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Breimyer, Paul. "The Fast Fourier Transform in the MPEG encoding algorithm." Diss., Connect to the thesis, 2001. http://hdl.handle.net/10066/1488.
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BURCICA, CRISTINA IRINA. "MAPPING THERMAL GRADIENTS IN SCN USING A FAST FOURIER TRANSFORM ANALYSIS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1053544547.
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Garyfalou, Aikaterini. "Integrated analysis of mass transport deposits : outcrop data, seismic interpretation & fast Fourier transform analysis." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227755.
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Milar, Kendall. "Fast Fourier transform analysis of oboes, oboe reeds and oboists : what matters most to timbre." South Hadley, Mass. : [s.n.], 2008. http://ada.mtholyoke.edu/setr/websrc/pdfs/www/2008/257.pdf.
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Li, Hui 1970. "Analysis of edible oils by Fourier transform near-infrared spectroscopy." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36819.
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Fourier transform near-infrared (FT-NIR) spectroscopy was investigated as a means of quantitative analysis of edible fats and oils. Initially, a method of simultaneously determining the cis and trans content, iodine value and saponification number of neat fats and oils using a heated transmission flow cell was developed. Two partial least squares (PLS) calibrations were devised, a process-specific calibration based on hydrogenated soybean oil and a more generalized calibration based on many oil types, the latter able to analyze oils from a variety of sources accurately and reproducibly. Methodology for the quantitative determination of the peroxide value (PV) of edible oils using a novel glass-vial sample handling system was subsequently developed, based on the stoichiometric reaction of triphenylphosphine with hydroperoxides to form triphenylphosphine oxide. The PV calibration was derived using PLS regression, and the results of a validation study demonstrated that PV could be quantitated accurately if a normalization routine was used to compensate for the inherent dimensional variability of the vials. The vial sample handling system was then used in the development of PLS IV calibrations for the process analysis of commercial oil samples, and these samples were also used to evaluate a global IV calibration devised by Bomem Inc. The discriminant features available through PLS were shown to enhance the accuracy of the IV predictions by facilitating the selection of the most appropriate calibrations based on the spectral characteristics of closely related oils. The predictions obtained using the global IV calibration provided clear evidence that a generalized calibration based on a large and varied selection of oils could provide a means of IV determination by FT-NIR spectroscopy. Subsequently, a generalized FT-NIR trans calibration was developed and shown to yield trans values that were in good agreement with those obtained by the AOCS mid-FTIR single-bounce hori
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Rosenthal, Glenn, and Thomas Salley. "USING THE FFT FOR DSP SPECTRUM ANALYSIS: A TELEMETRY ENGINEERING APPROACH." International Foundation for Telemetering, 1990. http://hdl.handle.net/10150/613797.
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International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, NevadaThe Fast Fourier Transform (FFT) converts digitally sampled time domain data into the frequency domain. This paper will provide an advanced introduction for the telemetry engineer to basic FFT theory and then present and explain the different user preprocessing options that are available when using the FFT. These options include: using windowing functions, “zero filling” for frequency data interpolation, and setting the frequency resolution of the FFT resultant spectrum,
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Memon, Khalida Perveen. "Solid fat index determination by Fourier transform (FTIR) spectroscopy." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24028.
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This work describes an investigation of the development of a Fourier Transform Infrared (FTIR) spectroscopic method for the determination of Solid Fat Index (SFI) of fats as a possible replacement of the traditional dilatometric procedure. The initial approach considered was the use of an existing FTIR analytical package which was designed to measure iodine value (IV), saponification number (SN), and cis and trans content. It was hypothesized that these measures could be related to SFI using multiple linear regression (MLR), thereby allowing the existing analytical package to simultaneously make SFI measures. It was found that there was a strong relationship between SN/cis/trans measurements and SFI, especially in sequentially hydrogenated oils. The MLR relationships, however, did not reproduce the dilatometric SFI values with sufficient accuracy in the general case, and this approach had to be abandoned. Subsequently, a partial least squares (PLS) calibration approach was investigated, relating the dilatometric SFI data directly to the spectral characteristics of the melted fats. It was found that suitable PLS calibrations could be developed for soybean and Canola oils. Based on these results, an FTIR system was programmed to determine SFI and the performance of the system validated using pre-analyzed "unknowns". It was shown that the SFI of either soybean or Canola oils could be determined to within $ pm$ 1.0 SFI. As configured, the FTIR system is capable of determining the SFI of a neat and clear, melted fat sample at 80$ sp circ$C in less than two minutes, providing four SFI values, representing the solids content at 50, 70, 80 and 92$ sp circ$F. In contrast to the standard dilatometric method, which takes over two hours to carry out, the FTIR approach provides a rapid means of determining SFI, the technique being suitable for routine quality control applications in the fats and oils industry.
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Pippig, Michael. "Massively Parallel, Fast Fourier Transforms and Particle-Mesh Methods." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-197359.
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The present thesis provides a modularized view on the structure of fast numerical methods for computing Coulomb interactions between charged particles in three-dimensional space. Thereby, the common structure is given in terms of three self-contained algorithmic frameworks that are built on top of each other, namely fast Fourier transform (FFT), nonequispaced fast Fourier transform (NFFT) and NFFT based particle-mesh methods (P²NFFT). For each of these frameworks algorithmic enhancement and parallel implementations are presented with special emphasis on scalability up to hundreds of thousands of parallel processes. In the context of FFT massively parallel algorithms are composed from hardware adaptive low level modules provided by the FFTW software library. The new algorithmic NFFT concepts include pruned NFFT, interlacing, analytic differentiation, and optimized deconvolution in Fourier space with respect to a mean square aliasing error. Enabled by these generalized concepts it is shown that NFFT provides a unified access to particle-mesh methods. Especially, mixed-periodic boundary conditions are handled in a consistent way and interlacing can be incorporated more efficiently. Heuristic approaches for parameter tuning are presented on the basis of thorough error estimatesDie vorliegende Dissertation beschreibt einen modularisierten Blick auf die Struktur schneller numerischer Methoden für die Berechnung der Coulomb-Wechselwirkungen zwischen Ladungen im dreidimensionalen Raum. Die gemeinsame Struktur ist geprägt durch drei selbstständige und auf einander aufbauenden Algorithmen, nämlich der schnellen Fourier-Transformation (FFT), der nicht äquidistanten schnellen Fourier-Transformation (NFFT) und der NFFT-basierten Teilchen-Gitter-Methode (P²NFFT). Für jeden dieser Algorithmen werden Verbesserungen und parallele Implementierungen vorgestellt mit besonderem Augenmerk auf massiv paralleler Skalierbarkeit. Im Kontext der FFT werden parallele Algorithmen aus den Hardware adaptiven Modulen der FFTW Softwarebibliothek zusammengesetzt. Die neuen NFFT-Konzepte beinhalten abgeschnittene NFFT, Versatz, analytische Differentiation und optimierte Entfaltung im Fourier-Raum bezüglich des mittleren quadratischen Aliasfehlers. Mit Hilfe dieser Verallgemeinerungen bietet die NFFT einen vereinheitlichten Zugang zu Teilchen-Gitter-Methoden. Insbesondere gemischt periodische Randbedingungen werden einheitlich behandelt und Versatz wird effizienter umgesetzt. Heuristiken für die Parameterwahl werden auf Basis sorgfältiger Fehlerabschätzungen angegeben
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Heiskanen, Andreas, and Erik Johansson. "Analysing Memory Performance when computing DFTs using FFTW." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230225.
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Discrete Fourier Transforms (DFTs) are used in a wide variety of dif-ferent scientific areas. In addition, there is an ever increasing demand on fast and effective ways of computing DFT problems with large data sets. The FFTW library is one of the most common used libraries when computing DFTs. It adapts to the system architecture and predicts the most effective way of solving the input problem. Previous studies have proved the FFTW library to be superior to other DFT solving libraries. However, not many have specifically examined the cache memory performance, which is a key factor for overall performance. In this study, we examined the cache memory utilization when computing 1-D complex DFTs using the FFTW library. Testing was done using bench FFT, Linux Perf and testing scripts. The results from this study show that cache miss ratio increases with problem size when the input size is smaller than the theoretical input size matching the cache capacity. This is also verified by the results from the L2 prefetcher miss ratio. However, the study show that cache miss ratio stabilizes when exceeding the cache capacity. In conclusion, it is possible to use bench FFT and Linux Perf to measure cache memory utilization. Also, the analysis shows that cache memory performance is good when computing 1-D complex DFTS using the FFTW library, since the miss ratios stabilizes at low values. However, we suggest further examination ofthe memory behaviour for DFT computations using FFTW with larger input sizes and a more in-depth testing method.Diskret Fouriertransform (DFT) används inom många olika vetenskapliga områden. Det finns en ökande efterfrågan på snabba och effektiva sätt att beräkna DFT-problem med stora mängder data. FFTW-biblioteket är ett av de mest använda biblioteken vid beräkning av DFT-problem. FFTW-biblioteket anpassar sig till systemarkitekturen och försöker generera det mest effektiva sättet att lösa ett givet DFT-problem. Tidigare studier har visat att FFTW-biblioteket är effektivare än andra bibliotek som kan användas för att lösa DFT-problem. Däremot har studierna inte fokuserat på minneshanteringen, vilket är en nyckelfaktor för den generella prestandan. I den här studien undersökte vi FFTW-bibliotekets cache-minneshanteringen vid beräkning av 1-D komplexa DFT-problem. Tester utfördes med hjälp av bench FFT, Linux Perf och testskript. Resultaten från denna studie visar att cache-missförhållandet ökar med problemstorleken när problemstorleken ärmindre än den teoretiska problemstorleken som matchar cachekapaciteten. Detta bekräftas av resultat från L2-prefetcher-missförhållandet. Studien visar samtidigt att cache-missförhållandet stabiliseras när problemstorleken överskrider cachekapaciteten. Sammanfattningsvis går det att argumentera för att det är möjligt att använda bench FFT och Linux Perf för att mäta cache-minneshanteringen. Analysen visar också att cache-minneshanteringen är bra vid beräkning av 1-D komplexa DFTs med hjälp av FFTW-biblioteket eftersom missförhållandena stabiliseras vid låga värden. Vi föreslår dock ytterligare undersökning av minnesbeteendet för DFT-beräkningar med hjälp av FFTW där problemstorlekarna är större och en mer genomgående testmetod används.
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Dong, Jun 1971. "Development of Fourier transform infrared (FTIR) spectroscopy for determining oil quality." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27308.
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In this work, a rapid Fourier transform near infrared (FT-NIR) spectroscopic peroxide value (PV) method was developed and a prototype Continuous Oil Analysis and Treatment (COAT) system was assessed for monitoring and analytical purposes. High erucic acid rapeseed oil, a principle representative of triglyceride based oils suitable for biodegradable lubricating applications and mineral oil were used to test the methodology developed.The FT-NIR PV method is based on a well defined stoichiometric reaction of triphenylphospine (TPP) with hydroperoxides to form triphenylphospine oxide (TPPO). A partial least squares calibration model for the prediction of PV was developed using the NIR spectral region where TPP and TPPO co-absorb. The resulting calibration was highly linear over the analytical range of 100PV. Validation of the method carried out by comparing the PV of PLS prediction to the results of AOCS iodometric procedures indicated an excellent concurrence between the two methods. By programming the FT-NIR spectrometer, the analytical procedure simply consists of the addition of TPP stock solution to oil sample, mixing, taking its spectrum and predicting PV value. Through selected testing procedures, the prototype COAT system utilizing FTIR spectroscopy, advanced sample handling system designs, and computer programming was proved to be effective in monitoring the oil quality and behavior of antioxidants in real time.
Both approaches offer combined advantages of speed, accuracy, low labor cost, automation, and environmental friendliness mainly derived from FTIR spectroscopy, and can serve as convenient means for routine quality control applications in oils and fats industry. Potential application based on the joint usage of the two methods in the obtaining of true value of oil stability was also presented in this text. (Abstract shortened by UMI.)
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Sandström, Tobias. "Condition Monitoring of Ceramic Ball Bearings in an Engine Testing Dynamometer." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-183126.
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The choice of the topic addressed in this thesis aims to improve the service and maintenance on ceramic ball bearings in a specific test dynamometer and through an engineering approach develop tools for condition monitoring. The company connected to this thesis, AVL, is the world's largest privately owned company for development, simulation and testing technology of powertrains for passenger cars, trucks and large engines. Engine testing is a critical part of the business at AVL Sweden and unexpected bearing failure can result in long repair times and great economic losses due to loss of the testing time. In short terms, the methodological approach followed the following steps; first a thorough information retrieval regarding bearings and analysis was conducted. The search was deepened around areas such as hybrid ball bearings, bearing failure mechanisms, bearing defect frequencies, signal analysis and condition monitoring. After this a table for bearing damage detection was developed and a “step by step” guidance for condition monitoring. The tools where afterwards verified by simple testing to detect complications within the chosen system. The existing condition monitoring system that is used today revealed weaknesses as it lacked the feature of taking preventive measures. The system that is based on temperature measurements isn’t satisfactory enough, especially when it’s missing visual clarity. Service and maintenance according to specifications from the manufacturer should be scheduled to ensure operational and guarantees. Currently mounted accelerometers on the housing of the Dynas3 engine should be connected for collecting data and the total sum of energy should be calculated for simple monitoring of historical progression. This should be done by following the guidance in order to ensure proper data acquisition. The best way to implement condition monitoring showed to be by performing multi-parameter monitoring. The design of the condition monitoring system is highly connected to what to monitor and at what stage. One main consideration to keep in mind is that it’s very rare that manufacturing defects are the reason for bearing failure. Instead it derives from improper storage, transport, handling or dimensional errors and even in some cases by improperly implemented force analysis prior to bearing selection.Huvudämnet som behandlas i detta examensarbete syftar till att förbättra service och underhåll på keramiska kullager i en viss testdynamometer och genom ett ingenjörsmässigt tillvägagångsätt utveckla verktyg för tillståndsövervakning. Företaget som är ansluten till detta examensarbete är AVL som är världens största privatägda företag för utveckling, simulering och testteknik för drivlinor för personbilar, lastbilar och stora motorer. Motorprovning är en viktig del av verksamheten vid AVL Sverige, och ett oväntat lagerhaveri kan leda till långa reparationstider och stora ekonomiska förluster på grund av utebliven test tid. I korta termer följde den metod som använts följande steg, först genomfördes en grundlig informationssökning om lager och tillhörande analyser. Efter det fördjupades sökande kring områden som hybrida kullager, lagerskademekanismer, frekvenser kopplade till lagerskador, signalanalys och tillståndsövervakning. Efter detta framställdes en tabell för detektering av lagerskador, samt en ”steg för steg” guide för tillståndsövervakning. Verktygen för tillståndsövervakning kontrolleras efteråt, genom att enkla tester genomfördes för att upptäcka komplikationer inom det valda systemet. Det övervakningssystem som används idag avslöjade svagheter genom att sakna funktionen att vidta förebyggande åtgärder. System som är baserat på temperaturmätningar är inte tillräckligt tillfredsställande, speciellt när det saknar en visuell tydlighet. Den service och underhåll som enligt tillverkarens föreskrifter påvisas bör planeras för att säkerställa drift och garantier. Nuvarande monterade accelerometrar fästa vid motorhöljet bör anslutas för att insamla data, och den totala summan av energin bör beräknas för en enkel övervakning av det historiska utvecklingsförloppet. Detta bör göras genom att följa de riktlinjer som framställts för att säkerställa korrekt datainsamling. Det bäst passande sättet att genomföra tillståndsövervakning på i detta fall visade sig vara att utföra multiparameterövervakning. Framställningen av tillståndsövervakningssystemet är starkt förknippat med vad som skall övervakas och i vilket skede. En huvudsaklig bidragande faktor att komma ihåg är att det är mycket ovanligt att fabrikationsfel är orsaken till lagerhaveri. Istället härstammar haveriet från felaktig förvaring, transportering, hantering eller dimensioneringsfel och i vissa fall av felaktigt genomförd kraftanalys inför lagerval.
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Leung, Cleo D. M. "Overtone Characterization of Garner Headjoints Using Spectrographic Analysis and Fast Fourier Transforms." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1396523100.
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Ma, Kangming 1965. "Peroxide value and trans analyses by Fourier transform infrared (FTIR) spectroscopy." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36643.
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New Fourier transform infrared (FTIR) approaches for the quantitative determination of peroxide value (PV) and isolated trans analyses were investigated and developed. The FTIR-PV methods investigated were all based on the stoichiometric reaction of hydroperoxides and triphenylphosphine (TPP) which converts TPP to triphenylphosphine oxide (TPPO). A reference transmission cell (100 mum) method was developed based on the use of a unique TPPO absorption at 542 cm-1. This method covered PV values from 0--15 PV and was shown to be superior in accuracy and reproducibility to the standard American Oil Chemists Society (AOCS) iodometric method. Subsequently, the utility of disposable polyethylene cards, normally used only for qualitative analyses, was investigated for quantitative PV determination. A quantitative IR card method was successfully developed and shown to serve as a very simple, rapid and alternative means of carrying out PV analyses. TPP-impregnated cards were able to reproduce the transmission cell PV results to +/-1.12 PV, while the unimpregnated card was slightly more accurate (+/-0.92 PV). A third FTIR-PV method was developed specifically for the at-line monitoring of high PV fatliquors and employed a germanium attenuated total reflectance sample handling accessory. This method hinged on the use of a TPPO absorption band at 1118 cm-1, normally off scale when pathlengths of >3 mum are used, but is suited to the analysis of oils having very high PVs (>250). The successful quantitative use of the disposable polyethylene IR card to PV led to its study for the quantitative FTIR determination of the isolated trans content of fats and oils and margarines. The polyethylene card was shown to unique and useful properties, tending to inhibit fat crystallization and its inability to retain moisture. These two properties allowed trans determination to be carried out on melted, high trans fats, without heating the polyethylene substrate and also to analyze margarines
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Strauss, Arne Karsten. "Numerical Analysis of Jump-Diffusion Models for Option Pricing." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33917.
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Jump-diffusion models can under certain assumptions be expressed as partial integro-differential equations (PIDE). Such a PIDE typically involves a convection term and a nonlocal integral like for the here considered models of Merton and Kou. We transform the PIDE to eliminate the convection term, discretize it implicitly using finite differences and the second order backward difference formula (BDF2) on a uniform grid. The arising dense linear system is solved by an iterative method, either a splitting technique or a circulant preconditioned conjugate gradient method. Exploiting the Fast Fourier Transform (FFT) yields the solution in only $O(n\log n)$ operations and just some vectors need to be stored. Second order accuracy is obtained on the whole computational domain for Merton's model whereas for Kou's model first order is obtained on the whole computational domain and second order locally around the strike price. The solution for the PIDE with convection term can oscillate in a neighborhood of the strike price depending on the choice of parameters, whereas the solution obtained from the transformed problem is stabilized.Master of Science
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Sedman, Jacqueline. "Application of Fourier transform infrared spectroscopy in the analysis of edible fats and oil." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36833.
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The application of Fourier transform infrared (FTIR) spectroscopy in the assessment of oil quality and stability and the determination of the degree and type (cis or trans) of unsaturation of fats and oils was investigated. FTIR spectroscopy was shown to provide a rapid means of monitoring changes in oils undergoing oxidation or subjected to thermal stress. Absorption bands associated with common primary and secondary oxidation products were identified by relating them to those of spectroscopically representative reference compounds, and a quantitative approach based on the use of oils spiked with these reference compounds as calibration standards was proposed. A sample-handling accessory based on a heated 25-mum transmission flow cell and heated input and output lines was developed to facilitate the rapid analysis of oils and premelted fats in their neat form. Using this system, an FTIR edible oil analysis package was developed to simultaneously analyze for trans content, cis content, iodine value (IV), and saponification number (SN) of neat fats and oils, using partial-least-squares (PLS) calibrations based on pure triglycerides. An automated transmission-based peak height method for isolated trans isomer determination using the characteristic trans absorption band at 967 cm -1 in the spectrum of a neat fat or oil, ratioed against the spectrum of a trans-free oil, was also developed. A subsequent validation study involving the analysis of more than 100 oil samples demonstrated concurrence between the trans data obtained by the PLS and peak height FTIR methods as well as between IV results obtained by FTIR analysis and gas chromatography. In addition, the internal consistency of the IV, cis, and trans FTIR predictions provided strong experimental evidence that the FTIR edible oil analysis package measures all three parameters accurately. A PLS-based IV/trans method was developed for a heated single-bounce horizontal attenuated total reflectance (SB-HATR) sample-
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Mathiyaparanam, Jeyisanker. "Analysis of acoustic emission in cohesionless soil." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001715.
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Bergstedt, Edwin, Johan Földhazy, and Alexander Lundstjälk. "Vibration Analysis on AC Electric Arc Furnace." Thesis, KTH, Materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173354.
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A computerized Fast Fourier Transform system has been used to analyse vibration measurements sampled from a 100-ton electric arc furnace. It has been the hypothesis that patterns in the vibration data would correlate to specific events in the electric arc furnace during the melting process. The theory was that the vibration patterns would be most powerful in multiples of 50 Hz, as the electric arcs operate with a frequency of 50 Hz. It was concluded that the multiples of 50 Hz were dominant. Investigation was made regarding how the amount of scrap affects the amplitude in the vibrations after a defined amount of energy input. It was confirmed that the intensity of the vibrations decreased with increasing mass and basket volume. Another discovery was the M-shaped pattern at the beginning of the melting process. This pattern was statistically analysed. It was found that 71 % of the 41 charges showed an M-shaped correlation. The appearance of this M-shape was analysed regarding power usage, and steel-type. It was concluded that the steel type affected the appearance of the M-shape. The occurrence of flat-bath was also investigated. The theory was that the vibration data would be fairly constant with the occurrence of flat-bath. It was discovered that the vibration data experienced a somewhat constant behaviour towards the end of the melting process in approximately 57 % of the 41 charges. Difficulties were encountered regarding detection of patterns, and correlating them to specific conditions, due to the many parameters that affect the vibration measurements from charge to charge. It was concluded that vibration analysis are unlikely to be used as an absolute way to foresee every event in the electric arc furnace during each charge. But can rather serve as a statistical tool, upon which decisions of how the melting process should be conducted could be based on.
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Dubois, Janie. "Determination of peroxide value and anisidine value using Fourier transform infrared spectroscopy." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23391.
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Lipid oxidation has important consequences in the edible oil industry, producing compounds with sensory impact and thus reducing the economic value of the products. This work focused on the development of two Fourier transform infrared (FTIR) spectroscopy methods for the measurement of peroxide value (PV) and anisidine value (AV), representing the primary and secondary oxidation products of edible oils.The infrared method developed for PV determination was based on a mathematical treatment by the partial least squares method of the information contained in the spectral region between 3750 and 3150 cm$ sp{-1}$.
The second method developed considered aldehyde content and anisidine value, a measure of secondary oxidation products.
The two methods developed are rapid ($ sim$2 min/sample) and have the advantage of being automatable. An infrared system coupled to a computer can collect the spectrum of an oil, analyze it and present a report without the need for personnel trained in FTIR spectroscopy. The cost of such a system would rapidly be absorbed through savings on personnel cost, time and chemical reagents required for conventional chemical methods and as such provides a useful advance in quality control methodology for the edible oils sector. (Abstract shortened by UMI.)
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Pippig, Michael. "Massively Parallel, Fast Fourier Transforms and Particle-Mesh Methods: Massiv parallele schnelle Fourier-Transformationen und Teilchen-Gitter-Methoden." Doctoral thesis, Universitätsverlag der Technischen Universität Chemnitz, 2015. https://monarch.qucosa.de/id/qucosa%3A20398.
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The present thesis provides a modularized view on the structure of fast numerical methods for computing Coulomb interactions between charged particles in three-dimensional space. Thereby, the common structure is given in terms of three self-contained algorithmic frameworks that are built on top of each other, namely fast Fourier transform (FFT), nonequispaced fast Fourier transform (NFFT) and NFFT based particle-mesh methods (P²NFFT). For each of these frameworks algorithmic enhancement and parallel implementations are presented with special emphasis on scalability up to hundreds of thousands of parallel processes.
In the context of FFT massively parallel algorithms are composed from hardware adaptive low level modules provided by the FFTW software library. The new algorithmic NFFT concepts include pruned NFFT, interlacing, analytic differentiation, and optimized deconvolution in Fourier space with respect to a mean square aliasing error. Enabled by these generalized concepts it is shown that NFFT provides a unified access to particle-mesh methods. Especially, mixed-periodic boundary conditions are handled in a consistent way and interlacing can be incorporated more efficiently. Heuristic approaches for parameter tuning are presented on the basis of thorough error estimates.Die vorliegende Dissertation beschreibt einen modularisierten Blick auf die Struktur schneller numerischer Methoden für die Berechnung der Coulomb-Wechselwirkungen zwischen Ladungen im dreidimensionalen Raum. Die gemeinsame Struktur ist geprägt durch drei selbstständige und auf einander aufbauenden Algorithmen, nämlich der schnellen Fourier-Transformation (FFT), der nicht äquidistanten schnellen Fourier-Transformation (NFFT) und der NFFT-basierten Teilchen-Gitter-Methode (P²NFFT). Für jeden dieser Algorithmen werden Verbesserungen und parallele Implementierungen vorgestellt mit besonderem Augenmerk auf massiv paralleler Skalierbarkeit. Im Kontext der FFT werden parallele Algorithmen aus den Hardware adaptiven Modulen der FFTW Softwarebibliothek zusammengesetzt. Die neuen NFFT-Konzepte beinhalten abgeschnittene NFFT, Versatz, analytische Differentiation und optimierte Entfaltung im Fourier-Raum bezüglich des mittleren quadratischen Aliasfehlers. Mit Hilfe dieser Verallgemeinerungen bietet die NFFT einen vereinheitlichten Zugang zu Teilchen-Gitter-Methoden. Insbesondere gemischt periodische Randbedingungen werden einheitlich behandelt und Versatz wird effizienter umgesetzt. Heuristiken für die Parameterwahl werden auf Basis sorgfältiger Fehlerabschätzungen angegeben.
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Lenssen, Nathan. "Applications of Fourier Analysis to Audio Signal Processing: An Investigation of Chord Detection Algorithms." Scholarship @ Claremont, 2013. http://scholarship.claremont.edu/cmc_theses/704.
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The discrete Fourier transform has become an essential tool in the analysis of digital signals. Applications have become widespread since the discovery of the Fast Fourier Transform and the rise of personal computers. The field of digital signal processing is an exciting intersection of mathematics, statistics, and electrical engineering. In this study we aim to gain understanding of the mathematics behind algorithms that can extract chord information from recorded music. We investigate basic music theory, introduce and derive the discrete Fourier transform, and apply Fourier analysis to audio files to extract spectral data.
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King, Brian William, and n/a. "An experimental investigation of the effects of mouthpiece control on alto saxophone tone in the student player." University of Canberra. Education, 1993. http://erl.canberra.edu.au./public/adt-AUC20060814.133145.
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Good tone is one of an alto saxophone player's greatest assets and
consequently deserves high priority in training and pedagogy. The
current pedagogical literature gives little attention to tone production
on the saxophone. The mouthpiece is the link between the player and
the saxophone. This study examined the effect of the normal
mouthpiece pitch and the pitch range produced on the saxophone
mouthpiece on alto saxophone tone quality .
In this experimental study, recordings were made of forty-three
student alto saxophone players who performed tasks consisting of three
saxophone mouthpiece exercises and four short musical phrases on the
saxophone.
The tape recordings were used to provide a spectral analysis of the
tone samples by Fast Fourier Transform Analysis, and to allow
qualitative analysis by five expert judges. The judges used a
saxophone listening profile to provide qualitative evaluation of the
recordings.
Cluster analysis produced three groups of subjects according to
combinations of the mouthpiece pitch and range produced. The mean
sustained mouthpiece pitch and mouthpiece range of the groups were:
Cluster 1 - 790 Hz and 550 cents; Cluster 2 1023 Hz and 150 cents:
and Cluster 3 - 820 Hz and 1203 cents.
Analysis of variance was used to test for statistically significant
differences between the clusters. Discriminant analysis was used to
identify other variables which contributed to the formation of the three
clusters.
The quantitative analysis of both mouthpiece and saxophone tones
provided no insight into the spectra of the student subjects.
The qualitative analysis using bipolar descriptors provided valid
criteria which could be applied consistently for the analysis of student
saxophone tone. A Tonal Index was computed from the judges' ratings
in order to test for differences in tone between the clusters.
Analysis of variance tests showed significant differences in the tone
produced by the clusters on both the mouthpiece and the saxophone.
The tone produced by Cluster 3 was significantly different to that
produced by Clusters 1 and 2 at the p < .05 level.
Discriminant analysis identified the use of saxophone tone models
(through comparative critical listening) and small group performance as
significant predictor variables (at the p < .05 level) in the formation of
the clusters.
The results of this study suggest that tone production on the alto
saxophone is improved through the development of control on the
mouthpiece. It was concluded that routine practice with the
mouthpiece can serve in the development of a flexible and responsive
embouchure and oral cavity and that students need to develop a
mental concept of saxophone tone as part of the development of tone
production. Also, experience in small group performance needs to be
sought and provided for saxophone students. Finally, this study
focussed on an area of mouthpiece behaviour which can easily be
included into any instructional design and monitored by teachers.
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Blanchard, Pierre. "Fast hierarchical algorithms for the low-rank approximation of matrices, with applications to materials physics, geostatistics and data analysis." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0016/document.
Full textAbstract:
Les techniques avancées pour l’approximation de rang faible des matrices sont des outils de réduction de dimension fondamentaux pour un grand nombre de domaines du calcul scientifique. Les approches hiérarchiques comme les matrices H2, en particulier la méthode multipôle rapide (FMM), bénéficient de la structure de rang faible par bloc de certaines matrices pour réduire le coût de calcul de problèmes d’interactions à n-corps en O(n) opérations au lieu de O(n2). Afin de mieux traiter des noyaux d’interaction complexes de plusieurs natures, des formulations FMM dites ”kernel-independent” ont récemment vu le jour, telles que les FMM basées sur l’interpolation polynomiale. Cependant elles deviennent très coûteuses pour les noyaux tensoriels à fortes dimensions, c’est pourquoi nous avons développé une nouvelle formulation FMM efficace basée sur l’interpolation polynomiale, appelée Uniform FMM. Cette méthode a été implémentée dans la bibliothèque parallèle ScalFMM et repose sur une grille d’interpolation régulière et la transformée de Fourier rapide (FFT). Ses performances et sa précision ont été comparées à celles de la FMM par interpolation de Chebyshev. Des simulations numériques sur des cas tests artificiels ont montré que la perte de précision induite par le schéma d’interpolation était largement compensées par le gain de performance apporté par la FFT. Dans un premier temps, nous avons étendu les FMM basées sur grille de Chebyshev et sur grille régulière au calcul des champs élastiques isotropes mis en jeu dans des simulations de Dynamique des Dislocations (DD). Dans un second temps, nous avons utilisé notre nouvelle FMM pour accélérer une factorisation SVD de rang r par projection aléatoire et ainsi permettre de générer efficacement des champs Gaussiens aléatoires sur de grandes grilles hétérogènes. Pour finir, nous avons développé un algorithme de réduction de dimension basé sur la projection aléatoire dense afin d’étudier de nouvelles façons de caractériser la biodiversité, à savoir d’un point de vue géométriqueAdvanced techniques for the low-rank approximation of matrices are crucial dimension reduction tools in many domains of modern scientific computing. Hierarchical approaches like H2-matrices, in particular the Fast Multipole Method (FMM), benefit from the block low-rank structure of certain matrices to reduce the cost of computing n-body problems to O(n) operations instead of O(n2). In order to better deal with kernels of various kinds, kernel independent FMM formulations have recently arisen such as polynomial interpolation based FMM. However, they are hardly tractable to high dimensional tensorial kernels, therefore we designed a new highly efficient interpolation based FMM, called the Uniform FMM, and implemented it in the parallel library ScalFMM. The method relies on an equispaced interpolation grid and the Fast Fourier Transform (FFT). Performance and accuracy were compared with the Chebyshev interpolation based FMM. Numerical experiments on artificial benchmarks showed that the loss of accuracy induced by the interpolation scheme was largely compensated by the FFT optimization. First of all, we extended both interpolation based FMM to the computation of the isotropic elastic fields involved in Dislocation Dynamics (DD) simulations. Second of all, we used our new FMM algorithm to accelerate a rank-r Randomized SVD and thus efficiently generate multivariate Gaussian random variables on large heterogeneous grids in O(n) operations. Finally, we designed a new efficient dimensionality reduction algorithm based on dense random projection in order to investigate new ways of characterizing the biodiversity, namely from a geometric point of view
23
Clifford, Gari D. "Signal processing methods for heart rate variability analysis." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:5129701f-1d40-425a-99a3-59a05e8c1b23.
Full textAbstract:
Heart rate variability (HRV), the changes in the beat-to-beat heart rate calculated from the electrocardiogram (ECG), is a key indicator of an individual's cardiovascular condition. Assessment of HRV has been shown to aid clinical diagnosis and intervention strategies. However, the variety of HRV estimation methods and contradictory reports in this field indicate that there is a need for a more rigorous investigation of these methods as aids to clinical evaluation. This thesis investigates the development of appropriate HRV signal processing techniques in the context of pilot studies in two fields of potential application, sleep and head-up tilting (HUT). A novel method for characterising normality in the ECG using both timing information and morphological characteristics is presented. A neural network, used to learn the beat-to-beat variations in ECG waveform morphology, is shown to provide a highly sensitive technique for identifying normal beats. Fast Fourier Transform (FFT) based frequency-domain HRV techniques, which require re-sampling of the inherently unevenly sampled heart beat time-series (RR tachogram) to produce an evenly sampled time series, are then explored using a new method for producing an artificial RR tachogram. Re-sampling is shown to produce a significant error in the estimation of an (entirely specified) artificial RR tachogram. The Lomb periodogram, a method which requires no re-sampling and is applicable to the unevenly sampled nature of the signal is investigated. Experiments demonstrate that the Lomb periodogram is superior to the FFT for evaluating HRV measured by the LF/HF-ratio, a ratio of the low to high frequency power in the RR tachogram within a specified band (0.04-0.4 Hz). The effect of adding artificial ectopic beats in the RR tachogram is then considered and it is shown that ectopic beats significantly alter the spectrum and therefore must be removed or replaced. Replacing ectopic beats by phantom beats is compared to the case of ectopic-realted RR interval removal for the FFT and Lomb methods for varying levels of ectopy. The Lomb periodogram is shown to provide a signficantly better estimate of the LF/HF- ratio under these conditions and is a robust method for measuring the LF/HF-ratio in the presence of (a possibly unknown number of) ectpoic beats or artefacts. The Lomb peridogram and FFT-based techniques are applied to a database of sleep apnoeic and normal subjects. A new method of assessing HRV during sleep is proposed to minimise the confounding effects on HRV of changes due to changing mental activity. Estimation of LF/HF-ratio using the Lomb technique is shown to separate these two patient groups more effectively than with FFT-based techniques. Results are also presented for the application of these methods to controlled (HUT) studies on subjects with syncope, an autonomic nervous system problem, which indicate that the techniques developed in this thesis may provide a method for differentiating between sub-classes of syncope.
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ATTA-FOSU, THOMAS. "Fourier Based Method for Simultaneous Segmentation and Nonlinear Registration." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1492439037011351.
Full text
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Al-Shargabi, Tareq. "Spectral Analysis of Nonstationary Heart Rate of Neonates Receiving Therapeutic Hypothermia Treatment." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3273.
Full textAbstract:
We studied Heart Rate Variability (HRV) evolution during therapeutic hypothermia in newborns with hypoxic ischemic encephalopathy (HIE) using spectral analysis. We hypothesized that HRV measures are predictive of neurological outcome in babies with HIE. Non-stationarity in the data causes inaccurate quantification of the spectral power. A modification was proposed to power spectral analysis approach to mitigate the effect of non-stationarity. The modified and the standard approaches were applied to cardiac beat-to-beat intervals of newborns receiving hypothermia treatment. The performance of the approaches in distinguishing the RRi dynamics of two groups of newborns was assessed using area under the receiver operating characteristic (ROC) curve. Our results showed that the modified spectral analysis distinguished the two groups of neonates better than the standard approach. These results may be useful in identifying the deteriorating physiology of the infants receiving hypothermia treatment early in time and strategize alternate interventions for them.
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Homeili, Saeid. "Metrological characterisation of Low Power Voltage Transformers by using impulse response analysis." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20998/.
Full textAbstract:
this thesis presents a new approach in dealing with characterize LPVT and proposes determining the impulse response of LPVT, purposing to find transfer function (h(t)) which contains most electrical characteristics of LPVTs as a dynamic system.
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Schoeman, Mathilda Elizabeth. "Mango (Mangifera indica L.) kernel fat : fatty acid profile, oxidative stability and development of fourier transform near infrared (FT-NIR) spectroscopy calibration models." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52925.
Full textAbstract:
Thesis (MSc Food Sc )--Stellenbosch University, 2002.ENGLISH ABSTRACT: The oxidative stability of crude, cold-pressed mango kernel fat (MKF) was determined over a period of 240 days using the peroxide value (PV), conjugated diene value (CD) and p-anisidine value (AV) tests. The changes in fatty acid profile were monitored with gas chromatography and the oxidative status of MKF effectively predicted by FT-NIR spectroscopy. Results obtained from the different methods complemented each other and indicated the stable character of mango kernel fat against oxidative deterioration. The fatty acid profile constituted palmitic acid (CI6:0; 8.43%), stearic acid (CI8:0; 34.98%), oleic acid (CI8:1 cis; 48.05%), linoleic acid (CI8:2; 6.60%) and arachidic acid (C20:0; 1.73%). Trace amounts of C16:1 (0.56%), C18:1 trans (0.25%), C18:3 (0.43%), C20:1 (0.25%) and C22:0 (0.40%) were also found. The freshly pressed MKF had a peroxide value of 2.7 meq.kg", CD value of 0.07% and an AV of 2.2 mmol.kg", After 40 days of storage, the peroxide values of MKF stored with and without exposure to a limited amount of oxygen at 5, 15,25 and 40°C increased to 5 meq.kg" and 4 meq.kg" respectively. Emulsification of MKF had a stabilising effect (maximum PV = 2.8 meq.kg'), while exposure to UV light had a catalysing effect (maximum PV = 5 meq.kg'). These maximum values, decreased after 40 days. The CD values of MKF samples stored with and without exposure to oxygen at 5, 15,25 and 40°C increased to 0.18% and 0.16%, respectively at day 40. The CD values of samples exposed to light increased to 0_20% and the emulsified samples showed similar values to that of the MKF samples not exposed to oxygen. The conjugated diene values remained stable after day 40. The p-anisidine values of the MKF samples both stored with and without exposure to oxygen at 5, 15, 25 and 40°C varied between 0.5 and 5 mmol.kg". The weak correlation to the measurement of nonanal, as well as the low levels of 2-alkenals produced by the MKF, resulted in these low and sometimes non-linear values. The peroxide, conjugated diene and p-anisidine values obtained for MKF stored at 25°C over 240 days were low due to the low content of polyunsaturated fatty acids in MKF. This compared favourably with the higher values attained for sunflower, canola and olive oil, which are all rich in polyunsaturated fatty acids. The minimal changes observed in the fatty acid profile of mango kernel fat indicated the stability of the saturated fatty acids (CI6:0 and CI8:0) and oleic acid. In addition, the instability of linoleic and linolenic acids was evident due to oxidative deterioration. A decrease of 7.41% and 12.80% was observed between day 0 and 240 for the C18:2/C16:0 and C18:2/C18:0 ratios respectively. The prediction of the oxidative status of the MKF samples by near infrared spectroscopy were possible after the development of calibration models from a total data set of 300 samples of which one-third was used for independent validation. Principle component analysis (PCA) indicated classification at 0, 40 and the remaining (80 - 240) days. The best calibration model for PV yielded a SEP (standard error of prediction) of 0.46 meq.kg", correlation coefficient (r) of 0.95, bias of 0.02 and a root mean square error of prediction (RMSEP) of 0.46 meq.kg". The CD calibration model had a correlation coefficient of 0.89, SEP of 0.01 %, bias of 0.001 and RMSEP of 0.01% when developed on a data set with no pre-processing applied. The AV calibration had a SEP of 0.32 mmol.kg", bias of 0.03, RMSEP of 0.32 mmol.kg" and rof 0.93. The C18:2 and C18:3 models were built using partial least squares (PLS) regression and the values obtained for SEP were 0.31% and 0.054%, RMSEP 0.32% and 0.05%, bias 0.05 and 0.01 and correlation coefficcients were 0.82 and 0.54 respectively. The calibrations for CI8:1, C18:0 and C16:0 yielded weaker correlations. Good correlations were obtained when calibrating the CI8:2/CI6:0 and C18:2/CI8:0 ratios.
AFRIKAANSE OPSOMMING: Die oksidatiewe stabiliteit van ru, koud-geperste mango kern vet (MKV) (Mangifera indica L.) is oor 'n periode van 240 dae bepaal deur gebruik te maak van die peroksiedwaarde (PV), gekonjugeerde dieen waarde (CD) en p-anisidien waarde (AV) toetse. Die veranderinge in die vetsuurprofiel is gemonitor deur gaschromatografie en die oksidatiewe status van MKV is akkuraat voorspel word deur Fourier transformasie naby infrarooi (FT-NIR) spektroskopie. Die resultate van die verskillende toetsmetodes komplementeer mekaar goed en dui die stabiliteit van mango kern vet teen oksidatiewe verval aan. Die vetsuurprofiel is saamgestel uit palimitiensuur (C16:0; 8.43%), steariensuur (C18:0; 34.98%), oleïensuur (C18:1 cis; 48.05%), linoleïensuur (C18:2; 6.60%) en aragiedsuur (20:0; 1.73%). Spoorhoeveelhede C16:1 (0.56%), C18:1 trans (0.25%), C18:3 (0.43%), C20:1 (0.25%) en C22:0 (0.40%) is ook geïdentifiseer. Die vars geperste MKF het 'n peroksiedwaarde van 2.7 meq.kg", 'n CD waarde van 0.07% en 'n AV waarde van 2.2 mmol.kg" getoon. Na afloop van 40 dae opbergingsperiode by 5, 15, 25 en 40°C het die PV van MKV met 'n beperkte blootstelling aan suurstof na 5 meq.kg" vermeerder, terwyl die waardes van monsters sonder suurstofblootstelling na 4 meq.kg" vermeerder het. Emulsifisering van MKV het 'n stabiliserende effek (maksimum PV = 2.8 meq.kg") terwyl blootstelling aan ultraviolet (UV) lig 'n kataliserende effek (maksimum PV = meq.kgl ) op oksidasie gehad het. Hierdie maksimum waardes het na 40 dae afgeneem. Die CD waardes van MKF monsters opgeberg by 5, 15, 25 en 40°C en met beperkte blootstelling aan suurstof het vermeerder tot 0.18% terwyl die monsters sonder suurstofblootstelling by bogenoemde temperature vermeerder het tot 0.16% na 40 dae. Die gekonjugeerde dieen waardes van die monsters blootgestel aan UV lig het vermeerder tot 0.20%; terwyl die geëmulsifiseerde monsters waardes soortgelyk aan die MKV monsters sonder blootstelling aan suurstof getoon het. Gekonjugeerde dieen waardes het gestabiliseer vanaf dag 40. Die p-anisidienwaardes van MKV monsters opgeberg by temperature van 5,15, 25 en 40°C, met en sonder blootstelling aan suurstof, het varieer tussen 0.5 en 5 mmol.kg". Die swak korrellasie tussen nonanal produksie en p-anisidienwaardes, sowel as die klein hoeveelhede 2-alkenale geproduseer, was verantwoordelik vir hierdie lae en nie linêere waardes. Die peroksied, gekonjugeerde dieen en p-anisidienwaardes wat verkry is nadat MKV by 25°C in 240 opgeberg is, was laag weens die klein persentasie poli-onversadigde vetsure teenwoordig in die vet. Dit vergelyk goed met die hoë waardes wat verkry is vir sonneblom-, canola- en olyfolie wat almal ryk aan poli-onversadigde vetsure is. Die minimale veranderinge in die vetsuurprofiel van MKF dui op die stabiliserende invloed van versadigde vetsure (C16:0 en C18:0) en oleïensuur. Die onstabiliteit van linoleïen- en lineensuur duidelik uit hierdie vetsure se oksidatiewe verval. 'n Afname van 7.41% en 12.80% is waargeneem tussen dae 0 en 240 vir die C18:2/C16:0 en C18:2/C18:0 verhoudings, onderskeidelik. Die voorspelling van die oksidatiewe status van die MKF monsters met behulp van FT-NIR spektroskopie was moontlik deur die ontwikkeling van kalibrasie modelle. 'n Totale datastel van 300 monsters, waarvan ongeveer 'n derde vir validasie aangewend is, is gebruik vir die kalibrasiemodelle. Met behulp van PCA (hoojkomponent analise) kon drie klassifiseerbare groepe by 0, 40 en 80-240 dae onderskei word. Die beste kalibrasiemodel vir PV het 'n standaardfout van voorspelling (SEP) van 0.46 meq.kg", 'n korrellasiekoëffisient (r) van 0.95, 'n oorhelling van 0.02 en 'n standaardfout van voorspelling (RMSEP) van 0.46 meq.kg" gehad. Die CD kalibrasiemodel (geen voorafverwerking) het 'n r van 0.89, SEP van 0.01% oorhelling van 0.001 en RMSEP van 0.01% gehad. Die AV kalibrasie het 'n SEP van 0.32 mmol.kg', oorhelling van 0.03, RMSEP van 0.32 mmol.kg" en r van 0.93 gehad. Die C18:2 en C18:3 modelle is saamgestel deur PLS (partial least squares) regressie. Waardes verkry vir C18:2 en C18:3 was onderskeidelik: SEP 0.32% en 0.05%, RMSEP, 0.32% en 0.05%, oorhelling 0.05 en 0.01 en r 0.82 en 0.54. In die geval van C18:1, C18:0 en C16:0, het die kalibrasies swakker statistiek korrellasies getoon. Goeie korrellasies is verkry tydens kalibrasie vir die C18:2/C16:0 en C18:2/C18:0 verhoudings.
28
Russin, Ted Anthony. "A novel and rapid method to monitor the autoxidation of edible oils using Fourier transform infrared spectroscopy and disposable infrared cards /." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79119.
Full textAbstract:
A novel and rapid method was developed to monitor the autoxidation of edible oils by Fourier transform infrared (FTIR) spectroscopy with the use of disposable polymer infrared (PIR) cards having a microporous polytetrafluoroethylene (PTFE) sample substrate. Under conditions of mild heating (~58°C) and aeration, both model triacylglycerols (TAGS) and edible oils applied onto the PIR cards underwent rapidly accelerated oxidation. In order to compare the oxidative stability of samples on the PIR cards in terms of the time required to reach a peroxide value (PV) of 100 mequiv/kg oil, matching the end-point measured in the standard active oxygen method (AOM), an absorbance slope factor (ASF) was determined to relate changes in hydroperoxide (ROOH) absorbance (peak maximum found within the range of 3500--3200 cm-1 ) to PV. Similar ASF values were found for the four edible oils tested (safflower, canola, sunflower, and extra virgin olive oil), permitting determination of a pooled, universally applicable ASF value of 0.0526 mAbs/PV.
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Butler, Ivan Charles. "AN ANALYSIS OF RESISTANCE SPOT WELD QUALITY BASED ON ACOUSTIC AND ELECTRICAL SIGNATURES." UKnowledge, 2019. https://uknowledge.uky.edu/ms_etds/8.
Full textAbstract:
The union of a set of materials by way of Resistance Spot Welding is designed so that once fused together, a substantial amount of intentional, external force must be applied to separate the contents. Therefore, Resistance Spot Welding is often the preferred fusion method in high-volume manufacturing processes. The result of Resistance Spot Welding however is the formation of a weld nugget which is not visible to the naked eye. Destructive and/or ultrasonic methods applied off-line must be used to determine the quality of each weld; both inefficient and expensive processes. The following research analyzes the data fed back during resistance spot weld sequences in-line and establishes a correlation between emitted characteristics and the final quality of a spot weld.
The two characteristics researched to segregate weld quality are: the electrical sin wave signature and the acoustic sin wave signature produced during the welding sequence. Both features were discovered to have a direct correlation to the final quality of a weld once cured. By measuring and comparing these characteristics at the source, an opportunity is presented to decrease time and potential defects by confirming the quality of each weld in-process and at the source.
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Al-Alawi, Ahmed Ali. "Novel approaches to automated quality control analyses of edible oils by Fourier transform infrared spectroscopy : determination of free fatty acid and moisture content." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100311.
Full textAbstract:
Three new quantitative Fourier transform infrared (FTIR) spectroscopic methods were developed for the analysis of edible oils: two procedures to measure free fatty acids (FFA) and one to measure moisture (H2O), the latter two methods ultimately being automated and implemented on an auto-sampler equipped FTIR spectrometer. The methods developed for FFA determination both convert FFAs to their carboxylate salts by means of acid/base reaction without causing oil saponification, one approach using 1-propanol, an oil-miscible solvent, and the other using methanol, an oil-immiscible solvent into which the FFA salts are extracted. The first method involves splitting oil samples into two halves, with one half treated with propanol containing base and the other half with propanol only. The spectra of each half is collected and a differential spectrum obtained, from which quantization is performed. The methanol procedure simply involves extracting FFA into methanol containing a weak base and quantitating the FFA salts produced. Both FFA methods determine the FFA content by measuring the v (COO-) absorbance at ∼1570 cm-1 relative to a reference wavelength of 1820 cm-1 from a differential spectrum relative to the solvent, the extraction procedure being superior in terms of both speed and sensitivity, being able to measure FFA levels down to ∼0.001%. The method developed for moisture determination involves extracting water in edible oils into dry acetonitrile and then quantitating it by measuring the absorbance of the OH stretching band (3629 cm-1) and/or the HOH bending band (1631 cm -1). All three methods were validated by standard addition experiments, evaluated for potential interferences, and, in the case of FFA determination, compared to the performance of AOCS official methods. The results indicated that the extraction-based procedures were superior to conventional wet chemical methods in both sensitivity and reproducibility. The FFA and H2O extraction procedures were subsequently automated by connecting an auto-sampler to the FTIR spectrometer and developing procedures and software algorithms to enable the analysis of up to 100 samples/h. The methods developed and implemented are a substantive improvement over conventional methods for the analysis of FFA and H2O in edible oils and provide a means by which QC and process laboratories can analyze large volumes of edible oils for these two important parameters.
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Fanton, Laurent. "Estimation de l'âge au décès à partir de la 4ième côte." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/1248/.
Full textAbstract:
Dix observateurs ont évalué à la qualité de l'observation des variables sur lesquelles est fondée la méthode d'Iscan sur un échantillon de 59 4ième côtes droites de sujets masculins. Les résultats ont montré une pauvre reproductibilité et répétabilité de leur observation (test de Wilcoxon, coefficient Kappa) et mis en évidence les problèmes de la méthode. Une analyse mathématique géométrique et harmonique (FFT, descripteurs de Fourrier), ainsi qu'une sériation visuelle ont ensuite été réalisées sur un échantillon de 415 4ième côtes de sujets masculins. Les nouvelles variables objectivées ont permis de préciser la métamorphose de la 4ième côte avec l'âge et de poser les bases d'une nouvelle méthodeTen observers estimated the quality of the observation of the variables on which is based the Iscan’s method on a sample of 59 4th ribs harvested from males. Results showed poor reproducibility and repeatability for all three variables (Wilcoxon test, kappa-coefficient) and revealed problems in the method. A geometrical and harmonic mathematical analysis (Fast Fourier Transform, Fourier’s descriptors) and visual description was then provided on a sample of 415 4th ribs harvested from males. Then new objectivised variables allowed to clarify the metamorphosis of the 4th rib with the age and to give the bases for a new method
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Movin, Andreas, and Jonathan Jilg. "Kan datorer höra fåglar?" Thesis, KTH, Skolan för teknikvetenskap (SCI), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254800.
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Ljudigenkänning möjliggörs genom spektralanalys, som beräknas av den snabba fouriertransformen (FFT), och har under senare år nått stora genombrott i samband med ökningen av datorprestanda och artificiell intelligens. Tekniken är nu allmänt förekommande, i synnerhet inom bioakustik för identifiering av djurarter, en viktig del av miljöövervakning. Det är fortfarande ett växande vetenskapsområde och särskilt igenkänning av fågelsång som återstår som en svårlöst utmaning. Även de främsta algoritmer i området är långt ifrån felfria. I detta kandidatexamensarbete implementerades och utvärderades enkla algoritmer för att para ihop ljud med en ljuddatabas. En filtreringsmetod utvecklades för att urskilja de karaktäristiska frekvenserna vid fem tidsramar som utgjorde basen för jämförelsen och proceduren för ihopparning. Ljuden som användes var förinspelad fågelsång (koltrast, näktergal, kråka och fiskmås) så väl som egeninspelad mänsklig röst (4 unga svenska män). Våra resultat visar att framgångsgraden normalt är 50–70%, den lägsta var fiskmåsen med 30% för en liten databas och den högsta var koltrasten med 90% för en stor databas. Rösterna var svårare för algoritmen att särskilja, men de hade överlag framgångsgrader mellan 50% och 80%. Dock gav en ökning av databasstorleken generellt inte en ökning av framgångsgraden. Sammanfattningsvis visar detta kandidatexamensarbete konceptbeviset bakom fågelsångigenkänning och illustrerar såväl styrkorna som bristerna av dessa enkla algoritmer som har utvecklats. Algoritmerna gav högre framgångsgrad än slumpen (25%) men det finns ändå utrymme för förbättring eftersom algoritmen vilseleddes av ljud av samma frekvenser. Ytterligare studier behövs för att bedöma den utvecklade algoritmens förmåga att identifiera ännu fler fåglar och röster.Sound recognition is made possible through spectral analysis, computed by the fast Fourier transform (FFT), and has in recent years made major breakthroughs along with the rise of computational power and artificial intelligence. The technology is now used ubiquitously and in particular in the field of bioacoustics for identification of animal species, an important task for wildlife monitoring. It is still a growing field of science and especially the recognition of bird song which remains a hard-solved challenge. Even state-of-the-art algorithms are far from error-free. In this thesis, simple algorithms to match sounds to a sound database were implemented and assessed. A filtering method was developed to pick out characteristic frequencies at five time frames which were the basis for comparison and the matching procedure. The sounds used were pre-recorded bird songs (blackbird, nightingale, crow and seagull) as well as human voices (4 young Swedish males) that we recorded. Our findings show success rates typically at 50–70%, the lowest being the seagull of 30% for a small database and the highest being the blackbird at 90% for a large database. The voices were more difficult for the algorithms to distinguish, but they still had an overall success rate between 50% and 80%. Furthermore, increasing the database size did not improve success rates in general. In conclusion, this thesis shows the proof of concept and illustrates both the strengths as well as short-comings of the simple algorithms developed. The algorithms gave better success rates than pure chance of 25% but there is room for improvement since the algorithms were easily misled by sounds of the same frequencies. Further research will be needed to assess the devised algorithms' ability to identify even more birds and voices.
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McDermott, Matthew. "Fast Algorithms for Analyzing Partially Ranked Data." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/hmc_theses/58.
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Imagine your local creamery administers a survey asking their patrons to choose their five favorite ice cream flavors. Any data collected by this survey would be an example of partially ranked data, as the set of all possible flavors is only ranked into subsets of the chosen flavors and the non-chosen flavors. If the creamery asks you to help analyze this data, what approaches could you take? One approach is to use the natural symmetries of the underlying data space to decompose any data set into smaller parts that can be more easily understood. In this work, I describe how to use permutation representations of the symmetric group to create and study efficient algorithms that yield such decompositions.
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Gibson, Adam J. "Copresence, Communication Medium, and Solidarity in Task Groups." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1542310946564675.
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Broman, Simon, and André Franzén. "Analys av accelerometerdata för identifiering av träffpunkt och mätning av resulterande vibrationer i padelrack." Thesis, KTH, Hälsoinformatik och logistik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-296609.
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Syftet med att mäta vibrationer och rekyler i ett padelrack i detta arbete är att utveckla en prototyp som kan användas som träningsredskap för att minska risken för skador. En vanlig skada som drabbar padelspelare är tennisarmbåge, som enligt studier tros uppkomma genom upprepad exponering av mikrotrauman som vibrationer och rekyler. Genom att utföra en litteraturstudie i ämnet har systemkrav för ett sensorbaserat system definierats. Systemet som mäter vibrationer och rekyler har monterats i handtaget på padelracket. Två olika testmiljöer har utvecklats för att möjliggöra kontrollerade tester. För att identifiera och analysera slag använder systemet frekvensanalyser, korrelationstester och positionsförändring. Vid utveckling av metoden för identifiering av träffpunkt delades racket upp i fem olika zoner. Resultatet indikerar att träffar i två av zonerna ger upphov till mindre mängd vibrationer jämfört med de övriga zonerna. Resultatet för identifiering av träffzon varierar mellan testmiljöerna och enbart identifiering av en zon kan anses vara fungerande i båda fallen. Systemet identifierade träffzonen korrekt i 18 av 25 slag i den ena testmiljön och 9 av 25 i den andra. För att förbättra identifieringen av träffzon behövs flera analyser och korrelationtester utformas. En slutsats för det här examensarbetet är att det här arbetet kan användas som grund för vidare utveckling av ett sensorbaserat system för att identifiera träffzonen och kvantifiera vibrationer i ett padelrack.The purpose of measuring vibrations and recoils in a padel racket in this thesis is to develop a prototype that can be used as a training equipment to reduce the risk of injury. A common injury for padel players is tennis elbow, studies show that the cause of this injury are microtraumas from vibrations and recoils. Through a literature study in the subject, system demands for a sensor-based system have been defined. The system that has been used to measure vibrations and recoils have been attached to the bottom of the handle on the padel racket. To achieve controlled tests two different test environments have been developed. To identify and analyze impacts the system utilizes frequency analysis, correlation tests and displacement tracking. For identification of the impact area the racket was divided into five zones. The result indicates, that two of the impact zones generate less vibrations than the others. The result also shows that identification of impact zone varies between the test environments and that only the sweet spot can be identified in both cases. The system identified the impact zone correctly in 18 out of 25 strokes in one test environment and 9 out of 25 in the other. To further improve the methods for identification of the impact zone more analyses and correlations tests are required. One conclusion for this thesis is that it can be used as a platform for further development of a sensor-based system that can correctly identify impacts in all zones and quantify the resulting vibrations.
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Bertolino, Mattias. "Extended analysis of a pseudo-spectral approach to the vortex patch problem." Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-354422.
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A prestudy indicated superior accuracy and convergence properties of apseudo-spectral method compared to a spline-based method implemented byCòrdoba et al. in 2005 when solving the α-patches problem. In this thesis wefurther investigate the numerical properties of the pseudo-spectral method and makeit more robust by implementing the Nonequispaced Fast Fourier Transform. Wepresent a more detailed overview and analysis of the pseudo-spectral method and theα-patches problem in general and conclude that the pseudo-spectral method issuperior in regards to accuracy in periodic settings.
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Danisman, Batuhan. "Analysis Of Conventional Low Voltage Power Line Communication Methods For Automatic Meter Reading And The Classification And Experimental Verification Of Noise Types For Low Voltage Power Line Communication Network." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610469/index.pdf.
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In this thesis, the conventional low voltage power line communication methods is
investigated in the axis of automated meter reading applications and the classification
and experimental verification of common noise types for low voltage power line
communication network. The investigated system provides the real time transmission
of electricity consumption data recorded by electricity meters, initially to a local
computer via a low voltage line through a low speed PLC (Power Line Carrier)
environment and subsequently to a corporate network through a high speed data
transmission medium. The automated meter system provides a more effective
tracking and data acquisition, a more detailed and vigorous knowledge about
consumer behavior for subscriber assessment in electricity distribution in association
with a brand new management and system supervision concept in electricity
distribution control and management technology. The theoretical studies are
experimentally verified for the Turkish low voltage power infrastructure through
laboratory experiments performed in METU Electrical and Electronics Engineering
Department, Electrical Machines and Drives Laboratory and R&D Laboratories of MAKEL facilities in Hadimkö
y. The single phase voltage of the mains line between the phase and neutral is monitored to exhibit the disturbing effects of various noise sources. The resulting voltage spectrum is logged by using digital data acquisition devices in time and frequency domain. The waveforms are converted to frequency domain using the Fast Fourier Transform (FFT) functions of the MATLAB. The experimental results are compared to the theoretical findings obtained through literature survey.
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Bladyko, Daniil. "Rychlá Fourierova transformace a její využití při oceňování evropských spreadových opcí." Master's thesis, Vysoká škola ekonomická v Praze, 2017. http://www.nusl.cz/ntk/nusl-360565.
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This master thesis should provide reader with an overview of the European spread options evaluation using the fast Fourier transform numerical method. The first and second part of the thesis deal with the theoretical foundations of Fourier analysis and existing approaches of spread option valuation under two and three-factors frameworks (namely GBM - geometric Brown motion and SV - stochastic volatility). The third part describes extention of Hurd-Zhou (2010) valuation method by tool for call and put spread options pricing in case of negative or zero strikes. Extension will be compared with Monte Carlo simulation results from a variety of perspectives, including computing complexity and implementation requirements. Dempster-Hong model, Hurd-Zhou model and Monte Carlo simulation are implemented and tested in R (programming language).
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Kesarkar, Manali Subhash Zhang Chuanjun. "Low power Fast Fourier Transform Processor." Diss., UMK access, 2007.
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Thesis (M.S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2007."A thesis in electrical engineering." Typescript. Advisor: Chuanjun Zhang. Vita. Title from "catalog record" of the print edition Description based on contents viewed Dec. 18, 2007. Includes bibliographical references (leaves 83-84). Online version of the print edition.
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Mateer, Todd. "Fast Fourier Transform algorithms with applications." Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1219848251/.
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Hu, Richard 1982. "Optimizing a parallel fast Fourier transform." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28404.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 40).
Parallel computing, especially cluster computing has become more popular and more powerful in recent years. Star-P is a means of harnessing that power by eliminating the difficulties in parallelizing code and by providing the user with a familiar and intuitive interface. This paper presents methods to create a parallel FFT module for Star-P. We find that because calculating a parallel FFT is more communication-intensive than processor-intensive, clever planning and distribution of data is needed to achieve speed-up in a parallel environment.
by Richard Hu.
M.Eng.
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Basha, Elizabeth (Elizabeth Ann). "Fast Fourier transform on a 3D FPGA." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34373.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 53-55).
Fast Fourier Transforms perform a vital role in many applications from astronomy to cellphones. The complexity of these algorithms results from the many computational steps, including multiplications, they require and, as such, many researchers focus on implementing better FFT systems. However, all research to date focuses on the algorithm within a 2-Dimensional architecture ignoring the opportunities available in recently proposed 3-Dimensional implementation technologies. This project examines FFTs in a 3D context, developing an architecture on a Field Programmable Gate Array system, to demonstrate the advantage of a 3D system.
by Elizabeth Basha.
S.M.
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Maschhoff, Robert H., and Kyong H. Lee. "Data Compression Using the Fast Fourier Transform." International Foundation for Telemetering, 1988. http://hdl.handle.net/10150/615063.
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International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, NevadaThe Fast Fourier Transform (FFT) technique has long been used for spectral analysis but it has not been fully exploited for data compression purposes. This paper presents the concept for compressing telemetry data using the FFT in such a manner that the time domain waveform can be recovered. The sampled time-domain data is transformed into the frequency-domain data and only the significant components are selected and transmitted. Actual flight data is used to simulate the data compression performance. Some comparisons are made between this FFT approach and other possibilities.
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Fenn, Markus. "Fast fourier transform at nonequispaced nodes and applications." [S.l. : s.n.], 2006.
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Palmer, Joseph McRae. "The Hybrid Architecture Parallel Fast Fourier Transform (HAPFFT) /." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd855.pdf.
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Palmer, Joseph M. "The Hybrid Architecture Parallel Fast Fourier Transform (HAPFFT)." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/555.
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The FFT is an efficient algorithm for computing the DFT. It drastically reduces the cost of implementing the DFT on digital computing systems. Nevertheless, the FFT is still computationally intensive, and continued technological advances of computers demand larger and faster implementations of this algorithm. Past attempts at producing high-performance, and small FFT implementations, have focused on custom hardware (ASICs and FPGAs). Ultimately, the most efficient have been single-chipped, streaming I/O, pipelined FFT architectures. These architectures increase computational concurrency through the use of hardware pipelining. Streaming I/O, pipelined FFT architectures are capable of accepting a single data sample every clock cycle. In principle, the maximum clock frequency of such a circuit is limited only by its critical delay path. The delay of the critical path may be decreased by the addition of pipeline registers. Nevertheless this solution gives diminishing returns. Thus, the streaming I/O, pipelined FFT is ultimately limited in the maximum performance it can provide. Attempts have been made to map the Parallel FFT algorithm to custom hardware. Yet, the Parallel FFT was formulated and optimized to execute on a machine with multiple, identical, processing elements. When executed on such a machine, the FFT requires a large expense on communications. Therefore, a direct mapping of the Parallel FFT to custom hardware results in a circuit with complex control and global data movement. This thesis proposes the Hybrid Architecture Parallel FFT (HAPFFT) as an alternative. The HAPFFT is an improved formulation for building Parallel FFT custom hardware modules. It provides improved performance, efficient resource utilization, and reduced design time. The HAPFFT is modular in nature. It includes a custom front-end parallel processing unit which produces intermediate results. The intermediate results are sent to multiple, independent FFT modules. These independent modules form the back-end of the HAPFFT, and are generic, meaning that any prexisting FFT architecture may be used. With P back-end modules a speedup of P will be achieved, in comparison to an FFT module composed solely of a single module. Furthermore, the HAPFFT defines the front-end processing unit as a function of P. It hides the high communication costs typically seen in Parallel FFTs. Reductions in control complexity, memory demands, and logical resources, are achieved. An extraordinary result of the HAPFFT formulation is a sublinear area-time growth. This phenomenon is often also called superlinear speedup. Sublinear area-time growth and superlinear speedup are equivalent terms. This thesis will subsequently use the term superlinear speedup to refer to the HAPFFT's outstanding speedup behavior. A further benefit resulting from the HAPFFT formulation is reduced design time. Because the HAPFFT defines only the front-end module, and because the back-end parallel modules may be composed of any preexisting FFT modules, total design time for a HAPFFT is greatly reduced
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Brand, Tristan. "A Fast Fourier Transform for the Symmetric Group." Scholarship @ Claremont, 2006. https://scholarship.claremont.edu/hmc_theses/179.
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A discrete Fourier transform, or DFT, is an isomorphism from a group algebra to a direct sum of matrix algebras. An algorithm that efficiently applies a DFT is called a fast Fourier transform, or FFT. The concept of a DFT will be introduced and examined from both a general and algebraic perspective. We will then present and analyze a specific FFT for the symmetric group.
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Berta, Abaynesh. "Option Pricing using the Fast Fourier Transform Method." Thesis, Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-51058.
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The fast Fourier transform (FFT), even though it has been widely applicable in Physics and Engineering, it has become attractive in Finance as well for it’s enhancement of computational speed. Carr and Madan succeeded in implementing the FFT for pricing of an option. This project, inspired by Carr and Madan’s paper, attempts to elaborate and connect the various mathematical and theoretical concepts that are helpful in understanding of the derivation. Further, we derive the characteristic function of the risk neutral probability for the logarithmic terminal stock price. The Black-Scholes-Merton (BSM) model is also revised including derivation of the partial deferential equation and the formula. Finally, comparison of the BSM numerical implementation with and without the FFT method is done using MATLAB.
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Lingenbrink, David Alan Jr. "A New Subgroup Chain for the Finite Affine Group." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/hmc_theses/55.
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The finite affine group is a matrix group whose entries come from a finite field. A natural subgroup consists of those matrices whose entries all come from a subfield instead. In this paper, I will introduce intermediate sub- groups with entries from both the field and a subfield. I will also examine the representations of these intermediate subgroups as well as the branch- ing diagram for the resulting subgroup chain. This will allow us to create a fast Fourier transform for the group that uses asymptotically fewer opera- tions than the brute force algorithm.
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Jagtap, Vinod. "FAST FOURIER TRANSFORM USING PARALLEL PROCESSING FOR MEDICAL APPLICATIONS." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1270678206.
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