3,671 research outputs found
Adaptive Sentence Boundary Disambiguation
Labeling of sentence boundaries is a necessary prerequisite for many natural
language processing tasks, including part-of-speech tagging and sentence
alignment. End-of-sentence punctuation marks are ambiguous; to disambiguate
them most systems use brittle, special-purpose regular expression grammars and
exception rules. As an alternative, we have developed an efficient, trainable
algorithm that uses a lexicon with part-of-speech probabilities and a
feed-forward neural network. After training for less than one minute, the
method correctly labels over 98.5\% of sentence boundaries in a corpus of over
27,000 sentence-boundary marks. We show the method to be efficient and easily
adaptable to different text genres, including single-case texts.Comment: This is a Latex version of the previously submitted ps file
(formatted as a uuencoded gz-compressed .tar file created by csh script). The
software from the work described in this paper is available by contacting
[email protected]
The asymptotic equivalence of fixed heat flux and fixed temperature thermal boundary conditions for rapidly rotating convection
The influence of fixed temperature and fixed heat flux thermal boundary
conditions on rapidly rotating convection in the plane layer geometry is
investigated for the case of stress-free mechanical boundary conditions. It is
shown that whereas the leading order system satisfies fixed temperature
boundary conditions implicitly, a double boundary layer structure is necessary
to satisfy the fixed heat flux thermal boundary conditions. The boundary layers
consist of a classical Ekman layer adjacent to the solid boundaries that adjust
viscous stresses to zero, and a layer in thermal wind balance just outside the
Ekman layers adjusts the temperature such that the fixed heat flux thermal
boundary conditions are satisfied. The influence of these boundary layers on
the interior geostrophically balanced convection is shown to be asymptotically
weak, however. Upon defining a simple rescaling of the thermal variables, the
leading order reduced system of governing equations are therefore equivalent
for both boundary conditions. These results imply that any horizontal thermal
variation along the boundaries that varies on the scale of the convection has
no leading order influence on the interior convection
Density Functional Theory of doped superfluid liquid helium and nanodroplets
During the last decade, density function theory (DFT) in its static and
dynamic time dependent forms, has emerged as a powerful tool to describe the
structure and dynamics of doped liquid helium and droplets. In this review, we
summarize the activity carried out in this field within the DFT framework since
the publication of the previous review article on this subject [M. Barranco et
al., J. Low Temp. Phys. 142, 1 (2006)]. Furthermore, a comprehensive
presentation of the actual implementations of helium DFT is given, which have
not been discussed in the individual articles or are scattered in the existing
literature. This is an Accepted Manuscript of an article published on August 2,
2017 by Taylor & Francis Group in Int. Rev. Phys. Chem. 36, 621 (2017),
available online: http://dx.doi.org/10.1080/0144235X.2017.1351672Comment: 113 pages, 42 figure
NFC Sensors Based on Energy Harvesting for IoT Applications
The availability of low-cost near-field communication (NFC) devices, the incorporation of NFC readers into most current mobile phones, and the inclusion of energy-harvesting (EH) capabilities in NFC chips make NFC a key technology for the development of green Internet of Things (IoT) applications. In this chapter, an overview of recent advances in the field of battery-less NFC sensors at 13.56Â MHz is provided, and a comparison to other short-range RFID technologies is given. After reviewing power transfer in NFC, recommendations for the practical design of NFC-based sensor tags and NFC readers are made. A list of commercial NFC integrated circuits with energy-harvesting capabilities is also provided. A survey of recent battery-less NFC sensors developed by the group including soil moisture, water content, pH, color, and implanted NFC sensors is done
How Companies Restrain MeansâEnds Decoupling: A Comparative Case Study of CSR Implementation
We use the concept of meansâends decoupling to examine why companies continue to be major contributors to environmental and social problems despite committing increasingly to corporate social responsibility (CSR). Specifically, we ask: How do companies restrain (versus fail to restrain) meansâends decoupling? We answer this question through a comparative case study of four multinational companies with different levels of meansâends decoupling. Based on interviews and secondary data, we inductively identify two distinct approaches to CSR implementation: experimental vs. consistency- oriented CSR implementation. Experimental CSR implementation means that companies (1) produce CSR knowledge about what is hap-pening in specific CSR contexts and use this knowledge to (2) adapt CSR practices to local circumstances â an interplay that restrains meansâends decoupling. Consistency- oriented CSR implementation lacks this interplay between knowledge production and practice adaptation, which fosters meansâends decoupling. Our model of experimental versus consistency- oriented CSR implementation advances two streams of research. First, we advance research on meansâends decoupling by highlighting the importance of experimentation for restraining meansâends decoupling. Second, we advance research on the impact of CSR activities by questioning the widespread assumption that consistency should be at the heart of CSR implementation
Exact electronic states with shallow quantum circuits from global optimisation
Quantum computers promise to revolutionise molecular electronic simulations by overcoming the exponential memory scaling. While electronic wave functions can be represented using a product of fermionic unitary operators, the best ansatz for strongly correlated electronic systems is far from clear. In this contribution, we construct universal wave functions from gate-efficient, spin symmetry-preserving fermionic operators by introducing an algorithm that globally optimises the wave function in the discrete ansatz design and continuous parameter spaces. Our approach maximises the accuracy that can be obtained with near-term quantum circuits and provides a practical route for designing ansÀtze in the future. Numerical simulations for strongly correlated molecules, including water and molecular nitrogen, and the condensed-matter Hubbard model, demonstrate the improved accuracy of gate-efficient quantum circuits for simulating strongly correlated chemistry
MODBASE, a database of annotated comparative protein structure models and associated resources.
MODBASE (http://salilab.org/modbase) is a database of annotated comparative protein structure models. The models are calculated by MODPIPE, an automated modeling pipeline that relies primarily on MODELLER for fold assignment, sequence-structure alignment, model building and model assessment (http:/salilab.org/modeller). MODBASE currently contains 5,152,695 reliable models for domains in 1,593,209 unique protein sequences; only models based on statistically significant alignments and/or models assessed to have the correct fold are included. MODBASE also allows users to calculate comparative models on demand, through an interface to the MODWEB modeling server (http://salilab.org/modweb). Other resources integrated with MODBASE include databases of multiple protein structure alignments (DBAli), structurally defined ligand binding sites (LIGBASE), predicted ligand binding sites (AnnoLyze), structurally defined binary domain interfaces (PIBASE) and annotated single nucleotide polymorphisms and somatic mutations found in human proteins (LS-SNP, LS-Mut). MODBASE models are also available through the Protein Model Portal (http://www.proteinmodelportal.org/)
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Prerendered User Interfaces for Higher-Assurance Electronic Voting
We propose an electronic voting machine architecture in which the voting user interface is prerendered and published before election day. The prerendered user interface is a verifiable artifactâan electronic sample ballotâenabling public participation in the review, verification, usability testing, and accessibility testing of the ballot. Preparing the user interface outside of the voting machine dramatically reduces the amount and difficulty of software verification required to assure the correctness of the election result. We present a design for a high-assurance touchscreen voting machine that supports a wide range of user interface styles and demonstrate its feasibility by implementing it in less than 300 lines of Python code
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