2,997 research outputs found

    Determining Resilience Gains from Anomaly Detection for Event Integrity in Wireless Sensor Networks

    Get PDF
    Measurements collected in a wireless sensor network (WSN) can be maliciously compromised through several attacks, but anomaly detection algorithms may provide resilience by detecting inconsistencies in the data. Anomaly detection can identify severe threats to WSN applications, provided that there is a sufficient amount of genuine information. This article presents a novel method to calculate an assurance measure for the network by estimating the maximum number of malicious measurements that can be tolerated. In previous work, the resilience of anomaly detection to malicious measurements has been tested only against arbitrary attacks, which are not necessarily sophisticated. The novel method presented here is based on an optimization algorithm, which maximizes the attack’s chance of staying undetected while causing damage to the application, thus seeking the worst-case scenario for the anomaly detection algorithm. The algorithm is tested on a wildfire monitoring WSN to estimate the benefits of anomaly detection on the system’s resilience. The algorithm also returns the measurements that the attacker needs to synthesize, which are studied to highlight the weak spots of anomaly detection. Finally, this article presents a novel methodology that takes in input the degree of resilience required and automatically designs the deployment that satisfies such a requirement

    NutriciĂłn del oso negro (Ursus americanus eremicus) en las serranĂ­as del Carmen, Coahuila

    Get PDF
    RESUMEN Se determinaron los componentes de la dieta del oso negro (Ursus americanus eremicus) en las serranías Maderas del Carmen, Coahuila. También se cuantificó la disponibilidad de los alimentos y su contenido de energía metabolizable. Se calcularon las necesidades energéticas de los osos y se estimó la capacidad de carga para esta especie. Se establecieron seis patrones estacionales de la dieta y se identificaron 28 componentes alimenticios, 92% de materia vegetal y 8% de materia animal. La capacidad de carga estimada para la etapa de máximos requerimientos energéticos de los osos es de 136 ha/ oso o 0.73 osos/km2. ABSTRACT The black bear (Ursus americanus eremicus) diet composition was determined in Maderas del Carmen Coahuila. The availability of the food was determined, as well as its metabolizable energy concentration. Black bear metabolizable energy requirements and carrying capacity were estimated. Six seasonal diet patterns were established. 28 food components were identified. 92% of the diet was vegetation and 8% animal matter. The estimated carrying capacity for Sierra del Carmen, Coahuila during the maximum bear energetic requirement phase is 136 ha/bear or 0.73 bears/km2

    Analyses of Genetic Diversity in the Endangered “Berrenda” Spanish Cattle Breeds Using Pedigree Data

    Get PDF
    Pedigree analyses of two endangered cattle breeds were performed in order to study the structure and the genetic variability in their populations. Pedigree data were analyzed from 12,057 individuals belonging to the “Berrenda en Negro” cattle breed (BN) and 20,389 individuals belonging to the “Berrenda en Colorado” cattle breed (BC) that were born between 1983 and 2020. BN and BC reference populations (RP) were set up by 2300 and 3988 animals, respectively. The generation interval in BN and BC reference populations was equal to 6.50 and 6.92 years, respectively. The pedigree completeness level was 82.76% in BN and 79.57% in BC. The inbreeding rates were 4.5% in BN and 3.4% in BC, respectively. The relationship among animals when they were born in different herds was 1.8% in BN and 5% in BC; these values increased to 8.5% and 7.7%, respectively when comparing animals that were born in the same herd. The effective number of founding herds was 23.9 in BN and 60.9 in BC. Number of ancestors needed to explain 50% of genes pool in the whole population was 50 and 101, in BN and in BC, respectively. The effective population size based on co-ancestries was 92.28 in BN and 169.92 in BC. The genetic variability has been maintained in both populations over time and the results of this study suggest that measures to promote the conservation of the genetic variability in these two breeds would go through for the exchange of breeding animals among farms and for monitoring the genetic contributions before implementing any selective action

    On the nature of the near-UV extended light in Seyfert galaxies

    Get PDF
    We study the nature of the extended near-UV emission in the inner kiloparsec of a sample of 15 Seyfert galaxies which have both near-UV (F330W) and narrow band [OIII] high resolution Hubble images. For the majority of the objects we find a very similar morphology in both bands. From the [OIII] images we construct synthetic images of the nebular continuum plus the emission line contribution expected through the F330W filter, which can be subtracted from the F330W images. We find that the emission of the ionised gas dominates the near-UV extended emission in half of the objects. A further broad band photometric study, in the bands F330W (U), F547M (V) and F160W (H), shows that the remaining emission is dominated by the underlying galactic bulge contribution. We also find a blue component whose nature is not clear in 4 out of 15 objects. This component may be attributed to scattered light from the AGN, to a young stellar population in unresolved star clusters, or to early-disrupted clusters. Star forming regions and/or bright off-nuclear star clusters are observed in 4/15 galaxies of the sample.Comment: 23 pages, 6 figures, 3 tables; accepted for publication in MNRA

    Emitters of NN-photon bundles

    Get PDF
    We propose a scheme based on the coherent excitation of a two-level system in a cavity to generate an ultrabright CW and focused source of quantum light that comes in groups (bundles) of NN photons, for an integer NN tunable with the frequency of the exciting laser. We define a new quantity, the \emph{purity} of NN-photon emission, to describe the percentage of photons emitted in bundles, thus bypassing the limitations of Glauber correlation functions. We focus on the case 1≤N≤31\le N\le3 and show that close to 100% of two-photon emission and 90% of three-photon emission is within reach of state of the art cavity QED samples. The statistics of the bundles emission shows that various regimes---from NN-photon lasing to NN-photon guns---can be realized. This is evidenced through generalized correlation functions that extend the standard definitions to the multi-photon level.Comment: Introduce the n-th order N-photon correlation functions. Reorganized to emphasize the N-photon emitter, now extended to the antibunching regime, rather than only coherent emission as previsoul

    Radiation damage evaluation on AlGaAs/GaAs solar cells

    Get PDF
    A computer model to evaluate radiation damage on AlGaAs-based solar cells is reported. The model is based on a piecewise approach that divides the cell structure in an adaptive number of slices. Inside a particular slice the semiconductor parameters are constant; consequently, it is easy to find an analytical solution of the semiconductor transport equations with suitable boundary conditions for the interfaces with the adjacent slices. The model provides all electrical parameters of the cells in the operating temperature range. Different structures, including graded band gaps and double heterofaces can be analyzed. Proton damage coefficients as well as proton damage ratios can be calculated for energies between 30 and 10/sup 4/ keV with only two adjustable parameters. Coirradiation experiments with different energy protons were simulated by improving the conventional method of degradation computering.Peer ReviewedPostprint (published version

    Preliminary Results from the 96 Spanish Bottom Trawl Survey in the NAFO Regulatory Area for Divisions 3NO

    Get PDF
    As the last year a stratified-random bottom trawl survey was performed in NAFO Regulatory Area (Divisions 3NO) during May: 7th to 24th. The survey, wich covered offshore areas of the Grand Bank, was conducted following the sames procedures and the same vessel and gear of the 1995 survey (Paz, et al, 1995). The area and strata to be covered by the survey were based on the stratification charts and tables in Bishop (1994)

    Preliminary Results from the 1997 Bottom Trawl Survey in the NAFO Regulatory Area for Divisions 3NO

    Get PDF
    As the previous years, a stratified-random bottom trawl survey was performed in NAFO Regulatory area (Division 3NO) during 26th April to 17th May. The survey, which covered offshore areas on the Grand Bank, was conducted following the same procedures and the same vessel and gear of the 1995 and 1996 surveys (Paz et al. 1995; 1996). The area and the strata to be covered by the survey were based on the stratification charts and tables in Bishop (1994)
    • …
    corecore