear regression (SLR) 1 and 2, we developed a SLR model and evaluated its predictability. To obtain the best fitted line the intercept and slope were calculated by using the least square method. Predictability of the model was assessed by the proportion of the explained variability among the total variation of the response variable. In this session, we will discuss four basic assumptions of regression models for justification of the estimated regression model and residual analysis to check them.

• Industrial Engineering and Management Systems
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• v.13 no.3
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• pp.330-341
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• 2014

An instrument which practitioners have acknowledged as an essential mechanism used in supporting greenhorn companies is the business incubation system. Several countries of the world have implemented the business incubation concept ever since it was conceived and developed in the United States in 1959. It is a model that has typically given itself much more readily within industrialized countries with identical environments to the United States. Nigeria also adapted it in 1993 where the resulting process and practice failed to live up to anticipations. To determine the significant role of government policy on the incubation dimensions and its success is the purpose of this research. Data collection process involved the surveying of stakeholders in Nigeria with some direct involvement in the national programme. The Partial Least Squares (PLS) was employed for the analysis. The findings showed that all exogenous variables collectively explained 52.4% of the variance in success. Meanwhile, when a moderation effect is present; the variable increased to 62.3%. Consequently, it is recommended that for a business incubation scheme to be successful and effective, government needs to implement efficient policies since results showed that these policies influenced all the relationships. The results' implications as well as limitations of the study are discussed.

• The Journal of Information Systems
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• v.22 no.4
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• pp.49-69
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• 2013

Recently, enterprises have reinforced security control in order to prevent infringement of personal information and abuse of customer information by insiders. However, the reinforcement of security control by enterprises makes it difficult for internal users to perform business by using a business information system. There is, therefore, a need for research on various fields, which makes it possible to establish an appropriate security control policy while minimizing an impact on business. The present research verifies and analyzes an impact on difficulty in business of internal users using customer information, which is caused by security control performed by display restriction on customer information identifiers. The present research is intended to academically develop a technique for statistically analyzing an impact degree and a causal relationship between security control and an impact on business, which is a dichotomous variable, and to practically contribute to the establishment of an efficient security policy in consideration of an impact on business when an enterprise applies security control. A research target was internal business information systems of domestic securities enterprises, data was collected by questionnaire, and verification/analysis was performed by logistic regression analysis.

• Health Policy and Management
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• v.26 no.1
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• pp.30-38
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• 2016

Background: This study purposed to analyze the relationship between spatial distribution of Diabetes prevalence rates and regional variables. Methods: The unit of analysis was administrative districts of city gun gu. Dependent variable was the age- and sex- adjusted diabetes prevalence rates and regional variables were selected to represent three aspects: demographic and socioeconomic factor, health and medical factor, and physical environment factor. Along with the traditional ordinary least square (OLS) regression analysis, geographically weighted regression (GWR) was applied for the spatial analysis. Results: Analysis results showed that age- and sex-adjusted diabetes prevalence rates were varied depending on regions. OLS regression showed that diabetes prevalence rates had significant relationships with percent of population over age 65 and financial independence rate. In GWR, the effects of regional variables were not consistent. These results provide information to health policy makers. Conclusion: Regional characteristics should be considered in allocating health resources and developing health related programs for the regional disease management.