As of 1 November, CWI researcher Peter Grünwald has been appointed Professor Statistical Learning at the Mathematical Institute of Leiden University.
This chair allows the university to expand its expertise in this rapidly developing field. Grünwald holds this position for one day a week and will, among others, set up a class in Statistical Learning.
Statistical learning theory is about learning from data (finding patterns) with as few assumptions about reality as possible. Suppose scientists expect a connection between age and blood pressure. To establish this they take measurements from a number of people. Next they try and draw a graph in the best possible way. Often a linear relation is assumed. One takes the straight line that best connects the designated points. A more ambitious approach would be to postulate a quadratic or exponential relation, each with their own graphs. T But what if researchers lack prior knowledge and do not really know what kind of graph to draw? Grünwald researches how scientists can still (automatically) make a choice.
Grünwald’s mathematics also has applications in computer science, for instance, a self-learning spam filter: there the relation is sought between the contents of an email and whether it is wanted or unwanted (spam). A spam filter should learn, from a collection of emails, which emails are unwanted, without an explicit indication from the user. Another example of self-learning capabilities can be found in speech recognition software. In computer science, this discipline is called Computational Learning.
Grünwald’s chair is part of an exchange programme with Professor Richard Gill, who will do research at CWI for one day a week. Gill is known to the general public as the organiser of a petition to reopen the case against Lucia de B. This petition followed a letter from Gill and Grünwald to the Committee Evaluation Closed Criminal Cases, in which they argued that imperfect statistics played an important part in the conviction.
Number of people on Earth
How many people have ever been born on Earth? That is the prize-winning question of magazine Quest, December 2008. Peter Grünwald estimated the amount: 107.5 billion. See Quest's press release (in Dutch).
