Carmela Piccolo

Equality measures properties for location problems

The objectives underlying location decisions can be various. Among them, equity objectives have received an increasing attention in recent years, especially in the applications related to the public sector, where fair distributions of accessibility to the services should be guaranteed among users. In the literature a huge number of equality measures have been proposed; then, the problem of selecting the most appropriate one to be adopted in the decision-making processes is crucial. For this reason, many authors focused on the analysis of properties that equality measures should satisfy in order to be considered suitable. Most of the proposed properties are too general and related solely to the mathematical formulation of the measure itself (i.e., simpleness, impartiality, invariance). Hence, they do not give any indications about the behaviour of such measures in the optimization contexts. In this work, we propose some new properties to be associated to equality measures in order to describe characteristics which may be useful to drive optimization procedures in the search of optimal (or near-optimal) solutions. To this aim some empirical analyses have been performed in order to understand the typical behavior of remarkable measures in presence of a uniform distribution of demand points in a regular location spaces.

Capacity management in public service facility networks: a model, computational tests and a case study

In this work, we present a mathematical model to support location decisions oriented to rationalize facility systems in non-competitive contexts. In order to test the model, computational results are shown and an application to a real-world case study, concerning the Higher Education system in an Italian region, is discussed.

A unified solving approach for two and three dimensional coverage problems in sensor networks

The problem of designing a wired or a wireless sensor network to cover, monitor and/or control a region of interest has been widely treated in literature. This problem is referred to in literature as the sensor placement problem (SPP) and in the most general case it consists in determining the number and the location of one or more kind of sensors with the aim of covering all the region of interest or a significant part of it. In this paper we propose a unified and stepwise solving approach for two and three dimensional coverage problems to be used in omni-directional and directional sensor networks. The proposed approach is based on schematizing the region of interest and the sensor potential locations by a grid of points and representing the sensor coverage area by a circle or by a circular sector. On this basis, the SPP is reduced to an optimal coverage problem and can be formulated by integer linear programming (ILP) models. We will resume the main ILP models used in our approach, highlighting, for each of them, the specific target to be achieved and the design constraints taken into account. The paper concludes with an application of the proposed approach to a real test case and a discussion of the obtained results.

A Districting Model to Support the Redesign Process of Italian Provinces

In the general context of welfare reforms in western economies, many actions concerning the rationalization of local administrative structures have been undertaken. In particular, in Italy a recent debate has been addressed about the reduction of the overall number of provinces and the rearrangement of their borders. As provinces are responsible of providing some essential services to the population within their boundaries, any possible scenario should combine the need for more efficient territorial configurations with the safeguard of the services’ accessibility. From a methodological point of view, such problem involves aspects from both facility location and districting problems. In this work, we formulate a mathematical model to support the decision making process and we compare scenarios provided on four benchmark problems, built on the real data associated to the most representative Italian regions.

An Optimization Model for the Outbound Truck Scheduling Problem at Cross-Docking Platforms

A cross-dock is a facility where arriving materials are sorted, grouped and delivered to destinations, with very limited storage times, with the overall objective of optimizing the total management costs. The operational efficiency of a cross-docking system strongly depends on how the logistic activities are organized. For this reason, optimization models and methods can be very useful to improve the system performances. In this paper, we propose a mathematical model to describe the so-called truck scheduling problem at a cross-docking platform. The model considers most of the actual constraints occurring in real problems; therefore, it can be viewed as an interesting basis to define a decision support system for this kind of problems. Some preliminary results show that the model can be efficiently solved in limited computational times.