Abstract – Crossbar-based switches are commonly used to implement routers with throughputs up to about 1 Tb/s. The advent of crossbar scheduling algorithms that provide strong performance guarantees now makes it possible to engineer systems that perform well, even under extreme traffic conditions. Up to now, such performance guarantees have only been developed for crossbars that switch cells rather than variable length packets. Cell-based schedulers may fail to deliver the expected performance guarantees when used in routers that forward packets of variable length. We show how to obtain performance guarantees for asynchronous crossbars that are directly comparable to the performance guarantees previously available only for synchronous, cell-based crossbars. In particular we define derivatives of the Group by Virtual Output Queue (GVOQ) scheduler of Chuang et. al. and the Least Occupied Output First Scheduler of Krishna et. al. and show that both can provide strong performance guarantees in systems with speedups ≥2. We also introduce a new class of segment-based switches that can deliver strong performance guarantees with small buffer requirements and no bandwidth fragmentation. 1.

A novel approach to the automatic extraction of geological faults from three-dimensional (3-D) seismic data is described, and qualitative and quantitative comparisons of manually and automatically picked fault geometries interpreted from both high and medium quality 3-D seismic datasets are presented. An algorithm has been developed that allows semiautomated identification, extraction, and modeling of fault surfaces imaged in 3-D seismic datasets. Based on a multistage approach, the algorithm operates initially at a small spatial scale, identifying local discontinuities in the seismic horizons, and then gradually considers larger and larger segments of fault surfaces until a set of complete fault surfaces are identified. A large portion of the work involves merging of segments of fault surfaces, performed using a highest confidence first (HCF) stratagem, taking into consideration the context of the resultant fault geometry. We show that results from the automated fault picker compare favorably with a manually labeled set of faults surfaces interpreted from a high-quality dataset. Last, we present an estimate of the savings in human operator time that can be made by using the automated approach, indicating savings of multiple person-days for the multigigabyte datasets that typify the petroleum industry.

A goal of human-robot interaction is to expand the capability of human beings so that they can control multiple robots simultaneously. This provides leverage for human attention beyond single robot interaction. The number of such robots that can be operated is called the fan-out of a human-robot team. We define the concepts of neglect-tolerance as a measure of autonomy and interaction-effort as a measure of required human attention. A model for fan-out is presented that predicts a human's ability to control multiple robots. We validate this model using robot simulations and user studies. Using the validated model we demonstrate enhanced task performance on physical robots as predicted by the model.