+49 261 287-2775
When I passed my PhD in Koblenz, my colleagues gave my a t-shirt that summarizes my research interests. On it was written "Everything is a Network". My research interests indeed follow these lines:
- Analysis of small and large networks
- I created the Koblenz Network Collection (KONECT) in order to have enough datasets to make significant research. KONECT is a collection of 180+ networks, and a Matlab toolbox for their analysis. I use KONECT for most of my research on networks. KONECT is growing constantly due to contributions from other researchers.
- Spectral and algebraic graph theory
- I have done much work on representing graphs as matrices and using the decomposition of these matrices to get insights on the graphs. My PhD thesis was about the use of graph matrix decompositions in link prediction. The main result of my PhD thesis is the Spectral Evolution Model.
- I showed how split-complex numbers can be used to model relationships on dating websites
- Modeling of complex networks
- More recently, I have become interested in probabilistic models of networks, with the goal to have models that (1) Are realistic, as can be verified by using KONECT data, and (2) Which scale to large sizes.
- I have introduced new measures of inequality, diversity, preferential attachment and bipartivity.
- Graphs with special structure
- I started my academic career with work on the Laplacian matrix for signed graphs. Later, I published one of the first online social network dataset with positive and negative edges: the Slashdot Zoo. On a higher level, I found out whether negative links are even necessary in social networks.
- I analysed more exotic matrix decompositions for directed networks.
- I analysed the special properties of bipartite networks.
- One of my long term research goal is to formulate a model of semantic networks
Other interests of me include:
- Web Science
- Beside being part of the Institute for Web Science and Technologies at the University of Koblenz–Landau, I have been involved with the organization of the Web Science Conference and related Web Science workshops, and am also involved on multiple projects in which aspects of social sciences play a role. I have also been present on the Web Science conference roster since 2011.
- Interestingness on Twitter
- Tensor decomposition and joint diagonalization