Assembling and Rearranging Digital Objects in Physical Space with Tongs, a Gluegun, and a Lightsaber

We present an interface for the arrangement of objects in three-dimensional space. Physical motions of the user are mapped to interface commands through tangible props. Tongs move objects freely, a gluegun binds objects together, and a lightsaber breaks these bonds. The experimental interface is implemented on the Responsive Workbench, a semi-immersive 3D computer. We conducted a small user study comparing our approach with the 2D interface of Maya. The results suggest that our system is much faster than Maya for object assembly. Users qualitatively found the system to be far more intuitive than the monitor-based alternative

Eliciting Public Support for Greening the Electricity Mix Using Random Parameter Techniques

With its commitment to double the share of renewable fuels in electricity generation to at least 30% by 2020, the German government has embarked on a potentially costly policy course whose public support remains an open empirical question. Building on household survey data, in this paper we trace peoples‘ willingness-to-pay (WTP) for various fuel mixes in electricity generation, and capture preference heterogeneity among respondents using random parameter techniques. Based on our estimates, we trace out the locus that links the premia charged for specifi c electricity mixes with the fraction of people supporting the policy. Albeit people‘s WTP for a certain fuel mix in electricity generation is positively correlated to the renewable fuel share, our results imply that the current surcharge eff ectively exhausts the fi nancial scope for subsidizing renewable fuels.Green electricity; willingness-to-pay; preference heterogeneity; policy evaluation

On the redistributive effects of Germany's feed-in tariff

The present article assesses the redistributive effects of a key element of German climate change policy, the promotion of renewables in the electricity mix through the provision of a feed-in tariff. The tariff shapes the distribution of households' disposable incomes by charging a levy that is proportional to household electricity consumption, and by financial transfers channeled to households feeding green electricity into the grid. Our study builds on representative household survey data, providing information on various socio demographics, household electricity consumption and ownership of solar facilities. The redistributive effects of the feed-in tariff are evaluated by means of various inequality indices. All the inequality measures indicate that Germany's feed-in tariff is mildly regressive. --Income distribution,redistribution,tax incidence,renewable resources,energy policy

Multilevel Solvers for Unstructured Surface Meshes

Parameterization of unstructured surface meshes is of fundamental importance in many applications of digital geometry processing. Such parameterization approaches give rise to large and exceedingly ill-conditioned systems which are difficult or impossible to solve without the use of sophisticated multilevel preconditioning strategies. Since the underlying meshes are very fine to begin with, such multilevel preconditioners require mesh coarsening to build an appropriate hierarchy. In this paper we consider several strategies for the construction of hierarchies using ideas from mesh simplification algorithms used in the computer graphics literature. We introduce two novel hierarchy construction schemes and demonstrate their superior performance when used in conjunction with a multigrid preconditioner

Two loop mass effects in the static position space QCD-potential

The perturbatively calculable short distance QCD potential is known to two loops including the effect of massive quarks. Recently, a simple approximate solution in momentum space was utilized to obtain the potential in coordinate space. The latter is important in several respects. A comparison with non-perturbative lattice results is feasible in the overlap regime using light $\bar{MS}$ masses. This might be even more promising employing the concept of the force between the heavy color singlet sources, which can be easily derived from the potential. In addition, the better than two percent accuracy bottom mass determination from $\Upsilon$-mesons is sensitive to massive charm loops at the two loop order. We summarize recent results using exact one loop functions and explicit decoupling parametrizations.Comment: Version to appear in Proceedings of QCD0

Permutation Games for the Weakly Aconjunctive μ\mu-Calculus

We introduce a natural notion of limit-deterministic parity automata and present a method that uses such automata to construct satisfiability games for the weakly aconjunctive fragment of the $\mu$-calculus. To this end we devise a method that determinizes limit-deterministic parity automata of size $n$ with $k$ priorities through limit-deterministic B\"uchi automata to deterministic parity automata of size $\mathcal{O}((nk)!)$ and with $\mathcal{O}(nk)$ priorities. The construction relies on limit-determinism to avoid the full complexity of the Safra/Piterman-construction by using partial permutations of states in place of Safra-Trees. By showing that limit-deterministic parity automata can be used to recognize unsuccessful branches in pre-tableaux for the weakly aconjunctive $\mu$-calculus, we obtain satisfiability games of size $\mathcal{O}((nk)!)$ with $\mathcal{O}(nk)$ priorities for weakly aconjunctive input formulas of size $n$ and alternation-depth $k$. A prototypical implementation that employs a tableau-based global caching algorithm to solve these games on-the-fly shows promising initial results

Composite primal/dual √3-subdivision schemes

We present new families of primal and dual subdivision schemes for triangle meshes and 3-refinement. The proposed schemes use two simple local rules which cycle between primal and dual meshes a number of times. The resulting surfaces become very smooth at regular vertices if the number of cycles is ⩾2. The C^1-property is violated only at low-valence irregular vertices, and can be restored by slight modifications of the local rules used. As a generalization, we introduce a wide class of composite subdivision schemes suitable for arbitrary topologies and refinement rules. A composite scheme is defined by a simple upsampling from the coarse to a refined topology, embedded into a cascade of geometric averaging operators acting on coarse and/or refined topologies. We propose a small set of such averaging rules (and some of their parametric extensions) which allow for the switching between control nets associated with the same or different topologic elements (vertices, edges, faces), and show a number of examples, based on triangles, that the resulting class of composite subdivision schemes contains new and old, primal and dual schemes for 3-refinement as well as for quadrisection. As a common observation from the examples considered, we found that irregular vertex treatment is necessary only at vertices of low valence, and can easily be implemented by using generic modifications of some elementary averaging rules

Gesprächsanalytische Rekonstruktion von mündlichen Verhandlungen im Gericht und in alternativen Institutionen des Rechts

No abstract

“Three Long Rows of Empty Shelves” to Fill: Curt Nimuendajú as Collector and Researcher for Ethnological Museums in Germany, 1928-1930

In 1928-29 and 1930, the German-Brazilian anthropologist Curt Nimuendajú was contracted twice by German ethnological institutions (above all, museums) for organizing ethnographic collections and carrying out anthropological research among indigenous peoples; principally Jê-speaking peoples in various regions of today’s Maranhão and Tocantins states in Brazil. This is not only a lesser-known part of Nimuendajú’s biography, but also an example of a kind of academic cooperation difficult to imagine nowadays. The collections, partly destroyed during World War II, are still stored in the ethnological museums of Hamburg, Leipzig, and Dresden, along with a great number of mostly unpublished letters and other documents linked to them. The history of these expeditions offers an opportunity for reflections about the implicit theories involved in contemporary collecting, fieldwork methods, and the style of anthropology practiced. The research reveals influences from German ethnology on the academic environment in Brazil, which later became increasingly independent from this input