Representational reasoning and verification

Formal approaches to the design of interactive systems, such as the principled design approach rely on reasoning about properties of the system at a very high level of abstraction. Such specifications typically provide little scope for reasoning about presentations and the representation of information in the presentation. Theories of distributed cognition place a strong emphasis on the role of representations in the cognitive process, but it is not clear how such theories can be applied to design. In this paper we show how a formalisation can be used to encapsulate representational aspects, affording us an opportunity to integrate representational reasoning into the design process. We have shown in [3] how properties over the abstract state place requirements on the presentation if the properties are to be valid at the perceptual level, and we have presented a model for such properties. We base our approach on this model, and examine in more detail the issue of verification. Given the widespread consensus that proper tool support is a prerequisite for the adoption of formal techniques, we apply a higher-order logic theorem prover to the analysis

Modelling and systematic analysis of interactive systems

Two aspects of our research concern the application of formal methods in human-computer interaction. The first aspect is the modelling and analysis of interactive devices with a particular emphasis on the user device dyad. The second is the modelling and analysis of ubiquitous systems where there are many users, one might say crowds of users.The common thread of both is to articulate and prove properties of interactive systems, to explore interactive behaviour as it influences the user, with a particular emphasis on interaction failure. The goal is to develop systematic techniques that can be packaged in such a way that they can be used effectively by developers. This “whitepaper” will briefly describe the two approaches and their potential value as well as their limitations and development opportunities

Considering context and users in interactive systems analysis

Although the take-up of formal approaches to modelling and reasoning about software has been slow, there has been recent interest and facility in the use of automated reasoning techniques such as model checking [5] on increasingly complex systems. In the case of interactive systems, formal methods can be particularly useful in reasoning about systems that involve complex interactions. These techniques for the analysis of interactive systems typically focus on the device and leave the context of use undocumented. In this paper we look at models that incorporate complexity explicitly, and discuss how they can be used in a formal setting. The paper is concerned particularly with the type of analysis that can be performed with them.This work was carried out in the context of the IVY project, supported by FCT (the Portuguese Foundation for Science and Technology) and FEDER (the European Regional Development Fund) under contract POSC/EIA/26646/2004

Uma abordagem formal à engenharia da usabilidade

A qualidade dos sistemas interactivos pode ser medida em termos da sua usabilidade. Abordagens empíricas à avaliação procuram avaliar os sistemas sob condições reais de utilização mas, tipicamente, são dispendiosos. Abordagens analíticas à análise de modelos tem sido propostas como um meio de raciocinar sobre questões de usabilidade desde as fases iniciais do desenvolvimento. Estas abordagens socorrem-se de modelos para focarem a análise em aspectos específicos da usabilidade. Neste contexto, a utilização de notações e ferramentas (matematicamente) formais tem sido proposta. Este artigo apresenta uma abordagem integrada à verificação de sistemas interactivos. A análise tanto pode ser realizada apenas tendo em conta o comportamento do artefacto, como permite a integração de um modelo de tarefas por forma a restringir o comportamento do artefacto a um subconjunto adequado de todos os seus possíveis comportamentos.The quality of an interactive system can be measured in terms of its usability. Empirical approaches to usability evaluation attempt to assess the system under real usage conditions. This type of approach can be very expensive. Analytical approaches have been proposed as a means of reasoning about usability issues from early in development. These approaches use models to focus the analysis in specific usuability issues. In this context, the aplication of (mathematically) formal notations and tools has been proposed.This paper presents a formal approach to the analysis of interactive systems. The analysis can be carried out taking into account all possible behaviours of the device, or it can be guided by the tasks the device is supposed to support

Specifying mobile network using a wp-like formal approach

The paper aims at providing a formal system, motivated by Dijkstra’s weakest precondition logic, for specifying mobile network. The paper shows how mobility can be specified using a state and transition based approach, which allows mobile hosts to be treated as nodes in a traditional statically structured distributed system. Another goal is to reason formally about the possible behaviors of a system consisting of mobile components. The handover procedure serves as an illustration for the notation. The contribution of the paper is the development of a style of modeling and reasoning about the temporal properties that allows for a straightforward and thorough analysis of mobile systems.Keywords: weakest precondition, mobile computing, specification, verification, safety, handover

Automated specification-based testing of graphical user interfaces

Tese de doutoramento. Engenharia Electrónica e de Computadores. 2006. Faculdade de Engenharia. Universidade do Porto, Departamento de Informática, Escola de Engenharia. Universidade do Minh

Integrating behavioural design into the virtual environment development process

A number of specifications formalisms have been developed (or applied) to support the abstract design of the behavioural component of the virtual environment interface. These formalisms subscribe to the philosophy that virtual environments should be viewed as hybrid systems which combine discrete and continuous behaviour. A significant deficiency in designing behaviour in this way is that the designs cannot be directly executed and explored in the same manner as an implementation. This limitation makes it di#cult for a designer to evaluate the suitability of designs. The thesis presents the Marigold toolset which supports two approaches to evaluating behaviour described using the Flownet hybrid formalism

Estudio teórico y evidencia empírica de la aplicación del marco teórico de "Cognición Distribuida" en la gestión de sistemas de formación e-Learning

Este trabajo de investigación se integra en el campo de estudio de la Interacción Humano Computadora (HCI) y del uso de las tecnologías de la información y la comunicación (TIC) en la educación.La investigación tiene como objetivo central explorar la aplicación del marco teórico de la "Cognición Distribuida" en la gestión de sistemas de formación en Internet, específicamente los que siguen una estrategia de e-learning.Una vez revisado el concepto de e-learning y explicada la necesidad de realizar investigaciones en este campo para mejorar el desarrollo del aprendizaje y la enseñanza, se procede a la revisión del estado teórico-tecnológico actual de la "Cognición Distribuida". Esta revisión facilita identificar los tópicos y aspectos de interés más estudiados en torno a esta teoría, las técnicas de investigación comúnmente relacionadas a su aplicación y los ámbitos en que ha sido aplicada, particularmente en el ámbito de la educación soportada por ordenador.La validez actual y a futuro de esta teoría se pone a reflexión mediante la realización de una encuesta aplicada a una muestra limitada de investigadores que la han empleado en distintos ámbitos.En paralelo a esta revisión, se procede a aplicar las ideas de la cognición distribuida en diversos sistemas de formación e-Learning con el objetivo de evaluar que tan bien esta teoría ayuda a identificar y explicar la naturaleza de los errores que surgen en el proceso de formación. Además, se esboza una idea inicial de cómo aplicar sus constructos de manera estructurada. Luego, se presenta el diseño de una infraestructura virtual (COLS) cuyo propósito es ayudar a mantener la base del aprendizaje, y por tanto la distribución de la cognición, en sistemas de actividad donde el conocimiento es su principal producto. El rendimiento parcial de algunos de sus componentes (un artefacto para realizar evaluaciones en tiempo real y un sistema hipermedia adaptativo) es presentado. Finalmente, sobre la base de los resultados obtenidos en todo el estudio, se valora la utilidad del marco teórico de "Cognición Distribuida" en la gestión de sistemas de formación, que siguen una estrategia de e-Learning.La presentación de la investigación se ha organizado en 4 capítulos:1. Objetivos y método de la investigación. Se definen los objetivos de la investigación, se delimita el ámbito para el cual tienen validez los resultados aportados y se expone el proceso de trabajo que se ha seguido.2. Estudio teórico.Se presentan los conocimientos que constituyen el marco de referencia y apoyo teórico de la investigación.3. Estudio empírico.Se presentan los diversos trabajos de campo que se han realizado y que constituyen el resultado final de esta investigación.4. Conclusiones.Se finaliza la presentación con una síntesis de las conclusiones a las que ha permitido llegar esta investigación exploratoria, así como las líneas de investigación futura derivadas de la misma.This research is included in the studies of the field of Human Computer Interaction (HCI) and the use of information technology and communication technologies (ICT) in education. The research aims to explore the application of the "Distributed Cognition" to the management of learning systems, specifically those which follow an e-learning strategy.Once the aspects of e-learning for review is done and the necessity of conducting research in this field to improve the development of learning and teaching is explained then the state of the art in the "Distributed Cognition" is presented. This work allows identifying the interested topics about this theory, the research techniques commonly related to its application and the areas where it has been studied, particularly in those supported by computer.The current and future validity of this theory is put to discussion by conducting a survey to collect information from a sample of researchers from different areas.While the theoretical study is developed, the distributed cognition is applied in two e-learning programs with the purpose to assess how well this theory helps to identify and explain the nature of the errors that arise in the learning process. In addition, it outlines an initial idea of how to implement its concepts in a structured manner. Then, the design of a virtual infrastructure ("COLS") is presented whose purpose is to help maintain the basis of learning in activity systems where the knowledge is their main product. The first results of the impact of some of its components (a device to perform real-time evaluations and an adaptive hypermedia system) are presented.Finally, on the basis of the results obtained throughout the research, we evaluate the usefulness of the "Distributed Cognition" in the management of learning systems which follow a e- learning strategy.The presentation of the research is organized into 4 chapters:1. Aims and research methodology.It defines the goals and research methodology, it narrows the scope for which results are valid provided and sets out the work process has been followed.2. Theoretical Study.Knowledge which constitutes the framework and theoretical support for this research are presented.3. Empirical Study.It presents the empirical works that have been developed. These empirical works constitute the final outcome of this research.4. Conclusions.This chapter presents an overview of the conclusions which this exploratory research has reached as well as future research works.Postprint (published version

Representational Reasoning and Verification

Formal approaches to the design of interactive systems rely on reasoning about properties of the system at a very high level of abstraction. Specifications to support such an approach typically provide little scope for reasoning about presentations and the representation of information in the presentation. In contrast, psychological theories such as distributed cognition place a strong emphasis on the role of representations, and their perception by the user, in the cognitive process. However, the post-hoc techniques for the observation and analysis of existing systems which have developed out of the theory do not help us in addressing such issues at the design stage. Mn this paper we show how a formalisation can be used to investigate the representational aspects of an interface. Our goal is to provide a framework to help identify and resolve potential problems with the representation of information, and to support understanding of representational issues in design. We present a model for linking properties at the abstract and perceptual levels, and illustrate its use in a case study of a ight deck instrument. There is a widespread consensus that proper tool support is a prerequisite for the adoption of formal techniques, but the use of such tools can have a profound effect on the process itself. In order to explore this issue, we apply a higher-order logic theorem prover to the analysis.Fundação para a Ciência e Tecnologia - PRAXIS XXI/BD/9562/96; European Union TMR Programme - TACIT network, contract ERB FMRX CT97 0133