This research article assesses the concepts of Computational Thinking (CT) as applied in basic education. Although widely used in K12 education, many articles indicate a lack of uniformity in the conceptualization of CT. CT is defined as the systematic problem-solving ability based on algorithmic processes. It is seen as crucial for stimulating interest and diversity in STEM careers. Effective CT teaching requires precise conceptualization and appropriate teaching techniques. With the world's increasing digitization, CT is considered as fundamental as reading or math skills and should be taught from K12 education. This article reports a systematic mapping of CT con-cepts applied in K12 activities, reflecting on the chosen activities and teaching techniques. Despite some articles highlighting the unclear definition of CT, there is a notable agreement on its key concepts. The study used the IEEEXplore database, analyzing primary articles from 2019–2023. The findings reveal a high degree of similarity in CT concepts, indicating a trend towards standardization. A catalog of frequently cited activities used to teach CT is presented, aiding teachers in introducing CT in their classes. This study supports the development of teaching policies and initiatives. contributing to STEM interest and diversity.

Mathematics is a crucial skill in modern society, enhancing problem-solving abilities across various fields, from medicine to philosophy. Its concepts underpin major information systems, including machine learning and mobile applications. Nonetheless, many countries experience significant gaps in students' understanding of fundamental mathematical concepts, leading to widespread math anxiety, particularly concerning fractions. Moreover, numerous studies indicate that digital games positively influence learning outcomes by providing an engaging teaching method. To understand how existing digital games have been used to teach fractions, we conducted a Systematic Literature Review (SLR) that explores digital games that support teaching fractions and examines how they have been integrated into teaching strategies, including how their pedagogical effectiveness is assessed. Our findings underscore the need for more tools compatible with Learning Management Systems (LMS) and improved accessibility to the games/tools mentioned in the literature. Additionally, there is an urgent need to develop metrics for evaluating the effectiveness of game-based learning tools for fractions.

The Electrical Engineering undergraduate program of the Escola Politécnica of the Universidade de São Paulo has created an alternative innovative curriculum path for its freshmen students in 2024. The Competency-based Path emphasizes the development of competencies and skills for the unprecedented technological advancements that necessitate a holistic education for future electrical engineers, preparing them with practical skills for real-world challenges. The program was designed using an innovative methodology and centers around semester-long or year-long integrative projects. These projects bridge the gap between theory and practice, as students deal with real-world challenges while fostering social responsibility.

This research full paper presents a systematic review exploring methods and pedagogical strategies utilized for digitally including adult education students through computer-assisted collaborative activities. Youth and adult education faces significant disparities along the globe, with low enrollment rates in many countries as highlighted in the UNESCO's$5^{th}$Global Report. Whenever we consider the$4^{th}$United Nations' Sustainable Development Goal for 2030, education aims for inclusion and lifelong learning opportunities. With the aim of investigating the literature about existing computer-assisted collaborative methods and strategies for digital inclusion of youth and adults, we conduct a systematic literature review on the theme. Findings reveal a scarcity of works tailored to adult education, especially in developing nations, even with the inclusion of Brazilian and South African knowledge repositories to broaden the scope. Collaboration emerges as a prevalent strategy, often alongside other methodologies. Notably, mobile devices are widely utilized due to their accessibility, and social networks and virtual learning environments play significant roles. However, the integration of computational thinking and artificial intelligence for digital inclusion is still in its infancy. Overall, digitally including adult learners is crucial for fostering inclusive education and enhancing opportunities for marginalized populations.

Question Answering systems based on large language models are widely employed today, benefiting from continuous enhancements and improved performance. The legal domain has become a particularly active focus for Question Answering systems, given its complexity and social importance. This paper offers a discussion on how larger and smaller language models can be used to build a legal document-based Question Answering system. We present a novel model, named Cocoruta, generated by fine-tuning with a corpus of legal documents. In addition, we examine five LLMs as they answer questions related to the legal aspects of a specific domain – the Blue Amazon, a region of particular interest involving environmental issues. The results suggest that while LLMs are not yet of sufficient quality for use as core in legal context Question Answering systems, fine-tuning on specialized corpora imparts a beneficial bias to their legal discourse. Despite having fewer parameters, the Cocoruta model competes well with larger LLMs in this aspect.

Computational thinking has become an essential skill nowadays. Many educational institutions around the world have adopted computational thinking as an elementary or complementary subject in their teaching schedules. One of the approaches that is efficient in teaching and learning computational thinking has been visual programming. However, like other applications used daily, visual programming tools can be a limiting factor for the blind in learning computational thinking. This work aims to present the iVProg4all, an accessible visual programming system based on forms. A preliminary study was carried out to test the usability of iVProg4all and accessibility with a blind user. The results show that, although some usability issues need to be fixed, the system proved accessible for blind people.

The global pandemic of Covid-19 has accelerated the use of computer technology applications in our daily lives, leading to an increased use of web-based learning management systems (LMS). Consequently, a larger volume of data related to students and their interactions with LMS has been produced and efforts has been directed to identify relevant information from such data to support the learning process. However, this task has become increasingly challenging by the diverse range of social, cultural and economic backgrounds of students, as well as their varying learning styles. Thus, this work describes a systematic mapping of the literature considering primary studies to identify the different strategies employed to predict students' outcome, such as Educational Data Mining (EDM) and Learning Analytics (LA). The main research question was: “what is the current context of research related to the data-driven prediction of the students' performance”. We analyzed 315 studies from IEEExplore and ACM Digital Library, selecting 85 studies for full reading. As a conclusion, predicting students' performance to improve education is an alive and open problem, yet students' performance can be predicted. Also, only a few works apply information resulting from educational data mining back to the learning environment to improve the learning process. A subset of the acquired data can provide subsidy to improve the learning process, for this reason we call this as relevant data, and after processing, relevant information. We define relevant information any information, feature or pattern that was successfully used to predict students' outcome. Another result is the finding of studies that use predicting tools unsuitable to quantify how data is relevant.

Current research in natural language processing is highly dependent on carefully produced corpora. Most existing resources focus on English; some resources focus on languages such as Chinese and French; few resources deal with more than one language. This paper presents the Pirá dataset, a large set of questions and answers about the ocean and the Brazilian coast both in Portuguese and English. Pirá is, to the best of our knowledge, the first QA dataset with supporting texts in Portuguese, and, perhaps more importantly, the first bilingual QA dataset that includes this language. The Pirá dataset consists of 2261 properly curated question/answer (QA) sets in both languages. The QA sets were manually created based on two corpora: abstracts related to the Brazilian coast and excerpts of United Nation reports about the ocean. The QA sets were validated in a peer-review process with the dataset contributors. We discuss some of the advantages as well as limitations of Pirá, as this new resource can support a set of tasks in NLP such as question-answering, information retrieval, and machine translation.

This full paper of Research Category presents the main results of a systematic review of the literature about the use of computer games in science, technology, engineering, and mathematics (STEM) courses. The concept of lifelong learning has often been encouraged in literature. However, it also reports students facing difficulties in exact sciences since elementary school: a significant challenge to overcome. Among the reasons for such difficulties are demotivation, disinterest, learning difficulties, and even the use of outdated teaching-learning methods. In an attempt to improve the relationship between students and exact sciences, schools are expanding the use of information technologies to offer the students interactive environments in order to enrich their classes. In this context, characteristics of digital games appear as a didactic resource that can benefit the students' learning process. If properly used, digital games can stimulate memory, creativity, socialization, and also incite curiosity. Due to the ease young students have with games and considering the benefits mentioned above, many institutions have been investing in digital games (or environments with some of their characteristics). However, these games can generate compulsive behaviors (WHO classified such disorders in 2018), and it is worth noticing that many articles reporting the use of games in education focus mainly on its acceptance instead of its teaching capabilities. In this article, we report the main findings, such as that technology is the area with the highest concentration of digital games. It is also observed that different guiding theories appear, such as those with a constructivist tendency. Among the arguments for using games stand out: the gain in cognitive skills, the possibility of using simulations, and the ease in understanding complex themes. The methods of didactic-pedagogical evaluation mostly used are questionnaires of acceptance or the student's perception. This review highlights the potential of digital games to promote learning. However, these games should not be focused solely on their ludic aspect, as they have a different purpose from regular games. Active methodologies mediated by information and communication technologies can make class more engaging as students actively participate in the construction of student learning.

The comprehension of algorithms is becoming essential and programming, not rarely, has being introduced since elementary school. Nevertheless, the acquisition of programming skills is not an easy task. This fact is corroborated by the literature that report alarming failure and dropout rates in CS0 (Introduction to Computer Science) courses. On the other hand, forecasts about the demand for software developers indicate exponential growth over the next decade.In this context, reducing the cognitive workload for learners is desirable. For instance, the integration of a web-based environment with some visual programming tool and automatic assessment could benefit learners.The adoption of a unique environment where the students could learn how to solve problems using algorithms and receive immediate feedback may reduce the slope of the learning curve. Moreover, the possibility of using the same tool to communicate with their teachers and colleagues can positively affect their learning.Also, the visual programming paradigm can reduce the need for memorization of a programming language syntax. It allows learners to focus their attention on solving the problem algorithmically.There are several tools that provide automated assessment evaluation. Some of these can be used with Web browsers, but very few of them can be integrated with a Learning Management System (LMS). In this workshop, we will discuss two of these systems that are distributed as free software: the Virtual Programming Laboratory (VPL) and the iVProgH/iAssign solutions. They can all be integrated with the Moodle platform.Since VPL demands an extra installation of the jail server (to run students solutions) and works with traditional programming languages, the focus will be over iVProgH/iAssign. The iVProgH/iAssign solution implements the Visual Programming Paradigm. iVProgH is implemented in HTML, CSS and JavaScript, sparing the use of a security environment to separated compilation, as VPL demands.

This Research Full Paper presents a literature review about overcoming accessibility barriers for People with Severe vision impairment in Web-based Learning Environments.People with vision impairment face several barriers while interacting with web-based environments.Among them, one can cite the lack of suitability of these environments for the use of screen readers, e.g. if the description of the environment elements are not readable by the screen reader.These barriers are also present in web-based learning environments. In this work we present, through a literature review, the most common accessibility barriers faced by people with vision impairment while interacting with web-based learning environments. In addition, we propose solutions that can mitigate this problem, allowing broad access to distance education environments and a better learning experience with them.

This innovative practice full paper presents a Metaphorical Debugger Model (JAD) to support deaf and hearing impaired in the process of learning how to program in Java. In Brazil, 9.7 million people are deaf or hearing impaired (DHI). DHI people usually face several barriers to get proper education. During a series of Java classes conducted by our team, we verified that these difficulties were also related to the use of software that is not tailored for their impairment. We also saw that DHI students encountered many problems while developing and evolving their codes using the traditional tools, for instance, visual signs to perform tasks, can be difficult to understand, in addition, the high degree of abstraction required for the programming logic, can be an accessibility barrier for them. Thus, we decided to propose JAD aiming to provide accessible debugging for DHI. The JAD uses the concept of metaphorical interfaces, adopting appropriate symbols and signs borrowed from traffic to aid in the process of code debugging and evolution. In this paper, we present some user studies with JAD. The results suggest that Java programmers, DHI e non-DHI, had similar performance in task related to software evolution when JAD was used.

In recent years, the use of wireless devices has experienced huge grown, mainly due to the decrease in cost, size and energy consumption. Research in the Internet of Things have concentrated their efforts on how to monitor these devices taking into account both scalability and efficiency while searching and updating continuously device information. In order to do that, current alternatives combine a widely recognized method, the data aggregation, and a widely adopted distributed structure, called Distributed Hash Table, which form groups of devices, saving energy by minimizing the number of transmissions. However, scalability is still a key challenge when the group comprises a large number of devices. In this paper, we propose a scalable architecture that creates agents to distribute the responsibility of managing groups and the interaction among them, such as merging and splitting, and shares the data aggregation with the devices of group frontier. Experimental results showed the viability of adopting this architecture if compared to the most widely used current approaches.

Dynamic lectures are collaborative settings in which learners and educators interact with each other and among them to produce, learn, and consolidate knowledge. To take part into collaborative settings, individuals must be able to communicate with others, be aware of the artifacts used and of the objects of interest, among others. On their foundation, these requirements depend on motor and cognitive-related abilities such as arm movement, perception, recognition, and memorization. Impairments may influence these abilities and consequently pose challenges to the participation in collaborative settings. To the best of our knowledge, there is not a guide, a method nor a framework to orient anyone who wants to analyze the scenario of collaborative settings in order to create conditions for the inclusion of individual in such activities. In this context, this paper presents the Colab4All - Collaboration for All, a framework created to support the analysis of collaborative settings involving people with impairments. The framework uses the well known Human Processor Model with two complementary objectives: first, to derive questions that must be asked to support the analysis previously mentioned, and then to combine these questions with a collaboration model in order to establish the way potential challenges can be addressed. In order to test the proposed framework, we used it to orient a research on the inclusion of individuals with blindness in a class activity based on graphical notations. The results of such research were tested in a real setting and presented promising results. We consider that the framework proposed in this work is a first step to orient research, derive collaborative and inclusive models, and to define requirements for technology that supports such collaborative settings involving people with impairments.

Context-aware systems are capable of perceiving the physical environment where they are deployed and adapt their behavior accordingly. Multiagent systems based on the BDI architecture can be used to process contextual information in the form of beliefs. Contextual information can be divided and structured in the form of information domains. Information and experience sharing enables a single agent to receive data on different information domains from another agent. In this scenario, establishing a trust model between agents can take into account the relative perceptions each agent has of the others, as well as different trust degrees for different information domains. The objective of this work is to adapt an epistemic model to be used by agents with their belief revision in order to establish a mechanism of domain-specific relative trust attribution. Such mechanism will allow for each agent to possess different trust degrees associated with other agents regarding different information domains.

The increasing number of moving vehicles along roads and the lack of supporting infrastructure is a wellestablished problem. Major consequences are augmenting of traffic jams, accidents, fuel consumption and pollution. Vehicular Ad hoc NETworks (VANETs) represent opportunities to deal with the aforementioned problems. In VANETS, efficiency and safety to applications are provided using communication support. In efficiency applications, each vehicle is aware of its location. Using this information and communication support, vehicles collaborate to reduce travel time and to improve mobility. In contrast, safety applications aim to reduce or even avoid accidents, and must obey strong timing constraints. In this context, VANETs applications can benefit from Computational Intelligence (CI) and adaptive approaches to implement the required demands. Thus, the contribution of this paper is twofold: $( i)$ we discuss how VANETs can benefit from CI and Artificial Intelligence techniques to make transportation networks more efficient regarding to safety applications, and, $( ii)$ we report our current work and new directions in the development of efficiency applications to VANETs using adaptation and CI techniques.

E-learning is a modality of education that has been growing all over the world. However, in computing and engineering education programs, the frequent use of graphical representations creates obstacles to the inclusion of visually impaired learners. Besides, many of the strategies and tools used in traditional lectures are not appropriated in e-learning lectures because of the distance among participants. In this context, this paper presents an evaluation of learners' perceptions during e-learning lectures on software requirements specification using UML/SysML use case models, as well as their associated learning assessment. Visually impaired and sighted learners attended online lectures in real-time with spatial distance. Participants used an external remote communication tool and some features of Model2gether to communicate and coordinate lecture activities. Model2gether was also used for collaborative real-time interaction with use case models. Learners responded a pre-survey and were interviewed prior to the lectures. After the lectures, learning assessment was twofold: by group work and an exam. Their perceptions were gathered through a post-survey and an interview. The quantitative data was statistically analyzed. The results indicate that, with appropriate tool support, it is possible to include visually impaired learners in e-learning activities based on graphical representations. Moreover, the post-survey indicates that the learners did not recognize their colleagues are sighted or not while collaborating using Model2gether.

Information and Communication Technologies (ICT) are playing an increasing role in our daily lives and it is changing knowledge delivering. For engineers and related careers, where new trends and technologies are delivery continuously, having professional success depends on being updated with them. By adopting web-based learning so that both, students and professionals may accelerate such achievement. Nevertheless, the dropout rate of courses delivered by the World Wide Web (Web) used to be very high, mainly for the ones delivered by MOOC (Massive Open Online Courses). The reasons for that rely on several causes, mostly the ones related to the difficulty of students adapting themselves to the routine of individual studies. Therefore, finding strategies to deal with this difficulty may mitigate dropout rate in web-based learning. In this paper, we describe a systematic review of the literature to find evidences for the relevance of proposing a model to support web-based courses and foster collaboration between pairs as a mean to address the top three problems identified as reasons for the high dropout in distance learning. We also sketch iMPaCTS, the resulting model.

Software processes, as software products, are variable across projects and thus a one-size-fits-all approach does not work out for development processes. We propose Meduse, an approach for tailoring development processes according to project needs. Such an approach, which is based on software product line and method engineering techniques, takes into account processes similarities (i.e. commonalities) and differences (i.e. variabilities), as well as reusable process fragments. Having processes tailored on demand according to the project needs shall reduce project risks, rise best practices adoption by the development team, support project planning and budget managing, among other benefits.

This paper presents iPlan, a model to implement a system to support the creation of lesson plans. It was the result of a systematic review on tools that help teachers on authoring courses that must be delivered through the World Wide Web (Web). The iPlan system aims to simplify teachers' workload while preparing lessons that will be available online in some Learning Management System (LMS). It will provide authoring tools that enable teachers to create and edit lesson plans based on Pedagogical Patterns. By Pedagogical Patterns we mean tested lesson plans or roadmap lessons. Teachers will be empowered with means to create custom patterns, as well. The main feature that distinguishes this study from previous researches is the integrated approach with LMS, lesson plans and pedagogical patterns. In order to allow teachers to store new pedagogical patterns, iPlan uses iRepository, a repository of educational digital content which is also integrated with Moodle. iPlan is being developed for Moodle environment and will be distributed under the GNU Public License (GPL).

Nowadays, computer programming and logical thinking skills have been proposed as a fundamental knowledge, even to young learners. On one hand, in undergraduate STEM (Science, Technology, Engineering and Math) courses, the first contact of students with the logic of programming usually results in high failure rates. The literature and experiments conducted by the authors point out that this occurs regardless the adopted programming language. On the other hand, the literature presents some positive results when the paradigm used to introduce the subject is Visual Programming (VP), where the learners use icons to build their programs. This approach is successful even with young learners. In this context, a relevant question is whether, and how, the Visual Programming can help learners to understand a traditional textual programming language. The proposal of this work is to study differences between visual and traditional programming by analyzing the mental workload of using both paradigms during the introduction of algorithms and basic concepts of programming in the context of an online course of introductory programming. In order to perform such analysis, we adopted the NASA TLX protocol.

Interactive Geometry (IG) is a computational approach to teach geometry using interactive geometric objects. It is based on the learning-by-doing method where the representation and manipulation of geometric spaces can support students to construct their knowledge through experience. Several research findings indicate various benefits of using IG in classroom. Nevertheless, IG software developed to date has been based on the desktop model where the interaction between a user and the IG software occurs through the conventional inputs and outputs methods: keyboard, mouse, and a monitor. Currently, this model is being challenged by the widespread adoption and use of mobile devices. In this scenario before building an IG software that can be effectively used in mobile devices such as smartphones and tablets, where the input is based on touches and movements of fingers and the output is a small screen, there is a need to rethink the interface and what interaction methods should be employed. In response to this need, our paper examines the design and development of a GI application for mobile devices. In this study, we have proposed and implemented an interface and interaction model that is suitable for developing a GI software for mobile devices.

The demand for digital learning content has been increasing in the last years and the advent of the Learning Objects (LO) concept has the goal of mitigating some of the difficulties related to authoring such kind of digital content, by proposing a reusable model and an open metadata standard classifications for them. Nevertheless, digital learning content authoring is often an expensive and time-consuming task that requires many distinct professional skills. One attempt to overcome it is the adoption of Learning Object Repositories (LOR), in order to smooth LO manipulation experiences for teachers and content authors. Some of its keys characteristics are: to promote LO dissemination and reuse to users in a unified spot; and, to serve LO through flexible searches and enforce a metadata standard classification. This paper proposes an innovative repository model to support LOR and their use in web-based courses in the context of an specific LMS, the Moodle environment. The model is flexible, enhances digital content searches and can be fully integrated with an institutional LMS. Moreover, it offers a social environment for peer evaluation and, more important, information about the student performance, resulting in an efficient evaluation of the available contents.

Moodle is a well-known open source system to support teaching and learning through the web. It provides Quiz, a tool for learning assessment, which is also adopted by a large community along the world. Another tool that allows automatic assessment within Moodle is the iAssign package. iAssign provides means for integrating interactive Learning Modules (iLM) to Moodle, empowering it with interactive intense activities concerning specific issues implemented in iLM. However, such tools present some limitations that prevent their users to take more benefit of the question types and iLM such as (i) authoring is not a simple task; (ii) iAssign integrates iLM to Moodle without incorporating Moodle questionnaires; (iii) Quiz database for questions and questionnaires is not integrated to a repository with search and retrieving tools; (iv) in the current version of Moodle, Quiz didn't allows the incorporation or exportation of assessment content that follows the IMS-QTI 2.1 (Question and Test Interoperability) specification. In this paper we address such limitations proposing a generic model and its implementation for the Moodle system.

One of the big challenges that teachers and students face at early stages of CSET (Computer Science, Engineering, and Technology) courses are the difficulties related to teaching and learning algorithms. Usually, such knowledge is presented during introductory programming related disciplines, when students are also presented to some programming language to describe simple algorithms. Therefore, they need to learn not only the new language but also a formal way to describe the solution of problems using that language. This is much different from any formalism they were presented in their previous student's experience. This paper presents iVProg, a system conceived to overcome some of these difficulties by using visual programming. Some experiments were conducted during three years to evaluate students' performance without the system support and with it using different didactic approaches.

Intelligent Tutoring Systems (ITS) provide many features that improve learning and teaching experiences. ITS are usually interactivity-intense and content-specific. Interactivity-intense assignments are recommended for scaffolding learning, while content-specific systems can offer low flexibility regarding its possible pedagogical approaches and its uses by teachers. In order to overcome this limited flexibility, there are systems which let content-specific interactivity aside to provide authoring tools, with which teachers can author intelligent tutored assignments without programming. The generic model proposed herein intends to address this problem providing flexible authoring tools for interactivity-intense assignments with tutoring features, letting teachers benefit from the flexibility of content authoring tools as well as the interactivity usually restricted to content-specific ITS. We introduce an application framework which implements this model, which is available as free software.

The interface is the main mechanism of communication between user and system features. In educational software, successful user interface designs minimize the cognitive load on users, thereby users can direct their efforts to maximize their understanding of the educational concepts being presented. We investigated whether a reduced interface make few cognitive demands on users in comparison to a complete interface. In this context, this research aims at analyzing a reduced and a complete interface of an interactive geometry software, and verify the educational benefits they provide. To this end, we designed the interfaces and carried out an experiment involving 69 undergraduate students. The experimental results indicate that an interface that hides advanced and extraneous features helps novice users to perform slightly better than novice users using a complete interface. After receiving proper training, however, a complete interface makes users more productive than a reduced interface.

The development of good quality educational software is expensive, time-consuming and faces some underlying issues. In order to deal with such issues, many attempts were made, mainly on code reuse. Following a similar approach, the development of an application framework for implementing a family of interactivity-intense educational software called Interactive Learning Modules - iLM is presented. The framework main goal is to reduce development efforts while being part of a Software Product Line - SPL, an innovative technique regarding interactivity-intense educational software. The framework specification is presented by analyzing the common features of existing iLM. Therefore, the resulting component architecture is outlined. Currently, the design phase is finished and the implementation ongoing. Also, its instantiation is planned for an existing iLM, as a proof of concept.

There are different approaches that drive the development and use of educational software, such as Interactive Geometry Systems - IGS and Intelligent Tutoring Systems - ITS. Considering their benefits to teachers and students, these systems may be used to complement each other. The ongoing development of ITS features in an existing IGS called iGeom is presented. First, the limitations of both approaches are listed, describing possible benefits of using them together. Then, the resulting component architecture of the conducted analysis and software design is outlined. The ITS paradigm chosen was Example-tracing Tutors. The current state of research is the tutoring features implementation and planning for testing in classrooms and in distance learning courses.

An important discipline in the basic education of CSET students is related to mathematical functions and associated issues. Therefore, technology advances on building and delivering software to support such subject had been benefited students all over the world. However, most of such software are stand alone systems that don't provide support for their integration to Learning Management Systems - LMS. In this paper we present iGraf - interactive Graphics on the Internet, a new software that provides the basic resources for general-purpose plotting tools, as well as resources that make possible its easy integration with LMS. Moreover, it provides a simple model for authoring and automatic assessment features. Both, authoring and automatic assessment were designed based on a systematic study of the literature related to Calculus and K-12 math courses. In order to produce a proof of concept, it was integrated to Moodle with the iAssign package and some experiments with K-12 math teachers and undergraduate students were conducted. iGraf can be freely downloaded from http://www.matematica.br/igraf.