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

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.

Flash Flood Early Warning System in Colima, Mexico.

This paper presents a system of sensors used in flash flood prediction that offers critical real-time information used to provide early warnings that can provide the minutes needed for persons to evacuate before imminent events. Flooding is one of the most serious natural disasters humans confront in terms of loss of life and results in long-term effects, which often have severely adverse social consequences. However, flash floods are potentially more dangerous to life because there is often little or no forewarning of the impending disaster. The Emergency Water Information Network (EWIN) offers a solution that integrates an early warning system, notifications, and real-time monitoring of flash flood risks. The platform has been implemented in Colima, Mexico covering the Colima and Villa de Alvarez metropolitan area. This platform consists of eight fixed riverside hydrological monitoring stations, eight meteorological stations, nomadic mobile monitoring stations called "drifters" used in the flow, and a sniffer with data muling capability. The results show that this platform effectively compiles and forwards information to decision-makers, government officials, and the general public, potentially providing valuable minutes for people to evacuate dangerous areas.

RiverCore: IoT Device for River Water Level Monitoring over Cellular Communications.

Flooding is one of the most frequent and costly natural disasters affecting mankind. However, implementing Internet of Things (IoT) technology to monitor river behavior may help mitigate or prevent future disasters. This article outlines the hardware development of an IoT system (RiverCore) and defines an application scenario in a specific hydrological region of the state of Colima (Mexico), highlighting the characteristics of data acquisition and data processing used. Both fixed position and moving drifter node systems are described along with web-based data acquisition platform developments integrated with IoT techniques to retrieve data through 3G cellular networks. The developed architecture uses the Message Queuing Telemetry Transport (MQTT) protocol, along with encryption and security mechanisms, to send real-time data packages from fixed nodes to a server that stores retrieved data in a non-relational database. From this, data can be accessed and displayed through different customizable queries and graphical representations, allowing future use in flood analysis and prediction systems. All of these features are presented along with graphical evidence of the deployment of the different devices and of several cellular communication and on-site data acquisition tests.

PlaIMoS: A Remote Mobile Healthcare Platform to Monitor Cardiovascular and Respiratory Variables.

The number of elderly and chronically ill patients has grown significantly over the past few decades as life expectancy has increased worldwide, leading to increased demands on the health care system and significantly taxing traditional health care practices. Consequently, there is an urgent need to use technology to innovate and more constantly and intensely monitor, report and analyze critical patient physiological parameters beyond conventional clinical settings in a more efficient and cost effective manner. This paper presents a technological platform called PlaIMoS which consists of wearable sensors, a fixed measurement station, a network infrastructure that employs IEEE 802.15.4 and IEEE 802.11 to transmit data with security mechanisms, a server to analyze all information collected and apps for iOS, Android and Windows 10 mobile operating systems to provide real-time measurements. The developed architecture, designed primarily to record and report electrocardiogram and heart rate data, also monitors parameters associated with chronic respiratory illnesses, including patient blood oxygen saturation and respiration rate, body temperature, fall detection and galvanic resistance.

Open-WiSe: a solar powered wireless sensor network platform.

Because battery-powered nodes are required in wireless sensor networks and energy consumption represents an important design consideration, alternate energy sources are needed to provide more effective and optimal function. The main goal of this work is to present an energy harvesting wireless sensor network platform, the Open Wireless Sensor node (WiSe). The design and implementation of the solar powered wireless platform is described including the hardware architecture, firmware, and a POSIX Real-Time Kernel. A sleep and wake up strategy was implemented to prolong the lifetime of the wireless sensor network. This platform was developed as a tool for researchers investigating Wireless sensor network or system integrators.

Formal specification and design techniques for wireless sensor and actuator networks.

A current trend in the development and implementation of industrial applications is to use wireless networks to communicate the system nodes, mainly to increase application flexibility, reliability and portability, as well as to reduce the implementation cost. However, the nondeterministic and concurrent behavior of distributed systems makes their analysis and design complex, often resulting in less than satisfactory performance in simulation and test bed scenarios, which is caused by using imprecise models to analyze, validate and design these systems. Moreover, there are some simulation platforms that do not support these models. This paper presents a design and validation method for Wireless Sensor and Actuator Networks (WSAN) which is supported on a minimal set of wireless components represented in Colored Petri Nets (CPN). In summary, the model presented allows users to verify the design properties and structural behavior of the system.

Do medical interns feel prepared to work in the COVID-19 pandemic?

OBJECTIVE To learn about the perceptions of medical internship students about the early conclusion of the course and their preparation to act in the fight against COVID-19. METHODS An online questionnaire was applied with questions about the socioeconomic profile and the object of investigation. The data were analyzed using the Bioestat 5.0 software. RESULTS 111 students participated, most of whom (61.3%) were male, aged 20 to 25 years (80.2%), of Catholic religion (57.5%), and attending the 2nd year of internship (50.5%). A small portion (22.5%) reported being in total social isolation. The majority (57.5%) considered themselves unprepared to act in the fight against the pandemic, and 86.8% of the students believe that the early conclusion of the course will contribute to the fight against COVID-19 in the country. CONCLUSION This scenario points to the urgency of measures that provide, to recent graduates, timely technical preparation, safe work conditions, and emotional support even at the beginning of their professional career, leading them to competent, dignified and healthy work, during and after the pandemic.

Do medical interns feel prepared to work in the COVID-19 pandemic?

SUMMARY OBJECTIVE To learn about the perceptions of medical internship students about the early conclusion of the course and their preparation to act in the fight against COVID-19. METHODS An online questionnaire was applied with questions about the socioeconomic profile and the object of investigation. The data were analyzed using the Bioestat 5.0 software. RESULTS 111 students participated, most of whom (61.3%) were male, aged 20 to 25 years (80.2%), of Catholic religion (57.5%), and attending the 2nd year of internship (50.5%). A small portion (22.5%) reported being in total social isolation. The majority (57.5%) considered themselves unprepared to act in the fight against the pandemic, and 86.8% of the students believe that the early conclusion of the course will contribute to the fight against COVID-19 in the country. CONCLUSION This scenario points to the urgency of measures that provide, to recent graduates, timely technical preparation, safe work conditions, and emotional support even at the beginning of their professional career, leading them to competent, dignified and healthy work, during and after the pandemic.

RESUMO OBJETIVO Conhecer as percepções de estudantes do internato médico sobre formatura antecipada e preparo para trabalhar no combate à pandemia da Covid-19. MÉTODOS Aplicou-se questionário on-line com questões sobre o perfil socioeconômico e o objeto de investigação. Os dados foram analisados pelo software Bioestat 5.0. RESULTADOS Participaram 111 estudantes, a maioria (61,3%) do sexo masculino, na faixa etária de 20 a 25 anos (80,2%), de religião católica (57,5%) e cursando o 2o ano do internato (50,5%). Pequena parcela (22,5%) informou estar em isolamento social total. A maioria (57,5%) se sente despreparada para atuar no combate à pandemia, e 86,8% consideram que a formatura antecipada contribuirá para o enfrentamento da Covid-19 no País. CONCLUSÃO Este panorama remete à urgência de medidas que propiciem, aos recém-graduados, preparo técnico oportuno, condições de trabalho seguras e suporte emocional já neste início de carreira profissional, conduzindo-os ao trabalho competente, digno e saudável, durante e após a pandemia.

Evaluación de Rendimiento del Protocolo MAC basado en CDMA Para Redes 802.11 / Performance evaluation of MAC Protocol Based on CDMA for Wireless 802.11 Networks / Avaliação do desempenho do protocolo MAC baseados em CDMA Para Redes 802.11

La popularidad de las redes inalámbricas 802.11 se basa en gran medida en el control de acceso al medio. Sin embargo, los retos que enfrenta esta tecnología en el acceso al medio son la interferencia y las colisiones provocadas por los usuarios dentro de la misma zona de cobertura, lo que resulta en un bajo rendimiento, a pesar de que se transmite con una tasa alta de transmisión, o en tener también un rendimiento bajo en el canal cuando se tienen pocos usuarios transmitiendo. Para resolver esta problemática se propone en este trabajo un protocolo que permite manejar dinámicamente las tasas de transmisión, logrando maximizar la cantidad de información transmitida con éxito (caudal eficaz). Se proponen dos esquemas; el primero toma en cuenta lo que sucede en el canal para aumentar o disminuir la tasa de transmisión y el segundo maneja una combinación óptima de tasas de transmisión. Los esquemas propuestos son validados mediante simulación y se demuestra que el protocolo propuesto con los dos esquemas puede obtener la adaptabilidad del tráfico en la red comparado con el mecanismo de acceso al medio tradicional con tasa fija.

The popularity of 802.11 wireless networks is based on the access control of the wireless medium. The greatest challenges this technology faces, however, are interference and collisions caused by users sharing the same coverage area. These two factors can result in a low throughput, even though the signal is transmitted at a high data transmission rate, or in low channel capacity when few users are transmitting. To solve these weaknesses, this work proposes a protocol that handles transmission rates dynamically to maximize the transmission success rate. Two schemes are proposed to address low throughput and low channel capacity. The first scheme dynamically monitors the channel in real time and increases or diminishes the transmission rate accordingly, while the second administers an optimal combination of transmission rates to minimize interference and collisions. Simulations show that the protocol improves traffic transmission in the network, as compared with fixed rated mechanisms used to access the wireless medium.

A popularidade das redes sem fio 802.11 se baseia em grande medida no controle de acesso ao meio. No entanto, os desafios que enfrenta esta tecnologia no acesso ao meio são a interferência e as colisões provocadas pelos usuários dentro da mesma zona de cobertura, o que resulta em um baixo rendimento, apesar de que se transmite com uma taxa alta de transmissão, ou em ter também um rendimento baixo no canal quando se tem poucos usuários transmitindo. Para resolver esta problemática se propõe neste trabalho um protocolo que permite manejar dinamicamente as taxas de transmissão, logrando maximizar a quantidade de informação transmitida com êxito (caudal eficaz). Propõem-se dois esquemas; o primeiro leva em conta o que sucede no canal para aumentar ou diminuir a taxa de transmissão e o segundo maneja uma combinação ótima de taxas de transmissão. Os esquemas propostos são validados mediante simulação e se demonstra que o protocolo proposto com os dois esquemas pode obter a adaptabilidade do tráfico na rede comparado com o mecanismo de acesso ao meio tradicional com taxa fixa.