Improving Air Quality Prediction with a Hybrid Bi-LSTM and GAN Model

Abstract

Air quality is a topic that has been of utmost concern across the globe for the past few decades. Various intelligent monitoring systems are used in diverse scenarios, collecting air quality data that contains missing values. Such missing values in data cause hindrances in forecasting. This time series prediction or forecasting process extracts the necessary information from historical records and predicts future values. To solve the missing values issue in data, Generative Adversarial Networks (GAN) are used to impute the missed data. While the learning of long-term dependencies embedded in the time series poses another threat to the models in the time prediction. To overcome this, Long Short-Term Memory (LSTM) models are used. Yet, most of the neural network-based methods failed to consider the patterns of time series data that varied for each period, and the encoder-decoder performance deteriorated for longer sequences. To combat this, the present study proposes a hybrid probabilistic model to generate parameters for predictive distribution at every step. Hence, an implementation of hierarchical-attention-based BiLSTM with GAN is proposed in the study for effective prediction and minimal error. The proposed model is assessed with the evaluation metrics such as Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE), Root Mean Square Error (RMSE), and Mean Square Error (MSE). The evaluation metric confirmed the higher accuracy of the proposed model than the existing models in time series prediction.