Efficient Decoding Algorithms for the Compute-and-Forward Strategy

We address in this paper decoding aspects of the Compute-and-Forward (CF) physical-layer network coding strategy. It is known that the original decoder for the CF is asymptotically optimal. However, its performance gap to optimal decoders in practical settings are still not known. In this work, we develop and assess the performance of novel decoding algorithms for the CF operating in the multiple access channel. For the fading channel, we analyze the ML decoder and develop a novel diophantine approximation-based decoding algorithm showed numerically to outperform the original CF decoder. For the Gaussian channel, we investigate the maximum a posteriori (MAP) decoder. We derive a novel MAP decoding metric and develop practical decoding algorithms proved numerically to outperform the original one

Discovering Reference Process Models in the Context of BPM Projects

AbstractThis paper is related to process mining, specifically the processes’ discovery. Our goal, through this research work, is to build an approach that extracts a reference model, modeled in BPMN language, from the event logs related to different processes, based on the algorithm α. We also aim to make the configuration of the extracted process models in BPMN language. So, we developed a plug-in in ProM environment. We tested this plug-in by using test cases for which preliminary results are encouraging

On the diversity of the Naive Lattice Decoder

International audience"Naive Lattice Decoding" (NLD) and its lowcomplexity approximations such as lattice reduction-aided linear decoders represent an alternative to Maximum Likelihood lattice decoders for MIMO systems. Their diversity order has been investigated in recent works. These showed that the NLD achieves only the receive diversity and that MMSE-GDFE left preprocessing followed by NLD or its approximations achieves the maximum diversity. All the theoretical results have so far focused on the diversity order but this is not the only relevant parameter to achieve good performance and the coding gain also needs to be considered. In addition, up to now there has not been any numerical analysis of the actual performance of these techniques for the coded systems for moderate SNR. In this paper, we consider MIMO systems using high-dimensional perfect space-time codes. We show that by adding MMSEGDFE preprocessing, the NLD has a loss of only 1.5 dB with respect to optimal decoding in the case of the Perfect Code 4 × 4. However, even with MMSE-GDFE preprocessing, the performance of lattice-reduction aided linear receivers is still very poor for high-dimensional lattices

Morphological effect of dichloromethane on alfalfa (Medicago sativa) cultivated in soil amended with fertilizer manures

In this work, we investigated the morphological effect of dichloromethane (DCM) on alfalfa (Medicago sativa) plant. We studied in vitro the influence of its concentration on alfalfa germination. The plants were placed in pots for 15 weeks, and exposed to increasing concentrations of DCM (50 µg L−1 and 84 mg L−1). In addition, we examined the effect of two manures (cow and sheep), which were applied to a contaminated soil, on alfalfa plant growth. The effect of the presence of dichloromethane is obvious even in plant–soil manure system. In fact, in the event of contamination, the soil–cow manure mixture represents the best setting medium for the Alfalfa plant compared to other environments, regardless of the contamination level. Indeed, the presence of two types of manure does not allow the suppression of the inhibitory effect of dichloromethane on the mass of the dry matter of the aerial part which is 18.38% for the cow manure-amended soil and 13.96% for the sheep manure-amended soil

Functional Exploitation of Carob, Oat Flour, and Whey Permeate as Substrates for a Novel Kefir-Like Fermented Beverage: An Optimized Formulation

This study investigated the fortification of a carob-based kefir-like beverage (KLB) with whey permeate (WP) and oat flour (OF). The response surface method was used to show the effect of WP and OF concentrations on lactic acid bacteria and yeast cell densities, pH, total titratable acidity (TTA), total phenolics content (TCP), DPPH radical scavenging activity, and overall acceptability (OA) in KLB. The statistical design provided thirteen formulations where OF concentration varied from 3% to 5% and WP from 10% to 15%. The enrichment of carob pods decoction with WP and OF had a positive effect on biomass production. Overall fermentation was shown to increase TPC of KLB. Furthermore, OF supplementation led to the higher levels of TPC and antiradical activity. WP negatively affected OA at linear and quadratic levels, whereas no effect of OF was observed at the linear level. The optimum point was found by using WP at 11.51% and OF at 4.77%. Optimized KLB resulted in an enrichment of bioavailable phenolics derivatives and highly digestible proteins

Multi-user communication systems : from interference management to network coding

Ce travail est dédié à l'analyse, la conception et l'évaluation des performances des schémas de codage de réseaux pour les systèmes des communications multi-terminaux. Nous étudions en premier lieu le protocole « compute-and-forward » dans le canal à accès multiples. Nous proposons un critère de construction de codes de réseaux efficaces pour cette stratégie basé sur la résolution d'un problème du vecteur le plus court d'un réseau de points. En addition, nous développons de nouveaux algorithmes de décodage prouvés numériquement plus performants que le décodeur existant du CF. La deuxième partie concerne l'implémentation du protocole CF dans le canal à relais bidirectionnel et le canal à sources et relais multiples. Nous développons des algorithmes de construction de schémas de codage pour le CF et évaluons théoriquement et par simulations numériques leurs performances. La dernière partie concerne le canal MIMO distribué et en particulier une nouvelle architecture de décodeurs « integer forcing » inspirés par le protocole CF. Nous proposons de nouveaux algorithmes de construction des paramètres optimaux de ces décodeurs et montrons par simulations qu'ils apportent un gain significatif par rapport aux récepteurs linéaires existantsThis work is dedicated to the analysis, design and performance evaluation of physical layer network coding strategies in multiuser communication systems. The first part is devoted to study the compute-and-forward protocol in the basic multiple access channel. For this strategy, we propose an optimal solution to design efficient network codes based on solving a lattice shortest vector problem. Moreover, we derive novel bounds on the ergodic rate and the outage probability for the CF operating in fast and slow fading channels respectively. Besides, we develop novel decoding algorithms proved numerically to outperform the traditional decoding scheme for the CF. The second part is dedicated to the design and end-to-end performance evaluation of network codes for the CF and the analog network coding in the two-way relay channel and the multi-source multi-relay channel. For each network model we study the decoding at the relay nodes and the end destination, propose search algorithms for optimal network codes for the CF and evaluate, theoretically and numerically, the end-to-end error rate and achievable transmission rate. In the last part, we study new decoders for the distributed MIMO channel termed integer forcing (if). Inspired by the CF, if receivers take advantage of the interference provided by the wireless medium to decode integer linear combinations of the original codewords. We develop in our work efficient algorithms to select optimal if receivers parameters allowing to outperform existing suboptimal linear receiver

Systèmes de communications multi-utilisateurs : de la gestion d'interférence au codage réseau

This work is dedicated to the analysis, design and performance evaluation of physical layer network coding strategies in multiuser communication systems. The first part is devoted to study the compute-and-forward protocol in the basic multiple access channel. For this strategy, we propose an optimal solution to design efficient network codes based on solving a lattice shortest vector problem. Moreover, we derive novel bounds on the ergodic rate and the outage probability for the CF operating in fast and slow fading channels respectively. Besides, we develop novel decoding algorithms proved numerically to outperform the traditional decoding scheme for the CF. The second part is dedicated to the design and end-to-end performance evaluation of network codes for the CF and the analog network coding in the two-way relay channel and the multi-source multi-relay channel. For each network model we study the decoding at the relay nodes and the end destination, propose search algorithms for optimal network codes for the CF and evaluate, theoretically and numerically, the end-to-end error rate and achievable transmission rate. In the last part, we study new decoders for the distributed MIMO channel termed integer forcing (if). Inspired by the CF, if receivers take advantage of the interference provided by the wireless medium to decode integer linear combinations of the original codewords. We develop in our work efficient algorithms to select optimal if receivers parameters allowing to outperform existing suboptimal linear receiversCe travail est dédié à l'analyse, la conception et l'évaluation des performances des schémas de codage de réseaux pour les systèmes des communications multi-terminaux. Nous étudions en premier lieu le protocole « compute-and-forward » dans le canal à accès multiples. Nous proposons un critère de construction de codes de réseaux efficaces pour cette stratégie basé sur la résolution d'un problème du vecteur le plus court d'un réseau de points. En addition, nous développons de nouveaux algorithmes de décodage prouvés numériquement plus performants que le décodeur existant du CF. La deuxième partie concerne l'implémentation du protocole CF dans le canal à relais bidirectionnel et le canal à sources et relais multiples. Nous développons des algorithmes de construction de schémas de codage pour le CF et évaluons théoriquement et par simulations numériques leurs performances. La dernière partie concerne le canal MIMO distribué et en particulier une nouvelle architecture de décodeurs « integer forcing » inspirés par le protocole CF. Nous proposons de nouveaux algorithmes de construction des paramètres optimaux de ces décodeurs et montrons par simulations qu'ils apportent un gain significatif par rapport aux récepteurs linéaires existant

Traduire les marqueurs de la littérarité. De la déformation à l’erreur culturelle

Introduction Traduire un texte littéraire reste un exercice épineux à plus d’un titre. Comme il s’agit d’un texte qui joue sur le code de la langue, tout détail devient signifiant. Le propre de ce type de textes est de transcender le génie de la langue et d’innover les images et les structures. C’est ce qui fait de l’écriture littéraire un processus, une écriture dynamique qui signifie aussi bien par l’ensemble des éléments qu’elle met en œuvre que par l’émotion qu’elle suscite chez le lecteu..

Does auditor quality affect firms' investment decisions in MENA countries?

International audienc