REVIEW 4 major objections 6 minor 37 references
FE-MCFormer: a novel time-frequency interpretable architecture for machinery fault diagnosis under strong noise environments
T0 review · 4 major / 6 minor · reviewed 2026-08-15 · deepseek-v4-flash
Pith's one-line read FE-MCFormer proposes a learnable Fourier reconstruction layer plus multiscale time-frequency fusion to keep rotating-machinery fault diagnosis accurate and interpretable at signal-to-noise ratios down to -10 dB, outperforming seven…
desk verdict Solid engineering paper with a load-bearing metric problem: Eq. (19) defines accuracy as precision, so the headline accuracy tables are unverifiable. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The load-bearing mechanism is FAREL (Fourier adaptive reconstruction embedding layer), a learnable spectral gate: after a $1\times 63$ convolution, the signal is transformed with the discrete Fourier transform, multiplied element-wise by a learnable complex weight $W$, transformed back with the inverse DFT, and added back to the original feature map with a scaling factor $\gamma$. This makes the network learn which frequency bins carry fault information and which carry noise. The same Fourier adaptive reconstruction appears inside the time-frequency fusion network (TFFN), and the multiscale time-frequency fusion (MSTFF) module's multiscale convolutional attention layer (MSCAL) supplies the local time-domain branch with $1\times 3$ and $1\times 5$ kernels, softmax attention, and residual connections; distillation layers halve the time dimension to widen the receptive field.
What would settle it
Recompute every reported result with the standard accuracy formula $\frac{TP+TN}{TP+TN+FP+FN}$ on the same test splits; if the corrected percentages fall substantially or the method no longer leads at low SNR, the central claim fails. A second, complementary test is to run FE-MCFormer on field vibration data with colored or non-stationary noise; if its margin over baselines disappears, the robustness claim is an artifact of white-noise injection.
Extended reading notes
Core claim
FE-MCFormer establishes that a transformer for machinery fault diagnosis does not need conventional multi-head self-attention to excel under heavy noise. The paper's central discovery is that replacing multi-head self-attention with a multiscale convolutional attention layer and inserting Fourier adaptive reconstruction at the embedding and feed-forward stages lets the network learn which frequency components carry fault information: it attenuates noise-dominated bins, preserves fault harmonics, and concentrates attention on impulsive fault regions. The evidence is the reported accuracy at SNR values from -2 to -10 dB on the bearing and gearbox datasets, plus feature-quality metrics and t-SNE and heatmap visualizations showing tighter clustering and more focused attention than baselines. On the real compressor data, the method reports 96.89% mean accuracy despite only 240 samples per class.
Load-bearing premise
The headline percentages are only as strong as the accuracy metric in Eq. (19), which defines Acc as $TP/(TP+FP)$ — precision, not accuracy — and the noise-robustness results are only as strong as the assumption that Gaussian white noise added via Eq. (20) represents real industrial strong noise.
Editorial extensions
If this is right
- If the reported results hold, FE-MCFormer is the best among the compared methods on all three datasets at every SNR from -2 dB to -10 dB, with the largest gains at the lowest signal-to-noise ratios.
- FAREL is claimed to be a general plug-and-play component: adding it to a WDCNN baseline raised mean accuracy by 4.31 to 9.92 percentage points across SNR levels on the bearing dataset.
- The method maintains usable accuracy in extreme noise, for example 72.99% mean accuracy on the bearing dataset at -10 dB SNR, where the strongest transformer baseline reaches 60.65%.
- On the small-sample real compressor dataset, FE-MCFormer reports 96.89% mean accuracy, suggesting the architecture transfers to field data with limited training samples.
- The interpretability claims imply the model's attention and reconstructed spectra can be read as physical evidence: noise bands are attenuated and harmonics at $1\times f$, $2\times f$, and $3\times f$ are enhanced.
Reading between the lines
- Although the paper only demonstrates FAREL as a plug-in for WDCNN, the same mechanism could be inserted into other CNN or transformer backbones; a systematic study across architectures would establish how general the improvement is.
- The learned frequency mask that FAREL produces could be extracted and applied as a standalone pre-processing denoiser before any classifier, which the paper hints at but does not formalize.
- Because all noise injections are Gaussian white noise, a direct test would add colored or non-stationary noise from variable-speed machinery; the 'strong noise' claim is only shown for white-noise contamination.
Signed reviews
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes FE-MCFormer, a transformer-inspired architecture for rotating machinery fault diagnosis under strong noise. It introduces a Fourier Adaptive Reconstruction Embedding Layer (FAREL) that performs learnable spectral filtering, and a Multiscale Time-Frequency Fusion (MSTFF) module combining multiscale convolutional attention with frequency-domain reconstruction. The method is evaluated on three datasets (PU bearing, SEU gearbox, and a real-world centrifugal compressor dataset) with Gaussian white noise added at SNR levels from -2 to -10 dB, compared against seven deep learning baselines, and is supported by ablation studies and interpretability visualizations. The reported results indicate consistent accuracy improvements, particularly from the FAREL component, which is also presented as a plug-and-play enhancement for existing CNN models.
Significance. If the reported results are accurate, the paper makes a useful empirical contribution: a novel architecture that improves noise robustness, and a plug-and-play component (FAREL) that consistently improves existing models such as WDCNN. The experiments are extensive, include a real-world dataset, and the architecture is described in sufficient detail for reproduction. The inclusion of the FAREL ablation with WDCNN-FAREL provides a falsifiable claim about the component's generality. However, the central metric-definition issue and the lack of variance reporting currently prevent full verification of the quantitative claims, and the interpretability evidence is post-hoc rather than independent verification of physical mechanisms.
major comments (4)
- [Section 3.1, Eq. (19)] The evaluation metric is defined as Acc = TP/(TP+FP) × 100%, which is precision, not accuracy. All reported mean-acc and max-acc values in Tables 3, 4, 6, and 9, as well as the abstract headline numbers, depend on this definition. In the multi-class settings of this paper (18 classes in Case 1, 5 classes in Cases 2 and 3), accuracy should be computed as (TP+TN)/(TP+TN+FP+FN). Unless the implementation actually used a correct accuracy formula, the claimed superiority over the seven baselines is unverified. Please correct the definition or provide code, per-class confusion matrices, or TP/FP counts to resolve this discrepancy.
- [Section 3.1, experimental settings] Only the mean and maximum over five repeated runs are reported, with no standard deviation, confidence intervals, or significance tests. Several comparative margins are small at high SNR (e.g., Table 3, SNR=-2: FE-MCFormer 99.11% vs. Li-convformer 97.53%; Table 6, SNR=-8: 98.52% vs. 97.86%). Without variance information or significance testing, the claim of consistent superiority is not statistically supported. Please report per-run results, error bars, or perform statistical tests for the key comparisons.
- [Section 3.3.2, after Table 6] The text states that 'FE-MCFormer achieves diagnosis accuracies of 100%, 100%, 94.93%, 98.83%, and 95.51% in five trials,' but Table 6 lists mean accuracies of 95.51%, 98.52%, 99.79%, 100%, and 100% for SNR values from -10 dB to -2 dB. The five numbers in the text do not match the table entries, creating an internal inconsistency in the reporting of the main Case 2 result.
- [Section 3.2.3, Table 4] The claim that 'smaller scaling factors γ achieve the better performance across all noise levels' is contradicted by Table 4, where FE-MCFormer-0.2 (73.58%) and FE-MCFormer-0.3 (86.41%) outperform FE-MCFormer-0.1 (72.99% and 86.31%) at SNR=-10 and SNR=-8, respectively. The text acknowledges these exceptions but still draws the opposite conclusion, so the sensitivity analysis interpretation needs to be reconciled with the reported data.
minor comments (6)
- [Section 2.1, after Eq. (5)] The sentence fragment 'various tasks and data properties' appears without a verb; please rewrite the sentence.
- [Sections 2.2.1 and 3.2.3] The abbreviation 'MSA' is used to refer to the multiscale attention mechanism, while the Introduction uses 'MHSA' for multi-head self-attention; please disambiguate these terms.
- [Table 7] The table header contains formatting artifacts ('Methodsssssss', '𝐽1ssssss𝐽2'); please clean up the table formatting.
- [Section 3.4.1] The phrase 'the 7200 and 3300 eddy current probes' should specify what these numbers refer to (e.g., model numbers or measurement ranges).
- [References] Reference [3] has a publication year of 2026, which is in the future; please verify the citation details.
- [Abstract and Section 3.2.2] The abstract claims 'stable and interpretable diagnostic performance ... down to -10 dB SNR', but in Case 1 the mean accuracy at -10 dB is 72.99%, which is substantially lower than at higher SNR; please clarify what is meant by 'stable'.
Circularity Check
No significant circularity; the central claims rest on held-out empirical tests, with Eq. (19) a correctness risk rather than a derivational circle.
full rationale
The claimed derivations in this paper are architectural and empirical, not first-principles predictions. FAREL and TFFN are defined by Eqs. (1)-(16) as convolutional/DFT operations with learnable weights W; no statement in the paper asserts that these equations produce the reported accuracies by construction. The accuracy numbers in Tables 3, 6, and 9 are held-out test results on external benchmarks (PU bearing, SEU gearbox, real compressor) with fixed train/test splits, and the WDCNN-FAREL comparison is an independent empirical ablation on the same held-out protocol. There is no load-bearing self-citation chain: Refs. [15] and [16] overlap with the authors but are cited only as background examples of multiscale attention networks, not as justification of the proposed method or as uniqueness theorems. The interpretability figures use the trained model's own reconstructions and attention maps; that is post-hoc introspection, not a derivation that assumes what it claims to show. One serious correctness risk, but not a circularity, is Eq. (19), which literally defines 'accuracy' as TP/(TP+FP), i.e., precision. If the implementation followed Eq. (19), then all 'mean-acc' and 'max-acc' values are precision values and the headline accuracy claims are mislabeled; this cannot be resolved without code or corrected metrics. This is a definitional and verification flaw in the evaluation, not a case of the model's output being equivalent to its input by construction. Hence the circularity score is 0.
Assumptions & free parameters
free parameters (3)
- gamma (scaling factor) =
0.1
- Architecture hyperparameters (kernel sizes, channel widths, number of MSTFF blocks) =
63-tap embedding kernel, 1x3 and 1x5 kernels, 4 blocks, channels 32/64/128/256
- SNR range =
-10, -8, -6, -4, -2 dB
assumptions (5)
- domain assumption Fault-related periodic impulsive characteristics correspond to identifiable frequency components that can be preserved while noise components are suppressed.
- domain assumption Additive Gaussian white noise is an adequate model for strong industrial noise.
- domain assumption Random train/test splits do not introduce leakage between training and test samples.
- ad hoc to paper TP/(TP+FP) is a valid measure of diagnostic accuracy.
- standard math Standard deep learning primitives (DFT, convolutions, GELU, softmax, batch norm) behave as commonly implemented.
Cite this review
Pith. "Pith review of FE-MCFormer: a novel time-frequency interpretable architecture for machinery fault diagnosis under strong noise environments." pith.science (2026). https://pith.science/paper/QISOHWBR
@misc{pith2026250506285,
author = {Pith},
title = {Pith review of: FE-MCFormer: a novel time-frequency interpretable architecture for machinery fault diagnosis under strong noise environments},
year = {2026},
howpublished = {\url{https://pith.science/paper/QISOHWBR}},
note = {Machine review of arXiv:2505.06285}
}
read the original abstract
Interpretable fault diagnosis (FD) plays a critical role in industrial manufacturing, as it improves human-machine understanding and operational efficiency. However, harsh operating environments often introduce strong background interference or noise, which weakens the discriminative capability and interpretability of existing FD methods. To address this issue, this paper proposes FE-MCFormer, a time-frequency fusion framework for robust and time-frequency interpretable fault diagnosis under strong noise conditions. A frequency adaptive learning layer (FALL) is developed to perform learnable spectral reconstruction, which explicitly suppresses noise-dominated frequency responses while preserving fault-sensitive harmonic structures. Furthermore, a multiscale time-frequency fusion (MSTFF) architecture is designed to jointly capture localized impulsive characteristics and structured global spectral interactions. Extensive experiments on a rolling bearing dataset and a real-world centrifugal compressor dataset demonstrate that the proposed method achieves stable and interpretable diagnostic performance under severe noise environments down to -10 dB SNR. The results indicate that FE-MCFormer provides an effective framework for turbomachinery fault diagnosis in complex noisy environments.
Figures
Figures from the paper (9 more)
Reference graph
Works this paper leans on
-
[1]
Appli- cationsofmachinelearningtomachinefaultdiagnosis:Areviewand roadmap
Lei, Y., Yang, B., Jiang, X., Jia, F., Li, N., Nandi, A.K., 2020. Appli- cationsofmachinelearningtomachinefaultdiagnosis:Areviewand roadmap. Mech. Syst. Signal Process. 138, 106587
work page 2020
-
[2]
Ahmad, H., Cheng, W., Wang, W., Zhang, S., Nie, Z., Liu, H., Chen, X., 2025. Consistency-regularized-label-aware contrastive learning with uncertainty-aware periodic pseudo-labeling for machinery fault diagnosis under limited labeled data. Adv. Eng. Inform. 68, 103656
work page 2025
-
[3]
Zhao, L., Qi, J., Wu, F., Wang, Y., Qin, Y., 2026. Physics modeling-driven interpretable data augmentation method for bear- ing fault diagnosis under imbalanced data. Adv. Eng. Inform. 70, 104189. URL:https://www.sciencedirect.com/science/article/pii/ S1474034625010821, doi:https://doi.org/10.1016/j.aei.2025.104189
-
[4]
Jiang, Z., Zhang, K., Xiang, L., Yu, G., Xu, Y., 2023. A time- frequencyspectralamplitudemodulationmethodanditsapplications in rolling bearing fault diagnosis. Mech. Syst. Signal Process. 185, 109832. doi:10.1016/j.ymssp.2022.109832
-
[5]
Weak fault detection of rolling bearing using a ds-based adaptive spectrum reconstruction method
Xu, Y., Hu, J., 2019. Weak fault detection of rolling bearing using a ds-based adaptive spectrum reconstruction method. J. Instrum. 14, P03022
work page 2019
-
[6]
Chen, Z., Yang, Y., He, C., Liu, Y., Liu, X., Cao, Z., 2023. Feature extractionbasedonhierarchicalimprovedenvelopespectrumentropy for rolling bearing fault diagnosis. IEEE Trans. Instrum. Meas. 72, 1–12. doi:10.1109/TIM.2023.3277938
arXiv 2023
-
[7]
Application of ICEEMDAN energy entropy and AFSA-SVM for fault diagnosis of hoist sheave bearing
Kou, Z., Yang, F., Wu, J., Li, T., 2020. Application of ICEEMDAN energy entropy and AFSA-SVM for fault diagnosis of hoist sheave bearing. Entropy 22, 1347. doi:10.3390/e22121347
-
[8]
Zhou, J., Chen, C., Guo, J., Wang, L., Liu, Z., Feng, C., 2023. A novel rolling bearing fault diagnosis method based on continuous hierarchical fractional range entropy. Measurement 220, 113395. doi:10.1016/j.measurement.2023.113395
arXiv 2023
Show all 37 references
-
[9]
Meta-learning with distributional similarity preference for few-shot fault diagnosis under varying working conditions
Ren, C., Jiang, B., Lu, N., Simani, S., Gao, F., 2024. Meta-learning with distributional similarity preference for few-shot fault diagnosis under varying working conditions. IEEE Trans. Cybern. 54, 2746–
2024
-
[10]
A meta-learning method for electric machine bearing fault diagnosis undervaryingworkingconditionswithlimiteddata
Chen, J., Hu, W., Cao, D., Zhang, Z., Chen, Z., Blaabjerg, F., 2023. A meta-learning method for electric machine bearing fault diagnosis undervaryingworkingconditionswithlimiteddata. IEEETrans.Ind. Inf. 19, 2552–2564. doi:10.1109/TII.2022.3165027
2023
-
[11]
Semi- supervised fault diagnosis of gearbox based on feature pre-extraction mechanismandimprovedgenerativeadversarialnetworksunderlim- ited labeled samples and noise environment
Zhang, L., Wang, B., Liang, P., Yuan, X., Li, N., 2023. Semi- supervised fault diagnosis of gearbox based on feature pre-extraction mechanismandimprovedgenerativeadversarialnetworksunderlim- ited labeled samples and noise environment. Adv. Eng. Inform. 58, 102211. doi:10.1016/...
2023
-
[12]
Ahybridcross-domainfew- shot bearing fault diagnosis method combining multi-scale feature association and physical information
He,C.,Gai,N.,Yan,K.,Shao,H.,2026. Ahybridcross-domainfew- shot bearing fault diagnosis method combining multi-scale feature association and physical information. Adv. Eng. Inform. 69, 104077
2026
-
[13]
Multiscale deep attention q network: A new deep reinforcement learning method for imbalancedfaultdiagnosisingearboxes
Wang, H., Zhou, Z., Zhang, L., Yan, R., 2024. Multiscale deep attention q network: A new deep reinforcement learning method for imbalancedfaultdiagnosisingearboxes. IEEETrans.Instrum.Meas. 73, 1–12. doi:10.1109/TIM.2023.3338664
2024
-
[14]
Xu,Y.,Yan,X.,Feng,K.,Sheng,X.,Sun,B.,Liu,Z.,2022.Attention- basedmultiscaledenoisingresidualconvolutionalneuralnetworksfor fault diagnosis of rotating machinery. Reliab. Eng. Syst. Saf. 226, 108714. doi:10.1016/j.ress.2022.108714
2022
-
[15]
Multiscale residual attention convolutional neural network for bearing fault diagnosis
Jia, L., Chow, T.W.S., Wang, Y., Yuan, Y., 2022. Multiscale residual attention convolutional neural network for bearing fault diagnosis. IEEETrans. Instrum. Meas.71, 1–13. doi:10.1109/TIM.2022.3196742
2022
-
[16]
Remain- ing useful life prediction for the harmonic reducer of industrial robots via in-situ current signal and lightweight multiscale atten- tion deep networks
Yuan, Y., Han, Y., Xiao, K., Xu, Z., Jiang, X., 2025. Remain- ing useful life prediction for the harmonic reducer of industrial robots via in-situ current signal and lightweight multiscale atten- tion deep networks. Journal of Manufacturing Systems 83, 322–
2025
-
[17]
Variational Attention-Based Interpretable Transformer Network for Rotary Ma- chine Fault Diagnosis
Li, Y., Zhou, Z., Sun, C., Chen, X., Yan, R., 2024. Variational Attention-Based Interpretable Transformer Network for Rotary Ma- chine Fault Diagnosis. IEEE Trans. Neural Netw. Learning Syst. 35, 6180–6193
2024
-
[18]
A novel time–frequency Transformer based on self–attention mechanism and its application infaultdiagnosisofrollingbearings
Ding, Y., Jia, M., Miao, Q., Cao, Y., 2022. A novel time–frequency Transformer based on self–attention mechanism and its application infaultdiagnosisofrollingbearings. MechanicalSystemsandSignal Processing 168. Publisher: Elsevier BV
2022
-
[19]
Wd-kantf: An interpretable intelligent fault diagnosis framework for rotating machinery under noise environments and small sample conditions
Zhang, Y., Zhao, X., Peng, Z., Xu, R., Chen, P., 2025. Wd-kantf: An interpretable intelligent fault diagnosis framework for rotating machinery under noise environments and small sample conditions. Adv. Eng. Inform. 66, 103452
2025
-
[20]
Convformer- NSE: A novel end-to-end gearbox fault diagnosis framework under heavy noise using joint global and local information
Han, S., Shao, H., Cheng, J., Yang, X., Cai, B., 2023. Convformer- NSE: A novel end-to-end gearbox fault diagnosis framework under heavy noise using joint global and local information. IEEE/ASME Trans. Mechatron. 28, 340–349. doi:10.1109/TMECH.2022.3199985
2023
-
[21]
YOLOv11: An overview of the key architectural enhancements
Khanam, R., Hussain, M., 2024. YOLOv11: An overview of the key architectural enhancements. URL:http://arxiv.org/abs/2410.17725, arXiv:2410.17725 [cs]
2024 arXiv
-
[22]
Inception-v4, inception-resnet and the impact of residual connections on learning
Szegedy,C.,Ioffe,S.,Vanhoucke,V.,Alemi,A.,2017. Inception-v4, inception-resnet and the impact of residual connections on learning. AAAI 31
2017
-
[23]
DRSwin- ST: An intelligent fault diagnosis framework based on dynamic threshold noise reduction and sparse transformer with shifted win- dows 250, 110327
Zhou, T., Yao, D., Yang, J., Meng, C., Li, A., Li, X., 2024. DRSwin- ST: An intelligent fault diagnosis framework based on dynamic threshold noise reduction and sparse transformer with shifted win- dows 250, 110327
2024
-
[24]
Longformer: The long- document transformer
Beltagy, I., Peters, M.E., Cohan, A., 2020. Longformer: The long- document transformer
2020
-
[25]
Attention is not all you need: Pure attention loses rank doubly exponentially with depth
Dong, Y., Cordonnier, J.B., Loukas, A., 2023. Attention is not all you need: Pure attention loses rank doubly exponentially with depth. URL:http://arxiv.org/abs/2103.03404, doi:10.48550/arXiv. 2103.03404,arXiv:2103.03404 [cs]
-
[26]
One wide feedforward is all you need, in: Proceedings of the Eighth Conference on Machine Translation, Association for Computational Linguistics
Pires, T., Vilarinho Lopes, A., Assogba, Y., Setiawan, H., 2023. One wide feedforward is all you need, in: Proceedings of the Eighth Conference on Machine Translation, Association for Computational Linguistics. pp. 1031–1044
2023
- [27]
-
[28]
org/abs/2105.14103,doi:10.48550/arXiv.2105.14103,arXiv:2105.14103 [cs]
Zhai, S., Talbott, W., Srivastava, N., Huang, C., Goh, H., Zhang, R., Susskind,J.,2021.Anattentionfreetransformer.URL:http://arxiv. org/abs/2105.14103,doi:10.48550/arXiv.2105.14103,arXiv:2105.14103 [cs]. Yuhan Yuan et al.:Preprint submitted to ElsevierPage 15 of 16 FE-MCFormer...
-
[29]
Lessmeier, C., Kimotho, J.K., Zimmer, D., Sextro, W., 2016. Con- dition monitoring of bearing damage in electromechanical drive sys- tems by using motor current signals of electric motors: A benchmark data set for data-driven classification, in: PHM society European conference
2016
-
[30]
Bearing fault diagnosis base on multi-scale cnn and lstm model
Chen, X., Zhang, B., Gao, D., 2021. Bearing fault diagnosis base on multi-scale cnn and lstm model. J. Intell. Manuf. 32, 971–987
2021
-
[31]
Understanding and learning discriminant features based on multiattention 1dcnn for wheelset bearing fault diagnosis
Wang, H., Liu, Z., Peng, D., Qin, Y., 2020. Understanding and learning discriminant features based on multiattention 1dcnn for wheelset bearing fault diagnosis. IEEE Trans. Ind. Inf. 16, 5735–
2020
-
[32]
Deeplearningalgorithmsforrotatingmachineryintelligentdiagnosis: An open source benchmark study
Zhao, Z., Li, T., Wu, J., Sun, C., Wang, S., Yan, R., Chen, X., 2020. Deeplearningalgorithmsforrotatingmachineryintelligentdiagnosis: An open source benchmark study. ISA Trans
2020
-
[33]
LiConvFormer: A lightweight fault diagnosis framework using separable multiscale convolutionandbroadcastself-attention
Yan,S.,Shao,H.,Wang,J.,Zheng,X.,Liu,B.,2024. LiConvFormer: A lightweight fault diagnosis framework using separable multiscale convolutionandbroadcastself-attention. ExpertSystemswithAppli- cations 237, 121338. doi:10.1016/j.eswa.2023.121338
2024
-
[34]
Highly accurate machine fault diagnosis using deep transfer learning
Shao, S., McAleer, S., Yan, R., Baldi, P., 2018. Highly accurate machine fault diagnosis using deep transfer learning. IEEE Trans. Ind. Inf. 15, 2446–2455. Yuhan Yuan et al.:Preprint submitted to ElsevierPage 16 of 16
2018
-
[336]
URL:https://www.sciencedirect.com/science/article/pii/ S0278612525002353, doi:https://doi.org/10.1016/j.jmsy.2025.09.008
2025 doi
-
[2756]
doi:10.1109/TCYB.2023.3338768
2023
-
[5745]
doi:10.1109/TII.2019.2955540
2019
Reviewed August 15, 2026 · model on record in the stance chip above.
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