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
Context awareness refers, in information and communication technologies, to a capability to take into account the ''situation'' of ''entities'', which may be users or devices, but are not limited to those. ''Location'' is only the most obvious el ...
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 daemon (computing), services for computer programs.
Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
, 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 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 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 structure, structural constraints on speakers' or writers' composition of clause (linguistics), clauses, phrases, and words. The term can also refer to the study of such constraint ...
, a context model defines the surrounding text of a
lexical element. This enables a
context sensitive grammar
A context-sensitive grammar (CSG) is a formal grammar in which the left-hand sides and right-hand sides of any production rules may be surrounded by a context of terminal and nonterminal symbols. Context-sensitive grammars are more general than ...
that can have
deterministic or
stochastic rules. In the latter case, a
hidden Markov model 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. 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 ...
, 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 environments such as the
Adaptive Vehicle Make 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)](_blank)
Broad Agency Announcement, DARPA-BAA-12-30, February 24, 2012
References
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Systems analysis