267 research outputs found

    A supervisory approach to microgrid demand response and climate control

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    Microgrids equipped with small-scale renewable-energy generation systems and energy storage units offer challenging opportunity from a control point of view. In fact, in order to improve resilience and enable islanded mode, micro-grid energy management systems must dynamically manage controllable loads by considering not only matching energy generation and consumption, but also thermal comfort of the occupants. Thermal comfort, which is often neglected or oversimplified, plays a major role in dynamic demand response, especially in front of intermittent behavior of the renewable energy sources. This paper presents a novel control algorithm for joint demand response management and thermal comfort optimization in a microgrid composed of a block of buildings, a photovoltaic array, a wind turbine, and an energy storage unit. In order to address the large-scale nature of the problem, the proposed control strategy adopt a two-level supervisory strategy: at the lower level, each building employs a local controller that processes only local measurements; at the upper level, a centralized unit supervises and updates the three controllers with the aim of minimizing the aggregate energy cost and thermal discomfort of the microgrid. Comparisons with alternative strategies reveal that the proposed supervisory strategy efficiently manages the demand response so as to sensibly improve independence of the microgrid with respect to the main grid, and guarantees at the same time thermal comfort of the occupants.Accepted Author ManuscriptTeam Bart De Schutte

    Experiences with coastal and maritime UAS BLOS operation with phased-array antenna digital payload data link

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    submittedVersion(c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works

    Ground, Ceiling and Wall Effect Evaluation of Small Quadcopters in Pressure-controlled Environments

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    Multicopters are used for a wide range of applications that often involve approaching buildings or navigating enclosed spaces. Opposed to the open spaces in obstacle-free environments commonly flown by fixed-wing unmanned aerial vehicles, multicopters frequently fly close to surfaces and must take into account the airflow variations caused by airflow rebound. Such disturbances must be identified in order to design algorithms capable of compensating them. The evaluation of ground, ceiling and wall effects using two different test stands is proposed in this work. Different propellers and sensors have been considered for testing. The first test setup used was placed inside terraXcube's large climatic chamber allowing a precise control of temperature and pressure of around 20 degrees C and 1000 hPa, respectively. The second test setup is located at the University of Denver (DU) Unmanned Systems Research Institute (DU2SRI) laboratory with a stable pressure of around 800 hPa. Two different fixed 6 degrees of freedom force-torque sensors have been used for the experiments, allowing to sample forces and moments in three orthogonal axes. The tests simulate a hovering situation of a quadcopter at different distances to either the ground, the ceiling or a wall. The influence of the propeller size, rotation speed, pressure and temperature have also been considered and used for later dimensionless coefficient comparison. A thorough analysis of the measurement uncertainty is also included based on experimental evaluations and manufacturer information. Experimental data collected in these tests can be used for the definition of a mathematical model in which the effect of the proximity to the different surfaces is evaluated

    A pan-tilt camera Fuzzy vision controller on an unmanned aerial vehicle

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    is paper presents an implementation of two Fuzzy Logic controllers working in parallel for a pan-tilt camera platform on an UAV. This implementation uses a basic Lucas-Kanade tracker algorithm, which sends information about the error between the center of the object to track and the center of the image, to the Fuzzy controller. This information is enough for the controller, to follow the object moving a two axis servo-platform, besides the UAV vibrations and movements. The two Fuzzy controllers of each axis, work with a rules-base of 49 rules, two inputs and one output with a more significant sector defined to improve the behavior of those

    Peripheral large or giant fusiform middle cerebral artery aneurysms: report of our experience and review of literature

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    Peripheral large and giant middle cerebral artery (MCA) aneurysms are rare and difficult to treat. We report our and others’ experience with different possible modalities used to treat such lesions. Three patients were treated differently at our institution. One harboured a giant fusiform aneurysm on a peripheral branch of the superior trunk of the left MCA, and was treated by extracranial-intracranial (EC-IC) bypass and trapping of the aneurysm. The second patient was harbouring a large fusiform aneurysm on a peripheral branch of the inferior trunk of the right MCA, which was treated by trapping and excision without the need of an EC-IC bypass as assessed pre- and intraoperatively, while the last case was harbouring a giant fusiform aneurysm at the junction of M2-M3 and was treated by EC-IC bypass and end-to-end anastomosis after resection of the aneurysm. The aneurysms proved to be neither mycotic nor dissecting. The patients were clinically intact during their perioperative course without any postoperative complications and required no further treatment. Follow-up angiography demonstrated a functioning EC-IC bypass. Based on the surgical experience in these 3 cases and a review of the reported literature, the authors propose that when considering surgical treatment for such rarely encountered aneurysms, careful pre- and intraoperative evaluation including aneurysm trapping with or without EC-IC bypass when possible should be performed to obtain a satisfactory result without complication
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