Sharif Digital Repository

Increasing demand for higher data rates and more reliable communications along with growing applications of multimedia networks in everyday life on one hand, and limited resources on the other, have given rise to researches investigating spectrum efficiency enhancement techniques, among which multiuser diversity has always been of considerable importance. This thesis is a study on utilization of multiuser diversity in wireless LANs via scheduling. Where throughput and Quality of Service (QoS) in communication networks are being investigated, it is mostly advantageous to describe the traffic behavior of resources by greedy or non-greedy models. So far, there are plenty of investigations on... 

Fair allocation of bandwidth between stations of a shared medium, is an important and challenging problem. It is even more challenging when there is no coordinator to arbitrate access to the medium and therefore, a distributed algorithm is needed to provide fairness. IEEE 802.11 DCF is the dominant distributed medium access control (MAC) protocol in a wireless LAN. However, DCF is not in general fair and suffers from short-term unfairness. In addition to that, it is desired to provide differentiated service for the stations of a LAN based on their demands. Since priority based protocols may lead to starvation of the low priority traffic, we are more interested in fair queuing. On the other... 

The 60 GHz high speed technology, is the interesting category in network world nowadays. In this study, we consider one of the 60 GHz technologies as it is called WiGig. WiGig works under IEEE802.11ad standard, one of the WLAN standards that works at 60 GHz frequency band. We have surveyed the total MAC and physical layer of this standard to find the way to enhance the MAC protocol. This MAC protocol is applying the CSMA/CA and TDMA methods to access the channel. We have applied the CSMA/CA in our thesis that is a contention based access method. We found that with this method our network is not fair. Since there are not any studies about the value of Fairness in this standard, we... 

In auction-based cloud investment environments, consumers desire the least possible cost and high satisfaction, while providers seek strategies to maximize profit and return on investment. In these environments designing an adequate resource allocation that can satisfy both consumers and providers is of utmost importance. Yet, most available models in resource allocation focus on providers’ needs and do not concern themselves with the consumers. Therefore the present study aims to present an efficient and optimum model for resource allocation problem that takes into account various factors, e.g. resource price, service quality, reputation and fairness, and is capable of satisfying all honest... 

While the action in society is at stake, it seems that, I merely do something in my personal sphere, but its consequences will not remain ultimately in my personal sphere. It goes beyond of my personal realm and obviously affects other persons and their choices. This claim is one of the most central claims of Rousseau’s philosophy of right. But if it is so, or in some more technical sense, it is the case that there is some mutual dependence between individuals in social life, then my sphere of freedom would not be merely mine. Consequently, a new question would be of some central importance: What is permissible for me, meanwhile I am living in state of society? Rousseau concludes in response... 

The debate over political philosophy has resurfaced five decades after the publication of John Rawls' famous book on the theory of justice. In that book, Rawls criticizes perfectionist states, And considers a state just that leaves the perfection and goodness of human beings to the citizens themselves. And the state can not be the final arbiter and interferor in the good and perfection of the citizens, and the state should never be one-sided in this conflict between the various opinions of the people about the good. Therefore, the state should only provide the means for citizens to be able to pursue their good deeds freely and equally, which is what Rawls calls the precedence of the right... 

The research examines the influence of Kant’s practical philosophy on John Rawls’ theory of justice, under the concept of “autonomy”. In the initial chapter, foundational concepts of the study such as “autonomy” and “duty” are discussed in detail within the context of prevailing views in moral philosophy, particularly deontological ethics. The overarching idea of this chapter is to establish a general conceptual framework for posing the main research question. The second chapter of this research specifically and independently elucidates Kant’s practical philosophy and clarifies his interpretation of the concept of “autonomy”. The aim of structuring this chapter is to demonstrate that...