I. Introduction
Under the background of carbon peaking and carbon neutrality, industrial processes urgently seek intellectual transformation and upgrading, with real-time monitoring, control, and optimization of processes being among the most important tasks [1], [2]. Usually, real-time measurement of key quality variables is the most effective reflection of the industrial manufacturing state. Unfortunately, due to the limitations of measurement techniques and the industrial environment, most of these quality variables cannot be measured in time [3]. This leads to large time delays in industrial process control and optimization [4]. In this context, the soft sensor techniques for predicting difficult-to-measure quality variables using easy-to-measure process variables emerge as time requires [5], [6].