Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultr...

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, many of which occur in the urban environments. The most popular include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems employ different types of sensors to constantly monitor the conditions of the vehicle, and respond in an emergency situation. In this pa...

A key application of sensor networks in smart environments is in monitoring activities of people. We develop several scenarios in which ultrasonic sensors are used for patient and elderly monitoring. In each scenario, we apply different algorithms for data fusion and sensor selection using quality-based or time division approaches. We have devised trajectory-matching algorithms to classify traj...

Manufacturing of carbon fi ber reinforce polymers (CFRPs) presents challenges because of uncertainty in the exact conditions of cure in the material, especially in a complex structure, and this effects the quality of the fi nished product. This work evaluates the use of piezoelectric sensors embedded into CFRP layups before curing to monitor the composite material during the cure cycle. These s...

The nondestructive evaluation (NDE) of adhesively bonded structures is a complex process. Earlier work has confirmed that ultrasonic waves are influenced by the properties of the material in which they travel. Acousto-ultrasonic methods have been widely used by previous researchers to generate ultrasonic waves in plates and bonded structures for flaw detection, visualization, and measurements o...

This article describes a bio-inspired method of identify the type of obstacles which could appear e.g. on the MAV’s (Micro Air Vehicles) way. The method is based on measurements made by a low-cost ultrasonic sensor. This kind of sensors are widely used for a distance measurement. The bio-inspired method used by ultrasound sensors uses echo of ultrasound signal to collect the knowledge about the...

We propose and demonstrate a multiplexing method for ultrasonic sensors based on fiber Bragg gratings (FBGs) that are included inside the laser cavity of a fiber-ring laser. The multiplexing is achieved using add-drop filters to route the light signals, according to their wavelengths, into different optical paths, each of which contains a separate span of erbium-doped fiber (EDF) as the gain me...

Active Fiber Composites (AFC) manufactured at EMPA with commercially available piezoelectric ceramic fibers have been investigated for their potential use as sensors and emitters in various applications. The AFC elements have been evaluated with methods derived from the characterization of ultrasonic transducers and acoustic emission (AE) sensors. Electrical impedance measurements as a function...

A method is presented based on tomographic reconstruction techniques for the visualization of an ultrasonic field. The tall, narrow piezoelectric elements of a one-dimensional receiving array, rotated about its central axis, provide parallel projection input data for tomographic reconstruction of the field. The technique is demonstrated using simulated ultrasonic beams and experimental measurem...

This research demonstrates the feasibility of utilizing nondestructive ultrasonic sensors to monitor the effects of oxygen content, processing time and temperature on the resultant mechanical, structural, and electrical properties of high temperature ceramic superconductors. Ultrasonic velocity changes, as a function of processing time and temperature, have clearly been shown to indicate the tr...