I. Introduction
Industrial Internet of Things (IIoT) and digital twins (DTs) have emerged as two significant driving forces leading the industrial revolution [1], [2]. IIoT enable the intelligent manufacturing, intellectual management, and production optimization in the factory, by connecting sensors, devices, and production lines to the Internet, and thereby facilitating the real-time data collection and exchange [3], [4], [5], [6]. Besides, the DT, as the crucial component of the IIoT, utilizes digital technologies and data models to connect physical entities with their virtual counterparts, promoting the instantaneous monitoring, simulation, and prediction on physical entities. Thus, the production efficiency, cost reduction and product quality are further improved. In particular, DTs have been extensively applied in various fields [7], [8], [9], [10]. In the urban planning, by establishing a digital model of the city, DTs can simulate urban traffic flow, energy consumption and environmental pollution, contributing to the optimization of urban infrastructure layout and resource allocation [11]. Further, in the agriculture, crop growth environments and requirements can be simulated, rendering wiser decisions [12]. Besides, by leveraging DTs in the industrial manufacturing sector, one can promote the monitoring and optimization of production line operations, the prediction of maintenance needs, the improvement of equipment utilization, and the reduction of failure rates [13], [14].