一种低复杂度振动信号检测分类算法

低复杂度的振动信号常规峰度检测算法只能检测人员入侵行为,不能检测车辆入侵行为.根据噪声数据与车辆入侵数据特点,结合时间窗和马尔柯夫过程概念,提出了基于改进峰度的振动信号检测分类算法.该算法引入背景噪声的平均能量,利用包含比例因子P和异常突变阈值r的分段函数代替信号能量,可以避免毛刺信号干扰,检测并区分人员入侵和车辆入侵而不需要任何先验条件.试验表明,该算法具有复杂度低,资源要求低,漏警率低的特点.     

分功率因数电能表的设计

设计了一种分功率因数电能表。该电能表是采用实时功率因数调整电费方法的一种新型电子式电能表,目的是解决目前所使用的月平均功率因数法不能真实反映用户实时功率因数的缺陷,并利用经济杠杆的手段激励用户改善功率因数,从而达到提高电网运行质量的目的。     

Quantifying requirements volatility effects

In an organization operating in the bancassurance sector we identified a low-risk IT subportfolio of 84 IT projects comprising together 16,500 function points, each project varying in size and duration, for which we were able to quantify its requirements volatility. This representative portfolio stems from a much larger portfolio of IT projects. We calculated the volatility from the function point countings that were available to us. These figures were aggregated into a requirements volatility benchmark. We found that maximum requirements volatility rates depend on size and duration, which refutes currently known industrial averages. For instance, a monthly growth rate of 5% is considered a critical failure factor, but in our low-risk portfolio we found more than 21% of successful projects with a volatility larger than 5%. We proposed a mathematical model taking size and duration into account that provides a maximum healthy volatility rate that is more in line with the reality of low-risk IT portfolios. Based on the model, we proposed a tolerance factor expressing the maximal volatility tolerance for a project or portfolio. For a low-risk portfolio its empirically found tolerance is apparently acceptable, and values exceeding this tolerance are used to trigger IT decision makers. We derived two volatility ratios from this model, the π-ratio and the ρ-ratio. These ratios express how close the volatility of a project has approached the danger zone when requirements volatility reaches a critical failure rate. The volatility data of a governmental IT portfolio were juxtaposed to our bancassurance benchmark, immediately exposing a problematic project, which was corroborated by its actual failure. When function points are less common, e.g. in the embedded industry, we used daily source code size measures and illustrated how to govern the volatility of a software product line of a hardware manufacturer. With the three real-world portfolios we illustrated that our results serve the purpose of an early warning system for projects that are bound to fail due to excessive volatility. Moreover, we developed essential requirements volatility metrics that belong on an IT governance dashboard and presented such a volatility dashboard.     

Social network,social trust and shared goals in organizational knowledge sharing

The aim of our study was to further develop an understanding of social capital in organizational-knowledge-sharing. We first developed a measurement tool and then a theoretical framework in which three social capital factors (social network, social trust, and shared goals) were combined with the theory of reasoned action; their relationships were then examined using confirmatory factoring analysis. We then surveyed of 190 managers from Hong Kong firms, we confirm that a social network and shared goals significantly contributed to a person's volition to share knowledge, and directly contributed to the perceived social pressure of the organization. The social trust has however showed no direct effect on the attitude and subjective norm of sharing knowledge.     

Explaining IS continuance in environments where usage is mandatory

Several research efforts over the last decade have attempted to explain user acceptance in mandated environments. This research is an attempt in the same direction. It addresses users’ satisfaction in mandated environments to further contribute to our understanding of how we can manage mandated use of information systems (IS) effectively beyond initial adoption. To better explain users’ IS continuance a revised post-acceptance model is proposed and empirically tested using the structural equation modelling technique. The results demonstrate the reliability and validity of the proposed measurement model and further demonstrate that confirmed expectations and ease of use perceptions explain 61% of the users’ satisfaction in this setting. Our findings have important implications for the management of users in mandated environments as well as for further research in the area of mandated use. To that end, we offer directions for future research.     

Extended stochastic gradient identification algorithms for Hammerstein–Wiener ARMAX systems

An extended stochastic gradient algorithm is developed to estimate the parameters of Hammerstein–Wiener ARMAX models. The basic idea is to replace the unmeasurable noise terms in the information vector of the pseudo-linear regression identification model with the corresponding noise estimates which are computed by the obtained parameter estimates. The obtained parameter estimates of the identification model include the product terms of the parameters of the original systems. Two methods of separating the parameter estimates of the original parameters from the product terms are discussed: the average method and the singular value decomposition method. To improve the identification accuracy, an extended stochastic gradient algorithm with a forgetting factor is presented. The simulation results indicate that the parameter estimation errors become small by introducing the forgetting factor.     

带退化因子的人工代谢算法在多对象物流配送优化中的应用

在多对象优化的物流配送中,需要对配送对象实行均衡调度。本文提出了一种含退化因子的人工代谢算法。每一种配送对象对应了不同的代谢底物,每一种配送对象的优先级对应了相应的催化酶,每一次配送对应一次代谢过程。为了降低代谢算法的复杂度,完成配送任务后,初始化时形成的催化酶需要有规律地退出代谢体系。通过对代谢算子等参数的分析,为人工酶设立了不同等级的退化因子。根据对酶优先级的辨识,按照代谢优化的进程,使已完成寻优搜索的代谢路径有序地退出本次代谢网络,提高整个代谢网络运行效率,为后续的物流配送路径缩小搜索空间,实现多对象配送过程的优化。     

风/光互补发电场优化设计模型

针对复杂的风/光互补发电场优化设计问题,首次提出了一种新的风/光互补发电场优化设计模型.在分析了现有研究的基础上,给出了适合于风/光互补发电场部件发电量计算的计算模型,归纳了设计时各部件的数量和类型选择的约束关系,最后综合给出了一种新的适合于风/光互补发电场优化设计的模型.     

时间序列季节调整方法在中国的发展:PBC版X-12-ARIMA

中国人民银行(PBc)版X-12-ARIMA软件是基于中国特点而定制的时间序列季节调整软件.通过总结时间序列季节调整方法的特点以及相应软件在国外的发展,针对我国应用的特点,尤其是春节因素的考虑,在解剖X-12-ARIMA方法原理的基础上,在春节因素计算方法、软件应用界面以及用户使用帮助等3个主要方面加以改进,具有数据导入、调整设置文件、运行方式以及结果输出4方面的特色.     

具有区间峰值的曲面伸缩因子及其实验

为了改进参数曲面自由变形方法,构造了一种新的伸缩因子函数,它不仅具有以往文献所引入的伸缩因子的特性,还可以在区域上达到峰值,从而克服现有的伸缩因子仅在一点达到峰值的不足。使用新的伸缩因子去作用待变形的曲面方程,从而使曲面发生形变,通过交互改变控制参数来控制曲面的形状,使其能够更好地表示一些实体的外型。实验表明,该方法数学背景简单,易于控制,重复使用可获得丰富的变形效果。适用于几何造型、计算机动画、CAD/CAM等领域。