41 research outputs found

    Challenges of controlling the rotation of virtual objects with variable grip using force-feedback gloves

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    Some virtual reality (VR) applications require true-to-life object manipulation, such as for training or teleoperation. We investigate an interaction technique that replicates the variable grip strength applied to a held object when using force-feedback gloves in VR. We map the exerted finger pressure to the rotational freedom of the virtual object. With a firm grip, the object’s orientation is fixed to the hand. With a loose grip, the user can allow the object to rotate freely within the hand. A user study (N = 21) showed how challenging it was for participants to control the object’s rotation with our prototype employing the SenseGlove DK1. Despite high action fidelity, the grip variability led to poorer performance and increased task load compared to the default fixed rotation. We suspect low haptic fidelity as an explanation as only kinesthetic forces but no cutaneous cues are rendered. We discuss the system design limitations and how to overcome them in future haptic interfaces for physics-based multi-finger object manipulation

    "Seeing the Faces Is So Important" -- Experiences From Online Team Meetings on Commercial Virtual Reality Platforms

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    During the Covid-19 pandemic, online meetings became common for daily teamwork in the home office. To understand the opportunities and challenges of meeting in virtual reality (VR) compared to video conferences, we conducted the weekly team meetings of our human-computer interaction research lab on five off-the-shelf online meeting platforms over four months. After each of the 12 meetings, we asked the participants (N = 32) to share their experiences, resulting in 200 completed online questionnaires. We evaluated the ratings of the overall meeting experience and conducted an exploratory factor analysis of the quantitative data to compare VR meetings and video calls in terms of meeting involvement and co-presence. In addition, a thematic analysis of the qualitative data revealed genuine insights covering five themes: spatial aspects, meeting atmosphere, expression of emotions, meeting productivity, and user needs. We reflect on our findings gained under authentic working conditions, derive lessons learned for running successful team meetings in VR supporting different kinds of meeting formats, and discuss the team's long-term platform choice.Comment: This article has been published at Frontiers in Virtual Reality, Research Topic "Everyday Virtual and Augmented Reality: Methods and Applications, Volume II": https://doi.org/10.3389/frvir.2022.94579

    Quality of life after brain injury in children and adolescents (QOLIBRI-KID/ADO)-The first disease-specific self-report questionnaire after traumatic brain injury

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    The subjective impact of the consequences of pediatric traumatic brain injury (pTBI) on different life dimensions should be assessed multidimensionally and as sensitively as possible using a disease-specific health-related quality of life (HRQoL) instrument. The development and psychometrics of the first such self-report questionnaire for children and adolescents after TBI are reported here. Focus group interviews with children, adolescents, and their parents, cognitive debriefing, item pool generation and reduction using Delphi expert panels were performed. The resulting version was psychometrically tested on 300 individuals aged 8–17 years. After item reduction based on factor analyses, differential item functioning, reliability, and validity were investigated. The final 35 items were associated with six scales (Cognition, Self, Daily Life and Autonomy, Social Relationships, Emotions, Physical Problems). Internal consistency and construct validity were satisfactory. Health-related Quality of life (HRQoL) was significantly lower in older and in female participants, as well as those with cognitive disabilities, anxiety, depression and post-concussion symptoms, than in comparative groups. The new QOLIBRI-KID/ADO is a comprehensive, multidimensional, reliable, and valid instrument, comparable in content and items to the QOLIBRI adult version. Therefore, disease-specific HRQoL can now be measured across the lifespan and may support the amelioration of treatment, care, rehabilitation, and daily life of children and adolescents after TBI.This research was funded by Dr. Senckenbergische Stiftung/Clementine Kinderhospital Dr. Christ‘sche Stiftungen (Germany), and Uniscientia Stiftung (Switzerland)

    Monogenic variants in dystonia: an exome-wide sequencing study

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    Background Dystonia is a clinically and genetically heterogeneous condition that occurs in isolation (isolated dystonia), in combination with other movement disorders (combined dystonia), or in the context of multisymptomatic phenotypes (isolated or combined dystonia with other neurological involvement). However, our understanding of its aetiology is still incomplete. We aimed to elucidate the monogenic causes for the major clinical categories of dystonia. Methods For this exome-wide sequencing study, study participants were identified at 33 movement-disorder and neuropaediatric specialty centres in Austria, Czech Republic, France, Germany, Poland, Slovakia, and Switzerland. Each individual with dystonia was diagnosed in accordance with the dystonia consensus definition. Index cases were eligible for this study if they had no previous genetic diagnosis and no indication of an acquired cause of their illness. The second criterion was not applied to a subset of participants with a working clinical diagnosis of dystonic cerebral palsy. Genomic DNA was extracted from blood of participants and whole-exome sequenced. To find causative variants in known disorder-associated genes, all variants were filtered, and unreported variants were classified according to American College of Medical Genetics and Genomics guidelines. All considered variants were reviewed in expert round-table sessions to validate their clinical significance. Variants that survived filtering and interpretation procedures were defined as diagnostic variants. In the cases that went undiagnosed, candidate dystonia-causing genes were prioritised in a stepwise workflow. Findings We sequenced the exomes of 764 individuals with dystonia and 346 healthy parents who were recruited between June 1, 2015, and July 31, 2019. We identified causative or probable causative variants in 135 (19%) of 728 families, involving 78 distinct monogenic disorders. We observed a larger proportion of individuals with diagnostic variants in those with dystonia (either isolated or combined) with coexisting non-movement disorder-related neurological symptoms (100 [45%] of 222;excepting cases with evidence of perinatal brain injury) than in those with combined (19 [19%] of 98) or isolated (16 [4%] of 388) dystonia. Across all categories of dystonia, 104 (65%) of the 160 detected variants affected genes which are associated with neurodevelopmental disorders. We found diagnostic variants in 11 genes not previously linked to dystonia, and propose a predictive clinical score that could guide the implementation of exome sequencing in routine diagnostics. In cases without perinatal sentinel events, genomic alterations contributed substantively to the diagnosis of dystonic cerebral palsy. In 15 families, we delineated 12 candidate genes. These include IMPDH2, encoding a key purine biosynthetic enzyme, for which robust evidence existed for its involvement in a neurodevelopmental disorder with dystonia. We identified six variants in IMPDH2, collected from four independent cohorts, that were predicted to be deleterious de-novo variants and expected to result in deregulation of purine metabolism. Interpretation In this study, we have determined the role of monogenic variants across the range of dystonic disorders, providing guidance for the introduction of personalised care strategies and fostering follow-up pathophysiological explorations

    Triggermuscle: Exploring Weight Perception for Virtual Reality Through Adaptive Trigger Resistance in a Haptic VR Controller

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    It is challenging to provide users with a haptic weight sensation of virtual objects in VR since current consumer VR controllers and software-based approaches such as pseudo-haptics cannot render appropriate haptic stimuli. To overcome these limitations, we developed a haptic VR controller named Triggermuscle that adjusts its trigger resistance according to the weight of a virtual object. Therefore, users need to adapt their index finger force to grab objects of different virtual weights. Dynamic and continuous adjustment is enabled by a spring mechanism inside the casing of an HTC Vive controller. In two user studies, we explored the effect on weight perception and found large differences between participants for sensing change in trigger resistance and thus for discriminating virtual weights. The variations were easily distinguished and associated with weight by some participants while others did not notice them at all. We discuss possible limitations, confounding factors, how to overcome them in future research and the pros and cons of this novel technology

    Die Zusammenarbeit von Kommunen und Zivilgesellschaft in der Arbeit mit Geflüchteten: Beispiele aus NRW

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    Bonfert L, König C. Die Zusammenarbeit von Kommunen und Zivilgesellschaft in der Arbeit mit Geflüchteten: Beispiele aus NRW. In: Bendel P, Krennerich M, Zentralinstitut für Regionenforschung, eds. Flucht und Menschenrechte: Ergebnisse eines Gesellschaftswissenschaftlichen Kollegs der Studienstiftung des deutschen Volkes. Erlanger Migrations- und Integrationsstudien. Vol 7. 1st ed. Erlangen: FAU University Press; 2020: 171-192.Diese Studie widmet sich der Perspektive zivilgesellschaftlicher Akteurinnen auf ihre Rolle in der kommunalen Arbeit mit Geflüchteten in Deutschland. Während viele Kommunen zivilgesellschaftliches Engagement schätzen und es auf verschiedene Art und Weise unterstützen, bleibt die Einbindung entsprechender Akteurinnen vielerorts vor allem aufgrund fehlender Strukturen ein Problem. In Einzelgesprächen mit Haupt- und Ehrenamtlichen aus der Arbeit mit Geflüchteten behandelt diese Studie deshalb die Frage, wie Aufgaben derzeit zwischen Kommunen und Zivilgesellschaft verteilt sind und wie sie besser verteilt werden könnten. Während die Zusammenarbeit mit der Kommune insgesamt sehr positiv bewertet wird, identifizieren Interviewpartnerinnen insbesondere fehlende finanzielle Mittel und unklare Kommunikationsstrukturen als Hindernisse für eine verbesserte Kooperation zwischen Kommune und Zivilgesellschaft

    AMBIENT QUASICONFORMAL HOMOGENEITY OF PLANAR DOMAINS

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    Abstract. We prove that the ambient quasiconformal homogeneity constant of a hyperbolic planar domain which is not simply connected is uniformly bounded away from 1. We also consider a component Ω0 of a finitely generated Kleinian group Γ. We show that if Ω0/Γ is compact, then Ω0 is uniformly ambiently quasiconformally homogeneous, and that if Ω0 is not simply connected and its quotient Ω0/Γ is non-compact, then it is not uniformly quasiconformally homogeneous. 1
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