THE FOURIER SERIES USED IN ANALYSE OF THE CAM MECHANISMS FOR THE SHOEMAKING MACHINES (PART I
Directory of Open Access Journals (Sweden)
IOVAN-DRAGOMIR Alina
2016-05-01
Full Text Available A computer assisted procedure for the cinematic analysis of the mechanism of a cam is essential in making a certain type of research operations. They mainly refer to the optimization of operations running on specific machinery, or to the re-design of the mechanism, in order to make the mechanism digital. This analysis seems even more important, when we consider the fact that most of the machines used in shoe industry nowadays use a cam mechanism. The paper is devided in two parts. In first part, it is elaborated a method of finding of a function G(x, belonging to a Fourier series, which approximates the numerical values {xi, yi}, with the biggest accuracy. Finding the function that approximates the most accurately the data set, for the position parameters of the follower S(ω, ( will lead to a complete kinematic and dynamic analysis of the cam mechanism. These values repeat with T = 2π period. In second part, the method is tasted using MatCAD work sessions which allow a numerical and graphical analysis of the mathematical relations involved, in order to test the reability of the method. The set of experimental data are resulted after measuring a cam mechanism of a machine used in shoemaking.
Fourier Analysis and Structure Determination: Part I: Fourier Transforms.
Chesick, John P.
1989-01-01
Provides a brief introduction with some definitions and properties of Fourier transforms. Shows relations, ways of understanding the mathematics, and applications. Notes proofs are not included but references are given. First of three part series. (MVL)
Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses
Directory of Open Access Journals (Sweden)
Lucy Lim
2016-01-01
Full Text Available Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices.
A Fourier transform infrared trace gas analyser for atmospheric applications
Directory of Open Access Journals (Sweden)
D. W. T. Griffith
2012-05-01
Full Text Available Concern in recent decades about human impacts on Earth's climate has led to the need for improved and expanded measurement capabilities for greenhouse gases in the atmosphere. In this paper we describe in detail an in situ trace gas analyser based on Fourier Transform Infrared (FTIR spectroscopy that is capable of simultaneous and continuous measurements of carbon dioxide (CO_{2}, methane (CH_{4}, carbon monoxide (CO, nitrous oxide (N_{2}O and ^{13}C in CO_{2} in air with high precision and accuracy. Stable water isotopes can also be measured in undried airstreams. The analyser is automated and allows unattended operation with minimal operator intervention. Precision and accuracy meet and exceed the compatibility targets set by the World Meteorological Organisation – Global Atmosphere Watch Programme for baseline measurements in the unpolluted troposphere for all species except ^{13}C in CO_{2}.
The analyser is mobile and well suited to fixed sites, tower measurements, mobile platforms and campaign-based measurements. The isotopic specificity of the optically-based technique and analysis allows application of the analyser in isotopic tracer experiments, for example ^{13}C in CO_{2} and ^{15}N in N_{2}O. We review a number of applications illustrating use of the analyser in clean air monitoring, micrometeorological flux and tower measurements, mobile measurements on a train, and soil flux chamber measurements.
Atomic transition probabilities of Ce I from Fourier transform spectra
Lawler, J. E.; Chisholm, J.; Nitz, D. E.; Wood, M. P.; Sobeck, J.; Den Hartog, E. A.
2010-04-01
Atomic transition probabilities for 2874 lines of the first spectrum of cerium (Ce I) are reported. These data are from new branching fraction measurements on Fourier transform spectra normalized with previously reported radiative lifetimes from time-resolved laser-induced-fluorescence measurements (Den Hartog et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 085006). The wavelength range of the data set is from 360 to 1500 nm. Comparisons are made to previous investigations which are less extensive. Accurate Ce i transition probabilities are needed for lighting research and development on metal halide high-intensity discharge lamps.
Glasser, L.
1987-01-01
This paper explores how Fourier Transform (FT) mimics spectral transformation, how this property can be exploited to advantage in spectroscopy, and how the FT can be used in data treatment. A table displays a number of important FT serial/spectral pairs related by Fourier Transformations. A bibliography and listing of computer software related to…
The Symmetric Group Defies Strong Fourier Sampling: Part I
Moore, Cristopher; Schulman, L J; Moore, Cristopher; Russell, Alexander; Schulman, Leonard J.
2005-01-01
We resolve the question of whether Fourier sampling can efficiently solve the hidden subgroup problem. Specifically, we show that the hidden subgroup problem over the symmetric group cannot be efficiently solved by strong Fourier sampling, even if one may perform an arbitrary POVM on the coset state. Our results apply to the special case relevant to the Graph Isomorphism problem.
A Fourier transform infrared trace gas and isotope analyser for atmospheric applications
Directory of Open Access Journals (Sweden)
D. W. T. Griffith
2012-10-01
Full Text Available Concern in recent decades about human impacts on Earth's climate has led to the need for improved and expanded measurement capabilities of greenhouse gases in the atmosphere. In this paper we describe in detail an in situ trace gas analyser based on Fourier Transform Infrared (FTIR spectroscopy that is capable of simultaneous and continuous measurements of carbon dioxide (CO_{2}, methane (CH_{4}, carbon monoxide (CO, nitrous oxide (N_{2}O and ^{13}C in CO_{2} in air with high precision. High accuracy is established by reference to measurements of standard reference gases. Stable water isotopes can also be measured in undried airstreams. The analyser is automated and allows unattended operation with minimal operator intervention. Precision and accuracy meet and exceed the compatibility targets set by the World Meteorological Organisation – Global Atmosphere Watch for baseline measurements in the unpolluted troposphere for all species except ^{13}C in CO_{2}.
The analyser is mobile and well suited to fixed sites, tower measurements, mobile platforms and campaign-based measurements. The isotopic specificity of the optically-based technique and analysis allows its application in isotopic tracer experiments, for example in tracing variations of ^{13}C in CO_{2} and ^{15}N in N_{2}O. We review a number of applications illustrating use of the analyser in clean air monitoring, micrometeorological flux and tower measurements, mobile measurements on a train, and soil flux chamber measurements.
Directory of Open Access Journals (Sweden)
Hojat Gholizadeh
2015-04-01
Full Text Available This study was carried out to determine the protein and carbohydrate molecular structure of sorghum cultivars using Fourier Transform Infrared Spectroscopy (FTIR with multivariate molecular spectroscopy analyses. Sorghum cultivars included: 1- Kimia, 2- Sepideh, 3- M2 and 4- M8. Protein and carbohydrate molecular functional groups studied included: peak area and height amide I, amide II, α-helix, β-sheet, 860 (non-structure carbohydrate, 928 (non-structure carbohydrate, total carbohydrate (CHO with three major component peaks in this region, cellulosic compounds and different ratio of molecular structure. FTIR results showed that there were significant differences between sorghum cultivars in terms of proteins and carbohydrates molecular structures. Kimia had the greatest peak area and height amide I, II, α-helix, β-sheet, total carbohydrate and cellulosic compounds. Sepideh, M2 and M8 had similar proteins and carbohydrates molecular structures. Differences in protein and carbohydrate molecular structures can influence the availability of proteins and carbohydrates in ruminant and monogastric. Further studies needed to understand the effect of variety on protein and carbohydrate structure of sorghum and the relationship between protein and carbohydrate structure of a feed with nutrient availability in ruminant and monogastric
A note on the Fourier series model for analysing line transect data.
Buckland, S T
1982-06-01
The Fourier series model offers a powerful procedure for the estimation of animal population density from line transect data. The estimate is reliable over a wide range of detection functions. In contrast, analytic confidence intervals yield, at best, 90% confidence for nominal 95% intervals. Three solutions, one using Monte Carlo techniques, another making direct use of replicate lines and the third based on the jackknife method, are discussed and compared.
THE FOURIER SERIES USED IN ANALYSE OF THE CAM MECHANISMS FOR THE SHOEMAKING MACHINES (PART II
Directory of Open Access Journals (Sweden)
IOVAN-DRAGOMIR Alina
2016-05-01
Full Text Available A computer assisted procedure for the cinematic analysis of the mechanism of a cam is essential in making a certain type of research operations. They mainly refer to the optimization of operations running on specific machinery, or to the re-design of the mechanism, in order to make the mechanism digital. This analysis seems even more important, when we consider the fact that most of the machines used in shoe industry nowadays use a cam mechanism. The paper is devided in two parts. In first part, it is elaborated a method of finding of a function G(x, belonging to a Fourier series, which approximates the numerical values {xi, yi}, with the biggest accuracy. Finding the function that approximates the most accurately the data set, for the position parameters of the follower S(ω, ( will lead to a complete kinematic and dynamic analysis of the cam mechanism. These values repeat with T = 2π period. In second part, the method is tasted using MatCAD work sessions which allow a numerical and graphical analysis of the mathematical relations involved, in order to test the reability of the method. The set of experimental data are resulted after measuring a cam mechanism of a machine used in shoemaking.
Institute of Scientific and Technical Information of China (English)
CHAI A-li; WANG Yi-kai; ZHU Fa-di; SHI Yan-xia; XIE Xue-wen; LI Bao-ju
2016-01-01
Identification of plant-pathogenic fungi is time-consuming due to cultivation and microscopic exami-nation and can be influenced by the interpretation of the micro-morphological characters observed.The present investigation aimed to create a simple but sophisticated method for the identification of plant-pathogenic fungi by Fourier transform infrared (FTIR)spectroscopy.In this study,FTIR-attenuated total reflectance (ATR) spectroscopy was used in combination with chemometric analysis for identification of important pathogenic fun-gi of horticultural plants.Mixtures of mycelia and spores from 27 fungal strains belonging to nine different families were collected from liquid PD or solid PDA media cultures and subj ected to FTIR-ATR spectroscopy measurements.The FTIR-ATR spectra ranging from 4 000 to 400 cm-1 were obtained.To classify the FTIR-ATR spectra,cluster analysis was compared with canonical vitiate analysis (CVA)in the spectral regions of 3 050~2 800 and 1 800~900 cm-1 .Results showed that the identification accuracies achieved 97.53% and 9 9.1 8% for the cluster analysis and CVA analysis,respectively,demonstrating the high potential of this tech-nique for fungal strain identification.
Deardorff, N.; Cashman, K.
2014-12-01
The crust of lava flows (of all compositions) is commonly folded into arcuate ridges, bent such that the convex ridges point down flow. In theory, the geometry of flow surface folds can be used to constrain the thickness and viscosity of the folding layer (from the fold wavelength) and the compressional stress (from the fold amplitude). Crustal thickness is controlled primarily by lava composition and extent of cooling. Therefore, lavas of more evolved compositions (higher silica content) have thicker crusts, which should generate surface folds with larger wavelengths. We have determined the characteristic scale of surface folds using 1000m along-channel segments from Lidar-derived 3D Digital Terrain Models over a range of lava compositions (53-72 wt% SiO2). All profiles were analyzed by discrete Fourier transform (DFT) analysis in Matlab, used to determine the spatial scale of periodic surface features. The DFT periodograms produce 1D arrays of spectral density over a range of spatial frequencies, which describe the amplitude and spatial scale (wavelength) of lava surface topography. The DFT analysis allows for unbiased measurements of dominant surface fold wavelengths as well as identification of primary and secondary folds (i.e. folds within folds). Measurements of multiple fold generations are not possible from satellite images or in the field on intermediate to high silica blocky lavas. In our analyses, strong signals of surface periodicities were found at multiple frequencies for all lava flows, indicating multiple generations of surface folds. Additionally, mafic to intermediate lavas (65 wt% SiO2) which have a much larger range in dominant wavelength (10 - >100m). The deviation in expected dominant wavelengths for high silica flows is likely explained by effective viscosity, which is strongly influenced by lava crystallinity. Crystallization both adds solid particles to the lava, increasing the effective viscosity, and increases the silica content (and
Lagune de Salses - Leucate. I - Analyse bibliographique.
Ladagnous, Helene; Le Bec, Claude
1997-01-01
La mise en place récente de procédures visant à améliorer la qualité des eaux de la lagune de Salses-Leucate (Schéma d'Aménagement et de Gestion de l'Eau, contrat d'étang) nous a amenés à réaliser une synthèse des connaissances disponibles sur ce secteur, phase nécessaire et préalable à toute concertation. Il ressort de cette analyse bibliographique que bon nombre des études réalisées sont aujourd'hui obsolètes dans une perspective de gestion intégrée du site. Les connaissances hydrogéologiqu...
Analysing harmonic motions with an iPhone’s magnetometer
Yavuz, Ahmet; Kağan Temiz, Burak
2016-05-01
In this paper, we propose an experiment for analysing harmonic motion using an iPhone’s (or iPad’s) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone’s magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone’s screen using the Sensor Kinetics application. Data from this application was analysed with Eureqa software to establish the equation of the harmonic motion. Analyses show that the use of an iPhone’s magnetometer to analyse harmonic motion is a practical and effective method for small oscillations and frequencies less than 15-20 Hz.
Directory of Open Access Journals (Sweden)
G. E. A. Swann
2011-02-01
Full Text Available The development of a rapid and non-destructive method to assess purity levels in samples of biogenic silica prior to geochemical/isotope analysis remains a key objective in improving both the quality and use of such data in environmental and palaeoclimatic research. Here a Fourier Transform Infrared Spectroscopy (FTIR mass-balance method is demonstrated for calculating levels of contamination in cleaned sediment core diatom samples from Lake Baikal, Russia. Following the selection of end-members representative of diatoms and contaminants in the analysed samples, a mass-balance model is generated to simulate the expected FTIR spectra for a given level of contamination. By fitting the sample FTIR spectra to the modelled FTIR spectra and calculating the residual spectra, the optimum best-fit model and level of contamination is obtained. When compared to X-ray Fluorescence (XRF the FTIR method portrays the main changes in sample contamination through the core sequence, permitting its use in instances where other, destructive, techniques are not appropriate. The ability to analyse samples of <1 mg enables, for the first time, routine analyses of small sized samples. Discrepancies between FTIR and XRF measurements can be attributed to FTIR end-members not fully representing all contaminants and problems in using XRF to detect organic matter external to the diatom frustule. By analysing samples with both FTIR and XRF, these limitations can be eliminated to accurately identify contaminated samples. Future, routine use of these techniques in palaeoenvironmental research will therefore significantly reduce the number of erroneous measurements and so improve the accuracy of biogenic silica/diatom based climate reconstructions.
Swann, G. E. A.; Patwardhan, S. V.
2011-02-01
The development of a rapid and non-destructive method to assess purity levels in samples of biogenic silica prior to geochemical/isotope analysis remains a key objective in improving both the quality and use of such data in environmental and palaeoclimatic research. Here a Fourier Transform Infrared Spectroscopy (FTIR) mass-balance method is demonstrated for calculating levels of contamination in cleaned sediment core diatom samples from Lake Baikal, Russia. Following the selection of end-members representative of diatoms and contaminants in the analysed samples, a mass-balance model is generated to simulate the expected FTIR spectra for a given level of contamination. By fitting the sample FTIR spectra to the modelled FTIR spectra and calculating the residual spectra, the optimum best-fit model and level of contamination is obtained. When compared to X-ray Fluorescence (XRF) the FTIR method portrays the main changes in sample contamination through the core sequence, permitting its use in instances where other, destructive, techniques are not appropriate. The ability to analyse samples of <1 mg enables, for the first time, routine analyses of small sized samples. Discrepancies between FTIR and XRF measurements can be attributed to FTIR end-members not fully representing all contaminants and problems in using XRF to detect organic matter external to the diatom frustule. By analysing samples with both FTIR and XRF, these limitations can be eliminated to accurately identify contaminated samples. Future, routine use of these techniques in palaeoenvironmental research will therefore significantly reduce the number of erroneous measurements and so improve the accuracy of biogenic silica/diatom based climate reconstructions.
Directory of Open Access Journals (Sweden)
G. E. A. Swann
2010-09-01
Full Text Available The development of a rapid and non-destructive method to assess levels of purity in samples of biogenic silica prior to geochemical/isotope analysis remains a key objective in improving both the quality and use of such data in environmental and palaeoclimatic research. Here a Fourier Transform Infrared Spectroscopy (FTIR mass-balance method is demonstrated for calculating levels of contamination in cleaned sediment core diatom samples from Lake Baikal Russia. Following the selection of end-members representative of diatoms and contaminants in the analysed samples, a mass-balance model is generated to simulate the expected FTIR spectra for a given level of contamination. By fitting the sample FTIR spectra to the modelled FTIR spectra and calculating the Euclidean distance, the optimum “best-fit” model and level of contamination is obtained. When compared to X-ray Fluorescence (XRF, FTIR method results portray the main changes in sample contamination through the core sequence, permitting its use in instances where other, destructive, techniques are not appropriate. The ability to analyses samples of <1 mg enables, for the first time, routine analyses of small sized samples. Discrepancies between FTIR and XRF measurements can be attributed to FTIR end-members not fully representing all contaminants and problems in using XRF to detect organic matter external to the diatom frustule. By analysing samples with both FTIR and XRF, these limitations can be eliminated to accurately identify contaminated samples and improve the accuracy of climate reconstructions. Future, routine, use of these techniques in palaeoenvironmental research will significantly reduce the number of erroneous measurements and so improve the accuracy of biogenic silica/diatom based reconstructions.
Sun, Xin-Yuan; Xue, Jun-Fa; Xia, Zhi-Yue; Ouyang, Jian-Ming
2015-06-01
This study aimed to analyse the components of nanocrystallites in urines of patients with uric acid (UA) stones. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy (HRTEM), fast Fourier transformation (FFT) of HRTEM, and energy dispersive X-ray spectroscopy (EDS) were performed to analyse the components of these nanocrystallites. XRD and FFT showed that the main component of urinary nanocrystallites was UA, which contains a small amount of calcium oxalate monohydrate and phosphates. EDS showed the characteristic absorption peaks of C, O, Ca and P. The formation of UA stones was closely related to a large number of UA nanocrystallites in urine. A combination of HRTEM, FFT, EDS and XRD analyses could be performed accurately to analyse the components of urinary nanocrystallites.
Analysing Harmonic Motions with an iPhone's Magnetometer
Yavuz, Ahmet; Temiz, Burak Kagan
2016-01-01
In this paper, we propose an experiment for analysing harmonic motion using an iPhone's (or iPad's) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone's magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone's screen using the "Sensor Kinetics"…
Arrizabalaga, Iker; Gómez-Laserna, Olivia; Aramendia, Julene; Arana, Gorka; Madariaga, Juan Manuel
2014-08-14
This work studies the applicability of a Diffuse Reflectance Infrared Fourier Transform handheld device to perform in situ analyses on Cultural Heritage assets. This portable diffuse reflectance spectrometer has been used to characterise and diagnose the conservation state of (a) building materials of the Guevara Palace (15th century, Segura, Basque Country, Spain) and (b) different 19th century wallpapers manufactured by the Santa Isabel factory (Vitoria-Gasteiz, Basque Country, Spain) and by the well known Dufour and Leroy manufacturers (Paris, France), all of them belonging to the Torre de los Varona Castle (Villanañe, Basque Country, Spain). In all cases, in situ measurements were carried out and also a few samples were collected and measured in the laboratory by diffuse reflectance spectroscopy (DRIFT) in order to validate the information obtained by the handheld instrument. In the analyses performed in situ, distortions in the diffuse reflectance spectra can be observed due to the presence of specular reflection, showing the inverted bands caused by the Reststrahlen effect, in particular on those IR bands with the highest absorption coefficients. This paper concludes that the results obtained in situ by a diffuse reflectance handheld device are comparable to those obtained with laboratory diffuse reflectance spectroscopy equipment and proposes a few guidelines to acquire good spectra in the field, minimising the influence caused by the specular reflection.
Faglighed i pædagoguddannelsen - En kritisk analyse
Reedtz Funder, Laura
2016-01-01
Et kvalitativt studie af governmentality i pædagoguddannelsen 2014. Der etableres en teoretisk ramme med udgangspunkt i Foucaults metoder til historisk analyse. Hans magtbegreb og et poststrukturalistisk videnskabssyn. Projektet har udgangspunkt i Bacchis kritiske policybegreb. De empiriske data er produceret som kvalitative interviews, omkring praksis i governmentality i pædagoguddannelsen. Analysen formulerer, hvordan en ny pædagogfaglighed etableres i pædagoguddannelsen og et kritisk persp...
Kamalian, Morteza; Prilepsky, Jaroslaw E; Le, Son Thai; Turitsyn, Sergei K
2016-08-08
In this work, we introduce the periodic nonlinear Fourier transform (PNFT) method as an alternative and efficacious tool for compensation of the nonlinear transmission effects in optical fiber links. In the Part I, we introduce the algorithmic platform of the technique, describing in details the direct and inverse PNFT operations, also known as the inverse scattering transform for periodic (in time variable) nonlinear Schrödinger equation (NLSE). We pay a special attention to explaining the potential advantages of the PNFT-based processing over the previously studied nonlinear Fourier transform (NFT) based methods. Further, we elucidate the issue of the numerical PNFT computation: we compare the performance of four known numerical methods applicable for the calculation of nonlinear spectral data (the direct PNFT), in particular, taking the main spectrum (utilized further in Part II for the modulation and transmission) associated with some simple example waveforms as the quality indicator for each method. We show that the Ablowitz-Ladik discretization approach for the direct PNFT provides the best performance in terms of the accuracy and computational time consumption.
McGee, Kenneth A.; Elias, Tamar; Sutton, A. Jefferson; Doukas, Michael P.; Zemek, Peter G.; Gerlach, Terrence M.
2005-01-01
We report the results of a set of measurements of volcanic gases on two small ground level plumes in the vicinity of Pu`u `O`o cone on the middle East Rift Zone (ERZ) of Kilauea volcano, Hawai`i on 15 June 2001 using open-path Fourier transform infrared (FTIR) spectroscopy. The work was carried out as a reconnaissance survey to assess the monitoring and research value of FTIR measurements at this volcano. Despite representing emissions of residual volatiles from lava that has undergone prior degassing, the plumes contained detectable amounts of CO2, CO, SO2, HCl, HF and SiF4. Various processes, including subsurface cooling, condensation of water in the atmospheric plume, oxidation, dissolution in water, and reactions with wall rocks at plume vents affect the abundance of these gases. Low concentrations of volcanic CO2 measured against a high ambient background are not well constrained by FTIR spectroscopy. Although there appear to be some differences between these gases and Pu`u `O`o source gases, ratios of HCl/SO2, HF/SO2 and CO/SO2 determined by FTIR measurements of these two small plumes compare reasonably well with earlier published analyses of ERZ vent samples. The measurements yielded emission rate estimates of 4, 11 and 4 t d-1
Sideroudi, Haris; Labiris, Georgios; Georgatzoglou, Kimon; Ditzel, Fienke; Siganos, Charalambos; Kozobolis, Vassilios
PURPOSE: To evaluate the contribution of Fourier analysis of videokeratographic data in the diagnosis of subclinical keratoconus and keratoconus. SETTING: Eye Institute of Thrace, Democritus University, Alexandroupolis, Greece. DESIGN: Observational case series. METHODS: The following
Sideroudi, Haris; Labiris, Georgios; Georgatzoglou, Kimon; Ditzel, Fienke; Siganos, Charalambos; Kozobolis, Vassilios
2016-01-01
PURPOSE: To evaluate the contribution of Fourier analysis of videokeratographic data in the diagnosis of subclinical keratoconus and keratoconus. SETTING: Eye Institute of Thrace, Democritus University, Alexandroupolis, Greece. DESIGN: Observational case series. METHODS: The following Pentacam-deriv
Nathalie Merlin; Barbara Arruda Nogueira; Vanderlei Aparecido de Lima; Larissa Macedo dos Santos
2014-01-01
Agroindustrial waste in general presents significant levels of nutrients and organic matter and has therefore been frequently put to agricultural use. In this context, the objective of this study was to determine the chemical composition, nitrogen, phosphorus, potassium, calcium, magnesium and carbon content, as well as the qualitative characteristics through Fourier transform infrared spectroscopy of four samples of poultry litter and one sample of cattle manure, from the southwestern region...
Analyses of corium spreading in Mark I containment geometry
Energy Technology Data Exchange (ETDEWEB)
Sienicki, J.J.; Chu, C.C.; Farmer, M.T.
1991-12-31
An assessment of melt spreading in the Mark I system has been carried out using the MELTSPREAD-1 computer code together with supporting analyses. Application of MELTSPREAD-1 confirms the calculation of shell survival in a wet containment for the most probable melt release conditions from NUREG/CR-5423. According to MELTSPREAD-1, a dry containment also may not be threatened by melt spreading. This reflects the heat losses undergone by the melt in the process of spreading to the shell conservatively neglected in NUREG/CR-5423. However, there exist parameter ranges outside the most probable set where shell failure may be calculated. Accounting for the breakup and quenching of melt relocating through a deep layer of subcooled water also conservatively neglected in NUREG/CR-5423 can reduce the set of parameter variations for which containment failure is calculated in the wet case.
Analyses of corium spreading in Mark I containment geometry
Energy Technology Data Exchange (ETDEWEB)
Sienicki, J.J.; Chu, C.C.; Farmer, M.T.
1991-01-01
An assessment of melt spreading in the Mark I system has been carried out using the MELTSPREAD-1 computer code together with supporting analyses. Application of MELTSPREAD-1 confirms the calculation of shell survival in a wet containment for the most probable melt release conditions from NUREG/CR-5423. According to MELTSPREAD-1, a dry containment also may not be threatened by melt spreading. This reflects the heat losses undergone by the melt in the process of spreading to the shell conservatively neglected in NUREG/CR-5423. However, there exist parameter ranges outside the most probable set where shell failure may be calculated. Accounting for the breakup and quenching of melt relocating through a deep layer of subcooled water also conservatively neglected in NUREG/CR-5423 can reduce the set of parameter variations for which containment failure is calculated in the wet case.
A Fourier-Riccati approach to radiative transfer. Part I: Foundations
Energy Technology Data Exchange (ETDEWEB)
Gabriel, P.M.; Tsay, S.C.; Stephens, G.L. (Colorado State Univ., Fort Collins, CO (United States))
1993-09-15
The three-dimensional equation of radiative transfer is formally solved using a Fourier-Riccati approach while calculations are performed on cloudy media embedded in a two-dimensional space. An extension to Stephens' work, this study addresses the coupling between space and angle asserted by the equation of transfer. In particular, the accuracy of the computed radiation field as it is influenced by the angular resolution of the phase function and spatial discretization of the cloudy medium is discussed. The necessity of using a large number of quadrature points to calculate fluxes even when the phase function is isotropic for media exhibiting vertical and horizontal inhomogeneities is demonstrated. Effects of incorrect spatial sampling on both radiance and flux fields are also quantified by example. Radiance and flux comparison obtained by the Fourier-Riccati model and the independent pixel approximation for inhomogeneous cloudy media illustrate the inadequacy of the latter even for tenuous clouds. 34 refs., 11 figs., 1 tab.
Analytical determination of orbital elements using Fourier analysis. I. The radial velocity case
Delisle, J.-B.; Ségransan, D.; Buchschacher, N.; Alesina, F.
2016-05-01
We describe an analytical method for computing the orbital parameters of a planet from the periodogram of a radial velocity signal. The method is very efficient and provides a good approximation of the orbital parameters. The accuracy is mainly limited by the accuracy of the computation of the Fourier decomposition of the signal which is sensitive to sampling and noise. Our method is complementary with more accurate (and more expensive in computer time) numerical algorithms (e.g. Levenberg-Marquardt, Markov chain Monte Carlo, genetic algorithms). Indeed, the analytical approximation can be used as an initial condition to accelerate the convergence of these numerical methods. Our method can be applied iteratively to search for multiple planets in the same system.
Hogan, J D; Laude, D A
1990-11-01
The superior sensitivity , dynamic range, and mass measurement accuracy of suspended trapping pulse sequences for gas chromatography combined with Fourier transform mass spectrometry (GC/FTMS) separations of complex organic mixtures is demonstrated. By combining intense ionization conditions with a suspended trapping event prior to detection the working range of the trapped ion cell is increased by 10(3) . Improved detection limits are shown for the GC/FTMS separation of a peppermint oil, with the suspended trapping total ion chromatogram yielding 28 peaks, compared with 15 with a conventional trapping pulse sequence. A fivefold to fifteenfold improvement in signal-to-noise for suspended trapping measurements is also demonstrated with comparison spectra from separations of an unleaded gasoline sample. Suspended trapping spectra show little mass discrimination when an external ion reservoir is used, and chromatographic peak heights differ from conventional spectra by less than 30% if the initial ion population is within the space charge limit of the cell. Finally, average wide band mass measurement errors for components differing in concentration by several orders of magnitude are improved by a factor of 6 to 20 with suspended trapping compared with conventional trapping . For example, average errors of 8.7 ppm are obtained for a suspended trapping GC/FTMS separation of peppermint oil from a single calibration table in which the analysis is perfonned in the absence of calibrant.
Energy Technology Data Exchange (ETDEWEB)
Becker, D.L.
1994-11-01
Accelerated Safety Analyses - Phase I (ASA-Phase I) have been conducted to assess the appropriateness of existing tank farm operational controls and/or limits as now stipulated in the Operational Safety Requirements (OSRs) and Operating Specification Documents, and to establish a technical basis for the waste tank operating safety envelope. Structural sensitivity analyses were performed to assess the response of the different waste tank configurations to variations in loading conditions, uncertainties in loading parameters, and uncertainties in material characteristics. Extensive documentation of the sensitivity analyses conducted and results obtained are provided in the detailed ASA-Phase I report, Structural Sensitivity Evaluation of Single- and Double-Shell Waste Tanks for Accelerated Safety Analysis - Phase I. This document provides a summary of the accelerated safety analyses sensitivity evaluations and the resulting findings.
Performance analyses and optimization based on iSCSI
Institute of Scientific and Technical Information of China (English)
LI Wei-ming; LI Zhi-tang; XIANG Dong; XIE Yun-feng
2005-01-01
The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI subsystems is measured, which reveals that the main overhead is caused by protocol processing as well as kernel functions for fair allocation of system resources. Several methods have been proposed to optimize iSCSI subsystems, such as small I/O requests adherent that can be merged into a large I/O request. Checksum is found to be a time consuming work and may not be always necessary for applications.
Tolstov, Georgi P
1962-01-01
Richard A. Silverman's series of translations of outstanding Russian textbooks and monographs is well-known to people in the fields of mathematics, physics, and engineering. The present book is another excellent text from this series, a valuable addition to the English-language literature on Fourier series.This edition is organized into nine well-defined chapters: Trigonometric Fourier Series, Orthogonal Systems, Convergence of Trigonometric Fourier Series, Trigonometric Series with Decreasing Coefficients, Operations on Fourier Series, Summation of Trigonometric Fourier Series, Double Fourie
Cultural Studies og kritisk diskurs analyse i 8. klasse
DEFF Research Database (Denmark)
Svarstad, Lone Krogsgaard
2015-01-01
to be multiplicative and dynamic and power is foregrounded. Critical discourse analysis is used as a tool in class to analyse a dispute on Facebook between Miley Cyrus and Sinead O’Connor. Students work with active construction, making connections, social interaction, reflection, responsibility and they do so...
Genetic, molecular and functional analyses of complement factor I deficiency
DEFF Research Database (Denmark)
Nilsson, S.C.; Trouw, L.A.; Renault, N.;
2009-01-01
Complete deficiency of complement inhibitor factor I (FI) results in secondary complement deficiency due to uncontrolled spontaneous alternative pathway activation leading to susceptibility to infections. Current genetic examination of two patients with near complete FI deficiency and three...
The analysis of linear partial differential operators I distribution theory and Fourier analysis
Hörmander, Lars
2003-01-01
The main change in this edition is the inclusion of exercises with answers and hints. This is meant to emphasize that this volume has been written as a general course in modern analysis on a graduate student level and not only as the beginning of a specialized course in partial differen tial equations. In particular, it could also serve as an introduction to harmonic analysis. Exercises are given primarily to the sections of gen eral interest; there are none to the last two chapters. Most of the exercises are just routine problems meant to give some familiarity with standard use of the tools introduced in the text. Others are extensions of the theory presented there. As a rule rather complete though brief solutions are then given in the answers and hints. To a large extent the exercises have been taken over from courses or examinations given by Anders Melin or myself at the University of Lund. I am grateful to Anders Melin for letting me use the problems originating from him and for numerous valuable comm...
Stade, Eric
2005-01-01
A reader-friendly, systematic introduction to Fourier analysis Rich in both theory and application, Fourier Analysis presents a unique and thorough approach to a key topic in advanced calculus. This pioneering resource tells the full story of Fourier analysis, including its history and its impact on the development of modern mathematical analysis, and also discusses essential concepts and today's applications. Written at a rigorous level, yet in an engaging style that does not dilute the material, Fourier Analysis brings two profound aspects of the discipline to the forefront: the wealth of ap
Cultural Studies og kritisk diskurs analyse i 8. klasse
DEFF Research Database (Denmark)
Svarstad, Lone Krogsgaard
2015-01-01
to be multiplicative and dynamic and power is foregrounded. Critical discourse analysis is used as a tool in class to analyse a dispute on Facebook between Miley Cyrus and Sinead O’Connor. Students work with active construction, making connections, social interaction, reflection, responsibility and they do so...... thesis in the school year 2013-2014.The approach is based on Cultural Studies and knowledge of social categories and representation, and how these can be taught and discussed in class through an intersectional lens. An intersectional lens allows for the conceptualization of categories...
Supply Chain Management i danske virksomheder: En empirisk analyse
DEFF Research Database (Denmark)
Pedersen, Anne; Arlbjørn, Jan Stentoft; Haas, Henning de
Formålet med denne undersøgelse er at tage temperaturen på supply chain management-praksis i danske virksomheder. Specifikt søges praksis afdækket inden for følgende fem områder: (1) Supply chain-strategi og -organisation, (2) Outsourcing, (3) Integration med kunder, (4) Sourcing og (5) It....
Cost-benefit analyse af oplysninger i årsrapporten
DEFF Research Database (Denmark)
Riise Johansen, Thomas; Plenborg, Thomas
2012-01-01
regnskabsproducenter, har afdækket områder, hvor der forekommer ubalancer i årsrapporterne. Det gælder eksempelvis CRS og Corporate Governance, hvor efterspørgslen er begrænset og langt fra står mål med de anvendte ressourcer. Til gengæld efterspørges der information om teknisk vanskelige områder med et væsentligt...
Supply Chain Management i danske virksomheder: En empirisk analyse
DEFF Research Database (Denmark)
Pedersen, Anne; Arlbjørn, Jan Stentoft; Haas, Henning de
Formålet med denne undersøgelse er at tage temperaturen på supply chain management-praksis i danske virksomheder. Specifikt søges praksis afdækket inden for følgende fem områder: (1) Supply chain-strategi og -organisation, (2) Outsourcing, (3) Integration med kunder, (4) Sourcing og (5) It....
Mesons in strong magnetic fields: (I) General analyses
Hattori, Koichi; Su, Nan
2015-01-01
We study properties of neutral and charged mesons in strong magnetic fields |eB|>> Lambda_QCD^2 with Lambda_QCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger-Dyson and Bethe-Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number of meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B^2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compare...
NATO i krigen mot terror : En analyse av NATOs rolle i Afghanistan etter 11. september
Berg-Hansen, Susanne
2007-01-01
Denne oppgaven studerer NATOs rolle i den USA-ledede Operation Enduring Freedom i Afghanistan. Noen timer etter terrorangrepet mot USA 11. september 2001, påkalte NATO for første gang i historien sin grunnpilar, Artikkel 5 i NATO-traktaten, som fastslår at et angrep på ett av medlemmene er et angrep på alle NATO-landene. Til tross for alliansens påkallelse av Artikkel 5, ble NATO stående på sidelinjen i hovedfasen av "Operation Enduring Freedom". USA valgte å gjennomføre mesteparten av kamp...
Muñoz Morales, Aarón A; Vázquez Y Montiel, Sergio
2012-10-01
The determination of optical parameters of biological tissues is essential for the application of optical techniques in the diagnosis and treatment of diseases. Diffuse Reflection Spectroscopy is a widely used technique to analyze the optical characteristics of biological tissues. In this paper we show that by using diffuse reflectance spectra and a new mathematical model we can retrieve the optical parameters by applying an adjustment of the data with nonlinear least squares. In our model we represent the spectra using a Fourier series expansion finding mathematical relations between the polynomial coefficients and the optical parameters. In this first paper we use spectra generated by the Monte Carlo Multilayered Technique to simulate the propagation of photons in turbid media. Using these spectra we determine the behavior of Fourier series coefficients when varying the optical parameters of the medium under study. With this procedure we find mathematical relations between Fourier series coefficients and optical parameters. Finally, the results show that our method can retrieve the optical parameters of biological tissues with accuracy that is adequate for medical applications.
Comparison of the EPOC and i-STAT analysers for canine blood gas and electrolyte analysis.
West, E; Bardell, D; Senior, J M
2014-03-01
A prospective study to evaluate agreement and precision of a new point-of-care portable analyser, the EPOC analyser, compared with the i-STAT analyser in canine blood. Blood samples (68 venous and 32 arterial) were obtained from 63 client-owned dogs for clinical reasons and surplus blood was used to analyse agreement between the EPOC and i-STAT analysers. Precision of the EPOC analyser was also assessed by repeat analysis of 20 samples. Measured analytes included pH, partial pressures of carbon dioxide and oxygen and concentrations of sodium, potassium, ionised calcium, glucose and haematocrit. Haemoglobin, base excess, bicarbonate and saturation of haemoglobin with oxygen were calculated. EPOC precision was acceptable, but agreement was poor for sodium, haematocrit, haemoglobin and base excess. Overall, method comparison was poor for pH, partial pressure of oxygen, sodium, haematocrit, haemoglobin and base excess. The EPOC analyser is useful for dogs, although clinically significant differences between the EPOC and i-STAT analysers exist for some analytes, and as such these analysers should not be used interchangeably. © 2014 British Small Animal Veterinary Association.
Epidemiological analyses on animal parasitoses: recent activity of the I.M.I.P.P.V.
Battelli, G; Capelli, G; Martini, M; Poglayen, G; Restani, R; Roda, R
1989-01-01
The paper presents a selected review of the epidemiological analyses performed in recent years (1984-1988) in the Institute of Malattie Infettive, Profilassi e Polizia Veterinaria of the University of Bologna on animal parasitoses, with special reference to the evaluation of some risk factors of bovine, swine and canine helminthoses, and to the validity of the coprological test for some parasites of the red fox.
Energy Technology Data Exchange (ETDEWEB)
Krapez, J.C.; Spagnolo, L. [Politechnique di Bari (Italy); Friess, M. [Deutsches Luft- und Raumfahrtzentrum eV (DLR), Stuttgart (Germany); Maier, H.P. [Stuttgart Univ., MPA (Germany); Neuer, G. [Institut fur Kernenergetik und Energiesysteme, Universitat Stuttgart (Germany)
2003-07-01
The through-thickness thermal diffusivity can be evaluated by the classical flash method. If an homogeneous and extended source is used to irradiate the surface and a thermographic camera is used to monitor the temperature evolution of the opposite side, a map of the through-thickness thermal diffusivity can be obtained in a single experiment and without any contact with the sample under inspection. In order to measure the in-plane thermal diffusivity of a plate-like sample or in one of the principal directions of its plane, a thermal gradient across the plane of the material has to be settled. The ratio of the Fourier transform of temperature at two different spatial frequencies is an exponential function of time multiplied by the diffusivity in the considered principal direction. This can be used to evaluate the diffusivity in an homogenous material. In order to maximize the signal-to-noise ratio, it is better if heat is absorbed over a series of periodic parallel strips (grid flash method). When the material presents a transverse gradient of conductivity, we propose, as a first approach, to perform the Fourier analysis over a sliding window corresponding to one period of the grid pattern. This method allowed us to quantify in situ the diffusivity decrease in a tensile composite sample due to the stress-induced density increase of transverse microcracks. We finally analysed a more rigorous method for transverse conductivity profile inversion. It is based on a perturbation method. The analytical expression of the 'transfer function' between the Fourier transform of the temperature contrast and the Fourier transform of conductivity was established. We validated the proposed inverse technique on simulated and noise-corrupted thermograms. The approach is robust and the simulated profiles are very well resolved. (authors)
Institute of Scientific and Technical Information of China (English)
旷桂兰; 王道波; 吴伟力; 岳林; 姚峥嵘
2009-01-01
基于分数阶Fourier变换(FRFT)时-频分析理论的特点,构造信号验证了FRFT能解除时频偶合的特性.在此基础上,采用FRFT对某涡轴发动机典型的喘振试验数据进行喘振特征信号提取,然后基于有效特征信号的FRFT功率谱进行喘振瞬时频率的估计.结果表明:利用旋转角与喘振特征相匹配分数阶Fourier变换的能量聚集特性,能有效提取发动机喘振特征信号,并能利用FRFT结果,采用最优信号提取旋转角下的FRFT功率谱进行喘振瞬时频率的估计.%The article constructed signal to simulate the fractional Fourier transform (FRFT)'s characteristics of time-frequency analysis and validated that FRFT can relieve time and frequency coupling effectively.Then,typical surge experiment data of a turbine-shaft engine were processed using FRFT in order to pick up surge characteristic signal.With the FRFT energy spectrum of the surge characteristic signal,we evaluated the instantaneous surge frequency.The results show that using the characteristics of FRFT's energy congregation in the rotary angle,which matches with the engine surge's peculiarity,helps pick up the engine's surge characteristics signal effectively; using the FRFT energy spectrum helps estimate the instantaneous surge frequency.
Kvernadze, George; Hagstrom,Thomas; Shapiro, Henry
1997-01-01
A key step for some methods dealing with the reconstruction of a function with jump discontinuities is the accurate approximation of the jumps and their locations. Various methods have been suggested in the literature to obtain this valuable information. In the present paper, we develop an algorithm based on identities which determine the jumps of a 2(pi)-periodic bounded not-too-highly oscillating function by the partial sums of its differentiated Fourier series. The algorithm enables one to approximate the locations of discontinuities and the magnitudes of jumps of a bounded function. We study the accuracy of approximation and establish asymptotic expansions for the approximations of a 27(pi)-periodic piecewise smooth function with one discontinuity. By an appropriate linear combination, obtained via derivatives of different order, we significantly improve the accuracy. Next, we use Richardson's extrapolation method to enhance the accuracy even more. For a function with multiple discontinuities we establish simple formulae which "eliminate" all discontinuities of the function but one. Then we treat the function as if it had one singularity following the method described above.
Ayres, T. R.; Testerman, L.
1981-01-01
Measurements of the 2200/cm fundamental and 4300/cm first overtone vibration-rotation band systems of solar carbon monoxide, were obtained with the Fourier Transform Spectrometer of the McMath telescope at Kitt Peak. The overtone measurements were taken at the east, north, and west heliocentric limbs, and at disk center. Observations of the strong fundamental bands were obtained at disk center and near the north limb. The low core brightness temperatures of the strongest fundamental carbon monoxide lines near the limb, reported previously by Noyes (1972) and Hall (1974), are confirmed. The possibility that thermal inhomogeneities might be responsible for the unusual behavior of the fundamental carbon dioxide lines have been examined. The somewhat discordant behavior of the fundamental lines at disk center compared with the north limb seems to favor a limb shadowing effect. The first overtone limb equivalent widths and the best-fit thermal and microvelocity models indicate a solar carbon abundance of 0.004 (on the scale with A sub H = 1) for an oxygen-to-carbon abundance ratio of 2.
Fromm, Steffanie; Senkler, Jennifer; Eubel, Holger; Peterhänsel, Christoph; Braun, Hans-Peter
2016-05-01
The mitochondrial NADH dehydrogenase complex (complex I) is of particular importance for the respiratory chain in mitochondria. It is the major electron entry site for the mitochondrial electron transport chain (mETC) and therefore of great significance for mitochondrial ATP generation. We recently described an Arabidopsis thaliana double-mutant lacking the genes encoding the carbonic anhydrases CA1 and CA2, which both form part of a plant-specific 'carbonic anhydrase domain' of mitochondrial complex I. The mutant lacks complex I completely. Here we report extended analyses for systematically characterizing the proteome of the ca1ca2 mutant. Using various proteomic tools, we show that lack of complex I causes reorganization of the cellular respiration system. Reduced electron entry into the respiratory chain at the first segment of the mETC leads to induction of complexes II and IV as well as alternative oxidase. Increased electron entry at later segments of the mETC requires an increase in oxidation of organic substrates. This is reflected by higher abundance of proteins involved in glycolysis, the tricarboxylic acid cycle and branched-chain amino acid catabolism. Proteins involved in the light reaction of photosynthesis, the Calvin cycle, tetrapyrrole biosynthesis, and photorespiration are clearly reduced, contributing to the significant delay in growth and development of the double-mutant. Finally, enzymes involved in defense against reactive oxygen species and stress symptoms are much induced. These together with previously reported insights into the function of plant complex I, which were obtained by analysing other complex I mutants, are integrated in order to comprehensively describe 'life without complex I'.
Performance evaluation of the Sysmex XS-1000i automated haematology analyser.
Ghys, T; Malfait, R; VAN den Bossche, J
2009-10-01
The Sysmex XS-1000i is a compact new, fully automated haematology analyser, designed to generate complete blood counts with five-part leucocyte differential. In our study, a Sysmex XS-1000i instrument was evaluated according to Clinical Laboratory Standards Institute (CLSI) and International Council for Standardization in Haematology (ICSH) guidelines. Precision, carry-over and linearity were determined. Using a total of 700 patient samples, results from the Sysmex XS-1000i were compared with those from a Sysmex XE-2100, an Abbott Cell Dyn 4000 and the manual reference leucocyte differential. Using quality control material, total and within-run imprecision was less than 3% except for platelets. The system demonstrated good linearity over the entire reporting range and no carry-over (XS-1000i showed good correlation with XE-2100, CD-4000 and the manual reference leucocyte differential. Overall flagging sensitivity and specificity were 91% and 48%, respectively. In conclusion, the Sysmex XS-1000i demonstrated good analytical performance, is able to generate a complete blood count with five-part differential on low blood volumes and has considerable back-up capacity.
Grafakos, Loukas
2014-01-01
The main goal of this text is to present the theoretical foundation of the field of Fourier analysis on Euclidean spaces. It covers classical topics such as interpolation, Fourier series, the Fourier transform, maximal functions, singular integrals, and Littlewood–Paley theory. The primary readership is intended to be graduate students in mathematics with the prerequisite including satisfactory completion of courses in real and complex variables. The coverage of topics and exposition style are designed to leave no gaps in understanding and stimulate further study. This third edition includes new Sections 3.5, 4.4, 4.5 as well as a new chapter on “Weighted Inequalities,” which has been moved from GTM 250, 2nd Edition. Appendices I and B.9 are also new to this edition. Countless corrections and improvements have been made to the material from the second edition. Additions and improvements include: more examples and applications, new and more relevant hints for the existing exercises, new exercises, and...
Molecular and phylogenetic analyses suggest an additional hepatitis B virus genotype "I".
Directory of Open Access Journals (Sweden)
Hai Yu
Full Text Available A novel hepatitis B virus (HBV strain (W29 was isolated from serum samples in the northwest of China. Phylogenetic and distance analyses indicate that this strain is grouped with a series of distinct strains discovered in Vietnam and Laos that have been proposed to be a new genotype I. TreeOrderScan and GroupScan methods were used to study the intergenotype recombination of this special group. Recombination plots and tree maps of W29 and these putative genotype I strains exhibit distinct characteristics that are unexpected in typical genotype C strains of HBV. The amino acids of P gene, S gene, X gene, and C gene of all genotypes (including subtypes were compared, and eight unique sites were found in genotype I. In vitro and in vivo experiments were also conducted to determine phenotypic characteristics between W29 and other representative strains of different genotypes obtained from China. Secretion of HBsAg in Huh7 cells is uniformly abundant among genotypes A, B, C, and I (W29, but not genotype D. HBeAg secretion is low in genotype I (W29, whose level is close to genotype A and much lower than genotypes B, C, and D. Results from the acute hydrodynamic injection mouse model also exhibit a similar pattern. From an overview of the results, the viral markers of W29 (I1 in Huh7 cells and mice had a more similar level to genotype A than genotype C, although the latter was closer to W29 in distance analysis. All evidence suggests that W29, together with other related strains found in Vietnam and Laos, should be classified into a new genotype.
Two Fourier analyses on the Cantor set
Gatesoupe, M; Salinger, DL
1998-01-01
The classical Cantor set is given the structure of a compact Abelian group in two ways: the Cantor group and the group of dyadic integers. The relations between the trigonometric series with respect to the two structures are studied, specifically for radial functions and for spherical functions. (C)
Directory of Open Access Journals (Sweden)
O. Demir
2016-01-01
Full Text Available In this study, to investigate and understand the nature of fracture behavior properly under in-plane mixed mode (Mode-I/II loading, three-dimensional fracture analyses and experiments of compact tension shear (CTS specimen are performed under different mixed mode loading conditions. Al 7075-T651 aluminum machined from rolled plates in the L-T rolling direction (crack plane is perpendicular to the rolling direction is used in this study. Results from finite element analyses and fracture loads, crack deflection angles obtained from the experiments are presented. To simulate the real conditions in the experiments, contacts are defined between the contact surfaces of the loading devices, specimen and loading pins. Modeling, meshing and the solution of the problem involving the whole assembly, i.e., loading devices, pins and the specimen, with contact mechanics are performed using ANSYSTM. Then, CTS specimen is analyzed separately using a submodeling approach, in which three-dimensional enriched finite elements are used in FRAC3D solver to calculate the resulting stress intensity factors along the crack front. Having performed the detailed computational and experimental studies on the CTS specimen, a new specimen type together with its loading device is also proposed that has smaller dimensions compared to the regular CTS specimen. Experimental results for the new specimen are also presented.
Energy Technology Data Exchange (ETDEWEB)
Schirm, Maximilien R. P.; Wilson, Christine D.; Parkin, Tara J. [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Kamenetzky, Julia; Glenn, Jason; Rangwala, Naseem [Center for Astrophysics and Space Astronomy, 389-UCB, University of Colorado, Boulder, CO 80303 (United States); Spinoglio, Luigi; Pereira-Santaella, Miguel [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Baes, Maarten; De Looze, Ilse [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Barlow, Michael J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Clements, Dave L. [Astrophysics Group, Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Karczewski, Oskar Ł. [Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Madden, Suzanne C.; Rémy-Ruyer, Aurélie; Wu, Ronin, E-mail: schirmmr@mcmaster.ca, E-mail: wilson@physics.mcmaster.ca [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France)
2014-02-01
We present Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) observations of the Antennae (NGC 4038/39), a well-studied, nearby (22 Mpc), ongoing merger between two gas-rich spiral galaxies. The SPIRE-FTS is a low spatial ( FWHM ∼ 19''-43'') and spectral (∼1.2 GHz) resolution mapping spectrometer covering a large spectral range (194-671 μm, 450-1545 GHz). We detect five CO transitions (J = 4-3 to J = 8-7), both [C I] transitions, and the [N II] 205 μm transition across the entire system, which we supplement with ground-based observations of the CO J = 1-0, J = 2-1, and J = 3-2 transitions and Herschel Photodetecting Array Camera and Spectrometer (PACS) observations of [C II] and [O I] 63 μm. Using the CO and [C I] transitions, we perform both a local thermodynamic equilibrium (LTE) analysis of [C I] and a non-LTE radiative transfer analysis of CO and [C I] using the radiative transfer code RADEX along with a Bayesian likelihood analysis. We find that there are two components to the molecular gas: a cold (T {sub kin} ∼ 10-30 K) and a warm (T {sub kin} ≳ 100 K) component. By comparing the warm gas mass to previously observed values, we determine a CO abundance in the warm gas of x {sub CO} ∼ 5 × 10{sup –5}. If the CO abundance is the same in the warm and cold gas phases, this abundance corresponds to a CO J = 1-0 luminosity-to-mass conversion factor of α{sub CO} ∼ 7 M {sub ☉} pc{sup –2} (K km s{sup –1}){sup –1} in the cold component, similar to the value for normal spiral galaxies. We estimate the cooling from H{sub 2}, [C II], CO, and [O I] 63 μm to be ∼0.01 L {sub ☉}/M {sub ☉}. We compare photon-dominated region models to the ratio of the flux of various CO transitions, along with the ratio of the CO flux to the far-infrared flux in NGC 4038, NGC 4039, and the overlap region. We find that the densities recovered from our non-LTE analysis are consistent with a
DUT som didaktisk felt – en empirisk analyse af didaktiske temaer i perioden 2006-2013
Directory of Open Access Journals (Sweden)
Tina Bering Keiding
2016-04-01
Full Text Available Artiklen foretager en systematisk kategorisering og analyse af de bidrag, som har været bragt i Dansk Universitetspædagogisk Tidsskrift (DUT fra 2006-2013. Formålet er at undersøge, hvilke didaktiske temaer tidsskriftet har været optaget af og at diskutere mulige implikationer for universitetspædagogikkens funktion i forhold til at bidrage til undervisernes didaktiske viden. Analysen viser, at bidragene altovervejende er optaget af metodespørgsmål, og inden for denne kategori stort set udelukkende har beskæftiget sig med handlingsorienterede og/eller dialogiske undervisningsformer. The paper presents a systematic categorization of 115 papers published in the Danish Journal for Teaching and Learning in Higher Education (DUT from 2006 to 2013. The aim is to explore which didactic topics the journal deals with and how it contributes to Danish research into teaching and learning. The categorization shows that most of the contributions deal with teaching methods. A subsequent analysis shows that the contributions almost exclusively address active and social teaching methods (teaching as experience and teaching as interaction.
DUT som didaktisk felt – en empirisk analyse af didaktiske temaer i perioden 2006-2013
Directory of Open Access Journals (Sweden)
Ane Qvortrup
2015-08-01
Full Text Available Artiklen foretager en systematisk kategorisering og analyse af de bidrag, som har været bragt i Dansk Universitetspædagogisk Tidsskrift (DUT fra 2006-2013. Formålet er at undersøge, hvilke didaktiske temaer tidsskriftet har været optaget af og at diskutere mulige implikationer for universitetspædagogikkens funktion i forhold til at bidrage til undervisernes didaktiske viden. Analysen viser, at bidragene altovervejende er optaget af metodespørgsmål, og inden for denne kategori stort set udelukkende har beskæftiget sig med handlingsorienterede og/eller dialogiske undervisningsformer. The paper presents a systematic categorization of 115 papers published in the Danish Journal for Teaching and Learning in Higher Education (DUT from 2006 to 2013. The aim is to explore which didactic topics the journal deals with and how it contributes to Danish research into teaching and learning. The categorization shows that most of the contributions deal with teaching methods. A subsequent analysis shows that the contributions almost exclusively address active and social teaching methods (teaching as experience and teaching as interaction.
Pethick, James; Patel, Prashanth; Davies, Timothy; Thompson, John; Nallagonda, Madhavi; Beech, Alison; Collinson, Paul; Lee, Virginia; Gupta, Pankaj
2016-11-01
Background The measurement of cardiac troponin is central for the diagnosis of myocardial infarction (MI). It is recommended that a coefficient of variation of ≤10% is achieved at the diagnostic threshold and significant change between serial measurements reported. Many modern laboratories use multiple analysers linked by automation where samples are randomly assigned to an analyser. It is therefore important to consider the combined effect of all analysers on the analytical performance of troponin measurement. Method The performance of a contemporary troponin-I (cTn-I) assay run on three analysers, linked by an automated track, was undertaken across a range of cTn-I concentrations. The data for the three analysers were aggregated to obtain the combined analytical coefficient of variation (CVA) and reference change values (RCVs). Results The CVA improved with increasing concentration and calculated RCVs ranged from 67.2% (±13 ng/L) to 32% (±160 ng/L) between cTn-I values 20 ng/L and 500 ng/L. Although there were significant differences in cTn-I measurement between analysers around the diagnostic threshold ( P diagnosis of MI. We also show that the RCV varies according to baseline cTn-I values and that reporting a single RCV across the analytical range of cTn-I may not be appropriate.
Transformadas Discretas de Fourier
Alpízar-Brenes, Geisel; Calderón-Arce, Cindy; Soto-Quirós, Juan Pablo
2015-01-01
Proyecto de Investigación (VIE-5402-1440-4301). Este proyecto presenta un marco matem atico-computacional para el desarrollo de un conjunto de de niciones derivadas de la transformada discreta de Fourier (TDF), que son la funci on discreta de ambig uedad, la transformada discreta de Zak, la transformada discreta de Fourier en tiempo corto, la transformada discreta chirp-Fourier, la transformada discreta de Fourier de quaterniones, la transformada discreta de Cohen, la transform...
Energy Technology Data Exchange (ETDEWEB)
Chen, Yen-Shu, E-mail: yschen@iner.org.t [Nuclear Engineering Division, Institute of Nuclear Energy Research, 1000, Wenhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546, Taiwan (China); Yuann, Yng-Ruey; Dai, Liang-Che; Lin, Yon-Pon [Nuclear Engineering Division, Institute of Nuclear Energy Research, 1000, Wenhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546, Taiwan (China)
2011-05-15
Research highlights: The Chinshan Mark I containment pressure-temperature responses are analyzed. GOTHIC is used to calculate the containment responses under three pipe break events. This study is used to support the Chinshan Stretch Power Uprate (SPU) program. The calculated peak pressure and temperature are still below the design values. The Chinshan containment integrity can be maintained under SPU condition. - Abstract: Chinshan Nuclear Power Plant in Taiwan is a GE-designed twin-unit BWR/4 plant with original licensed thermal power (OLTP) of 1775 MWt for each unit. Recently, the Stretch Power Uprate (SPU) program for the Chinshan plant is being conducted to uprate the core thermal power to 1858 MWt (104.66% OLTP). In this study, the Chinshan Mark I containment pressure/temperature responses during LOCA at 105% OLTP (104.66% OLTP + 0.34% OLTP power uncertainty = 105% OLTP) are analyzed using the containment thermal-hydraulic program GOTHIC. Three kinds of LOCA (Loss of Coolant Accident) scenarios are investigated: Recirculation Line Break (RCLB), Main Steam Line Break (MSLB), and Feedwater Line Break (FWLB). In the short-term analyses, blowdown data generated by RELAP5 transient analyses are provided as boundary conditions to the GOTHIC containment model. The calculated peak drywell pressure and temperature in the RCLB event are 217.2 kPaG and 137.1 {sup o}C, respectively, which are close to the original FSAR results (219.2 kPaG and 138.4 {sup o}C). Additionally, the peak drywell temperature of 155.3 {sup o}C calculated by MSLB is presented in this study. To obtain the peak suppression pool temperature, a long-term RCLB analysis is performed using a simplified RPV (Reactor Pressure Vessel) volume to calculate blowdown flow rate. One RHR (Residual Heat Removal) heat exchanger is assumed to be inoperable for suppression pool cooling mode. The calculated peak suppression pool temperature is 93.2 {sup o}C, which is below the pool temperature used for evaluating the
A Borderline Random Fourier Series
Talagrand, Michel
1995-01-01
Consider a mean zero random variable $X$, and an independent sequence $(X_n)$ distributed like $X$. We show that the random Fourier series $\\sum_{n\\geq 1} n^{-1} X_n \\exp(2i\\pi nt)$ converges uniformly almost surely if and only if $E(|X|\\log\\log(\\max(e^e, |X|))) < \\infty$.
Borer, J
1977-01-01
Runs 800, 813, 842 and physics runs from 18.1.77 to 21.5.77, Development of a new set-up for working line measurements including a Fast Fourier Transform Spectrum Analyser and using weak beam excitiation with broad-band noise
Principles of Fourier analysis
Howell, Kenneth B
2001-01-01
Fourier analysis is one of the most useful and widely employed sets of tools for the engineer, the scientist, and the applied mathematician. As such, students and practitioners in these disciplines need a practical and mathematically solid introduction to its principles. They need straightforward verifications of its results and formulas, and they need clear indications of the limitations of those results and formulas.Principles of Fourier Analysis furnishes all this and more. It provides a comprehensive overview of the mathematical theory of Fourier analysis, including the development of Fourier series, "classical" Fourier transforms, generalized Fourier transforms and analysis, and the discrete theory. Much of the author''s development is strikingly different from typical presentations. His approach to defining the classical Fourier transform results in a much cleaner, more coherent theory that leads naturally to a starting point for the generalized theory. He also introduces a new generalized theory based ...
Glomsrød, Jannicke Storm
2007-01-01
Hvilke roller og funksjoner innehar Kilgore Trout-karakteren i Kurt Vonneguts forfatterskap? Hvilken betydning har han og hva ligger til grunn for denne gjennomgangsfigurens ankomst og endelige avgang i litteraturen? I denne oppgaven søker jeg å undersøke og finne svaret på disse spørsmålene. Kilgore Trout går igjen i syv av Vonneguts fjorten romaner og er en gjennomgangsfigur i drøye 32 år av dennes forfatterskap, som strekker seg over 53 år med Player Piano fra 1952 i den ene enden og A ...
DEFF Research Database (Denmark)
Jørgensen, Mårten Flø; Murray, Shauna; Daugbjerg, Niels
2004-01-01
, and origin of the sulcus. The description of A. elegans by Grell and Wohlfarth-Bottermann was found to be identical to it. A species fitting the original description of A. operculatum was cultured and included in the analyses. Based on cladistic and molecular analyses, it grouped together with all other...
Energy Technology Data Exchange (ETDEWEB)
Bruni, S.; Guglielmi, V. [Universita degli Studi di Milano, Dipartimento di Chimica Inorganica, Metallorganica e Analitica, Milano (Italy); Caglio, S. [Dipartimento di analisi scientifiche, Open Care, Milano (Italy); Poldi, G. [Dipartimento di analisi scientifiche, Open Care, Milano (Italy); LAM, Universita degli Studi di Bergamo, Bergamo (Italy)
2008-07-15
Some art objects being small and very precious prevents conservators and conservation scientists from whatever kind of sampling, so that only completely non-invasive (n.i.) studies are permitted. Besides, also moving the object is sometimes forbidden: this happens for jewels as well as for manuscripts, illuminated codices, drawings and paintings. Some important physical n.i. analyses, such as PIXE and PIGE, therefore cannot be used in many cases. With these limitations, only imaging techniques in X, UV, Visible and IR bands, and a few spectroscopic methods that can be carried out with portable instruments can be applied, i.e. molecular spectroscopies like Fourier transform infrared (FTIR), Raman, UV visible and near IR reflectance spectrometry (UV-Vis-NIR RS) and atomic spectroscopy like energy dispersive X-ray fluorescence (EDXRF). The use of only one or two of these techniques is usually far from giving all the information required to achieve a full characterization of materials used by the artist or during restorations, and to understand some conservative problems of the object. On the contrary, a joined use of n.i. analyses can supply a larger set of data, allowing for cross checks. With this aim we show a fully integrated spectroscopic approach to polychrome objects, and, in particular, to drawings and illuminated manuscripts, using portable instruments, specifically {mu}-FTIR, {mu}-Raman, Vis-RS and EDXRF, where also the Raman signal does not suffer fluorescence caused by varnish coating and from binder. We propose the joined use of all these four physical analyses to characterize materials - support, pigments, dyes, binders, etc. - on a complex case: a painted and drawn parchment of the late 15th century, or the beginning of the 16th, partly attributed to Andrea Mantegna. The collected spectroscopic data have been compared to proper spectral databases, some of which specifically realized in our laboratories. Also, mixtures of pigments and their
Fourier transformation for pedestrians
Butz, Tilman
2006-01-01
Meant to serve an "entertaining textbook," this book belongs to a rare genre. It is written for all students and practitioners who deal with Fourier transformation. Fourier series as well as continuous and discrete Fourier transformation are covered, and particular emphasis is placed on window functions. Many illustrations and easy-to-solve exercises make the book especially accessible, and its humorous style will add to the pleasure of learning from it.
Fourier Series Operating Package
Charnow, Milton L.
1961-01-01
This report presents a computer program for multiplying, adding, differentiating, integrating, "barring" and scalarly multiplying "literal" Fourier series as such, and for extracting the coefficients of specified terms.
Szu, Harold H.
1999-03-01
The early vision principle of redundancy reduction of 108 sensor excitations is understandable from computer vision viewpoint toward sparse edge maps. It is only recently derived using a truly unsupervised learning paradigm of artificial neural networks (ANN). In fact, the biological vision, Hubel- Wiesel edge maps, is reproduced seeking the underlying independent components analyses (ICA) among 102 image samples by maximizing the ANN output entropy (partial)H(V)/(partial)[W] equals (partial)[W]/(partial)t. When a pair of newborn eyes or ears meet the bustling and hustling world without supervision, they seek ICA by comparing 2 sensory measurements (x1(t), x2(t))T equalsV X(t). Assuming a linear and instantaneous mixture model of the external world X(t) equals [A] S(t), where both the mixing matrix ([A] equalsV [a1, a2] of ICA vectors and the source percentages (s1(t), s2(t))T equalsV S(t) are unknown, we seek the independent sources approximately equals [I] where the approximated sign indicates that higher order statistics (HOS) may not be trivial. Without a teacher, the ANN weight matrix [W] equalsV [w1, w2] adjusts the outputs V(t) equals tanh([W]X(t)) approximately equals [W]X(t) until no desired outputs except the (Gaussian) 'garbage' (neither YES '1' nor NO '-1' but at linear may-be range 'origin 0') defined by Gaussian covariance G equals [I] equals [W][A] learning. Consequently, rather using the faithful but dumb computer: 'GARBAGE-IN, GARBAGE-OUT,' the smarter neurocomputer will be equipped with an unsupervised learning that extracts 'RAW INFO-IN, (until) GARBAGE-OUT' for sensory knowledge acquisition in enhancing Machine IQ. We must go beyond the LMS error energy, and apply HOS To ANN. We begin with the Auto- Regression (AR) which extrapolates from the past X(t) to the future ui(t+1) equals wiTX(t) by varying the weight vector in minimizing LMS error energy E equals at the fixed point (partial)E/(partial)wi equals 0 resulted in an exact Toplitz matrix
Øvrebotten, Kristian
2015-01-01
Sidan oljekrisa på 1970-talet som førte til ein gradvis overgang frå bruk av oljekjelar og parafinkaminar til panelomnar og varmepumper, har andelen elektrisitet stadig auka mens andelen av olje har vore redusert. Andelen av elektrisitet hos hushalda utgjer i dag om lag 79 % av den samla energibruken hos hushalda i Noreg. Dette høge forbruket av elektrisitet hos hushalda bidreg til å skape problem med høge effekttoppar i kraftnettet som igjen skapar problem for kraftdistributørar og er med...
Energy Technology Data Exchange (ETDEWEB)
Ortmann, L.F.; Dunford, R.; McHenry, K.; Hausmann, E.
1985-01-01
A standardized radiographic series of incrementally increasing alveolar crestal defects in skulls were subjected to analyses by subtraction radiography and computer assisted quantitative densitometric analysis. Subjects were able to detect change using subtraction radiography in alveolar bone defects with bone loss in the range of 1-5 percent as measured by /sup 125/I absorptiometry. Quantitative densitometric analyses utilizing radiographic pairs adjusted for differences in contrast (gamma corrected) can be used to follow longitudinal changes at a particular alveolar bone site. Such measurements correlate with change observed by /sup 125/I absorptiometry (r=0.82-0.94). (author).
Performance evaluation of the Abbott CELL-DYN Ruby and the Sysmex XT-2000i haematology analysers.
Leers, M P G; Goertz, H; Feller, A; Hoffmann, J J M L
2011-02-01
Two mid-range haematology analysers (Abbott CELL-DYN Ruby and Sysmex XT-2000i) were evaluated to determine their analytical performance and workflow efficiency in the haematology laboratory. In total 418 samples were processed for determining equivalence of complete blood count (CBC) measurements, and 100 for reticulocyte comparison. Blood smears served for assessing the agreement of the differential counts. Inter-instrument agreement for most parameters was good although small numbers of discrepancies were observed. Systematic biases were found for mean cell volume, reticulocytes, platelets and mean platelet volume. CELL-DYN Ruby WBC differentials were obtained with all samples while the XT-2000i suppressed differentials partially or completely in 13 samples (3.1%). WBC subpopulation counts were otherwise in good agreement with no major outliers. Following first-pass CBC/differential analysis, 88 (21%) of XT-2000i samples required further analyser processing compared to 18 (4.3%) for the CELL-DYN Ruby. Smear referrals for suspected WBC/nucleated red blood cells and platelet abnormalities were indicated for 106 (25.4%) and 95 (22.7%) of the XT-2000i and CELL-DYN Ruby samples respectively. Flagging efficiencies for both analysers were found to be similar. The Sysmex XT-2000i and Abbott CELL-DYN Ruby analysers have broadly comparable analytical performance, but the CELL-DYN Ruby showed superior first-pass efficiency. © 2010 Blackwell Publishing Ltd.
Transcriptomics analyses reveal global roles of the regulator AveI in Streptomyces avermitilis.
Chen, Lei; Chen, Jun; Jiang, Yuqian; Zhang, Weiwen; Jiang, Weihong; Lu, Yinhua
2009-09-01
In our previous studies, AveI was identified as a negative regulator for avermectin biosynthesis in Streptomyces avermitilis NRRL8165, and the aveI-null mutant of NRRL8165 could produce at least 10-fold more avermectin B1a than its wild-type strain. In order to explore the regulatory mechanism by which aveI affects avermectin biosynthesis, in this study, we performed a global comparative gene expression analysis between aveI deletion mutant 8165DeltaI and its wild-type strain using NimbleGen microarrays in combination with real-time reverse transcriptase-PCR. The results showed the aveI deletion has caused global changes beyond the avermectin biosynthetic gene cluster. The aveI gene not only negatively affected expression of the avermectin biosynthetic gene cluster but also affected expression of oligomycin and filipin biosynthetic clusters. In addition, the genes involved in precursor biosyntheses for avermectin or other antibiotics, such as crotonyl-CoA reductase and methylmalonyl-CoA decarboxylase, were also upregulated in aveI mutant. Furthermore, genes in several key primary metabolic pathways, such as protein synthesis and fatty acid metabolism, were found downregulated in the mutant. These results suggested that the aveI gene may be functioning as a global regulator involved in directing carbon flux from primary to secondary metabolism.
Analyse av klimatilpasningstiltak : en casestudie av overvannsnettet på Bogafjell i Sandnes kommune
Bekkum, Ina
2012-01-01
For å simulere klimaendringenes effekt på avløpssystemet og klimatilpasningstiltakenes avbøtende virkning kan man benyttes seg av urbanhydrologiske avløpsmodeller. I denne oppgaven er det gjennomført et casestudie av overvannsnettet på Bogafjell i Sandnes kommune. Det er gjort simuleringer av enkeltregn i form av symmetriske nedbørshyetogram, med og uten klimatillegg – i Rosie/ArcGIS med MOUSE beregningsmotor – for å teste tiltaksprinsipper som frakopling av overvann, fordrøyning av ...
Sterken, C.
2003-03-01
This paper gives a short account of some key elements in the life of Jean Baptiste Joseph Fourier (1768-1830), specifically his relation to Napoleon Bonaparte. The mathematical approach to Fourier series and the original scepticism by French mathematicians are briefly illustrated.
Generalized Fourier transforms classes
DEFF Research Database (Denmark)
Berntsen, Svend; Møller, Steen
2002-01-01
The Fourier class of integral transforms with kernels $B(\\omega r)$ has by definition inverse transforms with kernel $B(-\\omega r)$. The space of such transforms is explicitly constructed. A slightly more general class of generalized Fourier transforms are introduced. From the general theory...
Fourier Series Optimization Opportunity
Winkel, Brian
2008-01-01
This note discusses the introduction of Fourier series as an immediate application of optimization of a function of more than one variable. Specifically, it is shown how the study of Fourier series can be motivated to enrich a multivariable calculus class. This is done through discovery learning and use of technology wherein students build the…
Evolution of heterogeneity (I2) estimates and their 95% confidence intervals in large meta-analyses
DEFF Research Database (Denmark)
Thorlund, Kristian; Imberger, Georgina; Johnston, Bradley C
2012-01-01
by sampling error. Recent studies have raised concerns about the reliability of I(2) estimates, due to their dependence on the precision of included trials and time-dependent biases. Authors have also advocated use of 95% confidence intervals (CIs) to express the uncertainty associated with I(2) estimates...
Conformational stability analyses of alpha subunit I domain of LFA-1 and Mac-1.
Directory of Open Access Journals (Sweden)
Debin Mao
Full Text Available β₂ integrin of lymphocyte function-associated antigen-1 (LFA-1 or macrophage-1 antigen (Mac-1 binds to their common ligand of intercellular adhesion molecule-1 (ICAM-1 and mediates leukocyte-endothelial cell (EC adhesions in inflammation cascade. Although the two integrins are known to have distinct functions, the corresponding micro-structural bases remain unclear. Here (steered-molecular dynamics simulations were employed to elucidate the conformational stability of α subunit I domains of LFA-1 and Mac-1 in different affinity states and relevant I domain-ICAM-1 interaction features. Compared with low affinity (LA Mac-1, the LA LFA-1 I domain was unstable in the presence or absence of ICAM-1 ligand, stemming from diverse orientations of its α₇-helix with different motifs of zipper-like hydrophobic junction between α₁- and α₇-helices. Meanwhile, spontaneous transition of LFA-1 I domain from LA state to intermediate affinity (IA state was first visualized. All the LA, IA, and high affinity (HA states of LFA-1 I domain and HA Mac-1 I domain were able to bind to ICAM-1 ligand effectively, while LA Mac-1 I domain was unfavorable for binding ligand presumably due to the specific orientation of S144 side-chain that capped the MIDAS ion. These results furthered our understanding in correlating the structural bases with their functions of LFA-1 and Mac-1 integrins from the viewpoint of I domain conformational stability and of the characteristics of I domain-ICAM-1 interactions.
Wolf, J.
2002-01-01
To analyse the effects of climate change on potato growth and production, both a simple growth model, POTATOS, and a comprehensive model, NPOTATO, were applied. Both models were calibrated and tested against results from experiments and variety trials in The Netherlands. The sensitivity of model
From "Dirac combs" to Fourier-positivity
Giraud, Bertrand G
2015-01-01
Motivated by various problems in physics and applied mathematics, we look for constraints and properties of real Fourier-positive functions, i.e. with positive Fourier transforms. Properties of the "Dirac comb" distribution and of its tensor products in higher dimensions lead to Poisson resummation, allowing for a useful approximation formula of a Fourier transform in terms of a limited number of terms. A connection with the Bochner theorem on positive definiteness of Fourier-positive functions is discussed. As a practical application, we find simple and rapid analytic algorithms for checking Fourier-positivity in 1- and (radial) 2-dimensions among a large variety of real positive functions. This may provide a step towards a classification of positive positive-definite functions.
Discriminating among degenerative parkinsonisms using advanced 123I-ioflupane SPECT analyses
Directory of Open Access Journals (Sweden)
Simon Badoud
2016-01-01
PD, MSA, PSP and CBD have distinct patterns of dopaminergic depletion on 123I-ioflupane SPECT. The high specificity of 84–90% for PD versus APS indicates that the classifier is particularly useful for confirming APS cases.
A tale of two fjords – en analyse af bundfauna samfund i Odense og Roskilde Fjord
DEFF Research Database (Denmark)
Banta, Gary Thomas; Delefosse, Matthieu; Canal Vergés, Paula;
var dyndsnegle (Hydrobia sp.) og små orme (polychaeter og oligochaeter) mens biomassen var domineret af muslinger, især sandmuslingen (Mya arenaria). Der var betydelig variation i sammensætningen af de bentiske samfund på alle undersøgte rumlige skalaer. F.eks. var der ca. 38% forskel målt vha Bray...... gravende muslinger (f.eks. Cerastoderma spp.) mens Odense Fjord (OF) havde flere orme. Ligeledes så vi mange tubificide orme i den indre del af OF. I den indre del af RF så vi i stedet mange dansemyggelarver (Chironomidae). Af de undersøgte miljøvariable var vanddybde og salinitet (både niveauet og...
Damiani, A M; Jang, H K; Matsumura, T; Yokoyama, N; Miyazawa, T; Mikami, T
1999-01-01
To map the transcripts encoding the equine herpesvirus type 4 (EHV-4) glycoproteins I (gI) and E (gE), transcriptional analyses were performed at the right part of the unique short segment of EHV-4 genome. The results revealed that the gI gene is encoded by a 1.6-kb transcript which is 3' coterminal with a 3.0-kb gD mRNA while the gE gene is encoded by two transcripts of 3.5- and 2.4-kb in size. The transcriptional patterns described in this study for the EHV-4 gI and gE are similar to those found in the equivalent region of herpes simplex virus type 1 and feline herpesvirus type 1. Characterization of EHV-4 gI and gE glycoprotein genes may facilitate future studies to define their roles in the EHV-4 infection.
Fourier analysis an introduction
Stein, Elias M
2003-01-01
This first volume, a three-part introduction to the subject, is intended for students with a beginning knowledge of mathematical analysis who are motivated to discover the ideas that shape Fourier analysis. It begins with the simple conviction that Fourier arrived at in the early nineteenth century when studying problems in the physical sciences--that an arbitrary function can be written as an infinite sum of the most basic trigonometric functions.The first part implements this idea in terms of notions of convergence and summability of Fourier series, while highlighting applications such as th
Dakara, C; Hansen, S.; Wagenmann, M; Schipper, J; Werminghaus, P
2015-01-01
Einleitung: Mit zunehmender Verfügbarkeit von mobilen Applikationen für Smartphones eröffnen sich neue Wege zur Verbreitung medizinischer Inhalte. Daher untersuchten wir die gängigen App-Stores nach HNO-relevanten Begriffen um die mobilen Applikationen (mA) zu analysieren. Methoden: Im November 2014 wurden "Google Play Store" (GPS) und "iTunes Store" (iTS) auf HNO-relevante Suchbegriffe auf Deutsch durchsucht. Die mA wurden kategorisiert nach Thema, Bewertung, Anzahl der Bewertungen, Prei...
Fourier-Resolved Spectroscopy of AGN using XMM-Newton data: I. The 3-10 keV band results
Papadakis, I E; Kazanas, D
2007-01-01
We present the results from the Fourier Resolved Spectroscopy of archival XMM-Newton data of five AGN, namely, Mrk 766, NGC 3516, NGC 3783, NGC 4051 and Ark 564. This work supplements the earlier study of MCG-6-30-15 as well as those of several Galactic Black Hole Candidate sources. Our results exhibit much larger diversity than those of Galactic sources, a fact we attribute to the diversity of their masses. When we take into account this effect and combine our results with those from Cyg X-1, it seems reasonable to conclude that, at high frequencies, the slope of the Fourier-resolved spectra in accreting black hole systems decreases with increasing frequency as proportional to f^{-0.25}, irrespective of whether the system is in its High or Low state. This result implies that the flux variations in AGN are accompanied by complex spectral slope variations as well. We also find that the Fe Ka line in Mrk 766, NGC 3783 and NGC 4051 is variable on time scales ~day - 1 hour. The iron fluorescence line is absent in...
2114 Vejledning til øvelser i uorganisk kvalitativ analyse og stofidentifikation
DEFF Research Database (Denmark)
Berg, Rolf W.
The instruction is a A-4 format book on inorganic analytical student experiments on reactions in aqueous solution. It covers about half of the elements in the periodic table, i.e. the most important ones : H, Li, B, C, N, O, Na, Mg, Al, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br...
DEFF Research Database (Denmark)
Berg, Rolf W.
1999-01-01
The instruction is a A-4 format book on inorganic analytical student experiments on reactions inaqueous solution. It covers about half of the elements in the periodic table, i.e. the mostimportant ones : H, Li, B, C, N, O, Na, Mg, Al, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br...
Debnath, Lokenath
2012-01-01
This article deals with a brief biographical sketch of Joseph Fourier, his first celebrated work on analytical theory of heat, his first great discovery of Fourier series and Fourier transforms. Included is a historical development of Fourier series and Fourier transforms with their properties, importance and applications. Special emphasis is made…
Fourier transformation for pedestrians
Butz, Tilman
2015-01-01
This book is an introduction to Fourier Transformation with a focus on signal analysis, based on the first edition. It is well suited for undergraduate students in physics, mathematics, electronic engineering as well as for scientists in research and development. It gives illustrations and recommendations when using existing Fourier programs and thus helps to avoid frustrations. Moreover, it is entertaining and you will learn a lot unconsciously. Fourier series as well as continuous and discrete Fourier transformation are discussed with particular emphasis on window functions. Filter effects of digital data processing are illustrated. Two new chapters are devoted to modern applications. The first deals with data streams and fractional delays and the second with the back-projection of filtered projections in tomography. There are many figures and mostly easy to solve exercises with solutions.
Digital Fourier analysis fundamentals
Kido, Ken'iti
2015-01-01
This textbook is a thorough, accessible introduction to digital Fourier analysis for undergraduate students in the sciences. Beginning with the principles of sine/cosine decomposition, the reader walks through the principles of discrete Fourier analysis before reaching the cornerstone of signal processing: the Fast Fourier Transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Fundamentals" includes practice problems and thorough Appendices for the advanced reader. As a special feature, the book includes interactive applets (available online) that mirror the illustrations. These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. For example, a real sine signal can be treated as a sum of clockwise and counter-clockwise rotating vectors. The applet illustration included with the book animates the rotating vectors and the resulting sine signal. By changing parameters such as amplitude and frequency, the reader ca...
Fourier transform mass spectrometry.
Scigelova, Michaela; Hornshaw, Martin; Giannakopulos, Anastassios; Makarov, Alexander
2011-07-01
This article provides an introduction to Fourier transform-based mass spectrometry. The key performance characteristics of Fourier transform-based mass spectrometry, mass accuracy and resolution, are presented in the view of how they impact the interpretation of measurements in proteomic applications. The theory and principles of operation of two types of mass analyzer, Fourier transform ion cyclotron resonance and Orbitrap, are described. Major benefits as well as limitations of Fourier transform-based mass spectrometry technology are discussed in the context of practical sample analysis, and illustrated with examples included as figures in this text and in the accompanying slide set. Comparisons highlighting the performance differences between the two mass analyzers are made where deemed useful in assisting the user with choosing the most appropriate technology for an application. Recent developments of these high-performing mass spectrometers are mentioned to provide a future outlook.
Knight, Norman F., Jr.; Phillips, Dawn R.; Raju, Ivatury S.
2008-01-01
The structural analyses described in the present report were performed in support of the NASA Engineering and Safety Center (NESC) Critical Initial Flaw Size (CIFS) assessment for the ARES I-X Upper Stage Simulator (USS) common shell segment. The structural analysis effort for the NESC assessment had three thrusts: shell buckling analyses, detailed stress analyses of the single-bolt joint test; and stress analyses of two-segment 10 degree-wedge models for the peak axial tensile running load. Elasto-plastic, large-deformation simulations were performed. Stress analysis results indicated that the stress levels were well below the material yield stress for the bounding axial tensile design load. This report also summarizes the analyses and results from parametric studies on modeling the shell-to-gusset weld, flange-surface mismatch, bolt preload, and washer-bearing-surface modeling. These analyses models were used to generate the stress levels specified for the fatigue crack growth assessment using the design load with a factor of safety.
The Swift Burst Analyser I: BAT and XRT spectral and flux evolution of Gamma Ray Bursts
Evans, P A; Osborne, J P; O'Brien, P T; Page, K L; Markwardt, C B; Barthelmy, S D; Beardmore, A P; Burrows, D N; Pagani, C; Starling, R L C; Romano, P
2010-01-01
Context: Gamma Ray Burst models predict the broadband spectral evolution and the temporal evolution of the energy flux. In contrast, standard data analysis tools and data repositories provide count-rate data, or use single flux conversion factors for all of the data, neglecting spectral evolution. Aims: To produce Swift BAT and XRT light curves in flux units, where the spectral evolution is accounted for. Methods: We have developed software to use the hardness ratio information to track spectral evolution of GRBs, and thus to convert the count-rate light curves from the BAT and XRT instruments on Swift into accurate, evolution-aware flux light curves. Results: The Swift Burst Analyser website (http://www.swift.ac.uk/burst_analyser) contains BAT, XRT and combined BAT-XRT flux light curves in three energy regimes for all GRBs observed by the Swift satellite. These light curves are automatically built and updated when data become available, are presented in graphical and plain-text format, and are available for ...
Generalized fiber Fourier optics.
Cincotti, Gabriella
2011-06-15
A twofold generalization of the optical schemes that perform the discrete Fourier transform (DFT) is given: new passive planar architectures are presented where the 2 × 2 3 dB couplers are replaced by M × M hybrids, reducing the number of required connections and phase shifters. Furthermore, the planar implementation of the discrete fractional Fourier transform (DFrFT) is also described, with a waveguide grating router (WGR) configuration and a properly modified slab coupler.
Directory of Open Access Journals (Sweden)
Trine Nesland
2014-11-01
Full Text Available Artikkelen handler om hvordan journalføringskriteriene «gjenstand for saksbehandling» og «verdi som dokumentasjon» er ment å skulle forstås, basert på hvordan kriteriene er omtalt og definert i eksisterende teori og litteratur.Artikkelen viser at det ikke eksisterer en omforent forståelse av kriterienes innhold, det vil si at kriteriene er tillagt ulik betydning i ulike tekster. Det har tegnet seg et bilde av at de relativt få tekstene som faktisk inneholder beskrivelser av journalføringskriteriene og begrepene kriteriene er bygget opp av, i hovedsak nærmer seg kriteriene enten på en dialektisk-relasjonell eller på en semiotisk-relasjonell måte, hvilket gir to tilsynelatende ulike tolkningsresultater. Det foreligger med andre ord en viss tolkningsmotstrid, hvilket nødvendigvis innebærer at det fortsatt er vanskelig å svare entydig på spørsmålet om hvordan journalføringskriteriene er ment å skulle forstås, og samtidig gir grunn til kritikk av det etablerte systemet.
Analyse af adfærd i idrætsfaciliteter
DEFF Research Database (Denmark)
Gade, Rikke; Christensen, Cecilie Breinholm; Krogh Jensen, Rasmus
2013-01-01
be optimised in accordance with the more individualised and varied practice of sports today. Tracking-technologies, such as RFID-technology and thermal video analysis, give the possibility to gain knowledge on the use of indoor sports facilities by tracking movements and positions of people in time and space......This article builds upon existing research at Department of Architecture, Design and Media Technology, Aalborg University. It deals with research based methods and technologies for analysing behaviour in sports facilities. There is a need to study how existing and new sports facilities can...... for improvements in terms of administration and design of sports facilities, as well as in sports training and coaching. On a research level, the methods and technologies presented in this article can be applied in further research of both the spatial and social aspects of sports and sports facilities....
Microstructural analyses of amorphic diamond, i-C, and amorphous carbon
DEFF Research Database (Denmark)
Collins, C. B.; Davanloo, F.; Jander, D.R.;
1992-01-01
Recent experiments have identified the microstructure of amorphic diamond with a model of packed nodules of amorphous diamond expected theoretically. However, this success has left in doubt the relationship of amorphic diamond to other noncrystalline forms of carbon. This work reports...... the comparative examinations of the microstructures of samples of amorphic diamond, i-C, and amorphous carbon. Four distinct morphologies were found that correlated closely with the energy densities used in preparing the different materials. Journal of Applied Physics is copyrighted by The American Institute...
Analyse av klimatilpassningstiltak : en casestudie av avløpsnettet i Veumdalen, Fredrikstad kommune
Myking, Jakob Severin Eide
2012-01-01
Økt forståelse av fortidens klimaendringer og klimasystemet i sin helhet, har gitt forskerne mulighet til å anta fremtidens klimaendringer. Denne økte forståelsen har gitt sikre tegn på at klimaendringene er knyttet til en stor grad av usikkerhet. Det eneste som er sikkert, er at klimaendringer kommer til å skje, og at det er umulig å si med sikkerhet når eller med hvilken kraft de vil inntreffe. Det som derimot kan sies med sikkerhet, er at befolkningen kommer til å øke. Dette vil føre til ø...
Correlliansk Wicca -En analyse av et nyreligiøst trossamfunn i vekst-
Johansen, Monica Frankrig
2015-01-01
Correlliansk wicca er en tradisjon innenfor wicca som baserer sin praksis på læren til High- Correll familien. Den correllianske wicca- tradisjonen ble grunnlagt av Caroline High- Correll. Correllianere anser seg selv for å være åpne for mange ulike livssyn og praksiser. De tror at det guddommelige kommer innenfra oss selv, og at religion eksisterer for å hjelpe oss til å finne det guddommelige i hver av oss, og ikke for å forsøke å erstatte denne guddommeligheten. Correllianere mener at alle...
Shmueli, U; Rabinovich, S; Weiss, G H
1989-06-01
An exact expression is derived for the conditional probability density function of a three-phase invariant and the general result is applied to the space group P1. The expression for the conditional density is given in terms of a sixfold Fourier series. A straightforward numerical evaluation of this series, without further analysis, is extremely time consuming. Much of the present paper is therefore devoted to an exposition of symmetries hidden in the various summations. The computational effort required for the evaluation of the above expression is thereby reduced to manageable proportions in a number of interesting cases. Results of numerical computations of the exact conditional density are given in the second paper in this series. It is also shown that the exact expression for the conditional probability reduces to that given by Cochran [Acta Cryst. (1955), 8, 473-478].
Tang, Xiao-Lin; Shi, Li
2011-10-04
This work mainly involved the investigation of the adsorption of thiophene on Cu(I)-supported HY-Al(2)O(3). It demonstrated a high sulfur capacity of 10 mg sulfur/g sorbent when the HY/Al(2)O(3) mass ratio was 3, loaded with 12% copper, calcined at 550 °C, and tested at ambient temperature. In situ Fourier transform infrared (FTIR) and temperature-programmed desorption (TPD) results indicated that the adsorption mechanisms on Cu(I)/HY-Al(2)O(3) primarily were π-complexation and sulfur-adsorbent (S-M; σ) bonds. Pyridine-FTIR showed the total weak Lewis acid contribution to the Cu(I)/HY-Al(2)O(3) adsorption desulfurization performance. © 2011 American Chemical Society
Guo, Jianping; Deng, Minjun; Lee, Seoung Soo; Wang, Fu; Li, Zhanqing; Zhai, Panmao; Liu, Huan; Lv, Weitao; Yao, Wen; Li, Xiaowen
2016-06-01
The radiative and microphysical effects of aerosols can affect the development of convective clouds. The objective of this study is to reveal if the overall aerosol effects have any discernible impact on the diurnal variations in precipitation and lightning by means of both observational analysis and modeling. As the first part of two companion studies, this paper is concerned with analyzing hourly PM10, precipitation, and lightning data collected during the summers of 2008-2012 in the Pearl River Delta region. Daily PM10 data were categorized as clean, medium, or polluted so that any differences in the diurnal variations in precipitation and lightning could be examined. Heavy precipitation and lightning were found to occur more frequently later in the day under polluted conditions than under clean conditions. Analyses of the diurnal variations in several meteorological factors such as air temperature, vertical velocity, and wind speed were also performed. They suggest that the influence of aerosol radiative and microphysical effects serve to suppress and enhance convective activities, respectively. Under heavy pollution conditions, the reduction in solar radiation reaching the surface delays the occurrence of strong convection and postpones heavy precipitation to late in the day when the aerosol invigoration effect more likely comes into play. Although the effect of aerosol particles can be discernible on the heavy precipitation through the daytime, the influence of concurrent atmospheric dynamics and thermodynamics cannot be ruled out.
Age-at-onset subsets of bipolar I disorders: A critical insight into admixture analyses.
Montlahuc, Claire; Curis, Emmanuel; Jonas, Sarah Flora; Bellivier, Frank; Chevret, Sylvie
2016-10-21
Gaussian mixture analysis is frequently used to model the age-at-onset (AAO) in bipolar I disorder and identify homogeneous subsets of patients. This study aimed to examine whether, using admixture analysis of AAO, cross-sectional designs (which cause right truncation), unreliable diagnosis for individuals younger than 10 years old (which causes left truncation) and the selection criterion used for admixture analysis impact the number of identified subsets. A simulation study was performed. Different criteria - the likelihood ratio test (LRT), the Akaike information criterion (AIC), and the Bayesian information criterion (BIC) - were compared using no, left and/or right truncation simulated data. The error rate of each criterion (percentage of erroneous number of detected subsets) was estimated. An application to two real databases, including 2,876 and 1,393 patients, is provided. Without data truncation and regardless of the distribution of AAO, the LRT and the AIC had much higher error rates (12% and 33%, respectively) than the BIC (1%). For a homogeneous population, the error rate increased with the introduction of left truncation. This study shows that the number of subsets identified using admixture analysis may depend on the sample size, the selection criterion, and the study design.
Fan, Jing; Chen, Chunxian; Yu, Qibin; Brlansky, Ronald H; Li, Zheng-Guo; Gmitter, Frederick G
2011-11-01
Citrus Huanglongbing (HLB) has been threatening citrus production worldwide. In this study, a comparative proteomic approach was applied to understand the pathogenic process of HLB in affected sweet orange leaves. Using the isobaric tags for relative and absolute quantification (iTRAQ) technique, we identified 686 unique proteins in the mature leaves of both mock-inoculated and diseased 'Madam Vinous' sweet orange plants. Of the identified proteins, 20 and 10 were differentially expressed in leaves with and without symptoms of HLB (fold change > 2.5), respectively, compared with mock-inoculated controls. Most significantly, upregulated proteins were involved in stress/defense response, such as four miraculin-like proteins, chitinase, Cu/Zn superoxide dismutase and lipoxygenase. Microarray analysis also showed that stress-related genes were significantly upregulated at the transcriptional level. For example, remarkable upregulations of miraculin-like proteins and Cu/Zn superoxide dismutase transcripts were observed. Moreover, the transcriptional patterns of miraculin-like protein 1 and Cu/Zn superoxide dismutase were examined at different stages of HLB disease development. Combined with the transcriptomic data, the proteomic data can provide an enhanced understanding of citrus stress/defense responses to HLB.
DEFF Research Database (Denmark)
Boolsen, Merete Watt
bogen forklarer de fundamentale trin i forskningsprocessen og applikerer dem på udvalgte kvalitative analyser: indholdsanalyse, Grounded Theory, argumentationsanalyse og diskursanalyse......bogen forklarer de fundamentale trin i forskningsprocessen og applikerer dem på udvalgte kvalitative analyser: indholdsanalyse, Grounded Theory, argumentationsanalyse og diskursanalyse...
Liflyand, E.
2012-01-01
We study an extension to Fourier transforms of the old problem on absolute convergence of the re-expansion in the sine (cosine) Fourier series of an absolutely convergent cosine (sine) Fourier series. The results are obtained by revealing certain relations between the Fourier transforms and their Hilbert transforms.
Rudin, Walter
2011-01-01
In the late 1950s, many of the more refined aspects of Fourier analysis were transferred from their original settings (the unit circle, the integers, the real line) to arbitrary locally compact abelian (LCA) groups. Rudin's book, published in 1962, was the first to give a systematic account of these developments and has come to be regarded as a classic in the field. The basic facts concerning Fourier analysis and the structure of LCA groups are proved in the opening chapters, in order to make the treatment relatively self-contained.
Association of HLA-DQA1 and -DQB1 alleles with type I diabetes in Arabs: a meta-analyses.
Hamzeh, A R; Nair, P; Al-Khaja, N; Al Ali, M T
2015-07-01
This study aimed at assessing the nature and significance of associations between various alleles of HLA-DQA1, HLA-DQB1, and type I diabetes (T1D) in Arab populations. Evidence from literature (published before 20 April 2015) was amassed and analysed through multiple meta-analyses, which yielded effect summary odds ratios and 95% confidence intervals for 24 alleles and 4 haplotypes. A total of 1273 cases and 1747 controls from 16 studies were analysed. High levels of significance were obtained to support higher T1D risk when harbouring DQA1*03:01. The alleles DQB1*02:01 and *03:02 and the haplotypes DR3 and DR4 were significant risk factors, albeit with high publication heterogeneity. The protective effects of DQA1*01:01, DQB1*05:03, *06:02, *06:03, and *06:04 were robustly suggested by all indicators of meta-analyses. The haplotypes DR7 and DR11 were strongly suggested to be protective in Arabs. A relatively small number of studies have emerged from Arab countries, mostly with inadequate power on an individual basis. This study fills the gap by providing significant size effect of human leukocyte antigen (HLA) alleles and completes the continuum of global ethnic differences in this context.
Fourier and Laplace Transforms
Beerends, R.J.; Morsche, ter H.G.; Berg, van den J.C.
2003-01-01
This textbook presents in a unified manner the fundamentals of both continuous and discrete versions of the Fourier and Laplace transforms. These transforms play an important role in the analysis of all kinds of physical phenomena. As a link between the various applications of these transforms the a
Introduction to Fourier Optics
Huggins, Elisha
2007-01-01
Much like a physical prism, which displays the frequency components of a light wave, Fourier analysis can be thought of as a mathematical prism that can tell us what harmonics or frequency components are contained in a recording of a sound wave. We wrote the MacScope II program so that the user could not only see a plot of the harmonic amplitudes…
Introduction to Fourier Optics
Huggins, Elisha
2007-01-01
Much like a physical prism, which displays the frequency components of a light wave, Fourier analysis can be thought of as a mathematical prism that can tell us what harmonics or frequency components are contained in a recording of a sound wave. We wrote the MacScope II program so that the user could not only see a plot of the harmonic amplitudes…
Bilinear Fourier restriction theorems
Demeter, Ciprian
2012-01-01
We provide a general scheme for proving $L^p$ estimates for certain bilinear Fourier restrictions outside the locally $L^2$ setting. As an application, we show how such estimates follow for the lacunary polygon. In contrast with prior approaches, our argument avoids any use of the Rubio de Francia Littlewood--Paley inequality.
Fast Fourier Orthogonalization
Ducas, L.; Prest, T.; Abramov, S.A.; Zima, E.V.; Gao, X-S.
2016-01-01
The classical fast Fourier transform (FFT) allows to compute in quasi-linear time the product of two polynomials, in the {\\em circular convolution ring} R[x]/(x^d−1) --- a task that naively requires quadratic time. Equivalently, it allows to accelerate matrix-vector products when the matrix is *circ
Analyses and Simulation of V-I Characteristics for Solar Cells Based on P-N Junction
Institute of Scientific and Technical Information of China (English)
ZHENG Jian-bang; REN Ju; GUO Wen-ge; HOU Chao-qi
2005-01-01
Through theoretical analyses of the Shockley equation and the difference between a practical P-N junction and its ideal model, the mathematical models of P-N junction and solar cells had been obtained. With Matlab software, the V-I characteristics of diodes and solar cells were simulated, and a computer simulation model of the solar cells based on P-N junction was also established. Based on the simulation model, the influences of solar cell's internal resistances on open-circuit voltage and short-circuit current under certain illumination were numerically analyzed and solved. The simulation results showed that the equivalent series resistance and shunt resistance could strongly affect the V-I characteristics of solar cell, but their influence styles were different.
Energy Technology Data Exchange (ETDEWEB)
Askeland, Thomas Haave; Fjellstad, Bjoern
2007-07-01
Analyses of the income frame regulation model for the network sector in Norway, introduced 1.st of January 2007. The model's treatment of the norm cost is evaluated, especially the effect analyses carried out by a so called Data Envelopment Analysis model. It is argued that there may exist an age lopsidedness in the data set, and that this should and can be corrected in the effect analyses. The adjustment is proposed corrected for by introducing an age parameter in the data set. Analyses of how the calibration effects in the regulation model affect the business' total income frame, as well as each network company's income frame have been made. It is argued that the calibration, the way it is presented, is not working according to its intention, and should be adjusted in order to provide the sector with the rate of reference in return (ml)
Analysing the effect of I1 imidazoline receptor ligands on DSS-induced acute colitis in mice.
Fehér, Ágnes; Tóth, Viktória E; Al-Khrasani, Mahmoud; Balogh, Mihály; Lázár, Bernadette; Helyes, Zsuzsanna; Gyires, Klára; Zádori, Zoltán S
2017-02-01
Imidazoline receptors (IRs) have been recognized as promising targets in the treatment of numerous diseases; and moxonidine and rilmenidine, agonists of I1-IRs, are widely used as antihypertensive agents. Some evidence suggests that IR ligands may induce anti-inflammatory effects acting on I1-IRs or other molecular targets, which could be beneficial in patients with inflammatory bowel disease (IBD). On the other hand, several IR ligands may stimulate also alpha2-adrenoceptors, which were earlier shown to inhibit, but in more recent studies to rather aggravate colitis. Hence, this study aimed to analyse for the first time the effect of various I1-IR ligands on intestinal inflammation. Colitis was induced in C57BL/6 mice by adding dextran sulphate sodium (DSS) to the drinking water for 7 days. Mice were treated daily with different IR ligands: moxonidine and rilmenidine (I1-IR agonists), AGN 192403 (highly selective I1-IR ligand, putative antagonist), efaroxan (I1-IR antagonist), as well as with the endogenous IR agonists agmatine and harmane. It was found that moxonidine and rilmenidine at clinically relevant doses, similarly to the other IR ligands, do not have a significant impact on the macroscopic and histological signs of DSS-evoked inflammation. Likewise, colonic myeloperoxidase and serum interleukin-6 levels remained unchanged in response to these agents. Thus, our study demonstrates that imidazoline ligands do not influence significantly the severity of DSS-colitis in mice and suggest that they probably neither affect the course of IBD in humans. However, the translational value of these findings needs to be verified with other experimental colitis models and human studies.
Generic Quantum Fourier Transforms
Moore, Cristopher; Russell, A; Moore, Cristopher; Rockmore, Daniel; Russell, Alexander
2003-01-01
The quantum Fourier transform (QFT) is the principal algorithmic tool underlying most efficient quantum algorithms. We present a generic framework for the construction of efficient quantum circuits for the QFT by ``quantizing'' the separation of variables technique that has been so successful in the study of classical Fourier transform computations. Specifically, this framework applies the existence of computable Bratteli diagrams, adapted factorizations, and Gel'fand-Tsetlin bases to offer efficient quantum circuits for the QFT over a wide variety a finite Abelian and non-Abelian groups, including all group families for which efficient QFTs are currently known and many new group families. Moreover, the method gives rise to the first subexponential-size quantum circuits for the QFT over the linear groups GL_k(q), SL_k(q), and the finite groups of Lie type, for any fixed prime power q.
Fourier techniques and applications
1985-01-01
The first systematic methods of Fourier analysis date from the early eighteenth century with the work of Joseph Fourier on the problem of the flow of heat. (A brief history is contained in the first paper.) Given the initial tempera ture at all points of a region, the problem was to determine the changes in the temperature distribution over time. Understanding and predicting these changes was important in such areas as the handling of metals and the determination of geological and atmospheric temperatures. Briefly, Fourier noticed that the solution of the heat diffusion problem was simple if the initial temperature dis tribution was sinusoidal. He then asserted that any distri bution can be decomposed into a sum of sinusoids, these being the harmonics of the original function. This meant that the general solution could now be obtained by summing the solu tions of the component sinusoidal problems. This remarkable ability of the series of sinusoids to describe all "reasonable" functions, the sine qua n...
Local properties of Fourier series
Hüseyin Bor
2000-01-01
A theorem on local property of |N¯,pn|k summability of factored Fourier series, which generalizes some known results, and also a general theorem concerning the |N¯,pn|k summability factors of Fourier series have been proved.
Fourier transforms principles and applications
Hansen, Eric W
2014-01-01
Fourier Transforms: Principles and Applications explains transform methods and their applications to electrical systems from circuits, antennas, and signal processors-ably guiding readers from vector space concepts through the Discrete Fourier Transform (DFT), Fourier series, and Fourier transform to other related transform methods. Featuring chapter end summaries of key results, over two hundred examples and four hundred homework problems, and a Solutions Manual this book is perfect for graduate students in signal processing and communications as well as practicing engineers.
Real Clifford Windowed Fourier Transform
Institute of Scientific and Technical Information of China (English)
Mawardi BAHRI; Sriwulan ADJI; Ji Man ZHAO
2011-01-01
We study the windowed Fourier transform in the framework of Clifford analysis, which we call the Clifford windowed Fourier transform (CWFT). Based on the spectral representation of the Clifford Fourier transform (CFT), we derive several important properties such as shift, modulation,reconstruction formula, orthogonality relation, isometry, and reproducing kernel. We also present an example to show the differences between the classical windowed Fourier transform (WFT) and the CWFT. Finally, as an application we establish a Heisenberg type uncertainty principle for the CWFT.
Buhler, J; Owerbach, D; Schäffer, A A; Kimmel, M; Gabbay, K H
1997-01-01
We have developed software and statistical tools for linkage analysis of polygenic diseases. We use type I diabetes mellitus (insulin-dependent diabetes mellitus, IDDM) as our model system. Two susceptibility loci (IDDM1 on 6p21 and IDDM2 on 11p15) are well established, and recent genome searches suggest the existence of other susceptibility loci. We have implemented CASPAR, a software tool that makes it possible to test for linkage quickly and efficiently using multiple polymorphic DNA markers simultaneously in nuclear families consisting of two unaffected parents and a pair of affected siblings (ASP). We use a simulation-based method to determine whether lod scores from a collection of ASP tests are significant. We test our new software and statistical tools to assess linkage of IDDM5 and IDDM7 conditioned on analyses with 1 or 2 other unlinked type I diabetes susceptibility loci. The results from the CASPAR analysis suggest that conditioning of IDDM5 on IDDM1 and IDDM4, and of IDDM7 on IDDM1 and IDDM2 provides significant benefits for the genetic analysis of polygenic loci.
Fourier transforms and convolutions for the experimentalist
Jennison, RC
1961-01-01
Fourier Transforms and Convolutions for the Experimentalist provides the experimentalist with a guide to the principles and practical uses of the Fourier transformation. It aims to bridge the gap between the more abstract account of a purely mathematical approach and the rule of thumb calculation and intuition of the practical worker. The monograph springs from a lecture course which the author has given in recent years and for which he has drawn upon a number of sources, including a set of notes compiled by the late Dr. I. C. Browne from a series of lectures given by Mr. J . A. Ratcliffe of t
Fourier transforms in spectroscopy
Kauppinen, Jyrki
2000-01-01
This modern approach to the subject is clearly and logically structured, and gives readers an understanding of the essence of Fourier transforms and their applications. All important aspects are included with respect to their use with optical spectroscopic data. Based on popular lectures, the authors provide the mathematical fundamentals and numerical applications which are essential in practical use. The main part of the book is dedicated to applications of FT in signal processing and spectroscopy, with IR and NIR, NMR and mass spectrometry dealt with both from a theoretical and practical poi
Feldkhun, Daniel (Inventor); Wagner, Kelvin H. (Inventor)
2013-01-01
Methods and systems are disclosed of sensing an object. A first radiation is spatially modulated to generate a structured second radiation. The object is illuminated with the structured second radiation such that the object produces a third radiation in response. Apart from any spatially dependent delay, a time variation of the third radiation is spatially independent. With a single-element detector, a portion of the third radiation is detected from locations on the object simultaneously. At least one characteristic of a sinusoidal spatial Fourier-transform component of the object is estimated from a time-varying signal from the detected portion of the third radiation.
Directory of Open Access Journals (Sweden)
Elin Bjørge Løken
2009-10-01
Full Text Available SAMMENDRAGEt selvadministrert spørreskjema om utvalgte sider av det vanlige kostholdet er besvart av ca. 60 000 mennog kvinner i de tre første hjerte-karundersøkelsene i Finnmark, Sogn og Fjordane og Oppland (1974-1988.Sammenligning av kostdata hos et utvalg av deltakerne som både besvarte spørreskjemaet og et 24 timerskostintervju, har vist at spørreskjemaet ikke bare ga et brukbart bilde av forbruket av melk, brød,smør/margarin og kaffe, men også for beregnet inntak av energi, protein, fett og kalsium. Skjemaetinneholdt få spørsmål om friske plantematvarer og kan derfor ikke gi data for inntak av antioksidanter.Resultatene viste klare forskjeller i kostholdet mellom menn og kvinner og i forhold til bosted. Videreanalyser har vist statistisk signifikante sammenhenger mellom en eller flere kostkomponenter og risiko forulike typer kreft og lårhalsbrudd. Materialet omfatter en forholdsvis ung kohorte, og kan på sikt væreinteressant for studier av andre sykdommer eller dødsårsaker som antas å ha sammenheng med en ellerflere av de kostkomponentene som spørreskjemaet omfatter. Ved vurdering av resultatene er det viktig å tahensyn til at spørreskjemaet ikke omfattet det totale kostholdet.Løken EB, Solvoll K. Can dietary data from the cardiovascular disease studies in Finnmark,Sogn og Fjordane and Oppland be used to analyse risk for other diseases?Nor J Epidemiol ENGLISH SUMMARYA self-administered questionnaire covering selected aspects of the habitual diet was answered byapproximately 60 000 men and women who participated in the three first screenings of cardiovasculardisease risk factors in the counties of Finnmark, Sogn og Fjordane and Oppland (1974-1988. A subsampleof the subjects was in addition interviewed about their intake of foods and beverages on the day before thequestionnaire was handed out. It appeared that the questionnaire not only provided reasonable data onconsumption of milk, bread, butter/margarine and
Fast Fourier transform telescope
Tegmark, Max; Zaldarriaga, Matias
2009-04-01
We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore’s law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog2N rather than N2) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.
Hackel, L.A.; Hermann, M.R.; Dane, C.B.; Tiszauer, D.H.
1995-12-12
A solid state laser is frequency tripled to 0.3 {micro}m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only about 1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power. 1 fig.
Hackel, Lloyd A.; Hermann, Mark R.; Dane, C. Brent; Tiszauer, Detlev H.
1995-01-01
A solid state laser is frequency tripled to 0.3 .mu.m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only .about.1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power.
Cafri, Guy; Kromrey, Jeffrey D.; Brannick, Michael T.
2010-01-01
This article uses meta-analyses published in "Psychological Bulletin" from 1995 to 2005 to describe meta-analyses in psychology, including examination of statistical power, Type I errors resulting from multiple comparisons, and model choice. Retrospective power estimates indicated that univariate categorical and continuous moderators, individual…
Fourier Transform Spectrometer System
Campbell, Joel F. (Inventor)
2014-01-01
A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.
Alexandrov, Mikhail D.; Cairns, Brian; Mishchenko, Michael I.
2012-01-01
We present a novel technique for remote sensing of cloud droplet size distributions. Polarized reflectances in the scattering angle range between 135deg and 165deg exhibit a sharply defined rainbow structure, the shape of which is determined mostly by single scattering properties of cloud particles, and therefore, can be modeled using the Mie theory. Fitting the observed rainbow with such a model (computed for a parameterized family of particle size distributions) has been used for cloud droplet size retrievals. We discovered that the relationship between the rainbow structures and the corresponding particle size distributions is deeper than it had been commonly understood. In fact, the Mie theory-derived polarized reflectance as a function of reduced scattering angle (in the rainbow angular range) and the (monodisperse) particle radius appears to be a proxy to a kernel of an integral transform (similar to the sine Fourier transform on the positive semi-axis). This approach, called the rainbow Fourier transform (RFT), allows us to accurately retrieve the shape of the droplet size distribution by the application of the corresponding inverse transform to the observed polarized rainbow. While the basis functions of the proxy-transform are not exactly orthogonal in the finite angular range, this procedure needs to be complemented by a simple regression technique, which removes the retrieval artifacts. This non-parametric approach does not require any a priori knowledge of the droplet size distribution functional shape and is computationally fast (no look-up tables, no fitting, computations are the same as for the forward modeling).
Scarfone, A. M.
2017-08-01
We present a new formulation of Fourier transform in the picture of the κ-algebra derived in the framework of the κ-generalized statistical mechanics. The κ-Fourier transform is obtained from a κ-Fourier series recently introduced by Scarfone (2013). The kernel of this transform, that reduces to the usual exponential phase in the κ → 0 limit, is composed by a κ-deformed phase and a damping factor that gives a wavelet-like behaviour. We show that the κ-Fourier transform is isomorph to the standard Fourier transform through a changing of time and frequency variables. Nevertheless, the new formalism is useful to study, according to Fourier analysis, those functions defined in the realm of the κ-algebra. As a relevant application, we discuss the central limit theorem for the κ-sum of n-iterate statistically independent random variables.
Quadrature formulas for Fourier coefficients
Bojanov, Borislav
2009-09-01
We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.
Wavelet Analyses and Applications
Bordeianu, Cristian C.; Landau, Rubin H.; Paez, Manuel J.
2009-01-01
It is shown how a modern extension of Fourier analysis known as wavelet analysis is applied to signals containing multiscale information. First, a continuous wavelet transform is used to analyse the spectrum of a nonstationary signal (one whose form changes in time). The spectral analysis of such a signal gives the strength of the signal in each…
Directory of Open Access Journals (Sweden)
Vera E Heininga
Full Text Available In psychiatric genetics research, the volume of ambivalent findings on gene-environment interactions (G x E is growing at an accelerating pace. In response to the surging suspicions of systematic distortion, we challenge the notion of chance capitalization as a possible contributor. Beyond qualifying multiple testing as a mere methodological issue that, if uncorrected, leads to chance capitalization, we advance towards illustrating the potential benefits of multiple tests in understanding equivocal evidence in genetics literature.We focused on the interaction between the serotonin-transporter-linked promotor region (5-HTTLPR and childhood adversities with regard to depression. After testing 2160 interactions with all relevant measures available within the Dutch population study of adolescents TRAILS, we calculated percentages of significant (p < .05 effects for several subsets of regressions. Using chance capitalization (i.e. overall significance rate of 5% alpha and randomly distributed findings as a competing hypothesis, we expected more significant effects in the subsets of regressions involving: 1 interview-based instead of questionnaire-based measures; 2 abuse instead of milder childhood adversities; and 3 early instead of later adversities. Furthermore, we expected equal significance percentages across 4 male and female subsamples, and 5 various genotypic models of 5-HTTLPR.We found differences in the percentages of significant interactions among the subsets of analyses, including those regarding sex-specific subsamples and genetic modeling, but often in unexpected directions. Overall, the percentage of significant interactions was 7.9% which is only slightly above the 5% that might be expected based on chance.Taken together, multiple testing provides a novel approach to better understand equivocal evidence on G x E, showing that methodological differences across studies are a likely reason for heterogeneity in findings - but chance
Reflective Fourier ptychography.
Pacheco, Shaun; Zheng, Guoan; Liang, Rongguang
2016-02-01
The Fourier ptychography technique in reflection mode has great potential applications in tissue imaging and optical inspection, but the current configuration either has a limitation on cut-off frequency or is not practical. By placing the imaging aperture stop outside the illumination path, the illumination numerical aperture (NA) can be greater than the imaging NA of the objective lens. Thus, the cut-off frequency achieved in the proposed optical system is greater than twice the objective's NA divided by the wavelength (2NAobj/λ ), which is the diffraction limit for the cut-off frequency in an incoherent epi-illumination configuration. We experimentally demonstrated that the synthesized NA is increased by a factor of 4.5 using the proposed optical concept. The key advantage of the proposed system is that it can achieve high-resolution imaging over a large field of view with a simple objective. It will have a great potential for applications in endoscopy, biomedical imaging, surface metrology, and industrial inspection.
Reconstruction in Fourier space
Burden, A.; Percival, W. J.; Howlett, C.
2015-10-01
We present a fast iterative fast Fourier transform (FFT) based reconstruction algorithm that allows for non-parallel redshift-space distortions (RSDs). We test our algorithm on both N-body dark matter simulations and mock distributions of galaxies designed to replicate galaxy survey conditions. We compare solenoidal and irrotational components of the redshift distortion and show that an approximation of this distortion leads to a better estimate of the real-space potential (and therefore faster convergence) than ignoring the RSD when estimating the displacement field. Our iterative reconstruction scheme converges in two iterations for the mock samples corresponding to Baryon Oscillation Spectroscopic Survey CMASS Data Release 11 when we start with an approximation of the RSD. The scheme takes six iterations when the initial estimate, measured from the redshift-space overdensity, has no RSD correction. Slower convergence would be expected for surveys covering a larger angle on the sky. We show that this FFT based method provides a better estimate of the real-space displacement field than a configuration space method that uses finite difference routines to compute the potential for the same grid resolution. Finally, we show that a lognormal transform of the overdensity, used as a proxy for the linear overdensity, is beneficial in estimating the full displacement field from a dense sample of tracers. However, the lognormal transform of the overdensity does not perform well when estimating the displacements from sparser simulations with a more realistic galaxy density.
Grafakos, Loukas
2014-01-01
This text is addressed to graduate students in mathematics and to interested researchers who wish to acquire an in depth understanding of Euclidean Harmonic analysis. The text covers modern topics and techniques in function spaces, atomic decompositions, singular integrals of nonconvolution type, and the boundedness and convergence of Fourier series and integrals. The exposition and style are designed to stimulate further study and promote research. Historical information and references are included at the end of each chapter. This third edition includes a new chapter entitled "Multilinear Harmonic Analysis" which focuses on topics related to multilinear operators and their applications. Sections 1.1 and 1.2 are also new in this edition. Numerous corrections have been made to the text from the previous editions and several improvements have been incorporated, such as the adoption of clear and elegant statements. A few more exercises have been added with relevant hints when necessary. Reviews fr...
POINTWISE FOURIER INVERSION OF DISTRIBUTIONS
Institute of Scientific and Technical Information of China (English)
F.J.González Vieli
2008-01-01
We show that,given a tempered distribution T whose Fourier transform is a function of polynomial growth and a point x in Rn at which T has the value τ(in the sense of Lojasiewicz),the Fourier integral of T at x is summable in Bochner-Riesz means to τ.
Wavelet-fractional Fourier transforms
Institute of Scientific and Technical Information of China (English)
Yuan Lin
2008-01-01
This paper extends the definition of fractional Fourier transform (FRFT) proposed by Namias V by using other orthonormal bases for L2 (R) instead of Hermite-Ganssian functions.The new orthonormal basis is gained indirectly from multiresolution analysis and orthonormal wavelets. The so defined FRFT is called wavelets-fractional Fourier transform.
Digital Fourier analysis advanced techniques
Kido, Ken'iti
2015-01-01
This textbook is a thorough, accessible introduction to advanced digital Fourier analysis for advanced undergraduate and graduate students. Assuming knowledge of the Fast Fourier Transform, this book covers advanced topics including the Hilbert transform, cepstrum analysis, and the two-dimensional Fourier transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Advanced Techniques" includes practice problems and thorough Appendices. As a central feature, the book includes interactive applets (available online) that mirror the illustrations. These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. The applet source code in Visual Basic is provided online, enabling advanced students to tweak and change the programs for more sophisticated results. A complete, intuitive guide, "Digital Fourier Analysis - Advanced Techniques" is an essential reference for students in science and engineering.
2009-01-01
Phase interactions among signals of physical and physiological systems can provide useful information about the underlying control mechanisms of the systems. Physical and biological recordings are often noisy and exhibit nonstationarities that can affect the estimation of phase interactions. We systematically studied effects of nonstationarities on two phase analyses including (i) the widely used transfer function analysis (TFA) that is based on Fourier decomposition and (ii) the recently pro...
Hansen, Kari Edvardsdal
2003-01-01
Sammendrag: Oppgaven er en teoretisk analyse av ’totalitarisme’ som politisk konsept. Utgangspunktet er Hannah Arendts teori om totalitære samfunn slik hun gjør rede for i Origins of Totalitarianism (1951). Hun tar utgangspunkt i Hitlers Tyskland og Sovjetunionen under Stalin, og ved å trekke paralleller mellom disse regimene identifiserer hun kjennetegn som hun mener samlet utgjør fenomenet ’totalitarisme’/ ’totalitær stat’. De kjennetegnene Arendt identifiserer som definitoriske kjennet...
Fourier phase in Fourier-domain optical coherence tomography.
Uttam, Shikhar; Liu, Yang
2015-12-01
Phase of an electromagnetic wave propagating through a sample-of-interest is well understood in the context of quantitative phase imaging in transmission-mode microscopy. In the past decade, Fourier-domain optical coherence tomography has been used to extend quantitative phase imaging to the reflection-mode. Unlike transmission-mode electromagnetic phase, however, the origin and characteristics of reflection-mode Fourier phase are poorly understood, especially in samples with a slowly varying refractive index. In this paper, the general theory of Fourier phase from first principles is presented, and it is shown that Fourier phase is a joint estimate of subresolution offset and mean spatial frequency of the coherence-gated sample refractive index. It is also shown that both spectral-domain phase microscopy and depth-resolved spatial-domain low-coherence quantitative phase microscopy are special cases of this general theory. Analytical expressions are provided for both, and simulations are presented to explain and support the theoretical results. These results are further used to show how Fourier phase allows the estimation of an axial mean spatial frequency profile of the sample, along with depth-resolved characterization of localized optical density change and sample heterogeneity. Finally, a Fourier phase-based explanation of Doppler optical coherence tomography is also provided.
Montgomery, Hugh L
2015-01-01
Hugh Montgomery has written a book which both students and faculty should appreciate. I wish it had been written 15 years ago so I could have shared it with students. It is a gem. -Richard Askey, University of Wisconsin-Madison Montgomery has written an exquisite text combining basic material, exciting examples, advanced topics, wonderful historical notes, and excellent exercises. It is absolutely compelling and masterful! -John Benedetto, University of Maryland This nice book is likely to be especially successful. l feel that the author has managed admirably to bring to light both the beauty
Fourier analysis and stochastic processes
Brémaud, Pierre
2014-01-01
This work is unique as it provides a uniform treatment of the Fourier theories of functions (Fourier transforms and series, z-transforms), finite measures (characteristic functions, convergence in distribution), and stochastic processes (including arma series and point processes). It emphasises the links between these three themes. The chapter on the Fourier theory of point processes and signals structured by point processes is a novel addition to the literature on Fourier analysis of stochastic processes. It also connects the theory with recent lines of research such as biological spike signals and ultrawide-band communications. Although the treatment is mathematically rigorous, the convivial style makes the book accessible to a large audience. In particular, it will be interesting to anyone working in electrical engineering and communications, biology (point process signals) and econometrics (arma models). A careful review of the prerequisites (integration and probability theory in the appendix, Hilbert spa...
DEFF Research Database (Denmark)
Steensen, Jette Johanne
Afhandlingen bidrager til at undersøge, hvordan såvel Bourdieus begreb om habitus som Archers begreb "den interne konversation" kan anvendes til at belyse lærerstuderendes karriereorientering og fremtidsperspektiver i to lande. Med afsæt i kritisk realisme som videnskabsteoretisk grundlag muliggø...
DEFF Research Database (Denmark)
Steensen, Jette Johanne
Afhandlingen bidrager til at undersøge, hvordan såvel Bourdieus begreb om habitus som Archers begreb "den interne konversation" kan anvendes til at belyse lærerstuderendes karriereorientering og fremtidsperspektiver i to lande. Med afsæt i kritisk realisme som videnskabsteoretisk grundlag muliggør...
Fourier series and orthogonal functions
Davis, Harry F
1963-01-01
This incisive text deftly combines both theory and practical example to introduce and explore Fourier series and orthogonal functions and applications of the Fourier method to the solution of boundary-value problems. Directed to advanced undergraduate and graduate students in mathematics as well as in physics and engineering, the book requires no prior knowledge of partial differential equations or advanced vector analysis. Students familiar with partial derivatives, multiple integrals, vectors, and elementary differential equations will find the text both accessible and challenging.
National Research Council Canada - National Science Library
Austin, Peter C
2009-01-01
... the statistical significance of the treatment effect. We conducted a series of Monte Carlo simulations to examine the impact of ignoring the matched nature of the propensity-score matched sample on Type I error rates, coverage of confidence...
En analyse af potentialet for salg af fødevarer gennem Internettet i Danmark og England
DEFF Research Database (Denmark)
Ramus, Kim Bjarne
2001-01-01
I Kim Ramus ph.d.-projekt gennemføres en undersøgelse af danske og britiske forbrugeres holdninger og præferencer til handel med fødevarer på Internettet, hvor formålet er at finde potentialet for salg af fødevarer online. Internettet er ganske udbredt i begge lande, men England er dog et godt st...
Energy Technology Data Exchange (ETDEWEB)
Dubgaard, A.; Moeller Laugesen, F.; Staehl, E.E.; Bang, J.R.; Schou, E.; Jacobsen, Brian H.; Oerum, J.E.; Dejgaerd Jensen, J.
2013-08-15
The report contains the contributions by the Institute of Food and Resource Economics (IFRO) to a Danish Government appraisal of greenhouse gas (GHG) reduction measures. The policy goal is a 40 per cent reduction in total Danish GHG emissions by 2020 compared to 1990. The GHGs analysed in the present study include emissions of CO{sub 2}, nitrous oxide and methane plus soil carbon sequestration. The purpose of the study is to identify GHG mitigation measures related to agriculture which can deliver cost-effective contributions to the targeted reduction in GHG emissions in Denmark. A total of 21 GHG mitigation measures are included in the assessment. The stipulated implementation period is 2013 to 2020. The cost calculations have a time horizon equal to 30 years, i.e. from 2013 to 2042. The GHG reduction potential, expressed in CO{sub 2} equivalents (CO{sub 2}-eq), is calculated as the sum of the effect on the emission of CO{sub 2} (with and without changes in soil carbon), methane and nitrous oxide. The 21 mitigation measures are listed below (figures in brackets show the assumed implementation potential): 1. Biogas from livestock manure/slurry (10 % of total slurry production) 2. Biogas from slurry and maize (10 % of total slurry production) 3. Biogas from organic clover 4. Additional fat in diet for dairy cows (80% of conventional dairy cow stock and 20 % of organic dairy cow stock) 5. Additional concentrated feed in diet for other cattle (25 % of cattle stock under 2 years of age) 6. Prolonged lactation period for dairy cows (10 % of dairy cow stock) 7. Acidification of slurry (10 % of total slurry production) 8. Covers on slurry containers (40 % of total slurry production) 9. Cooling of pig slurry (10 % of pig slurry) 10. Nitrification inhibitors in nitrate fertilisers (100 % of chemical fertilisers with nitrogen) 11. Increased nitrogen utilization requirement for degassed slurry in nitrogen quota system (50 % of total slurry production) 12. Increased nitrogen
Flem, Kato Nogva
2014-01-01
Ei samanlikning og analyse av Busoni sin transkripsjon av Bach sin Chaconne frå partita nr. 2 for solofiolin. Partita for Violin No. 2 was written by Johann Sebastian Bach during 1717-1723 and consists of five movements; Allemande, Courante, Sarabande, Gigue and Chaconne. The chaconne is longer than the rest of the piece combined, and is frequently played separately. Yehudi Menuhin calls the Chaconne "the greatest structure for solo violin that exists." (Menuhin, 1997, p. 236) Violinist...
Gjenåpningen av Veumbekken fra kulvert til åpen kanal : hydraulisk analyse og modellering i SWMM
2016-01-01
Klimaendringene medfører at vi får et stadig varmere og mer ekstremt klima. De siste årene har det vært en økning i både temperatur, nedbørsmengder og nedbørintensitet i Norge, og denne trenden vil fortsette dersom man ikke klarer å redusere utslipp av klimagasser. For håndtering av overvann byr dette på store problemer da overvannsystemene ikke er dimensjonert for å takle den økende avrenningen forårsaket av kraftigere regnbyger, urbanisering og fortetting. Veumbekken renner igjennom Veum...
Huang, Yu-Hsuan; Lee, Yuan-Pern
2014-06-01
The Criegee intermediates are carbonyl oxides that play key roles in ozonolysis of unsaturated organic compounds. This mechanism was first proposed by Criegee in 1949, but the first direct observation of the simplest Criegee intermediate CH2OO in the gaseous phase has been reported only recently using photoionization mass spectrometry. Our group has reported the low-resolution IR spectra of CH2OO, produced from the reaction of CH2I + O2, with a second-generation step-scan Fourier-transfom IR absorption spectrometer. The spectral assignments were based on comparison of observed vibrational wavenumbers and rotational contours with theoretical predictions. Here, we report the IR absorption spectra of CH2OO at a resolution of 0.32 wn, showing partially rotationally-resolved structures. The origins of the νb{3}, νb{4}, νb{6}, and νb{8} vibrational modes of CH2OO are determined to be 1434.1, 1285.7, 909.2, and 847.3 wn, respectively. With the analysis of the vibration-rotational spectra, we provide a definitive assignment of these bands to CH2OO. The observed vibrational wavenumbers indicate a zwitterionic contribution to this singlet biradical showing a strengthened C-O bond and a weakened O-O bond. This zwitterionic character results to an extremely rapid self reaction via a cyclic dimer to form 2H2CO + O2 (1Δg). Another group of weak transient IR bands centered at 1231.5, 1213.3, and 899.8 wn are also observed. These bands might be contributed from dioxirane, which was postulated to be another important intermediate that might be isomerized from the Criegee intermediate in the reaction of O3 with 1-alkenes. O. Welz, J. D. Savee, D. L. Osborn, S. S.Vasu, C. J. Percival, D. E. Shallcross, and C. A. Taatjes, Science 335, 204 (2012). Y.-T. Su, Y.-H. Huang, H. A.Witek, and Y.-P. Lee, Science 340, 174 (2013).
Pragmatic Analyses of Martin Luther King (Jr)'s Speech: "I Have a Dream"--An Introspective Prognosis
Josiah, Ubong E.; Oghenerho, Gift
2015-01-01
This paper investigates the speech of Martin Luther King (Jr.) titled: "I Have a Dream", presented in 1963 at the Lincoln Memorial. This speech is selected for use because it involves a speaker and an audience who belong to a particular speech community. The speech is about the failed promises by the Americans whose dream advocate…
Global Sensitivity and Data-Worth Analyses in iTOUGH2: User's Guide
Energy Technology Data Exchange (ETDEWEB)
Wainwright, Haruko Murakami [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Univ. of California, Berkeley, CA (United States); Finsterle, Stefan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Univ. of California, Berkeley, CA (United States)
2016-07-15
This manual explains the use of local sensitivity analysis, the global Morris OAT and Sobol’ methods, and a related data-worth analysis as implemented in iTOUGH2. In addition to input specification and output formats, it includes some examples to show how to interpret results.
Corrected Fourier series and its application to function approximation
Directory of Open Access Journals (Sweden)
Qing-Hua Zhang
2005-01-01
Full Text Available Any quasismooth function f(x in a finite interval [0,x0], which has only a finite number of finite discontinuities and has only a finite number of extremes, can be approximated by a uniformly convergent Fourier series and a correction function. The correction function consists of algebraic polynomials and Heaviside step functions and is required by the aperiodicity at the endpoints (i.e., f(0≠f(x0 and the finite discontinuities in between. The uniformly convergent Fourier series and the correction function are collectively referred to as the corrected Fourier series. We prove that in order for the mth derivative of the Fourier series to be uniformly convergent, the order of the polynomial need not exceed (m+1. In other words, including the no-more-than-(m+1 polynomial has eliminated the Gibbs phenomenon of the Fourier series until its mth derivative. The corrected Fourier series is then applied to function approximation; the procedures to determine the coefficients of the corrected Fourier series are illustrated in detail using examples.
Thermo-mechanical and damage analyses of EAST carbon divertor under type-I ELMy H-mode operation
Energy Technology Data Exchange (ETDEWEB)
Li, W.X. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Song, Y.T. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China); Ye, M.Y. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Peng, X.B., E-mail: pengxb@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu, S.T. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Qian, X.Y.; Zhu, C.C. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China)
2016-04-15
Highlights: • Type-I ELMy H-mode is one of the most severe operating environment in tokamak. • An actual time-history heat load has been used in thermo-mechanical analysis. • The analysis results are time-dependent during the whole discharge process. • The analysis could be very useful in evaluating the operational capability of the divertor. - Abstract: The lower carbon divertor has been used since 2008 in EAST, and many significant physical results, like the 410 s long pulse discharge and the 32 s H-mode operation, have been achieved. As the carbon divertor will still be used in the next few years while the injected auxiliary heating power would be increased gradually, it’s necessary to evaluate the operational capability of the carbon divertor under the heat loads during future operation. In this paper, an actual time-history heat load during type-I ELMy H-mode from EAST experiment, as one of the most severe operating environment in tokamak, has been used in the calculation and analysis. The finite element (FE) thermal and mechanical calculations have been carried out to analysis the stress and deformation of the carbon divertor during the heat loads. According to the results, the main impact on the overall temperature comes from the relative stable phase before and after the type-I ELMs and local peak load, and the transient thermal load such as type-I ELMy only has a significant effect on the surface temperature of the graphite tiles. The carbon divertor would work with high stress near the screw bolts in the current operational conditions, because of high preload and conservative frictional coefficient between the bolts and heatsink. For the future operation, new plasma facing materials (PFM) and divertor technology should be developed.
2012-09-01
8217 El=-2.5’ Sheet pile tip ERDC/ITL TR-12-4 10 (CWALSHT) ( Dawkins 1991) and procedures outlined in HQUSACE (1994). The initial design depth of...mechanics. 6th ed. New York: Chapman and Hall. Dawkins , W. P. 1991. User’s guide: Computer program for design and analysis of sheet- pile walls by... Dawkins , R. Mosher, and I. Hallal. 1997. Soil-structure interaction effects in floodwalls. Electronic Journal of Geotechnical Engineering. http
McKee, Edwin D.; Crosby, Eleanor J.; Bachman, George O.; Bell, Kenneth G.; Dixon, George H.; Frezon, Sherwood E.; Glick, Ernest E.; Irwin, William P.; Mallory, William W.; Mapel, William J.; Maughan, Edwin K.; Prichard, George E.; Shideler, Gerald L.; Stewart, Gary F.; Wanless, Harold R.; Wilson, Richard F.
1975-01-01
The Pennsylvanian is the fourth geologic system to be analyzed and synthesized by geologists of the U.S. Geological Survey in the form of a paleotectonic study covering the conterminous United States. Earlier investigations were of the Jurassic, Triassic, and Permian Systems. Results were published as Miscellaneous Geologic Investigation Maps I-175, I-300, and I-450 and in Professional Paper 515. The objective of these investigations is to provide in graphic form the factual basis for recognition of tectonic events of each system on a countrywide scale. The maps in this publication depict rock thickness, generalized lithology, ancient geography, and other regional relations of the Pennsylvanian System. Method of preparation of the maps, the stratigraphic limits of the map units, and various stratigraphic and structural features and their probable tectonic significance are discussed. Pennsylvanian data were largely compiled between 1961 and 196 by 16 geologists, including the late Harold R. Wanless, who covered the five eastern regions and contributed to several of the special studies. The areas of responsibility of the cooperating geologists are indicated in figure 1. Work in Kansas was done by Gary F. Stewart, of the Kansas Geological Survey. Results of this investigation are presented in three units. Part I comprises an introduction and 17 chapters, each describing and discussing one of the regions in which the conterminous United States was divided for purposes of study and mapping. Part II is a synthesis of Pennsylvanian history to accompany interpretive maps of the five divisions of the Pennsylvanian System treated in this publication; it also includes a series of chapters on depositional environments, climatic conditions, and economic products of the system. The final section of part II is devoted to an index of localities and sources used in construction of the principal maps of this publication. Part III consists of the plates on which are presented the
DEFF Research Database (Denmark)
Nielsen, Stine Frydendal; Thing, Lone Friis
-projektet på Rysensteen som gymnasieintervention retter sig ikke udelukkende mod idrætstimerne, men har fokus på skolens miljø som helhed – dvs. skolens organisering, lokalernes beskaffenhed; frikvarter og friidræt og skolekulturen – inspireret af Pate et al (2005). Den idrætsfaglige klasse i...
Guynn, E. G.; Ochoa, Ozden O.; Bradley, Walter L.
1992-01-01
The effects of the stacking sequence (orientation of plies adjacent to the 0-deg plies), free surfaces, fiber/matrix interfacial bond strength, initial fiber waviness, resin-rich regions, and nonlinear shear constitutive behavior of the resin on the initiation of fiber microbuckling in thermoplastic composites were investigated using nonlinear geometric and nonlinear 2D finite-element analyses. Results show that reductions in the resin shear tangent modulus, large amplitudes of the initial fiber waviness, and debonds each cause increases in the localized matrix shear strains; these increases lead in turn to premature initiation of fiber microbuckling. The numerical results are compared to experimental data obtained using three thermoplastic composite material systems: (1) commercial APC-2, (2) QUADRAX Unidirectional Interlaced Tape, and AU4U/PEEK.
Fourier Series, the DFT and Shape Modelling
DEFF Research Database (Denmark)
Skoglund, Karl
2004-01-01
This report provides an introduction to Fourier series, the discrete Fourier transform, complex geometry and Fourier descriptors for shape analysis. The content is aimed at undergraduate and graduate students who wish to learn about Fourier analysis in general, as well as its application to shape...
Fourier processing of quantum light
Poem, Eilon; Lahini, Yoav; Silberberg, Yaron
2012-01-01
It is shown that a classical optical Fourier processor can be used for the shaping of quantum correlations between two or more photons, and the class of Fourier masks applicable in the multiphoton Fourier space is identified. This concept is experimentally demonstrated using two types of periodic phase masks illuminated with path-entangled photon pairs, a highly non-classical state of light. Applied first were sinusoidal phase masks, emulating two-particle quantum walk on a periodic lattice, yielding intricate correlation patterns with various spatial bunching and anti-bunching effects depending on the initial state. Then, a periodic Zernike-like filter was applied on top of the sinusoidal phase masks. Using this filter, phase information lost in the original correlation measurements was retrieved.
Fast Numerical Nonlinear Fourier Transforms
Wahls, Sander
2014-01-01
The nonlinear Fourier transform, which is also known as the forward scattering transform, decomposes a periodic signal into nonlinearly interacting waves. In contrast to the common Fourier transform, these waves no longer have to be sinusoidal. Physically relevant waveforms are often available for the analysis instead. The details of the transform depend on the waveforms underlying the analysis, which in turn are specified through the implicit assumption that the signal is governed by a certain evolution equation. For example, water waves generated by the Korteweg-de Vries equation can be expressed in terms of cnoidal waves. Light waves in optical fiber governed by the nonlinear Schr\\"dinger equation (NSE) are another example. Nonlinear analogs of classic problems such as spectral analysis and filtering arise in many applications, with information transmission in optical fiber, as proposed by Yousefi and Kschischang, being a very recent one. The nonlinear Fourier transform is eminently suited to address them ...
Directory of Open Access Journals (Sweden)
Maja Miličević
2016-09-01
Full Text Available In this paper we discuss the parallel manual normalisation of samples extracted from Croatian and Serbian Twitter corpora. We describe the datasets, outline the unified guidelines provided to annotators, and present a series of analyses of standard-to-non-standard transformations found in the Twitter data. The results show that closed part-of-speech classes are transformed more frequently than the open classes, that the most frequently transformed lemmas are auxiliary and modal verbs, interjections, particles and pronouns, that character deletions are more frequent than insertions and replacements, and that more transformations occur at the word end than in other positions. Croatian and Serbian are found to share many, but not all transformation patterns; while some of the discrepancies can be ascribed to the structural differences between the two languages, others appear to be better explained by looking at extralinguistic factors. The produced datasets and their initial analyses can be used for studying the properties of non-standard language, as well as for developing language technologies for non-standard data.
Sastry, V. S. S.; Polimeno, Antonino; Crepeau, Richard H.; Freed, Jack H.
1996-10-01
Two-dimensional Fourier transform (2D-FT) electron spin resonance (ESR) studies on the rigid rodlike cholestane (CSL) spin-label in the liquid crystal solvent 4O,8 (butoxy benzylidene octylaniline) are reported. These experiments were performed over a wide temperature range: 96 °C to 25 °C covering the isotropic (I), nematic (N), smectic A (SA), smectic B (SB), and crystal (C) phases. It is shown that 2D-FT-ESR, especially in the form of 2D-ELDOR (two-dimensional electron-electron double resonance) provides greatly enhanced sensitivity to rotational dynamics than previous cw-ESR studies on this and related systems. This sensitivity is enhanced by obtaining a series of 2D-ELDOR spectra as a function of mixing time, Tm, yielding essentially a three-dimensional experiment. Advantage is taken of this sensitivity to study the applicability of the model of a slowly relaxing local structure (SRLS). In this model, a dynamic cage of solvent molecules, which relaxes on a slower time scale than the CSL solute, provides a local orienting potential in addition to that of the macroscopic aligning potential in the liquid crystalline phase. The theory of Polimeno and Freed for SRLS in the ESR slow motional regime is extended by utilizing the theory of Lee et al. to include 2D-FT-ESR experiments, and it serves as the basis for the analysis of the 2D-ELDOR experiments. It is shown that the SRLS model leads to significantly improved non-linear least squares fits to experiment over those obtained with the standard model of Brownian reorientation in a macroscopic aligning potential. This is most evident for the SA phase, and the use of the SRLS model also removes the necessity of fitting with the unreasonably large CSL rotational asymmetries in the smectic phases that are required in both the cw-ESR and 2D-ELDOR fits with the standard model. The cage potential is found to vary from about kBT in the isotropic phase to greater than 2kBT in the N and SA phases, with an abrupt drop to
Ruud, Jørgen
2005-01-01
Temaet for denne hovedoppgaven er todelt. Jeg ønsker å sette søkelyset på hva finansiell stabilitet er, og på hvilke indikatorer som kan brukes til å måle finansiell stabilitet. Det siste punktet trenger en nærmere forklaring. Myndighetene kan forebygge finansiell ustabilitet gjennom blant annet et velutviklet tilsyns- og reguleringssystem . Forebyggende tiltak er kun forbyggende og forhindrer ikke at finanskriser fra tid til annen inntreffer i økonomien. Dette har ført til økt interesse for ...
Fourier transforms in the complex domain
Wiener, N
1934-01-01
With the aid of Fourier-Mellin transforms as a tool in analysis, the authors were able to attack such diverse analytic questions as those of quasi-analytic functions, Mercer's theorem on summability, Milne's integral equation of radiative equilibrium, the theorems of MÃ¼nz and SzÃ¡sz concerning the closure of sets of powers of an argument, Titchmarsh's theory of entire functions of semi-exponential type with real negative zeros, trigonometric interpolation and developments in polynomials of the form \\sum^N_1A_ne^{i\\lambda_nx}, lacunary series, generalized harmonic analysis in the complex domain,
Static Fourier transform infrared spectrometer.
Schardt, Michael; Murr, Patrik J; Rauscher, Markus S; Tremmel, Anton J; Wiesent, Benjamin R; Koch, Alexander W
2016-04-01
Fourier transform spectroscopy has established itself as the standard method for spectral analysis of infrared light. Here we present a robust and compact novel static Fourier transform spectrometer design without any moving parts. The design is well suited for measurements in the infrared as it works with extended light sources independent of their size. The design is experimentally evaluated in the mid-infrared wavelength region between 7.2 μm and 16 μm. Due to its large etendue, its low internal light loss, and its static design it enables high speed spectral analysis in the mid-infrared.
PHASE ANALYSES OF URANIUM-BEARING MINERALS FROM THE HIGH GRADE ORE, NOPAL I, PENA BLANCA, MEXICO
Energy Technology Data Exchange (ETDEWEB)
M. Ren; P. Goodell; A. Kelts; E.Y. Anthony; M. Fayek; C. Fan; C. Beshears
2005-07-11
The Nopal I uranium deposit is located in the Pena Blanca district, approximately 40 miles north of Chihuahua City, Mexico. The deposit was formed by hydrothermal processes within the fracture zone of welded silicic volcanic tuff. The ages of volcanic formations are between 35 to 44 m.y. and there was secondary silicification of most of the formations. After the formation of at least part of the uranium deposit, the ore body was uplifted above the water table and is presently exposed at the surface. Detailed petrographic characterization, electron microprobe backscatter electron (BSE) imagery, and selected x-ray maps for the samples from Nopal I high-grade ore document different uranium phases in the ore. There are at least two stages of uranium precipitation. A small amount of uraninite is encapsulated in silica. Hexavalent uranium may also have been a primary precipitant. The uranium phases were precipitated along cleavages of feldspars, and along fractures in the tuff. Energy dispersive spectrometer data and x-ray maps suggest that the major uranium phases are uranophane and weeksite. Substitutions of Ca and K occur in both phases, implying that conditions were variable during the mineralization/alteration process, and that compositions of the original minerals have a major influence on later stage alteration. Continued study is needed to fully characterize uranium behavior in these semi-arid to arid conditions.
Myers, A D; Nichol, R C; Richards, G T; Schneider, D P; Bahcall, N A; Myers, Adam D.; Brunner, Robert J.; Nichol, Robert C.; Richards, Gordon T.; Schneider, Donald P.; Bahcall, Neta A.
2006-01-01
Using ~300,000 photometrically classified quasars, by far the largest quasar sample ever used for such analyses, we study the redshift and luminosity evolution of quasar clustering on scales of ~50 kpc/h to ~20 Mpc/h from redshifts of z~0.75 to z~2.28. We parameterize our clustering amplitudes using realistic dark matter models, and find that a LCDM power spectrum provides a superb fit to our data with a redshift-averaged quasar bias of b_Q = 2.41+/-0.08 ($P_{99.6% using our data set alone, increasing to >99.9999% if stellar contamination is not explicitly parameterized. We measure the quasar classification efficiency across our full sample as a = 95.6 +/- ^{4.4}_{1.9}%, a star-quasar separation comparable with the star-galaxy separation in many photometric studies of galaxy clustering. We derive the mean mass of the dark matter halos hosting quasars as MDMH=(5.2+/-0.6)x10^{12} M_solar/h. At z~1.9 we find a $1.5\\sigma$ deviation from luminosity-independent quasar clustering; this suggests that increasing our ...
Energy Technology Data Exchange (ETDEWEB)
Phelippeau,A.; Pommier, S.; Tsakalakos, T.; Clavel, M.; Prioul, C.
2006-01-01
Cold drawing steel wires lead to an increase of their mechanical strength and to a drop of their ductility. The increase of their mechanical strength has long been related to the reduction of the various material scales by plastic deformation, but the mechanisms controlling their elongation to failure have received relatively little attention. It is usually found that heavily deformed materials show a tendency to plastic strain localization and necking. However, in this paper it is shown that, though the steel wires are plastically deformed up to strain levels as high as 3.5, a significant capability of plastic deformation is preserved in as-drawn wires. This apparent contradiction is resolved by the existence of residual stresses inside the wire. Finite element analyses have been conducted in order to show that residual stresses, inherited from the drawing process, are sufficient to produce a significant hardening effect during a post-drawing tensile test, without introducing any hardening in the local material behavior. The main conclusion of this paper is that once the material has lost its hardening capabilities, residual stresses, inherited from the process, control the elongation of cold drawn wires. The finite element method allowed also the determination of the residual stress field that would lead to the best agreement between the simulated and the experimental stress strain curve of as-drawn wires.
BVR{sub c}I{sub c} observations and analyses on V2421 Cygni, a precontact W UMa binary
Energy Technology Data Exchange (ETDEWEB)
Samec, R. G.; Shebs, Travis S. [Astronomy Group, Physics and Engineering Department, Bob Jones University, 1700 Wade Hampton Boulevard, Greenville, SC 29614 (United States); Faulkner, D. R. [University of South Carolina, Lancaster, 476 Hubbard Drive, Lancaster, SC 29720 (United States); Van Hamme, W. [Physics Department, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States); Mathis, R. F. [Global Research Technology Corporation, Camarillo, CA 92562 (United States)
2014-01-01
We present the first precision BVRI light curves, synthetic light curve solutions, and a period study for the high amplitude solar type binary, V2421 Cygni. The light curves have the appearance of an Algol (EA) type; however, it is made up of dwarf solar type components in a detached mode with a period of only 0.6331 days with an amplitude of about a full magnitude, i.e., it is a precontact W UMa binary. Flare-like disruptions occur in the light curves following the primary and secondary eclipses possibly due to the line-of-sight track of a gas stream. An associated stream spot and splash spot cause bright equatorial spots on the stellar surface of the primary star. The more massive star is the gainer, making this system a classic, albeit dwarf, Algol.
Fourier Series and Elliptic Functions
Fay, Temple H.
2003-01-01
Non-linear second-order differential equations whose solutions are the elliptic functions "sn"("t, k"), "cn"("t, k") and "dn"("t, k") are investigated. Using "Mathematica", high precision numerical solutions are generated. From these data, Fourier coefficients are determined yielding approximate formulas for these non-elementary functions that are…
Fourier Lucas-Kanade algorithm.
Lucey, Simon; Navarathna, Rajitha; Ashraf, Ahmed Bilal; Sridharan, Sridha
2013-06-01
In this paper, we propose a framework for both gradient descent image and object alignment in the Fourier domain. Our method centers upon the classical Lucas & Kanade (LK) algorithm where we represent the source and template/model in the complex 2D Fourier domain rather than in the spatial 2D domain. We refer to our approach as the Fourier LK (FLK) algorithm. The FLK formulation is advantageous when one preprocesses the source image and template/model with a bank of filters (e.g., oriented edges, Gabor, etc.) as 1) it can handle substantial illumination variations, 2) the inefficient preprocessing filter bank step can be subsumed within the FLK algorithm as a sparse diagonal weighting matrix, 3) unlike traditional LK, the computational cost is invariant to the number of filters and as a result is far more efficient, and 4) this approach can be extended to the Inverse Compositional (IC) form of the LK algorithm where nearly all steps (including Fourier transform and filter bank preprocessing) can be precomputed, leading to an extremely efficient and robust approach to gradient descent image matching. Further, these computational savings translate to nonrigid object alignment tasks that are considered extensions of the LK algorithm, such as those found in Active Appearance Models (AAMs).
Fourier Analysis of Musical Intervals
LoPresto, Michael C.
2008-01-01
Use of a microphone attached to a computer to capture musical sounds and software to display their waveforms and harmonic spectra has become somewhat commonplace. A recent article in "The Physics Teacher" aptly demonstrated the use of MacScope in just such a manner as a way to teach Fourier analysis. A logical continuation of this project is to…
Ji, Chenglong; Wu, Huifeng; Wei, Lei; Zhao, Jianmin
2014-12-01
Tetrabromobisphenol A (TBBPA) accounts for the largest production of brominated flame-retardants (BFRs) along the Laizhou Bay in China and is the most widely used BFR in industrial products. It can induce diverse toxicities including hepatotoxicity, nephrotoxicity, neurotoxicity and endocrine disrupting effects in mammalian and fish models. In this work, we applied iTRAQ-based proteomics to investigate the gender-specific responses in mussel Mytilus galloprovincialis to TBBPA. Thirty-one proteins were differentially expressed in hepatopancreas between male and female mussels, which clearly indicated the biological differences between male and female mussels at the protein level. After exposure of TBBPA (18.4 nmol/L) for one month, a total of 60 proteins were differentially expressed in response to the TBBPA treatment in mussel hepatopancreas, among which 33 and 29 proteins were significantly altered in TBBPA-treated male and female mussel samples, respectively. Only two of the 60 proteins were commonly altered in both male and female mussel samples exposed to TBBPA. Based on KEGG analysis, these differentially expressed proteins of TBBPA-induced effects were assigned to several groups, including cytoskeleton, reproduction and development, metabolism, signal transduction, gene expression, stress response and apoptosis. Overall, results indicated that TBBPA exposure could induce apoptosis, oxidative and immune stresses and disruption in energy, protein and lipid metabolisms in both male and female mussels with different mechanisms. This work suggested that the gender differences should be considered in ecotoxicoproteomics.
Grossberg, S E; Kawade, Y; Kohase, M; Yokoyama, H; Finter, N
2001-09-01
The highly specific ability of antibodies to inhibit the biologic activity of cytokines or other therapeutic proteins is widely used in research and a subject of increasing clinical importance. The need exists for a standardized approach to the reporting of neutralizing antibody potency soundly based on theoretical and practical considerations and tested by experimental data. Pursuant to the original studies of Kawade on the theoretical and functional aspects of neutralization of interferons (IFN), experimental data were obtained by different laboratories employing varied methodology to address two hypotheses concerning the nature of IFN neutralization reactions, based on a derived formula that allows expression of neutralizing power as the reduction of 10 laboratory units (LU)/ml to 1 LU/ml, the end point of most bioassays. Two hypotheses are posed: (1) antibody acts to neutralize a fixed amount of biologically active IFN molecules, or (2) antibody reduces IFN activity in a set ratio of added/residual biologically active IFN. The first, or fixed amount, hypothesis relates to the reactivity of high-affinity antibodies neutralizing equimolar amounts of antigen, whereas the second, or constant proportion, hypothesis postulates a reduction in the ratio of total added IFN to residual active IFN molecules, such as a low-affinity antibody might exhibit. Analyses of data of the neutralization of IFN-alpha and IFN-beta are presented, employing human polyclonal antibodies and murine monoclonal antibodies (mAb). The theoretical constructs of Kawade are extended in the Appendix and correlated with new experimental data in the text. The data clearly indicate that the low-antibody affinity, constant proportion hypothesis, rather than the high-antibody affinity, fixed amount hypothesis, is applicable, if the bioassay is sensitive to IFN. The findings presented here and in the following paper (pp. 743-755, this issue) taken together provide the basis for a standardized method of
Fourier analysis for rotating-element ellipsometers.
Cho, Yong Jai; Chegal, Won; Cho, Hyun Mo
2011-01-15
We introduce a Fourier analysis of the waveform of periodic light-irradiance variation to capture Fourier coefficients for multichannel rotating-element ellipsometers. In this analysis, the Fourier coefficients for a sample are obtained using a discrete Fourier transform on the exposures. The analysis gives a generic function that encompasses the discrete Fourier transform or the Hadamard transform, depending on the specific conditions. Unlike the Hadamard transform, a well-known data acquisition method that is used only for conventional multichannel rotating-element ellipsometers with line arrays with specific readout-mode timing, this Fourier analysis is applicable to various line arrays with either nonoverlap or overlap readout-mode timing. To assess the effects of the novel Fourier analysis, the Fourier coefficients for a sample were measured with a custom-built rotating-polarizer ellipsometer, using this Fourier analysis with various numbers of scans, integration times, and rotational speeds of the polarizer.
Directory of Open Access Journals (Sweden)
Yun Zhong
Full Text Available Root samples of 'Sanhu' red tangerine trees infected with and without Candidatus Liberibacter asiaticus (CLas were collected at 50 days post inoculation and subjected to RNA-sequencing and isobaric tags for relative and absolute quantification (iTRAQ to profile the differentially expressed genes (DEGs and proteins (DEPs, respectively. Quantitative real-time PCR was subsequently used to confirm the expression of 16 selected DEGs. Results showed that a total of 3956 genes and 78 proteins were differentially regulated by HLB-infection. Among the most highly up-regulated DEPs were sperm specific protein 411, copper ion binding protein, germin-like proteins, subtilisin-like proteins and serine carboxypeptidase-like 40 proteins whose transcript levels were concomitantly up-regulated as shown by RNA-seq data. Comparison between our results and those of the previously reported showed that known HLB-modulated biological pathways including cell-wall modification, protease-involved protein degradation, carbohydrate metabolism, hormone synthesis and signaling, transcription activities, and stress responses were similarly regulated by HLB infection but different or root-specific changes did exist. The root unique changes included the down-regulation in genes of ubiquitin-dependent protein degradation pathway, secondary metabolism, cytochrome P450s, UDP-glucosyl transferases and pentatricopeptide repeat containing proteins. Notably, nutrient absorption was impaired by HLB-infection as the expression of the genes involved in Fe, Zn, N and P adsorption and transportation were significantly changed. HLB-infection induced some cellular defense responses but simultaneously reduced the biosynthesis of the three major classes of secondary metabolites, many of which are known to have anti-pathogen activities. Genes involved in callose deposition were up-regulated whereas those involved in callose degradation were also up-regulated, indicating that the sieve tube
Directory of Open Access Journals (Sweden)
M. Schröder
2012-09-01
Full Text Available The "European Organisation for the Exploitation of Meteorological Satellites" (EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF aims at the provision and sound validation of well documented Climate Data Records (CDRs in sustained and operational environments. In this study, a total column water vapour (WVPA climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I, a climatology of WVPA has been generated within the Hamburg Ocean-Atmosphere Fluxes and Parameters from Satellite (HOAPS framework. Within a research and operation transition activity the HOAPS data and operations capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, kriging, has been developed and applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses and from the Japan Meteorological Agency (JMA-JRA. This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m^{−2}. The absolute bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m^{−2}. For the period 1991–2006, the root mean square error (RMSE to both reanalysis is approximately 2 kg m^{−2}. As SSM/I WVPA and radiances are assimilated in JMA and all
Directory of Open Access Journals (Sweden)
M. Schröder
2013-03-01
Full Text Available The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF aims at the provision and sound validation of well documented Climate Data Records (CDRs in sustained and operational environments. In this study, a total column water vapour path (WVPA climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I, a climatology of WVPA has been generated within the Hamburg Ocean–Atmosphere Fluxes and Parameters from Satellite (HOAPS framework. Within a research and operation transition activity the HOAPS data and operation capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, namely kriging, has been applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses and from the Japan Meteorological Agency (JMA–JRA. This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m−2. The absolute value of the bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m−2. For the period 1991–2006, the root mean square error (RMSE for both reanalyses is approximately 2 kg m−2. As SSM/I WVPA and radiances are assimilated into JMA and all ECMWF analyses and
Fourier series with the continuous primitive integral
Talvila, Erik
2011-01-01
Fourier series are considered on the one-dimensional torus for the space of periodic distributions that are the distributional derivative of a continuous function. This space of distributions is denoted $\\alext$ and is a Banach space under the Alexiewicz norm, $\\|f\\|_\\T =\\sup_{|I|\\leq 2\\pi}|\\int_I f|$, the supremum being taken over intervals of length not exceeding $2\\pi$. It contains the periodic functions integrable in the sense of Lebesgue and Henstock-Kurzweil. Many of the properties of $L^1$ Fourier series continue to hold for this larger space, with the $L^1$ norm replaced by the Alexiewicz norm. The Riemann-Lebesgue lemma takes the form $\\fhat(n)=o(n)$ as $|n|\\to\\infty$. The convolution is defined for $f\\in\\alext$ and $g$ a periodic function of bounded variation. The convolution commutes with translations and is commutative and associative. There is the estimate $\\|f\\ast g\\|_\\infty\\leq \\|f\\|_\\T \\|g\\|_\\bv$. For $g\\in L^1(\\T)$, $\\|f\\ast g\\|_\\T\\leq \\|f\\|_\\T \\|g\\|_1$. As well, $\\widehat{f\\ast g}(n)=\\fhatn ...
On localization for double Fourier series.
Goffman, C; Waterman, D
1978-02-01
The localization theorems for Fourier series of functions of a single variable are classical and easy to prove. The situation is different for Fourier series of functions of several variables, even if one restricts consideration to rectangular, in particular square, partial sums. We show that the answer to the problem can be obtained by considering the notion of generalized bounded variation, which we introduced. Given a nondecreasing sequence {lambda(n)} of positive numbers such that Sigma 1/lambda(n) diverges, a function g defined on an interval I of R(1) is said to be of Lambda-bounded variation (LambdaBV) if Sigma|g(a(n)) - g(b(n))|/lambda(n) converges for every sequence of nonoverlapping intervals (a(n), b(n)) [unk]I. If lambda(n) = n, we say that g is of harmonic bounded variation (HBV). The definition suitably modified can be extended to functions of several variables. We show that in the case of two variables the localization principle holds for rectangular partial sums if LambdaBV = HBV, and that if LambdaBV is not contained in HBV, then the localization principle does not hold for LambdaBV even in the case of square partial sums.
Research progress of the fractional Fourier transform in signal processing
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The fractional Fourier transform is a generalization of the classical Fourier transform, which is introduced from the mathematic aspect by Namias at first and has many applications in optics quickly. Whereas its potential appears to have remained largely unknown to the signal processing community until 1990s. The fractional Fourier transform can be viewed as the chirp-basis expansion directly from its definition, but essentially it can be interpreted as a rotation in the time-frequency plane, i.e. the unified time-frequency transform. With the order from 0 increasing to 1, the fractional Fourier transform can show the characteristics of the signal changing from the time domain to the frequency domain. In this research paper, the fractional Fourier transform has been comprehensively and systematically treated from the signal processing point of view. Our aim is to provide a course from the definition to the applications of the fractional Fourier transform, especially as a reference and an introduction for researchers and interested readers.
Energy Technology Data Exchange (ETDEWEB)
Christl, Marcus, E-mail: mchristl@ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Casacuberta, Nuria; Lachner, Johannes; Maxeiner, Sascha; Vockenhuber, Christof; Synal, Hans-Arno [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Goroncy, Ingo; Herrmann, Jürgen [Bundesamt für Seeschifffahrt und Hydrographie, Hamburg (Germany); Daraoui, Abdelouahed; Walther, Clemens; Michel, Rolf [Institut für Radioökologie und Strahlenschutz, Leibniz Universität Hannover (Germany)
2015-10-15
Compact, low energy accelerator mass spectrometry (AMS) has evolved over the past years as one of the most sensitive, selective, and robust techniques for the analysis of heavy and long lived radionuclides. In this study, we will first focus on the analytical capabilities of the compact AMS system TANDY, mainly for {sup 236}U analyses, and then present a new dual tracer approach, that combines {sup 129}I and {sup 236}U. The measured {sup 129}I/{sup 236}U ratios of samples collected in the North Sea in 2009 are in reasonable agreement with the expectations from documented or estimated releases from the two major nuclear reprocessing plants located at Sellafield (GB) and La Hague (F), suggesting that the {sup 129}I/{sup 236}U ratio can be used as a water mass tag in the North Atlantic region. However, our results indicate that, in contrast to {sup 129}I, additional contributions of bomb produced {sup 236}U cannot be neglected in the North Sea region. This complicates the simple and straight forward use of the {sup 129}I/{sup 236}U ratio as a quantitative tool for the calculation of transport times of North Sea water in the Arctic Ocean.
Directory of Open Access Journals (Sweden)
Tiina Sepp
2012-12-01
Full Text Available In this article I am going to analyse my experiences of fieldwork and discuss the role of the researcher in the process of data collection. I will approach problems arising during folkloristic fieldwork and the focus will be on researching belief narrative in personal experience stories. A lot has been written about fieldwork and in this article I am going to add my thoughts on topics that have already been discussed in self-critical reflexive style by several scholars: the different roles of the researcher and the problematic interactional relationship between researcher and informant; power relationships in an interview situation; combining emic and etic perspectives in researching; being ambivalent about which reality we really belong to. I am also going to raise some issues that have to date not been discussed much: the effect of the researcher’s gender on the process of fieldwork; stigmatisation of the supernatural; using the researcher’s own memorates to elicit belief statements from his or her informants; dealing with ‘difficult’ informants. Against the background of the above-mentioned topics lies the liminality of the researcher – while in the field we are in a state of liminality that Victor Turner described when talking about pilgrims and neophytes.Apart from discussing fieldwork-related problems, I am also going to describe some expressions of vernacular religion and contemporary spirituality on the Camino de Santiago and in Glastonbury.
Directory of Open Access Journals (Sweden)
Christine Petersen
2014-11-01
Full Text Available Artiklen tager udgangspunkt i kampagnefilmen ”Tænk. Hvis det er dig”, som var en del af den branding-, vejlednings- og rekrutteringskampagne, som Aarhus Universitet lancerede i 2012, og på baggrund af en analyse af filmens komposition samt billed- og lydside undersøger artiklen, hvordan kampagnefilmen opbygger en handlingsmæssig struktur, som realiserer en grundlæggende metaforisk forståelse af ’uddannelse som en rejse’. Ved hjælp af George Lakoff og Mark Johnsons metaforteori undersøges den anvendte metafors beskaffenhed, struktur og betydning(er, og i artiklen argumenterer vi for en tolkning af den anvendte metafor som ’uddannelse som en moderne dannelsesrejse’. Lakoff og Johnsons metaforteori, som tager udgangspunkt i sproglige tegn, vil i denne artikel blive anvendt på analysen af visuelle tegn, og dermed ønsker vi at demonstrere, at et oprindeligt sproglig-tekstuelt baseret metaforbegreb også kan bidrage til en bedre forst.else af visuel-fi lmiske narrative teknikker.
Firnkorn, Daniel; Merker, Sebastian; Ganzinger, Matthias; Muley, Thomas; Knaup, Petra
2016-01-01
In medical science, modern IT concepts are increasingly important to gather new findings out of complex diseases. Data Warehouses (DWH) as central data repository systems play a key role by providing standardized, high-quality and secure medical data for effective analyses. However, DWHs in medicine must fulfil various requirements concerning data privacy and the ability to describe the complexity of (rare) disease phenomena. Here, i2b2 and tranSMART are free alternatives representing DWH solutions especially developed for medical informatics purposes. But different functionalities are not yet provided in a sufficient way. In fact, data import and export is still a major problem because of the diversity of schemas, parameter definitions and data quality which are described variously in each single clinic. Further, statistical analyses inside i2b2 and tranSMART are possible, but restricted to the implemented functions. Thus, data export is needed to provide a data basis which can be directly included within statistics software like SPSS and SAS or data mining tools like Weka and RapidMiner. The standard export tools of i2b2 and tranSMART are more or less creating a database dump of key-value pairs which cannot be used immediately by the mentioned tools. They need an instance-based or a case-based representation of each patient. To overcome this lack, we developed a concept called Generic Case Extractor (GCE) which pivots the key-value pairs of each clinical fact into a row-oriented format for each patient sufficient to enable analyses in a broader context. Therefore, complex pivotisation routines where necessary to ensure temporal consistency especially in terms of different data sets and the occurrence of identical but repeated parameters like follow-up data. GCE is embedded inside a comprehensive software platform for systems medicine.
Thermal Analyse sof Cross-Linked Polyethylene
Directory of Open Access Journals (Sweden)
Radek Polansky
2007-01-01
Full Text Available The paper summarizes results obtained during the structural analyses measurements (Differential Scanning Calorimetry DSC, Thermogravimetry TG, Thermomechanical analysis TMA and Fourier transform infrared spectroscopy FT-IR. The samples of cross-linked polyethylene cable insulation were tested via these analyses. The DSC and TG were carried out using simultaneous thermal analyzer TA Instruments SDT Q600 with connection of Fourier transform infrared spectrometer Nicolet 380. Thermomechanical analysis was carried out by TMA Q400EM TA Instruments apparatus.
Boysen, Christian; Munch-Petersen, Mette Marie
2008-01-01
Resumé Denne rapport omhandler den danske mikrobryggeribranche med særlig vægt på GourmetBryggeriet A/S i Roskilde. Gennem en PEST-analyse og Michael E. Porters teori om markedsanalyse og konkurrencestrategi, undersøges GourmetBryggeriets nuværende og potentielle, fremtidige markedsposition. Mikrobryggeribranchen undersøges hovedsagligt gennem Porters Five Forces med særlig vægt på de tre kræfter; intern konkurrence, potentielle indtrædere og kunder. Det har vist sig, at mikrobryggeribranc...
Barder, Timothy E
2006-01-25
The treatment of bis(2-(dicyclohexylphosphino)-2',6'-dimethoxybiphenyl)PdCl2 with AgBF4 produces an air-stable phosphine/arene-ligated Pd(I) dimer with two seemingly identical Pd-arene interactions by X-ray crystallography. However, NMR and theoretical electron topographical analyses of this complex distinguish between these two interactions. One interaction is classified as an arenium-like complex, while the other is classified as a pi-interaction. Additionally, this complex is a suitable precatalyst for high yielding Suzuki-Miyaura coupling reactions in short reaction times.
Motion-corrected Fourier ptychography
Bian, Liheng; Guo, Kaikai; Suo, Jinli; Yang, Changhuei; Chen, Feng; Dai, Qionghai
2016-01-01
Fourier ptychography (FP) is a recently proposed computational imaging technique for high space-bandwidth product imaging. In real setups such as endoscope and transmission electron microscope, the common sample motion largely degrades the FP reconstruction and limits its practicability. In this paper, we propose a novel FP reconstruction method to efficiently correct for unknown sample motion. Specifically, we adaptively update the sample's Fourier spectrum from low spatial-frequency regions towards high spatial-frequency ones, with an additional motion recovery and phase-offset compensation procedure for each sub-spectrum. Benefiting from the phase retrieval redundancy theory, the required large overlap between adjacent sub-spectra offers an accurate guide for successful motion recovery. Experimental results on both simulated data and real captured data show that the proposed method can correct for unknown sample motion with its standard deviation being up to 10% of the field-of-view scale. We have released...
Fourier Analysis of Blazar Variability
Finke, Justin D
2014-01-01
Blazars display strong variability on multiple timescales and in multiple radiation bands. Their variability is often characterized by power spectral densities (PSDs) and time lags plotted as functions of the Fourier frequency. We develop a new theoretical model based on the analysis of the electron transport (continuity) equation, carried out in the Fourier domain. The continuity equation includes electron cooling and escape, and a derivation of the emission properties includes light travel time effects associated with a radiating blob in a relativistic jet. The model successfully reproduces the general shapes of the observed PSDs and predicts specific PSD and time lag behaviors associated with variability in the synchrotron, synchrotron self-Compton (SSC), and external Compton (EC) emission components, from sub-mm to gamma-rays. We discuss applications to BL Lacertae objects and to flat-spectrum radio quasars (FSRQs), where there are hints that some of the predicted features have already been observed. We a...
From Fourier analysis to wavelets
Gomes, Jonas
2015-01-01
This text introduces the basic concepts of function spaces and operators, both from the continuous and discrete viewpoints. Fourier and Window Fourier Transforms are introduced and used as a guide to arrive at the concept of Wavelet transform. The fundamental aspects of multiresolution representation, and its importance to function discretization and to the construction of wavelets is also discussed. Emphasis is given on ideas and intuition, avoiding the heavy computations which are usually involved in the study of wavelets. Readers should have a basic knowledge of linear algebra, calculus, and some familiarity with complex analysis. Basic knowledge of signal and image processing is desirable. This text originated from a set of notes in Portuguese that the authors wrote for a wavelet course on the Brazilian Mathematical Colloquium in 1997 at IMPA, Rio de Janeiro.
Compact Microwave Fourier Spectrum Analyzer
Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry
2009-01-01
A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.
Fourier's Law in Quantum Mechanics
Seligman, Thomas H
2010-01-01
We derive Fourier's law for a completely coherent quantum system coupled locally to two heat baths at different temperatures. We solve the master equation to first order in the temperature difference. We show that the heat conductance can be expressed as a thermodynamic equilibrium coefficient taken at some intermediate temperature. We use that expression to show that for temperatures large compared to the mean level spacing of the system, the heat conductance is inversely proportional to the length of the system.
Subharmonic Fourier domain mode locking.
Eigenwillig, Christoph M; Wieser, Wolfgang; Biedermann, Benjamin R; Huber, Robert
2009-03-15
We demonstrate a subharmonically Fourier domain mode-locked wavelength-swept laser source with a substantially reduced cavity fiber length. In contrast to a standard Fourier domain mode-locked configuration, light is recirculated repetitively in the delay line with the optical bandpass filter used as switch. The laser has a fundamental optical round trip frequency of 285 kHz and can be operated at integer fractions thereof (subharmonics). Sweep ranges up to 95 nm full width centred at 1317 nm are achieved at the 1/5th subharmonic. A maximum sensitivity of 116 dB and an axial resolution of 12 microm in air are measured at an average sweep power of 12 mW. A sensitivity roll-off of 11 dB over 4 mm and 25 dB over 10 mm is observed and optical coherence tomography imaging is demonstrated. Besides the advantage of a reduced fiber length, subharmonic Fourier domain mode locking (shFDML) enables simple scaling of the sweep speed by extracting light from the delay part of the resonator. A sweep rate of 570 kHz is achieved. Characteristic features of shFDML operation, such as power leakage during fly-back and cw breakthrough, are investigated.
A More Accurate Fourier Transform
Courtney, Elya
2015-01-01
Fourier transform methods are used to analyze functions and data sets to provide frequencies, amplitudes, and phases of underlying oscillatory components. Fast Fourier transform (FFT) methods offer speed advantages over evaluation of explicit integrals (EI) that define Fourier transforms. This paper compares frequency, amplitude, and phase accuracy of the two methods for well resolved peaks over a wide array of data sets including cosine series with and without random noise and a variety of physical data sets, including atmospheric $\\mathrm{CO_2}$ concentrations, tides, temperatures, sound waveforms, and atomic spectra. The FFT uses MIT's FFTW3 library. The EI method uses the rectangle method to compute the areas under the curve via complex math. Results support the hypothesis that EI methods are more accurate than FFT methods. Errors range from 5 to 10 times higher when determining peak frequency by FFT, 1.4 to 60 times higher for peak amplitude, and 6 to 10 times higher for phase under a peak. The ability t...
An introduction to Fourier series and integrals
Seeley, Robert T
2006-01-01
This compact guide emphasizes the relationship between physics and mathematics, introducing Fourier series in the way that Fourier himself used them: as solutions of the heat equation in a disk. 1966 edition.
Directory of Open Access Journals (Sweden)
Kuo-Chin Hung
2012-01-01
Full Text Available Patients on long-term dialysis may develop secondary hyperparathyroidism (SHPT with increased serum concentrations of bone resorption markers such as the cross-linked N-telopeptide of type I collagen (NTX and type-5b tartrate-resistant acid phosphatase (TRAP. When SHPT proves refractory to treatment, parathyroidectomy (PTX may be needed. Renal patients on maintenance HD who received PTX for refractory SHPT (n=23 or who did not develop refractory SHPT (control subjects; n=25 were followed prospectively for 4 weeks. Serum intact parathyroid hormone (iPTH, NTX, TRAP, and bone alkaline phosphatase (BAP concentrations were measured serially and correlation analyses were performed. iPTH values decreased rapidly and dramatically. BAP values increased progressively with peak increases observed at 2 weeks after surgery. NTX and TRAP values decreased concurrently and progressively through 4 weeks following PTX. A significant correlation between TRAP and NTX values was observed before PTX but not at 4 weeks after PTX. Additionally, the fractional changes in serum TRAP were larger than those in serum NTX at all times examined after PTX. Serum iPTH, TRAP, and NTX values declined rapidly following PTX for SHPT. Serum TRAP values declined to greater degrees than serum NTX values throughout the 4-week period following PTX.
Gupta, Radhey S; Gao, Beile
2009-02-01
The species of Clostridium comprise a very heterogeneous assemblage of bacteria that do not form a phylogenetically coherent group. It has been proposed previously that only a subset of the species of Clostridium that form a distinct cluster in the 16S rRNA tree (cluster I) should be regarded as the true representatives of the genus Clostridium (i.e. Clostridium sensu stricto). However, this cluster is presently defined only in phylogenetic terms, and no biochemical, molecular or phenotypic characteristic is known that is unique to species from this cluster. We report here phylogenomic and comparative analyses based on sequenced clostridial genomes in an attempt to bridge this gap and to clarify the evolutionary relationships among species of clostridia. In phylogenetic trees for species of clostridia based on concatenated sequences for 37 highly conserved proteins, the species of Clostridium cluster I formed a strongly supported clade that was separated from all other clostridia by a long branch. Several other Clostridium species that are not part of this cluster grouped reliably with other species of clostridia in a number of well-resolved clades. Our comparative genomic analyses have identified three conserved indels in three highly conserved proteins (a 4 aa insert in DNA gyrase A, a 1 aa deletion in ATP synthase beta subunit and a 1 aa insert in ribosomal protein S2) that are unique to the species of Clostridium cluster I and are not found in any other bacteria. blastp searches on various proteins in the genomes of Clostridium tetani E88 and Clostridium perfringens SM101 have also identified more than 10 proteins that are found uniquely in the cluster I species. These results provide evidence that the species of Clostridium cluster I not only are phylogenetically distinct but also share many unique molecular characteristics. These newly identified molecular markers provide useful tools to define and circumscribe the genus Clostridium sensu stricto in more
JCE Online: Interactive Fourier Transform Activities
Zielinski, Theresa Julia
1999-02-01
In our vigorous teaching of concepts and skills to students, we may cover (hide) more than we uncover, obscuring significant relationships between mathematical models and their associated chemical concepts with excessive mathematical derivations. To set the record straight, I find that mathematical treatments of physical phenomena are beautiful and elegant. Students should know from where the equations and simplifications leading to them arise. They should know the limits of the equations in order to use them properly. However, this can be the Siren's song. For example, the mathematical representation of the Fourier transform and its significance as presented in most texts are too brief to convey understanding to the typical undergraduate student. Furthermore, a few hand calculations would not permit deeper probing of the method and its intimate link to spectroscopy. The Fourier transform is a very good example of how symbolic equation software can help to uncover the science by making the mathematical manipulations easier and the mathematical concepts more accessible. The complete articles and Mathcad documents described in these abstracts are available from JCE Online at http://jchemed.chem.wisc.edu/JCEWWW/Columns/McadInChem/.
Fourier techniques in X-ray timing
M. van der Klis
1988-01-01
Basic principles of Fourier techniques often used in X-ray time series analysis are reviewed. The relation between the discrete Fourier transform and the continuous Fourier transform is discussed to introduce the concepts of windowing and aliasing. The relation is derived between the power spectrum
Barco, L; Mancin, M; Ruffa, M; Saccardin, C; Minorello, C; Zavagnin, P; Lettini, A A; Olsen, J E; Ricci, A
2012-11-01
Salmonella enterica 4,[5],12:i:- is a monophasic variant of S. Typhimurium. In the last decade, its prevalence rose sharply. Although S. 4,[5],12:i:- and S. Typhimurium are known to pose a considerable public health risk, there is no detailed information on the circulation of these serovars in Italy, particularly as far as veterinary isolates are concerned. For this reason, a data set of 877 strains isolated in the north-east of Italy from foodstuffs, animals and environment was analysed during 2005-2010. The Random Forests (RF) method was used to identify the most important epidemiological and phenotypic variables to show the difference between the two serovars. Both descriptive analysis and RF revealed that S. 4,[5],12:i:- is less heterogeneous than S. Typhimurium. RF highlighted that phage type was the most important variable to differentiate the two serovars. The most common phage types identified for S. 4,[5],12:i:- were DT20a, U311 and DT193. The same phage types were also found in S. Typhimurium isolates, although with a much lower prevalence. DT7 and DT120 were ascribed to the two serovars at comparable levels. DT104, DT2 and DT99 were ascribed exclusively to S. Typhimurium, and almost all the other phage types identified were more related to the latter serovar. Such data confirm that phage typing can provide an indication of the biphasic or monophasic state of the strains investigated and could therefore support serotyping results. However, phage typing cannot be used as the definitive method to differentiate the two serovars, as part of the phage types were detected for both serovars and, in particular, all phage types found for S. 4,[5],12:i- were found also for S. Typhimurium.
Directory of Open Access Journals (Sweden)
Rosat Séverine
2016-01-01
Full Text Available In the last few years, the performance of the cryogenic gravity instruments has been further improved by the development of a new generation of superconducting gravimeter (SG: the so-called iOSG which is a superconducting gravimeter designed for observatory purpose with a heavier sphere than previous SGs. The first iOSG (iOSG-024 has been installed in July 2015 at the LSSB low background noise underground research laboratory in Rustrel (France, funded by the EQUIPEX MIGA (Matter wave-laser based Interferometer Gravitation Antenna project and by the European FEDER 2006-2013 “PFM LSBB – Développement des qualités environnementales du LSBB”. This instrument is operational since September 2015. We present the first tidal analyses of the 7-month time-varying gravity records of this newly installed instrument as well as the calibration results performed by parallel FG5 absolute gravity measurements. We also show the performances of iOSG-024 in terms of noise levels in the seismic (in the millihertz frequency range band using a standardized procedure based on the computation of the residual power spectral densities over a quiet time period. The obtained noise levels are compared with other SG sites and with seismological reference noise models. The combination of the instrumental performance of the iOSG with the LSBB site properties makes this gravimetric station one of the quietest in the world, comparable to the lower sensor of the OSG-56 at BFO, at seismic frequencies.
A Fourier Optical Model for the Laser Doppler Velocimeter
DEFF Research Database (Denmark)
Lading, Lars
1972-01-01
The treatment is based on a fourier optical model. It is shown how the various configurations (i.e. ldquodifferential moderdquo and reference beam mode with both one and two incident beams) are incorporated in the model, and how it can be extended to three dimensions. The particles are represented...... filtering ability vanishes as the aperture size converges towards zero. The results based on fourier optics are compared with the rough estimates obtainable by using the "antenna formular" for heterodyning (ArΩr≈λ2)....
Joint spectrum of photon pairs measured by coincidence Fourier spectroscopy
Wasilewski, W; Kolenderski, P; Banaszek, K; Radzewicz, C; Wasilewski, Wojciech; Wasylczyk, Piotr; Kolenderski, Piotr; Banaszek, Konrad; Radzewicz, Czeslaw
2005-01-01
We propose and demonstrate a method for measuring the joint spectrum of photon pairs via Fourier spectroscopy. The biphoton spectral intensity is computed from a two-dimensional interferogram of coincidence counts. The method has been implemented for a type-I downconversion source using a pair of common-path Mach-Zender interferometers based on Soleil compensators. The experimental results agree well with calculated frequency correlations that take into account the effects of coupling into single-mode fibers. The Fourier method is advantageous over scanning spectrometry when detectors exhibit high dark count rates leading to dominant additive noise.
Aperture scanning Fourier ptychographic microscopy
Ou, Xiaoze; Chung, Jaebum; Horstmeyer, Roarke; Yang, Changhuei
2016-01-01
Fourier ptychographic microscopy (FPM) is implemented through aperture scanning by an LCOS spatial light modulator at the back focal plane of the objective lens. This FPM configuration enables the capturing of the complex scattered field for a 3D sample both in the transmissive mode and the reflective mode. We further show that by combining with the compressive sensing theory, the reconstructed 2D complex scattered field can be used to recover the 3D sample scattering density. This implementation expands the scope of application for FPM and can be beneficial for areas such as tissue imaging and wafer inspection. PMID:27570705
Novel Micro Fourier Transform Spectrometers
Institute of Scientific and Technical Information of China (English)
KONG Yan-mei; LIANG Jing-qiu; LIANG Zhong-zhu; WANG-Bo; ZHANG Jun
2008-01-01
The miniaturization of spectrometer opens a new application area with real-time and on-site measurements. The Fourier transform spectrometer(FTS) is much attractive considering its particular advantages among the approaches. This paper reviews the current status of micro FTS in worldwide and describes its developments; In addition, analyzed are the key problems in designing and fabricating FTS to be settled during the miniaturization. Finally, a novel model of micro FTS with no moving parts is proposed and analyzed, which may provide new concepts for the design of spectrometers.
Fourier-transform optical microsystems
Collins, S. D.; Smith, R. L.; Gonzalez, C.; Stewart, K. P.; Hagopian, J. G.; Sirota, J. M.
1999-01-01
The design, fabrication, and initial characterization of a miniature single-pass Fourier-transform spectrometer (FTS) that has an optical bench that measures 1 cm x 5 cm x 10 cm is presented. The FTS is predicated on the classic Michelson interferometer design with a moving mirror. Precision translation of the mirror is accomplished by microfabrication of dovetailed bearing surfaces along single-crystal planes in silicon. Although it is miniaturized, the FTS maintains a relatively high spectral resolution, 0.1 cm-1, with adequate optical throughput.
Fourier analysis and its applications
Folland, Gerald B
2009-01-01
This book presents the theory and applications of Fourier series and integrals, eigenfunction expansions, and related topics, on a level suitable for advanced undergraduates. It includes material on Bessel functions, orthogonal polynomials, and Laplace transforms, and it concludes with chapters on generalized functions and Green's functions for ordinary and partial differential equations. The book deals almost exclusively with aspects of these subjects that are useful in physics and engineering, and includes a wide variety of applications. On the theoretical side, it uses ideas from modern ana
JPL Fourier transform ultraviolet spectrometer
Cageao, R. P.; Friedl, R. R.; Sander, Stanley P.; Yung, Y. L.
1994-01-01
The Fourier Transform Ultraviolet Spectrometer (FTUVS) is a new high resolution interferometric spectrometer for multiple-species detection in the UV, visible and near-IR. As an OH sensor, measurements can be carried out by remote sensing (limb emission and column absorption), or in-situ sensing (long-path absorption or laser-induced fluorescence). As a high resolution detector in a high repetition rate (greater than 10 kHz) LIF system, OH fluorescence can be discriminated against non-resonant background emission and laser scatter, permitting (0, 0) excitation.
Fourier-Transform Infrared Spectrometer
Schindler, R. A.
1986-01-01
Fourier-transform spectrometer provides approximately hundredfold increase in luminosity at detector plane over that achievable with older instruments of this type. Used to analyze such weak sources as pollutants and other low-concentration substances in atmosphere. Interferometer creates fringe patterns on two distinct arrays of light detectors, which observe different wavelength bands. Objective lens focuses scene on image plane, which contains optical chopper. To make instrument less susceptible to variations in scene under observation, field and detector lenses focus entrance aperture, rather that image, onto detector array.
Fourier Transform Methods. Chapter 4
Kaplan, Simon G.; Quijada, Manuel A.
2015-01-01
This chapter describes the use of Fourier transform spectrometers (FTS) for accurate spectrophotometry over a wide spectral range. After a brief exposition of the basic concepts of FTS operation, we discuss instrument designs and their advantages and disadvantages relative to dispersive spectrometers. We then examine how common sources of error in spectrophotometry manifest themselves when using an FTS and ways to reduce the magnitude of these errors. Examples are given of applications to both basic and derived spectrophotometric quantities. Finally, we give recommendations for choosing the right instrument for a specific application, and how to ensure the accuracy of the measurement results..
DEFF Research Database (Denmark)
le Fevre Jakobsen, Bjarne
Publikationen indeholder øvematerialer, tekster, powerpointpræsentationer og handouts til undervisningsfaget Sproglig Metode og Analyse på BA og tilvalg i Dansk/Nordisk 2010-2011......Publikationen indeholder øvematerialer, tekster, powerpointpræsentationer og handouts til undervisningsfaget Sproglig Metode og Analyse på BA og tilvalg i Dansk/Nordisk 2010-2011...
FFTW: Fastest Fourier Transform in the West
Frigo, Matteo; Johnson, Steven G.
2012-01-01
FFTW is a C subroutine library for computing the discrete Fourier transform (DFT) in one or more dimensions, of arbitrary input size, and of both real and complex data (as well as of even/odd data, i.e. the discrete cosine/sine transforms or DCT/DST). Benchmarks performed on a variety of platforms show that FFTW's performance is typically superior to that of other publicly available FFT software, and is even competitive with vendor-tuned codes. In contrast to vendor-tuned codes, however, FFTW's performance is portable: the same program will perform well on most architectures without modification. The FFTW library is required by other codes such as StarCrash and Hammurabi.
Denoise in the pseudopolar grid Fourier space using exact inverse pseudopolar Fourier transform
Wei, Fan Jun
2015-01-01
In this paper I show a matrix method to calculate the exact inverse pseudopolar grid Fourier transform, and use this transform to do noise removals in the k space of pseudopolar grids. I apply the Gaussian filter to this pseudopolar grid and find the advantages of the noise removals are very excellent by using pseudopolar grid, and finally I show the Cartesian grid denoise for comparisons. The results present the signal to noise ratio and the variance are much better when doing noise removals in the pseudopolar grid than the Cartesian grid. The noise removals of pseudopolar grid or Cartesian grid are both in the k space, and all these noises are added in the real space.
Crow, Stephen M; Hartman, Sandra J; Mahesh, Sathiadev; McLendon, Christy L; Henson, Steve W; Jacques, Paul
2008-01-01
The shortage of nurses in the United States remains a persistent problem. Faced with this reality, nursing programs in colleges and universities continue to struggle to expand enrollment levels to meet the spiraling demand. This research uses familiar tools in strategic management: the strengths, weaknesses, opportunities, and threats (SWOT) analysis and stakeholder analysis as initial steps to draw more students to the profession of nursing. In a 2-round modified Delphi survey, chief administrators of schools of nursing identify the main SWOT of schools of nursing and the important internal and external stakeholders that influence nursing school success. The authors of the research suggest ways to use that knowledge to increase the enrollment level of nursing students. Part I of this research focuses on the SWOT analyses.
Pointwise convergence of Fourier series
Arias de Reyna, Juan
2002-01-01
This book contains a detailed exposition of Carleson-Hunt theorem following the proof of Carleson: to this day this is the only one giving better bounds. It points out the motivation of every step in the proof. Thus the Carleson-Hunt theorem becomes accessible to any analyst.The book also contains the first detailed exposition of the fine results of Hunt, Sjölin, Soria, etc on the convergence of Fourier Series. Its final chapters present original material. With both Fefferman's proof and the recent one of Lacey and Thiele in print, it becomes more important than ever to understand and compare these two related proofs with that of Carleson and Hunt. These alternative proofs do not yield all the results of the Carleson-Hunt proof. The intention of this monograph is to make Carleson's proof accessible to a wider audience, and to explain its consequences for the pointwise convergence of Fourier series for functions in spaces near $äcal Lü^1$, filling a well-known gap in the literature.
Dantas, José L; Camata, Thiago V; Brunetto, Maria A C; Moraes, Antonio C; Abrão, Taufik; Altimari, Leandro R
2010-01-01
Frequency domain analyses of changes in electromyographic (EMG) signals over time are frequently used to assess muscle fatigue. Fourier based approaches are typically used in these analyses, yet Fourier analysis assumes signal stationarity, which is unlikely during dynamic contractions. Wavelet based methods of signal analysis do not assume stationarity and may be more appropriate for joint time-frequency domain analysis. The purpose of this study was to compare Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT) in assessing muscle fatigue in isometric and dynamic exercise. The results of this study indicate that CWT and STFT analyses give similar fatigue estimates (slope of median frequency) in isometric and dynamic exercise (P>0.05). However, the results of the variance was lower for both types of exercise in CWT compared to STFT (P signal analysis using STFT. Thus, the stationarity assumption may not be the sole factor responsible for affecting the Fourier based estimates.
Scaled Fractional Fourier Transform for Partially Coherent Beams
Institute of Scientific and Technical Information of China (English)
蔡阳健; 林强
2003-01-01
The definition of scaled fractional Fourier transform (SFRT) is extended to partially coherent beams based directly on the cross-spectral density. Based on this formula, an equivalent tensor ABCD law for the SFRT of partially coherent twisted anisotropic Gaussian-Schell model beams is derived. The derived formulae provide a powerful tool for analysing and calculating the SFRT of partially coherent beams. An application example is provided.
Prediction of Tide Height Using the Discrete Fourier Transform
Directory of Open Access Journals (Sweden)
Md. Towhiduzzaman
2016-12-01
Full Text Available In this study, I have investigated some aspects of astronomical tide and predicted tide time and height by different methods. This thesis deals with the prediction of height and time for both high and low waters of the ports set up in several places by discrete Fourier transform. I computed the tide height using Discrete Fourier Transform (DFT. The results are found to be in an agreement with the predicted data of others. By this work, we can predict the tide height of overall stations if the sample observed data are available for any kind of stations. I think that my work could be helpful to predict the tides over all stations where the observed data are available.
Quantum Fourier transform in computational basis
Zhou, S. S.; Loke, T.; Izaac, J. A.; Wang, J. B.
2017-03-01
The quantum Fourier transform, with exponential speed-up compared to the classical fast Fourier transform, has played an important role in quantum computation as a vital part of many quantum algorithms (most prominently, Shor's factoring algorithm). However, situations arise where it is not sufficient to encode the Fourier coefficients within the quantum amplitudes, for example in the implementation of control operations that depend on Fourier coefficients. In this paper, we detail a new quantum scheme to encode Fourier coefficients in the computational basis, with fidelity 1 - δ and digit accuracy ɛ for each Fourier coefficient. Its time complexity depends polynomially on log (N), where N is the problem size, and linearly on 1/δ and 1/ɛ . We also discuss an application of potential practical importance, namely the simulation of circulant Hamiltonians.
The multiple-parameter fractional Fourier transform
Institute of Scientific and Technical Information of China (English)
LANG Jun; TAO Ran; RAN QiWen; WANG Yue
2008-01-01
The fractional Fourier transform (FRFT) has multiplicity, which is intrinsic in frac-tional operator. A new source for the multiplicity of the weight-type fractional Fou-rier transform (WFRFT) is proposed, which can generalize the weight coefficients of WFRFT to contain two vector parameters MN,∈ZM. Therefore a generalized frac-tional Fourier transform can be defined, which is denoted by the multiple-parameter fractional Fourier transform (MPFRFT). It enlarges the multiplicity of the FRFT, which not only includes the conventional FRFT and general multi-fractional Fourier transform as special cases, but also introduces new fractional Fourier transforms. It provides a unified framework for the FRFT, and the method is also available for fractionalizing other linear operators. In addition, numerical simulations of the MPFRFT on the Hermite-Gaussian and rectangular functions have been performed as a simple application of MPFRFT to signal processing.
The Fourier Transform on Quantum Euclidean Space
Directory of Open Access Journals (Sweden)
Kevin Coulembier
2011-05-01
Full Text Available We study Fourier theory on quantum Euclidean space. A modified version of the general definition of the Fourier transform on a quantum space is used and its inverse is constructed. The Fourier transforms can be defined by their Bochner's relations and a new type of q-Hankel transforms using the first and second q-Bessel functions. The behavior of the Fourier transforms with respect to partial derivatives and multiplication with variables is studied. The Fourier transform acts between the two representation spaces for the harmonic oscillator on quantum Euclidean space. By using this property it is possible to define a Fourier transform on the entire Hilbert space of the harmonic oscillator, which is its own inverse and satisfies the Parseval theorem.
Oversampling analysis in fractional Fourier domain
Institute of Scientific and Technical Information of China (English)
ZHANG Feng; TAO Ran; WANG Yue
2009-01-01
Oversampling is widely used in practical applications of digital signal processing. As the fractional Fourier transform has been developed and applied in signal processing fields, it is necessary to consider the oversampling theorem in the fractional Fourier domain. In this paper, the oversampling theorem in the fractional Fourier domain is analyzed. The fractional Fourier spectral relation between the original oversampled sequence and its subsequences is derived first, and then the expression for exact reconstruction of the missing samples in terms of the subsequences is obtained. Moreover, by taking a chirp signal as an example, it is shown that, reconstruction of the missing samples in the oversampled signal Is suitable in the fractional Fourier domain for the signal whose time-frequency distribution has the minimum support in the fractional Fourier domain.
Kamga, Albert W; Behar, Fancoise; Hatcher, Patrick G
2014-05-01
Long chain fatty acids (LCFAs) are present in various natural samples and are easily detectable using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) in negative ion mode. The capability of the ESI-FT-ICR-MS for quantifying LCFAs was evaluated by performing a standard addition followed by an internal standard methodology to several kerogen extracts using n-C₂₀ fatty acid as standard. As the concentration of the standard increased, the magnitude of its peak (m/z 311.29525) increased linearly but with two separate slopes, leaving the entire mass spectra relatively unchanged, which shows evidence of reproducibility. Response factors of other LCFAs are obtained using a standard addition approach. We employed five LCFA standards (n-C₁₅, n-C₁₉, n-C₂₄, n-C₂₆, and n-C₃₀) with different carbon numbers. This allowed us to determine the response factor of all fatty acids (with carbon number between 15 and 30) by plotting the slope of each standard versus its carbon number. With the observed response factors and use of the internal standard, the concentrations of LCFAs in four kerogen extracts were measured by ESI-FT-ICR-MS and compared with those from GC-FID. The carbon number distribution obtained by ESI-FT-ICR-MS matched well the GC-FID distribution (5%–50%) with the exception of C₁₆ and C₁₈, considering that ESI-FT-ICR-MS does not differentiate between normal and branched LCFAs, whereas GC-FID does. This allows one to quantitatively compare samples with a relatively similar matrix for specific compounds such as LCFAs with no need of time-consuming derivatization procedures. Moreover, the calibration can be extended to higher carbon numbers with ESI-FT-ICR-MS, beyond the capabilities of GC/MS.
Chemical and topographical analyses of dentine surfaces after Carisolv treatment.
Arvidsson, Anna; Liedberg, Bo; Möller, Kenneth; Lyvén, Benny; Sellén, Annika; Wennerberg, Ann
2002-01-01
The aim of this study was to characterise the surface chemistry of cavities after chemomechanical caries excavation, and also to measure the surface topography after caries removal with Carisolv or burs, followed by acid etching. Fourier transform (FT)-Raman spectroscopy was used to study the relative amounts of organic material and minerals of sound enamel, dentine, and cavities, after caries excavation. Fourier transform infrared spectroscopy (FTIR) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used for detection of Carisolv substances (i.e. mainly sodium hypochlorite, amino acids, and the gelling agent carboxymethyl cellulose). In total, 19 carious and 11 sound extracted teeth were used for the chemical analyses. Topographic examination of 30 carious extracted teeth was performed with a contact profilometer. The relative amounts of organic material and minerals did not significantly differ between sound dentine and the cavities after caries removal with burs or Carisolv. The FTIR analyses indicated extremely small amounts of Carisolv substances at the cavity surface, but the LA-ICP-MS analyses did not confirm those findings. Furthermore, the topographical parameters did not significantly differ between etched cavities after caries removal using burs or Carisolv. The chemical and topographical analyses in the present study imply that any differences between the cavities after caries excavation with burs or with Carisolv are insignificant.
THE FOURIER SERIES MODEL IN MAP ANALYSIS.
During the past several years the double Fourier Series has been applied to the analysis of contour-type maps as an alternative to the more commonly...used polynomial model. The double Fourier Series has high potential in the study of areal variations, inasmuch as a succession of trend maps based on...and it is shown that the double Fourier Series can be used to summarize the directional properties of areally-distributed data. An Appendix lists
Handbook of Fourier analysis & its applications
Marks, Robert J
2009-01-01
Fourier analysis has many scientific applications - in physics, number theory, combinatorics, signal processing, probability theory, statistics, option pricing, cryptography, acoustics, oceanography, optics and diffraction, geometry, and other areas. In signal processing and related fields, Fourier analysis is typically thought of as decomposing a signal into its component frequencies and their amplitudes. This practical, applications-based professional handbook comprehensively covers the theory and applications of Fourier Analysis, spanning topics from engineering mathematics, signal process
Alunno-Bruscia, Marianne; van der Veer, Henk W.; Kooijman, Sebastiaan A. L. M.
2009-08-01
The European Research Project AquaDEB (2007-2011, http://www.ifremer.fr/aquadeb/) is joining skills and expertise of some French and Dutch research institutes and universities to analyse the physiological flexibility of aquatic organisms and to link it to ecological and evolutionary processes within a common theoretical framework for quantitative bioenergetics [Kooijman, S.A.L.M., 2000. Dynamic energy and mass budgets in biological systems. Cambridge University Press, Cambridge]. The main scientific objectives in AquaDEB are i) to study and compare the sensitivity of aquatic species (mainly molluscs and fish) to environmental variability of natural or human origin, and ii) to evaluate the related consequences at different biological levels (individual, population, ecosystem) and temporal scales (life cycle, population dynamics, evolution). At mid-term life, the AquaDEB collaboration has already yielded interesting results by quantifying bio-energetic processes of various aquatic species (e.g. molluscs, fish, crustaceans, algae) with a single mathematical framework. It has also allowed to federate scientists with different backgrounds, e.g. mathematics, microbiology, ecology, chemistry, and working in different fields, e.g. aquaculture, fisheries, ecology, agronomy, ecotoxicology, climate change. For the two coming years, the focus of the AquaDEB collaboration will be in priority: (i) to compare energetic and physiological strategies among species through the DEB parameter values and to identify the factors responsible for any differences in bioenergetics and physiology; and to compare dynamic (DEB) versus static (SEB) energy models to study the physiological performance of aquatic species; (ii) to consider different scenarios of environmental disruption (excess of nutrients, diffuse or massive pollution, exploitation by man, climate change) to forecast effects on growth, reproduction and survival of key species; (iii) to scale up the models for a few species from
COMPARISON OF FOURIER AND WAVELET TRANSFORMS IN GEOPHYSICAL APPLICATIONS
Directory of Open Access Journals (Sweden)
Hakan ALP
2008-01-01
Full Text Available In this study, it was compared Fourier Transformation using widely in analysing of geophysics data and image processing and Wavelet Transformation using in image processing, boundary analysis and recently years in use geophysical data analysis. It was applicated and compared two transformations in the both geophysical data and fundamental functions. Then the results obtained were evaluated. In this study it was compared two transformation using earthquake records and Bouger gravity anomalies map of Hatay region geophysical data. At the end of the our study it was clearly seen that wavelet transform can be used by geophysical data analysing.
2015-01-05
Semiquantitative elemental composition. – Elemental mapping and line scans. • Fourier Transform Infrared ( FTIR ) spectroscopy – Identification of chemical...Transform Infrared ( FTIR ) spectroscopy – Nicolet 6700 spectrometer. – Harrick Scientific “praying mantis” diffuse reflectance accessory. • Qualitative...VIS-NIR Spectroscopy Dianna Alaan © The Aerospace Corporation 2015 DebriSat Laboratory Analyses 5 January, 2015 Paul M. Adams1, Zachary Lingley2
Schröter, Grit; Mann, Daniel; Kötting, Carsten; Gerwert, Klaus
2015-07-10
Gα subunits are central molecular switches in cells. They are activated by G protein-coupled receptors that exchange GDP for GTP, similar to small GTPase activation mechanisms. Gα subunits are turned off by GTP hydrolysis. For the first time we employed time-resolved FTIR difference spectroscopy to investigate the molecular reaction mechanisms of Gαi1. FTIR spectroscopy is a powerful tool that monitors reactions label free with high spatio-temporal resolution. In contrast to common multiple turnover assays, FTIR spectroscopy depicts the single turnover GTPase reaction without nucleotide exchange/Mg(2+) binding bias. Global fit analysis resulted in one apparent rate constant of 0.02 s(-1) at 15 °C. Isotopic labeling was applied to assign the individual phosphate vibrations for α-, β-, and γ-GTP (1243, 1224, and 1156 cm(-1), respectively), α- and β-GDP (1214 and 1134/1103 cm(-1), respectively), and free phosphate (1078/991 cm(-1)). In contrast to Ras · GAP catalysis, the bond breakage of the β-γ-phosphate but not the Pi release is rate-limiting in the GTPase reaction. Complementary common GTPase assays were used. Reversed phase HPLC provided multiple turnover rates and tryptophan fluorescence provided nucleotide exchange rates. Experiments were complemented by molecular dynamics simulations. This broad approach provided detailed insights at atomic resolution and allows now to identify key residues of Gαi1 in GTP hydrolysis and nucleotide exchange. Mutants of the intrinsic arginine finger (Gαi1-R178S) affected exclusively the hydrolysis reaction. The effect of nucleotide binding (Gαi1-D272N) and Ras-like/all-α interface coordination (Gαi1-D229N/Gαi1-D231N) on the nucleotide exchange reaction was furthermore elucidated.
Fourier analysis and synthesis tomography.
Energy Technology Data Exchange (ETDEWEB)
Wagner, Kelvin H. (University of Colorado at Boulder, Boulder, CO); Sinclair, Michael B.; Feldkuhn, Daniel (University of Colorado at Boulder, Boulder, CO)
2010-05-01
Most far-field optical imaging systems rely on a lens and spatially-resolved detection to probe distinct locations on the object. We describe and demonstrate a novel high-speed wide-field approach to imaging that instead measures the complex spatial Fourier transform of the object by detecting its spatially-integrated response to dynamic acousto-optically synthesized structured illumination. Tomographic filtered backprojection is applied to reconstruct the object in two or three dimensions. This technique decouples depth-of-field and working-distance from resolution, in contrast to conventional imaging, and can be used to image biological and synthetic structures in fluoresced or scattered light employing coherent or broadband illumination. We discuss the electronically programmable transfer function of the optical system and its implications for imaging dynamic processes. Finally, we present for the first time two-dimensional high-resolution image reconstructions demonstrating a three-orders-of-magnitude improvement in depth-of-field over conventional lens-based microscopy.
Programs for high-speed Fourier, Mellin and Fourier-Bessel transforms
Ikhabisimov, D. K.; Debabov, A. S.; Kolosov, B. I.; Usikov, D. A.
1979-01-01
Several FORTRAN program modules for performing one-dimensional and two-dimensional discrete Fourier transforms, Mellin, and Fourier-Bessel transforms are described along with programs that realize the algebra of high speed Fourier transforms on a computer. The programs can perform numerical harmonic analysis of functions, synthesize complex optical filters on a computer, and model holographic image processing methods.
On the Fourier transform of the greatest common divisor
van der Kamp, Peter H
2012-01-01
The discrete Fourier transform of the greatest common divisor is a multiplicative function that generalises both the gcd-sum function and Euler's totient function. On the one hand it is the Dirichlet convolution of the identity with Ramanujan's sum, and on the other hand it can be written as a generalised convolution product of the identity with the totient function. We show that this arithmetic function of two integers (a,m) counts the number of elements in the set of ordered pairs (i,j) such that i*j is equivalent to a modulo m. Furthermore we generalise a dozen known identities for the totient function, to identities which involve the discrete Fourier transform of the greatest common divisor, including its partial sums, and its Lambert series.
The multipliers of multiple trigonometric Fourier series
Ydyrys, Aizhan; Sarybekova, Lyazzat; Tleukhanova, Nazerke
2016-11-01
We study the multipliers of multiple Fourier series for a regular system on anisotropic Lorentz spaces. In particular, the sufficient conditions for a sequence of complex numbers {λk}k∈Zn in order to make it a multiplier of multiple trigonometric Fourier series from Lp[0; 1]n to Lq[0; 1]n , p > q. These conditions include conditions Lizorkin theorem on multipliers.
1-Convergence of Complex Double Fourier Series
Indian Academy of Sciences (India)
Kulwinder Kaur; S S Bhatia; Babu Ram
2003-11-01
It is proved that the complex double Fourier series of an integrable function (, ) with coefficients {} satisfying certain conditions, will converge in 1-norm. The conditions used here are the combinations of Tauberian condition of Hardy–Karamata kind and its limiting case. This paper extends the result of Bray [1] to complex double Fourier series.
Two modified discrete chirp Fourier transform schemes
Institute of Scientific and Technical Information of China (English)
樊平毅; 夏香根
2001-01-01
This paper presents two modified discrete chirp Fourier transform (MDCFT) schemes.Some matched filter properties such as the optimal selection of the transform length, and its relationship to analog chirp-Fourier transform are studied. Compared to the DCFT proposed previously, theoretical and simulation results have shown that the two MDCFTs can further improve the chirp rate resolution of the detected signals.
Fractional Fourier processing of quantum light.
Sun, Yifan; Tao, Ran; Zhang, Xiangdong
2014-01-13
We have extended Fourier transform of quantum light to a fractional Fourier processing, and demonstrated that a classical optical fractional Fourier processor can be used for the shaping of quantum correlations between two or more photons. Comparing the present method with that of Fourier processing, we find that fractional Fourier processing for quantum light possesses many advantages. Based on such a method, not only quantum correlations can be shaped more rich, but also the initial states can be easily identified. Moreover, the twisted phase information can be recovered and quantum states are easily controlled in performing quantum information experiments. Our findings open up new avenues for the manipulation of correlations between photons in optical quantum information processing.
Homology of balanced complexes via the Fourier transform
Meshulam, Roy
2011-01-01
Let G_0,...,G_k be finite abelian groups and let G_0*...*G_k be the join of the 0-dimensional complexes G_i. We give a characterization of the integral k-coboundaries of subcomplexes of G_0*...*G_k in terms of the Fourier transform on the group G_0 \\times ... \\times G_k. This leads to an extension of a recent result of Musiker and Reiner on a topological interpretation of the cyclotomic polynomial.
Energy Technology Data Exchange (ETDEWEB)
Zheng, Y. [Pennsylvania State Univ., University Park, PA (United States)]|[Lawrence Berkeley Lab., CA (United States); Shirley, D.A. [Pennsylvania State Univ., University Park, PA (United States)
1995-02-01
The authors show by Fourier analyses of experimental data, with no further treatment, that the positions of all the strong peaks in Fourier transforms of angle-resolved photoemission extended fine structure (ARPEFS) from adsorbed surfaces can be explicitly predicted from a trial structure with an accuracy of about {+-} 0.3 {angstrom} based on a single-scattering cluster model together with the concept of a strong backscattering cone, and without any additional analysis. This characteristic of ARPEFS Fourier transforms can be developed as a simple method for determining the structures of adsorbed surfaces to an accuracy of about {+-} 0.1 {angstrom}.
Lo, Men-Tzung; Novak, Vera; Peng, C-K; Liu, Yanhui; Hu, Kun
2009-06-01
Phase interactions among signals of physical and physiological systems can provide useful information about the underlying control mechanisms of the systems. Physical and biological recordings are often noisy and exhibit nonstationarities that can affect the estimation of phase interactions. We systematically studied effects of nonstationarities on two phase analyses including (i) the widely used transfer function analysis (TFA) that is based on Fourier decomposition and (ii) the recently proposed multimodal pressure flow (MMPF) analysis that is based on Hilbert-Huang transform (HHT)-an advanced nonlinear decomposition algorithm. We considered three types of nonstationarities that are often presented in physical and physiological signals: (i) missing segments of data, (ii) linear and step-function trends embedded in data, and (iii) multiple chaotic oscillatory components at different frequencies in data. By generating two coupled oscillatory signals with an assigned phase shift, we quantify the change in the estimated phase shift after imposing artificial nonstationarities into the oscillatory signals. We found that all three types of nonstationarities affect the performances of the Fourier-based and the HHT-based phase analyses, introducing bias and random errors in the estimation of the phase shift between two oscillatory signals. We also provided examples of nonstationarities in real physiological data (cerebral blood flow and blood pressure) and showed how nonstationarities can complicate result interpretation. Furthermore, we propose certain strategies that can be implemented in the TFA and the MMPF methods to reduce the effects of nonstationarities, thus improving the performances of the two methods.
Mergner, H.; Schuhmacher, H.
1985-12-01
The Sanganeb-Atoll off Port Sudan is an elongate annular reef which rests on a probably raised block in the fracture zone along the Red Sea-graben. Its gross morphology was most likely formed by subaerial erosion during low sealevel conditions. Features of its topography and hydrography are described. The prevailing wind waves are from NE, Hence, the outer and inner reef slopes are exposed to different hydrodynamic conditions. The sessile benthos was analysed using the quadrat method. Four test quadrats (5×5 m each) were selected on the outer and inner slopes at a depth of 10 m along a SSW-NNE transect across the atoll. Cnidaria were by far the most dominating group; coralline algae, Porifera, Bryozoa and Ascidia, however, counted for just under 3 % living cover. Light and temperature intensities did not differ significantly at the sites studied; water movement, however, decreased in the following order: TQ IV (outer NE side of the reef ring) was exposed to strong swell and surf; TQ II (inner side of the SW-ring) was met by a strong longreef current; TQ I was situated on the outer lee of the SW-atoll ring and TQ III in the inner lee of the NE-side. This hydrodynamic gradient correlates with the composition of the coral communities from predominantly branching Scleractinia (staghorn-like and other Acropora species and Pocillopora) in TQ IV, through a Lobophyllia, Porites and Xenia-dominated community in TQ II, and a mixed community with an increasing percentage of xeniid and alcyoniid soft corals in TQ I, to a community in TQ III which is dominated by the soft corals Sinularia and Dendronephthya. The cnidarian cover ranged between 42.4 and 56.6 % whereby the two exposed test quadrats had a higher living coverage than the protected ones. In total, 2649 colonies comprising 124 species of stony, soft and hydrocorals were recorded by an elaborate method of accurate in-situ mapping. The 90 scleractinian species found include 3 species new to the Red Sea and 11 hitherto
The Geostationary Fourier Transform Spectrometer
Key, Richard; Sander, Stanley; Eldering, Annmarie; Blavier, Jean-Francois; Bekker, Dmitriy; Manatt, Ken; Rider, David; Wu, Yen-Hung
2012-01-01
The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for a geostationary orbit (GEO) earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. GEO allows GeoFTS to continuously stare at a region of the earth for frequent sampling to capture the variability of biogenic fluxes and anthropogenic emissions from city to continental spatial scales and temporal scales from diurnal, synoptic, seasonal to interannual. The measurement strategy provides a process based understanding of the carbon cycle from contiguous maps of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) collected many times per day at high spatial resolution (2.7kmx2.7km at nadir). The CO2/CH4/CO/CF measurement suite in the near infrared spectral region provides the information needed to disentangle natural and anthropogenic contributions to atmospheric carbon concentrations and to minimize uncertainties in the flow of carbon between the atmosphere and surface. The half meter cube size GeoFTS instrument is based on a Michelson interferometer design that uses all high TRL components in a modular configuration to reduce complexity and cost. It is self-contained and as independent of the spacecraft as possible with simple spacecraft interfaces, making it ideal to be a "hosted" payload on a commercial communications satellite mission. The hosted payload approach for measuring the major carbon-containing gases in the atmosphere from the geostationary vantage point will affordably advance the scientific understating of carbon cycle processes and climate change.
Kline, Neal; Huang, Meng; Miller, Terry A.
2016-06-01
Cavity ringdown, near-infrared spectra have been previously observed following the photolysis of the dihalomethanes(CH{_2}XI, X = I, Br, Cl) in the presence of O{_2} and N{_2}. In last year's Symposium, we presented evidence that all the spectra could be attributed to the tilde{A}-tilde{X} electronic transition of the appropriate CH{_2}XOO{\\cdot} radical. We now present detailed analyses of these spectra. Similar spectral features have been observed for all radicals. The first strong transitions are located around 6800 cm{-1}, and are assigned as associated with the origin. Other strong transitions are observed about 800 cm{-1} blue of the origin, and have a multiple-peak structure similar to the corresponding origin bands. These bands are assigned to be the OO stretch of the tilde{A}-tilde{X} electronic transitions, which are typically strong in the spectra of peroxy radicals, based on electronic structure calculations that provide vibrational frequencies and Franck-Condon factors. One-dimensional calculations of the internal torsion mode are applied to specifically explain the multiple-peak features in both the origin and OO stretch region as series of transitions including sequence bands and other hot bands from the vibrationally excited states of the low-frequency torsion mode in the tilde{X} state, which are significantly populated at room temperature. Additional bands can be assigned to fundamentals or combination bands of various other tilde{A} state modes. N. D. Kline, M. Huang, T. A. Miller, P. Lolur, R. Dawes, FD05, 70th International Symposium of Molecular Spectroscopy(2015)
Fourier transforms in radar and signal processing
Brandwood, David
2011-01-01
Fourier transforms are used widely, and are of particular value in the analysis of single functions and combinations of functions found in radar and signal processing. Still, many problems that could have been tackled by using Fourier transforms may have gone unsolved because they require integration that is difficult and tedious. This newly revised and expanded edition of a classic Artech House book provides you with an up-to-date, coordinated system for performing Fourier transforms on a wide variety of functions. Along numerous updates throughout the book, the Second Edition includes a crit
Harmonic functions on groups and Fourier algebras
Chu, Cho-Ho
2002-01-01
This research monograph introduces some new aspects to the theory of harmonic functions and related topics. The authors study the analytic algebraic structures of the space of bounded harmonic functions on locally compact groups and its non-commutative analogue, the space of harmonic functionals on Fourier algebras. Both spaces are shown to be the range of a contractive projection on a von Neumann algebra and therefore admit Jordan algebraic structures. This provides a natural setting to apply recent results from non-associative analysis, semigroups and Fourier algebras. Topics discussed include Poisson representations, Poisson spaces, quotients of Fourier algebras and the Murray-von Neumann classification of harmonic functionals.
From fractional Fourier transformation to quantum mechanical fractional squeezing transformation
Institute of Scientific and Technical Information of China (English)
吕翠红; 范洪义; 李东韡
2015-01-01
By converting the triangular functions in the integration kernel of the fractional Fourier transformation to the hy-perbolic function, i.e., tanα→tanhα, sinα→sinhα, we find quantum mechanical fractional squeezing transformation (FrST) which satisfies additivity. By virtue of the integration technique within ordered product of operators (IWOP) wederive the unitary operator responsible for the FrST, which is composite and is made of eiπa†a/2 and exp[ iα2 (a2+a†2)]. The FrST may be implemented in combinations of quadratic nonlinear crystals with different phase mismatches.
Fourier Series for Kample De Feriet Function
Directory of Open Access Journals (Sweden)
A. D. Wadhwa
1971-07-01
Full Text Available Some integrals involving Kampe de Feriet function have been evaluated. These integrals have further been employed to obtain some Fourier series for Kampe de Feriet functions. Some particular cases have also been discussed.
Fourier-Bessel rotational invariant eigenimages.
Zhao, Zhizhen; Singer, Amit
2013-05-01
We present an efficient and accurate algorithm for principal component analysis (PCA) of a large set of two-dimensional images and, for each image, the set of its uniform rotations in the plane and its reflection. The algorithm starts by expanding each image, originally given on a Cartesian grid, in the Fourier-Bessel basis for the disk. Because the images are essentially band limited in the Fourier domain, we use a sampling criterion to truncate the Fourier-Bessel expansion such that the maximum amount of information is preserved without the effect of aliasing. The constructed covariance matrix is invariant to rotation and reflection and has a special block diagonal structure. PCA is efficiently done for each block separately. This Fourier-Bessel-based PCA detects more meaningful eigenimages and has improved denoising capability compared to traditional PCA for a finite number of noisy images.
Composite Cyclotomic Fourier Transforms with Reduced Complexities
Wu, Xuebin; Chen, Ning; Yan, Zhiyuan; Wang, Ying
2010-01-01
Discrete Fourier transforms~(DFTs) over finite fields have widespread applications in digital communication and storage systems. Hence, reducing the computational complexities of DFTs is of great significance. Recently proposed cyclotomic fast Fourier transforms (CFFTs) are promising due to their low multiplicative complexities. Unfortunately, there are two issues with CFFTs: (1) they rely on efficient short cyclic convolution algorithms, which has not been investigated thoroughly yet, and (2) they have very high additive complexities when directly implemented. In this paper, we address both issues. One of the main contributions of this paper is efficient bilinear 11-point cyclic convolution algorithms, which allow us to construct CFFTs over GF$(2^{11})$. The other main contribution of this paper is that we propose composite cyclotomic Fourier transforms (CCFTs). In comparison to previously proposed fast Fourier transforms, our CCFTs achieve lower overall complexities for moderate to long lengths, and the imp...
Electronically-Scanned Fourier-Transform Spectrometer
Breckinridge, J. B.; Ocallaghan, F. G.
1984-01-01
Instrument efficient, lightweight, and stable. Fourier-transform spectrometer configuration uses electronic, instead of mechanical, scanning. Configuration insensitive to vibration-induced sampling errors introduced into mechanically scanned systems.
Wavelet-Fourier self-deconvolution
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Using a wavelet function as the filter function of Fourier self-deconvolution, a new me- thod of resolving overlapped peaks, wavelet-Fourier self-deconvolution, is founded. The properties of different wavelet deconvolution functions are studied. In addition, a cutoff value coefficient method of eliminating artificial peaks and wavelet method of removing shoulder peaks using the ratio of maximum peak to minimum peak is established. As a result, some problems in classical Fourier self-deconvolution are solved, such as the bad result of denoising, complicated processing, as well as usual appearance of artificial and shoulder peaks. Wavelet-Fourier self-deconvolution is applied to determination of multi-components in oscillographic chronopotentiometry. Experimental results show that the method has characteristics of simpler process and better effect of processing.
Wavelet-Fourier self-deconvolution
Institute of Scientific and Technical Information of China (English)
郑建斌; 张红权; 高鸿
2000-01-01
Using a wavelet function as the filter function of Fourier self-deconvolution, a new method of resolving overlapped peaks, wavelet-Fourier self-deconvolution, is founded. The properties of different wavelet deconvolution functions are studied. In addition, a cutoff value coefficient method of eliminating artificial peaks and wavelet method of removing shoulder peaks using the ratio of maximum peak to minimum peak is established. As a result, some problems in classical Fourier self-deconvolution are solved, such as the bad result of denoising, complicated processing, as well as usual appearance of artificial and shoulder peaks. Wavelet-Fourier self-deconvolution is applied to determination of multi-components in oscillographic chronopotentiometry. Experimental results show that the method has characteristics of simpler process and better effect of processing.
Content adaptive illumination for Fourier ptychography.
Bian, Liheng; Suo, Jinli; Situ, Guohai; Zheng, Guoan; Chen, Feng; Dai, Qionghai
2014-12-01
Fourier ptychography (FP) is a recently reported technique, for large field-of-view and high-resolution imaging. Specifically, FP captures a set of low-resolution images, under angularly varying illuminations, and stitches them together in the Fourier domain. One of FP's main disadvantages is its long capturing process, due to the requisite large number of incident illumination angles. In this Letter, utilizing the sparsity of natural images in the Fourier domain, we propose a highly efficient method, termed adaptive Fourier ptychography (AFP), which applies content adaptive illumination for FP, to capture the most informative parts of the scene's spatial spectrum. We validate the effectiveness and efficiency of the reported framework, with both simulated and real experiments. Results show that the proposed AFP could shorten the acquisition time of conventional FP, by around 30%-60%.
A new twist to fourier transforms
Meikle, Hamish D
2004-01-01
Making use of the inherent helix in the Fourier transform expression, this book illustrates both Fourier transforms and their properties in the round. The author draws on elementary complex algebra to manipulate the transforms, presenting the ideas in such a way as to avoid pages of complicated mathematics. Similarly, abbreviations are not used throughout and the language is kept deliberately clear so that the result is a text that is accessible to a much wider readership.The treatment is extended with the use of sampled data to finite and discrete transforms, the fast Fourier transform, or FFT, being a special case of a discrete transform. The application of Fourier transforms in statistics is illustrated for the first time using the examples operational research and later radar detection. In addition, a whole chapter on tapering or weighting functions is added for reference. The whole is rounded off by a glossary and examples of diagrams in three dimensions made possible by today's mathematics programs
Implementing quantum Fourier transform with integrated photonic devices
Tabia, Gelo Noel
2014-03-01
Many quantum algorithms that exhibit exponential speedup over their classical counterparts employ the quantum Fourier transform, which is used to solve interesting problems such as prime factorization. Meanwhile, nonclassical interference of single photons achieved on integrated platforms holds the promise of achieving large-scale quantum computation with multiport devices. An optical multiport device can be built to realize any quantum circuit as a sequence of unitary operations performed by beam splitters and phase shifters on path-encoded qudits. In this talk, I will present a recursive scheme for implementing quantum Fourier transform with a multimode interference photonic integrated circuit. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Research and Innovation.
Fourier-positivity constraints on QCD dipole models
Directory of Open Access Journals (Sweden)
Bertrand G. Giraud
2016-09-01
Full Text Available Fourier-positivity (F-positivity, i.e. the mathematical property that a function has a positive Fourier transform, can be used as a constraint on the parametrization of QCD dipole-target cross-sections or Wilson line correlators in transverse position space r. They are Bessel transforms of positive transverse momentum dependent gluon distributions. Using mathematical F-positivity constraints on the limit r→0 behavior of the dipole amplitudes, we identify the common origin of the violation of F-positivity for various, however phenomenologically convenient, dipole models. It is due to the behavior r2+ϵ, ϵ>0 softer, even slightly, than color transparency. F-positivity seems thus to conflict with the present dipole formalism when it includes a QCD running coupling constant α(r.
A DISTRIBUTION SPACE FOR FOURIER TRANSFORM
Institute of Scientific and Technical Information of China (English)
Zhou Chaoying; Yang Lihua; Huang Daren
2007-01-01
A space DF is constructed and some characterizations of space DF are given. Itis shown that the classical Fourier transform is extended to the distribution space D'F, whichcan be embedded into the Schwartz distribution space D' continuously. It is also shown thatD'F is the biggest embedded subspace of D' on which the extended Fourier transform, F, is ahomeomorphism of D'F onto itself.
Shift sampling theory of Fourier transform computation
Institute of Scientific and Technical Information of China (English)
柴玉璞
1997-01-01
The DFT transform us extended to DFTξη transform and the relationship between FT and DFTξη is given by the Fourier transform discretization theorem. Based on the theorem, the DFTξη algorithm-error equation (DFTξη A-E equation) is established, and the minimization property of discrete effect and the oscillation property of truncation effect are demonstrated. All these construct the shift sampling theory——a new theory about Fourier transform computation.
Fractional Fourier transform of Lorentz beams
Institute of Scientific and Technical Information of China (English)
Zhou Guo-Quan
2009-01-01
This paper introduces Lorentz beams to describe certain laser sources that produce highly divergent fields. The fractional Fourier transform (FRFT) is applied to treat the propagation of Lorentz beams. Based on the definition of convolution and the convolution theorem of the Fourier transform, an analytical expression for a Lorentz beam passing through a FRFT system has been derived. By using the derived formula, the properties of a Lorentz beam in the FRFT plane are illustrated numerically.
The Non-uniform Fast Fourier Transform in Computed Tomography
Tang, Junqi
2016-01-01
This project is aimed at designing the fast forward projection algorithm and also the backprojection algorithm for cone beam CT imaging systems with circular X-ray source trajectory. The principle of the designs is based on utilizing the potential computational efficiency which the Fourier Slice Theorem and the Non-uniform Fast Fourier Transform (NUFFT) will bring forth. In this Masters report, the detailed design of the NUFFT based forward projector including a novel 3D (derivative of) Radon space resampling method will be given. Meanwhile the complexity of the NUFFT based forward projector is analysed and compared with the non-Fourier based CT projector, and the advantage of the NUFFT based forward projection in terms of the computational efficiency is demonstrated in this report. Base on the design of the forward algorithm, the NUFFT based 3D direct reconstruction algorithm will be derived. The experiments will be taken to test the performance of the forward algorithm and the backprojection algorithm to sh...
Elliptical Fourier analysis: fundamentals, applications, and value for forensic anthropology.
Caple, Jodi; Byrd, John; Stephan, Carl N
2017-02-17
The numerical description of skeletal morphology enables forensic anthropologists to conduct objective, reproducible, and structured tests, with the added capability of verifying morphoscopic-based analyses. One technique that permits comprehensive quantification of outline shape is elliptical Fourier analysis. This curve fitting technique allows a form's outline to be approximated via the sum of multiple sine and cosine waves, permitting the profile perimeter of an object to be described in a dense (continuous) manner at a user-defined level of precision. A large amount of shape information (the entire perimeter) can thereby be collected in contrast to other methods relying on sparsely located landmarks where information falling in between the landmarks fails to be acquired. First published in 1982, elliptical Fourier analysis employment in forensic anthropology from 2000 onwards reflects a slow uptake despite large computing power that makes its calculations easy to conduct. Without hurdles arising from calculation speed or quantity, the slow uptake may partly reside with the underlying mathematics that on first glance is extensive and potentially intimidating. In this paper, we aim to bridge this gap by pictorially illustrating how elliptical Fourier harmonics work in a simple step-by-step visual fashion to facilitate universal understanding and as geared towards increased use in forensic anthropology. We additionally provide a short review of the method's utility for osteology, a summary of past uses in forensic anthropology, and software options for calculations that largely save the user the trouble of coding customized routines.
Breitbart, M.; Hollander, D.; Nitti, A.; van Mooy, B.; Siefert, J.; Souza, V.
2010-04-01
This study utilized metagenomic and stable isotopic analyses to examine the microorganisms and chemical processes leading to carbonate precipitation in the actively-accreting freshwater microbialites from Rio Mesquites in Cuatro Ciénegas, Mexico.
Bead-Fourier path integral molecular dynamics
Ivanov, Sergei D.; Lyubartsev, Alexander P.; Laaksonen, Aatto
2003-06-01
Molecular dynamics formulation of Bead-Fourier path integral method for simulation of quantum systems at finite temperatures is presented. Within this scheme, both the bead coordinates and Fourier coefficients, defining the path representing the quantum particle, are treated as generalized coordinates with corresponding generalized momenta and masses. Introduction of the Fourier harmonics together with the center-of-mass thermostating scheme is shown to remove the ergodicity problem, known to pose serious difficulties in standard path integral molecular dynamics simulations. The method is tested for quantum harmonic oscillator and hydrogen atom (Coulombic potential). The simulation results are compared with the exact analytical solutions available for both these systems. Convergence of the results with respect to the number of beads and Fourier harmonics is analyzed. It was shown that addition of a few Fourier harmonics already improves the simulation results substantially, even for a relatively small number of beads. The proposed Bead-Fourier path integral molecular dynamics is a reliable and efficient alternative to simulations of quantum systems.
Fourier Transform Near Infrared Spectrometry: Using Interferograms To Determine Chemical Composition
Hoy, R. M.; McClure, W. Fred
1989-12-01
Previous research conducted in this laboratory has demonstrated several advantages accrued by transforming near infrared spectra from the wavelength domain to the Fourier domain. Those advantages include: [1] smoothing wavelength domain data without loss of end points, [2] correcting for particle size phenomena encountered in solid sample analyses by simply omitting the mean term Fourier coefficient from the "retransformation process", [3] minimizing the multicollinearity problem prevalent in wavelength space, [4] generating wavelength-space derivatives from Fourier space without loss of end points, [5] performing band enhancements via Fourier self-deconvolution, [6] identifying sample type using Fourier vectors, [7] estimating chemical composition using only the first few Fourier coefficients, [8] cutting of computer storage requirements by more than 96%, [9] cutting of calibration time by more than 96%, hence [10] reducing the drudgery of maintaining calibrations. That the first 12 Fourier coefficients contain sufficient information to determine chemical constituents in many products has turned out to be a major advantage leading us to understand that the chemical absorption information in the wavelength spectrum of a sample obtained with an interferometer was also present in the interferogram.
Sawyer, Nicola; Blennerhassett, John; Lambert, Ramon; Sheehan, Paul; Vasikaran, Samuel D
2014-07-01
False-positive cardiac troponin (Tn) results caused by outliers have been reported on various analytical platforms. We have compared the precision profile and outlier rate of the Abbott Diagnostics contemporary troponin I (TnI) assay with their high sensitivity (hs) TnI assay. Three studies were conducted over a 10-month period using routine patients' samples. TnI was measured in duplicate using the contemporary TnI assay in Study 1 and Study 2 (n = 7011 and 7089) and the hs-TnI assay in Study 3 (n = 1522). Critical outliers were defined as duplicate results whose absolute difference exceeded a critical difference (CD = z x √2 x SDAnalytical) at a probability level of 0.0005, with one of the results on the opposite side of the decision limit to its partner. The TnI concentration at 10% imprecision (coefficient of variation) for the contemporary TnI assay was 0.034 µg/L (Study 1) and 0.042 µg/L (Study 2), and 0.006 µg/L (6 ng/L) for the hs-TnI assay. The critical outlier rates for the contemporary TnI assay were 0.51% (Study 1) and 0.37% (Study 2) using a cut-off of 0.04 µg/L, and 0% for the hs-TnI assay using gender-specific cut-offs. The significant number of critical outliers detected using the contemporary TnI assay may pose a risk for misclassification of patients. By contrast, no critical outliers were detected using the hs-TnI assay. However, the total outlier rates for both assays were significantly higher than the expected variability of either assay. The cause of these outliers remains unclear. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
Antczak, K; Wilczyńska, U
1980-01-01
2 statistical models for evaluation of toxicological studies results have been presented. Model I. after R. Hoschek and H. J. Schittke (2) involves: 1. Elimination of the values deviating from most results-by Grubbs' method (2). 2. Analysis of the differences between the results obtained by the participants of the action and tentatively assumed value. 3. Evaluation of significant differences between the reference value and average value for a given series of measurements. 4. Thorough evaluation of laboratories based on evaluation coefficient fx. Model II after Keppler et al. As a criterion for evaluating the results the authors assumed the median. Individual evaluation of laboratories was performed on the basis of: 1. Adjusted test "t" 2. Linear regression test.
Generalized Fourier-grid R-matrix theory: a discrete Fourier-Riccati-Bessel transform approach
Energy Technology Data Exchange (ETDEWEB)
Layton, E.G. (Joint Inst. for Lab. Astrophysics, Boulder, CO (United States)); Stade, E. (Colorado Univ., Boulder, CO (United States). Dept. of Mathematics)
1993-08-28
We present the latest developments in the Fourier-grid R-matrix theory of scattering. These developments are based on the generalized Fourier-grid formalism and use a new type of extended discrete Fourier transform: the discrete Fourier-Riccati-Bessel transform. We apply this new R-matrix approach to problems of potential scattering, to demonstrate how this method reduces computational effort by incorporating centrifugal effects into the representation. As this technique is quite new, we have hopes to broaden the formalism to many types of problems. (author).
Directory of Open Access Journals (Sweden)
Arash Hanifi
Full Text Available Hyaline cartilage and mechanically inferior fibrocartilage consisting of mixed collagen types are frequently found together in repairing articular cartilage. The present study seeks to develop methodology to identify collagen type and other tissue components using Fourier transform infrared (FTIR spectral evaluation of matrix composition in combination with multivariate analyses. FTIR spectra of the primary molecular components of repair cartilage, types I and II collagen, and aggrecan, were used to develop multivariate spectral models for discrimination of the matrix components of the tissues of interest. Infrared imaging data were collected from bovine bone, tendon, normal cartilage, meniscus and human repair cartilage tissues, and composition predicted using partial least squares analyses. Histology and immunohistochemistry results were used as standards for validation. Infrared fiber optic probe spectral data were also obtained from meniscus (a tissue with mixed collagen types to evaluate the potential of this method for identification of collagen type in a minimally-invasive clinical application. Concentration profiles of the tissue components obtained from multivariate analysis were in excellent agreement with histology and immunohistochemistry results. Bone and tendon showed a uniform distribution of predominantly type I collagen through the tissue. Normal cartilage showed a distribution of type II collagen and proteoglycan similar to the known composition, while in repair cartilage, the spectral distribution of both types I and II collagen were similar to that observed via immunohistochemistry. Using the probe, the outer and inner regions of the meniscus were shown to be primarily composed of type I and II collagen, respectively, in accordance with immunohistochemistry data. In summary, multivariate analysis of infrared spectra can indeed be used to differentiate collagen type I and type II, even in the presence of proteoglycan, in
DEFF Research Database (Denmark)
Hjalager, Anne-Mette
1999-01-01
Undersøgelsen omfatter alle restaurantvirksomheder i Danmark i perioden 1980-1994. Den kortlægger livsforløb, og undersøger sammenhænge med geografi, størrelse, ejerforhold, medarbejdersammensætning m.v. Ikke overraskende findes, at restaurantsektoren er en meget turbulent branche med en stor uds...
DEFF Research Database (Denmark)
Hjalager, Anne-Mette
1999-01-01
Undersøgelsen omfatter alle restaurantvirksomheder i Danmark i perioden 1980-1994. Den kortlægger livsforløb, og undersøger sammenhænge med geografi, størrelse, ejerforhold, medarbejdersammensætning m.v. Ikke overraskende findes, at restaurantsektoren er en meget turbulent branche med en stor uds...
Modeling the reconstructed BAO in Fourier space
Seo, Hee-Jong; Beutler, Florian; Ross, Ashley J.; Saito, Shun
2016-08-01
The density field reconstruction technique, which partially reverses the non-linear degradation of the Baryon acoustic oscillation (BAO) feature in the galaxy redshift surveys, has been successful in substantially improving the cosmology constraints from recent surveys such as Baryon Oscillation Spectroscopic Survey (BOSS). We estimate the efficiency of the method as a function of various reconstruction details. To directly quantify the BAO information in non-linear density fields before and after reconstruction, we calculate the cross-correlations (i.e. propagators) of the pre(post)-reconstructed density field with the initial linear field using a mock sample that mimics the clustering of the BOSS galaxies. The results directly provide the BAO damping as a function of wavenumber that can be implemented into the Fisher matrix analysis. We focus on investigating the dependence of the propagator on a choice of smoothing filters and on two major different conventions of the redshift-space density field reconstruction that have been used in literature. By estimating the BAO signal to noise for each case, we predict constraints on the angular diameter distance and Hubble parameter using the Fisher matrix analysis. We thus determine an optimal Gaussian smoothing filter scale for the signal-to-noise level of the BOSS CMASS. We also present appropriate BAO fitting models for different reconstruction methods based on the first- and second-order Lagrangian perturbation theory in Fourier space. Using the mock data, we show that the modified BAO fitting model can substantially improve the accuracy of the BAO position in the best fits as well as the goodness of the fits.
DEFF Research Database (Denmark)
Goth Olesen, Mai; Blikra Vea, Eldbjørg; Lindgaard-Jørgensen, Palle;
2014-01-01
Danske forsyninger står overfor nye muligheder for at implementere alternative teknologier i byernes vandforsyning. Målet er, at reducere miljøeffekterne af vandforsyningen, samtidig med at omkostninger reduceres. Eco-efficiency analyse er et værktøj, der beregner miljøeffekterne og relaterer dem...
Evaluation of gastric motility by Fourier analysis of condensed images
Energy Technology Data Exchange (ETDEWEB)
Linke, R.; Muenzing, W.; Hahn, K.; Tatsch, K. [Dept. of Nuclear Medicine, Univ. of Munich, Munich (Germany)
2000-10-01
In this study Fourier analysis was applied to condensed images of gastric emptying with the aim of evaluating the amplitude and frequency of gastric contractions as well as gastric emptying in patients with various well-defined disorders. In 15 controls, 65 patients with progressive systemic sclerosis (PSS), 41 patients with diabetes mellitus type I (DM), 12 patients with pyloric stenosis and 9 patients who had undergone gastric surgery, gastric emptying was determined after ingestion of a semi-solid test meal. In addition, condensed images were generated to evaluate the amplitude and frequency of gastric contractions by means of Fourier analysis. In PSS and DM patients, gastric emptying and contraction amplitudes were significantly reduced (P<0.01). Patients with pyloric stenosis displayed regular peristalsis but significantly delayed emptying (P<0.01). Patients who had undergone gastric surgery showed normal or rapid gastric emptying associated with decreased amplitudes (P<0.01). The frequency of gastric contractions in the patient groups was not different from that in controls. This study showed Fourier analysis of condensed images to be a rapid and feasible approach for the evaluation of gastric contractions. Depending on the underlying disorder, gastric emptying and peristalsis showed both corresponding and discrepant findings. Data on gastric contractions provided additional information compared with results obtained by conventional emptying studies. Therefore, both parameters should be routinely assessed to further improve characterisation of gastric dysfunction by scintigraphy. (orig.)
Shirayama, Masaki; Kadowaki, Hideyuki; Miyadera, Tetsuhiko; Sugita, Takeshi; Tamakoshi, Masato; Kato, Masato; Fujiseki, Takemasa; Murata, Daisuke; Hara, Shota; Murakami, Takurou N.; Fujimoto, Shohei; Chikamatsu, Masayuki; FUJIWARA, HIROYUKI
2015-01-01
We report artifact-free CH3NH3PbI3 optical constants extracted from ultra-smooth perovskite layers without air exposure and assign all the optical transitions in the visible/ultraviolet region unambiguously based on density functional theory (DFT) analysis that assumes a simple pseudo-cubic crystal structure. From the self-consistent spectroscopic ellipsometry analysis of the ultra-smooth CH3NH3PbI3 layers, we find that the absorption coefficients of CH3NH3PbI3 (alpha = 3.8 x 10^4 cm-1 at 2.0...
DEFF Research Database (Denmark)
Barco, L.; Mancin, M.; Ruffa, M.
2012-01-01
in Italy, particularly as far as veterinary isolates are concerned. For this reason, a data set of 877 strains isolated in the north-east of Italy from foodstuffs, animals and environment was analysed during 2005-2010. The Random Forests (RF) method was used to identify the most important epidemiological...
Masked object registration in the Fourier domain.
Padfield, Dirk
2012-05-01
Registration is one of the most common tasks of image analysis and computer vision applications. The requirements of most registration algorithms include large capture range and fast computation so that the algorithms are robust to different scenarios and can be computed in a reasonable amount of time. For these purposes, registration in the Fourier domain using normalized cross-correlation is well suited and has been extensively studied in the literature. Another common requirement is masking, which is necessary for applications where certain regions of the image that would adversely affect the registration result should be ignored. To address these requirements, we have derived a mathematical model that describes an exact form for embedding the masking step fully into the Fourier domain so that all steps of translation registration can be computed efficiently using Fast Fourier Transforms. We provide algorithms and implementation details that demonstrate the correctness of our derivations. We also demonstrate how this masked FFT registration approach can be applied to improve the Fourier-Mellin algorithm that calculates translation, rotation, and scale in the Fourier domain. We demonstrate the computational efficiency, advantages, and correctness of our algorithm on a number of images from real-world applications. Our framework enables fast, global, parameter-free registration of images with masked regions.
Fourier-wavelet restoration in PET/CT brain studies
Energy Technology Data Exchange (ETDEWEB)
Knesaurek, Karin, E-mail: karin.knesaurek@mssm.edu [Division of Nuclear Medicine, The Mount Sinai Medical Center, One Gustave L. Levy Place, New York, NY 10029 (United States)
2012-10-11
Our goal is to improve brain PET imaging through the application of a novel, hybrid Fourier-wavelet (WFT) restoration technique. The major limitation of PET studies is a relatively poor resolution in comparison with MRI and CT imaging and there is a need for improved PET imaging. A GE DLS PET/CT 16 slice system was used to acquire the studies. In order to create restoration filters the point source study was performed. The 6-fillable spheres and 3D Hoffman brain phantom studies were acquired and used to test and optimize the restoration approach. The patient data used in the study were acquired in a 3D PET mode, using the standard clinical protocol. Here, we have implemented Fourier-wavelet regularized restoration. In the Fourier domain, the inverse of modulation transfer function was multiplied by a Butterworth low-pass filter, order n=6 and cut-off frequency f=0.35 cycles/pixel. In addition, wavelet (Daubechies, order 2) noise suppression was applied by 'hard threshold'. Hot spheres and 3D Hoffman brain studies showed that the restoration process not only improves resolution and contrast but also improves quantification in 3D PET/CT imaging. The average contrast increase was 19% and the quantification improved in the range 8-20% depending on sphere size. In the restored images, there was no significant increase in noise when compared with the original images. The clinical studies followed brain phantom findings, i.e., the restored images had better contrast and resolution properties, when compared with the original images. The results of the study demonstrate that the quality and quantification of 3D brain {sup 18}F FDG PET images can be significantly improved by Fourier-wavelet (WFT) restoration filtering.
Fourier-wavelet restoration in PET/CT brain studies
Knešaurek, Karin
2012-10-01
Our goal is to improve brain PET imaging through the application of a novel, hybrid Fourier-wavelet (WFT) restoration technique. The major limitation of PET studies is a relatively poor resolution in comparison with MRI and CT imaging and there is a need for improved PET imaging. A GE DLS PET/CT 16 slice system was used to acquire the studies. In order to create restoration filters the point source study was performed. The 6-fillable spheres and 3D Hoffman brain phantom studies were acquired and used to test and optimize the restoration approach. The patient data used in the study were acquired in a 3D PET mode, using the standard clinical protocol. Here, we have implemented Fourier-wavelet regularized restoration. In the Fourier domain, the inverse of modulation transfer function was multiplied by a Butterworth low-pass filter, order n=6 and cut-off frequency f=0.35 cycles/pixel. In addition, wavelet (Daubechies, order 2) noise suppression was applied by “hard threshold”. Hot spheres and 3D Hoffman brain studies showed that the restoration process not only improves resolution and contrast but also improves quantification in 3D PET/CT imaging. The average contrast increase was 19% and the quantification improved in the range 8-20% depending on sphere size. In the restored images, there was no significant increase in noise when compared with the original images. The clinical studies followed brain phantom findings, i.e., the restored images had better contrast and resolution properties, when compared with the original images. The results of the study demonstrate that the quality and quantification of 3D brain 18F FDG PET images can be significantly improved by Fourier-wavelet (WFT) restoration filtering.
A resource-efficient adaptive Fourier analyzer
Hajdu, C. F.; Zamantzas, C.; Dabóczi, T.
2016-10-01
We present a resource-efficient frequency adaptation method to complement the Fourier analyzer proposed by Péceli. The novel frequency adaptation scheme is based on the adaptive Fourier analyzer suggested by Nagy. The frequency adaptation method was elaborated with a view to realizing a detector connectivity check on an FPGA in a new beam loss monitoring (BLM) system, currently being developed for beam setup and machine protection of the particle accelerators at the European Organisation for Nuclear Research (CERN). The paper summarizes the Fourier analyzer to the extent relevant to this work and the basic principle of the related frequency adaptation methods. It then outlines the suggested new scheme, presents practical considerations for implementing it and underpins it with an example and the corresponding operational experience.
Practical Fourier analysis for multigrid methods
Wienands, Roman
2004-01-01
Before applying multigrid methods to a project, mathematicians, scientists, and engineers need to answer questions related to the quality of convergence, whether a development will pay out, whether multigrid will work for a particular application, and what the numerical properties are. Practical Fourier Analysis for Multigrid Methods uses a detailed and systematic description of local Fourier k-grid (k=1,2,3) analysis for general systems of partial differential equations to provide a framework that answers these questions.This volume contains software that confirms written statements about convergence and efficiency of algorithms and is easily adapted to new applications. Providing theoretical background and the linkage between theory and practice, the text and software quickly combine learning by reading and learning by doing. The book enables understanding of basic principles of multigrid and local Fourier analysis, and also describes the theory important to those who need to delve deeper into the detai...
Fourier analysis and boundary value problems
Gonzalez-Velasco, Enrique A
1996-01-01
Fourier Analysis and Boundary Value Problems provides a thorough examination of both the theory and applications of partial differential equations and the Fourier and Laplace methods for their solutions. Boundary value problems, including the heat and wave equations, are integrated throughout the book. Written from a historical perspective with extensive biographical coverage of pioneers in the field, the book emphasizes the important role played by partial differential equations in engineering and physics. In addition, the author demonstrates how efforts to deal with these problems have lead to wonderfully significant developments in mathematics.A clear and complete text with more than 500 exercises, Fourier Analysis and Boundary Value Problems is a good introduction and a valuable resource for those in the field.Key Features* Topics are covered from a historical perspective with biographical information on key contributors to the field* The text contains more than 500 exercises* Includes practical applicati...
Replica Fourier Transform: Properties and applications
Directory of Open Access Journals (Sweden)
A. Crisanti
2015-02-01
Full Text Available The Replica Fourier Transform is the generalization of the discrete Fourier Transform to quantities defined on an ultrametric tree. It finds use in conjunction of the replica method used to study thermodynamics properties of disordered systems such as spin glasses. Its definition is presented in a systematic and simple form and its use illustrated with some representative examples. In particular we give a detailed discussion of the diagonalization in the Replica Fourier Space of the Hessian matrix of the Gaussian fluctuations about the mean field saddle point of spin glass theory. The general results are finally discussed for a generic spherical spin glass model, where the Hessian can be computed analytically.
Methods of Fourier analysis and approximation theory
Tikhonov, Sergey
2016-01-01
Different facets of interplay between harmonic analysis and approximation theory are covered in this volume. The topics included are Fourier analysis, function spaces, optimization theory, partial differential equations, and their links to modern developments in the approximation theory. The articles of this collection were originated from two events. The first event took place during the 9th ISAAC Congress in Krakow, Poland, 5th-9th August 2013, at the section “Approximation Theory and Fourier Analysis”. The second event was the conference on Fourier Analysis and Approximation Theory in the Centre de Recerca Matemàtica (CRM), Barcelona, during 4th-8th November 2013, organized by the editors of this volume. All articles selected to be part of this collection were carefully reviewed.
Projective Fourier duality and Weyl quantization
Energy Technology Data Exchange (ETDEWEB)
Aldrovandi, R.; Saeger, L.A.
1996-08-01
The Weyl-Wigner correspondence prescription, which makes large use of Fourier duality, is reexamined from the point of view of Kac algebras, the most general background for non-commutative Fourier analysis allowing for that property. It is shown how the standard Kac structure has to be extended in order to accommodate the physical requirements. An Abelian and a symmetric projective Kac algebras are shown to provide, in close parallel to the standard case, a new dual framework and a well-defined notion of projective Fourier duality for the group of translations on the plane. The Weyl formula arises naturally as an irreducible component of the duality mapping between these projective algebras. (author). 29 refs.
Energy Technology Data Exchange (ETDEWEB)
Svendsen, Svend
2011-02-15
The report collates several sub-analyses about feasible developments in relation to improved energy requirements for the most important building parts, components and installations for low-energy buildings. The aim is to achieve 75% reduction of energy consumption in the future building class 2020. The findings will contribute to the plans of introducing new building component requirements to force Danish manufacturers to use innovative solutions and to force manufacturers from other countries to market the best products only. (LN)
Directory of Open Access Journals (Sweden)
Gisele Teixeira de Souza Sora
2013-06-01
Full Text Available Pickles comprising red pepper seasoned with Parmesan cheese has been developed as a new type of product developed by family cottage industries. Two formulations were prepared, or rather, with and without the preservative potassium sorbate, which underwent several physical, chemical, microbiological and sensory analyses. Physical and chemical analyses were undertaken for acidity, pH and °Brix; microbiological analyses for total heat-tolerant coliforms, Salmonella sp, molds, yeasts; sensory aspects such as physical features, aroma, flavor and texture, coupled to purchase intention among tasters were investigated. Both formulations comprised physical, chemical and microbiological parameters within standards. Sensory evaluation showed satisfactory results and research on purchase intention showed approximately 80% acceptability. Results from physical, chemical and microbiological tests showed that pickled pepper seasoned with Parmesan cheese may be prepared with citric acid as a preservative. Sensory evaluation and purchase intention indicate a real production and sale possibility of pickled peppers seasoned with Parmesan cheese by family cottage industries.
The Symmetric Group Defies Strong Fourier Sampling: Part II
Moore, Cristopher; Moore, Cristopher; Russell, Alexander
2005-01-01
Part I of this paper showed that the hidden subgroup problem over the symmetric group--including the special case relevant to Graph Isomorphism--cannot be efficiently solved by strong Fourier sampling, even if one may perform an arbitrary POVM on the coset state. In this paper, we extend these results to entangled measurements. Specifically, we show that the hidden subgroup problem on the symmetric group cannot be solved by any POVM applied to pairs of cosets states. In particular, these hidden subgroups cannot be determined by any polynomial number of one- or two-register experiments on coset states.
Adaptive optics implementation with a Fourier reconstructor.
Glazer, Oded; Ribak, Erez N; Mirkin, Leonid
2007-02-01
Adaptive optics takes its servo feedback error cue from a wavefront sensor. The common Hartmann-Shack spot grid that represents the wavefront slopes is usually analyzed by finding the spot centroids. In a novel application, we used the Fourier decomposition of a spot pattern to find deviations from grid regularity. This decomposition was performed either in the Fourier domain or in the image domain, as a demodulation of the grid of spots. We analyzed the system, built a control loop for it, and tested it thoroughly. This allowed us to close the loop on wavefront errors caused by turbulence in the optical system.
Fourier analysis in several complex variables
Ehrenpreis, Leon
2006-01-01
Suitable for advanced undergraduates and graduate students, this text develops comparison theorems to establish the fundamentals of Fourier analysis and to illustrate their applications to partial differential equations.The three-part treatment begins by establishing the quotient structure theorem or fundamental principle of Fourier analysis. Topics include the geometric structure of ideals and modules, quantitative estimates, and examples in which the theory can be applied. The second part focuses on applications to partial differential equations and covers the solution of homogeneous and inh
Quantum transport efficiency and Fourier's law.
Manzano, Daniel; Tiersch, Markus; Asadian, Ali; Briegel, Hans J
2012-12-01
We analyze the steady-state energy transfer in a chain of coupled two-level systems connecting two thermal reservoirs. Through an analytic treatment we find that the energy current is independent of the system size, hence violating Fourier's law of heat conduction. The classical diffusive behavior in Fourier's law of heat conduction can be recovered by introducing decoherence to the quantum systems constituting the chain. We relate these results to recent discussions of energy transport in biological light-harvesting systems, and discuss the role of quantum coherence and entanglement.
Quantum transport efficiency and Fourier's law
Manzano, Daniel; Asadian, Ali; Briegel, Hans J
2011-01-01
We analyze the steady-state energy transfer in a chain of coupled two-level systems connecting two thermal reservoirs. Through an analytic treatment we find that the energy current is independent of the system size, hence violating Fourier's law of heat conduction. The classical diffusive behavior in Fourier's law of heat conduction can be recovered by introducing decoherence to the quantum systems constituting the chain. Implications of these results on energy transfer in biological light harvesting systems, and the role of quantum coherences and entanglement are discussed.
Fast Fourier Transform algorithm design and tradeoffs
Kamin, Ray A., III; Adams, George B., III
1988-01-01
The Fast Fourier Transform (FFT) is a mainstay of certain numerical techniques for solving fluid dynamics problems. The Connection Machine CM-2 is the target for an investigation into the design of multidimensional Single Instruction Stream/Multiple Data (SIMD) parallel FFT algorithms for high performance. Critical algorithm design issues are discussed, necessary machine performance measurements are identified and made, and the performance of the developed FFT programs are measured. Fast Fourier Transform programs are compared to the currently best Cray-2 FFT program.
Illustrative EDOF topics in Fourier optics
George, Nicholas; Chen, Xi; Chi, Wanli
2011-10-01
In this talk we present a series of illustrative topics in Fourier Optics that are proving valuable in the design of EDOF camera systems. They are at the level of final examination problems that have been made solvable by a student or professoi having studied from one of Joseph W. Goodman's books---our tribute for his 75fr year. As time permits, four illustrative topics are l) Electromagnetic waves and Fourier optics;2) The perfect lens; 3) Connection between phase delay and radially varying focal length in an asphere and 4) tailored EDOF designs.
Electro-optic imaging Fourier transform spectrometer
Chao, Tien-Hsin (Inventor); Znod, Hanying (Inventor)
2009-01-01
An Electro-Optic Imaging Fourier Transform Spectrometer (EOIFTS) for Hyperspectral Imaging is described. The EOIFTS includes an input polarizer, an output polarizer, and a plurality of birefringent phase elements. The relative orientations of the polarizers and birefringent phase elements can be changed mechanically or via a controller, using ferroelectric liquid crystals, to substantially measure the spectral Fourier components of light propagating through the EIOFTS. When achromatic switches are used as an integral part of the birefringent phase elements, the EIOFTS becomes suitable for broadband applications, with over 1 micron infrared bandwidth.
Implementation of quantum and classical discrete fractional Fourier transforms.
Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N; Szameit, Alexander
2016-03-23
Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools.
Shirayama, Masaki; Kadowaki, Hideyuki; Miyadera, Tetsuhiko; Sugita, Takeshi; Tamakoshi, Masato; Kato, Masato; Fujiseki, Takemasa; Murata, Daisuke; Hara, Shota; Murakami, Takurou N.; Fujimoto, Shohei; Chikamatsu, Masayuki; Fujiwara, Hiroyuki
2016-01-01
Light-induced photocarrier generation is an essential process in all solar cells, including organic-inorganic hybrid (CH3NH3PbI3 ) solar cells, which exhibit a high short-circuit current density (Jsc ) of approximately 20 mA /cm2 . Although the high Jsc observed in the hybrid solar cells relies on strong electron-photon interaction, the optical transitions in the perovskite material remain unclear. Here, we report artifact-free CH3NH3PbI3 optical constants extracted from ultrasmooth perovskite layers without air exposure and assign all of the optical transitions in the visible and ultraviolet region unambiguously, based on density-functional theory (DFT) analysis that assumes a simple pseudocubic crystal structure. From the self-consistent spectroscopic ellipsometry analysis of the ultrasmooth CH3NH3PbI3 layers, we find that the absorption coefficients of CH3NH3PbI3 (α =3.8 ×104 cm-1 at 2.0 eV) are comparable to those of CuInGaSe2 and CdTe, and high α values reported in earlier studies are overestimated seriously by the extensive surface roughness of CH3NH3PbI3 layers. The polarization-dependent DFT calculations show that CH3NH3 + interacts strongly with the PbI3 - cage, modifying the CH3NH3PbI3 dielectric function in the visible region rather significantly. In particular, the transition matrix element of CH3NH3PbI3 varies, depending on the position of CH3NH3 + within the Pb—I network. When the effect of CH3NH3 + on the optical transition is eliminated in the DFT calculation, the CH3NH3PbI3 dielectric function deduced from DFT shows an excellent agreement with the experimental result. As a result, distinct optical transitions observed at E0(Eg)=1.61 eV , E1=2.53 eV , and E2=3.24 eV in CH3NH3PbI3 are attributed to the direct semiconductor-type transitions at the R , M , and X points in the pseudocubic Brillouin zone, respectively. We further perform the quantum efficiency (QE) analysis for a standard hybrid-perovskite solar cell incorporating a mesoporous TiO2
Statistical properties of Fourier-based time-lag estimates
Epitropakis, A.; Papadakis, I. E.
2016-06-01
Context. The study of X-ray time-lag spectra in active galactic nuclei (AGN) is currently an active research area, since it has the potential to illuminate the physics and geometry of the innermost region (i.e. close to the putative super-massive black hole) in these objects. To obtain reliable information from these studies, the statistical properties of time-lags estimated from data must be known as accurately as possible. Aims: We investigated the statistical properties of Fourier-based time-lag estimates (i.e. based on the cross-periodogram), using evenly sampled time series with no missing points. Our aim is to provide practical "guidelines" on estimating time-lags that are minimally biased (i.e. whose mean is close to their intrinsic value) and have known errors. Methods: Our investigation is based on both analytical work and extensive numerical simulations. The latter consisted of generating artificial time series with various signal-to-noise ratios and sampling patterns/durations similar to those offered by AGN observations with present and past X-ray satellites. We also considered a range of different model time-lag spectra commonly assumed in X-ray analyses of compact accreting systems. Results: Discrete sampling, binning and finite light curve duration cause the mean of the time-lag estimates to have a smaller magnitude than their intrinsic values. Smoothing (i.e. binning over consecutive frequencies) of the cross-periodogram can add extra bias at low frequencies. The use of light curves with low signal-to-noise ratio reduces the intrinsic coherence, and can introduce a bias to the sample coherence, time-lag estimates, and their predicted error. Conclusions: Our results have direct implications for X-ray time-lag studies in AGN, but can also be applied to similar studies in other research fields. We find that: a) time-lags should be estimated at frequencies lower than ≈ 1/2 the Nyquist frequency to minimise the effects of discrete binning of the
Fourier theory and C∗-algebras
Bédos, Erik; Conti, Roberto
2016-07-01
We discuss a number of results concerning the Fourier series of elements in reduced twisted group C∗-algebras of discrete groups, and, more generally, in reduced crossed products associated to twisted actions of discrete groups on unital C∗-algebras. A major part of the article gives a review of our previous work on this topic, but some new results are also included.
Ultrafast Fourier-transform parallel processor
Energy Technology Data Exchange (ETDEWEB)
Greenberg, W.L.
1980-04-01
A new, flexible, parallel-processing architecture is developed for a high-speed, high-precision Fourier transform processor. The processor is intended for use in 2-D signal processing including spatial filtering, matched filtering and image reconstruction from projections.
Euler Polynomials, Fourier Series and Zeta Numbers
DEFF Research Database (Denmark)
Scheufens, Ernst E
2012-01-01
Fourier series for Euler polynomials is used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent series....
Fourier Series Formalization in ACL2(r
Directory of Open Access Journals (Sweden)
Cuong K. Chau
2015-09-01
Full Text Available We formalize some basic properties of Fourier series in the logic of ACL2(r, which is a variant of ACL2 that supports reasoning about the real and complex numbers by way of non-standard analysis. More specifically, we extend a framework for formally evaluating definite integrals of real-valued, continuous functions using the Second Fundamental Theorem of Calculus. Our extended framework is also applied to functions containing free arguments. Using this framework, we are able to prove the orthogonality relationships between trigonometric functions, which are the essential properties in Fourier series analysis. The sum rule for definite integrals of indexed sums is also formalized by applying the extended framework along with the First Fundamental Theorem of Calculus and the sum rule for differentiation. The Fourier coefficient formulas of periodic functions are then formalized from the orthogonality relations and the sum rule for integration. Consequently, the uniqueness of Fourier sums is a straightforward corollary. We also present our formalization of the sum rule for definite integrals of infinite series in ACL2(r. Part of this task is to prove the Dini Uniform Convergence Theorem and the continuity of a limit function under certain conditions. A key technique in our proofs of these theorems is to apply the overspill principle from non-standard analysis.
Fourier inversion on a reductive symmetric space
Ban, E.P. van den
2001-01-01
Let X be a semisimple symmetric space. In previous papers, [8] and [9], we have dened an explicit Fourier transform for X and shown that this transform is injective on the space C 1 c (X) ofcompactly supported smooth functions on X. In the present paper, which is a continuation of these papers, we e
Vector valued Fourier multipliers and applications
Directory of Open Access Journals (Sweden)
Davide Guidetti
2010-12-01
Full Text Available In questo seminario sono illustrati alcuni recenti sviluppi della teoria dei moltiplicatori di Fourier negli spazi L^p a valori in spazi di Banach. Seguono alcune applicazioni a problemi al contorno di tipo ellittico e a problemi misti di tipo parabolico.
Vector valued Fourier multipliers and applications
Davide Guidetti
2010-01-01
In questo seminario sono illustrati alcuni recenti sviluppi della teoria dei moltiplicatori di Fourier negli spazi L^p a valori in spazi di Banach. Seguono alcune applicazioni a problemi al contorno di tipo ellittico e a problemi misti di tipo parabolico.
On the Scaled Fractional Fourier Transformation Operator
Institute of Scientific and Technical Information of China (English)
FAN Hong-Yi; HU Li-Yun
2008-01-01
Based on our previous study [Chin.Phys.Lett.24(2007)2238]in which the Fresnel operator corresponding to classical Fresnel transform was introduced,we derive the fractional Fourier transformation operator,and the optical operator method is then enriched.
Fourier transforms on an amalgam type space
Liflyand, E
2012-01-01
We introduce an amalgam type space, a subspace of $L^1(\\mathbb R_+).$ Integrability results for the Fourier transform of a function with the derivative from such an amalgam space are proved. As an application we obtain estimates for the integrability of trigonometric series.
Fourier Analysis with Respect to Bilinear Maps
Institute of Scientific and Technical Information of China (English)
O.BLASCO; J.M.CALABUIG
2009-01-01
Several results about convolution and about Fourier coefficients for X-valued functions defined on the torus satisfying the condition sup‖y‖=1∫π-π‖B(f(eiθ),y)‖dθ/2π＜∞ for a bounded bilinear map B:X ×Y →Z are presented and some applications are given.
Harmonic oscillator: an analysis via Fourier series
de Castro, A S
2013-01-01
The Fourier series method is used to solve the homogeneous equation governing the motion of the harmonic oscillator. It is shown that the general solution to the problem can be found in a surprisingly simple way for the case of the simple harmonic oscillator. It is also shown that the damped harmonic oscillator is susceptible to the analysis.
Euler Polynomials, Fourier Series and Zeta Numbers
DEFF Research Database (Denmark)
Scheufens, Ernst E
2012-01-01
Fourier series for Euler polynomials is used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent series....
Bernoulli Polynomials, Fourier Series and Zeta Numbers
DEFF Research Database (Denmark)
Scheufens, Ernst E
2013-01-01
Fourier series for Bernoulli polynomials are used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent ...
Clifford Fourier transform on vector fields.
Ebling, Julia; Scheuermann, Gerik
2005-01-01
Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space.
Fourier transform infrared spectrometery: an undergraduate experiment
Lerner, L.
2016-11-01
Simple apparatus is developed, providing undergraduate students with a solid understanding of Fourier transform (FT) infrared (IR) spectroscopy in a hands on experiment. Apart from its application to measuring the mid-IR spectra of organic molecules, the experiment introduces several techniques with wide applicability in physics, including interferometry, the FT, digital data analysis, and control theory.
A Fourier analysis of extremal events
DEFF Research Database (Denmark)
Zhao, Yuwei
is the extremal periodogram. The extremal periodogram shares numerous asymptotic properties with the periodogram of a linear process in classical time series analysis: the asymptotic distribution of the periodogram ordinates at the Fourier frequencies have a similar form and smoothed versions of the periodogram...
Teaching Stable Two-Mirror Resonators through the Fractional Fourier Transform
Moreno, Ignacio; Garcia-Martinez, Pascuala; Ferreira, Carlos
2010-01-01
We analyse two-mirror resonators in terms of their fractional Fourier transform (FRFT) properties. We use the basic ABCD ray transfer matrix method to show how the resonator can be regarded as the cascade of two propagation-lens-propagation FRFT systems. Then, we present a connection between the geometric properties of the resonator (the g…
Welch, William R W; Keiderling, Timothy A; Kubelka, Jan
2013-09-12
In the preceding paper, computational models based on density functional theory (DFT) were presented to characterize the sensitivity of vibrational spectroscopic methods (IR, VCD, and Raman) to structural features of β-sheets. Isotopically edited amide I' IR for peptides labeled with (13)C in multiple different sites provides the most structurally distinct signatures of strand alignment, while VCD is sensitive to the sheet twist and intersheet stacking. In this report, we simulate the IR and VCD spectra for models approximating structures of four β-sheet forming peptides previously experimentally studied using these methods with (13)C isotopic editing. Various register alignments are tested. Agreement with experiment is evaluated based on frequency shifts of both the (12)C and (13)C IR amide I' signals, relative intensity patterns, and VCD spectra where available. While for the simulation of IR spectra canonical planar sheets provide a sufficient model system, for VCD simulation twisted, stacked sheets are required in order to reproduce strong couplet-like amide I' VCD. Effects of the solvent (water) and amino acid side chains are also tested by using a simplified, electrostatic solvent model and atomic partial charges for the side chains. Very good agreement with experimental spectra is obtained, particularly for the relative (12)C and (13)C band frequencies. All four peptide models are shown to be antiparallel as had previously been assumed. However, in some cases our simulations are consistent with different register alignment of strands than originally proposed.
Stan-Sion, C; Enachescu, M; Petre, A R
2015-05-01
This paper presents the results of an experimental study we performed by using the Accelerator Mass Spectrometry (AMS) method with iodine 129 (T1/2 = 15.7 My), to determine the increase of the radionuclide content in the USA West Pacific Coast waters, two years after the March 2011 Fukushima Daiichi nuclear power plant accident. The collection of the water samples took place between April and July 2013 at regular intervals of time, from the Pacific Ocean, at the cove of La Jolla, San Diego, USA. The results of the experiments showed a significant increase of the radionuclide concentration during the late spring of 2013. Compared to the isotopic ratio (129)I/(127)I, measured at a 40 km distance, offshore of Fukushima and immediately after the accident, our results show an increase on the USA West Coast that was more than a 2.5 factor higher. Also, compared with the pre-Fukushima background values, our results show an isotopic ratio of about two orders of magnitude higher. A distinct feature of the reconstructed radioactive plume was that it traveled with a speed of 12 cm s(-1), which we estimated and is consistent with the zonal speed in the Pacific. We coupled our (129)I results with the measurements from the June 2011 KOK cruise and we derived the levels of activity for (3)H and (137)Cs. On the USA West Coast, they did not exceed the international regulatory limits.
Nonlinear Fourier analysis with cnoidal waves
Energy Technology Data Exchange (ETDEWEB)
Osborne, A.R. [Dipt. di Fisica Generale dell`Universita, Torino (Italy)
1996-12-31
Fourier analysis is one of the most useful tools to the ocean engineer. The approach allows one to analyze wave data and thereby to describe a dynamical motion in terms of a linear superposition of ordinary sine waves. Furthermore, the Fourier technique allows one to compute the response function of a fixed or floating structure: each sine wave in the wave or force spectrum yields a sine wave in the response spectrum. The counting of fatigue cycles is another area where the predictable oscillations of sine waves yield procedures for the estimation of the fatigue life of structures. The ocean environment, however, is a source of a number of nonlinear effects which must also be included in structure design. Nonlinearities in ocean waves deform the sinusoidal shapes into other kinds of waves such as the Stokes wave, cnoidal wave or solitary wave. A key question is: Does there exist a generalization of linear Fourier analysis which uses nonlinear basis functions rather than the familiar sine waves? Herein addresses the dynamics of nonlinear wave motion in shallow water where the basis functions are cnoidal waves and discuss nonlinear Fourier analysis in terms of a linear superposition of cnoidal waves plus their mutual nonlinear interactions. He gives a number of simple examples of nonlinear Fourier wave motion and then analyzes an actual surface-wave time series obtained on an offshore platform in the Adriatic Sea. Finally, he briefly discusses application of the cnoidal wave spectral approach to the computation of the frequency response function of a floating vessel. The results given herein will prove useful in future engineering studies for the design of fixed, floating and complaint offshore structures.
Directory of Open Access Journals (Sweden)
Smith Derek
2009-01-01
Full Text Available Abstract Background iTRAQ is a proteomics technique that uses isobaric tags for relative and absolute quantitation of tryptic peptides. In proteomics experiments, the detection and high confidence annotation of proteins and the significance of corresponding expression differences can depend on the quality and the species specificity of the tryptic peptide map database used for analysis of the data. For species for which finished genome sequence data are not available, identification of proteins relies on similarity to proteins from other species using comprehensive peptide map databases such as the MSDB. Results We were interested in characterizing ripening initiation ('veraison' in grape berries at the protein level in order to better define the molecular control of this important process for grape growers and wine makers. We developed a bioinformatic pipeline for processing EST data in order to produce a predicted tryptic peptide database specifically targeted to the wine grape cultivar, Vitis vinifera cv. Cabernet Sauvignon, and lacking truncated N- and C-terminal fragments. By searching iTRAQ MS/MS data generated from berry exocarp and mesocarp samples at ripening initiation, we determined that implementation of the custom database afforded a large improvement in high confidence peptide annotation in comparison to the MSDB. We used iTRAQ MS/MS in conjunction with custom peptide db searches to quantitatively characterize several important pathway components for berry ripening previously described at the transcriptional level and confirmed expression patterns for these at the protein level. Conclusion We determined that a predicted peptide database for MS/MS applications can be derived from EST data using advanced clustering and trimming approaches and successfully implemented for quantitative proteome profiling. Quantitative shotgun proteome profiling holds great promise for characterizing biological processes such as fruit ripening
Hrle, Ajla; Maier, Lisa-Katharina; Sharma, Kundan; Ebert, Judith; Basquin, Claire; Urlaub, Henning; Marchfelder, Anita; Conti, Elena
2014-01-01
Upon pathogen invasion, bacteria and archaea activate an RNA-interference-like mechanism termed CRISPR (clustered regularly interspaced short palindromic repeats). A large family of Cas (CRISPR-associated) proteins mediates the different stages of this sophisticated immune response. Bioinformatic studies have classified the Cas proteins into families, according to their sequences and respective functions. These range from the insertion of the foreign genetic elements into the host genome to the activation of the interference machinery as well as target degradation upon attack. Cas7 family proteins are central to the type I and type III interference machineries as they constitute the backbone of the large interference complexes. Here we report the crystal structure of Thermofilum pendens Csc2, a Cas7 family protein of type I-D. We found that Csc2 forms a core RRM-like domain, flanked by three peripheral insertion domains: a lid domain, a Zinc-binding domain and a helical domain. Comparison with other Cas7 family proteins reveals a set of similar structural features both in the core and in the peripheral domains, despite the absence of significant sequence similarity. T. pendens Csc2 binds single-stranded RNA in vitro in a sequence-independent manner. Using a crosslinking - mass-spectrometry approach, we mapped the RNA-binding surface to a positively charged surface patch on T. pendens Csc2. Thus our analysis of the key structural and functional features of T. pendens Csc2 highlights recurring themes and evolutionary relationships in type I and type III Cas proteins.
Huang, Lin; Lange, Miles D; Zhang, Zhixin
2014-01-01
VH replacement occurs through RAG-mediated secondary recombination between a rearranged VH gene and an upstream unrearranged VH gene. Due to the location of the cryptic recombination signal sequence (cRSS, TACTGTG) at the 3' end of VH gene coding region, a short stretch of nucleotides from the previous rearranged VH gene can be retained in the newly formed VH-DH junction as a "footprint" of VH replacement. Such footprints can be used as markers to identify Ig heavy chain (IgH) genes potentially generated through VH replacement. To explore the contribution of VH replacement products to the antibody repertoire, we developed a Java-based computer program, VH replacement footprint analyzer-I (VHRFA-I), to analyze published or newly obtained IgH genes from human or mouse. The VHRFA-1 program has multiple functional modules: it first uses service provided by the IMGT/V-QUEST program to assign potential VH, DH, and JH germline genes; then, it searches for VH replacement footprint motifs within the VH-DH junction (N1) regions of IgH gene sequences to identify potential VH replacement products; it can also analyze the frequencies of VH replacement products in correlation with publications, keywords, or VH, DH, and JH gene usages, and mutation status; it can further analyze the amino acid usages encoded by the identified VH replacement footprints. In summary, this program provides a useful computation tool for exploring the biological significance of VH replacement products in human and mouse.
Determination of the Optimal Fourier Number on the Dynamic Thermal Transmission
Bruzgevičius, P.; Burlingis, A.; Norvaišienė, R.
2016-12-01
This article represents the result of experimental research on transient heat transfer in a multilayered (heterogeneous) wall. Our non-steady thermal transmission simulation is based on a finite-difference calculation method. The value of a Fourier number shows the similarity of thermal variation in conditional layers of an enclosure. Most scientists recommend using no more than a value of 0.5 for the Fourier number when performing calculations on dynamic (transient) heat transfer. The value of the Fourier number is determined in order to acquire reliable calculation results with optimal accuracy. To compare the results of simulation with experimental research, a transient heat transfer calculation spreadsheet was created. Our research has shown that a Fourier number of around 0.5 or even 0.32 is not sufficient ({≈ }17 % of oscillation amplitude) for calculations of transient heat transfer in a multilayered wall. The least distorted calculation results were obtained when the multilayered enclosure was divided into conditional layers with almost equal Fourier number values and when the value of the Fourier number was around 1/6, i.e., approximately 0.17. Statistical deviation analysis using the Statistical Analysis System was applied to assess the accuracy of the spreadsheet calculation and was developed on the basis of our established methodology. The mean and median absolute error as well as their confidence intervals has been estimated by the two methods with optimal accuracy ({F}_{oMDF}= 0.177 and F_{oEPS}= 0.1633 values).
Duda, David P.; Minnis, Patrick
2009-01-01
Straightforward application of the Schmidt-Appleman contrail formation criteria to diagnose persistent contrail occurrence from numerical weather prediction data is hindered by significant bias errors in the upper tropospheric humidity. Logistic models of contrail occurrence have been proposed to overcome this problem, but basic questions remain about how random measurement error may affect their accuracy. A set of 5000 synthetic contrail observations is created to study the effects of random error in these probabilistic models. The simulated observations are based on distributions of temperature, humidity, and vertical velocity derived from Advanced Regional Prediction System (ARPS) weather analyses. The logistic models created from the simulated observations were evaluated using two common statistical measures of model accuracy, the percent correct (PC) and the Hanssen-Kuipers discriminant (HKD). To convert the probabilistic results of the logistic models into a dichotomous yes/no choice suitable for the statistical measures, two critical probability thresholds are considered. The HKD scores are higher when the climatological frequency of contrail occurrence is used as the critical threshold, while the PC scores are higher when the critical probability threshold is 0.5. For both thresholds, typical random errors in temperature, relative humidity, and vertical velocity are found to be small enough to allow for accurate logistic models of contrail occurrence. The accuracy of the models developed from synthetic data is over 85 percent for both the prediction of contrail occurrence and non-occurrence, although in practice, larger errors would be anticipated.
Gereben, Orsolya; Pusztai, László
2015-02-19
Series of molecular dynamics simulations for ethanol-water mixtures with 20-80 mol % ethanol content, pure ethanol, and water were performed. In each mixture, for ethanol the OPLS force field was used, combined with three different water force fields, the SPC/E, the TIP4P-2005, and the SWM4-DP. Water potential models were distinguished on the basis of deviations between calculated and measured total scattering X-ray structure factors aided by ethanol-water pair binding energy comparison. No single water force field could provide the best agreement with experimental data at all concentrations: at the ethanol content of 80% the SWM-DP, for 60 mol % the SWM4-DP and the TIP4P-2005, whereas for the 40 and 20 mol % mixtures TIP4P-2005 water force field provided the closest match. Coordination numbers and hydrogen bonds/molecule values were calculated, revealing that the oxygen-oxygen first coordination numbers strongly overestimate the average number of hydrogen bonds/molecule. The center-of-molecule distributions indicate that the ethanol-ethanol first coordination sphere expands with increasing water concentration while the size of the first water-water coordination sphere does not change. Various two and three-dimensional distributions were calculated that reveal the differences between simulations with different water force fields. Detailed conformational analyses of the hydrogen-bonded pairs were performed; drawings of the characteristic molecular arrangements are provided.
Elliptic Fourier analysis of crown shapes in Quercus petraea trees
Directory of Open Access Journals (Sweden)
Ovidiu Hâruţa
2011-06-01
Full Text Available Shape is a fundamental morphological descriptor, significant in taxonomic research as well as in ecomorphology, one method of estimation being from digitally processed images. In the present study, were analysed shapes of Q. petraea crowns, pertaining to five different stem diameter classes, from three similar stands. Based on measurements on terrestrial digital vertical photos, crown size analysis was performed and correlations between crown and stem variables were tested. Linear regression equations between crown volumes and dbh, and crown volumes and stem volumes were derived, explaining more than half of data variability. Employment of elliptic Fourier analysis (EFA, a powerful analysis tool, permitted the extraction of the mean shape from crowns, characterized by high morphological variability. The extracted, most important, coefficients were used to reconstruct the average shape of the crowns, using Inverse Fourier Transform. A mean shape of the crown, corresponding to stand conditions in which competition is added as influential shaping factor, aside genetic program of the species, is described for each stem diameter class. Crown regions with highest shape variability, from the perspective of stage development of the trees, were determined. Accordingly, the main crown shape characteristics are: crown elongation, centroid position, asymmetry with regard to the main axis, lateral regions symmetrical and asymmetrical variations.
Elliptic Fourier analysis of crown shapes in Quercus petraea trees
Directory of Open Access Journals (Sweden)
Ovidiu Hâruţa
2011-02-01
Full Text Available Shape is a fundamental morphological descriptor, significant in taxonomic research as well as in ecomorphology, one method of estimation being from digitally processed images. In the present study, were analysed shapes of Q. petraea crowns, pertaining to five different stem diameter classes, from three similar stands. Based on measurements on terrestrial digital vertical photos, crown size analysis was performed and correlations between crown and stem variables were tested. Linear regression equations between crown volumes and dbh, and crown volumes and stem volumes were derived, explaining more than half of data variability. Employment of elliptic Fourier analysis (EFA, a powerful analysis tool, permitted the extraction of the mean shape from crowns, characterized by high morphological variability. The extracted, most important, coefficients were used to reconstruct the average shape of the crowns, using Inverse Fourier Transform. A mean shape of the crown, corresponding to stand conditions in which competition is added as influential shaping factor, aside genetic program of the species, is described for each stem diameter class. Crown regions with highest shape variability, from the perspective of stage developmentof the trees, were determined. Accordingly, the main crown shape characteristics are: crown elongation, mass center, asymmetry with regard to the main axis, lateral regions symmetrical and asymmetrical variations.
Fourier analysis: from cloaking to imaging
Wu, Kedi; Cheng, Qiluan; Wang, Guo Ping
2016-04-01
Regarding invisibility cloaks as an optical imaging system, we present a Fourier approach to analytically unify both Pendry cloaks and complementary media-based invisibility cloaks into one kind of cloak. By synthesizing different transfer functions, we can construct different devices to realize a series of interesting functions such as hiding objects (events), creating illusions, and performing perfect imaging. In this article, we give a brief review on recent works of applying Fourier approach to analysis invisibility cloaks and optical imaging through scattering layers. We show that, to construct devices to conceal an object, no constructive materials with extreme properties are required, making most, if not all, of the above functions realizable by using naturally occurring materials. As instances, we experimentally verify a method of directionally hiding distant objects and create illusions by using all-dielectric materials, and further demonstrate a non-invasive method of imaging objects completely hidden by scattering layers.
Laser Field Imaging Through Fourier Transform Heterodyne
Energy Technology Data Exchange (ETDEWEB)
Cooke, B.J.; Laubscher, B.E.; Olivas, N.L.; Galbraith, A.E.; Strauss, C.E.; Grubler, A.C.
1999-04-05
The authors present a detection process capable of directly imaging the transverse amplitude, phase, and Doppler shift of coherent electromagnetic fields. Based on coherent detection principles governing conventional heterodyned RADAR/LADAR systems, Fourier Transform Heterodyne incorporates transverse spatial encoding of the reference local oscillator for image capture. Appropriate selection of spatial encoding functions allows image retrieval by way of classic Fourier manipulations. Of practical interest: (1) imaging may be accomplished with a single element detector/sensor requiring no additional scanning or moving components, (2) as detection is governed by heterodyne principles, near quantum limited performance is achievable, (3) a wide variety of appropriate spatial encoding functions exist that may be adaptively configured in real-time for applications requiring optimal detection, and (4) the concept is general with the applicable electromagnetic spectrum encompassing the RF through optical.
Fourier series expansion for nonlinear Hamiltonian oscillators.
Méndez, Vicenç; Sans, Cristina; Campos, Daniel; Llopis, Isaac
2010-06-01
The problem of nonlinear Hamiltonian oscillators is one of the classical questions in physics. When an analytic solution is not possible, one can resort to obtaining a numerical solution or using perturbation theory around the linear problem. We apply the Fourier series expansion to find approximate solutions to the oscillator position as a function of time as well as the period-amplitude relationship. We compare our results with other recent approaches such as variational methods or heuristic approximations, in particular the Ren-He's method. Based on its application to the Duffing oscillator, the nonlinear pendulum and the eardrum equation, it is shown that the Fourier series expansion method is the most accurate.
Saturated pattern-illuminated Fourier ptychography microscopy
Fang, Yue; Chen, Youhua; Kuang, Cuifang; Xiu, Peng; Liu, Qiulan; Ge, Baoliang; Liu, Xu
2017-01-01
We report a series of simulation studies which extends pattern-illuminated Fourier ptychography microscopy by integrating with the nonlinearity arising from saturation of the fluorophore excited state for super-resolution fluorescence imaging. This extended technique, termed Saturated pattern-illuminated Fourier ptychography (SpiFP) microscopy, could achieve a resolution four times that of wide field when the illuminating light intensity approaches the saturation threshold in simulations. Increasing light intensity leads to further resolution enhancement. In order to demonstrate the performance of SpiFP, we make a comparison between SpiFP and saturated structure illumination microscopy in simulations, and prove that the SpiFP exhibits superior robustness to noise, aberration correcting ability, and pattern’s flexibility. Introducing the saturation of the fluorescent emission brings in notable improvements in imaging performance, implying its potential in nanoscale-sized biological observations by wide-field microscopy.
Weaving defect detection by Fourier imaging
Ciamberlini, Claudio; Francini, Franco; Longobardi, Giuseppe; Poggi, Pasquale; Sansoni, Paola; Tiribilli, Bruno
1996-08-01
An optical configuration for the detection of faults was developed and tested. The optical fourier transformation is the basic working principle of the system. When good fabric passes in front of the optical system the Fourier image, captured by the camera, shows well defined spots corresponding to the spatial frequencies of the tissue. If a defect occurs during production on the loom, the pattern changes significantly and a defect is easily detected in real time. A very simple electronic image processing based on thresholding and binary histograms allows to obtain very encouraging performance for its applicability to the looms. A compact device has been realized and tested in real working conditions on the loom.
Digital Backpropagation in the Nonlinear Fourier Domain
Wahls, Sander; Prilepsky, Jaroslaw E; Poor, H Vincent; Turitsyn, Sergei K
2015-01-01
Nonlinear and dispersive transmission impairments in coherent fiber-optic communication systems are often compensated by reverting the nonlinear Schr\\"odinger equation, which describes the evolution of the signal in the link, numerically. This technique is known as digital backpropagation. Typical digital backpropagation algorithms are based on split-step Fourier methods in which the signal has to be discretized in time and space. The need to discretize in both time and space however makes the real-time implementation of digital backpropagation a challenging problem. In this paper, a new fast algorithm for digital backpropagation based on nonlinear Fourier transforms is presented. Aiming at a proof of concept, the main emphasis will be put on fibers with normal dispersion in order to avoid the issue of solitonic components in the signal. However, it is demonstrated that the algorithm also works for anomalous dispersion if the signal power is low enough. Since the spatial evolution of a signal governed by the ...
X-ray Fourier ptychographic microscopy
Simons, H; Guigay, J P; Detlefs, C
2016-01-01
Following the recent developement of Fourier ptychographic microscopy (FPM) in the visible range by Zheng et al. (2013), we propose an adaptation for hard x-rays. FPM employs ptychographic reconstruction to merge a series of low-resolution, wide field of view images into a high-resolution image. In the x-ray range this opens the possibility to overcome the limited numerical aperture of existing x-ray lenses. Furthermore, digital wave front correction (DWC) may be used to charaterize and correct lens imperfections. Given the diffraction limit achievable with x-ray lenses (below 100 nm), x-ray Fourier ptychographic microscopy (XFPM) should be able to reach resolutions in the 10 nm range.
High order generalized permutational fractional Fourier transforms
Institute of Scientific and Technical Information of China (English)
Ran Qi-Wen; Yuan Lin; Tan Li-Ying; Ma Jing; Wang Qi
2004-01-01
We generalize the definition of the fractional Fourier transform (FRFT) by extending the new definition proposed by Shih. The generalized FRFT, called the high order generalized permutational fractional Fourier transform (HGPFRFT),is a generalized permutational transform. It is shown to have arbitrary natural number M periodic eigenvalues not only with respect to the order of Hermite-Gaussian functions but also to the order of the transform. This HGPFRFT will be reduced to the original FRFT proposed by Namias and Liu's generalized FRFT and Shih's FRFT at the three limits with M = +∞,M = 4k (k is a natural number), and M = 4, respectively. Therefore the HGPFRFT introduces a comprehensive approach to Shih's FRFT and the original definition. Some important properties of HGPFRFT are discussed. Lastly the results of computer simulations and symbolic representations of the transform are provided.
Fourier Transform Fabry-Perot Interferometer
Snell, Hilary E.; Hays, Paul B.
1992-01-01
We are developing a compact, rugged, high-resolution remote sensing instrument with wide spectral scanning capabilities. This relatively new type of instrument, which we have chosen to call the Fourier-Transform Fabry-Perot Interferometer (FT-FPI), is accomplished by mechanically scanning the etalon plates of a Fabry-Perot interferometer (FPI) through a large optical distance while examining the concomitant signal with a Fourier-transform analysis technique similar to that employed by the Michelson interferometer. The FT-FPI will be used initially as a ground-based instrument to study near-infrared atmospheric absorption lines of trace gases using the techniques of solar absorption spectroscopy. Future plans include modifications to allow for measurements of trace gases in the stratosphere using spectral lines at terahertz frequencies.
Computing Fourier integral operators with caustics
Caday, Peter
2016-12-01
Fourier integral operators (FIOs) have widespread applications in imaging, inverse problems, and PDEs. An implementation of a generic algorithm for computing FIOs associated with canonical graphs is presented, based on a recent paper of de Hoop et al. Given the canonical transformation and principal symbol of the operator, a preprocessing step reduces application of an FIO approximately to multiplications, pushforwards and forward and inverse discrete Fourier transforms, which can be computed in O({N}n+(n-1)/2{log}N) time for an n-dimensional FIO. The same preprocessed data also allows computation of the inverse and transpose of the FIO, with identical runtime. Examples demonstrate the algorithm’s output, and easily extendible MATLAB/C++ source code is available from the author.
Fourier Transform Infrared Spectroscopic Studies in Flotation
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Fourier transform infrared (FTIR) spectroscopy has been extensively employed in flotation research.The work done by the author and co-workers has been reported.A comparison has been made among the different FTIR spectroscopic techniques,e.g.,transmission FTIR spectroscopy,diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy,and attenuated total reflectance (ATR) FTIR spectroscopy.FTIR spectroscopy has been used to study the mechanism of interaction between the collector and the surfaces of different minerals,the mechanism of action of the depressant in improving the selectivity of flotation,and the mechanism of adsorption of the polymeric modifying reagent on mineral surfaces.The interaction between particles in mineral suspension has also been studied by FTIR spectroscopy.
Fourier and wavelet spectral analysis of EMG signals in supramaximal constant load dynamic exercise.
Camata, Thiago V; Dantas, Jose L; Abrao, Taufik; Brunetto, Maria A C; Moraes, Antonio C; Altimari, Leandro R
2010-01-01
Frequency domain analyses of changes in electromyographic (EMG) signals over time are frequently used to assess muscle fatigue. Fourier based approaches are typically used in these analyses, yet Fourier analysis assumes signal stationarity, which is unlikely during dynamic contractions. Wavelet based methods of signal analysis do not assume stationarity and may be more appropriate for joint time-frequency domain analysis. The purpose of this study was to compare Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT) in assessing muscle fatigue in supramaximal constant load dynamic exercise (110% VO(2peak)). The results of this study indicate that CWT and STFT analyses give similar fatigue estimates (slope of median frequency) in supramaximal constant load dynamic exercise (P>0.05). However, the results of the variance was significantly lower for at least one of the muscles studied in CWT compared to STFT (P signal analysis using STFT. Thus, the stationarity assumption may not be the sole factor responsible for affecting the Fourier based estimates.
Fourier and wavelet spectral analysis of EMG signals in maximal constant load dynamic exercise.
Costa, Marcelo V; Pereira, Lucas A; Oliveira, Ricardo S; Pedro, Rafael E; Camata, Thiago V; Abrao, Taufik; Brunetto, Maria A C; Altimari, Leandro R
2010-01-01
Frequency domain analyses of changes in electromyographic (EMG) signals over time are frequently used to assess muscle fatigue. Fourier based approaches are typically used in these analyses, yet Fourier analysis assumes signal stationarity, which is unlikely during dynamic contractions. Wavelet based methods of signal analysis do not assume stationarity and may be more appropriate for joint time-frequency domain analysis. The purpose of this study was to compare Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT) in assessing muscle fatigue in maximal constant load dynamic exercise (100% W(max)). The results of this study indicate that CWT and STFT analyses give similar fatigue estimates (slope of median frequency) in maximal constant load dynamic exercise (P>0.05). However, the results of the variance was significantly lower for at least one of the muscles studied in CWT compared to STFT (P〈0.05) indicating more variability in the EMG signal analysis using STFT. Thus, the stationarity assumption may not be the sole factor responsible for affecting the Fourier based estimates.
Interferometric measurement of charged particle spectra (Fourier-spectroscopy)
Energy Technology Data Exchange (ETDEWEB)
Hasselbach, F. [Tuebingen Univ. (Germany). Inst. fuer Angewandte Physik; Schaefer, A. [Tuebingen Univ. (Germany). Inst. fuer Angewandte Physik; Wachendorfer, H. [Tuebingen Univ. (Germany). Inst. fuer Angewandte Physik
1995-09-01
Fourier spectroscopy, the most fundamental and, at least in principle, the most precise spectroscopy method, has been introduced by A.A. Michelson at the end of the last century. The method was restricted to electromagnetic waves until an optical component to shift the interfering wave packets longitudinally was invented [G. Moellensted and G. Wohland, Electron Microscopy 1980, eds. P. Bredoro and G. Boom, 7th Europ. Congr. on Electron Microscopy Foundation, Leiden, Vol. 1, p. 28] and refined [H. Gauch, Diploma thesis, University Tuebingen (1983); I. Daberkow et al., Joint Meeting on Electron Microscopy, Antwerp, Belgium, 1983, Program and Abstract Book, p. 100] to such a degree of perfection that the longitudinal shift could be controlled to a fraction of a percent of the wavelength. The Fourier spectrometer for charged matter waves is made up by a wave front splitting electron optical biprism in combination with crossed electric and magnetic fields (Wien-filter) as a wave-packet-shifting device. The contrast of the interference fringes as a function of the longitudinal shift is recorded by a CCD-line-camera, transferred to a PC and Fourier analyzed subsequently. As an example the spectrum of a field emission electron source was analyzed. At an energy of the electrons of 1 keV about 12 000 fringes with a contrast exceeding 10% were recorded. The measured full width at half maximum was 0.6 eV{+-}80 meV. The total error of 80 meV contains 40 meV error due to insufficient sampling of data and 40 meV since about 2000 low contrast fringes were neglected. The action of crossed electric and magnetic fields on electron wave packets including the major problems arising from their weak focusing action for the new method of spectroscopy is discussed extensively. (orig.).
Exponential Approximations Using Fourier Series Partial Sums
Banerjee, Nana S.; Geer, James F.
1997-01-01
The problem of accurately reconstructing a piece-wise smooth, 2(pi)-periodic function f and its first few derivatives, given only a truncated Fourier series representation of f, is studied and solved. The reconstruction process is divided into two steps. In the first step, the first 2N + 1 Fourier coefficients of f are used to approximate the locations and magnitudes of the discontinuities in f and its first M derivatives. This is accomplished by first finding initial estimates of these quantities based on certain properties of Gibbs phenomenon, and then refining these estimates by fitting the asymptotic form of the Fourier coefficients to the given coefficients using a least-squares approach. It is conjectured that the locations of the singularities are approximated to within O(N(sup -M-2), and the associated jump of the k(sup th) derivative of f is approximated to within O(N(sup -M-l+k), as N approaches infinity, and the method is robust. These estimates are then used with a class of singular basis functions, which have certain 'built-in' singularities, to construct a new sequence of approximations to f. Each of these new approximations is the sum of a piecewise smooth function and a new Fourier series partial sum. When N is proportional to M, it is shown that these new approximations, and their derivatives, converge exponentially in the maximum norm to f, and its corresponding derivatives, except in the union of a finite number of small open intervals containing the points of singularity of f. The total measure of these intervals decreases exponentially to zero as M approaches infinity. The technique is illustrated with several examples.
Fourier-transform spectroscopy instrumentation engineering
Saptari, Vidi
2003-01-01
Many applications today require the Fourier-transform (FT) spectrometer to perform close to its limitations, such as taking many quantitative measurements in the visible and in the near infrared wavelength regions. In such cases, the instrument should not be considered as a perfect ""black box."" Knowing where the limitations of performance arise and which components must be improved are crucial to obtaining repeatable and accurate results. One of the objectives of this book is to help the user identify the instrument's bottleneck.
Hyperbolicity of semigroups and Fourier multipliers
Latushkin, Yuri; Shvidkoy, Roman
2001-01-01
We present a characterization of hyperbolicity for strongly continuous semigroups on Banach spaces in terms of Fourier multiplier properties of the resolvent of the generator. Hyperbolicity with respect to classical solutions is also considered. Our approach unifies and simplifies the M. Kaashoek-- S. Verduyn Lunel theory and multiplier-type results previously obtained by S. Clark, M. Hieber, S. Montgomery-Smith, F. R\\"{a}biger, T. Randolph, and L. Weis.
A Fourier analysis of extreme events
DEFF Research Database (Denmark)
Mikosch, Thomas Valentin; Zhao, Yuwei
2014-01-01
The extremogram is an asymptotic correlogram for extreme events constructed from a regularly varying stationary sequence. In this paper, we define a frequency domain analog of the correlogram: a periodogram generated from a suitable sequence of indicator functions of rare events. We derive basic ...... properties of the periodogram such as the asymptotic independence at the Fourier frequencies and use this property to show that weighted versions of the periodogram are consistent estimators of a spectral density derived from the extremogram....
Cheung, Imelda W Y; Nakayama, Satoko; Hsu, Monica N K; Samaranayaka, Anusha G P; Li-Chan, Eunice C Y
2009-10-14
The potential for producing antihypertensive peptides from oat proteins through enzymatic hydrolysis was assessed in silico and confirmed in vitro. Thermolysin (EC 3.4.24.27) was predicted using BIOPEP database as the enzyme that would theoretically produce the most angiotensin I converting enzyme (ACE) inhibitory peptides from oat. Experimental evidence confirmed that strong ACE-inhibitory activity was produced under various hydrolysis conditions. Hydrolysates produced under high enzyme-to-substrate ratio (3%) short time (20 min) (HEST) and low enzyme-to-substrate ratio (0.1%) long time (120 min) (LELT) conditions had IC(50) values of 30 and 50 microg/mL, respectively. After simulated gastrointestinal digestion, the IC(50) of the HEST hydrolysate was 35 microg/mL whereas the IC(50) of the LELT hydrolysate was higher at 85 microg/mL. Ultrafiltration revealed that potent ACE-inhibitory peptides had molecular weights below 3 kDa. This study demonstrates the usefulness of in silico analysis to select enzymes for hydrolysis of proteins not previously examined as sources of bioactive peptides.
The Asymmetric Pupil Fourier Wavefront Sensor
Martinache, Frantz
2013-01-01
This paper introduces a novel wavefront sensing approach that relies on the Fourier analysis of a single conventional direct image. In the high Strehl ratio regime, the relation between the phase measured in the Fourier plane and the wavefront errors in the pupil can be linearized, as was shown in a previous work that introduced the notion of generalized closure-phase, or kernel-phase. The technique, to be usable as presented requires two conditions to be met: (1) the wavefront errors must be kept small (of the order of one radian or less) and (2) the pupil must include some asymmetry, that can be introduced with a mask, for the problem to become solvable. Simulations show that this asymmetric pupil Fourier wavefront sensing or APF-WFS technique can improve the Strehl ratio from 50 to over 90 % in just a few iterations, with excellent photon noise sensitivity properties, suggesting that on-sky close loop APF-WFS is possible with an extreme adaptive optics system.
Matrix isolation studies with Fourier transform IR
Energy Technology Data Exchange (ETDEWEB)
Green, David W.; Reedy, Gerald T.
1977-01-01
The combination of Fourier transform infrared (FT-IR) spectroscopy with the matrix-isolation techniques has advantages compared with the use of more conventional grating spectroscopy. Furthermore, the recent commercial availability of Fourier transform spectrometers has made FT-IR a practical alternative. Some advantages of the FT-IR spectrometer over the grating spectrometer are the result of the computerized data system that is a necessary part of the FT-IR spectrometer; other advantages are a consequence of the difference in optical arrangements and these represent the inherent advantages of the FT-IR method. In most applications with the matrix-isolation technique, the use of FT-IR spectroscopy results in either an improved signal-to-noise ratio or a shorter time for data collection compared with grating infrared spectroscopy. Fourier transform infrared spectroscopy has been used in the laboratory to study several molecular species in low-temperature matrices. Some species have been produced by high-temperature vaporization from Knudsen cells and others by sputtering. By sputtering, Ar and Kr matrices have been prepared which contain U atoms, UO, UO/sub 2/, UO/sub 3/, PuO, PuO/sub 2/, UN, or UN/sub 2/, depending upon the composition of the gas used to sputter as well as the identity of the metallic cathode. Infrared spectra of matrices containing these compounds are presented and discussed. (JRD)
Turbulence on a Fractal Fourier set
Lanotte, Alessandra Sabina; Biferale, Luca; Malapaka, Shiva Kumar; Toschi, Federico
2015-01-01
The dynamical effects of mode reduction in Fourier space for three dimensional turbulent flows is studied. We present fully resolved numerical simulations of the Navier-Stokes equations with Fourier modes constrained to live on a fractal set of dimension D. The robustness of the energy cascade and vortex stretching mechanisms are tested at changing D, from the standard three dimensional case to a strongly decimated case for D = 2.5, where only about $3\\%$ of the Fourier modes interact. While the direct energy cascade persist, deviations from the Kolmogorov scaling are observed in the kinetic energy spectra. A model in terms of a correction with a linear dependency on the co-dimension of the fractal set, $E(k)\\sim k^{- 5/3 + 3 -D }$, explains the results. At small scales, the intermittent behaviour due to the vorticity production is strongly modified by the fractal decimation, leading to an almost Gaussian statistics already at D ~ 2.98. These effects are connected to a genuine modification in the triad-to-tri...
Energy Technology Data Exchange (ETDEWEB)
Faehn, Taran; Jacobsen, Karl
2012-11-01
We report results from analyses performed for the Ministry of Finance and the Ministry of the Environment of specified climate policy scenarios. The results are computed by means of the model MSG-TECH, which is a computable general equilibrium model that allows for technological abatement options. All the scenarios model the participation in EU emissions trading scheme (ETS), which implies obligations of the firms to mitigate or purchase allowances. The scenarios also include the Kyoto commitments and the Norwegian government's pledges in the wake of the Copenhagen negotiations 2010 to reduce domestic emissions by 30 per cent and 100 per cent by 2020 and 2050, respectively. These ambitions can be met by exploiting international green mechanisms like CDM project funding. The studied scenarios differ in their assumptions about domestic emission prices. None of the scenarios obtain the ambitions set by the Parliament's Climate Agreement in 2008, corresponding to reductions of between 12 and 14 million tons from the reference in 2020. The most ambitious regime in this analysis results in a cut of 4.3 million tons CO{sub 2} equivalents in 2020, while the least ambitious obtains 1.6 million abated tons. In 2050 the cuts constitute between 5.8 and 8.9 million tons CO{sub 2} equivalents. The scenarios P10 and P20 assume a uniform carbon price of all Kyoto gas emissions (except emissions from agriculture). In the former, the uniform price corresponds to the estimated global marginal costs of avoiding a temperature increase above two degrees C. It is operationalised to 280 Nok in 2020 and 1020 Nok in 2050, respectively (in real 2011-prices). This implies that EU ETS sources pay a tax on top of the ETS price that equalise the carbon price within the rest of the economy. This scenario results in a domestic abatement of 2.0 million tons in 2020 and 8.9 million tons in 2050. In the second scenario, the uniform carbon price is assumed to increase faster until 2020
Sammler, Svenja; Ketmaier, Valerio; Havenstein, Katja; Krause, Ulrike; Curio, Eberhard; Tiedemann, Ralph
2012-10-12
The Visayan Tarictic Hornbill (Penelopides panini) and the Walden's Hornbill (Aceros waldeni) are two threatened hornbill species endemic to the western islands of the Visayas that constitute - between Luzon and Mindanao - the central island group of the Philippine archipelago. In order to evaluate their genetic diversity and to support efforts towards their conservation, we analyzed genetic variation in ~ 600 base pairs (bp) of the mitochondrial control region I and at 12-19 nuclear microsatellite loci. The sampling covered extant populations, still occurring only on two islands (P. panini: Panay and Negros, A. waldeni: only Panay), and it was augmented with museum specimens of extinct populations from neighboring islands. For comparison, their less endangered (= more abundant) sister taxa, the Luzon Tarictic Hornbill (P. manillae) from the Luzon and Polillo Islands and the Writhed Hornbill (A. leucocephalus) from Mindanao Island, were also included in the study. We reconstructed the population history of the two Penelopides species and assessed the genetic population structure of the remaining wild populations in all four species. Mitochondrial and nuclear data concordantly show a clear genetic separation according to the island of origin in both Penelopides species, but also unravel sporadic over-water movements between islands. We found evidence that deforestation in the last century influenced these migratory events. Both classes of markers and the comparison to museum specimens reveal a genetic diversity loss in both Visayan hornbill species, P. panini and A. waldeni, as compared to their more abundant relatives. This might have been caused by local extinction of genetically differentiated populations together with the dramatic decline in the abundance of the extant populations. We demonstrated a loss in genetic diversity of P. panini and A. waldeni as compared to their sister taxa P. manillae and A. leucocephalus. Because of the low potential for gene flow
ON SOME APPLICATIONS OF AN INTEGRATED FOURIER SERIES,
The problem of absolute convergence of Fourier series and of uniform convergence factors is considered. A theorem on the estimation of Fourier coefficients under the condition that they are positive is proved. (Author)
The derivative-free Fourier shell identity for photoacoustics.
Baddour, Natalie
2016-01-01
In X-ray tomography, the Fourier slice theorem provides a relationship between the Fourier components of the object being imaged and the measured projection data. The Fourier slice theorem is the basis for X-ray Fourier-based tomographic inversion techniques. A similar relationship, referred to as the 'Fourier shell identity' has been previously derived for photoacoustic applications. However, this identity relates the pressure wavefield data function and its normal derivative measured on an arbitrary enclosing aperture to the three-dimensional Fourier transform of the enclosed object evaluated on a sphere. Since the normal derivative of pressure is not normally measured, the applicability of the formulation is limited in this form. In this paper, alternative derivations of the Fourier shell identity in 1D, 2D polar and 3D spherical polar coordinates are presented. The presented formulations do not require the normal derivative of pressure, thereby lending the formulas directly adaptable for Fourier based absorber reconstructions.
A New Condition for the Uniform Convergence in Fourier Analysis
Institute of Scientific and Technical Information of China (English)
周颂平; 乐瑞君
2004-01-01
@@ In Fourier analysis, since Fourier coefficients are computable and applicable, people have already established many nice results by assuming monotonicty of the coefficients. One famous classical result is done by Chaundy and Jolliffe[1] as follows:
Fractional Fourier transform of Cantor sets: further numerical study
Institute of Scientific and Technical Information of China (English)
Gao Qiong; Liao tian-He; Cui Yuan-Feng
2008-01-01
This paper is a further work of the authors' paper published previously (Liao T H and Gao Q 2005 Chin. Phys. Lett. 22 2316). The amplitudes of fractional Fourier transform of Cantor sets are analysed from the viewpoint of multifractal by wavelet transform maxima method (WTMM). An integral operation is carried out before the application of WTMM, such that the function obtained can be considered as the perturbed devil staircase. Also, wavelets with large number of vanishing moments are used, which makes the complete singularity spectrum more accessible. The validity of multifractal formalism is guaranteed by restricting parameter q to a proper range, so that the phenomenon of multifractal phase transition can be explained reasonably. Particularly, the method of determining the range of parameter q in the above paper is developed to be more operational and rigorous.
The RC Circuit: An Approach with Fourier Transforms
Indian Academy of Sciences (India)
2016-11-01
In this article we shall mathematically analyse the Resistor-Capacitor (RC) circuit with the help of Fourier transforms(FT). This very general technique gives us a lot of insight intosolving first order differential equations with source terms dependingon time. In itself, the RC circuit is by far the mostcommonplace entity in modern electronics. But the method ofFT is not the accepted custom for an electronic engineer, whois probably more comfortable working with complex impedancesand phasors while solving problems in network analysis.In fact, what is used much more extensively is the Laplacetransform. But a lot of things, (including the complex impedanceitself, and some insight into complex analysis) can be understoodbetter if we use the FT approach to solve the differentialequations that come up in network analysis. The use of FTcomes smoothly from first principles – precisely what we setout to demonstrate here.
Fourier optics for polymeric substrates and coating textures analysis
Sparavigna, Amelia
2008-01-01
Several devices for substrate texture detection based on diffractive optics, for paper, textiles and non-wovens have been proposed in the past for direct inspection during the production processes. In spite of the presence of devices totally based on image processing, the use of diffractive optics cannot be considered surpassed for many reasons. Compared with image processing procedures, it is less sensitive to vibrations and does not suffer from the presence of ambient light. Based on transmitted light, it can give information on changes in refractive indexes, thickness variation and surface conditions. We study the use of optical Fourier spectrum to identify textures of polymer films. As the power spectrum reveals, the texture is seldom homogeneous. Here we report investigation on several substrates and on thin ink coatings on substrate. Role of bulk and surface conditions is analysed.
Instrument concept of the imaging Fourier transform spectrometer GLORIA
Directory of Open Access Journals (Sweden)
F. Friedl-Vallon
2014-10-01
Full Text Available The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA is an imaging limb emission sounder operating in the thermal infrared region. It is designed to provide measurements of the upper troposphere/lower stratosphere with high spatial and high spectral resolution. The instrument consists of an imaging Fourier transform spectrometer integrated into a gimbal. The assembly can be mounted in the belly pod of the German High Altitude and Long Range research aircraft (HALO and in instrument bays of the Russian M55 Geophysica. Measurements are made in two distinct modes: the chemistry mode emphasises chemical analysis with high spectral resolution, and the dynamics mode focuses on dynamical processes of the atmosphere with very high spatial resolution. In addition, the instrument allows tomographic analyses of air volumes. The first measurement campaigns have shown compliance with key performance and operational requirements.
Rejection of Linear FM Interference in DSSS System Based on Fractional Fourier Transform
Institute of Scientific and Technical Information of China (English)
QI Lin; TAO Ran; ZHOU Si-yong
2005-01-01
A new method for the rejection of linear frequency modulation (LFM) interference in direct sequence spread spectrum (DSSS) system based on the fractional Fourier transform is proposed, and the configuration of the receiver with an interference exciser is also presented. Based on the property that the fractional Fourier transform of a signal is equivalent to rotating the signal in the time-frequency plane, the received signal is transform into a certain fractional Fourier domain, this transform will result in the least spectrum overlap between the signal and interference. Then, a narrowband filter is exploited to extract most of the interference energy. The performance analyses show that remarkable improvements in signal-to-noise ratio (SNR) and biterror-ratio (BER) are obtained.
Directory of Open Access Journals (Sweden)
Sammler Svenja
2012-10-01
Full Text Available Abstract Background The Visayan Tarictic Hornbill (Penelopides panini and the Walden’s Hornbill (Aceros waldeni are two threatened hornbill species endemic to the western islands of the Visayas that constitute - between Luzon and Mindanao - the central island group of the Philippine archipelago. In order to evaluate their genetic diversity and to support efforts towards their conservation, we analyzed genetic variation in ~ 600 base pairs (bp of the mitochondrial control region I and at 12–19 nuclear microsatellite loci. The sampling covered extant populations, still occurring only on two islands (P. panini: Panay and Negros, A. waldeni: only Panay, and it was augmented with museum specimens of extinct populations from neighboring islands. For comparison, their less endangered (= more abundant sister taxa, the Luzon Tarictic Hornbill (P. manillae from the Luzon and Polillo Islands and the Writhed Hornbill (A. leucocephalus from Mindanao Island, were also included in the study. We reconstructed the population history of the two Penelopides species and assessed the genetic population structure of the remaining wild populations in all four species. Results Mitochondrial and nuclear data concordantly show a clear genetic separation according to the island of origin in both Penelopides species, but also unravel sporadic over-water movements between islands. We found evidence that deforestation in the last century influenced these migratory events. Both classes of markers and the comparison to museum specimens reveal a genetic diversity loss in both Visayan hornbill species, P. panini and A. waldeni, as compared to their more abundant relatives. This might have been caused by local extinction of genetically differentiated populations together with the dramatic decline in the abundance of the extant populations. Conclusions We demonstrated a loss in genetic diversity of P. panini and A. waldeni as compared to their sister taxa P. manillae and A
Experimental robustness of Fourier Ptychography phase retrieval algorithms
Yeh, Li-Hao; Zhong, Jingshan; Tian, Lei; Chen, Michael; Tang, Gongguo; Soltanolkotabi, Mahdi; Waller, Laura
2015-01-01
Fourier ptychography is a new computational microscopy technique that provides gigapixel-scale intensity and phase images with both wide field-of-view and high resolution. By capturing a stack of low-resolution images under different illumination angles, a nonlinear inverse algorithm can be used to computationally reconstruct the high-resolution complex field. Here, we compare and classify multiple proposed inverse algorithms in terms of experimental robustness. We find that the main sources of error are noise, aberrations and mis-calibration (i.e. model mis-match). Using simulations and experiments, we demonstrate that the choice of cost function plays a critical role, with amplitude-based cost functions performing better than intensity-based ones. The reason for this is that Fourier ptychography datasets consist of images from both brightfield and darkfield illumination, representing a large range of measured intensities. Both noise (e.g. Poisson noise) and model mis-match errors are shown to scale with int...
Gradient-based image recovery methods from incomplete Fourier measurements.
Patel, Vishal M; Maleh, Ray; Gilbert, Anna C; Chellappa, Rama
2012-01-01
A major problem in imaging applications such as magnetic resonance imaging and synthetic aperture radar is the task of trying to reconstruct an image with the smallest possible set of Fourier samples, every single one of which has a potential time and/or power cost. The theory of compressive sensing (CS) points to ways of exploiting inherent sparsity in such images in order to achieve accurate recovery using sub-Nyquist sampling schemes. Traditional CS approaches to this problem consist of solving total-variation (TV) minimization programs with Fourier measurement constraints or other variations thereof. This paper takes a different approach. Since the horizontal and vertical differences of a medical image are each more sparse or compressible than the corresponding TV image, CS methods will be more successful in recovering these differences individually. We develop an algorithm called GradientRec that uses a CS algorithm to recover the horizontal and vertical gradients and then estimates the original image from these gradients. We present two methods of solving the latter inverse problem, i.e., one based on least-square optimization and the other based on a generalized Poisson solver. After a thorough derivation of our complete algorithm, we present the results of various experiments that compare the effectiveness of the proposed method against other leading methods.
High Etendue Imaging Fourier Transform Spectrometer: initial results
Horton, Richard F.; Conger, Chris A.; Pelligrino, L. S.
1997-10-01
At the Denver meeting, last year, we presented the High Etendue Imaging Fourier Transform Spectrometer, (HEIFTS), theory and optical design. This device uses a new 'image plane interferometer' geometry to produce 'autocorrelation function modulation' in the image plane of a 2D imaging array, such that the phase offset of the modulation varies linearly across the image. As a 2D image is pushbroomed across the imaging, array, the record of an individual scene pixel is recorded for each autocorrelation phase offset. The 3D array of this data is processed to yield an 'autocorrelation function' data cube, which is Fourier transformed to yield a 'wavenumber' hyperspectral data curve. A phase I device has been demonstrated in the laboratory and initial results are presented. The significant increase in signal to noise ratio, which the HEIFTS optical design promises over conventional hyperspectral imaging schemes, has been simulated, and results will be discussed. A Phase II system is being prepared for initial field deployment, and will be described.
Integrated optics in an electrically scanned imaging Fourier transform spectrometer
Breckinridge, James B. (Inventor); Ocallaghan, Fred G. (Inventor)
1982-01-01
An efficient, lightweight and stable, Fourier transform spectrometer was developed. The mechanical slide mechanism needed to create a path difference was eliminated by the use of retro-reflecting mirrors in a monolithic interferometer assembly in which the mirrors are not at 90 degrees to the propagation vector of the radiation, but rather at a small angle. The resulting plane wave fronts create a double-sided inteferogram of the source irradiance distribution which is detected by a charge-coupled device image sensor array. The position of each CCD pixel in the array is an indication of the path difference between the two retro-reflecting mirrors in the monolithic optical structure. The Fourier transform of the signals generated by the image sensor provide the spectral irradiance distribution of the source. For imaging, the interferometer assembly scans the source of irradiation by moving the entire instrument, such as would occur if it was fixedly mounted to a moving platform, i.e., a spacecraft. During scanning, the entrace slot to the monolithic optical structure sends different pixels to corresponding interferograms detected by adjacent columns of pixels of the image sensor.
Research progress on discretization of fractional Fourier transform
Institute of Scientific and Technical Information of China (English)
TAO Ran; ZHANG Feng; WANG Yue
2008-01-01
As the fractional Fourier transform has attracted a considerable amount of atten-tion in the area of optics and signal processing,the discretization of the fractional Fourier transform becomes vital for the application of the fractional Fourier trans-form.Since the discretization of the fractional Fourier transform cannot be obtained by directly sampling in time domain and the fractional Fourier domain,the discre-tization of the fractional Fourier transform has been investigated recently.A sum-mary of discretizations of the fractional Fourier transform developed in the last nearly two decades is presented in this paper.The discretizations include sampling in the fractional Fourier domain,discrete-time fractional Fourier transform,frac-tional Fourier series,discrete fractional Fourier transform (including 3 main types:linear combination-type;sampling-type;and eigen decomposition-type),and other discrete fractional signal transform.It is hoped to offer a doorstep for the readers who are interested in the fractional Fourier transform.
Fourier Transforms Simplified: Computing an Infrared Spectrum from an Interferogram
Hanley, Quentin S.
2012-01-01
Fourier transforms are used widely in chemistry and allied sciences. Examples include infrared, nuclear magnetic resonance, and mass spectroscopies. A thorough understanding of Fourier methods assists the understanding of microscopy, X-ray diffraction, and diffraction gratings. The theory of Fourier transforms has been presented in this "Journal",…
Some Applications of Fourier's Great Discovery for Beginners
Kraftmakher, Yaakov
2012-01-01
Nearly two centuries ago, Fourier discovered that any periodic function of period T can be presented as a sum of sine waveforms of frequencies equal to an integer times the fundamental frequency [omega] = 2[pi]/T (Fourier's series). It is impossible to overestimate the importance of Fourier's discovery, and all physics or engineering students…
A COMPARISION BETWEEN WALSHHADAMARD AND FOURIER ANALYSIS OF THE EEG SIGNALS
Directory of Open Access Journals (Sweden)
AZADEH BASTANI
2011-07-01
Full Text Available Electroencephalography (EEG is one of the most important diagnostic tools in neurology and getting information about the brain activity. One of this is real-time and quantified study of brain activities to measure the stage of unconsciousness due to injection drug in operation room. EEG signal is a stochastic non-stationary process. Regarding the complexity of brain activities on EEG process, studies are based on time-frequency features analysis of EEG signals. Most of these analyses are based on Fourier Transform and the most significant are classic and parametric estimation of power spectral density analysis. Considering the origins of EEG in the brain, it seems that Walsh-Hadamard transform is more effective than Fourier transform in feature extracting of these signals. In this paper the efficiency of Walsh-Hadamard transform features were comparedwith extracted features from Fourier transform. To evaluate these features, three different classifying algorithms are used. The results showed that Walsh-Hadamard extracted features are suitable tools for recognition of difference between different stages of EEG signals. Simplicity and speed of Walsh-Hadamard transform calculation made it preferable then Fourier spectral features. The fast Walsh-Hadamard transform is an attractive alternative to the fast fourier transform because it is computationally more efficient, and thus faster to perform on a digital computer.
Adaptive Fourier Decomposition Based Time-Frequency Analysis
Institute of Scientific and Technical Information of China (English)
Li-Ming Zhang
2014-01-01
The attempt to represent a signal simultaneously in time and frequency domains is full of challenges. The recently proposed adaptive Fourier decomposition (AFD) offers a practical approach to solve this problem. This paper presents the principles of the AFD based time-frequency analysis in three aspects: instantaneous frequency analysis, frequency spectrum analysis, and the spectrogram analysis. An experiment is conducted and compared with the Fourier transform in convergence rate and short-time Fourier transform in time-frequency distribution. The proposed approach performs better than both the Fourier transform and short-time Fourier transform.
Efficient Scheme for Optimizing Quantum Fourier Circuits
Institute of Scientific and Technical Information of China (English)
JIANG Min; ZHANG Zengke; Tzyh-Jong Tarn
2008-01-01
In quantum circuits, importing of additional qubits can reduce the operation time and prevent de-coherence induced by the environment. However, excessive qubits may make the quantum system vulner-able. This paper describes how to relax existing qubits without additional qubits to significantly reduce the operation time of the quantum Fourier circuit compared to a circuit without optimization. The results indicate that this scheme makes full use of the qubits relaxation. The concepts can be applied to improve similar quantum circuits and guide the physical implementations of quantum algorithms or devices.
Optical Planar Discrete Fourier and Wavelet Transforms
Cincotti, Gabriella; Moreolo, Michela Svaluto; Neri, Alessandro
2007-10-01
We present all-optical architectures to perform discrete wavelet transform (DWT), wavelet packet (WP) decomposition and discrete Fourier transform (DFT) using planar lightwave circuits (PLC) technology. Any compact-support wavelet filter can be implemented as an optical planar two-port lattice-form device, and different subband filtering schemes are possible to denoise, or multiplex optical signals. We consider both parallel and serial input cases. We design a multiport decoder/decoder that is able to generate/process optical codes simultaneously and a flexible logarithmic wavelength multiplexer, with flat top profile and reduced crosstalk.
Los tres teoremas: Fourier - Nyquist - Shannon
Semeria, Marcelo
2015-01-01
Las telecomunicaciones se basan firmemente en un conjunto de teoremas fundamentales. Teorema de Fourier, que permite tratar cualquier forma de onda como si fuese una sumatoria de ondas senos y cosenos. Teorema de muestreo de Nyquist, mediante el cual un único canal puede llevar más de una señal. Teorema de Shannon, con el que se relaciona el ruido de un canal y su ancho de banda con la máxima capacidad teórica del canal empleado. A partir de los toremas nombrados y del conocimiento de los par...
Energy Technology Data Exchange (ETDEWEB)
McMillan, M.; Frelinger, J.A.; Jones, P.P.; Murphy, D.B.; McDevitt, H.O.; Hood, L.
1981-04-01
We demonstrate that an invariant polypeptide, first described by Jones et al. (21), co-immunoprecipitates with our Ia molecules, that its interaction with Ia polypeptides varies with haplotype, and that it is not a precursor of the Aalpha, Abeta, Ealpha, or Ebeta. polypeptides. We also show that the polypeptides that we have previously characterized are contaminated with very little, if any, invariant protein. Further, we have used our high-pressure liquid chromatography tryptic peptide map technique to formally map the genes encoding Aalpha, Abeta, and Ebeta to the I-A subregion using recombinant and F1 hybrid mice.
Initial Results from the USNO Dispersed Fourier Transform Spectrograph
Hajian, A R; Cenko, A T; Olling, R P; Mozurkewich, D; Armstrong, J T; Pohl, B; Petrossian, S; Knuth, K H; Hindsley, R B; Murison, M; Efroimsky, M; Dantowitz, R; Kozubal, M; Currie, D G; Nordgren, T E; Tycner, C; McMillan, R S; Hajian, Arsen R.; Behr, Bradford B.; Cenko, Andrew T.; Olling, Robert P.; Mozurkewich, David; Pohl, Brian; Petrossian, Sevan; Knuth, Kevin H.; Hindsley, Robert B.; Murison, Marc; Efroimsky, Michael; Dantowitz, Ronald; Kozubal, Marek; Currie, Douglas G.; Nordgren, Tyler E.; Tycner, Christopher; Millan, Robert S. Mc
2006-01-01
We have designed and constructed a ``dispersed Fourier Transform Spectrometer'' (dFTS), consisting of a conventional FTS followed by a grating spectrometer. By combining these two devices, we negate a substantial fraction of the sensitivity disadvantage of a conventional FTS for high resolution, broadband, optical spectroscopy, while preserving many of the advantages inherent to interferometric spectrometers. In addition, we have implemented a simple and inexpensive laser metrology system, which enables very precise calibration of the interferometer wavelength scale. The fusion of interferometric and dispersive technologies with a laser metrology system yields an instrument well-suited to stellar spectroscopy, velocimetry, and extrasolar planet detection, which is competitive with existing high-resolution, high accuracy stellar spectrometers. In this paper, we describe the design of our prototype dFTS, explain the algorithm we use to efficiently reconstruct a broadband spectrum from a sequence of narrowband i...
Automatic differentiation for Fourier series and the radii polynomial approach
Lessard, Jean-Philippe; Mireles James, J. D.; Ransford, Julian
2016-11-01
In this work we develop a computer-assisted technique for proving existence of periodic solutions of nonlinear differential equations with non-polynomial nonlinearities. We exploit ideas from the theory of automatic differentiation in order to formulate an augmented polynomial system. We compute a numerical Fourier expansion of the periodic orbit for the augmented system, and prove the existence of a true solution nearby using an a-posteriori validation scheme (the radii polynomial approach). The problems considered here are given in terms of locally analytic vector fields (i.e. the field is analytic in a neighborhood of the periodic orbit) hence the computer-assisted proofs are formulated in a Banach space of sequences satisfying a geometric decay condition. In order to illustrate the use and utility of these ideas we implement a number of computer-assisted existence proofs for periodic orbits of the Planar Circular Restricted Three-Body Problem (PCRTBP).
Some Topics in Fourier Analysis and Approximation Theory
Trigub, R M
1996-01-01
This manuscript presents shortly the results obtained by participants of the scientific seminar which is held more than twenty years under leadership of the author at Donetsk University. In the list of references main publications are given. These results are published in serious scientific journals and reported at various conferences, including international ones at Moscow,ICM66; Kaluga,1975; Kiev,1983; Haifa,1994; Zürich,ICM94; Moscow,1995. The area of investigation is the Fourier analysis and the theory of approximation of functions. Used are methods of classical analysis including special functions, Banach spaces, etc., of harmonic analysis in finitedimensional Euclidean space, of Diophantine analysis, of random choice, etc. The results due to the author and active participants of the seminar, namely E. S. Belinskii, O. I. Kuznetsova, E. R. Liflyand, Yu. L. Nosenko, V. A. Glukhov, V. P. Zastavny, Val. V. Volchkov, V. O. Leontyev, and others, are given. Besides the participants of the seminar and other ma...
Fourier transform for fermionic systems and the spectral tensor network.
Ferris, Andrew J
2014-07-01
Leveraging the decomposability of the fast Fourier transform, I propose a new class of tensor network that is efficiently contractible and able to represent many-body systems with local entanglement that is greater than the area law. Translationally invariant systems of free fermions in arbitrary dimensions as well as 1D systems solved by the Jordan-Wigner transformation are shown to be exactly represented in this class. Further, it is proposed that these tensor networks be used as generic structures to variationally describe more complicated systems, such as interacting fermions. This class shares some similarities with the Evenbly-Vidal branching multiscale entanglement renormalization ansatz, but with some important differences and greatly reduced computational demands.
Energy Technology Data Exchange (ETDEWEB)
Etard, C.; Aubert, B. [IRSN, Unite d' Expertise en Radioprotection Medicale, DRPH/SER/UEM, 92 - Fontenay-aux-Roses (France)
2009-10-15
After a medical exposure of a pregnant patient, the practitioner can seek I.R.S.N. to estimate the foetal dose. From 2004 to 2008, 326 foetal doses have been estimated by I.R.S.N. following radiological or nuclear medicine examinations, among them 246 corresponded to situations where uterus was directly exposed. These estimations were performed by calculations based on the technical parameters of the exam. In conventional radiology, foetal doses estimated are lower than 35 mGy and their averages are in agreement with international data. In computed tomography, doses are generally in the range 15 to 65 mGy, but can exceed 100 mGy in certain configurations. In this field, practitioners must pay a particular attention to the optimization of pelvic exams of female patients and estimate individually the foetal dose in case of pregnancy. Furthermore, the dispersal of doses for the same type of radiological exam shows heterogeneous practices, sometimes very far from the recommendations of the French society of radiology. In nuclear medicine, foetal doses estimated are lower than 10 mGy, without taking into account the dose due to a possible associated CT examination. (authors)
DEFF Research Database (Denmark)
Thorlacius, Lisbeth
2009-01-01
planlægning af de funktionelle og indholdsmæssige aspekter ved websites. Der findes en stor mængde teori- og metodebøger, som har specialiseret sig i de tekniske problemstillinger i forbindelse med interaktion og navigation, samt det sproglige indhold på websites. Den danske HCI (Human Computer Interaction...... hyperfunktionelle websites. Det primære ærinde for HCI-eksperterne er at udarbejde websites, som er brugervenlige. Ifølge deres direktiver skal websites være opbygget med hurtige og effektive navigations- og interaktionsstrukturer, hvor brugeren kan få sine informationer ubesværet af lange downloadingshastigheder...... eller blindgyder, når han/hun besøger sitet. Studier i design og analyse af de visuelle og æstetiske aspekter i planlægning og brug af websites har imidlertid kun i et begrænset omfang været under reflektorisk behandling. Det er baggrunden for dette kapitel, som indleder med en gennemgang af æstetikkens...
The Fourier transform of tubular densities
Prior, C B
2012-05-18
We consider the Fourier transform of tubular volume densities, with arbitrary axial geometry and (possibly) twisted internal structure. This density can be used to represent, among others, magnetic flux or the electron density of biopolymer molecules. We consider tubes of both finite radii and unrestricted radius. When there is overlap of the tube structure the net density is calculated using the super-position principle. The Fourier transform of this density is composed of two expressions, one for which the radius of the tube is less than the curvature of the axis and one for which the radius is greater (which must have density overlap). This expression can accommodate an asymmetric density distribution and a tube structure which has non-uniform twisting. In addition we give several simpler expressions for isotropic densities, densities of finite radius, densities which decay at a rate sufficient to minimize local overlap and finally individual surfaces of the tube manifold. These simplified cases can often be expressed as arclength integrals and can be evaluated using a system of first-order ODEs. © 2012 IOP Publishing Ltd.
Fourier transform inequalities for phylogenetic trees.
Matsen, Frederick A
2009-01-01
Phylogenetic invariants are not the only constraints on site-pattern frequency vectors for phylogenetic trees. A mutation matrix, by its definition, is the exponential of a matrix with non-negative off-diagonal entries; this positivity requirement implies non-trivial constraints on the site-pattern frequency vectors. We call these additional constraints "edge-parameter inequalities". In this paper, we first motivate the edge-parameter inequalities by considering a pathological site-pattern frequency vector corresponding to a quartet tree with a negative internal edge. This site-pattern frequency vector nevertheless satisfies all of the constraints described up to now in the literature. We next describe two complete sets of edge-parameter inequalities for the group-based models; these constraints are square-free monomial inequalities in the Fourier transformed coordinates. These inequalities, along with the phylogenetic invariants, form a complete description of the set of site-pattern frequency vectors corresponding to bona fide trees. Said in mathematical language, this paper explicitly presents two finite lists of inequalities in Fourier coordinates of the form "monomial < or = 1", each list characterizing the phylogenetically relevant semialgebraic subsets of the phylogenetic varieties.
Fourier coefficient description of left ventricular shape.
Round, W H; Bates, R H; Ikram, H
1991-12-01
A method of quantifying the shape of the left ventricle of the heart as seen in 2D echocardiograms was developed. It is based on describing the shape in terms of the coefficients a fifth-order trigonometric Fourier series. Such a series has eleven Fourier coefficients which is too large a number for clinical application so pairs of coefficients are combined to give six coefficients (alpha 0, alpha 1, ... , alpha 5). A trial was conducted to test the ability of the coefficient description to classify subjects as having normal right ventricles or ventricles with an apical abnormality. The tests showed that one of the coefficients (alpha 2) was higher for the subjects with an apical abnormality and that this difference increased with exercise. This is as was expected. However, it was found to be difficult to get a reliable estimate of alpha 2 from a single scan of a patient and that it is therefore probably necessary to average data from several scans to obtain a reliable alpha 2 value for a single patient.
Efficient single pixel imaging in Fourier space
Bian, Liheng; Suo, Jinli; Hu, Xuemei; Chen, Feng; Dai, Qionghai
2016-08-01
Single pixel imaging (SPI) is a novel technique capturing 2D images using a bucket detector with a high signal-to-noise ratio, wide spectrum range and low cost. Conventional SPI projects random illumination patterns to randomly and uniformly sample the entire scene’s information. Determined by Nyquist sampling theory, SPI needs either numerous projections or high computation cost to reconstruct the target scene, especially for high-resolution cases. To address this issue, we propose an efficient single pixel imaging technique (eSPI), which instead projects sinusoidal patterns for importance sampling of the target scene’s spatial spectrum in Fourier space. Specifically, utilizing the centrosymmetric conjugation and sparsity priors of natural images’ spatial spectra, eSPI sequentially projects two \\tfrac{π }{2}-phase-shifted sinusoidal patterns to obtain each Fourier coefficient in the most informative spatial frequency bands. eSPI can reduce requisite patterns by two orders of magnitude compared to conventional SPI, which helps a lot for fast and high-resolution SPI.
Uniformity of measures with Fourier frames
Dutkay, Dorin Ervin
2012-01-01
We examine Fourier frames and, more generally, frame measures for different probability measures. We prove that if a measure has an associated frame measure, then it must have a certain uniformity in the sense that the weight is distributed quite uniformly on its support. To be more precise, by considering certain absolute continuity properties of the measure and its translation, we recover the characterization on absolutely continuous measures $g\\, dx$ with Fourier frames obtained in \\cite{Lai11}. Moreover, we prove that the frame bounds are pushed away by the essential infimum and supremum of the function $g$. This also shows that absolutely continuous spectral measures supported on a set $\\Omega$, if they exist, must be the standard Lebesgue measure on $\\Omega$ up to a multiplicative constant. We then investigate affine iterated function systems (IFSs), we show that if an IFS with no overlap admits a frame measure then the probability weights are all equal. Moreover, we also show that the {\\L}aba-Wang conj...
Vélez-Rábago, Rodrigo; Solorza-Calderón, Selene; Jordan-Aramburo, Adina
2016-12-01
This work presents an image pattern recognition system invariant to translation, scale and rotation. The system uses the Fourier transform to achieve the invariance to translation and the analytical Forier-Mellin transform for the invariance to scale and rotation. According with the statistical theory of box-plots, the pattern recognition system has a confidence level at least of 95.4%.
Energy Technology Data Exchange (ETDEWEB)
Bartosch, T. [Erlanger-Nuernberg Univ., Erlanger (Germany). Lehrstul fuer Nachrichtentechnik I; Seidl, D. [Seismologisches Zentralobservatorium Graefenberg, Erlanegen (Greece). Bundesanstalt fuer Geiwissenschaften und Rohstoffe
1999-06-01
Among a variety of spectrogram methods short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were selected to analyse transients in non-stationary signals. Depending on the properties of the tremor signals from the volcanos Mt. Stromboli, Mt. Semeru and Mt. Pinatubo were analyzed using both methods. The CWT can also be used to extend the definition of coherency into a time-varying coherency spectrogram. An example is given using array data from the volcano Mt. Stromboli (Italy).
Statistical properties of Fourier-based time-lag estimates
Epitropakis, A
2016-01-01
Context: The study of X-ray time-lag spectra in AGN is currently an active research area, as it has the potential to illuminate the physics and geometry of the innermost region (i.e. close to the putative super-massive black hole) in these objects. In order to obtain reliable information from these studies, the statistical properties of time-lags estimated from data must be known as accurately as possible. Aims: We investigated the statistical properties of Fourier-based time-lag estimates (i.e. based on the cross-periodogram), using evenly sampled time series with no missing points. Our aim is to provide practical "guidelines" on estimating time-lags which are minimally biased (i.e. whose mean is close to their intrinsic value) and have known errors. Methods: Our investigation is based on both analytical work and extensive numerical simulations. The latter consisted of generating artificial time series with various signal-to-noise ratios and sampling patterns/durations similar to those offered by AGN observa...
A Comparative Performance Analyses of FFT Based OFDM and DWT Based OFDM Systems
Oksuz, Engin; Altun, Ahmet; Ulgerli, Busra; Yucel, Gokay; Ozen, Ali
2016-01-01
While continuously increasing demand for high data rates, to develop more efficient wireless communication systems will always be needed. Orthogonal Frequency Division Multiplexing (OFDM) is a promising multi-carrier wireless communication system for high-speed data transmission with spectral efficiency and fading immunity. Conventional OFDM systems use Fourier filters with the help of the inverse Fast Fourier Transform (IFFT) and Fast Fourier Transform (FFT) for modulation and demodulation i...
Fourier transforms in generalized Fock spaces
Directory of Open Access Journals (Sweden)
John Schmeelk
1990-01-01
Full Text Available A classical Fock space consists of functions of the form,Φ↔(ϕ0,ϕ1,…,ϕq,…,where ϕ0∈C and ϕq∈L2(R3q, q≥1. We will replace the ϕq, q≥1 with q-symmetric rapid descent test functions within tempered distribution theory. This space is a natural generalization of a classical Fock space as seen by expanding functionals having generalized Taylor series. The particular coefficients of such series are multilinear functionals having tempered distributions as their domain. The Fourier transform will be introduced into this setting. A theorem will be proven relating the convergence of the transform to the parameter, s, which sweeps out a scale of generalized Fock spaces.
Lacunary Fourier Series for Compact Quantum Groups
Wang, Simeng
2016-05-01
This paper is devoted to the study of Sidon sets, {Λ(p)} -sets and some related notions for compact quantum groups. We establish several different characterizations of Sidon sets, and in particular prove that any Sidon set in a discrete group is a strong Sidon set in the sense of Picardello. We give several relations between Sidon sets, {Λ(p)} -sets and lacunarities for L p -Fourier multipliers, generalizing a previous work by Blendek and Michalic̆ek. We also prove the existence of {Λ(p)} -sets for orthogonal systems in noncommutative L p -spaces, and deduce the corresponding properties for compact quantum groups. Central Sidon sets are also discussed, and it turns out that the compact quantum groups with the same fusion rules and the same dimension functions have identical central Sidon sets. Several examples are also included.
Multicomplementary operators via finite Fourier transform
Energy Technology Data Exchange (ETDEWEB)
Klimov, Andrei B [Departamento de Fisica, Universidad de Guadalajara, Revolucion 1500, 44420 Guadalajara, Jalisco (Mexico); Sanchez-Soto, Luis L [Department of Physics, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Guise, Hubert de [Department of Physics, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada)
2005-03-25
A complete set of d + 1 mutually unbiased bases exists in a Hilbert space of dimension d, whenever d is a power of a prime. We discuss a simple construction of d + 1 disjoint classes (each one having d - 1 commuting operators) such that the corresponding eigenstates form sets of unbiased bases. Such a construction works properly for prime dimension. We investigate an alternative construction in which the real numbers that label the classes are replaced by a finite field having d elements. One of these classes is diagonal, and can be mapped to cyclic operators by means of the finite Fourier transform, which allows one to understand complementarity in a similar way as for the position-momentum pair in standard quantum mechanics. The relevant examples of two and three qubits and two qutrits are discussed in detail.
Fourier transform spectroscopy for future planetary missions
Brasunas, John; Kolasinski, John; Kostiuk, Ted; Hewagama, Tilak
2017-01-01
Thermal-emission infrared spectroscopy is a powerful tool for exploring the composition, temperature structure, and dynamics of planetary atmospheres; and the temperature of solid surfaces. A host of Fourier transform spectrometers (FTS) such as Mariner IRIS, Voyager IRIS, and Cassini CIRS from NASA Goddard have made and continue to make important new discoveries throughout the solar system. Future FTS instruments will have to be more sensitive (when we concentrate on the colder, outer reaches of the solar system), and less massive and less power-hungry as we cope with decreasing resource allotments for future planetary science instruments. With this in mind, we have developed CIRS-lite, a smaller version of the CIRS FTS for future planetary missions. We discuss the roadmap for making CIRS-lite a viable candidate for future planetary missions, including the recent increased emphasis on ocean worlds (Europa, Encelatus, Titan) and also on smaller payloads such as CubeSats and SmallSats.
Model of computation for Fourier optical processors
Naughton, Thomas J.
2000-05-01
We present a novel and simple theoretical model of computation that captures what we believe are the most important characteristics of an optical Fourier transform processor. We use this abstract model to reason about the computational properties of the physical systems it describes. We define a grammar for our model's instruction language, and use it to write algorithms for well-known filtering and correlation techniques. We also suggest suitable computational complexity measures that could be used to analyze any coherent optical information processing technique, described with the language, for efficiency. Our choice of instruction language allows us to argue that algorithms describable with this model should have optical implementations that do not require a digital electronic computer to act as a master unit. Through simulation of a well known model of computation from computer theory we investigate the general-purpose capabilities of analog optical processors.
Fourier optics of image formation in LEEM
Energy Technology Data Exchange (ETDEWEB)
Pang, A B; Altman, M S [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Mueller, Th; Bauer, Ernst [Physikalisches Institute, Technische Universitaet Clausthal, Leibnizstrasse 4, D-38678 Clausthal-Zellerfeld (Germany)
2009-08-05
A Fourier optics calculation of image formation in low energy electron microscopy (LEEM) is presented. The adaptation of the existing theory for transmission electron microscopy to the treatment of LEEM and other forms of cathode lens electron microscopy is explained. The calculation incorporates imaging errors that are caused by the objective lens (aberrations), contrast aperture (diffraction), imperfect source characteristics, and voltage and current instabilities. It is used to evaluate the appearance of image features that arise from phase objects such as surface steps and amplitude objects that produce what is alternatively called amplitude, reflectivity or diffraction contrast in LEEM. This formalism can be used after appropriate modification to treat image formation in other emission microscopies. Implications for image formation in the latest aberration-corrected instruments are also discussed.
Two-dimensional fourier transform spectrometer
Energy Technology Data Exchange (ETDEWEB)
DeFlores, Lauren; Tokmakoff, Andrei
2016-10-25
The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.
Efficient Two-Comb Fourier Spectroscopy
Mandon, Julien; Picqué, Nathalie
2008-01-01
Molecular fingerprinting through absorption spectroscopy is a powerful analytical method. Wide spectral ranges are explored with Doppler-limited resolution. Fast data acquisition, accurate measurements of frequency, intensity, and line shape; time-resolved, selective spectra are achieved with excellent sensitivities. However, presently spectrometers are unable to provide all these features at once. Here we show that, based on frequency comb lasers, a spectrometer may overcome this difficulty. We have recorded two series of spectra with a 1.5 $\\mu$m Cr:YAG frequency comb. In the first series, we propose to use the comb structure to considerably improve the recording time and signal to noise ratio of Doppler-resolved spectra, (Fourier Transform (FT) of the beating signatures of two combs issued from the same initial laser). The second series demonstrates that under very simple experimental conditions, FT spectroscopists may record much more sensitive spectra than with the usual incoherent white light source. We...
Two-dimensional fourier transform spectrometer
DeFlores, Lauren; Tokmakoff, Andrei
2013-09-03
The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.
Wavelets for approximate Fourier transform and data compression
Guo, Haitao
This dissertation has two parts. In the first part, we develop a wavelet-based fast approximate Fourier transform algorithm. The second part is devoted to the developments of several wavelet-based data compression techniques for image and seismic data. We propose an algorithm that uses the discrete wavelet transform (DWT) as a tool to compute the discrete Fourier transform (DFT). The classical Cooley-Tukey FFT is shown to be a special case of the proposed algorithm when the wavelets in use are trivial. The main advantage of our algorithm is that the good time and frequency localization of wavelets can be exploited to approximate the Fourier transform for many classes of signals, resulting in much less computation. Thus the new algorithm provides an efficient complexity versus accuracy tradeoff. When approximations are allowed, under certain sparsity conditions, the algorithm can achieve linear complexity, i.e. O(N). The proposed algorithm also has built-in noise reduction capability. For waveform and image compression, we propose a novel scheme using the recently developed Burrows-Wheeler transform (BWT). We show that the discrete wavelet transform (DWT) should be used before the Burrows-Wheeler transform to improve the compression performance for many natural signals and images. We demonstrate that the simple concatenation of the DWT and BWT coding performs comparably as the embedded zerotree wavelet (EZW) compression for images. Various techniques that significantly improve the performance of our compression scheme are also discussed. The phase information is crucial for seismic data processing. However, traditional compression schemes do not pay special attention to preserving the phase of the seismic data, resulting in the loss of critical information. We propose a lossy compression method that preserves the phase as much as possible. The method is based on the self-adjusting wavelet transform that adapts to the locations of the significant signal components
Note on Redshift Distortion in Fourier Space
Institute of Scientific and Technical Information of China (English)
Yan-Chuan Cai; Jun Pan
2007-01-01
We explore features of redshift distortion in Fourier analysis of N-body simulations.The phases of the Fourier modes of dark matter density fluctuation are generally shifted by the peculiar motion along the line of sight, the induced phase shift is stochastic and has a probability distribution function (PDF) that is symmetric about the peak at zero shift and whose exact shape depends on the wave vector, except on very large scales where phases are invariant by linear perturbation theory. Analysis of the phase shifts motivates our phenomenological models for the bispectrum in redshift space. Comparison with simulations shows that our toy models are very successful in modeling bispectrum of equilateral and isosceles triangles at large scales. In the second part we compare the monopole of the power spectrum and bispectrum in the radial and plane-parallel distortion to test the plane-parallel approximation.We confirm the results of Scoccimarro that difference of power spectrum is at the level of 10%, and, in the reduced bispectrum, the difference is as small as a few percent. However, on the plane perpendicular to the line of sight of kz = 0, the difference in power spectrum between the radial and plane-parallel approximation can be more than ～ 10%, and even worse on very small scales. Such difference is prominent for bispectrum, especially for configurations of tilted triangles. Non-Gaussian signals under the radial distortion on small scales are systematically biased downside than are in the plane-parallel approximation, with amplitudes depending on the opening angle of the sample point to the observer. This observation gives warning to the practice of using the power spectrum and bispectrum measured on the kz = 0 plane as estimates of the real space statistics.
Band-structural and Fourier-spectral properties of one-dimensional generalized Fibonacci lattices
Oh, G. Y.; Lee, M. H.
1993-11-01
We study the electronic and Fourier-spectral properties of one-dimensional generalized Fibonacci lattices generated by the stacking rule Sl+1=SnlSml-1 with positive integers n and m, where Sl is the lth generational binary sequence. After showing that, in the limit of the large potential strength, the energy spectrum of a lattice with certain specific n and m can be determined by the associated characteristic value τ(n,m), we investigate the relation between the electronic band structure and the Fourier spectrum. When the lattice possesses the Pisot-Vijayaraghavan (PV) property (i.e., when n+1>m), the Fourier spectrum is closely related to the electronic band structure; the location and the relative strength of the Fourier spectral peak is in agreement with the location and the relative width of the energy spectral gap. On the other hand, when the lattice possesses no PV property (i.e., when n+1nature of the lattice becomes clearer with the increase of p.
Applying Quaternion Fourier Transforms for Enhancing Color Images
Directory of Open Access Journals (Sweden)
M.I. Khalil
2012-03-01
Full Text Available The Fourier transforms play a critical role in a broad range of image processing applications, including enhancement, analysis, restoration, and compression. Until recently, it was common to use the conventional methods to deal with colored images. These methods are based on RGB decomposition of the colored image by separating it into three separate scalar images and computing the Fourier transforms of these images separately. The computing of the Hypercomplex 2D Fourier transform of a color image as a whole unit has only recently been realized. This paper is concerned with frequency domain noise reduction of color images using quaternion Fourier transforms. The approach is based on obtaining quaternion Fourier transform of the color image and applying the Gaussian filter to it in the frequency domain. The filtered image is then obtained by calculating the inverse quaternion Fourier transforms.
Generalized Fourier analysis for phase retrieval of fringe pattern.
Zhong, Jingang; Weng, Jiawen
2010-12-20
A generalized Fourier analysis, by use of an adaptive multiscale windowed Fourier transform (AWFT), has been presented for the phase retrieval of fringe patterns. The Fourier transform method can be considered as a special case of AWFT method with a maximum window. The instantaneous frequency of the local signal is introduced to estimate whether the condition for separating the first spectrum component is satisfied for the phase retrieval of fringe patterns. The adaptive window width for this algorithm is determined by the length of the local stationary fringe pattern in order to balance the frequency and space resolution. The local stationary length of fringe pattern is defined as the signal satisfying the condition that whose first spectrum component is separated from all the other spectra within the local spatial area. In comparison with Fourier transform, fixed windowed Fourier transform and wavelet transform in numerical simulation and experiment, the adaptive multiscale windowed Fourier transform can present more accurate results of phase retrieval.
α-bandlimited diffuser in fractional Fourier optics
Patiño-Vanegas, Alberto; Durand, Pierre-Emmanuel; Torres, Rafael; Pellat-Finet, Pierre
2016-04-01
We propose a method for calculating appropriate α-band limited diffusers using the fractional Fourier transform. In order to do this, we implement a method for performing a numerical interpolation in the fractional Fourier domain. Such diffusers with compact support in the Fresnel regime may be used in fractional Fourier optical systems where the use of diffusers produce speckles, e.g. digital holography or optical encryption. Numerical simulations are presented.
Refinement of Fourier Coefficients from the Stokes Deconvoluted Profile
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Computer-aided experimental technique was used to study the Stokes deconvolution of X-ray diffraction profile.Considerable difference can be found between the Fourier coefficients obtained from the deconvolutions of singlet and doublet experimental profiles. Nevertheless, the resultant physical profiles corresponding to singlet and doublet profiles are identical. An approach is proposed to refine the Fourier coefficients, and the refined Fourier coefficients coincide well with that obtained from the deconvolution of singlet experimental profile.
A Note on Fourier and the Greenhouse Effect
Postma, Joseph E
2015-01-01
Joseph Fourier's discovery of the greenhouse effect is discussed and is compared to the modern conception of the greenhouse effect. It is confirmed that what Fourier discovered is analogous to the modern concept of the greenhouse effect. However, the modern concept of the greenhouse effect is found to be based on a paradoxical analogy to Fourier's greenhouse work and so either Fourier's greenhouse work, the modern conception of the greenhouse effect, or the modern definition of heat is incorrect. The solution to this problem is not feigned to be given here.
Generalized Fourier slice theorem for cone-beam image reconstruction.
Zhao, Shuang-Ren; Jiang, Dazong; Yang, Kevin; Yang, Kang
2015-01-01
The cone-beam reconstruction theory has been proposed by Kirillov in 1961, Tuy in 1983, Feldkamp in 1984, Smith in 1985, Pierre Grangeat in 1990. The Fourier slice theorem is proposed by Bracewell 1956, which leads to the Fourier image reconstruction method for parallel-beam geometry. The Fourier slice theorem is extended to fan-beam geometry by Zhao in 1993 and 1995. By combining the above mentioned cone-beam image reconstruction theory and the above mentioned Fourier slice theory of fan-beam geometry, the Fourier slice theorem in cone-beam geometry is proposed by Zhao 1995 in short conference publication. This article offers the details of the derivation and implementation of this Fourier slice theorem for cone-beam geometry. Especially the problem of the reconstruction from Fourier domain has been overcome, which is that the value of in the origin of Fourier space is 0/0. The 0/0 type of limit is proper handled. As examples, the implementation results for the single circle and two perpendicular circle source orbits are shown. In the cone-beam reconstruction if a interpolation process is considered, the number of the calculations for the generalized Fourier slice theorem algorithm is O(N^4), which is close to the filtered back-projection method, here N is the image size of 1-dimension. However the interpolation process can be avoid, in that case the number of the calculations is O(N5).
Efficient Option Pricing Methods Based on Fourier Series Expansions
Institute of Scientific and Technical Information of China (English)
Deng DING; Sio Chong U
2011-01-01
A novel option pricing method based on Fourier-cosine series expansion was proposed by Fang and Oosterlee. Developing their idea, three new option pricing methods based on Fourier, Fourier-cosine and Fourier-sine series expansions are presented in this paper, which are more efficient when the option prices are calculated with many strike prices. A series of numerical experiments under different exp-Lévy models are also given to compare these new methods with the Fang and Oosterlee's method and other methods.
On a General Class of Trigonometric Functions and Fourier Series
Pavao, H. Germano; Capelas de Oliveira, E.
2008-01-01
We discuss a general class of trigonometric functions whose corresponding Fourier series can be used to calculate several interesting numerical series. Particular cases are presented. (Contains 4 notes.)
Prum, R. O.; Torres, R.; Williamson, S.; Dyck, J.
1999-01-01
We conducted two-dimensional (2D) discrete Fourier analyses of the spatial variation in refractive index of the spongy medullary keratin from four different colours of structurally coloured feather barbs from three species of bird: the rose-faced lovebird, Agapornis roseicollis (Psittacidae), the budgerigar, Melopsittacus undulatus (Psittacidae), and the Gouldian finch, Poephila guttata (Estrildidae). These results indicate that the spongy medullary keratin is a nanostructured tissue that functions as an array of coherent scatterers. The nanostructure of the medullary keratin is nearly uniform in all directions. The largest Fourier components of spatial variation in refractive index in the tissue are of the appropriate size to produce the observed colours by constructive interference alone. The peaks of the predicted reflectance spectra calculated from the 2D Fourier power spectra are congruent with the reflectance spectra measured by using microspectrophotometry. The alternative physical models for the production of these colours, the Rayleigh and Mie theories, hypothesize that medullary keratin is an incoherent array and that scattered waves are independent in phase. This assumption is falsified by the ring-like Fourier power spectra of these feathers, and the spacing of the scattering air vacuoles in the medullary keratin. Structural colours of avian feather barbs are produced by constructive interference of coherently scattered light waves from the optically heterogeneous matrix of keratin and air in the spongy medullary layer.
Zhang, Fang; Zhu, Jing; Song, Qiang; Yue, Weirui; Liu, Jingdan; Wang, Jian; Situ, Guohai; Huang, Huijie
2015-10-20
In general, Fourier transform lenses are considered as ideal in the design algorithms of diffractive optical elements (DOEs). However, the inherent aberrations of a real Fourier transform lens disturb the far field pattern. The difference between the generated pattern and the expected design will impact the system performance. Therefore, a method for modifying the Fourier spectrum of DOEs without introducing other optical elements to reduce the aberration effect of the Fourier transform lens is proposed. By applying this method, beam shaping performance is improved markedly for the optical system with a real Fourier transform lens. The experiments carried out with a commercial Fourier transform lens give evidence for this method. The method is capable of reducing the system complexity as well as improving its performance.
Fan beam image reconstruction with generalized Fourier slice theorem.
Zhao, Shuangren; Yang, Kang; Yang, Kevin
2014-01-01
For parallel beam geometry the Fourier reconstruction works via the Fourier slice theorem (or central slice theorem, projection slice theorem). For fan beam situation, Fourier slice can be extended to a generalized Fourier slice theorem (GFST) for fan-beam image reconstruction. We have briefly introduced this method in a conference. This paper reintroduces the GFST method for fan beam geometry in details. The GFST method can be described as following: the Fourier plane is filled by adding up the contributions from all fanbeam projections individually; thereby the values in the Fourier plane are directly calculated for Cartesian coordinates such avoiding the interpolation from polar to Cartesian coordinates in the Fourier domain; inverse fast Fourier transform is applied to the image in Fourier plane and leads to a reconstructed image in spacial domain. The reconstructed image is compared between the result of the GFST method and the result from the filtered backprojection (FBP) method. The major differences of the GFST and the FBP methods are: (1) The interpolation process are at different data sets. The interpolation of the GFST method is at projection data. The interpolation of the FBP method is at filtered projection data. (2) The filtering process are done in different places. The filtering process of the GFST is at Fourier domain. The filtering process of the FBP method is the ramp filter which is done at projections. The resolution of ramp filter is variable with different location but the filter in the Fourier domain lead to resolution invariable with location. One advantage of the GFST method over the FBP method is in short scan situation, an exact solution can be obtained with the GFST method, but it can not be obtained with the FBP method. The calculation of both the GFST and the FBP methods are at O(N^3), where N is the number of pixel in one dimension.
Stepwise Iterative Fourier Transform: The SIFT
Benignus, V. A.; Benignus, G.
1975-01-01
A program, designed specifically to study the respective effects of some common data problems on results obtained through stepwise iterative Fourier transformation of synthetic data with known waveform composition, was outlined. Included in this group were the problems of gaps in the data, different time-series lengths, periodic but nonsinusoidal waveforms, and noisy (low signal-to-noise) data. Results on sinusoidal data were also compared with results obtained on narrow band noise with similar characteristics. The findings showed that the analytic procedure under study can reliably reduce data in the nature of (1) sinusoids in noise, (2) asymmetric but periodic waves in noise, and (3) sinusoids in noise with substantial gaps in the data. The program was also able to analyze narrow-band noise well, but with increased interpretational problems. The procedure was shown to be a powerful technique for analysis of periodicities, in comparison with classical spectrum analysis techniques. However, informed use of the stepwise procedure nevertheless requires some background of knowledge concerning characteristics of the biological processes under study.
[X-ray diffraction Fourier fingerprint of mineral Chinese medicine Chloriti Lapis].
Liu, ShengJin; Wu, Dekang; Lin, Ruichao; Liu, Xunhong; Fu, Xingsheng; Kong, Qingyou
2011-09-01
The technology of powder X-ray diffraction (XRD) was used for analysis Chloriti Lapis and the XRD Fourier fingerprints were established. The dates were analyzed by fuzzy cluster and fingerprint similarity evaluation software to compare the similarity of samples. XRD fingerprint with 10 common peaks of 14 batches of Chloriti Lapis were established. The average, median coefficients of crystal lattice spacing d (A), peak position 2 theta, relative intensity value I/I0 (%) were all more than 0.95. And similarity( angle cosine value) were all more than 0. 97. There were small number samples differed from others. And obvious differences between the pre-and post-processing samples. This paper shows the powder XRD Fourier fingerprint can be used for appraisal and study of the Chloriti Lapis.
FOURIER SERIES AND CHEBYSHEV POLYNOMIALS IN STATISTICAL DISTRIBUTION THEORY.
After the elementary functions, the Fourier series are the most important functions in applied mathematics. Nevertheless, they have been somewhat...neglected in statistical distribution theory. In this paper, the reasons for this omission are investigated and certain modifications of the Fourier ... series proposed. These results are presented in the form of representation theorems. In addition to the basic theorems, computational algorithms and
Integrability of the Fourier transform: functions of bounded variation
Liflyand, E
2012-01-01
Certain relations between the Fourier transform of a function of bounded variation and the Hilbert transform of its derivative are revealed. The widest subspaces of the space of functions of bounded variation are indicated in which the cosine and sine Fourier transforms are integrable.
Geometric interpretations of the Discrete Fourier Transform (DFT)
Campbell, C. W.
1984-01-01
One, two, and three dimensional Discrete Fourier Transforms (DFT) and geometric interpretations of their periodicities are presented. These operators are examined for their relationship with the two sided, continuous Fourier transform. Discrete or continuous transforms of real functions have certain symmetry properties. The symmetries are examined for the one, two, and three dimensional cases. Extension to higher dimension is straight forward.
Solving Fractional Partial Differential Equations with Corrected Fourier Series Method
Directory of Open Access Journals (Sweden)
Nor Hafizah Zainal
2014-01-01
Full Text Available The corrected Fourier series (CFS is proposed for solving partial differential equations (PDEs with fractional time derivative on a finite domain. In the previous work, we have been solving partial differential equations by using corrected Fourier series. The fractional derivatives are described in Riemann sense. Some numerical examples are presented to show the solutions.
Realization of quantum discrete Fourier transform with NMR
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The pulse sequences of the logic operations used in quantum discrete Fourier transform are designed for the experiment of nuclear magnetic resonance(NMR), and 2-qubit discrete Fourier transforms are implemented experimentally with NMR. The experimental errors are examined and methods for reducing the errors are proposed.
AN ANOMALY INTRUSION DETECTION METHOD USING FOURIER TRANSFORM
Institute of Scientific and Technical Information of China (English)
Yue Bing; Zhao Yuexia; Xu Zhoujun; Fu Hongjuan; Ma Fengning
2004-01-01
A set of discrete points obtained from audit records on a behavior session is processed with Fourier transform. The criterion of selecting Fourier transform coefficients is introduced, and is used to find a unified value from the set of coefficients. This unified value is compared with a threshold to determine whether the session is abnormal. Finally simple test results are reported.
Fiber Optic Fourier Transform White-Light Interferometry
Institute of Scientific and Technical Information of China (English)
Yi Jiang; Cai-Jie Tang
2008-01-01
Fiber optic Fourier transform white-light inter-fereometry is presented to interrogate the absolute optical path difference of an Mach-Zehnder inter-ferometer. The phase change of the interferometer caused by scanning wavelength can be calculated by a Fourier transform-based phase demodulation technique. A linear output is achieved.
Exploring Fourier Series and Gibbs Phenomenon Using Mathematica
Ghosh, Jonaki B.
2011-01-01
This article describes a laboratory module on Fourier series and Gibbs phenomenon which was undertaken by 32 Year 12 students. It shows how the use of CAS played the role of an "amplifier" by making higher level mathematical concepts accessible to students of year 12. Using Mathematica students were able to visualise Fourier series of…
Correction for Eddy Current-Induced Echo-Shifting Effect in Partial-Fourier Diffusion Tensor Imaging
Directory of Open Access Journals (Sweden)
Trong-Kha Truong
2015-01-01
Full Text Available In most diffusion tensor imaging (DTI studies, images are acquired with either a partial-Fourier or a parallel partial-Fourier echo-planar imaging (EPI sequence, in order to shorten the echo time and increase the signal-to-noise ratio (SNR. However, eddy currents induced by the diffusion-sensitizing gradients can often lead to a shift of the echo in k-space, resulting in three distinct types of artifacts in partial-Fourier DTI. Here, we present an improved DTI acquisition and reconstruction scheme, capable of generating high-quality and high-SNR DTI data without eddy current-induced artifacts. This new scheme consists of three components, respectively, addressing the three distinct types of artifacts. First, a k-space energy-anchored DTI sequence is designed to recover eddy current-induced signal loss (i.e., Type 1 artifact. Second, a multischeme partial-Fourier reconstruction is used to eliminate artificial signal elevation (i.e., Type 2 artifact associated with the conventional partial-Fourier reconstruction. Third, a signal intensity correction is applied to remove artificial signal modulations due to eddy current-induced erroneous T2*-weighting (i.e., Type 3 artifact. These systematic improvements will greatly increase the consistency and accuracy of DTI measurements, expanding the utility of DTI in translational applications where quantitative robustness is much needed.
Truong, Trong-Kha; Song, Allen W; Chen, Nan-Kuei
2015-01-01
In most diffusion tensor imaging (DTI) studies, images are acquired with either a partial-Fourier or a parallel partial-Fourier echo-planar imaging (EPI) sequence, in order to shorten the echo time and increase the signal-to-noise ratio (SNR). However, eddy currents induced by the diffusion-sensitizing gradients can often lead to a shift of the echo in k-space, resulting in three distinct types of artifacts in partial-Fourier DTI. Here, we present an improved DTI acquisition and reconstruction scheme, capable of generating high-quality and high-SNR DTI data without eddy current-induced artifacts. This new scheme consists of three components, respectively, addressing the three distinct types of artifacts. First, a k-space energy-anchored DTI sequence is designed to recover eddy current-induced signal loss (i.e., Type 1 artifact). Second, a multischeme partial-Fourier reconstruction is used to eliminate artificial signal elevation (i.e., Type 2 artifact) associated with the conventional partial-Fourier reconstruction. Third, a signal intensity correction is applied to remove artificial signal modulations due to eddy current-induced erroneous T2(∗) -weighting (i.e., Type 3 artifact). These systematic improvements will greatly increase the consistency and accuracy of DTI measurements, expanding the utility of DTI in translational applications where quantitative robustness is much needed.
Fast large scale structure perturbation theory using one-dimensional fast Fourier transforms
Schmittfull, Marcel; Vlah, Zvonimir; McDonald, Patrick
2016-05-01
The usual fluid equations describing the large-scale evolution of mass density in the universe can be written as local in the density, velocity divergence, and velocity potential fields. As a result, the perturbative expansion in small density fluctuations, usually written in terms of convolutions in Fourier space, can be written as a series of products of these fields evaluated at the same location in configuration space. Based on this, we establish a new method to numerically evaluate the 1-loop power spectrum (i.e., Fourier transform of the 2-point correlation function) with one-dimensional fast Fourier transforms. This is exact and a few orders of magnitude faster than previously used numerical approaches. Numerical results of the new method are in excellent agreement with the standard quadrature integration method. This fast model evaluation can in principle be extended to higher loop order where existing codes become painfully slow. Our approach follows by writing higher order corrections to the 2-point correlation function as, e.g., the correlation between two second-order fields or the correlation between a linear and a third-order field. These are then decomposed into products of correlations of linear fields and derivatives of linear fields. The method can also be viewed as evaluating three-dimensional Fourier space convolutions using products in configuration space, which may also be useful in other contexts where similar integrals appear.
Zarabadi, Atefeh S; Pawliszyn, Janusz
2015-02-17
Analysis in the frequency domain is considered a powerful tool to elicit precise information from spectroscopic signals. In this study, the Fourier transformation technique is employed to determine the diffusion coefficient (D) of a number of proteins in the frequency domain. Analytical approaches are investigated for determination of D from both experimental and data treatment viewpoints. The diffusion process is modeled to calculate diffusion coefficients based on the Fourier transformation solution to Fick's law equation, and its results are compared to time domain results. The simulations characterize optimum spatial and temporal conditions and demonstrate the noise tolerance of the method. The proposed model is validated by its application for the electropherograms from the diffusion path of a set of proteins. Real-time dynamic scanning is conducted to monitor dispersion by employing whole column imaging detection technology in combination with capillary isoelectric focusing (CIEF) and the imaging plug flow (iPF) experiment. These experimental techniques provide different peak shapes, which are utilized to demonstrate the Fourier transformation ability in extracting diffusion coefficients out of irregular shape signals. Experimental results confirmed that the Fourier transformation procedure substantially enhanced the accuracy of the determined values compared to those obtained in the time domain.
Double Fourier analysis for Emotion Identification in Voiced Speech
Sierra-Sosa, D.; Bastidas, M.; Ortiz P., D.; Quintero, O. L.
2016-04-01
We propose a novel analysis alternative, based on two Fourier Transforms for emotion recognition from speech. Fourier analysis allows for display and synthesizes different signals, in terms of power spectral density distributions. A spectrogram of the voice signal is obtained performing a short time Fourier Transform with Gaussian windows, this spectrogram portraits frequency related features, such as vocal tract resonances and quasi-periodic excitations during voiced sounds. Emotions induce such characteristics in speech, which become apparent in spectrogram time-frequency distributions. Later, the signal time-frequency representation from spectrogram is considered an image, and processed through a 2-dimensional Fourier Transform in order to perform the spatial Fourier analysis from it. Finally features related with emotions in voiced speech are extracted and presented.
Mathematical principles of signal processing Fourier and wavelet analysis
Brémaud, Pierre
2002-01-01
Fourier analysis is one of the most useful tools in many applied sciences. The recent developments of wavelet analysis indicates that in spite of its long history and well-established applications, the field is still one of active research. This text bridges the gap between engineering and mathematics, providing a rigorously mathematical introduction of Fourier analysis, wavelet analysis and related mathematical methods, while emphasizing their uses in signal processing and other applications in communications engineering. The interplay between Fourier series and Fourier transforms is at the heart of signal processing, which is couched most naturally in terms of the Dirac delta function and Lebesgue integrals. The exposition is organized into four parts. The first is a discussion of one-dimensional Fourier theory, including the classical results on convergence and the Poisson sum formula. The second part is devoted to the mathematical foundations of signal processing - sampling, filtering, digital signal proc...
Image restoration based on the discrete fraction Fourier transform
Yan, Peimin; Mo, Yu L.; Liu, Hong
2001-09-01
The fractional Fourier transform is the powerful tool for time-variant signal analysis. For space-variant degradation and non-stationary processes the filtering in fractional Fourier domains permits reduction of the error compared with ordinary Fourier domain filtering. In this paper the concept of filtering in fractional Fourier domains is applied to the problem of estimating degraded images. Efficient digital implementation using discrete Hermite eigenvectors can provide similar results to match the continuous outputs. Expressions for the 2D optimal filter function in fractional domains will be given for transform domains characterized by the two rotation angle parameters of the 2D fractional Fourier transform. The proposed method is used to restore images that have several degradations in the experiments. The results show that the method presented in this paper is valid.
Osbin, K.; Jayan, Manuel; Bhadrakumari, S.; Predeep, P.
2017-06-01
This study investigates the presence of various amide bands present in different spider silk species, which provides extraordinary physical properties. Three different spider silks were collected from Western Ghats region. The collected spider silks samples belonging to the spider Heteropoda venatoria (species 1), Hersilia savignyi (species 2) and Pholcus phalangioides (species 3). Fourier transform infrared (FTIR) spectra reveals the protein peaks in the amide I, II, and III regions in all the three types of spider silk species.
Thermal stabilization of static single-mirror Fourier transform spectrometers
Schardt, Michael; Schwaller, Christian; Tremmel, Anton J.; Koch, Alexander W.
2017-05-01
Fourier transform spectroscopy has become a standard method for spectral analysis of infrared light. With this method, an interferogram is created by two beam interference which is subsequently Fourier-transformed. Most Fourier transform spectrometers used today provide the interferogram in the temporal domain. In contrast, static Fourier transform spectrometers generate interferograms in the spatial domain. One example of this type of spectrometer is the static single-mirror Fourier transform spectrometer which offers a high etendue in combination with a simple, miniaturized optics design. As no moving parts are required, it also features a high vibration resistance and high measurement rates. However, it is susceptible to temperature variations. In this paper, we therefore discuss the main sources for temperature-induced errors in static single-mirror Fourier transform spectrometers: changes in the refractive index of the optical components used, variations of the detector sensitivity, and thermal expansion of the housing. As these errors manifest themselves in temperature-dependent wavenumber shifts and intensity shifts, they prevent static single-mirror Fourier transform spectrometers from delivering long-term stable spectra. To eliminate these shifts, we additionally present a work concept for the thermal stabilization of the spectrometer. With this stabilization, static single-mirror Fourier transform spectrometers are made suitable for infrared process spectroscopy under harsh thermal environmental conditions. As the static single-mirror Fourier transform spectrometer uses the so-called source-doubling principle, many of the mentioned findings are transferable to other designs of static Fourier transform spectrometers based on the same principle.
En kritisk analyse af Leviathan & Samfundspagten
Bjelobrk, Aleksandar
2006-01-01
I denne rapport undersøges de politiske filosoffer Thomas Hobbes’ (1588-1679) og Jean-Jacques Rousseaus (1712-1778) udgaver af kontraktteorien. Med udgangspunkt i Leviathan del 1, Of Man og del 2, Of Common-Wealth af Thomas Hobbes (Hobbes 1991, oprindelig udgivet 1651) og Samfundspagten af Jean-Jacques Rousseau (Rousseau 1987, oprindelig udgivet 1762) klarlægges inkonsisten i deres teorier gennem to separate analyser. Med udgangspunkt i den fundne inkonsistens foretages en komparativ analyse,...
Sen, Sanchari; Desai, Darshan B.; Alsubaie, Meznh H.; Zhelyeznyakov, Maksym V.; Molina, L.; Sarraf, Hamed Sari; Bernussi, Ayrton A.; Peralta, Luis Grave de
2017-01-01
Fourier plane imaging (FPIM) and Fourier ptychographic (FPM) microscopy techniques were used to image photonic crystals. A computer-controlled hemispherical digital condenser provided required sample illumination with variable inclination. Notable improvement in image resolution was obtained with both methods. However, it was determined that the FPM technique cannot surpass the Rayleigh resolution limit when imaging photonic crystals.
Estimation of time of death with a fourier series unsteady-state heat transfer model.
Smart, Jimmy L
2010-11-01
The purpose of this study was to return to fundamental principles of heat transfer and derive a suitable model to establish a firm basis for constructing a postmortem human cooling curve. A Fourier Series Model was successfully applied to unsteady heat transfer within a wooden cylinder in controlled laboratory conditions. Wood has similar thermal diffusivity properties as human tissue. By manipulation of the model, sensitivity analyses were performed to observe the impact of changes in values of input variables. Variables of initial temperature of the cylinder and ambient surrounding temperature were shown to be very sensitive and have the most impact upon predictive results of the model. The model was also used to demonstrate the existence of an initial temperature plateau, which is often the subject of controversy in estimating time of death. Finally, it was demonstrated how the Fourier Series Model can be applied to estimate time of death for humans.
Fractional Fourier transform for partially coherent beam in spatial-frequency domain
Institute of Scientific and Technical Information of China (English)
Cai Yang-Jian; Lin Qiang
2004-01-01
By using Fourier transform and the tensor analysis method, the fractional Fourier transform (FRT) in the spatialfrequency domain for partially coherent beams is derived. Based on the FRT in the spatial-frequency domain, an analytical transform formula is derived for a partially coherent twisted anisotropic Gaussian-Schell model (GSM) beam passing through the FRT system. The connections between the FRT formula and the generalized diffraction integral formulae for partially coherent beams through an aligned optical system and a misaligned optical system in the spatialfrequency domain are discussed, separately. By using the derived formula, the intensity distribution of partially coherent twisted anisotropic GSM beams in the FRT plane are studied in detail. The formula derived provide a convenient tool for analysing and calculating the FRTs of the partially coherent beams in spatial-frequency domain.
Cryogenic Scan Mechanism for Fourier Transform Spectrometer
Brasunas, John C.; Francis, John L.
2011-01-01
A compact and lightweight mechanism has been developed to accurately move a Fourier transform spectrometer (FTS) scan mirror (a cube corner) in a near-linear fashion with near constant speed at cryogenic temperatures. This innovation includes a slide mechanism to restrict motion to one dimension, an actuator to drive the motion, and a linear velocity transducer (LVT) to measure the speed. The cube corner mirror is double-passed in one arm of the FTS; double-passing is required to compensate for optical beam shear resulting from tilting of the moving cube corner. The slide, actuator, and LVT are off-the-shelf components that are capable of cryogenic vacuum operation. The actuator drives the slide for the required travel of 2.5 cm. The LVT measures translation speed. A proportional feedback loop compares the LVT voltage with the set voltage (speed) to derive an error signal to drive the actuator and achieve near constant speed. When the end of the scan is reached, a personal computer reverses the set voltage. The actuator and LVT have no moving parts in contact, and have magnetic properties consistent with cryogenic operation. The unlubricated slide restricts motion to linear travel, using crossed roller bearings consistent with 100-million- stroke operation. The mechanism tilts several arc seconds during transport of the FTS mirror, which would compromise optical fringe efficiency when using a flat mirror. Consequently, a cube corner mirror is used, which converts a tilt into a shear. The sheared beam strikes (at normal incidence) a flat mirror at the end of the FTS arm with the moving mechanism, thereby returning upon itself and compensating for the shear
Emerson, Tegan; Kirby, Michael; Bethel, Kelly; Kolatkar, Anand; Luttgen, Madelyn; O'Hara, Stephen; Newton, Paul; Kuhn, Peter
2015-03-01
We address the problem of subclassification of rare circulating cells using data driven feature selection from images of candidate circulating tumor cells from patients diagnosed with breast, prostate, or lung cancer. We determine a set of low level features which can differentiate among candidate cell types. We have implemented an image representation based on concentric Fourier rings (FRDs) which allow us to exploit size variations and morphological differences among cells while being rotationally invariant. We discuss potential clinical use in the context of treatment monitoring for cancer patients with metastatic disease.
A transformada de Fourier em basic The Fourier transform (FFT in basic
Directory of Open Access Journals (Sweden)
Mauricio Gomes Constantino
2000-06-01
Full Text Available In this paper we describe three computer programs in Basic language about the Fourier transform (FFT which are available in the Internet site http://artemis.ffclrp.usp.br/SoftwareE.htm (in English or http://artemis.ffclrp.usp.br/softwareP.htm (in Portuguese since October 1998. Those are addresses to the Web Page of our Laboratory of Organic Synthesis. The programs can be downloaded and used by anyone who is interested on the subject. The texts, menus and captions in the programs are written in English.
Mastroianni, S; Heinz, F D; Im, J-H; Veurman, W; Padilla, M; Schubert, M C; Würfel, U; Grätzel, M; Park, N-G; Hinsch, A
2015-12-14
CH3NH3PbI3 perovskite solar cells with a mesoporous TiO2 layer and spiro-MeOTAD as a hole transport layer (HTL) with three different CH3NH3I concentrations (0.032 M, 0.044 M and 0.063 M) were investigated. Strong variations in crystal size and morphology resulting in diversified cell efficiencies (9.2%, 16.9% and 12.3%, respectively) were observed. The physical origin of this behaviour was analysed by detailed characterization combining current-voltage curves with photo- and electroluminescence (PL and EL) imaging as well as light beam induced current measurements (LBIC). It was found that the most efficient cell shows the highest luminescence and the least efficient cell is most strongly limited by non-radiative recombination. Crystal size, morphology and distribution in the capping layer and in the porous scaffold strongly affect the non-radiative recombination. Moreover, the very non-uniform crystal structure with multiple facets, as evidenced by SEM images of the 0.032 M device, suggests the creation of a large number of grain boundaries and crystal dislocations. These defects give rise to increased trap-assisted non-radiative recombination as is confirmed by high-resolution μ-PL images. The different imaging techniques used in this study prove to be well-suited to spatially investigate and thus correlate the crystal morphology of the perovskite layer with the electrical and radiative properties of the solar cells and thus with their performance.
Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Brown, D. N.; Kolomensky, Yu. G.; Koch, H.; Schroeder, T.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; So, R. Y.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Lankford, A. J.; Gary, J. W.; Long, O.; Eisner, A. M.; Lockman, W. S.; Panduro Vazquez, W.; Chao, D. S.; Cheng, C. H.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Kim, J.; Miyashita, T. S.; Ongmongkolkul, P.; Porter, F. C.; Röhrken, M.; Huard, Z.; Meadows, B. T.; Pushpawela, B. G.; Sokoloff, M. D.; Sun, L.; Smith, J. G.; Wagner, S. R.; Bernard, D.; Verderi, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Santoro, V.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Martellotti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Zallo, A.; Passaggio, S.; Patrignani, C.; Bhuyan, B.; Mallik, U.; Chen, C.; Cochran, J.; Prell, S.; Ahmed, H.; Pennington, M. R.; Gritsan, A. V.; Arnaud, N.; Davier, M.; Le Diberder, F.; Lutz, A. M.; Wormser, G.; Lange, D. J.; Wright, D. M.; Coleman, J. P.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Cowan, G.; Banerjee, Sw.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Griessinger, K.; Hafner, A.; Schubert, K. R.; Barlow, R. J.; Lafferty, G. D.; Cenci, R.; Jawahery, A.; Roberts, D. A.; Cowan, R.; Cheaib, R.; Robertson, S. H.; Dey, B.; Neri, N.; Palombo, F.; Cremaldi, L.; Godang, R.; Summers, D. J.; Taras, P.; De Nardo, G.; Sciacca, C.; Raven, G.; Jessop, C. P.; LoSecco, J. M.; Honscheid, K.; Kass, R.; Gaz, A.; Margoni, M.; Posocco, M.; Rotondo, M.; Simi, G.; Simonetto, F.; Stroili, R.; Akar, S.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Calderini, G.; Chauveau, J.; Marchiori, G.; Ocariz, J.; Biasini, M.; Manoni, E.; Rossi, A.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Chrzaszcz, M.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Rama, M.; Rizzo, G.; Walsh, J. J.; Smith, A. J. S.; Anulli, F.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Pilloni, A.; Piredda, G.; Bünger, C.; Dittrich, S.; Grünberg, O.; Heß, M.; Leddig, T.; Voß, C.; Waldi, R.; Adye, T.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Aston, D.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dunwoodie, W.; Ebert, M.; Field, R. C.; Fulsom, B. G.; Graham, M. T.; Hast, C.; Innes, W. R.; Kim, P.; Leith, D. W. G. S.; Luitz, S.; Luth, V.; MacFarlane, D. B.; Muller, D. R.; Neal, H.; Ratcliff, B. N.; Roodman, A.; Sullivan, M. K.; Va'vra, J.; Wisniewski, W. J.; Purohit, M. V.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Burchat, P. R.; Puccio, E. M. T.; Alam, M. S.; Ernst, J. A.; Gorodeisky, R.; Guttman, N.; Peimer, D. R.; Soffer, A.; Spanier, S. M.; Ritchie, J. L.; Schwitters, R. F.; Izen, J. M.; Lou, X. C.; Bianchi, F.; De Mori, F.; Filippi, A.; Gamba, D.; Lanceri, L.; Vitale, L.; Martinez-Vidal, F.; Oyanguren, A.; Albert, J.; Beaulieu, A.; Bernlochner, F. U.; King, G. J.; Kowalewski, R.; Lueck, T.; Nugent, I. M.; Roney, J. M.; Tasneem, N.; Gershon, T. J.; Harrison, P. F.; Latham, T. E.; Prepost, R.; Wu, S. L.; BaBar Collaboration
2016-01-01
We study the processes γ γ →KS0K±π∓ and γ γ →K+K-π0 using a data sample of 519 fb-1 recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+e- collider at center-of-mass energies at and near the Υ (n S ) (n =2 , 3, 4) resonances. We observe ηc decays to both final states and perform Dalitz plot analyses using a model-independent partial wave analysis technique. This allows a model-independent measurement of the mass-dependence of the I =1 /2 K π S -wave amplitude and phase. A comparison between the present measurement and those from previous experiments indicates similar behavior for the phase up to a mass of 1.5 GeV /c2. In contrast, the amplitudes show very marked differences. The data require the presence of a new a0(1950 ) resonance with parameters m =1931 ±14 ±22 MeV /c2 and Γ =271 ±22 ±29 MeV .
Fourier transform infrared absorption spectroscopy of jet-cooled radicals
Rohrs, Henry W.; Wickham-Jones, C. Tom; Ellison, G. Barney; Berry, David; Argrow, Brian M.
1995-03-01
We describe an experiment that couples a high-resolution Fourier transform spectrometer (FTS) to a supersonic jet of radicals. A 1-mm-i.d. cylindrical SiC nozzle is resistively heated to 1500 K in order to decompose organic precursors and generate expansions of jet-cooled radicals. We have used this apparatus to pyrolyze alkyl nitrites to make alkoxy and nitric oxide radicals. The residence time of radicals in this hot nozzle is roughly 20 μs RONO→ΔRO+NO. We use the FTS to detect the IR absorption of the product NO (ν0=1876.1 cm-1) at resolutions as fine as 0.005 cm-1 FWHM. We observe the product NO from the pyrolysis of CH3CH2ONO to be rotationally cooled to roughly 50 K. The IR spectra indicate that the optical path length is about 3/4 cm and that the nitrites pyrolyze to produce approximately 1014 NO radicals cm-3 some 9 mm downstream from the nozzle. Our spectrometer is capable of detecting an absorption signal of 0.1% over a bandwidth of 100 cm-1 at 0.005 cm-1 resolution. Depending on the infrared cross section of the radical, this implies that we are able to monitor diatomic radical densities of roughly 5×1012 cm-3 (quantum state)-1.
Spin Glass Field Theory with Replica Fourier Transforms
Pimentel, Iveta R.; De Dominicis, Cirano
We develop a field theory for spin glasses using Replica Fourier Transforms (RFT). We present the formalism for the case of replica symmetry and the case of replica symmetry breaking on an ultrametric tree, with the number of replicas n and the number of replica symmetry breaking steps R generic integers. We show how the RFT applied to the two-replica fields allows to construct a new basis which block-diagonalizes the four-replica mass-matrix, into the replicon, anomalous and longitudinal modes. The eigenvalues are given in terms of the mass RFT and the propagators in the RFT space are obtained by inversion of the block-diagonal matrix. The formalism allows to express any i-replica vertex in the new RFT basis and hence enables to perform a standard perturbation expansion. We apply the formalism to calculate the contribution of the Gaussian fluctuations around the Parisi's solution for the free-energy of an Ising spin glass.
Grid-Based Fourier Transform Phase Contrast Imaging
Tahir, Sajjad
Low contrast in x-ray attenuation imaging between different materials of low electron density is a limitation of traditional x-ray radiography. Phase contrast imaging offers the potential to improve the contrast between such materials, but due to the requirements on the spatial coherence of the x-ray beam, practical implementation of such systems with tabletop (i.e. non-synchrotron) sources has been limited. One recently developed phase imaging technique employs multiple fine-pitched gratings. However, the strict manufacturing tolerances and precise alignment requirements have limited the widespread adoption of grating-based techniques. In this work, we have investigated a technique recently demonstrated by Bennett et al. that utilizes a single grid of much coarser pitch. Our system consisted of a low power 100 microm spot Mo source, a CCD with 22 microm pixel pitch, and either a focused mammography linear grid or a stainless steel woven mesh. Phase is extracted from a single image by windowing and comparing data localized about harmonics of the grid in the Fourier domain. A Matlab code was written to perform the image processing. For the first time, the effects on the diffraction phase contrast and scattering amplitude images of varying grid types and periods, and of varying the window function type used to separate the harmonics, and the window widths, were investigated. Using the wire mesh, derivatives of the phase along two orthogonal directions were obtained and new methods investigated to form improved phase contrast images.
Chiral Process Monitoring Using Fourier Transform Microwave Spectroscopy
Neill, Justin L.; Muckle, Matt; Pate, Brooks
2017-06-01
We present the application of Fourier transform microwave (FTMW) spectroscopy in monitoring the chiral purity of components in a reaction mixture. This is of particular interest due to the increasing use of continuous pharmaceutical manufacturing processes, in which a number of attributes (including the chiral purity of the product) can change on short time scales. Therefore, new techniques that can accomplish this measurement rapidly are desired. The excellent specificity of FTMW spectroscopy, coupled with newly developed techniques for measuring enantiomeric excess in a mixture, have motivated this work. In collaboration with B. Frank Gupton (Virginia Commonwealth University), we are testing this application first with the synthesis of artemisinin. Artemisinin, a common drug for malaria treatment, is of high global health interest and subject to supply shortages, and therefore a strong candidate for continuous manufacturing. It also has moderately high molecular weight (282 amu) and seven chiral centers, making it a good candidate to test the capabilities of FTMW spectroscopy. Using a miniature cavity-enhanced FTMW spectrometer design, we aim to demonstrate selective component quantification in the reaction mixture. Future work that will be needed to fully realize this application will be discussed. R.D. Suenram, J.U. Grabow, A.Zuban, and I.Leonov, Rev. Sci. Instrum. 70, 2127 (1999).
Mesh-based phase contrast Fourier transform imaging
Tahir, Sajjad; Bashir, Sajid; MacDonald, C. A.; Petruccelli, Jonathan C.
2017-04-01
Traditional x-ray radiography is limited by low attenuation contrast in materials of low electron density. Phase contrast imaging offers the potential to improve the contrast between such materials, but due to the requirements on the spatial coherence of the x-ray beam, practical implementation of such systems with tabletop (i.e. non-synchrotron) sources has been limited. One phase imaging technique employs multiple fine-pitched gratings. However, the strict manufacturing tolerances and precise alignment requirements have limited the widespread adoption of grating-based techniques. In this work, we have investigated a recently developed technique that utilizes a single grid of much coarser pitch. Our system consisted of a low power 100 μm spot Mo source, a CCD with 22 μm pixel pitch, and either a focused mammography linear grid or a stainless steel woven mesh. Phase is extracted from a single image by windowing and comparing data localized about harmonics of the mesh in the Fourier domain. The effects on the diffraction phase contrast and scattering amplitude images of varying grid types and periods, and of varying the width of the window function used to separate the harmonics were investigated. Using the wire mesh, derivatives of the phase along two orthogonal directions were obtained and combined to form improved phase contrast images.
Directory of Open Access Journals (Sweden)
Claudia Menzel
Full Text Available We investigated whether low-level processed image properties that are shared by natural scenes and artworks - but not veridical face photographs - affect the perception of facial attractiveness and age. Specifically, we considered the slope of the radially averaged Fourier power spectrum in a log-log plot. This slope is a measure of the distribution of special frequency power in an image. Images of natural scenes and artworks possess - compared to face images - a relatively shallow slope (i.e., increased high spatial frequency power. Since aesthetic perception might be based on the efficient processing of images with natural scene statistics, we assumed that the perception of facial attractiveness might also be affected by these properties. We calculated Fourier slope and other beauty-associated measurements in face images and correlated them with ratings of attractiveness and age of the depicted persons (Study 1. We found that Fourier slope - in contrast to the other tested image properties - did not predict attractiveness ratings when we controlled for age. In Study 2A, we overlaid face images with random-phase patterns with different statistics. Patterns with a slope similar to those in natural scenes and artworks resulted in lower attractiveness and higher age ratings. In Studies 2B and 2C, we directly manipulated the Fourier slope of face images and found that images with shallower slopes were rated as more attractive. Additionally, attractiveness of unaltered faces was affected by the Fourier slope of a random-phase background (Study 3. Faces in front of backgrounds with statistics similar to natural scenes and faces were rated as more attractive. We conclude that facial attractiveness ratings are affected by specific image properties. An explanation might be the efficient coding hypothesis.
Menzel, Claudia; Hayn-Leichsenring, Gregor U; Langner, Oliver; Wiese, Holger; Redies, Christoph
2015-01-01
We investigated whether low-level processed image properties that are shared by natural scenes and artworks - but not veridical face photographs - affect the perception of facial attractiveness and age. Specifically, we considered the slope of the radially averaged Fourier power spectrum in a log-log plot. This slope is a measure of the distribution of special frequency power in an image. Images of natural scenes and artworks possess - compared to face images - a relatively shallow slope (i.e., increased high spatial frequency power). Since aesthetic perception might be based on the efficient processing of images with natural scene statistics, we assumed that the perception of facial attractiveness might also be affected by these properties. We calculated Fourier slope and other beauty-associated measurements in face images and correlated them with ratings of attractiveness and age of the depicted persons (Study 1). We found that Fourier slope - in contrast to the other tested image properties - did not predict attractiveness ratings when we controlled for age. In Study 2A, we overlaid face images with random-phase patterns with different statistics. Patterns with a slope similar to those in natural scenes and artworks resulted in lower attractiveness and higher age ratings. In Studies 2B and 2C, we directly manipulated the Fourier slope of face images and found that images with shallower slopes were rated as more attractive. Additionally, attractiveness of unaltered faces was affected by the Fourier slope of a random-phase background (Study 3). Faces in front of backgrounds with statistics similar to natural scenes and faces were rated as more attractive. We conclude that facial attractiveness ratings are affected by specific image properties. An explanation might be the efficient coding hypothesis.
ISAR Imaging Using Fourier and Wavelet Transforms
2007-12-01
for i=1:45; Imf2=SFABS(1,:,i); Image2=[Image2;Imf2]; end 60 LIST OF REFERENCES [1] George Arfken . Mathematical Methods for Physicists, volume Third...arcs that can be approximated as lines. Consequently, the imaging method is mathematically the same as that used in Inverse Synthetic Aperture Radar...and why it’s not a good approach to our problem. We investigate the results using this time-frequency methods , creating images using synthetic data
Description of dental arch form using the Fourier series.
Valenzuela, A Patricia; Pardo, Marco A; Yezioro, Salomon
2002-01-01
The aim of this study was to describe the form of the human superior dental arch using Fourier transformations. Forty models made in dental stone from impressions of the maxillary dental arch were used to obtain the reference data, which were expressed in Cartesian coordinates, from the mesovestibular cuspid vertices of molar teeth, vestibular cuspid of premolars, and incisal edge. Fourth-grade equations and Fourier series were calculated from these data. The results indicate that Fourier series more precisely express the form and size of different dental arches, with mixed or permanent dentition, than fourth-grade equations. Details of the mathematical procedure and the precision obtained were provided.
Brief notes in advanced DSP Fourier analysis with Matlab
Grigoryan, Artyom M
2009-01-01
Based on the authors' research in Fourier analysis, Brief Notes in Advanced DSP: Fourier Analysis with MATLAB® addresses many concepts and applications of digital signal processing (DSP). The included MATLAB® codes illustrate how to apply the ideas in practice.The book begins with the basic concept of the discrete Fourier transformation and its properties. It then describes lifting schemes, integer transformations, the discrete cosine transform, and the paired transform method for calculating the discrete Hadamard transform. The text also examines the decomposition of the 1D signal by so-calle
Preliminary Analysis of ULPC Light Curves Using Fourier Decomposition Technique
Ngeow, Chow-Choong; Kanbur, Shashi; Barrett, Brittany; Lin, Bin
2013-01-01
Recent work on Ultra Long Period Cepheids (ULPCs) has suggested their usefulness as a distance indicator, but has not commented on their relationship as compared with other types of variable stars. In this work, we use Fourier analysis to quantify the structure of ULPC light curves and compare them to Classical Cepheids and Mira variables. Our preliminary results suggest that the low order Fourier parameters of ULPCs show a continuous trend defined by Classical Cepheids after the resonance around 10 days. However their Fourier parameters also overlapped with those from Miras, which make the classification of long period variable stars difficult based on the light curves information alone.
Double random fractional Fourier domain encoding for optical security
Unnikrishnan, G.; Singh, Kehar
2000-11-01
We propose a new optical encryption technique using the fractional Fourier transform. In this method, the data are encrypted to a stationary white noise by two statistically independent random phase masks in fractional Fourier domains. To decrypt the data correctly, one needs to specify the fractional domains in which the input plane, encryption plane, and output planes exist, in addition to the key used for encryption. The use of an anamorphic fractional Fourier transform for the encryption of 2D data is also discussed. We suggest an optical implementation of the proposed idea. Results of a numerical simulation to analyze the performance of the proposed method are presented.
Fractional Fourier transform of apertured paraboloid refracting system
Institute of Scientific and Technical Information of China (English)
Jiannong Chen; Jinliang Yan; Defa Wang; Yongjiang Yu
2007-01-01
The limitation of paraxial condition of paraboloid refracting system in performing fractional Fourier transform acts like an aperture, which makes the system different from ideal systems. With aperture expanded as the sum of finite complex Gaussian terms, a more practical approximate analytical solution of fractional Fourier transform of Gaussian beam in an apertured paraboloid refracting system is obtained and also numerical investigation is presented. Complicated and practical fractional Fourier transform systems can be constructed by cascading several apertured paraboloid refracting systems which are the simplest and the most basic units for performing more precise transform.
Accelerating the Fourier split operator method via graphics processing units
Bauke, Heiko
2010-01-01
Current generations of graphics processing units have turned into highly parallel devices with general computing capabilities. Thus, graphics processing units may be utilized, for example, to solve time dependent partial differential equations by the Fourier split operator method. In this contribution, we demonstrate that graphics processing units are capable to calculate fast Fourier transforms much more efficiently than traditional central processing units. Thus, graphics processing units render efficient implementations of the Fourier split operator method possible. Performance gains of more than an order of magnitude as compared to implementations for traditional central processing units are reached in the solution of the time dependent Schr\\"odinger equation and the time dependent Dirac equation.
Wolkers, W.F.; Hoekstra, F.A.
1997-01-01
Secondary structure and aggregation behavior of proteins, as determined in situ in Typha latifolia pollen, were studied by means of Fourier transform infrared microspectroscopy. The amide-I band, arising from the peptide backbone, was recorded over a temperature range from -50 to 120°C at different
Comparative analysis of imaging configurations and objectives for Fourier microscopy
Kurvits, Jonathan A; Zia, Rashid
2015-01-01
Fourier microscopy is becoming an increasingly important tool for the analysis of optical nanostructures and quantum emitters. However, achieving quantitative Fourier space measurements requires a thorough understanding of the impact of aberrations introduced by optical microscopes, which have been optimized for conventional real-space imaging. Here, we present a detailed framework for analyzing the performance of microscope objectives for several common Fourier imaging configurations. To this end, we model objectives from Nikon, Olympus, and Zeiss using parameters that were inferred from patent literature and confirmed, where possible, by physical disassembly. We then examine the aberrations most relevant to Fourier microscopy, including the alignment tolerances of apodization factors for different objective classes, the effect of magnification on the modulation transfer function, and vignetting-induced reductions of the effective numerical aperture for wide-field measurements. Based on this analysis, we ide...
Numerical analysis of the human nostril by the Fourier series.
Goto, M; Katsuki, T
1990-02-01
Fourier series has been applied in a numerical analysis of the human nostril morphology. The relationship between the nostril form and the Fourier coefficients was examined: the constant affected the size, the first term determined the roundness, and the second term determined the flatness of the morphology. The inclination of the apse line was calculated from the phase of the second term. Ninety-five standardized nostril photographs were analyzed by Fourier series: 48 of adult Japanese females and 47 of German females. The German nostril was larger in size, flatter in shape, and the apse line closer to the sagittal plane than the Japanese counterpart. As a clinical application of nostril digitization, pre- and post-operative cleft lip noses were analyzed. Fourier analysis has proved to be useful in a numerical evaluation of morphological differences of, and post-operative changes made to, the nostril.
Matrix summability of the conjugate deries of derived Fourier series
Directory of Open Access Journals (Sweden)
Shyam Lal
2002-03-01
Full Text Available In this paper, a new theorem on matrix summability of the conjugate series of a derived Fourier series is proved, which improves and generalizes all the previous known results in this line of work.
Fourier optics through the looking glass of digital computers
Yaroslavsky, Leonid P.
2011-10-01
Optical transforms are represented in computers by their discrete versions. In particular, Fourier optics is represented through Discrete Fourier Transform (DFT) and Discrete Cosine Transform (DCT). Being discrete representation of the optical Fourier transform, these transforms feature a number of peculiarities that cast a new light on such fundamental properties of the Fourier Transform as sampling theorem and the uncertainty principle. In this paper, we formulate the Discrete Sampling Theorem and the discrete uncertainty principle, demonstrate that discrete signals can be both bandlimited in DFT or DCT domains and have strictly limited support in signal domain and present examples of such "bandlimited/ space-limited" signals that remain to be so for whatever large of their samples.
Fourier spectra from exoplanets with polar caps and ocean glint
Visser, P M
2015-01-01
The weak orbital-phase dependent reflection signal of an exoplanet contains information on the planet surface, such as the distribution of continents and oceans on terrestrial planets. This light curve is usually studied in the time domain, but because the signal from a stationary surface is (quasi)periodic, analysis of the Fourier series may provide an alternative, complementary approach. We study Fourier spectra from reflected light curves for geometrically simple configurations. Depending on its atmospheric properties, a rotating planet in the habitable zone could have circular polar ice caps. Tidally locked planets, on the other hand, may have symmetric circular oceans facing the star. These cases are interesting because the high-albedo contrast at the sharp edges of the ice-sheets and the glint from the host star in the ocean may produce recognizable light curves with orbital periodicity, which could also be interpreted in the Fourier domain. We derive a simple general expression for the Fourier coeffici...
Imaging Analysis by Means of Fractional Fourier Transform
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Starting from the diffraction imaging process,we have discussed the relationship between optical imaging system and fractional Fourier transform, and proposed a specific system which can form an inverse amplified image of input function.
Electro-Optic Imaging Fourier Transform Spectral Polarimeter Project
National Aeronautics and Space Administration — Boulder Nonlinear Systems, Inc. (BNS) proposes to develop an Electro-Optic Imaging Fourier Transform Spectral Polarimeter (E-O IFTSP). The polarimetric system is...
On the physical relevance of the discrete Fourier transform
CSIR Research Space (South Africa)
Greben, JM
1991-11-01
Full Text Available This paper originated from the author's dissatisfaction with the way the discrete Fourier transform is usually presented in the literature. Although mathematically correct, the physical meaning of the common representation is unsatisfactory...
Embolic Doppler ultrasound signal detection via fractional Fourier transform.
Gençer, Merve; Bilgin, Gökhan; Aydın, Nizamettin
2013-01-01
Computerized analysis of Doppler ultrasound signals can aid early detection of asymptomatic circulating emboli. For analysis, physicians use informative features extracted from Doppler ultrasound signals. Time -frequency analysis methods are useful tools to exploit the transient like signals such as Embolic signals. Detection of discriminative features would be the first step toward automated analysis of embolic Doppler ultrasound signals. The most problematic part of setting up emboli detection system is to differentiate embolic signals from confusing similar wave-like patterns such as Doppler speckle and artifacts caused by tissue movement, probe tapping, speaking etc. In this study, discrete version of fractional Fourier transform is presented as a solution in the detection of emboli in digitized Doppler ultrasound signals. An accurate set of parameters are extracted using short time Fourier transform and fractional Fourier transform and the results are compared to reveal detection quality. Experimental results prove the efficiency of fractional Fourier transform in which discriminative features becomes more evident.
Methods of theme presentation "The Fourier transform of impulse functions"
Directory of Open Access Journals (Sweden)
Faniya Ahmetova
2016-09-01
Full Text Available The paper considers the Fourier transform of impulse functions, which is the mathematical basis of the tasks associated with the theory of reception and signal conversion in optoelectronic system. The method of calculating of two functions convolution, its Fourier image and the image of the Fourier-Bessel axisymmetric functions are demonstrated in details. A table, which summarizes the analytical expression for the shifted impulse functions and records their Fourier transforms, is provided. A wide range of examples of solving tasks, containing the graphic illustration, is analyzed. A structured approach to the presentation of the material, which combines basic theoretical information and analysis of typical tasks, will help second-year students of optoelectronic specialty in their independent work and homework.
Extending single-molecule microscopy using optical Fourier processing.
Backer, Adam S; Moerner, W E
2014-07-17
This article surveys the recent application of optical Fourier processing to the long-established but still expanding field of single-molecule imaging and microscopy. A variety of single-molecule studies can benefit from the additional image information that can be obtained by modulating the Fourier, or pupil, plane of a widefield microscope. After briefly reviewing several current applications, we present a comprehensive and computationally efficient theoretical model for simulating single-molecule fluorescence as it propagates through an imaging system. Furthermore, we describe how phase/amplitude-modulating optics inserted in the imaging pathway may be modeled, especially at the Fourier plane. Finally, we discuss selected recent applications of Fourier processing methods to measure the orientation, depth, and rotational mobility of single fluorescent molecules.
On Sums of Numerical Series and Fourier Series
Pavao, H. Germano; de Oliveira, E. Capelas
2008-01-01
We discuss a class of trigonometric functions whose corresponding Fourier series, on a conveniently chosen interval, can be used to calculate several numerical series. Particular cases are presented and two recent results involving numerical series are recovered. (Contains 1 note.)
On the Equisummability of Hermite and Fourier Expansions
Indian Academy of Sciences (India)
E K Narayanan; S Thangavelu
2001-02-01
We prove an equisummability result for the Fourier expansions and Hermite expansions as well as special Hermite expansions. We also prove the uniform boundedness of the Bochner-Riesz means associated to the Hermite expansions for polyradial functions.
Decay properties of linear thermoelastic plates: Cattaneo versus Fourier law
Said-Houari, Belkacem
2013-02-01
In this article, we investigate the decay properties of the linear thermoelastic plate equations in the whole space for both Fourier and Cattaneo\\'s laws of heat conduction. We point out that while the paradox of infinite propagation speed inherent in Fourier\\'s law is removed by changing to the Cattaneo law, the latter always leads to a loss of regularity of the solution. The main tool used to prove our results is the energy method in the Fourier space together with some integral estimates. We prove the decay estimates for initial data U0 ∈ Hs(ℝ) ∩ L1(ℝ). In addition, by restricting the initial data to U0 ∈ Hs(ℝ) ∩ L1,γ(ℝ) and γ ∈ [0, 1], we can derive faster decay estimates with the decay rate improvement by a factor of t-γ/2. © 2013 Copyright Taylor and Francis Group, LLC.
Closed-loop Dynamic Parameter Identification of Robot Manipulators Using Modified Fourier Series
Directory of Open Access Journals (Sweden)
Wenxiang Wu
2012-05-01
Full Text Available This paper concerns the problem of dynamic parameter identification of robot manipulators and proposes a closed‐loop identification procedure using modified Fourier series (MFS as exciting trajectories. First, a static continuous friction model is involved to model joint friction for realizable friction compensation in controller design. Second, MFS satisfying the boundary conditions are firstly designed as periodic exciting trajectories. To minimize the sensitivity to measurement noise, the coefficients of MFS are optimized according to the condition number criterion. Moreover, to obtain accurate parameter estimates, the maximum likelihood estimation (MLE method considering the influence of measurement noise is adopted. The proposed identification procedure has been implemented on the first three axes of the QIANJIANG‐I 6‐DOF robot manipulator. Experiment results verify the effectiveness of the proposed approach, and comparison between identification using MFS and that using finite Fourier series (FFS reveals that the proposed method achieves better identification accuracy.
Closed-Loop Dynamic Parameter Identification of Robot Manipulators Using Modified Fourier Series
Directory of Open Access Journals (Sweden)
Wenxiang Wu
2012-05-01
Full Text Available This paper concerns the problem of dynamic parameter identification of robot manipulators and proposes a closed-loop identification procedure using modified Fourier series (MFS as exciting trajectories. First, a static continuous friction model is involved to model joint friction for realizable friction compensation in controller design. Second, MFS satisfying the boundary conditions are firstly designed as periodic exciting trajectories. To minimize the sensitivity to measurement noise, the coefficients of MFS are optimized according to the condition number criterion. Moreover, to obtain accurate parameter estimates, the maximum likelihood estimation (MLE method considering the influence of measurement noise is adopted. The proposed identification procedure has been implemented on the first three axes of the QIANJIANG-I 6-DOF robot manipulator. Experiment results verify the effectiveness of the proposed approach, and comparison between identification using MFS and that using finite Fourier series (FFS reveals that the proposed method achieves better identification accuracy.
Gómez-Polo, C.; Vázquez, M.; Knobel, M.
2001-01-01
A method to investigate the giant magnetoimpedance effect based on Fourier analysis is introduced. The study is carried out on a FeCoSiB amorphous wire with vanishing magnetostriction subjected to joule heating (current annealing) treatment that induces an enhancement of circumferential magnetic anisotropy and modifies the magnetoimpedance response of the samples. Experimental results are interpreted within the framework of the classical electrodynamical model, where the circumferential permeability plays the dominant role in the field dependence of the complex impedance of the sample. A rotational magnetization model is employed to determine the circular magnetization process, and a mean value of the circumferential permeability is obtained through the harmonic components obtained through Fourier analysis of the time derivative of the circular magnetization. This simple model is able to reproduce the observed experimental behavior, i.e., evolution of the field dependence of the complex impedance with annealing and the asymmetrical field dependence under a dc biased electrical current.
Stress and vibraton analyses of anisotropic shells of revolution
Noor, Ahmed K.; Peters, Jeanne M.
1988-01-01
An efficient computational strategy is presented for reducing the cost of the stress and free vibration analyses of laminated anisotropic shells of revolution. The analytical formulation is based on a form of the Sanders-Budiansky shell theory including the effects of both the transverse shear deformation and the laminated anisotropic material response. The fundamental unknowns consist of the eight strain components, the eight stress resultants and the five generalized displacements of the shell. Each of the shell variables is expressed in terms of trigonometric functions (Fourier series) in the circumferential co-ordinate, and a three-field mixed finite element model is used for the discretization in the meridional direction. The shell response associated with a range of Fourier harmonics is approximated by a linear combination of a few global approximation vectors, which are generated at a particular value of the Fourier harmonic, within that range. The full equations of the finite element model are solved for only a single Fourier harmonic, and the response corresponding to the other Fourier harmonics is generated using a reduced system of equations with considerably fewer degrees of freedom.
Energy Technology Data Exchange (ETDEWEB)
Alcock, C; Alves, D; Axelrod, T; Becker, A; Bennett, D; Clement, C; Cook, K; Drake, A; Freeman, K; Geha, M; Griest, K; Lehner, M; Marshall, S; Minniti, D; Muzzin, A; Nelson, C; Peterson, B; Popowski, P; Pratt, M; Quinn, P; Rodgers, A; Rowe, J; Sutherland, W; Vandehei, T; Welch, D
2003-12-31
Shapes of RR Lyrae light curves can be described in terms of Fourier coefficients which past research has linked with physical characteristics such as luminosity, mass and temperature. Fourier coefficients have been derived for the V and R light curves of 785 overtone RR Lyrae variables in 16 MACHO fields near the bar of the LMC. In general, the Fourier phase differences {phi}{sub 21}, {phi}{sub 31} and {phi}{sub 41} increase and the amplitude ratio R{sub 21} decreases with increasing period. The coefficients for both the V and R magnitudes follow these patterns, but the phase differences for the R curves are on average slightly greater, and their amplitudes are about 20% smaller, than the ones for the V curves. The {phi}{sub 31} and R{sub 21} coefficients have been compared with those of the first overtone RR Lyrae variables in the Galactic globular clusters NGC 6441, M107, M5, M3, M2, {omega} Centauri and M68. The results indicate that many of the LMC variables have properties similar to the ones in M2, M3, M5 and the Oosterhoff type I variables in {omega} Cen, but they are different from the Oosterhoff type II variables in {omega} Cen. Equations derived from hydrodynamic pulsation models have been used to calculate the luminosity and temperature for the 330 bona fide first-overtone variables. The results indicate that they have Log L in the range 1.6 to 1.8 L{sub {center_dot}} and log T{sub eff} between 3.85 and 3.87. Based on these temperatures, a mean color excess E(V-R) = 0.08 mag, equivalent to E(B-V) = 0.14 mag, has been estimated for these 330 stars. The 80 M5-like variables (selected according to their location in the {phi}{sub 31} - log P plot) are used to determine an LMC distance. After correcting for the effects of extinction and crowding, a mean apparent magnitude < V{sub 0} > = 18.99 {+-} 0.02 (statistical) {+-} 0.16 (systematic) has been estimated for these 80 stars. Combining this with a mean absolute magnitude M{sub V} = 0.56 {+-} 0.06 for M5
Quantum Fourier Transform and Phase Estimation in Qudit System
Institute of Scientific and Technical Information of China (English)
CAO Ye; PENG Shi-Guo; ZHENG Chao; LONG Gui-Lu
2011-01-01
The quantum Fourier transform and quantum phase estimation are the key components for many quantum algorithms, such as order-finding, factoring, and etc.In this article, the general procedure of quantum Fourier transform and phase estimation are investigated for high dimensional case.They can be seen as subroutines in a main program run in a qudit quantum computer, and the quantum circuits are given.
Recognizing shipbuilding parts using artificial neural networks and Fourier descriptors
Sanders, David
2009-01-01
A pattern recognition system is described for recognizing shipbuilding parts using artificial neural networks and Fourier descriptors. The system uses shape contour information that is invariant of size, translation, and rotation. Fourier descriptors provide information, and the neural networks make decisions about the shapes. A brief review of the current state of the art is included, and results from testing show that the system distinguished between various shapes and proved to be a valid ...
CONVERGENCE OF LOGARITHMIC MEANS OF MULTIPLE WALSH-FOURIER SERIES
Institute of Scientific and Technical Information of China (English)
G. Gát; U. Goginava; G. Tkebuchava
2005-01-01
N(o)rlund logarithmic means of multiple Walsh-Fourier series acting from space L Ind -1 L ([0, 1) d ), d ≥1 into space weak - L1([0, 1)d) are studied. The maximal Orlicz space such that the N(o)rlund logarithmic means of multiple Walsh-Fourier series for the functions from this space converge in d-dimensional measure is found.
On multipliers of Fourier series in the Lorentz space
Ydyrys, Aizhan Zh.; Tleukhanova, Nazerke T.
2016-08-01
We study the multipliers of Fourier series on the Lorentz spaces, in particular, the sufficient conditions for a sequence of complex numbers {λk}k∈Z in order to make it a multiplier of trigonometric Fourier series of space Lp,r [0; 1] in the Lq,r [0; 1]. In the paper there is a new multipliers theorem which is supplement of the well-known theorems, and given a counterexample.
Solving Nonlinear Time Delay Control Systems by Fourier series
Directory of Open Access Journals (Sweden)
Mohammad Hadi Farahi
2014-06-01
Full Text Available In this paper we present a method to find the solution of time-delay optimal control systems using Fourier series. The method is based upon expanding various time functions in the system as their truncated Fourier series. Operational matrices of integration and delay are presented and are utilized to reduce the solution of time-delay control systems to the solution of algebraic equations. Illustrative examples are included to demonstrate the validity and applicability of the technique.
Simple optical setup implementation for digital Fourier transform holography
Energy Technology Data Exchange (ETDEWEB)
De Oliveira, G N [Pos-graduacao em Engenharia Mecanica, TEM/PGMEC, Universidade Federal Fluminense, Rua Passo da Patria, 156, Niteroi, R.J., Cep.: 24.210-240 (Brazil); Rodrigues, D M C; Dos Santos, P A M, E-mail: pams@if.uff.br [Instituto de Fisica, Laboratorio de Optica Nao-linear e Aplicada, Universidade Federal Fluminense, Av. Gal. Nilton Tavares de Souza, s/n, Gragoata, Niteroi, R.J., Cep.:24.210-346 (Brazil)
2011-01-01
In the present work a simple implementation of Digital Fourier Transform Holography (DFTH) setup is discussed. This is obtained making a very simple modification in the classical setup arquiteture of the Fourier Transform holography. It is also demonstrated the easy and practical viability of the setup in an interferometric application for mechanical parameters determination. The work is also proposed as an interesting advanced introductory training for graduated students in digital holography.
Fractally Fourier decimated homogeneous turbulent shear flow in noninteger dimensions
Fathali, Mani; Khoei, Saber
2017-02-01
Time evolution of the fully resolved incompressible homogeneous turbulent shear flow in noninteger Fourier dimensions is numerically investigated. The Fourier dimension of the flow field is extended from the integer value 3 to the noninteger values by projecting the Navier-Stokes equation on the fractal set of the active Fourier modes with dimensions 2.7 ≤d ≤3.0 . The results of this study revealed that the dynamics of both large and small scale structures are nontrivially influenced by changing the Fourier dimension d . While both turbulent production and dissipation are significantly hampered as d decreases, the evolution of their ratio is almost independent of the Fourier dimension. The mechanism of the energy distribution among different spatial directions is also impeded by decreasing d . Due to this deficient energy distribution, turbulent field shows a higher level of the large-scale anisotropy in lower Fourier dimensions. In addition, the persistence of the vortex stretching mechanism and the forward spectral energy transfer, which are three-dimensional turbulence characteristics, are examined at changing d , from the standard case d =3.0 to the strongly decimated flow field for d =2.7 . As the Fourier dimension decreases, these forward energy transfer mechanisms are strongly suppressed, which in turn reduces both the small-scale intermittency and the deviation from Gaussianity. Besides the energy exchange intensity, the variations of d considerably modify the relative weights of local to nonlocal triadic interactions. It is found that the contribution of the nonlocal triads to the total turbulent kinetic energy exchange increases as the Fourier dimension increases.
Fourier transform spectroscopy in the visible and ultraviolet range.
Luc, P; Gerstenkorn, S
1978-05-01
In cases where the photon noise is the limiting factor, the multiplex gain is not always conserved; however the throughput (Jacquinot's advantage) is not affected. Therefore extension of Fourier transform spectroscopy to higher frequencies has great possibilities. Studies at high resolution, both in emission and in absorption, show that the performance achieved by Fourier transform spectroscopy in the visible and uv range is comparable with that reached in the ir.
A discrete Fourier transform for virtual memory machines
Galant, David C.
1992-01-01
An algebraic theory of the Discrete Fourier Transform is developed in great detail. Examination of the details of the theory leads to a computationally efficient fast Fourier transform for the use on computers with virtual memory. Such an algorithm is of great use on modern desktop machines. A FORTRAN coded version of the algorithm is given for the case when the sequence of numbers to be transformed is a power of two.
Fractally Fourier decimated homogeneous turbulent shear flow in noninteger dimensions.
Fathali, Mani; Khoei, Saber
2017-02-01
Time evolution of the fully resolved incompressible homogeneous turbulent shear flow in noninteger Fourier dimensions is numerically investigated. The Fourier dimension of the flow field is extended from the integer value 3 to the noninteger values by projecting the Navier-Stokes equation on the fractal set of the active Fourier modes with dimensions 2.7≤d≤3.0. The results of this study revealed that the dynamics of both large and small scale structures are nontrivially influenced by changing the Fourier dimension d. While both turbulent production and dissipation are significantly hampered as d decreases, the evolution of their ratio is almost independent of the Fourier dimension. The mechanism of the energy distribution among different spatial directions is also impeded by decreasing d. Due to this deficient energy distribution, turbulent field shows a higher level of the large-scale anisotropy in lower Fourier dimensions. In addition, the persistence of the vortex stretching mechanism and the forward spectral energy transfer, which are three-dimensional turbulence characteristics, are examined at changing d, from the standard case d=3.0 to the strongly decimated flow field for d=2.7. As the Fourier dimension decreases, these forward energy transfer mechanisms are strongly suppressed, which in turn reduces both the small-scale intermittency and the deviation from Gaussianity. Besides the energy exchange intensity, the variations of d considerably modify the relative weights of local to nonlocal triadic interactions. It is found that the contribution of the nonlocal triads to the total turbulent kinetic energy exchange increases as the Fourier dimension increases.
dos Santos, João Henrique Z; Butler, Ian S; Daga, Vasiliki; Hadjikakou, Sotiris; Hadjiliadis, Nick
2002-10-01
The pressure dependences of the Fourier transform micro-Raman spectra of four heterocyclic thioamides [[(bztzdtH)I2] x I2] (1) (bztzdtH = benzothiazole-2-thione), [(bztzdtH)I2] (2), [[(tzdtH)2I+] x I3- x 2I2] (3) (tzdtH = thiazoline-2-thione), and [[(bzimtH)I2]2 x I2 x 2H2O] (4) (bzimtH = benzimidazole-2-thione) have been studied between ambient pressure and 50 kbar. For 1, generation of I3- ions through disproportionation reactions is evident as the pressure is increased. There are empirical linear correlations between the frequency and (I-I) bond length and the applied pressure. The iodine adduct of thioamide 2 is more sensitive to pressure when compared to the 1 or 4 iodine adducts. This difference in behavior may be attributed to differences in crystal structures or to a lower I-I bond order. Monitoring of other vibrational transitions of the thiomide structure reveals several less important pressure dependences.
Qu, Zhengxian; Wang, Dadong; Ma, Yanbao
2017-01-01
An appropriate heat conduction model is indispensable for experimental data analysis in nanothermometry in order to extract parameters of interests and to achieve a fundamental understanding of phonon-mediated heat transfer in nanostructures and across interfaces. Recently, nanoscale periodic metallic gratings are used as a group of distributed heaters as well as transducers in nanothermometry. However, in this technique, there are coupled hotspot-size-dependent effective thermal conductivity (ETC) and hotspot-size-dependent thermal interface resistivity, which posts a challenge for experimental data analysis using Fourier's law that fails to extract both ETC and thermal interface resistivity simultaneously. To overcome this challenge, a novel two-parameter nondiffusive heat conduction (TPHC) model, which has been successfully applied to data analysis in different types of pump-probe experiments, is applied to analyze laser-induced nondiffusive heat transfer in nanoscale metallic grating experiments. Since the hotspot-size-dependent ETC is automatically captured by the TPHC model, the hotspot-size-dependent interface resistivity becomes the only parameter to be determined from experiments through data fitting. Thus, the hotspot-size-dependent thermal interface resistivity can be determined from experiments without the impact from the hotspot-size-dependent ETC. Currently, there is a lack of a criterion to predict when Fourier's law breaks down in nanoscale heat transfer. To fill this gap, a criterion based the TPHC model is identified to predict the valid range of Fourier's law, which is validated in both theoretical analyses and nanoscale metallic grating experiments.
Analysis of tokamak plasma confinement modes using the fast Fourier transformation
Indian Academy of Sciences (India)
S R MIRMOEINI; A SALAR ELAHI; M GHORANNEVISS
2016-11-01
The Fourier analysis is a satisfactory technique for detecting plasma confinement modes in tokamaks. The confinement mode of tokamak plasma was analysed using the fast Fourier transformation (FFT). For this purpose, we used the data of Mirnov coils that is one of the identifying tools in the IR-T1 tokamak, with and without external field (electric biasing), and then compared it with each other. After the Fourier analysis of Mirnov coil data, the diagram of power spectrum density was depicted in different angles of Mirnov coils in the ‘presenceof external field’ as well as in the ‘absence of external field’. The power spectrum density (PSD) interprets the manner of power distribution of a signal with frequency. In this article, the number of plasma modes and the safety factor $q$ were obtained by using the mode number of $q = m/n$ ($m$ is the mode number). The maximum MHD activity was obtained in 30–35 kHz frequency, using the density of the energy spectrum. In addition, the number of different modes across 0–35 ms time was compared with each other in the presence and absence of theexternal field.
Dynamic measurement of deformation using Fourier transform digital holographic interferometry
Gao, Xinya; Wu, Sijin; Yang, Lianxiang
2013-10-01
Digital holographic interferometry (DHI) is a well-established optical technique for measurement of nano-scale deformations. It has become more and more important due to the rapid development of applications in aerospace engineering and biomedicine. Traditionally, phase shift technique is used to quantitatively measure the deformations in DHI. However, it cannot be applied in dynamic measurement. Fourier transform phase extraction method, which can determine the phase distribution from only a single hologram, becomes a promising method to extract transient phases in DHI. This paper introduces a digital holographic interferometric system based on 2D Fourier transform phase extraction method, with which deformations of objects can be measured quickly. In the optical setup, the object beam strikes a CCD via a lens and aperture, and the reference beam is projected on the CCD through a single-mode fiber. A small inclination angle between the diverging reference beam and optical axial is introduced in order to physically separate the Fourier components in frequency domain. Phase maps are then obtained by the utilization of Fourier transform and windowed inverse Fourier transform. The capability of the Fourier transform DHI is discussed by theoretical discussion as well as experiments.
Accurate estimators of correlation functions in Fourier space
Sefusatti, E.; Crocce, M.; Scoccimarro, R.; Couchman, H. M. P.
2016-08-01
Efficient estimators of Fourier-space statistics for large number of objects rely on fast Fourier transforms (FFTs), which are affected by aliasing from unresolved small-scale modes due to the finite FFT grid. Aliasing takes the form of a sum over images, each of them corresponding to the Fourier content displaced by increasing multiples of the sampling frequency of the grid. These spurious contributions limit the accuracy in the estimation of Fourier-space statistics, and are typically ameliorated by simultaneously increasing grid size and discarding high-frequency modes. This results in inefficient estimates for e.g. the power spectrum when desired systematic biases are well under per cent level. We show that using interlaced grids removes odd images, which include the dominant contribution to aliasing. In addition, we discuss the choice of interpolation kernel used to define density perturbations on the FFT grid and demonstrate that using higher order interpolation kernels than the standard Cloud-In-Cell algorithm results in significant reduction of the remaining images. We show that combining fourth-order interpolation with interlacing gives very accurate Fourier amplitudes and phases of density perturbations. This results in power spectrum and bispectrum estimates that have systematic biases below 0.01 per cent all the way to the Nyquist frequency of the grid, thus maximizing the use of unbiased Fourier coefficients for a given grid size and greatly reducing systematics for applications to large cosmological data sets.