What is Models: Definition and 400 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. Buzz Bloom

    I Qs re Cosmological Models Using Bayesian Probability Methods

    I am familiar with non-Bayesian methods for calculating best fit values of various parametric models, but I have not had any experience with cosmological models calculations. My understanding is that these models have five parameters: H0, Ωr, Ωm, Ωk, ΩΛ, and the last four satisfy the constraint...
  2. Auto-Didact

    Determinism: mathematical models

    Ever since Newton, determinism - i.e. the concept that the prior state of a system determines the next state of the system - has become an integral part of science, in particular of physics. This is particularly because Newton invented a mathematization of the concept of change: the calculus; in...
  3. QuarkDecay

    A Different FRW Cosmological Models

    ρο/a4 ρο/a3 k Λ Βig Bang Big Crunch Polynomial Expansion Exponential Expansion x 0 x 0 >0 x +1 x +1 x 0 <0 x -1 x -1 >0...
  4. A

    I De Broglie-Bohm theory and Bohm-like models - how is vacuum treated?

    Hi all, I've been looking at de Broglie-Bohm theory and more recent attempts at Bohm-like models that are relativistic and attempt to reproduce QFT. What I'm not clear on (non-expert) is how the vacuum is modeled in these cases? If we have a set of infinite quantum harmonic oscillators...
  5. Spinnor

    I A Quadrillion Standard Models from F-theory arxiv.org/pdf/1903.00009

    https://arxiv.org/pdf/1903.00009.pdf "We present an explicit construction of O(1015) globally consistent string compactifications that realize the exact chiral spectrum of the Standard Model of particle physics with gauge coupling unification in the context of F-theory. Utilizing the power of...
  6. R

    Extrapolating data points using models

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  7. A

    Simplified SUSY models with different mixing cases

    Hi Probably a bit technical, but here it is. I am trying to construct some simplfied SUSY models (that is, you only tune the masses of the core process, while all the rest are decoupled), and I would like to play with different mixing scenarios for the neutralino and charginos, so to get a...
  8. J

    Theoretical models of the Earth's Electric Field?

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  9. Rafid Mahbub

    A Exploring parameter space of inflation models

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  10. L

    Solving State-Variable Models Homework

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  11. tatkhj

    How do the Mobius and Klein models illuminate string theory?

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  12. FallenApple

    A Using incorrect models to infer correct ones.

    I see this happening a lot and have done this in my analysis as well. But it doesn't seem too intuitive to me as to why it works. So if we fit a linear regression, and the residual vs fitted plots are curved, we tweak the input variables to get a random residual vs fitted plot. But we have used...
  13. Nikhil N

    Model developed from performance curves are dynamic models?

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  14. Derek P

    A Discrete Models for Arguments and Continuous Variables in Quantum Mechanics

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  15. M

    I "Centaurus A Contradicts Dark Matter Models"

    According to the article in Astronomy Magazine June 2018, the satellite galaxies of Centaurus A are rotating in the same direction in a relatively thin plane, vs randomly distributed if there is a dark matter halo/sphere surrounding large galaxies. Any thoughts on this new finding? I've only...
  16. Leonardo Machado

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  17. F

    I Are these models true or even relevant?

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  18. M

    Pick a,b,c,d for y=ax^3+bx^2+cx+d that models path of plane.

    Homework Statement A plane starts its descent from height ##y =h## at ##x = -L## to land at ##(0,0)##. Choose ##a, b, c, d## so its landing path ##y =ax^3 + bx^2 + cx + d## is "smooth". With ##\frac{\mathrm {d}x}{\mathrm {d}t} = V =##constant, find ##\frac{\mathrm {d}y}{\mathrm {d}t}## and...
  19. SemM

    A What are some recommended books on non-standard quantum mechanical models?

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  20. B

    I Continuous Lensing Models: Discrete Data

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  21. SemM

    A Can Quantum Mechanics be Studied in Banach Spaces or Other Non-Hilbert Spaces?

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  22. L

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  23. M

    I Exploring Different Models of the Universe

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  24. O

    A Classical field models with infinite conserved quantities

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  25. D

    LaTeX Modeling 3 species using omnivory models. Latex code is included for the proof of continuity, etc

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  26. A

    How realistic are modern neuron models?

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  27. N

    Using Ideal and Constant Voltage Drop Models

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  28. f95toli

    Why do e.g. smoke detectors need specific battery models?

    I have once again come across a smoke detector which requires not only a specific type of battery (9V alkaline) but also a specific model (in this case Duracell MN1604) to be used. I had a similar problem with a CO detector about a year ago (which came with a list of about 10 models that should...
  29. ohwilleke

    I Looking for literature re imperfect quantum gravity models

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  30. Buzz Bloom

    I Models of accretion disc emissions contradicted by experiment

    Ref: http://www.spaceref.com/news/viewpr.html?pid=51416 I would be very interested to see comments from knowledgeable people about this. My impression is that this is one more example of a need to remain at least somewhat skeptical about theoretical models that have not yet been validated by...
  31. UsableThought

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  32. FritoTaco

    Models for Population Growth

    Homework Statement The Pacific halibut fishery has been modeled by the differential equation. \displaystyle\dfrac{dy}{dt}=ky\left(1-\dfrac{y}{M} \right) where y(t) is the biomass (the total mass of the members of the population) in kilograms at time t (measured in years), the carrying...
  33. H

    B ? about oscillating models of the Universe and Entropy

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  34. S

    Software to draw simple models

    Hi there, I am wondering if you have any suggestions how to draw these simple engineering models? Thank you in advance.
  35. W

    A Transcription from SQL to FOL (First Order Logic)

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  36. K

    I Interesting controversy about inflation models of the universe

    I'm opening this thread for discussion on the latest debate over inflationary cosmology as outlined over at scientific american the original article on inflation was Scientific American published an article by Ijjas, Steinhardt and Loeb https://www.cfa.harvard.edu/~loeb/sciam3.pdf then a...
  37. W

    I Plateau models of inflation after Planck

    Reading some of the critics and defenders of inflation in various papers, one thing I note they have in common is that both seem to agree the plateau models of inflation are favoured by Planck. According to one of the critics of inflation "The plateau-like potentials selected by Planck2013 are...
  38. BillTre

    Attempts to Unify Climate and Weather Prediction Models

    Open access news article from Science magazine news. I found this interesting, but it is really beyond my ability to provide a short explanation.
  39. Nathan Warford

    I Theoretical Models for Sizes of Fundamental Particles

    I am aware that according to the Standard Model of Particle Physics, fundamental particles such as electrons and quarks are treated as point-like particles. However, if fundamental particles are indeed 0-dimentional points with no spatial extent, it creates problems (i.e. fundamental particles...
  40. T

    A How to start my reading for 2D screening models

    Hi All, I needed some help or guidance starting my MSc reading, as there is tonnes of literature out there and it's difficult to understand what is necessary. I am beginning to look at applying screening models to a 2D system, such as the Thomas-Fermi continuum screening model, to a 2D system...
  41. anubodh

    A Resources for GRW, CSL collapse models

    I have extensively searched the internet but failed to find any exhaustive literature on the different collapse models of quantum mechanics.It would be really helpful if someone who knows can guide me on some exhaustive resources for the same.
  42. FallenApple

    A Should I Ignore Data Driven Models or Use Bayesian Methods for Model Selection?

    So it was mentioned that one should ignore data driven models because this could inflate the type 1 error as a result of overfitting. So the model should be decided even before looking at the data set. But at the same time, other sources say we should look at the scatterplot matrix to determine...
  43. gonadas91

    A Are two models with the same S matrix directly related by their parameters?

    Hello, I was wondering if two models show the same S matrix by a direct relation between their parameters, does that necessarily mean that both models are exactly equivalent? My idea is that this is true, but would like to know about a solid argument about it if possible, thank you!
  44. D

    Comparing Calculated Models to Real-Life Situations

    Hi :) im wondering if there is a video where a calculated model and the same situation in reality gets compared ? :) e.g. water drop, or something crashing with a certain speed :) thanks for any help :)
  45. J

    I Is proton decay considered in neutron star models (and LHC)?

    Although it is definitely not simple, there are many reasons to consider that baryon number can be violated, for example: - while baryogenesis there was created more matter than antimatter, - hypothetical Hawking radiation can finally turn any matter (mainly baryons) into massless radiation...
  46. F

    Parallel transformers - checking my models

    So on the left is a circuit which shows a voltage source and 2 coupled inductors in a parallel magnetic circuit shown on the right (transformer with a parallel core). Can someone tell me if I am modelling it correctly with the following equations? Rc1,Rc2,Rc3 are the reluctance of each branch of...
  47. durant35

    I Finite Universe Models: Exploring Plausible Models

    Hi guys, Based on what I know about the status of modern cosmology the question whether the universe is infinite or finite in extent is still open. Are there any plausible models in which the universe is finite and closed, despite the curvature being close to flat? Thanks in advance.
  48. S

    B How were differential equations for SIR Models calculated?

    Specifically:
  49. M

    Lattice Models for Fluids - Regular Solution Model

    1. Problem Statement: For the regular solution model, develop the equations for the compositions of the coexisting phases in a binary system and plot the phase boundary as a function of χ/RT.2. This question stems from Sandler's Introduction to Applied Statistical Thermodynamics. The Attempt...
  50. Martin1234

    ANSYS Material Models: Compression vs Tension

    Hello, I am doing a non-linear analysis in ANSYS. I have curve for the strain,stress curve for the material in tension, however, in the problem I'm working on I'm compressing the material. Does anyone know, if ANSYS just mirrors the material curve about origo as I have not given it data for...
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