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142 results on '"JEFFREY, D. J."'

1. Bernoulli’s Problem and Maple

Author

Ayoub, T. J., Basu, K., Jeffrey, D. J., Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Corless, Robert M., editor, Gerhard, Jürgen, editor, and Kotsireas, Ilias S., editor

Published
2021
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2. Unimodal sequences show Lambert W is Bernstein

Author

Kalugin, G. A. and Jeffrey, D. J.

Subjects
Mathematics - Classical Analysis and ODEs, 11B83
Abstract

We consider a sequence of polynomials appearing in expressions for the derivatives of the Lambert W function. The coefficients of each polynomial are shown to form a positive sequence that is log-concave and unimodal. This property implies that the positive real branch of the Lambert W function is a Bernstein function., Comment: 6 pages

Published
2010

3. Conjecture concerning a completely monotonic function

Author

Shemyakova, E., Khashin, S. I., and Jeffrey, D. J.

Subjects
Mathematics - Classical Analysis and ODEs, 00A69
Abstract

Based on a sequence of numerical computations, a conjecture is presented regarding the class of functions $H(x;a)=\exp(a)-(1+a/x)^x$, and the open problem of determining the values of $a$ for which the functions are completely monotonic with respect to $x$. The critical value of $a$ is determined here to sufficient accuracy to show that it is not a simple symbolic quantity., Comment: accepted for publication in Computers and Mathematics with Applications

Published
2010

5. Diminished Upper Bounds on the Unification Mass Scales for Heavy Higgs Boson Masses

Author

Elias, V., Homayouni, S., and Jeffrey, D. J.

Subjects
High Energy Physics - Theory, High Energy Physics - Phenomenology
Abstract

We consider dominant 3-, 4-, and 5-loop contributions to $\lambda$, the quartic scalar coupling-constant's $\beta$-function in the Standard Model. We find that these terms accelerate the evolution of $\lambda$ to nonperturbative values, thereby lowering the unification bound for which scalar-couplings are still perturbative. We also find that these higher order contributions imply a substantial lowering of $\lambda$ itself before the anticipated onset of nonperturbative physics in the Higgs sector.

Published
2005
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6. Computation of Some Integer Sequences in Maple

Author

Fan, W. L., Jeffrey, D. J., Postma, Erik, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Gerdt, Vladimir P., editor, Koepf, Wolfram, editor, Seiler, Werner M., editor, and Vorozhtsov, Evgenii V., editor

Published
2017
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9. Series Transformations to Improve and Extend Convergence

Author

Kalugin, G. A., Jeffrey, D. J., Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Gerdt, Vladimir P., editor, Koepf, Wolfram, editor, Mayr, Ernst W., editor, and Vorozhtsov, Evgenii V., editor

Published
2010
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10. A Knowledge Repository for Indefinite Integration Based on Transformation Rules

Author

Rich, A. D., Jeffrey, D. J., Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Goebel, Randy, editor, Siekmann, Jörg, editor, Wahlster, Wolfgang, editor, Carette, Jacques, editor, Dixon, Lucas, editor, Coen, Claudio Sacerdoti, editor, and Watt, Stephen M., editor

Published
2009
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12. Hierarchical Representations with Signatures for Large Expression Management

Author

Zhou, Wenqin, Carette, J., Jeffrey, D. J., Monagan, M. B., Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Carbonell, Jaime G., editor, Siekmann, Jörg, editor, Calmet, Jacques, editor, Ida, Tetsuo, editor, and Wang, Dongming, editor

Published
2006
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13. Stokes-Flow Problem Solved Using Maple

Author

Pratibha, Jeffrey, D. J., Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Sunderam, Vaidy S., editor, van Albada, Geert Dick, editor, Sloot, Peter M. A., editor, and Dongarra, Jack, editor

Published
2005
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14. An Algebraic Method for Analyzing Open-Loop Dynamic Systems

Author

Zhou, W., Jeffrey, D. J., Reid, G. J., Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Sunderam, Vaidy S., editor, van Albada, Geert Dick, editor, Sloot, Peter M. A., editor, and Dongarra, Jack, editor

Published
2005
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15. The Wright ω Function

Author

Corless, Robert M., Jeffrey, D. J., Goos, G., editor, Hartmanis, J., editor, van Leeuwen, J., editor, Carbonell, J. G., editor, Siekmann, J., editor, Calmet, Jacques, editor, Benhamou, Belaid, editor, Caprotti, Olga, editor, Henocque, Laurent, editor, and Sorge, Volker, editor

Published
2002
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28. Particle migration in suspensions by thermocapillary or electrophoretic motion

Author

Acrivos, A, Jeffrey, D. J, and Saville, D. A

Subjects
Fluid Mechanics And Heat Transfer
Abstract

Two problems of similar mathematical structure are presented: the thermocapillary motion of bubbles and the electrophoresis of colloidal particles. For both problems, it is shown that in a cloud of n particles surrounded by an infinite expanse of fluid, the velocity of each sphere under creeping flow conditions is equal to the velocity of an isolated particle, unchanged by interactions between the particles. However, when the cloud fills a container, conservation of mass shows that this result cannot continue to hold, and the average translational velocity must be calculated subject to a constraint on the mass flux. It is concluded that the average thermocapillary or electrophoretic translational velocity of a particle in the cloud is related to the effective conductivity of the cloud over the whole range of particle volume fractions, provided that the particles are identical, non-conducting and, for the thermocapillary problem, inviscid.

Published
1990

35. D-dimensional Bose gases and the Lambert W function

Author

Valluri, Sree Ram, Tanguay, J, Gil, M, Jeffrey, D J, Valluri, Sree Ram, Tanguay, J, Gil, M, and Jeffrey, D J

Abstract

The applications of the Lambert W function (also known as the W function) to D-dimensional Bose gases are presented. We introduce two sets of families of logarithmic transcendental equations that occur frequently in thermodynamics and statistical mechanics and present their solution in terms of the W function. The low temperature T behavior of free ideal Bose gases is considered in three and four dimensions. It is shown that near condensation in four dimensions, the chemical potential μ and pressure P can be expressed in terms of T through the W function. The low T behavior of one- and two-dimensional ideal Bose gases in a harmonic trap is studied. In 1D, the W function is used to express the condensate temperature, TC, in terms of the number of particles N; in 2D, it is used to express μ in terms of T . In the low T limit of the 1D hard-core and the 3D Bose gas, T can be expressed in terms of P and μ through the W function. Our analysis allows for the possibility to consider μ, T , and P as complex variables. The importance of the underlying logarithmic structure in ideal quantum gases is seen in the polylogarithmic and W function expressions relating thermodynamic variables such as μ, T , and P.

Published
2010

42. Hierarchical Representations with Signatures for Large Expression Management.

Author

Wenqin Zhou, Carette, J., Jeffrey, D. J., Monagan, M. B., Calmet, Jacques, Ida, Tetsuo, and Dongming Wang

Abstract

We describe a method for managing large expressions in symbolic computations which combines a hierarchical representation with signature calculations. As a case study, the problem of factoring matrices with non-polynomial entries is studied. Gaussian Elimination is used. Results on the complexity of the approach together with benchmark calculations are given. Keywords: Hierarchical Representation, Veiling Strategy, Signature, Zero Test, Large Expression Management, Symbolic LU Decomposition, Time Complexity. [ABSTRACT FROM AUTHOR]

Published
2006
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44. Stokes-Flow Problem Solved Using Maple.

Author

Sunderam, Vaidy S., Albada, Geert Dick van, Sloot, Peter M. A., Dongarra, Jack J., Pratibha, and Jeffrey, D. J.

Abstract

An unusual boundary-value problem that arises in a fluid-mechanical application is solved to high precision, as a challenge problem in scientific computation. A second-order differential equation must be solved on (0,∞ ), subject to boundary conditions that specify only the asymptotic behaviour of the solution at the two ends of the solution domain. In addition, the solution is required to high accuracy to settle a conjecture made by previous authors. The solution is obtained by computing multiple series solutions using Maple. [ABSTRACT FROM AUTHOR]

Published
2005
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45. An Algebraic Method for Analyzing Open-Loop Dynamic Systems.

Author

Sunderam, Vaidy S., Albada, Geert Dick van, Sloot, Peter M. A., Dongarra, Jack J., Zhou, W., Jeffrey, D. J., and Reid, G. J.

Abstract

This paper reports on the results of combining the Maple packages Dynaflex and RifSimp. The Dynaflex package has been developed to generate the governing dynamical equations for mechanical systems; the RifSimp package has been developed for the symbolic analysis of differential equations. We show that the output equations from Dynaflex can be converted into a form which can be analyzed by RifSimp. Of particular interest is the ability of RifSimp to split a set of differential equations into different cases; each case corresponds to a different set of assumptions, and under some sets of assumptions there are significant simplifications. In order to allow RifSimp to conduct its analysis, the governing equations must be converted from trigonometric form into a polynomial form. After this is done, RifSimp can analyze the system and present its results either graphically, or in list form. The mechanical systems considered are restricted to open-loop systems, because at present, closed-loop systems require too much computation by RifSimp to permit analysis. Keywords:Dynaflex, RifSimp, Case Splitting, Symbolic Simplification, Graph Theory, Computer Algebra. [ABSTRACT FROM AUTHOR]

Published
2005
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46. AN EXPLORATION OF HOMOTOPY SOLVING IN MAPLE.

Author

HAZAVEH, K., JEFFREY, D. J., REID, G. J., WATT, S. M., and WITTKOPF, A. D.

Subjects
HOMOTOPY theory, CONTINUOUS functions, DEFORMATIONS (Mechanics), POLYNOMIALS, PARAMETER estimation, NUMBER theory
Published
2003

48. The pressure moments for two rigid spheres in low-Reynolds-number flow

Author

Jeffrey, D. J., Morris, J. F., Brady, J. F., Jeffrey, D. J., Morris, J. F., and Brady, J. F.

Abstract

The pressure moment of a rigid particle is defined to be the trace of the first moment of the surface stress acting on the particle. A Faxén law for the pressure moment of one spherical particle in a general low-Reynolds-number flow is found in terms of the ambient pressure, and the pressure moments of two rigid spheres immersed in a linear ambient flow are calculated using multipole expansions and lubrication theory. The results are expressed in terms of resistance functions, following the practice established in other interaction studies. The osmotic pressure in a dilute colloidal suspension at small Péclet number is then calculated, to second order in particle volume fraction, using these resistance functions. In a second application of the pressure moment, the suspension or particle-phase pressure, used in two-phase flow modeling, is calculated using Stokesian dynamics and results for the suspension pressure for a sheared cubic lattice are reported.

Published
1993

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