What is Modeling: Definition and 607 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. Leo Liu

    (Control) Derivative filter and discrete model

    Hi I am back :). I have been doing some Simulink modeling for a project. I modeled it with a discrete system due to the controller rate. I have noticed that for all the discrete system I have tried, adding a derivative filter not only improves the performance (smaller settling time), but it is...
  2. A

    Modeling an earthing switch for a High Voltage Impulse Generator

    Hi All, I am trying to model this mechanism for a project. It is a switch that uses a solenoid to break the contact by lifting the aluminium arm. I understand that there is most likely software out there that can do this but i would like to understand how to model this from first principals. I...
  3. rodv92

    ABC reference frame synchronous generator modelling in Ltspice

    I started to study synchronous generator modelling some time ago... Quite a rabbit hole to say the least. So, there are basically two types of models : abc reference frame models aka phase variable models and dq0 reference models. dq0 are primarily used for steady state modelling of generators...
  4. lavendersmell

    I [Questions] Modeling a Baseball Pitch Trajectory in 3D Space

    I am currently taking some time off of college (I am a sophomore), and I'm trying to continue coding and experimenting with Calculus-y math as I'll be going into Calculus II and then III when I go back. I am currently trying to develop a 3D baseball pitch visualizer for my own purposes. I am not...
  5. A

    A Constructing PDFs for Max Likelihood Density Estimation Problem

    I have the following constrained optimization problem corresponding to the maximum likelihood density estimation: $$ \begin{aligned} &\text{maximize} && L(f) \\ &\text{subject to} && f \in H \\ &&& \int_a^b f(x) \mathop{}\!\mathrm{d} x = 1 \\ &&& f(x) \geq 0...
  6. chengmo

    MCNP macro definition modeling

    I use macro definition to model the results can be viewed in vised but vised does not display all the big guy know? Is there something wrong with my modeling?
  7. chengmo

    MCNP macro definition modeling

    C 1 1 -19.35 -7 1 -2 2 1 -19.35 -8 3 -4 3 1 -19.35 -5:-6 4 0 5 6 #1 #2 C 1 RCC 0 -10 0 0 -10 10 2 2 RCC 0 -10 0 0 -10 10 5 3 RCC 0 10 0 0 10 10 2 4 RCC 0 10 0 0 10 10 5 5 RPP 2 5 -10 10 0 10 6 RPP -3 0 -15 15 0 10 7 RPP 0 5 -15 -10 0 10 8 RPP 0 5 10 15 0 10 C M1 074184 1
  8. Astronuc

    Modeling and Simulation in Nuclear Energy

    Modeling and simulation, or computational physics/chemistry, is a large and important part of engineering. In nuclear energy, there are applications of finite element methods (and occasionally finite different or finite volume depending on the problem) applied to nuclear plants, nuclear...
  9. James1238765

    I Modeling the Earth and Sun (2 body orbits) using general relativity?

    Modeling the time evolution of the sun and earth orbiting each other using ##F = \frac{GMm}{r^2}## is straightforward. However, it appears that modeling the time evolution of the same 2 body system using general relativity seems to be a hard/intractable problem? There was in depth discussion by...
  10. A

    I Modeling the concentration of gas constituents in a Force Field

    Say there is a gas made up of two gas molecules: Molecule A and Molecule B. Molecule A has a mass: ma and mole fraction: na. Molecule B has a mass: mb and mole fraction: nb. The gas is at thermal equilibrium and has a constant temperature throughout itself (T) everywhere. It is placed in a...
  11. F

    Modeling a kongming lantern (sky lantern)

    The problem gives these data external (cold) air temperature: ##T_c = 20^\circ{\rm C}## internal (hot) air temperature: ##T_h = 80^\circ{\rm C}## lantern volume ##V=0.2 {\rm m^3}## lantern surface ##A=2.0 {\rm m^2}## lantern mass ##m_{\rm L}=30 {\rm g}## external convective heat transfer...
  12. F

    I Why are free parameters bad for a theory?

    It is often said that one of the drawbacks of the standard model is that it has many free parameters. My question is two-fold: What exactly is a free parameter? My understanding is that the free parameters of a model/theory are the ones that cannot be predicted by the theory and need to be...
  13. vipers120

    I Modeling a (rotating) mass impact on a preloaded (rotational) spring

    I am trying to model numerically the following system: A rigid body mass is rotating freely around an axis (no rotational stiffness/damping) within a range, let's assume plus-minus 3 degrees for now. Case A. The external forces on the mass are low and keep changing which results in the situation...
  14. B

    Mathematically modeling a real system in C#

    How can I mathematically model a real system and predict values from that system? I have a real device that produces data that I can graph. The data looks like a sinewave. I want to use an sinewave fit equation to predict some of the measurements because of how long it takes to run a...
  15. E

    Quick doubt about catalysis modeling

    how does the partial pressure of oxygen (O2) that is raised to the (1/2) power "magically" combines to give PSO3? , i know that at constant Temperature you can pretty much express pressures between reactants and products using conversion but still you won't be able to factorize because they are...
  16. Lord Doppler

    Engineering Solving Car Suspension Modeling: Understanding Input Forces and Movement Types

    Hello, I'm trying to solve this problem but I'm confused with some things, is correct that in the system there are two input forces, the torque and u(t)? I assumed that the system has two free levels, which are the z displacement and theta (rotational movement), so the system has a linear...
  17. willDavidson

    Understanding PV Cell Modeling: Single vs Double Diode

    I am looking at modeling a PV cell and I'm trying to understand the real difference between the single diode and double diode mode. I now realize that I don't fully understand the purpose of the diode in the model in the first place. I've just learned that it was there and went with it. I...
  18. S

    Engineering Cantilever Modeling System - Help requested please

    Please see question attached. I am really stuck on this.
  19. P

    Engineering Small signal AC modeling for a boost converter with resistive losses

    I've attached my attempts at the solution and the actual question below. I believe the only issue I am having is I don't know how to get rid of "I" in both my final inductor and capacitor equations as the HW states I shouldn't have anything in term of I. I believe I need to put "I" in terms of...
  20. Devs

    Engineering Mathematics modeling for a Mass-Spring-Damper system

    Summary:: How can I get mathematics modeling for these tree systems? First of all, my mother tongue is not English, so my expression could be ambiguous. I want to get mathematics modeling for these three system above, like this form. First one is b -> (b1+b2), right? but I'm not sure...
  21. BWV

    The Imprecision of Modeling Real World Events

    find the whole idea of modelling real world events involving human beings an interesting intersection of math, science and bull####. The idea of assigning a probabilty to a complex event like an election seems like scientism at its worst. If someone who has studies past elections says ‘my...
  22. T

    Rotational Dynamics - Modeling brake caliper deceleration of a chassis

    I am a junior engineer tasked with modeling the dynamics of a small research UAV after landing. The UAV has 3 tires, 1 on the nose landing gear and 2 on the rear landing gear. The rear tires are equipped with disc brake calipers. My coworker has explained that the simplified model (MODEL 1...
  23. T

    Simplified modeling of teledeltos paper

    I'm writing a physics simulation to mimic the old equipotential mapping experiment like this one. I can't find much information on how the voltage across this semi-conducting sheet relates to the E-field. Before I start heading down the path sheet resistance and the resistivity of thin-film...
  24. J

    Modeling Uniform Field Gap Electrodes, Rogowski or others

    Hi, I am trying to design uniform field gap electrodes using the Rogowski profile. I've read some papers on it, but I'm completely new to this and I am just having a hard time translating what's in the paper to my Matlab code to produce the same results. I'm not sure if this is the right place...
  25. G

    Modeling Stress in Simple Objects: Easy Software Options?

    I am trying to model stress in simple objects such as a disk, a cube, a rectangular prism or a solid ball under their own weight or additional point mass weight on top to demonstrate such material response to students. I understand the usual process is to set up Mesh, boundary condition, and...
  26. SalahAhmed03

    Modeling an Induction motor in ANSYS Maxwell 2D

    Hii Friends. I was trying to model an Induction motor in ANSYS Maxwell 2D. The final output of Transient torque (negative torque) looks like shown below. The input passed is a sine wave current with 120 deg phase shift. Any Suggestion will be highly appreciated
  27. M

    Modeling a spark gap--How to solve a DE with a step function

    Honestly not sure how to go about this. Again this is one equation of 4 that I have. I considered using Laplace transforms but taking the Laplace transform of a step function whose argument is one of the variables being solved for doesn't seem possible. Also, if there is an alternative way to...
  28. SilverSoldier

    Mathematically Modeling a Rolling Body with Slipping

    Basically, I want to know if my assumptions and workings are correct. This is how I see this situation. First, I'm viewing this body as a series of disconnected points, like I have in this animation I made, modeling purely rolling motion. Modeling the body like that worked in that case, and...
  29. V

    Modeling a wingsuit base jumper's speed

    Fgravity = m*g Ffriction = k*A*v^2 Ftotal = Fgravity - Ffriction a = Ftotal/m v = v+a*dt if t<7 then Fgravity>Ffriction if 7<t<67 then v =55,88 (meters per second) if t>67 then A = 45 (square meter) if t>67 then Fgravity<Ffriction the t defines the seconds the first 7 seconds are the free fall...
  30. Mikkel

    Python Numerical modeling of a glacier's length -- Coding error(s)

    Hey Physics Forum I am currently doing my bachelor project in geophysics, with focus on the evolution of glaciers in Greenland. My project consists partly of programming, because I want to get better at it. I have, however, hit a wall. I can't seem to figure out what is wrong with my code and I...
  31. J

    Comp Sci Modeling the queues at a college restaurant

    So far, I have implemented the code below, using Java Priority Queues and Maps. I tried to identify each customer by the time they came in (ranging from 360 and onwards) and their grades. However, this is my first time using priority queues and maps, and I am not very sure if I'm doing things...
  32. J

    Modeling the populations of foxes and rabbits given a baseline

    From solving the characteristic equations, I got that ##\lambda = 0.5 \pm 1.5i##. Since using either value yields the same answer, let ##\lambda = 0.5 - 1.5i##. Then from solving the system for the eigenvector, I get that the eigenvector is ##{i}\choose{1.5}##. Hence the complex solution is...
  33. V

    Ts = temperature of steamModel Boiler: Negative Rate of Change of Enthalpy

    hello, I have dynamically modeled a drum boiler, but when i am solving the equation i am getting an negative rate of change of enthalpythe reason i find is the enthalpy of the steam is very higher than the enthalpy of water. can someone please verify the model and help me with this...
  34. CrosisBH

    [Computational Physics] Modeling the path of a Baseball with drag

    import matplotlib.pyplot as plt import numpy as np #constants and conditions initial_velocity = 49.1744 #m/s, book has 110mph velocity_angle = 35 * np.pi / 180 #coverted to radians because numpy only likes radians gravity = 9.8 #m/s^2 dt=0.1 windspeed = 4.4704 #m/s book has 10mph #calculating...
  35. O

    Analytical mathematical modeling of the torque caused by the laundry

    Hello my dear physicists, I'm trying to model the varied generated (needed)Torque to rotate a washing machine Drum during a Washing Process so i assumed that the Model has as Input the target vilocity and as an Output the new needed torque to rotate the Drum(to be as a input for the motor...
  36. V

    Mathematical Modeling of an evaporator for evaporating water

    I am trying to model an evaporator which evaporates water to steam in Matlab/simulink. Are there any governing equations i need to know and follow when modelling the evaporator mathematically? Please let me know.
  37. nughii

    Numerical methods for PV modeling

    Input parameter $$I_{pv}= 8.2 A$$ $$I_{o=}9.8 e -8 A$$ $$R_s=0.221 \Omega$$ $$R_p=415.405 \Omega$$ $$a=1.3$$ $$V_t=21177.82 V$$ source (Villalva, Marcelo G. 2009. Comprehensive Approach to Modeling and Simulation of Photovoltaic Arrays. IEEE Transaction On Power Electronics, Vol. 24, No. 5)...
  38. M

    Modeling a ball thrown vertically including drag from air resistance

    So I'm trying to figure out how to model a ball getting thrown vertically with the starting velocity v_0. So I've come up with a differential equation which I'm pretty sure is correct: Where D is a constant. So far so good. My problem is solving this. This is my attempt: And when i do this...
  39. V

    Mathematical modeling of a screw compressor

    I am trying to design a compressor in simulink. the mathematical equations has been modeled. but i just need, is there any relation to find the rate of change of volume with respect to time in compressor. Are there any equations or relations to find the rate of change in volume. As its a...
  40. F

    3D printing software modeling and slicing

    Hello, The first step in 3D printing is the generation of a 3D model using a CAD software. But to be able to print the object, the CAD software is not enough, even if the file is saved in .stl or .obj format, correct? Another software, called the slicer, must then receive the 3D modeling file...
  41. K

    Differential equation problem: Modeling the spread of a rumor on campus

    So this is what I have done: ##f'(t)=k*f(t)*(A-f(t))*(1-sin(\frac{pi*x}{12}))## ##\frac{1}{f(t)*(A-f(t))}=k*(1-sin(\frac{pi*x}{12}))## I see that the left can be written as this (using partial fractions): ##1/A(\frac{1}{f(t)}-\frac{1}{A-f(t)})## And then I take the integral on both sides and...
  42. Gumbrain

    I Help With Simple Orbital Modeling

    I have yet to decide on values for the mass of the fixed object, M, the mass of the moving celestial body, m, the initial velocity, v, and the distance between the two objects, r. I will most definitely decide on a larger mass M because I would like the celestial body to spiral in towards the...
  43. A

    Modeling PWR Core With Spacer Grid

    Hello everyone, i am Ali a PhD scholar i need some help regarding MCNP, i wand to model a pwr core with spacer grid but i don't know how to model spacer grid can anyone help? Regards
  44. IDCS

    A Is an epoch-based approach valid for modeling N-body systems?

    Consider a 3-body Newtonian system with equal masses such that velocity change at a given time epoch for a single body is given by: I am interpreting that if also change per epoch such that say which means as a component. So body state information propagates in a way that one could...
  45. B

    Model Pendulum w/ Damping: Newton's Laws & Rubber Band

    I feel like this is a dumb question, but here goes: I'm trying to model a pendulum with damping. The pendulum is connected to a rubber band (unstretched when the pendulum is vertical) on the right side, and the rubber band is fixed at the other end. How would I go about modeling a rubber band...
  46. ArcHorizon

    What do the symbols in the gas equation represent?

    This was the equation that they showed me. I thought P was for pressure, V for Volume, T for Temperature, R for Gas Constant, and n for the number of moles. Was I correct for the initials?
  47. M

    Do physicists really need to master mathematical modeling?

    Summary: Do physicists really need to master mathematical modeling? Do physicists really need to master mathematical modeling? As far as I know Mathematical modeling is a separate discipline form Physics?
  48. M

    Exploring Meshless Modeling Techniques

    Anybody have experience with it? Is it really meshless or just hiding a mesh generation?