Network traffic analysis is an important cybersecurity task, which helps to classify anomalous, potentially dangerous connections. In many cases, it is critical not only to detect individual ...malicious connections, but to detect which node in a network has generated malicious traffic so that appropriate actions can be taken to reduce the threat and increase the system’s cybersecurity. Instead of analysing connections only, node behavioural analysis can be performed by exploiting the graph information encoded in a connection network. Network traffic, however, is temporal data and extracting graph information without a fixed time scope may only unveil macro-dynamics that are less related to cybersecurity threats. To address these issues, a threefold approach is proposed here: firstly, temporal dissection for extracting graph-based information is applied. As the resulting graphs are typically affected by class imbalance (i.e. malicious nodes are under-represented), two novel graph data-level preprocessing techniques - R-hybrid and SM-hybrid - are introduced, which focus on exploiting the most relevant graph substructures. Finally, a Neural Network (NN) and two Graph Convolutional Network (GCN) approaches are compared when performing node behaviour classification. Furthermore, we compare the node classification performance of these supervised models with traditional unsupervised anomaly detection techniques. Results show that temporal dissection parameters affected classification performance, while the data-level preprocessing strategies reduced class imbalance and led to improved supervised node behaviour classification, outperforming anomaly detection models. In particular, Neural Network (NN) outperformed Graph Convolutional Network (GCN) approaches for two attack families and was less affected by class imbalance, yet one GCN performed best overall. The presented study successfully applies a temporal graph-based approach for malicious actor detection in network traffic data.
Nowadays, it is highly important to keep road maps up-to-date since a great deal of services rely on them. However, to date, these labours have demanded a great deal of human attention due to their ...complexity. In the last decade, promising attempts have been carried out to fully-automatize the extraction of road networks from remote sensing imagery. Nevertheless, the vast majority of methods rely on aerial imagery (< 1 m), whose costs are not yet affordable for maintaining up-to-date maps. This work proves that it is also possible to accurately detect roads using high resolution satellite imagery (10 m). Accordingly, we have relied on Sentinel-2 imagery considering its freely availability and the higher revisit times compared to aerial imagery. It must be taken into account that the lack of spatial resolution of this sensor drastically increases the difficulty of the road detection task, since the feasibility to detect a road depends on its width, which can reach sub-pixel size in Sentinel-2 imagery. For that purpose, a new deep learning architecture which combines semantic segmentation and super-resolution techniques is proposed. As a result, fine-grained road maps at 2.5 m are generated from Sentinel-2 imagery.
SUPER-RESOLUTION FOR SENTINEL-2 IMAGES
The international archives of the photogrammetry, remote sensing and spatial information sciences/International archives of the photogrammetry, remote sensing and spatial information sciences,
09/2019
Conference Proceeding
Pharmaceutical agents, like diclofenac and acetaminophen, are sold without prescription leading to excessive use. These agents may reach water bodies through various routes and attain significant ...concentrations, posing a risk to hydrobiont health. Diverse studies have shown that during the biotransformation of these compounds, reactive metabolites and reactive oxygen species are produced which induce oxidative stress and damage to diverse biomolecules. However, toxicity studies that assess the effects of a mixture of contaminants are scarce, being very important as this is how they are actually in the environment. The present study aimed to evaluate the oxidative stress induced by mixture of diclofenac and acetaminophen on Cyprinus carpio and compare with the effect produced by these pharmaceuticals in isolation. A 96-h sublethal toxicity assay of the tested pharmaceuticals (isolated and in mixture) was performed and the following biomarkers were evaluated: lipid peroxidation, protein carbonyl content, and activity of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. The pharmaceuticals evaluated induce oxidative stress on C. carpio in isolated form and as a mixture, but the level of damage being dependent on the organ evaluated as well as the type of toxicant and form of exposure (in isolation or as a mixture).
The Madín Dam is a reservoir located in the municipalities of Naucalpan and Atizapán, in the metropolitan area adjacent to Mexico City. The reservoir supplies drinking water to nearby communities and ...provides an area for various recreational activities, including kayaking, sailing and carp fishing. Over time, the number of specimens of common carp has notably diminished in the reservoir, which receives direct domestic drainage from two towns as well as numerous neighborhoods along the Tlalnepantla River. Diverse studies have demonstrated that the pollutants in the water of the reservoir produce oxidative stress, genotoxicity and cytotoxicity in juvenile Cyprinus carpio, possibly explaining the reduction in the population of this species; however, it is necessary to assess whether these effects may also be occurring directly in the embryos. Hence, surface water samples were taken at five sites and pharmaceutical drugs, personal care products (especially sunscreens), organophosphate and organochlorine pesticides, and other persistent organic pollutants (e.g., polychlorinated biphenyls and polycyclic aromatic hydrocarbons) were identified. Embryos of C. carpio were exposed to the water samples to evaluate embryolethality, modifications in embryonic development, lipoperoxidation, the quantity of hydroperoxide and oxidized proteins, and antioxidant enzyme activity (superoxide dismutase, catalase and glutathione peroxidase). It was found that the polluted water of the Madín Dam gave rise to embryolethality, embryotoxicity, congenital abnormalities, and oxidative stress on the common carp embryos.
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•The water of the Madin dam contains hydrocarbons of various types.•These hydrocarbons in combination with other contaminants from the site produce embryotoxicity in the common carp.•Cyprinus carpio is at risk in the Madín reservoir.
The water of the Madín dam contains a complex mixture of pollutants, including hydrocarbons, which produce oxidative stress and embryotoxicity on Cyprinus carpio.
Content-aware, edge-preserving smoothing techniques have gained visibility in recent years. However, they have had a rather limited impact on the edge detection literature compared to content-unaware ...(linear) techniques, often based on Gaussian filters. In this work, we focus on Anisotropic Diffusion, covering its initial definition by Perona and Malik and subsequent extensions. A visual case study is used to illustrate their features. We perform a quantitative evaluation of the performance of the Canny method for edge detection when substituting linear Gaussian smoothing filters by Anisotropic Diffusion.
•Reviewing the main trends in Anisotropic Diffusion.•Identifying the practical scenarios on which Anisotropic Diffusion fails.•Quantifying the improvement of edge detection when Anisitropic Diffusion is applied.
Colonization of sorghum and wheat after seed inoculation with Gluconacetobacter diazotrophicus strains PAL 5 and UAP 5541/pRGS561 (containing the marker gene gusA) was studied by colony counting and ...microscopic observation of plant tissues. Inoculum levels as low as 10² CFU per seed were enough for root colonization and further spreading in aerial tissues. Rhizoplane colonization was around 7 log CFU g⁻¹ (fresh weight). G. diazotrophicus was found inside sorghum and wheat roots with populations higher than 5 log CFU g⁻¹ (fresh weight). Stem colonization remained stable for 30 days post inoculation with endophyte concentrations from 4 to 5 log CFU g⁻¹ (fresh weight) (in both plants). Population in leaves decreased continuously being undetectable after 17 days post inoculation.
Madín Reservoir provides a substantial amount of drinking water to two municipalities close to Mexico City metropolitan area. However, it receives untreated wastewater discharges from domestic ...sources in the towns of Nuevo Madín and others, as well as diverse pollutants which are hauled by the Río Tlalnepantla from its upper reaches, so that the xenobiotics in the reservoir are highly diverse in terms of type and quantity. Previous studies showed that MR is contaminated with xenobiotics such as Al, Hg and Fe, as well as NSAIDs, at concentrations exceeding the limits established for aquatic life protection. These pollutants have been shown to induce oxidative stress on Cyprinus carpio and may therefore also damage the genetic material of exposed organisms, eliciting cytotoxicity as well. The present study aimed to determine the genotoxicity and cytotoxicity induced on blood, liver and gill of C. carpio by the pollutants present in MR water. Specimens were exposed to water from five sampling sites and the following biomarkers were evaluated: DNA damage by comet assay, frequency of micronuclei, apoptosis by TUNEL assay and caspase-3 activity. Significant increases relative to the control group (P < 0.05) were found with all biomarkers in all tissues evaluated, with the level of damage differing between sampling sites. In conclusion, pollutants present in MR water are genotoxic and cytotoxic to C. carpio, and this sentinel species, coupled with the biomarkers evaluated herein, is a reliable tool for assessing the health risk to wildlife posed by exposure to pollutants in freshwater bodies.
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•The Madín Dam is polluted by cytotoxic and genotoxic compounds, like heavy metals and pharmaceutical products.•Cyprinus carpio is at risk in the Madín reservoir.•Cytotoxicity and genotoxicity tests are a good tool to assess the risk of pollutants in water bodies.
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