Ensuring the readability and comprehension of source code is key for effective software maintenance and evolution, particularly in tasks involving bug fixing, refactoring, and optimization. Previous studies highlight that challenges in maintenance and the emergence of certain bugs can be traced back to small code fragments called "Atoms of Confusion" (AC). While initial investigations identified these snippets in C++ code bases, subsequent studies have identified analogous structures in languages such as Java. Although numerous studies have delved into observing ACs in Java projects, there is a lack of studies focused on the Android ecosystem. This paper aims to address this gap by constructing a comprehensive dataset, which catalogs ACs and assesses their prevalence in the Android Open Source Project (AOSP). After analyzing over 125,000 source code files across 370 Git repositories, our findings reveal that more than 30% of Java files within the AOSP contain at least one AC, totaling over 320,000 recorded instances. This equates to one AC for approximately every 91 lines of code. Particularly, this dataset can be used to support further studies on shedding light on the ACs prevalence in the Android ecosystem, alongside their relation with traditional object-oriented software metrics (e.g., size, complexity, cohesion, and coupling), also recorded in the dataset. Using this dataset, researchers may provide valuable insights for developers and software engineers, emphasizing the need for strategies to mitigate the possible impact of ACs on software maintenance.

Game-Based Learning has already demonstrated its virtues and challenges in Computing education in several disciplines. In this paper, we present a serious game designed to teach Computer Network concepts using a 3D virtual environment and an augmented reality mobile application. The game aims to enhance active learning and collaboration among students while reinforcing their understanding of the subject matter. The game involves group work, where students must solve logical puzzles and find clues related to TCP, UDP, IP addressing, and network routing. We evaluated the students' experiences with the game using the MEEGA+ instrument in both remote and in-person scenarios with a total of 81 students, having positive feedback in both scenarios. The remote scenario presented challenges related to technical difficulties and a lack of face-to-face interaction. In contrast, the in-person scenario received complaints about the game's visual design. This study demonstrates the potential of serious games for teaching Computer Network concepts, highlighting the need for additional support in remote scenarios to maintain student engagement and collaboration.

Software comprehension is essential to improve understanding and avoid mistakes in the software development lifecycle. Code confusion occurs when a developer and the computer reach different interpretations about the behavior of the same piece of code. Such pieces of code can be represented as small and isolated code patterns called Atoms of Confusion (ACs). In this study, we empirically investigated the effects of ACs in the software development lifecycle of 21 open-source Java projects. We built a dataset linking more than 8,000 commits, 4,000 reported issues, and 7,000 ACs from the subject projects. Our findings showed a positive correlation between the number of ACs and the number of reported bugs and improvements. We also investigated changes in commits, looking forward to gathering a better understanding of in what context ACs are removed. As each commit is linked to at least one reported issue (e.g., bug and improvement), we were able to compare the ratio of ACs removal regarding each kind of commit and use it as a proxy to indicate whether ACs are likely to be the cause behind a reported issue. We found a higher ratio of removed ACs in bug-fix and improvement commits than in the other kind of commits (task, sub-task, new feature, wish, and test) for 14 of the 19 studied projects, which had ACs removed in commits. Finally, to support our quantitative results, we conducted a qualitative analysis to understand better how often atoms of confusion contributed to the occurrence of a bug or improvement. We inspected ACs removed in these types of commits with up to ten lines removed, analyzing the source code, messages of each involved commit, and the title, description, and comments of related Jira issues. Out of a universe of 8,641 commits from 21 analyzed projects, 391 removed ACs. Among them, 53 met the condition for our qualitative analysis. In 7 of these commits, 9 removed ACs were likely to contributed directly to the occurrence of a bug or improvement. To the best of our knowledge, our research is the first to investigate the connection between Atoms of Confusion and the source of bugs or the cause of improvements in Java projects.

Video games have become an important aspect of modern culture, especially with the widespread use of mobile devices. Thus, it is important that video games are accessible to all people, but colorblind players are still affected by the use of colors in game interfaces. Some challenges of developing chromatically accessible games are the limited availability of colorblind test subjects and the importance of identifying and considering accessibility threats even in the early stages of development. Thus, digital simulations emerge as possible tools to increase accessibility and awareness. In this paper, we conducted three empirical studies that seek to verify the relationship between the identification of color accessibility problems by people with typical color vision using simulations and people with color blindness, in the context of mobile games. Results indicate concrete uses in which color blindness simulations give advantages to developers with typical vision in identifying chromatic accessibility issues in their games. Additionally, we discuss different possibilities for incorporating simulation tools, accessibility guidelines, and colorblind user participation into a realistic game design life cycle. We also discuss how the incorporation of simulation tools could be beneficial to foment the discussion of accessibility in game design studios.

Program comprehension is a fundamental activity in software maintenance and evolution, impacting several tasks such as bug fixing, code reuse, and implementation of new features. The Atom of Confusion (AC) is considered the smallest piece of code that can confuse programmers, difficulting the correct understanding of the source code under consideration. Previous studies have shown that these atoms can significantly impact the presence of bugs in C++ projects and increase the time and effort to code understanding in C++ and Java programs. To gather more evidence about the diffusion of ACs in the Java ecosystem, we conduct a study to analyze the prevalence, co-occurrences (at the class level), and evolution of ACs in 27 long-lived Java libraries. To support our investigation, we developed an ACs automatic search tool, which found 11.404 occurrences in the studied libraries. The Conditional Operator and Logic as Control Flow ACs were the most prevalent among the 10 types of ACs assessed. Our findings show that Conditional Operator and Logic as Control Flow were more likely to co-occur in the same class. Finally, we observed that the prevalence of ACs did not decrease over time. On the contrary, in 13 libraries, the presence grew proportionally more than the size of the library in lines of code. Furthermore, in 15 libraries, the fraction of Java classes containing at least one AC also increases over time.

Software Engineering (SE) education presents many challenges, especially related to hands-on activities that aim to improve practical skills and competencies to solve real-world problems. Some new Learning Approaches, such as Flipped Classroom (FC), emerged and can improve learning processes in this scenario. This doctoral work explores the Flipped Classrooms ideas, identifies challenges, and proposes a tool for reducing them, thus contributing to improved software engineering teaching research. Furthermore, the study aims to combine Adaptive Learning and Flipped Classroom approaches to offer study guides personalization and positively impact SE students’ learning during outside classroom studies.

BACKGROUND AND MOTIVATION: The world population is living longer than ever before, Ambient Assisted Living (AAL) research try to ensure people are ageing well by using digital and physical technologies. The development of AAL platforms presents several challenges (e.g., sensor data integration, device interoperability). Many requirements for AAL platforms can be met by using the Internet of Things (IoT) and Cloud Computing paradigm standards. METHODOLOGY: In this paper, we conducted a systematic mapping of the literature on AAL platforms to investigate the correlation between these three paradigms. We focused on AAL platforms that use IoT and Cloud Computing concepts to meet their requirements. Our primary research question is "What are the requirements of AAL platforms in the IoT Era and their relationship with IoT standards?". We defined as the scope of our systematic mapping the primary studies about AAL platforms published between 2013 to 2017, and we used seven indexed electronic databases. RESULTS: We obtained 35 papers whose AAL platforms developed using IoT or Cloud Computing standards. We then analyse and correlate the requirements, architectures, and evaluation types presented by these platforms. We found patterns by connecting specific requirements with platform design. We believe these results assist AAL developers and architectural designers in the creation of new AAL platforms and applications.

In Computer Science programs, teaching the subject of Distributed Systems (DS) presents many challenges, especially related to the students’ prior knowledge. Some new Learning Approaches emerged and can aid to improve learning processes in this scenario, such as Flipped Classroom and Adaptive Learning. Using these approaches together enables students to explore content in a personalised way while meeting the professor-defined course objectives. In this context, our work presents a study of the integration of Flipped Classes with Adaptive Learning techniques for supporting the learning of Distributed Systems. We developed a tool to assist in the creation and generation of personalised study guides. To evaluate it, we conducted a Case Study mixing quantitative and qualitative analysis with 26 students during an entire semester of a DS course. The results indicate most students positively evaluated our approach and felt motivated in following new flipped classes with personalised study guides.

In the Internet of Things paradigm, the total number of interconnected smart objects tends to increase in elevate rates in the next years, creating an overload of objects to be controlled and configured by the users themselves. Alternatively, context-aware discovery services have potential to minimize this problem by applying rules to determine which smart objects are more suitable for users, at a certain time. To help acquiring the contextual information, there are several context acquisition middlewares, e.g., LoCCAM, that creates abstraction layers which provides application a simple way to define and apply contextual discovery rules. This work proposes the CoAP-CTX, an extension of the built-in discovery service present in the CoAP protocol. Our approach aims to provide support to a context-aware discovery service of smart objects. The CoAP-CTX matches users' interest and context with the smart objects state data to retrieve most relevant smart objects to the user in this instant. Additionally, smart objects that are not of the user's interest go into an idle state, optimizing the network and battery usage. Experiments have shown that CoAP-CTX can decrease the total number of messages up to 80% in scenarios where a large number smart objects are presents in a generic environment, like working buildings. The overhead of the discovery latency shows a maximum discovery time increase of 1.5 seconds.

Location-Based Mobile Games (LBMGs) are a subclass of pervasive games that make use of location technologies to consider the players' geographic position in the game rules and mechanics. This research presents LEGaL, a language to model and represent the structure and multimedia contents (e.g., video, audio, 3D objects, etc.) of LBMGs. LEGaL is an extension of NCL (Nested Context Language) that allows the modelling and representation of mission-based games by supporting spatial and temporal relationships between game elements.

X-ray view can be defined as the ability one has to see through real surfaces. Although this skill is often associated with superheroes and medical examination, there are several researches conducted to employ X-ray view in numerous applications. However, the generation of X-ray visualization includes numerous challenges regarding occlusion, realistic appearance, and depth perception.

This paper presents an approach for modelling and generating Context-Aware and Mobile (CAM) applications based on (i) Model-Driven Engineering and (ii) context acquisition middleware concepts. Our approach allows software engineers to build CAM applications by modelling contextual information and rule-based behaviour on a visual notation. These graphical models are transformed into an Android-based code, targeted for a context-aware middleware called LoCCAM, which encapsulates device sensors access. An initial user evaluation conducted with a group of fourteen computer science volunteers was implemented and indicates time reduction gains in the middleware configuration process and that the complexity in the writing of contextual behaviour of applications is also decreased.

Geology is a fundamentally important natural science that explores resources such as minerals, water, fossil fuels and many others. Geology's field of knowledge also has social relevance in preventing natural disasters. Because of these features, geology is important not only as a science itself but in several other areas, such as engineering, biology, and oceanography. In this context of a natural science, the field trips are an essential activity for learning. During these classes, students need to make notes, take photos and perfom measurements using different equipment, and pay attention to the teacher's instructions. This paper presents the specification, development and use of a mobile application to enhance and aid in geology field trips called Geomóvel. A case study was performed that exhibited good acceptance of the application by the students, who stated that the major benefits were ease of use and practicality of annotation in multiple formats. The application also enables data to be exported to Google Earth such that the teacher can analyze the data recorded in the case study.

The evolution of mobile technologies allows the emerging of ubiquitous systems, able to anticipate user needs and to seamlessly adapt to context changes. These systems present the problem of dynamic adaptation in a highly distributed, heterogeneous and volatile environment, since it may be difficult to collect and process context information from distributed unknown sources. In order to facilitate the development of such systems, this paper extends an existing coordination framework based on tuple spaces, aiming at the management of distributed information. Hence, a decentralized coordination framework was created, offering primitives to developers to create ubiquitous systems able to interact and cooperate in scenarios of total decentralization. This paper reports some experimental results obtained in a testbed of smartphones and tablets which demonstrate the practical feasibility of our approach and pointed out how our solution can grant context data dissemination in ad hoc and infrastructured networks.

Software Product Lines (SPLs) have evolved and gained attention as one of the most promising approaches for software reuse. Feature models are the main technique to represent domain variability in SPLs. However, there are other domain aspects, besides variability, which cannot be expressed in a feature model. Also, these diagrams were not designed to facilitate information retrieval, interoperability and inference. In contrast, ontologies seem to be the best solution to meet these requirements. Therefore, this work presents an approach for semantic enrichment of SPLs using ontologies. Our proposal provides methods to add domain information besides variability description, and a top-ontology that specifies generic concepts and relations in an SPL, working as a guide model for information addition. The proposed approach reuses the existing SPL feature model, adding semantic descriptions in a less intrusive way than modifying the feature model notation.

SUMMARY Complex scientific experiments have a growing demand for computational resources, which are expensive to be acquired and maintained. Grid computing has emerged as the mainstream technology to solve this issue. Grids are also adequate for the execution of scientific workflows because they allow the use of heterogeneous and distributed resources. In spite of the progress in grid technology, there are challenges to overcome in workflow scheduling. For instance, centralized scheduling solutions may lead to performance degradation and to problems with scalability. Some scheduling approaches are partially distributed, keeping a few centralized components that may become bottlenecks. Other distributed solutions have a lack of flexibility in the definition of workflows, in which only the use of tasks as steps in the workflow is permitted not high level services. In this work, we present P2PScheMe, a scheduling mechanism for peer‐to‐peer execution of workflows based on the invocation of grid services. The proposal considers information regarding grid execution environment in order to allow workflow scheduling adaptation. This adaptation is performed according to user requirements of quality of service. In this paper, we describe how P2PScheMe works and provides a comparative analysis with existing solutions. Copyright © 2011 John Wiley & Sons, Ltd.

In the recent years, photo context metadata (e.g.,date, GPS coordinates) have been proved to be useful in the management of personal photos. However, these metadata are still poorly considered in photo retrieving systems. In order to overcome this limitation, we propose an approach to incorporate contextual metadata in a keyword-based photo retrieval process.We use metadata about the photo shot context (address location, nearby objects, season, light status...) to generate a bag of words for indexing each photo. We extend the Vector Space Model in order to transform these shot context words into document-vector terms. In addition, spatial reasoning and geographical ontologies are used to infer new indexing terms. This facilitates the query-document matching process and also allows performing semantic comparison between the query terms and photo annotations.

This paper presents an approach for incorporating contextual metadata in a keyword-based photo retrieval process. We use our mobile annotation system PhotoMap in order to create metadata describing the photo shoot context (e.g., street address, nearby objects, season, lighting, nearby people...). These metadata are then used to generate a set of stamped words for indexing each photo. We adapt the Vector Space Model (VSM) in order to transform these shoot context words into document-vector terms. Furthermore, spatial reasoning is used for inferring new potential indexing terms. We define methods for weighting those terms and for handling a query matching. We also detail retrieval experiments carried out by using PhotoMap and Flickr geotagged photos. We illustrate the advantages of using Wikipedia georeferenced objects for indexing photos.