A simulation-based algorithm for solving the resource-assignment problem in satellite telecommunication networks

This paper proposes an heuristic for the scheduling of capacity requests and the periodic assignment of radio resources in geostationary (GEO) satellite networks with star topology, using the Demand Assigned Multiple Access (DAMA) protocol in the link layer, and Multi-Frequency Time Division Multiple Access (MF-TDMA) and Adaptive Coding and Modulation (ACM) in the physical layer.

Anàlisi d'usabilitat de les cooperatives de fruita i oli de Lleida

En aquest projecte, es realitza un anàlisi d'usabilitat de les pàgines webs de cooperatives de fruita i oli de Lleida. Per mitjà de dues tècniques, l'anàlisi de les pàgines principals i l'avaluació heurística, es detecten els problemes d'usabilitat més comuns en pàgines d'aquest sector i es donen unes recomanacions de millora.

Diseño e implementación de un gestor para realizar evaluaciones heurísticas

El trabajo consiste en el desarrollo de una aplicación que permita gestionar evaluaciones heurísticas de diferentes proyectos. Debe almacenar la información del proyecto y de los evaluadores, la heurística empleada, la evaluación y los resultados de la misma.

Anàlisi de la usabilitat del portal web del grup Segre

Analitza la usabilitat de la web del diari Segre, l'aplicació e-Segre i la plana web Cercle. Per realitzar aquest anàlisi s'han utilitzat dues tècniques: realització d'una avaluació heurística amb experts i realització de tests d'usuaris mitjançant l'Eye tracking. Tots aquests tests i avaluacions s'han dut a terme per poder arribar a una conclusió final.

Comparison of Work Scheduling Using Constraint Programming or Auctions

Business processes designers take into account the resources that the processes would need, but, due to the variable cost of certain parameters (like energy) or other circumstances, this scheduling must be done when business process enactment. In this report we formalize the energy aware resource cost, including time and usage dependent rates. We also present a constraint programming approach and an auction-based approach to solve the mentioned problem including a comparison of them and a comparison of the proposed algorithms for solving them

Propuesta para incorporar evaluación y pruebas de usabilidad dentro de un proceso de desarrollo de software

Usability is critical to consider an interactive software system successful. Usability testing and evaluation during product development have gained wide acceptance as a strategy to improve product quality. Early introduction of usability perspectives in a product is very important in order to provide a clear visibility of the quality aspects not only for the developers, but also for the testing users as well. However, usability evaluation and testing are not commonly taken into consideration as an essential element of the software development process. Then, this paper exposes a proposal to introduce usability evaluation and testing within a software development through reuse of software artifacts. Additionally, it suggests the introduction of an auditor within the classification of actors for usability tests. It also proposes an improvement of checklists used for heuristics evaluation, adding quantitative and qualitative aspects to them

Women's work histories in Italy: education as investment in reconciliation and legitimacy?

Within pre-enlargement Europe, Italy records one of the widest employment rate gaps between highly and poorly educated women, as well one of the largest differences in the share, among working women, of public sector employment. Building on these stylized facts and using the Longitudinal Survey of Italian Households (ILFI), we investigate the working trajectories of three cohorts of Italian women born between 1935 and 1964 and observed from their first job until they are in their forties. We use mainly, but not exclusively, event history analysis in order to identify the main factors that influence entry into and exit from paid work over the life course. Our results suggest that in the Italian context, where employment protection policies have also been used as surrogate measures to favour reconciliation between family and work, and where traditional gender norms still persist, education is so important for women's employment decisions because it represents an investment in 'reconciliation' and 'work legitimacy' over and above investment in human capital.

Ens falla la intuïció?

Aquest treball pretén analitzar l’ús dels procediments heurístics i els seus biaixos. Per això, hemrealitzat un estudi entre dues poblacions: 4rt d’Humanitats i 4rt d’ECO/ADE. Per dur a termeaquesta comparació hem realitzat una enquesta que pretenia detectar els biaixos. Amb elsresultats hem pogut comprovar que efectivament hi ha diferències significatives entre els dosgrups. Concretament, els estudiants d’ECO/ADE cometen menys biaixos.

Empirical studies of cloud effects on UV radiation: A review

The interest in solar ultraviolet (UV) radiation from the scientific community and the general population has risen significantly in recent years because of the link between increased UV levels at the Earth's surface and depletion of ozone in the stratosphere. As a consequence of recent research, UV radiation climatologies have been developed, and effects of some atmospheric constituents (such as ozone or aerosols) have been studied broadly. Correspondingly, there are well-established relationships between, for example, total ozone column and UV radiation levels at the Earth's surface. Effects of clouds, however, are not so well described, given the intrinsic difficulties in properly describing cloud characteristics. Nevertheless, the effect of clouds cannot be neglected, and the variability that clouds induce on UV radiation is particularly significant when short timescales are involved. In this review we show, summarize, and compare several works that deal with the effect of clouds on UV radiation. Specifically, works reviewed here approach the issue from the empirical point of view: Some relationship between measured UV radiation in cloudy conditions and cloud-related information is given in each work. Basically, there are two groups of methods: techniques that are based on observations of cloudiness (either from human observers or by using devices such as sky cameras) and techniques that use measurements of broadband solar radiation as a surrogate for cloud observations. Some techniques combine both types of information. Comparison of results from different works is addressed through using the cloud modification factor (CMF) defined as the ratio between measured UV radiation in a cloudy sky and calculated radiation for a cloudless sky. Typical CMF values for overcast skies range from 0.3 to 0.7, depending both on cloud type and characteristics. Despite this large dispersion of values corresponding to the same cloud cover, it is clear that the cloud effect on UV radiation is 15–45% lower than the cloud effect on total solar radiation. The cloud effect is usually a reducing effect, but a significant number of works report an enhancement effect (that is increased UV radiation levels at the surface) due to the presence of clouds. The review concludes with some recommendations for future studies aimed to further analyze the cloud effects on UV radiation

Theoretical study of elastic electron scattering off stable and exotic nuclei

Results for elastic electron scattering by nuclei, calculated with charge densities of Skyrme forces and covariant effective Lagrangians that accurately describe nuclear ground states, are compared against experiment in stable isotopes. Dirac partial-wave calculations are performed with an adapted version of the ELSEPA package. Motivated by the fact that studies of electron scattering off exotic nuclei are intended in future facilities in the commissioned GSI and RIKEN upgrades, we survey the theoretical predictions from neutron-deficient to neutron-rich isotopes in the tin and calcium isotopic chains. The charge densities of a covariant interaction that describes the low-energy electromagnetic structure of the nucleon within the Lagrangian of the theory are used to this end. The study is restricted to medium- and heavy-mass nuclei because the charge densities are computed in mean-field approach. Because the experimental analysis of scattering data commonly involves parameterized charge densities, as a surrogate exercise for the yet unexplored exotic nuclei, we fit our calculated mean-field densities with Helm model distributions. This procedure turns out to be helpful to study the neutron-number variation of the scattering observables and allows us to identify correlations of potential interest among some of these observables within the isotopic chains.

Model-Free Reconstruction of Excitatory Neuronal Connectivity from Calcium Imaging Signals

A systematic assessment of global neural network connectivity through direct electrophysiological assays has remained technically infeasible, even in simpler systems like dissociated neuronal cultures. We introduce an improved algorithmic approach based on Transfer Entropy to reconstruct structural connectivity from network activity monitored through calcium imaging. We focus in this study on the inference of excitatory synaptic links. Based on information theory, our method requires no prior assumptions on the statistics of neuronal firing and neuronal connections. The performance of our algorithm is benchmarked on surrogate time series of calcium fluorescence generated by the simulated dynamics of a network with known ground-truth topology. We find that the functional network topology revealed by Transfer Entropy depends qualitatively on the time-dependent dynamic state of the network (bursting or non-bursting). Thus by conditioning with respect to the global mean activity, we improve the performance of our method. This allows us to focus the analysis to specific dynamical regimes of the network in which the inferred functional connectivity is shaped by monosynaptic excitatory connections, rather than by collective synchrony. Our method can discriminate between actual causal influences between neurons and spurious non-causal correlations due to light scattering artifacts, which inherently affect the quality of fluorescence imaging. Compared to other reconstruction strategies such as cross-correlation or Granger Causality methods, our method based on improved Transfer Entropy is remarkably more accurate. In particular, it provides a good estimation of the excitatory network clustering coefficient, allowing for discrimination between weakly and strongly clustered topologies. Finally, we demonstrate the applicability of our method to analyses of real recordings of in vitro disinhibited cortical cultures where we suggest that excitatory connections are characterized by an elevated level of clustering compared to a random graph (although not extreme) and can be markedly non-local.

Esquemas de conducta, procesos de pensamiento, actos de habla

La investigación psicológica de los procesos cognitivos y su configuración especifica a partir del lenguaje se encuentra en el límite de la pregunta filosófica acerca de la relación lenguaje-pensamiento-realidad y de la preocupación epistemológica por esclarecer la interconexión de las teorias científicas y los datos observacionales o experimentales, la lógica interna del proceso científic0 y las posibilidades de elaboración de una heurística que facilite el establecimiento de patrones de descubrimiento. Aunque conviene delimitar los distintos campos, la perspectiva global de esta problemática permite fecundar nuevos proyectos de estudio. La Escuela de Würzburg nos ofrece un buen ejemplo de investigaciones diversas sobre estos temas, en las que se procede unas veces intensivamente (de forma muy especifica) y otras veces de manera extensiva. En el articulo se da una información general de 10s principales autores de la Escuela, se entra en la consideración de las tesis centrales que Külpe expuso en su libro Die Realisierung y se destaca la importancia concedida a 10s trabajos de Karl Bühler por parte de teóricos de la ciencia como Popper y Hans Albert.

Dynamics of flow: a nonlinear perspective

The aims of this study are to consider the experience of flow from a nonlinear dynamics perspective. The processes and temporal nature of intrinsic motivation and flow, would suggest that flow experiences fluctuate over time in a dynamical fashion. Thus it can be argued that the potential for chaos is strong. The sample was composed of 20 employees (both full and part time) recruited from a number of different organizations and work backgrounds. The Experience Sampling Method (ESM) was used for data collection. Once obtained the temporal series, they were subjected to various analyses proper to the com- plexity theory (Visual Recurrence Analysis and Surrogate Data Analysis). Results showed that in 80% of the cases, flow presented a chaotic dynamic, in that, flow experiences delineated a complex dynamic whose patterns of change were not easy to predict. Implications of the study, its limitations and future research are discussed.

Usabilitat dels sistemes operatius en smartphones (Android vs iOS)

Aquest treball es portarà a terme realitzant una avaluació heurística dels sistmes operatius seleccionats i de les seves aplicacions, un test d'usabilitat i un anàlisi de l'organització de les funcions mitjançant un card sorting on-line.

The Price of luck

We find that the vast majority of students taking an advanced undergraduate finance course show a preference for luck in a classroom experiment. In Phase I of the experiment part of the students, group A, were asked to guess a coin toss five times in a row. In Phase II the rest of the students, group B, were given 10 EUR to bet on some of the Group A students taking a second go at guessing a sequence of five coin tosses (Phase III). Group B students’ bets were by default allocated to the worse performing student in Phase I. Switching to better performing Group A students was costly. A total of 23 out of 28 students were willing to pay for switching and thus showed a preference for luck.