Some aspects of goal-oriented a posteriori error estimation are addressed in the context of steady convection-diffusion equations. The difference between the exact and approximate values of a linear target functional is expressed in terms of integrals that depend on the solutions to the primal and dual problems. Gradient averaging techniques are employed to separate the element residual and dif...

∗ Corresponding author. Tel: 86-731-58293939. Supported by a grant from Hunan Education Bureau(09C963). Abstract—Multifilter banks having all properties of symmetry, balancing, optimum time-frequency resolution, arbitrary order vanishing moment, orthogonality and compactly supported together are constructed for the first time. Thus overcome the shortcoming of the present orthogonal optimum time...

Approximate joint diagonalization of a set of matrices is an essential tool in many blind source separation (BSS) algorithms. A common measure of the attained diagonalization of the set is the weighted least-squares (WLS) criterion. However, most well-known algorithms are restricted to finding an orthogonal diagonalizing matrix, relying on a whitening phase for the nonorthogonal factor. Often, ...

Natural frequencies of a clamped axially loaded beam carrying an eccentric end rigid body are computed. A linearly varying non-follower axial force representing the beam’s own weight is taken into consideration. An analytical form of the frequency equation of the structure is obtained and solved numerically. The parameters associated with the end rigid body, the mass, the rotary inertia and the...

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Let A and B be rectangular matrices. Then A is orthogonal to B if II A + f-LB II ?: II A II for every scalar f-L. Some approximation theory and convexity results on matrices are used to study orthogonality of matrices and answer an open problem of Bhatia and Semrl. © 2002 Elsevier Science Inc. All rights reserved.

The class of shape equivalences for a pair (C,K) of categories is the orthogonal of K, that is Σ = K. Then Σ is internally saturated (Σ = Σ). On the other hand, every internally saturated class of morphisms Σ ⊂ Mor(C), is the class of shape equivalences for some pair (C,K). Moreover, every class of shape equivalences Σ enjoys a calculus of left fractions and such a fact allows one to use techni...

Adámek and Sousa recently solved the problem of characterizing the subcategories K of a locally λ-presentable category C which are λ-orthogonal in C, using their concept of Kλ-pure morphism. We strenghten the latter definition, in order to obtain a characterization of the classes defined by orthogonality with respect to λ-presentable morphisms (where f :A B is called λ-presentable if it is a λ-...

The characterization of automorphisms of Bernstein algebras is an open problem. We only know some particular results. Previously we have characterized the automorphisms of quasiorthogonal, orthogonal, and strongly orthogonal weak Bernstein-Jordan algebras. In this paper we work on the minimal dimension with respect to quasiorthogonality, orthogonality, and strong orthogonality. We establish som...