Distributed Data Aggregation for Sparse Recovery in Wireless Sensor Networks

We consider the approximate sparse recovery problem in Wireless Sensor Networks (WSNs) using Compressed Sensing/Compressive Sampling (CS). The goal is to recover the n \mbox{-}dimensional data values by querying only $m \ll n$ sensors based on some linear projection of sensor readings. To solve this problem, a two-tiered sampling model is considered and a novel distributed compressive sparse sampling (DCSS) algorithm is proposed based on sparse binary CS measurement matrix. In the two-tiered sampling model, each sensor first samples the environment independently. Then the fusion center (FC), acting as a pseudo-sensor, samples the sensor network to select a subset of sensors ($m$ out of $n$) that directly respond to the FC for data recovery purpose. The sparse binary matrix is designed using unbalanced expander graph which achieves the state-of-the-art performance for CS schemes. This binary matrix can be interpreted as a sensor selection matrix-whose fairness is analyzed. Extensive experiments on both synthetic and real data set show that by querying only the minimum amount of $m$ sensors using the DCSS algorithm, the CS recovery accuracy can be as good as dense measurement matrices (e.g., Gaussian, Fourier Scrambles). We also show that the sparse binary measurement matrix works well on compressible data which has the closest recovery result to the known best k\mbox{-}term approximation. The recovery is robust against noisy measurements. The sparsity and binary properties of the measurement matrix contribute, to a great extent, the reduction of the in-network communication cost as well as the computational burden

Exploitation of Data Correlation and Performance Enhancement in Wireless Sensor Networks

With the combination of wireless communications and embedded system, lots of progress has been made in the area of wireless sensor networks (WSNs). The networks have already been widely deployed, due to their self-organization capacity and low-cost advantage. However, there are still some technical challenges needed to be addressed. In the thesis, three algorithms are proposed in improving network energy efficiency, detecting data fault and reducing data redundancy. The basic principle behind the proposed algorithms is correlation in the data collected by WSNs. The first sensor scheduling algorithm is based on the spatial correlation between neighbor sensor readings. Given the spatial correlation, sensor nodes are clustered into groups. At each time instance, only one node within each group works as group representative, namely, sensing and transmitting sensor data. Sensor nodes take turns to be group representative. Therefore, the energy consumed by other sensor nodes within the same group can be saved. Due to the continuous nature of the data to be collected, temporal and spatial correlation of sensor data has been exploited to detect the faulty data. By exploitation of temporal correlation, the normal range of upcoming sensor data can be predicted by the historical observations. Based on spatial correlation, weighted neighbor voting can be used to diagnose whether the value of sensor data is reliable. The status of the sensor data, normal or faulty, is decided by the combination of these two proposed detection procedures. Similar to the sensor scheduling algorithm, the recursive principal component analysis (RPCA) based algorithm has been studied to detect faulty data and aggregate redundant data by exploitation of spatial correlation as well. The R-PCA model is used to process the sensor data, with the help of squared prediction error (SPE) score and cumulative percentage formula. When SPE score of a collected datum is distinctly larger than that of normal data, faults can be detected. The data dimension is reduced according to the calculation result of cumulative percentage formula. All the algorithms are simulated in OPNET or MATLAB based on practical and synthetic datasets. Performances of the proposed algorithms are evaluated in each chapter

Sampling of graph signals via randomized local aggregations

Sampling of signals defined over the nodes of a graph is one of the crucial problems in graph signal processing. While in classical signal processing sampling is a well defined operation, when we consider a graph signal many new challenges arise and defining an efficient sampling strategy is not straightforward. Recently, several works have addressed this problem. The most common techniques select a subset of nodes to reconstruct the entire signal. However, such methods often require the knowledge of the signal support and the computation of the sparsity basis before sampling. Instead, in this paper we propose a new approach to this issue. We introduce a novel technique that combines localized sampling with compressed sensing. We first choose a subset of nodes and then, for each node of the subset, we compute random linear combinations of signal coefficients localized at the node itself and its neighborhood. The proposed method provides theoretical guarantees in terms of reconstruction and stability to noise for any graph and any orthonormal basis, even when the support is not known.Comment: IEEE Transactions on Signal and Information Processing over Networks, 201

ENDANGERED INFORMATION COMBINATION TECHNIQUE FOR WIRELESS SENSOR NETWORKS IN THE OCCURRENCE OF COLLUSION ATTACKS

Iterative filtering algorithms hold great promise for this sort of purpose. Because of limited computational power and sources, aggregation of understanding from multiple sensor nodes finished in the aggregating node is generally accomplished by simple way of example averaging. During this paper we show several existing iterative filtering algorithms, while considerably greater quality against collusion attacks in comparison with simple averaging methods, are nonetheless susceptive having a novel sophisticated collusion attack we introduce. However such aggregation is called highly vulnerable to node compromising attacks. Because the performance of small power processors dramatically improves, future aggregator nodes will have a way to performing modern-day data aggregation algorithms, thus making WSN less vulnerable. Thus, ascertaining standing of knowledge and standing of sensor nodes is important for WSN. Such algorithms concurrently aggregate data from multiple sources and provide trust assessment of people sources, usually in a kind of corresponding weight factors utilized on data supplied by each source. To handle this security issue, we advise an apparent difference for iterative filtering techniques by providing a preliminary approximation for such algorithms which makes them not just collusion robust, but in addition better and faster converging

AN EFFORT TO DETERMINE CREDIBILITY AND STATUS OF SENSOR NODES

Iterative filtering algorithms hold great promise for this type of purpose. Because of limited computational power and sources, aggregation of information from multiple sensor nodes done in the aggregating node is generally accomplished by simple methods for example averaging. Within this paper we show several existing iterative filtering algorithms, while considerably better quality against collusion attacks compared to simple averaging methods, are nonetheless susceptive to some novel sophisticated collusion attack we introduce. However such aggregation is proven to be highly susceptible to node compromising attacks. Because the performance of really low power processors dramatically improves, future aggregator nodes will manage to performing modern-day data aggregation algorithms, thus making WSN less vulnerable. Thus, ascertaining standing of data and status of sensor nodes is vital for WSN. Such algorithms concurrently aggregate data from multiple sources and supply trust assessment of those sources, usually in a kind of corresponding weight factors allotted to data supplied by each source. To deal with this security issue, we advise a noticeable difference for iterative filtering techniques by supplying a preliminary approximation for such algorithms causing them to be not just collusion robust, but additionally better and faster converging

DESIGN OF EFFICIENT IN-NETWORK DATA PROCESSING AND DISSEMINATION FOR VANETS

By providing vehicle-to-vehicle and vehicle-to-infrastructure wireless communications, vehicular ad hoc networks (VANETs), also known as the “networks on wheels”, can greatly enhance traffic safety, traffic efficiency and driving experience for intelligent transportation system (ITS). However, the unique features of VANETs, such as high mobility and uneven distribution of vehicular nodes, impose critical challenges of high efficiency and reliability for the implementation of VANETs. This dissertation is motivated by the great application potentials of VANETs in the design of efficient in-network data processing and dissemination. Considering the significance of message aggregation, data dissemination and data collection, this dissertation research targets at enhancing the traffic safety and traffic efficiency, as well as developing novel commercial applications, based on VANETs, following four aspects: 1) accurate and efficient message aggregation to detect on-road safety relevant events, 2) reliable data dissemination to reliably notify remote vehicles, 3) efficient and reliable spatial data collection from vehicular sensors, and 4) novel promising applications to exploit the commercial potentials of VANETs. Specifically, to enable cooperative detection of safety relevant events on the roads, the structure-less message aggregation (SLMA) scheme is proposed to improve communication efficiency and message accuracy. The scheme of relative position based message dissemination (RPB-MD) is proposed to reliably and efficiently disseminate messages to all intended vehicles in the zone-of-relevance in varying traffic density. Due to numerous vehicular sensor data available based on VANETs, the scheme of compressive sampling based data collection (CS-DC) is proposed to efficiently collect the spatial relevance data in a large scale, especially in the dense traffic. In addition, with novel and efficient solutions proposed for the application specific issues of data dissemination and data collection, several appealing value-added applications for VANETs are developed to exploit the commercial potentials of VANETs, namely general purpose automatic survey (GPAS), VANET-based ambient ad dissemination (VAAD) and VANET based vehicle performance monitoring and analysis (VehicleView). Thus, by improving the efficiency and reliability in in-network data processing and dissemination, including message aggregation, data dissemination and data collection, together with the development of novel promising applications, this dissertation will help push VANETs further to the stage of massive deployment

An Effective Wireless Sensor Network Routing Protocol Based on Particle Swarm Optimization Algorithm

Improving wireless communication and artificial intelligence technologies by using Internet of Things (Itoh) paradigm has been contributed in developing a wide range of different applications. However, the exponential growth of smart phones and Internet of Things (IoT) devices in wireless sensor networks (WSNs) is becoming an emerging challenge that adds some limitations on Quality of Service (QoS) requirements. End-to-end latency, energy consumption, and packet loss during transmission are the main QoS requirements that could be affected by increasing the number of IoT applications connected through WSNs. To address these limitations, an effective routing protocol needs to be designed for boosting the performance of WSNs and QoS metrics. In this paper, an optimization approach using Particle Swarm Optimization (PSO) algorithm is proposed to develop a multipath protocol, called a Particle Swarm Optimization Routing Protocol (MPSORP). The MPSORP is used for WSN-based IoT applications with a large volume of traffic loads and unfairness in network flow. For evaluating the developed protocol, an experiment is conducted using NS-2 simulator with different configurations and parameters. Furthermore, the performance of MPSORP is compared with AODV and DSDV routing protocols. The experimental results of this comparison demonstrated that the proposed approach achieves several advantages such as saving energy, low end-to-end delay, high packet delivery ratio, high throughput, and low normalization load.publishedVersio

Resilient networking in wireless sensor networks

This report deals with security in wireless sensor networks (WSNs), especially in network layer. Multiple secure routing protocols have been proposed in the literature. However, they often use the cryptography to secure routing functionalities. The cryptography alone is not enough to defend against multiple attacks due to the node compromise. Therefore, we need more algorithmic solutions. In this report, we focus on the behavior of routing protocols to determine which properties make them more resilient to attacks. Our aim is to find some answers to the following questions. Are there any existing protocols, not designed initially for security, but which already contain some inherently resilient properties against attacks under which some portion of the network nodes is compromised? If yes, which specific behaviors are making these protocols more resilient? We propose in this report an overview of security strategies for WSNs in general, including existing attacks and defensive measures. In this report we focus at the network layer in particular, and an analysis of the behavior of four particular routing protocols is provided to determine their inherent resiliency to insider attacks. The protocols considered are: Dynamic Source Routing (DSR), Gradient-Based Routing (GBR), Greedy Forwarding (GF) and Random Walk Routing (RWR)

A Combined Dual Leader and Relay Node Selection for Markov Cluster Based WSN Routing Protocol

The major challenge in Wireless Sensor Networks (WSNs) is to increase the node’s lifespan and decrease energy utilization. To avoid this issue, many Clustering Routing Protocols (CRPs) have been developed, where Cluster Head (CH) in each cluster accumulates the data from each other node and transfers it to the sink through Relay Nodes (RNs). But both CHs and RNs dissipate more energy to aggregate and transfer data. As a result, it is vital to choose the appropriate CHs and RNs concurrently to reduce energy utilization. Hence, this article proposes a Weighted Markov Clustering with Dual Leader and Relay node Selection based CRP (WMCL-DLRS-CRP) in WSNs. This protocol aims to lessen energy dissipation during inter- and intra-cluster communication. Initially, a Markov Clustering (MCL) algorithm is applied by the sink to create nodes into clusters based on a threshold distance. Then, a dual leader selection scheme is proposed to elect dual CHs in each cluster according to the node weighting factor that considers the node’s remaining energy, the distance between CHs and sink, the distance among all nodes, and abundance. Also, an RN selection scheme is proposed to choose the appropriate RNs based on a new Predicted Transmission Rate (PTR) factor. Moreover, the elected RNs transfer the data from the CHs to the sink, resulting in a tradeoff between the node’s energy utilization and lifetime. At last, extensive simulations illustrate that the WMCL-DLRS-CRP achieves better network performance compared to the existing protocols