In 2013, the International Agency for Research on Cancer classified particulate matter (PM) as carcinogenic to humans. It is therefore essential to measure PM concentrations to minimize the exposure of individuals. Our objective was to investigate personal exposure to PM2.5 (PM with diameter <= 2.5 mu m) in Grenoble (France) during commuting in different transportation modes: bike, walk, bus and tramway. PM2.5 measurements were found to be the highest for bikes, followed by walk, bus, and tramway. In this study, conducted in spring during low pollution levels of PM, exposure levels are greatly influenced by the time of day. Pedestrian and cyclists' exposure generally stayed under background reference values. Exposure in public transportation was usually below reference values, but when background PM2.5 levels went lower (evening), levels registered in the tramway or bus reached those of the reference. Therefore, public transport users could be less exposed than active commuters, except when ambient pollutant levels are low. Environmental parameters like wind might be important in Grenoble, and it would be worthwhile to reproduce this study at a time when wind speed is lower.
This paper proposes two different approaches to be applied in gateway placement problem in LoRaWAN sensor networks. The first approach is based on finding the minimal set to contain all the coverage intersections of the sensors and the second approach is based on optimization via integer programming over the distance between the gateways and sensors. Our results show that using automated gateway placement provides significantly less number of gateways to be used.
Considering the ongoing growth of Wireless Sensor Networks (WSNs) and the challenges they pose due to their hardware limitations as well as the intrinsic complexity of their interactions, specialized algorithms have the potential to help solving these challenges. We present a survey on recent developments regarding algorithmic problems which have applications in wireless systems and WSNs in particular. Focusing on the intersection between WSNs and algorithms, we give an overview of recent results inside this intersection, concerning topics such as routing, interference minimization, latency reduction, localization among others. Progress on solving these problems could be potentially beneficial for the industry as a whole by increasing network throughput, reducing latency or making systems more energy-efficient. We summarize and structure these recent developments and list interesting open problems to be investigated in future works.
