Self-organisation is increasingly being regarded as an effective approach to tackle
modern systems complexity. The self-organisation approach allows the development of systems exhibiting complex dynamics and adapting to environmental
perturbations without requiring a complete knowledge of the future surrounding
conditions.
However, the development of self-organising systems (SOS) is driven by different principles with respect to traditional software engineering. For instance,
engineers typically design systems combining smaller elements where the composition rules depend on the reference paradigm, but typically produce predictable
results. Conversely, SOS display non-linear dynamics, which can hardly be captured by deterministic models, and, although robust with respect to external
perturbations, are quite sensitive to changes on inner working parameters.
In this thesis, we describe methodological aspects concerning the early-design
stage of SOS built relying on the Multiagent paradigm: in particular, we refer
to the A&A metamodel, where MAS are composed by agents and artefacts, i.e.
environmental resources. Then, we describe an architectural pattern that has
been extracted from a recurrent solution in designing self-organising systems:
this pattern is based on a MAS environment formed by artefacts, modelling
non-proactive resources, and environmental agents acting on artefacts so as to
enable self-organising mechanisms. In this context, we propose a scientific approach for the early design stage of the engineering of self-organising systems:
the process is an iterative one and each cycle is articulated in four stages, modelling, simulation, formal verification, and tuning. During the modelling phase
we mainly rely on the existence of a self-organising strategy observed in Nature
and, hopefully encoded as a design pattern. Simulations of an abstract system model are used to drive design choices until the required quality properties
are obtained, thus providing guarantees that the subsequent design steps would
lead to a correct implementation. However, system analysis exclusively based
on simulation results does not provide sound guarantees for the engineering of
complex systems: to this purpose, we envision the application of formal verification techniques, specifically model checking, in order to exactly characterise the
system behaviours. During the tuning stage parameters are tweaked in order to
meet the target global dynamics and feasibility constraints.
In order to evaluate the methodology, we analysed several systems: in this
thesis, we only describe three of them, i.e. the most representative ones for
each of the three years of PhD course. We analyse each case study using the
presented method, and describe the exploited formal tools and techniques.
| Identifer | oai:union.ndltd.org:unibo.it/oai:amsdottorato.cib.unibo.it:927 |
| Date | 07 April 2008 |
| Creators | Gardelli, Luca <1980> |
| Contributors | Natali, Antonio |
| Publisher | Alma Mater Studiorum - Università di Bologna |
| Source Sets | Università di Bologna |
| Language | English |
| Detected Language | English |
| Type | Doctoral Thesis, PeerReviewed |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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