Abdelaziz Amraoui

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We investigate the behavior of iteratively decoded low-density parity-check (LDPC) codes over the binary erasure channel in the so-called ldquowaterfall region.rdquo We show that the performance curves in this region follow a simple scaling law. We conjecture that essentially the same scaling behavior applies in a much more general setting and we provide(More)
We investigate the finite-length scaling methodology for irregular LDPC code ensembles when transmission takes place over the binary erasure channel (BEC). We first show how the necessary computations, namely the covariance evolution and the computation of the finite-length shift, can be accomplished in the irregular case. We then investigate how the(More)
— We explain how to optimize finite-length LDPC codes for transmission over the binary erasure channel. Our approach relies on an analytic approximation of the erasure probability. This is in turn based on a finite-length scaling result to model large scale erasures and a union bound involving minimal stopping sets to take into account small error events.(More)
Consider communication over the binary erasure channel BEC(ǫ) using random low-density parity-check codes with finite-blocklength n from 'standard' ensembles. We show that large error events is conveniently described within a scaling theory, and explain how to estimate heuristically their effect. Among other quantities, we consider the finite length(More)
We show that the finite-length scaling parameters for irregular LDPC codes when used over the binary erasure channel can be computed without resorting to "covariance evolution". We provide simple expressions that can be evaluated using solely the degree distributions and the characteristics of the fixed point of density evolution
Anthrax is a disease caused by Bacillus anthracis. The disease affects primarily herbivores including sheep, cattle, horses, and other domestic animals. Humans may rarely be affected. We examined one male and two female patients with a localised itchy erythematous papule of the eyelid. A necrotising ulcer formed in each of the three cases resulting in a(More)
Ten cases of intra-orbital hydatid cysts were operated from January 85 to December 91. The aim of this retrospective study is to show the importance of this pathology with regard to other intra-orbital expansive processes and to discuss the efficiency of neurosurgical approaches. The mean age was 25 years, with 5 women and 5 men. The symptoms consisted in(More)
Subperosteal hematoma is rarely associated with extradural hematoma and orbital roof fracture. We report a case observed in a 16-year-old boy who developed exophthalmos, diplopia and visual loss after blunt head trauma. Computed tomography demonstrated the subperiosteal hematoma associated with a thin extradural hematoma and an orbital roof fracture. The(More)