Search results for "Variable"
showing 10 items of 1674 documents
Cognition and affect: A factors combination in clients dissatisfied with restaurants
2010
On the basis of an extensive literature review of the principal theories that explain consumer dissatisfaction, we try to analyse the effect of a set of cognitive and affective variables on dissatisfaction. Cognitive variables examined were performance, expectations, disconfirmation, causal attributions and inequity. Negative affects were considered as emotional variables. We developed an empirical research to examine customer dissatisfaction with restaurants. The results indicate that the best combination of variables to estimate dissatisfaction judgements is ‘performance–inequity–norms disconfirmation–attributions’. Therefore, dissatisfaction has a greater cognitive content because negati…
Estimation de la relation de salaires de Mincer : choix de specification et enjeux économétriques
2012
In the present doctoral thesis, we estimated Mincer’s (1974) semi logarithmic wage function for the French and Pakistani labour force data. This model is considered as a standard tool in order to estimate the relationship between earnings/wages and different contributory factors. Despite of its vide and extensive use, simple estimation of the Mincerian model is biased because of different econometric problems. The main sources of bias noted in the literature are endogeneity of schooling, measurement error, and sample selectivity. We have tackled the endogeneity and measurement error biases via instrumental variables two stage least squares approach for which we have proposed two new instrum…
Scad-elastic net and the estimation of individual tourism expenditure determinants
2014
This paper introduces the use of scad-elastic net in the assessment of the determinants of individual tourist spending. This technique approaches two main estimation-related issues of primary importance. So far studies of tourism literature have made a wide use of classic regressions, whose results might be affected by multicollinearity. In addition, because of the absence of robust economic theory on tourism behavior, regressor selection is often left to researcher's choice when not driven by non-optimal automatic criteria. Scad-elastic net is an OLS model that accounts for both these problems by including two types of parameters constraints, namely the smoothly clipped absolute deviation …
Promoting mathematical skills using the instructive program Kriging
2011
Geostatistics was developed in mining for the grade estimation problems of ore deposits, nowadays; it is the most popular method for the interpolation and estimation problems. Methodological consideration about its interpolator, the Kriging, is presented in this paper. For geosciences engineering and other students in general is important to take in advance interpolation methods. This methodology is coming from natural phenomenon, where it is very difficult or even impossible to build deterministic models, only it is possible to describing the behavior from fragmented information of the problem studied. The characterization of the spatial variables using geostatistics has, in general, two m…
Parameter estimation: an advanced simulation tool in biomedicine
1990
Parameter estimation as an advanced tool in biomedicine have become extremely important in the study of biological systems. With increasing physiological knowledge and more efficient computers, modelling, simulation, and estimation have grown during the past 20 years to one of the most powerful tools of biomedical system analysis. Moreover modelling, simulation and estimation is of growing importance for determination of non-measurable parameters and state variables of biomedical systems as well as for case studies research of biomedical processes, which have been developed by physicians and system engineers and have also been widely accepted by biomedical scientists. These models already d…
Estrategias para la elaboración de modelos estadísticos de regresión
2011
Multivariable regression models are widely used in health science research, mainly for two purposes: prediction and effect estimation. Various strategies have been recommended when building a regression model: a) use the right statistical method that matches the structure of the data; b) ensure an appropriate sample size by limiting the number of variables according to the number of events; c) prevent or correct for model overfitting; d) be aware of the problems associated with automatic variable selection procedures (such as stepwise), and e) always assess the performance of the final model in regard to calibration and discrimination measures. If resources allow, validate the prediction mo…
Early prediction of reading trajectories of children with and without reading instruction in kindergarten : a comparison study of Estonia and Finland
2019
Background: The present study examined differences in the prediction of reading development and reading difficulties in Estonia (n = 348) and Finland (n = 344). These neighbouring countries share many similarities in terms of their language, orthography and educational system; however, they differ in the timing of the onset of reading instruction, which is kindergarten in Estonia and Grade 1 in Finland. Methods: Children's skills were assessed three times – fall and spring in Grade 1 and spring in Grade 2. Results: The results showed that school‐entry rapid automatised naming and reading fluency predicted the development of fluency in Grade 2, but reading fluency was a stronger predictor in…
Dynamic QoS management for multimedia real-time transmission in industrial environments
2007
The use of multimedia within industrial applications has become commonplace, targetting improved process monitoring and machine vision. In both cases, the multimedia information is commonly distributed and subject to time constraints that must be met across networks while avoiding untolerable interference over typical control flows. This can be achieved with Constant Bit-Rate (CBR) channels, typically supported by real-time protocols. However, the compressors used to reduce the amount of information to transfer generate Variable Bit-Rate (VBR) patterns. Adapting a VBR source to a CBR channel requires specific care in order to avoid wasting channel bandwidth or dropping video frames. This pa…
Getting insights into the behavior of variable speed direct expansion air conditioning systems under faulty operating conditions
2019
Direct expansion air conditioning systems, such as rooftop units, are widely adopted in small and medium scale commercial buildings. In order to increase the energy performance of these systems during part-load operation, variable-speed compressors and fans have been adopted in the last two decades. However, profitable energy saving could be achieved not only by optimizing the design and the control of these systems, but also by scheduling a proper maintenance strategy. In fact, if not properly maintained, no benefits would be achieved even when more sophisticated systems are adopted. In order to support plant owners in scheduling cost-effective maintenance program, Fault Detection and Diag…
Towards Evidence-Based Academic Advising Using Learning Analytics
2018
Academic advising is a process between the advisee, adviser and the academic institution which provides the degree requirements and courses contained in it. Content-wise planning and management of the student’ study path, guidance on studies and academic career support is the main joint activity of advising. The purpose of this article is to propose the use of learning analytics methods, more precisely robust clustering, for creation of groups of actual study profiles of students. This allows academic advisers to provide evidence-based information on the study paths that have actually happened similarly to individual students. Moreover, academic institutions can focus on management and upda…