进路搜索的数据结构与算法及其仿真

对铁路车站计算机联锁中的进路搜索,提出基于站场数据结构的进路自动生成搜索算法。在确定对象节点数据结构的基础上,给出了进路搜索算法的步骤。同时将站场设计功能也包含在程序中,进而可以虚拟出各种不同的站场,根据实验选择不同的进路始点和终点,可达到良好的仿真效果。     

九寨——黄龙核心景区生态旅游环境保护探析

本文基于对九寨—黄龙核心景区生态保护现状的分析,对景区生态环境保护进行了诊断,并提出应以环境容量为基础,运用经济原理,整合行政资源,以达到管理科学、生态平衡、持续发展的目标。     

福建省粮食物流网络建设的构想

根据福建省各地区不同特点,充分利用资源优势,建设粮食物流网络。将现代科学技术和管理方法应用到粮食物流节点布局和线路优化中,使粮食物流沿着合理流向,用最少的费用实现从产区向销区的移动,避免对流、倒流、迂回等不合理运输,形成完整的覆盖不同地区、纵横相联、高效低耗的粮食物流网络体系,从而降低粮食物流成本。     

西方空间集聚—扩散理论及北京城区功能的扩散

已被世界上许多国家区域经济发展实践验证的西方空间集聚一扩散理论，是对区域经济发展中带有普遍性特征规律的理论表述。以这一理论为基础，结合北京城区集聚不经济的实际，加快北京城区工业企业、事业单位和与此相伴的住宅、商业用房、交通枢纽、第三产业的择情扩散，保证有效扩散的法律、税制、规划、政府职能、中小城镇、乡镇企业的发展和网络建设等相关环境的建设步伐，是促使北京作为国家首都、世界城市、文化名城、宜居城市功能有效发挥和提升京津冀区域经济合作等级的重要步骤。     

一种基于佳点集遗传算法的物流配送网络优化

首先根据实际问题分析了物流配送网络优化模型的各个关键组成部分,包括优化目标、决策变量和约束条件,并针对目前物流配送网络优化算法中存在的一些问题提出了一种新的算法,其核心是佳点集遗传算法。该算法编码采用prufer num ber结构,变异和交叉概率自适应选择。     

Competition with Congestible Networks

We analyse competition between two network providers when the quality of each network depends negatively on the number of customers connected to that network. With respect to price competition we provide a sufficient condition for the existence of a unique pure strategy Nash equilibrium. Comparative statics show that as the congestion effect gets stronger quantities will decrease and prices increase, under both Bertrand and Cournot competition. In an example with endogenous capacities it turns out that equilibrium capacities are at first increasing and then decreasing in the strength of congestion. Furthermore, capacities are higher under Cournot competition. Welfare comparisons between Bertrand and Cournot competition are unambiguous for fixed capacities, but may turn around for endogenous capacities.     

武陵山片区旅游节点交通畅达性研究

区域旅游节点的交通畅达性对区域经济发展具有强劲的推动作用,区域旅游节点的交通畅达性优劣取决于内部的连通性和外部的可达性。文章基于因子分析法分别就高等级公路、高速公路、普铁、高铁(动车)、民航航线等因素对武陵山片区内各旅游节点的交通畅达性的影响进行了评价分析,对各旅游节点的畅达性进行了排名;并选取2010、2014、2018年等3个时间节点数据导入GIS生成3个片区旅游交通图。研究发现:①重庆、武汉、长沙、贵阳四大中心城市的交通连线支撑起武陵山片区的交通网络,片区旅游节点之间的畅达性逐步提升;②处于武陵山片区外围重庆、武汉、长沙、贵阳四大中心城市交通大廊道上的旅游节点之间畅达性处于片区前列;③同一省市或同一传统旅游线路的旅游节点连通性较好,分属不同省市的旅游节点之间连通性普遍较差;④历史上,山高谷深、交通闭塞,各地市自然旅游资源丰富多样,文化旅游浓郁独特,近年来,武陵山片区旅游发展与交通建设相互推拉,呈现良性发展。     

TCP/IP拥塞控制研究

综述了Internet上TCP/IP拥塞控制研究方面一些最新的工作,分析了拥塞控制的原理、TCP/IP拥塞控制所使用的典型技术,并着重论述了TCP/IP拥塞控制所面临的问题,包括自相似性问题、效率问题、区分服务等问题,并提出进一步研究的方向。     

Two-settlement Systems for Electricity Markets under Network Uncertainty and Market Power

We analyze welfare and distributional properties of a two-settlement system consisting of a spot market over a two-node network and a single energy forward contract. We formulate and analyze several models which simulate joint dispatch of energy and transmission resources coordinated by a system operator. The spot market is subject to network uncertainty, which we model as a random capacity derating of an important transmission line. Using a duopoly model, we show that even for small probabilities of congestion (derating), forward trading may be substantially reduced, and the market power mitigating effect of forward markets (as shown in Allaz and Vila 1993) may be nullified to a great extent. There is a spot transmission charge reflecting transportation costs from location of generation to a designated hub whose price is the underlying for the forward contract. This alleviates some of the incentive problems associated with the forward market in which spot-market trading is residual. We find that the reduction in forward trading is due to the segregation of the markets in the constrained state, and the absence of natural incentives for generators to commit to more aggressive behavior in the spot market (the strategic substitutes effect). In our analysis, we find that the standard assumption of no-arbitrage across forward and spot markets leads to very little contract coverage, even for the case with no congestion. We present an alternative view of the market where limited intertemporal arbitrage enables temporal price discrimination by competing duopolists. In this framework, we assume that all of the demand shows up in the forward market (or that the market is cleared against an accurate forecast of the demand), and the forward price is determined using a market clearing condition.     

试论某高层建筑逆作法施工技术

当前随着我国城市发展进程的逐步加快,城市居住空间越来越小,为缓解城市土地紧张局面,高层建筑应运而生。随着我国建筑施工技术水平的不断提升,逆作法作为一种新型施工方法,极大地提升了施工效率和质量,保证了居民的生命财产安全,受到了施工单位的一致欢迎。本文主要就高层建筑逆作法施工技术进行了研究。