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Limiting the Spread of Misinformation in Social Networks
"... In this work, we study the notion of competing campaigns in a social network. By modeling the spread of influence in the presence of competing campaigns, we provide necessary tools for applications such as emergency response where the goal is to limit the spread of misinformation. We study the probl ..."
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In this work, we study the notion of competing campaigns in a social network. By modeling the spread of influence in the presence of competing campaigns, we provide necessary tools for applications such as emergency response where the goal is to limit the spread of misinformation. We study the problem of influence limitation where a “bad ” campaign starts propagating from a certain node in the network and use the notion of limiting campaigns to counteract the effect of misinformation. The problem can be summarized as identifying a subset of individuals that need to be convinced to adopt the competing (or “good”) campaign so as to minimize the number of people that adopt the “bad ” campaign at the end of both propagation processes. We show that this optimization problem is NPhard and provide approximation guarantees for a greedy solution for various definitions of this problem by proving that they are submodular. Although the greedy algorithm is a polynomial time algorithm, for today’s large scale social networks even this solution is computationally very expensive. Therefore, we study the performance of the degree centrality heuristic as well as other heuristics that have implications on our specific problem. The experiments on a number of closeknit regional networks obtained from the Facebook social network show that in most cases inexpensive heuristics do in fact compare well with the greedy approach.
When Information Improves Information Security
, 2009
"... We investigate a mixed economy of an individual rational expert and several naı̈ve nearsighted agents in the context of security decision making. Agents select between three canonical security actions to navigate the complex security risks of weakestlink, best shot and total effort interdependenci ..."
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Cited by 15 (7 self)
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We investigate a mixed economy of an individual rational expert and several naı̈ve nearsighted agents in the context of security decision making. Agents select between three canonical security actions to navigate the complex security risks of weakestlink, best shot and total effort interdependencies. We further study the impact of two information conditions on agents ’ choices. We provide a detailed overview of a methodology to effectively determine and compare strategies and payoffs between the different regimes. To analyze the impact of the different information conditions we propose a new formalization. We define the price of uncertainty as the ratio of the expected payoff in the complete information environment over the payoff in the incomplete information environment.
Better Vaccination Strategies for Better People
"... In this paper, we study the vaccination of graphs against the outbreak of infectious diseases, in the following natural model generalizing a model by Aspnes et al.: An infectious disease breaks out at a random node of the graph and propagates along the edges of the graph. Vaccinated nodes cannot be ..."
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In this paper, we study the vaccination of graphs against the outbreak of infectious diseases, in the following natural model generalizing a model by Aspnes et al.: An infectious disease breaks out at a random node of the graph and propagates along the edges of the graph. Vaccinated nodes cannot be infected, nor pass on the infection, whereas all other nodes do. The decisions on which nodes get vaccinated must be made before the random outbreak location is known. There is a cost associated with vaccination and a different cost with getting infected. In this model, we provide two results. First, we improve the approximation guarantee for finding the best vaccination strategy from O(log 1.5 n) to O(log z) (where z is the support size of the outbreak distribution), by rounding a natural linear program with regiongrowing techniques. Second, we analyze the impact of autonomy on the part of the nodes: while a benevolent authority may suggest which nodes should be vaccinated, nodes may opt out after being chosen. We analyze the “Price of Opting Out ” in this sense under partially altruistic behavior. Individuals base their decisions on their own cost and the societal cost, the latter scaled by some factor β. If the altruism parameter is β = 0, it is known that the Price of Anarchy and Price of Stability can be Θ(n). We show that with positive altruism, Nash Equilibria may not exist, but the Price of Opting Out is at most 1/β (whereas the Price of Anarchy can remain at Θ(n)).
The Price of Uncertainty in Security Games
, 2009
"... In the realm of information security, lack of information about other users’ incentives in a network can lead to inefficient security choices and reductions in individuals’ payoffs. We propose, contrast and compare three metrics for measuring the price of uncertainty due to the departure from the pa ..."
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Cited by 15 (3 self)
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In the realm of information security, lack of information about other users’ incentives in a network can lead to inefficient security choices and reductions in individuals’ payoffs. We propose, contrast and compare three metrics for measuring the price of uncertainty due to the departure from the payoffoptimal security outcomes under complete information. Per the analogy with other efficiency metrics, such as the price of anarchy, we define the price of uncertainty as the maximum discrepancy in expected payoff in a complete information environment versus the payoff in an incomplete information environment. We consider difference, payoffratio, and costratio metrics as canonical nontrivial measurements of the price of uncertainty. We conduct an algebraic, numerical, and graphical analysis of these metrics applied to different wellstudied security scenarios proposed in prior work (i.e., best shot, weakestlink, and total effort). In these scenarios, we study how a fully rational expert agent could utilize the metrics to decide whether to gather information about the economic incentives of multiple nearsighted and naïve agents. We find substantial differences between the various metrics and evaluate the appropriateness for security choices
A Survey of Interdependent Security Games
, 2012
"... Interdependence of information systems is a fundamental property that shapes the problems in information security. The risks faced by system operators and users is not only determined by their own security posture, but is heavily affected by the securityrelated decisions of other connected systems. ..."
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Cited by 9 (5 self)
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Interdependence of information systems is a fundamental property that shapes the problems in information security. The risks faced by system operators and users is not only determined by their own security posture, but is heavily affected by the securityrelated decisions of other connected systems. Therefore, defending networked systems relies on the correlated action of the system operators or users. In this survey, we summarize gametheoretic interdependence models, characterize the emerging security inefficiencies and present solution methods. Our goal is to distill the main insights from the stateoftheart and to identify the areas that need more attention from the research community. 1
Competing Memes Propagation on Networks: A Network Science Perspective
"... Abstract — In this paper, we study the intertwined propagation of two competing “memes ” (or data, rumors, etc.) in a composite network. Within the constraints of this scenario, we ask two key questions: (a) which meme will prevail? and (b) can one influence the outcome of the propagations? Our mode ..."
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Abstract — In this paper, we study the intertwined propagation of two competing “memes ” (or data, rumors, etc.) in a composite network. Within the constraints of this scenario, we ask two key questions: (a) which meme will prevail? and (b) can one influence the outcome of the propagations? Our model is underpinned by two key concepts, a structural graph model (composite network) and a viral propagation model (SI1I2S). Using this framework, we formulate a nonlinear dynamic system and perform an eigenvalue analysis to identify the tipping point of the epidemic behavior. Based on insights gained from this analysis, we demonstrate an effective and accurate prediction method to determine viral dominance, which we call the EigenPredictor. Next, using a combination of synthetic and real composite networks, we evaluate the effectiveness of various viral suppression techniques by either a) concurrently suppressing both memes or b) unilaterally suppressing a single meme while leaving the other relatively unaffected.
The Price of Civil Society
 In Proc. 7th International Workshop on Internet and Network Economics
, 2011
"... Abstract. Most work in algorithmic game theory assumes that players ignore costs incurred by their fellow players. In this paper, we consider superimposing a social network over a game, where players are concerned with minimizing not only their own costs, but also the costs of their neighbors in th ..."
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Cited by 7 (0 self)
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Abstract. Most work in algorithmic game theory assumes that players ignore costs incurred by their fellow players. In this paper, we consider superimposing a social network over a game, where players are concerned with minimizing not only their own costs, but also the costs of their neighbors in the network. We aim to understand how properties of the underlying game are affected by this alteration to the standard model. The price of civil society denotes the ratio of the social cost of the worst Nash equilibrium when each player cares about both herself and her friends, relative to the worst Nash under standard selfish play. We initiate the study of the price of civil society in the context of a simple class of games. Counterintuitively, we show that when players become less selfish (optimizing over both themselves and their friends), the resulting outcomes may be worse than they would have been in the base game. We give tight bounds on this phenomenon in a simple class of loadbalancing games, over arbitrary social networks, and present some extensions.
Word of Mouth Propagation in Online Social Networks
 Journal of Networks
, 2012
"... Abstract—Online social networks (OSNs) are becoming an important propagation platform for Word of mouth (WOM). Therefore, it is of great significance to study the propagation of WOM in OSNs. A WOM propagation model named NPN is proposed in this paper, and some simulation experiments are carried ou ..."
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Abstract—Online social networks (OSNs) are becoming an important propagation platform for Word of mouth (WOM). Therefore, it is of great significance to study the propagation of WOM in OSNs. A WOM propagation model named NPN is proposed in this paper, and some simulation experiments are carried out to investigate the mechanism of WOM propagation. From the sensitivity analysis of degree of initial information source node, it can be seen that the degree of initial information source node determines the scope and speed of the propagation of WOM in OSNs in some extent. Then the sensitivity analysis of number of initial information source nodes shows that the initial source nodes are crucial for controlling the propagation of negative information in OSNs. Moreover, from the user behavior respect, it is found that different user behavior in OSNs causes different propagation results, the more users who are willing to diffuse WOM, the more scope WOM can propagate and the faster the information diffuses. Findings in this paper are helpful for enterprises to form an effective WOM. Index Terms—word of mouth, online social networks, information propagation/diffusion I.
Social Context in Potential Games
"... Abstract. A prevalent assumption in game theory is that all players act in a purely selfish manner, but this assumption has been repeatedly questioned by economists and social scientists. In this paper, we study a model that allows to incorporate the social context of players into their decision mak ..."
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Abstract. A prevalent assumption in game theory is that all players act in a purely selfish manner, but this assumption has been repeatedly questioned by economists and social scientists. In this paper, we study a model that allows to incorporate the social context of players into their decision making. We consider the impact of otherregarding preferences in potential games, one of the most popular and central classes of games in algorithmic game theory. Our results concern the existence of pure Nash equilibria and potential functions in games with social context. The main finding is a tight characterization of the class of potential games that admit exact potential functions for any social context. In addition, we prove complexity results on deciding existence of pure Nash equilibria in numerous popular classes of potential games, such as different classes of load balancing, congestion, cost and market sharing games. 1
Bayesian Auctions with Friends and Foes
"... Abstract. We study auctions whose bidders are embedded in a social or economic network. As a result, even bidders who do not win the auction themselves might derive utility from the auction, namely, when a friend wins. On the other hand, when an enemy or competitor wins, a bidder might derive negati ..."
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Abstract. We study auctions whose bidders are embedded in a social or economic network. As a result, even bidders who do not win the auction themselves might derive utility from the auction, namely, when a friend wins. On the other hand, when an enemy or competitor wins, a bidder might derive negative utility. Such spite and altruism will alter the bidding strategies. A simple and natural model for bidders ’ utilities in these settings posits that the utility of a losing bidder i as a result of bidder j winning is a constant (positive or negative) fraction of bidder j’s utility. We study such auctions under a Bayesian model in which all valuations are distributed independently according to a known distribution, but the actual valuations are private. We describe and analyze Nash Equilibrium bidding strategies in two broad classes: regular friendship networks with arbitrary valuation distributions, and arbitrary friendship networks with identical uniform valuation distributions. 2 1