Clinical outcome measurement: Models,theory, psychometrics and practice

In the last decade much has been made of the role that models play in the epistemology of measurement. Specifically, philosophers have been interested in the role of models in producing measurement outcomes. This discussion has proceeded largely within the context of the physical sciences, with notable exceptions considering measurement in economics. However, models also play a central role in the methods used to develop instruments that purport to quantify psychological phenomena. These methods fall under the umbrella term ‘psychometrics’. In this paper, we focus on Clinical Outcome Assessments (COAs) and discuss two measurement theories and their associated models: Classical Test Theory (CTT) and Rasch Measurement Theory. We argue that models have an important role to play in coordinating theoretical terms with empirical content, but to do so they must serve: 1) as a representation of the measurement interaction; and 2) in conjunction with a theory of the attribute in which we are interested. We conclude that Rasch Measurement Theory is a more promising approach than CTT in these regards despite the latter's popularity with health outcomes researchers.     

Playing with molecules

Recent philosophy of science has seen a number of attempts to understand scientific models by looking to theories of fiction. In previous work, I have offered an account of models that draws on Kendall Walton’s ‘make-believe’ theory of art. According to this account, models function as ‘props’ in games of make-believe, like children’s dolls or toy trucks. In this paper, I assess the make-believe view through an empirical study of molecular models. I suggest that the view gains support when we look at the way that these models are used and the attitude that users take towards them. Users’ interaction with molecular models suggests that they do imagine the models to be molecules, in much the same way that children imagine a doll to be a baby. Furthermore, I argue, users of molecular models imagine themselves viewing and manipulating molecules, just as children playing with a doll might imagine themselves looking at a baby or feeding it. Recognising this ‘participation’ in modelling, I suggest, points towards a new account of how models are used to learn about the world, and helps us to understand the value that scientists sometimes place on three-dimensional, physical models over other forms of representation.     

基于贝叶斯原理的随机波动率模型分析及其应用

基于贝叶斯原理,对随机波动性模型进行研究,并将随机波动率模型应用股市风险价值VaR的估计与预测.针对中国股市数据进行的实证结果表明,与GARCH模型相比,随机波动率模型能更好地描述股票市场回报的异方差和波动率的序列相关性;基于随机波动率的VaR较GARCH模型的VaR具有更高的精度.     

聚乙烯树枝化的新模型

作者考虑到聚合物的形态结构和能带特点,应用近似的平板能带理论,说明了电子和空穴注入的不同方式和途径。同极性空间电荷的形成过程中存在着两种相互矛盾的作用,一方面它降低针尖附近介质中的电场强度,有提高树枝起始电压的趋势;另一方面注入过程中正负载流子的复合或热电子的作用,有降低树枝起始电压的倾向。模型中首次提出了在聚合物的树枝潜伏期内存在着一个低密度区的过渡阶段,并用条纹图象法证明了这个区域的存在。其他一些特殊试验支持了新模型的构思。     

反语生成和理解的机制研究

以“基于心理模型的语用推理”假说为理论框架。参照心理学及认知语言学的最新成果,从“认知连续统”的角度出发,对反语的认知机制做一尝试性的探索,发现：找到存在于心理模型中的有关某一范畴的正-反相邻连续统是理解反语的关键,它为反语中显性表达和隐性表达的定位,进而为整个反语话语的生成和理解提供一个可以解释的心理支持。     

平泉县生态经济特征及其分区开发整治模式

在对平泉县生态经济特征分析的基础上,运用生态经济学观点从区域总体功能出发,根据自然生态因素和社会经济因素的特点及内在联系所构成的空间组合形式的相似性和差异性,对平泉县进行生态经济分区,展示整体与局部间的矛盾,识别生态经济发展因素和制约因素,提出生态经济的开发方向、途径和对策,为资源的永续利用、生态的良性循环、经济持续发展提供导向性决策的科学依据     

英语作为第二语言的多媒体语音数据库设计制作及初步测试

由于中国方言的发音不同,从而影响了作为第二语言的英语发音也出现了不同的特色,与第一语言为英语的发音口型也出现了很大的差别,在英语的普及的今天,以英文作为第二语言的人们也日益增多,因而有必要建立一个专门针对英语为第二语言的多媒体语音数据库.本数据库参照AVICAR[1]的方法进行收集,介绍了数据库的特点、录音内容、存储形式,最后对该数据库进行初步辨认测试,并将测试结果与标准测试的结果进行比较.初步测试结果发现收集的数据库识别率大大降低,可见建立该数据库是很有必要的.     

干酪根热解平行反应模型中表观活化能与视频率因子的关联

本文考察了三种类型干酪根以及抚顺和茂名油页岩热解反应的动力学特性,对由平行反应模型所求得的表观活化能及视频率因子进行了数学关联。关联式表明,视频率因子的对数值与表观活化能成一直线关系。由此关系可以推出,所有平行反应在某一特定温度下具有一个相同的反应速率常数。根据直线的斜率,还可以比较不同类型干酪根热降解反应的难易程度。     

改进的HMM系统在英语语音合成中的研究

根据英语语言所具有的一些特性对HMM模型进行改进,设计出适合英语语音合成的上下文属性集以及用于模型聚类的问题集,提高了其建模和训练效果。此外,借助HTK和Festival等工具,以基频和声道谱参数为训练参数,最终实现此英语语音合成系统。从所合成语句的效果来看,合成语音整体稳定流畅,而且节奏感比较强。     

吉林市市区交通需求分析

在收集了吉林市经济发展与城市用地的资料后,对吉林市市区的交通需求情况进行了分析与预测,从而证明吉林市道路网规划是正确的和科学的.