Cooley-Tukey-type algorithm for the Haar transform

It is shown that the Haar transform can be computed using a Cooley-Tukey-type algorithm that is implemented in 2(N?1) additions/subtractions. This algorithm is derived by relating the Haar transform to the modified Walsh-Hadamard transform using a simple bit-reversal scheme.     

Complex two-unit system with preventive maintenance

A two-unit warm standby redundant system with repair and preventive maintenance is considered. The pdf of the life time of a unit while in standby is assumed to be Erlangian. The pdfs of all the other random variables are arbitrary. Identifying suitable regeneration points, expressions for the Laplace transforms of the availability and reliability of the system are derived.     

ESD–RF co-design methodology for the state of the art RF-CMOS blocks

This paper describes an approach to design ESD protection for integrated low noise amplifier (LNA) circuits used in narrowband transceiver front-ends. The RF constraints on the implementation of ESD protection devices are relaxed by co-designing the RF and the ESD blocks, considering them as one single circuit to optimise. The method is applied for the design of 0.25 μm CMOS LNA. Circuit protection levels higher than 3 kV HBM stress are achieved using conventional highly capacitive ggNMOS snapback devices. The methodology can be extended to other RF-CMOS circuits requiring ESD protection by merging the ESD devices in the functionality of the corresponding matching blocks.     

Ulcerative systematized porokeratosis (Mibelli)

An unusual clinical variant of porokeratosis (Mibelli's disease) appeared in a patient soon after birth; the lesions were widely distributed mostly on the right half of the body. Spontaneous recurrent ulcerations occurred over certain sites. The right foot was grossly deformed as a result of atrophic scarring after ulcerations. Biopsy specimens of the classical lesion showed cornoid lamella. It is suggested that the term "ulcerative systematized porokeratosis" be used to describe this clinical variant of porokeratosis.     

Preventive health care for children

This article discusses immunization, development, vision, blood pressure, dentition, behavioral, and environmental screening for preschool children. The authors then discuss screening for children in the early school years. Injury and violence prevention and topics of sexuality for the preadolescent are also presented.     

Measurement of capacitances and their loss factors

A method is described for measuring the capacitance values and the loss factors of a pair of capacitors simultaneously. The method uses the principle of oscillators. No standard capacitor is required. The possible errors introduced in the measurements are discussed. Both theoretical and experimental results are provided. The method can be used with any other oscillator circuit that contains only two capacitors     

Growth and properties of Hg1-xCdxTe on GaAs,with x − 0.27

The organometallic vapor phase epitaxy of HgCdTe onto (100)2°-(110) GaAs substrates is described in this paper. A buffer layer of CdTe has been grown prior to the growth of HgCdTe, to take up the large lattice mismatch with the GaAs. Considerations for the thickness of this buffer layer are outlined, and it is shown by quantitative Secondary Ion Mass Spectroscopy that there is negligible diffusion of gallium from the GaAs substrate for the growth conditions described. Hall effect measurements give mobilities comparable to those reported for bulk grown crystals. An extrinsicn-type carrier concentration of 2 × 10¹⁶/cm³ is obtained, and is mainly due to residual impurities in the starting chemicals. The alloy composition has been determined at 298 K by Fourier transform infrared transmission (FTIR) spectrometry; this is found to be extremely uniform over a 15 × 7 mm area, as evidenced by an overlapping of FTIR plots taken over this area. HgCdTe layers have been grown on buffer layers varying in thickness from 0.1 to 1.9μm. It is found that a buffer thickness of about 1.9μm or larger is required to obtain high quality HgCdTe, both in terms of the electrical characteristics (mobility and carrier concentration) and the infrared transmission curves (peak transmission).     

Case Study on Speed Failure Causes in a Microprocessor

In this article, we identify the underlying speed paths and perform a detailed analysis on the effects of multiple input switching, cross-coupling noise, and localized voltage drop on microprocessor. We employ cycle-wise clock shrinks on a tester combined with a CAD methodology to unintrusively identify and analyze these speed paths. Understanding the causes of speed failures can help designers make better power and performance tradeoffs.     

Extrusion of rate-sensitive materials using a viscoplastic constitutive equation and the finite element method

The flow of a rate sensitive material in a forming process in general and an extrusion process in particular has been analysed by using a constitutive equation in the form where such a material is treated as a viscous, non-Newtonian incompressible fluid flow. The discretized form of the flow equation is obtained using the principle of virtual work and the finite element technique. Velocities and pressures are used as primary variables in the formulation.The method which is presently applied to the axisymmetric steady state extrusion of rate sensitive materials can readily be extended to unsteady problems. The two rate-sensitive materials choosen are an aluminium having a definite yield stress and a Pb-Sn eutectic alloy having no detectable yield limit. The results of the present analysis are compared with available experimental values or with that obtained by other methods and in general good agreement is found to exist.