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Journal of ZheJiang University (Engineering Science)  2026, Vol. 60 Issue (8): 1770-1781    DOI: 10.3785/j.issn.1008-973X.2026.08.016
    
Multi-scale dual-stream architecture for long-term time series forecasting
Meijia WANG1(),Fan ZHANG1,2,*(),Hua WANG3,Mingli ZHANG4,Caiming ZHANG5
1. School of Computer Science and Technology, Shandong Technology and Business University, Yantai 264005, China
2. Shandong Provincial Higher Education Institutions Future Health Intelligent Medical Industry Engineering Research Center, Yantai 264005, China
3. School of Computer and Artificial Intelligence, Ludong University, Yantai 264025, China
4. McGill Centre for Integrative Neuroscience, Montreal Neurological Institute, McGill University, Montreal, H3A 2B4, Canada
5. School of Software, Shandong University, Jinan 250100, China
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Abstract  

A dual-stream framework named Patchflow was proposed to address the limited ability to capture multi-scale dynamic and insufficient nonlinear modeling capability in long-term time series forecasting. A multi-scale segmentation strategy was employed to partition long-term time series into local segments of different granularities, enabling accurate simultaneous modeling of local and global temporal dynamics while enhancing adaptability to multi-frequency patterns. A Chebyshev polynomial-based approximate convolution operator was further introduced to capture inter-segment correlations from a geometric perspective, improving the modeling accuracy of non-stationary sequences. Based on the trend modeling branch, a structured prior was introduced to extract complex temporal dependencies. Experiments on multiple public datasets showed that Patchflow consistently outperformed state-of-the-art methods, with particularly notable improvements on sequences with strong seasonality and long-term trends.



Key wordstime series forecasting      dual-stream architecture      multi-scale segmentation      non-stationary sequences      Chebyshev polynomials     
Received: 24 June 2025      Published: 16 July 2026
CLC:  TP 393  
Fund:  国家自然科学基金联合基金资助项目(U24A20219);国家自然科学基金资助项目(62272281);泰山学者专项基金资助项目(tsqn202306274);山东省高等学校青创科技支持计划(2023KJ212).
Corresponding Authors: Fan ZHANG     E-mail: 2024410048@sdtbu.edu.cn;zhangfan@sdtbu.edu.cn
Cite this article:

Meijia WANG,Fan ZHANG,Hua WANG,Mingli ZHANG,Caiming ZHANG. Multi-scale dual-stream architecture for long-term time series forecasting. Journal of ZheJiang University (Engineering Science), 2026, 60(8): 1770-1781.

URL:

https://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2026.08.016     OR     https://www.zjujournals.com/eng/Y2026/V60/I8/1770


面向长期时间序列预测的多尺度双流架构

针对长期时间序列预测中多尺度动态捕捉不足与非线性建模能力有限的问题,提出名为Patchflow的双流架构. 设计多尺度分割策略,将长期时间序列划分为不同粒度的局部片段,精准同步建模局部与全局时序动态,提升对多频率特征的自适应能力. 引入切比雪夫多项式构建的近似卷积算子,从几何视角刻画片段间相关性,有效增强非平稳序列的建模精度. 在趋势建模的基础上,引入结构化先验以提取复杂时序依赖. 实验结果表明,相较同类方法,Patchflow在多个公开数据集上的预测精度均显著提升,在强季节性与长期趋势性序列上的表现尤为突出.


关键词: 时间序列预测,  双流结构,  多尺度分割,  非平稳序列,  切比雪夫多项式 
Fig.1 Proposed multi-scale dual-stream architecture
Fig.2 Chebyshev polynomial layer
Fig.3 Local-global convolution module
数据集种类Cf
ETTh1,ETTh2变压器温度71 h
ETTm1,ETTm2变压器温度715 min
Weather气象观测2110 min
Traffic道路占用率8621 h
Electricity用电负荷3211 d
Exchange全球8国汇率波动81 d
ILI流感样病例就诊比例77 d
Tab.1 Statistical data of public datasets for benchmarking
数据集MSE
PatchflowxPatchSimpleTMFilterTSPathformerTimeMixerPatchTSTTimesNetMICNDLinear
ETTh10.4200.4280.4230.4340.4390.4470.4460.4580.4400.456
ETTh20.3110.3190.3540.3760.3440.3650.3760.4140.4080.559
ETTm10.3690.3770.3810.3850.3820.3810.3910.4000.4060.403
ETTm20.2610.2670.2750.2770.2730.2750.2820.2910.2900.350
Weather0.2360.2320.2430.2450.2390.2400.2560.2590.2740.265
Traffic0.5000.5000.4440.4700.5010.4850.5150.6200.5850.625
Electricity0.1830.1790.1860.1810.1820.1820.2030.1930.2090.212
Exchange0.3440.3750.4240.3500.4010.4080.3690.4160.5890.354
ILI1.4321.4424.9152.4251.5631.7082.1102.1842.6532.616
Tab.2 Long-term forecasting results of different models on multiple standard multivariate time series datasets (MSE)
数据集MAE
PatchflowxPatchSimpleTMFilterTSPathformerTimeMixerPatchTSTTimesNetMICNDLinear
ETTh10.4130.4190.4280.4300.4300.4400.4410.4500.4620.452
ETTh20.3590.3610.3910.3980.3790.3950.4010.4270.4400.515
ETTm10.3790.3840.3960.3960.3860.3960.4030.4060.4320.407
ETTm20.3100.3130.3220.3220.3160.3230.3250.3330.3430.401
Weather0.2600.2610.2720.2740.2630.2970.2800.2870.3250.317
Traffic0.3100.2790.2880.3150.2990.2980.3320.3360.3500.383
Electricity0.2740.2640.2870.2720.2690.2730.2900.2950.3190.300
Exchange0.3970.4090.4340.3970.4190.4220.4060.4430.5410.414
ILI0.7300.7251.5401.0200.7530.8200.9170.9311.0731.090
Tab.3 Long-term forecasting results of different models on multiple standard multivariate time series datasets (MAE)
数据集TPatchflow去除多尺度聚合去除切比雪夫层
MSEMAEMSEMAEMSEMAE
ETTh1960.3700.3870.3730.3890.3710.388
1920.4170.4010.4330.4130.4170.405
3360.4380.4170.4530.4290.4670.435
7200.4540.4460.4950.4730.4860.462
ETTm1960.2990.3390.3110.3510.3090.342
1920.3410.3630.3540.3690.3550.369
3360.3810.3890.3920.3910.3900.393
7200.4540.4240.4640.4280.4570.429
ETTm2960.1620.2450.1660.2510.1640.248
1920.2270.2870.2310.2910.2300.290
3360.2830.3250.2910.3300.2920.331
7200.3710.3810.3800.3840.3810.383
Weather960.1520.1910.1570.1990.1680.203
1920.2010.2370.2060.2410.2130.245
3360.2560.2800.2640.2850.2670.286
7200.3380.3330.3450.3400.3440.339
Tab.4 Module ablation results of proposed multi-scale dual-stream architecture
数据集TxPatchxPatch*
MSEMAEMSEMAE
ETTh2960.2330.3000.2270.298
1920.2910.3380.2850.335
3360.3440.3770.3430.376
7200.4070.4270.4180.436
ETTm2960.1660.2480.1650.247
1920.2300.2910.2280.290
3360.2920.3310.2900.330
7200.3810.3830.3780.382
Weather960.1680.2030.1580.197
1920.2140.2450.2050.240
3360.2360.2730.2330.272
7200.3090.3210.3060.321
Tab.5 Experimental results of introducing Chebyshev polynomial layer into strong baseline
Fig.4 Comparison of fitting effects for multi-layer perceptrons and Chebyshev polynomial layers
Fig.5 Comparison of input and output features for Chebyshev polynomial layer
Fig.6 Parameter sensitivity analysis of convolutional kernels on ETT dataset
Fig.7 Parameter sensitivity analysis of embedded dimensions on Weather dataset
数据集模型FLOPs/106Par/106I/ms
ETTh1Patchflow123.4718.458.28
xPatch10.421.374.66
SimpleTM0.750.055.61
iTransformer23.802.172.54
Pathformer12.060.54205.41
TimeMixer16.540.129.20
PatchTST1934.6413.5667.24
ETTm1Patchflow123.4218.448.67
xPatch10.421.375.88
SimpleTM0.220.023.87
iTransformer2.800.262.44
Pathformer30.090.87247.52
TimeMixer16.540.128.72
PatchTST140.662.2118.29
ElectricityPatchflow4438.4015.69320.21
xPatch477.921.37221.20
SimpleTM542.810.9060.52
iTransformer1609.864.9693.01
Pathformer3792.404.319893.60
TimeMixer971.680.151410.86
PatchTST5939.852.21615.75
Tab.6 Model complexity analysis
数据集模型FLOPs/106I/msMSEMAE
ETTh1Patchflow113.289.160.4380.417
Patchflow_Lite46.636.480.4390.421
ETTm1Patchflow113.289.580.3810.389
Patchflow_Lite46.636.570.3870.389
ElectricityPatchflow5194.54819.100.1820.275
Patchflow_Lite2138.46140.550.1870.281
Tab.7 Performance evaluation of lightweight models
数据集剪枝类型FLOPs/106I/msMSEMAE
ETTh1无剪枝315.240.3720.388
结构化剪枝316.970.4990.468
非结构化剪枝316.700.3720.388
Electricity无剪枝774.615.660.1540.249
结构化剪枝774.617.030.3410.433
非结构化剪枝774.617.140.1550.250
Tab.8 Model pruning experiment results
模型ETTh1ETTm1Weather
MSEMAEMSEMAEMSEMAE
Patchflow0.1060.2280.0540.1610.0380.089
xPatch0.1630.2830.0710.1850.0500.115
SimpleTM0.2150.3530.1110.2300.0620.128
Tab.9 Comparison of time series interpolation performance across different models
Fig.8 Robustness test results of model under anomalous perturbation
Fig.9 Global scaling factor visualization
Fig.10 Comparison of prediction performance between patch-scale and multi-scale fusion schemes across different datasets
Fig.11 Comparison of predictions and ground truth for two models on Electricity and Weather datasets
Fig.12 Comparison of predictions and ground truth for two models on ETTh1 and ETTm1 datasets
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