Joint Time-Domain Tracking of Channel and Frequency Offsets for MIMO OFDM Systems

In this paper we address the problem of joint channel and frequency offset estimation and tracking in multiple-input multiple-output (MIMO) OFDM systems for mobile users. The proposed method stems from extended Kalman filtering and is suitable for time-frequency-space selective channels. Separate offset for each MIMO channel branch is considered because of the mobility and rich scattering. The channel taps and the frequency offsets are estimated in time-domain while the equalization is performed in frequency domain. Simulation results demonstrate that the proposed method tracks time-varying channels and frequency offsets with high fidelity. Realistic channel models are used in mobile scenarios. The proposed time-domain approach has improved performance and robustness in comparison to purely frequency domain processing. Computational complexity is lower as well.     

ELECTROSTATIC SEPARATION OF INSULATING AND CONDUCTIVE PARTICLES FROM GRANULAR MIXES

Electrostatic separation is extensively used for the selective sorting of granular mixtures, by means of the electric forces which act on charged or polarized bodies. The roll-type separator with combined corona-electrostatic field has been proved to be the most advantageous solution when the purpose is to isolate conductive particles from non-conductive ones. The paper presents the contributions of the High Intensity Electric Fields Laboratory of the Technical University of Cluj-Napoca to the development of this solution for various industrial applications. The first chapter is devoted to the theoretical analysis of the phenomena and points out the multitude of factors which influence the efficiency of the separation process. A special attention is paid to the study of the corona charging conditions of insulating particles. In the second and third cahpters, the authors show how the results of numerical modeling guided the design of new equipment and the optimization of their operating conditions. Laboratory and pilot plant tests described in the forth chapter brought evidence of the effectiveness of the proposed technologies. The presentation of several applications in the recycling industry concludes the paper.     

Identification of genes differentially expressed in Mycobacterium tuberculosis by differential display PCR

RNA arbitrarily-primed differential display PCR (RAP-PCR) was used to identify and isolate genes differentially expressed between attenuated (H37Ra) and virulent (H37Rv, Erdman) laboratory strains of Mycobacterium tuberculosis (Mtb). Using this method, cDNA fragments showing homology to three known mycobacterial genes and six putative novel genes in mycobacterial cosmid vectors were identified. Among the putative novel Mtb genes identified, we found: (1) gene MTV041.29, containing multiple tandem repetitive sequences and encoding a putative Gly-, Ala, Asn-rich protein (PPE family); (2) gene MTV004.03, containing the AT10S repetitive gene sequence; (3) gene MTV028.09, encoding a hypothetical protein of unknown function; (4) genes MTCY78.20,21, possibly encoding two hypothetical proteins of unknown function; (5) gene MTCY01A6.09, encoding a putative novel ferrodoxin dependent glutamate synthase; and (6) gene MTCY31.20, encoding a putative cyclohexanone monooxygenase. Using gene specific primers in a second differential display PCR and by RT-PCR amplification, novel genes 1, 2, 3 and 4 were shown to be differentially up-regulated in the attenuated Mtb strain H37Ra compared to H37Rv and Erdman strain. Overall, we demonstrated that RAP-PCR, as a first step, is a quick and sensitive method for the identification and isolation of novel genes expressed in Mtb. Because of limitations inherent to the lack of specificity of arbitrary primers in the RAP-PCR method, a second differential display PCR and RT-PCR amplification with gene-specific primers was necessary in order to confirm differential expression of the identified genes.     

Potential field based geometric modelling using the method of fundamental solutions

We propose a new geometric modelling method based on the so‐called potential field (PF) modelling technique. The harmonic problem associated with this technique is solved numerically using the method of fundamental solutions (MFS). We investigate the applicability of the proposed approach to parametrically defined curves of varying complexity. Based on the MFS, we also provide definitions of the Boolean operations associated with the geometric modelling. Finally, we give practical applications of the method to computer‐aided design and manufacturing problems. Copyright © 2006 John Wiley & Sons, Ltd.     

Study washboarding phenomenon in frame sawing machines

The paper concerns washboarding phenomenon where for every kind of sawing a very regular pattern is characterised by a sinusoidal – like variation in board thickness. That pattern is an effect of the saw blade lateral vibrations. It is palpable that these vibrations are detrimental to the cutting process, and lead to poor surface quality and dimensional accuracy, and raw material waste. For band saws in the contemporary literature models explaining a washboarding phenomenon are supported on self-excited (self-induced) vibration theories. However, these explanations cannot be simply broadened into the washboarding phenomenon in frame sawing machines. In this work based on theoretical and experimental investigation the washboard pattern formation is clarified by the authors with the use of a theoretical model, in which the rugged surface is an effect of vibrations generated by lateral cyclic loading and lagged wave formation. The authors hope that their obtained results contribute significantly to further understanding of this important but complicated phenomenon.     

Float-to-fixed and fixed-to-float hardware converters for rapid hardware/software partitioning of floating point software applications to static and dynamic fixed point coprocessors

While hardware/software partitioning has been shown to provide significant performance gains, most hardware/software partitioning approaches are limited to partitioning computational kernels utilizing integers or fixed point implementations. Software developers often initially develop an application using floating point representations built-in to most programming languages and later convert the application to a fixed point representation—a potentially time consuming process. In this paper, we present the Arizona Float ⇔ Fixed Hardware Library (AFFHL) consisting of efficient, configurable floating point to fixed point and fixed point to floating point hardware converters. By utilizing these converters, a system’s hardware/software implementation can be separated into a floating point domain consisting of the microprocessor and memory subsystem and a fixed point domain consisting of one or more partitioned hardware coprocessors. This separation enables a rapid hardware/software partitioning approach in which floating point software kernels can be implemented using fixed point hardware coprocessors without the need for application developers to first rewrite software applications as fixed point implementations. We further present an overview of a basic hardware/software partitioning methodology for rapidly partitioning computational kernels within floating point software application to either statically determined fixed point hardware coprocessors or dynamically adaptable fixed point hardware coprocessors in which the required fixed point representation can be dynamically determined and adjusted at runtime.     

Synthesis and comparative assessment of antiradical activity,toxicity, and biodistribution of κ‐carrageenan‐capped selenium nanoparticles of different size: in vivo and in vitro study

In the present study, water‐soluble hybrid selenium‐containing nanocomposites have been synthesised via soft oxidation of selenide‐anions, preliminarily generated from elemental bulk‐selenium in the base‐reduction system ‘N₂ H₄ –NaOH’. The nanocomposites obtained consist of Se⁰ NPs (4.6–24.5 nm) stabilised by κ‐carrageenan biocompatible polysaccharide. The structure of these composite nanomaterials has been proven using complementary physical–chemical methods: X‐ray diffraction analysis, transmission electron microscopy, optical spectroscopy, and dynamic light scattering. Optical ranges of ‘emission/excitation’ of aqueous solutions of nanocomposites with Se⁰ NPs of different sizes are established and the most important parameters of their luminescence are determined. For the obtained nanocomposites, the expressed antiradical activity against free radicals 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid has been found, the value of which depends on the size of selenium nanoparticles. It is experimentally revealed that all obtained nanocomposites are low toxic (LD₅₀ >2000 mg/kg). It is also found that small selenium nanoparticles (6.8 nm), in contrast to larger nanoparticles (24.5 nm), are accumulated in organisms to significantly increase the level of selenium in the liver, kidneys, and brain (in lesser amounts) of rats.Inspec keywords: nanobiotechnology, free radical reactions, oxidation, enzymes, selenium, solubility, nanofabrication, transmission electron microscopy, X‐ray diffraction, free radicals, reduction (chemical), biomedical materials, nanoparticles, nanomedicine, light scattering, organic‐inorganic hybrid materials, biochemistry, nanocompositesOther keywords: κ‐carrageenan biocompatible polysaccharide, composite nanomaterials, complementary physical–chemical methods, X‐ray diffraction analysis, transmission electron microscopy, optical spectroscopy, dynamic light scattering, optical ranges, expressed antiradical activity, 2,2‐diphenyl‐1‐picrylhydrazyl, 3‐ethylbenzothiazoline‐6‐sulphonic acid, comparative assessment, toxicity, κ‐carrageenan‐capped selenium nanoparticles, water‐soluble hybrid selenium‐containing nanocomposites, soft oxidation, selenide‐anions, elemental bulk‐selenium, base‐reduction system, free radicals, 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid, selenium nanoparticles, nanocomposites, liver, kidneys, brain, luminescence, size 4.6 nm to 24.5 nm     

A Fragment-Based Scoring Function to Re-rank ATP Docking Results

ATP is involved in numerous biochemical reactions in living cells interacting with different proteins. Molecular docking simulations provide considerable insight into the problem of molecular recognition of this substrate. To improve the selection of correct ATP poses among those generated by docking algorithms we propose a post-docking reranking criterion. The method is based on detailed analysis of the intermolecular interactions in 50 high-resolution 3D-structures of ATP-protein complexes. A distinctive new feature of the proposed method is that the ligand molecule is divided into fragments that differ in their physical properties. The placement of each of them into the binding site is judged separately by different criteria, thus avoiding undesirable averaging of the scoring function terms by highlighting those relevant for particular fragments. The scoring performance of the new criteria was tested with the docking solutions for ATPprotein complexes and a significant improvement in the selection of correct docking poses was observed, as compared to the standard scoring function.