基于FPGA的PUSCH信道估计仿真与实现

基于最小平方(LS)算法,利用FPGA实现了一种适用于TD-LTE系统的上行信道估计算法。主要研究了如何利用FPGA实现LS算法,包括算法的介绍、方案的形成、FPGA实现的处理流程、FPGA实现结果及分析。以Virtex-5芯片为硬件平台,完成了仿真、综合、板级验证等工作。实现结果表明,该信道估计算法应用到TD-LTE系统具有良好的稳定性和可行性。     

基于实际无线局域网系统的信道估计算法

结合无线局域网(WLAN)系统进行适合实际系统的信道估计方法研究。针对实际系统在要求算法稳健性的同时,还要求算法简单易实现的特点,在最小二乘(Least Square,LS)算法中添加了离散傅里叶逆变换(Inverse Discrete Fourier Transform,IDFT)运算,利用信号在时域能量集中的特点,在时域对信号按门限值进行筛选,滤除大部分噪声,以此提高系统性能。仿真结果显示,改进算法可为实际WLAN系统所采用。     

基于系统辨识的无差拍控制在直流电源中的应用

提出了一种基于系统辨识的直流电源的无差拍控制方法。通过对系统参数的离线辨识 ,获得与系统配合得当的无差拍控制参数 ,对电源进行控制。通过计算机模拟仿真和实验 ,证明该方法切实可行     

一个非线性回归模型的 LS 估计量的计算

对一个地铁隧道施工预测中提出的非线性回归模型，研究其ＬＳ估计量的计算方法，并编制了计算程序，较好地解决了这一工程实际问题的计算     

交换机LS中继全自动维护的实现

环路启动(LS)中继在电力专网中使用非常广泛,人工恢复长时间不拆线的LS中继的维护方式已经不能满足需求,故利用开发工具(Delphi)编写软件实现和交换机通信,自动检测所有LS中继线的状态,自动恢复长时间处于维护忙状态的LS中继。文章介绍了该系统的实现过程及系统中各模块的功能。该系统的实现提高了工作效率,保障了交换网的通信质量。     

Numerical simulation of impact behaviour of structures with response adapted to the intensity of shock

This study presents an alternative approach for the absorption of impact energy that uses the internal pressurization of structures in the framework of a crash‐adaptive response. Numerical simulations were conducted on axial impact of thin‐walled tubular structures with circular cross section that serve as an approximation to a front crash box of a motor vehicle. The main objective of this work consists in studying the effect of internal pressurization of tubular structures in a crashworthiness application, as well as the possibility to obtain a reduction in wall thickness thus improving weight efficiency. A numerical study is presented for an internal pressure of 20 bar and tubular structures of circular section and 1.14 mm thickness. Numerical simulations were performed recurring to LS‐DYNA explicit dynamics software while considering for the material a stainless steel alloy that is a material with interest for crashworthiness applications and manufacturing requisites due to its balance between strength, ductility and energy absorption. The results obtained allow concluding that recurring to internal pressurization it is feasible to reduce the wall thickness and have an impact resistance identical to the original while improving overall efficiency.     

一种改进的基于LS的OFDM盲同步算法

在基于LS(lease squares)的OFDM盲同步算法基础上,提出了一种性能优良的OFDM盲同步算法。采样周期取为原算法采样周期的M倍,计算出抽样点处的判决函数值,然后对相邻的判决函数值进行前后移动平均,定时点取为使移动平均值为最小时对应的那2个抽样点的中间位置。仿真结果表明:该算法不仅减少了计算量,而且在复杂的多径衰落信道中,定时和频偏估计性能也有大的改善。     

In Vivo Evaluation of Sgc8-c Aptamer as a Molecular Imaging Probe for Colon Cancer in a Mouse Xenograft Model

Recent biotechnological applications in the field of clinical oncology led to the identification of new biomarkers as molecular targets of cancer, and to broad developments in the field of personalized medicine. Aptamers are oligonucleotides (ssDNA or RNA) that are selected to specifically recognize a molecular target with high affinity and specificity. Based on this, new horizons for their use as molecular imaging probes are being explored. The objective of this work was to evaluate the Sgc8-c aptamer conjugated with Alexa Fluor 647 fluorophore as an imaging probe in a colon tumor xenograft mouse model, with potential application in molecular imaging. In this study, the LS174T cell line was used to induce colorectal adenocarcinoma in nude mice. After confirmation of PTK7 overexpression by immunohistochemistry, in vivo studies were performed. Pharmacokinetic, in vivo and ex vivo biodistribution imaging, and a competition assay were evaluated by fluorescence imaging. In vivo visualization of the probe in the tumors was assessed two hours after aptamer probe administration, exhibiting excellent tumor-to-background ratios in biodistribution studies and high specificity in the competition test. Our results demonstrated the functionality of Scg8-c as an imaging probe for colon cancer, with potential clinical applications.     

基于改进HHT和SVM的滚动轴承故障状态识别

针对滚动轴承故障信号特征难以提取与故障诊断效率较低问题,引入集合经验模态分解(EEMD)对Hilbert-Huang变换(HHT)进行改进,将改进的HHT结合拉普拉斯得分(Laplacian score,LS)进行轴承故障特征提取,并利用遗传算法(GA)优化支持向量机(SVM)分类参数,将其应用于滚动轴承振动信号故障状...     

COMPUTER SIMULATION TECHNIQUES FOR A MOBILE SATELLITE COMMUNICATION CHANNEL

This paper gives a brief and systematic presentation of the computer simulation techniques of satellite communications, especially for a mobile satellite channel, based on a summarization of the author's exploration and experience in this area. It includes the equivalent complex baseband notation (ECBN) method, a very convenient mathematical form for software simulation; development of a multi-functional and expandable channel simulation system on a computer from L-band to Ka-band; channel impulse or frequency response estimation in real time by the technique burst-mode link analyser with least-squares algorithm (BMLA/LS), modelling and simulation of the channel fast fading due to multipath and shadowing; acquisition of the equivalent normalized binary signal-to-noise ratio (E_b/N₀) data at the channel input; and bit-error rate (BER) evaluation by the directly error-counting approach and the computational approach at the channel output in simulation.