Sharif Digital Repository

The main purpose of my research is to present a predictive E-Commerce plan for Iran. For many people the term "electronic commerce" means shopping on the part of the Internet called the World Wide Web, but other technologies such as wireless transmissions on mobile telephone and personal digital assistant devices are also included. In our thesis the term Electronic Commerce or (E-Commerce) is used in its broadest sense, and includes all business activities conducted using electronic data transmission technologies. In Iran e-commerce has achieved an important role and is facing remarkable acceptance in trade operations, therefore my study focuses on the development of E-Commerce model in... 

Conventional induction motors are controlled by stator voltage, so the inverter should pass the full power of the motor. In the doubly-fed rotor wound induction motors, the nominal power of inverter can be reduced. Therefore, these types of machines have been concerned in recent decades and they are able to use as alternative for high power conventional induction machines in the future. Direct torque control is one of the well known methods for controlling the induction motors. Fast torque response and independence of machine parameters (except winding resistance). In this thesis, different sterategies of direct torque control of doubly fed induction motors are presented. In the first... 

In today’s business world, team working as one of the most useful solutions to improve organizational performance and efficiency is used by different organizations and companies. Many experts and academic researchers are focused on teams and team based organizations in their studies and tried to find its cause and effect on organizational performance in the past two decades. Also different variables are recommended as influencing factor on team performance by different authors, In spite of all these researches, no fixed list of these factors, which are been acceptable by reasonable number of researchers and experts, can be find yet. This study tries to present the results of an experimental... 

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... 

After years of disputes on one of the most important challenges in our national economy, finally in Dey 1388 (January 5, 2010) the “Targeted Subsidies Law” was passed by the Iranian parliament. Based on this law, all fiscal (explicit) and quasi-fiscal (implicit) subsidies for goods and services will be removed from the government’s general budget and redistributed among public with a different system. Implementation of the Targeted Subsidies Plan legislation as one of the important decisions in Iran’s economy has widely gotten the attention of economists, scientists and policymakers at industries, universities and other governmental sectors. Firms and other economic actors such as producers... 

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... 

This research enlarges the content of the literature related to the business switching behavior by examining why dissatisfied customers remain in relationship with their existing service provider and do not exit, in the business to business context in Iran. The study develops and tests a model investigating the factors which potentially affect on dissatisfied customers to stay in relationship and also perform upon their repurchase intention. The proposed model specifies a set of propositions among dimensions of switching barriers, switching cost, interpersonal relationship, lack of attractive of alternative, dependence, calculative commitment, service recovery, inertia, lower price, method... 

In this study, the numerical simulation of turbulent flow using Open Source software OpenFOAM, The impact of air flow around the high-rise buildings and classification based on the height and arrangement of the buildings has been against the flow. Numerical method used, the finite volume method uses a piso algorithm, Navier-Stokes equations are solved and the speed and pressure can be obtained. Large Eddy Simulation model is a simulation model used in this software. In general tall buildings against wind loads has three types of move, move along the wind, prependicular along the wind and the twisting motion that occurs at the same time, they are, but, due to the variable nature and...