2,811,164 research outputs found
The ALVIS Format for Linguistically Annotated Documents
The paper describes the ALVIS annotation format designed for the indexing of
large collections of documents in topic-specific search engines. This paper is
exemplified on the biological domain and on MedLine abstracts, as developing a
specialized search engine for biologists is one of the ALVIS case studies. The
ALVIS principle for linguistic annotations is based on existing works and
standard propositions. We made the choice of stand-off annotations rather than
inserted mark-up. Annotations are encoded as XML elements which form the
linguistic subsection of the document record
Hardening communication ports for survival in electrical overstress environments
Greater attention is being focused on the protection of data I/O ports since both experience and lab tests have shown that components at these locations are extremely vulnerable to electrical overstress (EOS) in the form of transient voltages. Lightning and electrostatic discharge (ESD) are the major contributors to these failures; however, these losses can be prevented. Hardening against transient voltages at both the board level and system level has a proven record of improving reliability by orders of magnitude. The EOS threats, typical failure modes, and transient voltage mitigation techniques are reviewed. Case histories are also reviewed
Minimum requirements for feedback enhanced force sensing
The problem of estimating an unknown force driving a linear oscillator is
revisited. When using linear measurement, feedback is often cited as a
mechanism to enhance bandwidth or sensitivity. We show that as long as the
oscillator dynamics are known, there exists a real-time estimation strategy
that reproduces the same measurement record as any arbitrary feedback protocol.
Consequently some form of nonlinearity is required to gain any advantage beyond
estimation alone. This result holds true in both quantum and classical systems,
with non-stationary forces and feedback, and in the general case of
non-Gaussian and correlated noise. Recently, feedback enhanced incoherent force
sensing has been demonstrated [Nat. Nano. \textbf{7}, 509 (2012)], with the
enhancement attributed to a feedback induced modification of the mechanical
susceptibility. As a proof-of-principle we experimentally reproduce this result
through straightforward filtering.Comment: 5 pages + 2 pages of Supplementary Informatio
Husserl on Hallucination: A Conjunctive Reading
Several commentators have recently attributed conflicting accounts of the relation between veridical perceptual experience and hallucination to Husserl. Some say he is a proponent of the conjunctive view that the two kinds of experience are fundamentally the same. Others deny this and purport to find in Husserl distinct and non-overlapping accounts of their fundamental natures, thus committing him to a disjunctive view. My goal is to set the record straight. Having briefly laid out the problem under discussion and the terms of the debate, I then review the proposals that have been advanced, disposing of some and marking others for further consideration. A.D. Smith’s disjunctive reading is among the latter. I discuss it at length, arguing that Smith fails to show that Husserl’s views on perceptual experience entail a form of disjunctivism. Following that critical discussion, I present a case for a conjunctive reading of Husserl’s account of perceptual experience
On the survivability and detectability of terrestrial meteorites on the moon
Materials blasted into space from the surface of early Earth may preserve a unique record of our planet's early surface environment. Armstrong et al. (2002) pointed out that such materials, in the form of terrestrial meteorites, may exist on the Moon and be of considerable astrobiological interest if biomarkers from early Earth are preserved within them. Here, we report results obtained via the AUTODYN hydrocode to calculate the peak pressures within terrestrial meteorites on the lunar surface to assess their likelihood of surviving the impact. Our results confirm the order-of-magnitude estimates of Armstrong et al. (2002) that substantial survivability is to be expected, especially in the case of relatively low velocity (ca. 2.5 km/s) or oblique (≤45°) impacts, or both. We outline possible mechanisms for locating such materials on the Moon and conclude that searching for them would be a scientifically valuable activity for future lunar exploration
Hitsville UK: punk in the faraway towns
This was an exhibition of UK punk rock record sleeve design across the period 1976-1984, and consisted of a wide range of record sleeves grouped by punk and post punk sub-genres, and a large format exhibition timeline mapping the chronology and geography of the graphic evolution of punk within this timeframe, using seven inch single sleeves as a representative case study for analysis. This was accompanied by a range of interactive and sound installations allowing users to view the production details of each sleeve and to hear the music on the records.
The research consisted of a detailed analysis of ‘quintessentially punk artefacts’, the seven-inch ‘picture’ record sleeves associated with UK Punk. New perspectives on their production and their graphic characteristics including any recurring visual tropes or pictorial devices and the use of a DIY aesthetic were created.
The period covered was c.1976-1984. Two important aspects of the research methodology were, firstly, to consider the graphic design of the record sleeves through the prism of the complex sub-cultural codes that were characteristic of UK Punk at this period and, secondly, to view these graphic artefacts as indissoluble from the UK Punk’s musical language. An additional feature of the research was the mapping of the diaspora of UK Punk form London, Manchester and other large cities to ‘the faraway towns’ by means of a visual matrix that demonstrated a widening geographic spread of seven-inch single production during much of period.
The exhibitions which were slightly different in each venue, celebrated the wide range of graphic approaches adopted and redressed the balance of recent punk accounts which focus on the short-lived activities of UK Punk’s early years.
Together with the visual matrix and real-size reproductions of a wide range of graphic material, the research resulted in an exhibition catalogue package that included three reversible posters, and an interactive web-based resource which links the seven-inch sleeve to its key musical track
Preserving the impossible: conservation of soft-sediment hominin footprint sites and strategies for three-dimensional digital data capture.
Human footprints provide some of the most publically emotive and tangible evidence of our ancestors. To the scientific community they provide evidence of stature, presence, behaviour and in the case of early hominins potential evidence with respect to the evolution of gait. While rare in the geological record the number of footprint sites has increased in recent years along with the analytical tools available for their study. Many of these sites are at risk from rapid erosion, including the Ileret footprints in northern Kenya which are second only in age to those at Laetoli (Tanzania). Unlithified, soft-sediment footprint sites such these pose a significant geoconservation challenge. In the first part of this paper conservation and preservation options are explored leading to the conclusion that to 'record and digitally rescue' provides the only viable approach. Key to such strategies is the increasing availability of three-dimensional data capture either via optical laser scanning and/or digital photogrammetry. Within the discipline there is a developing schism between those that favour one approach over the other and a requirement from geoconservationists and the scientific community for some form of objective appraisal of these alternatives is necessary. Consequently in the second part of this paper we evaluate these alternative approaches and the role they can play in a 'record and digitally rescue' conservation strategy. Using modern footprint data, digital models created via optical laser scanning are compared to those generated by state-of-the-art photogrammetry. Both methods give comparable although subtly different results. This data is evaluated alongside a review of field deployment issues to provide guidance to the community with respect to the factors which need to be considered in digital conservation of human/hominin footprints
Identifying Biomagnetic Sources in the Brain by the Maximum Entropy Approach
Magnetoencephalographic (MEG) measurements record magnetic fields generated
from neurons while information is being processed in the brain. The inverse
problem of identifying sources of biomagnetic fields and deducing their
intensities from MEG measurements is ill-posed when the number of field
detectors is far less than the number of sources. This problem is less severe
if there is already a reasonable prior knowledge in the form of a distribution
in the intensity of source activation. In this case the problem of identifying
and deducing source intensities may be transformed to one of using the MEG data
to update a prior distribution to a posterior distribution. Here we report on
some work done using the maximum entropy method (ME) as an updating tool.
Specifically, we propose an implementation of the ME method in cases when the
prior contain almost no knowledge of source activation. Two examples are
studied, in which part of motor cortex is activated with uniform and varying
intensities, respectively.Comment: 8 pages, 8 figures. Presented at 25th International Workshop on
Bayesian Inference and Maximum Entropy Methods in Science and Engineering,
San Jose, CA, USA Aug 7-12, 200
Violation of the Wiedemann-Franz law in clean graphene layers
The Wiedemann-Franz law, connecting the electronic thermal conductivity to
the electrical conductivity of a disordered metal, is generally found to be
well satisfied even when electron-electron (e-e) interactions are strong. In
ultra-clean conductors, however, large deviations from the standard form of the
law are expected, due to the fact that e-e interactions affect the two
conductivities in radically different ways. Thus, the standard Wiedemann-Franz
ratio between the thermal and the electric conductivity is reduced by a factor
, where is the momentum relaxation
rate, and is the relaxation time of the thermal
current due to e-e collisions. Here we study the density and temperature
dependence of in the important case of doped, clean
single layers of graphene, which exhibit record-high thermal conductivities. We
show that at low temperature is of the
quasiparticle decay rate. We also show that the many-body renormalization of
the thermal Drude weight coincides with that of the Fermi velocity.Comment: 6 pages, 5 appendices (13 pages
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