Mojtaba Torkjazi

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This paper presents Respondent-Driven Sampling (RDS) as a promising technique to derive unbiased estimates of node properties in unstructured overlay networks such as Gnutella. Using RDS and a previously proposed technique, namely Metropolized Random Walk (MRW) sampling, we examine the efficiency of estimating node properties in unstructured overlays and(More)
In this section, we examine how the connectivity structure of the graph affects the efficiency of the RDS and MRW sampling techniques. Toward this end, we simulate both RDS and MRW techniques over several types of synthetic graph structures as well as one real graph. Note that we do not consider any of the synthetic graphs to be appropriate models of actual(More)
While some empirical studies on Online Social Networks (OSNs) have examined the growth of these systems, little is known about the patterns of decline in user population or user activity (in terms of visiting their OSN account) in large OSNs, mainly because capturing the required information is challenging. In this paper, we examine the evolution of user(More)
Online Social Networks (OSNs) provide a unique opportunity for researchers to study how a combination of technological, economical, and social forces have been conspiring to provide a service that has attracted the largest user population in the history of the Internet. With more than half a billion of users and counting, OSNs have the potential to impact(More)
While the size of popular online social networks such as MySpace and Twitter has been reported to be in the tens or hundreds of millions of users (and growing), little is known about the fraction of users who have either deleted or abandoned their accounts. Therefore, the growth of an OSN's overall user population and, more important, its population of(More)
During recent years, Online Social Networks (OSNs) have evolved in many ways and attracted millions of users. The dramatic increase in the popularity of OSNs has encouraged network researchers to examine their connectivity structure. The majority of empirical studies for characterizing OSN connectivity graphs have analyzed snapshots of the system taken in(More)
Based on my setting for the Autofill Columns of NodeXL (shown in the caption of Figure 1), we can response to our research questions. Those vertices that are large and light colored are potential spammers because they send out many messages and don’t receive any. In contrast, those that are small and dark may be unresponsive recipients since they receive(More)
Here in this paper, efficient privacy preservation over Mobile Social Networks is implemented to secure attacks over Mobile Social Networks. The Existing methodology implemented for the Friending Mobile Social Networks is efficient which provides an efficient computation of Data and privacy from unauthorized users. Here an efficient Decision Tree based(More)
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