Crossbow Technology

About: Crossbow Technology is a based out in . It is known for research contribution in the topics: Wireless sensor network & Key distribution in wireless sensor networks. The organization has 22 authors who have published 25 publications receiving 3757 citations.

A wireless sensor network For structural monitoring

Abstract: Structural monitoring---the collection and analysis of structural response to ambient or forced excitation--is an important application of networked embedded sensing with significant commercial potential. The first generation of sensor networks for structural monitoring are likely to be data acquisition systems that collect data at a single node for centralized processing. In this paper, we discuss the design and evaluation of a wireless sensor network system (called Wisden for structural data acquisition. Wisden incorporates two novel mechanisms, reliable data transport using a hybrid of end-to-end and hop-by-hop recovery, and low-overhead data time-stamping that does not require global clock synchronization. We also study the applicability of wavelet-based compression techniques to overcome the bandwidth limitations imposed by low-power wireless radios. We describe our implementation of these mechanisms on the Mica-2 motes and evaluate the performance of our implementation. We also report experiences from deploying Wisden on a large structure.

Health monitoring of civil infrastructures using wireless sensor networks

Abstract: A Wireless Sensor Network (WSN) for Structural Health Monitoring (SHM) is designed, implemented, deployed and tested on the 4200 ft long main span and the south tower of the Golden Gate Bridge (GGB). Ambient structural vibrations are reliably measured at a low cost and without interfering with the operation of the bridge. Requirements that SHM imposes on WSN are identified and new solutions to meet these requirements are proposed and implemented. In the GGB deployment, 64 nodes are distributed over the main span and the tower, collecting ambient vibrations synchronously at 1 kHz rate, with less than 10 mus jitter, and with an accuracy of 30 muG. The sampled data is collected reliably over a 46-hop network, with a bandwidth of 441 B/s at the 46th hop. The collected data agrees with theoretical models and previous studies of the bridge. The deployment is the largest WSN for SHM.

The platforms enabling wireless sensor networks

Abstract: All emphasize low-cost components operating on shoestring power budgets for years at a time in potentially hostile environments without hope of human intervention.

Method and apparatus for determining position and orientation of a moveable object using accelerometers

Abstract: A three-dimensional position and orientation tracking system uses accelerometers to measure acceleration of a moveable object (e.g., a head-mounted display unit or a data glove). A tracking processor generates both position and orientation information on the object relative to a simulation environment as a function of the acceleration data. In one embodiment, a simplified radar-based tracking system is disposed relative to the object and periodically provides additional tracking data on the object to the tracking processor. The tracking processor uses the additional data to correct the position and orientation information using a feedback filter process. The position and orientation information signals generated can be used, for example, in a simulation or virtual reality application. Position and orientation information is received by a simulation processor relative to the object. The simulation processor modifies a simulation environment as a function of the position and orientation information received. Modified simulation environment information (e.g., video and/or audio information) is then presented to a user.

Wireless sensor networks for structural health monitoring

Abstract: Sukun Kim†, Shamim Pakzad‡, David Culler†, James Demmel† Gregory Fenves‡, Steve Glaser‡, Martin Turon? {binetude, culler, demmel}@eecs.berkeley.edu {shamimp, fenves, glaser}@ce.berkeley.edu mturon@xbow.com † Electrical Engineering and Computer Sciences and ‡ Civil and Environmental Engineering ? Crossbow Technology, Inc. University of California at Berkeley 4145 N. First Street Berkeley, CA 94720 San Jose, CA 95134