This paper describes an ontology for enterprise modelling, The ontology has enabled conceptual integration of two different modelling methodologies, one based on UEML (Unified Enterprise Modelling Language), the other a UML profile for enterprise modelling for software development. The ontology, called Model-based Architecture Framework for Enterprises (MAFE), extends a general framework for model based architectures (MAF). It contains a minimal number of core concepts, which were found to be designated by numerous different terms in the two pre-existing methodologies.
Concepts can be categorised according to logical strength (ability to express facts precisely) into indefinite individuals, definite individuals, classes, relations and quantitative properties. Over the lifecycle of a model, all of these concept categories may appear, typically evolving from vague concepts towards increased logical strength.
Conceptual models must be able to cater for all of these degrees of vagueness and
precision. Perspective integration [
MAFE is a refinement of MAF. Whereas MAF covers any kind of system, MAFE focuses on the specific kind of systems called ‘enterprise’, defined as a project, undertaking or business activity. The conceptual model of MAFE is a refines that of MAF. All MAFE models contain terms that designate MAFE concepts, which are depicted in Figure 1. • Enterprise is an undertaking. It is the system of analysis for an enterprise model. It contains other enterprise elements. • Task is a unit of work at any level of granularity or specificity. Terms like action, process, activity, work item etc. typically designate different kinds of tasks. Such term reflect different points of view, and are thus terms, not concepts. • Resource is anything needed to perform work. Resource is actually a point of view on objects that primarily exist as something else, e.g. persons, documents, and things. Resources are specialised depending on their role − Actor, the active subjects that perform the work, (humans or computers). − Information, objects that bring knowledge to the process. − Tool, objects applied by the actor to perform the work. − Object, material things that are manipulated or applied in the work. In addition to these resources, Knowledge, Time and Money are also important for an enterprise. These aspects are intertwined with the resources, e.g. determining availability. • Decision, a choice among alternatives. A decision may also include e.g. the identification and exploration of alternatives, and the timing of selections. • Dependency is the general kind of association between enterprise elements.
Among tasks, dependencies capture sequencing and coordination needs, while dependencies between tasks and resources entail that the resources are applied for performing the task. Two important dependencies are defined. Fills relates an element and a resource, signifying that one takes the role that the other specifies, while Flow signifies that something should occur before the other something else. • Goal (from MAF), representing visions, objectives, goals of actors, tasks, enterprises etc.
SystemElement
(from MAF) +DependsOn *
* Enterprise Element
Goal (from MAF) has Dependency
Task
Decision
Resource
System (from IEEE1471)
Enterprise
Money Knowledge
Person Fills
Flow
Actor
Information
Object
Tool
All of these objects may be decomposed into objects of any kind. For instance, a dependency may be decomposed into a process of tasks that manage this dependency, and a resource may be decomposed into a decision tree that articulates which actors may fill the role.
MEML is a modelling notation for the concepts described above. MEML has roots in
data flow diagrams, which was extended with resource modelling and control flow
semantics in APM [
Like MAFE is a specialisation of MAF for enterprise architectures, so is MAFIS for information systems. The environment viewpoint in MAFIS describes what surrounds the information system, including a number of enterprise elements. MAFIS was developed for a particular purpose in a government agency. We were able to define all the enterprise terms in MAFIS with MAFE concepts. An example (from organisation modelling) is shown in the table below (with MAF and MAFE concepts in italic). By defining MAFIS terms (model element classes) in this way, we were thus able to align the UML profile with a standard enterprise modelling language. In a similar manner, we were also able to show that the enterprise viewpoint terminology of ISO RM-ODP (Reference model for open distributed processing [9]) also designates MAFE concepts.
Organisation unit Parent_organisation Structural relationship
Composite Actor Decomposition of Actor Dependency between Actors 3
We are now completing the operationalisation of the MAFE methodology. The
metametamodel structure and services is of particular concern in this work, since it
controls how users may define new concepts, terms, modelling elements and views
needed in their local domain. In general, we are concerned about how modelling can
be made more user-friendly and less computer-oriented, allowing different degrees of
formalisation. Towards this aim, we have found reflective instances (containing their
own definition) to be a promising approach, removing much of the complexity of
class-oriented approaches. To make the framework comprehensible, we seek to
minimise the number of meta-layers, offering the users templates that they may copy
rather than classes to instantiate. Finally, computer-oriented encapsulation, where the
behavioural semantics of each class is defined inside the class and hidden from the
rest of the model, is replaced by semantic holism, where the meaning of each model
element may depend on the whole rest of the model. This approach better mimics the
flexibility, contextuality, simplicity and expressive efficiency of natural language [