Hybrid beamforming for single carrier mmWave MIMO systems

Hybrid analog and digital beamforming (HBF) has been recognized as an attractive technique offering a tradeoff between hardware implementation limitation and system performance for future broadband millimeter wave (mmWave) communications. In contrast to most current works focusing on the HBF design for orthogonal frequency division multiplexing based mmWave systems, this paper investigates the HBF design for single carrier (SC) systems due to the advantage of low peak-to-average power ratio in transmissions. By applying the alternating minimization method, we propose an efficient HBF scheme based on the minimum mean square error criterion. Simulation results show that the proposed scheme outperforms the conventional HBF scheme for SC systems.Comment: IEEE GlobalSIP2018, Feb. 201

GENE REGULATORY NETWORKS OF AGL15 A PLANT MADS TRANSCRIPTION FACTOR

Plant embryogenesis is an intriguing developmental process that is controlled by many genes. AGAMOUS Like 15 (AGL15) is a MADS-domain transcriptional regulator that accumulates preferentially during this stage. However, at the onset of this work it was unknown which genes are regulated by AGL15 or how AGL15 is regulated. This dissertation is part of the ongoing effort to understand the biological roles of AGL15. To decipher how AGL15 functions during plant development, a chromatin immunoprecipitation (ChIP) approach was adapted to obtain DNA fragments that are directly bound by AGL15 in vivo. Putative AGL15 targets were isolated, and binding and regulation was confirmed for one such target gene, ABF3. In addition, microarray experiments were performed to globally assess genes that are differentially expressed between wild type and agl15 young seeds. Among them, a gene, At5g23405, encoding an HMGB domain protein was identified and its response to AGL15 was confirmed. Preliminary results suggest that the loss-of-function of At5g23405 might have an effect on somatic embryogenesis, consistent with AGL15 repression of the expression of this gene. Lastly, to address the question about how the regulator is regulated, the cis elements controlling the expression of AGL15 must be identified. Deletion analysis of the AGL15 promoter indicated the presence of putative positive and negative cis elements contributing to the expression of AGL15. Further analysis suggested that AGL15 regulates the expression of its own gene and this regulation may partially be explained by the direct binding of the protein to the AGL15 promoter. The data presented in this dissertation demonstrate that ChIP can be used to identify previously unsuspected targets of AGL15. Based on ChIP, a ChIP-chip technique is being developed in the lab to allow a more global analysis of in vivo binding sites. The identification of target genes and cis elements in AGL15 promoter is a step towards characterization of the biological roles of AGL15

BcB_c Exclusive Decays to Charmonium and a Light Meson at Next-to-Leading Order Accuracy

In this paper the next-to-leading order (NLO) corrections to $B_c$ meson exclusive decays to S-wave charmonia and light pseudoscalar or vector mesons, i.e. $\pi$, $K$, $\rho$, and $K^*$, are performed within non-relativistic (NR) QCD approach. The non-factorizable contribution is included, which is absent in traditional naive factorization (NF). And the theoretical uncertainties for their branching ratios are reduced compared with that of direct tree level calculation. Numerical results show that NLO QCD corrections markedly enhance the branching ratio with a K factor of 1.75 for $B_{c}^{\pm}\to \eta_{c} \pi^{\pm}$ and 1.31 for $B_{c}^{\pm}\to J/\psi \pi^{\pm}$. In order to investigate the asymptotic behavior, the analytic form is obtained in the heavy quark limit, i.e. $m_b \to \infty$. We note that annihilation topologies contribute trivia in this limit, and the corrections at leading order in $z= m_c/m_b$ expansion come from form factors and hard spectator interactions. At last, some related phenomenologies are also discussed.Comment: 20 pages, 7 figures and 5 table