Context. Observations reveal an increase with height of the line width of several coronal spectral lines probably caused by outwardly propagating Alfvén waves. However, the spectral line width sometimes shows a sudden decrease at a height ∼ 0.1–0.2 R⊙, where the ratio of sound to Alfvén speeds may approach unity. Aims. To explain the observed line width reduction in terms of the energy conversi...

In this work, the performance of a 640 512 long-wavelength resonant quantum well infrared photodetector (R-QWIP) focal plane array (FPA) was evaluated as a function of operating temperature, bias, and photon flux using an F/2.2 optic. From these FPA measurements an assessment of the dark current, noise, conversion efficiency and noise-equivalent temperature difference is provided herein. Histog...

In this paper we demonstrate that spectral conversion can be successfully applied to the speech enhancement problem as a feature denoising method. The enhanced spectral features can be used in the context of the Kalman filter for estimating the clean speech signal. In essence, instead of estimating the clean speech features and the clean speech signal using the iterative Kalman filter, we show ...

Spectral control of the emissivity of surfaces is essential in applications such as solar thermal energy and thermophotovoltaic energy conversion in order to achieve the highest conversion efficiencies possible. We investigated surfaces consisting of periodic, nanoscale V-grooves coated with aperiodic metal-dielectric stacks. This approach combines impedance matching using tapered metallic feat...

This paper proposes a spectral conversion technique based on a new statisticalmodel which includes time-sequence matching. In conventional GMM-based approaches, the Dynamic Programming (DP) matching between source and target feature sequences is performed prior to the training of GMMs. Although a similarity measure of two frames, e.g., the Euclid distance is typically adopted, this might be ina...

We describe an experiment in which photon pairs from a pulsed parametric down-conversion (PDC) source were coupled into single-mode fibers with heralding efficiencies as high as 70%. Heralding efficiency or mode preparation efficiency is defined as the probability of finding a photon in a fiber in a definite state, given the detection of its twin. Heralding efficiencies were obtained for a rang...

A simple and fast voice conversion method based only on vowel information is proposed. The proposed method relies on empirical distribution of perceptual spectral distances between representative examples of each vowel segment extracted using TANDEM-STRAIGHT spectral envelope estimation procedure [1]. Mapping functions of vowel spectra are designed to preserve vowel space structure defined by t...

The Planck High Frequency Instrument (HFI) spectral response was determined through a series of ground based tests conducted with the HFI focal plane in a cryogenic environment prior to launch. The main goal of the spectral transmission tests was to measure the relative spectral response (including the level of out-of-band signal rejection) of all HFI detectors to a known source of electromagne...

We propose and demonstrate a novel implementation of spectral-shearing interferometry (SSI) for reconstructing the electric field of ultrashort pulses by utilizing asymmetric group velocity matching in a long nonlinear crystal. The proposed configuration eliminates the requirement for a linearly chirped auxiliary pulse that is in common in all existing SSI methods, relying on nonlinear conversi...

Voice conversion, as considered in this paper, is defined as modifying the speech signal of one speaker (source speaker) so that it sounds as if it had been pronounced by a different speaker (target speaker). Our contribution includes the design of a new methodology for representing the relationship between two sets of spectral envelopes. The proposed method is based on the use of a Gaussian mi...