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排序方式： 共有218条查询结果，搜索用时 35 毫秒
1.
This study analyzes sovereign risk contagion between four East Asian economies (China, Hong Kong, Japan, and Korea) and its structural changes through the Global Financial Crisis (GFC) and the European Debt Crisis (EDC) by applying the mixture of time-varying copulas to those economies’ credit default swap (CDS) spreads.
This article first finds a strong contagion from the US and PIIGS economies to the East Asian sovereign CDS markets and intraregional contagion within the East Asian markets. Second, the impact of contagion is different according to whether it is measured by the linear (Gaussian) or the upper tail dependence. Third, Japan plays an important role in increasing the linear dependence whereas China and Korea are crucial in terms of the upper tail dependence. Lastly, the GFC has structurally increased the linear dependence but not the upper tail dependence between the East Asian sovereign CDS markets. 相似文献
2.
本文结合废旧沥青混合料再生技术的理论基础,通过旧料抽提试验确定废旧料的配合比,采用再生剂对废旧料进行性能改善.然后,加入新沥青及新集料,拌制新沥青混合料,检测其性能.通过试验,确定新旧料掺配率、再生剂对废旧沥青混合料性能的影响,为沥青混合料再生工艺提供参考借鉴. 相似文献
3.
为了提升硬盘读取数据的效果,进一步增加硬盘的存储量,对头盘界面空间散热的影响因素及其影响规律,以及氦-空混合气体环境下润滑剂的迁移规律进行研究,建立了磁头磁盘界面空间气浮轴承模型和热辅助下磁头磁盘界面空间润滑剂迁移的分子动力学模型,并以此为基础将气浮轴承模拟结果输入到模型中,探析氦气质量分数及其他影响参数对头盘界面空间散热的影响规律,以及激光热流及其他影响参数对氦-空混合气体环境下润滑剂迁移的规律。结果表明：氦气质量分数加剧了头盘界面空间的散热强度;与磁头飞行高度相比,润滑剂厚度、环境压强的增大更利于磁头磁盘界面空间的散热;润滑剂转移量随激光热流、磁盘速度的增大而增大;随着脉冲光斑尺寸的增加,润滑剂转移量先增加后减小,且光斑半径为20σ时润滑剂转移量达到最大值;Zdol2000,Zdol4000,Ztetraol2000及ZTMD等4种润滑剂中,Zdol4000造成的润滑剂转移量最大。研究获得的头盘界面空间散热因素及热辅助下影响润滑剂转移量影响因素的结果,能够为充氦热辅助硬盘的设计提供理论依据,也可为下一代磁存储记录技术的发展提供技术支持。 相似文献
4.
在进行沥青混合料配合比设计时,由于掺加两种或两种以上掺合物时,采用马歇尔试验法或正交试验法进行沥青混合料配合比存在不足,为了确定沥青混合料最佳配合比,通过基于响应曲面法中的BBD(Box-Behnken design)法对级配类型AC-13掺加玄武岩纤维、RAP的热再生沥青混合料进行级配优化设计.结果表明,计算优化得出最佳油石比为5.17％、旧料掺量RAP为31.89％及玄武岩纤维掺量0.26％.并通过试验对预测模型进行验证,预测值与实测值模型之间相对误差较小(小于3％),可见BBD法建立的二阶模型具有较好的拟合效果,对再生沥青混合料各掺量配合比设计能进行有效优化,并且最佳各掺量下的玄武岩纤维热再生沥青混合料具有良好的路用性能. 相似文献
5.
In this paper, we propose a co-integration model with a logistic mixture auto-regressive equilibrium error (co-integrated LMAR), in which the equilibrium relationship among cumulative returns of different financial assets is modelled by a logistic mixture autoregressive time series model. The traditional autoregression (AR) based unit root test (ADF test), used in testing co-integration, cannot give a sound explanation when a time series passes the ADF test. However, its largest root in the AR polynomial is extremely close to, but less than, one, which is most likely the result of a mixture of random-walk and mean-reverting processes in the time series data. With this background, we put an LMAR model into the co-integration framework to identify baskets that have a large spread but are still well co-integrated. A sufficient condition for the stationarity of the LMAR model is given and proved using a Markovian approach. A two-step estimating procedure, combining least-squares estimation and the Expectation-Maximization (EM) algorithm, is given. The Bayesian information criterion (BIC) is used in model selection. The co-integrated LMAR model is applied to basket trading, which is a widely used tool for arbitrage. We use simulation to assess the model in basket trading strategies with the statistical arbitrage feature in equity markets. Data from several sectors of the Hong Kong Hang Seng Index are used in a simulation study on basket trading. Empirical results show that a portfolio using the co-integrated LMAR model has a higher return than portfolios selected by traditional methods. Although the volatility in the return increases, the Sharpe ratio also increases in most cases. This risk–return profile can be explained by the shorter converging period in the co-integrated LMAR model and the larger volatility in the ‘mean-reverting’ regime. 相似文献
6.
We consider kernel density estimation for univariate distributions. The question of interest is as follows: given that the data analyst has some background knowledge on the modality of the data (for instance, ‘data of this type are usually bimodal’), what is the adequate bandwidth to choose? We answer this question by extending Silverman's idea of ‘normal‐reference’ to that of ‘reference to a Gaussian mixture’. The concept is illustrated in the light of real data examples. 相似文献
7.
M. C. Jones; 《Statistica Neerlandica》2024,78(3):563-568
In a recent article, J. Peyhardi gives a number of novel results related to quasi Pólya thinning which encompass a number of important mixture relationships between univariate discrete distributions. In this note, I explore the duals of the general results on convolution thinning given in Peyhardi's Theorem 1 in order to obtain new relationships and to gain new insights into old relationships. Some consequences—for integer-valued autoregressive processes—and analogues—in the continuous case—are noted. 相似文献
8.
9.
随着桥梁工程建设越来越注重砼外观质量,特别是城市及旅游景点的桥梁工程,出露的结构物往往要求一次浇筑成型,面层平整光滑、色泽均匀,棱角顺直、无碰损和污染,不需做任何外装饰,直接采用现浇砼的自然色作为饰面。文章通过模板、砼配合比、砼浇筑及振捣等方面详细阐述了确保砼外观质量的技术措施。 相似文献
10.
This paper deals with the estimation of the scale matrix of a multivariatet-model with unknown location vector and scale matrix to improve upon the usual estimators based on the sample sum of product
matrix. The well-known results of the estimation of the scale matrix of the multivariate normal model under the assumption
of entropy loss function have been generalized to that of a multivariatet-model.
The paper is based on the first author’s unpublished Ph.D. dissertation ‘Estimation of the Scale Matrix of a Multivariate
T-model’, University of Western Ontario, Canada. Present address: School of Mathematics and Statistics, The University of
Sydney, NSW 2006, Australia. 相似文献