Minimax Approximation of Representation Coefficients From Generalized Samples

Many sources of information are of analog or continuous-time nature. However, digital signal processing applications rely on discrete data. We consider the problem of approximating L₂ inner products, i.e., representation coefficients of a continuous-time signal, from its generalized samples. Adopting a robust approach, we process these generalized samples in a minimax optimal sense. Specifically, we minimize the worst approximation error of the desired representation coefficients by proper processing of the given sample sequence. We then extend our results to criteria which incorporate smoothness constraints on the unknown function. Finally, we compare our methods with the piecewise-constant approximation technique, commonly used for this problem, and discuss the possible improvements by the suggested schemes.     

Approximate string matching with address bit errors

A string S∈Σ^m$S\in {\Sigma }^m$ can be viewed as a set of pairs S={(_σi,i):i∈{0,…,m−1}}$S=\{({\sigma }_i,i):i\in \{0,\dots ,m-1\}\}$. We consider approximate pattern matching problems arising from the setting where errors are introduced to the location component (i$i$), rather than the more traditional setting, where errors are introduced into the content itself (_σi${\sigma }_i$). In this paper, we consider the case where bits of i$i$ may be erroneously flipped, either in a consistent or transient manner. We formally define the corresponding approximate pattern matching problems, and provide efficient algorithms for their resolution, while introducing some novel techniques.     

Investigation of the dominant point defects in tetragonal YBa2Cu3Ox at elevated temperatures

The manner in which oxygen is incorporated into YBa₂Cu₃O _x (YBCO) at 800°C for values ofx close to 6 is shown to be in the form of neutral oxygen interstitials, O _i ^x . The experimental data on which this conclusion is based are obtained from measurements of oxygen partial pressure,P(O₂), as a function of compositionx and temperatureT (5.99x 6.35, 825T1120 K). The data are obtained by a solid-state electrochemical method. Other conclusions of this study include: (a) O _i ^x are noninteracting forx 6. (b) The stoichiometric composition of YBCO isx 6.0. (c) The reaction enthalpy of oxidation is 179 kJ/mol O₂. (d) The Fermi level changes by –0.2 eV asx increases from 6.05 to 6.35.     

Mandarin fruit quality: a review

During the last decade, there has been a continuous rise in consumption and global marketing of fresh, easy‐to‐peel mandarins, with current annual production of nearly 29 million tons. Nevertheless, most of the existing knowledge on quality traits of citrus fruit comes from research conducted on oranges and grapefruit, which are the main products for the citrus juice manufacturing industry; relatively little is yet known regarding the unique fruit quality traits of mandarins, nor about the great diversity in these traits among the various natural sub‐groups and varieties of mandarins. In the present review we discuss the physiological, biochemical, and molecular factors governing key fruit quality attributes of mandarins, including fruit colour, size and shape, ease of peeling, seedlessness, flavour, and nutritional quality. Fruit colour, size, and shape contribute to external appearance; peelability and seedlessness to ease of consumption; and flavour and nutritional quality to internal quality. © 2017 Society of Chemical Industry     

Cover Image,Volume 98, Issue 1

The cover image, by Livnat Goldenberg et al., is based on the Review Mandarin fruit quality: a review, DOI: 10.1002/jsfa.8495 .

     

Mass production of nanofibre assemblies by electrostatic spinning

Electrospinning is a well‐established and intensively investigated methodology, and is currently the only known technique that can fabricate continuous nanofibres. The major challenge associated with electrospinning is its production rate, compared with that of conventional fibre spinning. However, the understanding of the scale‐up possibility of the electrospinning process is still in its infancy. Substantial up‐scaling of electrospinning may pave the way for applications of nanofibre assemblies (i.e. yarns) not accessible otherwise in conventional textile processes, such as weaving, knitting and braiding. Here we summarize recent advances regarding the enhancement of electrospinning throughput with special emphasis on multiple jets from multi‐needles and the free surface of polymer solutions. Copyright © 2009 Society of Chemical Industry     

FIR system identification using fourth-order cumulants withapplication to channel equalization

Three algorithms for finite impulse response (FIR) system identification from output measurements, using fourth-order cumulants, are described. The impulse response is assumed to be complex, and the input is a complex independent and identically distributed (i.i.d) non-Gaussian sequence. The algorithms are based on a certain low-rank matrix constructed from the output cumulants. An application of the algorithms to blind equalization of digital communication channels is discussed and illustrated by some examples     

The generalized Gabor scheme of image representation in biologicaland machine vision

A scheme suitable for visual information representation in a combined frequency-position space is investigated through image decomposition into a finite set of two-dimensional Gabor elementary functions (GEF). The scheme is generalized to account for the position-dependent Gabor-sampling rate, oversampling, logarithmic frequency scaling and phase-quantization characteristic of the visual system. Comparison of reconstructed signal highlights the advantages of the generalized Gabor scheme in coding typical bandlimited images. It is shown that there exists a tradeoff between the number of frequency components used per position and the number of such clusters (sampling rate) utilized along the spatial coordinate