00 00 u(t-T/2) u (t + T/2) exp(-jwt) dt was introduced by Ville (1), and its significance with respect to the quality of radar measurements was suggested by Woodward (2), and enlarged upon by Siebert (3). For some time we have been studying the mathematical properties of this function-with the hope of ultimately devising the necessary and sufficient conditions that a function of two variables b...

In this paper we initiate the study of whether or not sparse estimation tasks can be performed efficiently in high dimensions, in the robust setting where an ε-fraction of samples are corrupted adversarially. We study the natural robust version of two classical sparse estimation problems, namely, sparse mean estimation and sparse PCA in the spiked covariance model. For both of these problems, w...

Background MOLLI [1] uses interleaved Look-Locker (LL) blocks for cardiac T1 mapping. Data is fit to the equation A-Bexp (-TI/T1*) to yield an “apparent” T1 (T1*), which is dependent on both the true T1 and imaging parameters. To estimate true T1, a “LL correction” T1est=(B/A-1) T1* [Eq. 1] has been proposed [1,2]. Although this correction can provide reasonable estimates of true T1, we are not...