This research carried out an analysis on input cost and leakage reduction effect by leakage reduction method, focusing on the project for establishing an optimal water pipe network management system in the Taebaek region, which has been executed annually since 2009. Based on the result, optimal cost-benefit analysis models for water distribution network rehabilitation project were developed using DEA(data envelopment analysis) and multiple regression analysis, which have been widely utilized for efficiency analysis in public and other projects. DEA and multiple regression analysis were carried out by applying 4 analytical methods involving different ratios and costs. The result showed that the models involving the analytical methods 2 and 4 were of low significance (which therefore were excluded), and only the models involving the analytical methods 1 and 3 were suitable. From the result it was judged that the leakage management method to be executed with the highest priority for the improvement of revenue water ratio was installation of pressure reduction valve, followed by replacement of water distribution pipe, replacement of water supply pipe, and then leakage detection and repair; and that the execution of leakage management methods in this order would be most economical. In addition, replacement of water meter was also shown to be necessary in case there were a large number of defective water meters.

The introduction of coastal vessel traffic services enables vessels in coastal waters to navigate in safety or to get her position with ease and prevents the vessel from becoming cause of casualties. But it needs relatively huge amount of cost to construct and operate and maintain. Thus we must be checked with economical adequacy of the the proposed coastal vessel traffic services by comparing the cost of the construction, operation and maintenance with the expected benefit made by the expected decrease in marine casualties. In previous paper, a proper cost-benefit analysis model for the Korean practice will be suggested. In this Paper, the proposed the cost-benefit analysis model of coastal vessel traffic services was applied to the Koje coastal waters 20mi1es from the top of Maemul-Do and Yokchi-Do. As the result, we confirmed the propriety of the cost-benefit analysis with the application of the proposed model to Koje waters. Also, it is verified that the introduction of coastal vessel traffic services, as proposed, is adequate and economical. The cost-benefit analysis model proposed in this study could be used to investigate the economic Propriety of new aids to navigation and traffic safety facilities in the future.

이 연구는 연안 VTS의 타당성을 검토하기 위한 비용편익분석모델을 제안한다. 특히 모델의 가장 중요한 요소인 비용과 편익의 항목 및 정량화 방법을 세분한다. 제안한 모델은 연안 VTS를 포함한 대형 해상교통안전시설의 타당성을 분석하고, 그 우선순위를 결정에 활용될 수 있을 것이다.