Department of Computational and Data Sciences
Department Seminar
Speaker : Mr. Gaurang Sriramanan, PhD candidate at the University of Maryland,
Title : Deceptive Plausibility: Investigating Visual Blind Spots and LLM Hallucinations
Date & Time: February 05th, 2026 (Thursday), 04:00 PM
Venue : # 102, CDS Seminar Hall
ABSTRACT
As AI models are increasingly deployed in safety-critical sectors, characterizing their failure modes is essential for building trustworthy systems. This talk explores two critical vulnerabilities: the under-sensitivity of computer vision models and the phenomenon of hallucinations in Large Language Models (LLMs).
First, we analyze model undersensitivity—the failure of a system to recognize meaningful, large-scale changes in its input. While most existing research focuses on oversensitivity to imperceptible noise (adversarial attacks), we identify “blind spots” using a novel Level Set Traversal (LST) algorithm. By navigating the geometry of model level sets, we reveal linearly connected paths between images that a human oracle would deem extremely disparate, yet the model maintains near-uniform confidence, exposing a fundamental gap in machine perception.
Second, we address hallucinations in LLMs—outputs that are fabricated yet appear deceptively plausible. We present LLM-Check, a suite of efficient techniques that detect these errors by leveraging internal hidden representations, attention similarity maps, and logit outputs. We demonstrate its efficacy across broad settings, from zero-resource detection to scenarios where multiple model generations or external databases are available, all without incurring significant computational overhead.
BIO: Gaurang Sriramanan is a CS PhD candidate at the University of Maryland, advised by Prof. Soheil Feizi. His research focuses on AI safety and reliability by characterizing model failure modes and developing robust mitigation strategies. Previously a Student Researcher at Meta, he holds an M.S. from UMD and a B.S./M.Sc. in Mathematics from IISc.
Host Faculty: Prof. Venkatesh Babu
ALL ARE WELCOME
