Nabin K. Malakar, Ph.D.

NASA JPL
I am a computational physicist working on societal applications of machine-learning techniques.

Research Links

My research interests span multi-disciplinary fields involving Societal applications of Machine Learning, Decision-theoretic approach to automated Experimental Design, Bayesian statistical data analysis and signal processing.

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Interested about the picture? Autonomous experimental design allows us to answer the question of where to take the measurements. More about it is here...

Hobbies

I addition to the research, I also like to hike, bike, read and play with water color.

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Showing posts with label statistical. Show all posts
Showing posts with label statistical. Show all posts

Monday, March 12, 2012

Grackles fly, merge and cluster in North TX

The Grackle(s) look like crows with extra feathers, little longer.
With the arrival of the Spring, these guys migrate through North Texas. They travel in huge numbers as a group, and can be source of nuisance to some [Link].

As a physicist, it would be interesting to learn about their flocking behavior.
There are statistical physics papers about such behaviors... and Physics Today had a cover story about it 2/3 years(?) ago... Please point the article if you could.


In this post, I present you the flocking swarm of Grackles as they settle down for the night. Please feel free to share.


Tuesday, July 20, 2010

Collective Behavior in Animals

Feel like yawning? Look around, someone near you might also be yawning!

The so called collective behavior such as yawning might be an urban myth but a recent studies have attempted to model such collective behavior. The modal system they considered consists of an example of collective behavior of cows. Such theories have not been tested it in the real cows, however one should not be surprised to see such studies to be verified in near future.

In a recent work, published in arxiv,  Sun et. al. study the collective behavior of animals such as cows.  Animals are coupled oscillators. They simply model the cow as coupled oscillator. By considering the discrete states of such animals and by considering such couplings, they study the collective decision bearing of such system.
Specifically, they consider three states of cows: standing, sitting and grazing; say "1", "2" and "3" just for sake of easy symbolization. By coupling the states, they assume that behavior of one is going affect the behavior of nearby ones. So, there is more tendency of uniform state such as 1,1,1,1,1 than 1,2,3,2,1 or 1,2,1,2,3. However, for larger cow population there can be some nice oscillatory behavior between the stable states.
The paper is interesting! Have a look.
Ref:
http://arxiv.org/abs/1005.1381
http://www.technologyreview.com/blog/arxiv/25171/


Acknowledgements are due to the first author for suggests in the draft version of the post and allowing to use the figures.

Fig: Coupled cows.

On the lighter side:
One can see the influence of "spherical cow" on the coupling diagrams. See Jackson, J.D. Third Edition Ch3 problem#15.