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.     

语义场理论对科技术语翻译的启示从——“水资源管理”一词的英汉互译谈起

科技术语在不同语言之间的翻译是一个复杂的语义匹配过程，如何在考虑相关术语使用现状的基础上将新产生的科技术语准确翻译为其它语言是科技工作者和术语研究者关注的重要问题。以语义场理论为分析框架，通过分析以"水资源管理"及其相关术语为代表的英汉互译，结果发现：不同科技术语在同一语义场所涵盖的语义范围将会随着相关研究深化带来的术语界定细化而发生相应的动态变化；新兴科技术语的翻译要充分考虑其所在语义场其它相关科技术语的翻译先例和使用现状所带来的影响，在翻译准确性和解读便利性之间做出适当的平衡。这是造成"水资源管理"及相关术语英汉互译处理极为复杂的重要原因之一，需要科技翻译者在工作实践中多加注意。     

运营滞后与信用担保互换下的项目投资决策模型

在项目投资面临运营滞后以及债务融资约束的情形下，基于实物期权框架构建了企业家签订信用担保互换契约的两阶段投资决策模型。运用动态规划以及均衡定价方法，给出了企业家股权及期权价值的显示表达，得到了两个阶段担保成本满足的代数方程，并进一步分析了运营滞后和信用担保下企业家的最优投资决策问题。数值结果表明：外部运营时滞会提高杠杆率，导致企业家提前投资，同时会提高企业家第一阶段债务融资的担保成本，但会降低第二阶段债务融资的担保成本；随第一阶段投资额度逐渐增大，企业家的最优投资水平呈U型变化，第一阶段债务融资时的担保成本单调递减，而第二段债务融资时的担保成本呈现倒U型；企业家两个阶段的融资缺口对项目最优投资水平、最优破产水平以及担保成本有显著影响。     

泌阳凹陷泌301 井区不同流动单元产能分析

在沉积微相、储层物性特征分析的基础上，选取孔隙度、渗透率、流动带指数等参数，对泌阳凹陷赵凹油田泌301 井区核三段油层组进行流动单元划分。依据流动带指数的大小，将研究区目的层段划分为A、B、C、D 和E 等5 类流动单元。通过研究发现，各类流动单元与物性、岩性、沉积微相之间具有较好的对应关系，同时对不同流动单元产能进行了分析。研究结果表明，流动单元的划分能够真实客观地反映储层物性差、非均质性强的地质特点，单井产能与流动带指数有较好的乘幂关系，不同流动单元产能差异较为明显，物性最好的A 类流动单元产能最高，物性最差的E类流动单元产能最低。     

Optimization of Cascade‐Resilient Electrical Infrastructures and its Validation by Power Flow Modeling

Large‐scale outages on real‐world critical infrastructures, although infrequent, are increasingly disastrous to our society. In this article, we are primarily concerned with power transmission networks and we consider the problem of allocation of generation to distributors by rewiring links under the objectives of maximizing network resilience to cascading failure and minimizing investment costs. The combinatorial multiobjective optimization is carried out by a nondominated sorting binary differential evolution (NSBDE) algorithm. For each generators–distributors connection pattern considered in the NSBDE search, a computationally cheap, topological model of failure cascading in a complex network (named the Motter‐Lai [ML] model) is used to simulate and quantify network resilience to cascading failures initiated by targeted attacks. The results on the 400 kV French power transmission network case study show that the proposed method allows us to identify optimal patterns of generators–distributors connection that improve cascading resilience at an acceptable cost. To verify the realistic character of the results obtained by the NSBDE with the embedded ML topological model, a more realistic but also more computationally expensive model of cascading failures is adopted, based on optimal power flow (namely, the ORNL‐Pserc‐Alaska) model). The consistent results between the two models provide impetus for the use of topological, complex network theory models for analysis and optimization of large infrastructures against cascading failure with the advantages of simplicity, scalability, and low computational cost.     

Do information,price, or morals influence ethical consumption? A natural field experiment and customer survey on the purchase of Fair Trade coffee

We address ethical consumption using a natural field experiment on the actual purchase of Fair Trade (FT) coffee in three supermarkets in Germany. Based on a quasi-experimental before-and-after design the effects of three different treatments – information, 20% price reduction, and a moral appeal – are analyzed. Sales data cover actual ethical purchase behavior and avoid problems of social desirability. But they offer only limited insights into the motivations of individual consumers. We therefore complemented the field experiment with a customer survey that allows us to contrast observed (ethical) buying behavior with self-reported FT consumption. Results from the experiment suggest that only the price reduction had the expected positive and statistically significant effect on FT consumption.     

同义义场义位的配价研究

主要依据商务印书馆第5版《现代汉语词典》的释义，对黄伯荣、廖序东主编的《现代汉语》、胡裕树主编的《现代汉语》、张斌主编的《新编现代汉语》、邢福义主编的《现代汉语》、杨润陆编的《现代汉语》、唐朝阔、王群生主编的《现代汉语》等6部高校教材中所收同义词的配价情况进行穷尽性研究，得出结论：两个或以上义位的本体和本体之间、本体和变体之间、变体和变体之间，均可构成同义义场。因此，我们研究同义义场，应该明确是此义位的哪个体与彼义位的哪个体构成同义义场。词性不同的各个词，不能构成同义义场，因为在语义领域，它们的主要语义特征不同。无论是哪一种同义义场，属于同一同义义场的各个义位的本体或变体，它们的配价都是相同的。     

除尘器区低温省煤器烟道数值模拟

为实现除尘器区低温省煤器的节能改造,基于FLUENT6.3软件,对除尘器区低温省煤器烟道的流场进行数值模拟研究。研究结果表明:除尘器前烟道内流场严重不均,转弯处有明显的高速区与漩涡区,局部速度高达32 m/s;加装低温省煤器后,两低温省煤器内流场不均,最大速度偏差系数达79.3%,严重影响低温省煤器的换热效果,同时会磨损、冲刷低温省煤器管路,危及低温省煤器的安全;除尘器入口处出现大面积的低速区域,导致进入除尘器后流场紊乱、除尘器电耗高、除尘效率低等现象,除尘器前烟道内整流消涡可以根治除尘器工作效率的问题。