34 research outputs found
Solutions to the GSM Security Weaknesses
Recently, the mobile industry has experienced an extreme increment in number
of its users. The GSM network with the greatest worldwide number of users
succumbs to several security vulnerabilities. Although some of its security
problems are addressed in its upper generations, there are still many operators
using 2G systems. This paper briefly presents the most important security flaws
of the GSM network and its transport channels. It also provides some practical
solutions to improve the security of currently available 2G systems.Comment: 6 Pages, 2 Figure
IMAGE SEPARATION BASED ON NONSUBSAMPLED CONTOURLET(NSCT)
ABSTRACT When an image or a document on a paper acquired through scannin
Multiple description coding of scalable video stream based on unequal loss protection and optimal rate allocation
AbstractForward Error Correction (FEC) codes may be used to protect a video code stream against packet erasures or errors when passing through an error-prone network. To have maximum possible fidelity at the decoder side, an Unequal Loss Protection (ULP) approach should be used to packetize the scalable video code stream, so that the different parts of the scalable video stream are protected according to their importance. Unequal loss-protected packetization leads to segmentation of the scalable code stream, such that the source can be reconstructed with the maximum possible fidelity at the decoder side. In Ardestani et al. (2009) [1] we have found an analytical relation between the optimal sizes of any two consecutive segments. This idea yields an efficient (as efficient as the local search algorithm in Stankovic et al. (2002) [2]) low-complexity progressive solution for the segmentation problem. In this paper, we use a progressive approach for ULP packetization of a scalable video stream generated from a T+2D encoder. In addition, an optimal rate allocation is used for optimal rate budget division between successive Groups Of Pictures (GOPs) of the video sequence. The experimental results demonstrate that the optimal rate budget allocation outperforms the conventional strategy of equal rate budget distribution up to 0.65 dB