Model-free portfolio theory: A rough path approach

Based on a rough path foundation, we develop a model-free approach to stochastic portfolio theory (SPT). Our approach allows to handle significantly more general portfolios compared to previous model-free approaches based on Föllmer integration. Without the assumption of any underlying probabilistic model, we prove a pathwise formula for the relative wealth process, which reduces in the special case of functionally generated portfolios to a pathwise version of the so-called master formula of classical SPT. We show that the appropriately scaled asymptotic growth rate of a far reaching generalization of Cover's universal portfolio based on controlled paths coincides with that of the best retrospectively chosen portfolio within this class. We provide several novel results concerning rough integration, and highlight the advantages of the rough path approach by showing that (nonfunctionally generated) log-optimal portfolios in an ergodic Itô diffusion setting have the same asymptotic growth rate as Cover's universal portfolio and the best retrospectively chosen one.     

Analysis of the effect of charging infrastructure design on electric taxi driving profiles: A case study approach on the example of Singapore

Replacing conventional vehicle taxis with electric vehicles would be an efficient measure to reduce greenhouse gas emissions. Due to the limited range and long charging times of current battery electric vehicles, it is of utmost importance to provide sufficient charging facilities. This article analyses the impact of the placement and charging power of charging stations on potential mileage and revenue of electric taxis on the example of Singapore. Therefore, we developed an agent-based electric taxi simulation model to investigate electric taxis’ driving profiles with respect to different vehicle types and charging infrastructure designs. This model is also capable of simulating conventional taxi driving profiles. The validation of these simulation results with real taxi data showed that the model is reproducing taxi driving profiles with high accuracy in great detail. We found out that electric taxis could reach the same mileage and revenue as conventional taxis if charging with a power of 160?kW is possible. Furthermore, we discovered that waiting times for available charging stations have a stronger effect on revenue than the length of detours to reach charging stations. Based on these findings, we concluded that it is more important to reduce waiting times by placing sufficient numbers of charging stations at each location before expanding the charging network by installing small numbers of charging stations at many locations.     

Editorial—The Macroeconomics of EMU: Policy Rules and International Implications

Open Economies Review -     

The effect of oil price shocks on asset markets: Evidence from oil inventory news

We quantify the reaction of U.S. equity, bond futures, and exchange rate returns to oil price shocks driven by oil inventory news. Across most sectors, equity prices decrease in response to higher oil prices before the 2007/2008 crisis but increase after it. Positive oil price shocks cause a depreciation of the U.S. dollar against a broad range of currencies but have only a modest effect on bond futures returns. The evidence suggests that changes in risk premia help to explain the time-varying effect of oil price shocks on U.S. equity returns.     

Shall the New EU Members Introduce the Euro? Some Macroeconomic Policy Effects

After the EU enlargement in 2004, there is a clear commitment of the EU and the new member states to aim at an enlargement of the euro zone within the European Economic and Monetary Union (EMU) as well. This might have significant effects on the old EMU, the new members, and even on the global economy. The present paper analyzes some macroeconomic effects and particularly the impact on the effects of stabilization policies when switching to an enlarged euro zone under different assumptions about fiscal and monetary policy regimes in Europe and under alternative types of economic shocks. Also, the implications for the US of different European monetary regimes are evaluated. The results suggest that economic benefits for all countries are rather small. For the Central and Eastern European countries (CEECs), even disadvantages may dominate.     

Ökonomische Bewertung des Repowering von Onshore-Windenergieanlagen in Deutschland

Wind power takes a leading role among the renewable energy sources. Whereas in offshore wind power utilization large technical challenges still need to be tackled for commercial exploitation, the replacement of obsolete plants (repowering) in the onshore sector provides an interesting alternative. This paper first provides an overview of the technical, legal and social development concerning wind power utilization in general, and repowering in particular, in Germany. In a next step, by means of model-based analysis, the technical potential for wind power by means of repowering is determined. The theoretical potential is valuated against social aspects. Due to the large heterogeneity of candidate sites for repowering, general potential studies are not suitable for concrete investment decisions. Instead, a detailed economic feasibility study is required. In our study, we performed scenario analysis, also taking into account the repowering-specific risks. The parameter values varied are those for the quality of the site, the size of the wind park, and the age of the wind turbines to be replaced. Finally, we discuss the results and provide an outlook on the development of repowering in light of the novelized EEG. We find that, until now, the repowering potential could not be fully exploited. An intensified realization of repowering projects in the coming years can be expected, due to the technical potential, simplifications in the commissioning process, rising acceptance on the side of the communities due to changes in the tax legislation and, above all, thanks to the incentives for almost all onshore wind parks.     

Die Kriterien des unteren Wendepunktes im Konjunkturverlauf

Ohne ZusammenfassungVortrag, gehalten vor den Mitgliedern des Großraumausschusses der Südostgemeinschaft der Wiener Hochschulen.     

An empirical investigation of the sustainability of the public deficit in Portugal

In this paper, we investigate Portuguese government expenditures and revenues as an example for a long time series. Our hypothesis states that there may be periods when the deficit is sustainable and those when it is not. Usually, after a period of unsustainable deficits, a new regime takes over. These regime shifts call for an approach that takes into account a non-constant structure of the underlying data generating process. Consequently, we use different tests which we set up in a time-varying framework. We apply and compare the results of the Trace test, Breitung’s non-parametric test and the Bohn test. We identify several break points and find that the Trace test performs worst in this case while Breitung’s test and the Bohn test give similar results. Comparing the results with history, we find that the last two tests best reflect what happened historically.