Powering Sigfox nodes with harvested energy

Sigfox is one of the popular LPWAN technologies used in the Internet of Things. As in the case of many other wireless protocols, Sigfox nodes are mainly powered with batteries, which leads to important maintenance costs and slows down its acceptance. Enabling such systems to work on harvested energy will facilitate their use and acceptance. We designed and tested a Sigfox node that can be powered by a 1 cm2 solar cell, opening the door to further optimization in size and costs. Preliminary tests made at the window of one of our office show that one can transmit tens of message per day with that node

Low light energy autonomous LoRaWAN node

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A LoRaWAN node powered using an 8 cm2 solar cell was designed and its low light harvesting performance evaluated. The embedded system is used to sense some parameters and transmit the results every 10 minutes, using the spreading factor SF7BW125 and transmitting with + 8 dBm, which allows the coverage of a small building. The node can cold start with less than 30 lux. Once started, its operations can be sustained down to 20 lux. Operation at higher spreading factors or higher RF output power is also possible if the transmission interval is increased. Such a performance enables the use of energy autonomous LPWAN nodes in poorly lit environments. The small size of the solar cell makes it possible to build small nodes

Energy autonomous wireless sensing node working at 5 Lux from a 4 cm2 solar cell

Harvesting energy for IoT nodes in places that are permanently poorly lit is important, as many such places exist in buildings and other locations. The need for energy-autonomous devices working in such environments has so far received little attention. This work reports the design and test results of an energy-autonomous sensor node powered solely by solar cells. The system can cold-start and run in low light conditions (in this case 20 lux and below, using white LEDs as light sources). Four solar cells of 1 cm2 each are used, yielding a total active surface of 4 cm2. The system includes a capacitive sensor that acts as a touch detector, a crystal-accurate real-time clock (RTC), and a Cortex-M3-compatible microcontroller integrating a Bluetooth Low Energy radio (BLE) and the necessary stack for communication. A capacitor of 100 μF is used as energy storage. A low-power comparator monitors the level of the energy storage and powers up the system. The combination of the RTC and touch sensor enables the MCU load to be powered up periodically or using an asynchronous user touch activity. First tests have shown that the system can perform the basic work of cold-starting, sensing, and transmitting frames at +0 dBm, at illuminances as low as 5 lux. Harvesting starts earlier, meaning that the potential for full function below 5 lux is present. The system has also been tested with other light sources. The comparator is a test chip developed for energy harvesting. Other elements are off-the-shelf components. The use of commercially available devices, the reduced number of parts, and the absence of complex storage elements enable a small node to be built in the future, for use in constantly or intermittently poorly lit places

Depression, anxiety and stress among alcohol addicts

Objective. The aim of the study was to examine the level of depression, anxiety and stress in alcohol addicts, i.e. to determine differences in the level of depression, anxiety and stress between the group of subjects diagnosed with F10.1 and the group of subjects diagnosed with F10.2, as well as to determine differences in sociodemographic characteristics and health status between the groups of subjects diagnosed with F10.1 and F10.2. Methods. Our study was designed as a non-experimental, observational cross-sectional study. It was conducted at the University Clinical Centre Kragujevac in the Clinic for Psychiatry, during January 2021. The sample consisted of 110 respondents of both sexes, aged 18 to 65, divided into two groups. The first group consisted of subjects diagnosed with alcohol dependence (F10.2), and the second group consisted of subjects diagnosed with alcohol abuse (F10.1). Results. Our study has shown that alcohol addicts have clinically significant and severe symptoms of depression, that symptoms were positively correlated with stress levels, and that short-term stress of milder intensity was associated with occasional alcohol abuse, while prolonged stress was a predictor of alcohol dependence. No statistically significant association of alcohol dependence and alcohol abuse with anxiety was found. It was also found that alcohol dependence is associated with certain sociodemographic characteristics such as gender and marital status, education level, employment status, as well as health status and the number of hospitalizations.Conclusion. With this study, we have shown how much stress is present and important in the genesis of alcoholism, as well as the positive correlation of depression and alcohol dependence, and the importance of sociodemographic characteristics in their genesisPublishe

Identifying drivers of non-stationary climate-growth relationships of European beech

The future performance of the widely abundant European beech (Fagus sylvatica L.) across its ecological amplitude is uncertain. Although beech is considered drought-sensitive and thus negatively affected by drought events, scientific evidence indicating increasing drought vulnerability under climate change on a cross-regional scale remains elusive. While evaluating changes in climate sensitivity of secondary growth offers a promising avenue, studies from productive, closed-canopy forests suffer from knowledge gaps, especially regarding the natural variability of climate sensitivity and how it relates to radial growth as an indicator of tree vitality. Since beech is sensitive to drought, we in this study use a drought index as a climate variable to account for the combined effects of temperature and water availability and explore how the drought sensitivity of secondary growth varies temporally in dependence on growth variability, growth trends, and climatic water availability across the species’ ecological amplitude. Our results show that drought sensitivity is highly variable and non-stationary, though consis- tently higher at dry sites compared to moist sites. Increasing drought sensitivity can largely be explained by increasing climatic aridity, especially as it is exacerbated by climate change and trees’ rank progression within forest communities, as (co-)dominant trees are more sensitive to extra-canopy climatic conditions than trees embedded in understories. However, during the driest periods of the 20th century, growth showed clear signs of being decoupled from climate. This may indicate fundamental changes in system behavior and be early-warning signals of decreasing drought tolerance. The multiple significant interaction terms in our model elucidate the complexity of European beech’s drought sensitivity, which needs to be taken into consideration when assessing this species’ response to climate change.Additional authors: Isabel Dorado-Liñán, Choimaa Dulamsuren, Balázs Garamszegi, Michael Grabner, Andrew Hacket-Pain, Jon Kehlet Hansen s, Claudia Hartl, Weiwei Huang, Pavel Janda, Marko Kazimirović, Florian Knutzen, Jürgen Kreyling, Alexander Land, Nicolas Latte, François Lebourgeois, Christoph Leuschner, Luis A. Longares, Edurne Martinez del Castillo, Annette Menzel, Renzo Motta, Lena Muffler-Weigel, Paola Nola, Momchil Panayatov, Any Mary Petritan, Ion Catalin Petritan, Ionel Popa, Cǎtǎlin-Constantin Roibu , Álvaro Rubio-Cuadrado, Miloš Rydval, Tobias Scharnweber, J. Julio Camarero, Miroslav Svoboda, Elvin Toromani, Volodymyr Trotsiuk, Marieke van der Maaten-Theunissen, Ernst van der Maaten, Robert Weigel, Martin Wilmking, Tzvetan Zlatanov, Anja Rammig, Christian S. Zan

Schimke immunoosseous dysplasia: defining skeletal features

Schimke immunoosseous dysplasia (SIOD) is an autosomal recessive multisystem disorder characterized by prominent spondyloepiphyseal dysplasia, T cell deficiency, and focal segmental glomerulosclerosis. Biallelic mutations in swi/snf-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1 (SMARCAL1) are the only identified cause of SIOD, but approximately half of patients referred for molecular studies do not have detectable mutations in SMARCAL1. We hypothesized that skeletal features distinguish between those with or without SMARCAL1 mutations. Therefore, we analyzed the skeletal radiographs of 22 patients with and 11 without detectable SMARCAL1 mutations. We found that patients with SMARCAL1 mutations have a spondyloepiphyseal dysplasia (SED) essentially limited to the spine, pelvis, capital femoral epiphyses, and possibly the sella turcica, whereas the hands and other long bones are basically normal. Additionally, we found that several of the adolescent and young adult patients developed osteoporosis and coxarthrosis. Of the 11 patients without detectable SMARCAL1 mutations, seven had a SED indistinguishable from patients with SMARCAL1 mutations. We conclude therefore that SED is a feature of patients with SMARCAL1 mutations and that skeletal features do not distinguish who of those with SED have SMARCAL1 mutations

Iterative Lösung eines zweidimensionalen Ruinproblems

Arbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprüftAbweichender Titel nach Übersetzung der Verfasserin/des VerfassersIn der vorliegenden Arbeit geht es um die Anwendung und numerische Umsetzung der Policy-Iterationsmethode auf ein zweidimensionales stochastisches Kontrollmodell mit zwei unabhängigen Brownschen Bewegungen, die das Verhalten von zwei Firmen auf einem Markt beschreiben, wie es in dem Artikel von McKean und Shepp [18] vorgestellt wurde. Im Artikel wurde nachgewiesen, dass die gewählte Strategie, anhand derer die Unternehmen durch den Staat in Form von Steuererleichterungen gefördert werden, je nach Optimierungskriterium variiert. Dabei stellt sich heraus, dass, wenn das Ziel darin besteht, die gemeinsame Überlebenswahrscheinlichkeit beider Unternehmen zu maximieren, die Push-Bottom Strategie, d.h. die Strategie, die das schwächere Unternehmen zum betrachteten Zeitpunkt unterstützt, die optimale Strategie ist. Besteht das Kriterium hingegen in der Maximierung der erwarteten Anzahl von Unternehmen, die zahlungsfähig bleiben, ist die Anwendung der Push-Top Strategie teilweise geeigneter als die Push-Bottom Strategie. Nun stellt sich die Frage, ob die optimale Strategie für das jeweilige Optimierungsproblem auch dann gefunden werden kann, wenn die Unternehmen zu Beginn entsprechend einer willkürlichen Strategie durch die Regierung gefördert werden. Da die zugrunde liegende partielle Differentialgleichung für die Wertfunktion nichtlinear ist, können Standardmethoden für lineare partielle Differentialgleichungen nicht verwendet werden. Aus diesem Grund verwenden wir die Policy-Iterationsmethode, bei der in jedem Schritt eine verbesserte Strategie hergeleitet und die Lösung der dabei auftretenden linearen partiellen Differentialgleichung mit Hilfe von Differenzenquotienten und des Überrelaxationsverfahrens, auch SOR-Verfahren genannt, approximiert wird.This paper is concerned with the application and numerical implementation of the policy iteration method to a two-dimensional stochastic control model with two independent Brownian motions describing the behavior of two firms in a market, as presented in the article by McKean and Shepp [18]. In the article it was shown that the chosen strategy by which the companies are supported by the government in the form of tax breaks varies depending on the optimization criterion. It turns out that if the objective is to maximize the joint survival probability of both firms, the push-bottom strategy, i.e., the strategy that supports the weaker firm at the considered time, is the optimal strategy. If, on the other hand, the criterion is to maximize the expected number of firms that remain solvent, the application of the push-top strategy is partially more suitable than the push-bottom strategy. Now the question arises whether the optimal strategy for the respective optimization problem can be found even if the companies are subsidized by the government at the beginning according to an arbitrary strategy. Since the underlying partial differential equation for the value function is nonlinear, standard methods for linear partial differential equations cannot be used. For this reason, we use the policy iteration method, in which an improved policy is derived at each step and the solution of the thereby observed linear partial differential equation is approximated using difference quotients and the successive over-relaxation method.13

Energy Autonomous Wireless Sensing Node Working at 5 Lux from a 4 cm2 Solar Cell

Harvesting energy for IoT nodes in places that are permanently poorly lit is important, as many such places exist in buildings and other locations. The need for energy-autonomous devices working in such environments has so far received little attention. This work reports the design and test results of an energy-autonomous sensor node powered solely by solar cells. The system can cold-start and run in low light conditions (in this case 20 lux and below, using white LEDs as light sources). Four solar cells of 1 cm2 each are used, yielding a total active surface of 4 cm2. The system includes a capacitive sensor that acts as a touch detector, a crystal-accurate real-time clock (RTC), and a Cortex-M3-compatible microcontroller integrating a Bluetooth Low Energy radio (BLE) and the necessary stack for communication. A capacitor of 100 μF is used as energy storage. A low-power comparator monitors the level of the energy storage and powers up the system. The combination of the RTC and touch sensor enables the MCU load to be powered up periodically or using an asynchronous user touch activity. First tests have shown that the system can perform the basic work of cold-starting, sensing, and transmitting frames at +0 dBm, at illuminances as low as 5 lux. Harvesting starts earlier, meaning that the potential for full function below 5 lux is present. The system has also been tested with other light sources. The comparator is a test chip developed for energy harvesting. Other elements are off-the-shelf components. The use of commercially available devices, the reduced number of parts, and the absence of complex storage elements enable a small node to be built in the future, for use in constantly or intermittently poorly lit places

Identifying drivers of non-stationary climate-growth relationships of European beech

The future performance of the widely abundant European beech (Fagus sylvatica L.) across its ecological amplitude is uncertain. Although beech is considered drought-sensitive and thus negatively affected by drought events, scientific evidence indicating increasing drought vulnerability under climate change on a cross-regional scale remains elusive. While evaluating changes in climate sensitivity of secondary growth offers a promising avenue, studies from productive, closed-canopy forests suffer from knowledge gaps, especially regarding the natural variability of climate sensitivity and how it relates to radial growth as an indicator of tree vitality. Since beech is sensitive to drought, we in this study use a drought index as a climate variable to account for the combined effects of temperature and water availability and explore how the drought sensitivity of secondary growth varies temporally in dependence on growth variability, growth trends, and climatic water availability across the species’ ecological amplitude. Our results show that drought sensitivity is highly variable and non-stationary, though consis- tently higher at dry sites compared to moist sites. Increasing drought sensitivity can largely be explained by increasing climatic aridity, especially as it is exacerbated by climate change and trees’ rank progression within forest communities, as (co-)dominant trees are more sensitive to extra-canopy climatic conditions than trees embedded in understories. However, during the driest periods of the 20th century, growth showed clear signs of being decoupled from climate. This may indicate fundamental changes in system behavior and be early-warning signals of decreasing drought tolerance. The multiple significant interaction terms in our model elucidate the complexity of European beech’s drought sensitivity, which needs to be taken into consideration when assessing this species’ response to climate change