Indirect stability of the wave equation with a dynamic boundary control

In this paper, we consider a damped wave equation with a dynamic boundary control. First, combining a general criteria of Arendt and Batty with Holmgren's theorem we show the strong stability of our system. Next, we show that our system is not uniformly stable in general, since it is the case for the unit disk. Hence, we look for a polynomial decay rate for smooth initial data for our system by applying a frequency domain approach. In a first step, by giving some sufficient conditions on the boundary of our domain and by using the exponential decay of the wave equation with a standard damping, we prove a polynomial decay in of the energy. In a second step, under appropriated conditions on the boundary, called the multiplier control conditions, we establish a polynomial decay in of the energy. Later, we show in a particular case that such a polynomial decay is available even if the previous conditions are not satisfied. For this aim, we consider our system on the unit square of the plane. Using a method based on a Fourier analysis and a specific analysis of the obtained 1‐d problems combining Ingham's inequality and an interpolation method, we establish a polynomial decay in of the energy for sufficiently smooth initial data. Finally, in the case of the unit disk, using the real part of the asymptotic expansion of eigenvalues of the damped system, we prove that the obtained decay is optimal in the domain of the operator.     

Indirect synthesis of multidegree-of-freedom transient systems

It is shown that an indirect synthesis method can be used in the efficient optimal design of multidegree-of-freedon, multidesignelement, nonlinear, transient systems. The technique begins with a limiting performance analysis which requires linear programming for a kinematically linear system, following which the system is selected using system identification methods such that the designed system responds as closely as possible to the limiting performance. The efficiency is a result of the method avoiding the repetitive systems analyses accompanying other numerical optimization methods.This investigation was supported by the NASA Langley Research Center, Grant No. NGR-47-005-145.     

Indirect polarographic determination of stability constants

Polarograms of cadmium at different concentrations of pyridine were taken in 0·5 M potassium nitrate medium. From a plot of the half-wave potentialvs. log (Py), the co-ordination numbers of the complexes were calculated to be one and two. The indirect method was applied to the study of cobalt complexes of pyridine. From the shift in the half-wave potentials of cadmium in the presence of cobalt, a plot of\(\bar n\) vs. pA was obtained which indicated the presence of higher complexes of cobalt and pyridine. The stability constants were calculated.     

求MLE的间接方法

介绍了计算极大似然估计的间接方法.     

Indirect polarographic determination of stability constants

Zinc, complexes of glycollic and lactic acids were studied by an indirect polarographic method using cadmium as the indicator ion. The half-wave potentials of cadmium complexes shift to more positive values in the presence of zinc. From this shift, the formation function, -n, for zinc was obtained as a function of ligand concentration and the stability constants were calculated.     

Indirect polarographic determination of stability constants

The stability constants of cadmium thiosulphate complexes have been determined in 25% methanol medium. The stability constants of thiosulphate complexes of zinc and lanthanum have been determined by the indirect method using cadmium as the indicator ion.     

Indirect assessment of the bivariate survival function

Estimating the bivariate survival function has been a major goal of many researchers. For that purpose many methods and techniques have been published. However, most of these techniques and methods rely heavily on bivariate failure data. There are situations in which failure time data are difficult to obtain and thus there is a growing need to assess the bivariate survival function for such cases. In this paper we propose two techniques for generating families of bivariate processes for describing several variables that can be used to indirectly assess the bivariate survival function. An estimation procedure is provided and a simulation study is conducted to evaluate the performance of our proposed estimator.     

中心条件推导的间接方法

对于一类多项式系统,给出两类对称条件的推导算法,具体讨论了一类三次系统的中心条件;对于Poincare型系统,给出一类等时中心的充分条件．     

Predicting the survival or failure of click-and-mortar corporations: A knowledge discovery approach

With the boom in e-business, several corporations have emerged in the late 1990s that have primarily conducted their business through the Internet and the Web. They have come to be known as the dotcoms or click-and-mortar corporations. The success of these companies has been short lived. This research is an investigation of the burst of the dotcom bubble from a financial perspective. Data from the financial statements of several survived and failed dotcom companies is used to compute financial ratios, which are analyzed using three classification techniques—discriminant analysis, neural networks, and support vector machines to find out whether they can predict the financial fate of companies. Neural networks perform the task better than other techniques. Using discriminant analysis and neural networks, the key financial ratios that play a major role in the process of prediction are identified. Statistical tests are conducted to validate the findings.     

Can Indirect Causation be Real?

Causal realists maintain that the causal relation consists in “something more” than its relata. Specifying this relation in nonreductive terms is however notoriously difficult. Michael Tooley has advanced a plausible account avoiding some of the relation’s most obvious difficulties, particularly where these concern the notion of a cross-temporal “connection.” His account distinguishes discrete from nondiscrete causation, where the latter is suitable to the continuity of cross-temporal causation. I argue, however, that such accounts face conceptual difficulties dating from Zeno’s time. A Bergsonian resolution of these difficulties appears to entail that, for the causal realist, there can be no indirect causal relations of the sort envisioned by Tooley. A consequence of this discussion is that the causal realist must conceive all causal relations as ultimately direct.     

Optimal Direct and Indirect Covering Trees

The maximal covering subtree problem has applications in transportation network design and extensive facility location. A subtree of a network is a tree that is not a full spanning tree. Finding an optimal subtree may involve the two objectives, minimizing the total arc cost or distance of the subtree, and maximizing the subtree's coverage of population or demand at nodes. Coverage may be defined as direct or indirect: indirect coverage requires that a node be within a distance threshold s>0 of the subtree, and direct coverage requires that a node be connected to the subtree (s=0). Previous approaches to this problem have sought to identify optimal subtrees of a parent network that is itself a tree (e.g., a minimum spanning tree). In this paper four new bi-objective zero–one programming models are presented. The first two are models for the problem of finding optimal subtrees on a single spanning tree parent under conditions of (1) direct and (2) indirect coverage. These problems have been addressed previously in the literature. In the third and fourth models, the subtree can be selected from among multiple candidate parent spanning trees simultaneously. The latter models address a new generalization of the first problem and offer both increased flexibility and the potential for a more diverse array of solutions. The models have integer-friendly solution properties and are relatively small in terms of the number of decision variables and constraints. Computational experience is reported for a demonstration problem and results are compared to the results of previous models.     

General theory of domain decomposition: Indirect methods

According to a general theory of domain decomposition methods (DDM), recently proposed by Herrera, DDM may be classified into two broad categories: direct and indirect (or Trefftz‐Herrera methods). This article is devoted to formulate systematically indirect methods and apply them to differential equations in several dimensions. They have interest since they subsume some of the best‐known formulations of domain decomposition methods, such as those based on the application of Steklov‐Poincaré operators. Trefftz‐Herrera approach is based on a special kind of Green's formulas applicable to discontinuous functions, and one of their essential features is the use of weighting functions which yield information, about the sought solution, at the internal boundary of the domain decomposition exclusively. A special class of Sobolev spaces is introduced in which boundary value problems with prescribed jumps at the internal boundary are formulated. Green's formulas applicable in such Sobolev spaces, which contain discontinuous functions, are established and from them the general framework for indirect methods is derived. Guidelines for the construction of the special kind of test functions are then supplied and, as an illustration, the method is applied to elliptic problems in several dimensions. A nonstandard method of collocation is derived in this manner, which possesses significant advantages over more standard procedures. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 296–322, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10008     

A Nonparametric Estimation Problem From Indirect Observations

This paper deals with a nonparametric estimation problem of an integral-type functional from indirect observations where the observation Y (t) is a sum of a known function of an unobservable process X (t) and a Gaussian white noise, and X (t) is a sum of an unknown function a(t) and a Gaussian process. The minimax lower bound on the quality of nonparametric estimation is derived and an asymptotically efficient estimator is proposed. The paper concludes with some examples including one about reduction to parameter estimation.     

关于艾森斯坦因判别法的间接应用

探讨了间接应用艾森斯坦因判别法判断整系数多项式在有理数域上不可约的两种途径.