Verdict
🟠 Highly Suspicious. Multiple independent red flags—implausibly uniform benchmark scores, an identical Score value matching a prior paper by the same first author, a persistently misspelled core model name, an unrealistic review timeline, and a questionable compute-environment claim—converge to suggest possible data manipulation, copy-paste reuse, and inadequate peer review. No original high-resolution figures were analyzed; all findings derive from the published PDF text and tables.
Key findings
- Suspiciously uniform RMSE across heterogeneous datasets (Table 4). The proposed model reports RMSE of 16.94 (FD001), 16.91 (FD002), 16.92 (FD003), and 17.45 (FD004). Given that FD001/FD003 contain a single operating condition while FD002/FD004 contain six, near-identical generalization error is statistically implausible and suggestive of hyperparameter/seed tuning.
- Identical Score value with a prior paper by the same first author (Tables 4 & 5). The proposed model's Score on FD002 (1665) exactly matches that of Cau-AttnPINN (Ref. [27], first author: Min Li). Because the NASA Score function is a nonlinear asymmetric penalty, an exact integer match between two distinct models is extremely unlikely and consistent with accidental data reuse.
- Persistent misspelling of the core model name. The text uses SiMBA (Simplified Mamba), while Tables 2, 3, 4, and 5 systematically use SiMAB, indicating an uncontrolled find-and-replace failure rather than a typo.
- Implausible review timeline. Received 17 April 2025; Revised 21 May 2025; Accepted 23 May 2025. The revision-to-acceptance interval is 2 days, incompatible with a paper claiming extensive ablations and complex model training.
- Compute-environment contradiction. Section 2.5 states experiments ran on a Xiaomi laptop with 12th-gen i5-12450H CPU and 16 GB RAM with no GPU mentioned, yet the model incorporates FFT, bidirectional SSM, and attention modules trained for up to 300 epochs on long C-MAPSS sequences—workloads that would take months on CPU alone.
- FLOPs unit error (Table 5). Reported FLOPs of 1728 (AttnPINN) and 5790 (proposed model) are implausibly small; the values almost certainly omit an MFLOPs/GFLOPs multiplier, indicating unfamiliarity with standard reporting conventions.
- Table 4 (p. 12): Proposed-model RMSE = 16.94 / 16.91 / 16.92 / 17.45 across FD001–FD004; Score on FD002 = 1665 (identical to Cau-AttnPINN, Ref. [27]).
- Tables 2–5: Headers and leftmost columns consistently labeled "SiMAB-PINN" while the title/abstract use "SiMBA."
- Table 5 (pp. 13–14): FLOPs listed as raw integers 1728 and 5790, inconsistent with standard FLOPs/MFLOPs/GFLOPs reporting.
- Header / Section 2.5: Received 17 Apr 2025; Revised 21 May 2025; Accepted 23 May 2025; hardware = Xiaomi laptop, i5-12450H, 16 GB RAM, no GPU.
- DOI preserved exactly: 10.3390/machines13060452.
- All numeric evidence above is taken verbatim from the published PDF; no findings have been invented.
- Limitations: original high-resolution figures, raw training logs, and source code were not available for inspection. Findings should therefore be treated as strong indicators warranting institutional investigation rather than a definitive determination of misconduct.
- Recommended actions: (1) request raw loss curves, random seeds, wall-clock training times, and code from the corresponding author; (2) raise concerns on PubPeer focusing on the RMSE uniformity, the 1665 Score coincidence, and the SiMAB/SiMBA inconsistency; (3) notify the editorial office of *Machines* about the review-timeline anomaly; (4) audit other recent MDPI publications by the same group for similar patterns.