1.           (2008, november 11). “De school gaat over!” Utrecht, Lezing voor de Surf Onderwijsdagen

2.           (2008, july 24). Introduction to Web-based Communities. Amsterdam, Opening Speech IADIS International Conference Web Based Communities 2008

3.           (2008, june 16). Learning as Societal Awareness. Singapore, Ministry of Education Singapore, introduction to the 3rd round of National Projects

4.           (2008, december 11). Learning in Web-based Communities. Australian Centre for Educational Studies, Macquarie University, Sydney, New South Wales - Australia, Invited Lecture voor the Millennium Innovations Chair of ICT and Education

5.           (2008, july 26). Mirrored Images of the Mind. Amsterdam, Opening Speech IADIS International Conference Visual Communication 2008

6.           (2008, december 02). Mobile and Virtual Presence in the Learning Community. Melbourne - Australia, Keynote presentation vor de ASCILITE-2008 Conference

7.           (2008, april 09). Networked Society Community-wise. Algarve - Portugal, IADIS International Conference e-Society 2008

8.           (2008, july 29). Student Exchange as a Learning Attitude. Hagen - Germany, Lecture for the US-EU Atlantis Project

9.           (2008, october 07). The Real in Virtual- and Mobile Presence. Finland Academy of Sciences, State of the Art Introduction at the opening of the Interim Project Architecture

10.        (2008, march 06). Web Communities in education. Sittard, Lecture for the Fontys Teacher College, Sittard. Expertise chain "Educational functions of ICT"

11.        (2007, december 06). Conceptual layers in learning: From connections to relationships. Jung-li City, Taiwan, Graduate School of Network Learning Technology, National Central University

12.        (2007, september 12). Learning amongst the young Generation in the new University. Hamburg, Keynote for the Europäische Jahrestagung Gesellschaft fur Medien in der Wissenschaft

13.        (2007, october 03). Learning as Design; Keynote. Cape Town, South Africa, DEFSA Conference

14.        (2007, december 10). Learning for the evolution of human life. Taipei City, Taiwan, School of Information Education, National Taiwan Normal University.

15.        (2007, december 04). Mobile and virtual learning communities. Kaohsiung, Taiwan, The Future University National Sun Yatsen University

16.        (2007, october 19). Next Learning: Youth Culture Designing the Future. Waseda University, Tokyo, Lecture for the 125th anniversary of Waseda University

17.        (2006, november 15). Consistence and orientation in learning support. Den Bosch, Chair and lecture for the inauguration by Frank de Jong, STOAS

18.        (2006, september 28). Tools and methods for ICT in teacher training. Utrecht, Lecture for the iCT HPO Lectors

19.        (2006, december 05). ICT and societal consciousness. Groningen, Guest lecture for ECNO

20.        (2006, september 15). Presence in the virtual learning society. Anadolu - Turkije, 2nd international open and distance learning symposium

21.        (2006, december 14). Real concepts in the virtual experience. Bangkok - Thailand, International Conference on "e-learning: learning theories vs technologies?"

22.        (2006, november 01). WWW-based communities. Goteborg - Sweden, EU 7th FP consortium

23.        (2006, march 03). ICT as incentive for didactic innovation. Guest lecture for “Docenten en Innovatief Beroepsonderwijs”

24.        (2006, february 16). Should Teachers be trained as they are supposed to teach? , Presentation in “Role of a Teacher: Now and Then” Panel chaired by Madhumita Bhattacharya and Piet Kommers. ICALT 2006

25.        (2006, january 23). Web-based communities: improving tools and methods. Puerto Vallarta, Mexico, The fifth IASTED International Conference on web-based communities

26.        (2006, august 30). Stereopsis and dynamic exploration for anatomical learning. Utrecht, medical faculty UMC, “First VR Symposium.”

27.        (2005, july 22). WWW-based Communities: Manifestations of Self-Organization and Existential Learning. Las Vegas, USA, Introduction to the 1st International Conference on Online Communities and Social Computing, subconference of the 11th International Conference on Human Computer Interaction

28.        (2005, july 23). Conceptual Navigation for Virtual Environments in Medical Training. Las Vegas, USA, 11th International Conference on Human Computer Interaction

29.        (2005, october 27). “Mobile devices in education”;  Inaugural speech for Fontys, Eindhoven, the Neterhlands

30.        (2005, june 20). Media for Cultural Heritage in Education. Qawra, Malta, Lecture for the Malta Summer School  'International PhD Summer School on Educational Technology in a Cultural Context'

31.        (2005, june 27). Opening speech as 1st co-chair of the Program Committee of the EdMedia-20 Conference. Montreal, Canada, EdMedia-20 Conference

32.        (2005, june 27). Refinding Oneself in the Web Society. Qawra, Malta, Opening Speech at the E-Society Conference

33.        (2005, march 17). Virtuality for Professional Training. Tokyo, JSiSE International Seminar; Human Development for Knowledge-Based Society

34.        (2004, october 29).  Design Rational and Experimentation in VR for Medical Interventions Paper presentation for the Human Factors and Ergonomics Society Europe Chapter An­nual Meeting, Delft

35.        (2004, october,23). Conceptual Representations for  Virtual Environments Keynote for The 1st international conference on ICT oriented teachers' professional development will be held in Beijing, China

36.        (2004, june 30). ICT: The Nature and Culture of WWW Presence Lecture for the Centre for Research and Development in Higher Education. Hokkaido Univer­sity. Sapporo, Japan

37.        (2004, june 02). Vascular Specialists Training, The Practice and The Future. The Hague, The Netherlands, Paper on the International congress on Medical and Care Compunetics

38.        (2004, February 10).Living in Virtual Worlds”. Lecture for the UNESCO Workshop. Bucharest

39.        (2004, january 22). Conceptual Navigation in VR Documentary Spaces. Tilburg, Nederland, Paper for the Document Design Conference 2004 in Tilburg

40.         (2004, may 23). Using Concept Maps to Improve the Usage of Bibliometric Data. Leiden, Nederland, Paper for the Eighth International S&T Indicators Conference

41.        (2004, march 24). Web-Based Communities: Ideology or Pragmatics? Lisbon, Portugal, Opening Speech for the Conference "Web-based Communities"

42.        (2003, april 02). Adaptive scenarios for student-oriented learning. Nagaoka, Japan, Invited workshop for staff members of Nagaoka University of Technology

43.        (2003, april 04). VR for pulling the Understanding before Learning Guest Lecture in the AI and Knowledge Computing Lab, University of Electro-Communications,. Tokyo, Japan

44.        (2003, march 31). Problem-based Learning for Engineering Design and the Reform of Engineering Education in Europe; in particular the University of Twente in the Nether­lands” Guest Speaker Department of Adaptive Ma­chine Systems, Graduate School of Engineering, Osaka University, Japan

45.        (2003, june 03). Conceptual representations for learning. Lisbon, Portugal, Invited speach for the iadis international conference e-society 2003

46.        (2003, april 23). Distributed interactive medical exploratorium for 3rd medical images. Paris, France, Paper presentation on the 3d modelling 2003 conference

47.        (2003, december 07). Learning technology: autonomous and mediated www-based communities and the use of virtual reality. Mauritius, Key-note speech for ICOOL 2003

48.        (2003, june 05). Learning through conceptual imigination in virtual environments. Cyprus university, Nicosia, Keynote on the 2003 CBLIS conference

49.        (2003, september 01). Learning yourself in a mediated world. University of Joensuu, Finland, Keynote for the second international conference on educational technology in cultural context

50.        (2003, october 10). Media and the nature of learning. Helsinki, Invited lecture for the annual symposium of the Finnisch mathematics and science education research association

51.        (2003, march 31). Problem-based learning for engineering design and the reform of engineering education in europe; in particular the University of Twente in The Netherlands. Osaka University, Japan, Guest speaker department of adaptive machine systems, graduate school of engineering

52.        (2003, january 21). Trends in de ontwikkeling van en onderzoek aan electronische leeromgevingen. Universiteit Twente, Enschede, Slotlezing bij de VOR werkgroepdag

53.        (2003, september 16). Universities: facilitators of new www-based learning communities. Roznov pod Radhostem, Czech Republic, Conference information and communication technology in education

54.        (2003, september 11). Virtual environments and the shift in learning paradigms. Kosice, Slovak Republic, Invited lecture for the 2nd international conference on emerging telecommunications technologies and applications and the 4th conference on virtual university

55.        (2003, september 02). Visual representations for conceptual awareness in learning cultures. University of Joensuu, Finland, Keynote for the first international conference on educational technology in cultural context

56.        (2003, april 04). VR for pulling the understanding before learning. Tokyo, Japan, Guest lecture in the AI and knowledge computing lab, university of electro-communications

57.        (2003, november 10). Is universal usability universal only to us? Vancouver BC Canada, Paper for the ACM conference on universal usability 2003

58.        (2002, july 2). The Future of Technology and the Challenges faced by those who need to accept Technology. Invited lecture for The International Cultural Research Network Con­gress; Brasilia, July 2, 2002: Exploring Cultural Per­spectives

59.        (2002, september 2). Visual Representations for Conceptual Awareness in Learning Cultures;” Keynote for the First International Conference on Educational Technology in Cultural Context, University of Joensuu, Finland

60.        (2002, september 05). Conceptual Design of Scenarios for Educational TV-programs. Hilversum, the Netherlands, Media Academy.

61.        (2002, september 26). Imagination and the Expression of Learning Experience. Villach, Austria, The International workshop "Interactive Computer-Aided Learning

62.        (2002, august 11). In-depth Learning through Conceptual Navigation in Virtual and Hyper Space. Davos, Switzerland, E-Technologies in Engineering Education: Learning Outcomes Providing Future Possibilities

63.        (2002, april 26). Invited Speech. Moscow, UNESCO expert panel "ICTs in Technical and Vocational Education and Training"

64.        (2002, september 09). Media for Transforming the Learning Culture. Kazan, Russia, IEEE International Conference on Advanced Learning Technology

65.        (2002, may 15). The Establishment of a WWW-based University and Learning Communities. Izmir, Turkey, Presentation for the Dokuz Eylul University faculties of Education and Information Sciences

66.        (2001, february 01). Invited Guest Speaker Workshop on Manufacturing Creative E-learning Environments. European Consor­tium of Innovative Universities. Bayesian Reasoning for Inductive Query Reduction. Joen­suu. Finland

67.        (2001, may 23). Opening Speaker for the Conference “Telecommuni­cations for Education and Training” Prague, Czech Republic

68.        (2001, june 04). Are schools learning organizations? Izmir, Turkey, Paper presented at the Educational Conference

69.        (2001, june 13). Guest Speaker for the Celebration Conference of MESI (Moscow Economical and Statistical Institute): “Virtuality for Organizational Change”

70.        (2001, august 06). Sharing learning experiences through correspondence on the WWW: Collaborative context-mediated experiential learning through asynchronous learning networks. Madison, WI, Paper presented at the International Conference on Advanced Learning Technologies (ICALT-2001)

71.        (2001, august 07). Genres, user attitude and new prospects for learning through video on the WWW: The integration of TV and the internet. Madison, WI, Paper presented at the International Conference on Advanced Learning Technologies (ICALT-2001)

72.        (2001, august 08). Genres, User Attitude and New Prospects for Learn­ing through Video on the WWW; Panel Contribution for the ICALT-2001 Conference, Wisconsin, USA

73.        (2001, october 11). Invited Speaker for the Portugese Open University: Universidade Aberta. Learning in Concept Space: Beyond the Multimedia and 3D Metaphors, Lisbon

74.        (2000, march 14). Metaphoric Stages in Multimedia Design. Opening Lecture for the Tempus JEP 12418 Project "Creation of a Master Degree Program in Multimedia and Learning Systems". Tallin, Estonia

75.        (2000, november 08). Knowledge as Conceptual Awareness" Presentation for the Univ. of Twente Knowledge Group, Univ. of Twente. Invited Lecture

76.        (2000, december 04). Imagination through virtuality for in-depth learning. Keynote speech for the International Workshop on Advanced Learning Technologies, IWALT 2000: Palmerston North, New Zealand

77.        (2000, july 04). Playing for cognitive growth: Learning the unknown. Keynote speech,International Simulation and Gaming Association, ISAGA 2000, Tartu, Estonia

78.        (2000, march 30). Telematics and the restructuring of eastern european universities. Invited lecture for the National Conference on New Media in Education: Uzbekistan, Tashkent Davlat Technical University

79.        (2000, march 22). Autonomous processes in the learning digital communities. Lviv, Ukraine, Presentation to tthe Tempus Tacis Project UM_CP-20527-1999

80.        (2000, july 17). Cognitive tools for existential learning. Cesme, Turkey, Workshop for the "Keep in Touch Project"

81.        (2000, march 02). Evolution in Intuitive Learning Tools. Umea University, Sweden, Presentation in the Computer Science Department Umea University

82.        (2000, february 08). Knowledge as conceptual awareness. Presentation to the Twente University Knowledge Group

83.        (2000, july 06). Media and learning of the unknown. Zutphen, Invited lecture for the Didactic Faculty Hogeschool Zutphen

84.        (2000, march 13). Metaphoric stages in multimedia design. Tallin, Estonia, Opening lecture for the Tempus JEP 12418 Project "Creation of Master Degree Programme in Multimedia and Learning Systems"

85.        (2000, october 17). Radio-Broadcasted interview on "Memory Style and Learning" and "E-Commerce for the Networking So­ciety" for the VPRO program "Café de Wetenschap" 11-12 AM

86.        (2000, february 08). Telematics for the evolution of educational practices. l`Aquila, Italy, Presentation at SSGRR 2000

87.        (2000, march 12). Position Paper for TiCSE 2000. Helsinki, The 5th Annual Conference on Innovation and Technology in Computer Science Education; Conceptual Orientation for Learning: Looking Through Mental Space

88.        (1999, march 23). Autonomous Processes in the Learning Digital Communities. Contributive Lecture for the Tempus Tacis Project UM_CP-20527-1999. Lviv, Ukraine

89.        (1999, march 28). Invited speaker for the European TACIS Project TN RUS 9310 "Open and Distance Learning System for Air Traffic Controller Flexible Refresher Training (ATC FRT). “Multi-Level Queries for Concurrently Indexing of a Visual- and Speech Attribute Database.” Moscow

90.        (1998, december 16). “Connectivity: Blessing or Plague?” Leeuwarden, Keynote speech for the opening of the new Communication Studies Department. Leeuwarden.

91.        (1998, march 26). Conceptual Support with Virtual Reality in Web-based Learning. Maastricht, Bite Conference

92.        (1998, august 30). Multimedia for the Evolution of Learning Paradigms. Vienna, Presentation at IFIP98 Conference

93.        (1998, march 05). The VMF Project. Cyprus, Presentation at he EuroMedNet '98.

94.        (1998, september 17). Virtuele Leeromgevingen: Naar een nieuwe Realiteit voor Onderwijs en Opleiding. Amsterdam, Inleiding voor de IMTO Conferentie

95.        (1998, may, 23). Invited lecture: “Metadata and Ontologies.” Sympo­sium Osaka University; May 1998. Mizoguchi Lab

96.        (1998, february 26). Virtuele Omgevingen voor Conceptuele Orientatie tijdens Leertaken. Enschede, Lezing en Voorzitterschap van de SIG CHI Conferentie.

97.        (1998, may 26). Een model aangaande leren: een analogon. Utrecht, Paper presentatie voor de NOSMO Onderzoeksgroep.

98.        (1996, may 02). Collaborative concept mapping. Amman, Jordan, guest lecturer at Jordan University

99.         (1997, june, 22). EdMedia´97. Invited Speaker: “Multiculturality and the new Existentialism” Calgary

100.     (1996, june 02). Concept mapping as a generic activity at several stages in the learning process. Cuenca, Spain, guest lecturer at Universidad Internacional Menendez y Pelayo

101.     (1996, october 02). Concept mapping methods for metacognitive awareness. Shanghai, China, guest lecturer at East China Normal University (ECNU)

102.     (1996, october 01). Hypermedia and its navigation complexity. Shanghai, China, guest lecturer at East China Normal University (ECNU)

103.     (1996, november 19). ICT: Multimedia, hypermedia en telematica: Implementatievoorwaarden. Utrecht, The Netherlands, voordracht voor BVE-Digitaal

104.     (1995, august 16). Cognitive learning tools: Entropic and synergetic mechanisms in the student mind. Kusadasi, Turkey, opening presentation for the 2nd MedCampus CogTech Conference