Metaverse has recently attracted much attention from both academia and
industry. Virtual services, ranging from virtual driver training to online
route optimization for smart goods delivery, are emerging in the Metaverse. To
make the human experience of virtual life more real, digital twins (DTs),
namely digital replicas of physical objects, are key enablers. However, DT
status may not always accurately reflect that of its real-world twin because
the latter may be subject to changes with time. As such, it is necessary to
synchronize a DT with its physical counterpart to ensure that its status is
accurate for virtual businesses in the Metaverse. In this paper, we propose a
dynamic hierarchical framework in which a group of IoT devices is incentivized
to sense and collect physical objects' status information collectively so as to
assists virtual service providers (VSPs) in synchronizing DTs. Based on the
collected sensing data and the value decay rate of the DTs, the VSPs can
determine synchronization intensities to maximize their payoffs. In our
proposed dynamic hierarchical framework, the lower-level evolutionary game
captures the VSPs selection by the IoT device population, and the upper-level
differential game captures the VSPs payoffs, which are affected by the
synchronization strategy, IoT devices selections, and the DTs value status,
given VSPs are simultaneous decision makers. We further consider the case in
which some VSPs are first movers and extend it as a Stackelberg differential
game. We theoretically and experimentally show that the equilibrium to the
lower-level game exists and is evolutionarily robust, and provide a sensitivity
analysis with respect to various system parameters. Experiments show that the
proposed dynamic hierarchical game outperform the baseline.

本文提出了一种动态层次结构框架，其中一组物联网设备被激励相互感应和收集物理对象的状态信息，并协助虚拟服务提供商同步数字孪生，以最大化其利润。通过理论和实验分析，证明了该框架的有效性及其优于基准线的性能。

物联网辅助元宇宙同步的动态分层框架

A Dynamic Hierarchical Framework for IoT-assisted Metaverse  Synchronization

Spurred by the severe restrictions on mobility due to the COVID-19 pandemic,
there is currently intense interest in developing the Metaverse, to offer
virtual services/business online. A key enabler of such virtual service is the
digital twin, i.e., a digital replication of real-world entities in the
Metaverse, e.g., city twin, avatars, etc. The real-world data collected by IoT
devices and sensors are key for synchronizing the two worlds. In this paper, we
consider the scenario in which a group of IoT devices are employed by the
Metaverse platform to collect such data on behalf of virtual service providers
(VSPs). Device owners, who are self-interested, dynamically select a VSP to
maximize rewards. We adopt hybrid evolutionary dynamics, in which heterogeneous
device owner populations can employ different revision protocols to update
their strategies. Extensive simulations demonstrate that a hybrid protocol can
lead to evolutionary stable states.

本研究旨在探讨在 Metaverse 中，利用 IoT 设备进行数字孪生同步，实现虚拟服务提供商与真实世界实体的连接；并采用混合进化动力学算法，以实现设备选择虚拟服务提供商的动态优化，最终得到一种进化稳定状态。