Hear Me Out: Supporting Citizens to Create Comprehensible Contributions on Urban Participation PlatformsUrbanization has increased societal tensions and led to the growth of citizen participation in urban planning, which is often conducted in computer-supported environments and progressively online to include a high number of citizens. Past projects have shown that digital participation creates new challenges and that collaborative online discussions do not achieve the quality of on-site scenarios, as the interactions, in-depth exchange of opinions, and quality of contributions vary. Within a design science research project, we examine \textit{how to support citizens in creating comprehensible contributions on urban participation platforms?} We identify issues, formulate meta-requirements, and derive design principles to implement feasible prototypes that we evaluated in focus groups. Our findings extend the existing research about urban participation platforms in civic tech, urban informatics, and planning, with validated design principles that specify AI-based feedback and further features to increase interactions and support citizens in producing more specific contributions.2024MBMarten Borchers et al.Session 1d: Values and Practices in Crowdsourcing and Citizen ScienceCSCW
Natural Expression of a Machine Learning Model's Uncertainty Through Verbal and Non-Verbal Behavior of Intelligent Virtual AgentsUncertainty cues are inherent in natural human interaction, as they signal to communication partners how much they can rely on conveyed information. Humans subconsciously provide such signals both verbally (e.g., through expressions such as "maybe" or "I think") and non-verbally (e.g., by diverting their gaze). In contrast, artificial intelligence (AI)-based services and machine learning (ML) models such as ChatGPT usually do not disclose the reliability of answers to their users. In this paper, we explore the potential of combining ML models as powerful information sources with human means of expressing uncertainty to contextualize the information. We present a comprehensive pipeline that comprises (1) the human-centered collection of (non-)verbal uncertainty cues, (2) the transfer of cues to virtual agent videos, (3) the annotation of videos for perceived uncertainty, and (4) the subsequent training of a custom ML model that can generate uncertainty cues in virtual agent behavior. In a final step (5), the trained ML model is evaluated in terms of both fidelity and generalizability of the generated (non-)verbal uncertainty behavior.2024SSSusanne Schmidt et al.Eye Tracking & Gaze InteractionAgent Personality & AnthropomorphismExplainable AI (XAI)UIST
Born to Run, Programmed to Play: Mapping the Extended Reality Exergames LandscapeMany people struggle to exercise regularly, raising the risk of serious health-related issues. Extended reality (XR) exergames address these hurdles by combining physical exercises with enjoyable, immersive gameplay. While a growing body of research explores XR exergames, no previous review has structured this rapidly expanding research landscape. We conducted a scoping review of the current state of XR exergame research to (i) provide a structured overview, (ii) highlight trends, and (iii) uncover knowledge gaps. After identifying 1318 papers in human-computer interaction and medical databases, we ultimately included 186 papers in our analysis. We provide a quantitative and qualitative summary of XR exergame research, showing current trends and potential future considerations. Finally, we provide a taxonomy of XR exergames to help future design and methodological investigation and reporting.2024SKSukran Karaosmanoglu et al.Universität HamburgFull-Body Interaction & Embodied InputImmersion & Presence ResearchSerious & Functional GamesCHI
Beyond the Blink: Investigating Combined Saccadic & Blink-Suppressed Hand Redirection in Virtual RealityIn pursuit of hand redirection techniques that are ever more tailored to human perception, we propose the first algorithm for hand redirection in virtual reality that makes use of saccades, i.e., fast ballistic eye movements that are accompanied by the perceptual phenomenon of change blindness. Our technique combines the previously proposed approaches of gradual hand warping and blink-suppressed hand redirection with the novel approach of saccadic redirection in one unified yet simple algorithm. We compare three variants of the proposed Saccadic & Blink-Suppressed Hand Redirection (SBHR) technique with the conventional approach to redirection in a psychophysical study (N=25). Our results highlight the great potential of our proposed technique for comfortable redirection by showing that SBHR allows for significantly greater magnitudes of unnoticeable redirection while being perceived as significantly less intrusive and less noticeable than commonly employed techniques that only use gradual hand warping.2024AZAndré Zenner et al.Saarland University, Saarland Informatics Campus, German Research Center for Artificial Intelligence (DFKI), Saarland Informatics CampusHand Gesture RecognitionFull-Body Interaction & Embodied InputEye Tracking & Gaze InteractionCHI
Turn-It-Up: Rendering Resistance for Knobs in Virtual Reality through Undetectable Pseudo-HapticsRendering haptic feedback for interactions with virtual objects is an essential part of effective virtual reality experiences. In this work, we explore providing haptic feedback for rotational manipulations, e.g., through knobs. We propose the use of a Pseudo-Haptic technique alongside a physical proxy knob to simulate various physical resistances. In a psychophysical experiment with 20 participants, we found that designers can introduce unnoticeable offsets between real and virtual rotations of the knob, and we report the corresponding detection thresholds. Based on these, we present the Pseudo-Haptic Resistance technique to convey physical resistance while applying only unnoticeable pseudo-haptic manipulation. Additionally, we provide a first model of how C/D gains correspond to physical resistance perceived during object rotation, and outline how our results can be translated to other rotational manipulations. Finally, we present two example use cases that demonstrate the versatility and power of our approach.2023MFMartin Feick et al.Force Feedback & Pseudo-Haptic WeightImmersion & Presence ResearchUIST
VR Almost There: Simulating Co-located Multiplayer Experiences in Social Virtual RealityConsumer social virtual reality (VR) applications have recently started to enable social interactions at a distance. Yet it is still relatively unknown if and to what extent such applications provide meaningful social experiences in cases where in-person leisure activities are not feasible. To explore this, we developed a custom social VR application and conducted an exploratory lab study with 25 dyads in which we compared an in-person and a virtual version of a co-located multiplayer scenario. Our mixed-methods analysis revealed that both scenarios created a socially rich atmosphere and strengthened the social closeness between players. However, the lack of facial animations, limited body language, and a low field of view led to VR's main social experiential limitations: a reduced mutual awareness and emotional understanding compared to the in-person scenario. We derive implications for social VR design and research as well as game user research.2023PSPhilipp Sykownik et al.University of Duisburg-EssenSocial & Collaborative VRMultiplayer & Social GamesCHI
Never Skip Leg Day Again: Training the Lower Body with Vertical Jumps in a Virtual Reality ExergameVirtual Reality (VR) exergames can increase engagement in and motivation for physical activities. Most VR exergames focus on the upper body because many VR setups only track the users' heads and hands. To become a serious alternative to existing exercise programs, VR exergames must provide a balanced workout and train the lower limbs, too. To address this issue, we built a VR exergame focused on vertical jump training to explore full-body exercise applications. To create a safe and effective training, nine domain experts participated in our prototype design. Our mixed-methods study confirms that the jump-centered exercises provided a worthy challenge and positive player experience, indicating long-term retention. Based on our findings, we present five design implications to guide future work: avoid an unintended forward drift, consider technical constraints, address safety concerns in full-body VR exergames, incorporate rhythmic elements with fluent movement patterns, adapt difficulty to players' fitness progression status.2023SCSebastian Cmentowski et al.University of Duisburg-EssenFull-Body Interaction & Embodied InputSerious & Functional GamesCHI
Induce a Blink of the Eye: Evaluating Techniques for Triggering Eye Blinks in Virtual RealityAs more and more virtual reality (VR) headsets support eye tracking, recent techniques started to use eye blinks to induce unnoticeable manipulations to the virtual environment, e.g., to redirect users' actions. However, to exploit their full potential, more control over users' blinking behavior in VR is required. To this end, we propose a set of reflex-based blink triggers that are suited specifically for VR. In accordance with blink-based techniques for redirection, we formulate (i) effectiveness, (ii) efficiency, (iii) reliability, and (iv) unobtrusiveness as central requirements for successful triggers. We implement the soft- and hardware-based methods and compare the four most promising approaches in a user study. Our results highlight the pros and cons of the tested triggers, and show those based on the menace, corneal, and dazzle reflexes to perform best. From these results, we derive recommendations that help choosing suitable blink triggers for VR applications.2023AZAndré Zenner et al.Saarland University, Saarland Informatics Campus, German Research Center for Artificial Intelligence (DFKI), Saarland Informatics CampusEye Tracking & Gaze InteractionImmersion & Presence ResearchCHI
Simulating Human Imprecision in Temporal Statements of Intelligent Virtual AgentsResearch on intelligent virtual agents (IVAs) often concerns the implementation of human-like behavior by integrating artificial intelligence algorithms. Thus far, few studies focused on mimicry of cognitive imperfections inherent to humans in IVAs. Neglecting to implement such imperfect behavior in IVAs might result in less believable or engaging human-agent interactions. In this paper, we simulate human imprecision in conversational IVAs' temporal statements. We conducted a survey to identify temporal statement patterns, transferred them to a conversational IVA, and conducted a user study evaluating the effects of time precision on perceived anthropomorphism and usefulness. Statistical analyses reveal significant interaction between time precision and agents' use of memory aids, indicating that (i) imprecise agents are perceived as more human-like than precise agents when responding immediately, and (ii) unnaturally high levels of temporal precision can be compensated for by memory aid use. Further findings underscore the value of continued inquiry into cultural variations.2022SSSusanne Schmidt et al.Universität HamburgIntelligent Voice Assistants (Alexa, Siri, etc.)Agent Personality & AnthropomorphismCHI
Much Realistic, Such Wow! A Systematic Literature Review of Realism in Digital GamesResearchers reference realism in digital games without sufficient specificity. Without clarity about the dimensions of realism, we cannot assess how and when to aim for a higher degree of realism, when lower realism suffices, or when purposeful unrealism is ideal for a game and can benefit player experience (PX). To address this conceptual gap, we conducted a systematic review using thematic synthesis to distinguish between types of realism currently found in the digital games literature. We contribute qualitative themes that showcase contradictory design goals of realism/unrealism. From these themes, we created a framework (i.e., a hierarchical taxonomy and mapping) of realism dimensions in digital games as a conceptual foundation. Our themes and framework enable a workable specificity for designing or analyzing types of realism, equip future work to explore effects of specific realism types on PX, and offer a starting point for similar efforts in non-game applications.2022KRKatja Rogers et al.University of Waterloo, University of WaterlooGame UX & Player BehaviorRole-Playing & Narrative GamesCHI
Feels like Team Spirit: Biometric and Strategic Interdependence in Asymmetric Multiplayer VR GamesVirtual reality (VR) multiplayer games increasingly use asymmetry (e.g., differences in a person’s capability or the user interface) and resulting interdependence between players to create engagement even when one player has no access to a head-mounted display (HMD). Previous work shows this enhances player experience (PX). Until now, it remains unclear whether and how an asymmetric game design with interdependences creates comparably enjoyable PX for both an HMD and a non-HMD player. In this work, we designed and implemented an asymmetric VR game (different in its user interface) with two types of interdependence: \textit{strategic} (difference in game information/player capability) and \textit{biometric} (difference in player’s biometric influence). Our mixed-methods user study (N=30) shows that asymmetries positively impact PX for both player roles, that interdependence strongly affects players’ perception of agency, and that biometric feedback---while subjective---is a valuable game mechanic.2021SKSukran Karaosmanoglu et al.Universität HamburgImmersion & Presence ResearchGame UX & Player BehaviorMultiplayer & Social GamesCHI
Augmented Reality for Older Adults: Exploring Acceptability of Virtual Coaches for Home-based Balance Training in an Aging PopulationBalance training has been shown to be effective in reducing risks of falling, which is a major concern for older adults. Usually, exercise programs are individually prescribed and monitored by physiotherapeutic or medical experts. Unfortunately, supervision and motivation of older adults during home-based exercises cannot be provided on a large scale, in particular, considering an ageing population. Augmented reality (AR) in combination with virtual coaches could provide a reasonable solution to this challenge.<br>We present a first investigation of the acceptance of an AR coaching system for balance training, which can be performed at home. In a human-centered design approach we developed several mock-ups and prototypes, and evaluated them with 76 older adults. The results suggest that older adults find the system encouraging and stimulating. The virtual coach is perceived as an alive, calm, intelligent, and friendly human. However, usability of the entire AR system showed a significant negative correlation with participants' age.2020FMFariba Mostajeran et al.Universität HamburgAR Navigation & Context AwarenessElderly Care & Dementia SupportCHI
Walking by Cycling: A Novel In-Place Locomotion User Interface for Seated Virtual Reality ExperiencesWe introduce VR Strider, a novel locomotion user interface (LUI) for seated virtual reality (VR) experiences, which maps cycling biomechanics of the user's legs to virtual walking movements. The core idea is to translate the motion of pedaling on a mini exercise bike to a corresponding walking animation of a virtual avatar while providing audio-based tactile feedback on virtual ground contacts. We conducted an experiment to evaluate the LUI and our novel anchor-turning rotation control method regarding task performance, spatial cognition, VR sickness, sense of presence, usability and comfort in a path-integration task. The results show that VR Strider has a significant positive effect on the participants' angular and distance estimation, sense of presence and feeling of comfort compared to other established locomotion techniques, such as teleportation and joystick-based navigation. A confirmatory study further indicates the necessity of synchronized avatar animations for virtual vehicles that rely on pedalling.2020JFJann Philipp Freiwald et al.Universität HamburgFull-Body Interaction & Embodied InputImmersion & Presence ResearchCHI
Transformation through Provocation?Can a chatbot enable us to change our conceptions, to be critically reflective? To what extent can interaction with a technologically 'minimal' medium such as a chatbot evoke emotional engagement in ways that can challenge us to act on the world? In this paper, we discuss the design of a provocative bot, a 'bot of conviction', aimed at triggering conversations on complex topics (e.g. death, wealth distribution, gender equality, privacy) and, ultimately, soliciting specific actions from the user it converses with. We instantiate our design with a use case in the cultural sector, specifically a Neolithic archaeological site that acts as a stage of conversation on such hard themes. Our larger contributions include an interaction framework for bots of conviction, insights gained from an iterative process of participatory design and evaluation, and a vision for bot interaction mechanisms that can apply to the HCI community more widely.2019MRMaria Roussou et al.National and Kapodistrian University of AthensConversational ChatbotsParticipatory DesignCHI
Who is Addressed in this Comment? Automatically Classifying Meta-Comments in News CommentsUser comments have become an essential part of online journalism. However, newsrooms are often overwhelmed by the vast number of diverse comments, for which a manual analysis is barely feasible. Identifying meta-comments that address or mention newsrooms, individual journalists, or moderators and that may call for reactions is particularly critical. In this paper, we present an automated approach to identify and classify meta-comments. We compare comment classification based on manually extracted features with an end-to-end learning approach. We develop, optimize, and evaluate multiple classifiers on a comment dataset of the large German online newsroom SPIEGEL Online and the "One Million Posts" corpus of DER STANDARD, an Austrian newspaper. Both optimized classification approaches achieved encouraging F0.5 values between 76% and 91%. We report on the most significant classification features with the results of a qualitative analysis and discuss how our work contributes to making participation in online journalism more constructive.2018MHMarlo Häring et al.Ratings, Comments, and FeedbackCSCW