3,053 research outputs found
The foundational legacy of ASL
Abstract. We recall the kernel algebraic specification language ASL and outline its main features in the context of the state of research on algebraic specification at the time it was conceived in the early 1980s. We discuss the most significant new ideas in ASL and the influence they had on subsequent developments in the field and on our own work in particular.
Mechanizing a Process Algebra for Network Protocols
This paper presents the mechanization of a process algebra for Mobile Ad hoc
Networks and Wireless Mesh Networks, and the development of a compositional
framework for proving invariant properties. Mechanizing the core process
algebra in Isabelle/HOL is relatively standard, but its layered structure
necessitates special treatment. The control states of reactive processes, such
as nodes in a network, are modelled by terms of the process algebra. We propose
a technique based on these terms to streamline proofs of inductive invariance.
This is not sufficient, however, to state and prove invariants that relate
states across multiple processes (entire networks). To this end, we propose a
novel compositional technique for lifting global invariants stated at the level
of individual nodes to networks of nodes.Comment: This paper is an extended version of arXiv:1407.3519. The
Isabelle/HOL source files, and a full proof document, are available in the
Archive of Formal Proofs, at http://afp.sourceforge.net/entries/AWN.shtm
Compositional Set Invariance in Network Systems with Assume-Guarantee Contracts
This paper presents an assume-guarantee reasoning approach to the computation
of robust invariant sets for network systems. Parameterized signal temporal
logic (pSTL) is used to formally describe the behaviors of the subsystems,
which we use as the template for the contract. We show that set invariance can
be proved with a valid assume-guarantee contract by reasoning about individual
subsystems. If a valid assume-guarantee contract with monotonic pSTL template
is known, it can be further refined by value iteration. When such a contract is
not known, an epigraph method is proposed to solve for a contract that is
valid, ---an approach that has linear complexity for a sparse network. A
microgrid example is used to demonstrate the proposed method. The simulation
result shows that together with control barrier functions, the states of all
the subsystems can be bounded inside the individual robust invariant sets.Comment: Submitted to 2019 American Control Conferenc
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