Towards device-size atomistic models of amorphous silicon

The atomic structure of amorphous materials is believed to be well described by the continuous random network model. We present an algorithm for the generation of large, high-quality continuous random networks. The algorithm is a variation of the "sillium" approach introduced by Wooten, Winer, and Weaire. By employing local relaxation techniques, local atomic rearrangements can be tried that scale almost independently of system size. This scaling property of the algorithm paves the way for the generation of realistic device-size atomic networks.Comment: 7 pages, 3 figure

Local convergence of the Levenberg-Marquardt method under H\"{o}lder metric subregularity

We describe and analyse Levenberg-Marquardt methods for solving systems of nonlinear equations. More specifically, we propose an adaptive formula for the Levenberg-Marquardt parameter and analyse the local convergence of the method under H\"{o}lder metric subregularity of the function defining the equation and H\"older continuity of its gradient mapping. Further, we analyse the local convergence of the method under the additional assumption that the \L{}ojasiewicz gradient inequality holds. We finally report encouraging numerical results confirming the theoretical findings for the problem of computing moiety conserved steady states in biochemical reaction networks. This problem can be cast as finding a solution of a system of nonlinear equations, where the associated mapping satisfies the \L{}ojasiewicz gradient inequality assumption.Comment: 30 pages, 10 figure

Traffic engineering eye diagram

It is said that a picture is worth a thousand words - this statement also applies to networking topics. Thus, to effectively monitor network performance we need tools which present the performance metrics in a graphical way which is also clear and informative. We propose a tool for this purpose which we call the traffic engineering eye diagram (TEED). Eye diagrams are used in digital communications to analyse the quality of a digital signal; the TEED can similarly he used in the traffic engineering field to analyse the load balancing ability of a TE algorithm. In this paper we describe how to create such TEEDs and how to use them to analyse and compare various traffic engineering approaches

Scheduling Sensors for Guaranteed Sparse Coverage

Sensor networks are particularly applicable to the tracking of objects in motion. For such applications, it may not necessary that the whole region be covered by sensors as long as the uncovered region is not too large. This notion has been formalized by Balasubramanian et.al. as the problem of $\kappa$-weak coverage. This model of coverage provides guarantees about the regions in which the objects may move undetected. In this paper, we analyse the theoretical aspects of the problem and provide guarantees about the lifetime achievable. We introduce a number of practical algorithms and analyse their significance. The main contribution is a novel linear programming based algorithm which provides near-optimal lifetime. Through extensive experimentation, we analyse the performance of these algorithms based on several parameters defined

Analyse komplexer Knochenbewegungen in Folgen von MRT Aufnahmen

Schädigungen des Bewegungsapparates können häufig nicht durch Auswertung von Einzelaufnahmen sondern nur durch Analyse der Bewegungsabläufe von Knochen diagnostiziert werden. Dies gilt beispielsweise für Schädigungen der Bänder bzw. Knorpel im Bereich des Kniegelenks, der Hals- und der Lendenwirbelsäule. In diesem Beitrag wird ein System zur Diagnose von Schädigungen des Bänderapparates der Handwurzelknochen vorgestellt (karpale Instabilitäten). Das Verfahren unterstützt insbesondere die Diagnose der nach Stürzen am häufigsten auftretenden 'Scapholunären Dissoziation', die bei einem Bänderriß zwischen dem Scaphoideum (Kahnbein) und dem Lunatum (Mondbein) sichtbar wird. Im Gegensatz beispielsweise zur Wirbelsäule führen die Handwurzelknochen Bewegungen um alle drei Raumachsen aus. Eine geeignete Schichtauswahl ermöglicht dennoch eine erfolgreiche Bewegungsvermessung mittels 2-D Analyse

Disciplined: Using educational studies to analyse 'Humanities Computing'

Humanities Computing is an emergent field. The activities described as 'Humanities Computing' continue to expand in number and sophistication, yet no concrete definition of the field exists, and there are few academic departments that specialize in this area. Most introspection regarding the role, meaning, and focus of "Humanities Computing" has come from a practical and pragmatic perspective from scholars and educators within the field itself. This article provides an alternative, externalized, viewpoint of the focus of Humanities Computing, by analysing the discipline through its community, research, curriculum, teaching programmes, and the message they deliver, either consciously or unconsciously, about the scope of the discipline. It engages with Educational Theory to provide a means to analyse, measure, and define the field, and focuses specifically on the ACH/ALLC 2005 Conference to identify and analyse those who are involved with the humanities computing community. © 2006 Oxford University Press