A load-balanced minimum energy routing algorithm for Wireless Ad Hoc Sensor Networks

Wireless Ad Hoc Sensor Networks (WSNs) have received considerable academia research attention at present. The energy-constraint sensor nodes in WSNs operate on limited batteries, so it is a very important issue to use energy efficiently and reduce power consumption. To maximize the network lifetime, it is essential to prolong each individual node’s lifetime through minimizing the transmission energy consumption, so that many minimum energy routing schemes for traditional mobile ad hoc network have been developed for this reason. This paper presents a novel minimum energy routing algorithm named Load-Balanced Minimum Energy Routing (LBMER) for WSNs considering both sensor nodes’ energy consumption status and the sensor nodes’ hierarchical congestion levels, which uses mixture of energy balance and traffic balance to solve the problem of “hot spots” of WSNs and avoid the situation of “hot spots” sensor nodes using their energy at much higher rate and die much faster than the other nodes. The path router established by LBMER will not be very congested and the traffic will be distributed evenly in the WSNs. Simulation results verified that the LBMER performance is better than that of Min-Hop routing and the existing minimum energy routing scheme MTPR (Total Transmission Power Routing).

Energy-balanced clustering protocol for data gathering in wireless sensor networks with unbalanced traffic load

Energy-efficient data gathering in multi-hop wireless sensor networks was studied,considering that different node produces different amounts of data in realistic environments.A novel dominating set based clustering protocol (DSCP) was proposed to solve the data gathering problem in this scenario.In DSCP,a node evaluates the potential lifetime of the network (from its local point of view) assuming that it acts as the cluster head,and claims to be a tentative cluster head if it maximizes the potential lifetime.When evaluating the potential lifetime of the network,a node considers not only its remaining energy,but also other factors including its traffic load,the number of its neighbors,and the traffic loads of its neighbors.A tentative cluster head becomes a final cluster head with a probability inversely proportional to the number of tentative cluster heads that cover its neighbors.The protocol can terminate in O(n/lg n) steps,and its total message complexity is O(n2/lg n).Simulation results show that DSCP can effectively prolong the lifetime of the network in multi-hop networks with unbalanced traffic load.Compared with EECT,the network lifetime is prolonged by 56.6% in average.

Experimental Measurements of the Sensitivity of Fiber-optic Bragg Grating Sensors with a Soft Polymeric Coating under Mechanical Loading,Thermal and Magnetic under Cryogenic Conditions

The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable （cable- around-conduit conductors, cable-in-conduit conductors）, independently or utilized together with other strain measurement methods.

Opportunistic Routing for Time-Variety and Load-Balance over Wireless Sensor Networks

To aware the topology of wireless sensor networks (WSN) with time-variety, and load-balance the resource of communication and energy, an opportunistic routing protocol for WSN based on Opportunistic Routing Entropy and ant colony optimization, called ACO-TDOP, is proposed. At first, based on the second law of thermo-dynamics, we introduce the concept of Opportunistic Routing Entropy which is a parameter representing the transmission state of each node by taking into account the power left and the distance to the sink node. Then, it is proved that the problem of route thinking about Opportunistic Routing Entropy is shown to be NP-hard. So the protocol, ACO-TDOP, is proposed. At last, numerical results confirm that the ACO-TDOP is energy conservative and throughput gainful compared with other two existing routing protocols, and show that it is efficacious to analyze and uncover fundamental of message transmission with Opportunistic Routing in wireless network using the second law of thermodynamics.

Loading Localization by Small-Diameter Optical Fiber Sensors

Structural health monitoring(SHM)in service has attracted increasing attention for years.Load localization on a structure is studied hereby.Two algorithms,i.e.,support vector machine(SVM)method and back propagation neural network(BPNN)algorithm,are proposed to identify the loading positions individually.The feasibility of the suggested methods is evaluated through an experimental program on a carbon fiber reinforced plastic laminate.The experimental tests involve in application of four optical fiber-based sensors for strain measurement at discrete points.The sensors are specially designed fiber Bragg grating(FBG)in small diameter.The small-diameter FBG sensors are arrayed in 2-D on the laminate surface.The testing results indicate that the loading position could be detected by the proposed method.Using SVM method,the 2-D FBG sensors can approximate the loading location with maximum error less than 14 mm.However,the maximum localization error could be limited to about 1 mm by applying the BPNN algorithm.It is mainly because the convergence conditions(mean square error)can be set in advance,while SVM cannot.

Dynamic Load Balancing with Overlay-Based Reconfiguration for Wireless Sensor Networks

Wireless sensor networks are characterized by multihop wireless links and resource constrained nodes. In terms of data collection and forwarding scheduling, this paper investigates the load balancing in sensor nodes and wireless link based on the performance of wireless sensor networks. Leveraging the property of dissimilarity distribution, a method to quantitatively evaluate the benefits of load balancing is presented, in order to access the profitability. Then a novel Dynamic Load Balancing of Overlay-based WSN (DLBO) algorithm has been put forward. In particular, the tradeoff between transferring ratio and the load imbalance among nodes is discussed. The load balancing method in this paper outperforms others based on balancing factor, different nodes number and data scales of applications. The proposed model and analytical results can be effectively applied for reliability analysis for other wireless applications (e.g., persistent data delivery is involved).

A Coverage-Aware Unequal Clustering Protocol with Load Separation for Ambient Assisted Living Based on Wireless Sensor Networks

Ambient Assisted Living(AAL) is becoming an important research field. Many technologies have emerged related with pervasive computing vision, which can give support for AAL. One of the most reliable approaches is based on wireless sensor networks(WSNs). In this paper, we propose a coverage-aware unequal clustering protocol with load separation(CUCPLS) for data gathering of AAL applications based on WSNs. Firstly, the coverage overlap factor for nodes is introduced that accounts for the degree of target nodes covered. In addition, to balance the intra-cluster and inter-cluster energy consumptions, different competition radiuses of CHs are computed theoretically in different rings, and smaller clusters are formed near the sink. Moreover, two CHs are selected in each cluster for load separation to alleviate the substantial energy consumption difference between a single CH and its member nodes. Furthermore, a backoff waiting time is adopted during the selection of the two CHs to reduce the number of control messages employed. Simulation results demonstrate that the CUCPLS not only can achieve better coverage performance, but also balance the energy consumption of a network and prolong network lifetime.

Research on Dynamic Clustering Routing Considering Node Load for Wireless Sensor Networks

Aiming at the problem that node load is rarely considered in existing clustering routing algorithm for Wireless Sensor Networks (WSNs), a dynamic clustering routing algorithm for WSN is presented in this paper called DCRCL (Dynamic Clustering Routing Considering Load). This algorithm is comprised of three phases including cluster head (CH) selection, cluster setup and inter-cluster routing. First, the CHs are selected based on residual energy and node load. Then the non-CH nodes choose a cluster by comparing the cost function of its neighbor CHs. At last, each CH communicates with base station by using multi-hop communication. The simulation results show that comparing with the existing one, the techniques life cycle and date volume of the network are increased by 30.7 percent and 29.8 percent respectively by using the proposed algorithm DCRCL.

Performance Analysis of an Enhanced Load Balancing Scheme for Wireless Sensor Networks

Research interest in sensor networks routing largely considers minimization of energy consumption as a major performance criterion to provide maximum sensors network lifetime. When considering energy conservation, routing protocols should also be designed to achieve fault tolerance in communications. Moreover, due to dynamic topology and random deployment, incorporating reliability into protocols for WSNs is very important. Hence, we propose an improved scalable clustering-based load balancing scheme (SCLB) in this paper. In SCLB scheme, scalability is achieved by dividing the network into overlapping multihop clusters each with its own cluster head node. Simulation results show that the proposed scheme achieves longer network lifetime with desirable reliability at the initial state compare with the existing multihop load balancing approach.

基于时域多参数信息融合与机器学习算法的井架钢结构损伤识别

为避免井架钢结构在作业过程中由结构损伤引发的安全隐患,将时域多参数信息融合与机器学习算法进行结合,基于井架钢结构位移响应信号提出了一种基于主成分分析和随机森林算法的井架钢结构损伤识别方法。利用加速度传感器提取在冲击载荷下井架钢结构的加速度响应信号,由加速度响应信号处理得到位移响应信号,并提取包含脉冲因子、裕度因子和峭度的3个时域特征;运用主成分分析法将3个特征融合成1个新的综合性时域特征,将原始信号中包含的大多数信息保留下来;将处理过的数据输入随机森林算法模型进行井架钢结构损伤识别,整个过程只需要采集损伤后的信号,不需要采集损伤前的信号。利用以上损伤识别模型对井架钢结构有限元模型进行仿真计算,同时结合ZJ70井架钢结构实验室模型的实验结果进行分析。分析结果表明:利用上述损伤识别方法可以准确高效地判断出井架钢结构单一或多处损伤,判断结果的正确率为90%以上。

碎冰与圆柱结构相互作用实验技术研究

针对难以开展冰载荷测量的实验难题,设计一套碎冰与圆柱结构相互作用的力学实验方案。制备非冻结模型冰,以微小力传感器为数据采集工具,利用波流水槽开展碎冰与圆柱结构相互作用的力学实验。实验测试不同冰速下的碎冰载荷,对冰载荷实验的现象,冰力特性以及数值精度进行分析。通过与文献结果对比,该实验方案测试所得冰载荷幅值吻合良好,呈现载荷分布的离散现象,展现碎冰与结构的翻转、旋转、堆积现象,为碎冰载荷的技术研究及分析预报奠定基础。

网络Sensor的总体设计与核心实现机制

研究了分布式入侵检测系统 (DIDS)的重要前端部件Sensor ,从设计原则和功能描述 ,到Sensor的层次 ,然后提出其总体结构。在总体结构下 ,着重剖析五大核心实现机制 :采集、检测、通讯。

基于电磁弹式索力传感器的悬索桥短吊索索力检测

采用传统索力测试方法进行短吊索索力测试的精度难以满足工程需求。本文以棋盘洲长江公路大桥悬索桥荷载试验为工程依托,提出基于磁弹原理及磁电效应的电磁弹式索力传感器检测吊索索力的方法,并与有限元分析结果以及频率法、应变法测试结果进行对比。结果表明,试验标定误差小于±2%,在荷载试验中,传统索力测试方法对吊索的测量误差偏大,采用电磁弹式索力传感器更为准确地测量了短吊索索力,解决了短吊索索力的测量难题。荷载试验的吊索索力测试结果表明,索力增量的测试值与分析值偏差小于±5%,实际索力的测试值与分析值偏差小于±4%。

传感器安装位置对负载敏感液压系统动态响应的影响

针对工程实践中出现的负载敏感系统响应迟滞故障,基于负载敏感系统的工作原理,提出传感器对系统响应的影响可能性。经过实验与分析,得到传感器在不同安装位置时的动态响应曲线,同时分析其影响机制和改进措施。最后,根据不同使用工况得到传感器的安装最优位置。

农田耕整载荷六维力传感器结构优化与解耦研究

针对农田耕整载荷大、测量精度低等问题,在经典十字梁结构基础上,设计了一种辐梁式六维力传感器,可同时测量力和力矩,通过仿真方法对传感器结构进行了优化,确定了应变梁长、宽、高分别为9、10、6 mm;分析了传感器结构在载荷下的应变能力,确定了应变片贴片位置。对传感器开展了静态标定试验,基于标定数据采用改进型XGBoost(Extreme gradient boosting)机器学习网络对力信号进行解耦,并与常规网络进行比对。试验结果表明,改进型XGBoost模型在X、Y、Z方向力和力矩6种加载方式的测试集决定系数R^(2)_(P)分别达到0.9804、0.9418、0.9434、0.9868、0.9969、0.9822,预测效果较好,避免了陷入局部最优解。改进型XGBoost模型在六维加载力、力矩的R^(2)_(P)、测试集平均绝对误差(MAEP)均明显优于随机森林模型、传统多元线性回归,相较于传统多元线性回归方式,六维加载力、力矩的R^(2)_(P)分别提升22.57%、20.99%、23.32%、26.27%、26.05%、18.72%。基于机器学习的解耦算法可明显减少耦合误差的影响,提高传感器的测量精度,为农机优化提供了技术支撑。

一种新型无磁传感磨机综合检测系统

为解决磨机功耗大、负荷难以预测等问题,提出一种基于无磁传感的球磨机综合检测系统。该系统利用无磁耦合传感技术监测磨机负荷,不受磨机内物料磁性影响,结合更能准确反映磨机真实负荷特性的低功耗滚筒筒壁振动检测单元,通过无线传输将振动数据发送给信号采集单元,解决滚筒筒壁振动检测系统取电难的问题。融合磨机的磨音采集数据,在本地边缘算法单元内借助深度学习对磨机负荷特性进行预测,并反馈给PLC控制器进行给料和加球等实时调节,实现系统的闭环控制,极大提升了磨机效率,稳定生产指标,显著降低系统能耗。该系统在某选矿厂的试用结果证实其对磨机负荷预测识别效果良好。

基于光纤传感器的大型风电机组叶片荷载在线监测方法

现阶段,风电机组得到深层次开发和运用,向低成本、高功率方向发展,机组风轮直径、扫琼面积不断增加,有效加快电力输送效率,满足社会的用电需求,但也提高运行隐患,极易出现叶片荷载不均匀的现象,影响大型风电机组的发电效果。该文以提高风电机组的发电稳定性为研究目标,着重阐述光纤传感器下大型风电机组叶片荷载在线监测系统,并简单论述叶片结构和受力分析,以及常见故障类型等内容,希望对相关研究工作有所参考。

一种阀厅升降平台车平台载荷分布不均衡报警装置

针对阀厅升降平台车应用中出现的载荷分布不均衡问题,设计一种实时监测并报警的装置。首先,选择适用于载荷分布检测的压力、位移传感器。其次,对传感器采集的信号进行处理,实现对载荷分布的实时监测和分析。最后,设计声光报警以满足户外作业场景需求。实验验证表明,该装置能够有效监测载荷分布情况,并在出现异常时及时发出警报,有助于保障设备和操作人员安全。

基于半固定分簇的无线传感器网络节能分簇路由算法

为了解决无线传感器网络中节点能耗不均衡和数据传输能耗大导致的网络生命周期短的问题,提出了基于半固定分簇的节能分簇路由算法。在节点部署完毕后对每个簇进行调整,保证每个簇的节点数相同,从而达到负载均衡的目的。在簇头选择阶段,主要考虑节点间距离以及节点的剩余能量;在数据传输阶段,算法根据节点的剩余能量、节点到基站的距离以及节点之间的距离构建了中继节点选择的优化模型,同时实现了均衡和降低能耗的目标;当网络运行一段时间后,由于簇间的剩余能量差异过大,再次对簇群进行优化,尽可能使得每个簇群能量接近;最后当簇头节点能量低于所设阈值时,再次对簇头进行轮换优化,以延长节点的工作时长。仿真结果表明,所提算法有效降低了节点能耗,延长了网络的生命周期。

集成于碳纤维复合材料的fsFBG响应特性研究

针对航空航天碳纤维复合材料结构健康监测需求,研究了飞秒激光逐点直写光纤光栅传感器(fsFBG)和碳纤维复合材料集成时的传感特性。在碳纤维复合材料层合板表面及层间布置fsFBG,对碳纤维复合材料层合板进行静态载荷和低速冲击载荷加载实验,系统分析了表面和不同层间fsFBG对载荷响应的敏感性和差异性,得到了fsFBG中心波长偏移量与加载距离和加载角度的对应关系。实验表明,表面粘贴的fsFBG对动静载荷的敏感度更高,在动静态载荷作用下,fsFBG中心波长偏移量随加载载荷的增大呈线性递增,而随加载距离的增加而逐渐减小;fsFBG具有较好的载荷-方向敏感特性,传感器的响应灵敏度随加载夹角增大逐渐提高。