1,746 research outputs found

    Diplomado de Profundización CISCO Prueba de Habilidades Prácticas CCNP

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    Con la realización del diplomado CCNP, se desarrolla un escenario de habilidades prácticas, el cual es elaborado como opción de grado para adquirir el título de Ingeniería de Telecomunicaciones y de Electrónica, donde es utilizado el simulador de red GNS3 con dispositivos CISCO. La configuración de protocolos aplicados a los sistemas de conmutación en capa 2 y con la configuración realizada a los dispositivos de enrutamiento de capa 3 del modelo OSI, se logra la configuración de una red, que le permite a la empresa tener mayor seguridad y optimización en el uso de los recursos tecnológicos.With the completion of the CCNP diploma, a scenario of practical skills is developed, which is developed as a degree option to acquire the title of Telecommunications and Electronics Engineering, where the GNS3 network simulator with CISCO devices is used. The configuration of protocols applied to the switching systems in layer 2 and with the configuration made to the routing devices of layer 3 of the OSI model, the configuration of a network is achieved, which allows the company to have greater security and optimization in the use of technological resources

    Performance characterization of a multiplexed space-to-ground optical network

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    Advances in phased array systems for multi-beam free space optical communications are a key enabler for a new space-to-ground network architecture, namely a multiplexed optical architecture. The fundamental idea of a multiplexed space-to-ground optical network is the utilization of a multi-beam optical payload that allows each spacecraft to establish links with multiple ground stations within its line of sight. Information is then downlinked in parallel, from the satellite to the ground, through the subset of links not disrupted by clouds. In this paper we evaluate the performance of a multiplexed optical space-to-ground architecture from a systems perspective, with particular emphasis on the effect of cloud correlation in the network throughput. In particular, we first derive the expected data volume returned in a multiplexed architecture as a function of the optical network availability and the system total capacity. Then, we compare the performance of the proposed multiplexed architecture against a traditional single-beam downlink system that utilizes site diversity to mitigate cloud coverage effects. This comparison is based on two canonical scenarios, a global highly uncorrelated network representative of a geosynchronous satellite; and local, highly correlated, network representative of a low Earth orbit spacecraft. Through this analysis, we demonstrate that multiplexed architectures can improve the throughput of a space-to-ground optical network as compared to that of a single ground telescope without requiring a beam switching mechanism

    Architecting space communication networks under mission demand uncertainty

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    NASAs Space Network has been a successful program that has provided reliable communication and navigation services for three decades. As the third generation of satellites is being launched, alternatives to the current architecture of the system are being studied in order to improve the performance of the system, reduce its costs and facilitate its integration with the Near Earth Network and the Deep Space Network. Within this context, past research has proven the feasibility of efficiently exploring a large space of alternative network architectures using a tradespace search framework. Architecting a space communication network is a complex task that requires consideration of uncertainty, namely (1) factoring in customer demand variability, (2) predicting technology improvements and (3) considering possible budgetary constraints. This paper focuses on adding uncertainty associated with (1) to the existing communications network architecture tool by describing a heuristic-based model to derive mission concept of operations (conops) as a function of communication requirements. The accuracy of the model is assessed by comparing real conops from current TDRSS-supported missions with the predicted concept of operations. The model is used to analyze how customer forecast uncertainty affects the choice of the future network architecture. In particular, four customer scenarios are generated and compared with the current TDRSS capabilities.United States. National Aeronautics and Space Administration (NNX11AR70G

    Exploring changes in bacterial communities to assess the influence of fish farming on marine sediments

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    Changes in bacterial assemblages along an environmental gradient determined by the distance to aquaculture installations were analysed, using denaturing gradient gel electrophoresis to assess the influence of fish farming on marine sediments. Our findings show that changes in the structure of the bacterial community are a useful indicator for determining the environmental impact of aquaculture farms, due to the rapid response to changes in nutrient load, and could be an alternative strategy for monitoring programmes. Delta and Epsilonproteobacteria linked to the sulphur cycle were detected in the sediments beneath the cages. Since these groups were not found in the sediments at control stations, they serve as indicators for assessing the impact of the organic load from fish farming on marine sediments.This study forms part of the ‘Selección de indicadores, determinación de valores de referencia, diseño de programas y protocolos de métodos y medidas para estudios ambientales en acuicultura marina’ project funded by the ‘Spanish National Plans of Aquaculture’ (JACUMAR). The research was supported by Spanish Ministry of Economy and Competitiveness project CLG2015_66686-C3-3 (JA), which was also supported by financing from the European Regional Development Fund (FEDER). ERP thanks the Generalitat Valenciana for a postdoctoral grant (APOSTD-2016-091)

    Circulating miRNAs as Biomarkers of Obesity and Obesity-Associated Comorbidities in Children and Adolescents: A Systematic Review

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    Early detection of obesity and its associated comorbidities in children needs priority for the development of effective therapeutic intervention. Circulating miRNAs (microRNAs) have been proposed as biomarkers for obesity and its comorbidities; therefore, we conducted a systematic review to summarize results of studies that have quantified the profile of miRNAs in children and adolescents with obesity and/or associated disorders. Nine studies aiming to examine differences in miRNA expression levels between children with normal weight and obesity or between obese children with or without cardiometabolic diseases were included in this review. We identified four miRNAs overexpressed in obesity (miR-222, miR-142–3, miR-140-5p, and miR-143) and two miRNAs (miR-122 and miR-34a) overexpressed in children with obesity and nonalcoholic fatty liver disease (NAFLD) and/or insulin resistance. In conclusion, circulating miRNAs are promising diagnostic biomarkers of obesity-associated diseases such as NAFLD and type 2 diabetes already in childhood. However, more studies in children, using massive search technology and with larger sample sizes, are required to draw any firm conclusions.This research was funded by the Spanish Ministry of Industry and Competitiveness (DEP2016-78377-R) and by the European Regional Development Fund (ERDF), M.O. is supported by a grant from the Spanish Ministry of Economy and Competitiveness, grant number; BES-2017-080770 and the APC was funded by additional support from the University of Granada, UGR Research and Knowledge Transfer Fund (PPIT) 2016, Excellence Actions Programme, and Excellence Actions Programe. C.M.A. and I.L.G. are part of the “URG Plan propio de Investigación 2016” and the “Excellence actions: Unit of Excellence on Exercise and Health (UCEES), University of Granada

    The role of tropical dry forests for biodiversity, carbon and water conservation in the neotropics: lessons learned and opportunities for its sustainable management

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    In this paper, we provide a comprehensive evaluation of the current regional literature associated with tropical dry forest (TDF) along three main axes: biodiversity, carbon and water conservation in the neotropics. Our analysis provides three key findings: (1) from the biodiversity point of view, we document that high degrees of endemism, diversity of plant life forms and ecophysiological types as key elements for their conservation across the Americas, (2) from the carbon storage point of view, we found that if the world’s TDFs were restored they whole ecosystem would comprise 22 Pg of carbon in aboveground biomass. In the Americas alone, TDF restoration could potentially add 8 Pg of carbon to the potential total ecosystem carbon stock, (3) we found that at least 66 % of water reservoirs in the neotropics are located within dry forest ecoregions; therefore, the conservation of the quality of freshwater sources for human consumption in the neotropics is directly dependent on the sustainable management of TDF-dominated landscapes. In this paper, we stress that advocacy for conservation and sustainable management of TDF will benefit from integrating it’s value in biophysical terms (e.g. carbon, biodiversity) with key ecosystem services and uses (e.g. its impact on hydrological dynamics and its potential for fostering ecotourism initiatives and entrepreneurship). By doing this, support and awareness could be wider and more effective in the long term, especially from national and local communities. © 2014, Springer-Verlag Berlin Heidelberg

    A dense neural network approach for detecting clone ID attacks on the RPL protocol of the IoT

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    At present, new data sharing technologies, such as those used in the Internet of Things (IoT) paradigm, are being extensively adopted. For this reason, intelligent security controls have become imperative. According to good practices and security information standards, particularly those regarding security in depth, several defensive layers are required to protect information assets. Within the context of IoT cyber-attacks, it is fundamental to continuously adapt new detection mechanisms for growing IoT threats, specifically for those becoming more sophisticated within mesh networks, such as identity theft and cloning. Therefore, current applications, such as Intrusion Detection Systems (IDS), Intrusion Prevention Systems (IPS), and Security Information and Event Management Systems (SIEM), are becoming inadequate for accurately handling novel security incidents, due to their signature-based detection procedures using the matching and flagging of anomalous patterns. This project focuses on a seldom-investigated identity attack—the Clone ID attack—directed at the Routing Protocol for Low Power and Lossy Networks (RPL), the underlying technology for most IoT devices. Hence, a robust Artificial Intelligence-based protection framework is proposed, in order to tackle major identity impersonation attacks, which classical applications are prone to misidentifying. On this basis, unsupervised pre-training techniques are employed to select key characteristics from RPL network samples. Then, a Dense Neural Network (DNN) is trained to maximize deep feature engineering, with the aim of improving classification results to protect against malicious counterfeiting attempts

    Uncertainty quantification of network availability for networks of optical ground stations

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    This paper analyzes differences in the availability of networks of optical ground stations computed using different methods and datasets, and quantifies the uncertainty of the results. For that purpose, we first review existing methods proposed in the literature, and then existing cloud coverage datasets, and we compare the results obtained using different methods and datasets for several scenarios. Finally, we propose a new probabilistic global cloud coverage model that aggregates values from existing datasets and quantifies the uncertainty in measuring cloud probability, and present a method to compute the availability of a network of multiple optical ground stations, along with the corresponding uncertainty.Fundación Obra Social de La Caix

    A procedure to evaluate the resistance to biological colonization as a characteristic for product quality of ceramic roofing tiles

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    Abstract Ceramic roofing tiles suffer deterioration through time due to environmental exposure. Biological colonization affects the appearance and integrity of building materials, such as roofing tiles. The resistance to biocolonization represents an important property affecting the product quality of ceramic roofing tiles. While natural colonization of roofing tiles by organisms is a progressive, heterogeneous, and slow process, laboratory assessment of this phenomenon requires a sensitive procedure that can be carried out within a reasonable period of time. Different microorganisms have been evaluated and the use of phototrophs, specifically the cyanobacterium Oscillatoria, presented several advantages such as good adherence, homogeneous growth on surfaces, and the chlorophyll-autofluorescence which can be used for a sensitive detection. Colonization by Oscillatoria on roofing tiles was assessed by measuring the autofluorescence of cells. This study proposes the use of specific cyanobacterial cells and a simple method for monitoring biofilm formation and biological colonization of roofing tiles

    Variances in BCG protection against COVID-19 mortality: A global assessment

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    The BCG vaccine is known to impart nonspecific immunological benefits alongside conferring protection to tuberculosis in endemic regions. It is also known to protect against bladder cancer and other respiratory tract infections. During the coronavirus disease 2019 (COVID-19) pandemic, the BCG vaccine has gained attention due to its role in conferring protective immunity. We demonstrate the potential immunological protective mechanisms that play a role against COVID-19. We conduct a global assessment of the countries that have the highest and lowest mortality rates determined by an a priori methodology. Lastly, we discuss the potential limitations of incorporating BCG vaccines as potential strategies against COVID-19 and provide recommendations regarding their use in ongoing and future epidemics
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