154 research outputs found
A Generalized Hybrid Hoare Logic
Deductive verification of hybrid systems (HSs) increasingly attracts more
attention in recent years because of its power and scalability, where a
powerful specification logic for HSs is the cornerstone. Often, HSs are
naturally modelled by concurrent processes that communicate with each other.
However, existing specification logics cannot easily handle such models. In
this paper, we present a specification logic and proof system for Hybrid
Communicating Sequential Processes (HCSP), that extends CSP with ordinary
differential equations (ODE) and interrupts to model interactions between
continuous and discrete evolution. Because it includes a rich set of algebraic
operators, complicated hybrid systems can be easily modelled in an algebra-like
compositional way in HCSP. Our logic can be seen as a generalization and
simplification of existing hybrid Hoare logics (HHL) based on duration calculus
(DC), as well as a conservative extension of existing Hoare logics for
concurrent programs. Its assertion logic is the first-order theory of
differential equations (FOD), together with assertions about traces recording
communications, readiness, and continuous evolution. We prove continuous
relative completeness of the logic w.r.t. FOD, as well as discrete relative
completeness in the sense that continuous behaviour can be arbitrarily
approximated by discretization. Besides, we discuss how to simplify proofs
using the logic by providing a simplified assertion language and a set of sound
and complete rules for differential invariants for ODEs. Finally, we implement
a proof assistant for the logic in Isabelle/HOL, and apply it to verify two
case studies to illustrate the power and scalability of our logic
Uniform Substitution for Dynamic Logic with Communicating Hybrid Programs
This paper introduces a uniform substitution calculus for
, the dynamic logic of communicating hybrid programs.
Uniform substitution enables parsimonious prover kernels by using axioms
instead of axiom schemata. Instantiations can be recovered from a single proof
rule responsible for soundness-critical instantiation checks rather than being
spread across axiom schemata in side conditions. Even though communication and
parallelism reasoning are notorious for necessitating subtle soundness-critical
side conditions, uniform substitution when generalized to
manages to limit and isolate their conceptual
overhead. Since uniform substitution has proven to simplify the implementation
of hybrid systems provers substantially, uniform substitution for
paves the way for a parsimonious implementation of
theorem provers for hybrid systems with communication and parallelism.Comment: CADE 202
Towards Verification of Cyber-Physical Systems with UTP and Isabelle/HOL
In this paper, we outline our vision for building verification tools for Cyber-Physical Systems based on Hoare and He’s Unifying Theories of Programming (UTP) and interactive proof technology in Isabelle/HOL. We describe our mechanisation and explain some of the design decisions that we have taken to get a convenient and smooth implementation. In particular, we describe our use of lenses to encode state. We illustrate our work with an example UTP theory and describe the implementation of three foundational theories: designs, reactive processes, and the hybrid relational calculus. We conclude by reflecting on how tools are linked by unifying theories
Modular Analysis of Distributed Hybrid Systems using Post-Regions (Full Version)
We introduce a new approach to analyze distributed hybrid systems by a
generalization of rely-guarantee reasoning. First, we give a system for
deductive verification of class invariants and method contracts in
object-oriented distributed hybrid systems. In a hybrid setting, the object
invariant must not only be the post-condition of a method, but also has to hold
in the post-region of a method. The post-region describes all reachable states
after method termination before another process is guaranteed to run. The
system naturally generalizes rely-guarantee reasoning of discrete
object-oriented languages to hybrid systems and carries over its modularity to
hybrid systems: Only one dL-proof obligation is generated per method. The
post-region can be approximated using lightweight analyses and we give a
general notion of soundness for such analyses. Post-region based verification
is implemented for the Hybrid Active Object language HABS
Proceedings of the First NASA Formal Methods Symposium
Topics covered include: Model Checking - My 27-Year Quest to Overcome the State Explosion Problem; Applying Formal Methods to NASA Projects: Transition from Research to Practice; TLA+: Whence, Wherefore, and Whither; Formal Methods Applications in Air Transportation; Theorem Proving in Intel Hardware Design; Building a Formal Model of a Human-Interactive System: Insights into the Integration of Formal Methods and Human Factors Engineering; Model Checking for Autonomic Systems Specified with ASSL; A Game-Theoretic Approach to Branching Time Abstract-Check-Refine Process; Software Model Checking Without Source Code; Generalized Abstract Symbolic Summaries; A Comparative Study of Randomized Constraint Solvers for Random-Symbolic Testing; Component-Oriented Behavior Extraction for Autonomic System Design; Automated Verification of Design Patterns with LePUS3; A Module Language for Typing by Contracts; From Goal-Oriented Requirements to Event-B Specifications; Introduction of Virtualization Technology to Multi-Process Model Checking; Comparing Techniques for Certified Static Analysis; Towards a Framework for Generating Tests to Satisfy Complex Code Coverage in Java Pathfinder; jFuzz: A Concolic Whitebox Fuzzer for Java; Machine-Checkable Timed CSP; Stochastic Formal Correctness of Numerical Algorithms; Deductive Verification of Cryptographic Software; Coloured Petri Net Refinement Specification and Correctness Proof with Coq; Modeling Guidelines for Code Generation in the Railway Signaling Context; Tactical Synthesis Of Efficient Global Search Algorithms; Towards Co-Engineering Communicating Autonomous Cyber-Physical Systems; and Formal Methods for Automated Diagnosis of Autosub 6000
- …