Distributed and Load-Adaptive Self Configuration in Sensor Networks

Proactive self-configuration is crucial for MANETs such as sensor networks, as these are often deployed in hostile environments and are ad hoc in nature. The dynamic architecture of the network is monitored by exchanging so-called Network State Beacons (NSBs) between key network nodes. The Beacon Exchange rate and the network state define both the time and nature of a proactive action to combat network performance degradation at a time of crisis. It is thus essential to optimize these parameters for the dynamic load profile of the network. This paper presents a novel distributed adaptive optimization Beacon Exchange selection model which considers distributed network load for energy efficient monitoring and proactive reconfiguration of the network. The results show an improvement of 70% in throughput, while maintaining a guaranteed quality-of- service for a small control-traffic overhead

Dynamic symmetrical topology models for pervasive sensor networks

The success of pervasive computing environments using ubiquitous loco-dynamic sensing devices is very dependent upon the sensor deployment topology (DT) employed. This paper presents a systematic mathematical model for efficient sensor deployment and provides a comparison with other popular topologies. The model focuses upon blanket coverage of a surveillance area using a minimum number of sensing devices, with minimal infra-sensor overlapping to reduce collisions and co-existence problems. Simulation results are presented for the hexagonal, triangular and square grid topologies for various dimensions of surveillance area. The results confirm that the hexagonal model gives optimal performance in terms of requiring the minimal number of sensors. The paper also highlights the improved performance of ubiquitous wireless sensor networks when a hexagonal topology (HT) is used

Online Load Balancing for Energy-Aware Anycast Routing

Anycast routing offers a flexible paradigm for resource constrained, ad hoc sensor networks, where sensors can route data to any available server. The selection policy of servers in an anycast scenario could assist in keeping the network operating quiescently for a required time frame. This paper proposes a novel load balancing model to make anycast routing decisions based on route efficiency, and remaining life-times of the servers. The model makes use of the historical load and channel capacity profiles to accurately estimate the remaining life of each server. The results show that the proposed technique achieves effective reconfiguration performance to meet the network time-to-live requirement and also maintains better load-balance with anycast routing protoco

HUSEC: A heuristic self configuration model for wireless sensor networks

The Network State Beacons (NSB) exchange rate is the critical parameter in monitoring the dynamic state of any self-configuring ad hoc sensor network. Along with the network state and the overhead control traffic, it determines both the time and nature of any proactive reconfiguration activity that is necessary to counteract any degradation in network performance. While traditionally selected at random, this rate of beacon exchange significantly affects the accuracy with which the variations in network state are tracked. It is therefore imperative to adapt this rate to the variation in load profile and attempt to maintain its value within predefined bounds which can be optimised to keep the network operating quiescently, while conforming to its various Quality-of-Service (QoS) requirements. This paper presents a novel, heuristic self-configuration (HUSEC) model which addresses this optimisation problem. The simulation results confirm that the model reconfigures the network more effectively to not only achieve higher throughput, but also greater network integrity, with minimal control traffic and resource overheads

A Cross-Layer Data Dissemination Protocol for Energy Efficient Sink Discovery in Wireless Sensor Networks

This paper proposes a cross-layer protocol for energy-aware routing in wireless sensor networks. The protocol combines the energy depreciation rate, node distance and neighbourhood information from physical layer together with TDMA schedules from the MAC layer and also network life requirements from the application layer, to effectively determine the most efficient routes to the base station. This cross layer efficiency measure is then used to form dynamic clusters that adapt to changing traffic and energy conditions so assisting to both control the transmission power and schedule the sleep-wake cycles of nodes for better energy utilisation. The proposed protocol is a recursive aggregation scheme that transforms a network-wide routing dissemination problem into a single hop query protocol that aids nodes in making multi-hop routing decisions based solely upon the information provided by their single-hop neighbours. Results confirm that the proposed technique balances the load on forwarding nodes, adapts the MAC layer precisely to the routing layer and minimizes data delivery time for increased traffic and large scale networks

Insight into the Exemplary Physical Properties of Zn-Based Fluoroperovskite Compounds XZnF3 (X = Al, Cs, Ga, In) Employing Accurate GGA Approach: A First-Principles Study

Using the full-potential linearized augmented plane wave (FP-LAPW) method, dependent on density functional theory, the simple cubic ternary fluoroperovskites XZnF3 (X = Al, Cs, Ga, In) compound properties, including structural, elastic, electronic, and optical, are calculated. To include the effect of exchange and correlation potentials, the generalized gradient approximation is applied for the optimization operation. This is identified, when we are changing the metallic cation specified as “X” when shifting to Al from Cs, the value of the bulk modulus is found to increase, showing the rigidity of a material. Depending upon the value of the bulk modulus, we can say that the compound AlZnF3 is harder and cannot be compressed as easily as compared to the other three compounds, which are having a lower value of the bulk modulus from AlZnF3. It is also found that the understudy compounds are mechanically well balanced and anisotropic. The determined value of the Poisson ratio, Cauchy pressure, and Pugh ratio shows our compounds have a ductile nature. From the computation of the band structure, it is found that the compound CsZnF3 is having an indirect band of 3.434 eV from (M-Γ), while the compounds AlZnF3, GaZnF3, and InZnF3 are found to have indirect band gaps of 2.425 eV, 3.665 eV, and 2.875 eV from (M-X), respectively. The optical properties are investigated for radiation up to 40 eV. The main optical spectra peaks are described as per the measured electronic structure. The above findings provide comprehensive insight into understanding the physical properties of Zn-based fluoroperovskites