Locating Two Transfer Points on a Network with a Trip Covering Criterion and Mixed Distances

In this paper we consider a set of origin-destination pairs in a mixed model in which a network embedded in the plane represents an alternative high-speed transportation system, and study a trip covering problem which consists on locating two points in the network which maximize the number of covered pairs, that is, the number of pairs which use the network by acceding and exiting through such points. To deal with the absence of convexity of this mixed distance function we propose a decomposition method based on formulating a collection of subproblems and solving each of them via discretization of the solution set.Ministerio de Educación, Ciencia e Innovación MTM2009-14243Ministerio de Economía y Competitividad MTM2012-37048Junta de Andalucía P09-TEP-5022Junta de Andalucía P10-FQM-584

A general approach for the location of transfer points on a network with a trip covering criterion and mixed distances

In this paper we consider a trip covering location model in a mixed planar-network space. An embed- ded network in the plane represents an alternative transportation system in which traveling is fasterthan traveling within the plane. We assume that the demand to be covered is given by a set of origin- destination pairs in the plane, with some traffic between them. An origin-destination pair is covered bytwo facility points on the network (or transfer points), if the travel time from the origin to destinationby using the network through such points is not higher than a given acceptance level related to the traveltime without using the network. The facility location problems studied in this work consist of locatingone or two transfer points on the network such that, under several objective functions, the traffic throughthe network is maximized. Due to the continuous nature of these problems, a general approach is pro- posed for discretizing them. Since the non-convexity of the distance function on cyclic networks alsoimplies the absence of convexity of the mixed distance function, such an approach is based on a decom- position process which leads to a collection of subproblems whose solution set can be found by adaptingthe general strategy to each problem considered.Ministerio de Economía y Competitividad MTM2012-37048Ministerio de Economía y Competitividad MTM2015-67706-PJunta de Andalucía P10-FQM-584

Robust mean absolute deviation problems on networks with linear vertex weights

This article deals with incorporating the mean absolute deviation objective function in several robust single facility location models on networks with dynamic evolution of node weights, which are modeled by means of linear functions of a parameter. Specifically, we have considered two robustness criteria applied to the mean absolute deviation problem: the MinMax criterion, and the MinMax regret criterion. For solving the corresponding optimization problems, exact algorithms have been proposed and their complexities have been also analyzed.Ministerio de Ciencia e Innovación MTM2007-67433-C02-(01,02)Ministerio de Ciencia e Innovación MTM2009-14243Ministerio de Ciencia e Innovación MTM2010-19576-C02-(01,02)Ministerio de Ciencia e Innovación DE2009-0057Junta de Andalucía P09-TEP-5022Junta de Andalucía FQM-584

The variance location problem on a network with continuously distributed demand

Most location problems on networks consider discrete nodal demand. However, for many problems, demands are better represented by continuous functions along the edges, in addition to nodal demands. Several papers consider the optimal location problem of one or more facilities when demands are continuously distributed along the network, and the objective function dealt with is the median one. Nevertheless, in location of public services it is desirable to use an equity criterion. One of the latter is variance of distance distribution which has been studied only for discrete nodal demands. In this paper the variance problem has been generalized to the case where one allows the demand to arise discretely on the nodes as well as continuously along the edges. Properties and behaviour of the objective function are studied. Likewise we present an exact algorithm for solving this problem in a network, which reduces the complexity of the exhaustive procedure.Spanish Research Council (DGICYT

The path-variance problem on tree networks

Extensive facility location models on graphs deal with the location of a special type of subgraphs such as paths, trees or cycles and can be considered as extensions of classical point location models. Variance is one of the measures applied in models in which some equality requirement is imposed. In this paper the problem of locating a minimum variance path in a tree network is addressed, and an O(n2 log n) time algorithm is proposed.Ministerio de Ciencia y Tecnología BFM2000-1052-C02-0

A generalized model of equality measures in network location problems

In this paper, the concept of the ordered weighted averaging operator is applied to define a model which unifies and generalizes several inequality measures. For a location x, the value of the new objective function is the ordered weighted average of the absolute deviations from the average distance from the facilities to the location x. Several kinds of networks are studied: cyclic, tree and path networks and, for each of them, the properties of the objective function are analyzed in order to identify a finite dominating set for optimal locations. Polynomial-time algorithms are proposed for these problems, and the corresponding complexity is discussed.Future and Emerging Technologies Unit (European Commission)Ministerio de Educación y Cienci

Aps Sustainable and Inclusive Social Volunteering: learning by doing a service stop the community (II)

El objetivo principal es consolidar el desarrollo de competencias genéricas y específicas que capacite a los y las participantes para transmitir la importancia de la Agenda 2030 en la universidad y la comunidad, desarrollando capacidades de reafirmación social para canalizar acciones encaminadas hacia los Objetivos de Desarrollo Sostenible (ODS). A través de la metodología del Aprendizaje-Servicio se busca promover un encuentro para el trabajo conjunto, mediante la conexión entre la individualidad de las personas, el trabajo grupal y comunitario. Los fundamentos del Trabajo Social nos permitirán trabajar un enfoque de derechos, valores y compromiso. Además, se promoverá el desarrollo de habilidades para la vida desde la educación popular, la educación eco-social, el diseño universal del aprendizaje, los entornos inclusivos, la lectura fácil y los huertos eco-didácticos. En el proyecto participará un grupo de veinte voluntarios/as (estudiantes de grado y máster de la Facultad de Trabajo Social y personas externas con diversidad intelectual), puntualmente estudiantes de Bellas Artes y Estudios Estadísticos. Como Aprendizaje, las actividades formativas programadas buscan formar al voluntariado tanto en los ODS como en las capacidades comentadas anteriormente. Para su desarrollo, se contará con recursos de las entidades colaboradoras, tanto propias de la UCM como externas. Como Servicio a la Comunidad, se propondrá al voluntariado el reto de ser embajadores/as de los ODS, compartiendo su mensaje en la universidad y comunidad, desde el conocimiento científico y el reconocimiento a los demás (cultura, saberes y procesos distintos a los nuestros). La gestión operativa se realizará a tres niveles: equipo técnico, para el seguimiento y evaluación del proyecto; equipo de acompañamiento, para coordinar actividades con el voluntariado y garantizar cohesión grupal; y equipo de relaciones institucionales, para coordinar con entidades colaboradoras los espacios y agenda para las actividades con el voluntariado.The main objective is to consolidate the development of generic and specific skills that train the participants to convey the importance of the 2030 Agenda in the university and the community, developing capacities for social reaffirmation to channel actions aimed at the Sustainable Development Goals ( ODS). Through the Service-Learning methodology, it seeks to promote a meeting for joint work, through the connection between the individuality of people, group and community work. The foundations of Social Work will allow us to work on a focus on rights, values ​​and commitment. In addition, the development of life skills will be promoted from popular education, eco-social education, universal learning design, inclusive environments, easy reading and eco-didactic gardens. A group of twenty volunteers will participate in the project (undergraduate and master's students from the Faculty of Social Work and external people with intellectual diversity), occasionally students of Fine Arts and Statistical Studies. As Learning, the programmed training activities seek to train volunteers both in the SDGs and in the capacities mentioned above. For its development, there will be resources from collaborating entities, both from the UCM and from outside. As Community Service, the challenge of being ambassadors of the SDGs will be proposed to volunteers, sharing their message in the university and community, based on scientific knowledge and recognition of others (culture, knowledge and processes different from ours). Operational management will be carried out at three levels: technical team, for the monitoring and evaluation of the project; support team, to coordinate activities with volunteers and guarantee group cohesion; and institutional relations team, to coordinate with collaborating entities the spaces and agenda for volunteer activities.Depto. de Trabajo Social y Servicios SocialesFac. de Trabajo SocialTRUEServicio ApS. Universidad Complutense de Madridunpu