架空输电线路接地装置设计中的几个要点

架空输电线路的接地问题看似简单,可是操作起来却是非常复杂非常重要的问题,它直接关系到人身安全和设备安全,现在随着电力系统的发展,电网规模不断扩大,接地短路电流越来越大,对接地技术要求越来越高.文章简单介绍了架空线路杆塔的接地的设计方法和降低接地电阻的技术措施,以供探讨.     

架空输电线路接地装置设计中的几个要点

架空输电线路的接地问题看似简单,可是操作起来却是非常复杂非常重要的问题,它直接关系到人身安全和设备安全,现在随着电力系统的发展,电网规模不断扩大,接地短路电流越来越大,对接地技术要求越来越高。文章简单介绍了架空线路杆塔的接地的设计方法和降低接地电阻的技术措施,以供探讨。     

总承包工程项目管理要点分析

建筑行业实现了管理层和施工层的分离,大量的工程承包队伍出现。文章对我国总承包工程项目的特点进行分析,然后,依次从设计、采购、施工管理中进行深入探究。     

Some results on general assumptions about the existence of economic equilibrium

In the present paper we maximally use the possibilities provided by the Nash approach and the Kakutani fixed point theorem for proving the existence of an economic equilibrium. We obtain a general existence theorem which does not require a special form for income distribution functions and producer's objectives, independence of consumers' tastes, ordered preference and zero degree homogeneous price dependence. The role of the non-satiation assumption becomes more clear.     

Some general results for moments in bivariate distributions

The purpose of this paper is to present a closed formula to compute the moments of a general function from the knowledge of its bivariate survival function. The result is derived by utilizing an integration by parts formula for two variables, which is not readily available in the literature. Many of the existing results are obtained as special cases. Finally, two examples are presented to illustrate the results. In both the examples, mixed moments as well as moments for the series system and parallel system are obtained. The integration by parts formula in two variables, derived here, is of interest in its own right and we hope that it will be useful in other investigations. The integration by parts formula in two variables is derived as a special case of a general formula in n variables.     

A general framework for approximate sampling with an application to generating points on the boundary of bounded convex regions

We consider the problem of generating a sample of points according to some given probability distribution over some region. We give a general framework for constructing approximate sampling algorithms based on the theory of Markov chains. In particular, we show how it can be proven that a Markov chain has a limiting distribution. We apply these results to prove convergence for a class of so-called Shake-and-Bake algorithms, which can be used to approximate any absolutely continuous distribution over the boundary of a full-dimensional convex body.     

On the measurement of benefits in an urban context: Some general equilibrium issues

The validity of using local market data to measure the benefits associated with policies adopted in an urban area is investigated. It is shown that the rest of the world is affected by taxing decisions undertaken in a single urban area, so that local data cannot perfectly measure the welfare effects of a policy change. Specifically, the fact that the willingness to pay for a tax increase is positive in the rest of the world suggests that cost-benefit analyses which do not account for the rest of the world may be biased.     

Some results on constructing general minimum lower order confounding 2^{n-m} designs for n\le 2^{n-m-2}

Zhang et al. (Stat Sinica 18:1689–1705, 2008) introduced an aliased effect-number pattern for two-level regular designs and proposed a general minimum lower-order confounding (GMC) criterion for choosing optimal designs. All the GMC \(2^{n-m}\) designs with \(N/4+1\le n\le N-1\) were constructed by Li et al. (Stat Sinica 21:1571–1589, 2011), Zhang and Cheng (J Stat Plan Inference 140:1719–1730, 2010) and Cheng and Zhang (J Stat Plan Inference 140:2384–2394, 2010), where \(N=2^{n-m}\) is run number and \(n\) is factor number. In this paper, we first study some further properties of GMC design, then we construct all the GMC \(2^{n-m}\) designs respectively with the three parameter cases of \(n\le N-1\) : (i) \(m\le 4\) , (ii) \(m\ge 5\) and \(n=(2^m-1)u+r\) for \(u>0\) and \(r=0,1,2\) , and (iii) \(m\ge 5\) and \(n=(2^m-1)u+r\) for \(u\ge 0\) and \(r=2^m-3,2^m-2\) .     

A note on the uniform distribution on the arcsin points

In his book Pukelsheim [8] pointed out that designs supported at the arcsin points are very efficient for the statistical inference in a polynomial regression model. In this note we determine the canonical moments of a class of distributions which have nearly equal weights at the arcsin points. The class contains theD-optimal arcsin support design and theD ₁-optimal design for a polynomial regression. The results allow explicit representations ofD-, andD ₁-efficiencies of these designs in all polynomial models with a degree less than the number of support points of the design.     

Contact points and flash points: Conceptualizing the use of justice mechanisms in the performance appraisal interview

There has been a great deal of performance evaluation research, but little has been directed toward understanding subordinate responses to this process and developing ways to manage these responses. In contrast, the justice literature has identified mechanisms that directly influence recipient responses to organizational decisions. The present paper attempts to integrate justice theory and research into the performance appraisal interview. A conceptual model is presented that examines the relationship between three key justice mechanisms in the performance appraisal interview. Propositions are presented regarding the influence of these mechanisms using contact points (episodes where justice mechanisms are expected) and flash points (combinations of justice mechanisms that might lead to problems) as a basis for understanding how justice works in this context. Research is recommended to test these propositions. Implications for conducting performance appraisal interviews are discussed.     

对客户实施用电检查要点的探讨

客户配电设施、设备的设计、安装及运行维护管理,直接影响着客户安全生产、经济利益及电力系统的安全运行。文章通过对客户用电检查技术要点的分析,对供电企业开展用电检查工作的方法与关键点进行了探讨。     

Predicting turning points in the housing market

We identify leading indicators of changes in the housing market and compare their performance in predicting turning points. Being able to predict turning points is of importance to the home building industry, homeowners, and makers of housing policy. Our leading indicators include the Wells Fargo/NAHB Housing Market Index, two of its forward looking components, and an index of consumer sentiment regarding purchasing a home. Our comparison tests include Granger causality and a Bayesian predictor of the probability of a turning point. We find that the measure of consumer sentiment performs relatively well compared to the HMI in predicting home permits, housing starts, and new home sales.     

预制混凝土柱吊装施工要点分析

预制混凝土排架结构在重工业厂房中广泛应用,柱强度高,刚度大,吊装方便,施工周期短,是一种很有发展前途的结构体系。文章主要以某厂房的混凝土排架吊装施工为例,对混凝土柱吊装施工中的几个要点进行了分析。     

Evaluating the efficiency of municipalities in the presence of unobserved heterogeneity

Journal of Productivity Analysis - The paper applies some of the latest advances of probabilistic approach to account directly for unobserved heterogeneity in the estimation of efficiency measures...     

Testing the proportional hazards assumption in the presence of unmeasured heterogeneity

This paper develops a discrete-time hazard model which accounts for unmeasured hetergeneity while allowing the coefficients of the regressors to vary over time. Sufficient conditions for nonparametric identifiability of the unmeasured heterogeneity distribution are derived. Testing for time-varying coefficients in this model is, under suitable conditions, equivalent to testing the proportionality assumption of the underlying continuous-time hazard model. Some Monte Carlo evidence is presented regarding the small-sample properties of this test. As an illustration, these tests are applied to the joblessness durations of displaced workers.     

Modelling heterogeneity and dynamics in the volatility of individual wages

This paper presents a model for the heterogeneity and dynamics of the conditional mean and conditional variance of individual wages. A bias‐corrected likelihood approach, which reduces the estimation bias to a term of order 1/T², is used for estimation and inference. The small‐sample performance of the proposed estimator is investigated in a Monte Carlo study. The simulation results show that the bias of the maximum likelihood estimator is substantially corrected for designs calibrated to the data used in the empirical analysis, drawn from the PSID. The empirical results show that it is important to account for individual unobserved heterogeneity and dynamics in the variance, and that the latter is driven by job mobility. The model also explains the non‐normality observed in log‐wage data. Copyright © 2010 John Wiley & Sons, Ltd.     

浅谈装修工程质量控制要点

要使施工质量得到保证,除了施工中使用合格的材料、优秀的施工人员外,最主要是严格按照相关国家规范和有关标准的要求来完成每一道工序,严禁偷工减料,狠抓施工过程的质量控制。文章对建筑装饰装修工程的质量控制进行了简要论述。     

基于J2EE的学校后勤管理系统关键技术研究

针对桂林电子科技大学现有后勤管理系统相对落后的问题,采用B/S架构,运用开源框架Struts-Spring-Hibernate构建基于J2EE的高校后勤管理系统。该系统将开源框架与Ajax技术相结合,可实现系统的异步提交,减轻网络通信和服务器端的负担;以后勤管理数据为研究对象,通过数据仓库、OLAP、数据挖掘技术的综合运用发现后勤管理系统中的有用信息,为管理高层提供辅助决策支持,具有较强的实用价值。