Iberian universities: a characterisation from ESI rankings

The access to bibliographic and citation databases allows to evaluate scientific performance, and provides useful means of general characterisation. In this paper we investigate the clustering of Iberian universities, resulting from the similarity in the number and specific nature of the scientific disciplines given by the Essential Science Indicators database. A further refining of the analysis, as provided by PCA, clearly reveals the relationship between the universities and the scientific disciplines in the main groups. Similarity between universities is not dictated only by the number of areas in the ranking, but also stems from the nature of the ranked scientific areas and the specific combination in each university.     

Metaheuristic optimization frameworks: a survey and benchmarking

This paper performs an unprecedented comparative study of Metaheuristic optimization frameworks. As criteria for comparison a set of 271 features grouped in 30 characteristics and 6 areas has been selected. These features include the different metaheuristic techniques covered, mechanisms for solution encoding, constraint handling, neighborhood specification, hybridization, parallel and distributed computation, software engineering best practices, documentation and user interface, etc. A metric has been defined for each feature so that the scores obtained by a framework are averaged within each group of features, leading to a final average score for each framework. Out of 33 frameworks ten have been selected from the literature using well-defined filtering criteria, and the results of the comparison are analyzed with the aim of identifying improvement areas and gaps in specific frameworks and the whole set. Generally speaking, a significant lack of support has been found for hyper-heuristics, and parallel and distributed computing capabilities. It is also desirable to have a wider implementation of some Software Engineering best practices. Finally, a wider support for some metaheuristics and hybridization capabilities is needed.     

Fly ash addition in clayey materials to improve the quality of solid bricks

The technical quality of two compositionally different groups of solid bricks fired between 800 and 1000 °C was evaluated. Five weight percentage of fly ash was added to both groups and they were compared with similar bricks with no added fly ash.The textures of the bricks with fly ash were very similar to the textures of those without it, except that the samples with the additive contained spherical fly ash particles with diameters ranging from 0.1 to 10 μm. These particles led to a reduction in the density of the bricks and a substantial improvement in their durability, with less decay being caused by salt crystallization in the pores. This is because fly ash causes a reduction in the number of micropores, the pores that make porous materials most vulnerable to salt-induced decay. Use of this additive could have practical implications as a means of recycling and for achieving cost savings in brick production.     

Towards occupant-centric simulation-aided building design: a case study

ABSTRACT

This paper aims at illustrating the importance of occupant modelling for decision-making during the building design process. It identifies the energy implications of conventional ways of modelling occupants for the design of office buildings. Furthermore, it presents a step towards bridging the gap between the research efforts and conventional practices within the field of building performance simulation (BPS) aided design. The paper first describes occupant-related assumptions that were made during the design process of a case study office building, obtained via stakeholder interviews. Then, the impact of these assumptions on the design decisions is examined through a simulation-based investigation. The stakeholder interviews revealed that professionals from each design discipline made significantly different assumptions about occupants. The simulation results showed that assumptions about occupants and their behaviour impacted predicted energy savings of some design decisions by a factor of five or more.     

Form birefringence and turbidity of polystyrene/poly(methyl methacrylate) blends in slit dies and planar contractions

The birefringence and turbidity of a polystyrene/poly(methyl methacrylate) (PMMA) blend, with the concentration of the PMMA dispersed phase ranging up to 1%, were measured in both a slit channel with a constant cross section and a planar hyperbolic contraction/expansion (8:1:8). The measurements were performed by the attachment of a modular rheo‐optical die to a twin‐screw extruder. The optical arrangement had a red light‐emitting diode as the source and two photoresistors, with one of them measuring the turbidity and the other one measuring the transmitted intensity between cross‐polarizers. The experimental procedure consisted of the stopping of the extruder feeding, while the screw rotation was kept constant. Because the form birefringence could be associated with the shape of the droplets, these measurements were used to infer information about the PMMA droplet deformation and breakup. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44066.     

Uncalibrated visual servoing using the fundamental matrix

This paper describes a new algorithm for visual control of an uncalibrated 3 DOF joint system, using two weakly calibrated fixed cameras. The algorithm estimates on-line the Image Jacobian, a matrix which linearly relates joint velocity and image feature velocity. In our experiments we prove that by using the fundamental matrix, robustness of the estimation in the presence of noise is significantly increased with respect to already existing algorithms in specialized literature.     

Influence of network dynamics on the spread of sexually transmitted diseases

Network epidemiology often assumes that the relationships defining the social network of a population are static. The dynamics of relationships is only taken indirectly into account by assuming that the relevant information to study epidemic spread is encoded in the network obtained, by considering numbers of partners accumulated over periods of time roughly proportional to the infectious period of the disease. On the other hand, models explicitly including social dynamics are often too schematic to provide a reasonable representation of a real population, or so detailed that no general conclusions can be drawn from them. Here, we present a model of social dynamics that is general enough so its parameters can be obtained by fitting data from surveys about sexual behaviour, but that can still be studied analytically, using mean-field techniques. This allows us to obtain some general results about epidemic spreading. We show that using accumulated network data to estimate the static epidemic threshold lead to a significant underestimation of that threshold. We also show that, for a dynamic network, the relative epidemic threshold is an increasing function of the infectious period of the disease, implying that the static value is a lower bound to the real threshold. A practical example is given of how to apply the model to the study of a real population.