A metamodel or surrogate model is a model of a model, and metamodeling is the process of generating such metamodels. Thus metamodeling or meta-modeling is the analysis, construction and development of the frames, rules, constraints, models and theories applicable and useful for modeling a predefined class of problems. As its name implies, this concept applies the notions of meta- and modeling in software engineering and

systems engineering Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their enterprise life cycle, life cycles. At its core, systems engineering util ...

. Metamodels are of many types and have diverse applications.

Overview

A metamodel/ surrogate model is a model of the model, i.e. a simplified model of an actual model of a circuit, system, or software like entity. Metamodel can be a mathematical relation or algorithm representing input and output relations. A model is an abstraction of phenomena in the real world; a metamodel is yet another abstraction, highlighting properties of the model itself. A model conforms to its metamodel in the way that a computer program conforms to the grammar of the programming language in which it is written. Various types of metamodels include polynomial equations, neural network, Kriging, etc. "Metamodeling" is the construction of a collection of "concepts" (things, terms, etc.) within a certain domain. Metamodeling typically involves studying the output and input relationships and then fitting right metamodels to represent that behavior. Common uses for metamodels are: * As a schema for

semantic Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference, meaning, or truth. The term can be used to refer to subfields of several distinct disciplines, including philosophy, linguistics and comput ...

data that needs to be exchanged or stored * As a language that supports a particular method or process * As a language to express additional semantics of existing information * As a mechanism to create tools that work with a broad class of models at run time * As a schema for modeling and automatically exploring sentences of a language with applications to automated test synthesis * As an approximation of a higher-fidelity model for use when reducing time, cost, or computational effort is necessary Because of the "meta" character of metamodeling, both the praxis and theory of metamodels are of relevance to metascience, metaphilosophy, metatheories and

systemics In the context of systems science and systems philosophy, systemics is an initiative to study systems. It is an attempt at developing logical, mathematical, engineering and philosophical paradigms and frameworks in which physical, technological, ...

, and meta-consciousness. The concept can be useful in

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

, and has practical applications in computer science and

computer engineering Computer engineering (CoE or CpE) is a branch of electrical engineering and computer science that integrates several fields of computer science and electronic engineering required to develop computer hardware and software. Computer engineers ...

/ software engineering. The latter are the main focus of this article.

Topics

DoDAF Perspectives and Decomposition Levels

Definition

In software engineering, the use of models is an alternative to more common code-based development techniques. A model always conforms to a unique metamodel. One of the currently most active branch of Model Driven Engineering is the approach named model-driven architecture proposed by

OMG OMG may refer to: * Oh my God (sometimes also Oh my Goodness or Oh my Gosh), a common abbreviation, often used in SMS messages and Internet communication Acronyms * OMG is the IATA code for Omega Airport, Omega, Namibia * Operational manoeuvre ...

. This approach is based on the utilization of a language to write metamodels called the Meta Object Facility or MOF. Typical metamodels proposed by

are

UML The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system. The creation of UML was originally ...

, SysML, SPEM or CWM. ISO has also published the standard metamodel ISO/IEC 24744. All the languages presented below could be defined as MOF metamodels.

Metadata modeling

Metadata modeling is a type of metamodeling used in software engineering and

for the analysis and construction of models applicable and useful to some predefined class of problems. (see also:

data modeling Data modeling in software engineering is the process of creating a data model for an information system by applying certain formal techniques. Overview Data modeling is a process used to define and analyze data requirements needed to suppo ...

Model transformations

One important move in model-driven engineering is the systematic use of model transformation languages. The OMG has proposed a standard for this called QVT for Queries/Views/Transformations. QVT is based on the meta-object facility (MOF). Among many other model transformation languages (MTLs), some examples of implementations of this standard are AndroMDA, VIATRA, Tefkat, MT, ManyDesigns Portofino.

Relationship to ontologies

Meta-models are closely related to ontologies. Both are often used to describe and analyze the relations between concepts * Ontologies: express something meaningful within a specified universe or

domain of discourse In the formal sciences, the domain of discourse, also called the universe of discourse, universal set, or simply universe, is the set of entities over which certain variables of interest in some formal treatment may range. Overview The domain ...

by utilizing a grammar for using vocabulary. The grammar specifies what it means to be a well-formed statement, assertion, query, etc. (formal constraints) on how terms in the ontology’s controlled vocabulary can be used together. * Meta-modeling: can be considered as an ''explicit'' description (constructs and rules) of how a domain-specific model is built. In particular, this comprises a formalized specification of the domain-specific notations. Typically, metamodels are – and always should follow - a strict rule set. "A valid metamodel is an ontology, but not all ontologies are modeled ''explicitly'' as metamodels".

Types of metamodels

For software engineering, several ''types'' of models (and their corresponding modeling activities) can be distinguished: * Metadata modeling (MetaData model) * Meta-process modeling (MetaProcess model) *Executable meta-modeling (combining both of the above and much more, as in the general purpose tool Kermeta) * Model transformation language (see below) * Polynomial metamodels *

Neural network A neural network is a network or circuit of biological neurons, or, in a modern sense, an artificial neural network, composed of artificial neurons or nodes. Thus, a neural network is either a biological neural network, made up of biological ...

metamodels * Kriging metamodels * Piecewise polynomial (spline) metamodels * Gradient-enhanced kriging (GEK)

Zoos of metamodels

A library of similar metamodels has been called a Zoo of metamodels. There are several types of meta-model zoos.AtlanticZoo
. Some are expressed in ECore. Others are written in MOF 1.4 – XMI 1.2. The metamodels expressed in

- XMI1.2 may be uploaded in Poseidon for UML, a

CASE Case or CASE may refer to: Containers * Case (goods), a package of related merchandise * Cartridge case or casing, a firearm cartridge component * Bookcase, a piece of furniture used to store books * Briefcase or attaché case, a narrow box to c ...

tool.