1,387 research outputs found
Multitask learning without label correspondences
We propose an algorithm to perform multitask learning where each task has potentially distinct label sets and label correspondences are not readily available. This is in contrast with existing methods which either assume that the label sets shared by different tasks are the same or that there exists a label mapping oracle. Our method directly maximizes the mutual information among the labels, and we show that the resulting objective function can be efficiently optimized using existing algorithms. Our proposed approach has a direct application for data integration with different label spaces for the purpose of classification, such as integrating Yahoo! and DMOZ web directories
M\"obius and twisted graphene nanoribbons: stability, geometry and electronic properties
Results of classical force field geometry optimizations for twisted graphene
nanoribbons with a number of twists varying from 0 to 7 (the case =1
corresponds to a half-twist M\"obius nanoribbon) are presented in this work.
Their structural stability was investigated using the Brenner reactive force
field. The best classical molecular geometries were used as input for
semiempirical calculations, from which the electronic properties (energy
levels, HOMO, LUMO orbitals) were computed for each structure. CI wavefunctions
were also calculated in the complete active space framework taking into account
eigenstates from HOMO-4 to LUMO+4, as well as the oscillator strengths
corresponding to the first optical transitions in the UV-VIS range. The lowest
energy molecules were found less symmetric than initial configurations, and the
HOMO-LUMO energy gaps are larger than the value found for the nanographene used
to build them due to electronic localization effects created by the twisting. A
high number of twists leads to a sharp increase of the HOMO LUMO
transition energy. We suggest that some twisted nanoribbons could form crystals
stabilized by dipolar interactions
Salvage Flexor Hallucis Longus Transfer for a Failed Achilles Repair: Endoscopic Technique
Flexor hallucis longus (FHL) transfer is a well-established treatment option in failed Achilles tendon (AT) repair and has been routinely performed as an open procedure. We detail the surgical steps needed to perform an arthroscopic transfer of the FHL for a chronic AT rupture. The FHL tendon is harvested as it enters in its tunnel beneath the sustentaculum tali; a tunnel is then drilled in the calcaneus as near to the AT footprint as possible. By use of a suture-passing device, the free end of the FHL is advanced to the plantar aspect of the foot. After adequate tension is applied to the construct, the tendon is fixed in place with an interference screw in an inside-out fashion. This minimally invasive approach is a safe and valid alternative to classic open procedures with the obvious advantages of preserving the soft-tissue envelope and using a biologically intact tendon
A method to incorporate uncertainty in the classification of remote sensing images
The aim of this paper is to investigate if the incorporation of the uncertainty
associated with the classification of surface elements into the classification of
landscape units (LUs) increases the results accuracy. To this end, a hybrid classification
method is developed, including uncertainty information in the classification
of very high spatial resolution multi-spectral satellite images, to obtain a map
of LUs. The developed classification methodology includes the following steps: (1)
a pixel-based hard classification with a probabilistic Bayesian classifier; (2) computation
of the posterior probabilities and quantification of the classification
uncertainty using an uncertainty measure; (3) image segmentation and (4) object
classification based on decision rules. The classification of the resulting objects into
LUs is performed considering a set of decision rules that incorporate the pixelbased
classification uncertainty. The proposed methodology was tested on the
classification of an IKONOS satellite image. The accuracy of the classification was
computed using an error matrix. The comparison between the results obtained
with the proposed approach and those obtained without considering the classification
uncertainty revealed a 12% increase in the overall accuracy. This shows that
the information about uncertainty can be valuable when making decisions and can
actually increase the accuracy of the classification results.info:eu-repo/semantics/publishedVersio
Assessment of the state of conservation of buildings through roof mapping using very high spatial resolution images
The assessment of the state of conservation of buildings is extremely important in urban rehabilitation. In
the case of historical towns or city centres, the pathological characterization using traditional methods is
a laborious and time consuming procedure. This study aims to show that Very High Spatial Resolution
(VHSR) multispectral images can be used to obtain information regarding the state of conservation of
roofs where, usually, building degradation starts. The study was performed with multispectral aerial
images with a spatial resolution of 0.5 m. To extract the required information, a hybrid classification
method was developed, that integrates pixel and object based classification methods, as well as information regarding the classification uncertainty. The proposed method was tested on the classification of the historical city centre of Coimbra, in Portugal, that includes over than 800 buildings. The results were then validated with the data obtained from a study conducted during 2 years by a nine element team from the University of Coimbra, using traditional methods. The study performed achieved a global classification accuracy of 78%, which proves that the state of conservation of roofs can be obtained from VHSR multispectralimages using the described methodology with a fairly good accuracy.info:eu-repo/semantics/publishedVersio
Desenvolvimento inicial de espécies florestais em reflorestamento na região metropolitana do Rio de Janeiro.
Biofuel production from phytoremediation derived sunflower biomass
info:eu-repo/semantics/publishedVersio
Techno-economic assessment of a Synechocystis based biorefinery through process optimization
UID/EQU/00511/2019 "LEPABE-2-ECOINNOVATION"-NORTE-01-0145-FEDER-000005.Similar to oil, biological origin feedstock can be converted into a number of products allowing to recover the maximum value from the raw biological material, within what is nowadays called a biorefinery. Among other biological materials, microalgae are a very interesting biomass due to the high economic value of certain cellular components, such as carotenoids and polyunsaturated fatty acids. In this project, a genetically modified cyanobacteria, that produces ethanol as an extracellular product, was used as the basis of this study. In order to assess the optimal configuration of the biorefinery, different scenarios were designed, each one with different sequences of unit operations, equipment and products. With the design stage completed, an economic analysis was performed to choose the 2 scenarios with the best economic performance.publishersversionpublishe
Right Atrial Thrombus: a Rare Presentation of Plasminogen Activator Inhibitor Deficiency
A presença de trombos móveis na aurícula direita são fenómenos raros, mas associados
a uma elevada mortalidade. Apesar de a ecocardiografia ter permitido avanços no seu
diagnóstico, a sua abordagem continua a ser motivo de debate. Neste artigo apresentamos o
caso de uma doente do sexo feminino, de 24 anos, com antecedentes de tabagismo, obesidade e sob terapêutica anovulatória que recorre ao serviço de urgência por cansaço fácil e tosse com expetoração hemoptoica. O ecocardiograma transtorácico revelou massa, móvel, multilobulada de grandes dimensões na aurícula direita, condicionando abertura da válvula tricúspide.
Perante episódios recorrentes de embolia pulmonar, foi submetida a cirurgia cardíaca com exérese da massa, sendo o resultado anatomopatológico compatível com trombo organizado com calcificação. O estudo genético revelou homozigotia para a variante alélica PAI-1:-675G >A(4G/4G) do inibidor do ativador do plasminogénio e heterozigotia para a variante alélica MTHFR 1298 A/C da 5,10-metilenotetrahidrofolato redutase
M\"obius and twisted graphene nanoribbons: stability, geometry and electronic properties
Results of classical force field geometry optimizations for twisted graphene
nanoribbons with a number of twists varying from 0 to 7 (the case =1
corresponds to a half-twist M\"obius nanoribbon) are presented in this work.
Their structural stability was investigated using the Brenner reactive force
field. The best classical molecular geometries were used as input for
semiempirical calculations, from which the electronic properties (energy
levels, HOMO, LUMO orbitals) were computed for each structure. CI wavefunctions
were also calculated in the complete active space framework taking into account
eigenstates from HOMO-4 to LUMO+4, as well as the oscillator strengths
corresponding to the first optical transitions in the UV-VIS range. The lowest
energy molecules were found less symmetric than initial configurations, and the
HOMO-LUMO energy gaps are larger than the value found for the nanographene used
to build them due to electronic localization effects created by the twisting. A
high number of twists leads to a sharp increase of the HOMO LUMO
transition energy. We suggest that some twisted nanoribbons could form crystals
stabilized by dipolar interactions
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