Estimation of nonlinear mixed-effects continuous-time models using the continuous-discrete extended Kalman filter

Many intensive longitudinal measurements are collected at irregularly spaced time intervals, and involve complex, possibly nonlinear and heterogeneous patterns of change. Effective modelling of such change processes requires continuous-time differential equation models that may be nonlinear and include mixed effects in the parameters. One approach of fitting such models is to define random effect variables as additional latent variables in a stochastic differential equation (SDE) model of choice, and use estimation algorithms designed for fitting SDE models, such as the continuous-discrete extended Kalman filter (CDEKF) approach implemented in the dynr R package, to estimate the random effect variables as latent variables. However, this approach's efficacy and identification constraints in handling mixed-effects SDE models have not been investigated. In the current study, we analytically inspect the identification constraints of using the CDEKF approach to fit nonlinear mixed-effects SDE models; extend a published model of emotions to a nonlinear mixed-effects SDE model as an example, and fit it to a set of irregularly spaced ecological momentary assessment data; and evaluate the feasibility of the proposed approach to fit the model through a Monte Carlo simulation study. Results show that the proposed approach produces reasonable parameter and standard error estimates when some identification constraint is met. We address the effects of sample size, process noise variance, and data spacing conditions on estimation results.     

Technology,gender, and history: Toward a nonlinear model of social evolution

This paper presents a new nonlinear cognitive map of social evolution— sharply departing from the conventional 19th century‐based theories of linear stages from barbarism to civilization. It draws from a data base that includes the whole of humanity (both its female and male halves). And it takes into account new data from archaeology indicating that civilization is not only thousands of years older than previously thought, but originally oriented more closely to what the author calls a Partnership rather than a Dominator model of social organization. Covering over 25,000 years of social history, this article charts major technological phase changes—from the agricultural revolution circa 10,000 years ago to the industrial and more recently electronic revolutions or modern times—from the perspective of the tension between the Dominator and Partnership models. Most critically, it shows how the present period of social disequilibrium leads us to either an evolutionary breakdown or breakthrough, with the determining factor not technology per se, but rather how effectively and quickly we shift to a social organization orienting primarily to partnership rather than domination.     

Global problems,globalization, and predictability

The term globalization is questioned in its validity and applicability to structures other than verbal. Globalization is a historical term which changes its meaning with time and culture. It is not only that its content changes but the validity of a globalization concept changes with the historical perspective. Morever, solution of global problems depends heavily on the correct analysis of the problem. Without such an analysis there is no possibility to find even an approximate solution. Hence, predictability is impossible. There is no trend which is sufficiently long to make any reliable prediction for global problems other than the most simple ones.     

Structural Equation Modeling of Social Networks: Specification,Estimation, and Application

Psychologists are interested in whether friends and couples share similar personalities or not. However, no statistical models are readily available to test the association between personalities and social relations in the literature. In this study, we develop a statistical model for analyzing social network data with the latent personality traits as covariates. Because the model contains a measurement model for the latent traits and a structural model for the relationship between the network and latent traits, we discuss it under the general framework of structural equation modeling (SEM). In our model, the structural relation between the latent variable(s) and the outcome variable is no longer linear or generalized linear. To obtain model parameter estimates, we propose to use a two-stage maximum likelihood (ML) procedure. This modeling framework is evaluated through a simulation study under representative conditions that would be found in social network data. Its usefulness is then demonstrated through an empirical application to a college friendship network.     

Reexamining Nonlinear Structural Equation Modeling Procedures: The Effect of Parallel and Congeneric Measures

The current study examines the performance of the extended unconstrained approach (EXUC) and the latent moderated structural equation modeling procedure (LMS) in situations where quadratic and interaction terms are tested simultaneously and investigates their limitations with regard to the employment of parallel and congeneric measures, relatively low indicator reliabilities, and relatively large numbers of indicators. By means of a Monte Carlo study, we found LMS to be the best option for testing multiple nonlinear effects given sufficient sample size (n ≥ 500) and normally distributed exogenous variables. Its advantages became more prominent when indicator reliabilities were heterogeneous and small. The EXUC was a viable option for estimating the model when indicators were parallel and exhibited large indicator reliabilities. An empirical example of the results is provided, and the relevance of measurement model characteristics to assess nonlinear relationships is discussed.     

颜色恒常知觉的影响因素探索及其非线性建模

采用计算机仿真技术,研究了照明、表面和背景对颜色恒常的影响,结果表明：照明性质、表面属性以及背景属性均对颜色恒常程度产生显著影响,三者的影响是相互独立的;不同照明性质对颜色恒常程度具有不同影响,中性色照明光下颜色恒常程度较高;人的颜色恒常也依赖于物体的表面属性,对不同的表面进行匹配时,表现出了颜色恒常程度的较大波动;相同背景属性较不同背景属性具有较高的颜色恒常程度。在实验研究基础上建立了非线性颜色恒常模型,该模型对实验数据进行了很好拟合,具有了一定的符合人认知特点的颜色恒常能力。     

The effects of feature type in operant serial feature-positive discriminations

In two experiments, rats were trained on two operant serial feature positive discriminations in which one feature was a flavored solution and the second feature was a visual or auditory cue. As in a previous study ([Goddard and Holland, 1996]), transfer of a feature’s control to the target of the other discrimination was not observed when the flavor feature and the reinforcer were flavored sucrose solutions (Experiment 1). The performance of comparison groups showed that this lack of transfer was not due to confounded differences in the event contingencies resulting from having similar stimuli serve as feature and reinforcer. By contrast, in Experiment 2, transfer was observed between visual and flavor features when the flavor feature was unsweetened and the reinforcer was plain sucrose. These results suggest that the lack of transfer in Experiment 1 and in [Goddard and Holland, 1996] study were related to the biological significance or hedonic properties of the sucrose feature.     

Transfert de la conscience morphologique de l’arabe langue première au français langue seconde au cours des trois premières années d’apprentissage

There is a great deal of evidence to support the role of morphological awareness in reading development. However, towards second language acquisition, transfer of morphological awareness from first to second language (L1 to L2) is still discussed. The underlying question concerns the extent to which morphological awareness is a specific or universal process, and its dependence of linguistic features. The aim of this study is to examine cross-linguistic transfer of morphological awareness from Arabic L1 to French L2 (morphological awareness and word reading) at different level of learning French L2 (F_L2). 106 Tunisian children, whose first language is Arabic, in 1st (n = 29; mean age; 8; 10 years), 2nd (n = 33; mean age; 9; 9 years) or 3rd year (n = 44; mean age; 10; 10 years) of learning F_L2 participated to this study. Their morphological awareness (inflectional or derivational oddity detection tasks) and their performance in word reading (one minute test) were assessed in standard Arabic and French, as well as their vocabulary knowledge in French. A series of fixed-order hierarchical regression analysis was performed on derivational awareness performances, inflectional awareness performances and word reading performances in F_L2, controlling for effects of other important variables (e.g. French vocabulary, French morphological awareness with word reading scores as outcome variable and French inflectional or derivational awareness with French inflectional or derivational awareness scores as outcome variable respectively, Arabic word reading, etc.). Results show significant contributions of L1 morpho-derivational awareness on F_L2 morpho-derivational awareness in 2nd year (12%), and of L1 morphological awareness on reading words F_L2 in 3^rd year (5%). These results confirm the cross-linguistic transfer of morphological awareness, particularly derivational, from L1 to L2 among alphabetic — but orthographically and morphologically distances — languages. They also suggest that such a transfer could be relatively limited. It could appear during learning process after achieving a threshold in F_L2 and before specific L2 skills take place. Thus, beyond the morphological opacity of Arabic (nonlinear morphology) and linguistic distance between Arabic and French, the morphological transfer could appear on rich and important morphological dimension in L1 and suggest dealing with the nature of cross-linguistic abilities in depth.