Person: Tejada Cazorla, Juan Antonio
Universidad Complutense de Madrid
Faculty / Institute
Estadística e Investigación Operativa
Estadística e Investigación Operativa
Now showing 1 - 10 of 42
PublicationHarmonic manifolds and embedded surfaces arising from a super regular tesselation(World Scientific PublCo, 2017) Brumfiel, G.; Hilde, H.; Lozano, M. T.; Montesinos Amilibia, José María; Ramirez, E.; Short, H.; Tejada Cazorla, Juan Antonio; Toro, M.The main result of this paper is the construction of two Hyperbolic manifolds, M-1 and M-2, with several remarkable properties: (1) Every closed orientable 3-manifold is homeomorphic to the quotient space of the action of a group of order 16 on some covering space of M-1 or M-2. (2) M1 and M2 are tesselated by 16 dodecahedra such that the pentagonal faces of the dodecahedra fit together in a certain way. (3) There are 12 closed non-orientable hyperbolic surfaces of Euler characteristic -2 each of which is tesselated by regular right angled pentagons and embedded in M1 or M2. The union of the pentagonal faces of the tesselating dodecahedra equals the union of the 12 images of the embedded surfaces of Euler characteristic -2. PublicationPreface to the special issue on the occasion of the 3rd Spain–Italy–Netherlands Meeting on Game Theory (SING 3)(Sociedad de Estadística e Investigación Operativa, 2009) Norde, Henk; Patrone, Fioravante; Tejada Cazorla, Juan Antonio PublicationThe position value as a centrality measure in social networks(2023) Lopez, Susana; Molina Ferragut, Elisenda; Saboyá, Martha; Tejada Cazorla, Juan AntonioThe position value, introduced by Meessen (1988), is a solution concept for cooperative games in which the value assigned to a player depends on the value of the connections or links he has with other players. This concept has been studied by Borm et al. (1992) and characterised by Slikker (2005). In this paper, we analyse the position value from the point of view of the typical properties of a measure of centrality in a social network. We extend the analysis already developed in Gomez et al. (2003) for the Myerson centrality measure, where the symmetric effect on the centralities of the end nodes of an added or removed edge is a fundamental part of its characterisation. However, the Position centrality measure, unlike the Myerson centrality measure, responds in a more versatile way to such addition or elimination. After studying the aforementioned properties, we will focus on the analysis and characterisation of the Position attachment centrality given by the position value when the underlying game is the attachment game. Some comparisons are made with the attachment centrality introduced by Skibski et al. (2019). PublicationFuzzy preferences in knowledge-based systems(World Scientific, 1995) Montero, Javier; Tejada Cazorla, Juan Antonio; Cutello, V.; Cooman, Gert de; Ruan, Da; Kerre, Etienne E.This paper deals with fuzzy preferences. Many different alternative definitions of strict and weak fuzzy preferences can be found in the literature. But most of them do not take into account that fuzzy preferences should allow a complete preference structure, where not only strict and weak preferences are defined, but also indifference and incomparability. The whole preference structure should be built in order to be properly considered as a basis for knowledge based systems. Taking into account a previous work of Montero, we introduce some modifications in the model recently developed by Fodor, Ovchinnikov and Roubens in such a way that consistent fuzzy preference structures are fully characterized. PublicationMultivalued continuum systems(Elsevier Science, 1993-08-27) Montero, Javier; Tejada Cazorla, Juan Antonio; Yáñez, JavierThis paper deals with continuum systems, where a continuous degree of performance levels between perfect functioning and complete failure is allowed. Here we shall assume that the system can be modeled as a structure function given by a mapping from the n-dimensional unit hypercube into a k-dimensional unit hypercube, in such a way that the performance of the system is described according to k single continuum-valued criteria. Some basic concepts relative to these continuum multivalued systems are discussed and general reliability bounds are obtained based upon the minimal paths and minimal cuts of the k associated single-valued continuum systems. PublicationSplitting graphs when calculating Myerson value for pure overhead games(Springer, 2004-07) González-Arangüena, Enrique; Manuel García, Conrado Miguel; Owen, Guillermo; Pozo, M. del; Tejada Cazorla, Juan AntonioA communication situation consists of a coalitional game and a graph, the nodes of the graph corresponding to the players of the game. To calculate the Myerson value for such situations, we obtain results which extend those well known for trees and cycle-complete graphs. On the other hand, in order to reduce the associated calculus for communication situations with a pure overhead game, the possibility of splitting the graph in several subgraphs is analyzed. For each fixed decomposition of the graph, a subspace of games compatible with this decomposition is given. PublicationMixed mechanisms for auctioning ranked items(MDPI, 2020-12-15) Alonso, Estrella; Sánchez-Soriano, Joaquín; Tejada Cazorla, Juan AntonioThis paper deals with the problem of designing and choosing auctioning mechanisms for multiple commonly ranked objects as, for instance, keyword auctions in search engines on Internet. We shall adopt the point of view of the auctioneer who has to select the auction mechanism to be implemented not only considering its expected revenue, but also its associated risk. In order to do this, we consider a wide parametric family of auction mechanisms which contains the generalizations of discriminatory-price auction, uniform-price auction and Vickrey auction. For completeness, we also analyze the Generalized Second Price (GSP) auction which is not in the family. The main results are: (1) all members of the family satisfy the four basic properties of fairness, no over-payment, optimality and efficiency, (2) the Bayesian Nash equilibrium and the corresponding value at risk for the auctioneer are obtained for the considered auctions, (3) the GSP and all auctions in the family provide the same expected revenue, (4) there are new interesting auction mechanisms in the family which have a lower value at risk than the GSP and the classical auctions. Therefore, a window opens to apply new auction mechanisms that can reduce the risk to be assumed by auctioneers. PublicationAllocating slacks in stochastic PERT network(Springer, 2014-03) Castro Cantalejo, Javier; Gómez González, Daniel; Tejada Cazorla, Juan AntonioThe SPERT problem was defined, in a game theory framework, as the fair allocation of the slack or float among the activities in a PERT network previous to the execution of the project. Previous approaches tackle with this problem imposing that the durations of the activities are deterministic. In this paper, we extend the SPERT problem into a stochastic framework defining a new solution that tries also to maintain the good performance of some other approaches that have been defined for the deterministic case. Afterward, we present a polynomial algorithm for this new solution that also could be used for the calculation of other approaches founded in the deterministic SPERT literature.