Klaus Meissner

Engineering the Presentation Layer of Adaptable Web Information Systems

Engineering adaptable Web Information Systems (WIS) requires systematic design models and specification frameworks. A complete model-driven methodology like Hera distinguishes between the conceptual, navigational, and presentational aspects of WIS design and identifies different adaptation “hot-spots” in each design step. This paper concentrates on adaptation in the presentation layer and combines the modeling power of Hera with the versatile presentation capabilities of the AMACONT project. After discussing different aspects of presentation layer adaptation, the layout manager mechanism of AMACONT for describing the adaptable layout of ubiquitous Web presentations is introduced. Then the RDFS-based Hera schema for presentation models is presented, allowing to assign AMACONT layout descriptors to Hera slices. According to this formalization, Hera application model instances are automatically transformed to a component-based AMACONT implementation that can be adjusted to different end devices and output formats. The XML-based transformation process is explained in detail, and the resulting methodology is exemplified by a prototype application.

Intelligent multimedia presentations in the Web: fun without annoyance

Abstract Multimedia presentations for the Web increasingly attract attention. With the growth of the Internet and the expressiveness of multimedia, there are new possibilities for advertising and electronic shopping. To improve the acceptance of customers and to realize “new shopping fun” without annoyance, it seems necessary to develop a system that adapts the product presentation to the interest of the customers, their media preferences and the hardware and software preconditions. This paper introduces the TELLIM system which offers these features for multimedia presentations in the web by using an incremental learning algorithm.

CroCo: Ontology-Based, Cross-Application Context Management

Context-awareness is a key issue for future applications within heterogeneous and networked environments. In terms of efficiency and reusability, such applications should be separated from the problems of context gathering and modeling, but should instead profit from and contribute to cross-application context information. For this purpose, an ontology-based, cross-application context modeling and management service is needed to provide appropriate support for the variety of conceivable application scenarios. Although there have been numerous approaches dealing with application-independent context management, none of them sufficiently supports the vision of cross-application context handling. Therefore, we present CroCo, an ontology-based context management service that allows for cross-application context gathering, modeling, and provision. We verified and tested the practicability of our concept within two different projects with disparate application scenarios.

Metadata generation and consolidation within an ontology-based document management system

A central issue for the benefit and success of an ontology-based personal document management system is its capability to automatically model appropriate and valid document descriptions. The generation process primarily depends on the application context and should be customised accordingly. Furthermore, automatically generated information needs appropriate cleaning and consolidation to maintain a certain level of data quality. Therefore, this paper presents a semantic document management system which applies a stepwise knowledge modelling process. Our approach separately addresses the problems of general translation of diverse information sources, syntax check, normalisation and duplication and conflict handling, based on consecutive and configurable stages.

Adaptation and Distribution of Pipeline-Based Context-Aware Web Architectures

The dynamic generation of context-aware applications for the ubiquitous Web is very time consuming and causes significant server load. Therefore, optimizing the efficiency of the publishing process and reducing server load by dynamically configuring system components are key factors for the commercial success of context-aware Web applications. To meet this challenge, this paper presents a framework that dynamically adjusts the architecture of pipeline-based context-aware Web systems either by adapting or omitting server tasks, distributing load within server clusters, or migrating load to client devices. The system adaptation and distribution are performed according to varying load rates and system context states that are monitored permanently. Furthermore, the paper also presents experiences gained by the implementation of prototypes and illustrates several useful application scenarios that are supported by the proposed mechanisms.

Developing component-based adaptive Web applications with the AMACONTBuilder

The growing need for personalization and device independence calls for effective ways of engineering adaptive Web applications. This requires formats, languages and structured process models that allow developers to design and express adaptation, but also appropriate authoring tools. Still, current Web authoring tools do not provide sufficient adaptation support. Recently, the AMACONT project introduced a component-based document format aiming at efficiently composing adaptive Web applications from reusable Web components. This paper focuses on the development of such applications and presents a visual authoring tool called AMACONTBuilder. Based on a structured authoring process it is shown how it can be utilized for effectively creating AMACONT applications.

Generation and Maintenance of Semantic Metadata for Personal Multimedia Document Management

Personal multimedia document management benefits from Semantic Web technologies. However, an ontology-based document management system has to meet a number of challenges regarding flexibility, soundness, and controllability of the semantic data model. This paper presents an integrated approach for ontology-based multimedia document management, which covers the process of automated modeling of semantic descriptions for multimedia objects and allows for the domain-specific customization of the used ontology. Furthermore, the proposed approach addresses the problems of data validation and consolidation to ensure semantic descriptions of proper quality. We demonstrate the practicability of our concept by a prototypical implementation of a service platform for personal information management applications.

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.

Sharing Composite Web Applications with Multiple Coupling Levels

Developing and utilizing situational long-tail Web applications for scenarios with multiple persons interacting gains increasing importance. Thereby, adjusting the style of coupling during runtime is necessary to support changing situational requirements and long-tail collaborative situations. Main problems comprise the lack of universal coupling levels which are characterized in a sufficient and understandable granularity, missing analyses for potential synchronization points in the context of black-box-based Web applications, and an adequate user interface (UI) support for managing and reviewing individual coupling levels for multiple users simultaneously. To this end, we present a novel concept for managing different levels of coupling within composite Web applications. The seven proposed sharing modes support Web users with no programming skills by a default configuration of couplings, permissions and sharing objects. A wizard-like interaction concept enables these users to create and manage personal sharing definitions during runtime while considering various levels of coupling for each collaborative partner. A first user study provides preliminary evidence about the acceptance of the sharing modes and the interaction features for the target group.