Sharif Digital Repository

Steganalysis of least significant bit (LSB) embedded images in spatial domain has been investigated extensively over the past decade and most well-known LSB steganography methods have been shown to be detectable. However, according to the latest findings in the area, two major issues of very low-rate (VLR) embedding and content-adaptive steganography have remained hard to resolve. The problem of VLR embedding is indeed a generic problem to any steganalyser, while the issue of adaptive embedding specifically depends on the hiding algorithm employed. The latter challenge has recently been brought up again to the area of LSB steganalysis by highly undetectable stego image steganography that... 

Molecular dynamics simulations are carried out to investigate the manipulation of metallic clusters on double-layer surfaces. The system parts are made of transition metals. The conditions which are subjected to change in the tests are material combinations for cluster, main substrate and lubricant layer (adlayer). In addition to qualitative observations, two criteria which represent the particle deformation and substrate abrasion are utilized as evaluation tools and are computed for each case. Obtaining this sort of knowledge is highly beneficial for further experiments in order to be able to plan the conditions and routines, which guarantee better success in the manipulation process  

This paper addresses the fabrication of bronze-nano-graphite coatings containing 30. nm sized graphite particles. Addition of Poly Vinyl Pyrrolidone (PVP) and dispersing the suspension by ultrasound was utilized to stabilize the electroplating solution. Pulsed current electrodeposition was used and the deposits were characterized in terms of graphite content, particle dispersion in coating and morphology. The wear behavior of the coating was compared to bronze-micro-graphite coatings prepared with the same experimental conditions. The present coating showed improved wear resistance in comparison to bronze-micro-graphite coatings at the same graphite content  

Asymmetric sheet rolling is simulated by using an elastic-plastic arbitrary Lagrangian-Eulerian (ALE) finite element method. The ALE finite element approach easily predicts the curvature development due to inequality in work roll/plate surface finish (interface friction) and speed mismatch. An isotropic work hardening material is assumed. Reasonable agreements were found between the numerical method and the experimental results. © 2006 Elsevier B.V. All rights reserved  

Multi-dimensional spatial analysis of image pixels have not been much investigated for the steganalysis of the LSB Steganographic methods. Pixel distribution based steganalysis methods could be thwarted by intelligently compensating statistical characteristics of image pixels, as reported in several papers. Simple LSB replacement methods have been improved by introducing smarter LSB embedding approaches, e.g. LSB matching and LSB+ methods, but they are basically the same in the sense of the LSB alteration. A new analytical method to detect LSB stego images is proposed in this paper. Our approach is based on the relative locations of image pixels that are essentially changed in an LSB... 

Locally multipath adaptive routing (LMAR) protocol, classified as a new reactive distance vector routing protocol for MANETs is proposed in this paper. LMAR can find an ad-hoc path without selfish nodes and wormholes using a random search algorithm in polynomial-time. Also when the primary path fails, it discovers an alternative safe path if network graph remains connected after eliminating selfish/malicious nodes. The main feature of LMAR to seek safe route free of selfish and malicious nodes in polynomial time is its searching algorithm and flooding stage that its generated traffic is equiloaded compared to single-path routing protocols but its ability to bypass the attacks is much better... 

Based on the fact that the manipulation of fine nanoclusters calls for more precise modelling, the aim of this paper is to conduct an atomistic investigation for interaction analysis of particle-substrate system for pushing and positioning purposes. In the present research, 2D molecular dynamics simulations have been used to investigate such behaviours. Performing the planar simulations can provide a fairly acceptable qualitative tool for our purpose while the computation time is reduced extremely in comparison to 3D simulations. To perform this study, Nose-Hoover dynamics and Sutton-Chen interatomic potential will be used to investigate the behaviour of the aforementioned system. Pushing of... 

Molecular dynamics simulations are carried out to investigate the manipulation of metallic clusters on stepped surfaces. Five surface forms are considered in the simulations. The system parts are made of pure transition metals and Sutton-Chen many-body potential is used as interatomic potential. The conditions which are subjected to change in the tests include: materials used for particles and substrate, and surface step conditions. In addition to qualitative observations, two criteria which represent the particle deformation and substrate abrasion are utilized as evaluation tools and are computed for each case. Simulation results show the effect of the aforementioned working conditions on...