A realistic distributed interactive application testbed for static and dynamic entity state data acquisition

Marshall, Damien; McCoy, Aaron; Delaney, Declan; McLoone, Séamus; Ward, Tomás E.

doi:10.1049/cp:20040522

Cited by 5 publications

(6 citation statements)

References 4 publications

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“…Data was recorded from a number of users for two distinct environments as described in (Delaney et al 2003b;Marshall et al 2004a;Marshall et al 2004b). Each user navigated from a fixed start location to a fixed end location and the trajectories they traced out were sampled using both dead reckoning and the HSM.…”

Section: Simulations and Resultsmentioning

confidence: 99%

A novel convergence algorithm for the hybrid strategy model packet reduction technique

Delaney¹,

McLoone²,

Ward³

2005

IEE Irish Signals and Systems Conference 2005

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__________________________________________________________________________________________Abstract -Several approaches exist for maintaining consistency in Distributed Interactive Applications. Among these are techniques such as dead reckoning which use prediction algorithms to approximate actual user behaviour and thus reduce the number of update packets required to maintain spatial consistency. The Hybrid Strategy Model operates in a similar way, exploiting long-term patterns in user behaviour whenever possible. Otherwise it simply adopts a short-term model. A major problem with these techniques is the reconstruction of the local behaviour at a remote node. Using the modelled dynamics directly can result in unnatural and sudden jumps in position where updates occur. Convergence algorithms are thus required to smoothly reconstruct remote behaviour from discontinuous samples of the actual local behaviour. This paper makes two important contributions. Primarily, it proposes a novel convergence approach for the Hybrid Strategy Model. Secondly, and more fundamentally, it exposes a lack of suitable and quantifiable measures of different convergence techniques. In this paper the standard smoothing algorithm employed by DIS is used as a benchmark for comparison purposes. Keywords -Hybrid Strategy Model, Convergence, Distributed Interactive Applications __________________________________________________________________________________________ I INTRODUCTIONTechniques that generate and transmit approximate models of local user behaviour have been developed to reduce the number of update packets that must be transmitted between participants of Distributed Interactive Applications (DIAs). One such technique is dead reckoning, which reduces network traffic by preventing update packets from being sent if the local participant's position has not varied from a model of that position by a pre-established threshold (IEEE 1993; IEEE 1995). However, dead reckoning ignores information pertaining to the structure of the environment, the historical behaviour of users within the environment and the objectives of the users within the environment. Consequently a technique known as the Hybrid Strategy Model or HSM has recently been developed which exploits this information by identifying long-term patterns in user behaviour. By combining these longer-term models or strategies with a short term model, such as dead reckoning, a reduction in network traffic has been shown (Delaney et al. 2003b;Delaney et al. 2003a;Marshall et al. 2004a;McCoy et al. 2005).An important issue arising from this approximation of local user behaviour is the reconstruction of a faithful replication at a remote location given this often divergent model of the local behaviour. If the received updates are rendered directly, the resulting behaviour can be disjoint and unnatural. To overcome this problem, techniques are employed to smoothen the behaviour. These are known as convergence techniques. In the case of dead reckoning first order and cubic spline algorithms ...

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Section: Simulations and Resultsmentioning

confidence: 99%

A novel convergence algorithm for the hybrid strategy model packet reduction technique

Delaney¹,

McLoone²,

Ward³

2005

IEE Irish Signals and Systems Conference 2005

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“…To investigate this approach, four separate test courses were developed in the Torque game engine [9]. Several different tracks are considered in order to illustrate the effectiveness of the proposed method.…”

Section: Experimentationmentioning

confidence: 99%

Statistical Determination of Hybrid Threshold Parameters for Entity State Update Mechanisms in Distributed Interactive Applications

Marshall

McLoone

Delaney

et al. 2006

2006 Tenth IEEE International Symposium on Distributed Simulation and Real-Time Applications

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Collaboration within a Distributed Interactive Application (DIA) requires that a high level of consistency be maintained between remote hosts. However, this can require large amounts of network resources, which can negatively affect the scalability of the application, and also increase network latency. Predictive models, such as dead reckoning, provide a sufficient level of consistency, whilst reducing network requirements. Dead reckoning traditionally uses a spatial error threshold metric to operate. In previous work, it was shown how the use of the spatial threshold could result in potentially unbounded local absolute inconsistency. To remedy this, a novel time-space threshold was proposed, that placed bounds on local absolute inconsistency. However, use of the time-space threshold could result in unacceptably large spatial inconsistency. A hybrid approach that combined both error threshold measures was then shown to place bounds on both levels of inconsistency. However, choosing suitable threshold values for use within the hybrid scheme has been problematic, as no direct comparisons can be made between the two threshold metrics. In this paper, a novel comparison scheme is proposed. Under this approach, an error threshold look-up table is generated, based on entity speed and equivalent inconsistency measures. Using this look-up table, it is shown how the performance of comparable thresholds is equal on average, from the point of view of network packet generation. These error thresholds are then employed in a hybrid threshold scheme, which is shown to improve overall consistency in comparison to the previous solution of simply using numerically equal threshold values.

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“…A mathematical derivation of the relationship between path curvature and absolute consistency is determined, thus improving our understanding of the issue in question. Experimental live trials across the Internet are conducted using an industry standard games engine called Torque [4]. The obtained results clearly illustrate the effects of curvature on the various error threshold metrics used with the dead reckoning entity update mechanism.…”

Section: Introductionmentioning

confidence: 97%

Exploring the Effect of Curvature on the Consistency of Dead Reckoned Paths for Different Error Threshold Metrics

Marshall

McLoone

Roberts³

et al. 2006

2006 Tenth IEEE International Symposium on Distributed Simulation and Real-Time Applications

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A realistic distributed interactive application testbed for static and dynamic entity state data acquisition

Cited by 5 publications

References 4 publications

A novel convergence algorithm for the hybrid strategy model packet reduction technique

A novel convergence algorithm for the hybrid strategy model packet reduction technique

Statistical Determination of Hybrid Threshold Parameters for Entity State Update Mechanisms in Distributed Interactive Applications

Exploring the Effect of Curvature on the Consistency of Dead Reckoned Paths for Different Error Threshold Metrics

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