110 research outputs found

    Internet of Things in urban waste collection

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    Nowadays, the waste collection management has an important role in urban areas. This paper faces this issue and proposes the application of a metaheuristic for the optimization of a weekly schedule and routing of the waste collection activities in an urban area. Differently to several contributions in literature, fixed periodic routes are not imposed. The results significantly improve the performance of the company involved, both in terms of resources used and costs saving

    Benchmarking Optimization Algorithms for Capacitated Vehicle Routing Problems

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    The Vehicle Routing Problem (VRP) originated in the 1950s when algorithms and mathematical approaches were applied to find solutions for routing vehicles. Since then, there has been extensive research in the field of VRPs to solve real-life problems. The process of generating an optimal routing schedule for a VRP is complex due to two reasons. First, VRP is considered to be an NP-Hard problem. Second, there are several constraints involved, such as the number of available vehicles, the vehicle capacities, time-windows for pickup or delivery etc. The main goal for this project was to compare different optimization algorithms for solving Capacitated Vehicle Routing Problems (CVRP). The three specific aims for this project were to (1) survey existing research and identify suitable optimization algorithms for CVRP and (2) implement a work-flow in the Python programming lan- guage, to evaluate their performance, (3) perform different computational experiments on existing CVRP benchmarks. Experiments were conducted by leveraging Google’s OR-Tools library on the well-known benchmarks. Different strategies were evaluated to see if there exists a solution or a better solution than the best-known solutions for these benchmarks. The results show that almost 60% of the problems in the benchmarks have a better solution than the current best-known solution. The second finding of this project is that there is not one strategy which can provide the best solution for all types of CVRPs

    An MINLP model to support the movement and storage decisions of the Indian food grain supply chain

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    This paper addresses the novel three stage food grain distribution problem of Public Distribution System (PDS) in India which comprises of farmers, procurement centers, base silos and field silos. The Indian food grain supply chain consists of various activities such as procurement, storage, transportation and distribution of food grain. In order to curb transportation and storage losses of food grain, the Food Corporation of India (FCI) is moving towards the modernized bulk food grain supply chain system. This paper develops a Mixed Integer Non-Linear Programming (MINLP) model for planning the movement and storage of food grain from surplus states to deficit states considering the seasonal procurement, silo capacity, demand satisfaction and vehicle capacity constraints. The objective function of the model seeks to minimize the bulk food grain transportation, inventory holding, and operational cost. Therein, shipment cost contains the fixed and variable cost, inventory holding and operational cost considered at the procurement centers and base silos. The developed mathematical model is computationally complex in nature due to nonlinearity, the presence of numerous binary and integer variables along with a huge number of constraints, thus, it is very difficult to solve it using exact methods. Therefore, recently developed, Hybrid Particle-Chemical Reaction Optimization (HP-CRO) algorithm has been employed to solve the MINLP model. Different problem instances with growing complexities are solved using HP-CRO and the results are compared with basic Chemical Reaction Optimization (CRO) and Particle Swarm Optimization (PSO) algorithms. The results of computational experiments illustrate that the HP-CRO algorithm is competent enough to obtain the better quality solutions within reasonable computational time
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