In this paper we address the limits of the semiclassical models used till now in solid state physics to describe the electronic conductance of a wire. We provide an overview of the Quantized Conductance behavior repor...
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Color space conversion is an important kernel in multimedia codecs such as JPEG and MPEG. When implemented using SIMD instructions, however, the performance improvement is often limited due to two reasons. First, corr...
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ISBN:
(纸本)0769527469;9780769527468
Color space conversion is an important kernel in multimedia codecs such as JPEG and MPEG. When implemented using SIMD instructions, however, the performance improvement is often limited due to two reasons. First, corresponding color space components are stored at non-unit strides and, second, intermediate results can be larger than 8 bits. In this paper we show that extended subwords and the matrix register file (MRF) can be employed to mitigate these limitations. These techniques avoid rearrangement instructions and increase the number of subwords that are processed in parallel. Experimental results have been obtained by extending the SimpleScalar toolset. The results show that extended subwords and the MRF yield a speedup of up to 2.45x and 1.78x over MMX for the RGB-to-YCbCr and YCbCr-to-RGB kernels, respectively. Compared to C implementations, speedups of up to 10.09x and 6.74x, respectively, are obtained. Additionally, the results show that the speedup over MMX is higher for low issue rates. This means that extended subwords and the MRF are suitable techniques for embedded multimedia systems where high issue rates and out-of-order execution are too expensive. The results also show that using more registers improves performance substantially
computer software and the software development process belong to the class of complex systems. Continues monitoring and analysis of development process is crucial to minimize risk. For that reason many metrics and mon...
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computer software and the software development process belong to the class of complex systems. Continues monitoring and analysis of development process is crucial to minimize risk. For that reason many metrics and monitoring tools were developed. Most of metrics are programming language dependent. In the present paper we introduce a tool for analyzing program complexity using chaos theory, especially the idea of the logistic map. It enables assessment of current state of the software development process based on previous software revisions. Analysis is programming language independent and also enables analysis of object and compiled code.
The purpose of this paper is to introduce an novel edge detector using directional wavelet transform and signal registration. Directional wavelet transform decomposes an image into four-dimensional space which augment...
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The purpose of this paper is to introduce an novel edge detector using directional wavelet transform and signal registration. Directional wavelet transform decomposes an image into four-dimensional space which augments the image by the scale and directional information. We show the directional information significantly improves edge detection in noisy images in comparison with the classical multiscale edge detector, and enables more reliable edge tracing along an object boundary. Edge detection is based on the modulus maximum principle with an adaptive threshold whose value is calculated via maximum entropy measure. Edge tracing is done with signal alignment between neighbour edges
This paper presents a new hierarchical method of the edge relaxation by using an edge confidence measure. Proposed method is an adaptive and based on directional hierarchical image decomposition and an edge connecting...
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This paper presents a new hierarchical method of the edge relaxation by using an edge confidence measure. Proposed method is an adaptive and based on directional hierarchical image decomposition and an edge connecting algorithm. It is shown that such combination has low sensitivity to noise, while it is highly robust to outliers, and provide a quality edge connection mechanism
The purpose of this paper is to introduce a novel image enhancement technique by using directional wavelet transform. Directional wavelet transform decomposes an image into four-dimensional space which augments the im...
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The purpose of this paper is to introduce a novel image enhancement technique by using directional wavelet transform. Directional wavelet transform decomposes an image into four-dimensional space which augments the image by the scale and directional information. We show the directional information significantly improves image enhancement in noisy images in comparison with the classical techniques. Image enhancement is based on the multiscale singularity detection with an adaptive threshold whose value is calculated via maximum entropy measure. The proposed technique was tested on synthetic images at different signal-to-noise ratios and clinical images
A new robust adaptive control design synthesis, which employs both high-order neural networks and math-analytical results, for a class of complex nonlinear mechatronic systems possessing similarity property has been d...
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A closed‐form analytic time‐domain expression is obtained for the scalar wave function associated with the reflection of a point‐source excited impulsive spherical wave by a planar boundary with absorptive and disp...
A closed‐form analytic time‐domain expression is obtained for the scalar wave function associated with the reflection of a point‐source excited impulsive spherical wave by a planar boundary with absorptive and dispersive properties. The physical properties of the boundary are modeled as a local Dirichlet‐to‐Neumann boundary condition in the form of a time‐convolution integral, the kernel function in which (denoted as the boundary’s time‐domain admittance) meets the conditions for linear, time‐invariant, causal, passive behavior. Parametrizations of the boundary admittance function are put forward that have the property of showing up explicitly, and in a relatively simple manner, in the expression for the reflected wave field. The partial fraction representation of the time Laplace‐transform domain boundary admittance and the plane‐wave admittance representation are shown to serve the purpose. The expression for the reflected wave field is constructed through an appropriate combination of the modified Cagniard method for analyzing wave propagation in layered media, Lerch’s uniqueness theorem of the unilateral Laplace transformation, and the Schouten‐Van der Pol theorem pertaining to a change of transform parameter in this transformation. The result can serve as a benchmark solution to the modeling of transient wave reflection against absorptive and dispersive boundaries in more complicated geometries where numerical methods are the tool of analysis. The obtained analytical expressions show that, in the configuration under consideration, no true surface waves occur along the boundary.
The frequency-domain exponential transfer function of a delay function cannot be realized with a finite number of lumped elements. Therefore an approximation of a rational quotient of polynomials has to be used. While...
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The frequency-domain exponential transfer function of a delay function cannot be realized with a finite number of lumped elements. Therefore an approximation of a rational quotient of polynomials has to be used. While the use of Bessel polynomials results in the well-known all-pole Bessel-Thomson approximation, a Taylor expansion of the exponential transfer function of a delay around one point results in another type of rational transfer, known as Pade approximation. Although a Bessel-Thomson approximation results in an overshoot-free step response it has slower response and smaller bandwidth in comparison to a Pade-approximated delay. Unfortunately, the latter suffers from overshoot. To reduce the overshoot but preserve the fast-response and large-bandwidth properties, a new delay approximation method is introduced. The method is based on approximation of the delta time-domain response of an ideal delay by a narrow Gaussian time-domain impulse response. The subsequent Pade approximation of the corresponding Gaussian transfer function yields a rational transfer function that is ready for implementation in an analog fashion and realizes a delay with both a large bandwidth and little overshoot
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