Service-oriented Context-aware Framework

Location- and context-aware services are emerging technologies in mobile and desktop environments, however, most of them are difficult to use and do not seem to be beneficial enough. Our research focuses on designing and creating a service-oriented framework that helps location- and context-aware, client-service type application development and use. Location information is combined with other contexts such as the users' history, preferences and disabilities. The framework also handles the spatial model of the environment (e.g. map of a room or a building) as a context. The framework is built on a semantic backend where the ontologies are represented using the OWL description language. The use of ontologies enables the framework to run inference tasks and to easily adapt to new context types. The framework contains a compatibility layer for positioning devices, which hides the technical differences of positioning technologies and enables the combination of location data of various sources

Component Composition in Business and System Modelling

Bespoke development of large business systems can be couched in terms of the composition of components, which are, put simply, chunks of development work. Design, mapping a specification to an implementation, can also be expressed in terms of components: a refinement comprising an abstract component, a concrete component and a mapping between them. Similarly, system extension is the composition of an existing component, the legacy system, with a new component, the extension. This paper overviews work being done on a UK EPSRC funded research project formulating and formalizing techniques for describing, composing and performing integrity checks on components. Although the paper focuses on the specification and development of information systems, the techniques are equally applicable to the modeling and re-engineering of businesses, where no computer system may be involved

Multi-Device Design in Contexts of Interchange and Task Migration

Com a miniaturização dos componentes digitais e o vasto desenvolvimento tecnológico dos últimos anos, a sociedade tem presenciado a redefinição dos "computadores pessoais" pelo advento dos dispositivos móveis. Além da inovação, eles introduziram o desafio do design multi-dispositivo para as aplicações desktop. Enquanto algumas abordagens criaram interfaces móveis sem aproveitar qualquer modelo, outras buscaram adaptações automáticas visando reduzir a sobrecarga de designo Em ambas, o foco do design deixou de ser o usuário, tornando as interfaces tão diferentes ao ponto de comprometerem a usabilidade na realização de uma mesma tarefa em vários dispositivos. Esta tese afirma que não existe uma abordagem de design multi-dispositivo capaz de garantir boa usabilidade em todos os contextos porque o usuário pode escolher apenas uma forma de acesso à aplicação ou alternar seu uso por meio de vários dispositivos. No primeiro caso, o usuário aprende a usar a interface para realizar suas tarefas, sendo relevante uma abordagem que aproveite os recursos do dispositivo e trate suas limitações. No segundo, o usuário já conhece uma das interfaces, o que gera uma expectativa no uso das demais. Logo, é necessário combinar abordagens com objetivos diferentes para atender ao usuário de acordo com o seu contexto de uso. Neste sentido, propõe-se o design multi-dispositivo por meio da preservação de uma hierarquia de prioridades de consistência definida em três níveis. Enquanto os dois primeiros dão suporte à expectativa do usuário em contextos de uso alternado (propensos à execução de tarefas em dispositivos diferentes) e migração de tarefas (iniciando tarefas com um dispositivo e concluindo com outro), o terceiro nível garante a personalização das tarefas de maior interesse visando eficiência e satisfação de uso em um dispositivo específico. A avaliação desta metodologia foi feita por meio de um experimento com três interfaces de pocket PC construídas a partir de uma aplicação desktop do domínio de Educação a Distância: a primeira delas era uma réplica da original (Migração Direta), a segunda não mantinha consistência de layout e era baseada em um processo de design personalizado adequado ao dispositivo (Linear) e a terceira aplicava apenas os dois primeiros níveis da hierarquia de prioridades (Overview). Os resultados da avaliação subjetiva mostraram que a abordagem Overview foi capaz de manter o modelo mental do usuário com maior precisão por preservar os atributos de facilidade, eficiência e segurança de uso na interação inter-dispositivo. Além disso, os resultados medidos para a eficácia (exatidão das respostas) e eficiênciá (tempo médio de execução das tarefas) foram iguais ou melhores com essa abordagem. Por outro lado, os usuários revelaram uma preferência pela personalização de tarefas presente na abordagem Linear. Este resultado dá suporte à proposta desta tese, mostrando que a eficácia gerada pelos dois primeiros níveis da hierarquia de prioridades (percepção e execução das tarefas) deve ser combinada com o terceiro nível de personalização. Para isso, sugere-se a disponibilização de padrões de interface criados pelo designer para escolha do usuário durante a interação. Essa combinação deve garantir usabilidade no acesso a uma aplicação feito sempre por um mesmo dispositivo ou em contextos de uso alternado e migração de tarefasWith the miniaturization of digital components and the vast technological development of the past years, society has remarked the redefinition of "personal computers" by the advent of modern mobile devices. Besides the innovation, these handhelds also introduced the challenge to develop multi-device interfaces for today's desktop applications. While some created mobile interfaces from scratch to get the best from the devices, others looked for automatic adaptations to reduce the load imposed to the designeI. In both cases, the user wasn't the focus anymore, which resulted interfaces so different from each other to the point of compromising usability when peHorming one task on many devices. This thesis claims that there is no multi-device approach capable to provi de full usability in every context because the user may choose only one interface to access the application or interchange its use via many devices. In the first case, the user learns to perform tasks with the given device, which makes relevant an approach that takes advantage of its resources and solves its limitations. In the second, the user already knows one of the available interfaces, which generates an expectation for the others. Therefore, it is necessary to combine approaches with different goals and suit the user according to the appropriate context. In this sense, we propose multi-device design via maintenance of a consistency priorities hierarchy defined in three levels. The first two levels give support to the user's expectation in contexts of interchange (prone to task execution with different devices) and task migration (starting tasks with one device and finishing with other). On the other side, the third level provides task personalization according to the user's interest towards higher efficiency and satisfaction of use with a specific device. The evaluation of this methodology was conducted by an experiment with three pocket PC interfaces designed from an e-learning desktop application: the first interface was an exact replica of the original desktop version (Direct Migration), the second didn't maintain layout consistency and was based in a personalized design process adequate to the device (Linear) while the third applied only the first two levels of the consistency priorities hierarchy (Overview). The subjective evaluation results pointed the Overview approach as the best to maintain the user's mental model by preserving easiness, efficiency and safety of use on inter-device interaction. Additionally, both measured efficacy (task result accuracy) and efficiency (task execution mean time) were the same or even better with this approach. On the other hand, users revealed their preference for the task personalization present in the Linear approach. This result gives support to our proposal, corroborating that the efficacy generated by the first two levels of the consistency priorities hierarchy (task perception and execution) should be combined with the third level of personalization. This could be done by letting designers create interface patterns and make them available to users during interaction. Such combination should guarantee usability while constantly accessing one application through the same device or in contexts of alternated use and task migratio

The KB paradigm and its application to interactive configuration

The knowledge base paradigm aims to express domain knowledge in a rich formal language, and to use this domain knowledge as a knowledge base to solve various problems and tasks that arise in the domain by applying multiple forms of inference. As such, the paradigm applies a strict separation of concerns between information and problem solving. In this paper, we analyze the principles and feasibility of the knowledge base paradigm in the context of an important class of applications: interactive configuration problems. In interactive configuration problems, a configuration of interrelated objects under constraints is searched, where the system assists the user in reaching an intended configuration. It is widely recognized in industry that good software solutions for these problems are very difficult to develop. We investigate such problems from the perspective of the KB paradigm. We show that multiple functionalities in this domain can be achieved by applying different forms of logical inferences on a formal specification of the configuration domain. We report on a proof of concept of this approach in a real-life application with a banking company. To appear in Theory and Practice of Logic Programming (TPLP).Comment: To appear in Theory and Practice of Logic Programming (TPLP

Rewriting-based Verification and Debugging of Web Systems

The increasing complexity of Web system has led to the development of sophisticated formal methodologies for verifying and correcting Web data and Web programs. In general, establishing whether a Web system behaves correctly with respect to the original intention of the programmer or checking its internal consistency are non-trivial tasks as witnessed by many studies in the literature. In this dissertation, we face two challenging problems related to the verification of Web systems. Firstly, we extend a previous Web verification framework based on partial rewriting by providing a semi-automatic technique for repairing Web systems. We propose a basic repairing methodology that is endowed with several strategies for optimizing the number of repair actions that must be executed in order to fix a given Web site. Also, we develop an improvement of the Web verification framework that is based on abstract interpretation and greatly enhances both efficiency and scalability of the original technique. Secondly, we formalize a framework for the specification and model-checking of dynamic Web applications that is based on Rewriting Logic. Our framework allows one to simulate the user navigation and the evaluation of Web scripts within a Web application, and also check important related properties such us reachability and consistency. When a property is refuted, a counter-example with the erroneous trace is delivered. Such information can be analyzed in order to debug the Web application under examination by means of a novel backward trace slicing technique that we formulated for this purpose. This technique consists in tracing back, along an execution trace, all the relevant symbols of the term (or state) that we are interested to observe.Romero ., DO. (2011). Rewriting-based Verification and Debugging of Web Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/12496Palanci

Analyzing the Tagging Quality of the Spanish OpenStreetMap

In this paper, a framework for the assessment of the quality of OpenStreetMap is presented, comprising a batch of methods to analyze the quality of entity tagging. The approach uses Taginfo as a reference base and analyses quality measures such as completeness, compliance, consistence, granularity, richness and trust . The framework has been used to analyze the quality of OpenStreetMap in Spain, comparing the main cities of Spain. Also a comparison between Spain and some major European cities has been carried out. Additionally, a Web tool has been also developed in order to facilitate the same kind of analysis in any area of the world

Contracting the Facebook API

In recent years, there has been an explosive growth in the popularity of online social networks such as Facebook. In a new twist, third party developers are now able to create their own web applications which plug into Facebook and work with Facebook's "social" data, enabling the entire Facebook user base of more than 400 million active users to use such applications. These client applications can contain subtle errors that can be hard to debug if they misuse the Facebook API. In this paper we present an experience report on applying Microsoft's new code contract system for the .NET framework to the Facebook API.We wrote contracts for several classes in the Facebook API wrapper which allows Microsoft .NET developers to implement Facebook applications. We evaluated the usefulness of these contracts during implementation of a new Facebook application. Our experience indicates that having code contracts provides a better and quicker software development experience.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

Testing of xtUML Models across Auto-Reflexive Software Architecture

Application of MDA in the software development enables a synchronization of the system models and corresponding source files used for the building of the executable version of a software system. Because of often use of manual modifications of some parts of code without equivalent changes in connected models, there is no guarantee that the output of the process of building of the target application will be consistent with the relevant design and implementation models. Possibility of generating of the source files from the models is a necessity, but not a sufficient condition in the process of development and modification of software systems synchronously with the changes in all related models.  More safe approach is building the target application with the use of an automated building process with nested steps for consistency verifications of all critical models and related source files and the usage of model compilers. This article describes the method and tools for extending the software process of building the target system using special files with specification of dependencies between models and source files. Such dependencies represent the core of the critical knowledge, and it is possible to make this knowledge an integral part of the proposed new software architecture