HERMIES-3: A step toward autonomous mobility, manipulation, and perception

HERMIES-III is an autonomous robot comprised of a seven degree-of-freedom (DOF) manipulator designed for human scale tasks, a laser range finder, a sonar array, an omni-directional wheel-driven chassis, multiple cameras, and a dual computer system containing a 16-node hypercube expandable to 128 nodes. The current experimental program involves performance of human-scale tasks (e.g., valve manipulation, use of tools), integration of a dexterous manipulator and platform motion in geometrically complex environments, and effective use of multiple cooperating robots (HERMIES-IIB and HERMIES-III). The environment in which the robots operate has been designed to include multiple valves, pipes, meters, obstacles on the floor, valves occluded from view, and multiple paths of differing navigation complexity. The ongoing research program supports the development of autonomous capability for HERMIES-IIB and III to perform complex navigation and manipulation under time constraints, while dealing with imprecise sensory information

Electrical design optimization of single-mode tunnel-junction-based long-wavelength VCSELs

We present principles for tunnel-juhction (TJ) design optimization for use in intracavity contacted long-wavelength vertical-cavity surface-emitting lasers (LW-VCSELs). Using the WKB approximation, we find that layer thicknesses of 10 nm on the n++ side and 10 mn on the p++ side are large enough to maximize quantum tunneling probability and small enough to yield low optical free-carrier absorption loss. We also conjecture that our experimental test structures and actual devices have far lower active acceptor concentration than we expect based on an analytical model. Finally, we calculate the necessary doping levels to enable single-mode operation of LW-VCSELs and incorporate these conditions into a complete optimized model of our VCSELs. Based on optimal I-V curves, we can expect an increase in single-mode output power from 2 to 3.5 mW

Kinds of Fair Play and Regulation Enforcement: Toward a Better Sports Ethic

It is customary for institutions that organize sporting competitions and events to exercise a considerable degree of authority over the participants. That authority is often manifested in the enforcement of penalties for infringements of fair play. This paper focuses on one concrete case from soccer, although I take the discussion to extend to other sports as well. I argue that not all fair play rules should be enforced by the respective organizing institutions, and that enforcing all of them indiscriminately is a cause of injustice, rather than promoting fairness in sports. I propose a principled way of making the necessary distinction between those fair play rules that are enforceable and those that are not