改进的灰色灾变模型在干旱预测中的应用

为提高传统的GM(1,1)模型精度,分别从原始数据序列检验和建立残差修正模型两方面进行了改进,并将改进的灰色灾变模型与不进行原始序列检验的GM(1,1)1模型和对原始数据序列进行检验的GM(1,1)2模型进行了比较。结果表明:改进的灰色灾变模型精度最高;运用该模型预测榆林市未来可能发生干旱的年份分别为2012年、2015年和2019年。     

对抗旱服务组织发展的思考

叙述江西省抗旱服务组织现状,分析了制约抗旱服务组织发展的问题,提出了抗旱服务组织发展对策.     

石家庄西部山区干旱成因及抗旱减灾对策研究

通过分析石家庄西部山区4个代表监测站的历年降水资料,利用《旱情等级标准》中农业旱情指标与等级,12．22009年春季石家庄西部山区的旱情为例,分析了旱灾主要成因,并提出抗旱减灾对策。     

Default- and call-adjusted duration for corporate bonds

Call and default can potentially alter the timing and amounts of promised cashflows for callable, corporate bonds. While prior research has indicated the theoretical importance of adjusting Macaulay duration for the impacts of default and call, the question of their relative impact remains a matter of debate [The High Yield Debt Market, Dow Jones Irwin, New York, 1990, p. 18; J. Finan. 53 (1998) 2225]. We develop a theoretical analysis incorporating both default and call effects on duration and test its implications employing a previously unexplored data base of Canadian, investment grade, corporate bond indices containing an unusual provision making it possible to identify callable and noncallable indices.     

Cross-sectional surveys: Inferring total eventual time in current state using only elapsed time-to-date

We focus on snapshot surveying of sub-populations whose members are in a temporary state and where one of the questions asked is the elapsed time already spent in that state. From these answers we develop probabilistic and statistical procedures to estimate the distribution of total time that will eventually be spent in that state by any random individual who enters the state. The method relies on a selection bias often found in temporal sampling, sometimes called “random incidence” or “longevity bias.” We develop results for several types of sampling, including random and fixed times of surveying, random and fixed times of entering the state, and sampling only those who have already spent some minimal specified time in the targeted state. An example with post-doc data is included to demonstrate the steps.     

Money Allocation to Out-of-Home Leisure Activities and the Organization of These Activities in Time and Space

Monetary budgets influence activity participation and related travel as they demarcate limits on how people organize their activities in time and space. In this paper, we are interested in money allocation to out-of-home leisure activities and how this is affected by duration, sociodemographics, and time-location variables. Analyses were carried out by applying a seemingly unrelated regression model to a leisure activity data set. The analyses revealed that expenditures for out-of-home leisure activities are influenced by the variables mentioned above. Moreover, the results indicate that there is a substitution between expenditure of each activity.     

论我国抗旱立法的完善

旱灾一直是我国的主要自然灾害之一,它影响粮食安全、饮用水安全、生态安全。面对大旱,我们必须深刻反思我国现有抗旱立法工作的不足之处,并通过加强防灾减灾与水资源管理方面立法,完善《森林法》的内容,加快制定农业保险法、农田水利法等农业立法,使我国抗旱工作有法可依,提高我国应对旱灾的能力。     

浅析需求导向下如何提升湾沚区水旱灾害防御信息化水平

湾沚区水旱灾害频发,严重影响地区社会经济发展和危及人民生命财产安全。水旱灾害防御信息化系统是防汛抗旱的重要手段,为防汛抗旱的决策和调度提供技术支撑。本文对湾沚区水旱灾害防御信息化建设背景、需求和现状进行梳理和分析。以功能需求和性能需求为导向,针对湾沚区信息化建设存在的不足,提出监测体系、预警平台、终端服务、运维机制等方面的措施建议,为水旱灾害防御信息化建设提供思路与借鉴。     

我国城乡教育不平等与收入差距扩大的动态研究

通过构造一个内生收入函数模型,利用省级面板数据,本文实证研究了我国城乡教育不平等与收入差距扩大的动态关系.研究发现:城乡教育不平等是收入差距扩大的一个重要原因,城乡教育差距第上升1%,城乡收入差距将上升6.4个百分点;并且随着市场化改革的深入,教育差距对收入差距的影响越来越重要.     

城市干旱风险管理系统协同演化研究

基于对城市干旱风险管理系统的分析,借鉴B-Z反应模型,建立了城市干旱风险管理系统三维Logistic协同演化模型,分“危机-应对”和“风险常态化”两种管理模式设计仿真情景,揭示在防备、响应与恢复3个子系统相互作用和政府跨组织协同度支撑下城市干旱风险管理系统的动态演进机制,并对鄂尔多斯市进行了案例模拟分析。研究结果表明:在“危机-应对”管理模式下,由于忽视城市干旱风险防备能力的建设,城市干旱风险防备能力处于较低水平,即使是增强子系统之间的协同水平,也很难提高城市干旱风险响应能力水平。无论是组织弱协同还是组织强协同条件下,干旱恢复能力都会有所增长,协同水平越强,干旱恢复水平越高。但是在干旱防备能力和响应能力均较低的情况下,干旱灾害造成的城市损失均较大,干旱恢复水平越高,意味着付出的干旱恢复成本越高,这正是“危机-应对”管理模式被动性、滞后性所造成的后果。在“风险常态化”管理模式下,在城市干旱风险防备能力水平都很强的情况下,组织强协同比组织弱协同会更加有力地推进城市干旱防备能力、响应能力和恢复能力的同时快速增长;组织强协同比组织弱协同会更加促进3个子系统之间的互动,从而促进3个子系统之间的平衡发展,对于城市应对干旱更加有效率。在城市有限资源约束下,3个子系统之间存在相互制约作用,组织强协同比组织弱协同在更加平衡子系统之间的发展的同时,会限制具有发展最优势的防备能力达到弱协同下的水平。