Showing papers by "Robert M. Edwards published in 2021"

Experiments of an IoT-based wireless sensor network for flood monitoring in Colima, Mexico

Abstract: Urban flooding is one of the major issues in many parts of the world, and its management is often challenging. One of the challenges highlighted by the hydrology and related communities is the need for more open data and monitoring of floods in space and time. In this paper, we present the development phases and experiments of an Internet of Things (IoT)-based wireless sensor network for hydrometeorological data collection and flood monitoring for the urban area of Colima-Villa de Alvarez in Mexico. The network is designed to collect fluvial water level, soil moisture and weather parameters that are transferred to the server and to a web application in real-time using IoT Message Queuing Telemetry Transport protocol over 3G and Wi-Fi networks. The network is tested during three different events of tropical storms that occurred over the area of Colima during the 2019 tropical cyclones season. The results show the ability of the smart water network to collect real-time hydrometeorological information during extreme events associated with tropical storms. The technology used for data transmission and acquisition made it possible to collect information at critical times for the city. Additionally, the data collected provided essential information for implementing and calibrating hydrological models and hydraulic models to generate flood inundation maps and identify critical infrastructure.

A Propagation Study of LoRa P2P Links for IoT Applications: The Case of Near-Surface Measurements over Semitropical Rivers.

Abstract: Internet of Things (IoT) radio networks are becoming popular in several scenarios for short-range applications (e.g., wearables and home security) and medium-range applications (e.g., shipping container tracking and autonomous farming). They have also been proposed for water monitoring in flood warning systems. IoT communications may use long range (LoRa) radios working in the 915 MHz industrial, scientific and medical (ISM) band. In this research, we study the propagation characteristics of LoRa chirp radio signals close to and over water in a tropical meadow region. We use as a case study the Colima River in Mexico. We develop a novel point-to-point IoT measurement sounding system that does not require decoding of LoRa propriety bursts and provides accurate power versus distance profiles along the riparian zone of a steeply dropping mountain river. We used this system to obtain the measurements reported in this work, which are also analyzed and modeled. The results show that the LoRa signal propagation over water exhibits a log-normal distribution. As a result of the chirp signal processing, two new experimental path loss models are presented. The path loss results show a considerable degradation of the received signal power over water within vegetation and less signal degradation at antenna heights closer to the water surface.

Dynamic RFID Anti-collision Algorithm with Multiple Interrogators

Abstract: In dense radio frequency identification (RFID) situations where the coverage of multiple interrogators overlaps, a key challenge is to mitigate interrogator-involved collisions. Among the solutions that have been proposed to reduce or avoid such collisions, Geometric Distribution Reader Anti-collision (GDRA) protocol achieves the highest throughput exploiting Geometric distribution to minimise contention among interrogators. This approach is compatible with current RFID protocols, such as EPC Gen2, ISO18000-6C and ETSI EN 302 208–1 without extra hardware support. In this paper, based on GDRA, we propose an enhanced protocol, called Dynamic GDRA (DGDRA), in which different interrogators dynamically and independently adapt their own Geometric distributions based on the experienced number of successful transmissions and collisions. Simulation results confirm that the proposed DGDRA provides higher throughput and enhances fairness performance compared to the original anti-collision scheme.

XBee Latency Analysis for Drone Mounted Machine Control over Wireless Communication Channels

Abstract: In this paper, a method for the study XBee latency is researched. Study of an XBee radio link is important when considering machine control over wireless. Furthermore, knowledge of an XBee latency probability distribution is useful in the simulation of machine control over wireless. In this research, a camera gimble, typical of those used by expert observers with drones was proposed as the machine control activity. The test bed used was created using two XBee IEEE 802.15.4 MaxStream modules in a point to point configuration. In drone mounted machine control over an XBee channel a controller sends command messages to a flying drone. Lower latency in camera control yields shorter reaction times for camera operators and a more comfortable operation experience for untrained expert observers.