Volatile and Non-Volatile Single Electron Memory

Multi Tunnel Junctions (MTJs) have attracted much attention recently in the fields of Single-Electron Devices (SED) in particular Single-Electron Memory (SEM). In this paper, we have design and study a nano-device structure using a two dimensional array MTJs for Volatile and Non-Volatile-SEM, in order to analyze the impact of physical parameters on the performances. We investigate the single-electron circuit characteristics in our devices qualitatively, using single-electron Monte Carlo simulator SIMON. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3192

Méthode d'analyse et de classification des segments du réseau routier supérieur de la région de Montréal

RÉSUMÉ La congestion routière est un phénomène général, considérée comme une externalité extrêmement coûteuse (Prud’homme, 1999). Elle a des effets néfastes sur la prospérité économique d’un pays, le bien-être des individus et la stabilité de l’écosystème. La compréhension de ce phénomène est fondamentale afin que les autorités du transport routier soient en mesure d’apporter des solutions appropriées à ce problème. Ce mémoire présente la méthode d’analyse et de classification des segments du réseau routier supérieur de la grande région montréalaise à partir de leurs caractéristiques physiques, puis étudie la similarité entre cette nouvelle classification et celle obtenue à partir des relevés de temps de parcours observés sur ces différents segments routiers durant la période de pointe du matin (AM). Après avoir recensé, à l’issue d’une revue de littérature, les caractéristiques physiques des routes ayant un lien avec l’état de la circulation, ce document met en avant la méthodologie proposée afin d’atteindre l’objectif maître de ce mémoire. L’approche proposée comporte 5 étapes : faire le montage de la base de données relationnelle, dresser le portrait global du réseau routier échantillonné, synthétiser et agréger les données de facteurs physiques, grouper les tronçons selon leurs caractéristiques physiques, confronter les méthodes de groupement de tronçons et prédire l’appartenance d’un tronçon à un groupe TP à partir des facteurs physiques. Plusieurs outils ont été utilisés pour créer la base de données des facteurs physiques, tels que Google Maps, Street View et ArcGis. Le choix de caractéristiques physiques est fondé sur de multiples études effectuées par divers auteurs sur la thématique de la congestion routière. Au moyen d’un logiciel de traitement de base de données, la table des facteurs physiques a été intégrée avec deux autres tables qui proviennent directement des travaux de Loustau et al.(2009), soit la table des groupes TP et la table d’état de la circulation. Ces travaux consistent à grouper les segments routiers de la grande région de Montréal selon les temps de parcours durant la période de pointe du matin (AM). Une analyse descriptive de la base de données relationnelle qui vise à dresser le portait du réseau routier de la grande région de Montréal, a été menée. En effet, une qualification de l’état de la circulation du réseau routier montréalais a été, au premier lieu, effectué. En second lieu, une analyse descriptive des facteurs physiques des tronçons routiers échantillonnés a été réalisée.-----------ABSTRACT Urban congestion is a general phenomenon, regarded as an extremely costly externality (Prud'homme, 1999). Indeed, congestion has adverse effects on the economy, society and the environment. The urban transportation authorities must understand the congestion phenomenon in order to provide adequate solutions to this problem. This report presents the method of analysis and classification of road segments of the Greater Montreal Region highway system based on their physical characteristics. It then compares this classification to the traffic condition of road sections according to the frequency distribution of travel times observed on these various road sections during the morning rush hour (AM). Following a definition of road congestion and of the indicators to measure it, this paper puts forward the proposed methodology to reach the main objective of this work. The approach is proposed in 5 different steps: to built the relational database, to make a global description of the sampled road system, to summarize and aggregate the data relating to physical factors, to cluster the different sections based on their physical characteristics, to compare the methods with which the sections were grouped together and to predict the TP group of section road. Several tools have been used to create the physical factors database, such as Google Maps, Street View and ArcGIS. The choice of physical characteristics is based on a number of studies carried out by various authors on the subject of urban congestion. Using database management software, the physical factors table has been combined with two other tables taken directly from work done by Loustau and al. (2009), i.e. the TP groups table and the traffic conditions table. These studies consisted in grouping the road sections of the Greater Montreal Region according to travel times during the morning rush hour (AM). A descriptive analysis of the relational database was carried out with the objective of drawing a global picture of the Greater Montreal Region road system. Thus a classification of traffic conditions on the Montreal road network was first made. Then, a descriptive analysis of the physical factors of the sampled road sections was made. Some characteristics turned out to prevail over others: the "highway" type of lanes, the maximum speed authorized, which varies between 70km/h and 100km/h, the very small number of intersections and the number of lanes, which varies between 2 and 3

About modeling and control strategies for scheduling crop irrigation

International audienceWe propose a new simplified crop irrigation model and study the optimal control which consists in maximizing the biomass production at harvesting time, under a constraint on the total amount of water used. Under water scarcity, we show that a strategy with a singular arc can be better than a simple bang-bang control as commonly used. The gain is illustrated on numerical simulations. This result is a promising first step towards the application of control theory to the problem of optimal irrigation scheduling

Phylogeographyc inferences from the mtDNA variation of the three-toed skink, Chalcides chalcides (Reptilia: Scincidae)

Genetic diversity was analyzed in Chalcides chalcides populations from peninsular Italy, Sardinia, Sicily and Tunisia by sequencing 400 bp at the 50 end of the mitochondrial gene encoding cytochrome b (cyt b) and by restriction fragment length polymorphism (RFLP) analysis of two mitochondrial DNA segments (ND-1/2 and ND-3/4). The results of the phylogenetic analysis highlighted the presence of three main clades corresponding with three of the four main geographical areas (Tunisia, Sicily and the Italian peninsula), while Sardinia proved to be closely related to Tunisian haplotypes suggesting a colonization of this island from North Africa by human agency in historical times. On the contrary, the splitting times estimated on the basis of cyt b sequence data seem to indicate a more ancient colonization of Sicily and the Italian Peninsula, as a consequence of tectonic and climatic events that affected the Mediterranean Basin during the Pleistocene. Finally, the analysis of the genetic variability of C. chalcides populations showed a remarkable genetic homogeneity in Italian populations when compared to the Tunisian ones. This condition could be explained by a rapid post-glacial expansion from refugial populations that implied serial bottlenecking with progressive loss of haplotypes, resulting in a low genetic diversity in the populations inhabiting the more recently colonized areas

Steady vs. Dynamic Contributions of Different Doped Conducting Polymers in the Principal Components of an Electronic Nose's Response

Multivariate data analysis and machine-learning classification become popular tools to extract features without physical models for complex environments recognition. For electronic noses, time sampling over multiple sensors must be a fair compromise between a period sufficiently long to output a meaningful information pattern, and sufficiently short to minimize training time for practical applications. Particularly when reactivity's kinetics differ from thermodynamics' in sensitive materials, finding the best compromise to get the most from data is not obvious. Here, we investigate on the influence of data acquisition to improve or alter data clustering for molecular recognition on a conducting polymer electronic nose. We found out that waiting for the sensors to reach their steady state is not required for classification, and that reducing data acquisition down to the first dynamical information suffice to recognize molecular gases by principal component analysis with the same materials. Particularly for online inference, this study shows that a good sensing array is no array of good sensors, and that new figure-of-merits shall be defined for sensing hardware aiming machine-learning pattern-recognition rather than metrology

Optimal control of membrane filtration systems

International audienceThis paper studies an optimal control problem related to membrane filtration processes. A generic mathematical model of membrane fouling is used to capture the dynamic behavior of the filtration process which consists in the attachment of matter onto the membrane during the filtration period and the detachment of matter during the cleaning period. We consider the maximization of the net water production of a membrane filtration system (i.e. the filtrate) over a finite time horizon, where the control variable is the sequence of filtration/backwashing cycles over the operation time of process. Based on the Pontryagin Maximum Principle, we characterize the optimal control strategy and show that it exhibits a singular arc. Moreover we prove the existence of an additional switching curve before reaching the terminal state, and also the possibility of having a dispersal curve as a locus where two different strategies are both optimal