Alexandre Abreu de Freitas

Alexandre Abreu de Freitas


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2019
Verified
Conference Paper
Closed access
ICIuri Victor Costa
Iuri Victor Costa
VQVinicius Favacho Queiroz
Vinicius Favacho Queiroz
BMBrunelli Pinto Miranda
Brunelli Pinto Miranda
AFAlexandre Abreu de Freitas
Alexandre Abreu de Freitas
CSCarlos Gustavo Resque dos Santos
Carlos Gustavo Resque dos Santos
BMBianchi Meiguins
Bianchi Meiguins
The use of objects for generating virtual content is increasingly present in the daily life of computer user. This form of interaction, called tangible interfaces, generates ways of visualizing data in different ways, such as Augmented Reality, which with the help of a given marker can present the user with a specific content. Thus, this work aims to demonstrate a prototype, which through cards as tangible objects, create, manipulate and interact with visualization techniques. Presenting the architecture developed for the development of the prototype, as well as the interaction approach according to the tasks of InfoVis. The prototype also seeks to offer collaboration among users, diversifying and facilitating learning about concepts and InfoVis.

13 February 2023 in Sensors
Verified
Journal Article
Open access
PDF file
AFAlexandre Abreu de Freitas
Alexandre Abreu de Freitas
DSDiego Hortêncio dos Santos
Diego Hortêncio dos Santos
RLRodrigo Santos do Amor Divino Lima
Rodrigo Santos do Amor Divino Lima
CSCarlos Gustavo Resque dos Santos
Carlos Gustavo Resque dos Santos
BMBianchi Meiguins
Bianchi Meiguins
New ways of interacting with computers is driving research, which is motivated mainly by the different types of user profiles. Referred to as non-conventional interactions, these are found with the use of hands, voice, head, mouth, and feet, etc. and these interactions occur in scenarios where the use of mouse and keyboard would be difficult. A constant challenge in the adoption of new forms of interaction, based on the movement of pointers and the selection of interface components, is the Midas Touch (MT) problem, defined as the involuntary action of selection by the user when interacting with the computer system, causing unwanted actions and harming the user experience during the usage process. Thus, this article aims to mitigate the TM problem in interaction with web pages using a solution centered on the Head Tracking (HT) technique. For this purpose, a component in the form of a Bar was developed and inserted on the left side of the web page, called the Pactolo Bar (PB), in order to enable or disable the clicking event during the interaction process. As a way of analyzing the effectiveness of PB in relation to TM, two stages of tests were carried out based on the collaboration of voluntary participants. The first step aims to find the data that would lead to the best configuration of the BP, while the second step aims to carry out a comparative analysis between the PB solution and the eViacam software, whose use is also focused on the HT technique. The results obtained from the use of PB were considered promising, since the analysis of quantitative data points to a significant prevention of involuntary clicks in the iteration interface and the analysis of qualitative data showed the development of a better user experience due to the ease of use, which can be noticed in elements such as the PB size, the triggering mechanism, and its positioning in the graphical interface. This study benefits in the context of the user experience, because, when using non-conventional interactions, basic items such as aspects of the graphic elements, and interaction events raise new studies that seek to mitigate the problem of the Midas Touch.

15 August 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
DSDiego Hortêncio dos Santos
Diego Hortêncio dos Santos
AFAlexandre Abreu de Freitas
Alexandre Abreu de Freitas
RLRodrigo Santos do Amor Divino Lima
Rodrigo Santos do Amor Divino Lima
CSCarlos Gustavo Resque dos Santos
Carlos Gustavo Resque dos Santos
BMBianchi Meiguins
Bianchi Meiguins
The overlap of visual items in data visualization techniques is a known problem aggravated by data volume and available visual space issues. Several methods have been applied to mitigate occlusion in data visualizations, such as random jitter, transparency, layout reconfiguration, focus+context techniques, etc. This paper aims to present a comparative study of the reading of visual variables values with partial overlap. The study focuses on categorical data representations varying the percentage limits of partial overlap and the number of distinct values for each visual variable: hue, lightness, saturation, shape, text, orientation, and texture. A computational application generated random scenarios for a unique visual pattern target to perform location tasks. Each scenario involved presentation of the visual items in a grid layout with 160 elements (10 × 16), each visual variable had from three to five distinct values encoded, and the partial overlap percentages applied, represented by a gray square in the center of each grid element, were 0% (control), 50%, 60%, and 70%. Similar to the preliminary tests, the tests conducted in this study involved 48 participants organized into four groups, with 126 tasks per participant, and the application captured the response and time for each task performed. The results analysis indicated that the hue, lightness, and shape visual variables were robust to high percentages of occlusion and gradual increase in encoded visual values. The text visual variable showed promising results for accuracy, and the resolution time was a little higher than for the last visual variables mentioned. In contrast, the texture visual variable presented lower accuracy to high levels of occlusion and more different visual encoding values. Finally, the orientation and saturation visual variables exhibited the highest error and worst perfomance rates during the tests.

21 June 2023 in Preprints.org
Verified
Preprint
Open access
PDF file
DSDiego Hortêncio dos Santos
Diego Hortêncio dos Santos
AFAlexandre Abreu de Freitas
Alexandre Abreu de Freitas
RLRodrigo Santos do Amor Divino Lima
Rodrigo Santos do Amor Divino Lima
CSCarlos Gustavo Resque dos Santos
Carlos Gustavo Resque dos Santos
BMBianchi Meiguins
Bianchi Meiguins
The overlap of visual items in data visualization techniques is a known problem aggravated by data volume and available visual space issues. Several methods have been applied to mitigate occlusion in data visualizations, such as Random Jitter, Transparency, Layout Reconfiguration, Focus+Context Techniques, etc. This paper aims to present a comparative study to read visual variables values with partial overlap. The study focuses on categorical data representations varying the percentage limits of partial overlap and the number of distinct values for each visual variable: Hue, Lightness, Saturation, Shape, Text, Orientation, and Texture. A computational application generates random scenarios for a unique visual pattern target to perform location tasks. Each scenario presented the visual items in a grid layout with 160 elements (10 x16), each visual variable had from 3 to 5 distinct values encoded, and the partial overlap percentage applied, represented by a gray square in the center o each grid element, were 0% (control), 50%, 60%, and 70%. Similar to the preliminary tests, the tests conducted in this study involved 48 participants organized into four groups, with 126 tasks per participant, and the application captured the response and time for each task performed. The result analysis indicates that the Hue, Lightness, and Shape visual variables are robust to high percentages of occlusion and gradual increase in encoded visual values. The Text visual variable show promising results for accuracy, and resolution time was a bit higher than the last visual variables mentioned. In contrast, the Texture visual variable presented lower accuracy to high levels of occlusion and more different visual encoding values. At last, the Orientation and Saturation visual variables got the highest error and worst perfomance rates during the tests.

11 November 2019
Verified
Conference Paper
Open access
PDF file
SSSalatiel D. Silva
Salatiel D. Silva
ANAdemar F. de Sousa Neto
Ademar F. de Sousa Neto
FNFrancisco M. Mendes Neto
Francisco M. Mendes Neto
AFAlexandre Abreu de Freitas
Alexandre Abreu de Freitas
ADArthur S. Domingues
Arthur S. Domingues
ISIgor Fernandes dos Santos
Igor Fernandes dos Santos
Doenças crônicas impõem diversas limitações às condições de saúde do seu portador. Estas doenças, nos últimos 10 anos, cresceram mais de 60%, tornando assim necessário um software que possa atender tanto a demanda do paciente, quanto a demanda do especialista em saúde. Dessa forma, aprender mais sobre a doença ajuda a melhorar a qualidade de vida. Web 2.0, ao longo dos anos, se tornou uma grande aliada na busca de conhecimento, possibilitando que o paciente se torne mais ativo no tratamento da sua doença. Todavia, a procura por informações que se adequem ao contexto do paciente pode ser difícil, devido ao grande volume de informações disponíveis. Este trabalho apresenta um ambiente que busca amenizar essa dificuldade, analisando o perfil do usuário, seus dados de saúde e suas relações com pessoas com o mesmo problema de saúde e assim proporcionando uma recomendação mais adequada às suas necessidades. Parte desse ambiente é constituído por um Módulo de Intermediário do Especialista que possibilita o acesso a um conjunto de informações do tratamento de pacientes, buscando tornar o tratamento dos pacientes mais adequado.