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Modern health care system is one of the most popular Wireless Body Area Sensor Network (WBASN) applications and a hot area of research subject to present work. In this paper, we present Reliability Enhanced-Adaptive Threshold based Thermalunaware Energy-efficient Multi-hop ProTocol (RE-ATTEMPT) for WBASNs. The proposed routing protocol uses fixed deployment of wireless sensors (nodes) such that these are placed according to energy levels. Moreover, we use direct communication for the delivery of emergency data and multihop communication for the delivery of normal data. RE-ATTEMPT selects route with minimum hop count to deliver data which downplays the delay factor. Furthermore, we conduct a comprehensive analysis supported by MATLAB simulations to provide an estimation of path loss, and problem formulation with its solution via linear programming model for network lifetime maximization is also provided. In simulations, we analyze our protocol in terms of network lifetime, packet drops, and throughput. Results show better performance for the proposed protocol as compared to the existing one.

We propose forwarding-function ( ) based routing protocol for underwater sensor networks (UWSNs): improved adaptive mobility of courier nodes in threshold-optimized depth-based-routing (iAMCTD). Unlike existing depth-based acoustic protocols, the proposed protocol exploits network density for time-critical applications. In order to tackle flooding, path loss, and propagation latency, we calculate optimal holding time ( ) and use routing metrics: localization-free signal-to-noise ratio (LSNR), signal quality index (SQI), energy cost function (ECF), and depth-dependent function (DDF). Our proposal provides on-demand routing by formulating hard threshold ( th ), soft threshold ( th ), and prime energy limit ( prime ). Simulation results verify effectiveness and efficiency of the proposed iAMCTD. BackgroundUnderwater acoustic sensor networks (UASNs), as a subclass of wireless sensor networks (WSNs), are specifically used for monitoring purposes in aqueous environment. The acoustic wireless sensors along with sink(s), distributed under water, constitute the basic body of UASN, where acoustic sensors gather the information of interest and then following a routing strategy forward these data to the end station. WHOI Micro-Modem [1] and Crossbow Mica2 [2] are among the commercially available sensors for underwater environments. Sink is generally supposed to have no power constraint, whereas the acoustic sensors are equipped with limited battery power. These networks provide diversified range of applications like pollution monitoring, ocean current detection, submarine discovery, deep sea explorations, and seabed management.Due to the nature of aqueous environment, improving energy efficiency at routing layer is a challenging task. Moreover, as there are major differences between terrestrial and underwater conditions, hence the basic concepts of terrestrial routing can not be implemented in UWSNs. To tackle these problems, researchers exercise the role of low speed acoustic signals for aqueous communication and sea navigation systems, leading to high propagation delay and transmission losses. High shipping activity, thermal noise, and turbulent noise also increase the error rate. Authors in [3] design the underwater acoustic channel to descriptively analyze the total noise density and path loss. On the other hand [4], it investigates diverse routing architectures for 2-dimensional and 3-dimensional UWSNs. Fundamental analyses of aqueous conditions show that reactive routing is more challenging than the proactive one. Battery replacement and efficient routing are among the solutions to overcome the

Sensor networks feature low-cost sensor devices with wireless network capability, limited transmit power, resource constraints, and limited battery energy. Cooperative routing exploits the broadcast nature of wireless medium and transmits cooperatively using nearby sensor nodes as relays. It is a promising technique that utilizes cooperative communication to improve the communication quality of single-antenna sensor nodes. In this paper, we propose a cooperative transmission scheme for underwater sensor networks (UWSNs) to enhance the network performance. Cooperative diversity has been introduced to combat fading. Cooperative UWSN (Co-UWSN) is proposed, which is a reliable, energy-efficient, and high throughput routing protocol for UWSN. Destination and potential relays are selected that utilize distance and signal-to-noise ratio computation of the channel conditions as cost functions. This contributes to sufficient decrease in path losses occurring in the links and transferring of data with much reduced path loss. Simulation results show that Co-UWSN protocol performs better in terms of end-to-end delay, energy consumption, and network lifetime. Selected protocols for comparison are energy-efficient depth-based routing (EEDBR), improved adaptive mobility of courier nodes in threshold-optimized depth-based routing (iAMCTD), cooperative routing protocol for UWSN, and cooperative partner node selection criteria for cooperative routing Coop (Re and dth).

In this paper, we propose mathematical optimization models of household energy units to optimally control the major residential energy loads while preserving the user preferences. User comfort is modelled in a simple way, which considers appliance class, user preferences and weather conditions. The wind-driven optimization (WDO) algorithm with the objective function of comfort maximization along with minimum electricity cost is defined and implemented. On the other hand, for maximum electricity bill and peak reduction, min-max regret-based knapsack problem (K-WDO) algorithm is used. To validate the effectiveness of the proposed algorithms, extensive simulations are conducted for several scenarios. The simulations show that the proposed algorithms provide with the best optimal results with a fast convergence rate, as compared to the existing techniques.Appl. Sci. 2015Sci. , 5 1135