Direct Adaptive Control of a Web Cache System

Ying Lu, Tarek Abdelzaher, Gang Tao

Research output: Contribution to journalConference articlepeer-review


For a 2-class content web cache, with the measured relative cache hit ratios as output and the content class storage space ratios as input, a dynamic model is derived and supported by experiment verification, to capture the dynamic nature of a web cache system. To deal with system parameter uncertainties and noises in controlling the hit rate ratio between two classes, a direct adaptive feedback control approach is employed. Two adaptive control designs are studied: a deterministic design for handling parameter uncertainties, and a stochastic design for compensating system noises. Experiment results are presented to show that both designs are capable of improving system performance, while a stochastic design performs better. Experiment results from a fixed control design and an open-loop control design are also given as comparison to show that adaptive designs are more promising for web cache system applications.

Original languageEnglish (US)
Pages (from-to)1625-1630
Number of pages6
JournalProceedings of the American Control Conference
StatePublished - 2003
Externally publishedYes
Event2003 American Control Conference - Denver, CO, United States
Duration: Jun 4 2003Jun 6 2003

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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