196,024 research outputs found
A contour integral approach to the computation of invariant pairs
No full textWe study some aspects of the invariant pair problem for matrix polynomials, as introduced by Betcke and Kressner [3] and by Beyn and Thümmler [6]. Invariant pairs extend the notion of eigenvalue–eigenvector pairs, providing a counterpart of invariant subspaces for the nonlinear case. We compute formulations for the condition numbers and the backward error for invariant pairs and solvents. We then adapt the Sakurai–Sugiura moment method [1] to the computation of invariant pairs, including some classes of problems that have multiple eigenvalues. Numerical refinement via a variant of Newton's method is also studied. Furthermore, we investigate the relation between the matrix solvent problem and the triangularization of matrix polynomials
On the Moser- and super-reduction algorithms of systems of linear differential equations and their complexity
No full textAbstractThe notion of irreducible forms of systems of linear differential equations with formal power series coefficients as defined by Moser [Moser, J., 1960. The order of a singularity in Fuchs’ theory. Math. Z. 379–398] and its generalisation, the super-irreducible forms introduced in Hilali and Wazner [Hilali, A., Wazner, A., 1987. Formes super-irréductibles des systèmes différentiels linéaires. Numer. Math. 50, 429–449], are important concepts in the context of the symbolic resolution of systems of linear differential equations [Barkatou, M., 1997. An algorithm to compute the exponential part of a formal fundamental matrix solution of a linear differential system. Journal of App. Alg. in Eng. Comm. and Comp. 8 (1), 1–23; Pflügel, E., 1998. Résolution symbolique des systèmes différentiels linéaires. Ph.D. Thesis, LMC-IMAG; Pflügel, E., 2000. Effective formal reduction of linear differential systems. Appl. Alg. Eng. Comm. Comp., 10 (2) 153–187]. In this paper, we reduce the task of computing a super-irreducible form to that of computing one or several Moser-irreducible forms, using a block-reduction algorithm. This algorithm works on the system directly without converting it to more general types of systems as needed in our previous paper [Barkatou, M., Pflügel, E., 2007. Computing super-irreducible forms of systems of linear differential equations via Moser-reduction: A new approach. In: Proceedings of ISSAC’07. ACM Press, Waterloo, Canada, pp. 1–8]. We perform a cost analysis of our algorithm in order to give the complexity of the super-reduction in terms of the dimension and the Poincaré-rank of the input system. We compare our method with previous algorithms and show that, for systems of big size, the direct block-reduction method is more efficient
On some overdetermined free boundary problems
No full textThis paper deals with some free boundary problems for the Laplacian operator. We first give sufficient conditions of existence of free boundaries. Then combining the maximum principle to the monotonicity of the mean curvature, we will prove a symmetry result in the case where the source term is constant. All the results obtained here can be extended to more general divergence operators.
References D. Bucur and J.P. Zolesio : N-dimensional shape optimization under capacitary constraints, J. Diff. Eq., 123-2, 1995, 504--522. D. Chenais : Sur une famille de varietes a bord lipschitziennes, application a un probleme d'identification de domaine, Ann. Inst. Fourier, 4-27, 1977, 201--231. E. DiBenditto : local regularity of weak solutions of degenerate elliptic equations, Nonlinear Analysis, 7, 1983, 827--850. B. Gustafsson and H. Shahgholian : Existence and geometric properties of solutions of a free boundary problem in potential theory, J. fur die Reine und Ang. Math. 473, 1996, 137--179. A. Henrot and M. Pierre : Variation et optimisation de formes, une analyse geometrique, MathÈmatiques and Applications, 48, (2005), SMAI Springer C. Huang and D. Miller : Domain functionals and exit times for Brownian motion. Proc. Amer. Math. Soc. 130(3), 2001, 825--831. K. K. J. Kinateder P. Mcdonald : Hypersurfaces in and the variance of times for Brownian motion. Proc. Amer. Math. Soc. 125(8), 1997, 2453--2462. J. L. Lewis : Regularity of the derivatives of solutions to certain degenerate elliptic equations, Indiana Univ. Math. J., 32, 1983, 849--858. G. M. Liberman : Boundary regularity for solutions of degenerate elliptic equations, Nonlinear Analysis, 12, 1988, 1203--1219. F. Murat and J. Simon: Quelques resultats sur le controle par un domaine geometrique, Publ. du labo. d'Anal. Num. Paris VI, 1974, 1--46 A. D. Alexandrov: Uniquness theorems for surfaces in large I, II, Amer. Soc. Trans. 31, 1962, 341--388. O. Pironneau : Optimal shape design for elliptic systems, Springer Series in Computational Physics, 1984, Springer, New York. H. Shahgholian : Existence of Quadrature Surfaces for Positive Measures with Finite Support, Potential Analysis, 3, 1994, 245--255. J. Sokolowski et J. P. Zolesio : Introduction to shape optimization : shape sensitity analysis, Springer Series in Computational Mathematics, 10, 1992, Springer, Berlin. P. Tolksdorf (1983) On the Dirichlet problem for quasilinear equations in domains with conical boundary points, Comm. Partial Differential Equations, 8(7), 1983, 773--817. M. Barkatou, D. Seck and I. Ly: An existence result for a quadrature surface free boundary problem, Cent. Eur. Jou. Math. 3(1), 2005, 39--57. M. Barkatou: Some geometric properties for a class of non Lipschitz-domains, New York J. Math. 8, 2002, 189--213. http://nyjm.albany.edu:8000/j/2002/8-13.html D. Bucur and P. Trebeschi : Shape Optimization Problems Governed by Nonlinear State Equations, Proc. Roy. Soc. Edinburgh , 128A, 1998, 945--96
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Computer Algebra Tools for Handling Ordinary Differential Equations (CATHODE 2) Han sur Lesse Workshop - Extended Abstracts
No full texts Esprit Working Group 24490 Workshop from 1st to 5th of September 1997 Calcul Symbolique sur Ordinateur (CSO) Facult'e des Sciences, Universit'e Libre de Bruxelles. This document contains the Extended Abstracts which have been sent by the speakers before the CATHODE 2 Workshop in Han sur Lesse. It will be distributed to the participants at the beginning of the Workshop. It is available from the CSO 1 WEB main page at http://cso.ulb.ac.be in html form. Jean-Louis Colot 27th August, 1997 Contents 1 Electronic mail of the participants 3 2 ISOLDE : a package for Integrating Systems of Linear Differential Equations. M. A. Barkatou and E. Pflugel 5 3 Computation of differential galois groups. F. Beukers 10 4 Solution for discharges. L. Brenig, J .Buffet, J. Thomann, A. Sengier and J.-L. Colot 12 5 Basic algorithms for completely reducible linear ordinary differential operators. M. Bronstein 19 6 An automatic algorithm for computing the Taylor expansion solution of dynamical systems ..
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
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