两个独立复高斯随机变量乘积的相位精确分布

针对两个高斯随机变量相乘经常出现在雷达和通信系统信号处理中的情况,研究了两个独立的具有任意均值和方差的复高斯随机变量乘积的相位分布。将该相位的概率密度函数表达为一个包含Kummer函数的无穷级数,分析了该概率密度函数的收敛性及收敛速度。利用所得结果分析信道状态信息不完美情况下单天线多进制相移键控通信系统的性能,推导了该系统的符号错误率,并通过数值实验对所得结果进行了验证。     

基于树皮特征的计算机辅助植物分类与识别

文章提出一种基于小波变换系数的广义高斯密度分布形状分类算法,利用小波变换系数的统计特性,形成描述彩色图像形状特征的特征矢量,利用支撑向量机分类器进行树皮纹理图像的分类。实验证明,算法提出的描述方式能够有效体现植物树皮纹理图像的形状特征,实验结果验证了模型的有效性。     

用MATLAB进行图像绘制和处理

本论文介绍了MATLAB的特点和功能，并结合实例说明了MATLAB在图像绘制中的应用。利用MATLAB函数进行平面图形、三维图形的绘制和其他多种图像的绘制，以及对图像的各种处理。     

城市地价空间自相关分析——以宿州市为例

运用全局和局域自相关统计量及地统计学半变异函数分析方法,对宿州市商业和住宅地价的全局自相关、各项异性及局域自相关特征进行了全面分析.结果表明:在2 800m范围内,宿州市商业和住宅地价均存在较强的正自相关性且趋于高值集聚,随着相关距离的增大,地价半方差按球状模型曲线增长,自相关性逐渐减弱;在不同方向上,地价的空间自相关特征不尽相同,南北方向上的空间自相关范围要大于东西方向,但随机性较强,自相关程度较东西方向弱;在全局呈显著自相关的情形下局域地价也主要呈空间集聚格局,但部分地区表现出异质性.     

改进的细菌群体趋药性算法及应用

为使细菌群体趋药性(BCC)算法中细菌群体初始种群在解空间足够均匀,文章提出改进的BCC算法,利用均匀设计方法优选出合适的初始种群,以充分利用解空间的信息;将改进的算法,应用于函数优化上,结果表明改进后的算法在函数进化代数和寻优成功率上都有较大的提高,说明改进的方式能提高BCC算法整体运行性能.     

基于置乱变换和纠错编码技术的数字水印算法

本文提出了一种新的图像数字水印算法。利用置乱技术和纠错编码变换对二值水印图像进行预处理,将其作为水印嵌入到原始灰度图像的小波变换中,提高了算法的安全性。通过置乱变换对最佳置乱度的计算生成密钥K,生成和再现水印嵌入位置,实现了水印的盲提取。仿真和攻击检测试验表明,该算法对常见的噪声干扰和图像处理方法,如高斯噪声、滤波、JPEG压缩、剪切等具有鲁棒性。     

宏观经济与股票价格波动之间的关系研究

利用Copula模型,研究宏观经济变量与上证股指收益率之间的相关关系,在选择合适的边缘分布函数的基础上,分别建立了常相关的二元正态Copula函数、t—Copula函数、FrankCopula函数、ClaytonCopula函数以及Gum—belCopula函数模型,并且利用欧氏距离方法选择出最佳拟合Copula模型。选取2001年1月至2011年12月的月度数据作为处理对象,并利用最佳拟合模型分析宏观经济变量与上证股指收益率间相关关系及相关结构,从而揭示了中国宏观经济与股票市场之间的相关性。     

企业间知识距离测度模型及其应用研究

在借鉴知识生产函数和信息距离相关理论方法的基础上,分析了两知识主体间知识距离的影响因素,建立了知识距离测度模型。初步解决了如何测度两主体间知识距离的问题,并为企业间进行有效的知识转移提供了相关建议。     

共享单车起讫点与城市微观土地利用格局的空间关联——基于厦门岛的POI大数据

深度认知共享单车出行与土地利用格局的协调适配关系是推动城市交通绿色、可持续发展的重要前提。基于共享单车和高德地图POI数据，采用双变量K函数和协同区位商方法，探讨厦门岛共享单车起讫点与城市微观土地利用格局的空间关联与依赖关系。研究表明：从双变量K函数分析看，共享单车起讫点与不同用地之间具有较强的依赖关系，不存在阈值效应；从全局协同区位商分析来看，居住和交通用地是吸引共享单车起讫点集聚的主导因素，休闲、工作和教育用地是次要因素；从局域协同区位商分析来看，共享单车起讫点与不同用地的局域空间关联格局呈现出异质性特征，其原因在于不同用地的“人流虹吸效应”存在显著差异；其中要素集聚效应作用于西部高度关联集群的带状延伸与片状演化。     

拆迁过程中如何估算拆迁的合理费用

本文主要针对如何在城市化过程中估算改造拆迁中费用问题进行分析,使用了层次分析法通过构建比较矩阵,利用权值对拆迁费用进行合理的估算,使用加权平均法,从而使得费用的估算更为合理。     

Off-farm labour and the structure of US agriculture: the case of corn/soybean farms

While the growing importance of off-farm earnings suggests large benefits accrue to farmers from efforts to expand off-farm income opportunities, economic well being also depends on greater efficiency. To comprehensively gauge the economic health of farm operator households' off-farm income is interpreted as an output along with corn, soybeans, livestock and other crops. To accomplish this task two related methodologies were used. First, using 2000 data, a multi-activity cost function was set up to analyse labour allocation decisions within the farm operator household and also to estimate returns to scale and scope. Second, using 1996–2000 data, an input distance function approach was followed to estimate returns to scale, cost economies and technical efficiency – and the relative performance of farm operator households with and without off-farm wages and salaries compared. The cost function and input distance function results both suggest that off-farm outputs and inputs can be modelled in a multi-activity framework and involve significant economies of scope.     

Optimal Growth Models with Bounded or Unbounded Returns: A Unifying Approach

In this paper we propose a unifying approach to the study of optimal growth models with bounded or unbounded returns (above-below). Following our approach, we prove the existence of optimal solutions and show, without using the contraction method, that the value function is the unique solution to the Bellman equation for a particular class of functions. The value function can be obtained by the usual algorithm defined by the operator provided by the Bellman equation. Moreover, following our approach we obtain the recent results of F. Alvarez and N. Stokey (1998, J. Econ. Theory82, 167-189) as well as the well-known results. Journal of Economic Literature Classification numbers: C61, 041.     

基于分类最优原理的小企业信用风险评价

基于分类最优原理进行小企业信用风险评价,即以违约样本和非违约样本的重心距离最大为目标函数,以指标的三角模糊熵及变异系数组成的指标权重区间为约束条件,确定指标的组合权重,评价小企业信用风险状况。应用实例结果表明:利用该方法评价小企业的信用风险,能够更好地区分违约客户与非违约客户,使模型的判别精度有所提高。     

论现代远程教育在基层党校的地位和作用

当前搞好基层党校远程教育意义重大而深远,要充分发挥远程教育在党员干部教育中的地位和作用,努力把此项工作真正运用到教学的过程之中.     

NUMERICAL SIMULATION OF NONOPTIMAL DYNAMIC EQUILIBRIUM MODELS

In this article, we propose a recursive equilibrium algorithm for the numerical simulation of nonoptimal dynamic economies. This algorithm builds upon a convergent operator over an expanded set of state variables. The fixed point of this operator defines the set of all Markovian equilibria. We study approximation properties of the operator. We also apply our recursive equilibrium algorithm to various models with heterogeneous agents, incomplete financial markets, endogenous and exogenous borrowing constraints, taxes, and money.     

Technical and scale efficiencies of meat goat farms in the USA

This study determines i) scale and technical efficiencies, ii) marginal productive contributions for inputs and outputs and iii) efficiency drivers of meat goat farms in the USA. We estimate an input distance function (IDF) using a stochastic production frontier (SPF) technique. The average technical efficiency (TE) for the USA meat goat whole farm was 0.74. The operator education level, percentage of annual net farm income from the goat operation, regional differences and holding of an off farm job are the efficiency drivers of USA meat goat farms. We find increasing returns to scale (RTS) for USA meat goat farms. Our results suggest that USA meat goat farms can be scale efficient if their optimal size of operation is greater than approximately 64 goats or greater than 40 breeding does. Empirical Monte Carlo (MC) simulation techniques show the consistency of finite-sample properties for the input distance function.     

主客观数据融合的热点园亭景观意象 感知评价研究

景观意象感知是传播中国古典园林文化的重要途 径,但对其进行定量评价的方法尚不多见。首先以苏州四大古 典园林的园亭为研究样本,遵循意象传播中主客体交流的规 律,综合利用游客GPS数据和问卷数据挖掘游客感知热点园 亭;然后采用主客观融合的综合赋权方法,对热点园亭的景观 意象因子进行权重解析和综合评价;最后建立园亭景观意象感 知评价体系,并探明园亭景观意象感知的形成与传播途径,揭 示园亭景观意象感知评价的意义。结果表明：提出的评价体系 能够较好量化游客对于园亭景观意象要素的主观认知,其中的 意象因子感知权重与游客感知满意度有较高的一致性。在风景 园林设计实践中,可运用该评价体系对景观意象要素进行精准 设计,进而提升游客感知满意度。     

Roadmapping for prioritisation of smartphone feature requirements based on user experiences

Since the life cycle of smartphones is becoming shorter, users are demanding new and improved smartphone features for updated smartphones, but it is difficult to know which features are the most important to users. In Internet user communities, users increasingly review smartphone functions and share information about their experiences such as complaints, problems, and satisfaction, and these user experiences have been fruitful sources for manufacturers that lead to smartphone improvements. Focusing on these user experiences, this paper proposes a systematic roadmapping process including prioritisation of smartphone feature requirements. By prioritising smartphone feature requirements, new and improved versions of smartphones that reflect user needs can be planned based on a product–market roadmap. The systematic approach consists of three parts: user-driven quality function deployment (QFD), a frequent pattern (FP)-tree algorithm, and a product–market roadmap. First, we collected data extracted from text mining in Internet user communities to construct a user-driven QFD. Second, using user experiences related to smartphone features, we applied the FP-tree algorithm to algorithmically derive a priority list of smartphone feature requirements. Finally, based on the result of the FP-tree of smartphones, we proposed guidelines to construct a product–market roadmap. It is expected that a versioning strategy can be formulated through this prioritised product–market roadmap. Furthermore, covering each step from data collection to roadmapping, this study suggests a systematic process for prioritisation of smartphone feature requirements based on user experiences.     

Notes on some inequalities in economics

Summary. Inequalities created by relating gauge (distance) functions and their dual support functions have been used in economics and operations research/management science to measure efficiency and productivity. The most familiar example is the Farrell (1957) measure of cost efficiency and its decomposition into technical and allocative components, which can be shown to be an application of the Mahler (1939) inequalities, although Farrell was probably unaware of the connection. In this short paper we add to this literature by providing explicit relationships between distance functions and support functions to form five different inequalities. These inequalities are derived from three support functions: the cost function, the revenue function and the profit function, and three gauge (distance) functions: the input distance function, the output distance function and the directional (technology) distance function.     

Measuring sustainability performance for China: A sequential generalized directional distance function approach

This paper aims to present certain composite sustainability efficiency indicators for China based on a sequential generalized directional distance function. This approach can measure the sustainability performance of a country with diverse outputs, nature of technologies, and non-radial slacks. First, we propose the concept of a generalized directional distance function under a sequential environmental production technology. Second, we develop several standardized composite indicators related to sustainability performance. We then estimate the sequential generalized directional distance function based on a series of sequential data envelopment analysis models. Finally, we empirically examine regions in China using the proposed model and present some implications based on the empirical results.