基于繁殖规律的生猪市场供应模型

生猪生产具有发散性蛛网效应的特点,目前市场的波动正在加剧之中。基于生猪繁殖的自然规律特点,构建了一个易于分析与预测的生猪生产模型。分析显示,目前的生猪市场正在酝酿一场新的危机。导致市场波动的根源在于及时、准确信息的缺失,致使养殖者对母猪盲目的补栏。     

中心城市建设综合交通系统的经验、启示与对策——以伦敦、广州为例

通过分析伦敦的交通规划、建设、运营与管理措施,发现我国中心城市的严重交通拥堵主要源于落后的城市交通规划理念,大量引入多层高架公路进入市中心而忽视轨道交通建设,对公交优先存在认识上的误区和执行不力;城市公共交通工具营运各自为政,缺乏有效的协调与接驳;运营的低效率和管理不当,由此造成了典型的“大城市病”。根据后现代主义城市建设思想,结合当前中心城市公共交通体系建设的现状,提出了广州市综合交通体系建设的12项具体措施。     

论发展文化创意产业——基于建设国家中心城市的视角对广州文化创意产业发展的研究

本文从建设国家中心城市的视角,就广州发展文化创意产业的必要性进行了理论探讨,对广州发展文化创意产业的基础条件进行了实证分析,并提出广州大力发展文化创意产业关键在于解放与发展文化创意产业领域的生产力。     

国家中心城市文化软实力评价研究——以港京沪津穗城市为例

城市文化软实力是城市综合竞争力巨系统下的子系统,由文化核心价值水平、城市制度健全程度、城市政府管理效率及创新、城市国际化水平、城市文化中心影响力等指标组成。本文对港京沪津穗五大国家中心城市的文化软实力进行了分析,并就城市如何提升文化软实力提出了建议。     

Extended scaled prediction variance optimality for modified central composite design

Robust parameter designs (RPDs) enable the experimenter to discover how to modify the design of the product to minimize the effect due to variation from noise sources. The aim of this article is to show how this amount of work can be reduced under modified central composite design (MCCD). We propose a measure of extended scaled prediction variance (ESPV) for evaluation of RPDs on MCCD. Using these measures, we show that we can check the error or bias associated with estimating the model parameters and suggest the values of α recommended for MCCS under minimum ESPV.     

The Frisch–Waugh–Lovell theorem for the lasso and the ridge regression

The Frisch–Waugh–Lovell (FWL) (partitioned regression) theorem is essential in regression analysis. This is partly because it is quite useful to derive theoretical results. The lasso regression and the ridge regression, both of which are penalized least-squares regressions, have become popular statistical techniques. This article describes that the FWL theorem remains valid for these penalized least-squares regressions. More precisely, we demonstrate that the covariates corresponding to unpenalized regression parameters in these penalized least-squares regression can be projected out. Some other results related to the FWL theorem in such penalized least-squares regressions are also presented.     

Asymptotic behaviour of proportions of observations in random regions determined by central order statistics from stationary processes

In this paper, we show that proportions of observations that fall into a random region determined by a given Borel set and a central order statistic converge almost surely, provided that the corresponding population quantile is unique. We also describe three types of possible asymptotic behaviour of these proportions in the case of non-unique population quantile. As an application of our findings we establish limiting properties of numbers of ties with a central order statistics in a discrete sample. Our results are derived not only for independent and identically distributed observations but more generally for strictly stationary and ergodic sequences of random variables.     

Minimum variance unbiased estimation of stress–strength reliability under bivariate normal and its comparisons

In many industrial and natural phenomena, we need the probability that a component is smaller than the other component. Under a stress–strength model, this is reliability of an item. Under independent setup, there are different approaches for the estimation of such reliability. Here, estimation is considered under the dependent case. Under bi-variate setup uniformly minimum variance unbiased estimator is obtained. Also comparison with available estimator based on Maximum Likelihood Estimate (MLE) is done through Mean Square Error (MSE) and bias. Also these are compared by computing L₁ distance between their distribution functions. From this idea and numerical computations, UMVUE appears to be good.