Evaluation of Parallel System Using Process Algebra
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Concepts of Concurrent Programming Summary of the Course in Spring 2011 by Bertrand Meyer and Sebastian Nanz
Concepts of Concurrent Programming Summary of the course in spring 2011 by Bertrand Meyer and Sebastian Nanz Stefan Heule 2011-05-28 Licence: Creative Commons Attribution-Share Alike 3.0 Unported (http://creativecommons.org/licenses/by-sa/3.0/) Contents 1 Introduction .......................................................................................................................................... 4 1.1 Ambdahl’s Law .............................................................................................................................. 4 1.2 Basic Notions ................................................................................................................................. 4 1.2.1 Multiprocessing ..................................................................................................................... 4 1.2.2 Multitasking .......................................................................................................................... 4 1.2.3 Definitions ............................................................................................................................. 4 1.2.4 The Interleaving Semantics ................................................................................................... 5 1.3 Transition Systems and LTL ........................................................................................................... 6 1.3.1 Syntax and Semantics of Linear-Time Temporal Logic.......................................................... 7 1.3.2 Safety and Liveness Properties -
Implementing a Transformation from BPMN to CSP+T with ATL: Lessons Learnt
Implementing a Transformation from BPMN to CSP+T with ATL: Lessons Learnt Aleksander González1, Luis E. Mendoza1, Manuel I. Capel2 and María A. Pérez1 1 Processes and Systems Department, Simón Bolivar University PO Box 89000, Caracas, 1080-A, Venezuela 2 Software Engineering Department, University of Granada Aynadamar Campus, 18071, Granada, Spain Abstract. Among the challenges to face in order to promote the use of tech- niques of formal verification in organizational environments, there is the possi- bility of offering the integration of features provided by a Model Transforma- tion Language (MTL) as part of a tool very used by business analysts, and from which formal specifications of a model can be generated. This article presents the use of MTL ATLAS Transformation Language (ATL) as a transformation artefact within the domains of Business Process Modelling Notation (BPMN) and Communicating Sequential Processes + Time (CSP+T). It discusses the main difficulties encountered and the lessons learnt when building BTRANSFORMER; a tool developed for the Eclipse platform, which allows us to generate a formal specification in the CSP+T notation from a business process model designed with BPMN. This learning is valid for those who are interested in formalizing a Business Process Modelling Language (BPML) by means of a process calculus or another formal notation. 1 Introduction Business Processes (BP) must be properly and formally specified in order to be able to verify properties, such as scope, structure, performance, capacity, structural consis- tency and concurrency, i.e., those properties of BP which can provide support to the critical success factors of any organization. Formal specification languages and proc- ess algebras, which allow for the exhaustive verification of BP behaviour [17], are used to carry out the formalization of models obtained from Business Process Model- ling (BPM). -
Bisimulations in the Join-Calculus
Bisimulations in the Join-Calculus C´edricFournet a Cosimo Laneve b,1 aMicrosoft Research, 1 Guildhall Street, Cambridge, U.K. b Dipartimento di Scienze dell’Informazione, Universit`adi Bologna, Mura Anteo Zamboni 7, 40127 Bologna, Italy. Abstract We develop a theory of bisimulations in the join-calculus. We introduce a refined operational model that makes interactions with the environment explicit, and dis- cuss the impact of the lexical scope discipline of the join-calculus on its extensional semantics. We propose several formulations of bisimulation and establish that all formulations yield the same equivalence. We prove that this equivalence is finer than barbed congruence, but that both relations coincide in the presence of name matching. Key words: asynchronous processes; barbed congruence; bisimulation; chemical semantics; concurrency; join-calculus; locality; name matching; pi-calculus. 1 Introduction The join-calculus is a recent formalism for modeling mobile systems [15,17]. Its main motivation is to relate two crucial issues in concurrency: distributed implementation and formal semantics. To this end, the join-calculus enforces a strict lexical scope discipline over the channel names that appear in processes: names can be sent and received, but their input capabilities cannot be affected by the receivers. This is the locality property. 2 Locality yields a realistic distributed model, because the communication prim- itives of the calculus can be directly implemented via standard primitives of 1 This work is partly supported by the ESPRIT CONFER-2 WG-21836 2 The term locality is a bit overloaded in the literature; here, names are locally defined inasmuch as no external definition may interfere; this is the original meaning of locality in the chemical semantics of Banˆatre et al. -
A Framework for Performance Evaluation and Verification in Stochastic Process Algebras
A Framework for Performance Evaluation and Functional Verification in Stochastic Process Algebras Hossein Hojjat MohammadReza Marjan Sirjani ∗ IPM and University of Tehran, Mousavi IPM and University of Tehran, Tehran, Iran TU/Eindhoven, Eindhoven, Tehran, Iran The Netherlands, and Reykjav´ık University, Reykjav´ık, Iceland ABSTRACT To make our goals concrete, we would like to translate Despite its relatively short history, a wealth of formalisms a number of SPAs which have similar semantic frameworks exist for algebraic specification of stochastic systems. The (e.g., PEPA [14], MTIPP [13], EMPA [4] and IMC [11]) goal of this paper is to give such formalisms a unifying frame- to a common form in the mCRL2 process algebra (which work for performance evaluation and functional verification. is a classic process algebra [2] enhanced with abstract data To this end, we propose an approach enabling a provably types). Our next milestone is to generate state space using sound transformation from some existing stochastic process the mCRL2 tool-set. Finally, we wish to be able to perform algebras, e.g., PEPA and MTIPP, to a generic form in the various functional- as well as performance-related analyses mCRL2 language. This way, we resolve the semantic dif- on the generated state space using available tools, as well as ferences among different stochastic process algebras them- tools that we develop for this purpose. selves, on one hand, and between stochastic process algebras For the ease of presentation, we shall focus on one of these and classic ones, such as mCRL2, on the other hand. From process algebras, namely PEPA (due to its popularity), in the generic form, one can generate a state space and perform the remainder of this paper and only touch upon the aspects various functional and performance-related analyses, as we in which our approach has to be adapted to fit the other pro- illustrate in this paper. -
Deadlock Analysis of Wait-Notify Coordination Laneve Cosimo, Luca Padovani
Deadlock Analysis of Wait-Notify Coordination Laneve Cosimo, Luca Padovani To cite this version: Laneve Cosimo, Luca Padovani. Deadlock Analysis of Wait-Notify Coordination. The Art of Modelling Computational Systems: A Journey from Logic and Concurrency to Security and Privacy - Essays Dedicated to Catuscia Palamidessi on the Occasion of Her 60th Birthday, Nov 2019, Paris, France. hal-02430351 HAL Id: hal-02430351 https://hal.archives-ouvertes.fr/hal-02430351 Submitted on 7 Jan 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Deadlock Analysis of Wait-Notify Coordination Cosimo Laneve1[0000−0002−0052−4061] and Luca Padovani2[0000−0001−9097−1297] 1 Dept. of Computer Science and Engineering, University of Bologna { INRIA Focus 2 Dipartimento di Informatica, Universit`adi Torino Abstract. Deadlock analysis of concurrent programs that contain co- ordination primitives (wait, notify and notifyAll) is notoriously chal- lenging. Not only these primitives affect the scheduling of processes, but also notifications unmatched by a corresponding wait are silently lost. We design a behavioral type system for a core calculus featuring shared objects and Java-like coordination primitives. The type system is based on a simple language of object protocols { called usages { to determine whether objects are used reliably, so as to guarantee deadlock freedom. -
The Beacon Calculus: a Formal Method for the flexible and Concise Modelling of Biological Systems
bioRxiv preprint doi: https://doi.org/10.1101/579029; this version posted November 26, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. The Beacon Calculus: A formal method for the flexible and concise modelling of biological systems Michael A. Boemo1∗ Luca Cardelli2 Conrad A. Nieduszynski3 1Department of Pathology, University of Cambridge 2Department of Computer Science, University of Oxford 3Genome Damage and Stability Centre, University of Sussex Abstract Biological systems are made up of components that change their actions (and interactions) over time and coordinate with other components nearby. Together with a large state space, the complexity of this behaviour can make it difficult to create concise mathematical models that can be easily extended or modified. This paper introduces the Beacon Calculus, a process algebra designed to simplify the task of modelling interacting biological components. Its breadth is demonstrated by creating models of DNA replication dynamics, the gene expression dynamics in response to DNA methylation damage, and a multisite phosphorylation switch. The flexibility of these models is shown by adapting the DNA replication model to further include two topics of interest from the literature: cooperative origin firing and replication fork barriers. The Beacon Calculus is supported with the open-source simulator bcs (https://github.com/MBoemo/bcs.git) to allow users to develop and simulate their own models. Author summary Simulating a model of a biological system can suggest ideas for future experiments and help ensure that conclusions about a mechanism are consistent with data. -
Proof-Relevant Π-Calculus
Proof-relevant π-calculus Roly Perera James Cheney University of Glasgow University of Edinburgh Glasgow, UK Edinburgh, UK [email protected] [email protected] Formalising the π-calculus is an illuminating test of the expressiveness of logical frameworks and mechanised metatheory systems, because of the presence of name binding, labelled transitions with name extrusion, bisimulation, and structural congruence. Formalisations have been undertaken in a variety of systems, primarily focusing on well-studied (and challenging) properties such as the theory of process bisimulation. We present a formalisation in Agda that instead explores the theory of concurrent transitions, residuation, and causal equivalence of traces, which has not previously been formalised for the π-calculus. Our formalisation employs de Bruijn indices and dependently- typed syntax, and aligns the “proved transitions” proposed by Boudol and Castellani in the context of CCS with the proof terms naturally present in Agda’s representation of the labelled transition relation. Our main contributions are proofs of the “diamond lemma” for residuation of concurrent transitions and a formal deVnition of equivalence of traces up to permutation of transitions. 1 Introduction The π-calculus [18, 19] is an expressive model of concurrent and mobile processes. It has been investigated extensively and many variations, extensions and reVnements have been proposed, including the asynchronous, polyadic, and applied π-calculus (among many others). The π-calculus has also attracted considerable attention from the logical frameworks and meta-languages community, and formalisations of its syntax and semantics have been performed using most of the extant mechanised metatheory techniques, including (among others) Coq [13, 12, 15], Nominal Isabelle [2], Abella [1] (building on Miller and Tiu [26]), CLF [6], and Agda [21]. -
A Time Constrained Real-Time Process Calculus
2008:33 LICENTIATE T H E SIS A Time Constrained Real-Time Process Calculus Viktor Leijon Luleå University of Technology Department of Computer Science and Electrical Engineering EISLAB Universitetstryckeriet, Luleå 2008:33|: 02-757|: -c -- 08 ⁄33 -- A Time Constrained Real-Time Process Calculus Viktor Leijon EISLAB Dept. of Computer Science and Electrical Engineering Lule˚a University of Technology Lule˚a, Sweden Supervisor: Johan Nordlander Jingsen Chen ii The night is darkening round me, The wild winds coldly blow; But a tyrant spell has bound me And I cannot, cannot go. - Emily Bront¨e iv Abstract There are two important questions to ask regarding the correct execution of a real-time program: (i) Is there a platform such that the program executes correctly? (ii) Does the program execute correctly on a particular platform? The execution of a program is correct if all actions are taken within their exe- cution window, i.e. after their release time but before their deadline. A program which executes correctly on a specific platform is said to be feasible on that plat- form and an incorrect program is one which is not feasible on any platform. In this thesis we develop a timed process calculus, based on the π-calculus, which can help answer these questions. We express the time window in which computation is legal by use of two time restrictions, before and after, to express a deadline and a release time offset respectively. We choose to look at correctness through the traces of the program. The trace of a program will always be a sequence of interleaved internal reductions and time steps, because programs have no free names. -
Πdist: Towards a Typed Π-Calculus for Distributed Programming Languages
πdist: Towards a Typed π-calculus for Distributed Programming Languages MSc Thesis (Afstudeerscriptie) written by Ignas Vyšniauskas (born May 27th, 1989 in Vilnius, Lithuania) under the supervision of Dr Wouter Swierstra and Dr Benno van den Berg, and submitted to the Board of Examiners in partial fulfillment of the requirements for the degree of MSc in Logic at the Universiteit van Amsterdam. Date of the public defense: Members of the Thesis Committee: Jan 30, 2015 Dr Benno van den Berg Prof Jan van Eijck Prof Christian Schaffner Dr Tijs van der Storm Dr Wouter Swierstra Prof Ronald de Wolf Abstract It is becoming increasingly clear that computing systems should not be viewed as isolated machines performing sequential steps, but instead as cooperating collections of such machines. The work of Milner and others shows that ’classi- cal’ models of computation (such as the λ-calculus) are encompassed by suitable distributed models of computation. However, while by now (sequential) com- putability is quite a rigid mathematical notion with many fruitful interpreta- tions, an equivalent formal treatment of distributed computation, which would be universally accepted as being canonical, seems to be missing. The goal of this thesis is not to resolve this problem, but rather to revisit the design choices of formal systems modelling distributed systems in attempt to evaluate their suitability for providing a formals basis for distributed program- ming languages. Our intention is to have a minimal process calculus which would be amenable to static analysis. More precisely, we wish to harmonize the assumptions of π-calculus with a linear typing discipline for process calculi called Session Types. -
FAQ on Pi-Calculus
FAQ on π-Calculus Jeannette M. Wing Visiting Researcher, Microsoft Research Professor of Computer Science, Carnegie Mellon University 27 December 2002 1. What is π-calculus? π -calculus is a model of computation for concurrent systems. The syntax of π-calculus lets you represent processes, parallel composition of processes, synchronous communication between processes through channels, creation of fresh channels, replication of processes, and nondeterminism. That’s it! 2. What do you mean by process? By channel? A process is an abstraction of an independent thread of control. A channel is an abstraction of the communication link between two processes. Processes interact with each other by sending and receiving messages over channels. 3. Could you be a little more concrete? Let P and Q denote processes. Then • P | Q denotes a process composed of P and Q running in parallel. • a(x).P denotes a process that waits to read a value x from the channel a and then, having received it, behaves like P. • ā〈x〉.P denotes a process that first waits to send the value x along the channel a and then, after x has been accepted by some input process, behaves like P. • (νa)P ensures that a is a fresh channel in P. (Read the Greek letter “nu” as “new.”) • !P denotes an infinite number of copies of P, all running in parallel. • P + Q denotes a process that behaves like either P or Q. • 0 denotes the inert process that does nothing. All concurrent behavior that you can imagine would have to be written in terms of just the above constructs. -
Experiences with the PEPA Performance Modelling Tools
Edinburgh Research Explorer Experiences with the PEPA performance modelling tools Citation for published version: Clark, G, Gilmore, S, Hillston, J & Thomas, N 1999, 'Experiences with the PEPA performance modelling tools', IEE Proceedings - Software, vol. 146, no. 1, pp. 11-19. https://doi.org/10.1049/ip-sen:19990149 Digital Object Identifier (DOI): 10.1049/ip-sen:19990149 Link: Link to publication record in Edinburgh Research Explorer Document Version: Peer reviewed version Published In: IEE Proceedings - Software General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 29. Sep. 2021 Experiences with the PEPA Performance Modelling Tools Graham Clark Stephen Gilmore Jane Hillston Nigel Thomas Abstract The PEPA language [1] is supported by a suite of modelling tools which assist in the solution and analysis of PEPA models. The design and development of these tools have been influenced by a variety of factors, including the wishes of other users of the tools to use the language for purposes which were not anticipated by the tool designers. In consequence, the suite of PEPA tools has adapted to attempt to serve the needs of these users while continuing to support the language designers themselves. -
Review of the Π-Calculus: a Theory of Mobile Processes∗
Review of The π-calculus: A Theory of Mobile Processes∗ Riccardo Pucella Department of Computer Science Cornell University July 8, 2001 Introduction With the rise of computer networks in the past decades, the spread of distributed applications with components across multiple machines, and with new notions such as mobile code, there has been a need for formal methods to model and reason about concurrency and mobility. The study of sequential computations has been based on notions such as Turing machines, recursive functions, the λ-calculus, all equivalent formalisms capturing the essence of sequential computations. Unfortunately, for concurrent programs, theories for sequential computation are not enough. Many programs are not simply programs that compute a result and return it to the user, but rather interact with other programs, and even move from machine to machine. Process calculi are an attempt at getting a formal foundation based on such ideas. They emerged from the work of Hoare [4] and Milner [6] on models of concurrency. These calculi are meant to model systems made up of processes communicating by exchanging values across channels. They allow for the dynamic creation and removal of processes, allowing the modelling of dynamic systems. A typical process calculus in that vein is CCS [6, 7]. The π-calculus extends CCS with the ability to create and remove communication links between processes, a new form of dynamic behaviour. By allowing links to be created and deleted, it is possible to model a form of mobility, by identifying the position of a process by its communication links. This book, “The π-calculus: A Theory of Mobile Processes”, by Davide Sangiorgi and David Walker, is a in-depth study of the properties of the π-calculus and its variants.