A metamodel 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 branch of both computer science and engineering focused on designing, developing, testing, and maintaining Application software, software applications. It involves applying engineering design process, engineering principl ...

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 uti ...

. 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 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 and Italian ultimately from Latin , . Models can be divided in ...

is an abstraction of phenomena in the real world; a metamodel is yet another abstraction, highlighting the 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 networks,

Kriging In statistics, originally in geostatistics, kriging or Kriging (), also known as Gaussian process regression, is a method of interpolation based on Gaussian process governed by prior covariances. Under suitable assumptions of the prior, kriging g ...

, 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 the right metamodels to represent that behavior. Common uses for metamodels are: * As a

schema Schema may refer to: Science and technology * SCHEMA (bioinformatics), an algorithm used in protein engineering * Schema (genetic algorithms), a set of programs or bit strings that have some genotypic similarity * Schema.org, a web markup vocab ...

for

semantic Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction betwee ...

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" and ...

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 a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

, and has practical applications in

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

and

computer engineering Computer engineering (CE, CoE, or CpE) is a branch of engineering specialized in developing computer hardware and software. It integrates several fields of electrical engineering, electronics engineering and computer science. Computer engi ...

. The latter are the main focus of this article.

Topics

DoDAF Perspectives and Decomposition Levels

Definition

, the use of

s is an alternative to more common code-based development techniques. A model always conforms to a unique metamodel. One of the currently most active branches of

Model Driven Engineering Model-driven engineering (MDE) is a software development methodology that focuses on creating and exploiting domain models, which are conceptual models of all the topics related to a specific problem. Hence, it highlights and aims at abstract r ...

is the approach named

model-driven architecture Model-driven architecture (MDA) is a software design approach for the development of software systems. It provides a set of guidelines for the structuring of specifications, which are expressed as models. Model Driven Architecture is a kind of doma ...

proposed by OMG. This approach is embodied in the

Meta Object Facility The Meta-Object Facility (MOF) is an Object Management Group (OMG) standard for model-driven engineering. Its purpose is to provide a type system for entities in the CORBA architecture and a set of interfaces through which those types can be creat ...

(MOF) specification. Typical metamodelling specifications proposed by OMG are UML, SysML, SPEM or CWM.

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

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 (so ...

. 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, constructio ...

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. It may be applied as part of broader Model-driven engineering (MDE) concept. Overview Data modeli ...

Model transformations

One important move in

model-driven engineering Model-driven engineering (MDE) is a software development methodology that focuses on creating and exploiting domain models, which are conceptual model (computer science), conceptual models of all the topics related to a specific problem. Hence, i ...

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 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 ...

, Tefkat, MT, ManyDesigns Portofino.

Relationship to ontologies

Meta-models are closely related to

ontologies In information science, an ontology encompasses a representation, formal naming, and definitions of the categories, properties, and relations between the concepts, data, or entities that pertain to one, many, or all domains of discourse. More ...

. 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 or universe of discourse (borrowing from the mathematical concept of ''universe'') is the set of entities over which certain variables of interest in some formal treatment may range. It is also ...

by utilizing 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 Kermeta is a modeling and programming language for metamodel engineering. History The Kermeta language was initiated by Franck Fleurey in 2005 within thTriskellteam of IRISA (gathering researchers of the INRIA, CNRS, INSA and the University of ...

) * Model transformation language (see below) * Polynomial metamodels *

Neural network A neural network is a group of interconnected units called neurons that send signals to one another. Neurons can be either biological cells or signal pathways. While individual neurons are simple, many of them together in a network can perfor ...

metamodels *

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

CASE Case or CASE may refer to: Instances * Instantiation (disambiguation), a realization of a concept, theme, or design * Special case, an instance that differs in a certain way from others of the type Containers * Case (goods), a package of relate ...

tool.