Abstract:
Today, software often runs as embedded systems in mobile devices or distributed over networks. Thus, a software system has to deal with changing demands and uncertainties in the environment. Within embedded systems disturbances from the environment have to be expected. Through the distribution over several devices, not only non-functional properties, like the load of a service, may change, but also the interacting system parts may be substituted during run-time. Feedback, as it is used in control theory, deals with uncertainties and compensation of disturbances. In software control loops can be used in order to implement self-adaptation, self-healing, or self-optimization. The feedback, which is used in control loops, also o ers the possibility to deal with disturbances that stem from the environment of the software. Although feedback is often implemented in software there is currently no support for an explicit modeling of control loops in software. Without explicit models the interaction of control loops cannot be shown. So an analysis of the structure and behavior of control loops within complex systems is almost impossible. This thesis introduces modeling concepts for the explicit modeling of feedback. Thereby the concept of feedback is not only transferred from control theory to software, but also supplemented with concepts that satisfy special needs of software. The introduced modeling concepts are formalized in an UML pro le. The presented concepts additionally enable the design of control loops that apply structural adaptations to software systems. Through the formulation of warning signal for control loops that are not well-formed, this thesis creates the basis for the analysis of the interaction of control loops.
BibTeX file
title = { Modeling of Feedback in Self-Adaptive Systems },
year = { 2009 },
abstract = { Today, software often runs as embedded systems in mobile devices or distributed over networks. Thus, a software system has to deal with changing demands and uncertainties in the environment. Within embedded systems disturbances from the environment have to be expected. Through the distribution over several devices, not only non-functional properties, like the load of a service, may change, but also the interacting system parts may be substituted during run-time. Feedback, as it is used in control theory, deals with uncertainties and compensation of disturbances. In software control loops can be used in order to implement self-adaptation, self-healing, or self-optimization. The feedback, which is used in control loops, also o ers the possibility to deal with disturbances that stem from the environment of the software. Although feedback is often implemented in software there is currently no support for an explicit modeling of control loops in software. Without explicit models the interaction of control loops cannot be shown. So an analysis of the structure and behavior of control loops within complex systems is almost impossible. This thesis introduces modeling concepts for the explicit modeling of feedback. Thereby the concept of feedback is not only transferred from control theory to software, but also supplemented with concepts that satisfy special needs of software. The introduced modeling concepts are formalized in an UML pro le. The presented concepts additionally enable the design of control loops that apply structural adaptations to software systems. Through the formulation of warning signal for control loops that are not well-formed, this thesis creates the basis for the analysis of the interaction of control loops. },
month = { 10 },
school = { Hasso-Plattner-Institut für Softwaresystemtechnik, Universität Potsdam }
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