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Detalhes

Detalhes

  • Nome

    José Vasconcelos Raposo
  • Cargo

    Investigador Coordenador
  • Desde

    01 abril 2015
002
Publicações

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.

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).

2022

Validation of the Patient Health Questionnaire (PHQ-8) in a Sample of Military br

Autores
Vasconcelos Raposo, J; Sousa, DM; Teixeira, CM;

Publicação
REVISTA IBEROAMERICANA DE DIAGNOSTICO Y EVALUACION-E AVALIACAO PSICOLOGICA

Abstract
This study aimed to validate the Patient Health Questionnaire (PHQ-8) in a sample of military personnel, through the analysis of psychometric properties, reliability, and confirmatory factorial analysis. The questionnaire consists of 8 items that allow the assessment of depressive symptoms. The sample included 127 Portuguese military personnel aged between 21 and 78 years old. The results revealed a good internal consistency (alpha=.90) and good adjustment indices (chi 2/df=1.332, GFI=.956, CFI=.988, RMSEA=.051, SRMR=.30). In addition, convergent validity also showed to be good and composite reliability was .873. Thus, the PHQ-8 reveals good psychometric properties, being recommended for use in clinical practice and research with Portuguese military.

2019

Adaptation and Validation of the Temple Presence Inventory in a Portuguese Population

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

Publicação
INTERNATIONAL JOURNAL OF HUMAN-COMPUTER INTERACTION

Abstract
The present study aims to translate and validate the Temple Presence Inventory (TPI) for the Portuguese context, respecting the maintenance of an equivalent semantics as well as the validity of its contents and concepts. This study also aims to verify the psychometric properties of the instrument (factor validity and internal consistency). The sample consisted of 455 individuals (male = 271, female = 184). The fidelity of the factors varied between 0.5 and 0.84. The confirmatory factor analysis produced a theoretical model with 38 items distributed among eight factors. The covariance between some residual errors of instrument items was considered, and the following fit indices were observed: chi 2/df = 2.073; GFI = 0.858; CFI = 0.887; RSMEA = 0.049; AIC = 1527. The results confirm the appropriateness of the version adapted to the Portuguese language of the TPI and that it can be used in research projects aiming to evaluate Presence in the Portuguese-speaking population (Europe).