Visual Cryptography and Steganography Methods - Review

In today’s information era information hiding becomes very much important as people transmits the information as innocent as credit card to online stores and as dangerous as terrorist plot to hijackers. The art of information hiding receive attention of the researchers. This paper provides a review of two methods – Visual Cryptography and Steganography for secure communication via a common communication channel. DOI: 10.17762/ijritcc2321-8169.16043

Excitonic Effects in Quantum Wires

We review the effects of Coulomb correlation on the linear and non-linear optical properties of semiconductor quantum wires, with emphasis on recent results for the bound excitonic states. Our theoretical approach is based on generalized semiconductor Bloch equations, and allows full three-dimensional multisubband description of electron-hole correlation for arbitrary confinement profiles. In particular, we consider V- and T-shaped structures for which significant experimental advances were obtained recently. Above band gap, a very general result obtained by this approach is that electron-hole Coulomb correlation removes the inverse-square-root single-particle singularity in the optical spectra at band edge, in agreement with previous reports from purely one-dimensional models. Strong correlation effects on transitions in the continuum are found to persist also at high densities of photoexcited carriers. Below bandgap, we find that the same potential- (Coulomb) to kinetic-energy ratio holds for quite different wire cross sections and compositions. As a consequence, we identify a shape- and barrier-independent parameter that governs a universal scaling law for exciton binding energy with size. Previous indications that the shape of the wire cross-section may have important effects on exciton binding are discussed in the light of the present results.Comment: Proc. OECS-5 Conference, G\"ottingen, 1997 (To appear in Phys. Stat. Sol. (b)

Foreland segmentation along an active convergent margin: New constraints in southeastern Sicily (Italy) from seismic and geodetic observations

We performed an in-depth analysis of the ongoing tectonics of a large sector of southern Sicily, including the Hyblean Foreland and the front of the Maghrebian Chain, as well as the Ionian Sea offshore, through the integration of seismic and GPS observations collected in the nearly two decades. In particular, a dataset consisting of more than 1100 small-to moderate-magnitude earthquakes (1.0 <= M-L <= 4.6) has been used for local earthquake tomography in order to trace the characteristics of the faulting systems, and for focal mechanisms computation to resolve the current local stress field and to characterise the faulting regime of the investigated area. In addition, GPS measurements, carried out on both episodic and continuous stations, allowed us to infer the main features of the current crustal deformation pattern. Main results evidence that the Hyblean Plateau is subject to a general strike-slip faulting regime, with a maximum horizontal stress axis NW-SE to NNW-SSE oriented, in agreement with the Eurasia-Nubia direction of convergence. The Plateau is separated into two different tectonic crustal blocks by the left-lateral strike-slip Scicli-Ragusa Fault System. The western block moves in agreement with central Sicily while the eastern one accommodates part of the contraction arising from the main Eurasia-Nubia convergence. Furthermore, we provided evidences leading to consider the Hyblean-Maltese Escarpment Fault System as an active boundary characterised by a left-lateral strike-slip motion, separating the eastern block of the Plateau from the Ionian basin. All these evidences lend credit to a crustal segmentation of the southeastern Sicily. (C) 2014 Elsevier B.V. All rights reserved

Invited response on: dual-plane retro-pectoral versus pre-pectoral dti breast reconstruction. An italian multicenter experience

Invited Response on: Dual-Plane Retro-Pectoral Versus Pre-pectoral DTI Breast Reconstruction: An Italian Multicenter Experienc

Sharp-line electroluminescence from individual quantum dots by resonant tunneling injection of carriers

We report sharp electroluminescence lines from individual self-assembled InAs quantum dots (QDs) excited by resonant tunneling injection of carriers from the n- and p-doped GaAs layers of a p-i-n diode. Bias-tunable tunneling of carriers into the dots provides a means of controlling injection and light emission from a small number of individual dots within a large ensemble. We also show that the extent of carrier energy relaxation prior to recombination can be controlled by tailoring the morphology of the QD layer. © 2006 American Institute of Physics

Adversarial robustness guarantees for classification with Gaussian Processes

We investigate adversarial robustness of Gaussian Process classification (GPC) models. Specifically, given a compact subset of the input space T⊆ℝd enclosing a test point x∗ and a GPC trained on a dataset , we aim to compute the minimum and the maximum classification probability for the GPC over all the points in T.In order to do so, we show how functions lower- and upper-bounding the GPC output in T can be derived, and implement those in a branch and bound optimisation algorithm. For any error threshold ϵ>0 selected \emph{a priori}, we show that our algorithm is guaranteed to reach values ϵ-close to the actual values in finitely many iterations.We apply our method to investigate the robustness of GPC models on a 2D synthetic dataset, the SPAM dataset and a subset of the MNIST dataset, providing comparisons of different GPC training techniques, and show how our method can be used for interpretability analysis. Our empirical analysis suggests that GPC robustness increases with more accurate posterior estimation