4G视频传输模块的硬件设计与信号完整性分析

提出一种基于TMS320DM6467T平台的嵌入式4G视频传输模块的硬件方案,该方案充分利用4G网络的高带宽,可以实现视频信号的快速传输。对方案的硬件设计进行了深入的探讨,分析了各个功能模块。介绍信号完整性分析的重要性,提出4G视频传输模块的信号完整性设计方案。应用HSPICE软件和IBIS模型对硬件电路板进行仿真分析,有效地解决了系统的LPDDR2接口电路中出现的反射、串扰等信号完整性(SI)方面的问题,提高了信号眼图质量,充分保证了电路板设计的质量和信号传输速度,满足视频信号传输的要求。     

智慧政府框架下的政务系统云迁移策略推导

近年来智慧政府建设蓬勃发展,其政务协同、数据共享的发展理念对政务系统整合提出了明确需求。本文以系统云迁移实践为基础,对政务系统特点和属性与系统云迁移策略之间的内在联系进行探究,创造性的提出了一套基于系统属性参量选择适用云迁移策略的推导规则,并将这套规则应用于实际的政务系统云迁移方案制定中。     

音频播控系统改造设计方案浅析

介绍了音频播控系统设计方案的总体结构,分析了智能化主控系统的性能,并详细阐述了系统的设备配置及利用总控系统软件控制各种硬件设备,实现协同工作的特点.通过技术改造,从系统方案到设备配置实现了一个全数字信号路由、智能化的电台系统.     

基于马尔可夫决策的理性秘密共享方案

基于马尔可夫决策理论研究理性密码共享系统模型和秘密重构方法。首先利用马尔可夫决策方法,提出适合于理性秘密共享的系统模型,该模型包括参与者集合、状态集合、风险偏好函数、状态转移函数、回报函数等。在模型中,引入秘密重构中的参与者的风险偏好函数刻画秘密共享模型的状态集合和状态转移函数。其次,基于所提出的系统模型构造相应的理性秘密共享方案,基于马尔可夫策略解决各理性参与者在秘密共享方案中的秘密重构问题。最后对方案进行理论分析证明,给出理性秘密重构方案中折扣因子、回报函数、参与者风险偏好函数间的函数关系,其结果表明所提系统模型方法的合理性和有效性。     

考虑恶意节点的CRN合作频谱感知方法

基于带有恶意节点的更为实际的频谱感知环境,研究了基于合作感知的频谱共享网络模型,次级用户将会根据合作感知结果动态地调整其发射功率。为了防止恶意节点对感知系统的感知性能造成严重影响,研究了如何进行合作感知以提高感知性能。在一定的检测概率和相关功率约束下,建立了一个以最大化次级网络的吞吐量为目标函数的优化问题。仿真实验首先突出说明了恶意节点数目对频谱感知影响重大,同时还表明无论是否存在恶意节点,提出的算法均可有效地计算出最优的感知时间和发射功率,且在降低最大干扰功率限制和最大发射功率限制时,网络的吞吐量是增大的。     

车联网中基于联盟合作博弈的带宽分享策略

近几年来,车联网领域快速发展并引起广泛关注.在此背景下提出了一种混合Wi-Fi、WiMAX和3G/LTE的网络架构,在这种架构下,车辆可以根据自身的情况选择合适的方式接入网络.网络带宽分享采用基于联盟合作博弈的方式,车辆可以选择加入或离开合作联盟来最大化自身收益.模型从理论上证明了通过车辆间的效用分配与博弈合作,最终将形成一个纳什稳定的联盟划分并能适应车辆的动态变化.仿真结果表明,模型的算法性能接近于最优联盟分配.     

Selective collection and detection of MCF-7 breast cancer cells using aptamer-functionalized magnetic beads and quantum dots based nano-bio-probes

A novel strategy for selective collection and detection of breast cancer cells (MCF-7) based on aptamer–cell interaction was developed. Mucin 1 protein (MUC1) aptamer (Apt1) was covalently conjugated to magnetic beads to capture MCF-7 cell through affinity interaction between Apt1 and MUC1 protein that overexpressed on the surface of MCF-7 cells. Meanwhile, a nano-bio-probe was constructed by coupling of nucleolin aptamer AS1411 (Apt2) to CdTe quantum dots (QDs) which were homogeneously coated on the surfaces of monodispersed silica nanoparticles (SiO₂ NPs). The nano-bio-probe displayed similar optical and electrochemical performances to free CdTe QDs, and remained high affinity to nucleolin overexpressed cells through the interaction between AS1411 and nucleolin protein. Photoluminescence (PL) and square-wave voltammetric (SWV) assays were used to quantitatively detect MCF-7 cells. Improved selectivity was obtained by using these two aptamers together as recognition elements simultaneously, compared to using any single aptamer. Based on the signal amplification of QDs coated silica nanoparticles (QDs/SiO₂), the detection sensitivity was enhanced and a detection limit of 201 and 85 cells mL⁻¹ by PL and SWV method were achieved, respectively. The proposed strategy could be extended to detect other cells, and showed potential applications in cell imaging and drug delivery.     

Comparison of the performance of three ion mobility spectrometers for measurement of biogenic amines

The performance of three different types of ion mobility spectrometer (IMS) devices: GDA2 with a radioactive ion source (Airsense, Germany), UV-IMS with a photo-ionization source (G.A.S. Germany) and VG-Test with a corona discharge source (3QBD, Israel) was studied. The gas-phase ion chemistry in the IMS devices affected the species formed and their measured reduced mobility values. The sensitivity and limit of detection for trimethylamine (TMA), putrescine and cadaverine were compared by continuous monitoring of a stream of air with a given concentration of the analyte and by measurement of headspace vapors of TMA in a sealed vial. Preprocessing of the mobility spectra and the effectiveness of multivariate curve resolution techniques (MCR-LASSO) improved the accuracy of the measurements by correcting baseline effects and adjusting for variations in drift time as well as enhancing the signal to noise ratio and deconvolution of the complex data matrix to their pure components. The limit of detection for measurement of the biogenic amines by the three IMS devices was between 0.1 and 1.2 ppm (for TMA with the VG-Test and GDA, respectively) and between 0.2 and 0.7 ppm for putrescine and cadaverine with all three devices. Considering the uncertainty in the LOD determination there is almost no statistically significant difference between the three devices although they differ in their operating temperature, ionization method, drift tube design and dopant chemistry. This finding may have general implications on the achievable performance of classic IMS devices.     

Morphology-controlled electrochemical sensing amaranth at nanomolar levels using alumina

Different-shaped aluminas were readily prepared via hydrothermal reaction. It was found that the morphology and the electrochemical sensing properties of alumina were heavily dependent on the reaction time. When extending the reaction time from 6 h to 24 h, the obtained alumina samples changed from amorphous bumps to regular microfibers in diameter of 200 nm, as confirmed by scanning electron microscopy. Transmission electron microscopy observation revealed that longer reaction time was beneficial for the formation of porous and uniform fiber-like structures. Electrochemical tests proved that alumina microfibers were more active for the oxidation of amaranth and exhibited much higher enhancement effect, compared with alumina bumps. On the surface of alumina microfibers, the oxidation peak currents of amaranth increased remarkably. The influences of pH value, amount of alumina microfibers, and accumulation time on the signal enhancement of amaranth were discussed. As a result, a novel electrochemical method was developed for the detection of amaranth. The linear range was from 1 to 150 nM, and the detection limit was 0.75 nM after 1-min accumulation. The analytical application in drink samples was investigated, and the results consisted with the values that obtained by high-performance liquid chromatography.     

深水多波束测深系统脉冲压缩实时算法

线性调频信号是大时宽带宽积信号,通过脉冲压缩可提高探测距离和分辨率,已在深水多波束测深系统中得到广泛应用。针对深水多波束测深系统中脉冲压缩运算量大的问题,提出了一种基于分组的脉冲压缩实时算法。该算法对需要进行脉冲压缩的波束进行分组,每个节拍只计算一组波束,可大幅减少深水多波束测深系统脉冲压缩的运算时间,节省了处理器资源。该算法已成功应用于某深水多波束测深系统,经多次海试证明,工作稳定可靠。