Showing papers by "João Guerreiro published in 2013"

UbiBraille: designing and evaluating a vibrotactile Braille-reading device

Abstract: Blind 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.

The today and tomorrow of Braille learning

Abstract: Despite 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.

Blind People Interacting with Mobile Social Applications: Open Challenges

Abstract: Mobile devices are very important to blind people’s autonomy and social life. Likewise, Social Networking Sites (SNS) promote social inclusion and are widely used by blind people. Previous research already focused on the accessibility of mobile devices and SNS in separate; however, little effort has been made to understand the barriers that blind people face when interacting with mobile social applications. This paper describes two exploratory case studies, resorting to Technology Biographies, where two blind people demonstrated their usual interaction with social applications and stressed their difficulties and strategies. More than looking at the accessibility problems of a particular platform, we give a preliminary insight about the limitations and open research challenges that are transversal to these social applications.

Using simultaneous audio sources to speed-up blind people's web scanning

Abstract: Sighted users are able to sift through a website quickly to find their information of interest. In contrast, screen readers present the information sequentially to blind users, which contrast with the visual presentation on screen that portrays more information at once. We believe that blind users will benefit from multiple simultaneous sound sources while scanning websites with several information items, in order to find their information of interest faster.

Augmenting braille input through multitouch feedback

Abstract: Current touch interfaces lack the rich tactile feedback that allows blind users to detect and correct errors. This is especially relevant for multitouch interactions, such as Braille input. We propose HoliBraille, a system that combines touch input and multi-point vibrotactile output on mobile devices. We believe this technology can offer several benefits to blind users; namely, convey feedback for complex multitouch gestures, improve input performance, and support inconspicuous interactions. In this paper, we present the design of our unique prototype, which allows users to receive multitouch localized vibrotactile feedback. Preliminary results on perceptual discrimination show an average of 100% and 82% accuracy for single-point and chord discrimination, respectively. Finally, we discuss a text-entry application with rich tactile feedback.

Study of the effects of electrospun poly(epslon-caprolactone)/gelatin matrices on human mesenchymal stem cell culture

Abstract: ECM tridimensionality can be mimicked through the fabrication of nanofibrous scaffolds that can be used as a preliminary platform in skeletal muscle regeneration. This work aims at mimic the ECM structure through a comparative study between polycaprolactone (PCL), gelatin, PCL/gelatin and PCL/collagen electrospun nanofiber scaffolds for MSCs culture. The influence of different fiber alignments, diameters and scaffolds gelatin content on BM MSCs morphology and proliferation was investigated. AT and UCM MSCs morphology and proliferation were also assessed on nanofibrous scaffolds. In this study, the use of aligned scaffolds showed a significant effect on MSCs cells shape while gelatin presence in the scaffold resulted in a higher proliferation rate than in PCL (alone) scaffolds. PCL/gelatin and PCL/collagen scaffolds have demonstrate similar cellular proliferation which points out for possible collagen denaturation during polymer dissolution and electrospun. Moreover, MSCs showed to maintain their multilineage differentiation potential after culturing on the studied scaffolds.

Towards a fair comparison between name disambiguation approaches

Abstract: Searching for information about people in search engines is a common and straightforward task that is often hampered by name ambiguities. While users are interested in information about a single person, results pages usually comprise many persons with the same name. There are several approaches to tackle personal name disambiguation; however, it is still a challenge to understand the impact of each approach alone. In this paper, we present a plugin-based framework that aims to compare and to identify the most promising approaches for name disambiguation. This framework enabled us to merge different approaches to find good combinations for this task and to compare state-of-the-art solutions using a common dataset. Preliminary results support the greater impact of biographical information to aid in clustering, the use of comprehensive texts instead of only metadata and TF-IDF instead of more complex approaches.

"Tell me what I want to know!": the effect of relationship closeness on the relevance of profile attributes

Abstract: The growing amount of personal information on the web raises increasing concerns about what and with whom we share information online. Nevertheless, little effort has been made in determining the relevance of the information shared with us or in filtering it accordingly. We conducted a study to identify the most relevant characteristics when seeking information about people and to scrutinize their differences among relationship types. To achieve that, we asked users to describe people (friends, acquaintances and famous people). Afterwards, we asked them to rate the perceived relevance of a carefully pre-determined set of attributes for each type. Results showed that their relevance varied depending on the relationship. As an outcome, we present the most relevant attributes when seeking information about friends, acquaintances and famous people and the major differences among them. We conclude suggesting how our findings may influence the design of interactive systems where such data is paramount.