Inductive research in last-mile delivery routing: Introducing the Re-Gifting heuristic

The last-mile problem presents a daunting challenge for many logistics service providers, especially some 7000 small, localized operations for whom the cost of complex software solutions is often prohibitive. As a result, last-mile dispatchers rely on simple heuristics to ensure adequate customer service at an acceptable cost. This research effort extends prior qualitative work by developing and testing a simple vehicle routing heuristic, based on behaviors observed in practice, that prioritizes customer service over cost against other simple vehicle routing heuristics across a variety of environments using simulation. The results support the inclusion of a customer service focus in vehicle routing and the addition of such heuristics to existing algorithm portfolios, specifically in urban areas with well-developed highway systems.     

文化如何成为经济学研究的对象

经济学研究对象经历了从纯客观物质变量向客观物质与主观精神结合的变量以至最终向纯主观精神变量逐次递进的扩展过程。文化精神通过影响经济行为主体的行为选择从而对微观经济运行和宏观经济发展产生重要影响。作为一种主观精神要素,文化精神曾经长期被主流经济学排斥在经验实证理论体系之外。经过诺斯、舒尔茨等人搭建的曲折理论通道,文化精神最终进入了经济学研究的核心概念范式集,成为经济学家分析不同国家、区域经济发展差异存在原因的不可或缺的一个基本理论视角。文化精神对经济的作用则主要表现为导向作用、激励作用、规约作用三个方面。     

Back to Buchanan? Explorations of welfare and subjectivism in behavioral economics

In light of behavioral findings regarding inconsistent individual decision-making, economists have begun to re-conceptualize the notion of welfare. One prominent account is the preference purification approach (PP), which attempts to reconstruct preferences from choice data based on a normative understanding of neoclassical rationality. Using Buchanan’s notion of creative choice, this paper criticizes PP’s epistemic, ontological, and psychological assumptions. It identifies PP as a static position that assumes the satisfaction of given ‘true preferences’ as the normative standard for welfare. However, following Buchanan, choice should be understood dynamically as a process whereby preferences constantly regenerate. Accordingly, the meaning of welfare emerges from an ongoing quest for individual self-constitution. If this holds true, then rationality axioms cannot serve as a priori normative standards. Instead, creative imagination and learning processes must remain central to any understanding of welfare in economics.     

基于三阶段DEA模型的中国城市效率研究

使用三阶段DEA模型,在排除外部环境条件和随机误差影响的情况下,对2001—2007年中国266个地级及以上城市的效率进行了评价,并探讨了中国城市效率的环境响应机制。结果显示:中国城市效率受城市空间格局、区位条件、政府竞争环境、人口环境和历史条件等外部环境条件以及随机误差的影响;具体而言,外部城市影响程度强或区位条件较好有助于降低城市要素投入的冗余水平;政府竞争环境较激烈或历史发展条件较优越会促使城市要素投入冗余水平提高;人口环境对城市各类要素投入的影响存在显著差异。     

基于灰色系统模型的城乡建设用地规模预测——以常德市鼎城区为例

土地利用总体规划是区域性的综合规划,为地方性的经济发展提供科学和法律依据.建设用地的有效供给是地方经济发展基础,建设用地需求量预测是土地利用总体规划编制的核心,也是土地利用管理的依据.为了切实搞好常德市鼎城区的土地利用总体规划,使之更具有前瞻性、可操作性,必须切合实际地搞好建设用地需求规模和布局的预测.采用灰色系统模型,通过灰色关联度分析,建设用地发展与GDP、总人口、市镇人口、社会固定资产投资、人均GDP、第二产业产值、第三产业产值密切相关.基于这些因子,采用灰色系统模型法、建立GM(1,1)灰色模型,进行了2010年和2020年的城乡建设用地规模的预测.GM(1,1)模型可以进行长期预测,但预测仅反映一种趋势,综合考虑驱动因素的灰色线性组合模型更具有预测的可靠性.利用GM(1,1)模型和线性模型组合,进行城乡建设用地规模预测,可为土地利用总体规划提供可靠的保证.     

城市发展新机遇的选择——低碳城市模式探析

在城市化进程不断加快的情况下,能源供应紧张、环境污染等城市问题愈加严重,选择低碳经济城市这种新的发展模式将给我们带来新契机,从而有效解决城市化进程中复杂的环境和能源问题,促进城市可持续发展.低碳城市作为新型城市发展模式的重要组成部分,它不是简单的城市减排和能源增效,而是以构建可持续发展的生态城市作为其最终发展目标的.文章从新型城市发展模式中选取低碳城市加以认真分析,探讨低碳经济背景下的低碳城市内涵,介绍国内外低碳城市建设的实践,提出未来低碳城市建设的新思路.     

Migration,self‐selection and income distributions

Self‐selection in rural–urban migration is examined using three datasets from rural and urban China in 2002. We construct a migrant sample including both migrants who converted their hukou status from rural to urban (permanent migrants) and those who did not (temporary migrants). We find a strong positive selection for permanent migrants, but the selection for temporary migrants is ambiguous. We reach these conclusions by comparing migrants' counterfactual wage densities, assuming they are paid as rural local workers, to actual wage densities of rural local workers. Our results imply that permanent migration has negative effects on rural human capital accumulation and income levels.     

从“其他绿地”到“区域绿地”： 城市非建设用地下的绿地规划转型 与优化

新版《城市绿地分类标准》(CJJ/T 85—2017)以“区域绿地”代替“其他绿地”，这为城市非建设用地下绿地的保护利用提出了新的要求和目标。解读新标准指导下城市非建设用地中的绿地建设发展要求并进行科学合理的规划，是响应当前城市绿色发展新形势和满足人民日益增长的美好生活新需求所面临的重要课题之一。聚焦从“其他绿地”到“区域绿地”的分类调整，分析新标准下区域绿地的内涵和特征。以河北省承德市为例，结合城乡发展需求，阐述区域绿地规划的核心转型思路。并从目标、内容、方法和评价等方面，论述区域绿地设定下城市非建设用地中绿地规划的具体内容和方向。最后从空间政策、发展引导、部门合作和大众参与等方面，提出了规划实施保障优化的策略。以“区域绿地”的解读为源，聚焦当前城市建设用地内外绿地规划建设割裂的现状问题，提出区域绿地规划的转型优化措施和实践经验，以期为新时代中国城市绿色空间的拓展与优化提供参考。