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Zhan-Yi Hu

Publications and source records attributed to Zhan-Yi Hu.

2 recordsLinked to original sources

[Automated recognition of quasars based on adaptive radial basis function neural networks].

Recognizing and certifying quasars through the research on spectra is an important method in the field of astronomy. This paper presents a novel adaptive method for the automated recognition of quasars based on the radial basis function neural networks (RBFN). The proposed method is composed of the following three parts: (1) The feature space is reduced by the PCA (the principal component analysis) on the normalized input spectra; (2) An adaptive RBFN is constructed and trained in this reduced space. At first, the K-means clustering is used for the initialization, then based on the sum of squares errors and a gradient descent optimization technique, the number of neurons in the hidden layer is adaptively increased to improve the recognition performance; (3) The quasar spectra recognition is effectively carried out by the above trained RBFN. The author's proposed adaptive RBFN is shown to be able to not only overcome the difficulty of selecting the number of neurons in hidden layer of the traditional RBFN algorithm, but also increase the stability and accuracy of recognition of quasars. Besides, the proposed method is particularly useful for automatic voluminous spectra processing produced from a large-scale sky survey project, such as our LAMOST, due to its efficiency.

English Abstract↗

[Wavelet transform zero-crossing method for auto-extraction of spectral lines].

Wavelet transform method is used in this paper. The authors firstly studied the properties of spectral lines in the wavelet domain. By introducing the items of up-zero-crossings and down-zero-crossings, the authors concluded that absorption lines and emission lines correspond to different kinds of zero-crossings. Therefore the authors presented a new wavelet transform zero-crossing method for the extraction of spectral lines and the normalization of continuum spectra. The useful spectral lines can be obtained together with the continuum spectra. The extraction of spectral lines in this paper is a direct method, which avoids the errors caused during the process of noise reduction. The experiments both on stars and nearby galaxies show that our method can be used to accurately extract the spectral lines, which is helpful to the computation of characteristic parameters and the automatic classification of spectra based on spectral lines.

Algorithms↗