Learning Łukasiewicz logic

The integration between connectionist learning and logic-based reasoning is a longstanding foundational question in artificial intelligence, cognitive systems, and computer science in general. Research into neural-symbolic integration aims to tackle this challenge, developing approaches bridging the gap between sub-symbolic and symbolic representation and computation. In this line of work the core method has been suggested as a way of translating logic programs into a multilayer perceptron computing least models of the programs. In particular, a variant of the core method for three valued Łukasiewicz logic has proven to be applicable to cognitive modelling among others in the context of Byrne’s suppression task. Building on the underlying formal results and the corresponding computational framework, the present article provides a modified core method suitable for the supervised learning of Łukasiewicz logic (and of a closely-related variant thereof), implements and executes the corresponding supervised learning with the backpropagation algorithm and, finally, constructs a rule extraction method in order to close the neural-symbolic cycle. The resulting system is then evaluated in several empirical test cases, and recommendations for future developments are derived.     

Constructive Communication Patterns and Associated Factors Among Male Couples

Constructive communication is an important correlate to examine for sexual health promotion and HIV prevention among male couples. However, few studies have examined the effect of different relationship dynamics on both partners' perceptions of constructive communication. Using dyadic data collected from 361 male couples, the present authors explore which relationship dynamics were associated with constructive communication patterns. The results highlight the relevance of investment in a sexual agreement and trust within the relationship in perceptions of constructive communication. These findings may be particularly useful to guide the development of future dyadic-focused sexual health and HIV preventive interventions for male couples.     

Physical activity and psychosomatic-related health problems as correlates of quality of life among university students

This study aimed to investigate the role of psychosomatic problems in the relationship between physical activity and healthrelated quality of life. Participants were a convenience sample of 703 students from a South African university (males = 38.8%, females = 61.2%, mean age = 19.6 years, SD = 1.26 years). The students completed measures of physical activity, psychosomatic-related health problems and quality of life-related. The hypothesised model was tested using structural equation modelling (SEM). The empirical findings revealed that psychosomatic problems mediated the relationship between physical activity and quality of life. In fact, the mediation analyses showed a partial effect of physical activity on quality of life in that those students with less self-reported activity experienced several psychosomatic-related health problems.     

Incorporating Mobility in Growth Modeling for Multilevel and Longitudinal Item Response Data

Multilevel data often cannot be represented by the strict form of hierarchy typically assumed in multilevel modeling. A common example is the case in which subjects change their group membership in longitudinal studies (e.g., students transfer schools; employees transition between different departments). In this study, cross-classified and multiple membership models for multilevel and longitudinal item response data (CCMM-MLIRD) are developed to incorporate such mobility, focusing on students' school change in large-scale longitudinal studies. Furthermore, we investigate the effect of incorrectly modeling school membership in the analysis of multilevel and longitudinal item response data. Two types of school mobility are described, and corresponding models are specified. Results of the simulation studies suggested that appropriate modeling of the two types of school mobility using the CCMM-MLIRD yielded good recovery of the parameters and improvement over models that did not incorporate mobility properly. In addition, the consequences of incorrectly modeling the school effects on the variance estimates of the random effects and the standard errors of the fixed effects depended upon mobility patterns and model specifications. Two sets of large-scale longitudinal data are analyzed to illustrate applications of the CCMM-MLIRD for each type of school mobility.     

Evaluating feedback time delay during perturbed and unperturbed balance in handstand

Feedback delays in balance are often assessed using muscle activity onset latencies in response to discrete perturbations. The purpose of the study was to calculate EMG latencies in perturbed handstand, and determine if delays are different to unperturbed handstand. Twelve national level gymnasts completed 12 perturbed and 10 unperturbed (five eyes open and five closed) handstands. Forearm EMG latencies during perturbed handstands were assessed against delay estimates calculated via: cross correlations of wrist torque and COM displacement, a proportional and derivative model of wrist torque and COM displacement and velocity (PD model), and a PD model incorporating a passive stiffness component (PS-PD model). Delays from the PD model (161 ± 14 ms) and PS-PD model (188 ± 14 ms) were in agreement with EMG latencies (165 ± 14 ms). Cross correlations of COM displacement and wrist torque provided unrealistically low estimates (5 ± 9 ms). Delays were significantly lower during perturbed (188 ± 14 ms) compared to unperturbed handstand (eyes open: 207 ± 12 ms; eyes closed: 220 ± 19 ms). Significant differences in delays and model parameters between perturbed and unperturbed handstand support the view that balance measures in perturbed testing should not be generalised to unperturbed balance.     

学校心理环境对小学4～6年级学生学业表现的作用及条件

本研究基于具有良好全国代表性的中国儿童青少年心理发育特征数据库,使用多水平建模,分析了来自全国100个区县421所学校的心理环境特征对10826名小学4~6年级学生学业表现的影响途径及其发挥作用的条件。研究结果表明:(1)小学4~6年级学生学习动机和态度及学业成绩中分别有10.0%和33.3%的变异来自学生个体以外的学校因素。(2)在控制学生年级、性别、家庭背景和学校所在地、师资、学校学生总体家庭社会经济地位(SES)等基本特征后,学校总体和学生个体知觉两个层次的学校心理环境对学生学习动机和态度的影响均显著大于其对学生学业成绩的影响;与个体知觉到的心理环境相比,学校总体心理环境对学生学业成绩的作用相对较强。(3)学校总体心理环境对学生学业表现的影响受到学校所在地、学校师资水平、学校学生总体社会经济地位的显著调节。学校总体心理环境对处于师资水平较低、平均家庭年收入较低学校学生的学习动机和态度具有相对更强的保护作用;对处于农村、师资水平较低、平均家长文化水平较低学校学生的学业成绩具有相对更强的保护性作用。上述结果表明,学校总体心理环境对学生学业表现具有重要影响,个体知觉到的心理环境仅部分中介其作用;且学校总体心理环境对学生学业表现的作用强度受到学校所在地、师资水平和学校学生总体社会经济地位的调节。     

Developing multiple identifications through different social interactions at work

The question of how employees’ identifications with various foci at work (e.g., team, supervisor, or profession) develop and how they can be managed actively still remains largely unanswered. This is surprising, given the previously demonstrated benefits of employees’ identifications for organizational outcomes. Building on the social validation framework, we propose that changes in different social interactions (social support and effective feedback from supervisors and co-workers) over time are apt to socially validate different provisional selves and thereby differentially foster identification with the supervisor, the team, and the profession. In a longitudinal study of 212 apprentices, who are newcomers to both the organization and the profession, we test this idea using latent change scores in a structural equation modelling approach. Supporting our hypotheses, we show that changes in social support from supervisors and co-workers are related to changes in supervisor and team identification. Increased feedback from co-workers, but not from supervisors, predicted increased professional identification.     

The explanatory role of rumours in the reciprocal relationship between organizational change communication and job insecurity: a within-person approach

The current study highlights rumours as an explanation of the reciprocal relationship between perceived organizational change communication and job insecurity. First, we predict that perceiving insufficient organizational change communication may result in rumours, which in turn may shape job insecurity perceptions. Second, we propose that rumours may also mediate the relationship between job insecurity and perceiving insufficient organizational change communication. To test the hypotheses, a multilevel approach was used, in which three measurements were nested within 1994 employees. This enabled us to probe within-person processes, while controlling for possible between-person variation. The results demonstrated a negative reciprocal relationship between perceived organizational change communication and job insecurity. Additionally, rumours mediated both the negative relationship between perceived organizational change communication and subsequent job insecurity, and the negative relationship between job insecurity and subsequent perceived organizational change communication. This study contributes to the literature on job insecurity by offering initial evidence on the relationship between job insecurity and rumours, and by highlighting rumours as a process through which perceived organizational change communication and job insecurity may mutually affect each other.     

On the Multilevel Nature of Meta-Analysis: A Tutorial,Comparison of Software Programs,and Discussion of Analytic Choices

The term “multilevel meta-analysis” is encountered not only in applied research studies, but in multilevel resources comparing traditional meta-analysis to multilevel meta-analysis. In this tutorial, we argue that the term “multilevel meta-analysis” is redundant since all meta-analysis can be formulated as a special kind of multilevel model. To clarify the multilevel nature of meta-analysis the four standard meta-analytic models are presented using multilevel equations and fit to an example data set using four software programs: two specific to meta-analysis (metafor in R and SPSS macros) and two specific to multilevel modeling (PROC MIXED in SAS and HLM). The same parameter estimates are obtained across programs underscoring that all meta-analyses are multilevel in nature. Despite the equivalent results, not all software programs are alike and differences are noted in the output provided and estimators available. This tutorial also recasts distinctions made in the literature between traditional and multilevel meta-analysis as differences between meta-analytic choices, not between meta-analytic models, and provides guidance to inform choices in estimators, significance tests, moderator analyses, and modeling sequence. The extent to which the software programs allow flexibility with respect to these decisions is noted, with metafor emerging as the most favorable program reviewed.