@phdthesis{Wiebusch2016,
  author    = {Wiebusch, Dennis},
  title     = {Reusability for Intelligent Realtime Interactive Systems},
  publisher = {W{\"u}rzburg University Press},
  address   = {W{\"u}rzburg},
  isbn      = {978-3-95826-040-5 (print)},
  doi       = {10.25972/WUP-978-3-95826-041-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121869},
  school      = {W{\"u}rzburg University Press},
  pages     = {260},
  year      = {2016},
  abstract  = {Software frameworks for Realtime Interactive Systems (RIS), e.g., in the areas of Virtual, Augmented, and Mixed Reality (VR, AR, and MR) or computer games, facilitate a multitude of functionalities by coupling diverse software modules. In this context, no uniform methodology for coupling these modules does exist; instead various purpose-built solutions have been proposed. As a consequence, important software qualities, such as maintainability, reusability, and adaptability, are impeded. Many modern systems provide additional support for the integration of Artificial Intelligence (AI) methods to create so called intelligent virtual environments. These methods exacerbate the above-mentioned problem of coupling software modules in the thus created Intelligent Realtime Interactive Systems (IRIS) even more. This, on the one hand, is due to the commonly applied specialized data structures and asynchronous execution schemes, and the requirement for high consistency regarding content-wise coupled but functionally decoupled forms of data representation on the other. This work proposes an approach to decoupling software modules in IRIS, which is based on the abstraction of architecture elements using a semantic Knowledge Representation Layer (KRL). The layer facilitates decoupling the required modules, provides a means for ensuring interface compatibility and consistency, and in the end constitutes an interface for symbolic AI methods.},
  subject      = {Virtuelle Realit{\"a}t},
  language  = {en}
}
@phdthesis{Fischbach2017,
  author    = {Fischbach, Martin Walter},
  title     = {Enhancing Software Quality of Multimodal Interactive Systems},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-152723},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2017},
  abstract  = {Multimodal interfaces (MMIs) are a promising human-computer interaction paradigm. They are feasible for a wide rang of environments, yet they are especially suited if interactions are spatially and temporally grounded with an environment in which the user is (physically) situated. Real-time interactive systems (RISs) are technical realizations for situated interaction environments, originating from application areas like virtual reality, mixed reality, human-robot interaction, and computer games. RISs include various dedicated processing-, simulation-, and rendering subsystems which collectively maintain a real-time simulation of a coherent application state. They thus fulfil the complex functional requirements of their application areas. Two contradicting principles determine the architecture of RISs: coupling and cohesion. On the one hand, RIS subsystems commonly use specific data structures for multiple purposes to guarantee performance and rely on close semantic and temporal coupling between each other to maintain consistency. This coupling is exacerbated if the integration of artificial intelligence (AI) methods is necessary, such as for realizing MMIs. On the other hand, software qualities like reusability and modifiability call for a decoupling of subsystems and architectural elements with single well-defined purposes, i.e., high cohesion. Systems predominantly favour performance and consistency over reusability and modifiability to handle this contradiction. They thus accept low maintainability in general and hindered scientific progress in the long-term. This thesis presents six semantics-based techniques that extend the established entity-component system (ECS) pattern and pose a solution to this contradiction without sacrificing maintainability: semantic grounding, a semantic entity-component state, grounded actions, semantic queries, code from semantics, and decoupling by semantics. The extension solves the ECS pattern's runtime type deficit, improves component granularity, facilitates access to entity properties outside a subsystem's component association, incorporates a concept to semantically describe behavior as complement to the state representation, and enables compatibility even between RISs. The presented reference implementation Simulator X validates the feasibility of the six techniques and may be (re)used by other researchers due to its availability under an open-source licence. It includes a repertoire of common multimodal input processing steps that showcase the particular adequacy of the six techniques for such processing. The repertoire adds up to the integrated multimodal processing framework miPro, making Simulator X a RIS platform with explicit MMI support. The six semantics-based techniques as well as the reference implementation are validated by four expert reviews, multiple proof of concept prototypes, and two explorative studies. Informal insights gathered throughout the design and development supplement this assessment in the form of lessons learned meant to aid future development in the area.},
  subject      = {Echtzeitsystem},
  language  = {en}
}
@phdthesis{Cronje2024,
  author    = {Cronj{\´e}, Johrine},
  title     = {Trust towards Virtual Humans in Immersive Virtual Reality and Influencing Factors},
  doi       = {10.25972/OPUS-34814},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-348143},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {Virtual humans (VHs) hold immense potential for collaboration in social virtual reality (VR). As VR technology advances, it's vital to assess the psychological effects on VH trust and user privacy to build meaningful social interactions in VR. In social VR, users must be able to trust the VHs they interact with as they navigate through socio-cultural activities. The evaluation of trustworthiness in VHs profoundly impacts interaction quality and user willingness to engage. Conversely, untrustworthy VHs can harm user experiences, privacy, and VR engagement. To address this, we conducted immersive VR studies, exploring how psychological factors influence user's VH trust evaluation under various psychological conditions. This research is pivotal for developing strategies to enhance user privacy, establish secure VR environments, and create a foundation of trust that supports immersive socio-cultural experiences in VR. To date, there are no established interpersonal trust measurement tools specifically for VHs in VR. In study 1 (the familiarity study) of the current thesis the VR-adjusted version of the social conditioned place preference paradigm (SCPP) by Kiser et al., (2022) was identified as a potential trust measurement tool. We tested whether the familiarity of a VH influenced trust as measured with the SCPP paradigm and other self-defined outcome measures, in a Computer Augmented Virtual Environment (CAVE). The CAVE is a VR system that combines immersive VR with real-world elements. It consists of a room-sized space where the walls are used as projection screens to display virtual scenes and objects. In this within - subject design (n = 20), half of the participants were familiarized with one VH and tasked to explore and interact in a realistic looking virtual art museum environment. The participant's evaluation of the VH's trustworthiness was measured as well as their subsequent trust behaviours. Results revealed no significant differences in the evaluation of the VH's trustworthiness nor any behavioural differences between conditions. The findings of the impact of a VH's familiarity on trust is inconclusive due to the major limitations of the paradigm. We concluded that the SCPP paradigm needs further validation and the proposed proxies of trust need to be re-evaluated. The findings were considered in the following study. The virtual maze paradigm design of Hale, (2018) was identified as a potential trust measurement tool, however several limitations are associated with its use to measure trust in VR. In study 2 (a validation study), improvements were made to the virtual maze paradigm of Hale, (2018) and a variant of this paradigm was implemented. We conducted a validation study with 70 participants in a between-subject design with VH trustworthiness as the between-subject factor. Participants wore a head-mounted display (HMD), to deliver an immersive VR experience. In our version of the virtual maze, it was the task of the users (the trustors) to navigate through a maze in VR, where they could interact with a VH (the trustee). They could choose to ask for advice and follow the advice from the VH if they wanted to. The number of times participants asked and followed advice and the time it took to respond to the given advice served as behavioural proxies/measures of trust. The two conditions (trustworthy vs. untrustworthy) did not differ in the content of the advice but in the appearance, tone of voice and engagement of the trustees (allegedly an avatar controlled by other participants). Results indicated that the experimental manipulation was successful, as participants rated the VH as more trustworthy in the trustworthy condition compared with the VH in the untrustworthy condition. Importantly, this manipulation affected the trust behaviour of participants, who, in the trustworthy condition, asked for advice and followed advice more often, indicating that the paradigm is sensitive to differences in VH's trustworthiness. Thus, our paradigm can be used to measure differences in interpersonal trust towards VHs and may serve as a valuable research tool for researchers who study trust in VR. Therefore, study 2 fills the gap in the literature, for an interpersonal trust measurement tool specifically for VHs in VR. Two experimental studies, with a sample size of 50 participants each, utilized the virtual maze paradigm where participants entered 12 rooms under different conditions. We examined the influence of cognitive load (CL) on trust towards VH in VR in study 3 (Cognitive load study), and the influence of emotional affect (Emotional affect study) on trust towards VH in VR in study 4 (EA study). In both studies, we assessed participant's evaluation of a VH's trustworthiness, along with three behavioural indicators of trust in the maze task: 1) frequency of advice asked, 2) frequency of advice followed, and 3) the time taken by participants to execute the received advice. In study 3, the CL was manipulated with the auditory 1-back task in the high cognitive load condition (HCL). In study 4, the Autobiographical Emotional Memory Task (AEMT) was used to manipulate the EA of participants in the negative emotional affect (NEA) condition. As an additional manipulation, while participants were immersed in VR, they were exposed to 12 negative pictures and sounds that was presented simultaneously to strengthen the initial manipulation. The manipulation of the within-subject factors (CL and EA) was successful in both studies, as significant differences between conditions were observed in both studies (higher CL in the HCL condition and a more negative EA in the NEA condition). However, only CL influenced participant's evaluation of the VH's trustworthiness. The VH were evaluated as significantly more trustworthy after the HCL condition. Despite the difference in trust evaluation, there was no difference in advice asking or following. Participants in study 4 asked and followed advice due to their trust in the VH and asked and followed advice equally often in both conditions. Importantly, significant differences were observed in the participants response times in both studies. In study 3 during the HCL condition participants followed advice quicker. The order in which the conditions were presented influenced the experience of CL. Participants experienced higher levels of CL and responded to advice significantly faster when low cognitive load (LCL) was presented as the first condition compared with LCL as the second condition. In study 4 participants in the NEA condition followed advice slower similar to the findings of study 3. The order in which the conditions were presented had a significant effect on the EA. Participants asked and followed advice less when the NEA condition was presented first compared with when it is presented second. Possible explanations for the findings are discussed in the thesis. Overall, this thesis offers a novel tool for trust measurement (the virtual maze paradigm) and contributes to understanding the role of psychological factors in trust towards virtual humans in virtual reality.},
  subject      = {Virtuelle Realit{\"a}t},
  language  = {en}
}
@inproceedings{OPUS4-31720,
  title     = {Abstracts of the Wuertual Reality XR Meeting 2023},
  editor    = {Neumann, Isabel and Gado, Sabrina and K{\"a}thner, Ivo and Hildebrandt, Lea and Andreatta, Marta},
  edition   = {korrigierte Auflage},
  doi       = {10.25972/OPUS-31720},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-317203},
  pages     = {76},
  year      = {2023},
  abstract  = {The Wuertual Reality XR Meeting 2023 was initiated to bring together researchers from many fields who use VR/AR/XR. There was a focus on applied XR and social VR. In this conference band, you can find the abstracts of the two keynotes, the 34 posters and poster pitches, the 29 talks and the four workshops.},
  subject      = {Virtuelle Realit{\"a}t},
  language  = {en}
}
@inproceedings{OPUS4-31528,
  title     = {Abstracts of the Wuertual Reality XR Meeting 2023},
  editor    = {Neumann, Isabel and Gado, Sabrina and K{\"a}thner, Ivo and Hildebrandt, Lea and Andreatta, Marta},
  doi       = {10.25972/OPUS-31528},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-315285},
  pages     = {76},
  year      = {2023},
  abstract  = {The Wuertual Reality XR Meeting 2023 was initiated to bring together researchers from many fields who use VR/AR/XR. There was a focus on applied XR and social VR. In this conference band, you can find the abstracts of the two keynotes, the 34 posters and poster pitches, the 29 talks and the four workshops.},
  subject      = {Virtuelle Realit{\"a}t},
  language  = {en}
}