1,289 research outputs found

    Investigating the impact of image content on the energy efficiency of hardware-accelerated digital spatial filters

    Get PDF
    Battery-operated low-power portable computing devices are becoming an inseparable part of human daily life. One of the major goals is to achieve the longest battery life in such a device. Additionally, the need for performance in processing multimedia content is ever increasing. Processing image and video content consume more power than other applications. A widely used approach to improving energy efficiency is to implement the computationally intensive functions as digital hardware accelerators. Spatial filtering is one of the most commonly used methods of digital image processing. As per the Fourier theory, an image can be considered as a two-dimensional signal that is composed of spatially extended two-dimensional sinusoidal patterns called gratings. Spatial frequency theory states that sinusoidal gratings can be characterised by its spatial frequency, phase, amplitude, and orientation. This article presents results from our investigation into assessing the impact of these characteristics of a digital image on the energy efficiency of hardware-accelerated spatial filters employed to process the same image. Two greyscale images each of size 128 × 128 pixels comprising two-dimensional sinusoidal gratings at maximum spatial frequency of 64 cycles per image orientated at 0° and 90°, respectively, were processed in a hardware implemented Gaussian smoothing filter. The energy efficiency of the filter was compared with the baseline energy efficiency of processing a featureless plain black image. The results show that energy efficiency of the filter drops to 12.5% when the gratings are orientated at 0° whilst rises to 72.38% at 90°

    Existence and uniqueness of solutions for a degenerate quasilinear parabolic problem

    Get PDF
    We consider the following quasilinear parabolic equation of degenerate type with convection term ut=φ(u)xx+b(u)xu_t=\varphi (u)_{xx}+b(u)_x in (L,0)×(0,T)(-L,0)\times (0,T). We solve the associate initial-boundary data problem, with nonlinear flux conditions. This problem, describes the evaporation of an incompressible fluid from a homogeneous porous media. The nonlinear condition in x=0x=0, means that the flow of fluid leaving the porous media depends on variable meteorological conditions and in a nonlinear manner on uu. In x=Lx=-L, we have an impervious boundary. For a sufficiently smooth initial data, one proves the existence and uniqueness of the global strong solution in the class of bounded variation functions

    L’Iran en mutation industrielle

    Get PDF

    Existence and uniqueness of periodic solutions for a nonlinear reaction-diffusion problem

    Get PDF
    We consider a class of degenerate reaction-diffusion equations on a bounded domain with nonlinear flux on the boundary. These problems arise in the mathematical modelling of flow through porous media. We prove, under appropriate hypothesis, the existence and uniqueness of the nonnegative weak periodic solution. To establish our result, we use the Schauder fixed point theorem and some regularizing arguments

    Challenging the Assumptions of Unconstrained Electronic Trade across the Internet Space

    Get PDF
    We examine the prevailing factors influencing the uptake, scope and modality of internet-worked trade amongst Small and Medium Enterprises (SMEs) and the extent to which this effectively re-defines our notions of what constitutes viable and attractive local, regional or global trading zones as viewed by SMEs for the purpose of Electronic Commerce (EC). It is noted that such de-facto re-definitions, for some potential internet transactors, may arise through their preference to operate within the virtual sub-space confined to those zones or modes of electronic trade which are perceived by them as relatively more familiar and secure. The factors responsible for the paradox between this and the modern market metaphors of global village and virtual borderless world are examined in the context of evolving notions of virtual network enterprises or Net-conurbations with the development of intranets and extranets

    Stable Irregular Dynamics in Complex Neural Networks

    Full text link
    For infinitely large sparse networks of spiking neurons mean field theory shows that a balanced state of highly irregular activity arises under various conditions. Here we analytically investigate the microscopic irregular dynamics in finite networks of arbitrary connectivity, keeping track of all individual spike times. For delayed, purely inhibitory interactions we demonstrate that the irregular dynamics is not chaotic but rather stable and convergent towards periodic orbits. Moreover, every generic periodic orbit of these dynamical systems is stable. These results highlight that chaotic and stable dynamics are equally capable of generating irregular activity.Comment: 10 pages, 2 figure

    Fundamentos del método científico = (Fundamentals of the scientific methodology)

    Get PDF
    El objetivo de esta obra no radica en realizar una búsqueda exhaustiva de la literatura en el tema, sino, sentar las bases del método científico, notando los aspectos filosóficos e éticos de la ciencia. Se presentan los conceptos y definiciones fundamentales relacionados con la metodología de la investigación científica. Se maneja el concepto de la toma de los datos válidos como un requisito básico en cualquier trabajo científico. Se pone a disposición del lector un modelo denominado el ECOEE que es una herramienta poderosa para establecer puntos de comparación e discusión entre los resultados de diferentes trabajos científicos. Finalmente, ofrece unas sugerencias de que hacer o no hacer en cuanto a realizar un trabajo de investigación. The aim of this paper is not to conduct a thorough literature search on the subject material, but to stress the fundamentals of the scientific methodology along with the philosophical and ethical issues thereof. The basic concepts and definitions in relation to research methodology are presented. The concept of data collection as a basic requisite in any scientific work is discussed. The ECOEE model as a strong tool in establishing different points of view and comparison among the results of different scientific works are laid out. Finally, some tips and suggestions are given as what to do or to avoid in conducting scientific research

    Desarrollo sustentable: fundamentos, perspectivas y limitaciones (Sustainable development: fundamentals, prespectives & limitations)

    Get PDF
    Se explican la filosofía, las nociones y los conceptos fundamentales del desarrollo sustentable, y enfatizan los desastres socioeconómicos, políticos e ecológicos que amenazan seriamente a la humanidad entera. Contrastan las diferencias abismales entre los países desarrollados y los país pobres y en vía de desarrollo. Se mencionan los intentos fallidos del ser humano conciente desde 1972 (la Declaración de Estocolmo) al tratar de buscar salidas a los problemas ambientales y enfatizan los intereses de los conglomerados superpoderosos como obstáculos al progreso del desarrollo sustentable. Se mencionan los indicadores de sustentabilidad y también los índices con énfasis sobre la estimación de los factores de educación, salud, pobreza, medioambiente e ecología. Se define el concepto de la biodiversidad y los modelos matemáticos de uso actual para su estimación. The basic philosophy, notions and concepts of sustainable development are laid out and the socioeconomic, political and ecological disasters that threaten the entire humanity are stressed. The huge differences among the developed, poor and developping countries are cotrasted. The failed intents of the conciencious man, since the Declaration of Stockholm (1972), in search of solutions to the environmental problems are pointed out, and the interests of the superpower conglomerates as a hinderance to the advancement of the sustainable development are mentioned. The indices of the sustainable development are mentioned with a particular emphasis on the estimation of some factors such as the education, health, poverty, the enviroment and the ecology. The concept of biodiversity is defined and the current mathematical models for its estimation are noted
    corecore