论近代粤丝出口的市场规律和特征

由于亚热带季风气候的影响 ,以蚕丝生产为基础的粤丝出口在量与质等方面都呈现出明显的季节变化 :一般 4、5月份第一造新丝上市 ,但质、量欠佳 ,对出口贸易影响不大 ;6月份第四造生丝质、量最优 ,形成出口交易高潮 ;前后多造蚕丝相继上市 ,使交易旺期持续到 10月份。同时在近代社会背景下 ,粤丝价格深受国际市场的支配和影响 ,并被欧美列强恣意操纵 ;其变化在宏观上形成由涨到落的趋势 ,微观上则呈现出波动频繁等特点     

人类抽象劳动:知识经济时代商品价值的唯一源泉

科技的发展 ,知识经济时代的到来 ,生产力、劳动效率空前提高 ,劳动者素质要求显著改变 ,对商品价值形成和单位时间商品价值量产生了巨大影响 ,但并有改变价值实体——人类抽象劳动的疑结。     

盾构重叠隧道施工力学行为分析

我国地铁建设的快速发展,就涉及地铁建设中上下重叠隧道的相关问题进行研究。利用三维有限元方法并结合广州某重叠盾构施工的地铁工程实例分析了下洞（左线）隧道受上洞（右线）开挖产生的影响范围、上洞盾构在不同推进力下对下洞位移、应力和应变产生的影响和下洞局部范围在有临时支护条件下随上洞开挖产生位移和内力变化。分析表明：下洞隧道结构受上洞盾构施工的影响表示形式为上洞盾构前方的下洞结构存在向下桡曲,而在后方则向上隆起,直至趋于一个定值,其中下洞盾构机的盾尾需在上洞盾构机盾头前方的50 m;上洞隧道在推进过程中,推进力是     

利润质：企业经营目标新概念

在现有的经济学与管理学中,企业经营是以利润量的最大化为目标的,然而利润量并不是衡量企业管理水平与经营业绩的唯一指标,也难以反映企业对经济增长与福利改进的真实贡献。因此,我们有必要切入利润质这一新概念,并在此基础上构建一个能更真实地反映管理水平、经营业绩及发展前景的指标体系。     

Inference Based on Order Statistics from the Generalized Pareto Distribution and Application

ABSTRACT

In this article, we derive exact explicit expressions for the single, double, triple, and quadruple moments of order statistics from the generalized Pareto distribution (GPD). Also, we obtain the best linear unbiased estimates of the location and scale parameters (BLUE's) of the GPD. We then use these results to determine the mean, variance, and coefficients of skewness and kurtosis of certain linear functions of order statistics. These are then utilized to develop approximate confidence intervals for the generalized Pareto parameters using Edgeworth approximation and compare them with those based on Monte Carlo simulations. To show the usefulness of our results, we also present a numerical example. Finally, we give an application to real data.     

Exact Inference for the pth-Quantile and the Reliability of the Two-Parameter Exponential Distribution with Singly Type II Censoring: A Standard Approach

Starting from a standard pivot, exact inference for the pth-quantile and for the reliability of the two-parameter exponential distribution in case of singly Type II censored samples is developed in this article. Fernandez (2007 Fernandez , A. J. ( 2007 ). On calculating generalized confidence intervals for the two-parameter exponential reliability function . Statistics 41 : 129 – 135 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) first obtained some of the results proposed in this article, but, differently from what are proposed here, and developed his theory starting from a generalized pivot. An illustrative example shows that, with the expressions proposed in this article, it is also possible to overcome some shortcomings raising from the formulas by Fernandez (2007 Fernandez , A. J. ( 2007 ). On calculating generalized confidence intervals for the two-parameter exponential reliability function . Statistics 41 : 129 – 135 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). Finally, a new expression for the moments of the pivot is obtained.     

Improved bootstrap confidence intervals in certain toxicological experiments

The bootstrap, the jackknife, and classical methods are compared through their confidence intervals for the proportion of affected fetuses in a common type of animal experiment. Specifically, suppose that for the ith of M pregnant animals, there are x _i affected fetuses out of n _i total in the litter. The conditional distribution of x _i given n _i is sometimes modeled as binomial (n _i p _i ), where p _i is a realization from some unknown continuous density. The p _i are not observable and it is of interest in some toxicological experiments to find confidence intervals for E(p). Theory suggests that the proposed parametric bootstrap should produce higher order agreement between the nominal and actual coverage than that exhibited by the usual nonparametric bootstrap. Some simulation results provide additional evidence of this superiority of the modified parametric bootstrap over the jack-knife and classical approaches. The proposed resampling is flexible enough to handle a more general model allowing correlation between p _i and n _i .     

Confidence Intervals of Performance Measures for an M/G/1 Queueing System

In this article, we discuss constructing confidence intervals (CIs) of performance measures for an M/G/1 queueing system. Fiducial empirical distribution is applied to estimate the service time distribution. We construct fiducial empirical quantities (FEQs) for the performance measures. The relationship between generalized pivotal quantity and fiducial empirical quantity is illustrated. We also present numerical examples to show that the FEQs can yield new CIs dominate the bootstrap CIs in relative coverage (defined as the ratio of coverage probability to average length of CI) for performance measures of an M/G/1 queueing system in most of the cases.     

Optimizing Customer Forecasts for Forecast‐Commitment Contracts

We study a “Forecast‐Commitment” contract motivated by a manufacturer's desire to provide good service in the form of delivery commitments in exchange for reasonable forecasts and a purchase commitment from the customer. The customer provides a forecast for a future order and a guarantee to purchase a portion of it. In return, the supplier commits to satisfy some or all of the forecast. The supplier pays penalties for shortfalls of the commitment quantity from the forecast, and for shortfalls of the delivered quantity from the customer's final order (not exceeding the commitment quantity). These penalties allow differential service among customers. In Durango‐Cohen and Yano (2006), we analyzed the supplier's problem for a given customer forecast. In this paper, we analyze the customer's problem under symmetric information, both when the customer is honest and when he strategically orders more than his demand when doing so is advantageous. We show that the customer gains little from lying, so the supplier can use his control over the contract parameters to encourage honesty. When the customer is honest, the contract achieves (near‐)coordination of the supply chain in a great majority of instances, and thus provides both excellent performance and flexibility in structuring contracts.     

机电控制课程体系教学改革研究与实践

从机电控制课程内容体系、教学组织形式和教学方法上进行了教学改革的探索,目的是加强课程建设、培养学生的创新能力,增强学生发现问题、分析问题和解决问题的能力。