194,791 research outputs found
Future-based Static Analysis of Message Passing Programs
Message passing is widely used in industry to develop programs consisting of
several distributed communicating components. Developing functionally correct
message passing software is very challenging due to the concurrent nature of
message exchanges. Nonetheless, many safety-critical applications rely on the
message passing paradigm, including air traffic control systems and emergency
services, which makes proving their correctness crucial. We focus on the
modular verification of MPI programs by statically verifying concrete Java
code. We use separation logic to reason about local correctness and define
abstractions of the communication protocol in the process algebra used by
mCRL2. We call these abstractions futures as they predict how components will
interact during program execution. We establish a provable link between futures
and program code and analyse the abstract futures via model checking to prove
global correctness. Finally, we verify a leader election protocol to
demonstrate our approach.Comment: In Proceedings PLACES 2016, arXiv:1606.0540
A bunch of sessions:a propositions-as-sessions interpretation of bunched implications in channel-based concurrency
The emergence of propositions-as-sessions, a Curry-Howard correspondence between propositions of Linear Logic and session types for concurrent processes, has settled the logical foundations of message-passing concurrency. Central to this approach is the resource consumption paradigm heralded by Linear Logic. In this paper, we investigate a new point in the design space of session type systems for message-passing concurrent programs. We identify O’Hearn and Pym’s Logic of Bunched Implications (BI) as a fruitful basis for an interpretation of the logic as a concurrent programming language. This leads to a treatment of non-linear resources that is radically different from existing approaches based on Linear Logic. We introduce a new π-calculus with sessions, called πBI; its most salient feature is a construct called spawn, which expresses new forms of sharing that are induced by structural principles in BI. We illustrate the expressiveness of πBI and lay out its fundamental theory: type preservation, deadlock-freedom, and weak normalization results for well-typed processes; an operationally sound and complete typed encoding of an affine λ-calculus; and a non-interference result for access of resources
Modal Logic and Distributed Message Passing Automata
In a recent article, Lauri Hella and co-authors identify a canonical connection between modal logic and deterministic distributed constant-time algorithms. The paper reports a variety of highly natural logical characterizations of classes of distributed message passing automata that run in constant time. The article leaves open the question of identifying related logical characterizations when the constant running time limitation is lifted. We obtain such a characterization for a class of finite message passing automata in terms of a recursive bisimulation invariant logic which we call modal substitution calculus (MSC). We also give a logical characterization of the related class A of infinite message passing automata by showing that classes of labelled directed graphs recognizable by automata in A are exactly the classes co-definable by a modal theory. A class C is co-definable by a modal theory if the complement of C is definable by a possibly infinite set of modal formulae. We also briefly discuss expressivity and decidability issues concerning MSC. We establish that MSC contains the Sigma^mu_1 fragment of the modal mu-calculus in the finite. We also observe that the single variable fragment MSC^1 of MSC is not contained in MSO, and that the SAT and FINSAT problems of MSC^1 are complete for PSPACE
MoCheQoS: Automated Analysis of Quality of Service Properties of Communicating Systems
We present MoCheQoS, a tool to analyse quality of service (QoS) properties of
message-passing systems. Building on the logic and the choreographic model we
defined in recently published work, MoCheQoS implements a bounded model
checking algorithm. We discuss strengths and weaknesses of MoCheQoS through
some case studies.Comment: 29 page
Asymptotically MDS Array BP-XOR Codes
Belief propagation or message passing on binary erasure channels (BEC) is a
low complexity decoding algorithm that allows the recovery of message symbols
based on bipartite graph prunning process. Recently, array XOR codes have
attracted attention for storage systems due to their burst error recovery
performance and easy arithmetic based on Exclusive OR (XOR)-only logic
operations. Array BP-XOR codes are a subclass of array XOR codes that can be
decoded using BP under BEC. Requiring the capability of BP-decodability in
addition to Maximum Distance Separability (MDS) constraint on the code
construction process is observed to put an upper bound on the maximum
achievable code block length, which leads to the code construction process to
become a harder problem. In this study, we introduce asymptotically MDS array
BP-XOR codes that are alternative to exact MDS array BP-XOR codes to pave the
way for easier code constructions while keeping the decoding complexity low
with an asymptotically vanishing coding overhead. We finally provide and
analyze a simple code construction method that is based on discrete geometry to
fulfill the requirements of the class of asymptotically MDS array BP-XOR codes.Comment: 8 pages, 4 figures, to be submitte
Asymptotically MDS Array BP-XOR Codes
Belief propagation or message passing on binary erasure channels (BEC) is a
low complexity decoding algorithm that allows the recovery of message symbols
based on bipartite graph prunning process. Recently, array XOR codes have
attracted attention for storage systems due to their burst error recovery
performance and easy arithmetic based on Exclusive OR (XOR)-only logic
operations. Array BP-XOR codes are a subclass of array XOR codes that can be
decoded using BP under BEC. Requiring the capability of BP-decodability in
addition to Maximum Distance Separability (MDS) constraint on the code
construction process is observed to put an upper bound on the maximum
achievable code block length, which leads to the code construction process to
become a harder problem. In this study, we introduce asymptotically MDS array
BP-XOR codes that are alternative to exact MDS array BP-XOR codes to pave the
way for easier code constructions while keeping the decoding complexity low
with an asymptotically vanishing coding overhead. We finally provide and
analyze a simple code construction method that is based on discrete geometry to
fulfill the requirements of the class of asymptotically MDS array BP-XOR codes.Comment: 8 pages, 4 figures, to be submitte
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