以單一節點釋放的感測

Abstract

An important problem in wireless sensor networks (WSNs) is how to scale down the amount of human effort in deploying and maintaining a WSN infrastructure. This is because human effort often hinders the successful long-term deployment of a WSN. Placing new sensors and replacing existing sensors often require humans to go on-site. The cost of this human effort can be prohibitive when a WSN is deployed in the wild. This dissertation introduces the concept of a single-release point sensing method for mobile sensors with the aim of reducing to reduce the human effort required to deploy and maintain a WSN infrastructure. This single-release point sensing method enables the automated deployment of mobile sensors and the automated replacement of battery-depleted (or faulty) sensors. This dissertation demonstrates the feasibility and benefits of single-release point sensing by developing two successive systems for pipeline monitoring applications. First, we designed and implemented PipeProbe, which is a mobile sensor system for mapping the 3D spatial topology of hidden water pipelines behind walls. PipeProbe works by releasing a sensor node from a single point of water inlet. The flowing water carries the node through the entire pipeline infrastructure. By gathering data from a water pressure sensor, 3D accelerometer, and 3D gyroscope, PipeProbe can reconstruct the hidden layout of the pipeline. However, human effort is required to release sensor at the single point of water inlet and retrieve the sensor at the water outlet. Second, we designed and implemented TriopusNet, which is a system that automates WSN deployment and replacement in pipeline monitoring. This system works by releasing multiple sensor nodes from a single water inlet until the nodes cover the entire pipeline. Each node in TriopusNet consists of a latching mechanism that allows the nodes to automatically latch themselves inside the pipeline. This study also presents a placement algorithm to determine when and where to place sensors, and designs a replacement algorithm to replace the nodes when the node runs out of battery. These hardware prototype and algorithms can dramatically reduce the human effort required by pipeline monitoring. Finally, we extensively evaluated the proposed systems by building a real testbed and conducting real test scenarios to determine the feasibility of the single-release point sensing method.