Parallel MRI techniques utilize the inherent encoding effect of receiver coil sensitivity for complementing gradient-driven Fourier encoding. As a consequence of this hybrid encoding approach, parallel techniques require advanced reconstruction algorithms beyond mere Fourier transform. Generally, taking coil sensitivity into account renders the reconstruction problem more complex and numericall...

Uncovering the right skills behind question items is a difficult task. It requires a thorough understanding of the subject matter and of the cognitive factors that determine student performance. The skills definition, and the mapping of item to skills, require the involvement of experts. We investigate means to assist experts for this task by using a data driven, matrix factorization approach. ...

In Cle93] we describe a new mapping of sparse matrices to the processors of a distributed memory parallel computer, called the sparse torus wrap mapping (STWM), designed to reduce the volume of interprocessor communication during the Cholesky factorization A = LL T. The mapping combines the advantages of the so-called dense torus wrap mapping (DTWM) Ash91b] developed for dense matrix factorizat...

Supervised attribute relevance detection using cross-comparisons (SARDUX), a recently proposed method for data-driven metric learning, is extended from dimension-weighted Minkowski distances to metrics induced by a data transformation matrix Ω for modeling mutual attribute dependence. Given class labels, parameters of Ω are adapted in such a manner that the inter-class distances are maximized, ...

Consider two maps having the same spatial extent and the same mapping categories but where each map is subject to classi ̄cation error. An overlay of the maps yields a (dis)similarity matrix whose (i; j)-entry is the areal proportion placed into category i by the ̄rst map and into category j by the second map. Patil and Taillie (2003) have proposed a latent truth model which speci ̄es the dissimi...

In this paper we fully describe all tropical linear mappings in the tropical pro-jective plane TP 2 , that is, maps from the tropical plane to itself given by tropical multiplication by a 3 × 3 matrix A with entries in T. First we will allow only real entries in the matrix A and, only at the end of the paper, we will allow some of the entries of A equal −∞. The mapping fA is continuous and piec...

A new method for inversion of rectangular matrices in a multivariate polynomial ring with coefficients in a field is explained. This method requires that the polynomial matrix satisfies the one-to-one mapping criteria defined in [1].

Physical mapping is an important problem in computational biology. Physical mapping is used in largescale sequencing of DNA as well as for locating genes. We study the Radiation Hybrid (RH) problem, i.e., the algorithmic part of a physical mapping method called RH mapping. In order to obtain an algorithm for the RH problem, we consider the MATRIX-TO-LINE problem, which is of obvious independent...

The Matrix-To-Line problem is that of, given an n × n symmetric matrix D, finding an arrangement of n points on the real line such that the so obtained distances agree as well as possible with the by D specified distances, w.r.t. the max-norm. The Matrix-To-Line problem has previously been shown to be NP-complete [11]. We show that it can be approximated within 2, but not within 7/5−δ for any δ...