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Questions tagged [modeling]

The tag has no usage guidance.

0
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2answers
50 views

Are there any studies on finding cellular automata rules for modeling specific systems?

While playing around I managed to design a Cellular Automaton (CA) that behaves like a fluid. Very basic behavior, like diffusion, obstacle avoidance, pressure etc. And that got me wondering about it. ...
4
votes
1answer
152 views

Expanding Winding Number algorithm to arcs

I have a problem that I have been attempting to solve for a few days now. I was wondering if I would be able to get some assistance from the community. In order to detect if a point is in a polygon, ...
4
votes
1answer
55 views

How to preserve or recover states meanings in canonical state-space realizations

Let assume that one would like to translate an input-output model, into a state-space one. It is well-known that the process of realization addresses this aspect. Let assume to have the following ...
0
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1answer
53 views

Simulation of a complicated projectile motion

I'm trying to model a projectile motion, considering every detail such as projectile aerodynamics, effects of wind, air temperature etc. What is a good software to model it in with good graphics? I ...
0
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1answer
58 views

On which software can I simulate landmass collisions?

I need to be able to set the properties of the materials (density, size etc) and see what happens according to laws in Physics when landmasses collide each others, with or without bodies of water, ...
7
votes
4answers
187 views

In Matlab, how can I be consistent with units?

I am modeling some aerodynamics equations and am using meters / centimeters, kilograms, and seconds. I've heard that, "matlab doesn't know units". So, how can I make sure that it does? Just ...
1
vote
0answers
26 views

modelling surface coverage of spheres with spheres of varying size distribution

Suppose you have spheres (e.g. cells). You add particles to the suspended cells which are smaller but do have a size distribution rather than a single diameter. The particles stick to the cells. I ...
1
vote
0answers
231 views

Inputting a time dependent function into ODE45 [closed]

I am currently trying to model random waves on a buoy system. I am running into the issue of implementing a random wave function. ...
2
votes
1answer
134 views

Chattering effect using ode23s — SDOF with variable spring and periodic input force

I am attempting to model the following SDOF system with a variable spring and having a sinusoidal input, $$m\ddot{x}+(k_0+k_1)x = m(2\pi f)^2\sin(2\pi ft)$$ where $m$ is the mass, $k_0$ the original ...
1
vote
1answer
382 views

Curve fitting for oscillating data

This is my first question. I have the following data that I'd like to approximate as a parametric function: \begin{align} y = a + (bx_1 + cx_2 + dx_3 + ex_1x_2 + fx_1x_3 + gx_2x_3 + hx_1x_2x_3 + i)*(...
4
votes
1answer
108 views

Is a divide by zero error an indication of a bad conceptual model?

When we create numerical models of a real-world system, we usually go through a few phases (from Abramowitz 2010): a perceptual model, where we consider the relevant components of the system a ...
0
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1answer
39 views

Express the $\gamma_{2}^{\epsilon}$ SemiDefinite program in a form that is acceptable by SDPT3

I'm trying to express the following semidefinite program: for given $A \in R^{m \times n}$ and a scalar $\epsilon \in (0,1)$, \begin{align} &\gamma_{2}^{\epsilon}(A):= \min\,t\\ &\text{...
1
vote
0answers
27 views

How to find active region in treepartition Matlab object

I am trying to identify a non-linear plant using the identification toolbox of Matlab. In particular I would like to identify a non-linear arx model, where the nonlinearities are expressed by means ...
1
vote
0answers
94 views

How to get mathematical model from a data set with MATLAB

I have some values imported from excel about the annual sell of a product, with 3 var: month, price, sold items I have seen how to plot a chart using curve fitting tool but I need to define a ...
2
votes
0answers
31 views

Limitations of particle in cell method for high density plasma

Are there any limitations of particle in cell (PIC) method for high density plasma? To be more specific, is modeling of a narrow channel of high density plasma possible or are there any limitations ...
0
votes
1answer
479 views

Solving coupled differential equations and Algebraic equation in MATLAB

I want to solve a system of 7 coupled differential equations and 1 algebraic equation in MATLAB with the method of lines. I could do it for each independent equation with some assumptions, but I can'...
3
votes
1answer
738 views

Computer Build for Scientific Computing

I am currently a .NET software developer(SQL Server, ASP.NET, C#, MVC & Web Forms). In my spare time I'm researching different areas of environmental science. E.g.(Hydrology, Ecology, Atmospheric ...
1
vote
0answers
105 views

Conditions for always positive gradient of heat field in evolutionary thermo-elastic system

I am investigating stability and convergence of series of approximations for coupled thermoelasticity problem yielded by one-step recurrent time-integration scheme. I've managed to show that the one-...
12
votes
3answers
11k views

Alternatives to Comsol Multiphysics

This might be a question better suited for the Software Recommendations side of S.E., however I do believe that people who frequent this part of S.E. are more likely to be able to answer this question....
0
votes
1answer
1k views

scipy.integrate.odeint: how can odeint access a parameter set that is evolving independently of it?

I might have some non-linear ODEs that are being solved by scipy.integrate.odeint. However, a parameter at each time step might have to be updated by using a non-DE ...
9
votes
2answers
629 views

How to model a fishing rod (or a rope)?

I wish to model a fishing rod (or a rope) by joining short segments. (The segments may have equal (short) length but each segment should be assigned its own individual mass.) One segment will ...
2
votes
1answer
3k views

PDEs in their weak form in Comsol

If a physical model is not listed in the wizard, we can use Comsol's weak form to enter PDE's (governing equations of a system) in their weak form. How can it be done ? for example: 2 equations of ...