Triggers and Queries in Distributed Software Systems for Moving Objects

该项目提出了对分布式系统的研究，该系统监控各种移动对象的位置，并处理涉及其位置的查询和触发器。这种系统的应用，称为移动对象信息(MOI)应用，通常发生在民用部门的交通系统和军事中的数字战场管理中。该方案考虑了MOI系统的两种不同的体系结构模型；在第一种体系结构中，单个中央服务器(CS)监视对象的位置并回答查询；第二种体系结构是完全分布式的，在该体系结构中，移动对象彼此通信以回答查询并监视触发条件。本项目提出了各种位置更新策略来维护CS模型中对象的位置信息。所有这些策略都将对象的位置保持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，用于描述移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的查询/触发器处理机制的研究。所提出的机制将在实验试验台上进行评估。

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.