Information Technology Reference
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to each other. Data models provide structure to digital data inside of the computer.
Information models relate data models and conceptual models, thereby providing
meaning to digital data.
4.2 Concepts for Modeling the UoD
The knowledge, which is represented in an information system, is entirely con-
ceptual. The data, which are stored and processed by an information system, are
linguistic units, which denote concepts and referents in the Universe of Discourse
[ 18] . The linguistic units are represented by digital numbers. Concepts are grouped
differently depending on users' needs. Linguistic concepts are different from facts
and ideas. Information systems are concerned with data that represent facts in a
Universe of Discourse. A fact is what is known -or assumed- to belong to reality. In
science and technology one usually distinguishes the following kinds of facts: state,
event, process, phenomenon, and concrete system e.g., a magnetic field [5] . Ideas
are formally expressed as concepts, formulas (e.g., statements) and theories, which
are systems of formulas. Conceptual models are the formal expressions of ideas.
Conceptual modeling in computer based information systems are most often
concerned with phenomena where it becomes important to distinguish among indi-
viduals, and to deal with classifications of individuals, e.g., the concept of PERSON
represents all persons, dead, living and unborn. Set theory is well suited to deal with
discrete phenomena. This makes set theory to be well suited to deal with digital
representations of facts. The relevant modeling ontology reflects the properties of
mathematical set theory and is thus of considerable generality.
Unfortunately set theory is less suited to deal with phenomena of continuous
nature. For example, take the concept of copper. Copper is part of bronze and it
is part of brass. It feels somewhat artificial to view copper as a class concept, its
extension being all things of copper [ 5] .
4.2.1 Conceptual Modeling of Non-Discrete Phenomena
The deficiencies of set theory may be counteracted by introducing mereology -
the theory of parthood relations - as a mathematical foundation of similar impor-
tance as set theory, see [ 45] . This makes possible within a respectable mathematical
framework, the alternative, but still similar, classification of facts which is found in
the American National Standard's guidelines for thesauri construction [ 1] , which
recommends that distinction is made among the following kinds of concepts
(non-exhaustive list):
things and their physical parts, e.g. bird, car, mountain;
materials, e.g., water, steel, oxygen;
activities or processes, e.g., painting, golf;
events or occurrences, e.g., birthday, war, revolution;
properties or states of persons, things, materials or actions, e.g., elasticity, speed;
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