Discovery and Selection of Certified Web Services Through Registry-Based Testing and Verification

Reliability and trust are fundamental prerequisites for the establishment of functional relationships among peers in a Collaborative Networked Organisation (CNO), especially in the context of Virtual Enterprises where economic benefits can be directly at stake. This paper presents a novel approach towards effective service discovery and selection that is no longer based on informal, ambiguous and potentially unreliable service descriptions, but on formal specifications that can be used to verify and certify the actual Web service implementations. We propose the use of Stream X-machines (SXMs) as a powerful modelling formalism for constructing the behavioural specification of a Web service, for performing verification through the generation of exhaustive test cases, and for performing validation through animation or model checking during service selection

Computer-Aided Validation of Formal Conceptual Models

Conceptual modelling is the process of the software life cycle concerned with the identification and specification of requirements for the system to be built. The use of formal specification languages provides more precise and concise specifications. Nevertheless, there is still a need for techniques to support the validation of formal specifications against the informal user requirements. A limitation of formal specifications is that they cannot readily be understood by users unless they have been specially trained. However, user validation can be facilitated by exploiting the executable aspects of formal specification languages. This thesis presents a systematic approach and workbench environment to support the construction and validation through animation of TROLL specifications. Our approach is an iterative requirements definition process consisting of the formal specification of requirements, the automatic transformation of the specification into an executable form, and the interactive animation of the executable version to validate user requirements. To provide objects with persistence in the animation environment, we analyse how the static structure of TROLL objects can be mapped into relational tables. In order to execute the specification, we analyse the operational meaning of state transitions in TROLL, determine an execution model, and describe the transformation of the specifications into C++ code. We present a prototype implementation of the workbench environment.Die konzeptionelle Modellierung ist die Phase im Softwareentwurf, die sich mit der Identifikation und der Spezifikation von Systemanforderungen befasst. Formale Spezifikationssprachen ermöglichen präzisere und eindeutigere Spezifikationen. Trotzdem werden Techniken zur Validierung von formalen Spezifikationen bezüglich der informellen Benutzeranforderungen weiterhin benötigt. Ein Nachteil von formalen Spezifikationen ist, dass sie für Benutzer ohne entsprechende Vorkenntnisse nicht leicht verständlich sind. Die Einbeziehung der Benutzer in den Validierungsprozess kann jedoch durch die Ausführung der Spezifikation vereinfacht werden. Diese Arbeit liefert einen systematischen Ansatz und eine Entwicklungsumgebung für die Konstruktion von TROLL-Spezifikationen und deren Validierung durch Animation. Unser Ansatz basiert auf einem iterativen Prozess zur Anforderungsdefinition bestehend aus der formalen Spezifikation von Anforderungen, der automatischen Übersetzung der Spezifikation in eine ausführbare Form, und der interaktiven Animation um die Benutzeranforderungen zu validieren. Um die Objektzustände in der Animationsumgebung persistent zu halten, wird untersucht, wie die statische Struktur von TROLL-Objekten in relationale Tabellen umgesetzt werden kann. Um die Spezifikationen auszuführen, wird die operationale Bedeutung von TROLL-Zustandsübergängen analysiert und ein Ausführungsmodell festgelegt. Anschließend wird die Übersetzung von den Spezifikationen in C++ beschrieben. Wir zeigen eine prototypische Implementierung der Animationsumgebung

Representing and Parameterizing Agent Behaviors

The last few years have seen great maturation in understanding how to use computer graphics technology to portray 3D embodied characters or virtual humans. Unlike the off-line, animator-intensive methods used in the special effects industry, real-time embodied agents are expected to exist and interact with us live . They can be represent other people or function as autonomous helpers, teammates, or tutors enabling novel interactive educational and training applications. We should be able to interact and communicate with them through modalities we already use, such as language, facial expressions, and gesture. Various aspects and issues in real-time virtual humans will be discussed, including consistent parameterizations for gesture and facial actions using movement observation principles, and the representational basis for character believability, personality, and affect. We also describe a Parameterized Action Representation (PAR) that allows an agent to act, plan, and reason about its actions or actions of others. Besides embodying the semantics of human action, the PAR is designed for building future behaviors into autonomous agents and controlling the animation parameters that portray personality, mood, and affect in an embodied agent

Implementing Motivational Features for an Augmented Reality Game Encouraging Physical Activity for Persons with Intellectual Disabilities

Evidence shows lower physical activity (PA) levels in persons with an intellectual disability (ID) compared to the general population. Physical activity promotes multiple health benefits, such as prolonged life and reduced risk for obtaining various chronic diseases. There are numerous applications targeting increased physical activity for the general population, but these tend to be too complex to use, and have therefore not been adopted, by persons with ID. Exergames promote increased physical activity by utilizing the entertaining aspects of games as a motivator, and some research has been explicitly aimed toward providing such a platform for persons with ID. One application targeting increased PA levels in persons with ID is Sorterius. While Sorterius promotes PA during utilization, it is somewhat limited in providing motivational elements to its users, and an increase in motivational elements could greatly increase usage of the application. Therefore, the main goal of this project was to enhance the overall enjoyment of playing Sorterius. To reach this goal, the project utilized knowledge gained from a prior literature review assessing which game aspects persons with ID perceived as motivating. The project also relied on continuous discussion with experts in the field. The resulting design includes a customizable mascot where users can unlock new items for their mascot and an automated difficulty adjustment based on user performance. To evaluate the application, a usability test was conducted on two experts and six persons with ID for a duration of two weeks. Due to various reasons, we were only able to retrieve written consent from one of the persons with ID before submitting the thesis. Results from testing indicated a similar degree of usability as the previous version while providing an increased number of motivational elements towards its users. The new version was also tested on the intended users compared to the previous version

Creation of dynamic virtual tours in multimedia spaces

With the advancement of technology, it has become possible to carry out virtual tours to physical spaces, without being there in person. With the pandemic, this type of technology proved to be of great importance for places like museums due to people only leaving home to go to places of extreme importance, such as the hospital or to buy essential goods, but even that began to be less thanks to the existence of applications like Uber that deliver food at home. In case of physical tours, with the innovation of technology, it is possible to use augmented reality to make the visits more interesting and thus enrich the experience. Although virtual tours are useful, there are still certain difficulties in their implementation due to the inclusion of dynamic elements, such as interaction with people and the scenery. Throughout this paper, these same difficulties will be addressed and explained how they were resolved. Build2050 is a European project coordinated by IPS, which aims to build smart and sustainable buildings. This dissertation consists of the implementation of the technologies mentioned above, to provide different ways of visiting buildings and be more impactful for the visitor

Policy-based approach for context-aware systems

Pervasive (ubiquitous) computing is a new paradigm where the computers are submerged into the background of the everyday life. One important aspect of pervasive systems is context-awareness. Context-aware systems are those that can adapt their behaviours according to the current context. Context-aware applications are being integrated into our everyday activity aspects such as: health care, smart homes and transportations. There exist a wide range of context-aware applications such as: mobile phones, learning systems, smart vehicles. Some context-aware systems are critical since the consequence of failing to identify a given context may be catastrophic. For example, an auto-pilot system is a critical context-aware system; it senses the humidity, clouds, wind speed and accordingly adjusts the altitude, throttle and other parameters. Being a critical context-aware system has to be provably correct. Policy-based approaches has been used in many applications but not in context-aware systems. In this research, we want to discover the anatomy (i.e. architecture, structure and operational behaviour) of policy-based management as applied to context-aware systems, and how policies are managed within such a dynamic system. We propose a novel computational model and its formalisation is presented using the Calculus of Context-aware Ambients (CCA). CCA has been proposed as a suitable mathematical notation to model mobile and context-aware systems. We decided to use CCA due to three reasons: (i) in CCA, mobility and context-awareness are primitive constructs and are treated as first-class citizens; (ii) properties of a system can be formally analysed; (iii) CCA specifications are executable, and thus, leading to rapid prototyping and early validation of the system properties. We, then show how policies can be expressed in CCA. For illustration, the specification of the event-condition-action (ECA) conceptual policy model is modelled in CCA in a natural fashion. We also propose a policy-based architecture for context-aware systems, showing its different components, and how they interact. Furthermore, we give the specification of the policy enforcement mechanism used in our proposed architecture in CCA. To evaluate our approach, a real-world case study of an infostation-based mobile learning (mLearning) system is chosen. This mLearning system is deployed across a university campus to enable mobile users to access mobile services (mServices) represented by course materials (lectures, tests and tutorials) and communication services (intelligent message notification and VoIP). Users can access the mServices through their mobile devices (Hand-set phones, PDAs and laptops) regardless of their device type or location within a university campus. We have specified the mLearning system in CCA (i.e. specification based on policies of the mServices), afterwards, the specification is simulated using the CCA interpreter tool. We have developed an animation tool specially designed for the mLearning system. The animation tool provides graphical representation of the CCA processes. In terms of safety and liveness, some important properties of the mLearning system have been validated as a proof of concept

A language and toolkit for the specification, execution and monitoring of dependable distributed applications

PhD ThesisThis thesis addresses the problem of specifying the composition of distributed applications out of existing applications, possibly legacy ones. With the automation of business processes on the increase, more and more applications of this kind are being constructed. The resulting applications can be quite complex, usually long-lived and are executed in a heterogeneous environment. In a distributed environment, long-lived activities need support for fault tolerance and dynamic reconfiguration. Indeed, it is likely that the environment where they are run will change (nodes may fail, services may be moved elsewhere or withdrawn) during their execution and the specification will have to be modified. There is also a need for modularity, scalability and openness. However, most of the existing systems only consider part of these requirements. A new area of research, called workflow management has been trying to address these issues. This work first looks at what needs to be addressed to support the specification and execution of these new applications in a heterogeneous, distributed environment. A co- ordination language (scripting language) is developed that fulfils the requirements of specifying the composition and inter-dependencies of distributed applications with the properties of dynamic reconfiguration, fault tolerance, modularity, scalability and openness. The architecture of the overall workflow system and its implementation are then presented. The system has been implemented as a set of CORBA services and the execution environment is built using a transactional workflow management system. Next, the thesis describes the design of a toolkit to specify, execute and monitor distributed applications. The design of the co-ordination language and the toolkit represents the main contribution of the thesis.UK Engineering and Physical Sciences Research Council, CaberNet, Northern Telecom (Nortel)