QR decomposition-based matrix inversion for high performance embedded MIMO receivers

Real-time matrix inversion is a key enabling technology in multiple-input multiple-output (MIMO) communications systems, such as 802.11n. To date, however, no matrix inversion implementation has been devised which supports real-time operation for these standards. In this paper, we overcome this barrier by presenting a novel matrix inversion algorithm which is ideally suited to high performance floating-point implementation. We show how the resulting architecture offers fundamentally higher performance than currently published matrix inversion approaches and we use it to create the first reported architecture capable of supporting real-time 802.11n operation. Specifically, we present a matrix inversion approach based on modified squared Givens rotations (MSGR). This is a new QR decomposition algorithm which overcomes critical limitations in other QR algorithms that prohibits their application to MIMO systems. In addition, we present a novel modification that further reduces the complexity of MSGR by almost 20%. This enables real-time implementation with negligible reduction in the accuracy of the inversion operation, or the BER of a MIMO receiver based on this.

Fabrication and Repair of Cartilage Defects with a Novel Acellular Cartilage Matrix Scaffold

The objectives of this study were to develop a three-dimensional acellular cartilage matrix (ACM) and investigate its possibility for use as a scaffold in cartilage tissue engineering. Bovine articular cartilage was decellularized sequentially with trypsin, nuclease solution, hypotonic buffer, and Triton x 100 solution; molded with freeze-drying process; and cross-linked by ultraviolet irradiation. Histological and biochemical analysis showed that the ACM was devoid of cells and still maintained the collagen and glycosaminoglycan components of cartilage. Scanning electronic microscopy and mercury intrusion porosimetry showed that the ACM had a sponge-like structure of high porosity. The ACM scaffold had good biocompatibility with cultured rabbit bone marrow mesenchymal stem cells with no indication of cytotoxicity both in contact and in extraction assays. The cartilage defects repair in rabbit knees with the mesenchymal stem cell-ACM constructs had a significant improvement of histological scores when compared to the control groups at 6 and 12 weeks. In summary, the ACM possessed the characteristics that afford it as a potential scaffold for cartilage tissue engineering.

Extracting S-matrix poles for resonances from numerical scattering data: Type-II Pade reconstruction

We present a FORTRAN 77 code for evaluation of resonance pole positions and residues of a numerical scattering matrix element in the complex energy (CE) as well as in the complex angular momentum (CAM) planes. Analytical continuation of the S-matrix element is performed by constructing a type-II Pade approximant from given physical values (Bessis et al. (1994) [421: Vrinceanu et al. (2000) [24]; Sokolovski and Msezane (2004) [23]). The algorithm involves iterative 'preconditioning' of the numerical data by extracting its rapidly oscillating potential phase component. The code has the capability of adding non-analytical noise to the numerical data in order to select 'true' physical poles, investigate their stability and evaluate the accuracy of the reconstruction. It has an option of employing multiple-precision (MPFUN) package (Bailey (1993) [451) developed by D.H. Bailey wherever double precision calculations fail due to a large number of input partial waves (energies) involved. The code has been successfully tested on several models, as well as the F + H-2 -> HE + H, F + HD : HE + D, Cl + HCI CIH + Cl and H + D-2 -> HD + D reactions. Some detailed examples are given in the text.

Form Follows Media::What is The Matrix as Film, Animation, Game and Comics?

In the digital age, the hyperspace of virtual reality systems stands out as a new spatial notion creating a parallel world to the space we live in. In this alternative realm, the body transforms into a hyperbody, and begins to follow the white rabbit. Not only in real world but also in the Matrix world. The Matrix project of Andy and Larry Wachowski started with a feature film released in 1999. However, The Matrix is not only a film (trilogy). It is a concept, a universe that brings real space and hyperspace together. It is a world represented not only in science fiction films but also in The Animatrix that includes nine animated Matrix films directed by Peter Chung, Andy Jones, Yoshiaki Kawajiri and others, four of which are written by the Wachowskis. The same universe is used in Enter the Matrix, a digital game whose script was written and directed by the brothers and a comic book, The Matrix Comics, which includes twelve different stories by artists like Neil Gaiman and Goef Darrow. The Wachowskis played an active role in the creation and realization of all these “products” of different media. The comic book came last (November 2003), however it is possible to argue that everything came out of comics – the storyboards of the original film. After all the Wachowskis have a background in comics.

In this study, I will focus on the formal analysis of the science fiction world of The Matrix - as a representation of hyperspace - in different media, feature film, animated film, digital game and comic book, focusing on diverse forms of space that come into being as a result of medium differences. To unfold the different formal characters of film, animation, game and comics, concepts and features including framing, flattening, continuity, movement, montage, sound/text, light and color will be discussed. An analysis of these products will help to open up a discussion on the relation of form, media and representation.

Nitride-strengthened reduced activation ferritic/martensitic steels

Two nitride-strengthened reduced activation ferritic/martensitic (RAFM) steels with different Mn contents were investigated. The experimental steels were designed based on the chemical composition of Eurofer 97 steel but the C content was reduced to an extremely low level. Microstructure observation and hardness tests showed that the steel with low Mn content (0.47 wt.%) could not obtain a full martensitic microstructure due to the inevitable δ-ferrite independent of cooling rate after soaking. This steel showed similar room temperature strength and higher strength at 600 °C, but lower impact toughness, compared with Eurofer 97 steel. Fractography of the Charpy impact specimen revealed that the low room temperature toughness should be related to the Ta-rich inclusions initiating the cleavage fracture. The larger amount of V-rich nitrides and more dissolved Cr in the matrix could be responsible for the strength being similar to Eurofer 97 steel. In the second steel developed from the first steel by increasing the Mn content from 0.47 wt.% to 3.73 wt.%, a microstructure of full martensite could be obtained.

Density Matrix Renormalization Group for Dummies

We describe the Density Matrix Renormalization Group algorithms for time dependent and time independent Hamiltonians. This paper is a brief but comprehensive introduction to the subject for anyone willing to enter in the field or write the program source code from scratch. An open source version of the code can be found at: http://www.dmrg.it.

L'Origine. Une lecture du poeme 'Radix, Matrix' de Paul Celan

This article presents a very close analysis of one poem by Paul Celan, demonstrating the important place of Jewish mysticism in his poetry and poetics.

UV VIS AND RESONANCE RAMAN SPECTROELECTROCHEMICAL PROPERTIES OF TRANSITION-METAL CENTERS IMMOBILIZED WITHIN A POLY(AMINO ACID) MATRIX - ILLUSTRATED WITH AN IRON PORPHYRIN

An iron prophyrin complex has been immobilized on the surfaces of platinum, silver, and indium doped-tin oxide coated glass by using the poly(gamma-ethyl L-glutamate)-N-(3-aminopropyl)imidazole derivative 1 as a linking agent, thus allowing-the surface-enhanced resonance Raman and UV-VIS absorption spectra and electrochemical properties of the porphyrin to be studied in solvents in which it is not normally soluble.

Ultra-fast spin dynamics in the 2s2p^2 configuration of C^+ studied by time-dependent R-matrix theory

We employ time-dependent R-matrix theory to study ultra-fast dynamics in the doublet 2s2p(2) configuration of C+ for a total magnetic quantum number M = 1. In contrast to the dynamics observed for M = 0, ultra-fast dynamics for M = 1 is governed by spin dynamics in which the 2s electron acts as a flag rather than a spectator electron. Under the assumption that m(S) = 1/2, m(2s) = 1/2 allows spin dynamics involving the two 2p electrons, whereas m(2s) = -1/2 prevents spin dynamics of the two 2p electrons. For a pump-probe pulse scheme with (h) over bar omega(pump) = 10.9 eV and (h) over bar omega(probe) = 16.3 eV and both pulses six cycles long, little sign of spin dynamics is observed in the total ionization probability. Signs of spin dynamics can be observed, however, in the ejected-electron momentum distributions. We demonstrate that the ejected-electron momentum distributions can be used for unaligned targets to separate the contributions of initial M = 0 and M = 1 levels. This would, in principle, allow unaligned target ions to be used to obtain information on the different dynamics in the 2s2p(2) configuration for the M = 0 and M = 1 levels from a single experime