I have been on the program committee of many national and international
conferences, organized and chaired special sessions etc.
I was one of the organizers of the 11th International Symposium on Mathematical
Programming, Bonn 1982.
In the past few years I have organized the following conferences: the international conference ``Operations Research 1994'' in August/September 1994, jointly with three colleagues from the Technical University Berlin; the Oberwolfach Conference on ``Large-Scale Discrete Systems'' in February/March 1995, jointly with Thomas Beth (Karlsruhe); in March 1995 a joint workshop of the DMV, DPG, GDCh and GI ``New ways for scientific information and communication''.
I was the President of the Organizing Committee for the International Congress of Mathematicians 1998 (ICM'98), which took place in Berlin in August 1998. As a member of the IMU Committee on Electronic Information and Communication (CEIC) I organized two meetings of this committee in Berlin ( May 20-22, 2003 and February 24-26, 2006). In my function as a member of the IMU Executive Committee (1999-2006) I supported in a different manner the organization of the annual EC meetings and of the ICM'2002 in Beijing (China) and the ICM'2006 in Madrid (Spain). In my function as IMU Secretary (2007-2014) I was involved in the preparation and organization of the ICM'2010 in Hyderabad (India) and the ICM'2014 (August 13-21, 2014) in Seoul (Korea), and the IMU General Assembly meeting in Gyeongju (August 11-12, 2014).