Timed Automaton Models for Simple Programmable Logic Controllers

We give timed automaton models for a class of Programmable Logic Controller (PLC) applications, that are programmed in a simple fragment of the language Instruction Lists as defined in the standard IEC 1131-3. Two different approaches for modelling timers are suggested, that lead to two different timed automaton models. The purpose of this work is to provide a basis for verification and testing of real-time properties of PLC applications. Our work can be seen in broader context: it is a contribution to methodical development of provably correct programs. Even if the present PLC hardware will be substituted by e.g. Personal Computers, with a similar operation mode, the development and verification method will remain useful

Automated Verification of Quantum Protocols using MCMAS

We present a methodology for the automated verification of quantum protocols using MCMAS, a symbolic model checker for multi-agent systems The method is based on the logical framework developed by D'Hondt and Panangaden for investigating epistemic and temporal properties, built on the model for Distributed Measurement-based Quantum Computation (DMC), an extension of the Measurement Calculus to distributed quantum systems. We describe the translation map from DMC to interpreted systems, the typical formalism for reasoning about time and knowledge in multi-agent systems. Then, we introduce dmc2ispl, a compiler into the input language of the MCMAS model checker. We demonstrate the technique by verifying the Quantum Teleportation Protocol, and discuss the performance of the tool.Comment: In Proceedings QAPL 2012, arXiv:1207.055

An interval logic for higher-level temporal reasoning

Prior work explored temporal logics, based on classical modal logics, as a framework for specifying and reasoning about concurrent programs, distributed systems, and communications protocols, and reported on efforts using temporal reasoning primitives to express very high level abstract requirements that a program or system is to satisfy. Based on experience with those primitives, this report describes an Interval Logic that is more suitable for expressing such higher level temporal properties. The report provides a formal semantics for the Interval Logic, and several examples of its use. A description of decision procedures for the logic is also included

Correction by contrastive focus

'Correction' is the name of a sentence with contrastive focus' the phonological/phonetic realization of which is a single contrastive pitch accent. These sentences predominantly appear in (fictional) dialogues. The first speaker uses grammatical entities against which the next speaker protests with a sentence nearly identical except that it contains a prosodically marked corrective element. This paper makes contrastive focus visible by means of 'KF' (contrastive focus)

Modal Predicates

Despite the wide acceptance of standard modal logic, there has always been a temptation to think that ordinary modal discourse may be correctly analyzed and adequately represented in terms of predicates rather than in terms of operators. The aim of the formal model outlined in this paper is to capture what I take to be the only plausible sense in which ‘possible’ and ‘necessary’ can be treated as predicates. The model is built by enriching the language of standard modal logic with a quantificational apparatus that is “substitutional” rather than “objectual”, and by obtaining from the language so enriched another language in which constants for such predicates apply to singular terms that stand for propositions

Inter-modelling: From Theory to Practice

Proocedings of: ACM/IEEE 13 th International Conference on Model Driven Engineering Languages and Systems. Oslo, Norway, October 3-8, 2010.We define inter-modelling as the activity of building models that describe how modelling languages should be related. This includes many common activities in Model Driven Engineering, like the specification of model-to-model transformations, the definition of model matching and model traceability constraints, the development of inter-model consistency maintainers and exogenous model management operators. Recently, we proposed a formal approach to specify the allowed and forbidden relations between two modelling languages by means of bidirectional declarative patterns. Such specifications were used to generate graph rewriting rules able to enforce the relations in (forward and backward) model-to-model transformation scenarios. In this paper we extend the usage of patterns for two further inter-modelling scenarios &- model matching and model traceability &- and report on an EMF-based tool implementing them. The tool allows a high-level analysis of specifications based on the theory developed so far, as well as manipulation of traces by compilation of patterns into the Epsilon Object Language.Work funded by the Spanish Ministry of Science (project TIN2008-02081 and grants JC2009-00015, PR2009-0019), the R&D programme of the Madrid Region (project S2009/TIC-1650), the European Commission’s 7th Framework programme (grant #248864 (MADES)), and the Engineering and Physical Sciences Research Council (EPSRC) (grant EP/E034853/1).Publicad