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1.
论文借鉴欧洲控制研究中心以机型为基本单元的延误成本估算模型(简称EC估算模型)及其相关算法,以EC估算模型为基础,补充机型配置比和引入航班执行阶段作为影响参数,估算了24 h中国枢纽机场单位时长延误成本和时间延误总成本,进行了时间延误成本的航线影响分析及中美比较,得到如下结论:① 区域枢纽机场时间延误成本普遍低于复合枢纽机场,但前者中机型单位时长延误成本和登机口成本均高于后者,从中可透视出其分别与中国航线网络中心集聚、航空地理市场(机型配置)需求和航线网络模式应用的密切相关;枢纽机场空中维持成本在时间延误总成本中占比最大,说明中国空中廊道设置存在缺陷。② 枢纽机场间(航线)以及枢纽机场与非枢纽机场之间(航线)时间延误总成本的差异深受航线属性所影响,其根本又在于航空地理市场(机型配置)需求以及空中廊道参与机场位置。③ 中美枢纽机场和枢纽机场间(航线)时间延误成本均有较大差异,主要表现为中国空中维持成本远高于美国,这是由空中廊道特征路径宽度和航迹交叉点数量2个因素造成的。  相似文献   

2.
Singapore is the third largest oil-refining centre in the world, with a large petrochemical hub located at Jurong Island. In view of the increasing concern for transportation security, there is an urgent need to improve the way trucks carrying hazardous materials (HAZMATs) are being routed on urban and suburban road networks. Routing of such vehicles should not only ensure the safety of travelers in the network but also consider the risk of the HAZMAT being used as weapon of mass destruction. This paper explores a novel approach to evaluating the risk of HAZMAT transportation by integrating Geographic Information Systems (GISs) and Genetic Algorithms (GAs). A set of evaluation criteria that are used to route the HAZMAT vehicles was identified and assessed. The criteria considered are related to safety, costs and, more importantly, security. A GIS was employed to quantify the factors on each link in the network that contribute to the evaluation criteria for a possible route, while a GA was applied to efficiently determine the weights of the different factors in the hierarchical form, allowing for the computation of the relative total costs of the alternate routes. Therefore, each route can be quantified by a generalized cost function from which the suitability of the routes for HAZMAT transportation can be compared. The proposed route evaluation method was demonstrated on a typical portion of the road network in Singapore.  相似文献   

3.
王建坡  李钢  杜梦佳  王莺莺  胡敏  于悦 《热带地理》2022,42(9):1547-1558
文章聚焦于中国拐卖妇女儿童犯罪高发省份广西,整合公益平台“宝贝回家”数据、“中国裁判文书网”的拐卖犯罪案例,以及基于搜索引擎获取的历年新闻报道的重特大拐卖案件等多源数据资料,运用数理统计、案例分析、空间分析等方法,多维度探究广西拐卖妇女儿童犯罪的时空格局及形成机制。结果表明:1)犯罪人以男性为主,集中于20~55岁年龄段,受教育程度较低,团伙特征明显;被害人以男性婴幼儿为主,在年龄上表现出低龄高峰(婴幼儿)和大龄次峰(妇女)的“双峰”特征;收买人文化程度以初中及以下为主,职业以农民或无业居多。2)犯罪的年际变化整体呈现“沙丘”型变化趋势,分为低发期、高发期、中高位波动期和持续下降期4个阶段。3)市域尺度下,被拐未成年人数量与该市人口数量普遍呈正相关;拐卖路径上,拐出路径整体呈现“以桂为源,粤闽及华北为汇”的格局,拐入广西的路径以“周边邻近拐入和跨境中转拐入”为主,性别对拐卖路径分异影响较大,男童主要被拐入闽粤,区域相对集中,女童主要被拐入粤闽桂冀鲁,分散度较高。4)特殊的地理区位造就独特的社会经济文化环境,在各种推拉力的综合作用下,造成广西拐卖妇女儿童犯罪的发生与扩张,最终形成独特的广...  相似文献   

4.
Facilities connectivity is a priority area for implementing the Belt and Road Initiative (BRI). The “China-Europe Railway Express” (CER Express) mode of transport organization links China with Europe by fast-track cargo rail. A major instance of facilities connectivity related to this project is an important practical and symbolic instance of BRI transport cooperation. The strategic significance of the CER Express and a number of operational issues are outlined, as are the implications of limited market potential for costs and competitiveness. A “hub-and-spoke” organizational model that can generate scale economies and reduce costs is proposed. To examine the establishment of an organizational model of this kind, the economic hinterlands of Alashankou, Erenhot, and Manzhouli are identified under high-, mediumand low-cost scenarios using an analytical methodology that determines distance and economic costs, and a number of transport hubs (that include Harbin, Zhengzhou, and Lanzhou) are identified. The results found that the cost of the routes from 314 Chinese cities to Moscow is the lowest via Manzhouli in the high- and medium-cost scenarios, but the routes change via Erenhot in the low-cost scenario. A number of policy recommendations should follow up.  相似文献   

5.
To plan undeveloped optimal routes between Asia and Europe via the Arctic Northeast Passages using a 3D geographic information system (GIS), voyage paths are simulated in a 3D visual form. This ensures that the distances are calculated accurately, and that other voyage data such as water depths, sea ice distribution, and seashore topology are also easily deciphered, giving a more direct and clear demonstration compared to simplified presentations on an Electronic Chart Display & Information System (ECDIS). This article also implements a higher-geometry maze router in ice zone areas to obtain the optimal path in relation to safety and costs. This article compares the optimal Arctic Northeast Passages with traditional routes through the Suez Canal for dynamic analyses of the cost efficiency (including time costs, fuel costs, and other factors) of travel between major ports in Asia and Europe. The average benefit assessment is around 30–45% in a bulk carrier comparison. Thus, a 3D GIS can easily obtain and demonstrate safe navigation routes, providing a very convenient tool for initial planning.  相似文献   

6.
Facilities connectivity is a priority area for implementing the Belt and Road Initiative(BRI). The "China-Europe Railway Express"(CER Express) mode of transport organization links China with Europe by fast-track cargo rail. A major instance of facilities connectivity related to this project is an important practical and symbolic instance of BRI transport cooperation. The strategic significance of the CER Express and a number of operational issues are outlined, as are the implications of limited market potential for costs and competitiveness. A "hub-and-spoke" organizational model that can generate scale economies and reduce costs is proposed. To examine the establishment of an organizational model of this kind, the economic hinterlands of Alashankou, Erenhot, and Manzhouli are identified under high-, mediumand low-cost scenarios using an analytical methodology that determines distance and economic costs, and a number of transport hubs(that include Harbin, Zhengzhou, and Lanzhou) are identified. The results found that the cost of the routes from 314 Chinese cities to Moscow is the lowest via Manzhouli in the high-and medium-cost scenarios, but the routes change via Erenhot in the low-cost scenario. A number of policy recommendations should follow up.  相似文献   

7.
北极航道海运货流类型及其规模研究   总被引:1,自引:0,他引:1       下载免费PDF全文
张侠  寿建敏  周豪杰 《极地研究》2013,25(2):167-175
从北极海运货源角度出发,根据北极贸易、油气开发以及远东-西北欧、远东-北美东部当前海运货量状况,分析得出未来北极航道主要货物类型和规模的最大理论值为:(1)从俄罗斯、北欧北极地区到远东的液化天然气单向贸易流型式,到2030年,为1 000万t;(2)从远东到欧美的集装箱货物双向贸易流型式,北极东北航道、中央航道分担远东到西北欧航线的货运量,北极西北航道分担远东到北美东部的货运量,如果技术上能够低成本保障全季航行,按分担传统运河航线50%计算,到2030年,北极航道集装箱货运规模最大值约为1 743万TEU,是2011年传统运河航线的85%。由此得出结论:近中期东北航道天然气运输占据主要地位,但对北极航道更大运输需求是集装箱运输。此外,本文还比较了北极航道与运河航线的成本。  相似文献   

8.
The number of unauthorized tunnels discovered through the U.S.–Mexico border has risen dramatically since the mid‐1990s. These tunnels are problematic for the state because the subterranean border is both less visible and more difficult to monitor and control than is the surface border. In this era of heighten security, the debate on secure borders has intensified. As a result, the need to demonstrate security success at both the national and the agency level has risen. Efforts to make tunnel discoveries (and security) visible are made within border‐security agencies and within national discourse and legislation. These efforts spatially fix tunnels to the border in ways that obscure fuller a understanding of drug trafficking in general. This paper employs archival research, content analysis, and informal interviews with security‐enforcement agents to consider the material presence of tunnels within border landscapes.  相似文献   

9.
The increasing quantities of solid waste and the high costs of its collection call for modifications of the collection routes in urban areas, in order to reduce the number of collecting teams and the distances travelled by them. Several mathematical models, aiming at the optimization of route length, are examined in this paper. It is suggested that the solutions derived from these models are only partial and that they cannot fully handle some of the constraints which the collection routing problem involves. The preferred method, therefore, is the heuristic model which is based on manual analysis of the routes system using a set of specified rules. This method is, then, used for an analysis and modification of the waste collection routes of Givatayim, Israel. Implementation of the proposed routes may save the town one out of six collection teams and would reduce the total distance travelled by some 18.7 per cent.  相似文献   

10.
苏晓波  蔡晓梅  周灿 《热带地理》2019,39(6):799-811
与中国云南省接壤的缅甸北部少数民族自治邦,包括掸邦和克钦邦,构成全球第二大非法毒品生产地的金三角核心区。通过借助历史档案和学术文献,聚焦缅甸北部,基于政治地理的视角,理清缅甸北部毒品贸易的历史起源,探讨了自缅甸1948年独立后毒品贸易给该国带来的政治与经济危机,以及相应的地缘政治冲突和外部干预。文章试图回答的问题有:为什么毒品贸易能够在缅北扎根?毒品贸易如何影响缅甸政府在其北部山区的主权完整和领土控制?文章的核心观点是毒品成为缅甸国内破碎主权和外部势力干预的原因和结果,毒品贸易以及与毒品相关的犯罪活动已经渗入缅北,严重危害了缅甸的主权完整。毒品贸易也为外部势力介入缅甸国内事务提供了契机。由于主体民族缅族控制的中央政府同缅北的少数民族地方武装间缺乏足够的信任,民族和解缺乏基础,也无法为全面禁毒创造有利的政治条件。因而,缅北的毒品贸易和缅甸的国家建设相互影响,导致国家主权破碎化和外部干预,导致缅北成为亚洲最贫穷落后的地区。文章分析以毒品为核心的开源权力机制与非正式或者非法全球化,丰富了Agnew有关主权的理论,在实践方面有助于认识中缅边境安全的复杂性,促进云南同东南亚的跨国区域化。  相似文献   

11.
刘岩 《地理研究》1998,17(3):303-308
在区域产业经济发展过程中,地缘优势、经济规律、文化传统都是不容忽视的重要因素。文章以安国市的药材产业为研究实例,通过解释中心集聚的“空间拉力”所孕育的对外交流的潜力,揭示“交易成本机制”在市场交易中的刺激作用,以及分析安国药市网络管理的特定形式,对药材产业区域发展的地理、历史、经济和文化因子作了综合性研究。  相似文献   

12.
13.
This article uses the global production network perspective to analyze the various actors involved in the production and distribution of methamphetamine in North America. The paper analyzes the organization and operation of the two dominant network typologies at work in the United States: small toxic labs and Mexican drug‐trafficking organizations. Particular emphasis is placed on how the networks have adapted to changes in the regulatory context in which they operate. I conclude with potential policy recommendations for curtailing methamphetamine production within both networks.  相似文献   

14.
流域景观功能网络构建及应用——以台湾乌溪流域为例   总被引:3,自引:0,他引:3  
选择生态及城市功能并重的台湾乌溪流域,在乡镇行政单元的基础上,利用耗费距离模型将景观功能网络落实于实际的空间单元。透过网络节点间的通达性分析可知,乌溪流域的景观功能网络中以城市功能网络结构较佳,城市子节点多环绕于城市功能中心,功能的输出与传递有较高的效益;而生态功能网络节点间通达性差异并不显著,唯作为一级及二级功能节点的红香、高美湿地等位置孤立、通达性较差,需就其功能向外传输路径进行优化,并提升二载山及北坑子等重要联系节点的生态功能强度。  相似文献   

15.
岳佳霏  潘柳榕  宗会明 《热带地理》2022,42(7):1096-1106
选取南海周边国家和地区37个集装箱港口为研究对象,选用全球前八名船公司航线数据,就其现有航线分布构建二向网络,采用度数中心度、接近中心度、介数中心度及权利指数等复杂网络中心性指标和网络结构模型对其港口体系特征和网络结构进行研究,得出的结论主要有:1)近年来,南海沿线国家和地区间贸易愈加频繁,相关港口吞吐量不断增加,在世界集装箱港口体系内地位总体呈上升态势;各港吞吐量排名总体相对稳定,南海周边7国集装箱港口运力分布不均衡,主要集中在中国与新加坡沿线。2)深圳港、新加坡港、香港港、高雄港、青岛港与上海港等港航线较多,可与较多区域直接进行贸易往来,受其他港口联系影响较小;上海港、深圳港、宁波舟山港、广州港等在国际集装箱航线中起重要的串联中介作用,对航运网络控制能力较强。3)基于港口吞吐规模与中心程度分异情况将港口网络地位分为4层。第一层为国际航线母港,包括上海港、新加坡港、深圳港、宁波舟山港、广州港、青岛港与香港港;第二层为国际航线枢纽港,包括高雄港、丹戎帕拉帕斯港、厦门港、天津港、林查班港、巴生港与胡志明港,中心性发育程度较好;第三层为国际航线挂靠港,包括海防港、钦州港、大连港、丹绒布鲁港、马尼拉港、丹戎佩拉港、连云港、盖梅港、烟台港、营口港、日照港与福州港,港口相对中心度偏低,吞吐量相对受限;第四层为区域性喂给港,包括锦州港、太仓港、台中港、东莞港、唐山港、南京港、泉州港、南通港、珠海港、嘉兴港与海口港,因其地理区位特点成为较热门转运港口。4)整体港口网络可划分为4个港口社群。其中,社群一中心属性明显,社群二与其联通关系紧密,社群三是其喂给港群,社群四小世界属性明显,群内港口航线相对独立。  相似文献   

16.
For nomadic pastoralists in arid environments, judicious migration of the herds is the principle strategy for short term survival and long term sustainability. Yet, this efficient mechanism is increasingly challenged by mounting population pressure, appropriation of land and restricted transboundary movements. Lack of information on trekking patterns and grazing areas makes it difficult for government authorities to protect the migration routes. Data are so scarce because the object of measurement is moving in directions no outsider can predict. Consequently, data collection is costly and laborious. The present study suggests the use of satellite telemetry to trace trekking routes in a near real-time mode that can operate without the presence of external observers on the ground. We report on a pilot that tests a remote tracking technique to locate the routing of a nomadic pastoralist during the dry spell, in the Afar region of Ethiopia. From a movement analysis we infer trekking routes and grazing areas as well as the spatial and temporal correlation between the vegetation cover index NDVI, and the visits by the herd. Our first results seem encouraging in that our data collection method can produce unique information relatively quickly and at low cost.  相似文献   

17.
This paper reports on log transportation as a health-related issue in the Hokianga district of Northland at a time when forestry activity in the area is expanding and radical reforms to New Zealand's roading network have been proposed. Drawing on technical information and key informant interviews, the potential impacts of logging trucks on Hokianga roads are considered, the costs associated with forestry traffic are estimated, and the routes most likely to be affected are identified. Possible responses to the log transport problem are discussed, and it is concluded that rural communities such as Hokianga are vulnerable to both logging truck activity and changes in government policy.  相似文献   

18.
A new raster‐based GIS model that combines multi‐criteria evaluation and least‐cost path analysis was developed to determine the optimal haulage routes of dump trucks in large scale open‐pit mines. The model logic can consider multiple criteria simultaneously (i.e. speed, water body, ore body, curve, visibility, haul road maintenance) and can rate the adverse factor scores of truck movement using fuzzy membership functions. After establishing the weights of five factors by pairwise comparisons, the average adverse score grid can be generated by the weighted linear combination of factor and constraint scores. New software, called Dump Traveler, was implemented to improve the availability of the developed model. An application to the Roto South pit in the Pasir open‐pit coal mine, Indonesia, showed that the software can provide rational solutions to determine the optimal routes on truck haulage operations. Moreover, the layout of available haul roads can be evaluated to consider the trade‐off between road maintenance costs and the potential for traffic jams. Variations of weights for factors were found to be sensitive to the optimal haulage routes determined by least‐cost path analysis. The software provides both optimal routes on truck haulage operations and approximately estimated travel times along the routes, therefore it can support other truck dispatching software that mainly considers scheduling problems.  相似文献   

19.
新冠疫情对中国国际航空网络连通性的影响及空间差异   总被引:1,自引:0,他引:1  
杜方叶  王姣娥  王涵 《热带地理》2020,40(3):386-395
航空运输在实现各国互联互通、推动全球经济发展中发挥着重要作用。突发公共卫生事件或恶劣天气等均易对航空网络的连通性造成影响。本研究以新冠疫情为例,从全球航空网络视角探讨新冠疫情对中国国际航空网络连通性的影响及地区差异。研究结果表明:疫情期间,中国境外通航城市、国际航班、国际航线数量均大幅缩减,航空网络连通效率显著降低,但其空间格局未发生根本性变化,东亚和东南亚仍是中国对外主要联系地区,经济联系与贸易仍然起着重要作用。航线停飞对中国与中亚、西亚和大洋洲航空网络的连通性影响最大,而航班缩减对中国与东亚、中亚和东南亚航空网络的连通性影响最大。在国内,北京、上海和广州仍然是中国对外联系的枢纽城市,且其聚集度在疫情期间得到提升。  相似文献   

20.
厦门城市自助游网络结构及机制研究   总被引:1,自引:1,他引:0  
从省外自助游客发表在携程网上的厦门游记中提取旅游流信息,运用社会网络分析和QAP相关分析对城市自助游网络结构特征及形成机制进行研究。结果表明:在时间、经济等多重制约因素的影响下,厦门旅游节点呈现高度的不均衡性,处于核心区域的7个节点间彼此联系密切,且节点间的距离较近,形成高度集聚效应,对省外自助游客形成了“刚性”吸引力,其他边缘区旅游产品是第二选择;边缘区节点“抱团”现象也很普遍,无论是节点较为密集的环岛路还是岛外的节点群,说明即便在交通体系已经很发达的厦门,距离摩擦对于游客游览路线的选择均起到一定影响;QAP相关分析得出旅游流的形成与距离对外交通设施和酒店的远近相关性不显著,与节点的公共交通通达性、网络知名度及节点的集聚程度有显著的相关性;针对岛内外节点应采取不同的策略来降低时间和经济成本,提高核心节点游览效率,完善预警机制,同时挖掘岛内外旅游产品的互补性,从而实现旅游空间的相对均衡。  相似文献   

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