• Journal of Korea Water Resources Association
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• v.44 no.11
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• pp.903-913
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• 2011

In this paper important factors in determining improvement priorities for water pipes were categorized into the effects of a pipe failure to entire pipe network and the characteristics of individual pipe. Subsequently, mathematical models that can quantify these factors were developed using the Fuzzy techniques. The effects of a pipe failure to entire pipe network and the characteristics of individual pipe that were estimated byFuzzy techniques were coined as Fuzzy Importance Index and Fuzzy Characteristic Index, respectively. The Fuzzy Characteristic Index was further categorized into Fuzzy Deterioration Index and Fuzzy Difficulty Index. Considerations were given to applying weights to specific factors in the developed model depending on the circumstances of model applications. To provide an example of the methodology an example pipe network, Net3, of the EPANET program was used. The Fuzzy Importance Index (FII) and Fuzzy Deterioration Index (FDI) were calculated for the Net3 network by considering the hydraulic effects of a pipe failure on the entire pipe network and the pipe deterioration as one of the individual pipe characteristics. Subsequently, the improvement priorities of the pipes in the Net3 pipe network were established based on the FII and FDI.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.2
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• pp.155-165
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• 2016

Pipe Deterioration Prediction (PDP) and Pipe Failure Risk Prediction (PFRP) models were developed in an attempt to predict the deterioration and failure risk in water mains using fuzzy technique and the markov process. These two models were used to determine the priority in repair and replacement, by predicting the deterioration degree, deterioration rate, failure possibility and remaining life in a study sample comprising 32 water mains. From an analysis approach based on conservative risk with a medium policy risk, the remaining life for 30 of the 32 water mains was less than 5 years for 2 mains (7%), 5-10 years for 8 (27%), 10-15 years for 7 (23%), 15-20 years for 5 (17%), 20-25 years for 5 (17%), and 25 years or more for 2 (7%).

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.369-378
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• 2024

The aim of this study is to conduct a comparative study on the sustainability of the public pension. While the mainstream view on the sustainability of the public pension presupposes financial sustainability, the original purpose of guaranteeing retirement income has been overlooked. The sustainability of the public pension needs to consider not only financial sustainability, but also various factors such as demographic structure, labor productivity, industrial structure, life cycle of working households, government spending on public pensions, economic growth, and social consensus. With this awareness of the problem, this study conducted a fuzzy set qualitative comparative study in 44 countries, including Korea. As a result of the analysis, it was found that Korea had high financial sustainability for a single year, but relatively low integration related to social consultation and public pension operation, and adequacy such as the degree of guarantee and linkage with other pension systems was also relatively low. The sustainability of the broader public pension should be emphasized not only for financial sustainability, but also for adequacy and integration.