27 research outputs found
PaTeCon: A Pattern-Based Temporal Constraint Mining Method for Conflict Detection on Knowledge Graphs
Temporal facts, the facts for characterizing events that hold in specific
time periods, are attracting rising attention in the knowledge graph (KG)
research communities. In terms of quality management, the introduction of time
restrictions brings new challenges to maintaining the temporal consistency of
KGs and detecting potential temporal conflicts. Previous studies rely on
manually enumerated temporal constraints to detect conflicts, which are
labor-intensive and may have granularity issues. We start from the common
pattern of temporal facts and constraints and propose a pattern-based temporal
constraint mining method, PaTeCon. PaTeCon uses automatically determined graph
patterns and their relevant statistical information over the given KG instead
of human experts to generate time constraints. Specifically, PaTeCon
dynamically attaches class restriction to candidate constraints according to
their measuring scores.We evaluate PaTeCon on two large-scale datasets based on
Wikidata and Freebase respectively. The experimental results show that
pattern-based automatic constraint mining is powerful in generating valuable
temporal constraints.Comment: Accepted by AAAI2
Automatic Rule Generation for Time Expression Normalization
The understanding of time expressions includes two sub-tasks: recognition and
normalization. In recent years, significant progress has been made in the
recognition of time expressions while research on normalization has lagged
behind. Existing SOTA normalization methods highly rely on rules or grammars
designed by experts, which limits their performance on emerging corpora, such
as social media texts. In this paper, we model time expression normalization as
a sequence of operations to construct the normalized temporal value, and we
present a novel method called ARTime, which can automatically generate
normalization rules from training data without expert interventions.
Specifically, ARTime automatically captures possible operation sequences from
annotated data and generates normalization rules on time expressions with
common surface forms. The experimental results show that ARTime can
significantly surpass SOTA methods on the Tweets benchmark, and achieves
competitive results with existing expert-engineered rule methods on the
TempEval-3 benchmark.Comment: Accepted to Findings of EMNLP 202
Spike timing reshapes robustness against attacks in spiking neural networks
The success of deep learning in the past decade is partially shrouded in the
shadow of adversarial attacks. In contrast, the brain is far more robust at
complex cognitive tasks. Utilizing the advantage that neurons in the brain
communicate via spikes, spiking neural networks (SNNs) are emerging as a new
type of neural network model, boosting the frontier of theoretical
investigation and empirical application of artificial neural networks and deep
learning. Neuroscience research proposes that the precise timing of neural
spikes plays an important role in the information coding and sensory processing
of the biological brain. However, the role of spike timing in SNNs is less
considered and far from understood. Here we systematically explored the timing
mechanism of spike coding in SNNs, focusing on the robustness of the system
against various types of attacks. We found that SNNs can achieve higher
robustness improvement using the coding principle of precise spike timing in
neural encoding and decoding, facilitated by different learning rules. Our
results suggest that the utility of spike timing coding in SNNs could improve
the robustness against attacks, providing a new approach to reliable coding
principles for developing next-generation brain-inspired deep learning
SpikingJelly: An open-source machine learning infrastructure platform for spike-based intelligence
Spiking neural networks (SNNs) aim to realize brain-inspired intelligence on
neuromorphic chips with high energy efficiency by introducing neural dynamics
and spike properties. As the emerging spiking deep learning paradigm attracts
increasing interest, traditional programming frameworks cannot meet the demands
of the automatic differentiation, parallel computation acceleration, and high
integration of processing neuromorphic datasets and deployment. In this work,
we present the SpikingJelly framework to address the aforementioned dilemma. We
contribute a full-stack toolkit for pre-processing neuromorphic datasets,
building deep SNNs, optimizing their parameters, and deploying SNNs on
neuromorphic chips. Compared to existing methods, the training of deep SNNs can
be accelerated , and the superior extensibility and flexibility of
SpikingJelly enable users to accelerate custom models at low costs through
multilevel inheritance and semiautomatic code generation. SpikingJelly paves
the way for synthesizing truly energy-efficient SNN-based machine intelligence
systems, which will enrich the ecology of neuromorphic computing.Comment: Accepted in Science Advances
(https://www.science.org/doi/10.1126/sciadv.adi1480
A tau fragment links depressive-like behaviors and cognitive declines in Alzheimer’s disease mouse models through attenuating mitochondrial function
IntroductionAlzheimer’s disease (AD) is the most prevalent neurodegenerative disease characterized by extracellular senile plaques including amyloid-β peptides and intracellular neurofibrillary tangles consisting of abnormal Tau. Depression is one of the most common neuropsychiatric symptoms in AD, and clinical evidence demonstrates that depressive symptoms accelerate the cognitive deficit of AD patients. However, the underlying molecular mechanisms of depressive symptoms present in the process of AD remain unclear.MethodsDepressive-like behaviors and cognitive decline in hTau mice were induced by chronic restraint stress (CRS). Computational prediction and molecular experiments supported that an asparagine endopeptidase (AEP)-derived Tau fragment, Tau N368 interacts with peroxisome proliferator-activated receptor delta (PPAR-δ). Further behavioral studies investigated the role of Tau N368-PPAR-δ interaction in depressive-like behaviors and cognitive declines of AD models exposed to CRS.ResultsWe found that mitochondrial dysfunction was positively associated with depressive-like behaviors and cognitive deficits in hTau mice. Chronic stress increased Tau N368 and promoted the interaction of Tau N368 with PPAR-δ, repressing PPAR-δ–mediated transactivation in the hippocampus of mice. Then we predicted and identified the binding sites of PPAR-δ. Finally, inhibition of AEP, clearance of Tau N368 and pharmacological activation of PPAR-δ effectively alleviated CRS-induced depressive-like behaviors and cognitive decline in mice.ConclusionThese results demonstrate that Tau N368 in the hippocampus impairs mitochondrial function by suppressing PPAR-δ, facilitating the occurrence of depressive-like behaviors and cognitive decline. Therefore, our findings may provide new mechanistic insight in the pathophysiology of depression-like phenotype in mouse models of Alzheimer’s disease
PaTeCon: A Pattern-Based Temporal Constraint Mining Method for Conflict Detection on Knowledge Graphs
Temporal facts, the facts for characterizing events that hold in specific time periods, are attracting rising attention in the knowledge graph (KG) research communities. In terms of quality management, the introduction of time restrictions brings new challenges to maintaining the temporal consistency of KGs and detecting potential temporal conflicts. Previous studies rely on manually enumerated temporal constraints to detect conflicts, which are labor-intensive and may have granularity issues. We start from the common pattern of temporal facts and constraints and propose a pattern-based temporal constraint mining method, PaTeCon. PaTeCon uses automatically determined graph patterns and their relevant statistical information over the given KG instead of human experts to generate time constraints. Specifically, PaTeCon dynamically attaches type restriction to candidate constraints according to their measuring scores. We evaluate PaTeCon on two large-scale datasets based on Wikidata and Freebase respectively, the experimental results show that pattern-based automatic constraint mining is powerful in generating valuable temporal constraints
Reducing ANN-SNN Conversion Error through Residual Membrane Potential
Spiking Neural Networks (SNNs) have received extensive academic attention due to the unique properties of low power consumption and high-speed computing on neuromorphic chips. Among various training methods of SNNs, ANN-SNN conversion has shown the equivalent level of performance as ANNs on large-scale datasets. However, unevenness error, which refers to the deviation caused by different temporal sequences of spike arrival on activation layers, has not been effectively resolved and seriously suffers the performance of SNNs under the condition of short time-steps. In this paper, we make a detailed analysis of unevenness error and divide it into four categories. We point out that the case of the ANN output being zero while the SNN output being larger than zero accounts for the largest percentage. Based on this, we theoretically prove the sufficient and necessary conditions of this case and propose an optimization strategy based on residual membrane potential to reduce unevenness error. The experimental results show that the proposed method achieves state-of-the-art performance on CIFAR-10, CIFAR-100, and ImageNet datasets. For example, we reach top-1 accuracy of 64.32% on ImageNet with 10-steps. To the best of our knowledge, this is the first time ANN-SNN conversion can simultaneously achieve high accuracy and ultra-low-latency on the complex dataset. Code is available at https://github.com/hzc1208/ANN2SNN_SRP