19 research outputs found

    On Security Log Management Systems

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    A log management system (LMS) is a system for creating, receiving, processing, releasing, and transferring of security log data. Its main objectives include detecting and preventing unauthorised access and abuse, and meeting regulatory requirements. One of its main components is the classification of events to make decisions related to archiving and to invoking responses to certain events. Most current approaches to LMS design are system dependent and involve specific hardware (e.g., firewalls, servers) and commercial software systems. This paper presents a theoretical framework for LMS in terms of a flow-based conceptual model with emphasis on security-related events. The framework includes four separate flow systems: active system, log system, alarm system, and response system. All systems are composed of five inclusive stages: receiving, processing, creating, releasing, and transferring. The experimental part of the paper concentrates on log analysis in the processing stage in the log system. We select actual log entries and classify them according to these five stages

    Evaluation of microleakage and strength adhesive of composite resin restorations with total etch adhesive system in primary and permanent teeth

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    Indexación: Web of Science; Scielo.El presente estudio evaluó el grado de sellado marginal y resistencia adhesiva de restauraciones de resinas compuestas confeccionadas con un sistema adhesivo de grabado y lavado en dentición primaria y definitiva. Para realizar ambos test se utilizaron 20 piezas primarias y 20 piezas definitivas. En resistencia al cizallamiento, los dientes fueron seccionados longitudinalmente y se les adhirió un cilindro de resina compuesta, utilizando la técnica adhesiva de grabado y lavado para ambas denticiones. Posteriormente, fueron testeados en una máquina de ensayos universales Tinius Olsen, aplicando una fuerza de cizallamiento de 200 kg y a una velocidad de cabezal de 0,2 cm/min. Para el test de sellado marginal, se les realizó una preparación cavitaria clase V, por vestibular/palatino estandarizada. Luego se les confeccionaron restauraciones de resina compuesta con la técnica de grabado y lavado, y se sometieron al termociclado con azul de metileno al 2%; después fueron cortados y observados al microscopio óptico estereoscópico con aumento de lupa, para medir el porcentaje de microfiltración obtenido. El valor promedio de la resistencia adhesiva al cizallamiento para dentición primaria fue de 8,49 Mpa, y de 9,52 Mpa para dentición definitiva, no encontrándose diferencias estadísticamente significativas entre los grupos en estudio. En la investigación sobre el grado de sellado marginal se evaluó el porcentaje de microfiltración y tampoco se encontraron diferencias estadísticamente significativas, lo que señalaría que ambos tejidos son igualmente susceptibles de ser tratados adhesivamente mediante la técnica de hibridación.Abstract The present study evaluated the degree of marginal seal and adhesive resistance of composite resin restorations prepared with an etch and rinse adhesive system in primary and definitive dentition. To perform both tests, 20 primary pieces and 20 permanent pieces were used. In the shear strength resistance, the teeth were sectioned longitudinally and were adhered to composite resin cylinder, using the etch and rinse technique for both dentitions. They were then tested on a Tinius Olsen universal testing machine, applying a shear force of 200 kg and a head speed of 0.2 cm/min. For the margin seal test, a class V cavity preparation of standardised vestibular/palatine was made. The composite resin restorations were made with the etch and rinse technique and were subjected to thermocycling with 2% methylene blue. Later, they were cut and observed using a stereoscopic optical microscope with loop magnification to measure the percentage of microfiltration obtained. The mean value of the adhesive resistance to shearing for primary dentition was 8.49 Mpa, and 9.52 Mpa for permanent teeth, with no statistically significant differences being found between the groups studied. In the test on the degree of margin seal the percentage microfiltration was measured, with no statistically significant differences being found either. The results showed that both tissues are equally susceptible to being treated adhesively using the hybrid techniquehttp://ref.scielo.org/53nph

    The International Soil Moisture Network:Serving Earth system science for over a decade

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    In 2009, the International Soil Moisture Network (ISMN) was initiated as a community effort, funded by the European Space Agency, to serve as a centralised data hosting facility for globally available in situ soil moisture measurements (Dorigo et al., 2011b, a). The ISMN brings together in situ soil moisture measurements collected and freely shared by a multitude of organisations, harmonises them in terms of units and sampling rates, applies advanced quality control, and stores them in a database. Users can freely retrieve the data from this database through an online web portal (https://ismn.earth/en/, last access: 28 October 2021). Meanwhile, the ISMN has evolved into the primary in situ soil moisture reference database worldwide, as evidenced by more than 3000 active users and over 1000 scientific publications referencing the data sets provided by the network. As of July 2021, the ISMN now contains the data of 71 networks and 2842 stations located all over the globe, with a time period spanning from 1952 to the present. The number of networks and stations covered by the ISMN is still growing, and approximately 70 % of the data sets contained in the database continue to be updated on a regular or irregular basis. The main scope of this paper is to inform readers about the evolution of the ISMN over the past decade, including a description of network and data set updates and quality control procedures. A comprehensive review of the existing literature making use of ISMN data is also provided in order to identify current limitations in functionality and data usage and to shape priorities for the next decade of operations of this unique community-based data repository

    A techno-economic assessment of offshore wind energy in Chile

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    Offshore wind energy potential and its technical and economic feasibility were determined in Chile. Wind speed data from ERA-Interim reanalysis 10 m above the sea surface between 1979 and 2014 was used. The capacity factor and performance of the V164-8.0 MW wind generator was also determined. Using this information along with data from other studies, the following economic indicators were calculated: Levelized Cost Of Energy (LCOE), Net Present Value (NPV), Internal Rate of Return (IRR) and Pay-Back (PB). The results show that the area between 45 and 56 degrees S has the highest values in terms of both power density (similar to 3190 W/m(2)) and capacity factor (similar to 70%), as well as the lowest LCOE values (72-100 USD /MWh).Theareabetween30and32degreesSwasestimatedtobethemostsuitableareaforimplementinganoffshorewindprojectbecauseofitswindpowerdensity(between700W/m2and900W/m2),capacityfactorsbetween40/MWh). The area between 30 and 32 degrees S was estimated to be the most suitable area for implementing an offshore wind project because of its wind power density (between 700 W/m2 and 900 W/m2), capacity factors between 40% and 60%, LCOE between 100 and 114 USD/MWh. This work shows how important studying Chile's offshore wind power is for to be used and for removing barriers to current knowledge about this renewable energy and the benefits it would bring to Chile's power array."Programa de Estimulo a la Excelencia Institucional (PEEI)"-University of Chile 27101

    Decrease in snow cover over the Aysen river catchment in Patagonia, Chile

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    The evidence for global warming can be seen in various forms, such as glacier shrinkage, sea ice retreat, sea level rise and air temperature increases. The magnitude of these changes tends to be critical over pristine and extreme biomes. Chilean Patagonia is one of the most pristine and uninhabited regions in the world, home to some of the most important freshwater reservoirs as well as to evergreen forest, lakes and fiords. Furthermore, this region presents a sparse and weak network of ground stations which must be complemented with satellite information to determine trends on biophysical parameters. The main objective of this work is to present the first assessment on snow cover over the Aysen basin in Patagonia-Chile by using Moderate Resolution Imaging Spectroradiometer (MODIS) data from the period 2000-2016. The MOD10A2 product was processed at 500 x 500 m spatial resolution. The time-series analysis consisted in the application of non-parametric tests such as the Mann-Kendall test and Sen's slope for annual and seasonal mean of snow covered area (SCA). Data from ground meteorological network and river discharges were also included in this work to show the trends in air temperature, precipitation and stream flow during the last decades. Results indicate that snow cover shows a decreasing non-significant trend in annual mean SCA with a -20.01 km(2)year(-1) slope, and neither seasonal mean shows statistical significance. The comparison with in situ data shows a seasonal decrease in stream flows and precipitation during summer. The hydrological year 2016 was the year with the most negative standardized joint anomalies in the period. However, the lack of in situ snow-monitoring stations in addition to the persistence of cloud cover over the basin can impact trends, creating some uncertainties in the data. Finally, this work provides an initial analysis of the possible impacts of global warming as seen by snow cover in Chilean Patagonia

    Trends in column integrated water vapour over Europe from 1973 to 2003

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    The spatial and temporal variations of atmospheric precipitable water (PW) content anomalies were analysed over Europe from 1973 to 2003 using daily data (0000 and 1200 UTC) from National Center of Environmental Prediction and National Center of Atmospheric Research Reanalysis project (NCEP-1) and in situ radiosonde data. Mann-Kendall trend tests were applied to long-term PW time series. Technology changes influence PW radiosonde trends, although these are in agreement with NCEP-1 trends. Over the south of the Iberian Peninsula, trends are negative and statistically significant (<-0.04 mm year-1; p < 0.05) and positive over the Central European Mountains (The Alpes) and the North Atlantic Ocean (>0.04 mm year-1; p < 0.05). Seasonal trends revealed negative and significant trends over the Iberian Peninsula for all seasons (<-0.03 mm year-1; p < 0.05

    Atacama Field Campaign: laboratory and in-situ measurements for remote sensing applications

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    This work presents the preliminary results of the first field calibration campaign performed in the Atacama Desert, Chile, between the 18 and 22 August 2014, called the Atacama Field Campaign (ATAFIC 2014). In situ measurements were performed in order to spectrally characterize the surface reflectance spectra between 0.3 and 2.5 µm, radiometric temperature (8.0–14.0 µm) and atmospheric measurements. A soil sample was collected and analyzed using Fourier Transform Infrared Spectroscopy and X-Ray Diffraction techniques to characterize the surface reflectance spectra and mineralogical composition, respectively. ASTER land surface emissivity in addition to GOES, MODIS and Landsat-8 land surface temperature (LST) were also used. Results showed that the spectral features of the Atacama soil and the characteristics of this geographical zone, which is featured as the most hyper-arid and cloudless place in the world, make this area a potential target for surface reflectance characterization. Day and night LST comparison between field and remote sensing data are lower than 2 K and the Root Mean Square Error for land surface emissivity is close to 2%. This work opens the possibilities to consider the Atacama Desert as a reference target for calibration and validation activities for earth observation missions’ purposes

    Global Atmospheric Profiles from Reanalysis Information (GAPRI): a new database for earth surface temperature retrieval

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    Artículo de publicación ISISin acceso a texto completoThis paper presents the Global Atmospheric Profiles derived from Reanalysis Information (GAPRI) database, which was designed for earth surface temperature retrieval. GAPRI is a comprehensive compilation of selected atmospheric vertical profiles at global scale which can be used for radiative transfer simulation in order to obtain generalized algorithms to estimate land surface temperature (LST). GAPRI includes information on geopotential height, atmospheric pressure, air temperature, and relative humidity derived from the European Centre for Medium-Range Weather Forecasts Re-Analysis data from year 2011. The atmospheric profiles are structured for 29 vertical levels and extracted from a global spatial grid of about 0.75 degrees x 0.75 degrees latitude-longitude with a temporal resolution of 6hours. The selection method is based in the extraction of clear sky profiles over different atmospheric weather conditions such as tropical, mid-latitude summer, subarctic, and arctic, while also considering sea and land areas and day- and night-time conditions. The GAPRI database was validated by comparing land and sea surface temperature values derived from it to those obtained using other existing atmospheric profile databases and in situ measurements. Moreover, GAPRI was also compared to previous radiosonde atmospheric profiles using simulated split-window algorithms. Results show good agreement between GAPRI and previous atmospheric databases, thus demonstrating the potential of GAPRI for studies related to forward simulations in the thermal infrared range. GAPRI is a freely available database that can be modified according to the user's needs and local atmospheric conditionsproject Fondecyt-Initial [CONICYT] 11130359 Ministerio de Economia y Competitividad of Spain [CEOS-Spain] AYA2011-29334-C02-0

    Feed materials used in the preparation of food in pork production and its potential for dioxin contamination in the meat

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    This study assessed the contribution of various feed ingredients used in swine feeding as a source of dioxins, furans and dioxin like polychlorinated biphenyls (DL-PCBs) contamination in pork, considering the dietary changes during breeding, raising and fattening. Raw materials or feed ingredients were separated into different categories, developing a dataset with EROD/H4IIE bioassay results (determination of 7-Ethoxyresorufin O-Deethylase activity in H4IIE hepatoma cell line). Two types of diets were established that considered the varying percentages of ingredients necessary during the productive cycle of these animals. These two diets were based on those of common use in Chile. A descriptive analysis of the information contained in the dataset was performed, characterising the observations behaviour. A transfer model in which the body burden of dioxin increases proportionally to the consumption of contaminated food was proposed. The highest average contaminant concentration, expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalent toxics derived from the EROD/H4IIE bioassay (TCDD-EQ/g) was found in ingredients of mineral origin (16.21 pg TCDD-EQ/g), followed by those of fatty acid mixtures (2.03 pg TCDD-EQ/g), while the lowest average concentrations were found in dietary premixes (0.29 pg TCDD-EQ/g) and vegetable oils (0.35 pg TCDD-EQ/g). With regard to the fransfer model, the evaluation of the contribution of the different feed ingredients to the total amount of diet contamination showed that the vegetable components had the highest value, due to the high proportion of them in feed. The second highest contributor was the raw material of mineral source
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