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Analysis of Buffer Delay in Web-Server Control

Kjaer, Martin Ansbjerg LU and Robertsson, Anders LU (2010) American Control Conference, 2010 In 2010 American Control Conference p.1047-1052
Abstract
This paper addresses a problem related to control of web servers. Due to architectual issues, relevant measurements can only be taken over a limited part of the server system, which leaves the controller unaware of what happens in buffers proceeding the actual web-server (for instance, in the TCP/IP layers). In earlier presented work we modeled such a system and proved that the unmeasured buffering turned a measurement of an input disturbance into a state-dependent variable. In this paper we investigate how these new properties effect a traditional control design consisting of feedback in combination with a feed-forward mechanism. The stability analysis suggests that under certain circumstances, the system enters limit cycles due to the... (More)
This paper addresses a problem related to control of web servers. Due to architectual issues, relevant measurements can only be taken over a limited part of the server system, which leaves the controller unaware of what happens in buffers proceeding the actual web-server (for instance, in the TCP/IP layers). In earlier presented work we modeled such a system and proved that the unmeasured buffering turned a measurement of an input disturbance into a state-dependent variable. In this paper we investigate how these new properties effect a traditional control design consisting of feedback in combination with a feed-forward mechanism. The stability analysis suggests that under certain circumstances, the system enters limit cycles due to the feedback mechanism introduced by the designed feed-forward controller. We verify the analysis by both simulations and experiments. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
2010 American Control Conference
pages
1047 - 1052
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
conference name
American Control Conference, 2010
external identifiers
  • wos:000287187901072
  • scopus:77957803927
ISSN
0743-1619
language
English
LU publication?
yes
id
48d1d552-b635-467d-a8cb-eb431994c065 (old id 1918189)
date added to LUP
2011-05-13 15:45:43
date last changed
2018-05-29 12:30:15
@inproceedings{48d1d552-b635-467d-a8cb-eb431994c065,
  abstract     = {This paper addresses a problem related to control of web servers. Due to architectual issues, relevant measurements can only be taken over a limited part of the server system, which leaves the controller unaware of what happens in buffers proceeding the actual web-server (for instance, in the TCP/IP layers). In earlier presented work we modeled such a system and proved that the unmeasured buffering turned a measurement of an input disturbance into a state-dependent variable. In this paper we investigate how these new properties effect a traditional control design consisting of feedback in combination with a feed-forward mechanism. The stability analysis suggests that under certain circumstances, the system enters limit cycles due to the feedback mechanism introduced by the designed feed-forward controller. We verify the analysis by both simulations and experiments.},
  author       = {Kjaer, Martin Ansbjerg and Robertsson, Anders},
  booktitle    = {2010 American Control Conference},
  issn         = {0743-1619},
  language     = {eng},
  pages        = {1047--1052},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  title        = {Analysis of Buffer Delay in Web-Server Control},
  year         = {2010},
}