Retrospective Interference Alignment for the 3-user MIMO Interference Channel with delayed CSIT

The degrees of freedom (DoF) of the 3-user multiple input multiple output interference channel (3-user MIMO IC) are investigated where there is delayed channel state information at the transmitters (dCSIT). We generalize the ideas of Maleki et al. about {\it Retrospective Interference Alignment (RIA)} to be applied to the MIMO IC, where transmitters and receivers are equipped with $(M,N)$ antennas, respectively. We propose a two-phase transmission scheme where the number of slots per phase and number of transmitted symbols are optimized by solving a maximization problem. Finally, we review the existing achievable DoF results in the literature as a function of the ratio between transmitting and receiving antennas $\rho=M/N$. The proposed scheme improves all other strategies when $\rho \in \left(\frac{1}{2}, \frac{31}{32} \right]$.Comment: Draft version of the accepted manuscript at IEEE ICASSP 1

Retrospective Interference Alignment for the MIMO Interference Broadcast Channel

The degrees of freedom (DoF) of the multiple-input multiple-output (MIMO) Interference Broadcast Channel (IBC) with 2 cells and 2 users per cell are investigated when only delayed channel state information is available at the transmitter side (delayed CSIT). Retrospective Interference Alignment has shown the benefits in terms of DoF of exploiting delayed CSIT for interference, broadcast and also for the IBC. However, previous works studying the IBC with delayed CSIT do not exploit the fact that the users of each cell are served by a common transmitter. This work presents a four-phase precoding strategy taking this into consideration. Assuming that transmitters and receivers are equipped with $M,N$ antennas, respectively, new DoF inner bounds are proposed, outperforming the existing ones for $\rho = \frac{M}{N} > 2.6413$.Comment: 1 copyright page + 5 paper pages + 3 appendix pages, Submitted to IEEE ISIT 201

Optimization of Radio and Computational Resources for Energy Efficiency in Latency-Constrained Application Offloading

Providing femto-access points (FAPs) with computational capabilities will allow (either total or partial) offloading of highly demanding applications from smart-phones to the so called femto-cloud. Such offloading promises to be beneficial in terms of battery saving at the mobile terminal (MT) and/or latency reduction in the execution of applications, whenever the energy and/or time required for the communication process are compensated by the energy and/or time savings that result from the remote computation at the FAPs. For this problem, we provide in this paper a framework for the joint optimization of the radio and computational resource usage exploiting the tradeoff between energy consumption and latency, and assuming that multiple antennas are available at the MT and the serving FAP. As a result of the optimization, the optimal communication strategy (e.g., transmission power, rate, precoder) is obtained, as well as the optimal distribution of the computational load between the handset and the serving FAP. The paper also establishes the conditions under which total or no offloading are optimal, determines which is the minimum affordable latency in the execution of the application, and analyzes as a particular case the minimization of the total consumed energy without latency constraints.Comment: Accepted to be published at IEEE Transactions on Vehicular Technology (acceptance: November 2014

La búsqueda de la realidad o de la verdad: una aproximación a partir de la teoría sociológica

El objetivo de este artículo es pensar el nexo de la búsqueda de la realidad o de la verdad con la metodología, al plantear preguntas a diversas corrientes teóricas y analizar las respuestas de cada autor o corriente al respecto. Desde la perspectiva teórica sociológica, se abordan dos niveles de reflexión con implicaciones metodológicas. El primero, hace referencia a las implicaciones metodológicas derivadas de la búsqueda de la realidad o de la verdad. El segundo, de carácter epistemológico, hace referencia a la dualidad teórica y paradigmática existente entre la capacidad subjetiva de decisión frente a la constricción de los sujetos por parte de las estructuras. The aim of this article is to think the relationship between the search for reality or the truth with methodology, by asking some questions to different theoretical perspectives and by analyzing different answers given by the authors and theories. From the sociological theoretical perspective, it deals with two levels of thought with methodological implications. The first refers to the methodological implications arising from the search for reality or truth. The second, epistemological, refers to the theoretical and paradigmatic duality between subjective capacity decisions against the constriction of the subjects by the structures

Teoría de la Decisión: Proceso de interacciones u organizaciones como sistemas de decisiones

We present a theoretical discussion of the sociological contribution concerning decisions in organizations.Two theories stand. The first, based on the decision process from a critical theory of the traditional linear multirational by Lucien Sfez, argues that the decision is a process of interactions and treats it as an institutional process based on the freedom of the subject. The second theory based on self-referentialsystems by Niklas Luhmann, interprets organizations as systems-making, and understands the concept of decision as purely epistemological specificity, abstracted from the decision of all the elements and organizational variables associated with it.Se expone un debate teórico sobre la aportación sociológica referente a las decisiones en las organizaciones. Sobresalen dos teorías de las decisiones. La primera, basada en el proceso de decisión a partir una teoría crítica de la multirracionalidad lineal elaborado por Lucien Sfez, al plantear que con la decisión se trata de un proceso de interacciones, al ser considerada como un proceso institucional fundamentado en la libertad del sujeto. La segunda fundamentada en la teoría de sistemas autorreferenciales, interpreta las organizaciones como sistemas de decisiones y entiende el concepto de decisión en su especificidad puramente epistemológica, al abstraer de la decisión de todos los elementos y variables organizacionales relacionados con ella (Niklas Luhmann

Políticas municipales de extranjería y multiculturalidad en Alemania

Los municipios son la primera institución pública que se ve confrontada con la realidad de la inmigración, al ser estos los que tienen la responsabilidades en diferentes campos de la vida cotidiana de los inmigrantes. El presente articulo se centra en las políticas municipales de inmigración en la República Federal Alemana, uno de los paises europeos con mayor número relativo y absoluto de inmigrantes procedentes de otros círculos culturales. La falta de medidas municipales preventivas y de una voluntad política de realizarlas, ha conducido a que, en diferentes ciudades, se hayan producido situaciones críticas y estallidos abiertos de violencia y xenofobia. En el trabajo se exponen los déficits y la duplicidad de las funciones municipales debido a la falta de conceptos referentes a la inmigración e integración de extranjeros en una ciudad con un elevado número de ellos, déficits que solamente son cubiertos por iniciativas de base creadas por los propios inmigrantes. No obstante, una alternativa a largo plazo sigue siendo el reconocimiento de la multiculturalidad y la creación de las correspondientes áreas municipales.Town councils are the primary public institution to be confronted with the reality of immigration, it is they that have the responsability in different areas of the inmigrants everyday life. This article centers on the policies of the town councils in the German Federal Republic, one of the European countries with the highest relative and absolute number of immigrants proveeding from other culture circles. The lack of preventive town council measures and of political will to achieve this has driven different cities who critical situations and oper explosions of violence and xenophobia. This article exposes the deficiencies and duplicity of local goverment policy and the lack of concepts relating to inmigration and integration of foreigners in a city with an elevated number of then deficits that are only coreved by initiatives of bases created by the inmigrants thenselves. However, an alternative in the long run continues being the recognition of multiculturality and the creation of the corresponding town council areas

La Iconografia del músic i de la música als dibuixos de la premsa barcelonina (1865-1936)

A partir del darrer terç del segle xix, amb una premsa catalana consolidada i de temàtica diversificada, s'editaren revistes musicals especialitzades que compartien l'espai editorial amb títols tan populars com les revistes il·lustrades La Campana de Gràcia o Cu-cut! Els grans dibuixants de premsa de l'entresegle van codificar la iconografia dels fets d'actualitat, quadres de costums i arquetips ciutadans, entre els quals trobem l'ens abstracte de la música i l'entitat concreta del personatge del músic. El bohemi incomprès o el mestre venerat foren els dos extrems d'aquesta iconografia. L'activitat musical reflectia també aquella Barcelona burgesa i obrera que s'esplaiava a les gales del Liceu, als cabarets del Raval o a les corals obreres. Els ninotaires van saber explotar la temàtica musical i transposar-la al camp polític, com va ser el cas de la caricatura de Joan Llaverias sobre els concerts que l'Orfeó Català va donar a Madrid i que el 1912 va suposar la suspensió definitiva del Cu-cut!As from the last third of the 19th century, with a consolidated Catalan press in a broad diversity of fields, music journals were published that shared their area of specialisation with such popular publications as the illustrated magazines La Campana de Gràcia and Cu-cut! The major draughtsmen of the turn-of-the-century press coded the iconography of current events, genre scenes and city archetypes, which included the abstract entity of music and the concrete entity of the musician. The misunderstood bohemian and the venerated maestro were the two extremes of this iconography. Musical activity also reflected the bourgeois and working-class Barcelona that found entertainment in the galas of the Liceu, the cabarets of the Raval quarter or the workers’ choirs. The cartoonists knew how to take advantage of musical subjects and shift them to the political terrain, as was the case of Joan Llaverias’s caricature of the concerts that the Orfeó Català held in Madrid, a caricature which led to the permanent closure of Cu-cut! in 1912