Models Definition and 400 Threads

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. K

    A Are there any theorems restricting possible QG candidates?

    String theory, being such a theoretically successful theory as it is but with no experiment to single it out as THE model among alternatives, Im left to wonder, which models can be excluded? Are there essential no-go theorems regarding the physics of a theory for QG? Im aware of the...
  2. jackkk_gatz

    Electric heat generation from parallel rods carrying current in an oil bath

    I know that ##\dot e_{gen} = \frac {R_{e}i^2} {\pi r^2 L}## the thing is I don't know the value of i. I didn't write it, but another thing that the problem asks is to determine the flow of electric current. The model I came up with using heat generation due to electrical current is $$ \frac...
  3. S

    I Models where all symmetries would be approximate?

    I found this interesting discussion here in Physics Forums (https://www.physicsforums.com/threads/are-all-symmetries-in-physics-just-approximations.1005038/) where the topic of all symmetries being approximate is discussed Is there any model (for instance, some type of spacetime metric or...
  4. A

    Neural networks as mathematical models of intelligence

    Why do almost all people not think that neural networks are the mathematical model of intelligence? I briefly explain what I understand: -A neuron is a mathematical object that takes numerical inputs from other nearby neurons, applies a nonlinear function (combining the input with numbers...
  5. binbagsss

    A Deriving Non-linear acoustic wave models, equilibrium state assumption

    The standard derivation in obtaining a single wave equation involves making use of the heat equation with a Taylor expansion of the equation of state, then differentiating this equation and the continuity equation with respect to time, and combining with the divergence of the NS equation...
  6. Math Amateur

    I Predicates and Models ... Goldrei

    I am reading Goldrei's book: "Propositional and Predicate Calculus: A Model of Argument", Chapter 4: Predicates and Models. I need help in understanding Goldrei's answer to Exercise 4.5 (a) ... Exercise 4.5 together with Goldrei's solution reads as follows: Can someone please explain exactly...
  7. F

    I Linear Models vs Nonlinear Models

    Hello, Models can be linear and nonlinear and I just learned that a "linear model" is not just a model where the dependent variable ##Y## is connected to independent variables ##X## raised to the 1st power... The model is called "linear" because the coefficients/parameters are not raised to...
  8. N

    I Do AEST (Absolute Euclidean Spacetime) models work?

    I was reading a paper by J.M.C Montanus which was published in <low quality journal reference removed> in which he claims under AEST the new gravitational dynamics and electrodynamics are reformulated in close correspondence with classical physics, and subsequently leads to the correct...
  9. T

    I Hubble Parameter as function of time in universe models

    This graph shows ##H## as a function of time related to the L-CDM model. Do we (@Jorrie) have similar graphs e.g. for ##\Lambda=0##; ##k=-1## critical, ##\Lambda=0##; ##k=0## open, ##\Lambda=0##; ##k=+1## closed? That would be great, thanks in advance.
  10. A

    I Some classical models of particles and quantum gauge theories

    My article has been published in Quantum Reports. Expanded abstract: There is currently no consensus on the interpretation of quantum theory, so this article may be of interest as it contains a review and new results on some relevant mathematical models emulating well-known quantum theories...
  11. atyy

    I Trouble for physical collapse models?

    https://www.quantamagazine.org/physics-experiments-spell-doom-for-quantum-collapse-theory-20221020/ Experiments Spell Doom for Decades-Old Explanation of Quantum Weirdness Physical-collapse theories have long offered a natural solution to the central mystery of the quantum world. But a series of...
  12. G

    A Exploring the Perception of Pain: Skeletal Models & Physics

    I am not cooking up a torture device or a weapon. In fact, I have been spending time with skeletal models. I just want to be able to create the ability to perceive pain. Even if I were to try to work this out myself and get some kind of answer that relates to physics, how would I know for sure...
  13. gleem

    Ethical and social risks of harm from Language Models

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  14. tysonman166

    MCNP6 Fatal Error : Models required

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  15. omega

    I Direct limit of multiverse models of ZFC

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  16. stephen8686

    Questions about Circuit Models of Transmission Lines

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  17. C

    I Queueing Models: Generator Matrix for M/M/2/2 & M/M/2/4

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  18. Barbequeman

    Consider three models of the Mass distribution in the Milky Way

    I attached a Jpeg with my attempted solution but I´m not sure if I´m on the right way... I hope for a correction in my calculations
  19. A

    I Why Are There So Few Quantum Time Machine Models?

    As of today, there are plenty of time machine mathematical models based on general relativity theory (warp drives, wormholes), but few ones based on quantum physics. However, back in 2010, Seth Lloyd wrote: "quantum mechanics supports a variety of counter-intuitive phenomena which might allow...
  20. M

    MHB How many stickers did Angel and Kareem have altogether?

    Angel and Kareem had some stickers. Angel had 5 times as many stickers as Kareem. After Angel gave 36 stickers to Kareem, both of them had an equal number of stickers. How many stickers did they both have altogether
  21. S

    MHB Can you solve this problem using bar models and ratios?

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  22. TheHeraclitus

    B Is an infinite universe compatible with cyclic models?

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  23. J

    I How well do cosmological models explain the observed µ vs. z data?

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  24. B

    Impedance/admittance (acoustic) models for outdoor ground and seafloor

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  25. T

    Applications Involving Drying -- Using Kinetic Models

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  26. K

    Uncertainties in climate models

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  27. JD_PM

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  28. M

    Question about Spectral Estimation using AR Models

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  29. N

    A question about the parameters/constants entering climate models

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  30. Arman777

    A What are the parameters that are the same in CMB data for multiple models?

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  31. S

    I Models and theories of laws of physics emerging from chaos?

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  32. S

    I Can Entropy Increase During a Probability Model Simulation?

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  33. S

    Models for weather that include data from amateur stations?

    I have the impression (I've not actually researched the matter) that some online weather services publish data from weather stations set up by amateurs. Do any organizations incorporate such data in their weather prediction models? I'd think that using such data would involve a sophisticated...
  34. S

    When are Lumped-element models used in the design process?

    Hi everybody, Academic papers in mechanical engineering use often lumped-element (or lumped-parameter) models such as a typical quarter car model. However, books about the (mechanical) engineering design methodologies (such as by authors Dieter, Shigley, or Pahl-Beitz) seem to not mention this...
  35. F

    3D Printing and "Watertight" Digital Models

    Hello, I understand that CAD models (stl files) suitable for 3D printing must be "watertight" and not leaky in the polygon mesh. By analogy, if we filled the model with water, the water would not leak...This concept of watertightness means that there are no unintentional holes between the...
  36. N

    Material Models Sources: Ludwik, Holomon, Swift, Wok, etc.

    Who can share the primary sources where material models are formulated: Ludwik, Holomon, Swift, Wok, Ludwikson, Hill and others?
  37. A. Neumaier

    A Advanced models for the Stern-Gerlach experiment

    A detailed discussion of measurement in the Stern-Gerlach experiment can be given in the POVM setting; see this post.
  38. S

    I IAU Rotational Models: Sol Solar System Planet Info

    I am developing my own project called orbital flight simulator myself. I was looking for some IAU rotational model about all planets (Sol solar system) through the Internet and my books but was unable find any information. Does anyone have good books or information (tables and algorithms like...
  39. W

    I Who was the first to find an initial singularity in GR models of the universe?

    I have a question about the history of cosmology, hope its okay to ask here. Who was the first person since Einstein's Gr to point out a singularity in cosmology? I know Freidman talked of an expanding universe and Lematire a primeval atom. But were there any explicit mentions of the density of...
  40. jim mcnamara

    Policy for pandemic issues and how models shape it

    https://www.sciencemag.org/news/2020/03/mathematics-life-and-death-how-disease-models-shape-national-shutdowns-and-other This shows how policy can be informed about differing effects of control policies in different environments. One of the bleak aspects of UK choices is shown as a graph...
  41. Prof Mark R Smith

    Insights 3 Possible Models For Why Uranus Spins on Its Side

    Continue reading...
  42. fRod57

    How do I predict rogue waves using simple probability models ?

    I need to predict an upcoming rogue wave or analyse old rogue wave events using simple probability models and real-time data for a physics high school project.
  43. A

    Relationship between Heat Capacity Cv for Different Models

    I think the C_V for van der waals gas will be larger than ideal gas since it‘s a more precise description. However, for the relationship I cannot come up with a specific equation.
  44. Adrian Tudini

    Computer models that predict the maximum power of a chemical reaction

    Given a balanced chemical equation, can we predict using computer models the maximum power of the chemical reaction? Thanks.
  45. T

    How to characterize mathematical models for comparison

    I am reviewing and comparing a wide range of mathematical models that are being applied to a specific realm of wildlife biology. For the comparison of these models, and to weigh advantages/disadvantages of different aspects with regard to application, I need to characterize each model. As I do...
  46. QuarkDecay

    A Friedmann-Robertson-Walker Models

    Can we say that a universe with a radiation density (only) exists only in near a Big Bang time, and not a Big Crunch? Since it gets much smaller as time passes. For example in here: http://www.nat.vu.nl/~wimu/Varying-Constants-Pictures/Time-Scale-Universe.jpg We have different cosmological...
  47. L

    I Best models to describe molecules

    Molecules don't really look like this with clearly defined objects and outlines. Remember that in the double slit experiments, we can't even model what happens between measurements, like how the electron behave between emitter and detector. So what is the best model to describe them? How...
  48. S

    I Confused by nonlocal models and relativity

    Hello everyone! Recently I saw this paper: https://arxiv.org/pdf/1304.4801.pdf ("Any nonlocal model assuming “local parts” conflicts with relativity " by Antoine Suarez). He mentions standard experimental configuration with beam-splitters and detectors. Then he distinguishes possible models...
  49. S

    I Are all Cellular Automata models of universes?

    Both Stephen Wolfram and nobel laureate Gerard 't Hooft think that the universe is a Cellular Automata. As far as I know, 't Hooft developped a series of frameworks to build different models of Cellular Automata and Wolfram also proposed a framework where network nodes could produce different...
  50. G

    Differing first-principle models for Maxwell-Boltzmann statistics?

    Let's consider a simple scenario in Maxwell-Boltzmann statistics: 6 identical but distinguishable particles, and 9 quanta of energy, 9 indivisible units, to be distributed among the particles.The first model is like that of the wheels on a combination lock, or should I say "permutation lock"...
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