“Data Semantics in the Days of Big Data” (2015)
John Mylopoulos holds a professor emeritus position at the Universities of Trento and Toronto. He earned a PhD degree from Princeton University in 1970 and joined the Department of Computer Science at the University of Toronto that year. His research interests include conceptual modelling, requirements engineering, data semantics and knowledge management. Mylopoulos is a fellow of the Association for the Advancement of Artificial Intelligence (AAAI) and the Royal Society of Canada (Academy of Sciences). He has served as programme/general chair of international conferences in Artificial Intelligence, Databases and Software Engineering, including IJCAI (1991), Requirements Engineering (1997), and VLDB (2004). Mylopoulos is the recipient of an advanced grant from the European Research Council for a project titled "Lucretius: Foundations for Software Evolution”.
In the good old days, the semantics of data was defined in terms of entities and relationships. For example, a tuple (widget:w#123, price: €10, date: 1970.07.30) in the SALES relation meant something like “widget w#123 was sold for €10 on July 30, 1970”. This simple view of semantics no longer applies in the days of big data, where gigabytes of data are pouring in every day and the intended meaning is defined in terms of strategic objectives such as “We want to grow our sales by 2% over three years”, or tactical ones such as “We want to grow sales for our clothing products by 2.5% over the next quarter in Lombardia”. We review some of the elements of this new perspective on data and present some of the analysis techniques that are emerging along with big data technologies.