Browsing by Author "Silva, A."
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- Enabling Cyber-Physical Systems for Industry 4.0 operations: A Service Science PerspectivePublication . Dionísio, Andreia; Almeida, Isabel; Silva, AgostinhoBased on the Internet of Things (IoT) and Smart Technologies, manufacturing industries are witnessing the fourth Industrial Revolution, the Industry 4.0 (I4.0), and digital transformation is a keystone in this change. Cyber-Physical Systems (CPS) are strategic in thoroughly digitalizing companies, and I4.0 operations depend on CPS efficiency. Digital plants are held by digital technologies that provide excellent tools for improving product security and supply chain security but requires structured information management to maintain the CPS in its highest level of efficiency. These systems are overly complex and hard to handle when several CPS need to be combined as in a large factory, where several machines must work together to achieve a common goal. This research addresses these issues, and we propose an information management framework of industrial CPS that, towards the industrial efficiency, affords an increase in value for all stakeholders. The framework structures the information through the introduction of two innovative value co-creation concepts: (i) Fingerprint (FP-I4.0), a virtual vehicle that can carry two types of structured information and (ii) Cockpit4.0, an interaction entity between the various service systems, applied from cradle-to-cradle. Validated through the Service Science Theory, we conclude that the proposed empirical framework may boost up CPS efficiency and, from it, I4.0 operations will be more effective
- Flexible-lean processes optimization: A case study in stone sectorPublication . Dionísio, Andreia; Coelho, Luís; Silva, AgostinhoDuring the downturn in demand in Engineering and Construction Architecture (AEC) activities registered in 2007, the Cluster of Mineral Resources of Portugal (CPMR) put into practice an initiative to boost the Ornamental Stone sector, based on incorporating lean thinking concepts, combined with techniques and technologies to make production processes more flexible. This was called the leanstone hornbook (LH). Since then, the LH has been adopted by several Portuguese Ornamental Stone (OS) companies. For these companies, using the LH means changing their operations to a new model based on (i) their participation in R&D consortium projects, (ii) incorporating the resulting innovations, and (iii) combining innovation with lean thinking. Based on a convenience sample of OS companies, the objective of this research was to assess the economic-financial impact of leanstone operations on Portuguese OS companies. Through a methodological framework based on Key Performance Indicators (KPI) and Innovation Outcomes (IO), indexed to companies’ economic-financial performance, LH was found to generate a potentially positive impact in terms of sales volume, exports, investment capacity and net result.
- An iterative pilot-data aided estimator for OFDM-based relay-assisted systemsPublication . Neves, D.; Ribeiro, Carlos; Silva, A.; Gameiro, A.We propose and assess a pilot-data aided channel estimation scheme for realistic relay-assisted scenarios designed for the downlink SFBC OFDM-based systems. We consider that both the base station and the relay node are equipped with an antenna array whereas the user terminal is a single antenna device. The relay protocol considered is equalise-and-forward. The channel estimation method iteratively uses the information carried by the pilots and data to improve the estimate of the equivalent channels for the path Base Station - Relay Node - User Terminal. The MMSE criterion is used in the design of the estimator for both the pilot-based and data-aided iterations. The results show the benefits of cooperation in terms of MSE and also show that the proposed scheme allows, with a single data iteration, a reduction of the number of pilots when compared with non-data-aided schemes.
- Non-Newtonian Blood Flow in Portal Vein with Thrombosis: A Study by Computational Fluid DynamicsPublication . Soares, A. A.; Gonzaga, S.; Silva, José Silvestre; Marinho, D.; Silva, A.; Rouboa, AbelWe investigate the effects on non‐Newtonian blood flow model on the wall shear stress (wss), velocity and viscosity distributions. The 3D Navier‐Stokes equations coupled with viscosity models describing the steady flow in Portal Vein have been solved numerically. Three blood viscosity models (Newtonian, Power‐law and Carreau) are used in numerical simulations. The results highlight the influence of these models on the blood flow and show that the viscosity model of blood may have significant impact on the numerical results especially in the region of the thrombosis.
- A Pilot-Data Based Channel Estimation Method for OFDM Relay-Assisted SystemsPublication . Neves, D.; Ribeiro, C.; Silva, A.; Gameiro, A.In this work we propose and evaluate a pilot and data-based channel estimation scheme for SFBC OFDM-based cooperative scenario. We consider that both the base station and the relay node are equipped with double antenna arrays whereas the user terminal is a single antenna device. The relay protocol considered is equalise-andforward. In this paper we propose a channel estimation method that iteratively uses the information carried by the pilots and data to improve the estimate of the equivalent channels for the path Base Station – Relay Node – User Terminal. The MMSE criterion is used in the design of the estimator for both the pilot-based and data-aided iterations. The proposed method is evaluated in terms of the channel estimation MSE and the results show that the proposed scheme allows, with a single data iteration, a reduction of the number of pilots by a factor of approximately two when compared with non-data-aided schemes.
- Prospetiva 2035 - Três Cenários para o Futuro de Leiria e OestePublication . Silva, Agostinho da; Lopes, Carla; Almeida, Isabel; Carriço, Silvia; Mouga, Teresa; Carriço, Silvia; Siopa, Jorge; Gala, Pedro; Antunes, Mário; Silva, Agostinho; Mouga, Teresa; Lopes, Carla, Alexandra Calado Lopes; Gala, Pedro; Siopa, JorgeA EM@IPLeiria é um think tank criado em 2023 para impulsionar um desenvolvimento sustentável, inovador e competitivo na região de Leiria e Oeste. Mais do que um centro de estudos, é uma fábrica de ideias e soluções, dedicada à análise dos desafios estruturais do território, à identificação de novas oportunidades e ao teste de respostas concretas para problemas reais. Como espaço de cocriação e experimentação, a EM@IPLeiria envolve diversos atores regionais, incluindo autarquias, empresas, instituições de ensino e a sociedade civil, promovendo um modelo de trabalho colaborativo e participativo na construção de estratégias para o futuro. A sua abordagem alia design thinking e prospetiva estratégica, permitindo antecipar tendências, conceber cenários e testar soluções inovadoras antes da sua aplicação em larga escala.
- A Time Domain Channel Estimation Scheme for Equalize-and-Forward Relay-Assisted SystemsPublication . Neves, D.; Ribeiro, C.; Silva, A.; Gameiro, A.In this paper we propose a scheme with a dedicated relay node for an OFDM-based system. We consider an antenna array at the base station and a single antenna at both the user terminal and the relay node. The relay-assisted protocol considered is equalize-and-forward. The proposed scheme requires the computation of parameters which depend on unknown variables at the destination and we show that under some assumptions the scheme is suitable to provide all those requirements. Also, we show that since the pilots at the relay node are properly designed the TD-MMSE estimator can still provide the required channel estimate. The system performance is evaluated by considering a typical pedestrian scenario based on WiMAX specification. The results show that the degradation in the estimator performance is negligible.
- Towards Industry 4.0 | A case study of BIM Deployment in Ornamental Stones SectorPublication . Rabadão, Carlos; Capela, Carlos; Silva, AgostinhoThe transition witnessed from the Third to the Fourth Industrial Age leads to the emergence of paradigms such as BIM, seeking efficiency in Architecture, Engineering and Construction (AEC) through a global approach and procurement oriented towards standardized products and I4.0, where production comes to be supported by Cyber-Physical Systems (CPS). Integrated in the AEC supply chain, the ornamental stone sector shows Portugal to be the eighth country in OS trade worldwide, and the second per capita, with its competitiveness coming from customization BIM represents threats for its business sustainability. Supported by the Service Science, the main objective of this research is to conceptualize an empirical framework, which, when applied to a sample of Ornamental Stone companies, allows a conclusive answer how to keep their competitive advantage of products customization in BIM-standardized procurement environment. By monitoring the entire sequence of events, it was found that the Ornamental Stone companies can retain their main current competitive advantage of customizing their products, which leads us to conclude that Industry 4.0 technologies, appears to respond positively to threat raised from BIM procurement.