Thorsten Hens, Klaus Reiner Schenk-Hoppé, Evolutionary finance: introduction to the special issue, Journal of Mathematical Economics, Vol. 41 (1-2), 2005. (Journal Article)
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Thorsten Hens, Klaus Reiner Schenk-Hoppé, Evolutionary stability of portfolio rules in incomplete markets, Journal of Mathematical Economics, Vol. 41 (1-2), 2005. (Journal Article)
This paper studies the evolution of wealth shares of portfolio rules in incomplete markets with short-lived assets. Prices are determined endogenously. The performance of a portfolio rule in the process of repeated reinvestment of wealth is determined by the wealth share eventually conquered in competition with other portfolio rules. Using random dynamical systems theory, we derive necessary and sufficient conditions for the evolutionary stability of portfolio rules. In the case of Markov (in particular i.i.d.) payoffs these local stability conditions lead to a simple portfolio rule that is the unique evolutionary stable strategy. This rule possesses an explicit representation. Moreover, it is demonstrated that mean–variance optimization is not evolutionary stable while the CAPM-rule always imitates the best portfolio rule and survives. |
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Rabah Amir, Igor V Evstigneev, Thorsten Hens, Klaus Reiner Schenk–Hoppé, Market selection and survival of investment strategies, Journal of Mathematical Economics, Vol. 41 (1-2), 2005. (Journal Article)
The paper analyzes the process of market selection of investment strategies in an incomplete market of short-lived assets. In the model under study, asset payoffs depend on exogenous random factors. Market participants use dynamic investment strategies taking account of the available information about current and previous events. It is shown that an investor allocating wealth across the assets according to their conditional expected payoffs eventually accumulates total market wealth, provided the investor’s strategy is asymptotically distinct from the portfolio rule suggested by the Capital Asset Pricing Model (CAPM). This assumption turns out to be essentially necessary for the result. |
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Hans Degryse, Steven Ongena, Distance, Lending Relationships, and Competition, Journal of Finance, Vol. 60 (1), 2005. (Journal Article)
We study the effect on loan conditions of geographical distance between firms, the lending bank, and all other banks in the vicinity. For our study, we employ detailed contract information from more than 15,000 bank loans to small firms comprising the entire loan portfolio of a large Belgian bank. We report the first comprehensive evidence on the occurrence of spatial price discrimination in bank lending. Loan rates decrease with the distance between the firm and the lending bank and increase with the distance between the firm and competing banks. Transportation costs cause the spatial price discrimination we observe. |
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Abraham Bernstein, Esther Kaufmann, Christoph Bürki, Mark Klein, How Similar Is It? Towards Personalized Similarity Measures in Ontologies, In: 7. Internationale Tagung Wirtschaftsinformatik, February 2005. (Conference or Workshop Paper)
Finding a good similarity assessment algorithm for the use in ontologies is central to the functioning of techniques such as retrieval, matchmaking, clustering, data-mining, ontology translations, automatic database schema matching, and simple object comparisons. This paper assembles a catalogue of ontology based similarity measures, which are experimentally compared with a �similarity gold standard� obtained by surveying 50 human subjects. Results show that human and algorithmic similarity predications varied substantially, but could be grouped into cohesive clusters. Addressing this variance we present a personalized similarity assessment procedure, which uses a machine learning component to predict a subject�s cluster membership, providing an excellent prediction of the gold standard. We conclude by hypothesizing ontology dependent similarity measures. |
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Abraham Bernstein, Peter Vorburger, Patrice Egger, Direct Interruptablity Prediction and Scenario-based Evaluation of Wearable Devices: Towards Reliable Interruptability Predictions, In: First International Workshop on Managing Context Information in Mobile and Pervasive Environments MCMP-05, February 2005. (Conference or Workshop Paper)
In this paper we introduce the approach of direct interruptability inference from accelerometer and audio data and show that it provides highly accurate and robust predictions. Furthermore, we argue that scenarios are central for evaluating the performance of interruptability predicting devices and prove it on our setup. We also demonstrate that scenarios provide the foundation for avoiding misleading results, assessing the results’ generalizability, and provide the basis for a stratified scenario-based learning model, which greatly speeds-up the training of such devices.
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Abraham Bernstein, Esther Kaufmann, Norbert E. Fuchs, Talking to the Semantic Web - A Controlled English Query Interface for Ontologies, AIS SIGSEMIS Bulletin, Vol. 2 (1), 2005. (Journal Article)
The semantic web presents the vision of a distributed, dynamically growing knowledge base founded on formal logic. Common users, however, seem to have problems even with the simplest Boolean expression. As queries from web search engines show, the great majority of users simply do not use Boolean expressions. So how can we help users to query a web of logic that they do not seem to understand?
We address this problem by presenting a natural language front-end to semantic web querying. The front-end allows formulating queries in Attempto Controlled English (ACE), a subset of natural English. Each ACE query is translated into a discourse representation structure – a variant of the language of first-order logic – that is then translated into the semantic web querying language PQL. As examples show, our approach offers great potential for bridging the gap between the semantic web and its real-world users, since it allows users to query the semantic web without having to learn an unfamiliar formal language. |
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R Lario, Renato Pajarola, F Tirado, Cached Geometry Manager for View-dependent LOD Rendering, In: International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision, 2005-01-31. (Conference or Workshop Paper published in Proceedings)
The new generation of commodity graphics cards with significant on-board video memory has become widely
popular and provides high-performance rendering and flexibility. One of the features to be exploited with this
hardware is the use of the on-board video memory to store geometry information. This strategy significantly
reduces the data transfer overhead from sending geometry data over the (AGP) bus interface from main memory
to the graphics card. However, taking advantage of cached geometry is not a trivial task because the data models
often exceed the memory size of the graphics card. In this paper we present a dynamic Cached Geometry
Manager (CGM) to address this issue. We show how this technique improves the performance of real-time
view-dependent level-of-detail (LOD) selection and rendering algorithms of large data sets. Alternative caching
approaches have been analyzed over two different view-dependent progressive mesh (VDPM) frameworks: one
for rendering of arbitrary manifold 3D meshes, and one for terrain visualization. |
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Helmut Max Dietl, Egon Franck, Stars sollen sie sein, In: Der Tagesspiegel, p. 21, 31 January 2005. (Newspaper Article)
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Helmut Max Dietl, Das System ist krank. Sport könnte auch rentabel sein - nordamerikanische Ligen machen es vor, In: St. Galler Tagblatt, p. 3, 17 January 2005. (Newspaper Article)
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Andrea Schenker-Wicki, Finanziell überforderte Hochschulträger vor höheren Studiengebühren, In: Moderation Schweizerischer Studentenverein. 2005. (Conference Presentation)
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Daniel Fasnacht, Kunden wollen nicht nur Produkte, sondern auch Lösungen, IO new Management : Zeitschrift für Unternehmenswissenschaften und Führungspraxis, Vol. 74 (10), 2005. (Journal Article)
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Daniel Fasnacht, Netzwerkmodell zur Simulation von kritischen Erfolgsfaktoren oder wie komplexe IT-Projekte ganzheitlich geführt werden, In: Business Engineering in der Praxis, Springer Berlin Heidelberg, Berlin, Heidelberg, p. 455 - 478, 2005. (Book Chapter)
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Thorsten Hens, János Mayer, Beate Pilgrim, Existence of Sunspot Equilibria and Uniqueness of Spot Market Equilibria: The Case of Intrinsically Complete Markets, In: Essays in Dynamic General Equilibrium Theory : Festschrift for David Cass, Springer (Bücher), Berlin, p. 75 - 106, 2005. (Book Chapter)
We consider economies with additively separable utility functions and give conditions for the two-agents case under which the existence of sunspot equilibria is equivalent to the occurrence of the transfer paradox. This equivalence enables us to show that sunspots cannot matter if the initial economy has a unique spot market equilibrium and there are only two commodities or if the economy has a unique equilibrium for all distributions of endowments induced by asset trade. For more than two agents the equivalence breaks and we give an example for sunspot equilibria even though the economy has a unique equilibrium for all distributions of endowments induced by asset trade. |
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Ashkan Nikeghbali, Marc Yor, A definition and some characteristic properties of pseudo-stopping times, Annals of Probability, Vol. 33 (5), 2005. (Journal Article)
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Klaus Fiedler, Wolfram Schenck, Marlin Watling, Jochen Menges, Priming trait inferences through pictures and moving pictures: the impact of open and closed mindsets, Journal of Personality and Social Psychology, Vol. 88 (2), 2005. (Journal Article)
A newly developed paradigm for studying spontaneous trait inferences (STI) was applied in 3 experiments. The authors primed dyadic stimulus behaviors involving a subject (S) and an object (O) person through degraded pictures or movies. An encoding task called for the verification of either a graphical feature or a semantic interpretation, which either fit or did not fit the primed behavior. Next, participants had to identify a trait word that appeared gradually behind a mask and that either matched or did not match the primed behavior. STI effects, defined as shorter identification latencies for matching than nonmatching traits, were stronger for S than for O traits, after graphical rather than semantic encoding decisions and after encoding failures. These findings can be explained by assuming that trait inferences are facilitated by open versus closed mindsets supposed to result from distracting (graphical) encoding tasks or encoding failures (involving nonfitting interpretations). |
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Rina Rosenblatt-Wisch, Optimal Growth under Loss Aversion, University of Zurich, Faculty of Economics, Business Administration and Information Technology, 2005. (Dissertation)
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Marc Schindler, Rumors in Financial Markets - Insights into a perceived mystery, University of Zurich, Faculty of Economics, Business Administration and Information Technology, 2005. (Dissertation)
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Andreas Blöchlinger, Econometric advancements in market and credit risk modeling, University of Zurich, Faculty of Economics, Business Administration and Information Technology, 2005. (Dissertation)
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Stefano Battiston, Diego Garlaschelli, Maurizio Castri, Vito D P Servedio, Guido Caldarelli, The scale-free topology of market investments, Physica A: Statistical Mechanics and its Applications, Vol. 350 (2), 2005. (Journal Article)
We propose a network description of large market investments, where both stocks and shareholders are represented as vertices connected by weighted links corresponding to shareholdings. In this framework, the in-degree ($k_{in}$) and the sum of incoming link weights (v) of an investor correspond to the number of assets held (portfolio diversification) and to the invested wealth (portfolio volume), respectively. An empirical analysis of three different real markets reveals that the distributions of both $k_{in}$ and v display power-law tails with exponents y and a. Moreover, we find that $k_{in}$ scales as a power-law function of v with an exponent b. Remarkably, despite the values of a, b and y differ across the three markets, they are always governed by the scaling relation b = (1-a)/(1-y). We show that these empirical findings can be reproduced by a recent model relating the emergence of scale-free networks to an underlying Paretian distribution of ‘hidden’ vertex properties. |
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