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Computer Modeling Should Become a Popular Hobby

qrg.northwestern.edu

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Re: Computer Modeling Should Become a Popular Hobby

#41

Post by gglitch »

sevensor wrote: post #40

I've had a lot of fun with agent-based and discrete event simulations. Hook it up to a visual and it's basically a game. Writing a basic simulation engine is also a lot of fun. Simulation is also the only application where I've felt comfortable with classical object-oriented modeling. I always find that object oriented programming forces me to deal with a lot of emergent complexity, but when you're doing simulation m…

Sounds awesome. Can you say more? What languages or environments, what kinds of things you're modeling, other writeups?

Re: Computer Modeling Should Become a Popular Hobby

#42

Post by zokier »

mojomark wrote: post #35
zokier wrote: post #15

It is a shame that the field is pretty undeveloped still after 20 years. Only recently there have been popping up few consumer CADs (fusion360/onshape), but those are still quite limited and of course do not satisfy free software user like me. Setting up decent physical simulations seems yet another whole endeavor even if you got your model done. There are few physics engines available, but using them seems to requir…

>>(fusion360/onshape), but those are still quite limited and of course do not satisfy free software user like me. Fusion360 is free (1). I used it for a while; though I didn't get into all of the features so I didn't really explore the physical simulation capabilities in depth, but I know it's supported to a degree (2). I'd imagine the FEA engine isn't as rigorous as paid software like say, Autodesk Inventor or Solid…

> Fusion360 is free (1)

I do enjoy the occasional beer, but it is no substitute for liberty; that path would only lead to alcoholism

Re: Computer Modeling Should Become a Popular Hobby

#43

Post by crankylinuxuser »

PeterisP wrote: post #28
phkahler wrote: post #26

Earlier quoted context omitted.

>> Einsteinian physics are incomplete, but it allows us to use satellites moving at roughly 10KM/s to pinpoint our location to within a few metres. Funny. I know how GPS works and that knowing the SAT locations is critical, but I never thought about how fast they are moving. They need to transmit their own position and time with great accuracy. In particular, don't they have to transmit their time and position at the…

GPS satellites aren't really transmitting their location at any particular time, they're transmitting the so-called ephemeris and almanac data that has information about their orbits so that you can calculate their position at the time of transmission.

And if you have a ADALM-PLUTO, you can download the brdc file (ephermis) and spoof all 12 satellites to a location of your choosing here: ftp://cddis.gsfc.nasa.gov/gnss/data/daily/2019/brdc/

https://github.com/Mictronics/pluto-gps-sim-win32

Re: Computer Modeling Should Become a Popular Hobby

#44

Post by nbeleski »

btown wrote: post #13
ssivark wrote: post #10

Agree broadly with everything in the article. However, I have one point to add: > Physical models that reproduce behavior are limited by the physics of the world, while computer models have much looser bounds. This is also one of the weak points of computer modeling. The outputs are strongly influenced by modeling assumptions, and without feedback from reality, one can easily be deluded towards wrong models. The comp…

"All models are wrong, but some are useful" - https://en.wikipedia.org/wiki/All_models_are_wrong

As someone who have computer modelling as a core of my research it makes me happy to see this quote mentioned here.

People on other science forums are generally fast to dismiss computer models as 'unrealistic' and 'non-representative', disregarding their utility.

For those interested in models I always recommend looking at Schelling's segregation model for starters, the premises and conclusions drawn from the experiment are quite interesting.

Re: Computer Modeling Should Become a Popular Hobby

#45

Post by sevensor »

gglitch wrote: post #41
sevensor wrote: post #40

I've had a lot of fun with agent-based and discrete event simulations. Hook it up to a visual and it's basically a game. Writing a basic simulation engine is also a lot of fun. Simulation is also the only application where I've felt comfortable with classical object-oriented modeling. I always find that object oriented programming forces me to deal with a lot of emergent complexity, but when you're doing simulation m…

Sounds awesome. Can you say more? What languages or environments, what kinds of things you're modeling, other writeups?

NetLogo is fun for toy agent-based simulation models. It includes visuals. For discrete event simulation, I recommend SimPy. If you like animations and you're willing to trade some personal info for free stuff, Simio has a free version that supports mixing discrete event and agent based simulation.

Edit: I realize I only answered about half of your question. I was in grad school when I did simulation modeling, this was about 5 years ago. I was working on modeling industrial processes. Simulation is great in that context because at a certain point queueing theory breaks down. I can't tell you how many talks I sat through that derived exciting conclusions from the assumption that all arrival processes are Markovian.

Re: Computer Modeling Should Become a Popular Hobby

#46

Post by jerf »

nbeleski wrote: post #44
btown wrote: post #13

Earlier quoted context omitted.

"All models are wrong, but some are useful" - https://en.wikipedia.org/wiki/All_models_are_wrong

As someone who have computer modelling as a core of my research it makes me happy to see this quote mentioned here. People on other science forums are generally fast to dismiss computer models as 'unrealistic' and 'non-representative', disregarding their utility. For those interested in models I always recommend looking at Schelling's segregation model for starters, the premises and conclusions drawn from the experim…

For myself, whenever I read about someone's new model and their predictions, I'm always looking to see what their model was verified against. If they've got a model, and it is verified to touch reality in some place we can check it, then I'm willing to at least listen to what the model says about where we can't touch, see, or test. It could be wrong, but it's at least the start of a conversation.

But if it's been verified against nothing, I don't have much interest in it.

Some examples of that include almost every model that claims to describe some element of human social interaction, which never seem to be checked against anything real that I can see, and I recall once reading an article and paper on modeling exoplanets and their likelihood of having life on them (or the likelihood of it being hospitable, not sure which) that flew so far beyond our science and data that the peer reviewers should be ashamed they ever approved it.

(Of course, if you want to publish your unvalidated model as an interesting piece of math, go nuts.)

Re: Computer Modeling Should Become a Popular Hobby

#48

Post by cr0sh »

zokier wrote: post #15

It is a shame that the field is pretty undeveloped still after 20 years. Only recently there have been popping up few consumer CADs (fusion360/onshape), but those are still quite limited and of course do not satisfy free software user like me. Setting up decent physical simulations seems yet another whole endeavor even if you got your model done. There are few physics engines available, but using them seems to requir…

I'm not sure that this would be useful to you, but have you seen or played with VPython?

https://vpython.org/

Re: Computer Modeling Should Become a Popular Hobby

#49

Post by jonsen »

Animats wrote: post #16
diydsp wrote: post #2

Recommend adding (1996) to title. That doesn't take away from it, it just shows how prescient the thought was.

Yes. It goes further back than that. That's what Alan Kay thought Smalltalk should be for. Read "Personal Dynamic Media". Going forward, there are the persistent shared modifiable virtual worlds, from There to Second Life to SineSpace and beyond. There are many good 3D CAD systems now, and the pro ones have some simulation capability. There's Minecraft and its imitators. We have the capability, and sizable numbers of…

It goes further back than that:

https://en.wikipedia.org/wiki/Simula

Re: Computer Modeling Should Become a Popular Hobby

#50

Post by rchaud »

diydsp wrote: post #2

Recommend adding (1996) to title. That doesn't take away from it, it just shows how prescient the thought was.

Yeah, when the page first loaded, I thought somebody actually took "motherfuckingwebsite.com" seriously and built a raw HTML page with no margins or padding beyond the browser defaults.
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