Sharif Digital Repository

Quality of Experience (QoE) indicates the overall quality of one service such as Voice over IP (VoIP) from users' point of view by considering several systems, human, and contextual factors. QoE measurement and prediction are more challenging than Quality of Service (QoS) which is only related to network parameters. There exist various objective and subjective methods for QoE prediction. This research investigates various features affecting QoE by proposing a comprehensive subjective evaluation by employing a large number of users. We show that many unconsidered factors including speaker specifications and signal properties, such as signal-to-noise ratio (SNR), can affect QoE so that the SNR... 

The advent of Quantum Mechanics in the beginning of twentieth century created a fundamental evolution on physics. The ability and performance of Quantum Mechanics in perception of natural phenomena have spread its penetration farther than physics and affected different realms of science, and especially Philosophy. As a result, several philosophic and logical principles defined according to the Quantum Mechanics, and also several of them were rejected because of their inconsistency with Quantum Mechanics. Since Quantum Mechanics was not flawless theory, some of these evolutions have created profound deviations in interpretation and perception of nature. One of these changes was denial of... 

This study inspects the flexural response of RC beams at the presence of compressive GFRP bars as well as tensile bars. Total of 9 reinforced beams were investigated. Three values of tensile reinforcement percentage were considered. For each tensile reinforcement value, three types of compressive reinforcement were taken into account which are classified into zero compressive bars, less than tensile reinforcement value and similar to tensile reinforcement value. The concrete was used in this study is C45 and as a constant parameter.Specimens were tested with four-point bending method using the actuator equipped at the strong floor laboratory to attain maximum flexural strength and... 

Condition monitoring of machinery is of significant economic importance to mitigate production losses resulting from downtimes. Unforeseen failure of roller element bearings is the most common issue observed in industrial units. However, detecting and tracking the progression of these failures through machine vibration monitoring and predicting the deterioration of these rotating components are viable solutions. Numerous studies have focused on using laboratory accelerated life test data for fault detection and remaining useful life prediction of these components. While online monitoring of all equipment in the industry may not be feasible, and conditions in the field differ from laboratory... 

Intelligent predictive maintenance is recognized as a cornerstone of Industry 4.0, where intelligent software is employed for the early detection of faults and the prevention of unexpected failures. Recent research indicates that the integration of multi-sensor data for fault diagnosis of gearboxes and bearings, using artificial intelligence models, has been successful. However, conventional methods face several challenges. These include an over-reliance on the signal characteristics of a single sensor and the impracticality of applying intelligent learning methods, particularly deep learning, despite their high potential, due to the unavailability of sufficiently large and diverse... 

Combination of 3D IC technology and network on chip (NoC) is an effective solution to increase system scalability, and also alleviate the interconnect problem in large scale integrated circuits. However, due to the increased power density in 3D NoC systems and the destructive impact of high temperatures on chip reliability, applying thermal management solutions becomes crucial in such circuits. Since hardware thermal control techniques, such as DVFS, can cause significant degradation on chip performance, in this thesis we propose a runtime distributed migration algorithm based on game theory to balance the heat dissipation among processing elements (PEs) in 3D NoCs. The objective of this...