Speed, power, area, and latency tradeoffs in adaptive FIR filteringfor PRML read channels

In this paper, we describe area and power reduction techniques for a low-latency adaptive finite-impulse response filter for magnetic recording read channel applications. Various techniques are used to reduce area and power dissipation while speed and latency remain as the main performance criteria for the target application. The proposed parallel transposed direct form architecture operates on real-time input data samples and employs a fast, low-area multiplier based on selection of radix-8 premultiplied coefficients in conjunction with one-hot encoded bus leading to a very compact layout and reduced power dissipation. Area, speed, and power comparisons with other low-power implementation options are also shown. The proposed filter has been fabricated using a 0.18-μm L-effective CMOS technology and operates at 550 MSamples/s. Trading off filter latency to improve speed is also discussed     

A 550-MSample/s 8-Tap FIR digital filter for magnetic recordingread channels

An area-efficient low-power and low-latency 550-MSample/s FIR filter for magnetic recording read channel applications is presented. A parallel direct type II architecture operates on real-time deinterleaved (even and odd) input data samples and employs a fast low-area multiplier based on selection of radix-8 premultiplied coefficients in conjunction with one-hot encoded bus leading to a very compact layout and reduced power dissipation. The chip has been fabricated using a 0.18-μm L-effective CMOS technology and is currently being used in commercial applications     

Testing software components for integration: a survey of issues and techniques

Component‐based development has emerged as a system engineering approach that promises rapid software development with fewer resources. Yet, improved reuse and reduced cost benefits from software components can only be achieved in practice if the components provide reliable services, thereby rendering component analysis and testing a key activity. This paper discusses various issues that can arise in component testing by the component user at the stage of its integration within the target system. The crucial problem is the lack of information for analysis and testing of externally developed components. Several testing techniques for component integration have recently been proposed. These techniques are surveyed here and classified according to a proposed set of relevant attributes. The paper thus provides a comprehensive overview which can be useful as introductory reading for newcomers in this research field, as well as to stimulate further investigation. Copyright © 2006 John Wiley & Sons, Ltd.     

Impairment related to blood drug concentrations of zopiclone and zolpidem compared to alcohol in apprehended drivers

Background

About 3-7% of the adult population receives prescribed hypnotics. The benzodiazepine-like hypnotics, zopiclone and zolpidem, are the most commonly prescribed and may cause traffic-relevant impairment similar to that found for benzodiazepines. We investigated the relationship between blood zopiclone and zolpidem concentrations and driving impairment, as assessed by the clinical test for impairment. We compared these groups of drivers to a group suspected of alcohol-related impairment.

Methods

Blood samples from suspected impaired drivers during 2000-2007, screened for approximately 25 possible impairing drugs with only one single drug detected, were studied in relation to the assessment of impairment. The 79 zopiclone positive drivers, the 43 zolpidem positive drivers, and the 3480 alcohol positive drivers were divided into groups depending on blood drug concentrations.

Results/discussion

The proportion of drivers judged as impaired tended to increase the higher the blood zopiclone concentrations. Such a positive relationship was not found for zolpidem. For alcohol the proportion of impaired drivers was significantly related to blood alcohol concentrations (BACs). There were few drivers with low zopiclone or zolpidem concentrations included, which may have obscured any positive significant relationship. The percentage of impaired drivers among drivers with blood zopiclone concentrations above 130 μg/l roughly corresponded to the percentage of impaired drivers among drivers with BACs higher than 0.1%.     

Computation of the stress intensity factors of sharp notched plates by the fractal‐like finite element method

The fractal‐like finite element method (FFEM) is an accurate and efficient method to compute the stress intensity factors (SIFs) of different crack configurations. In the FFEM, the cracked/notched body is divided into singular and regular regions; both regions are modelled using conventional finite elements. A self‐similar fractal mesh of an ‘infinite’ number of conventional finite elements is used to model the singular region. The corresponding large number of local variables in the singular region around the crack tip is transformed to a small set of global co‐ordinates after performing a global transformation by using global interpolation functions. In this paper, we extend this method to analyse the singularity problems of sharp notched plates. The exact stress and displacement fields of a plate with a notch of general angle are derived for plane‐stress/strain conditions. These exact analytical solutions which are eigenfunction expansion series are used to perform the global transformation and to determine the SIFs. The use of the global interpolation functions reduces the computational cost significantly and neither post‐processing technique to extract SIFs nor special singular elements to model the singular region are needed. The numerical examples demonstrate the accuracy and efficiency of the FFEM for sharp notched problems. Copyright © 2008 John Wiley & Sons, Ltd.     

Enhancement of electrical resistivity of Sr0.5Ba0.5Fe12O19 nanomaterials by doping with lanthanum and nickel

From the viewpoint of electronic and telecommunication devices, the electrical resistivity is required to be high to curb the eddy current losses for efficient performance at high frequencies. In the present work, Sr_0.5Ba_0.5Fe₁₂O₁₉ hexaferrite has been doped with a binary mixture of lanthanum and nickel using chemical co-precipitation method of synthesis. The crystallite size of the synthesized samples is estimated in the range of 36–58 nm and their structural analyses have confirmed a single magnetoplumbite phase. The magnitude of the dc-electrical resistivity is enhanced, by almost 100 times, but Curie temperature (T_C) is reduced by doping with La–Ni, which has been explained on the basis of the exchange interactions. In addition, the doped samples exhibit very low dielectric constant (έ = 11–13) and low dielectric loss tangent (tan δ = 0.07–0.10) determined at a frequency of 1 MHz. These characteristics may be suitable for their potential application in electromagnetic attenuation materials and microwave devices.     

Heavy metal accumulation in different varieties of wheat (Triticum aestivum L.) grown in soil amended with domestic sewage sludge

The concentrations of heavy metals (HMs) in plants served to indicate the metal contamination status of the site, and also revealed the abilities of various plant species to take up and accumulate them from the soil dressed with sewage sludge. A study to comprehend the mobility and transport of HMs from soil and soil amended with untreated sewage sludge to different newly breaded varieties of wheat (Anmol, TJ-83, Abadgar and Mehran-89) in Pakistan. A pot-culture experiment was conducted to study the transfer of HMs to wheat grains, grown in soil (control) and soil amended with sewage sludge (test samples). The total and ethylenediaminetetraaceticacid (EDTA)-extractable HMs in agricultural soil and soil amended with domestic sewage sludge (SDWS) and wheat grains were analysed by flame atomic absorption spectrometer/electrothermal atomic absorption spectrometer, prior to microwave-assisted wet acid digestion method. The edible part of wheat plants (grains) from test samples presented high concentration of all HMs understudy (mgkg(-1)). Significant correlations were found between metals in exchangeable fractions of soil and SDWS, with total metals in control and test samples of wheat grains. The bio-concentration factors of all HMs were high in grains of two wheat varieties, TJ-83 and Mehran-89, as compared to other varieties, Anmol and Abadgar grown in the same agricultural plots.     

Determination of optimum operating conditions of carmine decoloration by UV/H2O2 using response surface methodology

In this study, the photolytic decoloration of carmine (C.I. Natural Red 4) via UV radiation in the presence of H2O2 was optimized using response surface methodology (RSM). According to analysis of variance (ANOVA) results, the proposed model can be used to navigate the design space. It was found that the response of carmine degradation is very sensitive to the independent factors of carmine concentration, H2O2 concentration, pH and reaction time. The proposed model for D-optimal design fitted very well with the experimental data with R2 and R(adj)2 correlation coefficients of 0.998 and 0.997, respectively.     

Vibration characteristics of FGM circular cylindrical shells using wave propagation approach

In this paper, the wave propagation approach is employed to study the vibration characteristics of functionally graded material circular cylindrical shells. Axial modal dependence is approximated by exponential functions. This is a very simple and easily applicable technique. This avoids a large amount of algebraic manipulations. A theoretical analysis of shell natural frequencies are conducted for various boundary conditions. Validity and accuracy of the present method are confirmed by comparing the present results with those available in the literature. A good agreement is observed between the two sets of the results.