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 language and Italian language ultimately from Latin , .
Models can be divided into physical models (e.g. a ship model or a fashion model) and abstract models (e.g. a set of mathematical equations describing the workings of the atmosphere for the purpose of weather forecasting). Abstract or are central to philosophy of science.
In scholarly research and applied science, a model should not be confused with a theory: while a model seeks only to represent reality with the purpose of better understanding or predicting the world, a theory is more ambitious in that it claims to be an explanation of reality.
Types of model
Model in specific contexts
As a noun,
model has specific meanings in certain fields, derived from its original meaning of "structural
design or layout":
-
Model (art), a person posing for an artist, e.g. a 15th-century criminal representing the biblical Judas in Leonardo da Vinci's painting The Last Supper
-
Model (person), a person who serves as a template for others to copy, as in a role model, often in the context of advertising commercial products; e.g. the first fashion model, Marie Vernet Worth in 1853, wife of designer Charles Frederick Worth.
-
Model (product), a particular design of a product as displayed in a catalogue or show room (e.g. Ford Model T, an early car model)
-
Model organism a non-human species that is studied to understand biological phenomena in other organisms, e.g. a guinea pig starved of vitamin C to study scurvy, an experiment that would be immoral to conduct on a person
-
Model (mimicry), a species that is mimicked by another species
-
Model (logic), a structure (a set of items, such as natural numbers 1, 2, 3,..., along with mathematical operations such as addition and multiplication, and relations, such as ) that satisfies a given system of (basic truisms), i.e. that satisfies the statements of a given theory
[Chang and Keisler, p. 1]
-
Model (CGI), a mathematical representation of any surface of an object in three dimensions via specialized software
-
Model (MVC), the information-representing internal component of a software, as distinct from its user interface
Physical model
A physical model (most commonly referred to simply as a model but in this context distinguished from a
conceptual model) is a smaller or larger physical representation of an
physical object, person or
system. The object being modelled may be small (e.g., an
atom) or large (e.g., the
Solar System) or life-size (e.g., a fashion model displaying clothes for similarly-built potential customers).
The geometry of the model and the object it represents are often similar in the sense that one is a rescaling of the other. However, in many cases the similarity is only approximate or even intentionally distorted. Sometimes the distortion is systematic, e.g., a fixed scale horizontally and a larger fixed scale vertically when modelling topography to enhance a region's mountains.
An architectural model permits visualization of internal relationships within the structure or external relationships of the structure to the environment. Another use is as a toy.
Instrumented physical models are an effective way of investigating fluid flows for engineering design. Physical models are often coupled with computational fluid dynamics models to optimize the design of equipment and processes. This includes external flow such as around buildings, vehicles, people, or hydraulic structures. Wind tunnel and water tunnel testing is often used for these design efforts. Instrumented physical models can also examine internal flows, for the design of ductwork systems, pollution control equipment, food processing machines, and mixing vessels. Transparent flow models are used in this case to observe the detailed flow phenomenon. These models are scaled in terms of both geometry and important forces, for example, using Froude number or Reynolds number scaling (see Similitude). In the pre-computer era, the UK economy was modelled with the hydraulic model MONIAC, to predict for example the effect of tax rises on employment.
in the Science Museum, London]]
for similarly-built potential buyers]]
![Https://www.nasa.gov/sites/default/files/styles/side_image/public/thumbnails/image/edu_wind_tunnels_1.jpg?itok=pZg9nFzN]]<](/icon/extlink.gif "Https://www.nasa.gov/sites/default/files/styles/side_image/public/thumbnails/image/edu_wind_tunnels_1.jpg?itok=pZg9nFzN]]<")
/div>
Conceptual model
A
conceptual model is a theoretical representation of a system, e.g. a set of mathematical equations attempting to describe the workings of the atmosphere for the purpose of weather forecasting.
It consists of
used to help understand or
simulation a subject the model represents.
Abstract or are central to philosophy of science,[Ibrahim A. Halloun, Modeling Theory in Science Education (2007), p. 36.] Thus, the term refers to models that are formed after a conceptualization or generalization process.
Examples
-
Conceptual model (computer science), an agreed representation of entities and their relationships, to assist in developing software
-
Economic model, a theoretical construct representing economic processes
-
Language model, a probabilistic model of a natural language, used for speech recognition, language generation, and information retrieval
-
Large language models are artificial neural networks used for generative artificial intelligence (AI), e.g. ChatGPT
-
Mathematical model, a description of a system using mathematical concepts and language
-
Statistical model, a mathematical model that usually specifies the relationship between one or more random variables and other non-random variables
-
Model (CGI), a mathematical representation of any surface of an object in three dimensions via specialized software
-
Medical model, a proposed "set of procedures in which all doctors are trained"
-
Mental model, in psychology, an internal representation of external reality
-
Model (logic), a set along with a collection of finitary operations, and relations that are defined on it, satisfying a given collection of axioms
-
Model (MVC), information-representing component of a software, distinct from the user interface (the "view"), both linked by the "controller" component, in the context of the model–view–controller software design
-
Model act, a law drafted centrally to be disseminated and proposed for enactment in multiple independent legislatures
-
Standard model (disambiguation)
Properties of models, according to general model theory
According to Herbert Stachowiak, a model is characterized by at least three properties:
[Herbert Stachowiak: Allgemeine Modelltheorie, 1973, S. 131–133.]
- 1. Mapping
- A model always is a model of something—it is an image or representation of some natural or artificial, existing or imagined original,
- 2. Reduction
- In general, a model will not include all attributes that describe the original but only those that appear relevant to the model's creator or user.
- 3. Pragmatism
- A model does not relate unambiguously to its original. It is intended to work as a replacement for the original
- a) for certain subjects (for whom?)
- b) within a certain time range (when?)
- c) restricted to certain conceptual or physical actions (what for?).
For example, a street map is a model of the actual streets in a city (mapping), showing the course of the streets while leaving out, say, traffic signs and road markings (reduction), made for pedestrians and vehicle drivers for the purpose of finding one's way in the city (pragmatism).
Additional properties have been proposed, like extension and distortion[Thalheim: Towards a Theory of Conceptual Modelling. In: Journal of Universal Computer Science, vol. 16, 2010, no. 20, S. 3120] as well as validity.[Dietrich Dörner: Thought and Design – Research Strategies, Single-case Approach and Methods of Validation. In: E. Frankenberger et al. (eds.): Designers. The Key to Successful Product Development. Springer-Verlag, Berlin et al. 1998, S. 3–11.] The American philosopher Michael Weisberg differentiates between concrete and mathematical models and proposes computer simulations (computational models) as their own class of models.[M. Weisberg: Simulation and Similarity - using models to understand the world. Oxford University Press, New York 2013]
Uses of models
According to Bruce Edmonds, there are at least 5 general uses for models:
-
Prediction: reliably anticipating unknown data, including data within the domain of the training data (interpolation), and outside the domain (extrapolation)
-
Explanation: establishing plausible chains of causality by proposing mechanisms that can explain patterns seen in data
-
Theoretical exposition: discovering or proposing new hypotheses, or refuting existing hypotheses about the behaviour of the system being modelled
-
Description: representing important aspects of the system being modelled
-
Illustration: communicating an idea or explanation
See also
External links
