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11.
考虑线性变换对约束线性模型回归系数的影响问题,证明了观测数据的线性变换对于约束模型的影响可以通过一个可用两步约束最小二乘法解决的约束回归问题进行了分析,得到了回归系数的约束可估函数的约束最佳线尾无偏估计不受变换影响的充要条件。 相似文献
12.
通过产业结构偏离度的分解和比较,对云南第三产业就业进行实证分析,较充分论证了云南第三产业还有很大的吸纳就业的潜力,并指出了就业有效增长的第三产业内部行业的选择.研究表明:(1)近10年,云南一、二、三产业的就业贡献率分别为27.8%、2.2%、69.9%,新增就业岗位的69.9%由第三产业提供,第三产业产值每增长1个百分点,平均增加就业岗位就达1.56万个,比第二产业多0.9万个;(2)云南第三产业在发展的同时没有充分发挥其吸纳就业的能力,还有很大的就业吸纳空间;(3)批发零售贸易餐饮业、社区服务业将是云南第三产业扩大就业的主要行业,而交通运输仓储及邮电通信业则很难有较大吸纳就业的空间. 相似文献
13.
ITS研究中,动态OD矩阵估计是交通动态分配的关键因素。针对OD矩阵难以获得的问题,回顾动态OD矩阵估计理论的发展历程,明确该领域研究中的三个关键问题:状态变量的选择、系统方程的确定、OD量与路段流量的关系(分配矩阵)。在此基础上介绍一种基于历史OD矩阵数据的估计方法,卡尔曼滤波算法,为动态OD矩阵估计理论的进一步的研究奠定基础。 相似文献
14.
Sequential estimation problems for the mean parameter of an exponential distribution has received much attention over the
years. Purely sequential and accelerated sequential estimators and their asymptotic second-order characteristics have been
laid out in the existing literature, both for minimum risk point as well as bounded length confidence interval estimation
of the mean parameter. Having obtained a data set from such sequentially designed experiments, the paper investigates estimation
problems for the associatedreliability function. Second-order approximations are provided for the bias and mean squared error of the proposed estimator of the reliability
function, first under a general setup. An ad hoc bias-corrected version is also introduced. Then, the proposed estimator is
investigated further under some specific sequential sampling strategies, already available in the literature. In the end,
simulation results are presented for comparing the proposed estimators of the reliability function for moderate sample sizes
and various sequential sampling strategies. 相似文献
15.
For a balanced two-way mixed model, the maximum likelihood (ML) and restricted ML (REML) estimators of the variance components were obtained and compared under the non-negativity requirements of the variance components by L ee and K apadia (1984). In this note, for a mixed (random blocks) incomplete block model, explicit forms for the REML estimators of variance components are obtained. They are always non-negative and have smaller mean squared error (MSE) than the analysis of variance (AOV) estimators. The asymptotic sampling variances of the maximum likelihood (ML) estimators and the REML estimators are compared and the balanced incomplete block design (BIBD) is considered as a special case. The ML estimators are shown to have smaller asymptotic variances than the REML estimators, but a numerical result in the randomized complete block design (RCBD) demonstrated that the performances of the REML and ML estimators are not much different in the MSE sense. 相似文献
16.
外生冲击与房地产真实价格波动--对1998~2003年中国31省(市、区)的实证研究 总被引:1,自引:0,他引:1
文章首先根据经济学模型界定了两个重要指标:自相关系数与收敛系数.认为不同的外生冲击对这两个系数有不同的影响,而它们决定了房地产真实价格波动形态的差异.在此基础上,文章利用1998~2003年中国31个省(市、区)的面板数据对中国房地产市场进行了实证研究,其结论是,在真实人均可支配收入和真实建筑成本较高、真实税后住宅抵押贷款利率较低的地区有较大的自相关系数和较小的收敛系数,从而房地产真实价格具有更大的波动性.为使房地产真实价格在均衡价格附近平稳运行,降低开发成本和提高消费者购买成本能收到较好的效果. 相似文献
17.
We compare a number of models of post War US output growth in terms of the degree and pattern of non-linearity they impart
to the conditional mean, where we condition on either the previous period's growth rate, or the previous two periods' growth
rates. The conditional means are estimated non-parametrically using a nearest-neighbour technique on data simulated from the
models. In this way, we condense the complex, dynamic, responses that may be present in to graphical displays of the implied
conditional mean.
First version received: Feb. 1999/Final version received: June 2001 相似文献
18.
This paper proposes an approach to the intraday analysis of diversified world stock accumulation indices. The growth optimal portfolio (GOP) is used as reference unit or benchmark in a continuous financial market model. Diversified portfolios, covering the world stock market, are constructed and shown to approximate the GOP, providing the basis for a range of financial applications. The normalized GOP is modeled as a time transformed square root process of dimension four. Its dynamics are empirically verified for several world stock indices. Furthermore, the evolution of the transformed time is modeled as the integral over a rapidly evolving mean-reverting market activity process with deterministic volatility. The empirical findings suggest a rather simple and robust model for a world stock index that reflects the historical evolution, by using only a few readily observable parameters.
Mathematics Subject Classification: (1991) primary 90A12, secondary 60G30,62P20
JEL Classification: G10, G13 相似文献
19.
Portfolio Optimization under Lower Partial Risk Measures 总被引:2,自引:0,他引:2
Portfolio management using lower partial risk (downside risk) measures is attracting more attention of practitioners in recent years. The purpose of this paper is to review important characteristics of these riskmeasures and conduct simulation using four alternative measures, lower semi-variance, lower semi-absolute deviation, first order below targetrisk and conditional value-at-risk.We will show that these risk measures are useful to control downside risk whenthe distribution of assets is non-symmetric. Further, we will propose a computational scheme to resolve the difficultyassociated with solving a large dense linear programming problems resulting from these models. We will demonstrate that this method can in fact solve problems consisting of104 assets and 105 scenarios within a practical amount of CPU time. 相似文献
20.
《Socio》2021
The present inquiry lays a groundwork for the analysis of the net greenhouse gas (GHG) footprint of oil in the oil-abundant settings. To address the research question, the study puts forward a three-sector decision model, which provides a common ground for the assessment of the interaction of the structuralist and institutional factors influencing environmental pollution in the oil-reliant economies. The study shows that fossil-fuel abundance triggers forces, which induce diametrically opposed effects concerning atmospheric pollution. These are the rising carbon-intensive oil extraction and processing and fossil-fueled power generation versus shrinkage of the carbon-intensive manufacturing and growth of the low-carbon tertiarization. The theoretical analysis enables compartmentalization of the essential factors, which determine GHG emissions in the respective countries. To assess the significance of the proposed theoretical framework, the study employs multivariate panel co-integration techniques and two-stage fixed effects estimations for a dataset of 38 oil-producing countries for the time period between 1960 and 2018. In contrast to the existing literature, this study drives apart from the black box approaches that employ just one omnibus variable, per capita income. 相似文献