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In this paper we describe and analyze a method based on local least square fitting for estimating the normals at all sample points of a point cloud data (PCD) set, in the presence of noise. We study the effects of neighborhood size, curvature, sampling density, and noise on the normal estimation when the PCD is sampled from a smooth curve in(More)
In modular reconfigurable systems, individual modules are capable of limited motion due to blocking and con-nectivity constraints, yet the entire system has a large number of degrees of freedom. The combination of these two facts makes motion planning for such systems exceptionally challenging. In this paper we present two results that shed some light on(More)
We study the problem of landmark selection for landmark-based routing in a network of fixed wireless communication nodes. We present a distributed landmark selection algorithm that does not rely on global clock synchronization, and a companion local greedy landmark-based routing scheme. We assume no node location information, and that each node can(More)
In this paper, we propose to study deformable necklaces --- flexible chains of balls, called beads, in which only adjacent balls may intersect. Such objects can be used to model macro-molecules, muscles, rope, and other 'linear' objects in the physical world. In this paper, we exploit this linearity to develop geometric structures associated with necklaces(More)
In a sensor network information from multiple nodes must usually be aggregated in order to accomplish a certain task. A natural way to view this information gathering is in terms of interactions between nodes that are producers of information, e.g., those that have collected data, detected events, etc., and nodes that are consumers of information , i.e.,(More)
We consider a finite-pool data categorization scenario which requires exhaustively classifying a given set of examples with a limited budget. We adopt a hybrid human-machine approach which blends automatic machine learning with human labeling across a tiered workforce composed of domain experts and crowd workers. To effectively achieve high-accuracy labels(More)
We present an efficient distributed data structure, called the D-SPANNER, for maintaining proximity information among communicating mobile nodes. The D-SPANNER is a kinetic sparse graph spanner on the nodes that allows each node to quickly determine which other nodes are within a given distance of itself, to estimate an approximate nearest neighbor, and to(More)
Combined sewage overflows have created favorable conditions for the establishment of the southern house mosquito, Culex quinquefasciatus Say (Diptera: Culicidae), larvae in natural creeks that would otherwise be unsuitable for the development of this mosquito species. Here, we show the results from a seminatural experiment carried over the three seasons of(More)
[1] Six Arctic Ocean Model Intercomparison Project model simulations are compared with estimates of sea ice thickness derived from pan-Arctic satellite freeboard measurements assessment of six models that differ in numerical methods, resolution, domain, forcing, and boundary conditions, the models generally overestimate the thickness of measured ice thinner(More)