[26 May 2014] A bachelor student at RTSLAB was awarded the best thesis
award from IDA - Simon Andersson. more ...
[31 May 2012] A masters student at RTSLAB was awarded the best thesis
award from IDA - Ulf Magnusson. more ...
[27 February 2008] A masters student at RTSLAB was awarded the best thesis
award from IDA - Johan Sigholm. more ...
[03 March 2004] A masters student at RTSLAB was awarded the best thesis
award from IDA - Tobias Chyssler. more ...
[01 Jul 2003] For second year in a row a masters student at RTSLAB was awarded the best thesis
award from SNART - Mehdi Amirijoo. more ...
Master Thesis - Past Projects - Abstract
Adaptive Control of QoS-Priority Partitioned Real-Time Systems
Many computer applications of today offer customers services, which
can vary in importance and quality. For example, different importance
levels are connected to different prices with services like video
streaming, which partly can tolerate low quality, i.e., lost
information or delays in computation. Sometimes systems become
overloaded and cannot process all the work assigned to them. The use
of control theory can let the systems lower service quality where it
is allowed and, thereby, execute as much work as possible. In this
thesis we adress a problem discovered in a previous study, where the
system under control was observed to change characteristics as the
workload of the system changed. This leads to a controller, which was
tuned for a certain workload, showing bad performance in terms of
settling time for the controlled variable after transient overloads.
The approach presented in this thesis is based on adaptive control
theory where the system characteristics are estimated and controllers
are tuned during run-time to give the system the desired performance
independent of the workload. The results show an improved performance
compared to a fixed-parameter controller where no adaptation of the
controller is carried out. The improved performance of the adaptive
approach was observed in halved settling times for the controlled
variable with workloads that the fixed-parameter controller was not
tuned for. Further a discussion is presented on the shortcomings of
the evaluated approach and future work on this subject.
Keywords: Adaptive control, Quality of Service, Real-time system
Author(s): Per Brännström
Contact: Mehdi Amirijoo
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