Period-conscious Time-series Reconstruction under Local Differential Privacy

Fuente: arXiv
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Main Authors: Wang, Yaxuan, Li, Tianxin, Liang, Enji, Fu, Yue, Wang, Yanran
Format: Preprint
Published: 2026
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author Wang, Yaxuan
Li, Tianxin
Liang, Enji
Fu, Yue
Wang, Yanran
author_facet Wang, Yaxuan
Li, Tianxin
Liang, Enji
Fu, Yue
Wang, Yanran
contents Periodic patterns are fundamental cues in multimedia signals and systems, including repetitive motion in video (e.g., gait cycles), rhythmic and pitch-related structure in audio, and recurring textures in image sequences. When such user-generated streams are collected from edge devices, local differential privacy (LDP) is appealing because it perturbs data before upload; however, the injected noise can corrupt spectral peaks and induce phase drift, making period estimation unreliable and degrading reconstruction quality. We propose \textbf{CPR} (\textit{Cycle and Phase Recovery}), a period-aware reconstruction framework for periodic time series under LDP. CPR performs multi-scale period probing and multi-consensus selection to suppress noise-induced spectral interference, then aggregates perturbed samples at matched within-cycle phase positions to stabilize phase alignment across cycles. To recover the underlying per-phase values, CPR combines EM-based denoising with kernel density estimation, improving robustness under tight privacy budgets. Experiments on two real-world periodic datasets demonstrate that CPR better preserves periodic structure and consistently achieves lower reconstruction error than representative LDP baselines, especially in the low-$ε$ regime.
format Preprint
id arxiv_https___arxiv_org_abs_2605_02724
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Period-conscious Time-series Reconstruction under Local Differential Privacy
Wang, Yaxuan
Li, Tianxin
Liang, Enji
Fu, Yue
Wang, Yanran
Multimedia
Periodic patterns are fundamental cues in multimedia signals and systems, including repetitive motion in video (e.g., gait cycles), rhythmic and pitch-related structure in audio, and recurring textures in image sequences. When such user-generated streams are collected from edge devices, local differential privacy (LDP) is appealing because it perturbs data before upload; however, the injected noise can corrupt spectral peaks and induce phase drift, making period estimation unreliable and degrading reconstruction quality. We propose \textbf{CPR} (\textit{Cycle and Phase Recovery}), a period-aware reconstruction framework for periodic time series under LDP. CPR performs multi-scale period probing and multi-consensus selection to suppress noise-induced spectral interference, then aggregates perturbed samples at matched within-cycle phase positions to stabilize phase alignment across cycles. To recover the underlying per-phase values, CPR combines EM-based denoising with kernel density estimation, improving robustness under tight privacy budgets. Experiments on two real-world periodic datasets demonstrate that CPR better preserves periodic structure and consistently achieves lower reconstruction error than representative LDP baselines, especially in the low-$ε$ regime.
title Period-conscious Time-series Reconstruction under Local Differential Privacy
topic Multimedia
url https://arxiv.org/abs/2605.02724