7,624 research outputs found
Boosting Handwriting Text Recognition in Small Databases with Transfer Learning
In this paper we deal with the offline handwriting text recognition (HTR)
problem with reduced training datasets. Recent HTR solutions based on
artificial neural networks exhibit remarkable solutions in referenced
databases. These deep learning neural networks are composed of both
convolutional (CNN) and long short-term memory recurrent units (LSTM). In
addition, connectionist temporal classification (CTC) is the key to avoid
segmentation at character level, greatly facilitating the labeling task. One of
the main drawbacks of the CNNLSTM-CTC (CLC) solutions is that they need a
considerable part of the text to be transcribed for every type of calligraphy,
typically in the order of a few thousands of lines. Furthermore, in some
scenarios the text to transcribe is not that long, e.g. in the Washington
database. The CLC typically overfits for this reduced number of training
samples. Our proposal is based on the transfer learning (TL) from the
parameters learned with a bigger database. We first investigate, for a reduced
and fixed number of training samples, 350 lines, how the learning from a large
database, the IAM, can be transferred to the learning of the CLC of a reduced
database, Washington. We focus on which layers of the network could be not
re-trained. We conclude that the best solution is to re-train the whole CLC
parameters initialized to the values obtained after the training of the CLC
from the larger database. We also investigate results when the training size is
further reduced. The differences in the CER are more remarkable when training
with just 350 lines, a CER of 3.3% is achieved with TL while we have a CER of
18.2% when training from scratch. As a byproduct, the learning times are quite
reduced. Similar good results are obtained from the Parzival database when
trained with this reduced number of lines and this new approach.Comment: ICFHR 2018 Conferenc
Magnetized, Relativistic Jets
Extragalactic relativistic jets are composed by charged particles and
magnetic fields, as inferred from the synchrotron emission that we receive from
them. The Larmor radii of the particles propagating along the magnetic field
are much smaller than the scales of the problem, providing the necessary
coherence to the system to treat is as a flow. We can thus study them using
relativistic magnetohydrodynamics. As a first step, we have studied the
structure of steady-state configurations of jets by using numerical
simulations. We have used a helical field configuration and have changed
different relevant parameters that control the way in which the energy flux is
distributed in jets (namely, the proportion of the energy flux carried by
internal, kinetic or magnetic energy). Our results show significant differences
among the different kinds of jets. Finally, we also report on results based on
synthetic maps of our simulated jets.Comment: Submitted for publication in Proceedings of Science, as contribution
to the proceedings of the XII Multifrequency Behaviour of High Energy Cosmic
Sources Workshop, held in Palermo, 12-17 June 201
Validity and Reliability of an Inertial Device for Measuring Dynamic Weight-Bearing Ankle Dorsiflexion
A decrease in ankle dorsiflexion causes changes in biomechanics, and different instruments have been used for ankle dorsiflexion testing under static conditions. Consequently, the industry of inertial sensors has developed easy-to-use devices, which measure dynamic ankle dorsiflexion and provide additional parameters such as velocity, acceleration, or movement deviation. Therefore, the aims of this study were to analyze the concurrent validity and test-retest reliability of an inertial device for measuring dynamic weight-bearing ankle dorsiflexion. Sixteen participants were tested using an inertial device (WIMU) and a digital inclinometer. Ankle dorsiflexion from left and right ankle repetitions was used for validity analysis, whereas test-retest reliability was analyzed by comparing measurements from the first and second days. The standard error of the measurement (SEM) between the instruments was very low for both ankle measurements (SEM 0.05) even though a significant systematic bias (~1.77°) was found for the right ankle (d = 0.79). R2 was very close to 1 in the left and right ankles (R2 = 0.85â0.89) as well as the intraclass correlation coefficient (ICC > 0.95). Test-retest reliability analysis showed that systematic bias was below 1° for both instruments, even though a systematic bias (~1.50°) with small effect size was found in the right ankle (d = 0.49) with WIMU. The ICC was very close to 1 and the coefficient of variation (CV) was lower than 4% in both instruments. Thus, WIMU is a valid and reliable inertial device for measuring dynamic weight-bearing ankle dorsiflexion
Ownership Structure of Cooperatives as an Environmental Buffer.
In this paper, we propose that the ownership structure in the cooperative form acts as an environmental buffer. It is a mechanism to obtain stronger linkages with suppliers by internalizing them, and in this way, obtaining fundamental resources. Using this strategy, the cooperative form can isolate itself from adverse environments and from competition from other organizational forms. Although cooperatives have higher survival probability in any economic context, in rival ideological environments they have less support than other organizational forms. To test these ideas, we have chosen data from the Spanish olive oil milling industry for 1944â98. During this period, Spain changed from a dictatorial to a democratic regime and from a self-subsistence economy in the post civil-war period to a broad liberal international economy. The results show that, whereas other organizational forms are affected by economic and ideological influences, the cooperative form isolates itself by changing the competition level.
Relationship between legitimation, competition and organizational death: current state of the art.
There is agreement among ecology researchers that the concepts of legitimation and competition are partly responsible for organizational selection. Finding adequate measures to represent these concepts, however, has been elusive and has been the main obstacle to the development of this stream of investigation. On the basis of the germinal density dependence model, we identify two lines of research, which have generated seven distinct models. This survey shows that there has been a general tendency to use only three variables to measure legitimation and competition, which are often measured together. However, we argue that fruitful results have emerged when efforts have been made to separate both concepts and that there is some potential in using new measures (mass or concentration) which have so far only found limited application in the field of population demography. These findings, together with the inconclusive results of this stream of research, allow us to identify the existing gaps in the literature and comment on directions for future research.SociologĂa de la organizaciĂłn; Cambio organizativo;
Rapid asymmetric transfer hydroformylation (ATHF) of disubstituted alkenes using paraformaldehyde as a syngas surrogate
The authors thank Dr. Reddys (UK) and the Royal Society for an Industry Fellowship in the early stage of this work (2012â2014), and the EPSRC for funding (EP/M003868/1).As an alternative to conventional asymmetric hydroformylation (AHF), Asymmetric Transfer Hydroformylation (ATHF) using formaldehyde as a surrogate for syngas is reported. A catalyst derived from commercially available [Rh(acac)(CO)2] and Ph-BPE stands out in terms of both activity and enantioselectivity. Remarkably, not only are high selectivities achievable, the reactions are very simple to carry out, and can give higher enantioselectivity (up to 96% e.e.) and/or turnover frequencies than those that are achievable using the same catalyst (or other leading catalysts) using typical conditions for AHF.Publisher PDFPeer reviewe
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