Stability of international stock market relationships across month of the year and different holding intervals

Potential benefits from international diversification depend upon the stability in stock market relationships. Using monthly data of 11 international stock markets, this paper examines the stability in stock market relationships across month of the year and across different holding intervals. Empirical results show that the correlation structure is more stable than the covariance structure. While empirical evidence supports the hypothesis that the correlation structure is very stable across different holding intervals, the empirical support for the stability in correlation structure across month of the year is much weaker.     

Saltatory Ontogeny and the Life-History Model: Neglected Processes and Patterns of Evolution

A single cell – an egg – cannot be in the same stabilized state as a differentiated multicellular embryo or reproducing adult. The entire ontogeny must, therefore, consist of a sequence of stabilized states. Ontogeny of a phenotype cannot progress gradually but is a saltatory homeorhetic system, proceeding via natural thresholds from one self organized state to the next, hierarchically ever more complex and specialized. The natural boundaries of ontogeny – the far-from-stabilized thresholds – represent also states when changes can be easiest inserted or induced, and especially in the early ontogeny, from the intervals where evolution (change) can occur. As a result, ontogeny can also be divided into distinct life-history intervals called periods, be it embryo, larva (infant, pup), juvenile, adult and senescence, each divided in turn into phases, and each of these into natural steps. It is left to the imagination of scholars in social sciences to find parallels of saltation in economics and history.     

Sequential estimation of a location parameter and powers of a scale parameter from delayed observations

The problem of sequentially estimating a location parameter and powers of a scale parameter is considered in the case when the observations become available at random times. Certain classes of sequential estimation procedures are derived under an invariant balanced loss function and with the observation cost determined by a convex function of the stopping time and the number of observations up to that time.     

并联式混合动力汽车动力合成装置的参数关系

混合动力汽车(HEV)作为燃油机车向电动车过渡的车型目前受到越来越多的关注。在HEV的整个传动路线中,作为动力合成装置的差动轮系和传动系统中的其它环节系统是相对独立的,但它们之间遵循一定的参数匹配关系。本文从转速输出特性和转矩输出特性两方面对参数特性进行了讨论,从而得到差动轮系作为动力合成装置使用时的参数关系,对HEV的参数选取提供了理论依据。     

压路机碾压荷载在施工期对路基拼接变形影响的数值分析

以合肥铁路枢纽改造工程为研究对象,路基拼接中应用的不同压路机碾压荷载为研究目标,通过FLAC软件就不同路基高度下应用不同压路机荷载对既有线列车安全运营和路基稳定性的影响进行了数值模拟计算。结果表明,同一路基高度,不同压路机荷载作用下,坡脚A点和新、老路基搭接处B点的垂直变形增量随压路机荷载的增大而增大;相同压路机荷载下随着路基高度的增加,老路基面、坡脚点以及新老路基搭接处的垂直方向变形与路基高度不成线性关系,采用6 m高度的路基更为合理,有利于线路列车运行的安全性和路基整体的稳定性。     

浅析我国当前通货膨胀的成因及治理对策建议

稳定物价已成为政府宏观调控的重中之重。为避免由于种种原因形成的通货膨胀给我国经济发展带来较大的负面影响,我们必须采取相关措施,要持续的将总量政策和结构政策相很好的组合起来,进行短期应急计划和措施与建立能长期保证制度正常运行并发挥预期功能的制度体系相结合,综合的采取各种各样的政策组合,比较有指向性地使用各种各样的措施在一定程度上减少对造成物价上涨的各种不利因素,抑制通货膨胀蔓延,使我国经济稳定的发展。     

岩土边坡稳定性的遗传算法分析

非线性优化方法主要缺陷在于当边坡土层为非均质复杂条件时,无法保证搜索到安全系数的全局最小解,而只能搜索到局部极小解。基于遗传算法,建立了搜索岩土边坡稳定性分析最小安全系数和滑移面中心坐标与半径的数值方法。问题的可行解在变量搜索区间内搜索,包括滑弧的圆心坐标和半径。数值模拟结果表明,遗传算法搜索到的边坡稳定最小安全系数与理论解是一致的。     

基于Logistic共生模型的汽车园集群研究及稳定性分析

汽车园集群内不同类型企业间的关系类似于种群生态学中不同种群间的相互作用,文章通过逻辑斯蒂(Logistic)模型描述汽车园集群内不同企业间的相互作用。总结了集群内平等型和依托型两种共生模式,求解并分析稳定条件。对汽车园集群这一汽车流通业最新模式的研究具有一定指导意义。     

STABILITY OF THE UTILITY MAXIMIZATION PROBLEM WITH RANDOM ENDOWMENT IN INCOMPLETE MARKETS

We perform a stability analysis for the utility maximization problem in a general semimartingale model where both liquid and illiquid assets (random endowments) are present. Small misspecifications of preferences (as modeled via expected utility), as well as views of the world or the market model (as modeled via subjective probabilities) are considered. Simple sufficient conditions are given for the problem to be well posed, in the sense that the optimal wealth and the marginal utility‐based prices are continuous functionals of preferences and probabilistic views.