Background in database querying technologies, more specifically XML, JSON, XML Schema, XQuery, JSONiq, XBRL, HDFS, MapReduce, Spark.
Co-designer of Rumble. Co-designer of the open-source JSONiq language, and of the cell store database paradigm (NOLAP). Former member of the XML Query working group at W3C. Author of The XBRL Book, which explains XBRL in details on the technical level to Engineers.