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Virtual-reality (VR) is an immersive technology with a growing market and many applications for gesture recognition. This thesis presents a VR gesture recognition method using signal processing techniques. The core concept is based on the comparison of motion features in the form of signals between a runtime recording of users and a possible gesture set. This comparison yields a similarity score through which the most similar gesture can be recognized by a continuous recognition system. Some selected comparison methods are presented, evaluated and discussed. An example implementation is demonstrated. However, due to an introduced layer model parts of the method and its implementation are interchangeable.
Similar or even better performance is achieved compared to other related work. The comparison method Dynamic Time Warping (DTW) reaches an average positive recognitions rate of 98.18% with acceptable real-time application performance. Additionally, the method comes with some benefits: position and direction of users is irrelevant, body proportions have no significant negative impact on recognition rates, faster and slower gesture executions are possible, no user inputs are needed to communicate gesture start and end (continuous recognition), also continuous gestures can be recognized, and the recognition is fast enough to trigger gesture specific events already during the execution.
The increasing availability of online video content, partially fueled by the Covid-19 pandemic and the growing presence of social media, adds to the importance of providing audio descriptions as a media alternative to video content for blind and visually impaired people. In order to address concerns as to what can be sufficiently described and how such descriptions can be delivered to users, a concept has been developed providing audio descriptions in multiple levels of detail. Relevant information is incorporated into an XML-based data structure. The concept also includes a process to provide optional explanations to terms and abbreviations, helping users without specific knowledge or people with cognitive concerns in comprehending complex videos. These features are implemented into a prototype based on the Able Player software. By conducting a user test, the benefits of multi-layered audio descriptions and optional explanatory content are evaluated. Findings suggest that the choice of several levels of detail is received positively. Users acknowledged the concept of explanations played parallelly to the video and described further use cases for such a practice. Participants preferred a higher level of detail for a high-paced action video and a lower level for informative content. Possibilities to extend the data structure and features include multilanguage use cases and distributed systems.
Climate change is one of the greatest societal challenges of our time. The global food production alone accounts for 26% of global greenhouse gas emissions. Without dietary changes, the challenges of climate protection can hardly be achieved in the food sector. Technology has the ability to significantly change society and it can be used to change people’s attitude or behaviors.
The current study investigated the potential of using Persuasive Technology for guiding consumers to implement sustainable food choices. To evaluate its impact, an online grocery store was designed and prototyped using the Persuasive Systems Design model according to Oinas-Kukkonen and Harjumaa. The intended target behavior was to adjust food choices and make sustainable consumption decisions. The target group consisted of individuals between the ages 20 and 34 years.
The iterative approach of the empirical study was divided into four parts: First, the requirements of the target group were analyzed. Then a concept of the grocery online shop was developed using the design principles of the Persuasive Systems Design model. The concept Foodprint was prototypically implemented and consequently, evaluated via A/B testing with target users. Two high-fidelity prototypes were similarly structured with the only difference that Prototype A contained persuasive elements. Prototype B was intended to collect comparative data in the user tests. Ten individuals of the target group evaluated the prototypes and their impressions of the concept and food choices were examined to assess the impact of the Persuasive Systems Design model.
The data were analyzed qualitatively as well as quantitatively. Prototype A – with the persuasive elements – showed a more positive user experience. The evaluation of tests A and B revealed that the persuasive elements were able to influence users to identify sustainable food options.
In general, it can be concluded that testers from both tests, A and B, rated the grocery online store as helpful and would be willing using it in the future. However, it became also evident that the target group lacked knowledge to make informed decisions about the environmental impact of their food choices. As observed in the current study, the participants considered it difficult to assess the sustainability level of foods when grocery shopping. Their purchasing decisions relied on labels and erroneous assumptions. These observations indicate the need for more support in making sustainable food choices.
The Persuasive Systems Design model had the potential to influence the users in their food choices, suggesting that it may be an option to contribute to environmental protection in the food sector. Over time, consumers may even become more aware of the impact of their food choices and hence, could adjust their purchasing behavior in stationary retail stores.
Video games have a significant influence on our time. However, lack of accessibility makes it hard for disabled gamers to play most of them. Virtual reality offers new possibilities to include people with disabilities and enable them to play games. Additionally, serious VR games provide educational benefits, such as improved memory and engagement.
In this work, the accessibility problems in video games and VR applications are explored with an emphasis on serious games as well as a general lack of guidelines. An overview of existing guidelines is given. From this, a set of guidelines is derived that summarizes the relevant rules for accessible VR games.
New ways to interact with VR environments come with both opportunities and challenges. This work investigates the applicability of different hands-free input methods to play a VR game. Using a serious game five focus and three activation methods were implemented exemplary with the Oculus Go. The suitability of these methods was analyzed in a pre-study that excluded head movements for controlling the game. The remaining input methods were evaluated in an explorative user study in terms of operability and ease of use.In summary, all tested methods can be used to control the game. The evaluation shows head-tracking as the preferred input method, while scanning eye-tracking and voice control were rated mediocre.
In addition, the correlation between input methods and different menu types was examined, but the influence turned out to be negligible.
Web Accessibility is becoming increasingly important. Guidelines and according tests were created in order to ensure Web Accessibility for everyone. Detailed reports are created in order to advise content creators on this topic. However, these reports can be even more elaborate than the guidelines themselves with their very specific and technical vocabulary and their sheer length. This makes it hard, especially for non-experts, to understand what the results mean and to know where to start.
StroCards is a functional prototype developed to help viewers of Web Accessibility reports understand their contents easier. One way of doing this is by sorting and filtering identified accessibility issues. It can generate charts from the number of failed, passed and not applicable success criteria that highlight aspects that are not explained in the report itself. It can explain the user how well each of the tested website performs in terms of accessibility regarding different responsibilities. One of its key features is generating individual reports for individual responsibilities like e.g. visual design. With this functionality a designer like in this example, could receive a list of issues that are relevant to them without being overwhelmed by issues that they cannot solve. This creates a more efficient handling of the report. Besides displaying the report highlighting project roles, StroCards can have a more human-centered and empathetic approach by showing which user groups are affected and therefore excluded by accessibility issues on the website. This makes the long list of guidelines more tangible – especially for non-experts.
In the process of developing StroCards, some design decisions were made with a group of experts. The implemented functional prototype was tested in a qualitative and quantitative user study. It was perceived as easier to understand and better to work with.
A tool like this could wildly help people maintaining, creating, and developing websites to put these Web Accessibility guidelines into practice and consequently minimize exclusion of people from websites.