2020
Autores
Norouzizad, A; Bahramara, S; Divian, A; Osorio, GJ; Shafie khah, M; Wang, F; Catalao, JPS;
Publicação
2020 IEEE INDUSTRY APPLICATIONS SOCIETY ANNUAL MEETING
Abstract
The use of distributed generators (DGs) in the distribution networks has many economic and technical advantages. In order to achieve these advantages, DGs should have the proper size and be installed in suitable locations. In this work, a differential evolution algorithm is proposed to find the best location and capacity of DGs in the distribution network with the aim of getting to the minimum losses and optimal voltage profile. The important loads need continuity of power supply when the network is in islanding mode due to various events such as short circuit faults. The existence of at least one DG in these networks is necessary. In this paper, the proposed method is applied to the IEEE 33-bus distribution network in two connection modes. First, it is connected with the power grid and then it works in the islanding operation mode. The results show the effectiveness of the proposed algorithm.
2020
Autores
Dexter, J; Shangguan, J; Honig, S; Kishimoto, M; Lutz, D; Netzer, H; Davies, R; Sturm, E; Pfuhl, O; Amorim, A; Baubock, M; Brandner, W; Clenet, Y; de Zeeuw, PT; Eckart, A; Eisenhauer, F; Schreiber, NMF; Gao, F; Garcia, PJV; Genzel, R; Gillessen, S; Gratadour, D; Jimenez Rosales, A; Lacour, S; Millour, F; Ott, T; Paumard, T; Perraut, K; Perrin, G; Peterson, BM; Petrucci, PO; Prieto, MA; Rouan, D; Schartmann, M; Shimizu, T; Sternberg, A; Straub, O; Straubmeier, C; Tacconi, LJ; Tristram, K; Vermot, P; Waisberg, I; Widmann, F; Woillez, J;
Publicação
ASTRONOMY & ASTROPHYSICS
Abstract
We use VLTI/GRAVITY near-infrared interferometry measurements of eight bright type 1 AGN to study the size and structure of hot dust that is heated by the central engine. We partially resolve each source, and report Gaussian full width at half-maximum sizes in the range 0.3-0.8 mas. In all but one object, we find no evidence for significant elongation or asymmetry (closure phases less than or similar to 1 degrees). The narrow range of measured angular sizes is expected given the similar optical flux of our targets, and implies an increasing effective physical radius with bolometric luminosity, as found from previous reverberation and interferometry measurements. The measured sizes for Seyfert galaxies are systematically larger than for the two quasars in our sample when measured relative to the previously reported R & x2004;similar to & x2004;L-1/2 relationship, which is explained by emission at the sublimation radius. This could be evidence of an evolving near-infrared emission region structure as a function of central luminosity.
2020
Autores
Silva, D; Azevedo, A;
Publicação
International Journal of Integrated Supply Management
Abstract
Sustainable development is a widely spread concept nowadays, especially due to external pressure related to environmental and social issues, affecting all players of the supply chain. Sustainable policies must be adopted, such as improving process performance and reducing waste. With sustainability as a driver of operational excellence, this study is focused on the improvement of the production process of a company by reducing variability. A variability analysis was done to understand its root causes and act upon them, as well as a quantification of waste in the process. Finally, an improvement plan was delineated to mitigate the problems identified. Copyright © 2020 Inderscience Enterprises Ltd.
2020
Autores
Almeida, J; Matias, B; Ferreira, A; Almeida, C; Martins, A; Silva, E;
Publicação
SENSORS
Abstract
Emerging opportunities in the exploration of inland water bodies, such as underwater mining of flooded open pit mines, require accurate real-time positioning of multiple underwater assets. In the mining operation scenarios, operational requirements deny the application of standard acoustic positioning techniques, posing additional challenges to the localization problem. This paper presents a novel underwater localization solution, implemented for the VAMOS! project, based on the combination of raw measurements from a short baseline (SBL) array and an inverted ultrashort baseline (iUSBL). An extended Kalman filter (EKF), fusing IMU raw measurements, pressure observations, SBL ranges, and USBL directional angles, estimates the localization of an underwater mining vehicle in 6DOF. Sensor bias and the speed of sound in the water are estimated indirectly by the filter. Moreover, in order to discard acoustic outliers, due to multipath reflections in such a confined and cluttered space, a data association layer and a dynamic SBL master selection heuristic were implemented. To demonstrate the advantage of this new technique, results obtained in the field, during the VAMOS! underwater mining field trials, are presented and discussed.
2020
Autores
Mesquita, IA; Pereira da Fonseca, PFP; Borgonovo Santos, M; Ribeiro, E; Vieira Pinheiro, ARV; Correia, MV; Silva, C;
Publicação
HUMAN MOVEMENT SCIENCE
Abstract
Introduction: Recently, kinematic analysis of the drinking task (DRINK) has been recommended to assess the quality of upper limb (UL) movement after stroke, but the accomplishment of this task may become difficult for poststroke patients with hand impairment. Therefore, it is necessary to study ADLs that involve a simpler interaction with a daily life target, such as the turning on a light task (LIGHT). As the knowledge of movement performed by healthy adults becomes essential to assess the quality of movement of poststroke patients, the main goal of this article was to compare the kinematic strategies used by healthy adults in LIGHT with those that are used in DRINK. Methods: 63 adults, aged 30 to 69 years old, drank water and turned on a light, using both ULs separately, while seated. The movements of both tasks were captured by a 3D motion capture system. End-point and joint kinematics of reaching and returning phases were analysed. A multifactorial analysis of variance with repeated measures was applied to the kinematic metrics, using age, sex, body mass index and dominance as main factors. Results: Mean and peak velocities, index of curvature, shoulder flexion and elbow extension were lower in LIGHT, which suggests that the real hand trajectory was smaller in this task. In LIGHT, reaching was less smooth and returning was smoother than DRINK. The instant of peak velocity was similar in both tasks. There was a minimal anterior trunk displacement in LIGHT, and a greater anterior trunk displacement in DRINK. Age and sex were the main factors which exerted effect on some of the kinematics, especially in LIGHT. Conclusion: The different target formats and hand contact in DRINK and LIGHT seem to be responsible for differences in velocity profile, efficiency, smoothness, joint angles and trunk displacement. Results suggest that the real hand trajectory was smaller in LIGHT and that interaction with the switch seems to be less demanding than with the glass. Accordingly, LIGHT could be a good option for the assessment of poststroke patients without grasping ability. Age and sex seem to be the main factors to be considered in future studies for a better match between healthy and poststroke adults.
2020
Autores
Ferreira, F; Gago, M; Mollaei, N; Bicho, E; Sousa, N; Gama, J; Ferreira, C;
Publicação
INTERNATIONAL CONFERENCE ON NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2019
Abstract
The goal of this study was grouping patients with parkinsonism that share similar gait characteristics based on principal component analysis (PCA). Spatiotemporal gait data during self-selected walking were obtained from 15 patients with Vascular Parkinsonism, 15 patients with Idiopathic Parkinson's Disease and 15 Controls. PCA was used to reduce the dimensionality of 12 gait characteristics for the 45 subjects. Fuzzy C-mean cluster analysis was performed plotting the first two principal components, which accounted for 84.1% of the total variability. Results indicates that it is possible to quantitatively differentiate different gait types in patients with parkinsonism using PCA. Objective graphical classification of gait patterns could assist in clinical evaluation as well as aid treatment planning.
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