This paper describes a strategy for vectorizing 3D scenes with proper occlusion. Given a collection of curves derived from 3D geometry (silhouettes, isolines, material boundaries, etc.), we produce a 2D vector image that partitions the image plane into a planar map of solid shaded regions. The method is agnostic to surface representation, handling for instance curves obtained from polygonal, NURBS or subdivision surfaces. The output likewise supports curve segments of arbitrary parametric type. Our key observation is that the spatial hierarchy used to accelerate curve-curve intersections provides the fundamental representation of the planar map itself. This approach provides geometric flexibility, since general curve-curve intersection problems are replaced with simpler curve-line intersection. Simultaneously, it provides robustness since cells of the spatial hierarchy define a well-defined planar map, even in the presence of numerical errors. For instance, it automatically handles "curve soup" where segment endpoints are not explicitly connected in the input file. The method scales to a large number of primitives, and is output sensitive: it resolves intersections only up to a user-defined precision—while still providing topologically valid output. We evaluate the method on a collection of challenging tests, showing that it is both more robust and orders of magnitude more efficient than existing curve arrangement techniques, such as those found in CGAL.

Previous research suggests that intonation is a particularly challenging aspect of L2 speech learning.While most research focuses on speech production, we widen the focus and study the perception of intonation by L2 learners.We investigate whether advanced German learners of English have knowledge of the appropriate English intonation patterns in a narrative context with different sentence types (e.g.statements, questions).The results of a tonal pattern selection task indicate that learners (n=20) performed similar to British English controls (n=25) for some sentence types (e.g.statements, yes/no-questions), but performed significantly worse than the control group in the case of open and closed tag questions and the expression of sarcasm.The results can be explained by the fact that tag questions are the only sentence type investigated that does not exist in the learners' L1, and sarcasm is not represented syntactically.This suggests that L1 influence can partly account for why some intonation patterns are more challenging than others, and that contextualized knowledge of the intonation patterns of the target language rather than knowledge of intonation patterns in isolation is crucial for the successful L2 learning of intonation.

Previous accounts of speech rhythm focus mainly on duration. For example, the normalised Pairwise Variability Index for vocalic intervals (nPVI-V) quantifies relative duration differences between successive vocalic intervals. Prototypical syllabletiming is characterised by small differences in duration, prototypical stress-timing by large differences. However, differences in f0 between vocalic intervals are thought to influence the perception of duration. This paper (1) quantifies the influence of differences in f0 on perceived duration in a perception experiment, and (2) suggests a modified PVI (nPVI-V(dur*f0)) that takes account of this influence. The new nPVI-V(dur*f0) is then applied to a speech corpus of (stress-timed) British English and (syllable-timed) Indian English. The results are compared to the application of the old nPVI-V, which takes into account duration only, to the same data set.

Production of nursery crops in the US is accomplished in container- and field-growing conditions, with propagation and seedling-rearing carried out in greenhouses. The USDA, NASA and the ANLA have collaborated to develop an automated in-field container-handling system for reducing dependence on foreign labor while also increasing productivity. A first-generation system was developed at CMU, capable of automatically lifting and conveying plants from the ground onto trailers, and vice-versa. The system is capable of handling a vast array of container-designs from different manufacturers, and spans the size-range from #1 to #5 (approximate equivalence to gallons). The system is designed to handle 45,000 containers per 8-hour day with one to two operators. Testing and a new design are currently underway, with as-built designs and experimental results for the first prototype's performance presented.

Urban settings represent a challenging environment for teleoperated and autonomous robot systems. We present a new design for a highly terrain adaptable robot system, detailing the major mechanical, electrical and control systems. The Pandora robot system is a tracked robot system with self-contained computing, power and wireless communications systems. A sensor suite including stereoscopic and panospheric cameras, light-strippers and acoustic sonar-ring(s) allow the system to operate autonomously. Individually adjustable track-modules give Pandora extreme mobility in natural (vegetation, soils) and man-made (roads, steps) outdoor environments as well as indoor arenas (sewers, staircases, etc.). Locomotion was shown successfully over various extreme terrains, including reconfiguration to best suit the terrain and enable future sensor-supported autonomous operations.