Preconditioning and iterative solution of symmetric indefinite linear systems arising from interior point methods for linear programming

We study the preconditioning of symmetric indefinite linear systems of equations that arise in interior point solution of linear optimization problems. The preconditioning method that we study exploits the block structure of the augmented matrix to design a similar block structure preconditioner to improve the spectral properties of the resulting preconditioned matrix so as to improve the convergence rate of the iterative solution of the system. We also propose a two-phase algorithm that takes advantage of the spectral properties of the transformed matrix to solve for the Newton directions in the interior-point method. Numerical experiments have been performed on some LP test problems in the NETLIB suite to demonstrate the potential of the preconditioning method discussed.

Behavioral Measures and their Correlation with IPM Iteration Counts on Semi-Definite Programming Problems

We study four measures of problem instance behavior that might account for the observed differences in interior-point method (IPM) iterations when these methods are used to solve semidefinite programming (SDP) problem instances: (i) an aggregate geometry measure related to the primal and dual feasible regions (aspect ratios) and norms of the optimal solutions, (ii) the (Renegar-) condition measure C(d) of the data instance, (iii) a measure of the near-absence of strict complementarity of the optimal solution, and (iv) the level of degeneracy of the optimal solution. We compute these measures for the SDPLIB suite problem instances and measure the correlation between these measures and IPM iteration counts (solved using the software SDPT3) when the measures have finite values. Our conclusions are roughly as follows: the aggregate geometry measure is highly correlated with IPM iterations (CORR = 0.896), and is a very good predictor of IPM iterations, particularly for problem instances with solutions of small norm and aspect ratio. The condition measure C(d) is also correlated with IPM iterations, but less so than the aggregate geometry measure (CORR = 0.630). The near-absence of strict complementarity is weakly correlated with IPM iterations (CORR = 0.423). The level of degeneracy of the optimal solution is essentially uncorrelated with IPM iterations.

Programa d'habilitats socials pels alumnes de l’Aula Oberta del Primer Cicle d’ESO: IES Vallvera

Treball que recull l'experiència de l’autora durant 4 mesos en l’IES Vallvera. Durant aquest temps ha pogut observar, aprendre i conèixer les tasques dels professionals de la psicopedagogia. L’IES Vallvera és un centre que acull molts alumnes immigrants, i per tant el tracte amb alumnes i l’assessorament d’aquests és el treball del dia a dia de la psicopedagoga del centre

The improvement of reading skills of L1 and ESL children using a Response to Intervention (RtI) Model

Resumen tomado de la publicaci??n

Tutor's guide to Study Skills Toolkit 2007

Tutor's guide for using the Study Skill's Toolkit learning objects - these are currently available to all 1st year undergraduates in the University via Blackboard. Produced by Julie Watson in elanguages.

Postgraduate Demonstration Skills

A PowerPoint presentation used to support a skills development session for postgraduate students who wish to act as demonstrators in lab and workshop sessions.

Introduction to JavaScript Programming

These are the resources for an introductory lecture in JavaScript programming. Exercises are provided to practice simple JavaScript programming, including a template for a DHTML implementation of Conway's Game of Life (with encrypted solution).

Study Skills Toolkit: Reference list for tutors

A complete reference list for tutors of all learning resources in the Study Skills Toolkit (as of Oct. 2008) available through Blackboard VLE

Oral Presentation Skills

This PowerPoint is used to support a workshop for University staff and students who are preparing a conference presentation. It highlights the major issues that they will need to consider when planning, practising and delivering their talk.

Mathematical Programming

Exam questions and solutions for a third year mathematical programming course.

PowerPoint - basic skills training

This step-by-step guided worksheet and accompanying PowerPoint file introduce some key skills: - reorganising slides and bullets - creating speaker notes - printing slide handouts - including hyperlinks - adding images Simple stuff, but many find it useful - it uses Office 2004 (XP)

Research and Communication Skills

A Collection of Material for Research and Communication Skills

Study Skills: Precis and Argumentation

Society is catching up with the implications of the Web; its use is not straightforward and well-understood. Web Scientists will need to be able to handle arguments about equivocal perspectives on the Web's impact.

Sound Recording Skills presentation by Matt Grover

Covers defining a sound in terms of amplitude, frequency, time, timbre and space. How sound behaves within a space. Digital recording settings. Winchester School of Art loan equipment. Winchester School of Art editing software overview.