A Simplified Scheme of Estimation and Cancellation of Companding Noise for Companded Multicarrier Transmission Systems

Nonlinear companding transform is an efficient method to reduce the high peak-to-average power ratio (PAPR) of multicarrier transmission systems. However, the introduced companding noise greatly degrades the bit-error-rate (BER) performance of the companded multicarrier systems. In this paper, a simplified but effective scheme of estimation and cancellation of companding noise for the companded multicarrier transmission system is proposed. By expressing the companded signals as the summation of original signals added with a companding noise component, and subtracting this estimated companding noise from the received signals, the BER performance of the overall system can be significantly improved. Simulation results well confirm the great advantages of the proposed scheme over other conventional decompanding or no decompanding schemes under various situations

A probabilistic model checking approach to analysing reliability, availability, and maintainability of a single satellite system

Satellites now form a core component for space based systems such as GPS and GLONAS which provide location and timing information for a variety of uses. Such satellites are designed to operate in-orbit and have lifetimes of 10 years or more. Reliability, availability and maintainability (RAM) analysis of these systems has been indispensable in the design phase of satellites in order to achieve minimum failures or to increase mean time between failures (MTBF) and thus to plan maintainability strategies, optimise reliability and maximise availability. In this paper, we present formal modelling of a single satellite and logical specification of its reliability, availability and maintainability properties. The probabilistic model checker PRISM has been used to perform automated quantitative analyses of these properties

The Temporal and Spectral Characteristics of "Fast Rise and Exponential Decay" Gamma-Ray Burst Pulses

In this paper we have analyzed the temporal and spectral behavior of 52 Fast Rise and Exponential Decay (FRED) pulses in 48 long-duration gamma-ray bursts (GRBs) observed by the CGRO/BATSE, using a pulse model with two shape parameters and the Band model with three shape parameters, respectively. It is found that these FRED pulses are distinguished both temporally and spectrally from those in long-lag pulses. Different from these long-lag pulses only one parameter pair indicates an evident correlation among the five parameters, which suggests that at least $\sim$4 parameters are needed to model burst temporal and spectral behavior. In addition, our studies reveal that these FRED pulses have correlated properties: (i) long-duration pulses have harder spectra and are less luminous than short-duration pulses; (ii) the more asymmetric the pulses are the steeper the evolutionary curves of the peak energy ($E_{p}$) in the $\nu f_{\nu}$ spectrum within pulse decay phase are. Our statistical results give some constrains on the current GRB models.Comment: 18 pages, 7 figures, accepted for publication in the Astrophysical Journa

A general comparison theorem for 1-dimensional anticipated BSDEs

Anticipated backward stochastic differential equation (ABSDE) studied the first time in 2007 is a new type of stochastic differential equations. In this paper, we establish a general comparison theorem for 1-dimensional ABSDEs with the generators depending on the anticipated term of $Z$.Comment: 8 page

Molecular characterization and expression analysis of chalcone synthase gene during flower development in tree peony (Paeonia suffruticosa)

Chalcone synthase (CHS, EC: 2.3.1.74) is a key enzyme in the flavonoid and anthocyanin biosynthesis pathway. In order to investigate the role of CHS in tree peony flower coloration mechanism, we isolated and characterized the CHS gene from Paeonia suffruticosa cv. Yu Ji Yan Zhuang and analyzed its spatial and temporal expression patterns during floral development. The cDNA sequence of the CHS gene in P. suffruticosa (Ps-CHS1, genbank accession no. GQ483511) was 1475 bp in full length containing an opening reading frame (ORF) of 1185 bp that encoded a 394 amino acid polypeptide. Bioinformatic analysis showed that, Ps-CHS1 possessed all the conserved active sites for the CHS function as well as the family signature. Sequence alignment and phylogenetic analysis revealed that Ps-CHS1 shared high homology with CHS from plants in Salicaceae, Malvaceae and Rosaceae. The homology-based structural modeling showed that Ps-CHS1 had the typical structure of CHS. Southern blot analysis indicated that CHS was encoded by a small multigene family in the genome of tree peony. Anthocyanidin content in full-opening flower petals accumulated to the highest level. Real-time polymerase chain reaction amplification (PCR) analysis indicated that, Ps-CHS1 showed the highest transcript abundance in petals, moderate levels in sepals, low levels in leaves and stamens, and the lowest levels in carpels. Ps-CHS1 was actively expressed during flower development and increased gradually until reached maximal expression when flower fully opened. These results indicated that Ps- CHS1 was involved in the flower pigmentation of tree peony.Key words: Tree peony (Paeonia suffruticosa), chalcone synthase, expression, anthocyanin