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In the last two decades, the advent of wireless networking
technology and the achievements in the miniaturization of electronic
devices have set new trends in distributed computing. This
ultimately enables a new paradigm for embedding mobile users in
intelligent environments that support them in their interactions
with their local physical surrounding. This vision is called Ambient
Intelligence (AmI). There are still many challenges ahead on the way
towards the realization of AmI. One question that is central to the
entire concept is: How can we render AmI systems self-organizing
such that they can indeed disappear in our environment without
creating a massive administrative problem?
In this book, we propose a model for a dedicated AmI infrastructure
that supports the user in his interaction with his physical
environment and with external entities. This infrastructure is
called Ad hoc Service Grid (ASG) and provides wireless services in a
decentralized and self-organizing fashion. We identify three
distinct problems associated with self-organized service
provisioning in the ASG model and propose algorithms and protocols
that solve them. The problem that is at the center of our work is
the self-organized replication and distribution of arbitrary
services in an ASG. A set of algorithms is presented that solves
this problem in a completely distributed way. The two other problems
we tackle are the discovery and lookup of dynamically distributed
service replicas and the reconciliation among a dynamic group of
replicas. Together, the mechanisms we propose lay the foundation for
a general AmI software platform. We will derive the architecture of
such a Serviceware from these mechanisms. Detailed experimental
results are presented that show the validity of our concepts and
identify ways for tailoring our algorithms and protocols to the
requirements of specific applications. Furthermore, we propose a new
general model and a classification methodology for self-organizing
software systems. We employ this model to evaluate our own
solutions.
The focus of the research work presented in this book is on the
global-scale interactions in an AmI system. We call this the
macro-level of interactions to separate it from the focus of most
current research projects. These projects concentrate more on
adaptations at the micro-level, pertaining to the internal
structures of specific applications and services. Our work
complements these efforts by providing solutions for structuring AmI
systems externally, for example by distributing a group of service
replicas within an ASG network.
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