Low-rate coding using incremental redundancy for GLDPC codes

In this paper we propose a low-rate coding method, suited for application-layer forward error correction. Depending on channel conditions, the coding scheme we propose can switch from a fixed-rate LDPC code to various low-rate GLDPC codes. The source symbols are first encoded by using a staircase or triangular LDPC code. If additional symbols are needed, the encoder is then switched to the GLDPC mode and extra-repair symbols are produced, on demand. In order to ensure small overheads, we consider irregular distributions of extra-repair symbols optimized by density evolution techniques. We also show that increasing the number of extra-repair symbols improves the successful decoding probability, which becomes very close to 1 for sufficiently many extra-repair symbols

Electrochemical impedance spectroscopy to study physiological changes affecting the red blood cell after invasion by malaria parasites

The malaria parasite, Plasmodium falciparum, invades human erythrocytes and induces dramatic changes in the host cell. The idea of this work was to use RBC modified electrode to perform electrochemical impedance spectroscopy (EIS) with the aim of monitoring physiological changes affecting the erythrocyte after invasion by the malaria parasite. Impedance cell-based devices are potentially useful to give insight into cellular behavior and to detect morphological changes. The modelling of impedance plots (Nyquist diagram) in equivalent circuit taking into account the presence of the cellular layer, allowed us pointing out specific events associated with the development of the parasite such as (i) strong changes in the host cell cytoplasm illustrated by changes in the film capacity, (ii) perturbation of the ionic composition of the host cell illustrated by changes in the film resistance, (iii) releasing of reducer (lactic acid or heme) and an enhanced oxygen consumption characterized by changes in the charge transfer resistance and in the Warburg coefficient characteristic of the redox species diffusion. These results show that the RBC-based device may help to analyze strategic events in the malaria parasite development constituting a new tool in antimalarial research

A DFT study of the NO adsorption on Pdn (n = 1–4) clusters

We report a density-functional study of some properties of the adsorption process of the NO molecule on small palladium clusters (n = 1–4). The interaction between NO and the Pdn clusters is studied on various adsorption sites. Both, NO and Pdn geometrical relaxations are taken into account. The significant conformational reconstruction of the metallic cluster upon NO adsorption induces a large decrease of the NO adsorption energy. Nevertheless, the N–O binding energy is strongly weakened when the molecule is adsorbed on the small Pdn clusters due essentially to an electrostatic repulsion between both N and O atoms. The possible dissociation process of NO on Pd4 cluster is then investigated within two processes: the NO molecule does not dissociate on Pd4 with process (i) (dissociation of the isolated gas phase NO molecule followed by the adsorption of both nitrogen and oxygen atoms on the cluster). Process (ii)which presents three successive steps (adsorption of the NO molecule, dissociation of the NO molecule adsorbed on Pd4, adsorption of the O atom on the cluster) is studied in details and we propose a reaction pathway locating transition states and intermediate species. The activation energy for process (ii) is high and the dissociation of the NO molecule on the Pd4 cluster is thus highly improbable

Les Déterminants De L’accès Aux Services De Santé À Grand Bassam

State of complete physical, mental and social well-being, health is fundamental for man. Yet global figures for access to health are alarming. According to Gijs (2011) 2.5 billion people in the world do not have access to basic health care. In Côte d'Ivoire, the State has made population access a priority. Thus, sanitary infrastructures were built and equipped (PNDS, 2016). However, the problem of access to health services remains. The city of GrandBassam, located in the south-east of Côte d'Ivoire, has a wide range of health structures. Yet there are still people who still do not have access to health care. According to the RASS (2015), 25% of the population of Grand-Bassam still does not use health services. The purpose of this article is to identify the determinants of the access of the population of Grand-Bassam to health services. The methodological approach adopted to conduct this study took into account a bibliographic synthesis and the administration of a questionnaire. This study shows that perception of distance, income of head of household, perception of cost of care, household size, educational level, and age of households are the factors that determine access health services in the city of Grand-Bassam

Tuning EASY-Backfilling Queues

International audienceEASY-Backfilling is a popular scheduling heuristic for allocating jobs in large scale High Performance Computing platforms. While its aggressive reservation mechanism is fast and prevents job starvation, it does not try to optimize any scheduling objective per se. We consider in this work the problem of tuning EASY using queue reordering policies. More precisely, we propose to tune the reordering using a simulation-based methodology. For a given system, we choose the policy in order to minimize the average waiting time. This methodology departs from the First-Come, First-Serve rule and introduces a risk on the maximum values of the waiting time, which we control using a queue thresholding mechanism. This new approach is evaluated through a comprehensive experimental campaign on five production logs. In particular, we show that the behavior of the systems under study is stable enough to learn a heuristic that generalizes in a train/test fashion. Indeed, the average waiting time can be reduced consistently (between 11% to 42% for the logs used) compared to EASY, with almost no increase in maximum waiting times. This work departs from previous learning-based approaches and shows that scheduling heuristics for HPC can be learned directly in a policy space

Ozone LIDAR as an Analytical Tool in Effective Air Pollution Management: The Geneva 96 Campaign

The LIDAR (LIght Detection And Ranging) technique has developed into one of the practical high performance techniques for conducting air quality and meteorological measurements. DIfferential Absorption Lidar (DIAL) is used for measuring trace gases, including pollutants like ozone at low concentrations. Multiple wavelengths backscatter and depolarization measurements give information about particles in the atmosphere, and single wavelength lidar can be used for meteorological measurements like wind velocity and temperature. Range resolved in situ data obtained by lidar can play a significant role in our understanding of the air quality in the planetary boundary layer, particularly when applied in conjunction with air quality models. This is because DIAL can be used to measure concentrations in three dimensions in real time with a spatial resolution that corresponds well to that used in the model calculations. Thus one obtains an advantage when comparing with point measurements at or near ground level which are often perturbed by local emissions. A summary of the lidar principle is presented here, followed by different examples of vertical ozone profiles and time series obtained with a new optical layout of the EPFL-LPAS DIAL system using dual telescope detection. These data were obtained during the summer 96 field campaign in the Geneva area. Results are then compared with the mesoscale Eulerian model calculations performed in our laboratory. The overall results provide new insight into air pollution dynamics in the Geneva area and calculations are under way, using the model adjusted by the measurements, to optimize air pollution abatement strategies under certain atmospheric conditions in this part of Switzerland

Extended point defects in crystalline materials: Ge and Si

B diffusion measurements are used to probe the basic nature of self-interstitial 'point' defects in Ge. We find two distinct self-interstitial forms - a simple one with low entropy and a complex one with entropy ~30 k at the migration saddle point. The latter dominates diffusion at high temperature. We propose that its structure is similar to that of an amorphous pocket - we name it a 'morph'. Computational modelling suggests that morphs exist in both self-interstitial and vacancy-like forms, and are crucial for diffusion and defect dynamics in Ge, Si and probably many other crystalline solids

Coherent Control of Mid-Infrared Frequency Comb by Optical Injection of Near-Infrared Light

We demonstrate the use of a low power near-infrared laser illuminating the front facet of a quantum cascade laser (QCL) as an optical actuator for the coherent control of a mid-infrared frequency comb. We show that by appropriate current control of the QCL comb and intensity modulation of the near-infrared laser, a tight phase lock of a comb line to a distributed feedback laser is possible with 2 MHz of locking bandwidth and 200 mrad of residual phase noise. A characterization of the whole scheme is provided showing the limits of the electrical actuation which we bypassed using the optical actuation. Both comb degrees of freedom can be locked by performing electrical injection locking of the repetition rate in parallel. However, we show that the QCL acts as a fast near-infrared light detector such that injection locking can also be achieved through modulation of the near-infrared light. These results on the coherent control of a quantum cascade laser frequency comb are particularly interesting for coherent averaging in dual-comb spectroscopy and for mid-infrared frequency comb applications requiring high spectral purity

De l’intérêt des pictogrammes pour figurer les représentations sociocognitives de l’espace résidentiel

Quel rapport émotionnel un individu entretient-il avec son habitat ? Un jeu de simulation de négociation entre les différents critères d’évaluation de l’environnement résidentiel permet de recueillir un corpus de données. Son analyse implique une réflexion sur la formalisation des résultats obtenus. Deux options sont confrontées : une représentation en graphe polaire et une image composée de pictogrammes symbolisant les multiples dimensions de l’espace résidentiel qui peuvent motiver les choix d’installation. Cette dernière image permet une appréhension plus simple du lien entre les structures spatiales, cognitives et sociales.What emotional relationship does an individual have with his habitat? A negotiation simulation game between the different criteria of evaluation of the residential environment makes it possible to collect a corpus of data. Its analysis implies a reflection on the formalization of the results obtained. Two options are confronted: a polar graph representation and an image composed of pictograms symbolizing the multiple dimensions of the residential space that can motivate settlement choices. This latter image allows a simpler apprehension of the link between spatial, cognitive and social structures.¿Cuál es la relación emocional de un individuo con su hábitat?. Un juego de simulación para la negociación pemite recopilar información a partir de criterios de evaluación del entorno residencial. Su análisis implica una reflexión sobre la formalización gráfica de los resultados obtenidos. Se confrontan dos opciones de representación que pueden motivar la elección o no de una ubicación: una gráfica polar y una imagen compuesta por pictogramas que simbolizan las múltiples dimensiones del espacio residencial. Esta última imagen visibiliza mejor las relaciones entre las estructuras espaciales, cognitivas y sociales