Paolo Buono

Phishing represents one of the most spread and effective cyber-attacks of our times. Warning messages are commonly employed in email clients to notify users about the possible danger and let them decide on their own. However, the high success rate of phishing attacks shows that the existing warnings are not yet adequate. This study contributes by proposing two novel warning dialogs for email clients that prevent users from immediately accessing the content of phishing emails. Specifically, the first one alerts the users against the potential scam, and the second one also reports explanations about the possible causes of the scam. A comparative between-subjects experiment with 300 participants has been performed. Results show that the proposed warnings better defend users from phishing emails than the warnings at the state-of-the-art. In addition, explanations resulted useful in preventing users from discarding genuine emails where warnings are displayed incorrectly due to misclassification of the email.

Genomics-based diagnostic data (GBDD) are becoming increasingly important for laboratory diagnostics. Due to the large quantity of data and their heterogeneity, GBDD poses a big data challenge. Current analysis tools for GBDD are primarily designed for research and do not meet the requirements of laboratory diagnostics for automation, reliability, transparency, reproducibility, robustness, and accessibility. This makes it difficult for laboratories to use these tools in tests that need to be validated according to regulatory frameworks and to execute tests in a time- and cost-efficient manner. In order to better address these requirements, we propose an event-driven workflow-based architecture as the basis for a processing platform that is highly scalable using container technologies and microservices. A prototype implementation of this approach, called GenomicInsights, has been developed and evaluated to demonstrate its feasibility and suitability for laboratory diagnostics.

Hypergraphs are a generalization of graphs in which edges (hyperedges) can connect more than two vertices-as opposed to ordinary graphs where edges involve only two vertices. Hypergraphs are a fairly common data structure but there is little consensus on how to visualize them. To optimize a hypergraph drawing for readability, we need a layout algorithm. Common graph layout algorithms only consider ordinary graphs and do not take hyperedges into account. We focus on layered hypergraphs, a particular class of hypergraphs that, like layered graphs, assigns every vertex to a layer, and the vertices in a layer are drawn aligned on a linear axis with the axes arranged in parallel. In this paper, we propose a general method to apply layered graph layout algorithms to layered hypergraphs. We introduce six different transformations for layered hypergraphs. The choice of transformation affects the subsequent graph layout algorithm in terms of computational performance and readability of the results. Thus, we perform a comparative evaluation of these transformations in terms of number of crossings, edge length, and impact on performance. We also provide two case studies showing how our transformations can be applied to real-life use cases.

We propose a new paradigm - called PK-clustering - to help social scientists create meaningful clusters in social networks. Many clustering algorithms exist but most social scientists find them difficult to understand, and tools do not provide any guidance to choose algorithms, or to evaluate results taking into account the prior knowledge of the scientists. Our work introduces a new clustering paradigm and a visual analytics user interface that address this issue. It is based on a process that 1) captures the prior knowledge of the scientists as a set of incomplete clusters, 2) runs multiple clustering algorithms (similarly to clustering ensemble methods), 3) visualizes the results of all the algorithms ranked and summarized by how well each algorithm matches the prior knowledge, 4) evaluates the consensus between user-selected algorithms and 5) allows users to review details and iteratively update the acquired knowledge. We describe our paradigm using an initial functional prototype, then provide two examples of use and early feedback from social scientists. We believe our clustering paradigm offers a novel constructive method to iteratively build knowledge while avoiding being overly influenced by the results of often-randomly selected black-box clustering algorithms.

            @article{pister:2005.02972,
            TITLE = {PK-clustering Integrating Prior Knowledge in Mixed Initiative Social Network Clustering},
            AUTHOR = {Alexis Pister, Paolo Buono, Jean-Daniel Fekete, Catherine Plaisant, Paola Valdivia},
            URL = {https://www.aviz.fr/pkclustering},
            JOURNAL = {IEEE Transactions on Visualization and Computer Graphics},
            PUBLISHER = {Institute of Electrical and Electronics Engineers},
            YEAR = {Accepted},
            KEYWORDS = {Social network analysis, network visualization, clustering, mixed initiative, prior knowledge, user interface},
            PDF = {https://arxiv.org/pdf/2005.02972.pdf}
          }
          

Automation in computing systems has always been considered a valuable solution to unburden the user. Internet of Things (IoT) technology best suits automation in different domains, such as home automation, retail, industry, and transportation, to name but a few. While these domains are strongly characterized by implicit user interaction, more recently, automation has been adopted also for the provision of interactive and immersive experiences that actively involve the users. IoT technology thus becomes the key for Smart Interactive Experiences (SIEs), i.e., immersive automated experiences created by orchestrating different devices to enable smart environments to fluidly react to the final users’ behavior. There are domains, e.g., cultural heritage, where these systems and the SIEs can support and provide several benefits. However, experts of such domains, while intrigued by the opportunity to induce SIEs, are facing tough challenges in their everyday work activities when they are required to automate and orchestrate IoT devices without the necessary coding skills. This paper presents a design approach that tries to overcome these difficulties thanks to the adoption of ontologies for defining Event-Condition-Action rules. More specifically, the approach enables domain experts to identify and specify properties of IoT devices through a user-defined semantics that, being closer to the domain experts’ background, facilitates them in automating the IoT devices behavior. We also present a study comparing three different interaction paradigms conceived to support the specification of user-defined semantics through a “transparent” use of ontologies. Based on the results of this study, we work out some lessons learned on how the proposed paradigms help domain experts express their semantics, which in turn facilitates the creation of interactive applications enabling SIEs.

            @article{Ardito2020,
              abstract = {Automation in computing systems has always been considered a valuable solution to unburden the user. Internet of Things (IoT) technology best suits automation in different domains, such as home automation, retail, industry, and transportation, to name but a few. While these domains are strongly characterized by implicit user interaction, more recently, automation has been adopted also for the provision of interactive and immersive experiences that actively involve the users. IoT technology thus becomes the key for Smart Interactive Experiences (SIEs), i.e., immersive automated experiences created by orchestrating different devices to enable smart environments to fluidly react to the final users' behavior. There are domains, e.g., cultural heritage, where these systems and the SIEs can support and provide several benefits. However, experts of such domains, while intrigued by the opportunity to induce SIEs, are facing tough challenges in their everyday work activities when they are required to automate and orchestrate IoT devices without the necessary coding skills. This paper presents a design approach that tries to overcome these difficulties thanks to the adoption of ontologies for defining Event-Condition-Action rules. More specifically, the approach enables domain experts to identify and specify properties of IoT devices through a user-defined semantics that, being closer to the domain experts' background, facilitates them in automating the IoT devices behavior. We also present a study comparing three different interaction paradigms conceived to support the specification of user-defined semantics through a “transparent” use of ontologies. Based on the results of this study, we work out some lessons learned on how the proposed paradigms help domain experts express their semantics, which in turn facilitates the creation of interactive applications enabling SIEs.},
              author = {Ardito, Carmelo and Desolda, Giuseppe and Lanzilotti, Rosa and Malizia, Alessio and Matera, Maristella and Buono, Paolo and Piccinno, Antonio},
              doi = {10.1007/s00779-020-01457-5},
              issn = {1617-4917},
              journal = {Personal and Ubiquitous Computing},
              title = {User-defined semantics for the design of IoT systems enabling smart interactive experiences},
              url = {https://doi.org/10.1007/s00779-020-01457-5},
              year = {2020}
              }              
          

Parallel Aggregated Ordered Hypergraph (PAOH) is a novel technique to visualize dynamic hypergraphs. Hypergraphs are a generalization of graphs where edges can connect several vertices. Hypergraphs can be used to model networks of business partners or co-authorship networks with multiple authors per article. A dynamic hypergraph evolves over discrete time slots. PAOH represents vertices as parallel horizontal bars and hyperedges as vertical lines, using dots to depict the connections to one or more vertices. We describe a prototype implementation of Parallel Aggregated Ordered Hypergraph, report on a usability study with 9 participants analyzing publication data, and summarize the improvements made. Two case studies and several examples are provided. We believe that PAOH is the first technique to provide a highly readable representation of dynamic hypergraphs. It is easy to learn and well suited for medium size dynamic hypergraphs (50-500 vertices) such as those commonly generated by digital humanities projects - our driving application domain.

            @article{valdivia:hal-02264960,
            TITLE = {Analyzing Dynamic Hypergraphs with Parallel Aggregated Ordered Hypergraph Visualization},
            AUTHOR = {Valdivia, Paola R and Buono, Paolo and Plaisant, Catherine and Dufournaud, Nicole and Fekete, Jean-Daniel},
            URL = {https://hal.inria.fr/hal-02264960},
            JOURNAL = {IEEE Transactions on Visualization and Computer Graphics},
            PUBLISHER = {Institute of Electrical and Electronics Engineers},
            YEAR = {2020},
            DOI = {10.1109/TVCG.2019.2933196},
            KEYWORDS = {interaction ; usability ; digital humanities ; case study ; dynamic hypergraph ; Index Terms-dynamic graph},
            PDF = {https://hal.inria.fr/hal-02264960/file/Paohvis.pdf},
            HAL_ID = {hal-02264960},
            HAL_VERSION = {v1},
          }
          

This paper reports the assessment of the infographics-value (IGV) short scale, designed to measure the value in the use of infographics. The scale was made to assess the implicit quality dimensions of infographics. These dimensions were experienced during the execution of tasks in a contextualized scenario. Users were asked to retrieve a piece of information by explicitly interacting with the infographics. After usage, they were asked to rate quality dimensions of infographics, namely, usefulness, intuitiveness, clarity, informativity, and beauty; the overall value perceived from interacting with infographics was also included in the survey. Each quality dimension was coded as a six-point rating scale item, with overall value included. The proposed IGV short scale model was validated with 650 people. Our analysis confirmed that all considered dimensions in our scale were independently significant and contributed to assessing the implicit value of infographics. The IGV short scale is a lightweight but exhaustive tool to rapidly assess the implicit value of an explicit interaction with infographics in daily tasks, where value in use is crucial to measuring the situated effectiveness of visual tools.

Daily experiences in working with various types of computer systems show that, despite the offered functionalities, users have many difficulties, which affect their overall User eXperience (UX). The UX focus is on aesthetics, emotions and social involvement, but usability has a great influence on UX. Usability evaluation is acknowledged as a fundamental activity of the entire development process in software practices. Research in Human-Computer Interaction has proposed methods and tools to support usability evaluation. However, when performing an evaluation study, novice evaluators still have difficulties to identify usability problems and to understand their causes: they would need easier to use and possibly automated tools. This article describes four visualization techniques whose aim is to support the work of evaluators when performing usability tests to evaluate websites. Specifically, they help detect �usability smells�, i.e. hints on web pages that might present usability problems, by visualizing the paths followed by the test participants when navigating in a website to perform a test task. A user study with 15 participants compared the four techniques and revealed that the proposed visualizations have the potential to be valuable tools for novice usability evaluators. These first results should push researchers towards the development of further tools that are capable to support the detection of other types of UX smells in the evaluation of computer systems and that can be translated into common industry practices.

            @ARTICLE{8939398,
              author={P. {Buono} and D. {Caivano} and M. F. {Costabile} and G. {Desolda} and R. {Lanzilotti}},
              journal={IEEE Access},
              title={Towards the Detection of UX Smells: The Support of Visualizations},
              year={2020},
              volume={8},
              number={},
              pages={6901-6914},
              keywords={User interfaces;website evaluation;design for quality;user eXperience;usability},
              doi={10.1109/ACCESS.2019.2961768},
              ISSN={2169-3536},
              month={}
            }
          

New Information and Communication Technologies have a large potential to improve general public awareness of the importance of Cultural Heritage (CH) and to provide tools that can make visits to historical sites more interesting and enjoyable. The Internet of Things (IoT) technology can further contribute to these goals, by allowing visitors to museum and CH sites to manipulate smart objects by receiving information that stimulates emotions, understanding and appropriation of the contents. In our research, interaction paradigms and innovative methods are developed to allow curators and guides of cultural sites (i.e., domain experts) to manage interactive IoT-based environments, in order to create Smart Interactive Experiences, which are usage situations created by synchronizing many available smart objects to specific situations that might better satisfy the needs of the visitors. This article illustrates a system that, by means of a tangible user interface, integrated by pattern recognition and computer vision techniques, supports CH experts in creating Smart Interactive Experiences by properly tailoring the behavior of the involved smart objects. An experimental evaluation of the used techniques has been performed and it is presented and discussed.

            @article{BALDUCCI2020142,
              title = "Improving smart interactive experiences in cultural heritage through pattern recognition techniques",
              journal = "Pattern Recognition Letters",
              volume = "131",
              pages = "142 - 149",
              year = "2020",
              issn = "0167-8655",
              doi = "https://doi.org/10.1016/j.patrec.2019.12.011",
              url = "http://www.sciencedirect.com/science/article/pii/S0167865519303745",
              author = "Fabrizio Balducci and Paolo Buono and Giuseppe Desolda and Donato Impedovo and Antonio Piccinno",
              keywords = "Internet of Things, Smart interactive experiences, Smart, objects, Deep learning, Convolutional neural network, CH fruition"
            }
          

Robotics in education is a promising new area: social robots have started to move into schools as part of educational/learning technologies, playing roles in educational settings that range from tutors, teaching assistants and learners, to learning companions and therapeutic assistants. This paper provides an overview of the main computational methods required to program a social robot and equip it with social intelligence. Some applications of social robots in the field of education are reported to show how the use of educational robots may innovate the learning process at different levels and in various contexts.

The analysis of air quality data may reveal the quality of life and can prevent dangers for the citizen health. Assuming that some chemical compounds in the air produce a bad smell, people may detect that something is going wrong acting as sensors that alerts potential risks. This work presents a visual analytics approach to support air quality experts in the analysis of data produced by electronic nose devices. The approach consists in setting workflows to manage and transform raw data offering clustering and visualization techniques to analyze such information. The analysis is supported by calendar, map and line graph visualization techniques also maneuvering the clustering attributes. The interactive map is used to show the position of monitoring stations in order to support making hypothesis related to the data source locations.

    
            @Article{Buono2019,
            author="Buono, Paolo
            and Balducci, Fabrizio",
            title="MonitorApp: a web tool to analyze and visualize pollution data detected by an electronic nose",
            journal="Multimedia Tools and Applications",
            year="2019",
            month="May",
            day="17",
            abstract="The analysis of air quality data may reveal the quality of life and can prevent dangers for the citizen health. Assuming that some chemical compounds in the air produce a bad smell, people may detect that something is going wrong acting as sensors that alerts potential risks. This work presents a visual analytics approach to support air quality experts in the analysis of data produced by electronic nose devices. The approach consists in setting workflows to manage and transform raw data offering clustering and visualization techniques to analyze such information. The analysis is supported by calendar, map and line graph visualization techniques also maneuvering the clustering attributes. The interactive map is used to show the position of monitoring stations in order to support making hypothesis related to the data source locations.",
            issn="1573-7721",
            doi="10.1007/s11042-019-7676-3",
            url="https://doi.org/10.1007/s11042-019-7676-3"
          }
          

Recent technologies are offering today many possibilities to end users, which ask for continuous support in a variety of situations. Internet of things (IoT) and the proliferation of smart devices are offering many opportunities that raise the need to standardize protocols for their interoperability and interaction languages for their management. This paper proposes EUDroid, a system composed of a mobile application and an IoT device used as a pill reminder to allows the patients to correctly take their prescribed drugs. A web server stores and manages the therapies that can be de?ned by the end users. The web server also manages the communication between the app and the device. In order to validate the management of the therapies, a formal language has been proposed. It describes the behavior of different components of the IoT device, such as LEDs or buzzers, and de?nes when, with which delay, and for how long time a given event will last, to manage technical concepts related to smart devices for supporting them in following therapies more accurately.

 @ARTICLE{
              iet:/content/journals/10.1049/iet-sen.2017.0347,
              author = {Paolo Buono},
              author = {Fabio Cassano},
              author = {Alessandra Legretto},
              author = {Antonio Piccinno},
              ISSN = {1751-8806},
              language = {English},
              title = {EUDroid: a formal language specifying the behavior of IoT devices},
              journal = {IET Software},
              year = {2018},
              month = {June},
              publisher ={Institution of Engineering and Technology},
              copyright = {� Institution of Engineering and Technology},
              url = {http://digital-library.theiet.org/content/journals/10.1049/iet-sen.2017.0347}
            }
          

The growing availability of smart objects is stimulating researchers to investigate the Internet of Things (IoT) phenomenon from different perspectives. The potential of this technology is evident in different domains. In Cultural Heritage (CH), it may enhance access to CH collections, in order to ensure a more engaging visit experience and to increase the appropriation of CH content by visitors. So far, research on IoT has primarily focused on technical features of smart objects (e.g., how to program sensors and actuators), while there are very few approaches trying to facilitate the adoption of such a technology by end users. This lack limits the social and practical benefits of IoT; it creates barriers in all those usage scenarios where people would like to define the behavior of smart objects but they might not have the required programming skills. This is becoming evident in CH sites, where different stakeholders would benefit from managing ecosystems of interoperable smart objects to create enhanced visit experiences. This article presents a visual composition paradigm that allows non-programmers to synchronize the behavior of smart objects, thus determining more engaging user experiences. It discusses how the paradigm suites the need of curators and guides of CH sites to define smart visit experiences through which visitors can acquire CH content by interacting with the surrounding environment and the smart objects included in it. A serious game designed with professional guides of CH sites is used as a case study to show the potential of the presented approach.

Large interactive displays are increasingly placed in public (or semipublic) locations, including museums, shops, various city settings, and offices. This article discusses the evolution of such displays by looking at their use and analyzing how they are changing the concept of human-computer interaction through new modalities. By surveying the literature on systems using these displays, relevant features were identified and used as classification dimensions. The analysis provided may inform the design and development of future installations. A discussion on research challenges concludes the article.

 @article{10.1145/2682623,
            author = {Ardito, Carmelo and Buono, Paolo and Costabile, Maria Francesca and Desolda, Giuseppe},
            title = {Interaction with Large Displays: A Survey},
            year = {2015},
            issue_date = {April 2015},
            publisher = {Association for Computing Machinery},
            address = {New York, NY, USA},
            volume = {47},
            number = {3},
            issn = {0360-0300},
            url = {https://doi.org/10.1145/2682623},
            doi = {10.1145/2682623},
            journal = {ACM Comput. Surv.},
            month = feb,
            articleno = {Article 46},
            numpages = {38},
            keywords = {Public installations, multitouch displays, touchless interaction}
            }
          

- abstract here -

When working in distributed teams, it is very important to be aware of the activities of all members, since it provides hints about when they might be available for collaboration. We propose a novel visualization technique that combines several representations to show the daily patterns of team members' activities. It uses a 24 h circular display to facilitate international collaboration across time zones. Current calendar information can be compared to the typical patterns and reveal likely availability. User studies evaluating the tool that implements the proposed technique are reported and discussed.

The efforts of addressing user experience (UX) in product development keep growing, as demonstrated by the proliferation of workshops and conferences bringing together academics and practitioners, who aim at creating interactive software able to satisfy their users. This special issue focuses on 'Interplay between User Experience Evaluation and Software Development', stating that the gap between human- computer interaction and software engineering with regard to usability has somewhat been narrowed. Unfortunately, our experience shows that software development organizations perform few usability engineering activities or none at all. Several authors acknowledge that, in order to understand the reasons of the limited impact of usability engineering and UX methods, and to try to modify this situation, it is fundamental to thoroughly analyze current software development practices, involving practitioners and possibly working from inside the companies. This article contributes to this research line by reporting an experimental study conducted with software companies. The study has confirmed that still too many companies either neglect usability and UX, or do not properly consider them. Interesting problems emerged. This article gives suggestions on how they may be properly addressed, since their solution is the starting point for reducing the gap between research and practice of usability and UX. It also provides further evidence on the value of the research method, called Cooperative Method Development, based on the collaboration of researchers and practitioners in carrying out empirical research; it has been used in a step of the performed study and has revealed to be instrumental for showing practitioners why to improve their development processes and how to do so.

Atmospheric emission inventories are useful tools to support informed decision making in air quality management. In the framework of Apulia Region emission inventory, a tool for the industrial atmospheric emission management called Territorial Emissions Cadastre (CET) was developed. CET is a Web-based system able to store all data related to the industrial plants and to perform spatial queries; its components are used for synchronizing, exporting and querying the underlined database. CET also enables access to information that is useful to support air quality monitoring experts in their decision-making process. An innovative feature of CET is CETGE. It allows the users to visualize the industrial plants and the associated emissions in Google Earth, which provides an effective tool to display the most relevant industrial emission sources on a Regional area view. CETGE can be used by the stakeholders to evaluate and present alternative solutions for areas characterized by high impact emission sources.

Emission inventories are useful tools in air quality management policies. In the framework of Apulia Region (South of Italy) inventory, the Territorial Emission Cadastre (CET) was developed. CET stores the huge amount of data concerning industrial plants. In order to easily interact with input data and analyze them, a graphical user interface that includes a GIS (Geographical Information System) component was integrated (CETGIS). This paper focuses on the development of CETGIS and analysis possibilities provided by GIS technology, which allow decision makers to monitor the state of air quality and to evaluate the targets to be achieved.

In our Age of exponential technological advance, recent developments are determining an evolution of end users from passive information consumers into information producers. Users are increasingly willing and, indeed, determined to shape the software they use to tailor it to their own needs. Based on a brief review of research activities we performed in the last decade, this paper analyzes some challenges that software designers face to comply with the new roles of end users in the software life cycle, and discusses how to provide end users with software environments that empower them to become co-designers of their own tools and products. The examples reported in the paper show why and how end users are involved in design activities in various application domains.

In spite of advances in technologies for working with data, analysts still spend an inordinate amount of time diagnosing data quality issues and manipulating data into a usable form. This process of 'data wrangling' often constitutes the most tedious and time-consuming aspect of analysis. Though data cleaning and integration arelongstanding issues in the database community, relatively little research has explored how interactive visualization can advance the state of the art. In this article, we review the challenges and opportunities associated with addressing data quality issues. We argue that analysts might more effectively wrangle data through new interactive systems that integrate data verification, transformation, and visualization. We identify a number of outstanding research questions, including how appropriate visual encodings can facilitate apprehension of missing data, discrepant values, and uncertainty; how interactive visualizations might facilitate data transform specification; and how recorded provenance and social interaction might enable wider reuse, verification, and modification of data transformations.

Interaction design of mobile systems is a complex activity because it requires to consider new usability and user experience aspects in order to exploit the peculiar characteristics of mobile devices, such as their pervasive and ubiquitous nature. This paper discusses issues about designing, developing and evaluating mobile systems. Italy has a rich cultural heritage and the focus here is on the design of systems that enable interactive exploration of historical sites, not only for enhancing the user experience but also for learning purposes. It is reported the experience of researchers of the Interaction, Visualization and Usability lab at the University of Bari, Italy, in designing a mobile learning system, called Explore!, that supports young students learning ancient history during a visit to archaeological parks. The evaluation of Explore! through systematic field studies shows that the adopted approach is able to transform the visit to archaeological parks into a more complete and culturally rich experience.

The use of computers in education has escalated rapidly during the last two decades. At the same time, technology advances have opened a new field of use, namely computer-based edutainment education in the form of entertainment where learners can achieve their learning goals while having fun. By meeting some of their psychological needs, computer games, if adequately designed, can motivate children to learn. Research on this approach has paved the way for the use of electronic games not only for pure entertainment but also as education tools.
The deployment of location-based multimedia services is continuously expanding from its early use in tourist guide systems and art installations to current, widespread applications such as vehicle navigation assistance and mobile gaming. Games on mobile phones, more than other interactive technologies, have become a significant part of the contemporary culture experienced by young people. Mobile games that associate real-world elements with the virtual objects on the phone, as occurs in augmented reality and context-aware systems, open up a wider game design space by exploiting multimedia and multimodal features of real-world elements. A representative example on how ubiquitous and mobile technologies can provide opportunities for novel learning experiences out of the classroom is discussed elsewhere.
The use of mobile games as learning tools is gaining increased support for several reasons: mobile devices are associated with low cost, accessibility, flexibility, and portability. Furthermore, mobile games are engaging, and inspire curiosity and increased motivation. In addition, mobile games as educational media are supported by pedagogical theories, including constructivism, in which learners actively construct their own knowledge instead of passively receiving information from a teacher or guide, and situated cognition, in which students draw on real-world situations and become immersed in particular circumstances. Empirical studies have shown evidence that educational electronic games promote effective learning, primarily of mathematics, science, physics, music, game accessibility guidelines, and history.
M-learning games, such as the one presented in the main article, imbue young students with a better understanding of history, helping players to acquire deeper knowledge while playing in an archaeological park. The gameplay method offers several benefits. Firstly, play is fun and amusing. Because it's enjoyably, players are less likely to forget learned facts and skills; hence, this property of the gameplay method brings obvious pedagogical benefits. A second positive aspect of play is that different skills can be practiced simultaneously. In a group-based game like Explore!, each player contributes with her or his most congenial skills. Finally, play is a relational activity, stimulating collaboration and encouraging interaction within and among groups.