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Target oriented branch & bound method for global optimizationStix, Volker January 2002 (has links) (PDF)
We introduce a very simple but efficient idea for branch & bound (B&B) algorithms in global optimization (GO). As input for our generic algorithm, we need an upper bound algorithm for the GO maximization problem and a branching rule. The latter reduces the problem into several smaller subproblems of the same type. The new B&B approach delivers one global optimizer or, if stopped before finished, improved upper and lower bounds for the problem. Its main difference to commonly used B&B techniques is its ability to approximate the problem from above and from below while traversing the problem tree. It needs no supplementary information about the system optimized and does not consume more time than classical B&B techniques. Experimental results with the maximum clique problem illustrate the benefit of this new method. (author's abstract) / Series: Working Papers on Information Systems, Information Business and Operations
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Data Structuring Problems in the Bit Probe ModelRahman, Mohammad Ziaur January 2007 (has links)
We study two data structuring problems under the bit probe model: the dynamic predecessor problem and integer representation in a manner supporting basic updates in as few bit operations as possible. The model of computation considered in this paper is the bit probe model. In this model, the complexity measure counts only the bitwise accesses to the data structure. The model ignores the cost of computation. As a result, the bit probe complexity of a data structuring problem can be considered as a fundamental measure of the problem. Lower bounds derived by this model are valid as lower bounds for any realistic, sequential model of computation. Furthermore, some of the problems are more suitable for study in this model as they can be solved using less than $w$ bit probes where $w$ is the size of a computer word.
The predecessor problem is one of the fundamental problems in computer science with numerous applications and has been studied for several decades. We study the colored predecessor problem, a variation of the predecessor problem, in which each element is associated with a symbol from a finite alphabet or color. The problem is to store a subset $S$ of size $n,$ from a finite universe $U$ so that to support efficient insertion, deletion and queries to determine the color of the largest value in $S$ which is not larger than $x,$ for a given $x \in U.$ We present a data structure for the problem that requires $O(k \sqrt[k]{{\log U} \over {\log \log U}})$ bit probes for the query and $O(k^2 {{\log U} \over {\log \log U}})$ bit probes for the update operations, where $U$ is the universe size and $k$ is positive constant. We also show that the results on the colored predecessor problem can be used to solve some other related problems such as existential range query, dynamic prefix sum, segment representative, connectivity problems, etc.
The second structure considered is for integer representation. We examine the problem of integer representation in a nearly minimal number of bits so that increment and decrement (and indeed addition and subtraction) can be performed using few bit inspections and fewer bit changes. In particular, we prove a new lower bound of $\Omega(\sqrt{n})$ for the increment and decrement operation, where $n$ is the minimum number of bits required to represent the number. We present several efficient data structures to represent integers that use a logarithmic number of bit inspections and a constant number of bit changes per operation.
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Morphed Potential Energy Surfaces from the Spectroscopy of Weakly Bound ComplexesRivera-Rivera, Luis A. 2011 May 1900 (has links)
In this research the so-called potential morphing method was used to generate reliable interaction potential energy surfaces for weakly bound complexes. The potential morphing method is based on the optimization of modified computed ab initio potential energy surfaces to give predicted spectroscopic data, in agreement with the experimental values. In the standard potential morphing procedure the computed ab initio potential is adjusted by scaling, shifting, and dilating transformations to reproduce the experimental data.
In this research, selected systems have been chosen to be studied based on the availability of varied and accurate sets of experimental data. In the present work, accurate interaction potential energy surfaces are obtained for the weakly bound complexes: Ne:HCl, OC:HX (X = F, Cl, Br, I) and HI:CO2. A comprehensive study on the interaction potential of these systems provides fundamental perspectives on the influence of different intermolecular forces. In addition the ground state isotopic isomerization observed in the OC:HI system may suggest a possible structural change of proteins, and other biological macromolecules, in deuterated solvents.
In this dissertation, an alternative approach to morphing the potential energy surfaces of non-covalent interactions is also presented. In this approach the morphed potential is generated as a linear combination of ab initio potentials, that are computed at different levels of theory. This new morphing approach is applied to OC:HCl and is found to be of similar accuracy to that of the previous morphing method. In addition, this new method is also extended from four-dimensions to six-dimensions and is applied to the OC:HF system to obtain a vibrationally-complete six-dimensional morphed potential.
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Minimum Diameter Double-Loop NetworksGao, Ying-Yao 21 July 2002 (has links)
Abstract
¡@¡@Double-loop networks have become one of the most popular architectures in the design of Local Area Networks and distributed memory multiprocessor systems. This is due to its characters of minimal diameter, easy routing, expandability and regularity. The switching mechanism at each node can easily be implemented using building blocks of the same specification. Therefore, double-loop networks have a high degree of reliability and hence very low vulnerability. Let N denote the number of nodes in a double-loop network and d(N) be the best possible diameter with N vertices. Given an N, Bermond et al. [5], Boesch and Wang [7], and Yebra et al. [23] have shown that . This is a well-known lower bound for d(N) and is usually denoted as lb(N). In this paper, what we discuss is finding an optimal topology such that d(N)= lb(N) for any given value of N. We provide a simple formula to find optimal topologies of double-loop networks with N nodes.
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Optimized upper bound analysis of polymer coated metal rod extrusion through conical dieShah, Ritesh Lalit 17 September 2007 (has links)
Extrusion is a metal forming process used extensively in industry to produce different
structural, mechanical, electrical, architectural, automotive and aerospace application
parts. Currently after extrusion, the rod is subjected to environmental wear due to long
storage time and hence requires an additional cleaning process before further use. This
cleaning process can be eliminated by extruding a polymer coated metal rod workpiece
such that the polymer coating is sustained on the final product after the extrusion
process.
In the present research study a new upper bound analytical model is developed to predict
the forces required to conduct extrusion of a polymer coated metal rod successfully. The
search for the lower upper bound power functional is modeled as a non linear
optimization problem. Optimizing the functional also determines the set of constraints
defining the shape of rigid plastic deformation boundaries and the final coating
thickness. Also an upper bound analytical model was developed to predict forces for
failure of the polymer coating during the extrusion. Both the analytical models for successful and failed extrusion are compared to obtain critical die angle which can
provide tooling and process design guidelines. Finite element analysis simulations were
modeled using commercially available software package, ABAQUS. Predictions of FEA
simulations were in good agreement with published results and with the predictions of
analytical model developed in this study.
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THE EFFECTS OF COOKED COMMON BEANS ON DSS-INDUCED COLITIS IN MICEZHANG, PENGLIHUI CLAIRE 13 September 2012 (has links)
This thesis is an investigation of the effects of whole beans, with different levels of phenolics level, on colonic inflammation in mice. C57BL/6 male mice were fed a basal diet (BD) supplemented with or without 20% bean flour for 3 weeks. Colitis was induced by 2% dextran sulphate sodium (DSS) in mice drinking water. Phenolic determinations of the bean flours revealed that within each pair of beans, the darker bean had higher phenolic content and antioxidant activity compared to the lighter one. In addition, only coloured beans had anthocyanin. When bean were consumed both prior to and during DSS cycle, the mice experienced both disease attention and aggravation. However, when bean consumption was limited to prior to DSS induction only, mice had reduced colitis upon later DSS induction. Overall, findings suggest that the effects of bean may differ depending on the timing of consumption. / Agriculture and Agri-Food of Canada, Ontario Ministry of Agriculture and Rural Affairs
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Heuristic scheduling procedures to achieve workload balance on parallel processorsWhite, Emett Robert 12 1900 (has links)
No description available.
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Arc-path approaches to fixed charge network problemsChoe, Ui Chong 12 1900 (has links)
No description available.
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Likelihood-Based Modulation Classification for Multiple-Antenna ReceiversRamezani-Kebrya, Ali 21 September 2012 (has links)
Prior to signal demodulation, blind recognition of the modulation
scheme of the received signal is an important task for intelligent
radios in various commercial and military applications such as
spectrum management, surveillance of broadcasting activities and adaptive
transmission. Antenna arrays provide spatial diversity and increase channel
capacity. This thesis focuses on the algorithms and performance analysis of
the blind modulation classification (MC) for a multiple antenna receiver configuration.
For a single-input-multiple-output (SIMO) configuration with unknown channel amplitude, phase, and noise variance, we
investigate likelihood-based algorithms for linear digital MC. The existing
algorithms are presented and extended to SIMO. Using recently proposed blind estimates of the unknown parameters, a
new algorithm is developed. In addition, two upper bounds on the classification performance of MC
algorithms are provided. We derive the exact Cramer-Rao Lower Bounds (CRLBs) of joint estimates of the unknown parameters for one- and two-dimensional amplitude modulations. The asymptotic behaviors of the CRLBs are obtained for the high signal-to-noise-ratio (SNR) region. Numerical results demonstrate the accuracy of the CRLB expressions and confirm that the expressions in the literature are special cases of our results. The classification performance of the proposed algorithm is compared with the existing algorithm and upper bounds. It is shown that the proposed algorithm outperforms the existing one significantly with reasonable computational complexity.
The proposed algorithm in this thesis can be used in modern intelligent radios equipped with multiple antenna receivers
and the provided performance analysis, i.e., the CRLB expressions, can be employed to design practical systems involving estimation of the unknown parameters
and is not limited to MC. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2012-09-21 00:51:43.938
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Quadratische Diophantische Gleichungen über algebraischen Zahlkörpern / Quadratic diophantine equations over algebraic number fieldsHelfrich, Lutz 20 March 2015 (has links)
No description available.
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