Improving Third-Party Relaying for LTE-A: A Realistic Simulation Approach

In this article we propose solutions to diverse conflicts that result from the deployment of the (still immature) relay node (RN) technology in LTE-A networks. These conflicts and their possible solutions have been observed by implementing standard-compliant relay functionalities on the Vienna simulator. As an original experimental approach, we model realistic RN operation, taking into account that transmitters are not active all the time due to half-duplex RN operation. We have rearranged existing elements in the simulator in a manner that emulates RN behavior, rather than implementing a standalone brand-new component for the simulator. We also study analytically some of the issues observed in the interaction between the network and the RNs, to draw conclusions beyond simulation observation. The main observations of this paper are that: $i$) Additional time-varying interference management steps are needed, because the LTE-A standard employs a fixed time division between eNB-RN and RN-UE transmissions (typical relay capacity or throughput research models balance them optimally, which is unrealistic nowadays); $ii$) There is a trade-off between the time-division constraints of relaying and multi-user diversity; the stricter the constraints on relay scheduling are, the less flexibility schedulers have to exploit channel variation; and $iii$) Thee standard contains a variety of parameters for relaying configuration, but not all cases of interest are covered.Comment: 17 one-column pages, 9 figures, accepted for publication in IEEE ICC 2014 MW

DOES SERVICE QUALITY MATTER IN MEASURING PERFORMANCE OF WATER UTILITIES?

Quality is a dimension of water services that has been repeatedly omitted in the study of performance of water utilities. In this paper, we make use of Data Envelopment Analysis techniques (DEA) to compute both conventional quantity-based and quality-adjusted indicators of technical efficiency for a sample of Spanish water utilities. The key assumptions are that a lack of quality (bad quality) can be regarded as a bad output, and the existence of a trade-off between quantity and quality. Our main results indicate that quality matters in measuring technical performance, the difference between conventional and quality-adjusted evaluations representing the opportunity cost of maintaining quality. Averages and distribution functions significantly differ between both assessments of performance, although water utilities do not seem to rank differently.water utilities; quality; Data Envelopment Analysis.

Can we be satisfied with our football team? Evidence from spanish professional football.

This paper assesses the sporting performance of Spanish professional football teams at competition level, namely, League, King’s Cup and European competitions (Champions League and UEFA Cup). Then, the gap between the result obtained by a team in a given competition and that expected according to its potential is used as a proxy of the degree of satisfaction that fans should feel: the narrower the gap the greater the level of satisfaction. Regarding methodology, Data Envelopment Analysis techniques and directional distance functions are used. Results reveal that most teams perform rather differently across competitions, the lower average performance corresponding to the King’s CupSpanish football League; specific-competition performance; Data Envelopment Analysis.

The importance of time in referee home bias due to social pressure. Evidence from Spanish football

This paper analyses referee home bias due to social pressure with data from the matches played in the First Division of the Spanish football league between the 2002/03 and 2009/10 seasons. Finally, our main conclusion is that the time the referee has to make a decision does affect the final outcome; while there is no referee home bias when a free kick is awarded, in the case of booking players, when the referee has more time to make a decision, social pressure can influence the final outcome in favour of the home team.Social pressure; crowd effect; referee home bias; sports economics.

A new geometrical method for 3D evaluation of non-rigid registration methods for radiotherapy in prostate cancer

Three-dimensional conformal radiotherapy aims at delivering a high dose of radiation to the tumour, while sparing the surrounding normal tissue to a maximum extent. Image registration is an essential tool for monitoring radiation therapies, since allows morphological comparisons in presence of anatomic variations. The evaluation of non-rigid registration methods is very complicated owe to the absence of a known pointwise correspondence. The use of analysis of variations in target volume delineations has been proposed in the past for the evaluation of non-rigid registration methods. Delineation of the target volume is usually accomplished by outlining the contour of the volume in each separate tomographic slice. In the studies of reference, the 3D surface is rendered from the contours by means of a Delauney triangulation. This geometrical method only works correctly for convex structures. However the volumes involved on pelvic anatomy, such as bladder or prostate including the seminal vesicles, have relevant concavities that introduce a huge error in the evaluation. A new geometrical method for the evaluation of convex-concave target volumes delineation is proposed

Colonization and dispersal patterns of the invasive American brine shrimp Artemia franciscana (Branchiopoda: Anostraca) in the Mediterranean region

Cysts of the brine shrimp Artemia franciscana are harvested from the Great Salt Lake (GSL) and San Francisco Bay (SFB) saltworks in the USA, and marketed worldwide to provide live food for aquaculture. This species has become invasive across several countries. We investigated (1) if the introduced populations in the Mediterranean region could have originated from these USA populations, (2) how the genetic diversity of Mediterranean compares to that at GSL and SFB, and (3) if genetic patterns in the Mediterranean can shed light on colonization routes. We sequenced a fragment of the cytochrome c oxidase subunit I and screened microsatellites loci from Mediterranean populations and the two putative USA sources. Haplotypes from Mediterranean populations were identical or closely related to those from SFB and GSL, and not related to other available American populations. Microsatellite analyses showed a reduced population diversity for most Mediterranean populations suggesting bottleneck effects, but few populations were showing similar or higher genetic diversity than native ones, which are likely to be admixed from both GSL and SFB because of multiple introductions. Results suggest natural dispersal, potentially via flamingos, between two Spanish populations. Our analyses show that all invaded populations could have originated from those commercialized USA populations. © 2013 Springer Science+Business Media Dordrecht

Fractional and scaled Brownian motion on the sphere: The effects of long-time correlations on navigation strategies

We analyze long-time correlated Brownian motion and scaled Brownian motion on the surface of the two dimensional sphere $\mathbb{S}^{2}$. Due to the geometric effects induced by the $\mathbb{S}^{2}$ curvature, such correlations collude with specific dynamics (\emph{navigation strategies}) on the manifold topology to originate rich transport properties. We focus our study to two classes of navigation strategies: One induced by the specific set of coordinates chosen for $\mathbb{S}^2$ which defines a fixed frame of reference; in particular, we chose the basis induced by spherical coordinates. We find that contrary to what occurs in the absence of correlations non-equilibrium stationary distributions are attained. We elucidate an analogy of our results with those observed of fractional Brownian motion in confined by reflecting walls in one and two dimensions. In contrast, when the navigation strategy chosen corresponds to a frame of reference moving with the particle as does the Frenet-Serret system, then the equilibrium uniform distribution on the sphere is attained. In both cases, the relaxation times towards the stationary distribution depend on the particular value of the Hurst parameter. We show that scaled Brownian motion on $\mathbb{S}^2$ is independent of the navigation strategy and we find a good agreement between the analytical calculations obtained from the solution of a time-dependent diffusion equation on $\mathbb{S}^{2}$ and the numerical results obtained from our method to generate ensemble of trajectories.Comment: The statistics of Fractional Brownian motion and of scaled Brownian motion are analyzed when motion is constrained to surface of a spher

The difficult didactic transposition. A comparative study of the construction of social stereotypes from historiography to the classroom (Spain-France)

El objetivo de este trabajo es analizar la difícil transposición didáctica desde la historiografía al aula a través de una temática concreta: el mundo rural en la Edad Moderna en España y Francia. Para conseguir este objetivo se ha partido del estudio de la construcción historiográfica sobre el campesinado y el mundo rural en las principales revistas de investigación de esta temática. Posteriormente se ha comprobado la transmisión de este conocimiento en las aulas a través de las propuestas curriculares. Finalmente se ha analizado la percepción del alumnado sobre los estereotipos sociales ligados a esta temática. Los resultados muestran un desequilibrio importante entre la representación del mundo urbano y el mundo rural, fruto de la pervivencia de la teoría de la modernización en las explicaciones históricas.The objective of this paper is to analyze the difficult didactic transposition from the historiography to the classroom through a concrete issue: the rural world in the Early Modern Age in Spain and France. To achieve this objective, this paper start with the study of the historiographical construction of the peasantry and the rural world in the most representative journals. Second it has been verified the transmission of this knowledge in the classrooms through the curricular proposals. Finally we have analyzed the student's perception of the social stereotypes related to this subject. The results show a significant imbalance between the representation of the urban world and the rural world, consequence of the survival of the theory of modernization in historical explanations.Este trabajo es resultado del proyecto de investigación "Familia, desigualdad social y cambio generacional en la España centro-meridional, ss. XVI-XIX" (HAR2013-48901-C6-6-R) y EDU2015-65621-C3-2-R “La evaluación de las competencias y el desarrollo de capacidades cognitivas sobre historia en Educación Secundaria Obligatoria”, financiados ambos por el Ministerio de Economía y Competitividad y los fondos FEDER