Regulierungsmöglichkeiten auf dem Markt für Online-Auktionen

Der deutsche Online-Auktionsanbieter eBay hat seit seiner Gründung seine Gebühren um ein Vielfaches erh?ht. Ist dies mit Kostensteigerungen zu begründen? Verh?lt sich eBay wie ein typischer natürlicher Monopolist auf einem schwer bestreitbaren Markt? Wie kann einer Marktkonzentration entgegengetreten werden? Wie k?nnte eine Regulierung des Marktes aussehen? Korbinian von Blanckenburg, 28, Dipl.-Volkswirt, ist wissenschaftlicher Mitarbeiter am Institut für Finanzwissenschaft der Westf?lischen Wilhelms-Universit?t Münster; Michael Michaelis, 31, ist Dipl.-Jurist.     

Zeit und Produktion

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EU agriculture: Reduced protection from exchange rate instability

In the past, the protection of agriculture in the EU from exchange rate instability was accomplished at the cost of confusing regulations, welfare losses and the discrimination of other sectors. Will the 1993 reform of the Agri-Monetary System, combined with wide 15% European Monetary System margins and the recent GATT agreement, lead to more efficiency in European agriculture?     

Destructive behavior in a Fragile Public Good game

Socially destructive behavior in a public good environment–like damaging public goods–is an underexposed phenomenon in economics. In an experiment we investigate whether such behavior can be influenced by the very nature of an environment. To that purpose we use a Fragile Public Good (FPG) game which puts the opportunity for destructive behavior (taking) on a level playing field with constructive behavior (contributing). We find substantial evidence of destructive decisions, sometimes leading to sour relationships characterized by persistent hurtful behavior. While positive framing induces fewer destructive decisions, shifting the selfish Nash towards minimal taking doubles its share to more than 20%.     

Inferior factor in Cournot oligopoly revisited

We reconsider the recent work by Okuguchi (J Econ 101:125–131, 2010) on (possibly asymmetric) Cournotian firms with two production factors, one being inferior for each firm. It is shown there that an increase in the price of the inferior factor does raise the equilibrium industry output. In addition of providing a simpler and more rigorous proof of that result, we generalize it to the case of technologies with $s\ge 2$ factors and also allow some firms not to use the inferior one.     

The Impact of Upfront Payments on Assortment Decisions in Retailing

There is a contentious debate about the exclusionary effects of upfront payments to be made by manufacturers to place their products on retailers’ shelves. Analyzing a two-stage bargaining process with one downstream retailer and a pool of upstream manufacturers, we find that upfront payments lead to a smaller assortment if the retailer’s bargaining power is high enough and the suppliers’ products are close substitutes.     

Verification of Web Service Compositions: An Operationalization of Correctness and a Requirements Framework for Service-oriented Modeling Techniques

Web service compositions coordinate Web services of different enterprises. They are expected to constitute the foundation of service-oriented architectures, to improve business processes as well as to foster intra- and inter-organizational integration. Especially in inter-organizational contexts, quality of service referring to non-functional requirements and conformance to functional requirements are becoming vital properties. With Web service compositions being asynchronous and distributed systems, the latter property – which is also called correctness – can be shown best by verification. This paper examines from a system-theoretic perspective how correctness can be operationalized for Web service compositions. It also proposes a requirements framework for service-oriented modeling techniques so that correctness can be shown by verification and Web service compositions can be modeled intuitively. In order to show the framework’s principle applicability, an example approach is analyzed with respect to the corresponding requirements.