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Sihat Afnan

PhD Researcher at UC Irvine

Hi! I am Sihat Afnan, a PhD Researcher in the CSE Department of University of California, Irvine. I graduated from the Department of Computer Science and Engineering at Bangladesh University of Engineering and Technology (BUET).

I enjoy outdoor activities (e.g. jogging, travelling), reading non-fiction, Op-Eds, and listening to qawali music.

Research Areas

My research investigates security and privacy issues in the perception modules of emerging systems, including AR/VR headsets, autonomous vehicles, and embodied AI such as humanoid robotics. I study how the cameras, depth sensors, microphones, and motion data these systems rely on can be manipulated by adversaries or leak sensitive information about their users, and I build measurement frameworks and defenses that expose these risks before deployment.

Education

  • PhD in Computer Science (2024 - Present)

    University of California, Irvine

  • Bachelor of Science in Computer Science (2018 - 2023)

    Bangladesh University of Engineering and Technology




Professional Experience

Graduate Student Researcher

Conducting research on security and privacy of perception modules in emerging systems, including AR/VR, autonomous vehicles, and embodied AI.

Graduate Teaching Assistant

Assisted in teaching CS 130 (Introduction to Computer Security), ICS 33 (Intermediate Programming with Python), and ICS H32 (Python Programming with Libraries - Accelerated).

Lecturer

Department of CSE
School of Data and Sciences
BRAC University

Taught courses on Computer Architecture, Microprocessor, Operating Systems and Discrete Mathematics

Machine Learning Engineer

Deployed Mathematical models, built machine learning tools and devised financial engineering solutions




Research Experience

Security/Privacy of Robotics

Showed that human-to-humanoid motion retargeting, which projects operator demonstrations onto a shared robot skeleton and discards body shape, fails to anonymize the operator: while it normalizes body proportions, it preserves movement dynamics shaped by the operator's physiology. Demonstrated that retargeted trajectories support accurate gender classification, operator reidentification, and age/height regression even for unseen operators, with signals that are task-invariant and consistent across retargeting implementations. Introduced UNVEIL, a skeleton-aware spatiotemporal graph network to measure and interpret this effect, raising a privacy concern for the robotics community: as teleoperation datasets are increasingly shared and scaled, retargeted trajectories can act as a biometric fingerprint exposing sensitive operator attributes.

Project Page: project-unveil.github.io

Status: Under review at NeurIPS 2026

Security of AR/VR Systems

Investigated the security of XR spatial understanding pipelines by designing the first on-device acoustic attack that uses only a headset's built-in speakers to subtly manipulate 3D scene reconstruction. Modeled how injected acoustic interference perturbs camera odometry, RGB imaging, and depth sensing, and developed an optimization framework that generates perturbations causing controlled geometric distortions in the spatial map. Demonstrated impactful effects including object addition/removal, surface misclassification, and degraded user task performance across Meta Quest 3S, Apple iPad, and ARIA glasses, with real-world experiments on Quest 3S showing corruption in over 91% of spatial maps.

Status: Under review at MobiCom 2026

Autonomous Vehicle Security

Developing a high-fidelity VR simulation framework using CARLA to study how human drivers perceive and react to autonomous vehicle misbehavior caused by sensor-level perception attacks such as stop sign manipulation, lane detection failures, and phantom obstacles. The project integrates a realistic AV stack, including sensor simulation, machine-learning based perception, planning, and control, together with real-time eye-tracking and behavioral logging. This work addresses key challenges in synchronizing multi-modal sensor data, attack injection, and human–autonomy interaction in VR, enabling systematic evaluation of AV safety under adversarial conditions.

Status: Under review at IEEE S&P 2027

LLM Based Threat Detection

A framework designed to detect APT attack patterns leveraging the power of self-attention in transformers. We incorporate customized embedding layers to effectively capture the context of event sequences derived from provenance graphs. While acknowledging the computational overhead associated with training transformer networks, our framework surpasses existing LSTM and Language models regarding APT detection performance. We integrated the model parameters and training procedure from the RoBERTa model and conducted extensive experiments on well-known APT datasets (DARPA OpTC and DARPA TC E3). Our framework achieved superior F1 scores of 98% and 95% on the two datasets respectively, surpassing the F1 scores of 96% and 94% obtained by LSTM models. Our findings suggest that LogShield's performance benefits from larger datasets and demonstrates its potential for generalization across diverse domains.

Status: ArXiv




Coursework

Graduate Courses at UC Irvine

  • CS 295 — Robotics Deep Learning. Neural-network methods for robot perception and control, including imitation and reinforcement learning, policy learning, and sim-to-real transfer.
  • CS 205 — Computer and Systems Security. Research-paper seminar on attacks and defenses across OS, software, ML, mobile, sensors, and emerging IoT/CPS platforms, with a quarter-long research project.
  • CS 203 — Network and Distributed Systems Security. Threats and defenses across networked and distributed systems, covering authentication, identification, secrecy, integrity, and access control.
  • CS 273A — Machine Learning. Foundations of supervised learning — regression, decision trees, nearest neighbor, linear models, and naive Bayes — with Python implementation assignments.
  • CS 256 — Systems and ML. Two-part course on systems built to accelerate ML training and inference, and on applying ML inside computer systems (scheduling, networking, OS).
  • CS 216 — Image Understanding. Pulling semantic information from images and video: low-level processing, feature descriptors, segmentation, recognition, and tracking.
  • CS 244 — Embedded and Ubiquitous Systems. Embedded processors, DSP, sensors and actuators, and wireless communication, with case studies in mobile, multimedia, and networking platforms.
  • CS 204 — Usable Security and Privacy. Designing security and privacy mechanisms from a user-centered perspective, blending systems methods with human-factors research.
  • CS 232 — Computer Networks. Internet, cellular, and cable network architectures with a focus on congestion control, addressing, routing, and quality of service.



Class Projects

 
 
 
 
 

Flow classification on Programmable Data Plane using P4 Switch

Classifying network flows at an early stage primarily based on size of the flow, count of packets, inter-arrival time, and duration of the flow. The ML technique considered is decision trees since it can be easily implemented in PISA Architecture.
[Code]

 
 
 
 
 

Improving RTT & RTO

Open source implementation of Peak-Hopper: A New End-to-End Retransmission Timer for Reliable Unicast Transport. It improves the performance of retransmission timer specified in [RFC2988] using the network simulator NS3.
[Code]

 
 
 
 
 

Bengali Complex Named Entity Recognition

Identifications and classification of named entities in Bangla language texts using the BERT model. The project is designed to be used in various applications such as text analytics and information retrieval systems.
[Code]

 
 
 
 
 

Operating Systems Projects

Course Project

Adding syscall, threading and scheduling in XV6, implementing Linux shell, implementation of Memory Management Module of XV6.
[Code]

 
 
 
 
 

Pipelined MIPS-like Processor

Course Project

Implemented an 8-bit processor that supports pipelined datapath for a subset of MIPS instruction set.
[Code]

 
 
 
 
 

A Smart Stick for Blind People with object detection and direction guidance

Course Project

Built a SmartStick for the blind with an embedded system constructed of ATMega32 microcontroller and various sensors mounted on it for obstacle detection and direction guidance.
[Demo]

 
 
 
 
 

Ray Tracing from scratch using OpenGL

Course Project

A ray tracer shoots rays from the observer’s eye through a screen and into a scene of objects. It calculates the ray’s intersection with objects, finds the nearest intersection and calculates the color of the surface according to its material and lighting conditions.
[Code]







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Awards

  • Computer Science Department Research Fellowship (UCI) — Graduate Fellow
  • University Dean's List Scholarship (BUET), 2019-2023
  • University Merit Scholarship (BUET), 2018-2023
  • Champion in an international Grammatical Error Detection Competition
  • 2nd Runner Up in NLP Hackathon-2023 hosted by Bangladesh Open Source Network
  • 1st Runner Up in HackNSU 2020 organized by NSU ACM Student Chapter
  • Placed in Top Seven of HackTheVerse 2020 hosted by IIT,DU
  • Program Committee member in BEA-ACL 2023 Conference Workshop
  • Talentpool Scholarship (HSC/O Level) ; 8th position in Dhaka Board
  • Talentpool Scholarship (SSC/A level) ; 20th position in Dhaka Board
  • Coordinator and Problem Setter in ICT Olympiad of St. Joseph High School, Dhaka



Contact

  • sihata@uci.edu
  • ICS Building 1, Room 430B, Donald Bren School of Information & Computer Sciences, University of California, Irvine, CA 92697