Arrows for knowledge-based circuits

Knowledge-based programs (KBPs) are a formalism for directly relating agents' knowledge and behaviour in a way that has proven useful for specifying distributed systems. Here we present a scheme for compiling KBPs to executable automata in finite environments with a proof of correctness in Isabelle/HOL. We use Arrows, a functional programming abstraction, to structure a prototype domain-specific synchronous language embedded in Haskell. By adapting our compilation scheme to use symbolic representations we can apply it to several examples of reasonable size

Constructive tool design for formal languages : from semantics to executing models

Embedded, distributed, real-time, electronic systems are becoming more and more dominant in our lives. Hidden in cars, televisions, mp3-players, mobile phones and other appliances, these hardware/software systems influence our daily activities. Their design can be a huge effort and has to be carried out by engineers in a limited amount of time. Computer-aided modelling and design automation shorten the design cycle of these systems enabling companies to deliver their products sooner than their competitors. The design process is divided into different levels of abstraction, starting with a vague product idea (abstract) and ending up with a concrete description ready for implementation. Recently, research has started to focus on the system level, being a promising new area at which the product design could start. This dissertation develops a constructive approach to building tools for system-level design/description/modelling/specification languages, and shows the applicability of this method to the system-level language POOSL (Parallel Object-Oriented Specification Language). The formal semantics of this language is redefined and partly redeveloped, adding probabilistic features, real-time, inheritance, concurrency within processes, dynamic ports and atomic (indivisible) expressions, making the language suitable for performance analysis/modelling. The semantics is two-layered, using a probabilistic denotational semantics for stating the meaning of POOSL’s data layer, and using a probabilistic structural operational semantics for the process layer and architecture layer. The constructive approach has yielded the system-level simulation tool rotalumis, capable of executing large industrial designs, which has been demonstrated by two successful case studies—an ATM-packet switch (in conjunction with IBM Research at Z¨urich) and a packet routing switch for the Internet (in association with Alcatel/Bell at Antwerp). The more generally applicable optimisations of the execution engine (rotalumis) and the decisions taken in its design are discussed in full detail. Prototyping, where the system-level model functions as a part of the prototype implementation of the designed product, is supported by rotalumis-rt, a real-time variant of the execution engine. The viability of prototyping is shown by a case study of a learning infrared remote control, partially realised in hardware and completed with a system-level model. Keywords formal languages / formal specification / modelling languages / systemlevel design / embedded systems / real-time systems / performance analysis / discrete event simulation / probabilistic process algebra / design automation / prototyping / simulation tool

Formal modelling and analysis of broadcasting embedded control systems

PhD ThesisEmbedded systems are real-time, communicating systems, and the effective modelling and analysis of these aspects of their behaviour is regarded as essential for acquiring confidence in their correct operation. In practice, it is important to minimise the burden of model construction and to automate the analysis, if possible. Among the most promising techniques for real-time systems are reachability analysis and model-checking of networks of timed automata. We identify two obstacles to the application of these techniques to a large class of distributed embedded systems: firstly, the language of timed automata is too low-level for straightforward model construction, and secondly, the synchronous, handshake communication mechanism of the timed automata model does not fit well with the asynchronous, broadcast mechanism employed in many distributed embedded systems. As a result, the task of model construction can be unduly onerous. This dissertation proposes an expressive language for the construction of models of real-time, broadcasting control systems, and demonstrates how effi- cient analysis techniques can be applied to them. The dissertation is concerned in particular with the Controller Area Network (CAN) protocol which is emerging as a de facto standard in the automotive industry. An abstract formal model of CAN is developed. This model is adopted as the communication primitive in a new language, bCANDLE, which includes value passing, broadcast communication, message priorities and explicit time. A high-level language, CANDLE, is introduced and its semantics defined by translation to bCANDLE. We show how realistic CAN systems can be described in CANDLE and how a timed transition model of a system can be extracted for analysis. Finally, it is shown how efficient methods of analysis, such as 'on-the- fly' and symbolic techniques, can be applied to these models. The dissertation contributes to the practical application of formal methods within the domain of broadcasting, embedded control systemsSchool of Computing and Mathematics at the University of Northumbri

Transparent synchronous dataflow: a functional paradigm for systems modelling and optimisation

System modelling is the use of mathematical formalisms to model real world systems for the purpose of analysis, simulation and prediction. One of the most common ways to model a system is to create the dataflow among its various components. There are two main approaches on how dataflow graphs are constructed in these system modelling frameworks: ‘define-and-run’ vs ‘define-by-run’. The former approach first creates a dataflow graph and then executes it by pushing data into it. The latter however constructs the graph while computing with data on-the-fly. ‘Define-and-run’ is usually more efficient because many graph optimisations can be applied; ‘Define-by-run’ however handles dynamic models better. This thesis aims to develop a new functional paradigm for systems modelling and optimisation that exhibits properties of both approaches where dataflow graphs are dynamic but efficient. We propose a new functional language, namely transparent synchronous dataflow (TSD), where dataflow graphs are constructed transparently with imperative commands to manipulate them explicitly; together with a synchronous mode of change propagation. The semantics of the language is designed on top of an unconventional graph abstract machine, Dynamic Geometry of Interaction Machine (DGoIM), which is natural for manipulating dataflow graphs. By using this semantics, the language is proved to be sound and efficient. Several experimental implementations were also created, including a native compiler for DGoIM and OCaml implementations for TSD

Actes des Sixièmes journées nationales du Groupement De Recherche CNRS du Génie de la Programmation et du Logiciel

National audienceCe document contient les actes des Sixièmes journées nationales du Groupement De Recherche CNRS du Génie de la Programmation et du Logiciel (GDR GPL) s'étant déroulées au CNAM à Paris du 11 au 13 juin 2014. Les contributions présentées dans ce document ont été sélectionnées par les différents groupes de travail du GDR. Il s'agit de résumés, de nouvelles versions, de posters et de démonstrations qui correspondent à des travaux qui ont déjà été validés par les comités de programmes d'autres conférences et revues et dont les droits appartiennent exclusivement à leurs auteurs

Transparent Synchronous Dataflow

Dataflow programming is a popular and convenient programming paradigm in systems modelling, optimisation, and machine learning. It has a number of advantages, for instance the lacks of control flow allows computation to be carried out in parallel as well as in distributed machines. More recently the idea of dataflow graphs has also been brought into the design of various deep learning frameworks. They facilitate an easy and efficient implementation of automatic differentiation, which is the heart of modern deep learning paradigm. [abstract abridged

Programming Languages and Systems

This open access book constitutes the proceedings of the 29th European Symposium on Programming, ESOP 2020, which was planned to take place in Dublin, Ireland, in April 2020, as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The actual ETAPS 2020 meeting was postponed due to the Corona pandemic. The papers deal with fundamental issues in the specification, design, analysis, and implementation of programming languages and systems

28th International Symposium on Temporal Representation and Reasoning (TIME 2021)

The 28th International Symposium on Temporal Representation and Reasoning (TIME 2021) was planned to take place in Klagenfurt, Austria, but had to move to an online conference due to the insecurities and restrictions caused by the pandemic. Since its frst edition in 1994, TIME Symposium is quite unique in the panorama of the scientifc conferences as its main goal is to bring together researchers from distinct research areas involving the management and representation of temporal data as well as the reasoning about temporal aspects of information. Moreover, TIME Symposium aims to bridge theoretical and applied research, as well as to serve as an interdisciplinary forum for exchange among researchers from the areas of artifcial intelligence, database management, logic and verifcation, and beyond