Publications

Reinforcement Learning-Based Adaptive Feature Boosting for Smart Grid Intrusion Detection
Chengming Hu
Jun Yan
Xue (Steve) Liu
Intrusion detection systems (IDSs) are crucial in the security monitoring for the smart grid with increasing machine-to-machine communicatio… (see more)ns and cyber threats thereafter. However, the multi-sourced, correlated, and heterogeneous smart grid data pose significant challenges to the accurate attack detection by IDSs. To improve the attack detection, this paper proposes Reinforcement Learning-based Adaptive Feature Boosting, which aims to leverage a series of AutoEncoders (AEs) to capture critical features from the multi-sourced smart grid data for the classification of normal, fault, and attack events. Multiple AEs are utilized to extract representative features from different feature sets that are automatically generated through a weighted feature sampling process; each AE-extracted feature set is then applied to build a Random Forest (RF) base classifier. In the feature sampling process, Deep Deterministic Policy Gradient (DDPG) is introduced to dynamically determine the feature sampling probability based on the classification accuracy. The critical features that improve the classification accuracy are assigned larger sampling probabilities and increasingly participate in the training of next AE. The presence of critical features is increased in the event classification over the multi-sourced smart grid data. Considering potential different alarms among base classifiers, an ensemble classifier is further built to distinguish normal, fault, and attack events. Our proposed approach is evaluated on the two realistic datasets collected from Hardware-In-the-Loop (HIL) and WUSTIL-IIOT-2021 security testbeds, respectively. The evaluation on the HIL security dataset shows that our proposed approach achieves the classification accuracy with 97.28%, an effective 5.5% increase over the vanilla Adaptive Feature Boosting. Moreover, the proposed approach not only accurately and stably selects critical features on the WUSTIL-IIOT-2021 dataset based on the significant difference of feature sampling probabilities between critical and uncritical features, i.e., the probabilities greater than 0.08 and less than 0.01, but also outperforms the other best-performing approaches with the increasing Matthew Correlation Coefficient (MCC) of 8.03%.
2023-07-01
IEEE Transactions on Smart Grid (published)
doi.org
SkillQG: Learning to Generate Question for Reading Comprehension Assessment
Xiaoqiang Wang
Bang Liu
Siliang Tang
Lingfei Wu
2023-07-01
Findings of the Association for Computational Linguistics: ACL 2023 (published)
doi.org
arxiv.org
Spatial Hard Attention Modeling via Deep Reinforcement Learning for Skeleton-Based Human Activity Recognition
Bahareh Nikpour
Narges Armanfard
Deep learning-based algorithms have been very successful in skeleton-based human activity recognition. Skeleton data contains 2-D or 3-D coo… (see more)rdinates of human body joints. The main focus of most of the existing skeleton-based activity recognition methods is on designing new deep architectures to learn discriminative features, where all body joints are considered equally important in recognition. However, the importance of joints varies as an activity proceeds within a video and across different activities. In this work, we hypothesize that selecting relevant joints, prior to recognition, can enhance performance of the existing deep learning-based recognition models. We propose a spatial hard attention finding method that aims to remove the uninformative and/or misleading joints at each frame. We formulate the joint selection problem as a Markov decision process and employ deep reinforcement learning to train the proposed spatial-attention-aware agent. No extra labels are needed for the agent’s training. The agent takes a sequence of features extracted from skeleton video as input and outputs a sequence of probabilities for joints. The proposed method can be considered as a general framework that can be integrated with the existing skeleton-based activity recognition methods for performance improvement purposes. We obtain very competitive activity recognition results on three commonly used human activity recognition datasets.
2023-07-01
IEEE Transactions on Systems, Man, and Cybernetics: Systems (published)
doi.org
Studying the challenges of developing hardware description language programs
Fatemeh Yousefifeshki
Heng Li
Foutse Khomh
2023-07-01
Information and Software Technology (published)
doi.org
EuclidNets: An Alternative Operation for Efficient Inference of Deep Learning Models
Xinlin Li
Mariana Parazeres
Adam M. Oberman
Alireza Ghaffari
Masoud Asgharian
Vahid Nia
2023-06-30
SN Computer Science (published)
doi.org
arxiv.org
Generalization Limits of Graph Neural Networks in Identity Effects Learning
Giuseppe Alessio D'inverno
Simone Brugiapaglia
Mirco Ravanelli
Graph Neural Networks (GNNs) have emerged as a powerful tool for data-driven learning on various graph domains. They are usually based on a … (see more)message-passing mechanism and have gained increasing popularity for their intuitive formulation, which is closely linked to the Weisfeiler-Lehman (WL) test for graph isomorphism to which they have been proven equivalent in terms of expressive power. In this work, we establish new generalization properties and fundamental limits of GNNs in the context of learning so-called identity effects, i.e., the task of determining whether an object is composed of two identical components or not. Our study is motivated by the need to understand the capabilities of GNNs when performing simple cognitive tasks, with potential applications in computational linguistics and chemistry. We analyze two case studies: (i) two-letters words, for which we show that GNNs trained via stochastic gradient descent are unable to generalize to unseen letters when utilizing orthogonal encodings like one-hot representations; (ii) dicyclic graphs, i.e., graphs composed of two cycles, for which we present positive existence results leveraging the connection between GNNs and the WL test. Our theoretical analysis is supported by an extensive numerical study.
2023-06-30
ArXiv (preprint)
doi.org
arxiv.org
Reference panel-guided super-resolution inference of Hi-C data
Yanlin Zhang
Mathieu Blanchette
Abstract Motivation Accurately assessing contacts between DNA fragments inside the nucleus with Hi-C experiment is crucial for understanding… (see more) the role of 3D genome organization in gene regulation. This challenging task is due in part to the high sequencing depth of Hi-C libraries required to support high-resolution analyses. Most existing Hi-C data are collected with limited sequencing coverage, leading to poor chromatin interaction frequency estimation. Current computational approaches to enhance Hi-C signals focus on the analysis of individual Hi-C datasets of interest, without taking advantage of the facts that (i) several hundred Hi-C contact maps are publicly available and (ii) the vast majority of local spatial organizations are conserved across multiple cell types. Results Here, we present RefHiC-SR, an attention-based deep learning framework that uses a reference panel of Hi-C datasets to facilitate the enhancement of Hi-C data resolution of a given study sample. We compare RefHiC-SR against tools that do not use reference samples and find that RefHiC-SR outperforms other programs across different cell types, and sequencing depths. It also enables high-accuracy mapping of structures such as loops and topologically associating domains. Availability and implementation https://github.com/BlanchetteLab/RefHiC.
2023-06-30
Bioinformatics (published)
doi.org
Should We Feed the Trolls? Using Marketer-Generated Content to Explain Average Toxicity and Product Usage
Marcelo Vinhal Nepomuceno
Hooman Rahemi
Tolga Cenesizoglu
Laurent Charlin
2023-06-29
Journal of Interactive Marketing (published)
doi.org
Cortico-Cerebellar neurodynamics during social interaction in Autism Spectrum Disorders
Fleur Gaudfernau
Aline Lefebvre
Denis-Alexander Engemann
Amandine Pedoux
Anna Bánki
Florence Baillin
Benjamin Landman
Frederique Amsellem
Anna Maruani
Thomas Bourgeron
Richard Delorme
Guillaume Dumas
2023-06-28
NeuroImage : Clinical (published)
doi.org
On the Identifiability of Quantized Factors
Vitória Barin Pacela
Kartik Ahuja
Simon Lacoste-Julien
Pascal Vincent
Disentanglement aims to recover meaningful latent ground-truth factors from the observed distribution solely, and is formalized through the … (see more)theory of identifiability. The identifiability of independent latent factors is proven to be impossible in the unsupervised i.i.d. setting under a general nonlinear map from factors to observations. In this work, however, we demonstrate that it is possible to recover quantized latent factors under a generic nonlinear diffeomorphism. We only assume that the latent factors have independent discontinuities in their density, without requiring the factors to be statistically independent. We introduce this novel form of identifiability, termed quantized factor identifiability, and provide a comprehensive proof of the recovery of the quantized factors.
2023-06-28
ArXiv (preprint)
arxiv.org
arxiv.org
Pixelated Reconstruction of Foreground Density and Background Surface Brightness in Gravitational Lensing Systems Using Recurrent Inference Machines
Alexandre Adam
Laurence Perreault-Levasseur
Yashar Hezaveh
Max Welling
Modeling strong gravitational lenses in order to quantify distortions in the images of background sources and to reconstruct the mass densit… (see more)y in foreground lenses has been a difficult computational challenge. As the quality of gravitational lens images increases, the task of fully exploiting the information they contain becomes computationally and algorithmically more difficult. In this work, we use a neural network based on the recurrent inference machine to reconstruct simultaneously an undistorted image of the background source and the lens mass density distribution as pixelated maps. The method iteratively reconstructs the model parameters (the image of the source and a pixelated density map) by learning the process of optimizing the likelihood given the data using the physical model (a ray-tracing simulation), regularized by a prior implicitly learned by the neural network through its training data. When compared to more traditional parametric models, the proposed method is significantly more expressive and can reconstruct complex mass distributions, which we demonstrate by using realistic lensing galaxies taken from the IllustrisTNG cosmological hydrodynamic simulation.
2023-06-27
The Astrophysical Journal (published)
doi.org
arxiv.org
Adaptive Discrete Communication Bottlenecks with Dynamic Vector Quantization
Dianbo Liu
Alex Lamb
Xu Ji
Pascal Notsawo
Michael Curtis Mozer
Yoshua Bengio
Kenji Kawaguchi
2023-06-26
Proceedings of the AAAI Conference on Artificial Intelligence (published)
doi.org
arxiv.org