63,572 research outputs found
Towards Practical Graph-Based Verification for an Object-Oriented Concurrency Model
To harness the power of multi-core and distributed platforms, and to make the
development of concurrent software more accessible to software engineers,
different object-oriented concurrency models such as SCOOP have been proposed.
Despite the practical importance of analysing SCOOP programs, there are
currently no general verification approaches that operate directly on program
code without additional annotations. One reason for this is the multitude of
partially conflicting semantic formalisations for SCOOP (either in theory or
by-implementation). Here, we propose a simple graph transformation system (GTS)
based run-time semantics for SCOOP that grasps the most common features of all
known semantics of the language. This run-time model is implemented in the
state-of-the-art GTS tool GROOVE, which allows us to simulate, analyse, and
verify a subset of SCOOP programs with respect to deadlocks and other
behavioural properties. Besides proposing the first approach to verify SCOOP
programs by automatic translation to GTS, we also highlight our experiences of
applying GTS (and especially GROOVE) for specifying semantics in the form of a
run-time model, which should be transferable to GTS models for other concurrent
languages and libraries.Comment: In Proceedings GaM 2015, arXiv:1504.0244
Unfolding-based Partial Order Reduction
Partial order reduction (POR) and net unfoldings are two alternative methods
to tackle state-space explosion caused by concurrency. In this paper, we
propose the combination of both approaches in an effort to combine their
strengths. We first define, for an abstract execution model, unfolding
semantics parameterized over an arbitrary independence relation. Based on it,
our main contribution is a novel stateless POR algorithm that explores at most
one execution per Mazurkiewicz trace, and in general, can explore exponentially
fewer, thus achieving a form of super-optimality. Furthermore, our
unfolding-based POR copes with non-terminating executions and incorporates
state-caching. Over benchmarks with busy-waits, among others, our experiments
show a dramatic reduction in the number of executions when compared to a
state-of-the-art DPOR.Comment: Long version of a paper with the same title appeared on the
proceedings of CONCUR 201
Symbolic Partial-Order Execution for Testing Multi-Threaded Programs
We describe a technique for systematic testing of multi-threaded programs. We
combine Quasi-Optimal Partial-Order Reduction, a state-of-the-art technique
that tackles path explosion due to interleaving non-determinism, with symbolic
execution to handle data non-determinism. Our technique iteratively and
exhaustively finds all executions of the program. It represents program
executions using partial orders and finds the next execution using an
underlying unfolding semantics. We avoid the exploration of redundant program
traces using cutoff events. We implemented our technique as an extension of
KLEE and evaluated it on a set of large multi-threaded C programs. Our
experiments found several previously undiscovered bugs and undefined behaviors
in memcached and GNU sort, showing that the new method is capable of finding
bugs in industrial-size benchmarks.Comment: Extended version of a paper presented at CAV'2
Verification of Timed Automata Using Rewrite Rules and Strategies
ELAN is a powerful language and environment for specifying and prototyping
deduction systems in a language based on rewrite rules controlled by
strategies. Timed automata is a class of continuous real-time models of
reactive systems for which efficient model-checking algorithms have been
devised. In this paper, we show that these algorithms can very easily be
prototyped in the ELAN system. This paper argues through this example that
rewriting based systems relying on rules and strategies are a good framework to
prototype, study and test rather efficiently symbolic model-checking
algorithms, i.e. algorithms which involve combination of graph exploration
rules, deduction rules, constraint solving techniques and decision procedures
Model-based dependability analysis : state-of-the-art, challenges and future outlook
Abstract: Over the past two decades, the study of model-based dependability analysis has gathered significant research interest. Different approaches have been developed to automate and address various limitations of classical dependability techniques to contend with the increasing complexity and challenges of modern safety-critical system. Two leading paradigms have emerged, one which constructs predictive system failure models from component failure models compositionally using the topology of the system. The other utilizes design models - typically state automata - to explore system behaviour through fault injection. This paper reviews a number of prominent techniques under these two paradigms, and provides an insight into their working mechanism, applicability, strengths and challenges, as well as recent developments within these fields. We also discuss the emerging trends on integrated approaches and advanced analysis capabilities. Lastly, we outline the future outlook for model-based dependability analysis
Exploring the role of servitization to overcome barriers for innovative energy efficiency technologies – the case of public LED street lighting in German municipalities
In this paper we analyse the case for public application of LED street lighting. Drawing from the energy services literature and transaction cost economics, we compare modes of lighting governance for modernisation. We argue that servitization can accelerate the commercialisation and diffusion of end-use energy demand reduction (EUED) technologies in the public sector if third party energy service companies (ESCo) overcome technological, institutional and economic barriers that accompany the introduction of such technologies resulting in transaction costs. This can only succeed with a supportive policy framework and an environment conducive towards the dissemination of specific technological and commercial knowledge required for the diffusion process
- …