This paper presents a two-stage optimization method for reliability-based topology optimization (RBTO) of double layer grids that considers uncertainties in applied loads. The optimization is performed using a two-stage optimization by employing the method of moving asymptotes (MMA) and ant colony optimization (ACO), which is called MMA-ACO method. For implementation of MMA-ACO, the structural stiffness is maximized using MMA, first. Then, the results of MMA are used to enhance ACO through the following four modifications: (I) finding the structural importance rate of elements or joints and using this to achieve a better topology, (II) determining the number of compressive and tensile element types, (III) changing the lower limit of available cross-sectional areas for the elements of each group and (IV) modifying the generation of random stable structures. In reliability analysis, multiple criteria i.e. stiffness and eigenvalue are considered where the probability of failure in each mode is calculated by Monte Carlo simulation (MCS). To reduce the computational time, the eigenvalues are evaluated using the third order approximation (TOA). Through numerical examples, reliability-based topology designs of typical double layer grids are obtained by ACO and MMA-ACO methods. The numerical results reveal the computational advantages and effectiveness of the proposed MMA-ACO method for the RBTO of double layer grids. Also, the importance of considering uncertainties is then demonstrated by comparing the results obtained by those of other failure probabilities.

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Although malaria is endemic in some areas of southeastern Iran, following the successful national malaria elimination plan, the local transmission area has been shrunk. The main cases in Iran are due to Plasmodium vivax followed by P. falciparum. This study was aimed to determine the current situation of malaria in Kerman Province of Iran and evaluate the insecticide resistance of main vectors. The field study was conducted in 2019. Data of new malaria cases were obtained from the health centers for the period of 2009–2018. Susceptibility status of Anopheles stephensi and An. dthali was evaluated against dichlorodiphenyltrichloroethane, Dieldrin, Malathion, Bendiocarb, Deltamethrin, and Temephos at the diagnostic dose. A total of 522 malaria cases were recorded and divided into indigenous (33.14%) and imported (66.86%) categories. The highest incidence of the disease was reported from the southern areas of the province, where all indigenous cases occurred. Adults of An. stephensi were resistant to dichlorodiphenyltrichloroethane while its resistance to be confirmed to dieldrin, bendiocarb and deltamethrin. As An. dthali had less than 98% mortality against bendiocarb, the resistance status should be confirmed with more tests. Our findings showed both species had less than 98% mortality against bendiocarb and deltamethrin insecticides which are used in malaria vector control program in Iran. Due to the susceptibility of these vectors to temephos, larviciding can be advised for vector control in this area.