关于在城市低收入人群中推广小额人身保险的思考

我国人身保险市场现有的险种,大都针对城市富人和中产阶层,而实际上,社会低收入者比前者面临更多的人身风险。目前在世界多个发展中国家得到推广的小额保险恰可解决这一问题。小额保险具有保费低、产品设计简单、定位准确等特点。在推广该险种的过程中,保险公司要特别注意结合我国国情,创新险种设计,选择合适的销售渠道和保费收取模式,实现经济效益和社会效益的"双赢"。     

American-style options in jump-diffusion models: estimation and evaluation

We propose dynamic programming coupled with finite elements for valuing American-style options under Gaussian and double exponential jumps à la Merton [J. Financ. Econ., 1976, 3, 125–144] and Kou [Manage. Sci., 2002, 48, 1086–1101], and we provide a proof of uniform convergence. Our numerical experiments confirm this convergence result and show the efficiency of the proposed methodology. We also address the estimation problem and report an empirical investigation based on Home Depot. Jump-diffusion models outperform their pure-diffusion counterparts.     

基于混合集合规划的多场景应急设施选址优化

多场景应急设施选址问题具有约束复杂、时效性强、规划周期短等特点。以混合集合规划为算法框架的自然约束语言NCL能对该问题进行建模与求解。以一个典型多场景应急设施选址问题为例,证明了NCL可有效求解该类问题。     

Is econometrics useful for private policy making? A case study of replacement policy at an auto rental company

The goal of this paper is to illustrate the potential usefulness of econometrics as a tool to assist private policy makers. We provide a case study and detailed econometric analysis of the automobile replacement policy adopted by a large car rental company. Unlike public policy making–where the benefits from using econometric models and “science-based” approaches to policy making are hard to quantify because the outcomes of interest are typically subjective quantities such as “social welfare”–in the case of firms there is an objective, easily quantifiable criterion for judging whether policy A is better than policy B: profits. We introduce and estimate an econometric model of the rental histories of individual cars in the company’s fleet. Via stochastic simulations, we show that the model provides a good approximation to the company’s actual operations. In particular, the econometric model is able to reproduce the extraordinarily high rates of return that the company obtains on its rental cars, with average internal rates of return between purchase and sale of approximately 50%. However, the econometric model can simulate outcomes under a range of counterfactual vehicle replacement policies. We use the econometric model to simulate the profitability of an alternative replacement policy under pessimistic assumptions about the rate maintenance costs would increase and rental rates would have to be decreased if the company were to keep its rental cars longer than it does under the status quo. Depending on the vehicle type, we find that the company’s expected discounted profits would be between 6% to over 140% higher under the suggested alternative operating strategy where vehicles are kept longer and rental rates of older vehicles are discounted to induce customers to rent them. The company found this analysis to be sufficiently convincing that it undertook an experiment to verify the predictions of the econometric model.     

城市群协调发展:内涵、概念模型与实现路径

城市群是一定地域内的一组相互密切联系的城市,这组城市之间存在着规模等级和空间结构及功能分工,具有共同的利益目标和与之相对应的集体行为。城市群协调发展是在内生与外生动力双重作用下系统秩序逐渐形成、整体发展能力不断增强的演进过程,包括城市群内部的各个城市之间相互开放,形成有利于资源和要素自由流动,实现资源和要素优化配置的环境;通过竞争优选或者政府推动,形成以产业分工和合作为主要内容的功能分化,依此形成日益密切的经济联系和发展上的依赖、互动关系;通过城市之间的平等协商或上一级政府的安排,共同解决跨区域的交通、通信、资源开发、环境保护等公共领域的问题,降低交易成本。实现城市群协调发展的路径有城市群发展战略与规划、政策法规、空间管制与生态环境治理、要素流动、企业跨区域发展以及产业分工与合作。     

关于城市竞争力及提升中国城市竞争力的思考

随着知识经济兴起和中国入世,中国与世界上其他国家的竞争以及国内各地区之间的竞争成败都将取决于城市的竞争力.以城市为代表的多维空间载体正以多种复杂的方式进行着全球资源、市场、生存和发展空间与发展机会的争夺与较量,城市已经成为全球经济社会发展的焦点.中国城市发展及其竞争力增强要在研究城市发展理论和借鉴国内外成功经验的基础上,通过树立经营城市的意识、明确城市地位以及加大产业集中度等多种手段或措施才能实现.     

数控仿真软件在数控教学中的应用——以车削零件加工为例

为了提高《数控机床与编程》课程的教学质量,把数控仿真软件应用引入到课堂教学,并结合车削零件加工,展示数控仿真软件整体加工过程,结果极大提高学生课堂的兴趣,提高了教学效果,也提高学生的数控编程能力和数控机床操作能力,保证了教学质量。     

《城市园林绿化资源调查技术规程》的研制

城市园林绿化资源调查是城市园林绿化行业管理的一项基础工作,是对现行城建统计制度的重要补充和完善。文章通过研制规程,建立了城市园林绿化资源的概念,规定了调查的内容、组织方法,调查因子的定义、分类标准与调查方法,调查图斑区划,前期准备工作,外业调查,统计计算,调查质量管理,调查成果报告等技术要求,并应用于2010年开展的徐州市城市园林绿化资源调查中,取得了较好的成果。