muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) (10/24/90)
Here are some observations that were triggered on reading a simulation about bird flight on one of the BBoards (Alife ?). ---- It seems that some flock of birds fly in random formation and then suddenly converge together, and then continue almost in random flight and then again converge etc. I was puzzled about whether there were "leaders" in the flock that the other followed or whether the birds were just forced into the streamlines of the air ? If the birds were indeed following a few leaders it seemed to me that they would also have similar wing beating patterns. It is really an interesting question of whether birds (in flight) show intelligent behaviour or are just purely constrained by the physical laws of flight (wind streams etc). Any comments ?
jimf@idayton.field.intel.com (Jim Fister) (10/24/90)
muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) writes: > It seems that some flock of birds fly in random formation and >then suddenly converge together, and then continue almost in random flight >and then again converge etc. [stuff deleted 'cause of bandwitdh] >It is really an interesting question of whether >birds (in flight) show intelligent behaviour or are just purely constrained >by the physical laws of flight (wind streams etc). >Any comments ? Sure. My experience of watching birds (usually somewhat drunk sitting in a field) seems to say that birds just kinda' weave around in flight for fun. Who says a straight line is the best way to go? Anyway, the observations you've made could be a byproduct of many random patterns turning into one large one. Oh, nature programs always say that migratory birds exchange leadership roles while the rest of the flock drafts off of the leader. Less random there. Greetings from the rocking metropolis. JimF
feldy@kona.cs.ucla.edu (Bob Felderman) (10/25/90)
In article <1990Oct23.170118.27104@ecn.purdue.edu> muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) writes: > > Here are some observations that were triggered on reading a >simulation about bird flight on one of the BBoards (Alife ?). [...] >Any comments ? See the article "Flocks, Herds, and Schools: A Distributed Behavioral Model" by Craig Reynolds in ACM Computer Graphics, Vol. 21, No 4, July 1987 pp 25-34 (I think this is a siggraph proceedings). -- Bob Felderman feldy@cs.ucla.edu UCLA Computer Science ...!{rutgers,ucbvax}!cs.ucla.edu!feldy
mccool@dgp.toronto.edu (Michael McCool) (10/25/90)
jimf@idayton.field.intel.com (Jim Fister) writes: >muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) writes: >> It seems that some flock of birds fly in random formation and >>then suddenly converge together, and then continue almost in random flight >>and then again converge etc. [stuff deleted 'cause of bandwitdh] >>It is really an interesting question of whether >>birds (in flight) show intelligent behaviour or are just purely constrained >>by the physical laws of flight (wind streams etc). >>Any comments ? You might want to check out the work done in graphics on the animation of flocks, herd, schools (of fish), and other collective motion. I don't have any references handy, but you can ask a friendly neighbourhood graphics type or look through the last few years of Computer Graphics (the proceedings of the SIGGRAPH conference published in journal form). There is also an nice animation, whose name escapes me (BOY, I'm a LOT of help, aren't I?) which animated fish & birds. I seem to recall windstream has nothing to do with it; the collective behaviour is a result of the birds desire to "remain together" balanced against a desire to avoid collision with each other and objects. And of course, at least in the case of birds, a minimum speed may be necessary to remain airborne (ignoring hovering and soaring). Collective "goal-directed" behaviour, i.e. following a general path or going towards a point (tropism) is also a factor. Anyhow, good luck. Michael McCool@dgp.toronto.edu
n025fc@tamuts.tamu.edu (Kevin Weller) (10/26/90)
In article <1990Oct25.100748.2501@jarvis.csri.toronto.edu> mccool@dgp.toronto.edu (Michael McCool) writes: > ... > I seem to recall windstream has nothing to do with it; the collective behaviour > is a result of the birds desire to "remain together" balanced against a desire > to avoid collision with each other and objects. And of course, at least in the > case of birds, a minimum speed may be necessary to remain airborne (ignoring > hovering and soaring). Collective "goal-directed" > behaviour, i.e. following a general path or going towards a point (tropism) > is also a factor. > > Anyhow, good luck. > Michael McCool@dgp.toronto.edu Hmmm ... if my memory of zoology class is accurate (it's been a while), birds flying in an "inverted V" pattern do so for aerodynamic reasons. I don't know the physics behind it (yet), but the leader supposedly makes the flying easier on the rest of the flock if they remain in formation. The periodic changeoffs take place to give the original leader a (relative) rest while the new leader takes over the burden. A bird flying by itself must work harder to stay up, significantly harder on long-term (i.e., migration) flights. I will try to find a reference (in my zo book) if you want some real physics. -- Kev
G.Joly@ucl-cs.UUCP (10/26/90)
From: Gordon Joly <G.Joly@uk.ac.ucl.cs> > From: muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) > Here are some observations that were triggered on reading a > simulation about bird flight on one of the BBoards (Alife ?). [...] > It is really an interesting question of whether > birds (in flight) show intelligent behaviour or are just purely > constrained by the physical laws of flight (wind streams etc). > > Any comments ? I believe that birds fly with a purpose, just as ants and termites organize themsleves. Gordon Joly +44 71 387 7050 ext 3716 InterNet: G.Joly@cs.ucl.ac.uk UUCP: ...!uunet.uu.net!ucl-cs!G.Joly Computer Science, University College London, Gower Street, LONDON WC1E 6BT
sen@cl.bull.fr (sen) (10/26/90)
In article <1990Oct23.170118.27104@ecn.purdue.edu> muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) writes: > > Here are some observations that were triggered on reading a >simulation about bird flight on one of the BBoards (Alife ?). > >---- > It seems that some flock of birds fly in random formation and >then suddenly converge together, and then continue almost in random flight >and then again converge etc. I was puzzled about whether there were >"leaders" in the flock that the other followed or whether the birds were >just forced into the streamlines of the air ? If the birds were indeed >following a few leaders it seemed to me that they would also have similar >wing beating patterns. It is really an interesting question of whether >birds (in flight) show intelligent behaviour or are just purely constrained >by the physical laws of flight (wind streams etc). > >Any comments ? a interesting analogy. a school of fish swimming in a pond suddenly as if triggered by a controlling stimuli change direction. anybody watching a fish pond could find it. if there is a leader (the first fish) then their reaction time is near-zero. also how do they "watch" the leader - eyesight (?) or some other physical phenomenon unobserved. looking at the speed of reaction one would choose the latter (!!!). personally i am confused a bit on this. i am sorry for the digression but lookink at your theme i felt to give - siddhartha this example. -- ***e-mail: sen@cl.bull.fr----------------##-----SIDDHARTHA---SEN*************** voice-mail: (33) (1) 34.60.47.52 (res) ## snail-mail: F 7 1 D 5, BULL S.A. v-mail: (33)(1)34.60.47.52 ext 3911(off) ## 78340 Les Clayes sous Bois, FRANCE ****** LA VIE EST UNE TRANSITION ENTRE UNE INCERTITUDE ET UNE AUTRE !! *******
mccool@dgp.toronto.edu (Michael McCool) (10/27/90)
n025fc@tamuts.tamu.edu (Kevin Weller) writes: >Hmmm ... if my memory of zoology class is accurate (it's been a >while), birds flying in an "inverted V" pattern do so for aerodynamic >reasons. I don't know the physics behind it (yet), but the leader >supposedly makes the flying easier on the rest of the flock if they >remain in formation. The periodic changeoffs take place to give the >original leader a (relative) rest while the new leader takes over the >burden. A bird flying by itself must work harder to stay up, >significantly harder on long-term (i.e., migration) flights. I will >try to find a reference (in my zo book) if you want some real physics. >-- Kev Well, when we talk about emergent properties I thought we were talking about "flocking" behaviour, like masses of sparrows or crows wheeling as a "unit". This type of behaviour has been well simulated in computer graphics without taking air drag into account. The V shape IS more dependent on the physics of the situation, I think, than typical flocking behaviour. I feel that the V migration pattern falls under a different, more specialized and stereotypical type of behaviour. The most interesting collective behaviours to me are where the group acts like an "organism" and responds immediately and appropriately to its enviroment with seemingly no communication between members, and where the responses are varied to fit the environment; they can almost seem to be "intelligent" responses. Focussing on this type of behaviour also seems more in tune with the discussion in this group. Any sociologists out there? In what respect are related behaviours, i.e. voting patterns, emergent? Are there any socially emergent properties of groups of PEOPLE? Especially interesting behaviours are those that are unplanned, and even uncommunicated, but arise as the result of individual descisions and adaptations to what others are doing (or are expected to be doing). What springs to mind are pricing strategies in ogliopolies, a la Galbraith's "The New Industrial State": nobody communicates, but everyone has such a good model of everyone else that prices end up being stable. Each company predicts what the other is going to do, and trys to avoid a price war which would be detrimental to all parties. The actual price chosen ACTS, and can be treated as, the result of collusion, even though that is not how it is arrived at. How does this relate to AI? Well, the question is, can a society of autonomous units be treated as an organism even if no *explicit* communication channels exist? What are the types of communication between subunits that can lead to goal-directed behaviour? Is only interaction through actions taken in the common environment enough? And how do the goals of the subunits become translated into the goals of the collective body? Comments? Flames? Michael McCool@dgp.toronto.edu
gt8554a@prism.gatech.EDU (JANAKIRAMAN,SHANKER) (10/27/90)
I remember one of my professors mentioning this in Fluid Mechanics
class. As I remember, there are no fixed leaders. The leading
position is occupied by different birds in turns. The overall formation
of the flock is in such a way that the energy consumed is minimised.
I guess this pertains to birds in migratory flights, as I have seen
birds flying in random many a times in the city skyline, as mentioned.
I leave it for the better informed AI people to speculate about
emergence.
QUIT
--
JANAKIRAMAN,SHANKER
Georgia Institute of Technology, Atlanta Georgia, 30332
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