We propose a procedure for building symmetric positive definite band preconditioners for large-scale symmetric, possibly indefinite, linear systems, when the coefficient matrix is not explicitly available, but matrix-vector products involving it can be computed. We focus on linear systems arising in Newton-type iterations within matrix-free versions of projected methods for bound-constrained no...

Recently Chen and Mangasarian proposed a class of smoothing functions for linear/nonlinear programs and complementarity problems that uniies many previous proposals. Here we study a non-interior continuation method based on these functions in which, like interior path-following methods, the iterates are maintained to lie in a neighborhood of some path and, at each iteration, one or two Newton-t...

This threats document provides a detailed analysis of the security threats relevant to the Next Steps in Signaling (NSIS) protocol suite. It calls attention to, and helps with the understanding of, various security considerations in the NSIS Requirements, Framework, and Protocol proposals. This document does not describe vulnerabilities of specific parts of the NSIS protocol suite.

A consistent result in the evaluation of group-delivered intervention to promote social reciprocity in children with PDDs is that outcome data are inconclusive. Lack of robust evidence of efficacy confounds understanding of these interventions and their value to the field. It is conceivable that the construct of impaired social reciprocity in PDD presents unique circumstances that require speci...

RSVP version 1 has been designed for optimally support multicast. However, in reality multicast is being used much less frequently than anticipated. Still, even for unicast (one sender, one receiver) communication, full−fledged multicast−enabled RSVP signaling must be used. As pointed out in the NSIS requirement draft, multicast would not be necessarily required for an NSIS signaling protocol. ...

This paper presents a new context for using the sparse Broyden update method to solve systems of nonlinear equations. The setting for this work is that a Newton-like algorithm is assumed to be available which incorporates a workable strategy for improving poor initial guesses and providing a satisfactory Jacobian matrix approximation whenever required. The total cost of obtaining each Jacobian ...

We consider distributed convex optimization problems originated from sample average approximation of stochastic optimization, or empirical risk minimization in machine learning. We assume that each machine in the distributed computing system has access to a local empirical loss function, constructed with i.i.d. data sampled from a common distribution. We propose a communication-efficient distri...

We present in this paper a fully implicit finite element method tailored for the numerical modeling of inextensible fluidic membranes in a surrounding Newtonian fluid. We consider a highly simplified version of the Canham-Helfrich model for phospholipid membranes, in which the bending force and spontaneous curvature are disregarded. The coupled problem is formulated in a fully Eulerian framewor...

In this paper, an interior point algorithm for linear programs is adapted for solving multistage stochastic linear programs. The algorithm is based on Monteiro and Adler’s path-following algorithm for deterministic linear programs. In practice, the complexity of the algorithm is linear with respect to the size of the sample space. The algorithm starts from a feasible solution of the problem and...

We investigate the use of piecewise linear systems, whose coefficient matrix is a piecewise constant function of the solution itself. Such systems arise, for example, from the numerical solution of linear complementarity problems and in the numerical solution of free-surface problems. In particular, we here study their application to the numerical solution of both the (linear) parabolic obstacl...