Search results for " Invariance"
showing 10 items of 219 documents
Extended scale-invariant pattern recognition with white-light illumination.
2000
A previous method of obtaining scale-invariance detection with white-light illumination has been improved on. We were able to detect different scaled versions of the target up to a magnification factor equal to 2. We simultaneously detected several versions in the same scene, because each scale factor is codified in a different wavelength. Experimental results demonstrate the proposed technique and show the utility of the method.
Real filter based on Mellin radial harmonics for scale-invariant pattern recognition.
1994
Several theoretical and experimental studies are developed in order to simplify the construction of filters based on Mellin radial harmonics (MRH) for scale-invariant pattern recognition. A real filter based on MRH is designed. The impulse response of the filter is a hermitic function, obtained by a suitable modification of a MRH component. This real filter has the same scale invariance as the conventional complex MRH filters, with the main advantage of its simplicity. Both computer simulations and optical experiments are presented.
Method for determining the proper expansion center and order for Mellin radial harmonic filters
1993
Abstract A method to improve the behaviour of the Mellin radial harmonic (MRH) filters in scale invariant pattern recognition is presented. An algorithm has been introduced to obtain the proper expansion center and order of the MRH development of any object. The procedure consists of the suspression of the non-discriminant uniform background in the energy function of the target. Computer simulations are presented.
Evidence of validity and measurement invariance by gender of the Vaccination Attitudes Examination (VAX) scale in Colombian university students
2022
Background: Having a valid tool to assess attitudes toward vaccination and identify the concerns that drive vaccine refusal can facilitate population studies and help guide public health interventions. The objective of this study has been to adapt the Vaccination Attitudes Examination (VAX) scale in Colombian university students and to study its psychometric properties in a non-probabilistic sample of 1074 Colombian university students. Methods: A confirmatory factor analysis was used to study the factorial structure. A structural equation model was tested to study concurrent validity and to check whether the factors predicted having received the coronavirus vaccine. Gender-based measuremen…
Multiple solutions with sign information for semilinear Neumann problems with convection
2019
We consider a semilinear Neumann problem with convection. We assume that the drift coefficient is indefinite. Using the theory of nonlinear operators of monotone type, together with truncation and comparison techniques and flow invariance arguments, we prove a multiplicity theorem producing three nontrivial smooth solutions (positive, negative and nodal).
Psychometric properties of the stress control mindset measure in university students from Australia and the UK
2021
Abstract Introduction Beliefs about the consequences of stress, stress mindsets, are associated with health and performance outcomes under stress. This article reports the development and examination of the psychometric properties of a measure of stress mindset: The Stress Control Mindset Measure (SCMM). The measure is consistent with theory on mindsets about self‐attributes and conceptualizes stress mindset as the extent to which individuals endorse beliefs that stress can be enhancing. Methods The study adopted a correlational cross‐sectional survey design in two student samples. Undergraduate students from an Australian university (Sample 1, N = 218) and a UK university (Sample 2, N = 21…
Assessing the measurement invariance of a Latin-American Spanish translation of the Body Appreciation Scale-2 in Mexican, Argentinean, and Colombian …
2020
In order to advance in the study of positive body image among different cultures, it is important to create culturally appropriate measures. We examined the psychometric properties of a Latin-American Spanish translation of the Body Appreciation Scale-2 (BAS-2; Tylka & Wood-Barcalow, 2015a), specifically assessing measurement invariance using a large sample of 3845 male and female adolescents from Argentina, Mexico, and Colombia. Participants completed the BAS-2, Eating Disorder Inventory-2, Male Body Attitude Scale and the Sociocultural Attitudes Toward Appearance Questionnaire-3. The BAS-2 had a unidimensional factor structure in each of the three samples. We confirmed the structural, met…
Testing Measurement Invariance Across Spanish and English Versions of the Physical Self-Description Questionnaire : An Application of Exploratory Str…
2014
Test of measurement invariance across translated versions of questionnaires is a critical prerequisite to comparing scores on the different versions. In this study, we used exploratory structural equation modeling (ESEM) as an alternative approach to evaluate the measurement invariance of the Spanish version of the Physical Self-Description Questionnaire (PSDQ). The two versions were administered to large samples of Australian and Spanish adolescents. First, we compared the CFA and ESEM approaches and showed that ESEM fitted the data much better and resulted in substantially more differentiated factors. We then tested measurement invariance with a 13-model ESEM taxonomy. Results justified u…
A Confirmatory Factor Analysis of the “Autoconcepto Forma 5” Questionnaire in Young Adults from Spain and Chile
2011
The aim of this work is to examine the pentafactorial validity of the AF5 Self-Concept Questionnaire in Spanish and Chilean young adults. From the responses of a total of 4,383 young adults aged 17 to 22 years (1,918 Spanish, 44%, and 2,465 Chilean, 56%) it was analyzed the reliability of the instrument, the compared validity of the 5 oblique factor model proposed by the authors versus the unifactorial and the orthogonal alternative models, and was studied the invariance of one Chilean sample. The results of confirmatory factor analyses supported the authors' pentafactorial model. The multi-group factorial invariance showed that Chilean sample of the AF5 does not change neither the Spanish …
Does the Spanish version of the SWLS measure the same in Spain and Peru?
2019
Aim Satisfaction with life is a measure of protection in older adults. There lies the importance of providing quality instruments. The aim of the study was to evaluate the invariance of the life satisfaction scale (SWLS) in two samples of older adults in Spain and Peru. Method The participants were 857 older adults in Spain (mean age = 68.23 years, SD = 5.93) and 336 older adults in Peru (average age = 72.42, SD = 7.07). All multi-group confirmatory factor analyzes were estimated in Mplus 8.0. Results The results indicate the presence of a strict invariance of the one-dimensional structure of the SWLS in samples of older adults in Spain and Peru, which allows for meaningful comparisons of l…