Angie Chandler

Toward emergent technology for blended public displays

Public displays are becoming increasingly commonplace, yet recent studies place the effectiveness and user acceptance of them into doubt. This paper motivates the need for a new class of display technology that can more effectively blend with its environment and introduces the concept of self-organizing emergent displays as a vehicle to achieving this. The paper goes on to briefly describe Firefly, a prototype emergent display system, and evaluate its scalability, effectiveness, and user acceptance through experimental analysis and a field trial.

On the effects of loose causal consistency in mobile multiplayer games

It is well understood that distributed multiplayer games, as soft real-time systems, require a degree of support from the underlying network in order to function correctly, in terms of predictable end to end bandwidth, latency and jitter. In a mobile environment, such applications face even greater challenges, as the latency of wireless networks is much higher than their wireline counterparts, jitter is often much higher due to network handoff and bandwidth is at a premium. In fact, the latency of many wide area wireless networks is beyond the tolerance of most multiplayer games, rendering such applications unusable.This paper presents the design and experimental evaluation of Rendezvous, a novel decentralized consistency management mechanism that enables the collaboration of multiple players in mobile real-time games, even in a high latency environment. The operation of the mechanism is validated through the analysis of a real world example - a distributed mobile multiplayer soccer game called Knockabout, which is designed to operate on the Smartphone platform. Experimental results are included not only comparing Rendezvous to an existing consistency mechanism, but also measuring the length of network delay tolerated by the platform and its effect on the players.

Rendezvous: supporting real-time collaborative mobile gaming in high latency environments

Despite the ever increasing popularity of handheld, networked gaming consoles, fully interactive real-time, multiplayer games designed for these platforms have yet to become a reality. This is primarily caused by the reliance of these handheld devices on telecoms networks such as GPRS and 3G to enable communications between players, introducing network latencies beyond the capacity of existing games and supporting consistency mechanisms to operate successfully.This paper motivates the need for a new approach to consistency in mobile multiplayer gaming environments, and introduces Rendezvous, a novel solution to the high latency consistency problem, based on the concept of elegant recovery from an inconsistent shared state, rather than the more traditional approach of prevention of the initial inconsistency. The paper goes on to present preliminary design, implementation and evaluation of Rendezvous, with respect to its application to a mobile real-time multiplayer game written for the smart phone platform called Knockabout.

Digging into Concurrency

The topic of this paper is the design and implementation of an interacting Lego digger and dumper truck through the use of Petri nets. The focus of this is primarily on the use of Petri nets in the developing of dependable systems, an area of particular concern in the full-size equivalent of our experiment. The content of this paper will discuss the progression of the Petri net model of these two Lego robots, from design to implementation, and finally evaluation. The paper also features an optional plug-in Petri net, intended to allow the dumper to authenticate the digger for added security.

Rendezvous: an alternative approach to conflict resolution for real time multi-user applications

Up until now little support has been provided for shared state systems in environments with highly unpredictable network connections, such as mobile networks. Shared state conflict management has instead been focused on more stable network environments, such as the Internet, where delays may occur but where the high latency and frequent disconnection that can plague mobile networks are relatively uncommon. As the need for real-time multiuser applications in these less predictable environments increases, this inevitably affects the design of conflict management in shared state systems. Rendezvous is a set of protocols intended to maintain synchronization of shared state between clients collaborating over a distributed, real-time environment where high latency and frequent disconnection are likely. Key to Rendezvous is the idea that when a conflict occurs the conflicting entities need not rollback processes in order to resolve the difficulties but instead take into account their mutual targets and agree on a state in which they converge at a later time. This paper details the earliest experiments in the design and implementation of Rendezvous as we study the feasibility of the approach.