5,167 research outputs found
Instantaneous baseline damage localisation using sensor mapping
In this paper an instantaneously recorded baseline method is proposed using piezoelectric transducers for damage localisation under varying temperature. This method eliminates need for baselines required when operating at different temper- atures by mapping a baseline area onto the interrogation area. Instantaneously recorded baselines and current interrogation signals are calibrated based on the sensor mapping. This allows extraction of damage scatter signal which is used to localise damage. The proposed method is used to localise actual impact damage on a composite plate under varying temperatures. The method is also applied to a stiffened fuselage panel to accurately localise impact damage
I-adic towers in topology
A large variety of cohomology theories is derived from complex cobordism
MU^*(-) by localizing with respect to certain elements or by killing regular
sequences in MU_*. We study the relationship between certain pairs of such
theories which differ by a regular sequence, by constructing topological
analogues of algebraic I-adic towers. These give rise to Higher Bockstein
spectral sequences, which turn out to be Adams spectral sequences in an
appropriate sense. Particular attention is paid to the case of completed
Johnson--Wilson theory E(n)-hat and Morava K-theory K(n) for a given prime p.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-65.abs.htm
Map++: A Crowd-sensing System for Automatic Map Semantics Identification
Digital maps have become a part of our daily life with a number of commercial
and free map services. These services have still a huge potential for
enhancement with rich semantic information to support a large class of mapping
applications. In this paper, we present Map++, a system that leverages standard
cell-phone sensors in a crowdsensing approach to automatically enrich digital
maps with different road semantics like tunnels, bumps, bridges, footbridges,
crosswalks, road capacity, among others. Our analysis shows that cell-phones
sensors with humans in vehicles or walking get affected by the different road
features, which can be mined to extend the features of both free and commercial
mapping services. We present the design and implementation of Map++ and
evaluate it in a large city. Our evaluation shows that we can detect the
different semantics accurately with at most 3% false positive rate and 6% false
negative rate for both vehicle and pedestrian-based features. Moreover, we show
that Map++ has a small energy footprint on the cell-phones, highlighting its
promise as a ubiquitous digital maps enriching service.Comment: Published in the Eleventh Annual IEEE International Conference on
Sensing, Communication, and Networking (IEEE SECON 2014
Estimating Attendance From Cellular Network Data
We present a methodology to estimate the number of attendees to events
happening in the city from cellular network data. In this work we used
anonymized Call Detail Records (CDRs) comprising data on where and when users
access the cellular network. Our approach is based on two key ideas: (1) we
identify the network cells associated to the event location. (2) We verify the
attendance of each user, as a measure of whether (s)he generates CDRs during
the event, but not during other times. We evaluate our approach to estimate the
number of attendees to a number of events ranging from football matches in
stadiums to concerts and festivals in open squares. Comparing our results with
the best groundtruth data available, our estimates provide a median error of
less than 15% of the actual number of attendees
Improvement of mobile trilateration accuracy with modified geo-location techniques.
Masters Degree. University of KwaZulu-Natal, Durban.Abstract available in pdf
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