A Bound on the Number of Integrators Needed to Linearize a Two-input Control System

For nonlinear control systems with two inputs we consider the problem of dynamic feedback linearization. For a restricted class of dynamic compensators that correspond to adding chains of integrators to the inputs, we give an upper bound for the order of the compensator that needs to be considered. Moreover, we show by an example that this bound is sharp

A Test for Differential Flatness by Reduction to Single Input Systems

For nonlinear control systems (p inputs), we present a test for flatness. The method consists of making an initial guess for p-1 of the flat outputs, which may involve parameters still to be determined. A choice of functions of time for the p-1 outputs reduce the system to one with a single input. For single input systems the problem of flatness has been solved and thus leads to the identification of the last flat output, or to obstructions to flatness under the hypotheses. We demonstrate the method for a coupled rigid body in ℝ2 and for a single rigid body in ℝ3

The AISB’08 Symposium on Multimodal Output Generation (MOG 2008)

Welcome to Aberdeen at the Symposium on Multimodal Output Generation (MOG 2008)! In this volume the papers presented at the MOG 2008 international symposium are collected

Evolution of YidC/Oxa1/Alb3 insertases: three independent gene duplications followed by functional specialization in bacteria, mitochondria and chloroplasts

Members of the YidC/Oxa1/Alb3 protein family facilitate the insertion, folding and assembly of proteins of the inner membranes of bacteria and mitochondria and the thylakoid membrane of plastids. All homologs share a conserved hydrophobic core region comprising five transmembrane domains. On the basis of phylogenetic analyses, six subgroups of the family can be distinguished which presumably arose from three independent gene duplications followed by functional specialization. During evolution of bacteria, mitochondria and chloroplasts, subgroup-specific regions were added to the core domain to facilitate the association with ribosomes or other components contributing to the substrate spectrum of YidC/Oxa1/Alb3 proteins

A Homotopy Algorithm for Approximating Geometric Distributions by Integrable Systems

In the geometric theory of nonlinear control systems, the notion of a distribution and the dual notion of codistribution play a central role. Many results in nonlinear control theory require certain distributions to be integrable. Distributions (and codistributions) are not generically integrable and, moreover, the integrability property is not likely to persist under small perturbations of the system. Therefore, it is natural to consider the problem of approximating a given codistribution by an integrable codistribution, and to determine to what extent such an approximation may be used for obtaining approximate solutions to various problems in control theory. In this note, we concentrate on the purely mathematical problem of approximating a given codistribution by an integrable codistribution. We present an algorithm for approximating an m-dimensional nonintegrable codistribution by an integrable one using a homotopy approach. The method yields an approximating codistribution that agrees with the original codistribution on an m-dimensional submanifold E_0 of R^n

Optical investigation into the effects of suffusion in a granular medium

The current paper presents a novel experimental method which is able to capture the effects of suffusion by substitution of the fines in a sample by salt of a similar grain size. The setup is tailored to optically capture the change in soil structure behind a glass window in a plane strain strongbox using a digital camera. Subsequently, digital image correlation techniques have been used to quantify the structural change. The first model test shows promosing insight in the pseudo suffusion mechanism. The test setup therefore offers a valuable addition to permeameter tests.<br/

TIPS for Scaling up Research in Upper Limb Prosthetics

Many research initiatives have been employed in upper limb prosthetics (ULP) in the last few decades. The body of knowledge is growing and inspired by new and interesting technology that has been brought to the market to facilitate functioning of people with upper limb defects. However, a lot of research initiatives do not reach the target population. Several reasons can be identified as to why research does not move beyond the lab, such as lack of research quality, disappointing results of new initiatives, lack of funding to further develop promising initiatives, and poor implementation or dissemination of results. In this paper, we will appraise the current status of the research in ULP. Furthermore, we will try to provide food for thought to scale up research in ULP, focusing on (1) translation of research findings, (2) the quality of innovations in the light of evidence-based medicine and evidence-based practice, (3) patient involvement, and (4) spreading of research findings by focusing on implementation and dissemination of results and collaboration in a national and international perspective. With this paper, we aim to open the discussion on scaling up research in the community of professionals working in the field of ULP

Defying Borders: Transforming Learning Through Collaborative Feminist Organizing and Interdisciplinary, Transnational Pedagogy

The authors provide a case study of how a group of faculty members was able to initiate a transformation in student learning and institutional structures at a small university in the Midwestern U.S. through the introduction of collaborative feminist organizing and pedagogy. It details faculty-led initiatives that set the stage for innovative teaching and learning, and it describes the authors\u27 experience in the face of resistance when introducing a global women\u27s human rights course into the university\u27s new core curriculum. Because of its divers, interdisciplinary and transnational content, this course challenged deeply ingrained disciplinary and pedagogical borders of both traditional area studies and the field of history. The authors argue that progress toward diverse curricula can be made when colleagues work collaboratively and apply innovative pedagogical models to the classroom. Although specific to one university, these challenges to and strategies for transformation have broader application to all faculty seeking to diversify curricula and institutions

To pool or not to pool in hospitals: a theoretical and practical comparison for a radiotherapy outpatient department

This paper examines whether urgent and regular patients waiting for a consultation at a radiotherapy outpatient department should be pooled or not. Both queuing theory and discrete event simulation were applied to a realistic case study. The theoretical approach shows that pooling is not always beneficial with regard to the waiting times of urgent patients. Furthermore, the practical approach indicates that the separation of queues may require less capacity to meet the waiting time performance target for urgent as well as regular patients. The results seem to be of general interest for hospital