One of the main methods of examining non-normal operators, acting on Hilbert spaces, is the theory of contractions. This area of operator theory was developed by Béla Sz.-Nagy and Ciprian Foias from the dilation theorem of Sz.-Nagy. Sz.-Nagy and Foias classi ed the contractions according to their asymptotic behaviour. They got strong structural results in the case when the contraction and its a...

Let X be a Banach space. Let K be a nonempty subset of X. Let T : K → K be an I-asymptotically quasi-nonexpansive type mapping and I : K → K be an asymptotically quasi-nonexpansive type mappings in the Banach space. Our aim is to establish the necessary and sufficient conditions for the convergence of the Ishikawa iterative sequences with errors of an I-asymptotically quasi-nonexpansive type ma...

In this paper, some fixed point theorems for nonexpansive mappings in partially ordered spherically complete ultrametric spaces are proved. In addition, we investigate the existence of fixed points for nonexpansive mappings in partially ordered non-Archimedean normed spaces. Finally, we give some examples to discuss the assumptions and support our results.

We study the constraints imposed by the requirement of Asymptotic Safety on a class of inflationary models with an inflaton field non-minimally coupled to the Ricci scalar. The critical surface in the space of theories is determined by the improved renormalization group flow which takes into account quantum corrections beyond the one loop approximation. The combination of constraints deriving f...

In this paper we discuss estimation of parameters from quantized data. Extending some recent results appeared in the literature we show that, under a regularity assumption on the parametric model describing the data, the Maximum Likelihood estimator can be found, asymptotically, in closed form in two steps. The first is a non-linear (and invertible) mapping of the observed relative frequencies ...

The present study measured phoneme recognition as a function of signal-to-noise level under conditions of spectral smearing and nonlinear amplitude mapping. Speech sounds were divided into 16 analysis bands. The envelope was extracted from each band by half-wave rectification and low-pass filtering and was then distorted by a power-law transformation whose exponents varied from a strongly compr...

OBJECTIVES The aim of this study is to assess the influence of the shape of the acoustic-to-electric mapping function on speech recognition in noise by cochlear implant listeners. DESIGN A new acoustic-to-electric mapping function is proposed for cochlear implant users in noisy environments. The proposed s-shaped mapping function was expansive for low input levels up to a knee point level and...