Statistics of order 2 (variance, auto and cross-correlation functions, auto and cross-power spectra) and 3 (skewness, auto and cross-bicorrelation functions, auto and cross-bispectra) are used to analyze the wave-part...Statistics of order 2 (variance, auto and cross-correlation functions, auto and cross-power spectra) and 3 (skewness, auto and cross-bicorrelation functions, auto and cross-bispectra) are used to analyze the wave-particle interaction in space plasmas. The signals considered here are medium scale electron density irregularities and ELF/ULF electrostatic turbulence. Nonlinearities are mainly observed in the ELF range. They are independently pointed out in time series associated with fluctuations in electronic density and in time series associated with the measurement of one electric field component. Peaks in cross-bicorrelation function and in mutual information clearly show that, in well delimited frequency bands, the wave-particle interactions are nonlinear above a certain level of fluctuations. The way the energy is transferred within the frequencies of density fluctuations is indicated by a bi-spectra analysis.展开更多
This paper addresses the problem of adaptively estimating the consistent parameters for non Gaussian nonminimum MA processes with symmetric PDF using the fourth order cumulant of the underlying processes. The process...This paper addresses the problem of adaptively estimating the consistent parameters for non Gaussian nonminimum MA processes with symmetric PDF using the fourth order cumulant of the underlying processes. The processes may be corrupted by additive noise.展开更多
【目的】随着深部资源勘探开发的重要性不断提高,对高精度地震勘探提出了新要求。针对具有强各向异性的含煤地层,传统基于各向同性的资料处理方法不再适用。【方法】提出一种基于水平横向各向同性介质(Transverse Isotropy Medium with ...【目的】随着深部资源勘探开发的重要性不断提高,对高精度地震勘探提出了新要求。针对具有强各向异性的含煤地层,传统基于各向同性的资料处理方法不再适用。【方法】提出一种基于水平横向各向同性介质(Transverse Isotropy Medium with Vertical Symmetry Axis,VTI)和方位各向异性介质(Transverse Isotropy with Horizontal Axis of Symmetry,HTI)联合处理的地震数据处理方法。首先,针对含煤地层沉积特征,分析VTI介质特点,采用高阶动校正处理,可以有效消除各向异性在大偏移距数据中引起的同相轴弯曲,保证共反射点远近道能达到同相,提高数据叠加成像质量。其次,针对构造裂隙发育特征,立足于HTI介质的方位各向异性分析,采用OVT域处理方法,通过建立方位各向异性参数场去除不同方位角差异对数据的影响。联合应用上述2种处理方法,通过制定合理的处理流程,优选关键参数,搭建一套实用的、适合目标地层的各向异性处理校正方法,解决含煤地层在复杂条件下的速度分析、叠加等问题,从而提高煤系地震数据的分辨率和解释精度。【结果和结论】实际应用结果表明,新方法获得的地震数据主频更高、频带更宽,在小构造特征识别和古地理环境刻画方面更具优势,为精细地质解释提供了有力支撑。同时也强调了对含煤地层进行各向异性处理的必要性,推动各向异性处理技术的在宽方位地震勘探中的应用。展开更多
In this paper, a labelled transition semantics for higher-order processcalculi is studied. The labelled transition semantics is relatively clean and simple, andcorresponding bisimulation equivalence can be easily form...In this paper, a labelled transition semantics for higher-order processcalculi is studied. The labelled transition semantics is relatively clean and simple, andcorresponding bisimulation equivalence can be easily formulated based on it. And the congruenceproperties of the bisimulation equivalence can be proved easily. To show the correspondence betweenthe proposed semantics and the well-established ones, the bisimulation is characterized as a versionof barbed equivalence and a version of context bisimulation.展开更多
In this paper we construct models obtained by suitably combining Brownian motions and telegraphs in such a way that their transition functions satisfy higher-order parabolic or hyperbolic equations of different types....In this paper we construct models obtained by suitably combining Brownian motions and telegraphs in such a way that their transition functions satisfy higher-order parabolic or hyperbolic equations of different types. Equations with time-varying coefficients are also derived by considering processes endowed either with drift or with suitable modifications of their structure. Finally the distribution of the maximum of the iterated Brownian motion (along with some other properties) is presented.展开更多
Modal logic characterization in a higher-order setting is usually not a trivial task because higher-order process-passing is quite different from first-order name-passing. We study the logical characterization of high...Modal logic characterization in a higher-order setting is usually not a trivial task because higher-order process-passing is quite different from first-order name-passing. We study the logical characterization of higherorder processes constrained by linearity. Linearity respects resource-sensitiveness and does not allow processes to duplicate themselves arbitrarily. We provide a modal logic that characterizes linear higher-order processes,particularly the bisimulation called local bisimulation over them. More importantly, the logic has modalities for higher-order actions downscaled to resembling first-order ones in Hennessy-Milner logic, based on a formulation exploiting the linearity of processes.展开更多
高频大地电磁法(HMT)信号在20 k Hz^100 k Hz频率范围内易受人文噪声干扰,电磁信号强度弱,数据误差大。本文提出采用高阶谱分析重构高频大地电磁非最小相位信号,进而有效抑制随机高斯噪声、提高信噪比。通过数值模拟信号和实测数据处理...高频大地电磁法(HMT)信号在20 k Hz^100 k Hz频率范围内易受人文噪声干扰,电磁信号强度弱,数据误差大。本文提出采用高阶谱分析重构高频大地电磁非最小相位信号,进而有效抑制随机高斯噪声、提高信噪比。通过数值模拟信号和实测数据处理,证明该方法能有效压制噪声,在提取实际地质信息方面优于传统方法。展开更多
文摘Statistics of order 2 (variance, auto and cross-correlation functions, auto and cross-power spectra) and 3 (skewness, auto and cross-bicorrelation functions, auto and cross-bispectra) are used to analyze the wave-particle interaction in space plasmas. The signals considered here are medium scale electron density irregularities and ELF/ULF electrostatic turbulence. Nonlinearities are mainly observed in the ELF range. They are independently pointed out in time series associated with fluctuations in electronic density and in time series associated with the measurement of one electric field component. Peaks in cross-bicorrelation function and in mutual information clearly show that, in well delimited frequency bands, the wave-particle interactions are nonlinear above a certain level of fluctuations. The way the energy is transferred within the frequencies of density fluctuations is indicated by a bi-spectra analysis.
文摘This paper addresses the problem of adaptively estimating the consistent parameters for non Gaussian nonminimum MA processes with symmetric PDF using the fourth order cumulant of the underlying processes. The processes may be corrupted by additive noise.
文摘【目的】随着深部资源勘探开发的重要性不断提高,对高精度地震勘探提出了新要求。针对具有强各向异性的含煤地层,传统基于各向同性的资料处理方法不再适用。【方法】提出一种基于水平横向各向同性介质(Transverse Isotropy Medium with Vertical Symmetry Axis,VTI)和方位各向异性介质(Transverse Isotropy with Horizontal Axis of Symmetry,HTI)联合处理的地震数据处理方法。首先,针对含煤地层沉积特征,分析VTI介质特点,采用高阶动校正处理,可以有效消除各向异性在大偏移距数据中引起的同相轴弯曲,保证共反射点远近道能达到同相,提高数据叠加成像质量。其次,针对构造裂隙发育特征,立足于HTI介质的方位各向异性分析,采用OVT域处理方法,通过建立方位各向异性参数场去除不同方位角差异对数据的影响。联合应用上述2种处理方法,通过制定合理的处理流程,优选关键参数,搭建一套实用的、适合目标地层的各向异性处理校正方法,解决含煤地层在复杂条件下的速度分析、叠加等问题,从而提高煤系地震数据的分辨率和解释精度。【结果和结论】实际应用结果表明,新方法获得的地震数据主频更高、频带更宽,在小构造特征识别和古地理环境刻画方面更具优势,为精细地质解释提供了有力支撑。同时也强调了对含煤地层进行各向异性处理的必要性,推动各向异性处理技术的在宽方位地震勘探中的应用。
文摘In this paper, a labelled transition semantics for higher-order processcalculi is studied. The labelled transition semantics is relatively clean and simple, andcorresponding bisimulation equivalence can be easily formulated based on it. And the congruenceproperties of the bisimulation equivalence can be proved easily. To show the correspondence betweenthe proposed semantics and the well-established ones, the bisimulation is characterized as a versionof barbed equivalence and a version of context bisimulation.
基金This work is partially supported by the Natural Science Foundation of Guangdong ProvinceNational Natural Science Foundation of China grant No. 19501026the Alexander yon Humbodlt Foundation
文摘In this paper we construct models obtained by suitably combining Brownian motions and telegraphs in such a way that their transition functions satisfy higher-order parabolic or hyperbolic equations of different types. Equations with time-varying coefficients are also derived by considering processes endowed either with drift or with suitable modifications of their structure. Finally the distribution of the maximum of the iterated Brownian motion (along with some other properties) is presented.
基金the National Natural Science Foundation of China(Nos.61202023,61261130589 and61173048)the PACE Project(No.12IS02001)the Specialized Research Fund for the Doctoral Program of Higher Edueation of China(No.20120073120031)
文摘Modal logic characterization in a higher-order setting is usually not a trivial task because higher-order process-passing is quite different from first-order name-passing. We study the logical characterization of higherorder processes constrained by linearity. Linearity respects resource-sensitiveness and does not allow processes to duplicate themselves arbitrarily. We provide a modal logic that characterizes linear higher-order processes,particularly the bisimulation called local bisimulation over them. More importantly, the logic has modalities for higher-order actions downscaled to resembling first-order ones in Hennessy-Milner logic, based on a formulation exploiting the linearity of processes.
文摘高频大地电磁法(HMT)信号在20 k Hz^100 k Hz频率范围内易受人文噪声干扰,电磁信号强度弱,数据误差大。本文提出采用高阶谱分析重构高频大地电磁非最小相位信号,进而有效抑制随机高斯噪声、提高信噪比。通过数值模拟信号和实测数据处理,证明该方法能有效压制噪声,在提取实际地质信息方面优于传统方法。
