采用粒子群优化算法的无人机实时航迹规划

战场环境是动态变化的,很难预先获得全局精确的威胁信息,因此需要无人机具备一定的实时航迹规划能力.采用连续型粒子群优化(PSO)算法进行无人机参考航迹的实时规划,以最大转弯半径、步进、最短距离和回避威胁作为适应度函数的评价指标,得到代表最优航路的离散点.对算法进行了相应的仿真,结果表明该方法费时短,占用内存少,可以满足在线实时航迹规划的要求.     

浅析教学中的关联速度问题

高中物理学习过程中,在学习运动的合成与分解时,教师和学生都会遇到一些经典的关联速度问题.学生解决此类问题时也常常出错,教师的讲解往往看似合理,实质还是有背逻辑思维.文章分析了关联速度中的经典例题:绳拉船的问题,并且指出了许多教师的解法存在的争议,还讨论了更合理的常规解法和适于中学生理解的方法.文章中的"关联速度问题的中...     

UMTS音频编码标准研究

未来的编码技术需要将信号处理方面的进展与局部频谱信息技术结合起来。降低计算复杂性是编解码算法演进的主要推动力。文章给出了音频编解码的目标,详细分析了音频编码的原理,研究了MPEG-1、MPEG-2 BC、MPEG-2 AAC、MPEG-4低时延AAC、MPEG-4高效AAC和增强的MPEG-4高效AAC的应用场合、抽样频率和比特率。     

基于Handel-C的微处理器设计

Handel-C是一种起源于ISO/ANSI-C的硬件设计编程语言,它是以硬件为目标,兼有常规高级语言和硬件描述语言的优点,即它能描述一些复杂算法,又能实现并行执行,真正做到了用软件的方法来设计硬件.本文在分析和研究基于Handel-C语言的FPGA设计的基础上,针对一个具体的简单微处理器进行设计,并在FPGA上实现了该微处理器的功能.     

对以太网无源光网络中OAM的分析

以太网无源光网络(EPON)作为一种新兴的接入技术,需要网络设计者提供电信级(Carrier-class)的管理能力,而单纯的简单网络管理协议(SNMP)已经不能胜任其运营、管理、维护(OAM)的要求.文章提出了基于802.3ahOAM协议和SNMP的EPON系统管理机制,并描述TEPON系统OAM的功能、特点以及在Linux操作系统下该刚络管理机制的软件实现方案.     

基于DSP技术的RFID读写器设计

文中介绍了RFID系统及RFID读写器,论述了基于DSP技术的RFID读写器设计方法.在描述RFID系统组成的基础上,给出了读写器的软硬件设计流程.重点阐述了RFID读写器的防冲突设计.该读写器已应用于门禁系统中,实际应用结果表明其性能良好.     

广播电视覆盖预测地理空间分析方法研究

频率资源的有限性决定了频率资源高效利用和有效管理的重要性,在广播电视由模拟向数字转换的过渡时期,这一需求会更加迫切.本文在分析覆盖预测及其对地理空间信息需求的基础上,着重研究了覆盖预测过程中的地形剖面提取及关键阻挡点分析、阻挡因子计算、地表覆盖物影响分析等地理空间信息分析及处理方法,并在现有的GIS频率覆盖规划平台上实现了基于地形分析的场强区域覆盖预测.     

A 20.8-Gbps Dual-Carrier Wireless Communication Link in 220-GHz Band

With the successful demonstration of terahertz (THz) high-speed wireless data transmission,the THz frequencies are now becoming a worth candidate for post-5G wi...     

Measurements and Characterization for the Vehicle-to-Infrastructure Channel in Urban and Highway Scenarios at 5.92GHz

In the future smart transportation system, reliable vehicle-to-infrastructure(V2 I) communication is very important to ensure vehicle driving safety and to improve vehicle driving efficiency. In this paper, V2 I channel measurements at 5.92 GHz are conducted in typical urban and highway scenarios.The frequency and bandwidth of transmission, as well as the deployment of the RSU(roadside unit) and the OBU(on board unit), are selected by considering the recommendation proposed by 3 GPP TR 36.885. T...     

Flavonoids from Lycium barbarum Leaves Exhibit Anti-Aging Effects through the Redox-Modulation

Lycium barbarum leaves are a kind of vegetable, and modern nutrition studies have found that they have an anti-aging function. Our study aims to investigate the anti-aging effects of Lycium barbarum leaf flavonoid (LBLF) extracts and its underlying molecular mechanism. LBLFs were purified using D101 and polyamide resin, characterized by ultraperformance liquid chromatography coupled with mass spectrometry, and administered to hydrogen peroxide (H₂O₂)-treated human umbilical vein endothelial cells (HUVECs) and Caenorhabditis elegans. Appropriate enrichment conditions were optimized through dynamic adsorption and desorption experiments, the content of flavonoids reached 909.84 mg/g, rutin and kaempferol being the main ones. LBLFs attenuated H₂O₂-induced HUVEC apoptosis, decreased reactive oxygen species and malondialdehyde production levels, increased superoxide dismutase, glutathione peroxidase and catalase activities. Furthermore, pre-treatment with LBLF increased mRNA expression of erythropoietin (EPO) and heme oxygenase-1 (HO-1) via the mitogen-activated protein kinase (MAPK) signaling pathway in HUVECs. Compared with 100 µM rutin monomer, LBLF prolonged the lifespan of Caenorhabditis elegans, enhanced their mobility in middle life stages and upregulated expression of sod-2, gcs-1 and skn-1 genes, which indicated that the anti-aging effects of LBLF were due to its redox-modulation.