Sharif Digital Repository

Process Planning is the link between CAD and CAM and is one of the most complex issues in product development chain. In addition, this process is time-consuming, costly and requires expert man power. In recent decades, many Computer Aided Process Planning (CAPP) systems are developed to reduce the duration of Process Planning and many feature based process planning systems have been reported. Feature recognition and determining the precedence of machining features are the most critical issues in feature-based process planning. It gets more complicated where geometric interaction occurs between machining features. This work, focuses on feature recognition and their geometric interactions and... 

According to the rise of turnover and pace of trading, accelerating of analysis and making decision is unavoidable. Humans are unable to analyze big data quickly without behavioral biases so, using machines to analyze big data seems critical. Hence, financial markets tend to apply algorithmic trading in which some techniques like data mining and machine learning are notable. OLPS which sequentially allocates capital among a set of assets aiming to maximize the final return of investment in the long run, is the core problem in algorithmic trading. This article presents an online portfolio selection algorithm. The online portfolio selection sequentially selects a portfolio over a set of assets... 

The purpose of this study is to model the long-term effects of taxes on different aspects of private cars upon auto ownership and use, and thereby auto industries in producing more fit cars, so as to minimize auto emission. It involves used car market, different car demands and auto industry production. The study follows some previous studies in this area and tries to enhance the various aspects of the model by directing it toward a more real situation. In order to visualize the effects of the model, it has been applied on the case of Shiraz in 1378. It has been shown that the model was able to reduce air pollution and fuel consumption by 90% and 50%, respectively, as compared to the “Do... 

Cold roll forming is a process for manufacturing of long sheet metal products with constant cross sections. The base of this process is bending and formation of plastic deformation in sheet. In this process, bending operation occurs in several forming stations. The purpose of this project is estimation of the distance between stations in roll forming. This work is based on determination of deformation length. In this study, first, the researches done in the roll forming is expressed. Then, a relation for estimation of deformation length has been derived that could be used in different stages of roll forming. Compared with other works, the work hardening effect has been considered in the... 

The Darcy’ law is valid for low velocity or low Reynolds number where merely viscous force is responsible for pressure loss in the porous media. At higher velocity, because of inertial forces and turbulency, the pressure loss would be higher than Darcy’ law estimates; therefore at these flow regimes the Darcy’ law is no longer valid. Hence, consideration of Non-Darcy flow effect is necessary to sufficiently model high gas velocity effects. The velocity is high in gas reservoirs especially those ones that are considered for underground gas storage. In this study, the effects of Non-Darcy flow on several parameters such as; estimation of differential pressure, flowing bottom hole pressure,... 

Author identification using statistical methods is a branch of authorship attribution which is one of important problems in natural language processing. Using different statistical methods, an anonymous text is attributed to an author. One of the primary parts of the task is to choose the appropriate stylistic features of the text in order to study the significances of style. These features must be quantitatively studied and could be extracted in lexical level, character level, and syntactic or semantic levels. The next step is text classification in which different machine learning methods such as decision tree, Artificial Neural Networks, Naïve Bayes and other methods could be used.... 

The problem of Origination of The Universe is one of the most important issues in the history of philosophy whether in western edition or in Islamic thought. The most problematic aspect of the Origination is Temporal Origination. From about 30 years ago as a result of the works of a famous American philosopher William Lane Craig, the debate between temporality and Eternity of the Universe became a fresh topic in western philosophy. In this research we want to survey the philosophical arguments for and against the temporality of the Universe based on the views of: W.L.Craig, Q.Smith and Allamah S.M.H Al-Tabatabaie.