TY - GEN

T1 - Optimal design of water distribution systems considering uncertainties in demands and roughness coefficients

AU - Jung, Donghwi

AU - Chung, Gunhui

AU - Kim, Joong Hoon

PY - 2012

Y1 - 2012

N2 - The optimal design of water distribution system has been usually performed with fixed hydraulic variables and single objective. However, a realistic water distribution system should take inherent uncertainties of data into consideration. This study suggests a method to minimize the system cost and maximize the robustness of network based on uncertainties in nodal demands and pipe roughness coefficients. Multi-Objective Genetic Algorithm (MOGA) implements two separate optimization models for the least cost and the best robustness design as the initial population. The model considers the uncertainties in roughness coefficient and water demand by using Latin Hypercube sampling techniquewith the assumption of beta probability density function. Several beta probability density functions with wide range of data are evaluated in the procedure. The proposed approach is tested in case study of the New York Tunnels. The parameter for the assessment of pressure variability a is introduced and the critical node is defined as the node having the highest pressure difference when random nodal demands are applied. Robustness is estimated by minimizing the pressure variation at the critical node and the sum of those at all nodes in the system and evaluated using the disturbance index (DI). As a result, the robustness of entire system is decreased or not guaranteed when only critical node is considered to estimate the robustness. Therefore, the entire system's nodes are recommended to be considered when robustness of water distribution system is evaluated to design more reliable networks.

AB - The optimal design of water distribution system has been usually performed with fixed hydraulic variables and single objective. However, a realistic water distribution system should take inherent uncertainties of data into consideration. This study suggests a method to minimize the system cost and maximize the robustness of network based on uncertainties in nodal demands and pipe roughness coefficients. Multi-Objective Genetic Algorithm (MOGA) implements two separate optimization models for the least cost and the best robustness design as the initial population. The model considers the uncertainties in roughness coefficient and water demand by using Latin Hypercube sampling techniquewith the assumption of beta probability density function. Several beta probability density functions with wide range of data are evaluated in the procedure. The proposed approach is tested in case study of the New York Tunnels. The parameter for the assessment of pressure variability a is introduced and the critical node is defined as the node having the highest pressure difference when random nodal demands are applied. Robustness is estimated by minimizing the pressure variation at the critical node and the sum of those at all nodes in the system and evaluated using the disturbance index (DI). As a result, the robustness of entire system is decreased or not guaranteed when only critical node is considered to estimate the robustness. Therefore, the entire system's nodes are recommended to be considered when robustness of water distribution system is evaluated to design more reliable networks.

KW - Multi-objective Genetic Algorithms (MOGA)

KW - Robustness

KW - Uncertainty

KW - Water Distribution System (WDS), Latin hypercube

UR - http://www.scopus.com/inward/record.url?scp=84862958683&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84862958683&partnerID=8YFLogxK

U2 - 10.1061/41203(425)124

DO - 10.1061/41203(425)124

M3 - Conference contribution

AN - SCOPUS:84862958683

SN - 9780784412039

T3 - Water Distribution Systems Analysis 2010 - Proceedings of the 12th International Conference, WDSA 2010

SP - 1390

EP - 1399

BT - Water Distribution Systems Analysis 2010 - Proceedings of the 12th International Conference, WDSA 2010

T2 - 12th Annual International Conference on Water Distribution Systems Analysis 2010, WDSA 2010

Y2 - 12 September 2010 through 15 September 2010

ER -