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- Global localization with non-quantized local image featuresPublication . Campos, Francisco M.; Correia, Luís; Calado, João Manuel FerreiraIn the field of appearance-based robot localization, the mainstream approach uses a quantized representation of local image features. An alternative strategy is the exploitation of raw feature descriptors, thus avoiding approximations due to quantization. In this work, the quantized and non-quantized representations are compared with respect to their discriminativity, in the context of the robot global localization problem. Having demonstrated the advantages of the non-quantized representation, the paper proposes mechanisms to reduce the computational burden this approach would carry, when applied in its simplest form. This reduction is achieved through a hierarchical strategy which gradually discards candidate locations and by exploring two simplifying assumptions about the training data. The potential of the non-quantized representation is exploited by resorting to the entropy-discriminativity relation. The idea behind this approach is that the non-quantized representation facilitates the assessment of the distinctiveness of features, through the entropy measure. Building on this finding, the robustness of the localization system is enhanced by modulating the importance of features according to the entropy measure. Experimental results support the effectiveness of this approach, as well as the validity of the proposed computation reduction methods.
- A Fuzzy Logic model to enhance quality management on R&D unitsPublication . Abreu, António; Santos, Ricardo; Calado, João Manuel Ferreira; Requeijo, JoséNowadays, Higher Education Institutions (HEIs), are becoming even more competitive, with the public ones, facing at the same time a greater restriction on public funding. Therefore, HEIs, have to be more effective and more efficient as well, on pursuing their own goals, which includes Research and Development (R&D) units as well. Such demands can be achieved, by enhancing R&D`s global performance. Therefore, the use of a framework such as European Foundation for Quality Management (EFQM), can bring value to an organization with the characteristics of a R&D unit. This work presents a new integrated method based on EFQM model, by using Fuzzy Logic, to enhance the organizations overall performance. The applicability of the proposed approach is demonstrated by a case study in a R&D unit, where an initial performance evaluation takes place, by using RADAR`s Logic approach. The proposed method, based on Fuzzy Logic, is then applied, followed by the identification of the strength points as well as the improvement areas, according to the EFQM framework. Then, the improvement actions with high priority are determined, followed by the correspondent action measures.
- Fault detection approach based on fuzzy qualitative reasoning applied to the DAMADICS benchmark problemPublication . Calado, João Manuel Ferreira; Carreira, F. P. N. F.; Mendes, Mário J. G. C.; Costa, J. M. G. Sá da; Bartys, M.A computer assisted fault detection methodology based on a fuzzy qualitative simulation algorithm is described. The adoption of fuzzy sets allows a more detailed description of physical variables, through an arbitrary, but finite, disaetisatioo of the quantity space. The fuzzy representation of qualitative values is more general than ordinary interval representation, since it can represent not only the information stated by a well defined real interval but also the knowledge embedded in the soft boundaries of the interval. Such a methodology was applied to a pneumatic servomotor actuated control valve that is the benchmark problem of the EC RTN DAMADlCS.
- Complementary filter design with three frequency bands: robot attitude estimationPublication . Carreira, Fernando; Calado, João Manuel Ferreira; Cardeira, Carlos Batista; Oliveira, Paulo Jorge Coelho RamalhoThis paper extents the by now classic sensor fusion complementary filter (CF) design, involving two sensors, to the case where three sensors that provide measurements in different bands are available. This paper shows that the use of classical CF techniques to tackle a generic three sensors fusion problem, based solely on their frequency domain characteristics, leads to a minimal realization, stable, sub-optimal solution, denoted as Complementary Filters3 (CF3). Then, a new approach for the estimation problem at hand is used, based on optimal linear Kalman filtering techniques. Moreover, the solution is shown to preserve the complementary property, i.e. the sum of the three transfer functions of the respective sensors add up to one, both in continuous and discrete time domains. This new class of filters are denoted as Complementary Kalman Filters3 (CKF3). The attitude estimation of a mobile robot is addressed, based on data from a rate gyroscope, a digital compass, and odometry. The experimental results obtained are reported.
- Enhanced PCA-based localization using depth maps with missing dataPublication . Carreira, Fernando; Calado, João Manuel Ferreira; Cardeira, Carlos; Oliveira, PauloIn this paper a new method for self-localization of mobile robots, based on a PCA positioning sensor to operate in unstructured environments, is proposed and experimentally validated. The proposed PCA extension is able to perform the eigenvectors computation from a set of signals corrupted by missing data. The sensor package considered in this work contains a 2D depth sensor pointed upwards to the ceiling, providing depth images with missing data. The positioning sensor obtained is then integrated in a Linear Parameter Varying mobile robot model to obtain a self-localization system, based on linear Kalman filters, with globally stable position error estimates. A study consisting in adding synthetic random corrupted data to the captured depth images revealed that this extended PCA technique is able to reconstruct the signals, with improved accuracy. The self-localization system obtained is assessed in unstructured environments and the methodologies are validated even in the case of varying illumination conditions.
- Aplicação do six sigma business scorecard na gestão de ecossistemas de inovaçãoPublication . Calado, João Manuel Ferreira; Requeijo, José; Abreu, AntónioNo atual contexto, as empresas para serem competitivas têm de desenvolver capacidades de inovação de elevado desempenho que lhes permitam responder rapidamente às necessidades do mercado. No entanto, a ausência de ferramentas e metodologias que permitam avaliar o desempenho dos projetos de inovação de uma forma integrada continua a ser um obstáculo. O artigo começa por discutir os princípios do Six Sigma e do Balanced Scorecard para a avaliação do desempenho. Em seguida, são discutidas as vantagens do Six Sigma Business Scorecard como instrumento de suporte à avaliação do desempenho em projetos de inovação. Por último, são discutidas as vantagens do desenvolvimento no contexto de um ecossistema colaborativo. In the present context, companies to be competitive must develop high-performance innovation capabilities that enable them to respond quickly to market needs. However, the lack of tools and methodologies to assess the performance of innovation projects in an integrated way remains an obstacle. The article begins by discussing the principles of Six Sigma and the Balanced Scorecard for performance evaluation. Next, the advantages of the Six Sigma Business Scorecard are discussed as a tool to support the evaluation of performance in innovation projects. Finally, the advantages of development in the context of a collaborative ecosystem are discussed.
- Management of innovation ecosystems based on six sigma business scorecardPublication . Calado, João Manuel Ferreira; Requeijo, José; Abreu, António; Dias, AnaIn the present context, companies to be competitive must develop high-performance innovation capabilities that enable them to respond quickly to market needs. However, the lack of tools and methodologies to assess the performance of innovation projects in an integrated way remains an obstacle. The paper begins by discussing the principles of Six Sigma and the Balanced Scorecard for performance evaluation. Next, the advantages of the Six Sigma Business Scorecard are discussed as a tool to support the evaluation of performance in innovation projects. Finally, the advantages of their application in the context of a collaborative ecosystem are discussed. It is illustrated that the BSC ensures that top management pays attention at any time to the specific elements of the Six Sigma implementation that are not working as planned, providing a link between strategy and quality initiatives assuring customers satisfaction in innovation projects.
- A gantry robot automatic positioning system using computational visionPublication . Beites, Nuno; Dias, Manuel; Gonçalves Cavaco Mendes, Mário José; Carreira, Fernando; Campos, F.; Calado, João Manuel FerreiraWith the new industrial revolution (industry 4.0) under way, there is a need to automate/digitalize even the simplest processes to keep companies competitive, efficient and secure. This work proposes an automatic and robotic positioning system with position control through the image of video cameras. The objective is to propose this type of automatic system to companies aiming to improve robotic systems operations that are often controlled manually and with associated risks. The developed system was tested in simulation (using Matlab) and in an experimental scale prototype.
- Buildings lean maintenance implementation modelPublication . Abreu, António; Calado, João Manuel Ferreira; Requeijo, JoséNowadays, companies in global markets have to achieve high levels of performance and competitiveness to stay "alive".Within this assumption, the building maintenance cannot be done in a casual and improvised way due to the costs related. Starting with some discussion about lean management and building maintenance, this paper introduces a model to support the Lean Building Maintenance (LBM) approach. Finally based on a real case study from a Portuguese company, the benefits, challenges and difficulties are presented and discussed.
- Fault isolation approach using a PROFIBUS network: a case studyPublication . Mendes, Mário J. G. C.; Kowal, Marek; Calado, João Manuel Ferreira; Korbicz, Józef; Costa, J. M. G. Sá daThis paper presents the second stage, of a two-stage neuro-fuzzy system, used for fault isolation (FI) in dynamic processes and it`s built using a hierarchical structure of fuzzy neural networks. The current approach is tested under a hardware bench constructed with componentes commonly used in the industry and consists on a pilot plant under supervision, a supervision unit, a fault detection and isolation unit and a fault simulation unit. All the elements are connected to a PROFIBUS network, which acts as the communication system for exchanging information between the automation system and the distributed field devices.