Slide 1Social Networks http://www.flairandsquare.com/archives/167Popular Social NetworksSocial Networks: More formal definitionSocial Network ExamplesHistorySocial Networks Basic QuestionsSlide 8Social Network ConceptsPractical issues: Boundaries and SamplesSocial Network Analysis of 9/11 Terrorists (www.orgnet.com)Social Network Analysis of 9/11 TerroristsSlide 13Slide 14Slide 15Slide 16Social Network Analysis of Steroid Usage in Baseball (www.orgnet.com)Knowledge Management ExamplesKnowledge Sharing in Organizations: Finding ExpertsKnowledge Sharing Network: Finding Experts (www.orgnet.com)Social Networks: Security and Privacy Issues: European Network and Information Security AgencySocial Networks: Security and Privacy Issues: Microsoft Recommendations http://www.microsoft.com/protect/yourself/personal/communities.mspxSlide 23OverviewIntroductionOur ApproachSocial NetworksSlide 28Threat Detection and Correlation AnalysisThe ExperimentSetupSlide 32Slide 33Slide 34Current ResultsIssues and DirectionsSocial Networking, Security and PrivacyDr. Bhavani ThuraisinghamApril 21, 20081-201/13/19 22:59 Social Networkshttp://www.flairandsquare.com/archives/1670A social network site allows people who share interests to build a ‘trusted’ network/ online community. A social network site will usually provide various ways for users to interact, such as IM (chat/ instant messaging), email, video sharing, file sharing, blogging, discussion groups, etc.0The main types of social networking sites have a ‘theme’, they allow users to connect through image or video collections online (like Flicker or You Tube) or music (like My Space, lastfm). Most contain libraries/ directories of some categories, such as former classmates, old work colleagues, and so on (like Face book, friends reunited, Linked in, etc). They provide a means to connect with friends (by allowing users to create a detailed profile page), and recommender systems linked to trust.1-301/13/19 22:59 Popular Social Networks0Face book - A social networking website. Initially the membership was restricted to students of Harvard University. It was originally based on what first-year students were given called the “face book” which was a way to get to know other students on campus. As of July 2007, there over 34 million active members worldwide. From September 2006 to September 2007 it increased its ranking from 60 to 6th most visited web site, and was the number one site for photos in the United States. 0Twitter- A free social networking and micro-blogging service that allows users to send “updates” (text-based posts, up to 140 characters long) via SMS, instant messaging, email, to the Twitter website, or an application/ widget within a space of your choice, like MySpace, Facebook, a blog, an RSS Aggregator/reader. 0My Space - A popular social networking website offering an interactive, user-submitted network of friends, personal profiles, blogs, groups, photos, music and videos internationally. According to AlexaInternet, MySpace is currently the world’s sixth most popular English-language website and the sixth most popular website in any language, and the third most popular website in the United States, though it has topped the chart on various weeks. As of September 7, 2007, there are over 200 million accounts.1-401/13/19 22:59 Social Networks: More formal definition0A structural approach to understanding social interaction. 0Networks consist of Actors and the Ties between them.0We represent social networks as graphs whose vertices are the actors and whose edges are the ties. 0Edges are usually weighted to show the strength of the tie.0In the simplest networks, an Actor is an individual person. 0A tie might be “is acquainted with”. Or it might represent the amount of email exchanged between persons A and B.1-501/13/19 22:59 Social Network Examples0Effects of urbanization on individual well-being0World political and economic system0Community elite decision-making0Social support, Group problem solving0Diffusion and adoption of innovations0Belief systems, Social influence0Markets, Sociology of science0Exchange and power0Email, Instant messaging, Newsgroups0Co-authorship, Citation, Co-citation0SocNet software, Friendster0Blogs and diaries, Blog quotes and links1-601/13/19 22:59 History0“Sociograms” were invented in 1933 by Moreno. 0In a sociogram, the actors are represented as points in a two-dimensional space. The location of each actor is significant. E.g. a “central actor” is plotted in the center, and others are placed in concentric rings according to “distance” from this actor. 0Actors are joined with lines representing ties, as in a social network. In other words a social network is a graph, and a sociogram is a particular 2D embedding of it. 0These days, sociograms are rarely used (most examples on the web are not sociograms at all, but networks). But methods like MDS (Multi-Dimensional Scaling) can be used to lay out Actors, given a vector of attributes about them. 0Social Networks were studied early by researchers in graph theory (Harary et al. 1950s). Some social network properties can be computed directly from the graph.0Others depend on an adjacency matrix representation (Actors index rows and columns of a matrix, matrix elements represent the tie strength between them).1-701/13/19 22:59 Social Networks Basic Questions0Balance: important in exchange networks0In a two-person network (dyad), exchange of goods, services and cash should be balanced. 0More generally, exchanges of “favors” or “support” are likely to be quite balanced. 0Role: what role does the actor perform in the network?0Role is defined in terms of Actors’ neighborhoods.0The neighborhood is the set of ties and actors connected directly to the current actor. 0Actors with similar or identical neighborhoods are assigned the same role. 0What is the related idea from semiotics?0Paradigm: interchangability. Actors with the same role areinterchangable in the network.1-801/13/19 22:59 Social Networks Basic Questions0Prestige: How important is the actor in the network? 0Related notions are status and centrality. 0Centrality reifies the notion of “peripheral vs. central participation” from communities of practice. 0Key notions of centrality were developed in the 1970’s, e.g. “eigenvalue centrality” by Bonacich.0Most of these measures were rediscovered as quality measures for web
View Full Document
Unlocking...