146 research outputs found

    Electric Power Grid Resilience to Cyber Adversaries: State of the Art

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    © 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. The smart electricity grids have been evolving to a more complex cyber-physical ecosystem of infrastructures with integrated communication networks, new carbon-free sources of powergeneratio n, advanced monitoring and control systems, and a myriad of emerging modern physical hardware technologies. With the unprecedented complexity and heterogeneity in dynamic smart grid networks comes additional vulnerability to emerging threats such as cyber attacks. Rapid development and deployment of advanced network monitoring and communication systems on one hand, and the growing interdependence of the electric power grids to a multitude of lifeline critical infrastructures on the other, calls for holistic defense strategies to safeguard the power grids against cyber adversaries. In order to improve the resilience of the power grid against adversarial attacks and cyber intrusions, advancements should be sought on detection techniques, protection plans, and mitigation practices in all electricity generation, transmission, and distribution sectors. This survey discusses such major directions and recent advancements from a lens of different detection techniques, equipment protection plans, and mitigation strategies to enhance the energy delivery infrastructure resilience and operational endurance against cyber attacks. This undertaking is essential since even modest improvements in resilience of the power grid against cyber threats could lead to sizeable monetary savings and an enriched overall social welfare

    Exploring wind direction and SO2 concentration by circular-linear density estimation

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    The study of environmental problems usually requires the description of variables with different nature and the assessment of relations between them. In this work, an algorithm for flexible estimation of the joint density for a circular-linear variable is proposed. The method is applied for exploring the relation between wind direction and SO2 concentration in a monitoring station close to a power plant located in Galicia (NW-Spain), in order to compare the effectiveness of precautionary measures for pollutants reduction in two different years.Comment: 17 pages, 7 figures, 2 table

    Self-Assembly of Nanoparticles onto the Surfaces of Polystyrene Spheres with a Tunable Composition and Loading

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    Functional colloidal materials were prepared by design through the self-assembly of nanoparticles (NPs) on the surfaces of polystyrene (PS) spheres with control over NP surface coverage, NP-to-NP spacing, and NP composition. The ability to control and fine tune the coating was extended to the first demonstration of the co-assembly of NPs of dissimilar composition onto the same PS sphere, forming a multi-component coating. A broad range of NP decorated PS (PS@NPs) spheres were prepared with uniform coatings attributed to electrostatic and hydrogen bonding interactions between stabilizing groups on the NPs and the functionalized surfaces of the PS spheres. This versatile two-step method provides more fine control than methods previously demonstrated in the literature. These decorated PS spheres are of interest for a number of applications, such as catalytic reactions where the PS spheres provide a support for the dispersion, stabilization, and recovery of NP catalysts. The catalytic properties of these PS@NPs spheres were assessed by studying the catalytic degradation of azo dyes, an environmental contaminant detrimental to eye health. The PS@NPs spheres were used in multiple, sequential catalytic reactions while largely retaining the NP coating

    Determing some important extracted materials, such as: Alginates of sodium & calcium and alginic acid in three species of brown seaweeds (Sargassum illicifolium, Cystoseira indica and Nizimuddinia zanardinii) in coastal area of Sistan and Baluochestan Province

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    This study was determined some important extracted materials, Such as : Alginates of sodium & calcium and alginic acid in three species of brown seaweeds (Sargassum illicifolium , Cystoseira indica and Nizimuddinia zanardinii) during in different season in 1387 in coastal erea of Sistan and Baluochestan Provience. At First seaweeds sample were colected from sea beach and transferd to lab, so washed in fresh water and dried in the sun. So were under Alkaloid extraction with sodium carbonate (5 Persent), that were obtined fluid after filteration. The sodium alginate fibers extracted from fluid were combined by Alcohol. The calacium alginate fibers were deposited by calacium chlorids (5%) and Alginic acid resulted with chloridric acid (1N). The extraction yield of sodium alginate, calacium alginate and alginic acid in different samples of seaweeds with following Explaination: The presentage we have got, can be said , the present average of sodium alginate at Sargassum in Spring season in three areas (Chabahar, Tang and Pasabandar ) Respectively: 28.4±2 , 28.9±2 , 27.2±1.9 present, the present average of sodium alginate at Cystoseira in Spring in three areas at above mentioned goes in this way: 19.7±1.4, 18.6±1.4, 19.2±1.3 present and the present average of sodium alginate at Nizimuddinia in Spring were 23.4±1.5, 23.8±1.5 , 20.6±1.5 in these three areas. The present average of calacium alginate at Sargassum in Spring season in three areas (Chabahar, Tang and Pasabandar ): 33.7±0.5, 33.7±0.8, 33.1±1 present, the present average of calacium alginate at Cystoseira in Spring in three areas at above mentioned goes in this way: 28.8±1.5, 27.4±1, 27.4±1.5 present and the present average of calacium alginate at Nizimuddinia in Spring were 35.9±2.8, 23.9±1.5 , 35.9±2.8 in these three areas. The present average of Alginic acid at Sargassum in Spring season in three areas (Chabahar, Tang and Pasabandar ): 19.2±1.6 , 25.6±1.7 , 18.4±1.1 present, the present average of Alginic acid at Cystoseira in Spring in three areas at above mentioned goes in this way: 16.8±1.2, 15.8±1.1, 16.4±1 present and the present average of Alginic acid at Nizimuddinia in Spring were 19.2±1.6, 19.6±1.7 , 18.4±1.5 in these three areas. The present average of sodium alginate at Sargassum in Summer season in three areas (Chabahar, Tang and Pasabandar ) Respectively: 20.8±1, 21±1, 27.8±1.9 present, the present average of sodium alginate at Cystoseira in Summer in three areas at above mentioned goes in this way: 21±1.1, 13.2±1, 14.1±0.7 present and the present average of sodium alginate at Nizimuddinia in Summer were 25.3±2.3, 16.7±2.1, 15.3±1.3 in these three areas. The present average of calacium alginate at Sargassum in Summer season in three areas (Chabahar, Tang and Pasabandar): 29.5±2.1 , 29.7±2 , 28.3±2.2 present, the present average of calacium alginate at Cystoseira in Summer in three areas at above mentioned goes in this way: 21±1.1, 20.2±0.9, 20±0.7 present and the present average of calacium alginate at Nizimuddinia in Summer were 25.3±2.3, 29.7±2 , 23.1±1.5 in these three areas. The present average of Alginic acid at Sargassum in Summer season in three areas (Chabahar, Tang and Pasabandar): 19.5±0.7 , 19.7±0.6 , 18.7±0.7 present, the present average of Alginic acid at Cystoseira in Summer in three areas at above mentioned goes in this way: 21±1.1, 11.5±1.4, 11.1±1.5 present and the present average of Alginic acid at Nizimuddinia in Summer were 14.8±1.3, 15.3±1.3 , 14.6±1 in these three areas. The present average of sodium alginate at Sargassum in Autumn season in three areas (Chabahar, Tang and Pasabandar) Respectively: 31.5±4.3, 31.6±4.8, 29.4±4.8 present, the present average of sodium alginate at Cystoseira in Autumn in three areas at above mentioned goes in this way: 23±2.7, 21.4±2.8, 21.4±2.7 present and the present average of sodium alginate at Nizimuddinia in Autumn were 25.8±2.2, 26.4±2.1 , 23.4±1.9 in these three areas. The present average of calacium alginate at Sargassum in Autumn season in three areas (Chabahar, Tang and Pasabandar): 43.3±1.6, 42.8±2.7, 41.7±2.9 present, the present average of calacium alginate at Cystoseira in Autumn in three areas at above mentioned goes in this way: 34.3±5.9, 32.4±5.5, 30.9±5.2 present and the present average of calacium alginate at Nizimuddinia in Autumn were 50±7.1, 50.2±7.5, 45.6±5.2 in these three areas. The present average of Alginic acid at Sargassum in Autumn season in three areas (Chabahar, Tang and Pasabandar): 28±3.8, 28±3.5, 26±3.9 present, the present average of Alginic acid at Cystoseira in Autumn in three areas at above mentioned goes in this way: 20.2±1.8, 19.2±2.1, 18.7±1.6 present and the present average of Alginic acid at Nizimuddinia in Autumn were 25.9±3, 26.1±2.9, 24.6±3.6 in these three areas. The present average of sodium alginate at Sargassum in Winter season in three areas (Chabahar, Tang and Pasabandar) Respectively: 35±1.6, 35.2±1.8 , 33.8±1.9 present, the present average of sodium alginate at Cystoseira in Winter in three areas at above mentioned goes in this way: 24.1±2, 22.9±1.2, 23.3±0.7 present and the present average of sodium alginate at Nizimuddinia in Winter were 28.2±1.3, 29.2±1.7, 26.2±1.8 in these three areas. The present average of calacium alginate at Sargassum in Winter season in three areas (Chabahar, Tang and Pasabandar): 45.6±1.9, 45±2, 44.6±2.5 present, the present average of calacium alginate at Cystoseira in Winter in three areas at above mentioned goes in this way: 38.2±2.8, 35.9±3.4, 35.6±3.5 present and the present average of calacium alginate at Nizimuddinia in Winter were 56.4±3.5, 56±3.5, 51.8±2.5 in these three areas. The present average of Alginic acid at Sargassum in winter season in three areas (Chabahar, Tang and Pasabandar): 31.8±1.2, 32.1±0.9, 30.9±1.2 present, the present average of Alginic acid at Cystoseira in Winter in three areas at above mentioned goes in this way: 21.1±1.2, 20.4±1.4, 19.3±1.4 present and the present average of Alginic acid at Nizimuddinia in Winter were 26.4±2.1, 27±2.2, 24.6±2.2 in these three areas. The more amount of calacium alginate in Autumn can be found at Nizimuddinia in Tang area , wite amount of 50.2 present and the lates amount of Alginic acid at Cystoseira can be found in Summer with 11.1 present. If the Alginic acid become more than 20 present, it can be economical, that it can be showed more than 20 present in Autumn and Winter. According to this results, One way ANOVA showed that average of Alginates were not similar and significant differences ( P<0.05 ) between species

    Chemical composition of nanoporous layer formed by electrochemical etching of p-type GaAs

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    Abstract : We have performed a detailed characterization study of electrochemically etched p-type GaAs in a hydrofluoric acid-based electrolyte. The samples were investigated and characterized through cathodoluminescence (CL), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). It was found that after electrochemical etching, the porous layer showed a major decrease in the CL intensity and a change in chemical composition and in the crystalline phase. Contrary to previous reports on p-GaAs porosification, which stated that the formed layer is composed of porous GaAs, we report evidence that the porous layer is in fact mainly constituted of porous As2O3. Finally, a qualitative model is proposed to explain the porous As2O3 layer formation on p-GaAs substrate

    Finite Element Analysis of Bone and Experimental Validation

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    This chapter describes the application of the finite element (FE) method to bone tissues. The aspects that differ the most between bone and other materials’ FE analysis are the type of elements used, constitutive models, and experimental validation. These aspects are looked at from a historical evolution stand point. Several types of elements can be used to simulate similar bone structures and within the same analysis many types of elements may be needed to realistically simulate an anatomical part. Special attention is made to constitutive models, including the use of density-elasticity relationships made possible through CT-scanned images. Other more complex models are also described that include viscoelasticity and anisotropy. The importance of experimental validation is discussed, describing several methods used by different authors in this challenging field. The use of cadaveric human bones is not always possible or desirable and other options are described, as the use of animal or artificial bones. Strain and strain rate measuring methods are also discussed, such as rosette strain gauges and optical devices.publishe

    SILKNOWViz: Spatio-temporal data ontology viewer

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    Interactive visualization of spatio-temporal data is a very active area that has experienced remarkable advances in the last decade. This is due to the emergence of fields of research such as big data and advances in hardware that allow better analysis of information. This article describes the methodology followed and the design of an open source tool, which in addition to interactively visualizing spatio-temporal data that are represented in an ontology, allows the definition of what to visualize and how to do it. The tool allows selecting, filtering and visualizing in a graphical way the entities of the ontology with spatiotemporal data, as well as the instances related to them. The graphical elements used to display the information are specified on the same ontology, extending the VISO graphic ontology, used for mapping concepts to graphic objects with RDFS/OWL Visualization Language (RVL). This extension contemplates the data visualization on rich real-time 3D environments, allowing different modes of visualization according to the level of detail of the scene, while also emphasizing the treatment of spatio-temporal data, very often used in cultural heritage models. This visualization tool involves simple visualization scenarios and high interaction environments that allow complex comparative analysis. It combines traditional solutions, like hypercube or time-animations with innovative data selection methods.Interactive visualization of spatio-temporal data is a very active area that has experienced remarkable advances in the last decade. This is due to the emergence of fields of research such as big data and advances in hardware that allow better analysis of information. This article describes the methodology followed and the design of an open source tool, which in addition to interactively visualizing spatio-temporal data that are represented in an ontology, allows the definition of what to visualize and how to do it. The tool allows selecting, filtering and visualizing in a graphical way the entities of the ontology with spatiotemporal data, as well as the instances related to them. The graphical elements used to display the information are specified on the same ontology, extending the VISO graphic ontology, used for mapping concepts to graphic objects with RDFS/OWL Visualization Language (RVL). This extension contemplates the data visualization on rich real-time 3D environments, allowing different modes of visualization according to the level of detail of the scene, while also emphasizing the treatment of spatio-temporal data, very often used in cultural heritage models. This visualization tool involves simple visualization scenarios and high interaction environments that allow complex comparative analysis. It combines traditional solutions, like hypercube or time-animations with innovative data selection methods

    Reduction of claustrophobia during magnetic resonance imaging: methods and design of the "CLAUSTRO" randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Magnetic resonance (MR) imaging has been described as the most important medical innovation in the last 25 years. Over 80 million MR procedures are now performed each year and on average 2.3% (95% confidence interval: 2.0 to 2.5%) of all patients scheduled for MR imaging suffer from claustrophobia. Thus, prevention of MR imaging by claustrophobia is a common problem and approximately 2,000,000 MR procedures worldwide cannot be completed due to this situation. Patients with claustrophobic anxiety are more likely to be frightened and experience a feeling of confinement or being closed in during MR imaging. In these patients, conscious sedation and additional sequences (after sedation) may be necessary to complete the examinations. Further improvements in MR design appear to be essential to alleviate this situation and broaden the applicability of MR imaging. A more open scanner configuration might help reduce claustrophobic reactions while maintaining image quality and diagnostic accuracy.</p> <p>Methods/Design</p> <p>We propose to analyze the rate of claustrophobic reactions, clinical utility, image quality, patient acceptance, and cost-effectiveness of an open MR scanner in a randomized comparison with a recently designed short-bore but closed scanner with 97% noise reduction. The primary aim of this study is thus to determine whether an open MR scanner can reduce claustrophobic reactions, thereby enabling more examinations of claustrophobic patients without incurring the safety issues associated with conscious sedation. In this manuscript we detail the methods and design of the prospective "CLAUSTRO" trial.</p> <p>Discussion</p> <p>This randomized controlled trial will be the first direct comparison of open vertical and closed short-bore MR systems in regards to claustrophobia and image quality as well as diagnostic utility.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00715806">NCT00715806</a></p
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