基于周期变量的经济预测分析

由于商业和经济时间序列运行中存在周期性经济扩张与经济紧缩交替更迭、循环往复现象,为避免经济出现较大波动,本文以此建立相应模型,对经济运行进行科学预测,并提出了具体的预测方法。

复杂系统周期性变量的时差分类（非线性复杂系统的综合技术Ⅶ）

复杂系统周期性变量的时差分类（非线性复杂系统的综合技术Ⅶ）项静恬，吴国富（中科院应用数学研究所北京１０００８０）ξ２．３周期性变量的时差分类不少复杂系统的输入输出具有周期起伏的规律，因而须将相互同步的变量归为一类、本节以宏观经济指标体系为背景．讨论周...

具有变量时滞的周期微分系统的周期解

本文考虑周期微分系统x(t) =A(t,x(t- r1(t) ) ) x(t) + f (t,x (t- r2 (t) ) )的 T-周期解的存在性问题 ,其中 (t,x)∈R× Rn,A(t,x)是 n× n连续矩阵函数 ,f(t,x)是 n维连续向量函数 ,时滞 ri(t) (i=1,2 )是连续函数 ,且 A(t+ T,x) =A(t,x) ,f(t+ T,x) =f(t,x) ,ri(t+ T) =ri(t) (i=1,2 ) ,常数T>0 .本文利用不动点方法 ,建立了保证系统存在 T-周期解的充分条件 ,推广了文 [1- 3]的相关结果 .

带有周期性名义变量的混合型数据聚类分析

针对混合型数据中周期性名义变量的观测之间的距离刻画样品间相似性的不足,提出了一种对周期性名义变量的观测进行量化处理的新方法,并以此为依据定义新的距离来刻画样品间的相似性。在实际数据集上进行实验,实验结果表明:所提出的量化方法及新的距离公式在刻画观测之间的相似度时更合理,能提高混合型数据聚类的精度。

金融周期对宏观经济稳定的影响异质性分析

宏观经济稳定长期以来作为中国宏观调控的重要目标,在“新常态”时期被更加广泛关注。金融稳定作为宏观经济稳定的必要条件,以洞悉金融周期为前提,要求细究金融周期变量对宏观经济运行的影响,为政策精准性提供支持。本文利用相关金融周期和宏观经济变量季度数据,使用滤波方法找出宏观经济的波动和平稳时期,运用机器学习算法验证所选输入变量与输出变量的匹配度,并测度各输入变量对输出变量的重要度。本文发现波动期和平稳时期宏观经济表现虽有不同,但资产价格指数和信贷水平对各宏观经济变量的重要度之和都达到50%以上,而其他金融周期变量如利差、杠杆率和金融机构风险暴露的重要度则有限。这表明相关政策需有的放矢,相较于无差别的大规模释放流动性,可将重心置于维护资产价格稳定和优化信贷政策配给,为宏观经济稳定保驾护航。

社会变迁与变量兴衰

本文分别以体态、受教育程度、私人汽车、手机、住房、收入、财富与社会分层的关系阐述变量区分度随社会变迁而变化,一般表现为转向、衰老、诞生和模糊四种形态。变量兴衰主要有如下两大影响:一是变量区隔度减弱导致研究结果的可靠性下降;二是变量区隔度增强能更好地解释所要研究的现象。变量区隔度变化可以概括成变量生命周期,即变量随时间变化的运动过程,划分成开发、成长、成熟与老化四个阶段。

由CDSN数据测定IPz分量谱震级初探

本文尝试用ＣＤｓＮ的ＩＰｚ分量强震记录来测定谱震级。通过对测出的谱震级ｍ＿（Ｔ）与体波震级ｍ＿（Ｂ）、ｍ＿（ｂ）的相关分析，得出其反映震源特性的峰值，出现在周期Ｔ＝１秒左右。此外，谱震级还有随周期而变化的特性。根据谱震级与能量的关系，推导了它的通用形式为ａｍ＿（Ｔ）＝ｌｏｇ（Ｅ／Ｅ０）（式中ａ＝２，ｌｏｇＥ＿０＝５．６）。它的最高震级为９．６级。运用谱震级的通用形式对本文测定的４个谱震级进行检验，结果表明它比传统方法测定的ＩＰｚ分量体波震级ｍ＿（Ｂ）系统偏小０．３１级。因谱震级是扣除了介质滞弹性吸收影响后的产物，故这种偏差是比较合理的。

电机起动过程信号的分析

简单地介绍了设备过程信号分析的传统分析方法 ,结合电机起动过程信号的取样数据 ,提出了频谱分段法和周期变量法。通过这两种方法的分析获得了众多时、频域参量的特性曲线和特征值 ,这些特征量的获得是传统分析方法不易得到的。这两种方法可应用于设备的类型识别和故障诊断等领域。

变形Boussinesq方程组的精确解

利用简化齐次平衡方法,导出了从一个线性方程的解到变形Boussinesq方程组的解之间的非线性变换。借助于线性方程的解及非线性变换,求出了变形Boussinesq方程组的多重孤波解、有理函数解及关于空间变量的周期解等。

人体细胞学

9931172 细胞的力觉:要注意机械刺激[日]/曾我部正博∥治疗学.-1998,32(6).-34～36 冀医情 9931173 固定延迟对有丝分裂活动及流式细胞仪检测细胞周期变量的影响/Berg-ers E∥Hum Pathol.-1997,28(1).-95～100

Applications of F-expansion to Periodic Wave Solutions for Variant Boussinesq Equations

We present an F-expansion method for finding periodic wave solutions of nonlinear evolution equations in mathematical physics, which can be thought of as a concentration of extended Jacobi elliptic function expansion method proposed recently. By using the F-expansion, without calculating Jacobi elliptic functions, we obtain simultaneously many periodic wave solutions expressed by various Jacobi elliptic functions for the variant Boussinesq equations. When the modulus m approaches 1 and O, the hyperbolic function solutions （including the solitary wave solutions） and trigonometric solutions are also given respectively.

Multi-Time Scale Analysis of Runoff at the Yangtze Estuary Based on the Morlet Wavelet Transform Method

Runoff series of the Yangtze River presents an intricate variation tendency under the reinforced influence of human activities.The Morlet Wavelet Transform method has been applied to analyze the annual runoff data from 1950 to 2011 at the Yangtze River Estuary.It can clearly reveal the multi-time scales structure,break point,change and distribution of periodic variation in the different time scales of the runoff series.The main conclusions are that:1) Repeated periodic oscillations accompanied by an extremely large fluctuation are presented in the runoff series with an obvious difference between wet and dry years,and the major periods of the time series are about 3,8,16 and 23 years respectively.Among them,the presented maximum periodic oscillation is 23 years scale.2) In the 23-year time scale,the wet periods are 1950-1958,1969-1980 and 1992-2003,and the dry periods are 1959-1968,1981-1991 and 2004-2011.3) It can be predicted from the view of long time scales that the low annual runoff will likely occur in the near future.

Undrained response of reconstituted clay to cyclic pure principal stress rotation

A series of monotonic and rotational shearing tests are carried out on reconstituted clay using a hollow cylinder apparatus under undrained condition. In the rotational shearing tests, the principal stress axes rotate cyclically with the magnitudes of the principal stresses keeping constant. The anisotropy of the reconstituted clay is analyzed from the monotonic shearing tests. Obvious pore pressure is induced by the principal stress rotation alone even with shear stress q0=5 k Pa. Strain components also accumulate with increasing the number of cycles and increases suddenly at the onset of failure. The deviatoric shear strain of 7.5% can be taken as the failure criterion for clay subjected to the pure cyclic principal stress rotation. The intermediate principal stress parameter b plays a significant role in the development of pore pressure and strain. Specimens are weakened by cyclic rotational shearing as the shear modulus decreases with increasing the number of cycles, and the shear modulus reduces more quickly with larger b. Clear deviation between the directions of the principal plastic strain increment and the principal stress is observed during pure principal stress rotation. Both the coaxial and non-coaxial plastic mechanisms should be taken into consideration to simulate the deformation behavior of clay under pure principal stress rotation. The mechanism of the soil response to the pure principal stress rotation is discussed based on the experimental observations.

Reproductive Cycle and Seasonal Variations in Lipid Content and Fatty Acid Composition in Gonad of the Cockle Fulvia mutica in Relation to Temperature and Food

From March 2004 to February 2005,seasonal variations in lipid content and fatty acid composition of gonad of the cockle Fulvia mutica(Reeve) were studied on the eastern coast of China in relation to the reproductive cycle and environment conditions(e.g.,temperature and food availability).Histological analysis as well as lipid and fatty acid analyses were performed on neutral and polar lipids of the gonad.Results showed that gametogenesis occurred in winter and spring at the expense of lipids previously accumulated in summer and autumn,whereas spawning occurred in summer(20.4-24.6℃).The seasonal variation in lipid content was similar to that of the mean oocyte diameter.In both neutral and polar lipids,the 20:5n-3 and 22:6n-3 levels were relatively higher than saturated fatty acids,and polyunsaturated fatty acids were abundant,with series n-3 as the predominant component.Seasonal variations in the 20:5n-3 and 22:6n-3 levels and the principal n-3 fatty acids were clearly related to the reproductive cycle.The ∑(n-3) and ∑(n-6) values were relatively high during January-May,and the associated unsaturation index was significantly higher than that in other months.The results suggest that fatty acids play an important role in the gametogenesis of F.mutica.

Quasi-periodic and Non-periodic Waves in （2q-1）-Dimensional Nonlinear Systems

New exact quasi-periodic and non-periodic solutions for the （2＋ 1）-dimensional nonlinear systems are studied by means of the multi-linear variable separation approach （MLVSA） and the Jacobi elliptic functions with the space-time-dependent modulus. Though the result is valid for all the MLVSA solvable models, it is explicitly shown for the long-wave and short-wave interaction model.

Doubly Periodic Propagating Wave Patterns of （2＋1）-Dimensional Maccari System

Using the variable separation approach, we obtain a general exact solution with arbitrary variable separation functions for the （2＋ 1）-dimensional Maccari system. By introducing Jacobi elliptic functions dn and nd in the seed solution, two types of doubly periodic propagating wave patterns are derived. We invest/gate the wave patterns evolution along with the modulus k increasing, many important and interesting properties are revealed.

A Note on "Doubly Periodic Propagating Wave for (2+1)-Dimensional Breaking Soliton Equation"

In a recent paper [Commun. Theor. Phys. （Beijing, China） 49 （2008） 268], Huang et al. gave a general variable separation solution to the （2＋1）-dimensional breaking soliton equation via a special Biicldund transformation and the variable separation approach. In terms of the derived variable separation solution and by introducing Jacobi elliptic functions, they claimed that nonelastic types of interaction between Jacobi elliptic function waves are investigated both analytically and graphically. We show that some inappropriateness or errors exist in their paper, and say nothing of the conclusion that some nonelastic types of interaction between Jacobi elliptic function waves in the （2＋1）-dimensional breaking soliton equation have been found.

Measurement of the Variation of Shear Velocity on Bed during a Wave Cycle

Almost all works in the field of boundary layer flow under the breaking wave consider the flow similar as the flow in an oscillating pressure tube. Although the two flows are similar, there are many differences. The results achieved in such manner are therefore also only similar to the results that can be achieved during measurements in the surf zone. Present article deals with boundary layer measurements on an inclined bottom under breaking waves. The measurements over the whole wave cycle were carried out, and the shear velocity under the breaking wave was calculated based on the measurements. It was found that there is a considerable space and time variation of the term in the surf zone. The turbulence generated during the wave breaking changes the shape of the shear velocity profile in comparison to the profile measured before breaking. As the values of shear velocity are directly correlated with the description of the whole velocity field in the wave, it can be assumed that the enhanced description of the shear velocity results in better understanding of the whole velocity field under breaking waves. Therefore, the article brings a new insight into the field and aims to make a discussion about the need to rethink the way of describing the boundary layer flow in the surf zone.

金融周期对宏观经济稳定的影响、微观传导机制和政策挑战

随着金融周期在次贷危机中的重要作用和与经济周期出现分化的特征日益显现,基于安全稳健的监管实践已难以熨平金融周期和维护宏观经济稳定,次贷危机所引起的持续衰退对货币经济学的研究范式产生了影响深远。这就要求学术界和监管当局更加关注金融周期对宏观经济稳定的影响和识别其微观传导机制,为政策措施执行的目标精准性提供支持。本文由金融周期变量研究的新进展入手,从金融周期变量对宏观经济稳定的影响、微观传导机制与政策挑战和实践三个方面对相关文献进行综述。根据现有研究,金融周期变量对宏观经济稳定的影响关注债务冲击、信贷冲击、资产价格冲击和不确定性冲击;金融周期变量对宏观经济稳定的微观传导机制则主要剖析与企业、家庭和金融机构相关的渠道;政策挑战和实践则介绍了宏观审慎、财政政策和货币政策的实践在熨平金融周期时存在的问题;最后指出未来的研究方向。

基于轨道交通信号配时自动控制设计路径研究

在轨道交通自动控制系统领域,尤其是信号配时的多目标优化方面,现有技术在动态复杂环境的适应性方面存在不足。研究提出多目标配时优化算法,并且对信号配时的三种指标进行权重赋值,最后通过周期时长与绿信比对算法粒子位置进行更新。研究结果显示,该算法经过100次迭代训练后,在通行能力、平均延误时间和平均停车次数上均有显著改善。在高峰期,优化后算法的平均延误时长为31.27 s,平均停车次数为0.77次,分别下降了1.29 s和0.05次;在平峰期,优化后算法的平均延误时间为17.59 s,平均停车次数为0.61次,分别下降0.75 s和0.02次。结果表明,研究提出的方法能在轨道交通效率和安全性方面具有较好的提升效果。