75 research outputs found
Using Spectral Radius Ratio for Node Degree to Analyze the Evolution of Scale Free Networks and Small World Networks
In this paper, we show the evaluation of the spectral radius for node degree
as the basis to analyze the variation in the node degrees during the evolution
of scale-free networks and small-world networks. Spectral radius is the
principal eigenvalue of the adjacency matrix of a network graph and spectral
radius ratio for node degree is the ratio of the spectral radius and the
average node degree. We observe a very high positive correlation between the
spectral radius ratio for node degree and the coefficient of variation of node
degree (ratio of the standard deviation of node degree and average node
degree). We show how the spectral radius ratio for node degree can be used as
the basis to tune the operating parameters of the evolution models for
scale-free networks and small-world networks as well as evaluate the impact of
the number of links added per node introduced during the evolution of a
scale-free network and evaluate the impact of the probability of rewiring
during the evolution of a small-world network from a regular network.Comment: 8 pages, 8 figures, Second International Conference on Computer
Science and Information Technology, (COSIT-2015), Geneva, Switzerland, March
21-22, 201
Virtual Machines and Networks - Installation, Performance Study, Advantages and Virtualization Options
The interest in virtualization has been growing rapidly in the IT industry
because of inherent benefits like better resource utilization and ease of
system manageability. The experimentation and use of virtualization as well as
the simultaneous deployment of virtual software are increasingly getting
popular and in use by educational institutions for research and teaching. This
paper stresses on the potential advantages associated with virtualization and
the use of virtual machines for scenarios, which cannot be easily implemented
and/or studied in a traditional academic network environment, but need to be
explored and experimented by students to meet the raising needs and
knowledge-base demanded by the IT industry. In this context, we discuss various
aspects of virtualization - starting from the working principle of virtual
machines, installation procedure for a virtual guest operating system on a
physical host operating system, virtualization options and a performance study
measuring the throughput obtained on a network of virtual machines and physical
host machines. In addition, the paper extensively evaluates the use of virtual
machines and virtual networks in an academic environment and also specifically
discusses sample projects on network security, which may not be feasible enough
to be conducted in a physical network of personal computers; but could be
conducted only using virtual machines
Core-Intermediate-Peripheral Index: Factor Analysis of Neighborhood and Shortest Paths-based Centrality Metrics
We perform factor analysis on the raw data of the four major neighborhood and
shortest paths-based centrality metrics (Degree, Eigenvector, Betweeenness and
Closeness) and propose a novel quantitative measure called the
Core-Intermediate-Peripheral (CIP) Index to capture the extent with which a
node could play the role of a core node (nodes at the center of a network with
larger values for any centrality metric) vis-a-vis a peripheral node (nodes
that exist at the periphery of a network with lower values for any centrality
metric). We conduct factor analysis (varimax-based rotation of the
Eigenvectors) on the transpose matrix of the raw centrality metrics dataset,
with the node ids as features, under the hypothesis that there are two factors
(core and peripheral) that drive the values incurred by the nodes with respect
to the centrality metrics. We test our approach on a diverse suite of 12
complex real-world networks.Comment: 10 pages, 5 figure
A Survey on the Communication Protocols and Security in Cognitive Radio Networks
A cognitive radio (CR) is a radio that can change its transmission parameters based on the perceived availability of the spectrum bands in its operating environment. CRs support dynamic spectrum access and can facilitate a secondary unlicensed user to efficiently utilize the available underutilized spectrum allocated to the primary licensed users. A cognitive radio network (CRN) is composed of both the secondary users with CR-enabled radios and the primary users whose radios need not be CR-enabled. Most of the active research conducted in the area of CRNs has been so far focused on spectrum sensing, allocation and sharing. There is no comprehensive review paper available on the strategies for medium access control (MAC), routing and transport layer protocols, and the appropriate representative solutions for CRNs. In this paper, we provide an exhaustive analysis of the various techniques/mechanisms that have been proposed in the literature for communication protocols (at the MAC, routing and transport layers), in the context of a CRN, as well as discuss in detail several security attacks that could be launched on CRNs and the countermeasure solutions that have been proposed to avoid or mitigate them. This paper would serve as a good comprehensive review and analysis of the strategies for MAC, routing and transport protocols and security issues for CRNs as well as would lay a strong foundation for someone to further delve onto any particular aspect in greater depth
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