United we stand..divided we fall: Political opposition fragmentation post-Mubarak

This thesis examines the causal factors behind the persistence of opposition fragmentation after the toppling of Mubarak and the collapse of the regime’s throbbing heart, the security apparatus. This is due to the importance of opposition unification not only in the toppling of autocrats but also in the success of any transition towards democracy. More urgency is brought to the puzzle due to the specific nature of the transitional period that was more in favor of different political forces compared to previous periods. This argues that three causal factors were behind the re-fragmentation of the opposition post-Mubarak: the continuation of regime manipulation by the SCAF, the failure of cooperation between youth movements and political parties, and the polarization between Islamists and Secularists

More than a Million Ways to Be Pushed: A High-Fidelity Experimental Dataset of Planar Pushing

Pushing is a motion primitive useful to handle objects that are too large, too heavy, or too cluttered to be grasped. It is at the core of much of robotic manipulation, in particular when physical interaction is involved. It seems reasonable then to wish for robots to understand how pushed objects move. In reality, however, robots often rely on approximations which yield models that are computable, but also restricted and inaccurate. Just how close are those models? How reasonable are the assumptions they are based on? To help answer these questions, and to get a better experimental understanding of pushing, we present a comprehensive and high-fidelity dataset of planar pushing experiments. The dataset contains timestamped poses of a circular pusher and a pushed object, as well as forces at the interaction.We vary the push interaction in 6 dimensions: surface material, shape of the pushed object, contact position, pushing direction, pushing speed, and pushing acceleration. An industrial robot automates the data capturing along precisely controlled position-velocity-acceleration trajectories of the pusher, which give dense samples of positions and forces of uniform quality. We finish the paper by characterizing the variability of friction, and evaluating the most common assumptions and simplifications made by models of frictional pushing in robotics.Comment: 8 pages, 10 figure