Huge Capacity Fiber-Optic Sensing Network Based on Ultra-Weak Draw Tower Gratings

This paper reviews the work on huge capacity fiber-optic sensing network based on ultra-weak draw tower gratings developed at the National Engineering Laboratory for Fiber Optic Sensing Technology （NEL-FOST）, Wuhan University of Technology, China. A versatile drawing tower grating sensor network based on ultra-weak fiber Bragg gratings （FBGs） is firstly proposed and demonstrated. The sensing network is interrogated with time- and wavelength-division multiplexing method, which is very promising for the large-scale sensing network.

Energy Efficient Social Routing Framework for Mobile Social Sensing Networks

Mobile social sensing network is one kind of emerging networks in which sensing tasks are performed by mobile users and sensing data are shared and collected by leveraging the intermittent inter-contacts among mobile users. Traditional ad hoc routing protocols are inapplicable or perform poorly for data collection or data sharing in such mobile social networks because nodes are seldom fully connected. In recent years, many routing protocols （especially social-based routing） are proposed to improve the delivery ratio in mobile social networks, but most of them do not consider the load of nodes thus may lead to unbalanced energy consumption among nodes. In this paper, we propose a simple Energy Efficient framework for Social-based Routing （EE-SR） in mobile social sensing networks to balance the load of nodes while maintaining the delivery ratio within an acceptable range by limiting the chances of forwarding in traditional social-based routing. Furthermore, we also propose an improved version of EE-SR to dynamically adjust the controlling parameter. Simulation results on real-life mobile traces demonstrate the efficiency of our proposed framework.

Formation Control of Underwater Mobile Sensing Networks

Formation control is essential for an underwater mobile sensing network(UMSN) ,and an ad hoc network which wirelessly connects underwater vehicles of sensing and/or observing types via acoustic communications,to fulfill mobile sensing tasks.The problem of formation control for a UMSN with varying topology is studied in this paper.The methodology of synthesizing distributed formation controller which stabilizes a UMSN with varying topology is proposed on the basis of the stability analysis of linear time-varying systems.

Convergence analysis of distributed Kalman filtering for relative sensing networks

We study the distributed Kalman filtering problem in relative sensing networks with rigorous analysis.The relative sensing network is modeled by an undirected graph while nodes in this network are running homogeneous dynamical models. The sufficient and necessary condition for the observability of the whole system is given with detailed proof. By local information and measurement communication, we design a novel distributed suboptimal estimator based on the Kalman filtering technique for comparison with a centralized optimal estimator. We present sufficient conditions for its convergence with respect to the topology of the network and the numerical solutions of n linear matrix inequality（LMI） equations combining system parameters. Finally, we perform several numerical simulations to verify the effectiveness of the given algorithms.

A Low-Cost Testbed of Underwater Mobile Sensing Network

Comprised by a swarm of acoustically linked and cooperative autonomous underwater vehicles(AUVs) with onboard sensors,an underwater mobile sensing network(UMSN) will be a complementary means to fixed observatory networks,e.g.seafloor observatory networks and moored buoy arrays.It has obvious advantages over a single large AUV in higher efficiency due to parallel observation,stronger robustness to vehicle failures and lower cost.Although an UMSN can be viewed as a counterpart of wireless mobile sensing networks for air and terrestrial applications,it is much more challenging due to poor performance of underwater acoustic communication, poor performance of underwater positioning and high degree of uncertainty in vehicle dynamics and underwater environment.In order to verify key technologies involved in an UMSN,e.g.cooperation of multi-AUVs based on acoustic communication,a low cost testbed has been developed for experimental study.The design of both hardware and software is introduced.Also the results of a functional test for verification of the effectiveness of the testbed are presented.

Theoretical and experimental study on white light interferometric sensing network with double-ring topology

A white-light interferometric fiber-optic sensing network based on the double-ring topology is demonstrated,which can be applied to the measurements of quasi-distributed strain and temperature in a smart structure.In order to increase the multiplexing capacity,decrease the measurement cost of each sensor,and improve the ability of reliability of the sensor network,a double-port interrogating technology was used.The double-ring fiber optical sensing network based on the space division multiplexing(SDM)is further developed.The low coherent multiplexing principle in the double-ring network structure is analyzed.Based on the optical path matching condition of SDM,the intensity characteristic of the interference signal in the sensor is deduced.The characteristics of the double-ring sensing network connecting 9 sensors and its property of robust resisting destruction are verified by experiments,and the results are analyzed and discussed.

Special issue on Networked sensing,decision-making and control

Networked sensing and control has attracted significant interest in recent years due to its wide applications. For example, sensor networks, especially wireless sensor networks, have found important applications in environmental monitoring, agriculture, building and industrial automation, machine condition monitoring, intelligent transportation systems, health care, surveillance, and defense. On the other hand, due to the flexibility and significant COSt-saving,

2007 IEEE International Conference on Networking,Sensing and Control

Conference Theme-Anti-Crime Networking and Systems The 2007 IEEE International Conference on Networking,Sensing and Control will be held in London. The main theme of the conference is anti-crime networking and critical infrastructure.The area of anti- crime networking and critical infrastructure is a fusion of a number of research areas in networking, sensing,human factors,artificial intelligence,operational research,and systems control theory. However,the real challenge is to design anti-crime networking and systems from a holistic perspective; taking into account technical,organizational as well as contextual complexity.A system engineering approach is required to address new problems of this challenging and promising area.This conference will provide a remarkable opportunity for the academic and industrial community to address new challenges and share solutions,and discuss future research directions.It will feature plenary speeches, industrial panel sessions,funding agency panel sessions,interactive sessions,and invited/special sessions.Contributions are expected from academia,industry,EPSRC,EU,DTI,and MoD.Technical topics of the conference include but are not limited to:

A Secure-Efficient Data Collection Algorithm Based on Self-Adaptive Sensing Model in Mobile Internet of Vehicles

Existing research on data collection using wireless mobile vehicle network emphasizes the reliable delivery of information.However,other performance requirements such as life cycle of nodes,stability and security are not set as primary design objectives.This makes data collection ability of vehicular nodes in real application environment inferior.By considering the features of nodes in wireless IoV,such as large scales of deployment,volatility and low time delay,an efficient data collection algorithm is proposed for mobile vehicle network environment.An adaptive sensing model is designed to establish vehicular data collection protocol.The protocol adopts group management in model communication.The vehicular sensing node in group can adjust network sensing chain according to sensing distance threshold with surrounding nodes.It will dynamically choose a combination of network sensing chains on basis of remaining energy and location characteristics of surrounding nodes.In addition,secure data collection between sensing nodes is undertaken as well.The simulation and experiments show that the vehicular node can realize secure and real-time data collection.Moreover,the proposed algorithm is superior in vehicular network life cycle,power consumption and reliability of data collection by comparing to other algorithms.

Optical SDMA for applying compressive sensing in WSN

In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view（FOV）, fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes＇ laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens＇ FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna＇s qualitative feasibility is validated.

Resource Allocation for Uplink CSI Sensing Report in Multi-User WLAN Sensing

Sensing in wireless local area network(WLAN) gains great interests recently. In this paper we focus on the multi-user WLAN sensing problem under the existing 802.11 standards. Multiple stations perform sensing with the access point and transmit channel state information(CSI)report simultaneously on the basis of uplink-orthogonal frequency division multiple access(OFDMA). Considering the transmission resource consumed in CSI report and the padding wastage in OFDMA based CSI report, we optimize the CSI simplification and uplink resource unit(RU)allocation jointly, aiming to balance the sensing accuracy and padding wastage performances in WLAN sensing. We propose the minimize padding maximize efficiency(MPME) algorithm to solve the problem and evaluate the performance of the proposed algorithm through extensive simulations.

The Modals as Pragmatic Softening Devices： Evidence From Late Modern English Grammar and Manner Books

In this research, the author considers the evidence provided by a corpus of Late Modem English grammars for our understanding of the development of the modals as politeness markers. It is possible to see how the modals and their accompanied senses are explained in an official （and often either prescriptive or proscriptive） perspective. This is another aspect which cannot be ascertained from the usage based on corpora which seem to be popular as sources of evidence in historical pragmatics. In this sense, this research brings some novel perspective to this aspect of academic study. It is possible to notice that the significations involves concept or senses which extend across a semantic--pragmatic domain which includes politeness. We can see that certain softening senses are key elements to mark polite usage. The main data used come from the descriptions of the modal auxiliary verb in a corpus of grammar books from the period. Usage and manner books are also consulted as a secondary resource. The manner book in particular is quite helpful for our understanding of how linguistic politeness was regarded at the time. Such texts also help us to find a certain network of senses which are related to polite expressions.

Multi-Wavelength Ultra-Weak Fiber Bragg Grating Arrays for Long-Distance Quasi-Distributed Sensing

Fiber Bragg grating(FBG)array,consisting of a number of sensing units in a single optical fiber,can be practically applied in quasi-distributed sensing networks.Serious signal crosstalk occurring between large-serial of identical FBGs,however,has limited the further increase in the number of sensing units,thus restricting applications only for short-distance sensing networks.To reduce the signal crosstalk,we design two novel types of 10-kilometer-long FBG arrays with 10000 equally spaced gratings,written on-line using a customized grating inscription system,which is affiliated to a drawing tower.Main factors causing signal crosstalk,such as spectral shadowing and multiple reflections,are firstly investigated in theory.Consistent with the theoretical findings,experimental results are proving that ultra-weak(the reflectivity of—40 dB)and multi-wavelength gratings of a number more than 10000 can be readily identified,with satisfied low crosstalk.The maximum attenuation of grating signal and minimum signal-to-noise ratio(SNR)in a single-wavelength array are 10.69 dB and 5.62 dB,respectively.As a comparison,by increasing the number of central wavelengths to three,the attenuation can be effectively reduced to 5.54dB and the minimum SNR has been improved to 8.14 dB.The current study significantly enhances the multiplexing capacity of FBG arrays and demonstrates promising potentials for establishing large-capacity quasi-distributed sensing networks.

A Reducing Iteration Orthogonal Matching Pursuit Algorithm for Compressive Sensing

In recent years, Compressed Sensing（CS） has been a hot research topic. It has a wide range of applications, such as image processing and speech signal processing owing to its characteristic of removing redundant information by reducing the sampling rate. The disadvantage of CS is that the number of iterations in a greedy algorithm such as Orthogonal Matching Pursuit（OMP） is fixed, thus limiting reconstruction precision.Therefore, in this study, we present a novel Reducing Iteration Orthogonal Matching Pursuit（RIOMP） algorithm that calculates the correlation of the residual value and measurement matrix to reduce the number of iterations.The conditions for successful signal reconstruction are derived on the basis of detailed mathematical analyses.When compared with the OMP algorithm, the RIOMP algorithm has a smaller reconstruction error. Moreover, the proposed algorithm can accurately reconstruct signals in a shorter running time.

Sensorless Sensing with WiFi

Can WiFi signals be used for sensing purpose？ The growing PHY layer capabilities of WiFi has made it possible to reuse WiFi signals for both communication and sensing. Sensing via WiFi would enable remote sensing without wearable sensors, simultaneous perception and data transmission without extra communication infrastructure, and contactless sensing in privacy-preserving mode. Due to the popularity of WiFi devices and the ubiquitous deployment of WiFi networks, WiFi-based sensing networks, if fully connected, would potentially rank as one of the world＇s largest wireless sensor networks. Yet the concept of wireless and sensorless sensing is not the simple combination of WiFi and radar. It seeks breakthroughs from dedicated radar systems, and aims to balance between low cost and high accuracy, to meet the rising demand for pervasive environment perception in everyday life. Despite increasing research interest, wireless sensing is still in its infancy. Through introductions on basic principles and working prototypes, we review the feasibilities and limitations of wireless, sensorless, and contactless sensing via WiFi. We envision this article as a brief primer on wireless sensing for interested readers to explore this open and largely unexplored field and create next-generation wireless and mobile computing applications.