Sharif Digital Repository

ISO 10303 Standard also known as STEP, is an standard in the domain of mechanical manufacturing that describes data relating to drawings, design, machining, process planning, engineering and other aspects of product which all together can describe the entire life cycle of products. However, as this standard is newly born and developing these data models are expensive and time consuming, so far, no data model for description of cutting tools is developed. In this project we study the STEP parts and protocols to understand how data is stored. We study EXPRESS Modeling language, the language developed as part of the STEP standard which is the official language of data modeling in STEP. And use... 

Question and answer systems offer a means to acquire information in various formats. One such method is conversational question and answer, where the system possesses a text containing the information and, through a series of exchanges, provides the user with the needed information. In most systems, the responses generated by the system are either single-word or very brief, which is considered a weakness. Recent research endeavors have employed pre-trained language models to bring the system-generated responses closer to natural language. In a recent study, a system receives a set of questions along with short answers, then produces complete and fluent responses. This method utilizes parsers... 

Nowadays, in many financial markets, policy makers impose daily price limit to prevent investors from making emotional decisions, which can lead to abnormal price volatility. A number of theoretical and empirical studies have been conducted on the effectiveness of setting price limit, some supporting the idea and other rejecting. In this research, we begin with a detailed analysis of magnet effect as one of the consequences of setting price limit. Then we study the stock price of five firms listed in Tehran Stock Exchange (TSE) by means of an autoregressive model with explanatory variables to determine whether or not the magnet effect exists. These five firms, put together, comprise 23% of... 

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... 

In the recent years, females’ literacy rate has experienced a drastic improvement in Iran; accordingly a remarkable increase in their participation rate is reasonably expected. Education is considered as a one of driving forces of females’ presence in the labor market; however they likely are paid less than men in some occupations or activities. This phenomenon is called gender wage gap in the labor market literature. This wage gap occurs when a worker is paid less than her counterpart with the same level of marginal product.
This study provides quantitative estimates of the gender gap in the labor market of Iran. In this end, using data on household income and expenditure, from 2005... 

In this thesis, different systems of quantified modal logic, philosophical theories of possibilism and actualism, and the interaction between these two theories and those systems have been studied.Modal claims, which talk about the world as it could have been and not the world as it is, have by far been under philosophical considerations. Possibilism and actualism, two philosophical theses that have their own point of view towards the world and its objects, analyze these claims and their relevant truth-assigning mechanisms in different ways.On the other hand, over the last century, modal sentences have been formulated, in sentencial and quantified levels, by precise logical systems, called... 

Parkinson's disease is the most common progressive neurological disorder after Alzheimer, which is associated with motor disabilities. One of the most effective ways to improve patient’s condition with this disease, is rehabilitation.Assessment of the patient during rehabilitation is very important in order to give a better understanding of patient's status to the specialist, but qualitative assessment methods in traditional rehabilitation are ineffective in fast and accurate evaluation of the patient's condition; and because of their need for patient’s attendance in clinic, they will incur huge medical costs. Therefore, the purpose of the present study is to present a quantitative method to... 

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...