增长曲线模型非齐次线性估计的可容许性

讨论增长曲线模型Y =X1BX2 +ε中回归矩阵B的函数C1BC2 的估计L1YL2 +A ,在矩阵损失 (LT2 L1)Y +A - (ST2 XT2 S1X1)B (LT2 L1)Y +A - (ST2 XT2 S1X1)B T 下 ,我们得到了非齐次线性估计L1YL2 +A在非齐次线性估计类Г ={L1YL2 +A|L1:t×p ,L2 ;n×n ,A :t×s均为已知实阵 }中可容许的充要条件 :L1YL2在Г0 ={L1YL2 |L1:t×p ,L2 :n×s均为已知实阵 }中容许且当LT2 XT2 L1X1=ST2 XT2 S1X1时有A =0。     

Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.     

上海市空气污染造成人群健康经济损失的研究

文章通过对上海市空气污染季节性状况的描述 ,分析了各种污染物的污染程度和变化趋势 ,并利用对上海某市级医院的实地调查数据 ,对空气污染物与医院呼吸系统疾病患者日门诊量之间的相关关系进行研讨 ,建立了多元分析模型 ,探讨了患者健康经济损失的计量方法 ,并对由空气污染造成呼吸系统疾病患者健康经济损失进行了估算。研究表明 ,在其他条件不变的情况下 ,NOX 日指数每增长 10 % ,被调查医院呼吸系统疾病患者的日门诊人次增加 7 7人次 ,而这些疾病患者由于患病产生的年度健康经济损失为 2 11万元。据此作保守的推断估计 ,上海市一年内因NOX 超标而发生的呼吸系统疾病门诊行为造成的健康经济损失可以达到 4 2亿元。同样 ,SO2 和TSP造成门诊患者的健康经济损失分别为 1 5亿元和 0 86亿元     

“He Survives Everything”: A Latency-Aged Child with Play Disruption in the Face of Trauma and Early Object Loss

It is hypothesized that trauma and early object loss result in the arrest of the normal and healthy progression of a child's development and also disrupts a child's capacity to engage in symbolic play. In therapy, over time, with a constant object, a latency-aged child was able to re-enact early trauma and loss, make substantial gains in development, and begin to play in a symbolic and expressive way.     

Loss functions for estimation of extrema with an application to disease mapping

It is often of interest to find the maximum or near maxima among a set of vector‐valued parameters in a statistical model; in the case of disease mapping, for example, these correspond to relative‐risk “hotspots” where public‐health intervention may be needed. The general problem is one of estimating nonlinear functions of the ensemble of relative risks, but biased estimates result if posterior means are simply substituted into these nonlinear functions. The authors obtain better estimates of extrema from a new, weighted ranks squared error loss function. The derivation of these Bayes estimators assumes a hidden‐Markov random‐field model for relative risks, and their behaviour is illustrated with real and simulated data.     

我国建筑消防现状

近年来 ,中国城市建筑火灾发生率呈上升趋势 ,仅 1999年 ,全国共发生建筑火灾 18万起 ,比前一年增长 4 1% ;死亡 2 70 0多人 ,比前一年增长 15 % ,直接经济损失多达 14亿元。     

动机与第二语言习得

动机是学习第二语言成就大小的重要因素之一。很多研究实验已经证明动机在人类认知过程中起非常关键性的作用。本文打算对动机，融合性动机和功用性动机及其与第二语言习得的关系做一些探讨     

Improving on truncated linear estimates of exponential and gamma scale parameters

We consider the problem of estimating the scale parameter of an exponential or a gamma distribution under squared error loss when the scale parameter θ is known to be greater than some fixed value θ₀. Natural estimators in this setting include truncated linear functions of the sufficient statistic. Such estimators are typically inadmissible, but explicit improvements seem difficult to find. Some are presented here. A particularly interesting finding is that estimators which are admissible in the untruncated problem which take values only in the interior of the truncated parameter space are found to be inadmissible for the truncated problem.     

知识型员工流失的深层研究——基于心理契约的视角

知识型员工由于其地位和作用的特殊性,一直是企业竞争的主要对象,其流动率也一直较高。知识型员工流失在很大程度上是心理契约违背的必然结果,因此,重构和优化心理契约至关重要。具体而言,在招聘、入职、变动和离职四个阶段,企业应分别采取真实岗位预视、建立动态档案、加强沟通、及时补偿和离职面谈等措施,防止知识型员工流失。     

金融知识获取圈层对农户农地抵押贷款参与的影响研究——基于失地风险感知的中介效应分析

积极稳妥推广农地抵押贷款融资业务,持续深化农村土地资产与金融资源的有机衔接是完善金融服务乡村振兴战略的关键内容,深入探究农户金融知识获取的人际圈层来源以及失地风险感知因素对完善农地抵押贷款相关制度建设具有重要意义。文章首先理论阐释了金融知识获取圈层、失地风险感知对农户农地抵押贷款参与的影响,详细剖析了农户失地风险感知的中介机理;然后采用因子分析法测度金融知识获取圈层变量,提取4个公共因子分别界定为亲属关系圈、朋友关系圈、乡邻关系圈和机构参与圈;最后以陕西、宁夏、山东三省农地抵押贷款试点地区1 312户农户调查数据为样本,利用Logit模型和Bootstrap中介效应检验方法,实证分析了金融知识获取圈层、失地风险感知对农户农地抵押贷款参与的影响,并揭示了失地风险感知的中介效应类型和数值大小。研究结果显示：金融知识获取圈层正向促进农户农地抵押贷款参与,其中金融知识获取亲属关系圈的促进作用大于机构参与圈;金融知识获取圈层负向影响农户失地风险感知,机构参与圈的影响最大,亲属关系圈次之,朋友关系圈最小;在四个金融知识获取圈层下,失地风险感知均对农户农地抵押贷款参与具有负向影响;失地风险感知在金融...