Planning for self-employment at the beginning of a market economy: evidence from individual data of East German workers

We investigate the plans of individual workers concerning future self-employment in the former German Democratic Republic (East Germany) shortly before the economic, monetary and social union in June/July 1990. Our data base is the Socio-Economic Panel (SOEP) East. We find that the desire to become an entrepreneur is basically determined by individual and household characteristics, including income and asset indicators, and not as much by the current job situation of the individual. Furthermore, we find evidence of barriers to entry which may come from capital market constraints and institutional restrictions. Due to the ordinal nature of the answers, we used the ordinal logit model for estimation. The corresponding stochastic assumptions are tested extensively using pseudo-Lagrange multiplier tests against omitted variables, non-linearity, asymmetry of distribution, and heteroscedasticity. --

Measuring neutron star tidal deformability with Advanced LIGO: a Bayesian analysis of neutron star - black hole binary observations

The discovery of gravitational waves (GW) by Advanced LIGO has ushered us into an era of observational GW astrophysics. Compact binaries remain the primary target sources for LIGO, of which neutron star-black hole (NSBH) binaries form an important subset. GWs from NSBH sources carry signatures of (a) the tidal distortion of the neutron star by its companion black hole during inspiral, and (b) its potential tidal disruption near merger. In this paper, we present a Bayesian study of the measurability of neutron star tidal deformability $\Lambda_\mathrm{NS}\propto (R/M)^{5}$ using observation(s) of inspiral-merger GW signals from disruptive NSBH coalescences, taking into account the crucial effect of black hole spins. First, we find that if non-tidal templates are used to estimate source parameters for an NSBH signal, the bias introduced in the estimation of non-tidal physical parameters will only be significant for loud signals with signal-to-noise ratios $> 30$. For similarly loud signals, we also find that we can begin to put interesting constraints on $\Lambda_\mathrm{NS}$ (factor of 1-2) with individual observations. Next, we study how a population of realistic NSBH detections will improve our measurement of neutron star tidal deformability. For astrophysical populations of $disruptive$ NSBH mergers, we find 20-35 events to be sufficient to constrain $\Lambda_\mathrm{NS}$ within $\pm 25-50\%$, depending on the chosen equation of state. In this we also assume that LIGO will detect black holes with masses within the astrophysical $mass$-$gap$. If the mass-gap remains preserved in NSBHs detected by LIGO, we estimate that $25\%$ $additional$ detections will furnish comparable tidal measurement accuracy. In both cases, we find that the loudest 5-10 events to provide most of the tidal information, thereby facilitating targeted follow-ups of NSBHs in the upcoming LIGO-Virgo runs.Comment: 21 pages, 17 figure

Compact Binary Waveform Center-of-Mass Corrections

We present a detailed study of the center-of-mass (c.m.) motion seen in simulations produced by the Simulating eXtreme Spacetimes (SXS) collaboration. We investigate potential physical sources for the large c.m. motion in binary black hole simulations and find that a significant fraction of the c.m. motion cannot be explained physically, thus concluding that it is largely a gauge effect. These large c.m. displacements cause mode mixing in the gravitational waveform, most easily recognized as amplitude oscillations caused by the dominant (2,$\pm$2) modes mixing into subdominant modes. This mixing does not diminish with increasing distance from the source; it is present even in asymptotic waveforms, regardless of the method of data extraction. We describe the current c.m.-correction method used by the SXS collaboration, which is based on counteracting the motion of the c.m. as measured by the trajectories of the apparent horizons in the simulations, and investigate potential methods to improve that correction to the waveform. We also present a complementary method for computing an optimal c.m. correction or evaluating any other c.m. transformation based solely on the asymptotic waveform data.Comment: 20 pages, 15 figure

Development of a Beam Profile Monitor/Time of Flight setup for HISPEC/DESPEC for FAIR

The Helmholtz Gesellschaft für Schwerionenforschung GmbH will be expanded by the Facility for Antiproton and Ion Research in upcoming years. Different, international collaborations have been formed in order to effectively use the accelerator facilities, which will become available. The collaboration Nuclear Structure, Astrophysics and Reactions deals with the usage of high energetic, radioactive ion beams for nuclear physics experiments. During such experiments it is possible to slow down these ions to energies of 5 to 10 MeV/u to open certain reaction channels. A problem with the slowing down is the introduction of additional energy and spatial straggling as well as a further fragmentation of the original ion beam. To be able to nevertheless select the desired ion, an additional detector is needed directly after the slowing down and before the target. Within the framework of this thesis, such a detector system has been developed and tested. One demand to such a system is a largest possible transparency, not to degrade or even stop the ion beam, which is to be examined. As a solution a design on the basis of an emissive foil has been chosen. Thereby electrons will be emitted out of a thin foil if passed by an ion. These so-called secondary electrons are then accelerated and confined by an electrostatic top-assembly towards the proper detector head where they are position sensitively registered. In this way the ions can be detected indirectly. Using two of such units, the flight path of a single ion can be reconstructed and discriminated against other kinds of ions, additionally. A first prototype was built and continuously developed further. By measurements with radioactive sources its efficiency, spatial and timing resolution was tested. The insights gained therefrom were used to develop a second prototype. With regards to the future use, an as compact as possible, integrated design has been focused on. To investigate the second prototype, a dedicated beamline for detector tests and the simulation of slowed down beams was built at the Cologne FN tandem accelerator. This testbed is open to the collaboration and has already been used successfully

Educational Expansion and its Heterogeneous Returns for Wage Workers

The paper examines the evolution of returns to education in the West German labour market over the last two decades. During this period, graduates from the period of educational expansion in the sixties and seventies entered the labour market and an upgrading of the skill structure took place. In order to tackle the issues of endogeneity of schooling and its heterogeneous returns we apply two estimation methods: Wooldridge’s (2004) approach that relies on conditional mean independence and Garen’s (1984) control function approach that requires an exclusion restriction. For the population of workers from the GSOEP, we find that both approaches produce estimates of average returns to education that decrease until the late 1990s and increase significantly afterwards. In the observation period, the gender gap in returns to education seems to vanish. Furthermore, we find that the so called “baby boomer” cohort has the lowest average return to education in young ages. However, this effect disappears when they become older

Vision systems with the human in the loop

The emerging cognitive vision paradigm deals with vision systems that apply machine learning and automatic reasoning in order to learn from what they perceive. Cognitive vision systems can rate the relevance and consistency of newly acquired knowledge, they can adapt to their environment and thus will exhibit high robustness. This contribution presents vision systems that aim at flexibility and robustness. One is tailored for content-based image retrieval, the others are cognitive vision systems that constitute prototypes of visual active memories which evaluate, gather, and integrate contextual knowledge for visual analysis. All three systems are designed to interact with human users. After we will have discussed adaptive content-based image retrieval and object and action recognition in an office environment, the issue of assessing cognitive systems will be raised. Experiences from psychologically evaluated human-machine interactions will be reported and the promising potential of psychologically-based usability experiments will be stressed

A Low-Effort Recommendation System with High Accuracy - A New Approach with Ranked Pareto-Fronts

In recent studies on recommendation systems, the choice-based conjoint analysis has been suggested as a method for measuring consumer preferences. This approach achieves high recommendation accuracy and does not suffer from the start-up problem because it is also applicable for recommendations for new consumers or of new products. However, this method requires massive consumer input, which causes consumer reluctance. In a simulation study, we demonstrate the high accuracy, but also the high user’s effort for using a utility-based recommendation system using a choice-based conjoint analysiswith hierarchical Bayes estimation. In order to reduce the conflict between consumer effort and recommendation accuracy, we develop a novel approach that only shows Paretoefficient alternatives and ranks them according to the number of dominated attributes. We demonstrate that, in terms of the decision accuracy of the recommended products, the ranked Pareto-front approach performs better than a recommendation system that employs choice-based conjoint analysis. Furthermore, the consumer’s effort is kept low and comparable to that of simple systems that require little consumer input