## Lustrumsymposium

Graag nodigen we jullie allen uit om het inspirerende lustrumsymposium bij te wonen. Het symposium vindt plaats op zaterdag 9 juni op het universiteitsterrein in gebouw Waaier, zaal 4 en zal starten met de inloop met koffie & lekkers om 10.30 uur.

Als dagvoorzitter hebben we Michel Vellekoop zo ver gekregen om jullie op 9 juni door deze dag te leiden.

**Biografie:** Michel Vellekoop werd geboren in de Bollenstreek maar trok voor zijn studie naar het Oosten: hij liep van 1989 tot en met 1994 rond in het TWRC-gebouw als student bij Applied Mathematics, dat toen nog Toegepaste Wiskunde (TW) heette. Na het behalen van zijn Mastertitel trok hij weer naar het Westen voor promotie-onderzoek aan het Imperial College in Londen, waar hij zich bezig hield met niet-lineaire filterproblemen voor stochastische processen. In 1998 kwam Michel terug naar de Universiteit Twente om als assistant professor (UD) onderzoek te doen op het gebied van de financiële wiskunde en om samen met Arun Bagchi een nieuwe afstudeervariant in die richting op te zetten. In die tijd was hij ook actief binnen WSG Abacus, bijvoorbeeld tijdens twee bestuurstermijnen als Algemeen Adjunct (1998-99 en 1999-2000). In 2009 vertrok hij weer westwaarts en werd benoemd tot hoogleraar aan de Universiteit van Amsterdam op het gebied van Actuarial Science & Mathematical Finance.

## Het programma

10.55u Opening door Joost Kok, decaan van EWI

Joost Kok is an expert in the field of processing and analysing data. He helps scientists to develop new treatments, aids the government in discovering potential fraudulent health insurance claims and advises the Ministry of Transport on monitoring the condition of bridges from a distance.Medicine, psychology, music, sport, traffic, share trading: these are but some of the many fields that collect and analyse large quantities of data (numbers, text, images, graphics, audio and much more) in order to achieve their goals. Big data is everywhere. Joost Kok: ‘Take large supermarket chains, for example. They register countless factors in their stores: the temperature, when and how many people look happy, and so on.

Computers use this kind of data to calculate what a manager can change in the store in order to sell as much as possible.’ IBM estimates that 2.3 trillion gigabytes of data (business and private) are created worldwide each day. ‘Processing, analysing and making this data findable ̶ what is known as data science ̶ throws up all sorts of challenges,’ Kok explains.

‘To begin with, all the data you have collected can contain errors. What can you do about that? There are also limits to the capacity of the computers that need to store the data and make the calculations necessary to analyse it. The main thing is to ensure that the computer calculations are as smart as possible. What we do is battle the complexity of data and try to link different types of data, such as images and text.’

11.00u Presentatie Nelly Litvak (Universiteit Twente)

**Title:** The friendship paradox: why my friends have more friends than I do

**Abstract: **My research is about large networks, such as Internet, social networks and networks of bank transactions. A network consists of objects (for example, people) connected by some relations (for example, friendships). Networks are very interesting to study because they are full of unexpected results and paradoxes. The friendship paradox is a famous, by now classical, example. Do you sometimes have this feeling that your friends are more popular than you are? Well, most probably, this feeling is right! It turns out that on average, your friends have more friends than you do. Fortunately, this says nothing about your social skills. This is merely how the math works. I will explain the friendship paradox and tell you how it can be exploited to sample from networks that are not available to us.

**Biography:** Nelly Litvak is professor in Algorithms for Complex Networks and has a background in Applied Probability and Stochastic Operations Research. She works on mathematical methods and algorithms for complex networks, such as social networks and the WWW. Real-life networks are modeled as random graphs, and algorithms are used to extract information from the massive network data. The overall goal of her research is to extract value from (Big) Data, focusing on network data. Her research revolves around three main topics: Information extraction and predictions based on data, mathematical analysis of network characteristics and randomized algorithms. The first looks at defining and collecting the correct measurements and data for specific purposes and deducing networks from data. The second examines mathematical properties of algorithms in networks, for example, the famous PageRank that Google invented to rank web pages. The third looks at efficient algorithms for computing network characteristics when the complete network data is not available. She was born on January 27 1972, in Nizhny Novgorod (at that time, Gorky) in Russia. She lived in her home city until June 1999 when she moved to the Netherlands. She is married to Pranab Mandal and has two beautiful daughters Natalia (born in 1993) and Piyali (born in 2005).

11.30u Presentatie Erik Fledderus (Technische Universiteit Eindhoven)

**Title:** Structuring a digital world

**Abstract:** My study Applied Mathematics in Twente ran from 1988 until 1993, followed by a PhD at the same department. I left Twente, and the University, on November 30, 1997. In many ways, it has been a defining period in my life. The interest in mathematics moved from recreational to professional, and broadened. I met people that I still consider as friends, and some of them have been colleagues at KPN Research, TNO and SURF. A trip to memory lane – but also a sense of homecoming; that’s what alumni-meetings are for me. We have joint experiences, where I would mention the Mathematisch Café and the afternoon-tea with Stefan van Gils.

I will not dwell too long through memory lane, but will tell something about the field that I entered after my PhD: mobile communication, ICT, and digital transformation of science & society. My fascination for self-organization, where non-local ordering emerges from local principles, will be present in a number of examples. It started during my PhD, in mathematical physics, where I met a kind of clarity that is not always present in real-life. Nonetheless, the time in Twente has shaped and sharpened my way of looking at things.

**Biography: **After a masters and a PhD in Applied Mathematics (1988-1997), Erik Fledderus started working at KPN Research in December 1997, in the field of mobile communications. In 2003, KPN decided to spin-out its research to TNO, and Erik continued working for TNO ICT. In the same year, he started as part-time professor at Eindhoven University of Technology, in the field of wireless communication. Erik had various positions at TNO, ranging from program manager, managing director and principal scientist. In 2015 he left TNO for SURF, taking on the position of managing director and chairman of the board of SURF.

12.00u Presentatie Jacqueline Scherpen (Rijksuniversiteit Groningen)

**Title: **Handling complexity of control systems with Applied Mathematics as basis

**Abstract:** Since my Master and PhD degree in Applied Mathematics, I continued my career at universities. In this presentation I will provide some background and ideas about my time in Twente, where the basis for my current teaching and research interest was layed. Then I will continue with the a brief overview of my research of complex control systems.

**Biography:** Jacquelien Scherpen studied Applied Mathematics at the University of Twente, where she also gained her PhD in 1994 with a thesis entitled Balancing for nonlinear systems. She then went on to work at the TU Delft, after which she became Professor of Discrete Technology and Production Automation at the University of Groningen in 2006. Jacquelien Scherpen has been Director of the Engineering and Technology Institute Groningen since January 2013. She has held visiting positions at Universite de Compiegne, France, SUPELEC, Gif-sur-Yvette, France, Old Dominion University, VA, USA, University of Tokyo, Japan and Kyoto University, Japan. Her research area covers order reduction methods for nonlinear control systems in order to make control design and implementation feasible for complex nonlinear systems. Furthermore, she studies the design of distributed and often nonlinear controllers for complex applications. Examples of such systems can be found in industry, robotics, micro systems, semi-conductors, energy systems, smart grids and space applications

12.30u Lunch

14.00u Pitches door studenten waarin zij hun onderzoek uitleggen

14.30u Presentatie Erjen Lefeber (Technische Universiteit Eindhoven)

**Title: **How to control traffic lights or factories

**Abstract: **What do intersections, a chip factory, a brewery or chemical plants have in common? They can be viewed as a network of servers that serve different types of jobs in large amounts, and when switching between types a setup time is involved. Intersections controlled by traffic lights serve cars from different directions where some time elapses between turning the lights for one direction to red, and turning the lights for an other direction to green. Similarly, in factories serving different types of jobs, time elapses between switching from serving one job type to serving an other job type (due to setups, for example cleaning of pipes). As a result it is beneficial to serve batches of jobs of one type before switching to serving an other type. But how many jobs should one serve before switching, and when switching: which job type should be served next?

15.00u Koffiepauze

15.30u Presentatie Maartje van de Vrugt (Universiteit Twente / Leiden University Medical Center)

**Title: **Catching patients and hospital flows in mathematical formulas

**Abstract: **During my daily work at the hospital, my ultimate goals are improving the quality of the delivered care, satisfaction of healthcare practitioners, and patient friendliness. My current job is very similar to my PhD-research; it is a combination between mathematical theory and practical healthcare projects. In this talk I will provide some examples of the projects I work on, and have worked on.

**Biography: **Maartje van de Vrugt is a part-time postdoctoral reseacher with CHOIR, at the University of Twente, and part-time employed by the Leiden University Medical Center (LUMC) as an advisor on patiënt logistics. Maartje has defended her PhD-thesis entitled “Efficient healthcare logistics with a human touch” on July 1^{st} 2016, at the Stochastic Operations Research group of the University of Twente. Her PhD-research was conducted in close collaboration with the Jeroen Bosch hospital. At the LUMC Maartje works on various logistical projects, among which determining the relation between yearly production plans and the required capacity. Her research focuses on multi-appointment scheduling and operating room scheduling.

16.00u Eindpresentatie Anatoliy Babic (SciSports)

**Title: ** Applied mathematics in the world of football

**Abstract: **The company SciSports is a University of Twente spin-off founded by Giels Brouwer and Anatoliy Babic. They started 5 years ago with the dream that football players can be scouted using objective performance data and mathematical algorithms. Currently, their services are offered to more than 20 football clubs from more than 5 different countries. Anatoliy will tell about his experience of studying Applied Mathematics at the University of Twente, and elaborate on mathematical models and future plans of SciSports.

**Biography:** Anatoliy Babic, originally born in the Kiev (Ukraine), moved to the Netherlands at the age of 6. From a young age, he has been fascinated with applied sciences, mainly mathematics. During his Bachelor, he founded the company SciSports with his housemate Giels Brouwer. After finishing his Bachelor's, he worked 1 year as a screen trader for the financial company Optiver. After this brief encounter with working life, Anatoliy decided to pursue his Master, again Applied Mathematics at the University of Twente. Last year he graduated, Cum Laude, with his research that he is currently implementing at SciSports.

16.30u Slotwoord dagvoorzitter

Gevolgd door een gezellig Italiaans buffet georganiseerd door WSG Abacus

## Fotoalbum

Bekijk de foto's van deze gezellige en interessante dag.