Time-Varying Bandpass Filter Based on Assisted Signals for AM-FM Signal Separation: A Revisit

In this paper, a new signal separation method mainly for AM-FM components blended in noises is revisited based on the new derived time-varying bandpass filter (TVBF), which can separate the AM-FM components whose frequencies have overlapped regions in Fourier transform domain and even have crossed points in time-frequency distribution (TFD) so that the proposed TVBF seems like a “soft-cutter” that cuts the frequency domain to snaky slices with rational physical sense. First, the Hilbert transform based decomposition is analyzed for the analysis of nonstationary signals. Based on the above analysis, a hypothesis under a certain condition that AM-FM components can be separated successfully based on Hilbert transform and the assisted signal is developed, which is supported by representative experiments and theoretical performance analyses on a error bound that is shown to be proportional to the product of frequency width and noise variance. The assisted signals are derived from the refined time-frequency distributions via image fusion and least squares optimization. Experiments on man-made and real-life data verify the efficiency of the proposed method and demonstrate the advantages over the other main methods.

Hilbert transform and its application to modulation of capillary gravity waves

In this paper, the following important problem is answered: Under what condition can the Hilbert transform be put in the simple form. Then, using the Hilbert technique, it is demonstrated that, with some relative weak restrictions, the particle motion at the sea surface and energy transmission may be obtained from a wave record. The analysis show that for the two-dimensional and narrow-band mo- tion (or a physical phenomena, such as capillary waves breaking, which satisfy the narrow-band approx- imation) the local kinetic energy fluctuates in time as the envelope equared multiplied by a constant factor and can be obtained directly from a wave record. It is pointed that the local fluctuatiom of the potential energy as well as the local fluctuations of the total energy can be separated into a slowly varying part and a more rapid oscillating Part. Both Parts can be evaluated by meaas of the Hilbert transform. Finally, a physical interpretation of the envelope of the two-dimensional capillary waves as well as the method for wave group analysis is presented.

A goal-based approach to the identification of essential transformation variables in support of the implementation of the 2030 agenda for sustainable development

The United Nations’2030 Agenda for Sustainable Development sets seventeen Sustainable Development Goals(SDGs)to be achieved by 2030.Earth observation are needed that can support the development and validation of transformation policies to make progress towards the SDGs.A participatory and inclusive goal-based approach(GBA)is introduced that links societal goals,targets and indicators to Essential Transformation Variables(ETVs)of the human and non-human environment.The GBA is complementary to the widely used expertbased approach.The GBA is applied to the SDGs at the goal,target and indicator levels.The high-level conceptual model used for the SDGs is humanity embedded in the Earth’s life-support system(ELSS).At the goal level,very few of the SDGs are directly focusing on the ELSS and its physiology.Most of the SDG Targets focus on transformations in society and the built environment.Having targets that explicitly focus on the physiology of the ELSS would be important for sustainability.Most of the current indicator measure the built environment and the embedded social fabric.Sustainable development requires a functioning ELSS,and to ensure this,complementary indicators that bring environmental aspects to the monitoring of SDG targets are needed.

Phase Stability of the Laves Phase Cr_2Nb in a Two-Phase Cr-Cr_2Nb Alloy

The phase stability of the Laves phase Cr2Nb in a two-phase Cr-Cr2Nb alloy produced by arc-melting was investigated using X-ray diffraction, transmission electron microscopy and selected area electron diffraction. The experimental results indicated that the as-cast ingot was consisted of C15-Cr2Nb and Cr phases; the intermediate C36 and high-temperature C14 modifications of Cr2Nb, reported in literatures, were not detected in this study. These results, combined with a detailed analysis of the actual solidification conditions, revealed that the C14-Cr2Nb was a metastable rather than a stable high-temperature modification. Moreover, a kind of extremely fine lamellar structure was found to be randomly distributed in the eutectic cells, which may be formed by decomposition of the supersaturated C15-Cr2Nb via a discontinuous precipitation reaction.

Basic Hypergeometric Series Quick Access to Identities

The importance of basic hypergeometric series has been widely recognized. For non specialists, it is necessary to have a quick introduction to this classical but flourishing subject. An effort along this direction will be made in the present article.

High-temperature phases of pyrophyllite and their evolutionary characteristics

WITH the increase of heating temperature, phase of pyrophyllite will undergo a series of transformations. Former scholars have done some work in this respect; the temperature spans,however, were normally not more than 1150℃ and no relatively comprehensive results have been reported. Thus, the features of the phases from indoor temperature to melting point (1710℃±) for pyrophyllite and the entire evolutionary process of the phases are uncertain.

A HYBRID METHOD FOR THE SIMULATION OF WAVE SPECTRUM TRANSFORMATION AND BREAKING PHENOMENA ON A SLOPE

In shallow water, during the wave propagation the nonlinear and wave breaking effect must be taken into account. In this peper a simplified hybrid method was proposed, in which a combined frequency and time domain analysis was used. By using authors' method, the process are quite simple and easy to run on a PC computer, but the nonlinear and wave bleaking effect was still been considered. The computed data coincide authors' test results quite well.