4,718 research outputs found
A Declarative Semantics for CLP with Qualification and Proximity
Uncertainty in Logic Programming has been investigated during the last
decades, dealing with various extensions of the classical LP paradigm and
different applications. Existing proposals rely on different approaches, such
as clause annotations based on uncertain truth values, qualification values as
a generalization of uncertain truth values, and unification based on proximity
relations. On the other hand, the CLP scheme has established itself as a
powerful extension of LP that supports efficient computation over specialized
domains while keeping a clean declarative semantics. In this paper we propose a
new scheme SQCLP designed as an extension of CLP that supports qualification
values and proximity relations. We show that several previous proposals can be
viewed as particular cases of the new scheme, obtained by partial
instantiation. We present a declarative semantics for SQCLP that is based on
observables, providing fixpoint and proof-theoretical characterizations of
least program models as well as an implementation-independent notion of goal
solutions.Comment: 17 pages, 26th Int'l. Conference on Logic Programming (ICLP'10
A Transformation-based Implementation for CLP with Qualification and Proximity
Uncertainty in logic programming has been widely investigated in the last
decades, leading to multiple extensions of the classical LP paradigm. However,
few of these are designed as extensions of the well-established and powerful
CLP scheme for Constraint Logic Programming. In a previous work we have
proposed the SQCLP (proximity-based qualified constraint logic programming)
scheme as a quite expressive extension of CLP with support for qualification
values and proximity relations as generalizations of uncertainty values and
similarity relations, respectively. In this paper we provide a transformation
technique for transforming SQCLP programs and goals into semantically
equivalent CLP programs and goals, and a practical Prolog-based implementation
of some particularly useful instances of the SQCLP scheme. We also illustrate,
by showing some simple-and working-examples, how the prototype can be
effectively used as a tool for solving problems where qualification values and
proximity relations play a key role. Intended use of SQCLP includes flexible
information retrieval applications.Comment: 49 pages, 5 figures, 1 table, preliminary version of an article of
the same title, published as Technical Report SIC-4-10, Universidad
Complutense, Departamento de Sistemas Inform\'aticos y Computaci\'on, Madrid,
Spai
Logic Negation with Spiking Neural P Systems
Nowadays, the success of neural networks as reasoning systems is doubtless.
Nonetheless, one of the drawbacks of such reasoning systems is that they work
as black-boxes and the acquired knowledge is not human readable. In this paper,
we present a new step in order to close the gap between connectionist and logic
based reasoning systems. We show that two of the most used inference rules for
obtaining negative information in rule based reasoning systems, the so-called
Closed World Assumption and Negation as Finite Failure can be characterized by
means of spiking neural P systems, a formal model of the third generation of
neural networks born in the framework of membrane computing.Comment: 25 pages, 1 figur
Analysis and test of the central-blue-spot infall hallmark
The infall of material onto a protostar, in the case of optically thick line
emission, produces an asymmetry in the blue- and red-wing line emission. For an
angularly resolved emission, this translates in a blue central spot in the
first-order moment (intensity weighted velocity) map. An analytical expression
for the first-order moment intensity as a function of the projected distance
was derived, for the cases of infinite and finite infall radius. The effect of
a finite angular resolution, which requires the numerical convolution with the
beam, was also studied. This method was applied to existing data of several
star-forming regions, namely G31.41+0.31 HMC, B335, and LDN 1287, obtaining
good fits to the first-order moment intensity maps, and deriving values of the
central masses onto which the infall is taking place (G31.41+0.31 HMC: 70-120
; B335: 0.1 ; Guitar Core of LDN 1287: 4.8 ). The
central-blue-spot infall hallmark appears to be a robust and reliable indicator
of infall.Comment: Accepted for publication in A&
Inner and outer star forming regions over the disks of spiral galaxies. I. Sample characterization
Context. The knowledge of abundance distributions is central to understanding
the formation and evolution of galaxies. Most of the relations employed for the
derivation of gas abundances have so far been derived from observations of
outer disk HII regions, despite the known differences between inner and outer
regions. Aims. Using integral field spectroscopy (IFS) observations we aim to
perform a systematic study and comparison of two inner and outer HII regions
samples. The spatial resolution of the IFS, the number of objects and the
homogeneity and coherence of the observations allow a complete characterization
of the main observational properties and differences of the regions. Methods.
We analyzed a sample of 725 inner HII regions and a sample of 671 outer HII
regions, all of them detected and extracted from the observations of a sample
of 263 nearby, isolated, spiral galaxies observed by the CALIFA survey.
Results. We find that inner HII regions show smaller equivalent widths, greater
extinction and luminosities, along with greater values of
[NII]{\lambda}6583/H{\alpha} and [OII]{\lambda}3727/[OIII]{\lambda}5007
emission-line ratios, indicating higher metallicites and lower ionization
parameters. Inner regions have also redder colors and higher photometric and
ionizing masses, although Mion/Mphot is slighty higher for the outer regions.
Conclusions. This work shows important observational differences between inner
and outer HII regions in star forming galaxies not previously studied in
detail. These differences indicate that inner regions have more evolved stellar
populations and are in a later evolution state with respect to outer regions,
which goes in line with the inside-out galaxy formation paradigm.Comment: 16 page
Deployment of Digital Video and Audio Over Electrical SCADA Networks
With the arrival of new hardware and software technologies,
supervisory control and data acquisition human-machine
interfaces (SCADA/HMI), usually text-based, can now benefit
from the advantages the inclusion of multimedia information
brings. However, due to the special requirements imposed by
such systems, integrating audio and video data into the SCADA
interfaces is not a trivial task. In this document we analyze those
special characteristics and propose solutions so this integration is
possible in power systems communication.Ministerio de Ciencia y TecnologÃa TIC2000-0367-P4-0
Kinetic study of the gas-phase reaction of atomic chlorine with a series of aldehydes
The reactions of Cl atoms with a series of unsaturated aldehydes have been investigated for the first time using a relative method. In order to obtain additional information for a qualitative structure versus reactivity discussion, we have also determined the rate coefficients for the reactions of atomic chlorine with their respective saturated aldehydes. These relative measurements were performed at room temperature and atmospheric pressure of air and N<sub>2</sub>, by using ethane, propene and 1-butene as reference compounds. The weighted average relative rate constants obtained, k<sub>Cl</sub>±2σ (in units of cm<sup>3</sup> molecule<sup>−1</sup> s<sup>−1</sup>) were: trans-2-pentenal (1.31±0.19)×10<sup>−10</sup>; trans-2-hexenal (1.92±0.22)×10<sup>−10</sup>; trans-2-heptenal (2.40±0.29)×10<sup>−10</sup>; n-pentanal (2.56±0.27)×10<sup>−10</sup>; n-hexanal (2.88±0.37)×10<sup>−10</sup>; n-heptanal (3.00±0.34)×10<sup>−10</sup>. <P style='line-height: 20px;'> Finally, results and atmospheric implications are discussed and compared with the reactivity with OH and NO<sub>3</sub> radicals
Tectonic implications of paleontologic dating of Cretaceous-Danian sections of Eastern Cuba
The sedimentary rocks intercalated in volcanic and metavolcanic sections of MayarÃ-Baracoa and Sierra del Purial Mountains (Eastern Cuba), yielded Cretaceous through Danian microfossils. In the Mayarà Mountains the Téneme Fm consists of basalts and hyaloclastites with minor intercalations of well-bedded foliated limestone and shaly limestone that in the type area contain a Turonian or early Coniacian planktonic foraminifera assemblage. In the Morel area (Moa-Baracoa massif), back-arc pillow basalts with ribbon cherts include a late Turonian or Coniacian limestone bed intercalated with interbedded organic-rich calcareous shales near the top. The upper part of the Coniacian (?)-Campanian Santo Domingo Fm crops out west of Moa and it consists of finegrained well-bedded volcaniclastic rocks with two intercalated lenses of coarse-grained impure biocalcirudites to biocalcarenites. These rocks yielded a mixed penecontemporaneous planktonic and benthonic microfossil assemblage attributed to the lower part of the late Campanian (Globotruncanita calcarata Zone). At Sierra del Purial, crystalline limestones embedded within the metavulcano-sedimentary RÃo Baracoa section (Purial metamorphic complex) yielded Campanian microfossils. The Maastrichtian Yaguaneque (=Cañas) limestones crop out extensively in both MayarÃ-Baracoa and Purial Mountains. All the formations previously mentioned unconformably overlie and tectonically intermingle with the late Maastrichtian-early Danian clastic rocks of the MÃcara and La Picota Fms. Our new dates demonstrate that in the Greater Antilles the PIA (Primitive Island Arc-tholeiite) recorded by the Téneme Fm would be Late Cretaceous in age in opposition to the Lower Cretaceous age proposed for the PIA basalts. The protolith of the Purial metamorphic complex is probably Maastrichtian-early Danian, but certainly Campanian and older in age. This fact suggests that the metamorphism that affected the Purial rocks took place probably in the late Maastrichtian and was coeval with the detachment, exhumation and emplacement of mafic-ultramafic thrust-sheet bodies. This event recorded in Eastern Cuba/Western Hispaniola and Guatemala might have been related to the insertion of thick oceanic ridges into the subduction zone
- …