TY - GEN
AB - We analyze the stability of networks when two intermediaries strategically form costly links to customers. We interpret these links as customer relationships that enable trade to sell a product. Equilibrium prices and equilibrium quantities on the output as well as on the input market are determined endogenously for a given network of customer relationships. We investigate in how far the substitutability of the intermediaries' products and the costs of link formation influence the intermediaries' equilibrium profits and thus have an impact on the incentives to strategically form relationships to customers. For networks with three customers we characterize locally stable networks, in particular existence is guaranteed for any degree of substitutability. Moreover for the special cases of perfect complements, independent products and perfect substitutes, local stability coincides with the stronger concept of Nash stability. Additionally, for networks with n customers we analyze stability regions for selected networks and determine their limits when n goes to infinity. It turns out that the shape of the stability regions for those networks does not significantly change compared to a setting with a small number of customers.
AU - Brangewitz, Sonja
AU - Haake, Claus-Jochen
AU - Möhlmeier, Philipp
ID - 249
TI - Strategic Formation of Customer Relationship Networks
VL - 91
ER -
TY - GEN
AU - Pfannschmidt, Karlson
ID - 251
TI - Solving the aggregated bandits problem
ER -
TY - CONF
AB - We investigate a non-cooperative game-theoretic model for the formation of communication networks by selfish agents. Each agent aims for a central position at minimum cost for creating edges. In particular, the general model (Fabrikant et al., PODC'03) became popular for studying the structure of the Internet or social networks. Despite its significance, locality in this game was first studied only recently (Bilò et al., SPAA'14), where a worst case locality model was presented, which came with a high efficiency loss in terms of quality of equilibria. Our main contribution is a new and more optimistic view on locality: agents are limited in their knowledge and actions to their local view ranges, but can probe different strategies and finally choose the best. We study the influence of our locality notion on the hardness of computing best responses, convergence to equilibria, and quality of equilibria. Moreover, we compare the strength of local versus non-local strategy changes. Our results address the gap between the original model and the worst case locality variant. On the bright side, our efficiency results are in line with observations from the original model, yet we have a non-constant lower bound on the Price of Anarchy.
AU - Cord-Landwehr, Andreas
AU - Lenzner, Pascal
ID - 275
T2 - Proceedings of the 40th Conference on Mathematical Foundations of Computer Science (MFCS)
TI - Network Creation Games: Think Global - Act Local
ER -
TY - JOUR
AU - Gries, Thomas
AU - Feng, Yuanhua
AU - Guo, Zhichao
ID - 2816
IS - 2
JF - China Agricultural Economic Review
TI - Changes of China’s agri-food exports to Germany caused by its accession to WTO and the 2008 financial crisis
VL - 7
ER -
TY - GEN
AU - Kirsch, Michelle
ID - 282
TI - Koordinierter Patentschutz in einer globalisierten Welt - Effizienz- und Anreizwirkungen auf die Arzneimittelversorgung in Entwicklungsländern
ER -
TY - CONF
AB - The size of modern data centers is constantly increasing. As it is not economic to interconnect all machines in the data center using a full-bisection-bandwidth network, techniques have to be developed to increase the efficiency of data-center networks. The Software-Defined Network paradigm opened the door for centralized traffic engineering (TE) in such environments. Up to now, there were already a number of TE proposals for SDN-controlled data centers that all work very well. However, these techniques either use a high amount of flow table entries or a high flow installation rate that overwhelms available switching hardware, or they require custom or very expensive end-of-line equipment to be usable in practice. We present HybridTE, a TE technique that uses (uncertain) information about large flows. Using this extra information, our technique has very low hardware requirements while maintaining better performance than existing TE techniques. This enables us to build very low-cost, high performance data-center networks.
AU - Wette, Philip
AU - Karl, Holger
ID - 287
T2 - Proceedings of the 4th European Workshop on Software Defined Networks (EWSDN 2015)
TI - HybridTE: Traffic Engineering for Very Low-Cost Software-Defined Data-Center Networks
ER -
TY - GEN
AU - Materna, GinaJoanna
ID - 294
TI - Fair Trade - Eine neue Perspektive in der internationalen Handelspolitik
ER -
TY - GEN
AU - Zindler, Finn
ID - 256
TI - Selektive Vertriebssysteme am Fallbeispiel der Adidas AG - eine wettbewerbspolitische Beurteilung
ER -
TY - JOUR
AB - In the last two decades, water consumption in Germany has been decreasing, which causes the water tanks and pipes in water distribution systems to work inefficiently. This paper proposes a method that supports the planning process for tanks in water distribution systems. The method uses a combination of network reduction, mathematical optimization and hydraulic simulation. The mathematical optimization model is a non-convex Mixed Integer Quadratically Constrained Program (MIQCP) that is solved by a piecewise linearization. As this may lead to many binary variables and therefore high computing times, the size of the water distribution system model is reduced before building the optimization model. After applying several network reduction techniques and using a piecewise approximation of the original model, there may be some hydraulic differences between the original network model and the reduced network model. To make sure that the solution obtained in the optimization process is feasible in the original water distribution system model, the solution is verified by a hydraulic simulation. If the solution is not feasible, the reduced model has to be modified and solved again until the hydraulic simulation verifies a solution as feasible. In this paper, each of these processes is described and the results indicate the usefulness of each of them.
AU - Hallmann, Corinna
AU - Suhl, Leena
ID - 263
JF - OR Spectrum
TI - Optimizing Water Tanks in Water Distribution Systems by combining Network Reduction, Mathematical Optimization and Hydraulic Simulation
ER -
TY - CONF
AU - Bergsma, Florian
AU - Jager, Tibor
AU - Schwenk, Jörg
ID - 3124
T2 - Public-Key Cryptography - PKC 2015 - 18th IACR International Conference on Practice and Theory in Public-Key Cryptography, Gaithersburg, MD, USA, March 30 - April 1, 2015, Proceedings
TI - One-Round Key Exchange with Strong Security: An Efficient and Generic Construction in the Standard Model
ER -
TY - GEN
AB - On an intermediate goods market we allow for vertical and horizontal product differentiation and analyze the influence of simultaneous competition for resources and customers on the market outcome. Asymmetries between intermediaries cannot arise just from distinct product qualities, but also from different production technologies. The intermediaries face either price or quantity competition on the output market and a monopolistic input supplier on the input market. We find that there exist quality and productivity differences such that for quantity competition only one intermediary is willing to procure inputs from the input supplier, while for price competition both intermediaries are willing to purchase inputs. Considering product innovation for symmetric productivities we derive equilibrium conditions on the investment costs and compare price and quantity competition. It turns out that on the one hand there exist product qualities and degrees of horizontal product differentiation for complements such that asymmetric investment equilibria fail to exist. On the other hand we find that there also exist product qualities and degrees of horizontal product differentiation for substitutes such that existence can be guaranteed if the investment costs are chosen accordingly.
AU - Brangewitz, Sonja
AU - Manegold, Jochen
ID - 314
TI - Competition and Product Innovation of Intermediaries in a Differentiated Duopoly
ER -
TY - JOUR
AU - Ziegert, Steffen
AU - Wehrheim, Heike
ID - 3162
IS - 3-4
JF - Computer Science - R & D
TI - Temporal plans for software architecture reconfiguration
ER -
TY - CONF
AB - Services are self-contained and platform independent software components that aim at maximizing software reuse. The automated composition of services to a target software artifact has been tackled with many AI techniques, but existing approaches make unreasonably strong assumptions such as a predefined data flow, are limited to tiny problem sizes, ignore non-functional properties, or assume offline service repositories. This paper presents an algorithm that automatically composes services without making such assumptions. We employ a backward search algorithm that starts from an empty composition and prepends service calls to already discovered candidates until a solution is found. Available services are determined during the search process. We implemented our algorithm, performed an experimental evaluation, and compared it to other approaches.
AU - Mohr, Felix
AU - Jungmann, Alexander
AU - Kleine Büning, Hans
ID - 319
T2 - Proceedings of the 12th IEEE International Conference on Services Computing (SCC)
TI - Automated Online Service Composition
ER -
TY - GEN
AU - Gerken, Britta
ID - 299
TI - Elektromagnetische Seitenkanalangriffe auf paarungsbasierte Kryptographie
ER -
TY - GEN
AU - Stroh, Christian
ID - 302
TI - Efficient Attributes for Pairing-Based Anonymous Credentials
ER -
TY - GEN
AU - Herrmann, Philipp
AU - Kundisch, Dennis
AU - Zimmermann, Steffen
AU - Nault, Barry
ID - 307
T2 - INFORMS Conference on Information Systems and Technology (CIST)
TI - Different Sources of the Variance of Online Consumer Ratings and their Impact on Price and Demand
ER -
TY - CONF
AB - We introduce weighted boolean formula games (WBFG) as a new class of succinct games. Each player has a set of boolean formulas she wants to get satisfied; the formulas involve a ground set of boolean variables each of which is controlled by some player. The payoff of a player is a weighted sum of the values of her formulas. We consider both pure equilibria and their refinement of payoff-dominant equilibria [34], where every player is no worse-off than in any other pure equilibrium. We present both structural and complexity results:We consider mutual weighted boolean formula games (MWBFG), a subclass of WBFG making a natural mutuality assumption on the formulas of players. We present a very simple exact potential for MWBFG. We establish a polynomial monomorphism from certain classes of weighted congestion games to subclasses of WBFG and MWBFG, respectively, indicating their rich structure.We present a collection of complexity results about decision (and search) problems for both pure and payoff-dominant equilibria in WBFG. The precise complexities depend crucially on five parameters: (i) the number of players; (ii) the number of variables per player; (iii) the number of formulas per player; (iv) the weights in the payoff functions (whether identical or not), and (v) the syntax of the formulas. These results imply that, unless the polynomial hierarchy collapses, decision (and search) problems for payoff-dominant equilibria are harde than for pure equilibria.
AU - Monien, Burkhard
AU - Mavronicolas, Marios
AU - Wagner, Klaus
ID - 232
T2 - the ´Festschrift´ Algorithms, Probability, Networks, and Games: Scientific Papers and Essays Dedicated to Paul G. Spirakis on the Occasion of His 60th Birthday
TI - Weighted Boolean Formula Games
ER -
TY - GEN
AU - Ochlast, Kerstin
ID - 237
TI - Trust Me, I am Certified - Wie die Zertifizierung von Produkten und Verkäufern das Vertrauen von Kunden im Onlinehandel beeinflussen
ER -
TY - GEN
AU - Lange, Alexander
ID - 268
TI - Online Bewertungssysteme – Ein systematischer Überblick
ER -
TY - THES
AU - Abshoff, Sebastian
ID - 270
TI - On the Complexity of Fundamental Problems in Dynamic Ad-hoc Networks
ER -