基于闭包的3NF模式综合算法

文中基于属性集关于函数依赖集的闭包，并采用模式矩阵，给出了一个从函数依赖集综合出３ＮＦ模式的算法。该算法不用Ａｒｍｓｔｒｏｎｇ公理进行烦琐的推导，与Ｂｅｒｎｓｔｅｉｎ算法相比，较为简单且易于实现。     

时滞依赖H∞滤波器的有限频故障检测方法

本文研究了线性离散时滞系统的有限频鲁棒故障检测问题.利用故障估计技术,将故障检测滤波器设计问题转化为时滞依赖的H∞滤波器设计问题.本文直接给出刻画有限频故障检测性能的线性矩阵不等式条件,避免因引入加权函数而产生的不准确性.最后,仿真算例表明时滞依赖的有限频故障检测滤波器可以取得比已有结果更好的故障检测性能.     

基于FD-NOMA的无人机通信系统容量分析

为了提高无人机与地面用户的通信质量，提出了一种基于全双工和非正交多址接入技术的无人机通信系统模型，并分析了城市和郊区两种场景下该系统模型的遍历容量。首先，推导出两种场景下该系统模型的精确容量表达式；然后，通过引入Q函数和利用截断方法解决了式中指数积分函数的计算问题，得到了容量的近似闭式表达式，并在城市场景下，采用取系数因子的方法得到了更精确的容量近似闭式表达式；最后，仿真和数值结果表明，莱斯因子对系统容量存在一定影响，增加无人机数量或非正交多址接入功率向量都可以获得更好的容量性能。     

FD法和故障树法在高压直流输电系统可靠性评估中的比较分析

详细比较了高压直流输电系统可靠性评估中常用的频率和持续时间（FD）法和故障树法,分别给出了各自的优缺点。在子系统划分的基础上分别建立各子系统的状态空间图和故障树图,并加以层层组合,得到整个直流输电系统的状态空间模型和故障树模型。分别采用FD法和故障树法对一单12脉接线高压直流输电系统进行了算例对比分析,计算的可靠性指标包括双极运行、单极停运、双极停运对应的概率、频率、平均持续时间等。     

实时校正时间误差的Farrow结勾滤波器设计

实现1种基于Farrow结构分数时延(Fractional Delay,FD)滤波器对并行采样中时间非均匀误差的实时校正.采用优化设计的方法,求解Farrow结构FD滤波器的各子滤波器系数,在尽可能资源消耗少的情况下,使设计偏差较小,保证后续时延误差估计和校正的精度,并在Xilinx的FPGA中实现时间误差的校正.理论...     

Recommendations for the viability assessment of probiotics as concentrated cultures and in food matrices

Due to the fact that probiotic cells need to be alive when they are consumed, culture-based analysis (plate count) is critical in ascertaining the quality (numbers of viable cells) of probiotic products. Since probiotic cells are typically stressed, due to various factors related to their production, processing and formulation, the standard methodology for total plate counts tends to underestimate the cell numbers of these products. Furthermore, products such as microencapsulated cultures require modifications in the release and sampling procedure in order to correctly estimate viable counts. This review examines the enumeration of probiotic bacteria in the following commercial products: powders, microencapsulated cultures, frozen concentrates, capsules, foods and beverages. The parameters which are specifically examined include: sample preparation (rehydration, thawing), dilutions (homogenization, media) and plating (media, incubation) procedures. Recommendations are provided for each of these analytical steps to improve the accuracy of the analysis. Although the recommendations specifically target the analysis of probiotics, many will apply to the analysis of commercial lactic starter cultures used in food fermentations as well.     

二维Root-MUSIC算法的快速实现方法

目前实际测向系统中所需DSP数目较多,系统设计较复杂,测向时效性不足.针对于此,基于一种改进的二维DOA估计算法-2D FD-Root-MUSIC算法,研究了在FPGA+DSP平台上快速实现DOA估计.首先介绍了数据的量化误差及分析,给出了算法的定点编程实现流程,然后对浮点数据进行量化仿真,确定算法在硬件中的定点位数,...     

应用程函方程的差分解法实现井间地震资料的反射成像

本文给出了一种偏移共炮点道地震资料的方法，它利用程函方程的差分解法求出空间任一点到所有的炮点和接收点处的地震旅行时和射线路径，然后根据斯奈尔定律找出所有的满足反射规律的炮检对，根据其相应道上成像处的地震反射波振幅的叠加来实现地震资料的叠前深度偏移。该方法适应于介质速度的纵向及横向变化。     

一种低复杂度的数字鉴频器

在数字通信系统中，发送端和接收端的载波往往存在一定的频差。当频差较大时，接收端用于载波恢复的锁相环路无法锁定，导致系统不能正常工作。此时可以借助锁频环路来扩大频率捕捉范围，而锁频环路的核心部件则是鉴频器。本文提出了一种低复杂度的数字鉴频器，它能够从解调数据星座点的旋转中提取频差信息，可用于QAM和PSK调制方式的频率捕捉。结果表明，这种鉴频器不但具有较大的频率捕捉范围，而且非常易于实现。     

Breakeven price of biomass from switchgrass,big bluestem,and Indiangrass in a dual-purpose production system in Tennessee

The objective was to determine the breakeven price for switchgrass (SG) (Panicum virgatum L.), a mix of big bluestem (Andropogon gerardii Vitman) and Indiangrass (BBIG) (Sorghastrum nutans L. Nash), and a combination of SG and BBIG (SG/BBIG) produced under three harvest treatments. Two-harvest treatments included a forage harvest at early boot (EB) and at early seedhead (ESH) plus a biomass harvest at fall dormancy (FD). The third harvest treatment was a single biomass harvest at FD. Mixed models were used to determine if there were differences in yield, crude protein, and nutrient removal for each of the native warm-season grass (NWSG) treatments at each harvest. The EB plus FD harvest system would be preferred over the ESH plus FD harvest system for all NWSG treatments. BBIG was the only NWSG treatment with a breakeven price for biomass that decreased with an EB harvest. For all three NWSG treatments, a producer would be better off harvesting once a year for biomass than twice for forage and biomass. The cost of harvesting and replacing the nutrients for the forage harvest was greater than the revenue received from selling the forage.