Tiago Guerreiro

Tiago Guerreiro
University of Lisbon | UL · Department of Informatics

PhD

About

197
Publications
47,306
Reads
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1,581
Citations
Introduction
Tiago Guerreiro is an Assistant Professor at the University of Lisbon (Faculty of Sciences) and a researcher at LASIGE. His main areas of expertise are HCI, Pervasive Healthcare, Accessibility, and Mobile Computing. His research is focused on improving health, accessibility, and privacy, through and to technology, following a user-centred design approach. He has worked closely with people with motor, cognitive, and visual impairments, both in understanding their abilities, and in empowering them with alternative and adaptive interfaces. In these areas, he has published 75+ peer-reviewed papers. He received awards for 8 papers, including at CHI, ASSETS, SOUPS and MHCI, the flagship venues for HCI, Accessible Computing, Usable Privacy and Mobile HCI, and a Best of Computing award in 2016.
Additional affiliations
September 2005 - September 2012
Universidade Técnica de Lisboa
Description
  • Master and PhD Several research projects

Publications

Publications (197)
Conference Paper
Full-text available
The advent of system-wide accessibility services on mainstream touch-based smartphones has been a major point of inclusion for blind and visually impaired people. Ever since, researchers aimed to improve the accessibility of specific tasks, such text-entry and gestural interaction. However, little work aimed to understand and improve the overall ac...
Conference Paper
Full-text available
Unauthorized physical access to personal devices by people known to the owner of the device is a common concern, and a common occurrence. But how do people experience incidents of unauthorized access? Using an online survey, we collected 102 accounts of unauthorized access. Participants wrote stories about past situations in which either they acces...
Conference Paper
Full-text available
Typing on mobile devices is a common and complex task. The act of typing itself thereby encodes rich information, such as the typing method, the context it is performed in, and individual traits of the person typing. Researchers are increasingly using a selection or combination of experience sampling and passive sensing methods in real-world settin...
Preprint
Full-text available
When users leave their mobile devices unattended, or let others use them momentarily, they are susceptible to privacy breaches. Existing technological defenses, such as unlock authentication or account switching, have proven to be unpopular. We conducted interviews to uncover practices users currently engage in to cope with the threat, and found th...
Article
Full-text available
There is growing interest in monitoring gait patterns in people with neurological conditions. The democratisation of wearable inertial sensors has enabled the study of gait in free living environments. One pivotal aspect of gait assessment in uncontrolled environments is the ability to accurately recognise gait instances. Previous work has focused...
Article
Full-text available
Background Caregivers’ influence on young children’s eating behaviors is widely recognized. Nutritional interventions that focus on the promotion of children’s healthy diet should actively involve parents, focusing on their feeding behaviors and practices. Methods This work aims to describe the development and study protocol of the SmartFeeding4Ki...
Chapter
Poor eating habits are one of today’s significant menaces to public health. Child obesity is increasing, is a concerning reality, and needs to be appropriately addressed. However, most behavior change programs do not consider the needs of parents and their children, their profiles, and environments in the design of this type of intervention. We pre...
Conference Paper
Full-text available
Smartphones are shipped with built-in screen readers and other accessibility features that enable blind people to autonomously learn and interact with the device. However, the process is not seamless, and many face difficulties in the adoption and path to becoming more experienced users. In the past, games like Minesweeper served to introduce and t...
Conference Paper
Full-text available
Virtual environments for therapy are scarce and lack personalization. The creation of these environments is done by specialists, is time-consuming, and expensive. We present a smartphone tool that allows non-specialists to create navigable virtual environments by taking and linking sequences of panoramic photo spheres, analogly to Google Street Vie...
Conference Paper
Full-text available
Programming environments are now widely adopted in classrooms to teach programming concepts. However, these tools are often reliant on visual interaction, making them inaccessible to children with visual impairments. Also, programming environments in general are usually designed to promote individual experiences, wasting the potential benefits of g...
Article
Through a set of participatory design (PD) sessions with children with visual impairments and their educators, we understood current practices in maths teaching, and designed a novel system to support learning for this particular educational context. Sixteen children were engaged in 19 PD sessions to develop tangibles and auditory stimuli to repres...
Conference Paper
Full-text available
Accessible introductory programming environments are scarce, and their study within ecological settings (e.g., at home) is almost non-existent. We present ACCembly, an accessible block-based environment that enables children with visual impairments to perform spatial programming activities. ACCembly allows children to assemble tangible blocks to pr...
Article
Image description has been a recurrent topic on web accessibility over the years. With the increased use of social networks, this discussion is even more relevant. Social networks are responsible for a considerable part of the images available on the web. In this context, users are not only consuming visual content but also creating it. Due to this...
Article
In October 2020 was the 22nd edition of the ACM SIGACCESS Conference on Computers and Accessibility(ASSETS 2020), which took place online. The ASSETS conference is the premier computing research conferenceexploring the design, evaluation, and use of computing and information technologies to benefi t people withdisabilities and older adults. This ye...
Preprint
Full-text available
Touch data, and in particular text-entry data, has been mostly collected in the laboratory, under controlled conditions. While touch and text-entry data have consistently shown its potential for monitoring and detecting a variety of conditions and impairments, its deployment in-the-wild remains a challenge. In this paper, we present WildKey, an And...
Preprint
Full-text available
User-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...
Article
Accessibility assessments typically focus on determining a binary measurement of task performance success/failure; and often neglect to acknowledge the nuances of those interactions. Although a large population of blind people find smartphone interactions possible, many experiences take a significant toll and can have a lasting negative impact on t...
Article
Full-text available
Introduction: Functional mobility (FM) is a concept that incorporates the capacity of a person to move independently and safely to accomplish tasks. It has been proposed as a Parkinson's disease (PD) functional and global health outcome. In this study, we aimed to identify which kinematic and clinical outcomes changes better predict FM changes when...
Conference Paper
Full-text available
This talk builds on more than 14 years of deep engagements and in-the-wild deployments of mobile technologies within a community of blind people. It makes the case for pervasive assistive technology researchers to be experts in their areas of study: people, and then, technology to serve and empower people.
Preprint
Full-text available
Accessibility assessments typically focus on determining a binary measurement of task performance success/failure; and often neglect to acknowledge the nuances of those interactions. Although a large population of blind people find smartphone interactions possible, many experiences take a significant toll and can have a lasting negative impact on t...
Preprint
Full-text available
The landscape of digital games is segregated by player ability. For example, sighted players have a multitude of highly visual games at their disposal, while blind players may choose from a variety of audio games. Attempts at improving cross-ability access to any of those are often limited in the experience they provide, or disregard multiplayer ex...
Article
Full-text available
Mild cognitive impairment (MCI) is characterized by cognitive, psychological, and functional impairments. Digital interventions typically focus on cognitive deficits, neglecting the difficulties that patients experience in instrumental activities of daily living (IADL). The global conjecture created by COVID-19 has highlighted the seminal importanc...
Poster
Full-text available
Users are susceptible to privacy breaches when people close to them gain physical access to their phones. We present logging as a security response to this threat, one that is able to accommodate for the particularities of social relationships. To this end, and explore the feasibility of the logging approach, we present a prototype developed for An...
Conference Paper
Full-text available
The usage of playful activities is common in introductory programming settings. There is normally a virtual character or a physical robot that has to collect items or reach a goal within a map. Visually, these activities tend to be exciting enough to maintain children engaged: there is constant feedback about the actions being performed, and the vi...
Conference Paper
Full-text available
Games bring people together in immersive and challenging interactions. In this paper, we share multiplayer gaming experiences of people with visual impairments collected from interviews with 10 adults and 10 minors, and 140 responses to an online survey. We include the perspectives of 17 sighted people who play with someone who has a visual impairm...
Article
Full-text available
Blind 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...
Article
Full-text available
Background: Gait impairments are common and highly disabling for Parkinson's disease (PD) patients. With the development of technology-based tools, it is now possible to measure the spatiotemporal parameters of gait with a reduced margin of error, thereby enabling a more accurate characterization of impairment. Objective: To summarize and critic...
Conference Paper
Full-text available
Word 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 o...
Conference Paper
Full-text available
We present iCETA, an inclusive interactive system for math learning, that enables children to autonomously engage and solve additive composition tasks. It was designed through a set of participatory sessions with visually impaired children and their educators, and supports math learning through the combination of tangible interaction with haptic an...
Preprint
Full-text available
Blind people face significant challenges when using smartphones. The focus on improving non-visual 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 paper, we present a set of studies performed with the target population,...
Chapter
Mobile device users are required to constantly learn to use new apps, features, and adapt to updates. For blind people, adapting to a new interface requires additional time and effort. At the limit, and often so, devices and applications may become unusable without support from someone else. Using tutorials is a common approach to foster independen...
Chapter
Full-text available
Mobile devices are the tools of the trade to access services and contents on the Internet, already surpassing their desktop counterparts. These gadgets are always available and provide access to social networks, messaging, games, productivity tools, among many others. Accessing the Web with mobile devices, either through a browser or a native appli...
Conference Paper
Full-text available
Parkinson's disease is a progressive neurodegenerative disorder that is also characterized by its motor fluctuations throughout the day. This makes clinical assessment to be hard to accomplish in an appointment as the patient status at the time may be largely different from his condition two hours before. Clinicians can only evaluate patients from...
Conference Paper
Full-text available
Caregiving to a person with Alzheimer's can be a very demanding task, both from physical and psychological perspectives. Technological responses to support caregiving, and improve the quality of life of people with Alzheimer's and their caregivers are lacking. Using a research through design approach, we devised a robot focused on empowering people...
Conference Paper
Full-text available
Mobile device users are required to constantly learn to use new apps, features, and adapt to updates. For blind people, adapting to a new interface requires additional time and effort. At the limit, and often so, devices and applications may become unusable without support from someone else. Using tutorials is a common approach to foster independen...
Conference Paper
Full-text available
Monitoring of people with Parkinson is performed in appointments and through questionnaires. Traditional methods are still limited and imprecise in capturing motor fluctuations, which, for example, jeopardizes accurate medication adjustments. There have been several efforts to develop sensors and digitize these assessments, in the clinic and at hom...
Conference Paper
Full-text available
Non-pharmacological interventions for people with dementia benefit from the usage of personalized materials. These are not always easy to obtain. In a set of formative studies, we looked at how clinical staff and families recur to the usage of biographical elements to stimulate and foster the self-identity of people with dementia. Results showed th...
Poster
Full-text available
VIDEO: http://gaips.tagus.ist.utl.pt/~fcorreia/assetsVideoFinal.mp4 Our goal is to disseminate an exploratory investigation that examined how physical presence and collaboration can be important factors in the development of assistive robots that can go beyond information-giving technologies. In particular, this video exhibits the setting and proc...
Conference Paper
Full-text available
Blind people rely on sighted peers and different assistive technologies to accomplish everyday tasks. In this paper, we explore how assistive robots can go beyond information-giving assistive technologies (e.g., screen readers) by physically collaborating with blind people. We first conducted a set of focus groups to assess how blind people perceiv...
Conference Paper
The constant barrage of updates and novel applications to explore creates a ceaseless cycle of new layouts and interaction methods that we must adapt to. One way to address these challenges is through in-context interactive tutorials. Most applications provide onboarding tutorials using visual metaphors to guide the user through the core features a...
Conference Paper
Full-text available
Braille input enables fast nonvisual entry speeds on mobile touchscreen devices. Yet, the lack of tactile cues commonly results in typing errors, which are hard to correct. We propose Hybrid-Brailler, an input solution that combines physical and gestural interaction to provide fast and accurate Braille input. We use the back of the device for physi...
Conference Paper
Individuals regularly face challenges when interacting with their mobile devices particularly if they are not tech savvy users. When such difficulties occur, individuals often rely on more knowledgeable users to overcome difficulties. However, many do not have a support network of knowledgeable individuals available. Moreover, some challenges go be...
Conference Paper
Full-text available
Non-pharmacological interventions are the most common and arguably most effective for people with dementia. Some of these approaches have been proven to benefit from the usage of biographical or personalized materials. These contents are not always easy to obtain. Alongside, it is a challenge to maintain awareness of what is meaningful for a certai...
Conference Paper
Full-text available
Blind 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 ex...
Conference Paper
Full-text available
The physical keypads that used to dominate our mobile devices provided additional support for non-visual interaction-the keys could be recognized tactually, the interfaces were simpler and consistent. When combined with a screen reader, these devices could be easily operated by blind people. The advent of smartphones, with their rich, feature-fille...
Conference Paper
Full-text available
Facebook accounts are secured against unauthorized access through passwords and device-level security. Those defenses, however, may not be sufficient to prevent social insider attacks, where attackers know their victims, and gain access to a victim's account by interacting directly with their device. To characterize these attacks, we ran two MTurk...
Article
Full-text available
Over the last decade there have been numerous studies on touchscreen typing by blind people. However, there are no reports about blind users' everyday typing performance and how it relates to laboratory settings. We conducted a longitudinal study involving five participants to investigate how blind users truly type on their smartphones. For twelve...