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Targoviste, Romania

The Valahia University of Târgovişte is a university in Targoviste, Dambovita, Romania. Wikipedia.


Coltuc D.,University Valahia of Targoviste
IEEE Transactions on Information Forensics and Security | Year: 2011

This paper aims at reducing the embedding distortion of prediction error expansion reversible watermarking. Instead of embedding the entire expanded difference into the current pixel, the difference is split between the current pixel and its prediction context. The modification of the context generates an increase of the following prediction errors. Global optimization is obtained by tuning the amount of data embedded into context pixels. Prediction error expansion reversible watermarking schemes based on median edge detector (MED), gradient-adjusted predictor (GAP), and a simplified GAP version, SGAP, are investigated. Improvements are obtained for all the predictors. Notably good results are obtained for SGAP-based schemes. The improved SGAP appears to outperform GAP-based reversible watermarking. © 2011 IEEE. Source


Mortici C.,University Valahia of Targoviste
Computers and Mathematics with Applications | Year: 2011

The aim of this paper is to refine Gurland's formula for approximating pi. We prove the complete monotonicity of a class of functions related to Gurland's formula, and then we state some sharp inequalities. © 2011 Elsevier Ltd. All rights reserved. Source


Mortici C.,University Valahia of Targoviste
Computers and Mathematics with Applications | Year: 2011

The aim of this paper is to improve the Ramanujan formula for approximation the gamma function. A fast asymptotic series is constructed. © 2011 Elsevier Ltd. All rights reserved. Source


Mortici C.,University Valahia of Targoviste
Mathematical and Computer Modelling | Year: 2010

In this paper we solve an open problem posed by Muqattash and Yahdi [I. Muqattash, M. Yahdi, Infinite family of approximations of the digamma function, Math. Comput. Modelling 43 (2006) 1329-1336], also rediscussed by Qi and Guo [F. Qi, B.-N. Guo, Sharp inequalities for the psi function and harmonic numbers, arXiv:0902.2524v1 [math.CA]]. © 2010 Elsevier Ltd. All rights reserved. Source


Mortici C.,University Valahia of Targoviste
Mathematical and Computer Modelling | Year: 2010

The aim of this paper is to establish new, increasingly accurate formulas for evaluating the ratio of gamma functions and the Wallis ratio. © 2010 Elsevier Ltd. All rights reserved. Source

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