voronoi@school: urban lab Laboratory Topic 5: Allocating Resources to City Parks in Berkeley

voronoi in urban paper OBEUS: Object-Based Environment for Urban Simulations

a glimpse to Spatial Tessellations: Concepts and Applications of Voronoi Diagrams (Second Edition) by Atsuyuki Okabe, et.al With a Foreword by David G. Kendall
Chichester: John Wiley, 2000

again, it always start with something designed. here three kinds of randomness according to wolfram

• randomness from environment, this is like considering how random movement of a boat in the ocean. the randomness of boat movement are apparently from the randomness of sea surface movement.
• randomness from initial condition, which is like dice rolling, or driving car in a bumpy road. the bumpiness is already there which cause the randomness of car moving on top of it.
• intrinsic randomness, which acclaimed as the only pure random

the point is that all randomness still start with things, though wolfram told that intrinsic randomness could emerge from very simple rule and very simple initial conditions. still there should be something at start.

so the self-referentiality make herself a point again. something should come from something else. every outcome should have input beforehand.

as much as the idea of co-evolution which i would like to be able to interpret from HIllier's word that i adore so much "configuration of space influence and can be influenced by configuration of people" should there be a confirm start, would it be people first or space first?

the observer role, this is even more difficult to decide. in doing this experiment, shall i put myself as an architect who understand the relation between these two configurations, or shall i blind myself from knowing and just say that perhaps both exists at the same time from the very beginning and then evolve into an identified scheme?

the first scenario is that when we put ourselves as architect, do we see people first or space first isnt it entirely a subjective choice? in the emergent of walking path on a square garden in a busy city block, which comes first i guess is not important since the context is very same to that wolfram explanation of second kind of randomness. it all depend on initial condition, a chaos theory thing. the pedestrian routes were there, fixed in their relation to themselves. the garden also there, fixed relation to that routes. there's nothing that couldn't be anticipated would come out as the Occupational Pattern of walking path in that garden.

i'm very much suspect that p wants the second scenario. i will agree but surely want to be acknowledged as the one who done it, that i designed the very simple rules, very simple initial conditions and so on.

http://exchange.manifold.net/manifold/manuals/5_userman/mfd50Transform__Voronoi_Operators.htm



http://exchange.manifold.net/manifold/manuals/5_userman/mfd50Transform__Triangulation.htm

hi choesnah,
yes, I did work with Voronoi diagrams and Delaunay triangulations
(actually delaunay tetrahedralisations, since it was 3d). Unfortunatelly,
even if I did write a paper on my work it did not talk that much in detail
about Voronoi diagrams. You can anyway find it at:
http://www.generativeart.com/ga2001_PDF/miranda.pdf
it seems anyway not to be working that well so you can instead try:
http://www.interactiveinstitute.se/sensen/PabloGA2001.pdf
and
http://www.interactiveinstitute.se/sensen/Pablo_desc.pdf

for more information on voronoi diagrams there are quite a few applets
around in which the algorithms are explained. I used one that was an
Incremental algorithm. It basically goes like this:

(this is for 2D, for 3d, substitute where it says triangles by tetras, and
circles by spheres (and three points by four points).

you have points in space.

1.make three points that form a triangle that includes all the other points
(usually this is done by drawing a huge triangle, basically the biggest
one you can build. It will for shure include all your points.


2.calculate the circle that circunscribes the triangle (there are formulas
lying around in the net for this).

3. take any point (of the ones you had) and find out in which circle it lays
(if this is the first time, that is easy, since it will lie in the huge
triangle and therefore circle you defined).

4 make triangles form the new point to the three points that define the
circle it is in, and for each of the new triangles calculate their
circunscribing circle.

5.iterate for any next point from step 3.

You will obviously run through all the points untill you are done with
them. The triangulation you have will be one in which there are no points
that are inside circles defined by any other three points (Delaunay
triangulation). The dual of the triangulation is the Voronoi diagram.

Good link:
http://www.ics.uci.edu/~eppstein/junkyard/nn.html

the algorithm I used was some code I adapted from Bowyer-Watson's
Incremental algorithm. The page I found it in does not seem to work
anymore.

Do you know any C/C++ or Java? that will make it easier since most of the
algorithms you find around are writen in those languages (there are some
bits of Fortran code lying around, if you know Fortran).

There is somethin called Qhull (it is an open source code for calculation
of convex hulls, delaunay triangulations and voronoi diagrams to n
dimensions!) but I found difficult to find my way around it and the
documentation.

Often nice people leaves the code for their applets accessible in their
pages. Check in the html code the tag "code" for the applet (it will say
something.something.class or something.class check in your browser for a
file in the same directory called the same, but instead of class write
.java, you may be lucky and get the code! (if you know C++ it will be
quite easy to translate the code).

The best thing to do is to give yourself a couple of weeks to surf, colect
info and analise the algorithms.

Good luck and say hello to Paul and Christian.

Pablo

- - - - - - - - - -

I think that what you are discussing here is the status of the observer, and
of course in a simulation there is this problem with getting the various
levels of observation from local to global sorted out, so that as in starlogo
we can be explicit about it.

this problem doesnt occur in the world since the status of the observer is an
emergent property of the evolution of perceptive structures. I dont have a
problem with the idea that there is some circularity involved, structural
coupling has to be reflexive - its the old boot strap problem - the need for
a primum mobilus (first mover) which seems a problem when considering
classical machines, but pulling yourself up by your own bootstraps is exactly
what life has to do. maturana is very careful to avoid tautology, but his
circular way of reasoning is needed so as not to go into infinite regress.

I dont know who we were talking about, but of course i would always disagree
about the necessity for a designer. thats what the blind watchmaker is all
about. the very idea of a "designer" is anathema in the context of evolution.
of course as i said above, in the context of simulation we have to design the
system, so what we have to do is
1. be very explicit about the stuff that is designed and define the axioms
very carefully
2. try to get away with the minimum of arbitrary rules
3. be explicit about the different sorts of observers in the system


self organisation does i guess depend on certain space time physics stuff.
there is a new book out which i read about (cant remember name of course)
which explains that nature has many underlying regularities based on least
energy lattices and standard valencies among atoms and molecules. so when an
organism develops bilateral symmetry or segmentation it is not some one off
lucky chance at all, but an inescapable outcome of those underlying laws of
form.

if we lived in a universe where pi was an integer, then presumably we would
find different regularities emerging.

p

circles




delaunay




edges




voronoi edges




voronoi

next move:

• formal form of intelligibility


• voronoi algo for OP


• figure out Wolfram's randomness-initial condition problem

i think alot about self-referential/circularity in the nature of design (remember when we talk about it last time, where we ended with acknowledging the role of designer? at least i did) i mean, somebody (forgot the name) has tried to prove that what maturana talks about isn't tautology, while the man himself clearly stated that self referentiality is the essence of his theory. organism's metabolism and reproductivity, are all about circularity.

i remember read from peter bentley in his digital biology, that "a universe is made from set of rules that define outcomes... at least one of the rules must be define in terms of another universe"(p.17)

in p.15 he wrote "the rule tells us that every outcome depends on something" (IF something THEN outcome) and his example of the universe of sound:

p.18 "To us, we can see that sounds are generated from vibrations of our molecules in our universe. so the rules defining the universe of sound are defined with respect to another universe: our own... to us they appear to be spontaneous and without explanation. to an observer (my emphasis, we know an observer exists outside the observed), our interference patterns (between sound an ears) are caused by their photons (sound) interacting with ours (our photons).

the most interesting pages are 16-17.

if i read bentley and maturana together, thus i'll get:
1. an observer, and the observed and explanation of observation
2. an observer is not at all part of/belong to the observed in "universe term" (universe is, look up to what he says in p.17. + he also says in p.16, no rules means a condition which not allow the creation of anything. thus rules are the way to create)
3. observer has own universe; the observed another universe; and the explanation is the way to define the observed so as can be conceived/ agreed by the rule in the universe of the observer.
4. thus, i think AL researchers will not come out from self-referentiality until some acknowledgement to identification of a (conscious?) designer (or have they? at least i know peter bentley acknowledged it). either in laying out some initial conditions, or and some rules; designing role exists in the very first instance in the creation of any universe.

another thing, while i waited about 3 hours standing outside NL embassy 6 - 9 am in 5 'C, i read swarm book and understand more about it (i always confused with the content before)

what i noted for now is p.184. the heading is: the interplay of self-organization and templates. first part they stated the essence of self-organization is attractivity, ie: inducement of snowball effect; the larger the cluster, the more attractive. but, the second part stated that "used by insects-or by other animals... combination of self-organization and a "template mechanism" in the process of clustering.
their definition of template: a kind of prepattern in the environment... to organise their activities. further along: "in the context of building, the shape to be built is predefined by the prepattern, and (the subject, insects or whatever) build along the prepattern"

thus i guess "template mechanism" is another kind of rule. like the preference in following the sortest path, is in a way a predefined rule we carry on while we experience space.

what im trying to say, is that, we should hope for co-evolution to emerge from our model of space and human-movement. but before that, all possible simplest rules have to be created so thus the universe of what we're looking at been made possible. i think we should acknowledge that Hillier created this simplest ever possible rule, but lack of "template". only template which could make possible preferentiality (happy or not happy). or all together Hillier's intelligibility should be use as our template.

i need sources to formal kind of intelligibility. rules created from Hillier's the concept intelligibility? its been in the back of my mind to research this for along time, but always seem to forgot. now i have to find this, from sources, since i see that framework above.

i dont feel like posting anything since i still can't modify the template. thus here's some stuff which soon appear
voronoi applet experiments; there will be quite lots of pictures.
agent's algorithms; partially debugged. this is the algorithms which will give us the occupational pattern (OP)

note: what's with crossed words? ha ha, just feel like using it.

wanna try audblog. something fishy, i cant change my template... oh well my template frozen now. help!