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Maulik R.,Meghnad Saha Institute of Technology | Chaki N.,University of Calcutta
2010 International Conference on Computer Information Systems and Industrial Management Applications, CISIM 2010 | Year: 2010

As MANETs use wireless medium for communication, these are vulnerable to many security attacks. In this paper a comprehensive review is done on the very recent state of the art research results on wormhole attacks and relevant mitigation measures. 100% of the works reviewed here are published in last five years, out of which 80% are published in last three years. The simulation results in NS2 helps to quantify the comparative performances of the different solutions proposed. ©2010 IEEE.

Rahaman F.,Jadavpur University | Salucci P.,International School for Advanced Studies | Salucci P.,National Institute of Nuclear Physics, Italy | Kuhfittig P.K.F.,Milwaukee School of Engineering | Rahaman M.,Meghnad Saha Institute of Technology
Annals of Physics | Year: 2014

An earlier study (Rahaman, etal., 2014 and Kuhfittig, 2014) has demonstrated the possible existence of wormholes in the outer regions of the galactic halo, based on the Navarro-Frenk-White (NFW) density profile. This paper uses the Universal Rotation Curve (URC) dark matter model to obtain analogous results for the central parts of the halo. This result is an important compliment to the earlier result, thereby confirming the possible existence of wormholes in most of the spiral galaxies. © 2014 Elsevier Inc.

Sarkar A.,Kalyani Government Engg College | De S.,Meghnad Saha Institute of Technology | Dey A.,Kalyani Government Engg College | Sarkar C.K.,Jadavpur University
Journal of Computational Electronics | Year: 2012

We report a systematic, quantitative investigation of analog and RF performance of cylindrical surroundinggate (SRG) silicon MOSFET. To derive the model, a pseudotwo- dimensional (2-D) approach applying Gauss's law in the channel region is extended for the cylindrical SRG MOSFET. Based on surface potential approach, expressions of drain current and differential capacitances are obtained analytically. Analog/RF figures of merit of SRG MOSFET are studied, including transconductance efficiency g m/I d, intrinsic gain, output resistance, cutoff frequency f T, maximum oscillation frequency f max and gain bandwidth product GBW. The trends related to their variations along the downscaling of dimension are provided. In order to validate our model, the modeled predictions have been extensively compared with the simulated characteristics obtained from the ATLAS device simulator and a nice agreement is observed with a wide range of geometrical parameters. © Springer Science+Business Media LLC 2012.

Sarkar A.,Kalyani Goverenment Engineering College | Kumar Das A.,Kalyani Goverenment Engineering College | De S.,Meghnad Saha Institute of Technology | Kumar Sarkar C.,Jadavpur University
Microelectronics Journal | Year: 2012

This work uncovers the potential benefit of fully-depleted short-channel triple-material double-gate (TM-DG) SOI MOSFET in the context of RF and analog performance characteristics. A systematic, quantitative investigation of the analog and RF performance figures-of-merits (FOMs) of TM-DG MOSFET are presented. The key idea in this paper is to demonstrate the improved RF, analog and linearity performance exhibited by TM-DG MOSFET over dual-material dual-gate (DM-DG) and conventional single-material double-gate (SM-DG) MOSFET. Using two-dimensional (2-D) device simulations, we have examined various design issues and provided the reasons for the improved performance. The effect of different length ratios of three channel regions related to three different gate materials of TM-DG structure on the RF and analog performance have also been discussed. Simulations reveal an improvement of intrinsic gain by 20.41% and 38.53%, an increase of 14.23% and 26.4% in the case of f T, an increase of 13.9% and 23.85% in the case of f max values for TM-DG (1:2:3) MOSFET compared to DM-DG and SM-DG MOSFET respectively. As a result, we demonstrate that TM-DG MOSFET can be a viable option to enhance the performance of SOI technology for high-frequency analog applications. © 2012 Elsevier Ltd.

Das D.,Meghnad Saha Institute of Technology | Maitra A.,University of Calcutta
International Journal of Satellite Communications and Networking | Year: 2012

A channel model is proposed to predict the time series of Ku band rain attenuation during a rain event at a tropical location. The model is based on considering the Gaussian distribution of the conditional occurrence of rain attenuation with a particular value of the attenuation occurring before. The mean (μ) and standard deviation (σ) for the distribution are modeled with the experimental data. The measured attenuation at a particular time instant is used to obtain μ and σ and to predict the attenuation after certain interval. The channel model has tested well giving the predicted attenuation that agrees with the measured value with a mean error within 15% higher than 1 dB. Validity of the model is also tested with the first-order and second-order statistics of attenuation occurrence, on a long-term basis. The method can also be applied even if attenuation measurements are missing for certain period of time with increased error. © 2011 John Wiley & Sons, Ltd.

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