New possibilistic method for discovering linear local behavior using hyper-Gaussian distributed membership function

This paper presents a method to find a model of a system based on the integration of a set of local models. Mainly, properties are sought for the local models: independence of clusters and interpretability of their validity. This has been achieved through the introduction of a possibilistic clustering for the first property and a pre-fixed shape of the membership functions for the second one. A new cost index for the clustering optimization problem has been defined consisting of two terms: one for global error and another for local errors. By giving higher importance to the local errors term, local models valid regionally can be found. To avoid local optima and numerical issues, the parameters of the models are found using global optimization. This new method has been applied to several data sets, and results show how the desired characteristics can be achieved in the resulting models.     

Thermal,hydrolytic, anticorrosive,and tribological properties of alkyd‐silicone hyperbranched resins with high solid content

Novel alkyd hyperbranched resins (AHBRs) modified with a Z‐6018 silicone (a polysiloxane intermediate) and with high solid content were synthesized by etherification reaction using an acid catalyst. Different molar ratios of AHBR to silicone were used. Structural, thermal, hydrolytic, anticorrosive, and tribological properties were studied using infrared (IR) analysis, nuclear magnetic resonance (NMR), vapor pressure osmometry (VPO), thermogravimetric analysis (TGA), acid value, electrochemical impedance spectroscopy (EIS), and pin‐on‐disk friction. IR and NMR provide evidence of grafting of the silicone on AHBR; the efficiency of grafting was quantified by TGA. Thermal stability was studied also by acid value analysis. Grafting increases the number average molecular mass, enhances thermal stability, and improves significantly hydrolytic stability. Corrosion resistance on steel is improved by two orders of magnitude, hence our modified materials can be used as highly effective anticorrosion coatings. Grafting lowers dynamic friction dramatically, more so at higher concentrations of silicone. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A Comparison of Head Pose and Deictic Pointing Interaction Methods for Smart Environments

Pointing is one of the more meaningful gestures in human expression. In this article, deictic and head pose pointing methods are evaluated as interaction means, with the objective of comparing their efficiency and delivered comfort, usability, and user experience to apply them to the deployment of services in smart spaces. Standard tools and questionnaires are applied in a user study with 20 individuals who have tried a Kinect V2-enabled pointing system to a) complete a multidirectional International Organization for Standardization (ISO) 9241-9 pointing task and b) test a service to command smart objects. The results show that both deictic and head pose interaction perform in a similar way, providing a throughput of 2.14 and 2.04 bits/s, respectively (comparable to joysticks or touchpads in equivalent ISO tasks). The system being quite robust to the user position in the Kinect coverage area, target size influences performance, but also learnability and the overall response when cursor visual cues are not available. From comfort, usability, and user experience responses, it can be said that deictic is perceived to perform better than head pose in terms of accuracy, efficiency, and organization, although head pose is preferred for its speed.     

Collective foraging in heterogeneous landscapes

Animals foraging alone are hypothesized to optimize the encounter rates with resources through Lévy walks. However, the issue of how the interactions between multiple foragers influence their search efficiency is still not completely understood. To address this, we consider a model to study the optimal strategy for a group of foragers searching for targets distributed heterogeneously. In our model, foragers move on a square lattice containing immobile but regenerative targets. At any instant, a forager is able to detect only those targets that happen to be in the same site. However, we allow the foragers to have information about the state of other foragers. A forager who has not detected any target walks towards the nearest location, where another forager has detected a target, with a probability exp(−αd), where d is the distance between the foragers and α is a parameter characterizing the propensity of the foragers to aggregate. The model reveals that neither overcrowding (α → 0) nor independent searching (α → ∞) is beneficial for the foragers. For a patchy distribution of targets, the efficiency is maximum for intermediate values of α. In addition, in the limit α → 0, the length of the walks can become scale-free.     

Changes in bioactive compounds and antioxidant activity during convective drying of murta (Ugni molinae T.) berries

Murta (Ugni molinae T.) berries were air‐dried at five temperatures (40, 50, 60, 70 and 80 °C), and the changes in β‐carotene, phenolic acids, total phenolic and flavonoid contents and antioxidant capacities (DPPH and ORAC) were investigated. The berries showed a high content of β‐carotene, which decreased during drying temperature between 40 °C and 80 °C. Free and bound phenolic acids were also determined, showing gallic acid to be the prevalent phenolic acid. Total phenolic and flavonoid contents in the dried berries showed a higher decrease at lower temperature due to longer drying time. The radical‐scavenging activity also showed higher antioxidant activity at higher drying temperatures (70–80 °C) than at lower drying temperatures (40–50 °C). Total phenolic content (TPC) and flavonoids showed good correlation with antioxidant capacity. Murta berries proved to be an excellent source of antioxidants and bioactive compounds and are therefore a potential ingredient for new functional food products.     

The applied pretreatment (blanching,ascorbic acid) at the manufacture process affects the quality of nectarine purée processed by hydrostatic high pressure

A nectarine purée was manufactured with different pretreatments (thermal blanching or ascorbic acid – AA – addition), and then, the purée was processed by high‐pressure treatment to evaluate the effect of the initial manufacture conditions in the stability of the processed purées. A thermal treatment was also carried out to compare the effect with the high‐pressure processing (HPP). All applied processes were effective to ensure the microbiological safety of the purées. However, the pretreatment (thermal blanching or AA addition) applied during the manufacture affected the final quality of the processed purées. Initially, the AA addition had a protective effect on colour degradation during the manufacture of the purées; however, when these purées were treated by HPP showed less colour stability during storage, lower bioactive compounds content, and antioxidant activity. In contrast, purées with an initial thermal blanching maintained better the quality after HPP and during storage.     

Google Scholar Metrics evolution: an analysis according to languages

In November 2012 the Google Scholar Metrics (GSM) journal rankings were updated, making it possible to compare bibliometric indicators in the ten languages indexed—and their stability—with the April 2012 version. The h-index and h-5 median of 1,000 journals were analysed, comparing their averages, maximum and minimum values and the correlation coefficient within rankings. The bibliometric figures grew significantly. In just seven and a half months the h-index of the journals increased by 15 % and the median h-index by 17 %. This growth was observed for all the bibliometric indicators analysed and for practically every journal. However, we found significant differences in growth rates depending on the language in which the journal is published. Moreover, the journal rankings seem to be stable between April and November, reinforcing the credibility of the data held by Google Scholar and the reliability of the GSM journal rankings, despite the uncontrolled growth of Google Scholar. Based on the findings of this study we suggest, firstly, that Google should upgrade its rankings at least semi-annually and, secondly, that the results should be displayed in each ranking proportionally to the number of journals indexed by language.     

Speeding-up homography estimation in mobile devices

A critical problem faced by computer vision on mobile devices is reducing the computational cost of algorithms and avoiding visual stalls. In this paper, we introduce a procedure for reducing the number of samples required for fitting a homography to a set of noisy correspondences using a random sampling method. This is achieved by means of a geometric constraint that detects invalid minimal sets. In the experiments conducted, we show that this constraint not only reduces the number of random samples at a negligible computational cost but also balances the processor workload over time preventing visual stalls. In extreme situations of very large outlier proportion and noise level, it reduces in about one order of magnitude the number of required random samples.     

An information based feedback control for audio-motor binaural localization

In static scenarios, binaural sound localization is fundamentally limited by front-back ambiguity and distance non-observability. Over the past few years, “active” schemes have been shown to overcome these shortcomings, by combining spatial binaural cues with the motor commands of the sensor. In this context, given a Gaussian prior on the relative position to a source, this paper determines an admissible motion of a binaural head which leads, on average, to the one-step-ahead most informative audio-motor localization. To this aim, a constrained optimization problem is set up, which consists in maximizing the entropy of the next predicted measurement probability density function over a cylindric admissible set. The method is appraised through geometrical arguments, and validated in simulations and on real-life robotic experiments.