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A fuzzy reasoning approach to assess innovation risk in ecosystems
Publication . Abreu, António; Martins, José Moleiro; Calado, João M. F.; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; CTS - Centro de Tecnologia e Sistemas
Currently, companies to be competitive must achieve high rates of innovation and respond quickly to market needs. According to a number of managers and researches innovation is crucial for companies to stay "alive.» Taking into account several reports, the development of co-innovation networks based on a collaborative environment is the best strategy to support innovation projects. However, the absence of mechanisms to detect and even anticipate potential risks of innovation based on a collaborative approach is an obstacle to the proliferation of this way of working. To address this issue, this paper discusses an approach based on fuzzy reasoning for analyzing the level of risk in co-innovation projects. It is discussed how this approach can be applied to co-innovation projects within the context of a collaborative ecosystem. At last, it is discussed the benefits, and challenges found on experimental results from a Portuguese co-innovation network.
Control Charts to Support Trust Monitoring in Dynamic Logistics Networks
Publication . Abreu, António; Requeijo, José; Calado, João M. F.; Dias, Ana; DEMI - Departamento de Engenharia Mecânica e Industrial; UNIDEMI - Unidade de Investigação e Desenvolvimento em Engenharia Mecânica e Industrial
Nowadays, companies to be competitive must develop capabilities that enable them to respond quickly to market needs. According to some managers, the strategy is the development of dynamic logistics networks based on a collaborative environment. However, the absence of mechanisms to detect and even anticipate potential opportunistic behaviour is an obstacle to the proliferation of this way of working. The article aims to understand the role of trust to sustainability of collaborative processes. The paper begins by discussing the trust properties. It is then discussed how statistical control charts can be used to support the trust monitoring of each member within a collaborative ecosystem. The control charts’ tools suggested in this paper are the Z control charts for trust level monitoring and the Zi capacity index. Finally, it is discussed how this approach can be applied to dynamic logistics networks within the context of a collaborative ecosystem.
Semi-analytical approach to vibrations induced by oscillator moving on a beam supported by a finite depth foundation
Publication . Dimitrovová, Zuzana; DEC - Departamento de Engenharia Civil
Structures subject to moving loads have several in rail, road and bridge engineering. When the velocity of the moving system approaches the critical velocity, then the induced vibrations are significantly augmented and safety and stability of the structure as well as of the moving system are compromised. The classical models predict the critical velocity much higher than the one observed in reality, because the wave propagation is restricted to the beam structure. But if the beam is supported by elastic continuum, then the waves can be dominant in the foundation and the interaction with the beam cannot be overlooked. This contribution analyses the critical velocity of an oscillator moving on a beam supported by a foundation of finite depth by semi-analytical methods.
Semi-analytical solution for a problem of a uniformly moving oscillator on an infinite beam on a two-parameter visco-elastic foundation
Publication . Dimitrovová, Zuzana; DEC - Departamento de Engenharia Civil; Elsevier Science B.V., Amsterdam.
In this paper a semi-analytical solution for transverse vibrations induced by a moving oscillator is derived and validated. It is assumed that the oscillator is moving uniformly on an infinite beam, which may be subjected to a normal force, and is supported by a two-parameter visco-elastic foundation. Full evolution of deflection shapes is derived with the help of integral transforms and methods of contour integration. Analytical solution of the problem is presented in the Laplace domain. In the time domain, vibrations are given by a sum of truly steady-state part, induced harmonic part and transient vibration that has generally low importance and rapidly decreasing tendency. Except for the transient vibration, solution is expressed as a finite sum of analytical expressions (sum of residues), of which each has at most one parameter that has to be obtained numerically. With the help of iterative techniques proposed in this paper, these parameters can be easily determined with any precision. These parameters are named as the induced frequencies and as such can identify the onset of unstable behaviour. Thus, derivations in this paper allow to predict not only the onset of instability, but also its severity, which is important for mitigation measures. Transverse vibrations obtained for infinite beams are validated by analyses on long finite beams, exploiting a program written in Matlab software, that was previously validated by finite element software LS-DYNA. The effects of the normal force, Pasternak modulus, harmonic component of the vertical force and foundation damping are discussed.
Earth-fixed trajectory and map online estimation: Building on GES sensor-based SLAM filters
Publication . Lourenço, Pedro; Guerreiro, Bruno J.; Batista, Pedro; Oliveira, Paulo Jorge; Silvestre, Carlos; DEE - Departamento de Engenharia Electrotécnica e de Computadores; CTS - Centro de Tecnologia e Sistemas; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Elsevier Science B.V., Inc
This paper addresses the problem of obtaining an Earth-fixed trajectory and map (ETM), with the associated uncertainty, using the sensor-based map provided by a globally asymptotically/exponentially stable (GES) SLAM filter. The algorithm builds on an optimization problem with a closed-form solution, and its uncertainty description is derived resorting to perturbation theory. The combination of the algorithm proposed in this paper with sensor-based SLAM filtering results in a complete SLAM methodology, which is directly applied to the three main different formulations: range-and-bearing, range-only, and bearing-only. Simulation and experimental results for all these formulations are included in this work to illustrate the performance of the proposed algorithm under realistic conditions. The ETM algorithm proposed in this paper is truly sensor-agnostic, as it only requires a sensor-based map and imposes no constraints on how this map is acquired nor how egomotion is captured. However, in the experiments presented herein, all the sensor-based filters use a sensor to measure the angular velocity and, for the range-only and bearing-only formulations, a sensor to measure the linear velocity.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
5876
Número da atribuição
UID/EMS/50022/2013