The Portfolio and the Utilisation Scenarios and the Use Spectra of a Model
A model portfolio consists of use spectra that define the main use of the model as an instrument in applications.
A use spectrum combines a number of utilisation scenarios within model deployment processes.
Instruments such as models are used within a utilisation scenario.
This utilisation defines the functions a model plays within such deployment processes. Models
may serve in several functions. Typically, their utilisation follows stereotypes in dependence on the
community of practice.
The portfolio is a combination of tasks one might have in mind while using instruments. The instrument
or artefact plays a number of functions. We distinguish, for instance, the following functions:
The utilisation function of a model relates the model purpose to a practice
or application cases or application `game' similar to
Wittgenstein's language game (we call it better utilisation case
and is characterised by answering the classical W-questions (Hermagoras of Temnos
defined seven ``circumstances'' as the loci of an issue:
Quis, quid, quando, ubi, cur, quem ad modum, quibus adminiculis
(Who, what, when, where, why, in what way, by what means).
This frame seems to be rediscovered by J. Zachman)
how, when, for which/what or why, at what/which (business use case), etc.
We add to purpose:
application, conventions, custom, exertion, habit, handling, deployment, service, usage, use,
and way of using. The model has a role and plays its behaviour within this application game.
We distinguish, for instance, the following functions:
- Description-prescription function: models as images, figures, standard, opus, exposition, representation, composition, realisation;
It results in creation of models that are used for production of systems.
- Explanation function: models `gestalt', pattern, guidance, type, family or species, original, concept, principle,
It results in new insight into the world of the origins.
- Optimisation-variation function: models as creation, ideal, achievement, probe, article, plan, variant, substitute;
It result in an improvement and adaptation of the origins.
- Verification-validation-testing function: models as sample, schema, specimen, pattern;
It results in an improvement of the one of the subjects considered, in most cases in an improvement of models.
- Reflection-optimisation function: models as creation, design, construction, type, derivative, master piece, product;
This function is typical for mathematical modelling of the world of origins.
- Explorative function: models as result, product, work, art piece, metaphor, paradigm, first edition, style, realisation, artefact;
We are, for instance, using models for learning about origins.
- Hypothetical function: models as copy, release, original form, offshoot, simulation or experiment product;
It is typical for discovery science, e.g. science used for climate research.
- Documentation-visualisation function: models as presentation, figure, illustration, demonstration, explanation, adornment,
A use spectrum of a model
consists of a combination of functions within an application 'game'. Typical use spectra are:
- An explanation spectrum is used for derivation of properties that are valid for the origins that a model represents.
- The development spectrum aims at construction of new instruments. The model is at the same time a blueprint or archetype for the new instrument and an image of the requirements and properties requested.
- An simulation spectrum uses models for prognosis of future processes and future states
or for retrospection of past processes and past state on the basis of explanations and descriptions.
- With the description spectrum a model is uses for description of other origins, for documentation and presentation.
A model is bound to its spectra.
Deployment outside the spectrum may result in wrong results (deployment ban>).
The notion of a model
A model is a well-formed,
adequate and dependable
instrument that represents other origins within some context
based on criteria of adequacy and dependability commonly accepted by its community of practice.
A model has - as an instrument - its background
with a undisputable grounding of the sub-discipline and
with a basis consisting of chosen elements from the sub-discipline.
A model is functioning if it is combined with
A functioning model is effective if it can be successfully deployed according
to its deployment scenarios and its portfolio.
They thus function in the application
scenario ('deployment games').
Some recent papers by B. Thalheim on models and modelling
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