Usable and efficient abstractions for wireless sensor networks

无线传感器网络由部署在各种环境中的廉价、功率不足且相当不可靠的无线设备/节点组成，以允许远程获取感测数据。传输是昂贵的，因为它们需要节点可用的大量能量。为了解决这个问题，我们在网络中收集和汇总温度、运动、压力等感测数据，以减少最终需要传输的数据总量。希望为无线传感器网络开发应用程序的应用程序编程人员需要能够将应用程序需求转化为每个节点的计算和通信任务。然而，由于这些节点的资源有限，它们没有高端计算设备所提供的奢侈品，这些设备可以运行功能齐全的操作系统。因此，问题就变成了什么应该是允许开发广泛应用程序的最小功能集，并且可以在传感器节点的有限资源中合并。同时，应该能够正确和轻松地推断应用程序逻辑。这就是为什么最低限度的一套能力应该伴随着计算和通信模型。本质上，通信和计算模型充当了应用程序开发的框架。我们的建议正好解决了这个问题，即，开发应用程序的哪些抽象和模型适合无线传感器节点。我们使用我们的经验，从理论结果到实现这样的网络。该提案强调如何利用大量的传感器节点来提供一种“公共”形式的资源，在这种资源上可以开发应用程序，同时能够以一种不妨碍应用程序的方式处理故障和节能策略。

Wireless sensor networks are formed by inexpensive, underpowered, and rather unreliable wireless devices/nodes that are deployed in all kinds of environments to allow the remote acquisition of sensed data. Transmissions are expensive because they require a significant amount of the energy available to the nodes. To cope with this problem, sensed data, such as temperature, motion, pressure, etc. are collected and aggregated within the network, with the intention to reduce the total amount of data that needs to be eventually transmitted. Application programmers who wish to develop applications for wireless sensors networks need to be able to translate the application requirements into computation and communication tasks for each node. Yet, because of the limited resources of those nodes, they do not have the luxuries afforded by high-end computing devices that run fully capable operating systems. The question thus becomes what should be the minimum set of capabilities that would allow a wide range of applications to be developed, and are possible to incorporate in the limited resources of sensor nodes. At the same time, one should be able to properly and easily reason about the application logic. That is why the minimum set of capabilities should be accompanied by a model of computation and communication. In essence, the communication and computation model acts as the framework in which applications will be developed. Our proposal addresses precisely this issue, i.e., what abstractions and model for development of applications is suitable for wireless sensor nodes. We use our experience that spans from theoretical results to implementations of such networks. The proposal places emphasis on how to leverage the large number of sensor nodes to provide a "communal" form of resources over which an application can be developed, while at the same time being capable to deal with failures and energy saving strategies in a fashion that does not obstruct the applications.