基于ARM的机车交直流接地故障诊断系统

针对目前机车电气线路接地故障解决方法的不足,提出一种基于ARM嵌入式系统的机车交直流接地故障诊断系统,重点介绍了系统的工作原理和硬软件设计;该系统采用精确的检测手段,独特的分析方法,能够快速、准确的定位接地故障点及故障类型,灵活多样的通讯方式,便于故障信息的储存和上传,以及机务段的统一管理;经实验证明,该系统检测精度高,运行稳定,具有很大推广价值。     

Feature scaling for kernel fisher discriminant analysis using leave-one-out cross validation

Kernel fisher discriminant analysis (KFD) is a successful approach to classification. It is well known that the key challenge in KFD lies in the selection of free parameters such as kernel parameters and regularization parameters. Here we focus on the feature-scaling kernel where each feature individually associates with a scaling factor. A novel algorithm, named FS-KFD, is developed to tune the scaling factors and regularization parameters for the feature-scaling kernel. The proposed algorithm is based on optimizing the smooth leave-one-out error via a gradient-descent method and has been demonstrated to be computationally feasible. FS-KFD is motivated by the following two fundamental facts: the leave-one-out error of KFD can be expressed in closed form and the step function can be approximated by a sigmoid function. Empirical comparisons on artificial and benchmark data sets suggest that FS-KFD improves KFD in terms of classification accuracy.     

常规光纤非线性对色散补偿光纤位置的影响

通过数值计算的方法分析了色散、自相位调制和激光器啁啾等因素对１０Ｇｂ／ｓ１００ｋｍＧ．６５２光纤通信系统的综合效应。对１０Ｇｂ／ｓＧ．６５２光纤系统中用色散补偿光纤（Ｄｉｓｐｅｒｓｉｏｎ Ｃｏｍｐｅｎｓａｔｉｏｎ Ｆｉｂｅｒ,即ＤＳＦ）的两种方案进行了比较,然后简单讨论了色散补偿光纤在密集波分复用（ＤＷＤＭ）中的应用,最后给出通过以上分析得出的结论。     

甚小孔径卫星（VSAT）的数据传输应用

简单分析了甚小孔径卫星通信的技术特点和优缺点。重点讨论用它来解决数据传输问题,通过举例对目前采用ＶＳＡＴ卫星通信解决数据传输问题的技术做进一步的讨论。     

4-乙烯基环己烯环氧化反应研究

分别以单过氧马来酸、单过氧邻苯二甲酸、过氧三氯乙酸以及过氧乙酸作环氧化试剂，对４－乙烯基环己烯环氧化反应作了研究，并从分子结构的角度，阐明了４－乙烯基环己烯在环氧化反应中所表现出的选择性     

宾馆入口广场环境景观设计探析

宾馆是城市的特殊景观,是城市文化的重要体现。作为宾馆门户空间的入口广场,其环境景观设计的好坏直接影响着整个宾馆的形象和品位。以开封黄河迎宾馆入口广场环境景观设计方案为例,探讨了影响宾馆入口空间景观塑造的主要因素—植物景观、水景景观、小品景观、铺地景观的设计方法和要点,提出要在满足功能需求的基础上,综合运用园林要素塑造具有地域特征和文化内涵的宾馆门户空间。 关键词：宾馆;入口广场;景观设计;要素;功能;文化 中图分类号：TU986 文献标识码：A     

Globally stable adaptive robust tracking control using RBF neural networks as feedforward compensators

In previous adaptive neural network control schemes, neural networks are usually used as feedback compensators. So, only semi-globally uniformly ultimate boundedness of closed-loop systems can be guaranteed, and no methods are given to determine the neural network approximation domain. However, in this paper, it is showed that if neural networks are used as feedforward compensators instead of feedback ones, then we can ensure the globally uniformly ultimate boundedness of closed-loop systems and determine the neural network approximation domain via the bound of known reference signals. It should be pointed out that this domain is very important for designing the neural network structure, for example, it directly determines the choice of the centers of radial basis function neural networks. Simulation examples are given to illustrate the effectiveness of the proposed control approaches.     

奇性函数的加权Stancu算子逼近

作为算子逼近中的一种重要类型,Bernstein算子对于函数的逼近无论在逼近论还是计算数学中都具有非常重要的地位。该文研究Bernstein算子的更一般推广——Stancu算子,考虑了Stan-cu算子对在端点处具有奇性的函数的加权逼近,并通过Ditzian-Totik光滑模ω2φ（f,δ）对该算子的逼近阶作出具体估计。     

基于NPS的常微分方程OBVP的研究

根据样条函数中基函数的特殊选取,构造出了一类新的非多项式样条函数,用来求解常微分方程OBVP的边值问题.给出求解的递推公式,并进行了相应的误差分析,结果显示该方法的局部截断误差为O（h6）.     

Flotation performances of polymorphic pyrrhotite

The floatability of different crystalline structures of pyrrhotite (monoclinic and hexagonal) was studied. It is shown that the floatability of monoclinic and hexagonal has obvious difference, and that the flotation recovery of monoclinic pyrrhotite is larger than that of hexagonal pyrrhotite using different collectors. When butyl dithiophosphate is used as the collector, the recovery is larger than that by sodium butyl xanthate and sodium diethyl dithiocarbamate. At the pH values ranging from 6 to 9, monoclinic pyrrhotite can be floated well, and the flotation recovery is higher than 90%. Monoclinic and hexagonal pyrrhotites are more easily activated by Cu²⁺ in acidic conditions than in alkaline conditions. But Cu²⁺ cannot activate hexagonal pyrrhotite using sodium diethyldithiocarbamate as the collector. By the measurement of contact angle, it is indicated that monoclinic and hexagonal pyrrhotites float well and are easily activated by Cu²⁺ when dithiophosphate is used as the collector. Using sodium diethyl dithiocarbamate as a collector, the relationship between potential and pH range for pyrrhotite flotation is established. At pH 5, the optimal potential range for flotation of monoclinic pyrrhotite is about 125–580 mV (vs SHE), with the maximum flotation occurring at about 350 mV (vs SHE); the optimal potential range for flotation of hexagonal pyrrhotite is 200–580 mV (vs SHE), with the maximum flotation occurring at about 300 mV (vs SHE).