Cost-Effective Optical Wireless Sensor Networks: Enhancing Detection of Sub-Pixel Transmitters in Camera-Based Communications.

In the domain of the Internet of Things (IoT), Optical Camera Communication (OCC) has garnered significant attention. This wireless technology employs solid-state lamps as transmitters and image sensors as receivers, offering a promising avenue for reducing energy costs and simplifying electronics. Moreover, image sensors are prevalent in various applications today, enabling dual functionality: recording and communication.

Optical Camera Communications in Healthcare: A Wearable LED Transmitter Evaluation during Indoor Physical Exercise.

This paper presents an experimental evaluation of a wearable light-emitting diode (LED) transmitter in an optical camera communications (OCC) system. The evaluation is conducted under conditions of controlled user movement during indoor physical exercise, encompassing both mild and intense exercise scenarios. We introduce an image processing algorithm designed to identify a template signal transmitted by the LED and detected within the image.

Soil Bacterial Diversity Responds to Long-Term Establishment of Perennial Legumes in Warm-Season Grassland at Two Soil Depths.

The introduction of rhizoma peanut (RP Benth) into bahiagrass ( Flüggé) may require time to develop stable plant-soil microbe interactions as the microbial legacy of the previous plant community may be long-lasting. A previous study showed that <2 years of introducing rhizoma peanut into bahiagrass pastures minimally affected soil bacterial diversity and community composition. In this study, we compared the effects of the long-term inclusion of rhizoma peanut (>8 years) into bahiagrass on soil bacterial diversity and community composition against their monocultures at 0 to 15 and 15 to 30 cm soil depths using next-generation sequencing to target bacterial 16S V3-V4 regions.

Application of Hydrothermal Time Models to Predict Sclerotial Germination of .

, causal agent of "southern blight" disease, is a soilborne fungal pathogen with a wide host range of more than 500 species. This study's objectives were to (i) quantify the effects of two environmental factors, temperature and soil moisture, on germination of inoculum (sclerotia), which is a critical event for the onset of disease epidemics and (ii) predict the timing of sclerotial germination by applying population-based threshold-type hydrothermal time (HTT) models. We conducted in vitro germination experiments with three isolates of isolated from peanuts, which were tested at five temperatures (), ranging from 17 to 40°C, four matric potentials (Ψ) between -0.

Soil Bacterial Communities Across Seven Rhizoma Peanut Cultivars (Arachis glabrata Benth.) Respond to Seasonal Variation.

Soil microorganisms play key roles in soil nutrient transformations and have a notable effect on plant growth and health. Different plant genotypes can shape soil microbial patterns via the secretion of root exudates and volatiles, but it is uncertain how a difference in soil microorganisms induced by crop cultivars will respond to short-term seasonal variations. A field experiment was conducted to assess the changes in soil bacterial communities of seven rhizoma peanut (Arachis glabrata Benth, RP) cultivars across two growing seasons, April (Spring season) and October (Fall season).

Empirical study of an underwater optical camera communication system under turbulent conditions.

This paper presents an experimental study of the turbulence impact caused by temperature inhomogeneity and air bubbles on a global shutter-based underwater optical camera communication (UOCC). The effects of these two phenomena on UOCC links are illustrated in terms of the intensity variations and an associated reduction in the average received intensity of the illuminated pixels corresponding to the optical source projection and the dispersion of the projection on the captured images. Additionally, it is shown that the area of illuminated pixels in the temperature-induced turbulence scenario is higher than in the bubbly water case.

General framework for calculating irradiance distributions of symmetric surface sources.

Symmetries in system modeling can be exploited to obtain analytical results on the system behavior and to speed up computations using the symmetric model. This work explores the use of symmetries in radiant surfaces for calculating the induced irradiance distributions by developing a general mathematical expression. The obtained model is applied to flat, cylindrical, and spherical sources to obtain explicit expressions.

Deep learning for signal clock and exposure estimation in rolling shutter optical camera communication.

In rolling shutter (RS)-based optical camera communication (OCC) links, selecting the appropriate camera's exposure time is critical, as it limits the reception bandwidth. In long exposures, the pixels accumulate over time the incoming irradiance of several consecutive symbols. As a result, a harmful intersymbol interference corrupts the received signal.

Clustering-based data detection for spectral signature multiplexing in multispectral camera communication.

Optical camera communication (OCC) is a promising technology to be used in future wireless communication systems. In this work, a cluster-based data detection procedure is applied to enhance the performance of an OCC system. A multispectral camera is employed to capture the spectral variations in light-emitting diodes (LEDs) caused by temperature.

VLC Network Design for High Mobility Users in Urban Tunnels.

Current vehicular systems require real-time information to keep drivers safer and more secure on the road. In addition to the radio frequency (RF) based communication technologies, Visible Light Communication (VLC) has emerged as a complementary way to enable wireless access in intelligent transportation systems (ITS) with a simple design and low-cost deployment. However, integrating VLC in vehicular networks poses some fundamental challenges.

Soil bacterial community response to rhizoma peanut incorporation into Florida pastures.

Incorporating legumes is one option for improving pasture fertility, sustainability, and biodiversity. Diazotrophic microorganisms, including rhizobia that form symbioses with legumes, represent a small fraction of the total soil microbial community. Yet, they can offset nitrogen (N) fertilizer inputs through their ability to convert atmospheric N into plant-usable N via biological N fixation (BNF).

Convolutional autoencoder for exposure effects equalization and noise mitigation in optical camera communication.

In rolling shutter-based optical camera communication (OCC), the camera's exposure time limits the achievable reception bandwidth. In long-exposure settings, the image sensor pixels average the incident received power, producing inter-symbol interference (ISI), which is perceived in the images as a spatial mixture of the symbol bands. Hence, the shortest possible exposure configuration should be selected to alleviate ISI.

Survey on Optical Wireless Communications-Based Services Applied to the Tourism Industry: Potentials and Challenges.

In this paper, we explore the potential applications of Optical Wireless Communications in the tourism industry, considering both indoor and outdoor scenarios and different transmission speeds. They range from high-speed atmospheric outdoor links (Free-Space Optics (FSO)) to indoor systems based on high-speed lighting networks (known under the trade name LiFi©) or low-speed services support the Internet of Things networks, using visible light (VLC) or IR emitters, with receivers based on either on classical photodiodes or in image sensors, known as Optical Camera Communications. The avant-garde applications of this technology have been studied focusing on three possible use scenarios: the traveler himself, in what we have called TAN (Tourist Area Network); the tourist facility, which includes not only the hotel but also leisure areas (theme parks, museums, natural protected areas) or services (restaurants, shopping areas, etc.

Wireless Sensor Networks Using Sub-Pixel Optical Camera Communications: Advances in Experimental Channel Evaluation.

Optical wireless communications in outdoor scenarios are challenged by uncontrollable atmospheric conditions that impair the channel quality. In this paper, different optical camera communications (OCC) equipment are experimentally studied in the laboratory and the field, and a sub-pixel architecture is raised as a potential solution for outdoor wireless sensor networks (WSN) applications, considering its achievable data throughput, the spatial division of sources, and the ability of cameras to overcome the attenuation caused by different atmospheric conditions such as rain, turbulence and the presence of aerosols. Sub-pixel OCC shows particularly adequate capabilities for some of the WSN applications presented, also in terms of cost-effectiveness and scalability.

Design and Experimental Characterization of a Discovery and Tracking System for Optical Camera Communications.

Visible light communications (VLC) technology is emerging as a candidate to meet the demand for interconnected devices' communications. However, the costs of incorporating specific hardware into end-user devices slow down its market entry. Optical camera communication (OCC) technology paves the way by reusing cameras as receivers.

Optical Camera Communication as an Enabling Technology for Microalgae Cultivation.

Optical Camera Communication (OCC) systems have a potential application in microalgae production plants. In this work, a proof-of-concept prototype consisting of an artificial lighting photobioreactor is proposed. This reactor optimises the culture's photosynthetic efficiency while transmitting on-off keying signals to a rolling-shutter camera.

Sandstorm effect on experimental optical camera communication.

Sandstorms can severely affect the reliability of outdoor optical wireless communications (OWC) by diminishing large regions' visibility. In this work, the effect of a real sandstorm on optical camera communications (OCC) links is experimentally evaluated. Two link ranges are essayed using a cost-efficient telescope-based camera setup with commercial LEDs.

MAC/PHY Comprehensive Visible Light Communication Networks Simulation.

In this paper, the effect of channel conditions on the global behavior of a wireless Visible Light Communications (VLC) optical network are studied. It presents a system-level simulator that considers jointly a channel propagation model and the MAC mechanisms to have a realistic description of the network, even in situations where the emitted signal is heavily affected by reflections in any close surface or obstacle. The resulting platform also accurately evaluates both Line-Of-Sight (LOS) and Non-LOS (NLOS) contributions on each node and enables the effective use of Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) schemes as defined by IEEE 802.

Characterization and Performance of a Thermal Camera Communication System.

This work presents a novel communications technology named Thermal Camera Communication (TCC), which is analogous to Optical Camera Communication (OCC). Thermographic cameras and Peltier cells are proposed as receiver and transmitter, respectively, changing completely their usual field of application. Furthermore, a comprehensive characterization of the Peltier-Thermal camera pair is carried out, presenting their bandwidth, achievable data rate under On-Off-Keying (OOK) modulation, noise characteristics, and energy efficiency.

Improved Protocol for DNA Extraction from Subsoils Using Phosphate Lysis Buffer.

As our understanding of soil biology deepens, there is a growing demand for investigations addressing microbial processes in the earth beneath the topsoil layer, called subsoil. High clay content in subsoils often hinders the recovery of sufficient quantities of DNA as clay particles bind nucleic acids. Here, an efficient and reproducible DNA extraction method for 200 mg dried soil based on sodium dodecyl sulfate (SDS) lysis in the presence of phosphate buffer has been developed.

Effect of moving microalgae on underwater wireless optical links.

Underwater wireless optical communications is a promising technique for addressing short-range data networks, as it provides cost, performance, and complexity improvements as compared with other alternatives, such as acoustic communications or radio frequency links. It is a part of the optical wireless communications research area, since for these applications, broad optical sources such as visible LED lamps can be used. Unless those links are designed for short distances (about 1 m, as in data-muling services on internet-of-things submerged systems), they are still severely affected by channel perturbations, such as scattering due to the presence of particles.

Hybrid RF/VLC Network Architecture for the Internet of Things.

In recent years, there has been a remarkable advance in monitoring technologies in many environments, be they urban or rural. These technologies, included in the Internet of Things (IoT) domain, allow remote control and acquisition of data from sensors for their subsequence analysis. All these systems are based on the interaction between sensors and actuators.

Correlation-based receiver for optical camera communications.

In color-multiplexed optical camera communications (OCC) systems, data acquisition is restricted by the image processing algorithm capability for fast source recognition, region-of-interest (ROI) detection and tracking, packet synchronization within ROI, estimation of inter-channel interference and threshold computation. In this work, a novel modulation scheme for a practical RGB-LED-based OCC system is presented. The four above-described tasks are held simultaneously.

Validation study of a scale for assessing three personality functional dimensions among Venezuelan HIV-positive patients.

Background: Personality has been recognized as a key variable in the prediction of treatment adherence and health care behaviors in patients living with chronic diseases.

Purpose: In order to contribute to the prediction of treatment-adherence behaviors among HIV-positive patients, this study aimed to test the metric properties of the 12-item Stress-Related Situations Scale (SRSS-12), which assesses four interactive styles of personality related to stressful situations when receiving treatment for a chronic disease.

Patients And Methods: This cross-sectional study was performed with a nonprobability sampling between May and June 2016.