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Publicações

2018

On the Fly Reporting of Human Body Movement based on Kinect v2

Autores
Rodrigues, J; Maia, P; Choupina, HMP; Cunha, JPS;

Publicação
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS

Abstract
Human gait analysis is of utmost importance in understanding several aspects of human movement. In clinical practice, characterizing movement in order to obtain accurate and reliable information is a major challenge, and physicians usually rely on direct observation in order to evaluate a patient's motor abilities. In this contribution, a system that can objectively analyze the patients gait and generate an on the fly, targeted and optimized gait analysis report is presented. It is an extension to an existing system that could be used without interfering with the healthcare environment, which did not provide any on the fly feedback to physicians. Patient data are acquired using Kinect v2, followed by data processing, gait specific feature extraction, ending with the generation of a quantitative on the fly report. To the best of our knowledge, the complete system fills the gap as a proper gait analysis system, i.e., a low-cost tool that can be applied without interfering with the healthcare environment, provide quantitative gait information and on the fly feedback to physicians through a motion quantification report that can be useful in multiple areas. © 2018 IEEE.

2018

PSO Evolution Based on a Entropy Metric

Autores
Solteiro Pires, EJ; Tenreiro Machado, JA; Moura Oliveira, PBd;

Publicação
HIS

Abstract
Bioinspired search algorithms are widely used for solving optimization problems. The evolution progress isusially measured by the fitness value of the population fittest element. The search stops when the algorithm reaches a predetermined number of iterations, or when no improvement is achieved after some iterations. Usually, no information, behind the best global objective value, is fed into the algorithm to influence its behavior. In this paper, a entropy metric is proposed to measure the algorithm convergence. Several experiments are carried out using a particle swarm optimization to analyze the metric relevance. Moreover, the proposed metric is used to implement a strategy to prevent premature convergence to suboptimal solutions. The results show that the index is useful for analyzing and improving the algorithm convergence during the evolution.

2018

Internationalization in Business-to-Business Markets

Autores
Moreira, AC; Freitas da Silva, PM;

Publicação
Handbook of Research on Entrepreneurial Ecosystems and Social Dynamics in a Globalized World - Advances in Business Strategy and Competitive Advantage

Abstract
The internationalization of firms is a growing important phenomenon in the Economy. Thus, to face the new competitive challenges of globalized markets, industrial small and medium-sized enterprises (SMEs) need to implement new organizational approaches to take on new challenges in international markets. Based on a case study, this chapter reviews the literature on internationalization theories. Drawing on the network-based approach and on the resource-based view of the firm, we examine how collaborative new product development processes played a fundamental role in the internationalization process of a SME using a relationship-based perspective. The featured case concerns to a successful ex-small technical textile firm that leveraged its competitive strategy, climbed up the value chain, and extended its international activities following a technology-based path.

2018

Dynamic Dyadic Green Function Method for Modeling of Heat Transfer in Metamaterials

Autores
Mariji, H; Maslovski, SI;

Publicação
METAMATERIALS XI

Abstract
In order to model the heat transfer dynamics in metamaterials (MMs), we develop a self-consistent theoretical formalism that combines the photonic mechanism, which involves the effects of the radiative heat transfer, with the phononic one, which comprises the effects of heat generation, heat storage, and heat conduction. The thermal conductivity tensor of the materials and the latent heat associated with material phase transitions are also considered in the formalism. As the first attempt in the construction of such a theory, here we study the propagation of fluctuating electromagnetic fields with slowly varying amplitudes (FEFSVA) through a dispersive and dissipative medium described by uniaxial effective permittivity and permeability tensors. Using the Poynting theorem for FEFSVA, we calculate the corresponding heat generation, accumulation, and release terms in a generalized heat transport equation. The dynamics of FEFSVA and its relation to the fluctuating source currents is described by constructing the matrix of dynamic dyadic Green's functions. In the framework of the fluctuation-dissipation theorem, we obtain correlation between the 6-vector fluctuating current densities with SVA through relating the power spectral density of these currents to the local temperature and the frequency-dependent constitutive parameters in a narrow band around the carrier frequency. With a motivation in the study of how the slowed down FEFSVA impacts on the heat conduction, we employ our formalism in order to obtain the group velocity of the FEFSVA propagating through a layered hyperbolic MM with the Drude type dispersion.

2018

Poses Optimisation Methodology for High Redundancy Robotic Systems

Autores
Tavares, P; Costa, P; Veiga, G; Moreira, AP;

Publicação
ROBOT 2017: THIRD IBERIAN ROBOTICS CONFERENCE, VOL 2

Abstract
The need for efficient automation methods has prompted the fast development in the field of Robotics. However, most robotic solutions found in industrial environments lack in both flexibility and adaptability to be applied to any generic task. A particular problem arises when robots are integrated in work cells with extra degrees of freedom, such as external axis or positioners. The specification/design of high redundancy systems, including robot selection, tool and fixture design, is a multi-variable problem with strong influence in the final performance of the work cell. This work builds on top of optimisation techniques to deal with the optimal poses reachability for high redundancy robotic systems. In this paper, it will be proposed a poses optimisation approach to be applicable within high redundancy robotic systems. The proposed methodology was validated by using real environment existent infrastructures, namely, the national CoopWeld project.

2018

An Innovative Two-Level Model for Electric Vehicle Parking Lots in Distribution Systems With Renewable Energy

Autores
Shafie Khah, M; Siano, P; Fitiwi, DZ; Mahmoudi, N; Catalao, JPS;

Publicação
IEEE TRANSACTIONS ON SMART GRID

Abstract
With the rapid growth of electric vehicles (EVs) in distribution systems, a new player, called EV parking lot operator (EV PLO), is emerging around the world. Furthermore, the integration of distributed generation in the distribution level, in particular, renewable energy sources, is leading to the establishment of various markets in distribution systems. On one hand, such PLOs aim at managing their EVs within their parking lots to participate in the distribution markets and to maximize their profits. On the other hand, a distribution system operator seeks to minimize the system-wide cost while minimizing renewable power spillage and the side-effects of its intermittency. This interaction inspires the innovative two-level model proposed in this paper. In the first level, a new model is proposed for EV PLOs which models the EVs' characteristics, including EV owners' uncertainties, in a reasonably accurate manner. These PLOs are allowed to participate in energy, reserve and regulation distribution markets by optimally managing their EVs. In the second level, a new model is developed to ensure that the technical constraints in the distribution networks are met while minimizing the overall system cost. In addition, this paper evaluates the effects of the penetration level and the placement of wind and solar PV on the offering strategies of EV parking lots, as well as on the overall performance of the distribution systems.

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