中国空中廊道划设与时空拥堵识别及其航线流量影响   总被引：3，自引：0，他引：3  

董雅晴  路紫  刘媛  张秋娈 《地理学报》2018,73(10):2001-2013

航空运输的迅速发展使空中交通流增加,空中廊道因能容纳高密度交通流而成为支持空域资源充分开发利用的一种新技术,空中廊道拥堵时段和拥堵区段的识别是廊道上车道分配和开合操作的基础。在回顾空中廊道与交通拥堵相关研究后,构建了由空中廊道划设、拥堵状态识别、航线流量影响组成的研究方法。依据高流量航线确定空中廊道位置、依据距离约束条件确定航线参与者,合并划设出全国14条空中廊道;进而通过时空数据计算、时空图编绘、网格频数筛选及划分阈值设定等步骤,遵照重叠次数及热格频数的指示规则,对拥堵时段和拥堵区段进行识别;并通过规模值和汇聚值两个指标分析高流量航线的拥堵影响。研究发现：拥堵时段呈现为全天多峰“波浪型”分散分布及高峰后端集聚的结构特征;拥堵区段整体呈现为不平衡覆盖和交汇节点集中分布的结构特征,其中高拥堵程度的空中廊道呈现为一个斜体“N”字型框架,框架上为小区段集中的不完全贯通;时空交互上,拥堵区段存在单一时段和多时段重叠两种类型,多个廊道的不同拥堵区段存有共同拥堵时段。高流量航线在空中廊道拥堵中起相对决定性作用,且在抵港和离港两个方向上的影响不均衡。空中交通拥堵识别可为中国未来空域资源时空动态评估和空中廊道建设提供依据。  相似文献   

Perception of pleasure in the urban running environment with street view images and running routes     

ZHANG An  SONG Liuyi  ZHANG Fan 《地理学报(英文版)》2022,32(12):2624-2640

The urban environment affects human behavior and health. Most studies on the feelings of street spaces have not considered a specific kind of realistic scene, such as running. To overcome this limitation, we explored the relationship between the urban environment and the pleasure of running. We collected 8260 street view images from 153 running routes in Beijing and invited more than 400 volunteers of different genders and ages to rate their sense of pleasure in street view images of the urban running environment through an online survey. Then, the proportion of visual elements in street images was extracted based on semantic segmentation, and the landscape was divided. Finally, a linear mixed model was used to predict the pleasure scores of different gender and age groups for different landscapes. The results show significant differences in the pleasure scores for different landscapes and age groups. Middle-aged people's sense of pleasure was lower than that of the young and the elderly. More greenery was associated with a higher pleasure score, while the proportion of urban elements such as buildings was negatively correlated with the pleasure score. The results indicate that running in a natural landscape is pleasurable and beneficial for mental health.  相似文献   

Developing self-guided scuba dive routes in the Algarve (Portugal) and analysing visitors' perceptions     

《Marine Policy》2014

Scuba diving allows for underwater visitation of cultural and natural resources. Underwater routes can be used as a tool for guided and supervised underwater visits. Two scuba diving routes were implemented in the Algarve (South of Portugal), the “B24” and “Poço” diving sites. The perceptions of scuba divers regarding several aspects of the routes and the existing support infrastructures were studied following a survey carried out through face-to-face interviews from 2008 to 2012. Divers profile and their perceptions were analysed using 246 valid questionnaires. Divers were mainly Portuguese, over 30 years old and with more than 12 years of formal education. Some of the support infrastructures did not achieve a “good” or “acceptable” grade. This should be carefully considered by diving operators and managers, because perceptions tend to circulate throughout the diving tourists. All features of interpretative slates were graded as highly satisfactory. Overall, diver satisfaction increased slightly after route implementation, with an average ranking of “good”. These findings support the implementation of underwater routes as a way to promote diving activity, and to increase divers' environmental education and awareness.  相似文献   

Have a nice trip: an algorithm for identifying excess routes under satisfaction constraints     

H. Skov-Petersen  M. Zachariasen  P.K. Kefaloukos 《International journal of geographical information science》2013,27(11):1745-1758

Analysis of potential spatial behavior in transport infrastructures is usually carried out by means of a digital network. A basic condition for such a network analysis has traditionally been the desire to find solutions to optimization problems and to achieve greater efficiency in industry. Geographic information system (GIS) tools for network analysis are overwhelmingly targeted at finding solutions to optimization problems, which include the shortest path problem and the traveling salesman problem. This article addresses the problem of the lack of tools for finding solutions to a class of constraint satisfaction problems that are of potential interest to behavioral geographers. Constraint satisfaction problems differ from optimization problems in that they lack an expression to be maximized or minimized. We describe how a constraint-based approach to network analysis can be applied to search for ‘excess routes’ that are longer or in other ways exceed single, optimal routes. Our analysis considers both round-trips and travel from A to B and defines a set of constraints that can characterize such paths. We present a labeling algorithm that can generate solutions to such excess route problems.  相似文献   

京杭大运河的完全价值观   总被引：4，自引：0，他引：4  

俞孔坚  李迪华  李伟 《地理科学进展》2008,27(2):1-9

从理论和现实背景出发, 提出对京杭大运河价值的初步认识: 京杭大运河具有四大基本价值: (1) 作为文化 遗产的价值, 起到彰显民族身份和促进文化认同的作用; (2) 作为区域城乡生产与生活的重要保障, 具有输水、航运 和灌溉等现实功能的价值; (3) 作为区域生态基础设施的价值, 是保障国土生态安全的关键性格局; (4) 运河还具有 作为潜在的休闲通道的价值, 是国民身心再生和教育的战略性资源。强调只有用完全的价值观充分认识运河廊道, 并处理好现实的功能需要与这些价值间的相互关系, 才能保护和利用好运河遗产及其相关资源, 使之在当代发挥 应有的作用。在此基础上提出以建设遗产廊道的方式、结合南水北调和东部生态安全格局及中国南北生态休闲廊 道的建设, 将保护与利用京杭大运河作为国家战略。当务之急是: (1) 应用“反规划”理念进行运河的整体保护规划; (2) 展开资源摸底, 全面掌握大运河遗产廊道资源情况; (3) 制定整体性的管理和发展战略; (4) 以申报世界遗产南 水北调工程为契机, 建立大运河区域间协作机制。任何单一的价值观(如从单一的输水功能考虑) 和单一的工程措 施, 都将给中国大地上这一独特的文化景观和与之相联系的历史文化、生态及社会经济系统带来不可挽回的遗憾。  相似文献   

万年闸船闸浮式系船柱槽的施工     

张玉强  朱平 《海岸工程》2004,23(3):52-60

浮式系船柱槽是万年闸船闸的重要组成部分。介绍了浮式系船柱槽的详细施工方案和质量保证措施。  相似文献   

洪灾应急疏散路径规划算法优化     

李梦雅  王军  沈航 《地球信息科学学报》2016,18(3):362-368

应急疏散是救灾工作的重要环节,合理的路径规划能有效缩短疏散时间,减少人员伤亡.本文以疏散总时间最短为目标,考虑需求控制,容量限制,交通延误,公平分配和资源节约等约束条件,对经典Dijkstra算法进行改进;并采用混合拆分疏散方法,构建洪灾避难应急疏散路径规划模型.运用C#语言编写算法,求解最佳路径,基于自主开发的应急疏散分析工具MiniGIS,对规划路径进行动态模拟,依据反馈逐次优化算法.结果表明:理想算法,延时-改进算法,逆行-改进算法均能为县域尺度的洪灾避难疏散路径选择提供参考,但理想算法适用于组织简单,高度有序的疏散情景,延时-改进算法考虑了除交通拥堵之外的延误,与真实情况更为接近,逆行-改进算法避免了因中途路径调整而出现的"回头路",在时间最短次优的条件下,更有利于疏散过程管理与资源节约,其结果被认为是此次应急疏散路径规划的最优解.  相似文献   

南阳膨胀土渠道滑坡破坏特征与演化机制研究   总被引：3，自引：0，他引：3  

陆定杰  陈善雄  罗红明  戴张俊  李扬帆  陈平 《岩土力学》2014,35(1):189-196

为了解河南南阳地区膨胀土渠道边坡滑坡机制,基于南水北调中线工程南阳段19个滑坡的现场调研统计结果,选取南阳段TS105+400处右岸滑坡为典型实例,开挖探槽揭露滑坡内部结构,对该区膨胀土渠道滑坡的破坏特征及演化机制进行了研究。结果显示,该区滑坡多发生在 地层;边坡的稳定性受中上部土体中的垂直节理及坡脚充填强膨胀土的缓倾长大裂隙共同控制,滑动面由后缘陡倾裂隙及前缘缓倾长大裂隙组成。开挖卸荷导致垂直节理张开,垂直节理向下可延伸3 m以上,破坏边坡土体整体性,且充当水分出入边坡的主要通道;坡面以下深度4～8 m存在一个高湿度带,带内土体强度小,发育滑动面。气候造成的胀缩循环、开挖卸荷导致边坡垂直节理张开并向深部发展,对边坡土体的强度衰减作用明显,当垂直裂隙与前缘缓倾裂隙贯通后,发生强（久）降雨,裂隙充水软化,即诱发边坡失稳。  相似文献   

我国沙尘的来源、移动路径及对东部海域的影响   总被引：13，自引：0，他引：13  

张凯  高会旺  张仁健  朱燕君  王跃思 《地球科学进展》2005,20(6):627-636

利用中国气象局提供的micaps天气资料,通过对2000—2002年发生的42次沙尘天气个例的分析,重点研究了沙尘的源地、移动路径、入海地点及对不同海域的影响概率。结果表明：影响我国的沙尘天气有70%起源于蒙古国,在经过境内沙漠地区时得以加强。沙尘粒子的移动和入海途径主要有3条：一是从内蒙古东部入侵的沙尘天气经浑善达克和科尔沁沙地后进入渤海和黄海;二是从内蒙古西部入侵的沙尘天气经内蒙古西部沙地和黄土高原后进入渤海、黄海和东海;三是从青海东部扬起的沙尘长距离输运进入黄海、东海及西北太平洋。2000—2002年,63.9％的沙尘天气会影响到海洋,其中,影响渤海、黄海和东海的概率分别为27.4％、30.9％和12.3％,影响朝鲜海峡和日本海的概率为20.2％和9.2％。  相似文献   

长春市各级交通路线对城市功能用地变化的作用效应关系研究   总被引：1，自引：0，他引：1  

马佐澎  李诚固  张婧  申庆喜  周国磊  冯铁宇 《地理研究》2016,35(9):1687-1700

利用长春市中心城区2003年、2013年土地利用现状图,运用廊道效应原理与ArcGIS空间分析功能,揭示了交通系统“快速化”背景下长春市各级交通路线对城市功能用地演替的作用效应关系。研究发现：轻轨、主干路、快速路对商服用地的吸聚效应依次增强,快速路沿线商服用地主要用于专业化市场建设,轻轨沿线商服用地用作综合性商场开发;快速路对沿线居住用地吸聚强度大于主干路,轻轨对沿线居住用地具有近距离排斥效应;在市中心区,快速路、主干路、轻轨对工业用地的排斥强度依次增强,但随着由中心至外围的过渡,快速路的排斥效应将转化为吸聚效应。各级交通路线对沿线城市功能用地作用效应的差异性,一定程度上推动了长春市城市地域结构的演变。  相似文献