[IEEE The 2002 International Conference on Control and Automation, 2002. ICCA. Final Program and Book of Abstracts. - Xiamen, Fujian Province, China (June 16-19, 2002)] The 2002 International Conference on Control and Automation, 2002. ICCA. Final Program and Book of Abstracts. - Robust H-infinity control for the delta operator formulated uncertain systems with circular pole constraints