889 research outputs found
Optimisation- based time slot assignment and synchronisation for TDMA MAC in industrial wireless sensor network
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/166209/1/cmu2bf02232.pd
Kinematic strategies for obstacle-crossing in older adults with mild cognitive impairment
IntroductionMild cognitive impairment (MCI) is considered a transitional stage between soundness of mind and dementia, often involving problems with memory, which may lead to abnormal postural control and altered end-point control when dealing with neuromechanical challenges during obstacle-crossing. The study aimed to identify the end-point control and angular kinematics of the pelvis-leg apparatus while crossing obstacles for both leading and trailing limbs.Methods12 patients with MCI (age: 66.7 ± 4.2 y/o; height: 161.3 ± 7.3 cm; mass: 62.0 ± 13.6 kg) and 12 healthy adults (age: 67.7 ± 2.9 y/o; height: 159.3 ± 6.1 cm; mass: 61.2 ± 12.0 kg) each walked and crossed obstacles of three different heights (10, 20, and 30% of leg length). Angular motions of the pelvis and lower limbs and toe-obstacle clearances during leading- and trailing-limb crossings were calculated. Two-way analyses of variance were used to study between-subject (group) and within-subject (obstacle height) effects on the variables. Whenever a height effect was found, a polynomial test was used to determine the trend. A significance level of α = 0.05 was set for all tests.ResultsPatients with MCI significantly increased pelvic anterior tilt, hip abduction, and knee adduction in the swing limb during leading-limb crossing when compared to controls (p < 0.05). During trailing-limb crossing, the MCI group showed significantly decreased pelvic posterior tilt, as well as ankle dorsiflexion in the trailing swing limb (p < 0.05).ConclusionPatients with MCI adopt altered kinematic strategies for successful obstacle-crossing. The patients were able to maintain normal leading and trailing toe-obstacle clearances for all tested obstacle heights with a specific kinematic strategy, namely increased pelvic anterior tilt, swing hip abduction, and knee adduction during leading-limb crossing, and decreased pelvic posterior tilt and swing ankle dorsiflexion during trailing-limb crossing. The current results suggest that regular monitoring of obstacle-crossing kinematics for reduced toe-obstacle clearance or any signs of changes in crossing strategy may be helpful for early detection of compromised obstacle-crossing ability in patients with single-domain amnestic MCI. Further studies using a motor/cognitive dual-task approach on the kinematic strategies adopted by multiple-domain MCI will be needed for a complete picture of the functional adaptations in such a patient group
Towards General-Purpose Text-Instruction-Guided Voice Conversion
This paper introduces a novel voice conversion (VC) model, guided by text
instructions such as "articulate slowly with a deep tone" or "speak in a
cheerful boyish voice". Unlike traditional methods that rely on reference
utterances to determine the attributes of the converted speech, our model adds
versatility and specificity to voice conversion. The proposed VC model is a
neural codec language model which processes a sequence of discrete codes,
resulting in the code sequence of converted speech. It utilizes text
instructions as style prompts to modify the prosody and emotional information
of the given speech. In contrast to previous approaches, which often rely on
employing separate encoders like prosody and content encoders to handle
different aspects of the source speech, our model handles various information
of speech in an end-to-end manner. Experiments have demonstrated the impressive
capabilities of our model in comprehending instructions and delivering
reasonable results.Comment: Accepted to ASRU 202
Transformer-based Learned Image Compression for Joint Decoding and Denoising
This work introduces a Transformer-based image compression system. It has the
flexibility to switch between the standard image reconstruction and the
denoising reconstruction from a single compressed bitstream. Instead of
training separate decoders for these tasks, we incorporate two add-on modules
to adapt a pre-trained image decoder from performing the standard image
reconstruction to joint decoding and denoising. Our scheme adopts a two-pronged
approach. It features a latent refinement module to refine the latent
representation of a noisy input image for reconstructing a noise-free image.
Additionally, it incorporates an instance-specific prompt generator that adapts
the decoding process to improve on the latent refinement. Experimental results
show that our method achieves a similar level of denoising quality to training
a separate decoder for joint decoding and denoising at the expense of only a
modest increase in the decoder's model size and computational complexity.Comment: Accepted to PCS 202
Strong and broadly tunable plasmon resonances in thick films of aligned carbon nanotubes
Low-dimensional plasmonic materials can function as high quality terahertz
and infrared antennas at deep subwavelength scales. Despite these antennas'
strong coupling to electromagnetic fields, there is a pressing need to further
strengthen their absorption. We address this problem by fabricating thick films
of aligned, uniformly sized carbon nanotubes and showing that their plasmon
resonances are strong, narrow, and broadly tunable. With thicknesses ranging
from 25 to 250 nm, our films exhibit peak attenuation reaching 70%, quality
factors reaching 9, and electrostatically tunable peak frequencies by a factor
of 2.3x. Excellent nanotube alignment leads to the attenuation being 99%
linearly polarized along the nanotube axis. Increasing the film thickness
blueshifts the plasmon resonators down to peak wavelengths as low as 1.4
micrometers, promoting them to a new near-infrared regime in which they can
both overlap the S11 nanotube exciton energy and access the technologically
important infrared telecom band.Comment: 19 pages, 5 figures, main text followed by supporting informatio
A Giant Protocluster of Galaxies at Redshift 5.7
Galaxy clusters trace the largest structures of the Universe and provide
ideal laboratories for studying galaxy evolution and cosmology. Clusters with
extended X-ray emission have been discovered at redshifts up to z ~ 2.5.
Meanwhile, there has been growing interest in hunting for protoclusters, the
progenitors of clusters, at higher redshifts. It is, however, very challenging
to find the largest protoclusters at early times when they start to assemble.
Here we report a giant protocluster of galaxies at redshift z = 5.7, when the
Universe was only one billion years old. This protocluster occupies a volume of
about 35x35x35 cubic co-moving megaparsecs. It is embedded in an even larger
overdense region with at least 41 spectroscopically confirmed, luminous
Lyman-alpha emitting galaxies (Lyman-alpha Emitters, or LAEs), including
several previously reported LAEs. Its LAE density is 6.6 times the average
density at z ~ 5.7. It is the only one of its kind in an LAE survey in four
square degrees on the sky. Such a large structure is also rarely seen in
current cosmological simulations. This protocluster will collapse into a galaxy
cluster with a mass of (3.6+/-0.9) x 10^{15} solar masses, comparable to those
of the most massive clusters or protoclusters known to date.Comment: Published in Nature Astronomy on Oct 15, 2018 (DOI:
10.1038/s41550-018-0587-9
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