Distributed PC Based Routers: Bottleneck Analysis and Architecture Proposal

Recent research in the different functional areas of modern routers have made proposals that can greatly increase the efficiency of these machines. Most of these proposals can be implemented quickly and often efficiently in software. We wish to use personal computers as forwarders in a network to utilize the advances made by researchers. We therefore examine the ability of a personal computer to act as a router. We analyze the performance of a single general purpose computer and show that I/O is the primary bottleneck. We then study the performance of distributed router composed of multiple general purpose computers. We study the performance of a star topology and through experimental results we show that although its performance is good, it lacks flexibility in its design. We compare it with a multistage architecture. We conclude with a proposal for an architecture that provides us with a forwarder that is both flexible and scalable.© IEE

Estrategias de redes de apoyo en el proceso de inserción laboral por parte de mujeres en condición sola con hijos(as) menores de 12 años de edad, pertenecientes a la escuela Enrique Cárdenas, Reñaca Alto, Viña del Mar

Tesis (Trabajo Social)Este proyecto de investigación trata sobre las redes de apoyo que articulan las madres en condición sola con hijos dependientes menores de 12 años, para permitir su inserción laboral. Específicamente se analiza la forma cómo se estructuran las redes de acuerdo a sus diferentes categorías como las redes familiares, de amistades y gubernamentales principalmente. Se encontró que en Chile estas mujeres reciben importantes ayudas para cumplir con sus diferentes roles como madres jefas de hogar de parte de los programas de gobierno, lo que se complementa con la gestión que cada una desarrolla de modo personal, lo que resulta muy importante para garantizar el bienestar y la calidad de vida de su familia. Al respecto se ha observado que estas madres en situación sola si reciben colaboración de las diferentes redes, lo cual implica que ellas deben saber tomar decisiones para elegir lo más conveniente, dada su condición particular de vulnerabilidad al carecer de la compañía del padre de sus hijos y de recursos económicos suficientes. Por este motivo deben orientar, sostener y articular sus redes de apoyo familiar, comunitario e institucional facilitando su participación en el mercado laboral. Actualmente en Chile existe un aumento en la inserción laboral femenina general, sin embargo también se presenta una fuerte exclusión del mercado laboral de los segmentos menos calificados, por lo cual se ven obligadas a desarrollar diferentes actividades en el mercado informal, en este contexto cada red cumple con una función específica para contribuir al desarrollo de este tipo de familia

Modifications to the Machine Optics of BESSY II Necessitated by the EMIL Project

The Helmholtz Zentrum Berlin and the Max Planck Society are going to build a new dedicated X ray beam line at the synchrotron light source BESSY II which will be used for analyzing materials for renewable energy generation. The new large scale project has been dubbed EMIL. In this document we present the modifications to the machine optics and to what extent these changes affect the performance of BESSY I

D-brane charges on non-simply connected groups

The maximally symmetric D-branes of string theory on the non-simply connected Lie group SU(n)/Z_d are analysed using conformal field theory methods, and their charges are determined. Unlike the well understood case for simply connected groups, the charge equations do not determine the charges uniquely, and the charge group associated to these D-branes is therefore in general not cyclic. The precise structure of the charge group depends on some number theoretic properties of n, d, and the level of the underlying affine algebra k. The examples of SO(3)=SU(2)/Z_2 and SU(3)/Z_3 are worked out in detail, and the charge groups for SU(n)/Z_d at most levels k are determined explicitly.Comment: 31 pages, 1 figure. 2 refs added. Added the observation: the charge group for each su(2) theory equals the centre of corresponding A-D-E grou

D-branes in T-fold conformal field theory

We investigate boundary dynamics of orbifold conformal field theory involving T-duality twists. Such models typically appear in contexts of non-geometric string compactifications that are called monodrofolds or T-folds in recent literature. We use the framework of boundary conformal field theory to analyse the models from a microscopic world-sheet perspective. In these backgrounds there are two kinds of D-branes that are analogous to bulk and fractional branes in standard orbifold models. The bulk D-branes in T-folds allow intuitive geometrical interpretations and are consistent with the classical analysis based on the doubled torus formalism. The fractional branes, on the other hand, are `non-geometric' at any point in the moduli space and their geometric counterparts seem to be missing in the doubled torus analysis. We compute cylinder amplitudes between the bulk and fractional branes, and find that the lightest modes of the open string spectra show intriguing non-linear dependence on the moduli (location of the brane or value of the Wilson line), suggesting that the physics of T-folds, when D-branes are involved, could deviate from geometric backgrounds even at low energies. We also extend our analysis to the models with SU(2) WZW fibre at arbitrary levels.Comment: 38 pages, no figure, ams packages. Essentially the published versio

Twisted brane charges for non-simply connected groups

The charges of the twisted branes for strings on the group manifold SU(n)/Z_d are determined. To this end we derive explicit (and remarkably simple) formulae for the relevant NIM-rep coefficients. The charge groups of the twisted and untwisted branes are compared and found to agree for the cases we consider.Comment: 30 page

The charges of a twisted brane

The charges of the twisted D-branes of certain WZW models are determined. The twisted D-branes are labelled by twisted representations of the affine algebra, and their charge is simply the ground state multiplicity of the twisted representation. It is shown that the resulting charge group is isomorphic to the charge group of the untwisted branes, as had been anticipated from a K-theory calculation. Our arguments rely on a number of non-trivial Lie theoretic identities.Comment: 27 pages, 1 figure, harvmac (b