Heuristic for the design of fault tolerant logical topology.

Wavelength division multiplexing (WDM) in optical fiber networks is widely viewed as the savior for its potential to satisfy the huge bandwidth requirement of network users. Optical cross connect (OCX) in WDM network facilitates the switching of signal on any wavelength from any input port to any output port. As a result, it is possible to establish ligthpaths between any pair of nodes. The set of lightpaths established over fiber links defines logical topology. In our thesis, we proposed a heuristic approach for the design of fault tolerant logical topology. Our design approach generalizes the design protection concept and enforces wavelength continuity constraint in a multi-hop optical network. In our work, we first designed logical topology for fault free state of the network. We, then, added additional lightpaths for each single link failure scenario. Numerical results clearly show that our approach outperforms Shared path protection and Dedicated path protection. Our simulation result shows that our approach is feasible for large networks. (Abstract shortened by UMI.) Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .S24. Source: Masters Abstracts International, Volume: 44-03, page: 1413. Thesis (M.Sc.)--University of Windsor (Canada), 2005

IEEE Access Special Section Editorial: Big Data Technology and Applications in Intelligent Transportation

During the last few years, information technology and transportation industries, along with automotive manufacturers and academia, are focusing on leveraging intelligent transportation systems (ITS) to improve services related to driver experience, connected cars, Internet data plans for vehicles, traffic infrastructure, urban transportation systems, traffic collaborative management, road traffic accidents analysis, road traffic flow prediction, public transportation service plan, personal travel route plans, and the development of an effective ecosystem for vehicles, drivers, traffic controllers, city planners, and transportation applications. Moreover, the emerging technologies of the Internet of Things (IoT) and cloud computing have provided unprecedented opportunities for the development and realization of innovative intelligent transportation systems where sensors and mobile devices can gather information and cloud computing, allowing knowledge discovery, information sharing, and supported decision making. However, the development of such data-driven ITS requires the integration, processing, and analysis of plentiful information obtained from millions of vehicles, traffic infrastructures, smartphones, and other collaborative systems like weather stations and road safety and early warning systems. The huge amount of data generated by ITS devices is only of value if utilized in data analytics for decision-making such as accident prevention and detection, controlling road risks, reducing traffic carbon emissions, and other applications which bring big data analytics into the picture

Optimización metaheurística para la planificación de redes WDM

Las implementaciones actuales de las redes de telecomunicaciones no permiten soportar el incremento en la demanda de ancho de banda producido por el crecimiento del tráfico de datos en las últimas décadas. La aparición de la fibra óptica y el desarrollo de la tecnología de multiplexación por división de longitudes de onda (WDM) permite incrementar la capacidad de redes de telecomunicaciones existentes mientras se minimizan costes. En este trabajo se planifican redes ópticas WDM mediante la resolución de los problemas de Provisión y Conducción en redes WDM (Provisioning and Routing Problem) y de Supervivencia (Survivability Problem). El Problema de Conducción y Provisión consiste en incrementar a mínimo coste la capacidad de una red existente de tal forma que se satisfaga un conjunto de requerimientos de demanda. El problema de supervivencia consiste en garantizar el flujo del tráfico a través de una red en caso de fallo de alguno de los elementos de la misma. Además se resuelve el Problema de Provisión y Conducción en redes WDM con incertidumbre en las demandas. Para estos problemas se proponen modelos de programación lineal entera. Las metaheurísticas proporcionan un medio para resolver problemas de optimización complejos, como los que surgen al planificar redes de telecomunicaciones, obteniendo soluciones de alta calidad en un tiempo computacional razonable. Las metaheurísticas son estrategias que guían y modifican otras heurísticas para obtener soluciones más allá de las generadas usualmente en la búsqueda de optimalidad local. No garantizan que la mejor solución encontrada, cuando se satisfacen los criterios de parada, sea una solución óptima global del problema. Sin embargo, la experimentación de implementaciones metaheurísticas muestra que las estrategias de búsqueda embebidas en tales procedimientos son capaces de encontrar soluciones de alta calidad a problemas difíciles en industria, negocios y ciencia. Para la solución del problema de Provisión y Conducción en Redes WDM, se desarrolla un algoritmo metaheurístico híbrido que combina principalmente ideas de las metaheurísticas Búsqueda Dispersa (Scatter Search) y Búsqueda Mutiarranque (Multistart). Además añade una componente tabú en uno de los procedimiento del algoritmo. Se utiliza el modelo de programación lineal entera propuesto por otros autores y se propone un modelo de programación lineal entera alternativo que proporciona cotas superiores al problema, pero incluye un menor número de variables y restricciones, pudiendo ser resuelto de forma óptima para tamaños de red mayores. Los resultados obtenidos por el algoritmo metaheurístico diseñado se comparan con los obtenidos por un procedimiento basado en permutaciones de las demandas propuesto anteriormente por otros autores, y con los dos modelos de programación lineal entera usados. Se propone modelos de programación lineal entera para sobrevivir la red en caso de fallos en un único enlace. Se proponen modelos para los esquemas de protección de enlace compartido, de camino compartido con enlaces disjuntos, y de camino compartido sin enlaces disjuntos. Se propone un método de resolución metaheurístico que obtiene mejores costes globales que al resolver el problema en dos fases, es decir, al resolver el problema de servicio y a continuación el de supervivencia. Se proponen además modelos de programación entera para resolver el problema de provisión en redes WDM con incertidumbres en las demandas

Multi-Overlay network planning by applying a variable neighbourhood search approach.

This thesis presents an approach for the topological design and sizing of an IP/MPLSmultioverlay network with the purpose of minimising the economical resources involved on ANTEL (Administración Nacional de Telecomunicaciones) infrastructure. The overlay network is an MPLS Data Network, which physically exchange traffic over an existent Transport infrastructure. The solution to find must be of optimal cost, robust to simple failures in the Transport Network, and deal with differential traffic. The mathematical model for this kind of problems is obtained by using weighted graphs which leads to a combinatorial optimisation formulation. As the problem undertaken is NP-Hard concerning computational complexity, a metaheuristic methodology is employed, which reaches approximate though often optimal solutions in a reasonable time. The metaheuristic selected is VNS (Variable Neihbourhood Search), which has shown positive qualities as simplicity, efficiency and effectiveness among others. Then, the implemented local searches and achieved results are described

Agile AI development for Real World Solutions

This keynote will analyse the importance of IoT, Blockchain and Edge Computing as contributors to the development of distributed intelligent systems that have the capacity to interact with the environment "Smart" infrastructures need to incorporate all added-value resources so they can offer useful services to the society, while reducing costs, ensuring reliability and improving the quality of life of the citizens. The combination of AI, IoT and Blockchain in an Edge Computing model or elsewhere, offers a world of possibilities and opportunities

Design and protection algorithms for path level aggregation of traffic in WDM metro optical networks

Wavelength Division Multiplexing (WDM) promises to offer a cost effective and scalable solution to meet the emerging demands of the Internet. WDM splits the tremendous bandwidth latent in a fiber into multiple non-overlapping wavelength channels, each of which can be operated at the peak electronic rate. Commercial systems with 128 wavelengths and transmission rates of up to 40 Gbps per wavelength have been made possible using state of the art optical technologies to deal with physical impairments. Systems with higher capacities are likely to evolve in the future. The end user requirements for bandwidth, on the other hand, have been ranging from 155 Mbps to 2.5 Gbps. Dedicating a wavelength for each end user will lead to severe underutilization of WDM channels. This brings to forefront the requirement for sharing of bandwidth in a wavelength among multiple end users.;The concept of wavelength sharing among multiple clients is called grooming. Grooming can be done purely at the optical layer (optical grooming) or it can be done with support from the client layer (electronic grooming). The advantage of all optical grooming is the ease of scalability due to its transparency as opposed to electronic grooming which is constrained by electronic bottlenecks. Efforts towards enhancing optical grooming is pursued through increasing optical switching speeds. However, technologies to make optical switches with high speeds, large port counts and low insertion losses have been elusive and may continue to remain so in the near future.;Recently, there have been some research into designing new architectures and protocols focused on optical grooming without resorting to fast optical switching. Typically, this is achieved in three steps: (1) configure the circuit in the form of a path or a tree; (2) use optical devices like couplers or splitters to allow multiple transmitters and/or receivers to share the same circuit; and (3) provide an arbitration mechanism to avoid contention among end users of the circuit. This transparent sharing of the wavelength channel utilizes the network resources better than the conventional low-speed circuit switched approaches. Consequently, it becomes important to quantify the improvement in achieved performance and evaluate if the reaped benefits justify the cost of the required additional hardware and software.;The contribution of this thesis is two fold: (1) developing a new architecture called light-trails as an IP based solution for next generation WDM optical networks, and (2) designing a unified framework to model Path Level Aggregation of Traffic in metrO Optical Networks (PLATOONs). The algorithms suggested here have three features: (1) accounts for four different path level aggregation strategies---namely, point to point (for example, lightpaths), point to multi-point (for example, source based light-trails), multi-point to point (for example, destination based light-trails) and multi-point to multi-point (for example, light-trails); (2) incorporates heterogenous switching architectures; and (3) accommodates multi-rate traffic. Algorithms for network design and survivability are developed for PLATOONs in the presence of both static and dynamic traffic. Connection level dedicated/shared, segregated/mixed protection schemes are formulated for single link failures in the presence of static and dynamic traffic. A simple medium access control protocol that avoids collisions when the channel is shared by multiple clients is also proposed.;Based on extensive simulations, we conclude that, for the studied scenarios, (1) when client layer has no electronic grooming capabilities, light-trails (employing multi-point to multi-point aggregation strategy) perform several orders of magnitude better than lightpaths and (2) when client layer has full electronic grooming capabilities, source based light-trails (employing point to multi-point aggregation strategy) perform the best in wavelength limited scenarios and lightpaths perform the best in transceiver limited scenarios.;The algorithms that are developed here will be helpful in designing optical networks that deploy path level aggregation strategies. The proposed ideas will impact the design of transparent, high-speed all-optical networks.</p

A Centralized Clustering approach for Wireless Sensor Networks

Wireless Sensor Networks consists of hundreds and thousands of micro sensor nodes that monitor a remote environment by data aggregation from individual nodes and transmitting this data to the base station for further processing and inference. The energy of the battery operated nodes is the most vulnerable resource of the WSN, which is depleted at a high rate when information is transmitted, because transmission energy is dependent on the distance of transmission. In a clustering approach, the Cluster Head node looses a significant amount of energy during transmission to base station. So the selection of Cluster Head is very critical. An effective selection protocol should choose Cluster Heads based on the geographical location of node and its remaining energy. In this work a centralized protocol for Cluster Head selection in WSN is discussed, which is run at the base station, thus reducing the nodes' energy consumption and increasing their life-time. The primary idea is implemented using a fuzzy-logic based selection of Cluster Head from among the nodes of network, which is concluded depending on two parameters, the current energy of the node and the distance of the node from the base station. The protocol is named LEACH-C(ED)-Centralized LEACH based on Energy and Distance, and is run periodically at the base station where a new set of cluster heads are selected at every round, thus distributing the energy load in the network and increasing the network lifetime. The simulation results show that the proposed approach is more effective than the existing LEACH-Centralized protocol