Usabilitat en les pàgines web

Aquest treball de final de carrera tracta sobre la facilitat d'ús en els llocs web, la importància de tenir en compte aquest aspecte quan es dissenyen llocs i la manera d'avaluar-los. Aquesta avaluació de la facilitat d'ús s'ha centrat en webs de l'entorn d'Humanidades, i concretament en els webs d'acadèmies científiques.

El Pla d'Acollida de Centre : una proposta intercultural del tractament a la diversitat

El projecte recull un treball d'assessorament en centres de primària pel que fa a l'elaboració del pla d'acollida. L'assessorament tenia una doble finalitat: dotar el centre d'una eina que el permetés sistematitzar-la i dotar de coherència i continuïtat els dubtes o angoixes que aquesta situació provocava. La base teòrica és doble: l'enfocament constructivista de l'assessorament psicopedagògic i la perspectiva de l'interculturalisme, atès el vessant socialitzador, interactiu i harmonitzador del PdA i la consideració social i sistèmica dels dos referents. La metodologia utilitzada ha estat qualitativa: la investigació-acció, ja que és un assessorament orientat cap a l'acció i basat en la pràctica, amb la finalitat de capacitar els docents en la millora d'aquesta pràctica. Recull aspectes organitzatius -matriculació, adscripció al curs, acollida i relació entre la família i el centre, llengua, recursos interns i suports externs- i coordinacions i estratègies d'aula -acollida, organització i funcionament de la classe, planificació de l'escolarització i activitats. Van quedar pendents de realitzar els aspectes referents al currículum i a la cooperació amb l'entorn.

Estat de la qüestió de l'estudi de l'aspecte lèxic : una proposta cognitiva de classficació d'esdeveniments

Peer-reviewed

Mètodes empírics en lingüística cognitiva

Peer-reviewed

Analyzing shapes as compositions of distances

We propose to analyze shapes as “compositions” of distances in Aitchison geometry asan alternate and complementary tool to classical shape analysis, especially when sizeis non-informative.Shapes are typically described by the location of user-chosen landmarks. Howeverthe shape – considered as invariant under scaling, translation, mirroring and rotation– does not uniquely define the location of landmarks. A simple approach is to usedistances of landmarks instead of the locations of landmarks them self. Distances arepositive numbers defined up to joint scaling, a mathematical structure quite similar tocompositions. The shape fixes only ratios of distances. Perturbations correspond torelative changes of the size of subshapes and of aspect ratios. The power transformincreases the expression of the shape by increasing distance ratios. In analogy to thesubcompositional consistency, results should not depend too much on the choice ofdistances, because different subsets of the pairwise distances of landmarks uniquelydefine the shape.Various compositional analysis tools can be applied to sets of distances directly or afterminor modifications concerning the singularity of the covariance matrix and yield resultswith direct interpretations in terms of shape changes. The remaining problem isthat not all sets of distances correspond to a valid shape. Nevertheless interpolated orpredicted shapes can be backtransformated by multidimensional scaling (when all pairwisedistances are used) or free geodetic adjustment (when sufficiently many distancesare used)

WMR navigation using local potential field corridors and narrow local occupancy grid perception

Path planning and control strategies applied to autonomous mobile robots should fulfil safety rules as well as achieve final goals. Trajectory planning applications should be fast and flexible to allow real time implementations as well as environment interactions. The methodology presented uses the on robot information as the meaningful data necessary to plan a narrow passage by using a corridor based on attraction potential fields that approaches the mobile robot to the final desired configuration. It employs local and dense occupancy grid perception to avoid collisions. The key goals of this research project are computational simplicity as well as the possibility of integrating this method with other methods reported by the research community. Another important aspect of this work consist in testing the proposed method by using a mobile robot with a perception system composed of a monocular camera and odometers placed on the two wheels of the differential driven motion system. Hence, visual data are used as a local horizon of perception in which trajectories without collisions are computed by satisfying final goal approaches and safety criteria

An improved method for discovering link criticality in transport networks

Quantitatively assessing the importance or criticality of each link in a network is of practical value to operators, as that can help them to increase the network's resilience, provide more efficient services, or improve some other aspect of the service. Betweenness is a graph-theoretical measure of centrality that can be applied to communication networks to evaluate link importance. However, as we illustrate in this paper, the basic definition of betweenness centrality produces inaccurate estimations as it does not take into account some aspects relevant to networking, such as the heterogeneity in link capacity or the difference between node-pairs in their contribution to the total traffic. A new algorithm for discovering link centrality in transport networks is proposed in this paper. It requires only static or semi-static network and topology attributes, and yet produces estimations of good accuracy, as verified through extensive simulations. Its potential value is demonstrated by an example application. In the example, the simple shortest-path routing algorithm is improved in such a way that it outperforms other more advanced algorithms in terms of blocking ratio

Digital beamforming and moving target indication for future spaceborne synthetic aperture radar

During the last decade the interest on space-borne Synthetic Aperture Radars (SAR) for remote sensing applications has grown as testified by the number of recent and forthcoming missions as TerraSAR-X, RADARSAT-2, COSMO-kyMed, TanDEM-X and the Spanish SEOSAR/PAZ. In this sense, this thesis proposes to study and analyze the performance of the state-of-the-Art space-borne SAR systems, with modes able to provide Moving Target Indication capabilities (MTI), i.e. moving object detection and estimation. The research will focus on the MTI processing techniques as well as the architecture and/ or configuration of the SAR instrument, setting the limitations of the current systems with MTI capabilities, and proposing efficient solutions for the future missions. Two European projects, to which the Universitat Politècnica de Catalunya provides support, are an excellent framework for the research activities suggested in this thesis. NEWA project proposes a potential European space-borne radar system with MTI capabilities in order to fulfill the upcoming European security policies. This thesis will critically review the state-of-the-Art MTI processing techniques as well as the readiness and maturity level of the developed capabilities. For each one of the techniques a performance analysis will be carried out based on the available technologies, deriving a roadmap and identifying the different technological gaps. In line with this study a simulator tool will be developed in order to validate and evaluate different MTI techniques in the basis of a flexible space-borne radar configuration. The calibration of a SAR system is mandatory for the accurate formation of the SAR images and turns to be critical in the advanced operation modes as MTI. In this sense, the SEOSAR/PAZ project proposes the study and estimation of the radiometric budget. This thesis will also focus on an exhaustive analysis of the radiometric budget considering the current calibration concepts and their possible limitations. In the framework of this project a key point will be the study of the Dual Receive Antenna (DRA) mode, which provides MTI capabilities to the mission. An additional aspect under study is the applicability of the Digital Beamforming on multichannel and/or multistatic radar platforms, which conform potential solutions for the NEWA project with the aim to fully exploit its capability jointly with MTI techniques.

La reincidència penitenciària a Catalunya

L’estudi té per objectiu conèixer la reincidència penitenciària de la població excarcerada de les presons catalanes l’any 1997, fent el seguiment durant 5 anys en tot el territori Espanyol. La població total es composa de 3.898 persones, de les que la mostra estudiada ha estat de 1.555 persones. S’ha treballat amb els expedients informàtics dels interns que composen la mostra, identificats amb codis numèrics per garantir la privacitat de les dades. A part d’actualitzar la taxa de reincidència penitenciària (la última datava de l’any 1994 i es referia a les dades de 1987), l’estudi també descriu e les relacions significatives entre determinades variables individuals i d’historial delictiu i penitenciari, i el fet que es reincideixi o no. També identifica el perfil més comú de les persones reincidents front a les que no ho són. I, finalment, es desenvolupa un model predictiu de la reincidència mitjançant l’aplicació de tècniques d’anàlisi multivariat.

Informality and overeducation in the labor market of a developing country

In this paper, we explore the connection between labor market segmentation in two sectors, a modern protected formal sector and a traditional- unprotected-informal sector, and overeducation in a developing country. Informality is thought to have negative consequences, primarily through poorer working conditions, lack of social security, as well as low levels of productivity throughout the economy. This paper considers an aspect that has not been previously addressed, namely the fact that informality might also affect the way workers match their actual education with that required performing their job. We use micro-data from Colombia to test the relationship between overeducation and informality. Empirical results suggest that, once the endogeneity of employment choice has been accounted for, formal male workers are less likely to be overeducated. Interestingly, the propensity of being overeducated among women does not seem to be closely related to the employment choice.

Bandwidth allocation based on real time calculations using the convolution approach

This paper focuses on one of the methods for bandwidth allocation in an ATM network: the convolution approach. The convolution approach permits an accurate study of the system load in statistical terms by accumulated calculations, since probabilistic results of the bandwidth allocation can be obtained. Nevertheless, the convolution approach has a high cost in terms of calculation and storage requirements. This aspect makes real-time calculations difficult, so many authors do not consider this approach. With the aim of reducing the cost we propose to use the multinomial distribution function: the enhanced convolution approach (ECA). This permits direct computation of the associated probabilities of the instantaneous bandwidth requirements and makes a simple deconvolution process possible. The ECA is used in connection acceptance control, and some results are presented

Two-sided learning in new keynesian models: dynamics, (lack of) convergence and the value of information

This paper investigates the role of learning by private agents and the central bank (two-sided learning) in a New Keynesian framework in which both sides of the economy have asymmetric and imperfect knowledge about the true data generating process. We assume that all agents employ the data that they observe (which may be distinct for different sets of agents) to form beliefs about unknown aspects of the true model of the economy, use their beliefs to decide on actions, and revise these beliefs through a statistical learning algorithm as new information becomes available. We study the short-run dynamics of our model and derive its policy recommendations, particularly with respect to central bank communications. We demonstrate that two-sided learning can generate substantial increases in volatility and persistence, and alter the behavior of the variables in the model in a signifficant way. Our simulations do not converge to a symmetric rational expectations equilibrium and we highlight one source that invalidates the convergence results of Marcet and Sargent (1989). Finally, we identify a novel aspect of central bank communication in models of learning: communication can be harmful if the central bank's model is substantially mis-specified

The Impacts of social networks on immigrants' employment prospect: the spanish case 1997-2007

This paper studies the extent to which social networks influence the employment stability and wages of immigrants in Spain. By doing so, I consider an aspect that has not been previously addressed in the empirical literature, namely the connection between immigrants' social networks and labor market outcomes in Spain. For this purpose, I use micro-data from the National Immigrant Survey carried out in 2007. The analysis is conducted in two stages. First, the impact of social networks on the probability of keeping the first job obtained in Spain is studied through a multinomial logit regression. Second, quantile regressions are used to estimate a wage equation. The empirical results suggest that once the endogeneity problem has been accounted for, immigrants' social networks influence their labor market outcomes. On arrival, immigrants experience a mismatch in the labor market. In addition, different effects of social networks on wages by gender and wage distribution are found. While contacts on arrival and informal job access mechanisms positively influence women's wages, a wage penalty is observed for men.

Role of Particle Shape on the Stress Propagation in Granular Packings

We present an experimental and numerical study on the influence that particle aspect ratio has on the mechanical and structural properties of granular packings. For grains with maximal symmetry (squares), the stress propagation in the packing localizes forming chainlike forces analogous to the ones observed for spherical grains. This scenario can be understood in terms of stochastic models of aggregation and random multiplicative processes. As the grains elongate, the stress propagation is strongly affected. The interparticle normal force distribution tends toward a Gaussian, and, correspondingly, the force chains spread leading to a more uniform stress distribution reminiscent of the hydrostatic profiles known for standard liquids

Assimilació, integració laboral, domini de l'idioma i segregació residencial

La literatura econòmica sobre immigració i mercat de treball ha analitzat dos grans temes. Un és l’efecte que genera la immigració sobre les condicions laborals (ocupació i salaris) dels nadius. L’altre és l’assimilació dels immigrants en el país d’acollida. Aquest projecte s'emmarca en aquesta segona línia de recerca. L’assimilació s’entén com un procés complex en el que un immigrant s’integra completament en el seu país d’acollida en diferents aspectes interrelacionats: l’estatus socioeconòmic, el progrés salarial, el domini de l’idioma o la segregació residencial, entre d'altres. El nostre projecte es centra en l’anàlisi de l’assimilació dels immigrants que han arribat recentment al nostre mercat de treball. Des d'aquesta perspectiva, s'ha analitzat si com a conseqüència de la transferibilitat limitada del capital humà entre països, es produeix o no una degradació ocupacional inicial que porti associada una quantiosa diferència salarial amb els nadius de similars característiques. De fet, com menys transferible sigui el capital humà d'origen, major serà la degradació ocupacional i la consegüent bretxa salarial inicial. També s'ha analitzat de manera més directa quin paper juga la portabilitat del capital humà a l'hora d'explicar el progrés econòmic dels immigrants. L’evidència obtinguda permet concloure que, a mesura que s'amplia el temps de residència al país de destinació, el capital humà es va adaptant als requeriments del mercat laboral del país hoste, especialment a través de l'experiència en el lloc de treball, però també per aprenentatge del nou idioma o fins i tot realització d'estudis. El capital humà així acumulat permet millorar posicions en l'escala ocupacional i augmentar en paral•lel els ingressos, assimilant-los amb el temps als dels nadius d'iguals característiques. Per últim, l’anàlisi del paper de les xarxes socials dels immigrants mostra un efecte positiu sobre la probabilitat de trobar feina però un pitjor emparellament en el mercat de treball.