Browsing by Author "Alves, Joel"
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- Energy aware knowledge extraction from Petri nets supporting decision-making in service-oriented automationPublication . Leitão, Paulo; Alves, Joel; Mendes, João M.; Colombo, Armando W.This paper introduces an approach to decision support systems in service-oriented automation control systems, which considers the knowledge extracted from the Petri nets models used to describe and execute the process behavior. Such solution optimizes the decision-making taking into account multi-criteria, namely productive parameters and also energy parameters. In fact, being manufacturing processes typically energy-intensive, this allows contributing for a clean and saving environment (i.e. a better and efficient use of energy). The preliminary experimental results, using a real laboratorial case study, demonstrate the applicability of the knowledge extracted from the Petri nets models to support real-time decision-making systems in service-oriented automation systems, considering some energy efficiency criteria.
- Extraction of knowledge from petri nets models in service oriented based industrial automation systemsPublication . Alves, Joel; Leitão, PauloIn last decades significant changes have been noticed in manufacturing environment, moving from a local economy to a global economy and generalized concurrency. Markets expectations for products with high quality at lower costs, highly customized and with short life cycles, lead us to the need to implement complete different strategies to satisfy these requirements. With the current scenario, technologies have a strong weight in the search of a solution for new manufacturing systems. Service oriented Architectures (SoA) is a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains, which combined with Petri Nets (PN) capabilities of modeling, analysis and simulation and using Web services as communication platform, is one suitable proposal to solve the manufacturing problem and its limitations, granting interoperability, adaptability, flexibility and integration of all the devices that belong to the manufacturing systems. The main objective of this work is to develop mechanisms for the extraction of knowledge from the Petri nets models to support the execution of important control functions, such as monitoring and decision-making. Other objectives can be referred, like the modeling and the assessment of the Petri net models and the creation and improvement of some tools already existent in the area. This work was done during a stage at the Industrial Automation HUB of the Schneider Electric company in Seligenstadt, Germany. All these studied and developed mechanisms were applied to an experimental case study, which allowed us to perform the assessment and the validation of the designed Petri nets models. Nas últimas décadas tem-se assistido a mudanças significativas nos ambientes de fabrico, passando de uma economia local para uma economia global de concorrência generalizada. Nos mercados actuais, a expectativa por produtos de alta qualidade a baixos preços, altamente customizados e com ciclos de vida curtos, conduzem-nos para a necessidade de implementar novas e diferentes estratégias para satisfazer estes requisitos. Neste cenário, as tecnologias têm um grande peso na procura de uma solução para os novos sistemas de fabrico. O Service oriented Architectures (SOA) é um paradigma para organizar e utilizar as suas capacidades de controlo distribuído para ligar diferentes domínios, que combinando com as redes Petri (PN) e aproveitando as capacidades de modelação, análise e simulação, e utilizando os Web Services como plataforma de comunicação, é uma proposta adequada para resolver os problemas dos sistemas de fabrico e suas limitações, garantindo interoperabilidade, adaptabilidade, flexibilidade e integração. O objectivo principal deste trabalho foi o desenvolvimento de mecanismos de extracção de conhecimento dos modelos criados usando o formalismo das Redes de Petri, para servir de apoio à execução das importantes funções de controlo, tais como a monitorização e a tomada de decisão. Outros objectivos que podem ser explícitos são a modelação e avaliação dos modelos em redes de Petri e a criação e aperfeiçoamento de algumas ferramentas já existentes na área. Este trabalho foi realizado durante um estágio, na unidade de Industrial Automation HUB da empresa Schneider Electric em Seligenstadt, Alemanha. Todos os mecanismos estudados e desenvolvidos durante o período de estágio foram aplicados a um caso de estudo experimental, o que nos permitiu fazer a sua avaliação e validação.
- Solving myopia in real-time decision-making using Petri nets models’ knowledge for service-oriented manufacturing systemsPublication . Leitão, Paulo; Alves, Joel; Pereira, Ana I.This paper introduces a novel approach to the real-time decision-making in service-oriented manufacturing systems, addressing the myopia problem usually presented in such systems. The proposed decision method considers the knowledge extracted from the Petri nets models used to describe the services process behavior, mainly the T-invariants, combined with a multi-criteria function customized according to the system’s particularities and strategies. An experimental laboratorial case study was used to demonstrate the applicability of the proposed real-time decision-making approach in service-oriented manufacturing systems, considering some productivity and energy efficiency criteria.