Additional information was provided by Eugene J.H. Kerckhoffs, August 2016: "On the way to a Federation of (regional) European Simulation Societies - The prehistory of EUROSIM (1979 – 1989)", see full paper as PDF (1,5 MB).

In Memoriam Prof.dr.ir. Len Dekker (1932-2006)

In October 2006 the very sad news arrived that Prof. Len Dekker has passed away. Len Dekker is the founder of the Dutch-Benelux Simulation Society (DBSS) and has served as the chairman of DBSS for a long time, and he is a co-founder and a former president of EUROSIM (1998-2001).

Prof. Len Dekker was full-professor at the Faculty of Applied Mathematics and the Faculty of Applied Physics at the Delft University of Technology. All through his life he had devoted his research to advancing the computing systems for system simulation. His interest in computer simulation began at the end of 1960s, by that time computer was still in its infancy, the most common applications were doing some calculations and counting in administration. Computers by then had very limited memory (a few Kbytes) and were very slow compare to today’s standard. Prof. Len Dekker and his research group at Delft University were fascinated by the challenge of increasing the processing speed of the computing systems. In the earlier 1970s Len Dekker has designed and built a hybrid (analog-digital) computer for simulation of dynamic systems modelled by a set of differential equations. The analog system comprises a number of ‘integrators’ realized with analog amplifiers. This hybrid computer system has been installed at the computing centre in the early 70s and has served as a powerful simulation tool.

The hybrid computer system is in fact one of the earliest parallel computers. ‘Parallel processing’ has been the research focus of Len Dekker for more than three decades. After the completion of the hybrid computer system, he and his research group started to design and to implement the Delft Parallel Processor (DPP). The first DPP with 8 processors become operational in the mid-1970, unlike the hybrid system the DPP comprises only digital processing units. It was one of the first parallel computers by that time. Len Dekker was a research pioneer in parallel processing. In the 80s and 90s computer technology has made a tremendous progress both in processor speed and memory storage that commercial computer manufacturers flood the market with parallel (super)computers. Len Dekker has turned his focus to parallel algorithms and parallelization of large scale systems simulations. Len Dekker retired from Delft University of Technology in 1997.

Prof. Len Dekker has also devoted much of his time to the DBSS and has served for a long time as the chairman. He is also one of driving forces in setting up the Federation of European Simulation Societies (EUROSIM) being well recognizable president  in the period 1998-2001 which finished by EUROSIM 2001 Congress in Delft.  He was the DBSS representative in EUROSIM board for many years. Furthermore he has set up the journal Simulation Practice and Theory and served as the first editor-in-chief of the journal for many years. His efforts and devotion in these different areas have helped many people in the fields of simulation. We are indebted to his many contributions to the scientific community.

Arnold Heemink, Borut Zupančič