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On Strong Centerpoints
"... Let P be a set of n points in Rd and F be a family of geometric objects. We call a point x ∈ P a strong centerpoint of P w.r.t F if x is contained in all F ∈ F that contains more than cn points from P, where c is a fixed constant. A strong centerpoint does not exist even when F is the family of half ..."
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Let P be a set of n points in Rd and F be a family of geometric objects. We call a point x ∈ P a strong centerpoint of P w.r.t F if x is contained in all F ∈ F that contains more than cn points from P, where c is a fixed constant. A strong centerpoint does not exist even when F is the family
The Vector Field Histogram  Fast Obstacle Avoidance For Mobile Robots
 IEEE JOURNAL OF ROBOTICS AND AUTOMATION
, 1991
"... A new realtime obstacle avoidance method for mobile robots has been developed and implemented. This method, named the vector field histogram(VFH), permits the detection of unknown obstacles and avoids collisions while simultaneously steering the mobile robot toward the target. The VFH method uses a ..."
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Cited by 470 (23 self)
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A new realtime obstacle avoidance method for mobile robots has been developed and implemented. This method, named the vector field histogram(VFH), permits the detection of unknown obstacles and avoids collisions while simultaneously steering the mobile robot toward the target. The VFH method uses a twodimensional Cartesian histogram gridas a world model. This world model is updated continuously with range data sampled by onboard range sensors. The VFH method subsequently employs a twostage datareduction process in order to compute the desired control commands for the vehicle. In the first stage the histogram gridis reduced to a onedimensional polar histogramthat is constructed around the robot's momentary location. Each sector in the polar histogramcontains a value representing the polar obstacle densityin that direction. In the second stage, the algorithm selects the most suitable sector from among all polar histogram sectors with a low polar obstacle density, and the steering of the robot is aligned with that direction. Experimental results from a mobile robot traversing densely cluttered obstacle courses in smooth and continuous motion and at an average speed of 0.6 0.7m/sec demonstrate the power of the VFH method.
CENTERPOINT MODEL OF DEFORMABLE
"... Abstract: Centerpoint model of deformable surface for segmentation of 3D images is presented. Mobility of each node, element composing the surface, is constrained in the model to one direction. Also an original formula for image influence computation is proposed. The model aims at algorithm simplif ..."
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Abstract: Centerpoint model of deformable surface for segmentation of 3D images is presented. Mobility of each node, element composing the surface, is constrained in the model to one direction. Also an original formula for image influence computation is proposed. The model aims at algorithm
Multiresolution, objectoriented fuzzy analysis of remote sensing data for GISready information
 ISPRS Journal of Photogrammetry and Remote Sensing
"... for GISready information ..."
Measurement and Correction of Systematic Odometry Errors in Mobile Robots
 IEEE Transactions on Robotics and Automation
, 1996
"... Odometry is the most widely used method for determining the momentary position of a mobile robot. In most practical applications odometry provides easily accessible realtime positioning information inbetween periodic absolute position measurements. The frequency at which the (usually costly and/or ..."
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Cited by 172 (6 self)
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Odometry is the most widely used method for determining the momentary position of a mobile robot. In most practical applications odometry provides easily accessible realtime positioning information inbetween periodic absolute position measurements. The frequency at which the (usually costly and/or timeconsuming) absolute measurements must be performed depends to a large degree on the accuracy of the odometry system. This paper introduces practical methods for measuring and reducing odometry errors that are caused by the two dominant error sources in differentialdrive mobile robots: (a) uncertainty about the effective wheelbase and (b) unequal wheel diameters. These errors stay almost constant over prolonged periods of time. Performing an occasional calibration as proposed here will increase the robot's odometric accuracy and reduce operation cost because an accurate mobile robot requires fewer absolute positioning updates. Many manufacturers or endusers calibrate their robots, usually in a timeconsuming and nonsystematic trial and error approach. By contrast, the method described in this paper is systematic, provides nearoptimal results, and it can be performed easily and without complicated equipment. Experimental results are presented that show a consistent improvement of at least one order of magnitude in odometric accuracy (with respect to systematic errors) for a mobile robot calibrated with our method. Some parts of the material in this paper were presented at the 1995 International Conference on Intelligent Robots and Systems (IROS '95), Pittsburgh, Pennsylvania, August 59, 1995; some other parts were presented at the 1995 SPIE Conference on Mobile Robots, Philadelphia, October 2226, 1995. 2 1.
Exploiting Redundancy in Question Answering
 In Proceedings of SIGIR
, 2001
"... Our goal is to automatically answer brief factual questions of the form "When was the Battle of Hastings?" or "Who wrote The Wind in the Willows?". Since the answer to nearly any such question can now be found somewhere on the Web, the problem reduces to finding potential answers ..."
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Cited by 125 (11 self)
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Our goal is to automatically answer brief factual questions of the form "When was the Battle of Hastings?" or "Who wrote The Wind in the Willows?". Since the answer to nearly any such question can now be found somewhere on the Web, the problem reduces to finding potential answers in large volumes of data and validating their accuracy. We apply a method for arbitrary passage retrieval to the first half of the problem and demonstrate that answer redundancy can be used to address the second half. The success of our approach depends on the idea that the volume of available Web data is large enough to supply the answer to most factual questions multiple times and in multiple contexts. A query is generated from a question and this query is used to select short passages that may contain the answer from a large collection of Web data. These passages are analyzed to identify candidate answers. The frequency of these candidates within the passages is used to "vote" for the most likely answer. The ...
A Logic MetaProgramming Approach to Support the CoEvolution of ObjectOriented Design and Implementation
, 2001
"... this documentation uptodate. This problem is clearly visible in objectoriented frameworks. An objectoriented framework is defined as a set of classes which embody an abstract design for solutions to a family of related problems [JF88]. It can be seen as a skeleton that implements an abstract app ..."
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Cited by 128 (13 self)
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this documentation uptodate. This problem is clearly visible in objectoriented frameworks. An objectoriented framework is defined as a set of classes which embody an abstract design for solutions to a family of related problems [JF88]. It can be seen as a skeleton that implements an abstract application for some specific domain. In order to get a working application, this skeleton then has to be fitted with the specific outward appearance. This is called instantiating the framework
Templates for Convex Cone Problems with Applications to Sparse Signal Recovery
, 2010
"... This paper develops a general framework for solving a variety of convex cone problems that frequently arise in signal processing, machine learning, statistics, and other fields. The approach works as follows: first, determine a conic formulation of the problem; second, determine its dual; third, app ..."
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Cited by 124 (7 self)
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This paper develops a general framework for solving a variety of convex cone problems that frequently arise in signal processing, machine learning, statistics, and other fields. The approach works as follows: first, determine a conic formulation of the problem; second, determine its dual; third, apply smoothing; and fourth, solve using an optimal firstorder method. A merit of this approach is its flexibility: for example, all compressed sensing problems can be solved via this approach. These include models with objective functionals such as the totalvariation norm, ‖W x‖1 where W is arbitrary, or a combination thereof. In addition, the paper also introduces a number of technical contributions such as a novel continuation scheme, a novel approach for controlling the step size, and some new results showing that the smooth and unsmoothed problems are sometimes formally equivalent. Combined with our framework, these lead to novel, stable and computationally efficient algorithms. For instance, our general implementation is competitive with stateoftheart methods for solving intensively studied problems such as the LASSO. Further, numerical experiments show that one can solve the Dantzig selector problem, for which no efficient largescale solvers exist, in a few hundred iterations. Finally, the paper is accompanied with a software release. This software is not a single, monolithic solver; rather, it is a suite of programs and routines designed to serve as building blocks for constructing complete algorithms. Keywords. Optimal firstorder methods, Nesterov’s accelerated descent algorithms, proximal algorithms, conic duality, smoothing by conjugation, the Dantzig selector, the LASSO, nuclearnorm minimization.
Where am I?” Sensors and methods for mobile robot positioning
, 1996
"... Please direct all inquiries to Johann Borenstein. ..."
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Cited by 112 (1 self)
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Please direct all inquiries to Johann Borenstein.
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