基于小波变换和曲线拟合法的柴油机故障诊断

为了对柴油机故障类型进行准确诊断,对柴油机缸盖振动信号进行特征提取,所测取的信号通过小波变换提取时域、频域特征参数,得到相应的拟合曲线并计算多项式系数。设定两种常见故障,通过比较其小波变换拟合多项式系数与标准模式间的距离,从而判断出故障类型。经过验证,所判断出的故障类型正好为所设定的故障,由此表明该方法具有很大的优越性。     

Fitting room or selling room? Millennial female consumers’ dressing room experiences

As retail experiences have become more important to the modern consumer, the store environment has taken on greater significance. The store environment is especially of great significance to the millennial consumer. These consumers tend to spend more time in the fashion retail store, while their expenditure on fashion items increases on a yearly basis. The dressing room must be seen as the clothing retailer's selling room – the place where the retail environment plays an immense role with regard to a consumer's cognitions, emotions and purchasing behaviour. The purpose of this study was to explore and describe young millennial clothing consumers' Functional, aesthetic, emotional and symbolic dressing room experiences. A qualitative research strategy was followed. Two unstructured interviews were held with 15 participants. Participants had to take photos of retailers' dressing rooms before the second interview. A photo‐elicitation technique was employed during the second interview. Findings revealed that participants had specific expectations with regard to the functionality and aesthetics of the dressing room, as well as with regard to the symbolic messages and the emotions that they expected to experience. If the dressing room did not meet their expectations they got disappointed, experienced negative emotions and thoughts and the need to leave the dressing room. The behavioural response of avoidance strongly came to the forth. Findings of this research point to the importance of the dressing room as part of the retail experience and have implications for consumer specialists and retailers.     

沪深300ETF 拟合效果的比较研究--基于华泰柏瑞沪深和嘉实沪深300ETF

文章比较分析了沪深300股指期货套期保值所采用的几种现货工具：上证180ETF 或上证50ETF 和深证100ETF 构建的 ETF 组合、华泰柏瑞沪深300ETF、嘉实沪深300ETF,实证检验了两只沪深300ETF 以及 ETF 组合对沪深300股指期货的拟合效果的差异,为现货工具的选择给出建议,并为后续对沪深300ETF 的套期保值的研究做出铺垫。     

物流设施选址问题中时间满意度函数的定义及应用

建立了顾客对等待时间的满意度与物流设施和需求点间的距离之间的函数关系,描述了时间满意度函数的拟合方法并给出了函数的拟合原则,最后以集覆盖问题为例说明了时间满意度函数的应用。     

行为域和环境域匹配的模型分析

R·R·布莱克和J·S·穆顿的管理方格理论认为,由于管理者对人或生产的关心程度不同,每个管理者有自己的管理方式.我们认为,管理者的管理方式并非仅限一种,而是管理方格中的一个区域,即行为域;同样地,企业对管理方式的需求也是方格中的一个区域,即环境域.行为域和环境域可以相互影响,相互吸引,进而扩大其吻合的部分,二者的吻合程度反映了管理者与企业匹配的合理程度,提高吻合度需要管理者选择合适的企业和最佳的管理方式、努力改造自己和适度改造企业.     

高等教育学费问题探讨

对高等教育收费水平的现状进行了分析,预测了收费水平的基本增长趋势。并从影响学费的相关因素的角度对学费水平进行了系统分析,结合办学成本、政府拨款和农村居民可支配收入给出了可行性报告和建议。     

资产结构与企业经营绩效的最优化配置研究——以中国纺织机械股份有限公司为例

本文认为,较之资本结构,资产结构的研究更具实际应用价值和普适意义,它们才是创造公司价值和抵御各项风险的源泉。基于此,本文试图从逻辑和实证两个角度评价资产结构与企业绩效之间的关系,并希望通过评价实证结论的相关性程度,来求得各变量之间的函数方程式。在此基础上,本文再分别进行各变量的曲线拟合,试图通过在建立拟合方程模型的基础上,求出其最优资产配置值。     

The association between two random elements: A complete characterization and odds ratio models

For random elements X and Y (e.g. vectors) a complete characterization of their association is given in terms of an odds ratio function. The main result establishes for any odds ratio function and any pre-specified marginals the unique existence of a corresponding joint distribution (the joint density is obtained as a limit of an iterative procedure of marginal fittings). Restricting only the odds ratio function but not the marginals leads to semi-parmetric association models for which statistical inference is available for samples drawn conditionally on either X or Y. Log-bilinear association models for random vectors X and Y are introduced which generalize standard (regression) models by removing restrictions on the marginals. In particular, the logistic regression model is recognized as a log-bilinear association model. And the joint distribution of X and Y is shown to be multivariate normal if and only if both marginals are normal and the association is log-bilinear.Acknowledgements The author thanks both referees for their helpful comments which improved the first draft of the paper.     

基于多项式拟合频率重构的物理不可克隆函数优化

近年来硬件安全不断受到挑战,具有不可预测性、随机性等特性的环形振荡器物理不可克隆函数（Ring Oscillator Physical Unclonable Function,RO PUF）可作为硬件安全重要的加密密钥方式,但通常原始RO PUF不满足加密密钥对随机性的要求。因此,提出了基于多项式拟合频率重构的PUF优化方法。首先,实现RO电路的硬宏设计并在现场可编程门阵列(Field Programmable Gate Array,FPGA)上进行实例化,从而获得RO阵列的频率数据;其次,针对原始响应的随机性较差的情况,通过统计分析其分布特征,利用多项式拟合法优化重构RO阵列频率;最后,采用熵密度值评估RO PUF响应的随机性。选用型号为Xilinx Artix 7103的FPGA板进行实验测试评估,结果表明所提方法不仅比原始RO PUF响应的随机性强,而且与随机补丁混合法(Random Patch Mixer,RPM)和基于回归的熵蒸馏法相比也具备更好的随机性。     

Pricing equity options everywhere

Finite difference methods are a popular technique for pricing American options. Since their introduction to finance by Brennan and Schwartz their use has spread from vanilla calls and puts on one stock to path-dependent and exotic options on multiple assets. Despite the breadth of the problems they have been applied to, and the increased sophistication of some of the newer techniques, most approaches to pricing equity options have not adequately addressed the issues of unbounded computational domains and divergent diffusion coefficients. In this article it is shown that these two problems are related and can be overcome using multiple grids. This new technique allows options to be priced for all values of the underlying, and is illustrated using standard put options and the call on the maximum of two stocks. For the latter contract, I also derive a characterization of the asymptotic continuation region in terms of a one-dimensional option pricing problem, and give analytic formulae for the perpetual case.