A context model (or context modeling) defines how context data are structured and maintained (It plays a key role in supporting efficient context management). It aims to produce a formal or semi-formal description of the context information that is present in a context-aware system. In other words, the context is the surrounding element for the system, and a model provides the mathematical interface and a behavioral description of the surrounding environment. It is used to represent the reusable context information of the components (The top level classes consist of

Operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

, component container, hardware requirement and

Software Software is a set of computer programs and associated software documentation, documentation and data (computing), data. This is in contrast to Computer hardware, hardware, from which the system is built and which actually performs the work. ...

requirement). A key role of context model is to simplify and introduce greater structure into the task of developing context-aware applications.

Examples of context models

The

Unified Modeling Language 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 m ...

as used in systems engineering defines a context model as the physical scope of the system being designed, which could include the user as well as the environment and other actors. A

system context diagram A system context diagram (SCD) in engineering is a diagram that defines the boundary between the system, or part of a system, and its environment, showing the entities that interact with it. This diagram is a high level view of a system. It is sim ...

represents the context graphically.. Several examples of context models occur under other domains. * In the situation of parsing a

grammar In linguistics, the grammar of a natural language is its set of structural constraints on speakers' or writers' composition of clauses, phrases, and words. The term can also refer to the study of such constraints, a field that includes domain ...

, a context model defines the surrounding text of a lexical element. This enables a context sensitive grammar that can have deterministic or stochastic rules. In the latter case, a

hidden Markov model A hidden Markov model (HMM) is a statistical Markov model in which the system being modeled is assumed to be a Markov process — call it X — with unobservable ("''hidden''") states. As part of the definition, HMM requires that there be an o ...

can provide the probabilities for the surrounding context.Klein, Dan, and Christopher D. (2002) Manning.
"A generative constituent-context model for improved grammar induction."
In Proceedings of the 40th Annual Meeting on Association for Computational Linguistics, pp. 128-135. Association for Computational Linguistics. * A context model can also apply to the surrounding elements in a

gene sequence In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

. Like the context rules of a grammar disambiguating a lexical element, this helps to disambiguate the role of the gene. * Within an

ontology In metaphysics, ontology is the philosophical study of being, as well as related concepts such as existence, becoming, and reality. Ontology addresses questions like how entities are grouped into categories and which of these entities exi ...

, a context model provides disambiguation of a subject via semantic analysis of information related to the subject. * In terms of a physical environment, a context model defines the external interfaces that a system will interact with. This type of context model has been used to create models for

virtual environment A virtual environment is a networked application that allows a user to interact with both the computing environment and the work of other users. Email, chat Chat or chats may refer to: Communication * Conversation, particularly casual * Onlin ...

s such as the

Adaptive Vehicle Make Adaptive Vehicle Make was a portfolio of programs overseen by DARPA, of the United States Department of Defense. AVM attempted to address revolutionary approaches to the design, verification, and manufacturing of complex defense systems and vehicle ...

program. A context model used during design defines land, aquatic, or atmospheric characteristics (stated in terms of mathematical algorithms or a simulation) that the eventual product will face in the real environment. Component, Context, and Manufacturing Model Library – 2 (C2M2L-2)
Broad Agency Announcement, DARPA-BAA-12-30, February 24, 2012

References

{{reflist Systems analysis