Self-Evaluation Applied Mathematics 2003-2008 University of Twente

This report contains the self-study for the research assessment of the Department of Applied Mathematics (AM) of the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) at the University of Twente (UT). The report provides the information for the Research Assessment Committee for Applied Mathematics, dealing with mathematical sciences at the three universities of technology in the Netherlands. It describes the state of affairs pertaining to the period 1 January 2003 to 31 December 2008

Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model

AI Solutions for MDS: Artificial Intelligence Techniques for Misuse Detection and Localisation in Telecommunication Environments

This report considers the application of Articial Intelligence (AI) techniques to the problem of misuse detection and misuse localisation within telecommunications environments. A broad survey of techniques is provided, that covers inter alia rule based systems, model-based systems, case based reasoning, pattern matching, clustering and feature extraction, articial neural networks, genetic algorithms, arti cial immune systems, agent based systems, data mining and a variety of hybrid approaches. The report then considers the central issue of event correlation, that is at the heart of many misuse detection and localisation systems. The notion of being able to infer misuse by the correlation of individual temporally distributed events within a multiple data stream environment is explored, and a range of techniques, covering model based approaches, `programmed' AI and machine learning paradigms. It is found that, in general, correlation is best achieved via rule based approaches, but that these suffer from a number of drawbacks, such as the difculty of developing and maintaining an appropriate knowledge base, and the lack of ability to generalise from known misuses to new unseen misuses. Two distinct approaches are evident. One attempts to encode knowledge of known misuses, typically within rules, and use this to screen events. This approach cannot generally detect misuses for which it has not been programmed, i.e. it is prone to issuing false negatives. The other attempts to `learn' the features of event patterns that constitute normal behaviour, and, by observing patterns that do not match expected behaviour, detect when a misuse has occurred. This approach is prone to issuing false positives, i.e. inferring misuse from innocent patterns of behaviour that the system was not trained to recognise. Contemporary approaches are seen to favour hybridisation, often combining detection or localisation mechanisms for both abnormal and normal behaviour, the former to capture known cases of misuse, the latter to capture unknown cases. In some systems, these mechanisms even work together to update each other to increase detection rates and lower false positive rates. It is concluded that hybridisation offers the most promising future direction, but that a rule or state based component is likely to remain, being the most natural approach to the correlation of complex events. The challenge, then, is to mitigate the weaknesses of canonical programmed systems such that learning, generalisation and adaptation are more readily facilitated

The Sketch of a Polymorphic Symphony

In previous work, we have introduced functional strategies, that is, first-class generic functions that can traverse into terms of any type while mixing uniform and type-specific behaviour. In the present paper, we give a detailed description of one particular Haskell-based model of functional strategies. This model is characterised as follows. Firstly, we employ first-class polymorphism as a form of second-order polymorphism as for the mere types of functional strategies. Secondly, we use an encoding scheme of run-time type case for mixing uniform and type-specific behaviour. Thirdly, we base all traversal on a fundamental combinator for folding over constructor applications. Using this model, we capture common strategic traversal schemes in a highly parameterised style. We study two original forms of parameterisation. Firstly, we design parameters for the specific control-flow, data-flow and traversal characteristics of more concrete traversal schemes. Secondly, we use overloading to postpone commitment to a specific type scheme of traversal. The resulting portfolio of traversal schemes can be regarded as a challenging benchmark for setups for typed generic programming. The way we develop the model and the suite of traversal schemes, it becomes clear that parameterised + typed strategic programming is best viewed as a potent combination of certain bits of parametric, intensional, polytypic, and ad-hoc polymorphism

Tackling the Awkward Squad for Reactive Programming: The Actor-Reactor Model

Reactive programming is a programming paradigm whereby programs are internally represented by a dependency graph, which is used to automatically (re)compute parts of a program whenever its input changes. In practice reactive programming can only be used for some parts of an application: a reactive program is usually embedded in an application that is still written in ordinary imperative languages such as JavaScript or Scala. In this paper we investigate this embedding and we distill "the awkward squad for reactive programming" as 3 concerns that are essential for real-world software development, but that do not fit within reactive programming. They are related to long lasting computations, side-effects, and the coordination between imperative and reactive code. To solve these issues we design a new programming model called the Actor-Reactor Model in which programs are split up in a number of actors and reactors. Actors and reactors enforce a strict separation of imperative and reactive code, and they can be composed via a number of composition operators that make use of data streams. We demonstrate the model via our own implementation in a language called Stella

Bridging the Gap between a Behavioural Formal Description Technique and User Interface description language: Enhancing ICO with a Graphical User Interface markup language

International audienceIn the last years, User Interface Description Languages (UIDLs) appeared as a suitable solution for developing interactive systems. In order to implement reliable and efficient applications, we propose to employ a formal description technique called ICO (Interactive Cooperative Object) that has been developed to cope with complex behaviours of interactive systems including event-based and multimodal interactions. So far, ICO is able to describe most of the parts of an interactive system, from functional core concerns to fine grain interaction techniques, but, even if it addresses parts of the rendering, it still not has means to describe the effective rendering of such interactive system. This paper presents a solution to overcome this gap using markup languages. A first technique is based on the Java technology called JavaFX and a second technique is based on the emergent UsiXML language for describing user interface components for multi-target platforms. The proposed approach offers a bridge between markup language based descriptions of the user interface components and a robust technique for describing behaviour using ICO modelling. Furthermore, this paper highlights how it is possible to take advantage from both behavioural and markup language description techniques to propose a new model-based approach for prototyping interactive systems. The proposed approach is fully illustrated by a case study using an interactive application embedded into interactive aircraft cockpits

Mobile Game-Based Learning (mGBL) Engineering Model

Mobile game-based learning (mGBL) is a game played on any handheld devices such as mobile phones. It is among the most recent growing research areas whereby its main aim is to use game play to enhance motivation in learning, engage in knowledge acquisition, and improve the effectiveness of learning activities through mobile environment. To fully utilize the potential of mGBL, researchers suggest looking at the most important part, which is the development methodology of mGBL. In relation to this, various game development methodologies have been introduced for different types of game genres and platforms. These methodologies propose different numbers of steps and activities; some focusing only on the learning design; some concentrating on the mobile technologies; and others on the complete life cycle. Although many game methodologies have been introduced, studies show that customized phases and steps to develop games for learning in mobile environment are substantially required. Therefore, the study discussed in this thesis addresses this gap by proposing an mGBL Engineering Model based on a number of games and learning theoretical and developmental foundations. In particular, the study identified the key steps of development methodology to be considered in developing mGBL applications which consist of phases, components, steps, and deliverables. In accomplishing this aim, a design science research methodology was adopted, comprising of five phases; (i) awareness of problem, (ii) suggestion, (iii) development, (iv) evaluation, and (v) conclusion. Subsequently, eight mGBL evaluation dimensions were put forward: visibility, complexity, compatibility, flexibility, clarity, effectiveness, manageability, and evolutionary. Model evaluation was conducted in three phases, namely; expert review, prototype development with heuristics evaluation, and experimental study. Generally, the proposed mGBL Engineering Model was well accepted by the experts contacted in this study. The model was also employed by a game company while developing an mGBL prototype. Here, the findings have implied that the model is useful to follow and it provides an easy guideline for fellow developers. In the experimental study phase, four learning or game methodologies; Analysis-Design-Development-Implementation- Evaluation, Input-Process-Output, Game Life Cycle, and mGBL Engineering Model; were studied and compared by 70 respondents. The findings have indicated that the proposed mGBL Engineering Model scored mean above 7.0 (out of 10) of all dimensions compared to the other three models (scored less than 7.0). The ANOVA results show that there are significant differences between all groups in six dimensions except complexity and compatibility. Although complexity and compatibility dimensions are not significantly different, the scores for the mGBL Engineering Model are higher than the other three models. All these results have demonstrated that the proposed mGBL Engineering Model exhibits useful development indicators for mGBL applications and is indeed a theoretical and practical contribution of the study. In addition, the other significant contributions are the eight evaluation dimensions together with the validated instrument. Furthermore, the artefact produced, which is the mGBL prototype is also a functional contribution

Medienkombinatorik für selektive Interface-Kulturen: Alternativen zu Paradigmen-geleiteten HCI-Entwicklungen

"Die langjährige Beschäftigung mit der Geschichte und Gegenwart von Interfaces und Interaktionsstilen von Informations- und Kommunikationstechniken in der Forschung und vor allem in der Lehre in der Elektrotechnik und Informatik vermittelte mir Einsichten, die die meist nur mit kurzen Zeithorizonten arbeitenden technisch-wissenschaftlichen Disziplinen nicht bieten. Die Langzeitperspektive ermöglicht konkretere Einblicke in die spezifische Entwicklungsdynamik von Bedienphilosophien und Bauweisen der Interfaces als die in der Human-Computer Interaction (HCI) stark verbreiteten schematischen Entwicklungsphasenmodelle. Denn die HCI ist eine von vielen Faktoren abhängige Gestaltungsdisziplin, die weder einem szientistischen Stufenkonzept folgt noch einer klar definierbaren technischen, ökonomischen, sozialen oder kulturellen Eigenlogik unterliegt. Betrachtet man dagegen Positionspapiere der HCICommunity auf Fachtagungen und theoretische Grundsatzartikel in den Fachzeitschriften über einen längeren Zeitraum, so zeigt sich sehr deutlich, dass Erweiterungen des Designraums der HCI regelmäßig zu Neuformulierungen von Entwicklungsgesetzen führen, die die neue modale Qualität als logischen nächsten Schritt oder gar Zielpunkt der Entwicklung deklarieren (vgl hierzu Hellige 2008b, Kap. 1). Ich werde dies in einem ersten Abschnitt anhand von früheren und aktuellen Beispielen demonstrieren und dabei zugleich in einem Zeitraffer den Wandel der Entwicklungsschwerpunkte der HCI skizzieren. Im zweiten Abschnitt möchte ich dann zeigen, dass Entwicklungsrichtungen in der HCI durchaus widersprüchlich sind, so dass von einer verbindlichen Entwicklungslogik nicht die Rede sein kann. Vielmehr mischen neue Interfaces und Medien den jeweiligen technischen Mix neu auf, sie setzen die bestehenden Interface- und Medienkulturen aber nicht außer Kraft. Im dritten Abschnitt wird anstelle des Denkens in Phasenmodellen und vorgegebenen Entwicklungsrichtungen eine medienkombinatorische Betrachtungsweise empfohlen und in Ansätzen vorgeführt. Der letzte Abschnitt stellt aufschlussreiche Beispiele von auf universellen HCI-Paradigmen basierenden und medienkombinatorisch angelegten Design-Konzepten gegenüber." (Autorenreferat