Comparison of algorithms for the optimal location of control valves for leakage reduction in WDNs

The paper presents the comparison of two different algorithms for the optimal location of control valves for leakage reduction in water distribution networks (WDNs). The former is based on the sequential addition (SA) of control valves. At the generic step Nval of SA, the search for the optimal combination of Nval valves is carried out, while containing the optimal combination of Nval − 1 valves found at the previous step. Therefore, only one new valve location is searched for at each step of SA, among all the remaining available locations. The latter algorithm consists of a multi-objective genetic algorithm (GA), in which valve locations are encoded inside individual genes. For the sake of consistency, the same embedded algorithm, based on iterated linear programming (LP), was used inside SA and GA, to search for the optimal valve settings at various time slots in the day. The results of applications to two WDNs show that SA and GA yield identical results for small values of Nval. When this number grows, the limitations of SA, related to its reduced exploration of the research space, emerge. In fact, for higher values of Nval, SA tends to produce less beneficial valve locations in terms of leakage abatement. However, the smaller computation time of SA may make this algorithm preferable in the case of large WDNs, for which the application of GA would be overly burdensome.Enrico Creaco, Giuseppe Pezzing

Design and optimization of healthcare location-inventory problem in the relief supply chains

Given the increase of natural disasters, the community's need for health services has increased dramatically. Firstly, the condition of the injured people should be determined and then the treatment should be start, and in the event of increasing in the severity of the injured, these people should be transfer to the hospitals in the shortest possible time. On the other hand, another essential measure at the time of the accident is to send medicines and medical items at the appropriate time for treatment of injured. In this regard, we follow to design an emergency relief supply chain network including suppliers of medical items, treatment center, warehouses, and disaster points. Therefore, a location and inventory mathematical modeling is proposed to provide better services with the goal of minimizing the costs associated with locating and inventory of health systems. Thenو, to analyze and optimize the problem, proposed some numerical example and genetic algorithm