Sharif Digital Repository

Network-on-Chip (NoC) is a promising on-chip communication paradigm which targets the scalability and predictability problems of the traditional on-chip mechanisms. However, it has been shown that, in future technologies (especially 22 nm technology), the power consumption of the current NoCs is about 10 times higher than the power budget can be devoted to them. Application-specific optimization is one of the most effective approaches to bridge the exiting gap between the current and the ideal NoC power consumptions. However, almost all existing application-specific customization methods try to customize NoCs for... 

Delay Tolerant Networks are a variation of Mobile Ad Hoc Networks, in which low density of nodes in the network area results in global disconnectivity among the nodes. In these networks, communication of data throughout the networks takes place by the means of mobility; nodes store data packets and carry them around the network and forward them to other nodes they encounter along the way. In these situations, a proper selection of data to be exchanged between nodes has a great impact on the quality of data distribution in the whole networks. There is a common assumption among most of the techniques presented in category of Delay Tolerant Networks. They assume the probability of more than two... 

Project in brief: reconfiguring the network according to application which has been run on the network is one of the ways to improve using resources in the network-on-chip. There is a hierarchical cluster based NOC. In this network, nodes are going to partition into clusters. Every cluster’s node can have its own configuration and the configuration of inside of each cluster is unchangeable however the relationship between clusters is configurable. This ability is made by some switches which are located between clusters and they can change the way that clusters are related. The number of nodes which is inside the cluster are cluster size and the number of switches between two adjacent... 

In the recent years, the role of combinatorics and graph theory have grown in the progress of computer sciences. For instance, the circulant graphs have applications in design of interconnection networks and the graphs with integer eigenvalues are applied in modelling quantum spin networks supporting the perfect state transfer. The circulant graphs with integer eigenvalues also found applications in molecular graph energy. In 2006, it was shown that an n-vertex circulant graph G has integer eigenvalues if G=Cay(Zn; T ) or G= Cay(Zn; T)∪Cay(Zn;U(Zn)), where T Z(Zn). The Cayley graph Cay(Zn;U(Zn)) is known as the unitary Cayley graph. Fuchs defined the unitary Cayely graph of a commutative... 

Due to their enormous CO/〖NO〗_x removal capabilitiy, catalytic converters are deemed as indispensable parts of modern vehicles. These converters are comprised of a bundle of parallel tubes which their internal walls are wash-coated with a catalyst such as platinum or rhodium. The typical geometry for the tubes’ cross-section is honeycomb. In this project, the effect of tube cross-section geometry on CO/〖NO〗_x removal performance of catalytic converters is studied. In this respect, a three-dimensional model consisted of incompressible flow, advection-diffusion, and surface reaction was developed. Candidate geometries were triangle, square, honeycomb, and circle. The results show that as the... 

In recent years, significant interest has been attracted towards using directional antennae in wireless and sensor networks due to it’s decreased energy consumption, increased security and decreased radio wave overlapping. Substituting omni-directional antennae with directional antennae should be performed in a way that not only guarantees connectivity, but also minimizes radius and latency in network nodes. The problem is not polynomially solvable in general and effort has been made in recent years to present approximation algorithms to solve this problem. The approximation algorithms have been made possible using unit disk
graphs, Euclidean minimum spanning trees, grouping of... 

Real-time (RT) communication support is a critical requirement for many complex embedded applications which are currently targeted to Network-on-chip (NoC) platforms. Average Delay and Average Bandwidth are historically the popular metrics used to evaluate the performance of an on-chip network. For RT communication, guaranteeing Minimum Delay and Maximum Bandwidth (performance bounds) which are known as the metrics for Quality-of-Service (QoS) have been at great importance during recent years. Networks-on-chip are classified to Best-Effort (BE) and Guaranteed-Service (GS) networks. Packets are processed without any precedence in BE networks, while there are special hardware and controlling... 

In this thesis all the information about different techniques and methods used in Local Area Network (LAN) are described and organized as follows:
Chapter 1: The network properties are described including Network definitions and different types of LAN and their relative applications
Chapter 2 :Different techniques and protocols of data transfer and switching methods are being described and compared.
Chapter 3 : Network technology consists of different topologies for physical connections and various transfer Medias are covered.
Chapter 4 :All network protocols are described including different methods of DATA access in LOOP, RING and BUS topologies and the ISO and IEEE... 

In recent years, flash-based Solid State Drives (SSDs), because of their lower power consumption, higher throughput, and resistance against physical damages compared to Hard Disk Drives (HDDs) have confronted ever increasing usage in data center, cloud applications, and enterprise servers. Recently, advantages of using interconnection networks between SSD controller and NAND Flash chips for transferring data and commands have been shown. Interconnection network intrinsically provides many advantages such as maintaining the signal integrity at high frequencies, pipelining support, sharing the communication resources, eliminating communication bottlenecks, and reducing power consumption. The... 

We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM).We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon... 

Software defined networks are developed to provide programmability and a centralized view in networks by decoupling control plane from data plane. Software defined networks are now well received,and these networks are evolving every day. This is while more attention has been paid to widen the application of these networks and eliminating the shortcomings in their performance. On the other hand, in very large networks, the issue of efficiency and processing speed is of great importance. However, performance in these networks is not satisfactory, especially in single controller based SDN due to the complex processing of packets in a unique controller. Security needs are also of great...