Mode Choice in a Hub-and-Spoke Network: A Zero-One Linear Programming Approach

While research has tackled the hub-and-spoke network design problem, that research has overlooked the air-truck modal integration issue which is a common feature of real express delivery systems. This paper devises integer linear programs to represent the mode and route assignment aspects of the operational problem. The model is solved under four different levels of delivery schedule, and the results show that as the promised delivery schedule is relaxed, not only does the use of truck routes become more desirable, but also interesting adjustments in mode and hub assignment occur. Consider the case of hubs in Los Angeles and Dayton. As the time constraints are relaxed, cities such as Minneapolis and New Orleans originally linked by air to Los Angeles, switch to Dayton because cheaper truck routes become feasible.     

修昔底德选用史料方法刍议

修昔底德的史著以叙述伯罗奔尼撒战争为主要内容,涉及希腊世界主要城邦的政治、军事、经济、外交以及海陆交通等方面丰富多样的史料。修昔底德按照自己处理史料的原则,对于战前史和战争史本身的史料分别采取了不同的处理方法。对于战前史料的选择和考信方法主要采用比较考异法和反溯法;对于当代史料的选用及考信方法主要采取实录法、辨异法、推测法、纠错法、隐微法等五种。修昔底德貌似如实直书的表象背后,隐含着名副其实的“修昔底德陷阱”。     

普鲁士改革时期的浪漫主义:思想与行动

浪漫主义运动发生于18世纪末至19世纪30年代,是一场构建民族精神特质的思想塑造运动。柏林的宗教氛围、普鲁士君主制传统,特别是作为其“血脉”的等级制度在法国革命冲击后依然完好无损地保留,使浪漫主义者得以将普鲁士作为政治实验场开展活动。亚当·米勒和斯泰因是两位改革时期的浪漫派代表,一个从观念出发,将君主制、等级制“浪漫化”,用于指导改革;而另一个则从历史经验出发,在实践中尝试将君主制和等级制做出顺应时代的改变。他们的思想和实践对普鲁士的改革进程产生了重要影响。     

"承上制下"与"从左转右":北宋物资转输区域的互动——以东南地区为中心

北宋时期,朝廷在淮南地区运河沿岸州军设置转般仓,这些州军具有了转般粮食物资进京的功能;又先后置发运司于真州和泗州,使其开始具有总管东南漕运事务的职能;盐利也集中于此,同时亦掌控着地方物资的上供经费.其他物资转输区域则经常出现改变转运方式的情形,中转区域改变了起始区域输出物资的运输方式,减轻了部分运输成本.起始区域在加重中转区域负担的同时,亦对中转区域的经济繁荣有促进作用.     

Micro-CT-assisted determination of the shattering and non-shattering phenotypes of charred rice spikelet bases from archaeological sites: a new methodological approach

The selection of a non-shattering phenotype is a pivotal change in the process of rice domestication. However, current research is heavily restricted by the preservation conditions of macro-plant remains in early and middle Neolithic sites, as very limited well-preserved rice spikelet bases could be retrieved. We present a non-destructive method based on micro-computed tomographic (CT) scanning, which could provide detailed visualization of the internal structures of charred spikelet bases and efficiently discriminate the shattering and non-shattering phenotypes of rice spikelet bases according to the abundance of fusiform echinate phytoliths. It could be widely applied in different contexts, especially those poorly preserved specimens and tempers in pottery sherds, greatly improving our knowledge of rice domestication.     

AN ARTISTIC LIFE CREATED BY A PAIR OF SKILLFUL HANDS

正The cold season isjust about to arrive in Lhasa.A tallllbetan man is standing upon the golden roof of the Jokhang Temple to look out into distance.His name is Tsegya,a man with a deep affection for this very roof.This is the place where his karma connects him to his produced mandalas.Tsegya told me that     

基于GIS的沈阳旧城区叙事空间研究

20世纪60年代,叙事学作为一门学科始于西方历史学、文学领域。直至20世纪末,叙事学开始转向空间领域研究形成空间叙事学,并被逐步应用到城乡规划中,尤其是城乡空间结构等领域。空间叙事学不仅关注城市发展中的物化要素,更加注重物化要素所代表的城市文化和城市记忆等非物化要素的深入挖掘,是探究场所本体与场所精神的重要研究思路。本文从空间叙事学出发,基于GIS平台运用核密度及K函数对古代、近代、现代三个时期沈阳旧城区人工叙事要素和人文事件叙事要素进行点模式量化分析,得出沈阳旧城区叙事空间的总体结构,以及叙事点核、叙事廊道、叙事簇群等叙事空间结构单元,指出沈阳旧城区叙事空间的动态发展性、功能多样性和历史传承性特点,探讨了叙事空间的经济驱动、自然要素、城市定位和交通发展四大演变机制。从人文地理学的视角出发,结合叙事空间理论对沈阳旧城区叙事空间进行分析,结果具有文化地理和城市地理双重属性,丰富了城市研究在该视角下的研究成果。     

巴马盘阳河流域季节性移民社区类型与形成机理

季节性移民聚居现象受到西方学术界的极大关注,而我国鲜有研究。采用观察法和访谈法,对巴马盘阳河流域"一地多类"的季节性移民社区的形成过程、类型特征与作用机理进行归纳与揭示。研究表明：①季节性移民社区演变历经萌芽、快速参与和转型发展三个阶段,社区人口结构、聚居空间、经济业态、景观设施及人文氛围在不同时期呈现出不同的特征;②季节性移民社区形态存在差异,可以归类为交融性社区、优势性社区,共享性社区,纯粹性社区。③季节性移民社区是差异化的"美好生活"需求、独特的长寿资源及乡村生活环境、外来商业资本、地方政府调控和利益共生等"五力驱动"的结果,不同发展阶段其主导动力和作用方式存在差异。