Johannes Kepler University of Linz

About: Johannes Kepler University of Linz is a education organization based out in Linz, Oberösterreich, Austria. It is known for research contribution in the topics: Computer science & Thin film. The organization has 6605 authors who have published 19243 publications receiving 385667 citations.

On Higher Order Inverse Kinematics Methods in Time-Optimal Trajectory Planning for Kinematically Redundant Manipulators

Abstract: Time-optimal motion control will only find industrial applications if the optimal motions can actually be performed by standard industrial robots. This is not ensured by any optimal motion planning scheme proposed up to now. The limiting aspect rendering all these schemes impractical is the insufficient continuity of the motion trajectories. In this paper, a time-optimal path following along a predefined end-effector path is addressed for kinematically redundant robots, where nonredundant robots are included as special cases. As prerequisite explicit expressions for the higher order inverse kinematics are presented. Kinematic redundancy is resolved and exploited within the trajectory planning using the joint space decomposition and a novel pseudoinverse-based solution of the higher order inverse kinematics. The approaches are demonstrated for two examples of kinematically redundant manipulators performing time-optimal motions along prescribed end-effector paths in compliance with technological constraints. The optimization results are experimentally validated.

Beyond the veil of ignorance: The influence of direct democracy on the shadow economy

Abstract: In this paper we analyze the influence of direct democratic institutions on the size and development of the shadow economies. The framework developed predicts a negative relationship between the degree of direct democracy and the size of the shadow economy. Countries where direct democratic institutions support democratic life are expected to be characterized by a lower informal sector, ceteris paribus. The empirical / econometric investigation of a sample of 56 democracies confirms our core hypothesis and demonstrates that the effect of direct democratic institutions on the shadow economy is negative and quantitatively important; the results are robust and also depend on the interaction of direct democracy with other political institutions, such as district magnitude.

Societal-level versus individual-level predictions of ethical behavior: a 48-society study of collectivism and individualism

Abstract: Is the societal-level of analysis sufficient today to understand the values of those in the global workforce? Or are individual-level analyses more appropriate for assessing the influence of values on ethical behaviors across country workforces? Using multi-level analyses for a 48-society sample, we test the utility of both the societal-level and individual-level dimensions of collectivism and individualism values for predicting ethical behaviors of business professionals. Our values-based behavioral analysis indicates that values at the individual-level make a more significant contribution to explaining variance in ethical behaviors than do values at the societal-level. Implicitly, our findings question the soundness of using societal-level values measures. Implications for international business research are discussed.

Tactor placement in wrist worn wearables

Abstract: Vibro-tactile stimulation has been revealed as a potentially effective means to deliver spontaneous notifications like alerts to recipients that are focused on other tasks (although only at very low bit rates, and depending on the place at which the tactors are placed). This work addresses the issue of the amount of information that can be perceived via stimuli coming from wrist worn tactors, given the recipient is not expecting or attentive to the potential occurrence of an alert. Assuming apparel like wrist watches with embedded tactors to represent the alert delivery platform, we investigate - respecting physiognomical properties of tactile perception-the effectiveness of different tactor placements. We compare the case of embedding 4 tactors underneath the “face” of the wrist watch, against the case of embedding it into the wristband (“wrist”). A user study of 1,823 trials has been conducted involving recipients exposed to different levels of engagement in a certain activity. The experiments show, that the amount of information perceived via spontaneous tactile alerts ranges from 1.90–2.49 bits at low, to 1.59–2.41 bits at high levels of engagement. The “wrist” tactor placement achieves a 41.6 % higher perception bit rate than the “face” tactor placement.