This Master's thesis deals with using the theory of fuzzy logic in building up a model of suppliers evaluation of Heidelberg Slovakia company. Using the model the company will obtain an image about the efficiency and reliability of its suppliers. The information can be used to decision making support in supply chain management.

Haptic-based Virtual Reality (VR) applications have many merits. What is still obscure, from the designer’s perspective of these applications, is the experience the users will undergo when they use the VR system. Quality of Experience (QoE) is an evaluation metric from the user’s perspective that unfortunately has received limited attention from the research community. Assessing the QoE of VR applications reflects the amount of overall satisfaction and benefits gained from the application in addition to laying the foundation for ideal user-centric design in the future. In this thesis, we address certain issues and concerns regarding QoE of virtual environments. In essence, we propose a taxonomy for the evaluation of the QoE for multimedia applications and in particular VR applications. The taxonomy classifies QoE related parameters into groups. The groups’ organization is generated from the definition we have adopted for the QoE which is the Quality of Service (QoS) plus the user experience (UX). We model this taxonomy using first mathematical modeling based on weighted averages and then a Fuzzy logic Inference System (FIS) to quantitatively measure the QoE of haptic virtual environments. We test both models conducting user study analysis to evaluate the QoE of a VR application. These models serve as engines that facilitate the calculation of QoE with minimal amount of users. We specifically attend to the issue of the new media, haptics, within the context of increasing the QoE of virtual environments (VE). This special attention is important for comparing the effect of tactile and kinesthetic feedback on the QoE. In accordance, we investigate a particular topic that seems to have a colossal effect on QoE throughout our analysis, which is fatigue. Our analysis involved users' studies since the main focus is on the user. The QoE for virtual environments is in its primary stages. This thesis tackles issues that are vital in dealing with and understanding the importance of QoE. The various results suggest a positive user's disposition toward haptics and virtual environments, yet there will always be obstacles and challenges such as fatigue that if minimized will enhance the QoE of haptic-based applications.

Haptic-based Virtual Reality (VR) applications have many merits. What is still obscure, from the designer’s perspective of these applications, is the experience the users will undergo when they use the VR system. Quality of Experience (QoE) is an evaluation metric from the user’s perspective that unfortunately has received limited attention from the research community. Assessing the QoE of VR applications reflects the amount of overall satisfaction and benefits gained from the application in addition to laying the foundation for ideal user-centric design in the future. In this thesis, we address certain issues and concerns regarding QoE of virtual environments. In essence, we propose a taxonomy for the evaluation of the QoE for multimedia applications and in particular VR applications. The taxonomy classifies QoE related parameters into groups. The groups’ organization is generated from the definition we have adopted for the QoE which is the Quality of Service (QoS) plus the user experience (UX). We model this taxonomy using first mathematical modeling based on weighted averages and then a Fuzzy logic Inference System (FIS) to quantitatively measure the QoE of haptic virtual environments. We test both models conducting user study analysis to evaluate the QoE of a VR application. These models serve as engines that facilitate the calculation of QoE with minimal amount of users. We specifically attend to the issue of the new media, haptics, within the context of increasing the QoE of virtual environments (VE). This special attention is important for comparing the effect of tactile and kinesthetic feedback on the QoE. In accordance, we investigate a particular topic that seems to have a colossal effect on QoE throughout our analysis, which is fatigue. Our analysis involved users' studies since the main focus is on the user. The QoE for virtual environments is in its primary stages. This thesis tackles issues that are vital in dealing with and understanding the importance of QoE. The various results suggest a positive user's disposition toward haptics and virtual environments, yet there will always be obstacles and challenges such as fatigue that if minimized will enhance the QoE of haptic-based applications.