65 research outputs found

    Use of supervised machine learning for GNSS signal spoofing detection with validation on real-world meaconing and spoofing data : part I

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    The vulnerability of the Global Navigation Satellite System (GNSS) open service signals to spoofing and meaconing poses a risk to the users of safety-of-life applications. This risk consists of using manipulated GNSS data for generating a position-velocity-timing solution without the user's system being aware, resulting in presented hazardous misleading information and signal integrity deterioration without an alarm being triggered. Among the number of proposed spoofing detection and mitigation techniques applied at different stages of the signal processing, we present a method for the cross-correlation monitoring of multiple and statistically significant GNSS observables and measurements that serve as an input for the supervised machine learning detection of potentially spoofed or meaconed GNSS signals. The results of two experiments are presented, in which laboratory-generated spoofing signals are used for training and verification within itself, while two different real-world spoofing and meaconing datasets were used for the validation of the supervised machine learning algorithms for the detection of the GNSS spoofing and meaconing

    Can increased vigilance for chronic kidney disease in hospitalised patients decrease late referral and improve dialysis-free survival?

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    Background: Insufficient vigilance for renal insufficiency is associated with late referral, increased morbidity and mortality. The present study examines whether increased vigilance for chronic kidney disease (CKD) leads to quicker referral to and better follow-up by a nephrologist, and whether it is associated with an improved outcome. Methods: Patients with an eGFR <45 ml/min/1.73 m(2) during hospitalisation at the Ghent University Hospital were enrolled during a period of 100 days. The patients were interviewed about their awareness of CKD. Both the patients and their general practitioner were subsequently informed about CKD. The primary endpoint was the number of patients referred for nephrological follow-up within three months. The secondary endpoint was need for dialysis and mortality from any cause one year after inclusion. Results: Of the 72 included patients, 54 had proven CKD, with eGFR consistently <45 ml/min/1.73 m2 during at least three months before inclusion. Merely 65% was aware of having CKD and only 41% was in regular nephrological follow-up. After intervention, the percentage of patients with CKD in follow-up increased from 41% to 71% (p = 0.002). The proportion reaching the secondary endpoint was significant lower in the patients who were referred quickly than in those who were not (p = 0.015). Similarly, the proportion was significant lower in the patients who received nephrological follow-up than in those who did not (p = 0.006). Conclusion: Vigilance for CKD is poor. Simple interventions to augment the vigilance for CKD, as presented in this study, lead to a quicker referral to and follow-up by a nephrologist, which may result in better outcome

    Disease suppression of potting mixes amended with composted biowaste

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    Peat mining destroys valuable nature areas and contributes to the greenhouse effect. This warrants the search for alternatives for peat in potting mixes. Composted biowaste could provide such an alternative. An additional advantage of (partially) replacing peat by compost is the increased disease suppressiveness. In this study, nine commercial composted biowastes were tested for disease suppressiveness using the pathosystems Pythium ultimum-cucumber, Phytophthora cinnamomi-lupin and Rhizoctonia solani-carrot. Increased disease suppression was found in compost-amended potting mixes for all three pathosystems. The level of disease suppression ranged from slight stimulation of disease to strong suppression. Suppressiveness against one disease was not well correlated with that against the other diseases. The CO2 production, a measure of general microbial activity, was the parameter most strongly correlated with the level of disease suppression. Wetsieving the biowaste with tap water over a 4-mm sieve prior to composting yielded a compost with an 2.4-fold increase in organic matter and a twofold decrease in EC and Cl--concentration of the compost. The latter reductions allow for an increase of the amount of peat that can be replaced by compost. A linear relation was found between the amount of compost added to the potting mix and the level of disease suppression indicating the potential for increasing disease suppressiveness of potting mixes by replacing peat by high-quality composted biowastes

    Use of supervised machine learning for GNSS signal spoofing detection with validation on real-world meaconing and spoofing data : part II

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    Global Navigation Satellite System (GNSS) meaconing and spoofing are being considered as the key threats to the Safety-of-Life (SoL) applications that mostly rely upon the use of open service (OS) signals without signal or data-level protection. While a number of pre and post correlation techniques have been proposed so far, possible utilization of the supervised machine learning algorithms to detect GNSS meaconing and spoofing is currently being examined. One of the supervised machine learning algorithms, the Support Vector Machine classification (C-SVM), is proposed for utilization at the GNSS receiver level due to fact that at that stage of signal processing, a number of measurements and observables exists. It is possible to establish the correlation pattern among those GNSS measurements and observables and monitor it with use of the C-SVM classification, the results of which we present in this paper. By adding the real-world spoofing and meaconing datasets to the laboratory-generated spoofing datasets at the training stage of the C-SVM, we complement the experiments and results obtained in Part I of this paper, where the training was conducted solely with the use of laboratory-generated spoofing datasets. In two experiments presented in this paper, the C-SVM algorithm was cross-fed with the real-world meaconing and spoofing datasets, such that the meaconing addition to the training was validated by the spoofing dataset, and vice versa. The comparative analysis of all four experiments presented in this paper shows promising results in two aspects: (i) the added value of the training dataset enrichment seems to be relevant for real-world GNSS signal manipulation attempt detection and (ii) the C-SVM-based approach seems to be promising for GNSS signal manipulation attempt detection, as well as in the context of potential federated learning applications

    Reproduction of Crassula helmsii by seed in western Europe

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    The amphibious plant species Crassula helmsii is a widely established and still-spreading alien in various parts of Europe, where it is considered invasive as its dense swards stress the viability of local biota. The species was considered to exclusively reproduce through vegetative means, until ex situ germination was recorded from a single locality in Belgium. We assessed whether this seed viability holds on a wider scale, by testing 16 populations from The Netherlands, Belgium, northern France, eastern England and northern Germany in a greenhouse germination experiment. Seedlings were observed from all populations but two, and from each of the five countries. Although most fruits were lacking seeds and the inferred germination percentages were overall low, germinable seed numbers are considerable given the high density of flowering stems. An in situ test revealed seeds to make it through normal winter conditions without signs of physical damage and with retention of germinability. Our results suggest that reproduction by seed is a relatively cryptic but widespread phenomenon throughout western Europe. The persistency of seed banks requires further investigation. Nonetheless, these findings already challenge the efficacy of techniques currently applied in C. helmsii control

    Fluxurile ISD in contextul crizei globale

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    Over time, foreign investments were the decisive factor contributing to the development of nations, but were the hardest hit during economic recessions. Under the circumstances of the world economy globalization and of the quasi-liberalization of international capital movements, leading to a high degree of financial markets interdependence, the impact of the crisis triggered in 2008 on FDI has been severe: decreased investment ability of companies, both on account of restricting access to financial resources and declining corporate profits; increased costs of financing on volatile international capital markets; reduced risk appetite of investors; deteriorated business climate; re-location of investments portfolio and the pressure of sovereign debts

    A Deployable Mast for Adaptable Textile Architecture

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    p. 252-263Proposed here is a concept for a deployable mast with angulated scissor units, for use in adaptable temporary architectural constructions. The adaptable structure serves as a tower or truss-like mast for a temporary tensile surface structure and doubles up as an active element during the erection process. The mast consists of scissor-like elements (SLE¿s) which are an effective way of introducing a single D.O.F.(degree of freedom) mechanism into a structure, providing it with the necessary kinematic properties for transforming from a compact state to a larger, expanded state. The scissor units used here are not comprised of straight bars, but rather consist of angulated elements, i.e. bars having a kink angle. Although primarily intended for radially deployable closed loop structures, it is shown in this paper that angulated elements can also prove valuable for use in a linear threedimensional scissor geometry.De Temmerman, N.; Mollaert, M.; De Laet, L.; Van Mele, T.; Guldentops, L.; Henrotay, C.; Debacker, W.... (2009). A Deployable Mast for Adaptable Textile Architecture. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/650

    Practical Tools to Implement Massive Parallel Pyrosequencing of PCR Products in Next Generation Molecular Diagnostics

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    Despite improvements in terms of sequence quality and price per basepair, Sanger sequencing remains restricted to screening of individual disease genes. The development of massively parallel sequencing (MPS) technologies heralded an era in which molecular diagnostics for multigenic disorders becomes reality. Here, we outline different PCR amplification based strategies for the screening of a multitude of genes in a patient cohort. We performed a thorough evaluation in terms of set-up, coverage and sequencing variants on the data of 10 GS-FLX experiments (over 200 patients). Crucially, we determined the actual coverage that is required for reliable diagnostic results using MPS, and provide a tool to calculate the number of patients that can be screened in a single run. Finally, we provide an overview of factors contributing to false negative or false positive mutation calls and suggest ways to maximize sensitivity and specificity, both important in a routine setting. By describing practical strategies for screening of multigenic disorders in a multitude of samples and providing answers to questions about minimum required coverage, the number of patients that can be screened in a single run and the factors that may affect sensitivity and specificity we hope to facilitate the implementation of MPS technology in molecular diagnostics

    Nutrition and the ageing brain: moving towards clinical applications

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    The global increases in life expectancy and population have resulted in a growing ageing population and with it a growing number of people living with age-related neurodegenerative conditions and dementia, shifting focus towards methods of prevention, with lifestyle approaches such as nutrition representing a promising avenue for further development. This overview summarises the main themes discussed during the 3 Symposium on "Nutrition for the Ageing Brain: Moving Towards Clinical Applications" held in Madrid in August 2018, enlarged with the current state of knowledge on how nutrition influences healthy ageing and gives recommendations regarding how the critical field of nutrition and neurodegeneration research should move forward into the future. Specific nutrients are discussed as well as the impact of multi-nutrient and whole diet approaches, showing particular promise to combatting the growing burden of age-related cognitive decline. The emergence of new avenues for exploring the role of diet in healthy ageing, such as the impact of the gut microbiome and development of new techniques (imaging measures of brain metabolism, metabolomics, biomarkers) are enabling researchers to approach finding answers to these questions. But the translation of these findings into clinical and public health contexts remains an obstacle due to significant shortcomings in nutrition research or pressure on the scientific community to communicate recommendations to the general public in a convincing and accessible way. Some promising programs exist but further investigation to improve our understanding of the mechanisms by which nutrition can improve brain health across the human lifespan is still required
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