Closest Segments

Computing Closest Points for Segments

Estimating of hepatic fat amount using MRI proton density fat fraction in a real practice setting

The recently developed magnetic resonance imaging (MRI) proton density fat fraction (PDFF) allows measurement of the fat in all segments of hepatic tissue. However, it is time consuming and inconvenient to measure each segment repeatedly. Moreover, volume of each segment also should be adjusted with arithmetic mean of the selected segments when total amount of liver fat is estimated. Therefore,...

Proximity Problems on Line Segments Spanned by Points

Finding the closest or farthest line segment (line) from a point are fundamental proximity problems. Given a set S of n points in the plane and another point q, we present optimal O(n logn) time, O(n) space algorithms for finding the closest and farthest line segments (lines) from q among those spanned by the points in S. We further show how to apply our techniques to find the minimum (maximum)...

Surface Correspondence and Discrete Harmony Triggers

In this paper, I examine formal properties of surface correspondence and their empirical predictions for languages with partially overlapping harmony patterns. Surface correspondence was introduced as a basis for enforcing feature agreement and disagreement among segments in an output (Walker 2000a). Originating studies focused on consonant harmony, for which surface correspondence offered insi...

The Least-Intensity Feasible Solution for Aperture-Based Inverse Planning in Radiation Therapy

Aperture-based inverse planning (ABIP) for intensity modulated radiation therapy (IMRT) treatment planning starts with external radiation fields (beams) that fully conform to the target(s) and then superimposes sub-fields called segments to achieve complex shaping of 3D dose distributions. The segments’ intensities are determined by solving a feasibility problem. The least-intensity feasible (L...