The growing use of AI in public administration improves efficiency, yet its use in discretionary decisions raises concerns about fairness and legitimacy. While prior research examined decision stakes and Human–AI decision-making configurations separately, their combined effect on citizens’ perceptions of fairness and adoption remains underexplored. We conducted a mixed-method Wizard-of-Oz study (n=43) using an Intelligent-Self-Service-Kiosk. Participants completed a low-stakes (ID-renewal) and a high-stakes (social-housing) task under one of three decision-making configurations: AI alone, AI with human-supervision, and human with AI advice or recommendation. Quantitative analysis found no significant effects, highlighting the limits of standard metrics. However, qualitative interviews revealed that citizens valued human involvement, requiring meaningful over symbolic oversight. They emphasized interactive dialogue before decisions to capture their circumstances and after, to facilitate appeals. We contribute evidence of tensions between citizens’ desire for efficiency and need for human-control and fairness. We provide guidance for designing citizen-centered AI systems that align with democratic values.

In face-to-face interactions, people rely on facial expressions, body posture, and further verbal and non-verbal cues to infer others’ internal states. While collaborative virtual reality (VR) enables rich shared experiences, it offers fewer expressive cues, making perceiving mental states like attention, intention, or cognitive load (CL) more difficult. Rather than replicating real-world cues, we investigated how augmenting collaborative VR with real-time visualizations of users’ CL impacts social presence. We first conducted semi-structured interviews (N = 6) and an online survey (N = 54) to elicit user needs and design preferences for CL visualizations. These insights informed the development of a collaborative VR application evaluated in a lab experiment (N = 30). Participants engaged in verbal explanation tasks of varying difficulty while their CL was displayed using different visualizations (pie charts, bar charts, brain diagrams), including a no-visualization control condition. Social presence was measured using the Networked Minds Social Presence Inventory and augmented via post-experiment interviews. Our results show that in difficult tasks, pie chart visualizations helped sustain co-presence, while all diagrams supported affective understanding. These findings demonstrate the potential of intuitive CL visualizations to foster social connectedness, helping inform future designs of collaborative VR.

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.

In this paper, banking services, as the research object to explore the relationship among distributive fairness, procedural fairness, interactive fairness and informational fairness. The study found: informational fairness significant impact on the ...

Professional and personal lives are undergoing a shift from physical to virtual meetings. While this offers numerous advantages, such as increased spatial autonomy, it also poses risks to the social bonds among employees, families, and friends. Even current collaborative virtual reality (VR) applications cannot bridge the separation in virtual meetings, as they do not provide a sense of social connectedness comparable to in-person interaction. Reasons include limited behavioral realism of VR avatars, e.g., in displayed body movements. We systematically investigated how realistic body movements influence Social Presence in a collaborative VR task. We explored three types of motion-tracking mechanisms: no motion-tracking beyond controllers, hand-tracking, and full-body motion-tracking with hand-tracking. To examine their influence on Social Presence, we designed a spatial collaboration task based on insights gained from semi-structured interviews ( N = 6). Subsequently, we conducted a controlled VR experiment ( N = 18), in which participants' counterparts employed the various motion-tracking technologies while performing said task. Our results demonstrate that realistic body movements do not influence self-reported Social Presence in VR. Nevertheless, they entail an increased interpersonal distance among users, attributable to a subconscious influence on Social Presence.

As the world becomes more interconnected, physical separation between people increases. Existing collaborative Virtual Reality (VR) applications, designed to bridge this distance, are not yet sufficient in providing a sense of social connection comparable to face-to-face interactions. Possible reasons are the limited multimodality of VR systems and the lack of non-verbal cues in VR avatars. We systematically investigated how facial expressions influence Social Presence in two collaborative VR tasks. We explored four types of facial expressions: eyes and mouth movements, their combination, and no expressions, for two types of explanations: verbal and graphical. To examine how these expressions influence Social Presence, we conducted a controlled VR experiment (N = 48), in which participants had to explain a specific term to their counterpart. Our results demonstrate that eye and mouth movements positively influence Social Presence in VR. Particularly, combining verbal explanations and eye movements induces the highest feeling of co-presence.

Intensive care nurses are prone to suffering from chronic stress due to constant exposure to two main profession-related stressors: interruption and time pressure. These stressors have detrimental effects on the well-being of the nursing staff and, by proxy, the patients. To alleviate stress, increase safety, and support the training of stressful scenarios, we investigate the impact these stressors have on subjective and objective stress levels in a virtual environment. We designed an intensive care unit in which participants (n=26, 18 healthcare professionals) perform common tasks, e.g. refilling an infusion pump, whilst being exposed to interruptions and time pressure. Results from our between-subjects study provide data indicating stress increase in both stressor conditions, suggesting that artificially evoking work-related stressors for stress inoculation training (SIT) is a possible extension to simulation training during nursing education. This knowledge is helpful for designing training scenarios of safety-critical situations early in the professional apprenticeship.

Nurses in intensive care units are exposed to permanent stress. Emotional stress contributes to psycho-physiological exhaustion symptoms such as chronic sleep disturbances, restlessness or burnout, which negatively affects the quality of care and interaction with patients. A promising method for learning coping strategies to deal with stress is Stress Inoculation Training, which involves practicing stressors in a controlled environment at increasing intensity. In this work, using virtual reality, the stressor of having to comply with the patient’s or family’s wishes, even if one does not agree with them, was selected. The stressor was defined based on a literature review and interviews with experts which was then implemented in three intensity levels. In a Wizard-of-Oz trial, participants interacted with virtual characters using natural speech. The stress response of the induced stress was measured using objective (heart rate, time between R peaks, skin conductance, and respiratory rate) and subjective measures (Perceived Stress Questionnaire and a 7-point Likert item). While objective results do not show significant differences between intensity levels, a significant increase is detected in the subjective measures. We show that emotional stress can be induced by increasing the intensity of a stressor in VR using virtual characters.

German Intensive Care Units (ICUs) are in crisis, struggling with an increasing shortage of skilled workers, ultimately putting patients’ safety at risk. To counteract this process, researchers are increasingly concerned with finding digital solutions which aim to support healthcare professionals by enhancing the efficiency of reoccurring critical caring tasks and thus, improve working conditions. In this regard, this paper evaluates the application of Augmented Reality (AR) for patient monitoring for critical care nursing. Grounded on an observational study, semi-structured interviews, as well as a quantitative analysis, mobile patient monitoring scenarios, present particularly during patient transport, were identified as an innovative context of use of AR in the field. Additionally, user requirements such as high wearability, hands-free operability, and clear data representation could be derived from the obtained study results. For validation of these and identification of further requirements, three prototypes differing in their data illustration format were subsequently developed and quantitatively, as well as qualitatively evaluated by conducting an online survey. Thereby, it became evident that future implementations of a corresponding system for patient monitoring ought to integrate a context-dependent data presentation in particular, as this combines high navigability and availability of required data. Identifying patient monitoring during patient transport as a potential context of use, as well as distinguishing a context-dependent design approach as favorable constitute two key contributions of this work and provide a foundation on which future implementations of AR systems in the nursing domain and other related contexts can be established.

Safety critical situations, as they occur in professions such as medicine, nursing, and aviation, are often trained in simulators to prevent damages to personnel and material. These jobs often come with a high amount of stress, to which prolonged exposure can have devastating effects. Over the past years, stress inoculation training in conjunction with Virtual Reality has become focus of the research community and software companies. Especially the nursing profession can benefit from it, since stress-related illnesses are often the reason for an early exit from the workforce. However, since training facilities often need to compromise on their simulations due to monetary reasons, trade-offs must be made in the degree of detail of such simulations in order to keep development and acquisition costs low. One such possibility is in using low graphical fidelity. We present a psycho-physiological study on the influence of image realism of virtual environments on the stress response. In a within subject design study, we ask participants to complete nursing related, virtually recreated tasks in an artificial intensive care unit, whilst exposed to different stress factors. We provide our findings in the form of objective and subjective measures. Results show that one can elicit different stress responses by manipulating image realism in a sufficiently drastic manner. However, a life-like reaction does not seem to depend on a highly realistic environment.

Manual assembly tasks require workers to precisely assemble parts in 3D space. Often additional time pressure increases the complexity of these tasks even further (e.g., adhesive bonding processes). Therefore, we investigate how Augmented Reality (AR) can improve workers’ performance in time and spatial dependent process steps. In a user study, we compare three conditions: instructions presented on (a) paper, (b) a camera-based see-through tablet, and (c) a head-mounted AR device. For instructions we used selected work steps from a standardized adhesive bonding process as a representative for common time-critical assembly tasks. We found that instructions in AR can improve the performance and understanding of time and spatial factors. The tablet instruction condition showed the best subjective results among the participants, which can increase motivation, particularly among less-experienced workers.

For nurses, analyzing a patient’s room upon entry is crucial because health history and current status are essential for decision making in case of emergency. In order to understand a nurses perception of the situation and the environment, researchers have turned to Virtual Reality (VR). Eye tracking can be used to understand how users perceive virtual environments and can contribute to a deeper understanding of users’ cognitive processes.

The fast pace of market development of medical devices combined with a slow adoption rate in health care often results in unawareness about technology that can aid the nursing process. Often, knowledge about the availability of such helpers only arises when the employer implements such a system. In that case, employees are ill-prepared and overwhelmed by the sudden change in their routine or are surprised that the device in question has not been adopted earlier. To alleviate that situation, research institutes maintain real labs that can be toured by the public, getting an early look on technology or learn about products that are readily available on the market. Using virtual reality, we go one step further to improve the reach and further decrease the cost of maintaining such labs in order to educate nursing professionals on state-of-the-art products.

Navigation systems for cyclists are commonly screen-based devices mounted on the handlebar which show map information. Typically, adult cyclists have to explicitly look down for directions. This can be distracting and challenging for children, given their developmental differences in motor and perceptual-motor abilities compared with adults. To address this issue, we designed different unimodal cues and explored their suitability for child cyclists through two experiments. In the first experiment, we developed an indoor bicycle simulator and compared auditory, light, and vibrotactile navigation cues. In the second experiment, we investigated these navigation cues in-situ in an outdoor practice test track using a mid-size tricycle. To simulate road distractions, children were given an additional auditory task in both experiments. We found that auditory navigational cues were the most understandable and the least prone to navigation errors. However, light and vibrotactile cues might be useful for educating younger child cyclists.

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.

Locating objects in physical environments can be an exhausting and frustrating task, particularly when these objects are out of the user's view or occluded by other objects. With recent advances in Augmented Reality (AR), these environments can be augmented to visualize objects for which the user searches. However, it is currently unclear which visualization strategy can best support users in locating these objects. In this paper, we compare a printed map to three different AR visualization strategies: (1) in-view visualization, (2) out-of-view visualization, and (3) the combination of in-view and out-of-view visualizations. Our results show that in-view visualization reduces error rates for object selection accuracy, while additional out-of-view object visualization improves users' search time performance. However, combining in-view and out-of-view visualizations leads to visual clutter, which distracts users.

Child cyclists are at greater risk for car-to-cyclist accidents than adults. This is in part due to developmental differences in the motor and perceptual-motor abilities of children and adults, and missing cycling infrastructure. To address these issues, we examine unimodal and projection-based techniques to support children in maintaining a good lane position in the absence of bicycle lanes. We present safety-relevant information using unimodal cues: vibration on the handlebar, ambient light in a cycle helmet, projected heads-up display indicators, and on-road laser projection. As a first step, we interviewed twelve children about their cycling issues. We then conducted a lab experiment (N=25) in a bicycle simulator using the unimodal cues in the presence of a visual search task, followed by a controlled test-track experiment (N=15). We found that cycling performance with lane keeping cues was comparable to situations without them, however children found them helpful and expressed subjective preferences for the LED helmet and vibration on the handlebar.

Current head-mounted displays (HMDs) have a limited field-of-view (FOV). A limited FOV further decreases the already restricted human visual range and amplifies the problem of objects receding from view (e.g., opponents in computer games). However, there is no previous work that investigates how to best perceive moving out-of-view objects on head-mounted displays. In this paper, we compare two visualization approaches: (1) Overview+detail, with 3D Radar, and (2) Focus+context, with EyeSee360, in a user study to evaluate their performances for visualizing moving out-of-view objects. We found that using 3D Radar resulted in a significantly lower movement estimation error and higher usability, measured by the system usability scale. 3D Radar was also preferred by 13 out of 15 participants for visualization of moving out-of-view objects.

Knowing the locations of spatially distributed objects is important in many different scenarios (e.g., driving a car and being aware of other road users). In particular, it is critical for preventing accidents with objects that come too close (e.g., cyclists or pedestrians). In this paper, we explore how peripheral cues can shift a user's attention towards spatially distributed out-of-view objects. We identify a suitable technique for visualization of these out-of-view objects and explore different cue designs to advance this technique to shift the user's attention. In a controlled lab study, we investigate non-animated peripheral cues with audio stimuli and animated peripheral cues without audio stimuli. Further, we looked into how user's identify out-of-view objects. Our results show that shifting the user's attention only takes about 0.86 seconds on average when animated stimuli are used, while shifting the attention with non-animated stimuli takes an average of 1.10 seconds.

This paper investigates bias in coverage between Western and Arab media on Twitter after the November 2015 Beirut and Paris terror attacks. Using two Twitter datasets covering each attack, we investigate how Western and Arab media differed in coverage bias, sympathy bias, and resulting information propagation. We crowdsourced sympathy and sentiment labels for 2,390 tweets across four languages (English, Arabic, French, German), built a regression model to characterize sympathy, and thereafter trained a deep convolutional neural network to predict sympathy. Key findings show: (a) both events were disproportionately covered (b) Western media exhibited less sympathy, where each media coverage was more sympathetic towards the country affected in their respective region (c) Sympathy predictions supported ground truth analysis that Western media was less sympathetic than Arab media (d) Sympathetic tweets do not spread any further. We discuss our results in light of global news flow, Twitter affordances, and public perception impact.

Take-over requests (TORs) in highly automated vehicles are cues that prompt users to resume control. TORs however, are often evaluated in non-moving driving simulators. This ignores the role of motion, an important source of information for users who have their eyes off the road while engaged in non-driving related tasks. We ran a user study in a moving-base driving simulator to investigate the effect of motion on TOR responses. We found that with motion, user responses to TORs vary depending on the road context where TORs are issued. While previous work showed that participants are fast to respond to urgent cues, we show that this is true only when TORs are presented on straight roads. Urgent cues issued on curved roads elicit slower responses than non-urgent cues on curved roads. Our findings indicate that TORs should be designed to be aware of road context to accommodate natural user responses.

Grandparents and grandchildren that live apart often rely on communication technologies, such as messengers, video conferencing, and phone calls for maintaining relationships. While some of these systems are challenging for grandparents, others are less engaging for children. To facilitate communication, we developed StoryBox, a tangible device that allows sharing photos, tangible artifacts, and audio recordings of everyday life. We conducted a preliminary study with two families to identify design issues, and further refine the prototype. Subsequently, we conducted a field study with four families for up to four weeks to better understand real-world use and examine inter-generational connectedness. We found that StoryBox was accessible, simple, and helped bridge the technological gap between grandparents and grandchildren. Children communicated asynchronously in a playful and idiosyncratic manner, and grandparents shared past family memories. We provide insights on how to ease communication between different generations, engage them in sharing activities, and strengthen family relationships.

Although the mobility and emerging technology of augmented reality (AR) have brought significant entertainment and convenience in everyday life, the use of AR is becoming a social problem as the accidents caused by a shortage of situation awareness due to an immersion of AR are increasing. In this paper, we address the trade-off between immersion and situation awareness as the fundamental factor of the AR-related accidents. As a solution against the trade-off, we propose a third-party component that prevents pedestrian-vehicle accidents in a traffic environment based on vehicle position estimation (VPE) and vehicle position visualization (VPV). From a RGB image sequence, VPE efficiently estimates the relative 3D position between a user and a car using generated convolutional neural network (CNN) model with a region-of-interest based scheme. VPV shows the estimated car position as a dot using an out-of-view object visualization method to alert the user from possible collisions. The VPE experiment with 16 combinations of parameters showed that the InceptionV3 model, fine-tuned on activated images yields the best performance with a root mean squared error of 0.34 m in 2.1 ms. The user study of VPV showed the inversely proportional relationship between the immersion controlled by the difficulty of the AR game and the frequency of situation awareness in both quantitatively and qualitatively. Additional VPV experiment assessing two out-of-view object visualization methods (EyeSee360 and Radar) showed no significant effect on the participants' activity, while EyeSee360 yielded faster responses and Radar engendered participants' preference on average. Our field study demonstrated an integration of VPE and VPV which has potentials for safety-ensured immersion when the proposed component is used for AR in daily uses. We expect that when the proposed component is developed enough to be used in real world, it will contribute to the safety-ensured AR, as well as to the population of AR.

Highly automated vehicles, occasionally require users to resume vehicle control from non-driving related tasks by issuing cues called take-over request (TOR). Due to being engaged in non-driving related tasks (NDRT), users have a decreased level of situational awareness of the driving context. Therefore, user interface designs for TORs should ensure smooth transitions from the NDRTs to vehicle control. In this paper, we investigated the role of decision priming cues as TORs across different levels of NDRT engagement. In a driving simulator, users performed a reading span task while driving in automated mode. They received audio-visual TORs which primed them with an appropriate maneuver (steering vs. braking), depending on the traffic situation. Our results showed that priming users with upcoming maneuvers results in faster responses and longer time to collision to obstacles. However, the level of engagement in NDRT does not affect user responses to TORs.

Head-mounted devices (HMDs) for Virtual and Augmented Reality (VR/AR) enable us to alter our visual perception of the world. However, current devices suffer from a limited field of view (FOV), which becomes problematic when users need to locate out of view objects (e.g., locating points-of-interest during sightseeing). To address this, we developed and evaluated in two studies HaloVR, WedgeVR, HaloAR and WedgeAR, which are inspired by usable 2D off-screen object visualization techniques (Halo, Wedge). While our techniques resulted in overall high usability, we found the choice of AR or VR impacts mean search time (VR: 2.25s, AR: 3.92s) and mean direction estimation error (VR: 21.85°, AR: 32.91°). Moreover, while adding more out-of-view objects significantly affects search time across VR and AR, direction estimation performance remains unaffected. We provide implications and discuss the challenges of designing for VR and AR HMDs.

Current head-mounted displays (HMDs) for Virtual Reality (VR) and Augmented Reality (AR) have a limited field-of-view (FOV). This limited FOV further decreases the already restricted human visual range and amplifies the problem of objects going out of view. Therefore, we explore the utility of augmenting HMDs with RadialLight, a peripheral light display implemented as 18 radially positioned LEDs around each eye to cue direction towards out-of-view objects. We first investigated direction estimation accuracy of multi-colored cues presented on one versus two eyes. We then evaluated direction estimation accuracy and search time performance for locating out-of-view objects in two representative 360° video VR scenarios. Key findings show that participants could not distinguish between LED cues presented to one or both eyes simultaneously, participants estimated LED cue direction within a maximum 11.8° average deviation, and out-of-view objects in less distracting scenarios were selected faster. Furthermore, we provide implications for building peripheral HMDs.

Child cyclists are often at greater risk for traffic accidents. This is in part due to the development of children's motor and perceptual-motor abilities. To facilitate road safety for children, we explore the use of multimodal warning signals to increase their awareness and prime action in critical situations. We developed a bicycle simulator instrumented with these signals and conducted two controlled experiments. We found that participants spent significantly more time perceiving visual than auditory or vibrotactile cues. Unimodal signals were the easiest to recognize and suitable for encoding directional cues. However, when priming stop actions, reaction time was shorter when all three modalities were used simultaneously. We discuss the implications of these outcomes with regard to design of safety systems for children and their perceptual-motor learning.

While performing multiple competing tasks at the same time, e.g., when driving, assistant systems can be used to create cues to direct attention towards required information. However, poorly designed cues will interrupt or annoy users and affect their performance. Therefore, we aim to identify cues that are not missed and trigger a quick reaction without changing the primary task performance. We conducted a dual-task experiment in an anechoic chamber with LED-based stimuli that faded in or turned on abruptly and were placed in the periphery or front of a subject. Additionally, a white noise sound was triggered in a third of the trials. The primary task was to react to visual stimuli placed on a screen in front. We observed significant effects on the response times in the screen task when adding sound. Further, participants responded faster to LED stimuli when they faded in.

Automation shortcomings in highly automated driving (level 3) might require the driver to take over vehicle control. When the vehicle issues a take-over request (TOR), the driver has to immediately comprehend the situation, which highly demands visual attention. Therefore, haptic channel has the potential to be used for conveying information about driving context at take-over to assist decision making. In this work, we introduce the concept and prototype design of a shape-changing steering wheel which conveys contextual information at take-over. We evaluated this concept in comparison with an identical wheel with vibration cues. Results showed that haptic cues on steering wheel at TOR reassure drivers of their decisions rather than assisting them in decision making, and overall workload ratings are decreased using vibration cues. To assist decision making, contextual haptic cues in level 3 should be located on-body or on drivers' seat.

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.

Activity trackers are frequently used in health and well-being, but their application in effective interventions is challenging. While research for reasons of use and non-use is ongoing, little is known about the way activity trackers are used in everyday life and over longer periods. We analyzed data of 104 individuals over 14,413 use days, and in total over 2.5 years. We describe general tracker use, periodic changes and overall changes over time, and identify characteristic patterns. While the use of trackers shows large individual heterogeneity, from our findings we could identify and classify general patterns for activity tracker use such as try-and-drop, slow-starter, experimenter, hop-on hop-off, intermittent and power user. Our findings contribute to the body of knowledge towards the successful design of effective health technologies, health interventions, and long-term health applications.

Various off-screen visualization techniques that point to off-screen objects have been developed for small screen devices. A similar problem arises with head-mounted Augmented Reality (AR) with respect to the human field-of-view, where objects may be out of view. Being able to detect so-called out-of-view objects is useful for certain scenarios (e.g., situation monitoring during ship docking). To augment existing AR with this capability, we adapted and tested well-known 2D off-screen object visualization techniques (Arrow, Halo, Wedge) for head-mounted AR. We found that Halo resulted in the lowest error for direction estimation while Wedge was subjectively perceived as best. We discuss future directions of how to best visualize out-of-view objects in head-mounted AR.

Nowadays, Mixed and Virtual Reality devices suffer from a field of view that is too small compared to human visual perception. Although a larger field of view is useful (e.g., conveying peripheral information or improving situation awareness), technical limitations prevent the extension of the field-of-view. A way to overcome these limitations is to extend the field-of-view with peripheral light displays. However, there are no tools to support the design of peripheral light displays for Mixed or Virtual Reality devices. Therefore, we present our prototyping tool PeriMR that allows researchers to develop new peripheral head-mounted light displays for Mixed and Virtual Reality.

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.

Most of today's wearable devices mainly focus on functionality and show large deficits in aesthetics and comfort. However, researchers and market analysts emphasise the importance of aesthetics for wearable technology to be successful. Smart Digital Jewellery has been proposed as an approach to seamlessly integrate technology into appealing, body-worn objects. In this work, we investigated how a smart digital multi-purpose bracelet should be designed in order to be attractive, functional, easily comprehensible, and easy to manage. We built the Tangible Apps Bracelet and evaluated it in a lab study. The Tangible Apps Bracelet integrates multiple applications in form of single elements that are threaded on a string. Participants experienced it very positively, easy to interact with, and rated its usability and user experience as very good. They particularly appreciated its simple interaction and display concept and the seamless integration of applications and digital components into an aesthetic piece of jewellery.

Time is a complex concept that takes children years to learn. Yet, many of their activities are bounded by time constraints. We aim to support children in learning time with intuitive interaction with a prototype presenting time periods unobtrusively. We present Timelight, an ambient light display designed to help children better understand the duration of time periods. We derive requirements from interviews and a focus groups with teachers, parents and HCI experts. We establish an interaction design and develop a prototype for a field exploration study. We explore the functionality of and interaction with Timelight in families, kindergarten groups and school classes in a two-week field study. Our results show that ambient light is well suited to keep children updated on the duration of time in various contexts of their daily life. Our participants use Timelight on a vast range of occasions and identify additional roles for the display.

Take-over situations in highly automated driving occur when drivers have to take over vehicle control due to automation shortcomings. Due to high visual processing demand of the driving task and time limitation of a take-over maneuver, appropriate user interface designs for take-over requests (TOR) are needed. In this paper, we propose applying ambient TORs, which address the peripheral vision of a driver. Conducting an experiment in a driving simulator, we tested a) ambient displays as TORs, b) whether contextual information could be conveyed through ambient TORs, and c) if the presentation pattern (static, moving) of the contextual TORs has an effect on take-over behavior. Results showed that conveying contextual information through ambient displays led to shorter reaction times and longer times to collision without increasing the workload. The presentation pattern however, did not have an effect on take-over performance.

Truck platooning has advantages for fuel consumption, road safety, and use of the existing road infrastructure. However, it does not simplify the job of truck drivers who reportedly fear driving in close distance and mistrust the automation. Prior work indicates that a platooning assistant system can help overcoming these issues. However, there are no practical experiences with on-the-road platooning that shed light on how drivers perceive and evaluate such a system. In this work, we close this gap and present PlatoonPal, a platooning assistance system which we rigorously developed in a user centered way. We further present the results of a field test with three platooning trucks where drivers used PlatoonPal under real conditions. The results show that drivers are positive using the system and preferred information related closely to the current situation. We conclude the paper with guidelines for the future development of assistance systems for platooning.

In the last decade, several in-vehicle light displays have been proposed. These displays inform drivers via light patterns that go beyond simple status indicators. In this literature survey, we present 21 works with their light displays and patterns. In addition, we summarize the common methods and results of these works. This work will help researchers and designers find a good starting point for looking into in-vehicle light displays. It may further foster discussions about best practices in the community.

While HCI for development (HCI4D) research has typically focused on technological practices of poor and low-literate communities, little research has addressed how technology literate individuals living in a poor infrastructure environment use technology. Our work fills this gap by focusing on Lebanon, a country with longstanding political instability, and the wayfinding issues there stemming from missing street signs and names, a poor road infrastructure, and a non-standardized addressing system. We examine the relationship between technology literate individuals' navigation and direction giving strategies and their usage of current digital navigation aids. Drawing on an interview study (N=12) and a web survey (N=85), our findings show that while these individuals rely on mapping services and WhatsApp's share location feature to aid wayfinding, many technical and cultural problems persist that are currently resolved through social querying. We discuss our results in light of problems that any map user encounters in poor infrastructure environments.

Car navigation systems typically combine multiple output modalities; for example, GPS-based navigation aids show a real-time map, or feature spoken prompts indicating upcoming maneuvers. However, the drawback of graphical navigation displays is that drivers have to explicitly glance at them, which can distract from a situation on the road. To decrease driver distraction while driving with a navigation system, we explore the use of ambient light as a navigation aid in the car, in order to shift navigation aids to the periphery of human attention. We investigated this by conducting studies in a driving simulator, where we found that drivers spent significantly less time glancing at the ambient light navigation aid than on a GUI navigation display. Moreover, ambient light-based navigation was perceived to be easy to use and understand, and preferred over traditional GUI navigation displays. We discuss the implications of these outcomes on automotive personal navigation devices.

The exchange of daily moods is an important part of interpersonal communication over a distance. Mobile devices offer a platform for sharing on the go, and keeping in touch regularly. However, it is still a challenge to design an input for mood, such that the sharing easily integrates into the daily life and is engaging for a longer time. To design an input, which overcomes these challenges, we explore the use of four different methods for expressing mood on mobile devices, drawn from previous work in psychology. We aim to verify the usefulness of these methods and want to investigate this by conducting a comparative study of these four input methods, regarding the following factors: intuitiveness, inconvenience, speed of input, everyday use, expressiveness and overall suitability. Results show that use of photographs and emotion terms are suitable to describe the many facets of moods for most participants. Most of the participants prefer personalized input methods as well as combined methods. We discuss the outcomes with regard to the implications on future designs of messenger applications.

The number of assistance systems in cars has been increasing in recent years. While these systems are targeted at supporting the individual driver and his or her safety, they may though compete for the driver's attention, and may demand too much of the driver's cognitive resources. Based on the established multiple resource theory in recent years, the use of different multimodal displays has been investigated that give the driver attention while not overloading sensory channels. In our work, we are looking into peripheral light displays in means to present safety relevant information. In this paper, we present the results of an experiment in which a peripheral light display was used to show the distance to a closing vehicle. The display is an LED stripe, seamlessly integrated into the side door and the dashboard of the car. Two different light patterns were tested in an overtaking scenario in a driving simulator. One pattern encodes the expected time to collision to the left rear car by moving a light source towards the front left corner. The other pattern additionally adapts its brightness to a simplified model of the driver's certainty to get his or her attention in uncertain situations. In contrast to previous works, we did not focus on a warning system but on a decision aid system. We found that using the adaptive pattern led to faster decisions and therefore to a smaller probability of violating safety distances. We believe that this pattern is a good basis for patterns which are fine-tuned to individual drivers as well as better driver models.

In the recent years, several automotive manufacturers started to integrate ambient light displays into cars to increase drivers' comfort. Expanding their possible application areas, we propose a display that continuously informs the driver of the vehicle's as well as the environment's state. We studied this display in a lane change maneuver, in which a driver has to decide if he or she can change lane in front of a faster closing car or brake to keep a safe distance to a slower car in front. We present results of an experiment for light patterns that are based on results of a design workshop and definitions for lane change decision aid systems (LCDAS) of ISO 17387. Though we used ISO's definitions for the timings, our participants felt that status updates on the display came too late. In addition, the abrupt warnings, implemented in one of the tested patterns, led to worse performance of the participants. On the other hand, we observed that participants liked a continuous encoding of the time-to-collision (TTC) and observed a decrease in missed opportunities to overtake. Therefore, we argue that the defined limits for the warning levels are not well suited to support drivers during decision making in our scenario. Our contribution lies in a novel way of supporting drivers during lane change using an ambient in-vehicle light display. We showed that a continuous light pattern might help drivers in decision making, while more research has to be done to validate this.

Recent interest in the development of ambient light systems has initialized a new research area, where the number of ambient light systems is expected to increase in the next years. To support the development of future ambient light systems, we need clear, explicit, and structured design guidelines. In this paper we present an evaluation of light patterns in a controlled laboratory study with two complementary parts. In the first part, our aim was to reveal and analyze light patterns that encode different types of everyday information. In the second part, we verified the results from the first part by asking another group of participants about their understanding of information encoded with light. Together, our results allowed us to establish light patterns and guidelines for building new ambient light systems and applications in the future.

Touch gestures become steadily more important with the ongoing success of touch screen devices. Compared to traditional user interfaces, gestures have the potential to lower cognitive load and the need for visual attention. However, nowadays gestures are defined by designers and developers and it is questionable if these meet all user requirements. In this paper, we present two exploratory studies that investigate how users would use unistroke touch gestures for shortcut access to a mobile phone's key functionalities. We study the functions that users want to access, the preferred activators for gesture execution, and the shapes of the user-invented gestures. We found that most gestures trigger applications, letter-shaped gestures are preferred, and the gestures should be accessible from the lock screen, the wallpaper, and the notification bar. We conclude with a coherent, unambiguous set of gestures for the 20 most frequently accessed functions, which can inform the design of future gesture-controlled applications.

A recent study revealed that every fourth German adult drinks less than 1.5 litres a day. Insufficient fluid intake can cause headache, lack of energy and lightheadedness. Signals can be used to be reminded of drinking. However, these are often missed or even deactivated because they are too obvious. On the basis of a participatory design study, we designed the fashionable light bracelet WaterJewel as an awareness display and an unobtrusive reminder for a regular fluid intake. In a four-week 12-participant study, we explored the use of WaterJewel in daily life and how it compared to a prevalent mobile drinking reminder application. Our results show that with WaterJewel participants drank more in total, more often accomplished the daily drinking goal of 2 litres, drank more regularly, and drank more often prior to the reminder event than with the mobile application. Participants rated WaterJewel as very usable and appreciated its practical and discreet design.

In this paper we report on a participatory design study with young girls. Our goal was to create a mobile phone app to display the spatial proximity of friends in an abstract and privacy-aware manner. A group of 16 girls worked along the user-centred design process to create initial paper-based designs of an app that respects one's friends privacy while displaying their proximity to allow for spontaneous meetings or re-grouping after separation. Our participants created very promising results which we intend to implement and evaluate further against a broader audience.

Diary studies are often applied in HCI research to collect qualitative user impressions. Unfortunately, the period between creation of a diary entry and the later reflection can be too long, which leads to a limited currentness and contextuality. This eventually results in incomplete or misinterpreted data. In this paper we present Storyteller, a mobile application that allows a quick creation of diary entries and encourages users to reflect on these in-situ through a storytelling approach. We argue that this can lead to more accurate and substantial qualitative insights.

Travelers sometimes need to reach a destination in a given amount of time. However, today's navigation systems try to route users to the destination as fast as possible. In this paper, we present the concept of time-based pedestrian navigation. We use a map on a smartphone that highlights streets depending on whether they will lead to a destination in time. Our map also allows the users to choose between route alternatives during the walk.

In this paper, we report about a large-scale in-situ study of tactile feedback for pedestrian navigation systems. Recent advances in smartphone technology have enabled a number of interaction techniques for smartphone that use tactile feedback to deliver navigation information. The aim is to enable eyes-free usage and avoid distracting the user from the environment. Field studies where participants had to fulfill given navigation tasks, have found these techniques to be efficient and beneficial in terms of distraction. But it is not yet clear whether these findings will replicate in in-situ usage. We, therefore, developed a Google Maps-like navigation application that incorporates interaction techniques proposed in previous work. The application was published for free on the Android Market and so people were able to use it as a navigation system in their everyday life. The data collected through anonymous monitoring suggests that tactile feedback is successfully adopted in one third of all trips and has positive effects on the user's level of distraction.

We present PocketMenu, a menu optimized for non-visual, in-pocket interaction with menus on handheld devices with touch screens. By laying out menu items along the border of the touch screen its tactile features guide the interaction. Additional vibro-tactile feedback and speech allows identifying the individual menu items non-visually. In an experiment, we compared PocketMenu with iPhone's VoiceOver. Participants had to control an MP3 player while walking down a road with the device in the pocket. The results provide evidence that in the above context the PocketMenu outperforms VoiceOver in terms of completion time, selection errors, usability. Hence, it enables usage of touch screen apps in mobile contexts (e.g. walking, hiking, or skiing) and limited interaction spaces (e.g. device resting in a pocket).

Going on excursions to explore unfamiliar environments by bike is a popular activity in many places in this world. To investigate the nature of exploratory bicycle trips, we studied tourists on their excursions on a famous vacation island. We found that existing navigation systems are either not helpful or discourage exploration. We therefore propose Tacticycle, a conceptual prototype of a user interface for a bicycle navigation system. Relying on a minimal set of navigation cues, it helps staying oriented while supporting spontaneous navigation and exploration at the same time. In cooperation with a bike rental, we rented the Tacticycle prototype to tourists who took it on their actual excursions. The results show that they always felt oriented and encouraged to playfully explore the island, providing a rich, yet relaxed travel experience. On the basis of these findings, we argue that exploratory trips can be very well supported by providing minimal navigation cues only.

One of the bottlenecks in today's pedestrian navigation system is to communicate the navigation instructions in an efficient but non-distracting way. Previous work has suggested tactile feedback as solution, but it is not yet clear how it should be integrated into handheld navigation systems to improve efficiency and reduce distraction. In this paper we investigate augmenting and replacing a state of the art pedestrian navigation system with tactile navigation instructions. In a field study in a lively city centre 21 participants had to reach given destinations by the means of tactile, visual or multimodal navigation instructions. In the tactile and multimodal conditions, the handheld device created vibration patterns indicating the direction of the next waypoint. Like a sixth sense it constantly gave the user an idea of how the route continues. The results provide evidence that combining both modalities leads to more efficient navigation performance while using tactile feedback only reduces the user's distraction.