John A. Mariani

Supporting Cooperative Work in Virtual Environments

This paper explores the use of multi-actor virtual reality systems to support communication and cooperation between groups of people. In particular, it introduces a spatial model of interaction which aims to support people in using their natural social communication skills when working together. First, we briefly review some of the social science background which has informed the development of this model. Next, we define the models main concepts, i.e. aura, awareness, focus, nimbus, adapters and boundaries. We also explore the issues of user embodiment and spatial structure, the latter leading to the concept of Populaled Information Terrains. We then show how a few simplifying assumptions results in the notion of awareness states and discuss how these link to the results of previous studies of cooperative work. Following this, we present some early prototypes which realise our concepts within the DIVE distributed virtual reality system. In the first of these, a simple discrete version of the spatial model has been constructed based on the notion of awareness states. The second, Q-PIT, demonstrates an early Populated Information Terrain. Finally, we briefly reflect on the relationship between this work and other CSCW systems based on the metaphor of shared space

Supporting cooperative applications

Cooperative applications which have started to emerge from CSCW research place new demands on the computer technology used to support them. These demands raise a number of fundamental questions about the way in which computing systems provide application support. This paper examines a number of issues surrounding the support of cooperative applications and how they impact both CSCW and computer science research. In particular, the relationship between cooperative applications and the supporting techniques of distributed systems and database technology are investigated. Cooperative applications question many of the design assumptions embodied within these techniques, and ask far reaching questions of the technology. Traditionally, support systems have been unaware of cooperative activities and have hidden the actions of others from each user. This paper examines the implications of this choice and the need to consider alternative approaches to the provision of systems support. The paper concludes by highlighting a number of issues which need to be addressed both by computer science and CSCW reseachers.

Networked virtual reality and cooperative work

We explore the issue of supporting cooperative work using networked virtual reality. This exploration covers three major themes: supporting communication and awareness, structuring space, and embodying users. Correspondingly, three sets of concepts are introduced. The first is a spatial model of interaction, which defines the mechanisms of aura, awareness, focus, nimbus, and adapters to allow the inhabitants of virtual environments to flexibly manage their communication across a number of media. The second is a set of techniques for constructing Populated Information Terrains (PITS), abstract data spaces that support the cooperative browsing of information. The third is a set of design issues for virtual bodies. Each set of concepts is illustrated with a discussion of prototype applications implemented within our own DIVE and MASSIVE networked virtual reality systems.

The use of adapters to support cooperative sharing

This paper examines the importance of providing effective management of sharing in cooperative systems and argues for a specialised service to support the cooperative aspects of information sharing. The relationship between features of the cooperative shared object service and existing services is briefly examined. A number of management services of particular importance to CSCW systems are identified. The paper presents a technique of realising a shared object service by augmenting existing object facilities to provide management of their cooperative use. These facilities are realised through object adapters that provide additional cooperative facilities and greater control over the supporting infrastructure.

Representing design rationale to support innovative design reuse: a minimalist approach

The reuse of previous design knowledge is a potentially important way to improve design efficiency. In practice, however, design reuse is plagued with difficulties, including those associated with the indexing, retrieval, understanding and modification of prior design knowledge. We propose that such difficulties can be ameliorated by employing insights deriving from design-rationale research concerning how best to represent and retrieve design information. We illustrate these insights by describing the development of a design-reuse system that maximizes the benefits of rationale capture and information retrieval whilst minimising the costs to the designer that might arise from disruption to natural design work.

TripleSpace: an experiment in a 3D graphical interface to a binary relational database

Abstract Novel techniques of data visualization will be required to take full advantage of the advanced human-computer interaction technology now being developed as part of the virtual reality movement. In particular, meaningful three-dimensional representations will be of interest to users wishing to explore the data topology. An experimental system which offers a three-dimensional topology is presented in this paper; three sets of data representing interesting situations are described and viewed through the system.

Virtual Environments for Data Sharing and Visualisation — Populated Information Terrains

The Concept of Populated Information Terrains (PITS) aims to extend database technology with key ideas from the new fields of Virtual Reality (VR) and Computer Supported Cooperative Work (CSCW). PITS are virtual data spaces which support visualisation of, and cooperative work within, shared data. This paper identifies key techniques for building PITS for various types of database, including multi-dimensional visualisation, statistical approaches, graph drawing techniques and human centred approaches. We then discuss issues concerned with populating such terrains including communication between users, embodiment of users, peripheral awareness of others and the relation to database concurrency control. Finally, we describe a prototype implementation that demonstrates the concept of PITS and which helps clarifies key design issues for future full-scale implementations.

Oggetto: An object oriented database layered on a triple store

Interest in object oriented database (OODB) systems continues to grow. This paper describes the implementation of an OODB by layering over a triple store. The OODB thus implemented allows experimentation with an object-oriented query language. It is shown how this system, Oggetto, is capable of handling the four tasks outlined in ref.2

A knowledge-based operating system

The recent developments in ‘fifth generation’ computing, for example in the areas of programming environments and man-machine interfaces, have shown up inadequacies in the current generation of operating systems. In addition, most operating systems are designed to run on a single computer (uniprocessor or multiprocessor) and to provide a multi-programming environment. Consequently, they cannot realise the full potential offered by a new class of computer systems consisting of computers interconnected by a high-speed local area network. In this paper we present a proposal for an operating system kernel to meet these new demands. We concentrate on one particular aspect of the design – its knowledge base. It is suggested that a knowledge base can provide support for more intelligent systems. It is further suggested that this knowledge base should be at the heart of the operating system design. Some examples are presented to illustrate the use of a knowledge base to support more intelligent applications and to provide a better environment for the user.

Using subjective views to enhance 3D applications

Visualisations of virtual worlds by current Cooperative Virtual Environments (CVEs) are identical for each user, albeit from a different viewpoint. Users cannot tailor their representation of the virtual scene or the degree to which they are aware of other user’s activities. This paper describes the implementation of a mechanism to support subjective views of shared virtual worlds, and describes how this mechanism is utilised to enhance an existing 3D application.