53,973 research outputs found
A Formal Framework for Linguistic Annotation
`Linguistic annotation' covers any descriptive or analytic notations applied
to raw language data. The basic data may be in the form of time functions --
audio, video and/or physiological recordings -- or it may be textual. The added
notations may include transcriptions of all sorts (from phonetic features to
discourse structures), part-of-speech and sense tagging, syntactic analysis,
`named entity' identification, co-reference annotation, and so on. While there
are several ongoing efforts to provide formats and tools for such annotations
and to publish annotated linguistic databases, the lack of widely accepted
standards is becoming a critical problem. Proposed standards, to the extent
they exist, have focussed on file formats. This paper focuses instead on the
logical structure of linguistic annotations. We survey a wide variety of
existing annotation formats and demonstrate a common conceptual core, the
annotation graph. This provides a formal framework for constructing,
maintaining and searching linguistic annotations, while remaining consistent
with many alternative data structures and file formats.Comment: 49 page
Online Context-based Object Recognition for Mobile Robots
This work proposes a robotic object recognition
system that takes advantage of the contextual information latent
in human-like environments in an online fashion. To fully leverage
context, it is needed perceptual information from (at least) a
portion of the scene containing the objects of interest, which could
not be entirely covered by just an one-shot sensor observation.
Information from a larger portion of the scenario could still
be considered by progressively registering observations, but this
approach experiences difficulties under some circumstances, e.g.
limited and heavily demanded computational resources, dynamic
environments, etc. Instead of this, the proposed recognition
system relies on an anchoring process for the fast registration
and propagation of objects’ features and locations beyond the
current sensor frustum. In this way, the system builds a graphbased
world model containing the objects in the scenario (both
in the current and previously perceived shots), which is exploited
by a Probabilistic Graphical Model (PGM) in order to leverage
contextual information during recognition. We also propose a
novel way to include the outcome of local object recognition
methods in the PGM, which results in a decrease in the usually
high CRF learning complexity. A demonstration of our proposal
has been conducted employing a dataset captured by a mobile
robot from restaurant-like settings, showing promising results.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Distributed coding of endoscopic video
Triggered by the challenging prerequisites of wireless capsule endoscopic video technology, this paper presents a novel distributed video coding (DVC) scheme, which employs an original hash-based side-information creation method at the decoder. In contrast to existing DVC schemes, the proposed codec generates high quality side-information at the decoder, even under the strenuous motion conditions encountered in endoscopic video. Performance evaluation using broad endoscopic video material shows that the proposed approach brings notable and consistent compression gains over various state-of-the-art video codecs at the additional benefit of vastly reduced encoding complexity
A unified accretion-ejection paradigm for Black Hole X-ray Binaries
We present a new picture for the central regions of Black Hole X-ray
Binaries. In our view, these central regions have a multi-flow configuration
which consists in (1) an outer standard accretion disc down to a transition
radius r_J, (2) an inner magnetized accretion disc below r_J driving (3) a non
relativistic self-collimated electron-proton jet surrounding, when adequate
conditions for pair creation are met, (4) a ultra relativistic
electron-positron beam. This accretion-ejection paradigm provides a simple
explanation to the canonical spectral states by varying the transition radius
r_J and disc accretion rate independently. Large values of r_J correspond to
the Quiescent state for low and the Hard state for larger .
These states are characterized by the presence of a steady electron-proton MHD
jet emitted by the disc below r_J. The hard X-ray component is expected to form
at the jet basis. When r_j becomes smaller than the marginally stable orbit
r_i, the whole disc resembles a standard accretion disc, characteristic of the
Soft state. Intermediate states correspond to situations where r_J ~ r_i. At
large , an unsteady pair cascade process is triggered within the jet
axis, giving birth to ejection of relativistic pair blobs. This would
correspond to the luminous intermediate state, with its associated superluminal
motions. The variation of r_J independently of is a necessary
ingredient in this picture, arising from the presence of a large scale vertical
magnetic field threading the disc.Comment: 15 pages, 2 figures. Accepted by A&A main journa
Toward a Unified Timestamp with explicit precision
Demographic and health surveillance (DS) systems monitor and document individual- and group-level processes in well-defined populations over long periods of time. The resulting data are complex and inherently temporal. Established methods of storing and manipulating temporal data are unable to adequately address the challenges posed by these data. Building on existing standards, a temporal framework and notation are presented that are able to faithfully record all of the time-related information (or partial lack thereof) produced by surveillance systems. The Unified Timestamp isolates all of the inherent complexity of temporal data into a single data type and provides the foundation on which a Unified Timestamp class can be built. The Unified Timestamp accommodates both point- and interval-based time measures with arbitrary precision, including temporal sets. Arbitrary granularities and calendars are supported, and the Unified Timestamp is hierarchically organized, allowing it to represent an unlimited array of temporal entities.demographic surveillance, standardization, temporal databases, temporal integrity, timestamp, valid time
Can ecosystem properties be fully translated into service values? an economic valuation of aquatic plant services
Ecological Applications 21. 5 (2011): 3083-3103 copyright by the Ecological Society of AmericaWe carried out an integrated analysis of ecosystem services in the Doñana social-ecological system (southwestern Spain), from the providers (different aquatic plant functional groups) to the beneficiaries (different stakeholders living in or visiting the area). We explored the ecosystem services supplied by aquatic plants by linking these services to different plant functional traits, identifying relevant ecosystem services and then working our way backward to ecosystem properties and the functional traits underpinning them. We started from 15 ecosystem services associated with aquatic systems (freshwater marshes, salt marshes, ponds on aeolian sheets, temporal coastal ponds, and estuaries) and related them to plant traits (directly or indirectly through intermediate ecosystem properties). We gathered information from the literature on the functional traits of 144 plants occurring in the aquatic ecosystems of Doñana. We analyzed the speciesĂ—trait matrix with multivariate classification and ordination techniques and obtained seven functional groups with different potentials for delivering ecosystem services. A survey was then administered to 477 stakeholders to analyze, through the use of a contingent valuation exercise, how the ecosystem services provided by the different functional groups were valued. We identified connections between individual plant traits, ecosystem processes, and ecosystem services, but a mismatch appeared between the functional groups and the economic values placed on them by the beneficiaries. We found that contingent valuation applied to ecosystem services tended to ignore the ecosystem properties and biodiversity underpinning them. Our results cast doubts over the suitability of the economic valuation framework of ecosystem services to capture the full value of biodiversity and ecosystems to peopleThis research was partially supported by a grant from the Madrid Regional Government of Education, which was co-funded by the Social European Fund (F.S.E.), the Spanish Ministry of Education and Science (Project CGL2006- 14121/BOS), and the Spanish Ministry of the Environment and Rural and Marine Affairs through project 018/2009. S. DĂaz
acknowledges support from FONCyT and CONICET (Argentina)
and IAI (CRN 2015, supported by US NSF GEO-
0452325
Interfaces with a single growth inhomogeneity and anchored boundaries
The dynamics of a one dimensional growth model involving attachment and
detachment of particles is studied in the presence of a localized growth
inhomogeneity along with anchored boundary conditions. At large times, the
latter enforce an equilibrium stationary regime which allows for an exact
calculation of roughening exponents. The stochastic evolution is related to a
spin Hamiltonian whose spectrum gap embodies the dynamic scaling exponent of
late stages. For vanishing gaps the interface can exhibit a slow morphological
transition followed by a change of scaling regimes which are studied
numerically. Instead, a faceting dynamics arises for gapful situations.Comment: REVTeX, 11 pages, 9 Postscript figure
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