# Research on Agricultural Product Price Prediction Based on Improved PSO-GA
## 5 Conclusions  
In this study, an improved PSO-GA weight allocation method is innovatively proposed to determine the optimal weights for the combination models, and a novel forecasting combination framework based on weight optimization is used to analyze the characteristics of scallion price changes in Shandong Province, as well as the robustness, forecasting accuracy, and accuracy of directional changes using various combination models. The conclusions of this study are as follows:  
1. The noise components in the scallion price sequence are removed by SSA, EMD, and VMD decomposition and denoising methods, which makes the sequence smoother and improves the reliability and accuracy of prediction, while reducing the complexity of prediction. This provides a theoretical basis for predicting prices for more minor agricultural products in the future. Meanwhile, after further analyzing the reconstructed series after decomposition and denoising, it is found that the scallion price in Shandong Province from 2014 to 2023 has obvious cyclical and seasonal characteristics, showing the law of \"high in winter and low in summer\". 2. The experimental results show that combining the classical time series forecasting model (ARIMA) and intelligent models (LSTM and GRUs) with different decomposition techniques to construct diversified combination models can harness the advantages of each base model and effectively enhance the comprehensiveness and accuracy of the combination models in capturing sequence information. Compared with a single model, these combined models can significantly reduce the prediction error, and, at the same time, enhance the robustness and adaptability of the model with better generalization ability. This will provide a reference for future researchers in how to choose a base model for a combined model. 3. In the homogeneous, heterogeneous, and semi-heterogeneous combinatorial models, by comparing the three weight assignment methods, namely, the average method, the median method, and the improved PSO-GA, it is found that the semi-heterogeneous-PSO-GA combination model has the lowest error, the highest accuracy, and the best performance. Its MAPE value in predicting large scallions is 1.9209%, which is 8.96% lower than the best single model, SSA-ARIMA. These experimental results indicate that the weights of combinatorial models determined by the PSO-GA method innovated in this study can allow the combinatorial models to have higher horizontal and directional accuracies and can effectively solve the common problems encountered when determining the weights of combinatorial models, such as slow convergence speed, ease of falling into local optimal solutions, poor adaptability, and so on. In terms of social impact, the accurate prediction of scallion prices through this research method can not only optimize supply chain management and help related practitioners and consumers make more reasonable purchasing decisions, but also guide farmers' planting choices and improve market efficiency, which is of great theoretical and practical significance to promote the sustainable development of the scallion industry. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Target Model:** \\ **Full-Based** \\ \end{tabular} } & \multicolumn{3}{c}{**Benchmark Model**} & \multirow{2}{*}{\begin{tabular}{c} **PSO-GA-** \\ **ARIMA** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **PSO-GA-** \\ **LSTM** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **PSO-GA-** \\ **VMD** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **PSO-GA-** \\ **EMD** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **PSO-GA-** \\ **Model** \\ \end{tabular} } \\ \hline DMstat & \(-2.3575\) & \(-3.3081\) & \(-2.3502\) & \(-2.3500\) & \(-2.3628\) & \(-2.3478\) & \(-2.3941\) \\ \hline \(p\)-value & 0.0204 & 0.0013 & 0.0207 & 0.0208 & 0.0201 & 0.0209 & 0.0185 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: DM test results of PSO-GA under different sub-strategies for scallion price.