An Architecture for Large-scale Virtual Interactive Communities

Abstract

Following the popularity of text-based Internet chat channels and instant messaging applications, virtual interactive communities are often advertised as ‘revolutionary’ applications that allow large groups of people to share ideas, experiences and make new friends. What is largely unknown by the general public is that these applications share the underlying technology with networked computer games, and were founded in research for military purposes. We start this dissertation by analyzing the behavior (in terms of bandwidth usage) of applications based on networked virtual environments technology, such as networked games and virtual interactive communities. Also, the impact of common network-related problems, in this case delay and jitter, on user performance and perceived quality is quantified. Afterwards, we discuss the development of ALVIC, an Architecture for Large-scale Virtual Interactive Communities. The unique feature of ALVIC is certainly its scalability, enabling both large amounts of simultaneous users to interact, as well as allowing them to experience the vastness of a virtual world. Several building blocks make up the ALVIC framework, starting with the subsystem that enables users to view the three dimensional world on computing devices located all over the world. It is of prime importance that each of the participants is, at any one time, looking at the same world. We will describe how messages are exchanged between users, using advanced network techniques that enable efficient distribution to large groups of people. Also, a mechanism for the simulation of large audiences is described using software that emulates behavior of human users using elementary artificial intelligence techniques. Furthermore, the ability for people to interact directly, through means of video communication, is integrated into the ALVIC architecture. Especially when considering large audiences, the requirement of controlling bandwidth is stringent. Also, due to limitations in resource availability on a computer, optimizations are included to increase the subjective quality of experience. Finally, as ALVIC was designed to be used as foundation for the deployment of a range of applications, from games to teleconferencing systems, we will look at the upcoming market of mobile applications. We will show that it is feasible to deploy applications based on the ALVIC architecture on a range of devices, taking into account their individual limitations