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Publicações

Publicações por José Vasconcelos Raposo

2021

Assessing presence in virtual environments: adaptation of the psychometric properties of the Presence Questionnaire to the Portuguese populations

Autores
Vasconcelos Raposo, J; Melo, M; Barbosa, L; Teixeira, C; Cabral, L; Bessa, M;

Publicação
BEHAVIOUR & INFORMATION TECHNOLOGY

Abstract
Virtual Reality applications have the goal of transporting their users to a given virtual environment (VE). Thus, Presence is a consensual metric for evaluating the VEs' effectiveness. The present study adapts the Presence Questionnaire (PQ) for the Portuguese-speaking population, maintaining the validity of the contents and concepts, to ascertain the psychometric properties of the instrument.The adaptation to Portuguese was achieved through the standard adaptation process of translation and back-translation process. The sample consisted of 451 individuals (268 males and 183 females). Factor reliability ranged from 0.63 to 0.86. Confirmatory factor analysis produced a theoretical model of 21 items distributed among seven factors, where the covariance between some residual item errors was established. The fit indices obtained were , GFI , CFI , RMSEA , P [RMSEA ], MECVI . Results obtained allowed us to consider that the adapted Portuguese version of the PQ, with 21 items, forms a robust and valid questionnaire whose use is recommended to evaluate Presence in virtual reality research programmes, provided that they use samples of the Portuguese language (Europe).

2022

Do Multisensory Stimuli Benefit the Virtual Reality Experience? A Systematic Review

Autores
Melo, M; Goncalves, G; Monteiro, P; Coelho, H; Vasconcelos Raposo, J; Bessa, M;

Publicação
IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS

Abstract
The majority of virtual reality (VR) applications rely on audiovisual stimuli and do not exploit the addition of other sensory cues that could increase the potential of VR. This systematic review surveys the existing literature on multisensory VR and the impact of haptic, olfactory, and taste cues over audiovisual VR. The goal is to identify the extent to which multisensory stimuli affect the VR experience, which stimuli are used in multisensory VR, the type of VR setups used, and the application fields covered. An analysis of the 105 studies that met the eligibility criteria revealed that 84.8 percent of the studies show a positive impact of multisensory VR experiences. Haptics is the most commonly used stimulus in multisensory VR systems (86.6 percent). Non-immersive and immersive VR setups are preferred over semi-immersive setups. Regarding the application fields, a considerable part was adopted by health professionals and science and engineering professionals. We further conclude that smell and taste are still underexplored, and they can bring significant value to VR applications. More research is recommended on how to synthesize and deliver these stimuli, which still require complex and costly apparatus be integrated into the VR experience in a controlled and straightforward manner.

2022

Evaluation of the impact of different levels of self-representation and body tracking on the sense of presence and embodiment in immersive VR

Autores
Goncalves, G; Melo, M; Barbosa, L; Vasconcelos Raposo, J; Bessa, M;

Publicação
VIRTUAL REALITY

Abstract
The main goal of this paper is to investigate the effect of different types of self-representations through floating members (hands vs. hands + feet), virtual full body (hands + feet vs. full-body avatar), walking fidelity (static feet, simulated walking, real walking), and number of tracking points used (head + hands, head + hands + feet, head + hands + feet + hip) on the sense of presence and embodiment through questionnaires. The sample consisted of 98 participants divided into a total of six conditions in a between-subjects design. The HTC Vive headset, controllers, and trackers were used to perform the experiment. Users were tasked to find a series of hidden objects in a virtual environment and place them in a travel bag. We concluded that (1) the addition of feet to floating hands can impair the experienced realism (p = 0.039), (2) both floating members and full-body avatars can be used without affecting presence and embodiment (p > 0.05) as long as there is the same level of control over the self-representation, (3) simulated walking scores of presence and embodiment were similar when compared to static feet and real walking tracking data (p > 0.05), and (4) adding hip tracking overhead, hand and feet tracking (when using a full-body avatar) allows for a more realistic response to stimuli (p = 0.002) and a higher overall feeling of embodiment (p = 0.023).

2023

How Much Presence is Enough? Qualitative Scales for Interpreting the Igroup Presence Questionnaire Score

Autores
Melo, M; Gontalves, G; Vasconcelos-Raposo, J; Bessa, M;

Publicação
IEEE ACCESS

Abstract
Presence is often used to evaluate Virtual Reality (VR) applications. However, the raw scores are hard to interpret and need to be compared to other data to be meaningful. This paper leverages a database of 1909 responses to the Igroup Presence Questionnaire (IPQ) in different contexts to put forward a scale that qualitatively interprets raw Presence scores for VR experiences. The qualitative grading encompasses the acceptability dimension and analogous academic grading scales ranging from A to F and the adjective of such scores in a scale from Excellent to Unacceptable. Furthermore, the qualitative grading system encompasses Presence and its subscales Spatial Presence, Involvement, and Experienced Realism as defined by the IPQ. Adopting this grading system, supported by a robust dataset of Presence scores, enables practitioners to evaluate and interpret individual IPQ scores, allowing them to gain insights regarding the evaluated applications' effectiveness.

2012

Uma reflexão crítica sobre a prática científica e o seu contributo para a qualidade de vida da sociedade

Autores
Vasconcelos-Raposo, J; Teixeira, CM; Fernandes, HM;

Publicação
Motricidade

Abstract

2010

Preliminary Analysis of the Psychometric Properties of Ryff's Scales of Psychological Well-Being in Portuguese Adolescents

Autores
Fernandes, HM; Vasconcelos Raposo, J; Teixeira, CM;

Publicação
SPANISH JOURNAL OF PSYCHOLOGY

Abstract
This article presents a set of research studies that aim to adapt Carol Ryff's scales of psychological wellbeing (SPWB) and to analyze its psychometric properties in adolescents. The first two studies focused on the reliability and factorial validity of different Portuguese short versions of SPWB, revealing measurement models inadequacies and low internal consistency. In the third study we developed a shortened version (30 items), taking into account the application of psychometric criteria suggested by van Dierendonck (2005). The scales of this version revealed better reliability and adequate goodness of fit indices for the six-factor model, as proposed by Carol Ryff's PWB theory. Although further research focused on the psychometrical properties reanalysis of this shortened version of SPWB is needed, this article provides a contribution to the research and intervention on positive mental health during adolescence.

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