8,139 research outputs found

    Time-scale and pitch modifications of speech signals and resynthesis from the discrete short-time Fourier transform

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    The modification methods described in this paper combine characteristics of PSOLA-based methods and algorithms that resynthesize speech from its short-time Fourier magnitude only. The starting point is a short-time Fourier representation of the signal. In the case of duration modification, portions, in voiced speech corresponding to pitch periods, are removed from or inserted in this representation. In the case of pitch modification, pitch periods are shortened or extended in this representation, and a number of pitch periods is inserted or removed, respectively. Since it is an important tool for both duration and pitch modification, the resynthesis-from-short-time-Fourier-magnitude-only method of Griffin and Lim (1984) and Griffin et al. (1984) is reviewed and adapted. Duration and pitch modification methods and their results are presented.\ud \u

    TEM, XRD, and Thermal Stability of Adsorbed Paranitrophenol on DDOAB Organoclay

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    Water purification is of extreme importance to modern society. Organoclays through adsorption of recalcitrant organics provides one mechanism for the removal of these molecules. The organoclay was synthesised through ion exchange with dimethyldioctadecylammonium bromide labeled as DDOAB of formula (CH3(CH2)17)2NBr(CH3)2. Paranitrophenol was adsorbed on the organoclay at a range of concentrations according to the cation exchange capacity (CEC) of the host montmorillonite. The paranitrophenol in solution was analysed by a UV-260 spectrophotometer at 317nm, with detection limits being 0.05mg/L. The expansion of the montmorillonite was studied by a combination of X-ray diffraction and transmission electron microscopy. Upon adsorption of the paranitrophenol the basal spacing decreased. The thermal stability of the organoclay was determined by a combination of thermogravimetry and infrared emission spectroscopy. The surfactant molecule DDOAB combusts at 166, 244 and 304 degrees Celsius and upon intercalation into Na-montmorillonite is retained up to 389 degrees Celsius thus showing the organoclay is stable to significantly high temperatures well above the combustion/decomposition temperature of the organoclay

    Autonomous Demand Side Management Based on Energy Consumption Scheduling and Instantaneous Load Billing: An Aggregative Game Approach

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    In this paper, we investigate a practical demand side management scenario where the selfish consumers compete to minimize their individual energy cost through scheduling their future energy consumption profiles. We propose an instantaneous load billing scheme to effectively convince the consumers to shift their peak-time consumption and to fairly charge the consumers for their energy consumption. For the considered DSM scenario, an aggregative game is first formulated to model the strategic behaviors of the selfish consumers. By resorting to the variational inequality theory, we analyze the conditions for the existence and uniqueness of the Nash equilibrium (NE) of the formulated game. Subsequently, for the scenario where there is a central unit calculating and sending the real-time aggregated load to all consumers, we develop a one timescale distributed iterative proximal-point algorithm with provable convergence to achieve the NE of the formulated game. Finally, considering the alternative situation where the central unit does not exist, but the consumers are connected and they would like to share their estimated information with others, we present a distributed agreement-based algorithm, by which the consumers can achieve the NE of the formulated game through exchanging information with their immediate neighbors.Comment: 11 pages, 7 figure

    Band-edge-induced Bragg diffraction in two-dimensional photonic crystals

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    Two-dimensional photonic crystals composed of two orthogonal volume diffraction gratings have been photogenerated in photopolymers. When the read beam is set at the Bragg angle, the diffraction efficiency of the transmission grating is strongly enhanced at the band edge of the reflection grating recorded in the material. Such a device provides Bragg operation and enhancement of the diffraction efficiency of the thin diffraction grating together with good wavelength selectivity. Such advantages could be interesting for optical signal processing

    Exploring the Atmosphere of Neoproterozoic Earth: The Effect of O2_{2} on Haze Formation and Composition

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    Previous studies of haze formation in the atmosphere of the Early Earth have focused on N2_{2}/CO2_{2}/CH4_{4} atmospheres. Here, we experimentally investigate the effect of O2_{2} on the formation and composition of aerosols to improve our understanding of haze formation on the Neoproterozoic Earth. We obtained in situ size, particle density, and composition measurements of aerosol particles produced from N2_{2}/CO2_{2}/CH4_{4}/O2_{2} gas mixtures subjected to FUV radiation (115-400 nm) for a range of initial CO2_{2}/CH4_{4}/O2_{2} mixing ratios (O2_{2} ranging from 2 ppm to 0.2\%). At the lowest O2_{2} concentration (2 ppm), the addition increased particle production for all but one gas mixture. At higher oxygen concentrations (20 ppm and greater) particles are still produced, but the addition of O2_{2} decreases the production rate. Both the particle size and number density decrease with increasing O2_{2}, indicating that O2_{2} affects particle nucleation and growth. The particle density increases with increasing O2_{2}. The addition of CO2_{2} and O2_{2} not only increases the amount of oxygen in the aerosol, but it also increases the degree of nitrogen incorporation. In particular, the addition of O2_{2} results in the formation of nitrate bearing molecules. The fact that the presence of oxygen bearing molecules increases the efficiency of nitrogen fixation has implications for the role of haze as a source of molecules required for the origin and evolution of life. The composition changes also likely affect the absorption and scattering behavior of these particles but optical properties measurements are required to fully understand the implications for the effect on the planetary radiative energy balance and climate.Comment: 15 pages, 3 tables, 8 figures, accepted in Astrophysical Journa

    Bayesian Nonlinear Tensor Regression with Functional Fused Elastic Net Prior

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    Tensor regression methods have been widely used to predict a scalar response from covariates in the form of a multiway array. In many applications, the regions of tensor covariates used for prediction are often spatially connected with unknown shapes and discontinuous jumps on the boundaries. Moreover, the relationship between the response and the tensor covariates can be nonlinear. In this article, we develop a nonlinear Bayesian tensor additive regression model to accommodate such spatial structure. A functional fused elastic net prior is proposed over the additive component functions to comprehensively model the nonlinearity and spatial smoothness, detect the discontinuous jumps, and simultaneously identify the active regions. The great flexibility and interpretability of the proposed method against the alternatives are demonstrated by a simulation study and an analysis on facial feature data
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