“黄金周”对我国旅游业的影响及对策研究

旅游"黄金周"是中国现代旅游业发展中的一个独特现象。"黄金周"推动了中国旅游业的发展,尤其是国内旅游业的发展,促进了假日经济的形成,开启了中国城镇居民大众休闲旅游的新时期。然而,在旅游"黄金周"中,在巨大经济效益的背后,各种隐患也渐渐显露出来。从长远来看,不利于中国旅游的持续、快速、健康发展。"黄金周"对我国旅游业具有正反两方面的影响。因此规避其负面影响,制定相应的解决措施:确保国内旅游的和谐发展,真正实现旅游与整个社会的和谐发展。     

基于格规约辅助的MIMO系统GMD-TH预编码方案

现有的GMD-TH(Geometric Mean Decomposition-Tomlison Harashima)预编码方案在发射 端未对获得MIMO（Multiple-Input-Multiple-Output）信道增益矩阵优化,因而 其误码率和分集增益无法获得令人满意的效果。为此,在原有MIMO系统GMD-TH预编码的基础 上,提出一种基于格规约辅助的GMD-TH预编码方案。该方案采用基于格规约的算法对信道 矩阵进行优化,经过优化的信道矩阵其列向量之间具有更好的正交性并且向量的长度更短, 并且采用优化的信道矩阵提高了GMD-TH预编码MIMO系统的分集增益。仿真结果表明：相比于 传统的线性预编码方案,该预编码方案有效地提高了MIMO分集增益,相同误码率下,信噪 比降低3 dB以上,具有实用价值。     

On Corporate Virtue

This paper considers the question of virtues appropriate to a corporate actor’s moral character. A model of corporate appetites is developed by analogy with animal appetites; and the pursuit of initially virtuous corporate tendencies to an extreme degree is shown to be morally perilous. The author thus refutes a previous argument which suggested that (1) corporate virtues, unlike human virtues, need not be located on an Aristotelian mean between opposite undesirable extremes because (2) corporations do not have appetites; and (3) corporate virtues must serve the end of sustainable profit. If these disanalogies between corporate and human virtue no longer hold, then the stage is set for us to formulate a more adequate model of good corporate character that would encompass other-regarding virtues.     

一种快速的DS/FH混合扩频信号捕获方案及其性能分析

为了提高DS/FH混合扩频信号的捕获速度, 提出了一种将DS/FH 信号中三维搜索转化为 二维搜索的快速捕获方案。通过对搜索过程的详细分析,推导出在单、双驻留条件下的平均 捕获时间数学表达式以及高斯信道下系统的检测性能计算公式。理论推导与仿真结 果表明：相对于传统的捕获方式,该方案有效地缩短了系统的平均捕获时间,具有更强的抗 噪性能,适用于存在较强噪声的复杂通信环境。     

西部大开发的新特点与新机遇

我国西部大开发政策实施几年后,显现出良好的发展势头,近几年又表现出了许多新特点。西部大开发的实施,使西部地区的交通条件、电力等基础产业、城市基础设施、经济体制等软硬环境都得到了改善和提高。而中央在投资、财税、金融、土地、促进东西互动等方面的政策,决定了今后5至15年将成为西部大开发的黄金时期。在此过程中,西部现有和未来的特殊优势产业,如能源及化学工业、重要矿产开发及加工业、特色农牧业及加工业、重大装备制造业、旅游及文化产业、一些高技术产业则蕴藏着更大的商机。     

Bounds for the difference between median and mean of beta and negative binomial distributions

Summary We obtain bounds for the difference between the median and mean of the beta and negative binomial distributions using elementary methods.     

Predicting the sample mean by extreme order statistics

Summary This paper considers the prediction of the sample mean by extreme order statistics when the population distribution is known. The predictor and its mean square error are found. The problem is studied in details for the normal model.     

VERTICAL DIFFERENTIATION AND THE DISTRIBUTION OF INCOME

The paper analyses the effects of income concentration on the behaviour of a duopoly with vertical product differentiation and uncovered market. By using a trapezoid distribution, we solve explicitly for market equilibrium as a function of a mean preserving spread of the income distribution. We show that overall more concentrated incomes imply stronger product differentiation, as the presence of a large share of middle‐income consumers stimulates a price competition, whose effects are dampened through an enlargement of the quality spread. While the high‐quality advantage and market coverage increase unambiguously in the degree of income concentration, the behaviour of prices is non‐monotone in the distribution parameter.     

Mean Reversion in the Short Horizon Returns of UK Portfolios

This paper will show that short horizon stock returns for UK portfolios are more predictable than suggested by sample autocorrelation co-efficients. Four capitalisation based portfolios are constructed for the period 1976–1991. It is shown that the first order autocorrelation coefficient of monthly returns can explain no more than 10% of the variation in monthly portfolio returns. Monthly autocorrelation coefficients assume that each weekly return of the previous month contains the same amount of information. However, this will not be the case if short horizon returns contain predictable components which dissipate rapidly. In this case, the return of the most recent week would say a lot more about the future monthly portfolio return than other weeks. This suggests that when predicting future monthly portfolio returns more weight should be given to the most recent weeks of the previous month, because, the most recent weekly returns provide the most information about the subsequent months' performance. We construct a model which exploits the mean reverting characteristics of monthly portfolio returns. Using this model we forecast future monthly portfolio returns. When compared to forecasts that utilise the autocorrelation statistic the model which exploits the mean reverting characteristics of monthlyportfolio returns can forecast future returns better than the autocorrelation statistic, both in and out of sample.     

基于均方差法的郑州市土地综合承载力评价

［目的］开展土地综合承载力评价是科学编制国土空间发展战略的基础。通过构建包含水土资源承载力、经济承载力和生态承载力3个维度土地综合承载力评价指标体系,定量刻画郑州市城市土地综合承载力的特征与轨迹。［方法］运用均方差法,选取2010—2016年郑州市城市土地综合承载力评价指标,分析其土地综合承载力特征。［结果］（1）总体上,郑州市城市土地综合承载力不断增强,水土资源承载力呈现先升—降—升的动态演变特征; 经济承载力持续增长,这源于郑州市土地经济效益的大幅提升; 生态承载力呈现波动性增强的演变特征。（2）郑州市城市土地综合承载力经历了较低—中等—较高发展历程,但土地综合承载力处于低层次的较高阶段,仍有较大提升空间。（3）为提高郑州市城市土地综合承载力,应加快“多规合一”规划的编制,科学划定城市增长边界和“三生”空间,转变城市发展理念,优化发展发展路径,提升城市土地综合承载力水平。［结论］郑州市城市土地综合承载力仍有较大提升空间,应加快建立土地综合承载力扩容的有效机制。