Ontology in the Modern Computer Era

For decades, the concept of ontology has been daunting in literature. Many misconceptions exist regarding its definition. In this paper, these confusions are cleared up. A unified definition or understanding of ontology is established, which also helps to distinguish ontology, work, and work domain. Indeed, prior to the emergence of the computer, ontology is related to physics and philosophy, which does not have much confusion. Now, in the era of modern computers and informatics, ontology is connected to the computer along with the computer's language or data (information and knowledge), which leads to confusion, as now ontology is across the human and computer. The fundamental reason for the confusion is the lack of understanding of this change, in particular the relationship between ontology and data model. This paper establishes this relationship, which makes it possible to define the so-called data model of ontology (or ontology model for short), and further to define the data model of work and the data model of the work domain. Finally, this paper examines data modelling techniques for ontology modelling, work modelling, and work domain modelling. Throughout this paper, healthcare systems are used to facilitate discussions.