University of Twente Student Theses


Flock together : an analysis of starling swarm intelligence in the StarDisplay model

Opheusden, L.M.E. van (2014) Flock together : an analysis of starling swarm intelligence in the StarDisplay model.

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Abstract:Flocks of starlings have been known to show intricate aerial displays called murmurations. In the article "Self-organized aerial displays of thousands of starlings: a model", that was published in Behavioral Ecology as of the 11th of October 2010, H. Hildenbrandt, C. Carere and C.K. Hemelrijk explain the typical swarm behavior as the effect of self organization. They present the StarDisplay model, that can be used to describe the roosting behavior of a flock of starlings in terms of swarm intelligence. The model defines simple rules for the birds, in an attempt to mimic real life ight behavior. In this report, the effects of these rules are investigated. We have found three problems with the StarDisplay model and propose adaptations to solve these. The model uses Tait-Bryan angles to define the orientation of a bird in space. If the orientation is vertical, the heading and banking axes become parallel and the system loses one degree of freedom. This is solved by adding a driven gimbal or by using a different representation for the orientation. For this model, the Tait-Bryan angles suffice, so no adaptation is proposed. The updating mechanism for the interaction range lacks a lower boundary, but a radius can not be negative. Moreover, the radius does not stabilize when the desired number of partners is reached, but instead decreases. The absence of a lower boundary can be disregarded if the time step is sufficiently small. The limit radius is fixed with a minor alteration to the interaction range control. The banking angle control causes the birds to spin violently, instead of gradually banking toward their goal. In addition, the model makes use of infinite accelerations, which disagrees is physically impossible. Newton's second law for rotational motion is used to rewrite the updating mechanism. The proposed adaptations to the StarDisplay do not change the behavior of the model in the tested situation. They are an improvement because they impose boundaries and prevent discontinuities. Further research is needed to verify that the study done in the article can be reproduced using the adapted StarDisplay model.
Item Type:Essay (Bachelor)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:31 mathematics
Programme:Applied Mathematics BSc (56965)
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