The VLSI design of a single chip Reed-Solomon encoder

A design for a single chip implementation of a Reed-Solomon encoder is presented. The architecture that leads to this single VLSI chip design makes use of a bit serial finite field multiplication algorithm

Movement, materiality, and the mortuary: Adopting go-along ethnography in research on fetal and neonatal postmortem

This article explores the use of the go-along method in research that takes place “behind closed doors” drawing on qualitative research on postmortem imaging. Often favored in community and urban studies, go-along consists of mobile interviews and observations with respondents in their own environments. We conducted go-alongs with various professionals—from pathologists to hospital chaplains—in a range of settings. We also tracked different forms of materiality in and out of the mortuary space. As the article seeks to show, go-along allowed us to appreciate the complex and mobile nature of postmortem, situating it within the wider landscape of bereavement and memorialization. It also enabled us to illuminate the ways in which the mortuary as a place cannot be fixed “indoors,” but rather, is continually remade through different types of practice. Our analysis emphasizes the value of using go-alongs in indoor settings, and further reinforces a fluid conceptualization of place

Observation of small scale structure using sextupole lensing

Weak gravitational lensing seeks to determine shear by measuring induced quadrupole (elliptical) shapes in background galaxy images. Small impact parameter (a few kpc) gravitational lensing by foreground core masses between 2 10^{9} and 2 10^{12} M_\odot will additionally induce a sextupole shape with the quadrupole and sextupole minima aligned. This correlation in relative orientation of the quadrupole and sextupole provides a sensitive method to identify images which have been slightly curved by lensing events. A general theoretical framework for sextupole lensing is developed which includes several low order coefficients in a general lensing map. Tools to impute map coefficients from the galaxy images are described and applied to the north Hubble deep field. Instrumental PSFs, camera charge diffusion, and image composition methods are modelled in the coefficient determination process. Estimates of Poisson counting noise for each galaxy are used to cut galaxies with signals too small to reliably establish curvature. Curved galaxies are found to be spatially clumped, as would be expected if the curving were due to small impact parameter lensing by localized ensembles of dark matter haloes. Simulations provide an estimate of the total required lensing mass and the acceptable mass range of the constituent haloes. The overdensities and underdensities of visible galaxies and their locations in the Hubble foreground is found to be consistent with our observations and their interpretation as lensing events.Comment: 40 pages, 44 figure

A new result on the Klein-Gordon equation in the background of a rotating black hole

This short paper should serve as basis for further analysis of a previously found new symmetry of the solutions of the wave equation in the gravitational field of a Kerr black hole. Its main new result is the proof of essential self-adjointness of the spatial part of a reduced normalized wave operator of the Kerr metric in a weighted L^2-space. As a consequence, it leads to a purely operator theoretic proof of the well-posedness of the initial value problem of the reduced Klein-Gordon equation in that field in that L^2-space and in this way generalizes a corresponding result of Kay (1985) in the case of the Schwarzschild black hole. It is believed that the employed methods are applicable to other separable wave equations

Multiparticle Schrodinger operators with point interactions in the plane

We study a system of N bosons in the plane interacting with delta function potentials. After a coupling constant renormalization we show that the Hamiltonian defines a self-adjoint operator and obtain a lower bound for the energy. The same results hold if one includes a regular inter-particle potential.Comment: 17 pages, Late

Universality in the merging dynamics of parametric active contours: a study in MRI-based lung segmentation

Measurement of lung ventilation is one of the most reliable techniques of diagnosing pulmonary diseases. The time consuming and bias prone traditional methods using hyperpolarized H${}^{3}$He and ${}^{1}$H magnetic resonance imageries have recently been improved by an automated technique based on multiple active contour evolution. Mapping results from an equivalent thermodynamic model, here we analyse the fundamental dynamics orchestrating the active contour (AC) method. We show that the numerical method is inherently connected to the universal scaling behavior of a classical nucleation-like dynamics. The favorable comparison of the exponent values with the theoretical model render further credentials to our claim.Comment: 4 pages, 4 figure

VLSI architectures for computing multiplications and inverses in GF(2-m)

Finite field arithmetic logic is central in the implementation of Reed-Solomon coders and in some cryptographic algorithms. There is a need for good multiplication and inversion algorithms that are easily realized on VLSI chips. Massey and Omura recently developed a new multiplication algorithm for Galois fields based on a normal basis representation. A pipeline structure is developed to realize the Massey-Omura multiplier in the finite field GF(2m). With the simple squaring property of the normal-basis representation used together with this multiplier, a pipeline architecture is also developed for computing inverse elements in GF(2m). The designs developed for the Massey-Omura multiplier and the computation of inverse elements are regular, simple, expandable and, therefore, naturally suitable for VLSI implementation

A VLSI single chip (255,223) Reed-Solomon encoder with interleaver

A single-chip implementation of a Reed-Solomon encoder with interleaving capability is described. The code used was adapted by the CCSDS (Consulative Committee on Space Data Systems). It forms the outer code of the NASA standard concatenated coding system which includes a convolutional inner code of rate 1/2 and constraint length 7. The architecture, leading to this single VLSI chip design, makes use of a bit-serial finite field multiplication algorithm due to E.R. Berlekamp

Long-term measurements of flow near the Aleutian Islands

In summer 1995, the Alaskan Stream at 173.5W was very intense; the peak geostrophic speed was ≈125 cm s−1, and the computed volume transport above 1000 db, referred to 1000 db, was 9 × 106 m3 s−1). Flow north of the central Aleutians was shallow, convoluted and weak (2– 3 × 106 m3 s−1). A sequence of CTD casts across Amukta Pass, spaced irregularly in time during 1993–1996, showed a mean northward (southward) geostrophic transport of 1.0 (0.4) × 106 m3 s−1, for a net flow into the Bering Sea of 0.6 × 106 m3 s−1. The source of this flow was the Alaskan Stream except in 1995, when it was Bering Sea water. Results from two 13-month current moorings west and east of the pass were quite different. To the west, flow was weak and variable and appeared to have a barotropic component. To the east, flow was stronger and unidirectional eastward