Co-opetition in Network Tasks Yoram Bachrach, Peter Key, Jeff Rosenschein, Morteza Zadimoghaddam, Ely Porat

Agenda Joint Network TasksAdvertising in NetworksNetwork Security

Negotiation 3

“Collective Buying Power” Quota: 100 Buyers Reward: Discount of $10 (total saving 10*100=$1000) 4 25 Users70 Users50 Users30 Users

Transferable Utility Games

Solution Concepts Cv(C) …

Solution Concepts Cv(C) … Stability Unblocked agreements

Solution Concepts Cv(C) … Fairness (Power) Average contribution across all agent permutations

Solution Concepts Cv(C) … Fairness (Power) Average contribution across all agent coalitions

Solving the Groupon Game Average contribution across all permutations Users %41.67%25% Required: 100 Users 25 Users70 Users50 Users30 Users

Solving the Groupon Game Average contribution across all permutations Users %66.67%16.66% Required: 100 Users 15 Users70 Users50 Users30 Users

Solving the Groupon Game Core: no deviations – Cannot win without the 70 users Users %100%0% Required: 100 Users 15 Users70 Users50 Users30 Users

Display Advertising

Sponsored Search Advertising

Social Network Advertising

Social Advertising In Groupon

Connectivity Games s t

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Richer Model p p p b

Network Reliability p p p b

Network Reliability Models Computer nodes (vertices) connected to each other via network links (edges) – Each link has a certain bandwidth (capacity) Within a time unit, links have a certain probability of failure – Typically networks have some redundancy Classical network reliability works – Each link has a “survival probability”, of remaining in the graph – Compute the probability of obtaining the goal in the surviving graph – Various network goals Source target connectivity (STC-P), full connectivity (FC-P), full connectivity given a backbone infrastructure, connectivity of specific servers, allowing a certain bandwidth between the source and target, … – Complexity Valiant: STC-P is #P-hard Provan and Ball: FC-P is #P hard

Connectivity Games p p p b

Example Network (1)

Example Network (2)

Hotspots and Bargaining

Computational Limitations CG SolutionComputation Power indices Banzhaf, Shapley #P-Complete (even without backbones) Polynomial algorithm for trees General approximations CorePolynomial algorithm Finding veto agents coNP-complete Polynomial algorithm in trees

Network Security Physical networks – Placing checkpoints – Locations for routine checks Computer networks – Protecting servers and links from attacks Various costs for different nodes and links – How easy it is to deploy a check point – Performance degradation for protected servers What agreements would be reached regarding related budgets and rewards?

Security Crowdsourcing Texas Virtual Boarder Watch – Individuals observe US-Mexico border for suspicious behavior

Blocking an adversary s t

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Incorporating costs s t

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Multiple Adversaries s1 t s2 3 2 t

Coalitions in Network Security Agents must for coalitions to successfully block the adversary – How should they split costs and rewards? Security resources are limited – Which node should be allocated these resources first? Similar tools from Game Theory s t

Path Disruption Games Games played on a graph G= (a network) – Simple version (PDGs): coalition wins if it can block the adversary and loses otherwise – Model with costs (PDGCs): a coalition is guaranteed a reward r for blocking the adversary, but incurs the cost of its checkpoints

Computational Limitations PDG SolutionComputation Coalition utility (optimal strategy)NP-Hard for multiple adversaries and costs Polynomial algorithm for other cases Power indices Banzhaf, Shapley #P-Complete even for single adversary and no costs CorePolynomial algorithm Polynomial algorithm for single adversary NP-Complete for multiple adversaries

Related Models Network Flow Games – C’s value: the maximal flow it can send between s and t Collusion in network auctions – Procurer buys a path from s to t in an auction – C’s value: obtained price when rigging the auction

Conclusions p p p b s t