Efficient distributed data scheduling algorithm for data aggregation in wireless sensor networks

With the rapid development of applications for wireless sensor networks, efficient data aggregation methods are becoming increasingly emphasized. Many researchers have studied the problem of reporting data with minimum energy cost when data is allowed to be aggregated many times. However, some aggregation functions used to aggregate multiple data into one packet are unrepeatable; that is, every data is aggregated only at most once. This problem motivated us to study reporting data with minimum energy cost subject to that a fixed number of data are allowed to be aggregated into one packet and every data is aggregated at most once. In this paper, we propose novel data aggregation and routing structures for reporting generated data. With the structures, we study the problem of scheduling data to nodes in the networks for data aggregation such that the energy cost of reporting data is minimized, termed MINIMUM ENERGY-COST DATA-AGGREGATION SCHEDULING. In addition, we show that MINIMUM ENERGY-COST DATA-AGGREGATION SCHEDULING is NP-complete. Furthermore, a distributed data scheduling algorithm is proposed accordingly. Simulations show that the proposed algorithm provides a good solution for MINIMUM ENERGY-COST DATA-AGGREGATION SCHEDULING.     

Energy-efficient cooperative data aggregation for wireless sensor networks

Recently, cooperative communication mechanism is shown to be a promising technology to improve the transmit diversity only by a single transceiver antenna. Using this communication paradigm, multiple source nodes are able to coordinate their transmissions so as to obtain energy savings. As data aggregation is one of the most important operations in wireless sensor networks, this paper studies the energy-efficient data aggregation problem through cooperative communication. We first define the cooperative data aggregation (CDA) problem, and formally prove that this problem is NP-Hard. Due to the difficult nature of this problem, we propose a heuristic algorithm MCT for cooperative data aggregation. The theoretical analysis shows that this algorithm can reach the approximate performance ratio of 2. Moreover, the distributed implementation DMCT of the algorithm is also described. We prove that both centralized and distributed algorithms can construct the same topology for cooperative data aggregation. The experimental simulations show that the proposed algorithms will decrease the power consumption by about 12.5% and 66.3% compared with PEDAP and PEGASIS algorithms respectively.     

An energy-efficient protocol for data gathering and aggregation in wireless sensor networks

Data gathering is a major function of many applications in wireless sensor networks (WSNs). The most important issue in designing a data gathering algorithm is how to save energy of sensor nodes while meeting the requirement of applications/users such as sensing area coverage. In this paper, we propose a novel hierarchical clustering protocol (DEEG) for long-lived sensor network. DEEG achieves a good performance in terms of lifetime by minimizing energy consumption for in-network communications and balancing the energy load among all the nodes, the proposed protocol achieves a good performance in terms of network lifetime. DEEG can also handle the energy hetergenous capacities and guarantee that out-network communications always occur in the subregion with high energy reserved. Furthermore, it introduces a simple but efficient approach to cope with the area coverage problem. We evaluate the performance of the proposed protocol using a simple temperature sensing application. Simulation results show that our protocol significantly outperforms LEACH and PEGASIS in terms of network lifetime and the amount of data gathered.

A simple, least-time, and energy-efficient routing protocol with one-level data aggregation for wireless sensor networks

The area of wireless sensor networks (WSN) is currently attractive in the research community area due to its applications in diverse fields such as defense security, civilian applications and medical research. Routing is a serious issue in WSN due to the use of computationally-constrained and resource-constrained micro-sensors. These constraints prohibit the deployment of traditional routing protocols designed for other ad hoc wireless networks. Any routing protocol designed for use in WSN should be reliable, energy-efficient and should increase the lifetime of the network. We propose a simple, least-time, energy-efficient routing protocol with one-level data aggregation that ensures increased life time for the network. The proposed protocol was compared with popular ad hoc and sensor network routing protocols, viz., AODV ( [35] and [12]), DSR (Johnson et al., 2001), DSDV (Perkins and Bhagwat, 1994), DD (Intanagonwiwat et al., 2000) and MCF (Ye et al., 2001). It was observed that the proposed protocol outperformed them in throughput, latency, average energy consumption and average network lifetime. The proposed protocol uses absolute time and node energy as the criteria for routing, this ensures reliability and congestion avoidance.     

无线传感网络中的分簇融合决策方法

无线传感网络的簇划分和簇内节点访问顺序对数据融合决策能耗和耗时具有重要影响．对此,提出一种分簇融合方法,采用最大熵聚类法和蚁群算法实现分簇和节点访问顺序规划,在簇内由移动代理以渐近方式完成局部融合,中心服务节点通过二次融合得到最终结果．仿真实验以能耗×耗时为评价指标,分析了簇数目对数据融合效率和准确性的影响．验证了分簇融合决策方法能有效降低网络能耗和耗时．提高融合准确性和执行效率．     

Secure and energy-efficient data aggregation with malicious aggregator identification in wireless sensor networks

Data aggregation in wireless sensor networks is employed to reduce the communication overhead and prolong the network lifetime. However, an adversary may compromise some sensor nodes, and use them to forge false values as the aggregation result. Previous secure data aggregation schemes have tackled this problem from different angles. The goal of those algorithms is to ensure that the Base Station (BS) does not accept any forged aggregation results. But none of them have tried to detect the nodes that inject into the network bogus aggregation results. Moreover, most of them usually have a communication overhead that is (at best) logarithmic per node. In this paper, we propose a secure and energy-efficient data aggregation scheme that can detect the malicious nodes with a constant per node communication overhead. In our solution, all aggregation results are signed with the private keys of the aggregators so that they cannot be altered by others. Nodes on each link additionally use their pairwise shared key for secure communications. Each node receives the aggregation results from its parent (sent by the parent of its parent) and its siblings (via its parent node), and verifies the aggregation result of the parent node. Theoretical analysis on energy consumption and communication overhead accords with our comparison based simulation study over random data aggregation trees.     

蚁群算法在无线传感器网络路由中的应用研究

设计合理的路由算法是无线传感器网络中的核心问题之一。基于蚁群算法提出了一种可用于无线传感器网络的单播路由算法,该算法利用蚁群算法正反馈及分布式计算的特点寻找从源节点目的节点的最少跳数路径。仿真实验证明了该算法是合理的及有效的,具有可扩展性的特点,同时在收敛速度和鲁棒性上优于典型的单播路由算法。     

一种基于蚁群优化的WSN拥塞控制算法*

针对无线传感器网络中由于拥塞引起的丢包和能量过度消耗等问题,提出了一种基于蚁群优化的拥塞控制算法以减轻WSN中的拥塞和改进网络性能。该算法充分考虑了给定时刻WSN的拥塞状况,分成三个阶段在源节点和sink节点间寻找一条最佳的路径,并及时地消除拥塞。仿真实验结果表明,该算法在网络吞吐量、丢包率、时延和能耗方面具有较好的综合网络性能。     

基于MMAS的无线传感器网络数据融合算法*

提出了一种基于MAXMIN蚂蚁系统（MMAS）无线传感器网络的数据融合算法。该算法采用定向扩散的机制进行兴趣散布;利用MMAS算法构造一个最小Steiner树,源节点的数据发送到构造好的最小Steiner树上,经过融合后传输到sink节点,降低了网络中传输的数据量。通过与Dijkstra算法比较,NS2仿真表明该算法降低了网络能耗,增加了网络生存时间。     

Energy-efficient and high-accuracy secure data aggregation in wireless sensor networks

Due to the inherent characteristics of resource-constrained sensors, communication overhead is always a major concern in wireless sensor networks (WSNs). Data aggregation is an essential technique to reduce the communication overhead and prolong network lifetime. Since data aggregation results are usually used to make critical decisions, the accuracy of final aggregation results is very important. Furthermore, as wireless sensor networks are increasing being deployed in security-critical applications, we should take security into consideration as well. Therefore, for such applications, data aggregation protocols must be highly energy efficient and highly accurate while being able to prevent an adversary from stealing private data held by each sensor node. In this paper, we propose an energy-efficient and high-accuracy (EEHA) scheme for secure data aggregation. The main idea of our scheme is that accurate data aggregation is achieved without releasing private sensor readings and without introducing significant overhead on the battery-limited sensors. We conduct extensive simulations to evaluate the performance of EEHA. Our analysis and simulations show that EEHA is more efficient and accurate than the existing scheme.     

WSN中改进蚁群算法求解移动代理问题*

关于求解无线传感器网络中移动代理迁移路径问题,在蚁群系统基础上对蚁群算法进行改进,使算法更适用于无线传感器网络环境。从大量初始化路径中选出部分最优路径留下信息素,而且考虑节点的剩余能量,从而引导蚂蚁选择不同的路径;同时,针对无线传感器网络节点通信能力有限的特点,为了避免无效路径的产生引入变异操作。理论分析和仿真实验表明,改进后的蚁群算法增强了算法的全局搜索能力并有效求解无线传感器网络移动代理迁移路径问题。     

Prediction-based data aggregation in wireless sensor networks: Combining grey model and Kalman Filter

In many environmental monitoring applications, since the data periodically sensed by wireless sensor networks usually are of high temporal redundancy, prediction-based data aggregation is an important approach for reducing redundant data communications and saving sensor nodes’ energy. In this paper, a novel prediction-based data collection protocol is proposed, in which a double-queue mechanism is designed to synchronize the prediction data series of the sensor node and the sink node, and therefore, the cumulative error of continuous predictions is reduced. Based on this protocol, three prediction-based data aggregation approaches are proposed: Grey-Model-based Data Aggregation (GMDA), Kalman-Filter-based Data Aggregation (KFDA) and Combined Grey model and Kalman Filter Data Aggregation (CoGKDA). By integrating the merit of grey model in quick modeling with the advantage of Kalman Filter in processing data series noise, CoGKDA presents high prediction accuracy, low communication overhead, and relative low computational complexity. Experiments are carried out based on a real data set of a temperature and humidity monitoring application in a granary. The results show that the proposed approaches significantly reduce communication redundancy and evidently improve the lifetime of wireless sensor networks.     

WSNs中数据融合树的时隙分配算法

周期工作DC(Duty-Cycling)技术,即周期地开/关通信和感测能力,能够有效降低传感节点的活动时间,进而延长无线传感网络寿命.然而,此技术给数据融合提出了挑战.为此,提出免碰撞的数据融合树的时隙分配算法CF-DGSS(Collision-Free Data Aggregation Slots Scheduling Algorithm for Duty-Cycled Wireless Sensor Networks),进而解决基于DC的WSNs的数据融合时隙分配问题.为了解决碰撞问题,CF-DGSS算法给每个节点构建冲突集.每个节点在融合时隙分配过程中,保存自己的冲突集.在分配时隙时,传感节点应当确保与冲突集内节点的数据融合不干扰.仿真结果表明,与其他的分配算法相比,提出的CF-DGSS算法具有低的融合时延.     

Continuous data aggregation and capacity in probabilistic wireless sensor networks

Due to the existence of many probabilistic lossy links in Wireless Sensor Networks (WSNs) (Liu et al., 2010)  [25], it is not practical to study the network capacity issue under the Deterministic Network Model (DNM). A more realistic one is actually the Probabilistic Network Model (PNM). Therefore, we study the Snapshot Data Aggregation (SDA) problem, the Continuous Data Aggregation (CDA) problem, and their achievable capacities for probabilistic WSNs under both the independent and identically distributed (i.i.d.) node distribution model and the Poisson point distribution model in this paper. First, we partition a network into cells and use two vectors to further partition these cells into equivalent color classes. Subsequently, based on the partitioned cells and equivalent color classes, we propose a Cell-based Aggregation Scheduling (CAS) algorithm for the SDA problem in probabilistic WSNs. Theoretical analysis of CAS and the upper bound capacity of the SDA problem show that the achievable capacities of CAS are all order optimal in the worst case, the average case, and the best case. For the CDA problem in probabilistic WSNs, we propose a Level-based Aggregation Scheduling (LAS) algorithm. LAS gathers the aggregation values of continuous snapshots by forming a data aggregation/transmission pipeline on the segments and scheduling all the cell-levels in a cell-level class concurrently. By theoretical analysis of LAS and the upper bound capacity of the CDA problem, we prove that LAS also successfully achieves order optimal capacities in all the cases. The extensive simulation results further validate the effectiveness of CAS and LAS.     

Efficient fault-tolerant collision-free data aggregation scheduling for wireless sensor networks

This paper investigates the design of fault-tolerant TDMA-based data aggregation scheduling (DAS) protocols for wireless sensor networks (WSNs). DAS is a fundamental pattern of communication in wireless sensor networks where sensor nodes aggregate and relay data to a sink node. However, any such DAS protocol needs to be cognisant of the fact that crash failures can occur. We make the following contributions: (i) we identify a necessary condition to solve the DAS problem, (ii) we introduce a strong and weak version of the DAS problem, (iii) we show several impossibility results due to the crash failures, (iv) we develop a modular local algorithm that solves stabilising weak DAS and (v) we show, through simulations and an actual deployment on a small testbed, how specific instantiations of parameters can lead to the algorithm achieving very efficient stabilisation.     

An adaptive in-network aggregation operator for query processing in wireless sensor networks

A wireless sensor network (WSN) is composed of tens or hundreds of spatially distributed autonomous nodes, called sensors. Sensors are devices used to collect data from the environment related to the detection or measurement of physical phenomena. In fact, a WSN consists of groups of sensors where each group is responsible for providing information about one or more physical phenomena (e.g., group for collecting temperature data). Sensors are limited in power, computational capacity, and memory. Therefore, a query engine and query operators for processing queries in WSNs should be able to handle resource limitations such as memory and battery life. Adaptability has been explored as an alternative approach when dealing with these conditions. Adaptive query operators (algorithms) can adjust their behavior in response to specific events that take place during data processing. In this paper, we propose an adaptive in-network aggregation operator for query processing in sensor nodes of a WSN, called ADAGA (ADaptive AGgregation Algorithm for sensor networks). The ADAGA adapts its behavior according to memory and energy usage by dynamically adjusting data-collection and data-sending time intervals. ADAGA can correctly aggregate data in WSNs with packet replication. Moreover, ADAGA is able to predict non-performed detection values by analyzing collected values. Thus, ADAGA is able to produce results as close as possible to real results (obtained when no resource constraint is faced). The results obtained through experiments prove the efficiency of ADAGA.     

FAMACROW: Fuzzy and ant colony optimization based combined mac,routing, and unequal clustering cross-layer protocol for wireless sensor networks

This paper presents Fuzzy and Ant Colony Optimization Based Combined MAC, Routing, and Unequal Clustering Cross-Layer Protocol for Wireless Sensor Networks (FAMACROW) consisting of several nodes that send sensed data to a Master Station. FAMACROW incorporates cluster head selection, clustering, and inter-cluster routing protocols. FAMACROW uses fuzzy logic with residual energy, number of neighboring nodes, and quality of communication link as input variables for cluster head selection. To avoid hot spots problem, FAMACROW uses an unequal clustering mechanism with clusters closer to MS having smaller sizes than those far from it. FAMACROW uses Ant Colony Optimization based technique for reliable and energy-efficient inter-cluster multi-hop routing from cluster heads to MS. The inter-cluster routing protocol decides relay node considering its: (i) distance from current cluster head and that from MS (for energy-efficient inter-cluster communication), (ii) residual energy (for energy distribution across the network), (iii) queue length (for congestion control), (iv) delivery likelihood (for reliable communication). A comparative analysis of FAMACROW with Unequal Cluster Based Routing [33], Unequal Layered Clustering Approach [43], Energy Aware Unequal Clustering using Fuzzy logic [37] and Improved Fuzzy Unequal Clustering [35] shows that FAMACROW is 41% more energy-efficient, has 75–88% more network lifetime and sends 82% more packets compared to Improved Fuzzy Unequal Clustering protocol.     

无线传感器网络中数据融合算法研究

在提供高效的数据融合的同时保障数据的安全是无线传感器网络的研究的一个具有挑战性的问题。本文为加法融合函数设计了一种具有隐私保护功能的数据融合算法——基于分簇的安全数据融合。该算法利用了分簇协议和多项式的代数性质。其优点为带来的通信开销较小。研究的主要目标是提高无线传感器网络中数据融合效率的同时,保证数据的安全性。     

传感器网络中基于域的聚集算法

聚集运算是传感器网络查询处理中最重要的一个运算。提出了一种基于域聚簇的网内聚集算法PIA。在PIA中,首先结合传感器网络的节点特性和位置信息,提出了一种基于域的分布式数据汇聚模型,把传感器网络按域划分来构建连通核,查询只需在连通核中寻径,因而能明显降低寻径时间复杂度并且具有更好的分布性。在PIA中,核心节点把当前路径中的Max和Min值传送到节点上,如果节点的值不符合要求就放弃本次传送,因而能够明显减少数据的传送次数,从而达到节省能量的目的。理论分析和实验表明该算法较传统算法在节省能量上有较好的表现。     

TACO-miner: An ant colony based algorithm for rule extraction from trained neural networks

Extracting classification rules from data is an important task of data mining and gaining considerable more attention in recent years. In this paper, a new meta-heuristic algorithm which is called as TACO-miner is proposed for rule extraction from artificial neural networks (ANN). The proposed rule extraction algorithm actually works on the trained ANNs in order to discover the hidden knowledge which is available in the form of connection weights within ANN structure. The proposed algorithm is mainly based on a meta-heuristic which is known as touring ant colony optimization (TACO) and consists of two-step hierarchical structure. The proposed algorithm is experimentally evaluated on six binary and n-ary classification benchmark data sets. Results of the comparative study show that TACO-miner is able to discover accurate and concise classification rules.