About
Niels Willems is a PhD student in the Visualization group of professor Jack van Wijk at Eindhoven University of Technology. His supervisor is Huub van de Wetering. We are involved in the Poseidon project of the Embedded Systems Institute, which investigates the system evolvability and reliability of systems of systems in favour of Thales Nederland bv and Noldus Information Technology bv. In this project, we focus on visualization of anomalies in maritime safety and security (MSS) systems.
Contact
ir. Niels C.M.E. Willems,
Department of Mathematics and Computer Science, Visualization
group,
Eindhoven University of Technology
Den
Dolech 2, Room HG 5.43 ,
PO Box 513, 5600 MB Eindhoven, The Netherlands
Email: 
(preferred communication, quick response)
Phone: +31 (0)40 247 4344
Secretary: +31 (0)40 247 5010
Research
Visualization of vessel trajectories for maritime safety and security systems
The sea seems an open playground, but regulations hold, and furthermore, safety (collision prevention) and security (thread prevention) need to be ensured. Operators monitor the coast using a Maritime Safety and Security (MSS) system, which allows analysis of multiple heterogeneous data sources. We aim at visualization methods to support operators to react on dangerous situations. To detect abnormal behavior, it has to be known what normal behavior is. As a first step, we start with visual exploration of trajectories of large vessels obtained by the AIS system.
Trajectories are convolved by moving a kernel with the speed of the vessel along the path. We compute the density with both a small and large kernel and show them simultaneously in the shading of a colored height field. The large kernel shows an overview of maritime highways and the small kernel reveals slow moving vessels, which typically occur in zones before the harbour where ships drop anchor.
An interesting location is the entrance of Rotterdam harbour. On the left, earlier work of the Dutch Ministry of Transport is shown where ships observed from an airplane are convolved. The poster is constructed with about 8000 data points during 3 years. On the right, our new method shows millions of data points during one week of shipping movement. The image shows that captains nicely obey the maritime rules.
Interactive visualization in large scale comparative genomics
The genetic material of all organisms (DNA)
is structurally and functionally equivalent. If two organisms share similar
properties (phenotypes), these properties often derive from a common ancestor
and are encoded similarly in the DNA. Comparative genomics is a molecular biological
discipline searching for such similarities between DNA sequences as an indication
of common ancestry and hence, a hint of similar function.
The number of similarities between DNA sequences may be enormous and chaotically
distributed. Besides, on large scale, individual similarities might be negligible
small, but can be part of a much larger similarity.
A large set of similarities between DNA sequences of Arabidopsis thaliana is hierachically clustered using various
distance measurements [Jin et al, 2006; Vanderpoele, 2002] to enable visualization
using bundles [Holten, 2006]. The result is an overview of dense locations
of similarities, which current tools have problems to visualize. The overview
of similarities can interactively be manipulated using the interactive DNAVis2 genome browser.
References
Danny Holten. Hierarchical edge bundles: Visualization of adjacency relations in hierarchical data. IEEE Transactions on Visualization and Computer Graphics, 12(5):741-748, 2006.
Hee-Jeong Jin, Hye-Jung Kim, Jeong-Hyeon Choi, and Hwan-Gue Cho. Alignscope: A visual mining tool for gene team finding with whole genome alignment. Advances in Bioinformatics & Computational Biology, February 2006.
Klaas Vandepoele, Yvan Saeysa, Cedric Simillion, Jeroen Raes, and Yves Van de Peer. The automatic detection of homologous regions (adhore) and its application to microcolinearity between Arabidopsis and rice. Genome Research, 12(11):1792-1801, November 2002.
Publications
- Multivariate trajectory selection, Niels Willems, Huub van de Wetering, and Jarke J. van Wijk, Workshop on Behaviour Monitoring and Interpretation, 2009
- Vessel density, Niels Willems, Huub van de Wetering, and Jarke J. van Wijk, Workshop on Behaviour Monitoring and Interpretation, 2009
- Visualization of vessel movements,
Niels Willems, Huub van de Wetering, and Jarke J. van Wijk, Computer Graphics Forum (Proceedings of EuroVis 2009), vol. 28, no. 3, p. 959-966, 2009.
- Visualization of vessel trajectories
for maritime safety and security systems, Niels Willems, Huub van de Wetering, and Jarke J. van Wijk, IEEE InfoVis 2008, 2008
- Visualization of vessel trajectories
for maritime safety and security systems, Niels Willems, Huub van de Wetering, Jarke J. van Wijk, and Hans Hiemstra, SIREN2008, 2008
- Interactive visualization in large scale comparative genomics, Niels Willems,
Master's thesis, Eindhoven University of Technology, 2007.
Color map: Journal, Conference, Workshop, Thesis, and Miscellaneous.
An extended list of activities.
