3,668 research outputs found

    A hybrid M-algorithm/sequential decoder for convolutional and trellis codes

    Get PDF
    The Viterbi Algorithm (VA) is optimum in the sense of being maximum likelihood for decoding codes with a trellis structure. However, since the VA is in fact an exhaustive search of the code trellis, the complexity of the VA grows exponentially with the constraint length upsilon. This limits its application to codes with small values of upsilon and relatively modest coding gains. The M-Algorithm (MA) is a limited search scheme which carries forward M paths in the trellis, all of the same length. All successors of the M paths are extended at the next trellis depth, and all but the best M of these are dropped. Since a limited search convolutional decoder will flounder indefinitely if one of the paths in storage is not the correct one, the data are usually transmitted in blocks. It has been shown that the performance of the MA approaches the VA at high signal to noise ratios (SNR's) with an M which is far less than the 2 sup upsilon states in the full trellis. Thus the MA can be used with larger values of upsilon, making larger coding gains possible at high SNR's. However, it still requires a relatively large fixed computational effort to achieve good performance

    Bandwidth efficient CCSDS coding standard proposals

    Get PDF
    The basic concatenated coding system for the space telemetry channel consists of a Reed-Solomon (RS) outer code, a symbol interleaver/deinterleaver, and a bandwidth efficient trellis inner code. A block diagram of this configuration is shown. The system may operate with or without the outer code and interleaver. In this recommendation, the outer code remains the (255,223) RS code over GF(2 exp 8) with an error correcting capability of t = 16 eight bit symbols. This code's excellent performance and the existence of fast, cost effective, decoders justify its continued use. The purpose of the interleaver/deinterleaver is to distribute burst errors out of the inner decoder over multiple codewords of the outer code. This utilizes the error correcting capability of the outer code more efficiently and reduces the probability of an RS decoder failure. Since the space telemetry channel is not considered bursty, the required interleaving depth is primarily a function of the inner decoding method. A diagram of an interleaver with depth 4 that is compatible with the (255,223) RS code is shown. Specific interleaver requirements are discussed after the inner code recommendations

    FINANCIAL STRUCTURE FOUNDATION OF THE URBAN– RURAL INCOME GAP IN CHINA: AN INVESTIGATION FROM THE PERSPECTIVE OF THE DOUBLE DUAL STRUCTURE

    Get PDF
    This article is an empirical analysis of the relations between financial structure and the urban–rural income gap (URIG) in China’s economic transition, based on the country’s double dual structure. We employ data of 31 provinces in China from 2001 to 2016 to empirically study the influence of financial structure on the URIG. We find an inverted U-shaped relation between financial scale and the URIG, a positive impact of urban and rural financial structure on the URIG, and an inverted U-shaped relation between the mismatch of financial resources and the URIG. These findings show that selection of the optimal proportion of the state-owned economy through ownership reform and the promotion of financial development and optimization of the allocation of financial resources are two effective ways to reduce the URIG.This article is an empirical analysis of the relations between financial structure and the urban–rural income gap (URIG) in China’s economic transition, based on the country’s double dual structure. We employ data of 31 provinces in China from 2001 to 2016 to empirically study the influence of financial structure on the URIG. We find an inverted U-shaped relation between financial scale and the URIG, a positive impact of urban and rural financial structure on the URIG, and an inverted U-shaped relation between the mismatch of financial resources and the URIG. These findings show that selection of the optimal proportion of the state-owned economy through ownership reform and the promotion of financial development and optimization of the allocation of financial resources are two effective ways to reduce the URIG

    Closed-loop three-level charged quantum battery

    Full text link
    Quantum batteries are energy storage or extract devices in a quantum system. Here, we present a closed-loop quantum battery by utilizing a closed-loop three-state quantum system in which the population dynamics depends on the three control fields and associated phases. We investigate the charging process of the closed-loop three-level quantum battery. The charging performance is greatly improved due to existence of the third field in the system to form a closed-contour interaction. Through selecting an appropriate the third control field, the maximum average power can be increased, even far beyond the most ideal maximum power value of non-closed-loop three-level quantum battery (corresponding to the most powerful charging obtainable with minimum quantum speed limit time and the maximum charging energy). We study the effect of global driving-field phase on the charging process and find the maximum extractable work (`ergotropy') and charging power vary periodically under different control field, with a period of 2π2\pi. Possible experimental implementation in nitrogen-vacancy spin is discussed

    (Methanolato)(pyridine)[N 2,N 2′-(pyridine-2,6-diyldicarbon­yl)diacetohydra­zide(2–)]iron(III) methanol solvate

    Get PDF
    In the title complex, [Fe(C11H10N5O4)(CH3O)(C5H5N)]·CH4O, the FeIII ion has a distorted penta­gonal-bipyramidal geometry. In the crystal structure, mol­ecules are linked into one-dimensional chains along [1 ] via inter­molecular O—H⋯O and N—H⋯O hydrogen bonds

    Genetic diversity analysis of cocksfoot (Dactylis glomerata L.) accessions with sequence-related amplified polymorphism (SRAP) and inter-simple sequence repeat (ISSR) markers

    Get PDF
    Sequence-related amplified polymorphism (SRAP) and inter-simple sequence repeat (ISSR), two advanced molecular markers for genetic research in grass and forage, were used to analyze the genetic diversity among 44 accessions of cocksfoot collected from seven countries and regions. 21 SRAP primer combinations generated 476 bands, of which 401 were polymorphic (84.24%). Using 12 ISSR primers, 100 polymorphic bands out of 115 bands in total were generated (86.96%). The coefficient of genetic similarity from SRAP and ISSR data ranged from 0.6838 to 0.9686 and from 0.6935 to 0.9231, respectively. Based on unweighted pair group method with arithmetic mean (UPGMA) cluster and principal component analysis (PCA) on a series of genetic characteristics, all accessions were divided into three clusters and four clusters using two markers, respectively. Those, accessions collected from the identical continent were classified into the same cluster, suggesting the geographical distribution of genetic diversity of cocksfoot. The genetic diversity of Chinese cocksfoot except for three Chinese cultivars was rather rich and greater than that of other regions. We proposed that both SRAP and ISSR markers were considered as useful tools for evaluating the genetic diversity of cocksfoot. Especially, SRAP detected more variance and gave clearer cluster groups.Keywords: Cocksfoot, genetic diversity, sequence-related amplified polymorphism (SRAP), inter-simple sequence repeat (ISSR), germplas

    The signal transduction pathway of PKC/NF-κB/c-fos may be involved in the influence of high glucose on the cardiomyocytes of neonatal rats

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>High glucose could induce structure and function change in cardiomyocytes, PKC plays a core effect in the onset and progression of diabetic cardiomyopathy, but its underlying downstream signal transduction pathway is still not completely understood.</p> <p>Objectives</p> <p>To study the influence of high glucose on the structure, function and signal transduction pathway of PKC (Protein Kinase C)/NF-κB(Nuclear factor-κB)/c-fos in cultured cardiomyocytes.</p> <p>Methods</p> <p>Using cultured cardiomyocytes of neonatal Sprague-Dawley rats as a model, groups were divided into: control group (glucose: 5 mmol/L); high glucose group (glucose: 10 mmol/L, 15 mmol/L, 20 mmol/L, 25.5 mmol/L); equimolar mannital group (5 mmol/L glucose + 20.5 mmol/L maninital); high glucose(25.5 mmol/L) add PKC inhibitor (Ro-31-8220, 50 nmol/L); high glucose (25.5 mmol/L) add NF-κB inhibitor (BAY11-7082, 5 μmol/L). The cellular contracting frequency and volumes were measured and the expression of PKC-α, PKC-β2, p-PKC-α, p-PKC-β2, NF-κB, p-NF-κB, TNF-α (tumor necrosis factor-α) and c-fos were measured by western blot or RT-PCR.</p> <p>Results</p> <p>Cardiomyocytes cultured in high glucose level, but not iso-osmotic mannital, showed an increased pulsatile frequency and higher cellular volumes consistent with the increased glucose levels, and also higher expression of PKC-α, PKC-β2, p-PKC-α, p-PKC-β2, NF-κB, p-NF-κB, TNF-α and c-fos. The addition of Ro-31-8220 and BAY11-7082 could partly reverse these changes induced by high glucose level.</p> <p>Conclusion</p> <p>High glucose significantly increased the pulsatile frequency and cellular volumes of cultured cardiomyocytes via PKC/NF-κB/c-fos pathway, which might lead to diabetic cardiomyopathy.</p

    {4′-[4-(4,4′-Bipyridin-1-ylmeth­yl)phen­yl]-2,2′:6′,2′′-terpyridine}chloridoplatinum(II) bis­(perchlorate) acetonitrile disolvate sesquihydrate

    Get PDF
    The asymmetric unit of the title compound, [PtCl(C32H24N5)](ClO4)2·2CH3CN·1.5H2O, comprises two unique PtII complex cations, four perchlorate anions, four acetonitrile solvent mol­ecules and three water mol­ecules. The Pt atom is four-coordinated by a tridentate chelating 2,2′:6′,2′′-terpyridine ligand and a chloride ion in a square-planar geometry with modest distortion imposed by the constraint of the terpyridyl ligand. The r.m.s. deviations from the plane comprising the four ligand donor atoms and the Pt atom are 0.0381 and 0.0472 Å in the two complex cations
    corecore