Gourinath Banda

Techniques for scaling up analyses based on pre-interpretations

Any finite tree automaton (or regular type) can be used to construct an abstract interpretation of a logic program, by first determinising and completing the automaton to get a pre-interpretation of the language of the program. This has been shown to be a flexible and practical approach to building a variety of analyses, both generic (such as mode analysis) and program-specific (with respect to a type describing some particular property of interest). Previous work demonstrated the approach using pre-interpretations over small domains. In this paper we present techniques that allow the method to be applied to more complex pre-interpretations and larger programs. There are two main techniques presented: the first is a novel algorithm for determinising finite tree automata, yielding a compact “product” form of the transitions of the result automaton, that is often orders of magnitude smaller than an explicit representation of the automaton. Secondly, it is shown how this form (which is a representation of a pre-interpretation) can then be input directly to a BDD-based analyser of Datalog programs. We demonstrate through experiments that much more complex analyses become feasible.

Analysis of Linear Hybrid Systems in CLP

In this paper we present a procedure for representing the semantics of linear hybrid automata (LHAs) as constraint logic programs (CLP); flexible and accurate analysis and verification of LHAs can then be performed using generic CLP analysis and transformation tools. LHAs provide an expressive notation for specifying real-time systems. The main contributions are (i) a technique for capturing the reachable states of the continuously changing state variables of the LHA as CLP constraints; (ii) a way of representing events in the LHA as constraints in CLP, along with a product construction on the CLP representation including synchronisation on shared events; (iii) a framework in which various kinds of reasoning about an LHA can be flexibly performed by combining standard CLP transformation and analysis techniques. We give experimental results to support the usefulness of the approach and argue that we contribute to the general field of using static analysis tools for verification.

Constraint-based abstract semantics for temporal logic: a direct approach to design and implementation

Abstract interpretation provides a practical approach to verifying properties of infinite-state systems. We apply the framework of abstract interpretation to derive an abstract semantic function for the modal µ-calculus, which is the basis for abstract model checking. The abstract semantic function is constructed directly from the standard concrete semantics together with a Galois connection between the concrete state-space and an abstract domain. There is no need for mixed or modal transition systems to abstract arbitrary temporal properties, as in previous work in the area of abstract model checking. Using the modal µ-calculus to implement CTL, the abstract semantics gives an over-approximation of the set of states in which an arbitrary CTL formula holds. Then we show that this leads directly to an effective implementation of an abstract model checking algorithm for CTL using abstract domains based on linear constraints. The implementation of the abstract semantic function makes use of an SMT solver. We describe an implemented system for proving properties of linear hybrid automata and give some experimental results.

One IoT: an IoT protocol and framework for OEMs to make IoT-enabled devices forward compatible

Internet of Things (IoT) paradigm is going to imbue and become ubiquitous in everyday living, ranging from generic household, healthcare, public utility to defence applications. The IoT as a technology realm is witnessing advancement at a lightning speed. Consequently, there is a growing number of IoT-related reference architectures, frameworks, guidelines, platforms and standards. For IoT vendors and original equipment manufacturers (OEMs), however, such evolving IoT landscape means bountiful amounts of both opportunities and risks. The same holds for the consumers who are going to buy such products. We present an IoT framework and protocol that is unconditionally forward compatible. Our work defines the minimal criteria for a device to qualify as an IoT-enabled device, which could be taken as reference by IoT OEMs to build their IoT devices accordingly, across varied applications and domains. Such knowledge could help them make an informed choice amongst various available target hardware. With this protocol, it is possible to generate user interface/s on the fly, as per the devices’ functionalities.

An IoT Protocol and Framework for OEMs to Make IoT-Enabled Devices forward Compatible

Internet of Things (IoT) paradigm is going to imbue and become ubiquitous in everyday living, manufacturing and defense industries, health-care, etc. IoT as a technology realm is witnessing advancement at lightning speed. Consequently, there is a growing number of IoT-related reference architectures, frameworks, guidelines, platforms and standards. For IoT vendors and original equipment manufacturers (OEMs), however, such evolving IoT landscape means bountiful amounts of both opportunities and risks. The same holds for the consumers who are going to buy such products. We present an IoT framework and protocol that is unconditionally forward compatible. Our work defines the minimal criteria for a device to qualify asan IoT-enabled device, which could be taken as reference for IoT OEMs to build IoT-devices across varied applications and domains. Such knowledge could help them make an informed choice of corresponding hardware. The framework and protocol is both device and application independent, but still makes it possible to generate precise user interface/s on the fly.