User-Oriented Authorization in Collaborative Environments

Access rights for collaborative systems tend to be rather complex, leading to difficulties in the presentation and manipulation of access policies at the user interface level. We confront a theoretical access rights model with the results of a field study which investigates how users specify access policies. Our findings suggest that our theoretical model addresses most of the issues raised by the field study, when the required functionality can be presented in an appropriate user interface

Supporting Tailorability of Groupware through Component Architectures

Tailorability is generally regarded as a key property of CSCW-systems, because cooperative activities provide for very dynamic and diversified requirements. Extensive tailorability has to be supported by the architecture of the application, which is determined by the design of the groupware platform. This contribution points out the value of a scaleable component architecture for groupware applications and raises some research questions concerning this approach. We propose a model of a tailorable architecture for CSCW-systems, which is based on the component paradigm. The architectural model supports tailoring activities by changing parameter settings of single components, changing the composition of components, and changing the implementation of components. Hierarchical composition of components allows for tailoring operations on different levels of abstraction and complexity. We introduce the concepts of tailoring constraints, tailoring constructs, and tailoring rights, which allow a..

Beyond ‘yes or no’—Extending access control in groupware with awareness and negotiation. Group Decision and Negotiation

We present three scenarios concerning access to documents in three real world fields of application, which have in common that they are very difficult to support with classical anticipative access control systems. We show, how- based on a highly configurable notification and negotiation service, which is tightly integrated with a classical access control system – the common permission and denial options can be extended with awareness and negotiation and how this approach supports the three initial access scenarios. We also introduce our implementation of the notification and negotiation service in the POLITeam project

The Evolve Project: Component-Based Tailorability for CSCW Applications

Tailorability is generally regarded as a key property of groupware systems due to the dynamics and differentiation of cooperative work. This article investigates the use of software components as a generic architectural concept for designing tailorable groupware applications. First, the issues raised by this approach are discussed in the context of an exploratory experiment during which component-based tailorability was applied to a real tailoring problem in the POLITeam project. The experiment's results led us to concentrate on questions concerning the support of distributed CSCW applications. As a consequence, we have developed the EVOLVE platform whose design concepts are described. Furthermore, a concrete example for the application of the approach to the design of a tailorable distributed coordination tool is given. We discuss related work, summarize the current state of the component-based tailorability approach and propose venues of further research. 1. Introduction While only..

How to Make Software Softer -- Designing Tailorable Applications

The design of tailorable systems is an important issue for fields of application which are characterized by differentiation and dynamics. We show how tailorability can be combined with approaches of evolutionary and participative software-engineering and discuss some conceptual problems arising from this approach. Moreover, we present two case studies on how to design tailorable functionality in a groupware development project