Professor Sebastian Link
DSc (Auckland 2015); PhD (Massey 2005); MSc (Clausthal 2000)
I received my PhD in Information Systems from Massey University in 2005. Then I was lecturing in Information Systems at Massey University, Palmerston North, until 2007. From 2008 until 2011, I was Associate Professor at the School of Information Management at the Victoria University of Wellington. In 2012, I joined the Department of Computer Science at the University of Auckland. I was awarded a Doctor of Science degree from the University of Auckland in 2015.
Research | Current
My main research interest is data management. My contributions include new concepts and frameworks for the control of entity and referential integrity in databases, database design on the logical and physical level, data cleaning, data mining, and data profiling. This research applies to different models of data, such as relational databases, databases with missing information, SQL and Web databases, probabilistic and possibilistic databases. More specifically, I have introduced notions such as possible and certain keys, embedded uniqueness constraints, probabilistic keys, possibilistic keys, keys for property graphs, possible and certain functional functional dependencies, embedded functional dependencies, NOT NULL inclusion dependencies, keys and functional dependencies for XML, as well as multivalued and hierarchical dependencies for various data models, and have established axiomatic and low-degree polynomial algorithmic characterizations for their associated implication problem. I have extensively worked on structural and computational properties of perfect samples (Armstrong databases) for these and other classes of data dependencies. I have also developed various algorithms for the discovery problems associated with some of these classes. For example, Ziheng Wei and I established a new state-of-the-art algorithm for the discovery problem of functional dependencies. Recently, I have established various database schema design frameworks, including SQL, data-completeness tailored database design, and schema design for applications with uncertain data. I have also helped introduce the concept of non-invasive data cleansing.
Teaching | Current
SOFTENG 351 - Fundamentals of Database Systems
COMPSCI752 - Big Data Management
Wei, Ziheng (PhD) - Robust data profiling and database schema design for data with missing values
Roblot, Tania (PhD) - Probabilistic cardinality constraints
Memari, Mozhgan (PhD) - Partial referential integrity in relational databases
Le, Van (PhD) - On the discovery of semantically meaningful functional dependencies in SQL: Foundations, implementation and evaluation
He, Senyang (MSc) - Discovery of possibilistic functional dependencies
Litvinenko, Ilya (MSc) - Visualizing the semantics of uncertain data in possibilistic SQL tables
Liu, Bo (MSc) - Validation of application semantics with XML Schema
Zhang, Lin (MSc) - Learning conjunctive SQL queries by example
Brown, Pieta (MProf) - Probabilistic keys
Tham, Wai Loong (MProf) - Visualizing the New Zealand web topology
Cahan, Casey (MProf) - Prediction of rugby injuries from training data sets
I received the Chris Wallace Award for outstanding research contributions to Australia and New Zealand in 2013, awarded by the Computing Research and Education Association of Australasia (CORE). This is the most prestigious award for mid-career computer scientists in Australasia. The prize is available to academics for post-PhD research undertaken in a university or research institution in Australia or New Zealand. The research must include a notable breakthrough or contribution of particular significance. At most one award is made each year.
I was co-chair of the technical program committee for the following international conferences:
the 25th International Conference on Database and Expert System Applications (DEXA) to be held from 1-5 September 2014 in Munich, Germany
the 24th International Conference on Database and Expert System Applications (DEXA) held from 26-30 August 2013 in Prague, Czech Republic
the Sixth International Conference on Scalable Uncertainty Management held from 17-19 September 2012 in Marburg, Germany.
the Seventh Asia-Pacific Conference on Conceptual Modeling (APCCM) held from 18-21 January 2009 in Brisbane, Australia.
the Sixth International Symposium on Information and Knowledge Systems (FoIKS) held from 14-19 February 2010 in Sofia, Bulgaria.
the Sixth Asia-Pacific Conference on Conceptual Modeling (APCCM) held from 20-23 January 2009 in Wellington, New Zealand.
Currently, I am an editorial board member of the journals Information Systems, Data & Knowledge Engineering, and Proceedings of the VLDB Endowment.
I am a key individual on the Endevour grant Tikanga in Technology: Indigenous approaches to transforming data ecosystems, led by Maui Hudson from the University of Waikato. The grant is funded by the Ministry of Business, Innovation, and Employment for NZD7m from 2020-2024.
I am a key researcher on a NZ Data Science Research Programme on Deep Data Science, funded by the Ministry of Business, Innovation, and Employment with NZD10m from 2020-2027. I am leading the meta-data science theme.
I was an associate investigator in Miika Hannula's Marsden Fast-start project Dependence Logic and its Application, from Government funding, administered by the Royal Society of New Zealand. The grant was for NZD 300,000 from 2017-2019.
I was a partner investigator in the project A user-centric approach towards data quality management, funded by the Nature Science Foundation of China (NSFC). The administrative university was Soochow University in Suzhou, China. The grant was for NZD 160,000 from 2014-2017.
I am the contact principal investigator for the Full Marsden Research grant on Constraints on SQL data: Foundations for a data-intensive society from Government funding, administered by the Royal Society of New Zealand. The grant was for NZD 405,000 from 2012-2014.
I was the contact principal investigator for the Full Marsden Research grant on Cardinality constraints for XML: Challenging the Trade-off between Expressiveness and Tractability from Government funding, administered by the Royal Society of New Zealand. The grant was for NZD 400,000 from 2009-2011.
I was the sole investigator for the Fast-Start Marsden Research grant on Investigating complex-value database design problems using Brouwerian algebras from Government funding, administered by the Royal Society of New Zealand. The grant was for NZD 140,000 in 2006 and 2007.
As Associate Dean International, I have helped establish and run several transnational educational programmes, such as
- A joint undergraduate, and a joint Master programme in Data Science with Beijing Institute of Technology, China
- A university-level dual PhD agreement framework with Beijing Institute of Technology, China
- A joint undergraduate programme in Data Science with Southwest University, China
- AULIN joint college with Northeast Forestry University, China, with joint undergraduate programmes in Biotechnology, Chemistry, and Computer Science, and a dual Master programme in Ecology.
Associate Dean (International) - Faculty of Science
Founding Director of Data Science programmes:
- three year Undergraduate Major
- one year full-time Master of Professional Studies in data science
- one and a half year Master of Data Science
- two year Master of Data Science
Areas of expertise
Artificial intelligence, Database design, Database security, Database theory, Data managment, Data modeling, Data science, Logic in Computer Science, Semantics in data, Uncertainty in data, Web databases
Selected publications and creative works (Research Outputs)
- Wei, Z., Hartmann, S., & Link, S. (2020). Discovery Algorithms for Embedded Functional Dependencies. Proceedings of the ACM SIGMOD International Conference on Management of Data. 10.1145/3318464.3389786
- Balamuralikrishna, N., Jiang, Y., Koehler, H., Leck, U., Link, S., & Prade, H. (2019). Possibilistic keys. FUZZY SETS AND SYSTEMS, 376, 1-36. 10.1016/j.fss.2019.01.008
- Wei, Z., Leck, U., & Link, S. (2019). Discovery and ranking of embedded uniqueness constraints. Proceedings of the VLDB Endowment, 12 (13), 2339-2352. 10.14778/3358701.3358703
- Link, S., & Prade, H. (2019). Relational database schema design for uncertain data. INFORMATION SYSTEMS, 84, 88-110. 10.1016/j.is.2019.04.003
- Wei, Z., & Link, S. (2019). Embedded Functional Dependencies and Data-completeness Tailored Database Design. Proceedings of the VLDB Endowment (PVLDB), 12 (11), 1458-1470. 10.14778/3342263.3342626
- Wei, Z., & Link, S. (2019). Discovery and Ranking of Functional Dependencies. Paper presented at IEEE 35th International Conference on Data Engineering (ICDE), Macau, PEOPLES R CHINA. 8 April - 11 April 2019. 2019 IEEE 35TH INTERNATIONAL CONFERENCE ON DATA ENGINEERING (ICDE 2019). (pp. 12). 10.1109/ICDE.2019.00137
- Roblot, T., Hannula, M., & Link, S. (2018). Probabilistic Cardinality Constraints: Validation, Reasoning, and Semantic Summaries. VLDB JOURNAL, 27 (6), 771-795. 10.1007/s00778-018-0511-z
- Köhler H, & Link, S. (2018). SQL schema design: foundations, normal forms, and normalization. Information Systems, 76, 88-113. 10.1016/j.is.2018.04.001