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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Kernel based learning methods for pattern and feature analysis

Wu, Zhili 01 January 2004 (has links)
No description available.
62

A 3-d capacitance extraction algorithm based on kernel independent hierarchical method and geometric moments

Zhuang, Wei 17 September 2007 (has links)
A three dimensional (3-D) capacitance extraction algorithm based on a kernel independent hierarchical method and geometric moments is described. Several techniques are incorporated, which leads to a better overall performance for arbitrary interconnect systems. First, the new algorithm hierarchically partitions the bounding box of all interconnect panels to build the partition tree. Then it uses simple shapes to match the low order moments of the geometry of each box in the partition tree. Finally, with the help of a fast matrix-vector product, GMRES is used to solve the linear system. Experimental results show that our algorithm reduces the linear system's size greatly and at the same time maintains a satisfying accuracy. Compared with FastCap, the running time of the new algorithm can be reduced more than a magnitude and the memory usage can be reduced more than thirty times.
63

Rootkits

Li, Jie, Lu, Yuting January 2010 (has links)
Abstract:The kernel system of Windows is more thoroughly exposed to people. So, thekernel-level Rootkits techniques are now laid on greater emphasis. It is very importantto maintain the security of computers and to conduct an in-depth research on theoperational mechanism by using kernel-level Rootkits in hiding its traces. Since theinvolved core techniques are beginning to catch on nowadays, we should analyzesome new key techniques employed for application of Rootkits, discuss the specificmethods and propose a set of defense strategy for computer security.
64

Polyanalytic Bergman Kernels

Haimi, Antti January 2013 (has links)
The thesis consists of three articles concerning reproducing kernels ofweighted spaces of polyanalytic functions on the complex plane. In the first paper, we study spaces of polyanalytic polynomials equipped with a Gaussianweight. In the remaining two papers, more general weight functions are considered. More precisely, we provide two methods to compute asymptotic expansions for the kernels near the diagonal and then apply the techniques to get estimates for reproducing kernels of polyanalytic polynomial spaces equipped with rather general weight functions. / <p>QC 20130513</p>
65

Continuous Occupancy Mapping Using Gaussian Processes / Kontinuerlig kartering med Gaussprocesser

Wågberg, Johan, Walldén Viklund, Emanuel January 2012 (has links)
The topic of this thesis is occupancy mapping for mobile robots, with an emphasis on a novel method for continuous occupancy mapping using Gaussian processes. In the new method, spatial correlation is accounted for in a natural way, and an a priori discretization of the area to be mapped is not necessary as within most other common methods. The main contribution of this thesis is the construction of a Gaussian process library for C++, and the use of this library to implement the continuous occupancy mapping algorithm. The continuous occupancy mapping is evaluated using both simulated and real world experimental data. The main result is that the method, in its current form, is not fit for online operations due to its computational complexity. By using approximations and ad hoc solutions, the method can be run in real time on a mobile robot, though not without losing many of its benefits.
66

Weighted Bergman Kernel Functions and the Lu Qi-keng Problem

Jacobson, Robert Lawrence 2012 May 1900 (has links)
The classical Lu Qi-keng Conjecture asks whether the Bergman kernel function for every domain is zero free. The answer is no, and several counterexamples exist in the literature. However, the more general Lu Qi-keng Problem, that of determining which domains in Cn have vanishing kernels, remains a difficult open problem in several complex variables. A challenge in studying the Lu Qi-keng Problem is that concrete formulas for kernels are generally difficult or impossible to compute. Our primary focus is on developing methods of computing concrete formulas in order to study the Lu Qi-keng Problem. The kernel for the annulus was historically the first counterexample to the Lu Qi-keng Conjecture. We locate the zeros of the kernel for the annulus more precisely than previous authors. We develop a theory giving a formula for the weighted kernel on a general planar domain with weight the modulus squared of a meromorphic function. A consequence of this theory is a technique for computing explicit, closed-form formulas for such kernels where the weight is associated to a meromorphic kernel with a finite number of zeros on the domain. For kernels associated to meromorphic functions with an arbitrary number of zeros on the domain, we obtain a weighted version of the classical Ramadanov's Theorem which says that for a sequence of nested bounded domains exhausting a limiting domain, the sequence of associated kernels converges to the kernel associated to the limiting domain. The relationship between the zeros of the weighted kernels and the zeros of the corresponding unweighted kernels is investigated, and since these weighted kernels are related to unweighted kernels in C^2, this investigation contributes to the study of the Lu Qi-keng Problem. This theory provides a much easier technique for computing certain weighted kernels than classical techniques and provides a unifying explanation of many previously known kernel formulas. We also present and explore a generalization of the Lu Qi-keng Problem.
67

Cylinder kernel expansion of Casimir energy with a Robin boundary

Liu, Zhonghai 30 October 2006 (has links)
We compute the Casimir energy of a massless scalar field obeying the Robin boundary condition on one plate and the Dirichlet boundary condition on another plate for two parallel plates with a separation of alpha. The Casimir energy densities for general dimensions (D = d + 1) are obtained as functions of alpha and beta by studying the cylinder kernel. We construct an infinite-series solution as a sum over classical paths. The multiple-reflection analysis continues to apply. We show that finite Casimir energy can be obtained by subtracting from the total vacuum energy of a single plate the vacuum energy in the region (0,∞)x R^d-1. In comparison with the work of Romeo and Saharian(2002), the relation between Casimir energy and the coeffcient beta agrees well.
68

A 3-d capacitance extraction algorithm based on kernel independent hierarchical method and geometric moments

Zhuang, Wei 17 September 2007 (has links)
A three dimensional (3-D) capacitance extraction algorithm based on a kernel independent hierarchical method and geometric moments is described. Several techniques are incorporated, which leads to a better overall performance for arbitrary interconnect systems. First, the new algorithm hierarchically partitions the bounding box of all interconnect panels to build the partition tree. Then it uses simple shapes to match the low order moments of the geometry of each box in the partition tree. Finally, with the help of a fast matrix-vector product, GMRES is used to solve the linear system. Experimental results show that our algorithm reduces the linear system's size greatly and at the same time maintains a satisfying accuracy. Compared with FastCap, the running time of the new algorithm can be reduced more than a magnitude and the memory usage can be reduced more than thirty times.
69

Using standard operating systems for time critical applications with special emphasis on LINUX /

Heursch, Arnd Christian. January 2006 (has links) (PDF)
Univ. der Bundeswehr, Diss.--München, 2006.
70

Dynamic Nature of Heterosis and Determination of Sink Size in Maize

Smith, Nathan C 04 September 2012 (has links)
Heterosis, the phenotypic superiority of first generation progeny over that of its inbred parents, has been extensively investigated. However, differences in the phenology and dynamic growth patterns between parents and offspring provide challenges in understanding causal factors behind superior trait values. For maize, manipulation of heterosis to increase grain yield has been of primary importance, and the number of spikelets that develop on the female inflorescence is the primary determinant of grain yield. The initial experiment examined heterosis in genetic backgrounds that led to minimal differences in phenology and plant architecture. Growth curves were used to characterize the dynamic expression of heterosis between the hybrid and the inbred parents for a series of vegetative and reproductive traits across stages of development. The second experiment was conducted to determine the effects that stress due to planting density might have on the number of properly developed spikelets, as the first experiment, along with results from the literature, provided evidence to suggest that a proportion of the later forming spikelets found on the distal portion of the female inflorescence were not capable of producing kernels. Results from the initial experiment suggested that expression of heterosis for individual characteristics – such as fresh weight, whose percent mid-parent heterosis was 82% at V4 and declined steadily to 17% at V11 – begins at a high level and decreased during development. On a whole plant level – as determined by a combined analysis of the values and growth rates of the individual characteristics – heterosis increases throughout development until it reaches a steady-state level. Results from the second experiment indicated that increasing plant density did not affect the total number of spikelets per ear but decreased the number of kernels per ear, and it was found that the number of properly developed spikelets per ear was equal to the number of kernels per ear in eight of the nine genotypes tested. Optimal growth stages for more in-depth investigation of transcriptomic changes that may identify causal genetic factors of heterosis for yield were not found, and stress increases the proportion of improperly developed spikelets causing a loss in kernel number. / Natural Sciences and Engineering Research Council of Canada, Ontario Ministry of Agriculture, Food and Rural Affairs, Canadian Foundation for Innovation, and Ontario Innovative Trust

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