Real-time information dissemination is essential for the success of key applications such as transportation management and battlefield monitoring. In these applications, relevant information should be disseminated to interested users in a timely fashion. However, it is challenging to support timely information dissemination due to the limited and even time-varying network bandwidth. Thus, a naive approach disseminating every data with no consideration of the context that describes where and when the data is acquired and how it can satisfy users may only provide poor performance and user perceived quality of service (QoS). To address the problem, we design a novel context-aware protocol to disseminate real-time data in a cost-effective manner by considering the spatio-temporal semantics associated with information. More specifically, we define (1) context attributes, (2) develop how to analyze the utility of a specific data item based on the attributes, (3) and adjust the utility based...