A comprehensive analysis of the mean-square learning characteristics of stochastic-descent algorithms is presented. The approach is based on the commonly exploited simplifying assumption of stationary independent trai...
A comprehensive analysis of the mean-square learning characteristics of stochastic-descent algorithms is presented. The approach is based on the commonly exploited simplifying assumption of stationary independent training vectors. Characteristics analyzed include stability, steady-state misadjustment, initial rate of convergence, optimum step size, and steady-state autocovariance and spectral characteristics of the weight-vector. Effects on these characteristics due to degree of randomness of stochastic gradient, particular data distribution, and data corruption are isolated and analyzed. An objective of the work is to keep the number of simplifying assumptions and approximations to a minimum. Comparison of results with previous more approximate analyses are made. Lernkurven von stochastischen Gradienten Algorithmen werden untersucht. Die vereinfachende Annahme von stationären, unabhängigen Trainingsvektoren wird benutzt. Charakteristiken die untersucht werden beinhalten Stabilität, ‘steady state’ Fehlanpassung, Start Konvergenz, optimaler Schritt sowie ‘steady state’ Autokovarianz und spektrale Charakteristik des Gewichtsvektors. Die Effekten auf diese Charakteristiken von dem Zufälligkeitsgrad des stichastischen Gradienten, besonderer Daten Verteilung und Daten Verderbung werden isoliert und analysiert. Ein Zielpunkt dieser Arbeit ist es die Anzahl vereinfachenden Annahmen und Approximationen auf ein minimum zu beschränken. Vergleiche mit Resultaten die von approximativeren Analysen stammen werden gezogen. Une analyse d'ensemble des caractéristiques de convergence de l'erreur quadratique moyenne dans les algorithmes utilisant la décroissance du gradient stochastique est presentée. Cette approche est basée sur l'hypothése simplificatrice classique de stationnarité et indépendance des vecteurs de test. Les caractéristiques analysées comprennent la stabilité, l'écart d'état stable, la vitesse initiale de convergence, le pas optimum d'incrémentation, et l'autocovarian
The implementation of digital filtering algorithms using pipelined vector processors is investigated. Modeling of vector processors and vectorization methods are explained, and then the performances of several impleme...
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The implementation of digital filtering algorithms using pipelined vector processors is investigated. Modeling of vector processors and vectorization methods are explained, and then the performances of several implementation methods are evaluated based on the model. Vector processor implementation of FIR filtering algorithms using the outer product method and the indirect convolution method is evaluated. Recursive and adaptive filtering algorithms, which lead to dependency problems in direct vector processor implementations, are implemented very efficiently using a newly developed vectorization method. The proposed method computes multiple output samples at a time, making the vector length independent of the filter order. Illustrative examples comparing theoretical results with Cray X-MP simulation results are included.
We consider a class of supervisory control problems that require infinite state supervisors Petri nets with inhibitor arcs (PN's) to model the supervisors. We compare this PN-based approach to supervisory control ...
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We consider a class of supervisory control problems that require infinite state supervisors Petri nets with inhibitor arcs (PN's) to model the supervisors. We compare this PN-based approach to supervisory control to automata-based approaches. The primary advantage of a PN-based supervisory controller is that a PN-based controller provides a finite representation of an infinite state supervisor. For verification, implementation, and testing reasons, a finite PN-based representation of an infinite state supervisor is preferred over an automata-based supervisor. We show that this modeling advantage is accompanied by a decision disadvantage, in that in general the controllability of a language that can be generated by the closed-loop system is undecidable.
In this paper the authors derive simple approximate formulas for the performance of entropy-encoded DPCM for a Gaussian random process and a frequency-weighted mean-square distortion measure. Using these results they ...
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In this paper the authors derive simple approximate formulas for the performance of entropy-encoded DPCM for a Gaussian random process and a frequency-weighted mean-square distortion measure. Using these results they compare the performance of DPCM to the information theoretic rate-distortion bound. They study the effect on the performance of DPCM of the spectrum of the input process, the frequency weight in the distortion measure, and the number of prediction coefficients. They also examine briefly the case of achromatic still images using line-by-line and two-dimensional DPCM encoding with intrafield and intraframe information.
A novel framework for parallel subgraph isomorphism on GPUs is proposed, named GPUSI, which consists of GPU region exploration and GPU subgraph matching. The GPUSI iteratively enumerates subgraph instances and solves ...
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A novel framework for parallel subgraph isomorphism on GPUs is proposed, named GPUSI, which consists of GPU region exploration and GPU subgraph matching. The GPUSI iteratively enumerates subgraph instances and solves the subgraph isomorphism in a divide-and-conquer fashion. The framework completely relies on the graph traversal, and avoids the explicit join operation. Moreover, in order to improve its performance, a task-queue based method and the virtual-CSR graph structure are used to balance the workload among warps, and warp-centric programming model is used to balance the workload among threads in a warp. The prototype of GPUSI is implemented, and comprehensive experiments of various graph isomorphism operations are carried on diverse large graphs. The experiments clearly demonstrate that GPUSI has good scalability and can achieve speed-up of 1.4–2.6 compared to the state-of-the-art solutions.
This paper presents a texture segmentation algorithm based on a hierarchical wavelet decomposition. Using Daubechies' four-tap filter, an original image is decomposed into three detail images and one approximate i...
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This paper presents a texture segmentation algorithm based on a hierarchical wavelet decomposition. Using Daubechies' four-tap filter, an original image is decomposed into three detail images and one approximate image. The decomposition can be recursively applied to the approximate image to generate a lower resolution of the pyramid. The segmentation starts at the lowest resolution using the K-means clustering scheme and textural features obtained from various sub-bands. The result of segmentation is propagated through the pyramid to a higher resolution with continuously improving the segmentation. The lower resolution levels help to build the contour of the segmented texture, while higher levels refine the process, and correct possible errors.
We analyze the deflection of a probe beam because of pump-probe interaction in a high-absorbing thermal medium. We extend the existing theory by accounting for translation of a finite-width probe because of deflection...
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We analyze the deflection of a probe beam because of pump-probe interaction in a high-absorbing thermal medium. We extend the existing theory by accounting for translation of a finite-width probe because of deflection within the nonlinear sample. We also provide expressions for the number of resolvable angles of the probe for possible applications of the setup as a beam deflector and study conditions for the maximization of the deflection angle and the resolution. We present experimental results obtained with a solution of chlorophyll in ethanol as the thermal medium.
Plasma immersion ion implantation (PIII) is a technique which promises high dose rate implantation and compatibility with large-area processing. When a large negative bias is applied to the substrate which is immersed...
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Plasma immersion ion implantation (PIII) is a technique which promises high dose rate implantation and compatibility with large-area processing. When a large negative bias is applied to the substrate which is immersed inside a high ion-density plasma, all ion species present will be implanted without ion mass selection, Innovations of this techniques include: implantation time independent of implantation area, capability to perform concomitant deposition and implantation, and simplicity of machine design and maintenance. This paper reports the modeling of PIII plasma dynamics and several demonstrated semiconductor processing applications such as plasma doping, subsurface material synthesis, ion beam mixing, microcavity engineering, and surface modifications. Several processing issues such as substrate charging and dosimetry will also be discussed.
The phase sensitivity with respect to coefficient errors is studied for a class of lattice digital allpass filters. It is shown that corresponding to each lattice parameter there is a set of frequencies for which the ...
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The phase sensitivity with respect to coefficient errors is studied for a class of lattice digital allpass filters. It is shown that corresponding to each lattice parameter there is a set of frequencies for which the phase response remains invariant to an arbitrary perturbation of the parameter. In addition, a simple result of sensitivity “amplification” in lossless two-pair networks is derived, which is used to obtain means and bounds on the sensitivity functions for these lattice structures in term of the lattice parameters. From these results some useful coefficient sensitivity properties are inferred. A practical example is included to better understand the interaction of sensitivity mechanisms in lattice allpass filter realizations, in the context of transfer functions realized as the parallel connection of two allpass filters. Finally, it is shown that the order reduction process intrinsic to the lattice synthesis procedure minimizes the L ∞ norm of the phase sensitivity at each step. Für eine Klasse digitaler Allpaßfilter in Gitterstruktur wird die Empfindlichkeit der Phase gergenüber Koeffizientenfehlern betrachtet. Es wird gezeigt, daß es bezüglich eines jeden Filterparameters gewisse Frequenzpunkte gibt, in denen der Phasengang auch bei beliebiger Parameterverfälschung unverändert bleibt. Darüber hinaus wird in einfacher Form eine “Empfindlichkeits-Verstärkung” in verlustfreien Signalfluß-Zweitor-Netzwerken hergeleitet. Sie wird dazu benützt, Mittel- und Grenzwerte für die Empfindlichkeitsfunktionen dieser Gitterstrukturen, ausgedrückt in den Filterparametern, zu gewinnen. Aus diesen Ergebnissen wird auf einige nützliche Eigenschaften der Koeffizientenempfindlichleit geschlossen. Ein praktisches Beispiel schließt sich an; es dient zum besseren Verständnis des Zusammenwirkens von Empfindlichkeitsmechanismen in Gitterstruktur-Allpässen, wie sie zur Realisierung von Übertrangungsfunktionen durch eine parallel-Anordnung von zwei Allpaßfiltern verwendet werden.
The effects of wafer bias and plasma parameters on thin oxide charging during plasma immersion ion implantation (PIII) are simulated. The simulator has been shown to determine accurately the charging currents generate...
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The effects of wafer bias and plasma parameters on thin oxide charging during plasma immersion ion implantation (PIII) are simulated. The simulator has been shown to determine accurately the charging currents generated during PIII. The dependence of the plasma electron temperature, ion density and plasma uniformity on charging damage in metal oxide semiconductor capacitor structures is investigated. A lower plasma electron temperature is shown to reduce charging damage. Simulation and experimental results show that for a given voltage pulse waveform there is a range of bias repetition rates allowed by limiting the charging damage below a threshold value. Within this range there exists a switch-over repetition rate that minimizes the charging damage.
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