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Xiaxin Li

Publications and source records attributed to Xiaxin Li.

3 recordsLinked to original sources

Support Recovery in One-bit Compressed Sensing with Near-Optimal Measurements and Sublinear Time

One-bit compressed sensing (1bCS) addresses the recovery of sparse signals from highly quantized measurements, retaining only the sign of each linear measurement. From a data compression perspective, the one-bit measurements form a compact binary representation of sparse signals. The support recovery problem seeks to recover the support of an unknown signal $x\in\mathbb{R}^n$, $\mathrm{supp}(x)$, from $y=\mathrm{sgn}(Ax)$, where $A\in\mathbb{R}^{m\times n}$ is the measurement matrix and $|\mathrm{supp}(x)|\le k\ll n$. Existing methods seek to minimize the number of measurements but often incur $Ω(n)$ decoding complexity, limiting their applicability to large-scale problems. We propose new 1bCS schemes that achieve sublinear decoding complexity while maintaining near-optimal measurement bounds. For universal support recovery, our framework provides: (i) exact recovery with $m=O(k^2\log(n/k)\log n)$ measurements and decoding complexity $D=O(km)$, and (ii) $ε$-approximate recovery with $m=O(kε^{-1}\log(n/k)\log n)$ and $D=O(ε^{-1}m)$. For probabilistic exact recovery, we design a scheme with $m=O(k\log k\log n)$ and $D=O(m)$, achieving vanishing error probability. Our schemes leverage ideas from group testing to achieve near-optimal support compression with substantially reduced decoding complexity.

cs.IT

The Noisy Quantitative Group Testing Problem

In this paper, we study the problem of quantitative group testing (QGT) and analyze the performance of three models: the noiseless model, the additive Gaussian noise model, and the noisy Z-channel model. For each model, we analyze two algorithmic approaches: a linear estimator based on correlation scores, and a least squares estimator (LSE). We derive upper bounds on the number of tests required for exact recovery with vanishing error probability, and complement these results with information-theoretic lower bounds. In the additive Gaussian noise setting, our lower and upper bounds match in order.

cs.IT

Noisy Nonadaptive Group Testing with Binary Splitting: New Test Design and Improvement on Price-Scarlett-Tan's Scheme

In Group Testing, the objective is to identify $K$ defective items out of $N$, $K\ll N$, by testing pools of items together and using the least amount of tests possible. Recently, a fast decoding method based on binary splitting (Price and Scarlett, 2020) has been proposed that simultaneously achieve optimal number of tests and decoding complexity for Non-Adaptive Probabilistic Group Testing (NAPGT). However, the method works only when the test results are noiseless. In this paper, we further study the binary splitting method and propose (1) A NAPGT scheme that generalizes the original binary splitting method from the noiseless case into tests with $ρ$ proportion of false positives (the $ρ$-False Positive Channel), where $ρ$ is a constant, with asymptotically-optimal number of tests and decoding complexity, i.e. $\mathcal{O}(K\log N)$, and (2) A NAPGT scheme in the presence of both false positives and false negatives in test outcomes, improving and generalizing the work of Price, Scarlett and Tan~\cite{price2023fast} in two ways: First, under $ρ$-proportion of test results flipped ($ρ$-Binary Symmetric Channel) and within the general sublinear regime $K=Θ(N^α)$ where $0<α<1$, our algorithm has a decoding complexity of $\mathcal{O}(ε^{-2}K^{1+ε})$ where $ε>0$ is a constant parameter. Second, when the false negative flipping probability $ρ'$ satisfies $ρ'=\mathcal{O}(K^{-ε})$ and the false positive flipping probability $ρ$ is a constant, we can simultaneously achieve $\mathcal{O}(ε^{-1}K\log N)$ for both the number of tests and the decoding complexity. It remains open to achieve these optimals under the general BSC.

cs.IT