A Graphical Tool for Interpreting Regression Coefficients of Trinomial Logit Models

Multinomial logit (also termed multi-logit) models permit the analysis of the statistical relation between a categorical response variable and a set of explicative variables (called covariates or regressors). Although multinomial logit is widely used in both the social and economic sciences, the interpretation of regression coefficients may be tricky, as the effect of covariates on the probability distribution of the response variable is nonconstant and difficult to quantify. The ternary plots illustrated in this article aim at facilitating the interpretation of regression coefficients and permit the effect of covariates (either singularly or jointly considered) on the probability distribution of the dependent variable to be quantified. Ternary plots can be drawn both for ordered and for unordered categorical dependent variables, when the number of possible outcomes equals three (trinomial response variable); these plots allow not only to represent the covariate effects over the whole parameter space of the dependent variable but also to compare the covariate effects of any given individual profile. The method is illustrated and discussed through analysis of a dataset concerning the transition of master’s graduates of the University of Trento (Italy) from university to employment.     

高速SDRAM控制器设计的FPGA实现

同步动态存储器(SDRAM)控制器通常用有限状态机实现,对于一般的设计方法,由于状态数量多,状态转换通常伴随大的组合逻辑而影响运行速度,因此,SDRAM控制器的速度限制了SDRAM存储器的访问速度。该文从结构优化入手来优化方法,利用状态机分解的思想将大型SDRAM控制状态机用若干小的子状态机实现,达到简化逻辑的目的,不仅提高了速度还节省了资源,对该类大型SDRAM控制器的实现有一定参考意义。     

三螺旋创新模式的理论探讨

基于非线性网状创新模型提出的“三螺旋场”和“三螺旋循环”概念进一步推进了三螺旋创新模式的理论研究。三螺旋场概念旨在解释在大学、产业和政府三股螺旋之间存在的相对独立和彼此作用的本质，说明三螺旋的生成原理、静态表现和动态演化特征。三螺旋的生成原理在于创新过程的非线性本质和多主体特征，静态表现为“内核外场模型”，而动态演化过程则在于纵向进化和横向循环。发生在三股螺旋之间的三螺旋循环揭示了在大学、产业和政府之间以人员、信息和产品流动为特征的相互作用和运行机制。     

毛泽东农村调查研究方法简论

毛泽东农村调查研究方法是一个完整的科学体系,马克思的辩证唯物主义和历史唯物主义是毛泽东农村调查研究方法的理论基础,即方法论。矛盾分析法和阶级分析法是毛泽东农村调查研究的基本方法。典型调查、类型调查、普遍调查、实地访问、开调查会、表格调查法、文献法、历史法等是毛泽东农村调查研究的方式和具体方法。     

蔡和森建党前社会调查活动探析

文章从蔡和森重视社会调查活动这一视角出发,分析了蔡和森社会调查活动的历史背景、特点及给我们的启示。     

实数域及四元数除环上有平方根的方阵

给出了实数域及实四元数除环上方阵有平方根的充分必要条件．     

乌鲁木齐县安宁渠镇社会经济变化调查报告

该文通过对乌鲁木齐县安宁渠镇的调查 ,揭示了城镇化进程中所发生的社会经济变化 ,以及这一变化所产生的后果 ;论述了加快安宁渠镇发展急需解决的问题 ,即社会意识整合问题、知识更新问题、基础设施建设问题、体制问题等。     

论科技期刊的品牌资本

科技期刊的品牌资本是其生存和发展的关键因素,品牌资本体现了社会效益与经济效益的同一性。品牌资本的价值回归是一个缓慢但却是相当稳定的过程。通过抽样调查和方差分析,定量说明了上述论点的正确性。     

唐叔虞封地考辨

西周初年晋国始祖唐叔虞始封地本是很明确的,即在今山西太原地区。这一点,从汉代开始已有定论,一直到明代,均无异说。其间虽汉司马迁、唐李泰给后人留下了一些可供"想象"的探讨空间,但总的来说,尚无过大歧异,从清代顾炎武方开了后人疑古之风。但顾说纯为一种假设推想,证据未足,后人沿袭顾说也未能有新的证据证明。班固以来唐叔虞封地晋阳说未可动摇。     

Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.