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Decades of online fashion retail and investment in its usability have led to a seemingly refined user experience. Yet, our study shows that female online shoppers, who make up the largest user group, experience a conflicted love-hate relationship when shopping online. Adopting a feminist HCI perspective, we contribute insights from a multi-step qualitative approach involving probes, co-design, iterative prototyping and body maps. We demonstrate that even screen-based website designs are deeply entangled with users’ embodied experiences. Through our analysis, we identify where such designs contribute to heightened emotional labour and negative user experiences. Our work offers concrete design implications centred around inclusivity, the predictive user experience of wearing and caring for garments, and transparency of information. We embody these implications in an interactive prototype and use it to validate our recommendations for a body-centred approach to UX design.

Interactive technology design is situated within environmental and sociocultural context. This pictorial develops an In-Situ Seeding method for engaging with site-specific sensory experiences. This method stems from a previous TEI Studio, where we utilized Sensory Portfolios, digital sensors, and other materials to make sense of interaction in place. We present an annotated collection of our Studio experiences and autobiographical retrospective reflections. These Seeds supported in-situ sensory explorations and examination of entanglements between documentation, data, location, history, and human and more-than-human agents. We contribute to literature around (1) walk-and-talk sensory explorations, (2) situated entanglements with technological artifacts, and (3) relationships between human and non-human agents in shared locations and over varied timescales. Our reflections point towards continued development for In-Situ Seeding as a method and suggest its further use and guidance to support future sensory explorers.

Augmented Reality (AR) is promising in providing individual learning support for students.However, it is currently unknown which display technology is appropriate to use in classroom settings.In this work, we investigate different AR displays and their usability

As HCI research turns to women's reproductive health as a topic of interest, an increasing number of female-oriented technologies (FemTech) are being marketed to consumers.This opens up a space for better management and understanding of intimate health but is not without risk.Reproductive health data collected by FemTech devices is highly sensitive and politicized.Breaches of privacy can cause or exacerbate discrimination and gender inequality, and negatively impact users' safety and well-being.It is therefore important that users are well informed about how their data is collected, handled, used and stored.This work contributes insights into whether and to what extent this is achieved by current FemTech.We conduct a structured content analysis of 18 in-effect privacy policies.Applying an empirically-grounded taxonomy, we identify challenges in policy wording, content and presentation.We conclude with recommendations for improving transparency and supporting users in providing informed consent and claiming data authority. CCS Concepts• Security and privacy → Privacy protections; Usability in security and privacy; Information accountability and usage control; • Social and professional topics → Women.

Despite the wide adoption of wearables, electronics incorporated into jewellery remain a niche. Interactive jewellery offers a compelling design space, encompassing values of traditional jewellery and its socio-cultural roles. However, creating interactive artefacts that bear symbolic and social meaning remains challenging. We investigate how these roles can be leveraged and re-interpreted using modern technology. Utilising traditional jewellery’s socio-cultural roles as a framework, we look at interactive jewellery in participatory workshops with N = 16 design practitioners. Informed by our results, we created a prototype interactive necklace, focusing on Identity role and conducted four case studies to probe the wearer and bystander perceptions on interactive jewellery in different social contexts. Based on our findings, we contribute four directions for interactive jewellery designers.

The design of interactive systems and digital artefacts often makes use of digital or analog sensory data as a way to “capture” human senses and sensory experiences. Yet, designing for and with sensory data is complex because of our unique, embodied ways of making sense of our somatosensory experiences. Sensory data does not have one prescribed meaning for everyone. We propose a one-day Studio at TEI to start a dialogue about work with sensory data and its representation of human sensory experience. Specifically, we propose a guided walk and series of sensory explorations in Bordeaux to contemplate the interplay between first-person somatosensory experiences and streams of site-specific data from various sensors. By walking and noticing together, this Studio invites participants to engage in a process of creative reflection on their felt experiences, their connection to their surroundings, and their stance within or outside the design community.

Smart homes are evolving into complex ecosystems, but their inner workings often remain opaque to users, limiting their ability to troubleshoot and customise the technology. The distributed and hidden components make it challenging for users to understand how these systems work. To design interfaces that enable intuitive troubleshooting for non-experts, we first need a clear understanding of how they form mental models and instinctively diagnose issues. We conducted three iterative vignette studies with realistic smart home scenarios to explore how users perceive interconnectivity in smart home ecosystems and how system complexity impacts their troubleshooting approaches. We identified common smart home topologies envisioned by users and categorised their diagnostic strategies. Our findings show that while users view their smart homes as hierarchical, their mental models are often incomplete, and current interfaces favour functional models, hiding the connections in the system. We provide seven actionable takeaways for designing interfaces that improve user understanding and troubleshooting capabilities.

Small-size autonomous vehicles have reached a level of technological maturity that enables their use as efficient means for goods delivery. Yet, current designs of both ground and aerial vehicles fail to address potential information needs of bystanders: What is this robot doing? Can it harm me? Does it need help? Through a series of six co-design workshops ( \(N = 22\) ), we iteratively explore two types of autonomous healthcare delivery vehicles, namely aerial and ground robots, with a focus on bystanders’ perspectives and interaction needs between bystanders and AVs. The resulting design propositions were then synthesized into functional scale-model prototypes of a healthcare delivery robot and drone. We validate our co-design findings by conducting two laboratory Wizard-of-Oz experiments ( \(N = 24\) ). Our results demonstrate how familiar colors and iconography support goal sharing and bystanders in recognizing the delivery vehicle’s purpose and intentions. Mapping interaction needs of bystanders, we find contextual effects on bystander attitudes and the effectiveness of communication modalities. This work contributes to the design of future, socially acceptable small-size delivery vehicles fit for human spaces.

The ‘material turn’ in Human Computer Interaction (HCI) is increasingly drawing attention to the computational affordances of materials and how we can craft with them. In this paper, we explore opportunities for combining the maker cultures of hand spinning with e-textile crafting. In our first study, we interviewed 32 hand spinners on their practices to better understand their motivations for spinning their own yarns and the techniques they use to do so. In our second study, we conducted workshops with 6 spinners at a local spinning guild, where participants worked with the conductive fibers and spun e-textile yarns. After the workshops, we conducted follow-up interviews with each participant to understand the opportunities and tensions of hand spinning e-textile yarns. Our findings show how spinners can blend local materials with conductive ones to develop their own custom interactive textiles, and the mismatch between how these fibers are sold and what information spinners require to inform their design decisions. Through these results, we hope to empower makers and inspire the design community to develop tools to support these DIY practices.

Electrical Muscle Stimulation (EMS) has unique capabilities that can manipulate users’ actions or perceptions, such as actuating user movement while walking, changing the perceived texture of food, and guiding movements for a user learning an instrument. These applications highlight the potential utility of EMS, but such benefits may be lost if users reject EMS. To investigate user acceptance of EMS, we conducted an online survey (N = 101). We compared eight scenarios, six from HCI research applications and two from the sports and health domain. To gain further insights, we conducted in-depth interviews with a subset of the survey respondents (N = 10). The results point to the challenges and potential of EMS regarding social and technological acceptance, showing that there is greater acceptance of applications that manipulate action than those that manipulate perception. The interviews revealed safety concerns and user expectations for the design and functionality of future EMS applications.

HCI research has been instrumental in enabling self-directed health tracking. Despite a plethora of devices and data, however, users’ views of their own health are often fragmented. This is a problem for women’s health, where physical and mental observations and symptoms are strongly intertwined. An integrated view throughout different life stages could help to better understand these connections, facilitate symptom alleviation through life-style changes, and support timely diagnosis: currently, women’s health issues often go under-researched and under-diagnosed. To capture the needs and worries of self-directed tracking, interpreting and sharing women’s health data, we held workshops with 28 women. Drawing upon feminist methods, we conducted a Reflexive Thematic Analysis to identify six central themes that ground opportunities and challenges for life-long, self-directed tracking of intimate data. These themes inform the design of tools for data collection, analysis and sharing that empower women to better understand their bodies and demand adequate health services.

Remote tutoring has gained significant traction due to technological advances, primarily relying on video-conferencing tools. However, these tools are not specifically designed for tutoring. Positive tutoring experiences rely on interaction with and immediate feedback from the tutor. Moreover, traditional methods like writing, reading, and drawing in physical spaces enhance learning outcomes. Integrating these methods with physical materials and digital remote guidance could improve remote learning experiences. A technology that enables this integration is spatial augmented reality (SAR), which utilizes projection to integrate digital content into the physical world. This work introduces a Spatial Augmented Reality (SAR) remote tutoring tool that enables augmented annotations and projected video streams. We conducted a between-subject lab study (N=18) comparing learning experiences in remote tutoring between standard video conferencing tools and the introduced Spatial Augmented Reality (SAR) tool. Qualitative analysis revealed the Spatial Augmented Reality (SAR) system's benefits over video conferencing, specifically immediate feedback, in-situ annotations, improved interactivity, and enhanced social presence.

Welcome to this issue of the Proceedings of the ACM on Human-Computer Interaction, which brings together contributions from the Mobile Human-Computer Interaction (MHCI) community. This issue showcases innovations in research focused on mobile, wearable, and personal devices. Research in MHCI encompasses both technical innovations and social considerations. Mobile technologies accompany us throughout our daily lives: at home, at work, in traffic, and out in the wild. However, while mobile technologies provide the capacity for constant connectivity, they also pose risks of harm and unintended consequences. There has never been a more pressing time to debate and explore the meaning of digital culture, and to understand how mobile technologies can and should be used to connect us, our data, and mobile applications and services in meaningful ways - true to the conference theme of 'Connecting Cultures'.

The vision of a ‘metaverse’ may soon bring a ubiquitous(ly) Augmented Reality (UAR) delivering context-aware, geo-located, and continuous blends of real and virtual elements into reach. This paper draws on speculative design to explore, question, and problematize consequences of AR becoming pervasive. Elaborating on Desjardin et al.’s bespoke booklets, we co-speculate together with 12 globally dispersed participants. Each participant received a custom-made design workbook containing pictures of their immediate surroundings, which they elaborated on in situated brainstorming activities. We present an integration of their speculative ideas and lived experiences in 3 overarching themes from which 7 ‘dark’ scenarios caused by UAR were formed. The Scenarios are indicative of deceptive design patterns that can (and likely will be) devised to misuse UAR, and anti-patterns that could cause unintended consequences. These contributions enable the timely discussion of potential antidotes and to which extent they can mitigate imminent harms of UAR.

Mid-air gesture-based systems are becoming ubiquitous. Many mid-air gestures control different kinds of interactive devices, applications, and systems. They are, however, still targeted at specific devices in specific domains and are not necessarily consistent across domain boundaries. A comprehensive evaluation of the transferability of gesture vocabulary between domains is also lacking. Consequently, interaction designers cannot decide which gestures to use for which domain. In this systematic literature review, we contribute to the future research agenda in this area, based on an analysis of 172 papers. As part of our analysis, we clustered gestures according to the dimensions of an existing taxonomy to identify their common characteristics in different domains, and we investigated the extent to which existing mid-air gesture sets are consistent across different domains. We derived a consensus gesture set containing 22 gestures based on agreement rates calculation and considered their transferability across different domains.

Wearable robotic arms (WRA) open up a unique interaction space that closely integrates the user’s body with an embodied robotic collaborator. This space affords diverse interaction styles, including body movement, hand gestures, or gaze. Yet, it is so-far unexplored which commands are desirable from a user perspective. Contributing findings from an elicitation study (N=14), we provide a comprehensive set of interactions for basic robot control, navigation, object manipulation, and emergency situations, performed when hands are free or occupied. Our study provides insights into preferred body parts, input modalities, and the users’ underlying sources of inspiration. Comparing interaction styles between WRAs and off-body robots, we highlight how WRAs enable a range of interactions specific for on-body robots and how users use WRAs both as tools and as collaborators. We conclude by providing guidance on the design of ad-hoc interaction with WRAs informed by user behavior.

Personal fabrication has mostly focused on handheld tools as embodied extensions of the user, and machines like laser cutters and 3D printers automating parts of the process without intervention. Although interactive digital fabrication has been explored as a middle ground, existing systems have a fixed allocation of user intervention vs. machine autonomy, limiting flexibility, creativity, and improvisation. We explore a new class of devices that combine the desirable properties of a handheld tool and an autonomous fabrication robot, offering a continuum from manual and assisted to autonomous fabrication, with seamless mode transitions. We exemplify the concept of mixed-initiative physical sketching with a working robotic printer that can be handheld for free-hand sketching, can provide interactive assistance during sketching, or move about for computer-generated sketches. We present interaction techniques to seamlessly transition between modes, and sketching techniques benefitting from these transitions to, e.g., extend (upscale, repeat) or revisit (refine, color) sketches. Our evaluation with seven sketchers illustrates that RoboSketch successfully leverages each mode’s strengths, and that mixed-initiative physical sketching makes computer-supported sketching more flexible.

Over the last decade, smart home technology (SHT) has become an integral part of modern households. As a result, smart home ecosystems blend with daily social life, appropriated and integrated into personalised domestic environments. The lived experience of inhabiting smart home ecosystems, however, is not yet understood, resulting in a mismatch between ecosystem design and inhabitants’ needs. Drawing on contextual inquiry methods, we conducted an explorative interview study (N=20) with SHT users in their homes. Our thematic analysis reveals how users shape their smart home ecosystems (SHEs), considering social relationships at home, perceived ownership of SHTs, and expected key benefits. Notably, our analysis shows that household members consciously choose ‘their’ level of SHT interconnectedness, reflecting social, spatial and functional affinities between systems. Following our findings, we formulate five implications for designing future SHTs. Our work contributes insights on the dynamics and appropriation of smart home ecosystems by their inhabitants.

Living bio-materials are increasingly used in HCI for fabricating objects by growing. However, how to integrate electronics to make these objects interactive still needs to be clarified. This paper presents an exploration of the fabrication design space of Biohybrid Interactive Devices, a class of interactive devices fabricated by merging electronic components and living organisms. From the exploration of this space using bacterial cellulose, we outline a fabrication framework centered on the biomaterials‘ life cycle phases. We introduce a set of novel fabrication techniques for embedding conductive elements, sensors, and output components through biological (e.g. bio-fabrication and bio-assembling) and digital processes. We demonstrate the combinatory aspect of the framework by realizing three tangible, wearable, and shape-changing interfaces. Finally, we discuss the sustainability of our approach, its limitations, and the implications for bio-hybrid systems in HCI.

Road traffic is strongly regulated, however informal communication is essential whenever formal rules are flexibly treated. Consequently, conflict-avoidant automated vehicles (AVs) can be disadvantaged when humans do not behave prosocially towards them. This can lead to disruptions of mixed traffic, where human and automated driving co-exists. Equipping AVs with sympathy-eliciting external Human-Machine Interfaces (eHMI) mimicking informal communication cues could mitigate this challenge by fostering the prosocial behavior of drivers. This work contributes video vignettes that are experimentally validated in an online survey (N=90). While we found participants to not behave differently towards human-controlled and baseline automated vehicles, eHMIs were potent in eliciting sympathy and encouraged yielding behavior. This effect was more pronounced when the interface signaled an urgent situation or indicated prolonged waiting times. Non-yielding behavior was rationalized based on priority rules. These results emphasize how fostering prosocial behavior in traffic can be achieved via sympathy-eliciting external displays.

Gestural interaction with freehands and while grasping an everyday object enables always-available input . To sense such gestures, minimal instrumentation of the user’s hand is desirable. However, the choice of an effective but minimal IMU layout remains challenging, due to the complexity of the multi-factorial space that comprises diverse finger gestures, objects, and grasps. We present SparseIMU , a rapid method for selecting minimal inertial sensor-based layouts for effective gesture recognition. Furthermore, we contribute a computational tool to guide designers with optimal sensor placement. Our approach builds on an extensive microgestures dataset that we collected with a dense network of 17 inertial measurement units (IMUs). We performed a series of analyses, including an evaluation of the entire combinatorial space for freehand and grasping microgestures (393 K layouts), and quantified the performance across different layout choices, revealing new gesture detection opportunities with IMUs. Finally, we demonstrate the versatility of our method with four scenarios.

Human hair opens up new opportunities for embodied interactions that build on its unique physical affordances and location on the body. As hair has high socio-cultural significance, the design of hair interfaces is coupled with social and personal needs. Albeit this makes field investigations indispensable, they are missing from prior work. We present a fabrication approach for gesture-controlled hair interfaces that are robust enough to be deployed in the field. Our approach contributes sensorized feather hair extensions that combine capacitive and piezoresistive sensing. Their tactile properties make the interface blend seamlessly with human hair. We furthermore contribute results from a field experiment where participants gained first-hand experience in various social contexts. These show how hair-based interactions have great potential moving beyond planar touch gestures whilst their social appropriateness is context-sensitive. We synthesize the findings into design implications that ground the future design of usable and socially acceptable hair interfaces.

We present Print-A-Sketch, an open-source handheld printer prototype for sketching circuits and sensors. Print-A-Sketch combines desirable properties from free-hand sketching and functional electronic printing. Manual human control of large strokes is augmented with computer control of fine detail. Shared control of Print-A-Sketch supports sketching interactive interfaces on everyday objects – including many objects with materials or sizes which otherwise are difficult to print on. We present an overview of challenges involved in such a system and show how these can be addressed using context-aware, dynamic printing. Continuous sensing ensures quality prints by adjusting inking-rate to hand movement and material properties. Continuous sensing also enables the print to adapt to previously printed traces to support incremental and iterative sketching. Results show good conductivity on many materials and high spatial precision, supporting on-the-fly creation of functional interfaces.

The last decade has witnessed an increase in Electrical Muscle Stimulation (EMS) research. Myriads of application scenarios have been proposed and toolkits, as well as procedures, have been presented to the research community. While these individual explorations provide a benefit to the research community, the overarching view on the topic is still unclear which helps to understand how such technology can be used in the future. To tackle this, we conduct a systematic literature survey of research utilizing EMS as a wearable output method. We investigate the published research (N = 151) by analyzing the EMS systems’ setup, calibration, and evaluation. We create a taxonomy of the application scenarios that categorize them along two dimensions (i.e., (1) action <> perception and (2) augmentation <> induction). Further, we distill open research challenges from our results that can help to stimulate and guide research on EMS in the future.

Designers and makers are increasingly interested in leveraging bio-based and bio-degradable ‘do-it-yourself’ (DIY) materials for sustainable prototyping. Their self-produced bioplastics possess compelling properties such as self-adhesion but have so far not been functionalized to create soft interactive devices, due to a lack of DIY techniques for the fabrication of functional electronic circuits and sensors. In this paper, we contribute a DIY approach for creating Interactive Bioplastics that is accessible to a wide audience, making use of easy-to-obtain bio-based raw materials and familiar tools. We present three types of conductive bioplastic materials and their formulation: sheets, pastes and foams. Our materials enable additive and subtractive fabrication of soft circuits and sensors. Furthermore, we demonstrate how these materials can substitute conventional prototyping materials, be combined with off-the-shelf electronics, and be fed into a sustainable material ‘life-cycle’ including disassembly, re-use, and re-melting of materials. A formal characterization of our conductors highlights that they are even on-par with commercially available carbon-based conductive pastes.

Proximal femur fractures represent a major health concern, and substantially contribute to the morbidity of elderly. Correct classification and diagnosis of hip fractures has a significant impact on mortality, costs and hospital stay. In this paper, we present a method and empirical validation for automatic subclassification of proximal femur fractures and Dutch radiological report generation that does not rely on manually curated data. The fracture classification model was trained on 11,000 X-ray images obtained from 5000 electronic health records in a general hospital. To generate the Dutch reports, we first trained an embedding model on 20,000 radiological reports of pelvic region fractures, and used its embeddings in the report generation model. We trained the report generation model on the 5000 radiological reports associated with the fracture cases. Our report generation model is on par with state-of-the-art in terms of BLEU and ROUGE scores. This is promising, because in contrast to those earlier works, our approach does not require manual preprocessing of either images or the reports. This boosts the applicability of automatic clinical report generation in practice. A quantitative and qualitative user study among medical students found no significant difference in provenance of real and generated reports. A qualitative, in-depth clinical relevance study with medical domain experts showed that from a human perspective the quality of the generated reports approximates the quality of the original reports and highlights challenges in creating sufficiently detailed and versatile training data for automatic radiology report generation.

Augmented Reality (AR) technology enables users to superpose virtual content onto their environments. However, interacting with virtual content while mobile often requires users to perform interactions in mid-air, resulting in a lack of haptic feedback. Hence, in this work, we present the ARm Haptics system, which is worn on the user's forearm and provides 3D-printed input modules, each representing well-known interaction components such as buttons, sliders, and rotary knobs. These modules can be changed quickly, thus allowing users to adapt them to their current use case. After an iterative development of our system, which involved a focus group with HCI researchers, we conducted a user study to compare the ARm Haptics system to hand-tracking-based interaction in mid-air (baseline). Our findings show that using our system results in significantly lower error rates for slider and rotary input. Moreover, use of the ARm Haptics system results in significantly higher pragmatic quality and lower effort, frustration, and physical demand. Following our findings, we discuss opportunities for haptics worn on the forearm.

We are surrounded by sensing devices. We are accustomed to them, appreciate their benefits, and even create affective bonds and might neglect the implications they might have for our daily life. By presenting Eyecam, an anthropomorphic webcam mimicking a human eye, we challenge conventional relationships with ubiquitous sensing devices and call to re-think how sensing devices might appear and behave. Inspired by critical design, Eyecam is an exaggeration of a familiar sensing device which allows for critical reflections on its perceived functionalities and its impact on human-human and human-device relations. We identify 5 different roles Eyecam can take: Mediator, Observer, Mirror, Presence, and Agent. Contributing design fictions and thinking prompts, we allow for articulation on privacy awareness and intrusion, affect in mediated communication, agency and self-perception along with speculation on potential futures. We envision this work to contribute to a bold and responsible design of ubiquitous sensing devices.

In traditional body-art, designs are adjusted to the body as they are applied, enabling creative improvisation and exploration. Conventional design and fabrication methods of epidermal interfaces, however, separate these steps. With BodyStylus we present the first computer-assisted approach for on-body design and fabrication of epidermal interfaces. Inspired by traditional techniques, we propose a hand-held tool that augments freehand inking with digital support: projected in-situ guidance assists creating valid on-body circuits and aesthetic ornaments that align with the human bodyscape, while pro-active switching between inking and non-inking creates error preventing constraints. We contribute BodyStylus’s design rationale and interaction concept along with an interactive prototype that uses self-sintering conductive ink. Results of two focus group explorations showed that guidance was more appreciated by artists, while constraints appeared more useful to engineers, and that working on the body inspired critical reflection on the relationship between bodyscape, interaction, and designs.

Many existing explorations of wearables for HCI consider functionality first and wearability second. Typically, as the technologies, designs, and experiential understandings develop, attention can shift towards questions of deployment and wearability. To support this shift of focus we present a case study of the iterative design of electrode sleeves. We consider the design motivations and background that led to the existing, prototype EMS sleeves, and the resultant challenges around their wearability. Through our own design research practice, we seek to reveal design criteria towards the wearability of such a sleeve, and provide designs that optimise for those criteria. We contribute (1) new electrode sleeve designs, which begin to make it practicable to take EMS beyond the lab, (2) new fabrication processes that support rapid production and personalisation, and (3) reflections on criteria for wearability across new eTextile garments.

With the increasing ubiquity of personal devices, social acceptability of human-machine interactions has gained relevance and growing interest from the HCI community. Yet, there are no best practices or established methods for evaluating social acceptability. Design strategies for increasing social acceptability have been described and employed, but so far not been holistically appraised and evaluated. We offer a systematic literature analysis (N=69) of social acceptability in HCI and contribute a better understanding of current research practices, namely, methods employed, measures and design strategies. Our review identified an unbalanced distribution of study approaches, shortcomings in employed measures, and a lack of interweaving between empirical and artifact-creating approaches. The latter causes a discrepancy between design recommendations based on user research, and design strategies employed in artifact creation. Our survey lays the groundwork for a more nuanced evaluation of social acceptability, the development of best practices, and a future research agenda.

Eyewear devices, such as augmented reality displays, increasingly integrate eye tracking, but the first-person camera required to map a user's gaze to the visual scene can pose a significant threat to user and bystander privacy. We present PrivacEye, a method to detect privacy-sensitive everyday situations and automatically enable and disable the eye tracker's first-person camera using a mechanical shutter. To close the shutter in privacy-sensitive situations, the method uses a deep representation of the first-person video combined with rich features that encode users' eye movements. To open the shutter without visual input, PrivacEye detects changes in users' eye movements alone to gauge changes in the "privacy level" of the current situation. We evaluate our method on a first-person video dataset recorded in daily life situations of 17 participants, annotated by themselves for privacy sensitivity, and show that our method is effective in preserving privacy in this challenging setting.

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.

Innovations often trigger objections before becoming widely accepted. This paper assesses whether a familiarisation over time can be expected for data glasses, too. While user attitudes towards those devices have been reported to be prevalently negative [14], it is still unclear, to what extent this initial, negative user attitude might impede adoption. However, indepth understanding is crucial for reducing barriers early in order to gain access to potential benefits from the technology. With this paper we contribute to a better understanding of factors affecting data glasses adoption, as well as current trends and opinions. Our multiple-year case study (N=118) shows, against expectations, no significant change towards a more positive attitude between 2014 and 2016. We complement these findings with an expert survey (N=51) investigating prognoses, challenges and discussing the relevance of social acceptability. We elicit and contrast a controversial spectrum of expert opinions, and assess whether initial objections can be overwritten. Our analysis shows that while social acceptability is considered relevant for the time being, utility and usability are more valued for long-term adoption.

Though still a rare sight, body-worn lifelogging cameras such as Mofily's YoCam or the Narrative Clip have become increasingly popular amongst tech-savvy audiences. In this paper, we investigate whether users of those devices prefer to wear them openly or in a concealed, less obtrusive manner. We discuss the camouflage of lifelogging cameras based on results from an online study (N=117), including the why (not) and how as well as qualitative insights on how social contexts influence usage habits. The results of our study provide empirical evidence that deliberate concealment can be perceived unethical, and that moderate noticeability is favoured. We furthermore found contrary effects of lifelogging cameras in interpersonal relationships, including self-censorship by the user, avoidance behaviour by her/his peers and conversation starting character of the device itself. We conclude by highlighting design challenges concerning ubiquitous, body-worn cameras.

Computational thinking has received increased attention over the past several years and is considered by many to be a fundamental and necessary literacy for children. One approach to teaching this skill has been through tangible programming since it facilitates intuitive interaction with children. In this paper, we introduce CodeTrain and CodeBox, two motorized toys whose behavior can be programmed through wooden building blocks without the use of a computer, tablet, or screen-based interface. The goal with both these designs is to foster playful exploration of computational thinking in pre-adolescent children through tangible objects. We describe the design process from the conceptual design to the functional prototype. Furthermore, we present first impressions of the prototypes from a pilot study and highlight some lessons learned from our first iteration.

We present a machine learning technique to recognize gestures and estimate metric depth of hands for 3D interaction, relying only on monocular RGB video input. We aim to enable spatial interaction with small, body-worn devices where rich 3D input is desired but the usage of conventional depth sensors is prohibitive due to their power consumption and size. We propose a hybrid classification-regression approach to learn and predict a mapping of RGB colors to absolute, metric depth in real time. We also classify distinct hand gestures, allowing for a variety of 3D interactions. We demonstrate our technique with three mobile interaction scenarios and evaluate the method quantitatively and qualitatively.

Data glasses do carry promising potential for hands-free interaction, but also raise various concerns amongst their potential users. In order to gain insights into the nature of those concerns, we investigate how potential usage scenarios are perceived by device users and their peers. We present results of a two-step approach: a focus group discussion with 7 participants, and a user study with 38 participants. In particular, we look into differences between the usage of data glasses and more established devices such as smart phones. We provide quantitative measures for scenario-related social acceptability and point out factors that can influence user attitudes. Based on our quantitative and qualitative results, we derive design implications that might support the development of head-worn devices and applications with an improved social acceptability.

Immersive AR environments are situated information spaces that employ the Augmented Reality display paradigm. They tightly couple abstract, digital information and physical elements present in the user's real-world environment. As a consequence of this mixed digital-physical spatiality, interface design has the chance to build upon the user's cognitive map (spatial mental model) of her environment. The proposed PhD project investigates how knowledge about a user's spatial mental model of an augmented scene can be translated to best practices in the design of remotely shared AR environments.

Mobile location recognition by capturing images of the environment (visual localization) is a promising technique for indoor navigation in arbitrary surroundings. However, it has barely been investigated so far how the user interface (UI) can cope with the challenges of the vision-based localization technique, such as varying quality of the query images. We implemented a novel UI for visual localization, consisting of Virtual Reality (VR) and Augmented Reality (AR) views that actively communicate and ensure localization accuracy. If necessary, the system encourages the user to point the smartphone at distinctive regions to improve localization quality. We evaluated the UI in a experimental navigation task with a prototype, informed by initial evaluation results using design mockups. We found that VR can contribute to efficient and effective indoor navigation even at unreliable location and orientation accuracy. We discuss identified challenges and share lessons learned as recommendations for future work.

The ongoing evolution of mobile phones to "pocket computers" generated a demand for more and more applications to be ported to the mobile phone. Because a full security assessment for a whole mobile operating system would be prohibitively costly, currently security critical applications can not be implemented. We address this challenge by introducing security zones to enable applications with high security demands like driving licenses, health insurance cards, or passports on mobile phones. This zone concept creates the need for visualization of the current zone and a way to switch between zones. In this paper we discuss several possible ways of achieving this.

We consider the reasons why we organise books in a physical environment and investigate whether situating interactions with a smartphone could improve the user experience of e-readers. Our prototype uses the Kinect depth sensor to detect the position of a user in relation to sections of a physical bookshelf. We also built a mobile application that allows users to browse and organise digital books by moving between each section. We present our initial observations of a user study that evaluated search and categorisation tasks with our prototype. Our findings motivate reasons to explore digital books in a physical environment and indicate issues to consider when designing situated interactions with e-readers.

User authentication on publicly exposed terminals with established mechanisms, such as typing the credentials on a virtual keyboard, can be insecure e.g. due to shoulder surfing or due to a hacked terminal. In addition, username and password entry can be time-consuming and thus improvable with relation to usability. As security and comfort are often competing with each other, novel authentication and authorization methods especially for public terminals are desirable. In this paper, we present an approach on a distributed authentication and authorization system, where the user can be easily identified and enabled to use a service with his smartphone. The smartphone (as personal and private device the user is always in control of) can provide a highly secure authentication token that is renewed and exchanged in the background without the user's participation. The claimed improvements were supported by a user survey with an implementation of a digital room management system as an example for a public display. The proposed authentication procedure would increase security and yet enable fast authentication within publicly exposed terminals.

Saving money is usually a tedious task that requires a high degree of self-control for many of us. Some people have one or more specific savings targets in mind and thus need to prioritize them. We propose connecting a savings box with a personal smartphone. Thus, people become motivated to keep track of their savings for multiple targets. Using a savings box capable of counting money and connecting it to an app, we believe people stick to their plans to save with higher motivation and are happier with their behavior. In this paper, we present first evidence for the success of this concept. We gathered feedback through an online user study in which participants were shown a video prototype. We propose further research directions with our SmartPiggy, to confirm the feasibility of behavioral economics in HCI.