An integral formula for the total mean curvature matrix

The notion of total mean curvature matrix of a submanifold in ${\mathbb{R}}^n$ is defined. A kinematic integral formula for the total mean curvature matrix is proved.     

An integral formula on the Heisenberg group

Let $\mathbb{H }^n$ denote the $(2n+1)$ -dimensional (sub-Riemannian) Heisenberg group. In this note, we shall prove an integral identity (see Theorem 1.2) that generalizes a formula obtained in the Seventies by Reilly (Indiana Univ Math J 26(3):459–472, 1977). Some first applications will be given in Sect. 4.     

An asymptotic formula of the Hellinger integral for renewal processes

Asymptotic formulas of the Hellinger integral are used in the investigation of properties of optimal estimates and statistical criteria. For a certain class of renewal processes, this formula was obtained by the author in [Lith. Math. J.,38(2), 131–143 (1998)]. In this paper, we obtain such a formula for all renewal processes whose intermediate renewal moments have absolutely continuous distributions. We use the traditional representation of the Hellinger integral and the theory of large deviations. Šiauliai University, Višinskio 25, 5400 Šiauliai, Lithuania. Translated from Lietuvos Matematikos Rinkinys, Vol. 39, No. 4, pp. 493–497, October–December, 1999. Translated by V. Mackevičius     

Shrinking gradient descent algorithms for total variation regularized image denoising

Total variation regularization introduced by Rudin, Osher, and Fatemi (ROF) is widely used in image denoising problems for its capability to preserve repetitive textures and details of images. Many efforts have been devoted to obtain efficient gradient descent schemes for dual minimization of ROF model, such as Chambolle’s algorithm or gradient projection (GP) algorithm. In this paper, we propose a general gradient descent algorithm with a shrinking factor. Both Chambolle’s and GP algorithm can be regarded as the special cases of the proposed methods with special parameters. Global convergence analysis of the new algorithms with various step lengths and shrinking factors are present. Numerical results demonstrate their competitiveness in computational efficiency and reconstruction quality with some existing classic algorithms on a set of gray scale images.     

An inversion formula for a class of integral transforms,II

In this note we give a procedure for inverting the integral transform f(x) = ∫₀^∞k(xt) φ(t) dt, where the functions f(x) and k(x) are known and φ(x) is to be found. The inversion is accomplished in two steps: by first defining a transforming function, which is an integral, followed by the application of an infinite order differential operator.     

A modified spectral conjugate gradient projection algorithm for total variation image restoration

In this study, a modified spectral conjugate gradient projection method is presented to solve total variation image restoration, which is transferred into the nonlinear constrained optimization with the closed constrained set. The global convergence of the proposed scheme is analyzed. In the end, some numerical results illustrate the efficiency of this method.     

Discrete Dirichlet integral formula

The (discrete) Dirichlet integral is one of the most important quantities in the discrete potential theory and the network theory. In many situations, the dissipation formula which assures that the Dirichlet integral of a function u is expressed as the sum of -u(x)[Δu(x)] seems to play an essential role, where Δu(x) denotes the (discrete) Laplacian of u. This formula can be regarded as a special case of the discrete analogue of Green's Formula. In this paper, we aim to determine the class of functions which satisfy the dissipation formula.     

Alternative derivations for the Poisson integral formula

Poisson integral formula is revisited. The kernel in the Poisson integral formula can be derived in a series form through the direct BEM free of the concept of image point by using the null-field integral equation in conjunction with the degenerate kernels. The degenerate kernels for the closed-form Green's function and the series form of Poisson integral formula are also derived. Two and three-dimensional cases are considered. Also, interior and exterior problems are both solved. Even though the image concept is required, the location of image point can be determined straightforward through the degenerate kernels instead of the method of reciprocal radii.     

First variation formula for generalized gauss graphs

We give a first variation formula in the context of generalized Gauss graphs, a class of generalized surfaces with Gauss maps. Entrata in Redazione il 31 luglio 1998.     

Approximation in variation for Mellin integral operators

We study approximation results for a family of Mellin integral operators in the space of functions of bounded variation in the multidimensional setting, by means of a new concept of variation for multivariate functions. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)