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Many children around the globe suffer from spider phobia. Virtual reality exposure therapy is an effective phobia treatment but so far predominantly tailored for adults. A gamified approach utilizing gaze interaction would allow for a more child-friendly and engaging experience, and provide the possibility to foster working mechanisms of exposure therapy. We developed an application called SpEYEders in which children make spiders change in positively connotated ways (e.g., make them dance or shrink) if sufficient visual attention towards them is captured via eye tracking. Thereby, motivation for and positive affects during exposure towards spiders are aspired.

Virtual reality allows users to experience a sense of ownership of a virtual body-a phenomenon commonly known as the body ownership illusion. Researchers and designers aim at inducing a body ownership illusion and creating embodied experiences using avatars-virtual characters that represent the user in the digital world. In accordance with the real world where humans own a body and interact via the body with the environment, avatars thereby enable users to interact with virtual worlds in a natural and intuitive fashion. Interestingly, previous work revealed that the appearance of an avatar can change the behavior, attitude, and perception of the embodying user. For example, research found that users who embodied attractive or tall avatars behaved more confidently in a virtual environment than those who embodied less attractive or smaller avatars. Alluding to the versatility of the Greek God Proteus who was said to be able to change his shape at will, this phenomenon was termed the Proteus effect. For designers and researchers of virtual reality applications, the Proteus effect is therefore an interesting and promising phenomenon to positively affect users during interaction in virtual environments. They can benefit from the limitless design space provided by virtual reality and create avatars with certain features that improve the users' interaction and performance in virtual environments. To utilize this phenomenon, it is crucial to understand how to design such avatars and their characteristics to create more effective virtual reality applications and enhanced experiences. Hence, this work explores the Proteus effect and the underlying mechanisms with the aim to learn about avatar embodiment and the design of effective avatars. This dissertation presents the results of five user studies focusing on the body ownership of avatars, and how certain characteristics can be harnessed to make users perform better in virtual environments than they would in casual embodiments. Hence, we explore methods for inducing a sensation of body ownership of avatars and learn about perceptual and physiological consequences for the real body. Furthermore, we investigate whether and how an avatar's realism and altered body structures affect the experience. This knowledge is then used to induce body ownership of avatars with features connected with high performance in physical and cognitive tasks. Hence, we aim at enhancing the users' performance in physically and cognitively demanding tasks in virtual reality. We found that muscular and athletic avatars can increase physical performance during exertion in virtual reality. We also found that an Einstein avatar can increase the cognitive performance of another user sharing the same virtual environment. This thesis concludes with design guidelines and implications for the utilization of the Proteus effect in the context of human-computer interaction and virtual reality., In der virtuellen Realität können Benutzer:innen einen virtuellen Körper besitzen-ein Phänomen, das allgemein als Körperbesitz-Illusion bekannt ist. Forscher und Designer zielen darauf ab, die Körperbesitz-Illusion mit Hilfe von Avataren-virtuellen Figuren, die Benutzer:innen in der digitalen Welt repräsentieren-zu induzieren, um verkörperte Erlebnisse in der virtuellen Realität zu ermöglichen. Im Einklang mit der realen Welt, in der der Mensch einen Körper besitzt und über den Körper mit der Umwelt interagiert, ermöglichen Avatare den Benutzer:innen, auf natürliche und intuitive Weise mit virtuellen Welten zu interagieren. Interessanterweise zeigten frühere Arbeiten, dass das Aussehen eines Avatars das Verhalten, die Einstellung und die Wahrnehmung der Benutzer:innen verändern kann. So wurde beispielsweise festgestellt, dass Benutzer:innen, die attraktive oder große Avatare verkörperten, sich in einer virtuellen Umgebung selbstbewusster verhielten als jene, die weniger attraktive oder kleinere Avatare verkörperten. In Anspielung auf die Vielseitigkeit des griechischen Gottes Proteus, der Erzählungen zufolge seine Gestalt nach Belieben verändern konnte, wurde dieses Phänomen Proteus-Effekt genannt. Für Designer und Forscher von Anwendungen in der virtuellen Realität ist der Proteus-Effekt daher ein interessantes und vielversprechendes Phänomen, um die Benutzer:innen bei der Interaktion in virtuellen Umgebungen positiv zu beeinflussen. Der grenzenlose Gestaltungsspielraum, den die virtuelle Realität bietet, kann genutzt und Avatare mit bestimmten Merkmalen geschaffen werden, die die Interaktion und Leistung der Benutzer:innen in virtuellen Umgebungen verbessern. Um von diesem Phänomen zu profitieren, ist es wichtig zu verstehen, wie solche Avatare und deren Eigenschaften gestaltet werden sollen, um effektivere Anwendungen in der virtuellen Realität zu entwickeln und verbesserte Benutzungserlebnisse zu generieren. Daher werden in dieser Arbeit der Proteus-Effekt und die zugrundeliegenden Mechanismen mit dem Ziel untersucht, mehr über die Verkörperung von Avataren und die Gestaltung effektiver Avatare zu lernen. In dieser Dissertation werden die Ergebnisse von fünf Nutzer:innenstudien vorgestellt, die sich mit der Verkörperung von Avataren befassen und damit, wie bestimmte Eigenschaften genutzt werden, damit Benutzer:innen in virtuellen Umgebungen mehr leisten können als sie es in anderen Avataren tun würden. Es werden Methoden erforscht, um ein Gefühl der Verkörperung von Avataren zu induzieren, und die daraus resultierenden wahrnehmungsbezogenen und physiologischen Konsequenzen für den echten Körper kennenzulernen. Außerdem wird untersucht, ob und wie der Realismus eines Avatars und veränderte Körperstrukturen das Erlebnis beeinflussen. Dieses Wissen wird dann genutzt, um eine Verkörperung von Avataren mit Merkmalen zu induzieren, die mit einer hohen Leistungsfähigkeit bei physischen und kognitiven Aufgaben assoziiert werden. Dadurch soll die Leistungsfähigkeit von Benutzer:innen in physisch und kognitiv anspruchsvollen Aufgaben in der virtuellen Realität verbessert werden. In dieser Arbeit wurde festgestellt, dass muskulöse und athletische Avatare die körperliche Leistung bei Anstrengung in der virtuellen Realität steigern können. Des Weiteren wurde herausgefunden, dass ein Einstein-Avatar die Leistung eines anderen sich im virtuellen Raum befindenden Nutzers bei kognitiv anspruchsvollen Aufgaben steigern kann. Diese Arbeit endet mit Gestaltungsrichtlinien und Implikationen für die Nutzung des Proteus-Effekts im Kontext der Mensch-Computer-Interaktion und virtuellen Realität.

Rendering haptic sensations while interacting with virtual objects, such as experiencing weight is essential for creating natural virtual reality (VR) experiences. However, accurately providing the forces required to sense an object’s weight poses a demanding challenge. Hence, standard VR setups do not allow users to experience different weight sensations. In this paper, we propose a haptic VR controller design that renders the weight of virtual objects by regulating the mass of the controller through liquid transfer. Our planned system consists of two tracked controllers that contain a water bag. They are connected to a liquid reservoir in the back, to or from which water is transferred to change the weight of the controller. A Microcontroller determines the weight of each reservoir via a bi-directional water pump and a set of solenoid valves. To evaluate the prototype, we are planning to investigate in a study whether our system can enhance the VR experience and sense of presence while lifting and swinging virtual objects. Furthermore we plan to examine, whether the device can be used to amplify avatar embodiment.

Dysfunctional cognitions are a crucial part of depression. Cognitive therapy aims to modify dysfunctional beliefs. Typically, dysfunctional beliefs are questioned, and patients are trained to think of alternative functional beliefs. We developed a computer-assisted, avatar-based adjunct for cognitive therapy that aims to reduce dysfunctional beliefs and symptom severity. Besides, it aims to promote alternative functional beliefs. In a randomized controlled trial with 34 patients diagnosed with major depression currently undergoing inpatient treatment at the university psychiatric hospital in Regensburg, Germany, participants were randomly assigned to receive either treatment as usual (TAU) or computer-assisted avatar-based treatment for dysfunctional beliefs (CAT-DB) in addition to TAU. In CAT-DB participants are faced with a virtual avatar expressing their personal dysfunctional beliefs. Participants are asked to contradict these and express alternative functional beliefs. Assessments of conviction of dysfunctional beliefs, functional beliefs and symptom severity were done shortly before the intervention (pre-treatment), right after the intervention (post-treatment) and 14 days later (follow-up). The reduction in conviction of dysfunctional beliefs and symptom severity, and the increase in conviction of alternative functional beliefs at post-treatment and follow-up were significantly greater for the group receiving CAT-DB. Our study provides an indication in favor of the effectiveness of CAT-DB for depressive patients. It is a simple tool that could support classical cognitive therapy. Further studies at different centres, with larger sample sizes and varying therapeutic contexts are required to prove the effectiveness of our intervention.

Because of its capacity to alter the perception of the surrounding environment, mixed reality technology (MR) has potential for in-the-wild management of anxiety���both chronic (e.g., anxiety disorders) and acute (e.g., situation-induced anxiety). Recently, several components of Cognitive Behavioural Therapy leverage these technologies as part of ongoing cognitive restructuring or as part of relaxation or exposure experiences. However, while most of these researchers focus on the promising benefits of these technologies, a deeper discussion on the potential harm through the misuse of these techniques is still missing. To ignite a conversation about the two sides of the same coin of MR for mental health, we present several scenarios where mixed reality approaches might be used to deceive users rather to support them.

Virtual Reality (VR) allows us to embody any possible appearance using avatars. Previous work found that the visual appearance of an avatar can affect the user’s behavior – a phenomenon known as the Proteus effect. The illusory feeling of owning a virtual avatar – the body ownership illusion – modulates the Proteus effect. Prior investigations revealed that the time of how long users embody an avatar can affect the extent of the body ownership illusion, however, it is currently unknown whether and how behavioral changes caused by the Proteus effect are moderated by the embodiment time. Therefore, we are planning to conduct a study with 30 participants where we induce the Proteus effect using avatars of different perceived ages to evaluate the effect of embodiment time on walking speed. We hypothesize that the longer users embody an elderly avatar, the slower they will walk in VR. In this proposal, we suggest a study design to evaluate the effect of embodiment time on the body ownership illusion and behavioral changes caused by the Proteus effect in VR.

Virtual Reality (VR) allows us to perceive the world through any possible embodiment – the avatar. Behavioral changes due to the strong bond between the user and the virtual avatar is known as Proteus Effect. Previous work found that the Proteus Effect occurs when characteristics of the appearance are associated with knowledge and experiences gained by anticipated entities or stereotypes. Based on the findings that the Proteus Effect can trigger behavioral changes, we hypothesize that the appearance of an avatar in VR can be manipulated in a way that users will perform tasks better than they would perform them using their real or any casual embodiment. As one of the most important human behavioral characteristics is exerting force, we are planning to conduct a study investigating if muscular or wispy avatars are able to change physical forces of the physical self. Our hypothesis is that people will apply more force when they interact in a more powerful-looking appearance. An effect would have far-reaching consequences and implications for the interactions with avatars in HCI and VR.

Money laundering is marginalized phenomenon with high social impact which comes from necessary connection of this activity with illegal activities, especially organized crime. Since the goal of almost every illegal activity is to create profit (and since the biggest profit comes from the activities which are highly dangerous for the society, such as drug trafficking) it is vital for the society to fight money laundering effectively. It is in the best interest of the whole society to fight this phenomenon and cut the organized crime out of their resources through effective control of the money laundering. The goal of this thesis is to explain the issue of money laundering in detail, to map the whole process while using mostly comparative and analytic methods and summarize the international and Czech anti- money laundering legislation. I would be glad if the reader had truly concrete idea about the phenomenon of money laundering after reading my thesis. In the first part, I am dealing with the whole concept of money laundering, meaning history and definition of the term itself. I also compare terms money laundering and legalization of proceeds from crime. Then I analyze the true nature of money laundering and financing of terror and the process of money laundering. I also deal with concrete subjects...

Assessing the user experience (UX) while being immersed in a virtual environment (VE) is crucial to obtain insights about the quality and vividness of the experience created by virtual reality (VR) systems. These valuable insights are necessary to understand a user's response to VEs and, therefore, to advance in VR research. However, a standardized and effective measure for assessing UX is still missing. Consequently, this lack of suitable measures hinders researchers to gain knowledge and understanding about the effects of VEs on users and in turn slows down the progress in VR technology. To tackle this problem, we propose a behavioral measure for assessing UX based on a phenomenon known as the Proteus effect, which describes changes in behavior and attitude due to the embodiment of avatars with stereotypical characteristics. As avatars are a crucial part of an immersive experience, the extent of behavioral changes caused by the embodiment of avatars may pose an opportunity to implicitly quantify the UX of a VE. This paper discusses an alternative behavioral measure and contributes to the debate about suitable methods for assessing UX in VR systems.