Stochastic Variational Bayesian Learning of Wiener Model in the Presence of Uncertainty
-
摘要: 多重不確定性環境下的非線性系統辨識是一個開放問題. 貝葉斯學習在描述、處理不確定性方面具有顯著優勢, 已在線性系統辨識方面得到廣泛應用, 但在非線性系統辨識的應用較少, 面臨概率估計復雜、計算量大等困難. 針對上述問題, 以典型維納(Wiener)非線性過程為對象, 提出基于隨機變分貝葉斯的非線性系統辨識方法. 首先對過程噪聲、測量噪聲以及參數不確定性進行概率描述; 然后利用隨機變分貝葉斯方法對模型參數進行后驗估計. 在估計過程中, 利用隨機優化思想, 僅利用部分中間變量概率信息估計模型參數分布的自然梯度期望, 與利用所有中間變量概率信息估計模型參數比較, 顯著降低了計算復雜性. 該方法是首次在系統辨識領域中的應用. 本文利用一個仿真實例和一個維納模型的Benchmark問題, 證明了該方法在對大規模數據系統辨識時的有效性.Abstract: Nonlinear system identification in uncertain environment is an open problem. Bayesian learning has significant advantages in describing and dealing with uncertainties and has been widely used in linear system identification. However, the use of Bayesian learning for nonlinear system identification has not been well studied due to the complexity of the estimation of the probability, especially in the presence of large-scale data. Motivated by these problems, this paper proposes a nonlinear system identification method based on stochastic variational Bayesian for Wiener model, a typical nonlinear model. First, the process noise, measurement noise and parameter uncertainty are described in terms of probability distribution. Then, the posterior estimation of model parameters is carried out by using the stochastic variational Bayesian approach. In this framework, only a few intermediate variables are used to estimate the natural gradient of the lower bound function of the likelihood function. Compared with classical variational Bayesian approach, where the estimation of model parameters depends on the information of all the intermediate variables, the computational complexity is significantly reduced for the proposed method since it only depends on the information of a few intermediate variables. To the best of our knowledge, it is the first time to use the stochastic variational Bayesian to system identification. A numerical example and a Benchmark problem of Wiener model are used to show the effectiveness of this method in the nonlinear system identification in the presence of large-scale data.
-
表 1 不同子采樣數據點對應的參數辨識情況
Table 1 Identification of parameters corresponding to different sub-sampling data points
$ \langle \theta _0 \rangle $ $ \langle \theta _1 \rangle $ $ \langle \theta _2 \rangle $ $ \langle \theta _3 \rangle $ $ \langle \theta _4 \rangle $ $ \langle \lambda _0 \rangle $ $ \langle \lambda _1 \rangle $ $ \langle \lambda _2 \rangle $ 時間(s) 真實值 1 ?0.5000 0.2500 ?0.1250 0.0625 0 1 1 — 采樣1個點 1±0 ?0.5463±0.3604 0.2507±0.2471 ?0.2446±0.2655 0.0358±0.2882 0.5434±0.4180 0.6625±0.2907 0.3803±0.2185 0.6005 采樣5% 1±0 ?0.5060±0.0330 0.2693±0.0497 ?0.1252±0.0323 0.0633±0.0323 0.0908±0.2707 0.9871±0.1480 0.9103±0.1246 3.1829 采樣10% 1±0 ?0.5055±0.0248 0.2571±0.02567 ?0.1341±0.0255 0.0594±0.0256 0.0631±0.0504 0.9684±0.0498 0.9499±0.0459 7.7402 采樣20% 1±0 ?0.5077±0.0204 0.2544±0.0202 ?0.1287±0.0289 0.0659±0.0291 0.0575±0.0540 0.9813±0.0518 0.9574±0.0451 11.4620 采樣全部 1±0 ?0.5078±0.0278 0.2541±0.0283 ?0.1299±0.0271 0.0685±0.0246 0.0777±0.0726 0.9439±0.1183 0.9252±0.1326 9.0772 表 2 不同異常值存在時的參數辨識情況
Table 2 Parameter identification when different outliers exist
$ \langle \theta _0 \rangle $ $ \langle \theta _1 \rangle $ $ \langle \theta _2 \rangle $ $ \langle \theta _3 \rangle $ $ \langle \theta _4 \rangle $ $ \langle \theta _5 \rangle $ 時間 (s) 真實值 1 ?0.5000 0.2500 ?0.1250 0.0625 ?0.03125 — 無異常值 1±0 ?0.4989±0.0292 0.2495±0.0293 ?0.1254±0.0223 0.0611±0.0257 ?0.0338±0.0262 2.9369 2% 異常值 1±0 ?0.5097±0.0389 0.2672±0.0497 ?0.1305±0.0426 0.0652±0.0452 ?0.0291±0.0494 2.9480 5% 異常值 1±0 ?0.5060±0.0330 0.2693±0.0497 ?0.1252±0.0323 0.0633±0.0323 ?0.0314±0.0523 3.1829 10% 異常值 1±0 ?0.5349±0.0325 0.2627±0.0323 ?0.1314±0.0330 0.0685±0.0389 ?0.0377±0.0355 2.9057 表 3 不同辨識方法的性能比較
Table 3 Performance comparison of different recognition methods
$ b_0 $ $ a_1 $ $ \langle \lambda _0 \rangle(\lambda_0) $ $ \langle \lambda _1 \rangle(\lambda_1) $ $ \langle \lambda _2 \rangle(\lambda_2) $ 均方誤差 時間(s) 真實值 1 0.5 0 1 1 — — 無異常值 SVBI — — 0.0648±0.0620 0.9633±0.0509 0.9766±0.0626 0.9136 2.936 9 VBEM — — 0.0503±0.0346 0.9411±0.0393 0.9655±0.0459 0.8978 9.7046 MLE 1±0 0.5102±0.0136 0.1054±0.0405 1.0154±0.0464 0.9490±0.0411 0.9130 9.0350 PEM 1±0 0.4948±0.0172 0.0828±0.0524 0.9905±0.0373 1.0072±0.0449 0.9132 0.6474 5% 異常值 SVBI — — 0.0575±0.0540 0.9813±0.0520 0.9573±0.0450 5.4540 2.9352 VBEM — — 0.0503±0.0411 0.9770±0.0532 0.9748±0.0518 3.8695 9.7709 MLE 1±0 0.4150±0.0711 ?0.9407±0.1253 1.0019±0.1839 1.3715±0.1895 3.9574 9.6693 PEM 1±0 0.4999±0.0549 0.1072±0.1871 0.9646±0.1926 0.9878±0.1558 3.8374 0.6580 10% 異常值 SVBI — — 0.1439±0.1065 0.9163±0.0924 0.8416±0.0924 7.5364 2.9057 VBEM — — 0.0556±0.0468 0.9711±0.0538 0.9568±0.0553 5.5110 9.9245 MLE — — — — — — — PEM 1±0 0.4723±0.2004 0.1458±0.5211 0.9746±0.3091 1.0030±0.3253 5.4992 0.6620 表 4 過程(52)部分參數辨識結果
Table 4 The identification result of the part of the process (52)
參數 $\theta_0$ $\theta_1$ $\theta_2$ $\theta_3$ $\theta_4$ $\theta_5$ $\theta_6$ $\theta_7$ $\theta_8$ $\theta_9$ $c_0$ $c_1$ $c_2$ $Q$ $R$ 結果值 ?0.0390 0.0648 ?0.0547 0.0856 ?0.0462 0.2613 0.0501 0.2041 0.3396 0.4154 ?0.0188 0.1035 ?0.003 0.0034 0.0014 表 5 不同方法的性能比較
Table 5 Performance comparison of different methods
采樣點數 方法 均方誤差(V) 參數個數 時間(s) 2 000 SVBI 0.056 95 25 256.12 VBEM 0.062 83 25 1 211.27 SVBI 0.034 07 40 264.273 VBEM 0.034 25 40 1 214.55 10 000 SVBI 0.061 79 25 1 299.99 VBEM 0.093 34 25 6 347.28 SVBI 0.033 85 40 1 332.31 VBEM 0.034 04 40 6 442.98 亚洲第一网址_国产国产人精品视频69_久久久久精品视频_国产精品第九页 -
[1] 王樂一, 趙文虓. 系統辨識: 新的模式、挑戰及機遇. 自動化學報, 2013, 39(7): 933?942 doi: 10.1016/S1874-1029(13)60062-2Wang Le-Yi, Zhao Wen-Xiao. System identification: New paradigms, challenges, and opportunities. Acta Automatica Sinica, 2013, 39(7): 933?942 doi: 10.1016/S1874-1029(13)60062-2 [2] 劉鑫. 時滯取值概率未知下的線性時滯系統辨識方法. 自動化學報, 2023, 49(10): 2136?2144Liu Xin. Identification of linear time-delay systems with unknown delay distributions in its value range. Acta Automatica Sinica, 2023, 49(10): 2136?2144 [3] Stoica P. On the convergence of an iterative algorithm used for Hammerstein system identification. IEEE Transactions on Automatic Control, 1981, 26(4): 967?969 doi: 10.1109/TAC.1981.1102761 [4] 張亞軍, 柴天佑, 楊杰. 一類非線性離散時間動態系統的交替辨識算法及應用. 自動化學報, 2017, 43(1): 101?113Zhang Ya-Jun, Chai Tian-You, Yang Jie. Alternating identification algorithm and its application to a class of nonlinear discrete-time dynamical systems. Acta Automatica Sinica, 2017, 43(1): 101?113 [5] 黃玉龍, 張勇剛, 李寧, 趙琳. 一種帶有色量測噪聲的非線性系統辨識方法. 自動化學報, 2015, 41(11): 1877?1892Huang Yu-Long, Zhang Yong-Gang, Li Ning, Zhao Lin. An identification method for nonlinear systems with colored measurement noise. Acta Automatica Sinica, 2015, 41(11): 1877?1892 [6] Ljung L. Perspectives on system identification. Annual Reviews in Control, 2008, 34(1): 1?12 [7] Sch?n T B, Wills A, Ninness B. System identification of nonlinear state-space models. Automatica, 2011, 47(1): 39?49 doi: 10.1016/j.automatica.2010.10.013 [8] Billings S A. Nonlinear System Identification: NARMAX Methods in the Time, Frequency, and Spatio-Temporal Domains. Chichester: John Wiley & Sons, 2013. [9] Carini A, Orcioni S, Terenzi A, Cecchi S. Nonlinear system identification using wiener basis functions and multiple-variance perfect sequences. Signal Processing, 2019, 160: 137?149 doi: 10.1016/j.sigpro.2019.02.017 [10] Schoukens M, Tiels K. Identification of block-oriented nonlinear systems starting from linear approximations: A survey. Automatica, 2017, 85: 272?292 doi: 10.1016/j.automatica.2017.06.044 [11] Bershad N J, Celka P, McLaughlin S. Analysis of stochastic gradient identification of Wiener-Hammerstein systems for nonlinearities with Hermite polynomial expansions. IEEE Transactions on Signal Processing, 2001, 49(5): 1060?1072 doi: 10.1109/78.917809 [12] Valarmathi K, Devaraj D, Radhakrishnan T K. Intelligent techniques for system identification and controller tuning in pH process. Brazilian Journal of Chemical Engineering, 2009, 26(1): 99?111 doi: 10.1590/S0104-66322009000100010 [13] Zhu Y. Distillation column identification for control using wiener model. In: Proceedings of the American Control Conference (Cat. No. 99CH36251). San Diego, USA: IEEE, 1999. 3462-3466 [14] Schoukens J, Suykens J, Ljung L. Wiener-Hammerstein benchmark. In: Proceedings of the 15th IFAC Symposium on System Identification (SYSID 2009). Malo, France, 2009. [15] Hagenblad A, Ljung L, Wills A. Maximum likelihood identification of wiener models. Automatica, 2008, 44(11): 2697?2705 doi: 10.1016/j.automatica.2008.02.016 [16] Xu W Y, Bai E W, Cho M. System identification in the presence of outliers and random noises: A compressed sensing approach. Automatica, 2014, 50(11): 2905?2911 doi: 10.1016/j.automatica.2014.10.017 [17] Bottegal G, Castro-Garcia R, Suykens J A K. A two-experiment approach to wiener system identification. Automatica, 2018, 93: 282?289 doi: 10.1016/j.automatica.2018.03.069 [18] Westwick D T, Schoukens J. Initial estimates of the linear subsystems of Wiener-Hammerstein models. Automatica, 2012, 48(11): 2931?2936 doi: 10.1016/j.automatica.2012.06.091 [19] Giordano G, Gros S, Sj?berg J. An improved method for Wiener-Hammerstein system identification based on the fractional approach. Automatica, 2018, 94: 349?360 doi: 10.1016/j.automatica.2018.04.046 [20] Liu Q, Lin W Y, Jiang S L, Chai Y, Sun L. Robust estimation of wiener models in the presence of outliers using the VB approach. IEEE Transactions on Industrial Electronics, 2021, 68(11): 11390?11399 doi: 10.1109/TIE.2020.3028806 [21] Xie L, Yang H Z, Huang B. FIR model identification of multirate processes with random delays using EM algorithm. AIChE Journal, 2013, 59(11): 4124?4132 doi: 10.1002/aic.14147 [22] Agamennoni G, Nieto J I, Nebot E M. Approximate inference in state-space models with heavy-tailed noise. IEEE Transactions on Signal Processing, 2012, 60(10): 5024?5037 doi: 10.1109/TSP.2012.2208106 [23] Bishop C M. Pattern Recognition and Machine Learning. New York: Springer, 2006. [24] Amari S I. Natural gradient works efficiently in learning. Neural Computation, 1998, 10(2): 251?276 doi: 10.1162/089976698300017746 [25] Amari S I. Differential geometry of curved exponential families-curvatures and information loss. The Annals of Statistics, 1982, 10(2): 357?385 [26] Bottou L. On-line learning and stochastic approximations. On-line Learning in Neural Networks. New York: Cambridge University Press, 1999. [27] Robbins H, Monro S. A stochastic approximation method. The Annals of Mathematical Statistics, 1951, 22(3): 400?407 doi: 10.1214/aoms/1177729586 [28] Hoffman M D, Blei D M, Wang C, Paisley J. Stochastic variational inference. The Journal of Machine Learning Research, 2013, 14(1): 1303?1347
計量
- 文章訪問數: 526
- HTML全文瀏覽量: 172
- 被引次數: 0