EDBT 2026 Demo / reviewers in the wild / expert
João Guerreiro 0002
dblp:42/8124-2 · also João Pedro Vieira Guerreiro
· DBLP profile ↗
35ranked-venue papers
11as first author
15since 2021 · last 2025
0000-0002-0952-8368ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Human-computer interaction and ubiquitous computing · 33 · 10 first-author · 13 since 2021Graphics, computer vision, multimedia, augmented reality and games · 3 · 1 first-author · 3 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2025 | Designing and Evaluating a VR Boxing Experience with Blind People
Diogo Furtado, Renato Alexandre Ribeiro, Manuel Piçarra, Letícia Seixas Pereira, Carlos Duarte, André Rodrigues 0002, João Guerreiro 0002 |
CHI | 7 |
| 2025 | Perspectives on Mixed-Ability Competition
Pedro Trindade, João Guerreiro 0002, André Rodrigues 0002 |
CHI | 2 |
| 2025 | Exploring Aiming Techniques for Blind People in Virtual RealityabstractAiming tasks are common in VR, but are challenging to perform without vision. They require identifying a target's location and then precisely aiming and selecting it. In this paper, we explore how to support blind people in aiming tasks using a VR Archery scenario. We implemented three techniques: 1) Spatialized Audio, a baseline where the target emits a specific 3D sound to convey its location; 2) Target Confirmation, where the previous condition is augmented with secondary Beep sounds to indicate proximity to the target; and 3) Reticle-Target perspective, where the auditory feedback conveys the relation between the target and the user's aiming reticle. A study with 15 blind participants compared the three techniques under two scenarios: stationary and moving targets. Target Confirmation and Reticle-Target Perspective clearly outperformed Spatialized Audio, but user preferences were evenly split between these two techniques. We discuss how our findings may support the development of VR experiences that are more accessible and enjoyable to a broader range of users. Manuel Piçarra, Inês Gonçalves, André Rodrigues 0002, João Guerreiro 0002 |
IEEE Trans. Vis. Comput. Graph. | 5 |
| 2024 | Speed-of-Light VR for Blind People: Conveying the Location of Arm-Reach TargetsabstractInteracting with close-range objects in Virtual Reality (VR) is often prompted by visual cues, making it hard for visually impaired people to perceive their location and interact with them. To study how to enable blind users to locate and interact with close virtual objects, we adapted the arcade Speed-of-Light game as a blind-accessible VR application. We implemented three techniques: 1) Speech Feedback (e.g., “Top Right”), 2) Sonification, and 3) 2D Grid Position (e.g., “A3” for column and row); and conducted a user study with 15 blind participants aiming to provide insights into the design of non-visual techniques that convey information about targets at arm-reach. Speech Feedback was the most intuitive overall but verbose and the least flexible, while 2D Grid Position was found straightforward for regular spreadsheet users. Results also showed greater difficulty with Sonification, although it was valued by few participants who appreciated the challenge. Diogo Lança, Manuel Piçarra, Inês Gonçalves, Uran Oh, André Rodrigues 0002, João Guerreiro 0002 |
ASSETS | 6 |
| 2024 | The Trick is to Stay Behind?: Defining and Exploring the Design Space of Player Balancing MechanicsabstractIn multiplayer gaming, skill disparity can lead to frustrating and excluding experiences. Balancing approaches exist to level the playing field (e.g., providing aim assistance to low-performing players), but it is unclear how different design choices affect individual player experience. We first introduce a design space for balancing mechanics encompassing six categories: Determination, Timing, Targeting, Effect, Feedback, and Information. We then present a mixed-methods study, focused on the effect of two subcategories: Targeting Direction and Effect Dependency on skill. In this study, eight pairs of participants played a game prototype and experienced seven balancing mechanics. We collected data from questionnaires and group interviews, revealing implications for future designs, including the importance of 1) merited victory that does not ignore individual achievements, 2) sense of agency when determining the balancing before and during gameplay, and 3) balancing as an intrinsic part of the game that does not disrupt the core gameplay. David Gonçalves, Pedro Pais, João Guerreiro 0002, Tiago João Vieira Guerreiro, André Rodrigues 0002 |
CHI | 4 |
| 2024 | A Living Framework for Understanding Cooperative GamesabstractPlaying cooperative games is recognised as a positive social activity. Yet, we have limited means to rigorously define or communicate the structures that govern these experiences, hindering attempts at consolidating knowledge and limiting the potential of design efforts. In this work, we introduce the Living Framework for Cooperative Games (LFCG), a framework derived from a multi-step systematic analysis of 129 cooperative games with contributions of eleven researchers. We describe how LFCG can be used as a tool for analyses and ideation, and as a shared language for describing a game’s design. LFCG is published as a web application to facilitate use and appropriation. It supports the creation, dissemination and aggregation of game reports and specifications; and enables stakeholders to extend and publish custom versions. Lastly, we discuss using a research-driven approach for formalising game structures and the advantages of community contributions for consolidation and reach. Pedro Pais, David Gonçalves, Daniel Reis, João Cadete Nunes Godinho, João Filipe Morais, Manuel Piçarra, Pedro Trindade, Dmitry Alexandrovsky, Kathrin Maria Gerling, João Guerreiro 0002, André Rodrigues 0002 |
CHI | 10 |
| 2024 | Investigating Virtual Reality Locomotion Techniques with Blind PeopleabstractMany Virtual Reality (VR) locomotion techniques have been proposed, but those explored for and with blind people are often custom-made or require specialized equipment. Consequently, it is unclear how popular techniques can support blind people’s VR locomotion, blocking access to most VR experiences. We implemented three popular techniques — Arm Swinging, Linear Movement (joystick-based steering), and Point & Teleport — with minor adaptations for accessibility. We conducted a study with 14 blind participants consisting of navigation tasks with these techniques and a semi-structured interview. We found no differences in overall performance (e.g., completion time), but contrasting preferences. Findings highlight the challenges and advantages of each technique and participants’ strategies. We discuss, among others, how augmenting the techniques enabled blind people to navigate in VR, the greater control of movement of Arm Swinging, the simplicity and familiarity of Linear Movement, and the potential for efficiency and for scanning the environment of Point & Teleport. Renato Alexandre Ribeiro, Inês Gonçalves, Manuel Piçarra, Letícia Seixas Pereira, Carlos Duarte, André Rodrigues 0002, João Guerreiro 0002 |
CHI | 7 |
| 2024 | Crafting Virtual Realities: Designing a VR End-User Authoring Platform for Personalised Exposure TherapyabstractAbstract Exposure therapy (ET) gradually introduces people to the objects, animals, or situations they fear to help them overcome the angst with that source of anxiety. VR(ET) enables exposure to various triggers in the safety of the clinical or home environments. While prior work has explored how specific VR environments support therapy in contexts such as social anxiety or arachnophobia, therapy’s individualised nature is often overlooked. We used an iterative participatory design approach to develop an authoring platform for therapists, enabling them to tailor VR environments during exposure by changing and parameterising elements and reapplying past scenes. We used this platform as a design probe in a study with ten therapists to elicit discussions about the design of VRET experiences and therapists’ authoring needs. Findings highlight the value of controlling the stimuli presented to patients and deviating from stereotypical scenarios, and the importance of further investigating the therapist’s virtual representation. João P. Ferreira, Filipa Ferreira-Brito, João Guerreiro 0002, Tiago João Vieira Guerreiro |
ISMAR | 3 |
| 2023 | TACTOPI: Exploring Play with an Inclusive Multisensory Environment for Children with Mixed-Visual AbilitiesabstractPlayful robotics engages children in learning through play experiences while simultaneously developing critical thinking, and social, cognitive, and motor skills through play. Such playful experiences are particularly valuable in inclusive education to promote social and inclusive behaviors. We present TACTOPI, an inclusive and playful multisensory environment that leverages tangible interaction and a robot as the main character. We investigate how TACTOPI supports play in 10 dyads of children with mixed visual abilities. Results show that multisensory elements supported children to experience activities as joyful. Storytelling and guided-play added a layer of meaningfulness to the activities, and the robot engaged children in minds-on thinking. TACTOPI afforded children to engage in collaborative social play and facilitated supportive and inclusive behaviours. We contribute with a playful multisensory environment, an analysis of the effect of its components on social, cognitive, and inclusive play, and design considerations for inclusive multisensory environments that prioritize play. Ana Cristina Pires 0001, Lúcia Verónica Abreu, Filipa Rocha, Hugo Simão, João Guerreiro 0002, Hugo Nicolau, Tiago João Vieira Guerreiro |
IDC | 5 |
| 2023 | "My Zelda Cane": Strategies Used by Blind Players to Play Visual-Centric Digital GamesabstractMainstream games are typically designed around the visual experience, with behaviors and interactions highly dependent on vision. Despite this, blind people are playing mainstream games while dealing with and overcoming inaccessible content, often together with friends and audiences. In this work, we analyze over 70 hours of YouTube videos, where blind content-creators play visual-centric games. We point out the various strategies employed by players to overcome barriers that permeate mainstream games. We reflect on ways to enable and improve blind players’ experience with these games, shedding light on the positive and negative consequences of apparently benign design choices. Our observations underline how game elements are appropriated for accessibility, the incidental consequences of audio design, and the trade-offs between accessibility, agency, and engagement. David Gonçalves, Manuel Piçarra, Pedro Pais, João Guerreiro 0002, André Rodrigues 0002 |
CHI | 4 |
| 2023 | Coding Together: On Co-located and Remote Collaboration between Children with Mixed-Visual AbilitiesabstractCollaborative coding environments foster learning, social skills, computational thinking training, and supportive relationships. In the context of inclusive education, these environments have the potential to promote inclusive learning activities for children with mixed-visual abilities. However, there is limited research focusing on remote collaborative environments, despite the opportunity to design new modes of access and control of content to promote more equitable learning experiences. We investigated the tradeoffs between remote and co-located collaboration through a tangible coding kit. We asked ten pairs of mixed-visual ability children to collaborate in an interdependent and asymmetric coding game. We contribute insights on six dimensions - effectiveness, computational thinking, accessibility, communication, cooperation, and engagement - and reflect on differences, challenges, and advantages between collaborative settings related to communication, workspace awareness, and computational thinking training. Lastly, we discuss design opportunities of tangibles, audio, roles, and tasks to create inclusive learning activities in remote and co-located settings. Filipa Rocha, Filipa Correia, Isabel Neto, Ana Cristina Pires 0001, João Guerreiro 0002, Tiago João Vieira Guerreiro, Hugo Nicolau |
CHI | 5 |
| 2023 | The Design Space of the Auditory Representation of Objects and Their Behaviours in Virtual Reality for Blind PeopleabstractAs virtual reality (VR) is typically designed in terms of visual experience, it poses major challenges for blind people to understand and interact with the environment. To address this, we propose a design space to explore how to augment objects and their behaviours in VR with a nonvisual audio representation. It intends to support designers in creating accessible experiences by explicitly considering alternative representations to visual feedback. To demonstrate its potential, we recruited 16 blind users and explored the design space under two scenarios in the context of boxing: understanding the location of objects (the opponent's defensive stance) and their movement (opponent's punches). We found that the design space enables the exploration of multiple engaging approaches for the auditory representation of virtual objects. Our findings depicted shared preferences but no one-size-fits-all solution, suggesting the need to understand the consequences of each design choice and their impact on the individual user experience. João Guerreiro 0002, Seung A. Chung, André Rodrigues 0002, Uran Oh |
IEEE Trans. Vis. Comput. Graph. | 1 |
| 2022 | Authoring accessible media content on social networksabstractUser-generated content plays a key role in social networking, allowing a more active participation, socialisation, and collaboration among users. In particular, media content has been gaining a lot of ground, allowing users to express themselves through different types of formats such as images, GIFs and videos. The majority of this growing type of online visual content remains inaccessible to a part of the population, in particular for those who have a visual disability, despite available tools to mitigate this source of exclusion. We sought to understand how people are perceiving this type of online content in their networks and how support tools are being used. To do so, we conducted a user study, with 258 social network users through an online questionnaire, followed by interviews with 20 of them – 7 blind users and 13 sighted users. Results show how the different approaches being employed by major platforms may not be sufficient to address this issue properly. Our findings reveal that users are not always aware of the possibility and the benefits of adopting accessible practices. From the general perspectives of end-users experiencing accessible practices, concerning barriers encountered, and motivational factors, we also discuss further approaches to create more user engagement and awareness. Letícia Seixas Pereira, José Coelho 0002, André Rodrigues 0002, João Guerreiro 0002, Tiago João Vieira Guerreiro, Carlos Duarte |
ASSETS | 4 |
| 2022 | Virtual Reality for Health and WellbeingabstractVirtual Reality (VR) has become a mainstream opportunity to develop immersive environments where people are exposed to relevant stimuli in a systematic but safe way. Besides the controlled exposure to stimuli, VR systems enable a more efficient and unbiased gathering of information with practical applications in diagnosis, intervention, and health monitoring processes. Nonetheless, scientific literature has demonstrated that interacting with VR technology and its peripherals can be challenging, especially in populations less familiar with technology (e.g., older adults) or with clinical conditions that are not adequately accommodated by the technology, such as cognitive (e.g., dementia) or physical impairments (e.g., blindness). This workshop will focus on systems, technological approaches, and theoretical frameworks to develop user/patient-centred VR tools for diagnosis, intervention, and monitoring of health and wellbeing outcomes. Moreover, we welcome work focused on accessibility issues, aiming to promote equal access and opportunity to use VR tools by people with diverse abilities. Filipa Ferreira-Brito, Hristijan Gjoreski, Oscar Mayora-Ibarra, Mitja Lustrek, Emilija Kizhevska, João Guerreiro 0002, Kathrin Maria Gerling, Sergi Bermúdez i Badia, Tiago João Vieira Guerreiro |
MUM | 6 |
| 2022 | From skeuomorphism to flat design: age-related differences in performance and aesthetic perceptionsabstractThe design of graphical user interfaces has been evolving from skeuomorph interfaces – which use elements that mimic the aesthetics and functionality of their real-world counterparts – to minimalist and flat designs. Despite the growing popularity of these new design approaches, they can be challenging for older adults who experience a decline in visual and cognitive abilities. Still, little is known about user performance, aesthetic perception, and preference of older adults, particularly in comparison to younger users and traditional skeuomorph interfaces. In this paper, we examine the performance and aesthetic perception of older (65–77 years old) and younger (20–40) adults with three design approaches: skeuomorph, skeuominimalist, and flat design. Results show flat design is either slower or less accurate than traditional skeuomorph interfaces for older adults across three tasks: visual search, identifying clickable objects, and multiple page navigation. Younger adults were less susceptible to performance differences between design approaches, but still subject to ‘click uncertainty’ with flat interfaces. Skeuominimalism did not show clear performance benefits over flat design or skeuomorphism, while the latter reduced the performance gap between age groups. Finally, younger adults preferred the simplicity of skeuominimalism, while older adults preferred skeuomorph interfaces because of the perceived usability, beauty, and trustiness. Inês Cunha Vaz Pereira Urbano, João Guerreiro 0002, Hugo Nicolau |
Behav. Inf. Technol. | 2 |
| 2020 | Investigating the Opportunities for Technologies to Enhance QoL with Stroke Survivors and their FamiliesabstractThere are over 80 million stroke survivors globally, making it the main cause of long-term disability worldwide. Not only do the challenges associated with stroke affect the quality of life (QoL) of survivors, but also of their families. To explore these challenges and define design opportunities for technologies to improve the QoL of both stakeholders, we conducted semi-structured interviews with 10 survivors and one of their family members. We uncovered three major interlinked themes: strategies to cope with technological barriers, the (in)adequacy of assistive technologies, and limitations of the rehabilitation process. Findings highlight multiple design opportunities, including the need for meaningful patient-centered tools and methods to improve rehabilitation effectiveness, emotion-aware computing for family emotional support, and re-thinking the nature of assistive technologies to consider the perception of transitory stroke-related disabilities. We thus argue for a new class of dual-purpose technologies that fit survivors' abilities while promoting the regain of function. Inês Santos Silva, João Guerreiro 0002, Marlene Cristina Neves Rosa, Joana Campos 0001, Augusto Gil Pascoal, Sofia Pinto, Hugo Nicolau |
CHI | 2 |
| 2020 | Open Challenges of Blind People Using SmartphonesabstractBlind people face significant challenges when using smartphones. The focus on improving nonvisual mobile accessibility has been at the level of touchscreen access. Our research investigates the challenges faced by blind people in their everyday usage of mobile phones. In this article, we present a set of studies performed with the target population, novices and experts, using a variety of methods, targeted at identifying and verifying challenges; and coping mechanisms. Through a multiple methods approach we identify and validate challenges locally with a diverse set of user expertise and devices, and at scale through the analyses of the largest Android and iOS dedicate forums for blind people. We contribute with a prioritized corpus of smartphone challenges for blind people, and a discussion on a set of directions for future research, which tackle the open and often overlooked challenges. André Rodrigues 0002, Hugo Nicolau, Kyle Montague, João Guerreiro 0002, Tiago João Vieira Guerreiro |
Int. J. Hum. Comput. Interact. | 4 |
| 2020 | Virtual navigation for blind people: Transferring route knowledge to the real-World
João Guerreiro 0002, Daisuke Sato 0001, Dragan Ahmetovic, Eshed Ohn-Bar, Kris Makoto Kitani, Chieko Asakawa |
Int. J. Hum. Comput. Stud. | 1 |
| 2020 | Collaborative Tabletops for Blind People: The Effect of Auditory Design on Workspace AwarenessabstractInteractive tabletops offer unique collaborative features, particularly their size, geometry, orientation and, more importantly, the ability to support multi-user interaction. Although previous efforts were made to make interactive tabletops accessible to blind people, the potential to use them in collaborative activities remains unexplored. In this paper, we present the design and implementation of a multi-user auditory display for interactive tabletops, supporting three feedback modes that vary on how much information about the partners' actions is conveyed. We conducted a user study with ten blind people to assess the effect of feedback modes on workspace awareness and task performance. Furthermore, we analyze the type of awareness information exchanged and the emergent collaboration strategies. Finally, we provide implications for the design of future tabletop collaborative tools for blind users. Daniel Mendes, Sofia Reis, João Guerreiro 0002, Hugo Nicolau |
Proc. ACM Hum. Comput. Interact. | 3 |
| 2019 | CaBot: Designing and Evaluating an Autonomous Navigation Robot for Blind PeopleabstractNavigation robots have the potential to overcome some of the limitations of traditional navigation aids for blind people, specially in unfamiliar environments. In this paper, we present the design of CaBot (Carry-on roBot), an autonomous suitcase-shaped navigation robot that is able to guide blind users to a destination while avoiding obstacles on their path. We conducted a user study where ten blind users evaluated specific functionalities of CaBot, such as a vibro-tactile handle to convey directional feedback; experimented to find their comfortable walking speed; and performed navigation tasks to provide feedback about their overall experience. We found that CaBot's performance highly exceeded users' expectations, who often compared it to navigating with a guide dog or sighted guide. Users' high confidence, sense of safety, and trust on CaBot poses autonomous navigation robots as a promising solution to increase the mobility and independence of blind people, in particular in unfamiliar environments. João Guerreiro 0002, Daisuke Sato 0001, Saki Asakawa, Huixu Dong, Kris Makoto Kitani, Chieko Asakawa |
ASSETS | 1 |
| 2019 | The Design Space of Nonvisual Word CompletionabstractWord completion interfaces are ubiquitously available in mobile virtual keyboards; however, there is no prior research on how to design these interfaces for screen reader users. In addressing this, we propose a design space for nonvisual representation of word completions. The design space covers seven categories aiming to identify challenges and opportunities for interaction design in an unexplored research topic. It is intended to guide the design of novel interaction techniques, serving as a framework for researchers and practitioners working on nonvisual word completion. To demonstrate its potential, we engaged blind users in an exploration of the design space, to create their own bespoke word completion solutions. Through this study we found that users create alternative interfaces that extended current screen readers' capabilities. Resulting interfaces are less conservative than mainstream solutions on notification frequency and cardinality. Customization decisions were based on perceived benefits/costs and varied depending on multiple factors such as users' perceived prediction accuracy, potential keystroke gains, and situational restrictions. Hugo Nicolau, André Rodrigues 0002, André R. B. Santos, Tiago João Vieira Guerreiro, Kyle Montague, João Guerreiro 0002 |
ASSETS | 6 |
| 2019 | Airport Accessibility and Navigation Assistance for People with Visual ImpairmentsabstractPeople with visual impairments often have to rely on the assistance of sighted guides in airports, which prevents them from having an independent travel experience. In order to learn about their perspectives on current airport accessibility, we conducted two focus groups that discussed their needs and experiences in-depth, as well as the potential role of assistive technologies. We found that independent navigation is a main challenge and severely impacts their overall experience. As a result, we equipped an airport with a Bluetooth Low Energy (BLE) beacon-based navigation system and performed a real-world study where users navigated routes relevant for their travel experience. We found that despite the challenging environment participants were able to complete their itinerary independently, presenting none to few navigation errors and reasonable timings. This study presents the first systematic evaluation posing BLE technology as a strong approach to increase the independence of visually impaired people in airports. João Guerreiro 0002, Dragan Ahmetovic, Daisuke Sato 0001, Kris Makoto Kitani, Chieko Asakawa |
CHI | 1 |
| 2019 | BBeep: A Sonic Collision Avoidance System for Blind Travellers and Nearby PedestriansabstractWe present an assistive suitcase system, BBeep, for supporting blind people when walking through crowded environments. BBeep uses pre-emptive sound notifications to help clear a path by alerting both the user and nearby pedestrians about the potential risk of collision. BBeep triggers notifications by tracking pedestrians, predicting their future position in real-time, and provides sound notifications only when it anticipates a future collision. We investigate how different types and timings of sound affect nearby pedestrian behavior. In our experiments, we found that sound emission timing has a significant impact on nearby pedestrian trajectories when compared to different sound types. Based on these findings, we performed a real-world user study at an international airport, where blind participants navigated with the suitcase in crowded areas. We observed that the proposed system significantly reduces the number of imminent collisions. Seita Kayukawa, Keita Higuchi, João Guerreiro 0002, Shigeo Morishima, Yoichi Sato 0001, Kris Makoto Kitani, Chieko Asakawa |
CHI | 3 |
| 2018 | The Present and Future of Museum Accessibility for People with Visual ImpairmentsabstractPeople with visual impairments (PVI) have shown interest in visiting museums and enjoying visual art. Based on this knowledge, some museums provide tactile reproductions of artworks, specialized tours for PVI, or enable them to schedule accessible visits. However, the ability of PVI to visit museums is still dependent on the assistance they get from their family and friends or from the museum personnel. In this paper, we surveyed 19 PVI to understand their opinions and expectations about visiting museums independently, as well as the requirements of user interfaces to support it. Moreover, we increase the knowledge about the previous experiences, motivations and accessibility issues of PVI in museums. Saki Asakawa, João Guerreiro 0002, Dragan Ahmetovic, Kris Makoto Kitani, Chieko Asakawa |
ASSETS | 2 |
| 2018 | Modeling Expertise in Assistive Navigation Interfaces for Blind PeopleabstractEvaluating the impact of expertise and route knowledge on task performance can guide the design of intelligent and adaptive navigation interfaces. Expertise has been relatively unexplored in the context of assistive indoor navigation interfaces for blind people. To quantify the complex relationship between the user»s walking patterns, route learning, and adaptation to the interface, we conducted a study with 8 blind participants. The participants repeated a set of navigation tasks while using a smartphone-based turn-by-turn navigation guidance app. The results demonstrate the gradual evolution of user skill and knowledge throughout the route repetitions, significantly impacting the task completion time. In addition to the exploratory analysis, we take a step towards tailoring the navigation interface to the user»s needs by proposing a personalized recurrent neural network-based behavior model for expertise level classification. Eshed Ohn-Bar, João Guerreiro 0002, Dragan Ahmetovic, Kris Makoto Kitani, Chieko Asakawa |
IUI | 2 |
| 2017 | In-context Q&A to Support Blind People Using SmartphonesabstractBlind people face many barriers using smartphones. Still, previous research has been mostly restricted to non-visual gestural interaction, paying little attention to the deeper daily challenges of blind users. To bridge this gap, we conducted a series of workshops with 42 blind participants, uncovering application challenges across all levels of expertise, most of which could only be surpassed through a support network. We propose Hint Me!, a human-powered service that allows blind users to get in-app assistance by posing questions or browsing previously answered questions on a shared knowledge-base. We evaluated the perceived usefulness and acceptance of this approach with six blind people. Participants valued the ability to learn independently and anticipated a series of usages: labeling, layout and feature descriptions, bug workarounds, and learning to accomplish tasks. Creating or browsing questions depends on aspects like privacy, knowledge of respondents and response time, revealing the benefits of a hybrid approach. André Rodrigues 0002, Kyle Montague, Hugo Nicolau, João Guerreiro 0002, Tiago João Vieira Guerreiro |
ASSETS | 4 |
| 2017 | Virtual Navigation for Blind People: Building Sequential Representations of the Real-WorldabstractWhen preparing to visit new locations, sighted people often look at maps to build an a priori mental representation of the environment as a sequence of step-by-step actions and points of interest (POIs), e.g., turn right after the coffee shop. Based on this observation, we would like to understand if building the same type of sequential representation, prior to navigating in a new location, is helpful for people with visual impairments (VI). In particular, our goal is to understand how the simultaneous interplay between turn-by-turn navigation instructions and the relevant POIs in the route can aid the creation of a memorable sequential representation of the world. To this end, we present two smartphone-based virtual navigation interfaces: VirtualLeap, which allows the user to jump through a sequence of street intersection labels, turn-by-turn instructions and POIs along the route; and VirtualWalk, which simulates variable speed step-by-step walking using audio effects, whilst conveying similar route information. In a user study with 14 VI participants, most were able to create and maintain an accurate mental representation of both the sequential structure of the route and the approximate locations of the POIs. While both virtual navigation modalities resulted in similar spatial understanding, results suggests that each method is useful in different interaction contexts. João Guerreiro 0002, Dragan Ahmetovic, Kris Makoto Kitani, Chieko Asakawa |
ASSETS | 1 |
| 2015 | Faster Text-to-Speeches: Enhancing Blind People's Information Scanning with Faster Concurrent SpeechabstractBlind people rely mostly on the auditory feedback of screen readers to consume digital information. Still, how fast can information be processed remains a major problem. The use of faster speech rates is one of the main techniques to speed-up the consumption of digital information. Moreover, recent experiments have suggested the use of concurrent speech as a valid alternative when scanning for relevant information. In this paper, we present an experiment with 30 visually impaired participants, where we compare the use of faster speech rates against the use of concurrent speech. Moreover, we combine these two approaches by gradually increasing the speech rate with one, two and three voices. Results show that concurrent voices with speech rates slightly faster than the default rate, enable a significantly faster scanning for relevant content, while maintaining its comprehension. In contrast, to keep-up with concurrent speech timings, One-Voice requires larger speech rate increments, which cause a considerable loss in performance. Overall, results suggest that the best compromise between efficiency and the ability to understand each sentence is the use of Two-Voices with a rate of 1.75*default-rate (approximately 278 WPM). João Guerreiro 0002, Daniel Gonçalves 0002 |
ASSETS | 1 |
| 2015 | TabLETS Get Physical: Non-Visual Text Entry on Tablet DevicesabstractTablet devices can display full-size QWERTY keyboards similar to the physical ones. Yet, the lack of tactile feedback and the inability to rest the fingers on the home keys result in a highly demanding and slow exploration task for blind users. We present SpatialTouch, an input system that leverages previous experience with physical QWERTY keyboards, by supporting two-handed interaction through multitouch exploration and spatial, simultaneous audio feedback. We conducted a user study, with 30 novice touchscreen participants entering text under one of two conditions: (1) SpatialTouch or (2) mainstream accessibility method Explore by Touch. We show that SpatialTouch enables blind users to leverage previous experience as they do a better use of home keys and perform more efficient exploration paths. Results suggest that although SpatialTouch did not result in faster input rates overall, it was indeed able to leverage previous QWERTY experience in contrast to Explore by Touch. João Guerreiro 0002, André Rodrigues 0002, Kyle Montague, Tiago João Vieira Guerreiro, Hugo Nicolau, Daniel Gonçalves 0002 |
CHI | 1 |
| 2014 | Text-to-speeches: evaluating the perception of concurrent speech by blind peopleabstractOver the years, screen readers have been an essential tool for assisting blind users in accessing digital information. Yet, its sequential nature undermines blind people's ability to efficiently find relevant information, despite the browsing strategies they have developed. We propose taking advantage of the Cocktail Party Effect, which states that people are able to focus on a single speech source among several conversations, but still identify relevant content in the background. Therefore, oppositely to one sequential speech channel, we hypothesize that blind people can leverage concurrent speech channels to quickly get the gist of digital information. In this paper, we present an experiment with 23 participants, which aims to understand blind people's ability to search for relevant content listening to two, three or four concurrent speech channels. Our results suggest that it is easy to identify the relevant source with two and three concurrent talkers. Moreover, both two and three sources may be used to understand the relevant source content depending on the task intelligibility demands and user characteristics. João Guerreiro 0002, Daniel Gonçalves 0002 |
ASSETS | 1 |
| 2014 | B#: chord-based correction for multitouch braille inputabstractBraille has paved its way into mobile touchscreen devices, providing faster text input for blind people. This advantage comes at the cost of accuracy, as chord typing over a flat surface has proven to be highly error prone. A misplaced finger on the screen translates into a different or unrecognized character. However, the chord itself gathers information that can be leveraged to improve input performance. We present B#, a novel correction system for multitouch Braille input that uses chords as the atomic unit of information rather than characters. Experimental results on data collected from 11 blind people revealed that B# is effective in correcting errors at character-level, thus providing opportunities for instant corrections of unrecognized chords; and at word-level, where it outperforms a popular spellchecker by providing correct suggestions for 72% of incorrect words (against 38%). We finish with implications for designing chord-based correction system and avenues for future work. Hugo Nicolau, Kyle Montague, Tiago João Vieira Guerreiro, João Guerreiro 0002, Vicki L. Hanson |
CHI | 4 |
| 2013 | The today and tomorrow of Braille learningabstractDespite the overwhelming emergence of accessible digital technologies, Braille still plays a role in providing blind people with access to content. Nevertheless, many fail to see the benefits of nurturing Braille, particularly given the time and effort required to achieve proficiency. Our research focuses on maximizing access and motivation to learn and use Braille. We present initial insights from 5 interviews with blind people, comprising of Braille instructors and students, where we characterize the learning process and usage of Braille. Based on our findings, we have identified a set of opportunities around Braille education. Moreover, we devised scenarios, and built hardware and software solutions to motivate discovery and retention of Braille literacy. João Guerreiro 0002, Daniel Gonçalves 0002, Diogo Marques 0001, Tiago João Vieira Guerreiro, Hugo Nicolau, Kyle Montague |
ASSETS | 1 |
| 2013 | UbiBraille: designing and evaluating a vibrotactile Braille-reading deviceabstractBlind people typically resort to audio feedback to access information on electronic devices. However, this modality is not always an appropriate form of output. Novel approaches that allow for private and inconspicuous interaction are paramount. In this paper, we present a vibrotactile reading device that leverages the users' Braille knowledge to read textual information. UbiBraille consists of six vibrotactile actuators that are used to code a Braille cell and communicate single characters. The device is able to simultaneously actuate the users' index, middle, and ring fingers of both hands, providing fast and mnemonic output. We conducted two user studies on UbiBraille to assess both character and word reading performance. Character recognition rates ranged from 54% to 100% and were highly character- and user-dependent. Indeed, participants with greater expertise in Braille reading/writing were able to take advantage of this knowledge and achieve higher accuracy rates. Regarding word reading performance, we investigated four different vibrotactile timing conditions. Participants were able to read entire words and obtained recognition rates up to 93% with the most proficient ones being able achieve a rate of 1 character per second. Hugo Nicolau, João Guerreiro 0002, Tiago João Vieira Guerreiro, Luís Carriço |
ASSETS | 2 |
| 2012 | Visualiz'em: "show me more about him!"abstractOur Personal Information is now scattered among several applications and personal devices in an unrelated, but still connected, information network. We have never had so much information at our disposal as we have now, giving us the opportunities to find information about other people, a very frequent need. While previous works have proposed several solutions to relate data from multiple sources that does not happen at the presentation level. When needing information about people, we still have to navigate among sources to find it. Besides troublesome, it is difficult to have an overall characterization of what each person represents to us. We argue that gathering information from all these sources and presenting it in a unified interface benefits the user by providing a quick and meaningful overview of who that person is and how he/she is related to him/her. We present Visualiz'em, a personal visualization tool based on three interconnected views: Profile, Tagcloud and Timeline. When compared to traditional applications Visualiz'em provides a faster and richer overview of whom a person is and his/her relationship with the user. Moreover, results show that our visualization tool promotes serendipitous behaviors, allowing users to easily explore data and find interaction patterns. João Guerreiro 0002, Daniel Gonçalves 0002 |
AVI | 1 |
| 2010 | Surpassing farley files: opportunities and challenges on obtaining personally relevant informationabstractThe proliferation of personal devices and their constant awareness of our interactions have generated an enormous amount of data that can be useful to help the user obtaining relevant information when needed. Our approach uses the personal information on users' devices, together with public online sources, to provide relevant information from the user point of view. The information from the users' devices, due to its personal and credible character, works as a filter to the retrieved from other less trustable and structured sources. A preliminary evaluation, suggested that we can provide the user with inter-connected relevant information from heterogeneous sources. However, we found some limitations that led us to our current research challenges. João Guerreiro 0002, Tiago João Vieira Guerreiro, Daniel Gonçalves 0002 |
Mobile HCI | 1 |