Sharif Digital Repository

In this thesis, the simulation of HEMT for high frequency applications has been explored. It has been tried to examine the changes such as: gate recess, T-shaped gate, changing the channel length and doping of buffer layer on the performance of the proposed device. Simulation results show that the best way to improve the device performance, in particular its cut-off frequency, is increase in buffer layer doping density. Because it significantly increase the saturation current, electron mobility inside the channel, the transconductance and the cut-off frequency. If we need to lower the noise, the T-shaped gate can also be used. Also, by change in doping of donor layer, amount of 1017 cm-3 is... 

The multilayer coating (Zn-Ni)1/(Zn-Ni)2 is deposited from a single bath with a zincate-sulfate compound and by changing the current density. The effect of current density and the number of layers on the chemical composition, surface morphology, roughness, phase structure, and corrosion resistance of multilayer coatings respectively using atomic absorption spectroscopy, FE-SEM microscope, roughness tests, X-ray analysis, and electrochemical techniques such as Tafel polarization and impedance was investigated and compared with single-layer coatings. Because the amount of nickel in the composition of the coatings is less than 27%, in all the studied currents, the deposition is anomalous. The... 

Nowadays population growth, people housing demand and urbanization tendency has increased the land and house prices. So the constructers tend to build apartments. Time consuming and heavy costs of building and renovation has made the owners to rebuild the damages of their houses in case of an accident. Time and cost are the main factors in construction which includes rebuilding. Buildings and especially apartments renovation is expensive and prolonged. So the rebuilding tendency has been noted more than ever. In this study it has been tried to control costs and time by efficient management to save the rebuilding time and money. Two kinds of questionnaire has been applied to study different... 

With the recent considerable developments in the Internet of Things (IoT), billions of resource-constrained devices are interconnected through the internet. Monitoring this huge number of IoT devices that are heterogeneous in terms of underlying communication protocols and data format is challenging. The majority of existing IoT device monitoring solutions heavily rely on centralized architectures. Since using centralized architectures comes at the expense of trusting an authority, it has several inherent drawbacks, including vulnerability to security attacks, lack of data privacy, and unauthorized data manipulation. Hence, a new decentralized approach is crucial to remedy these drawbacks.... 

In Naming and Necessity and Identity and Necessity, Kripke convinced many that there are necessary propositions which are knowable only a posteriori. Kripke’s examples of these propositions can be placed into three categories: 1) Some mathematical propositions like Goldbach’s conjecture (the conjecture that every even integer greater than 2 can be expressed as the sum of two primes) 2) Scientific truths like “Water is H2O”, “Gold has the atomic number 79”, etc. 3) Identity statements flanked on both sides with proper names; like “Hesperus is Phosphorus”, “Cicero is Tully” and the like (in the rest of this article, these three categories will be called, respectively, the first, the second and... 

In his Mind, Brain and Free Will, Swinburne introduces a new argument for substance dualism based on the synchronic unity of humans’ conscious experiences. He argues that the human body cannot be the substance of such a synchronic unity, and that this coexperiencing property, which is a mental property, is the essential property of the human substance: hence our substance is a mental substance. After providing a careful explanation of Swinburne’s subtle argument, I first try to demonstrate that it is metaphysically possible that the brain itself could instantiate such a synchronic unity without the need to presume another substance. Then I shall argue that it is unclear how to infer the... 

This dissertation consists of three chapters. In the first chapter, a description of formation of Darwin's theory of Evolution is expressed. After that, the process of formation of modern theory of Evolution, along with an explanation of the theory of evolution and the evidence for it was mentioned. In the second season, which is responsible for the scientific study of the theory, at some point the evidence of this theory has been reviewed. After that, some of the challenges raised against this theory have been studied. The major scientific challenges described in this chapter is based on recent advances made in biology, based on that, the mechanism of theory can’t explain the complex... 

Wilfrid Stalker Sellars (1912-1989) is an analytic philosopher whose philosophy is famous for being deep, systematic and extremely influential and notorious for being difficult to read. Although he has many original and interconnected ideas in different branches of philosophy- including metaphysics, epistemology, philosophy of mind, ethics, philosophy of language and meta-philosophy- the place of science in his system is completely indispensable. In his meta-philosophy, Sellars defines his philosophical project as an attempt to reconcile two distinct world-views of humanity in the modern word; scientific image and manifest image. Approaching Sellars’ philosophy by placing science at the... 

Michael Zimmerman in his book Living with Uncertainty has objected to two views of moral obligation, namely objective and subjective view. Two overcome these problems he suggests a third view which he calls prospective view and tells us that our moral obligation is determined by the prospection that each of our choices give us. In this thesis first I review Zimmerman’s objections to objective and subjective view. Then I try to suggest a solution for the objective view  

Technological capabilities as one of the growth’s aspects in developing countries have gained focus for research in last years. This study attempt to analyze the pattern of technological capabilities in four different sectors including Optic, Aerospace, Pharmaceutical and Biotechnology. In each sectors four Iranian companies as the case studies are selected. After deep interviews with key people in each company, required data is gathered. Data in each company is analyzed. The results of analysis for companies in one sector are gathered for analyzing each sector. In order to evaluate technological capabilities, the time required to improve, lead-lag relationship for gaining higher levels of... 

The relationship between art and philosophy has been disputed for a long time and its history goes back to the ancient Greece. The dominant literary form at that time was poetry or tragedy, which are the first side of this relationship. On the other side was philosophical ethics. Plato and Aristotle are the main protagonists in this quarrel, which is known as the "Ancient Quarrel". I will first examine this quarrel and follow its different forms in the modern era, in which Hegel plays a prominent role by proposing the "end of art" thesis. By examining the criticisms made to this thesis, I will make clear the context in which the contemporary defenses that I explained in the following... 

One of the important issues in the philosophy of mind is the challange about the content of mental states, how the mind can refer to the world. To explain this special relationship that is not observed in the physical world, various mental models have been implemented, one of which is the connectionism model. Connectionist networks are based on the idea of biological neural networks, and the main concern of connectionism is modeling the brain and implementing human mind characteristics. The connectionist model was proposed by emphasizing the necessity of linking symbols with their original content and meaning. In this model, data representation is done in a holistic way and based on network... 

One of the important problems in the history of philosophy of Mind &Science is to respond this question: whether our observations which are the basics of our experiences are theory laden or not? theory-ladenness of observation thesis has been endorsed by Duhem and hansen and thomas kuhn,generally theory-ladensess of observation devide in two concepts, firstly it means the affection of on the observable terms secondly it relates to the affection of theories on our perception and phenomenology of experience. fodor claims that theories has nothing to do with our observation and churchland claims vice versa, both of these philosophers mention their own reasons and in this thesis we are looking... 

After Hume’s skeptical argument on the concept of causality and establishing the regularity theory of causation by him, it seemed that the regularity theory might not respond to irrelevance problems and spurious regularities. In the second half of the twentieth century, attempts were made, e.g. Hans Reichenbach's proposal of the “common cause principle,” for solving the problems of regularity theory which resulted in probabilistic approach to causal relationships. The importance of the common cause principle is that it has inspired the “Causal Markov Condition” which is the most fundamental condition for causal networks. The causal Markov condition states that a variable X is... 

When we talk about something being normative, it means that there are do’s and don’ts specific to that thing. When we say that language is normative, it means that it is governed by do's and don'ts and we cannot use linguistic structures arbitrarily. In other words, we have justifiable modes of linguistic use that failing to accord with them will distort the meaning of the propositions in the language. In the field of ethics, it may be easier to comprehend the concept of normativity. We all are in touch with ethics and ethical propositions in our daily lives. Beyond this bond, it seems that there is a kind of necessity for us. It seems that because of this necessity, acting in accordance... 

This Thesis identifies the pattern of technological learning in developing complex products systems (CoPS). The experiences of Iran in missile development in the defense industry has been studied to explain the learning process in attaining indigenous technological capability. The case study of TOW missile development including international technology transfers has been explored to investigate the technological learning patterns. The role of policy initiatives had excessive importance through technological learning in the case study  

The debate over the nature of perceptual states has been a significant part of the literature of philosophy of the mind during the past two decades. John Campbell's philosophical works on metaphysics and epistemology of sensory perception, according to many of his followers and critics, are among the most coherent contemporary philosophical works with recent advances in cognitive science. His research on the relationship between attention, reference, knowledge and spatial representations is to a large extent supported by scientific ideas in empirical psychology, and it can be said that most of his work is devoted to analyzing and solving the theoretical complexities deriving from empirical...