Sjir Nijssen, PNA Group, Netherlands


“Durable Modeling and Ever Changing Implementation Technologies” (2015)


Short bio:


Dr. Sjir Nijssen is emeritus and has been CTO at PNA in the Netherlands ( for the last 25 years. Dr. Nijssen first experienced the essential steps of working with facts in 1959 and 1960 while serving as a draft officer in the Royal Dutch Air Force, where at that time careful observation of planes of friends and enemies by boys on towers in the field, and girls plotting the information by the boys in one of the seven areas of the Netherlands, over telephone lines on a large table in atomic free bunkers. The contents of the tables of the seven areas was verbalized by girls sitting at the next higher level and were then plotted by girls in the central command on a table covering the entire Netherlands. That information was used by the officers to direct interceptor planes. This was a world with very clear protocols how to observe, how to formulate the facts, how to convert the facts into another representation of the facts on a land map table, verbalizing the information of the local tables into facts and transmit these facts to the girls plotting the information read on the central table. Dr. Nijssen started with fact based business communication modeling in the early seventies, at Control Data’s European headquarters in Brussels.


Since then it has been more than his full-time occupation. It was there where NIAM (Natural language Information Analysis Method), a fact based protocol to develop a conceptual schema  and notation, was conceived. Prof. Robert Meersman was one of the pillars of the 22-person research lab at Control Data, from 1970-1982.  Since 1983 Dr Nijssen held  a position as professor of Computer Science for seven years at the University of Queensland in Australia. In 1989 he founded the company PNA , exclusively dedicated to delivering durable and tested business requirements, conceptual modelling, consulting and educational services fully based on fact orientation. PNA currently employs about 30 people. Dr. Nijssen can be reached directly at sjir.nijssen(at)




In the relative short history of Information Technology we have seen substantial improvements. However between the wishes of the users and the implemented services there is still in many cases an enormous gap. And the problem of very substantial costs overruns in the development of these services is still in too many cases a serious challenge. These days we aim to fill this gap between the requirements and the running services with what is called a durable model. The road towards a durable model has been a long one and an overview will be given since the sixties. During the seventies and eighties the term conceptual model was used to refer to a durable model, with many contributions from the IFIP WG 2.6 conferences and the landmark publication of the ISO Technical Report TR9007 in 1987, Concepts and Terminology for the Conceptual Schema and the Information Base. Thereafter we discuss how durable modeling has evolved and misused by various factions in the research and business world.


Since 2012 a co-creation has been established in The Netherlands consisting of government services organizations, universities and innovative companies with the aim to develop an engineering protocol how to “transform” laws, regulations and policies into a durable model. The aim is to develop a national protocol that will be offered to all government departments and all other organizations in The Netherlands. Of course it will be offered to the world. We will discuss the scientific foundation of this protocol, called CogniLex, as well as it’s practical version and report on experiences obtained so far. To the best of our knowledge this is the most extensive protocol currently available. The skills of protocolled observation and transformation into facts, transforming the facts into another representation mode adequate for a specific purpose and transforming the other representation mode back into verbalized facts are vital parts of any testing protocol, called ex-ante in Terra Legis. We will demonstrate how certain legal domain protocol essentials like Hohfeld can be modeled in Fact Based Modeling, a durable modeling approach. We will also demonstrate how Fact Based Modeling has been used to detect the needed extensions to the famous work of Hohfeld. If time permits the transformation of such a durable model into UML, ER, OWL, SBVR and DMN will be discussed.