Optimization of Free Space Optical Wireless Network for Cellular Backhauling

With densification of nodes in cellular networks, free space optic (FSO) connections are becoming an appealing low cost and high rate alternative to copper and fiber as the backhaul solution for wireless communication systems. To ensure a reliable cellular backhaul, provisions for redundant, disjoint paths between the nodes must be made in the design phase. This paper aims at finding a cost-effective solution to upgrade the cellular backhaul with pre-deployed optical fibers using FSO links and mirror components. Since the quality of the FSO links depends on several factors, such as transmission distance, power, and weather conditions, we adopt an elaborate formulation to calculate link reliability. We present a novel integer linear programming model to approach optimal FSO backhaul design, guaranteeing $K$-disjoint paths connecting each node pair. Next, we derive a column generation method to a path-oriented mathematical formulation. Applying the method in a sequential manner enables high computational scalability. We use realistic scenarios to demonstrate our approaches efficiently provide optimal or near-optimal solutions, and thereby allow for accurately dealing with the trade-off between cost and reliability

Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version

Multiperiod modelling planning and productivity and energy efficient assessment of an industrial gases facility

El creixement de la demanda energètica i el continu desenvolupament tecnològic de la societat estan sobrepassant els límits mediambientals del nostre planeta. Sense les mesures adequades, aquesta situació podria derivar en importants problemes mediambientals que causarien danys irreversibles al medi ambient i al benestar de la humanitat. El sector industrial és el principal consumidor energètic, amb una demanda al voltant d’un terç de la global, un aspecte que té un evident efecte negatiu amb l’impacte mediambiental. Per tant, el repte de mitigar el canvi climàtic implicarà millores en l’ús de la energia a la industria, generant grans oportunitats d’estalvi energètic i reduint el seu impacte mediambiental. En aquest sentit, es essencial obtenir informació derivada de la investigació i l’anàlisi científic que permeti desenvolupar solucions focalitzades en la reducció de costos energètics. Aquesta tesis ha tractat les necessitats particulars de la producció de gasos industrials, creant eines basades en l’optimització matemàtica que permeten una presa de decisions operatives més àgil i efectiva i detectant àrees per la millora energètica. Aquestes eines fomenten i avancen cap a una industria més eficient que permeti un futur més sostenible. Aquesta tesis té dos contribucions principals. D’una banda, s’ha desenvolupat una eina d’optimització multiperiod que permet obtenir la configuració d’operació òptima (des del punt de vista econòmic i energètic) d’un procés de producció de gasos industrials, tenint en compte totes les seves variables. Per altra banda, s’utilitza la metodologia de Data Envelopment Analisis per a comparar diferents unitats de producció de gasos industrials, identificant els focus d’ineficiència i fent recomanacions per a resoldre’ls.El crecimiento de la demanda energética y el continuo desarrollo tecnológico de la sociedad están sobrepasando los límites medioambientales de nuestro planeta. Sin las medidas adecuadas, esta situación puede derivar en importantes problemas medioambientales que podrían causar daños irreversibles al medioambiente y al bienestar de la humanidad. El sector industrial es el principal consumidor energético, consumiendo alrededor de un tercio de la demanda energética global, lo que tiene una evidente relación negativa con el impacto ambiental. Por lo tanto, el reto de mitigar el cambio climático implicará mejoras del uso de la energía en la industria, creando grandes oportunidades de ahorro energético y reduciendo su impacto ambiental. Para ello, es esencial obtener información derivada de la investigación y el análisis científico que permita desarrollar soluciones enfocadas a la reducción de costes energéticos. Esta tesis ha tratado las necesidades particulares de la producción de gases industriales, creando herramientas basadas en la optimización matemática que permiten una toma de decisiones operativas más ágil y efectiva y detectando áreas para la mejora energética. Estas herramientas fomentan y avanzan hacia una industria más eficiente que permita un futuro más sostenible. Esta tesis tiene dos contribuciones principales. Por un lado, se crea una herramienta de optimización multiperiodo que permite obtener la configuración de operación óptima (desde el punto de vista económico y energético) de un proceso de producción de gases industriales, teniendo en cuenta todas sus variables. Por otro lado, se usa la metodología de Data Envelopment Analysis para comparar diferentes unidades de producción de gases industriales, identificando los focos de ineficiencia y haciendo recomendaciones para resolverlos. En definitiva, esta tesis ofrece un conjunto de herramientas prácticas y efectivas que apoyan el proceso de toma de decisiones en actividades industriales y permiten la identificación de oportunidades de mejora energética.The growth of energy demand and the continuous technological development of society are surpassing the environmental limits of our planet. Without adequate measures, this situation can lead to serious environmental problems that could cause irreversible damage to the environment and the well-being of humanity. The industrial sector is the largest energy consumer, with about one-third of global energy demand, which has an evident negative relationship with environmental impact. Therefore, the challenge of mitigating climate change will imply improvements in the energy use in industry, creating great opportunities for energy savings and reducing its environmental impact. In this sense, it is essential to obtain information derived from research and scientific analysis that allows developing solutions focused on the reduction of energy costs. This thesis has dealt with the particular needs of the production of industrial gases, by creating tools based on mathematical optimization models that allow much more agile and effective operational decision-making as well as the detection of areas for energy improvement. These tools encourage and move towards a more efficient industry that allow a more sustainable future. Two main contributions are derived from this thesis. On the one hand, it creates a multiperiod optimization tool that allows obtaining the optimal operational configuration (from the economic and energetic points of view) of an industrial gas manufacturing process, taking into account all the variables that affect the system. On the other hand, the Data Envelopment Analysis methodology is used to compare different industrial gas production units, identifying inefficiency sources and making recommendations to adopt the best practices to solve them. Summarizing, this thesis offers a set of practical and effective tools that support the decision making process in industrial activities and allows the identification of opportunities for energy improvement

Multibody dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: Formulations and Numerical Methods, Efficient Methods and Real-Time Applications, Flexible Multibody Dynamics, Contact Dynamics and Constraints, Multiphysics and Coupled Problems, Control and Optimization, Software Development and Computer Technology, Aerospace and Maritime Applications, Biomechanics, Railroad Vehicle Dynamics, Road Vehicle Dynamics, Robotics, Benchmark Problems. The conference is organized by the Department of Mechanical Engineering of the Universitat Politècnica de Catalunya (UPC) in Barcelona. The organizers would like to thank the authors for submitting their contributions, the keynote lecturers for accepting the invitation and for the quality of their talks, the awards and scientific committees for their support to the organization of the conference, and finally the topic organizers for reviewing all extended abstracts and selecting the awards nominees.Postprint (published version

Large space structures and systems in the space station era: A bibliography with indexes (supplement 04)

Bibliographies and abstracts are listed for 1211 reports, articles, and other documents introduced into the NASA scientific and technical information system between 1 Jul. and 30 Dec. 1991. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems