Abstract
Big data through cloud computing is an excellent way to offload significant amounts of computation and data from both data centers and terminal devices, due to its flexibility, scalability, and significant economic savings. However, cloud computing may not be suitable for all applications such as WSN (Wireless Sensor Network) for its high requirement on real time latency and response and geographically distributed and mobility support. For WSN, targets areas are close to the physical world, while cloud moves part of data storage and computation toward the edge of the network. This special issue aims at providing researchers and practitioners from the academia, industry, and government an opportunity to reflect upon these new developments of recent advances for big data in ubiquitous Wireless Sensor Networks and focus on the computation and storage, data analysis and mining, and distributed algorithms for data and computation placement, guaranteeing a global standard of quality and system integrity in Wireless Sensor Networks. We have accepted a few papers that address the state of the art and the future directions of these research and application areas for big data in ubiquitous Wireless Sensor Networks in this issue.
The paper “Sparse signal recovery by stepwise subspace pursuit in compressed sensing” describes an algorithm named stepwise subspace pursuit (SSP) for sparse signal recovery. This approach eliminates useless information from the candidate through threshold processing at first and then recovers the signal through the largest correlation coefficients. Experiments demonstrate that SSP significantly outperforms conventional techniques in recovering sparse signals.
The paper “Coverage optimization algorithm based on sampling for 3D underwater sensor networks” addresses the problem of maximizing the sensor field coverage for specific number of sensors while minimizing the distance traveled by the sensor nodes. Movement task as an optimization problem is defined to involve the adjustment of sensor node positions and coverage optimization algorithm based on sampling to enhance the coverage of 3D underwater sensor networks. A quadratic programming mathematical model is established to optimize the line segment coverage according to the intersection between sensing circles and line segments while minimizing the moving distance of the nodes.
The paper “A coding and postprocessing framework of multiview distributed video for wireless video sensor networks” proposes a new multiview video coding and postprocessing framework for multiview videos. The subsequent decoded videos of postprocessing simulation prove that the proposed postprocessing scheme can provide an additional improvement to the decoded video sequences.
The paper “Hybrid ant algorithm based query processing with multiagents in sensor networks” investigates query processing problem in resource-constrained Wireless Sensor Networks with two-tier architecture and multiple query agents, where multiple nodes of query agents are configured in the networks and corresponding source cluster-heads send collected events to only one optimum query agent. To reduce the energy consumption and shorten the delivery delay, an efficient query processing algorithm inspired by swarm intelligence of ants is introduced.
The paper “A novel image mosaicking algorithm for wireless multimedia sensor networks” focuses on how to take advantage of the cooperation among sensor nodes to obtain the panoramic information of scenic spots. And an image mosaic algorithm based on phase correlation and weighted average (IMBPW) is proposed. The IMBPW algorithm uses the phase correlation based on Fourier transform to achieve registration of translation, rotation, and scaling images; adaptive weighted average algorithm is proposed to do the image fusion.
The paper “Fast endmember extraction for massive hyperspectral sensor data on GPUs” aims at proposing a method of parallel optimization for the well-known N-FINDR algorithm on graphics processing units (NFINDR-GPU) which is proposed to realize fast endmember extraction for massive hyperspectral sensor data. Experimental results show the effectiveness of NFINDR-GPU.
The paper “A sociability-based spray and forward scheme for opportunistic network” studies the nodes moving patterns when designing data transmission strategy. Based on the analysis of node moving characteristics in opportunistic social networks, social rang and social frequency are introduced and sociability-based Spray and Forward (SSF) scheme is proposed. Simulation results show that SSF can effectively improve data delivery ratio and reduce latency.
The paper “A new metric for modeling the uneven sleeping problem in coordinated sensor node scheduling” analyses the uneven sleeping problem (USP) happening in coordinated node scheduling in Wireless Sensor Networks. By analysing key factors leading to USP, a new metric is designed to measure and evaluate USP.
The paper “Uncertainty-aware sensor deployment strategy in mixed wireless sensor networks” studies the challenging problem of sensor deployment in a mixed sensor network where the mobile and static nodes work collaboratively to perform deployment optimization task. Gaussian white noise in environment is considered and a centralized algorithm is presented by using detection model based on false alarm and moves the mobile nodes based on bipartite graph matching.
The paper “Research on migration strategy of mobile agent in wireless sensor networks” investigates the migration schemes for mobile agents, determines core factors of migration strategy, and proposes SMLA and DMLA algorithms; advantages and disadvantages of the algorithms are evaluated by simulations.
The paper “An approach based on chain key predistribution against Sybil attack in wireless sensor networks” presents a chain key predistribution based approach against Sybil attack. Lightweight hash function and node-to-node chain key based authentication and exchange (CK-AE) protocol are proposed. Results show that this approach can not only enhance the ability of resilience to Sybil attack, but also reduce the communication overhead significantly at the cost of a certain amount of computational overhead.
The paper “A new scheme based on pixel-intense motion block algorithm for residual distributed video coding” proposes a new approach of residual coding combined with IMB (intense motion block) extraction algorithm with Low Density Parity Check (LDPC) and Baum-Welch iterative decoding algorithm. Experimental results show that the proposed scheme achieves better rate-distortion performance compared to traditional DVC and RDVC scheme.
The paper “Multisensor data fusion for water quality evaluation using Dempster-Shafer evidence theory” proposed a multisensor data fusion approach for water quality evaluation using Dempster-Shafer evidence theory. Each sensor measurement is considered as a piece of evidence. Based on quality parameters measured by sensor node, evidence from each sensor is given a reliability discounting and then combined with others by D-S rule. According to the decision rule, the class of water quality can be determined.
The paper “Resilient multipath routing mechanism based on clustering with intrusion tolerance” introduces the key management scheme after analyzing the security threats of LEACH protocol. Several related mechanisms to protect the communication among the sensor nodes and the confidentiality of the data transmission are adopted. Also, mixed multipath mechanism among the clusters is used to improve the security of the network and strengthen the intrusion tolerance.
The paper “Data deduplication in wireless multimedia monitoring network” applies data deduplication technology in Wireless Multimedia Monitoring Network. It eliminated redundant data from raw data to exploit network bandwidth efficiently. Moreover, a chunking algorithm with low computation complexity is presented.
The paper “Research and design of an airfield runway FOD detection system based on WSN” analyses Foreign object debris (FOD) surveillance system and introduces a designed method of airport runway FOD detection system based on WSN, and function of various image acquisition sensors is analyzed.
The paper “A novel wireless sensor networks structure based on the SDN” addresses the SDN (Software Defined Network) technology based on OpenFlow, and a new solution for WSNS in accordance with the OpenFlow technology is proposed.
The Paper “Discovering human presence activities with smartphones using nonintrusive Wi-Fi sniffer sensors: the big data prospective” describes an optimized Wi-Fi channel detection and selection method to switch between the best channels automatically to aggregate the Wi-Fi messages. Efficiency is demonstrated by experiment deploying in real-world office environment.