Enabling collaboration in virtual reality navigators

In this paper we characterize a feature superset for Collaborative Virtual Reality Environments (CVRE), and derive a component framework to transform stand-alone VR navigators into full-fledged multithreaded collaborative environments. The contributions of our approach rely on a cost-effective and extensible technique for loading software components into separate POSIX threads for rendering, user interaction and network communications, and adding a top layer for managing session collaboration. The framework recasts a VR navigator under a distributed peer-to-peer topology for scene and object sharing, using callback hooks for broadcasting remote events and multicamera perspective sharing with avatar interaction. We validate the framework by applying it to our own ALICE VR Navigator. Experimental results show that our approach has good performance in the collaborative inspection of complex models.Postprint (published version

An Approach to Agent-Based Service Composition and Its Application to Mobile

This paper describes an architecture model for multiagent systems that was developed in the European project LEAP (Lightweight Extensible Agent Platform). Its main feature is a set of generic services that are implemented independently of the agents and can be installed into the agents by the application developer in a flexible way. Moreover, two applications using this architecture model are described that were also developed within the LEAP project. The application domain is the support of mobile, virtual teams for the German automobile club ADAC and for British Telecommunications

On Consistency and Network Latency in Distributed Interactive Applications: A Survey—Part I

This paper is the first part of a two-part paper that documents a detailed survey of the research carried out on consistency and latency in distributed interactive applications (DIAs) in recent decades. Part I reviews the terminology associated with DIAs and offers definitions for consistency and latency. Related issues such as jitter and fidelity are also discussed. Furthermore, the various consistency maintenance mechanisms that researchers have used to improve consistency and reduce latency effects are considered. These mechanisms are grouped into one of three categories, namely time management, Information management and system architectural management. This paper presents the techniques associated with the time management category. Examples of such mechanisms include time warp, lock step synchronisation and predictive time management. The remaining two categories are presented in part two of the survey

DIVE on the internet

This dissertation reports research and development of a platform for Collaborative Virtual Environments (CVEs). It has particularly focused on two major challenges: supporting the rapid development of scalable applications and easing their deployment on the Internet. This work employs a research method based on prototyping and refinement and promotes the use of this method for application development. A number of the solutions herein are in line with other CVE systems. One of the strengths of this work consists in a global approach to the issues raised by CVEs and the recognition that such complex problems are best tackled using a multi-disciplinary approach that understands both user and system requirements. CVE application deployment is aided by an overlay network that is able to complement any IP multicast infrastructure in place. Apart from complementing a weakly deployed worldwide multicast, this infrastructure provides for a certain degree of introspection, remote controlling and visualisation. As such, it forms an important aid in assessing the scalability of running applications. This scalability is further facilitated by specialised object distribution algorithms and an open framework for the implementation of novel partitioning techniques. CVE application development is eased by a scripting language, which enables rapid development and favours experimentation. This scripting language interfaces many aspects of the system and enables the prototyping of distribution-related components as well as user interfaces. It is the key construct of a distributed environment to which components, written in different languages, connect and onto which they operate in a network abstracted manner. The solutions proposed are exemplified and strengthened by three collaborative applications. The Dive room system is a virtual environment modelled after the room metaphor and supporting asynchronous and synchronous cooperative work. WebPath is a companion application to a Web browser that seeks to make the current history of page visits more visible and usable. Finally, the London travel demonstrator supports travellers by providing an environment where they can explore the city, utilise group collaboration facilities, rehearse particular journeys and access tourist information data

Supporting awareness in heterogeneous collaboration environments

Rapid technological advancements have made it possible for humans to collaborate as never before. However demands of group work necessitate distributed collaboration in very heterogeneous environments. Heterogeneity as in various applications, platforms, hardware and communication infrastructure. User mobility, lack of availability and cost often make imposing a common collaboration environment infeasible. Awareness is essential for successful collaboration. Awareness is a key design criterion in groupware but often collaboration occurs with applications not designed to support useful awareness. This dissertation deals with the issue of effective group awareness support in heterogeneous environments.;Awareness propagation is effective if the appropriate amount of information, relevant to the user\u27s sphere of activity is delivered in a timely, unobtrusive fashion. Thus issues such as information overload, and distraction have to be addressed. Furthermore ability to establish the appropriate balance between awareness and privacy is essential. Enhanced forms of awareness such as intersubjectivity and historical awareness are often invaluable. Heterogeneous environments significantly impact the above quality factors impeding effective awareness propagation. Users are unable to tailor the quality of awareness received.;Heterogeneity issues that affect awareness quality are identified. An awareness framework is proposed that binds various sources of awareness information. However for effective awareness support, physical integration must be augmented by information integration. As a solution, an awareness model is proposed. Specification of the awareness model and framework\u27s architecture and features is the key contribution. The proposed model has been validated through simulations of realistic collaboration involving human participation. Scenarios created, have tested the model\u27s usefulness in enhancing the quality of group work by propagating effective awareness among users. To accomplish the same, an Awareness Simulator application has been created. In the validation process, efforts made to create an experimental methodology revealed some techniques related to awareness evaluation in CSCW, which are proposed. Various issues required to successfully engineer such awareness frameworks are identified and their impact on requirements such as security and performance, discussed. With various standards and technologies that can be harnessed to create awareness frameworks, there is great promise that barriers in heterogeneous collaboration environments can be overcome

On extending collaboration in virtual reality environments

We characterize the feature superset of Collaborative Virtual Reality Environments (CVREs) out of existing implementations, and derive a novel component framework for transforming standalone VR tools into full-fledged multithreaded collaborative environments. The contributions of our approach rely on cost-effective techniques for loading graphics rendering, user interaction and network communications software components into separate threads, with a top thread for session collaboration. The framework recasts VR tools under a scalable peer-to-peer topology for scene sharing, callback hooks for event broadcasting and multicamera perspectives of avatar interaction. We validate the framework by applying it to our own Alice VR navigator. Experimental results show good performance of our approach in the collaborative inspection of complex models.Postprint (published version

Investigations of collaborative design environments: A framework for real-time collaborative 3D CAD

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This research investigates computer-based collaborative design environments, in particular issues of real-time collaborative 3D CAD. The thesis first presents a broad perspective of collaborative design environments with a preliminary case study of team design activities in a conventional and a computer mediated setting. This study identifies the impact and the feasibility of computer support for collaborative design and suggests four kinds of essential technologies for a successful collaborative design environment: information-sharing systems, synchronous and asynchronous co- working tools, project management systems, and communication systems. A new conceptual framework for a real-time collaborative 3D design tool, Shared Stage, is proposed based upon the preliminary study. The Shared Stage is defined as a shared 3D design workspace aiming to smoothly incorporate shared 3D workspaces into existing individual 3D workspaces. The addition of a Shared Stage allows collaborating designers to interact in real-time and to have a dynamic and interactive exchange of intermediate 3D design data. The acceptability of collaborative features is maximised by maintaining consistency of the user interface between 3D CAD systems. The framework is subsequently implemented as a software prototype using a new software development environment, customised by integrating related real-time and 3D graphic software development tools. Two main components of the Shared Stage module in the prototype, the Synchronised Stage View (SSV) and the Data Structure Diagram (DSD), provide essential collaborative features for real-time collaborative 3D CAD. These features include synchronised shared 3D representation, dynamic data exchange and awareness support in 3D workspaces. The software prototype is subsequently evaluated to examine the usefulness and usability. A range of quantitative and qualitative methods is used to evaluate the impact of the Shared Stage. The results, including the analysis of collaborative interactions and user perception, illustrate that the Shared Stage is a feasible and valuable addition for real-time collaborative 3D CAD. This research identifies the issues to be addressed for collaborative design environments and also provides a new framework and development strategy of a novel real-time collaborative 3D CAD system. The framework is successfully demonstrated through prototype implementation and an analytical usability evaluation.Financial support from the Department and from the UK government through the Overseas Research Studentship Awards