Contributions in Merlin

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The boards of directors of the largest corporations of a country together with the directors form a dense bipartite network. The board network consists of boards connected through common directors. The director network is obtained taking the directors as nodes, and a membership in the same board as a link. These networks are involved in the decision making processes relevant to the macro-economy of a country. We present an extensive and comparative analysis of the statistical properties of the board network and the director network for the first 1000 US corporations ranked by revenue (“Fortune 1000”) in the year 1999 and for the corporations of the Italian Stock Market. We find several common statistical properties across the data sets, despite the fact that they refer to different years and countries. This suggests an underlying universal formation mechanism which is not captured in a satisfactory way by the existent network models. In particular we find that all the considered networks are Small Worlds, assortative, highly clustered and dominated by a giant component. Several other properties are examined. The presence of a lobby in a board, a feature relevant to decision making dynamics, turns out to be a macroscopic phenomenon in all the data sets.

Strategic decision making, especially in the areas of business intelligence and competitive intelligence, requires the acquisition of decision-relevant information pieces like market trends, fusions and company values. This information is extracted by pre-processing and querying multiple sources, combining and condensing the findings. It is characteristic that the extrac- tion process is resource intensive and has to be performed regularly and quite frequently. In the research project PARMENIDES, we are developing methods that establish ontologies over an application domain, annotate documents with the ontology components and identify the entities in them, so that we can decompose business into conventional queries towards entities and XML-annotated texts.

Kooperative Lehr-/ Lernarrangements kommen der Forderung nach einer modernen kognitivistisch ausgerichteten Ausbildung in besonderer Weise nach. Die mit kooperativem Lernen eng verknüpfte Materialbearbeitung kann durch gezielte Computerunterstützung erheblich vereinfacht, unterstützt und erweitert werden. Annotationssysteme haben sich als wertvolle Ergänzung erwiesen, da sie die bestehende Kluft zwischen Material und Kommunikation sinnvoll überbrücken können. Mit dem Einsatz von mobilen Technologien findet vermehrt spontane und situative Kommunikation statt, wodurch die Kooperationsintensität erhöht wird. Darüber hinaus verbessert sich die in kooperativen Lehr-/ Lernarrangements meist schwierig zu meisternde, aber doch notwendige spontane Koordination. Die präsentierten Ergebnisse wurden im Rahmen des EU-Projektes MOBIlearn (www.mobilearn.org) erarbeitet und finanziell durch das Schweizer Bundesamt für Bildung und Wissenschaft gefördert.

We present a geometric approach to discrete time multiperiod mean variance portfolio optimization that largely simplifies the mathematical analysis and the economic interpretation of such model settings. We show that multiperiod mean variance optimal policies can be decomposed in an orthogonal set of basis strategies, each having a clear economic interpretation. This implies that the corresponding multiperiod mean variance frontiers are spanned by an orthogonal basis of dynamic returns. Specifically, in a k-period model the optimal strategy is a linear combination of a single k-period global minimum second moment strategy and a sequence of k local excess return strategies which expose the dynamic portfolio optimally to each single-period asset excess return. This decomposition is a multi period version of Hansen and Richard (Econometrica (1987)) orthogonal representation of single-period mean variance frontiers and naturally extends the basic economic intuition of the static Markowitz model to the multiperiod context. Using the geometric approach to dynamic mean variance optimization we obtain closed form solutions in the i.i.d. setting for portfolios consisting of both assets and liabilities (AL), each modelled by a distinct state variable. As a special case, the solution of the mean variance problem for the asset only case in Li and Ng (Mathematical Finance 10 (2000)) follows directly and can be represented in terms of simple products of some single period orthogonal returns. We illustrate the usefulness of our geometric representation of multiperiods optimal policies and mean variance frontiers by discussing specific issues related to AL portfolios: The impact of taking liabilities into account on the implied mean variance frontiers, the quantification of the impact of the rebalancing frequency and the determination of the optimal initial funding ratio.

We examine the characteristics and relative strength of third-party sanctions in a series of experiments. We hypothesize that egalitarian distribution norms and cooperation norms apply in our experiments, and that third parties, whose economic payoff is unaffected by the norm violation, may be willing to enforce these norms although the enforcement is costly for them. Almost two-thirds of the third parties indeed punished the violation of the distribution norm and their punishment increased the more the norm was violated. Likewise, up to roughly 60% of the third parties punished violations of the cooperation norm. Thus, our results show that the notion of strong reciprocity extends to the sanctioning behavior of “unaffected” third parties. In addition, these experiments suggest that third-party punishment games are powerful tools for studying the characteristics and the content of social norms. Further experiments indicate that second parties, whose economic payoff is reduced by the norm violation, punish the violation much more strongly than do third parties.

Previous studies have suggested that people holding protected values (PVs) show a bias against harmful acts, as opposed to harmful omissions (omission bias). In the present study, we (1) investigated the relationship between PVs and acts versus omissions in risky choices, using a paradigm in which act and omission biases were presented in a symmetrical manner, and (2) examined whether people holding PVs respond differently to framing manipulations. Participants were given environmental scenarios and were asked to make choices between actions and omissions. Both the framing of the outcomes (positive vs. negative) and the outcome certainty (risky vs. certain) were manipulated. In contrast to previous studies, PVs were linked to preferences for acts, rather than for omissions. PVs were more likely to be associated with moral obligations to act than with moral prohibitions against action. Strikingly, people with strong PVs were immune to framing; participants with few PVs showed robust framing effects.