Invited Presentation: "Requirements Management with Use Cases", Workshop of the German Virtual Competence Centre for Software Engineering, Fraunhofer FIT, Sankt Augustin, Aug. 21, 2001.

Software demonstration: "Bridging the Gap Between Past and Future in RE: A Scenario-Based Approach", Computer Science day at the Technical University of Aachen, Dec. 4, 1999.

Invited talk: "Requirements Engineering with Interrelated Conceptual Models and Real World Scenes", Séminaire d'Informatique Institut d'Informatique, University of Namur, FUNDP, Belgium, Oct. 10, 1999.

Software demonstration: "Bridging the Gap Between Past and Future in RE: A Scenario-Based Approach", 11th Conf. on Advanced Information Systems Eng., (CAISE '99), Heidelberg, Germany, Jun. 15, 1999.

Paper presentation and software demonstration: "Bridging the Gap Between Past and Future in RE: A Scenario-Based Approach", 4th IEEE Int'l. Symposium on Requirements Eng. (RE'99), University of Limerick, Ireland, Jun. 10, 1999.

Talk: "Requirements Engineering with Interrelated Conceptual Models and Real World Scenes", Doctoral Symposium at the 4th IEEE Int'l. Symposium on Requirements Eng. (RE'99), University of Limerick, Ireland, Jun. 7, 1999.

Paper presentation: "Improving Reviews by Extended Traceability. Minitrack on Scenario-Based System Development", Emerging Technologies Track, Thirty-Second Hawaii Int'l Conf. on System Sciences (HICSS-32), Jan. 1999.

Tutorial "Requirements Elicitation from Real World Scenes", Tutorial 1: The CREWS Approach to Requirements Engineering: Scenarios, Scenes and Use Cases, The 5th Int'l. Conf. on Object Oriented Information Systems (OOIS'98), Paris, France, Sep. 1998.

Paper presentation: "Interrelating Conceptual Models with Real World Scenes", 4th Int'l. Workshop on Requirements Eng.: Foundation of Software Quality (REFSQ '98), Pisa, Italy, Jun. 8, 1998.

Software demonstration: "Interrelating Conceptual Models with Real World Scenes", RESG Scenario Day, one-day symposium of the British Computer Society (BCS): Requirements Engineering Specialist Group (RESG), How to Use Scenarios and Use Cases in the Systems Development Process, London, May 14, 1998.

Talk: "Interrelating Conceptual Models with Real World Scenes", Int'l. Seminar on Scenario Management, Seminar 9806, Schloss Dagstuhl, Wadern, Germany, Feb. 9-13, 1998.

Paper presentation: "Modelling Contextual Information about Scenarios", 3rd Int'l. Workshop on Requirements Eng.: Foundation of Software Quality (REFSQ '97), Barcelona, Spain, Jun. 17, 1997.

Talk: "Scenario-based Requirements Engineering", Annual Meeting of Requirements Engineering Group of German Computer Society (GI-FG 2.1.6), Aachen, Nov. 29, 1996.

Paper presentation: "HYDRA: A hypertext model for structuring informal requirements representations", 2nd Int'l. Workshop on Requirements Eng.: Foundation of Software Quality (REFSQ '95), Jyväskylä, Finland, Jun. 13, 1995.

Software demonstration: "Requirements Pre-Traceability with NATURE/PRO-ART", Trade show, "Future Technology from Aachen", Technology Centre Aachen, Oct. 1994.

Invited software demonstration: "Requirements Pre-Traceability with NATURE/PRO-ART", Naval Postgraduate School in Monterey, CA, USA, Sept. 1994.