Optimizing the beacon exchange rate for proactive autonomic configuration in ubiquitous MANETs

Proactive self-configuration is indispensable for MANETs like ubiquitous sensor networks (USNs), as component devices of the network are usually exposed to natural or man-made disasters due to the hostile deployment and ad hoc nature of the USNs. Network state beacons (NSBs) are exchanged among the key nodes of the network for crucial and effective monitoring of the network for steady state operation. The rate of beacon exchange (F/sub E/) and its contents, define the time and nature of the proactive action. Therefore it is very important to optimize these parameters to tune the functional response of the USN. This paper presents a comprehensive model for monitoring and proactively reconfiguring the network by optimizing the F/sub E/. The results confirm the improved throughput while maintaining QoS over longer periods of network operation

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

Adaptive Self-Configuration for Distributed Load in Sensor Networks

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 select and update the beacon exchange rate (FX) according to the variations in the load profile of the network. This paper presents a novel localized method that for selecting and updating the FX by adapting to the network load and energy constraints. The results indicating that the model reconfigures the network more effectively to achieve higher throughput as well as greater network integrity, with minimal resource overheads

Coverage Characteristics of Symmetric Topologies for Pervasive Sensor Networks

The success of pervasive computing environments comprising ubiquitous loco-dynamic sensing devices is very dependent upon the coverage characteristics (CCs) of the network topology. These characteristics include blanket coverage, network density, affects on surrounding environments and intra-sensor coverage overlaps. This paper presents a systematic mathematical model to quantitatively investigate the effects of CCs and provides a comparison with other well used topologies e.g. hexagonal, triangular and square grid. The paper uses connectivity, density saturation, conflict regions and effectiveness of the topology as quality parameters in simulation studies for a disaster recovery network in various irregular terrains. Numerical as well as simulation results confirm the improved performance of hexagonal topology (HT) in terms of the above mentioned quality parameters which can be used to tune the network design to ensure the required QoS throughout the life of the network

Optimising Network Control Traffic in Resource Constrained MANETS

The exchange of Network State Beacons (NSBs) is crucial to monitoring the dynamic state of MANETs like sensor networks. The rate of beacon exchange (FX) and the network state define both the time and nature of a proactive action to reconfigure the network in order to combat network performance degradation at a time of crisis. It is thus essential to select the FX within optimized bounds, so that minimal control traffic is incurred due to state maintenance and reconfiguration activities. This paper presents a novel distributed model that selects optimized bounds for FX selection and adapts dynamically to the load profile of the network for energy efficient monitoring and proactive reconfiguration

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

Case study: a smart water grid in Singapore

As aging water distribution infrastructures encounter failures with increasing frequency, there is a real need for integrated, on-line decision-support systems based on continuous in-network monitoring of hydraulic and water quality parameters. Such systems will form the basis of a Smart Water Grid, allowing water utilities to improve optimization of system operation, manage leakage control more effectively, and reduce the duration and disruption of repairs and maintenance. WaterWiSe is an integrated, end-to-end platform for real-time monitoring of water distribution systems that addresses these needs. This paper describes how WaterWiSe's sensing and software platforms have helped improve the operational efficiency of the water supply system in downtown Singapore

Water Distribution System Monitoring and Decision Support Using a Wireless Sensor Network

Water distribution systems comprise labyrinthine networks of pipes, often in poor states of repair, that are buried beneath our city streets and relatively inaccessible. Engineers who manage these systems need reliable data to understand and detect water losses due to leaks or burst events, anomalies in the control of water quality and the impacts of operational activities (such as pipe isolation, maintenance or repair) on water supply to customers. Water Wise is a platform that manages and analyses data from a network of wireless sensor nodes, continuously monitoring hydraulic, acoustic and water quality parameters. Water Wise supports many applications including rolling predictions of water demand and hydraulic state, online detection of events such as pipe bursts, and data mining for identification of longer-term trends. This paper illustrates the advantage of the Water Wise platform in resolving operational decisions

Real-Time Hydraulic Modelling of a Water Distribution System in Singapore

This paper describes the implementation of a real-time hydraulic model of a water distribution system in Singapore. This on-line system is based on the Integration of real-time hydraulic data with hydraulic computer simulation models and statistical prediction tools. To facilitate this implementation, a network of wireless sensor nodes continuously sample hydraulic data such as pressure and flow rate, transmitting it to cloud-based servers for processing and archiving. Then, data streams from the sensor nodes are integrated into an on-line hydraulic modeling subsystem that is responsible for on-line estimation and prediction of the water distribution system's hydraulic state for a rolling planning horizon of 24 hours ahead. This online hydraulic model is one of the components of the WaterWiSe (Wierless Water Sentinel) platform which is an end-to-end integrated hardware and software system for monitoring, analyzing, and modeling urban water distribution systems in real-time.Singapore. National Research FoundationSingapore-MIT Alliance for Research and Technology. Center for Environmental Sensing and Modelin

Flexible Reconfiguration of Existing Urban Water Infrastructure Systems

This paper presents a practical methodology for the flexible reconfiguration of existing water distribution infrastructure, which is adaptive to the water utility constraints and facilitates in operational management for pressure and water loss control. The network topology is reconfigured into a star-like topology, where the center node is a connected subset of transmission mains, that provides connection to water sources, and the nodes are the subsystems that are connected to the sources through the center node. In the proposed approach, the system is first decomposed into the main and subsystems based on graph theory methods and then the network reconfiguration problem is approximated as a single-objective linear programming problem, which is efficiently solved using a standard solver. The performance and resiliency of the original and reconfigured systems are evaluated through direct and surrogate measures. The methodology is demonstrated using two large-scale water distribution systems, showing the flexibility of the proposed approach. The results highlight the benefits and disadvantages of network decentralization.MIT-Technion Fellowshi