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61.
Cristina Manresa-Yee Javier Varona Francisco J. Perales Iosune Salinas 《Universal Access in the Information Society》2014,13(4):471-482
This work focuses on camera-based systems that are designed for mouse replacement. Usually, these interfaces are based on computer vision techniques that capture the user’s face or head movements and are specifically designed for users with disabilities. The work identifies and reviews the key factors of these interfaces based on the lessons learnt by the authors’ experience and by a comprehensive analysis of the literature to describe the specific points to consider in their design. These factors are as follows: user features to track, initial user detection (calibration), position mapping, feedback, error recovery, event execution, profiles and ergonomics of the system. The work compiles the solutions offered by different systems to help new designers avoid problems already discussed by the others. 相似文献
62.
Rgia Maria Cordeiro Brito Alzir Azevedo Batista Javier Ellena Eduardo E. Castellano Izaura Cirino Nogueira Digenes Luiz Gonzaga de Frana Lopes Jackson Rodrigues de Sousa Ícaro de Sousa Moreira 《Inorganic chemistry communications》2007,10(12):1515-1517
The cis-[Ru(dppb)(Me-bipy)(NCS)2], dppb = 1,4-bis (diphenylphosphino)butane, Me-bipy = 4,4′-dimethyl-2,2′-bipyridine, and NCS = thiocyanate, was synthesized and characterized by spectroscopic and electrochemical techniques and its structure was determined by crystal X-ray analysis. The crystal structure reveals that the coordination geometry around the Ru(II) center is distorted octahedron where two molecules of thiocyanate are bonded to the ruthenium through nitrogen atom in cis orientation. The half-wave formal potential value E1/2 = 0.8 V (versus Ag/AgCl) observed is considerable higher than that for the cis-[RuCl2(dppb)(Me-bipy)] complex, E1/2 = 0.6 V (versus Ag/AgCl), well illustrating the strong π-acceptor effect the NCS ligand toward the backbonding interaction with the Ru(II) metal center. The MLCT absorption bands of the thiocyanate complex present a higher molar absorptivity (about 12%) compared with the cis-[RuCl2(dppb)(Me-bipy)] complex, in the same experimental conditions. These properties make the complex potentially promising for the photosensitization process. 相似文献
63.
Andres T Aguayo Ana G Gayubo Ana M Tarrío Alaitz Atutxa Javier Bilbao 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(2):211-216
With the aim of determining the possibilities of directly upgrading the liquid obtained from carbohydrate fermentation, the effect of operating conditions (temperature, space time, water content in the feed) has been studied in the catalytic transformation of aqueous ethanol into hydrocarbons on an HZSM‐5 zeolite in an isothermal fixed bed reactor. Special attention has been paid to the effect of water content on the yield, product distribution and catalyst deactivation. Although deactivation by coke decreases as the water content is increased, this content must be limited at 450 °C and higher temperatures in order to avoid irreversible deactivation of the catalyst by dealumination. © 2002 Society of Chemical Industry 相似文献
64.
Transient isotopic studies in the temporal analysis of products (TAP) reactor evidenced the importance of the lifetime of oxygen species generated upon N2O decomposition on extraframework iron sites of Fe-silicalite for methane oxidation at 723 K. Fe-silicalite effectively activates CH4 when N2O and CH4 are pulsed together in the reactor. However, these oxygen species gradually become inactive for methane oxidation as the time delay between the N2O and CH4 pulses is increased from 0 to 2 s. 相似文献
65.
Javier Prez-Ramírez 《Applied catalysis. B, Environmental》2007,70(1-4):31-35
European authorities consider that N2O emissions from nitric acid plants can be reduced to a large extent at a relatively low cost. Two regulation approaches can have major implications for the fertilizer industry in Europe. The EU integrated pollution prevention and control (IPPC) directive will be effective from October 2007 for existing plants. In this, emission permits will be based on best available techniques (BAT). Additionally, the EU commission will shortly consider whether the emission trading directive should be applicable to cover other greenhouse gases besides CO2. This paper discusses advantages and drawbacks of these approaches, with emphasis on how emission trading with N2O can be turned into a win–win situation both for European governments and for the fertilizer industry. 相似文献
66.
In this study, microcrystalline cellulose (MCC) was chemically modified with 3-(aminopropyl)triethoxysilane and added to epoxy to improve chemical, thermal and dynamic-mechanical characteristics of the composites. The composites were manufactured aided by sonication with 1.0%, 2.5%, or 5.0% wt/wt of untreated MCC or amino-functionalized MCC (MCC-Si). The epoxy/MCC-Si composites showed a decrease in the ─OH band by Fourier-transform infrared spectroscopy, and X-ray diffraction analysis indicated better dispersion. The incorporation of MCC-Si in epoxy resin decreased the heat of reaction, increased activation energy values (Ea) and pre-exponential factor (A), and did not affect thermal degradation. All conversion degree (α) versus temperature curves for the composites showed a sigmoidal shape. MCC-Si composites showed better dynamic-mechanical properties than the MCC counterparts, and the functionalization effect was evidenced in storage modulus (E') and loss modulus (E"). At 2.5% wt/wt of MCC-Si content an increase of 119% in E' at the glassy region, 127% in E' at the rubbery region and 173% in E" was observed compared to the neat resin, whereas the Tg barely changed among samples. Good adhesion between the amino-functionalized MCC and the epoxy matrix was observed at the fracture surface, evidencing that surface modification of MCC improves their chemical interaction. 相似文献
67.
Javier Arellano-Verdejo Enrique Alba Salvador Godoy-Calderon 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2016,20(3):895-905
Clustering algorithms, a fundamental base for data mining procedures and learning techniques, suffer from the lack of efficient methods for determining the optimal number of clusters to be found in an arbitrary dataset. The few methods existing in the literature always use some sort of evolutionary algorithm having a cluster validation index as its objective function. In this article, a new evolutionary algorithm, based on a hybrid model of global and local heuristic search, is proposed for the same task, and some experimentation is done with different datasets and indexes. Due to its design, independent of any clustering procedure, it is applicable to virtually any clustering method like the widely used \(k\)-means algorithm. Moreover, the use of non-parametric statistical tests over the experimental results, clearly show the proposed algorithm to be more efficient than other evolutionary algorithms currently used for the same task. 相似文献
68.
69.
Beatriz Pariente-Martinez Martin Gonzalez-Rodriguez Daniel Fernandez-Lanvin Javier De Andres-Suarez 《Universal Access in the Information Society》2016,15(2):237-247
The influence of aging on computer interaction has been widely analyzed in human–computer interaction research literature. Despite this, there are no age-based user maps that could support the user-interface customization. Studying the specific needs and constraints of these groups is crucial in order to adapt a user interface to the user’s interaction requirements. This work studies the performance of a sample of participants on three different basic tasks (pointing, dragging and dropping, and text selection) and the influence of age for each of them. It is concluded that this influence differs between specific activities. A group profile map that can support automatic classification in the future has been obtained. 相似文献
70.
Xavier Suau Javier Ruiz-Hidalgo Josep R. Casas 《Computer Vision and Image Understanding》2013,117(3):281-288
End-effectors are usually related to the location of limbs, and their reliable detection enables robust body tracking as well as accurate pose estimation. Recent innovation in depth cameras has re-stated the pose estimation problem. We focus on the information provided by these sensors, for which we borrow the name 2.5D data from the Graphics community. In this paper we propose a human pose estimation algorithm based on topological propagation. Geometric Deformable Models are used to carry out such propagation, implemented according to the Narrow Band Level Set approach. A variant of the latter method is proposed, including a density restriction which helps preserving the topological properties of the object under analysis. Principal end-effectors are extracted from a directed graph weighted with geodesic distances, also providing a skeletal-like structure describing human pose. An evaluation against reference methods is performed with promising results. The proposed solution allows a frame-wise end-effector detection, with no temporal tracking involved, which may be generalized to the tracking of other objects beyond human body. 相似文献