The deep quench obstacle problem models phase separation at low temperatures. During phase separation, domains of high and low concentration are formed, then coarsen or grow in average size. Of interest is the time dependence of the dominant length scales of the system. Relying on recent results by Novick-Cohen & Shishkov [16], we demonstrate upper bounds for coarsening for the deep quench obst...

Abstract We prove an existence result for obstacle problems related to convection-diffusion parabolic equations with singular coefficients in the convective term. Our operator is not coercive, function time-dependent irregular, and lower-order term belong a borderline mixed Lebesgue-Marcinkiewicz space.

GOLDMAN, SUSAN R., and VARNHAGEN, CONNIE K. Comprehension of Stories with No-Obstacle and Obstacle Endings. CHILD DEVELOPMENT, 1983, 54, 980-992. Comprehension of stories with and without obstacles to goal attainment was examined. 16 secondand fifth-grade students and 16 adults listened to and read single-episode stories in which (1) the protagonist met the episode goal (no-obstacle ending) and...

Crossing moving obstacles requires different space-time adjustments compared with stationary obstacles. Our aim was to investigate gait spatial and temporal parameters in the approach and crossing phases of a moving obstacle. We hypothesized that obstacle speed affects gait parameters, which allow us to distinguish locomotor strategies. Ten young adults walked and stepped over an obstacle that ...

Reliable detection of non-traversable hazards is a key requirement for off-road autonomous navigation. Under the Army Research Laboratory (ARL) Collaborative Technology Alliances (CTA) program, JPL has evaluated the performance of seven obstacle detection algorithms on a General Dynamics Robotic Systems (GDRS) surveyed obstacle course containing 21 obstacles. Stereo imagery was collected from a...

This paper first presents a discussion of the reasoning and method for combining neural networks and fuzzy logic. The problem of moving a robotic arm in the presence of an obstacle is discussed. Several neuro-fuzzy controllers are trained using sample data obtained from a human’s control of a robotic arm. Their performance is quantified and compared. It is shown that the definition of the fuzzy...

BACKGROUND AND PURPOSE Obstacle crossing is compromised following stroke. The purpose of this study was to quantify modifications during obstacle clearance following stroke. SUBJECTS Twelve subjects with stroke and 12 subjects without stroke participated in the study. METHODS Kinematic variables were measured while participants crossed a 4-cm-high obstacle. Subjects with stroke walked at a ...