Representing ASN.1 in Z

ASN.1 (Abstract Syntax Notation One) has been increasingly used in defining the data structures used in internet security protocols. In this paper we present a framework for translating ASN.1 specification into Z. We use a restricted version of ASN.1, which is however sufficiently powerful to specify important network communication protocols. Finally, we present an example of translation based on the Cryptographic Message Syntax of S/MIME

Learning and Activity Patterns in OSS Communities and their Impact on Software Quality

This paper presents a framework to identify and analyse learning and activity patterns that characterise participation and collaboration of individuals in Open Source Software (OSS) communities.  It first describes how participants’ activities enable and drive a learning process that occurs in individual participants as well as in the OSS project community as a whole. It then explores how to identify and analyse learning patterns at both individual level and community level. The objective of such analysis is to determine the impact of these patterns on the quality of the OSS product and define a descriptive approach to quality that is concerned less with standards than with the facts of OSS peer-review and peer-production

Closure and Attention Activation in Human Automatic Behaviour: A Framework for the Formal Analysis of Interactive Systems

Automatic behaviour can be defined as a fast processing human activity that does not require attention to occur. According to Norman and Shallice's model of attention and automaticity the majority of responses are under fairly automatic control triggered by environmental cues. In this paper we define a process algebraic framework to formalise Norman and Shallice's model and illustrate it through two case studies: Driving and using an Automatic Teller Machine (ATM). Finally we show how to use model-checking to analyse model instantiations and present the outcome of the analysis for the ATM case study

Using antipatterns to improve the quality of FLOSS development

Antipatterns have been mostly reported in closed source software environments. With the advent of Free/Libre Open Source Software (FLOSS), researchers have started analysing popular FLOSS projects, seeking vitality indicators and success patterns.  However, an impressively high percentage of FLOSS projects are unsuccessful.  Moreover, even in the successful cases of FLOSS there can be found tracks of failed attempts, dead-ends, forks, abandonments etc.  FLOSS antipatterns can help developers to improve their code and improve the communication and collaboration within the FLOSS community.  In this paper, we present some example of FLOSS antipatterns and discuss the benefits that they bring to various FLOSS user roles.  Furthermore, we present ontology-based technology and software tools that can be used to assist FLOSS developers and community users to identify, document, share antipatterns and use these mechanisms to assist FLOSS projects conform to specified requirements.  Finally, we propose a framework for the quantitative identification of the antipatterns to use as quality indicators in the certification of FLOSS products

Stochastic Modelling and Analysis of Driver Behaviour

Driver behaviour is considered a key factor in the majority of car accidents. As a consequence driver behaviour has been receiving vast attention in different domain areas, such as psychology, transport engineering and computer science. Computer scientists are primarily interested in what and how computing means can be applied to understand the relation between driver behaviour and transport systems. In this paper, we adopt a stochastic approach to conduct a quantitative investigation of driver behaviour. We use the Markovian process algebra PEPA (Performance Evaluation Process Algebra) to describe the overall system model. The system component describing the topology and dynamic of the traffic is composed in parallel with the system component describing the driver state and its evolution due to experience. We illustrate our approach using a three-way junction as an example and present the numerical results of the system analysis

Modelling Cell Cycle using Different Levels of Representation

Understanding the behaviour of biological systems requires a complex setting of in vitro and in vivo experiments, which attracts high costs in terms of time and resources. The use of mathematical models allows researchers to perform computerised simulations of biological systems, which are called in silico experiments, to attain important insights and predictions about the system behaviour with a considerably lower cost. Computer visualisation is an important part of this approach, since it provides a realistic representation of the system behaviour. We define a formal methodology to model biological systems using different levels of representation: a purely formal representation, which we call molecular level, models the biochemical dynamics of the system; visualisation-oriented representations, which we call visual levels, provide views of the biological system at a higher level of organisation and are equipped with the necessary spatial information to generate the appropriate visualisation. We choose Spatial CLS, a formal language belonging to the class of Calculi of Looping Sequences, as the formalism for modelling all representation levels. We illustrate our approach using the budding yeast cell cycle as a case study

Theoretical Aspects of Computing (ICTAC 2011)

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Integrating Data from Multiple Repositories to Analyze Patterns of Contribution in FOSS Projects

The majority of Free and Open Source Software (FOSS) developers are mobile and often use different identities in the projects or communities they participate in. These characteristics not only poses challenges for researchers studying the presence (where) and contributions (how much) of developers across multiple repositories, but may also require special attention when formulating appropriate metrics or indicators for the certification of both the FOSS product and process. In this paper, we present a methodology to study the patterns of contribution of 502 developers in both SVN and mailing lists in 20 GNOME projects. Our findings shows that only a small percentage of developers are contributing to both repositories and this cohort are making more commits than they are posting messages to mailing lists. The implications of these findings for our understanding of the patterns of contribution in FOSS projects and on the quality of the final product are discussed

Using Free/Libre Open Source Software Projects as E-learning Tools

Free/Libre Open Source Software (FLOSS) projects can be considered as learning environments in which heterogeneous communities get together to exchange knowledge through discussion and put it into practice through actual contributions to software development, revision and testing. This has encouraged tertiary educators to attempt the inclusion of participation in FLOSS projects as part of the requirements of Software Engineering courses, and pilot studies have been conducted to test the effectiveness of such an attempt. This paper discusses two pilot studies with reference to several studies concerning the role of learning in FLOSS projects and shows how using FLOSS projects as E-learning tools has a potential to increase the quality of the software product