基于扩张状态观测器的路面附着系数实时估计

对车辆动力学控制中的道路路面附着系数实时估计问题进行研究.首先使用魔术公式建立1/4车辆制动模型,即车轮制动动力学模型;然后将其中的附着系数相关项视为制动系统的扩张状态,建立其扩张状态观测器,通过轮速信号和制动力矩信号实时观测制动过程中地面与轮胎间的纵向力,进而计算出路面附着系数;最后在均匀路面和突变路面条件下进行仿真研究.结果表明,所提出的方法对车辆制动系统参数摄动和传感器噪声具有鲁棒性,可以准确地实现道路路面附着系数的实时估计,观测器与控制器设计具有一定独立性.     

水土保持生物措施的研究

对多年来的水土保持生物措施研究进行了分析总结,内容包括水土保持生物种的评价选择、水土保持植被种防侵蚀机理、水土保持植被措施的配置以及水土保持植被建造技术等四个方面,并且对四个方面的内容进行了详细地总结分析.     

差分GPS技术在谷物测产系统中的应用

目前，在谷物测产系统中，开始应用动态差分GPS技术建立产量计算模型和小区产量分布图，以获得农作物小区产量信息。为此，介绍了GPS定位原理、方法以及动态差分GPS技术，并进行了差分定位试验和分析。差分GPS在谷物产量图生成中的应用表明，差分GPS技术能满足田间谷物测产的需要。     

缺省值问题中一种新的比较补充方法的方法

讨论了当缺省值问题中有多种补充方法时,从补充完整样本的损失的角度,并引进了统计决策理论来比较这些补充方法.当补充风险r(X ,X)=∫∫f(X (x)-x)dPXmisθxmis)dPθ(xobs)在决策空间是最小时,相应的补充方法就是容许决策法则.     

半线性抛物方程时间离散间断伽辽金方法的误差估计

本文讨论一类半线性方程间断伽辽金方法的时间离散格式，对ｑ＝０给出了先验误差估计，并将结果应用于一个抛物变分不等式。     

用多项式辅助估计动物的生长模型参数

本文尝试用多基工辅助估计生物学基础模型参数，并根据辅助对象划分为辅助微分模型和直接辅助参数估计法，拟合试验表明，辅助拟合法简便易懂，拟合精度高，尤其是直接辅助参数估计法的拟合效果接近Ｍａｒｑｕａｒｄｔ法。     

Observations on the natural history of the Gulf of Mexico sturgeon (Acipenser oxyrinchus de sotoi Vladykov 1955) in the Suwannee River, southeastern United States

From 1986 to 1994, we collected 3,098 Gulf of Mexico sturgeon (Acipenser oxyrinchus de sotoi) during their spring migration from the Gulf of Mexico to the Suwannee River, Florida. We estimated population size and described migratory and seasonal growth patterns of sturgeon in the Suwannee River, using data from tag returns, movement of ultrasonic-lagged fish and weight records. Population size estimates for 3.0- to 81.0-kg Gulf of Mexico sturgeon in the Suwannee River ranged from 1,504 to 3,066 fish. Sturgeon migrated from the Gulf of Mexico into the Suwannee River from mid-February to early May. Fish moved upstream and remained within a 2-km upstreamdownstream “home” area. These sites were closely associated with undenvater springs that discharge into the river. Sturgeon migrated downstream and into the Gulf of Mexico in October and November. In the Gulf of Mexico, ultrasonic-tagged fish were located in the Suwannee Sound area just north of Cedar Key, Florida. On an annual basis, fish gained an average of 20% of their body weight while in the Gulf of Mexico and lost about 12% of their weight during their stay in the Suwannee River. We observed movement of tagged sturgeon between the Suwannee and Apalachicola Rivers.     

Heritability estimates and genetic correlations of various production and reproductive traits of different grades of dairy cattle reared under subtropical condition

Inheritance of economic traits and their genetic correlation was studied in different breeds and their various grades (crossbred’s cattle) under the subtropical condition. Data on principal parameters comprising 10 years, that is 2004–2014, were utilized for the present study. Different grades of dairy cows comprising Holstein Friesian (HF), Sahiwal x Friesian (SxHF), Jersey (J), Jersey x Achai (JxAC) and Achai (AC) were included in the study. Heritability estimates and genetic correlations of some important productive and reproductive traits were worked out. Heritability estimates of certain economic traits were found to be: birthweight, 0.32 ± 0.181; age at maturity, 0.11 ± 0.136; age at first calving, 0.19 ± 0.162; days open, 0.09 ± 0.121; calving interval, 0.14 ± 0.211; dry period, 0.11 ± 0.124; lactation length, 0.04 ± 0.212 and lactation yield, 0.46 ± 0.206. Genetic correlation showed that body weight was significantly and positively correlated with lactation length (0.30) and lactation yield (0.81), while negatively correlated with age at maturity, age at first calving, days open, calving interval and dry period (?0.09, ?0.07, ?0.16, ?0.34 and ?0.002, respectively). Calving interval was positively and significantly correlated with the dry period (0.56), lactation length (0.72) and lactation yield (0.37). Moderate to higher heritability estimates with adequate genetic variance was found for body weight and lactation yield. The moderate to higher heritability estimates of birthweight in the present study revealed that this important trait might be considered in selection criteria.     

茄子果顶形状数据采集方法比较和遗传分析

以圆顶茄子和尖顶茄子为亲本构建6世代群体(P_1、P_2、F_1、BC_1P_1、BC_1P_2、F_2),在春露地和秋大棚两个茬口分别种植6世代群体,利用目测法和Tomato Analyzer软件分析法采集茄子果顶形状数据,应用植物数量性状主基因+多基因混合遗传模型多世代联合分析方法,对茄子果顶形状进行遗传分析。结果表明:目测法和软件法都可以用来描述茄子果顶形状,Tomato Analyzer软件分析法获取的果顶数据计算出的AIC值完整性好、适应性检测中的统计量差异显著个数少,对茄子果顶形状的数据测量更为准确,更加适用于茄子果顶形状的采集。茄子果顶形状表现为数量性状,受2对加性-显性-上位性主基因控制,同时也受环境条件的影响。在分离群体中F_2群体主基因遗传率高、稳定性好,主基因遗传率达到72%以上,育种过程中适合在F_2群体进行果顶形状的选择。