36 research outputs found
Bulk Current Injection as an Alternative Radiated Susceptibility Test Enforcing a Statistically Quantified Overtesting Margin
No full textExperimental results are presented in support of the use of bulk current injection (BCI) as an alternative technique to unit-level radiated susceptibility (RS) verifications up to 1 GHz. The rationale for the correlation of BCI/RS test levels is grounded in the concept of overtesting (OT), which quantifies the excess of disturbances injected by BCI with respect to RS. Previous works showed that OT is a random variable, owing to unknown and uncontrolled setup parameters including the common-mode impedance of the equipment under test. The cumulative distribution function (cdf) of OT was shown to be predictable, by means of reasonable statistical assumptions and simple circuit models. This paper fills the gap between that simplified theoretical analysis and the complexity of real-world test setups. To this aim, an ad hoc structure mimicking typical wiring harness and equipment for aerospace applications is tested with BCI and RS to collect several results in terms of power injected/induced in the terminal units. The obtained datasets are processed to infer the empirical cdf of OT. Results are compared with theoretical predictions and properly discussed to point out the correlation between BCI and RS achieved in different test cases (vertical/horizontal antenna polarization, unshielded/shielded cables)
Experimental and Numerical Methods to Characterize Electrical Behaviour of Carbon Fiber Composites Used in Aeronautic Industry
No full textNon
Measuring Systemic and Climate Diversity in Ontario’s University Sector
No full textThis article proposes a methodology for measuring institutional diversity and applies it to Ontario’s university sector. This study first used hierarchical cluster analysis, which suggested there has been very little change in diversity between 1994 and 2010 as universities were clustered in three groups for both years. However, by adapting Birnbaum’s (1983) diversity matrix methodology to Ontario’s university sector, the author appears to have found a decrease in systemic diversity (differences in the type of institution and size of institution; Birnbaum, 1983) and climate diversity (differences in campus environment and culture; Birnbaum, 1983) between 1994 and 2010. Policy implications resulting from this study are also considered.
Cet article propose une méthodologie pour mesurer la diversité institutionnelle, et l’applique au secteur universitaire de l’Ontario. De prime abord, l’étude a utilisé une analyse de classification hiérarchique suggérant un faible taux de changement de diversité entre 1994 et 2010, période durant laquelle les universités se divisaient en trois groupes. Toutefois, en adaptant la méthodologie de mesure de la diversité de Birnbaum (1983) aux universités de l’Ontario, l’auteur semble avoir décelé une diminution de la diversité systémique (différence dans le type et la grandeur de l’institution, Birnbaum, 1983) et de la diversité climatique (différence dans l’environnement et la culture d’un campus, Birnbaum, 1983) entre 1994 et 2010. L’auteur a également pris en compte les effets de cette étude sur les politiques
Di piche e di ponte: le tecniche tradizionali di lavorazione | By piche and ponte: traditional working techniques
No full textIl lavoro è uno degli 8 capitoli, dei quali 5 dell’autore, risultato di un’attività di ricerca commissionata dal Consorzio Produttori Pietra Piasentina di Torreano (Ud), responsabile scientifico il prof. Mauro Bertagnin. In questo caso il tema affrontato è quello della lavorazione tradizionale della pietra pietra piasentina, brecciola calcarea eocenica usata in tutta l’area del Friuli orientale, con descrizione delle specificità delle tecniche di lavorazione manuale, tecniche tuttora utilizzate nelle realizzazioni artigianali, secondo pratiche di bottega tramandate di generazione in generazione. Il riferimento alle maestranze e al lavoro in cava e nei laboratori, precede la descrizione degli strumenti del mestiere e delle fasi della lavorazione, che vedono una ininterrotta continuità nei mezzi e nei modi dal Medioevo a metà ‘900. Il supporto di testimonianze, degli studi dei cultori locali e di riferimenti bibliografici legati alle ricerche della cultura materiale dell’area alpina permette di definire un quadro di riferimento che si è auspiacto essere esaustivo sul tema. | This work is one of eight chapters, including five by the author, resulting from research commissioned by the Consortium of Producers of Piasentina Stone in Torreano (Ud), directed by prof. Mauro Bertagnin. In this chapter, the topic is the traditional processing of Piasentina stone, the Eocene limestone used throughout the area of eastern Friuli, with a detailed description of the handworking techniques still used today in the workshops, based on skills handed down from generation to generation. A reference to the skilled trades and to the work in the quarries and the workshops is followed by a description of the tools of the trade and the processing stages, based on techniques which continued nearly unchanged in both means and method from the Middle Ages to the mid-1900s. The support of testimonies by the workers themselves, of studies by local scholars, and of bibliographic references on the material culture of this Alpine region has made it possible to define a framework that aims to be exhaustive on the subject
Flat Meta-Reflector for Broadband Circularly Polarized Parabolic Antenna
No full textInternational audienc
Exploring validation metrics for offline model-based optimisation with diffusion models
No full textIn model-based optimisation (MBO) we are interested in using machine learning
to design candidates that maximise some measure of reward with respect to a
black box function called the (ground truth) oracle, which is expensive to
compute since it involves executing a real world process. In offline MBO we
wish to do so without assuming access to such an oracle during training or
validation, with makes evaluation non-straightforward. While an approximation
to the ground oracle can be trained and used in place of it during model
validation to measure the mean reward over generated candidates, the evaluation
is approximate and vulnerable to adversarial examples. Measuring the mean
reward of generated candidates over this approximation is one such `validation
metric', whereas we are interested in a more fundamental question which is
finding which validation metrics correlate the most with the ground truth. This
involves proposing validation metrics and quantifying them over many datasets
for which the ground truth is known, for instance simulated environments. This
is encapsulated under our proposed evaluation framework which is also designed
to measure extrapolation, which is the ultimate goal behind leveraging
generative models for MBO. While our evaluation framework is model agnostic we
specifically evaluate denoising diffusion models due to their state-of-the-art
performance, as well as derive interesting insights such as ranking the most
effective validation metrics as well as discussing important hyperparameters
RFID equivalent model for prediction of functional and EMC performances in complex aeronautic environments
No full text
Evaluation of pre-molded coke produced from charcoal and eucalyptus tar
No full textO presente trabalho teve como objetivo produzir briquetes de carvão vegetal utilizando como aglutinantes diferentes tipos de piches de madeira e, posteriormente, avaliar o efeito desses aglutinantes, da temperatura final de coqueificação, da granulometria e da proporção de piche utilizada na mistura sobre a qualidade dos briquetes. Os seguintes parâmetros foram utilizados para a produção dos briquetes: quatro tipos de piches, duas granulometrias, duas proporções, duas temperaturas finais de coqueificação dos briquetes e uma pressão de compactação. A avaliação da qualidade dos briquetes foi feita por meio de análise química imediata, determinando-se os teores de matérias voláteis, cinzas e carbono fixo, as propriedades físico-mecânicas, densidade aparente, densidade verdadeira, porosidade, carga de ruptura e poder calorífico. Os resultados mostraram que os diferentes tipos de piches utilizados como aglutinantes apresentaram diferenças significativas entre si, em função do tratamento, mas todos apresentaram condições de ser utilizados como aglutinantes. A temperatura final de coqueificação foi o parâmetro mais importante na produção de briquetes, visto que influenciou significativamente algumas propriedades, como matérias voláteis, carbono fixo e poder calorífico. Os briquetes produzidos apresentaram baixos teores de matérias voláteis e cinzas, alto teor de carbono fixo, densidades aparente e verdadeira elevadas, cargas de ruptura superiores à do carvão vegetal e poder calorífico elevado.The aim of this work was producing charcoal briquettes using different types of wood tar as agglutinants, and evaluating the effect of tar type, final temperature of coking, granulometry and proportion of tar used in the mixture on quality of briquettes. The parameters used to produce the briquettes were: four types of tar, two granulometries, two proportions, two final temperatures of briquette coking and one compactation pressure. Their quality evaluation was made by an immediate chemical analysis, to determine the rate of volatile matters, ashes and fixed carbon, physical-mechanical properties, true and apparent densities, porosity, rupture load and heat capacity. The results showed that the different types of tar used as agglutinants were significantly different from each other due to the treatment, though all of them had presented conditions to be used as agglutinants. The final temperature of briquette coking was the most important parameter in the production, influencing significantly on properties like volatile matters, fixed carbon and heat capacity. The produced briquettes showed low rate of volatile matters and ash, high rate of fixed carbon, high true and apparent densities, rupture load higher than that of charcoal and high heat capacity
