Presence-dependent Performance Differences Between Virtual Simulations And Miniature Worlds

The purpose of simulation is to avoid reality-based constraints by the implemen-tation of a synthetic model. Based on this advantage, interactive simulations have conquered all areas of applications from acquisition, and training, to research. Simulation results are transferred in many ways into reality and conclusions are drawn from the simulation to the application. Many anecdotal observations on human-in-the-loop simulations have shown a significant difference in actor behavior between simulations and reality-based applications. It seems that the factors that makes simulation so attractive, namely the absence of constraints and especially of imminent danger for persons and equipment, influence the behavior and thereby the performance of the user. These differences between simulation and reality may lead to false conclusions based on simulation results. The concept of perceiving a simulation as real and of being in the simulation is called sense of presence. This psychological construct can also be described as level of disbelief towards the simulation. Hence, differences in behavior are based on such users assessment of a simulation and subsequently are supposed to be mediated by a difference in presence. This research established significant differences in presence and performance between a simulation and a miniature-world teleoperation task. Presence and performance changed in identical tasks due to the application type and the connected danger to the robot. Also, the results supported a negative relationship between presence and performance: presence increased in the miniature-world and affected performance so that performance decreased. The causal relationship of application type→ presence→ performance was established and demands the examination of simulation based results with respect to the perceived danger to equipment, before they are transferred into the real application

Granular Rough Sphere in a Low-Density Thermal Bath

We study the stationary state of a rough granular sphere immersed in a thermal bath composed of point particles. When the center of mass of the sphere is fixed the stationary angular velocity distribution is shown to be Gaussian with an effective temperature lower than that of the bath. For a freely moving rough sphere coupled to the thermostat via inelastic collisions we find a condition under which the joint distribution of the translational and rotational velocities is a product of Gaussian distributions with the same effective temperature. In this rather unexpected case we derive a formula for the stationary energy flow from the thermostat to the sphere in accordance with Fourier law

Compiling Geometric Algebra Computations into Reconfigurable Hardware Accelerators

Geometric Algebra (GA), a generalization of quaternions and complex numbers, is a very powerful framework for intuitively expressing and manipulating the complex geometric relationships common to engineering problems. However, actual processing of GA expressions is very compute intensive, and acceleration is generally required for practical use. GPUs and FPGAs offer such acceleration, while requiring only low-power per operation. In this paper, we present key components of a proof-of-concept compile flow combining symbolic and hardware optimization techniques to automatically generate hardware accelerators from the abstract GA descriptions that are suitable for high-performance embedded computing

Mean Field theory for a driven granular gas of frictional particles

We propose a mean field (MF) theory for a homogeneously driven granular gas of inelastic particles with Coulomb friction. The model contains three parameters, a normal restitution coefficient $r_n$, a maximum tangential restitution coefficient $r_t^m$, and a Coulomb friction coefficient $\mu$. The parameters can be tuned to explore a wide range of physical situations. In particular, the model contains the frequently used $\mu \to \infty$ limit as a special case. The MF theory is compared with the numerical simulations of a randomly driven monolayer of spheres for a wide range of parameter values. If the system is far away from the clustering instability ($r_n \approx 1$), we obtain a good agreement between mean field and simulations for $\mu=0.5$ and $r_t^m=0.4$, but for much smaller values of $r_n$ the agreement is less good. We discuss the reasons of this discrepancy and possible refinements of our computational scheme.Comment: 6 pages, 3 figures (10 *.eps files), elsart style (macro included), in Proceedings of the International Conference "Statistical Mechanics and Strongly Correlated Systems", University of Rome "La Sapienza" (Italy), 27-29 September 199

Mögliche Auswirkungen des neu vom Bundesverfassungsgericht in Recht auf Vergessen I und Recht auf Vergessen II eingeführten Konzepts auf das Strafrecht

Dieser Beitrag ist mit Zustimmung des Rechteinhabers (De Gruyter) frei zugänglich.Peer Reviewe