• Since 1990 member of GI (German Society of Informatics)
  since 2002 in new Special Interest Group Mensch&Computer (HCI)
• Since 2004 ACM SigCHI member. 2016 accepted nomination as ACM Senior member  
• Since 1995 member of FIfF (Forum InformatikerInnen für Frieden und gesellschaftliche Verantwortung), the German sibling of CPSR.   (1997-2002 contact person for the regional working group of FIfF in Bremen)
• End 1999 - Nov. 2005 member of the board of chairs of FIfF-Vorstand (Vorstand)
• Since Feb 2007 member of FIfF scientific advisary board
  
• 2002 invited into the working group 'Responsibility' (Verantwortung) to update and rewrite the German Society of Informatics (GI e.V.) Ethical Guidelines (ethische Leitlinien) 
• October 2003: founding member of the informatics and ethics SIG of GI ("Informatik und Ethik")
• Spring 2008, founding member of new working group  "Be-Greifbare Interaktion in Gemischten Wirklichkeiten" in the MCI  SIG of the German society of Informatics GI (tangible interfaces in mixed realities) 
• associate chair for German working group  Be-Greifbare Interaktion in Gemischten Wirklichkeiten  (graspable interaction in mixed realities) 2008-2010. Chair from 2015-current
   
  
• Co-editor of www.tangint.org  (wiki on Tangibles) with Brygg Ullmer & Albrecht Schmidt (defunct since 2006!)
• Initiator and list manager for TANGIBLE-INTERACTION@JISCMAIL.AC.UK  news and announcement email list 

     Reviewing Experience and Conference Involvement

• Reviewing for Funding Panels & Agencies
• Germany: (DFG), Finland: (Academy of Finland), UK: (EPSRC, Microsoft Research),
• Austria (Austrian Science Fund, FWF), Switzerland: (Schweizer Nationalfond),
• Belgium (local agencies), Netherlands , Sweden (Knowledge Foundation)
• Reviewing for Journals
  
• Reviewer for the Journal of Computer Supported Cooperative Work since 2006, 
• Journal of Computer-Mediated Communication, Interacting with Computers (since 2008), 
• Personal and Ubiquitous Computing journal special issue on Tangibles and Children, 
• ACM ToCHI since 2010
  
  
• Editorial roles
  
• forum editor for an article series on Tangible and Embodied Interaction for ACM interactions magazine (spring 2011 to end of 2014)
  
• on the Interacting with Computer’s Computer Science's Special Editorial Board since 2011
• on the editorial board of the International Journal of Human-Computer Studies since 2016.
  
• on the Editorial Advisory Board of the CSCW Journal since 2013
  
  
• Reviewing for conferences:
  
• IRIS'24 - 24th Information Systems Research Seminar in Scandinavia, 2001 (Long Papers)
• Coop 2004 - Intern. Conf. on the Design of Cooperative Systems 
• CSCW 2004, 2008 + 2010 - ACM Conf. on Computer Supported Cooperative Work 
• E-CSCW 2007 
• CHI  2005 (Work in Progress / Short Papers), 2006-2008 + 2010-2012 (Long Papers + CHI Notes)
• DIS (ACM Designing Interactive Systems) 2010
  
• UbiComp 2005, 2007, 2008-2010, 2013 - Ubiquitous Computing Conference, 
• OzCHI 2005 + 2006 (Australian Computer-Human Interaction Conference) (long + short papers)
• CHINZ 2006 – Design-oriented HCI, Christchurch NZ
• Tabletop 2007, 2009, ITS (ACM International Conference on Interactive Tabletops and Surfaces) 2010 and 2011, 2013
• TEI 2010 and 2011 Graduate Student Consortium
  
• ACM Designing Interactive Systems 2010 (DIS'10) , Create 2010
  
• 'Occasional' requested to review for Group 2005, ISMAR 2006, UIST 2009 + 2010, 2012, IDC 2010, IDC 2011, BritishHCI 2011, Interact 2011, NordiCHI 2012 etc
• .....
  
  
• Program Committee membership for Workshops: 
  'Tangible Interaction in Collaborative Environments' (TICE 2006) at the 15th International IEEE Workshops on Enabling Technologies (WETICE 2006) and TICE 2007,
  'Intelligent Environments' 2005, Special Session on 'How to Interact with Virtual Environments',
  MEIS 'Mobile and Embedded Interactive Systems' at GI-Jahrestagung 2006 and 2008 (German society of Informatics conference), 
  'Mixed Realities und Be-greifbare Interfaces für Bildungsprozesse' workshop at GI-Jahrestagung 2007, 
  second international 'Physicality' workshop, Lancaster 2007, 
  'User Interface Description Languages for Next Generation User Interfaces' workshop at CHI 2008,
  'Whole Body Interaction' workshop at BritishHCI 2008.
  Mensch&Computer 2010 and 2013 workshops on 'Be-greifbare Interaktionen'
  ... ? I did loose track of the workshops at some point...
  BCS HCI 2012 Workshop on Video Analysis Techniques for Human-Computer Interaction, Sept. 2012
  
  
• Technical Program Committee membership:
• Participatory Design Conference 2006 (PDC), PDC 2008, PDC 2010
• TEI 2008, TEI 2010, TEI 2011, TEI 2012, TEI 2013, TEI 2014, TEI 2019,
• IEEE Tabletop 2008,
• (re)Actor3  International Conference on Digital Live Art 2008, Create2010 in Edinburgh,
• E-CSCW 2009, E-CSCW 2011, 
  
• Mensch&Computer 2008 , 2013, 2014, 2015, 2016, 2017. (German HCI-conference)
• ACM MUM 2010 (Intern. Conference on Mobile and Ubiquitous Multimedia) and MobileHCI 2009, 
• The Re-Thinking Technology in Museums 2011 conference in Limerick,
• UbiComp 2011 in Beijing
• TPC member for the Creativity&Cognition Conference C&C 2015 in Glasgow, UK. amd C&C 2017.
• AC for DIS 2016 on the Experience track, Brisbane, Australia, DIS 2017 on the Experience Subcommitee.
• TPC member for UbiComp 2016 in Heidelberg
• RISE IMET 2020 (International Conference on Emerging Technologies and the Digital Transformation of Museums and Heritage Sites

Chairing roles

• I was workshop chair for Participatory Design Conference 2006
  
• Program Chair for TEI 2007 (Tangible and Embedded Interaction), Baton Rouge, Louisiana (ACM DL proceedings)
• member of TEI steering committee, chair of the TEI SC (since 2009)
• Associate Chair for CHI 2009 on the "Interaction Using Specific Capabilities or Modalities" sub-committee
• Theme Chair on the Processes theme for ACM DIS'12 (Designing Interactive Systems) in June 2012 in Newcastle, UK
• ACM CHI 2012 Interactivity Explorations Chair (with Danielle Wilde) (explorations is a new-subtrack within the overall Interactivty track)
• Poster co-chair both for ITS 2012(Interactive Tabletops and Surfaces) in Boston and ITS 2013 in St. Andrews
  
• Associate Chair for ACM CHI 2013 on the Design subcommittee, and for CHI 2014 on the Understanding People subcommittee
• Graduate Student Consortium co-chair at TEI'16 in Eindhoven, the Netherlands
• Subcommittee chair for DIS 2018 Experience subcommittee, in Hongkong
• Paper Chair for MUC 2020, the German HCI conference
  

Organization of workshops and other events

• Member of the organizing  committee for FIfF-Jahrestagung 2001  (annual FIfF conference) in Bremen (motto: "2001 - Odyssee in Cyberspace")
• Program committee for FIfF-Jahrestagung 2005 in Munich
  
  
• Co-organizer of workshop‚Physicality’ (Equator & British HCI), 6+7 February 2006, Lancaster, UK
• conference organizing committee (conference scheduler) for CHINZ 2006, Christchurch NZ, 
• Co-organizer of international Shareable Interfaces Workshop 2007, Open University, UK with Paul Marshall and Yvonne Rogers
• Co-organizer of workshop 'Theorie- und Praxiswerkstatt Be-greifbare Interaktion' at Mensch&Computer 2008, Lübeck, 
• Co-organizer of Shareable Interfaces for Learning workshop, Brigthon 12+12.9.2008, with Amanda Harris, Nicola Yuill, Paul Marshall and Yvonne Rogers in the context of the ShareIT project
• Co-organizer of CHI 2009 workshop on Whole-Body Interaction   
• Co-organizer of SICSA workshop on Whole-Body Interaction with Lynne Baillie (Caledonian University, Glasgow) and Steve Brewster (University of Glasgow) 5-6.11.2009
• Co-organizer of SICSA summerschool on Multimodal Systems for Digital Tourism with Aaron Quigley (University of St Andrews) and Jon Oberlander (University of Edinburgh) 27 June to 1 July 2011 in St. Andrews
• Organizer of SICSA MMI workshop on 'multimodal interaction and museum installation design', 30 May 2012 at the University of Strathclyde, with PhD student Loraine Clarke
• Cultural Heritage Communities:Technologies & Challenges. Workshopt at COMMUNITIES & TECHNOLOGIES 2015, 28 June (Limerick, Ireland). Organized with Luigina Ciolfi, Areti Damala, Monika Lechner, Laura Maye, and Daniela Petrelli.