Search results for " Modeling"
showing 10 items of 2411 documents
UNIVERSITY STUDENTS’ GROWTH GOALS, OPPORTUNITIES FOR GOAL FULFILLMENT, AND PERCEIVED UNIVERSITY AND MESOSYSTEM SUPPORT
2021
This study assessed the relationship between students’ growth goals and perceived opportunities to achieve these goals in Latvia and the perceived support from the university and the mesosystem. Socialization models emphasize that the setting of personal goals occurs in continuous interaction with the sociocultural context, which includes perceived opportunities to achieve these goals and the interpersonal environment. Both – perceived support from close people (mesosystems) and perceived support from the university – are significant for students. The study involved 432 university students between 18 and 49. We have assessed the extent to which students’ goals regarding education, work, and…
Experimental System Identification and Black Box Modeling of Hydraulic Directional Control Valve
2015
Directional control valves play a large role in most hydraulic systems. When modeling the hydraulic systems, it is important that both the steady state and dynamic characteristics of the valves are modeled correctly to reproduce the dynamic characteristics of the entire system. In this paper, a proportional valve (Brevini HPV 41) is investigated to identify its dynamic and steady state characteristics. The steady state characteristics are identified by experimental flow curves. The dynamics are determined through frequency response analysis and identified using several transfer functions. The paper also presents a simulation model of the valve describing both steady state and dynamic charac…
Stabilization and lx -gain analysis of switched positive systems with actuator saturation
2014
This paper is concerned with the problems of stability and l 1 -gain analysis for a class of switched positive systems with time-varying delays and actuator saturation. Firstly, a convex hull representation is used to describe the saturation behavior. By constructing a multiple co-positive Lyapunov functional, sufficient conditions are provided for the closed-loop system to be locally asymptotically stable at the origin of the state space under arbitrary switching. Then, the l 1 -gain performance analysis in the presence of actuator saturation is developed. Finally, two numerical examples are provided to demonstrate the effectiveness of the proposed method.
Enhancement of the Lifetime of Metastable States in Er-Doped Si Nanocrystals by External Colored Noise
2015
The changes in the lifetime of a metastable energy level in Er-doped Si nanocrystals in the presence of an external source of colored noise are analyzed for different values of noise intensity and correlation time. Exciton dynamics is simulated by a set of phenomenological rate equations which take into account all the possible phenomena inherent in the energy states of Si nanocrystals and Er^{3+} ions in the host material of Si oxide. Electronic deexcitation is studied by examining the decay of the initial population of the Er atoms in the first excitation level 4I_{13/2} through fluorescence and cooperative energy transfer upconversion. Our results show that the deexcitation process of th…
Innovation in services through learning in a joint venture
2011
Innovation determines a firm's competitiveness and survival and a joint venture is a fast and effective way to acquire the missing knowledge that partners require to innovate, but ‘knowing how to cooperate’ can be a determining factor in achieving the successful transfer of knowledge. Employing a sample of 81 service-sector firms and using a structural equation modeling methodology, we found a positive and direct impact between the cooperative learning process and partners' commitment to innovation.
Coping and Life Satisfaction in Colombian Older Adults
2021
Background. Effective coping strategies facilitate older adults’ optimal adaptation and contribute to their well-being. Problem-focused strategies are associated with active styles and enhance well-being. This study analyzes the role of coping strategies in Colombian older adults’ subjective well-being (SWB) using structural equation modelling. Additionally, Confirmatory Factor Analyses of the Life Satisfaction Scale and Coping Strategies Questionnaires are performed. Method. A cross-sectional study is conducted with 455 Colombian older adults, ranging from 65 to 92 years old. Results. The results show that problem-focused coping has a positive effect on SWB, whereas emotion-focused coping …
Predicting Well-Being Among the Elderly: The Role of Coping Strategies
2020
Objectives: This study aims to give a wider view on the role of coping strategies on elderly’s well-being, by means of literature-based competitive structural equation models (SEM). Methods: 857 older adults were surveyed with Ryff’s scales of Psychological Well-being and the Coping Strategies Questionnaire. Competitive full SEMs were tested. Results: The best fitting model was the one in which the religious coping dimension was removed, leaving the remaining dimensions defined by problem- and emotion-focused coping, which explained both psychological and subjective well-being factors (χ2(46)=165.910, p<.001; CFI=.906; GFI=.957; RMSEA=.058 [.048, .067]). Discussion: Results pointed the rele…
Different drinking motives, different adverse consequences? Evidence among adolescents from 10 European countries
2017
INTRODUCTION AND AIM: This study, which builds on previous research demonstrating that drinking motives are associated with adverse consequences, investigates the associations between drinking motives and non-alcohol-attributed adverse consequences and disentangles alcohol-related and direct effects. DESIGN AND METHOD: On the basis of a sample of 22 841 alcohol-using 13- to 16-year-olds (50.6% female) from Belgium, Denmark, Estonia, Finland, Ireland, Portugal, Scotland, Slovakia, Switzerland and Wales, structural equation models were used to estimate direct and indirect effects. Additionally, differences across countries were tested in a multigroup analysis. RESULTS: The indirect effect (vi…
Individual, co-active and collective coping and organizational stress: A longitudinal study
2019
This study aims to identify the association between changes in three types of problem-focused coping (individual, organizational co-active and collective) and the change in the appraisal of different facets of employees' stress and the organizational stress climate. These relationships are tested by means of Bayesian Multilevel Structural Equation Modeling and a two-wave panel design. The sample is composed of 525 teachers in 100 schools. Stress experiences and coping behaviors are assessed during the first and third terms of the academic year. The results show that an increase in the use of individual problem-focused coping has little to no effect on the decrease in individual stress appra…
Social antecedents of the role stress and career-enhancing strategies of newcomers to organizations: A longitudinal study
2003
Newcomers experience uncertainty and stress following entry into an organization. Two features of socialization are important for reducing their stress: socialization tactics and relations with superiors and co-workers. The present study tests a structural equation model, including, first, the effects over time of initial institutional socialization tactics and, second, the association between social relations at the workplace on newcomers’ role stress and career-enhancing strategies, two years later, among a large (N=661) international sample of job and organization stayers. Using LISREL 8.3 the results indicate a good fit between the model and data on several fit indices. Institutional so…