Admission Control for TCP Flows Using Packet Classes and Edge-to-edge Measurements of Aggregates

TCP flows from applications such as the web or ftp are well supported by a Guaranteed Minimum Throughput Service (GMTS), which provides a minimum network throughput to the flow and, if possible, an extra throughput. We propose a scheme for a GMTS using Admission Control (AC) that is able to provide different minimum throughput to different users and that is suitable for "standard" TCP flows. Moreover, we consider a multidomain scenario where the scheme is used in one of the domains, and we propose some mechanisms for the interconnection with neighbor domains. The whole scheme uses a small set of packet classes in a core-stateless network where each class has a different discarding priority in queues assigned to it. The AC method involves only edge nodes and uses a special probing packet flow (marked as the highest discarding priority class) that is sent continuously from ingress to egress through a path. The available throughput in the path is obtained at the egress using measurements of flow aggregates, and then it is sent back to the ingress. At the ingress each flow is detected using an implicit way and then it is admission controlled. If it is accepted, it receives the GMTS and its packets are marked as the lowest discarding priority classes; otherwise, it receives a best-effort service. The scheme is evaluated through simulation in a simple "bottleneck" topology using different traffic loads consisting of "standard" TCP flows that carry files of varying sizes

Lightweight monitoring of label switched paths for bandwidth management

The purpose of resource management is the efficient and effective use of network resources, for instance bandwidth. In this article, a connection oriented network scenario is considered, where a certain amount of bandwidth is reserved for each label switch path (LSP), which is a logical path, in a MPLS or GMPLS environment. Assuming there is also some kind of admission control (explicit or implicit), these environments typically provide quality of service (QoS) guarantees. It could happen that some LSPs become busy, thus rejecting connections, while other LSPs may be under-utilised. We propose a distributed lightweight monitoring technique, based on threshold values, the objective of which is to detect congestion when it occurs in an LSP and activate the corresponding alarm which will trigger a dynamic bandwidth reallocation mechanism

La Contribución de los conocimientos de los alumnos a los procesos de aprendizaje

El aprendizaje de la lengua escrita, como cualquier otro aprendizaje, es un resultado conjunto del aprendiz y del entorno. Aunque seria más apropiado hablar de los entornos, en plural, ya que este aprendizaje se nutre de múltiples entornos: la familia, la comunidad cercana, la escuela, el aula. La misma multiplicidad impera en los conocimientos y habilidades del aprendiz. El presente trabajo forma parte de un proyecto que estudia la contribución del aula y de los conocimientos del aprendiz al aprendizaje de la lengua escrita (SEJ2006‐05292) pero aquí nos centraremos en la contribución de aprendiz. Nos hemos propuesto, en primer lugar detectar el conocimiento inicial de los niños en lectura y escritura y en un conjunto de ámbitos considerados clave para su aprendizaje y, en segundo lugar comprobar el desempeño de esos mismos niños al finalizar el primer grado de primaria. Aunque la construcción de conocimientos sobre la lengua escrita es muy precoz, en nuestro medio el último ano de educación infantil y el primero de educación primaria se consideran clave para este aprendizaje. Por lo tanto, evaluamos esos conocimientos al comenzar el ultimo ano de educación infantil (evaluación inicial) y al final de primer curso de primaria (evaluación final). En tercer lugar nos propusimos explicar progresos o retrocesos en el aprendizaje de la lengua escrita. Para ello, comprobamos la incidencia del conocimiento inicial y de las prácticas docentes en los logros de aprendizaje pero también las interacciones y las estrategias que los niños ponen en juego en el aula. Observamos a un grupo reducido de alumnos en actividades de aula caracterizadas por diferentes perfiles de prácticas docentes durante el último ano de educación infantil y el primero de educación primaria

Multivariate Statistical Process Control and Case-Based Reasoning for situation assessment of Sequencing Batch Reactors

ABSRACT This thesis focuses on the monitoring, fault detection and diagnosis of Wastewater Treatment Plants (WWTP), which are important fields of research for a wide range of engineering disciplines. The main objective is to evaluate and apply a novel artificial intelligent methodology based on situation assessment for monitoring and diagnosis of Sequencing Batch Reactor (SBR) operation. To this end, Multivariate Statistical Process Control (MSPC) in combination with Case-Based Reasoning (CBR) methodology was developed, which was evaluated on three different SBR (pilot and lab-scales) plants and validated on BSM1 plant layout.