Search Results for author: Somayeh Sojoudi

Found 50 papers, 8 papers with code

Absence of spurious solutions far from ground truth: A low-rank analysis with high-order losses

no code implementations10 Mar 2024 Ziye Ma, Ying Chen, Javad Lavaei, Somayeh Sojoudi

Matrix sensing problems exhibit pervasive non-convexity, plaguing optimization with a proliferation of suboptimal spurious solutions.

Intent Demonstration in General-Sum Dynamic Games via Iterative Linear-Quadratic Approximations

no code implementations15 Feb 2024 Jingqi Li, Anand Siththaranjan, Somayeh Sojoudi, Claire Tomlin, Andrea Bajcsy

Autonomous agents should be able to coordinate with other agents without knowing their intents ahead of time.

MixedNUTS: Training-Free Accuracy-Robustness Balance via Nonlinearly Mixed Classifiers

1 code implementation3 Feb 2024 Yatong Bai, Mo Zhou, Vishal M. Patel, Somayeh Sojoudi

Adversarial robustness often comes at the cost of degraded accuracy, impeding the real-life application of robust classification models.

Adversarial Robustness Robust classification

Let's Go Shopping (LGS) -- Web-Scale Image-Text Dataset for Visual Concept Understanding

no code implementations9 Jan 2024 Yatong Bai, Utsav Garg, Apaar Shanker, Haoming Zhang, Samyak Parajuli, Erhan Bas, Isidora Filipovic, Amelia N. Chu, Eugenia D Fomitcheva, Elliot Branson, Aerin Kim, Somayeh Sojoudi, Kyunghyun Cho

Vision and vision-language applications of neural networks, such as image classification and captioning, rely on large-scale annotated datasets that require non-trivial data-collecting processes.

Image Captioning Image Classification +3

Mixing Classifiers to Alleviate the Accuracy-Robustness Trade-Off

no code implementations26 Nov 2023 Yatong Bai, Brendon G. Anderson, Somayeh Sojoudi

However, standard learning models often suffer from an accuracy-robustness trade-off, which is a limitation that must be overcome in the control of safety-critical systems that require both high performance and rigorous robustness guarantees.

Tight Certified Robustness via Min-Max Representations of ReLU Neural Networks

no code implementations7 Oct 2023 Brendon G. Anderson, Samuel Pfrommer, Somayeh Sojoudi

The reliable deployment of neural networks in control systems requires rigorous robustness guarantees.

Image Classification

Soft Convex Quantization: Revisiting Vector Quantization with Convex Optimization

no code implementations4 Oct 2023 Tanmay Gautam, Reid Pryzant, ZiYi Yang, Chenguang Zhu, Somayeh Sojoudi

SCQ works like a differentiable convex optimization (DCO) layer: in the forward pass, we solve for the optimal convex combination of codebook vectors that quantize the inputs.

Image Reconstruction Quantization

Projected Randomized Smoothing for Certified Adversarial Robustness

1 code implementation25 Sep 2023 Samuel Pfrommer, Brendon G. Anderson, Somayeh Sojoudi

Randomized smoothing is the current state-of-the-art method for producing provably robust classifiers.

Adversarial Robustness

Scenario-Game ADMM: A Parallelized Scenario-Based Solver for Stochastic Noncooperative Games

no code implementations4 Apr 2023 Jingqi Li, Chih-Yuan Chiu, Lasse Peters, Fernando Palafox, Mustafa Karabag, Javier Alonso-Mora, Somayeh Sojoudi, Claire Tomlin, David Fridovich-Keil

To accommodate this, we decompose the approximated game into a set of smaller games with few constraints for each sampled scenario, and propose a decentralized, consensus-based ADMM algorithm to efficiently compute a generalized Nash equilibrium (GNE) of the approximated game.

Decision Making

Meta-Learning Parameterized First-Order Optimizers using Differentiable Convex Optimization

no code implementations29 Mar 2023 Tanmay Gautam, Samuel Pfrommer, Somayeh Sojoudi

Conventional optimization methods in machine learning and controls rely heavily on first-order update rules.

Meta-Learning

Improving the Accuracy-Robustness Trade-Off of Classifiers via Adaptive Smoothing

1 code implementation29 Jan 2023 Yatong Bai, Brendon G. Anderson, Aerin Kim, Somayeh Sojoudi

While prior research has proposed a plethora of methods that build neural classifiers robust against adversarial robustness, practitioners are still reluctant to adopt them due to their unacceptably severe clean accuracy penalties.

 Ranked #1 on Adversarial Robustness on CIFAR-100 (using extra training data)

Adversarial Robustness

Distributed Optimal Control of Graph Symmetric Systems via Graph Filters

1 code implementation28 Oct 2022 Fengjun Yang, Fernando Gama, Somayeh Sojoudi, Nikolai Matni

Designing distributed optimal controllers subject to communication constraints is a difficult problem unless structural assumptions are imposed on the underlying dynamics and information exchange structure, e. g., sparsity, delay, or spatial invariance.

LQR Control with Sparse Adversarial Disturbances

no code implementations21 Sep 2022 Samuel Pfrommer, Somayeh Sojoudi

Under mild conditions, we show that the disturbance-aware policy converges to the blind online policy if the number of disturbances grows sublinearly in the time horizon.

An Overview and Prospective Outlook on Robust Training and Certification of Machine Learning Models

no code implementations15 Aug 2022 Brendon G. Anderson, Tanmay Gautam, Somayeh Sojoudi

In this discussion paper, we survey recent research surrounding robustness of machine learning models.

Infinite-Horizon Reach-Avoid Zero-Sum Games via Deep Reinforcement Learning

no code implementations18 Mar 2022 Jingqi Li, Donggun Lee, Somayeh Sojoudi, Claire J. Tomlin

We address this problem by designing a new value function with a contracting Bellman backup, where the super-zero level set, i. e., the set of states where the value function is evaluated to be non-negative, recovers the reach-avoid set.

Q-Learning reinforcement-learning +1

Noisy Low-rank Matrix Optimization: Geometry of Local Minima and Convergence Rate

1 code implementation8 Mar 2022 Ziye Ma, Somayeh Sojoudi

We prove that as long as the RIP constant of the noiseless objective is less than $1/3$, any spurious local solution of the noisy optimization problem must be close to the ground truth solution.

Efficient Global Optimization of Two-layer ReLU Networks: Quadratic-time Algorithms and Adversarial Training

no code implementations6 Jan 2022 Yatong Bai, Tanmay Gautam, Somayeh Sojoudi

We apply the robust convex optimization theory to convex training and develop convex formulations that train ANNs robust to adversarial inputs.

Safe Reinforcement Learning with Chance-constrained Model Predictive Control

no code implementations27 Dec 2021 Samuel Pfrommer, Tanmay Gautam, Alec Zhou, Somayeh Sojoudi

Real-world reinforcement learning (RL) problems often demand that agents behave safely by obeying a set of designed constraints.

Model Predictive Control reinforcement-learning +2

Factorization Approach for Low-complexity Matrix Completion Problems: Exponential Number of Spurious Solutions and Failure of Gradient Methods

no code implementations19 Oct 2021 Baturalp Yalcin, Haixiang Zhang, Javad Lavaei, Somayeh Sojoudi

It is well-known that the Burer-Monteiro (B-M) factorization approach can efficiently solve low-rank matrix optimization problems under the RIP condition.

Matrix Completion

Node-Variant Graph Filters in Graph Neural Networks

no code implementations31 May 2021 Fernando Gama, Brendon G. Anderson, Somayeh Sojoudi

We show that, by replacing nonlinear activation functions by NVGFs, frequency creation mechanisms can be designed or learned.

Practical Convex Formulation of Robust One-hidden-layer Neural Network Training

no code implementations25 May 2021 Yatong Bai, Tanmay Gautam, Yu Gai, Somayeh Sojoudi

Recent work has shown that the training of a one-hidden-layer, scalar-output fully-connected ReLU neural network can be reformulated as a finite-dimensional convex program.

Adversarial Robustness Binary Classification

Sharp Restricted Isometry Property Bounds for Low-rank Matrix Recovery Problems with Corrupted Measurements

no code implementations18 May 2021 Ziye Ma, Yingjie Bi, Javad Lavaei, Somayeh Sojoudi

By analyzing the landscape of the non-convex problem, we first propose a global guarantee on the maximum distance between an arbitrary local minimizer and the ground truth under the assumption that the RIP constant is smaller than $1/2$.

Matrix Completion Retrieval

Towards Optimal Branching of Linear and Semidefinite Relaxations for Neural Network Robustness Certification

no code implementations22 Jan 2021 Brendon G. Anderson, Ziye Ma, Jingqi Li, Somayeh Sojoudi

We extend the analysis to the SDP, where the feasible set geometry is exploited to design a branching scheme that minimizes the worst-case SDP relaxation error.

Improving Fairness and Privacy in Selection Problems

no code implementations7 Dec 2020 Mohammad Mahdi Khalili, Xueru Zhang, Mahed Abroshan, Somayeh Sojoudi

In this work, we study the possibility of using a differentially private exponential mechanism as a post-processing step to improve both fairness and privacy of supervised learning models.

Decision Making Fairness

Graph Neural Networks for Distributed Linear-Quadratic Control

no code implementations10 Nov 2020 Fernando Gama, Somayeh Sojoudi

When considering a network system, this renders the optimal controller a centralized one.

Self-Supervised Learning

A Sequential Framework Towards an Exact SDP Verification of Neural Networks

no code implementations16 Oct 2020 Ziye Ma, Somayeh Sojoudi

We analyze the performance of this sequential SDP method both theoretically and empirically, and show that it bridges the gap as the number of cuts increases.

Certifying Neural Network Robustness to Random Input Noise from Samples

no code implementations15 Oct 2020 Brendon G. Anderson, Somayeh Sojoudi

Methods to certify the robustness of neural networks in the presence of input uncertainty are vital in safety-critical settings.

Data-Driven Certification of Neural Networks with Random Input Noise

no code implementations2 Oct 2020 Brendon G. Anderson, Somayeh Sojoudi

Methods to certify the robustness of neural networks in the presence of input uncertainty are vital in safety-critical settings.

Implicit Graph Neural Networks

1 code implementation NeurIPS 2020 Fangda Gu, Heng Chang, Wenwu Zhu, Somayeh Sojoudi, Laurent El Ghaoui

Graph Neural Networks (GNNs) are widely used deep learning models that learn meaningful representations from graph-structured data.

Graph Learning

Tightened Convex Relaxations for Neural Network Robustness Certification

no code implementations1 Apr 2020 Brendon G. Anderson, Ziye Ma, Jingqi Li, Somayeh Sojoudi

In this paper, we consider the problem of certifying the robustness of neural networks to perturbed and adversarial input data.

Decision Making

Spectral Graph Attention Network with Fast Eigen-approximation

no code implementations16 Mar 2020 Heng Chang, Yu Rong, Tingyang Xu, Wenbing Huang, Somayeh Sojoudi, Junzhou Huang, Wenwu Zhu

In this paper, we first introduce the attention mechanism in the spectral domain of graphs and present Spectral Graph Attention Network (SpGAT) that learns representations for different frequency components regarding weighted filters and graph wavelets bases.

Graph Attention Node Classification +1

Power up! Robust Graph Convolutional Network based on Graph Powering

no code implementations25 Sep 2019 Ming Jin, Heng Chang, Wenwu Zhu, Somayeh Sojoudi

By challenging the classical graph Laplacian, we propose a new convolution operator that is provably robust in the spectral domain and is incorporated in the GCN architecture to improve expressivity and interpretability.

Adversarial Robustness

Octave Graph Convolutional Network

no code implementations25 Sep 2019 Heng Chang, Yu Rong, Somayeh Sojoudi, Junzhou Huang, Wenwu Zhu

Many variants of Graph Convolutional Networks (GCNs) for representation learning have been proposed recently and have achieved fruitful results in various domains.

Node Classification Representation Learning

Efficient Learning of Distributed Linear-Quadratic Controllers

no code implementations21 Sep 2019 Salar Fattahi, Nikolai Matni, Somayeh Sojoudi

In this work, we propose a robust approach to design distributed controllers for unknown-but-sparse linear and time-invariant systems.

Global Optimality Guarantees for Nonconvex Unsupervised Video Segmentation

no code implementations9 Jul 2019 Brendon G. Anderson, Somayeh Sojoudi

In this paper, we consider the problem of unsupervised video object segmentation via background subtraction.

Object Segmentation +4

Power up! Robust Graph Convolutional Network via Graph Powering

1 code implementation24 May 2019 Ming Jin, Heng Chang, Wenwu Zhu, Somayeh Sojoudi

By challenging the classical graph Laplacian, we propose a new convolution operator that is provably robust in the spectral domain and is incorporated in the GCN architecture to improve expressivity and interpretability.

Adversarial Robustness

Learning Sparse Dynamical Systems from a Single Sample Trajectory

no code implementations20 Apr 2019 Salar Fattahi, Nikolai Matni, Somayeh Sojoudi

In particular, we show that the proposed estimator can correctly identify the sparsity pattern of the system matrices with high probability, provided that the length of the sample trajectory exceeds a threshold.

Sharp Restricted Isometry Bounds for the Inexistence of Spurious Local Minima in Nonconvex Matrix Recovery

no code implementations7 Jan 2019 Richard Y. Zhang, Somayeh Sojoudi, Javad Lavaei

Using the technique, we prove that in the case of a rank-1 ground truth, an RIP constant of $\delta<1/2$ is both necessary and sufficient for exact recovery from any arbitrary initial point (such as a random point).

Exact Guarantees on the Absence of Spurious Local Minima for Non-negative Rank-1 Robust Principal Component Analysis

no code implementations30 Dec 2018 Salar Fattahi, Somayeh Sojoudi

In particular, it is shown that a constant fraction of the measurements could be grossly corrupted and yet they would not create any spurious local solution.

A Fog Robotic System for Dynamic Visual Servoing

no code implementations16 Sep 2018 Nan Tian, Jinfa Chen, Mas Ma, Robert Zhang, Bill Huang, Ken Goldberg, Somayeh Sojoudi

We use the system to enable robust teleoperation of a dynamic self-balancing robot from the cloud.

Object Recognition

How Much Restricted Isometry is Needed In Nonconvex Matrix Recovery?

no code implementations NeurIPS 2018 Richard Y. Zhang, Cédric Josz, Somayeh Sojoudi, Javad Lavaei

When the linear measurements of an instance of low-rank matrix recovery satisfy a restricted isometry property (RIP)---i. e. they are approximately norm-preserving---the problem is known to contain no spurious local minima, so exact recovery is guaranteed.

Sample Complexity of Sparse System Identification Problem

no code implementations21 Mar 2018 Salar Fattahi, Somayeh Sojoudi

A by-product of this result is that the number of sample trajectories required for sparse system identification is significantly smaller than the dimension of the system.

Large-Scale Sparse Inverse Covariance Estimation via Thresholding and Max-Det Matrix Completion

no code implementations ICML 2018 Richard Y. Zhang, Salar Fattahi, Somayeh Sojoudi

The sparse inverse covariance estimation problem is commonly solved using an $\ell_{1}$-regularized Gaussian maximum likelihood estimator known as "graphical lasso", but its computational cost becomes prohibitive for large data sets.

Matrix Completion

Sparse Inverse Covariance Estimation for Chordal Structures

no code implementations24 Nov 2017 Salar Fattahi, Richard Y. Zhang, Somayeh Sojoudi

We have also derived a closed-form solution that is optimal when the thresholded sample covariance matrix has an acyclic structure.

Matrix Completion

Graphical Lasso and Thresholding: Equivalence and Closed-form Solutions

no code implementations30 Aug 2017 Salar Fattahi, Somayeh Sojoudi

The objective of this paper is to compare the computationally-heavy GL technique with a numerically-cheap heuristic method that is based on simply thresholding the sample covariance matrix.

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