Interaktivität, Interaktion, Internet

In recent years, numerous suggestions have been made to clarify the concept of interactivity in communication science. Most often, an inclusion strategy is used, in which diverse definitions are summarized into a multi-dimensional notion of interactivity. Aside from this, there is also an exclusion strategy: On the one hand, certain technical media (computer-mediated communication, »interactive television«) or communicative situations (face-to-face communication) are marked as »interactive«. In doing this, no differentiation is made between potential and process, and betwen »interactivity« and »interaction«. On the other hand, the notion of interaction as it is rooted in sociology offers itself for a theoretically grounded definition. Seven ways of using the term in relationsship to the notion of communication can be found. It is suggested to conceptualize interaction as a type of communication in the sense of Rafaeli: Interactive communication is reciprocal and relates to earlier messages. The concept of interactive communication chosen here can be linked with systems theory and the deliberative theory of the public sphere.     

ROBUST BOUNDS FOR FORWARD START OPTIONS

We consider the problem of finding a model‐free upper bound on the price of a forward start straddle with payoff . The bound depends on the prices of vanilla call and put options with maturities T₁ and T₂ , but does not rely on any modeling assumptions concerning the dynamics of the underlying. The bound can be enforced by a super‐replicating strategy involving puts, calls, and a forward transaction. We find an upper bound, and a model which is consistent with T₁ and T₂ vanilla option prices for which the model‐based price of the straddle is equal to the upper bound. This proves that the bound is best possible. For lognormal marginals we show that the upper bound is at most 30% higher than the Black–Scholes price. The problem can be recast as finding the solution to a Skorokhod embedding problem with nontrivial initial law so as to maximize .     

Microenterprises and multiple bank relationships: The case of professionals

The present paper focuses on professionals as a special group of microenterprises. It explains their characteristics and financial relationships, using data from a survey conducted in Germany in 2002. Consistent with the theory of asymmetric information and relationship lending, we find that these firms maintain a small number of bank relationships, which increases in firm size and age. They tend to choose multiple banking relationships to overcome credit rationing and finance larger loans. Credit risk and the structure of the banking market do not seem to matter.     

Industrial Organization of Banking: A Review

Empirical research about structure, conduct and performance in banking markets has developed mostly independently from the microeconomic theory of banking. The present paper reviews the literature by focusing on the links between theoretical and empirical research. It considers basic conditions, variables of market structure, conduct and performance and public policy special to the banking industry. It is shown that the competitive conditions are different in different market segments, and that the trend towards universal banks which are active in different geographic markets gives new challenges to research.