171 research outputs found
Feasibility Study of Tractor-Test Vehicle Technique for Practical Structural Condition Assessment of Beam-Like Bridge Deck
The tractor-test vehicle technique of non-destructive testing for indirect measurement of the modal properties of a bridge deck is revisited in this paper with several improvements for possible practical application to the structural condition assessment of a beam-like bridge deck. The effect of damping of the vehicle-bridge system is considered and the modal properties from only the first vibration mode of the structure will be used for a quick and simple assessment. The two test vehicles are designed to have the same modal frequency and damping ratio but with parameters in the follower No.2 test vehicle proportional to those in the follower No.1 test vehicle. This effectively removes the effect of road surface roughness in the response of an equivalent vehicle such that the error in the subsequent condition assessment is reduced. Through data collected on-sitetransmitted to theremote computer platform, a simple technique based on the moment-curvature relationship acceptable to practical engineers is adopted for the condition assessment with improvements in the estimation of the element bending stiffness of the deck. Scenarios with different damping, vehicle speed, road surface roughness, and local damages in the bridge structure are studied with or without temperature effect in the measurement. Through numerical simulations and field tests, the tractor-test vehicle technique of non-destructive testing with the proposed modifications and improvements has been demonstrated to give consistently accurate estimates of the element bending stiffness of the bridge deck but with a small error close to the end of the deck
Familial aggregation of migraine and depression: Insights from a large Australian twin sample
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Objectives: This research examined the familial aggregation of migraine, depression, and their co-occurrence.\ud
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Methods: Diagnoses of migraine and depression were determined in a sample of 5,319 Australian twins. Migraine was diagnosed by either self-report, the ID migraineâ„¢ Screener, or International Headache Society (IHS) criteria. Depression was defined by fulfilling either major depressive disorder (MDD) or minor depressive disorder (MiDD) based on the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria. The relative risks (RR) for migraine and depression were estimated in co-twins of twin probands reporting migraine or depression to evaluate their familial aggregation and co-occurrence.\ud
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Results: An increased RR of both migraine and depression in co-twins of probands with the same trait was observed, with significantly higher estimates within monozygotic (MZ) twin pairs compared to dizygotic (DZ) twin pairs. For cross-trait analysis, the RR for migraine in co-twins of probands reporting depression was 1.36 (95% CI: 1.24–1.48) in MZ pairs and 1.04 (95% CI: 0.95–1.14) in DZ pairs; and the RR for depression in co-twins of probands reporting migraine was 1.26 (95% CI: 1.14–1.38) in MZ pairs and 1.02 (95% CI: 0.94–1.11) in DZ pairs. The RR for strict IHS migraine in co-twins of probands reporting MDD was 2.23 (95% CI: 1.81–2.75) in MZ pairs and 1.55 (95% CI: 1.34–1.79) in DZ pairs; and the RR for MDD in co-twins of probands reporting IHS migraine was 1.35 (95% CI: 1.13–1.62) in MZ pairs and 1.06 (95% CI: 0.93–1.22) in DZ pairs.\ud
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Conclusions: We observed significant evidence for a genetic contribution to familial aggregation of migraine and depression. Our findings suggest a bi-directional association between migraine and depression, with an increased risk for depression in relatives of probands reporting migraine, and vice versa. However, the observed risk for migraine in relatives of probands reporting depression was considerably higher than the reverse. These results add further support to previous studies suggesting that patients with comorbid migraine and depression are genetically more similar to patients with only depression than patients with only migraine
Shared genetic factors underlie migraine and depression
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Migraine frequently co-occurs with depression. Using a large sample of Australian twin pairs, we aimed to characterize the extent to which shared genetic factors underlie these two disorders. Migraine was classified using three diagnostic measures, including self-reported migraine, the ID migraine screening tool, or migraine without aura (MO) and migraine with aura (MA) based on International Headache Society (IHS) diagnostic criteria. Major depressive disorder (MDD) and minor depressive disorder (MiDD) were classified using the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria. Univariate and bivariate twin models, with and without sex-limitation, were constructed to estimate the univariate and bivariate variance components and genetic correlation for migraine and depression. The univariate heritability of broad migraine (self-reported, ID migraine, or IHS MO/MA) and broad depression (MiDD or MDD) was estimated at 56% (95% confidence interval [CI]: 53-60%) and 42% (95% CI: 37-46%), respectively. A significant additive genetic correlation (r G = 0.36, 95% CI: 0.29-0.43) and bivariate heritability (h 2 = 5.5%, 95% CI: 3.6-7.8%) was observed between broad migraine and depression using the bivariate Cholesky model. Notably, both the bivariate h 2 (13.3%, 95% CI: 7.0-24.5%) and r G (0.51, 95% CI: 0.37-0.69) estimates significantly increased when analyzing the more narrow clinically accepted diagnoses of IHS MO/MA and MDD. Our results indicate that for both broad and narrow definitions, the observed comorbidity between migraine and depression can be explained almost entirely by shared underlying genetically determined disease mechanisms
S-Rocket: Selective Random Convolution Kernels for Time Series Classification
Random convolution kernel transform (Rocket) is a fast, efficient, and novel
approach for time series feature extraction using a large number of independent
randomly initialized 1-D convolution kernels of different configurations. The
output of the convolution operation on each time series is represented by a
partial positive value (PPV). A concatenation of PPVs from all kernels is the
input feature vector to a Ridge regression classifier. Unlike typical deep
learning models, the kernels are not trained and there is no weighted/trainable
connection between kernels or concatenated features and the classifier. Since
these kernels are generated randomly, a portion of these kernels may not
positively contribute in performance of the model. Hence, selection of the most
important kernels and pruning the redundant and less important ones is
necessary to reduce computational complexity and accelerate inference of Rocket
for applications on the edge devices. Selection of these kernels is a
combinatorial optimization problem. In this paper, we propose a scheme for
selecting these kernels while maintaining the classification performance.
First, the original model is pre-trained at full capacity. Then, a population
of binary candidate state vectors is initialized where each element of a vector
represents the active/inactive status of a kernel. A population-based
optimization algorithm evolves the population in order to find a best state
vector which minimizes the number of active kernels while maximizing the
accuracy of the classifier. This activation function is a linear combination of
the total number of active kernels and the classification accuracy of the
pre-trained classifier with the active kernels. Finally, the selected kernels
in the best state vector are utilized to train the Ridge regression classifier
with the selected kernels
Meta-DMoE: Adapting to Domain Shift by Meta-Distillation from Mixture-of-Experts
In this paper, we tackle the problem of domain shift. Most existing methods
perform training on multiple source domains using a single model, and the same
trained model is used on all unseen target domains. Such solutions are
sub-optimal as each target domain exhibits its own speciality, which is not
adapted. Furthermore, expecting the single-model training to learn extensive
knowledge from the multiple source domains is counterintuitive. The model is
more biased toward learning only domain-invariant features and may result in
negative knowledge transfer. In this work, we propose a novel framework for
unsupervised test-time adaptation, which is formulated as a knowledge
distillation process to address domain shift. Specifically, we incorporate
Mixture-of-Experts (MoE) as teachers, where each expert is separately trained
on different source domains to maximize their speciality. Given a test-time
target domain, a small set of unlabeled data is sampled to query the knowledge
from MoE. As the source domains are correlated to the target domains, a
transformer-based aggregator then combines the domain knowledge by examining
the interconnection among them. The output is treated as a supervision signal
to adapt a student prediction network toward the target domain. We further
employ meta-learning to enforce the aggregator to distill positive knowledge
and the student network to achieve fast adaptation. Extensive experiments
demonstrate that the proposed method outperforms the state-of-the-art and
validates the effectiveness of each proposed component. Our code is available
at https://github.com/n3il666/Meta-DMoE.Comment: Accepted at NeurIPS202
Piezoelectric Material-Polymer Composite Porous Foam for Efficient Dye Degradation via the Piezo-Catalytic Effect
Piezoelectric nanomaterials have been utilized to realize effective charge separation for degrading organic pollutants in water under the action of mechanical vibrations. However, in particulate form, the nanostructured piezoelectric catalysts can flow into the aqueous pollutant and limit its recyclability and reuse. Here, we report a new method of using a barium titanate (BaTiO 3, BTO)-polydimethylsiloxane composite porous foam catalyst to address the challenge of secondary pollution and reusable limits. Piezo-catalytic dye degradation activity of the porous foam can degrade a Rhodamine B (RhB) dye solution by ∼94%, and the composite material exhibits excellent stability after repeated decomposition of 12 cycles. It is suggested that under ultrasonic vibrations, the piezoelectric BTO materials create separated electron-hole pairs that react with hydroxyl ions and oxygen molecules to generate superoxide ( •O 2 -) and hydroxyl ( •OH) radicals for organic dye degradation. The degradation efficiency of RhB is associated with the piezoelectric constant, the specific surface area, and the shape of the material. </p
Few-Shot Class-Incremental Learning via Entropy-Regularized Data-Free Replay
Few-shot class-incremental learning (FSCIL) has been proposed aiming to
enable a deep learning system to incrementally learn new classes with limited
data. Recently, a pioneer claims that the commonly used replay-based method in
class-incremental learning (CIL) is ineffective and thus not preferred for
FSCIL. This has, if truth, a significant influence on the fields of FSCIL. In
this paper, we show through empirical results that adopting the data replay is
surprisingly favorable. However, storing and replaying old data can lead to a
privacy concern. To address this issue, we alternatively propose using
data-free replay that can synthesize data by a generator without accessing real
data. In observing the the effectiveness of uncertain data for knowledge
distillation, we impose entropy regularization in the generator training to
encourage more uncertain examples. Moreover, we propose to relabel the
generated data with one-hot-like labels. This modification allows the network
to learn by solely minimizing the cross-entropy loss, which mitigates the
problem of balancing different objectives in the conventional knowledge
distillation approach. Finally, we show extensive experimental results and
analysis on CIFAR-100, miniImageNet and CUB-200 to demonstrate the
effectiveness of our proposed one.Comment: Accepted by ECCV 202
History's Future in the North End
http://deepblue.lib.umich.edu/bitstream/2027.42/110960/1/history_s_future_in_the_north_endred.pd
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