Compositional Morphology for Word Representations and Language Modelling

This paper presents a scalable method for integrating compositional morphological representations into a vector-based probabilistic language model. Our approach is evaluated in the context of log-bilinear language models, rendered suitably efficient for implementation inside a machine translation decoder by factoring the vocabulary. We perform both intrinsic and extrinsic evaluations, presenting results on a range of languages which demonstrate that our model learns morphological representations that both perform well on word similarity tasks and lead to substantial reductions in perplexity. When used for translation into morphologically rich languages with large vocabularies, our models obtain improvements of up to 1.2 BLEU points relative to a baseline system using back-off n-gram models.Comment: Proceedings of the 31st International Conference on Machine Learning (ICML

Extreme ultraviolet emission lines of Ni xii in laboratory and solar spectra

A linear force-free field solution is presented in cylindrical coordinates, formulated in terms of trigonometric and Bessel functions. A numerical exploration has revealed that this solution describes magnetic field lines that meander in Cartesian space, as well as field lines that lie on toroidal flux surfaces. These tori are in (or close to) the plane perpendicular to the cylindrical axis. Nested tori, as well as tori with shells that have finite thickness, were found. The parameter space of the solution shows that the tori exist within a bounded range of values

A new family of solutions of the force-free field equation

A new family of solutions has been found for force-free magnetic fields and Beltrami flows, which admits a complete classification in terms of the eigenvalues of the problem. In the absence of boundary values to determine them uniquely, the eigenvalues correspond to the entire set of real numbers, except for zero. The eigenvalues are degenerate in that each eigenvalue has many eigensolutions associated with it. For each eigensolution we have been able to identify sets of equilibrium or null points and lines. The linear mappings of these null points and lines are all unstable. Finally, we derive the first integral of energy associated with this family of solutions

Investigating the self-perceived acquired competencies of humanities graduates at a South African university

The primary objective of this study was to investigate the self-perceived competencies acquired by humanities graduates at a South African university. This self-assessment enables graduates to assess their strengths and weaknesses regarding their competencies and estimate their employability. The secondary objective was to measure the employment status of humanities graduates. The study followed a quantitative approach using a cross-sectional survey design. The convenience sampling method was used since the self-administered questionnaire was distributed to graduates at two graduation ceremonies. Independent samples t-tests were done to compare the mean scores on the six dimensions of the competencies scale between gender, schools and degrees. Chi-square tests were done to establish whether there are associations between gender, faculty schools, degrees and employment status. Spearman rank-order correlation was performed to measure the correlations between the six factors of the competencies scale. The six individual competencies that scored the highest means were: “(1) tolerance, appreciation of different points of view, (2) written communication skills, (3) critical thinking, (4) English language proficiency, (5) working in a team, and (6) taking responsibility for decisions”. A follow-up study should be done among employers to determine what competencies they require from humanities graduates

The structure of force-free magnetic fields

Incontrovertible evidence is presented that the force-free magnetic fields exhibit strong stochastic behavior. Arnold’s solution is given with the associated first integral of energy. A subset of the solution is shown to be non-ergodic whereas the full solution is shown to be ergodic. The first integral of energy is applied to the study of these fields to prove that the equilibrium points of such magnetic configurations are saddle points. Finally, the potential function of the first integral of energy is shown to be a member of the Helmholtz family of solutions. Numerical results corroborate the theoretical conclusions and demonstrate the robustness of the energy integral, which remains constant for arbitrarily long computing time

A review of colour-marking techniques used on vultures in southern Africa

This document aims to provide the background to and motivation for the decision by the Birds of Prey Working Group of South Africa to implement the use of patagial tags for the colour-marking of vultures, under the auspices of the Sasol Vulture Monitoring Project. Information is provided on the reasons for the review of colour-marking before 2006 and the various alternative options considered and tested during 2005. Vulture News Vol. 56 () 2007: pp.52-6