Community detection with spiking neural networks for neuromorphic hardware

We present results related to the performance of an algorithm for community detection which incorporates event-driven computation. We define a mapping which takes a graph G to a system of spiking neurons. Using a fully connected spiking neuron system, with both inhibitory and excitatory synaptic connections, the firing patterns of neurons within the same community can be distinguished from firing patterns of neurons in different communities. On a random graph with 128 vertices and known community structure we show that by using binary decoding and a Hamming-distance based metric, individual communities can be identified from spike train similarities. Using bipolar decoding and finite rate thresholding, we verify that inhibitory connections prevent the spread of spiking patterns.Comment: Conference paper presented at ORNL Neuromorphic Workshop 2017, 7 pages, 6 figure

Pauli Spin Blockade of Heavy Holes in a Silicon Double Quantum Dot

In this work, we study hole transport in a planar silicon metal-oxide-semiconductor based double quantum dot. We demonstrate Pauli spin blockade in the few hole regime and map the spin relaxation induced leakage current as a function of inter-dot level spacing and magnetic field. With varied inter-dot tunnel coupling we can identify different dominant spin relaxation mechanisms. Applying a strong out-of-plane magnetic field causes an avoided singlet-triplet level crossing, from which the heavy hole g-factor $\sim$ 0.93, and the strength of spin-orbit interaction $\sim$ 110 $\mu$eV, can be obtained. The demonstrated strong spin-orbit interaction of heavy hole promises fast local spin manipulation using only electrical fields, which is of great interest for quantum information processing.Comment: 15 pages, 4 figure

HAWAII LONGLINE VESSEL ECONOMICS

Public Economics,

Bandwidth in bolometric interferometry

Bolometric Interferometry is a technology currently under development that will be first dedicated to the detection of B-mode polarization fluctuations in the Cosmic Microwave Background. A bolometric interferometer will have to take advantage of the wide spectral detection band of its bolometers in order to be competitive with imaging experiments. A crucial concern is that interferometers are presumed to be importantly affected by a spoiling effect known as bandwidth smearing. In this paper, we investigate how the bandwidth modifies the work principle of a bolometric interferometer and how it affects its sensitivity to the CMB angular power spectra. We obtain analytical expressions for the broadband visibilities measured by broadband heterodyne and bolometric interferometers. We investigate how the visibilities must be reconstructed in a broadband bolometric interferometer and show that this critically depends on hardware properties of the modulation phase shifters. Using an angular power spectrum estimator accounting for the bandwidth, we finally calculate the sensitivity of a broadband bolometric interferometer. A numerical simulation has been performed and confirms the analytical results. We conclude (i) that broadband bolometric interferometers allow broadband visibilities to be reconstructed whatever the kind of phase shifters used and (ii) that for dedicated B-mode bolometric interferometers, the sensitivity loss due to bandwidth smearing is quite acceptable, even for wideband instruments (a factor 2 loss for a typical 20% bandwidth experiment).Comment: 13 pages, 14 figures, submitted to A&

Nonlinear Torsional Wave Beams

An evolution equation with cubic nonlinearity is presented for a torsional wave beam in an isotropic elastic solid. Analytical solutions are presented for the fundamental and third harmonic in the far field of a uniform circular source. Numerical results are presented for harmonic beam patterns at an intermediate distance between the near and far fields, and for a torsional waveform with shocks.Applied Research Laboratorie

A study into the effectiveness of an education programme for parents and teachers

Introduction: Parents and teachers lack knowledge and self-efficacy when providing postural care to physically disabled children. This can act as a barrier to the successful implementation of therapy. An intervention was developed to improve knowledge and confidence in providing postural care. The aim is to determine whether this intervention improves parents’ and teachers’ knowledge and confidence. Participants and Methods: The intervention includes a 2-hour interactive workshop and follow-up home/school visits delivered in three localities across the south-east of England. The UKC-PostCarD scale, which assesses levels of knowledge and confidence in providing postural care, was used to evaluate the intervention. It is completed at baseline and after the intervention is completed. Focus groups with participants will provide insight into elements that were effective/ineffective.Interviews with children will provide their perspective. Interviews with therapists will consider the feasibility and acceptability of delivery. Results: A mixed-design ANOVA 2 (Time: before vs. after) 9 3 (Area:Kent, Sussex, Surrey) will be used to determine whether knowledge and confidence improved following the intervention. Framework analysis will be used for the focus group and interview data. Qualitative findings will be fed into the overall evaluation. Results will be available by September 2013. Conclusion: If shown to improve confidence and knowledge, we will make this education programme available nationally

POSTED - general questionnaire

This questionnaire is concerned with carers experiences of daytime postural care. This questionnaire may be completed by anyone with experience of providing postural care to a child with a physical disability in a school and/or home environment. This includes parents, teachers and teaching assistants. It is likely that information, training and support needs vary considerably from one person to the next – due to the needs of the child, the type of equipment used, or the environment in which postural care is provided. This questionnaire was developed to enable parents, teachers, and teaching assistants to highlight specific aspects of postural care that they find challenging in order that information, training and support may be appropriately targeted. The questionnaire was originally designed for use in research commissioned by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (grant reference number PB‐PG‐ 0110‐21045). When using/referring to this questionnaire please acknowledge authorship as appropriate. Details of the development of the questionnaire can be found in the following publication. Hotham, S., Hutton, E. & Hamilton‐West, K. E. (2015) Development of a reliable, valid measure to assess parents' and teachers' understanding of postural care for children with physical disabilities: the (UKC‐PostCarD) questionnaire. Child: Care, Health and Development, 41, 1172– 1178

HST Images and Spectra of the Remnant of SN 1885 in M31

Near UV HST images of the remnant of SN 1885 (S And) in M31 show a 0"70 +- 0"05 diameter absorption disk silhouetted against M31's central bulge, at SN 1885's historically reported position. The disk's size corresponds to a linear diameter of 2.5 +- 0.4 pc at a distance of 725 +- 70 kpc, implying an average expansion velocity of 11000 +- 2000 km/s over 110 years. Low-dispersion FOS spectra over 3200-4800 A; reveal that the absorption arises principally from Ca II H & K (equivalent width ~215 A;) with weaker absorption features of Ca I 4227 A; and Fe I 3720 A;. The flux at Ca II line center indicates a foreground starlight fraction of 0.21, which places SNR 1885 some 64 pc to the near side of the midpoint of the M31 bulge, comparable to its projected 55 pc distance from the nucleus. The absorption line profiles suggest an approximately spherically symmetric, bell-shaped density distribution of supernova ejecta freely expanding at up to 13100 +- 1500 km/s. We estimate Ca I, Ca II, and Fe I masses of 2.9(+2.4,-0.6) x 10^-4 M_o, 0.005(+0.016,-0.002) M_o, and 0.013(+0.010,-0.005) M_o respectively. If the ionization state of iron is similar to the observed ionization state of calcium, M_CaII/M_CaI = 16(+42,-5), then the mass of Fe II is 0.21(+0.74,-0.08) M_o, consistent with that expected for either normal or subluminous SN Ia.Comment: 8 pages, including 4 embedded EPS figures, emulateapj.sty style file. Color image at http://casa.colorado.edu/~mcl/sand.shtml . Submitted to Ap