Cotygodniowe seminarium badawcze (brak strony WWW)
2018-10-18, godz. 10:15, 4050
Marcin Dziubiński (Instytut Informatyki, UW)
We propose and study a strategic model of hiding in a network, where the network designer chooses the links and his position in the network facing the seeker who inspects and disrupts the network. We characterize optimal networks for the hider, as well as equilibrium hiding and seeking strategies on...
2018-05-10, godz. 10:15, 4050
Tomasz Wąs (Instytut Informatyki, UW)
Axiomatization of the PageRank centrality
We propose an axiomatization of PageRank. Specifically, we introduce five simple axioms – Foreseeability, Outgoing Homogeneity, Monotonicity, Merging, and Dummy Node – and show that PageRank is the only centrality measure that satisfies all of them. Our axioms give new conceptual and ...
2018-04-12, godz. 10:15, 4050
Piotr Skowron (Instytut Informatyki UW)
Approximating Optimal Social Choice under Metric Preferences
We consider voting under metric preferences: both voters and alternatives are associated with points in a metric space, and each voter prefers alternatives that are closer to her to ones that are further away. In this setting, it is often desirable to select an alternative that minimizes the sum of ...
2018-03-29, godz. 10:15, 4050
Krzysztof Rządca (Instytut Informatyki, UW)
Collective Schedules: Scheduling Meets Computational Social Choice
When scheduling public works or events in a shared facility one needs to accommodate preferences of a population. We formalize this problem by introducing the notion of a collective schedule. We show how to extend fundamental tools from social choice theory---positional scoring rules, the Kemeny ru...
2018-03-15, godz. 10:15, 4790
Jadwiga Sosnowska (Instytut Informatyki UW)
Path Evaluation and Centralities in Weighted Graphs – An Axiomatic Approach
We study the problem of extending the classic centrality measures to weighted graphs. Unfortunately, in the existing extensions, paths in the graph are evaluated solely based on their weights, which is a restrictive and undesirable assumption for a variety of settings. Given this, we define a notion...
2018-01-25, godz. 10:15, 4790
Rahul CS (Instytut Informatyki, UW)
Group Activity Selection parameterized by the Number of Agent Types
We study the parameterized complexity of GASP (Group Activity Selection Problem) and its variant gGASP w.r.t. the number of different agent types as a parameter. We show that GASP can be solved in polynomial time if the number of agent types is a constant and complement this result with a strong par...
2018-01-11, godz. 10:15, 4790
Oskar Skibski (Instytut Informatyki, UW)
A Pseudo-Polynomial Algorithm for Computing Power Indices in Graph-Restricted Weighted Voting Games
Weighted voting games allow for studying the distribution of power between agents in situations of collective decision making. While the conventional version of these games assumes that any agent is always ready to cooperate with all others, recently, more involved models have been proposed, where c...
2017-12-21, godz. 10:15, 4790
Marcin Waniek (Khalifa University of Science and Technology)
Spreading of ideas in a social network is usually modelled in the literature as a stochastic process. However, in many real-life applications the exact course of the diffusion can be guided by a certain individual or authority. Given this background, we analyse a setting in which the process of spre...
2017-12-07, godz. 10:15, 4790
Jan Woźnica (Instytut Informatyki, UW)
Strategic Evasion of Centrality Measures
Among the most fundamental tools for social network analysis are centrality measures, which are designed to rank nodes according to various criteria. Similarly to other tools, they were built around the assumption that individuals in the network do not act strategically to evade analysis. Even the c...
2017-11-30, godz. 10:15, 4790
Marcin Dziubiński (Instytut Informatyki, UW)
Hide and seek game with heterogenous hiding places
We study a conflict with multiple battlefields where two players, the hider and the seeker, choose their respective numbers of hiding places. The hiding places have different values and the score of the hider is the sum of values of the places chosen by him and not chosen by the seeker. The score of...