Triggers and Queries in Distributed Software Systems for Moving Objects

该项目建议研究分布式系统，该系统可以监控各种移动物体的位置，并根据其位置处理查询和触发器。这种系统的应用，称为移动目标信息（MOI）应用，通常发生在民用部门的运输系统和军事的数字战场管理中。该建议考虑了MOI系统的两种不同的体系结构模型；在第一个系统中，一个单一的中央服务器（CS）监视对象的位置并回答查询；第二个体系结构是完全分布式的，其中移动对象相互通信以回答查询并监视触发条件。该项目提出了各种位置更新策略，用于维护CS模型中对象的位置信息。所有这些策略都将对象的位置维护为随时间变化的动态属性。该项目计划通过分析和实验研究来调查这些政策的成本效益。提出了一种基于未来时态逻辑（FTL）的查询语言，用于指定运动对象的时空查询和触发条件。该语言允许在答案中指定所需的不确定程度。提出了在这两种体系结构中开发高效查询/触发处理机制的研究方向。提出的机制将在实验测试台上进行评估。

The project proposes research on distributed systems that monitor the positions of various moving objects and process queries and triggers referring to their positions. Applications of such systems, called Moving Object Information (MOI) applications, typically occur in transportation systems in the civilian sector and in the digital battlefield management in the military. This proposal considers two different architecture models for the MOI systems; in the first one a single central server (CS) monitors the position of the objects and answers queries; the second architecture is fully distributed in which the moving objects communicate with each other to answer the queries and to monitor trigger conditions. The project proposes various location update policies for maintenance of the position information of the objects in the CS model. All these policies maintain the position of an object as a dynamic attribute that changes with time. The project plans to investigate the cost effectiveness of these policies through analytical and experimental studies. A query language based on Future Temporal Logic (FTL) is proposed for specifying spatial and temporal queries and trigger conditions on the moving objects. The language permits specification of the desired levels of uncertainties in the answer. Research towards the development of efficient query/trigger processing mechanisms in the two architectures are proposed. The proposed mechanisms will be evaluated in an experimental testbed.