Dr. Yuanshun Dai(3 books and over 40 Articles)

    Books

  1. Y.S. Dai, Y. Pan, R. Raje, eds., Advanced Parallel and Distributed Computing: Evaluations, Improvement and Practices, Nova Science Publishers, New York, USA, to be published in 2006.
  2. M. Xie, Y.S. Dai, K.L. Poh, Computing Systems Reliability: Models and Analysis, Kluwer Academic Publishers: New York, NY, U.S.A., April 2004. ISBN: 0-306-48496-X. [Cover]; [Online Order]
  3. T. Enokido, L. Yan, B. Xiao, D. Kim, Y.S. Dai, and L. Yang (Eds.), Embedded And Ubiquitous Computing, Lecture Notes in Computer Science (LNCS), Volume 3823, Springer-Verlag, Berlin, Heidelberg, New York, 2005. ISBN: 3-540-30803-2. [Cover]; [Online Order]

    Book Chapters

  4. G. Levitin, X.H. Hu, Y.S. Dai, “Particle Swarm Optimization in Reliability Engineering”, in Computational Intelligence in Reliability Engineering, Springer-Verlag, New York, USA, to be published in 2006.
  5. T. Marshall, Y.S. Dai, “Dependability Evaluation and Modelling”, in Advanced Parallel and Distributed Computing, Nova Science Publishers, New York, USA, 2006.
  6. X. Wang, J. Zhen, Y.S. Dai, “A web based city navigation application utilizing the mobile grid”, in Advanced Parallel and Distributed Computing, Nova Science Publishers, New York, USA, 2006.

    Edited Special Issue for Journal

  7. Y.S. Dai, Y. Zhang (Guest Editors), Special Issue on Reliability and Autonomic Management, Journal of Computer Science, ISSN: 1549-3636, Science Publications, New York, USA, plan to publish in 2006.

    Journal Articles Published and Accepted

  8. Y.S. Dai, M. Xie, K.L. Poh, “Modeling and analysis of correlated software failures of multiple types”, IEEE Transactions on Reliability, vol. 54, no. 1, pp. 100-106, March, 2005.
  9. Y.S. Dai, G. Levitin, “Reliability and Performance of Tree-structured Grid Services”, IEEE Transactions on Reliability, In Press, 2005.
  10. Y.S. Dai, M. Xie, X.L. Wang , “Heuristic Algorithm for Reliability Modeling and Analysis of Grid Systems”, submitted to: IEEE Transactions on Systems, Man, and Cybernetics, Part A. In Press, 2005.
  11. G. Levitin, Y.S. Dai, H. Ben-Haim, “Grid Performance and Reliability with Star Topology under Precedent Constraints”, IEEE Transactions on Reliability, In Press, 2005.
  12. Y.S. Dai, M. Xie, K.L. Poh, “Availability modelling and cost optimization for the grid resource management system”, IEEE Transactions on Systems, Man, and Cybernetics, Part A, In Press, 2005.
  13. Y.S. Dai, M. Palakal, S. Hartanto, X. Wang, Y. Guo, “A Grid-Based Pseudo-Cache Solution for MISD Biomedical Problems with High Confidentiality and Efficiency”, International Journal of Bioinformatics Research and Applications, In Press, 2005.
  14. G. Levitin, Y.S. Dai, “Service reliability and performance in grid system with star topology”, Reliability Engineering and System Safety. In Press, 2005.
  15. Y.S. Dai, “Reliability modelling and evaluation for wide-area distributed system”, INFORMATION, vol. 9, no 2, pp. 1-13, 2006.
  16. Y.S. Dai, X.L. Wang , “Optimal resource allocation on Grid systems for maximizing service reliability using a genetic algorithm”, Reliability Engineering and System Safety, In Press, 2005.
  17. Y.S. Dai, M. Xie, K.L. Poh, “Reliability of grid service systems”, Computers and Industrial Engineering. In Press, 2005.
  18. Y.S. Dai, T. Marshall , X.H. Guan, “Autonomic and Dependable Computing: Moving Towards a Model-Driven Approach”, Journal of Computer Science, In Press, 2005.
  19. Y. Karandikar, X.K. Zou, Y.S. Dai, “An effective key management approach to differential access control in dynamic environments”, Journal of Computer Science, In Press, 2005.
  20. Y.S. Dai, M. Xie, K.L. Poh and S.H. Ng, “A model for correlated failures in N-version programming”. IIE Transactions, vol. 36, no. 12, pp. 1183-1192, December, 2004.
  21. M. Xie, Y.S. Dai, K.L. Poh, C.D. Lai, “Distributed system availability in the case of imperfect debugging process”, International Journal of Industrial Engineering, vol. 11, no. 4, pp. 396-405, 2004.
  22. M. Xie, Y.S. Dai, K.L. Poh, C.D. Lai, “Optimal number of hosts in a distributed system based on cost criteria”, International Journal of Systems Science, vol. 35, no. 6, pp. 343-353, 2004.
  23. G.Q. Liu , M. Xie, Y.S. Dai and K.L. Poh, “On program and file assignment for distributed systems”, Computer Systems Science and Engineering, vol. 19, no. 1, pp. 39-48, 2004.
  24. Y.S. Dai, M. Xie, K.L. Poh and G.Q. Liu , “A study of service reliability and availability for distributed systems,” Reliability Engineering and System Safety, vol. 79, no. 1, pp. 103-112, Jan. 2003.
  25. Y.S. Dai, M. Xie, K.L. Poh and B. Yang , “Optimal testing-resource allocation with genetic algorithm for modular software systems”, Journal of Systems and Software, vol. 66, no. 1, pp. 47-55, Jan. 2003.
  26. G. Levitin, Y.S. Dai, M. Xie, K.L Poh, “Optimizing Survivability of Multi-State Systems with Multi-Level Protection by Multi-Processor Genetic Algorithm”, Reliability Engineering and System Safety, vol. 82, no. 1, pp. 93-104, Nov, 2003.
  27. C.D. Lai, M. Xie, K.L. Poh, Y.S. Dai, and P. Yang, “A model for availability analysis of distributed software/hardware systems”, Information and Software Technology, vol. 44, no. 6, pp. 343-350, June 2002.
  28. M. Liu, C. Wu, Y.S. Dai, “Genetic algorithm method based on knowledge for minimizing the number of tardy jobs in identical parallel machine scheduling problem,” Acta Electronica Sinica, vol. 27, no. 9, pp. 130-132, Sep. 1999. (in Chinese)

    Conference Proceeding Articles

  29. Y.S. Dai, X.L. Wang @, M. Xie, “A virtual modeling and a fast algorithm for Grid service reliability”, The 11th IEEE Pacific Rim Symposium on Dependable Computing (PRDC2005), IEEE Computer Press, China, Dec. 12-14, 2005, pp. 219-227.
  30. Y.S. Dai, X.K. Zou, Y.M. Guo @, “Grid-Based Information System with Fault Tolerance, Self-Healing and High-Performance”, the 10th Annual International Conference on Industrial Engineering Theory, Applications and Practice, Florida, December 4-7, 2005, pp. 455-460.
  31. Y.S. Dai, M. Xie, Q. Long@, S.H. Ng, “Uncertainty analysis in reliability modelling based on Bayesian analysis”, the 10th Annual International Conference on Industrial Engineering Theory, Applications and Practice, Florida, December 4-7, 2005, pp. 468-473.
  32. L. Xing, Y.S. Dai, “Reliability Evaluation using Various Decision Diagrams”, the 10th Annual International Conference on Industrial Engineering Theory, Applications and Practice, Florida, December 4-7, 2005, pp. 448-454.
  33. Y.S. Dai, “Autonomic computing and reliability improvement”, the 8th IEEE International Symposium on Object-oriented Real-time Distributed Computing (ISORC 05), May 18-20, 2005, Seattle, Washington, pp. 204-208.
  34. T. Marshall @, Y.S. Dai, “Reliability improvement and models in autonomic computing”, in the 11th International Conference on Parallel and Distributed Systems (ICPADS-2005) on RAMPDS, The Best Paper Award, 2005, vol. 2, pp. 468-473.
  35. Y. Karandikar @, X.K. Zou, Y.S. Dai, “Secure group communication based scheme for differential access control in dynamic environment”, in the 11th International Conference on Parallel and Distributed Systems (ICPADS-2005) on RAMPDS, 2005, vol. 2, pp. 448-453..
  36. Y.S. Dai, M. Xie, K.L. Poh, “Reliability Analysis of Grid Computing Systems”, The 9th IEEE Pacific Rim Symposium on Dependable Computing (PRDC2002), IEEE Computer Press, 2002, pp. 97-103.
  37. Y.S. Dai and K.L. Poh. “Solving the Network Interdiction Problem with Genetic Algorithms.” Proceedings of the Fourth Asia-Pacific Conference on Industrial Engineering and Management System (APIEMS-2002), Taiwan, pp. 151-154.
  38. Y.S. Dai, M. Xie and K.L. Poh, “A Fast Algorithm for Grid System Reliability”, Regional Inter-University Electrical & Electronic Engineering Conference 2003 (RIUPEEEC 2003), Hong Kong.
  39. Y.S. Dai and M. Xie, “Hierarchical Markov Reward Model for Availability Analysis and Optimization of the Grid Computing System”, Fourth International Conference on Mathematical Methods in Reliability (MMR04), June 21-25, 2004, Santa Fe, USA.

Dr.Xukai Zou

    Secure Group Communication (SGC).

  1. X. Zou and Y. Karandikar, A Novel Key Management Scheme for Highly Dynamic Collaborative Environments, Submitted to International Journal of Information Security (Springer).
  2. G. Hao@, N. V. Vinodchandran, B. Ramamurthy and X. Zou, A Balanced Key Tree Approach for Dynamic Secure Group Communication, Accepted by ICCCN 2005 FOURTEENTH INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS, October 17-19, 2005, CA, USA.
  3. P. Adusumilli@, X. Zou and B. Ramamurthy, DGKD: Distributed Group Key Distribution with Authentication Capability, Proceedings of the 2005 IEEE Workshop on Information Assurance (IAW), United States Military Academy, West Point, NY, 15-17 June 2005, pp. 286--293.
  4. X. Zou and A. Thukral, Key management, The Handbook of Information Security, Hossein Bidgoli, Editor-in-Chief, to be published by John Wiley \& Sons, Inc, October 2005.
  5. X. Zou, A. Thukral, and Y. Karandikar Secure Group Communication, Parallel and Distributed Computing: Evaluation, Improvement and Applications, Editors, Y. Dai, Y. Pan, and R. Raje, to be published by Nova Science Publishers, Sept., 2005.
  6. X. Zou, B. Ramamurthy and Spyros Ramamurthy, Secure Group Communication over Data Networks, Springer, ISBN: 0-387-22970-1 (The ebook ISBN: 0-387-22971-X), October 2004, pages 182 (Go to Springer for more information).
  7. X. Zou and B. Ramamurthy, A simple group Diffie-Hellman key agreement protocol without member serialization, Lecture Notes in Computer Science (LNCS), Springer-Verlag, Vol. 3314 (2004), pp. \ 725-731.
  8. X. Zou, B. Ramamurthy, and S. S. Magliveras, A GCD attack resistant CRTHACS for secure group communications, Proceedings of International Conference on Information Technology, ITCC 2004 (Poster), April 5 -7, 2004, Las Vegas, NV, USA, pp. \ 153--154.
  9. X. Zou and B. Ramamurthy, A block-free tree based group Diffie-Hellman key agreement protocol for secure group communication, Proceedings of International Conference on Parallel and Distributed Computing and Networks, Innsbruck, Austria, February 17-19, 2004, pp. \ 288--293.
  10. X. Zou, B. Ramamurthy and S. Magliveras, Efficient key management for secure group communication with bursty behavior, Proceedings of International Conference on Communication, Internet, and Information Technology, Virgin Islands, USA, November 2002, pp.\ 148--153.

    Secure Dynamic Conferencing (SDC)

  11. Y. Karandikar and X. Zou, A Novel Conference Key Management Solution for Secure Dynamic Conferencing, Submitted to International Journal of Security and Networks.
  12. P. Adusumilli and X. Zou, Symmetric Polynomial based Hierarchical Conference Key Management, Submitted to International Conference on Information and Communication Security (ICICS'05).
  13. P. Adusumilli@ and X. Zou, KTDCKM-SDC: A Distributed Conference Key Management Scheme for Secure Dynamic Conferencing, Proceedings of THE TENTH IEEE SYMPOSIUM ON COMPUTERS AND COMMUNICATIONS (ISCC), Cartagena, Spain, June 27-30, 2005, pp. 476--481.
  14. X. Zou, B. Ramamurthy and Spyros Ramamurthy, Secure Group Communication over Data Networks, Springer, ISBN: 0-387-22970-1 (The ebook ISBN: 0-387-22971-X), October 2004, pages 182 (Go to Springer for more information).
  15. X. Zou, S. Magliveras and B. Ramamurthy, Key Tree based Scalable Secure Dynamic Conferencing Schemes, Proceedings of International Conference on Parallel and Distributed Computing and Systems (PDCS 2004), MIT Cambridge, MA, USA, November 2004, pp. \ 61--65.
  16. X. Zou, S. Magliveras and B. Ramamurthy, A dynamic conference scheme extension with efficient burst operation, Congressus Numerantium, Vol. 158, 2002, pp.\ 83--92.

    Differential Access Control (DAC).

  17. Y. Karandikar@, X. Zou and Y. Dai, An Effective Key Management Approach to Differential Access Control in Dynamic Environments, Journal of Computer Science (in press), 2005.
  18. Y. Karandikar@, X. Zou and Y. Dai, Secure Group Communication Based Scheme for Differential Access Control in Dynamic Environments, Accepted by The 1st IEEE Workshop on Reliability and Autonomic Management In Parallel and Distributed Systems (RAMPDS-2005), 2005.

    Hierarchical Access Control (HAC).

  19. X. Zou, An Elegant Bottleneck-free General Hierarchical Access Control Scheme for Highly Dynamic Environments, Submitted to ACM Transactions on Information and System Security.
  20. Y. Karandikar and X. Zou and E. Bertino, An Efficient and Practical Solution to the Hierarchical Access Control Problem, Submitted to IEEE Transaction on Dependable and Secure Computing.
  21. X. Zou, B. Ramamurthy and Spyros Ramamurthy, Secure Group Communication over Data Networks, Springer, ISBN: 0-387-22970-1 (The ebook ISBN: 0-387-22971-X), October 2004, pages 182 (Go to Springer for more information).
  22. X. Zou, B. Ramamurthy, V. Variyam and R. K. Balachandran@, Algorithms for unified hierarchy based access control, Proceedings of International Conference on Communications, Internet, \& Information Technology (CIIT 2003), Scottsdale, AZ, USA, November 17-19, 2003, pp.\ 31--36.
  23. X. Zou, B. Ramamurthy and S. Magliveras, Chinese Remainder Theorem based hierarchical access control for secure group communications, Lecture Notes in Computer Science (LNCS), Springer-Verlag, vol. 2229 (2001), pp.\ 381--385.
  24. J.-C. Birget, X. Zou, G. Noubir and B. Ramamurthy, Hierarchy-based access control in distributed environments, Proceedings of IEEE International Conference on Communications, June 2001, Helsinki, Finland, pp.\ 229--233.

    SGC in wireless/mobile ad hoc networks (MANET).

  25. R. K. Balachandran@, B. Ramamurthy, X. Zou, and N. V. Vinodchandran, CRTDH: An Efficient Key Agreement Scheme for Secure Group Communications in Wireless Ad-Hoc Networks, Accepted by IEEE International Conference on Communication (ICC) 2005.
  26. A. Thukral, X. Zou, and B. Ramamurthy, AUTH-CRTDH: An LCM attack resistant CRTDH scheme with authentication capability, Submitted to The Third ACM Workshop on Security of Ad Hoc and Sensor Networks (ACM SASN'05) (in conjunction with ACM CCS'05).
  27. X. Zou, B. Ramamurthy and Spyros Ramamurthy, Secure Group Communication over Data Networks, Springer, ISBN: 0-387-22970-1 (The ebook ISBN: 0-387-22971-X), October 2004, pages 182 (Go to Springer for more information).

    Trusted Collaborative Computing (TCC) and Health/Medical Information System.

  28. X. Zou and Y. Dai, Secure Medical Data Repository and Regional Health Information Exchange Networks. In collaboration with Indiana University Medical School and VA Medical Center.
  29. Amandeep Thukral@ and Xukai Zou, Secure Group Instant Messaging based on Cryptographic Primitives, To appear in Lecture Notes in Computer Science (LNCS), Springer-Verlag, (2005).

    Selected Publications
    Books

  30. X. Zou, B. Ramamurthy and Spyros Ramamurthy, Secure Group Communication over Data Networks, Springer, ISBN: 0-387-22970-1 (The ebook ISBN: 0-387-22971-X), October 2004, pages 182 (Go to Springer for more information).
  31. X. Zou, C. Yang, H. Li and F. Liang, Intranet technologies and applications, ISBN 7-5606-0613-X, Xian Electronic Science and Technology University Publishing Press, August 1998.

    Book Chapters

  32. X. Zou, Public Key Standards: SSH (Secure Shell), The Handbook of Information Security, Hossein Bidgoli, Editor-in-Chief, to be published by John Wiley \& Sons, Inc, February 2005.
  33. X. Zou and A. Thukral, Key management, The Handbook of Information Security, Hossein Bidgoli, Editor-in-Chief, to be published by John Wiley \& Sons, Inc, February 2005.
  34. X. Zou, A. Thukral, and Y. Karandikar Secure Group Communication, Parallel and Distributed Computing: Evaluation, Improvement and Applications, Editors, Y. Dai, Y. Pan, and R. Raje, to be published by Nova Science Publishers, Sept., 2005.

    Journal Articles

  35. Y. Karandikar@, X. Zou and Y. Dai, An Effective Key Management Approach to Differential Access Control in Dynamic Environments, Journal of Computer Science (in press), 2005.
  36. Amandeep Thukral@ and Xukai Zou, Secure Group Instant Messaging based on Cryptographic Primitives, To appear in Lecture Notes in Computer Science (LNCS), Springer-Verlag, (2005).
  37. X. Zou and B. Ramamurthy, A simple group Diffie-Hellman key agreement protocol without member serialization, Lecture Notes in Computer Science (LNCS), Springer-Verlag, Vol. 3314 (2004), pp. \ 725-731.
  38. Q. Wu, Hua Xu, and X. Zou, An effective method for 3D geological modeling with multi-source data integration, Computers \& Geosciences, 31(1) , February 2005, pp. \ 35-43.
  39. X. Zou, B. Ramamurthy and S. Magliveras, Chinese Remainder Theorem based hierarchical access control for secure group communications, Lecture Notes in Computer Science (LNCS), Springer-Verlag, vol. 2229 (2001), pp.\ 381--385.
  40. X. Zou, S. Magliveras and B. Ramamurthy, A dynamic conference scheme extension with efficient burst operation, Congressus Numerantium, Vol. 158, 2002, pp.\ 83--92.
  41. X. Zou, An efficient approach to compute the edit distance and edit path for char/(Chinese character) string. Computer Research and Development, 33 (8), 1996, pp 574--581.
  42. X. Zou, An efficient edit distance and edit path computation approach. Mini-Micro Systems, 17(7), 1996, pp 72--76.
  43. X. Zou, An efficient parallel approximate approach to char/(Chinese characters) string pattern matching. Journal of Advanced Software Research, 2(2), 1995, pp 198--203.
  44. X. Zou, A fast approach to char/(Chinese characters) string pattern matching allowing errors. Journal of Advanced Software Research, 2(2), 1995, pp 147--152.
  45. X. Zou, An approach for parallel string pattern matching allowing errors. Computer Research and Development, 32(2), 1995, pp 34--38.
  46. X. Zou, An efficient parallel approximate approach to char/(Chinese characters) string pattern matching. Journal of Software, 6(8), 1995, pp 463--468.
  47. X. Zou, An optimal parallel Chinese character/char string searching approach. Journal of Chinese Information. 1, 1995.
  48. X. Zou, An efficient approach to automatic checking and correction of spelling errors in compilation. Journal of Zhengzhou University, 27(1), 1995.
  49. X. Zou and S. Wang, A fast approach to char/(Chinese characters) string pattern matching allowing errors. Journal of Software, 5(10), 1994, pp 55--59.
  50. X. Zou, An optimal parallel string searching approach. Journal of Zhengzhou University, 26(1), 1994, pp 41--45.
  51. X. Zou, An fast pattern matching approach with scaling. Journal of Zhengzhou University, 26(3), 1994,
  52. X. Zou, String searching: theory and practice. in Proceedings of the Fourth young computer scientist annual conference, China, 12, 1994.
  53. X. Zou, A fast approach to char/(Chinese character) string pattern matching. Mini-Micro Systems. 14(11), 1993, pp 49--53.
  54. X. Zou and Y. Guo, A reliable microcomputer communication approach. Journal of Zhengzhou University, 25(3), 1993, pp24--28.
  55. X. Zou, Notes on McCabe approach measuring program complexity. Henan Electronics Technology, 4(1), 1993.
  56. X. Zou, An efficient parallel approximate approach to char/Chinese character string searching, Journal of Advanced Software Research, 2(2), 1995, pp.\ 198--203.
  57. X. Zou, A fast approach to char/Chinese characters text searching allowing errors, Journal of Advanced Software Research, 2(2), 1995, pp.\ 147--152.

    Refered Conference Proceeding Papers

  58. G. Hao@, N. V. Vinodchandran, B. Ramamurthy and X. Zou, A Balanced Key Tree Approach for Dynamic Secure Group Communication, Accepted by ICCCN 2005 FOURTEENTH INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS, October 17-19, 2005, CA, USA.
  59. P. Adusumilli@, X. Zou and B. Ramamurthy, DGKD: Distributed Group Key Distribution with Authentication Capability, Proceedings of the 2005 IEEE Workshop on Information Assurance (IAW), United States Military Academy, West Point, NY, 15-17 June 2005, pp. 286--293.
  60. Y. Karandikar@, X. Zou and Y. Dai, Secure Group Communication Based Scheme for Differential Access Control in Dynamic Environments, Accepted by The 1st IEEE Workshop on Reliability and Autonomic Management In Parallel and Distributed Systems (RAMPDS-2005), 2005.
  61. P. Adusumilli@ and X. Zou, KTDCKM-SDC: A Distributed Conference Key Management Scheme for Secure Dynamic Conferencing, Proceedings of THE TENTH IEEE SYMPOSIUM ON COMPUTERS AND COMMUNICATIONS (ISCC), Cartagena, Spain, June 27-30, 2005, pp. 476--481.
  62. R. K. Balachandran@, B. Ramamurthy, X. Zou, and N. V. Vinodchandran, CRTDH: An Efficient Key Agreement Scheme for Secure Group Communications in Wireless Ad-Hoc Networks, Accepted by IEEE International Conference on Communication (ICC) 2005.
  63. X. Zou, S. Magliveras and B. Ramamurthy, Key Tree based Scalable Secure Dynamic Conferencing Schemes, Proceedings of International Conference on Parallel and Distributed Computing and Systems (PDCS 2004), MIT Cambridge, MA, USA, November 2004, pp. \ 61--65.
  64. X. Zou, B. Ramamurthy, and S. S. Magliveras, A GCD attack resistant CRTHACS for secure group communications, Proceedings of International Conference on Information Technology, ITCC 2004 (Poster), April 5 -7, 2004, Las Vegas, NV, USA, pp. \ 153--154.
  65. X. Zou and B. Ramamurthy, A block-free tree based group Diffie-Hellman key agreement protocol for secure group communication, Proceedings of International Conference on Parallel and Distributed Computing and Networks, Innsbruck, Austria, February 17-19, 2004, pp. \ 288--293.
  66. X. Zou, B. Ramamurthy, V. Variyam and R. K. Balachandran@, Algorithms for unified hierarchy based access control, Proceedings of International Conference on Communications, Internet, \& Information Technology (CIIT 2003), Scottsdale, AZ, USA, November 17-19, 2003, pp.\ 31--36.
  67. X. Zou, B. Ramamurthy and S. Magliveras, Efficient key management for secure group communication with bursty behavior, Proceedings of International Conference on Communication, Internet, and Information Technology, Virgin Islands, USA, November 2002, pp.\ 148--153.
  68. X. Zou, B. Ramamurthy and S. Magliveras, Routing techniques for wireless ad hoc networks-- classification and comparison, Proceedings of the Sixth World Multiconference on Systemics, Cybernetics, and Informatics, Orlando, Florida, USA, July, 2002, pp. \ 352-357.
  69. J.-C. Birget, X. Zou, G. Noubir and B. Ramamurthy, Hierarchy-based access control in distributed environments, Proceedings of IEEE International Conference on Communications, June 2001, Helsinki, Finland, pp.\ 229--233.