Dr. Walther Dirk from Dresden University of Technology, Germany, paid a two-week visit to JLU for academic exchange activities, invited by Zhang Rui from CCST. The visit was funded by the training program by Department of International Affairs of JLU for young scholars. Dr. Dirk Walther gave a lecture Seeking Practical Algorithms to Calculate EL-TBoxes Logical Difference on Nov. 3, 2015.

Dr. Dirk Walther obtained his PhD in computer science at University of Liverpool in 2007 before staying engaged in postdoctoral research till 2009. He was a researcher of Juan de la Cierva in Technical University of Madrid, Spain in 2010 and served as an associate researcher at the cfAED project at the Dresden University Technology, Germany. Dr. Walther is a PC member of IJCAI, AAAI, AAMAS and many other famous international conference. He lectured on two courses of Module in Ontology and Logical Difference in Ontology in European Summer School in Logic, Language and Information (ESSLLI) respectively in 2013 and 2014. In computer science and information science, an ontology formally represents knowledge as a set of concepts within a domain, and the relationships between those concepts. Ontology construction and maintenance require ontology version control to manage different versions of the same ontology. The logical difference concept proposed in 2008 can more accurately reflect the semantic differences between different versions of ontology. The logical difference between EL terminologies has been solved, but the algorithm to calculate the TBox EL logical difference is still unknown. In the lecture, Dr. Walther reported the latest research results and expressed his willingness to discuss with the teachers and students in the following two weeks. Teachers and students from Mathematics School and CCST attended the lecture.