For any prime power q and any dimension s≥1, a new construction of (t, s)-sequences in base q using global function fields is presented. The construction yields an analog of Halton sequences for global function field...
详细信息
For any prime power q and any dimension s≥1, a new construction of (t, s)-sequences in base q using global function fields is presented. The construction yields an analog of Halton sequences for global function fields. It is the first general construction of (t, s)-sequences that is not directly based on the digital method. The construction can also be put into the framework of the theory of (u, e, s)-sequences that was recently introduced by Tezuka and leads in this way to better discrepancy bounds for the constructed sequences.
The design of the sliding hyperplanes of a variable structure control system is an important part of the controller design process, and will be considered in this paper. The method outlined here results in the eigenva...
The design of the sliding hyperplanes of a variable structure control system is an important part of the controller design process, and will be considered in this paper. The method outlined here results in the eigenvalues of the closed-loop system during sliding lying in a specified sector in the left-hand half-plane. Numerical examples are given, and the effect of an arbitrary positive definite matrix in a complex Riccati equation on the positioning of the eigenvalues within the sector, is investigated.
A localized Fourier collocation method is proposed for solving certain types of elliptic boundary value *** method first discretizes the entire domain into a set of overlapping small subdomains,and then in each of the...
详细信息
A localized Fourier collocation method is proposed for solving certain types of elliptic boundary value *** method first discretizes the entire domain into a set of overlapping small subdomains,and then in each of the subdomains,the unknown functions and their derivatives are approximated using the pseudo-spectral Fourier collocation *** key idea of the present method is to combine the merits of the quick convergence of the pseudo-spectral method and the high sparsity of the localized discretization technique to yield a new framework that may be suitable for large-scale *** present method can be viewed as a competitive alternative for solving numerically large-scale boundary value problems with complex-shape *** numerical experiments involving Poisson,Helmholtz,and modified-Helmholtz equations in both two and three dimensions are presented to demonstrate the accuracy and efficiency of the proposed method.
The optimal tracking problem of the probability density function of a stochastic process can be expressed in terms of an optimal bilinear control problem for the Fokker-Planck equation, with the control in the coeffic...
详细信息
The stabilization of uncertain systems governed by an evolution equation in a real Hilbert space is studied. The uncertain systems under consideration are described by state equations in which both the state and input...
The stabilization of uncertain systems governed by an evolution equation in a real Hilbert space is studied. The uncertain systems under consideration are described by state equations in which both the state and input operators depend upon uncertain parameters. Exponential stability is achieved by the suitable choice of state feedback control. The proofs are based upon perturbation analysis of semigroup and Lyapunov theory. A number of examples are given to illustrate the approach.
A fully time dependent mathematical model of the thermal plasma at L = 1.4 is described. In the mathematical model account is taken of a quiet-time E × B drift in the meridional plane. Atmospheric conditions appr...
A fully time dependent mathematical model of the thermal plasma at L = 1.4 is described. In the mathematical model account is taken of a quiet-time E × B drift in the meridional plane. Atmospheric conditions appropriate to equinox at sunspot minimum and at sunspot maximum are considered. Results of the model calculations are presented. Emphasis is placed on the effects on the thermal plasma of a quiet-time E × B drift in the meridional plane. A comparison of the model calculations which include an E × B drift with those in which there is no E × B drift shows than an E × B drift significantly affects the plasma concentration and temperature distributions during the day at both sunspot minimum and sunspot maximum; the effects at night are very small. An upward E × B drift during the day increases both NmF2 and hmF2 and decreases the plasma temperature. The decrease in plasma temperature is due primarily to the increase in plasma concentration. It is more pronounced in the electron temperature than in the ion temperature and it varies considerably with altitude, time and atmospheric conditions. The changes in plasma concentration and temperature brought about by an E × B drift also change the O + -H + transition height and the O + and H + tube contents. For the E × B drifts considered the O + -H + transition height is raised during the morning and lowered during the afternoon. The changes in O + tube content roughly follow the changes in NmF2. The changes in H + tube content, however, are small since the H + tube content is controlled by the H + concentration at the higher altitudes of the tube of plasma and these concentration values are only slightly affected by the E × B drifts considered.
In this paper, a new discrete formulation and a type of new posteriori error estimators for the second-order element discretization for Stokes problems are presented, where pressure is approximated with piecewise fir...
详细信息
In this paper, a new discrete formulation and a type of new posteriori error estimators for the second-order element discretization for Stokes problems are presented, where pressure is approximated with piecewise first-degree polynomials and velocity vector field with piecewise second-degree polynomials with a cubic bubble function to be added. The estimators are the globally upper and locally lower bounds for the error of the finite element discretization. It is shown that the bubble part for this second-order element approximation is substituted for the other parts of the approximate solution.
The single ionization rate of the diatomic molecular ion H2^＋ with different active orbitals in an intense field is studied by using S-matrix theory. Our results show that the orientation-dependent single ionization ...
详细信息
The single ionization rate of the diatomic molecular ion H2^＋ with different active orbitals in an intense field is studied by using S-matrix theory. Our results show that the orientation-dependent single ionization probability of H2^＋ is greatly dependent on the symmetry and the electron density distribution of its initial states, and it can be used to identify the excited state of the molecular ion in the dissociation process.
Robertson and Seymour prove that a set of graphs of bounded tree-width is well-quasi-ordered by the graph minor relation. By extending their methods to matroids, Geelen, Gerards, and Whittle prove that a set of matroi...
详细信息
As part of work to connect phylogenetics with machine learning, there has been considerable recent interest in vector encodings of phylogenetic trees. We present a simple new "ordered leaf attachment" (OLA) ...
详细信息
暂无评论