20,117 research outputs found

    Giant magnetoimpedance in crystalline Mumetal

    Full text link
    We studied giant magnetoimpedance (GMI) effect in commercial crystalline Mumetal, with the emphasis to sample thickness dependence and annealing effects. By using appropriate heat treatment one can achieve GMI ratios as high as 310%, and field sensitivity of about 20%/Oe, which is comparable to the best GMI characteristics obtained for amorphous and nanocrystalline soft magnetic materials.Comment: 8 pages, 3 figure

    The effects of graded motor imagery and its components on chronic pain: A systematic review and meta-analysis

    Get PDF
    This is the post-print version of the final paper published in The Journal of Pain. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 The American Pain Society.Graded motor imagery (GMI) is becoming increasingly used in the treatment of chronic pain conditions. The objective of this systematic review was to synthesize all evidence concerning the effects of GMI and its constituent components on chronic pain. Systematic searches were conducted in 10 electronic databases. All randomized controlled trials (RCTs) of GMI, left/right judgment training, motor imagery, and mirror therapy used as a treatment for chronic pain were included. Methodological quality was assessed using the Cochrane risk of bias tool. Six RCTs met our inclusion criteria, and the methodological quality was generally low. No effect was seen for left/right judgment training, and conflicting results were found for motor imagery used as stand-alone techniques, but positive effects were observed for both mirror therapy and GMI. A meta-analysis of GMI versus usual physiotherapy care favored GMI in reducing pain (2 studies, n = 63; effect size, 1.06 [95% confidence interval, .41, 1.71]; heterogeneity, I2 = 15%). Our results suggest that GMI and mirror therapy alone may be effective, although this conclusion is based on limited evidence. Further rigorous studies are needed to investigate the effects of GMI and its components on a wider chronic pain population.NHMR

    The chain rule implies Tsirelson's bound: an approach from generalized mutual information

    Full text link
    In order to analyze an information theoretical derivation of Tsirelson's bound based on information causality, we introduce a generalized mutual information (GMI), defined as the optimal coding rate of a channel with classical inputs and general probabilistic outputs. In the case where the outputs are quantum, the GMI coincides with the quantum mutual information. In general, the GMI does not necessarily satisfy the chain rule. We prove that Tsirelson's bound can be derived by imposing the chain rule on the GMI. We formulate a principle, which we call the no-supersignalling condition, which states that the assistance of nonlocal correlations does not increase the capability of classical communication. We prove that this condition is equivalent to the no-signalling condition. As a result, we show that Tsirelson's bound is implied by the nonpositivity of the quantitative difference between information causality and no-supersignalling.Comment: 23 pages, 8 figures, Added Section 2 and Appendix B, result unchanged, Added reference

    A General Framework for Transmission with Transceiver Distortion and Some Applications

    Full text link
    A general theoretical framework is presented for analyzing information transmission over Gaussian channels with memoryless transceiver distortion, which encompasses various nonlinear distortion models including transmit-side clipping, receive-side analog-to-digital conversion, and others. The framework is based on the so-called generalized mutual information (GMI), and the analysis in particular benefits from the setup of Gaussian codebook ensemble and nearest-neighbor decoding, for which it is established that the GMI takes a general form analogous to the channel capacity of undistorted Gaussian channels, with a reduced "effective" signal-to-noise ratio (SNR) that depends on the nominal SNR and the distortion model. When applied to specific distortion models, an array of results of engineering relevance is obtained. For channels with transmit-side distortion only, it is shown that a conventional approach, which treats the distorted signal as the sum of the original signal part and a uncorrelated distortion part, achieves the GMI. For channels with output quantization, closed-form expressions are obtained for the effective SNR and the GMI, and related optimization problems are formulated and solved for quantizer design. Finally, super-Nyquist sampling is analyzed within the general framework, and it is shown that sampling beyond the Nyquist rate increases the GMI for all SNR. For example, with a binary symmetric output quantization, information rates exceeding one bit per channel use are achievable by sampling the output at four times the Nyquist rate.Comment: 32 pages (including 4 figures, 5 tables, and auxiliary materials); submitted to IEEE Transactions on Communication

    On the Information Loss of the Max-Log Approximation in BICM Systems

    Full text link
    We present a comprehensive study of the information rate loss of the max-log approximation for MM-ary pulse-amplitude modulation (PAM) in a bit-interleaved coded modulation (BICM) system. It is widely assumed that the calculation of L-values using the max-log approximation leads to an information loss. We prove that this assumption is correct for all MM-PAM constellations and labelings with the exception of a symmetric 4-PAM constellation labeled with a Gray code. We also show that for max-log L-values, the BICM generalized mutual information (GMI), which is an achievable rate for a standard BICM decoder, is too pessimistic. In particular, it is proved that the so-called "harmonized" GMI, which can be seen as the sum of bit-level GMIs, is achievable without any modifications to the decoder. We then study how bit-level channel symmetrization and mixing affect the mutual information (MI) and the GMI for max-log L-values. Our results show that these operations, which are often used when analyzing BICM systems, preserve the GMI. However, this is not necessarily the case when the MI is considered. Necessary and sufficient conditions under which these operations preserve the MI are provided

    High-Sensitivity Magnetic Sensors Based on GMI Microwire-SAW IDT Design

    Get PDF
    This work presents a design approach for a highly sensitive, miniaturized magnetic sensor. The design makes use of GMI microwires and a multi-electrode SAW IDT. The use of SAW IDTs allows for the magnetic effect of the GMI microwire to be measured through the transduction process. This approach permits simultaneous measurement at different frequencies of operation, enabling highly sensitive measurement over a wide range of magnetic fields. This technique may find application in magnetic sensing for non-invasive battery SOC measurement

    Growth Motivation and Well-Being in the U.S., Japan, Guatemala, and India

    Get PDF
    The present study examined how the Growth Motivation Index (GMI; J. J. Bauer et al., 2015) related to well-being and identity exploration in samples from the U.S., Japan, Guatemala, and India. The GMI has two facets. GMI-reflective measures the motive to cultivate critical self-reflection and intellectual development, whereas GMI-experiential measures the motive to cultivate personally meaningful activities and relationships. We expected and found that, when comparing the two GMI facets simultaneously, GMI-reflective predicted well-being in countries ranked as having collectivist but not individualist cultures, whereas GMI-experiential predicted well-being in countries ranked as having individualist but not collectivist cultures. GMI-reflective predicted identity exploration across cultures. Implications for growth motivation and culture are discussed

    Giant magnetoimpedance in Vitrovac amorphous ribbons over [0.3-400 MHz] frequency range

    Full text link
    Giant magneto impedance (GMI) effect for as-cast Vitrovac®^{\textrm{\scriptsize\textregistered}} amorphous ribbons (Vacuumschmelze, Germany) in two configurations (parallel and normal to the ribbon axis) is studied over the frequency range [0.3-400 MHz] and under static magnetic fields -160 Oe <Hdc<< H_{dc} < +160 Oe. A variety of peak features and GMI ratio values, falling within a small field range, are observed and discussed.Comment: Paper submitted to International Conference on Magnetism 2003 (ICM Rome 2003
    • …
    corecore