424 research outputs found
The Immune System: the ultimate fractionated cyber-physical system
In this little vision paper we analyze the human immune system from a
computer science point of view with the aim of understanding the architecture
and features that allow robust, effective behavior to emerge from local sensing
and actions. We then recall the notion of fractionated cyber-physical systems,
and compare and contrast this to the immune system. We conclude with some
challenges.Comment: In Proceedings Festschrift for Dave Schmidt, arXiv:1309.455
A finder and representation system for knowledge carriers based on granular computing
In one of his publications Aristotle states ”All human beings by their nature desire to know” [Kraut 1991]. This desire is initiated the day we are born and accompanies us for the rest of our life. While at a young age our parents serve as one of the principle sources for knowledge, this changes over the course of time. Technological advances and particularly the introduction of the Internet, have given us new possibilities to share and access knowledge from almost anywhere at any given time. Being able to access and share large collections of written down knowledge is only one part of the equation. Just as important is the internalization of it, which in many cases can prove to be difficult to accomplish. Hence, being able to request assistance from someone who holds the necessary knowledge is of great importance, as it can positively stimulate the internalization procedure. However, digitalization does not only provide a larger pool of knowledge sources to choose from but also more people that can be potentially activated, in a bid to receive personalized assistance with a given problem statement or question. While this is beneficial, it imposes the issue that it is hard to keep track of who knows what. For this task so-called Expert Finder Systems have been introduced, which are designed to identify and suggest the most suited candidates to provide assistance. Throughout this Ph.D. thesis a novel type of Expert Finder System will be introduced that is capable of capturing the knowledge users within a community hold, from explicit and implicit data sources. This is accomplished with the use of granular computing, natural language processing and a set of metrics that have been introduced to measure and compare the suitability of candidates. Furthermore, are the knowledge requirements of a problem statement or question being assessed, in order to ensure that only the most suited candidates are being recommended to provide assistance
Supporting Temporal Reasoning by Mapping Calendar Expressions to Minimal Periodic Sets
In the recent years several research efforts have focused on the concept of
time granularity and its applications. A first stream of research investigated
the mathematical models behind the notion of granularity and the algorithms to
manage temporal data based on those models. A second stream of research
investigated symbolic formalisms providing a set of algebraic operators to
define granularities in a compact and compositional way. However, only very
limited manipulation algorithms have been proposed to operate directly on the
algebraic representation making it unsuitable to use the symbolic formalisms in
applications that need manipulation of granularities.
This paper aims at filling the gap between the results from these two streams
of research, by providing an efficient conversion from the algebraic
representation to the equivalent low-level representation based on the
mathematical models. In addition, the conversion returns a minimal
representation in terms of period length. Our results have a major practical
impact: users can more easily define arbitrary granularities in terms of
algebraic operators, and then access granularity reasoning and other services
operating efficiently on the equivalent, minimal low-level representation. As
an example, we illustrate the application to temporal constraint reasoning with
multiple granularities.
From a technical point of view, we propose an hybrid algorithm that
interleaves the conversion of calendar subexpressions into periodical sets with
the minimization of the period length. The algorithm returns set-based
granularity representations having minimal period length, which is the most
relevant parameter for the performance of the considered reasoning services.
Extensive experimental work supports the techniques used in the algorithm, and
shows the efficiency and effectiveness of the algorithm
HIERARCHICAL-GRANULARITY HOLONIC MODELLING
This thesis aims to introduce an agent-based system engineering approach,
named Hierarchical-Granularity Holonic Modelling, to support intelligent
information processing at multiple granularity levels. The focus is especially
on complex hierarchical systems.
Nowadays, due to ever growing complexity of information systems and
processes, there is an increasing need of a simple self-modular computational
model able to manage data and perform information granulation at different
resolutions (i.e., both spatial and temporal). The current literature lacks to
provide such a methodology. To cite a relevant example, the object-oriented
paradigm is suitable for describing a system at a given representation level;
notwithstanding, further design effort is needed if a more synthetical of more
analytical view of the same system is required.
In the literature, the agent paradigm represents a viable solution in complex
systems modelling; in particular, Multi-Agent Systems have been applied with
success in a countless variety of distributed intelligence settings. Current
agent-oriented implementations however suffer from an apparent dichotomy
between agents as intelligent entities and agents\u2019 structures as superimposed
hierarchies of roles within a given organization. The agents\u2019 architectures are
often rigid and require intense re-engineering when the underpinning ontology
is updated to cast new design criteria.
The latest stage in the evolution of modelling frameworks is represented by
Holonic Systems, based on the notion of \u2018holon\u2019 and \u2018holarchy\u2019 (i.e.,
hierarchy of holons). A holon, just like an agent, is an intelligent entity able to
interact with the environment and to take decisions to solve a specific
problem. Contrarily to agent, holon has the noteworthy property of playing the
role of a whole and a part at the same time. This reflects at the organizational
level: holarchy functions first as autonomous wholes in supra-ordination to
their parts, secondly as dependent parts in sub-ordination to controls on higher
levels, and thirdly in coordination with their local environment.
These ideas were originally devised by Arthur Koestler in 1967. Since then,
Holonic Systems have gained more and more credit in various fields such as
Biology, Ecology, Theory of Emergence and Intelligent Manufacturing.
Notwithstanding, with respect to these disciplines, fewer works on Holonic
Systems can be found in the general framework of Artificial and
Computational Intelligence. Moreover, the distance between theoretic models
and actual implementation is still wide open.
In this thesis, starting from the Koestler\u2019s original idea, we devise a novel
agent-inspired model that merges intelligence with the holonic structure at
multiple hierarchical-granularity levels. This is made possible thanks to a rule-based
knowledge recursive representation, which allows the holonic agent to
carry out both operating and learning tasks in a hierarchy of granularity levels.
The proposed model can be directly used in terms of hardware/software
applications. This endows systems and software engineers with a modular and
scalable approach when dealing with complex hierarchical systems. In order
to support our claims, exemplar experiments of our proposal are shown and
prospective implications are commented
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