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2009

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Articles 4651 - 4680 of 7615

Full-Text Articles in Physical Sciences and Mathematics

A Newton Root-Finding Algorithm For Estimating The Regularization Parameter For Solving Ill-Conditioned Least Squares Problems, Jodi Mead, Rosemary Renaut Jan 2009

A Newton Root-Finding Algorithm For Estimating The Regularization Parameter For Solving Ill-Conditioned Least Squares Problems, Jodi Mead, Rosemary Renaut

Mathematics Faculty Publications and Presentations

We discuss the solution of numerically ill-posed overdetermined systems of equations using Tikhonov a-priori-based regularization. When the noise distribution on the measured data is available to appropriately weight the fidelity term, and the regularization is assumed to be weighted by inverse covariance information on the model parameters, the underlying cost functional becomes a random variable that follows a X2 distribution. The regularization parameter can then be found so that the optimal cost functional has this property. Under this premise a scalar Newton root-finding algorithm for obtaining the regularization parameter is presented. The algorithm, which uses the singular value …

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Learning On The Fly: Font Free Approaches To Difficult Ocr Problems, Andrew Kae, Erik Learned-Miller Jan 2009

Learning On The Fly: Font Free Approaches To Difficult Ocr Problems, Andrew Kae, Erik Learned-Miller

Erik G Learned-Miller

Despite ubiquitous claims that optical character recog- nition (OCR) is a “solved problem,” many categories of documents continue to break modern OCR software such as documents with moderate degradation or unusual fonts. Many approaches rely on pre-computed or stored charac- ter models, but these are vulnerable to cases when the font of a particular document was not part of the training set, or when there is so much noise in a document that the font model becomes weak. To address these difficult cases, we present a form of iterative contextual modeling that learns character models directly from the document it …

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Robust Recognition Of Documents By Fusing Results Of Word Clusters, Venkat Rasagna, Anand Kumar, C. Jawahar, R. Manmatha Jan 2009

Robust Recognition Of Documents By Fusing Results Of Word Clusters, Venkat Rasagna, Anand Kumar, C. Jawahar, R. Manmatha

R. Manmatha

The word error rate of any optical character recognition system (OCR) is usually substantially below its component or character error rate. This is especially true of Indic languages in which a word consists of many components. Current OCRs recognize each character or word separately and do not take advantage of document level constraints. We propose a document level OCR which incorporates information from the entire document to reduce word error rates. Word images are first clustered using a locality sensitive hashing technique. Individual words are then recognized using a (regular) OCR. The OCR outputs of word images in a cluster …

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Uncontrolled Combustion Of Household Wastes And Vegetation Remains In A Rural Community – Questionnaire Results, Robert Oleniacz, Anna Tomkowicz Jan 2009

Uncontrolled Combustion Of Household Wastes And Vegetation Remains In A Rural Community – Questionnaire Results, Robert Oleniacz, Anna Tomkowicz

Robert Oleniacz

Uncontrolled combustion of household wastes and vegetation remains makes a serious problem referring to the emission of many substances polluting atmosphere, including polychlorinated dibenzo-p-dioxins and dibenzofurans. Combustion of post-use wastes or garbage and burning grasses are also seen as one of the causes of air pollution in larger and larger number of communities in Poland. The awareness of the Polish society referring to this problem and related appearance of different air pollutants, including dioxins and furans, has still been low. It was studied in one of Polish rural communities, based on the results of the questionnaires. In the questionnaire studies …

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The Concept Of The Islands Extraction In Satellite Images Using Mathematical Morphology, Przemysław Kupidura Jan 2009

The Concept Of The Islands Extraction In Satellite Images Using Mathematical Morphology, Przemysław Kupidura

Przemysław Kupidura

The neighborhood is one of the indirect features of the object which may be used in the interpretation of the image. Sometimes, this feature may be essential, what can be shown using an example of islands. According to Oxford Dictionary (Internet edition) island is "a piece of land surrounded by water" so, as we can see, this element of landscape is defined by its neighborhood. The traditional, pixel-based classification is useless in such a case, taking into account only digital numbers of individual pixels. It is impossible to classify islands properly, using this kind of non-contextual algorithms. This paper presents …

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The Morphological Filtering Of The Remote Sensing Images For The Noise Reduction Comparing To Traditional Filters, Przemysław Kupidura, Magdalena Jakubiak Jan 2009

The Morphological Filtering Of The Remote Sensing Images For The Noise Reduction Comparing To Traditional Filters, Przemysław Kupidura, Magdalena Jakubiak

Przemysław Kupidura

The advantages and disadvantages of the traditional (non-morphological) filters are commonly known. Focusing only on disadvantages, it is necessary to mention that most of these filters mainly blur noise over the image, making it less visible. That operation causes depreciation of the amount of information on the image rather than increasing its quality. In recent years there has been a trend to develop more efficient procedures for improving image quality. Theoretically, morphological filters have potential in such usage without possessing the drawbacks of traditional filters. The purpose of this paper is to present the results of an evaluation of the …

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Notes On The Two-Body Problem, Cathy Kessel Jan 2009

Notes On The Two-Body Problem, Cathy Kessel

Cathy Kessel

No abstract provided.

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Effect Of Salts On The Electrospinning Of Poly(Vinyl Alcohol), Jonathan J. Stanger, Nick Tucker, Mark P. Staiger, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Nigel Larsen Jan 2009

Effect Of Salts On The Electrospinning Of Poly(Vinyl Alcohol), Jonathan J. Stanger, Nick Tucker, Mark P. Staiger, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Nigel Larsen

Jonathan J Stanger

Fibres with a diameter in the nanometer range were electrospun from aqueous poly(vinyl alcohol) (PVOH). In order to improve the mass deposition rate and decrease the final fibre diameter salts (NaCl, LiCl, LiBr and LiF) were added to the solution. The aim was to increase the charge density and hence increase the electrostatic forces on the fluid. It was found that with increasing salt concentration the charge density did increase. However the mass deposition rate was found to decrease and the final fibre diameter was found to increase. The decrease in mass deposition rate is explained by considering the concept …

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Effect Of Charge Density On The Taylor Cone In Electrospinning, Jonathan J. Stanger, Nick Tucker, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Mark P. Staiger Jan 2009

Effect Of Charge Density On The Taylor Cone In Electrospinning, Jonathan J. Stanger, Nick Tucker, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Mark P. Staiger

Jonathan J Stanger

A detailed understanding of charge density and its origins during the electrospinning process is desirable for developing new electrospinnable polymer-solvent systems and ensuring mathematical models of the process are accurate. In this work, two different approaches were taken to alter the charge density in order to measure its effect on the Taylor cone, mass deposition rate and initial jet diameter. It was found that an increase in charge density results in a decrease in the mass deposition rate and initial jet diameter. A theory is proposed for this behaviour in that an increase in charge density leads to the tip …

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The Effect Of Electrode Configuration And Substrate Material On The Mass Deposition Rate Of Electrospinning, Jonathan J. Stanger, Nick Tucker, Andrew Wallace, Nigel Larsen, Mark P. Staiger, Roger Reeves Jan 2009

The Effect Of Electrode Configuration And Substrate Material On The Mass Deposition Rate Of Electrospinning, Jonathan J. Stanger, Nick Tucker, Andrew Wallace, Nigel Larsen, Mark P. Staiger, Roger Reeves

Jonathan J Stanger

Poly(vinyl alcohol) (PVOH) was electrospun using different methods to charge the polymer solution. A positive high voltage relative to the collecting electrode significantly increased the fibre deposition rate. Electron microscopy showed that approximately half of the increase in fibre mass was due to thicker fibres being deposited. The current flowing from the grounded electrode was measured to determine the charge carried on the PVOH jet. This showed that for a positive voltage charging condition there is a much larger current and hence more charge carriers generated in the PVOH solution. As a result, more mass is ejected from the Taylor …

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Numerical Solution Of Fuzzy Differential Inclusion By Euler Method, E. Babolian, Saeid Abbasbandy, M. Alavi Jan 2009

Numerical Solution Of Fuzzy Differential Inclusion By Euler Method, E. Babolian, Saeid Abbasbandy, M. Alavi

Saeid Abbasbandy

In this paper we introduce Euler method for solving one dimensional fuzzy differential inclusions. Fuzzy reachable set can be approximated by Euler method with complete analysis.

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Fixed Point Method For Solving Fuzzy Nonlinear Equations, Saeid Abbasbandy, Ahmad Jafarian Jan 2009

Fixed Point Method For Solving Fuzzy Nonlinear Equations, Saeid Abbasbandy, Ahmad Jafarian

Saeid Abbasbandy

In this paper, we propose the numerical soluiton for a fuzzy nonlinear equation by fixed point method.

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The Logic Of Bailout Strategies, Rudolf Kaehr Jan 2009

The Logic Of Bailout Strategies, Rudolf Kaehr

Rudolf Kaehr

Some thoughts about/of the logic, blend, chiasm and diamond of bailout strategies. Eliciting aspects of the maxim: “Without insurrection, no resurrection".

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Diamond Semiotic Short Studies, Rudolf Kaehr Jan 2009

Diamond Semiotic Short Studies, Rudolf Kaehr

Rudolf Kaehr

A collection of papers on semiotics, polycontexturality and diamond theory

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Financial Distress And Idiosyncratic Volatility: An Empirical Investigation, Lorán Chollete, Jing Chen, Rina Ray Jan 2009

Financial Distress And Idiosyncratic Volatility: An Empirical Investigation, Lorán Chollete, Jing Chen, Rina Ray

Lorán Chollete

No abstract provided.

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Financial Implications Of Extreme And Rare Events, Lorán Chollete, Dwight Jaffee Jan 2009

Financial Implications Of Extreme And Rare Events, Lorán Chollete, Dwight Jaffee

Lorán Chollete

No abstract provided.

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Dependence Of Macro Variables In The Us Economy, Lorán Chollete, Cathy Ning Jan 2009

Dependence Of Macro Variables In The Us Economy, Lorán Chollete, Cathy Ning

Lorán Chollete

No abstract provided.

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Modeling International Financial Returns With A Multivariate Regime-Switching Copula, Lorán Chollete, Andreas Heinen, Alfonso Valdesogo Jan 2009

Modeling International Financial Returns With A Multivariate Regime-Switching Copula, Lorán Chollete, Andreas Heinen, Alfonso Valdesogo

Lorán Chollete

No abstract provided.

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An Elementary Introduction To The Homotopy Perturbation Method, Ji-Huan He Jan 2009

An Elementary Introduction To The Homotopy Perturbation Method, Ji-Huan He

Ji-Huan He

This paper is an elementary introduction to the concepts of the homotopy perturbation method. Particular attention is paid to giving an intuitive grasp for the solution procedure throughout the paper.

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Soliton Perturbation, Ji-Huan He Jan 2009

Soliton Perturbation, Ji-Huan He

Ji-Huan He

Glossary Soliton A soliton is a nonlinear pulse-like wave that can exist in some nonlinear systems. The isolated wave can propagate without dispersing its energy over a large region of space; collision of two solitons leads to unchanged forms, solitons also exhibit particlelike properties. Soliton perturbation theory The soliton perturbation theory is used to study the solitons that are governed by the various nonlinear equations in presence of the perturbation terms. Homotopy perturbation method The homotopy perturbationmethod is a useful tool to the search for solitons without the requirement of presence of small perturbations. In this method, a homotopy is …

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Solitons And Compactons, Ji-Huan He, Shun-Dong Zhu Jan 2009

Solitons And Compactons, Ji-Huan He, Shun-Dong Zhu

Ji-Huan He

Article Outline Glossary Definition of the Subject Introduction Solitons Compactons Generalized Solitons and Compacton-like Solutions Future Directions Cross References Bibliography Glossary Soliton A soliton is a stable pulse-like wave that can exist in some nonlinear systems. The soliton, after a collision with another soliton, eventually emerges unscathed. Compacton A compacton is a special solitary traveling wave that, unlike a soliton, does not have exponential tails. Generalized soliton A generalized soliton is a soliton with some free parameters. Generally a generalized soliton can be expressed by exponential functions. 8458 S Solitons and Compactons Compacton-like solution A compcton-like solution is a special …

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Ore: A Framework To Measure Organizational Risk During Information Systems Evolution, Aditya Agrawal, Gavin Finnie, Padmanabhan Krishnan Jan 2009

Ore: A Framework To Measure Organizational Risk During Information Systems Evolution, Aditya Agrawal, Gavin Finnie, Padmanabhan Krishnan

Padmanabhan Krishnan

Information systems (IS) change initiatives often represent the single largest investment (and therefore risk) for large corporations, yet there exist few management frameworks in the literature to help decision makers measure organizational risk in a balanced manner during this organization-wide change process. The ORE framework has been developed as a design science artifact based on the Leavitt diamond paradigm as a multi-criteria, relative risk, condition consequence, management decision framework enabling decision makers to calculate and compare risk evolution at fixed points of the change cycle and make structured and balanced risk mitigation decisions. In this chapter the principles, architecture and …

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Multiobjective Optimization Of An Industrial Lpg Thermal Cracker Using A First Principles Model, Reza Nabavi, G.P Rangaiah, Ali Niaei, Dariush Salari Jan 2009

Multiobjective Optimization Of An Industrial Lpg Thermal Cracker Using A First Principles Model, Reza Nabavi, G.P Rangaiah, Ali Niaei, Dariush Salari

Seyed Reza nabavi

Thermal cracking of hydrocarbons in the presence of steam is the most important process for the production of ethylene and propylene, which are the raw materials for many petrochemicals. In this work, multiobjective optimization (MOO) of an industrial LPG (liquefied petroleum gas containing mainly propane and butane) thermal cracker is studied using the elitist nondominated sorting genetic algorithm adapted with the jumping gene operator, NSGA-II-aJG. A first principles model based on free radical mechanism for LPG thermal cracking is employed for optimization. Several bi- and triobjective optimization problems are solved; these problems involved maximization of annual ethylene/propylene production, selectivity and …

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The Fundamentals Of Local Fractional Derivative Of The One-Variable Non-Differentiable Functions, Yang Xiaojun Jan 2009

The Fundamentals Of Local Fractional Derivative Of The One-Variable Non-Differentiable Functions, Yang Xiaojun

Xiao-Jun Yang

Based on the theory of Jumarie’s fractional calculus, local fractional derivative is modified in detail and its fundamentals of local fractional derivative are proposed in this paper. The uniqueness of local fractional derivative is obtained and the Rolle’s theorem, the mean value theorem, the Cauchy’s generalized mean value theorem and the L’Hospital’s rules are proved.

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Local Fractional Newton’S Method Derived From Modified Local Fractional Calculus, Yang Xiao-Jun Jan 2009

Local Fractional Newton’S Method Derived From Modified Local Fractional Calculus, Yang Xiao-Jun

Xiao-Jun Yang

A local fractional Newton’s method, which is derived from the modified local fractional calculus , is proposed in the present paper. Its iterative function is obtained and the convergence of the iterative function is discussed. The comparison between the classical Newton iteration and the local fractional Newton iteration has been carried out. It is shown that the iterative value of the local fractional Newton method better approximates the real-value than that of the classical one.

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Preparation Of Wo3 Nanoparticles Using Cetyl Trimethyl Ammonium Bromide Supermolecular Template, Nilofar Asim, S. Radiman, M.A. Bin Yarmo Jan 2009

Preparation Of Wo3 Nanoparticles Using Cetyl Trimethyl Ammonium Bromide Supermolecular Template, Nilofar Asim, S. Radiman, M.A. Bin Yarmo

Nilofar Asim

WO3 is one of the most interested metal oxides because of its application as catalysts, sensors, electrochromic devices, ceramic, solar cell, pigments and so on. More investigation is needed to find the good and low cost method for preparation of WO3 nanoparticles with uniform morphology and narrow distribution using a surfactant mediated method. Approach: In this study, the synthesis of WO3 nanoparticles was accomplished using a cationic surfactant (cetyl trimethyl ammonium bromide) as the organic supermolecular template and WCl6 and NH4 OH as the inorganic precursor and counter ion source, respectively. The effects of reaction temperature and surfactant concentration in …

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Uniqueprimer - A Web Utility For Design Of Specific Pcr Primers And Probes, Torstein Tengs Jan 2009

Uniqueprimer - A Web Utility For Design Of Specific Pcr Primers And Probes, Torstein Tengs

Dr. Torstein Tengs

We have developed a web-based tool for design of specific PCR primers and probes. The program allows you to enter primer sequence information as well as an optional probe, and sequence similarity searches (MegaBLAST) will be performed to see if the sequences match the same sequence entry in the specified database. If primers (and probe) match, this will be reported. The program can handle overlapping amplicons, amplification from a single primer, ambiguous bases and other problematic cases.

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Computational Method For Inferring Objective Function Of Glycerol Metabolism In Klebsiella Pneumoniae, Zhaohua Gong, Chongyang Liu, Enmin Feng, Qingrui Zhang Jan 2009

Computational Method For Inferring Objective Function Of Glycerol Metabolism In Klebsiella Pneumoniae, Zhaohua Gong, Chongyang Liu, Enmin Feng, Qingrui Zhang

Chongyang Liu

Flux balance analysis (FBA) is an effective tool in the analysis of metabolic network. It can predict the flux distribution of engineered cells, whereas the accurate prediction depends on the reasonable objective function. In this work, we propose two nonlinear bilevel programming models on anaerobic glycerol metabolism in Klebsiella pneumoniae (K. pneumoniae) for 1,3-propanediol (1,3-PD) production. One intends to infer the metabolic objective function, and the other is to analyze the robustness of the objective function. In view of the models’ characteristic an improved genetic algorithm is constructed to solve them, where some techniques are adopted to guarantee all chromosomes …

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Modelling And Optimal Control For Nonlinear Multistage Dynamical System Of Microbial Fed-Batch Culture, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin Jan 2009

Modelling And Optimal Control For Nonlinear Multistage Dynamical System Of Microbial Fed-Batch Culture, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin

Chongyang Liu

In this paper, we propose a new controlled multistage system to formulate the fed-batch culture process of glycerol bio-dissimilation to 1,3-propanediol (1,3-PD) by regarding the feeding rate of glycerol as a control function. Compared with the previous systems, this system doesn’t take the feeding process as an impulsive form, but a time-continuous process, which is much closer to the actual culture process. Some properties of the above dynamical system are then proved. To maximize the concentration of 1,3-PD at the terminal time, we develop an optimal control model subject to our proposed controlled multistage system and continuous state inequality constraints. …

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Optimal Control And Properties Of Nonlinear Multistage Dynamical System For Planning Horizontal Well Paths, Zhaohua Gong, Chongyang Liu, Enmin Feng Jan 2009

Optimal Control And Properties Of Nonlinear Multistage Dynamical System For Planning Horizontal Well Paths, Zhaohua Gong, Chongyang Liu, Enmin Feng

Chongyang Liu

The goal of planning a horizontal well path is to obtain a trajectory that arrives at a given target subject to various constraints. In this paper, the optimal control problem subject to a nonlinear multistage dynamical system (NMDS) for horizontal well paths is investigated. Some properties of the multistage system are proved. In order to derive the optimality conditions, we transform the optimal control problem into one with control constraints and inequality-constrained trajectories by defining some functions. The properties of these functions are then discussed and optimality conditions for optimal control problem are also given. Finally, an improved simplex method …

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