Anderson Maciel | Universidade Federal do Rio Grande do Sul (original) (raw)

Papers by Anderson Maciel

arXiv (Cornell University), Feb 8, 2023

2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)

2020 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)

The present work proposes the use of data visualization techniques allied to an Augmented Reality... more The present work proposes the use of data visualization techniques allied to an Augmented Reality (AR) user interface to provide information for users to define the most convenient location to sit down at an event. This accounts for different sets of arbitrary demands by projecting 3D information directly atop the seats. The users can also rearrange the data to narrow down the search and switch the attribute being displayed, e.g. temperature, stage visibility, exit access or Wi-Fi signal. The proposed approach was tested against a comparable 2D interactive visualization of the same data. Each user performed twelve location choosing tasks in an average sized classroom. Qualitative and quantitative data indicated that the augmented solution is promising in some senses, exposing that AR may help users to make better decisions.

All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.

2020 22nd Symposium on Virtual and Augmented Reality (SVR), 2020

There are many uses for virtual reality (VR) in education, and there is a consensus about its con... more There are many uses for virtual reality (VR) in education, and there is a consensus about its contribution in the teaching and learning processes. However, the majority of the studies assess the effectiveness of an individual learning in VR, and there is a need to explore more on the effects of VR using different levels of immersion and collaboration. This paper presents an experiment to investigate knowledge transfer in a group-based learning game. We introduce a VR serious game to support teaching and learning processes in neuroanatomy health education. A between-subjects experiment was conducted with 23 students to jointly assess learning, knowledge retention, and sense of presence. As a control condition, grouped students assembled a physical model of the human brain, while in the experimental condition, a virtual brain was assembled. In each group, one participant assembled the brain, while the others observed and verbally collaborated in a group-based learning strategy. Results shown high mean scores in the virtual condition. When comparing the knowledge test performance before and immediately after the experiment, we found significant difference only for the virtual condition. The same can be observed for retention. Because of the promising results achieved and motivated by the need of more engaging new tools for remote learning – fully used in quarantine conditions, such as the current one because of the Covid-19 pandemic – we conducted a pilot user study to evaluate the learning effect of a remote version of our collaborative VR game.

Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems, 2017

Since immersive VR devices have become commodities, immersive environments appear as a new tool i... more Since immersive VR devices have become commodities, immersive environments appear as a new tool in the development of high-fidelity prototypes of systems in which the user interaction relies on expensive or unusual hardware, e.g., industrial systems. However, there is not enough evidence that the interface of a complex system and its VR counterpart have equal usability and user experience qualities. Our main objective is to assess the feasibility of carrying out studies on user-based evaluation in industrial interactive systems through immersive VR simulation. To achieve this, we compared user assessment with a conventional prototype of an industrial system with its immersive VR simulation. We performed within-subjects user testing in both the physical and the VR setups, and collected (i) experimenters’ observations on usability issues and (ii) subjective and objective measures of 16 participants. Subjective measures were taken using standardized questionnaires and objective measure...

With interactive maps a person can manage to find the way from one point to another, using an all... more With interactive maps a person can manage to find the way from one point to another, using an allocentric perspective (e.g. Google Maps), but also looking at a location as from the inside of the map with an egocentric perspective (e.g. Google Street View). Such experience cannot be performed with tactile maps, mostly explored from a top-view. To solve this, we built a system with two different but complementary devices. When coupled, they can provide both allocentric and egocentric spatial information to support the exploration of interactive tactile maps. To show the potential of the system, we built a blind treasure hunt.

2018 20th Symposium on Virtual and Augmented Reality (SVR), 2018

The effectiveness of Virtual Environments (VEs) may be defined in terms of different aspects. A c... more The effectiveness of Virtual Environments (VEs) may be defined in terms of different aspects. A common one is the degree to which the VE creates in the user the subjective illusion of presence, the sense of being in the VE. Since presence is a subjective condition, it has most commonly been measured by subjective methods, especially by post-questionnaires. However, objective measures have been proposed, mainly based on Electrodermal Activity (EDA), Heart Rate (HR) and Behavior Observation (BO). In this work, it was investigated the possibility of dynamically modulating the sense of presence in a Virtual Reality (VR) experience, based on physiological measures on the fly. Although these measures have already been applied for assessment in VR, whether they can be used to dynamically modulate the presence in VR experiences remain an open question. Subjective, physiological and behavioral reactions of 27 subjects during a fully immersive experience under three different conditions (NS: None Stimulus, PS: Pre-set Time Stimulus and DS: Dynamic Stimulus) were observed, varying the stimulus based on HR and EDA variation. Although it was not found a difference for the SUS presence questionnaire, it was found a significant difference for the physiological measures between the NS and DS condition, showing that it was possible to dynamically modulate the VR experience using real-time HR and EDA to increase the effectiveness of VR experiences.

ACM Computing Surveys, 2022

The effectiveness of a virtual reality experience is strongly affected by the sense of presence o... more The effectiveness of a virtual reality experience is strongly affected by the sense of presence of the users involved. This article reviews the different definitions of presence and the main proposed methods to measure it through the analysis of 1,214 papers published in the past 30 years. From the analysis of 239 user studies, we found that 85.8% used subjective measures, 11.7% used a combination of subjective and objective measures, while 2.5% used only objective measures. We also identified, from the studies reviewed, 29 main factors to evoke presence in virtual environments, grouped into four categories: Engagement, Personal Characteristics, Interaction Fidelity, and Display Fidelity.

Human-Computer Interaction – INTERACT 2021, 2021

This paper describes a new joint model for articulated human skeletons. The model is based in hum... more This paper describes a new joint model for articulated human skeletons. The model is based in human anatomy and was conceived for use in medical applications. In this model, we try to overcome some limitations of other models used in computer graphics. To validate, we compared a knee modeled with our approach with a simulator, a plastic model of a knee, and images taken during a video-arthroscopy.

Journal on Interactive Systems, 2021

Using virtual environments (VEs) is a safer and cost-effective alternative to training people in ... more Using virtual environments (VEs) is a safer and cost-effective alternative to training people in different contexts. Immersive Virtual Reality (VR), combined with game aspects, have the potential to improve the user experience in the VE by increasing realism, engagement, and motivation. In education, there is a consensus about its contribution in the teaching and learning processes. However, in Brazil, only a few research groups have developed projects that involve the development of VR for education, due to technical difficulties and high costs. This manuscript presents the development and evaluation of an VR serious game to support the learning of neuroanatomy, an extended version of our previously published paper at the SVR 2020. In this version, we present the results of four different user studies, involving 57 participants, which suggest that the VR Neuro Game is easy to use, even by inexperienced subjects in VR, and is potentially useful for teaching and learning processes, b...

Proceedings of the 1st XR in Games Workshop (XR in Games 2021), 2021

In the context of promoting a sense of empathy for the difference in people without disabilities,... more In the context of promoting a sense of empathy for the difference in people without disabilities, we propose a gaming experience that allows users to embody having a visual impairment. By occluding the user’s vision and providing spatialized audio and passive haptic feedback, allied with a speech recognition digital assistant, our goal is to offer a multi-sensory experience to enhance the user’s sense of embodiment inside a mixed reality blindness simulation. Inside the game environment, while expecting a guest to arrive, the player is required to cook a meal completely in the dark. Being aided solely by their remaining senses and a digital assistant, players must go through several tasks as to prepare dinner in time, risking to lose a love interest.

2019 IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2019

Journal on Advances in Theoretical and Applied Informatics, 2016

Aplicações médicas como simuladores virtuais de cirurgia são importantes ferramentas de estudo e ... more Aplicações médicas como simuladores virtuais de cirurgia são importantes ferramentas de estudo e treinamento para a área médica. A qualidade visual das cenas virtuais beneficia o desenvolvimento de habilidades pertinentes, de acordo com o conceito de simulação PSVR (\textit{Patient Specific Virtual Reality}). Neste contexto, técnicas de representação gráfica de tecidos orgânicos são fundamentais para o realismo de tais simulações. A Computação Gráfica apresenta abordagens características, que podem ser classificadas de acordo com o processo de simulação da interação entre a luz e o material orgânico. O presente trabalho apresenta as principais contribuições para a simulação de tecido humano vivo, principalmente de órgãos internos, e propõe uma nova taxonomia para tais métodos.

2016 IEEE Symposium on 3D User Interfaces (3DUI), 2016

2015 28th SIBGRAPI Conference on Graphics, Patterns and Images, 2015

Agents path planning is an essential part of games and crowd simulations. In those contexts they ... more Agents path planning is an essential part of games and crowd simulations. In those contexts they are usually restricted to planar surfaces due to the huge computational cost of mapping arbitrary surfaces to a plane without distortions. Mapping is required to benefit from the lower computational cost of distance calculations on a plane (Euclidean distance) when compared to distances on arbitrary surfaces (Geodesic distance). Although solutions have been presented, none have properly handled non-planar surfaces around the agent. In this paper we present mesh parametrization techniques to unfold the region around the agent allowing to extend to arbitrary surfaces the use of existing path planning algorithms initially designed only for planar surfaces. To mitigate the high computational cost of unfolding the entire surface dynamically, we propose pre-processing stages and massive parallelization, resulting in performances similar to that of using a planar surface. We also present a GPU implementation schema that permits a solution to be computed in real-time allowing agents to navigate on deformable surfaces that require dynamic unfolding of the surface. We present results with over 100k agents to prove the approach practicality.

2014 XVI Symposium on Virtual and Augmented Reality, 2014

The occurrence of accidents in the workplace generates huge losses related to the human safety an... more The occurrence of accidents in the workplace generates huge losses related to the human safety and the financial costs involved. Thus, large companies have been investing in the development of tools that help both the risk perception and training of workers in their basic tasks. This paper presents the development of an immersive simulator and its application for risk analysis. The unique feature of our simulator is that it runs on a regular smartphone coupled to a physical plug-in designed to allow immersive stereo viewing. The system usability was tested with user experiments, being well received. This design provides low cost and excellent scalability as it is based on self owned devices and off-the-shelf add-ons.

arXiv (Cornell University), Feb 8, 2023

2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)

2020 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)

The present work proposes the use of data visualization techniques allied to an Augmented Reality... more The present work proposes the use of data visualization techniques allied to an Augmented Reality (AR) user interface to provide information for users to define the most convenient location to sit down at an event. This accounts for different sets of arbitrary demands by projecting 3D information directly atop the seats. The users can also rearrange the data to narrow down the search and switch the attribute being displayed, e.g. temperature, stage visibility, exit access or Wi-Fi signal. The proposed approach was tested against a comparable 2D interactive visualization of the same data. Each user performed twelve location choosing tasks in an average sized classroom. Qualitative and quantitative data indicated that the augmented solution is promising in some senses, exposing that AR may help users to make better decisions.

All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.

2020 22nd Symposium on Virtual and Augmented Reality (SVR), 2020

There are many uses for virtual reality (VR) in education, and there is a consensus about its con... more There are many uses for virtual reality (VR) in education, and there is a consensus about its contribution in the teaching and learning processes. However, the majority of the studies assess the effectiveness of an individual learning in VR, and there is a need to explore more on the effects of VR using different levels of immersion and collaboration. This paper presents an experiment to investigate knowledge transfer in a group-based learning game. We introduce a VR serious game to support teaching and learning processes in neuroanatomy health education. A between-subjects experiment was conducted with 23 students to jointly assess learning, knowledge retention, and sense of presence. As a control condition, grouped students assembled a physical model of the human brain, while in the experimental condition, a virtual brain was assembled. In each group, one participant assembled the brain, while the others observed and verbally collaborated in a group-based learning strategy. Results shown high mean scores in the virtual condition. When comparing the knowledge test performance before and immediately after the experiment, we found significant difference only for the virtual condition. The same can be observed for retention. Because of the promising results achieved and motivated by the need of more engaging new tools for remote learning – fully used in quarantine conditions, such as the current one because of the Covid-19 pandemic – we conducted a pilot user study to evaluate the learning effect of a remote version of our collaborative VR game.

Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems, 2017

Since immersive VR devices have become commodities, immersive environments appear as a new tool i... more Since immersive VR devices have become commodities, immersive environments appear as a new tool in the development of high-fidelity prototypes of systems in which the user interaction relies on expensive or unusual hardware, e.g., industrial systems. However, there is not enough evidence that the interface of a complex system and its VR counterpart have equal usability and user experience qualities. Our main objective is to assess the feasibility of carrying out studies on user-based evaluation in industrial interactive systems through immersive VR simulation. To achieve this, we compared user assessment with a conventional prototype of an industrial system with its immersive VR simulation. We performed within-subjects user testing in both the physical and the VR setups, and collected (i) experimenters’ observations on usability issues and (ii) subjective and objective measures of 16 participants. Subjective measures were taken using standardized questionnaires and objective measure...

With interactive maps a person can manage to find the way from one point to another, using an all... more With interactive maps a person can manage to find the way from one point to another, using an allocentric perspective (e.g. Google Maps), but also looking at a location as from the inside of the map with an egocentric perspective (e.g. Google Street View). Such experience cannot be performed with tactile maps, mostly explored from a top-view. To solve this, we built a system with two different but complementary devices. When coupled, they can provide both allocentric and egocentric spatial information to support the exploration of interactive tactile maps. To show the potential of the system, we built a blind treasure hunt.

2018 20th Symposium on Virtual and Augmented Reality (SVR), 2018

The effectiveness of Virtual Environments (VEs) may be defined in terms of different aspects. A c... more The effectiveness of Virtual Environments (VEs) may be defined in terms of different aspects. A common one is the degree to which the VE creates in the user the subjective illusion of presence, the sense of being in the VE. Since presence is a subjective condition, it has most commonly been measured by subjective methods, especially by post-questionnaires. However, objective measures have been proposed, mainly based on Electrodermal Activity (EDA), Heart Rate (HR) and Behavior Observation (BO). In this work, it was investigated the possibility of dynamically modulating the sense of presence in a Virtual Reality (VR) experience, based on physiological measures on the fly. Although these measures have already been applied for assessment in VR, whether they can be used to dynamically modulate the presence in VR experiences remain an open question. Subjective, physiological and behavioral reactions of 27 subjects during a fully immersive experience under three different conditions (NS: None Stimulus, PS: Pre-set Time Stimulus and DS: Dynamic Stimulus) were observed, varying the stimulus based on HR and EDA variation. Although it was not found a difference for the SUS presence questionnaire, it was found a significant difference for the physiological measures between the NS and DS condition, showing that it was possible to dynamically modulate the VR experience using real-time HR and EDA to increase the effectiveness of VR experiences.

ACM Computing Surveys, 2022

The effectiveness of a virtual reality experience is strongly affected by the sense of presence o... more The effectiveness of a virtual reality experience is strongly affected by the sense of presence of the users involved. This article reviews the different definitions of presence and the main proposed methods to measure it through the analysis of 1,214 papers published in the past 30 years. From the analysis of 239 user studies, we found that 85.8% used subjective measures, 11.7% used a combination of subjective and objective measures, while 2.5% used only objective measures. We also identified, from the studies reviewed, 29 main factors to evoke presence in virtual environments, grouped into four categories: Engagement, Personal Characteristics, Interaction Fidelity, and Display Fidelity.

Human-Computer Interaction – INTERACT 2021, 2021

This paper describes a new joint model for articulated human skeletons. The model is based in hum... more This paper describes a new joint model for articulated human skeletons. The model is based in human anatomy and was conceived for use in medical applications. In this model, we try to overcome some limitations of other models used in computer graphics. To validate, we compared a knee modeled with our approach with a simulator, a plastic model of a knee, and images taken during a video-arthroscopy.

Journal on Interactive Systems, 2021

Using virtual environments (VEs) is a safer and cost-effective alternative to training people in ... more Using virtual environments (VEs) is a safer and cost-effective alternative to training people in different contexts. Immersive Virtual Reality (VR), combined with game aspects, have the potential to improve the user experience in the VE by increasing realism, engagement, and motivation. In education, there is a consensus about its contribution in the teaching and learning processes. However, in Brazil, only a few research groups have developed projects that involve the development of VR for education, due to technical difficulties and high costs. This manuscript presents the development and evaluation of an VR serious game to support the learning of neuroanatomy, an extended version of our previously published paper at the SVR 2020. In this version, we present the results of four different user studies, involving 57 participants, which suggest that the VR Neuro Game is easy to use, even by inexperienced subjects in VR, and is potentially useful for teaching and learning processes, b...

Proceedings of the 1st XR in Games Workshop (XR in Games 2021), 2021

In the context of promoting a sense of empathy for the difference in people without disabilities,... more In the context of promoting a sense of empathy for the difference in people without disabilities, we propose a gaming experience that allows users to embody having a visual impairment. By occluding the user’s vision and providing spatialized audio and passive haptic feedback, allied with a speech recognition digital assistant, our goal is to offer a multi-sensory experience to enhance the user’s sense of embodiment inside a mixed reality blindness simulation. Inside the game environment, while expecting a guest to arrive, the player is required to cook a meal completely in the dark. Being aided solely by their remaining senses and a digital assistant, players must go through several tasks as to prepare dinner in time, risking to lose a love interest.

2019 IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2019

Journal on Advances in Theoretical and Applied Informatics, 2016

Aplicações médicas como simuladores virtuais de cirurgia são importantes ferramentas de estudo e ... more Aplicações médicas como simuladores virtuais de cirurgia são importantes ferramentas de estudo e treinamento para a área médica. A qualidade visual das cenas virtuais beneficia o desenvolvimento de habilidades pertinentes, de acordo com o conceito de simulação PSVR (\textit{Patient Specific Virtual Reality}). Neste contexto, técnicas de representação gráfica de tecidos orgânicos são fundamentais para o realismo de tais simulações. A Computação Gráfica apresenta abordagens características, que podem ser classificadas de acordo com o processo de simulação da interação entre a luz e o material orgânico. O presente trabalho apresenta as principais contribuições para a simulação de tecido humano vivo, principalmente de órgãos internos, e propõe uma nova taxonomia para tais métodos.

2016 IEEE Symposium on 3D User Interfaces (3DUI), 2016

2015 28th SIBGRAPI Conference on Graphics, Patterns and Images, 2015

Agents path planning is an essential part of games and crowd simulations. In those contexts they ... more Agents path planning is an essential part of games and crowd simulations. In those contexts they are usually restricted to planar surfaces due to the huge computational cost of mapping arbitrary surfaces to a plane without distortions. Mapping is required to benefit from the lower computational cost of distance calculations on a plane (Euclidean distance) when compared to distances on arbitrary surfaces (Geodesic distance). Although solutions have been presented, none have properly handled non-planar surfaces around the agent. In this paper we present mesh parametrization techniques to unfold the region around the agent allowing to extend to arbitrary surfaces the use of existing path planning algorithms initially designed only for planar surfaces. To mitigate the high computational cost of unfolding the entire surface dynamically, we propose pre-processing stages and massive parallelization, resulting in performances similar to that of using a planar surface. We also present a GPU implementation schema that permits a solution to be computed in real-time allowing agents to navigate on deformable surfaces that require dynamic unfolding of the surface. We present results with over 100k agents to prove the approach practicality.

2014 XVI Symposium on Virtual and Augmented Reality, 2014

The occurrence of accidents in the workplace generates huge losses related to the human safety an... more The occurrence of accidents in the workplace generates huge losses related to the human safety and the financial costs involved. Thus, large companies have been investing in the development of tools that help both the risk perception and training of workers in their basic tasks. This paper presents the development of an immersive simulator and its application for risk analysis. The unique feature of our simulator is that it runs on a regular smartphone coupled to a physical plug-in designed to allow immersive stereo viewing. The system usability was tested with user experiments, being well received. This design provides low cost and excellent scalability as it is based on self owned devices and off-the-shelf add-ons.

Collaboration in 3D environments has the main goal of attaining a high degree of teamwork by expo... more Collaboration in 3D environments has the main goal of attaining a high degree of teamwork by exposing the team to a suitable level of immersion. However, users within virtual environments have limitations to perceive the same stimuli of the real world. Particularly, the feeling of presence and nearness of the other is difficult to be generated in VR systems. This poster presents a work in progress that shows our current results on evaluating the impact of three different proximity cues for generating awareness of the presence of other. The design of each cue aims at independently stimulating the senses of sight, hearing and touch. The experiment design includes the comparison with a baseline condition in virtual environments where no specific stimulation is applied.