Affordances support interaction by suggesting actions, while anti-affordances discourage or complicate task execution. In this work, we focus on property-based affordances and anti-affordances arising from a device’s physical properties, such as form, texture, and volume. We investigate how the usability of a handheld device changes when the property-based affordance of its grip transitions into an anti-affordance through a shape change. In a workshop exploring the design space for such transitions, which we term ’Useful Uselessness,’ we gathered concept ideas for shape-changing grips that can complicate or interrupt a task. Implementing three representative examples allowed us to study these grips during an exemplary drilling task. Our results show that changes in grip property can be especially useful for task interruption. We found that task context matters, and that shape-change type and its property have to be carefully chosen. In summary, we show that dynamically adapted property-based affordances can be useful to interrupt tasks, while safety issues have to be kept in mind.

International audience

Humans can distinguish two short simultaneous touches on the forearm, called Two-Point Discrimination (2PD), starting at a distance of approximately 40 mm. However, similar insights are lacking for vibrotactile stimuli, which would be essential for designing ergonomic gesture wristbands. Thus, an oriented 2PD test was performed using vibrotactile actuators on the forearm placed around the wrist (transverse) and along the forearm (longitudinal). The results indicate that the orientation between two actuators cannot be robustly distinguished. Two simultaneous stimuli on the forearm can best be detected at 90 mm distance, with a success rate of up to 96% for transverse placement when the actuators are arranged around the wrist. In this case, the actuators are approximately placed opposite each other, looking at the wrist as a circle. Thus, an actuator arrangement around the wrist is most sufficient to distinguish between a single and two simultaneous vibrotactile stimuli.

We use simple stickers on a wooden board to create ubiquitous touch interaction.Resonant frequencies make the board vibrate, creating tactile feedback when touching the stickers.In an experiment, we used stickers of three sizes to create Resonant Sticker Buttons and varied the delay of the feedback.Both size and feedback delay influenced the perceived weight of the buttons.While higher latencies result in a heavier perceived button, larger button sizes result in lighter perceived buttons and perceived feedback strength, and vice versa.Our findings suggest that touch interfaces with buttons of varying sizes, weights, and vibration strengths can be created on everyday surfaces, such as tables, by simply using stickers and speakers.

Vibrations are the dominant way to create haptic feedback for interactive systems and are most often induced by vibrotactile actuators. However, virtual content created for augmented reality usually does not support that modality, instead relying mainly on visual and auditive output. Aiming to provide haptic feedback for augmented reality in cases where real vibrations cannot be used, we explore how vibrations can be felt using vision and audio only. In a user study, a virtual 10 x 10 cm white square-shaped cuboid was influenced by animation and/or sound to induce a haptic illusion when being touched. We were able to identify a specific range where the perception of vibration was significantly stronger and more realistic compared to all other values. This was the case if the virtual object’s edges were blurred up to a range of 0.4 cm or 0.6 cm, correspondingly accompanied by sounds, where the spectrum was cut off at a frequency of 256 Hz (for 0.4 cm) or 966 Hz (for 0.6 cm). With that, we aim to enrich augmented reality systems.

While traditional interfaces in human-computer interaction mainly rely on vision and audio, haptics becomes more and more important. Haptics cannot only increase the user experience and make technology more immersive, it can also transmit information that is hard to interpret only through vision and audio, such as the softness of a surface or other material properties. In this workshop, we aim at discussing how we could interact with technology if haptics is strongly supported and which novel research areas could emerge.

We present ThermoQuest, a self-contained wearable head-mounted display system for enhancing Virtual Reality experiences with temperature feedback. It’s constructed with commodity hardware elements, featuring 6 Peltier elements on the rim of the headset touching the users face. We explain the design and implementation of an affordable wearable thermal VR prototype build with commodity hardware. In a user study with 15 participants, we show evidence for a significant difference in reported presence in VR between thermal VR and control conditions (p > 0.017) in a counterbalanced experimental setup. We end with a discussion and use cases of the presented VR prototype and similar systems.

Collaborative Virtual Environments (CVEs) offer unique opportunities for human communication. Humans can interact with each other over a distance in any environment and visual embodiment they want. Although deictic gestures are especially important as they can guide other humans' attention, humans make systematic errors when using and interpreting them. Recent work suggests that the interpretation of vertical deictic gestures can be significantly improved by warping the pointing arm. In this paper, we extend previous work by showing that models enable to also improve the interpretation of deictic gestures at targets all around the user. Through a study with 28 participants in a CVE, we analyzed the errors users make when interpreting deictic gestures. We derived a model that rotates the arm of a pointing user's avatar to improve the observing users' accuracy. A second study with 24 participants shows that we can improve observers' accuracy by 22.9%. As our approach is not noticeable for users, it improves their accuracy without requiring them to learn a new interaction technique or distracting from the experience.

Human-Computer Integration (HInt) is an emerging paradigm in which computational and human systems are closely interwoven. Integrating computers with the human body is not new. however, we believe that with rapid technological advancements, increasing real-world deployments, and growing ethical and societal implications, it is critical to identify an agenda for future research. We present a set of challenges for HInt research, formulated over the course of a five-day workshop consisting of 29 experts who have designed, deployed and studied HInt systems. This agenda aims to guide researchers in a structured way towards a more coordinated and conscientious future of human-computer integration.

During physical games, we love to socially interact with other players through bluffing or giving them hits. This work aims to enrich AR characters by adding a suggestive behavior to them intended to playfully influence game decisions. In a user study, we evaluated such behaviors presented as body postures by animated card characters using an AR trading card game. Our results indicate that AR characters can indeed influence the player’s game decisions through postures that encourage or discourage to play a certain card. Our approach enriches the game design space, can make the game more interesting, and finally adds a social component to the game.

With the rise of the Internet of Things, home appliances become connected and they can proactively provide status information to users. Facing a steadily increasing number of notification sources, it is unclear how information from smart home devices should be provided without overloading the users’ attention. In this paper, we investigate the design of non-urgent smart home notifications using a smart plant system. Based on feedback from focus groups, we designed four notification types and compared them in an eight-week in-situ study. We show that notifications displayed on smart home devices are preferred to those received on smartphones. Event-based notifications are unobtrusive, actionable and are preferred to persistent notifications. We derive guidelines that address the need of being in control, opportune locations for notification delivery at opportune moments, notification blindness, the importance of discretizing continuous information, and combining related notifications.

Currently, (invisible) smart speech assistants, such as Siri, Alexa, and Cortana, are used by a constantly growing number of people. Moreover, Augmented Reality (AR) glasses are predicted to become widespread consumer devices in the future. Hence, smart assistants can easily become common applications of AR glasses, which allows for giving the assistant a visual representation as an embodied agent. While previous research on embodied agents found a user preference for a humanoid appearance, research on the uncanny valley suggests that simply designed humanoids can be favored over hyper-realistic humanoid characters. In a user study, we compared agents of simple versus more realistic appearance (seen through AR glasses) versus an invisible state-of-the-art speech assistants (see Figure 1). Our results indicate that a more realistic visualization is preferred as it provides additional communication cues, such as eye contact and gaze, which seem to be key features when talking to a smart assistant. But if the situation requires visual attention, e.g., when being mobile or in a multitask situation, an invisible agent can be more appropriate as they do not distract the visual focus, which can be essential during AR experiences.

Facial analysis applications are increasingly being applied to inform decision-making processes. However, as global reports of unfairness emerge, governments, academia and industry have recognized the ethical limitations and societal implications of this technology. Alongside initiatives that aim to formulate ethical frameworks, we believe that the public should be invited to participate in the debate. In this paper, we discuss Biometric Mirror, a case study that explored opinions about the ethics of an emerging technology. The interactive application distinguished demographic and psychometric information from people's facial photos and presented speculative scenarios with potential consequences based on their results. We analyzed the interactions with Biometric Mirror and media reports covering the study. Our findings demonstrate the nature of public opinion about the technology's possibilities, reliability, and privacy implications. Our study indicates an opportunity for case study-based digital ethics research, and we provide practical guidelines for designing future studies.

Current techniques for teaching spinal mobilisation follow the traditional classroom approach: an instructor demonstrates a technique and students attempt to emulate it by practising on each other while receiving feedback from the instructor. This paper introduces SpinalLog, a novel tangible user interface (TUI) for teaching and learning spinal mobilisation. The system was co-designed with physiotherapy experts to look and feel like a human spine, supporting the learning of mobilisation techniques through real-time visual feedback and deformation based passive haptic feedback. We evaluated Physical Fidelity, Visual Feedback, and Passive Haptic Feedback in an experiment to understand their effects on physiotherapy students' ability to replicate a mobilisation pattern recorded by an expert. We found that simultaneous feedback has the largest effect, followed by passive haptic feedback. The high fidelity of the interface has little effect, but it plays an important role in the perception of the system's benefit.

Games are a great objective for research on tangible and embodied interaction as they not only have a long tradition in both the analogue and the digital game domain; they also perfectly represent the tangible and the embodiment through the nature of game play. In this Studio, we will go beyond the analogue characteristics of board games, not just by adding a visual digital layer, but by examining new game play mechanics for board games through digital technology. We will do this by introducing a new role in board games as an immersed 'character' in the game. For this, we use a very specific technology (virtual reality live streaming from a miniature perspective) as a new lens on (existing) board games. Through experimentation with and exploration of existing board games through this new lens, we will conceptualize and prototype game play mechanics for this new notion of game participation.

Every day people rely on navigation systems when exploring unknown urban areas. Many navigation systems use multimodal feedback like visual, auditory or tactile cues. Although other systems exist, users mostly rely on a visual navigation using their smartphone. However, a problem with visual navigation systems is that the users have to shift their attention to the navigation system and then map the instructions to the real world. We suggest using in-situ navigation instructions that are presented directly in the environment by augmenting the reality using a projector-quadcopter. Through a user study with 16 participants, we show that using in-situ instructions for navigation leads to a significantly higher ability to observe real-world points of interest. Further, the participants enjoyed following the projected navigation cues.

For locomotion in Virtual Reality (VR), different approaches exist. While continuously moving across the ground through walking techniques or controller input is considered to be most similar compared to the way we move through physical space, this technique causes motion sickness and results in lack of spatial orientation. Teleportation has been shown to result in less motion sickness, while being slower than moving continuously in most virtual environments. World-in-miniature (WIM) allows the user for changing his/her viewpoint through picking and relocating his/her representing icon in a virtual miniature replica of the VR he/she is located in. To see if WIM may be an alternative locomotion technique to continuous motion, we compared the three locomotion techniques contentious motion, teleportation and, WIM (see Fig. 1). We found that WIM outperforms the other two techniques in navigation time for longer distances. Furthermore, it provides best spatial knowledge while causing least motion sickness among the compared methods. We conclude with proposing to provide VR users with a set of locomotion techniques that allows for continuous motion when only moving little, while WIM could be used for moving over longer distances and in environments that are difficult to oversee.

Fragments is an interactive installation that represents historical moments of Berlin's Potsdamer Platz. The installation is an embodied interaction where people walk into and bring through their body movements the installation to live.

We present a concept of AURA, an urban personal projection to initiate the communication. In this work, we focus on how to break the ice with strangers through technology in urban public space. The Aura, as an enliven spiritual pet, floats around user's feet. We introduce a simple interaction scenario, attracting a person who comes within personal distance of the user who carries the AURA. To break the ice between strangers, a projected butterfly as the Aura is moved toward a person who comes within 2m of the user, and then back and forth to attract that person. We believe that externalized interactive representation of the user in the form of a spiritual pet can ease and facilitate the communication, serve as a conversation starter, and make the interactions between people more fun.

Privacy notices aim to make users aware of personal data gathered and processed by a system. Body-worn cameras currently lack suitable design strategies for privacy notices that announce themselves and their actions tosecondary andincidental users, such as bystanders, when they are being used in public. Hypothesizing that the commonly used status LED is not optimal for this use case, due to being not sufficiently understandable, noticeable, secure and trustworthy, we explore design requirements of privacy notices for body-worn cameras. Following a two-step approach, we contribute incentives for design alternatives to status LEDs: Starting from 8 design sessions with experts, we discuss 8 physical design artifacts, as well as design strategies and key motives. Finally, we derive design recommendations of the proposed solutions, which we back based on an evaluation with 12 UX & HCI experts.

Increasing sophistication and ubiquity of digital devices is creating potential for the development of new kinds of actuated interfaces. In this paper, we explore the design space around movement as a form of gestural communication for information output, in simple actuated desktop devices. We were curious as to how people might envision interacting with autonomous technology in the office. Accordingly, we focused our attentions on one prevalent desktop object, an interactive lamp, with three actuated joints, which allowed us to explore the interaction space of such devices. We invited 13 participants to design and enact movements with the lamp to communicate 20 simple messages. We explored a subset of these generated gestures, using the lamp as a personal cueing device in an office setting with 14 new participants. We present our qualitative findings from both studies that let users imagine the usage of an interactive desktop lamp through actuation.

Although a large number of navigation support systems for visually impaired people have been proposed in the past, navigating through unknown environments is still a major challenge for visually impaired travelers. Existing systems provide navigation information through headphones, speakers or tactile actuators. In this paper, we propose to use small lightweight quadcopters instead to provide navigation information for people with visual impairments. Using a leashed or free-floating quadcopter, the user is navigated by the distinct sound that the quadcopter emits and a haptic stimulus provided by the leash. In a user with 14 visually impaired participants, we compared leashed quadcopter navigation, free-floating quadcopter navigation, and traditional audio navigation. The results show that compared to audio navigation, participants navigate significantly faster with a free-floating quadcopter and make fewer navigation errors using the quadcopter navigation methods.

While most current interactive surfaces use only the position of the finger on the surface as the input source, previous work suggests using the finger orientation for enriching the input space. Thus, an understanding of the physiological restrictions of the hand is required to build effective interactive techniques that use finger orientation. We conducted a study to derive the ergonomic constraints for using finger orientation as an effective input source. In a controlled experiment, we systematically manipulated finger pitch and yaw while performing a touch action. Participants were asked to rate the feasibility of the touch action. We found that finger pitch and yaw do significantly affect perceived feasibility and 21.1% of the touch actions were perceived as impossible to perform. Our results show that the finger yaw input space can be divided into the comfort and non-comfort zones. We further present design considerations for future interfaces using finger orientation.

Even though, three-dimensional representations of architectural models exist, experiencing these models like one would experience a fully constructed building is still a major challenge. With Virtual Reality (VR) it is now possible to experience a number of scenarios in a virtual environment. Also prototyping interactive architecture elements, which might be very expensive, becomes possible. Thus, researchers and designers can already start to define user interfaces for interactive architectural elements, before they were even built. However, it is still an open question how exactly VR technologies can support experiencing interactive architecture. To answer this question, we compared experiencing three-dimensional architectural models and interactive architectural elements through a 2D screen & mouse+keyboard navigation, an head mounted display (HMD) & keyboard navigation, and an HMD & walking for navigation. The results of our study show challenges and opportunities regarding the immersion of these experiences.

Large high-resolution displays (LHRDs) present new opportunities for interaction design in areas such as interactive visualization and data analytics. Design processes for graphical interfaces for LHRDs are still challenging. In this paper, we explore the design space of graphical interfaces for LHRDs by engaging in the creation of four prototypes for supporting office work. Specifically, we investigate how users can effectively manage application windows on LHRDs using four window alignment techniques: curved zooming, window grouping, window spinning and side pane navigation. We present the design and implementation of these window alignment techniques in a sample office application. Based on a mixed-methods user study of our prototypes, we contribute insights on designing future graphical interfaces for LHRDs. We show that potential users appreciate techniques, which enhance focus switching without changing the spatial relation between related windows.

Our eyes use multiple cues to perceive depth. Current 3D displays do not support all depth cues humans can perceive. While they support binocular disparity and convergence, no commercially available 3D display supports focus cues. To use them requires accommodation, i.e. stretching the eye lens when focusing on an individual distance. Previous work proposed multilayer and light field displays that require the eye to accommodate. Such displays enable the user to focus on different depths and blur out content that is out of focus. Thereby, they might ease the separation of content displayed on different depth layers. In this paper we investigate the effect of focus cues by comparing 3D shutter glasses with a multilayer display. We show that recognizing content displayed on a multilayer display takes less time and results in fewer errors compared to shutter glasses. We further show that separating overlapping content on multilayer displays again takes less time, results in fewer errors, and is less demanding. Hence, we argue that multilayer displays are superior to standard 3D displays if layered 3D content is displayed, and they have the potential to extend the design space of standard GUI.

Due to the rise of lifelog cameras, we have personal video data that is too large to be watched. Video indexing has the potential to provide meta-information for faster video search. This work aims to support lifelog video indexing through automated face priority rating. In a user study, we identified parameters that allow for rating the importance of persons in a video. We implemented these findings to automatically predict the person's importance in video. We show that our algorithm predicts similar person priority ratings like the participants had given. Hence, we contribute to video-based lifelogging through indicating, implementing, and testing face indexing rules that predict how important a person in a video is perceived. Our findings can help to build video players that support users navigating through their large video data and reviewing sequences that recall important moments of life.

With the advent of lifelogging cameras the amount of personal video material is massively growing to an extent that easily overwhelms the user. To efficiently review lifelog data, we need well designed video navigation tools. In this paper, we analyze which cues are most beneficial for lifelog video navigation. We show that the information kind determines the most appropriate cue in single cue systems, but that multicue approaches are more appreciated. These findings can inspire to design video players with multiple navigation cues, including time, place, persons, and events for easier and more efficient lifelog video retrieval.

Come and get creatively hands on with the next generation of stretch sensors! This studio will see participants familiarize themselves with, and devise exciting new uses for dielectric elastomer (DE) stretch sensors. Unlike normal stretch sensors, these skin-like sensors are highly durable and reliable. DE sensors can also be customised into nearly any shape or size, whilst being only 0.5mm thin makes them near undetectable to the wearer. After introducing the technology by walking through some easy to adapt examples, participants will be supported to express and test their ideas around stretchable interfaces through a collaborative maker session. Through attaching the sensors to our bodies or by modifying second hand garments, participants will explore the design opportunities of DE sensors. The session will culminate in a design crit of participants' application mock-ups and a discussion of opportunities for future interactive materials, garments, artefacts and environments.

Pixel densities are increasing rapidly. We can observe this trend in particular for mobile devices like smartphones and tablets. Previous work revealed an effect of pixel density on subjective feedback and objective performance only for low resolution cathode ray tube screens. It is unclear if this effect persists for the four times higher pixel densities of current mobile devices. Therefore, we conducted a study to compare four pixel densities with 359, 180, 120, and 90 pixels per inch. While participants performed three tasks involving images, text and videos on a tablet, we measured perceived effort, perceived visual quality, task completion time, error rate, and body pose. Our results show that the effect of the pixel density highly depends on the content. We found that only for text, the four pixel densities have clearly different perceived media qualities. Pixel density seems to have a smaller effect on perceived media quality for images and videos and we found no effect on objective measures. Results show that text should be displayed in high resolution, while this is less important for images and videos.

Distant pointing at objects and persons is a highly expressive gesture that is widely used in human communication. Pointing is also used to control a range of interactive systems. For determining where a user is pointing at, different ray casting methods have been proposed. In this paper we assess how accurately humans point over distance and how to improve it. Participants pointed at projected targets from 2m and 3m while standing and sitting. Testing three common ray casting methods, we found that even with the most accurate one the average error is 61.3cm. We found that all tested ray casting methods are affected by systematic displacements. Therefore, we trained a polynomial to compensate this displacement. We show that using a user-, pose-, and distant-independent quartic polynomial can reduce the average error by 37.3%

With an increasing number of new camera devices entering the market, lifelogging has turned into a viable everyday practice. The promise of comprehensively capturing our life's happenings has caused adoption rates to grow, but approaches to do so greatly differ. In this paper we evaluate existing visual lifelogging capture approaches through a user study with two main capture dimensions: (1) comparing the body position where a lifelogging camera is worn: head versus chest (2) comparing the media captures: video versus stills. We equipped 30 participants with cameras on their heads and chests. That data was evaluated by subjective user ratings as well as by objective image processing analysis. Our findings indicate that (1) chest-worn devices are more stable and contain less motion blur through which feature detection by image processing algorithms works better than from head-worn cameras; 2) head-worn video cameras, however, seem to be the better choice for lifelogging as they capture more important autobiographical cues than chest-worn devices, e.g., faces that have been shown to be most relevant for recall.

With the recent success of tablet devices a new device type became available for mobile interaction. Just as for mobile phones, touch is the dominant way people interact with tablets. In contrast to the much smaller phones a firm grip with both hands is needed to securely hold tablet devices. While a large body of work has investigated touch interaction on smaller devices, is little empirical research has been carried out on touch-based pointing while holding the device with both hands. To understand touch-based interactions using tablet devices, we conducted an experiment to compare four pointing techniques on both the front and back of the devices while it was held in landscape format. We compare direct touch with the following alternatives for selecting targets, indirect pointing on a virtual touchpad, an inverse cursor, and a miniature interaction area. While direct touch is 35% faster than the fastest alternative, only 74% of the touchscreen and 64% of a back-of-device can be reached by each hand. We show that among the indirect pointing techniques, the miniaturized interaction area is significantly faster and received the best subjective ratings. We conclude that a miniaturized interaction area is a viable alternative to direct touch especially on the backside of tablet devices.

The thumb and the fingers have different flexibility, and thus, gestures performed on the back of a held tablet are suggested to be different from ones performed on the touchscreen with the thumb of grasping hands. APIs for back-of-device gesture detection should consider that difference. In a user study, we recorded vectors for the four most common touch gestures. We found that drag, swipe, and press gestures are significantly differently when executed on the back versus on the front side of a held tablet. Corresponding values are provided that may be used to define gesture detection thresholds for back-of-tablet interaction.

Sensory hand augmentation extends the manual function spectrum from controlling analogue objects to digital or smart objects but also might add an interface to any graspable thing and therefore add a digital interface to everyday objects. We propose a finger-attached interface to control grasped objects intended to explore design parameters for always available interfaces. Our device detects finger motions and classifies them according to a set of five gestures. In user studies we found that our gesture classification has a stable performance with respect to different organic-shaped surfaces. Finally, the scalability of our approach towards generic object control will point out its potential.

We present a wearable interface that consists of motion sensors. As the interface can be worn on the user's fingers (as a ring) or fixed to it (with nail polish), the device controlled by finger gestures can be any generic object, provided they have an interface for receiving the sensor's signal. We implemented four gestures: tap, release, swipe, and pitch, all of which can be executed with a finger of the hand holding the device. In a user study we tested gesture appropriateness for the index finger at the back of a handheld tablet that offered three different form factors on its rear: flat, convex, and concave (undercut). For all three shapes, the gesture performance was equally good, however pitch performed better on all surfaces than swipe. The proposed interface is an example towards the idea of ubiquitous computing and the vision of seamless interactions with grasped objects. As an initial application scenario we implemented a camera control that allows the brightness to be configured using our tested gestures on a common SLR device.

This paper presents research how a finger-gesture design space for interacting with hand-held tablets may be defined. The parameters that limit or extend this space, such as anatomy-dependent gesture feasibility, grasp requirement, gesture occlusion or complexity, are discussed based on initial explorative expert interviews and following user studies. The goal of this research is defining parameters that have to be taken into account for developing a finger-gesture UI model for hand-held tablets. Although this model has a strong user-centric design approach, rather than being technology driven, technical solutions for detecting finger gestures are also considered. A model design is presented and research questions for investigating this model in greater detail are outlined.

The idea of capitalizing on the hand's degrees of freedom while grasping for gesture-based control motivates my research. The question is: to what extent can users interact with grasped objects through tiny finger gestures that are performed whilst grasping? This extended abstract is a position paper on developing a paradigm for interacting with everyday objects. I focus on designing ergonomic microinteractions and interfaces regarding human motor abilities, interaction preferences, and the understanding of the users themselves within their environment. The basis of the investigated interaction designs is a taxonomy for microgestures that is developed in an expert study. In proof-of-concept user studies with interactive prototypes, I evaluate microgesture-based interactions and generalize them to a post WIMP paradigm for interacting with grasped objects. The paradigm contains design implications for occluded gestures relying on embodied knowledge about grasping objects.

This paper focuses on combining front and back device interaction on grasped devices, using touch-based gestures. We designed generic interactions for discrete, continuous, and combined gesture commands that are executed without hand-eye control because the performing fingers are hidden behind a grasped device. We designed the interactions in such a way that the thumb can always be used as a proprioceptive reference for guiding finger movements, applying embodied knowledge about body structure. In a user study, we tested these touch-based interactions for their performance and users' task-load perception. We combined two iPads together back-to-back to form a double-sided touch screen device: the PinchPad. We discuss the main errors that led to a decrease in accuracy, identify stable features that reduce the error rate, and discuss the role of 'body schema' in designing gesture-based interactions where the user cannot see their hands properly.

In the search for novel and more expressive interaction techniques for mobile devices, bodily aspects such as movement, gesture, and touch based interfaces are prominent. For instance, touch-screen gestures have found widespread application in mobile device interfaces while bodily gestures involving device movement are successfully applied in gaming scenarios. Research systems increasingly explore other modalities, like pressure, free-hand and on body interaction in mobile settings. This has become possible through on-going developments that have made sensing and actuating technologies cheaper and more easily integrated in mobile and handheld devices. The turn towards experiential, embodied, and enacted perspectives on cognition and action has also contributed to a shift in what aspects of interaction to focus upon in interaction design. This has led HCIresearchers to explore not only how the whole human body can be taken into account in design, but also to explore new domains of application for instance in leisure, entertainment and public urban environments.

This paper explores how microinteractions as finger gestures allow executing a secondary task without interrupting the manual primary tasks such as driving a car or using a smart stylus. An analyses of Bock's Grip Taxonomy helps to identify manual primary tasks that have a huge benefit of not being interrupted by secondary tasks to control mobile applications and devices. This vision could offer the possibility to use the mobile phone safely while holding a steering wheel of the car as well as augment the functionality of a smart stylus such as change the stroke width without stopping to write or to draw.

Nowadays, mobile devices provide new possibilities for gesture interaction due to the large range of embedded sensors they have and their physical form factor. In addition, auditory interfaces can now be more easily supported through advanced mobile computing capabilities. Although different types of gesture techniques have been proposed for handheld devices, there is still little knowledge about the acceptability and use of some of these techniques, especially in the context of an auditory interface. In this paper, we propose a novel approach to the problem by studying the design space of gestures proposed by end-users for a mobile auditory interface. We discuss the results of this explorative study, in terms of the scope of the gestures proposed, the tangible aspects, and the users' preferences. This study delivers some initial gestures recommendations for eyes-free auditory interfaces.

Graphical user interfaces for mobile devices have several drawbacks in mobile situations. In this paper, we present Foogue, an eyes-free interface that utilizes spatial audio and gesture input. Foogue does not require visual attention and hence does not divert visual attention from the task at hand. Foogue has two modes, which are designed to fit the usage patterns of mobile users. For user input we designed a gesture language build of a limited number of simple but also easy to differentiate gesture elements.