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11.
In this paper, a contour-based focus of attention approach is presented. Fast to compute, contour based features are extracted from 3D scenes and matched to model parts of objects. Local reference frames associated with the features induce a translation and rotation, resulting in a vote being cast for the presence of the object in a certain position within the scene. In these positions, HoG features are extracted and SVM classification is applied. Detection results and computation times are compared to those corresponding to a sliding window approach. 相似文献
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Abstract A detailed study of image and Fourier transform formation by GRIN lenses is presented. It is shown how, within paraxial approximation, GRIN lenses exhibit similar behaviour to those of conventional lenses. 相似文献
14.
Ramón R. Palacio Christian O. Acosta Joaquín Cortez Alberto L. Morán 《Universal Access in the Information Society》2017,16(1):103-113
The purpose of this study was to evaluate the usability perception of seniors on video game use with different control devices. Twenty-four seniors participated in the study (12 women, 12 men, 69 years old in average) and eight children (8 years old in average). The setting included the use of two Kinect motion sensors, three computers, three projectors, three video cameras, two audio devices, the Angry Birds and Happy Sky videogames, one Xbox 360 console, a Nintendo Wii device and a Touchscreen configured so that participants could play the games in senior–child pairs. Data were collected according to user friendliness, experience and social interaction. This study suggests that video game control devices for seniors should be adapted to compensate for their function, sensor and cognitive limitations. 相似文献
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16.
Horizontal Dip‐Spin Casting of aqueous alumina‐polyvinylpyrrolidone suspensions with chopped fiber 下载免费PDF全文
Valerie Wiesner Manuel Acosta Lisa Rueschhoff Jeffrey Youngblood Rodney Trice 《International Journal of Applied Ceramic Technology》2017,14(6):1077-1087
A novel ceramic processing method, called Horizontal Dip Spin Casting (HDSC), enabled fabrication of tubular ceramic parts with an aligned chopped fiber phase. HDSC was demonstrated using highly loaded aqueous alumina suspensions with >50 vol.% solids loading and ≤5 vol.% water‐soluble polymer employed as a rheological modifier. Chopped carbon fibers were added to the suspensions to attain maximum loadings of 30 vol.%. During forming, cylindrical foam molds were dipped into the suspension while being rotated radially about the long axis. Simultaneously, a doctor blade was placed at a specified distance from the foam surface to facilitate the flow of the suspension to align the fiber and control the thickness of the material that accrued on the mold. Rheological study of alumina‐PVP suspensions with and without chopped carbon fiber showed that the suspensions exhibited a yield‐pseudoplastic flow behavior. The degree of alignment of the carbon fiber phase in the green bodies was characterized for various suspension formulations, carbon fiber contents and forming speeds. Stereological characterization of green body specimens confirmed the effectiveness of HDSC to attain the desired tubular geometry with considerable fiber alignment for a suspension composition containing ≤20 vol.% chopped fibers. 相似文献
17.
Laura Frutos-Rincn Jos Antonio Gmez-Snchez Almudena Íigo-Portugus M. Carmen Acosta Juana Gallar 《International journal of molecular sciences》2022,23(6)
The cornea is an avascular connective tissue that is crucial, not only as the primary barrier of the eye but also as a proper transparent refractive structure. Corneal transparency is necessary for vision and is the result of several factors, including its highly organized structure, the physiology of its few cellular components, the lack of myelinated nerves (although it is extremely innervated), the tightly controlled hydration state, and the absence of blood and lymphatic vessels in healthy conditions, among others. The avascular, immune-privileged tissue of the cornea is an ideal model to study the interactions between its well-characterized and dense sensory nerves (easily accessible for both focal electrophysiological recording and morphological studies) and the low number of resident immune cell types, distinguished from those cells migrating from blood vessels. This paper presents an overview of the corneal structure and innervation, the resident dendritic cell (DC) subpopulations present in the cornea, their distribution in relation to corneal nerves, and their role in ocular inflammatory diseases. A mouse model in which sensory axons are constitutively labeled with tdTomato and DCs with green fluorescent protein (GFP) allows further analysis of the neuro-immune crosstalk under inflammatory and steady-state conditions of the eye. 相似文献
18.
C. Magaña-Zavala M. E. Angeles-San Martin F. J. Rodríguez-Gómez D. R. Acosta R. Avila-Godoy A. López-Suárez 《Surface Engineering and Applied Electrochemistry》2010,46(2):115-119
Nickel thin films with regular configuration and similar thickness were deposited on steel AISI 1018 (UNSG 10180) by two different
techniques: magnetron sputtering and electrolytic process. The main aim of this work is to compare the surfaces deposited
films made by the two techniques using the scanning electronic microscopy and to identify their morphological differences
and imperfections. We evaluate the protective coatings properties when the films are in contact with an acid medium. We also
study the thin films coatings by the spectroscopy impedance technique. We obtain that the sputtering deposits present a homogeneous
thin film coating that is better than the one obtained by the electrolytic technique. It is expected that the thin film coatings
made in this work can protect the steel against corrosion when it is in contact with an acid environment. 相似文献
19.
Interconnection and damping assignment passivity-based control of mechanical systems with underactuation degree one 总被引:1,自引:0,他引:1
Acosta J.A. Ortega R. Astolfi A. Mahindrakar A.D. 《Automatic Control, IEEE Transactions on》2005,50(12):1936-1955
Interconnection and damping assignment passivity-based control is a new controller design methodology developed for (asymptotic) stabilization of nonlinear systems that does not rely on, sometimes unnatural and technique-driven, linearization or decoupling procedures but instead endows the closed-loop system with a Hamiltonian structure with a desired energy function-that qualifies as Lyapunov function for the desired equilibrium. The assignable energy functions are characterized by a set of partial differential equations that must be solved to determine the control law. We prove in this paper that for a class of mechanical systems with underactuation degree one the partial differential equations can be explicitly solved. Furthermore, we introduce a suitable parametrization of assignable energy functions that provides the designer with a handle to address transient performance and robustness issues. Finally, we develop a speed estimator that allows the implementation of position-feedback controllers. The new result is applied to obtain an (almost) globally stabilizing scheme for the vertical takeoff and landing aircraft with strong input coupling, and a controller for the pendulum in a cart that can swing-up the pendulum from any position in the upper half plane and stop the cart at any desired location. In both cases we obtain very simple and intuitive position-feedback solutions. 相似文献
20.
A dynamic event tree method for analyzing the risk associated with dynamic nuclear power plant accident sequences is presented. The method provides a framework for treating stochastic variations in operating crew states (defined by substrates characterizing the accident diagnosis, the planned actions, and the crew quality) as well as stochastic variations in hardware states. Plant process variables are treated deterministically; they are used when determining the likelihood of stochastic branchings. The method is used in an analysis of a steam generator tube rupture (SGTR) accident; it is shown that a number of important operator behavior patterns can be reasonably represented, and that, comparing with conventional event trees, sources of dependencies between failure events can be better defined. 相似文献