Economic Models - Convex Optimization

122 Nikitas Spiros Koutsoukis
2. Model and Enterprise Terminology
Model and enterprise are the two key terms that appear throughout this
paper. An enterprise can be perceived as “a set of concurrent processes executed
on the enterprise means (resources or functional entities) according
to the enterprise objectives and subject to business or external constraints”
(Vernadat, 1996). A model can be defined as “a structure that a system
can use to simulate or anticipate the behaviour of something else” (Hoyte,
1992). This is a generalization of a definition given by Minsky (1968):
“a model is a useful representation of some subject. It is a (more or less
formal) abstraction of a reality (or universe of discourse) expressed in terms
of some formalism (or language) defined by modeling constructs for the
purpose of the user”.
Instead of attempting to form a definition, which may be redundant, we
will mention some important features of enterprise models instead.
• An enterprise model provides a computational representation of the
structure, activities, processes, information, resources, people, behavior,
goals, and constraints of a business, government, or other enterprise.
It can be both descriptive and definitional-spanning what is and what
should be. The role of an enterprise model is to achieve model-driven
enterprise design, analysis, and operation (Fox, 1993).
• Enterprise models must either be represented in the mind of human beings
or in computers (Christensen et al., 1995).
• All enterprise models are built with a particular purpose in mind. Depending
on the purpose, the model will emphasize different types of information
at different levels of detail.
3. Enterprise Modeling
During the last decades, EM has been partly addressed by several
approaches to the same problem of making the enterprise more efficient.All
these approaches have included the construction of symbolic representations
of aspects of the real world, using various notations and techniques that
commonly could be denoted “conceptual modeling” (Solvberg and Kung,
1993). The idea of EM, as an extension of the standard for the exchange
of product model data (STEP) product modeling approach, contributes to
integrating design (which focuses on product information) and construction
(focusing on activity and resource information) (Kemmerer, 1999).