14,262 research outputs found
A CSP-Based Trajectory for Designing Formally Verified Embedded Control Software
This paper presents in a nutshell a procedure for producing formally verified concurrent software. The design paradigm provides means for translating block-diagrammed models of systems from various problem domains in a graphical notation for process-oriented architectures. Briefly presented CASE tool allows code generation both for formal analysis of the models of software and code generation in a target implementation language. For formal analysis a highquality commercial formal checker is used
The complexity of asynchronous model based testing
This is the post-print version of the final paper published in Theoretical Computer Science. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.In model based testing (MBT), testing is based on a model MM that typically is expressed using a state-based language such as an input output transition system (IOTS). Most approaches to MBT assume that communications between the system under test (SUT) and its environment are synchronous. However, many systems interact with their environment through asynchronous channels and the presence of such channels changes the nature of testing. In this paper we investigate the situation in which the SUT interacts with its environment through asynchronous channels and the problems of producing test cases to reach a state, execute a transition, or to distinguish two states. In addition, we investigate the Oracle Problem. All four problems are explored for both FIFO and non-FIFO channels. It is known that the Oracle Problem can be solved in polynomial time for FIFO channels but we also show that the three test case generation problems can also be solved in polynomial time in the case where the IOTS is observable but the general test generation problems are EXPTIME-hard. For non-FIFO channels we prove that all of the test case generation problems are EXPTIME-hard and the Oracle Problem in NP-hard, even if we restrict attention to deterministic IOTSs
Modeling and Testing Implementations of Protocols with Complex Messages
This paper presents a new language called APSL for formally describing
protocols to facilitate automated testing. Many real world communication
protocols exchange messages whose structures are not trivial, e.g. they may
consist of multiple and nested fields, some could be optional, and some may
have values that depend on other fields. To properly test implementations of
such a protocol, it is not sufficient to only explore different orders of
sending and receiving messages. We also need to investigate if the
implementation indeed produces correctly formatted messages, and if it responds
correctly when it receives different variations of every message type. APSL's
main contribution is its sublanguage that is expressive enough to describe
complex message formats, both text-based and binary. As an example, this paper
also presents a case study where APSL is used to model and test a subset of
Courier IMAP email server
International White Book on DER Protection : Review and Testing Procedures
This white book provides an insight into the issues surrounding the impact of increasing levels of DER on the generator and network protection and the resulting necessary improvements in protection testing practices. Particular focus is placed on ever increasing inverter-interfaced DER installations and the challenges of utility network integration. This white book should also serve as a starting point for specifying DER protection testing requirements and procedures. A comprehensive review of international DER protection practices, standards and recommendations is presented. This is accompanied by the identifi cation of the main performance challenges related to these protection schemes under varied network operational conditions and the nature of DER generator and interface technologies. Emphasis is placed on the importance of dynamic testing that can only be delivered through laboratory-based platforms such as real-time simulators, integrated substation automation infrastructure and fl exible, inverter-equipped testing microgrids. To this end, the combination of fl exible network operation and new DER technologies underlines the importance of utilising the laboratory testing facilities available within the DERlab Network of Excellence. This not only informs the shaping of new protection testing and network integration practices by end users but also enables the process of de-risking new DER protection technologies. In order to support the issues discussed in the white paper, a comparative case study between UK and German DER protection and scheme testing practices is presented. This also highlights the level of complexity associated with standardisation and approval mechanisms adopted by different countries
Embedding accessibility and usability: considerations for e-learning research and development projects
This paper makes the case that if e‐learning research and development projects are to be successfully adopted in real‐world teaching and learning contexts, then they must effectively address accessibility and usability issues; and that these need to be integrated throughout the project. As such, accessibility and usability issues need to be made explicit in project documentation, along with allocation of appropriate resources and time. We argue that accessibility and usability are intrinsically inter‐linked. An integrated accessibility and usability evaluation methodology that we have developed is presented and discussed. The paper draws on a series of mini‐case studies from e‐learning projects undertaken over the past 10 years at the Open University
Integrating DGSs and GATPs in an Adaptative and Collaborative Blended-Learning Web-Environment
The area of geometry with its very strong and appealing visual contents and
its also strong and appealing connection between the visual content and its
formal specification, is an area where computational tools can enhance, in a
significant way, the learning environments.
The dynamic geometry software systems (DGSs) can be used to explore the
visual contents of geometry. This already mature tools allows an easy
construction of geometric figures build from free objects and elementary
constructions. The geometric automated theorem provers (GATPs) allows formal
deductive reasoning about geometric constructions, extending the reasoning via
concrete instances in a given model to formal deductive reasoning in a
geometric theory.
An adaptative and collaborative blended-learning environment where the DGS
and GATP features could be fully explored would be, in our opinion a very rich
and challenging learning environment for teachers and students.
In this text we will describe the Web Geometry Laboratory a Web environment
incorporating a DGS and a repository of geometric problems, that can be used in
a synchronous and asynchronous fashion and with some adaptative and
collaborative features.
As future work we want to enhance the adaptative and collaborative aspects of
the environment and also to incorporate a GATP, constructing a dynamic and
individualised learning environment for geometry.Comment: In Proceedings THedu'11, arXiv:1202.453
COST Action IC 1402 ArVI: Runtime Verification Beyond Monitoring -- Activity Report of Working Group 1
This report presents the activities of the first working group of the COST
Action ArVI, Runtime Verification beyond Monitoring. The report aims to provide
an overview of some of the major core aspects involved in Runtime Verification.
Runtime Verification is the field of research dedicated to the analysis of
system executions. It is often seen as a discipline that studies how a system
run satisfies or violates correctness properties. The report exposes a taxonomy
of Runtime Verification (RV) presenting the terminology involved with the main
concepts of the field. The report also develops the concept of instrumentation,
the various ways to instrument systems, and the fundamental role of
instrumentation in designing an RV framework. We also discuss how RV interplays
with other verification techniques such as model-checking, deductive
verification, model learning, testing, and runtime assertion checking. Finally,
we propose challenges in monitoring quantitative and statistical data beyond
detecting property violation
Incremental verification of co-observability in discrete-event systems
Existing strategies for verifying co-observability, one of the properties that must be satisfied for synthesizing solutions to decentralized supervisory control problems, require the construction of the complete system model. When the system is composed of many subsystems, these monolithic approaches may be impractical due to the state-space explosion problem. To address this issue, we introduce an incremental verification of co-observability approach. Selected subgroups of the system are evaluated individually, until verification of co-observability is complete. The new method is potentially much more efficient than the monolithic approaches, in particular for systems composed of many subsystems, allowing for some intractable state-space explosion problems to be manageable. Properties of this new strategy are presented, along with a corresponding algorithm and an example
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Using formal methods to support testing
Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent
years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing
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