Instrumental Variables Two-Stage Least Squares (2SLS) vs. Maximum Likelihood Structural Equation Modeling of Causal Effects in Linear Regression Models     

Alberto Maydeu-Olivares  Dexin Shi  Yves Rosseel 《Structural equation modeling》2013,20(6):876-892

In the presence of omitted variables or similar validity threats, regression estimates are biased. Unbiased estimates (the causal effects) can be obtained in large samples by fitting instead the Instrumental Variables Regression (IVR) model. The IVR model can be estimated using structural equation modeling (SEM) software or using Econometric estimators such as two-stage least squares (2SLS). We describe 2SLS using SEM terminology, and report a simulation study in which we generated data according to a regression model in the presence of omitted variables and fitted (a) a regression model using ordinary least squares, (b) an IVR model using maximum likelihood (ML) as implemented in SEM software, and (c) an IVR model using 2SLS. Coverage rates of the causal effect using regression methods are always unacceptably low (often 0). When using the IVR model, accurate coverage is obtained across all conditions when N = 500. Even when the IVR model is misspecified, better coverage than regression is generally obtained. Differences between 2SLS and ML are small and favor 2SLS in small samples (N ≤ 100).  相似文献   

类比推理的形式化探析     

胡毅敏 《昆明师范高等专科学校学报》2013,(1):55-57

类比推理是一种重要的推理,仅仅由属性的相似性去解释类比是不够的,应该从形式上对类比推理进行深入的探究.类比是源域S和目标域T之间的结构保持映射fM.在类比推理的过程中,对源域S的选择、对结构保持映射的要求以及对类比迁移的控制,都会影响类比推理的关联性和可靠性.  相似文献   

Some Theory for the Conservation of Contemporary Art     

Rosario Llamas-Pacheco 《文物保护研究》2020,65(8):487-498

ABSTRACT

This article analyzes different ontological categories and how they relate to the conservation of contemporary art. Faced with the necessity of apprehending the work of art from an ontological point of view, a theoretical approach is made on the concepts that most affect the conservation of contemporary art: quiddity, truth-authenticity, identity, quality, consistency, and interpretation. These are analyzed from an empirical perspective, based on the experience of conservation and restoration. Since conserving and restoring require making decisions that will affect the material and conceptual plane of the works, several possible paradigms that must be introduced into the deontological code of the profession are analyzed. In addition, the study of a new paradigm is provided, that of the death of the work of art. This paradigm can serve as a frame of reference, given the impossibility of bringing the ‘Truth’ of the artwork into the world of the sensitive. This may occur due to different conditioning factors and limitations of a material, technical, or intentional type, which affect issues that were once established as essential to the entity. On the other hand, different types of time that are related to the conservation of contemporary art are studied: biological time, the eternal present of the work, time as a constructor agent, and destructive time as a facilitator of the appearance of ruin or ruin-relic in the work of art.  相似文献   

兼收并蓄和而不同——翻译的辩证思考     

姚登宝 《培训与研究》2007,24(6):133-134,F0003

从辩证思辨的视角，运用联系、发展、矛盾的观点，文章对目前译界两种众说纷纭的理论流派逐一透视，并分析其利弊得失，认为各种理论都有其合理性和阐释力，同时也存在理论偏向（见）和理论缺陷。提出翻译研究必须坚持翻译的本体，以源语言及文本为基础、为核心，突出译者的认知主体作用，兼顾作者／读者、源影译语、社会／文化及其它边缘性影响因素等观点。  相似文献   

MUST的用法     

欧阳岱峰 《泉州师范学院学报》2001,19(1):122-124

本文论述ｍｕｓｔ的不同用法,对其否定形式、推测含义及名词功能进行分析。  相似文献   

职业教育功能研究的思考   总被引：1，自引：0，他引：1  

王川 《职教通讯(江苏技术师范学院学报)》2008,23(9)

“功能”、“职能”、“作用”、“价值”等概念既有联系,又有区别。职业教育功能可以分为三个层面：本体功能、客观功能和价值功能,这三个层面应该分别从逻辑层面、事实层面和价值层面进行研究。  相似文献   

含意理论在小说翻译中的应用     

钟海英 《广东技术师范学院学报》2008,3(4):46-50

含意在文学作品中是极为常见的现象。小说作为文学作品的重要表现形式,基本上遵循一般的语言规范,但也经常利用独特的句法、词法手段增加作品的含意性。因此,翻译时妥善处理含意问题,才能真正译出原文的意义。本文以《名利场》原作及杨必中译本为例,对比分析了英汉两种语言的常规性以及它们在使用中各自产生的特性,认为含意理论中的"含意推导"和"合作原则"可用来指导译者正确理解原文并在翻译中恰如其分地表述出来,使译文尽量与原文的意义达成真正对等。  相似文献   

基于专家系统设计过程的盲目搜索技术优化策略的探讨   总被引：1，自引：0，他引：1  

杨磊 《洛阳师范学院学报》2008,27(2):96-98

分析了盲目搜索技术的特点、算法、搜索过程、时间复杂度和空间复杂度,并在此基础上讨论了盲目搜索技术面向专家系统的设计过程所存在的缺点。依据专家系统知识表示和推理过程的特点,提出了一种改进的搜索方法——跳棋法,并阐述了跳棋法搜索策略的基本思想和算法过程,描述了这种搜索方式更适用于专家系统设计过程的原因。  相似文献   

新闻获得性属性根源分析     

杨保军 《湖南大众传媒职业技术学院学报》2008,8(5):5-10

新闻获得性属性是新闻在非纯粹的新闻关系名义下具有的属性,它是在本体属性基础上获得或凸现出来的一些新的属性。这一属性用来反映指称新闻在传收过程中获得的本体属性之外的属性。新闻的获得性属性主要根源于新闻本体自身的属性、各种新闻传收关系以及新闻传收环境提供的条件和机遇。只有理解和把握了新闻的获得性属性,才能真正理解现实的新闻传播。  相似文献   

意识还原与笛卡尔复仇     

柯文涌 《科学技术哲学研究》2021,38(2):40-45

破除意识的神秘性,使得意识成为可科学理解的物理或生物现象是秉承科学主义传统的当代心灵哲学、认知科学和脑神经科学等多学科一直不懈努力的哲学——科学议题。鉴于笛卡尔哲学中的意识概念并未真正经过理性法庭的审判,使得意识祛魅具有不彻底性,还原论者开始了意识的科学还原和概念取消多种进路尝试。笛卡尔主义者内格尔针对还原主义论证提出现象学论证,由此指明意识还原的科学纲领在方法论上同样犯了范畴错误,即在科学的还原过程中遗漏掉主观性。还原论者忙于通过修改物理本体论承诺来消除主观性难题,结果为神秘主义、突现论和目的论开了方便之门。  相似文献