Delay-Constrained Mobile Energy Charging in Wireless Sensor Networks

为了延长无线传感网的生存期,基于可充电的移动设备,研究设计了一种无线传感网中移动式能量补充的方法,移动节点可以在为传感器节点补充能量的同时收集数; 据.首先,通过将无线传感器网络监测区域分割为大小相同的子区域,该子区域内的节点组成一个簇;其次,以一个簇内的总能量为计算依据,设计移动节点的路径; 生成算法以确定能量高效的移动路线;最后,使用10种不同的随机网络拓扑图进行了仿真实验,以节点移动速度和时延为限制条件分别得到了对比数据.结果表明; ,本文提出的算法与NJNP( nearest-job-next with preemption)算法相比在时延相同的条件下( 800; s),生存期提升了6 000 s左右,在节点速度5 m/s条件下生存期提升了将近14 000; s.证明本文所提方法有效地提高了充电效率,延长了网络的生存期,可用于大规模的无线传感器网络.In order to prolong the lifetime of wireless sensor networks by using; energy-rechargeable mobile devices,this paper designs a mobile energy; replenishment method wherein a mobile element gathers data and recharges; sensors simultaneously. Firstly,the whole sensor network is divided into; several sub-regions equally and the sensors in each sub-region are; formed into a cluster. Secondly, considering the energy in a whole; cluster,the mobility path is designed to find the energy-efficient; mobile trace of the mobile element. Finally,in the simulation; experiment,we used ten different random network topologies to show the; comparisons with extensive simulation experiments under different; velocities and deadlines. The results indicate that the proposed; algorithm increases lifetime by approximately 6 000 s compared with; Nearest-Job-Next with Pre-emption( NJNP) under the deadline of 800 s.; Moreover,the proposed algorithm increases lifetime by approximately 14; 000 s compared with NJNP at velocity of 5 m/s. Thus,the proposed; algorithm can improve recharging efficiency and prolong the lifetime of; wireless sensor networks,which can be used in large-scale sensor; networks.国家自然科学基金资助项目; 福建省高等学校杰出青年科研人才培育计划资助项

Survey on Connectivity with Mobile Elements in WSNs

节点连通性是无线传感器网络研究的热点问题之一,然而由于节点能量耗尽、硬件故障以及通信链路失效等问题的存在,造成网络分割,因此如何确保网络连通成为; 无线传感器网络亟待解决的关键性问题.近年来,一个新的研究趋势是通过引入计算能力较强且能量较为充足的移动性节点来进行连通控制,提高无线传感器网络的; 整体性能.本文对目前利用移动性节点的主流连通控制方法进行了充分调研,通过对这些方法的详细分类和比较,归纳了移动式连通控制的各类方法的特点,分析了; 这些方法的性能和适用范围,总结了研究中存在的主要问题与挑战,并指出了未来可能的研究方向.The connectivity of sensors is one of the main research problems in; wireless sensor networks (WSNs).Data can be forwarded through connected; sensor nodes.However,becauseof energy depletion,hardware failure and; communication link failure,the network may be partitioned.How to; guarantee the connectivity becomes an urgent issue in wireless sensor; networks.Traditional work usually focuses on maximizing the connectivity; with minimum sensors.In recent years,a new research trend is to utilize; mobile elements for connectivity control.Since the mobile element is; more powerful than normal sensors,it improves the performance of many; aspectsin wireless sensor networks.In this paper,we makea comprehensive; investigation about the current major connectivity control methods with; mobile elements.We first summarize the characteristics of mobile; topology control methods via a new classification.Based on the; classification,these methods are compared to each other according to a; serial parameters.Finally,we analyze the performances and the; application scopes of these methods,summarize the main problems,and; point out the future research directions.国家"九七三"重点基础研究发展计划项目; 国家科技支撑计划项目; 国家自然科学基金项目; 福建省科技计划重点项目; 福建省自然科学基金计划项

Survey on Coverage Control with Mobile Elements in Wireless Sensor Networks

在无线传感器网络中,节点能量限制、硬件以及通信链路故障等问题,造成网络空洞的产生且影响了网络的正常运作,因此如何确保网络覆盖率成为传感器网络中需; 要解决的重要问题.近年来,通过引入移动节点来进行覆盖控制,提高传感器网络的覆盖率成为一个新的研究趋势.本文通过充分调研利用移动节点进行网络覆盖控; 制的方法,并对其进行了分类和比较,归纳了移动式网络覆盖的各种方法的特点,分析这些方法的性能和适用范围,总结存在的主要问题,并指出未来的研究方向.Due to the existence problems of energy depletion,hardware failure and; communication link failure and so on,which causes network holes and; affects the normal network operation. The insurance of coverage becomes; an urgent issue in wireless sensor networks. In recent years, a new; research trend is to utilize mobile nodes for coverage control, which; increases the coverage of wireless sensor networks. In this paper, we; have a comprehensive investigation about the current major topology; control methods with mobile nodes,and summarize the characteristics of; mobile topology control methods via classification and comparison of; these methods. Finally,we analyze the performances and the application; scopes of these methods, summarize the main problems,and point out the; future research directions.国家自然科学基金重点项目; 国家科技支撑计划项目; 国家自然科学基金项目; 福建省科技计划重点项

Industrial security situation prediction model based on LSTM-DNN

态势预测对于感知工控系统中的安全风险有着重要的作用。传统的态势预测模型往往会忽略工控系统中态势要素的时序性，难以准确对系统的安全态势进行预测。因此本文提出一种基于LSTM-DNN的工业网络安全态势预测模型，以提高传统态势预测模型的精确度。首先从海量数据中选取出与系统态势强相关的态势要素；接下来利用LSTM对提取的态势要素进行预测，得到未来的态势要素链；最后将提取出的态势要素链送入DNN模型中，预测系统未来的安全态势。实验表明，相较于传统的网络安全态势预测模型，该模型框架能够有效地预测未来的态势值；相比于其它算法，所提出的算法具有较高的预测精度。</p

Electrodeposition of RuO2 Layers on TiO2 Nanotube Array toward CO2 Electroreduction

传统上，RuO2/TiO2复合电极制备是通过在TiO2/Ti基体上多次涂覆含Ru前驱体溶液和随后热分解（TD）来实现的. 为克服上述方法中Ru用量大和利用率低之不足, 本工作主要基于循环伏安法（CV）在TiO2纳米管阵列（TNA）上电沉积RuO2制备RuO2CV/TNA复合电极. SEM、GIXRD和CV结果表明， 电沉积的RuO2为无定型结构, 所制备电极中的Ru用量约为传统的RuO2TD/TNA电极中Ru用量的1/30. 尽管两电极催化CO2还原产物的法拉第效率接近, 但是RuO2CV/TNA电极比RuO2TD/TNA电极展示了更高的还原电流, 较正的初始还原电位和更好的稳定性. 与磷酸盐缓冲溶液中电还原CO2相比，RuO2CV/TNA电极在0.1 mol&bull;L-1 KHCO3中电还原CO2除生成更高法拉第效率的甲酸根和甲烷外，还检测到CO的生成.RuO2/TiO2 composite materials have multitude of electrocatalytic applications including but not limited to CO2 reduction reaction (CO2RR). RuO2/TiO2 electrodes were previously prepared by repetitive coating and thermal decomposition (TD) of a Ru(III) precursor solution on Ti substrate. In this work, electrochemical potential cycling is applied to deposit amorphous RuO2 (&alpha;-RuO2) layers onto TiO2 nanotube array (TNA) (RuO2CV/TNA) preformed on Ti foil. SEM, GIXRD, and voltammetry are applied to characterize the structures of the resulting RuO2CV/TNA. Ru loading on the RuO2CV/TNA electrode is ca. 1/30 of that on the conventional RuO2TD/TNA electrode. Although both electrodes yield similar faradaic efficiencies (FEs) for the reduction products, the RuO2CV/TNA electrode displays a much higher reduction current, a more positive initial reduction potential and a better durability than the RuO2TD/TNA one. In addition to higher FEs for formate and CH4, the RuO2CV/TNA electrode yields the product of CO for the CO2RR in 0.1 mo&bull;lL-1 KHCO3, which is not available in a PBS solution with pH 7.This work is supported by the 973 Program (No. 2015CB932303) of MOST and NSFC (No. 21473039).This work is supported by the 973 Program (No. 2015CB932303) of MOST and NSFC (No. 21473039).作者联系地址：复旦大学化学系，能源材料化学协同创新中心，上海市分子催化与功能材料表面重点实验室，上海 200433Author's Address: Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Fudan University, Shanghai 200433, China通讯作者E-mail：[email protected]