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Shuo Xiang

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3 papers

2 author rows

AIJ Journal 2015 Journal Article

Efficient nonconvex sparse group feature selection via continuous and discrete optimization

Shuo Xiang
Xiaotong Shen
Jieping Ye

Sparse feature selection has proven to be effective in analyzing high-dimensional data. While promising, most existing works apply convex methods, which may be suboptimal in terms of the accuracy of feature selection and parameter estimation. In this paper, we consider both continuous and discrete nonconvex paradigms to sparse group feature selection, which are motivated by applications that require identifying the underlying group structure and performing feature selection simultaneously. The main contribution of this article is twofold: (1) computationally, we develop efficient optimization algorithms for both continuous and discrete formulations, of which the key step is a projection with two coupled constraints; (2) statistically, we show that the proposed continuous model reconstructs the oracle estimator. Therefore, consistent feature selection and parameter estimation are achieved simultaneously. Numerical results on synthetic and real-world data suggest that the proposed nonconvex methods compare favorably against their competitors, thus achieving desired goal of delivering high performance.

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YNIMG Journal 2014 Journal Article

Bi-level multi-source learning for heterogeneous block-wise missing data

Shuo Xiang
Lei Yuan
Wei Fan
Yalin Wang
Paul M. Thompson
Jieping Ye

Bio-imaging technologies allow scientists to collect large amounts of high-dimensional data from multiple heterogeneous sources for many biomedical applications. In the study of Alzheimer's Disease (AD), neuroimaging data, gene/protein expression data, etc. , are often analyzed together to improve predictive power. Joint learning from multiple complementary data sources is advantageous, but feature-pruning and data source selection are critical to learn interpretable models from high-dimensional data. Often, the data collected has block-wise missing entries. In the Alzheimer's Disease Neuroimaging Initiative (ADNI), most subjects have MRI and genetic information, but only half have cerebrospinal fluid (CSF) measures, a different half has FDG-PET; only some have proteomic data. Here we propose how to effectively integrate information from multiple heterogeneous data sources when data is block-wise missing. We present a unified “bi-level” learning model for complete multi-source data, and extend it to incomplete data. Our major contributions are: (1) our proposed models unify feature-level and source-level analysis, including several existing feature learning approaches as special cases; (2) the model for incomplete data avoids imputing missing data and offers superior performance; it generalizes to other applications with block-wise missing data sources; (3) we present efficient optimization algorithms for modeling complete and incomplete data. We comprehensively evaluate the proposed models including all ADNI subjects with at least one of four data types at baseline: MRI, FDG-PET, CSF and proteomics. Our proposed models compare favorably with existing approaches.

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ICML Conference 2013 Conference Paper

Efficient Sparse Group Feature Selection via Nonconvex Optimization

Shuo Xiang
Xiaoshen Tong
Jieping Ye

Sparse feature selection has been demonstrated to be effective in handling high-dimensional data. While promising, most of the existing works use convex methods, which may be suboptimal in terms of the accuracy of feature selection and parameter estimation. In this paper, we expand a nonconvex paradigm to sparse group feature selection, which is motivated by applications that require identifying the underlying group structure and performing feature selection simultaneously. The main contributions of this article are twofold: (1) computationally, we introduce a nonconvex sparse group feature selection model and present an efficient optimization algorithm, of which the key step is a projection with two coupled constraints; (2) statistically, we show that the proposed model can reconstruct the oracle estimator. Therefore, consistent feature selection and parameter estimation can be achieved. Numerical results on synthetic and real-world data suggest that the proposed nonconvex method compares favorably against its competitors, thus achieving desired goal of delivering high performance.

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