时标上二阶线性中立型动力方程有界解的振动准则

考虑时标上的二阶线性中立型动力方程有界解的振动准则,针对p的不同取值分别进行讨论,给出方程有界解振动的条件,分为p〈0,p=0,0〈p〈1,p=1,p〉1五种情况。     

Changing time scale for short-term forecasting in financial markets

A forecasting model based on high-frequency market makers quotes of financial instruments is presented. The statistical behaviour of these time series leads to discussion of the appropriate time scale for forecasting. We introduce variable time scales in a general way and define the new concept of intrinsic time. The latter reflects better the actual trading activity. Changing time scale means forecasting in two steps, first an intrinsic time forecast against physical time, then a price forecast against intrinsic time. The forecasting model consists, for both steps, of a linear combination of non-linear price-based indicators. The indicator weights are continuously re-optimized through a modified linear regression on a moving sample of past prices. The out-of-sample performance of this algorithm is reported on a set of important FX rates and interest rates over many years. It is remarkably consistent. Results for short horizons as well as techniques to measure this performance are discussed.     

时标下的蛛网模型

举出-微分的基本性质,证明一阶-微分方程初值问题解的存在性和惟一性. 提出时标下的蛛网模型, 讨论模型的几种特殊情况.     

近百年来全球及南北半球温度变率

基于对变率的标准差估计,分析了近百年来全球及南北半球月平均温度的一阶变率和二阶变率,讨论了一阶、二阶变率与原序列之间的关系。     

时标上脉冲混合动态系统的稳定性

利用Lyapunov函数方法研究了时标上脉冲混合动态系统关于两个测度的稳定性和渐近稳定性.     

时间尺度上非保守系统的Lie对称性及其守恒量

研究了时间尺度上非保守系统的Lie对称性及其守恒量.首先,基于时间尺度上微分方程在无限小变换下的不变性,导出了时间尺度上Lie对称性的确定方程;然后,建立了时间尺度上非保守系统的Lie对称性的结构方程,以及时间尺度上非保守系统的Lie对称性的Noether型守恒量;最后,举例说明其结果的应用.     

时标上具有依赖状态脉冲动力系统的实用稳定性

考虑时标上具有依赖状态脉冲的动力系统关于两个测度的实用稳定性,将测度函数与Lyapunov函数的特征结合起来,直接利用两个测度函数h0和h本身的特性,得到了两个测度实用稳定的判定结果,而无需另外构造Lya-punov函数.     

Disjunct distribution of Szeptyckiella gen. nov. from New Caledonia and South China undermines the monophyly of Willowsiini (Collembola: Entomobryidae)

Morphology of scales is an important taxonomical character at all levels of Entomobryidae taxonomy. A new scaled genus of Collembola, Szeptyckiella gen. nov., and three new species are described: Szeptyckiella boulouparica sp. nov. and Szeptyckiella sinelloides sp. nov. from New Caledonia, and Szeptyckiella lii sp. nov. from South China. The genus, assigned to Willowsiini, is characterized by pointed scales on the body, eyes and pigment absent, antennal apical bulb absent, dens lacking spines and scales, and bidentate mucro with a short basal spine. It is closest to Hawinella from Hawaii but the latter possesses a falcate mucro. However, its morphological characteristics and its disjunct distribution raise a number of problems. Its widely disjunct distribution is difficult to explain in terms of palaeobiogeographical or more recent dispersal events. The new genus is similar to Sinella without consideration of scales, although both genera are placed in different tribes following the current supra-generic classification of Entomobryidae. We discuss other cases of paired genera differing only by the presence or absence of scales, and placed in either Willowsiini or Entomobryini. On this basis, we assume that scale presence could independently occur in the former tribe, questioning the monophyly of the tribe Willowsiini.     

基于改进鲸鱼优化算法的微网系统能量优化管理

针对包含多种可再生能源的冷热电联供型微网系统的能量优化问题,为了优化其运行过程的经济效益和环境效益,本文提出一种基于改进鲸鱼优化算法的多时间尺度下能量优化方法,首先根据长短期记忆网络(Long Short Term Memory,LSTM)预测得到的可再生能源出力和负荷需求预先制定调度规划,然后以此预测数据为基础,采用改进鲸鱼优化算法调整可控设备出力,优化微网系统的运行成本和固定成本。将该方法应用于某楼宇冷热电联供型微网,结果表明,在满足负荷需求的基础上使得经济成本平均降低4.03%且经济效益更优。     

函数在一类时标意义下的积分

时标意义下的积分是时标动力学中的难点之一，函数在一般时标意义下很难求出其积分，本文在求特殊时标的函数积分方法的基础上拓展出求函数在一类时标上积分的方法．