31,202 research outputs found
Endurant Types in Ontology-Driven Conceptual Modeling: Towards OntoUML 2.0
For over a decade now, a community of researchers has contributed
to the development of the Unified Foundational Ontology (UFO)
- aimed at providing foundations for all major conceptual modeling constructs.
This ontology has led to the development of an Ontology-Driven
Conceptual Modeling language dubbed OntoUML, reflecting the ontological
micro-theories comprising UFO. Over the years, UFO and OntoUML
have been successfully employed in a number of academic, industrial and
governmental settings to create conceptual models in a variety of different
domains. These experiences have pointed out to opportunities of
improvement not only to the language itself but also to its underlying
theory. In this paper, we take the first step in that direction by revising
the theory of types in UFO in response to empirical evidence. The
new version of this theory shows that many of the meta-types present
in OntoUML (differentiating Kinds, Roles, Phases, Mixins, etc.) should
be considered not as restricted to Substantial types but instead should
be applied to model Endurant Types in general, including Relator types,
Quality types and Mode types. We also contribute a formal characterization
of this fragment of the theory, which is then used to advance a
metamodel for OntoUML 2.0. Finally, we propose a computational support
tool implementing this updated metamodel
Particle Learning and Smoothing
Particle learning (PL) provides state filtering, sequential parameter
learning and smoothing in a general class of state space models. Our approach
extends existing particle methods by incorporating the estimation of static
parameters via a fully-adapted filter that utilizes conditional sufficient
statistics for parameters and/or states as particles. State smoothing in the
presence of parameter uncertainty is also solved as a by-product of PL. In a
number of examples, we show that PL outperforms existing particle filtering
alternatives and proves to be a competitor to MCMC.Comment: Published in at http://dx.doi.org/10.1214/10-STS325 the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Particle Learning for General Mixtures
This paper develops particle learning (PL) methods for the estimation of general mixture models. The approach is distinguished from alternative particle filtering methods in two major ways. First, each iteration begins by resampling particles according to posterior predictive probability, leading to a more efficient set for propagation. Second, each particle tracks only the "essential state vector" thus leading to reduced dimensional inference. In addition, we describe how the approach will apply to more general mixture models of current interest in the literature; it is hoped that this will inspire a greater number of researchers to adopt sequential Monte Carlo methods for fitting their sophisticated mixture based models. Finally, we show that PL leads to straight forward tools for marginal likelihood calculation and posterior cluster allocation.Business Administratio
Fast method for the determination of short-chain-length polyhydroxyalkanoates (scl-PHAs) in bacterial samples by In Vial-Thermolysis (IVT)
none8siA new method based on the GC–MS analysis of thermolysis products obtained by treating bacterial
samples at a high temperature (above 270 C) has been developed. This method, here named “In-Vial-
Thermolysis” (IVT), allowed for the simultaneous determination of short-chain-length polyhydrox-
yalkanoates (scl-PHA) content and composition. The method was applied to both single strains and
microbial mixed cultures (MMC) fed with different carbon sources.
The IVT procedure provided similar analytical performances compared to previous Py-GC–MS and Py-
GC-FID methods, suggesting a similar application for PHA quantitation in bacterial cells. Results from the
IVT procedure and the traditional methanolysis method were compared; the correlation between the
two datasets was
fit for the purpose, giving a R2 of 0.975. In search of further simplification, the rationale
of IVT was exploited for the development of a “field method” based on the titration of thermolyzed
samples with sodium hydrogen carbonate to quantify PHA inside bacterial cells. The accuracy of the IVT
method was
fit for the purpose.
These results lead to the possibility for the on-line measurement of PHA productivity. Moreover, they
allow for the fast and inexpensive quantification/characterization of PHA for biotechnological process
control, as well as investigation over various bacterial communities and/or feeding strategies.mixedF. Abbondanzi; G. Biscaro; G. Carvalho; L. Favaro; P. Lemos; M. Paglione; C. Samorì; C. TorriF. Abbondanzi; G. Biscaro; G. Carvalho; L. Favaro; P. Lemos; M. Paglione; C. Samorì; C. Torr
Iliopsoas Release for Internal Snapping Hip using a Minimally Open Medial Hip Approach-Case Report
Internal snapping hip is a recognized cause of hip pain caused by recurrent subluxation of the
iliopsoas tendon. When conservative treatment fails, surgical release of the iliopsoas tendon may be
indicated using an arthroscopic or open hip approach. Results have been better with arthroscopic
release. We report a case of a 32-year-old active female with a painful internal snapping hip. The
right hip extension from a flexed position produced a strong and audible snap. A tenotomy of the
iliopsoas in combination with a resection of the lesser trochanter was performed, using a limited
medial hip approach different than the one described by Ludloff or Ferguson. The pain and snapping
phenomenon were solved; however, a slight heterotopic ossification, as well as a weakness in the
flexion of the hip was noted after the procedure, with no functional limitation. The minimally invasive
medial hip approach appears to be a simple, reproducible and successful operation for the treatment
of an internal snapping hip caused by the iliopsoas tendon, namely in orthopaedics departments with
limited experience in hip arthroscopic approach, but it is not superior to arthroscopic release.info:eu-repo/semantics/publishedVersio
Thermal evolution of hybrid stars within the framework of a nonlocal Nambu--Jona-Lasinio model
We study the thermal evolution of neutron stars containing deconfined quark
matter in their core. Such objects are generally referred to as quark-hybrid
stars. The confined hadronic matter in their core is described in the framework
of non-linear relativistic nuclear field theory. For the quark phase we use a
non-local extension of the SU(3) Nambu Jona-Lasinio model with vector
interactions. The Gibbs condition is used to model phase equilibrium between
confined hadronic matter and deconfined quark matter. Our study indicates that
high-mass neutron stars may contain between 35 and 40 % deconfined quark-hybrid
matter in their cores. Neutron stars with canonical masses of around would not contain deconfined quark matter. The central proton
fractions of the stars are found to be high, enabling them to cool rapidly.
Very good agreement with the temperature evolution established for the neutron
star in Cassiopeia A (Cas A) is obtained for one of our models (based on the
popular NL3 nuclear parametrization), if the protons in the core of our stellar
models are strongly paired, the repulsion among the quarks is mildly repulsive,
and the mass of Cas A has a canonical value of .Comment: 10 pages, 7 figure
Detection of Exotic Massive Hadrons in Ultra High Energy Cosmic Ray Telescopes
We investigate the detection of exotic massive strongly interacting hadrons
(uhecrons) in ultra high energy cosmic ray telescopes. The conclusion is that
experiments such as the Pierre Auger Observatory have the potential to detect
these particles. It is shown that uhecron showers have clear distinctive
features when compared to proton and nuclear showers. The simulation of uhecron
air showers, and its detection and reconstruction by fluorescence telescopes is
described. We determine basic cuts in observables that will separate uhecrons
from the cosmic ray bulk, assuming this is composed by protons. If these are
composed by heavier nucleus the separation will be much improved. We also
discuss photon induced showers. The complementarity between uhecron detection
in accelerator experiments is discussed.Comment: 9 page 9 figure
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