High assurance interactive computing systems

If interactive computing systems development is to be considered an engineering discipline, we need methods and tools to help us reason about and predict the quality of systems, from early in the design process. This paper provides a brief overview of work we have been carrying out in the general area of evaluating and ensuring the quality of interactive computing. systems. Some of the work currently being carried out is also discussed. Discussed approaches range from the formal verification of user interface models through model checking, to the reverse engineering and model based testing of implemented interactive computing systems

A critical review on modelling formalisms and simulation tools in computational biosystems

Integration of different kinds of biological processes is an ultimate goal for whole-cell modelling. We briefly review modelling formalisms that have been used in Systems Biology and identify the criteria that must be addressed by an integrating framework capable of modelling, analysing and simulating different biological networks. Aware that no formalism can fit all purposes we realize Petri nets as a suitable model for Metabolic Engineering and take a deeper perspective on the role of this formalism as an integrating framework for regulatory and metabolic networks.Research supported by PhD grant SFRH/BD/35215/2007 from the Fundacao para a Ciencia e a Tecnologia (FCT) and the MIT-Portugal program

Vers un modèle de vérification de la couche logique d'entreprise dans une architecture à 3 couches: modèle CPN-ECA

International audienceThis paper proposes a model for building a flexible system, which accepts and verifies the change on business logic, including both business processes and business rules, while the system has to cover the properties as reliability and reuse. In this model, the business process will be designed with Colour Petri Net and translated into a set of Event-Condition-Action rules, this set will be combined with business rules for checking the respect of a business process to the business rules in design and modifying the process. Hierarchical Colour Petri Net is also used to guarantee the reliability and to reuse properties of the system.Ce document propose un modèle pour la création d'un système flexible, qui accepte et vérifie les modifications apportées à la logique métier, y compris les processus et les règles métier, tandis que le système doit couvrir les propriétés en termes de fiabilité et de réutilisation. Dans ce modèle, le processus de gestion sera conçu avec un réseau Pétri coloré et traduit en un ensemble de règles Event-Condition-Action (ECA). Cet ensemble sera combiné à des règles de gestion permettant de vérifier le respect du processus de gestion par modifier le processus. Un réseau Pétri coloré hiérarchisé est également utilisé pour garantir la fiabilité et pour réutiliser les propriétés du systèm

Colored Petri Net: Its application to Sucrose Biosynthesis Pathway in Plasmodium falciparum

Sucrose plays major role as macromolecule used in organisms including Plasmodium falciparum (P.f.) to generate glucose for energy production in the glycolysis pathway. A metabolic pathway is a series of chemical reactions, which goes through various intermediate compounds to transform input compounds into a product. In this work, we modelled a metabolic pathway in Plasmodium falciparum using Colored Petri Net Markup Language (CPNML). The model was used to examine the dynamic behavior of the sucrose biosynthesis pathway which shows the interactions between the metabolites and the reactions in the sucrose biosynthesis pathway of Plasmodium falciparum. We further analyzed the model for its structural and quantitative properties using Petri Net theory. Our model gives more insight to the structure of the pathway and helps to improve our understanding of the biological processes within this pathway.Keywords: Sucrose, Colored Petri Net, Plasmodium falciparu

On Secure Workflow Decentralisation on the Internet

Decentralised workflow management systems are a new research area, where most work to-date has focused on the system's overall architecture. As little attention has been given to the security aspects in such systems, we follow a security driven approach, and consider, from the perspective of available security building blocks, how security can be implemented and what new opportunities are presented when empowering the decentralised environment with modern distributed security protocols. Our research is motivated by a more general question of how to combine the positive enablers that email exchange enjoys, with the general benefits of workflow systems, and more specifically with the benefits that can be introduced in a decentralised environment. This aims to equip email users with a set of tools to manage the semantics of a message exchange, contents, participants and their roles in the exchange in an environment that provides inherent assurances of security and privacy. This work is based on a survey of contemporary distributed security protocols, and considers how these protocols could be used in implementing a distributed workflow management system with decentralised control . We review a set of these protocols, focusing on the required message sequences in reviewing the protocols, and discuss how these security protocols provide the foundations for implementing core control-flow, data, and resource patterns in a distributed workflow environment

An infrastructure for experience centered agile prototyping of ambient intelligence

Ubiquitous computing poses new usability challenges that cut across design and development. We are particularly interested in "spaces" enhanced with sensors, public displays and personal devices. How can prototypes be used to explore the user's mobility and interaction, both explicitly and implicitly, to access services within these environments? Because of the potential cost of development and design failure, the characteristics of such systems must be explored using early versions of the system that could disrupt if used in the target environment. Being able to evaluate these systems early in the process is crucial to their successful development. This paper reports on an effort to develop a framework for the rapid prototyping and analysis of ambient intelligence systems

Reliability assessment techniques for medical procedures

Healthcare aims to deliver good patient outcomes. However deviations in the application of medical procedures can result in failure to deliver reliable care, variation in patient results, waste of hospital resources and increase of risk to staff and patients. Venepuncture – the act of taking blood samples for laboratory tests – has been practised for centuries and is still one of the most common invasive procedures in healthcare. Each step of the procedure can affect the quality of the sample and is thus important for preventing rejection of blood specimens, patient and staff injury and even death. There is evidence that, despite published guidelines, there is wide variability in terms of the procedure, its duration and success rates. This variability can depend on numerous factors: material factors, such as equipment and tubes used during the drawing of blood, and staff factors, such as tourniquet technique and skill of the individual. If the variability effects on outcomes can be evaluated in terms of process reliability and efficiency, potential changes to the current medical practice can be tested before they are proposed and implemented. In this paper a reliability assessment technique based on engineering reliability modelling methods is proposed. A technique based on Petri nets and simulation is presented which can be used to mimic and analyse the performance of a medical procedure through graphical and probabilistic modelling features. The technique can be used to demonstrate variations in the venepuncture procedure affect the outcomes, such as reliability and the duration of the procedure. Different scenarios of resource allocation can be analysed and the most critical steps of the procedure identified. The proposed technique is illustrated using the information gained from interview and questionnaire responses from doctors and phlebotomists working in UK hospitals

Vers un modèle de vérification de la couche logique d'entreprise dans une architecture à 3 couches: modèle CPN-ECA

International audienceThis paper proposes a model for building a flexible system, which accepts and verifies the change on business logic, including both business processes and business rules, while the system has to cover the properties as reliability and reuse. In this model, the business process will be designed with Colour Petri Net and translated into a set of Event-Condition-Action rules, this set will be combined with business rules for checking the respect of a business process to the business rules in design and modifying the process. Hierarchical Colour Petri Net is also used to guarantee the reliability and to reuse properties of the system.Ce document propose un modèle pour la création d'un système flexible, qui accepte et vérifie les modifications apportées à la logique métier, y compris les processus et les règles métier, tandis que le système doit couvrir les propriétés en termes de fiabilité et de réutilisation. Dans ce modèle, le processus de gestion sera conçu avec un réseau Pétri coloré et traduit en un ensemble de règles Event-Condition-Action (ECA). Cet ensemble sera combiné à des règles de gestion permettant de vérifier le respect du processus de gestion par modifier le processus. Un réseau Pétri coloré hiérarchisé est également utilisé pour garantir la fiabilité et pour réutiliser les propriétés du systèm

CPN Modelling And Performance Analysis Of CBHSA

Security is a major issue associated with MAs and Hosts. MAs themselves may need to be protected from the hosts they visit and vice versa. For mobile multi agents, a new Cryptography Based Hierarchical Security Architecture (CBHSA) has already been proposed in our previous work. CBHSA provides four different kinds of algorithms to secure agents during migration which combines various existing security mechanisms such as encryption and decryption, signed agreement etc. This paper gives the description of Colored Petri Net (CPN) modelling of CBHSA and analyses the performance of CBHSA against some identified parameters. Different graphs have been developed for min, max and average values of different parameters. Simulation results show that CBHSA gives expected result and secure MAs and hosts from attacks