A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and ca...A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and can suppress additive color or white Gaussian noise. Application of the new feature to classification of MPSK signals, at medium signal-to-noise ratio with specified sample size, results in high probability of correct identification. Finally, computer simulations and comparisons with existing algorithms are given.展开更多
Recently a Hybrid Carrier （HC） scheme based on Weighted-type Fractional Fourier Transform （WFRFT） was proposed and developed, which contains Single Carrier （SC） and Multi-Carrier （MC） synergetie transmission. ...Recently a Hybrid Carrier （HC） scheme based on Weighted-type Fractional Fourier Transform （WFRFT） was proposed and developed, which contains Single Carrier （SC） and Multi-Carrier （MC） synergetie transmission. The wide interest is primarily due to its appealing characteristics, such as the robust performances in different types of selective fading channels and a great deal of potential for secure communications. According to the literatures, the HC signal and SC or MC signal probability distributions are different. In particular, some benefits of this HC scheme are brought by the quasi-Gaussian distribution of WFRFT signals. However, until now researchers have only presented statistic properties through computer simulations, and the accurate expressions of signals are not derived yet. In this paper, we derive the accu- rate and rigorously established closed-form expressions of Probability Density Function （PDF） of WFRFT signal real and imaginary parts with a large number of QPSK subcarriers, and this PDF can describe the behavior of data modulated by WFRFT, avoiding the complex computation for extensive computer simulations. Furthermore, the components of PDF expression are described and analyzed, and it is revealed that the tendency of signal quasi-Gaussian changes with the increasing of the parameter a （a in （0,1]）. To validate the analytical results, extensive simulations have been conducted, showing a very good match between the analytical results and the real situations. The contribution of this paper may be useful to deduce the closed form expressions of Bit Error Ratio （BER）, the Complementary Cumulative Distribution Function （CCDF） of Peak to Average Power Ratio （PAPR）, and other analytical studies which adopt the PDF.展开更多
This paper presents a brief analysis of the frequency and cumulative distributions of Americans＇ annual household income. In addition, a thorough discussion of the correlations between average income and some key dem...This paper presents a brief analysis of the frequency and cumulative distributions of Americans＇ annual household income. In addition, a thorough discussion of the correlations between average income and some key demographic variables are included. The data come from the 2004 Survey of Consumer Finances. Utilizing the Survey a new, extraordinarily close, power law, relationship between current annual household income and accumulated financial assets is demonstrated. Another startling result is that the dependence of mean annual income on portfolio composition has nearly perfect power law dependence too. As money has scale, and power laws do not, this makes no sense.展开更多
In the study, E. sibiricus L. cv. chuancao No. 2 was allocated to plots in a randomized block design with five row gradients （30, 45, 60, 75 and 90 cm）. At the flowering stage, the root, stem, leaf and inflorescence...In the study, E. sibiricus L. cv. chuancao No. 2 was allocated to plots in a randomized block design with five row gradients （30, 45, 60, 75 and 90 cm）. At the flowering stage, the root, stem, leaf and inflorescence of population, as well as the quantitative traits of components, biomass structure, accumulation and distribution proportion of energy were measured and analyzed. For different row spacings, there are highly significant differences between total tillers and ratio of fertile tillers per square meter and significant differences among the eustipes length, eustipes number and natural height of each tiller; but there are no significant differences among the leaf length, leaf width and leaf number of each tiller. A significant difference is found between the depth and distribution range of root, inflorescence stalk, and ear number of fertile tillers, and the biomass of leaf, stem, root and inflorescence. The influenced order is stem 〉 leave 〉 root 〉 inflorescence. No significant influence is found among the energy values of single leaf, stem, root and inflorescence; but a significant influence is found among the energy accumulation of the leaf, stem, root and inflorescence with the effect degree being stem 〉 leaf 〉 inflorescence 〉 root. Significant differences are also found among the energy distribution of each component with the order of leaf〉 stem 〉 inflorescence 〉 root.展开更多
文摘A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and can suppress additive color or white Gaussian noise. Application of the new feature to classification of MPSK signals, at medium signal-to-noise ratio with specified sample size, results in high probability of correct identification. Finally, computer simulations and comparisons with existing algorithms are given.
基金supported by the National Natural Science Foundation General Program of China(No.61201146)the National Basic Research Program of China(2013CB329003)the Fundamental Research Funds for the Central Universities(HIT.NSRIF.2015022)
文摘Recently a Hybrid Carrier （HC） scheme based on Weighted-type Fractional Fourier Transform （WFRFT） was proposed and developed, which contains Single Carrier （SC） and Multi-Carrier （MC） synergetie transmission. The wide interest is primarily due to its appealing characteristics, such as the robust performances in different types of selective fading channels and a great deal of potential for secure communications. According to the literatures, the HC signal and SC or MC signal probability distributions are different. In particular, some benefits of this HC scheme are brought by the quasi-Gaussian distribution of WFRFT signals. However, until now researchers have only presented statistic properties through computer simulations, and the accurate expressions of signals are not derived yet. In this paper, we derive the accu- rate and rigorously established closed-form expressions of Probability Density Function （PDF） of WFRFT signal real and imaginary parts with a large number of QPSK subcarriers, and this PDF can describe the behavior of data modulated by WFRFT, avoiding the complex computation for extensive computer simulations. Furthermore, the components of PDF expression are described and analyzed, and it is revealed that the tendency of signal quasi-Gaussian changes with the increasing of the parameter a （a in （0,1]）. To validate the analytical results, extensive simulations have been conducted, showing a very good match between the analytical results and the real situations. The contribution of this paper may be useful to deduce the closed form expressions of Bit Error Ratio （BER）, the Complementary Cumulative Distribution Function （CCDF） of Peak to Average Power Ratio （PAPR）, and other analytical studies which adopt the PDF.
文摘This paper presents a brief analysis of the frequency and cumulative distributions of Americans＇ annual household income. In addition, a thorough discussion of the correlations between average income and some key demographic variables are included. The data come from the 2004 Survey of Consumer Finances. Utilizing the Survey a new, extraordinarily close, power law, relationship between current annual household income and accumulated financial assets is demonstrated. Another startling result is that the dependence of mean annual income on portfolio composition has nearly perfect power law dependence too. As money has scale, and power laws do not, this makes no sense.
文摘In the study, E. sibiricus L. cv. chuancao No. 2 was allocated to plots in a randomized block design with five row gradients （30, 45, 60, 75 and 90 cm）. At the flowering stage, the root, stem, leaf and inflorescence of population, as well as the quantitative traits of components, biomass structure, accumulation and distribution proportion of energy were measured and analyzed. For different row spacings, there are highly significant differences between total tillers and ratio of fertile tillers per square meter and significant differences among the eustipes length, eustipes number and natural height of each tiller; but there are no significant differences among the leaf length, leaf width and leaf number of each tiller. A significant difference is found between the depth and distribution range of root, inflorescence stalk, and ear number of fertile tillers, and the biomass of leaf, stem, root and inflorescence. The influenced order is stem 〉 leave 〉 root 〉 inflorescence. No significant influence is found among the energy values of single leaf, stem, root and inflorescence; but a significant influence is found among the energy accumulation of the leaf, stem, root and inflorescence with the effect degree being stem 〉 leaf 〉 inflorescence 〉 root. Significant differences are also found among the energy distribution of each component with the order of leaf〉 stem 〉 inflorescence 〉 root.
