2015
Autores
Matos, A; Rocha, T; Cabral, L; Bessa, M;
Publicação
PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON SOFTWARE DEVELOPMENT AND TECHNOLOGIES FOR ENHANCING ACCESSIBILITY AND FIGHTING INFO-EXCLUSION
Abstract
In this paper we present a study about multi-sensory content within the context of learning activities aimed at people with intellectual disability. A story was prepared together with traditional stimulus (audio and visual) and multisensory (audio, video, tactile and smell). Knowing that people with intellectual disability, due to their cognitive limitation, have multiple learning difficulties, namely in areas such as: communication, reading/writing and attention [1], it is really important to create innovative and pedagogically effective solutions that may motivate them and assist their learning process. Therefore, this study presents Preliminary results showing an overall improvement regarding the participant's memory when using the very multi-sensory contents. (C) 2015 The Authors. Published by Elsevier B.V.
2015
Autores
Melo, M; Bessa, M; Barbosa, L; Debattista, K; Chalmers, A;
Publicação
EURASIP JOURNAL ON IMAGE AND VIDEO PROCESSING
Abstract
This paper presents an evaluation of high-dynamic-range (HDR) video tone mapping on a small screen device (SSD) under reflections. Reflections are common on mobile devices as these devices are predominantly used on the go. With this evaluation, we study the impact of reflections on the screen and how different HDR video tone mapping operators (TMOs) perform under reflective conditions as well as understand if there is a need to develop a new or hybrid TMO that can deal with reflections better. Two well-known HDR video TMOs were evaluated in order to test their performance with and without on-screen reflections. Ninety participants were asked to rank the TMOs for a number of tone-mapped HDR video sequences on an SSD against a reference HDR display. The results show that the greater the area exposed to reflections, the larger the negative impact on a TMO's perceptual accuracy. The results also show that under observed conditions, when reflections are present, the hybrid TMOs do not perform better than the standard TMOs.
2015
Autores
Carvalho, DCM; Bessa, MEC; Magalhaes, LGM; Carrapatoso, EMEM;
Publicação
IEEE LATIN AMERICA TRANSACTIONS
Abstract
Novel input modalities such as touch, tangibles or gestures try to exploit human's innate skills rather than imposing new learning processes. However, despite the recent boom of different natural interaction paradigms, it hasn't been systematically evaluated how these interfaces influence a user's performance or whether each interface could be more or less appropriate when it comes to: 1) different age groups; and 2) different basic operations, as data selection, insertion or manipulation. This work presents the first step of an exploratory evaluation about whether or not the users' performance is indeed influenced by the different interfaces. The key point is to understand how different interaction paradigms affect specific target-audiences (children, adults and older adults) when dealing with a selection task. 60 participants took part in this study to assess how different interfaces may influence the interaction of specific groups of users with regard to their age. Four input modalities were used to perform a selection task and the methodology was based on usability testing (speed, accuracy and user preference). The study suggests a statistically significant difference between mean selection times for each group of users, and also raises new issues regarding the "old" mouse input versus the "new" input modalities.
2015
Autores
Rocha, T; Bessa, M; Magalhães, L; Cabral, L;
Publicação
ACM International Conference Proceeding Series
Abstract
With this study we intent to better understand how a group with intellectual disabilities interacts with digital content, namely web content, when performing equivalent tasks from their daily school activities, such as: painting, making puzzles, playing games. To accomplish this we observed how a group with intellectual disabilities, without experience using computers, performed universal tasks (selection, manipulation and navigation) when presented with different activities on the Web such as painting, playing games or searching. We aimed at evaluating usability and accessibility and for this we registered the following variables: successful conclusion of activities, type of difficulties found, errors, satisfaction, motivation and autonomy indicators. Participants showed motivation and learning skills when performing all the three universal tasks (selection, manipulation and navigation) which is confirmed by the number of participants that was able to conclude the activities. Concerning errors, it was observed that despite the large number of errors made by the participants, their motivation lead them to complete the tasks. When handling the input devices the participants had a good performance using the computer mouse. On the other hand, they could not use the keyboard alone because of their reading/ writing difficulties. © 2015 ACM.
2015
Autores
Carvalho, D; Magalhães, L; Bessa, M; Carrapatoso, E;
Publicação
ACM International Conference Proceeding Series
Abstract
The recent advances made in human-computer interaction have allowed us to manipulate digital contents exploiting recognitionbased technologies. However, no work has been reported that evaluates how these interfaces influence the performance of different user groups. With the appearance of multiple sensors and controllers for hand gesture recognition, it becomes important to understand if these groups have similar performance levels concerning gestural interaction, and if some sensors could induce better results than others when dealing with users of different age brackets. In this respect, it could also be important to realize if the device's sensor accuracy in terms of hand / full body recognition influences interaction performance. We compare two gesturesensing devices (Microsoft Kinect and Leap Motion) using Fitts' law to evaluate target acquisition performances, with relation to users' age differences. In this article, we present the results of an experiment implemented to compare the groups' performance using each of the devices and also realize which one could yield better results. 60 subjects took part in this study and they were asked to select 50 targets on the screen as quickly and accurately as possible using one of the devices. Overall, there was a statistically significant difference in terms of performance between the groups in the selection task. On the other hand, users' performance showed to be rather consistent when comparing both devices side by side in each group of users, which may imply that the device itself does not influence performance but actually the type of group does. © 2015 ACM.
2015
Autores
Melo, M; Bessa, M; Debattista, K; Chalmers, A;
Publicação
COMPUTER GRAPHICS FORUM
Abstract
Since high dynamic range (HDR) displays are not yet widely available, there is still a need to perform a dynamic range reduction of HDR content to reproduce it properly on standard dynamic range (SDR) displays. The most common techniques for performing this reduction are termed tone-mapping operators (TMOs). Although mobile devices are becoming widespread, methods for displaying HDR content on these SDR screens are still very much in their infancy. While several studies have been conducted to evaluate TMOs, few have been done with a goal of testing small screen displays (SSDs), common on mobile devices. This paper presents an evaluation of six state-of-the-art HDR video TMOs. The experiments considered three different levels of ambient luminance under which 180 participants were asked to rank the TMOs for seven tone-mapped HDR video sequences. A comparison was conducted between tone-mapped HDR video footage shown on an SSD and on a large screen SDR display using an HDR display as reference. The results show that there are differences between the performance of the TMOs under different ambient lighting levels and the TMOs that perform well on traditional large screen displays also perform well on SSDs at the same given luminance level.
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