Blind Channel Identification for Cyclic-Prefixed MIMO-OFDM Systems with Virtual Carriers

This paper applies the repetition index scheme(RIS)to the channel identification of cyclic prefixed(CP)multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM)systems with virtual carriers(VCs)in the environment of the number of receive antennas being no less than that of transmit antennas.The VCs will cause a rank deficiency problem in computing the subspace information.With the subcarrier mapping matrix,the received signal is simplified to remove the rank deficiency.We use the RIS scheme to generate many times of equivalent symbols so the channel identification can converge with few received OFDM blocks.The RIS scheme will convert the white noise into non-white noise.With the Cholesky factorization,a noise whitening technique is developed to turn the non-white noise back to white noise.We further analyze the necessary conditions of identifiability of channel estimation.Simulations are performed to show the superiority of the proposed method.

Anti-tumor effect of statin on pancreatic adenocarcinoma:From concept to precision medicine

A statin is a cholesterol-lowering agent,which inhibits HMG-CoA(3-hydroxy-3-methylglutaryl-coenzyme A)reductase and subsequently reduces the cholesterol precursor,and was first used commercially in 1987.The concept of cholesterol restriction leading to cancer cell dysfunction was proposed in 1992.The interruption of different signaling pathways has been proved in preclinical experiments to elucidate the anti-tumor mechanism of statins in pancreatic adenocarcinoma.Observational studies have shown that the clinical use of statins is beneficial in patients with pancreatic adenocarcinoma,including a chemoprevention effect,post-surgical resection follow-up and therapeutic prognosis of advanced cancer stage.Arrest of the cancer cell cycle by the combined use of gemcitabine and statin was observed in a cell line study.The effect of microbiota on the tumor microenvironment of pancreatic adenocarcinoma is a new therapeutic approach as statins can modulate the gut microbiota.Hence,further randomized trials of statins in pancreatic adenocarcinoma treatment will be warranted with application of precision medicine from microbiota-derived,cell cycle-based and signaling pathway-targeted research.

Surface Modification of Multiferroic BiFeO₃Ceramic by Argon Sputtering

Films fabricated by sputter deposit are extensively used in the semiconductor, optical and optoelectronic industries. However, studies to-date have focused only on analyzing the BFO films fabricated by sputter deposition. This paper’s research seeks to fill the gap in understanding the sputter effect on the target in order to fully understand the whole process of fabricating films by sputter deposition. In this study, 3 keV argon ions were continuously sputtered onto a target of multiferroic bismuth ferrite, BiFeO3, (BFO) with 5 mol% BaTiO3, in increasing time intervals. X-ray Photoelectron Spectroscopy (XPS) was applied to examine the sputtered surface after each sputter time interval. This paper makes the following findings. First, the surface-contaminant carbon was almost completely removed after 5120 seconds of sputtering. Second, the study observed two-component oxygen spectra remained after sputtering. Other than the chemi- and physic-sorbed oxygen, these two oxygen components perhaps resulted from the short and long O-Fe bonds due to the displacement of the Fe3+ ions. Third, sputtering resulted in a change of the oxidation states of bismuth from dominant Bi3+ state to equally weighted Bi3+ state and metallic Bi&#176 state. The changes of the bismuth’s oxidation states, i.e., a non-stoichiometric BFO target might alter the film compositions deposited onto the substrate. This paper shows by introducing low pressure oxygen during the sputtering, the metallic Bio on the target can be re-oxidized.

Hardware Design of Moving Object Detection on Reconfigurable System

Moving object detection including background subtraction and morphological processing is a critical research topic for video surveillance because of its high computational loading and power consumption. This paper proposes a hardware design to accelerate the computation of background subtraction with low power consumption. A real-time background subtraction method is designed with a frame-buffer scheme and function partition to improve throughput, and implemented using Verilog HDL on FPGA. The design parallelizes the computations of background update and subtraction with a seven-stage pipeline. A stripe-based morphological processing and accounting for the completion of detected objects is devised. Simulation results for videos of VGA resolutions on a low-end FPGA device show 368 fps throughput for only the real-time background subtraction module, and 51 fps for the whole system, including off-chip memory access. Real-time efficiency with low power consumption and low resource utilization is thus demonstrated.

On the CR Poincaré–Lelong Equation, Yamabe Steady Solitons and Structures of Complete Noncompact Sasakian Manifolds

In this paper, we solve the so-called CR Poincare-Lelong equation by solving the CR Poisson equation on a complete noncompact CR （2n ＋ 1）-manifold with nonegative pseudohermitian bisectional curvature tensors and vanishing torsion which is an odd dimensional counterpart of Kahler geometry. With applications of this solution plus the CR Liouvelle property, we study the structures of complete noncompact Sasakian manifolds and CR Yamabe steady solitons.