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Tuesday, October 19, 2010

The Human Swarm

What is the world population? A quick Google search turns up one estimate of... 6.69 billion around 2008. (6,875,900,000 from a Wiki for a more current figure.) This is a huge figure. Understandably, the world's a big place. But just try to conceptualize that for a minute. The population of New York City is just above 8 million. Larger still is Tokyo with somewhere around 35 million. (Both from Wiki entries) The world population in 'quantities of New York City' would be ~859. Or  perhaps ~196 Tokyos.

So there are a lot of us. How many people do you really encounter in a day though? 50? 100? Depends on your line of work or study I guess. Heres an interesting concept though: the six degrees experiment. This study goes on to say that everyone in the world is no more than 6 "social links" away from anyone else. Pretty wild. But take that with a grain of salt, as it doesn't necessarily hold up everywhere... but consider the statement it makes. We're all interconnected. Most everyone will agree with this statement in some form or another.

So there are a lot of us, and we're all connected. So what? This concept starts to set into motion the idea that with this interconnectedness, we start to coordinate our actions, and on a large scale too just because there are so many of us. We can collaborate and share and interact in a big way in this age. In sticking with the earlier examples of swarms, is there any behavior that society exhibits as a whole that may be considered emergent? (Hit up my course research page for more information on this particular idea. :) Heres a thought: Wikipedia. I've provided links to different articles all over this blog. How is it organized? Who contributes? (Do the terms "decentralized" and "self-organized" apply here?)

So, as it turns out, groups of humans can be organized into swarms of different sizes. Each behaves in its own way depending on situation, group composition, etc. In one of the links in the first entry on this blog, there is an NPR discussion on a book concerning some of the swarm characteristics of human networks. (I'd recommend this book, even, for a light, entertaining read concerning the subject.) The author lists some interesting rules that might help an individual act in a swarm (group) of humans:

  • "If you want to give yourself the best chance of choosing the very best option in a situation [that] doesn't allow you to go back to the options you have rejected, look at 37 percent of those available, then choose the next one that is better than any of them. This will give you a 1 in 3 chance of finding the best option, and a very high chance of finding one in the top few percent. [...]" (Fisher, 2009, p. 168)
  • "If you are in a crowd in a dangerous situation, use a mixed strategy for escape; follow the crowd 60 percent of the time, and spend the other 40 percent searching out escape routes on your own." (Fisher, 2009, p. 168)
  • "When planning a complicated road trip across a city, build in as many right turns as possible (or left turns if you happen to be in a country with left-hand drive." (Fisher, 2009, p. 169)
... incidentally, UPS follows this last rule when planning routes. (Various, heres one source

More fun links:
If you like this topic but aren't into humans (Robot Swarms):

A directory of resources on the subject:

Some weighty reading if the subject really interests you:
New Models for Crowd Dynamics and Control:

Particle swarm optimization:

Bibliographical Info:
Fisher, Len. (2009). The Perfect Swarm. New York: Basic Books.

Tuesday, October 12, 2010

Boids! (Its a boid, its a plane, its...)

Lets kick things off with a little video. The movements of the glob in the cube thing are almost reminiscent of... a school of fish or perhaps a flock of birds. (Get someone with a stereotypical New York accent to pronounce that last part for great effect. ;)

What you're witnessing is the interaction of a group of small entities known as Boids. Boids themselves aren't very smart or capable, but in groups they can exhibit some interesting qualities. These interesting qualities, or behaviors are known as an emergent behavior. (Another way to describe how they act is saying they exhibit flocking behavior.) Here are some interesting points about these boid things...
  • How do they avoid hitting each other?
  • How do they stay together as one group?
  • How do they avoid obstacles? 
Regardless, they're definitely fun to watch. An arena where you might have seen this sort of thing before aside from nature might be... video games. Think for a minute (if you play games) and see if you can recall seeing this sort of thing in any games you might have played. Its more common than people really realize. Particle effects, opponent AI (... and those opponents cooperating against you), etc... the list is longer than one first thinks.

Here are some fun links to explore until next time. :)

A flash site on other examples of emergence:

A wiki article on the Game of Life:'s_Game_of_Life
... and an implementation:

... and oh yeah, I said I was going to show some ways swarm intelligence relates directly to us as humans. Next time!

Tuesday, October 5, 2010

First things first: What is it?

Swarm Intelligence. It kind of has a feeling of magnitude, doesn't it? Its one of those terms you can drop in the middle of an explanation that kind of sticks out. But... what exactly is it though? The title is descriptive enough, but can you think of examples? I'd be willing to bet you've had at least a handful of encounters with it already.

Here it is: "Swarm Intelligence is a term describing the decentralized, self-organized behavior of systems composed of many individuals that are natural or artificial." Definitely a mouthful.

Maybe some examples would help. Ever seen a bee? How about an ant? I don't think you'd consider the actions of either as very intelligent. They seem to move around pretty randomly, usually -- as one would think -- in search of food or something similar. Curiously enough, though, they seem to be able to coordinate their efforts well enough to build hives of some sort, find food for their colonies, defend their home, etc.. If they were all just doing random things, how would any of that be possible?

You might think "Ooooh, ants and bees. How does this relate to anything?" Do a Google search for Locusts and you're likely to hit at least a dozen articles describing how some swarm somewhere is completely destroying our food sources. Suddenly this is a little more serious. Hm. Swarm Intelligence might be a little more pervasive than one first thinks. Schools of fish, herds of robots even... how about humans? Group decision making? Aha, theres something that hits us all. More on all of these later of course. :)

Here are some interesting tidbits to read over (or listen to) in the mean time:

(Audio) The Intelligence of crowds in 'The Perfect Swarm':

(Text) A wiki style collection of interesting applications and where else one might find swarms:

(Text) ...and for a bit of general knowledge concerning SI: