Iterative Detection of Diagonal Block Space Time Trellis Codes, TCM and Reversible Variable Length Codes for Transmission over Rayleigh Fading Channels

Iterative detection of Diagonal Block Space Time Trellis Codes (DBSTTCs), Trellis Coded Modulation (TCM) and Reversible Variable Length Codes (RVLCs) is proposed. With the aid of efficient iterative decoding, the proposed scheme is capable of providing full transmit diversity and a near channel capacity performance. The performance of the proposed scheme was evaluated when communicating over uncorrelated Rayleigh fading channels. Explicitly, significant iteration gains were achieved by the proposed scheme, which was capable of performing within 2~dB from the channel capacity

Performance of bolted steel-beam to CFST-column joints using stiffened angles in column-removal scenario

This paper presents three experimental investigations on the performance of steel-beam to CFST-column joints using stiffened angle, long bolts and fin plate under a middle column removal scenario. Three specimens were designed and tested. The failure modes and catenary action are investigated in detail. The test results show that increasing the angle plate thickness at the joint could not only improve its performance significantly, but also trigger an early formation of catenary action. Increasing the length of short-limb had influence on the deformation ability of the proposed joint, rather than the load capacity. The buckling of stiffeners could prevent the brittle failure of the joints. With the contribution of catenary action, the joint shows much higher rotation capacities than that required in DoD design guidance. The initial stiffness of the joint was calculated using an analytical model with consideration of bolt pretension. Good agreement to the test results is achieved. A numerical analysis is also carried out, whose results show that adding additional row of bolts would improve the redundancy of the joint under column loss. An equivalent dynamic response evaluation of the joints was also performed. The results show that dynamic amplification coefficient should be worked out considering catenary action under large deformation

Plasmon assisted transmission of high dimensional orbital angular momentum entangled state

We present an experimental evidence that high dimensional orbital angular momentum entanglement of a pair of photons can be survived after a photon-plasmon-photon conversion. The information of spatial modes can be coherently transmitted by surface plasmons. This experiment primarily studies the high dimensional entangled systems based on surface plasmon with subwavelength structures. It maybe useful in the investigation of spatial mode properties of surface plasmon assisted transmission through subwavelength hole arrays.Comment: 7 pages,6 figure

A Purely Symbol-Based Precoded and LDPC-Coded Iterative-Detection Assisted Sphere-Packing Modulated Space-Time Coding Scheme

In this contribution, we propose a purely symbol-based LDPC-coded scheme based on a Space-Time Block Coding (STBC) signal construction method that combines orthogonal design with sphere packing, referred to here as (STBCSP). We demonstrate that useful performance improvements may be attained when sphere packing aided modulation is concatenated with non-binary LDPC especially, when performing purely symbol-based turbo detection by exchanging extrinsic information between the non-binary LDPC decoder and a rate-1 non-binary inner precoder. We also investigate the convergence behaviour of this symbol-based concatenated scheme with the aid of novel non-binary Extrinsic Information Transfer (EXIT) Charts. The proposed symbol-based turbo-detected STBC-SP scheme exhibits a 'turbo-cliff' at Eb/N0 = 5.0 dB and achieves an Eb/N0 gain of 19.2dB at a BER of 10-5 over Alamouti’s scheme

Microturbulence studies in RFX-mod

Present-days Reversed Field Pinches (RFPs) are characterized by quasi-laminar magnetic configurations in their core, whose boundaries feature sharp internal transport barriers, in analogy with tokamaks and stellarators. The abatement of magnetic chaos leads to the reduction of associated particle and heat transport along wandering field lines. At the same time, the growth of steep temperature gradients may trigger drift microinstabilities. In this work we summarize the work recently done in the RFP RFX-mod in order to assess the existence and the impact upon transport of such electrostatic and electromagnetic microinstabilities as Ion Temperature Gradient (ITG), Trapped Electron Modes (TEM) and microtearing modes.Comment: Work presented at the 2010 Varenna workshop "Theory of Fusion Plasmas". To appear in Journal of Physics Conference Serie

A Turbo-Detection Aided Serially Concatenated MPEG-4/TCM Videophone Transceiver

A Turbo-detection aided serially concatenated inner Trellis Coded Modulation (TCM) scheme is combined with four different outer codes, namely with a Reversible Variable Length Code (RVLC), a Non-Systematic Convolutional (NSC) code a Recursive Systematic Convolutional (RSC) code or a Low Density Parity Check (LDPC) code. These four outer constituent codes are comparatively studied in the context of an MPEG4 videophone transceiver. These serially concatenated schemes are also compared to a stand-alone LDPC coded MPEG4 videophone system at the same effective overall coding rate. The performance of the proposed schemes is evaluated when communicating over uncorrelated Rayleigh fading channels. It was found that the serially concatenated TCM-NSC scheme was the most attractive one in terms of coding gain and decoding complexity among all the schemes considered in the context of the MPEG4 videophone transceiver. By contrast, the serially concatenated TCM-RSC scheme was found to attain the highest iteration gain among the schemes considered

Olig2/Plp-positive progenitor cells give rise to Bergmann glia in the cerebellum.

NG2 (nerve/glial antigen2)-expressing cells represent the largest population of postnatal progenitors in the central nervous system and have been classified as oligodendroglial progenitor cells, but the fate and function of these cells remain incompletely characterized. Previous studies have focused on characterizing these progenitors in the postnatal and adult subventricular zone and on analyzing the cellular and physiological properties of these cells in white and gray matter regions in the forebrain. In the present study, we examine the types of neural progeny generated by NG2 progenitors in the cerebellum by employing genetic fate mapping techniques using inducible Cre-Lox systems in vivo with two different mouse lines, the Plp-Cre-ER(T2)/Rosa26-EYFP and Olig2-Cre-ER(T2)/Rosa26-EYFP double-transgenic mice. Our data indicate that Olig2/Plp-positive NG2 cells display multipotential properties, primarily give rise to oligodendroglia but, surprisingly, also generate Bergmann glia, which are specialized glial cells in the cerebellum. The NG2+ cells also give rise to astrocytes, but not neurons. In addition, we show that glutamate signaling is involved in distinct NG2+ cell-fate/differentiation pathways and plays a role in the normal development of Bergmann glia. We also show an increase of cerebellar oligodendroglial lineage cells in response to hypoxic-ischemic injury, but the ability of NG2+ cells to give rise to Bergmann glia and astrocytes remains unchanged. Overall, our study reveals a novel Bergmann glia fate of Olig2/Plp-positive NG2 progenitors, demonstrates the differentiation of these progenitors into various functional glial cell types, and provides significant insights into the fate and function of Olig2/Plp-positive progenitor cells in health and disease