Search

En el Colegio Nacional trabajamos con la seguridad de que el seguimiento y evaluación es parte central del proceso de enseñanza, no es una etapa final. Para los/as estudiantes es una toma de conciencia de los aprendizajes adquiridos, para los docentes es fuente de conocimiento que permite generar conclusiones de mejora del proceso en forma constante. Es una práctica sistemática, planificada e integrada a la enseñanza que tiene como finalidad apreciar, conocer y comprender diferentes aspectos de la realidad educativa. Dada la importancia de la evaluación como componente esencial de la enseñanza, en el Colegio diseñamos un modelo de seguimiento del proceso de estudiantes y docentes en esta “educación remota de emergencia” para poder expresar, integrar y volcar dicha información, Documento generado por la virtualizaciòn del Colegio por la pandemia del COVID 19., Colegio Nacional "Rafael Hernández"

The main objective of this thesis is to find good quality solutions for rep- resentative instances of the problem of designing a resilient and low cost IP/MPLS network, to be deployed over an existing optical transport network. This research is motivated by two complementary real-world application cases, which comprise the most important commercial and academic networks of Uruguay.To achieve this goal, we performed an exhaustive analysis of existing models and technologies. From all of them we took elements that were contrasted with the par- ticular requirements of our counterparts. We highlight among these requirements, the need of getting solutions transparently implementable over a heterogeneous net- work environment, which limit us to use widely standardized features of related technologies. We decided to create new models more suitable to fit these needs.These models are intrinsically hard to solve (NP-Hard). Thus we developed meta- heuristics to find solutions to these real-world instances. Evolutionary Algorithms and Greedy Randomized Adaptive Search Procedures obtained the best results.As it usually happens, prospective real-world problems are surrounded by uncer- tainty. Therefore, we have worked closely with our counterparts to reduce the fuzzi- ness upon data to a set of representative cases. They were combined with different strategies of design to get to scenarios, which were translated into representative instances of these problems.Finally, the algorithms were fed with this information, and from their outcome we derived our results and conclusions.; L'objectif principal de cette thèse est de trouver des solutions de bonne qualité à des instances représentatives du problème de la conception d'un réseau IP/MPLS qui soit résistant et de faible coût, déployé sur une infrastructure de transport optique existante. Ces travaux ont été motivés par deux cas réels, concernant les plus grands réseaux commercial et académique d'Uruguay. Ce type de problème étant NP difficile, nous avons développé des méta-heuristiques pour trouver des solutions, basées dans les méthodologies GRASP et GA, combinées avec une analyse détaillée des incertitudes associées avec les problèmes. Ces travaux ont ainsi permis de traiter efficacement les deux familles de problèmes réels de grande taille.

Optimal Design of a Multi-Layer Network an IP/MPLS Over DWDM Application Case

An Autonomous System (AS) is a group of Internet Protocol-based networks with a single and clearly defined external routing policy, usually under single ownership, trust or administrative control. The AS represents a connected group of one or more blocks of IP addresses, called IP prefixes, that have been assigned to that organization and provides a single routing policy to systems outside the AS. The Internet is composed of the interconnection of several thousands of ASes, which use the Border Gateway Protocol (BGP) to exchange network prefixes (aggregations of IP addresses) reachability advertisements. BGP advertisements (or updates) are sent over BGP sessions administratively set between pairs of routers. BGP is a path vector routing protocol and is used to span different ASes. A path vector protocol defines a route as a pairing between a destination and the attributes of the path to that destination. Interior Border Gateway Protocol (iBGP) refers to the BGP neighbor relationship within the same AS. When BGP neighbor relationship are formed between two peers belonging to different AS are called Exterior Border Gateway Protocol (eBGP). In the last case, BGP routers are called Autonomous System Border Routers (ASBRs), while those running only iBGP sessions are referred to as Internal Routers (IRs). Traditional iBGP implementations require a full-mesh of sessions among routers of each AS.

The Steiner Tree Problem is an umbrella of combinatorial optimization problems in graphs, most of them NP-Hard, within which, the Steiner Tree Problem in graphs (STP) is perhaps one of the most famous and widely studied. The STP consists in optimally interconnect a given set of terminal or mandatory nodes within a graph with edges of positive weights, eventually using other optional nodes. It has a wide range of applications from circuit layouts to network design, so plenty of models to find its exact solutions have been crafted. Traditionally, due to its intrinsic complexity, heuristic approaches have been used to find good quality solutions to the STP. Currently, the outstanding computing power resulting from combining developments in hardware and software capabilities makes it possible to rely upon exact formulations and generic algorithms to solve complex instances of the problem. This work introduces a flow-based mixed-integer problem formulation (MIP) for the STP using the SteinLib, a reference test-set repository. Later on, that MIP formulation is modified to solve the Quality of Service Multicast Tree problem (QoSTP). To the best of our knowledge, there is no previous MIP formulation. While existing approaches go all the way of approximation algorithms to find solutions, this MIP formulation shows promising experimental results. Optimal solutions are found for several instances, while low feasible-to-optimal gaps were obtained for most of the remaining ones.

Las redes de telecomunicaciones han crecido en forma acelerada en los últimos años impulsadas fundamentalmente por la enorme oferta de contenido sobre Internet. Las tecnologías de red han evolucionado acompañando esta demanda y los operadores han sabido aceptar el desafío de este crecimiento brindando cada vez más y mejores servicios a sus clientes. Con ciclos de renovación de infraestructura muchísimos mas cortos que los históricos y con precios de los servicios a la baja por la fuerte competencia, los operadores de red enfrentan desafíos enormes para mantenerse en el mercado. Estos desafíos incluyen: la diferenciación de los servicios basados en precio y calidad, la generación de ingresos incursionando en nuevos negocios y la optimización de los costos operativos y de despliegue de infraestructura. El objetivo de esta tesis es la búsqueda de soluciones de buena calidad para el diseño de redes de telecomunicaciones multi-capa sobre redes ópticas existentes, optimizando el costo de su despliegue y asegurando un buen nivel de resiliencia ante fallas de la infraestructura física subyacente. Este trabajo continúa investigaciones previas sobre redes sintéticas y reales. Basándose en la experiencia y los resultados obtenidos explora nuevos algoritmos basados en heurísticas y métodos exactos para el diseño de este tipo de redes. Esta Tesis cuenta con el soporte del proveedor de comunicaciones uruguayo Antel, el cual gestiona la más importante red de telecomunicaciones de Uruguay y se encuentra además en pleno proceso de expansión internacional de su infraestructura de red y servicios. Los resultados obtenidos logran mejorar soluciones previas sobre redes reales de este operador y generan soluciones de muy buena calidad sobre instancias para los cuales no se conocen resultados previos.