2013, Grossniklaus, Michael, Leone, Stefania, Spindler, Alexandre de, Norrie, Moira C.

Databases play a key role in an increasingly diverse range of applications and settings. New requirements are continually emerging and may differ substantially from one domain to another, sometimes even to the point of conflict. To address these challenges, database systems are evolving to cater for new application domains. Yet little attention has been given to the process of researching and developing database concepts in response to new requirements. We present a platform designed to support database research in terms of experimentation with different aspects of database systems ranging from the data model to the distribution architecture. Our platform is based on the notion of metamodel extension modules, inspired by proposals for adaptive and configurable database management systems. However, rather than building a tailored system from existing components, we focus on the process of designing new components. To qualitatively evaluate our platform, we present a series of case studies where our approach was used successfully to experiment with concepts designed to support a variety of novel application domains.

2010, Grossniklaus, Michael, de Spindler, Alexandre, Zimmerli, Christoph, Norrie, Moira C.

In contrast to their relational counterparts, object databases are more heterogeneous in terms of their architecture, data model and functionality. To this day, this heterogeneity poses substantial difficulties when it comes to benchmark or interoperate object databases. While standardisation proposals have been made in the past, they have had limited impact as neither industry nor research has fully adopted them. We believe that one reason for this lack of adoption is that these standards were too restrictive and thus not capable of dealing with the heterogeneity of object databases. In this paper, we propose a uniform interface for access to object databases that is based on a flexible object model and algebra.

2010, Grossniklaus, Michael, Leone, Stefania, de Spindler, Alexandre, Norrie, Moira C.

Most object databases offer little or no support for event-based programming over and above what is provided in the programming language. Consequently, functionality offered by traditional database triggers and event-condition-action (ECA) rules has to be coded in each application. We believe that a notion of triggers should be offered by object databases to facilitate application development and a clear separation of concerns. We present a general and flexible event model that unifies concepts from programming languages and database triggers. We describe an implementation of the model and how it can support the requirements of a rich variety of applications.

2009, de Spindler, Alexandre, Grossniklaus, Michael, Lins, Christoph, Norrie, Moira C.

Current mobile phone technologies have fostered the emergence of a new generation of mobile applications. Such applications allow users to interact and share information opportunistically when their mobile devices are in physical proximity or close to fixed installations. It has been shown how mobile applications such as collaborative filtering and location-based services can take advantage of ad-hoc connectivity to use physical proximity as a filter mechanism inherent to the application logic. We discuss the different modes of information sharing that arise in such settings based on the models of persistence and synchronisation. We present a platform that supports the development of applications that can exploit these modes of ad-hoc information sharing and, by means of an example, show how such an application can be realised based on the supported event model.

2012, Nebeling, Michael, Speicher, Maximilian, Grossniklaus, Michael, Norrie, Moira C.

Many different automatic usability evaluation tools have been specifically developed for web sites and web-based services, but they usually cannot replace user testing. At the same time, traditional usability evaluation methods can be both expensive and time consuming. We will demonstrate CrowdStudy, a toolkit for crowdsourced testing of web interfaces that allows, not only to efficiently recruit larger amounts of test users, but also to evaluate web sites under many different conditions.

2010, Grossniklaus, Michael, Leone, Stefania, de Spindler, Alexandre, Norrie, Moira C.

Databases are now used in a wide variety of settings resulting in requirements which may differ substantially from one application to another, even to the point of conflict. Consequently, there is no database product that can support all forms of information systems ranging from enterprise applications to personal information systems running on mobile devices. Further, domains such as the Web have demonstrated the need to cope with rapidly evolving requirements. We define dynamic metamodel extension modules that support adaptive data management by evolving a system in the event of changing requirements and show how this technique was applied to cater for specific application settings.

2010, Norrie, Moira C., Grossniklaus, Michael

2012, Nebeling, Michael, Grossniklaus, Michael, Leone, Stefania, Norrie, Moira C.

There is a vast body of research dealing with the development of context-aware web applications that can adapt to different user, platform and device contexts. However, the range and growing diversity of new devices poses two significant problems to existing approaches. First, many techniques require a number of additional design processes and modelling steps before applications can be adapted. Second, the new generation of platforms and technologies underlying these devices as well as upcoming web standards HTML5 and CSS3 have partly changed the way in which web applications are implemented nowadays and often limit the way in which they can be adapted. In this paper, we present XCML as one example of a domain-specific language that tightly integrates context-aware concepts and adaptivity mechanisms to support developers in the specification and implementation of multi-channel web applications. In contrast to most existing approaches, the objective is to use a more lightweight approach to adaptation that can dynamically evolve and support new requirements as they emerge. Our solution builds on versioning principles in combination with a context matching process based on a declaration of context-dependent variants of content, navigation and presentation in terms of context expressions at different levels of granularity that are specific to the application. To support this, a formally defined context algebra is used to parse and resolve the context expressions at compile-time and to determine the best-matching variants with respect to the client context at run-time. We present the language concepts and a possible execution environment together with context-aware developer tools for the authoring and testing of adaptive features and behaviour. We also report on two case studies: the first shows how our general approach allows for integration with existing technologies to leverage advanced context-aware mechanisms in applications developed using other platforms and languages and the second how existing web interfaces can be systematically extended to support new adaptation scenarios.

2010, Leone, Stefania, Grossniklaus, Michael, de Spindler, Alexandre, Norrie, Moira C.

Web 2.0 users may publish a rich variety of personal data to a number of sites by uploading personal desktop data or actually creating it on the Web 2.0 site. We present a framework and tools that address the resulting problems of information fragmentation and fragility by providing users with fine grain control over the processes of publishing and importing Web 2.0 data.

2010, Nebeling, Michael, Grossniklaus, Michael, Leone, Stefania, Norrie, Moira C.

Context-awareness is a requirement in many modern web applications. While most model-driven web engineering approaches have been extended with support for adaptivity, state-of-the-art development platforms generally provide only limited means for the specification of adaptation and often completely lack a notion of context. We propose a domain-specific language for context-aware web applications that builds on a simple context model and powerful context matching expressions.