Marcus Tylutki Karl N. Levitt Mitigating Distributed Denial of Service Attacks Using a Proportional-Integral-Derivative Controller. 1-16 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2820&spage=1 2003 conf/raid/2003 RAID db/conf/raid/raid2003.html#TylutkiL03