Theoretical and experimental evaluation of the electromagneticradiation from apertures in shielded enclosure

The problem of the radiated emission from apertures in metallic enclosures has been theoretically and experimentally investigated. In particular, the tangential electric field in the aperture has been evaluated by two methods: the first is helpful during the design stage and the second during the prototype development stage of electronic equipment shielded by a metallic box. The first method is a rigorous approach and uses the equivalence principle that leads to an integral equation then solved by the method of moments. The second is an approximate technique. This technique is based on simple, cheap, and quick measurements of the normal components of the magnetic field across the aperture. Numerical simulation in good agreement with experimental results is shown     

An Extensive Evaluation of Decision Tree–Based Hierarchical Multilabel Classification Methods and Performance Measures

Hierarchical multilabel classification is a complex classification problem where an instance can be assigned to more than one class simultaneously, and these classes are hierarchically organized with superclasses and subclasses, that is, an instance can be classified as belonging to more than one path in the hierarchical structure. This article experimentally analyses the behavior of different decision tree–based hierarchical multilabel classification methods based on the local and global classification approaches. The approaches are compared using distinct hierarchy‐based and distance‐based evaluation measures, when they are applied to a variation of real multilabel and hierarchical datasets' characteristics. Also, the different evaluation measures investigated are compared according to their degrees of consistency, discriminancy, and indifferency. As a result of the experimental analysis, we recommend the use of the global classification approach and suggest the use of the Hierarchical Precision and Hierarchical Recall evaluation measures.     

Hierarchical multi-label classification using local neural networks

Hierarchical multi-label classification is a complex classification task where the classes involved in the problem are hierarchically structured and each example may simultaneously belong to more than one class in each hierarchical level. In this paper, we extend our previous works, where we investigated a new local-based classification method that incrementally trains a multi-layer perceptron for each level of the classification hierarchy. Predictions made by a neural network in a given level are used as inputs to the neural network responsible for the prediction in the next level. We compare the proposed method with one state-of-the-art decision-tree induction method and two decision-tree induction methods, using several hierarchical multi-label classification datasets. We perform a thorough experimental analysis, showing that our method obtains competitive results to a robust global method regarding both precision and recall evaluation measures.     

GBA Mutations Influence the Release and Pathological Effects of Small Extracellular Vesicles from Fibroblasts of Patients with Parkinson’s Disease

Heterozygous mutations in the GBA gene, encoding the lysosomal enzyme glucocerebrosidase (GCase), are the strongest known genetic risk factor for Parkinson’s disease (PD). The molecular mechanisms underlying the increased PD risk and the variable phenotypes observed in carriers of different GBA mutations are not yet fully elucidated. Extracellular vesicles (EVs) have gained increasing importance in neurodegenerative diseases since they can vehiculate pathological molecules potentially promoting disease propagation. Accumulating evidence showed that perturbations of the endosomal–lysosomal pathway can affect EV release and composition. Here, we investigate the impact of GCase deficiency on EV release and their effect in recipient cells. EVs were purified by ultracentrifugation from the supernatant of fibroblast cell lines derived from PD patients with or without GBA mutations and quantified by nanoparticle tracking analysis. SH-SY5Y cells over-expressing alpha-synuclein (α-syn) were used to assess the ability of patient-derived small EVs to affect α-syn expression. We observed that defective GCase activity promotes the release of EVs, independently of mutation severity. Moreover, small EVs released from PD fibroblasts carrying severe mutations increased the intra-cellular levels of phosphorylated α-syn. In summary, our work shows that the dysregulation of small EV trafficking and alpha-synuclein mishandling may play a role in GBA-associated PD.     

Comparison EUROMET.EM-K8 of DC voltage ratio: results

A regional key comparison of dc voltage ratio has been carried out in Europe. The method to evaluate the comparison reference value, the resulting degrees of equivalence for the voltage ratios 1000 V/10 V and 100 V/10 V and the link to the corresponding worldwide key comparison CCEM-K8 are reported.     

Wide-band characterization of current probes

The use of current probes for the injection of wide-band disturbance in electromagnetic compatibility applications requires their accurate characterization up to few gigahertz. While the representation of the current probe with a simple transformer is acceptable at low frequencies, the spectral content of fast signals requires models which are accurate even at gigahertz frequencies. This can be accomplished directly by measurements in the frequency domain (FD), making use of a S-matrix representation of the probe, or in the time domain (TD), recovering the transfer functions from the impulse responses measurement. Both techniques suffer limitations due to numerical and experimental problems; in particular, the FD approach leads to the solution of an inverse problem, with numerical instabilities in the high-frequency range, whereas the TD approach is not so accurate in the low-frequency range of the sought transfer function. The paper combines the two techniques to overcome these difficulties and achieve a better accuracy across the overall bandwidth. The characterization of a commercially available current probe allows comparison of numerical results with experimental measurements.     

Vehicle and Guard Rail Detection Using Radar and Vision Data Fusion

This paper describes a vehicle detection system fusing radar and vision data. Radar data are used to locate areas of interest on images. Vehicle search in these areas is mainly based on vertical symmetry. All the vehicles found in different image areas are mixed together, and a series of filters is applied in order to delete false detections. In order to speed up and improve system performance, guard rail detection and a method to manage overlapping areas are also included. Both methods are explained and justified in this paper. The current algorithm analyzes images on a frame-by-frame basis without any temporal correlation. Two different statistics, namely: 1) frame based and 2) event based, are computed to evaluate vehicle detection efficiency, while guard rail detection efficiency is computed in terms of time savings and correct detection rates. Results and problems are discussed, and directions for future enhancements are provided     

Rates and controls of nitrous oxide and nitric oxide emissions following conversion of forest to pasture in Rondônia

Tropical soils are important sources of nitrous oxide (N₂O) and nitric oxide (NO) emissions from the Earths terrestrial ecosystems. Clearing of tropical rainforest for pasture has the potential to alter N₂O and NO emissions from soils by altering moisture, nitrogen supply or other factors that control N oxide production. In this review we report annual rates of N₂O and NO emissions from forest and pastures of different ages in the western Brazilian Amazon state of Rondônia and examine how forest clearing alters the major controls of N oxide production. Forests had annual N₂O emissions of 1.7 to 4.3 kg N ha^-1 y^-1 and annual NO emissions of 1.4 kg N ha^-1 y^-1. Young pastures of 1–3 years old had higher N₂O emissions than the original forest (3.1–5.1 kg N ha^-1 y^-1) but older pastures of 6 years or more had lower emissions (0.1 to 0.4 kg N ha^-1 y^-1). Both soil moisture and indices of soil N cycling were relatively poor predictors of N₂O, NO and combined N₂O + NO emissions. In forest, high N₂O emissions occurred at soil moistures above 30 water-filled pore space, while NO emissions occurred at all measured soil moistures (18–43). In pastures, low N availability led to low N₂O and NO emissions across the entire range of soil moistures. Based on these patterns and results of field fertilization experiments, we concluded that: (1) nitrification was the source of NO from forest soils, (2) denitrification was not a major source of N₂O production from forest soils or was not limited by NO- supply, (3) denitrification was a major source of N₂O production from pasture soils but only when NO₃^- was available, and (4) nitrification was not a major source of 3 NO production in pasture soils. Pulse wettings after prolonged dry periods increased N₂O and NO₃^- emissions for only short periods and not enough to appreciably affect annual emission rates. We project that Basin-wide, the effect of clearing for pasture in the future will be a small reduction in total N₂O emissions if the extensive pastures of the Amazon continue to be managed in a way similar to current practices. In the future, both N₂Oand NO fluxes could increase if uses of pastures change to include greater use of N fertilizers or N-fixing crops. Predicting the consequences of these changes for N oxide production will require an understanding of how the processes of nitrification and denitrification interact with soil type and regional moisture regimes to control N₂O and NO production from these new anthropogenic N sources.     

Electrical fast-transient test: conducted and radiated disturbancedetermination by a complete source modeling

Tests against electrical fast transient/burst (EFT) represent a serious threat for modern high-speed electronics: besides the conducted injection of high amplitude pulse, a strong radiated field is produced during this test. The prediction of the effects of this test during the equipment early design stage requires the equivalent circuit of the generator: the output waveform into a resistive 50-Ω load is not sufficient to recover the complete circuit, including inductive component and parasitic elements. These are essential to predict the disturbance produced in arbitrary loads, as the equipment under test can be viewed. This paper describes how to characterize the EFT generator by means of the measurement of the output voltage and current produced in presence of known loads; moreover, a procedure to calculate the current on the equipment power cord is shown, based on the use of a circuit simulator (PSPICE). Finally, the disturbance produced on different loads and the radiated field during the test are calculated and experimentally validated