An Availability Metric and Optimization Algorithms for Simultaneous Coverage of Targets and Areas by Wireless Visual Sensor Networks The maturation of Wireless Visual Sensor Networks (WVSN) in the last years, with new communication technologies and continuous releasing of embedded hardware development platforms, has significantly enlarged the number and relevance of visual monitoring applications, better supporting smart city and Internet of Things initiatives. However, there are still several challenges to be addressed, especially when visual sensors are used for critical monitoring. When availability issues are addressed in WVSN, different metrics and algorithms can be employed, but such approaches are usually focused on a single coverage goal. Actually, some monitoring applications may want to simultaneously optimize coverage over targets and areas alike, which requires an appropriate perception of the level of availability of the application at any given time. In this context, this article proposes a new availability metric for WVSN, considering that all targets and areas should be optimally and simultaneously covered by the cameras. In addition, optimization algorithms are proposed and compared, aiming at improving the availability of applications when rotatable visual sensors are employed.

Wireless visual sensor networks redeployment based on dependability optimization Wireless visual sensor networks (WVSN) bring a more comprehensive perception of monitored environments, leading to an increase adoption of such networks as a promising solution for a wide range of applications. Among many examples, highlight industrial applications related to the industry 4.0 paradigm, which increasingly require more data from manufacturing systems. Those sensorbased applications are in many cases safetycritical, requiring dependability guarantees mainly related with reliability and availability, that should be maintained during the whole network operation. Although several approaches have provided network deployment with dependability guarantees, sometimes the monitored environment or the application configurations can change during the network operation, which can violate the dependability requirements and demand network redeployment in order to keep those guarantees. In this paper we propose a novel algorithm to redeploy WVSN guided by the optimization of the application dependability, considering changes on camerasxe2x80x99 orientations. A methodology is defined to support dependability analysis. We compare the results of the proposed algorithm with previous algorithms found in literature. The achieved results show that the proposed algorithm is useful and efficient to provide network redeployment, keeping or improving the application dependability.