Figure 1: Illustration of a remote social interaction between two users waving each other in an augmented environment.The users wearing a head-mounted display are represented by a realistic avatar, with additional progressively abstract avatars displayed to showcase the varying levels of realism used in the experiment.

Visual representations are perhaps the most important mode of human-computer and computer-mediated human-human interaction today. Nevertheless, we suggest, there is a lack of appropriate processes for their design. It seems, designers as much as researchers sometimes assume that visual representations are universally and intuitively comprehensible although evidence suggests otherwise, resulting in suboptimal designs. This article addresses the problem by proposing a human-centered design process for universal and intuitive pictograms. This process is grounded in semiotics, theories of intuitive interaction, and visual perception. Furthermore, it has been validated through empirical research and in practice. The article describes the process, it explains each step, and it provides examples. The result is detailed instructions that other designers, researchers, and businesses can adopt in their projects for designing more suitable visual representations.

Followers of the Quantified Self movement track, analyze and compare vital and environmental data to optimize themselves. It can be stressful to keep all the measured values under control when pursuing this ambitious way of life. Body weight can be an especially emotional issue for many people and slight differences can be perceived as lack of discipline, although little fluctuations are natural. In this paper, we present a tangible display for body weight, based on floor rigidity. It displays body weight without numbers, which makes it less suitable for comparisons, while still giving the user an idea about their weight. We describe the metaphorical foundations of the concept, as well as the development of two prototypes, which implement the envisioned full-body weighing experience. We demonstrate how the design of a display can influence the users' connotation of data.

We describe a presentation system based on the embodied metaphors of giving presentations: topics are picked up, one goes through a series of points, and comes to a conclusion. Technically, our system is based on body tracking and hand-worn RFID readers. Wearing these readers, users can activate topics in live presentations by picking up RFID-tagged mnemonic objects. Each topic can consist of multiple points, which are mapped to positions on stage. Users can activate a point (and its corresponding slide) by walking up to its position on stage. Various actions, triggered by constellations of handheld objects and movements on stage, are supported by the system. We conducted a series of informal user feedback sessions. Its results indicate that our system has strengths and weaknesses, depending on presenter style and presentation context.

Recipients of phone calls face a constant dilemma between ignoring calls at the possible expense of offending the caller, missing business opportunities or neglecting family members on one hand; and answering them at the expense of interrupting their train of thought or appearing rude and impolite towards others with whom they share a social activity on the other hand. We studied people's attitudes regarding these dilemmas, with emphasis on their social aspects. In a cross-cultural study, conducted in Israel and in Germany, we surveyed both caller and recipient attitudes towards answering mobile phone calls in various circumstances. The study also assessed the aspects of providing contextual information about a call prior to it being answered, including types of information deemed most valuable. The results emphasise the importance of social norms in affecting respondents’ attitudes towards making or accepting phone calls regardless of role (caller or recipient), gender or culture. We also found that the norms in the physical context (e.g. being in a meeting) prevailed over norms in the virtual context (e.g. the phone call). Cultural and gender differences did not affect the degree to which people were frustrated by insufficient information regarding the other party's context. However, these factors did affect the suggested design solutions to this problem. The research provides insight into the social aspects of the problem of interruptive mobile phone calls and towards designing applications that help users maintain politeness while handling the caller–recipient dilemma.

In this paper, we explore body language in mobile phones as a means of relational interaction. We describe a prototype that allows the simulation of proxemic reactions to the nearing hand of a user, ranging from affection to aversion, based on nearness-based input and shape change-based output. A user study is reported, which indicates that users were able to interpret the prototype's behavior drawing on animal parallels. It is concluded that proxemically reactive actuation may be a viable means of actively integrating the relationship between the user and the device into the interaction.

In this paper, we explore how direct physical cues of interpersonal nearness can be achieved in mobile phones. Exemplarily, we present three novel means of communication for mobile phones: grasping, kissing and whispering. Reviewing the related work, we point to a research gap in direct physical near-body actuation in mobile telecommunication. To assess this gap, we present three prototypes that implement the proposed novel means of communication. We present initial user comments on the prototypes, which point to acceptance issues. We conclude in a set of research questions for future explorations in this field.

In this paper, we present a qualitative comparison of different sketching techniques, assessing their suitability for co-designing interaction design with children. It presents a study conducted in an experimental field research, in which children aged 6-12 were engaged in a co-design process, aimed to the creation of novel communication devices or services that fit their particular needs. The study compared embodied, physical sketching (body storming that was documented as photo stories) with disembodied, drawn sketching (comics), as for their creative results, and how the children, reportedly, felt during the creation process. The results indicate that embodied sketching techniques were more suitable for the children, both as for the quality of the results, and for the subjective experience of the children while designing.

In this paper, we present a new shape-based display technique for mobile phones: A rotatory deformation of the phone's chassis, resulting in a tapering between the phone's front and back panel. It draws on proprioceptive skills of the human hand, which we hypothesize to be sensitive to paralellism and tapering of two opposing panels.

This paper introduces the Impatient Toaster, a kitchen appliance designed to motivate its owners to eat more often and in regular intervals: After not using it for a while, it signalizes hunger through nervous movements. This project sought to explore life-like behaviour as a means of increasing user's sympathy for everyday objects. We present a prototype that was informally tested with six participants in a situated user test. The results indicate that sympathy and perceived cuteness can arise from life-like movements that, as we propose, represent an object's will of its own. This work is part of a larger series of experiments in the Living Interfaces project, exploring ways in which reduced life-like movements can be beneficial for Human-Machine Interaction.

This paper presents the Digital Hourglass, an alarm clock that focuses on the amount of sleep, rather than wake-up times. It follows a simple approach, lighting one LED for each hour of sleep, and physically resembles the interaction with a conventional hourglass: Tilting the hourglass moves 'time' between its chambers, placing it in an upright position activates it, turning it by 180° snoozes it and placing it horizontally on a surface turns it off.

This paper describes a new interaction concept, which is based on customizable self-adhesive stickers with an integrated button, manufacturable at low cost. By pressing the button, users can execute specialized functionalities on their mobile phones, e.g. dialing phone numbers or accessing URLs. We present three usage scenarios and a proof-of-concept prototype.

In this paper we introduce a new way to interact intimately with an automated system. The Intimate Door Lock investigates the psychological effects of intimate humanhuman interaction being applied to man-machine interfaces. The door lock, in our prototype, is installed at the inside of a domestic front door, and remains locked until given a kiss by its owner. In our prototype, the element to be kissed is a camera-augmented mirror, which we intended to use as a means of lowering the inhibition level. This work is part of a larger series of experiments in the Living Interfaces project, exploring ways in which reduced life-like movements can be beneficial for Human-Machine Interaction.

In this paper, we present a novel type of persuasive home appliance: A thrifty water faucet. Through a servo motor construction, it is enabled to move and behave in life-like manners and to step into dialogue with the user. For example about water consumption or hygiene. We sought to research the reactions of users to such an appliance, alongside possible implications for the design of future human-machine interfaces.

This project explores the change of on-screen views through single-sided eye closure. A prototype was developed, three different applications are presented: Activating a sniper scope in a 3D shooter game, zooming out into a overview perspective over a web page, and filtering out icons on a cluttered desktop. Initial user testing results are presented.