基于最优阶估计与分布式分簇的传感器网络数据压缩方法研究

在无线传感器网络的诸多应用中,被监测区域发生异常情况的概率通常较小,正常情况下,同一传感器节点在前后连续时刻所采集的数据具有时间相关性,处于相邻区域的不同传感器节点在同一时刻所采集的数据具有空间相关性,发送存在时间、空间冗余的数据至基站必将耗费节点大量的能量。该文提出了基于最优阶估计和分布式分簇的传感器网络数据压缩方法,利用节点采集数据的时空相关性,基于最优阶估计在基站处建立相关系数,经分布式分簇,节点仅需传送少量数据,基站根据时空相关性恢复原始数据。仿真结果表明应用该算法,可以有效减少传感器网络中冗余数据传输量和节点能耗,进而延长系统寿命。     

传感器网络中一种基于估计代价的数据聚合树生成算法

无线传感器网络是一种全新的技术,能够广泛应用于恶劣环境和军事领域.传感器网络在数据收集中,为减少冗余数据的传输耗能,降低延迟,需要采用数据聚合技术.本文采用定向传输方式,在消息路由机制基础上提出了一种基于估计代价的数据聚合树生成算法.该算法主要思想在于将节点能耗、传输距离与聚合收益三方面作为估计代价,优化聚合路径,实现数据聚合在能量与时延上的折中.     

基于蚁群算法的无线传感器网络数据聚合路由算法

传感器网络为减少冗余数据的传输耗能。降低延迟,需要在路由过程中采用数据聚合技术。文中采用定向传输方式,在消息路由机制基础上提出了一种基于蚁群算法的数据聚合路由算法。该算法主要思想在于将节点能耗、传输距离与聚合收益3方面作为启发因子,通过一组称为“蚂蚁”的人工代理寻找到达汇聚节点的最优路径。该算法利用蚁群算法的正反馈效应来达到数据汇集的目的,不需要网络节点维护全局信息,因此是一种实现数据聚合在能量与时延上折中的分布式路由算法。理论分析和仿真结果说明了新算法的有效性。     

基于概率模型的无线传感器网络优化覆盖算法

为了更好地解决无线传感器网络在覆盖过程中出现大量冗余信息及节点能量消耗不均衡等现象,提出了一种节点能量均衡的最优覆盖算法。该算法利用监测区域内传感器节点与目标节点的从属关系建立网络模型,给出传感器节点与目标节点之间的从属关系;通过从属关系和概率理论,求解传感器节点对目标节点的覆盖期望值,然后计算出覆盖监测区域所需最少传感器节点数量。实验结果表明,该算法不仅可以使用最少传感器节点完成对监测区域的有效覆盖,而且抵制了冗余信息数据的产生,提高了网络生存周期。     

无线传感器中的数据收集与聚合

由于无线传感器网络受节点能量限制,而且大部分能量都消耗在数据传输上,所以设计能量高效的数据聚合算法,对于延长网络生命周期具有重要意义。文章首先详细介绍了无线传感器数据聚合的研究背景,然后分别阐述了基于网络结构的数据聚合算法,最后分析了几种改进的数据聚合算法。     

传感器网络中一种基于一元线性回归模型的空时数据压缩算法

针对传感器网络中节点采样数据的空间和时间冗余特点以及节能要求,该文提出了一种基于一元线性回归模型的空时数据压缩算法ODLRST。ODLRST先在每个节点内进行消除时间冗余的数据压缩,再在节点汇集处对来自不同节点的数据消除空间冗余以进一步压缩数据。仿真实验证明,ODLRST能够极大地减少节点发送的数据量和网络中的通信流量,节省并平衡网络中的能量消耗。     

基于网格的无线传感器网络非均匀分簇算法

在无线传感器网络中,首先要考虑的是如何解决能耗问题.针对无线传感器网络现有算法存在的节点能耗不均匀及节点部署密集造成的数据冗余和能量浪费,提出了一种节能路由算法UECG.通过设定虚拟网格以及非均匀分簇来实现网络能量的均衡消耗.仿真结果表明,与LEACH协议及其改进协议EEUC相比,UECG算法能够有效减少冗余数据,平衡簇群间的能量消耗,达到延长网络寿命的目的.     

用于区域监测的无线传感器网络数据去冗余研究

提高能量效率是无线传感器网络研究的关键技术之一.通过分析无线传感器网络监测区域的信号空时频域动态特征,给出了基于信号空间频率带宽的无线传感器网路传感器节点的放置算法.提出基于空时域频率动态带宽的数据去空时冗余算法和相对应的路由策略.该算法有效地去除了数据的空时冗余,节省了网络的通信能量.     

无线传感器网络中基于序列相关性的数据压缩算法

无线传感器网络(WSN)中传输的数据具有相关性和冗余性。如何有效降低网络中的数据量,延长网络生命周期,始终是WSN的研究热点之一。该文基于WSN中数据序列的相关性,提出一种两步数据压缩算法(TSC-SC)。网络中的簇首和簇内节点执行各自的压缩算法:簇首首先执行相关性分组算法,将数据分组,减少簇内节点的计算量以及消除簇内数据的空间相关性;簇内节点对多属性数据分类压缩,并将压缩参数传至簇首,簇首解压后再次进行分类压缩,进一步消除数据相关性,减少节点数据冗余度,降低通信能耗。为实现对压缩算法的综合性能评价,考虑基本的压缩要求和算法的计算能耗,提出了基于能量判别的算法评估模型(NCER)。仿真结果表明TSC-SC算法可以有效降低压缩比和压缩误差,充分减少数据传输量和网络的通信能耗,利用NCER指标能够直观地评价算法的性能。     

基于空间相关性的事件驱动无线传感器网络分簇算法

分簇算法是传感器网络中减少能量消耗的一种关键技术,它能够增强网络的扩展性和延长网络的生存时间。针对传感器节点数据的空间相关性,该文提出了一种新的基于空间相关性的事件驱动传感器网络分簇算法。算法根据用户要求的误差门限及结合节点数据的空间相关性马尔可夫模型,将事件感知区域划分成虚拟极坐标等价层。每个等价层选取层内当前剩余能量最大的节点作为簇头,网络通过移动代理收集簇头感知信息,该方法减少了传输数据量,有效节省了网络能量。     

Deterministic binary matrix based compressive data aggregation in big data WSNs

In big data wireless sensor networks, the volume of data sharply increases at an unprecedented rate and the dense deployment of sensor nodes will lead to high spatial-temporal correlation and redundancy of sensors’ readings. Compressive data aggregation may be an indispensable way to eliminate the redundancy. However, the existing compressive data aggregation requires a large number of sensor nodes to take part in each measurement, which may cause heavy load in data transmission. To solve this problem, in this paper, we propose a new compressive data aggregation scheme based on compressive sensing. We apply the deterministic binary matrix based on low density parity check codes as measurement matrix. Each row of the measurement matrix represents a projection process. Owing to the sparsity characteristics of the matrix, only the nodes whose corresponding elements in the matrix are non-zero take part in each projection. Each projection can form an aggregation tree with minimum energy consumption. After all the measurements are collected, the sink node can recover original readings precisely. Simulation results show that our algorithm can efficiently reduce the number of the transmitted packets and the energy consumption of the whole network while reconstructing the original readings accurately.     

Secure data aggregation in wireless sensor networks using homomorphic encryption

In a Wireless Sensor Network (WSN), aggregation exploits the correlation between spatially and temporally proximate sensor data to reduce the total data volume to be transmitted to the sink. Mobile agents (MAs) fit into this paradigm, and data can be aggregated and collected by an MA from different sensor nodes using context specific codes. The MA-based data collection suffers due to large size of a typical WSN and is prone to security problems. In this article, homomorphic encryption in a clustered WSN has been proposed for secure and efficient data collection using MAs. The nodes keep encrypted data that are given to an MA for data aggregation tasks. The MA performs all the data aggregation operations upon encrypted data as it migrates between nodes in a tree-like structure in which the nodes are leafs and the cluster head is the root of the tree. It returns and deposits the encrypted aggregated data to the cluster head after traversing through all the intra cluster nodes over a shortest path route. The homomorphic encryption and aggregation processing in encrypted domain makes the data collection process secure. Simulation results confirm the effectiveness of the proposed secure data aggregation mechanism. In addition to security, MA-based mechanism leads to lesser delay and bandwidth requirements.     

Adaptive data aggregation with probabilistic routing in wireless sensor networks

Periodical extraction of raw sensor readings is one of the most representative and comprehensive applications in Wireless sensor networks. In order to reduce the data redundancy and the communication load, in-network data aggregation is usually applied to merge the packets during the routing process. Aggregation protocols with deterministic routing pre-construct the stationary structure to perform data aggregation. However, the overhead of construction and maintenance always outweighs the benefits of data aggregation under dynamic scenarios. This paper proposes an Adaptive Data Aggregation protocol with Probabilistic Routing for the periodical data collection events. The main idea is to encourage the nodes to use an optimal routing structure for data aggregation with certain probability. The optimal routing structure is defined as a Multi-Objective Steiner Tree, which can be explored and exploited by the routing scheme based on the Ant Colony Optimization and Genetic Algorithm hybrid approach. The probabilistic routing decision ensures the adaptability for some topology transformations. Moreover, by using the prediction model based on the sliding window for future arriving packets, the adaptive timing policy can reduce the transmission delay and can enhance the aggregation probability. Therefore, the packet transmission converges from both spatial and temporal aspects for the data aggregation. Finally, the theoretical analysis and the simulation results validate the feasibility and the high efficiency of the novel protocol when compared with other existing approaches.     

Data Aggregation in Wireless Sensor Networks: Previous Research,Current Status and Future Directions

Wireless sensor networks (WSNs) consist of large number of small sized sensor nodes, whose main task is to sense the desired phenomena in a particular region of interest. These networks have large number of applications such as habitat monitoring, disaster management, security and military etc. Sensor nodes are very small in size and have limited processing capability as these nodes have very low battery power. WSNs are also prone to failure, due to low battery power constraint. Data aggregation is an energy efficient technique in WSNs. Due to high node density in sensor networks same data is sensed by many nodes, which results in redundancy. This redundancy can be eliminated by using data aggregation approach while routing packets from source nodes to base station. Researchers still face trouble to select an efficient and appropriate data aggregation technique from the existing literature of WSNs. This research work depicts a broad methodical literature analysis of data aggregation in the area of WSNs in specific. In this survey, standard methodical literature analysis technique is used based on a complete collection of 123 research papers out of large collection of 932 research papers published in 20 foremost workshops, symposiums, conferences and 17 prominent journals. The current status of data aggregation in WSNs is distributed into various categories. Methodical analysis of data aggregation in WSNs is presented which includes techniques, tools, methodology and challenges in data aggregation. The literature covered fifteen types of data aggregation techniques in WSNs. Detailed analysis of this research work will help researchers to find the important characteristics of data aggregation techniques and will also help to select the most suitable technique for data aggregation. Research issues and future research directions have also been suggested in this research literature.     

Spatial and Temporal Multi-Aggregation for State-Based Sensor Data in Wireless Sensor Networks

Sensor nodes are thrown to remote environments for deployment and constitute a multi-hop sensor network over a wide range of area. Users hardly have global information on the distribution of sensor nodes. Hence, when users request state-based sensor readings such as temperature and humidity in an arbitrary area, networks may suffer unpredictable heavy traffic. This problem needs data aggregation to comply with user requirements and manage overlapped aggregation trees of multiple users efficiently. In this paper, spatial and temporal multiple aggregation (STMA) is proposed to minimize energy consumption and traffic load when a single or multiple users gather state-based sensor data from varions subareas through multi-hop paths. Spatial aggregation builds the aggregation tree with an optimal intermediary between a target area and a sink. The broadcast nature of wireless communication is exploited to build the aggregation tree in the confined area. Temporal aggregation uses the interval so that users obtain an appropriate amount of data they need without suffering excess traffic. The performance of STMA is evaluated in terras of energy consumption and area-to-sink delay in the simulation based on real parameters of Berkeley's MICA motes.     

一种面向智能电网数据采集的传感器聚合布局构造算法

智能电网中分布着大量的无线传感器用于监测智能电网设备和用户的运营状态信息,原始监测数据都采集到数据处理中心会给数据采集通信网络带来极大的数据流量压力。采用在数据采集过程中进行数据聚合的策略,将极大地缩减数据流量,降低通信网络的开销。因此聚合节点的选择以及聚合拓扑的构造成为智能电网数据采集的关键问题。该文提出一种基于层次聚类的异步分布式聚合布局构造算法。该算法首先按照层次聚类把所有节点按照距离的远近聚合构造出一棵采集树。随后计算出最佳分组数,按照该分组数进行分组。然后按照异步分布式策略进行最佳聚合节点的选择以及最佳传输拓扑的构造。仿真实验表明,该算法可以快速找到具有最小开销的数据聚合方式,提高智能电网数据采集网络的效率。     

Two Tier Cluster Based Data Aggregation (TTCDA) for Efficient Bandwidth Utilization in Wireless Sensor Network

Wireless Sensor Networks are often used for monitoring and control applications where sensor nodes collect data and send it to the sink. Direct transmission of data packets to the sink from nodes in the network causes increased communication costs in terms of energy, network lifetime and bandwidth utilization. In this context, this paper proposes Two Tier Cluster-based Data Aggregation (TTCDA) algorithm for the randomly distributed nodes in the network to minimize computation and communication cost. The TTCDA effectively considers the packet and data aggregation using additive and divisible aggregation functions at cluster head and sink. The aggregation functions are applied according to spatial and temporal correlation of packets and data generated by each node. It also prevents transmission of redundant data by improving energy consumption and bandwidth utilization as compared with state-of-the-art solution. The performance of the algorithm is validated using examples and simulations. Also, it is seen that packet aggregation in TTCDA is better for the bandwidth utilization as it reduces average energy consumption by 3.13 % as compared to data aggregation.     

SCT Based Adaptive Data Aggregation for Wireless Sensor Networks

Communication overhead is a major concern in wireless sensor networks because of inherent behavior of resource constrained sensors. To degrade the communication overhead, a technique called data aggregation is employed. The data aggregation results are used to make crucial decisions. Certain applications apply approximate data aggregation in order to reduce communication overhead and energy levels. Specifically, we propose a technique called semantic correlation tree, which divides a sensor network into ring-like structure. Each ring in sensor network is divided into sectors, and each sector consists of collection of sensor nodes. For each sector, there will be a sector head that is aggregator node, the aggregation will be performed at sector head and determines data association on each sector head to approximate data on sink node. We propose a doorway algorithm to approximate the sensor node readings in sector head instead of sending all sensed data. The main idea of doorway algorithm is to reduce the congestion and also the communication cost among sensor nodes and sector head. This novel approach will avoid congestion by controlling the size of the queue and marking packets. Specifically, we propose a local estimation model to generate a new sensor reading from historic data. The sensor node sends each one of its parameter to sector head, instead of raw data. The doorway algorithm is utilized to approximate data with minimum and maximum bound value. This novel approach, aggregate the data approximately and efficiently with limited energy. The results demonstrate accuracy and efficiency improvement in data aggregation.     

基于聚类模型预测的无线传感网自适应采样技术研究

该文利用无线传感网(WSNs)的数据空间相关性,提出一种基于数据梯度的聚类机制,聚类内簇头节点维护簇成员节点的数据时间域自回归(AR)预测模型,在聚类内范围实施基于预测模型的采样频率自适应算法。通过自适应优化调整采样频率,在保证数据采样精度的前提下减少了冗余数据传输,提高无线传感网的能效水平。该文提出的时间域采样频率调整算法综合考虑了感知数据的时空联合相关性特点,仿真结果验证了该文算法的性能优势。