Personalia
Harold van Heerde graduated in February 2006 at the University of Twente on a thesis named "Life-Cycle Privacy Policies for the Ambient Intelligence", where he had been reading Computer Science since 2000. Prior to that he visited the Zuyderzee College in Emmeloord, where he attented the 'VWO'. His extra-curricular activities included the chairman-ship of the board of the IAPC-foundation.
Harold received his PhD degree on the 4th of June, 2010, after participating in the NWO-VIDI and BRICKS funded project "Towards Context-Aware Data Management for Ambient Intelligence", which has been supervised by Prof. Dr. Peter Apers in close coorperation with the SMIS team of INRIA Rocquencourt in France. Having started in March 2006, his main area of research focused on Privacy-aware Data Management. His thesis can be found here.
As from March 2010, Harold worked as a consultant information technology at Witteveen+Bos. Witteveen+Bos offers its clients value-added consultancy and top-quality designs for water, infrastructure, spatial development, environment and construction projects.
In April 2013, Harold left Witteveen+Bos and started Irias information management together with his associate Jeroen Nijhuis. Irias focuses on data integration, data analysis, and data-as-a-service. They combine technical know-how with concultancy skills, making it possible to quickly identify and fulfill their customer needs with innovative solutions.
In his free time Harold enjoyes sporting (football, cycling, jogging, squash, skiing et cetera), photography, and reading. Since 2006 he again participates in the board of IAPC, which he left again in 2009.
Privacy-aware data management by means of data degradation
Service-providers collect more and more privacy-sensitive information, even though it is hard to protect this information against hackers, abuse of weak privacy policies, negligence, and malicious database administrators. In my thesis, we take the position that endless retention of privacy-sensitive information will inevitably lead to unauthorized data-disclosure. Limiting the retention of privacy-sensitive information limits the amount of stored data and therefore the impact of such a disclosure.
A problem of limited retention is that the retention period is often overstated in advantage of the service-provider. We model the interests of service-provider and user in an abstract, qualitative way; when such a model is quantitatively specified, it is possible to calculate the optimal retention period for the joint interest of service-provider and user. The all-or-nothing behavior of limited retention is too rigorous: the data will be completely destroyed, also destroying any possible use of the data. Progressively degrading a data item instead of removing the data item in one single step makes it possible to balance the interests of service-provider and user better than limited retention can do. At every degradation step, the precision of a data item will be decreased. Degraded data is supposed to be less privacy-sensitive, and still usable enough to motivate a longer storage.
However, removing data from a database system is not a straightforward task; data degradation has an impact on the storage structure, indexing, transaction management, and logging mechanisms. To show the feasibility of data degradation, we provide several techniques to implement it; mainly, a combination of keeping data sorted on degradation time and using encryption techniques where possible. The techniques are founded with a prototype implementation and a theoretical analysis.
Finally, we explore several models which build further on the basic data degradation model. This gives different perspectives from which data degradation can be used.
2014
2010
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2006
2005
Awards
- CTIT Symposium poster competition 2006, 2nd price, http://www.ctit.utwente.nl/news/archive/2006/may2006/awards2006.doc/. [Poster][Abstract]
Master students
- Arend-Jan Tetteroo, Bomb-proof Server, Technolution
- Pim Sierhuis, Het voorkomen van prestatieverlies bij de koppeling met Web services, Huijsmans & Kuijpers Automatiseringsbureau
- Mark Olthof, Performance & Scalability of a Spatial Database in a GIS-Webservice Environment, LogicaCMG
- Hugo Siles Del Castillo, Hybrid Content-Based Collaborative-Filtering Music Recommendations, University of Twente
- Sven Mathijssen, Feasibility study for implementing life-cycle policies in an RDBMS, University of Twente
- Michel Kruiskamp, FastSOA: Achieving High-Performance Service Oriented Architectures, Logica Arnhem