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Publications

Publications by Maximino Bessa

2016

Adaptation and Validation of the Igroup Presence Questionnaire (IPQ) in a Portuguese Sample

Authors
Vasconcelos Raposo, J; Bessa, M; Melo, M; Barbosa, L; Rodrigues, R; Teixeira, CM; Cabral, L; Sousa, AA;

Publication
PRESENCE-TELEOPERATORS AND VIRTUAL ENVIRONMENTS

Abstract
The present study aims (a) to translate and adapt the Igroup Presence Questionnaire (IPQ) to the Portuguese context (semantic equivalence/ conceptual and content validity) and (b) to examine its psychometric properties (reliability and factorial validity). The sample consisted of 478 subjects (285 males and 193 females). The fidelity of the factors varied between 0.53 and 0.83. The confirmatory factor analysis results produced a 14-item version of IPQ-PT, accepting covariance between residual errors of some items of the instrument, as the best structural representation of the data analyzed. The CFA was conducted based on a three-variable model. The fit indexes obtained were X-2/df = 2.647, GFI = .948, CFI = .941, RSMEA = .059, and AIC = 254. These values demonstrate that the proposed Portuguese translation of the IPQ maintains its original validity, demonstrating it to be a robust questionnaire to measure the sense of presence in virtual reality studies. It is therefore recommended for use in presence research when using Portuguese samples.

2016

Does 3D 360 video enhance user's VR experience?: An Evaluation Study

Authors
Bessa, Maximino; Melo, Miguel; Narciso, David; Barbosa, Luis; Raposo, JoseVasconcelos;

Publication
Proceedings of the XVII International Conference on Human Computer Interaction, Interacción 2016, Salamanca, Spain, September 13 - 16, 2016

Abstract
Technology for virtual reality has evolved at a fast pace and so is its affordability. Equipment such as head-mounted displays are now available for the average consumer at reasonable prices and this potentiates the use of contents such as video 360 in a more natural way. The purpose of this study was to measure the sense of presence and cybersickness comparing subjects by gender while experiencing a virtual reality application composed by type of VIDEO (360 video and 3D 360 video) using an head-mounted display. A Portuguese version of the Igroup Presence Questionnaire (IPQ) was used together with the Simulator Sickness Questionnaire (SSQ). The results have revealed that there are no significant differences across 2D and 3D videos in the sense of presence or cybersickness. © 2016 ACM.

2016

HDR video on mobile devices Unlocker of new opportunities for digital business

Authors
Melo, M; Barbosa, L; Meira, C; Branco, F; Bessa, M;

Publication
2016 11TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)

Abstract
Prior to having available the High Dynamic Range (HDR) techniques, certain levels of luminance could only by captured by the human eye. Currently, HDR technology overcomes the limitations of conventional imaging technology (also referred as Low Dynamic Range or LDR) and allows the capture and delivery of contents that can match the dynamic range of the real world. However, the state of the art of HDR video focus mainly on conventional sized displays typical of TVs or PCs. As the usage of mobile devices for multimedia consumption is increasing considerably, there is a need for studying the impact of the viewing of HDR video on such devices. This will allow to take full advantage of HDR technology, creating a set of opportunities for the digital business as it allows, among others, the presentation of products in a much more efficient and captivating way. On this paper it is presented a study that evaluates the impact of the HDR video delivery on mobile devices and compares it with the impact of Low Dynamic Range (LDR) content. Results show that the delivery of HDR video on mobiles is possible without requiring much more resources when comparing the delivery of LDR video.

2016

Immersive Virtual Environments of Simulation for Exposure Therapy Impact of Multi-sensory Stimulation in the Sense of Presence in an Acrophobic Context

Authors
Bessa, J; Barreira, J; Faria, N; Martins, J; Barbosa, L; Bessa, M;

Publication
2016 11TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)

Abstract
In the last three decades with the Information Technologies advent and the growth of the concept of Virtual Environments, a set of new ways to perform tasks have emerged, in the most diversified areas of society. The main focus of this work was to verify if it was possible to increase the sense of presence through multi-sensory stimulation, creating a virtual environment of simulation that causes stress in exposure therapy, in this case in people who have a fear of heights. The evaluation of the sense of presence was made using the Portuguese version of a previously validated IPQ (Igroup Presence Questionnaire) and also through direct observation of the movements caused by oculomotor reflexes. Although the achievement results that were not very significant between the two tested groups, the multisensory simulation environment obtained better results in terms of involvement in relation to space and realism, which increased concentration in the experience. The obtained results seem to indicate that the alone addition of further stimuli does not lead to an increased feeling of presence, therefore existing the need to understand which are the critical stimuli for each assessment situation.

2015

Information system for the management and visualization of multisensorial contents

Authors
Freitas, J; Meira, C; Melo, M; Barbosa, L; Bessa, M;

Publication
PROCEEDINGS OF THE 2015 10TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI 2015)

Abstract
Humans sense the surrounding environment through five senses: sight, hearing, taste, smell and touch. This is valid not only for real life but also when one is exposed to virtual environments. It already exists systems that exploit the sensorial stimulation of more than one sense, however there are no available low-cost solutions that allow creative professionals to create and visualize multisensory contents. On this paper it is presented a solution for the creation and delivery of multisensory contents that allow users to create their own multisensory experiments. An evaluation of the developed solution that shows the potential of these new contents is also described.

2015

Many-objective optimization with corner-based search

Authors
Freire, H; de Moura Oliveira, PBD; Solteiro Pires, EJS; Bessa, M;

Publication
MEMETIC COMPUTING

Abstract
The performance of multi-objective evolutionary algorithms can severely deteriorate when applied to problems with 4 or more objectives, called many-objective problems. For Pareto dominance based techniques, available information about some optimal solutions can be used to improve their performance. This is the case of corner solutions. This work considers the behaviour of three multi-objective algorithms [Non-dominated sorting genetic algorithm (NSGA-II), Speed-constrained multi-objective particle swarm optimization (SMPSO) and generalized differential evolution (GDE3)] when corner solutions are inserted into the population at different evolutionary stages. The problem of finding corner solutions is addressed by proposing a new algorithm based in multi-objective particle swarm optimization (MOPSO). Results concerning the behaviour of the aforementioned algorithms in five benchmark problems (DTLZ1-5) and respective analysis are presented.

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