ENERGY EFFICIENT DISTRIBUTED STEGANOGRAPHY FOR SECURE COMMUNICATION IN WIRELESS MULTIMEDIA SENSOR NETWORKS

A secure communication mechanism is necessary in the applications of Wireless Multimedia Sensor Networks (WMSNs), which is more vulnerable to security attacks due to the presence of multimedia data. Additionally, given the limited technological resources (in term of energy, computation, bandwidth, and storage) of sensor nodes, security and privacy policies have to be combined with energy-aware algorithms and distributed processing of multimedia contents in WMSNs. To solve these problems in this paper, an energy efficient distributed steganography scheme, which combines steganography technique with the concept of distributed computing, is proposed for secure communication in WMSNs. The simulation results show that the proposed method can achieve considerable energy efficiency while assuring the communication security simultaneously.

A QoS-Based Multichannel MAC Protocol for Two-Tiered Wireless Multimedia Sensor Networks

Rapid penetration of small customized wireless devices and enormous growth of wireless communication technologies has already set the stage for large-scale deployment of wireless sensor networks. Offering precise quality of service (QoS) for multimedia transmission over sensor networks has not received significant attention. However offering some better QoS for wireless multimedia over sensor networks raises significant challenges. In this paper, we propose an adaptive Cross-Layer multi-channel QoS-MAC protocol to support energy-efficient, high throughput, and reliable data transmission in Wireless Multimedia Sensor Network (WMSNs). Our proposed protocol use benefit of TDMA and CSMA/CA to adaptively assign channels and timeslots to active multimedia sensor nodes in clusters. Simulations show that the proposed system achieves the performance objectives of WMSNs with increased network throughput at the cost of a small control and energy overhead.

Enhanced Metaheuristics-Based Clustering Scheme for Wireless Multimedia Sensor Networks

Traditional Wireless Sensor Networks(WSNs)comprise of costeffective sensors that can send physical parameters of the target environment to an intended user.With the evolution of technology,multimedia sensor nodes have become the hot research topic since it can continue gathering multimedia content and scalar from the target domain.The existence of multimedia sensors,integrated with effective signal processing and multimedia source coding approaches,has led to the increased application of Wireless Multimedia Sensor Network(WMSN).This sort of network has the potential to capture,transmit,and receive multimedia content.Since energy is a major source in WMSN,novel clustering approaches are essential to deal with adaptive topologies of WMSN and prolonged network lifetime.With this motivation,the current study develops an Enhanced Spider Monkey Optimization-based Energy-Aware Clustering Scheme(ESMO-EACS)for WMSN.The proposed ESMO-EACS model derives ESMO algorithm by incorporating the concepts of SMO algorithm and quantum computing.The proposed ESMO-EACS model involves the design of fitness functions using distinct input parameters for effective construction of clusters.A comprehensive experimental analysis was conducted to validate the effectiveness of the proposed ESMO-EACS technique in terms of different performance measures.The simulation outcome established the superiority of the proposed ESMO-EACS technique to other methods under various measures.

A time domain multiple-CFOs and CIRs estimation algorithm over wireless multimedia sensor networks

Channel parameters estimation in an orthogonal for the receiver station is a multi-dimensional （MD） frequency division multiple access （OFDMA） system optimization problem, because every user node has a separate local oscillator and every transmitter to receiver link has individual carrier frequency offset （CFO） and channel impulse response （CIR） parameters. In order to reduce the computational complexity for MD optimization, a time domain CFOs and CIRs estimation algorithm over the OFDMA based wireless multimedia sensor networks （WMSN） is proposed in this paper. In this algorithm, the receiver station can decouple the signal from every node by correlation based on specially designed training sequences, so that the MD optimization problem is simplified to an 1-D optimal problem. It is proved that the multiple CFOs can be identified from the correlation result using the phase shift of the consecutive training se- quences. Based on the CFOs estimation result, the CIRs can then he estimated according to the minimum mean square error （MMSE） criterion. The theoretic analysis and simulation results show that the proposed algorithm can effectively decouple the signal from different user nodes and the bit error rate （BER） per- formance curves are close to the ideal estimation when the user number is not large.

Clustering in Wireless Multimedia Sensor Networks Using Spectral Graph Partitioning

Wireless multimedia sensor network (WMSN) consists of sensors that can monitor multimedia data from its surrounding, such as capturing image, video and audio. To transmit multimedia information, large energy is required which decreases the lifetime of the network. In this paper we present a clustering approach based on spectral graph partitioning (SGP) for WMSN that increases the lifetime of the network. The efficient strategies for cluster head selection and rotation are also proposed.

Clustering in Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs) are comprised of small embedded audio/video motes capable of extracting the surrounding environmental information, locally processing it and then wirelessly transmitting it to sink/base station. Multimedia data such as image, audio and video is larger in volume than scalar data such as temperature, pressure and humidity. Thus to transmit multimedia information, more energy is required which reduces the lifetime of the network. Limitation of battery energy is a crucial problem in WMSN that needs to be addressed to prolong the lifetime of the network. In this paper we present a clustering approach based on Spectral Graph Partitioning (SGP) for WMSN that increases the lifetime of the network. The efficient strategies for cluster head selection and rotation are also proposed as part of clustering approach. Simulation results show that our strategy is better than existing strategies.

A Sensor Awakening Algorithm for Wireless Multimedia Sensor Networks Three Dimensional Target Tracking

For node awakening in wireless multi-sensor networks, an algorithm is put forward for three dimensional tar- get tracking. To monitor target dynamically in three dimensional area by controlling nodes, we constract vir- tual force between moving target and the current sense node depending on the virtual potential method, then select the next sense node with information gain function, so that when target randomly move in the specific three dimensional area, the maximum sensing ratio of motion trajectory is get with few nodes. The proposed algorithm is verified from the simulations.

Queuing Management in Wireless Sensor Networks for QoS Measurement

Data transmission in multimedia WSNs are required high bandwidth and reliable transfer because of large amount of data size. However, some applications of WSNs are required high quality. In this context, main factor in quality of services (QoS) metrics in WSNs becomes longevity of the network and high quality. In sensor nodes, choosing relevant transceiver and microcontroller components plays important role in assembling sensor devices, in which data controls should be designed so that packet loss is minimized. Available QoS metrics based on queuing/buffer management in wired and other wireless networks don’t applicable in WSNs because of its unique characteristics. In this paper the simplest model of QoS model-bufferless system were proposed. In the proposed model, measurement of the probability of blocking of the arrival packets was suggested by using queuing theory in order to increase QoS. Given probability of blocking (PB) illustrates clear picture how system specification should be chosen so that blocking state would be minimized.

Energy Efficient and QoS Aware Framework for Video Transmission over Wireless Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs), is a network of sensors, which are limited in terms of memory, computing, bandwidth, and battery lifetime. Multimedia transmission over WSN requires certain QoS guarantees such as huge amount of bandwidth, strict delay and lower loss ratio that makes transmitting multimedia is a complicated task. However, adopting cross-layer approach in WMSNs improves quality of service of WSN under different environmental conditions. In this work, an energy efficient and QoS aware framework for transmitting multimedia content over WSN (EQWSN) is presented, where packet, queue and path scheduling were introduced. It adapts the application layer parameter of video encoder to current wireless channel state, and drops less important packets in case of network congestion according to packet type. Finally, the path scheduling differentiates packets types/priority and route them through different paths with different QoS considering network lifetime. Simulation results show that the new scheme EQWSN transmits video quality with QoS guarantees in addition to prolonging network lifetime.

基于蝗虫算法的配电通信WMSNs多路径QoS路由优化模型研究

为提高配电通信网络的生命周期,降低网络能耗和均衡化WMSNs多路径QoS路由网络负荷,提出一种基于配电通信网的蝗虫算法优化WMSNs多路径QoS路由算法研究。选择WMSNs多路径QoS路由路径最短和能量最低为目标函数。研究结果表明,与改进算法和经典算法相比,基于GOA的WMSNs多路径QoS路由算法网络能耗最低、死亡节点数最少,效果很好,可以延长死亡节点产生的时间,有效提高整个WMSNs多路径QoS路由网络的生存寿命。

Node correlation clustering algorithm for wireless multimedia sensor networks based on overlapped FoVs

In this paper, a clustering algorithm is proposed based on the high correlation among the overlapped field of views for the wireless multimedia sensor networks. Firstly, by calculating the area of the overlapped field of views （FoVs） based on the gird method, node correlations have been obtained. Then, the algorithm utilizes the node correlations to partition the network region in which there are high correlation multimedia sensor nodes. Meanwhile, in order to minimize the energy consumption for transmitting images, the strategy of the cluster heads election is proposed based on the cost estimation, which consists of signal strength and residual energy as well as the node correlation. Simulation results show that the proposed algorithm can balance the energy consumption and extend the network lifetime effectively.

Novel congestion control approach in wireless multimedia sensor networks

Data generated in wireless multimedia sensor networks （WMSNs） may have different importance and it has been claimed that the network exert more efforts in servicing applications carrying more important information. Nevertheless, importance of packets cannot generally be accurately represented by a static priority value. This article presents a dynamic priority based congestion control （DPCC） approach that makes two major innovations in WMSNs. First, DPCC employs dynamic priority to represent packet importance. Second, it prioritizes the local traffic of motes near the base station when WMSN is highly congested. Simulation results confirm the superior performance of the proposed approach with respect to energy efficiency, loss probability and latency as well.

基于方差的WMSN图像非均匀分块自适应压缩算法

针对无线多媒体传感器网络数据量较大和储存能力有限等问题,提出了基于方差的图像非均匀分块自适应压缩算法。在传统的压缩方法中,均匀分块的稀疏变换对图像信号进行压缩,会带来图像重构的块状效应,而且无法有效地分离出重要区域或者背景区域。给出一种基于方差的图像非均匀分块自适应压缩算法,以图像方差值作为块大小分割依据,利用四叉树算法进行图像块大小的划分。并将分块大小结果分成快速变化块、过度块和缓慢变化块3类,适时做不同程度的压缩。实验结果表明:本文所提出的算法在图像重构质量方面优于传统的均匀分块压缩方法。

Image compression scheme based on PCA for wireless multimedia sensor networks

In combination of the characteristic of the network architecture of wireless multimedia sensor networks （WMSNs）, a distributed multi-node cooperative network （DMCN） model is designed by using the concept of in-network processing to improve their energy, memory and computational power. To balance the energy consumption of the network, according to roles division, camera nodes and common nodes are cooperated to accomplish the workload of image acquisition, compression and transmission. Camera nodes gather images and send blocking images to the common nodes in cluster. Common nodes adaptively compress the partitioned images by using a noise-tolerant distributed image compression （NDIC） algorithm based on principal component analysis （PCA） called NDIC-PCA algorithm and send the compressed data to the cluster head node. Then, the cluster head node sends the compressed image data to the station. Simulation results demonstrate that, DCNM can effectively balance the energy consumption of network and largely extend the network lifecycle. In addition, compared with previous algorithms, the proposed NDIC-PCA algorithm achieves higher peak signal to noise ratio without decreasing compression ratio.

Multi-level cross-layer protocol for end-to-end delay provisioning in wireless multimedia sensor networks

Rapid developments in information and communication technology in recent years have posed a significant challenge in wireless multimedia sensor networks(WMSNs).End-to-end delay and reliability are the critical issues in multimedia applications of sensor networks.In this paper we provide a new cross-layer approach for provisioning the end-to-end delay of the network at a desirable level of the packet delivery ratio(PDR),used here as a measure of network reliability.In the proposed multi-level cross-layer(MLCL)protocol,the number of hops away from the sink is used to set a level for each node.A packet is routed through the path with the minimum hop count to the sink using this level setting.The proposed protocol uses cross-layer properties between the network and medium access control(MAC)layers to estimate the minimum delay,with which a node can deliver a packet to the sink.When a node wants to send a packet,the MLCL protocol compares this minimum delay with the time to live(TTL)of a packet.If the TTL of the packet is higher than the minimum delay,the node sends the packet through the path with the minimum delay;otherwise,the node drops the packet as the node cannot deliver it to the sink within the TTL duration.This packet dropping improves network performance because the node can send a useful packet instead of an unusable packet.The results show a superior performance in terms of end-to-end delay and reliability for the proposed protocol compared to state-of-the-art protocols.

Performance Improvement of Wireless Multimedia Sensor Networks Using MIMO and Compressive Sensing

Wireless Multimedia Sensor Networks(WMSN)are designed to transmit audio and video streams,still images,and scalar data.Multimedia transmission over wireless sensor networks has many applications,such as video surveillance,object tracking,telemedicine,theft control systems,and traffic monitoring.Researchers face many challenges,such as higher data rates,lower energy consumption,reliability,signal detection and estimation,uncertainty in network topology,quality of service(QoS),and security-and privacy-related issues to accomplish various applications of WMSN.This paper presents multiple input multiple output(MIMO)along with compressive sensing(CS)properties to improve system performance in terms of energy consumption and QoS in deep fade environments.The CS theory model has been proposed to reduce energy consumption by taking fewer measurements of the original signal or information and reconstructing it with acceptable image quality at the receiver side.The transmission and processing energy can be reduced by transmitting fewer measurements from the sensor side itself.The MIMO model and CS algorithm have been simulated,and results show that CS performs well on images.

无线多媒体传感器网络QoS路由算法研究

由于廉价的CMOS摄像头、麦克风的出现,以及对含有丰富信息的图像、视频和音频信息需求导致了无线多媒体传感器网络(WMSN)的出现。WMSN具有资源有限、可变的信道容量、数据高度冗余等特点,使得WMSN的QoS路由具有极大的挑战性。提出了一种基于Mesh结构的WMSN,并在该结构体系下,提出了一种基于蚁群算法的QoS路由算法。实验研究表明,蚁群算法具有不依赖全局信息的优点,具有应用于WMSN的前景。实验同时表明,决定蚁群算法收敛速度以及会影响传感器网络性能的一些关键参数较难确定,需要进一步研究。

无线传感器网络中间件技术

目前,面向应用的无线传感器网络普遍缺乏统一开放的软件体系架构和高效的开发接口,因而阻碍了其进一步发展和应用。针对无线传感器网络特点,全面介绍无线传感器网络中间件软件的概念、设计需求与关键技术,并在此基础上分析其体系结构。同时,提出无线多媒体传感器网络中间件的概念,并构建一种基于Agent的无线多媒体传感器网络中间件体系。

一种面向三维感知的无线多媒体传感器网络覆盖增强算法

覆盖作为无线传感器网络中的基础问题直接反映了网络感知服务质量.本文在分析现有无线多媒体传感器网络覆盖增强算法的基础上,构建节点三维感知模型,提出面向三维感知的多媒体传感器网络覆盖增强算法(Three-Dimensional Perception Based Coverage-Enhancing Algorithm,TDPCA).该算法将节点主感知方向划分为仰俯角和偏向角,并根据节点自身位置及监测区域计算并调整各节点最佳仰俯角,在此基础上基于粒子群优化调整节点偏向角,从而有效减少节点感知重叠区及感知盲区,最终实现监测场景的区域覆盖增强.仿真实验表明:对比已有的覆盖增强算法,TDPCA可有效降低除节点感知重叠区和盲区,最终实现网络的高效覆盖.

无线多媒体传感器网络视频编码研究

在资源受限的无线多媒体传感器网络中存在大量的视频数据需要处理和传输。为充分地利用这些有限的资源,需要设计一个能够综合考虑能量消耗和压缩率、图像质量之间平衡的视频编码方案。对无线多媒体传感器网络中视频编码技术的发展现状、面临的挑战和设计目标进行了讨论。对无线多媒体传感器网络视频编码现有的解决方案和理论研究成果进行探讨,分别从个体信源编码和分布式信源编码两方面进行分类探索。最后,对个体信源编码存在的一些问题进行讨论,并指出了未来研究的方向。