• The Korean Journal of Applied Statistics
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• v.19 no.3
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• pp.407-419
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• 2006

In this paper, we analyze household overdue loans in Korea which has been causing serious social and economical problems. We consider customers of Bank A in Korea and focus on overdue cash services which have been snowballing in the past few years. From analysis of overdue loans, one can predict possible delays for current customers as well as build a credit evaluation and risk management system for future customers. As a statistical analytical tool, we propose a two-stage Generalized Linear regression Model (GLM) which assumes a logistic model for presence/non-presence of overdue and a gamma model for the amount of overdue in the case of overdue. We perform goodness of fit test for the two-stage model and select significant explanatory variables in each stage of the model. It turns out that age, the amount of credit loans from other financial companies, the amount of cash service from other companies, debit balance, the average amount of cash service, and net profit are important explanatory variables relevant to overdue credit card cash service in Korea.

• Journal of the Economic Geographical Society of Korea
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• v.14 no.2
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• pp.157-175
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• 2011

This paper aims to analyze the characteristics of healthcare REITs' performance and operation, and to examine their use for activating the silver industries in Korea. The results of this study are as follows. First, according to the results of analyzing healthcare REITs' performance, healthcare REITs outperformed average REITs and extended investment proportion compared to total REITs after 2007. This outperforming came from not only rapid growth of silver industries, but also REITs strategy using the structure of sale-and-leaseback and triple-net lease. Second, healthcare REITs use selection and concentration strategy in terms of asset sector, but use portfolio diversification strategy in terms of investment region. Third, according to the analysis results, healthcare REITs are to be useful for activating the silver industries in Korea. In this context, major implications are presented to use healthcare REITs effectively.

• Survey Research
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• v.10 no.2
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• pp.97-114
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• 2009

Even the importance and necessity of a basic national statistical survey, the population and housing census is facing with some practical difficulties such as higher survey cost, decrease of survey information and much longer survey period. As an alternative to the traditional census for tackling such difficulties, a rolling census has been introduced. The rolling census has some advantages such as improved timeliness with much more frequent data and evenly distributed survey cost over several years. On the contrary, the rolling census has also some disadvantages such as the lost of snapshot feature of the population and increasing risk of outside influence on field work. In this paper we reviewed the French rolling census and the American community survey as roiling surveys, and then investigated some factors like balanced sample selection, population update, synthetic estimation, and the operation of rolling survey, which are to be checked carefully in case of introducing a rolling census as an alternative to the current census.

• Journal of Korea Multimedia Society
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• v.14 no.7
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• pp.933-939
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• 2011

Recent heavy rains have caused natural disasters such as flooding and landslides nationwide. Because of flooding occurrence in most of the roads, traffic congestion and isolation caused many loss especially at rush hour. Constant monitoring and analysis of past disaster history data are needed to prevent disasters on areas prone to floods and disaster risk areas. If we managed to obtain traffic volume, speed, phase around intersection using disaster history data when disasters occurred, we can analyse traffic congestion, change of disaster scale and rainfall. In this study, We select a target district to develop by using a route from Dae-nam intersection in Busan Namgu Daeyoeon-dong, over Gwangan large bridge up until Haeundae Olympic intersection, We developed a system which searches disaster history information, traffic volume using disaster history data based on user selection of the road.

• Journal of Korean Neurosurgical Society
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• v.52 no.4
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• pp.320-324
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• 2012

Objective : The purposes of this study are to investigate the factors that may be related to ventriculoperitoneal (VP) shunt in patients with cerebellar hematoma and the effect of severe fourth ventricular hemorrhage, causing obstructive hydrocephalus on subsequent VP shunt performance. Methods : This study included 31 patients with spontaneous cerebellar hematoma and concomitant fourth ventricular hemorrhage, who did not undergo a surgical evacuation of hematoma. We divided this population into two groups; the VP shunt group, and the non-VP shunt group. The demographic data, radiologic findings, and clinical factors were compared in each group. The location of the hematoma (whether occupying the cerebellar hemisphere or the vermis) and the degree of the fourth ventricular obstruction were graded respectively. The intraventricular hemorrhage (IVH) score was used to assess the IVH severity. Results : Ten out of 31 patients underwent VP shunt operations. The midline location of cerebellar hematoma, the grade of fourth ventricle obstruction, and IVH severity were significantly correlated with that of VP shunt operation (p=0.015, p=0.013, p=0.028). The significant variables into a logistic regression multivariate model resulted in statistical significance for the location of cerebellar hemorrhage [p=0.05; odds ratio (OR), 8.18; 95% confidence interval (CI), 1.00 to 67.0], the grade of fourth ventricle obstruction (p=0.044; OR, 19.26; 95% CI, 1.07 to 346.6). Conclusion : The location of the cerebellar hematoma on CT scans and the degree of fourth ventricle obstruction by IVH were useful signs for the selection of VP shunt operation in patients with spontaneous cerebellar hematoma and concomitant acute hydrocephalus.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.501-522
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• 2016

In the digital era, information is a source of value creation. However, the growing importance of knowledge and information also increases risks and threats. When information is leaked, full recovery is difficult, and additional spreading of risk is high because it is easy to accomplish. Especially personal information is the main target due to its availability. Although individuals normally have to consent to the use of their personal information, they often do not know the use of their information. In such a difficult situation, one must exercise self-determination and privacy. Therefore, the goal of this study is to development a privacy literacy level measurement model for the proper exercise of the right to informational self-determination. It will be presented with the concept of privacy literacy index in order to determine the level of knowledge and understanding and practical application skills for individual. Through the index, we going to enhance the selection ability of information subject, and to promote the judgement and the determination capability for the protection and utilization of personal information.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1304-1309
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• 2005

The production of therapeutic proteins for human diseases in plants results in many economic benefits, including reduced risk of animal virus contamination, high yields, and reduced production and storage costs. Human cytokines, interleukin-11 (hlL-11) and granulocyte-macrophage colony-stimulating factor (hGM-CSF), cDNAs were introduced into rice or tobacco, using either the maize ubiquitin promoter or the 35S promoter. The primary hIL-11 transgenic rice plants exhibited stunted growth and a sterile phenotype, whereas the hIL-11 transgenic tobacco plants did not. This suggests that hIL-11 expression in rice disrupts the normal growth and development of the plant. The regeneration efficiency of rice calli transformed with hGM-CSF was found to be approximately a quarter of that seen with the hIL-11, suggesting that hGM-CSF expression is more deleterious to the regeneration of rice calli than is hIL-11. However, the surviving hGM-CSF transgenic rice plants exhibited a normal phenotype of growth. Therefore, it appears that only those transgenic rice lines that expressed the human cytokines in small quantities were able to survive the selection process.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.4
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• pp.261-276
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• 2002

Recently, for the purpose of choosing reasonable and economical construction, the decision making analyses, such as VE (Value Engineering) and LCC (Life Cycle Cost), are generally performed. But, these methods have some limitations for the application to subway tunnel construction method. So, the AHP (Analytical Hierarchy Process) analysis is applied to determine relative importance for obtaining objectivity in quantitative analysis. And, the LCSC (Life Cycle Social Cost) method is developed to account for the social loss and risk by tunnel construction. From the case of the subway ${\bigcirc}{\bigcirc}$ lot, those methods are very useful to decision making analysis. And, in that case, both quantitative and quantitative analysis appraisement, the drilling and blasting method is evaluated useful alternative proposal in comparing with the cut and cover method.

• Journal of KIISE:Software and Applications
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• v.29 no.11
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• pp.785-794
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• 2002

Automatic stock trading systems should be able to solve various kinds of optimization problems such as market trend prediction, stock selection, and trading strategies, in a unified framework. But most of the previous trading systems based on supervised learning have a limit in the ultimate performance, because they are not mainly concerned in the integration of those subproblems. This paper proposes a stock trading system, called R-Trader, based on reinforcement teaming, regarding the process of stock price changes as Markov decision process (MDP). Reinforcement learning is suitable for Joint optimization of predictions and trading strategies. R-Trader adopts two popular reinforcement learning algorithms, temporal-difference (TD) and Q, for selecting stocks and optimizing other trading parameters respectively. Technical analysis is also adopted to devise the input features of the system and value functions are approximated by feedforward neural networks. Experimental results on the Korea stock market show that the proposed system outperforms the market average and also a simple trading system trained by supervised learning both in profit and risk management.

• Environmental Analysis Health and Toxicology
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• v.24 no.2
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• pp.137-148
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• 2009

This study quantitatively investigated the emissions of indoor air pollutants associated with the utilization of air fresheners indoors, and evaluated individual exposure to five specified indoor air pollutants, which were chosen on the basis of selection criteria. An electrically-polished stainless steel chamber (50L) was employed to achieve this purpose. Test air fresheners were selected through three steps: first, on the basis of market sales; second, on the basis on a preliminary head-space study; and lastly, on the basis of emissions of toxic compounds (benzene, ethyl benzene, limonene, toluene, and xylene). The empirical mathematical model fitted well with the time-series concentrations in the environmental chamber (in most cases, determination coefficient, $R^2{\gtrsim}$0.9), thereby suggesting that the empirical model was suitable for testing emissions. The concentration equilibrium appeared 180 min after the introduction of sample air fresheners into the chamber. Both the chamber concentrations of emission rates or factors varied greatly according to air freshener type. It is noteworthy that although benzene, ethyl benzene, toluene, and xylene were emitted from all test air fresheners, their exposure levels were not significant enough to result in any significant health risk. However, certain type of air fresheners were observed to emit significant amount of limonene, which is potentially reactive with ozone to generate secondary pollutants with oxidants such as ozone, hydroxyl radicals, and nitrogen oxides. The exposure levels to limonene associated with the utilization of three air fresheners were estimated to be 13 to 175 times higher than that of other air fresheners. This information can help consumers to select low-pollutant-emitting air fresheners.