• Journal of the Korea Safety Management & Science
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• v.2 no.3
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• pp.13-25
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• 2000

This paper reviews and classify fault-tree analysis methods developed since 1960 for system safety and reliability. Fault-tree analysis is a useful analytic tool for the reliability and safety of complex systems. The literature on fault-tree analysis is, for the most part, scattered through conference proceedings and company reports. This paper classify the literature according to system definition, fault-tree construction, qualitative evaluation, quantitative evaluation, and available computer codes for fault-tree analysis.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.873-884
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• 2004

This research provides the solution of defect problem and detection of defect and its causes that happen on software development. For developing a reliable software, a key factor is to find and manage defects that are during software development. Based on defect items analysis, we understand associated relation between defects and design defect opportunity tree. Developing the similar project, we can estimate defect and prepare to solve defect by using defect management opportunity tree.

• Industrial Engineering and Management Systems
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• v.10 no.4
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• pp.272-278
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• 2011

Decision tree as a classification tool is being used successfully in many areas such as medical diagnosis, customer churn prediction, signal detection and so on. The main advantage of decision tree classifiers is their capability to break down a complex structure into a collection of simpler structures, thus providing a solution that is easy to interpret. Since decision tree is a top-down algorithm using a divide and conquer induction process, there is a risk of reaching a local optimal solution. This paper proposes a procedure of optimally determining thresholds of the chosen variables for a decision tree using an adaptive particle swarm optimization (APSO). The proposed algorithm consists of two phases. First, we construct a decision tree and choose the relevant variables. Second, we find the optimum thresholds simultaneously using an APSO for those selected variables. To validate the proposed algorithm, several artificial and real datasets are used. We compare our results with the original CART results and show that the proposed algorithm is promising for improving prediction accuracy.

• Culinary science and hospitality research
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• v.24 no.1
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• pp.130-139
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• 2018

The purpose of this study was to grasp the profitability of coffee franchise companies using ROIC tree, ROA and ROE. As a result, ROA was using assets efficiently, and some companies are in desperate need to improve their management based on past brand recognition, and a new paradigm management strategy is urgently required. In particular, the franchise company's current cost burden is greater than comparable firms. In ROE, the capital was operating efficiently. Since ROIC is very difficult to classify business related and operating related amounts accurately based on financial statement information, there is a limit to accurate ROIC calculation. Therefore, ROIC is estimated to be 7.6~38.29% as of 2016 based on ROIC calculation. In the case of continuous growth companies, investments are made to improve steady sales, but some companies seem to be unable to escape from past paradigm. In order to continue the growth of the company beyond the accounting profit in the future, the ROIC Tree can be used to measure the subdivided management performance and propose efficiency plan.

• Journal of Forest and Environmental Science
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• v.32 no.4
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• pp.392-399
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• 2016

This review paper presents guidelines which stakeholders use in addressing on-farm tree planting configuration, establishment, tending, silvi- cultural management, management of pests and diseases, challenges and opportunities as practiced in the medium to high potential areas of Kenya. The tree planting configurations discussed includes blocks planting (woodlot), boundary, compound planting, home/fruit gardens, trees intercropped or mixed with pasture, trees on riverbanks and roadside. Participatory monitoring and evaluation techniques have been highlighted. The main challenges facing tree planting activities include culture and attitude of local people, land and tree tenure, inadequate technical support, lack of recognition and integration of technical information and indigenous knowledge, capital and labour shortages, lack of appropriate incentives measures, damage by domestic and wild animals, conflict over trees on the boundary and policy and legal issues. This guideline targets forest managers, extension agents, students and other practitioners in policy and day to day decision making processes in Kenya.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.119-130
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• 2012

In this paper, we propose ubiquitous tree management system based on GIS and smart-phone using the object-oriented design modeling to maximize the efficiency of tree management. For this, proposed system is implemented in the form of client/server (C/S). The spot tree management system as the client is based on the mobile(PDA, Smart-Phone), whereas the tree management system based on PC as the server makes use of GIS. Also, Web service method instead of CDMA used in exist studies is used for tree data communication among C/S. And problems of existing studies, that is excessive maintenance costs, accessibility shortage of variety users, connectivity shortage of geographic information system will be settled through the convergence of the proposed system development methods, GIS system, smart devices. Therefore, we verify proposed system by using the systemic unit test and qualitative assessment respectively and prove to be more excellent than the existing system based on the mobile, in terms of systemic effectiveness and extendability.

• Journal of Korean Society for Quality Management
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• v.20 no.1
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• pp.107-117
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• 1992

Conventional fault tree analysis has several problems as the estimations and tolerances of the failure probability values. To overcome these problems, fuzzy concepts with natural language can be applied to conventional fault tree analysis. And, we propose the evaluation method of the imprecision of top/basic events and possibility importances of basic events.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.235-238
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• 2000

This article presents an adaptive decision tree algorithm for dynamically reasoning machine failure cause out of real-time, large-scale machine status database. On the basis of experiment using semiconductor etching machine, it has been verified that our model outperforms previously proposed decision tree models.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.2
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• pp.27-38
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• 2003

This study aimed to provide basic data for future management of roadside trees by analyzing problems associated with plantation and management of roadside trees through categorization of functions and organizational structure, plantation and management, and management regulations and generating improvement opportunities based on the result of a survey on the awareness of government officials who are directly in charge of managing roadside trees in 31 cities & counties within Kyonggi province. The summary of key results of this study is as follows. First, "roadside tree-related function" is still not considered to be independent. About a half of government officials in charge did not majored in this field and they spent only about "2.09hours", in average, in the roadside tree-related function out of 8 working hours per day. Second, regarding problems and improvement opportunities in roadside tree-related function, lack of time was considered to be the biggest problem in overall management of roadside trees. As for improvement opportunities, "increase of dedicated manpower" and "system development" to facilitate efficient processing were suggested. Third, an annual budget for roadside tree-related affairs was merely 92 million won per city/county. A registry for management of roadside trees was kept manually. As for the roles of roadside trees, improvement of landscape and securing of green area itself were valued highly. Fourth, Ginkgo biloba, Zelkova serrata, and Prunus yedoensis were suggested to be the most appropriate species for roadside tree and Platanus occidentalis, Populus albaglandulosa, Populus euramericana, and Robinia pseudo-acacia were mentioned to be the least appropriate species.

• International Journal of Highway Engineering
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• v.16 no.4
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• pp.127-134
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• 2014

PURPOSES : To operate more efficient traffic management system, it is utmost important to detect the change in congestion level on a freeway segment rapidly and reliably. This study aims to develop classification method of congestion change type. METHODS: This research proposes two classification methods to capture the change of the congestion level on freeway segments using the dedicated short range communication (DSRC) data and the vehicle detection system (VDS) data. For developing the classification methods, the decision tree models were employed in which the independent variable is the change in congestion level and the covariates are the DSRC and VDS data collected from the freeway segments in Korea. RESULTS : The comparison results show that the decision tree model with DSRC data are better than the decision tree model with VDS data. Specifically, the decision tree model using DSRC data with better fits show approximately 95% accuracies. CONCLUSIONS : It is expected that the congestion change type classified using the decision tree models could play an important role in future freeway traffic management strategy.