5,292 research outputs found
A study on acoustic emission signal propagation of a small size multi-cylinder diesel engine
Acoustic emission has been found effective in offering earlier fault detection and improving identification capabilities of faults. However, the sensors are inherently uncalibrated. This paper presents a source to sensor paths calibration technique which can lead to diagnosis of faults in a small size multi-cylinder diesel engine. Preliminary analysis of the acoustic emission (AE) signals is outlined, including time domain, time-frequency domain, and the root mean square (RMS) energy. The results reveal how the RMS energy of a source propagates to the adjacent sensors. The findings lead to allocate the source and estimate its inferences to the adjacent sensor, and finally help to diagnose the small size diesel engines by minimising the crosstalk from multiple cylinders
SCIRIA Openmind seminar series, architecture/pure data/graphical programming
SCIRIA βOpenMindβ was a regular seminar series for University of the Arts London staff, MA and PhD students and the public. The seminars were hosted at Camberwell College of Arts and Chelsea College of Art and Design. The footage, audio and flyers offer an insight into the research processes and activities of SCIRIA members, associates and external speakers
Selective disruption of stimulus-reward learning in glutamate receptor gria 1 knockout mice.
Glutamatergic neurotransmission via AMPA receptors has been an important focus of studies investigating neuronal plasticity. AMPA receptor glutamate receptor 1 (GluR1) subunits play a critical role in long-term potentiation (LTP). Because LTP is thought to be the cellular substrate for learning, we investigated whether mice lacking the GluR1 subunit [gria1 knock-outs (KO)] were capable of learning a simple cue-reward association, and whether such cues were able to influence motivated behavior. Both gria1 KO and wild-type mice learned to associate a light/tone stimulus with food delivery, as evidenced by their approaching the reward after presentation of the cue. During subsequent testing phases, gria1 KO mice also displayed normal approach to the cue in the absence of the reward (Pavlovian approach) and normal enhanced responding for the reward during cue presentations (Pavlovian to instrumental transfer). However, the cue did not act as a reward for learning a new behavior in the KO mice (conditioned reinforcement). This pattern of behavior is similar to that seen with lesions of the basolateral nucleus of the amygdala (BLA), and correspondingly, gria1 KO mice displayed impaired acquisition of responding under a second-order schedule. Thus, mice lacking the GluR1 receptor displayed a specific deficit in conditioned reward, suggesting that GluR1-containing AMPA receptors are important in the synaptic plasticity in the BLA that underlies conditioned reinforcement. Immunostaining for GluR2/3 subunits revealed changes in GluR2/3 expression in the gria1 KOs in the BLA but not the central nucleus of the amygdala (CA), consistent with the behavioral correlates of BLA but not CA function
Review: Acoustic emission technique - Opportunities, challenges and current work at QUT
Acoustic emission (AE) is the phenomenon where high frequency stress waves are generated by rapid release of energy within a material by sources such as crack initiation or growth. AE technique involves recording these stress waves by means of sensors placed on the surface and subsequent analysis of the recorded signals to gather information such as the nature and location of the source. AE is one of the several non-destructive testing (NDT) techniques currently used for structural health monitoring (SHM) of civil, mechanical and aerospace structures. Some of its advantages include ability to provide continuous in-situ monitoring and high sensitivity to crack activity. Despite these advantages, several challenges still exist in successful application of AE monitoring. Accurate localization of AE sources, discrimination between genuine AE sources and spurious noise sources and damage quantification for severity assessment are some of the important issues in AE testing and will be discussed in this paper. Various data analysis and processing approaches will be applied to manage those issues
Fast Computation of Smith Forms of Sparse Matrices Over Local Rings
We present algorithms to compute the Smith Normal Form of matrices over two
families of local rings.
The algorithms use the \emph{black-box} model which is suitable for sparse
and structured matrices. The algorithms depend on a number of tools, such as
matrix rank computation over finite fields, for which the best-known time- and
memory-efficient algorithms are probabilistic.
For an \nxn matrix over the ring \Fzfe, where is a power of an
irreducible polynomial f \in \Fz of degree , our algorithm requires
\bigO(\eta de^2n) operations in \F, where our black-box is assumed to
require \bigO(\eta) operations in \F to compute a matrix-vector product by
a vector over \Fzfe (and is assumed greater than \Pden). The
algorithm only requires additional storage for \bigO(\Pden) elements of \F.
In particular, if \eta=\softO(\Pden), then our algorithm requires only
\softO(n^2d^2e^3) operations in \F, which is an improvement on known dense
methods for small and .
For the ring \ZZ/p^e\ZZ, where is a prime, we give an algorithm which
is time- and memory-efficient when the number of nontrivial invariant factors
is small. We describe a method for dimension reduction while preserving the
invariant factors. The time complexity is essentially linear in where is the number of operations in \ZZ/p\ZZ to evaluate the
black-box (assumed greater than ) and is the total number of non-zero
invariant factors.
To avoid the practical cost of conditioning, we give a Monte Carlo
certificate, which at low cost, provides either a high probability of success
or a proof of failure. The quest for a time- and memory-efficient solution
without restrictions on the number of nontrivial invariant factors remains
open. We offer a conjecture which may contribute toward that end.Comment: Preliminary version to appear at ISSAC 201
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