基于延迟自相关特性的码速率测量技术

通信信号的识别与解调是通信侦察的重要研究内容，在通常情况下，通信信号的很多参数并不知道。本文介绍了一种基于通信信号码延迟自相关特性的码速率测量技术，并给出了码速率测量理论分析及基于硬件的实现技术，仿真和实验结果表明本方案具有较高的测量性能。     

Assessment of Interjudge Reliability in the Open-Ended Questions Coding Process

In the process of coding open-ended questions, the evaluation of interjudge reliability is a critical issue. In this paper, using real data, the behavior of three coefficients of reliability among coders, Cohen’s K, Krippendorff’s α and Perreault and Leigh’s I _r are patterned, in terms of the number of judges involved and the categories of answer defined. The outcome underlines the importance of both variables in the valuations of interjudge reliability, as well as the higher adequacy of Perreault and Leigh’s I _r and Krippendorff’s α for marketing and opinion research.     

探索性空间数据分析模型研究

探索性空间数据分析是空间经济计量学的一个重要领域。解释与空间位置相关的空间依赖、空间关联或空间自相关现象。目前在国内外的应用也越来越广泛。本文就探索性空间数据分析模型进行了综合介绍，并分析了其在未来的应用前景。     

上市公司可持续发展评价体系构建

目前,我国上市公司业绩评价体系门类繁多,但专门评价可持续发展能力的指标体系尚停留在探索阶段。本文在现有研究基础上,构建了上市公司可持续发展的实现模型,并选取定量指标,采用变异系数总指数法赋予权重,建立了上市公司可持续发展评价体系。以2003年我国电子行业上市公司为样本进行检验,结果发现,其结果与《2003年度中国上市公司业绩评价报告》具有一致性。     

Technological change in energy systems: Learning curves, logistic curves and input-output coefficients

Learning curves have recently been widely adopted in climate-economy models to incorporate endogenous change of energy technologies, replacing the conventional assumption of an autonomous energy efficiency improvement. However, there has been little consideration of the credibility of the learning curve. The current trend that many important energy and climate change policy analyses rely on the learning curve means that it is of great importance to critically examine the basis for learning curves. Here, we analyse the use of learning curves in energy technology, usually implemented as a simple power function. We find that the learning curve cannot separate the effects of price and technological change, cannot reflect continuous and qualitative change of both conventional and emerging energy technologies, cannot help to determine the time paths of technological investment, and misses the central role of R&D activity in driving technological change. We argue that a logistic curve of improving performance modified to include R&D activity as a driving variable can better describe the cost reductions in energy technologies. Furthermore, we demonstrate that the top-down Leontief technology can incorporate the bottom-up technologies that improve along either the learning curve or the logistic curve, through changing input-output coefficients. An application to UK wind power illustrates that the logistic curve fits the observed data better and implies greater potential for cost reduction than the learning curve does.     

Asymptotic confidence bands for the estimated autocovariance and autocorrelation functions of vector autoregressive models

This paper provides closed-form formulae for computing the asymptotic covariance matrices of the estimated autocovariance and autocorrelation functions of stable VAR models by means of the delta method. These covariance matrices can be used to construct asymptotic confidence bands for the estimated autocovariance and autocorrelation functions to assess the underlying estimation uncertainty. The usefulness of the formulae for empirical work is illustrated by an application to inflation and output gap data for the U.S. economy indicating the existence of a significant short-run Phillips-curve tradeoff.First version received: November 2002/Final version received: September 2003     

我国城镇居民收入分配差距的实证研究

笔者首先计算了几种度量收入分配差距的指标,从不同角度的分析得到了我国城镇居民收入分配差距不断扩大的结论;其次估计了我国城镇居民的基尼系数.通过计量经济模型,检验了高、中、低各阶层可支配收入与收入分配差距之间的关系,得出结论:增加中低收入阶层的可支配收入,遏制高收入阶层可支配收入,可以减小基尼系数,从而降低收入分配差距;进一步通过模型发现,我国发达地区的经济发展和收入分配差距呈现出倒U型规律,说明经济发展达到一定水平,收入分配差距有望缩小.     

Identifying the internal structure evolution of urban built-up land sprawl (UBLS) from a composite structure perspective: A case study of the Beijing metropolitan area,China

Differences in the internal composite structure during urban built-up land sprawl (UBLS) will generate different effects, and thus, a city’s spatial structure has important bearings on urban sustainability. This study investigates the spatial and temporal characteristics of the internal structure and allocation relationship of UBLS using multivariate spatial correlation and the Weaver-Tomas composite coefficient based on site data of granted built-up land parcels. Moreover, the composite structure evolution process of UBLS and its driving mechanism are examined in this study. The results reveal that the amount structure of the three types of UBLS (i.e. industrial land sprawl, residential land sprawl and commercial land sprawl) tended to be balanced during the study period. Following the transformation and upgrade of the urban industry structure, the overall composite structure of UBLS ranged from single residential land-use structure (Res.) to industrial-residential land-use structure (Ind.-Res.) In the early period of land marketization, the marketization land granting mechanism caused low spatial correlation between the various types of UBLS and a single composite structure, i.e. Res., single commercial land-use structure (Com.), and residential-commercial land-use structure (Res.-Com.). Subsequently, a dual-driving force including the market economy and government interventions caused a relatively high degree of spatial correlation and a multiple composite structure, i.e. Ind.-Res. and industrial-residential-commercial land-use structure (Ind.-Res.-Com.). However, the evolution characteristics of the composite structure in various regions illustrate some problems, such as the spatial isomorphism phenomenon of the composite structure and the dislocation of urban built-up land allocation. The urban internal built-up land spatial layout pattern is the embodiment of two dominant driving forces, the market and the government, interacting with each other according to natural and socioeconomic conditions. Therefore, we suggest that it is necessary to reform the future urban built-up land granting mechanism based on market guidance, and the composite structure of UBLS should be adjusted according to the regional function. The government should reinforce the macro-control of land-use planning for the dispersed granted land parcels so as to optimize the urban land-use structure.