单载波载噪比估计的实现

针对卫星通信中对信标载噪比估算的需求,提出一种单载波载噪比估计的实现方法。分析了载波恢复的频差估计算法的性能,实现了最大似然估计载波载噪比,并仿真了估计误差值曲线。提高了载噪比估计的性能,减少了对星的时间,提高对星的精度。     

基于半定松弛的长码DSSS信号扩频波形估计

针对非合作通信中的长码DSSS信号,提出了一种基于半定松弛的扩频波形估计方法,并在确定信号模型下推导了扩频波形估计的CRB.首先推导了长码DSSS信号扩频波形的极大似然估计,由于该极大似然估计为非凸的组合优化问题,提出通过松弛约束条件将其转化为具有多项式计算复杂度的半定规划问题,实现对该极大似然估计问题的近似求解.仿真表明本文提出方法性能优于现有方法,并随着信噪比的提高逐渐逼近CRB.     

浅谈公路建设项目概预算编制中的问题

结合公路建设项目的特点，根据自身的实践经验，就公路工程造价概、预算编制中容易出现的问题作了总结，分析了问题产生的原因，提出了相应的预防措施，以提高概预算编制和审查质量。     

多指标考核中的分析模型与意义

本文通过两个模糊数学模型把考核信息进行综合处理,为考核提供了更多更有意义的分析结果。     

传感器输出特征线性化的稳健算法

利用最小一乘估计的稳健性 ,给出了传感器输出特征线性化的特征直线的稳健估计。该方法在稳健性方面明显优于最小二乘估计 ,更有效地刻划了传感性输出特征的本质     

神经网络在GPS向量网抗差估计中的应用分析

神经网络被引入GPS向量网的平差处理时，网络训练数据由于在测量时各因数的干扰多少都有噪声或异常值掺入。为了使网络具有更好抵抗粗差的能力，文中根据稳健统计有关原理，针对神经网络论证了一种较好的抗差估计函数作为网络目标函数。以函数逼近来说明平差所采用的模型与神经网络处理时的异同，理论分析和实验证明了神经网络的抗粗差能力。     

Excel环境下水利工程的概(预)算编制

水利工程概预算必须遵照国家规定的编制办法和固定的格式(表格)进行。利用Excel(电子表格)在计算机上进行编制和计算,能够满足编制办法要求的表格的形式,计算过程完全是人、机交互式对话界面,本文结合水利工程招投标报价实例,介绍了Excel环境下水利工程概预算的计算方法。结果表明,该方法能迅速准确地进行工程造价计算,是一种有效的水利工程概预算编制方法。     

How to Choose the Proper Sample Size

Two simple proof-load testing procedures are suggested to estimate the correlation between two variables that can individually only be determined destructively. The first procedure assumes that the means and variances of the variables are known. The second testing procedure is more flexible and requires no prior information. By assuming that the variables have a bivariate normal distribution and considering only the number of units that fail at each proof-load, we determine the maximum likelihood estimate for the correlation coefficient. Theoretical and simulation results compare favorably with previously suggested more complicated procedures and guide the practitioner in appropriate choices for the proof-load levels.     

A Process Model for Approximating the Production Costs of the Fermentative Synthesis of Sophorolipids

Sophorolipids are microbial glycolipids that possess surfactant-type properties. Sophorolipids have been tested successfully in a number of potential industrial and niche applications but are generally acknowledged to require higher production costs when compared to petroleum-based surfactants. The objective of this study was to develop a process economic model for the fermentative synthesis of sophorolipids using contemporary process simulation software and current reagent, equipment, and supply costs, following current production practices. Glucose (Glc) and either high oleic sunflower oil (HOSO) or oleic acid (OA) were used as feedstocks and the annual production capacity of the plant was set at 90.7 million kg/year with continuous operation of 24 h a day for 330 days per year. Major equipment costs were calculated to be US$17.1 million but other considerations such as capital, labor, material and utilities costs were also included. The single greatest contributor to the overall production/operating cost was raw materials, which accounted for 89 and 87 % of the total estimated production expenditures for the HOSO and OA-based fermentations, respectively. Based on this model and yields of 100 g/L, the cost of large-scale sophorolipid synthesis via fermentation from Glc:HOSO was calculated to be US$2.95/kg ($1.34/lb) and from Glc:OA to be US$2.54/kg ($1.15/lb). The model is flexible and can be adjusted to reflect changes in capital, production and feedstock costs as well as changes in the type of feedstocks used.     

Modeling preventive maintenance using subjective data

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