异步环境中普适上下文的行为一致性约束检测
Checking Behavioral Consistency Constraints for Pervasive Context in Asynchronous Environments
摘要：
上下文一致性检查是上下文感知应用中必不可少的一部分，它是对上下文属性的特定约束的检查。为了描述和适应普适计算环境中的动态变化，上下文感知应用程序通常需要指定和检查上下文上的行为一致性约束。这个问题是具有挑战性的，主要是由于分布式和异步的普适计算环境的性质。具体而言，检查行为约束的关键问题是上下文活动的时间顺序。上下文活动通常涉及多个上下文收集设备，这些设备是完全分散的并且以异步方式交互。然而，现有的上下文一致性检查方案不工作在异步环境中，因为它们隐含地假设一个全局时钟的可用性或中继同步的交互。为此，我们提出了有序的全球活动（OGA）算法，它检测的基础上谓词检测在异步环境中的全球活动的顺序。我们的方法的本质是消息的因果关系和它的动态编码为异步环境中的逻辑向量时钟。我们实现了在异步环境中的谓词检测的中间件基础设施（MIPA），OGA算法的实现和评估。评估结果表明，行为一致性约束检查的影响，这证明了我们的工作的主要动机。实验结果还表明，OGA可以在动态普适计算环境中实现行为一致性约束的精确检测。
英文摘要：
Context consistency checking, the checking of specified constraint on properties of contexts, is essential to context-aware applications. In order to delineate and adapt to dynamic changes in the pervasive computing environment, context-aware applications often need to specify and check behavioral consistency constraints over the contexts. This problem is challenging mainly due to the distributed and asynchronous nature of pervasive computing environments. Specifically, the critical issue in checking behavioral constraints is the temporal ordering of contextual activities. The contextual activities usually involve multiple context collecting devices, which are fully-decentralized and interact in an asynchronous manner. However, existing context consistency checking schemes do not work in asynchronous environments, since they implicitly assume the availability of a global clock or relay on synchronized interactions. To this end, we propose the Ordering Global Activity (OGA) algorithm, which detects the ordering of the global activities based on predicate detection in asynchronous environments. The essence of our approach is the message causality and its on-the-fly coding as logic vector clocks in asynchronous environments. We implement the Middleware Infrastructure for Predicate detection in Asynchronous environments (MIPA), over which the OGA algorithm is implemented and evaluated. The evaluation results show the impact of asynchrony on the checking of behavioral consistency constraints, which justifies the primary motivation of our work. They also show that OGA can achieve accurate checking of behavioral consistency constraints in dynamic pervasive computing environments.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
