水下油气作业的虚拟维修仿真中涉及多种维修案例,而现有的建模技术侧重于仿真实体及场景的几何属性和物理属性等底层模型描述,缺乏从高层应用角度对动态作业流程进行抽象和描述。为此,提出并建立了一种支持水下虚拟维修的高层仿真描述模型HDMUM(A High-level Descriptive Simulation Model for Underwater Virtual Maintenance)。该模型分别对组成水下虚拟维修的三要素:仿真实体,作业场景和维修作业流程从高层应用的角度进行抽象和描述,以动态维修流程为核心建立它们之间的逻辑关系,支持用户在应用层灵活构建不同维修案例,最后通过应用实例验证了模型的合理性和可行性。
Due to its character of topology independency, topology-transparent medium access control (MAC) scheduling algorithm is very suitable for large-scale mobile ad hoc wireless networks. In this paper, we propose a new topologytransparent MAC scheduling algorithm, with parameters of the node number and the maximal nodal degree known, our scheduling algorithm is based on a special balanced incomplete block design whose block size is optimized by maximizing the guaranteed throughput. Its superiority over typical other scheduling algorithms is proven mathematically with respect to the guaranteed throughput, the maximal transmission delay, and also the minimal transmission delay. The effect of inaccuracy in the estimation of the maximal nodal degree on the guaranteed throughput is deduced mathematically, showing that the guaranteed throughput decreases almost linearly as the actual nodal degree increases. Further techniques for improving the feasibility of the algorithm, such as collision avoidance, time synchronization, etc., are also discussed.
