Visualising ergonomics data for design

Existing ergonomics data are not effectively used by designers; this is mainly because the data are not presented in a designer-friendly format. In order to help designers make better use of ergonomics data, we explored the potential of representing existing ergonomics data in a more dynamic and visual way, and making them look more relevant to design. The Cambridge Engineering Selector (CES) was adopted to turn static ergonomics data into manipulative and comparative data sets. Contextual information in a visual format was added; clearer illustrations and scenarios relevant to design were developed; design case studies were compiled and linked to the relevant ergonomics data sets – the process resulted in a new design support tool: the ErgoCES. The tool was consequently brought to both design students and professionals for evaluation. The results suggested that the ErgoCES had helped making ergonomics data more accessible to designers, and many new features (e.g. scenarios and case studies) were highly valued by the designers. Among the participants, 100% of the design students and 79% of the professionals indicated that they would use the tool when it becomes widely available.The research project is funded by the Engineering and Physical Sciences Research Council, Grant EP/F0 32145/1. The authors would like to thank all the participants for helping evaluating the tool. Hua Dong is currently sponsored by The Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning

Undercover EUV Solar Jets Observed by the Interface Region Imaging Spectrograph

It is well-known that extreme ultraviolet emission emitted at the solar surface is absorbed by overlying cool plasma. Especially in active regions dark lanes in EUV images suggest that much of the surface activity is obscured. Simultaneous observations from IRIS, consisting of UV spectra and slit-jaw images give vital information with sub-arcsecond spatial resolution on the dynamics of jets not seen in EUV images. We studied a series of small jets from recently formed bipole pairs beside the trailing spot of active region 11991, which occurred on 2014 March 5 from 15:02:21 UT to 17:04:07 UT. There were collimated outflows with bright roots in the SJI 1400 {\AA} (transition region) and 2796 {\AA} (upper chromosphere) that were mostly not seen in AIA 304 {\AA} (transition region) and AIA 171 \AA\ (lower corona) images. The Si IV spectra show strong blue-wing but no red-wing enhancements in the line profiles of the ejecta for all recurrent jets indicating outward flows without twists. We see two types of Mg II line profiles produced by the jets spires: reversed and non-reversed. Mg II lines remain optically thick but turn into optically thin in the highly Doppler shifted wings.The energy flux contained in each recurrent jet is estimated using a velocity differential emission measure technique which measures the emitting power of the plasma as a function of line-of-sight velocity. We found that all the recurrent jets release similar energy (10$^8$ erg cm$^{-2}$ s$^{-1}$ ) toward the corona and the downward component is less than 3\%.Comment: Accepted for publication in ApJ, 6 fiugre

Small eigenvalues of large Hankel matrices:The indeterminate case

In this paper we characterise the indeterminate case by the eigenvalues of the Hankel matrices being bounded below by a strictly positive constant. An explicit lower bound is given in terms of the orthonormal polynomials and we find expresions for this lower bound in a number of indeterminate moment problems.Comment: 14 pages, 1 figur

Improvement of indoor VLC network downlink scheduling and resource allocation

Indoor visible light communications (VLC) combines illumination and communication by utilizing the high-modulation-speed of LEDs. VLC is anticipated to be complementary to radio frequency communications and an important part of next generation heterogeneous networks. In order to make the maximum use of VLC technology in a networking environment, we need to expand existing research from studies of traditional point-to-point links to encompass scheduling and resource allocation related to multi-user scenarios. This work aims to maximize the downlink throughput of an indoor VLC network, while taking both user fairness and time latency into consideration. Inter-user interference is eliminated by appropriately allocating LEDs to users with the aid of graph theory. A three-term priority factor model is derived and is shown to improve the throughput performance of the network scheduling scheme over those previously reported. Simulations of VLC downlink scheduling have been performed under proportional fairness scheduling principles where our newly formulated priority factor model has been applied. The downlink throughput is improved by 19.6% compared to previous two-term priority models, while achieving similar fairness and latency performance. When the number of users grows larger, the three-term priority model indicates an improvement in Fairness performance compared to two-term priority model scheduling

Magic Wavelengths for Terahertz Clock Transitions

Magic wavelengths for laser trapping of boson isotopes of alkaline-earth Sr, Ca and Mg atoms are investigated while considering terahertz clock transitions between the $^{3}P_{0}, ^{3}P_{1}, ^{3}P_{2}$ metastable triplet states. Our calculation shows that magic wavelengths of trapping laser do exist. This result is important because those metastable states have already been used to realize accurate clocks in the terahertz frequency domain. Detailed discussions for magic wavelength for terahertz clock transitions are given in this paper.Comment: 7 page

A 3D radiative transfer framework: X. Arbitrary Velocity Fields in the Co-moving Frame

3-D astrophysical atmospheres will have random velocity fields. We seek to combine the methods we have developed for solving the 1-D problem with arbitrary flows to those that we have developed for solving the fully 3-D relativistic radiative transfer problem in the case of monotonic flows. The methods developed in the case of 3-D atmospheres with monotonic flows, solving the fully relativistic problem along curves defined by an affine parameter, are very flexible and can be extended to the case of arbitrary velocity fields in 3-D. Simultaneously, the techniques we developed for treating the 1-D problem with arbitrary velocity fields are easily adapted to the 3-D problem. The algorithm we present allows the solution of 3-D radiative transfer problems that include arbitrary wavelength couplings. We use a quasi-analytic formal solution of the radiative transfer equation that significantly improves the overall computation speed. We show that the approximate lambda operator developed in previous work gives good convergence, even neglecting wavelength coupling. Ng acceleration also gives good results. We present tests that are of similar resolution to what has been presented using Monte-Carlo techniques, thus our methods will be applicable to problems outside of our test setup. Additional domain decomposition parallelization strategies will be explored in future work.Comment: 9 pages, 9 figures, A&A, in press, new version matches copy edited version, definition restore

Continuous Charge Modulated Diagonal Phase in Manganites

We present a novel ground state that explain the continuous modulated charge diagonal order recently observed in manganese oxides, at hole densities $x$ larger than one half. In this diagonal phase the charge is modulated with a predominant Fourier component inversely proportional to $1-x$. Magnetically this state consist of antiferromagnetic coupled zig-zag chains. For a wide range of relevant physical parameters as electron-phonon coupling, antiferromagnetic interaction between Mn ions and on-site Coulomb repulsion, the diagonal phase is the ground state of the system. The diagonal phase is favored by the modulation of the hopping amplitude along the zig-zag chains, and it is stabilized with respect to the one dimensional straight chain by the electron phonon coupling. For realistic estimation of the physical parameters, the diagonal modulation of the electron density is only a small fraction of the average charge, a modulation much smaller than the obtained by distributing Mn$^{+3}$ and Mn$^{+4}$ ions. We discuss also the spin and orbital structure properties of this new diagonal phase.Comment: 4 pages, 4 figures include