Publication statistics
Pub. period:2001-2012
Pub. count:12
Number of co-authors:12
Co-authors
Number of publications with 3 favourite co-authors:
Hugo Nicolau:9Tiago Guerreiro:8Daniel Goncalves:7 Productive colleagues
Joaquim Jorge's 3 most productive colleagues in number of publications:
Daniel Goncalves:28Tiago Guerreiro:15Hugo Nicolau:11 
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Joaquim Jorge
Publications by Joaquim Jorge (bibliography)
Nicolau, Hugo and Jorge, Joaquim (2012): Elderly text-entry performance on touchscreens. In: Fourteenth Annual ACM SIGACCESS Conference on Assistive Technologies 2012. pp. 127-134.
Touchscreen devices have become increasingly popular. Yet they lack of tactile feedback and motor stability, making it difficult effectively typing on virtual keyboards. This is even worse for elderly users and their declining motor abilities, particularly hand tremor. In this paper we examine text-entry performance and typing patterns of elderly users on touch-based devices. Moreover, we analyze users' hand tremor profile and its relationship to typing behavior. Our main goal is to inform future designs of touchscreen keyboards for elderly people. To this end, we asked 15 users to enter text under two device conditions (mobile and tablet) and measured their performance, both speed- and accuracy-wise. Additionally, we thoroughly analyze different types of errors (insertions, substitutions, and omissions) looking at touch input features and their main causes. Results show that omissions are the most common error type, mainly due to cognitive errors, followed by substitutions and insertions. While tablet devices can compensate for about 9% of typing errors, omissions are similar across conditions. Measured hand tremor largely correlates with text-entry errors, suggesting that it should be approached to improve input accuracy. Finally, we assess the effect of simple touch models and provide implications to design.
© All rights reserved Nicolau and Jorge and/or ACM Press
Oliveira, Joćo, Guerreiro, Tiago, Nicolau, Hugo, Jorge, Joaquim and Goncalves, Daniel (2011): Blind people and mobile touch-based text-entry: acknowledging the need for different flavors. In: Thirteenth Annual ACM SIGACCESS Conference on Assistive Technologies 2011. pp. 179-186.
The emergence of touch-based mobile devices brought fresh and exciting possibilities. These came at the cost of a considerable number of novel challenges. They are particularly apparent with the blind population, as these devices lack tactile cues and are extremely visually demanding. Existing solutions resort to assistive screen reading software to compensate the lack of sight, still not all the information reaches the blind user. Good spatial ability is still required to have notion of the device and its interface, as well as the need to memorize buttons' position on screen. These abilities, as many other individual attributes as age, age of blindness onset or tactile sensibility are often forgotten, as the blind population is presented with the same methods ignoring capabilities and needs. Herein, we present a study with 13 blind people consisting of a touch screen text-entry task with four different methods. Results show that different capability levels have significant impact on performance and that this impact is related with the different methods' demands. These variances acknowledge the need of accounting for individual characteristics and giving space for difference, towards inclusive design.
© All rights reserved Oliveira et al. and/or ACM Press
Guerreiro, Tiago Joćo Vieira, Nicolau, Hugo, Jorge, Joaquim and Goncalves, Daniel (2010): Assessing mobile touch interfaces for tetraplegics. In: Proceedings of 12th Conference on Human-computer interaction with mobile devices and services 2010. pp. 31-34.
Mobile touch-screen interfaces and tetraplegic people have a controversial connection. While users with residual capacities in their upper extremities could benefit immensely from a device which does not require strength to operate, the precision needed to effectively select a target bars these people access to countless communication, leisure and productivity opportunities. Insightful projects attempted to bridge this gap via either special hardware or particular interface tweaks. Still, we need further insight into the challenges and the frontiers separating failure from success for such applications to take hold. This paper discusses an evaluation conducted with 15 tetraplegic people to learn the limits to their performance within a comprehensive set of interaction methods. We then present the results concerning a particular interaction technique: Tapping. Results show that performance varies across different areas of the screen whose distribution changes with target size.
© All rights reserved Guerreiro et al. and/or their publisher
Nicolau, Hugo, Nunes, Renato and Jorge, Joaquim (2010): Personal mobile controller for blind people. In: Proceedings of 12th Conference on Human-computer interaction with mobile devices and services 2010. pp. 371-372.
We are moving towards a future where people will be ever more surrounded by technology and multiple appliances, bringing about the promise of truly intelligent environments. However, this multitude of devices raises several issues to HCI practitioners. Indeed, our preliminary studies confirm that blind people experience difficulties with most appliances, due to inadequate interfaces. The research described here approaches this problem by moving the user interface away from appliances to an intermediary device, which blind people are familiar with and can fully control. Additionally, we propose an automatic generation algorithm, which provides a consistent user interface to all appliances in the environment.
© All rights reserved Nicolau et al. and/or their publisher
Guerreiro, Tiago, Nicolau, Hugo, Jorge, Joaquim and Goncalves, Daniel (2010): Towards accessible touch interfaces. In: Twelfth Annual ACM SIGACCESS Conference on Assistive Technologies 2010. pp. 19-26.
Touch screen mobile devices bear the promise of endless leisure, communication, and productivity opportunities to motor-impaired people. Indeed, users with residual capacities in their upper extremities could benefit immensely from a device with no demands regarding strength. However, the precision required to effectively select a target without physical cues creates problems to people with limited motor abilities. Our goal is to thoroughly study mobile touch screen interfaces, their characteristics and parameterizations, thus providing the tools for informed interface design for motor-impaired users. We present an evaluation performed with 15 tetraplegic people that allowed us to understand the factors limiting user performance within a comprehensive set of interaction techniques (Tapping, Crossing, Exiting and Directional Gesturing) and parameterizations (Position, Size and Direction). Our results show that for each technique, accuracy and precision vary across different areas of the screen and directions, in a way that is directly dependent on target size. Overall, Tapping was both the preferred technique and among the most effective. This proves that it is possible to design inclusive unified interfaces for motor-impaired and able-bodied users once the correct parameterization or adaptability is assured.
© All rights reserved Guerreiro et al. and/or their publisher
Nicolau, Hugo, Guerreiro, Tiago, Jorge, Joaquim and Goncalves, Daniel (2010): Proficient blind users and mobile text-entry. In: Proceedings of the 2010 Annual European Conference on Cognitive Ergonomics 2010. pp. 19-22.
Motivation -- Understand how NavTap, an assistive text-entry method, stands in relation to traditional approaches. Research approach -- We performed a between-subjects text-entry study with 12 blind users proficient with MultiTap and five blind users proficient with NavTap. Participants were asked to input ten sentences with different length and complexity. Findings/Design -- MultiTap significantly outperformed NavTap when considering text entry speed, confirming its theoretical advantage. However, when considering method effectiveness, NavTap's less experienced participants committed significantly fewer errors, indicating that it is both easier to learn and use, reaffirming it is an alternative for those unable to adjust to demanding adaptations. Research limitations/Implications -- Before NavTap appeared its users were unable to input text in a mobile device. Indeed, existing data make it difficult to assess differences between the users of either method. Further, NavTap users had less experience using the method (four months) than MultiTap (years). Originality/Value -- We contribute to understanding the limitations and merits of different text-entry approaches for blind people, after extensive usage. Take away message -- Different methods have different limitations and values. Selecting a match for a particular user may depend on his individual differences.
© All rights reserved Nicolau et al. and/or their publisher
Guerreiro, Tiago, Jorge, Joaquim and Goncalves, Daniel (2010): Identifying the relevant individual attributes for a successful non-visual mobile experience. In: Proceedings of the 2010 Annual European Conference on Cognitive Ergonomics 2010. pp. 27-30.
Motivation -- To understand the individual differences with the greatest impact on a blind user's mobile interaction effectiveness and learning abilities. Research approach -- We performed a semi-structured interview to 10 specialized professionals (psychologists, occupational therapists, rehabilitation technicians, IT teacher) working closely with blind users. Findings/Design -- Results suggest that peripheral sensitivity, spatial ability, blindness onset age, age, intelligence and memory are the characteristics affecting user capabilities the most. Research limitations/Implications -- This study offers a wide view on the possible influencing attributes. Empirical studies are required to dissect the impact of each characteristic in mobile blind users' performance. Originality/Value -- We contribute with an understanding of the individual differences among the blind population that may affect mobile interaction. Take away message -- Individual differences among the blind have greater impact than those between sighted users. Understanding these differences is mandatory.
© All rights reserved Guerreiro et al. and/or their publisher
Pereira, Rita, Guerreiro, Tiago, Nicolau, Hugo, Goncalves, Daniel and Jorge, Joaquim (2010): Laying the groundwork for assisted rehabilitation. In: Proceedings of the 2010 Annual European Conference on Cognitive Ergonomics 2010. pp. 147-150.
Motivation -- To provide to physical therapists a monitoring system with effective and accurate patient monitoring and evolution analysis. Research approach -- We analyzed therapy sessions with tetraplegic patients to better understand the rehabilitation process and highlight the major requirements for a technology-enhanced tool. We developed a prototype able to automate and improve the current monitoring and follow-up processes. Findings/Design -- Preliminary results indicate that computational movement analysis and comparison can improve the quality of a rehabilitation session and overall patient evolution analysis. Research limitations/Implications -- Analysis and studies have been performed in a rehabilitation centre with a limited set of therapists (3) and patients (7). Originality/Value -- The research herein contributes with a requirement analysis for a computer-assisted rehabilitation platform. We present a tracking-based system instantiating these requirements and outline its values after a preliminary informal validation. Take away message -- The capture and virtual playback of motion in physical therapy sessions increases therapist awareness of patient condition and evolution thus improving the rehabilitation process.
© All rights reserved Pereira et al. and/or their publisher
Nicolau, Hugo, Jorge, Joaquim and Guerreiro, Tiago (2009): Blobby: how to guide a blind person. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 3601-3606.
For the majority of blind people, walking in unknown places is a very difficult, or even impossible, task to perform, when without help. The adoption of the white cane is the main aid to a blind user's mobility. However, the major difficulties arise in the orientation task. The lack of reference points and the inability to access visual cues are its main causes. We aim to overcome this issue allowing users to walk through unknown places, by receiving a familiar and easily understandable feedback. Our preliminary contributions are in understanding, through user studies, how blind users explore an unknown place, their difficulties, capabilities and needs. We also analyzed how these users create their own mental maps, verbalize a route and communicate with each other. Structuring and generalizing this information, we were able to create a prototype that generates familiar and adequate instructions, behaving like a blind companion, one with similar capabilities that understands his "friend" and speaks the same language. We evaluated the system with the target population, validating our approach and orientation guidelines, while gathering overall user satisfaction.
© All rights reserved Nicolau et al. and/or ACM Press
Guerreiro, Tiago, Nicolau, Hugo, Jorge, Joaquim and Goncalves, Daniel (2009): NavTap: a long term study with excluded blind users. In: Eleventh Annual ACM SIGACCESS Conference on Assistive Technologies 2009. pp. 99-106.
NavTap is a navigational method that enables blind users to input text in a mobile device by reducing the associated cognitive load. In this paper, we present studies that go beyond a laboratorial setting, exploring the methods' effectiveness and learnability as well as its influence on the users' daily lives. Eight blind users participated in designing the prototype (3 weeks) while five took part in the studies along 16 more weeks. Results gathered in controlled weekly sessions and real life usage logs enabled us to better understand NavTap's advantages and limitations. The method revealed itself both as easy to learn and improve. Indeed, users were able to better control their mobile devices to send SMS and use other tasks that require text input such as managing a phonebook, from day one, in real-life settings. While individual user profiles play an important role in determining their evolution, even less capable users (with age-induced impairments or cognitive difficulties), were able to perform the assigned tasks (sms, directory) both in the laboratory and in everyday use, showing continuous improvement to their skills. According to interviews, none were able to input text before. Nav-Tap dramatically changed their relation with mobile devices and noticeably improved their social interaction capabilities.
© All rights reserved Guerreiro et al. and/or their publisher
Fernandes, Vitor, Guerreiro, Tiago, Araśjo, Bruno, Jorge, Joaquim and Pereira, Joćo (2007): Extensible middleware framework for multimodal interfaces in distributed environments. In: Proceedings of the 2007 International Conference on Multimodal Interfaces 2007. pp. 216-219.
We present a framework to manage multimodal applications and interfaces in a reusable and extensible manner. We achieve this by focusing the architecture both on applications' needs and devices' capabilities. One particular domain we want to approach is collaborative environments where several modalities and applications make it necessary to provide for an extensible system combining diverse components across heterogeneous platforms on-the-fly. This paper describes the proposed framework and its main contributions in the context of an architectural application scenario. We demonstrate how to connect different non-conventional applications and input modalities around an immersive environment (tiled display wall).
© All rights reserved Fernandes et al. and/or their publisher
Heller, Rachelle, Jorge, Joaquim and Guedj, Richard (2001): EC/NSF workshop on universal accessibility of ubiquitous computing: providing for the elderly event report. In: Proceedings of the 2001 EC/NSF Workshop on Universal Accessibility of Ubiquitous Computing 2001. pp. 1-10.
The workshop took place on Alcįcer do Sal, Portugal from May 22nd to May 25th, 2001 with the purpose to discuss approaches to universal usability for the elderly constituency. Elderly citizens are a growing age group within developed countries and their needs have been mostly ignored by Information Technology and Computing as a whole. The surge of mobile communications and universal access materialized in the push for UMTS in Europe provided a strong leitmotif for this meeting. For the better part of a week, a group joining twenty-six people from several different communities gathered to discuss strategic issues arising from the new context. The aim is to provide strategic inputs for major research programs in EU, USA and Japan. The present document contains a summary account of the proceedings.
© All rights reserved Heller et al. and/or ACM Press
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