• Journal of Korea Water Resources Association
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• v.54 no.spc1
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• pp.1183-1193
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• 2021

Low flow affects various fields such as river water supply management and planning, and irrigation water. A sufficient period of flow data is required to calculate the Flow Duration Curve. However, in order to calculate the Flow Duration Curve, it is essential to secure flow data for more than 30 years. However, in the case of rivers below the national river unit, there is no long-term flow data or there are observed data missing for a certain period in the middle, so there is a limit to calculating the Flow Duration Curve for each river. In the past, statistical-based methods such as Multiple Regression Analysis and ARIMA models were used to predict sulfur in the unmeasured watershed, but recently, the demand for machine learning and deep learning models is increasing. Therefore, in this study, we present the DNN technique, which is a machine learning technique that fits the latest paradigm. The DNN technique is a method that compensates for the shortcomings of the ANN technique, such as difficult to find optimal parameter values in the learning process and slow learning time. Therefore, in this study, the Flow Duration Curve applicable to the unmeasured watershed is calculated using the DNN model. First, the factors affecting the Flow Duration Curve were collected and statistically significant variables were selected through multicollinearity analysis between the factors, and input data were built into the machine learning model. The effectiveness of machine learning techniques was reviewed through statistical verification.

• 한국벤처창업학회:학술대회논문집
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• 2019.04a
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• pp.51-55
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• 2019

기업신용평가(ICR : Issuer Credit Rating)는 기업의 금융상 채무에 대한 전반적인 적기 상환능력, 즉 채무불이행의 가능성을 평가한 것으로 오로지 금융상 채무에 대한 전반적인 채무상환능력을 평가한다. 최근에는 신용평가 등급이 금융시장과의 효과적인 의사소통수단으로 인식되고 기업 IR 및 홍보차원과 기업 간 물품공급과 납품을 위한 업체 선정시 신용등급이 적극적이고 다양하게 활용되고 있다. 이러한 기업신용평가는 최근 경제환경의 급속한 변화에 대응하여 기관별로 평가시스템을 자주 개선하고 있다. 본 연구에서는 정책금융기관 별로 변화된 평가시스템에 대한 평가지표나 구조, 평가시스템을 비교 분석해 그 차이점과 공통점 그리고 경제환경 변화에 따라 변화된 주요지표를 파악해 보고 미래의 신용평가시스템의 변화와 개선방안에 대해 생각하였다. 기관별 비교에서 평가시스템의 차이점은 신보는 신용평가(부실률 기반)와 미래성장성평가(성장성 기반)를 실시하여 보증심사등급(보증의사결정 등급)을 산출하고, 기술자산평가등급은 신용평가등급을 조정(최대 ${\pm}2$등급)하는 보조적 수단으로 활용하고 있으며, 기보는 기술평가(성장성 및 부실률 기반)와 리스크관리용 리스크평가(신보의 신용평가에 해당)로 평가체계를 이원화하여 운영하고, 평가모형은 신보는 객관성을 확보한 정량평가 위주, 기보는 공신력을 확보한 정성평가 위주의 주관적인 평가를 실시하고 있어 어떤 형태의 평가시스템이 더 좋은 평가방법 인지는 알 수 없지만, 기관별 부실율을 보면 다소 참고가 될 수도 있으나, 이것이 전적인 평가의 문제라 보기도 어렵다. 특히 신보는 창업기업 기준이 창업후 7년까지로 확대됨에 따른 창업 3단계 평가제도와 기업의 성장단계에 맞춘 성장단계별 평가기준 세분화는 기업환경을 잘 반영한 변화라 볼 수 있다. 그리고 향후 평가시스템은 경제환경의 변화속도를 어떻게 잘 반영 할 수 있는지에 대한 연구로 방향이 전개될 것으로 보인다.

• Journal of the Korean Society for information Management
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• v.17 no.3
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• pp.7-20
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• 2000

Many organizations have developed their own information systems not only for internal efficiency but also for effectiveness of external customer services. The infusion of powerful information networks into business environments is beginning to have a profound impact on the nature of governance between buyers and sellers in the market place. One of the most effective service tools for their customers is the use of information technology. The web technology is rapidly becoming one of the most effective online customer service tools toward strategic competitive advantage. In order to gain competitive edge, organizations must have effective web sites for customer services. A study on web service development phase has been conducted and present states of web usages by Korean, US., Japanese companies are surveyed. Cases of business web sites are empirically analyzed in order to compare the different levels of web site application in three countries. Conclusively, countries with longer experience with internet has more advanced level of web application such as business transaction and internet process innovation. In order to support effective web site planning, organizations have to understand their current position in Internet application and form strategies for e-business.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.255-260
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• 2007

The construction industry has been recognized as lagging behind other industries in the area of research and development (R&D) due primarily to the lack of R&D funds. To overcome this situation, the Korea Ministry of Construction and Transportation has a plan to expand its investments on the construction R&D up to 1.72 billion US dollars over the next 3 years. Despite this effort, it is still challenging to conduct the quantitative measurement on the efficiency of construction R&D projects, which can be utilized as the objective basis in the reasonable selection of a promising R&D team or in the consequential evaluation of a R&D performance. This study aims to conduct the efficiency analysis on the construction R&D projects to provide the basis for evaluating the performance of research and development. Toward this end, this study performs an efficiency analysis, which reflects all of the input and output data into/from the construction R&D by utilizing the Data Envelopment Analysis (DEA). The proposed methodology can be utilized to make a better decision on the priority of the R&D investments and present a sound basis to suggest the areas to be improved so as to reduce the inefficiency of R&D projects.

• The Korean Journal of Applied Statistics
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• v.31 no.6
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• pp.771-783
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• 2018

The life insurance industry is interested in various factors that influence the long-term extensions of insurance contracts such as the necessity for the advisors' long-term management of consumers, product consulting, and improvement of the investment aspects. This paper investigates important factors leading to a long-term contract that forms an important part of the life insurance industry in Korea. For this purpose we used the data of contents (i.e., data from Jan 1, 2011 to Dec 31, 2016) of the contracts of xxx insurance company. In this paper, we present how to select important variables to influence the duration of the contract maintenance via a penalized Cox's proportional hazards (PH) modelling approach using insurance life data. As the result of analysis, we found that the selected important factors were the advisor's status, the reward type 2 (annuity insurance) and tendency 4 (safety-pursuing type).

• Science of Emotion and Sensibility
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• v.9 no.2
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• pp.141-150
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• 2006

Since the late 1990s, 'smart clothing' has been developed in a various way to meet the need of users and to help people more friendly interact with computers through its various designs. Recently, various applications of smart clothing concept have been presented by researchers. Among the various applications, smart clothing with a health care system is most likely to gain the highest demand rate in the market. Among them, smart clothing for check-up of health status with its sensors is expected to sell better than other types of smart clothing on the market. Under this circumstance, research and development for this field have been accelerated furthermore. This research institution has invented biometric sensors suitable for the smart clothing, and has developed a design to diagnose various diseases such as cardiac disorder and respiratory diseases. The newly developed smart clothing in this study looks similar to the previous inventions, but people can feel more comfortable in it with its fabric interaction built in it. When people wear it, the health status of the wearers is diagnosed and its signals are transmitted to the connected computer so the result can be easily monitored in real time. This smart clothing is a new kind of clothing as a supporting system for preventing various cardiac disorder and respiratory diseases using its biometric sensor built-in, and is also an archetype to show how smart clothing can work on the market.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.196-206
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• 2009

The profitability of a hospital refers to business administration results achieved through its medical care and other management activities during applicable fiscal year. This study focused on operating margin as a measurement index of hospital profitability, which is a genuine medical return obtained by subtracting medical expenses from medical profits achieved during business administration of hospital. Based on the index, this study could deduce certain factors on hospital profitability in terms of various indices affecting profitability. And based on those factors, this study sought to provide more useful reference materials which allow us to devise possible ways to improve hospital profitability. As a result, it was found that public hospitals attained lower profitability than private ones. To analyze profitability depending on each index, this study divided hospitals broadly into deficit group and surplus group. As a result, it was found that there were significant differences in hospital profitability between two groups depending upon relevant indices such as labor cost ratio, maintenance expense ratio, number of operations per medical specialist and medical instrument turnover. According to analysis on potential effects of relevant indices upon profitability, it was found that each index had its explanatory power ranging from 25% to 74.5% depending on given model.

• Journal of Environmental Policy
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• v.13 no.4
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• pp.3-49
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• 2014

Growing interest of stakeholders on corporate responsibilities for environment and tightening environmental regulations are highlighting the importance of environmental management more than ever. However, companies' awareness of the importance of environment is still falling behind, and related academic works have not shown consistent conclusions on the relationship between environmental performance and economic performance. One of the reasons is different ways of measuring these two performances. The evaluation scope of economic performance is relatively narrow and the performance can be measured by a unified unit such as price, while the scope of environmental performance is diverse and a wide range of units are used for measuring environmental performances instead of using a single unified unit. Therefore, the results of works can be different depending on the performance indicators selected. In order to resolve this problem, generalized and standardized performance indicators should be developed. In particular, the performance indicators should be able to cover the concepts of both environmental and economic performances because the recent idea of environmental management has expanded to encompass the concept of sustainability. Another reason is that most of the current researches tend to focus on the motive of environmental investments and environmental performance, and do not offer a guideline for an effective implementation strategy for environmental management. For example, a process improvement strategy or a market discrimination strategy can be deployed through comparing the environment competitiveness among the companies in the same or similar industries, so that a virtuous cyclical relationship between environmental and economic performances can be secured. A novel method for measuring eco-efficiency by utilizing Data Envelopment Analysis (DEA), which is able to combine multiple environmental and economic performances, is proposed in this report. Based on the eco-efficiencies, the environmental competitiveness is analyzed and the optimal combination of inputs and outputs are recommended for improving the eco-efficiencies of inefficient firms. Furthermore, the panel analysis is applied to the causal relationship between eco-efficiency and economic performance, and the pooled regression model is used to investigate the relationship between eco-efficiency and economic performance. The four-year eco-efficiencies between 2010 and 2013 of 23 companies are obtained from the DEA analysis; a comparison of efficiencies among 23 companies is carried out in terms of technical efficiency(TE), pure technical efficiency(PTE) and scale efficiency(SE), and then a set of recommendations for optimal combination of inputs and outputs are suggested for the inefficient companies. Furthermore, the experimental results with the panel analysis have demonstrated the causality from eco-efficiency to economic performance. The results of the pooled regression have shown that eco-efficiency positively affect financial perform ances(ROA and ROS) of the companies, as well as firm values(Tobin Q, stock price, and stock returns). This report proposes a novel approach for generating standardized performance indicators obtained from multiple environmental and economic performances, so that it is able to enhance the generality of relevant researches and provide a deep insight into the sustainability of environmental management. Furthermore, using efficiency indicators obtained from the DEA model, the cause of change in eco-efficiency can be investigated and an effective strategy for environmental management can be suggested. Finally, this report can be a motive for environmental management by providing empirical evidence that environmental investments can improve economic performance.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.599-604
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• 2014

This study was conducted to analyze the ecological environment of the 53 uninhabitable islands of Jeju for the management formulation. The result of the Pearson correlation analysis were 0.647(p<0.01) for herbs, 0.585(p<0.01) for trees and 0.762 (p<0.01) for animals which means that there is a high correlation between the size of the forests in the uninhabitable islands and the species diversity of herbs, trees and animals. For the regression modeling to predict the forest area, the R value was 0.899 and the $R^2$ was 0.803 with 79.7% statistical significance. This study also classified the uninhabited islands based on its forest area into two classes, with a forests area of 0.5ha and with a forest of approximately 12ha. The importance value of the biodiversity in the uninhabited islands was also evaluated using DEA and the islands with higher importance, namely DMU14(0.941), DMU36(0.964), DMU44(1.000) and DMU45(0.903) were recommended to be managed. It was observed that uninhabited islands with forests had a mean importance value of 0.439 which is higher as compared to the uninhabited islands without forests with 0.096. This verified that there is close relationship between forest and biodiversity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.29-41
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• 2017

Design rainfalls are one of the most important hydrologic data for river management, hydraulic structure design and risk analysis. The design rainfalls are first estimated by a point frequency analysis and the IDF (intensity-duration-frequency) curve is then constructed by a nonlinear regression to either interpolate or extrapolate the design rainfalls for other durations which are not used in the frequency analysis. It has been widely recognised that the more reliable approaches are required to better account for uncertainties associated with the model parameters under circumstances where limited hydrologic data are available for the watershed of interest. For these reasons, this study developed a hierarchical Bayesian based GLM (generalized linear model) for a regional frequency analysis in conjunction with a scaling function of the parameters in probability distribution. The proposed model provided a reliable estimation of a set of parameters for each individual station, as well as offered a regional estimate of the parameters, which allow us to have a regional IDF curve. Overall, we expected the proposed model can be used for different aspects of water resources planning at various stages and in addition for the ungaged basin.