无线传感器网络(Wireless Sensor Network,WSN)作为物联网的核心组成部分,在环境监测、智能家居和目标追踪等领域具有广泛的应用前景。然而,基于接收信号强度指示(Received Signal Strength Indication,RSSI)的定位算法在复杂环境中常...无线传感器网络(Wireless Sensor Network,WSN)作为物联网的核心组成部分,在环境监测、智能家居和目标追踪等领域具有广泛的应用前景。然而,基于接收信号强度指示(Received Signal Strength Indication,RSSI)的定位算法在复杂环境中常因多径效应、非视距(Non Line of Sight,NLOS)传播及信号衰减等问题,导致定位精度和鲁棒性不足。针对这一挑战,提出了一种面向高精度与高鲁棒性的WSN中RSSI定位算法优化方法。该方法的主要创新点为:基于隔离森林的超宽带(Ultra-Wideband,UWB)异常检测。通过无监督学习识别并剔除NLOS环境下的异常测距数据,显著降低多径干扰对定位的影响;多层感知器(Multilayer Perceptron,MLP)自适应噪声调整。利用MLP动态建模RSSI-距离关系,实时调整扩展卡尔曼滤波(Extended Kalman Filter,EKF)的过程噪声协方差矩阵,提升算法对动态环境的适应性,融合机器学习的改进EKF框架。结合多新息EKF(Multi-Innovation EKF,MIEKF)与加权最小二乘法(Weighted Least Squares,WLS),通过滑动窗口机制融合历史观测数据,减少线性化误差累积,定位均方根误差(Root Mean Square Error,RMSE)降至0.18 m。实验结果表明,在弱信号和NLOS占比30%的复杂场景下,该方法较传统RSSI定位方法精度提升25%以上,且通过异常检测与动态噪声抑制机制,定位成功率稳定在90%以上,显著增强了系统的鲁棒性。所提方法为WSN在复杂环境中的高精度定位提供了可靠的技术支持。展开更多
In this paper, we present a malicious node detection scheme using confidence-level evaluation in a grid-based wireless sensor network. The sensor field is divided into square grids, where sensor nodes in each grid for...In this paper, we present a malicious node detection scheme using confidence-level evaluation in a grid-based wireless sensor network. The sensor field is divided into square grids, where sensor nodes in each grid form a cluster with a cluster head. Each cluster head maintains the confidence levels of its member nodes based on their readings and reflects them in decision-making. Two thresholds are used to distinguish between false alarms due to malicious nodes and events. In addition, the center of an event region is estimated, if necessary, to enhance the event and malicious node detection accuracy. Experimental results show that the scheme can achieve high malicious node detection accuracy without sacrificing normal sensor nodes.展开更多
Sensor nodes in a wireless sensor network （WSN） are typically powered by batteries, thus the energy is constrained. It is our design goal to efficiently utilize the energy of each sensor node to extend its lifetime,...Sensor nodes in a wireless sensor network （WSN） are typically powered by batteries, thus the energy is constrained. It is our design goal to efficiently utilize the energy of each sensor node to extend its lifetime, so as to prolong the lifetime of the whole WSN. In this paper, we propose a path-based data aggregation scheme （PBDAS） for grid-based wireless sensor networks. In order to extend the lifetime of a WSN, we construct a grid infrastructure by partitioning the whole sensor field into a grid of cells. Each cell has a head responsible for aggregating its own data with the data sensed by the others in the same cell and then transmitting out. In order to efficiently and rapidly transmit the data to the base station （BS）, we link each cell head to form a chain. Each cell head on the chain takes turn becoming the chain leader responsible for transmitting data to the BS. Aggregated data moves from head to head along the chain, and finally the chain leader transmits to the BS. In PBDAS, only the cell heads need to transmit data toward the BS. Therefore, the data transmissions to the BS substantially decrease. Besides, the cell heads and chain leader are designated in turn according to the energy level so that the energy depletion of nodes is evenly distributed. Simulation results show that the proposed PBDAS extends the lifetime of sensor nodes, so as to make the lifetime of the whole network longer.展开更多
This report introduced new concept and technics for a grid-based fishery management system. The fishing ground was first divided into small grid of equal area, each with predefined longitudes and latitudes (both 0.033...This report introduced new concept and technics for a grid-based fishery management system. The fishing ground was first divided into small grid of equal area, each with predefined longitudes and latitudes (both 0.033 degrees or approximately 2 × 2 nautical miles in this study). All grids were laid and formatted into a Microsoft-Excel spreadsheet system, as defined by the coastline. Individual sheets were also constructed to represent different ecological characters, serving as supporting data of the main grid-map. Including individual fishing record, water depth, wind & current vector, benthic character, etc. Cellular automata (CA) mathematics was applied for simulation studies. They were programmed on the built-in Visual BASIC langrage in EXCEL. In a three-year research project, the author was able to accomplish the following major results: 1) An EXCEL-based spreadsheet system for storage of fishing effort in each grid. Provided that data of fishing yield is also available for each grid, research model for fishery management can be constructed, leading toward solutions for total allowable catch (TAC) as well as maximum economic yield (MEY). 2) A multi-layered, 2-dimentional spread-sheet system demonstrating the distribution of relative intensity for individual grids. The system can be decked up with different ecological data for more advanced studies. 3) Estimation of the nearest distance between two special grids as well as fishing harbors. This would help in more efficient navigation management and allocation of fishing rights for the fishing vessels.展开更多
When senors transmit their data to the sink via multi-hop communication,the sensors closer to the sink are burdened with heavy relay traffic and tend to die early.On the contrary,if all sensors transmit datas to the s...When senors transmit their data to the sink via multi-hop communication,the sensors closer to the sink are burdened with heavy relay traffic and tend to die early.On the contrary,if all sensors transmit datas to the sink via single-hop communication,the sensors further from the sink will die much more quickly than those closer to the sink.In this paper,we first develop an analytical model to derive the optimal cluster radius.Then we propose a mixed communication method on grid-based where the sensors can transmit data to the sink in either single-hop or multi-hop.Finally,we conduct extensive experiments and show that our method outperforms LEACH and HEED in terms of network lifetime by balancing energy consumption.展开更多
This work proposes a geographic routing protocol for UWSNs based on the construction of a 3D virtual grid structure, called Void-Avoidance Grid-based Multipath Position-based Routing (VA-GMPR). It consists of two main...This work proposes a geographic routing protocol for UWSNs based on the construction of a 3D virtual grid structure, called Void-Avoidance Grid-based Multipath Position-based Routing (VA-GMPR). It consists of two main components, the multipath routing scheme and the grid-based void avoidance (GVA) mechanism for handling routing holes. The multipath routing scheme adopts node-disjoint routes from the source to the sink in order to enhance network reliability and load balancing. While the GVA mechanism handles the problem of holes in 3D virtual grid structure based on three techniques: Hole bypass, path diversion, and path backtracking. The performance evaluation of the VA-GMPR protocol was compared to a recently proposed grid-based routing protocol for UWSNs, called Energy-efficient Multipath Geographic Grid-based Routing (EMGGR). The results showed that the VA-GMPR protocol outperformed the EMGGR protocol in terms of packet delivery ratio, and end-to end-delay. However, the results also showed that the VA-GMPR protocol exhibited higher energy consumption compared to EMGGR.展开更多
文摘无线传感器网络(Wireless Sensor Network,WSN)作为物联网的核心组成部分,在环境监测、智能家居和目标追踪等领域具有广泛的应用前景。然而,基于接收信号强度指示(Received Signal Strength Indication,RSSI)的定位算法在复杂环境中常因多径效应、非视距(Non Line of Sight,NLOS)传播及信号衰减等问题,导致定位精度和鲁棒性不足。针对这一挑战,提出了一种面向高精度与高鲁棒性的WSN中RSSI定位算法优化方法。该方法的主要创新点为:基于隔离森林的超宽带(Ultra-Wideband,UWB)异常检测。通过无监督学习识别并剔除NLOS环境下的异常测距数据,显著降低多径干扰对定位的影响;多层感知器(Multilayer Perceptron,MLP)自适应噪声调整。利用MLP动态建模RSSI-距离关系,实时调整扩展卡尔曼滤波(Extended Kalman Filter,EKF)的过程噪声协方差矩阵,提升算法对动态环境的适应性,融合机器学习的改进EKF框架。结合多新息EKF(Multi-Innovation EKF,MIEKF)与加权最小二乘法(Weighted Least Squares,WLS),通过滑动窗口机制融合历史观测数据,减少线性化误差累积,定位均方根误差(Root Mean Square Error,RMSE)降至0.18 m。实验结果表明,在弱信号和NLOS占比30%的复杂场景下,该方法较传统RSSI定位方法精度提升25%以上,且通过异常检测与动态噪声抑制机制,定位成功率稳定在90%以上,显著增强了系统的鲁棒性。所提方法为WSN在复杂环境中的高精度定位提供了可靠的技术支持。
文摘In this paper, we present a malicious node detection scheme using confidence-level evaluation in a grid-based wireless sensor network. The sensor field is divided into square grids, where sensor nodes in each grid form a cluster with a cluster head. Each cluster head maintains the confidence levels of its member nodes based on their readings and reflects them in decision-making. Two thresholds are used to distinguish between false alarms due to malicious nodes and events. In addition, the center of an event region is estimated, if necessary, to enhance the event and malicious node detection accuracy. Experimental results show that the scheme can achieve high malicious node detection accuracy without sacrificing normal sensor nodes.
基金supported by the NSC under Grant No.NSC-101-2221-E-239-032 and NSC-102-2221-E-239-020
文摘Sensor nodes in a wireless sensor network （WSN） are typically powered by batteries, thus the energy is constrained. It is our design goal to efficiently utilize the energy of each sensor node to extend its lifetime, so as to prolong the lifetime of the whole WSN. In this paper, we propose a path-based data aggregation scheme （PBDAS） for grid-based wireless sensor networks. In order to extend the lifetime of a WSN, we construct a grid infrastructure by partitioning the whole sensor field into a grid of cells. Each cell has a head responsible for aggregating its own data with the data sensed by the others in the same cell and then transmitting out. In order to efficiently and rapidly transmit the data to the base station （BS）, we link each cell head to form a chain. Each cell head on the chain takes turn becoming the chain leader responsible for transmitting data to the BS. Aggregated data moves from head to head along the chain, and finally the chain leader transmits to the BS. In PBDAS, only the cell heads need to transmit data toward the BS. Therefore, the data transmissions to the BS substantially decrease. Besides, the cell heads and chain leader are designated in turn according to the energy level so that the energy depletion of nodes is evenly distributed. Simulation results show that the proposed PBDAS extends the lifetime of sensor nodes, so as to make the lifetime of the whole network longer.
文摘This report introduced new concept and technics for a grid-based fishery management system. The fishing ground was first divided into small grid of equal area, each with predefined longitudes and latitudes (both 0.033 degrees or approximately 2 × 2 nautical miles in this study). All grids were laid and formatted into a Microsoft-Excel spreadsheet system, as defined by the coastline. Individual sheets were also constructed to represent different ecological characters, serving as supporting data of the main grid-map. Including individual fishing record, water depth, wind & current vector, benthic character, etc. Cellular automata (CA) mathematics was applied for simulation studies. They were programmed on the built-in Visual BASIC langrage in EXCEL. In a three-year research project, the author was able to accomplish the following major results: 1) An EXCEL-based spreadsheet system for storage of fishing effort in each grid. Provided that data of fishing yield is also available for each grid, research model for fishery management can be constructed, leading toward solutions for total allowable catch (TAC) as well as maximum economic yield (MEY). 2) A multi-layered, 2-dimentional spread-sheet system demonstrating the distribution of relative intensity for individual grids. The system can be decked up with different ecological data for more advanced studies. 3) Estimation of the nearest distance between two special grids as well as fishing harbors. This would help in more efficient navigation management and allocation of fishing rights for the fishing vessels.
文摘When senors transmit their data to the sink via multi-hop communication,the sensors closer to the sink are burdened with heavy relay traffic and tend to die early.On the contrary,if all sensors transmit datas to the sink via single-hop communication,the sensors further from the sink will die much more quickly than those closer to the sink.In this paper,we first develop an analytical model to derive the optimal cluster radius.Then we propose a mixed communication method on grid-based where the sensors can transmit data to the sink in either single-hop or multi-hop.Finally,we conduct extensive experiments and show that our method outperforms LEACH and HEED in terms of network lifetime by balancing energy consumption.
文摘This work proposes a geographic routing protocol for UWSNs based on the construction of a 3D virtual grid structure, called Void-Avoidance Grid-based Multipath Position-based Routing (VA-GMPR). It consists of two main components, the multipath routing scheme and the grid-based void avoidance (GVA) mechanism for handling routing holes. The multipath routing scheme adopts node-disjoint routes from the source to the sink in order to enhance network reliability and load balancing. While the GVA mechanism handles the problem of holes in 3D virtual grid structure based on three techniques: Hole bypass, path diversion, and path backtracking. The performance evaluation of the VA-GMPR protocol was compared to a recently proposed grid-based routing protocol for UWSNs, called Energy-efficient Multipath Geographic Grid-based Routing (EMGGR). The results showed that the VA-GMPR protocol outperformed the EMGGR protocol in terms of packet delivery ratio, and end-to end-delay. However, the results also showed that the VA-GMPR protocol exhibited higher energy consumption compared to EMGGR.
