银川市冬季旅游开发及对策初探

冬季旅游开发相对滞后,缺乏深入而具体的研究工作曾是银川市旅游经济发展面临的严重缺憾.近几年,随着人们对冬季旅游的关注日益升温,银川市冬季旅游在尝试性发展的基础上也逐渐走上轨道.采取什么战略迎接机遇与挑战是银川市冬季旅游开发面临的首要问题.本文从银川市旅游经济的大背景出发,分析了银川市发展冬季旅游的优势、开发现状、影响冬季游资源开发的诸多因子.继而,依据一定的原则,提出了银川市冬季旅游在以冰雪为"底鬃座",文化为"火焰"的"火炬"式产品开发策略下提出具体的对策.     

A new source number estimation method based on the beam eigenvalue

Most source number estimation methods based on the eigenvalues are decomposed by covariance matrix in MUSIC algorithm. To develop the source number estimation method which has lower signal to noise ratio and is suitable to both correlated and uncorrelated impinging signals, a new source number estimation method called beam eigenvalue method (BEM) is proposed in this paper. Through analyzing the space power spectrum and the correlation of the line array, the covariance matrix is constructed in a new way, which is decided by the line array shape when the signal frequency is given. Both of the theory analysis and the simulation results show that the BEM method can estimate the source number for correlated signals and can be more effective at lower signal to noise ratios than the normal source number estimation methods.     

Effect of advanced traveler information systems and road pricing in a network with non-recurrent congestion

The effect of the application of advanced transport information system (ATIS) and road pricing is studied in a transportation system under non-recurrent congestion. A stochastic network deterministic user equilibrium model (SNDUE) with elastic demand is formulated and used to evaluate the welfare and private impacts of different market penetrations of ATIS, together with road pricing for a simple network. Both marginal first-best road pricing and a second-best fixed road pricing are considered. The incentives of private users to use ATIS are analyzed and the characteristics of optimum tolls as a function of ATIS market penetration are shown. We conclude that ATIS is an efficient and necessary tool to reduce the effects of non-recurrent incidents in a transportation network, especially when non-recurrent congestion causes a significant deterioration of operational conditions of the network. If the impact of non-recurrent incidents on free flow costs is small or is reduced only to congestion effects, the use of road pricing would be more efficient. Social benefits obtained when jointly implementing ATIS and road pricing are practically the same whether first-best or second-best road pricing is used. Considering the private costs perceived by the network users, and the benefits experienced by equipped users, the maximum level of market penetration achieved could be limited because private benefits disappear after certain market penetration is obtained.     

搅拌筒圆柱段叶片下滑角的计算分析

搅拌筒叶片的设计关系到搅拌车的搅拌性能。从理论上对搅拌筒转过不同的转角时圆柱段下滑角的变化规律进行了定量分析与计算。     

基于WEBGIS的管理维护系统

随着数字城市的普及，各种服务平台的开发已成为WEBOIS系统开发的一大热点。目前，更多的是关于WEBGIS系统的建设，对于系统的维护则很少提及。基于WEBOIS的管理维护系统主要针对各种WEBGIS服务平台系统开发研制，主要目的是对用户的信息访问权限和WEBGIS系统中所需数据和文件进行管理，它们是各种WEBGIS系统后台管理人员在应用系统当中不可缺少的模块。     

不同比例尺数字地形图的转换与拼接

阐述不同比例尺数字地形图转换、拼接的实现原理，分类研究不同比例尺地物、地貌符号的变换规律。对传统的地形图拼接观念提出质疑，并提出了新的见解。以Cass系统为例，介绍不同比例尺数字地形图的转换与拼接方法。     

Characterizing European high speed train stations using intermodal time and entropy metrics

This paper presents a quantitative method for characterizing high speed train stations in terms of passenger intermodality. The aim of the procedure is two-fold: firstly, the method is to be used as an objective measure for comparing stations in order to detect suboptimal points and improve the performance of stations as nodal points; secondly, the method provides a means to embed intermodality into regional accessibility models, allowing comprehensive modelling at lower scales. The empirical base of the work comprises data from 27 European high speed rail stations, which is deemed an appropriate statistical sample for the whole European rail network. Using the entropy metric, we found that several different patterns emerged: there was a clear hierarchy of stations which was linked to their respective roles within the system, while strong constraints impeded stations from performing optimally as true intermodal nodes.