Modelling is the process where scientific models[1] are designed. Models are created from a person that is a professional in his environment and has the know how to write down every specification of the system under study.

The Term "Model"

When taking a look in a common dictionary like Webster’s[3], for instance, it soon becomes clear that the term “model” is of highly ambiguous nature. “Model” is used as description for a social role, archetype, or job in the context of various domains like architecture, design, fashion, cars, statistics, and even zoology.

Even though we want to keep the understanding of this term as broad as possible, it might be obvious that we do not want to establish a community that deals with the brokering of human beings that are presenting the newest fashion on respective events. Therefore, we have to be a little more specific where we make use of the following citations: Models are a representation of either reality or vision that are created for some certain purpose with an intended goal in mind. The reality or vision that a model is representing is sometimes also referred to as “system under study” (SUS). Such an SUS can be of one of three different types: either a physical observable element or phenomena, a digital system that resides in computer memories, or an abstract system that eventually resides only in human brains.

Usually a model is not able to include all aspects of the SUS but can only focus on some of them which is known as the property of reduction. As already indicated above there are two types of models that can be classified according to the actual existence of the SUS that is being modeled. If a model describes already existing SUS in the way they really are – or at least some important aspects of them – we are facing a descriptive model as opposed to a prescriptive or specification model that defines how something not yet existing has to be created. A photography, for instance, is for sure descriptive whereas a construction plan that defines how to actually build a house is prescriptive.

Benefits of models

The creation of models provides several benefits. One gain provided by using a defined modeling language is the possibility to communicate information in an understandable way between people. Another advantage is the concentration on the relevant aspects of a system when creating the model, avoiding to loose oneself in unnecessary details. Further more a model stored on a computer, no matter whether is graphical or textual, conforms to a computable data structure. This means that such models can also be used to run algorithms on the provided information, generating new information.

For instance when the SUS is a house, then one model could show the architectural information (walls, doors, ventilation etc.) while another model could encompass the wiring of the lights and power sockets. These can be used by any architect or technician which knows the used modeling language, allowing to build new rooms or install new lights in the house. Another example, closer to the Open Models Initiative, is the description of the goals of a system (for instance using The i* Method). This allows to understand the motivation of different stakeholders and algorithms can use this information to provide each actor with a list of actors on which he is dependent.

Language Levels

This image describes the major division of the language levels. Modelling languages and modelling methods are aligned in the level 2 tier of the diagram above.
The modelling part - using modelling methods - is situated in the level one tier.

See also

For more information it is recommended to read this paper. Models in Science Entry in the Stanford Encyclopedia

References

[#1] Scientific Modelling on Wikipedia
[#2] Definition of the term model at Websters Online Dictionary
[#3] Open Model Initiative - A Feasibility Study