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A comparison between optimization tools to solve sectorization problem
Teymourifar, Aydin; Rodrigues, Ana Maria; Ferreira, José Soeiro; Lopes, CristinaIn sectorization problems, a large district is split into small ones, usually meeting certain criteria. In this study, at first, two single-objective integer programming models for sectorization are presented. Models contain sector centers and customers, which are known beforehand. Sectors are established by assigning a subset of customers to each center, regarding objective functions like equilibrium and compa...
A new model and solution method for the dynamic sectorization problem
Teymourifar, Aydin; Rodrigues, Ana Maria; Ferreira, José SoeiroIn sectorization problems (SPs), a large area is divided into smaller regions for administrative purposes. SPs have applications in many fields. Since real-life problems are often dynamic, in this study, a new model for dynamic SP is proposed. In the problem, points are assigned to service centres and in this way sectors are formed. The sectors must be balanced in terms of distance and demand, which is defined ...
A new model for location-allocation problem based on sectorization
Teymourifar, Aydin; Rodrigues, Ana Maria; Ferreira, José SoeiroMany models have been proposed for the location-allocation problem. In this study, based on sectorization concept, we propose a new single-objective model of this problem, in which, there is a set of customers to be assigned to distribution centres (DCs). In sectorization problems there are two important criteria as compactness and equilibrium, which can be defined as constraints as well as objective functions....
A Monte Carlo simulation-based approach to solve dynamic sectorization problem
Teymourifar, Aydin; Rodrigues, Ana Maria; Ferreira, José SoeiroIn this study, two novel stochastic models are introduced to solve the dynamic sectorization problem, in which sectors are created by assigning points to service centres. The objective function of the first model is defined based on the equilibration of the distance in the sectors, while in the second one, it is based on the equilibration of the demands of the sectors. Both models impose constraints on assignme...
A comparison between metaheuristic-based and solver-based methods to solve rout...
Teymourifar, Aydin; Rodrigues, Ana Maria; Ferreira, José SoeiroThis study involves the division of a region into smaller units, based on sectorization, and a route determination for each of them. The routing problem of each unit is defined as a basic traveling salesman problem (TSP). Different implementations of a widely used method to solve TSP are compared. The method is based on a mixed-integer linear programming model, in which after finding an initial solution, a sub-...
Shannon’s entropy method to find weights of objectives in sectorization problem
Teymourifar, Aydin; Rodrigues, Ana Maria; Ferreira, José SoeiroOne of the most widely used methods in multi-objective optimization problems is the weighted sum method. However, in this method, defining the weights of objectives is always a challenge. Various methods have been suggested to achieve the weights, one of which is Shannon’s entropy method. In this study, a bi-objective model is introduced to solve the sectorization problem. As a solution method, the model is tra...
Integrated resolution of assignment, sequencing and cutting problems in paper p...
Correia, Maria Helena; Oliveira, José Fernando; Ferreira, José SoeiroThe integrated planning of several activities implicated in paper production can lead to remarkable gains in terms of raw materials and resource usage. However, activities such as order assignment, production sequencing and cutting planning are usually addressed separately while ignoring the interactions among these processes. But the quality of the solution resulting from the juxtaposition of the partial solut...