The short-term fluctuation in regular grid threshold static fields is commonly determined from repeated observations of a number of threshold points. In this study we estimated the short-term fluctuation from a single determination of the field. Sixty-two eyes of 62 patients were tested, using three consecutive repetitions of a Humphrey 24-2 full threshold program. The resulting grid patterns w...

Inspired by the idea that threshold surface always intersects the image surface at high gradient points, an active surfacebased adaptive thresholding algorithm is proposed to get the binarized result. In this model, the external force is designed to be repulsive from the image surface, thus at the equilibrium state the active surface tends to cover the supporting points of high gradient with sm...

We report the desorption of a chemisorbed polyatomic adsorbate from a transition metal surface by a beam of neutral, energetic Ar atoms. From direct measurement of the threshold energy for collision-induced desorption we calculate the surface–adsorbate bond energy. The absolute cross sections for NH3 desorption at one-quarter of a monolayer coverage were measured for Ar beam energies up to ;3 e...

Given a population with m heterogeneous subgroups, a method is developed for determining minimal vaccine allocations to prevent an epidemic by setting the reproduction number to 1. The framework is sufficiently general to apply to several epidemic situations, such as SIR, SEIR and SIS models with vital dynamics. The reproduction number is the largest eigenvalue of the linearized system round th...

2-D threshold function f is a function defined on the integer interior of a rectangular area [0, m] × [0, n] on a plane and takes values from the set {0, 1} such that there is a straight line separating the pre-images f −1 (0) and f −1 (1). For the number of such functions only asymptotic bounds were known. We give an exact formula for the number of 2-D threshold functions and derive an asympto...

The multiple-look notion holds that the difference limen (DL) decreases with multiple observations. We investigated this notion for temporal discrimination in isochronous sound sequences. In Experiment 1, we established a multiple-look effect when sequences comprised nine standard time intervals (S) followed by an increasing number of comparison time intervals (C), but no multiple-look effect w...

We examined the activity pattern of low-threshold motor units in the human trapezius muscle during contractions of 10 min duration. Three procedures were applied in sequence: 1) static contraction controlled by maintaining a constant low level of the surface electromyogram (EMG)-detected root-mean-square signal, 2) a manipulation task with mental concentration, and 3) copying a text on a word p...

This paper describes a novel method for creating surfaces models from distorted volume datasets in 3D computed tomography (3D-CT). As all 3D-CT datasets are prone to artefacts, especially geometry extraction may produce erroneous surface models if a single global threshold is used. Depending on the selected threshold either the area of material is thickened because ambient noise is added (thres...