Search Results for author: Ali Tajer

Found 19 papers, 5 papers with code

Causal Bandits with General Causal Models and Interventions

no code implementations1 Mar 2024 Zirui Yan, Dennis Wei, Dmitriy Katz-Rogozhnikov, Prasanna Sattigeri, Ali Tajer

First, the structural causal models (SCMs) are assumed to be unknown and drawn arbitrarily from a general class $\mathcal{F}$ of Lipschitz-continuous functions.

Blackout Mitigation via Physics-guided RL

no code implementations17 Jan 2024 Anmol Dwivedi, Santiago Paternain, Ali Tajer

This paper considers the sequential design of remedial control actions in response to system anomalies for the ultimate objective of preventing blackouts.

Reinforcement Learning (RL)

Robust Causal Bandits for Linear Models

no code implementations30 Oct 2023 Zirui Yan, Arpan Mukherjee, Burak Varici, Ali Tajer

Cumulative regret is adopted as the design criteria, based on which the objective is to design a sequence of interventions that incur the smallest cumulative regret with respect to an oracle aware of the entire causal model and its fluctuations.

General Identifiability and Achievability for Causal Representation Learning

1 code implementation24 Oct 2023 Burak Varici, Emre Acartürk, Karthikeyan Shanmugam, Ali Tajer

For identifiability, the paper establishes that perfect recovery of the latent causal model and variables is guaranteed under uncoupled interventions.

Representation Learning

Optimal Best Arm Identification with Fixed Confidence in Restless Bandits

no code implementations20 Oct 2023 P. N. Karthik, Vincent Y. F. Tan, Arpan Mukherjee, Ali Tajer

It is shown that under every policy, the state-action visitation proportions satisfy a specific approximate flow conservation constraint and that these proportions match the optimal proportions dictated by the lower bound under any asymptotically optimal policy.

Spectral Adversarial MixUp for Few-Shot Unsupervised Domain Adaptation

1 code implementation3 Sep 2023 Jiajin Zhang, Hanqing Chao, Amit Dhurandhar, Pin-Yu Chen, Ali Tajer, Yangyang Xu, Pingkun Yan

To accomplish this challenging task, first, a spectral sensitivity map is introduced to characterize the generalization weaknesses of models in the frequency domain.

Unsupervised Domain Adaptation

GRNN-based Real-time Fault Chain Prediction

no code implementations15 Mar 2023 Anmol Dwivedi, Ali Tajer

The search process is formalized as a partially observable Markov decision process (POMDP), which is subsequently solved via a time-varying graph recurrent neural network (GRNN) that judiciously accounts for the inherent temporal and spatial structures of the data generated by the system.

Score-based Causal Representation Learning with Interventions

no code implementations19 Jan 2023 Burak Varici, Emre Acarturk, Karthikeyan Shanmugam, Abhishek Kumar, Ali Tajer

The objectives are: (i) recovering the unknown linear transformation (up to scaling) and (ii) determining the directed acyclic graph (DAG) underlying the latent variables.

Representation Learning valid

Best Arm Identification in Stochastic Bandits: Beyond $β-$optimality

no code implementations10 Jan 2023 Arpan Mukherjee, Ali Tajer

Two key metrics for assessing bandit algorithms are computational efficiency and performance optimality (e. g., in sample complexity).

Computational Efficiency Multi-Armed Bandits

Causal Bandits for Linear Structural Equation Models

1 code implementation26 Aug 2022 Burak Varici, Karthikeyan Shanmugam, Prasanna Sattigeri, Ali Tajer

Two linear mechanisms, one soft intervention and one observational, are assumed for each node, giving rise to $2^N$ possible interventions.

Thompson Sampling

Active Sampling of Multiple Sources for Sequential Estimation

no code implementations10 Aug 2022 Arpan Mukherjee, Ali Tajer, Pin-Yu Chen, Payel Das

Additionally, each process $i\in\{1, \dots, K\}$ has a private parameter $\alpha_i$.

SPRT-based Efficient Best Arm Identification in Stochastic Bandits

no code implementations22 Jul 2022 Arpan Mukherjee, Ali Tajer

Based on this test statistic, a BAI algorithm is designed that leverages the canonical sequential probability ratio tests for arm selection and is amenable to tractable analysis for the exponential family of bandits.

Multi-Armed Bandits Thompson Sampling

Best Arm Identification in Contaminated Stochastic Bandits

no code implementations NeurIPS 2021 Arpan Mukherjee, Ali Tajer, Pin-Yu Chen, Payel Das

Owing to the adversarial contamination of the rewards, each arm's mean is only partially identifiable.

Scalable Intervention Target Estimation in Linear Models

1 code implementation NeurIPS 2021 Burak Varici, Karthikeyan Shanmugam, Prasanna Sattigeri, Ali Tajer

This paper considers the problem of estimating the unknown intervention targets in a causal directed acyclic graph from observational and interventional data.

The Broadcast Approach in Communication Networks

no code implementations18 Jan 2021 Ali Tajer, Avi Steiner, Shlomo Shamai

However, when the variations are infrequent, their temporal average can deviate significantly from the channel's ergodic mode, rendering a lack of instantaneous performance guarantees.

Information Theory Information Theory

Structure Learning with Side Information: Sample Complexity

no code implementations NeurIPS 2019 Saurabh Sihag, Ali Tajer

Leveraging such side information can be abstracted as inferring structures of distinct graphical models that are {\sl partially} similar.

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