高速公路项目采购成本管理的原则与方法

本文针对高速公路项目详细阐述了其采购成本的原则和方法。     

基于稳健关联向量回归的黑液波美度软测量

针对造纸工业碱回收蒸发工段黑液波美度不易在线实时测量的现状,提出一种基于稳健关联向量回归的软测量方法,建立黑液波美度的软测量模型,实现黑液波美度的在线测量。稳健关联向量回归方法通过最大化一个建立在稳健子集上的似然函数得到模型的参数,同时保证回归的稳健性。构造了迭代算法来计算稳健关联向量回归,在优化超参数的同时,寻找稳健子集。实验结果表明,用该方法建立波美度软测量模型不仅是可行的和有效的,而且能够克服异常点的影响。     

Fast Fractal Image Encoding Using an Improved Search Scheme

As fractal image encoding algorithms can yield high-resolution reconstructed images at very high compression ratio, and therefore, have a great potential for improving the efficiency of image storage and image transmission. However, the baseline fractal encoding algorithm requires a great deal of time to complete the best matching search between the range and domain blocks, which greatly limits practical applications of the algorithm. In order to solve this problem, a necessary condition of the best matching search based on an image feature is proposed in this paper. The proposed method can reduce the search space significantly and excludes the most inappropriate domain blocks for each range block before carrying out the best matching search. Experimental results show that the proposed algorithm can produce good quality reconstructed images and requires much less time than the baseline encoding algorithm. Specifically, the new algorithm can speed up encoding by about 85 times with a loss of just 3 dB in the peak signal to noise ratio (PSNR), and yields compression ratios close to 34.     

大柔性飞机着陆响应弹性机体模型

对大展弦比、小弦长差、细窄机身结构特征的飞机,建立了着陆撞击分析时的自由-自由梁弹性机体模型,给出了自由-自由梁弯曲振动的一个近似解,并与实测值进行了对比,结果表明这个近似解具有较大的适用性.介绍了飞机机体刚体模态和一阶弯曲振动模态的飞机机体二质量块等效模型,研究了最大起飞质量及最小飞行质量2种情形下着陆时的机体弹性特征,探讨了弹性飞机起落架设计与刚性飞机相比在技术上的重大变化,为起落架设计中考虑飞机弹性影响提供了简化模型、直观概念和可靠依据.     

花粉母細胞中染色質穿壁轉移現象的普遍性与一般性的补充資料

1956年,我们曾用三种不同的方法(醋酸胭脂红塗片法、压碎法和石腊切片法)观察了属于六科十属十九种或品种的花粉母细胞,發现在不同的栽培条件下,都能看到在花粉母細胞中有染色質穿壁转移现象。因此,我們認为这种现象是相当普遍地存在于植物界的一种正常现象。最近,我们为了作好深入一步研究的准备工作,又用同样的三种方法观察了分隶于十六科二十属的二十二种植物[蕎麦(Fagopyrum esculentum Mo-     

非线性LTS稳健估计方法

为使原始LTS(least trimm ed squares)方法能够处理非线性问题,研究非线性LTS稳健估计方法。说明该方法的解一定是部分观测值的非线性最小二乘估计。该方法可通过求解非线性最小二乘问题得到确切解。基于MM EA(m in im um m ax im um exchange a lgorithm)算法和非线性最小二乘技术,构建求解非线性LTS估计近似解的算法。仿真结果表明非线性LTS估计方法能够同时抵抗来自X方向和Y方向的多个异常,与传统方法相比具有更好的稳健性。     

两输入非线性前馈系统的镇定方法

为了便于构造两输入非线性前馈系统的镇定控制器,通过变换构造出与原系统等价的复数域低维单输入非线性前馈系统,再利用已有的单输入系统的控制方法对该等价系统设计一个复数域镇定控制器,采用逆变换得到原系统的两个镇定控制器,提出了将原系统转化为等价系统后再进行设计的镇定方法。用Lyapunov稳定性定理证明了闭环控制系统状态的渐进稳定性。结果表明:等价系统比原系统具有更少的输入和更低的维数,基于等价系统的设计方法降低了系统的分析难度,简化了控制器的设计步骤。     

Computing Nonlinear LTS Estimator Based on a Random Differential Evolution Strategy

Nonlinear least trimmed squares （NLTS） estimator is a very important kind of nonlinear robust estimator, which is widely used for recovering an ideal high-quality signal from contaminated data. However, the NLTS estimator has not been widely used because it is hard to compute, This paper develops an algorithm to compute the NLTS estimator based on a random differential evolution （DE） strategy. The strategy which uses random DE schemes and control variables improves the DE performance. The simulation results demonstrate that the algorithm gives better performance and is more convenient than existing computing algorithms for the NLTS estimator. The algorithm makes the NLTS estimator easy to apply in practice, even for large data sets, e.g. in a data mining context.     

Soft Sensing of Overflow Particle Size Distributions in Hydrocyclones Using a Combined Method

Precise, real-time measurements of overflow particle size distributions in hydrocyclones are necessary for accurate control of the comminution circuits. Soft sensing measurements provide real-time, flexible, and low-cost measurements appropriate for the overflow particle size distributions in hydrocyclones. Three soft sensing methods were investigated for measuring the overflow particle size distributions in hydrocyclones. Simulations show that these methods have various advantages and disadvantages. Optimal Bayesian estimation fusion was then used to combine three methods with the fusion parameters determined according to the performance of each method with validation samples. The combined method compensates for the disadvantages of each method for more precise measurements. Simulations using real operating data show that the absolute root mean square measurement error of the combined method was always about 2% and the method provides the necessary accuracy for beneficiation plants.     

混合Euler图的特征性质

本文对任意混合图 M 建立相伴运输网络 N_M 的概念,并以此给出 M 是混合 Euler 图的充要条件。这结果与文献中同类结果相比,具有更大的实用性。