Anja Haake

Take CoVer: exploiting version support in cooperative systems

Current CSCW applications support one or more modes of cooperative work. The selection of and transition between these modes is usually placed on the users. At IPSI we built the SEPIA cooperative hypermedia authoring environment supporting a whole range of situations arising during collaborative work and the smooth transitions between them. While early use of the system shows the benefits of supporting smooth transitions between different collaborative modes, it also reveals some deficits regarding parallel work, management of alternative documents, or reuse of document parts. We propose to integrate version support to overcome these limitations. This leads to a versioned data management and an extended user interface enabling concurrent users to select a certain state of their work, to be aware of related changes, and to cooperate with others either asynchronously or synchronously.

CoVer: a contextual version server for hypertext applications

Key problems of version support for hypertext systems arise from the fine-grained, heavily interlinked structure of hyperdocuments. Integration of version support aggravates cognitive overhead problems during version creation and disorientation during version selection. Starting from the need to support versioning in our hypermedia publishing environment, we designed the CoVer hypermedia version. server. CoVer maintains context information with the versions that guides version creation and in particular helps in version identification. The key concept is task tracking: Users change their network in order to perform a task. These tasks can guide meaningful, automatic version creation. Being stored persistently as contextual version information they serve version identification. Moreover, CoVer maintains the derivation history of hyperdocuments across document boundaries and tracks the influence of annotations on the creation of new versions and the start-up of new tasks.

VerSE: towards hypertext versioning styles

Much of the previous work on version support for hypertext has focused primarily on the development of functionality for specific hypertext systems and/or a specific hypertext ap plication domain. Although these models address crucial version support problems in specific hypertext application domains, they cannot be easily adapted and then integrated into other hypertext applications. Hypertext version support environments have been introduced to help alleviate these problems. They are de signed to meet the version support needs of a wide range of hypertext applications. However , so far few high level versioning facilities have been constructed in these environ ments, creating a gap between the facilities provided direct ly within the environment and the versioning needs of some applications. The intent of this research is to bridge this gap. It turned out that task-based versioning styles are easy to use by both hy pertext application developers and hypertext application us ers. As shown in previous work, task-based versioning helps to alleviate cognitive overhead and disorientation problems for users. In addition, it requires little investment from the point of view of application development, since task-based versioning does not necessarily require an application to in corporate an extra notion for individual versions. This paper presents a set of task-based hypertext versioning styles that are offered in the VerSE flexible version support environ ment and shows the direction towards the design of addition al versioning styles.

Under CoVer: the implementation of a contextual version server for hypertext applications

At GMD-IPSI we are developing CoVer, a contextual version server for hypertext applications. Another characterization of CoVer is that CoVer integrates state-oriented versioning concepts with task-oriented versioning concepts. While other version models in general support only one of these groups of concepts, we argue that the explicit composition of versions of complex hypertext networks has to be complemented by automatic version creation in the context of tasks or jobs performed while manipulating the hypertext network and vice versa. Regarding the implementation of version models, it turns out that the state-oriented implementation approach—representing every legal state of a hyperdocument explicitly—and the task-oriented implementation approach—computing versions of complex hypertext networks due to changes executed during a task or job—are interchangeable. While the separation of state- and task-oriented concepts at the conceptual level of the version model is desireable to support version creation and selection for different hypertext applications, the implementation of such a dual model can be based on a single implementation approach. This paper discusses both types of implementation with an emphasis to cope with alternative versions that are in particular meaningful for hypertext publishing applications.

Things change: deal with it! versioning, cooperative editing and hypertext

A document that is in active use is generally one that is changing. Version control provides one way to control the disruptive effects of change without the worse solution of preventing or obstructing it. This panel will examine the relevance and problems of version control, with an emphasis on the topic of collaboration support. Despite ha long history in the hypertext communhy (usually as something to be added in tie future), the topics of shared editing and revision control remain complex, controversial and frequently misunderstood. Now that a really large public hypertext has come into existence, the issues of long-term maintenance and referential integrity are coming to the fore. The panel will give an overview of the fundamental issues, as well as a selection of arguments for and against different approaches to the issues. It builds on the perspective the presenters have gained from their own research, as well as their workshops on Hypertext and version control at ECHT ’94 and ECSCW ’95.

CURE – Eine Umgebung für selbstorganisiertes Gruppenlernen (CURE – an Environment for Self-Organized Collaborative Learning)

Zusammenfassung CURE unterstützt selbstorganisiertes kooperatives Lernen in verteilten Gruppen über das Internet. Verteilte Teams können sich mit CURE finden und in CURE ihr gemeinsames Lernen selbst organisieren sowie in gemeinsamen Arbeitsbereichen Lernmaterial kooperativ bearbeiten und synchron bzw. asynchron miteinander kommunizieren. Erste Erfahrungen aus dem Pilotbetrieb an der FernUniversität in Hagen zeigen, dass die Benutzer von CURE die Konzepte zur flexiblen Gestaltung des Gruppenlernens erfolgreich anwenden.

The VerSE version support environment (abstract)

M1che1 Crampen L612P EMA-EER1E mcrampe5 • 501e11.en5m-a1e5. fr