TY - CONF
AU - Müller, Michelle
AU - Gutt, Dominik
ID - 6856
T2 - Wirtschaftsinformatik Proceedings 2019
TI - Heart over Heels? An Empirical Analysis of the Relationship between Emotions and Review Helpfulness for Experience and Credence Goods
ER -
TY - CONF
AB - We investigate the maintenance of overlay networks under massive churn, i.e.
nodes joining and leaving the network. We assume an adversary that may churn a
constant fraction $\alpha n$ of nodes over the course of $\mathcal{O}(\log n)$
rounds. In particular, the adversary has an almost up-to-date information of
the network topology as it can observe an only slightly outdated topology that
is at least $2$ rounds old. Other than that, we only have the provably minimal
restriction that new nodes can only join the network via nodes that have taken
part in the network for at least one round.
Our contributions are as follows: First, we show that it is impossible to
maintain a connected topology if adversary has up-to-date information about the
nodes' connections. Further, we show that our restriction concerning the join
is also necessary. As our main result present an algorithm that constructs a
new overlay- completely independent of all previous overlays - every $2$
rounds. Furthermore, each node sends and receives only $\mathcal{O}(\log^3 n)$
messages each round. As part of our solution we propose the Linearized DeBruijn
Swarm (LDS), a highly churn resistant overlay, which will be maintained by the
algorithm. However, our approaches can be transferred to a variety of classical
P2P Topologies where nodes are mapped into the $[0,1)$-interval.
AU - Götte, Thorsten
AU - Vijayalakshmi, Vipin Ravindran
AU - Scheideler, Christian
ID - 6976
T2 - Proceedings of the 2019 IEEE 33rd International Parallel and Distributed Processing Symposium (IPDPS '19)
TI - Always be Two Steps Ahead of Your Enemy - Maintaining a Routable Overlay under Massive Churn with an Almost Up-to-date Adversary
ER -
TY - THES
AB - This thesis investigates approximate pure Nash equilibria in different game-theoretic models. In such an outcome, no player can improve her objective by more than a given factor through a deviation to another strategy. In the first part, we investigate two variants of Congestion Games in which the existence of pure Nash equilibria is guaranteed through a potential function argument. However, the computation of such equilibria might be hard. We construct and analyze approximation algorithms that enable the computation of states with low approximation factors in polynomial time. To show their guarantees we use sub games among players, bound the potential function values of arbitrary states and exploit a connection between Shapley and proportional cost shares. Furthermore, we apply and analyze sampling techniques for the computation of approximate Shapley values in different settings. In the second part, we concentrate on the existence of approximate pure Nash equilibria in games in which no pure Nash equilibria exist in general. In the model of Coevolving Opinion Formation Games, we bound the approximation guarantees for natural states nearly independent of the specific definition of the players' neighborhoods by applying a concept of virtual costs. For the special case of only one influential neighbor, we even show lower approximation factors for a natural strategy. Then, we investigate a two-sided Facility Location Game among facilities and clients on a line with an objective function consisting of distance and load. We show tight bounds on the approximation factor for settings with three facilities and infinitely many clients. For the general scenario with an arbitrary number of facilities, we bound the approximation factor for two promising candidates, namely facilities that are uniformly distributed and which are paired.
AU - Feldotto, Matthias
ID - 8080
TI - Approximate Pure Nash Equilibria in Congestion, Opinion Formation and Facility Location Games
ER -
TY - CHAP
AU - Laubenstein, Désirée
AU - Guthöhrlein, Kirsten
AU - Lindmeier, Christian
AU - Scheer, David
AU - Sponholz, Dirk
ID - 8749
SN - 9783030115173
T2 - Inclusive Mathematics Education
TI - The ‘Learning Office’ as an Approach for Inclusive Education in Mathematics: Opportunities and Challenges
ER -
TY - JOUR
AB - Models on network formation have often been extended to include the potential of network disruption in recent years. Whereas the theoretical research on network formation under the threat of disruption has thus gained prominence, hardly any experimental research exists so far. In this paper, we therefore experimentally study the emergence of networks including the aspect of a known external threat by relating theoretical predictions by Dzuibiński and Goyal (2013) to actual observed behaviour. We deal with the question if subjects in the role of a strategic Designer are able to form safe networks for least costs while facing a strategic Adversary who is going to attack their networks. Varying the costs for protecting nodes, we designed and tested two treatments with different predictions for the equilibrium network and investigated whether one of the least cost equilibrium networks was more likely to be reached. Furthermore, the influence of the subjects’ farsightedness on their decision-making process was elicited and analysed.
We find that while subjects are able to build safe networks in both treatments, equilibrium networks are only built in one of the two treatments. In the other treatment, predominantly safe networks are built but they are not for least costs. Additionally, we find that farsightedness –as measured in our experiment– has no influence on whether subjects are able to build safe or least cost equilibrium networks. Two robustness settings with a reduced external threat or more liberties to modify the initial networks qualitatively confirm our results. Overall, in this experiment observed behaviour is only partially in line with the theoretical predictions by Dzuibiński and Goyal (2013).
AU - Endres, Angelika Elfriede
AU - Recker, Sonja
AU - Mir Djawadi, Behnud
AU - Hoyer, Britta
ID - 80
JF - Journal of Economic Behavior and Organization
TI - Network Formation and Disruption - An Experiment: Are equilibrium networks too complex?
VL - 157
ER -
TY - GEN
AU - Beckhoff, Yvonne Maria
ID - 8530
TI - There's an App for that - Ein Literaturüberblick über Erfolgsfaktoren für App-Downloads
ER -
TY - GEN
AU - Fath, Jerome Louis
ID - 8840
TI - # Fail - Ein Literaturüberblick über Online-Bewertungen zu Produkt- und Dienstleistungsfehlern
ER -
TY - GEN
AU - Seutter, Janina
ID - 6628
TI - Bewertung von Maschinen-generierten Geschäftsmodell-Ideen: Eine experimentelle Untersuchung
ER -
TY - GEN
AU - Groh, Andreas
ID - 8799
TI - Ideenbewertung durch die Crowd - Ein klassifizierender Literaturüberblick
ER -
TY - JOUR
AU - Goller, Michael
AU - Steffen, Bianca
AU - Harteis, Christian
ID - 8958
IS - 1
JF - Vocations and Learning
SN - 1874-785X
TI - Becoming a Nurse Aide: An Investigation of an Existing Workplace Curriculum in a Nursing Home
VL - 12
ER -