融合IDA-GRU和IIDW的水产养殖溶解氧时空预测模型

    Spatiotemporal prediction model of dissolved oxygen in aquaculture intergrating IDA-GRU and IIDW

    • 摘要: 为了提高大面积水产养殖中养殖效率、降低养殖风险、提高溶解氧(dissolved oxygen,DO)时空预测精度,该研究基于双重注意力机制改进的门控循环单元(improved gated recurrent unit based on dual attention mechanism,IDA-GRU)和改进逆距离加权插值算法(improved inverse distance weighting interpolation algorithm,IIDW),提出了一种改进的水产养殖溶解氧时空预测模型。首先在门控循环单元(gated recurrent unit,GRU)的基础上,引入特征和时间双重注意力机制(dual attention,DA),实现溶解氧时间序列预测,其中特征注意力机制实时计算各环境特征的贡献率,不断修正各环境特征的权重,时间特征注意力机制自主地提取关键历史时刻信息;然后在溶解氧时间序列的基础上,利用IIDW算法实现溶解氧空间预测,该算法中提出的距离权重校正系数,能够实时调整插值权重。最后,在上海城市电力公司数字化生态养殖基地对该模型进行了试验验证。试验结果表明,对于溶解氧时间序列预测,该研究提出的IDA-GRU模型评价指标均方误差、均方根误差、平均绝对误差分别为0.0687 mg2/L2、0.2621 mg/L 和0.2051 mg/L,优于对比模型;对于溶解氧空间预测,该研究提出的IIDW算法,其均方误差、均方根误差、平均绝对误差分别为 0.2088 mg2/L2、 0.4570 mg/L和 0.3835 mg/L,均优于对比算法。该研究提出的模型提高了溶解氧时空预测精度,对提升大面积水产养殖防灾能力,实现水质智能化调控具有重要的推动作用。

       

      Abstract: Dissolved oxygen (DO) in water is one of the most important ecological factors for the healthy growth of aquaculture organisms. The too high concentration can easily cause the fish bubble disease. The low concentration can slow down the growth of fish, where the prolonged floating head can cause the fish to float. There are temporal and spatial variations in the DO of aquaculture water under various environmental factors in large-scale aquaculture. The existing predictions cannot accurately describe the spatial distribution of DO, due to the time series. In this study, an improved prediction model of spatiotemporal DO was presented for the intelligent control of water quality in ponds. The high aquaculture efficiency with fewer risks was then realized using an improved gated recursive unit using a dual attention mechanism (IDA-GRU) and an improved inverse distance weighted interpolation algorithm (IIDW). Firstly, the feature and temporal attention mechanism were introduced to improve the prediction accuracy of DO using the gated recurrent unit (GRU), according to the correlation between parameters and the dependence relationship of temporal information. The key environmental features were also strengthened using the feature attention mechanism. The contribution rate of each environmental feature was then calculated to continuously modify the weight of each environmental feature in real time. The time attention mechanism autonomously extracted the key historical moments, and then enhanced the expression of the key moment, thus improving the stability of DO time prediction. Secondly, an improved inverse distance-weighted interpolation (IDW) was applied to achieve spatial prediction using the prediction of DO time series. The distance weight correction coefficient was also introduced using the traditional inverse distance-weighted interpolation. The interpolation weights were adjusted in real time, according to the DO content at each monitoring point. An improved accuracy was achieved in the three-dimensional spatial interpolation of DO. The local environment was considered around the monitoring points. As such, the interpolation weights were changed concurrently rather than that in the traditional algorithm, once the interpolation distance was determined. Finally, the improved model was validated at the digital eco-farming site of Shanghai City electric development Co. The experimental results showed that the mean square error (MSE), root mean square error (RMSE), and mean absolute error (MAE) of the evaluation indexes were 0.0687 mg2/L2, 0.2621 mg/L, and 0.2051 mg/L, respectively, in the IDA-GRU model for the DO time series prediction. Additionally, the MSE, RMSE, and MAE of the IIDW were 0.2088 mg2/L2, 0.4570 mg/L, and 0.3835 mg/L, respectively, for the spatial prediction of DO. A better performance was achieved, compared with the previous models. The present model had improved the accuracy of spatiotemporal DO prediction. The finding can also provide a strong reference for disaster prevention and intelligent regulation of water quality in large-scale aquaculture.

       

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