Usable and efficient abstractions for wireless sensor networks

无线传感器网络是由廉价的、功率不足的、相当不可靠的无线设备/节点形成的，这些设备/节点被部署在各种环境中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。为了科普这个问题，在网络内收集和聚合诸如温度、运动、压力等的感测数据，目的是减少最终需要传输的数据总量。希望开发无线传感器网络应用程序的应用程序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，它们没有运行完全功能的操作系统的高端计算设备所提供的奢侈品。因此，问题就变成了什么应该是最小的一组能力，将允许广泛的应用程序被开发，并有可能纳入有限的传感器节点资源。与此同时，人们应该能够正确和容易地推理应用程序逻辑。这就是为什么最低限度的能力应该伴随着一个计算和通信模型。从本质上讲，通信和计算模型充当了应用程序开发的框架。我们的建议正是针对这一问题，即，什么样的抽象和模型适合于无线传感器节点的应用开发。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，以提供一个“公共”的资源形式，可以开发一个应用程序，同时能够处理故障和节能策略的方式，不妨碍应用程序。

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.