this paper presents a new bi-objective mathematical model for a permutation flowshop scheduling problem with availability constraint in case of preventive maintenance operations on machines. in this paper, preventive maintenance is flexible and there is not a certain time for the maintenance operation; however, time between two consecutive maintenance operations for each machine should not be g...

In general, microgrids have a high renewable energy abandonment rate and grid construction operation costs. To improve the microgrid utilization rate, economic advantages, environmental safety of power operation, we propose hybrid storage capacity optimization method for wind–solar–diesel grid-connected system, based on an augmented ε- constraint method. First, battery is coupled with seasonal ...

During the epidemic outbreak period, number of infected people increased explosively. In order to effectively contain further spread and treat people, it is necessary make reasonable planning for treatment distribution materials. this paper, a multi-objective mixed-integer programming model integrated design emergency medical material networks developed, in which location points, allocation mat...

The problem of maximal hub covering as a challenging problem in operation research. Transportation programming seeks to find an optimal location of a set of hubs to reach maximum flow in a network. Since the main structure's parameters of the problem such as origin-destination flows, costs and travel time, change periodically in the real world applications, new issues arise in handling it. In t...

In order to select the location of fire stations more scientifically and improve efficiency emergency management in chemical industry parks (CIPs), an improved risk calculation model for hazardous chemicals has been proposed by taking domino effect identification major installations into account. analysis effect, Monte Carlo simulation was used. Then, a established with optimization objectives ...

We introduce a tactical resource allocation model for large aerospace engine system manufacturer aimed at long-term production planning. Our identifies the routings product takes through factory, and which machines should be qualified balanced loading, to reduce lead times. prove some important mathematical properties of that are used develop heuristic providing good initial feasible solution. ...

This paper investigates the following natural greedy procedure for clustering in the bi-criterion setting: iteratively grow a set of centers, in each round adding the center from a candidate set that maximally decreases clustering cost. In the case of k-medians and k-means, the key results are as follows. • When the method considers all data points as candidate centers, then selecting O(k log(1...