18 research outputs found
DoPAMINE: Double-sided Masked CNN for Pixel Adaptive Multiplicative Noise Despeckling
We propose DoPAMINE, a new neural network based multiplicative noise
despeckling algorithm. Our algorithm is inspired by Neural AIDE (N-AIDE), which
is a recently proposed neural adaptive image denoiser. While the original
N-AIDE was designed for the additive noise case, we show that the same
framework, i.e., adaptively learning a network for pixel-wise affine denoisers
by minimizing an unbiased estimate of MSE, can be applied to the multiplicative
noise case as well. Moreover, we derive a double-sided masked CNN architecture
which can control the variance of the activation values in each layer and
converge fast to high denoising performance during supervised training. In the
experimental results, we show our DoPAMINE possesses high adaptivity via
fine-tuning the network parameters based on the given noisy image and achieves
significantly better despeckling results compared to SAR-DRN, a
state-of-the-art CNN-based algorithm.Comment: AAAI 2019 Camera Ready Versio
Subtask Gated Networks for Non-Intrusive Load Monitoring
Non-intrusive load monitoring (NILM), also known as energy disaggregation, is
a blind source separation problem where a household's aggregate electricity
consumption is broken down into electricity usages of individual appliances. In
this way, the cost and trouble of installing many measurement devices over
numerous household appliances can be avoided, and only one device needs to be
installed. The problem has been well-known since Hart's seminal paper in 1992,
and recently significant performance improvements have been achieved by
adopting deep networks. In this work, we focus on the idea that appliances have
on/off states, and develop a deep network for further performance improvements.
Specifically, we propose a subtask gated network that combines the main
regression network with an on/off classification subtask network. Unlike
typical multitask learning algorithms where multiple tasks simply share the
network parameters to take advantage of the relevance among tasks, the subtask
gated network multiply the main network's regression output with the subtask's
classification probability. When standby-power is additionally learned, the
proposed solution surpasses the state-of-the-art performance for most of the
benchmark cases. The subtask gated network can be very effective for any
problem that inherently has on/off states
SwiFT: Swin 4D fMRI Transformer
Modeling spatiotemporal brain dynamics from high-dimensional data, such as
functional Magnetic Resonance Imaging (fMRI), is a formidable task in
neuroscience. Existing approaches for fMRI analysis utilize hand-crafted
features, but the process of feature extraction risks losing essential
information in fMRI scans. To address this challenge, we present SwiFT (Swin 4D
fMRI Transformer), a Swin Transformer architecture that can learn brain
dynamics directly from fMRI volumes in a memory and computation-efficient
manner. SwiFT achieves this by implementing a 4D window multi-head
self-attention mechanism and absolute positional embeddings. We evaluate SwiFT
using multiple large-scale resting-state fMRI datasets, including the Human
Connectome Project (HCP), Adolescent Brain Cognitive Development (ABCD), and UK
Biobank (UKB) datasets, to predict sex, age, and cognitive intelligence. Our
experimental outcomes reveal that SwiFT consistently outperforms recent
state-of-the-art models. Furthermore, by leveraging its end-to-end learning
capability, we show that contrastive loss-based self-supervised pre-training of
SwiFT can enhance performance on downstream tasks. Additionally, we employ an
explainable AI method to identify the brain regions associated with sex
classification. To our knowledge, SwiFT is the first Swin Transformer
architecture to process dimensional spatiotemporal brain functional data in an
end-to-end fashion. Our work holds substantial potential in facilitating
scalable learning of functional brain imaging in neuroscience research by
reducing the hurdles associated with applying Transformer models to
high-dimensional fMRI.Comment: NeurIPS 202
Towards More Robust Interpretation via Local Gradient Alignment
Neural network interpretation methods, particularly feature attribution methods, are known to be fragile with respect to adversarial input perturbations.
To address this, several methods for enhancing the local smoothness of the gradient while training have been proposed for attaining robust feature attributions.
However, the lack of considering the normalization of the attributions, which is essential in their visualizations, has been an obstacle to understanding and improving the robustness of feature attribution methods.
In this paper, we provide new insights by taking such normalization into account. First, we show that for every non-negative homogeneous neural network, a naive l2-robust criterion for gradients is not normalization invariant, which means that two functions with the same normalized gradient can have different values.
Second, we formulate a normalization invariant cosine distance-based criterion and derive its upper bound, which gives insight for why simply minimizing the Hessian norm at the input, as has been done in previous work, is not sufficient for attaining robust feature attribution. Finally, we propose to combine both l2 and cosine distance-based criteria as regularization terms to leverage the advantages of both in aligning the local gradient. As a result, we experimentally show that models trained with our method produce much more robust interpretations on CIFAR-10 and ImageNet-100 without significantly hurting the accuracy, compared to the recent baselines. To the best of our knowledge, this is the first work to verify the robustness of interpretation on a larger-scale dataset beyond CIFAR-10, thanks to the computational efficiency of our method
Characterization of Petroleum Heavy Oil Fractions Prepared by Preparatory Liquid Chromatography with Thin-Layer Chromatography, High-Resolution Mass Spectrometry, and Gas Chromatography with an Atomic Emission Detector
In
this study, a preparatory-scale fractionation method was developed.
To verify the effectiveness of this method, an oil sample was fractionated
into five fractions, referred to as saturate, aro1, aro2, polar1,
and polar2; these fractions were completely characterized by thin-layer
chromatography–flame ionization detection (TLC–FID),
field desorption (FD) and (+) atmospheric pressure photoionization
(APPI) high-resolution mass spectrometry (HR-MS), and gas chromatography
with an atomic emission detector (GC–AED). TLC–FID analysis
was used to compare the results obtained by the fractionation method
to those obtained from the conventional saturates, aromatics, resins,
and asphaltenes (SARA) method. FD–MS was employed to characterize
the hydrocarbon class compounds in the saturate and aro1 fractions.
As observed from the FD–MS spectra, non-aromatic hydrocarbon
compounds were abundant in saturates, while mono- and diaromatic compounds
were abundant in the aro1 fraction. This result is in good agreement
with those obtained by HR-MS. (+) APPI HR-MS analysis of fractions
showed that aromaticity increases from saturates to the polar1 fraction
but decreases in the polar2 fraction. Heteroatom class distributions
investigated by (+) APPI HR-MS showed that non-basic nitrogen compounds
were abundant in polar1, while non-aromatic sulfur compounds were
abundant in the polar2 fraction. From the results obtained by the
GC–AED analysis of fractions, nickel porphyrin compounds were
concentrated in the polar1 fraction. Hence, the combined results clearly
demonstrate that the fractionation method is effective for isolating
fractions on a preparative scale
Corrigendum: Affiliation Correction. Development and Validation of a Risk Scoring System Derived from Meta-Analyses for Papillary Thyroid Cancer
Fully Elastic Conductive Films from Viscoelastic Composites
We investigated, for the first time, the conditions where a thermoplastic conductive composite can exhibit completely reversible stretchability at high elongational strains (epsilon = 1.8). We studied a composite of Au nanosheets and a polystyrene-block-polybutadiene-block-polystyrene block copolymer as an example. The composite had an outstandingly low sheet resistance (0.45 Omega/sq). We found that when a thin thermoplastic composite film is placed on a relatively thicker chemically cross-linked elastomer film, it can follow the reversible elastic behavior of the bottom elastomer. Such elasticity comes from the restoration of the block copolymer microstructure. The strong adhesion of the thermoplastic polymer to the metallic fillers is advantageous in the fabrication of mechanically robust, highly conductive, stretchable electrodes. The chemical stability of the Au composite was used to fabricate high luminescence, stretchable electrochemiluminescence displays with a conventional top-bottom electrode setup and with a horizontal electrode setup
X-DNA Origami-Networked Core-Supported Lipid Stratum
DNA hydrogels are promising materials for various fields of research, such as in vitro protein production, drug carrier systems, and cell transplantation. For effective application and further utilization of DNA hydrogels, highly effective methods of nano- and microscale DNA hydrogel fabrication are needed. In this respect, the fundamental advantages of a core-shell structure can provide a simple remedy. An isolated reaction chamber and massive production platform can be provided by a core-shell structure, and lipids are one of the best shell precursor candidates because of their intrinsic biocompatibility and potential for easy modification. Here, we demonstrate a novel core-shell nanostructure made of gene-knitted X-shaped DNA (X-DNA) origami-networked gel core-supported lipid strata. It was simply organized by cross-linking DNA molecules via T4 enzymatic ligation and enclosing them in lipid strata. As a condensed core structure, the DNA gel shows Brownian behavior in a confined area. It has been speculated that they could, in the future, be utilized for in vitro protein synthesis, gene-integration transporters, and even new molecular bottom-up biological machineries. © 2015 American Chemical Society.11Nsciescopu