436 research outputs found
Household Portfolios in Germany
No full textThis paper describes portfolio choices of German households in the 1980's and 1990's. We present stylized facts and analyze recent trends of asset ownership rates and asset shares on the basis of national accounts and survey data. We correlate socio-demographic household characteristics with asset shares and ownership, and analyze how German households have adjusted their asset portfolios in response to the policy changes during this time. A particular focus is on the effects of German reunification and the portfolio adjustments of East German households during the transition process.
A Note on the Equivalence of Rationalizability Concepts in Generalized Nice Games
No full textMoulin (1984) describes the class of nice games for which the solution concept of point-rationalizability coincides with iterated elimination of strongly dominated strategies. As a consequence nice games have the desirable property that all rationalizability concepts determine the same strategic solution. However, nice games are characterized by rather strong assumptions. For example, only single-valued best responses are admitted and the individual strategy sets have to be convex and compact subsets of the real line R1. This note shows that equivalence of all rationalizability concepts can be extended to multi-valued best response correspondences. The surprising finding is that equivalence does not hold for individual strategy sets that are compact and convex subsets of Rn with n>1.
Uniqueness Conditions for Point-Rationalizable
No full textThe unique point-rationalizable solution of a game is the unique Nash equilibrium. However, this solution has the additional advantage that it can be justified by the epistemic assumption that it is Common Knowledge of the players that only best responses are chosen. Thus, games with a unique point-rationalizable solution allow for a plausible explanation of equilibrium play in one-shot strategic situations, and it is therefore desireable to identify such games. In order to derive sufficient and necessary conditions for unique point-rationalizable solutions this paper adopts and generalizes the contraction-property approach of Moulin (1984) and of Bernheim (1984). Uniqueness results obtained in this paper are derived under fairly general assumptions such as games with arbitrary metrizable strategy sets and are especially useful for complete and bounded, for compact, as well as for finite strategy sets. As a mathematical side result existence of a unique fixed point is proved under conditions that generalize a fixed point theorem due to Edelstein (1962).
Modeling the Use of Nonrenewable Resources Using a Genetic Algorithm
No full textThis paper shows, how a genetic algorithm (GA) can be used to model an economic process: the interaction of profit-maximizing oil-exploration firms that compete with each other for a limited amount of oil. After a brief introduction to the concept of multi-agent-modeling in economics, a GA-based resource-economic model is developed. Several model runs based on different economic policy assumptions are presented and discussed in order to show how the GA-model can be used to gain insight into the dynamic properties of economic systems. The remainder outlines deficiencies of GA-based multi-agent approaches and sketches how the present model can be improved.
Security And Potential Level Preferences With
No full textThe security level models of Gilboa (1988) and of Jaffray (1988) as well as the security and potential level model of Cohen (1992) accomodate succesfully classical Allais paradoxa while they offer an interesting explanation for their occurrence. However, experimental data suggest a systematic violation of these models when lotteries with low probabilities of bad or good outcomes are involved. The present paper develops an axiomatic model that allows for thresholds in the perception of security and potential levels. The derived representation of preferences accommodates the observed violations of the original security and potential level models and provides a natural explanation for their occurence. Additionally, a more fundamental problem of the original models is resolved.
The Pennsylvania Reemployment Bonus Experiments: How a survival model helps in the analysis of the data
No full textSurvival models for life-time data and other time-to-event data are widely used in many fields, including medicine, the environmental sciences, engineering etc. They have also found recognition in the analysis of economic duration data. This paper provides a reanalysis of the Pennsylvania Reemployment Bonus Experiments, which were conducted in 1988-89 to examine the effect of different types of reemployment bonus offers on the unemployment spell. A Cox-proportional-hazards survival-model is fitted to the data and the results are compared to the results of a linear regression approach and to the results of a quantile regression approach. The Cox-proportional-hazards model provides for a remarkable goodness of fit and yields less effective treatment responses, therefore lower expectations concerning the overall implications of the Pennsylvania experiment. An influence analysis is proposed for obtaining qualitative information on the influence of the covariates at different quantiles. The results of the quantile regression and of the influence analysis show that both the linear regression and the Cox-model still impose stringent restrictions on the way covariates influence the duration distribution, however, due to its flexibility, the Cox-proportional hazards model is more appropriate for analysing the data.
Musikstädte as real and imaginary soundscapes: urban musical images as literary motifs in twentieth-century German modernism
No full textPhDThis study examines German literary images of musical life as part of the wider sound identity of the modern German city at the turn of the twentieth century. Focussing on a forty-year period from 1890 to 1930, synonymous with the emergence of the modern German metropolis as an aesthetic object, the project assesses, compares and contrasts how musical life in the Musikstädte was perceived and portrayed by writers in an increasingly noisy urban environment. How does urban musical life influence and condition city writings? What are the differences and similarities between the writings on various musical cities? Can an urban textual sound identity be derived from these differences and similarities? The approach employed to answer these questions is a new, cross-disciplinary one to urban sound in literature, moving beyond reading the key sounds of the urban soundscape using urban musicology, sensorial anthropology and cultural poetics towards a literary contextualisation of the urban aural experience.
The literary motifs of the symphony, the gramophone and urban noise are put under the spotlight through the analysis of a wide range of modernist works by authors who have a special relationship with music. At the centre of this analysis are the Kaffeehausliteratur authors Hermann Bahr, Alfred Polgar and Peter Altenberg, the then Munich-based author Thomas Mann and the lesser known René Schickele. The analysis of these particular works is framed in the music-geographical context of the Musikstadt and literary underpinnings of this topos, ranging from Ingeborg Bachmann to Hans Mayer and, once again, Thomas Mann. In analysing these texts, the methodological approach devised by Strohm, who identifies the blending of a range of urban sounds as a definition of urban space and identity, is applied. His ideas combine historical literary
analysis, musical history and urban sociology. They are rarely used in the analysis of the auditory environment.Arts and Humanities Research Council
Westfield TrustWestfield Trust Studentship
Arts and Humanities Reseach Council (AHRC
Overconfident but yet well-calibrated and underconfident: A research note on judgmental miscalibration and flawed self-assessment*
No full textThe present paper addresses the question whether overconfidence is an individually stable phenomenon. A within-subjects design was used to investigate whether judgmental miscalibration also reflects tendency to make flawed self-assessments. While the former notion refers to the tendency of individuals to put unrealistic beliefs in their judgments, the latter concerns the tendency of individuals to make inaccurate evaluations of their abilities and performance. On the whole, the paper finds little support that those two tendencies should be related. Depending on the employed measurement, the participants were found to be simultaneously overconfident, well-calibrated, and underconfident.
Ambiguity and Social Interaction
No full textWe examine the impact of ambiguity on economic behaviour. We present a relatively non-technical account of ambiguity and show how it may be applied in economics. Optimistic and pessimistic responses to ambiguity are formally modelled. We show that pessimism has the effect of increasing (decreasing) equilibrium prices under Cournot (Bertrand) competition. We also examine the effects of ambiguity on peace processes. It is shown that ambiguity can act to select equilibria in coordination games with multiple equilibria. Some comparative statics results are derived for the impact of ambiguity in games with strategic complements.
DevID: Blockchain-based Portfolios for Software Developers
No full textDecentralized applications, also known as dApps, are the new paradigm for writing business-critical software. Recruiting developers with appropriate qualifications and skills for this activity is key, yet challenging. The main problem is that the portfolio of developers is usually scattered across centralized platforms like GitHub and LinkedIn, and vendor locked. This can result in an incomplete impression of their capabilities.We address this problem and introduce DevID, a blockchain-based portfolio for developers. Over time, this portfolio enables developers to build up a trustworthy collection of records that showcase their capabilities and expertise. They can import data assets from third parties into a unified DevID portfolio, add projects and skills, and receive endorsements. All portfolio records are stored on a scalable distributed ledger and owned by developers themselves. The essential idea is to exploit the tamper-proof property of the blockchain while providing durable storage.To demonstrate the practical value of DevID, we build the competition-based platform, dAppCoder, for the development of decentralized applications. On dAppCoder clients are able to submit their ideas and developers can find work. dAppCoder utilizes DevID portfolios to match these clients and developers. We fully implement our ideas and conduct a deployment trial. Our trial demonstrates that DevID is efficient at storing portfolio records.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Data-Intensive SystemsSoftware Engineerin
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