Matthias Niederhausen

Complementary assistance mechanisms for end user mashup composition

Despite several efforts for simplifying the composition process, learning efforts required for using existing mashup editors to develop mashups remain still high. In this paper, we describe how this barrier can be lowered by means of an assisted development approach that seamlessly integrates automatic composition and interactive pattern recommendation techniques into existing mashup platforms for supporting easy mashup development by end users. We showcase the use of such an assisted development environment in the context of an open-source mashup platform Apache Rave. Results of our user studies demonstrate the benefits of our approach for end user mashup development.

Harnessing the Power of Semantics-Based, Aspect-Oriented Adaptation for amacont

Adaptivity in web applications raises several concerns. One demands it to be decoupled from the actual application and at the same time wants to use very domain-specific terms for dividing the audience into groups. Two current trends, aspect-oriented programming and semantic web technologies, fit these requirements like a glove. In this paper, we present the Amacont web modeling framework and use it as an example of how to extend such a framework to make use of these powerful technologies. The underlying concepts, however, can be applied to the modeling of adaptivity in general.

From Choreographed to Hybrid User Interface Mashups: A Generic Transformation Approach

Inter-widget communication (IWC) becomes an increasingly important topic in the field of user interface mashups. Recent research has focused on so-called choreographed IWC approaches that enable self-organization of the aggregated components based on their messaging capabilities. Though a manual configuration of communication paths is not required anymore, such solutions bear several problems related to awareness and control of the emerging message flow. This paper presents a systematic approach to tackle these problems in the context of hybrid user interface mashups. We show how users can be made aware of the emerged IWC configuration and how they can adjust it to their needs. A reference architecture for development of hybrid mashup platforms, is derived and one implementation based on the publish-subscribe choreography model is given. We report on the results of a first user study and outline directions for the future research.

Web-Based Support by Thin-Client Co-browsing

As web applications are becoming ever larger, more complex and thus more demanding for their users, there is a growing need for customer support. Very often, it is provided by support centers via phone. However, the media break between browser and phone hampers the common understanding of user and consultant. As a result, support becomes ineffective and expensive, and users get frustrated. Screen sharing solutions are one possible solution for this problem, but they have major disadvantages like high bandwidth requirements, slow performance and, most importantly, the need for a client-side installation. These drawbacks are addressed by VCS, a concept and system for “instant co-browsing”, that runs directly within the user’s browser. It equally allows all participants of a support session to see and navigate the same web page on their screens, being aware of what the other person is currently doing on the page. People can directly interact with each other, jointly complete tasks and solve. The event-based nature of the synchronization approach to be presented further facilitates adaptation, so that users with heterogeneous end devices may collaborate. In this chapter, we present VCS and also discuss the special challenges that this approach entails.

Web Software Evolution by Aspect-oriented Adaptation Engineering

The evolving nature of the WWW necessitates to constantly adapt Web applications to new requirements, audiences, and client devices. However, as a given adaptation concern (e.g., device dependency) is typically deeply intertwined with different parts of the underlying application, it becomes difficult to adjust a Web-based systems adaptive behavior to a new requirement. In this paper, we provide an aspect-oriented view on adaptation engineering within the AMACONT framework. By separating the specification of adaptation from the underlying application in the form of so-called adaptation aspects, we can thus easily add new or modify existing adaptation concerns on demand. We also present an extension of our graphical authoring tool AMACONTBuilder, allowing Web engineers to intuitively incorporate adaptation aspects into Web applications.

HyperAdapt: Enabling Aspects for XML

Aspect orientation offers an intuitive way to specifiy adaptivity for web applications, but despite its advantages, the approach still lacks acceptance. We argue that there are two main reasons for this: First, aspects make implicit assumptions on the underlying system and can thus produce invalid behavior if that system is changed. Second, the lack of concepts for dealing with aspect interactions places a heavy burden on the use of multiple aspects. In this paper we discuss how HyperAdapt addresses these problems, paving the road towards a productive use of aspect orientation in the domain of web applications.

Detecting and resolving conflicts between adaptation aspects in multi-staged XML transformations

Separation of Concerns (SoC) is a common principle to reduce the complexity of large software and hypermedia systems. Amongst a variety of approaches, adaptation aspects are a well-known solution to significantly improve SoC in adaptive hypermedia applications. To model adaptation aspects in XML-based hypermedia applications, we developed PX-Weave, a tool which allows to specify and weave such aspects in multi-staged XML transformation environments. However, while aspects increase modularity and thus decrease complexity of software, they do also introduce some complex problems. The most prominent one, aspect interaction, has received a lot of attention from researchers during the last decade. In this paper we investigate the problem of aspect interaction for adaptation aspects. We present a combined approach for static and dynamic detection of aspect interactions in multi-staged XML-based hypermedia applications, which we implemented as an add-on to PX-Weave.