125 resultados para Fourier series.
Resumo:
A bit level systolic array system is proposed for the Winograd Fourier transform algorithm. The design uses bit-serial arithmetic and, in common with other systolic arrays, features nearest-neighbor interconnections, regularity and high throughput. The short interconnections in this method contrast favorably with the long interconnections between butterflies required in the FFT. The structure is well suited to VLSI implementations. It is demonstrated how long transforms can be implemented with components designed to perform a short length transform. These components build into longer transforms preserving the regularity and structure of the short length transform design.
Resumo:
Details of a new low power fast Fourier transform (FFT) processor for use in digital television applications are presented. This has been fabricated using a 0.6-µm CMOS technology and can perform a 64 point complex forward or inverse FFT on real-time video at up to 18 Megasamples per second. It comprises 0.5 million transistors in a die area of 7.8 × 8 mm and dissipates 1 W. The chip design is based on a novel VLSI architecture which has been derived from a first principles factorization of the discrete Fourier transform (DFT) matrix and tailored to a direct silicon implementation.
Resumo:
A bit-level systolic array system is proposed for the Winograd Fourier transform algorithm. The design uses bit-serial arithmetic and, in common with other systolic arrays, features nearest neighbor interconnections, regularity, and high throughput. The short interconnections in this method contrast favorably with the long interconnections between butterflies required in the FFT. The structure is well suited to VLSI implementations. It is demonstrated how long transforms can be implemented with components designed to perform short-length transforms. These components build into longer transforms, preserving the regularity and structure of the short-length transform design.
Resumo:
In this study, the adsorption characteristics of two series of oxygen and nitrogen functionalized activated carbons were investigated. These series were a low nitrogen content(similar to 1 wt % daf) carbon series derived from coconut shell and a high nitrogen content (similar to 8 wt % daf) carbon series derived from polyacrylonitrile. In both series, the oxygen contents were varied over the range similar to 2-22 wt % daf. The porous structures of the functionalized activated carbons were characterized using N-2 (77 K) and CO2 (273 K) adsorption. Only minor changes in the porous structure were observed in both series. This allowed the effect of changes in functional group concentrations on metal ion adsorption to be studied without major influences due to differences in porous structure characteristics. The surface group characteristics were examined by Fourier transform infrared (FTIR) spectroscopy, acid/base titrations, and measurement of the point of zero charge (pH(PZC)). The adsorption of aqueous metal ion species, M2+(aq), on acidic oxygen functional group sites mainly involves an ion exchange mechanism. The ratios of protons displaced to the amount of M2+(aq) metal species adsorbed have a linear relationship for the carbons with pH(PZC) <= 4.15. Hydrolysis of metal species in solution may affect the adsorption of metal ion species and displacement of protons. In the case of basic carbons, both protons and metal ions are adsorbed on the carbons. The complex nature of competitive adsorption between the proton and metal ion species and the amphoteric character of carbon surfaces are discussed in relation to the mechanism of adsorption.
Resumo:
The problem of model selection of a univariate long memory time series is investigated once a semi parametric estimator for the long memory parameter has been used. Standard information criteria are not consistent in this case. A Modified Information Criterion (MIC) that overcomes these difficulties is introduced and proofs that show its asymptotic validity are provided. The results are general and cover a wide range of short memory processes. Simulation evidence compares the new and existing methodologies and empirical applications in monthly inflation and daily realized volatility are presented.
Resumo:
In this paper, we characterize surjective completely bounded disjointness preserving linear operators on Fourier algebras of locally compact amenable groups. We show that such operators are given by weighted homomorphisms induced by piecewise affine proper maps. © 2011 Elsevier Inc.
Transnational Fantômas: The Influence of Feuillade’s Series on International Cinema during the 1910s
Resumo:
The influence of Fantômas novels and films on global popular culture is widely acknowledged. From the 1915 Spanish musical "Cine-fantomas" to the 1960s Italian comic book series "Diabolik," "Kriminal" and "Satanik," from Turkish B-movies such as "Fantoma Istanbulda Bulusalim" (dir. Natuk Baytan, 1967) to Julio Cortazar’s anti-imperialist pamphlet "Fantômas contra los vampiros multinacionales" (1975), Pierre Souvestre and Marcel Allain’s original literary series have engendered uncountable translations, adaptations, imitations and plagiarisms that have spread the character’s fame worldwide since its first appearance in 1911.
By focusing on the influence of Louis Feuillade’s film adaptations during the first decade of Fantômas’ long history as a transnational and transmedia icon, this paper aims to contribute to the growing interdisciplinary field that deals with the history of the supranational cultural sphere created by modern media culture. As a sort of archaeology of contemporary cultural globalization, this form of study intends to enrich previous historical surveys that had only taken into consideration specific national contexts. Moreover, it might also rebalance certain “colonizing” accounts that overemphasize the role of the cultural superpowers such as France, the UK or the US, often forgetting the appropriation of the products of international popular culture to be found in other countries. Therefore, this paper examines the transnational circulation of Fantômas films and, in particular, the creative processes engendered outside of France their origin country. As a controversial character and a central player in the relationship between cinema and literature in the crucial years when the feature and serial film boosted and legitimized the film industry, Fantômas represents an exemplary case study to discuss the cross-cultural and cross-media dynamics engendered by popular fiction.
Resumo:
In this paper, the design constraints that are required for a Rotman lens to realize discrete Fourier transform (DFT) amplitude and phase functionality are derived. A Fourier Rotman lens has been designed, fabricated and validated. The amplitude and phase response and the array pattern based on the CST™ results are validated with the theoretical DFT results. To the best of the authors' knowledge, this is the first Fourier Rotman lens to be fabricated and validated. The solution provided replaces multilayer Butler matrix solutions with a simple single layer microstrip technology.
Resumo:
The autonomous pathway functions to promote flowering in Arabidopsis by limiting the accumulation of the floral repressor FLOWERING LOCUS C (FLC). Within this pathway FCA is a plant-specific, nuclear RNA-binding protein, which interacts with FY, a highly conserved eukaryotic polyadenylation factor. FCA and FY function to control polyadenylation site choice during processing of the FCA transcript. Null mutations in the yeast FY homologue Pfs2p are lethal. This raises the question as to whether these essential RNA processing functions are conserved in plants. Characterisation of an allelic series of fy mutations reveals that null alleles are embryo lethal. Furthermore, silencing of FY, but not FCA, is deleterious to growth in Nicotiana. The late-flowering fy alleles are hypomorphic and indicate a requirement for both intact FY WD repeats and the C-terminal domain in repression of FLC. The FY C-terminal domain binds FCA and in vitro assays demonstrate a requirement for both C-terminal FY-PPLPP repeats during this interaction. The expression domain of FY supports its roles in essential and flowering-time functions. Hence, FY may mediate both regulated and constitutive RNA 3'-end processing.
Resumo:
Malone, C. and N. Bernard, Stonehenge. 2004, New York, Oxford University Press.
Resumo:
White household paints are commonly encountered as evidence in the forensic laboratory but they often cannot be readily distinguished by color alone so Fourier transform infrared (FT-IR) microscopy is used since it can sometimes discriminate between paints prepared with different organic resins. Here we report the first comparative study of FT-IR and Raman spectroscopy for forensic analysis of white paint. Both techniques allowed the 51 white paint samples in the study to be classified by inspection as either belonging to distinct groups or as unique samples. FT-IR gave five groups and four unique samples; Raman gave seven groups and six unique samples. The basis for this discrimination was the type of resin and/ or inorganic pigments/extenders present. Although this allowed approximately half of the white paints to be distinguished by inspection, the other half were all based on a similar resin and did not contain the distinctive modifiers/pigments and extenders that allowed the other samples to be identified. The experimental uncertainty in the relative band intensities measured using FT-IR was similar to the variation within this large group, so no further discrimination was possible. However, the variation in the Raman spectra was larger than the uncertainty, which allowed the large group to be divided into three subgroups and four distinct spectra, based on relative band intensities. The combination of increased discrimination and higher sample throughput means that the Raman method is superior to FT-IR for samples of this type. © 2005 Society for Applied Spectroscopy.