上海内河集装箱运输发展的问题探讨

通过对长三角地区“十一五”及“十二五”期间建设或规划建设的高等级内河航道网络的介绍,分析上海地区现今内河集装箱运输还难得一见的主要原因.结合上海内河航道建设的实际情况和内河航运的特点,提出了加快上海内河集装箱运输发展的相关建议,以供探讨.     

一类三角矩阵的特征值反问题

对一类奇阶上三角矩阵的特征值反问题进行研究,通过两个给定特征对(λ,x),(μ,y)对矩阵的存在性及唯一性的条件进行讨论,在满足条件的前提下进行求解并给出表达式,通过数值例子验证算法的可行性.     

Dynamic stability metrics for the container loading problem

The Container Loading Problem (CLP) literature has traditionally evaluated the dynamic stability of cargo by applying two metrics to box arrangements: the mean number of boxes supporting the items excluding those placed directly on the floor (M1) and the percentage of boxes with insufficient lateral support (M2). However, these metrics, that aim to be proxies for cargo stability during transportation, fail to translate real-world cargo conditions of dynamic stability.In this paper two new performance indicators are proposed to evaluate the dynamic stability of cargo arrangements: the number of fallen boxes (NFB) and the number of boxes within the Damage Boundary Curve fragility test (NB_DBC). Using 1500 solutions for well-known problem instances found in the literature, these new performance indicators are evaluated using a physics simulation tool (StableCargo), replacing the real-world transportation by a truck with a simulation of the dynamic behaviour of container loading arrangements.Two new dynamic stability metrics that can be integrated within any container loading algorithm are also proposed. The metrics are analytical models of the proposed stability performance indicators, computed by multiple linear regression. Pearson’s r correlation coefficient was used as an evaluation parameter for the performance of the models. The extensive computational results show that the proposed metrics are better proxies for dynamic stability in the CLP than the previous widely used metrics.     

基于WATV去噪的冲击特征提取方法在高速列车轴承故障诊断中的应用

提取高速列车轴承故障振动信号中的冲击特征,可以有效地对其进行故障诊断。利用"小波-全变差(Wavelet-Total Variation,WATV)"算法能够对信号进行稀疏引导的特点,提出了基于WATV去噪的冲击特征提取方法。该算法针对含噪声冲击特征的提取问题构建了目标优化函数,该函数融合了冲击特征的保真度度量算子以及惩罚因子。利用凸优化理论可对目标函数进行求解,从而增强信号在小波域和时域的稀疏性,使得特征提取结果最优化。通过构造一仿真信号对WATV算法的有效性进行了验证,并将该方法应用于高速列车齿轮箱轴承故障诊断中。结果表明,该方法能够很好地提取出信号中的冲击特征,并且频谱中的故障表征明显,能够有效地应用于高速列车轴承故障诊断中。     

平面一阶非线性椭圆型方程组的Riemann边值问题

本文研究平面非线性椭圆型方程组的Riemann边值问题:在假设条件(A1)、(A2)、(A3)之下,证明了该问题存在唯一的解1相似文献   

Two Bandwidth Packing Algorithms for the Centralized Wireless Network and Their Average-case Analysis

This paper presents a detail analysis of two bandwidth packing algorithms, used for processing connection requests in the centralized wireless network. Each call comes with a specific bandwidth request. A request can be satisfied only if there is sufficient bandwidth available during resource scheduling and allocation. Unsatisfied requests were held in a queue. The metric of bandwidth utilization ratio was used to quantify the performance of our algorithms. By theoretical analysis, our algorithms can improve the average bandwidth usage ratio significantly, about 8%~10% without adding much computation complexity. Moreover, our algorithms outperform next fit with fragmentation (NFF) algorithm when the bandwidth resource is scarce. In this paper, the contributions follows: Introducing bandwidth packing problem into wireless network; Proposing two new bandwidth packing algorithms for wireless network where the complicate scheduling algorithms are prohibited; Studying the average performance of our algorithms mathematically, which agree well with the simulation results.     

竞争中二度价格歧视研究

运用博弈论知识，采用定量分析方法，系统地讨论了二度价格歧视条件下竞争厂商的利润最大化条件．首先讨论了二度价格歧视利润最大化条件，然后将此条件加以推广．接着分别研究了线性需求函数和非线性需求函数情形下的利润最大化问题．针对上述问题，均给出了严谨的理论分析和有关计算公式．     

浅谈农村公路建设存在的问题与对策

针对当前农村公路建设、养护管理现状和存在的问题,提出一些建议,供同行参考.     

����ʽ����Ż��㷨Ч�ʵĸĽ��о�

以车辆调度问题为实例引出一种新的组合优化算法，并与原有的方法进行比较，说明新方法可以有效地抑制组合爆炸，极大地提高算法寻优效率.然后，本文用数学方法来证明该新方法再寻优上的正确性，最后根据两种不同算法编写各自对应的程序，用实际运行的结果来验证新算法带来的效率的提高.     

Regularization Method to the Parameter Identification of Interfacial Heat Transfer Coefficient and Properties during Casting Solidification

The accurate material physical properties, initial and boundary conditions are indispensable to the numerical simulation in the casting process, and they are related to the simulation accuracy directly. The inverse heat conduction method can be used to identify the mentioned above parameters based on the temperature measurement data. This paper presented a new inverse method according to Tikhonov regularization theory. A regularization functional was established and the regularization parameter was deduced, the Newton-Raphson iteration method was used to solve the equations. One detailed case was solved to identify the thermal conductivity and specific heat of sand mold and interfacial heat transfer coefficient (IHTC) at the meantime. This indicates that the regularization method is very efficient in decreasing the sensitivity to the temperature measurement data, overcoming the ill-posedness of the inverse heat conduction problem (IHCP) and improving the stability and accuracy of the results. As a general inverse method, it can be used to identify not only the material physical properties but also the initial and boundary conditions' parameters.