森林生态效益价值会计核算研究

森林生态效益是有价值的无形资产,这些价值不仅可以计量,而且应作为会计核算的对象。随着人们日益关注环境问题,营林企业应该将纳入企业会计核算的范围。本文着重研究了不同性质的营林企业如何进行森林生态效益价值的会计核算。     

入世后中国汽车工业安全度的DEA模型估算

汽车工业长期以来是我国重点实行保护政策的产业,因而也是入世后受冲击最大的产业之一。但是这种冲击到底有多大,以及在入世后的各个年份中,这种冲击又是如何分布的?尽管有不少学者已做了一些定性分析,但是定量估算的研究则少之又少。本文首先对入世后的汽车工业发展环境进行了分析,然后对入世后汽车工业发展的关键指标数据进行了预测,最后应用DEA模型对入世后汽车工业安全度进行了估算,得出了有说服力的估算结果。     

上海股市收益与波动的周内效应研究

股市周内效应一直是金融投资者关注的焦点问题，许多学者已做了大量研究，但多数文献将收益与波动的周内效应分开来进行研究和检验，忽视了波动与收益的共生性，其结果缺乏严密性和说服力。针对这种情况，提出平行数据GARCH模型并给出了参数的极大似然估计方法，进而对上海股市收益和波动的周内效应进行检验，既反映收益与风险存在共生关系，又避免了分别判断收益和波动的周内效应所致的缺点。     

Long memory in volatilities of German stock returns

We show that there is strong evidence of long-range dependence in the volatilities of several German stock returns. This will be done by applying a method using the difference of the classical log-periodogram regression estimator for the memory parameter and of the tapered periodogram based estimator. Both estimators give similar values for the memory parameter for each series and this indicates long memory. To support our findings we apply also a methodology using the sample variance and a wavelet based estimator to the data. Also these two methods show clear evidence of long-range dependence in the volatilities of German stock returns.First version received: December 2001/Final version received: March 2003The computational assistance of Eleni Mitropoulou and Björn Stollenwerck as well as the helpful comments of two unknown referees are gratefully acknowledged. Research supported by Deutsche Forschungsgemeinschaft under SFB 475. Stock returns were obtained from Deutsche Finanzdatenbank (DFDB), Karlsruhe.     

实时OD估计中卡尔曼滤波算法研究

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。     

工程计价模式改革与投标报价的研究

适应我国加入WTO与国际工程管理接轨的需要，推行工程量清单计价模式已势在必行，广大施工企业必须及时转变观念，加强针对新的计价模式相适应的投标报价技巧研究，为企业参与投标竞争，自主报价打下良好的基础。     

Model selection in random effects models for directed graphs using approximated Bayes factors

With the development of an MCMC algorithm, Bayesian model selection for the p ₂ model for directed graphs has become possible. This paper presents an empirical exploration in using approximate Bayes factors for model selection. For a social network of Dutch secondary school pupils from different ethnic backgrounds it is investigated whether pupils report that they receive more emotional support from within their own ethnic group. Approximated Bayes factors seem to work, but considerable margins of error have to be reckoned with.     

On estimating the reliability after sequentially estimating the mean: The exponential case

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.     

长春市中心区人口疏散规模估算评析与调控策略工程

分析了长春市中心区人居环境现状特征,以此为基础,从三个不同的角度,估算了人口疏散的规模,探讨了人口疏散的时空阶段及相应的调控对策。     

Distribution Dynamics of CO<Subscript>2</Subscript> Emissions

This paper uses nonparametric methods to examine the convergence in CO₂ emissions per capita on a sample of 100 countries for the period 1966–1996. Industrial countries show a convergence pattern. However, there is little evidence of convergence for the whole sample.