1,892 research outputs found
Arabic Spelling Correction using Supervised Learning
In this work, we address the problem of spelling correction in the Arabic
language utilizing the new corpus provided by QALB (Qatar Arabic Language Bank)
project which is an annotated corpus of sentences with errors and their
corrections. The corpus contains edit, add before, split, merge, add after,
move and other error types. We are concerned with the first four error types as
they contribute more than 90% of the spelling errors in the corpus. The
proposed system has many models to address each error type on its own and then
integrating all the models to provide an efficient and robust system that
achieves an overall recall of 0.59, precision of 0.58 and F1 score of 0.58
including all the error types on the development set. Our system participated
in the QALB 2014 shared task "Automatic Arabic Error Correction" and achieved
an F1 score of 0.6, earning the sixth place out of nine participants.Comment: System description paper that is submitted in the EMNLP 2014
conference shared task "Automatic Arabic Error Correction" (Mohit et al.,
2014) in the Arabic NLP workshop. 6 page
A New Look at MIMO Capacity in the Millimeter Wave
In this paper, we present a new theoretical discovery that the multiple-input
and multiple-output (MIMO) capacity can be influenced by atmosphere molecules.
In more detail, some common atmosphere molecules, such as Oxygen and water, can
absorb and re-radiate energy in their natural resonance frequencies, such as
60GHz, 120GHz, and 180GHz, which belong to the millimeter wave (mmWave)
spectrum. Such phenomenon can provide equivalent non-line-of-sight (NLoS) paths
in an environment that lacks scatterers, and thus greatly improve the spatial
multiplexing and diversity of a MIMO system. This kind of performance
improvement is particularly useful for most mmWave communications that heavily
rely on line-of-sight (LoS) transmissions. To sum up, our study concludes that
since the molecular re-radiation happens at certain mmWave frequency bands, the
MIMO capacity becomes highly frequency selective and enjoys a considerable
boosting at those mmWave frequency bands. The impact of our new discovery is
significant, which fundamentally changes our understanding on the relationship
between the MIMO capacity and the frequency spectrum. In particular, our
results predict that several mmWave bands can serve as valuable spectrum
windows for high-efficiency MIMO communications, which in turn may shift the
paradigm of research, standardization, and implementation in the field of
mmWave communications.Comment: arXiv admin note: text overlap with arXiv:1710.0903
Characterizing the Role of CpsA in Mycobacterial Pathogenesis
Mycobacterium tuberculosis infects one-third of the world’s population and causes an estimated 2 million deaths per year, more than any other single bacterial pathogen. The inadequacies of existing tuberculosis therapies demand the discovery of novel agents to treat M. tuberculosis infection, which requires mechanistic insight into the pathways involved in mycobacterial pathogenesis. We identified an unanticipated role of the M. tuberculosis protein CpsA in preventing phago-lysosome fusion by host macrophages, resulting in enhanced intracellular survival of bacteria within the host. Strains of M. tuberculosis lacking cpsA are severely attenuated in both macrophage and mouse models, thus establishing CpsA as a crucial virulence factor in M. tuberculosis infection. CpsA is a yet uncharacterized secreted protein, belonging to the LytR–CpsA–PsR family, that we found interacts with host proteins NDP52 and TAX1BP1, which are involved in intracellular trafficking. Here, we sought to (1) examine whether CpsA is sufficient to confer virulence to Mycobacterium smegmatis, a rapidly-growing, non-pathogenic bacterium that does not contain CpsA naturally, and (2) determine which domains of CpsA are required for interacting with host proteins and contributing to virulence. We infected RAW264.7 macrophages with M. smegmatis expressing M. tuberculosis cpsA and vector control and scored for intracellular survival of bacteria. Our preliminary data suggest that CpsA confers enhanced intracellular survival to M. smegmatis, as compared to vector control. To characterize CpsA interaction with TAX1BP1 and NDP52, we generated deletion constructs of CpsA and, using a yeast two-hybrid system, investigated which domains of the CpsA protein are required for the interaction with these host proteins. Follow up work involves determining which domains are also required for virulence. Overall, we hope that by studying the molecular mechanisms by which M. tuberculosis CpsA sabotages cellular functions, we can better understand both the host immunity and mycobacterial pathogenesis
Chinese Medicine in Uganda: Health, Wealth, and Globalization
From the Washington University Senior Honors Thesis Abstracts (WUSHTA), 2017. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Lindsey Paunovich, Editor; Helen Human, Programs Manager and Assistant Dean in the College of Arts and Sciences Mentor: Shanti Parik
E-Commerce Usage In Cement Industries Of Malaysia Berhad
The planning on the development of e-commerce in Cement Industries of Malaysia Berhad (CIMA) is expected to change the way of organisation's operations and improve customer services. However, the potential of e-commerce in improving
customer satisfaction has not been studied very well especially in cement industry sectors. This study reports the results of a survey of 36 cement distributor agents from northern, centre and eastern regions. The aim of this study is to evaluate the factors of business operations, computer technologies friendliness, and obstacles in e-commerce utilisation towards the willingness to participate in e-commerce usage in buying of Blue Lion cement. The results from this study shown that total number of regular customers, transactions per year, annual purchased volume per year, highest volume of cement purchased by the product name of Blue Lion, and ease of use of ecommerce have a significance correlation towards a willingness to participate in ecommerce usage. In addition, distributor agents are gladly to participate with the investment less than RM5,000. Nevertheless, the management of CIMA needs to give a focus on barrier factors in order to improve the number of participation in this project
Anisotropy and Interface structure in magnetic multilayers
It is believed that the interfacial structure can significantly affect the magnetic properties of magnetic multilayer thin films. X-ray scattering techniques provide a powerful method with which to study the bulk and interface morphology in these systems, and are therefore crucial in developing an understanding of the dominant factors influencing the magnitude of the perpendicular magnetic anisotropy (PMA).The inter-relation between magnetic and structural properties of a series of magnetic multilayer thin films is investigated. Magnetometry measurements on a series of Fe/Au multilayers showed that some samples exhibited in-plane magnetization. X-ray data and simulations showed that the interface roughness was high in these samples. However, the formation and propagation of uncorrelated roughness followed a systematic trend for surface growth. On the other hand, x-ray data and simulations for a single 100-bilayer sample showed that the interfaces are much better defined with significantly lower roughness. This was the only sample to show perpendicular anisotropy supposing the suggestion that the absence of PMA in all other samples is associated with high interface roughness. Magnetometry measurements of the PMA in Co/Pt multilayers show an increase in effective anisotropy at about 15 bilayers. X-ray data showed that the roughness of the interfaces was correlated in all samples and that the interfaces were sharp with no detectable interdiffusion. No systematic trend in roughness or crystallographic texture is detected with increasing bilayer repeat X-ray measurements on four series of Co/Pd multilayers show interface roughness independent of bilayer repeat number. For Co/Pt, the in-plane correlation length was independent of bilayer number while for Co/Pd and Fe/Au it increased. A saturation of the in-plane correlation length for the Au/Fe system where island growth of the Au occurs was observed. The out-of-plane correlation length increased with bilayer repeat for Co/Pt and Co/Pd. The interfaces in samples with higher PMA had a fractal parameter close to unity
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