A new modification of LEACH for efficient energy in WSN

The limited energy of nodes in wireless sensor networks and the impossibility of replacing their batteries, have lead to protocols development which optimize and balance the energy consumption over the network. LEACH is the most used hierarchical protocol. However, one major weakness of the LEACH protocol lies in both of its random cluster formation and cluster head election. In this paper, we present two new protocols based virtual grid clustering on coverage area. In the first one, sensing area is devided into grids as squares named as VSG-LEACH and in the second one into grids as hexagons named as VHG-LEACH. In each zone, one cluster head is elected according to its residual energy and its distance from the cell center. The simulation results show that the network lifetime is prolonged by 169.67% and the energy consumption is improved by 80.97% compared to LEACH protocol

EDK-LEACH: improving LEACH protocol-based machine learning in wireless sensor networks

In wireless sensor networks (WSNs), many sensor devices are spread throughout the environment with the goal of collecting data and sending them to a base station (BS) for further studies. The issue of their limited battery power has aroused the interest of researchers, and several protocols were developed to optimize energy use and thus increase the network’s lifetime. The present research enhances the well-known low-energy adaptive clustering hierarchy (LEACH) protocol with a new artificial intelligence (AI) protocol named energy distance K-means LEACH (EDK-LEACH). For this purpose, an innovative clustering strategy built on the machine learning K-means algorithm is used in WSNs to improve the cluster formation process and maximise network stability. By implementing an objective function that considers each node’s residual energy and distance from the cluster centre when selecting the cluster head (CH) of each cluster, EDK-LEACH also eliminates the inherent randomness in LEACH during the CH election process. The proposed protocol has the advantage of ensuring better CH distribution throughout the network surface with a balanced load across all network nodes. In comparison with the known LEACH, the simulation results demonstrate the efficiency of our approach: the lifetime of the network is extended and the energy consumption is reduced

CAS-MINE: Providing personalized services in context-aware applications by means of generalized rules

Context-aware systems acquire and exploit information on the user context to tailor services to a particular user, place, time, and/or event. Hence, they allowservice providers to adapt their services to actual user needs, by offering personalized services depending on the current user context. Service providers are usually interested in profiling users both to increase client satisfaction and to broaden the set of offered services. Novel and efficient techniques are needed to tailor service supply to the user (or the user category) and to the situation inwhich he/she is involved. This paper presents the CAS-Mine framework to efficiently discover relevant relationships between user context data and currently asked services for both user and service profiling. CAS-Mine efficiently extracts generalized association rules, which provide a high-level abstraction of both user habits and service characteristics depending on the context. A lazy (analyst-provided) taxonomy evaluation performed on different attributes (e.g., a geographic hierarchy on spatial coordinates, a classification of provided services) drives the rule generalization process. Extracted rules are classified into groups according to their semantic meaning and ranked by means of quality indices, thus allowing a domain expert to focus on the most relevant patterns. Experiments performed on three context-aware datasets, obtained by logging user requests and context information for three real applications, show the effectiveness and the efficiency of the CAS-Mine framework in mining different valuable types of correlations between user habits, context information, and provided services

Complexation of manganese(II), cobalt(II), nickel(II) and copper(II) by a ligand derived from 1,2,4-triazole: Potentiometric studies and Density Functional Theory calculations

DFT calculations have been conducted to understand the conformational and tautomeric preference of 4-amino-5-(2-hydroyphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione ligand. The results suggest that the thione tautomer is found to be the most stable form in the gas phase, which is in very good agreement with the FT-IR and crystallographic data. The protonation constants of the ligand and the stability constants of its complexes with Mn(II), Co(II), Ni(II) and Cu(II) have been determined by potentiometry in water-ethanol (90:10, v:v) mixture. The absolute pKa values of the ligand have been calculated using DFT method to complement and help the assignment of potentiometric data. DFT calculations have also been carried out for some metallic complexes species formed in solution in order to propose their most probable structures

Categorization of the context within the medical domain

The context itself has multiple meanings may vary according to the domain of application. This contextual flexibility was behind the emergence of so such huge number of context definitions. Nevertheless, all the proposed definitions do not provide solid ground for systems developers’ expectations, especially in healthcare domain [1]. This issue prompted researchers to divide the context into a set of concepts that would facilitate organizing of contextual knowledge. The conventional taxonomies of context are always too complex, and we need to fight to make them useful in the intended application area. In this paper, we propose a new context classification which covers almost all the context aspects that we may need to develop a tele-monitoring system for chronic disease management

Étude d'une commande vectorielle d'une machine asynchrone commandée en courant et utilisant des correcteurs flous

109 p. : ill. ; 30 cmGrace aux récent progrès de l'électronique de puissance et des techniques numériques, le principe de la machine à courant continu est exploité au niveau des machines asynchrone par la technique du flux orienté. Cependant cette méthode ne donne de bons résultats que si la position du flux est connue avec précision. La variation des paramètres de la machine, principalement la résistance rotorique, engendre une erreur sur cette position. En conséquence les performances de la machine sont fortement affectées. Notre étude est faite dans le cas d'une machine asynchrone alimentée en tension à travers un onduleur commandé en courant par la technique d'hystérésis. La modélisation de la machine est suivie de plusieurs simulations. Les résultats de cas simulations ont montré que le régulateur IP donne de meilleurs résultats que le IP au niveau du rejet de la perturbation. L'application de la régulation floue permet d'améliorer davantage ces résultats. En effet cela s'explique par le caractère non-linéaire du régulateur flou. Afin de maintenir le découplage même quand est paramètre de la machine varient, une boucle d'adaptation de la résistance rotorique est ajouté. Cette méthode présent l'avantage d'être simple et de ne pas nécessiter un matériel supplémentaire. L'objectif de ce travail est l'étude de l'apport de la logique floue à la commande des machines asynchrone

Etude de la qualité physico-chimique, microbiologique, sensorielle et les propriétés antioxydantes de la confiture de grenade

68 p. : ill. ; 30 cm. (+ CD-Rom)L'objectif principal de cette étude est l’élaboration d’une confiture à base du fruit de grenade « Punica granatum ». L’étude a été menée sur la variété « Lahlou » récolté dans la région Larbaâ Nath Irathen de la wilaya de Tizi-Ouzou, qui vise à la fois la sauvegarde du patrimoine phytogénétique de la région et la mise au point d’un nouveau produit alimentaire de type biologique, énergétique et salubre. Dans cette étude, nous nous sommes intéressés d’une part à élaborer une recette appropriée pour la transformation de la grenade en confiture avec deux formulations, d’autre part d’évaluer les caractéristiques microbiologiques, sensorielles, physicochimiques, la détermination du contenu en antioxydant et l’évaluation des propriétés antioxydantes pour les deux confitures élaborées. Les résultats d’analyses physico-chimiques indiquent que les confitures de grenade étudiées présentent des propriétés assez comparables à d’autres confitures issues d’autres fruits. Les analyses microbiologiques réalisées ont révélé que les confitures élaborées sont indemne de tous germes de contamination. Quant aux antioxydants, les confitures renferment une quantité considérable liée à une activité antioxydante importante. En revanche, l’analyse sensorielle a démontré que la confiture contenant cinq cent gramme de sucre est beaucoup plus appréciée par les dégustateurs que celle contenant moins de sucre.En conclusion, les confitures de grenade élaborées présentent des paramètres technologiques conquérants aux autres confitures connues et qui permettent sa commercialisation avec sucés