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Showing 2 results for Modarres
Steganalysis Method for LSB Replacement Based on Local Gradient of Image Histogram
M. Mahdavi, Sh. Samavi, N. Zaker, M. Modarres-Hashemi,
Volume 4, Issue 3 (July 2008)
Abstract

In this paper we present a new accurate steganalysis method for the LSB

replacement steganography. The suggested method is based on the changes that occur in the

histogram of an image after the embedding of data. Every pair of neighboring bins of a

histogram are either inter-related or unrelated depending on whether embedding of a bit of

data in the image could affect both bins or not. We show that the overall behavior of all

inter-related bins, when compared with that of the unrelated ones, could give an accurate

measure for the amount of the embedded data. Both analytical analysis and simulation

results show the accuracy of the proposed method. The suggested method has been

implemented and tested for over 2000 samples and compared with the RS Steganalysis

method. Mean and variance of error were 0.0025 and 0.0037 for the suggested method

where these quantities were 0.0070 and 0.0182 for the RS Steganalysis. Using 4800

samples, we showed that the performance of the suggested method is comparable with

those of the RS steganalysis for JPEG filtered images. The new approach is applicable for

the detection of both random and sequential LSB embedding.


Simulation of a Highly Sensitive Piezoresistive Differential Pressure Microsensor
M. Tahmasebipour, M. Modarres,
Volume 14, Issue 4 (December 2018)
Abstract
In this paper, a highly sensitive piezoresistive differential pressure microsensor is proposed. This microsensor is consisted of a silicon microcantilever (Length=145 µm; Width=100 µm; Thickness=0.29 µm) and two piezoresistors were mounted (via proper connections) on the microsensor for measuring the created pressure difference. Applying pressure to the microcantilever induces longitudinal and transverse stresses in the piezoresistors, changing their electric resistance and, consequently, the output voltage in the reading circuit of the microsensor. Longitudinal and transverse stresses, different relative sensor resistances resulting from different pressures, voltage variations along the piezoresistors, and microcantilever deflection resulting from different pressures were investigated. To improve the sensor sensitivity, effect of doping concentration, piezoresistors width, and the width of the structure placed under the piezoresistors were studied. In addition, we studied how increasing the width and length of the beam influenced the sensitivity of the sensor. Based on analysis results, the sensor sensitivity was increased from 0.26 W/Pa to 15.78 W/Pa (~60 times). To evaluate the behavior and performance of the proposed microsensor, the following characteristics were analyzed: maximum microcantilever displacement, von Mises stress distribution along the beam and microsensor resistance variations.

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© 2022 by the authors. Licensee IUST, Tehran, Iran. This is an open access journal distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.