A new family of proximity graphs, called region counting graphs (RCG) is presented. The RCG for a finite set of points in the plane uses the notion of region counting distance introduced by Demaine et al. to characterize the proximity between two points p and q: the edge pq is in the RCG if and only if there is less than or exactly k vertices in a given geometric neighborhood defined by a regio...

We are interested in the problem of how an agent organizes its sensorimotor experiences in order to create a spatial representation. Our approach to solve this problem is the Spatial Semantic Hierarchy (SSH), where multiple levels of spatial representation coexists. At the SSH topological level, space is represented by places and connectivity relation among them. Places are arranged into street...

This is an editorial for the special series.

We present a novel probabilistic model and specification language for spatial relations. Qualitative spatial logics such as RCC are used for representation and reasoning about physical entities. Our probabilistic RCC semantics enables a more expressive representation of spatial relations. We observe that reasoning in this new framework can be hard. We address this difficulty by using a factored...

A novel segmentation algorithm based on the region growing paradigm is presented. Unlike previous segmentation methods, this novel scheme requires neither hand-tuning of parameters nor knowledge about the scene. Instead, the parameter which controls the segmentation is dynamically derived from the data for each region, based on a local quality measure of the region's contour. The algorithm assi...

We present here a new algorithm for segmentation of intensity images which is robust, rapid, and free of tuning parameters. The method, however, requires the input of a number of seeds, either individual pixels or regions, which will control the formation of regions into which the image will be segmented. In this correspondence, we present the algorithm, discuss briefly its properties, and sugg...

The best way to support commonsense reasoning over geographic data is via qualitative spatial reasoning over spatial objects and their relations. The Region Connection Calculus (RCC) (Randell et al. 1992) family is one of the well-known logical languages for formalizing topological relationships that describe commonsense spatial knowledge. In this paper, we modify and extend RCC-8 to propose a ...

Background. While flow convergence methods have been promising for calculating volume flows from color Doppler images, it appears that the velocity threshold used and the transorifice pressure gradient dramatically influence the accuracy of application of the simple hemispheric flow convergence equation for calculation of flow rate. The present in vitro study was performed to determine whether ...

The anatomy of the hippocampal region has been studied intensely in rodents since Cajal (1911) and his pupil, Lorente de N6 (1934), carried out their classic slUdies using the Golgi method. In recent years, the cytoarchitecture and connections of the hippocampal region have been further elucidated by the work of Blackstad (1956, 1958), Raisman et al. (1965, 1966) and Hjorth-Simonsen (1972, 1973...