A mathematical model and application on the prevention of gerrymandering

The significance of the political districting also known as redistricting has been recognized by several countries across the world since electoral district boundaries can be manipulated for a political gain. This manipulation practice is known as gerrymandering and has serious influences on the results of an election. In this thesis, we tried to show how easy policymakers can misuse the redistricting practice to gain a political advantage such as increasing the number of their representatives in the parliament. Two different mathematical models have been developed for different types of election systems. Single-member district electoral system in which the only representative can be elected from each electoral district is one of them. Every county in ˙Istanbul has been tried to be divided into their single-member districts considering the total number of representatives of the county. In addition to the first model, another formulation has been developed to also cover the multi-member district systems. The main drawback of the mathematical models is that they are only working on the small cases in terms of the total number of political units. Tabu search algorithm has been developed to answer the cases that cannot be classified as small. The required algorithm steps such as initialization, neighborhood change structure etc. are explained in detail. The results of the mathematical models and the algorithm have been achieved and visualized aesthetically

Estado del arte en procesos de zonificacion

Los procesos de partición espacial implican la división de un espacio geográfico en diferentes unidades o zonas según un conjunto específico de criterios. En ámbitos relacionados con las ciencias geoespaciales, la delimitación de estas zonas se realiza por agrupación de otras unidades básicas de área existentes en el espacio de trabajo. En este artículo se ofrece una revisión de los métodos de solución diseñados para este tipo de problemas, comenzando por una introducción a las técnicas heurísticas y modelos matemáticos más utilizados desde los años 60, para finalizar describiendo los recientes algoritmos aplicados a diagramas de Voronoi. También se revisan las aplicaciones en las que se han implementado algunos de estos modelos, quedando patente que son herramientas diseñadas para el tratamiento de problemas específicos, dada la dificultad de diseñar modelos genéricos y versátiles para este tipo de particiones espaciales o zonificacione

Operational research IO 2021—analytics for a better world. XXI Congress of APDIO, Figueira da Foz, Portugal, November 7–8, 2021

This book provides the current status of research on the application of OR methods to solve emerging and relevant operations management problems. Each chapter is a selected contribution of the IO2021 - XXI Congress of APDIO, the Portuguese Association of Operational Research, held in Figueira da Foz from 7 to 8 November 2021. Under the theme of analytics for a better world, the book presents interesting results and applications of OR cutting-edge methods and techniques to various real-world problems. Of particular importance are works applying nonlinear, multi-objective optimization, hybrid heuristics, multicriteria decision analysis, data envelopment analysis, simulation, clustering techniques and decision support systems, in different areas such as supply chain management, production planning and scheduling, logistics, energy, telecommunications, finance and health. All chapters were carefully reviewed by the members of the scientific program committee.info:eu-repo/semantics/publishedVersio

Models, algorithms, and heuristics for multiobjective commercial territory design

In general, distribution firms have complex product distribution networks which are formed by thousands of sales points. In this kind of industry there are many interesting problems from the logistic point of view that can appear in different stages of the decision process. For instance, when a firm is starting, a first problem could be the facility location: where to install the warehouses and/or distribution centers. After that, in order to provide efficient service and to reduce total costs (i.e., production, stock and distribution costs) some questions such as how many products need to be produced, and how to deliver the products to the final customer, need to be answered

Location models in the public sector

The past four decades have witnessed an explosive growth in the field of networkbased facility location modeling. This is not at all surprising since location policy is one of the most profitable areas of applied systems analysis in regional science and ample theoretical and applied challenges are offered. Location-allocation models seek the location of facilities and/or services (e.g., schools, hospitals, and warehouses) so as to optimize one or several objectives generally related to the efficiency of the system or to the allocation of resources. This paper concerns the location of facilities or services in discrete space or networks, that are related to the public sector, such as emergency services (ambulances, fire stations, and police units), school systems and postal facilities. The paper is structured as follows: first, we will focus on public facility location models that use some type of coverage criterion, with special emphasis in emergency services. The second section will examine models based on the P-Median problem and some of the issues faced by planners when implementing this formulation in real world locational decisions. Finally, the last section will examine new trends in public sector facility location modeling.Location analysis, public facilities, covering models