Context-sensitive object request broker for ubiquitous computing environments.

摘要

Object Request Brokers (ORBs), which are building blocks of distributed object computing (DOC) middleware, have shown success in facilitating communications among object-based software in distributed, fixed-network environments. Devices in ubiquitous computing environments form webs of short-range and low-power mobile ad hoc networks to exchange information with each other. Application software systems in ubiquitous computing environments are usually context-sensitive; they take different actions adaptively in different contexts (e.g., location, time). Due to these characteristics, existing ORBs are not suitable for ubiquitous computing environments.; This dissertation presents research results for developing context-sensitive ORBs to provide context-sensitive communications among distributed object-based software in ubiquitous computing environments. Context-sensitive communications enable distributed objects to spontaneously interact with each other based on changes in specific contexts, rather than explicit instructions from the objects themselves.; First, a context-sensitive middleware framework is developed to facilitate context-triggered object activation. Second, an inter-ORB protocol is generated that is capable of dynamically discovering remote objects and providing inter-object communications in mobile ad hoc networks. Third, an energy-efficient inter-ORB protocol is developed for conserving the limited battery power of a device during object discovery. The research results have been applied to develop Reconfigurable Context-Sensitive Middleware Object Request Broker (R-ORB). Experimental results indicate that R-ORB is lightweight, energy-efficient, and has good performance for battery-powered handheld devices.