一种改进的Canny自适应边缘检测算法

针对原始的Canny边缘检测算法高低阈值不利于选择的问题,提出一种改进的Canny自适应边缘检测算法。该方法采用3×3的Sobel边缘算子模板代替2×2邻域内求有限差分来计算梯度幅值;利用梯度直方图来选取高低阈值,提高了算法的自适应性;在边缘的连接上采用边界追踪的方法,来保证边缘的连续性和唯一性。以20m m量块图像边缘检测为例进行了实验。结果表明,该算法在保证实时性的同时,具有更好的检测精度和准确度,细化图像边缘和抑制伪边缘噪声方面的性能也得到了提高,是一种有益的边缘检测改善方法。     

基于梯形算子的AFM驱动器非对称迟滞性校正

原子力显微镜(AFM)通常采用压电陶瓷(PZT)作为驱动器以实现纳米尺度的观测和操作。然而,PZT自身的迟滞非线性会对AFM观测质量和操作精度产生很大影响。基于Prandtl-Ishlinskii(PI)模型的前馈控制方法可对PZT的迟滞非线性进行补偿,但传统PI模型无法消除PZT的非对称迟滞性的影响。针对这个问题,提出一种基于梯形算子的非对称迟滞模型,并可用系统辨识方法获取逆模型参数,该方法可有效实现具有非对称迟滞特性驱动器的前馈补偿控制。AFM系统实验证明,该模型可有效减小非对称迟滞性导致的建模误差,基于该模型的前馈迟滞补偿控制可有效提高AFM的扫描成像质量。     

基于Hamacher区间模糊算法的技术状态评估权重确定

针对复杂装备技术状态评估权重确定过程中存在的专家犹豫和权重确定动态性不足的问题,结合区间值犹豫模糊熵、毕达哥拉斯模糊集和Hamacher算子,提出Hamacher区间模糊算法。综合各专家对各元素重要性的打分,构建区间值犹豫模糊集,改进区间值犹豫模糊熵,并对模糊集中各犹豫模糊元运算得到区间值犹豫模糊熵矩阵;令区间值犹豫模糊熵为隶属度,打分区间差值为犹豫度,得到毕达哥拉斯模糊集,运用Hamacher区间模糊算法计算得到各元素重要度得分函数,将得分函数归一化得到最终元素权重。算例结果表明,该验证方法对技术状态评估具有适用性。     

Next-generation tools for evolutionary invasion analyses

Evolutionary invasion analysis is a powerful technique for modelling in evolutionary biology. The general approach is to derive an expression for the growth rate of a mutant allele encoding some novel phenotype, and then to use this expression to predict long-term evolutionary outcomes. Mathematically, such ‘invasion fitness’ expressions are most often derived using standard linear stability analyses from dynamical systems theory. Interestingly, there is a mathematically equivalent approach to such stability analyses that is often employed in mathematical epidemiology, and that is based on so-called ‘next-generation’ matrices. Although this next-generation matrix approach has sometimes also been used in evolutionary invasion analyses, it is not yet common in this area despite the fact that it can sometimes greatly simplify calculations. The aim of this article is to bring the approach to a wider evolutionary audience in two ways. First, we review the next-generation matrix approach and provide a novel, and easily intuited, interpretation of how this approach relates to more standard techniques. Second, we illustrate next-generation methods in evolutionary invasion analysis through a series of informative examples. Although focusing primarily on evolutionary invasion analysis, we provide several insights that apply to biological modelling in general.     

Algorithm design and implementation of finite wavelet grow tree

Based on grow tree composite model, Finite Field Wavelet Grow Tree (FW-GT) was proposed in this paper. FW-GT is a novel framework to be used in data encryption enhancing data security. It is implemented by replacement operator and wavelet operator. Forward integration and inverse decomposition of FW-GT are performed by replacement, inverse wavelets and its corresponding replacement, wavelet transforms. Replacement operator joined nonlinear factor, wavelet operator completed data transformation between lower dimensional space and higher dimensional space. FW-GT security relies on the difficulty of solving nonlinear equations over finite fields. By using FW-GT, high security of data could be obtained at the cost of low computational complexity. It proved FW-GT algorithm’s correctness in this paper. The experimental result and theory analysis shows the excellent performance of the algorithm.     

Financing investment in the European electricity transmission network: Consequences on long-term sustainability of the TSOs financial structure

This article focuses on the ability of European TSOs to meet the demand for substantial investments in the electricity transmission grid over the next two decades. We employ quantitative analysis to assess the impact of the required capital expenditures under a set of alternative financing strategies. We consider a best-case scenario of full cooperation between the European TSOs. It appears that under current trends in the evolution of transmission tariffs, only half the volumes of investment currently planned could be funded. A highly significant increase in transmission tariffs will be required to ensure the whole-scale investments can be delivered. Finally, alternative strategies can dampen the impact on tariffs but they can only partially substitute for this increase in charges paid by network users.     

Energy management in metro-transit systems: An innovative proposal toward an integrated and sustainable urban mobility system including plug-in electric vehicles

The energy consumptions growth, the upward interest for environmental sustainability and the technological evolution carry to the necessity to review the planning criteria of urban mobility systems in large cities and metropolitan areas. With this aim, new studies and projects are in progress, especially dealing with the power systems for metro-transit lines and surface electric vehicles. In this framework, the authors perform a study that, from an overview about the main energy management issues connected to the city transport, provides an innovative proposal for the design of sustainable urban mobility system: the integration of the metro-lines with surface plug-in electric vehicles. The present paper includes the energy analysis results, obtained by an application on a real case study of an home-made simulation software, describes the proposal in terms of power systems architecture and business models, pointing out the potential advantages that its implementation could give in terms of energy saving, environmental sustainability and reduced economic impact, as a result of the maximum exploitation of existing electric power plant.     

A model of driver behaviour

The driver-vehicle-environment system is characterized by the driver's ability to receive information from the environment and to react upon it by activating the controls of the vehicle. Modelling this system one has to take into account that it is complex. After introducing the model the required operations for the driver's eye and hand movements are demonstrated by means of selected examples drawn from driving-simulator runs. First analyses indicate the principal applicabilities of the fuzzy driver model for further research.