Wireless measurement system for structural health monitoring with high time synchronization accuracy

Structural health monitoring (SHM) systems have excellent potential to improve the regular operation and maintenance of structures. Wireless networks (WNs) have been used to avoid the high cost of traditional generic wired systems. The most important limitation of SHM wireless systems is time-synchronization accuracy, scalability, and reliability. A complete wireless system for structural identification under environmental load is designed, implemented, deployed, and tested on three different real bridges. Our contribution ranges from the hardware to the graphical front end. System goal is to avoid the main limitations of WNs for SHM particularly in regard to reliability, scalability, and synchronization. We reduce spatial jitter to 125 ns, far below the 120 μs required for high-precision acquisition systems and much better than the 10-μs current solutions, without adding complexity. The system is scalable to a large number of nodes to allow for dense sensor coverage of real-world structures, only limited by a compromise between measurement length and mandatory time to obtain the final result. The system addresses a myriad of problems encountered in a real deployment under difficult conditions, rather than a simulation or laboratory test bed

REDO RSVP: Efficient Signalling for Multimedia in the Internet

Alarming reports of performance and scalability problems associated with per-flow reservations, have led many to lose belief in RSVP and the Integrated Services Architecture that relies on it. Because we are convinced of the need for some form of resource reservation, to support multimedia communications in the Internet, we have set about trying to improve RSVP. By careful study of the protocol, we have identified areas for improvement, and propose REDO RSVP, a reduced overhead version that includes a fast establishment mechanism (FEM). In this paper we describe the rationale for REDO RSVP and present a detailed analysis of its features and operations. We also analyse REDO RSVP by means of simulations, and show that it offers improvements to the performance of RSVP

A New Distributed Approach for Achieving Clock Synchronization in Heterogeneous Networks

Heterogeneous networks have the potential to improve coverage, throughput, and energy efficiency of wireless networks through the use of specialized cellular structures, in particular femtocells and macrocells. However, to reduce interference between different cells, ensure smooth hand-offs from cell to cell, and achieve seamless operation the overall network needs to be synchronized. In this paper a new distributed clock synchronization scheme for heterogeneous networks is proposed that employs the clock drift information available at user-equipments (UEs) to achieve synchronization between non-interacting femtocells and macrocells. Simulation results show that the proposed scheme can significantly reduce the clock drift between macrocells and femtocells and result in timing synchronization throughout the network without introducing significant overhead

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

INE/AUTC 12.0

Structural Damage Detection Robust Against Time Synchronization Errors

Structural Damage Detection based on Wireless Sensor Networks Can Be Affected Significantly by Time Synchronization Errors among Sensors. Precise Time Synchronization of Sensor Nodes Has Been Viewed as Crucial for Addressing This Issue. However, Precise Time Synchronization over a Long Period of Time is Often Impractical in Large Wireless Sensor Networks Due to Two Inherent Challenges. First, Time Synchronization Needs to Be Performed Periodically, Requiring Frequent Wireless Communication among Sensors at Significant Energy Cost. Second, Significant Time Synchronization Errors May Result from Node Failures Which Are Likely to Occur during Long-Term Deployment over Civil Infrastructures. in This Paper, a Damage Detection Approach is Proposed that is Robust Against Time Synchronization Errors in Wireless Sensor Networks. the Paper First Examines the Ways in Which Time Synchronization Errors Distort Identified Mode Shapes, and Then Proposes a Strategy for Reducing Distortion in the Identified Mode Shapes. Modified Values for These Identified Mode Shapes Are Then Used in Conjunction with Flexibility-Based Damage Detection Methods to Localize Damage. This Alternative Approach Relaxes the Need for Frequent Sensor Synchronization and Can Tolerate Significant Time Synchronization Errors Caused by Node Failures. the Proposed Approach is Successfully Demonstrated through Numerical Simulations and Experimental Tests in a Lab. © 2010 IOP Publishing Ltd

Working memory revived in older adults by synchronizing rhythmic brain circuits

Published in final edited form as: Nat Neurosci. 2019 May ; 22(5): 820–827. doi:10.1038/s41593-019-0371-x.Understanding normal brain aging and developing methods to maintain or improve cognition in older adults are major goals of fundamental and translational neuroscience. Here we show a core feature of cognitive decline—working-memory deficits—emerges from disconnected local and long-range circuits instantiated by theta–gamma phase–amplitude coupling in temporal cortex and theta phase synchronization across frontotemporal cortex. We developed a noninvasive stimulation procedure for modulating long-range theta interactions in adults aged 60–76 years. After 25 min of stimulation, frequency-tuned to individual brain network dynamics, we observed a preferential increase in neural synchronization patterns and the return of sender–receiver relationships of information flow within and between frontotemporal regions. The end result was rapid improvement in working-memory performance that outlasted a 50 min post-stimulation period. The results provide insight into the physiological foundations of age-related cognitive impairment and contribute to groundwork for future non-pharmacological interventions targeting aspects of cognitive decline.Accepted manuscrip

Compact Embedded Wireless Sensor-Based Monitoring of Concrete Curing

This work presents the design, construction and testing of a new embedded sensor system for monitoring concrete curing. A specific mote has been implemented to withstand the aggressive environment without affecting the measured variables. The system also includes a real-time monitoring application operating from a remote computer placed in a central location. The testing was done in two phases: the first in the laboratory, to validate the functional requirements of the developed devices; and the second on civil works to evaluate the functional features of the devices, such as range, robustness and flexibility. The devices were successfully implemented resulting in a low cost, highly reliable, compact and non-destructive solution.Fondos FEDER IDI-2010044

A neural probe with up to 966 electrodes and up to 384 configurable channels in 0.13 μm SOI CMOS

In vivo recording of neural action-potential and local-field-potential signals requires the use of high-resolution penetrating probes. Several international initiatives to better understand the brain are driving technology efforts towards maximizing the number of recording sites while minimizing the neural probe dimensions. We designed and fabricated (0.13-μm SOI Al CMOS) a 384-channel configurable neural probe for large-scale in vivo recording of neural signals. Up to 966 selectable active electrodes were integrated along an implantable shank (70 μm wide, 10 mm long, 20 μm thick), achieving a crosstalk of −64.4 dB. The probe base (5 × 9 mm2) implements dual-band recording and a 1

FPGA Operating System for Hard Real Time Applications

In mechatronics, as in many others fields, one of the main aspect is the prototyping. Since the mechatronics covers a lot of complex applications, the availability of a common digital platform to use in all of them is a valid help in the prototyping phase of the project. FPGAs are often used as software acceleration in reconfigurable computers (RC), in which the operating system is a standard off-the-shelf real time operating system such as Linux and VxWorks. The object of the first part of the work is to develop a hardware operating system for mechatronic applications, which means that the FPGA device does not host a soft core processor, able to execute one only operation at a time, but it executes many concurrent hard real time functions allowing the user to develop his own application code taking advantage of the main features of the device: concurrency, flexibility and determinism. The second part of the thesis is related to the project of an electronic module that integrates logic and power devices to drive piezoelectric stack actuators and demonstrate experimentally the results in terms of control of piezoelectric stack tip displacement on atest bench. The electronic module controls up to four piezoelectric stack actuators and guarantees that the correct tip displacement is reached starting from a desired profile. The various opening/closing phases of the actuators are tuned in terms of slew rate, timings and values to reach during all the controlled phase. The control parameters are passed to the control unit by means of a host human machine interface or by an external electronic control unit that acts as a supervisor. This part will illustrate all the passages of the design starting from the constitutive equations of the piezoelectric material up to the final architecture of the control law and implementation passing through: • creation of a FEM model of the piezoelectric stack; • construction of the modal residues model; • FEM model validation; • identification of the electrical equivalent circuit of the piezoelectric stack; • design of the power driver circuit; • design of the control loops; A complete model validation is then performed and experimental results are presente