共查询到20条相似文献,搜索用时 31 毫秒
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** Email: cli{at}zju.edu.cn*** Email: wjh{at}zjut.edu.cn The -conditions for vector fields on Riemannian manifolds areintroduced. The -theory and the -theory for Newton's methodon Riemannian manifolds are established under the -conditions.Applications to analytic vector fields are provided and theresults due to Dedieu et al. (2003, IMA J. Numer. Anal., 23,395419) are improved. 相似文献
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Han J. D.; Jiang Z.; Nie Y. Y. 《IMA Journal of Mathematical Control and Information》2007,24(4):473-482
Email: jdhan{at}sia.cn Email: zhjiang{at}sia.cn Corresponding author Email: nyy{at}sia.cn
Received on March 6, 2006; Accepted on September 4, 2006 In this paper, the conception of numerical stabilization, whichis related to mantissa digits of computer and dimensions ofsystem, is described; and several strategies for the numericalstabilization of polynomial and matrix are presented. 相似文献
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Implicit algorithms and their linearization for the transient incompressible Navier-Stokes equations
Email: na.asmith2{at}na-net.ornl.gov Email: na.silvester{at}na-net.ornl.gov The issue of appropriate time discretization methods for theunsteady incompressible Navier-Stokes equations is consideredfrom a practical perspective. Conventional implicit time-steppingalgorithms are not feasible for long-time simulations sincethey inherit the quadratic nonlinearity of the steady-stateequations. As a result, two new linearized versions of the purealgorithms are analyzed herein. These have similar stabilityproperties and comparable accuracy to the underlying nonlinearmethods. 相似文献
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ALTMANN DORIS; ALTMANN KLAUS 《IMA Journal of Mathematical Control and Information》2000,17(2):137-146
Email: altmannd{at}rki.deEmail: altmann{at}mathematik.hu-berlin.de The approach of N Gay for estimating the coverage of a multivalentvaccine from antibody prevalence data in certain age cohortsis complemented by using computer aided elimination theory ofvariables. Hereby, Gay's usage of numerical approximation canbe replaced by exact formulae which are surprisingly nice, too. 相似文献
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Email: g.moore{at}ma.ic.ac.uk or na.gmoore New algorithms for the computation of periodic and connectingorbits of autonomous differential equations are developed. Previousmethods have parametrized these curves by the independent timevariable, but our procedure is based on the canonical arclengthparametrization. 相似文献
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In this paper we analyze the use of a combined Nystrm and finite-elementprocedure for approximating the scattered time-harmonic acousticfield produced when an incident wave interacts with a boundedinhomogeneity. The coupling technique uses a smooth artificialboundary and explicitly decouples the integral equation andfinite-element computations. We prove convergence of the method.One highlight of this analysis is that we prove Sobolev spaceerror estimates for the Nystrm scheme (which is usually analyzedin Hlder spaces). We also present some numerical results.
E-mail: kirsch{at}am.uni-erlangen.de
E-mail: monk{at}math.udel.edu 相似文献
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Multiple criteria models for evaluation of competitive bids 总被引:1,自引:0,他引:1
Email: slliu{at}mail.east.net.cnAuthor for correspondence Email: mskklai{at}cityu.edu.hkEmail: sywang{at}iss02.iss.ac.cn In this paper, two general bidding systems are proposed to aidan owner to select one contractor based on multiple-attributedecision making models. They are named the general multiple-attributelower-bidder system and the general multiple-attribute average-bid system and are an extension (and refreshment) of the multiparameterbidding system and the average-bid method, respectively. Thepreference of the owner over the criteria (or attributes) relevantto construction work award is incorporated into the two newsystems if necessary and required by the owner. The values ofthe attributes (excluding the cost) required to be determinedby the owner in the multiparameter bidding system are not necessarilydetermined in the general multiple-attribute lower-bidder system.This reduces the burden to the owner. The two new bidding systemsare demonstrated via an example, and are compared with the multiparameterbidding system and the average-bid method. The comparisons showthat the preference of the owner in regard to the attributesrelevant to selection of contractors has a significant effecton bid evaluation. The two new systems preserve the form ofthe competitive bidding concept and can easily be applied topractice. 相似文献
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** Email: braess{at}num.rub.de*** Email: wh{at}mis.mpg.de Approximations of 1/x by sums of exponentials are well studiedfor finite intervals. Here the error decreases like (exp(ck))with the order k of the exponential sum. In this paper we investigateapproximations of 1/x in the interval [1, ). We prove estimatesof the error by and confirm this asymptotic estimate by numerical results. Numericalresults lead to the conjecture that the constant in the exponentequals . 相似文献
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Error estimates for the finite-element solution of an elliptic singularly perturbed problem 总被引:3,自引:0,他引:3
e-mail:ang{at}am.uni-erlangen.de The paper deals with an upwind discretization of finite-volume-typefor singularly perturbed elliptic boundary value problems. Stability,inverse monotonicity and convergence are considered. The mainobjective is to pursue the dependence of the error estimateon the perturbation parameter. 相似文献
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Email: skrakowi{at}usk.pk.edu.pl
Received on June 15, 2005; Accepted on July 12, 2006 In this paper, the time-optimal control problem for parabolicsystems in which time lags appear in the integral form bothin the state equation and in the Neumann boundary conditionis presented. The particular properties of the optimal controlare discussed. 相似文献
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In a recent paper, Fischer and Finn have proposed a procedureto improve the accuracy in the measurement of capillary contactangles, based on the use of vessels with canonical cross-sections.We simulate numerically the behaviour of such shapes for a numberof cross-sections and fluid contact angles. Our approximationconsists of the minimization of a suitable convex functionaldiscretized by finite elements.
e-mail: bellettini{at}sns.it
e-mail: paolini{at}isa.mat.unimi.it 相似文献
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Explicit and semi-implicit finite-difference schemes approximatingnon-homogeneous scalar conservation laws are analyzed. Optimalerror bounds independent of the stiffness of the underlyingequation are presented.
This author has been supported by The Norwegian Research Council(NFR), program No 100284/431. e-mail: schroll{at}igpm.rwth-aachen.de
This author has been supported by The Norwegian Research Council(NFR), program Nos 100284/431 and STP.29643. e-mail: ragnar{at}ifi.uio.no 相似文献
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An LMI-based approach for robust stabilization of time delay systems containing saturating actuators
El Haoussi Fatima; Tissir El Houssaine 《IMA Journal of Mathematical Control and Information》2007,24(3):347-356
Email: elhaous_fati{at}yahoo.fr Corresponding author. Email: elh_tissir{at}yahoo.fr
Received on September 8, 2005; Accepted on July 24, 2006 This paper deals with the problem of robust stabilization foruncertain systems with input saturation and time delay in thestate. The parameter uncertainties are time-varying and unknownbut are norm bounded. Sufficient conditions obtained via a linearmatrix inequality formulation are stated to guarantee the localstabilization. The method of synthesis consists in determiningsimultaneously a state feedback control law and an associateddomain of safe admissible states for which the stability ofthe closed-loop system is guaranteed when control saturationseffectively occur. Numerical examples are used to demonstratethe effectiveness of the proposed design technique. 相似文献
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BOLDRINI JOSE L.; COSTA MICHEL I. S. 《IMA Journal of Mathematical Control and Information》2000,17(1):33-51
Email: boldrini{at}ime.unicamp.brAuthor to whom correspondence should be addressed. Email: michel{at}Incc.br Three nonlinear models of tumour cell growth under continuousdelivery of cycle nonspecific anticancer agents are studied.A dynamical optimization problem with the objective of minimizingthe final level of tumour cells is posed for these mathematicalsetups. The simplest setup does not possess toxicity constraints,whereas the other setups contain a dynamical equation describingthe therapy burden as a toxicity criterion. In addition, thethird setting contains the dynamics of drug resistant cells.A discussion conceming the optimal strategies of the respectivemodels is performed. 相似文献
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Email: chlien{at}mail.nkmu.edu.tw
Received on August 10, 2006; Accepted on September 6, 2006 In this paper, delay-dependent guaranteed cost observer-basedcontrol for neutral systems with time-varying delays is considered.Control and observer gains will be given from the linear matrixinequality feasible solutions. Optimal guaranteed cost observer-basedcontrol which will minimize the guaranteed cost of the systemis provided. 相似文献
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Wu Ligang; Lam James; Wang Changhong 《IMA Journal of Mathematical Control and Information》2009,26(1):23-44
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Received on 7 September 1993. Revised on 20 February 1996. In this paper we develop and test a simple automatic algorithmfor constructing curvature- and torsion-continuous interpolantsin R3 which are shape-preserving in a sense that takes intoaccount the convexity, torsion, coplanarity and collinearityinformation contained in the polygonal line connecting the interpolationpoints. This algorithm exploits the asymptotic properties ofa family of C2 polynomial splines of non-uniform degree, whichtend to the above-mentioned polygonal line, as the segment degreestend to infinity. The performance of the algorithm is testedfor a three-dimensional data set, containing coplanar and collineargroups of points as well.
E-mail address: kaklis{at}deslab.ntua.gr Tel.: +30-1-7721419Telefax: +30-1-7721408
E-mail address: menelaos{at}sccm.stanford.edu 相似文献
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Algorithms for the computation of the pseudospectral radius and the numerical radius of a matrix 总被引:1,自引:0,他引:1
** Email: mengi{at}cs.nyu.edu*** Email: overton{at}cs.nyu.edu Two useful measures of the robust stability of the discrete-timedynamical system xk+1 = Axk are the -pseudospectral radius andthe numerical radius of A. The -pseudospectral radius of A isthe largest of the moduli of the points in the -pseudospectrumof A, while the numerical radius is the largest of the moduliof the points in the field of values. We present globally convergentalgorithms for computing the -pseudospectral radius and thenumerical radius. For the former algorithm, we discuss conditionsunder which it is quadratically convergent and provide a detailedaccuracy analysis giving conditions under which the algorithmis backward stable. The algorithms are inspired by methods ofByers, BoydBalakrishnan, HeWatson and BurkeLewisOvertonfor related problems and depend on computing eigenvalues ofsymplectic pencils and Hamiltonian matrices. 相似文献