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Hierarchical video summarisation in reference frame subspace
In this paper, a hierarchical video structure summarization approach using Laplacian Eigenmap is proposed, where a small set of reference frames is selected from the video sequence to form a reference subspace to measure the dissimilarity between two arbitrary frames. In the proposed summarization scheme, the shot-level key frames are first detected from the continuity of inter-frame dissimilarity, and the sub-shot level and scene level representative frames are then summarized by using k-mean clustering. The experiment is carried on both test videos and movies, and the results show that in comparison with a similar approach using latent semantic analysis, the proposed approach using Laplacian Eigenmap can achieve a better recall rate in keyframe detection, and gives an efficient hierarchical summarization at sub shot, shot and scene levels subsequently
Producing a commentary slows concurrent hazard perception responses
Commentary driver training involves teaching drivers how to verbally acknowledge their perceptual and cognitive processes while driving, and has been shown to improve performance in driving-related tasks. However, those studies demonstrating benefits of commentary training have not done so under conditions of live commentary, which is the typical protocol used with advanced drivers. In the current study we present the results of two experiments that show that producing a commentary can actually slow responses to hazards on a concurrent hazard perception task. In Experiment 1 participants producing a live commentary showed significantly longer hazard response times than an untrained, silent, control group. In Experiment 2 a shorter, clipped commentary was introduced to attempt to reduce the demands placed upon participants. However, both the clipped and full commentary conditions showed reduced accuracy and longer response times, relative to a silent condition, and no difference was observed between the two types of commentary. Analysis of eye movements in both experiments revealed that fixation durations were shorter when a commentary was produced, but time to first fixate the hazard was not affected. This suggests that commentaries encourage more active interrogation of the visual scene, but that this can be detrimental to performance in average drivers
Spectral Action for Robertson-Walker metrics
We use the Euler-Maclaurin formula and the Feynman-Kac formula to extend our
previous method of computation of the spectral action based on the Poisson
summation formula. We show how to compute directly the spectral action for the
general case of Robertson-Walker metrics. We check the terms of the expansion
up to a_6 against the known universal formulas of Gilkey and compute the
expansion up to a_{10} using our direct method
Knee moments of anterior cruciate ligament reconstructed and control participants during normal and inclined walking
Objectives: Prior injury to the knee, particularly
anterior cruciate ligament (ACL) injury, is known to
predispose one to premature osteoarthritis (OA). The
study sought to explore if there was a biomechanical
rationale for this process by investigating changes in
external knee moments between people with a
history of ACL injury and uninjured participants
during walking: (1) on different surface inclines and
(2) at different speeds. In addition we assessed
functional differences between the groups.
Participants: 12 participants who had undergone
ACL reconstruction (ACLR) and 12 volunteers with
no history of knee trauma or injury were recruited
into this study. Peak knee flexion and adduction
moments were assessed during flat (normal and
slow speed), uphill and downhill walking using an
inclined walkway with an embedded Kistler Force
plate, and a ten-camera Vicon motion capture
system. Knee injury and Osteoarthritis Outcome
Score (KOOS) was used to assess function.
Multivariate analysis of variance (MANOVA) was
used to examine statistical differences in gait and
KOOS outcomes.
Results: No significant difference was observed in
the peak knee adduction moment between ACLR and
control participants, however, in further analysis,
MANOVA revealed that ACLR participants with an
additional meniscal tear or collateral ligament
damage (7 participants) had a significantly higher
adduction moment (0.33±0.12 Nm/kg m) when
compared with those with isolated ACLR
(5 participants, 0.1±0.057 Nm/kg m) during gait at
their normal speed ( p<0.05). A similar (nonsignificant)
trend was seen during slow, uphill and
downhill gait.
Conclusions: Participants with an isolated ACLR
had a reduced adductor moment rather an increased
moment, thus questioning prior theories on OA
development. In contrast, those participants who
had sustained associated trauma to other key knee
structures were observed to have an increased
adduction moment. Additional injury concurrent
with an ACL rupture may lead to a higher
predisposition to osteoarthritis than isolated ACL
deficiency alone
Massive Hermitian Gravity
Einstein-Strauss Hermitian gravity was recently formulated as a gauge theory
where the tangent group is taken to be the pseudo-unitary group instead of the
orthogonal group. A Higgs mechanism for massive gravity was also formulated. We
generalize this construction to obtain massive Hermitian gravity with the use
of a complex Higgs multiplet. We show that both the graviton and antisymmetric
tensor acquire the same mass. At the linearized level, the theory is ghost free
around Minkowski background and describes a massive graviton with five degrees
of freedom and an antisymmetric field with three degrees of of freedom. We
determine the strong coupling scales for these degrees of freedom and argue
that the potential nonlinear ghosts, if they exist, have to decouple from the
gravitational degrees of freedom in strong coupling regime.Comment: 10 page
Ultrasoft NLL Running of the Nonrelativistic O(v) QCD Quark Potential
Using the nonrelativistic effective field theory vNRQCD, we determine the
contribution to the next-to-leading logarithmic (NLL) running of the effective
quark-antiquark potential at order v (1/mk) from diagrams with one potential
and two ultrasoft loops, v being the velocity of the quarks in the c.m. frame.
The results are numerically important and complete the description of ultrasoft
next-to-next-to-leading logarithmic (NNLL) order effects in heavy quark pair
production and annihilation close to threshold.Comment: 25 pages, 7 figures, 3 tables; minor modifications, typos corrected,
references added, footnote adde
Automated design of robust discriminant analysis classifier for foot pressure lesions using kinematic data
In the recent years, the use of motion tracking systems for acquisition of functional biomechanical gait data, has received increasing interest due to the richness and accuracy of the measured kinematic information. However, costs frequently restrict the number of subjects employed, and this makes the dimensionality of the collected data far higher than the available samples. This paper applies discriminant analysis algorithms to the classification of patients with different types of foot lesions, in order to establish an association between foot motion and lesion formation. With primary attention to small sample size situations, we compare different types of Bayesian classifiers and evaluate their performance with various dimensionality reduction techniques for feature extraction, as well as search methods for selection of raw kinematic variables. Finally, we propose a novel integrated method which fine-tunes the classifier parameters and selects the most relevant kinematic variables simultaneously. Performance comparisons are using robust resampling techniques such as Bootstrapand k-fold cross-validation. Results from experimentations with lesion subjects suffering from pathological plantar hyperkeratosis, show that the proposed method can lead tocorrect classification rates with less than 10% of the original features
Modeling pedestrian evacuation movement in a swaying ship
With the advance in living standard, cruise travel has been rapidly expanding
around the world in recent years. The transportation of passengers in water has
also made a rapid development. It is expected that ships will be more and more
widely used. Unfortunately, ship disasters occurred in these years caused
serious losses. It raised the concern on effectiveness of passenger evacuation
on ships. The present study thus focuses on pedestrian evacuation features on
ships. On ships, passenger movements are affected by the periodical water
motion and thus are quite different from the characteristic when walking on
static horizontal floor. Taking into consideration of this special feature, an
agent-based pedestrian model is formulized and the effect of ship swaying on
pedestrian evacuation efficiency is investigated. Results indicated that the
proposed model can be used to quantify the special evacuation process on ships.Comment: Traffic and Granular Flow'15, At Delft, the Netherland
Entanglement entropy of the composite fermion non-Fermi liquid state
The so-called ``non-Fermi liquid'' behavior is very common in strongly
correlated systems. However, its operational definition in terms of ``what it
is not'' is a major obstacle against theoretical understanding of this
fascinating correlated state. Recently there has been much interest in
entanglement entropy as a theoretical tool to study non-Fermi liquids. So far
explicit calculations have been limited to models without direct experimental
realizations. Here we focus on a two dimensional electron fluid under magnetic
field and filling fraction , which is believed to be a non-Fermi
liquid state. Using the composite fermion (CF) wave-function which captures the
state very accurately, we compute the second R\'enyi entropy using
variational Monte-Carlo technique and an efficient parallel algorithm. We find
the entanglement entropy scales as with the length of the boundary
as it does for free fermions, albeit with a pre-factor twice that of the
free fermion. We contrast the results against theoretical conjectures and
discuss the implications of the results.Comment: 4+ page
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