# What is Model: Definition and 1000 Discussions

A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin modulus, a measure.
Representational models can be broadly divided into the concrete (e.g. physical form) and the abstract (e.g. behavioural patterns, especially as expressed in mathematical form). Of particular importance in the modern context, conceptual models are central to philosophy of science, as almost every scientific theory effectively embeds some kind of model of the physical or human sphere.
In commerce, a model might instead reference a specific version or configuration of a product offering, rather than functioning as a representation of something else.
In taxonomic settings (e.g. biology, architecture, art) a model is sometimes a particular instance of a set of related entities (species, built structures, artistic compositions) chosen as a convenient reference point around which to build discourse; such a model is almost always chosen to typify some central tendency of the group, exemplify the group's defining characteristic, or reify the group's historical lineage.
Kinds of models include:

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1. ### Experimenting whether the diameter of a pot affects boiling time for water

Hey guys, I'll try to be as direct as possible. So for school i'm doing an experiment at home trying to find out if the diameter of a pot affects the time it takes to boil water inside the pot as it says in the title. I had three different pots with three different diameters. I got half a liter...
2. ### How do I model this function? (Damped Harmonic Motion)

I first solved for the extension of the spring when its at equilibrium w/ the mass. I got Δx = 0.122m. I thought that if I added this with 0.1m, this would give me my amplitude. I then set 0.5m as my c value and plugged the rest of my values in from there. What am I doing wrong?
3. ### Comp Sci Greyjack, An Easier Model of Blackjack

See above.

I'm building a model as shown below (side, front, back). In order to measure its air resistance I will be mounting it on temporary ice blades (Green) and driving it down a long skating rink. The model has a pressure sensor incorporated into the motor / propeller assembly and a GPS unit to...
5. ### Can Mathematical Models Explain Scenes from The Day the Earth Stood Still?

This model diagram is possible when index0/index1=index1/index2=radius2/radius1 for the model's variables. 30 degree wave into a sphere. Reminded me of something out of that old science fiction movie, The Day the Earth Stood Still...
6. ### I New research puts age of the Universe at 26.7 billion years

The article https://phys.org/news/2023-07-age-universe-billion-years-previously.html#:~:text=42-,New%20research%20puts%20age%20of%20universe%20at%2026.7%20billion%20years,as%20old%20as%20previously%20believed&text=Our%20universe%20could%20be%20twice,%22impossible%20early%20galaxy%20problem.%22...
7. ### Wheelie of a car coming out of a ditch: what is the correct model?

I ask for help in interpreting this question. Thank you !
8. ### Create a Mask-RCNN Model in Python for Smart Parking Systems

Homework Statement: I am trying to write a Python code to do a project about smart parking system. I want to create a Mask RCNN model to detect the vehicles in the parking slots. My code is attached below, I got an error in the last line (creating Mask_RCNN model) and do not know how to solve...
9. ### A Discussing the Sachdev–Ye–Kitaev Model

Currently it's a very hot topic, so it would be nice to have a thread on this. Those who never heard of it may start from https://en.wikipedia.org/wiki/Sachdev–Ye–Kitaev_model A good review is https://arxiv.org/abs/1711.08482
10. ### I How can I model squeezed states in 3D optical modelling software?

I would like to model squeezed light and its evolution (such as when passing through lenses after being generated) using optics software such as OptiFDTD or ZEMAX. However, I don’t see any way to make such states…my plan was to simulate an Optical Parametric Amplifier to generate these states...
11. ### Comp Sci Acoustic Model and Language Model

Question: My Answer: Is it correct? Thank you
12. ### Python BigGANModel -- Trying to train a model to generate images

I am trying to train a model to generate images, I have a dataset of over 17K of men posing. I have been training my model for a few hours now and Sadly all I am getting is this: Also my d_loss=-9.79e+3 how is it Negative ? here is my code: # -*- coding: utf-8 -*- """BigGANModel.ipynb...
13. ### Problem on SSH Model Tight Binding Approach

I'd like to proceed in a linear fashion, taking each part on one by one. For the first part, we can write the Hamiltonian as ##H = \sum_{n}^{N} w(c_{An}^{\dagger}c_{Bn}+c_{Bn}^{\dagger}c_{An})+v(c_{Bn}^{\dagger}c_{A(n+1)}+c_{A(n+1)}^{\dagger}c_{Bn})##. We can convert the creation and...
14. ### I Linear Model with independent categorical variable

Hello, I have been pondering on the following: we have data for blood pressure BP (response variable) and data about age and gender (categorical variable with two levels). We can build two linear regression models: $$BP=b_0+b_1 age+b_2 gender$$ $$BP=b_0+b_1 age$$ The first model does not take...
15. ### Python FineTune the Pixel2Style2Pixel model with my custom data set

I want to fine-tune the Pixel2Style2Pixel model with my custom data set, but I keep getting an error when I'm trying to load in the pre-train weights. Here is my code : # Load the pre-trained model os.chdir("/content/pixel2style2pixel") from models.psp import pSp config = { "lr": 0.0001...
16. ### Thermal lattice Boltzmann model ignoring source term -- python code help please

LBM model for phase change- relevant equations found here. Also here. #Thermal LBM #solves 1D 1 phase phase-change #D2Q5 Lattice nx=100 # the number of nodes in x direction lattice direction ny=5 # the number of nodes in y...
17. ### Mathematica Trying to model red and grey squirrels

ClearAll["Global`*"] (*R = reds, G = greys*) (*S = susceptible, I = infected, R = recovered*) tseries = {t, 0, 3}; vars = {HG[t], HR[t], SG[t], IG[t], RG[t], SR[t], IR[t], aG[t], qG[t]}; b = 0.4; (*natural mortality rate, both species*) \[Beta] = 0.7; (*rate of virus transmission*) aR =...
18. ### A Moire potential depth from continuum model

Dear All, I am trying to calculate the moire potential depth of transition metal dichalcogenide system. I have attached supporting material obtained from one of the thesis. Here they have describe the continuum model hamiltonian for TMDs homobilayer. My question is how to obtain the moire...
19. ### B What exactly is spin? Does the standard model work without spin?

I did some research online and found that "When certain elementary particles move through a magnetic field, they are deflected in a manner that suggests they have the properties of little magnets." To explain this phenomenon, physicists invented the concept of spin. So far so good. What I...
20. ### I Can a scalar field model account for the cosmic redshift?

A minimally coupled scalar field can model a cosmological fluid model where And where the equation of state can be the standard ## \omega = \frac {p} {\rho}## I can see how this does a fine job modeling matter, because as the scale factor increases, the density will go as ##\frac {1} {a^3}##...
21. ### B Model rocket physics: Why doesn't the motor go through the nose cone?

For those who have built those small model rockets, please help me understand a very very simple physics problem that i for some reason do not fully get. Why is it that the motor tube does not have a retention ring on it, to prevent the motor from flying out the nose cone? i know it cant be...
22. ### Model for Gravity -- What mechanism distorts space in the real case?

Homework Statement:: Model for Gravity Relevant Equations:: Rg -Rg = G/(8pi*c^4)T The rubber table model for gravity can't quite translate to reality. One sees that a ball placed on the table distorts it, but this is due to it being in a uniform gravity field. Just what mechanism distorts...
23. ### Finding the terminal velocity of a model rocket from a list of velocities

Ok, i have some rocket data from a 20,000 foot launch. I have the times, altitudes, and velocity at said time. Is it possible to find the terminal velocity from this long list of numbers? I tried graphing the velocities to see where the curve flattens out, since usually that is where terminal...
24. ### What is the oscillator model in a generalized Snyder scheme？

What is the oscillator model in a generalized Snyder scheme？How to derive the formula？
25. ### A Fourier optics model of a 4f system

In my system I am trying to represent two lenses. L1 with focal length f1=910mm and the other lens, L2 with focal length f2=40mm. These lenses are space such that there is a distance of f1+f2 between the lenses. I have a unit amplitude plane wave incident on L1. My goal is to find the...
26. ### A How Many Hidden Variables Would It Take to Model Photon Polarization?

Suppose the EPR* concept were true as it would be applied to entangled photon polarization. (Please note: I am not saying it is.) They thought QM was incomplete, because there must exist "elements of reality" (hidden variables) that supplied the highly correlated results on entangled particle...
27. ### A Non-significant variables in a logistic regression model

If some variables of a logistic regression models are non significant, should they be considered for a risk index calculation? Should the logistic model include only relevant variables? Thanks for the attention.

29. ### Better model for a hydraulic motor

Hi all, We are doing some work with Eaton 760 series fixed displacement hydraulic motors and are looking for a better mathematical model for the torque output. Does anyone know a good place to look? Something that includes differential pressure and temperature would be ideal. Thanks Ed
30. ### I Measuring Model Rocket Velocity: Is it Possible?

Question, if i record a video of a model rocket launching, and then falling, is it possible to get the actual (or extremely close) velocity every 1 second? thanks

33. ### Total force from air spring model (double acting piston)

Hi everyone, I'm an electrical engineer working on making a linear model for a power take-off system. I've gotten inertial, friction, and hydraulic/electric components done, but what is really confusing me is the gas system; I haven't taken ANY thermodynamics. To simplify it, it is modeled as a...
34. ### A Negative slope in Williamson-Hall model

Good afternoon, I am analyzing a diffraction diagram (XRD) corresponding to a powder diffraction experiment , and I have obtained a negative slope value when plotting ##\left(\beta_{exp}-\beta_{inst}\right)\cos\theta## vs ##\sin\theta##. This implies that the strain coefficient is negative for...
35. ### Isospin and Partons model in a pentaquark

TL;DR Summary: Given a pentaquark: (a) Determine the isospin multiplet it belongs to. (b) Calculate a kind of a Gottfried Sum Rule for this pentaquark-neutrino or -antineutrino scattering. Hello everybody, I'm having a bit of a trouble with the exercise below as it deals with a pentaquark and...
36. ### Is there a library for the Gibson-Ashby model in Abaqus?

Hello together, I need help for my bachelor thesis. We want to simulate the mechanical properties of polyurethane foam using the Gibson-Ashby model in Abaqus. So I would like to know if there is a library or something similar for Abaqus. I'm fairly new to Abaqus and the Gibson-Ashboy model, so...
37. ### Impact force of model rocket with parachute

I just launched a 2.2kg model rocket that stands about 5 feet tall and has a airframe that is 4 inches in diameter. I am trying to find how much the impact force is when the rocket hits the ground at 16MPH. Whats the best approach? Momentum? KE? or something else:) thanks
38. ### Question about the Microscopic Model of Current

Why do they say uniform conductor? Many thanks!
39. ### A Could a CPL parametrization be included into Brans-Dicke model?

I have studied up to now about forecasts to constrain cosmological parameters in the context of CPL( Chevallier-Polarski-Linder ) parametrization with w_0, ,w_a parameters in equation of state for cosmic fluid. For this, I have used Matter power spectra ("fake data") generated by CAMB and CLASS...
40. ### Geert Hofstede's 6-D model of national culture

That quote be true, yet we are so different. The quote is from a Freakonomics Podcast. That led me to the web site https://geerthofstede.com/culture-geert-hofstede-gert-jan-hofstede/6d-model-of-national-culture/ I think that these cultural differences and the insights they provide are very...
41. ### I Is Connes' Model of the Higgs Field a Wormhole?

As this week the great topic is the Einstein-Rosen bridge and duals of it, I wonder what happened with the interpretation of Connes NCG model as two sheets of spacetime whose separation is measured by the higgs field. How is it different of a ER bridge?
42. ### Calculations using the Standard Solar Model & Solar Equations of State

Assuming the Sun’s core has a mass of 0.35 Msolar_mass and taking values for other quantities from a internet background search or from the following figures (i.e.: Radius "solar core" = 0.25 Rsolar_radius ): ------------------------------------------------------------------------...
43. ### What should I do with my spacetime model?

I created a model of spacetime based on an extension I added to the principle of relativity. I then derived the coordinate transformations which preserve the speed of light in all frames, which are different from the Lorentz transformation. I worked out the formulae for energy and momentum, and...
44. ### High Energy Literature for introduction to O(N) vector model

TL;DR Summary: Looking for literature on O(N) vector model Hello, We have been going over the O(N) vector model in my QFT class but the notes are not very detailed and we are not using a textbook. Does anyone know of a good QFT book which goes over this material? I have a copy of Shrednicki...
45. ### Einstein solid state model exercise

I tried to solve it considering the canonical ensemble (since the system is at the equilibrium with temperature T) and started finding the partition function:The problem is I am not sure if I have done it correctly and need help because I don't really know where to check.
46. ### Nuclear shell model of double magic nucleus 132Sn

The independent particle energies for protons and neutrons around the exotic doubly magic core 132Sn are shown in the figure below, where π refers to protons and ν to neutrons. Using the nuclear shell model and using this figure as a guide, answer to the following questions: a)Estimate Jπ...
47. ### B Is the Standard Model overfitted?

Is the Standard Model overfitted? I hear that the standard model is the most accurate model that we have so far showing accuracy of 13 digits or so. However I am wondering if this accuracy comes from adding so many constants until it fits. First of all the standard model takes in 25 constants...
48. ### Partition function of modified Ising model

$$H = - J ( \sum_{i = odd}) \sigma_i \sigma_{i+1} - \mu H ( \sum_{i} \sigma_i )$$ So basically, my idea was to separate the particles in this way:: ##N_{\uparrow}## is the number of up spin particles ##N_{\downarrow}## "" down spin particles ##N_1## is the number of pairs of particles close...
49. ### A What is a "transient" value in the Ising model?

What is a "transient" value, result, or state in the Ising model? How do we treat these values during the simulation? Do we discard these values? If so, why?
50. ### This is a 3D model I made of a nuclear power plant control room

I spent the past several weeks making this 3D model of a nuclear power plant control room.