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The energy consumption is considered to be the major challenge in wireless sensor networks. In this paper, we shed light on a new approach to overcome the energy consumption problems. The objective of this work is to integrate an improved algorithm which is the K-means to create a balanced energy on clusters and to use the Gaussian elimination algorithm during the election of cluster head that will guarantee the distribution of energy consumption. To address the problem of the optimal number of groups, we use Davies Bouldin index to increase the network lifetime. The simulation result shows that the proposed protocol extends the network lifetime compared to Leach, iMod-Leach, leach-C, and CELRP. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) are used to retrieve information in hostile environments that are not always accessible to human beings. Once they are deployed, the sensors are considered autonomous. Their lifetime is equivalent to the lifetime of their battery. The energy factor is the center of all the concerns of the sensors: economic routing protocols, adapted wireless technology, etc. Energy costs must be minimized because energy is a key constraint in sensor networks. This paper is part of the study of the routing problem in WSNs. Indeed, the problem consists of the nodes located around the base station (BS), which transmit data to other nodes, their energy is depleted more quickly. This causes energy holes and areas called hot spot. To address this problem, we used the unequal clustering mechanism in order to solve the network hot spot problem. Clusters closer to the BS have smaller sizes than those farther from the BS to overcome the energy over-consumption around the BS. The evaluation of our solution will be carried out using the platform Omnet++/Castalia. The simulation results obtained allow a glimpse of the energy gained by the proposed protocol compared to the protocol Eeuc. Energy efficiency is achieved thanks to the use of a network management policy which enables to balance the energy levels of different nodes, consequently, extends the lifetime of the network. • The hierarchical architecture in Wireless Sensor Networks (WSN) has been widely adopted. • A new routing algorithm Multi Hop based Competition Radius is developed aiming to increase the WSN's life time. • Simulation results show that the proposed algorithm presents efficient results in terms of network lifetime, Latency and energy consumption. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a theoretical and practical study of a single phase photovoltaic conversion system. It consists of a step down converter to charge a battery with the maximum power available from photovoltaic generator (PVG) and a single phase voltage source inverter (VSI) to produce a stable AC voltage (220V/50Hz) with lower total harmonic distortion (THD). A new perturb and observe algorithm is designed and implemented in a cheaper microcontroller PIC 16F876 where the duty cycle perturbation and the sampling period are selected to insure the stability of the PV system around the maximum power. The control strategy adopted for the inverter is the Selective Harmonic Eliminated Pulse Width Modulation (SHE PWM). The pulses are calculated and transferred on the PIC 16F876 memory. With this technique, inverter losses are decreased and the output voltage is easily filtered with a simple low pass filter producing a perfectly sine wave form voltage. The battery is sized to supply loads in non-sunny times. With optimization of its various components, the conventional single phase PV system has a low cost, high efficiency but also good power quality which represents a good opportunity to use it in many stand alone photovoltaic applications such as houses lighting. An experimental system has been made to demonstrate the efficiency of the photovoltaic system and to validate simulations done by Matlab–Simulink environment. [Copyright &y& Elsevier]