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.     

"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     

国家权力、企业家精神与企业经营——以通用机器有限公司(1946~1949)为例

通用机器有限公司是国民政府资源委员会在抗战胜利后创办于上海的国有机械制造企业。资源委员会委派私营企业家马雄冠作为公司负责人,并肯定了马雄冠的"纯商业化"经营路线,使公司能边基建边投产运营,缓解了资金压力,在恶劣的局势下取得较好的成绩。尽管马雄冠为公司注入了企业家精神,但公司的销路问题有赖于资源委员会的重工业建设,其技术引进也由资源委员会负担了大笔先期资金,因此,该公司的成功是良好政企关系的产物。     

抗战中的知识分子

作者通过对甲午战争至全面抗战爆发历史的回顾,分析期间中国知识分子的思想变化.并分析抗战爆发后知识分子通过不同的方式积极投入救亡运动,重新认识抗战期间的知识分子的真实处境和历史,提出应更理性、客观的去看待抗战时期的知识分子的选择,无论是自由主义知识分子、马克思主义知识分子还是新儒家知识分子,对近代中国文化的追求,根本上都是“三民主义”.     

明初大运河南旺分水枢纽水工技术考

明朝初年,国脉皆仰东南,为解决南方粮财物的北运问题,宋礼和白英受命组织修建了大运河山东段南旺分水枢纽。该枢纽主要包括引汶济运、导泉补源、设立水柜和置闸节流四个组成部分。其中,引汶济运是工程之重点,包括戴村坝、小汶河、南旺分水以及配套工程等四个子系统。这些水利设施组成一个和谐的系统工程,保证了该段运河的水量稳定充足,从而实现了大运河500余年的正常通行。南旺分水枢纽代表了我国古代运河水工的最高科学技术成就,堪称世界水利史上的一大经典范例。     

卢梭回归自然的美学之境

卢梭的“自然美”思想丰赡深邃,精远宏阔.从美育目标、理念、重点三个层面梳理了卢梭自然主义美育思想的核心内容,将其教育特点归纳为整体性、平民性、情感性和自然性,并着重阐述了这一思想对新时期我国美育工作的四个重要启示:即注重美育工作的辩证性;尊重美育实践的主体性;激励美育过程的情感性;倡导美育内容的生态性.     

Quantifying Animal Trajectories Using Spatial Aggregation and Sequence Analysis: A Case Study of Differentiating Trajectories of Multiple Species

The increasing availability of telemetry data with high spatial and temporal resolution promises to greatly advance scientific understandings of the movement patterns of individual organisms across space and time. The amount of data provided by such methods, however, can be challenging to analyze and interpret. In this study, we present a new approach for analyzing animal movements that aggregates telemetry locations into spatial clusters and extracts the information from sequences formed by individuals passing through these spatial clusters. We applied this integrated approach of spatial aggregation and sequence analysis to quantify and compare trajectories of cattle (Bos taurus), mule deer (Odocoileus hemionus), and elk (Cervus elaphus) tracked by automated telemetry at the Starkey Experimental Forest and Range in northeastern Oregon, USA. Our approach effectively differentiated movement patterns of the three species. It provides a useful mean of quantifying movement patterns of species in a landscape.