Sai Shankar Narasimhan

I am a fifth year graduate student in the University of Texas at Austin, pursuing PhD in ECE. I am advised by Prof. Sandeep Chinchali. My research focuses on synthetic time-series data generation using diffusion-based multimodal models, and on improving forecasting by incorporating exogenous signals such as news and social media. Previously, I was a Research Assistant at Robotics Research Centre, IIIT, Hyderabad, working under Madhava Krishna.

I received my undergraduate degree in Electrical Engineering at Anna University in India, with my Bachelor's thesis advised by Ranganath Muthu. My Research Internship at IIT Madras, with P.V.Manivannan, was focussed on SLAM. I have also worked full-time for over a year at Swaayatt Robots.

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News
  • Nov 2025: I have successfully completed my PhD Progress Review!
  • Sep 2025: I will be presenting Constrained Posterior Sampling for Time-Series Data Generation at NeurIPS 2025
  • May 2025: I will be interning at Synthefy on developing multivariate time series forecasting foundation models
  • May 2024: I will be presenting Time Weaver (Spotlight Talk) at ICML 2024
  • Nov 2023: I will be presenting my work on Safe Networked Control as an Oral talk at ICRA 2024
  • Sep 2023: Started my PhD at UT Austin under the supervision of Prof. Sandeep Chinchali
  • Sep 2021: I joined UT Austin as an MS student in ECE
  • June 2020: AutoLay, our benchmark for amodal layout estimation was accepted for IROS 2020
  • Jan 2020: Our work, Deep Flow guided IBVS will be presented in ICRA 2020
  • Dec 2019: Our work MonoLayout was accepted for WACV 2020
  • June 2019: Joined Robotics Research Centre at IIIT-Hyderabad as Research Assistant

Research
Constrained Posterior Sampling: Time Series Generation with Hard Constraints
Sai Shankar Narasimhan, Shubhankar Agarwal, Litu Rout, Sanjay Shakkottai, Sandeep Chinchali
NeurIPS 2025
paper

We propose Constrained Posterior Sampling (CPS), a principled framework for generating realistic synthetic time series data that provably satisfies user-specified hard constraints such as physics laws and operational limits.

Time Weaver: A Conditional Time Series Generation Model
Sai Shankar Narasimhan, Shubhankar Agarwal, Oguzhan Akcin, Sujay Sanghavi, Sandeep Chinchali
ICML 2024   (Spotlight)
paper

We present Time Weaver, a novel diffusion-based model for conditional time series generation that can generate realistic synthetic time series data conditioned on scenario-specific descriptions and metadata.

Safe Networked Robotics with Probabilistic Verification
Sai Shankar Narasimhan, Sharachchandra Bhat, Sandeep Chinchali
IEEE Robotics and Automation Letters (RA-L) 2024 | ICRA 2024   (Oral)
paper

We propose a principled framework for safe networked control of robotic systems using probabilistic verification to provide safety guarantees under network impairments such as delays and packet losses.

AutoLay: Benchmarking Monocular Layout Estimation
Kaustubh Mani*, N. Sai Shankar*, Krishna Murthy, K. Madhava Krishna,
IROS 2020
Also presented in PAD Workshop, ECCV 2020
workshop page | project page | paper

We introduce AutoLay, a new dataset for amodal layout estimation in bird’s eye view. Further, we propose VideoLayout, a real-time neural net architecture that leverages temporal information from monocular video, to produce more accurate and consistent layouts.

MonoLayout: Amodal Scene Layout from a single image
Kaustubh Mani, Swapnil Daga, Shubhika Garg, N. Sai Shankar, J. Krishna Murthy, K. Madhava Krishna,
WACV 2020
project page | paper | code | video

We present MonoLayout, a deep neural network for real-time amodal scene layout estimation from a single image. We leverage adversarial feature learning to hallucinate plausible completions for occlusions.

DFVS: Deep Flow Guided Scene Agnostic Image Based Visual Servoing
Y V S Harish, Harit Pandya, Ayush Gaud, Shreya Terupally, Sai Shankar, K. Madhava Krishna,
ICRA 2020
project page | paper | code

We propose a novel system consisting of deep neural networks that systematically integrates depth cues with flow features.

Modified Extended Kalman Filter Using Correlations Between Measurement Parameters
Ramanan Sekar, Sai Shankar N, Shiva Shankar B, P.V.Manivannan,
International Conference on Computational Intelligence 2018
conference | paper | code

We propose a novel Kalman Filter (KF) algorithm, that leverages the statistical correlation between the measured variables.

Use of measurement noise correlations for an improved SONAR model
Ramanan Sekar, Sai Shankar N, Shiva Shankar B, P.V.Manivannan,
International Conference on Computational Intelligence 2018
conference | paper

We propose a solution to reduce the range and bearing error in SONARs significantly. Using the results from the Gaussian Correlation Inequality, we derive probabilistic transformations that can improve the measurements of the SONAR, thus reducing the sensor error.

Collaboration between Unmanned Aerial and Ground Vehicles for Search and Rescue Missions
Ramanan Sekar, Sai Shankar N, Shiva Shankar B,
Undergraduate Final Year Project
Supervised by Ranganath Muthu
report | presentation

We developed a collaborative Aerial Vehicle (UAV), Ground Vehicle (UGV) platform that can be used to aid / automate search and rescue missions in disaster zones.

Based on Ramanan's and Jon's webpages.