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A main challenge in deploying wireless sensor networks (WSNs) is determining the minimum quantity of sensor nodes required to fully cover the region of interest while avoiding coverage holes. This study proposes a method to compute the number of nodes needed to monitor a circular region and a distributed control strategy based on circular formations to move dynamic agents to their desired positions. The method addresses the coverage problem, ensuring that each point in the monitored region is detected without losing connectivity. In addition, the study compares this approach with a sensor node allocation method based on Voronoi diagrams, highlighting the need for an algorithm that computes the desired positions of the agents to provide guaranteed flawless coverage; the proposed method achieves this by obtaining the desired final positions. The hybrid WSN architecture, together with the proposed method, achieves full coverage efficiently and better utilizes the detection circumference of sensors compared to traditional rectangular monitoring regions.

Non-standard diesel blends can be harmful to the environment and human health. In this context, a simple analytical method to estimate the biodiesel mixture ratio in diesel was developed based on impedance spectroscopy (IS) associated with interdigitated sensors. In this article, four different interdigitated sensors with varied comb spacing (G) were simulated using the COMSOL Multiphysics software. Based on finite element simulations, four interdigitated electrode architectures were manufactured and evaluated. The best geometry was chosen according to theoretical data simulations, and its interdigitated electrodes were manufactured for the compositional evaluation of pseudo-binary biodiesel–diesel mixtures. According to the X-ray powder diffraction technique, the deposition of the conductive layer (Au0) over the surface of the dielectric substrate (SiO2) did not alter its phase composition. In the analysis of AFM and SEM, it was possible to observe irregular edges on the electrodes, possibly related to the manufacturing process of the thin layers and mechanical stability. Another characteristic observed in the AFM images was the height of the step of the gold layer of the sensor. Several cross sections were obtained, and the mean step value was 225.71 ± 0.0032 nm. Although there were differences in the roughness, the whole sensor had nanometric roughness. Based on the finite element method simulation performed, it can be assumed that the geometric parameters more suitable for the manufacturing of the electrode are W = 20 µm, L = 1000 µm, G = 50 µm, and N = 40 digits. The electrical characterization performed by impedance spectroscopy showed that we could differentiate between biodiesel and diesel fuels and their pseudo-binary mixtures in the low-frequency region.

In this paper, a bioinspired method in the magnetic field memory of the bees, applied in a rover of precision pollination, is presented. The method calculates sharpness features by entropy and variance of the Laplacian of images segmented by color in the HSV system in real-time. A complementary positioning method based on area feature extraction between active markers was developed, analyzing color characteristics, noise, and vibrations of the probe in time and frequency, through the lateral image of the probe. From the observed results, it can be seen that the unsupervised method does not require previous calibration of target dimensions, histogram, and distances involved in positioning. The algorithm showed less sensitivity in the extraction of sharpness characteristics regarding the number of edges and greater sensitivity to the gradient, allowing unforeseen operation scenarios, even in small sharpness variations, and robust response to variance local, temporal, and geophysical of the magnetic declination, not needing luminosity after scanning, with the two freedom of degrees of the rotation.

Considerando que o crescimento das atividades aeroespaciais esbarra em questões relacionadas ao desenvolvimento sustentável e tensões geopolíticas, esse artigo tem o objetivo de investigar os desafios ambientais associados às atividades espaciais, com foco na gestão de material residual e no impacto das atividades espaciais comerciais no meio ambiente da Terra e do espaço sideral. Para tanto, procede-se em um levantamento da literatura com enfoque em artigos publicados sobre a temática nos últimos cinco anos. Desse modo, compreende-se que a Indústria Aeroespacial ainda não está efetivamente posicionada como alinhada ao desenvolvimento sustentável, principalmente devido à geração de resíduos espaciais. Esse material residual pode causar impactos em alguma nação da Terra, desencadeando tensões geopolíticas. Diante disso, a discussão sobre os desafios ambientais e a sustentabilidade no cenário aeroespacial na perspectiva geopolítica é transdisciplinar e deve ser continuamente aprofundada para gerar estratégias em diferentes contextos.

In wireless sensor networks (WSNs), coverage is an essential performance metric for monitoring delimited regions, with the allocation of sensor nocles being a critical problem for ensuring full coverage. This paper addresses the optimal allocation of mobile sensor nodes based on optimal control techniques, proposing a solution to the allocation problem, considering that the number of available nodes is sufficiënt to achieve full coverage. The proposed methods and algorithms for optimally allocating dynamic sensor nodes provide flawless coverage and without loss of connectivity among nodes. Based on the angular velocity of the agents, a coverage control scheme is developed, with the displacement to the specified position guaranteed by the discrete linear quadratic tracker (DLQT) and this position maintained by means of the discrete linear quadratic regulator (DLQR), in order to reduce the arrival time and residence time, respectively, in the angular position. In this scheme, the monitoring region is a delimited circle, with a static sensor node at its center. The mobile sensor nodes are positioned on a displacement circle with a radius smaller than that of the monitored region. The order of these dynamic agents along the circle is preserved to avoid collisions. Finally, the results presented indicate that the network topology, its modelling, and the proposed controller are efficiënt for application in monitoring hostile environments, providing greater network reliability.

Oriented to detect and classify fuels in coastal areas, a methodology for designing a smart sensor device, based on the IEEE 1451 standard and decision tree, is presented in this article. The physical elements of the proposed device are sensors for signal acquisition, and a microcontroller for processing, classifi cation and communication. The software elements of smart sensor are the classification algorithm and communication protocol. Signals captured by the sensors include hydrogen potential, turbidity, temperature, pressure, location and colors. The microcontroller process these signal that are used to detect and classify the presence of polluting fuels in the water. Additionally, the smart sensors are encapsulated to prevent damage caused by the deteriorating characteristics of fuels. For monitoring and evaluation purposes, the signals/data and classifications are sent to a cloud using Internet of Things (IoT) techniques, and monitored using ThingSpeak®. The performance of the smart sensor was evaluated in the laboratory using appropriate materials. The measurement and classification tests were conducted using containers with solutions of water and fuel.

Thermal comfort, luminosity, and air quality are factors that directly impact the health, \"well-being, and cognitive performance of occupants in an indoor environment. It is crucial that ergonomic parameters such as temperature, humidity, light levels, and carbon dioxide concentration in these spaces adhere to criteria established by Brazilian standards. Addressing this issue, this study presents a methodology for developing a Wireless Sensor Network (WSN) with the objective of intelligently monitoring and classifying the environmental quality of study spaces. The WSN nodes comprise signal acquisition sensors, a microcontroller for processing, classification, and communication, and a multiplexer serving as an analog input expander for the microcontroller. The software components include signal processing, communication and classification algorithms that use machine learning approaches. To enable remote monitoring, the collected signals and classifications are transmitted and stored in a cloud infrastructure that uses Internet of Things (IoT) and cloud computing techniques.

Maritime transport is of great economic importance due to the increasing global industrialization. The importance of environmental issues, such as oil spills on the ocean surface, has been widely studied, leading to the need for methods to solve this problem. With the availability of satellites equipped with Synthetic Aperture Radar (SAR), it is possible to work on the monitoring for detection and classification oil spills and its derivatives at ocean surface. In this work, based on deep learning approach, the detection and classification is performed via YOLOv8 family algorithms. According to the tests carried out for YOLOv8 nano, small and medium, the best performance was obtained for medium algorithm, with accuracy and mAP-50 and mAP50-90 in the validation phase equivalent to 0.891%, 0.85% and 0.716%, respectively. In the test phase, it achieved a confidence level of over 70%o of the objects detected.

Considering that the growth of aerospace activities is hampered by issues related to sustainable development and geopolitical tensions, this article aims to investigate the environmental challenges associated with space activities, focusing on the management of waste material and the impact of commercial space activities on the environment of Earth and outer space. To this end, a literature review was conducted, focusing on articles published on the subject in the last five years. Thus, it is understood that the Aerospace Industry is not yet effectively positioned as aligned with sustainable development, due to the generation of space waste. This waste material can cause impacts on some nation on Earth, triggering geopolitical tensions. In view of this, the discussion on environmental challenges and sustainability in the aerospace scenario from a geopolitical perspective is transdisciplinary and must be continually deepened to generate strategies in different contexts. Keywords: Aerospace Industry. Outer Space. Geopolitics. Sustainability. Considerando que o crescimento das atividades aeroespaciais esbarra em questoes relacionadas ao desenvolvimento sustentavel e tensoes geopoliticas, esse artigo tem o objetivo de investigar os desafios ambientais associados as atividades espaciais, com foco na gestao de material residual e no impacto das atividades espaciais comerciais no meio ambiente da Terra e do espaco sideral. Para tanto, procede-se em um levantamento da literatura com enfoque em artigos publicados sobre a tematica nos ultimos cinco anos. Desse modo, compreende-se que a Industria Aeroespacial ainda nao esta efetivamente posicionada como alinhada ao desenvolvimento sustentavel, principalmente devido a geracao de residuos espaciais. Esse material residual pode causar impactos em alguma nacao da Terra, desencadeando tensoes geopoliticas. Diante disso, a discussao sobre os desafios ambientais e a sustentabilidade no cenario aeroespacial na perspectiva geopolitica e transdisciplinar e deve ser continuamente aprofundada para gerar estrategias em diferentes contextos. Palavras-chave: Industria Aeroespacial. Espaco Exterior. Geopolitica. Sustentabilidade. Considerando que el crecimiento de las actividades aeroespaciales choca con cuestiones relacionadas con el desarrollo sostenible y tensiones geopoliticas, este articulo tiene como objetivo investigar los desafios ambientales asociados con las actividades espaciales, centrandose en la gestion de materiales de desecho y el impacto de las actividades espaciales comerciales en el medio ambiente de la Tierra y el espacio sideral. Para ello se realiza un levantamiento bibliografico centrado en articulos publicados sobre el tema en los ultimos cinco anos. Por tanto, se entiende que la Industria Aeroespacial aun no esta efectivamente posicionada como alineada con el desarrollo sostenible, debido principalmente a la generacion de residuos espaciales. Este material residual puede provocar impactos en alguna nacion de la Tierra, desencadenando tensiones geopoliticas. Ante esto, la discusion sobre los desafios ambientales y la sostenibilidad en el escenario aeroespacial desde una perspectiva geopolitica es transdisciplinaria y debe profundizarse continuamente para generar estrategias en diferentes contextos. Palabras clave: Industria Aeroespacial. Espacio al Aire Libre. Geopolitica. Sostenibilidad.