跳高运动的历史沿革和发展趋势研究

阐述了跳高运动的起源、早期和后期的发展以及目前我国跳高运动的发展状况,并对未来跳高运动的发展趋势作了研究.同时对目前我国的跳高运动存在的问题作了深入地分析与探讨,指出我国的跳高训练没能顺应国际发展的潮流,没有高质量的运动梯队,国家应出台倾斜政策,改革运动员选材培养管理体制.     

The Volatility and Density Prediction Performance of Alternative GARCH Models

This study compares the volatility and density prediction performance of alternative GARCH models with different conditional distribution specifications. The conditional residuals are specified as normal, skewedHyphen;t or compound Poisson (jump) distribution based upon a nonlinear and asymmetric GARCH (NGARCH) model framework. The empirical results for the S&P 500 and FTSE 100 index returns suggest that the jump model outperforms all other models in terms of both volatility forecasting and density prediction. Nevertheless, the superiority of the nonHyphen;normal models is not always significant and diminished during the sample period on those occasions when volatility experiences an obvious structural change. Copyright © 2011 John Wiley & Sons, Ltd.     

翼面几何不规则性对压力分布影响的数值模拟研究

通过求解二维雷诺平均Navier-Stokes方程(RANS)及SST k-ω二方程湍流模型,数值模拟表面存在几何不规则的突起物或凹坑的翼型绕流。分析对比了不同位置处多种类型的突起物和凹坑在不同的高度下对翼型压力分布、激波位置的影响。对翼型测压实验中所出现的压力跳动给出了一种解释,有助于指导风洞实验,提高实验精度,并对实验数据进行合理的修正。     

一类进入与退出投资决策的评价

在利用项目产品的价格服从几何布朗运动-跳跃过程来评价进入与退出投资策略时,项目产品的价格可能受到正向或者负向的跳跃所带来的冲击．基于这种认识,通过实物期权方法来评估项目的价值,运用动态规划方法推出投资机会的价值,通过数值分析模型,讨论了参数对投资的影响。     

我国跳高运动基本现状及发展对策研究

运用文献资料调研、教学试验、专家访谈等方法对我国跳高项目基本实力现状进行剖析,结果表明,我国跳高整体状况不尽人意,水平亟待提高,但也具备项目发展的可行性及有利条件,在此基础上提出了我国跳高运动发展的总体策略．     

一类不确定Markov跳跃系统的鲁棒跟踪与模型跟随

讨论了一类不确定Markov跳跃线性系统的鲁棒跟踪与模型跟随问题。通过构造一组非线性鲁棒状态反馈跟踪控制器来跟踪给定的动态信号,该控制器确保系统当T→∞时是以扰动衰减系数γ鲁棒随机稳定的,且跟踪误差有界。最后给出算例说明了所设计的鲁棒跟踪控制器的性能。     

Forecasting realized volatility of oil futures market: A new insight

In this study we propose several new variables, such as continuous realized semi‐variance and signed jump variations including jump tests, and construct a new heterogeneous autoregressive model for realized volatility models to investigate the impacts that those new variables have on forecasting oil price volatility. In‐sample results indicate that past negative returns have greater effects on future volatility than that of positive returns, and our new signed jump variations have a significantly negative influence on the future volatility. Out‐of‐sample empirical results with several robust checks demonstrate that our proposed models can not only obtain better performance in forecasting volatility but also garner larger economic values than can the existing models discussed in this paper.     

Variation of the NAO and NPO associated with climate jump in the 1960s

The interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO) and its relationship with the climate jump in the Northern Hemisphere in the 1960s, are discussed using the data analyses. It is clearly shown that the amplitudes of the NAO and NPO were all increased obviously in the 1960s and the main period of the oscillations changed from 3–4 years before the 1960s to 8–15 years after the 1960s. Therefore, the climate jump in the 1960s is closely related to the anomalies of the NAO and NPO.     

青少年跳远运动员的早期选材

跳远是一项对运动员的力量、速度、弹跳等综合素质要求很高的田径运动项目。科学的选材是培养一名优秀跳远运动员的前提和基础。本文仅就青少年跳远运动员早期选材相关问题展开粗浅的探讨 ,以期对学校的体育教学和训练提供理论依据     

用3.1eV光辐射测量法研制光纤Bragg光栅

给出了用 3.1 e V(波长 40 0 nm)荧光监测法在载氢商用通信光纤上制作光纤 Bragg光栅的实验。采用 2 4 4 nm SHG(二次谐波振荡 ) :氩离子激光器和振动掩模 ,在其 Bragg中心波长 (λ=1 5 5 0 .65 nm) ,得到反射率 96%和 3d B带宽 0 .2 nm的光纤光栅。这种光纤光栅在光纤传感系统具有广泛的应用价值。