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1
Wu, Lingling. "Surface processing by RFI PECVD and RFI PSII." W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539623997.
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An RFI plasma enhanced chemical vapor deposition (PECVD) system and a large-scale RF plasma source immersion ion implantation (PSII) system were designed and built to study two forms of 3-D surface processing, PECVD and PSII. Using the RFI PECVD system, Ti-6Al-4V substrates were coated with diamond-like carbon films with excellent tribological and optical properties. as an innovation, variable angle spectroscopic ellipsometry (VASE) was successfully applied for non-destructive, 3-D, large-area tribological coatings quality investigation.;Based on the experience with the RFI PECVD system, a large-scale RFICP source was designed and built for the PSIL Langmuir probe and optical emission spectroscopy studies indicated that the RFI source produced stable, uniform, and clean plasma. MAGIC code was for the first time used to model PSII process, addressing different target geometries and boundaries, materials, plasma parameters, illustrated sheath formation and evolution, field distribution, ion and electron trajectories, ion incident angles, and dose distributions, which are critical for PSII design and understanding.;The RF PSII system was developed into a versatile large-area, uniform, 3-D surface processing apparatus, capable of PSII, PVD, PECVD, and in situ surface cleaning and interface properties modification, for multilayer, multi-step, and high performance surface engineering. Using the RFI PSII system, for the first time, PSII was studied as a mask-based surface layer conversion technique, for pattern writing by implantation as an alternative to current deposition-based and ink-based direct write technologies. It operates at low substrate temperature, keeps the original surface finish and dimensions, and avoids adhesion problem. A different operating mode of the RF source was discovered to perform biased sputtering of high purity quartz, which turned the RFI PSII system into a novel integrated RF PSII/PVD system for large-area, uniform, nitrogen-doped, and hydrogen-free SiO2 films deposition at low substrate temperatures. Nitrogen-doped SiO2 films with excellent optical properties were deposited on semiconductor, metal, and polymer substrates with excellent adhesion. Ellipsometry was used again for non-destructive SiO2 coatings investigation. FEL test electrodes processed by PSII/PVD showed suppressed field emission. A group of transition metals and an FEL test electrode were also implanted by nitrogen using the PSII mode and analyzed.
2
Signé, Elisabeth. "Réactivité radicalaire de RFI, RFH et RFC2H4I : application à la synthèse." Montpellier 2, 1992. http://www.theses.fr/1992MON20253.
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Un chapitre bibliographique situe la reactivite radicalaire des composes r#fi, r#fh et r#fch#2ch#2i (r#f: c#nf#2#n#+#1 lineaire, n = 2,4,6,8). Il est ensuite decrit la synthese originale de r#fbr et r#fcl a partir de r#fi et r#fh mis en presence a 160 et 300c d'agents bromants et chlorants notamment cbr#4 et ccl#4 (chapitre 2). Enfin, une synthese amelioree de r#fch#2ch#2oh a pu etre effectuee par reaction de r#fch#2ch#2i avec des amides en presence d'initiateurs radicalaires (etudes cinetiques aspects mecanistique) (chapitre 3)
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Thompson, Nicholas Christopher. "RFI mitigation in radio astronomy." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86637.
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Thesis (MEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Technical advances in electromagnetics, signal processing and processing power have led to a significant increase in sensitivity and accuracy in radio telescopes. With this increase in sensitivity, radio frequency interference (RFI) has become a much larger problem. The notable growth in wireless communication as well as self generated RFI has further escalated this problem. In order to utilise the full capabilities of modern radio telescopes, RFI mitigation is required on the captured signals. With the enormous data rates of modern radio telescopes, managing RFI has become increasingly difficult, and in order to utilise the full captured radio spectrum, more accurate RFI mitigation strategies will be necessary. The use of different RFI mitigation strategies is studied in the form of online and offline techniques. This includes Spectral Kurtosis, Spectral Flatness and the Var/SumThreshold method. The special case for RFI mitigation in timing pulsars will also be studied. These techniques are well known in the radio astronomy community; here, spectral kurtosis and spectral flatness will be implemented on the raw data as well as the post correlated data. System speed and accuracy will be the deciding factors when testing these methods as possible solutions to this problem.
AFRIKAANSE OPSOMMING: ‘n Toename in die sensitiwiteit van hedendagse radioteleskope kan toegedra word aan die tegniese bevordering in elktromagnetika en seinverwerking. Die toename in sensitiwiteit het egter tot die gevolg dat radiofrekwensiesteuring ‘n groter rol speel in hedendaagse radioteleskope. Die groei in die gebruik van radioverbindings asook die gevolge van self gei¨nduseerde radiofrekwensiesteuring dra ook verder by tot hierdie probleem. Radiofrekwensiesteuring matiging word toegepas op die opgevangde seine, om sodoende gebruik te maak van die volle kapasiteit van moderne radioteleskope. Die bestuur van radiofrekwensiesteuring word bemoeilik deur die groot hoeveelheid intydse data van die radioteleskope. Meer akurate radiofrekwensiesteuring matigingstegnieke word vereis om die bandwydte ten volle te hanteer. Daar word op ‘n aantal verskillende matingstegnieke gefokus. Hierdie tegenieke kan in twee kategorieë verdeel word, naamlik aanlyn- en aflyntegenieke. Onderafdelings van hierdie kategorieë sluit in: spektrale kurtose, spektrale matheid en “Var/SumThreshold”. Daar word ook na ‘n spesiale geval van radiofrekwensiesteuring matiging gekyk, in die opmeeting van tydsberekening-pulsars. Alhoewel hierdie tegnieke bekend is in die radioastronomie gemeenskap, word spektrale kurtose en spektrale matheid egter toegepas op die rou data sowel as postgekorreleerde data. Daar sal op stelsel spoed en akuratheid gefokus word, om vas te stel of hierdie metodes wel moontlike oplossings bied tot die probleem bespreek.
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Czech, Daniel Josef. "Time domain classification of transient RFI." Doctoral thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/30071.
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Since the emergence of radio astronomy as a field, it has been afflicted by radio frequency interference (RFI). RFI continues to present a problem despite increasingly sophisticated countermeasures developed over the decades. Due to technological improvements, radio telescopes have become more sensitive (for example, MeerKAT’s L-band receiver). Existing RFI has become more prominent as a result. At the same time, the prevalence of RFI-generating devices has increased as new technologies have been adopted by society. Many approaches have been developed for mitigating RFI, which are typically used in concert. New telescope arrays are often built far from human habitation in radio-quiet reserves. In South Africa, a radio-quiet reserve has been established in which several world class instruments are under construction. Despite the remote location of the reserve, careful attention is paid to the possibility of RFI. For example, some instruments will begin observations while others are still under construction. The infrastructure and equipment related to the construction work may increase the risk of RFI, especially transient RFI. A number of mitigation strategies have been employed, including the use of fixed and mobile RFI monitoring stations. Such stations operate independently of the main telescope arrays and continuously monitor a wide bandwidth in all directions. They are capable of recording spectra and high resolution time domain captures of transient RFI. Once detected, and if identified, an RFI source can be found and dealt with. The ability to identify the sources of detected RFI would be highly beneficial. Continuous wave intentional transmissions (telecommunication signals for example) are easily identified as they are required to adhere to allocated frequency bands. Transient RFI signals, however, are significantly more challenging to identify since they are generally broadband and highly intermittent. Transient RFI can be generated as a by-product of the normal operation of devices such as relays, AC machines and fluorescent lights, for example. Such devices may be present near radio telescope arrays as part of the infrastructure or equipment involved in the construction of new instruments. Other than contaminating observation data, transient RFI can also appear to have genuine astronomical origins. In one case, transient signals received from a microwave oven exhibited dispersion, suggesting a distant source. Therefore, the ability to identify transient RFI by source would be enormously valuable. Once identified, such sources may be removed or replaced where possible. Despite this need, there is a paucity of work on classifying transient RFI in the literature. This thesis focusses on the problem of identifying transient RFI by source in time domain data of the type captured by remote monitoring stations. Several novel approaches are explored in this thesis. If used with independent RFI monitoring stations, these approaches may aid in tracking down nearby RFI sources at a radio telescope array. They may also be useful for improving RFI flagging in data from radio telescopes themselves. Distinguishing between transient RFI and natural astronomical signals is likely to be an easier prospect than classifying transient RFI by source. Furthermore, these approaches may be better able to avoid excising genuine astronomical transients that nevertheless share some characteristics with RFI signals. The radio telescopes themselves are significantly more sensitive than RFI monitoring stations, and would thus be able to detect RFI sources more easily. However, terrestrial RFI would likely enter via sidelobes, tempering this advantage somewhat. In this thesis, transient RFI is first characterised, prior to classification by source. Labelled time-domain recordings of a number of transient RFI sources are acquired and statistically examined. Second, components analysis techniques are considered for feature selection. Cluster separation is analysed for principal components analysis (PCA) and kernel PCA, the latter proving most suitable. The effect of the supply voltage of certain RFI sources on cluster separation in the principal components domain is also explored. Several na¨ıve classification algorithms are tested, using kernel PCA for feature selection A more sophisticated dictionary-based approach is developed next. While there are variations in repeated recordings of the same RFI source, the signals tend to adhere to a common overarching structure. Full RFI signals are observed to consist of sequences of individual transients. An algorithm is presented to extract individual transients from full recordings, after which they are labelled using unsupervised clustering methods. This procedure results in a dictionary of archetypal transients, from which any full RFI sequence may be represented. Some approaches in Automated Speech Recognition (ASR) are similar: spoken words are divided into individual labelled phonemes. Representing RFI signals as sequences enables the use of hidden Markov models (HMMs) for identification. HMMs are well suited to sequence identification problems, and are known for their robustness to variation. For example, in ASR, HMMs are able to handle the variations in repeated utterances of the same word. When classifying the recorded RFI signals, good accuracy is achieved, improving on the results obtained using the more na¨ıve methods. Finally, a strategy involving deep learning techniques is explored. Recurrent neural networks and convolutional neural networks (CNNs) have shown great promise in a wide variety of classification tasks. Here, a model is developed that includes a pre-trained CNN layer followed by a bidirectional long short-term memory (BLSTM) layer. Special attention is paid to mitigating class imbalance when the model is used with individual transients extracted from full recordings. High classification accuracy is achieved, improving on the dictionary-based approach and the other na¨ıve methods. Recommendations are made for future work on developing these approaches further for practical use with remote monitoring stations. Other possibilities for future research are also discussed, including testing the robustness of the proposed approaches. They may also prove useful for RFI excision in observation data from radio telescopes.
5
Schollar, Christopher. "RFI Monitoring for the MeerKAT Radio Telescope." Thesis, University of Cape Town, 2015. http://pubs.cs.uct.ac.za/archive/00001042/.
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South Africa is currently building MeerKAT, a 64 dish radio telescope array, as a pre-cursor for the proposed Square Kilometre Array (SKA). Both telescopes will be located at a remote site in the Karoo with a low level of Radio Frequency Interference (RFI). It is important to maintain a low level of RFI to ensure that MeerKAT has an unobstructed view of the universe across its bandwidth. The only way to effectively manage the environment is with a record of RFI around the telescope.
The RFI management team on the MeerKAT site has multiple tools for monitoring RFI. There is a 7 dish radio telescope array called KAT7 which is used for bi-weekly RFI scans on the horizon. The team has two RFI trailers which provide a mobile spectrum and transient measurement system. They also have commercial handheld spectrum analysers. Most of these tools are only used sporadically during RFI measurement campaigns. None of the tools provided a continuous record of the environment and none of them perform automatic RFI detection.
Here we design and implement an automatic, continuous RFI monitoring solution for MeerKAT. The monitor consists of an auxiliary antenna on site which continuously captures and stores radio spectra. The statistics of the spectra describe the radio frequency environment and identify potential RFI sources. All of the stored RFI data is accessible over the web. Users can view the data using interactive visualisations or download the raw data. The monitor thus provides a continuous record of the RF environment, automatically detects RFI and makes this information easily accessible.
This RFI monitor functioned successfully for over a year with minimal human intervention. The monitor assisted RFI management on site during RFI campaigns. The data has proved to be accurate, the RFI detection algorithm shown to be effective and the web visualisations have been tested by MeerKAT engineers and astronomers and proven to be useful. The monitor represents a clear improvement over previous monitoring solutions used by MeerKAT and is an effective site management tool.
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Moore, Thomas Dean. "Analytic Study of Space-Time and Space-Frequency Adaptive Processing for Radio Frequency Interference Suppression." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1037380239.
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Lefebvre, Pierre D. "Adaptive multiple sub-band common mode RFI suppression." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58475.pdf.
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Mngadi, Andile. "L-band RFI measurement system simulation and investigation." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/5158.
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Includes bibliographical references (leaves 53-54)The Square Kilometre Array (SKA) is a multi billion dollar international project to create a receiving surface of a million square metres, one hundred times larger than the biggest receiving surface now in existence. The SKA core array will have to be located in a remote area. Therefore countries interested in hosting the SKA core array were requested to perform Radio Frequency Interference measurements at their site of choice. The systems that are to be used in the measurements must conform to a document called the "RFI Measurement Protocol for Candidates SKA Sites", the SKA Memo 37. The RFI protocol divides measurements into two parts, Mode 1 and Mode 2. Mode 1 is defined for the observation of strong RFI and is relevant for SKA receiver linearity analysis. Mode 2 is defined for the observation of weak interferences, which potentially threatens to obscure weak signals of interest. In Mode 1, the RFI protocol specifies a dwell time of 2μS duration over a large 1 MHz bandwidth in the 960 -1400 MHz band (L-band). The reason for this short dwell time is to capture and characterize pulsed interference from radars and Distance Measuring Equipment (DME) in this band. This kind of interference is expected, potentially with very high peak power and short dwell time. Executing these measurements with the spectrum analyzer is impractical because of the very long measurement times. It was therefore proposed to build a dedicated FFT spectrometer from standard components, state of the art FPGA board with a high speed 14 bit ADC.
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Dong, Weizhen. "Time Blanking for GBT Data with RADAR RFI." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd468.pdf.
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Staats, Kai. "Genetic programming applied to RFI mitigation in radio astronomy." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/23703.
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Genetic Programming is a type of machine learning that employs a stochastic search of a solutions space, genetic operators, a fitness function, and multiple generations of evolved programs to resolve a user-defined task, such as the classification of data. At the time of this research, the application of machine learning to radio astronomy was relatively new, with a limited number of publications on the subject. Genetic Programming had never been applied, and as such, was a novel approach to this challenging arena. Foundational to this body of research, the application Karoo GP was developed in the programming language Python following the fundamentals of tree-based Genetic Programming described in "A Field Guide to Genetic Programming" by Poli, et al. Karoo GP was tasked with the classification of data points as signal or radio frequency interference (RFI) generated by instruments and machinery which makes challenging astronomers' ability to discern the desired targets. The training data was derived from the output of an observation run of the KAT-7 radio telescope array built by the South African Square Kilometre Array (SKA-SA). Karoo GP, kNN, and SVM were comparatively employed, the outcome of which provided noteworthy correlations between input parameters, the complexity of the evolved hypotheses, and performance of raw data versus engineered features. This dissertation includes description of novel approaches to GP, such as upper and lower limits to the size of syntax trees, an auto-scaling multiclass classifier, and a Numpy array element manager. In addition to the research conducted at the SKA-SA, it is described how Karoo GP was applied to fine-tuning parameters of a weather prediction model at the South African Astronomical Observatory (SAAO), to glitch classification at the Laser Interferometer Gravitational-wave Observatory (LIGO), and to astro-particle physics at The Ohio State University.
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Dunn, Sydney Bobby. "A study of the SA SKA RFI measurement systems." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/5275.
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Includes bibliographical references (leaves 85-90).This dessertation documents the findings of a study of the functionality of RFI Measurement System 2 that was conducted by the author. An in depth study of MEMO 37 (RFI Measurement Protocol) was employed first. After which, an exhaustive audit of all the equipment used and a thorough analysis of the method of data collection and processing was conducted. A sample of raw uncalibrated, MODE 1 field measurement data was scrutinized.
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Manners, Paul John. "Measuring the RFI environment of the South African SKA site." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1005259.
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The Square Kilometre Array (SKA) Project is an international effort to build the world’s largest radio telescope. It will be 100 times more sensitive than any other radio telescope currently in existence and will consist of thousands of dishes placed at baselines up to 3000 km. In addition to its increased sensitivity it will operate over a very wide frequency range (current specification is 100 MHz - 22 GHz) and will use frequency bands not primarily allocated to radio astronomy. Because of this the telescope needs to be located at a site with low levels of radio frequency interference (RFI). This implies a site that is remote and away from human activity. In bidding to host the SKA, South Africa was required to conduct an RFI survey at its proposed site for a period of 12 months. Apart from this core site, where more than half the SKA dishes may potentially be deployed, the measurement of remote sites in Southern Africa was also required. To conduct measurements at these sites, three mobile measurement systems were designed and built by the South African SKA Project. The design considerations, implementation and RFI measurements recorded during this campaign will be the focus for this dissertation.
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Bingham, Glenda Marie. "The relationship between residual feed intake and feeding behavior in growing heifers." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1412.
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Ben, Khadher Mohamed Mohsen. "Étude des interférences sur les mesures micro-ondes passives en bande L à l’aide de radiomètres au sol et aéroportés." Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10549.
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Certaines données satellitaires ne sont pas utilisées à cause des acquisitions bruitées qui ne reflètent pas les distributions des grandeurs géophysiques du sol, telle que l’humidité du sol. La cause primordiale dans les micro-ondes passives vient des interférences radio fréquence (RFI). Ainsi, les températures apparentes mesurées par un satellite comme SMOS par exemple atteignent souvent des valeurs qui conduisent à des échecs d’inversion de l’humidité du sol. L’objectif de notre projet est d’étudier le phénomène des RFI à petite échelle, son impact sur les micro-ondes passives en bande L à partir des mesures au sol réalisées à l’aide de radiomètres. Une fois l’impact caractérisé de manière rigoureuse, une méthode de filtrage adaptatif a été développée pour corriger les effets.
Le projet est composé de trois parties principales. La mise en place d’une expérimentation est réalisée afin de faire des mesures au sol à l’aide de deux radiomètres en bande L. Les mesures sont faites dans des conditions variables et plusieurs scénarios ont été considérés. Ensuite, les données sont collectées et analysées. Cette phase a abouti au développement d’un filtre qui permet d’atténuer l’effet des RFI sur les températures de brillance bruitées. Enfin, le filtre proposé dans le projet a été appliqué sur des données aéroportées en bande L prises sur le site Boreal Ecosystem Research and Monitoring Sites (BERMS) en Saskatchewan.
L’expérimentation s’est déroulée à la station SIRENE de l’Université de Sherbrooke. Les instruments ont été mis en place et les radiomètres ont été calibrés en premier lieu pour s’assurer de la fiabilité des mesures. L’émetteur a servi comme une source d’interférence pour les radiomètres. Il était placé à des positions différentes vis-à-vis de ces derniers, et émettait à des puissances variables. Les différents scénarios considérés étaient utiles pour étudier l’effet de la position de la source RFI, ainsi que l’effet de la puissance émise par celle-là sur les températures mesurées par les radiomètres. Pour les mesures, nous avons utilisé un radiomètre multi-bandes qui nous a permis d’étudier l’impact de la bande passante sur les RFI.
L’analyse et le traitement des données prises ont conduit au développement d’un filtre coupe-bande permettant de corriger les températures bruitées lorsque les caractéristiques du bruit sont connues. Ce filtre a été appliqué sur des données aéroportées bruitées. Le bruit a pu être atténué pour les températures en polarisation V. Les résultats de l’application du filtre sont satisfaisants dans l’ensemble malgré le volume important de données bruitées sur la zone d’étude. En ce qui concerne les données de la polarisation H, elles n’ont pu être corrigées, car elles étaient presque entièrement bruitées.
Le mémoire porte sur une expérimentation originale, car les expériences du genre sont très rares dans la littérature. L’étude s’appuie sur deux radiomètres en bande L, ce qui est très particulier, compte tenu de la rareté de ces instruments.
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Van, der Merwe Carel. "Culprit and victim management RFI environment for a radio astronomy site." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/19987.
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Thesis (MScEng)--Stellenbosch University, 2012.ENGLISH ABSTRACT: A methodology is developed to manage the large number of RFI Culprits on a new Radio Telescope location such as the South African site being developed in the Karoo, both during construction and ongoing operations. The requirement for RFI control is presented, with brief reference to the more traditional methods used by other Radio Telescope observatories. The new approach is then presented, based on methods used in the engineering field of Logistic Engineering. Three case studies are used to illustrate how the approach can be applied. Finally, recommendations are made on how the approach can be implemented for new Radio Telescope projects.
AFRIKAANSE OPSOMMING: ‘n Metodolgie word ontwikkel vir die beheer van die groot aantal Radiofrekwensiesteurings oortreders by ‘n nuwe Radio Teleskoop terrein, soos die Suid Afrikaanse terrein wat huidiglik in die Karoo ontwikkel word. Die metodolgie geld beide gedurende konstruksie en gedurende bedryf. Die behoefte vir RFS beheer word aangebied, met kortlikse melding van die meer tradisionele metodes wat ander Radio Teleskoop Sterrewagte gebruik. ‘n Nuwe aanslag, gebaseer op die metodolgieë van Logistieke Ingenieurswese, word dan aangebied. Drie gevallestudies wys hoe hierdie nuwe aanslag toegepas kan word. Laastens word aanbevelings gemaak om hierdie nuwe aanslag met nuwe Radio Teleskoop projekte te implimenteer.
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Ridgeway, Robert. "A Light Weight, RF Anechoic Chamber for EMP & RFI Shielding." International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595780.
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Mikros, Efthimios. "Mitigation of EMI/RFI produced by a 1.2 kW uninterruptible power supply." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from the National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA273149.
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Thesis (M.S. in Systems Engineering) Naval Postgraduate School, September 1993.Thesis advisor(s): Adler, Richard William. "September 1993." Includes bibliographical references. Also available online.
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Gowans, James Zekkai Middlemost. "Design and Implementation of an RFI Direction Finding System for SKA Applications." Master's thesis, Faculty of Engineering and the Built Environment, 2021. http://hdl.handle.net/11427/33701.
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For radio astronomy telescopes to be able to perform observations of weak signals from space, they need to operate in a radio-quiet environment. Any radio frequency interference (RFI) will interfere with the ability of the telescope to collect data. With the proliferation of electrical and electronic devices, RFI management is one of the major challenges facing radio astronomy reserves. This thesis details the design, construction and testing of a system which is able to find the direction which a source of interference is coming from. User requirements for the system are captured, and one of the key requirement of the system is the ability to direction-find two classes of RFI: weak narrow-band continuous signals, and strong impulsive signals. Both of these classes of signals pose problems for radio telescopes. The primary focus of the thesis is implementing the algorithms to direction find those signals, and to evaluate whether the algorithms perform as expected on real RFI sources in the field. An analysis of various prior direction finding techniques is done from the existing literature to select the most suitable technique for this system. A combination of phase interferometry and time difference of arrival is selected, due to their suitability for the classes of signals, the operating environment and the hardware that will be used. Simulations are done showing how the system should operate and to highlight potential challenges. A key challenge is around phase ambiguity, and special attention is paid to mitigating this. After design and simulation, a full system is implemented containing a number of subsystems linked together. A four element deformed circular antenna array and RF front end pick up signals from the environment. These signals are digitised together in phase by fast analogue to digital converters (ADCs). The output of the ADCs goes into a field programmable gate array (FPGA) on a ROACH development board which does high speed DSP including Fourier transforms, spectrum cross correlations, accumulations, power detections and time domain capturing. The output of the Digital Signal Processing (DSP) done on the FGPA is received by a computer running a Python application which performs the final angle of arrival calculations in real time. The application has a mathematical model of the antenna array which it combines with the received baseline time difference or phase shift measurements to ascertain the direction of the signal source. When designing and building the system, emphasis is put in making it flexible and reconfigurable, allowing it to be used with arbitrary array configurations or frequency ranges. The system is first put together and tested in the lab using signal generators, noise sources and impulse generators. These signals are fed into the ROACH board to simulate an RF environment and hence ensure that the design is working as expected. Next, the system is made portable and taken out for field trials. The field trials demonstrate that the system is able to provide accurate tracks for a number of different RFI sources, both impulsive and narrowband. It is able to maintain a track over the full 360◦ field of view as required.
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McDonald, Tyrel James. "Searching for the ultimate cow the economic value of RFI at bull sales /." Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/mcdonald/McDonaldT0510.pdf.
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Selecting cattle that consume less feed without production losses can increase the profitability of cow/calf producers by reducing input costs. However, genetic selection based on historical measures of feed efficiency or feed to gain ratios (F:G) is unable to improve this trait because of correlations between feed efficiencies and gain traits. Residual feed intake (RFI) is an alternative measure of feed efficiency that is independent of body weight (BW) and growth traits. RFI is the difference between an animal's actual feed intake and expected feed intake. For example, an animal that consumes 3 pounds less feed than expected would be assigned a RFI of -3 and is considered more feed efficient than those with larger RFI measures. Seed stock producers sell bulls to cow/calf producers. Cow/calf producers select bulls that are perceived to have the greatest potential to improve the genetics of breeding cows and/or their offspring. Bull sales often provide sale catalogs to potential buyers that contain various performance measures including expected progeny differences (EPDs) and simple performance measures (SPMs). These measures provide information to purchasers so that rational decisions regarding genetic improvements can be made. Midland Bull Test (MBT) in Columbus, MT conducts bull performance tests on 1,200 bulls annually for bull producers throughout the Unites States. In 2008 and 2009, MBT used a new technology (GrowSafe) to record individual feed intake which allows for the calculation of RFI. These measures, along with performance EPDs, provide the basis for a linear hedonic price model to determine if bull purchasers value RFI. Regression results indicate buyers are willing to pay additional amounts for bulls that are RFI efficient. However, buyers appear to be valuing RFI below its theoretical contribution to cost reductions because of risk and uncertainty. Purchasers at the MBT bull sales valued gain traits, birth weight, and age more highly than RFI. If this behavior is consistent in other markets and buyers continue to value RFI, it would be reasonable to expect an RFI EPD to be developed in the future.
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Jones, Aaron M. "Performance Prediction of Constrained Waveform Design for Adaptive Radar." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1467821668.
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Chumpitaz, Brayan, Junior Rubio, Sandra Rodriguez, and Alexandra Hinostroza. "Application of the scrum framework to optimize time in construction projects." Institute of Electrical and Electronics Engineers Inc, 2020. http://hdl.handle.net/10757/656412.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.Currently, the construction industry is characterized by a high competition between its companies. Due to this, companies must guarantee that the performance of their projects is possible by using an appropriate management system which allows an adequate planning of activities, since selecting an inadequate system can cause serious inconveniences such as having rework and increase cost and time in projects. Therefore, the construction industry is constantly searching for management models that can minimize the previously mentioned inconveniences in order to differentiate themselves and take advantage of their competitors. Precisely, the Scrum framework, conceived in the software engineering industry, is an alternative to traditional projects management, offering an exponential improvement in communication for project teams and improving the planning of activities, through an iterative framework that allows flexibility for changing requirements, reduces uncertainty and creates reliability for what was planned. Thus, this research adapts and applies the Scrum framework within a construction project, optimizing considerably the execution time.
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Shvaichenko, V., V. Bakiko, D. Titkov, and Othman Sharadjah. "EMC method for audio broadcast in large rooms." Thesis, Київський національний університет технологій та дизайну, 2018. https://er.knutd.edu.ua/handle/123456789/9689.
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Mitchell, Daniel Allan. "Interference Mitigation in Radio Astronomy." Thesis, The University of Sydney, 2004. http://hdl.handle.net/2123/693.
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This thesis investigates techniques and algorithms for mitigating radio frequency interference (RFI) affecting radio astronomy observations. In the past radio astronomy has generally been performed in radio-quiet geographical locations and unused parts of the radio spectrum, including small protected frequency bands. The increasing use of the entire spectrum and global transmitters such as satellites are forcing the astronomy community to begin implementing active interference cancelling. The amount of harmful interference affecting observations will also increase as future instruments such as the Square Kilometre Array (SKA) are required to use larger bandwidths to reach up to 100 times the current sensitivity levels, and as spectral line observations require observing in bands licensed to other spectrum users. Particular attention is paid to interference cancellation algorithms which make use of reference beams. This has proven to be successful in removing interference from the contaminated astronomical data. Reference antenna cancellers are closely analysed, leading to filters and techniques that can offer improved RFI excision for some important applications. It is shown that pre- and post-correlation reference antenna cancellers give similar results, and an important aspect of the cancellers is the use of a second reference signal when the reference interference-to-noise ratio is low. These modified filters can theoretically offer infinite interference suppression in the voltage domain, equivalent to that of post-correlation interference cancellers, and their internal structure can offer an understanding of the residual RFI and added receiver noise components of a variety of reference antenna techniques. The effect of variable geometric delays is also considered and various filters are compared as a function of the geometric fringe rate.
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Mitchell, Daniel Allan. "Interference Mitigation in Radio Astronomy." University of Sydney. Physics, 2004. http://hdl.handle.net/2123/693.
Full textAbstract:
This thesis investigates techniques and algorithms for mitigating radio frequency interference (RFI) affecting radio astronomy observations. In the past radio astronomy has generally been performed in radio-quiet geographical locations and unused parts of the radio spectrum, including small protected frequency bands. The increasing use of the entire spectrum and global transmitters such as satellites are forcing the astronomy community to begin implementing active interference cancelling. The amount of harmful interference affecting observations will also increase as future instruments such as the Square Kilometre Array (SKA) are required to use larger bandwidths to reach up to 100 times the current sensitivity levels, and as spectral line observations require observing in bands licensed to other spectrum users. Particular attention is paid to interference cancellation algorithms which make use of reference beams. This has proven to be successful in removing interference from the contaminated astronomical data. Reference antenna cancellers are closely analysed, leading to filters and techniques that can offer improved RFI excision for some important applications. It is shown that pre- and post-correlation reference antenna cancellers give similar results, and an important aspect of the cancellers is the use of a second reference signal when the reference interference-to-noise ratio is low. These modified filters can theoretically offer infinite interference suppression in the voltage domain, equivalent to that of post-correlation interference cancellers, and their internal structure can offer an understanding of the residual RFI and added receiver noise components of a variety of reference antenna techniques. The effect of variable geometric delays is also considered and various filters are compared as a function of the geometric fringe rate.
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Yang, Yue. "Thermal Conductivity of Carbon Fibre Fabrics and Multi-Scale Composites with Heat Transfer Simulations for RFI Manufacturing." Thesis, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30252.
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Composites are increasingly used in aerospace applications where performance is the
foremost priority of industry. Research on carbon nanotube (CNT)-reinforced polymers
conducted in the past decade showed promising results for the improvement of mechanical,
thermal and electrical properties of composites. This thesis was undertaken in the context of
a larger project, the main goal of which is to develop a complete solution for the
manufacturing of carbon fibre-epoxy composites using CNT-reinforced epoxies, referred to
as multi-scale composites. This thesis focuses on the thermal aspect of this project under
three topics: 1) thermal conductivity of dry carbon fibre fabrics for understanding heat
diffusion in composites and similar fabric materials 2) thermal conductivity of CNTreinforced
polymers and composites for determining the effect of parameters including CNT
addition, and 3) modelling of heat transfer during composite manufacturing for ensuring that
their temperature distribution remains controlled.
In-plane k rip and through-thickness k rtt thermal conductivity data were measured for
two dry carbon fibre fabrics as a function of fibre volume fraction Vf . Results showed that
k rip varies linearly with Vf whilst k rtt varies in an exponential recovery trend with Vf . An
existing analytical model was used successfully for predicting k rip and simulations developed
for predicting k rtt values demonstrated that k rtt depends on the evolution of heat conduction
paths in the through-thickness direction as a result of improvements in the fibre contact
network.
A procedure was developed for manufacturing composites using the RFI process.
Thirty-two composites and multi-scale composite plates were manufactured and
characterised for investigating the effects of eleven material and manufacturing parameters
on fibre volume fraction, porosity, k rip and k rtt . Results showed that the effect of using
multi-walled CNT-reinforced epoxy on thermal conductivity of composites is negligible at
0.3% CNT loading. However, this reduced the porosity of the composites significantly.
Results also showed that using fabrics with higher surface densities led to a slight increase in
k cip .
A heat transfer model coupled with cure kinetics was developed for predicting
temperature profiles of the laminate during RFI manufacturing. The model was validated
experimentally and eleven simulation cases were run for investigating the effects of five
material and manufacturing parameters on temperature profiles in the laminate. Results
showed that the epoxy resins used in this project combined with the cure cycle recommended
by the manufacturer are well-suited for manufacturing laminates with a typical thickness of
approximately 5 mm as well as thick laminates of 15 mm to 20 mm.
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Thompson, Joseph E. "Compaction and Cure of Resin Film Infusion Prepregs." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/36479.
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Gutowski et al.'s model has been employed to describe the cure and consolidation of prepregs used for resin film infusion. Resin kinetics, rheology, flow and fiber deformation are considered. Resin kinetics are simulated with an isothermal autocatalytic-1 type relation. The non-Newtonian viscosity of the Cytec™ 754 resin is represented with a gel type expression. The one dimensional flow of resin through a deformable, partially saturated porous medium is studied. A nonlinear partial differential equation describing the spatial and temporal variation of the fiber volume fraction combining the continuity equation, Darcy's Law, and mat compressibility has been derived and solved numerically. Resin is assumed to be incompressible and inertial effects are neglected. Based on the resin content of regions where resin and fiber coexist, expressions for tracking resin flow through fully and partially saturated regions of fiber are given. Values of material parameters for the E-QX 3600-5 glass fabric are estimated from literature data involving compression of similar dry fabrics and through comparison of computed results with the experimental data. Results for the final thickness of the consolidated part agree with the experimental values, but those for the mass loss do not.Master of Science
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Stemmons, Alan Joseph. "Radio Frequency Interference Mitigation on the Very Small Array." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1856.
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Radio astronomical synthesis imaging arrays can create images with resolution much higher than can single dish telescopes. However, one of the biggest problems that imaging arrays face is radio frequency interference (RFI). This interference corrupts signals and prevents accurate image creation. Therefore, it is necessary to remove this interference. This thesis discusses the synthesis imaging procedure and array spatial filtering methods to remove interference, including Multiple Sidelobe Canceller (MSC), Subspace Projection (SP), and Cross-Subspace Projection (CSP). The CLEAN algorithm, an image restoration technique, is also discussed. Various improvements to the VSA are discussed, including upgrades to the hardware and software and addition of a fifth antenna to the array. Calibration techniques for the VSA are presented. Successful image synthesis for deep-space sources of Cassiopeia A and Cygnus A are shown and phase errors that have caused difficulties with imaging are considered. The previously mentioned algorithms are successfully applied to data gathered by the Very Small Array (VSA), allowing images to be created in environments with interference. An improved method for bias correction for both SP and CSP is demonstrated. The CLEAN algorithm is demonstrated on two different images.
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Kelly, Shaun Innes. "Iterative synthetic aperture radar imaging algorithms." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9368.
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Synthetic aperture radar is an important tool in a wide range of civilian and military imaging applications. This is primarily due to its ability to image in all weather conditions, during both the day and the night, unlike optical imaging systems. A synthetic aperture radar system contains a step which is not present in an optical imaging system, this is image formation. This is required because the acquired data from the radar sensor does not directly correspond to the image. Instead, to form an image, the system must solve an inverse problem. In conventional scenarios, this inverse problem is relatively straight forward and a matched lter based algorithm produces an image of suitable image quality. However, there are a number of interesting scenarios where this is not the case. Scenarios where standard image formation algorithms are unsuitable include systems with data undersampling, errors in the system observation model and data that is corrupted by radio frequency interference. Image formation in these scenarios will form the topics of this thesis and a number of iterative algorithms are proposed to achieve image formation. The motivation for these proposed algorithms is primarily from the eld of compressed sensing, which considers the recovery of signals with a low-dimensional structure. The rst contribution of this thesis is the development of fast algorithms for the system observation model and its adjoint. These algorithms are required by large-scale gradient based iterative algorithms for image formation. The proposed algorithms are based on existing fast back-projection algorithms, however, a new decimation strategy is proposed which is more suitable for some applications. The second contribution is the development of a framework for iterative near- eld image formation, which uses the proposed fast algorithms. It is shown that the framework can be used, in some scenarios, to improve the visual quality of images formed from fully sampled data and undersampled data, when compared to images formed using matched lter based algorithms. The third contribution concerns errors in the system observation model. Algorithms that correct these errors are commonly referred to as autofocus algorithms. It is shown that conventional autofocus algorithms, which work as a post-processor on the formed image, are unsuitable for undersampled data. Instead an autofocus algorithm is proposed which corrects errors within the iterative image formation procedure. The proposed algorithm is provably stable and convergent with a faster convergence rate than previous approaches. The nal contribution is an algorithm for ultra-wideband synthetic aperture radar image formation. Due to the large spectrum over which the ultra-wideband signal is transmitted, there is likely to be many other users operating within the same spectrum. These users can produce signi cant radio frequency interference which will corrupt the received data. The proposed algorithm uses knowledge of the RFI spectrum to minimise the e ect of the RFI on the formed image.
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Shvaichenko, V., A. Makarov, and O. Sharadjah. "Possibilities of limiting RF interference in the low-frequency range by intelligent means to EMC ensure." Thesis, Київський національний університет технологій та дизайну, 2017. https://er.knutd.edu.ua/handle/123456789/6674.
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Vittin, Théophile E. "Les Radios internationales en Afrique noire : l'exemple de RFI dans les pays francophones (avec référence au cas du Bénin)." Bordeaux 3, 1995. http://www.theses.fr/1995BOR30049.
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Par-delà les clichés et controverses liées aux actions des radios internationales en Afrique noire, l'impact de ces stations obéit à des motivations et usages spécifiques aussi bien de la part des émetteurs de des récepteurs, ainsi qu'à des motifs d'ordre interne et externe, ce qui déplace le débat sur les ettains de l'ordre international de l'information et de la communication, des cadres socio-politiques et médiatiques et socio-culturelles, des émissions diffusées peuvent être appréhendées en dépassant les approches classiques, en se focalisant sur la réception et en prenant en compte les mutations de ces dernières années.
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Brochado, Thaís. "Teores de fibra em detergente neutro em dietas de alto concentrado para cordeiros em terminação." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-22022017-084018/.
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Embora dietas de alto concentrado sejam comumente utilizadas para acabamento de cordeiros, informações sobre o efeito de teores mínimos de fibra em detergente neutro (FDN) sobre o desempenho de cordeiros são limitadas. O objetivo deste estudo foi avaliar os efeitos da inclusão de baixos teores de FDN em dieta de alto concentrado sobre desempenho, eficiência alimentar, características de carcaça, variáveis sanguíneas e ruminais de cordeiros em terminação. Vinte e quatro cordeiros machos, não castrados (peso vivo inicial de 24,55 ± 2,2 kg) foram distribuídos aleatoriamente em baias individuais, em delineamento inteiramente casualizado, com três tratamentos e oito repetições. Os tratamentos foram teores de FDN na dieta de 15, 20 e 25% com base na matéria seca. As dietas foram compostas de milho, farelo de soja, minerais e silagem de milho, e foram oferecidas duas vezes por dia, com controle diário do alimento ofertado e sobra para determinação da ingestão de matéria seca (IMS). Os animais foram pesados semanalmente e abatidos após 50 dias de confinamento, com peso vivo final de 40,48 ± 2,3 kg. Peso de carcaça quente e fria (PCQ e PCF), bem como o rendimento de carcaça quente e fria (RCQ e RCF) foram medidos. Após a evisceração, foram coletados fluido e conteúdo ruminal para determinação de ácidos graxos de cadeia curta e protozoários. Os dados foram submetidos à análise de regressão, utilizando o pacote estatístico SAS® (versão 9.0, 2002). Cordeiros alimentados com diferentes teores de FDN, apresentaram efeito linear crescente sobre a IMS e o consumo alimentar residual (CAR) conforme aumentou o teor de FDN na dieta. O ganho médio diário (GMD) e as demais variáveis de eficiência alimentar não diferiram estatisticamente entre os tratamentos. Os teores crescentes de FDN na dieta ocasionou diminuição do PCQ, RCQ e RCF, e não houve efeito significativo sobre as demais variáveis de carcaça. As variáveis sanguíneas e ruminais não foram alteradas pelos tratamentos, sugerindo que as dietas utilizadas com alto teor de concentrado e diferentes teores de FDN para cordeiros em terminação proporcionaram homeostase aos animais e ambiente adequado para fermentação ruminal. De modo geral, as dietas com teores baixos de FDN não alteraram o GMD, mas tiveram efeito sobre CAR, peso e rendimentos de carcaça aumentaram e não proporcionaram alterações fisiológicas e ruminais.Although high concentrate diets are commonly used for finishing lambs, information about the effect of minimum levels of neutral detergent fiber (NDF) on performance is limited. The purpose of this study was to evaluate the effects of increasing dietary fiber levels on performance, feed efficiency and parameters of carcass, blood and rumen of finishing lambs fed high concentrate diet. Twenty four uncastrated male lambs (initial body weight of 24.55 ± 2.2 kg) were randomly assigned to 24 individual pens, in a complete randomized design with three treatments and eight replicates. Treatments were dietary NDF levels of 15, 20 and 25% based on dry matter. Diets were composed of corn, soybean meal, minerals and corn silage, and were offered twice a day with refusals daily measured to determine dry matter intake (DMI). Animals were weighed weekly and slaughtered after 50 d of feedlot, with body weight of 40.48 ± 2.3 kg. Hot and cold carcass weight (HCW and CCW) as well as hot and cold carcass yield (HCY and CCY) were measured. After evisceration, fluid and rumen contents were collected to determine fatty acid short chain and protozoa. Data were submitted to analysis of regression, using the statistical software SAS (version 9.0, 2002). Lambs fed with increasing levels of NDF had a linear efeect on IMS and residual feed intake (RFI). The average daily gain (ADG) and other food efficiency variables were not statistically different between treatments. Increasing levels of NDF in the diet caused a decrease in HCW, HCY and CCY, and there was no significant effect on other carcass variables. Blood and rumen variables were not affected by treatments, suggesting that the diets with high concentrate and different levels of NDF for finishing lambs provided homeostasis animals and adequate environment for rumen fermentation. In general, diets with low NDF did not alter the ADG, but had no effect on RFI, weight and carcass yield increased and did not provide physiological and ruminal changes.
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Peres, Anelise Ribeiro [UNESP]. "Efeitos da dieta e da eficiência alimentar de touros jovens nelore sobre a expressão gênica e acúmulo intracelular de lipídeos em embriões pré-implantacionais produzidos in vitro." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/156023.
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Na bovinocultura de corte, a alimentação corresponde ao maior custo associado à produção de carne. A avaliação do consumo alimentar residual (CAR) tem sido uma ferramenta importante para direcionar a seleção de bovinos de corte e otimizar economicamente esta atividade. No entanto, alguns estudos mostram uma diminuição da motilidade, do perímetro escrotal, uma menor taxa de prenhez e parto em animais eficientes para CAR. Uma estratégia para solucionar tais problemas é a suplementação ácidos graxos poliinsaturados (AGPs) que não apenas aumentam a densidade energética da dieta, mas também atuam na melhoria do desempenho reprodutivo. No entanto, o ideal é que tais características de seleção para CAR e efeito da suplementação com AGPs sejam passadas à prole, assim o objetivo desse trabalho foi avaliar o efeito paterno da seleção para consumo alimentar residual (CAR) e da suplementação dos touros com AGs para a PIVE, o acúmulo de lipídio embrionário e a expressão de genes. Animais classificados em baixo CAR e alto CAR foram utilizados no experimento. O delineamento experimental obedeceu a um esquema fatorial 2 x 2 (CAR x Suplementação), a análise estatística foi realizada pelo programa JPM (versão 5.0.1, SAS Institute). Após a amostragem, os animais foram separados aleatoriamente em dois grupos: com suplementação de AGs protegido e com suplementação controle (sem AGs protegido). O experimento foi composto por quatro tratamentos, o sêmen dos touros foi congelado (4 tratamentos), sendo 6 animais suplementados com AGs protegido (3 baixo CAR e 3 alto CAR) e 6 animais com suplementação controle, sem AGs (3 baixo CAR e 3 alto CAR). O sêmen foi utilizado para produção in vitro de embriões; os blastocistos foram reservados para análise da quantificação de lipídios e os blastocistos expandidos para análise da expressão gênica. A quantificação de lipídios foi avaliada utilizando o corante Sudan Black B 1% e as imagens foram analisadas pelo programa Image J (National Institutes of Health, USA). A análise de expressão gênica dos embriões foi feita pela técnica de qPCR utilizando o sistema de micro-fluídica Biomark HD (Fluidigm®, South San Francisco, CA, USA). Não houve diferença na produção in vitro de embriões oriundos de animais CAR- ou CAR+, nem entre os tratamentos suplementados com AGs. Embriões de touros CAR+ apresentaram maior conteúdo lipídico quando comparado com o grupo CAR-. Os genes que apresentaram diferença associados à dieta foram o HMOX1, SREBF1 e o GPX4. Os referentes ao perfil CAR que diferiram foram o PLAC8, PPARGC1A e o NFE2L2. Os relacionados com a interação entre dieta e CAR que apresentaram diferença foram o RPLP0, ATF4, H3F3A, HSF1, HMGCS1, SLC2A5, NANOG, REST e o GPX4. Conclui-se que a dieta e a seleção para CAR dos touros afetou a expressão gênica dos embriões produzidos in vitro utilizando o sêmen desses animais.
In beef cattle, feed corresponds to the highest cost associated with meat production. The evaluation of the selection for residual feed intake (RFI) has been an important tool to direct the selection of beef cattle and economically optimize this activity. However, some studies show a decrease in motility, scrotal perimeter, a lower pregnancy and calving rate in efficient animals for RFI. One strategy to solve such problems is polyunsaturated fatty acid (PUFA) supplementation that not only increases the energy density of the diet, but also improves reproductive performance. However, the ideal is that these characteristics of selection for RFI and effect of the supplementation with PUFA are passed to offspring, so the aim of this work was to evaluate the paternal effect of selection for residual feed intake and supplementation of bulls with fatty acids for in vitro produced embryos (IVPE), accumulation of embryonic lipid and gene expression. Animals classified under low RFI and high RFI were used in the experiment. The experimental design was based on a 2 x 2 factorial scheme (RFI x Supplementation), the statistical analysis was performed by the JPM program (version 5.0.1, SAS Institute). The animals were randomly divided into two groups: with protected fatty acids supplementation and with control supplementation (without protected fatty acids). The experiment was composed of four treatments, the semen of the bulls was frozen (4 treatments), 6 animals were supplemented with protected fatty acids (3 low RFI and 3 high RFI) and 6 animals with control supplementation, without protected fatty acids (3 low RFI and 3 high RFI). The semen was used for IVPE; blastocysts were reserved for analysis of lipid quantification and expanded blastocysts for analysis of gene expression. The quantification of lipids was evaluated using the Sudan Black B 1% dye and the images were analyzed by program Image J (National Institutes of Health, USA). The gene expression analysis of the embryos was done by the qPCR technique using the Biomark HD microfluidic system (Fluidigm®, South San Francisco, CA, USA). There was no difference in the in vitro production of embryos from RFI- or RFI+ animals, there was also no difference between treatments (supplementation). Embryos from RFI+ bulls presented higher intracytoplasmic lipid content than embryos from RFI- bulls. The genes that showed differences associated with the diet were HMOX1, SREBF1 and GPX4. The RFI associated genes that differed were PLAC8, PPARGC1A and NFE2L2. Those related to the interaction between diet and RFI that presented difference were RPLP0, ATF4, H3F3A, HSF1, HMGCS1, SLC2A5, NANOG, REST and GPX4. In conclusion, the diet and the selection for RFI of the bulls affected the gene expression of the embryos produced in vitro using the semen of these animals.
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Lillrose, Micah Alexander. "High-Speed Data Acquisition and FPGA Detected Pulse Blanking System for Interference Mitigation in Radio Astronomy." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1177.
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Radio astronomy is the discipline dedicated to the study of celestial emissions in the radio band from a few MHz to 300 GHz. In recent years, spurious emissions from man-made devices that operate at these frequencies have made detection of astronomical signals difficult. These harmful RF transmissions are called radio frequency interference (RFI). One strategy to remove RFI is to apply spatial filtering using an array antenna. This thesis documents the development of a high-speed data acquisition system used to record data from 7- and 19-element phased array feeds. The system supports synchronous sampling over all channels and streams data to disk allowing spatial filtering to be applied in post-processing. The development of a time blanking RFI mitigation system was also developed as part of this thesis. Time blanking is a strategy to remove radar interference by blanking the time intervals corrupted by radar transmissions. The two blanking strategies are time window blanking and detected pulse blanking. This thesis documents the design and implementation of a detected pulse blanking system built using FPGAs. The system employs complex signal processing techniques to detect and excise radar transmissions in real time. This FPGA RFI mitigation system is the first to use a matched filter in pulse detection. Successful radio frequency interference mitigation is demonstrated by removing simulated radar interference from a sinusoidal tone.
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Lambert, Michael J. "Radio Frequency Interference Cancellation,Appraisal, Detection, and Correction." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7394.
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Radio Astronomy, the study of distant objects in the radio spectrum, is set at defiance against all other users of the electromagnetic spectrum. Where traditional use would fill the electromagnetic spectrum with as much transmission and information as possible, Radio Astronomy would rather no man-made signals existed. Since that is not possible, they grumble and have to deal with unwanted transmissions impinging upon their instruments. I have demonstrated that subspace projection can remove these unwanted signals from Radio Astronomical data in post processing. I demonstrate it both on simulated data and on data taken from the Very Large Array radio telescope.In the process of implementing the algorithm, I show that the self power terms contain necessary information about the array element responses to RFI sources. While the autocorrelation are not used in the normal synthesis imaging process, my work shows that RFI mitigation using Subspace Projection performs better with the autocorrelations retained when computing projection matrices. Furthermore, I demonstrate that proper data collection allows a significant decrease in error under subspace projection. Potential enhancements to subspace projection are also briefly considered.
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Wagner, Jan Florian [Verfasser], Andreas [Akademischer Betreuer] Eckart, and J. Anton [Akademischer Betreuer] Zensus. "RFI Mitigation for VLBI and Arrays - Water Megamasers in Active Galaxies / Jan Florian Wagner. Gutachter: Andreas Eckart ; J. Anton Zensus." Köln : Universitäts- und Stadtbibliothek Köln, 2014. http://d-nb.info/105442036X/34.
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Katembera, Serge Rhukuzage. "Novas mídias e empoderamento na áfrica francófona: O caso de uma plataforma de blogueiros – Mondoblog do Atelier des Médias/RFI." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/9742.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Ce travail est consacré à l'analyse des dynamiques observées sur une plateforme de blogueurs, Mondoblog, créée par l’Atelier des Médias, une émission de la station de radio RFI, en se concentrant principalement sur les différentes dimensions des rapports entre ces blogueurs et les responsables de ladite plateforme. Des concepts tels que l'autonomie (GILROY, 2001 et 2011), l'empowerment (CALVÈS, 2009), la visibilité et la construction d'un sphère publique numérique en Afrique francophone sont examinés à la lumière des réalités vécues par les blogueurs que nous avons interviewés in situ et/ou au moyen d'un questionnaire appliqué en ligne. Une discussion méthodologique est faite au tout début de ce travail révélant les difficultés que nous avions à traiter de façon critique un sujet que nous connaissions de l’intérieur (MAGNANI, 2002). Il était donc nécessaire de prendre une certaine distance para rapport à ce champ de recherche; et, paradoxalement, de capitaliser sur la connaissance profonde de celuici. Le travail recherche un equilibre entre le discours optimiste sur les Nouvelles Technologies et le discours pessimiste montrant par des exemples concrets que les deux positions sont justifiables. C’est principalement grâce aux interventions des blogueurs eux-mêmes, la façon dont ils construisent une image de soi, que nous avons eu accès à l'impact de ces Nouvelles Technologies dans leurs vies. Nous nous sommes intéressés par l'histoire de leurs vies, par leurs aspirations et leurs frustrations dans leurs rapports à la plateforme. Nous avons discuté de leur impact sur la société nous référant essentiellement à la Théorie de l’agenda développée dans le domaine de la communication par Maxwell McCombs (2009). Enfin, nous montrons qu’avec l'émergence de Nouvelles Technologies et de leur expansion sur le continent africain, le marché du journalisme français, aujourd'hui en crise, trouve dans le continent africain de nombreuses opportunités dans sa capacité à recruter des “correspondants” – avec un statut de blogueur – à un coût réduit. Le mérite de ce travail est de montrer que dans le contexte de la mondialisation ces deux marchés sont intégrés de telle sorte que cette nouvelle configuration sociologique exige d’autres analyses plus approfondies de ce type.
Este trabalho se dedica à análise das dinâmicas de uma plataforma de blogueiros, Mondoblog, criada pelo programa Atelier des Médias da emissora Radio France Internationale, focalizando-se essencialmente nas diversas dimensões das relações entre os blogueiros e os responsáveis da dita plataforma. Conceitos como autonomia (GILROY, 2001 e 2011), empoderamento (CALVÈS, 2009), visibilidade e construção de uma esfera pública digital na África francófona são examinados à luz da realidade dos blogueiros que entrevistamos presencialmente e mediante um questionário aplicado online. Uma discussão metodológica inicia o trabalho revelando as dificuldades que tivemos de abordar criticamente um tema que conhecemos de dentro (MAGNANI, 2002), sendo, paradoxalmente, necessário tomar uma distância em relação a esse campo de pesquisa; bem como capitalizar nesse conhecimento profundo do mesmo. O trabalho busca um equilíbrio entre o discurso otimista relativo às Novas Tecnologias e o discurso pessimistas mostrando com exemplos concretos que ambas as posições são justificáveis. É sobretudo, graças às falas dos próprios blogueiros, a forma como constroem sua autoimagem, que temos acesso ao impacto das Novas Tecnologias na vida dessas pessoas. Nos interessamos em suas trajetórias de vida, suas aspirações e frustrações atuando na plataforma. Discutimos seu impacto na sociedade através do tema do agendamento desenvolvido na área da comunicação por Maxwell McCombs (2009). Por fim, mostramos que com a emergência das Novas Tecnologias e sua expansão no continente africano, o mercado do jornalismo francês hoje em crise encontra no continente africano amplas oportunidades na sua capacidade de recrutar “correspondentes” – com status de blogueiros – a um custo reduzido. O mérito deste trabalho é mostrar que, num mundo globalizado, esses dois mercados estão integrados de tal modo que essa nova configuração sociológica necessita mais análises deste tipo.
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Lorandi, Natália Pagnoncelli. "Estudo das propriedades dinâmico-mecânicas e fluência de compósitos epóxi/tecido não-dobrável de carbono produzidos por VARTM e RFI." reponame:Repositório Institucional da UCS, 2016. https://repositorio.ucs.br/handle/11338/1844.
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A excelente relação custo-peso-desempenho de compósitos poliméricos em relação aos materiais tradicionais tornou-se motivo para o desenvolvimento de materiais avançados para aplicação estrutural, como compósitos epóxi/fibra de carbono, e com isso, novos métodos de processamento, diferentes resinas (matriz) e tecidos de fibras (reforço). Polímeros e seus compósitos apresentam comportamento viscoelástico, e fatores como estabilidade dimensional e resistência mecânica a longo prazo devem ser considerados quando utilizados na indústria aeronáutica. A análise dinâmico-mecânica (DMA) permite a avaliação das propriedades viscoelásticas do material, e ensaios de fluência possibilitam o estudo da deformação do material em função do tempo, sob tensão e temperatura constantes. Neste trabalho, compósitos epóxi/tecido não-dobrável (NCF) de carbono foram produzidos utilizando-se duas técnicas de fabricação: moldagem por transferência de resina com vácuo assistido (VARTM) e infusão de resina em filme (RFI), e uma análise comparativa entre os dois compósitos foi realizada. O módulo de armazenamento, E’, do compósito RFI foi aproximadamente 10 GPa maior ao longo da região vítrea e a Tonset aproximadamente 60°C mais alta em relação ao VARTM. O compósito RFI também apresentou uma região de transição vítrea mais larga (a partir da curva de tan δ). Esses resultados foram associados às relaxações moleculares e maior cooperatividade das cadeias, assim como maior rigidez do compósito RFI. Os ensaios de fluência foram realizados em três diferentes tensões e temperaturas, e o compósito VARTM apresentou maior deformação em função do tempo, indicando uma interface fibra/matriz mais fraca e um compósito menos rígido, e corroborando com os resultados de resistência ao cisalhamento interlaminar, a qual foi maior para o compósito RFI. Os modelos de Findley e de Burger foram aplicados e ambos ajustaram-se bem às curvas experimentais de fluência. Os parâmetros de cada modelo foram associados ao comportamento viscoelástico dos compósitos e relacionados com os demais resultados.Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-03-16T17:48:39Z No. of bitstreams: 1 Dissertacao Natalia Pagnoncelli Lorandi.pdf: 2042542 bytes, checksum: a231d9dd1acdbee5c47b2794a5af07be (MD5)
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The excellent cost-weigh-performance relationship of polymeric composites compared to traditional materials became a reason to development of advanced materials for structural application such as carbon/epoxy composites, and with that, new processing methods, different resins (matrix) and fabrics (reinforcement) producing. Polymers and their composites present viscoelastic behavior, and so issues such as dimensional stability and long-term resistance must be taken into account when used by aeronautic industry. Dynamic-mechanical analysis (DMA) allows the evaluation of viscoelastic properties, and with creep tests, it is possible to study materials strain as function of time, under constant stress and temperature. In this study, epoxy/carbon NCF composites were manufactured by two techniques: vacuum assisted resin transfer molding (VARTM) and resin film infusion (RFI), and a comparative analysis between both composites was made. Storage modulus, E’, for RFI composite was approximately 10 GPa higher along the glassy region and Tonset approximately 60°C higher than VARTM composite. RFI composite also presented a wider glass transition region (form tan δ curve). These results were associated to the molecular relaxation and higher chain cooperative motion, and to the higher stiffness of RFI composite. Creep strain tests were performed in three different stress levels and temperatures, and VARTM composite presented larger creep strain with time, indicating a weaker interface fiber/matrix and a lower stiffness composite, and corroborating with short-beam shear resistance. Findley and Burger’s model were applied and both agreed well with experimental creep curves. Parameters of each model were associated to composites viscoelastic behavior and they were related to the other results.
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Dupoux, Céline. "Méthode d'analyse en vue de l'amélioration des interférences électromagnétiques dans les systèmes intégrés radio fréquence." Thesis, Toulouse, INSA, 2011. http://www.theses.fr/2011ISAT0027/document.
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Les travaux présentés dans ce mémoire proposent une méthodologie d'étude des interférences électromagnétiques dans les systèmes intégrés RF. Cette thèse se focalise sur les problèmes de couplage rayonné en champ proche entre différentes parties d'une puce électronique ou entre circuits intégrés d'une carte.Ensuite cette méthodologie est appliquée sur deux cas d'études à différentes échelles, dans le premier cas l'étude du couplage entre un amplificateur de puissance 3G et un transceiver est présentée puis un modèle de couplage est réalisé reproduisant les effets parasites observés lors des mesures. Puis une étude pour extraire et évaluer les couplages entre blocs, ici inductance d'un VCO et structures proches, d'une puce électronique. Ensuite un modèle d'émission champ proche de ce circuit est proposé.Ces travaux mettent en évidence l'intérêt de réaliser des études CEM à chaque phase de conception d'un circuit ou d'un système ainsi que l'intérêt des mesures champ proche qui permettent de réaliser de l'investigation et du diagnostic CEMThe work presented in this PhD suggest a methodology for the study of electromagnetic interference in RF integrated systems. This thesis focuses on the problems of near-field radiated coupling between different parts of a chip or between ICs.Then this methodology is applied to two case studies on different scales, in the first case study the coupling between a 3G power amplifier and a transceiver is presented then a model of the coupling is made reproducing parasitic effects observed in measurements. Then a study to extract and evaluate the coupling between blocks, between a VCO inductor and nearby structures of a microchip. Then a near-field emission model of this circuit is proposed.These works demonstrate the interest of EMC studies in all phases of designing a circuit or system and the interest of near-field measurements that allow the realization of the investigation and diagnosis of EMC
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Nybo, Jeffrey M. "Development of a GPU-Based Real-Time Interference Mitigating Beamformer for Radio Astronomy." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7749.
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Radio frequency interference (RFI) mitigation enables radio astronomical observation in frequency bands that are shared with many modern satellite and ground based devices by filtering out the interference in corrupted bands. The present work documents the development of a beamformer (spatial filter) equipped with RFI mitigation capabilities. The beamformer is intended for systems with antenna arrays designed for large bandwidths. Because array data post processing on large bandwidths would require massive memory space beyond feasible limits, there is a need for a RFI mitigation system capable of doing processing on the data as it arrives in real-time; storing only a data reduced result into long term memory. The real-time system is designed to be implemented on both the FLAG phased array feed (PAF) on the Green Bank telescope in West Virginia, as well as future radio astronomy projects. It will also serve as the anti-jamming component in communications applications developed for the United States office of naval research (ONR). Implemented on a graphical processing unit (GPU), this beamformer demonstrates a working single step filter using nVidia's CUDA technology, technology with high-speed parallelism that makes real-time RFI mitigation possible.
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Kinley, John Dirk 1971. "RFID ROI." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28511.
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Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2004.Includes bibliographical references (leaves 46-47).
This thesis investigates financial results from RFID integration at product level in semiconductor manufacturing. The thesis explores how the technology might act in concert with other significant logistics tools to create return on investment. In this case, the use of RFID, along with postponement and Kanban practices, may help a manufacturer better align supply with central processing unit (CPU) demand. The resulting economic benefits are explored through yield scenarios. It is important to note that the thesis explores this topic without the benefit of empirical data. Consequently, a number of assumptions were made; these assumptions may affect the validity of the observations. Nonetheless, the study demonstrates an innovative approach that may contribute to new models of creative problem solving.
by John Dirk Kinley.
M.Eng.in Logistics
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Andrews, Mark Joseph. "Design Considerations for 500-2000 MHz Ultra-Wideband Radiometric Measurements." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1618312655065238.
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Demonget, Ariane. "Les stations de radiodiffusion internationale et la question européenne : analyses autour de BBC World Service, e la Deutsche Welle Radio et de RFI." Bordeaux 3, 2010. http://www.theses.fr/2010BOR30048.
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La fin de la Guerre froide engendre une remise en question de la radiodiffusion internationale, dont la fonction de « substitution » n'est plus légitimée. Ce bouleversement mondial permet aussi une accélération de la construction européenne. Les stations de radiodiffusion internationale BBC World Service (BBCWS), Deutsche Welle Radio (DWR) et Radio France Internationale (RFI) se trouvent à la fois dans l'obligation et dans la nécessité de traiter de l'Europe, que le « tournant », rend politiquement réalisable. En effet, ces stations, qui représentent trois pays piliers de l'Union européenne, et qui sont mues par une vocation internationale, devraient être un vecteur prioritaire de l’opinion publique européenne. En fait, ces trois stations traitent bien de l'Europe, mais des divergences se font jour d'une station à l'autre. Tout d'abord, les émissions dédiées à l'Europe sont souvent liées à des subventions proposées par l'Union européenne, afin que le sujet « Europe » soit plus présent dans les médias et que les citoyens européens s'y familiarisent. Ensuite, RFI et la DWR créent, et parfois, pérennisent des émissions de partenariat et produisent aussi des émissions propres à leur station, avec l'aide des subventions européennes. À contrario, le BBCWS évite les partenariats et les subventions, et l'unique émission consacrée à l'Europe perdure sur toute la période analysée (2004-2009). Enfin, la DWR manifeste un engouement particulier pour le sujet européen, en lui dédiant des émissions nombreuses, variées, mais aussi, souvent éphémères. Aussi, ces trois stations n'apparaissent pas nécessairement comme des vecteurs prioritaires de l’opinion publique européenneThe end of the Cold war generates a challenge to international broadcasters, since the purpose of “substitution” is no longer legitimate. This world upheaval allows also an acceleration of european integration. The international broadcasters BBC World Service (BBCWS), Deutsche Welle Radio (DWR) and Radio France Internationale (RFI) need and at the same time have no other option than to deal with the European issue, now made politically feasible by the “turning point”. These three stations driven by an international scope and representing mainstays of the European Union should in fact be a primary vehicle for the European public opinion. As a matter of fact, the three stations indeed deal with the European issue but differences emerge from one station to another. First, radio broadcasts dedicated to Europe are often linked to grants offered by the European Union for the european issue to be more prevalent in the media and for the citizens to become familiar with it. Then, RFI and DWR create and sometimes perpetuate joint radio broadcasts as well as produce some other broadcasts for their very own stations often with the help of the European grants. The BBCWS on the other hand avoids partnerships and grants and the only broadcast devoted to Europe lasts throughtout the era analyzed here (2004-2009). At last, the DWR shows an evident enthusiasm for the topic of “Europe” dedicating numerous and varied but often short-lived broadcasts. Also, these three stations do not necessarily seem to be primary vehicles for the European public opinion
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Jul, Lene. "Adding Values, Upholstery Concepts for Automotives Using Smart Textiles." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-18540.
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New textile materials are constantly being brought into the automotive field, and automobile design is a leader in innovative and spectacular developments where smart textile materials are used. The main elements of the current project are textile material research, automotive research, design and development of two upholstery concepts for automotives using smart textiles. The added values are RFI/EMI (Radio Frequency Interference / Electro Magnetic Interference) shielding qualities, light emitting, light reflective and antistatic qualities. Values in the smart-textile area are obtained through choice of material and textile techniques. Transportation textiles are considered high performance technical fabrics, but they must also meet the aesthetic demands of the market. In the current project the design is inspired by Japanese architectural thinking and strives to relate to outdoor environment to reduce the border between indoor and outdoor environment. The inspiration source is water surfaces. The colour setting is also inspired by water surfaces. Material selection is based on the chosen added values, material qualities, appearance and availability. The result of the work is two different upholstery concepts visualizing qualities of smart materials and requests the automotive field. Sprinkle is an upholstery with light emitting, light reflective and antistatic values. The materials used are monofilament, polyester and electroluminescent wires. Wave is an upholstery design with antistatic, light reflective and RFI/Emi shielding qualities. The materials used are stainless steel yarn, rubco and monofilament.Program: Konstnärligt masterprogram i mode- och textildesign
Uppsatsnivå: D
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Wiid, P. Gideon. "Lightning protection and radio frequency interference mitigation for the Karoo Array Telescope." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4009.
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Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: South Africa and Australia are now the two remaining countries bidding for the Square Kilometre Array (SKA), the biggest and most sensitive project ever undertaken in radio astronomy. The South African SKA is demonstrating its technology capabilities through the Karoo Array Telescope (KAT or MeerKAT). The development of KAT is taking place in stages to optimise design and minimise risks at each stage. An array of seven 12 m antennas will be complete by the end of 2009, called KAT-7. The following phase will see the construction of MeerKAT, which will lead to eighty arrayed dishes. Lightning and RFI studies for KAT-7 are the focus of this dissertation. Due to the extent and complexity of the South African demonstrator project, these studies have largely been conducted on a single structure. Parameters for the dish antenna and pedestal design changed throughout their development. To be effective, the doctoral research had to track these changes appropriately. A Method of Moments frequency domain computational electromagnetic code, FEKO, is used throughout the study. The consequences of direct and indirect lightning strikes are examined for the KAT-7 structure. Important FEKO model verification is achieved through measurement of physical scale models in an anechoic chamber. The microwave simulation code, CST, gives direct comparison of FEKO results by using a finite volume time domain method of calculation. Using frequency domain analysis on these models, the lightning down conductor design over the dish antenna bearings is optimised with cost-effectiveness as one driving parameter. RFI coupling levels for different designs are compared to each other to identify areas requiring RFI mitigation. Analysis of resonances enables evaluation of the mitigation at frequencies sensitive to radio astronomy. A Sommerfeld integral ground plane is used together with the computational model to investigate the use of the concrete foundation steel reinforcing as part of the lightning earthing electrode system. Different interconnections of the steel reinforcing elements are critically evaluated. The KAT-7 design incorporated clear lightning protection and RFI mitigation policies derived from recommendations contained within this dissertation.
AFRIKAANSE OPSOMMING: Suid-Afrika en Australie is nou die oorblywende twee lande wat bie vir die Vierkante Kilometer Reeks (SKA), die grootste en mees sensitiewe projek nog ooit in radio astronomie onderneem. Die Suid Afrikaanse SKA demonstreer sy tegnologiese bekwaamheid met die Karoo Reeks Teleskoop (KAT of MeerKAT). Die ontwikkeling van KAT vind plaas in fases om die ontwerp te optimaliseer en risikos te minimaliseer met elke fase. ’n Reeks van sewe 12 m antennas, genaamd KAT-7, sal teen die einde van 2009 klaar wees. Die volgende fase behels die konstruksie van MeerKAT, wat sal lei tot ’n tagtig-skottel reeks. Die fokus van hierdie proefskrif hanteer weerlig en radiofrekwensie steurings (RFS) vir KAT-7. As gevolg van die omvang en kompleksiteit van die Suid-Afrikaanse demonstreerder projek, is die studies hoofsaaklik op een struktuur gedoen. Parameters vir die antenna-skottel en -voetstuk ontwerp het met hul ontwikkeling deurgaans verander. Om effektief te wees, moes die doktorale navorsing hierdie veranderinge toepaslik volg. ’n Metode-van-Momente frekwensiedomein rekenaar elektromagnetiese kode, FEKO, is deurgaans met die studie gebruik. Die gevolge van direkte en indirekte weerligslae vir die KAT-7 struktuur is ondersoek. Belangrike FEKO model bevestiging is bereik met metings van skaalmodelle in ’n anego¨ıse kamer. Die mikrogolf-simulasie kode, CST, gee ’n direkte vergelyking met die FEKO resultate deur ’n eindige-volume-tyd-domein metode van berekening te gebruik. Met behulp van frekwensiedomein analise van hierdie modelle, is die weerligafleierontwerp oor die antenna-skottel laers ge-optimaliseer, met koste-effektiwiteit as een van die drywingsparameters. RFS koppelingsvlakke vir onderskeie ontwerpe is teen mekaar opgeweeg om areas te identifiseer wat RFS tempering benodig. Analise van resonansies stel die evaluering van die tempering in staat teen frekwensies wat sensitief is vir radio astronomie. ’n Sommerfeld integrale grondvlak word saam met die rekenaarmodel gebruik om die insluiting van die beton se staalversterking as deel van die aardingselektrodestelsel te ondersoek. Verskillende bindmetodes van die onderlinge staalversterkingselemente word krities ge¨evalueer. Die KAT-7 ontwerp inkorporeer duidelike weerligbeveiligings- en RFS temperingstrategie ¨e, komende van aanbevelings in hierdie proefskrif omskryf
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Banks, Paul Russell. "Characterisation of the radio noise environment in New Zealand." Click here to access this resource online, 2009. http://hdl.handle.net/10292/787.
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A methodology for the measurement of the radio frequency environment close to the radio noise floor is presented for urban, suburban and rural areas within New Zealand for the purposes of characterisation and trend monitoring by radio spectrum managers. Flux density measurements in bands within a range of frequencies from 80 MHz to 8 GHz have been made in urban, suburban and rural areas of New Zealand during 2007 and 2008. An analysis of the band occupancy is presented in summary form. These summaries are intended as a starting point for radio spectrum usage and can be used as a reference for any future measurements. A description of the computer directories and charts resulting from these measurements, using 20 MHz bandwidths have also been included. All the results for the work have been collated in a set of computer directories named “NZRFI Directories 2007 2008”, which are intended as a reference for use in the determination of local activity in particular frequency ranges. A disc with the full range measurement spectral density charts and channel occupancy charts accompanies this work. Also included on the disc are sets of 20 MHz band charts for some urban, suburban and rural location measurements.
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Guilford, Shane, and Mark C. Kutis. "RFID benefits: looking beyond ROI." Monterey, California. Naval Postgraduate School, 2005. http://hdl.handle.net/10945/9979.
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MBA Professional ReportWe explore whether benefits are being realized in RFID initiatives that are not being captured by traditional Return on Investment analysis. Utilizing the Naval Supply System Report, which found RFID technology does not create a positive ROI, we surveyed the participants to find benefits they received that were not addressed. 100% of the participants reported increased customer knowledge and increased timeliness of information. While this finding may not be enough to support the implementation of new technologies, it at least supports the idea that the new technologies do have real benefits. This report is therefore intended as a tool to be used by the Navy in addressing the idea that traditional ROI does not capture these intangible benefits. We acknowledge the fact that further study of this important issue is needed.
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Canales, Sebastian Nerea. "Full-wave analysis and design of a realistic rail-track circuit based on loosely-coupled inductive loops." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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This Master Thesis approaches the analysis and design of a novel solution for the “Circuito di binario (CdB”) i.e., a railway track circuit, that is used as a detection system of the trains for track management and is integrated into the signalling and safety systems on board. The presented CdB exploits an inductive loop system coupled to an S-shaped joint (replacing the previously used mechanical joints) in the audio-frequency range (from 8 to 16 kHz). The tracks, therefore, constitute a transmission route similar to a transmission line equipped with a Transmitter (Tx) and a Receiver (Rx), and can be used to transmit information.
As a starting point, different electromagnetic simulations of a prototype system of the CdB (scale 1:4), realized in the ARCES laboratories of the University of Bologna, have been carried out. A 3D replica of the CdB has been realized in CST and electromagnetically analysed. Afterward, the Rail Trak with its actual dimension (scale 1:1) has been simulated and the length of the S joint has been optimized in such a way that that the loops that are not in the Tx-Rx circuit are highly decoupled, whereas the coupling of those that are part of the communication circuit is maximum. Subsequently, with the purpose to lighten the whole CdB electromagnetic simulations, the rail-track has been analysed alone in order to extract an equivalent circuit to be used in AWR together with the outputs (scattering matrices) of the electromagnetic simulations of the S joint with loop (both Tx and Rx).
The agile obtained optimization tool has allowed the design of the two matching networks with lumped components (one between the transmitting circuit and the Tx loop, the other between the Rx loop and the receiving circuit) for the maximization of the received power: the highest challenge of this project has been the satisfaction of the matching over such a broad frequency band (equal to one octave).
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Imani, Shabnam, and Elnaz Farzaneh. "Electromagnetic Compatibility Requirements for Medical Device Certification." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-13705.
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Until approximately 50 years ago, wireless electronics was confined to military purposes. With the advancement of technology, consumer electronics found widespread applications in almost every aspect of our lives and numerous devices were developed using electromagnetic waves to transfer different types of data. In light of such advancements, the electromagnetic compatibility (EMC) evolved from a military concept to regulate the radio frequency requirements of the battlefield equipment to a mature and essential part in manufacturing and employing electronic devices. Medical devices were no exception and largely benefited from the ease of connectivity and mobility provided by usage of wireless electronics. Due to the sensitive nature of medical devices and extreme consequences of their malfunction, EMC grew to a centric issue in design and production of such devices. This work examines the electromagnetic compatibility of a wearable biomedical measurement system used for the assessment of mental stress of combatants in real time. This system was developed as a part of the ARTEC project and supported by the Spanish Ministry of Defense through the Future Combatant program [1]. We focus on the EMC of the electrocardiogram of the system and aim to identify its EMC requirements of this system while assessing it against various standards and protocols. Throughout this study, we elucidate the fundamentals of electromagnetic compatibility with specific attention to medical devices. Furthermore, we present our results after conducting several EMC tests to measure the compatibility of the electrocardiogram device using the Intertek guidelines. The emission test was performed while essential counter measures such as appropriate shielding and anti-interference filters had been applied.
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Čermák, Josef. "Modelování rušení pro xDSL." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217281.
Full textAbstract:
This work is focused on the subject of the interference modelling for xDSL technologies. First, the xDSL technologies are explained. Following is the presentation and description of the different kinds of the xDSL technologies. The next part deals with the basic parameters of metallic cable lines – especially the primary and secondary parameters. Nowadays wider bandwidths are used for the achievement of higher data transmission rates. During a higher frequency signal transmission a more intensive line attenuation appears. To identify the transfer characteristics of the lines while using an xDSL system, mathematic models of transmission lines are applied. That is why these mathematic models are dealt with in the next chapter. At the end of this section the mathematic models are compared using the modular and phase characteristics. The main aim of the work is to describe the different impacts which influence the efficiency of the xDSL systems. First, the causes interfering from the inside of the cable are deeply explained: Near End Crosstalk (NEXT), Far End Crosstalk (FEXT), Additive White Gaussian Noise (AWGN). Following is the explanation of the external interfering impacts: Radio Frequency Interference (RFI) and Impulse Noise. The next goal of this thesis is a design of a workstation for the tests of spectral features and the efficiency of the xDSL systems. The work also presents a designed GUI application and its description. The GUI application is an instrument for the choice or data entry of the final interference. The last chapter describes a realization of a measurement and shows the measured characteristics which were recorded on the ADSL tester and oscilloscope.
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Novotný, František. "Analýza a modelování přeslechů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220322.
Full textAbstract:
The thesis concerns the problem of interference modelling for xDSL technologies and Ethernet. The introduction describes the origin of crosstalk, that arise during the operation of the systems and the physical properties of the lines, therefore, the next section describes the properties of the primary and secondary parameters of the homogenous line and their modelling. In order to achieve higher data rates on the metallic line, systems with larger frequency spectrum are applied, resulting in a greater attenuation of the line. This issue and the characteristics determination of the transmission systems are subjects of the mathematical models, which are divided according to the modelling of primary or secondary parameters. The main goal of this work is to describe the effects which influence the performance of data transfer via xDSL and Ethernet technology focusing on internal and external disturbances acting on the cable lines. This is the crosstalk at the near and far end, adaptive white noise, radio frequency interference RFI and impulse noise. Following part of the thesis deals with the properties of xDSL technologies, specifically ADSL2+ and VDSL2 and Ethernet. Another aim is to design applications which enable to test the performance of xDSL and Ethernet transmission systems with its own award simulations interference. The conclusion describes the design and implementation of laboratory experiments for measuring of the efficiency and spectral properties of xDSL. The proposed laboratory protocols are annexed to this thesis, including the measured waveforms.