Simulations

[Aur]

Hi! I just found this site, while researching different ideas for simulations.

Basically I have to come up with a complex problem that I can simulate on a computer, using a language of my choice. I have a few months to do this, so I'm trying to find a project that I find interesting.

At the moment my favourite idea is a crowd simulator. But I'd be welcome to hear anyother ideas on simulations. Thanks for any help.

[Pyrotex]

Originally Posted by Aur

Hi! ...At the moment my favourite idea is a crowd simulator. But I'd be welcome to hear anyother ideas on simulations. Thanks for any help.

Hi! And welcome to Hypography!

Funny you should ask that. I've done quite a bit of simulation over the years as part of my job(s), and one day hoped to find a language I could use to do my own "sims" at home. Obviously, there are many such languages now. But I don't have the time!

The one sim I always wanted to do was to simulate traffic on a multi-lane, limited access highway. Like an interstate. I got the idea while driving on the LBJ Freeway that circles Dallas. I would build a sim of a "circular" interstate loop, with L lanes (where I could set L in the program), and X exit ramps and N entrance ramps.

The "cars" would be the heart of the sim, because it is there I would be able to simulate not just the vehicles, but their DRIVERS. So, some car parameters would be:
Average driving speed over the posted speed limit, as an average (+ or -);
Average acceleration rate, when accelerating
Average braking rate, when braking
Probability of using turn signals
Average drift rate when changing lanes
Visual knowledge, measured in meters ahead of their own vehicle
Mirror knowledge, measured in meters behind own vehicle
Left knowledge, size of blind spot on the left
Right knowledge, size of blind spot on the right
Closing rate fright (how fast must they be closing on a bumper before they hit brakes)
Closing distance fright (how close must they be to a bumper before they hit brakes)
Probability of urge to change lanes
Drunkenness factor, 0-100, where 100 means random steerage and speed
Probability of responding to turn signal within Visual knowledge
Probability of responding to brake lights within Visual knowledge
Probability of being uncomfortable next to car in next lane
Probability of responding to any urge or discomfort by changing lanes
Probability of urge to go faster
Probability of urge to slow down
Probability of checking blind spots before changing lanes

Separate from the cars, other parameters I would control would be:
Average time between new car entry, at entrance ramp N-sub-a
Average time between car exits, at exit rampt X-sub-a
Lane blockage at position P, lane L-sub-a.
Speed rate X turn rate yielding non-zero probability of loss of control (NZPLOC)
Speed rate X brake rate yielding NZPLOC

You get the idea.
Then I would set up the sim for, maybe 4 lanes, 10 miles around the loop, speed limit of 60 MPH, turn on the entrance ramps until I had a density of about 1 car per 20 meters per lane and see how accidents happen. And how this affects traffic flow.

I also want to see if I could simulate "reverse compression waves" in an otherwise normal flow of traffic. This is where at a specific traffic densities, at one position in the loop, the cars get closer together, slow down, then speed up and get further apart, forming a temporary "clump" -- this clump travels BACKWARDS around the loop, typically at speeds about 1/4 of the forward average traffic flow. These things are REAL, I've been in quite a few of them!

[Southtown]

I've seen that before in dense traffic. I consciously try to negate it by being slower to speed up or slow down than the guy in front of me. The stop and go just aggravates me to no end.

[Jay-qu]

Pyro, I think about how I would simulate traffic everytime I am stuck in it! It gives me something to think about :P

I have simulated a few things over the years. Electrons in magnetic fields, atoms in magnetic traps, billard tables, gravitational systems (3-body problem), stellar burning, evaporative cooling and probably some more

[Pyrotex]

Yeah, simming a physical situation is lots of fun, even if only in my mind!

[CraigD]

Welcome to hypography, Aur!

If you check around hypography, you’ll find code and example of several simulations, more than a few of them by me. One of my favorite is the program in Newtonian Bowling, an example of a less common “event based”, as opposed to “clock tick based”, sim. It’s also unusual because, like most of my hobby sims, it’s written in an unusual style of the MUMPS language. I’ve also a couple of general-purpose gravitational system simulators, XGRAVSIM2 and XGRAVSIM4.

My personal pet agent-based simulation – which I’ve been sadly lax in actually implementing – is a simulation of contagious zombies and fighting/fleeing frightened masses. I’m partial to the barely intelligent, clumsy, slow-moving zombies of the Romero movies, but many variants can be taken from an extensive genre of books and movies.

I think this affords a great advantage vs. an ordinary crowd agent-based sim, as it has clear metrics - number of zombies & number of “warmies” - and clear game victory conditions – 0 zombies or 0 warmies.

A clear disadvantage of a zombie sim vs. most sims is that it’s completely fantastic, so has next to no practical application. As a good, versatile agent-based sim should be able to model many different variations of its main theme, it should still be a good exercise, and applicable to simulating real things.

I’m looking forward to seeing your sim code

[Pyrotex]

Hmmm, Craig,
I would very interested in seeing a zombie sim. Wow.

[Jay-qu]

Originally Posted by Pyrotex

Hmmm, Craig,
I would very interested in seeing a zombie sim. Wow.

Yeah I smell a new thread coming on. I can see a visualisation already, little red dots slowly moving around the screen seeking out the frantic blue dots..

There should also be an option to give the 'warmies' weapons

[arkain101]

At the moment my favourite idea is a crowd simulator. But I'd be welcome to hear anyother ideas on simulations. Thanks for any help.

Recently, I was searching old topics on this site. One of the ways I filtered the topics was by clicking the "views" link which organized all of the links from most views, decending top down.

Here are some examples of a few Physical Sciences (in most views order)

Space

Space - Science Forums

#1 Aliens poll views 16,716







Physics and Mathematics

Physics and Mathematics - Science Forums

#1 TIME EXPLAINED (v2.1) views 147,624









Alternative Theories

Alternative theories - Science Forums

How soon will a moneyless society change the way we percieve each other? views 8,343











Biology

http://hypography.com/forums/biology...esc&sort=views

Parasites views 21,478









Maybe you could do something of this nature to simulate a crowds common interests. Questions to ask could be:

-What is the most common specific interest or theme amongst a crowd

-What are some of the overall interests of a crowd

-Why does a crowd favor one kind of topic over another

-Is there any patterns that emerge

(taking into consideration and categorizing the age of the topics)







I thought about looking into it more myself.. Have fun.

[Boerseun]

Hi there, Aur, and welcome to Hypo!

Hypo is actually is forum with no real members; Tormod devised the whole thing as a Social Website Simulator. He lives in his mother's basement, and all the postings you see here are merely figments of his imagination and manifestations of his multiple personalities.

But as a forum simulator, I think he's done a cracking job... Couldn't tell it from the real thing! He even gets to ban himself several times a night!