I am an assistant research professor in the Department of Computer Science at the University of Colorado Boulder. I am affilited with the Programming Languages and Verification Group and the Theory Group at the University of Colorado Boulder. I am also the instructor for the course Introduction to the Theory of Computation (CSCI 5444).
- Along with Sadegh Soudjani, I am co-organzing V2CPS-2017 colocated with iFM 2017 in Torino, Italy.
- Along with Krishna S., I am co-organzing AVeRTS-2017 workshop colocated with ICALP 2017 in Warsaw, Poland.
- I am offering CSCI 5444 (Introduction to Theory of Computation) in Spring 2017.
- Post-workshop proceedings of V2CPS are now available at 10.4204/EPTCS.232 .
- Paper Analyzing neighborhoods of falsifying traces in cyber-physical systems is accepted for ICCPS 2017.
- Paper Discriminating traces with time is accepted for TACAS 2017.
- Krishna S. and I organized AVeRTS (Algorithmic Verification of Real-Time Systems)—as a post-conference workshop of FSTTCS 2016—on December 16, 2016 at CMI, Chennai. Details of the 2015 edition of AVeRTS can be found here .
- Paper FO-definable transformations of infinite strings accepted to FSTTCS 2016.
- Paper Mean-Payoff Games on Timed Automata accepted to FSTTCS 2016.
Current Research.Keywords: Formal Methods, Game Theory, Cyber-Physical Systems, Automata Theory and Logic
I am actively working on the following research projects:
- Space/Time Analaysis for Cybersecurity.
The goal of this DARPA-sponsored project is to develop new program analysis
techniques to allow analysts to discover Java applications with exploitable
security vulnerabilities such as availability
(denial-of-service) and confidentiality (side-channels) vulnerabilities due to space and time usage
of the programs.
In identifying availability and confidentiality
problems, our focus is to minimize both false positives and false negatives.
In addition, it is often desirable that every identified vulnerability is
presented with sufficient evidence towards an exploit of
the vulnerability. In the case of availability problems, such evidence should
be in the form of an input that triggers excessive resource usage, while for
confidentiality problems, such evidence may a be pair of inputs that result in
differential resource usage.
I am particularly interested in combining static analysis techniques with
run-time analysis to pinpoint program vulnerabilities.
In one of our recent publications , we present a new run-time analysis
technique for debugging Java bytecode to uncover potential causes for
side-channels in time.
Related publications : .
- Counterexample Sensitivity-analysis for Cyber-Physical Systems. In this
Toyota-sponsored project, I investigate simulation-based approaches to analyze a given set of counterexamples to
correctness properties of CPS towards explaining and widening the
counterexamples to assist the system designer in further debugging.
The resulting approach can be used by engineers to
debug their CPS designs inside practical environments such as Simulink/Stateflow
Our approach extends classical sensitivity analysis to generalize neighborhood
of counterexamples by computing a box neighborhood around the original
counterexample so that sampling inputs in our neighborhood is highly likely to
also produce a counterexample. The effectiveness of this approach was
demonstrated over many CPS models including automotive and closed-loop medical
device control systems.
Related publications : .
- Theory of Stochastic Hybrid Structures.
The problem of mathematically modeling CPS is fundamental to analyzing their
safety and security properties. However, CPS integrate many different
aspects including time-criticality, nondeterminism,
presence of multiple
rational agents, rich continuous dynamics, stochastic behavior, and
higher-level programming constructs such as heaps and recursion. This poses
a fundamental challenge: a rich combination of these features yields models
that are too complex to reason about. In this project I study several useful
restrictions to these models to characterize the
decidability/undecidability frontier as well as exact computational
complexity of various verification and synthesis related questions.
Parts of this projects were sponsored by a Liverpool-India fellowship,
an IIT Bombay seed-grant, and the Indo-french project AVeRTS.
Related publications : , , , , and .
Talk (Video) : Multi-Mode Systems.
- Theory of Streaming String Transducers.
The beautiful theory of regular languages is the cornerstone of theoretical
computer science and formal language theory. The perfect harmony among the
languages of finite words definable using
abstract machines (deterministic
finite automata), algebra (regular expressions and finite monoids), and logic (monadic
second-order logic) did set the stage for the generalizations of the
theory to the theory of regular languages of infinite words,
trees, and partial orders.
Alur and Cerny have proposed a model of transducers, called
streaming string transducers, that for regular transformations seems
to be as appealing model as deterministic finite automata for regular languages.
The goal of this project is to study theoretical properties of streaming string
transducers and their applications in verification of CPS.
This project has been supported by the NSF Expeditions in Computing award
1138996 and an IITB seed-grant.
Related publications : , , , and .
Discriminating Traces with Time
Saeid Tizpaz-Niari, Pavol Cerny, Bor-Yuh Evan Chang, Sriram Sankaranarayanan, and Ashutosh Trivedi
In Proc. of International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS 2017).
Mean-Payoff Games on Timed Automata .
Shibashis Guha, Marcin Jurdzinski, Krishna S. and Ashutosh Trivedi.
In Proc. of Foundations of Software Technology and Theoretical Computer Science, FSTTCS 2016.
Symmetric Strategy Improvment .
Sven Schewe, Ashutosh Trivedi, Thomas Varghese.
In Proc. of the 42nd International Colloquium on Automata, Languages, and Programming (ICALP 2015).
Regular Transformations of Infinite
Rajeev Alur, Emmanuel Filiot, and Ashutosh Trivedi.
Proceedings of the 27th Annual IEEE/ACM Symposium on Logic in Computer Science, LICS 2012.
Optimal Scheduling for Constant-Rate
Rajeev Alur, Ashutosh Trivedi, and Dominik Wojtczak.
Proceedings of the 15th ACM international conference on Hybrid Systems: Computation and Control, HSCC 2012.
Best paper award, HSCC, CPS Week 2012.
Recursive Timed Automata.
Ashutosh Trivedi and Dominik Wojtczak.
Proceedings of 8th International Symposium on Automated Technology for Verification and Analysis, ATVA 2010.
Reachability-Time Games on Timed Automata
Marcin Jurdzinski and Ashutosh Trivedi.
Proceedings of 34th International Colloquium on Automata, Languages and Programming, ICALP 2007.