旅游区域：对四种常见“区域旅游空间结构理论”的质疑初探

国内外形势使我国旅游发展模式亟需转型,区域旅游竞合成为时代必然。区域旅游竞合以合理的空间结构为先导,我国区域旅游空间结构理论研究和应用尚处于初级阶段,其中以四种常见理论为主流。通过对旅游区域本质和表现形式及其内在关系的深刻解析,发现旅游区域的四维空间形态富有特殊性或个性,形成对“四理论”的尖锐质疑。“四理论”并未深入分析区域个性,其所适用的“区域”有特定的条件限制,故绝不能直接套用。     

An Overview of Normal Theory Structural Measurement Error Models

This paper gives an introduction and overview to the often under‐used measurement error model. The purpose is to provide a simple summary of problems that arise from measurement error and of the solutions that have been proposed. We start by describing how measurement error models occur in real‐world situations. Then we proceed with defining the measurement error model, initially introducing the multivariate form of the model, and then, starting with the simplest form of the model thoroughly discuss its features and solutions to the problems introduced due to measurement error. We discuss higher‐dimensional and more advanced forms of the model and give a brief numerical illustration.     

一种基于自适应阵列天线的波束赋形算法

自适应阵列天线中的数字波束赋形(DBF)技术是智能天线数字信号处理部分的核心.提出了一种可用于自适应阵列波束赋形的SMI-LMS算法--由SMI(采样协方差矩阵求逆)算法决定LMS(最小均方)算法的初始权向量.该算法充分结合了SMI算法收敛速度快和LMS算法稳态误差小的优点,能在较强干扰环境下,确保权向量的快速收敛和跟踪速度.与传统的LMS算法相比,SMI-LMS算法具有良好的收敛性能、较快的跟踪速度和较小的输出误差,并可以有效改善自适应方向图的副瓣性能.仿真结果验证了该结论.     

Avoiding Mis-estimation of the CES Function: Unit Matters

ABSTRACT

We demonstrate that unit errors of measurement will lead to significant biases in estimating the constant elasticity of substitution (CES) function. Monte-Carlo simulations show that estimation results tend to reach Cobb–Douglas (CD) functions or extreme values if units of input variables are incorrectly used. To avoid this problem, we suggest adding an overall efficiency parameter and a unit correction parameter which is similar to biased technological change parameter when estimating CES functions. Any unit error of measurement can be captured by these two parameters while allowing researchers to get unbiased estimation results of other parameters.     

Rolling out of fibre optic networks in intermediate versus urban areas: An exploratory spatial analysis in the Netherlands

Within the growing literature on broadband development, much research has focused on infrastructure competition and spatial effects driving investment incentives in broadband provision. However, less attention has been paid to the geographical factors explaining very high capacity fibre based network rollout. The purpose of this paper is to examine these geographical effects of rollout of these networks by utilizing basic data mining techniques in conjunction with exploratory spatial data analysis. In explaining the rollout of these networks, the paper derives from the literature a geographical model on broadband provision and examines it empirically by focusing on the spatial and temporal effects driving very high capacity fibre-based network development in the Netherlands. The paper confirms previous research on market uncertainty and the techno-economics of broadband development, but shows, in addition, that more specific factors related to local effects and demand uncertainty are vital in explaining the rollout of very high capacity fibre-based network.     

Informal employment in Poland: an empirical spatial analysis

The main goal of our article is to bridge the gap in the regional analysis of informal employment in Poland and in particular to indicate the propensity for informal work in the working-age population, to test if informal activities are typical for marginalized people (less educated, unemployed, older) and to identify the regional and spatial heterogeneity in the propensity. We use data from the ‘Human Capital Balance 2010–2014’ survey. Results indicate a strong relationship between the probability of informal work and age, sex and labour force status. Moreover, a strong spatial dependency can be observed.     

地区市域经济发展趋势及影响机制研究——以中部地区为例

为了研究在新的经济战略格局中,中部地区经济逐渐在全国区域经济发展格局,以市域为研究单元,利用空间自相关性分析和空间计量经济分析方法进行实证研究。结果表明:中部地区的市域经济发展具有明显的空间正相关性,且空间集聚特征呈"U"型的演变趋势;区域投资水平是促进中部地区经济发展的有效手段;河南和山西两省应根据自身特点合理优化经济结构通过各种产业协作促进经济发展;湖北省的地方财政支出政策有待改进和优化;湖南省需要合理优化市场规模和调整财政支出政策;江西省需要发展具有江西特色的经济产业和调整财政支出政策;安徽省应加强了财政收入对其区域经济的贡献作用。     

Geographic analysis of road accident severity index in Nigeria

Before 2030, deaths from road traffic accidents (RTAs) will surpass cerebrovascular disease, tuberculosis, and HIV/AIDS. Yet, there is little knowledge on the geographic distribution of RTA severity in Nigeria. Accident Severity Index is the proportion of deaths that result from a road accident. This study analysed the geographic pattern of RTA severity based on the data retrieved from Federal Road Safety Corps (FRSC). The study predicted a two-year data from a historic road accident data using exponential smoothing technique. To determine spatial autocorrelation, global and local indicators of spatial association were implemented in a geographic information system. Results show significant clusters of high RTA severity among states in the northeast and the northwest of Nigeria. Hence, the findings are discussed from two perspectives: Road traffic law compliance and poor emergency response. Conclusion, the severity of RTA is high in the northern states of Nigeria, hence, RTA remains a public health concern.     

华北地区休闲型农业园区空间分布特征及影响因素分析

［目的］近几年，华北地区休闲农业发展取得长足进展，研究其空间基本分布特征，剖析其发展影响因素，对把握其休闲农业分布现状，找准发展华北地区休闲农业关键入手点具有重要意义。［方法］以2012—2017年华北地区评定的680个休闲农业园区（企业）为样本，采用地理信息系统（GIS）对休闲型农业园区的空间分布特征进行简要分析，并利用层次分析法（AHP）探究华北地区休闲型农业发展的影响因素。［结果］（1）华北地区休闲型农业园区呈集聚分布，且集中分布程度极高，空间分布不均衡，主要集中分布在北京，其次为天津、河北、山西，内蒙古分布最少； （2）影响华北地区休闲型农业发展排名前3位的因素是公路密度、农林牧渔业总产值、城镇居民可支配收入； （3）目前城镇居民生活水平显著提高，游客消费水准已成为影响休闲型农业产业发展的重要要因素但并非决定性因子。［结论］休闲型农业是一个新产业，影响华北地区休闲农业发展的重要因素还是政府以及投资者，游客的可意愿度、经济能力已经不是休闲型农业产业发展的决定性因素。要发展休闲农业产业要从增加对投资者的政策导向以及增加园区（企业）的可到达性，将公路密度适当向郊区拓展入手。     

航班流时空分布不均衡程度评价方法

为了量化航班流在空域内时空分布的不均衡程度,通过将广义的均衡性评价工具泰尔指数和基尼系数应用在民航领域的方法研究量化航班流分布的不均衡程度的方法.定义泰尔空间分布不均衡度、基尼空间分布不均衡度、泰尔时间分布不均衡度和基尼时间分布不均衡度4个指标,通过这4个指标来评价航班流的空间分布不均衡程度和时间分布不均衡程度.以国内某飞行情报区为例,计算空域内每个时间片段的泰尔空间分布不均衡度和基尼空间分布不均衡度,计算这两个指标的相关系数为0.9734,结果表明两个指标具有极高相关,判断两种方法得出的评价结果是一致的,并且评价结果与实际情况相符.计算该飞行情报区内每个扇区的泰尔时间分布不均衡度和基尼时间分布不均衡度,得到这两个指标的相关系数为0.8101,结果表明这两个指标高度相关,且两种方法的评价结果与实际情况相符.研究证明可以利用基尼系数和泰尔指数来评价航班流时空分布的不均衡程度.