Book Review Multilevel Modeling Methodological Advances, Issues, and Applications

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教育游戏化:将课堂变成一场协同冒险游戏——以Classcraft为例

教育游戏化:将课堂变成一场协同冒险游戏——以Classcraft为例

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“对战”形式完成教学评测。学生按时完成任务可 以获得奖励,并用来升级角色的经验值(Experience Points,XP)——这将使其角色提高战斗水平并学 习新的技能。如果一个学生违反了课堂纪律,就会 失去生命值,甚至最终导致角色在“对战”中失败。 如果学生获得经验值点数,对相应角色及其团队都 有益处;相反,如果一个学生失去了生命值点数, 其团队的其他成员角色也会受到伤害,并且大家必 须完成各种额外任务。无论如何,学生们需要共同 努力才能使团队获得成功。一般而言,没有学生愿 意自己的不当行为损害团队利益,导致他人失败。 游戏团队中,学生还可以帮助彼此成长。例如,如 果学生的虚拟角色是一名战士,而队友因为上课迟 到面临生命值点数降低,则该学生可以通过完成额 外的学习任务来挽救队友。学生知道他们在课堂上 的行为会影响整个团队的进度、这会激励他们强化 课堂上的积极行为和团队合作,提升课堂学习效率。 Classcraft 每个月都会发布新的故事情节和场景供教 育工作者选择,帮助提升学生的课堂参与感 [19]。除 了在预制故事中添加课程任务外,Classcraft 还允许 教师自己编写课程,通过上传不同的学习任务来教 授不同的科目。根据在课堂活动中收集的数据,教 师还可以查看学生的行为并进行分析。
是以游戏软件为基础的学习,教育游戏(Educational Games)的设
计与开发是当前研究的主流方向。教育游戏模糊了学习与游戏、正式 学习与非正式学习的边界 [13];但是有别于教育游戏的软件性质(见表
1),教育游戏化是一套解决方案,服务于教育情境中的各类问题,
如激发学习者动机和兴趣、引导学习者面对学业失败、激发其学校生
研究表明,随着游戏在当代文化中的地位日益 提高,其在教育中能够扮演的角色也越来越多样化。 Classcraft 作为受到游戏启发开发的教育解决方案, 它对于学习的积极作用和游戏非常相似。

美国naep阅读能力评价框架之评价与借鉴

美国naep阅读能力评价框架之评价与借鉴

美国naep阅读能力评价框架之评价与借鉴NAEP(国家学术测评计划)阅读能力评价框架是美国教育部联盟的一份文件,为了帮助对学生的阅读能力进行有效评估,它提出了一个评估概念、多种工具和评估标准。

本文将介绍NAEP阅读能力评估框架,并讨论它的评估方法和借鉴意义。

一、NAEP阅读能力评估框架NAEP阅读能力评估框架认为,读者的阅读能力可以由其对以下不同类型的文本的理解程度来衡量:1、《信息文本》;2、《文学文本》;3、《参考文献》;4、《技术类文本》;5、《实际交往文本》;6、《社会语境文本》;7、《数学文本》。

根据这一读者阅读能力框架,NAEP阅读评估中采用了多种工具和评估标准。

二、NAEP阅读能力评估方法NAEP阅读能力评估框架采用了多种工具和标准,包括定性和定量方法。

调查测验是收集阅读能力信息的最常用方法,包括:回答问题/讨论、文本阅读请求/注解以及批判性思考。

定量数据分析是另一种常用的定量方法,包括错误分析、文本证据识别和内容熟悉度分析。

三、NAEP阅读能力评估的借鉴NAEP阅读能力评估框架提供了一种新的阅读理解评估标准,在理解阅读能力方面有重要影响。

其中,多种工具和评估标准可以明确每个文本所需的读者能力,有助于准确评估学生阅读能力水平。

此外,利用这一理论可以开发并应用先进的教学技术和方法,以改善阅读理解和促进不同文本理解能力的发展。

本文主要介绍了美国NAEP阅读能力评估框架,并讨论它的评估方法和借鉴意义。

在该评估体系中,采用了多种有效的评估工具和标准,加深了对阅读理解能力的认知,为培养学生的阅读理解能力提供了一个有效的框架。

在实践中,教师也可以参考和利用这一框架,为学生提供有效的教学支持。

学术期刊论文影响力评价模型研究

学术期刊论文影响力评价模型研究

学术期刊论文影响力评价模型研究随着学术界的迅猛发展,期刊论文成为学术交流的主要形式之一。

而期刊论文的影响力评价对于学术界来说至关重要。

本文旨在研究学术期刊论文影响力评价模型,探讨其背后的理论和方法。

学术期刊论文影响力评价模型是一种用于衡量论文在学术界中的影响力的工具。

其主要目的是帮助研究者更好地评估和比较不同期刊论文的质量和价值,以便做出更明智的研究方向选择和学术交流决策。

首先,学术期刊论文影响力评价模型需要确定评价指标。

常见的评价指标包括被引频次、被引用率、文章下载量、社交媒体关注度等。

被引频次是指一篇论文被其他学者引用的次数。

被引用率是指论文被引用次数与其所在领域论文总数的比率。

文章下载量是指一篇论文被下载的次数,而社交媒体关注度则衡量了一篇论文在社交媒体上的关注程度。

其次,学术期刊论文影响力评价模型需要确定权重分配方法。

权重分配方法决定了不同评价指标的重要性。

一种常见的权重分配方法是基于专家意见的主观评价法。

该方法通过专家的判断和主观评价来确定不同指标的权重。

另一种方法是基于数据分析的客观评价法。

该方法通过统计学和数据挖掘技术分析不同指标的相关性和影响力,从而确定权重。

不同的权重分配方法对于评价结果可能会产生不同的影响,因此需要根据具体情况选择合适的方法。

此外,学术期刊论文影响力评价模型还需要建立评价体系。

评价体系即评价指标和权重的组合。

评价体系应该考虑到不同领域和学科的特点和需求,以确保评价结果公正和准确。

评价体系应该经过充分的实证研究和验证,以确保其有效性和可靠性。

最后,学术期刊论文影响力评价模型需要进行实证研究和评估。

实证研究可以通过收集和分析实际数据来验证模型的有效性和准确性。

评估的目的是确定模型在实际应用中的效果和局限性,并提出改进措施和建议。

总之,学术期刊论文影响力评价模型的研究对于提高学术交流和研究质量具有重要意义。

通过建立科学有效的评价模型,可以更好地衡量和比较期刊论文的影响力,为学者们提供更可靠的参考和决策依据。

Advanced Mathematical Modeling Techniques

Advanced Mathematical Modeling Techniques

Advanced Mathematical ModelingTechniquesIn the realm of scientific inquiry and problem-solving, the application of advanced mathematical modeling techniques stands as a beacon of innovation and precision. From predicting the behavior of complex systems to optimizing processes in various fields, these techniques serve as invaluable tools for researchers, engineers, and decision-makers alike. In this discourse, we delve into the intricacies of advanced mathematical modeling techniques, exploring their principles, applications, and significance in modern society.At the core of advanced mathematical modeling lies the fusion of mathematical theory with computational algorithms, enabling the representation and analysis of intricate real-world phenomena. One of the fundamental techniques embraced in this domain is differential equations, serving as the mathematical language for describing change and dynamical systems. Whether in physics, engineering, biology, or economics, differential equations offer a powerful framework for understanding the evolution of variables over time. From classical ordinary differential equations (ODEs) to their more complex counterparts, such as partial differential equations (PDEs), researchers leverage these tools to unravel the dynamics of phenomena ranging from population growth to fluid flow.Beyond differential equations, advanced mathematical modeling encompasses a plethora of techniques tailored to specific applications. Among these, optimization theory emerges as a cornerstone, providing methodologies to identify optimal solutions amidst a multitude of possible choices. Whether in logistics, finance, or engineering design, optimization techniques enable the efficient allocation of resources, the maximization of profits, or the minimization of costs. From linear programming to nonlinear optimization and evolutionary algorithms, these methods empower decision-makers to navigate complex decision landscapes and achieve desired outcomes.Furthermore, stochastic processes constitute another vital aspect of advanced mathematical modeling, accounting for randomness and uncertainty in real-world systems. From Markov chains to stochastic differential equations, these techniques capture the probabilistic nature of phenomena, offering insights into risk assessment, financial modeling, and dynamic systems subjected to random fluctuations. By integrating probabilistic elements into mathematical models, researchers gain a deeper understanding of uncertainty's impact on outcomes, facilitating informed decision-making and risk management strategies.The advent of computational power has revolutionized the landscape of advanced mathematical modeling, enabling the simulation and analysis of increasingly complex systems. Numerical methods play a pivotal role in this paradigm, providing algorithms for approximating solutions to mathematical problems that defy analytical treatment. Finite element methods, finite difference methods, and Monte Carlo simulations are but a few examples of numerical techniques employed to tackle problems spanning from structural analysis to option pricing. Through iterative computation and algorithmic refinement, these methods empower researchers to explore phenomena with unprecedented depth and accuracy.Moreover, the interdisciplinary nature of advanced mathematical modeling fosters synergies across diverse fields, catalyzing innovation and breakthroughs. Machine learning and data-driven modeling, for instance, have emerged as formidable allies in deciphering complex patterns and extracting insights from vast datasets. Whether in predictive modeling, pattern recognition, or decision support systems, machine learning algorithms leverage statistical techniques to uncover hidden structures and relationships, driving advancements in fields as diverse as healthcare, finance, and autonomous systems.The application domains of advanced mathematical modeling techniques are as diverse as they are far-reaching. In the realm of healthcare, mathematical models underpin epidemiological studies, aiding in the understanding and mitigation of infectious diseases. From compartmental models like the SIR model to agent-based simulations, these tools inform public health policies and intervention strategies, guiding efforts to combat pandemics and safeguard populations.In the domain of climate science, mathematical models serve as indispensable tools for understanding Earth's complex climate system and projecting future trends. Coupling atmospheric, oceanic, and cryospheric models, researchers simulate the dynamics of climate variables, offering insights into phenomena such as global warming, sea-level rise, and extreme weather events. By integrating observational data and physical principles, these models enhance our understanding of climate dynamics, informing mitigation and adaptation strategies to address the challenges of climate change.Furthermore, in the realm of finance, mathematical modeling techniques underpin the pricing of financial instruments, the management of investment portfolios, and the assessment of risk. From option pricing models rooted in stochastic calculus to portfolio optimization techniques grounded in optimization theory, these tools empower financial institutions to make informed decisions in a volatile and uncertain market environment. By quantifying risk and return profiles, mathematical models facilitate the allocation of capital, the hedging of riskexposures, and the management of investment strategies, thereby contributing to financial stability and resilience.In conclusion, advanced mathematical modeling techniques represent a cornerstone of modern science and engineering, providing powerful tools for understanding, predicting, and optimizing complex systems. From differential equations to optimization theory, from stochastic processes to machine learning, these techniques enable researchers and practitioners to tackle a myriad of challenges across diverse domains. As computational capabilities continue to advance and interdisciplinary collaborations flourish, the potential for innovation and discovery in the realm of mathematical modeling knows no bounds. By harnessing the power of mathematics, computation, and data, we embark on a journey of exploration and insight, unraveling the mysteries of the universe and shaping the world of tomorrow.。

英文评价文献方法

英文评价文献方法

Literature ReviewWhat is a Literature Review?A literature review is a survey and discussion of the literature in a given area of study. It is a concise overview of what has been studied, argued, and established about a topic, and it is usually organized chronologically or thematically. A literature review is written in essay format. It is not an annotated bibliography, because it groups related works together and discusses trends and developments rather than focusing on one item at a time. It is not a summary; rather, it evaluates previous and current research in regard to how relevant and/or useful it is and how it relates to your own research.A Literature Review is more than an Annotated Bibliography or a summary, because you are organizing and presenting your sources in terms of their overall relationship to your own project.PurposeA literature review is written to highlight specific arguments and ideas in a field of study. By highlighting these arguments, the writer attempts to show what has been studied in the field, and also where the weaknesses, gaps, or areas needing further study are. The review should therefore also demonstrate to the reader why the writer’s research is useful, necessary, important, and valid.AudienceLiterature reviews can have different types of audiences, so consider why and for whom you are writing your review. For example, a lot of literature reviews are written as a chapter for a thesis or dissertation, so the audience will want to know in what way your research is important and original. Highlighting the gap in knowledge which your research aims to fill is particularly important in this instance because you need to convince the reader that there is an opening in the area of study. A literature review in a proposal will similarly try to convince the audience of the significance and worthiness of the proposed project. In contrast, when you are writing a literature review for a course, your professor may want you to show that you understand what research has been done,giving you a base of knowledge. In this case, you may not need to focus as much on proving where the gaps in knowledge lie, but rather, that you know what the major areas of study and key ideas are.Questions a Literature Review Should Answer:Asking questions such as the following will help you sift through your sources and organize your literature review. Remember, the literature review organizes the previous research in the light of what you are planning to do in your own project.∙What's been done in this topic area to date? What are the significant discoveries, key concepts, arguments, and/or theories that scholars have putforward? Which are the important works?∙On which particular areas of the topic has previous research concentrated?Have there been developments over time? What methodologies have been used? ∙Are there any gaps in the research? Are there areas that haven't been looked at closely yet, but which should be? Are there new ways of looking at the topic?∙Are there improved methodologies for researching this subject?∙What future directions should research in this subject take?∙How will your research build on or depart from current and previous research on the topic? What contribution will your research make to the field?LengthThe length of a literature review varies depending on its purpose and audience. In a thesis or dissertation, the review is usually a full chapter (at least 20 pages), but for an assignment it may only be a few pages.StructureThere are several ways to organize and structure a literature review. Two common ways are chronologically and thematically.Chronological:In a chronological review, you will group and discuss your sources in order of their appearance (usually publication), highlighting thechanges in research in the field and your specific topic over time. This method is useful for papers focusing on research methodology, historiographical papers, and other writing where time becomes an important element. For example, a literature review on theories of mental illness might present how the understanding of mental illness has changed through the centuries, by giving a series of examples of key developments and ending with current theories and the direction your research will take.Thematic:In a thematic review, you will group and discuss your sources in terms of the themes or topics they cover. This method is often a stronger one organizationally, and it can help you resist the urge to summarize your sources. By grouping themes or topics of research together, you will be able to demonstrate the types of topics that are important to your research. For example, if the topic of the literature review is changes in popular music, then there might be separate sections on research involving the production of music, research on the dissemination of music, research on the interpretation of music, and historical studies of popular music.No matter which method you choose, remember:Within each section of a literature review, it is important to discuss how the research relates to other studies (how is it similar or different, what other studies have been done, etc.) as well as to demonstrate how it relates to your own work. This is what the review is for: don’t leave this connection out!。

两层次中介检验MPLUS代码

两层次中介检验MPLUS代码

Mplus syntax files for single- and multilevel mediation models, to accompany: Preacher, K. J., Zyphur, M. J., & Zhang, Z. (2010). A general multilevel SEM framework for assessing multilevel mediation. Psychological Methods, 15, 209-233.Preacher, K. J., Zhang, Z., & Zyphur, M. J. (2011). Alternative methods for assessing mediation in multilevel data: The advantages of multilevel SEM. Structural Equation Modeling, 18, 161-182.Note: In models in which the Between and Within components of a 1→1 path are estimated separately and the Within component is random, the Between component is estimated as the contextual effect rather than as the Between slope in Mplus (see Mplus User's Guide, Ex.9.2). In Examples F and J this has been addressed by adding the Within slope to the contextual effect to yield the correct Between slope component before computing the indirect effect.A. simple mediationTITLE: simple mediationDATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREx m y;USEVARIABLES AREx m y;ANALYSIS: BOOTSTRAP IS 5000; ! bootstrap is recommended for simple mediation MODEL: ! model specification followsm ON x; ! regress mediator on independent variabley ON x m; ! regress outcome on both mediator and independent variableMODEL INDIRECT: ! request significance test for indirect effect of x on y via my IND m x; ! indirect effect of interest (ending in y and starting with x)OUTPUT: CINTERVAL(BCBOOTSTRAP); ! request bias-corrected bootstrap ! confidence intervalsB. 2-2-1 model with latent variables (MSEM)TITLE: 2-2-1 mediation (similar code used in example 2)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREgroup x1 x2 x3 m1 m2 m3 m4 m5 y1 y2 y3 y4 y5;MISSING ARE *; ! missing data denoted "*" in mydata.datUSEVARIABLES AREgroup x1 x2 x3 m1 m2 m3 m4 m5 y1 y2 y3 y4 y5;BETWEEN ARE x1 x2 x3 m1 m2 m3 m4 m5; ! identify variables with only Between variance; ! variables that are not claimed as "BETWEEN ARE" or "WITHIN ARE" can have! both Within and Between varianceCLUSTER IS group; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM; ! tell Mplus to perform multilevel modelingMODEL: ! model specification follows%WITHIN% ! Model for Within effects followsyw BY y1 y2 y3 y4 y5; ! yw is a factor defined by y1, y2, y3, y4, and y5%BETWEEN% ! Model for Between effects followsmb BY m1 m2 m3 m4 m5; ! mb is a factor defined by m1, m2, m3, m4, and m5xb BY x1 x2 x3; ! xb is a factor defined by x1, x2, and x3yb BY y1 y2 y3 y4 y5; ! yb is a factor defined by y1, y2, y3, y4, and y5mb ON xb(a); ! regress mb on xb, call the slope "a"yb ON mb(b); ! regress yb on mb, call the slope "b"yb ON xb; ! regress yb on xb, tooMODEL CONSTRAINT: ! section for computing indirect effectNEW(ab); ! name the indirect effectab = a*b; ! compute the indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsC. 2-1-1 model (traditional MLM)TITLE: 2-1-1 mediation (traditional MLM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREgroup x m y;USEVARIABLES AREgroup x m y;BETWEEN IS x; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN IS" or "WITHIN IS" can have! both Within and Between varianceCLUSTER IS group; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsm y; ! estimate Level-1 (residual) variances for m and yy ON m(b); ! regress y on m, call the slope "b"%BETWEEN% ! Model for Between effects followsx m y; ! estimate Level-2 (residual) variances for x, m, and ym ON x(a); ! regress m on x, call the slope "a"y ON m(b); ! regress y on m, constrain the slope equal to "b"y ON x; ! regress y on xMODEL CONSTRAINT: ! section for computing indirect effectNEW(indb); ! name the indirect effectindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsD. 2-1-1 model (unconflated MLM)TITLE: 2-1-1 mediation (unconflated MLM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREgroup x m y mmean;USEVARIABLES AREgroup x m y mmean;BETWEEN ARE x mmean; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN ARE" or "WITHIN ARE" can have ! both Within and Between varianceWITHIN ARE m; ! identify variables with only Within varianceCENTERING IS GROUPMEAN(m); ! group-mean center mCLUSTER IS group; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsm y; ! estimate Level-1 (residual) variances for m and yy ON m; ! regress y on m[m@0]; ! m was group-mean centered, so fix its mean to zero%BETWEEN% ! Model for Between effects followsy mmean; ! estimate Level-2 (residual) variances for y and mmeanmmean ON x(a); ! regress mmean on x, call the slope "a"y ON mmean(b); ! regress y on mmean, call the slope "b"y ON x; ! regress y on xMODEL CONSTRAINT: ! section for computing indirect effectNEW(indb); ! name the indirect effectindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsE. 2-1-1 model (MSEM)TITLE: 2-1-1 mediation (MSEM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREgroup x m y;USEVARIABLES AREgroup x m y;BETWEEN IS x; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN IS" or "WITHIN IS" can have! both Within and Between varianceCLUSTER IS group; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsm y; ! estimate Level-1 (residual) variances for m and yy ON m; ! regress y on m%BETWEEN% ! Model for Between effects followsx m y; ! estimate Level-2 (residual) variances for x, m, and ym ON x(a); ! regress m on x, call the slope "a"y ON m(b); ! regress y on m, call the slope "b"y ON x; ! regress y on xMODEL CONSTRAINT: ! section for computing indirect effectNEW(indb); ! name the indirect effectindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsF. 2-1-1 model with random slopes (MSEM)TITLE: 2-1-1 mediation (MSEM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREgroup x m y;USEVARIABLES AREgroup x m y;BETWEEN IS x; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN IS" or "WITHIN IS" can have! both Within and Between varianceCLUSTER IS group; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsm y; ! estimate Level-1 (residual) variances for m and ysb | y ON m; ! regress y on m%BETWEEN% ! Model for Between effects followsx m y; ! estimate Level-2 (residual) variances for x, m, and ym ON x(a); ! regress m on x, call the slope "a"y ON m(bb); ! regress y on m, call the slope "bb"; bb = contextual effect, not the Between slope y ON x; ! regress y on xsb WITH x m y; ! estimate Level-2 covariances of sb with x, m, and y[sb](bw); ! estimate the mean of sb, call it "bw"MODEL CONSTRAINT: ! section for computing indirect effectNEW(b indb); ! name the Between b path and the indirect effectb=bb+bw; ! compute Between b pathindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsG. 1-1-1 model (traditional MLM)TITLE: 1-1-1 mediation (traditional MLM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREid x m y;USEVARIABLES AREid x m y;CLUSTER IS id; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followssa | m ON x; ! regress m on x, call the random slope "sa"sb | y ON m; ! regress y on m, call the random slope "sb"sc | y ON x; ! regress y on x, call the random slope "sc"%BETWEEN% ! Model for Between effects followssa sb sc m y; ! estimate Level-2 (residual) variances for sa, sb, sc, m, and y[sa](a); ! estimate the mean of sa, call it "a"[sb](b); ! estimate the mean of sb, call it "b"sa WITH sc m y; ! estimate Level-2 covariances of sa with sc, m, and ysb WITH sc m y; ! estimate Level-2 covariances of sb with sc, m, and ysc WITH m y; ! estimate Level-2 covariances of sc with m and yy WITH m; ! estimate Level-2 covariance of y and msa WITH sb(cab); ! estimate Level-2 covariance of sa and sb, call it "cab"MODEL CONSTRAINT: ! section for computing indirect effectNEW(ind); ! name the indirect effectind=a*b+cab; ! compute the indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsH. 1-1-1 model (unconflated MLM)TITLE: 1-1-1 mediation (unconflated MLM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES ARE id x m y xmean mmean ymean;USEVARIABLES ARE id x m y xmean mmean;CENTERING IS GROUPMEAN(x m); ! group-mean center x and mCLUSTER IS id; ! Level-2 grouping identifierWITHIN ARE x m; ! identify variables with only Within variance;! variables that are not claimed as "BETWEEN ARE" or "WITHIN ARE" can have ! both Within and Between varianceBETWEEN ARE xmean mmean; ! identify variables with only Between variance ANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsm ON x(aw); ! regress m on x, call the slope "aw"y ON m(bw); ! regress y on m, call the slope "bw"y ON x; ! regress y on x[m@0]; ! m was group-mean centered, so fix its mean to zero%BETWEEN% ! Model for Between effects followsmmean y; ! estimate Level-2 (residual) variances for mmean and ymmean ON xmean (ab); ! regress mmean on xmean, call the slope "ab"y ON mmean (bb); ! regress y on mmean, call the slope "bb"y ON xmean; ! regress y on xmeanMODEL CONSTRAINT: ! section for computing indirect effectsNEW(indb indw); ! name the indirect effectsindw=aw*bw; ! compute the Within indirect effectindb=ab*bb; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsI. 1-1-1 model with fixed slopes (MSEM)TITLE: 1-1-1 mediation (MSEM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREid x m y;USEVARIABLES AREid x m y;CLUSTER IS id; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsm ON x(aw); ! regress m on x, call the slope "aw"y ON m(bw); ! regress y on m, call the slope "bw"y ON x; ! regress y on x%BETWEEN% ! Model for Between effects followsx m y; ! estimate Level-2 (residual) variances for x, m, and ym ON x(ab); ! regress m on x, call the slope "ab"y ON m(bb); ! regress y on m, call the slope "bb"y ON x; ! regress y on xMODEL CONSTRAINT: ! section for computing indirect effectsNEW(indb indw); ! name the indirect effectsindw=aw*bw; ! compute the Within indirect effectindb=ab*bb; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsJ. 1-1-1 model with random slopes (MSEM)TITLE: 1-1-1 mediation (MSEM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREid x m y;USEVARIABLES AREid x m y;CLUSTER IS id; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followssa | m ON x; ! regress m on x, call the random slope "sa"sb | y ON m; ! regress y on m, call the random slope "sb"sc | y ON x; ! regress y on x, call the random slope "sc"%BETWEEN% ! Model for Between effects followssa sb sc x m y; ! estimate Level-2 (residual) variances for sa, sb, sc, x, m, and ysa WITH sc x m y; ! estimate Level-2 covariances of sa with sc, x, m, and ysa WITH sb(cab); ! estimate Level-2 covariance of sa and sb, call it "cab"sb WITH sc x m y; ! estimate Level-2 covariances of sb with sc, x, m, and ysc WITH x m y; ! estimate Level-2 covariances of sc with x, m, and ym ON x(ab); ! regress m on x, call the slope "ab"; ab = contextual effect, not the Between slope y ON m(bb); ! regress y on m, call the slope "bb"; bb = contextual effect, not the Betweeen slope y ON x; ! regress y on x[sa](aw); ! estimate the mean of sa, call it "aw"[sb](bw); ! estimate the mean of sb, call it "bw"MODEL CONSTRAINT: ! section for computing indirect effectsNEW(a b indb indw); ! name the indirect effectsa=aw+ab; ! compute Between a pathb=bw+bb; ! compute Between b pathindw=aw*bw+cab; ! compute the Within indirect effectindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsK. 2-1-2 model (MSEM)TITLE: 2-1-2 mediation (MSEM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREid x m y;USEVARIABLES AREid x m y;CLUSTER IS id; ! Level-2 grouping identifierBETWEEN ARE x y; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN ARE" or "WITHIN ARE" can have ! both Within and Between varianceANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsm; ! estimate Level-1 (residual) variance for m%BETWEEN% ! Model for Between effects followsx y; ! estimate Level-2 (residual) variances for x and ym ON x(a); ! regress m on x, call the slope "a"y ON m(b); ! regress y on m, call the slope "b"y ON x; ! regress y on xMODEL CONSTRAINT: ! section for computing indirect effectNEW(indb); ! name the indirect effectindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsL. 1-2-1 model (MSEM)TITLE: 1-2-1 mediation (MSEM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES ARE id x m y;USEVARIABLES ARE id x y m;CLUSTER IS id; ! Level-2 grouping identifierBETWEEN ARE m; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN ARE" or "WITHIN ARE" can have ! both Within and Between varianceANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsy ON x; ! regress y on x%BETWEEN% ! Model for Between effects followsx m y; ! estimate Level-2 (residual) variances for x, m, and ym ON x(a); ! regress m on x, call the slope "a"y ON m(b); ! regress y on m, call the slope "b"y ON x; ! regress y on xMODEL CONSTRAINT: ! section for computing indirect effectNEW(indb); ! name the indirect effectindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsM. 1-2-2 model (MSEM)TITLE: 1-2-2 mediation (MSEM)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES ARE id x m y;USEVARIABLES ARE id x m y;CLUSTER IS id; ! Level-2 grouping identifierBETWEEN ARE m y; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN ARE" or "WITHIN ARE" can have ! both Within and Between varianceANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsx; ! estimate Level-1 (residual) variance for x%BETWEEN% ! Model for Between effects followsm y; ! estimate Level-2 (residual) variances for m and ym ON x(a); ! regress m on x, call the slope "a"y ON m(b); ! regress y on m, call the slope "b"y ON x; ! regress y on xMODEL CONSTRAINT: ! section for computing indirect effectNEW(indb); ! name the indirect effectindb=a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsN. 1-1-2 model with latent variables (MSEM)TITLE: 1-1-2 mediation (similar code used in example 3)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREgroup x1 x2 x3 x4 m1 m2 m3 y1 y2 y3 y4 y5;MISSING ARE *; ! missing data denoted "*" in mydata.datUSEVARIABLES AREgroup x1 x2 x3 x4 m1 m2 m3 y1 y2 y3 y4 y5;BETWEEN ARE y1 y2 y3 y4 y5; ! identify variables with only Between variance;! variables that are not claimed as "BETWEEN ARE" or "WITHIN ARE" can have ! both Within and Between varianceCLUSTER IS group; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsmw BY m1 m2 m3; ! mw is a factor defined by m1, m2, and m3xw BY x1 x2 x3 x4; ! xw is a factor defined by x1, x2, x3, and x4mw ON xw; ! regress mw on xw%BETWEEN% ! Model for Between effects followsmb BY m1 m2 m3; ! mb is a factor defined by m1, m2, and m3xb BY x1 x2 x3 x4; ! xb is a factor defined by x1, x2, x3, and x4yb BY y1 y2 y3 y4 y5; ! yb is a factor defined by y1, y2, y3, y4, and y5yb ON mb(b); ! regress yb on mb, call the slope "b"yb ON xb; ! regress yb on xbmb ON xb(a); ! regress mb on xb, call the slope "a"MODEL CONSTRAINT: ! section for computing indirect effectNEW(ab); ! name the indirect effectab = a*b; ! compute the Between indirect effectOUTPUT: TECH1 TECH8 CINTERVAL; ! request parameter specifications, starting values, ! optimization history, and confidence intervals for all effectsO. 1-(1,1)-1 model with one random slope (MSEM)TITLE: 1-(1,1)-1 mediation (similar code used in example 1)DATA: FILE IS mydata.dat; ! text file containing raw data in long formatVARIABLE: NAMES AREgroup x m1 m2 y;MISSING ARE ALL (-999); ! missing data denoted "-999" in mydata.dat USEVARIABLES AREgroup x m1 m2 y;CLUSTER IS group; ! Level-2 grouping identifierANALYSIS: TYPE IS TWOLEVEL RANDOM;MODEL: ! model specification follows%WITHIN% ! Model for Within effects followsy ON m1(bw1); ! regress y on m1, call the slope "bw1"y ON m2(bw2); ! regress y on m2, call the slope "bw2"c | y ON x; ! regress y on x, call the random slope "c"m1 WITH m2; ! estimate Level-1 residual covariance of m1 and m2m1 ON x(aw1); ! regress m1 on x, call the slope "aw1"m2 ON x(aw2); ! regress m2 on x, call the slope "aw2"%BETWEEN% ! Model for Between effects followsc m1 m2 y; ! estimate Level-2 (residual) variances for c, m1, m2, and yc WITH m1 m2 y; ! estimate Level-2 (residual) covariances of c with m1, m2, and yy ON m1(bb1); ! regress y on m1, call the slope "bb1"y ON m2(bb2); ! regress y on m2, call the slope "bb2"y ON x; ! regress y on x; this is the contextual effect, not the Between slopem1 WITH m2; ! estimate Level-2 residual covariance of m1 and m2m1 ON x(ab1); ! regress m1 on x, call the slope "ab1"m2 ON x(ab2); ! regress m2 on x, call the slope "ab2"[c]; ! estimate the mean of cMODEL CONSTRAINT: ! section for computing indirect effects and contrastsNEW(abw1 abw2 abb1 abb2 conw conb); ! name the indirect effects and contrastsabw1 = aw1*bw1; ! compute the first Within indirect effectabw2 = aw2*bw2; ! compute the second Within indirect effectabb1 = ab1*bb1; ! compute the first Between indirect effectabb2 = ab2*bb2; ! compute the second Between indirect effectUpdated 08/13/11 11 conw = abw1-abw2; ! compute the contrast of the Within indirect effectsconb = abb1-abb2; ! compute the contrast of the Between indirect effectsOUTPUT: TECH1 TECH8; ! request parameter specifications, starting values, and ! optimization history。

计算机科学外文原版图书目录:

计算机科学外文原版图书目录:

计算机科学外文原版图书目录:Innovations in Robot Mobility and Control机器人灵活性与控制的革新Machine Learning and Robot Perception机器学习与机器人的感知Modelling and Optimization of Biotechnological Processes生物技术过程的建模与最优化:人工智能方法Advances in Multiresolution for Geometric Modelling几何建模的多分辨率进展Agent-based Modeling Meets Gaming Simulation基于主体的建模与博奕模拟相遇Algebraic Aspects of the Advanced Encryption Standard先进加密标准的代数方面Algebraic Geometry and Geometric Modeling代数几何学与几何建模All of Nonparametric Statistics 非参数统计大全An Annotated Timeline of Operations Research运筹学注解时限Classification —the Ubiquitous Challenge分类—随处存在的挑战Classification Algorithms for Codes and Designs代码与设计用分类算法Combinatorial Optimization in Communication Networks通信网络中的组合最优化Communication SystemsComponent Models and Systems for Grid Applications格应用的组件模型与系统会议录Computational Electromagnetics计算电磁学Computer Vision Beyond the Visible Spectrum可见光谱以外的计算机视觉Condition Monitoring and Control for Intelligent Manufacturing智能制造用状态监控Constraint Theory约束理论:多维数学模型管理Constraint-Based Verification基于约束的验证Continuous System Simulation连续系统模拟Control of Traffic Systems in Buildings建筑物中的运输系统控制:现代监视与最佳控制应用Coordinated Multiuser Communications协同多用户通信Data Quality数据质量:概念、方法论与技术Design and Performance of 3G Wireless Networks and Wireless Lans3G 无线网络与无线局域网的设计与性能Design of Embedded Control Systems嵌入式控制系统的设计Digital Economy and Social DesignDigital Economy and Social Design数字经济与社会设计E-government and Public Sector Process Rebuilding电子政务与公共部门过程重建E-Merging Media电子融合媒体Enabling Semantic Web Services促进语义网服务Enabling Technologies for Wireless E-Business无线电子商务用促动技术Engineering and Managing Software Requirements工程与管理软件要求Enterprise Collaboration 企业协作Enterprise Knowledge Infrastructures企业知识基础结构Enterprise Ontology企业本体结构分析:理论与方法学Enterprise Service Oriented ArchitecturesEnterprise Service Oriented Architectures面向企业服务的体系结构:概念、挑战、建议Essential Software Architecture基本软件架构Evolutionary Computation for Modeling and Optimization建模与优化的演化计算Formal Modelling in Electronic CommerceFormal Modelling in Electronic Commerce电子商务的形式建模Form-Oriented Analysis面向格式的分析:基于格式的应用建模新方法Free Convection Film Flows and Heat Transfer 自由对流薄膜流与传热Free Convection Film Flows and Heat Transfer自由对流薄膜流与传热Handbook on Quality and Standardisation in E-LearningHandbook on Quality and Standardisation in E-Learning电子商务中质量与标准化手册Inference in Hidden Markov Models隐马尔可夫模型中的推论Information and Communication Technologies in Tourism 2005Information and Communication Technologies in Tourism 2005旅游业的信息与通信技术2005会议录Information Technology AuditingInformation Technology Auditing信息技术审计:发展中的议程Innovations in Robot Mobility and Control机器人灵活性与控制的革新Integrated Information Management综合信息管理:成功产业概念在IT中的应用Intelligence and Security Informatics for International Security国际安全用智能与安全信息学:信息综合与数据挖掘Intelligent Algorithms in Ambient and Biomedical Computing生物医学计算中的智能算法Interorganisational Standards跨组织标准:柔性供应链用Web服务规格的管理Lattice Boltzmann Modeling点阵玻尔兹曼建模Mathematical Methods and Modelling in Hydrocarbon Exploration and Production烃类勘探与生产的数学方法和建模Mathematical Problems in Image Processing图像处理中的数学问题Medical Informatics医学信息学:生物医学中的知识管理与数据挖掘Metaheuristics for Hard OptimizationMetaheuristics for Hard Optimization超启发式优化方法与案例研究Metaheuristics for Hard Optimization超启发式优化:方法与案例研究Modeling and Simulation in Scilab Scicos基于ScilabScicos的建模与仿真Modeling and Simulation Tools for Emerging Telecommunication Networks电信网络用建模与仿真工具New Algorithms for Macromolecular Simulation大分子模拟的新算法New Developments in Parsing Technology句法分析技术新发展Numerical Optimization数值优化:理论与实践方面Numerical Solution of Partial Differential Equations on Parallel Computers并行计算机上的偏微分方程的数值解Optical Communication Theory and Techniques光通信理论与技术Optimized Bayesian Dynamic Advising优化贝叶斯动态咨询:理论与算法Routine Human-Competitive Machine Intelligence例行与人竞争的机器智能Search Methodologies搜索方法论:优化与判定支持技术Statistical and Inductive Inference by Minimum Message Length最小信息长度的统计与归纳推理Stochastic Ageing and Dependence for Reliability用于决策可靠性的随机老化与依赖The Core Test Wrapper HandbookIEEE 1500标准手册The Economics of Online Markets and ICT Networks在线市场与ICT网络经济学Theoretical and Experimental DNA Computation理论与实验DNA计算。

图书馆绩效模糊综合评价模型研究

图书馆绩效模糊综合评价模型研究

年第6期总第期&信息决策(下半月刊)图书馆绩效模糊综合评价模型研究□李昌彩摘要本文简述了模糊综合评价理论,并就图书馆绩效模糊综合评价模型进行了研究。

关键词图书馆绩效评价模糊综合评判模型中图分类号:G258.6文献标识码:A服务质量的好坏是衡量图书馆办馆水平的重要标志之一,对图书馆的服务质量进行评价,通过部室之间服务质量的评价评定先进部室,以促进提高图书馆的整体服务水平,这也是图书馆每年必做的工作,在对服务质量的评价过程中,大量存在着内涵和外延都不分明、且处于运动变化发展中的动态模糊现象或动态模糊概念。

在图书馆实际评价中,人们往往忽视了这种动态模糊性,或只考虑其模糊性而未考虑其动态性。

到目前为至,还未见动态模糊综合评价的实例。

一、模糊综合评判法简述模糊数学中的模糊综合评判方法,是对具有多种属性的事物整体优劣进行评判,或者说某事物总体优劣受多种因素影响,难以直接用准确的定性语言进行评估时,可以考虑一种能合理地综合这些属性或因素的整体评判方法。

运用此方法对原本仅具有模糊和非定量化特征的因素,经过某种数学处理,通过使用模糊集合来工作的,使其具有某种量化的表达形式,是一种解决不完全、主观化信息的评估方法,其最大特点就是用它可以处理人类思维的主动性和模糊性。

为决策提供可以进行比较和判别的依据,从而提高决策的科学性和正确性。

用模糊综合评判方法所得出的结果,既可直接反馈给馆员用于改进工作,也可作为图书馆领导决策的依据,并为最终决策提供参考。

二、动态模糊综合评价的理论(一)动态模糊集。

动态模糊集简称DFS (Dynamic Fuzzy Sets )是表示动态模糊数据的一种方法,它是模糊集合(FS )理论的推广:在模糊集合中,考虑了数据的模糊性,定义元素对集合A 的隶属度已从经典集合的0或1这两个值扩充为[0,1],但FS 反映的公是静态的模糊数据,对具体动态模糊性的数据依然无法表达。

如果在模糊集合理论的基础上,再考虑数据的动态变化性。

参考文献(人工智能)

参考文献(人工智能)

参考文献(人工智能)曹晖目的:对参考文献整理(包括摘要、读书笔记等),方便以后的使用。

分类:粗分为论文(paper)、教程(tutorial)和文摘(digest)。

0介绍 (1)1系统与综述 (1)2神经网络 (2)3机器学习 (2)3.1联合训练的有效性和可用性分析 (2)3.2文本学习工作的引导 (2)3.3★采用机器学习技术来构造受限领域搜索引擎 (3)3.4联合训练来合并标识数据与未标识数据 (5)3.5在超文本学习中应用统计和关系方法 (5)3.6在关系领域发现测试集合规律性 (6)3.7网页挖掘的一阶学习 (6)3.8从多语种文本数据库中学习单语种语言模型 (6)3.9从因特网中学习以构造知识库 (7)3.10未标识数据在有指导学习中的角色 (8)3.11使用增强学习来有效爬行网页 (8)3.12★文本学习和相关智能A GENTS:综述 (9)3.13★新事件检测和跟踪的学习方法 (15)3.14★信息检索中的机器学习——神经网络,符号学习和遗传算法 (15)3.15用NLP来对用户特征进行机器学习 (15)4模式识别 (16)4.1JA VA中的模式处理 (16)0介绍1系统与综述2神经网络3机器学习3.1 联合训练的有效性和可用性分析标题:Analyzing the Effectiveness and Applicability of Co-training链接:Papers 论文集\AI 人工智能\Machine Learning 机器学习\Analyzing the Effectiveness and Applicability of Co-training.ps作者:Kamal Nigam, Rayid Ghani备注:Kamal Nigam (School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, knigam@)Rayid Ghani (School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213 rayid@)摘要:Recently there has been significant interest in supervised learning algorithms that combine labeled and unlabeled data for text learning tasks. The co-training setting [1] applies todatasets that have a natural separation of their features into two disjoint sets. We demonstrate that when learning from labeled and unlabeled data, algorithms explicitly leveraging a natural independent split of the features outperform algorithms that do not. When a natural split does not exist, co-training algorithms that manufacture a feature split may out-perform algorithms not using a split. These results help explain why co-training algorithms are both discriminativein nature and robust to the assumptions of their embedded classifiers.3.2 文本学习工作的引导标题:Bootstrapping for Text Learning Tasks链接:Papers 论文集\AI 人工智能\Machine Learning 机器学习\Bootstrap for Text Learning Tasks.ps作者:Rosie Jones, Andrew McCallum, Kamal Nigam, Ellen Riloff备注:Rosie Jones (rosie@, 1 School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213)Andrew McCallum (mccallum@, 2 Just Research, 4616 Henry Street, Pittsburgh, PA 15213)Kamal Nigam (knigam@)Ellen Riloff (riloff@, Department of Computer Science, University of Utah, Salt Lake City, UT 84112)摘要:When applying text learning algorithms to complex tasks, it is tedious and expensive to hand-label the large amounts of training data necessary for good performance. This paper presents bootstrapping as an alternative approach to learning from large sets of labeled data. Instead of a large quantity of labeled data, this paper advocates using a small amount of seed information and alarge collection of easily-obtained unlabeled data. Bootstrapping initializes a learner with the seed information; it then iterates, applying the learner to calculate labels for the unlabeled data, and incorporating some of these labels into the training input for the learner. Two case studies of this approach are presented. Bootstrapping for information extraction provides 76% precision for a 250-word dictionary for extracting locations from web pages, when starting with just a few seed locations. Bootstrapping a text classifier from a few keywords per class and a class hierarchy provides accuracy of 66%, a level close to human agreement, when placing computer science research papers into a topic hierarchy. The success of these two examples argues for the strength of the general bootstrapping approach for text learning tasks.3.3 ★采用机器学习技术来构造受限领域搜索引擎标题:Building Domain-specific Search Engines with Machine Learning Techniques链接:Papers 论文集\AI 人工智能\Machine Learning 机器学习\Building Domain-Specific Search Engines with Machine Learning Techniques.ps作者:Andrew McCallum, Kamal Nigam, Jason Rennie, Kristie Seymore备注:Andrew McCallum (mccallum@ , Just Research, 4616 Henry Street Pittsburgh, PA 15213)Kamal Nigam (knigam@ , School of Computer Science, Carnegie Mellon University Pittsburgh, PA 15213)Jason Rennie (jr6b@)Kristie Seymore (kseymore@)摘要:Domain-specific search engines are growing in popularity because they offer increased accuracy and extra functionality not possible with the general, Web-wide search engines. For example, allows complex queries by age-group, size, location and cost over summer camps. Unfortunately these domain-specific search engines are difficult and time-consuming to maintain. This paper proposes the use of machine learning techniques to greatly automate the creation and maintenance of domain-specific search engines. We describe new research in reinforcement learning, information extraction and text classification that enables efficient spidering, identifying informative text segments, and populating topic hierarchies. Using these techniques, we have built a demonstration system: a search engine forcomputer science research papers. It already contains over 50,000 papers and is publicly available at ....采用多项Naive Bayes 文本分类模型。

自-各种计算电磁学方法比较

自-各种计算电磁学方法比较

微波EDA仿真软件与电磁场的数值算法密切相关,在介绍微波EDA软件之前先简要的介绍一下微波电磁场理论的数值算法。

所有的数值算法都是建立在Maxwell方程组之上的,了解Maxwe ll方程是学习电磁场数值算法的基础。

计算电磁学中有众多不同的演法,如时域有限差分法(FDTD)、时域有限积分法(FITD)、有限元法(FE)、矩量法(MoM)、边界元法(BEM)、谱域法(SM)、传输线法(TLM)、模式匹配法(MM)、横向谐振法(TRM)、线方法(ML)和解析法等等。

在频域,数值算法有:有限元法(FEM -- FiniteElementMethod)、矩量法( MoM -- Method of Moments),差分法( FDM --Finite Difference Methods),边界元法(BEM--Boundary Element Method),和传输线法( TLM-- Transmission-Line-matrixM ethod)。

R+x在时域,数值演算法有:时域有限差分法(FDTD - FiniteDifferenceTime Domain ),和有限积分法(FIT-Finite Integration Technology)。

这些方法中有解析法、半解析法和数值方法。

数值方法中又分零阶、一阶、二阶和高阶方法。

依照解析程度由低到高排列,依次是:时域有限差分法(FDTD)、传输线法(TLM)、时域有限积分法(FITD)、有限元法(FEM)、矩量法(MoM)、线方法(ML)、边界元法(BEM)、谱域法(SM)、模式匹配法(MM)、横向谐振法(TRM)、和解析法。

依照结果的准确度由高到低,分别是:解析法、半解析法、数值方法。

在数值方法中,按照结果的准确度有高到低,分别是:高阶、二阶、一阶和零阶。

时域有限差分法(FDTD)、时域有限积分法(FITD)、有限元法(FEM)、矩量法(MoM)、传输线法(TLM)、线方法(ML)是纯粹的数值方法;边界元法(BEM)、谱域法(SM)、模式匹配法(MM)、横向谐振法(TRM)则均具有较高的解析度。

practical multilevel modeling using r pdf

practical multilevel modeling using r pdf

practical multilevel modeling using rpdfPractical Multilevel Modeling (MLM) using R is an essential tool for data scientists looking to gain a better understanding of their data. With the ability to generate predictions, evaluate trends and detect correlations, MLM can provide an invaluable tool to analyse large datasets in an efficient manner.MLM is a type of linear regression that takes into account the hierarchical structure of the data. It allows for multiple levels of analysis, such as individual-level variables, group-level variables and even cross-level variables. This makes it possible to examine how group-level variables influence individual-level behaviour. For example, in education research, MLM can be used to explore how school-level factors interact with learner-level behaviour.Using R to conduct multilevel analyses is relatively straightforward. First, it is important to understand the key concepts of MLM and obtain an overview of the dataset. The next step is to load the data into R and check for missing or invalid values and prepare the data for analysis. Then, the MLM model and its associated parameters must be specified and estimated, after which the results can be visualised and interpreted. Further, post hoc tests can be performed to further investigate the relationships between variables.In addition to the basic MLM, there are also several other extensions that can be employed to extract additionalinformation from the data. This includes mixed-effects models, which allow for both fixed and random effects to be includedin the analysis, and nonlinear mixed-effects models, whichcan be used to fit more complex and nonlinear models.MLM is an incredibly useful tool for data analysts andit offers a wealth of opportunities for better understandingof data. By using R, data scientists can easily access the capabilities of MLM, allowing them to unlock insights from large and complex datasets.。

关于系统辨识的英文书籍

关于系统辨识的英文书籍

系统辨识是一门研究如何从系统的输入和输出数据中推断系统内部动态特性的学科。

在工程领域中,系统辨识被广泛应用于控制、信号处理、预测等领域。

随着科技的发展,系统辨识的应用范围也在不断扩大。

为了更好地掌握系统辨识的知识和技能,许多经典的英文书籍被撰写出来,以帮助读者深入了解系统辨识的理论和实践。

以下是一些经典的书籍:1. 《System Identification: Theory for the User. 2nd Edition》by P. J. G. Ramadge and W. M. Wetherall。

这本书是系统辨识领域的经典之作,涵盖了系统辨识的基本理论和实践方法,包括最小二乘法、递归辨识算法、稳定性分析等内容。

2. 《System Identification: Parameter and State Estimation》by Freddy Lindell。

这本书主要介绍了参数估计和状态估计的方法,包括最小二乘法、极大似然估计、卡尔曼滤波器等。

书中还通过实例演示了如何应用这些方法进行系统辨识。

3. 《Identification of Parameters in Linear Dynamic Systems》by H. Hjalmarsson。

这本书专注于线性动态系统的参数辨识,介绍了最小二乘法和递归最小二乘法等参数估计方法,以及如何应用这些方法进行系统辨识。

4. 《System Identification with an Introduction to Experimental Data Analysis》by Yuriy V. Gaiarsa and Joseph T. Lizier。

这本书不仅介绍了系统辨识的基本理论和方法,还详细介绍了如何进行实验数据分析和处理,包括数据预处理、噪声抑制、数据平滑等内容。

5. 《System Identification: A Practical Guide for Engineers and Scientists》by Tore Hagglund and Mats Åström。

英文语言知识大模型评测集

英文语言知识大模型评测集

英文语言知识大模型评测集全文共四篇示例,供读者参考第一篇示例:英文语言知识大模型评测集在自然语言处理领域占据着重要的地位。

这种评测集可以帮助研究人员评估和比较不同模型的性能,促进模型的发展和改进。

在这篇文章中,我们将介绍一些常见的英文语言知识大模型评测集,并对其进行简要的评测和分析。

一、BERT评测集BERT(Bidirectional Encoder Representations from Transformers)是谷歌于2018年提出的一种预训练的语言模型。

为了评估BERT模型的性能,研究人员设计了一系列评测集,如GLUE (General Language Understanding Evaluation)和SQuAD (Stanford Question Answering Dataset)。

GLUE评测集包括一系列涵盖自然语言理解各个方面的任务,如句子对匹配、情感分析和自然语言推理等。

研究人员在GLUE评测集上评估了多种不同的预训练模型,在各项任务上取得了很好的表现。

SQuAD评测集是一个问答任务评测集,包含一系列关于阅读理解的问题和对应的答案。

研究人员使用SQuAD评测集来评估模型在理解自然语言方面的能力,BERT模型在SQuAD评测集上也取得了非常好的成绩。

二、GPT评测集其中一个常用的评测集是ROCStories,该评测集包含一系列具有逻辑关系的五个句子,要求模型生成合理的结局。

研究人员还设计了一些其他的文本生成任务,如句子填空和对话生成等,用来评估模型在不同生成任务上的表现。

除了文本生成任务,研究人员还设计了一些文本分类任务来评估GPT模型的分类能力。

通过在这些评测集上的表现,研究人员可以更全面地评估模型在自然语言处理方面的能力。

三、总结和展望英文语言知识大模型评测集在自然语言处理领域起着至关重要的作用,可以帮助研究人员评估和比较不同模型的性能,促进模型的发展和改进。

在未来,我们可以进一步扩展评测集的规模和多样性,设计更具挑战性的任务来测试模型的能力。

关于部分中介与完全中介作用(与课堂定义相同)

关于部分中介与完全中介作用(与课堂定义相同)

关于部分中介与完全中介作⽤(与课堂定义相同)http://203.208.35.101/search?q=cache:IERvvryqTfQJ:/doc/ae081e0476*******edb11d7.html/cm/mediate.htm+what+is+ partial+mediation&hl=zh-CN&ct=clnk&cd=6&gl=cn&st_usg=ALhdy28nm9ic9hiZ2WRtEodqzcd -ciATMw来源:google⽹页快照David A. KennyJanuary 10, 2008Please email me suggestions and corrections.MEDIATIONWhat is Mediation?Baron & Kenny StepsMeasuring Mediation or the Indirect Effect Design IssuesSpecification ErrorExtensionsLinks to Other SitesReferencesWhat Is Mediation?Consider a variable X that is assumed to affect another variableY. The variable X is called the initial variable and the variable that it causes or Y is called the outcome. In diagrammatic form, the unmediated model is图⽚显⽰不出来The effect of X on Y may be mediated by a process or mediating variable M, and the variable X may still affect Y. Path c is called the totaleffect. The mediated model is图⽚显⽰不出来(These two diagrams are essential to the understanding of thispage. Please study them carefully!) Path c' is called the directeffect. The mediator has been called an intervening or process variable. Complete mediation is the case in which variable X no longer affects Y after M has been controlled and so path c' is zero. Partial mediation is the case in which the path from X to Y is reduced in absolute size but is still different from zero when the mediator is controlled.Note that a mediational model is a causal model. For example, the mediator is presumed to cause the outcome and not vice versa. If the presumed model is not correct, the results from the mediational analysis are of little value. Mediation is not defined statistically; rather statistics can be used to evaluate a presumed mediational model. The reader should consult the section below on Specification Error.There is a long history in the study of mediation (Hyman, 1955; MacCorquodale & Meehl, 1948). Currently mediation is a very popular topic. (This page averages over 100 different visitors a day.) There are several reasons for the intense interest in this topic. One reason for testing mediation is trying to understand the mechanism through which the initial variable affects the outcome. Mediation (and moderation) analysis are a key part of what has been called processanalysis. Moreover when most causal or structural models are examined, the mediational part of the model is the most interesting.Baron and Kenny StepsIf the mediational model (see above) is correctly specified, the paths (c, a, b, and c') can be estimated by multiple regression, sometimes call ordinary least squares or OLS. As discussed later, other methods of estimation (e.g., logistic regression andstructural equal modeling) can be used. Regardless of which data analytic method (the general assumption on this page is that it is multiple regression) is used, the steps necessary for testing mediation are the same. This section describes the analyses required for testing mediational hypotheses [previously presented by Baron and Kenny (1986) and Judd and Kenny (1981)].Baron and Kenny (1986) and Judd and Kenny (1981) have discussed four steps in establishing mediation:Step 1:Show that the initial variable is correlated with theoutcome. Use Y as the criterion variable in a regression equation and X as a predictor (estimate and test path c). This step establishes that there is an effect that may be mediated.Step 2: Show that the initial variable is correlated with themediator. Use M as the criterion variable in the regressionequation and X as a predictor (estimate and test path a). This step essentially involves treating the mediator as if it were an outcomevariable.Step 3: Show that the mediator affects the outcomevariable. Use Y as the criterion variable in a regression equationand X and M as predictors (estimate and test path b). It is notsufficient just to correlate the mediator with the outcome; themediator and the outcome may be correlated because they areboth caused by the initial variable X. Thus, the initial variablemust be controlled in establishing the effect of the mediator on the outcome.Step 4: To establish that M completely mediates the X-Yrelationship, the effect of X on Y controlling for M (path c')shouldbe zero (see discussion on significance testing). The effects inboth Steps 3 and 4 are estimated in the same equation.If all four of these steps are met, then the data are consistent with the hypothesis that variable M completely mediates the X-Y relationship, and if the first three steps are met but the Step 4 is not, then partial mediation is indicated. Meeting these steps does not, however, conclusively establish that mediation has occurred because there are other (perhaps less plausible) models that are consistent with the data. Some of these models are considered later in the Specification Error section.Note that the steps are stated in terms of zero and nonzero coefficients, not in terms of statistical significance, as they were in Baron and Kenny (1986). Because trivially small coefficients can be statistically significant with large sample sizes and very large coefficients can be nonsignificant with small sample sizes, the steps should not be defined in terms of statistical significance. Statistical significance is informative, but other information should be part of statistical decision making. For instance, consider the case in which a is large, b is zero, and so c = c'. It is very possible that the statistical test of c' is not significant (due to the collinearity of X and M) whereas c is significant. It would then appear that there is complete mediation when if fact there is no mediation at all.Following, Kenny, Kashy, and Bolger (1998), one might ask whetherall of the steps have to be met for there to be mediation. Certainly, Step 4 does not have to be met unless the expectation is for complete mediation. In the opinion of most though not all analysts, Step 1 is notrequired. However, note that a path from the initial variable to the outcome is implied if Steps 2 and 3 are met. If c' were opposite in sign to ab something that MacKinnon, Fairchild, and Fritz (2007) refer to as "inconsistent mediation," then it could be the case that Step 1 would not be met, but there is still mediation. In this case the mediator acts like a suppressor variable. Most analysts believe that the essential steps in establishing mediation are Steps 2 and 3.James and Brett (1984) have argued that Step 3 should be modified by not controlling for the initial variable. Their rationale isthat if there is complete mediation, there would be no need to control for the initial variable. However, because complete mediation does not always occur, it would seem sensible to control for X in Step 3.Measuring Mediation or the IndirectEffectThe amount of mediation, which is called the indirect effect, is defined as the reduction of the effect of the initial variable on the outcome or c - c'. This difference in coefficients is theoretically exactly the same as the product of the effect of X on M times the effect of M on Y or ab; thus it holds that ab ≈ c - c'. The two are exactly equal when a) multiple regression (or structural equation modeling without latent variables) is used, b) there are no missing data, c) and the same covariates are in the equation. However, the two are only approximately equal for multilevel models, logistic analysis and structural equation model with latent variables. For such models, it is probably inadvisable to compute cfrom Step 1, but rather c should be inferred to be c' + ab and not directly computed. Note that the amount of reduction in the effect of X on Y is not equivalent to either the change in variance explained or the changein an inferential statistic such as F or a p value. It is possible for the F from the initial variable to the outcome to decrease dramatically even when the mediator has no effect on the outcome! It is also not equivalent to a change in partial correlations. If Step 2 (the test of a) and Step 3 (the test of b) are met, it follows that there necessarily is a reduction in the effect of X on Y. One way to test the null hypothesis that ab = 0 is to test that both a and b are zero (Steps 2 and 3). If such a strategy were used and one wanted a .05 probability of the combined test that a = 0 and b = 0, then alpha for the tests of a and b should lowered to .0253 so that the Type I error protection rate is correct.Much more commonly, a single test is used and is highly recommended (MacKinnon, Lockwood, Hoffman, West, & Sheets, 2002). The test was first proposed by Sobel (1982). It requires the standard error of a or s a (which equals a/t a where t a is the t test of coefficient a) and the standard error of b or s b. The Sobel test provides the standard error of ab can be shown to equal approximately the square root ofb2s a2 + a2s b2Other standard errors have been proposed, but the Sobel test is by far the most commonly reported. The test of the indirect effect is given by dividing ab by the square root of the above variance and treating the ratio as a Z test (i.e., larger than 1.96 in absolute value is significant at the .05 level). Kristopher J. Preacher and Geoffrey J. Leonardelli have an excellent web page that can help you calculate these test (go to the Sobel test). Measures and tests of indirect effects are also available within many structural equation modeling programs. These programs appear to use the Sobel formula.The derivation of the Sobel standard error presumes that a and b are independent, something that is true when the tests are from multiple regression but not true when other tests are used (e.g., logistic regression, structural equation modeling, and multilevel modeling). In such cases, the researcher ideally provides evidence for approximate independence. Additionally, the Sobel test can be conducted using the standardized or unstandardized coefficients. Care must be taken to use the appropriate standard errors if standardized coefficients are used.The Sobel test is very conservative (MacKinnon, Warsi, & Dwyer, 1995), and Dave MacKinnon and others are exploring more efficient testing methods. One such strategy is bootstrapping (Shrout & Bolger, 2002) which is beginning to replace the Sobel test of the indirect effect. One can use Amos to bootstrap click here for a tutorial).A related measure of mediation is the proportion of the effect that is mediated or 1 - ab/c. Such a measure while theoretically informative is very unstable and should not be computed is c is small. Note too that it can be greater than 1. The measure can be informative, especially when c' is not statistically significant. See the example in Kenny et al. (1998) where c' is not statistically significant but only 56% of c is explained.Design IssuesDistal and Proximal MediationTo demonstrate mediation both paths a and b need to be relatively large. Generally, the maximum size of the product ab is c, and so as path a increases, path b must decrease and vice versa.The mediator can be too close in time or in the process to the initial variable and so path a would be relatively large and path b relatively small. An example of a proximal mediator is a manipulation check. The use of a very proximal mediator creates multicollinearity which is discussed in the next section.Alternatively, the mediator can be chosen too close to the outcome and with a distal mediator path b is large and path a is small. Ideally in terms of power, standardized a and b should be comparable insize. Work by Hoyle and Kenny (1999) shows that the power of the test of ab is maximal when b is somewhat larger than a. So distal mediators result in somewhat greater power than proximal mediators.MulticollinearityIf M is a successful mediator, it is necessarily correlated with X due to path a. This correlation, called collinearity, affects the precision of the estimates of the last set of regression equations. If X were to explain all of the variance in M, then there would be no unique variance in M to explain Y. Given that a is nonzero, the power of the tests of the coefficients b and c' is compromised. The effective sample size for these tests is approximately N(1 - r2) where N is the total sample size and r is the correlation between the initial variable and the mediator. So if M is a strong mediator (path a is large), to achieve equivalent power the sample size would have to be larger than what it would be if M were a weak mediator. Multicollinearity is to be expected in a mediational analysis and it cannot be avoided.Specification ErrorMediation is a hypothesis about a causal network. (See Kraemer, Wilson, Fairburn, and Agras (2002) who attempt to define mediation without making causal assumptions). The conclusions from a mediation analysis are valid only if the causal assumptions are valid. In this section, the three major assumptions of mediation arediscussed. Mediation analysis makes all of the standard assumptions ofthe general linear model (i.e., linearity, normality, homogeneity of error variance, and independence of errors).Reverse Causal EffectsThe mediator may be caused by the outcome variable (Y would cause M in the above diagram). When the initial variable is a manipulated variable, it cannot be caused by either the mediator or the outcome. But because both the mediator and the outcome variables are not manipulated variables, they may cause each other.Often it is advisable to interchange the mediator and the outcome variable and have the outcome "cause" the mediator. If the results look similar to the specified mediational pattern (i.e., the c' and b are about the same in the two models), one would be less confident in the specified model.Sometimes reverse causal effects can be ruled out theoretically. That is, a causal effect in one direction does not make sense. Design considerations may also weaken the plausibility of reversecausation. Ideally, the mediator should be measured temporally before the outcome variable.If it can be assumed that c' is zero, then reverse causal effects can be estimated. That is, if it can be assumed that there is complete mediation (X does not directly cause Y and so c' is zero), the mediator may cause the outcome and the outcome may cause the mediator.Smith (1982) has developed another method for the estimation of reverse causal effects. Both the mediator and the outcome variables are treated as outcome variables, and they each may mediate the effect of the other. To be able to employ the Smith approach, for both the mediator and the outcome, there must be a different variable that is known to cause each of them but not the other. So a variable must be found that is known to cause the mediator but not the outcome and another variable that is known to cause the outcome but not the mediator. These variables are called instrumental variables. Thus, mediation can be estimated and tested with models of feedback. Measurement Error in the MediatorIf the mediator is measured with less than perfect reliability, then the effects (b and c') are likely biased. The effect of the mediator on theoutcome (path b) is likely underestimated and the effect of the initial variable on the outcome (path c') is likely over-estimated if ab is positive (which is typical). The over-estimation of c' is exacerbated to the extent to which path a is large.To remove the biasing effect of measurement error, multiple indicators of the mediator can be used to tap a latentvariable. Alternatively, instrumental variable estimation can be used, but as before, it must be assumed that c' is zero. Also possible is to fix the error variance at the value or one minus the reliability quantity times the variance of the measure. If none of these approaches is used, the researcher needs to demonstrate that the reliability of the mediator is very high so that the bias is fairly minimal.Omitted VariablesIn this case, there is a variable that causes both variables in the equation. For example, at Step 3, there is a variable that causes both the mediator and the outcome. This is the most difficult specification error to solve. Although there has beensome work on the omitted variable problem, the only complete solution is to specify and measure such variables and control for their effects. Note that if the initial variable is randomized, then omitted variables do not bias the estimates at Steps 1 and 2. Even, if X is manipulated, path c' is biased is there is an omitted variable that causes M and Y.Sometimes the source of correlation between the mediator and the outcome is a common method effect. For instance, the measuring scale of the two variables is the same. Ideally, efforts should be made to ensure that the two variables do not share method effects (e.g., both are self-reports from the same person). A latent variable analysis might be used to remove the effects of correlated measurement error.ExtensionsMediated Moderation and Moderated Mediation Moderation means that the effect of a variable on an outcome is altered (i.e., moderated) by another variable. Moderation is usually captured by an interaction of two initial variables. If this moderation is mediated, then we have the usual pattern of mediation but the X variable is an interaction and is referred to as mediated moderation.. (To readabout moderation click here.) All the Baron and Kenny steps would be repeated with the effect of Step 1 being an interaction, and the two main effects would be treated as "covariates."A variable may act as a mediator stronger for one group (e.g., males) than for another (e.g., females). There are two different forms of moderated mediation. The effect of the initial variable on the mediator may differ as a function of the moderator (i.e., path a varies) or the mediator may interact with the moderator to cause the outcome (i.e., path b varies). Note that interactions are commonly testing by computing a product term, but there are other ways to specify the interaction (e.g., absolute difference). Theory should inform the proper specification of the interaction.Papers by Muller, Judd, and Yzerbyt (2005) and Edwards and Lambert (2007) discuss the relationship between mediated moderation and moderated mediation. They also present examples of each.Multiple Mediators or OutcomesIf there are multiple mediators, they can be tested simultaneously or separately. The advantage of doing them simultaneously is that one learns if the mediation is independent of the effect of the other mediators. One should make sure that the different mediators are conceptually distinct and not too highly correlated. (Kenny, Kashy, and Bolger (1998) consider an example with two mediators.) There is an interesting case of two mediators in which ab is opposite sign. The sum of indirect effects would be near zero. It might then be possible that c is near zero, because there are two indirect effects that work in the opposite direction. In this case "no effect" would be mediated.If there are multiple outcomes, they can be test simultaneously or separately. If tested simultaneously, the entire model can be estimated by structural equation modeling.Latent VariablesIn this case the analysis would be done by a structural equation modeling program (e.g., LISREL, Amos, Eqs, or MPlus). Some programs provide measures and tests of indirect effects. Also such programs are quite flexible in handling multiple mediators and outcomes. The one complication is how to handle Step 1. That is, if two models are estimated, one with the mediator and one without, the paths c and c' arenot comparable because the factor loadings would be different. It is then inadvisable to test the relative fit of two structural models, one with the mediator and one without. Rather c can be estimated using the formula of c' + ab.CovariatesThere are often variables that do not change that can cause or be correlated with the initial variable, mediator, and outcome (e.g., age, gender, ethnicity); these variables are commonly calledcovariates. They would generally included in each equation and would not be trimmed from equations unless they are dropped from all of the equations.Dichotomous VariablesIn this case either the mediator or the outcome is adichotomy. Having the initial variable be a dichotomy is not problematic. In this case the analysis would likely be conducted using logistic regression when the criterion measure is dichotomous. One can still use the Baron and Kenny steps and the Sobel test. The one complication is the computation of indirect effect the degree of mediation, but coefficients need to be transformed. (To read about the computation of indirect effects click here.)Multilevel ModelingEstimation of mediation within multilevel models can be very complicated, especially when the mediation occurs at level one and when that mediation is allowed to be random, i.e., vary across level two units. The reader is referred to Krull and MacKinnon (1999), Kenny, Korchmaros, and Bolger (2003), and Bauer and Preacher (2006) for a discussion of this topic.Links to Other Sitesis wrong.A web-based Sobel test of the indirect effect or ab by Preacher and Leonardelli.ReferencesBaron, R. M., & Kenny, D. A. (1986). The moderator-mediator variable distinction in social psychological research: Conceptual, strategic and statistical considerations. Journal of Personality and Social Psychology, 51, 1173-1182. Bauer, D. J., Preacher, K. J., & Gil, K. M. (2006). Conceptualizing and testing random indirect effects and moderated mediation in multilevel models: New procedures and recommendations. Psychological Methods, 11, 142-163.Edwards, J. R., & Lambert L. S. (2007). Methods for integrating moderation and mediation: A general analytical framework using moderated path analysis. Psychological Methods, 12, 1-22.Hoyle, R. H., & Kenny, D. A. (1999). Statistical power and tests of mediation. In R. H. Hoyle (Ed.), Statistical strategies for small sample research. Newbury Park: Sage.Hyman, H. H. (1955). Survey design and analysis. New York: Glencoe, IL: The Free Press.James, L. R., & Brett, J. M. (1984). Mediators, moderators and tests for mediation. Journal of Applied Psychology, 69, 307-321.Judd, C. M., & Kenny, D. A. (1981). Process analysis: Estimating mediation in treatment evaluations. Evaluation Review, 5, 602-619. Kenny, D. A., Kashy, D. A., & Bolger, N. (1998). Data analysis in social psychology. In D. Gilbert, S. Fiske, & G. Lindzey (Eds.), The handbook of social psychology (Vol. 1, 4th ed., pp. 233-265). Boston,MA: McGraw-Hill.Kenny, D. A., Korchmaros, J. D., & Bolger, N. (2003). Lower level mediation in multilevel models. Psychological Methods, 8, 115-128. Kraemer H. C., Wilson G. T., Fairburn C. G., & Agras W.S. (2002). Mediators and moderators of treatment effects in randomized clinical trials. Archives of General Psychiatry, 59, 877-883.Krull, J. L. & MacKinnon, D. P. (1999). Multilevel mediation modeling in group-based intervention studies. Evaluation Review, 23, 418-444.MacCorquodale, K., & Meehl, P. E. (1948). On a distinction between hypothetical constructs and intervening variables. Psychological Review, 55, 95-107.MacKinnon, D. P., Fairchild, A. J., & Fritz, M. S. (2007). Mediation analysis. Annual Review of Psychology, 58,, 593-614.MacKinnon, D. P., Lockwood, C. M., Hoffman, J. M., West, S. G., & Sheets, V. (2002). A comparison of methods to test the significance of the mediated effect. Psychological Methods, 7, 83-104.MacKinnon, D. P., Warsi, G., & Dwyer, J. H. (1995). A simulation study of mediated effect measures. Multivariate Behavioral Research, 30,41-62.Muller, D., Judd, C. M., & Yzerbyt, V. Y. (2005). When moderation is mediated and mediation is moderated. Journal of Personality and Social Psychology, 89,, 852-863.Shrout, P. E., & Bolger, N. (2002). Mediation in experimental and nonexperimental studies: New procedures and recommendations. Psychological Methods, 7, 422-445.Smith, E. (1982). Beliefs, attributions, and evaluations: Nonhierarchical models of mediation in social cognition. Journal of Personality and Social Psychology, 43,248-259.Sobel, M. E. (1982). Asymptotic confidence intervals for indirect effects in structural equation models. In S. Leinhardt (Ed.), Sociological Methodology 1982 (pp. 290-312). Washington DC: American Sociological Association.。

矩量法中边界电荷对电流及近场分布的影响

矩量法中边界电荷对电流及近场分布的影响

矩量法中边界电荷对电流及近场分布的影响胡梦中;尹成友;宋铮【摘要】详细推导了考虑边界电荷时RWG-MoM分析问题中涉及的阻抗矩阵计算公式,解决了阻抗矩阵计算中遇到的面积分奇异及线积分奇异问题,尤其是线积分奇异的处理,给出了巧妙的推导.通过仿真试验研究了边界电荷对电流分布及近场的影响,发现随着物体尺寸的减小边界电荷对电流分布及近场的影响逐渐明显.【期刊名称】《系统工程与电子技术》【年(卷),期】2010(032)005【总页数】4页(P912-915)【关键词】矩量法;RWG;边界电荷【作者】胡梦中;尹成友;宋铮【作者单位】脉冲功率激光技术国家重点实验室,安徽,合肥,230037;解放军电子工程学院,安徽,合肥,230037;脉冲功率激光技术国家重点实验室,安徽,合肥,230037;解放军电子工程学院,安徽,合肥,230037;脉冲功率激光技术国家重点实验室,安徽,合肥,230037【正文语种】中文【中图分类】TN8210 引言研究发现,很多文献在利用矩量法结合 RWG(Rao-Wilton-G lisson)或共形RWG基函数分析电磁问题时,由于关心的常常是远处辐射或散射问题,常常未考虑边界处线电荷对电流分布的影响,认为边界电流为零[1-5]。

这种处理虽然在计算远处散射场及辐射场时是可取的(因为边界电荷对远处场影响很小),但理论上,这是与实际不相符的,不考虑边界处电流由于突变而产生边界电荷的影响可能使计算出的电流系数精度降低,而电流分布的计算精度对近场计算影响很大,如探测地下目标时,近场计算精度是很重要的,若能将边界电荷影响考虑到数值计算中,可能有利于提高计算小目标近场问题的精度,所以研究边界电荷对表面电流分布的影响是必要的。

相关研究比较少,仅文献[6]对该问题有一定的涉及,但该文献尚未对其进行深入的研究,那么如何才能将边界处线电荷的影响在计算阻抗矩阵时加以考虑,本文将对该问题进行详细的研究,最终得出一些具有参考价值的结论。

写出一篇高水平论文的学术工具箱!一线大佬的观点实录!

写出一篇高水平论文的学术工具箱!一线大佬的观点实录!

写出一篇高水平论文的学术工具箱!一线大佬的观点实录!2017年夏天,首届经管之家学术交流年会在北京举行,来自全国各地的18家核心期刊主编、40所大学经管类院校院长、高校及相关机构的科研工作者等500余位嘉宾齐聚北京,共同探讨了从学术前沿观点、论文写作技巧及工具使用到高效科学的投稿方式等话题。

这些干货满满的主题分享引起了听众热烈的提问和讨论(想获取海量学术科研工具资源,请在微信平台输入“经管之家论坛”或“bbspingguorg-weixin”关注微信号后留言即可获取),据统计,现场听众全天仅在正式提问环节就提出了多达30个问题,甚至包括午饭和晚饭时间也一直围绕着各位编辑老师不断请教交流。

经管之家(微信号:经管之家论坛 ID:bbspingguorg-weixin)学术交流年会进行了多场主题分享和多个环节的提问互动,论坛君经过整理,分享给大家。

这些内容不仅汇总演讲嘉宾在专题分享中讲述的精彩观点,也汇总了各提问环节大家的精彩问答。

如果小伙伴没有机会亲临现场,也可以继续关注我们的微信和微博,现场的干货您一定不会错过哦!【陈晓峰·专题分享】简介:陈晓峰老师是《科技进步与对策》编辑部主任。

本次演讲的主题是“写出一篇高水平论文的学术工具箱”。

话题1:学术工具集RESEARCH TOOLS马来西亚学者Nader Ale Ebrahim教授的RESEARCH TOOLS阅读原图:Nader教授个人主页:话题2:基于荷兰乌得勒支大学图书馆学术沟通工具使用情况调查总共有600多种工具。

大家可自行搜索了解。

话题3:关键词语义搜索工具工具1:Semantic Scholar工具2:Microsoft Academic【武京闵·专题分享】简介:武京闵老师是《中国人民大学学报》副主编、编审。

本次演讲的主题是“关于综合性学术期刊选稿用稿的几个问题”。

话题1:综合性期刊研究方法专业性期刊:实证研究越来越多,计量分析,数理模型的构建与推导。

Bookmetrix指标在学术图书影响力评价中的应用

Bookmetrix指标在学术图书影响力评价中的应用
理论研究
Bookmetrix 指标在学术图书影响力评价中的应用*
肖敖夏,杨思洛
摘 要 文章以 Bookmetrix 数据为基础,利用 SPSS 软件,建立基于 Bookmetrix 指标的学术图书因 子综合得分模型,对学术图书的影响力进行综合分析,并讨论利用 Bookmetrix 指标对学术图书影响 力进行评价的价值。研究发现,学术价值高、具有一定明星效应或具有学科基础性参考价值的图书 容易获得更高的综合得分。学术图书在社交媒体中的受关注程度相较于传统的引文呈现出更显著的 马太效应。总体而言,自然科学和应用科学的 Bookmetrix 指标数据表现优于人文学科和社会科学。 利用 Bookmetrix 指标评价学术图书对传统计量指标具有一定的补充价值,但仍存在较多不足。未来 学术成果评价应当采用分层分类的综合方法,纳入更多指标和数据,以得到更全面的分析结果。 关键词 图书影响力评价 指标应用 文献计量 Altmetrics 引用本文格式 肖敖夏,杨思洛 . Bookmetrix 指标在学术图书影响力评价中的应用[J]. 图书馆论坛, 2020,40 (9):79-85.
近年来,学术图书越来越多采用在线出版方 式,为图书提供了广泛的传播途径,也为图书评 价提供了新角度。基于新环境带来的新需求,在 线 评 价 指 标 Altmetrics 被 Jason Priem 等 提 出[5]。Altmetrics 是一种基于社交网络的科学评 价方法,它通过对科研成果的在线交流数据进行 实时追踪与采集来实现评价。相较于传统计量方 法,Altmetrics 更加全面、精确与多样[6],因而 被迅速应用于学术成果的评价。随着 Altmetrics 的发展,基于在线交流的非引用型度量指标被提 出并用于学术图书的评价。这一度量分为基于使 用情况的指标和基于社交媒体的指标两种,主要 包括书籍在相关平台的下载次数、读者标记数以 及从社交媒体上收集的书籍被提及的频率等[2]。 Bookmetrix 正是顺应这一趋势提出的,它是 Springer Nature 和 合作开发的图 书评价指标平台,汇集了一系列性能指标,能够 帮助人们了解相关图书在全球范围内的讨论、引
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Applied Psychological MeasurementDOI: 10.1177/01466216052885552007; 31; 158 Applied Psychological Measurement Kimberly S. Maier and Raymond Mapuranga Applications Book Review: Multilevel Modeling: Methodological Advances, Issues, and The online version of this article can be found at: Published by:can be found at:Applied Psychological Measurement Additional services and information for/cgi/alerts Email Alerts:/subscriptions Subscriptions:/journalsReprints.nav Reprints:/journalsPermissions.nav Permissions:Book ReviewMultilevel Modeling:MethodologicalAdvances,Issues,and ApplicationsEdited by Stephen Reise and Naihua DuanMahwah,NJ:Lawrence Erlbaum,2003,314pp.,$37.50(paperback)ISBN0-8058-5170-4Interest in multilevel modeling has exploded over the past two decades,and research applying these statistical models has become more common in educational measurement contexts.Several textbooks have emerged that introduce both the theory and application of these models and are quite useful for providing a broad overview of the model and estimation techniques as well as illustrating applications to educational research(Goldstein,2002;Hox,2002;Kreft&de Leeuw, 1998;Raudenbush&Bryk,2001;Snijders&Bosker,1999).Many of these introductory texts tend to focus on linear models(e.g.,Kreft&de Leeuw,1998;Raudenbush&Bryk,2001)and illustrate the concept of model building with linear models.Nonlinear models and novel applications of multilevel models are addressed in these books,but these topics are typically not explored to the extent of linear multilevel models.This book augments these introductory texts by providing a collection of works outlining the recent statistical advances,methodological issues,and applications that have been identified in multilevel modeling.The topic of multilevel modeling is considered more broadly,including topics in structural equation modeling,latent trait models,meta-analysis,and growth models.Fur-thermore,the methodological topics treated are diverse and cover such areas as missing data, Bayesian data analysis,the EM algorithm,and detection and treatment of outliers.The book is composed of13chapters that are written by internationally recognized researchers. Each chapter provides a description of the problem considered as well as helpful examples that illustrate each application.As the preface states,many of the book chapters involve discussions that would necessitate the reader to have a fairly sophisticated level of knowledge of not only mul-tilevel models but mathematical statistics as well.The authors suggest that this text could be useful as a supplemental text for an introductory multilevel models course.This might be a little optimis-tic,especially if the focus is on application in such a course;these students would likely have a dif-ficult time with the majority of the material.However,this book would be right at home in an advanced seminar on multilevel models and would provide the basis of discussion for a good many topics that would arise in such a seminar.Chapter1.Cudeck and du Toit present nonlinear multilevel models that are specifically used with repeated-measures data in describing individual change.The manner in which the parameters Applied Psychological Measurement,Vol.31No.2,March2007,158–160 158DOI:10.1177/0146621605288555Ó2007Sage PublicationsK.S.MAIER and R.MAPURANGABOOK REVIEW159 are estimated is presented both theoretically and with illustrative examples provided from a longi-tudinal study and a repeated-measure experiment.Chapter2.This chapter presents a method for the sensitivity analysis of hierarchical linear models.Seltzer and Choi discuss how to check the adequacy of hierarchical models under t distri-butional assumptions.This sensitivity analysis technique is illustrated using several examples through a fully Bayesian analysis approach.This analysis uses Markov chain Monte Carlo (MCMC)techniques such as Gibbs sampling and is implemented using the software packages WinBUGS and CODA(syntax available from the authors).Chapter3.A method for analyzing two-level mean and covariance structures using structural equation modeling is presented by Bentler and Liang.The maximum likelihood analysis of the two-level structural equation model is implemented via an EM algorithm as a missing data prob-lem.The authors derive the EM algorithm and describe the computation of asymptotic standard errors of the model parameters as well as the chi-squared test for modelfit.Empirical examples are provided,and a discussion of convergence and possible improvements of the algorithm are suggested.Chapter4.In this chapter,the use of growth mixture modeling for studying achievement and learning progress is presented.Muthe´n,Khoo,Francis,and Boscardin discuss the random coeffi-cient growth model and the statistical software that can be used in its analysis(e.g.,SAS PROC MIXED,MLn,HLM).In addition,a latent variable framework for modeling growth processes and multiple trajectory classes in growth mixture modeling is described.Chapter5.Multilevel models for meta-analysis are described by Hox and de Leeuw.The ran-dom effects model is presented as a general model for meta-analysis.An example and comparison with classical meta-analysis is provided.A detailed explanation of how to correct for artifacts is also given.In addition,this chapter explains how to conduct meta-analyses using the multilevel software HLM and MLwiN.Chapter6.In what may be considered an extension of Chapter4,Jo and Muthe´n explain how causal effects are estimated in growth mixture modeling of longitudinal studies that include an intervention and noncompliance using the compiler average causal effect(CACE)approach.Spe-cifically,this estimation method uses latent growth trajectories over time and covariates,which often improves precision in determining the compliance type of individuals.The assumptions of the CACE model and its modeling are presented using a maximum likelihood EM algorithm approach.In addition,empirical and simulated data illustrate the CACE estimation procedure.Chapter7.An analysis of repeated-measures data with the multilevel repeated-measures model is presented by Baumler,Harist,and Carvajal.Unlike ANOVA,which uses least squares estima-tion,the multilevel model uses maximum likelihood estimation and can be used for analyzing unbalanced designs or irregularly spaced observations.An illustrative example is included.Chapter8.A multilevel analysis of the development of social resources in a university setting is described by Bachmann and Hornung.In contrast to the other chapters,this one takes on an entirely applied statistical analysis approach.A two-level hierarchical linear model was used to analyze a longitudinal study on the use of social resources by college students.The study suggests several interestingfindings on the relationship between student resources and student characteristics.Chapter9.The use of multilevel modeling for analyzing data that is composed of ordered cate-gories and random effects is described by Fielding.The author discusses methodological develop-ments and gives related applications of these methods.In addition,model estimation using software such as MIXOR,MlwiN,and HLM is discussed in the context of generalized linear mixed models(GLMMs).In his conclusion,the author notes the need for improved estimation procedures.Chapter10.Bootstrapping is employed as a methodology to account for the effect of measure-ment error on aggregated group-level effects.Hutchison describes various methods that are used when implementing the bootstrap on errors in multilevel models.Specifically,he discusses how to resample residuals,conducting a parametric bootstrap,methods for resampling units,and a general approach to bias correction.An applied example that uses data from a longitudinal study is also given.Chapter11.Ecob and Der present an iterative method for detecting outliers in longitudinal growth analyses that use multilevel modeling.This method uses the method of empirical Bayesian estimation.The authors describe models that are used with this method and provide an illustrative example.In the example,the method converges in a few iterations,but the authors also offer sug-gestions for convergence improvement in more complex applications,and several extensions are suggested.Chapter12.Rowe demonstrates multilevel structural equation modeling as a technique that can be used when modeling hierarchically structured data in organizational psychology research. He provides an empirical example using LISREL and PRELIS.In addition,the author explains how tofit two-level variance components,conditional multilevel regression models,and multi-level structural equation st,a discussion of the strengths and limitations of multilevel and structural equation models is given.Chapter13.Reise and Duan discuss design issues in multilevel studies,focusing on the topics of sampling,experimental design,and the estimation of power.The purpose of thisfinal chapter is to describe how to improve the planning and design of multilevel studies.Interesting issues that are raised relate to allocating samples across levels,choice of estimand,cohort design,and level of randomization.Overall,the chapter emphasizes that the quality of the analysis is dependent on the quality of data collected.This text is highly recommended for methodologists and students knowledgeable of advanced statistical topics.It provides a good survey of recent statistical advances and applied approaches in multilevel modeling.One of the strengths of the book is the empirical examples given in each chapter.Kimberly S.MaierRaymond MapurangaMichigan State UniversityReferencesGoldstein,H.(2002).Multilevel statistical models (3rd ed.).London:Arnold.Hox,J.(2002).Multilevel analysis:Techniques and applications.Mahwah,NJ:Lawrence Erlbaum. Kreft,I.,&de Leeuw,J.(1998).Introducing multi-level modeling.Thousand Oaks,CA:Sage. Raudenbush,S.W.,&Bryk,A.S.(2001).Hierarchi-cal linear models:Applications and data analysis methods(2nd ed.).Thousand Oaks,CA:Sage.Snijders,T.,&Bosker,R.(1999).Multilevel analy-sis:An introduction to basic and advanced multi-level modeling.Thousand Oaks,CA:Sage.Author’s AddressAddress reprint requests to Kimberly S.Maier,451 Erickson Hall,Michigan State University,East Lan-sing,MI48824;e-mail:kmaier@.160Volume31Number2March2007APPLIED PSYCHOLOGICAL MEASUREMENT。

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