D2D Data Offloading in Vehicular Environments with Optimal Delivery Time Selection

Within the framework of a Device-to-Device (D2D) data offloading system for cellular networks, we propose a Content Delivery Management System (CDMS) in which the instant for transmitting a content to a requesting node, through a D2D communication, is selected to minimize the energy consumption required for transmission. The proposed system is particularly fit to highly dynamic scenarios, such as vehicular networks, where the network topology changes at a rate which is comparable with the order of magnitude of the delay tolerance. We present an analytical framework able to predict the system performance, in terms of energy consumption, using tools from the theory of point processes, validating it through simulations, and provide a thorough performance evaluation of the proposed CDMS, in terms of energy consumption and spectrum use. Our performance analysis compares the energy consumption and spectrum use obtained with the proposed scheme with the performance of two benchmark systems. The first one is a plain classic cellular scheme, the second is a D2D data offloading scheme (that we proposed in previous works) in which the D2D transmissions are performed as soon as there is a device with the required content within the maximum D2D transmission range..

Measuring complexity with zippers

Physics concepts have often been borrowed and independently developed by other fields of science. In this perspective a significant example is that of entropy in Information Theory. The aim of this paper is to provide a short and pedagogical introduction to the use of data compression techniques for the estimate of entropy and other relevant quantities in Information Theory and Algorithmic Information Theory. We consider in particular the LZ77 algorithm as case study and discuss how a zipper can be used for information extraction.Comment: 10 pages, 3 figure

A fast no-rejection algorithm for the Category Game

The Category Game is a multi-agent model that accounts for the emergence of shared categorization patterns in a population of interacting individuals. In the framework of the model, linguistic categories appear as long lived consensus states that are constantly reshaped and re-negotiated by the communicating individuals. It is therefore crucial to investigate the long time behavior to gain a clear understanding of the dynamics. However, it turns out that the evolution of the emerging category system is so slow, already for small populations, that such an analysis has remained so far impossible. Here, we introduce a fast no-rejection algorithm for the Category Game that disentangles the physical simulation time from the CPU time, thus opening the way for thorough analysis of the model. We verify that the new algorithm is equivalent to the old one in terms of the emerging phenomenology and we quantify the CPU performances of the two algorithms, pointing out the neat advantages offered by the no-rejection one. This technical advance has already opened the way to new investigations of the model, thus helping to shed light on the fundamental issue of categorization.Comment: 17 pages, 7 figure

Strategies for fast convergence in semiotic dynamics

Semiotic dynamics is a novel field that studies how semiotic conventions spread and stabilize in a population of agents. This is a central issue both for theoretical and technological reasons since large system made up of communicating agents, like web communities or artificial embodied agents teams, are getting widespread. In this paper we discuss a recently introduced simple multi-agent model which is able to account for the emergence of a shared vocabulary in a population of agents. In particular we introduce a new deterministic agents' playing strategy that strongly improves the performance of the game in terms of faster convergence and reduced cognitive effort for the agents.Comment: 6 pages, 6 figure

Evaluacion de exito y fracaso de tecnica ART en ninos de 3 a 6 anos atendidos en Cecof Brilla El Sol de Talca durante el 2008

76 p.La implementación de ART en Chile es consistente con la propuesta de OPS/OMS para el Plan de Salud Buco-dental decenal 2005 - 2015 de la Región de las Américas,que plantea entre sus metas el incremento de las intervenciones más costo efectivas y la ampliación de la cobertura de la atención odontológica con tecnologías sencillas, especialmente dirigida a grupos vulnerables. El MINSAL ha propuesto esta técnica para ser desarrollada en Centros Comunitarios Familiares (CECOF) que no están dotado de equipamiento odontológico convencional, en ellos se aplica la técnica ART en una camilla con instrumental específico, sin instrumental rotatorio, con luz frontal, sin unidad de agua ni aspiración. La finalidad es llegar a una mayor cantidad de personas vulnerables, permitiendo llegar a colegios, jardines infantiles incluso a hogares con una odontología comunitaria. Este estudio tuvo como objetivo obtener un análisis descriptivo del éxito y fracaso de la técnica ART en niños atendidos entre marzo a julio del año 2008 en (CECOF) Brilla el Sol de la ciudad de Talca. Se evaluaron 41 niños entre 3 a 6 años, tratados con la técnica ART realizada por un operador entre los meses de marzo a julio el año 2008 en el CECOF Brilla el Sol de la comuna de Talca. En ellos se evaluó el ART según los criterios para evaluación de,restauraciones y sellantes descritas según la OPS/OMS (2001), además de medición de c.e.o.d. según la OMS, 1997. En cuento a los resultados obtenidos, de las piezas evaluadas, 110 piezas fueron restauraciones, correspondientes a un 59,78% del total, y 74 piezas correspondieron a sellantes, constituyendo un 40,22% del total. Del total de 110 piezas restauradas con técnica ART, según los códigos de evaluación, en 22 piezas se determinó éxito, correspondiendo a un 20 %; en 85 piezas se determinó fracaso, correspondiente a un 77, 27%. Del un total de 74 piezas selladas con vidrio ionómero, 18 de ellas se evaluaron de manera exitosa, correspondiendo a un 24,32%, y 56 de ellas se evaluaron como fracaso de la técnica, correspondiendo a un 75,68%. Palabras clave: Técnica de Restauración Atraumática (ART), restauraciones, sellantes, éxito, fracaso

Diabetic kidney disease. new clinical and therapeutic issues. Joint position statement of the Italian Diabetes Society and the Italian Society of Nephrology on "the natural history of diabetic kidney disease and treatment of hyperglycemia in patients with type 2 diabetes and impaired renal function"

Recent epidemiological studies have disclosed heterogeneity in diabetic kidney disease (DKD). In addition to the classical albuminuric phenotype, two new phenotypes have emerged, i.e., “nonalbuminuric renal impairment” and “progressive renal decline”, suggesting that DKD progression toward end-stage kidney disease in diabetic patients may occur through two distinct pathways heralded by a progressive increase in albuminuria and decline in renal function independent of albuminuria, respectively. Besides the natural history of DKD, also the management of hyperglycemia in patients with type 2 diabetes and reduced renal function has profoundly changed in the last two decades. New anti-hyperglycemic drugs have become available for treatment of these individuals and the lowest estimated glomerular filtration rate safety thresholds for some of the old agents have been reconsidered. This joint document of the Italian Diabetes Society (SID) and the Italian Society of Nephrology (SIN) reviews the natural history of DKD in the light of the recent epidemiological literature and provides updated recommendations on anti-hyperglycemic treatment with non-insulin agents in DKD patients

Metodología de redes bayesianas para estimar el costo probable de proyectos de agua potable rural

Tesis (Ingeniero Civil)El presente estudio incursiona en las redes bayesianas aplicadas a proyectos de agua potable rural realizados en la Región de Los Ríos, Chile. Las redes bayesianas se caracterizan por ser grafos acíclicos dirigidos, es decir, relacionan variables representadas por nodos y permiten visualizar fácilmente las relaciones de dependencia entre ellas. La metodología considera, la identificación de las variables o nodos con sus respectivos estados, la configuración de la red piloto y a partir de los antecedentes de los proyectos de agua potable rural la construcción de las tablas de probabilidad condicional. En términos de resultados, se trabajó con dos topologías, las cuales estaban conformadas por las ocho variables identificadas en los proyectos de agua potable rural. Se encontró que la topología número dos, proporcionaba mejores resultados en términos de predicción probabilística además de tener mejores estadísticos de evaluación como son pérdida logarítmica, compensación esférica, pérdida cuadrática. Finalmente la validación y la evaluación de la red en términos de la predicción del costo probable de los proyectos del grupo de control. A partir de la metodología utilizada se observa una buena aproximación en términos de probabilidades para estimación de costos de este tipo de proyectos, aunque, el disponer de mayor número de datos incrementará el nivel de precisión.The present study ventures into Bayesian networks applied to rural drinking water projects carried out in the Region of Rivers,Chile. Bayesian networks are characterized by being directed acyclic graph, that is, related variables represented by nodes and let you easily view the dependency relationships between them. The methodology considers the identification of variables or nodes with their respective states, the configuration of the pilot network and from the 2 history of the rural drinking water project construction of conditional probability tables. In terms of results, we worked with two typologies which were comprised of the eight variables identified in the rural drinking water projects. It was found that typology two provided better probabilistic forecasting results, as well as having better statistical evaluation capacity in areas such as are logarithmic loss, spherical compensation, and quadratic loss. Finally validation and evaluation of the network in terms of predicting the likely cost of the projects in the control group. From the methodology used a good approximation is observed in terms of probabilities to estimate costs of such projects, although, the availability of more data increases the level of accuracy