方钢管铁尾矿再生混凝土柱抗震性能有限元分析

为解决铁尾矿再生混凝土在钢管混凝土柱中的应用问题,揭示不同参数条件下钢管铁尾矿再生混凝土柱滞回性能的变化规律,通过ABAQUS有限元软件建立了方钢管铁尾矿再生混凝土柱的数值模型。基于所建模型进行了参数化分析,研究了轴压比、宽厚比、长细比、材料强度等参数对试件抗震性能的影响。结果表明：随着轴压比由0增至0.6,承载力逐渐下降17.7%,延性逐渐下降,承载力退化速度加快;当钢材厚度不变,宽厚比由66.7减至28.6时,承载力大幅度提高61.61%,承载力退化速度放缓,耗能能力增加;随着长细比由13.16增至26.33,试件承载力下降17.5%,刚度明显下降,承载力退化速度变缓;钢材强度及混凝土强度的提升可有效提高承载力,而对试件刚度影响不大。研究证明了钢管铁尾矿再生混凝土柱具有良好的抗震性能,并可为钢管铁尾矿再生混凝土柱的应用提供理论参考。     

Efficiency and performance in gas distribution. Evidence from Brazil

This article analyses the current state of the gas distribution industry in Brazil, by identifying the main factors that determine its efficiency. In order to test the performance of the industry, we have calculated the firms’ technical efficiency during the period 2001–2009. We analyse whether some economic and technological factors as consumer density, load factor or regulation, among others, have affected the performance of this industry. We show that companies serving markets with different customer characteristics (diversification) have reached higher levels of efficiency and evolved faster. Moreover, the private ownership and price cap regulation are more efficient in relation to public ownership and cost of service regulation. These findings are important to support the improvement of the regulation of gas distribution in the Brazilian states.     

盆式橡胶支座计算机辅助设计系统

通过分析企业在盆式橡胶支座设计过程中遇到的问题,采用Visual Basic和Access对SolidWorks进行二次开发,结合盆式橡胶支座的特点,介绍二次开发流程,完成用户界面设计及实现桥梁盆式橡胶支座零件、装配体三维参数化建模,可以避免重复性工作,提高工作效率。     

On the Existence of Visual Technical Patterns in the UK Stock Market

The aim in this paper is to replicate and extend the analysis of visual technical patterns by Lo et al. (2000) using data on the UK market. A non‐parametric smoother is used to model a nonlinear trend in stock price series. Technical patterns, such as the 'head‐and‐shoulders' pattern, that are characterised by a sequence of turning points are identified in the smoothed data. Statistical tests are used to determine whether returns conditioned on the technical patterns are different from random returns and, in an extension to the analysis of Lo et al. (2000), whether they can outperform a market benchmark return. For the stocks in the FTSE 100 and FTSE 250 indices over the period 1986 to 2001, we find that technical patterns occur with different frequencies to each other and in different relativities to the frequencies found in the US market. Our extended statistical testing indicates that UK stock returns are less influenced by technical patterns than was the case for US stock returns.     

Industry,corporate, and segment effects and business performance: a non‐parametric approach

The literature investigating the degree to which firm performance is associated with industry or corporate factors has recently been subject to criticism on the grounds of both methodological shortcomings and incomplete interpretation of results. Our research goes beyond these critiques to raise more basic issues concerning the assumptions underlying variance decomposition, the methodology dominating the antecedent literature. Performance data and categorizations from a sample consistent with those employed in the recent literature are analyzed via a new non‐parametric methodology. Results here indicate that corporate factors were over an order of magnitude better predictors of business unit profit position than were industry factors—which were found not to have been significant predictors. Further, underlying performance relationships were seen to have shifted over time. A key implication of these results for researchers is that they provide additional evidence that managers can have a strategic influence on business performance. Copyright © 2003 John Wiley & Sons, Ltd.     

A Prepayment Model for the Japanese Mortgage Loan Market: Prepayment-Type-Specific Parametric Model Approach

This paper proposes a framework for construction of a prepayment model suitedto the Japanese mortgage loan market and assesses the validity of thisframework based on an empirical analysis using data from Japan. In thisframework, a model is constructed for each of three prepayment types, namely,`full prepayment', `partial prepayment', and `subrogation', using a parametricproportional hazards model, which was also employed by Schwartz and Torous(1989). Combining these three types of models allows one to take into accountthe effects of partial prepayments, which are frequently used in the Japanesemortgage market, and to simultaneously construct a model for both prepaymentand default. Time-dependent (path-dependent) covariates are introduced intothe model, which are estimated by the maximum likelihood method based on thefull likelihood that takes into account the time-dependence of the covariates.Results of the empirical analysis indicate that the hazard functions differsubstantially depending on the prepayment type. In addition, results indicatethat the fit of the model can be improved by the distinction of prepaymenttypes and the introduction of the market interest rates as path-dependentcovariates.     

CENTRAL LIMIT THEORMS IN C[0,1] FOR A CLASS OF ESTIMATORS OF A DISTRIBUTION FUNCTION

As non–parametric estimates of an unknown distribution function (d.f.) F based on i.i.d. observations X ₁ X_n with this d.f.

are used, where H _n is a sequence of d.f.'s converging weakly to the unit mass at zero. Under regularity conditions on F and the sequence ( H _n) it is shown that √_n( F _n– F ) and √_n( R _n – F ) in C [0,1] converge in distribution to a process G with G( t ) = W° ( F ( t )), where W ° is a Brownian bridge in C [0,1]. Further the a.s. uniform convergence of R., is considered and some examples are given.     

Soaring dragons,roaring tigers,growling bears

We perform a comparative analysis of regional growth and convergence in China, Russia and India over the period 1993–2003 by means of non‐parametric methods and kernel density estimates. Our results indicate that wealthy regions were largely responsible for the rapid growth in all three countries. For China and India, capital dissipation was identified as the major determinant of regional growth. In Russia, capital deepening impeded positive changes in labour productivity, leaving technological change as the only source of regional growth. Furthermore, we find that the increasing regional income inequality in all three countries was driven by technological change which more than offset the convergence resulting from capital deepening in China and India.     

Graphical Analysis of the Two Parameters logistic Function (A Methodological Proposal)

It is proposed to study the graphical representation of the parametric space of maximumlikelihood function of two parameters logistic functions, as is used in Item Response Theory. Thisproposal is made more from a point of view of understanding rather than of discovery..