Celmar Guimarães da Silva

State University of Campinas (UNICAMP) | UNICAMP · Divisão Tecnológica de Informática (DTI)

The User Interface (UI) is the first artefact that the user interacts with while developing a sense of trust that motivates him to use software applications more effectively. A badly designed UI can deceive users and bring the system into disrepute. Trustworthiness in UI is mandatory, as a poorly implemented UI can lead to the user misusing the sys...

Petroleum engineers usually create a set of hundreds of models of a given oil reservoir under analysis to represent its uncertainties. Assisted optimization approaches may help engineers to select a subset of these models (a.k.a. representative models, or RMs for short), which is used in computational flow simulations in replacement of the original...

The visualization community has been done some efforts to construct a set of heuristics focused on the qualitative evaluation of a visualization (including usability issues, but not limited to them), which could be used in Heuristic Evaluations (HE). Despite these efforts, we could not find a consolidated (i.e. solid) set of visualization heuristic...

Visualization can help users to analyze multidimensional datasets and make better decisions related to them. The current literature presents a set of multidimensional data visualization techniques that deal with discrete variables, continuous ones, or both. Recently, the heatmap matrix was proposed as an alternative for visualizing multidimensional...

Petroleum exploration activities demand the creation of lots of models to represent the uncertainties of a given reservoir, aiming to guide decision-making regarding exploration strategies. As part of these activities, a data assimilation process may refine the model set and discard models that do not honor the history data of the reservoir, given...

Matrix reordering is an Information Visualization topic that aims to study how to reveal information hidden within matrix-based visualizations, through appropriate reordering of its rows and columns. Considering the plethora of algorithms currently available to perform this task, and the set of matrix patterns presented in the visualization literat...

Analysts may use matrix-based visualizations (such as heatmaps) to reveal patterns of a dataset with the help of reordering algorithms that permute matrix rows and columns properly. One of these algorithms is Polar Sort, a pattern-focused reordering method that uses a multidimensional projection technique – Classical MDS – to reveal Band and Circum...

This paper summarizes twelve years of visualization research at the Software Engineering and Information Systems Laboratory (SEIS), located at the University of Campinas. This research comprises theoretical and applied research in visualization and embraces themes such as the development of matrix reordering algorithms, the creation of heuristics f...

Matrix reordering techniques are essential to reveal patterns in tabular visualizations (such as heatmaps). Polar Sort is a state-of-the-art, pattern-focused reordering method that uses a multidimensional projection technique – Classical MDS – to reveal Band and Circumplex patterns in reorderable matrices. However, Polar Sort is not scalable due to...

The Internet gives vendors an easy way to set up shop for electronic commerce throughout the world. However, lack of consumer trust is a critical impediment to the success of e-commerce since users avoid systems they do not trust. In this paper we present the outcome of a literature review in which we investigated personal aspects that impact the s...

Heuristic Evaluation (HE) is a well-known method for assessing usability in Human-Computer Interaction. Among Nielsen’s usability heuristics for HE, ”Consistency and standards” heuristic (H4) is related to consistency, a relevant concept for usability. However, the description of this heuristic does not deal with some relevant aspects of the concep...

Matrix reordering algorithms permute rows and columns of an input matrix for unveiling patterns that are hidden due to inappropriate permutations. Most reordering algorithms are not pattern-focused and provide low-quality results for revealing some particular patterns. On the other side, few algorithms focus on revealing specific patterns with high...

Methodologies of oil reservoir development and management demand the creation of a set of reservoir models that represents the uncertainties of a reservoir. This set of uncertainties is often simplified by the use of Representative Models (RMs), i.e., models that represent the full set. Comparison of risk curves (a.k.a. complementary cumulative dis...

Matrix reordering algorithms permute rows and columns of an input matrix for unveiling patterns that are hidden due to inappropriate permutations. Most reordering algorithms are not pattern-focused and provide low-quality results for revealing some particular patterns. On the other side, few algorithms focus on revealing specific patterns with high...

Accessibility evaluation of websites is normally done before its deployment, but there is a lack of accessibility maintenance after website evolution. This chapter hypothesizes that adopting a continuous website accessibility validation process could facilitate accessibility maintenance after each evolution. To this end, the authors adapted an acce...

The project aims to continue the development of the Matrix Reordering Analyser (MRA) by enhancing internal processes of experiment execution and the integration with R Software, in which several seriation algorithms already available on its libraries could be used as matrix reordering algorithms by the MRA.

Accessibility refers to how a product or service is available and how it can be easily accessed by the user. Accessibility has been systematically addressed by the Web Content Accessibility Guidelines (WCAG). On the other hand, usability addresses the issue of how easy and intuitive a product or service is to use. An easy-to-learn method to evaluat...

Providing an overview of an ensemble of oil reservoir models could help users compare and analyze their characteristics. Approaches that show a single model at a time may hamper analysts’ understanding of the whole model set. In this paper, we propose two visualization approaches that show multiple reservoir models, simultaneously and on a single s...

For a course coordinator, the analysis of several students’ transcripts to identify the situation of subjects or students is often an old-fashioned process executed through a textual and numerical approach. This work is part of a larger project aimed at choosing appropriate visual representations to help course coordinators to analyze sets of stude...

This paper presents an extension of the RMFinder technique, previously proposed for scenario reduction within the decision-making process in oil fields. As there are several uncertainties associated with this process, a large number of scenarios should be analyzed so that high-quality production strategies can be defined. Such broad analysis is ver...

The accessibility of the websites is important to ensure the full access of relevant information to people with disabilities. Website evolution impacts the website accessibility, as the amount of accessibility faults in websites tend to increase during this phase. Normally, the accessibility evaluation is done before deployment but there is a lack...

CourseViewer is a software that uses interactive diagrams to assist students, teachers, and course coordinators in analyzing information related to academic transcripts and course curriculum, which are represented as layered directed acyclic graphs of subjects and prerequisites. Recent improvements in the layout of these graphs included edge crossi...

The application of advanced computational resources in the support of environmental management systems has increased in recent decades. The objective of this research is to discover useful knowledge amidst water monitoring data collected between 2005 and 2011, in a specific region of the state of São Paulo in Brazil. The research was performed in t...

The aging of Brazilian population increases the importance of the study of accessibility. Tablets devices are winning the market, and the study of their interfaces for the elderly also an important field of research. However, recent studies have found that the WCAG 2.0 do not fully address this scenario. In order to fill this gap, nine new successf...

This paper presents an extension of the RMFinder technique, previously proposed to identify representative models (RMs) within the decision-making process in oil fields. As there are several uncertainties associated with this decision-making process, a large number of scenarios are supposed to be analyzed, so that high-quality production strategies...

We propose a 2-step interactive approach for solving a project portfolio selection problem as a single-criterium optimization problem. Our approach innovates by using two coordinated charts: an interactive project timeline with drag-and-drop functionalities for project reallocation in time; and an interactive cost and risk chart that combines line...

Reorderable matrices may be used as support for tabular displays such as heatmaps. Matrix reordering algorithms provide an initial permutation of these matrices, which should help to reveal hidden patterns in the dataset in the visual structure. Some of these algorithms directly permute the data matrix, instead of its row- and column-proximity matr...

The distinction between usability and accessibility becomes convoluted as we focus our analysis in the field of HCI. They were originally conceived as separate concepts and there is no clear comparison between them in the literature. Some authors advocate that these are complementary definitions, while others classify accessibility as a sub-clas...

We propose a 2-step interactive approach for solving a project portfolio selection problem as a single-criterium optimization problem. Our approach innovates by using two coordinated charts: an interactive project timeline with drag-and-drop functionalities for project reallocation in time; and an interactive cost and risk chart that combines a lin...

Characterization of dredged material and monitoring of disposal areas generate a large amount of data hard to interpret due to the necessity of compilation and comparison of an extensive number of samples from different locations over long period under the influence of multiple environmental parameters. Our goal is to test the feasibility of VisSed...

Characterization of dredged material and monitoring of disposal areas generate a large amount of data hard to interpret due to the necessity of compilation and comparison of an extensive number of samples from different locations over long period under the influence of multiple environmental parameters. Our goal is to test the feasibility of VisSed...

Reorganization of rows and columns of a matrix does not modify data but may ease or impair visual analysis of data similarities in this structure, according to Gestalt spatial proximity laws. However, there are a factorial number of permutations of rows and columns. Matrix reordering algorithms, such as 2D sort and Sugiyama-based reordering, permut...

Visualização de Informação (InfoVis) visa facilitar o processo de obtenção e entendimento de informação a partir da análise visual de conjuntos de dados, feita por usuários, auxiliada pelo uso de recursos computacionais. Baseada na interação dos usuários com representações visuais dos dados, essa área recebe diversas influências de Interfaces Human...

Among the various forms of action that promote sustainability, technological innovation can be considered one of the most important. This paper applied data mining techniques to discover knowledge in the field of water quality monitoring data, providing useful and relevant support for decision-making in environmental management systems. At the curr...

Learning Management Systems (LMS) may use Information Visualization techniques and concepts for presenting their large amounts of data, in order to ease the monitoring and analysis of students learning process problems. Nonetheless, the generally adopted approaches are based on presenting data obtained by predefined database queries only, which doe...

Students, teachers and coordinators of degree programs need to access frequently information about program courses, such as credits and prerequisites, and students' course histories. This information is generally available only in a textual format, which may hamper people to make overview analyses of these histories and of program catalogs. In orde...

This paper proposes the use of visualization techniques and data mining in knowledge discovery in the field of data for monitoring water quality. At this stage of research, we discuss some visualization techniques to represent and identify patterns of behavior in these data. For this study, we selected, preprocessed and transformed a large set of d...

This paper presents an approach for using interactive visual data representation in the field of environmental monitoring. Monitoring programs of dredged material disposition areas generates lots of spreadsheets, each one containing thousands of data necessary for decision making. This paper proposes using Information Visualization techniques for e...

Learning management systems (LMSs) store different kinds of e-learning related data, whose analysis is important for monitoring students' learning processes and for helping detection of potential problems on these processes. Different researches apply information visualization concepts and techniques for graphically and interactively presenting LMS...

The development of flexible, reusable and interoperable LMSs has increasingly attracted the attention of the e-learning community. Considering these issues, the TIDIA-Ae project has been proposing a component-based solution for LMSs development. This article presents a development case study according to the TIDIA-Ae's component-based architecture,...

One of the grand challenges in Computer Science research in Brazil for the years 2006 to 2016 is the challenge of management of information over massive volumes of data. This paper aims to present how the objectives of Information Visualization field are close to the objectives of this challenge, detailing the data visualization process and exempli...

The objective of the present case study is the validation of the Architecture and Development Process definitions used within the TIDIA-Ae Project, as exemplified in the development of the Portfolio tool. In this way, the main results obtained in the development process of the Portfolio tool, the solutions adopted for the open issues encountered in...

Content-Based Image Retrieval (CBIR) presents several chal-lenges and has been subject to extensive research from many domains, such as image processing or database systems. Database researchers are concerned with indexing and query-ing, whereas image processing experts worry about extract-ing appropriate image descriptors. Comparatively little wor...

Students, teachers and coordinators of degree programs need to access frequently information about program courses, such as credits and prerequisites, and students' course histories. This information is generally available only in a textual format, which may hamper people to make overview analyses of these histories and of program catalogs. In orde...