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 Software engineering is a systematic engineering approach to software development. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term '' ...

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 The word schema comes from the Greek word ('), which means ''shape'', or more generally, ''plan''. The plural is ('). In English, both ''schemas'' and ''schemata'' are used as plural forms. Schema may refer to: Science and technology * 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 Praxis may refer to: Philosophy and religion * Praxis (process), the process by which a theory, lesson, or skill is enacted, practised, embodied, or realised * Praxis model, a way of doing theology * Praxis (Byzantine Rite), the practice of fai ...

and theory of metamodels are of relevance to

metascience Metascience (also known as meta-research) is the use of scientific methodology to study science itself. Metascience seeks to increase the quality of scientific research while reducing inefficiency. It is also known as "''research on research''" ...

metaphilosophy Metaphilosophy, sometimes called the philosophy of philosophy, is "the investigation of the nature of philosophy". Its subject matter includes the aims of philosophy, the boundaries of philosophy, and its methods. Thus, while philosophy character ...

, 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 Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...

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 ...

. The latter are the main focus of this article.

Topics

DoDAF Perspectives and Decomposition Levels

Definition

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

SysML The Systems Modeling Language (SysML) is a general-purpose modeling language for systems engineering applications. It supports the specification, analysis, design, verification and validation of a broad range of systems and systems-of-systems. S ...

, SPEM or CWM.

ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...

has also published the standard metamodel

ISO/IEC 24744 ISO/IEC 24744 ''Software Engineering — Metamodel for Development Methodologies'' is an ISO/IEC standard for software engineering metamodelling for development methodologies. It defines a metamodel from which development methodologies (sof ...

. All the languages presented below could be defined as MOF metamodels.

Metadata modeling

Metadata modeling Metadata modeling is a type of metamodeling used in software engineering and systems engineering for the analysis and construction of models applicable to and useful for some predefined class of problems. Meta-modeling is the analysis, construction ...

is a type of metamodeling used in

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 QVT (Query/View/Transformation) is a standard set of languages for model transformation defined by the Object Management Group. Overview Model transformation is a key technique used in model-driven architecture. As the name QVT indicates, the ...

for Queries/Views/Transformations.

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 VIATRA is an open-source model transformation framework based on the Eclipse Modeling Framework (EMF) and hosted by the Eclipse Foundation. VIATRA supports the development of model transformations with specific focus on event-driven, reactive t ...

Tefkat Tefkat is a model transformation language and a model transformation engine. The language is based on F-logic and the theory of stratified logic programs. The engine is an Eclipse plug-in for the Eclipse Modeling Framework (EMF). History Tef ...

, 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 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 metamodel In mathematics, a polynomial is an expression consisting of indeterminates (also called variables) and coefficients, that involves only the operations of addition, subtraction, multiplication, and positive-integer powers of variables. An example ...

s *

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 In mathematics, a piecewise-defined function (also called a piecewise function, a hybrid function, or definition by cases) is a function defined by multiple sub-functions, where each sub-function applies to a different interval in the domain. Pi ...

Gradient-enhanced kriging Gradient-enhanced kriging (GEK) is a surrogate modeling technique used in engineering. A surrogate model (alternatively known as a metamodel, response surface or emulator) is a prediction of the output of an expensive computer code. This predi ...

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

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.