What is Modelling: Definition and 286 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. D

    Modelling non ideal apparatus in quantum mechanics

    THe EQUATIONS IN THIS POST HAVE NOT GONE THROUGH SO WILL TRY TO FIX THIS AND RE SUBMIT ASAP (I used mathType?) Now attached the post as a word file to fix the above. I’m playing around with possibilities and my own ideas about “the measurement problem” and have a query about the validity...
  2. R

    How to Derive the Output Equation from State-Space Models?

    Hello. I have some trouble solving this exercise. For this given linear system: with the input Tm(T) described by these equations or re-written this way It's also suggested that the states should be considered this way resulting I have to find out the state-space model (A,B,C,D...
  3. O

    Modelling a Falling Slinky w/ Lagrangian

    Homework Statement Hi everyone! This is not actually a homework problem, but I thought it was similar to one so I am putting it here. Basically I was watching this youtube video of a falling slinky and I decided I wanted to try modelling it with physical equations: The problem I have...
  4. T

    Can anyone explain the basics of 3D heat transfer modelling?

    Hi, I need to model heat transfer in a 3D digital environment. I have very little physics / engineering background so I have no idea what's available or what software / methods are used. I have some background in CAD and general experience in Matlab, but this is going to be a steep learning...
  5. B

    Mathematical Modelling question

    Though this question is about medicine, the actual question has little to do with medicine and more to do with modelling .. Homework Statement A patient is put on an intravenous drip at time t=0, the drip supplies a drug into the patients bloodstream at a constant rate λ. At the same time...
  6. R

    Modelling non linear springs in abaqus

    Dear, First i modeled linear springs with abaqus: Model >> Assembly >> Engineering Features >> Springs/Dashpots >> Connect two points, In this way i can define just only the spring stiffness. So therefore i would like to define a non linear springs. I used the connecter builder >>...
  7. C

    Modelling the spread of disease (in MatLab, Runge-Kutta)

    Homework Statement Hi! I'm to build a model which solves the basic dynamic eqns in the so called SIR model in epidemology. I'm using MatLab and RK4. There are tree populations in this model: Succeptible S, infected I and recovered R. Homework Equations The eqations are dS/dt =...
  8. K

    Equilibrium solutions in mathematical modelling

    Hi, I don't want to list the exact problem I have to solve, as I would rather do it myself, all I would like is some guidance. The problem is a function like: Pk+1=a (Pk-1) with a few more constants and some brackets thrown about on the right hand side. I need to find all the equilibrium...
  9. P

    Modelling an Exponential Curve

    Hi guys, I need to model a curve and I am trying to come up with an exponential equation. I have several points I can work with and this is what I tried so far. (I want to know if this is the correct method or if there is a more precise way to go about this) I am working on something of the...
  10. A

    Time dependent PDEs - mathematical modelling - diffusion equation

    Homework Statement Porous membranes are used to separate mixtures in industry, because smaller compounds permeate through them more easily than larger ones. KnoGas Pty Ltd are trialling an experimental separation process, using a membrane to sep- arate compounds A and B: compound A...
  11. wukunlin

    Modelling Varactor Diode BB201 for FM Transmitter Design

    modelling a varactor [solved] Homework Statement basically I'm designing a fm transmitter, the master oscillator uses a varacter for modulation the varactor diode we are given is the BB201, i have attached the spec sheet in this post. a spice model is also given for this diode: [.MODEL...
  12. F

    Engineering  Modeling Optima 300 Brushless DC Motor 2208-1100KV

    This is not homework but I would consider it to fall in this category. I am working on a robotics project and wanted to simulate a PID controller before implementation. I need to find a transfer function for my motor for this to work. Homework Statement As mentioned above, I need to find...
  13. A

    Gravity modelling of asteroid 433 Eros. Any help will be appreciated.

    Hello. I am an engineering student and i am attempting to model the gravity around the asteroid Eros by expanding the potential as a spherical harmonic expansion. I got the coefficients (Clm and Slm) from the Planetary Data Model of Eros(NEAR Collected Shape and Gravity Models available at...
  14. C

    Questions about modelling a sensor with a target wheel in Maxwell

    Hi everyone, I need to model a crank sensor with a flying wheel in Maxwell. Crank sensor is made of permenant magnet, pole piece (to concentrate the magnetic field), and coil. There is a space between the target wheel and the crank the sensor. What I have to do is to simulate the output...
  15. MattRob

    Modelling Charged Particle Flow

    I'm working on something right now where I want to model the flow of an electrically charged gas (hydrogen) reacting to an electrostatically charged metal grid. I know, more or less nothing about this type of mechanics, so I want to create a model using a simple programming language, with a...
  16. F

    Creating Two Coils with Different Axes on Comsol 3.5

    Hi, I am trying to create two coils with different axes on Comsol Multiphysics 3.5. I use the 2D axisymetric mode but it allows to create only coils with the same axe. Can somebody help me ? Thanks in advance.
  17. D

    Finding default unit vectors in 3D modelling

    When you are modelling elements like tubes, the local x-axis is defined along the tubes length. If a unit vector for the z-axis is not applied, modelling softwares defaults to a coordinate system where the local zx-plane is parallel with the global zx-plane. I'm not sure what that means...
  18. R

    Anti de Sitter space modelling

    * Anti de Sitter space is used in the AdS/CFT conjecture. But the universe is composed of de Sitter space. So not*use de Sitter space?* If only*AdS can work in the model, and it's not even representative of our universe, then it may be just wrong. *
  19. C

    Thermal Modelling: Ansys for Temperature Distribution in Structures

    Hi everyone. I want to find out thermal gradient (or temperature distribution) in a structure subjected to multiple mediums at different temperature. Would Ansys be the right tool for it, or can you suggest one? Would the methodology be to draft the structure in a simulation software first...
  20. E

    Can Non-Newtonian Fluids Predict Pole (De)acceleration in Oobleck?

    Here is the problem. I drop a pole (say length L, mass M, radius R) on a non-Newtonian fluid (corn starch and water) with impact velocity v. The density and viscosity of the oobleck is known, and I know the dimensions of the oobleck container (a square box of length S filled up to height H...
  21. S

    Mathematica modelling question

    I'm kinda of messing around with a model of a biological system, I've found the equilibriums and decided I'd get the stability relations as well. I tried using mathematica to get the eigenvalues of the system to see if its stable or not and when I got the eigenvalues of my matrix mathematica...
  22. D

    Modelling system at early design stage

    Hello, nice to find this kind of great forum. I am quite puzzled with the task that was given to me: How to model mechatronical system (multidomain) on early product development stage? So, because product is not well defined yet, there are much uncertainties what to model(!) So, how to...
  23. A

    Modelling gravitational force vectors

    Modelling Density as a Function of Many Objects Hello, My question is somewhat difficult to express but this is the best way I can come up with. Lets say I have a mass of material which has a charge throughout its entirety. This material has a very special property where the density of the...
  24. A

    Brayton Cycle modelling - optimum system design

    Hi I am trying to model the Brayton cycle in a gas turbine that is used for electricity generation. My main aim is to be able to fully power the x amount of daily electricity load of a building using this machine. In order to do this, is it correct to do a backwards model and find what...
  25. P

    What are the coefficients for a 1KW wind turbine?

    Homework Statement Model a 1KW windturbine. Homework Equations in this link u will find the equation (its equation 2-3) for a fit for a cp(lambda,beta) curve. It has 6 coefficients. The coefficients given are particular to a 1.5 MW windturbine. Does anyone know where I can find any...
  26. T

    Can Salome handle pulse jet physics for CFD simulation?

    I've been intrigued lately by pulse jet engines and their simplicity. Unfortunately, they are notoriously loud and inefficient. I've come up with a design that I think may improve both of those, but before trying to actually build it, I thought it would be a good idea to try to model it first...
  27. A

    Interested in Mathematical Modelling? How Can You Specialize in Energy Systems?

    Hi I will like some advice. I intend to know more about mathematical modelling. Can anyone recommend any useful books, websites of software? How does one develop an interest in it? I will like to specialise in the modelling of energy systems and not sure how to do it. Please advise
  28. Z

    Is modelling REALLY impossible in quantum mechanics?

    I am not a physicist, so please excuse the gaps in my knowledge. I am writing a would-be philosophical essay about models in different fields of research. In most general terms, my task is to consider how modelling can be useful in the pursuit of knowledge in the widest understanding of the...
  29. P

    A good book on Mathematical modelling

    i want to learn how to use experimental data to produce effective mathematical model for good prediction of any phenomenon. my mathematical background is : i know about single and multivariable calculus,college algebra,introductory probability theory,trigonometry,vector algebra and calculus,and...
  30. B

    Modelling a short square-wave pulse with Telegrapher's Equation

    I am interested in looking at the voltage component of a short (possibly nanosecond width) pulse in a coaxial cable along the cable at a given distance, Z, along the line. I am "cheating" by using the steady state Telegrapher's equation [Eq. 1] and formulating a periodic pulse approximation. It...
  31. J

    Engine Modelling in Simulink

    Homework Statement I am modelling an engine, I have attached a picture of my model. It is the basic engine model that comes with Simulink, with my attachments included. My question is, how and where do I enter my own values? I'm pretty new to using Simulink, so I don't really know where...
  32. G

    Modeling Solar Heat Transfer in Storage Tank: Tips & Equations

    We have a model where we are to predict the temperature of the water outlet stream of a storage tank. Basically we have a solar heating collector that heats up a fluid which is present in a storage tank. The flow process is that the fluid flows through the pipes to the solar collector and back...
  33. T

    Modelling Motion (Angular Speed etc.)

    [PLAIN]http://img198.imageshack.us/img198/6579/mechanics2.jpg I've done the first bit (showing x and \dot{x} are always perpendicular) but how do I show that the motion lies in a plane? Also, how do I do the final part?
  34. S

    Modelling simulation for 6g shock

    Hi all, I am a student designing a camera fixture for my senior design project. We are halfway through our project right now and we are trying to do some validation stuff for our fixture. One of the requirements for our fixture is for it to withstand 6 g's of shock during...
  35. M

    Ball and socket joint FSI modelling

    Hello all, Just would like to some input from the engineering world on this. I would like to model the lubrication film between a ball and socket joint using FE/CFD co-simulations. In reality the ball and socket arrangement would be located in a bath of fluid and the fluid would provide...
  36. M

    Abaqus Modelling - Troubleshooting Tutorial for Beginners

    Hello ! I'm a beginner in Abaqus and for that I've tried to follow this tutorial http://fliiby.com/file/831535/i3rkmyhurs.html . I was all ok until I tried to make the mesh (chapter 3.7.2 in tutorial). It said that they are parts of the assemby that are too complex to be meshed with those...
  37. H

    Modelling Car Impact: Predicting Obstacle Movement and Displacement

    I am trying to model the following situation: Let say i have an obstacle with known mass, and I know the coefficient of static and dynamic friction between the obstacle material and the floor. A car traveling at a fixed velocity is to impact the obstacle. For simplicity i will first consider...
  38. J

    Modelling a vacuum pipe using an orthogonal material

    Hi! I'm trying to model a vacuum pipe on Ansys. I've already modeled it using an isotropic material, assuming its a plane strain problem (infinate pipe), but now I want to use a laminate structure composed of an orthogonal material such as nomex (honeycomb) with a seal tight layer of Al or...
  39. T

    Applied and Pure mathematics with focus on modelling

    Hi, I am in need of some expert advice please. I am enrolling for my honours degree in mathematics next year. I am trying to mix it up in order to have a strong foundation in pure mathematics with specialisation in applied mathematics. My interests are financial mathematics, probability...
  40. C

    Numerical modelling of electrostatic potential energy of a system

    Hi there, Lately, I've been trying to gain a deeper understanding of the relationship between the Coulomb force F, electric field E, electric potential V, and electrostatic potential energy U. In regards to electrostatic potential energy, as I understand it, if you had, say (made up a few...
  41. E

    Modelling DE mixture problem

    Homework Statement A solution of material A of concentration C0 kg/m3 flows into a tank at the flow rate F m3/min. The tank has fixed volume V m3 and is continuously stirred. The solution on the tank is of concentration C and flows out the top of the tank at the flow rate F. The material A...
  42. C

    Modelling forces acting on a sail

    Hi all. I'd like to create a basic model of the forces acting on a sail (wind sail, like a tail ship) A couple of things I was thinking about: 1) can create a very simple model where wind is 'one' force acting on the a uniform body. 2) model wind as vectors. This is where I am a little...
  43. T

    Differential equations help, modelling population

    in a scientific study, the size , p of a population at t hours is being studied. Initially p = 560 and after 6 hours, p is found to be 1218. In a simple model of population growth, the rate of the population is taken to be proportional to the population at that time. Using this model predict...
  44. I

    New to Pro/E Modelling - Creating a Crane Arm

    Greetings Engineers I am relatively new to pro/e modelling. Most of the solids I have created till date using pro/e have been simple ones using mostly the extrude or revolve tool. I am presented with a problem as I try to create a more complex model of a crane arm ( similar to the arm in -...
  45. A

    Solving for Car Depreciation: Linear, Quadratic, and Exponential Models

    Homework Statement A car depreciates over time. x(years) y ($) 1 14000 2 9100 3 6200 4 4000 5 3000 i) determine the linear model (1 mark) ii) determine the quadratic model (1 mark) iii) determine the...
  46. S

    Fully Pay Off Your Home Loan in Record Time: ODE Modeling Question Solution

    Homework Statement A college graduate borrows $100,000 at an interest rate of 9% to buy a house. The college graduate plans to make payments at a monthly rate of 800(1+t/120), t is the number of months since the loan was made. Assuming this payment schedule can be maintained, when will the loan...
  47. C

    Modelling probability spaces

    measure spaces and random variable are still fuzzy to me although I'm starting to see how random variable are s used, i need some clarification on the following suppose we have a random variable X we don't know what the exact sample space is but say we know the density is f_{X}(x) , x...
  48. Z

    Predicting Output Voltage Using Small Signal Diode Model

    small signal diode modelling i understand what it is but when i get asked a question like: if vin(t)=2.5+cos(2*pi*100*t) for 0<t<30 use the small signal model of the diode to predict the output voltage of the circuit i have added. assume the opamp is ideal R=2000 Is=10e-16 so i know...
  49. J

    How to Use Euler's Method to Approximate Velocity in a Quarter Circle Motion

    I have an assigned project in Physics with numerical modeling, to which I am supposed to use Euler's method to approximate the velocity of a "mass sliding down a frictionless in the shape of a quarter circle of radius 2.00 m." The assignment also states: "Do three trials: t = 0.2s, t = 0.02s...
  50. M

    Modelling an Aeroplane - Non-Linear Differential Equation

    Hi everyone, Homework Statement I've been having a bit of trouble with my mathematics coursework. We have to model an aeroplane that has just landed with two equations. One prior to braking, one after. I've used a model with a quadratic drag approximation; and I'm not certain if my result...
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