A formalism for object-based information systems development

Most current approaches to Information Systems Development (ISD) tend to derive from past experience and practice, rules of thumb and technology trends. The lack of theoretical foundations hinders the systematic development and evaluation of new ISD methodologies. The research undertaken in this thesis addresses this issue by proposing a formal, theory-based model, Ontology/Object-Based Conceptual Modelling (OBCM), for conceptually representing IS applications. The formalism is novel in that it is grounded in first principles derived from metaphysics, in particular the system of Ontology developed by Mario Bunge. Underlying this approach is the premise that an Information System is a model of reality and that model should be therefore rooted in a theory of reality, ie. a metaphysics. As a result, basic assumptions in reality such as thing, substance, property, attribute, time, state and change are explicitly and rigorously addressed. OBCM features an ontologically well-defined construct, "object", which is used to directly represent entities in reality, thus lending theoretical credence to the so-called object-oriented paradigm found in recent programming languages and databases. In addition, the thesis presents a framework, Ontology/Object-Based Information System (OBIS), for systems implementation based on this model. This framework directly implements the object construct so that it can be immediately utilized by the information systems user in a "direct manipulation" style of end-user interaction. Further, OBIS strives for a single, homogeneous concept of system operation drawn from ontology rather than in terms of IS or computing technology. In principle, this one concept can be applied to any object in the IS, this simplifying the understanding and use of the Information System. In this way, the model attempts to unify the analysis, implementation and user-interface aspects of Information Systems Development, thereby reducing the so-called "semantic gap" which has often been observed between the reality of the application and its final implementation in an IS. A "proof of concept" prototype is described which illustrates the main principles and explores practical applications of the proposed model. This prototype is implemented as a single, stand-alone "shell" which can be used to support a wide variety of applications as well as providing the basis of a rapid prototyping or CASE tool. The prototype is used to implement sample problems including the well-known IFIP Working Conference problem, thus demonstrating the feasibility of the overall approach.Business, Sauder School ofGraduat