Neurons in the visual cortex respond selectively to stimulus orientation and spatial frequency. Changes in response amplitudes of these neurons could be the neurophysiological basis of orientation and spatial frequency discrimination. We have estimated the minimum differences in stimulus orientation and spatial frequency that can produce reliable changes in the responses of individual neurons i...

BACKGROUND Studies that are the basis of recommended volume thresholds for CABG surgery are outdated and not reflective of recent advances in the field. This study examines both hospital and surgeon volume-mortality relations for CABG surgery through the use of a population-based clinical data set. METHODS AND RESULTS Data from New York's clinical CABG surgery registry from 1997 to 1999 (tota...

BACKGROUND For oncological evaluations, quantitative radiology gives clinicians significant insight into patients' response to therapy. In regard to the Response Evaluation Criteria in Solid Tumours (RECIST), the classification of disease evolution partly consists in applying thresholds to the measurement of the relative change of tumour. In the case of tumour volumetry, response thresholds hav...

Conventional frequent pattern mining algorithms require some user-specified minimum support, and then mine frequent patterns with support values that are higher than the minimum support. As it is difficult to predict how many frequent patterns will be mined with a specified minimum support, the Top-k mining concept has been proposed. The Top-k Mining concept is based on an algorithm for mining ...

We address the problem of controlling false positive rates in mass-multivariate tests for electromagnetic responses in compact regions of source space. We show that mass-univariate thresholds based on sensor level multivariate thresholds (approximated using Roy's union-intersection principle) are unduly conservative. We then consider a Bonferroni correction for source level tests based on the n...

This study is part of an ongoing research program aimed at understanding how humans perceive the properties and qualities of everyday objects such as rotary switches. This article reports our measurement of detection thresholds for torque vibrations transmitted through a passively-held rotary switch. We show that the torque thresholds are very similar to published displacement thresholds in tha...

Given a set of points S = {x1, . . . , xm} ⊂ R and > 0, we propose and analyze an algorithm for the problem of computing a (1 + )-approximation to the minimum-volume axis-aligned ellipsoid enclosing S . We establish that our algorithm is polynomial for fixed . In addition, the algorithm returns a small core set X ⊆ S , whose size is independent of the number of points m, with the property that ...

Motivated by problems of uncertainty propagation and robust estimation we are interested in computing a polynomial sublevel set of fixed degree and minimum volume that contains a given semialgebraic set K. At this level of generality this problem is not tractable, even though it becomes convex e.g. when restricted to nonnegative homogeneous polynomials. Our contribution is to describe and justi...

A subspace bitrade of type Tq(t, k, v) is a pair (T0, T1) of two disjoint nonempty collections (trades) of k-dimensional subspaces of a v-dimensional space F v over the finite field of order q such that every t-dimensional subspace of V is covered by the same number of subspaces from T0 and T1. In a previous paper, the minimum cardinality of a subspace Tq(t, t + 1, v) bitrade was establish. We ...

Abstract. We study the problem of computing a (1 + )-approximation to the minimum volume enclosing ellipsoid of a given point set S = {p1, p2, . . . , pn} ⊆ Rd. Based on a simple, initial volume approximation method, we propose a modification of Khachiyan’s first-order algorithm. Our analysis leads to a slightly improved complexity bound of O(nd3/ ) operations for ∈ (0, 1). As a byproduct, our ...