Os softwares de Geometria Interativa (GI) foram desenvolvidos com o objetivo de possibilitar aos estudantes explorarem a geometria por meio do computador, permitindo a construção e manipulação de objetos geométricos, como retas, pontos e circunferências. Por meio da interface destes softwares, os estudantes são capazes de compreender e manipular os objetos geométricos, podendo influenciar na aprendizagem da geometria. Para Laborde (2007), os desenvolvedores de softwares de GI deveriam se preocupar com os aspectos pedagógicos e com o design da interface, pois, as interfaces indevidamente projetadas podem causar frustrações aos alunos, fazendo com que sintam dificuldade em utilizar o software e terminando por não direcionar o aprendizado da geometria. Apesar desta importância, há poucos estudos que investigam metodologias que relacionam os conceitos pedagógicos e os recursos computacionais. Além disto, há uma carência de pesquisas sobre diferentes tipos de interações disponíveis para a criação de interfaces para softwares de GI. A fim de preencher esta lacuna, este trabalho de mestrado tem como objetivo investigar metodologias para o desenvolvimento de gestos para interfaces gestuais em softwares de GI. É proposto um novo tipo de interação para estes softwares, com o objetivo de apoiar a aprendizagem da geometria por meio das interfaces gestuais. / The Interactive Geometry software (IG) were developed with the goal of enabling students to explore geometry through the computer, allowing the construction and manipulation of geometric objects, such as, lines, dots and circles. Through these interfaces software, students are able to understand and manipulate geometric objects, and may influence their learning of geometry. To Laborde (2007) , IG developers should worry about the pedagogic aspects and the design of the interface, because the improperly designed interfaces can make students to become frustrated, making them feel difficult to use the software and not focusing in the learning of geometry itself. Despite this importance, there are few studies investigating the pedagogical methodologies that relate concepts and computational resources. Furthermore, there is a lack of research about different types of interactions available for creating interfaces for IG software. In order to fill this gap, this master thesis aims to investigate methodologies for the development of gestures for gestural interfaces in GI software. It is proposed a new type of interaction for these software, aiming to support the learning of geometry.

Os softwares de Geometria Interativa (GI) foram desenvolvidos com o objetivo de possibilitar aos estudantes explorarem a geometria por meio do computador, permitindo a construção e manipulação de objetos geométricos, como retas, pontos e circunferências. Por meio da interface destes softwares, os estudantes são capazes de compreender e manipular os objetos geométricos, podendo influenciar na aprendizagem da geometria. Para Laborde (2007), os desenvolvedores de softwares de GI deveriam se preocupar com os aspectos pedagógicos e com o design da interface, pois, as interfaces indevidamente projetadas podem causar frustrações aos alunos, fazendo com que sintam dificuldade em utilizar o software e terminando por não direcionar o aprendizado da geometria. Apesar desta importância, há poucos estudos que investigam metodologias que relacionam os conceitos pedagógicos e os recursos computacionais. Além disto, há uma carência de pesquisas sobre diferentes tipos de interações disponíveis para a criação de interfaces para softwares de GI. A fim de preencher esta lacuna, este trabalho de mestrado tem como objetivo investigar metodologias para o desenvolvimento de gestos para interfaces gestuais em softwares de GI. É proposto um novo tipo de interação para estes softwares, com o objetivo de apoiar a aprendizagem da geometria por meio das interfaces gestuais. / The Interactive Geometry software (IG) were developed with the goal of enabling students to explore geometry through the computer, allowing the construction and manipulation of geometric objects, such as, lines, dots and circles. Through these interfaces software, students are able to understand and manipulate geometric objects, and may influence their learning of geometry. To Laborde (2007) , IG developers should worry about the pedagogic aspects and the design of the interface, because the improperly designed interfaces can make students to become frustrated, making them feel difficult to use the software and not focusing in the learning of geometry itself. Despite this importance, there are few studies investigating the pedagogical methodologies that relate concepts and computational resources. Furthermore, there is a lack of research about different types of interactions available for creating interfaces for IG software. In order to fill this gap, this master thesis aims to investigate methodologies for the development of gestures for gestural interfaces in GI software. It is proposed a new type of interaction for these software, aiming to support the learning of geometry.

Automatically recognizing gestures of the hand is a promising approach to communicating with computers, particularly when keyboard and mouse interactions are inconvenient, when only a brief interaction is necessary, or when a command involves a three-dimensional, spatial component. Which gestures are most convenient or preferred in various circumstances is unknown. This work explores the idea that perceived physical effort of a hand gesture influences users’ preference for using it when communicating with a computer. First, the hypothesis that people prefer gestures with less effort is tested by measuring the perceived effort and appeal of simple gestures. The results demonstrate that gestures perceived as less effortful are more likely to be accepted and preferred. The second experiment tests similar hypothesis with three-dimensional selection tasks. Participants used the tapping gesture to select among 16 targets in two environments that differ primarily in the physical distance required to finish the task. Participants, again, favor the less effortful environment over the other. Together the experiments suggest that effort is an important factor in user preference for gestures. The effort-to-reliability tradeoff existing in the majority of current gesture interfaces is then studied in experiment 3. Participants are presented 10 different levels of effort-to-reliability tradeoff and decide which tradeoff they prefer. Extreme conditions were intentionally avoided. On average they rate their preferred condition 4.23 in a 10-point scale in terms of perceived effort, and can achieve a success rate of approximately 70%. Finally, the question of whether pointing to objects enhances recall of their visuospatial position in a three-dimensional virtual environment is explored. The results show that pointing actually decreases memory relative to passively viewing. All in all, this work suggests that effort is an important factor, and there is an optimal balance for the effort-to-reliability tradeoff from a user’s perspective. The understanding and careful consideration of this point can help make future gesture interfaces more usable.

Sign language has largely been dismissed in gesture interface research on grounds of being a natural language. This essay argues that this has been premature. We begin with an overview of relevant literature in the fields of both gesture interface design and sign language, followed by a discussion of other graphical and text-based user interfaces in the context of language - effectively a short essay on language and metaphors in interface design, going into more detail why I believe dismissing sign languages based on their linguistic nature is a mistake. This is further explored in an example user interface that was designed by taking an insight from sign language as a starting point to replace the desktop metaphor and combining it with the discussed text-based interfaces to extend the WIMP paradigm. This experimental design was used as a way to pose questions to users about potential uses of gesture interfaces.