Relación entre el concepto de límite y los conceptos topológicos

A través de una prueba aplicada a alumnos de 4to y 5to año se establece la correlación existente entre el concepto de límite y el concepto de entorno. Las características de las respuestas obtenidas permite una calificación de las mismas que van desde las que evidencian un pensamiento en el nivel concreto a las respuestas que consideran el modelo matemático apto para cada circunstancia. Desde un planteo teórico se estudian las dificultades en la comprensión del continuo geométrico y la aparente ruptura con la completitud del conjunto de los números reales

Aspectos clínicos del síndrome de Ehlers-Danlos

Se realiza una revisión bibliográfica de conjunto de los aspectos clínicos más significativos del síndrome de Ehlers-Danlos. Se recogen datos estadísticos, características raciales, morfotipo e interpretación patogénica actual. Se ha prestado especial atención a su comportamiento hereditario y su fácil confusión con otras afecciones musculares o neurogénicas. Se analizan sus síntomas más característicos, formas clínicas y complicaciones neurológicas, intestinales, cardíacas, vasculares y cutáneas.A review of the literature concerning the most significant clinical aspects of the Ehlers-Danlos syndrome is presented. Statistical data, race characteristics, morphotype and current pathogenic theories are summarised. Special atention has been paid to the hereditary behaviour and the easy misdiagnosis with other muscular and neurological entities. The usual symptoms, clinical types, neurological, cardiac, vascular and cutaneous complications are discussed

Sequential pivotal mechanisms for public project problems

It is well-known that for several natural decision problems no budget balanced Groves mechanisms exist. This has motivated recent research on designing variants of feasible Groves mechanisms (termed as `redistribution of VCG (Vickrey-Clarke-Groves) payments') that generate reduced deficit. With this in mind, we study sequential mechanisms and consider optimal strategies that could reduce the deficit resulting under the simultaneous mechanism. We show that such strategies exist for the sequential pivotal mechanism of the well-known public project problem. We also exhibit an optimal strategy with the property that a maximal social welfare is generated when each player follows it. Finally, we show that these strategies can be achieved by an implementation in Nash equilibrium.Comment: 19 pages. The version without the appendix will appear in the Proc. 2nd International Symposium on Algorithmic Game Theory, 200

Welfare and Revenue Guarantees for Competitive Bundling Equilibrium

We study equilibria of markets with $m$ heterogeneous indivisible goods and $n$ consumers with combinatorial preferences. It is well known that a competitive equilibrium is not guaranteed to exist when valuations are not gross substitutes. Given the widespread use of bundling in real-life markets, we study its role as a stabilizing and coordinating device by considering the notion of \emph{competitive bundling equilibrium}: a competitive equilibrium over the market induced by partitioning the goods for sale into fixed bundles. Compared to other equilibrium concepts involving bundles, this notion has the advantage of simulatneous succinctness ($O(m)$ prices) and market clearance. Our first set of results concern welfare guarantees. We show that in markets where consumers care only about the number of goods they receive (known as multi-unit or homogeneous markets), even in the presence of complementarities, there always exists a competitive bundling equilibrium that guarantees a logarithmic fraction of the optimal welfare, and this guarantee is tight. We also establish non-trivial welfare guarantees for general markets, two-consumer markets, and markets where the consumer valuations are additive up to a fixed budget (budget-additive). Our second set of results concern revenue guarantees. Motivated by the fact that the revenue extracted in a standard competitive equilibrium may be zero (even with simple unit-demand consumers), we show that for natural subclasses of gross substitutes valuations, there always exists a competitive bundling equilibrium that extracts a logarithmic fraction of the optimal welfare, and this guarantee is tight. The notion of competitive bundling equilibrium can thus be useful even in markets which possess a standard competitive equilibrium

Resultados preliminares de la aplicación del algoritmo Heliosat-2 para la estimación de la irradiación solar global a partir de imágenes satelitales GOES-13 en la región de la Pampa Húmeda argentina

En este trabajo se informa un resultado preliminar de la aplicación del algoritmo Heliosat-2 al análisis de series temporales de imágenes de la región pampeana tomadas por el satélite GOES-13 de la NASA en Diciembre de 2013. Los valores de irradiación horaria global deducidos mediante el algoritmo fueron contrastados con medidas tomadas en tierra durante el mismo período en las diez estaciones solarimétricas de la Red Solarimétrica Regional de la Universidad Nacional de Luján en la Pampa Húmeda, Argentina. Los primeros resultados obtenidos muestran para la irradiación diaria en tierra un RMSE promedio del orden del 10 %. Estos resultados preliminares sugieren que el método resulta adecuado para la evaluación de la irradiación solar en tierra a partir de imágenes satelitales y, tras análisis y ajustes más refinados, podrá ser aplicado a la elaboración de mapas de irradiación para todo el territorio de nuestro país.This study reports a preliminary result of the application of the Heliosat-2 algorithm to the analysis of time series of images of the pampean region taken by the NASA GOES-13 satellite in December 2013. The inferred values of hourly global irradiation using the algorithm were contrasted with land measurements taken during the same period at ten solarimetric stations of the Red Solarimetrica Regional of the Universidad Nacional de Luján in the humid Pampa, Argentina. This first results show for daily irradiation estimates an average RMSE around 10%. These preliminary results suggest that the method is appropriate for the evaluation of the solar irradiation at Earth from satellite images and, after analysis and most refined settings, can be applied to the elaboration of maps of irradiation for the entire territory of our country.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Distributed Resource Allocation for Stream Data Processing

Abstract. Data streaming applications are becoming more and more common due to the rapid development in the areas such as sensor net-works, multimedia streaming, and on-line data mining, etc. These ap-plications are often running in a decentralized, distributed environment. The requirements for processing large volumes of streaming data at real time have posed many great design challenges. It is critical to optimize the ongoing resource consumption of multiple, distributed, cooperating, processing units. In this paper, we consider a generic model for the gen-eral stream data processing systems. We address the resource alloca-tion problem for a collection of processing units so as to maximize the weighted sum of the throughput of different streams. Each processing unit may require multiple input data streams simultaneously and pro-duce one or many valuable output streams. Data streams flow through such a system after processing at multiple processing units. Based on this framework, we develop distributed algorithms for finding the best resource allocation schemes in such data stream processing networks. Performance analysis on the optimality and complexity of these algo-rithms are also provided

Preferences under ignorance

A decision maker (DM) makes choices from different sets of alternatives. The DM is initially ignorant of the payoff associated with each alternative, and learns these payoffs only after a large number of choices have been made. We show that, in the presence of an outside option, once payoffs are learned, the optimal choice rule from sets of alternatives can be rationalized by a DM with strict preferences over all alternatives. Under this model, the DM has preferences for preferences while being ignorant of what preferences are “right”