Interleaved reception method for restored vector quantization image

The transmission of image compression by vector quantization produce wrong blocks in received image which are completely different to the original one that makes the restoration process too hard because we don’t have any information about the original blocks. As a solution of this problem we try to keep the maximum of pixels that form the original block by building new blocks. Our proposition is based on decomposition and interleaving. For the simulation we use a binary symmetric channel with different BER and in the restoration process we use simple median filter just to check the efficiency of proposed approach

Data analysis for image transmitted using Discrete Wavelet Transform and Vector Quantization compression

In this paper we are going to study the effect of channel noise in image compressed with vector quantization and discrete wavelet transform. The objective of this study is to analyze and understand the way that the noise attack transmitted data by doing lot of tests like dividing the indices in different levels according to discrete wavelet transform and dividing  each level in frames of bits. The collected information well helps us to propose solutions to make the received image more resistible to the channel noise also to benefit from the good representation obtained by using vector quantization and discrete wavelet transform

The Noise Reduction over Wireless Channel Using Vector Quantization Compression and Filtering

The transmission of compressed data over wireless channel conditions represents a big challenge. The idea of providing robust transmission gets a lot of attention in field of research. In this paper we study the effect of the noise over wireless channel. We use the model of Gilbert-Elliot to represent the channel. The parameters of the model are selected to represent three cases of channel. As data for transmission we use images in gray level size 512x512. To minimize bandwidth usage we compressed the image with vector quantization also in this compression technique we study the effect of the codebook in the robustness of transmission so we use different algorithms to generate the codebook for the vector quantization finally we study the restoration efficiency of received image using filtering and indices recovery technique

Double domination critical and stable graphs upon vertex removal

In a graph a vertex is said to dominate itself and all its neighbors. A double dominating set of a graph G is a subset of vertices that dominates every vertex of G at least twice. The double domination number of G, denoted $γ_{×2}(G)$, is the minimum cardinality among all double dominating sets of G. We consider the effects of vertex removal on the double domination number of a graph. A graph G is $γ_{×2}$-vertex critical graph ($γ_{×2}$-vertex stable graph, respectively) if the removal of any vertex different from a support vertex decreases (does not change, respectively) $γ_{×2}$(G). In this paper we investigate various properties of these graphs. Moreover, we characterize $γ_{×2}$-vertex critical trees and $γ_{×2}$-vertex stable trees

Double domination edge removal critical graphs

International audienc

Image Vector Quantization codec indexes filtering

Vector Quantisation (VQ) is an efficient coding algorithm that has been widely used in the field of video and image coding, due to its fast decoding efficiency. However, the indexes of VQ are sometimes lost because of signal interference during the transmission. In this paper, we propose an efficient estimation method to conceal and recover the lost indexes on the decoder side, to avoid re-transmitting the whole image again. If the image or video has the limitation of a period of validity, re-transmitting the data wastes the resources of time and network bandwidth. Therefore, using the originally received correct data to estimate and recover the lost data is efficient in time-constrained situations, such as network conferencing or mobile transmissions. In nature images, the pixels are correlated with their neighbours and VQ partitions the image into sub-blocks and quantises them to the indexes that are transmitted; the correlation between adjacent indexes is very strong. There are two parts of the proposed method. The first is pre-processing and the second is an estimation process. In pre-processing, we modify the order of codevectors in the VQ codebook to increase the correlation among the neighbouring vectors. We then use a special filtering method in the estimation process. Using conventional VQ to compress the Lena image and transmit it without any loss of index can achieve a PSNR of 30.429 dB on the decoder. The simulation results demonstrate that our method can estimate the indexes to achieve PSNR values of 29.084 and 28.327 dB when the loss rate is 0.5% and 1%, respectively

E-révolutions et révolutions

Ce que l'on a pris l’habitude d’appeler les « Printemps arabes » draine son lot de mythes et de fantasmes, et nombre de textes se contentent d’appréhender la surface des mouvements avec un regard mêlant fascination et exaltation pour les réseaux sociaux. Or, les reflets numériques de l’expression contestataire ne suffisent pas à expliquer le phénomène. Il faut préférer la connaissance des causes profondes animant les agents et les sujets. À cette fin, trois champs sont investis : les trajectoires de mobilisation, les structurations socio-économiques sous-jacentes et la nature des revendications. À la croisée du droit et de la science politique, E-révolutions et révolutions remet en cause les clichés et propose une nouvelle lecture des révoltes qui ont secoué le monde arabo-musulman en 2011 et 2012. Il analyse les jeux de miroirs déformants véhiculés par les technologies numériques, les mécanismes de régulation émergents et l’apparition d’un nouvel acteur : le contestataire-participant.The so-called “Arab Springs” give rise to a number of myths and phantasms, and a lot of texts only consider the surface of movements, with both fascination and exaltation about social networks. But the digital expression of contestation is not sufficient to explain the phenomenon. It is preferable to consider deep reasons moving agents and subjects, within three fields of investigation: mobilization trajectories, underlying socio-économic structurations, and the nature of the revendications. At the crossroads of law and political science, E-révolutions et révolutions shatters clichés and gives a new vision of revolts in Arabo-Muslim world in 2011 and 2012

Multidisciplinary approaches for the study of sediment discharges to the Mediterranean Sea to mitigate the impact of climate and anthropogenic activities on coastal environments

International audienc