Suchergebnisse

Following the original interpretation of the Shapley value (Shapley, 1953a) as a priori evaluation of the prospects of a player in a multi-person iteraction situation, we propose a group value, which we call the Shapley group value, as a priori evaluation of the prospects of a group of players in a coalitional game when acting as a unit. We study its properties and we give an axiomatic characterization. We motivate our proposal by means of some relevant applications of the Shapley group value, when it is used as an objective function by a decision maker who is trying to identify an optimal group of agents in a framework in which agents interact and the attained benefit can be modeled by means of a transferable utility game. As an illustrative example we analyze the problem of identifying the set of key agents in a terrorist network. ; This research has been supported by I+D+i research project MTM2011-27892 from the Government of Spain

We propose a new type of values for cooperative TU-games, which we call pyramidal values. Assuming that the grand coalition is sequentially formed, and all orderings are equally likely, we define a pyramidal value to be any expected payoff in which the entrant player receives a salary and the right to get part of the benefits derived from subsequent incorporations to the just formed coalition, whereas the remaining benefit is distributed among the incumbent players. To be specific, we consider some parametric families of pyramidal values: the egalitarian pyramidal family, which coincides with the a-consensus value family introduced by Ju et al. in (2007), the proportional pyramidal family, and the weighted pyramidal family, which in turn includes the other two families as special cases. We also analyze the properties of these families, as well as their relationships with other previously defined values. ; This research has been supported by I+D+i research project MTM2011-27892 from the Government of Spain.

Editorial ; Aguilera, Oscar ; Presentación ; Velázquez, Nelly; Romero, Liccia ; La importancia de los cultivos andinos. ; The importance of andean crops. ; Jacobsen, Sven Erik; Mujica, Ángel; Ortiz, Rene ; Colombia: Ambiente, pobreza, violencia. ; Colombia: Environment, poverty and violence. ; Márquez, Germán ; Ambiente, sociedad e historia en los valles altos andinos de Venezuela (1930-1999). ; Environment, society and history in the high valleys of the Venezuelan andes (1930-1999). ; Velázquez, Nelly ; Hacia una nueva racionalidad socioambiental en los Andes paperos de Mérida ¿De qué depende?. ; Towards a new socio-environmental rationality in the potato-producing areas of the Andes in Mérida. What does it depend on?. ; Romero, Liccia ; Modernidad, medio ambiente y equidad. Una propuesta para su estudio en los valles altos de los Andes Venezolanos. ; Modernity, environment and equity: A proposal for study in the high-mountain valleys of the Venezuelan. ; Peñalver, Luz ; Factibilidad de caza de subsistencia, comercial y deportiva en el Chaco semiárido de la provincia de Salta, Argentina. ; Viability of commercial and sporting subsistence hunting in the semiarid Chaco-Salta province, Argentina. ; Barbarán, Francisco Ramón ; Globalización y agricultura: ¿Nuevos tiempos para América Latina?. ; Globalization and agriculture: Better times for Latin America? ; González, Gustavo ; Legislación de aguas en Bolivia. Encontrando bases comunes. ; Water legislation in Bolivia. In search of a common basis. ; Alurralde Tejada, Juan Carlos; Salón, Pablo; Orellana, Rene ; "Del frailejón a la papa. entre la conservación y la agricultura" Maximina Monasterio. ; Una apuesta permanente por el reencuentro entre ecología y sociedad en el escenario de los páramos andinos. ; Entrevista: Lic. Nellyana Salas ; Reseñas ; 135-149 ; trimestral ; Nivel analítico

This paper is centered in the valuation of the centrality of groups following aproblem-specific approach (Friedkin, 1991). Assuming a TU-game that reflects theinterests which motivate the interactions among individuals in a network, we extend thegame theoretic centrality measure of Gomez et al. (2003) to the case of groups, anddefine the game theoretic group centrality of a group as the variation of its value orpower due to their social relations. We rely on the Shapley group value (Flores et al.,2014) for measuring the value of a group in a game without any restriction, and weintroduce the Myerson group value in order to measure the value when the socialstructure is considered. ; This research has been supported by I+D+i research project MTM2011-27892 from the Government of Spain

Please cite this article as: A. Romero, C. Jiménez, J. González, P. López-Varo, M.J. Deen, J.A. Jiménez-Tejada, Compact modeling of the effects of illumination on the contact region of organic phototransistors, Organic Electronics, (2019), 70, 113-121. ; A good modeling of degrading effects in an electronic device, such as the contact region of organic phototransistors (OPTs), can be favorably used to better describe and optimize the performance of the whole device. Furthermore, a proper design of the contacts can enhance the exciton dissociation and the extraction of photogenerated charge in the device. In this work, a compact model for OPTs is developed. This model is valid for all the operation regimes of the transistors. It includes a model for the contact region of the device that incorporates the effects of illumination. The compact model and the contact region model are validated with published experimental data from several OPTs under different illumination conditions. The tool used to validate the model is an evolutionary parameter extraction procedure developed in a previous work. The results show that both photoconductive and photovoltaic effects impact the intrinsic region of the transistor, as well as the electrical behavior of the contact region. The parameters used in the contact region model are linked to these photovoltaic and photoconductive effects. ; This work was supported by projects MAT2016-76892-C3-3-R and TIN2015-67020-P funded by the Spanish Government and European Regional Development Funds (ERDF) and by "Beca de Iniciación a la Investigación para estudiantes de Grado" given by the University of Granada.

El fenómeno migratorio de menores no acompañados representa una realidad compleja que demanda respuestas integrales de protección de los derechos de la infancia migrante. El carácter global de las políticas e intervenciones socioeducativas también requiere de una mirada transdisciplinar y multiprofesional que logre atender las necesidades y demandas de estos niños y adolescentes. Desde este enfoque, la investigación presentada en este trabajo pretende conocer los procesos de inserción social y educativa de menores migrantes no acompañados en la provincia de Córdoba, integrando para ello, las miradas procedentes de diferentes sectores y agentes implicados en la intervención con este colectivo. En concreto, el estudio describe el perfil de los menores migrantes no acompañados que durante los años 2018 y 2019 llegaron a la provincia de Córdoba. Un análisis descriptivo, de corte cuantitativo, de los expedientes de estos menores ha permitido conocer su perfil, trayectorias vitales, escolares, su vida dentro de los centros de protección hasta alcanzar la mayoría de edad y sus aspiraciones futuras. Los resultados muestran que una mayoría de menores llega al país de destino con un trayecto migratorio ya definido desde el origen, y la provincia de Córdoba se establece como lugar de paso, siendo otros destinos los elegidos por la mayoría de estos menores sin referentes familiares. Por otro lado, entre las dificultades que se encuentran a su llegada al país de destino, destaca el bajo dominio del idioma, lo que dificulta el desarrollo satisfactorio de los estudios obligatorios. No obstante, una gran mayoría de estos jóvenes aprovechan las diferentes oportunidades de refuerzo que se ofrecen desde las distintas instituciones públicas y privadas. Los resultados muestran cómo estos menores presentan escasos problemas de convivencia dentro de los centros de protección y, en general, existen escasas denuncias durante su estancia en el país de acogida.

In this work, the topic of the detrimental contact effects in organic thin-film transistors (OTFTs) is revisited. In this case, contact effects are considered as a tool to enhance the characterization procedures of OTFTs, achieving more accurate values for the fundamental parameters of the transistor threshold voltage, carrier mobility and on-off current ratio. The contact region is also seen as a fundamental part of the device which is sensitive to physical, chemical and fabrication variables. A compact model for OTFTs, which includes the effects of the contacts, and a recent proposal of an associated evolutionary parameter extraction procedure are reviewed. Both the model and the procedure are used to assess the effect of the annealing temperature on a nickel-1,4,8,11,15,18,22,25-octakis(hexyl)phthalocyanine (NiPc6)-based OTFT. A review of the importance of phthalocyanines in organic electronics is also provided. The characterization of the contact region in NiPc6 OTFTs complements the results extracted from other physical–chemical techniques such as differential scanning calorimetry or atomic force microscopy, in which the transition from crystal to columnar mesophase imposes a limit for the optimum performance of the annealed OTFTs. ; This work was supported by projects MAT2016-76892-C3-3-R, TIN2015-67020-P and PGC2018-098813-B-C31 funded by the Spanish Government and "European Regional Development Funds (ERDF)". The experimental work was carried out at Queen Mary, University of London under financial support from the UK Technology Strategy Board (Project No: TP/6/EPH/6/S/K2536J). This work was also supported by NSERC Green Electronics Network (GreEN) (grant number: NETGP 508526-17).