61,098 research outputs found
Development of a Physics-Aware Dead Reckoning Mechanism for Distributed Interactive Applications
Distributed Interactive Applications (DIAs) are a class of software that allow
geographically remote users to interact within a shared virtual environment.
Many DIAs seek to present a rich and realistic virtual world to users, both on a
visual and behavioural level. A relatively recent addition to virtual environments
(both distributed and single user) to achieve the latter has been the simulation of
realistic physical phenomena between objects in the environment.
However, the application of physics simulation to virtual environments in DIAs
currently lags that of single user environments. This is primarily due to the
unavailability of entity state update mechanisms which can maintain consistency
in such physics-rich environments. The difference is particularly evident in
applications built on a peer-to-peer architecture, as a lack of a single authority
presents additional challenges in synchronising the state of shared objects while
also presenting a responsive simulation.
This thesis proposes a novel state maintenance mechanism for physics-rich
environments in peer-to-peer DIAs composed of two parts: a dynamic authority
scheme for shared objects, and a physics-aware dead reckoning model with an
adaptive error threshold. The first part is intended to place a bound on the
overall inconsistency present in shared objects, while the second is implemented
to minimise the instantaneous inconsistency during users’ interactions with
shared objects. A testbed application is also described, which is used to validate
the performance of the proposed mechanism.
The state maintenance mechanism is implemented for a single type of physicsaware
application, and demonstrates a marked improvement in consistency for
that application. However, several flexible terms are described in its
implementation, as well as their potential relevance to alternative applications.
Finally, it should be noted that the physics-aware dead reckoning model does not
depend on the authority scheme, and can therefore be employed with alternative
authority scheme
Update propagation for peer-to-peer-based massively multi-user virtual environments
Over the last decade Massively Multi-user Virtual Environments (MMVEs) have become an integral part of modern culture and business. Applications for these large-scale virtual environments range from gaming to business and scientific research. Some MMVEs reach a user base in the tens of millions and the total number of users is estimated in the billions. Despite this success, launching an MMVEs is still a risky proposition. This is in large part due to the high cost associated with setting up and maintaining the necessary server infrastructure. One way of reducing the costs of operating MMVEs is to switch their system architecture from the current client/server-based model to one based on peer-to-peer (P2P) technologies. This has the potential to significantly reduce the infrastructure costs of MMVEs, as users bring their own resources into the P2P system and servers are no longer required, thus decreasing expenses and market entry barriers. This thesis describes a scalable and low-latency update propagation system for P2P-based MMVEs. Update propagation refers to the exchange of information about changes in the virtual environment between users and is one of the key components of MMVEs. Thus, the described system represents a key step towards operating MMVEs as fully distributed peer-to-peer systems
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