Emergence, networks, threshold phenomena, and entity formation

[Russ Abbott]

In a recent discussion about emergence I wrote the following (somewhat edited).

Emergence is what happens when components of the emergent entity act in such a way as to bring about the existence and persistence of that entity. For example, when "boids" follow their local flying rules, they create (implement) a flock. It's not mysterious. We know how it works.

That's all emergence is: coordinated or consistent actions among a number of elements that result in the formation and persistence of some aggregate entity or phenomenon. The "coordination" doesn't have to be top-down. In flocking, for example, there is local (or networked) coordination. The flying rules for on each boid depend on that boid seeing neighboring boids. One can even say that there is some overall coordination: all the boids follow the same rules.

It's worth pointing out that in biological and social emergent entities, the components may come and go while the entity persists. What emerges is a pattern of activities, not a physical thing. That's one of the reasons people get confused. (And that's why subvenience is not particularly useful in these cases.)

But if you just think about emergence as a persistent pattern of activities, that pretty much takes care of it. It's the fact that the pattern persists that matters, not the elements that are acting to produce the pattern.

One of the more interesting issues in complex systems is the formation of entities --. that "boid attraction" creates flocks is a simple example.

With that in mind, it might be interesting to do some experiments. For example, How dense does a collection of boids have to be for a flock to form?  Or more to the point, if the boids are confined to a limited, e.g., toroidal, space, how does their initial density determine the rate at which the flock forms? What about the other parameters such as the distance each individual boid can see (that is, which boids become neighbors) and the velocity at which the boids are moving compared to the "attraction" they have on each other? This is like gravity and asking whether two passing bodies will form an orbiting system or simply affect each other's velocities as they pass and separate.

What if the environment included obstacles that the boids had to avoid. Some of those obstacles could presumably break up a flock. So how do flock formation and flock disintegration interact? There might be other disintegration forces such as boids moving a bit more randomly.

How do these results relate to similar results in networks such as network formation and connectivity, etc.?

Do any "self-organized criticality" effects appear?

Does anyone know whether experiments of this sort have been done, and if so, what the results were?

Having written this down, these feel like questions that should have been asked a decade ago. But perhaps there might still be something there. Entity formation is an open and important issue. Perhaps experiments of this sort might shed some light on it

-- Russ


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[Ted Carmichael]

Hi, Russ.  Thanks for the post.  It's always interesting to think about these things.

Offhand, I think the most relevant factors would be the number of interactions (how often one boid affects another) and the strength of those interactions (to what degree one boid affects another, and in what ways).  

In a torus, I believe two boids will always - eventually - flock, regardless of how seldom or weak the interactions are.  (Of course, this assumes that the interactions will occur at some point and that they are formulated to induce flocking ... probably it would be possible that their path/speed was such that they reach a point where they stop interacting, even in a torus.)

It would also depend on how you define a 'flock,' I suppose.  Probably based somehow on the rules for moving closer or farther apart.

I think this way would simplify things.  I'd guess the boids would keep getting closer together until the number of "move apart" interactions approximately equals the number of "move closer" interactions.  This would be the equilibrium point - assuming both types of interactions are equal in their degree of effect).  Probably the rate of movement towards a flock would change over time as the % of interactions gets closer to the equilibrium point.  I reckon the speed of change in these percentages would decrease as you approach the equilibrium point.  

Anyway, it should be easy to test ... if all that is correct, you just have to count the interactions of each type over time, and see when (if) they begin to fluctuate around some equilibrium point.

How does that sound?

Cheers,

Ted

On Sun, Sep 6, 2009 at 5:37 PM, Russ Abbott <[hidden email]> wrote:

In a recent discussion about emergence I wrote the following (somewhat edited).

Emergence is what happens when components of the emergent entity act in such a way as to bring about the existence and persistence of that entity. For example, when "boids" follow their local flying rules, they create (implement) a flock. It's not mysterious. We know how it works.

That's all emergence is: coordinated or consistent actions among a number of elements that result in the formation and persistence of some aggregate entity or phenomenon. The "coordination" doesn't have to be top-down. In flocking, for example, there is local (or networked) coordination. The flying rules for on each boid depend on that boid seeing neighboring boids. One can even say that there is some overall coordination: all the boids follow the same rules.

It's worth pointing out that in biological and social emergent entities, the components may come and go while the entity persists. What emerges is a pattern of activities, not a physical thing. That's one of the reasons people get confused. (And that's why subvenience is not particularly useful in these cases.)

But if you just think about emergence as a persistent pattern of activities, that pretty much takes care of it. It's the fact that the pattern persists that matters, not the elements that are acting to produce the pattern.

One of the more interesting issues in complex systems is the formation of entities --. that "boid attraction" creates flocks is a simple example.

With that in mind, it might be interesting to do some experiments. For example, How dense does a collection of boids have to be for a flock to form?  Or more to the point, if the boids are confined to a limited, e.g., toroidal, space, how does their initial density determine the rate at which the flock forms? What about the other parameters such as the distance each individual boid can see (that is, which boids become neighbors) and the velocity at which the boids are moving compared to the "attraction" they have on each other? This is like gravity and asking whether two passing bodies will form an orbiting system or simply affect each other's velocities as they pass and separate.

What if the environment included obstacles that the boids had to avoid. Some of those obstacles could presumably break up a flock. So how do flock formation and flock disintegration interact? There might be other disintegration forces such as boids moving a bit more randomly.

How do these results relate to similar results in networks such as network formation and connectivity, etc.?

Do any "self-organized criticality" effects appear?

Does anyone know whether experiments of this sort have been done, and if so, what the results were?

Having written this down, these feel like questions that should have been asked a decade ago. But perhaps there might still be something there. Entity formation is an open and important issue. Perhaps experiments of this sort might shed some light on it

-- Russ

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org

[Russ Abbott]

It sounds great if you have the time to do the experiments. :) 

It's an interesting observation that two boids in a torus will eventually flock. Suppose that they started off moving both orthogonally and out of phase. There is no reason for that to change since they are never in each other's neighborhood.

But if you add some random drift effects, then presumably they will eventually begin to affect each other and over time move closer and closer together until they become a flock.

By the way, I would define a flock as a collection of boids that form a persistently fully connected network where the boids are the nodes, the links are between boids that are in each other's neighborhoods, and persistently means that the entire collection is always fully connected.

Given that definition, given a flock will it eventually settle into a fixed network, i.e., with no link changes?  It's conceivable that a flock may remain a flock even though there are continuing internal link changes. So the question is will every flock eventually find a fixed network configuration.  Since by my definition of a flock, the entire collection will always be fully connected, then it would seem that internal forces will pull it into a fixed (minimal energy) state.

Someone must have proved some results along those lines already.

-- Russ

On Sun, Sep 6, 2009 at 3:48 PM, Ted Carmichael <[hidden email]> wrote:

Hi, Russ.  Thanks for the post.  It's always interesting to think about these things.

Offhand, I think the most relevant factors would be the number of interactions (how often one boid affects another) and the strength of those interactions (to what degree one boid affects another, and in what ways).  

In a torus, I believe two boids will always - eventually - flock, regardless of how seldom or weak the interactions are.  (Of course, this assumes that the interactions will occur at some point and that they are formulated to induce flocking ... probably it would be possible that their path/speed was such that they reach a point where they stop interacting, even in a torus.)

It would also depend on how you define a 'flock,' I suppose.  Probably based somehow on the rules for moving closer or farther apart.

I think this way would simplify things.  I'd guess the boids would keep getting closer together until the number of "move apart" interactions approximately equals the number of "move closer" interactions.  This would be the equilibrium point - assuming both types of interactions are equal in their degree of effect).  Probably the rate of movement towards a flock would change over time as the % of interactions gets closer to the equilibrium point.  I reckon the speed of change in these percentages would decrease as you approach the equilibrium point.  

Anyway, it should be easy to test ... if all that is correct, you just have to count the interactions of each type over time, and see when (if) they begin to fluctuate around some equilibrium point.

How does that sound?

Cheers,

Ted

On Sun, Sep 6, 2009 at 5:37 PM, Russ Abbott <[hidden email]> wrote:

In a recent discussion about emergence I wrote the following (somewhat edited).

Emergence is what happens when components of the emergent entity act in such a way as to bring about the existence and persistence of that entity. For example, when "boids" follow their local flying rules, they create (implement) a flock. It's not mysterious. We know how it works.

That's all emergence is: coordinated or consistent actions among a number of elements that result in the formation and persistence of some aggregate entity or phenomenon. The "coordination" doesn't have to be top-down. In flocking, for example, there is local (or networked) coordination. The flying rules for on each boid depend on that boid seeing neighboring boids. One can even say that there is some overall coordination: all the boids follow the same rules.

It's worth pointing out that in biological and social emergent entities, the components may come and go while the entity persists. What emerges is a pattern of activities, not a physical thing. That's one of the reasons people get confused. (And that's why subvenience is not particularly useful in these cases.)

But if you just think about emergence as a persistent pattern of activities, that pretty much takes care of it. It's the fact that the pattern persists that matters, not the elements that are acting to produce the pattern.

One of the more interesting issues in complex systems is the formation of entities --. that "boid attraction" creates flocks is a simple example.

With that in mind, it might be interesting to do some experiments. For example, How dense does a collection of boids have to be for a flock to form?  Or more to the point, if the boids are confined to a limited, e.g., toroidal, space, how does their initial density determine the rate at which the flock forms? What about the other parameters such as the distance each individual boid can see (that is, which boids become neighbors) and the velocity at which the boids are moving compared to the "attraction" they have on each other? This is like gravity and asking whether two passing bodies will form an orbiting system or simply affect each other's velocities as they pass and separate.

What if the environment included obstacles that the boids had to avoid. Some of those obstacles could presumably break up a flock. So how do flock formation and flock disintegration interact? There might be other disintegration forces such as boids moving a bit more randomly.

How do these results relate to similar results in networks such as network formation and connectivity, etc.?

Do any "self-organized criticality" effects appear?

Does anyone know whether experiments of this sort have been done, and if so, what the results were?

Having written this down, these feel like questions that should have been asked a decade ago. But perhaps there might still be something there. Entity formation is an open and important issue. Perhaps experiments of this sort might shed some light on it

-- Russ

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org

[Ted Carmichael]

The two ideas do seem to be at odds.  I think of the "persistence" of emergent features as being caused by basins of attraction.  The strange attractors of a system subtly encourage all the agents of that system towards stability, through (perhaps) the efficient use of energy.

But that would seem to be in line with increased entropy over time, and it's clear that there are local and/or temporary decreases in entropy at the heart of complex systems.  Perhaps these are explained by perturbations in the system, either exogenous ones (like the amount of energy from the sun changing on daily, yearly, and decadal scales) or endogenous ones ... feedback from the system that is changing that system at a different scale than what produces the emergent property.

In Hugh's peloton example, the bicyclists form these groups, but they also get tired over time.  Eventually, they all stop riding, and the emergent property dissipates.  Or an ant colony self-organizes to find a food source ... when the food source runs out, this is a perturbation on the system, and they have to reorganize around a different food source.

So maybe an emergent feature could be thought of as "temporary persistence."  And free energy from the sun ensures a continual supply of perturbations on the earth.

Probably two components would be enough to produce an emergent effect, but it wouldn't be a very interesting one.

-Ted

On Mon, Sep 7, 2009 at 12:28 PM, Mirsad Hadzikadic <[hidden email]> wrote:

Now, I am somewhat confused.  To me, persistence refers to a set of features that continue to be perceived or exhibited, despite the “rejuvenation” of the individual elements of the body that creates it.  Emergence, somehow, indicates an uncertain, possibly unexpected, outcome.  Also, persistence somehow assumes a long lasting pattern, while ( to me) emergence may be short lived or even a one-time event.

How many components would there have to be for a pattern/persistence to be noted?  Does it depend on the eye of the beholder?

Mirsad

On 9/6/09 5:37 PM, "Russ Abbott" <Russ.Abbott@...> wrote:

In a recent discussion about emergence I wrote the following (somewhat edited).

Emergence is what happens when components of the emergent entity act in such a way as to bring about the existence and persistence of that entity. For example, when "boids" follow their local flying rules, they create (implement) a flock. It's not mysterious. We know how it works.

That's all emergence is: coordinated or consistent actions among a number of elements that result in the formation and persistence of some aggregate entity or phenomenon. The "coordination" doesn't have to be top-down. In flocking, for example, there is local (or networked) coordination. The flying rules for on each boid depend on that boid seeing neighboring boids. One can even say that there is some overall coordination: all the boids follow the same rules.

It's worth pointing out that in biological and social emergent entities, the components may come and go while the entity persists. What emerges is a pattern of activities, not a physical thing. That's one of the reasons people get confused. (And that's why subvenience is not particularly useful in these cases.)

But if you just think about emergence as a persistent pattern of activities, that pretty much takes care of it. It's the fact that the pattern persists that matters, not the elements that are acting to produce the pattern.

One of the more interesting issues in complex systems is the formation of entities --. that "boid attraction" creates flocks is a simple example.

With that in mind, it might be interesting to do some experiments. For example, How dense does a collection of boids have to be for a flock to form?  Or more to the point, if the boids are confined to a limited, e.g., toroidal, space, how does their initial density determine the rate at which the flock forms? What about the other parameters such as the distance each individual boid can see (that is, which boids become neighbors) and the velocity at which the boids are moving compared to the "attraction" they have on each other? This is like gravity and asking whether two passing bodies will form an orbiting system or simply affect each other's velocities as they pass and separate.

What if the environment included obstacles that the boids had to avoid. Some of those obstacles could presumably break up a flock. So how do flock formation and flock disintegration interact? There might be other disintegration forces such as boids moving a bit more randomly.

How do these results relate to similar results in networks such as network formation and connectivity, etc.?

Do any "self-organized criticality" effects appear?

Does anyone know whether experiments of this sort have been done, and if so, what the results were?

Having written this down, these feel like questions that should have been asked a decade ago. But perhaps there might still be something there. Entity formation is an open and important issue. Perhaps experiments of this sort might shed some light on it

-- Russ

--
Mirsad Hadzikadic, Ph.D.
Director, North Carolina Complex Systems Institute
Department of Software and Information Systems
College of Computing and Informatics
343A Woodward Hall
The University of North Carolina at Charlotte
Charlotte, NC 28223
USA
Work: 704-687-8643
Cell: 704-340-0062
Email: mirsad@...
Web: cciweb.uncc.edu/~mirsad/

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org