We propose an on-line fault detection and diagnosis framework in sensor networks, called Inspect, which is based on a hybrid tiered approach to integrity checking. Inspect tiered design, combines the benefits of distributed and centralized approaches, thus improving the responsiveness and efficiency of the fault detection. More precisely, Inspect consists of a local tier built at each sensor node and capable of detecting anomalies, and a centralized tier built at the sink and capable of distinguishing between sensor faults and unexpected temporal-spatial variations in the phenomenon, and detecting more complex types of faults.

Inspects offers several desirable features: it provides online detection, it is not designed for a specific application or statistical distribution of the phenomenon, and it is more robust to temporal-spatial variations of the phenomenon. Moreover, Inspect provides confidence bounds that can be dynamically tuned according to the user requirements for a better resource management, and addresses the problem of detecting more complex types of faults, which is a challenging and yet unexplored problem.

Wireless sensor networks (WSNs) are a relatively new and rapidly developing technology; they have a wide range of applications including environmental monitoring, agriculture, and public health. Shared technology is a common usage model for technology adoption in developing countries. WSNs have great potential to be utilized as a shared resource due to their on-board processing and ad-hoc networking capabilities, however their deployment as a shared resource requires that the technical community first address several challenges. The main challenges include enabling sensor portability—the frequent movement of sensors within and between deployments, and rapidly deployable systems—systems that are quick and simple to deploy. We first discuss the feasibility of using sensor networks as a shared resource, and then describe our research in addressing the various technical challenges that arise in enabling such sensor portability and rapid deployment. We also outline our experiences in developing and deploying water quality monitoring wireless sensor networks in Bangladesh and California.