Wireless sensor networks are the networks consisting of large number of small and tiny sensor nodes. The nodes are supplied with limited power, memory and other resources and perform in-network processing. In this paper, various issues are discussed that actually put the limitations in the well working and the life time of the network. In Wireless sensor network, nodes should consume less power, memory and so data aggregation should be performed. Security is another aspect which should be present in the network. Quality of service, routing, medium access schemes all are considered in designing the protocols.

Wireless Sensor Network -A Survey

This paper studies a number of quantized feedback design problems for linear systems. We consider the case where quantizers are static (memoryless). The common aim of these design problems is to stabilize the given system or to achieve certain performance with the coarsest quantization density. Our main discovery is that the classical sector bound approach is nonconservative for studying these design problems. Consequently, we are able to convert many quantized feedback design problems to well-known robust control problems with sector bound uncertainties. In particular, we derive the coarsest quantization densities for stabilization for multiple-input-multiple-output systems in both state feedback and output feedback cases; and we also derive conditions for quantized feedback control for quadratic cost and H/sub /spl infin// performances.

The sector bound approach to quantized feedback control | NOVA. The University of Newcastle's Digital Repository

Increased awareness of the economic and social effects of aging, deterioration and extreme events on civil infrastructure has been accompanied by recognition of the need for advanced structural health monitoring and damage detection tools. Today, these tasks are done by visual inspection and very traditional methods such as the tap test. This labor-intensive task is done at a frequency of less than once every two years for bridges, and on an as-needed basis for other infrastructures such as buildings. Structural health monitoring techniques based on changes in dynamic characteristics have been studied for the last three decades. When the damage is substantial, these methods have some success in determining if damage has occurred. At incipient stages of damage, however, the existing methods are not as successful. A number of new research projects have been funded to improve the damage detection methods including the use of innovative signal processing, new sensors, and control theory. This survey paper hig...

Review Paper: Health Monitoring of Civil Infrastructure:

‘Smart’ sensors with embedded microprocessors and wireless communication links have the potential to change fundamentally the way civil infrastructure systems are monitored, controlled, and maintained. Indeed, a 2002 National Research Council report noted that the use of networked systems of embedded computers and sensors throughout society could well dwarf all previous milestones in the information revolution. However, a framework does not yet exist that can allow the distributed computing paradigm offered by smart sensors to be employed for structural health monitoring and control systems; current algorithms assume that all data is centrally collected and processed. Such an approach does not scale to systems with densely instrumented arrays of sensors that will be required for the next generation of structural health monitoring and control systems. This paper provides a brief introduction to smart sensing technology and identifies some of the opportunities and associated challenges. Copyright © 2004 John Wiley & Sons, Ltd.

/pdf/smart-sensing-technology-opportunities-and-challenges-1klcubmq3z.pdf

Smart sensing technology: opportunities and challenges

https://www3.ntu.edu.sg/home/ecywen/IEEE/2010_12.pdf

Brief paper: Adaptive actuator failure compensation control of uncertain nonlinear systems with guaranteed transient performance

The Internet technology has provided additional teaching strategies, with online education being one of the most exciting enhancements. A particular challenge for online education in engineering is how to extend the traditional hands-on laboratories to the Internet. Currently, there are two approaches to conducting labs online, virtual and remote labs. Virtual lab is based on software to simulate the lab environment while remote lab, by definition, is an experiment which is conducted and controlled remotely through the Internet. These experiments use real components or instrumentation at a different location from where they are being controlled or conducted. There are many emerging technologies which have been used to develop the virtual and remote laboratory. However, there are few papers that review the virtual and remote laboratory development. In this paper, a review of the different online delivery methods for virtual and remote laboratory development is presented. The open research issues and conclusion with possible future directions on the virtual and remote engineering laboratory development is also presented.

Virtual and Remote Laboratory Development: A Review

As regular inspection for the bolt connection in inaccessible areas is difficult and costly, computer vision technology provides a suitable noncontact approach for real-time bolt looseness detection as an alternative to inspection approaches. However, computer vision still suffers from various impracticalities. In this paper, a new vision-based bolt looseness detection method is designed and implemented with the bolt images acquired by a camera at arbitrary positions around the bolts. The new method includes the perspective transformation of original images acquired, identification of bolt positioning with the convolutional neural network digit recognition, detection of bolt rotation angles using Hough transform line detection, and density-based spatial clustering of applications with noise. To demonstrate the effectiveness of the new method, an experiment with bolted connections is setup. The experimental results demonstrate that the new method can accurately detect the looseness of the bolts in the bolted connection.

Design of a New Vision-Based Method for the Bolts Looseness Detection in Flange Connections

Glass fiber-reinforced polymers (GFRPs) have received increasing attention in recent years due to their overall performance of light weight, low cost and corrosion resistance, and they are increasingly used as reinforcement in concrete structures. However, GFRP material has low elastic modulus and linear elastic properties compared with steel bars, which introduces different bonding characteristics between bars and concrete. Therefore, a reliable monitoring method is urgently needed to detect the bond slip in GFRP-reinforced concrete structures. In this paper, a piezoceramic-based active sensing approach is proposed and developed to find the debonding between a GFRP bar and the concrete structure. In the proposed method, we utilize PZT (lead zirconate titanate) as two transducers. One acts as an actuator which is buried in the concrete structure, and the other acts as a sensor which is attached to the GFRP bar by taking advantage of machinability of the GRRP material. Both transducers are strategically placed to face each other across from the interface between the GFRP bar and the concrete. The actuator provokes a stress wave that travels through the interface. Meanwhile, the PZT patch that is attached to the GFRP bar is used to detect the propagating stress wave. The bonding condition determines how difficult it is for the stress wave traveling through the interface. The occurrence of a bond slip leads to cracks between the bar and the concrete, which dramatically reduces the energy carried by the stress wave through the interface. In this research, two specimens equipped with the PZT transducers are fabricated, and pull-out tests are conducted. To analyze the active sensing data, we use wavelet packet analysis to compute the energy transferred to the sensing PZT patch throughout the process of debonding. Experimental results illustrate that the proposed method can accurately capture the bond slip between the GFRP bar and the concrete.

/pdf/real-time-monitoring-of-bond-slip-between-gfrp-bar-and-2vppx6du7x.pdf

Real-Time Monitoring of Bond Slip between GFRP Bar and Concrete Structure Using Piezoceramic Transducer-Enabled Active Sensing.

Concrete structures with various reinforcements, such as steel bars, composite material tendons, and recently steel plates, are commonly used in civil infrastructures. When an external force overcomes the strength of the bond between the reinforcement and the concrete, bond-slip will occur, resulting in a relative displacement between the reinforcing materials and the concrete. Monitoring bond health plays an important role in guaranteeing structural safety. Recently, researchers have recognized the importance of bond-slip monitoring and performed many related investigations. In this paper, a state-of-the-art review on various smart sensors based on piezoelectric effect and fiber optic technology, as well as corresponding techniques for bond-slip monitoring is presented. Since piezoelectric sensors and fiber-optic sensors are widely used in bond-slip monitoring, their principles and relevant monitoring methods are also introduced in this paper. Particularly, the piezoelectric-based bond-slip monitoring methods including the active sensing method, the electro-mechanical impedance (EMI) method and the passive sensing using acoustic emission (AE) method, and the fiber-optic-based bond-slip detecting approaches including the fiber Bragg grating (FBG) and the distributed fiber optic sensing are highlighted. This paper provides guidance for practical applications and future development of bond-slip monitoring.

https://www.mdpi.com/1424-8220/19/5/1231/pdf

Bond-Slip Monitoring of Concrete Structures Using Smart Sensors-A Review.

The Internet of Things (IoT) is the internetworking of a variety of devices, including sensors. Among all sensors, visual sensors (i.e. cameras) are special because they can provide rich and versatile information. The world already has more than one billion cameras on mobile phones. We define the internet-working of visual sensors as the Internet of Video Things. This article estimates the number of cameras the world will see in 2030 and the implications of a large number of cameras. Transmitting, storing, and analyzing the data from cameras could impose significant challenges to existing technological infrastructures. This paper surveys recent progress in relevant technologies and suggests directions for future research.

Xuemin Chen

Papers

Virtual and Remote Laboratory Development: A Review

Design of a New Vision-Based Method for the Bolts Looseness Detection in Flange Connections

Real-Time Monitoring of Bond Slip between GFRP Bar and Concrete Structure Using Piezoceramic Transducer-Enabled Active Sensing.

Bond-Slip Monitoring of Concrete Structures Using Smart Sensors-A Review.

Internet of video things in 2030: A world with many cameras