Improving the Performance of Partitioning Methods for Crowd Simulations

Abstract

Simulating the realistic behavior of large crowds of autonomous agents is still a challenge for the computer graphics community. In order to handle large crowds, some scalable architectures have been proposed. Nevertheless, the effective use of distributed systems requires the use of partitioning methods that can properly assign different sets of agents to the existing distributed resources.In this paper, we propose the improvement of the partitioning method for distributed crowd simulations by using irregular shape regions. Concretely, we propose the partition of the virtual world using convex hulls. The performance evaluation results show that the Convex Hull method outperforms the rest of the considered methods in terms of both fitness function values and execution times, regardless of the movement pattern followed by the agents. These results show that the shape of the regions in the partition can improve the performance of the partitioning method, rather than the heuristic method used.

Workload balancing in distributed crowd simulations: the partitioning method

“…The QHull method provides a good performance for different movement patterns with respect to other existing methods [14]. However, we have detected eventual saturations of some servers in real systems during some simulations when using this partitioning method, particularly for those movement patterns that generate the highest workload (the sdown movement pattern, a situation where there is a single exit in a structured maze and all the agents should evacuate the maze).…”

“…Finally, ω 1 and ω 2 are weighting factors between 0 and 1 that can be tuned to change how the partitions are evaluated. We used H (P ) (with 0.6 and 0.4 for ω 1 and ω 2 values, respectively) as the global fitness function for measuring the quality of the partitions provided by the QHull method as well as other partitioning method evaluated as reference values [14]. The reason for choosing these values is on one hand that a significant value for ω 2 is needed for avoiding the saturation of any server [7].…”

“…The autonomous agents must try to escape from the world as soon as possible. For this scenario, we have used the same well-known movement patterns considered for evaluating the QHull method [14].…”

“…In this paper, we propose to enhance the QHull partitioning method proposed in [14], ensuring that none of the server reaches saturation. In order to achieve this goal, we have modified that method by adding a workload balancing phase where servers reassigns agents to servers using a criterion of distance.…”

“…However, these and other region-based partitioning methods [8,9,16] add a significant overhead to the system. In order to reduce this overhead, we proposed the use of irregular shape regions (convex hulls) for solving the partitioning problem [14]. The performance of the method based on convex hulls is higher in terms of both fitness function values and execution times, but the usefulness of this method for real distributed systems is limited by the saturation of a few severs.…”