Sensor Network Design for Nonlinear Processes

This paper presents a method to design a cost-optimal nonredundant sensor network to observe all variables in a general nonlinear process. A mixed integer linear programming model was used to minimize the cost with data classification to check the observability of all unmeasured variables. This work is a starting point for designing sensor networks for general nonlinear processes based on various criteria, such as reliability and accuracy.

Cross Layer Design for Cooperative Transmission in Wireless Sensor Networks

Several protocols and schemes have been proposed to reduce energy consumption in Wireless Sensor Net-works (WSNs). In this paper we employ farcoopt, a cross layer design approach with the concept of coop-eration among the nodes with best farthest neighbor scheme to increase the Quality of Service (QoS), reduce energy consumption, increases performance and end-to-end throughput. We present cooperative transmission to connect previously disconnect parts of a network thus overcoming the separation problem of multi-hop network. We show that this approach improves connectivity over 50% compared to multi-hop approaches and reduces the number of nodes necessary to provide full coverage of an area up to 35%. Simulation results show that on increase of data rates i.e. packet the network life time increases in farcoopt as compared to tra-ditional multi hop approach. The result of this analysis is presented in this work.

A Contention-Based MAC and Routing Protocol for Wireless Sensor Network

Advance development of wireless technologies and micro-sensor systems have enabled Wireless Sensor Network (WSN) to emerge as a leading solution in many crucial sensor-based applications. WSN deploys numerous resource-constrained sensor nodes which have limited power supply, memory and computation capability in a harsh environment. Inefficient routing strategy results in degraded network performance in terms of reliability, latency and energy efficiency. In this paper, a cross-layer design, Contention-based MAC and Routing protocol is proposed, termed Contention/SNIR-Based Forwarding (CSBF) protocol. CSBF utilizes the geographical information of sensor nodes to effectively guide the routing direction towards destination node, thereby enhancing reliability. Furthermore, Signal-to-Noise-plus-Interference Ratio (SNIR) metric is used as a routing parameter to guarantee high quality link for data transmission. A Contention-Winner Relay scheme is utilized to reduce the delays caused by the contention procedure. Energy efficiency is also improved by introducing sleep mode technique in CSBF. The simulation work is carried out via OMNeT++ network simulator. The performance of CSBF is compared with other existing routing protocols such as AODV and DSDV in terms of packet delivery ratio (PDR), average end-to-end (ETE) delay and energy consumption per packet. Simulation results highlight that CSBF outperforms AODV and DSDV protocols in respect of PDR and energy efficiency. CSBF also has the most consistent overall network performance.

Cross Layered MAC Design for RF Energy Harvesting Sensor Network

The main research objective in wireless sensor networks (WSN) domain is to develop algorithms and protocols to ensure minimal energy consumption with maximum network lifetime. In this paper, we propose a novel design for energy harvesting sensor node and cross-layered MAC protocol using three adjacent layers (Physical, MAC and Network) to economize energy for WSN. The basic idea behind our protocol is to re-energize the neighboring nodes using the radio frequency (RF) energy transmitted by the active nodes. This can be achieved by designing new energy harvesting sensor node and redesigning the MAC protocol. The results show that the proposed cross layer CL_EHSN improves the life time of the WSN by 40%.

Low Power Transceiver Design Parameters for Wireless Sensor Networks

Designing low power sensor networks has been the general goal of design engineers, scientist and end users. It is desired to have a wireless sensor network (WSN) that will run on little power (if possible, none at all) thereby saving cost, and the inconveniences of having to replace batteries in some difficult to access areas of usage. Previous researches on WSN energy models have focused less on the aggregate transceiver energy consumption models as compared to studies on other components of the node, hence a large portion of energy in a WSN still get depleted through data transmission. By studying the energy consumption map of the transceiver of a WSN node in different states and within state transitions, we propose in this paper the energy consumption model of the transceiver unit of a typical sensor node and the transceiver design parameters that significantly influences this energy consumption. The contribution of this paper is an innovative energy consumption model based on simple finite automata which reveals the relationship between the aggregate energy consumption and important power parameters that characterize the energy consumption map of the transceiver in a WSN;an ideal tool to design low power WSN.

A CROSS-LAYER STRATEGY FOR COOPERATIVE DIVERSITY IN WIRELESS SENSOR NETWORKS

We investigate the problem of how to minimize the energy consumption in multi-hop Wireless Sensor Network (WSN),under the constraint of end-to-end reliability Quality of Seervice (QoS) requirement.Based on the investigation,we jointly consider the routing,relay selection and power allocation algorithm,and present a novel distributed cross-layer strategy using opportunistic relaying scheme for cooperative communication.The results show that under the same QoS requirement,the proposed cross-layer strategy performs better than other cross-layer cooperative communication algorithms in energy efficiency.We also investigated the impact of several parameters on the energy efficiency of the cooperative communication in WSNs,thus can be used to provide guidelines to decide when and how to apply cooperation for a given setup.

An Energy-Efficient Access Control Algorithm with Cross-Layer Optimization in Wireless Sensor Networks

This paper presents a wireless sensor network (WSN) access control algorithm designed to minimize WSN node energy consumption. Based on slotted ALOHA protocol, this algorithm incorporates the power control of physical layer, the transmitting probability of medium access control (MAC) layer, and the automatic repeat request (ARQ) of link layer. In this algorithm, a cross-layer optimization is preformed to minimizing the energy consuming per bit. Through theory deducing, the transmitting probability and transmitting power level is determined, and the relationship between energy consuming per bit and throughput per node is provided. Analytical results show that the cross-layer algorithm results in a significant energy savings relative to layered design subject to the same throughput per node, and the energy saving is extraordinary in the low throughput region.

Cross-layer Enhancement to Multi-hop Routing in Sensor Networks: an Empirical Study

Lossy link is one of the unique characteristics in random-deployed sensor networks. We envision that robustness and reliability of routing cannot be ensured purely in network layer. Our idea is to enhance the performance of routing protocol by cross-layer interaction. We modified mint protocol, a routing protocol in TinyOS and proposed an enhanced version of mint called PA-mint. A transmission power control interface is added to network layer in PA-mint. When routing performance of the current network is not satisfied, PA-mint monotonically increases the transmission power via the interface we added. PA-mint is able to connect orphan nodes and robust to node mobility or key nodes failure. In the case that automatic request retransmission is employed, the number of retransmissions can be reduced by PA-mint. Results from experiments show that PA-mint increases the reliability and robustness of routing protocol by cross-layer interaction.

Toward a Multi-Hop, Multi-Path Fault-Tolerant and Load Balancing Hierarchical Routing Protocol for Wireless Sensor Network

This paper describes a novel energy-aware multi-hop cluster-based fault-tolerant load balancing hierarchical routing protocol for a self-organizing wireless sensor network (WSN), which takes into account the broadcast nature of radio. The main idea is using hierarchical fuzzy soft clusters enabling non-exclusive overlapping clusters, thus allowing partial multiple membership of a node to more than one cluster, whereby for each cluster the clusterhead (CH) takes in charge intra-cluster issues of aggregating the information from nodes members, and then collaborate and coordinate with its related overlapping area heads (OAHs), which are elected heuristically to ensure inter-clusters communication. This communication is implemented using an extended version of time-division multiple access (TDMA) allowing the allocation of several slots for a given node, and alternating the role of the clusterhead and its associated overlapping area heads. Each cluster head relays information to overlapping area heads which in turn each relays it to other associated cluster heads in related clusters, thus the information propagates gradually until it reaches the sink in a multi-hop fashion.

Energy Efficient and QoS Aware Framework for Video Transmission over Wireless Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs), is a network of sensors, which are limited in terms of memory, computing, bandwidth, and battery lifetime. Multimedia transmission over WSN requires certain QoS guarantees such as huge amount of bandwidth, strict delay and lower loss ratio that makes transmitting multimedia is a complicated task. However, adopting cross-layer approach in WMSNs improves quality of service of WSN under different environmental conditions. In this work, an energy efficient and QoS aware framework for transmitting multimedia content over WSN (EQWSN) is presented, where packet, queue and path scheduling were introduced. It adapts the application layer parameter of video encoder to current wireless channel state, and drops less important packets in case of network congestion according to packet type. Finally, the path scheduling differentiates packets types/priority and route them through different paths with different QoS considering network lifetime. Simulation results show that the new scheme EQWSN transmits video quality with QoS guarantees in addition to prolonging network lifetime.

Essential Topics on Constructing WCDS-based Virtual Backbone in Wireless Sensor/Mesh Networks

Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.

基于多传感数据融合的室内空间适老化环境监测系统设计

针对当前多传感数据融合算法性能不够理想导致室内空间适老化环境监测效果较差的问题,提出一种改进的多传感数据融合算法。提出一种变长数据融合算法(VLDFA)来消除冗余数据,对蜻蜓优化算法(DA)进行改进,结合改进DA和改进BP神经网络(BPNN),构建多传感数据融合模型。结果显示,该模型的精度超过98%。在温度误差与湿度误差监测比较中,所提出的模型的温度误差平均值为0.34℃,优于另外2种模型,表明该模型的多传感数据融合效果较为良好,能够很好地调整老年人居住环境。

基于无线传感器网络节点的老人智慧鞋履设计

当前老人智慧鞋履的提醒程序多设定为单次结构,整体的提醒效率较低,为此提出基于无线传感器网络节点的老人智慧鞋履的设计与实践应用。根据当前测定,先进行传感器及无线传感网络节点接入多目标健康提醒程序的设计,进行实时数据采集与定点传输,设计多目标健康提醒程序,构建无线传感器网络节点老人鞋履总控系统,最终采用智能报警的方式完成智慧鞋履的设计。测试结果表明:针对选定的6名测试人员,结合制定的3个测试指令组,最终得出的智慧鞋履的响应时延均被较好地控制在0.3 s以下,说明此次在无线传感器网络节点原理的辅助下,所设计的老人智慧鞋履更加灵活、高效,应用效果更佳。

基于对称映射搜索策略的自适应金鹰算法及应用

金鹰优化算法(Golden Eagle Optimizer,GEO)是一种基于种群的元启发式算法,其模拟了金鹰的合作狩猎行为。针对GEO算法中存在的求解精度差和陷入局部最优等问题,文中提出了一种改进MERGEO(Mapped Elitist Reverse GEO)算法。在原算法基础上采用对称映射搜索策略、自适应精英策略和随机反向学习机制这3种方法平衡了算法的探索和开发阶段,获得了规避局部最优能力和较好的优化精度。在10个基准测试函数上对该算法进行独立策略有效性分析、可扩展性分析以及同其他算法的优化性能比较分析。实验结果表明,改进后的MERGEO算法具有较强的竞争力和良好的优化能力。将改进后的算法用于无线传感器网络的覆盖优化问题和压力容器设计问题研究,验证了其实际应用价值。

面向航天运载器的通用化无线传感网络设计方法

无线传感网络作为航天领域的一项新兴技术,凭其无缆化测量的显著优势,已成为航天运载器环境参数测量的重要手段。目前航天运载器上搭载的无线传感网络纷繁复杂,技术路线各异,难以有效提高产品的性能和可靠性。提出了一种面向航天运载器的通用化无线传感网络设计方法,重点介绍了通用化产品架构、设计要点、应用难点及发展思路,旨在提高产品性能及可靠性,最终形成性能分档、可靠性高的货架产品。

自动化仪表与传感器网络的协同优化设计与实现

文中讨论了自动化仪表与传感器网络的协同优化设计与实现,提高了系统的整体性能和效率。采用先进的算法和模型,实现了传感器布局的最优化,在确保数据采集的精确性与实时性的同时降低能耗,还优化了网络通信协议,以适应不同的工作环境和需求。实验结果显示,协同优化策略显著提高了自动化仪表系统的可靠性和传感器网络的数据处理能力,对工业自动化和智能监控系统的设计与优化提供了新的思路和方法。

信息收集中无人机节能轨迹设计与资源优化

为优化无线传感器网络(wireless sensor networks,WSN)中无人机(unmanned aerial vehicle,UAV)辅助信息收集系统的能量消耗,在综合考虑无人机飞行能耗和传感器节点上行数据传输能耗的基础上,提出了一种考虑链路间干扰的无人机轨迹和传感器功率分配联合优化算法。首先,基于实际约束构建了系统能耗最小化问题模型;然后,针对多约束优化问题的非凸性特征,采用块坐标下降法(block coordinate descent,BCD)将系统能耗最小化问题分解为固定无人机轨迹下的功率分配和固定功率分配下的无人机轨迹优化两个子问题,根据子问题的数学特征,采用凸近似法将非凸问题转化成可以求解的近似凸优化问题,通过对两个子问题的交替迭代优化,得到原非凸问题的近似次优解;最后,通过仿真实验验证了所提算法的可行性和有效性。结果表明:所提算法最大可使系统能量消耗降低22%,明显优于对比算法;且随着传感器节点数量的增加,所提算法的优势更加明显。研究结果为WSN中的信息收集提供了一种系统能耗优化思路,即在有限提高无人机飞行能耗的基础上,有效降低系统的能量消耗。

基于无线传感网络的化工行业实验室信息管理系统设计

常规的化工行业实验室信息管理系统以模块化管理为主,在系统中增加了大量的运算,造成了系统的运行负担。因此,设计了基于无线传感网络的化工实验室信息管理系统。基于无线传感网络建立实验室信息管理数据库,将相同属性的实验室信息整合到一个数据类别中,依靠字段、数据类型管理数据,从而满足系统高效率运行的需求。采用系统测试,验证了该系统的运行性能更佳,能够应用于实际生活中。

Accurate energy model for WSN node and its optimal design

With the development of CMOS and MEMS technologies, the implementation of a large number of wireless distributed micro-sensors that can be easily and rapidly deployed to form highly redundant, self-configuring, and ad hoc sensor networks. To facilitate ease of deployment, these sensors operate on battery for extended periods of time. A particular challenge in maintaining extended battery lifetime lies in achieving communications with low power. For better understanding of the design tradeoffs of wireless sensor network （WSN）, a more accurate energy model for wireless sensor node is proposed, and an optimal design method of energy efficient wireless sensor node is described as well. Different from power models ever shown which assume the power cost of each component in WSN node is constant, the new one takes into account the energy dissipation of circuits in practical physical layer. It shows that there are some parameters, such as data rate, carrier frequency, bandwidth, Tsw, etc, which have a significant effect on the WSN node energy consumption per useful bit （EPUB）. For a given quality specification, how energy consumption can be reduced by adjusting one or more of these parameters is shown.

基于无线传感网络的机房环境监控系统

当前,机房环境监控系统的数据库多设定为目标式,这种模式会导致监控效率较低、误报率增加。为了缓解这一情况,文章提出基于无线传感网络的机房环境监控系统。根据当前的测试需求及标准的变化,设定无线监控传感节点装置,搭建网关,完成系统硬件的设计;在系统硬件的基础上构建无线传感网络下ZigBee协议栈,采用多层级的方式,设计多层级数据库,提升整体的监控效率,完成对系统软件的设计。系统测试结果表明:针对选定的4个测试周期,所设计系统经过3个测试阶段,最终得出的监控系统误报率被较好地控制在1.5%以下,说明在无线传感网络的辅助下,所构建的机房环境监控系统稳定、高效,针对性强,具有实际的应用价值。