Sharif Digital Repository

Investigation of possible vibratory responses of dynamical systems around their stable equilibria is an essential step which must be taken before their both design and application. The attained results of such a study can largely help to prevent instability in closed-loop stabilized systems by avoiding excitation of the system in the neighborhood of its resonance. In this paper, nonlinear oscillations of a Rotary Inverted Pendulum (RIP) enjoying a full-state feedback controller is investigated. Lagrange’s equations are employed to derive an accurate 2-DoF mathematical model whose parameters are extracted by both measurement and 3D modeling of the real system components. The perturbative... 

Particulate air pollution is one of the top environmental health risks. Industrial processes like power generation from fossil fuels and steel and cement manufacturing release a huge amount of particles into the atmosphere. Moreover, internal combustion engines produce a considerable amount of particulate matter in populated areas. The usual way to overcome this risk is using air-cleaning devices such as filters. Filters are designed for specific purposes like removing aerosol particles, aerosol sampling and collecting valuable particles. Because of its diverse applications, filtration has become an active area of research and many kinds of filters are currently available. One type of... 

In this thesis, the behavior of cold-form steel (CFS) frames equipped with various configurations of steel sheathing and K-shaped braces is experimentally investigated. Low lateral resistance is the main deficiency of the CFS shear walls. Despite their advantages, such as being lightweight, ease of fabrication, and an environmentally friendly system, their lack of adequate lateral strength prevents engineers from widely using them, especially in areas with medium to high seismicity or in mid-rise buildings. In this regard, a total of seven full-scale specimens with different configurations of steel sheathing and k-braced, with and without cladding, were tested to investigate their seismic... 

On the average, ten thousand people die annually due to earthquakes. A UNESCO study gives damage losses amounting to ten billion dollars within the years 1926 to 1950 from earthquakes. These data shows the importance of earthquake issue that causes the scientists to pay special attention to this subject. In despite of significant improvements in many of scientific fields, earthquake is still remains as an unknown event without the possibility of predicting its time and location of occurrence. Because of that, a large effort has been paid for rehabilitation of structures to prevent the human loss and maintaining the necessary life safety. In this regard, various guidelines have been proposed... 

Speech enhancement in noisy environments improves the quality and intelligibility of speech and reduces communication fatigue. High performance speech enhancement models are based on Bayesian estimation models, requiring estimations of the parameters of the functions that describe the likelihood and the prior distributions of the signal and noise processes. Two Bayesian speech enhancement models which are used in this thesis are Bayesian-Kalman filter and Bayesian MAP estimation.In real time applications including VoIP, in addition to additive noise, packet loss or packet delays might also occur. In real time communications the receiver terminal replaces silence for the duration of lost... 

The leaching process is the first stage in the process of extracting uranium out of the ore. The leaching, based on the used material is divided into two main methods of acidic and alkali leaching. Each of these two techniques have their own pros and cones. It is notable that due to lower costs, and faster kinetics, the acid leaching is the first option of the mines unless the percentage of carbonates (and the other acid-soluble materials) in the ore are too high that makes this process uneconomical because of higher acid consumption. The kinetics of the acid leaching of the uranium depends on various parameters such as acid concentration, the particle size, exposure time and the temperature... 

Considering the fact that human capital is a crucial element in explaining the differences in income per capita and economic growth among countries, this research focuses on the effect of initial endowments of individuals on the process of human capital accumulation. One of the most important questions one can ask in this regard is whether individuals that are born in households with a low level of endowments, cannot develop their level of human capital due to a lack in the ability to obtain the factors required for their educational attainment. To answer this question, and considering the limitations of obtaining educational data, we aim to answer this question using district-level data.... 

In this project, we examine the stability or sustainability issue in unions, in other words we want to know whether integration in European Union is stable? Countries have positive attitude toward unions and being member in unions is at special priorities. The main reason for countires is improve economy and national Security.
The main question in this research is modeling European Union with Axiomatic Design Theory and analysis of sustainability based on this theory. This study has attempted to push Axiomatic Design Theroy in the new field of Systems Engineering and also it gives a new and differnet approach to stability.
 

Knowledge sharing as one of the most important knowledge management processes has been discussed in this research. The purpose of this study is investigating relationship between the Nonaka’s conditions for organizational Knowledge Creation and strengthening interpersonal Knowledge Sharing in the “Oil Industries Engineering and Construction Co. (OIEC)”. A quantitative questionnaire based servey was used to collect the required data and Structural Equation Modeling (SEM) to test the questions. The findings suggest that the “project intention”, ”personal autonomy”, “autonomy of project team” and “requisite variety” have impact on “attitude toward knowledge sharing”, and there is no significant... 

In this thesis, we will take a more profound study about what technology is and the relationship between technology development and society. We will discuss various theories such as the social construction of technology, the heterogeneous engineerings approach, the system approach, and the co-construction of society and technology. In this way, the relationship between economic and social systems and technological products is explained and based on this, an approach is proposed in relation to the ethical challenges in technology with a focus on social networks. The discussion is about the fact that due to the continuous use of technologies, a challenge may be raised in the technology... 

In this thesis, we will take a more profound study about what technology is and the relationship between technology development and society. We will discuss various theories such as the social construction of technology, the heterogeneous engineerings approach, the system approach, and the co-construction of society and technology. In this way, the relationship between economic and social systems and technological products is explained and based on this, an approach is proposed in relation to the ethical challenges in technology with a focus on social networks. The discussion is about the fact that due to the continuous use of technologies, a challenge may be raised in the technology... 

Does the direct involvement of social values in science, damage the reliability of scientific claims? Using recent debates in the relation between science and value, I will try to answer this question. Over the past few years, it has been shown that values can play a role in justifying scientific knowledge. People like Jeffrey and Betz try to take values out of science using methodological advice; while others, like Douglas, argue that values cannot and should not be excluded from science. If we accept the presence of values, there must be limits to their involvement, or we will fall to chaotic state. One of the concepts that can help us to regulate the behavior of values, is the reliability... 

Cultural and social problems in the modern age have motivated many thinkers to analyze modernity. Some of them have tried to solve these problems and, if possible, prevent their occurrence in the future. Proposed solutions are mostly dystopian, i.e. by being disappointed, they think the only possible way to overcome these problems is to annihilate modern civilization, or they pursue a passive approach; i.e. they have accepted the problems of modernity but only seek a way to mitigate its challenges. Among these, solutions which try to make use of the capacities of the modern civilization, especially emerging technologies, are really scarce. These approaches seek to realize (and make... 

Most of local thinkers ,who were influenced by Western philosophers of science, and have spoken about religious knowledge, have selected experimental science as standard science and Have tried to find a way trough cultural and other non-scientific channels of science to influence the field of human knowledge by religious teaching's .This expert's are generally opposed to positivist’s models of science, but because of the nature of the Western atmosphere that they breathe, consider the experimental science as the main model of knowledge and the experience as the main method of Acquisition of knowledge. Paya is also one of this thinkers who is influenced by Karl Popper's ideas about the... 

The emergence of lexical knowledge bases such as WordNet and FarsNet foregrounded the importance of semantic annotation of words in the areas of natural language processing and corpus linguistics. The methodology in these knowledge bases is based on semantic relations and dictionary definitions of the words in coverage. Another efficient way to perform semantic annotation is by semantically classifying the lexicon of a language in a taxonomy. In this research, we build a semantic annotation system for the semantic tagging of Persian texts. This system can be used for building tools and softwares for natural language processing in applications such as text summarization, plagiarism detection...