Organization services
  1. Program co-chair of the Second International Workshop on Collaborative Social Network (CollaborateSN'10) in conjunction with IEEE CollaborateCom'10,Chicago, Illinois, USA, October 9-12, 2010.

  2. Program chair for the 15th ACM Symposium on Access Control Models and Technologies (SACMAT) (SACMAT 2010) Pittsburg, USA, 9-11, 2010.

  3. Workshop co-chair for the 6th International Conference on Collaborative Computing: Networking, Applications and Worksharing (CollaborateCom'10) Chicago, Illinois, USA, October 9-12, 2010.

  4. Program co-chair of the First International Workshop on Collaborative Social Network (CollaborateSN'09) in conjunction with IEEE CollaborateCom'09,Crystal City,Washington D.C., USA, November 11-14, 2009.

  5. Program co-chair of the First International Workshop on Secure Service Computing (SSC'09) in conjunction with IEEE APSCC 2009, Singapore, December 7-11, 2009.

  6. Tutorial co-chair for the 5th International Conference on Collaborative Computing: Networking, Applications and Worksharing (CollaborateCom'09) Crystal City, Washington D.C., USA, November 11-14, 2009.

  7. General chair for the 14th ACM symposium on access control models and technologies (SACMAT) (SACMAT 09) Stresa, Italy, June 3-5, 2009.

  8. Tutorial co-chair for the 4th International Conference on Collaborative Computing: Networking, Applications and Worksharing (CollaborateCom'08) Orlando, FL, USA, November 13-16, 2008.

  9. Program co-chair for the first International Workshop on Secure Semantic Web (SSW'08) in conjunction with the 24th International Conference on Data Engineering (ICDE'08),Cancun, Mexico, April 7-12, 2008.

  10. In the organizing Committee of the ACM Symposium on Access Control Models and Technologies (SACMAT 2003), Como, Italy.

Editorial services
  1. Guest editor of special issue on Secure Semantic Web in Computer Standards & Interfaces

Program Committees
  1. First ACM Conference on Data and Application Security and Privacy (CODASPY'10), San Antonio, TX, USA.

  2. 3rd IEEE International Symposium on Trust, Security and Privacy for Emerging Applications (TSP'10), Bradford, UK, 2010.

  3. 11th IEEE International Symposium on Policies for Distributed Systems and Networks (Policy 2010), Fairfax, Virginia, USA, 2010.

  4. International DEXA Workshop on Web Semantics ( WebS 2010), Bilbao, Spain, 2010.

  5. 5th International Conference on Availability, Reliability and Security (AReS 2010), Krakow, Poland, 2010.

  6. IEEE International Conference on E-business (ICE-B), Athen, Greece, 2010.

  7. IEEE International Conference on E-business ( ICE-B), Milan, Italy, 2009.

  8. IEEE Asia-Pacific Services Computing Conference (APSCC 09), Singapore, 2009.

  9. 7th International Joint Conference on Service Oriented Computing (ICSOC-ServiceWave), Stockholm, Sweden, 2009.

  10. 4th International Conference on Availability, Reliability and Security (AReS 2009), Fukuoka, Japan, 2009.

  11. International DEXA Workshop on Web Semantics ( WebS 2009), Linz, Austria, 2009.

  12. 35th International Conference on Very Large Database(VLDB 2009 ), Lyon, France, 2009.

  13. 18th International World Wide Web conference(WWW 2009 ),Madrid, Spain, 2009.

  14. The 33rd Annual IEEE International Computer Software and Applications Conference (COMPSAC 2009), Seattle,Washington, 2009

  15. 13th ACM symposium on access control models and technologies (SACMAT 2008 ), Estes Park, Colorado, USA

  16. The 24th International Conference on Data Engineering (ICDE'08),Cancun, Mexico, 2008.

  17. International DEXA Workshop on Web Semantics (WebS 2008), Turin, Italy, 2008.

  18. The Third International Conference on Internet and Web Applications and Services (ICIW 2008) , Athens, Greece, 2008.

  19. Third International VLDB Workshop on Services Engineering (SEIW 2008 ), Auckland, New Zealand,2008.

  20. Third International Workshop on Dependability Aspects on Data WArehousing and Mining applications(DAWAM 2008 ), Barcelona, Spain 2008.

  21. The Second ACM SIGKDD International Workshop on Privacy, Security, and Trust in KDD (PinKDD'08), Las Vegas, NV, 2008.

  22. The 6th International Workshop on Privacy Aspects of Data Mining (PADM 2007), Nebraska, United States, 2007.

  23. The First ACM SIGKDD International Workshop on Privacy, Security, and Trust in KDD (PinKDD'07), San Jose, CA, August 2007.

  24. IEEE Middleware for Web Services (MSW07) Workshop, Annapolis, Maryland, USA, 2007.

  25. Second International ICDE Workshop on Services Engineering (SEIW 2007 ), Istanbul, Turkey, 2007.

  26. Second International Workshop Dependability Aspects on Data WArehousing and Mining applications (DAWAM 2007).

  27. International DEXA Workshop on Web Semantics (WebS 2007), Regensburg, 2007.

  28. IEEE International Conference on E-business (ICE-B), Barcelona, Spain, 2007

  29. WEBSA 2006: Web Services-based Systems and Applications at the International Conference on Internet and Web Services (ICIW06), Guadeloupe, French Caribbean, 2006.

  30. International DEXA Workshop on Web Semantics ( WebS 2006), Munich, 2006.

  31. IEEE Middleware for Web Services (MSW06) Workshop, Hong Kong, 2006. 2007.

  32. IEEE International Conference on E-business (ICE-B), Setubal, Portugal, 2006.

  33. IEEE Conference on Privacy, Security and Trust (PST 2006), Ontario, Canada.

  34. International Conference on Wireless and Mobile Communications (ICWMC06), Bucarest, Romania.

  35. IADIS Database Systems 2006 (DS2006 )

  36. International DEXA Workshop on Web Semantics ( WebS), Copenhagen, 2005.

  37. IEEE International Conference on e-Technology, e-Commerce and e-Service (EEE05), Hong Kong, Japan, 2005

  38. IEEE International Conference on Cooperative Information Systems (CoopIS 2005), Agia Napa, Cypro, 2005.

  39. IEEE International Conference on Services Computing (SCC 2005 ), Orlando, USA, 2005.

  40. IEEE Middleware for Web Services (MSW05) Workshop, Enschede, Netherlands, 2005.

  41. IEEE International Workshop on Business Services Networks (BSN 2005), Hong Kong, Japan, 2005.

  42. International Conference on Cooperative Information Systems (CoopIS 2004), Larnaca, Cypro, 2004.

  43. 9th ACM Symposium on Access Control Models and Technologies (SACMAT 2004), Yorktown Heights, USA, 2004.