Recently, Open Source Software （OSS） is so widely used not only by companies for development but also by common users instead of commercial software. However, the number of OSS is vast, and its quality varies from l...Recently, Open Source Software （OSS） is so widely used not only by companies for development but also by common users instead of commercial software. However, the number of OSS is vast, and its quality varies from low to high. So how people can evaluate OSS and ensta-e that it is reliable for use becomes necessary. This paper proposes a set of reliability evaluation metrics considering the states of OSS selected in the early stage. Understandability, Fault tolerance ＆ Recoverability and Community Matmrity as sub-attributes of reliability are defined, and then several evaluation criteria for each of them are identified. A process of reliability evaluation in our study is proposed. For application, we select four OSS projects and evaluate them with our metrics. As a result of compadrison with other evaluation model for OSS, our research presents an easy, effective and trustworthy way for selecting a reliable OSS.展开更多
The correlation analysis of sea clutter data in a complex domain is conducted in this study. Specific to X-band sea clutter, the statistical characteristics of the complex correlation, particularly the phase character...The correlation analysis of sea clutter data in a complex domain is conducted in this study. Specific to X-band sea clutter, the statistical characteristics of the complex correlation, particularly the phase characteristics which are closely related to the phase difference of the sea clutter and the Doppler properties, are analyzed in detail based on the experimental data, recorded by the Mc Master University IPIX radar in 1993. That the phase term of the complex correlation presents linear change means that there exists the linearity of phase differences between different time intervals in the X-band sea clutter. This investigation explores the regularities about the effect of wind on the complex correlation with similar patterns for different polarization modes. The regularities indicate that the wind direction can be inferred from the distribution pattern of the complex correlation. Moreover, a model describing the relationships between the statistics of the complex correlation and wind parameters is proposed. The application for target detection based on the differences of characteristics of complex correlations between the sea clutter and the target are also investigated and the proposed features have been confirmed. The principle of the method is fundamental for broader future applications.展开更多
Let eλ（x） be a Neumann eigenfunction with respect to the positive Laplacian λ on a compact Riemannian manifold M with boundary such that A eλ = λ2eλ in the interior of M and the normal derivative of ex vanishes...Let eλ（x） be a Neumann eigenfunction with respect to the positive Laplacian λ on a compact Riemannian manifold M with boundary such that A eλ = λ2eλ in the interior of M and the normal derivative of ex vanishes on the boundary of M. Let xλ be the unit band spectral projection operator associated with the Neumann Laplacian and f be a square integrable function on M. The authors show the following gradient estimate展开更多
文摘Recently, Open Source Software （OSS） is so widely used not only by companies for development but also by common users instead of commercial software. However, the number of OSS is vast, and its quality varies from low to high. So how people can evaluate OSS and ensta-e that it is reliable for use becomes necessary. This paper proposes a set of reliability evaluation metrics considering the states of OSS selected in the early stage. Understandability, Fault tolerance ＆ Recoverability and Community Matmrity as sub-attributes of reliability are defined, and then several evaluation criteria for each of them are identified. A process of reliability evaluation in our study is proposed. For application, we select four OSS projects and evaluate them with our metrics. As a result of compadrison with other evaluation model for OSS, our research presents an easy, effective and trustworthy way for selecting a reliable OSS.
基金supported by the National Natural Science Foundation of China (61271406)
文摘The correlation analysis of sea clutter data in a complex domain is conducted in this study. Specific to X-band sea clutter, the statistical characteristics of the complex correlation, particularly the phase characteristics which are closely related to the phase difference of the sea clutter and the Doppler properties, are analyzed in detail based on the experimental data, recorded by the Mc Master University IPIX radar in 1993. That the phase term of the complex correlation presents linear change means that there exists the linearity of phase differences between different time intervals in the X-band sea clutter. This investigation explores the regularities about the effect of wind on the complex correlation with similar patterns for different polarization modes. The regularities indicate that the wind direction can be inferred from the distribution pattern of the complex correlation. Moreover, a model describing the relationships between the statistics of the complex correlation and wind parameters is proposed. The application for target detection based on the differences of characteristics of complex correlations between the sea clutter and the target are also investigated and the proposed features have been confirmed. The principle of the method is fundamental for broader future applications.
基金supported by the National Natural Science Foundation of China(Nos.10971104,11271343,11101387)the Anhui Provincial Natural Science Foundation(No.1208085MA01)the Fundamental Research Funds for the Central Universities(Nos.WK0010000020,WK0010000023,WK3470000003)
文摘Let eλ（x） be a Neumann eigenfunction with respect to the positive Laplacian λ on a compact Riemannian manifold M with boundary such that A eλ = λ2eλ in the interior of M and the normal derivative of ex vanishes on the boundary of M. Let xλ be the unit band spectral projection operator associated with the Neumann Laplacian and f be a square integrable function on M. The authors show the following gradient estimate
