103,268 research outputs found

    Managing the noisy glaucomatous test data by self organising maps

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    One of the main difficulties in obtaining reliable data from patients in glaucomatous tests is the measurement noise caused by the learning effect, inattention, failure of fixation, fatigue, etc. Using Kohonen's self-organising feature maps, we have developed a computational method to distinguish between the noise and true measurement. This method has been shown to provide a satisfactory way of locating and rejecting noise in the test data, an improvement over conventional statistical method

    Physical modelling of amorphous thermoplastic polymer and numerical simulation of micro hot embossing process

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    Micro hot embossing process is considered as one of the most promising micro replication processes for manufacturing of polymeric components, especially for the high aspect ratio components and large surface structural components. A large number of hot embossing experimental results have been published, the material modelling and processes simulation to improve the quality of micro replication by hot embossing process are still lacking. This paper consists to 3D modelling of micro hot embossing process with amorphous thermoplastic polymers, including the mechanical characterisation of polymers properties, identification of the viscoelastic behaviour law of the polymers, numerical simulation and experimental investigation of micro hot embossing process. Static compression creep tests have been carried out to investigate the selected polymers’ viscoelastic properties. The Generalized Maxwell model has been proposed to describe the relaxation modulus of the polymers and good agreement has been observed. The numerical simulation of the hot embossing process in 3D has been achieved by taking into account the viscoelastic behaviour of the polymers. The microfluidic devices with the thickness of 2 mm have been elaborated by hot embossing process. The hot embossing process has been carried out using horizontal injection/compression moulding equipment, especially developed for this study. A complete compression mould tool, equipped with the heating system, the cooling system, the ejection system and the vacuum system, has been designed and elaborated in our research. Polymer-based microfluidic devices have been successfully replicated by the hot embossing process using the compression system developed. Proper agreement between the numerical simulation and the experimental elaboration has been observed. It shows strong possibility for the development of the 3D numerical model to optimize the micro hot embossing process in the future

    Guest editorial

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    3-D Microwave Imaging for Breast Cancer

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    We introduce a novel microwave imaging technique for breast cancer detection. Our approach provides a one-pass inverse image solution, which is completely new and unprecedented, unrelated to tomography or radar-based algorithms, and unburdened by the optimization toil which lies at the heart of numerical schemes. It operates effectively at a single frequency, without requiring the bandwidth of radar techniques. Underlying this new method is our unique Field Mapping Algorithm (FMA), which transforms electromagnetic fields acquired upon one surface, be it through outright measurement or some auxiliary computation, into those upon another in an exact sense

    AI for public health: Self-screening for eye diseases

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    A software-based visual-field testing (perimetry) system is described which incorporates several AI components, including machine learning, an intelligent user interface and pattern discovery. This system has been successfully used for self-screening in several different public environment

    A Codazzi-like equation and the singular set for C1C^{1} smooth surfaces in the Heisenberg group

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    In this paper, we study the structure of the singular set for a C1C^{1} smooth surface in the 33-dimensional Heisenberg group H1\boldsymbol{H}_{1}. We discover a Codazzi-like equation for the pp-area element along the characteristic curves on the surface. Information obtained from this ordinary differential equation helps us to analyze the local configuration of the singular set and the characteristic curves. In particular, we can estimate the size and obtain the regularity of the singular set. We understand the global structure of the singular set through a Hopf-type index theorem. We also justify that Codazzi-like equation by proving a fundamental theorem for local surfaces in H1\boldsymbol{H}_{1}.Comment: 64 pages, 17 figure

    Radiative Kaon Decays K±π±π0γK^\pm\to\pi^\pm\pi^0\gamma and Direct CP Violation

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    It is stressed that a measurement of the electric dipole amplitude for direct photon emission in \kpm decays through its interference with inner bremsstrahlung is important for differentiating among various models. Effects of amplitude CP violation in the radiative decays of the charged kaon are analyzed in the Standard Model in conjunction with the large NcN_c approach. We point out that gluon and electromagnetic penguin contributions to the CP-violating asymmetry between the Dalitz plots of \kpm are of equal weight. The magnitude of CP asymmetry ranges from 2×1062\times 10^{-6} to 1×1051\times 10^{-5} when the photon energy in the kaon rest frame varies from 50 MeV to 170 MeV.Comment: Latex, 11 pages, ITP-SB-93-36, IP-ASTP-22-9

    Measuring dark energy with the EisoEpE_{\rm iso}-E_{\rm p} correlation of gamma-ray bursts using model-independent methods

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    In this paper, we use two model-independent methods to standardize long gamma-ray bursts (GRBs) using the EisoEpE_{\rm iso}-E_{\rm p} correlation, where EisoE_{\rm iso} is the isotropic-equivalent gamma-ray energy and EpE_{\rm p} is the spectral peak energy. We update 42 long GRBs and try to make constraint on cosmological parameters. The full sample contains 151 long GRBs with redshifts from 0.0331 to 8.2. The first method is the simultaneous fitting method. The extrinsic scatter σext\sigma_{\rm ext} is taken into account and assigned to the parameter EisoE_{\rm iso}. The best-fitting values are a=49.15±0.26a=49.15\pm0.26, b=1.42±0.11b=1.42\pm0.11, σext=0.34±0.03\sigma_{\rm ext}=0.34\pm0.03 and Ωm=0.79\Omega_m=0.79 in the flat Λ\LambdaCDM model. The constraint on Ωm\Omega_m is 0.55<Ωm<10.55<\Omega_m<1 at the 1σ\sigma confidence level. If reduced χ2\chi^2 method is used, the best-fit results are a=48.96±0.18a=48.96\pm0.18, b=1.52±0.08b=1.52\pm0.08 and Ωm=0.50±0.12\Omega_m=0.50\pm0.12. The second method is using type Ia supernovae (SNe Ia) to calibrate the EisoEpE_{\rm iso}-E_{\rm p} correlation. We calibrate 90 high-redshift GRBs in the redshift range from 1.44 to 8.1. The cosmological constraints from these 90 GRBs are Ωm=0.230.04+0.06\Omega_m=0.23^{+0.06}_{-0.04} for flat Λ\LambdaCDM, and Ωm=0.18±0.11\Omega_m=0.18\pm0.11 and ΩΛ=0.46±0.51\Omega_{\Lambda}=0.46\pm0.51 for non-flat Λ\LambdaCDM. For the combination of GRB and SNe Ia sample, we obtain Ωm=0.271±0.019\Omega_m=0.271\pm0.019 and h=0.701±0.002h=0.701\pm0.002 for the flat Λ\LambdaCDM, and for the non-flat Λ\LambdaCDM, the results are Ωm=0.225±0.044\Omega_m=0.225\pm0.044, ΩΛ=0.640±0.082\Omega_{\Lambda}=0.640\pm0.082 and h=0.698±0.004h=0.698\pm0.004. These results from calibrated GRBs are consistent with that of SNe Ia. Meanwhile, the combined data can improve cosmological constraints significantly, comparing to SNe Ia alone. Our results show that the EisoEpE_{\rm iso}-E_{\rm p} correlation is promising to probe the high-redshift universe.Comment: 10 pages, 6 figures, 4 table, accepted by A&A. Table 4 contains calibrated distance moduli of GRB
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