Sharif Digital Repository

Due to the growing rate of photovoltaic plants in power systems, in the future years this type of plant will have significant contribution in electrical energy generation. For this reason, the impact of photovoltaic plants on various aspects of power system operation should be investigated. In this research dynamic impacts of photovoltaic plants on small signal stability of power systems are analyzed. For this purpose, improved dynamic equivalent models are developed for large-scale photovoltaic plants, based on integration of the plant modules. It is shown that the usual assumption of ideal DC power supply at the input of plant inverter is inappropriate, and that the DC-DC converter and DC... 

Today, different cities in the world have hurried to consumers, natural resources, and producers of waste. Our cities are not excluded from this rule, especially metropolitan like Tehran, which accounted for only 12% of the country's land area, accounting for 15% of the volume of airborne contamination in the country. Considering the importance of the environmental pollution issue and the many researches done in this field, the present study attempts to investigate and analyze the application of renewable energy to reduce environmental pollution with an emphasis on the automotive industry. This is an applied research in terms of purpose. These types of researches are applicable because these... 

With the expansion of the use of information technology and public access to financial markets, the number of players in this field has increased and as a result, the nonlinear behavior of the market has become more complex than before. Due to this issue, investors need specific strategies to identify suitable assets for investment and also to determine the time of entry and exit to the stock market in order to make a profitable investment. Therefore, the purpose of this study is to form a stock portfolio as an asset and based on an integrated approach of fundamental and technical analysis using machine learning techniques. In this research, the stock data of Tehran Stock Exchange and OTC... 

The role of Technological Human Body is mainly overlooked in the Philosophy of Technology. However as result of diverse bodily technologies (somatechnologies) which are emergent everyday, for either enhancement, rehabilitation, or even recreational activities, the realtion between bodies and technologies are such entangled that no longer could anybody ignor it. Cyborg is an amalgamation of Human and Machine. The philosophical challenges that such an entity brings forth is immense; Agency, Intentionality, Subjectivity, Power relations, Ethics to mention but a few. In this study we try to investigate such issues through a phenomenological and feminist stance by examining Everyday cyborgs, i.e.... 

Some philosophers and thinkers have made serious criticisms of modern technology, considering it the cause of major problems. These critiques and problems have motivated some philosophers to think of alternatives for technology. Andrew Feenberg, one of the scholars seeking alternatives for technology, argues that the modern technical system is derived from the values of capitalism and serves a select few. As a diagnosis, Feenberg considers the capitalistic values to be the root of modern technological crises and as a prescription, he recommends a “democratic technological design system”. Feenberg has proposed no criteria for evaluating the values that could be incorporated into the... 

In today’s highly competitive world, the countries with strong economies are able to produce their products at a lower price, better quality and at the right time in the market, therefore, in the performance evaluation of economic of the organizations and project management, several factors are involved; the most important are: time, price, and product quality. In this dissertation, a new method for performance evaluation in the field of project management based on combining the concept of the golden triangle of the project and the techniques available in decision science is presented. At first, three major areas of the golden triangle namely time, cost, and quality are selected for... 

The long-lasting debate on the value-free ideal of science has cooled down in the past two decades. Many philosophers of science now believe that scientific activity, even in the theory-evaluation phase, cannot be done completely free of social and ethical values. Thus in recent years, science and values literature has been more specific and mostly focused on the role of values in different phases of scientific activity. One of the well-noted topics is the epistemic priority thesis, in which its proponents prioritize epistemic considerations in the evaluation of scientific theories, to preserve the objectivity of science. In contrast, several criticisms have been directed at this thesis. We... 

Social constructionism and metaphilosophy are two fields that seem incompatible and different from each other. One is the point of view that at least part of the basic truths of human life-world, which gives meaning and foundation of his personality, are things made by humans themselves; At the same time, the other considers himself responsible for discovering the original and absolute truths and draws a line against the relativism and constructivism of the fundamental principles of human society. "Philosophical progress" which is the central content of this article, on the one hand, has taken root in the field of metaphilosophy to understand its philosophical nature, and on the other hand,... 

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... 

Sustainable energy supply and preservation of the environment have become the main motivations to integrate more renewable energy sources in electrical networks. However, with an increasing penetration of renewable energy sources in the modern electrical grids, new challenging issues arise regarding the power system planning, operation, control and protection. An important technical issue is the difficulty in achieving the frequency stability of these systems, as the renewables are often operated at the maximum power point, resulting in less generation units that provide reserve power. Moreover, the rotational inertia of the system is reduced due to the decoupling of the renewable energy... 

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... 

What is meant by the scientific progress and how can it be explained? In response to this question, four distinct approaches—epistemic, semantic, problem-solving, and Noetic—have been presented. Each of these approaches defines the goal of science in a specific way: the epistemic approach considers the accumulation of scientific knowledge as the goal; the semantic approach views the goal as nearness to truth; the problem-solving approach sees the goal as solving more problems; and the Noetic approach sets the goal as increasing understanding. In this study, each approach is critically examined, and two central claims are made. The first claim asserts that to explain the scientific progress,... 

One of the most important applications of artificial intelligence, and especially deep learning is image captioning. Given an image, the task is to automatically produce a sentence, describing the image. Image captioning has several real world applications like helping the blind understanding the images, generating automatic captions for the social media, etc. In the past, several different methods for image captioning have been used, but after the emergence of deep learning, like many other areas, image captioning algorithms have been improved significantly. In this thesis, I talk about a specific method for image captioning, called ”Deep Compositional Captioning. In this method, at first... 

Statistics is an essential part of decision making and management in all organizations if the needed information is correct and updated. Due to lack of suitable information systems, it needs rework and spend extra time to gather information. Information Technology is used to summarize organizational information. It supports management of organization to make decision for strategic planning, tactical planning and operational programming by creation, storage, retrieve and distribute correct information to managers. For implementing these systems, there are many solutions. Selecting each one depends on conditions and potentials. Implementing integrated systems is expensive task therefore large... 

Rail equipment suppliers in the manufacturing realms of activity are obliged to comply by global standards in order to provide the requirement needs of the rail industries and the needs of customers. In this way, the standards would enhance the quality, safety and reliability of the railway industry. International Railway Industry Standard (IRIS), as an exclusively railway standard that is based on or a more refined of the ISO 9001 Quality Management Standard Policies, which adds in fact further layers to the ISO 9001 structure. The IRIS is the result of long term process in development of an international quality management standard for railway fleet. The objective of this thesis is to make... 

Given an element "H" in H^3 (X,Z), one can define the twisted K-group K(X,H). These groups have been appeared in physics and in particular in String Theory. As an explicit example, we study the twisted K-group of principle circle bundle E. An important notion related is the T-duality. We introduce (E,H), with E a principle circle bundle and H an element in H^3 (E,Z). Under certain circumstances we call (E,H) and (E,H)T-Dual. We study twisted K-theory of dual pair (E,H) and (E,H)  

Today the hydrocarbon materials rank in the list of requirements of the modern societies. The increased growth of the human population, their industrial economic activities, transportation etc. requires sufficient supplies of our resources. Therefore, the hydrocarbon resources need to be discovered and evaluated accurately. There are different methods that are used to measure underground hydrocarbon resources such as well logging. In this method, a measuring device is lowered into a well to evaluate several parameter of the surrounding soil. Nuclear well logging is a sub category of well logging that uses nuclear rays to do this measurement. This method has different types of sondes which... 

In this Thesis, a nuclear borehole logging tool has been designed and constructed for measuring the bulk density of a formation by the use of gamma rays. One of the main applications of this tool is obtaining of porosity. It also is useful in the detection of formations containing oil and gas. This tool consists of: a gamma ray source 60Co, a single gamma ray detector NaI(Tl), lead shield and electronic modules. The cylindrical sond is entered into a borehole and the surrounding formation is subjected to the emitted gamma rays from the source. The formation density can be determined from the measurement of the scattered photons reaching the detector from the formation. The purpose of the... 

Gamma-ray spectroscopy is the quantitative study of the energy spectra of gamma-ray sources. A gamma-ray spectrometer also determines the energies of the gamma-rays photons emitted by the source. A radioactive nucleus (radionuclide) commonly emits gamma rays in the energy range from a few keV to ~10 MeV, corresponding to the typical energy levels in nuclei with reasonably long lifetimes. Most radioactive sources produce gamma rays of various energies and intensities. When these emissions are collected and analyzed with a gamma-ray spectroscopy system, a gamma-ray energy spectrum can be produced. A detailed analysis of this spectrum is typically used to determine the identity and quantity of...