Fourier transform communication system

Salz, J.; Weinstein, Stephen B.

doi:10.1145/800165.805240

Cited by 40 publications

(19 citation statements)

References 4 publications

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“…Fields of application are wide in range with examples from -Physics (optics, acoustics and diffraction), Signal Processing and Communication Systems, Image Processing, Astronomy, and DNA sequence analysis, amongst others, (A'Hearn et al, 1974;Goodman, 2005;Salz & Weinstein, 1969). Early work using Fourier technique in DNA pattern recognition was carried out by Tiwari et al In this method, small sequences from bacteria were first converted into four distinct sets of binary sequences, (each corresponding to location of a nucleotide), then analysed by applying Fourier.…”

Section: Methods To Analyse Dna Patternsmentioning

confidence: 99%

Modelling DNA Methylation Dynamics

Raghavan¹,

Ruskin²

2012

DNA Methylation - From Genomics to Technology

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Ireland Introduction"Epigenetics" as introduced by Conrad Waddington in 1946, is defined as a set of interactions between genes and the surrounding environment, which determines the phenotype or physical traits in an organism, (Murrell et al., 2005;Waddington, 1942). Initial research focused on genomic regions such as heterochromatin and euchromatin based on dense and relatively loose DNA packing, since these were known to contain inactive and active genes respectively, (Yasuhara et al., 2005). Subsequently, key roles of DNA methylation, Histone Modifications and other assistive proteins such as Methyl Binding Proteins (MBP) during gene expression and suppression were identified, (Baylin & Ohm, 2006;Jenuwein & Allis, 2001). An emergent and persistent view that every epigenetic event affects another, to strengthen or suppress gene expression has made this an active field of research. DNA methylation refers to the modification of DNA by addition of a methyl group to the cytosine base, and is the most stable, heritable and well conserved epigenetic change. It is introduced and maintained, (Riggs & Xiong, 2004;Ushijima et al., 2003) by an enzyme family called DNA Methyl Transferases (DNMT), (Doerfler et al., 1990). Methyl-Cytosine or "mC", often referred to as the fifth type of nucleotide plays an extremely important role in gene expression and other cellular activities. Although DM is defined a simple molecular modification, its effect, can range from altering the state of a single gene to controlling a whole section of chromosome in the human genome.The human genome is largely made of complex sequences evolved over time due to replication, mutations and insertion of foreign DNA. Based on the nucleotide distribution and functional significance, the genome has been categorized into different block of sequences, namely genes or coding and non-coding regions. A special type of sequence located near genes, in relation to spread of DNA methylation and dinucleotide frequencies are the CpG islands 1 . These islands are mostly found near the promoters, (5'end), of genes and their methylation levels are closely monitored to investigate the spread of Cancer. Useful insight on epigenetic mechanisms may be found from analysing the DNA sequence patterns or the genotype of the organism, (Gertz et al., 2011;Glass et al., 2004;Segal & Widom, 2009). Since more than 90% of DM occurs in CG dinucleotides, , knowledge of the distribution and location of CG can be utilized to understand the biological 1 DNA sequences are defined and classified as CpG islands if , (a) length of that DNA sequence >200 bp, (b) Total amount of Guanine and Cytosine nucleotides >50%, and, (c) the observed/expected ratio of CG dinucleotides for that given length of sequence, >60%, (Takai & Jones, 2002)

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Section: Methods To Analyse Dna Patternsmentioning

confidence: 99%

Modelling DNA Methylation Dynamics

Raghavan¹,

Ruskin²

2012

DNA Methylation - From Genomics to Technology

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“…However, this algorithm requires at least three modules of the Inverse Discrete Fourier Transform (IDFT) of length of double the number of carriers and pre-processing in the form of rotations (Bailey and Swarztrauber, 1991). In contrast, OFDM signal is efficiently generated with a single IDFT (Salz and Weinstein, 1969;Weinstein and Ebert, 1971). In this study we propose simple IDFT implementations to generate signals with fractional frequency spacing.…”

Section: Introductionmentioning

confidence: 99%

Inverse Discrete Fourier Transform-Discrete Fourier Transform Techniques for Generating and Receiving Spectrally Efficient Frequency Division Multiplexing Signals

Idarwazeh¹

2011

American Journal of Engineering and Applied Sciences

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Problem statement: Spectrally Efficient Frequency Division Multiplexing (SEFDM) system promises bandwidth savings by multiplexing overlapped non-orthogonal sub-carriers. However, the loss of orthogonality results in increasing the complexity of generation and detection of the signal. In this work, we propose simple framework for the generation of the SEFDM signal based on the Inverse Discrete Fourier Transform (IDFT). Approach: This study further proposes the use of the Discrete Fourier Transform (DFT) as the receiver front end, specifically for extracting the statistics of the signal needed for recovering the transmitted signal. The proposed transmitter designs employ similar building blocks as Orthogonal Frequency Division Multiplexing (OFDM) based systems, hence, would facilitate an easy migration and/or coexistence with OFDMon the transmitter side. Furthermore, the proposed framework may facilitate the IDFT design for any Frequency Division Multiplexed (FDM) signal with arbitrary sub-carriers spacing. Results and Conclusion: The equivalence of the IDFT generated signal and the modulators based signal is proved mathematically, nonetheless, numerical simulations were performed to verify that equivalence and to test for the performance of the digitally generated signal in AWGN channel. Numerical results confirmed the required spectrum compression and Bit Error Rate (BER) performance at a much reduced complexity.

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“…OFDM is a multicarrier transmission technique with a long history [7] which has recently gained prominence [8] due to the advances in digital signal processing techniques. OFDM provides the robustness against frequency selective fading without the need for powerful equalizers while fast Fourier transform (FFT) techniques can be exploited for efficient hardware implementations.…”

Section: Introductionmentioning

confidence: 99%

Fast simulation of OFDM systems over frequency selective fading channels

Wijesinghe

Gunawardana

Liyanapathirana

2010

2010 International Conference on Signal Processing and Communications (SPCOM)

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This paper illustrates the use of the Importance Sampling (IS) technique for efficient simulation of Orthogonal Frequency Division Multiplexing Systems operating over frequency selective fading channels with equalization. In order to achieve higher estimator variance reduction gains, the proper biasing procedure for time domain noise density function and the way of un-biasing the error count at the receiver in frequency domain are shown. Further, the optimum biasing parameters for conventional importance sampling (CIS) and improved importance sampling (IIS) methods are obtained. It is demonstrated, through simulations, that the proposed methods can provide extensive gains in estimator variance reduction and runtime saving compared to the conventional Monte-Carlo (MC) simulations.978-1-4244-7138-6/10/$26.00 ©2010 IEEE

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Fourier transform communication system

Cited by 40 publications

References 4 publications

Modelling DNA Methylation Dynamics

Modelling DNA Methylation Dynamics

Inverse Discrete Fourier Transform-Discrete Fourier Transform Techniques for Generating and Receiving Spectrally Efficient Frequency Division Multiplexing Signals

Fast simulation of OFDM systems over frequency selective fading channels

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