Sharif Digital Repository

In the recent years, emerging vehicular ad hoc networks offer a wide variety of applications, including safety, convenience and entertainment. One of the beneficial applications in these fields is video streaming. However, according to the features like high mobility and loss of links, establishment of video streaming which requires stringent Quality of Service is a daunting task. In this thesis, the goal is introducing approaches in two levels, one for resilient video coding and the other one for network routing. For resilient video coding, the concentration is on the scalable video coding, which supports various applications for users with different requirements. The introduced approach... 

Energy Harvesting is one of the techniques which can be utilized in Green Communications and increase the wireless networks lifetime. In an EH system, each resource is supplied with the energy harvested from the environment. When we confront with a situation that the users of one channel want to increase their rates and this action negatively affects the other user’s rates, the user’s cooperation problem for obtaining a fair rate will be created. In this study, at first we consider a Multiple Access Channel and we assume that the energy resources of transmitters are harvested according to a known probability. In addition, we assume that the transmitters do not know the instantaneous amount... 

Feyarabend’s philosophy of science is against method and rule such that he believes that “anything goes”. However, he sometimes applies the term “progress”. Reviewing his publications shows that from his point of view, progress is qualitative and relative. So, unlike other philosophers of science Feyarabend ignores the clarification of the concept; subsequently, his applications of the term “progress” are somewhat ambiguous. However, by studying his philosophy, one may realize what should be done to achieve progress in any sense. The affirmative aspect of Feyerabend’s philosophy, while highlights the social and ethical elements, considering his humanitarian outlook as well as his special... 

In this thesis, I study the concept of social ethics from a modern point of view. What I call modernity, is the fundamental philosophical revolution happened in the sixteenth and seventeenth centuries in Europe, this period is called “Enlightenment”, what I assume is from Machiavelli to Kant. One of the most important philosophers belongs to this enlightenment period is Thomas Hobbes, a Scottish philosopher whose main book “Leviathan” is well-known as the basis of the modern politics. Modern politics makes sense against classical one, founded by Aristotle in a book mentioned under the same title. What Hobbes describes as society based on public interests etc. is in a different point of view... 

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... 

It has been five years since the new education system was started, according to which fundamental changes have been applied to school text books. The mentioned changes in the text books are based on “the fundamental transformation document” and “Iran’s national educational curriculum”. In “Iran’s national educational curriculum”, eleven fields concerning pedagogy and learning are explicitly mentioned; one of these eleven fields is “training and learning work and technology”. One of the merits which has been stressed in this field, is “technological thinking”. Nowadays, methods of extending and reinforcing the technological thinking have come to be the subject of investigations in many... 

Client applications are often developed with the help of software frameworks in order to reduce the development costs and to increase the software quality. However, frameworks may evolve to add new features or to fix bugs, and thus, their APIs may change at the same time. Nevertheless, these API changes can cause the client applications to not work properly. New frameworks typically use the deprecation mechanism to reduce this effect, but their documents often do not provide sufficient information. Consequently, deprecated APIs usages remain unresolved in client applications. To tackle this issue, we introduce ARFES (Automated Recommender of Framework Evolution Solutions) that provides... 

Religious science, its nature, possibility, and the mechanism of achievement have come to the fore in recent years. In this thesis, Javadi Amoli’s and Golshani’s theories are compared in this respect. Javadi Amoli begins by situating the reason, and certain knowledge as its product, in the architecture of religious knowledge. Since this kind of knowledge unveils divine action, Amoli counts it as already divine in nature. Therefore, there would be no conflict between science and religion in principle, unless atheist scientists insist on drawing non-empirical conclusions from sciences. Other conflicts too are superficial and resolvable. Amoli sees the fault of current sciences, which should be... 

The purpose of writing this thesis is to arrive at the concept of civilization. And in this process, using the constructive perception. My approach in constructive perception is different with approach of Allameh tabatabaei in constructive perception. In first chapter defining constructive perception as the perception that mind by analogy between two consepts makes the non-real relations and attributes it deliberated to the reality (the parties). Meanwhile, should have been constructive perception is the intermediary that stimulation our sense abut reality. These feelings can be tenderness or hatred or fear and hope and ... . In the second chapter we will show that the use of technology... 

With the expansion of industry, steel to copper joints applications in heat and electricity transmission equipment have increased. Steel has better mechanical properties and weldability and lower prices, and copper has better thermal and electrical conductivity properties; because of that, this dissimilar joint fits needs such as cost reduction and high efficiency. This study has parametrically investigated the feasibility of dissimilar welding of these metals using the resistance spot welding process.This study conducts three phases. In the first phase, low carbon steel and copper were directly welded, and it was found that the mechanical properties of the joint were affected by physical... 

In this research, synthesis, structural and theoretical studies of new rhenium (I) tricarbonyl complexes with general formula, [Re(CO)3(NN)X] in which NN´ is chelating bidentate diimine ligand and X = Perrhenate, NO2 and ONO ligands were studied. The synthesized complexes were characterized by 1H-NMR, FT-IR and ESI-mass spectroscopic methods and their solid state structures were determined by X-ray diffraction analysis. Crystal structure determination by single-crystal X-ray diffraction allows us to fully examine the intramolecular and intermolecular interactions. The energy of different n → π* interactions also was investigated. Since three carbonyl groups are present in these complexes, we... 

Facility location decisions play a prominent role in strategic planning of many firms, companies and governmental organizations. Since in many real-world facility location problems, the data are subject to uncertainty, in this thesis, we consider the P-center problem under uncertainty of demand nodes. Using Bertsimas and Sim approach, we modeled the problem as a linear optimization model. Furthermore, we develop a tabu search algorithm to solve the problem. Finally we designed some experiments to adjust the parameters of tabu search algorithm. We presented the numerical result accordingly  

One of the most important methods for recycling of spent Li-ion batteries is acid leaching that various parameters affect it. In this work, influences of effective parameters on the percent of cobalt and lithium recovery with application of design of experiments (response surface methodology-central composite) were investigated and then cobalt nano oxide as the by-product synthesized by pulsing lectrolysis. In the first Phase, effects of parameters such as sulfuric acid oncentration: 2-6 molar, hydrogen peroxide volume percent: 5-10%, S/L ratio: 20-50 g/L and temperature: 50-80°C on cobalt and lithium recovery were investigated and finally an adequate model presented. For all experiments,... 

In this study, a mathematical model for health-care facility location in two level and multi-services has been described. The facilities has two levels of clinic and hospital that has inclusive hierarchy property. In clinics, only outpatient services delivered. But, in hospitals in addition to handle outpatient services, inpatient services and emergency services are provided. In this research, we practice on queuing theory in order to consider the serious uncertainties in the health service, for instance, random demand and random service time, and by the help of which the criteria for considering the service level is calculated. Then by using applicable change variable and service level...