We introduce a new approach for exploration based on the concept of frontiers, regions on the boundaly between open space and unexplored space. By moving to new frontiers, a mobile robot can extend its map into new territory until the entire environment has been explored. We describe a method for detecting frontiers in evidence grids and navigating to these frontiers. We also introduce a techni...

The observational consequences of the merger scenario for massive star formation are explored and contrasted with the gradual accumulation of mass by accretion. In high density proto-star clusters, envelopes and disks provide a viscous medium which can dissipate the kinetic energy of passing stars, greatly enhancing the probability of capture. Protostellar mergers may produce high luminosity in...

The microscopic structure and anisotropy of plant cell walls greatly influence the mechanical properties, morphogenesis, and growth of plant cells and tissues. The microscopic structure and properties of cell walls are determined by the orientation and mechanical properties of the cellulose microfibrils and the mechanical properties of the cell wall matrix. Viewing the shape of a plant cell as ...

Capillarity can be used to direct anisotropic colloidal particles to precise locations and to orient them by using interface curvature as an applied field. We show this in experiments in which the shape of the interface is molded by pinning to vertical pillars of different cross-sections. These interfaces present well-defined curvature fields that orient and steer particles along complex trajec...

Cells in the cat's striate cortex show marked specificity in their responses to restricted retinal stimulation (Hubel & Wiesel, 1959, 1962). The most effective stimulus shapes are long narrow rectangles of light ('slits'), dark bars against a light background ('dark bars'), and straight-line borders separating areas of different brightness ('edges'). A given cell responds vigorously when an app...

[1] Meteor Crater provides a rare opportunity to study impact deformation of sedimentary target rocks and isolate those features from preexisting tectonic deformation and impact-generated reactivation of preexisting tectonic features. This study reports over 2500 new measurements of orientations of bedding, faults, and fractures in crater walls and in surrounding bedrock. Target rocks are chara...

With the increased awareness of energy consumption as well as the environmental impact of building operations, architects, designers and planners are required to place more consideration on sustainability and energy performance of the building. To ensure most of those considerations are reflected in the building performance, critical design decisions should be made by key stakeholders early dur...

Many of the neurons in early visual cortex are selective for the orientation of boundaries defined by first-order cues (luminance) as well as second-order cues (contrast, texture). The neural circuit mechanism underlying this selectivity is still unclear, but some studies have proposed that it emerges from spatial nonlinearities of subcortical Y cells. To understand how inputs from the Y-cell p...

To construct three dimensional models from range data, the simultaneous registration of multiple views must be accomplished. There exists a natural hierarchy between the local problem of aligning two views and the global problem of maintaining a consistent network of relative orientation and positions between views. Our paper addresses the global problem, where we compute orientation and positi...