Anàlisi, disseny i construcció d'un robot educatiu basat en microcontrolador AVR-ATMEGA

Aquest projecte presenta el disseny, construcció i programació d’un robot autònom, com a base per una proposta educativa. Per aconseguir aquest objectiu s’ha dotat el robot d’una unitat de procés, un sistema de locomoció i un seguit de sensors que proporcionaran a la unitat informació respecte l’entorn. Per gestionar totes aquestes funcionalitats, s’ha fet servir un sistema operatiu en temps real capaç de gestionar amb efectivitat les tasques que puguin ser executades pel robot. Finalment, s’ha exposat una detallada descripció dels costos per una producció de volum mig i de caire merament educatiu.

Econometrics on GPUs

A graphical processing unit (GPU) is a hardware device normally used to manipulate computer memory for the display of images. GPU computing is the practice of using a GPU device for scientific or general purpose computations that are not necessarily related to the display of images. Many problems in econometrics have a structure that allows for successful use of GPU computing. We explore two examples. The first is simple: repeated evaluation of a likelihood function at different parameter values. The second is a more complicated estimator that involves simulation and nonparametric fitting. We find speedups from 1.5 up to 55.4 times, compared to computations done on a single CPU core. These speedups can be obtained with very little expense, energy consumption, and time dedicated to system maintenance, compared to equivalent performance solutions using CPUs. Code for the examples is provided.

Distributed all-atom simulations of intrinsically unstructured proteins

The Computational Biophysics Group at the Universitat Pompeu Fabra (GRIB-UPF) hosts two unique computational resources dedicated to the execution of large scale molecular dynamics (MD) simulations: (a) the ACMD molecular-dynamics software, used on standard personal computers with graphical processing units (GPUs); and (b) the GPUGRID. net computing network, supported by users distributed worldwide that volunteer GPUs for biomedical research. We leveraged these resources and developed studies, protocols and open-source software to elucidate energetics and pathways of a number of biomolecular systems, with a special focus on flexible proteins with many degrees of freedom. First, we characterized ion permeation through the bactericidal model protein Gramicidin A conducting one of the largest studies to date with the steered MD biasing methodology. Next, we addressed an open problem in structural biology, the determination of drug-protein association kinetics; we reconstructed the binding free energy, association, and dissaciociation rates of a drug like model system through a spatial decomposition and a Makov-chain analysis. The work was published in the Proceedings of the National Academy of Sciences and become one of the few landmark papers elucidating a ligand-binding pathway. Furthermore, we investigated the unstructured Kinase Inducible Domain (KID), a 28-peptide central to signalling and transcriptional response; the kinetics of this challenging system was modelled with a Markovian approach in collaboration with Frank Noe’s group at the Freie University of Berlin. The impact of the funding includes three peer-reviewed publication on high-impact journals; three more papers under review; four MD analysis components, released as open-source software; MD protocols; didactic material, and code for the hosting group.

Dynamic estimation of three-dimensional cerebrovascular deformation from rotational angiography

Purpose: The objective of this study is to investigate the feasibility of detecting and quantifying 3D cerebrovascular wall motion from a single 3D rotational x-ray angiography (3DRA) acquisition within a clinically acceptable time and computing from the estimated motion field for the further biomechanical modeling of the cerebrovascular wall. Methods: The whole motion cycle of the cerebral vasculature is modeled using a 4D B-spline transformation, which is estimated from a 4D to 2D + t image registration framework. The registration is performed by optimizing a single similarity metric between the entire 2D + t measured projection sequence and the corresponding forward projections of the deformed volume at their exact time instants. The joint use of two acceleration strategies, together with their implementation on graphics processing units, is also proposed so as to reach computation times close to clinical requirements. For further characterizing vessel wall properties, an approximation of the wall thickness changes is obtained through a strain calculation. Results: Evaluation on in silico and in vitro pulsating phantom aneurysms demonstrated an accurate estimation of wall motion curves. In general, the error was below 10% of the maximum pulsation, even in the situation when substantial inhomogeneous intensity pattern was present. Experiments on in vivo data provided realistic aneurysm and vessel wall motion estimates, whereas in regions where motion was neither visible nor anatomically possible, no motion was detected. The use of the acceleration strategies enabled completing the estimation process for one entire cycle in 5-10 min without degrading the overall performance. The strain map extracted from our motion estimation provided a realistic deformation measure of the vessel wall. Conclusions: The authors' technique has demonstrated that it can provide accurate and robust 4D estimates of cerebrovascular wall motion within a clinically acceptable time, although it has to be applied to a larger patient population prior to possible wide application to routine endovascular procedures. In particular, for the first time, this feasibility study has shown that in vivo cerebrovascular motion can be obtained intraprocedurally from a 3DRA acquisition. Results have also shown the potential of performing strain analysis using this imaging modality, thus making possible for the future modeling of biomechanical properties of the vascular wall.

Taking on new challenges in multi-word unit processing for Machine Translation

This paper discusses the qualitativecomparative evaluation performed on theresults of two machine translation systemswith different approaches to the processing ofmulti-word units. It proposes a solution forovercoming the difficulties multi-word unitspresent to machine translation by adopting amethodology that combines the lexicongrammar approach with OpenLogos ontologyand semantico-syntactic rules. The paper alsodiscusses the importance of a qualitativeevaluation metrics to correctly evaluate theperformance of machine translation engineswith regards to multi-word units.

The Multiple-partners assignment game with heterogeneous sales and multi-unit demands: competitive equilibria

A multiple-partners assignment game with heterogeneous sales and multiunit demands consists of a set of sellers that own a given number of indivisible units of (potentially many different) goods and a set of buyers who value those units and want to buy at most an exogenously fixed number of units. We define a competitive equilibrium for this generalized assignment game and prove its existence by using only linear programming. In particular, we show how to compute equilibrium price vectors from the solutions of the dual linear program associated to the primal linear program defined to find optimal assignments. Using only linear programming tools, we also show (i) that the set of competitive equilibria (pairs of price vectors and assignments) has a Cartesian product structure: each equilibrium price vector is part of a competitive equilibrium with all optimal assignments, and vice versa; (ii) that the set of (restricted) equilibrium price vectors has a natural lattice structure; and (iii) how this structure is translated into the set of agents' utilities that are attainable at equilibrium.

Desenvolupament d'un Videojoc en 3D basat en OPENGL

L'objectiu d'aquest treball ha estat desenvolupar un videojoc en un entorn de tres dimensions utilitzant les llibreries gràfiques d'OpenGL. Aquesta aplicació s'ha desenvolupat en Java, cosa que dóna més independència perquè aquesta és precisament la filosofia d'aquest llenguatge de programació.

Beyond Smith's rule: An optimal dynamic index, rule for single machine stochastic scheduling with convex holding costs

Most research on single machine scheduling has assumedthe linearity of job holding costs, which is arguablynot appropriate in some applications. This motivates ourstudy of a model for scheduling $n$ classes of stochasticjobs on a single machine, with the objective of minimizingthe total expected holding cost (discounted or undiscounted). We allow general holding cost rates that are separable,nondecreasing and convex on the number of jobs in eachclass. We formulate the problem as a linear program overa certain greedoid polytope, and establish that it issolved optimally by a dynamic (priority) index rule,whichextends the classical Smith's rule (1956) for the linearcase. Unlike Smith's indices, defined for each class, ournew indices are defined for each extended class, consistingof a class and a number of jobs in that class, and yieldan optimal dynamic index rule: work at each time on a jobwhose current extended class has larger index. We furthershow that the indices possess a decomposition property,as they are computed separately for each class, andinterpret them in economic terms as marginal expected cost rate reductions per unit of expected processing time.We establish the results by deploying a methodology recentlyintroduced by us [J. Niño-Mora (1999). "Restless bandits,partial conservation laws, and indexability. "Forthcomingin Advances in Applied Probability Vol. 33 No. 1, 2001],based on the satisfaction by performance measures of partialconservation laws (PCL) (which extend the generalizedconservation laws of Bertsimas and Niño-Mora (1996)):PCL provide a polyhedral framework for establishing theoptimality of index policies with special structure inscheduling problems under admissible objectives, which weapply to the model of concern.

Improving the efficiency of PV low-power processing circuits by selecting an optimal inductor current of the DC/DC converter

In the context of autonomous sensors powered by small-size photovoltaic (PV) panels, this work analyses how the efficiency of DC/DC-converter-based power processing circuits can be improved by an appropriate selection of the inductor current that transfers the energy from the PV panel to a storage unit. Each component of power losses (fixed, conduction and switching losses) involved in the DC/DC converter specifically depends on the average inductor current so that there is an optimal value of this current that causes minimal losses and, hence, maximum efficiency. Such an idea has been tested experimentally using two commercial DC/DC converters whose average inductor current is adjustable. Experimental results show that the efficiency can be improved up to 12% by selecting an optimal value of that current, which is around 300-350 mA for such DC/DC converters.

ParallelKnoppix - Rapid deployment of a linux cluster for MPI parallel processing using non-dedicated computers

This note describes ParallelKnoppix, a bootable CD that allows creation of a Linux cluster in very little time. An experienced user can create a cluster ready to execute MPI programs in less than 10 minutes. The computers used may be heterogeneous machines, of the IA-32 architecture. When the cluster is shut down, all machines except one are in their original state, and the last can be returned to its original state by deleting a directory. The system thus provides a means of using non-dedicated computers to create a cluster. An example session is documented.

Memòria: estada a London South Bank University (Regne Unit)

Investigación producida a partir de una estancia en la London South Bank University, Reino Unido, entre los meses de setiembre y diciembre del 2005. Se estudia el trabajo sexual en el Reino Unido desde tres perspectivas diferentes. Por una parte, se trata la historia del feminismo anglosajón respecto a sus visiones sobre la prostitución, desde una aproximación a las fuentes. Por otra parte, se plantea la situación jurídico-política. Finalmente, se presenta brevemente a las principales entidades que dan apoyo al colectivo de trabajadoras del sexo en la ciudad de Londres.

Weighted Hardy spaces for the unit disc: approximation properties

In this paper we study basic properties of the weighted Hardy space for the unit disc with the weight function satisfying Muckenhoupt's (Aq) condition, and study related approximation problems (expansion, moment and interpolation) with respect to two incomplete systems of holomorphic functions in this space.

Effect of high pressure processing on the microbiology of skin-vacuum packaged sliced meat products: cooked pork ham, dry cured pork ham and marinated beef loin

High hydrostatic pressure is being increasingly investigated in food processing. It causes microbial inactivation and therefore extends the shelf life and enhances the safety of food products. Yeasts, molds, and vegetative cells of bacteria can be inactivated by pressures in the range of 200 to 700 MPa. Microorganisms are more or less sensitive to pressure depending on several factors such as type, strain and the phase or state of the cells. In general, Gram-positive organisms are usually more resistant than Gram-negative. High pressure processing modifies the permeability of the cell membrane, the ion exchange and causes changes in morphology and biochemical reactions, protein denaturations and inhibition of genetic mechanisms. High pressure has been used successfully to extend the shelf life of high-acid foods such as refrigerated fruit juices, jellies and jams. There is now an increasing interest in the use of this technology to extend the shelf life of low-acid foods such as different types of meat products.

Bioequivalence of meat products treated with high pressure processing

The effects of high pressure on the composition of food products have not been evaluated extensively. Since, it is necessary to take in consideration the possible effects in basis to the changes induced in the bio molecules by the application of high pressures. The main effect on protein is the denaturation, because the covalent bonds are not affected; however hydrogen bonding, hydrophobic and intermolecular interactions are modified or destroyed. 1 High pressure can modify the activity of some enzymes. If this is done the proteolysis and lipolysis could be more or less intense and the content of free amino acids and fatty acids will be different. This could be related to the bioavailability of these compounds. Low pressures (100 MPa) have been shown to activate some enzymes (monomeric enzymes). Higher pressures induce loss of the enzyme activity. However some enzymes are very stable (ex. Lipase ~ 600 - 1000 MPa). Lipoxygenase is less stable, and there is little information about the effects on antioxidant enzymes. Other important issue is the influence of high pressure on oxidation susceptibility. This could modify the composition of lipids if the degree of the oxidation would have been higher or lower than in the traditional product. Pressure produces the damage of cell membranes favouring the contact between substrates and enzymes, exposure to oxidation of membrane fatty acids and loos of the efficiency of vitamin E. These effects can also affect to protein oxidation. In this study different compounds were analysed to establish the differences between non-treated and high-pressure treated products.

Política de la competència de la Unió Europea en el sector audiovisual. El cas dels operadors públics estatals de televisió a Espanya i el Regne Unit: RTVE i BBC

Estudi elaborat a partir d’una estada al Center for Socio-Legal Studies de la Universitat d’Oxford, Gran Bretanya, entre setembre del 2006 i gener del 2007. L'objectiu d'aquesta recerca ha estat determinar i avaluar com la política de la competència de la Unió Europea ha contribuït a la configuració del sector públic televisiu espanyol i britànic. El marc teòric està basat en el concepte d’ “europeització”, desenvolupat per Harcourt (2002) en el sector de mitjans, i que implica una progressiva referencialitat de les polítiques estatals amb les europees mitjançant dos mecanismes: la redistribució de recursos i els efectes en la socialització de la política europea. Per tal de verificar aquest impacte en el sector televisiu, la recerca ha desenvolupat una aproximació en dues etapes. En primer lloc, a banda de fer un inicial repàs bibliogràfic s'han estudiat les accions de la Comissió Europea en aquest terreny, sobre tot la Comunicació sobre aplicació de la reglamentació d'ajudes públiques al sector de la radiodifusió de 2001. En una segona etapa, s'han desenvolupat un seguit d'entrevistes personals a directius i polítics del sector a Brussel•les, Londres i Madrid. Els resultats de la recerca mostren que el procés d’Europeïtzació es un fenomen creixent en el sector audiovisual públic a Espanya i el Regne Unit, però que encara les peculiaritats estatals juguen un factor preponderant en regular aquesta influència de la UE. L'anàlisi de les entrevistes qualitatives mostren també que hi ha una relació inversament proporcional entre la tradició democràtica i el grau d’influència i de referència que suposa la UE en el sector audiovisual. Mentre que el Regne Unit, l'acció de la política de la competència de la UE es percep com a element suplementari, a Espanya la seva referencialitat ha estat clau, tot i que no decisiva, per la reforma dels mitjans públics estatals.