Prof. Dr. Thomas Bohlen
Geophysical Institute
Department of Physics
Karlsruhe Institute of Technology

Dr. Stefan Jetschny
Geophysical Institute
Department of Physics
Karlsruhe Institute of Technology

Sven Heider
Geophysical Institute
Department of Physics
Karlsruhe Institute of Technology

Dr. Ekaterina Rykhlinskaya
Steinbuch Centre for Computing (SCC)
Karlsruhe Institute of Technology

Infrastructure projects worldwide often face the same demands of creating short cuts in order to keep up with the increase in public traffic and transportation. One feasible solution is to go underground. With the increasing number and dimensions of such tunneling projects, the use of tunnel boring machines (TBMs) becomes more prevalent. Tunnel boring machines have the potential for automated and continuous drilling of tunnels with low employment of workers at high performance. Nevertheless, the geologic situation along the tunnel trajectory is less predictable in urban areas due to the limited access for geological probing and geophysical measurements. This can results in uncertainties regarding the actual rock type and the spatial location of structures encountered during the tunnel construction. Sudden changes in the geological and geotechnical properties, i.e., at lithological boundaries, fracture zones or ground water bearing soil can be a serious safety threat to the TBM and usually requires specially designed TBMs. Safely predicting geological structures ahead of the tunnel construction can therefore significantly reduce safety risks and prevent expensive down times of the tunnel boring machine.

We use a parallel 3-D elastic finite difference code in order to simulate the complex elastic wave field in models of arbitrary complexity. With respect to the application in the exploration of the tunnel surrounding we observe similar wave field as shown as in Figure 1. On the basis of a random media model that accounts for small and large scale heterogeneities, typical features encountered in a tunnel construction are included, such as a tunnel tube (white), an excavating damaged zone (contour around the tunnel) and a low dipping lithological boundary (straight contour line). While the tunnel tube is extended, i.e. the tunneling is progressing, we perform several wave field simulation to image the exact position of the dipping structure. Each modeling run takes about 4h on 80 cores. The overall goal is to study the complex wave propagation, optimize the measurement geometry and parameters and finally create synthetic field data to develop new imaging and processing methods. Later on, this gained knowledge is directly applied to field cases.

• Bohlen, T., 2002: Parallel 3-D viscoelastic finite-difference seismic modelling, Computers and Geosciences, 28 (8), 887-899.
• Bohlen, T., U. Lorang, W. Rabbel, G. Müller, R. Giese, S. Lüth, and S. Jetschny, 2007: Rayleigh-to-shear wave conversion at the tunnel face - from 3D-FD modeling to ahead-of-drill exploration: Geophysics, 72, T67–T79.
• Jetschny, S., T, Bohlen and A. Kurzmann,2011:Seismic prediction of geological structures ahead of the tunnel using tunnel surface waves, accepted for publication in Geophysical Prospecting

Area: Geophysics

Software:

• SOFI3D

Links:

• SOFI3D
• Seismic Observation in Underground Development (SOUND)

Andy Koch
McCombs School of Business
University of Texas at Austin

Stefan Ruenzi
Chair of International Finance
University of Mannheim

Laura Starks
McCombs School of Business
University of Texas at Austin

Florian Weigert
Chair of International Finance
University of Mannheim

In this paper we investigate the influence of liquidity commonality and systematic fund flows on the investment strategy and performance of mutual funds. We hypothesize that in time periods of low (high) absolute fund netflows, funds - holding shares with high liquidity commonality - perform better (worse) than funds - holding shares with low liquidity commonality. If the netflows of a fund are only weakly correlated with netflows of other funds, we propose that an optimal strategy is to invest in shares with a high degree of liquidity commonality.

• Koch, A.; Ruenzi, S.; Starks, L.; Weigert, F. (2011). Liquidity Commonality, Systematic Fund Flows and Optimal Mutual Fund Behavior, Working Paper, UT Austin and University of Mannheim

Area: Finance

Software:

• Matlab, Stata

Links:

• http://intfin.bwl.uni-mannheim.de/31.html

Hans-Martin von Gaudecker
Fakultät für VWL, Lehrstuhl für Mikroökonometrie
Universität Mannheim

Gemeinsam mit Arthur van Soest (Tilburg) und Erik Wengstrom (Lund) untersuchen wir den Erklärungsgehalt aus ökonomischen Laborexperimenten geschätzter Präferenzparameter in Haushaltsportefeuillewahlmodellen. Zudem vergleichen wir die Verteilungen solcher Präferenzparameter und der Qualität von Entscheidungen in klassischen Laborexperimenten mit Studenten und in der allgemeinen Bevölkerung.

Area: Economics

Software:

• Python, Fortran, Stata

Links:

• http://www.vwl.uni-mannheim.de/gaudecker/research-preferences.htm

Stefan Ruenzi
Chair of International Finance
University of Mannheim

Florian Weigert
Chair of International Finance
University of Mannheim

Theory suggests that investors holding stocks with high sensitivities to extreme market downside movements demand additional compensation. Standard asset pricing models are unable to capture these extreme dependencies because they rely on the lin- ear correlation as their sole dependence measure. We show that extreme dependence structures in the form of upper and lower tail dependence are as important as linear dependence in explaining the cross-sectional variation of expected stock returns. Con- trolling for market beta, stocks with lower (upper) tail dependence have high (low) average returns. These effects are different from known market anomalies and cannot be explained by size, book-to-market, momentum, coskewness or downside beta.

• Ruenzi, S.; Weigert, F. (2011). Extreme Dependence Structures and the Cross-Section of Expected Stock Returns, Working Paper, University of Mannheim

Area: Finance

Software:

• Matlab, Stata

Links:

• http://intfin.bwl.uni-mannheim.de/31.html

Isabel Ruhmer
Center for Doctoral Studies in Economics (CDSE)
Universität Mannheim

Pia Dovern-Pinger
Center for Doctoral Studies in Economics (CDSE)
Universität Mannheim

The aim of this project is to explore consumer behavior in restaurants. Using discrete choice models, we analyze how menu choice is influenced by certain menu- and situational-specific characteristcs. In particular, we investigate whether in addition to prices also the menu design - namely the ordering and grouping of the dishes - influences consumer choice.

First results indicate that consumers tend to be extremeness averse. While overall demand decreases in prices, individuals do not pick alternatives at the lowest or highest end of the price spectrum. Furthermore, the overall number of dishes displayed under a certain sub-category - such as fish or vegetarian - influences a category's choice probability.

As the dataset consists of all bills of a German specialities restaurant over a period of more than seven years, it comprises a huge variety of choices. In total, the data contain menu choices of more than 88,000 individuals who chose among more than 76 alternatives grouped within 6 different categories. As a consequence, the estimations are computationally heavy and could not have been performed without the BwGRID Cluster.

• Ruhmer, Dovern-Pinger: "Do consumers (really) care about prices? Lessons from a restaurant's menu" - to be finished

Area: Economics

Andras Niedermayer
Fakultaet fuer VWL, Lehrstuhl fuer Mikrooekonomische Theorie
Universität Mannheim

Mechanisms where intermediaries charge a commission fee and have the sellers set the price are widely used in practice e.g. by real estate agents, stock brokers, art galleries, or auction houses. We model competition between intermediaries in a dynamic random matching model, where in every period a buyer, a seller, and an intermediary are randomly matched. In any period, every intermediary has a temporary monopoly and designs an exchange mechanism that maximizes his own expected profits. Traders' valuations for the indivisible good depend on their option value of future trade. The following results obtain. First, we show that the intermediary can achieve the highest possible profit with a fee setting mechanism. Second, we characterize when these fees are linear. Third, fee setting is an equilibrium outcome in a dynamic market. Fourth, when the rematching probability increases or, equivalently, the period length decreases, the equilibrium fees become smaller. Our model is applicable to stock brokers and auction houses as intermediaries. It can further explain several of the stylized facts observed in real estate brokerage, such as the 6 percent fee, the relation between listing price and time on market, inefficient free entry, higher prices for houses owned by brokers, and home owners who bought during a boom asking higher prices. We also provide various extensions.

• Andras Niedermayer; Seminar at University of New South Wales; "Fee Setting Intermediaries: On Real Estate Agents, Stock Brokers, and Auction Houses"; online
• Andras Niedermayer; Seminar at Northwestern University; "Fee Setting Intermediaries: On Real Estate Agents, Stock Brokers, and Auction Houses"; online

Area: Economics

Software:

• Matlab, Fortran

Links:

• http://andras.niedermayer.ch/index.php?page=research

Heinz Kredel
Rechenzentrum
Universität Mannheim

The Java Algebra System (JAS) is an object oriented, type safe and multi-threaded approach to computer algebra. JAS provides a well designed software library using generic types for algebraic computations implemented in the Java programming language. The library can be used as any other Java software package or it can be used interactively or interpreted through an jython (Java Python) front end. The focus of JAS is at the moment on commutative and solvable polynomials, Groebner bases and applications. By the use of Java as implementation language JAS is 64-bit and multi-core cpu ready and can make use of distributed computing systems.

• Heinz Kredel; Parallel and distributed Groebner bases computation in JAS; online
• Heinz Kredel; Distributed hybrid Groebner bases computation; online
• Heinz Kredel; Distributed parallel Groebner bases computation; online

Area: Parallel and Distributed Computer Algebra

Software:

• Java Library and jython front-end krum.rz.uni-mannheim.de/jas/download.html

Links:

• http://krum.rz.uni-mannheim.de/jas/

Franz-Josef Pfreundt
Fraunhofer Institut für Techno- und Wirtschaftsmathematik (ITWM)
Fraunhofer Gesellschaft www.itwm.fhg.de

Heinz Kredel
Rechenzentrum
Universität Mannheim www.uni-mannheim.de/rum/

Alfred Geiger
T-Systems, Solutions for Research GmbH
T-Systems www.t-systems.de

Djamshid Tavangarian
Institut für Technische Informatik
Universität Rostock wwwtec.informatik.uni-rostock.de

IPACS wants to define a new basis for benchmarks measuring system performance of distributed systems. The goal is to develop methods of measurement based on new applications, low level, and grid benchmarks, which also allow performance prediction. A further significant element of the new benchmark environment is represented in the usability of the benchmarks. Mechanisms for the automatic installation and execution of benchmarks are being strived for and grid benchmarks, which also allow performance prediction.

• Michael Krietemeyer; Matthias Merz [Eds.]; IPACS-Benchmark - Integrated Performance Analysis of Computer Systems (IPACS) print
• Heinz Kredel; Matthias Merz; 'The Design of the IPACS Distributed Software Architecture' pdf

Area: Performance analysis

Software:

• Benchmark result data base

Links:

• http://www.ipacs-benchmark.org

Bernhard Klingen
Abteilung Volkswirtschaftslehre
Universität Mannheim

Mit einer Mehrebenenanalyse wurden die Präferenzen von EU-Bürgern hinsichtlich der Kompetenzverteilung in der europäischen Sicherheitspolitik untersucht. Im Zentrum standen die konkurrierenden Hypothesen, dass die öffentliche Unterstützung für eine EU- bzw. NATO-Zuständigkeit auf eine Nachfrage nach Sicherheit zurückzuführen ist (Riker-Hypothese) oder dass sie maßgeblich von ideologischen Faktoren (Europhilie, Antiamerikanismus etc.) getragen wird. Als Datengrundlage dienten insbesondere die Umfrageergebnisse der Eurobarometer-Studien EB 62.0 und EB 66.1.

• Klingen, Bernhard; "Is Riker Right? -- Explaining Preferences for Common Defence"; SSRN-Working, 12. August 2009; online.
• Klingen, Bernhard; "A Public Choice Perspective on Defense and Alliance Policy"; in Coyne, Christopher J./Mathers, Rachel L. [Hrsg.], The Handbook on the Political Economy of War; Cheltenham: Edward Elgar Press; 2011; Kap. 17, S. 335-55.
• Klingen, Bernhard; Die Politische Ökonomie der Verteidigungs- und Bündnispolitik; Baden-Baden: Nomos-Verlag; 2011.

Area: Politische Ökonomie

Software:

• Stata