1,030 research outputs found
A comparative study on bulk and nanoconfined water by time-resolved optical Kerr effect spectroscopy
The low frequency vibrational spectra of hydrated porous silica are
specifically sensitive to the hydrogen bond interactions and provides a wealth
of information on the structural and dynamical properties of the water
contained in the pores of the matrix. We investigate systematically this
spectral region of Vycor porous silica (pore size about 4 nm) for a series of
samples at different levels of hydration, from the dry matrix to completely
filled pores. The spectra are obtained as the Fourier transforms of
time-resolved heterodyne detected optical Kerr effect (HD- OKE) measurements.
The comparison of these spectra with that of bulk water allows us to extract
and analyze separately the spectral contributions of the first and second
hydration layers, as well as that of bulk-like inner water. We conclude that
the extra water entering the pores above 10 % water/silica weight ratio behaves
very similarly to bulk water. At lower levels of hydration, corresponding to
two complete superficial water layers or less, the H-bond bending and
stretching bands, characteristic of the tetrahedral coordination of water in
the bulk phase, progressively disappear: clearly in these conditions the H-bond
connectivity is very different from that of liquid water. A similar behavior is
observed for the structural relaxation times, measured from the decay of the
time-dependent HD-OKE signal. The value for the inner water is very similar to
that of the bulk liquid; that of the first two water layers is definitely
longer by about a factor 4. These findings should be carefully taken into
account when employing pore confinement to extend towards lower temperatures
the accessible temperature range of supercooled water
An Algorithm for Motion Parameter Direct Estimate
Motion estimation in image sequences is undoubtedly one of the most studied research fields, given that motion estimation is a basic tool for disparate applications, ranging from video coding to pattern recognition. In this paper a new methodology which, by minimizing a specific potential function, directly determines for each image pixel the motion parameters of the object the pixel belongs to is presented. The approach is based on Markov random fields modelling, acting on a first-order neighborhood of each point and on a simple motion model that accounts for rotations and translations. Experimental results both on synthetic (noiseless and noisy) and real world sequences have been carried out and they demonstrate the good performance of the adopted technique. Furthermore a quantitative and qualitative comparison with other well-known approaches has confirmed the goodness of the proposed methodology
A Bilingual Corpus of Inter-linked Events
This paper describes the creation of a bilingual corpus of inter-linked events for Italian and English. Linkage is accomplished through the Inter-Lingual Index (ILI) that links ItalWordNet with WordNet. The availability of this resource, on the one hand, enables contrastive analysis of the linguistic phenomena surrounding events in both languages, and on the other hand, can be used to perform multilingual temporal analysis of texts. In addition to describing the methodology for construction of the inter-linked corpus and the analysis of the data collected, we demonstrate that the ILI could potentially be used to bootstrap the creation of comparable corpora by exporting layers of annotation for words that have the same sense
Self-Aware Thermal Management for High-Performance Computing Processors
Editor's note: Thermal management in high-performance multicore platforms has become exceedingly complex due to variable workloads, thermal heterogeneity, and long, thermal transients. This article addresses these complexities by sophisticated analysis of noisy thermal sensor readings, dynamic learning to adapt to the peculiarities of the hardware and the applications, and a dynamic optimization strategy. - Axel Jantsch, TU Wien - Nikil Dutt, University of California at Irvine
Ontology Learning and Semantic Annotation: a Necessary Symbiosis
Semantic annotation of text requires the dynamic merging of linguistically structured information and a ?world model?, usually represented as a domain-specific ontology. On the other hand, the process of engineering a domain-ontology through semi-automatic ontology learning system requires the availability of a considerable amount of semantically annotated documents. Facing this bootstrapping paradox requires an incremental process of annotation-acquisition-annotation, whereby domain-specific knowledge is acquired from linguistically-annotated texts and then projected back onto texts for extra linguistic information to be annotated and further knowledge layers to be extracted. The presented methodology is a first step in the direction of a full ?virtuous? circle where the semantic annotation platform and the evolving ontology interact in symbiosis. As a case study we have chosen the semantic annotation of product catalogues. We propose a hybrid approach, combining pattern matching techniques to exploit the regular structure of product descriptions in catalogues, and Natural Language Processing techniques which are resorted to analyze natural language descriptions. The semantic annotation involves the access to the ontology, semi-automatically bootstrapped with an ontology learning tool from annotated collections of catalogues
Propuesta de un sistema ergonómico para mejorar las condiciones ergonómicas de los laboratorios de una universidad privada de la región Lambayeque
Este proyecto se basa en proponer un sistema ergonómico para poder mejorar las condiciones ergonómicas de los laboratorios de una universidad del departamento de Lambayeque, la cual mediante la medición de diferentes variables como iluminación, ruido y riesgos ergonómicos se realizará el diseño de este sistema. Para el confort lumínico se tuvo una eficiencia del 0% y para el confort acústico una eficiencia del 0% y los riesgos ergonómicos mediante la metodología REBA dio una puntuación de 9 con un nivel alto de riesgo lo cual es ocasionado por el mobiliario y su mala distribución. Como resultados de la propuesta en el confort lumínico se mejoró la eficiencia en un 100%, para el confort acústico de la misma manera se mejoró la eficiencia en un 100% y para los riesgos ergonómicos se cambió el mobiliario y su distribución evaluando nuevamente mediante REBA y teniendo una nueva puntuación de 3 con un nivel de riesgo bajo. Esta implementación evitaría pagar a la universidad una multa de S/. 5 600 000 ahorrando por cada unidad de inversión S/. 59,30 siendo sumamente rentable para la universidad
Esca symptoms appearance in Vitis vinifera L.: influence of climate, pedo-climatic conditions and rootstock/cultivar combination
This study investigated the appearance of esca
symptoms in relation to environmental factors and
the rootstock/cultivar combination in an experimental
setting between 2004 and 2009. Among the common
genotypes showing susceptibility to the esca disease,
four cultivars were considered: ‘Cabernet Sauvignon’,
‘Sangiovese’, ‘Trebbiano Toscano’ and ‘Chardonnay’.
These cultivars were studied own-rooted and in combination
with two rootstocks: Kober 5BB and 1103
Paulsen. The difference in susceptibility of cultivars to
esca appeared negatively related to the graft. No clear
relation was found between esca appearance and environmental
factors. Moreover, an unexpected discordance
between esca incidence percentage and mortality
rate was observed
UFRA: a UIMA-based Approach to Federated Language Resource Architecture
In this paper we address the issue of developing an interoperable infrastructure for language resources and technologies. In our approach, called UFRA, we extend the Federate Database Architecture System adding typical functionalities caming from UIMA. In this way, we capitalize the advantages of a federated architecture, such as autonomy, heterogeneity and distribution of components, monitored by a central authority responsible for checking both the integration of components and user rights on performing different tasks. We use the UIMA approach to manage and define one common front-end, enabling users and clients to query, retrieve and use language resources and technologies. The purpose of this paper is to show how UIMA leads from a Federated Database Architecture to a Federated Resource Architecture, adding to a registry of available components both static resources such as lexicons and corpora and dynamic ones such as tools and general purpose language technologies. At the end of the paper, we present a case-study that adopts this framework to integrate the SIMPLE lexicon and TIMEML annotation guidelines to tag natural language texts
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