Advanced SPIN Tutorial

Spin [9] is a model checker for the verification of distributed systems software. The tool is freely distributed, and often described as one of the most widely used verification systems. The Advanced Spin Tutorial is a sequel to [7] and is targeted towards intermediate to advanced Spin users

Scheduling Optimisations for SPIN to Minimise Buffer Requirements in Synchronous Data Flow

Synchronous Data flow (SDF) graphs have a simple and elegant semantics (essentially linear algebra) which makes SDF graphs eminently suitable as a vehicle for studying scheduling optimisations. We extend related work on using SPIN to experiment with scheduling optimisations aimed at minimising buffer requirements.We show that for a benchmark of commonly used case studies the performance of our SPIN based scheduler is comparable to that of state of the art research tools. The key to success is using the semantics of SDF to prove when using (even unsound and/or incomplete) optimisations are justified. The main benefit of our approach lies in gaining deep insight in the optimisations at relatively low cost

An Object-Oriented Framework for Explicit-State Model Checking

This paper presents a conceptual architecture for an object-oriented framework to support the development of formal verification tools (i.e. model checkers). The objective of the architecture is to support the reuse of algorithms and to encourage a modular design of tools. The conceptual framework is accompanied by a C++ implementation which provides reusable algorithms for the simulation and verification of explicit-state models as well as a model representation for simple models based on guard-based process descriptions. The framework has been successfully used to develop a model checker for a subset of PROMELA

Scheduling Optimisations for SPIN to Minimise Buffer Requirements in Synchronous Data Flow:(with appendix)

Synchronous Data flow (SDF) graphs have a simple and elegant semantics (essentially linear algebra) which makes SDF graphs eminently suitable as a vehicle for studying scheduling optimisations. We extend related work on using SPIN to experiment with scheduling optimisations aimed at minimising buffer requirements. We show that for a benchmark of commonly used case studies the performance of our SPIN based scheduler is comparable to that of state of the art research tools. The key to success is using the semantics of SDF to prove when using (even unsound and/or incomplete) optimisations are justified. The main benefit of our approach lies in gaining deep insight in the optimisations at relatively low cost

The bounded retransmission protocol must be on time!

This paper concerns the transfer of files via a lossy communication channel. It formally specifies this file transfer service in a property-oriented way and investigates -using two different techniques -whether a given bounded retransmission protocol conforms to this service. This protocol is based on the well-known alternating bit protocol but allows for a bounded number of retransmissions of a chunk, i.e., part of a file, only. So, eventual delivery is not guaranteed and the protocol may abort the file transfer. We investigate to what extent real-time aspects are important to guarantee the protocol's correctness and use Spin and Uppaal model checking for our purpose

Deciding to enter tertiary education and taking on debt : a longitudinal perspective

This thesis describes a program of research designed to investigate longitudinally the role of debt in a cohort of 1232 final-year New Zealand secondary school students, their tertiary entry decisions and their attitudes towards tertiary education and student debt. It follows some of these students into their first year out of school into tertiary education or otherwise. Two surveys were conducted that employed the Attitude to Debt Scale (Davies and Lea, 1995) to address students’ debt and savings behaviour and estimates, tertiary education entry decisions, and attitudes to tertiary education and term-time working. Debt attitudes are found to be more complex than previously proposed, and this has significant ramifications for debt attitude theory and research. Longitudinal comparisons suggest students’ views regarding debt necessity does not change but their attitude to avoiding does. Students become more or less avoidant of debt depending on their circumstances. However, debt attitude results still support many of the findings of earlier research such as debt acquisition preceding a more tolerant attitude change. Debt and tertiary education attitudes are not well predicted. Students report engaging in term-time working to limit their student loans, but engaging in term-time working results in lower grades in their studies. Those from the middle and higher socio-economic classes are more likely to be positive towards tertiary education, and thus entrants, compared with the lower socio-economic classes. However, the results do not suggest this is due to debt attitudes or fear of debt

Xspin/Project - Integrated Validation Management for Xspin

One of the difficulties of using model checkers “in the large” is the management of all (generated) data during the validation trajectory. It is important that the results obtained from the validation are always reproducible. Without tool support, the quality of the validation process depends on the accuracy of the persons who conduct the validation. This paper discusses , an extension of , which automatically controls and manages the validation trajectory when using the model checker