RADIC II: a fault tolerant architecture with flexible dynamic redundancy

The demand for computational power has been leading the improvement of the High Performance Computing (HPC) area, generally represented by the use of distributed systems like clusters of computers running parallel applications. In this area, fault tolerance plays an important role in order to provide high availability isolating the application from the faults effects. Performance and availability form an undissociable binomial for some kind of applications. Therefore, the fault tolerant solutions must take into consideration these two constraints when it has been designed. In this dissertation, we present a few side-effects that some fault tolerant solutions may presents when recovering a failed process. These effects may causes degradation of the system, affecting mainly the overall performance and availability. We introduce RADIC-II, a fault tolerant architecture for message passing based on RADIC (Redundant Array of Distributed Independent Fault Tolerance Controllers) architecture. RADIC-II keeps as maximum as possible the RADIC features of transparency, decentralization, flexibility and scalability, incorporating a flexible dynamic redundancy feature, allowing to mitigate or to avoid some recovery side-effects.

System analysis of a Peer-to-Peer Video-on-Demand architecture: Kangaroo

Architectural design and deployment of Peer-to-Peer Video-on-Demand (P2PVoD) systems which support VCR functionalities is attracting the interest of an increasing number of research groups within the scientific community; especially due to the intrinsic characteristics of such systems and the benefits that peers could provide at reducing the server load. This work focuses on the performance analysis of a P2P-VoD system considering user behaviors obtained from real traces together with other synthetic user patterns. The experiments performed show that it is feasible to achieve a performance close to the best possible. Future work will consider monitoring the physical characteristics of the network in order to improve the design of different aspects of a VoD system.

Trans-Atlantic Pedagogy for Teaching Pre-Service Teachers ICT: Bringing forward cultural issues

Projecte de recerca elaborat a partir d’una estada a la Universitat de Toronto, Canadà, des d’octubre del 2006 a febrer del 2007. El projecte Barchito és un projecte Interrnacional que va involucrar tres universitats: La Universitat Autònoma de Barcelona, la Universitat de Toronto (Canadà) i la Universitat de Roosevelt (USA). El seu objectiu principal era posar en contacte estudiants de les tres universitats (de tres cursos diferents) per discutir al voltant de temes com ara l'ensenyament/aprenentatge i elements culturals de cada país. Aquest projecte presenta la natura de l'experiència des de la visió dels participants: alumnat i professorat. Superant diferències inicials de llengua, els participants van aprendre d'altra cultura, van aprendre sobre altres maneres d'ensenyar i van aprendre, en definitiva, sobre ells mateixos. L'eina d'aprenentatge col.laboratiu els va ajudar a sobrepassar el context immediat, emprant per això, l'eina tecnològica anomenada: Knowledge Forum.

Scheduled service versus personal transportation: the role of distance

This paper analyzes both theoretically and empirically the relationship between distance and frequency of scheduled transportation services. We study the interaction between a monopoly firm providing high-speed scheduled service and personal trans- portation (i.e., car). Most interestingly, the carrier chooses to increase frequency of service on longer routes when competing with personal transportation because provid- ing a higher frequency (at extra cost) it can also charge higher fares that can boost its profits. However, when driving is not a relevant option, frequency of service de- creases for longer flights consistently with prior studies. An empirical application of our analysis to the European airline industry con?rms the predictions of our theoretical model.

Study of the influence of grain size and precipitates on the electromagnetic losses in different grades of non-oriented fully processed electrical steel

The study was performed in the installations of OCAS, a Steel Research Centre of ArcelorMittal. Taking M32 steel (3.25%Si+0.9%Al) as the basis chemical composition and three different thicknesses (0.35, 0.5 and 0.65mm), different annealing conditions (temperature and time) have been applied in the laboratory simulator at St. Chély, France. The aim was to link annealing parameters, grain size and energy loss. It was determined the optimum annealing parameters to reach the lowest power losses for three different grades of non-oriented fully processed electrical steel. In addition, M250-50 samples having different magnetic behaviour (high and low losses) but the same grain size and texture, have been analyzed in terms of TEM observations of their precipitates, in the University of Marseille. The results reveal that a high amount of medium and big precipitates (&10 nm) worsen the magnetic properties of the material. The small precipitates (&10nm) do not have a strong influence on the magnetic properties. The presence of precipitates can have a great influence on the power losses and further work is clearly necessary.

Link between microstructure and properties in new metallurgical concepts for very low loss non-oriented electrical steel

The influence of chemistry and soaking temperature (maximal temperature of the continuous annealing) on the final properties of non-oriented electrical steels has been studied. With this objective two different studies have been performed. First the Mn, Ni and Cr content of a low loss electrical steel composition has been modified. An intermediate content and a high content of each element has been added in order to study the influence of this components on the magnetic looses, grain size and texture. Secondly the influence of the soaking temperature on magnetic properties, grain size and oxidation in four grades of non-oriented electrical steels (Steel A, B, C and D) was studied.

Disseny d'un sistema HW/SW de control remot amb dispositius FPGA

El projecte que es presenta a continuació, té com a objectiu implementar un sistema HW/SW encastat en una FPGA, capaç d’executar funcions de control remot per infraroig en plataformes de televisió flexibles de Sony Corp. El disseny obtingut, s’incorporarà a un sistema més ampli de verificació i test de circuits impresos, dins del marc de producció SMD. La finalitat d’aquest projecte, és la realització d’un sistema flexible per a la implementació de comandaments de comunicació per infraroig amb circuits impresos. Prèviament, s’ha estudiat els conceptes bàsics referents a la implementació de sistemes amb FPGAs, la seva metodologia de desenvolupament i les principals característiques de la seva arquitectura. Com a especificacions, s’ha utilitzat l’estàndard de control remot per infraroig de Sony Corp SIRCS (Sony Infrared remote control system).