Event region detection is the important application for wireless sensor networks（WSNs）, where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment n...Event region detection is the important application for wireless sensor networks（WSNs）, where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment nodes fault-tolerance, a novel distributed fault-tolerant detection algorithm named distributed fault-tolerance based on weighted distance（DFWD） is proposed, which exploits the spatial correlation among sensor nodes and their redundant information.In sensor networks, neighborhood sensor nodes will be endowed with different relative weights respectively according to the distances between them and the central node.Having syncretized the weighted information of dual-neighborhood nodes appropriately, it is reasonable to decide the ultimate status of the central sensor node.Simultaneously, readings of faulty sensors would be corrected during this process.Simulation results demonstrate that the DFWD has a higher fault detection accuracy compared with other algorithms, and when the sensor fault probability is 10%, the DFWD can still correct more than 91% faulty sensor nodes, which significantly improves the performance of the whole sensor network.展开更多
As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery...As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery fault diagnosis.The traditional signal processing methods,such as classical inference and weighted averaging algorithm usually lack dynamic adaptability that is easy for trends to cause the faults to be misjudged or left out.To enhance the measuring veracity and precision of vibration signal in rotary machine multi-sensor vibration signal fault diagnosis,a novel data level fusion approach is presented on the basis of correlation function analysis to fast determine the weighted value of multi-sensor vibration signals.The approach doesn＇t require knowing the prior information about sensors,and the weighted value of sensors can be confirmed depending on the correlation measure of real-time data tested in the data level fusion process.It gives greater weighted value to the greater correlation measure of sensor signals,and vice versa.The approach can effectively suppress large errors and even can still fuse data in the case of sensor failures because it takes full advantage of sensor＇s own-information to determine the weighted value.Moreover,it has good performance of anti-jamming due to the correlation measures between noise and effective signals are usually small.Through the simulation of typical signal collected from multi-sensors,the comparative analysis of dynamic adaptability and fault tolerance between the proposed approach and traditional weighted averaging approach is taken.Finally,the rotor dynamics and integrated fault simulator is taken as an example to verify the feasibility and advantages of the proposed approach,it is shown that the multi-sensor data level fusion based on correlation function weighted approach is better than the traditional weighted average approach with respect to fusion precision and dynamic adaptability.Meantime,the approach is adaptable and easy to use,can be applied to other areas of vibration measurement.展开更多
In wireless sensor networks, data missing is a common problem due to sensor faults, time synchronization, malicious attacks, and communication malfunctions, which may degrade the network＇ s performance or lead to ine...In wireless sensor networks, data missing is a common problem due to sensor faults, time synchronization, malicious attacks, and communication malfunctions, which may degrade the network＇ s performance or lead to inefficient decisions. Therefore, it is necessary to effectively estimate the missing data. A double weighted least squares support vector machines （DWLS-SVM） model for the missing data estimation in wireless sensor networks is proposed in this paper. The algo- rithm first applies the weighted LS-SVM （WLS-SVM） to estimate the missing data on temporal do- main and spatial domain respectively, and then uses the weighted average of these two candidates as the final estimated value. DWLS-SVM considers the possibility of outliers in the dataset and utilizes spatio-temporal dependencies among sensor nodes fully, which makes the estimate more robust and precise. Experimental results on real world dataset demonstrate that the proposed algorithm is outli- er robust and can estimate the missing values accurately.展开更多
It is well known that the Two-step Weighted Least-Squares(TWLS) is a widely used method for source localization and sensor position refinement. For this reason, we propose a unified framework of the TWLS method for jo...It is well known that the Two-step Weighted Least-Squares(TWLS) is a widely used method for source localization and sensor position refinement. For this reason, we propose a unified framework of the TWLS method for joint estimation of multiple disjoint sources and sensor locations in this paper. Unlike some existing works, the presented method is based on more general measurement model, and therefore it can be applied to many different localization scenarios.Besides, it does not have the initialization and local convergence problem. The closed-form expression for the covariance matrix of the proposed TWLS estimator is also derived by exploiting the first-order perturbation analysis. Moreover, the estimation accuracy of the TWLS method is shown analytically to achieve the Cramér-Rao Bound(CRB) before the threshold effect takes place. The theoretical analysis is also performed in a common mathematical framework, rather than aiming at some specific signal metrics. Finally, two numerical experiments are performed to support the theoretical development in this paper.展开更多
The underwater wireless sensor network(UWSN) has the features of mobility by drifting,less beacon nodes,longer time for localization and more energy consumption than the terrestrial sensor networks,which makes it more...The underwater wireless sensor network(UWSN) has the features of mobility by drifting,less beacon nodes,longer time for localization and more energy consumption than the terrestrial sensor networks,which makes it more difficult to locate the nodes in marine environment.Aiming at the characteristics of UWSN,a kind of cooperative range-free localization method based on weighted centroid localization(WCL) algorithm for three-dimensional UWSN is proposed.The algorithm assigns the cooperative weights for the beacon nodes according to the received acoustic signal strength,and uses the located unknown nodes as the new beacon nodes to locate the other unknown nodes,so a fast localization can be achieved for the whole sensor networks.Simulation results indicate this method has higher localization accuracy than the centroid localization algorithm,and it needs less beacon nodes and achieves higher rate of effective localization.展开更多
In this paper, an energy efficient clustering algorithm based on neighbors （EECABN） for wireless sensor networks is proposed. In the algorithm, an optimized weight of nodes is introduced to determine the priority of...In this paper, an energy efficient clustering algorithm based on neighbors （EECABN） for wireless sensor networks is proposed. In the algorithm, an optimized weight of nodes is introduced to determine the priority of clustering procedure. As improvement, the weight is a measurement of energy and degree as usual, and even associates with distance from neighbors, distance to the sink node, and other factors. To prevent the low energy nodes being exhausted with energy, the strong nodes should have more opportunities to act as cluster heads during the clustering procedure. The simulation results show that the algorithm can effectively prolong whole the network lifetime. Especially at the early stage that some nodes in the network begin to die, the process can be postponed by using the algorithm.展开更多
Anomaly detection plays an important role in ensuring the data quality in wireless sensor networks(WSNs).The main objective of the paper is to design a light-weight and distributed algorithm to detect the data collect...Anomaly detection plays an important role in ensuring the data quality in wireless sensor networks(WSNs).The main objective of the paper is to design a light-weight and distributed algorithm to detect the data collected from WSNs effectively.This is achieved by proposing a distributed anomaly detection algorithm based on ensemble isolation principle.The new method offers distinctive advantages over the existing methods.Firstly,it does not require any distance or density measurement,which reduces computational burdens significantly.Secondly,considering the spatial correlation characteristic of node deployment in WSNs,local sub-detector is built in each sensor node,which is broadcasted simultaneously to neighbor sensor nodes.A global detector model is then constructed by using the local detector model and the neighbor detector model,which possesses a distributed nature and decreases communication burden.The experiment results on the labeled dataset confirm the effectiveness of the proposed method.展开更多
Weigh-in-Motion（WIM） technique is the process of measuring the dynamic tire forces of a moving vehicle and estimating the corresponding tire loads of the static vehicle. Compared with the static weigh station, WIM s...Weigh-in-Motion（WIM） technique is the process of measuring the dynamic tire forces of a moving vehicle and estimating the corresponding tire loads of the static vehicle. Compared with the static weigh station, WIM station is an efficient and cost effective choice that will minimize unneccessary stops and delay for truckers. The way to turn birefringence of single-mode fiber into a prime quality for a powerful and reliable sensor is shown. Preliminary results for the development of a weigh-in-motion （WIM） technique based on sagnac-loop sensor are presented. After a brief description of the sensor and its principle of operation, the theoretical model characterization made in is developed. Then, a full static conditions is presented.展开更多
In wireless sensor networks, target classification differs from that in centralized sensing systems because of the distributed detection, wireless communication and limited resources. We study the classification probl...In wireless sensor networks, target classification differs from that in centralized sensing systems because of the distributed detection, wireless communication and limited resources. We study the classification problem of moving vehicles in wireless sensor networks using acoustic signals emitted from vehicles. Three algorithms including wavelet decomposition, weighted k-nearest-neighbor and Dempster-Shafer theory are combined in this paper. Finally, we use real world experimental data to validate the classification methods. The result shows that wavelet based feature extraction method can extract stable features from acoustic signals. By fusion with Dempster's rule, the classification performance is improved.展开更多
同时定位与建图(simultaneous localization and mapping,SLAM)是地下空间自主探测、自动巡检和应急救援的关键。然而,地下空间巷道狭长、地形复杂、光照不均等使得激光点云和视觉图像匹配极易发生退化,进而导致多源传感器数据融合SLAM...同时定位与建图(simultaneous localization and mapping,SLAM)是地下空间自主探测、自动巡检和应急救援的关键。然而,地下空间巷道狭长、地形复杂、光照不均等使得激光点云和视觉图像匹配极易发生退化,进而导致多源传感器数据融合SLAM精度不足,甚至失效。为此,本文提出一种增强稳健性的多源传感器数据动态加权融合SLAM方法。首先,在视觉图像预处理阶段,采用了一种基于色调、饱和度、亮度(hue,stauration,value,HSV)空间的图像增强技术,结合单参数同态滤波和对比度受限的自适应直方图均衡化(contrast limited adaptive histogram equalization,CLAHE)算法,有效提升了地下空间图像的亮度和对比度,从而增强了视觉里程计的稳健性。然后,通过马氏距离一致性检验方法对各传感器的数据质量进行评估,分析数据退化情况,并自适应地选择适合当前场景的传感器数据进行融合。最后,在综合考虑各传感器关键参数的基础上,构建了多源传感器因子图模型,并根据数据质量动态调整各传感器数据融合因子的权重,形成多源传感器数据权重动态组合模型。为验证本文方法的有效性,使用自主设计集成的移动机器人在地下走廊、开挖的地铁隧道和煤矿巷道等典型地下空间中分别进行了试验,并与多种主流SLAM方法进行定性、定量对比分析。结果表明:本文方法最大轨迹均方根误差(root mean square error,RMSE)仅为0.19 m,以高精度地面三维激光扫描获取的点云为参考,平均点云直接距离比较(cloud to cloud,C2C)小于0.13 m,所构建的点云地图具有较好的全局一致性和几何结构真实性,验证了本文方法在复杂地下空间具有更高的精度和稳健性。展开更多
基金supported by the National Science Foundation for Outstanding Young Scientists (60425310)the Science Foundation for Post-doctoral Scientists of Central South University (2008)
文摘Event region detection is the important application for wireless sensor networks（WSNs）, where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment nodes fault-tolerance, a novel distributed fault-tolerant detection algorithm named distributed fault-tolerance based on weighted distance（DFWD） is proposed, which exploits the spatial correlation among sensor nodes and their redundant information.In sensor networks, neighborhood sensor nodes will be endowed with different relative weights respectively according to the distances between them and the central node.Having syncretized the weighted information of dual-neighborhood nodes appropriately, it is reasonable to decide the ultimate status of the central sensor node.Simultaneously, readings of faulty sensors would be corrected during this process.Simulation results demonstrate that the DFWD has a higher fault detection accuracy compared with other algorithms, and when the sensor fault probability is 10%, the DFWD can still correct more than 91% faulty sensor nodes, which significantly improves the performance of the whole sensor network.
基金supported by National Hi-tech Research and Development Program of China (863 Program, Grant No. 2007AA04Z433)Hunan Provincial Natural Science Foundation of China (Grant No. 09JJ8005)Scientific Research Foundation of Graduate School of Beijing University of Chemical and Technology,China (Grant No. 10Me002)
文摘As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery fault diagnosis.The traditional signal processing methods,such as classical inference and weighted averaging algorithm usually lack dynamic adaptability that is easy for trends to cause the faults to be misjudged or left out.To enhance the measuring veracity and precision of vibration signal in rotary machine multi-sensor vibration signal fault diagnosis,a novel data level fusion approach is presented on the basis of correlation function analysis to fast determine the weighted value of multi-sensor vibration signals.The approach doesn＇t require knowing the prior information about sensors,and the weighted value of sensors can be confirmed depending on the correlation measure of real-time data tested in the data level fusion process.It gives greater weighted value to the greater correlation measure of sensor signals,and vice versa.The approach can effectively suppress large errors and even can still fuse data in the case of sensor failures because it takes full advantage of sensor＇s own-information to determine the weighted value.Moreover,it has good performance of anti-jamming due to the correlation measures between noise and effective signals are usually small.Through the simulation of typical signal collected from multi-sensors,the comparative analysis of dynamic adaptability and fault tolerance between the proposed approach and traditional weighted averaging approach is taken.Finally,the rotor dynamics and integrated fault simulator is taken as an example to verify the feasibility and advantages of the proposed approach,it is shown that the multi-sensor data level fusion based on correlation function weighted approach is better than the traditional weighted average approach with respect to fusion precision and dynamic adaptability.Meantime,the approach is adaptable and easy to use,can be applied to other areas of vibration measurement.
基金Supported by Basic Research Foundation of Beijing Institute of Technology (20070542009)
文摘In wireless sensor networks, data missing is a common problem due to sensor faults, time synchronization, malicious attacks, and communication malfunctions, which may degrade the network＇ s performance or lead to inefficient decisions. Therefore, it is necessary to effectively estimate the missing data. A double weighted least squares support vector machines （DWLS-SVM） model for the missing data estimation in wireless sensor networks is proposed in this paper. The algo- rithm first applies the weighted LS-SVM （WLS-SVM） to estimate the missing data on temporal do- main and spatial domain respectively, and then uses the weighted average of these two candidates as the final estimated value. DWLS-SVM considers the possibility of outliers in the dataset and utilizes spatio-temporal dependencies among sensor nodes fully, which makes the estimate more robust and precise. Experimental results on real world dataset demonstrate that the proposed algorithm is outli- er robust and can estimate the missing values accurately.
基金co-supported by the National Natural Science Foundation of China (Nos. 61201381, 61401513 and 61772548)the China Postdoctoral Science Foundation (No. 2016M592989)+1 种基金the Self-Topic Foundation of Information Engineering University, China (No. 2016600701)the Outstanding Youth Foundation of Information Engineering University, China (No. 2016603201)
文摘It is well known that the Two-step Weighted Least-Squares(TWLS) is a widely used method for source localization and sensor position refinement. For this reason, we propose a unified framework of the TWLS method for joint estimation of multiple disjoint sources and sensor locations in this paper. Unlike some existing works, the presented method is based on more general measurement model, and therefore it can be applied to many different localization scenarios.Besides, it does not have the initialization and local convergence problem. The closed-form expression for the covariance matrix of the proposed TWLS estimator is also derived by exploiting the first-order perturbation analysis. Moreover, the estimation accuracy of the TWLS method is shown analytically to achieve the Cramér-Rao Bound(CRB) before the threshold effect takes place. The theoretical analysis is also performed in a common mathematical framework, rather than aiming at some specific signal metrics. Finally, two numerical experiments are performed to support the theoretical development in this paper.
基金National Nature Science Foundation of China(No.61273068)International Exchanges and Cooperation Projects of Shanghai Science and Technology Committee,China(No.15220721800)
文摘The underwater wireless sensor network(UWSN) has the features of mobility by drifting,less beacon nodes,longer time for localization and more energy consumption than the terrestrial sensor networks,which makes it more difficult to locate the nodes in marine environment.Aiming at the characteristics of UWSN,a kind of cooperative range-free localization method based on weighted centroid localization(WCL) algorithm for three-dimensional UWSN is proposed.The algorithm assigns the cooperative weights for the beacon nodes according to the received acoustic signal strength,and uses the located unknown nodes as the new beacon nodes to locate the other unknown nodes,so a fast localization can be achieved for the whole sensor networks.Simulation results indicate this method has higher localization accuracy than the centroid localization algorithm,and it needs less beacon nodes and achieves higher rate of effective localization.
基金Project supported by the Shanghai Leading Academic Discipline Project (Grant No.S30108)
文摘In this paper, an energy efficient clustering algorithm based on neighbors （EECABN） for wireless sensor networks is proposed. In the algorithm, an optimized weight of nodes is introduced to determine the priority of clustering procedure. As improvement, the weight is a measurement of energy and degree as usual, and even associates with distance from neighbors, distance to the sink node, and other factors. To prevent the low energy nodes being exhausted with energy, the strong nodes should have more opportunities to act as cluster heads during the clustering procedure. The simulation results show that the algorithm can effectively prolong whole the network lifetime. Especially at the early stage that some nodes in the network begin to die, the process can be postponed by using the algorithm.
基金supported by the National High Technology Research and Development Program of China(No.2011AA040103-7)the National Key Scientific Instrument and Equipment Development Project(No.2012YQ15008703)+3 种基金the Zhejiang Provincial Natural Science Foundation of China(No.LY13F020015)National Science Foundation of China(No.61104089)Science and Technology Commission of Shanghai Municipality(No.11JC1404000)Shanghai Rising-Star Program(No.13QA1401600)
文摘Anomaly detection plays an important role in ensuring the data quality in wireless sensor networks(WSNs).The main objective of the paper is to design a light-weight and distributed algorithm to detect the data collected from WSNs effectively.This is achieved by proposing a distributed anomaly detection algorithm based on ensemble isolation principle.The new method offers distinctive advantages over the existing methods.Firstly,it does not require any distance or density measurement,which reduces computational burdens significantly.Secondly,considering the spatial correlation characteristic of node deployment in WSNs,local sub-detector is built in each sensor node,which is broadcasted simultaneously to neighbor sensor nodes.A global detector model is then constructed by using the local detector model and the neighbor detector model,which possesses a distributed nature and decreases communication burden.The experiment results on the labeled dataset confirm the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China under Grant No. 60707021Science and Technology Commission of Shanghai Municipality under Grant No. 03dz11003.
文摘Weigh-in-Motion（WIM） technique is the process of measuring the dynamic tire forces of a moving vehicle and estimating the corresponding tire loads of the static vehicle. Compared with the static weigh station, WIM station is an efficient and cost effective choice that will minimize unneccessary stops and delay for truckers. The way to turn birefringence of single-mode fiber into a prime quality for a powerful and reliable sensor is shown. Preliminary results for the development of a weigh-in-motion （WIM） technique based on sagnac-loop sensor are presented. After a brief description of the sensor and its principle of operation, the theoretical model characterization made in is developed. Then, a full static conditions is presented.
基金Supported by National Natural Science Foundation of China （60874063）, and Innovation and Scientific Research Foundation of Graduate Student of Heilongjiang Province （YJSCX2012-263HLJ）
基金Supported in part by Science & Technology Department of Shanghai (05dz15004)
文摘In wireless sensor networks, target classification differs from that in centralized sensing systems because of the distributed detection, wireless communication and limited resources. We study the classification problem of moving vehicles in wireless sensor networks using acoustic signals emitted from vehicles. Three algorithms including wavelet decomposition, weighted k-nearest-neighbor and Dempster-Shafer theory are combined in this paper. Finally, we use real world experimental data to validate the classification methods. The result shows that wavelet based feature extraction method can extract stable features from acoustic signals. By fusion with Dempster's rule, the classification performance is improved.
文摘同时定位与建图(simultaneous localization and mapping,SLAM)是地下空间自主探测、自动巡检和应急救援的关键。然而,地下空间巷道狭长、地形复杂、光照不均等使得激光点云和视觉图像匹配极易发生退化,进而导致多源传感器数据融合SLAM精度不足,甚至失效。为此,本文提出一种增强稳健性的多源传感器数据动态加权融合SLAM方法。首先,在视觉图像预处理阶段,采用了一种基于色调、饱和度、亮度(hue,stauration,value,HSV)空间的图像增强技术,结合单参数同态滤波和对比度受限的自适应直方图均衡化(contrast limited adaptive histogram equalization,CLAHE)算法,有效提升了地下空间图像的亮度和对比度,从而增强了视觉里程计的稳健性。然后,通过马氏距离一致性检验方法对各传感器的数据质量进行评估,分析数据退化情况,并自适应地选择适合当前场景的传感器数据进行融合。最后,在综合考虑各传感器关键参数的基础上,构建了多源传感器因子图模型,并根据数据质量动态调整各传感器数据融合因子的权重,形成多源传感器数据权重动态组合模型。为验证本文方法的有效性,使用自主设计集成的移动机器人在地下走廊、开挖的地铁隧道和煤矿巷道等典型地下空间中分别进行了试验,并与多种主流SLAM方法进行定性、定量对比分析。结果表明:本文方法最大轨迹均方根误差(root mean square error,RMSE)仅为0.19 m,以高精度地面三维激光扫描获取的点云为参考,平均点云直接距离比较(cloud to cloud,C2C)小于0.13 m,所构建的点云地图具有较好的全局一致性和几何结构真实性,验证了本文方法在复杂地下空间具有更高的精度和稳健性。
