1,895 research outputs found
A Provenance Tracking Model for Data Updates
For data-centric systems, provenance tracking is particularly important when
the system is open and decentralised, such as the Web of Linked Data. In this
paper, a concise but expressive calculus which models data updates is
presented. The calculus is used to provide an operational semantics for a
system where data and updates interact concurrently. The operational semantics
of the calculus also tracks the provenance of data with respect to updates.
This provides a new formal semantics extending provenance diagrams which takes
into account the execution of processes in a concurrent setting. Moreover, a
sound and complete model for the calculus based on ideals of series-parallel
DAGs is provided. The notion of provenance introduced can be used as a
subjective indicator of the quality of data in concurrent interacting systems.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432
A Developmental Organization for Robot Behavior
This paper focuses on exploring how learning and development can be structured in synthetic (robot) systems. We present a developmental assembler for constructing reusable and temporally extended actions in a sequence. The discussion adopts the traditions
of dynamic pattern theory in which behavior
is an artifact of coupled dynamical systems
with a number of controllable degrees of freedom. In our model, the events that delineate
control decisions are derived from the pattern
of (dis)equilibria on a working subset of sensorimotor policies. We show how this architecture can be used to accomplish sequential
knowledge gathering and representation tasks
and provide examples of the kind of developmental milestones that this approach has
already produced in our lab
Toward a fundamental groupoid for the stable homotopy category
This very speculative sketch suggests that a theory of fundamental groupoids
for tensor triangulated categories could be used to describe the ring of
integers as the singular fiber in a family of ring-spectra parametrized by a
structure space for the stable homotopy category, and that Bousfield
localization might be part of a theory of `nearby' cycles for stacks or
orbifolds.Comment: This is the version published by Geometry & Topology Monographs on 18
April 200
Limit sets for modules over groups on CAT(0) spaces -- from the Euclidean to the hyperbolic
The observation that the 0-dimensional Geometric Invariant
of Bieri-Neumann-Strebel-Renz can be interpreted as a horospherical limit set
opens a direct trail from Poincar\'e's limit set of a
discrete group of M\"obius transformations (which contains the
horospherical limit set of ) to the roots of tropical geometry
(closely related to when G is abelian). We explore this
trail by introducing the horospherical limit set, , of a G-module
A when G acts by isometries on a proper CAT(0) metric space M. This is a subset
of the boundary at infinity of M. On the way we meet instances where is the set of all conical limit points, the complement of a spherical
building, the complement of the radial projection of a tropical variety, or
(via the Bieri-Neumann-Strebel invariant) where it is closely related to the
Thurston norm.Comment: This is the final published versio
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