博士 / 國立中央大學 / 環境工程研究所 / 94 / The optimal design of new sewer systems becomes an important issue for the necessary of cost-effectiveness analysis. However the result of traditional design approach is only a very small number of the alternatives can be evaluated; therefore the final design is sometimes deficient and there is no guarantee that it is the best design. This has more inspired the research on computerized optimization models for sewer systems planning and design. In this study, according to the design procedure of experience engineer, the practical Optimization Models for Sewer Systems Planning and Design are developed with system analysis approach and divided into two phases: (1) at first, an urban Sewer System Optimization Model (SSOM) for hydraulic design is established and has become a general module for being applied to hydraulic design, which can be employed to determine the size and slope of the sewer pipes for a “fixed layout” sewer system design problem. The SSOM model uses a 0-1 mixed integer programming (MIP) and an efficient screening algorithm, the bounded implicit enumeration (BIE) algorithm. The particular consideration is to provide a set of design variables for urban sewer system design problems corresponding to the various construction modes; and (2) then the Sewer System Optimization Model for Layout & Hydraulic design
(SSOM/LH) is established to find the optimal “system layout” for an “unfixed layout” sewer system. The goal of the optimal system layout process is to arrange a network of sewer pipes for collecting and transporting the wastewater considering the populations, the discharge flow-rate, street layout and topography of the area. Thus, the SSOM/LH was constructed as a combinatorial model to combine the Total Enumeration (TE) algorithm for a “network layout” generating procedure with the general module of developed SSOM for an optimal hydraulic design procedure. Both of the procedures perform a screening role to achieve the optimization of the “network layout” and “hydraulic design” simultaneously, and ensuring ensure that the solution obtained is globally optimal. However, in the search for optimality, the number of feasible network layout combinations increases exponentially as the number of manholes increases. This would predictably lead to an N-P complete problem if a huge sewer system is planned. To remedy the flaws in SSOM/LH, a genetic algorithm (GA) will be applied to reestablish this optimization model namely GA/SSOM/LH. “one system layout parameter in the GA evolutionary process is coded to represent one chromosome”. The specific coding strings for the “parameters” are then operated directly, resulting in a more efficient search for the optimal sewer system layout and ensuring a solution closer to the global optimum in a ‘fast’ manner. The optimality of GA/SSLOM obtained could possibly be in a local optimum.
In this study, a concept of hybrid algorithm is first applied to establish a Two-Hybrid Sewer System Layout Optimization Model (2-Hybrid SSLOM) involving this couple of developed model’s advantages in a hybrid role for the minimum cost objective. Finally, several of case studies are conducted to verify that this developed 2-Hybrid SSLOM can indeed search for the global optimum solution with the more increased efficiency than SSOM/LH and develop as a future sewer system planning model for the convenience of solving more complicated pipeline system optimization problems.
| Identifer | oai:union.ndltd.org:TW/094NCU05515038 |
| Date | January 2006 |
| Creators | Huahn-Tyng Weng, 翁煥廷 |
| Contributors | Shu-Liang Liaw, 廖述良 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 148 |
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