TY - JOUR
TI - SINGULAR VALUE REASSIGNMENT WITH LOW RANK MATRICES (DRAFT: June 11, 2004)
AU - Chu, Delin
AU - Chu, Moody
DA - 2004///
PY - 2004///
UR - http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.61.6384
ER -
TY - JOUR
TI - SINGULAR VALUE REASSIGNMENT WITH LOW RANK MATRICES
AU - Chu, Delin
AU - Chu, Moody
DA - 2004///
PY - 2004///
UR - http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.71.8290
ER -
TY - JOUR
TI - On inverse quadratic eigenvalue problems with partially prescribed eigenstructure
AU - Chu, M.T.
AU - Kuo, Y.-C.
AU - Lin, W.-W.
T2 - SIAM Journal on Matrix Analysis and Applications
AB - The inverse eigenvalue problem of constructing real and symmetric square matrices M, C, and K of size $n \times n$ for the quadratic pencil $Q(\lambda) = \lambda^2 M + \lambda C + K$ so that $Q(\lambda)$ has a prescribed subset of eigenvalues and eigenvectors is considered. This paper consists of two parts addressing two related but different problems. The first part deals with the inverse problem where M and K are required to be positive definite and semidefinite, respectively. It is shown via construction that the inverse problem is solvable for any k, given complex conjugately closed pairs of distinct eigenvalues and linearly independent eigenvectors, provided $k \leq n$. The construction also allows additional optimization conditions to be built into the solution so as to better refine the approximate pencil. The eigenstructure of the resulting $Q(\lambda)$ is completely analyzed. The second part deals with the inverse problem where M is a fixed positive definite matrix (and hence may be assumed to be the identity matrix $I_n$). It is shown via construction that the monic quadratic pencil $Q(\lambda)=\lambda^2 I_n + \lambda C + K$, with $n + 1$ arbitrarily assigned complex conjugately closed pairs of distinct eigenvalues and column eigenvectors which span the space $\mathbb{C}^n$, always exists. Sufficient conditions under which this quadratic inverse eigenvalue problem is uniquely solvable are specified.
DA - 2004///
PY - 2004///
DO - 10.1137/S0895479803404484
VL - 25
IS - 4
SP - 995-1020
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-8344269351&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Early termination in Shoup's algorithm for the minimum polynomial of an algebraic
AU - Eberly, Wayne
AU - Kaltofen, Erich
DA - 2004///
PY - 2004///
ER -
TY - CONF
TI - Design of a Detection Signal for Fault Detection and Model Identification on Systems with Multiple Delays
AU - Drake, K.
AU - Campbell, S.L.
T2 - American Society of Naval Engineers Day
C2 - 2004/6/28/
C3 - Proceedings of the American Society of Naval Engineers Day 2004
CY - Alexandria, VA
DA - 2004/6/28/
PY - 2004/6/28/
ER -
TY - CONF
TI - ODE and DAE integrators in Scicos environment
AU - Najafi, M.
AU - Nikoukhah, R.
AU - Campbell, S.L.
T2 - IASTED International Conference on Applied Simulation and Modeling
A2 - Hamza, M.H.
C2 - 2004///
C3 - Proceedings of the IASTED International Conference on Applied Simulation and Modelling and Simulation : June 28-30, 2004, Rhodes, Greece
CY - Rhodes, Greece
DA - 2004///
PY - 2004/6/28/
PB - ACTA Press
SN - 0889863970 9780889863972
ER -
TY - MGZN
TI - Accurate eigenvalues for fast trains
AU - Ipsen, I.C.F.
T2 - SIAM News
DA - 2004/11//
PY - 2004/11//
VL - 37
SP - 1–2
M1 - 9
ER -
TY - JOUR
TI - Visualizing symmetry of knots by using program LinKnot, Symmetry: Art and Science
AU - Jablan, S.
AU - Sazdanovic, R.
T2 - The Journal of ISIS-Symmetry
DA - 2004///
PY - 2004///
VL - 1-4
SP - 106–110
ER -
TY - CONF
TI - Modularity in Medieval Persian Mosaics: Textual, Empirical, Analytical and Theoretical Considerations, Bridges
AU - Sarhangi, R.
AU - Jablan, S.
AU - Sazdanovic, R.
C2 - 2004///
C3 - Mathematical Connections in Art, Music and Science, Conference Proceedings
DA - 2004///
SP - 281–293
ER -
TY - JOUR
TI - Hyperbolic Tessellations by tess
AU - Sazdanovic, R.
AU - Sremcević, M.
T2 - Symmetry: Art and Science (The Quarterly of ISIS Symmetry)
DA - 2004///
PY - 2004///
SP - 1–4 226–229
ER -
TY - JOUR
TI - Golden Fields, Generalized Fibonacci Sequences, and Chaotic Matrices
AU - Kappraff, J.
AU - Jablan, S.
AU - Adamson, G.W.
AU - Sazdanović, R.
T2 - Forma
DA - 2004///
PY - 2004///
VL - 19
IS - 4
SP - 367–387
ER -
TY - JOUR
TI - Discovering symmetry of knots by using program LinKnot
AU - Jablan, S.
AU - Sazdanovic, R.
T2 - The Journal of ISIS-Symmetry
DA - 2004///
PY - 2004///
VL - 1-4
SP - 102–106
ER -
TY - CONF
TI - Twisted modules over lattice vertex algebras
AU - Bakalov, Bojko
AU - Kac, Victor G.
T2 - Proceedings of the Fifth International Workshop
A2 - Doebner, H.-D.
A2 - Dobrev, V.K.
AB - For any integral lattice $Q$, one can construct a vertex algebra $V_Q$ called a lattice vertex algebra. If $\sigma$ is an automorphism of $Q$ of finite order, it can be lifted to an automorphism of $V_Q$. In this paper we classify the irreducible $\sigma$-twisted $V_Q$-modules. We show that the category of $\sigma$-twisted $V_Q$-modules is a semisimple abelian category with finitely many isomorphism classes of simple objects.
C2 - 2004/7//
C3 - Lie Theory and Its Applications in Physics V
DA - 2004/7//
DO - 10.1142/9789812702562_0001
SP - 3–26
PB - World Scientific Publishing Company
SN - 9789812389367 9789812702562
UR - http://dx.doi.org/10.1142/9789812702562_0001
ER -
TY - CONF
TI - From Concept to Real-time Implementation: POD Based Reduced Order Control of a Cantilever Beam
AU - Tran, H.
AU - Lewis, B.M.
T2 - 16th International Symposium on Mathematical Theory of Networks and Systems(MTNS 2004)
A2 - De Moor, B.
A2 - Motmans, Bart
A2 - Willems, J.
A2 - Van Dooren, Paul
A2 - Blondel, Vincent
C2 - 2004///
C3 - Proceedings of the 16th International Symposium on Mathematical Theory of Networks and Systems (MTNS 2004)
CY - Catholic University of Leuven (K.U.Leuven-Belgium)
DA - 2004///
PY - 2004/7/5/
ER -
TY - CONF
TI - Analysis of spline based auxiliary signal design for failure detection in delay systems
AU - Campbell, SL
AU - Drake, K.
AU - Nikoukhah, R.
T2 - SMC '03 2003IEEE International Conference on Systems, Man and Cybernetics
AB - In an active approach for model detection and its use in failure detection, an auxiliary control is applied in order to assist in model identification. An active approach for robust multi-model identification and failure detection in the presence of disturbances over possibly short time intervals has been introduced. Previous papers extended the original design procedure to problems with several delays and additive noise. The infinite dimensional delay problem was approximated by a finite dimensional system without delays and numerical examples were worked. The numerical examples seemed to converge better than was expected. In this paper we explain that convergence. In addition we discuss the extension of the previous results for delay systems with additive noise to those with small model uncertainties and explain why this additional assumption of small uncertainty, which was not present in the case without delays, is now needed for the analysis.
C2 - 2004/5/25/
C3 - SMC'03 Conference Proceedings. 2003 IEEE International Conference on Systems, Man and Cybernetics. Conference Theme - System Security and Assurance (Cat. No.03CH37483)
DA - 2004/5/25/
DO - 10.1109/icsmc.2003.1244267
PB - IEEE
SN - 0780379527
UR - http://dx.doi.org/10.1109/icsmc.2003.1244267
DB - Crossref
ER -
TY - CONF
TI - Direct transcription solution of inequality constrained optimal control problems
AU - Betts, J.T.
AU - Campbell, S.L.
AU - Engelsone, A.
T2 - Proceedings of the 2004 American Control Conference
AB - Direct transcription is a popular way to solve the complex optimal control problems that arise in industry. With a direct transcription approach, the problem is fully discretized and then the discrete problem is solved numerically. Recently, it has been shown that the theory for direct transcription differs in several key ways from the theory for other approaches. These differences have implications for numerical algorithms and the interpretation of solutions to practical problems. This paper examines some of those differences.
C2 - 2004///
C3 - Proceedings of the 2004 American Control Conference
DA - 2004///
DO - 10.23919/acc.2004.1386809
PB - IEEE
SN - 0780383354
UR - http://dx.doi.org/10.23919/acc.2004.1386809
DB - Crossref
ER -
TY - JOUR
TI - Deeper Inside PageRank
AU - Langville, Amy
AU - Meyer, Carl
T2 - Internet Mathematics
AB - This paper serves as a companion or extension to the "Inside PageRank" paper by Bianchini et al. [Bianchini et al. 03]. It is a comprehensive survey of all issues associated with PageRank, covering the basic PageRank model, available and recommended solution methods, storage issues, existence, uniqueness, and convergence properties, possible alterations to the basic model, suggested alternatives to the traditional solution methods, sensitivity and conditioning, and finally the updating problem. We introduce a few new results, provide an extensive reference list, and speculate about exciting areas of future research.
DA - 2004/1/1/
PY - 2004/1/1/
DO - 10.1080/15427951.2004.10129091
VL - 1
IS - 3
SP - 335-380
J2 - UINM
LA - en
OP -
SN - 1542-7951
UR - http://dx.doi.org/10.1080/15427951.2004.10129091
DB - Crossref
ER -
TY - CONF
TI - Approximate factorization of multivariate polynomials via differential equations
AU - Gao, Shuhong
AU - Kaltofen, Erich
AU - May, John
AU - Yang, Zhengfeng
AU - Zhi, Lihong
T2 - the 2004 international symposium
AB - The input to our algorithm is a multivariate polynomial, whose complex rational coefficients are considered imprecise with an unknown error that causes f to be irreducible over the complex numbers C. We seek to perturb the coefficients by a small quantitity such that the resulting polynomial factors over C. Ideally, one would like to minimize the perturbation in some selected distance measure, but no efficient algorithm for that is known. We give a numerical multivariate greatest common divisor algorithm and use it on a numerical variant of algorithms by W. M. Ruppert and S. Gao. Our numerical factorizer makes repeated use of singular value decompositions. We demonstrate on a significant body of experimental data that our algorithm is practical and can find factorizable polynomials within a distance that is about the same in relative magnitude as the input error, even when the relative error in the input is substantial (10-3).
C2 - 2004///
C3 - Proceedings of the 2004 international symposium on Symbolic and algebraic computation - ISSAC '04
DA - 2004///
DO - 10.1145/1005285.1005311
PB - ACM Press
SN - 158113827X
UR - http://dx.doi.org/10.1145/1005285.1005311
DB - Crossref
ER -
TY - JOUR
TI - Estimating variability in models for recurrent epidemics: assessing the use of moment closure techniques
AU - Lloyd, Alun L
T2 - Theoretical population biology
AB - The major role played by demographic stochasticity in determining the dynamics and persistence of childhood diseases, such as measles, chickenpox and pertussis, has long been realized. Techniques which can be used to estimate the magnitude of this stochastic effect are of clear importance. In this study, we assess and compare the use of two moment closure approximations to estimate the variability seen about the average behavior of stochastic models for the recurrent epidemics seen in childhood diseases. The performance of the approximations are assessed using analytic techniques available for the simplest epidemiological model and using numerical simulations in more complex settings. We also present epidemiologically important extensions of previous work, considering variability in the SEIR model and in situations for which there is seasonal variation in disease transmission. Important implications of stochastic effects for the dynamics of childhood diseases are highlighted, including serious deficiencies of deterministic descriptions of dynamical behavior.
DA - 2004///
PY - 2004///
DO - http://dx.doi.org/10.1016/j.tpb.2003.07.002
VL - 65
IS - 1
SP - 49-65
ER -
TY - JOUR
TI - Spatiotemporal dynamics of epidemics: synchrony in metapopulation models
AU - Lloyd, Alun L
AU - Jansen, Vincent AA
T2 - Mathematical biosciences
AB - Multi-patch models - also known as metapopulation models - provide a simple framework within which the role of spatial processes in disease transmission can be examined. An n-patch model which distinguishes between k different classes of individuals is considered. The linear stability of spatially homogeneous solutions of such models is studied using an extension of an analysis technique previously described for a population setting in which individuals migrate between patches according to a simple linear term. The technique considerably simplifies the analysis as it decouples the nk dimensional linearized system into n distinct k-dimensional systems. An important feature of the spatial epidemiological model is that the spatial coupling may involve non-linear terms. As an example of the use of this technique, the dynamical behavior in the vicinity of the endemic equilibrium of a symmetric SIR model is decomposed into spatial modes. For parameter values appropriate for childhood diseases, expressions for the eigenvalues corresponding to in-phase and out-of-phase modes are obtained, and it is shown that the dominant mode of the system is an in-phase mode. Furthermore, the out-of-phase modes are shown to decay much more rapidly than the in-phase mode for a broad range of coupling strengths.
DA - 2004///
PY - 2004///
DO - http://dx.doi.org/10.1016/j.mbs.2003.09.003
VL - 188
IS - 1-2
SP - 1-16
ER -
TY - JOUR
TI - Practical methods for optimal control using nonlinear programming, John T. Betts, SIAM, Philadelphia, PA, 2001, ISBN 0-89871-488-5
AU - Campbell, Stephen L.
T2 - International Journal of Robust and Nonlinear Control
AB - International Journal of Robust and Nonlinear ControlVolume 14, Issue 11 p. 1019-1021 Book ReviewFree Access Practical methods for optimal control using nonlinear programming, John T. Betts, SIAM, Philadelphia, PA, 2001, ISBN 0-89871-488-5 Stephen L. Campbell, Stephen L. Campbell slc@math.ncsu.edu Department of Mathematics, North Carolina State University, Raleigh, NC 27695-8205, U.S.A.Search for more papers by this author Stephen L. Campbell, Stephen L. Campbell slc@math.ncsu.edu Department of Mathematics, North Carolina State University, Raleigh, NC 27695-8205, U.S.A.Search for more papers by this author First published: 11 June 2004 https://doi.org/10.1002/rnc.874AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume14, Issue11Special Issue: Robust control design from data: direct and model-based approaches25 July 2004Pages 1019-1021 ReferencesRelatedInformation
DA - 2004/6/18/
PY - 2004/6/18/
DO - 10.1002/rnc.874
VL - 14
IS - 11
SP - 1019-1021
J2 - Int. J. Robust Nonlinear Control
LA - en
OP -
SN - 1049-8923 1099-1239
UR - http://dx.doi.org/10.1002/rnc.874
DB - Crossref
ER -
TY - JOUR
TI - Well-posedness for a nonsmooth acoustic system
AU - Banks, H.T
AU - Raye, J.K
T2 - Applied Mathematics Letters
AB - We consider an acoustic wave system with discontinuous coefficients and nonsmooth inputs. Existence, uniqueness, and continuous dependence on input data of weak solutions are established.
DA - 2004/3//
PY - 2004/3//
DO - 10.1016/S0893-9659(04)90069-9
VL - 17
IS - 3
SP - 317-322
J2 - Applied Mathematics Letters
LA - en
OP -
SN - 0893-9659
UR - http://dx.doi.org/10.1016/S0893-9659(04)90069-9
DB - Crossref
KW - well-posedness
KW - wave equations
KW - acoustics
ER -
TY - CONF
TI - Initialization of direct transcription optimal control software
AU - Betts, J.T.
AU - Campbell, S.L.
AU - Kalla, N.N.
T2 - 42nd IEEE International Conference on Decision and Control
AB - Direct transcription optimal control codes have been very successful. One common source of numerical difficulty is getting a feasible solution on the first iteration. Overcoming this often requires a high level of expertise on the user's part. This paper discusses research aimed at the development of a collection of utilities to assist users in solving complex industrial optimal control problems with direct transcription codes.
C2 - 2004/4/23/
C3 - 42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475)
DA - 2004/4/23/
DO - 10.1109/cdc.2003.1271741
PB - IEEE
SN - 0780379241
UR - http://dx.doi.org/10.1109/cdc.2003.1271741
DB - Crossref
ER -
TY - CONF
TI - A numerical integrator for simulation of unstructured implicit models
AU - Campbell, S.L.
AU - Selva, M.
AU - Arevalo, C.
T2 - Proceedings of the 2004 American Control Conference
AB - Object oriented modeling naturally leads to implicitly defined dynamical systems or, as they are also called, differential algebraic equations (DAEs). Most existing DAE integrators require the equations defining the dynamical system to have a special structure. Progress on the development of a new integrator for general unstructured DAEs is presented. The new integrator is called UCP. Computational tests are given to show that the new method can successfully integrate problems that other methods have trouble with.
C2 - 2004///
C3 - Proceedings of the 2004 American Control Conference
DA - 2004///
DO - 10.23919/acc.2004.1384754
PB - IEEE
SN - 0780383354
UR - http://dx.doi.org/10.23919/acc.2004.1384754
DB - Crossref
ER -
TY - CONF
TI - Software for auxiliary signal design
AU - Campbell, S.L.
AU - Nikoukhah, R.
T2 - Proceedings of the 2004 American Control Conference
AB - An approach for multi-model identification and failure detection in the presence of model uncertainty and bounded energy noise over finite time intervals has been introduced in the literature. This approach involved offline computation of an auxiliary signal and online application of a hyperplane test. This paper discusses progress in developing a software package to carry out this procedure.
C2 - 2004///
C3 - Proceedings of the 2004 American Control Conference
DA - 2004///
DO - 10.23919/acc.2004.1384004
PB - IEEE
SN - 0780383354
UR - http://dx.doi.org/10.23919/acc.2004.1384004
DB - Crossref
ER -
TY - JOUR
TI - The cd-index of Bruhat intervals
AU - Reading, N.
T2 - Electronic Journal of Combinatorics
DA - 2004///
PY - 2004///
VL - 11
IS - 1 R
SP - 1-25
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-8744221555&partnerID=MN8TOARS
ER -
TY - JOUR
TI - The cd-index of Bruhat intervals
AU - Reading, Nathan
T2 - The Electronic Journal of Combinatorics
AB - We study flag enumeration in intervals in the Bruhat order on a Coxeter group by means of a structural recursion on intervals in the Bruhat order. The recursion gives the isomorphism type of a Bruhat interval in terms of smaller intervals, using basic geometric operations which preserve PL sphericity and have a simple effect on the cd-index. This leads to a new proof that Bruhat intervals are PL spheres as well a recursive formula for the cd-index of a Bruhat interval. This recursive formula is used to prove that the cd-indices of Bruhat intervals span the space of cd-polynomials. The structural recursion leads to a conjecture that Bruhat spheres are "smaller" than polytopes. More precisely, we conjecture that if one fixes the lengths of $x$ and $y$, then the cd-index of a certain dual stacked polytope is a coefficientwise upper bound on the cd-indices of Bruhat intervals $[x,y]$. We show that this upper bound would be tight by constructing Bruhat intervals which are the face lattices of these dual stacked polytopes. As a weakening of a special case of the conjecture, we show that the flag h-vectors of lower Bruhat intervals are bounded above by the flag h-vectors of Boolean algebras (i. e. simplices).
DA - 2004///
PY - 2004///
DO - 10.37236/1827
VL - 11
IS - 1
SP - R74
UR - http://www.combinatorics.org/Volume_11/Abstracts/v11i1r74.html
ER -
TY - CONF
TI - Total variation information in image recovery
AU - Combettes, P.L.
AU - Pesquet, J.C.
T2 - International Conference on Image Processing
AB - Total variation has proven to be a valuable concept in connection with the recovery of images featuring piecewise smooth components. So far, however, it has been used exclusively as an objective to be minimized under a single constraint. In this paper, we propose an alternative framework in which total variation is used as a constraint in a general quadratic programming context. The advantage of this approach is that it allows for a wider range of constraints to be easily incorporated in the recovery process.
C2 - 2004/6/3/
C3 - Proceedings 2003 International Conference on Image Processing (Cat. No.03CH37429)
CY - Barcelona, Spain
DA - 2004/6/3/
PY - 2003/9/14/
DO - 10.1109/icip.2003.1247259
PB - IEEE
SN - 0780377508
UR - http://dx.doi.org/10.1109/icip.2003.1247259
ER -
TY - CONF
TI - Constraint construction in convex set theoretic signal recovery via Stein's principle [image denoising example]
AU - Combettes, P.L.
AU - Pesquet, J.-C.
T2 - 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing
AB - Convex set theoretic estimation methods have been shown to be effective in numerous signal recovery problems due to their ability to incorporate a wide range of deterministic and probabilistic information in the form of constraints on the solution. To date, probabilistic information has been used exclusively to constrain statistics of the estimation residual to be consistent with known properties of the noise. In this paper, we propose a new technique to construct constraint sets from probabilistic information based on Stein's identity. In this framework, probabilistic attributes of the signal to be recovered are estimated from the data. The proposed approach is applicable to signal formation models involving additive Gaussian noise and it leads to geometrically simple sets that can easily be handled via projection methods. An application to image denoising is demonstrated.
C2 - 2004/9/28/
C3 - 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing
CY - Montreal, Quebec, Canada
DA - 2004/9/28/
PY - 2004/5/17/
DO - 10.1109/icassp.2004.1326382
PB - IEEE
SN - 0780384849
UR - http://dx.doi.org/10.1109/icassp.2004.1326382
ER -
TY - JOUR
TI - Wavelet-constrained image restoration
AU - Combettes, Patrick L.
AU - Pesquet, Jean Christophe
T2 - International Journal of Wavelets, Multiresolution and Information Processing
AB - Image restoration problems can naturally be cast as constrained convex programming problems in which the constraints arise from a priori information and the observation of signals physically related to the image to be recovered. In this paper, the focus is placed on the construction of constraints based on wavelet representations. Using a mix of statistical and convex-analytical tools, we propose a general framework to construct wavelet-based constraints. The resulting optimization problem is then solved with a block-iterative parallel algorithm which offers great flexibility in terms of implementation. Numerical results illustrate an application of the proposed framework.
DA - 2004/12//
PY - 2004/12//
DO - 10.1142/s0219691304000688
VL - 2
IS - 4
SP - 371-389
SN - 0219-6913 1793-690X
UR - http://dx.doi.org/10.1142/s0219691304000688
ER -
TY - JOUR
TI - On wavelet-based numerical homogenization
AU - Chertock, Alina
AU - Levy, Doron
T2 - Multiscale Model. Simul.
AB - Recently, a wavelet-based method was introduced for the systematic derivation of subgrid scale models in the numerical solution of partial differential equations. Starting from a discretization of the multiscale differential operator, the discrete operator is represented in a wavelet space and projected onto a coarser subspace. The coarse (homogenized) operator is then replaced by a sparse approximation to increase the efficiency of the resulting algorithm. In this work we show how to improve the efficiency of this numerical homogenization method by choosing a different compact representation of the homogenized operator. In two dimensions our approach for obtaining a sparse representation is significantly simpler than the alternative sparse representations. $L^{\infty}$ error estimates are derived for a sample elliptic problem. An additional improvement we propose is a natural fine-scales correction that can be implemented in the final homogenization step. This modification of the scheme improves the resolution of the approximation without any significant increase in the computational cost. We apply our method to a variety of test problems including one- and two-dimensional elliptic models as well as wave propagation problems in materials with subgrid inhomogeneities.
DA - 2004///
PY - 2004///
DO - 10.1137/030600783
VL - 3
IS - 1
SP - 65-88
UR - https://doi-org.prox.lib.ncsu.edu/10.1137/030600783
KW - numerical homogenization
KW - wavelets
KW - Helmholtz equation
ER -
TY - JOUR
TI - On the application of lacunae-based methods to Maxwell's equations
AU - Tsynkov, S.V.
T2 - Journal of Computational Physics
AB - A straightforward application of the previously designed lacunae-based numerical methods to unsteady electro-magnetic problems would encounter certain difficulties, as it may violate the continuity of the charges and currents, which is a necessary solvability condition for the Maxwell equations. In the paper, we prove existence of the special auxiliary charges and currents that satisfy the continuity equations identically. We also show that using such charges and currents as a part of the numerical procedure provides a clear and unobstructed venue toward implementation of the lacunae-based methods in electromagnetics.
DA - 2004/9//
PY - 2004/9//
DO - 10.1016/j.jcp.2004.02.003
VL - 199
IS - 1
SP - 126-149
J2 - Journal of Computational Physics
LA - en
OP -
SN - 0021-9991
UR - http://dx.doi.org/10.1016/j.jcp.2004.02.003
DB - Crossref
KW - electromagnetic waves
KW - continuity equation
KW - solenoidal currents
KW - partition of unity
KW - unsteady propagation
KW - unbounded domains
KW - truncation
KW - finite computational domain
KW - sharp aft fronts
KW - Huygens' principle
KW - non-deteriorating method
KW - long-term numerical integration
ER -
TY - CONF
TI - Parallel Solution of the {Wigner-Poisson} Equations for {RTDs}
AU - Lasater, M S
AU - Kelley, C T
AU - Salinger, A
AU - Woolard, D L
AU - Zhao, P
A2 - Qingping, Quo
C2 - 2004///
C3 - 2004 International Symposium on Distributed Computing and Applications to Business, Engineering and Science
CY - Wuhan, China
DA - 2004///
SP - 672-676
PB - Hubei Science and Technology Press
ER -
TY - CONF
TI - Simulation of Nondifferentiable Models for Groundwater Flow and Transport
AU - Kelley, C T
AU - Fowler, K R
AU - Kees, C E
A2 - Miller, C T
A2 - Farthing, M. W.
A2 - Gray, W G
A2 - Pinter, G F
C2 - 2004///
C3 - Proceedings of Computational Methods in Water Resources XV
CY - Amsterdam
DA - 2004///
SP - 939-952
PB - Elsevier
ER -
TY - JOUR
TI - Implicit Filtering Revisited
AU - Conn, A R
AU - Kelley, C T
AU - Scheinberg, K
AU - Vicente, L N
DA - 2004///
PY - 2004///
ER -
TY - CONF
TI - Enhancement of Numerical Computations of the {W}igner-{P}oisson Equations for Application to the Simulation of {TH}z-Frequency {RTD} Oscillators
AU - Lasater, M S
AU - Kelley, C T
AU - Salinger, A
AU - Woolard, D L
AU - Zhao, P
T2 - North Carolina State University, Center for Research in Scientific Computation
A2 - Jensen, J O
A2 - Theriault, J-M
C2 - 2004///
C3 - Proceedings of SPIE: Chemical and Biological Standoff Detection II Volume 5584, paper number 07
DA - 2004///
SP - 42-51
ER -
TY - CONF
TI - A Hydraulic Capture Application for Optimal Remeidation Design
AU - Fowler, K R
AU - Kelley, C T
AU - Kees, C E
AU - Miller, C T
A2 - Miller, C T
A2 - Farthing, M. W.
A2 - Gray, W G
A2 - Pinter, G F
C2 - 2004///
C3 - Proceedings of Computational Methods in Water Resources XV
CY - Amsterdam
DA - 2004///
SP - 1149-1158
PB - Elsevier
ER -
TY - JOUR
TI - A Fast Algorithm for the {Ornstein-Zernike} Equations
AU - Kelley, C T
AU - Pettitt, B Montgomery
T2 - J. Comp. Phys.
DA - 2004///
PY - 2004///
VL - 197
SP - 491-591
ER -
TY - BOOK
TI - Characterization and Computation of a "Good Control"
AB - Models for physical systems often take the form of implicit or behavioral models. One important problem is the identification of which combinations of variables are good candidtates for control variables. This paper first provides one solution to this problem for linear time varying systems. The solution is shown to be related to a general optimization problem. It is then shown how these same algorithms can be extended to a large and important class of nonlinear systems.
DA - 2004/5/3/
PY - 2004/5/3/
DO - 10.18452/2583
ER -
TY - JOUR
TI - Finding best approximation pairs relative to two closed convex sets in Hilbert spaces
AU - Bauschke, Heinz H.
AU - Combettes, Patrick L.
AU - Luke, D.Russell
T2 - Journal of Approximation Theory
AB - We consider the problem of finding a best approximation pair, i.e., two points which achieve the minimum distance between two closed convex sets in a Hilbert space. When the sets intersect, the method under consideration, termed AAR for averaged alternating reflections, is a special instance of an algorithm due to Lions and Mercier for finding a zero of the sum of two maximal monotone operators. We investigate systematically the asymptotic behavior of AAR in the general case when the sets do not necessarily intersect and show that the method produces best approximation pairs provided they exist. Finitely many sets are handled in a product space, in which case the AAR method is shown to coincide with a special case of Spingarn's method of partial inverses.
DA - 2004/4//
PY - 2004/4//
DO - 10.1016/j.jat.2004.02.006
VL - 127
IS - 2
SP - 178-192
J2 - Journal of Approximation Theory
LA - en
OP -
SN - 0021-9045
UR - http://dx.doi.org/10.1016/j.jat.2004.02.006
DB - Crossref
KW - best approximation pair
KW - convex set
KW - firmly nonexpansive map
KW - Hilbert space
KW - hybrid projection-reflection method
KW - method of partial inverses
KW - normal cone
KW - projection
KW - reflection
KW - weak convergence
ER -
TY - JOUR
TI - Image Restoration Subject to a Total Variation Constraint
AU - Combettes, P.L.
AU - Pesquet, J.-C.
T2 - IEEE Transactions on Image Processing
AB - Total variation has proven to be a valuable concept in connection with the recovery of images featuring piecewise smooth components. So far, however, it has been used exclusively as an objective to be minimized under constraints. In this paper, we propose an alternative formulation in which total variation is used as a constraint in a general convex programming framework. This approach places no limitation on the incorporation of additional constraints in the restoration process and the resulting optimization problem can be solved efficiently via block-iterative methods. Image denoising and deconvolution applications are demonstrated.
DA - 2004/9//
PY - 2004/9//
DO - 10.1109/tip.2004.832922
VL - 13
IS - 9
SP - 1213-1222
J2 - IEEE Trans. on Image Process.
LA - en
OP -
SN - 1057-7149
UR - http://dx.doi.org/10.1109/tip.2004.832922
DB - Crossref
ER -
TY - JOUR
TI - Proximal Methods for Cohypomonotone Operators
AU - Combettes, Patrick L.
AU - Pennanen, Teemu
T2 - SIAM Journal on Control and Optimization
AB - Conditions are given for the viability and the weak convergence of an inexact, relaxed proximal point algorithm for finding a common zero of countably many cohypomonotone operators in a Hilbert space. In turn, new convergence results are obtained for an extended version of the proximal method of multipliers in nonlinear programming.
DA - 2004/1//
PY - 2004/1//
DO - 10.1137/s0363012903427336
VL - 43
IS - 2
SP - 731-742
J2 - SIAM J. Control Optim.
LA - en
OP -
SN - 0363-0129 1095-7138
UR - http://dx.doi.org/10.1137/s0363012903427336
DB - Crossref
KW - cohypomonotone operator
KW - common zero problem
KW - hypomonotone operator
KW - method of multipliers
KW - nonlinear programming
KW - proximal point method
KW - weak convergence
ER -
TY - JOUR
TI - Solving monotone inclusions via compositions of nonexpansive averaged operators
AU - Combettes, Patrick L.
T2 - Optimization
DA - 2004/10//
PY - 2004/10//
DO - 10.1080/02331930412331327157
VL - 53
IS - 5-6
SP - 475–504
SN - 0233-1934 1029-4945
UR - http://dx.doi.org/10.1080/02331930412331327157
KW - averaged operator
KW - Douglas-Rach ford method
KW - forward-backward method
KW - monotone inclusion
KW - monotone operator
KW - proximal point algorithm
ER -
TY - BOOK
TI - Applied Mathematical Models in Human Physiology
AU - Ottesen, Johnny T.
AU - Olufsen, Mette S.
AU - Larsen, Jesper K.
AB - Preface 1. Introduction 2. Cardiovascular and pulmonary physiology and anatomy 3. Blood flow in the heart 4. The ejection effect of the pumping heart 5. Modeling flow and pressure in the systemic arteries 6. A cardiovascular model 7. A baroreceptor model 8. Respiration Appendices Bibliography Index.
DA - 2004/1//
PY - 2004/1//
DO - 10.1137/1.9780898718287
OP -
PB - Society for Industrial and Applied Mathematics
SN - 9780898715392 9780898718287
UR - http://dx.doi.org/10.1137/1.9780898718287
DB - Crossref
ER -
TY - JOUR
TI - Modeling Cerebral Blood Flow Control During Posture Change from Sitting to Standing
AU - Olufsen, Mette
AU - Tran, Hien
AU - Ottesen, Johnny
T2 - Cardiovascular Engineering
AB - Hypertension, decreased cerebral blood flow, and diminished cerebral blood flow velocity regulation, are among the first signs indicating the presence of cerebral vascular disease. In this paper, we will present a mathematical model that can predict blood flow and pressure during posture change from sitting to standing. The mathematical model uses a compartmental approach to describe pulsatile blood flow velocity and pressure in a number of compartments representing the systemic circulation. Our model includes compartments representing the trunk and upper extremities, the lower extremities, the brain, and the heart. We use physiologically based control mechanisms to describe the regulation of cerebral blood flow velocity and arterial pressure in response to orthostatic hypotension resulting from postural change. To justify the fidelity of our mathematical model and control mechanisms development, we will show validation results of our model against experimental data from a young subject.
DA - 2004/3//
PY - 2004/3//
DO - 10.1023/b:care.0000025122.46013.1a
VL - 4
IS - 1
SP - 47-58
J2 - Cardiovascular Engineering
LA - en
OP -
SN - 1567-8822
UR - http://dx.doi.org/10.1023/b:care.0000025122.46013.1a
DB - Crossref
ER -
TY - JOUR
TI - Non-negative cd-coefficients of Gorenstein∗ posets
AU - Reading, Nathan
T2 - Discrete Mathematics
AB - We give a convolution formula for cd-index coefficients. The convolution formula, together with the proof by Davis and Okun of the Charney–Davis Conjecture in dimension 3, imply that certain cd-coefficients are non-negative for all Gorenstein ∗ posets. Additional coefficients are shown to be non-negative by interpreting them in terms of the top homology of certain Cohen–Macaulay complexes. In particular we verify, up to rank 6, Stanley's conjecture that the coefficients in the cd-index of a Gorenstein ∗ ranked poset are non-negative.
DA - 2004/1//
PY - 2004/1//
DO - 10.1016/j.disc.2003.07.001
VL - 274
IS - 1-3
SP - 323-329
J2 - Discrete Mathematics
LA - en
OP -
SN - 0012-365X
UR - http://dx.doi.org/10.1016/j.disc.2003.07.001
DB - Crossref
KW - cd-index
KW - Charney-Davis conjecture
KW - eulerian poset
KW - flag f-vector
KW - Gorenstein
ER -
TY - JOUR
TI - Lattice Congruences of the Weak Order
AU - Reading, Nathan
T2 - Order
AB - We study the congruence lattice of the poset of regions of a hyperplane arrangement, with particular emphasis on the weak order on a finite Coxeter group. Our starting point is a theorem from a previous paper which gives a geometric description of the poset of join-irreducibles of the congruence lattice of the poset of regions in terms of certain polyhedral decompositions of the hyperplanes. For a finite Coxeter system (W,S) and a subset $K\subseteq S$ , let ηK: w↦wK be the projection onto the parabolic subgroup WK. We show that the fibers of ηK constitute the smallest lattice congruence with 1≡s for every s∈(S−K). We give an algorithm for determining the congruence lattice of the weak order for any finite Coxeter group and for a finite Coxeter group of type A or B we define a directed graph on subsets or signed subsets such that the transitive closure of the directed graph is the poset of join-irreducibles of the congruence lattice of the weak order.
DA - 2004/11//
PY - 2004/11//
DO - 10.1007/s11083-005-4803-8
VL - 21
IS - 4
SP - 315-344
J2 - Order
LA - en
OP -
SN - 0167-8094 1572-9273
UR - http://dx.doi.org/10.1007/s11083-005-4803-8
DB - Crossref
KW - Cambrian lattice
KW - congruence uniform
KW - Coxeter group
KW - parabolic subgroup
KW - poset of regions
KW - shard
KW - simplicial hyperplane arrangement
KW - Tamari lattice
KW - weak order
ER -
TY - JOUR
TI - Connectivity of h-complexes
AU - Hersh, Patricia
T2 - Journal of Combinatorial Theory, Series A
AB - This paper verifies a conjecture of Edelman and Reiner regarding the homology of the h -complex of a Boolean algebra. A discrete Morse function with no low-dimensional critical cells is constructed, implying a lower bound on connectivity. This together with an Alexander duality result of Edelman and Reiner implies homology vanishing also in high dimensions. Finally, possible generalizations to certain classes of supersolvable lattices are suggested.
DA - 2004/1//
PY - 2004/1//
DO - 10.1016/j.jcta.2003.10.006
VL - 105
IS - 1
SP - 111-126
J2 - Journal of Combinatorial Theory, Series A
LA - en
OP -
SN - 0097-3165
UR - http://dx.doi.org/10.1016/j.jcta.2003.10.006
DB - Crossref
KW - discrete morse function
KW - h-vector
KW - Charney-Davis quantity
ER -
TY - JOUR
TI - A Hodge decomposition for the complex of injective words
AU - Hanlon, Phil
AU - Hersh, Patricia
T2 - Pacific Journal of Mathematics
AB - llReiner and Webb (preprint, 2002) compute the S n -module structure for the complex of injective words. This paper refines their formula by providing a Hodge type decomposition. Along the way, this paper proves that the simplicial boundary map interacts in a nice fashion with the Eulerian idempotents. The Laplacian acting on the top chain group in the complex of injective words is also shown to equal the signed random to random shuffle operator. Uyemura-Reyes, 2002, conjectured that the (unsigned) random to random shuffle operator has integral spectrum. We prove that this conjecture would imply that the Laplacian on (each chain group in) the complex of injective words has integral spectrum.
DA - 2004/3/1/
PY - 2004/3/1/
DO - 10.2140/pjm.2004.214.109
VL - 214
IS - 1
SP - 109-125
J2 - Pacific J. Math.
LA - en
OP -
SN - 0030-8730
UR - http://dx.doi.org/10.2140/pjm.2004.214.109
DB - Crossref
ER -
TY - JOUR
TI - Ideals of adjacent minors
AU - Hoşten, Serkan
AU - Sullivant, Seth
T2 - Journal of Algebra
AB - We give a description of the minimal primes of the ideal generated by the 2×2 adjacent minors of a generic matrix. We also compute the complete prime decomposition of the ideal of adjacent m×m minors of an m×n generic matrix when the characteristic of the ground field is zero. A key intermediate result is the proof that the ideals which appear as minimal primes are, in fact, prime ideals. This introduces a large new class of mixed determinantal ideals that are prime.
DA - 2004/7//
PY - 2004/7//
DO - 10.1016/j.jalgebra.2004.01.027
VL - 277
IS - 2
SP - 615-642
J2 - Journal of Algebra
LA - en
OP -
SN - 0021-8693
UR - http://dx.doi.org/10.1016/j.jalgebra.2004.01.027
DB - Crossref
ER -
TY - JOUR
TI - A Divide-and-Conquer Algorithm for Generating Markov Bases of Multi-way Tables
AU - Dobra, Adrian
AU - Sullivant, Seth
T2 - Computational Statistics
DA - 2004/9//
PY - 2004/9//
DO - 10.1007/bf03372101
VL - 19
IS - 3
SP - 347-366
J2 - CompStat
LA - en
OP -
SN - 0943-4062 1613-9658
UR - http://dx.doi.org/10.1007/bf03372101
DB - Crossref
KW - contingency tables
KW - decomposable graphical models
KW - disclosure limitation
KW - exact distributions
KW - Grobner bases
KW - Markov bases
ER -
TY - CONF
TI - The North Carolina State University women in science and engineering program: a community for living and learning
AU - Rajala, S. A.
AU - Bottomley, L.J.
AU - Parry, E. A.
AU - Cohen, J. D.
AU - Grant, S. C.
AU - Thomas, C. J.
AU - Doxey, T. M.
AU - Perez, G.
AU - Collins, R. E.
AU - Spurlin, J. E.
C2 - 2004///
C3 - American Society for Engineering Education
DA - 2004///
ER -
TY - JOUR
TI - Oversampling, quasi-affine frames, and wave packets
AU - Hernandez, E.
AU - Labate, D.
AU - Weiss, G.
AU - al.,
T2 - Applied and Computational Harmonic Analysis
AB - In [E. Hernández, D. Labate, G. Weiss, J. Geom. Anal. 12 (4) (2002) 615–662], three of the authors obtained a characterization of certain types of reproducing systems. In this work, we apply these results and methods to various affine-like, wave packets and Gabor systems to determine their frame properties. In particular, we study how oversampled systems inherit properties (like the frame bounds) of the original systems. Moreover, our approach allows us to study the phenomenon of oversampling in much greater generality than is found in the literature.
DA - 2004///
PY - 2004///
DO - 10.1016/j.acha.2003.12.002
VL - 16
IS - 2
SP - 111-147
ER -
TY - JOUR
TI - Polymorphism in the interleukin-10 promoter affects both provirus load and the risk of human T lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis
AU - Sabouri, AH
AU - Saito, M
AU - Lloyd, AL
AU - Vine, AM
AU - Witkover, AW
AU - Furukawa, Y
AU - Izumo, S
AU - Arimura, K
AU - Marshall, SEF
AU - Usuku, K
AU - Bangham, CRM
AU - Osame, M
T2 - JOURNAL OF INFECTIOUS DISEASES
AB - To investigate non-human leukocyte antigen candidate genes that influence the outcome of human T cell lymphotropic virus (HTLV) type I infection, we analyzed 6 single-nucleotide polymorphisms in the interleukin (IL)-10 promoter region in 280 patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and 255 HTLV-I-seropositive asymptomatic carriers from an area where HTLV-I is endemic. The IL-10 -592 A allele, which shows lower HTLV-I Tax-induced transcriptional activity than the C allele in the Jurkat T cell line, was associated with a >2-fold reduction in the odds of developing HAM/TSP (P=.011; odds ratio [OR], 0.50 [95% confidence interval, 0.30-0.86]) by reducing the provirus load in the whole cohort (P=.009, analysis of variance). Given the OR and the observed frequency of IL-10 -592 A, we demonstrate that this allele prevents approximately 44.7% (standard deviation, +/-13.1%) of potential cases of HAM/TSP, which indicates that it defines one component of the genetic susceptibility to HAM/TSP in the cohort.
DA - 2004/10/1/
PY - 2004/10/1/
DO - 10.1086/423942
VL - 190
IS - 7
SP - 1279-1285
SN - 1537-6613
ER -
TY - JOUR
TI - Variance reduction for Monte Carlo methods to evaluate option prices under multi-factor stochastic volatility models
AU - Fouque, JP
AU - Han, CH
T2 - QUANTITATIVE FINANCE
AB - We present variance reduction methods for Monte Carlo simulations to evaluate European and Asian options in the context of multiscale stochastic volatility models. European option price approximations, obtained from singular and regular perturbation analysis [Fouque J P, Papanicolaou G, Sircar R and Solna K 2003 Multiscale stochastic volatility asymptotics, SIAM J. Multiscale Modeling and Simulation 2], are used in importance sampling techniques, and their efficiencies are compared. Then we investigate the problem of pricing arithmetic average Asian options (AAOs) by Monte Carlo simulations. A two-step strategy is proposed to reduce the variance where geometric average Asian options (GAOs) are used as control variates. Due to the lack of analytical formulas for GAOs under stochastic volatility models, it is then necessary to consider efficient Monte Carlo methods to estimate the unbiased means of GAOs. The second step consists in deriving formulas for approximate prices based on perturbation techniques, a...
DA - 2004/10//
PY - 2004/10//
DO - 10.1080/14697680400020317
VL - 4
IS - 5
SP - 597-606
SN - 1469-7696
ER -
TY - JOUR
TI - Modeling and optimal regulation of erythropoiesis subject to benzene intoxication
AU - Banks, HT
AU - Cole, CE
AU - Schlosser, PM
AU - Tran, HT
T2 - MATHEMATICAL BIOSCIENCES AND ENGINEERING
AB - Benzene (C6H6) is a highly flammable, colorless liquid. Ubiquitous exposures result from its presence in gasoline vapors, cigarette smoke, andindustrial processes. Benzene increases the incidence of leukemia in humanswhen they are exposed to high doses for extended periods; however, leukemiarisks in humans subjected to low exposures are uncertain. The exposure-dose-response relationship of benzene in humans is expected to be nonlinear becausebenzene undergoes a series of metabolic transformations, detoxifying and activating, resulting in various metabolites that exert toxic e ffects on the bonemarrow. Since benzene is a known human leukemogen, the toxicity of benzene in thebone marrow is of most importance. And because blood cells are producedin the bone marrow, we investigated the eff ects of benzene on hematopoiesis(blood cell production and development). An age-structured model was usedto examine the process of erythropoiesis, the development of red blood cells.This investigation proved the existence and uniqueness of the solution of thesystem of coupled partial and ordinary di fferential equations. In addition, weformulated an optimal control problem for the control of erythropoiesis andperformed numerical simulations to compare the performance of the optimalfeedback law and another feedback function based on the Hill function.
DA - 2004/6//
PY - 2004/6//
DO - 10.3934/mbe.2004.1.15
VL - 1
IS - 1
SP - 15-48
SN - 1547-1063
KW - hematopoiesis
KW - age-structured model
KW - existence and uniqueness
KW - optimal control
ER -
TY - JOUR
TI - Dynamic multidrug therapies for HIV: Optimal and STI control approaches
AU - Adams, B. M.
AU - Banks, H. T.
AU - Kwon, H. D.
AU - Tran, Hien
T2 - Mathematical Biosciences and Engineering
AB - We formulate a dynamic mathematical model that describes the interaction of the immune system with the human immunodeficiency virus (HIV) and that permits drug ''cocktail'' therapies. We derive HIV therapeutic strategies by formulating and analyzing an optimal control problem using two types of dynamic treatments representing reverse transcriptase (RT) inhibitors and protease inhibitors (PIs). Continuous optimal therapies are found by solving the corresponding optimality systems. In addition, using ideas from dynamic programming, we formulate and derive suboptimal structured treatment interruptions (STI) in antiviral therapy that include drug-free periods of immune-mediated control of HIV. Our numerical results support a scenario in which STI therapies can lead to long-term control of HIV by the immune response system after discontinuation of therapy.
DA - 2004///
PY - 2004///
DO - 10.3934/mbe.2004.1.223
VL - 1
IS - 2
SP - 223–241
ER -
TY - JOUR
TI - Gradient driven and singular flux blowup of smooth solutions to hyperbolic systems of conservation laws
AU - Jenssen, HK
AU - Young, R
T2 - JOURNAL OF HYPERBOLIC DIFFERENTIAL EQUATIONS
AB - We consider two new classes of examples of sup-norm blowup in finite time for strictly hyperbolic systems of conservation laws. The explosive growth in amplitude is caused either by a gradient catastrophe or by a singularity in the flux function. The examples show that solutions of uniformly strictly hyperbolic systems can remain as smooth as the initial data until the time of blowup. Consequently, blowup in amplitude is not necessarily strictly preceded by shock formation.
DA - 2004/12//
PY - 2004/12//
DO - 10.1142/S021989160400024X
VL - 1
IS - 4
SP - 627-641
SN - 1793-6993
KW - blowup
KW - smoothness
KW - systems of hyperbolic conservation laws
ER -
TY - JOUR
TI - Comparison of two dynamic contact line models for driven thin liquid films
AU - Levy, R
AU - Shearer, M
T2 - EUROPEAN JOURNAL OF APPLIED MATHEMATICS
AB - The modeling of the motion of a contact line, the triple point at which solid, liquid and air meet, is a major outstanding problem in the fluid mechanics of thin films [2, 9]. In this paper, we compare two well-known models in the specific context of Marangoni driven films. The precursor model replaces the contact line by a sharp transition between the bulk fluid and a thin layer of fluid, effectively pre-wetting the solid; the Navier slip model replaces the usual no-slip boundary condition by a singular slip condition that is effective only very near the contact line. We restrict attention to traveling wave solutions of the thin film PDE for a film driven up an inclined planar solid surface by a thermally induced surface tension gradient. This involves analyzing third order ODE that depend on several parameters. The two models considered here have subtle differences in their description, requiring a careful treatment when comparing traveling waves and effective contact angles. Numerical results exhibit broad agreement between the two models, but the closest comparison can be done only for a rather restricted range of parameters. The driven film context gives contact angle results quite different from the case of a film moving under the action of gravity alone. The numerical technique for exploring phase portraits for the third order ODE is also used to tabulate the kinetic relation and nucleation condition, information that can be used with the underlying hyperbolic conservation law to explain the rich combination of wave structures observed in simulations of the PDE and in experiments [3, 15].
DA - 2004/12//
PY - 2004/12//
DO - 10.1017/S0956792504005741
VL - 15
SP - 625-642
SN - 1469-4425
ER -
TY - JOUR
TI - Control of mobile communication systems with time-varying channels via stability methods
AU - Buche, R
AU - Kushner, HJ
T2 - IEEE TRANSACTIONS ON AUTOMATIC CONTROL
AB - Consider the forward link of a mobile communications system with a single transmitter and connecting to K destinations via randomly varying channels. Data arrives in some random way and is queued according to the K destinations until transmitted. Time is divided into small scheduling intervals. Current systems can estimate the channel (e.g, via pilot signals) and use this information for scheduling. The issues are the allocation of transmitter power and/or time and bandwidth to the various queues in a queue and channel-state dependent way to assure stability and good operation. The decisions are made at the beginning of the scheduling intervals. Stochastic stability methods are used both to assure that the system is stable and to get appropriate allocations, under very weak conditions. The choice of Lyapunov function allows a choice of the effective performance criteria. The resulting controls are readily implementable and allow a range of tradeoffs between current rates and queue lengths. The various extensions allow a large variety of schemes of current interest to be covered. All essential factors are incorporated into a "mean rate" function, so that the results cover many different systems. Because of the non-Markovian nature of the problem, we use the perturbed Stochastic Lyapunov function method, which is well adapted to such problems. The method is simple and effective.
DA - 2004/11//
PY - 2004/11//
DO - 10.1109/TAC.2004.837590
VL - 49
IS - 11
SP - 1954-1962
SN - 0018-9286
KW - mobile communications
KW - perturbed Lyapunov function
KW - stability
KW - time-varying systems
ER -
TY - JOUR
TI - Non-classical Riemann solvers with nucleation
AU - LeFloch, PG
AU - Shearer, M
T2 - PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
AB - We introduce a new non-classical Riemann solver for scalar conservation laws with concave–convex flux-function. This solver is based on both a kinetic relation, which determines the propagation speed of (under-compressive) non-classical shock waves, and a nucleation criterion, which makes a choice between a classical Riemann solution and a non-classical one. We establish the existence of (non-classical entropy) solutions of the Cauchy problem and discuss several examples of wave interactions. We also show the existence of a class of solutions, called splitting–merging solutions, which are made of two large shocks and small bounded-variation perturbations. The nucleation solvers, as we call them, are applied to (and actually motivated by) the theory of thin-film flows; they help explain numerical results observed for such flows.
DA - 2004///
PY - 2004///
DO - 10.1017/s0308210500003577
VL - 134
IS - 2004
SP - 961-984
SN - 1473-7124
ER -
TY - BOOK
TI - Computational mathematics: Models, methods, and analysis with MATLAB and MPI
AU - White, R. E.
CN - QA297 .W495 2004
DA - 2004///
PY - 2004///
PB - Boca Raton, Fla.: Chapman & Hall/CRC
SN - 1584883642
ER -
TY - JOUR
TI - Wavelets with composite dilations
AU - Guo, KH
AU - Labate, D
AU - Lim, WQ
AU - Weiss, G
AU - Wilson, E
T2 - ELECTRONIC RESEARCH ANNOUNCEMENTS OF THE AMERICAN MATHEMATICAL SOCIETY
AB - A wavelet with composite dilations is a function generating an orthonormal basis or a Parseval frame for L 2 ( R n ) L^2({\mathbb R}^n) under the action of lattice translations and dilations by products of elements drawn from non-commuting matrix sets A A and B B . Typically, the members of B B are shear matrices (all eigenvalues are one), while the members of A A are matrices expanding or contracting on a proper subspace of R n {\mathbb R}^n . These wavelets are of interest in applications because of their tendency to produce “long, narrow” window functions well suited to edge detection. In this paper, we discuss the remarkable extent to which the theory of wavelets with composite dilations parallels the theory of classical wavelets, and present several examples of such systems.
DA - 2004///
PY - 2004///
DO - 10.1090/S1079-6762-04-00132-5
VL - 10
SP - 78-87
SN - 1079-6762
KW - affine systems
KW - frames
KW - multiresolution analysis (MRA)
KW - multiwavelets
KW - wavelets
ER -
TY - JOUR
TI - Radiographic and clinical changes of the tibial tuberosity after tibial plateau leveling osteotomy
AU - Kergosien, DH
AU - Barnhart, MD
AU - Kees, CE
AU - Danielson, BG
AU - Brourman, JD
AU - Dehoff, WD
AU - Schertel, ER
T2 - VETERINARY SURGERY
AB - Objective— To investigate radiographic changes of the tibial tuberosity after tibial plateau leveling osteotomy (TPLO) surgery and identify clinical findings and risk factors associated with such changes. Study Design— Retrospective study. Sample Population— Hundred and eighty-six client-owned dogs (219 stifles) that had TPLO surgery. Methods— Patient data retrieved included radiographic changes of the tibial tuberosity during re-examination, age, body weight, whether unilateral or single-session bilateral surgery had been performed, location of the anti-rotational pin, approximate tibial tuberosity area, and approximate average tibial tuberosity width. Results— Fracture with resulting caudal displacement of the proximal tibial tuberosity (1.4%; 3 of 219) occurred less frequently than non-displaced tibial tuberosity fractures (7.3%; 16 of 219). Age, weight, average tibial tuberosity width, location of the anti-rotational pin, and single session bilateral surgery were identified as risks factors for non-displaced fracture. Weight divided by the square of the average tibial tuberosity width may be a stronger risk factor than either weight or average tibial tuberosity width alone. Conclusions— Dogs undergoing single session bilateral TPLO surgery are at greater risk for developing non-displaced tibial tuberosity fractures. The non-displaced tibial tuberosity fracture does not appear to adversely affect outcome or lead to tibial tuberosity avulsion. Significant risk factors for fracture of the proximal tibial tuberosity with caudal displacement were not identified. Clinical Relevance— Factors including age, weight, tibial tuberosity thickness, and conditions that may enhance strain on the tibial tuberosity, such as single-session bilateral procedures, may increase risk of fracture.
DA - 2004///
PY - 2004///
DO - 10.1111/j.1532-950X.2004.04066.x
VL - 33
IS - 5
SP - 468-474
SN - 0161-3499
KW - tibial plateau leveling osteotomy
KW - tibial tuberosity
KW - radiographic change
KW - cranial cruciate ligament
KW - dog
ER -
TY - JOUR
TI - On the semigroup of standard symplectic matrices and its applications
AU - Chu, M
AU - Del Buono, N
AU - Diele, F
AU - Politi, T
AU - Ragni, S
T2 - LINEAR ALGEBRA AND ITS APPLICATIONS
AB - A matrix Z∈R2n×2n is said to be in the standard symplectic form if Z enjoys a block LU-decomposition in the sense of A0−HIZ=IG0AT, where A is nonsingular and both G and H are symmetric and positive definite in Rn×n. Such a structure arises naturally in the discrete algebraic Riccati equations. This note contains two results: First, by means of a parameter representation it is shown that the set of all 2n×2n standard symplectic matrices is closed under multiplication and, thus, forms a semigroup. Secondly, block LU-decompositions of powers of Z can be derived in closed form which, in turn, can be employed recursively to induce an effective structure-preserving algorithm for solving the Riccati equations. The computational cost of doubling and tripling of the powers is investigated. It is concluded that doubling is the better strategy.
DA - 2004/9/15/
PY - 2004/9/15/
DO - 10.1016/j.laa.2004.03.017
VL - 389
IS - 1-3
SP - 215-225
SN - 1873-1856
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3943079249&partnerID=MN8TOARS
KW - standard symplectic form
KW - discrete algebraic Riccati equation
KW - structure preserving
KW - power method
KW - block LU decomposition
KW - semigroup
ER -
TY - JOUR
TI - On the application of lacunae-based methods to Maxwell's equations
AU - Tsynkov, Semyon
T2 - Journal of Computational Physics
DA - 2004///
PY - 2004///
DO - 10.1016/.jcp.2004.02.003
VL - 199
IS - 1
SP - 126–149
ER -
TY - JOUR
TI - Approximate solution of singular integro-differential equations by reduction over Faber-Laurent polynomials
AU - Zolotarevskii, VA
AU - Li, ZL
AU - Caraus, I
T2 - DIFFERENTIAL EQUATIONS
DA - 2004/12//
PY - 2004/12//
DO - 10.1007/s10625-005-0108-3
VL - 40
IS - 12
SP - 1764-1769
SN - 0012-2661
ER -
TY - JOUR
TI - Probabilities of extinction, weak extinction, permanence, and mutual exclusion in discrete, competitive, Lotka-Volterra systems that involve invading species
AU - Chan, DM
AU - Franke, JE
T2 - MATHEMATICAL AND COMPUTER MODELLING
AB - The probabilities of various biological asymptotic dynamics are computed for a stable system that is invaded by another competing species. The asymptotic behaviors studied include extinction, weak extinction, permanence, and mutual exclusion. The model used is a discrete Lotka-Volterra system that models species that compete for the same resources. Among the results found are that the chance of permanence occurring in the invaded system is significantly higher than the probability of permanence in a purely random system, and that multiple extinctions that include the invading species and one of the original species are impossible.
DA - 2004/10//
PY - 2004/10//
DO - 10.1016/j.mcm.2004.10.013
VL - 40
IS - 7-8
SP - 809-821
SN - 1872-9479
KW - extinction
KW - permanence
KW - mutual exclusion
KW - competition
KW - Lotka-Volterra
KW - weak extinction
KW - invader
KW - strongly permanent
ER -
TY - JOUR
TI - Path collapse for multidimensional Brownian motion with rebirth
AU - Grigorescu, I
AU - Kang, M
T2 - STATISTICS & PROBABILITY LETTERS
AB - In a bounded open region of the d-dimensional Euclidean space we consider a Brownian motion which is reborn at a fixed interior point as soon as it reaches the boundary. It was shown that in dimension one coupled paths starting at different points but driven by the same Brownian motion either collapse with probability one or never meet. In higher dimensions, for convex or polyhedral regions, the paths with positive probability of collapse differ at start by a vector from a set of codimension one. The problem can be interpreted in terms of the long term mixing properties of the payoff of a portfolio of knock-out barrier options in derivatives markets.
DA - 2004/12/1/
PY - 2004/12/1/
DO - 10.1016/j.spl.2004.10.006
VL - 70
IS - 3
SP - 199-209
SN - 1879-2103
KW - absorbing Brownian motion
KW - harmonic measure
KW - collapsing paths
KW - barrier options
ER -
TY - JOUR
TI - LBIC imaging of semiconductor arrays: The cross-sectional model
AU - Fang, WF
AU - Ito, K
AU - Redfern, DA
T2 - MATHEMATICAL AND COMPUTER MODELLING
AB - Laser beam induced current (LBIC)/nondestructive technique that has been used for a number of years to qualitatively examine large arrays of p-n junctions, especially in HgCdTe infrared focal plane arrays. In this paper, we quantitatively study the application of the LBIC imaging technique to semiconductor arrays Based on a previous mathematical model for LBIC applied to individual devices, we employ the homogenization method to derive approximations of the LBIC images of large arrays. Such approximations reduce the computational burden in simulations of these LBIC bouges. We then illustrate the application of our approximations for the purpose of recovering array parameters from the LBIC images.
DA - 2004/7//
PY - 2004/7//
DO - 10.1016/j.mcm.2003.10.045
VL - 40
IS - 1-2
SP - 127-136
SN - 1872-9479
KW - homogenization
KW - LBIC
KW - semiconductor arrays
KW - inverse problem
KW - parameter identification
ER -
TY - JOUR
TI - Kronecker product approximate preconditioner for SANs
AU - Langville, AN
AU - Stewart, WJ
T2 - NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS
AB - Many very large Markov chains can be modelled efficiently as stochastic automata networks (SANs). A SAN is composed of individual automata which, for the most part, act independently, requiring only infrequent interaction. SANs represent the generator matrix Q of the underlying Markov chain compactly as the sum of Kronecker products of smaller matrices. Thus, storage savings are immediate. The benefit of a SAN's compact representation, known as the descriptor, is often outweighed by its tendency to make analysis of the underlying Markov chain tough. While iterative or projections methods have been used to solve the system πQ=0, the time until these methods converge to the stationary solution π is still unsatisfactory. SAN's compact representation has made the next logical research step of preconditioning thorny. Several preconditioners for SANs have been proposed and tested, yet each has enjoyed little or no success. Encouraged by the recent success of approximate inverses as preconditioners, we have explored their potential as SAN preconditioners. One particularly relevant finding on approximate inverse preconditioning is the nearest Kronecker product approximation discovered by Pitsianis and Van Loan. In this paper, we extend the nearest Kronecker product technique to approximate the Q matrix for an SAN with a Kronecker product, A1 ⊗ A2 ⊗…⊗ AN. Then, we take M = A 1 −1 ⊗ A 2 −1 ⊗…⊗ A N −1 as our SAN NKP preconditioner. Copyright © 2004 John Wiley & Sons, Ltd.
DA - 2004///
PY - 2004///
DO - 10.1002/nla.344
VL - 11
IS - 8-9
SP - 723-752
SN - 1099-1506
KW - stochastic automata networks
KW - nearest Kronecker products
KW - inultilinear alaebra
KW - preconditioning
ER -
TY - JOUR
TI - Existence of Dafermos profiles for singular shocks
AU - Schecter, S.
T2 - Journal of Differential Equations
DA - 2004///
PY - 2004///
DO - 10.1016/j.ide.2004.06.013
VL - 205
IS - 1
SP - 185-210
ER -
TY - JOUR
TI - Time-reversal simulations for detection in randomly layered media
AU - Haider, MA
AU - Mehta, KJ
AU - Fouque, JP
T2 - WAVES IN RANDOM MEDIA
AB - Abstract A time-reversal mirror is, roughly speaking, a device which is capable of receiving an acoustic signal in time, keeping it in memory and sending it back into the medium in the reversed direction of time. In this paper, we employ an accurate numerical method for simulating waves propagating in complex one-dimensional media. We use numerical simulations to reproduce the time-reversal self-averaging effect which takes place in randomly layered media. This is done in the regime where the inhomogeneities are smaller than the pulse, which propagates over long distances compared to its width. We show numerical evidence for possible use of an expanding window time-reversal technique for detecting anomalies buried in the medium.
DA - 2004/4//
PY - 2004/4//
DO - 10.1088/0959-7174/14/2/007
VL - 14
IS - 2
SP - 185-198
SN - 0959-7174
ER -
TY - JOUR
TI - The McCormack model: channel flow of a binary gas mixture driven by temperature, pressure and density gradients
AU - Siewert, CE
AU - Valougeorgis, D
T2 - EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
AB - An analytical version of the discrete-ordinates method (the ADO method) is used to establish concise and particularly accurate solutions to the problems of Poiseuille flow, thermal-creep flow and diffusion flow for a binary gas mixture confined between parallel walls. The kinetic equations used to describe the flow are based on the McCormack model for mixtures. The analysis yields, for the general (specular-diffuse) case of Maxwell boundary conditions for each of the two species, the velocity, heat-flow and shear-stress profiles for both types of particles. Numerical results are reported for two binary mixtures (Ne–Ar and He–Xe) with various molar concentrations. The complete solution requires only a (matrix) eigenvalue/eigenvector routine and a solver of a system of linear algebraic equations, and thus the algorithm is considered especially easy to use. The developed (FORTRAN) code requires typically less than a second on a 2.2 GHz Pentium IV machine to solve all three problems.
DA - 2004///
PY - 2004///
DO - 10.1016/j.euromechflu.2004.03.003
VL - 23
IS - 4
SP - 645-664
SN - 1873-7390
ER -
TY - JOUR
TI - Stochastic volatility corrections for interest rate derivatives
AU - Cotton, P.
AU - Fouque, J. P.
AU - Papanicolaou, G.
AU - Sircar, R.
T2 - Mathematical Finance: An International Journal of Mathematics, Statistics, and Financial Theory
DA - 2004///
PY - 2004///
VL - 14
IS - 2
SP - 173-200
ER -
TY - JOUR
TI - Special issue devoted to papers presented at the Conference on the Numerical Solution of Markov Chains 2003 - Preface
AU - Langville, AN
AU - Stewart, WJ
T2 - LINEAR ALGEBRA AND ITS APPLICATIONS
DA - 2004/7/15/
PY - 2004/7/15/
DO - 10.1016/j.laa.2004.02.016
VL - 386
SP - 1-2
SN - 1873-1856
ER -
TY - JOUR
TI - Solution of a well-field design problem with implicit filtering
AU - Fowler, KR
AU - Kelley, CT
AU - Miller, CT
AU - Kees, CE
AU - Darwin, RW
AU - Reese, JP
AU - Farthing, MW
AU - Reed, MSC
T2 - OPTIMIZATION AND ENGINEERING
AB - Problems involving the management of groundwater resources occur routinely, and management decisions based upon optimization approaches offer the potential to save substantial amounts of money. However, this class of application is notoriously difficult to solve due to non-convex objective functions with multiple local minima and both nonlinear models and nonlinear constraints. We solve a subset of community test problems from this ap- plication field using MODFLOW, a standard groundwater flow model, and IFFCO, an implicit filtering algorithm that was designed to solve problems similar to those of focus in this work. While sampling methods have received only scant attention in the groundwater optimization literature, we show encouraging results that suggest they are deserving of more widespread consideration for this class of problems. In keeping with our objectives for the community problems, we have packaged the approaches used in this work to facilitate additional work on these problems by others and the application of implicit filtering to other problems in this field. We provide the data for our formulation and solution on the web.
DA - 2004/6//
PY - 2004/6//
DO - 10.1023/B:OPTE.0000033375.33183.e7
VL - 5
IS - 2
SP - 207-234
SN - 1573-2924
KW - implicit filtering
KW - well field design
KW - groundwater flow and transport
ER -
TY - JOUR
TI - Maturity cycles in implied volatility
AU - Fouque, JP
AU - Papanicolaou, G
AU - Sircar, R
AU - Solna, K
T2 - FINANCE AND STOCHASTICS
AB - The skew effect in market implied volatility can be reproduced by option pricing theory based on stochastic volatility models for the price of the underlying asset. Here we study the performance of the calibration of the S&P 500 implied volatility surface using the asymptotic pricing theory under fast mean-reverting stochastic volatility described in [8]. The time-variation of the fitted skew-slope parameter shows a periodic behaviour that depends on the option maturity dates in the future, which are known in advance. By extending the mathematical analysis to incorporate model parameters which are time-varying, we show this behaviour can be explained in a manner consistent with a large model class for the underlying price dynamics with time-periodic volatility coefficients.
DA - 2004/11//
PY - 2004/11//
DO - 10.1007/s00780-004-0126-7
VL - 8
IS - 4
SP - 451-477
SN - 1432-1122
KW - implied volatilities
KW - maturity cycles
KW - fast mean-reverting stochastic volatility
KW - asymptotic expansions
ER -
TY - JOUR
TI - L-infinity structures on spaces with three one-dimensional components
AU - Daily, M
T2 - COMMUNICATIONS IN ALGEBRA
AB - Abstract L ∞ structures have been a subject of recent interest in physics, where they occur in closed string theory and in gauge theory. This paper provides a class of easily constructible examples of L n and L ∞ structures on graded vector spaces with three one-dimensional components. In particular, it demonstrates a way to classify all possible L n and L ∞ structures on V = V m ⊕ V m+1 ⊕ V m+2 when each of the three components is one-dimensional. Included are necessary and sufficient conditions under which a space with an L 3 structure is a differential graded Lie algebra. It is also shown that some of these differential graded Lie algebras possess a nontrivial L n structure for higher n.
DA - 2004///
PY - 2004///
DO - 10.1081/AGB-120029922
VL - 32
IS - 5
SP - 2041-2059
SN - 0092-7872
KW - L-intinity algebras
KW - strongly homotopy Lie algebras
ER -
TY - JOUR
TI - Injective properties of complex matrices
AU - Meyer, C.
T2 - American Mathematical Monthly
DA - 2004///
PY - 2004///
DO - 10.2307/4145059
VL - 111
IS - 8
SP - 728
ER -
TY - JOUR
TI - Deterministic distinct-degree factorization of polynomials over finite fields
AU - Gao, SH
AU - Kaltofen, E
AU - Lauder, AGB
T2 - JOURNAL OF SYMBOLIC COMPUTATION
AB - A deterministic polynomial time algorithm is presented for finding the distinct-degree factorization of multivariate polynomials over finite fields. As a consequence, one can count the number of irreducible factors of polynomials over finite fields in deterministic polynomial time, thus resolving a theoretical open problem of Kaltofen from 1987.
DA - 2004/12//
PY - 2004/12//
DO - 10.1016/j.jsc.2004.05.004
VL - 38
IS - 6
SP - 1461-1470
SN - 0747-7171
KW - multivariate polynomial
KW - deterministic algorithm
KW - distinct-degree factorization
ER -
TY - JOUR
TI - Determinantal identities over commutative semirings
AU - Poplin, PL
AU - Hartwig, RE
T2 - LINEAR ALGEBRA AND ITS APPLICATIONS
AB - We present a development of determinantal identities over commutative semirings. This includes a generalization of the Cauchy–Binet and Laplace Theorems, as well as results on compound matrices and adjoints. It is further shown that Laplace's Theorem is a special case of the grade- s -adjoint identity.
DA - 2004/8/1/
PY - 2004/8/1/
DO - 10.1016/j.laa.2004.02.019
VL - 387
SP - 99-132
SN - 0024-3795
KW - semiring
KW - determinant
KW - laplace
KW - Cauchy-Binet
ER -
TY - JOUR
TI - Variability of the recent climate of eastern Africa
AU - Schreck, CJ
AU - Semazzi, FHM
T2 - INTERNATIONAL JOURNAL OF CLIMATOLOGY
AB - The primary objective of this study is to investigate the recent variability of the eastern African climate. The region of interest is also known as the Greater Horn of Africa (GHA), and comprises the countries of Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Somalia, Sudan, Uganda, and Tanzania. The analysis was based primarily on the construction of empirical orthogonal functions (EOFs) of gauge rainfall data and on CPC Merged Analysis of Precipitation (CMAP) data, derived from a combination of rain-gauge observations and satellite estimates. The investigation is based on the period 1961–2001 for the ‘short rains’ season of eastern Africa of October through to December. The EOF analysis was supplemented by projection of National Centers for Environmental Prediction wind data onto the rainfall eigenmodes to understand the rainfall–circulation relationships. Furthermore, correlation and composite analyses have been performed with the Climatic Research Unit globally averaged surface-temperature time series to explore the potential relationship between the climate of eastern Africa and global warming. The most dominant mode of variability (EOF1) based on CMAP data over eastern Africa corresponds to El Niño–southern oscillation (ENSO) climate variability. It is associated with above-normal rainfall amounts during the short rains throughout the entire region, except for Sudan. The corresponding anomalous low-level circulation is dominated by easterly inflow from the Indian Ocean, and to a lesser extent the Congo tropical rain forest, into the positive rainfall anomaly region that extends across most of eastern Africa. The easterly inflow into eastern Africa is part of diffluent outflow from the maritime continent during the warm ENSO events. The second eastern African EOF (trend mode) is associated with decadal variability. In distinct contrast from the ENSO mode pattern, the trend mode is characterized by positive rainfall anomalies over the northern sector of eastern Africa and opposite conditions over the southern sector. This rainfall trend mode eluded detection in previous studies that did not include recent decades of data, because the signal was still relatively weak. The wind projection onto this mode indicates that the primary flow that feeds the positive anomaly region over the northern part of eastern Africa emanates primarily from the rainfall-deficient southern region of eastern Africa and Sudan. Although we do not assign attribution of the trend mode to global warming (in part because of the relatively short period of analysis), the evidence, based on our results and previous studies, strongly suggests a potential connection. Copyright © 2004 Royal Meteorological Society.
DA - 2004/5//
PY - 2004/5//
DO - 10.1002/joc.1019
VL - 24
IS - 6
SP - 681-701
SN - 1097-0088
KW - eastern Africa
KW - climate variability
KW - climate change
KW - CMAP
KW - El Nino-southern oscillation
KW - Greater Horn of Africa
KW - Indian Ocean
KW - zonal mode
ER -
TY - JOUR
TI - Probabilistic methods for addressing uncertainty and variability in biological models: application to a toxicokinetic model
AU - Banks, HT
AU - Potter, LK
T2 - MATHEMATICAL BIOSCIENCES
AB - Population variability and uncertainty are important features of biological systems that must be considered when developing mathematical models for these systems. In this paper we present probability-based parameter estimation methods that account for such variability and uncertainty. Theoretical results that establish well-posedness and stability for these methods are discussed. A probabilistic parameter estimation technique is then applied to a toxicokinetic model for trichloroethylene using several types of simulated data. Comparison with results obtained using a standard, deterministic parameter estimation method suggests that the probabilistic methods are better able to capture population variability and uncertainty in model parameters.
DA - 2004/12//
PY - 2004/12//
DO - 10.1016/j.mbs.2004.11.008
VL - 192
IS - 2
SP - 193-225
SN - 1879-3134
KW - parameter estimation
KW - biological modeling
KW - population variability
KW - model uncertainty
KW - toxicokinetics
KW - trichloroethylene
ER -
TY - JOUR
TI - Concise and accurate solutions to half-space binary-gas flow problems defined by the McCormack model and specular-diffuse wall conditions
AU - Siewert, CE
AU - Valougerogis, D
T2 - EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
AB - An analytical version of the discrete-ordinates method (the ADO method) is used to establish concise and particularly accurate solutions to the viscous-slip and the half-space thermal-creep problems for a binary gas mixture. The kinetic equations used to describe the flow are based on the McCormack model for mixtures. In addition to a computation of the viscous-slip and thermal-slip coefficients, for the case of Maxwell boundary conditions for each of the two species, the velocity, heat-flow and shear-stress profiles are established for both types of particles. Numerical results are reported for three binary mixtures (Ne–Ar, He–Ar and He–Xe) with various molar concentrations. The complete solution requires only a (matrix) eigenvalue/eigenvector routine and the solution of a system of linear algebraic equations, and thus the algorithm is considered especially easy to use. The developed (FORTRAN) code requires typically less than 0.1 seconds on a 1.2 GHz Pentium-based PC to solve both problems.
DA - 2004///
PY - 2004///
DO - 10.1016/j.euromechflu.2003.12.002
VL - 23
IS - 5
SP - 709-726
SN - 0997-7546
ER -
TY - JOUR
TI - Volume determination for bulk materials in bunkers
AU - Ahmed, SA
AU - Buckingham, R
AU - Gremaud, PA
AU - Hauck, CD
AU - Kuster, CM
AU - Prodanovic, M
AU - Royal, TA
AU - Silantyev, V
T2 - INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
AB - A simple model for the determination of the shape of large granular piles in complicated geometries is discussed. An eikonal formulation of the problem is proposed. Two distinct cases arise. In cylindrical geometries, i.e., if both container and possible obstacles have vertical walls, the problem is equivalent to a two-dimensional travel time problem with obstacles, while in general geometries, this analogy breaks down. In the first case, classical one-sided discretizations are generalized to handle obstacles without loss in accuracy. In the second case, a fast and efficient numerical method is proposed, implemented and tested. The discrete problems are solved through fast marching.
DA - 2004/12/7/
PY - 2004/12/7/
DO - 10.1002/nme.1144
VL - 61
IS - 13
SP - 2239-2249
SN - 0029-5981
KW - granular
KW - eikonal formulation
KW - ordered upwind methods
ER -
TY - JOUR
TI - Time reversal for dispersive waves in random media
AU - Fouque, JP
AU - Garnier, J
AU - Nachbin, A
T2 - SIAM JOURNAL ON APPLIED MATHEMATICS
AB - Refocusing for time reversed waves propagating in disordered media has recently been observed experimentally and studied mathematically. This surprising effect has many potential applications in domains such as medical imaging, underwater acoustics, and wireless communications. Time refocusing for one-dimensional acoustic waves is now mathematically well understood. In this paper the important case of one-dimensional dispersive waves is addressed. Time reversal is studied in reflection and in transmission. In both cases we derive the self-averaging properties of time reversed refocused pulses. An asymptotic analysis allows us to derive a precise description of the combined effects of randomness and dispersion. In particular, we study an important regime in transmission, where the coherent front wave is destroyed while time reversal of the incoherent transmitted wave still enables refocusing.
DA - 2004///
PY - 2004///
DO - 10.1137/S0036139903422371
VL - 64
IS - 5
SP - 1810-1838
SN - 1095-712X
KW - dispersive waves
KW - inhomogeneous media
KW - asymptotic theory
KW - time reversal
ER -
TY - JOUR
TI - The McCormack model for gas mixtures: Heat transfer in a plane channel
AU - Garcia, RDM
AU - Siewert, CE
T2 - PHYSICS OF FLUIDS
AB - An analytical version of the discrete-ordinates method (the ADO method) is used to establish a concise and particularly accurate solution to the heat-transfer problem in a plane channel for a binary gas mixture described by the McCormack kinetic model. The solution yields for the general (specular-diffuse) case of Maxwell boundary conditions for each of the two species, the density and temperature profiles for both types of particles, as well as the overall heat flow associated with each of the two species of gas particles. Numerical results are reported for two binary mixtures (Ne–Ar and He–Xe). The algorithm is considered especially easy to use, and the developed (FORTRAN) code requires typically less than a second on a 2.2 GHz Pentium 4 machine to compute all quantities of interest.
DA - 2004/9//
PY - 2004/9//
DO - 10.1063/1.1773711
VL - 16
IS - 9
SP - 3393-3402
SN - 1070-6631
ER -
TY - JOUR
TI - Symmetry reduction of sh-Lie structures and of local functionals
AU - Al-Ashhab, S
T2 - DIFFERENTIAL GEOMETRY AND ITS APPLICATIONS
AB - Reduced sh-Lie structures have been studied for the case when a Lie group acts on the fibers of a vector bundle while preserving the base space of the bundle. In this paper we investigate how one obtains a reduced sh-Lie structure using the ideas of symmetry reduction where the action of the Lie group is transversal to the fibers of the bundle. We also show how local functionals are reduced using these ideas.
DA - 2004/9//
PY - 2004/9//
DO - 10.1016/j.difgeo.2004.05.002
VL - 21
IS - 2
SP - 215-227
SN - 1872-6984
KW - reduction
KW - sh-lie algebra
KW - jet bundle
KW - Poisson bracket
ER -
TY - JOUR
TI - Reconstruction of magnetic charge densities using regularization of bounded variations under noisy observations
AU - Kojima, F
AU - Ito, K
T2 - INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS
AB - This paper is concerned with computational and regularization techniques for recovering induced magnetic fields due to the existence of cracks. The problem is formulated as an inverse problem with a set of source functions of the distribution type. The regularization of bounded variation is effectively used for solving the severe ill-posed problem. A iterative solver is proposed by a integro-differential equation with time marching scheme. For the practical implementation of the numerical treatment, a finite difference scheme is adopted to the proposed method with the aid of discrete fast Fourier transform. Some successful numerical experiments are demonstrated for the validity of the proposed method.
DA - 2004///
PY - 2004///
DO - 10.3233/jae-2004-582
VL - 19
IS - 1-4
SP - 309-313
SN - 1383-5416
KW - inverse problem
KW - regularization
KW - fast fourier transform
ER -
TY - JOUR
TI - Low temperature saturation of p-n junction laser beam induced current signals
AU - Redfern, DA
AU - Fang, W
AU - Ito, K
AU - Musca, CA
AU - Dell, JM
AU - Faraone, L
T2 - SOLID-STATE ELECTRONICS
AB - To date, most studies of the use of laser beam induced current (LBIC) for non-destructive characterisation of photodiodes have been qualitative and/or empirical, due in part to the difficulty of isolating the influence of the large number of material and device parameters on which the LBIC signal is dependent. The development of methodologies whereby these parameters can be determined quantitatively from the LBIC measurements is important for the technique to gain wider acceptance. This work describes, for the first time, the specific experimental conditions under which some of the variable parameters can be eliminated, substantially reducing the complexity of the analysis. In particular, temperature dependence of the peak-to-peak LBIC measurements on p–n junctions is examined for the first time, revealing that a saturation state is reached at low temperatures. When measurements are performed under these saturation conditions, the peak-to-peak LBIC signal becomes independent of doping density and bulk recombination parameters, allowing other parameters including device geometry to be examined with less ambiguity. This concept represents a crucial step towards a quantitative procedure for extraction of p–n junction material and device parameters using LBIC.
DA - 2004/3//
PY - 2004/3//
DO - 10.1016/j.sse.2003.09.008
VL - 48
IS - 3
SP - 409-414
SN - 1879-2405
KW - laser beam induced current
KW - LBIC
KW - photodiode
KW - non-destructive characterisation
KW - temperature dependence
ER -
TY - JOUR
TI - Existence-uniqueness and monotone approximation for an erythropoiesis age-structured model
AU - Ackleh, AS
AU - Deng, K
AU - Cole, CE
AU - Tran, HT
T2 - JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
AB - We develop a monotone approximation to the solution of an age-structured model which describes the regulation of erythropoiesis, the process in which red blood cells are developed. The convergence of this approximation to the unique solution of the model is also established.
DA - 2004/1/15/
PY - 2004/1/15/
DO - 10.1016/j.jmaa.2003.08.037
VL - 289
IS - 2
SP - 530-544
SN - 0022-247X
KW - erythropoiesis
KW - age-structured model
KW - monotone approximation
KW - existence uniqueness
ER -
TY - JOUR
TI - A radial biphasic model for local cell-matrix mechanics in articular cartilage
AU - Haider, MA
T2 - SIAM JOURNAL ON APPLIED MATHEMATICS
AB - Analytical and numerical solutions are presented for an interface problem that models deformation in the local cell-matrix unit (chondron) of articular cartilage. The cell and its protective pericellular matrix layer are modeled as isotropic biphasic continua deforming in small strain. A spherical geometry with purely radial deformation is assumed. Enforcement of the boundary and interface conditions results in an eigenvalue problem that is self-adjoint when the permeabilities of the cell and the layer are the same. In this case, a series solution of the interface problem is presented for a time-varying displacement prescribed at the boundary of the pericellular layer. The case of nonuniform permeability is considered via a numerical finite difference solution. The analytical and numerical solutions are used to conduct a parametric analysis of mechanical signal transmission due to an applied sinusoidal displacement. The dual role of the pericellular matrix as a mechanical signal transmitter and a protective layer is analyzed. For frequencies in the range 0-3Hz, transmission of transient-free radial displacement, solid stress, and strain are evaluated with varying pericellular stiffness and permeability in biphasic models of normal and osteoarthritic chondrons.
DA - 2004///
PY - 2004///
DO - 10.1137/S0036139902417700
VL - 64
IS - 5
SP - 1588-1608
SN - 0036-1399
KW - articular cartilage
KW - chondrocyte
KW - chondron
KW - pericellular matrix
KW - cartilage mechanics
KW - mechanical signal transduction
KW - biphasic theory
KW - interface problem
KW - eigenvalue problem
ER -
TY - JOUR
TI - Testing the nearest Kronecker product preconditioner on Markov chains and stochastic automata networks
AU - Langville, AN
AU - Stewart, WJ
T2 - INFORMS JOURNAL ON COMPUTING
AB - This paper is the experimental follow-up to Langville and Stewart (2002), where the theoretical background for the nearest Kronecker product (NKP) preconditioner was developed. Here we test the NKP preconditioner on both Markov chains (MCs) and stochastic automata networks (SANs). We conclude that the NKP preconditioner is not appropriate for general MCs, but is very effective for a MC stored as a SAN.
DA - 2004///
PY - 2004///
DO - 10.1287/ijoc.1030.0041
VL - 16
IS - 3
SP - 300-315
SN - 1526-5528
KW - probability
KW - Markov processes
KW - queues
KW - Markovian
KW - algorithms
ER -
TY - JOUR
TI - On-bark behavior of Dendroctonus frontalis: a Markov chain analysis
AU - Bishir, J
AU - Roberds, JH
AU - Strom, BL
T2 - JOURNAL OF INSECT BEHAVIOR
DA - 2004/5//
PY - 2004/5//
DO - 10.1023/B:JOIR.0000031531.07035.10
VL - 17
IS - 3
SP - 281-301
SN - 0892-7553
KW - Scolytidae
KW - southern pine beetle
KW - host selection
KW - host recognition
KW - transition probabilities
KW - absorbing states
ER -
TY - JOUR
TI - Design of an electron gun using computer optimization
AU - Lewis, BM
AU - Tran, HT
AU - Read, ME
AU - Ives, RL
T2 - IEEE TRANSACTIONS ON PLASMA SCIENCE
AB - This paper considers an optimization technique in which the objective is attained via alterations to the physical geometry of the system. This optimization framework, to be considered in the context of electron guns, is known as optimal shape design. Optimal shape design has been used in a number of applications including wing design, magnetic tape design, and nozzle design, among others. In this investigation, we use the methods of shape optimization to design the cathode of an electron gun. The dynamical equations modeling the electron particle path as well as the generalized shape optimization problem will be presented. Illustrative examples of the technique on gun designs that were previously limited to spherical cathodes will be given.
DA - 2004/6//
PY - 2004/6//
DO - 10.1109/TPS.2004.827572
VL - 32
IS - 3
SP - 1242-1250
SN - 1939-9375
KW - cathode shape optimization
KW - electron gun
KW - optimal shape design
KW - optimization techniques
ER -
TY - JOUR
TI - Mobius function on cross-section lattices
AU - Putcha, MS
T2 - JOURNAL OF COMBINATORIAL THEORY SERIES A
AB - Let M be an irreducible algebraic monoid with a reductive unit group G . Then there is an idempotent cross-section Λ of G × G -orbits that preserves the Zariski closure ordering. The purpose of this paper is to compute the Möbius function on the cross-section lattice Λ . This is accomplished by analyzing an associated boolean family of face lattices of polytopes and then solving a resulting system of linear equations.
DA - 2004/5//
PY - 2004/5//
DO - 10.1016/j.jcta.2004.03.001
VL - 106
IS - 2
SP - 287-297
SN - 0097-3165
KW - Mobius function
KW - cross section lattice
KW - reductive monoid
ER -
TY - JOUR
TI - Computation of Riemann solutions using the Dafermos regularization and continuation
AU - Schecter, S.
AU - Plohr, B. J.
AU - Marchesin, D.
T2 - Discrete and Continuous Dynamical Systems
AB - We present a numerical method, based on the Dafermos regularization,for computing a one-parameter family of Riemann solutions of a system ofconservation laws. The family is obtained by varying either the left orright state of the Riemann problem. The Riemann solutions are requiredto have shock waves that satisfy the viscous profile criterion prescribedby the physical model. The system is not required to satisfy strict hyperbolicity or genuine nonlinearity; the left and right states need not be close; and the Riemann solutions may contain an arbitrary number of waves, including composite waves and nonclassical shock waves. The method uses standard continuation softwareto solve a boundary-value problem in which the left and right states ofthe Riemann problem appear as parameters. Because the continuation methodcan proceed around limit point bifurcations, it can sucessfully computemultiple solutions of a particular Riemann problem, including ones thatcorrespond to unstable asymptotic states of the viscous conservation laws.
DA - 2004///
PY - 2004///
DO - 10.3934/dcds.2004.10.965
VL - 10
IS - 4
SP - 965-986
ER -
TY - JOUR
TI - An immersed finite element space and its approximation capability
AU - Li, Z.
AU - Lin, T.
AU - Lin, Y.
AU - Rogers, R. C.
T2 - Numerical Methods for Partial Differential Equations
AB - This article discusses an immersed finite element (IFE) space introduced for solving a second-order elliptic boundary value problem with discontinuous coefficients (interface problem). The IFE space is nonconforming and its partition can be independent of the interface. The error estimates for the interpolation of a function in the usual Sobolev space indicate that this IFE space has an approximation capability similar to that of the standard conforming linear finite element space based on body-fit partitions. Numerical examples of the related finite element method based on this IFE space are provided. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 338–367, 2004
DA - 2004///
PY - 2004///
DO - 10.1002/num.10092
VL - 20
IS - 3
SP - 338-367
J2 - Numer. Methods Partial Differential Eq.
LA - en
OP -
SN - 0749-159X 1098-2426
UR - http://dx.doi.org/10.1002/num.10092
DB - Crossref
KW - interface problems
KW - immersed interface
KW - finite element
KW - error estimates
ER -
TY - JOUR
TI - A coupled regional climate model for the Lake Victoria basin of East Africa
AU - Song, Y
AU - Semazzi, FHM
AU - Xie, L
AU - Ogallo, LJ
T2 - INTERNATIONAL JOURNAL OF CLIMATOLOGY
AB - A nested coupled model has been developed to investigate the two-way interactions between the regional climate of eastern Africa and Lake Victoria. The atmospheric component of the model is the North Carolina State University (NCSU) version of the National Center for Atmospheric Research (NCAR) regional climate model (NCSU-RegCM2). The lake component of the model is based on the Princeton ocean model (POM). Three simulations, each 4 months long, have been performed for the short rains of eastern Africa of September through to December. The control experiment is based on the standard NCSU-RegCM2 model coupled to a one-dimensional model of Lake Victoria. The second experiment was based on the stand-alone three-dimensional primitive equation POM–Lake Victoria model forced by output from the atmospheric component of the control run. The third experiment is based on the integration of the coupled system of the NCSU-RegCM2 model where the one-dimensional lake model in the control run has been replaced by the three-dimensional POM hydrodynamical model for Lake Victoria. The results confirm that adopting the traditional modelling approach, in which the lake hydrodynamics are neglected and the formulation is based entirely on thermodynamics alone, is not entirely satisfactory for the Lake Victoria basin. Such a strategy precludes the transport of heat realistically within the lake, from the heat surplus regions to the cooler regions, and thereby results in a degraded simulation of the climate downstream over the rest of the lake and the surrounding land regions. The numerical simulations show that the southwestern region of the lake is an important source of warm water because it is relatively shallower and the water column is heated up much more quickly during the day than the rest of the lake. The result is that the surface temperature anomaly field from the all-lake area average consists of a gradient pattern with warmer water over the shallow region of the lake over the southeastern sector and a colder pool of water over the northeastern region, where the lake is relatively deeper. This pattern is also reproduced by the one-dimensional lake model. Some of the excess heat over the southeastern region is transported to the colder and deeper region over the northeastern part of the lake by prevailing surface wind flow. Through the lake–atmosphere coupling, the resulting asymmetric lake-surface temperature distribution modifies the overlying wind circulation, which in turn reduces the cloud cover and rainfall. This secondary feature in the surface temperature structure cannot be generated by the traditional nested climate models, such as the standard version of the NCAR-RegCM2 model, since the simple static lake model formulation is not capable of supporting horizontal mixing of water. Comparisons show that this feature is weaker in the RegCM2-POM coupled model than the corresponding pattern that we obtained in our previous study based on the ‘stand-alone’ POM lake model. In contrast, from the simple classical text-book theoretical model of the lake–land breeze phenomena, the simulated surface wind circulation and rainfall distribution are highly asymmetric across the lake. Copyright © 2004 Royal Meteorological Society
DA - 2004/1//
PY - 2004/1//
DO - 10.1002/joc.983
VL - 24
IS - 1
SP - 57-75
SN - 1097-0088
KW - Lake Victoria
KW - regional climate modelling
KW - eastern Africa
KW - climate variability
KW - RegCM2
KW - POM
ER -
TY - JOUR
TI - The temperature-jump problem based on the CES model of the linearized Boltzmann equation
AU - Siewert, CE
T2 - ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK
DA - 2004/1//
PY - 2004/1//
DO - 10.1007/s00033-003-1140-x
VL - 55
IS - 1
SP - 92-104
SN - 1420-9039
KW - Boltzmann equation
KW - rarefied gas dynamics
KW - temperature-jump problem
ER -
TY - JOUR
TI - Spatiotemporal dynamics of epidemics: synchrony in metapopulation models
AU - Lloyd, AL
AU - Jansen, VAA
T2 - MATHEMATICAL BIOSCIENCES
AB - Multi-patch models - also known as metapopulation models - provide a simple framework within which the role of spatial processes in disease transmission can be examined. An n-patch model which distinguishes between k different classes of individuals is considered. The linear stability of spatially homogeneous solutions of such models is studied using an extension of an analysis technique previously described for a population setting in which individuals migrate between patches according to a simple linear term. The technique considerably simplifies the analysis as it decouples the nk dimensional linearized system into n distinct k-dimensional systems. An important feature of the spatial epidemiological model is that the spatial coupling may involve non-linear terms. As an example of the use of this technique, the dynamical behavior in the vicinity of the endemic equilibrium of a symmetric SIR model is decomposed into spatial modes. For parameter values appropriate for childhood diseases, expressions for the eigenvalues corresponding to in-phase and out-of-phase modes are obtained, and it is shown that the dominant mode of the system is an in-phase mode. Furthermore, the out-of-phase modes are shown to decay much more rapidly than the in-phase mode for a broad range of coupling strengths.
DA - 2004///
PY - 2004///
DO - 10.1016/j.mbs.2003.09.003
VL - 188
IS - 2004 Mar-Apr
SP - 1-16
SN - 1879-3134
KW - epidemiological model
KW - metapopulation
KW - spatial dynamics
KW - linear stability analysis
ER -
TY - JOUR
TI - Probabilities of extinction, weak extinction permanence, and mutual exclusion in discrete, competitive, Lotka-Volterra systems
AU - Chan, D. M.
AU - Franke, J. E.
T2 - Computers & Mathematics With Applications
DA - 2004///
PY - 2004///
DO - 10.1016/S0898-1221(04)00018-5
VL - 47
IS - 03-Feb
SP - 365-379
ER -
TY - JOUR
TI - On computing the Chapman-Enskog and Burnett functions
AU - Barichello, LB
AU - Rodrigues, P
AU - Siewert, CE
T2 - JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
AB - An expansion and projection technique based on Legendre polynomials is used to solve, in an efficient and accurate way, the Chapman-Enskog equations for viscosity and heat transfer and to compute the Burnett functions required, for example, for Poiseuille-flow problems based on rigid-sphere collisions and the linearized Boltzmann equation.
DA - 2004/6/1/
PY - 2004/6/1/
DO - 10.1016/j.jqsrt.2003.10.001
VL - 86
IS - 1
SP - 109-114
SN - 1879-1352
KW - Boltzmann equation
KW - rarefied-gas dynamics
KW - Chapman-Enskog
KW - Burnett
ER -
TY - JOUR
TI - Gradient flow methods for matrix completion with prescribed eigenvalues
AU - Chu, MT
AU - Diele, F
AU - Sgura, I
T2 - LINEAR ALGEBRA AND ITS APPLICATIONS
AB - Matrix completion with prescribed eigenvalues is a special type of inverse eigenvalue problem. The goal is to construct a matrix subject to both the structural constraint of prescribed entries and the spectral constraint of prescribed spectrum. The challenge of such a completion problem lies in the intertwining of the cardinality and the location of the prescribed entries so that the inverse problem is solvable. An intriguing question is whether matrices can have arbitrary entries at arbitrary locations with arbitrary eigenvalues and how to complete such a matrix. Constructive proofs exist to a certain point (and those proofs, such as the classical Schur–Horn theorem, are amazingly elegant enough in their own right) beyond which very few theories or numerical algorithms are available. In this paper the completion problem is recast as one of minimizing the distance between the isospectral matrices with the prescribed eigenvalues and the affined matrices with the prescribed entries. The gradient flow is proposed as a numerical means to tackle the construction. This approach is general enough that it can be used to explore the existence question when the prescribed entries are at arbitrary locations with arbitrary cardinalities.
DA - 2004/3/1/
PY - 2004/3/1/
DO - 10.1016/S0024-3795(03)00393-8
VL - 379
IS - 1-3 SPEC. ISS
SP - 85-112
SN - 1873-1856
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0742268367&partnerID=MN8TOARS
KW - matrix completion
KW - inverse eigenvalue problem
KW - prescribed entries
KW - isospectral matrices
KW - gradient flow
KW - ODE solvers
KW - restart
ER -
TY - JOUR
TI - Computing the sign or the value of the determinant of an integer matrix, a complexity survey
AU - Kaltofen, E
AU - Villard, G
T2 - JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
AB - Computation of the sign of the determinant of a matrix and the determinant itself is a challenge for both numerical and exact methods. We survey the complexity of existing methods to solve these problems when the input is an n×n matrix A with integer entries. We study the bit-complexities of the algorithms asymptotically in n and the norm of A. Existing approaches rely on numerical approximate computations, on exact computations, or on both types of arithmetic in combination.
DA - 2004/1/1/
PY - 2004/1/1/
DO - 10.1016/j.cam.2003.08.019
VL - 162
IS - 1
SP - 133-146
SN - 1879-1778
KW - determinant
KW - bit-complexity
KW - integer matrix
KW - approximate computation
KW - exact computation
KW - randomized algorithms
ER -
TY - JOUR
TI - Altered flower retention and developmental patterns in nine tomato cultivars under elevated temperature
AU - Sato, S
AU - Peet, MM
AU - Gardner, RG
T2 - SCIENTIA HORTICULTURAE
AB - Moderately elevated temperature effects on flower development were examined in nine tomato cultivars (Lycopersicon esculentum Mill.). Plants were grown under high (HT, 32/28 °C day/night temperatures) and control (CT, 26/22 °C) temperature conditions. Fate of flowers developed was categorized as seeded fruit, parthenocarpic fruit, undeveloped flowers, or aborted flowers. Although HT decreased seeded fruit set in all nine cultivars, the degree of sensitivity and the pattern of reaction to the elevated temperature differed among cultivars. FLA7156 was the most tolerant cultivar, although under HT seeded fruit set was less than half that at CT (22.5% compared to 46.8%). The remaining cultivars had very few or no seeded fruit set at all at HT. The percentage of parthenocarpic fruit increased at HT compared to CT in all cultivars. Aborted flowers also increased in FLA7156, NC8288, NCHS1 and NC46E, but did not change in ‘Piedmont’, NC279HS, and NC403HS, or decreased in ‘Fresh Market 9’ and TH318. Reduction of flower abortion and increase of parthenocarpic fruit set can be advantageous traits for breeding of high temperature tolerant tomato cultivars.
DA - 2004/5/3/
PY - 2004/5/3/
DO - 10.1016/j.scienta.2003.10.008
VL - 101
IS - 1-2
SP - 95-101
SN - 0304-4238
KW - Lycopersicon esculentum Mill
KW - parthenocarpy
KW - undeveloped flowers
KW - flower abortion
KW - high temperature stress
ER -
TY - JOUR
TI - Global asymptotic stability of Lotka-Volterra competition systems with diffusion and time delays
AU - Pao, CV
T2 - NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
AB - In the Lotka–Volterra competition system with N-competing species if the effect of dispersion and time-delays are both taken into consideration, then the densities of the competing species are governed by a coupled system of reaction–diffusion equations with time-delays. The aim of this paper is to investigate the asymptotic behavior of the time-dependent solution in relation to a positive uniform solution of the corresponding steady-state problem in a bounded domain with Neumann boundary condition, including the existence and uniqueness of a positive steady-state solution. A simple and easily verifiable condition is given to the competing rate constants to ensure the global asymptotic stability of the positive steady-state solution. This result leads to the permanence of the competing system, the instability of the trivial and all forms of semitrivial solutions, and the nonexistence of nonuniform steady-state solution. The condition for the global asymptotic stability is independent of diffusion and time-delays, and the conclusions for the reaction–diffusion system are directly applicable to the corresponding ordinary differential system.
DA - 2004/2//
PY - 2004/2//
DO - 10.1016/S1468-1218(03)00018-X
VL - 5
IS - 1
SP - 91-104
SN - 1468-1218
KW - Lotka-Volterra competition
KW - reaction-diffusion system
KW - ordinary differential system
KW - time-delays
KW - global asymptotic stability
KW - permanence
ER -
TY - JOUR
TI - Estimating variability in models for recurrent epidemics: assessing the use of moment closure techniques
AU - Lloyd, AL
T2 - THEORETICAL POPULATION BIOLOGY
AB - The major role played by demographic stochasticity in determining the dynamics and persistence of childhood diseases, such as measles, chickenpox and pertussis, has long been realized. Techniques which can be used to estimate the magnitude of this stochastic effect are of clear importance. In this study, we assess and compare the use of two moment closure approximations to estimate the variability seen about the average behavior of stochastic models for the recurrent epidemics seen in childhood diseases. The performance of the approximations are assessed using analytic techniques available for the simplest epidemiological model and using numerical simulations in more complex settings. We also present epidemiologically important extensions of previous work, considering variability in the SEIR model and in situations for which there is seasonal variation in disease transmission. Important implications of stochastic effects for the dynamics of childhood diseases are highlighted, including serious deficiencies of deterministic descriptions of dynamical behavior.
DA - 2004/2//
PY - 2004/2//
DO - 10.1016/j.tpb.2003.07.002
VL - 65
IS - 1
SP - 49-65
SN - 1096-0325
KW - demographic stochasticity
KW - moment closure
KW - epidemic models
KW - nonlinear dynamics
ER -
TY - JOUR
TI - U-q (gl(N)) action on gl(N)-modules and quantum toroidal algebras
AU - Gao, Y
AU - Jing, NH
T2 - JOURNAL OF ALGEBRA
AB - We construct an explicit realization of the quantum toroidal algebra U q ( sl N, tor ) on the basic module for the affine Lie algebra gl N based on a modified version of the quantum affine algebra U q ( gl N ) .
DA - 2004/3/1/
PY - 2004/3/1/
DO - 10.1016/j.jalgebra.2003.09.046
VL - 273
IS - 1
SP - 320-343
SN - 0021-8693
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1342268342&partnerID=MN8TOARS
ER -
TY - BOOK
TI - Auxiliary Signal Design for Failure Detection
AU - Campbell, Stephen L.
AU - Nikoukhah, Ramine
CN - TA169.5 .C36 2004
DA - 2004/1//
PY - 2004/1//
DO - 10.1515/9781400880041
PB - Princeton University Press
SN - 0691099871
ER -
TY - JOUR
TI - On deriving lumped models for blood flow and pressure in the systemic arteries
AU - Olufsen, MS
AU - Nadim, A
T2 - MATHEMATICAL BIOSCIENCES AND ENGINEERING
AB - Windkessel and similar lumped models are often used to represent blood flow and pressure in systemic arteries. The windkessel model was originally developed by Stephen Hales (1733) and Otto Frank (1899) who used it to describe blood flow in the heart. In this paper we start with the one-dimensional axisymmetric Navier-Stokes equations for time-dependent blood flow in a rigid vessel to derive lumped models relating flow and pressure. This is done through Laplace transform and its inversion via residue theory. Upon keeping contributions from one, two, or more residues, we derive lumped models of successively higher order. We focus on zeroth, first and second order models and relate them to electrical circuit analogs, in which current is equivalent to flow and voltage to pressure. By incorporating e ffects of compliance through addition of capacitors, windkessel and related lumped models are obtained. Our results show that given the radius of a blood vessel, it is possible to determine the order of the model that would be appropriate for analyzing the flow and pressure in that vessel. For instance, in small rigid vessels ($R <$ 0.2 cm) it is adequate to use Poiseuille's law to express the relation between flow and pressure, whereas for large vessels it might be necessary to incorporate spatial dependence by using a one-dimensional model accounting for axial variations.
DA - 2004/6//
PY - 2004/6//
DO - 10.3934/mbe.2004.1.61
VL - 1
IS - 1
SP - 61-80
SN - 1551-0018
KW - arterial modeling
KW - lumped arterial models
ER -
TY - JOUR
TI - Unitary partitioning in general constraint preserving DAE integrators
AU - Arevalo, C
AU - Campbell, SL
AU - Selva, M
T2 - MATHEMATICAL AND COMPUTER MODELLING
AB - A number of numerical algorithms have been developed for various special classes of DAEs. This paper describes a new variable step size, constraint preserving integrator for general nonlinear fully implicit higher index DAEs. Numerical implementation issues are discussed. Numerical examples illustrate the effectiveness of the new method.
DA - 2004/12//
PY - 2004/12//
DO - 10.1016/j.mcm.2005.01.018
VL - 40
IS - 11-12
SP - 1273-1284
SN - 0895-7177
KW - differential algebraic equati ons
KW - numerical integration
KW - constraint preservation
KW - singular system
ER -
TY - JOUR
TI - Symmetric nonbarotropic flows with large data and forces
AU - Hoff, D
AU - Jenssen, HK
T2 - ARCHIVE FOR RATIONAL MECHANICS AND ANALYSIS
AB - We prove the global existence of weak solutions of the Navier-Stokes equations of compressible, nonbarotropic flow in three space dimensions with initial data and external forces which are large, discontinuous, and spherically or cylindrically symmetric. The analysis allows for the possibility that a vacuum state emerges at the origin or axis of symmetry, and the equations hold in the sense of distributions in the set where the density is positive. In addition, the mass and momentum equations hold weakly in the entire space-time domain, but with a nonstandard interpretation of the viscosity terms as distributions. Solutions are obtained as limits of solutions in annular regions between two balls or cylinders, and the analysis allows for the possibility that energy is absorbed into the origin or axis, and is lost in the limit as the inner radius goes to zero.
DA - 2004/9//
PY - 2004/9//
DO - 10.1007/s00205-004-0318-5
VL - 173
IS - 3
SP - 297-343
SN - 0003-9527
ER -
TY - JOUR
TI - Simulation of the sensitivity of Lake Victoria basin climate to lake surface temperatures
AU - Anyah, RO
AU - Semazzi, FHM
T2 - THEORETICAL AND APPLIED CLIMATOLOGY
DA - 2004/10//
PY - 2004/10//
DO - 10.1007/s00704-004-0057-4
VL - 79
IS - 1-2
SP - 55-69
SN - 1434-4483
ER -
TY - JOUR
TI - On the computation of steady Hopper flows II: von Mises materials in various geometries
AU - Gremaud, PA
AU - Matthews, JV
AU - M O'Malley,
T2 - JOURNAL OF COMPUTATIONAL PHYSICS
AB - Similarity solutions are constructed for the flow of granular materials through hoppers. Unlike previous work, the present approach applies to nonaxisymmetric containers. The model involves ten unknowns (stresses, velocity, and plasticity function) determined by nine nonlinear first order partial differential equations together with a quadratic algebraic constraint (yield condition). A pseudospectral discretization is applied; the resulting problem is solved with a trust region method. The important role of the hopper geometry on the flow is illustrated by several numerical experiments of industrial relevance.
DA - 2004/11/1/
PY - 2004/11/1/
DO - 10.1016/j.jcp.2004.04.021
VL - 200
IS - 2
SP - 639-653
SN - 1090-2716
KW - elliptic
KW - granular
KW - similarity
KW - spectral
ER -
TY - JOUR
TI - On a hybrid finite-volume-particle method
AU - Chertock, A
AU - Kurganov, A
T2 - ESAIM-MATHEMATICAL MODELLING AND NUMERICAL ANALYSIS-MODELISATION MATHEMATIQUE ET ANALYSE NUMERIQUE
AB - We present a hybrid finite-volume-particle numerical method for computing the transport of a passive pollutant by a flow. The flow is modeled by the one- and two-dimensional Saint-Venant system of shallow water equations and the pollutant propagation is described by a transport equation. This paper is an extension of our previous work [Chertock, Kurganov and Petrova, J. Sci. Comput. (to appear)], where the one-dimensional finite-volume-particle method has been proposed. The core idea behind the finite-volume-particle method is to use different schemes for the flow and pollution computations: the shallow water equations are numerically integrated using a finite-volume scheme, while the transport equation is solved by a particle method. This way the specific advantages of each scheme are utilized at the right place. A special attention is given to the recovery of the point values of the numerical solution from its particle distribution. The reconstruction is obtained using a dual equation for the pollutant concentration. This results in a significantly enhanced resolution of the computed solution and also makes it much easier to extend the finite-volume-particle method to the two-dimensional case.
DA - 2004///
PY - 2004///
DO - 10.1051/m2an:2004051
VL - 38
IS - 6
SP - 1071-1091
SN - 1290-3841
UR - https://doi-org.prox.lib.ncsu.edu/10.1051/m2an:2004051
KW - shallow water equations
KW - transport of passive pollutant
KW - finite-volume schemes
KW - particle method
ER -
TY - JOUR
TI - Nonlinear reptation in molecular based hysteresis models for polymers
AU - Banks, HT
AU - Medhin, NG
AU - Pinter, GA
T2 - QUARTERLY OF APPLIED MATHEMATICS
AB - We extend the linear “stick-slip” models of Doi-Edwards and Johnson-Stacer to nonlinear tube reptation models. We then show that such models, when combined with probabilistic formulations allowing distributions of relaxation times, provide a good description of dynamic experiments with highly filled rubber in tensile deformations. A connection to other applications including dielectric polarization and reptation in other viscoelastic materials (e.g., living tissue) is noted.
DA - 2004/12//
PY - 2004/12//
DO - 10.1090/qam/2104273
VL - 62
IS - 4
SP - 767-779
SN - 1552-4485
KW - viscoelastic
KW - hysteresis
KW - polymers
KW - molecular models
KW - relaxation times
KW - probability
KW - distributions
KW - uncertainty
ER -
TY - JOUR
TI - High-frequency pulse propagation in nonlinear dielectric materials
AU - Banks, HT
AU - Pinter, GA
T2 - NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
AB - Abstract We consider a variational formulation based on Maxwell's equations for the propagation of high-frequency (gigahertz to terahertz) ultrashort input pulses in dielectric materials modeled by a linear Debye medium. We demonstrate computationally the emergence of Brillouin precursors in the material (water) and the fact that the peak of this transient is attenuated at a much slower rate than is the carrier frequency. In the 0.1– 1 THz regime the carrier frequency does not propagate in our calculations. Only the precursors enter the material, and this is in line with experiments reported by Pleshko and Palocz (Phys. Rev. Lett. 22 (1969) 1201). We also implement models that include nonlinearly forced Debye and nonlinear Debye polarization dynamics and demonstrate the importance of nonlinear effects, especially when the amplitude of the input signal is large. This is an important step in understanding high-frequency pulse propagation, and it has potential applications in the assessment of safety standards and in extending current imaging capabilities in both civilian and military uses.
DA - 2004/9//
PY - 2004/9//
DO - 10.1016/j.nonrwa.2003.10.002
VL - 5
IS - 4
SP - 597-612
SN - 1468-1218
KW - Maxwell's equations
KW - nonlinear dielectrics
KW - terahertz pulse propagation
ER -
TY - JOUR
TI - Bruhat-Chevalley order in reductive monoids
AU - Putcha, MS
T2 - JOURNAL OF ALGEBRAIC COMBINATORICS
AB - Let M be a reductive monoid with unit group G. Let Λ denote the idempotent cross-section of the G × G-orbits on M. If W is the Weyl group of G and e, f ∈ Λ with e ≤ f, we introduce a projection map from WeW to WfW. We use these projection maps to obtain a new description of the Bruhat-Chevalley order on the Renner monoid of M. For the canonical compactification X of a semisimple group G0 with Borel subgroup B0 of G0, we show that the poset of B0 × B0-orbits of X (with respect to Zariski closure inclusion) is Eulerian.
DA - 2004/7//
PY - 2004/7//
DO - 10.1023/B:JACO.0000047291.42015.a6
VL - 20
IS - 1
SP - 33-53
SN - 1572-9192
KW - reductive monoid
KW - Renner monoid
KW - Bruhat-Chevalley order
KW - projections
ER -
TY - JOUR
TI - Behavior dominated by slow particles in a disordered asymmetric exclusion process
AU - Grigorescu, I
AU - Kang, M
AU - Seppalainen, T
T2 - ANNALS OF APPLIED PROBABILITY
AB - We study the large space and time scale behavior of a totally asymmetric, nearest-neighbor exclusion process in one dimension with random jump rates attached to the particles. When slow particles are sufficiently rare, the system has a phase transition. At low densities there are no equilibrium distributions, and on the hydrodynamic scale the initial profile is transported rigidly. We elaborate this situation further by finding the correct order of the correction from the hydrodynamic limit, together with distributional bounds averaged over the disorder. We consider two settings, a macroscopically constant low density profile and the outflow from a large jam.
DA - 2004/8//
PY - 2004/8//
DO - 10.1214/105051604000000387
VL - 14
IS - 3
SP - 1577-1602
SN - 1050-5164
KW - asymmetric exclusion process
KW - hydrodynamic limit
KW - random rates
ER -
TY - JOUR
TI - Well-posedness for a nonsmooth acoustic system
AU - Banks, H. T.
AU - Raye, J. K.
T2 - Applied Mathematics Letters
DA - 2004///
PY - 2004///
DO - 10.1016/S0893-9659(04)00013-8
VL - 17
IS - 3
SP - 317-322
ER -
TY - JOUR
TI - Vertex Representations and McKay Correspondence
AU - Jing, N.
T2 - Algebra Colloquium
DA - 2004///
PY - 2004///
VL - 11
IS - 1
SP - 53-70
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1842528779&partnerID=MN8TOARS
ER -
TY - JOUR
TI - The constraints as evolution equations for numerical relativity
AU - Gentle, AP
AU - George, ND
AU - Kheyfets, A
AU - Miller, WA
T2 - CLASSICAL AND QUANTUM GRAVITY
AB - The Einstein equations have proven surprisingly difficult to solve numerically. A standard diagnostic of the problems which plague the field is the failure of computational schemes to satisfy the constraints, which are known to be mathematically conserved by the evolution equations. We describe a new approach to rewriting the constraints as first-order evolution equations, thereby guaranteeing that they are satisfied to a chosen accuracy by any discretization scheme. This introduces a set of four subsidiary constraints which are far simpler than the standard constraint equations, and which should be more easily conserved in computational applications. We explore the manner in which the momentum constraints are already incorporated in several existing formulations of the Einstein equations, and demonstrate the ease with which our new constraint-conserving approach can be incorporated into these schemes.
DA - 2004/1/7/
PY - 2004/1/7/
DO - 10.1088/0264-9381/21/1/006
VL - 21
IS - 1
SP - 83-91
SN - 0264-9381
ER -
TY - JOUR
TI - Smoothness of quotients associated with a pair of commuting involutions
AU - Helminck, AG
AU - Schwarz, GW
T2 - CANADIAN JOURNAL OF MATHEMATICS-JOURNAL CANADIEN DE MATHEMATIQUES
AB - Abstract Let σ, θ be commuting involutions of the connected semisimple algebraic group G where σ, θ and G are defined over an algebraically closed field , char = 0. Let H := G σ and K := G θ be the fixed point groups. We have an action ( H × K ) × G → G , where (( h , k ), g ) ⟼ hgk –1 , h ∈ H , k ∈ K , g ∈ G . Let G //( H × K ) denote the categorical quotient Spec ( G ) H × K . We determine when this quotient is smooth. Our results are a generalization of those of Steinberg [Ste75], Pittie [Pit72] and Richardson [Ric82] in the symmetric case where σ = θ and H = K .
DA - 2004/10//
PY - 2004/10//
DO - 10.4153/CJM-2004-043-7
VL - 56
IS - 5
SP - 945-962
SN - 1496-4279
ER -
TY - JOUR
TI - Shock structure due to stochastic forcing and the time reversal of nonlinear waves
AU - Fouque, JP
AU - Garnier, J
AU - Nachbin, A
T2 - PHYSICA D-NONLINEAR PHENOMENA
AB - This paper is concerned with the study of the deformation of a nonlinear pulse traveling in a random medium. We consider shallow water waves with a spatially random depth. We demonstrate that in the presence of properly scaled stochastic forcing the solution to the nonlinear conservation law is regularized leading to a viscous shock profile. This enables us to perform time-reversal experiments beyond the critical time for shock formation.
DA - 2004/8/15/
PY - 2004/8/15/
DO - 10.1016/j.physd.2004.05.003
VL - 195
IS - 3-4
SP - 324-346
SN - 1872-8022
KW - nonlinear waves
KW - inhomogeneous media
KW - viscous shock
KW - time reversal
ER -
TY - JOUR
TI - Robustness of time reversal for waves in time-dependent random media
AU - Vigo, DGA
AU - Fouque, JP
AU - Garnier, J
AU - Nachbin, A
T2 - STOCHASTIC PROCESSES AND THEIR APPLICATIONS
AB - This paper addresses the impact of time fluctuations of a random medium on refocusing during a time-reversal experiment. Even in the presence of moderate time perturbations a coherent refocused pulse is observed. The theory predicts the level of recompression observed as well as the conditions for the loss of statistical stabilization. It is shown that the statistical properties of the refocused pulse depend on a simple set of parameters that describe the correlation degree of the medium. The refocused pulse has in general a random shape that can be described in terms of a system of stochastic transport equations driven by a single Brownian motion. Pulse stabilization is also demonstrated for some particular configurations, and the convolution kernel that describes the pulse reshaping is explicitly computed. Numerical simulations are presented and show a very good agreement with the theoretical predictions, thus providing a clear illustration of the robustness of time reversal.
DA - 2004/10//
PY - 2004/10//
DO - 10.1016/j.spa.2004.04.002
VL - 113
IS - 2
SP - 289-313
SN - 1879-209X
KW - inhomogeneous media
KW - asymptotic theory
KW - time reversal
ER -
TY - JOUR
TI - Portfolio optimization models on infinite-time horizon
AU - Pang, T
T2 - JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS
DA - 2004/9//
PY - 2004/9//
DO - 10.1023/B:JOTA.0000042596.26927.2d
VL - 122
IS - 3
SP - 573-597
SN - 1573-2878
KW - portfolio optimization
KW - dynamic programming equations
KW - subsolutions and supersolutions
ER -
TY - JOUR
TI - Optimization of power in the problems of active control of sound
AU - Lončarić, J.
AU - Tsynkov, S.V.
T2 - Mathematics and Computers in Simulation
AB - We analyze the problem of suppressing the unwanted component of a time-harmonic acoustic field (noise) on a predetermined region of interest. The suppression is rendered by active means, i.e., by introducing the additional acoustic sources called controls that generate the appropriate anti-sound. Previously, we have obtained general solutions for active controls in both continuous and discrete formulation of the problem. We have also obtained optimal solutions that minimize the L1 or L2 norm of the control sources; the physical interpretation of the former being the overall absolute acoustic source strength. In the current paper, we minimize the power required for the operation of the active control system. It turns out that the corresponding analysis necessarily involves interaction between the sources of sound and the surrounding acoustic field, which was not the case for either L1 or L2. Even though it may first seem counterintuitive, one can build a control system (a particular combination of surface monopoles and dipoles) that would require no power input for operation and would even produce a net power gain while providing the exact noise cancellation. This usually comes at the expense of having the original sources of noise produce even more energy.
DA - 2004/5//
PY - 2004/5//
DO - 10.1016/j.matcom.2004.01.005
VL - 65
IS - 4-5
SP - 323-335
J2 - Mathematics and Computers in Simulation
LA - en
OP -
SN - 0378-4754
UR - http://dx.doi.org/10.1016/j.matcom.2004.01.005
DB - Crossref
KW - noise cancellation
KW - active control sources
KW - volumetric and surface controls
KW - general solution
KW - monopoles and dipoles
KW - radiation of waves
KW - complex-valued quantities
KW - load on the sources by the field
KW - net power gain
ER -
TY - JOUR
TI - On the nilpotency of certain subalgebras of Kac-Moody Lie algebras
AU - Kim, Y.
AU - Misra, K. C.
AU - Stitzinger, E.
T2 - Journal of Lie Theory
DA - 2004///
PY - 2004///
VL - 14
IS - 1
SP - 23-
ER -
TY - JOUR
TI - On computing the thermal-slip coefficient from Kramers' problem
AU - Siewert, CE
T2 - PHYSICS OF FLUIDS
AB - Classical techniques are used to derive a variant of an Onsager relation (used typically for Poiseuille flow and thermal-creep flow) that yields a convenient relationship between the heat flow of Kramers’ problem and the thermal-slip coefficient. The analysis is based on the linearized Boltzmann equation for rigid-sphere interactions, and wall interactions are described by a general law that includes, for example, the Maxwell model (a mixture of specular and diffuse reflection) and the Cercignani–Lampis model.
DA - 2004/6//
PY - 2004/6//
DO - 10.1063/1.1728157
VL - 16
IS - 6
SP - 2132-2135
SN - 1089-7666
ER -
TY - JOUR
TI - Note on Jacobi's method for approximating dominant roots
AU - Hong, H
T2 - JOURNAL OF SYMBOLIC COMPUTATION
AB - In 1834 Jacobi gave a method for approximating dominant roots of a polynomial. In 2002 Mignotte and Stefanescu showed that Jacobi’s method works only when the dominant roots are simple. In this note, we show that Jacobi’s method can still be useful even when the dominant roots are not simple, if we use it for approximating the “distinct” dominant roots.
DA - 2004/4//
PY - 2004/4//
DO - 10.1016/j.jsc.2003.07.003
VL - 37
IS - 4
SP - 449-453
SN - 0747-7171
UR - http://dx.doi.org/10.1016/j.jsc.2003.07.003
KW - dominant roots
KW - root bounds
ER -
TY - JOUR
TI - Immune responses and the emergence of drug-resistant virus strains in vivo
AU - Wodarz, D
AU - Lloyd, AL
T2 - PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
AB - The treatment of viral infections using antiviral drugs has had a significant public health benefit in the setting of human immunodeficiency virus (HIV) infection, and newly developed drugs offer potential benefits in the management of other viral infections, including acute self-limiting infections such as influenza and picornaviruses (including the rhinoviruses that are responsible for a large proportion of 'common colds'). A serious concern with such treatments is that they may lead to the selection of drug-resistant strains. This has been a significant problem in the case of HIV infection. Existing mathematical-modelling studies of drug resistance have focused on the interactions between virus, target cells and infected cells, ignoring the impact of immune responses. Here, we present a model that explores the role of immune responses in the rise of drug-resistant mutants in vivo. We find that drug resistance is unlikely to be a problem if immune responses are maintained above a threshold level during therapy. Alternatively, if immune responses decline at a fast rate and fall below a threshold level during treatment (indicating impaired immunity), the rise of drug-resistant mutants is more likely. This indicates an important difference between HIV, which impairs immunity and for which immune responses have been observed to vanish during treatment, and viral infections such as influenza and rhinoviruses, for which such immune impairment is not present. Drug resistance is much more likely to be a problem in HIV than in acute and self-limiting infections.
DA - 2004/6/7/
PY - 2004/6/7/
DO - 10.1098/rspb.2003.2664
VL - 271
IS - 1544
SP - 1101-1109
SN - 0962-8452
KW - mathematical models
KW - drug resistance
KW - acute infection
KW - HIV
KW - rhinoviruses
KW - common cold
ER -
TY - JOUR
TI - Hydrodynamic limit for a Fleming-Viot type system
AU - Grigorescu, I
AU - Kang, M
T2 - STOCHASTIC PROCESSES AND THEIR APPLICATIONS
AB - We consider a system of N Brownian particles evolving independently in a domain D . As soon as one particle reaches the boundary it is killed and one of the other particles is chosen uniformly and splits into two independent particles resuming a new cycle of independent motion until the next boundary hit. We prove the hydrodynamic limit for the joint law of the empirical measure process and the average number of visits to the boundary as N approaches infinity.
DA - 2004/3//
PY - 2004/3//
DO - 10.1016/j.spa.2003.10.010
VL - 110
IS - 1
SP - 111-143
SN - 1879-209X
KW - Fleming-Viot
KW - hydrodynamic limit
KW - catalytic branching
KW - absorbing Brownian motion
ER -
TY - JOUR
TI - Constraints in quantum geometrodynamics
AU - Gentle, AP
AU - George, ND
AU - Miller, WA
AU - Kheyfets, A
T2 - INTERNATIONAL JOURNAL OF MODERN PHYSICS A
AB - We compare different treatments of the constraints in canonical quantum gravity. The standard approach on the superspace of 3--geometries treats the constraints as the sole carriers of the dynamic content of the theory, thus rendering the traditional dynamical equations obsolete. Quantization of the constraints in both the Dirac and ADM square root Hamiltonian approaches leads to the well known problems of time evolution. These problems of time are of both an interpretational and technical nature. In contrast, the geometrodynamic quantization procedure on the superspace of the true dynamical variables separates the issues of quantization from the enforcement of the constraints. The resulting theory takes into account states that are off-shell with respect to the constraints, and thus avoids the problems of time. We develop, for the first time, the geometrodynamic quantization formalism in a general setting and show that it retains all essential features previously illustrated in the context of homogeneous cosmologies.
DA - 2004/4/20/
PY - 2004/4/20/
DO - 10.1142/S0217751X04017008
VL - 19
IS - 10
SP - 1609-1638
SN - 0217-751X
KW - quantum gravity
KW - canonical quantum gravity
ER -
TY - JOUR
TI - CLT for linear spectral statistics of large-dimensional sample covariance matrices
AU - Bai, Z. D.
AU - Silverstein, J. W.
T2 - Annals of Probability
DA - 2004///
PY - 2004///
VL - 32
IS - 1A
SP - 553–605
ER -
TY - JOUR
TI - Brauer characters of finite monoids
AU - Putcha, MS
T2 - ALGEBRAS AND REPRESENTATION THEORY
DA - 2004/3//
PY - 2004/3//
DO - 10.1023/B:ALGE.0000019387.07748.9b
VL - 7
IS - 1
SP - 59-66
SN - 1386-923X
KW - monoid
KW - Brauer character
KW - quiver
ER -
TY - JOUR
TI - An application of stochastic control theory to financial economics
AU - Fleming, WH
AU - Pang, T
T2 - SIAM JOURNAL ON CONTROL AND OPTIMIZATION
AB - We consider a portfolio optimization problem which is formulated as a stochastic control problem. Risky asset prices obey a logarithmic Brownian motion, and interest rates vary according to an ergodic Markov diffusion process. The goal is to choose optimal investment and consumption policies to maximize the infinite horizon expected discounted hyperbolic absolute risk aversion (HARA) utility of consumption. A dynamic programming principle is used to derive the dynamic programming equation (DPE). The subsolution--supersolution method is used to obtain existence of solutions of the DPE. The solutions are then used to derive the optimal investment and consumption policies.
DA - 2004///
PY - 2004///
DO - 10.1137/S0363012902419060
VL - 43
IS - 2
SP - 502-531
SN - 1095-7138
KW - portfolio optimization
KW - dynamic programming equations
KW - subsolutions
KW - supersolutions
ER -
TY - JOUR
TI - A fast solver for the Ornstein-Zernike equations
AU - Kelley, CT
AU - Pettitt, BM
T2 - JOURNAL OF COMPUTATIONAL PHYSICS
AB - In this paper, we report on the design and analysis of a multilevel method for the solution of the Ornstein–Zernike Equations and related systems of integro-algebraic equations. Our approach is based on an extension of the Atkinson–Brakhage method, with Newton-GMRES used as the coarse mesh solver. We report on several numerical experiments to illustrate the effectiveness of the method. The problems chosen are related to simple short ranged fluids with continuous potentials. Speedups over traditional methods for a given accuracy are reported. The new multilevel method is roughly six times faster than Newton-GMRES and 40 times faster than Picard.
DA - 2004/7/1/
PY - 2004/7/1/
DO - 10.1016/j.jcp.2003.12.006
VL - 197
IS - 2
SP - 491-501
SN - 1090-2716
ER -
TY - JOUR
TI - The primal-dual active set method for nonlinear optimal control problems with bilateral constraints
AU - Ito, K
AU - Kunisch, K
T2 - SIAM JOURNAL ON CONTROL AND OPTIMIZATION
AB - The primal-dual active set method has proved to be an efficient numerical tool in the context of diverse applications. So far it has been investigated mainly for linear problems. This paper is devoted to the study of global convergence of the primal-dual active set method for nonlinear problems with bilateral constraints. Utilizing the close relationship between the primal-dual active set method and semismooth Newton methods, local superlinear convergence of the method is investigated as well.
DA - 2004///
PY - 2004///
DO - 10.1137/S0363012902411015
VL - 43
IS - 1
SP - 357-376
SN - 1095-7138
KW - primal-dual active set method
KW - semismooth Newton method
KW - optimal control
KW - bilateral constraints
ER -
TY - JOUR
TI - The life and work of A.A. Markov
AU - Basharin, G. P.
AU - Langville, A. N.
AU - Naumov, V. A.
T2 - Linear Algebra and Its Applications
DA - 2004///
PY - 2004///
VL - 386
IS - Jul 15 2004
SP - 26-
ER -
TY - JOUR
TI - The Kronecker product and stochastic automata networks
AU - Langville, AN
AU - Stewart, WJ
T2 - JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
AB - This paper can be thought of as a companion paper to Van Loan's The Ubiquitous Kronecker Product paper (J. Comput. Appl. Math. 123 (2000) 85). We collect and catalog the most useful properties of the Kronecker product and present them in one place. We prove several new properties that we discovered in our search for a stochastic automata network preconditioner. We conclude by describing one application of the Kronecker product, omitted from Van Loan's list of applications, namely stochastic automata networks.
DA - 2004/6/1/
PY - 2004/6/1/
DO - 10.1016/j.cam.2003.10.010
VL - 167
IS - 2
SP - 429-447
SN - 1879-1778
KW - stochastic automata networks
KW - Kronecker products
KW - Kronecker product properties
KW - preconditioning
ER -