Ferramentas Lean na indústria corticeira

O presente projeto tem como objetivo a aplicação de ferramentas do universo Lean Thinking na indústria corticeira de forma a identificar e eliminar fontes de desperdício, criar valor e envolver a organização numa cultura de melhoria contínua focada na satisfação do cliente. A Unidade Industrial de Lamas encontra-se a passar por uma fase de mudança e carece da aplicação de ferramentas 5S, Gestão Visual, Kaizen Diário e Standard Work, contempladas no seu programa de melhoria contínua intitulado de Cork.MAIS. A aplicação das ferramentas comprovam o sucesso em termos de qualidade e eficiência operacional. Os 5S conduzem à eficiência, segurança e organização dos postos de trabalho e quando implementados despoletam de forma natural a necessidade de implementação da ferramenta Gestão Visual que acarreta inúmeros benefícios visto que visa sistemas simples e intuitivos. A ferramenta Kaizen Diário contribuiu para aumentar a comunicação entre os diferentes turnos, alinhar os colaboradores com a estratégia da Unidade Industrial de Lamas e identificar oportunidades de melhoria fomentando o trabalho em equipa. A ferramenta Standard Work contribuiu para a redução dos encravamentos dos equipamentos SVE obtendo-se um aumento de 11% do Overall Equipment Effectiveness. Realizar uma retrospetiva de todos os processos e fluxos de produção tornou-se oportuno e, para tal, recorreu-se à ferramenta Value Stream Mapping. Todo o trabalho em equipa serviria para analisar o estado atual da cadeia de valor da Unidade Industrial de Lamas no que respeita ao planeamento e fluxos de material e informação, metodologia do controlo de produto e processo e eficiência operacional. Todas as oportunidades de melhoria identificadas e implementadas acrescentam valor à cadeia da organização mas dá-se destaque às ações de melhoria implementadas no âmbito do projeto de planeamento e fluxos de informação e material. Todas as novas ferramentas implementadas contempladas no sistema pull da organização conduziram a uma redução de 11% do material em work in process e um aumento de 25% da taxa de satisfação de encomendas.

Network virtualisation from an operator perspective

Network virtualisation is seen as a promising approach to overcome the so-called “Internet impasse” and bring innovation back into the Internet, by allowing easier migration towards novel networking approaches as well as the coexistence of complementary network architectures on a shared infrastructure in a commercial context. Recently, the interest from the operators and mainstream industry in network virtualisation has grown quite significantly, as the potential benefits of virtualisation became clearer, both from an economical and an operational point of view. In the beginning, the concept has been mainly a research topic and has been materialized in small-scale testbeds and research network environments. This PhD Thesis aims to provide the network operator with a set of mechanisms and algorithms capable of managing and controlling virtual networks. To this end, we propose a framework that aims to allocate, monitor and control virtual resources in a centralized and efficient manner. In order to analyse the performance of the framework, we performed the implementation and evaluation on a small-scale testbed. To enable the operator to make an efficient allocation, in real-time, and on-demand, of virtual networks onto the substrate network, it is proposed a heuristic algorithm to perform the virtual network mapping. For the network operator to obtain the highest profit of the physical network, it is also proposed a mathematical formulation that aims to maximize the number of allocated virtual networks onto the physical network. Since the power consumption of the physical network is very significant in the operating costs, it is important to make the allocation of virtual networks in fewer physical resources and onto physical resources already active. To address this challenge, we propose a mathematical formulation that aims to minimize the energy consumption of the physical network without affecting the efficiency of the allocation of virtual networks. To minimize fragmentation of the physical network while increasing the revenue of the operator, it is extended the initial formulation to contemplate the re-optimization of previously mapped virtual networks, so that the operator has a better use of its physical infrastructure. It is also necessary to address the migration of virtual networks, either for reasons of load balancing or for reasons of imminent failure of physical resources, without affecting the proper functioning of the virtual network. To this end, we propose a method based on cloning techniques to perform the migration of virtual networks across the physical infrastructure, transparently, and without affecting the virtual network. In order to assess the resilience of virtual networks to physical network failures, while obtaining the optimal solution for the migration of virtual networks in case of imminent failure of physical resources, the mathematical formulation is extended to minimize the number of nodes migrated and the relocation of virtual links. In comparison with our optimization proposals, we found out that existing heuristics for mapping virtual networks have a poor performance. We also found that it is possible to minimize the energy consumption without penalizing the efficient allocation. By applying the re-optimization on the virtual networks, it has been shown that it is possible to obtain more free resources as well as having the physical resources better balanced. Finally, it was shown that virtual networks are quite resilient to failures on the physical network.