Making annotations on books and learning materials is part of students' everyday life. Although there are many computer-based annotation systems, many people prefer to print digital documents and make annotations on physical paper. We introduce a classification scheme for computer-based annotation systems and provide an overview of different systems using this scheme. During our investigations, we identified several shortcomings in existing annotation systems: limitation to single document formats, no capturing of relations to reflect lateral reading, loss of context information an annotation was created in and limited sharing capabilities among collaborative users. To overcome these shortcomings, we introduce the concepts of Anchor Points, Artefacts and Spaces. Anchor Points define locations in arbitrary documents. Artefacts capture annotations on multiple Anchor Points in several documents, allowing students to map their current working context that typically contains several open documents and a relationship between them. Spaces are repositories for the learning materials and annotations that are automatically replicated among collaborative mobile users.jca_297 219..237

No abstract

UbiSettlers is a prototype of a mobile multiplayer game for hybrid networks running on real hardware. It uses dynamic adaptation and topology control mechanisms to deal with problems inherent to ad hoc and wireless infrastructured networks. In particular, a globally consistent view on the game's state is not mandatory. This is facilitated by resolving inconsistencies through appropriate integration into the semantics of the game itself. In addition to that, we focus also on network feedback to integrate changing network topologies into the game. Moreover, stimulating cooperation is another major facet of the game design and implementation.

To efficiently support collaborative semantic management of digital resources, this article introduces MetaSemflow, a vertical semantic flow of metadata integration to capitalize on the diversity of metadata sets available for any given digital resource among various communities (cultural, linguistical, architectural, historical, or multidisciplinary communities). MetaSemflow proposes a metadata vertical integration by combining a multi-faceted resource categorization approach to a topic maps-based semantic management including contextual semantics (e.g. 5W1H model). This innovative approach has been used by the Isfahan Islamic Architecture Database (IIAD) Project.

Mobile devices, such as laptops, smartphones, and PDAs are nowadays widely used. One essential daily task, among others, is the sharing of files, e.g. podcasts, pictures, or learning material, with others. The dynamic nature of mobile networks, together with the limited bandwidth, make common file sharing protocols unsuitable for such dynamic environments. In this paper two different strategies for the dissemination of files in mobile networks are introduced. Both approaches are evaluated based on different criteria, such as the file size and the level of interest. The first strategy is based on the en-passant communication pattern, which is a peer-to-peer approach between local one-hop neighbors. The second approach employs a clustering algorithm for mobile networks.