• 상하수도학회지
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• 제18권2호
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• pp.145-154
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• 2004

A long-term sewer rehabilitation project consuming an enormous budget needs to be conducted systematically using an optimization skill. The optimal budgeting and ordering of priority for sewer rehabilitation projects are very important with respect to the effectiveness of investment. In this study, the sewer rehabilitation optimization model using fast-messy genetic algorithm is developed to suggest a schedule for optimal sewer rehabilitation in a subcatchment area by modifying the existing GOOSER$^{(R)}$ model having been developed using simple genetic algorithm. The sewer rehabilitation optimization model using fast-messy genetic algorithm can improve the speed converging to the optimal solution relative to GOOSER$^{(R)}$, suggesting that it is more advantageous to the sewer rehabilitation in a larger-scale subcatchment area than GOOSER.

• 한국물환경학회지
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• 제31권2호
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• pp.196-208
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• 2015

This study analyzed the characteristics of sewer flow and its water quality, and investigated changes in the characteristics in three areas where the sewer rehabilitation projects have been carried out. In S1 area, the patterns of the flow became regular and the range of the fluctuation decreased after the sewer rehabilitation. The flow and its BOD concentration increased. The infiltration/inflow and exfiltration showed clear distinction before and after the sewer rehabilitation in this area. In S2 area, the patterns and the range of the fluctuation of the flow made no differences before and after the sewer rehabilitation. The flow decreased slightly and its BOD concentration increased considerably after the sewer rehabilitation. Big decrement in stormwater inflow but small in exfiltration appeared in this area. In S3 area, the patterns and the range of the fluctuation of the flow made no differences before and after the sewer rehabilitation. The flow decreased slightly and its BOD concentration increased in a small rate in this area.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.660-667
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• 2003

In this study, a Multiple Objective Mixed Integer Programming (MOMIP) Model is developed for sewer rehabilitation planning by considering cost, inflow/infiltration. A sewer rehabilitation planning model is required to decide the economic life of the sewer by considering trade-off between cost and inflow/infiltration. And it is required to find the optimal rehabilitation timing, according to the cost effectiveness of each sewer rehabilitation within the budget. To develop such a model, a multiple objective mixed integer programming model is formulated based on network flow optimization. The network is composed of state nodes and arcs. The state nodes represent the remaining life and the arcs represent the change of the state. The model consider multiple objectives which are cost minimization and minimization of inflow/infiltration. Using the multiple objective optimization, the trade-off between the cost and inflow/infiltration is presented to the planner so that a proper sewer rehabilitation plan can be selected.

• 상하수도학회지
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• 제29권1호
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• pp.123-131
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• 2015

A CCTV inspection method has been widely used to assess sewer condition and performance, but Korea lacks a proper decision support system for prioritizing sewer repair and rehabilitation (R&R). The objective of this paper is to introduce the results that we have developed in the Sewer Condition Assessment and Rehabilitation Decision-making (SCARD) Program using MS-EXCEL. The SCARD-Program is based on a standardized defect score for sewer structural and hydraulic assessment. Priorities are ranked based on risk scores, which are calculated by multiplying the sewer severity scores by the environmental impacts. This program is composed of three parts, which are decision-making for sewer condition and performance assessment, decision-making for sewer R&R priority assessment, and decision-making for optimal budget allocation. The SCARD-Program is useful for decision-makers, as it enables them to assess the sewer condition and to prioritize sewer R&R within the limited annual budget. In the future, this program logic will applied to the GIS-based sewer asset management system in local governments.

• 한국방재학회 논문집
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• 제8권6호
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• pp.7-14
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• 2008

하수관거시스템 개량의 주된 목적은 불명수(Inflow/Infiltration, I/I)를 제거함으로써 그 성능을 향상시키는데 있다. 이때 전체 하수관거시스템 내에서 개개 관거별 I/I 발생량을 정량화할 수 있다면, 전체 하수관거시스템 내에서 소유역별 해당 정보의 추출이 보다 명확해질 수 있다. 그러나 실제 현장에서는 예산 및 시간의 제약 때문에 개개 관거의 I/I 발생 정보의 획득은 거의 불가능하다. 본 연구에서는 하수 관거별 I/I 발생량을 AHP(Analytic Hierarch Process)를 이용하여 정량화하였으며, 산정된 관거별 I/I 발생량을 이용하여 효율적인 하수과거 개량 사업 시행을 위한 개량 우선순위 결정 모형(Rehabiliation Priority Decision Model for sewer system, RPDM)을 개발하였다. 개개 관거별 I/I 발생량 산정 결과에 기반하여 RPDM은 개량이 시행되는 기간 동안 발생하는 I/I 발생량을 최소화하는 소유역별 최적 개량 우선순위(Optimal Rehabilitation Priority, ORP)를 유전자 알고리즘을 이용하여 결정한다. 이때 최적 개량 우선순위에 따른 소유역별 개량 시행 시 발생하는 이익은 개량 기간 동안 하수처리장으로 들어가는 I/I의 하수처리비용(Waste Water Treatment Cost, WWTC)에 대한 절감을 의미한다. 본 연구에서는 개발된 RPDM에 의한 최적 개량 우선순위의 결과는 일반적인 하수관거 개량사업의 우선순위 결정 방법인 점수가중평가법(Numerical Weighting Method, NWM)과 최악의 개량순서에 따른 결과들과 비교되었으며, 개량 기간 동안의 I/I 처리비용이 점수가중평가법에 비하여 22%, 최악의 개량순서에 비하여 40% 감소하는 것으로 나타났다.

• 상하수도학회지
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• 제29권1호
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• pp.97-106
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• 2015

A CCTV inspection method has been widely used to assess sewer condition and performance, but Korea lacks a proper decision support system for prioritizing sewer repair and rehabilitation (R&R). The objective of this paper is to introduce the results that we have developed in the Sewer Condition Assessment and Rehabilitation Decision-making (SCARD) Program using MS-EXCEL. The SCARD-Program is based on a standardized defect score for sewer structural and hydraulic assessment. Priorities are ranked based on risk scores, which are calculated by multiplying the sewer severity scores by the environmental impacts. This program is composed of three parts, which are decision-making for sewer condition and performance assessment, decision-making for sewer R&R priority assessment, and decision-making for optimal budget allocation. The SCARD-Program is useful for decision-makers, as it enables them to assess the sewer condition and to prioritize sewer R&R within the limited annual budget. In the future, this program logic will applied to the GIS-based sewer asset management system in local governments.

• 상하수도학회지
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• 제34권4호
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• pp.289-301
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• 2020

Since sewer rehabilitation program requires long construction period and enormous capital investment, determination of rehabilitation priorities is important with systematic planning considering appropriate evaluation parameters. In this research, we applied PROMETHEE(Preference Ranking Organization METHod for Evaluations) known as very objective and scientific multi-criteria decision-making analysis, using the weights determined by AHP(Analytic Hierarchy Process) for the selected sewer evaluation items to calculate the rehabilitation priorities for each sewer sub-catchment in basin Gusan 1 of Seoul. Preference functions and preference thresholds were estimated for each criterion of ratio of lack of hydraulic capacity of sewers, defect ratio, ratio of sewers with velocity less than its minimum criteria, and density of sewers in the sub-catchment. As a result, it was found that region d had the first priority among four sub-catchments. For each and every sewer located in region d, we could also rank sewers to be rehabilitated urgently.

• 한국수자원학회논문집
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• 제36권4호
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• pp.547-559
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• 2003

본 연구에서는 체계적이고 효율적인 하수관거 정비 계획 수립을 위하여 하수관거의 경제적 가치와 불명수 발생량 및 예산 제약 등을 고려한 최적화 모형을 개발 하였다. 하수관거의 최적 정비 계획 모형은 비용 및 환경오염을 일으키는 불명수 발생 사이의 상관관계를 적절히 판단하여 최적의 경제적 사용연수를 결정하여야 하며, 예산 제약 및 각 하수관거와 배수구역의 비용 대비 효과 등을 고려하여 최적의 정비 시점 및 방법을 결정하여야 한다. 이를 위하여 본 연구에서는 관거의 잔존 수명을 상태 노드로 표현하고, 정비에 따른 잔존 수명의 변화를 아크로 표현한 최소비용 네트워크 흐름 최적화(Network Flow Optimization)모형을 구성하였으며, 이를 기초로 예산 제약 및 하수관거 시스템의 정비 특성을 고려한 제약식을 추가한 다중 목적 혼합 정수계획법(Multiple Objective Mixed Integer Programming, MOMIP)을 수립하였다. 이때 모형의 목적식은 비용 최소화 목적과 함께 불명수 발생량 최소화 목적을 추가하여, 의사결정자에게 비용과 불명수 발생량 사이의 영향 관계를 보여줌으로써 적절한 하수관거 정비 계획을 선택할 수 있도록 하였다.

• 한국수자원학회논문집
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• 제37권3호
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• pp.207-217
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• 2004

국내의 경우 전국적으로 관거의 신설보다는 기존에 매설되어있는 관거의 노후에 따른 개량에 대한 관심이 증대되고 있으나, 그에 따른 연구는 미비한 실정이다. 국내ㆍ외에서는 유전자 알고리즘을 이용하여 개량시기를 결정하는 연구 예가 있으나, 이러한 연구에서 개량시기를 결정하는 요소들이 매우 단순하여 관거의 노후에 따른 복합적인 의사결정이 이루어지지 않고 있다. 본 연구에서는 관거별 통수능력 및 불명수 발생량을 산정하여 배수분구내 토구별 최적 개량 우선순위를 결정하는 한편, 유전자 알고리즘을 이용하여 최적개량비용을 산정하는 최적개량 의사결정 시스템을 개발하였다.

• 상하수도학회지
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• 제23권3호
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• pp.321-329
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• 2009

I/I(Infiltration/Inflow) characteristics should be studied to achieve I/I reduction which is a main object of sewer rehabilitation. However, The scientific and practical studies which are based on actual survey within the country are not thorough going enough. The earlier studies were limited because of a short research period and specific region. Thus, In this study, a formula is deduced by intensive correlation analysis between defective number and I/I volume in sewer pipe. It can be used as preliminary data when the project established for cost-effective pipe rehabilitation. The study shows that the researched region have a faulty point at every 9.3m on average and prove correlation between defective number and I/I volume in sewer pipes. Thus, this study can improve the investigation system and estimate the volume of the pipe rehabilitation, when site investigations for rehabilitation have been conducted.