State-centric programming for sensor-actuator network systems

Distributed embedded systems such as wireless sensor and actuator networks require new programming models and software tools to support the rapid design and prototyping of sensing and control applications. Unlike centralized platforms and Web-based distributed systems, these distributed sensor-actuator network (DSAN) systems are characterized by a massive number of potentially failing nodes, limited energy and bandwidth resources, and the need to rapidly respond to sensor input. We describe a state-centric, agent-based design methodology to mediate between a system developer's mental model of physical phenomena and the distributed execution of DSAN applications. Building on the ideas of data-centric networking, sensor databases, and proximity-based group formation, we introduce the notion of collaboration groups, which abstracts common patterns in application-specific communication and resource allocation. Using a distributed tracking application with sensor networks, we'll demonstrate how state-centric programming can raise the abstraction level for application developers.     

Quality-aware data abstraction layer for collaborative 2-tier sensor network applications

This paper presents PRIDE, a novel data abstraction layer for collaborative 2-tier sensor network applications. PRIDE, more specifically, targets distributed real-time applications, in which multiple collaborative mobile devices have to analyze a global situation by collecting and managing data streams from massive underlying sensors. PRIDE at these devices hides the details of underlying sensors and provides transparent, timely, and robust access to global sensor data under highly dynamic and unpredictable environments of emerging sensor network applications. For transparent and efficient sharing of global sensor data, a model-based predictive replication mechanism is proposed and integrated into a conventional data management system that supports diverse types of spatial and temporal queries. In addition, for robust and timely query processing, the predictive replication scheme is extended to the problem of guaranteeing Quality-of-Service (QoS) by introducing feedback control of the accuracy bounds of models. We show the viability of the proposed solution by implementing and evaluating it on a 2-tier sensor network testbed, emulating collaborative search-and-rescue tasks with realistic workloads. Our evaluation results demonstrate that PRIDE can achieve timely sensor data sharing among a large number of devices in a highly robust and controlled manner.     

Observer‐based cooperative distributed fault‐tolerant model predictive control with imperfect network communication and asynchronous measurements

Intermittent actuator and sensor faults tolerant are simultaneously considered in a distributed control system with imperfect communication network. The asynchronous measurements of different output variables in one sampling period are synchronized through a novel two‐stage model‐based projection method. Different from centralized control network, in both layer‐to‐layer and in‐layer communication, the packet delay, loss and disordering are corrected by the predicted data from model predictive control. Moreover, a completely distributed state observer is established for both system states and sensor faults problem with bounded noise uncertainties. For the intermittent actuator faults, actuator plug‐and‐play design methods based on model predictive control has been introduced, making the actuator faults estimation omitted. The distributed stability conditions are derived for the proposed fault‐tolerant controller, and the online feasibility is explained in detail. Numerical simulation is given to verify the design procedure.     

Multi-objective optimization for coverage control in wireless sensor network with adjustable sensing radius

In this paper, the problem of maintaining sensing coverage by keeping a small number of active sensor nodes and a small amount of energy consumption in a wireless sensor network is studied. As opposed to the uniform sensing model previously, we consider a large number of sensors with adjustable sensing radius that are randomly deployed to monitor a target area. A novel coverage control scheme based on elitist non-dominated sorting genetic algorithm (NSGA-II) is proposed in a heterogeneous sensor network. By devising a cluster-based architecture, the algorithm is applied in a distributed way. Furthermore, an ameliorated binary coding is addressed to represent both sensing radius adjustment and sensor selection. Numerical and simulation results validate that the procedure to find the optimal balance point among the maximum coverage rate, the least energy consumption, as well as the minimum number of active nodes is fast and effective.     

A smart node architecture for adding mobility to wireless sensor networks

Adding a few mobile nodes into the conventional wireless sensor networks can greatly improve the sensing and control capabilities of the networks and can help researchers solve many challenges such as network deployment and repair. This paper presents an enhanced node architecture for adding controlled mobility to wireless sensor networks. The structural model, the power model and the networking model of the proposed mobile node have been built respectively for better node control. And it provides a novel robotic platform for experimental research in hybrid sensor networks or other distributed measurement and control systems. A testbed has finally been created for validating the basic functions of the proposed mobile sensor node. The results of a coverage experiment show that the mobile node can provide additional support for network coverage and can ensure that the sensor network will work properly in undesirable environments.     

基于马尔可夫链的无线传感器网络分布式调度方法

能量效率是无线传感器网络(Wireless sensor network, WSN)研究中的核心问题之一. 当节点采用电池供电时, 有限的能量限制了网络的生存周期, 从而对无线传感器网络的大规模应用提出了挑战. 本文基于马尔可夫链, 提出了一种实用的、协作分布式的调度方法, 并从理论上证明了该方法的收敛性. 该方法不仅可对节点的休眠/唤醒进行调度, 还可以对节点数据发送进行调度以减少数据冲突的发生. 仿真实验结果表明, 该方法能够有效地减少节点能量的消耗, 且对其他网络性能的影响较小.     

利用主动网技术实现高效的分布式网络管理

随着网络规模的迅速扩大，传统的集中式的网络的缺陷已经凸现，一个灵活高效的网络管理平台应该是分布式，可编程的，文章探讨了把主动网技术应用到网络管理中来实现高效的分布式网络管理，提出了一种新的网络体系结构。     

面向主动配电网实时优化调度的图强化学习方法

主动配电网的新能源、储能等能源形式可以有效提高运行的灵活性和可靠性, 同时新能源和负荷也给配电网带来了双重不确定性, 致使主动配电网的实时优化调度决策维度大、建模精度差. 针对这一问题, 本文提出结合图神经网络和强化学习的图强化学习方法, 避免对复杂系统的精准建模. 首先, 将实时优化调度问题表述为马尔可夫决策过程, 并将其表述为动态序贯决策问题. 其次, 提出了基于物理连接关系的图表示方法, 用以表达状态量的隐含相关性. 随后, 提出图强化学习来学习将系统状态图映射到决策输出的最优策略. 最后, 将图强化学习推广到分布式图强化学习. 算例结果表明, 图强化学习在最优性和效率方面都取得了更好的效果.     

无线传感器网络测试技术与测试平台研究

随着无线传感器网络应用研究的不断深入,通过实际传感器节点建立网络平台进行网络测试越来越受到人们的重视。本文对无线传感器网络测试技术和测试平台进行了探讨,并分别对搭建测试平台中的三个关键问题：量化评估节点度网络的状态信息、监视控制节点网络行为、反映大规模网络应用环境,以度解决这三个问题的技术方案进行了介绍和讨论。为无线传感器网络平台的实际设计工作提供了指导和借鉴。     

网络管理的多agent范型

网络管理系统是大规模的分布式软件系统 ,伸缩性和灵活性是今天的网络管理技术面临的两大难题 .软件 a-gent为这些难题提供了出色的解决方法 .本文首先指出当前网络管理中存在的问题 ;在此基础上 ,提出基于多 agent的网络管理结构 ;为了证明其技术可行性 ,专门建立了基于 agent的网络流量管理实验系统 .对该系统的评估证明了软件agent非常适合于开发分布式网络管理系统 ,具有实时性高、可扩充性好、自治能力强的特点 ,而且与传统系统相比 ,这种系统的建立、修改和升级更加经济     

大规模网络安全态势评估系统

在大规模网络安全事件应急响应过程中,一个网络安全态势评估系统可以起到很好的辅助决策作用。提出了一种计算网络安全危害指数的方法,并在这种方法基础上设计实现了一个大规模网络安全态势评估系统。该系统通过对网络安全事件的模拟重放,对网络安全状况进行评估,给出网络整体的安全危害指数,并提出针对安全事件的响应控制策略。系统运行结果表明,这种安全态势评估的方法针对大规模网络安全行为是有效的。     

基于数据聚合的无线传感器网络拓扑发现算法

针对传感器网络能源有限的特性,提出了一种基于数据聚合的拓扑发现算法。根据在聚合节点（sink）收集到网络内部节点报文接收或丢失的情况,通过发现网络中所有叶子节点到sink节点的数据传输路径,来推测网络的逻辑拓扑,不会增加网络负担。仿真实验表明：算法可以准确快速地推测传感器网络的拓扑,并且适合大规模传感网络的拓扑推测。     

基于确定性退火的移动传感器网络聚合算法

针对动态、异构的无线移动传感器网络拓扑控制问题,提出聚集的自组织无线传感器网络拓扑模型,并介绍分布式结点聚合算法。该算法采用确定性退火技术,同时考虑影响传感器性能的诸多因素。仿真实验结果表明,利用该算法形成的结点聚集规模适度,时间开销增长平缓,且具有良好的适应性和扩展性。     

Specifying and verifying requirements of real-time systems

An approach to specification of requirements and verification of design for real-time systems is presented. A system is defined by a conventional mathematical model for a dynamic system where application specific states denote functions of real time. Specifications are formulas in duration calculus, a real-time interval logic, where predicates define durations of states. Requirements define safety and functionality constraints on the system or a component. A top-level design is given by a control law: a predicate that defines an automation controlling the transition between phases of operation. Each phase maintains certain relations among the system states; this is analogous to the control functions known from conventional control theory. The top-level design is decomposed into an architecture for a distributed system with specifications for sensor, actuator, and program components. Programs control the distributed computation through synchronous events. Sensors and actuators relate events with system states. Verification is a deduction showing that a design implies requirements     

无线传感器和执行器网络控制系统设计与仿真

无线传感器和执行器网络通过无线网络(ZigBee)将传感器和执行器与控制器相连,完成分布式传感和执行任务。针对无线网络传输和被控对象延时的不良影响,首先详细介绍了基于TrueTime 2.0的无线网络控制系统在Windows 7和Matlab R2010b环境下的搭建,给出了系统的仿真模型。对控制器节点分别采用常规PID控制和模糊PID控制算法进行仿真研究。仿真结果表明,对于存在延时环节的无线网络控制系统,模糊PID控制可以取得较好的控制效果,系统鲁棒性较强。该研究对物联网智能家居系统的设计具有一定参考价值。     

光纤环网中建立数据传输模型的方法研究*

为了在光线环网中高效地传输数据,首先确定了所研究光纤环网的物理拓扑结构,是一种多信道单向环网,然后详细地阐述了在其中建立数据传输模型的步骤和方法,以及各个模块的流程图,最后在设计的实验平台上对模型进行了完整的测试,测试结果表明数据传输模型可以在光纤环网中高效且正确地运行。     

基于物联网的滑坡自动远程监测预警系统设计

针对滑坡预警的世界难题,提出了一种基于物联网（ IOT）的分布式数据实时采集模型,并根据数据量巨大的问题,建立了最优BP神经网络的预测模型。在滑坡实验台上进行了验证,实验表明：该算法具有计算量小,预测效果稳定的特点。     

Distributed network control for mobile multi-modal wireless sensor networks

A sensor network operates on an infrastructure of sensing, computation, and communication, through which it perceives the evolution of events it observes. We propose a fusion-driven distributed dynamic network controller, called MDSTC, for a multi-modal sensor network that incorporates distributed computation for in-situ assessment, prognosis, and optimal reorganization of constrained resources to achieve high quality multi-modal data fusion. For arbitrarily deployed sensors, a certain level of data quality cannot be guaranteed in sparse regions. MDSTC reallocates resources to sparse regions; reallocation of network resources in this manner is motivated by the fact that an increased density of sensor nodes in a region of interest leads to better quality data and enriches the network resilience. Simulation results in NS-2 show the effectiveness of the proposed MDSTC. ¹     

面向业务网络管理系统的通信模型的研究

主要针对基于主动网络的面向业务网管系统的具体通信需要,分析了应该具备的通信功能,设计了执行环境,提出了一种分布式的主动代码存储机制,构建了业务层和网络层的通信有限自动机,提出了符合业务管理和主动网络技术特点的通信模型。该通信模型在网管原型系统中得到了运用,从运用结果看它能够较好地进行主动代码的动态加载,能够提供基础的通信服务。