Sökning: "Fundamental Limitations"

Visar resultat 1 - 5 av 149 avhandlingar innehållade orden Fundamental Limitations.

  1. 1. Fundamental Limitations of Distributed Feedback Control in Large-Scale Networks

    Författare :Emma Tegling; Henrik Sandberg; Ali Jadbabaie; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Distributed control; Large-scale systems; networked control; decentralized control; fundamental limitations; networked systems; frequency control; smart grid; consensus; spatial invariance; power system dynamics; microgrids; vehicular formation systems; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Networked systems accomplish global behaviors through local feedback interactions. The purpose of a distributed control design is to select interaction rules and control protocols that achieve desired global control objectives. LÄS MER

  2. 2. Quantitative Tracer Based MRI Perfusion : Potentials and Limitations

    Författare :Arvid Morell; Atle Bjørnerud; Håkan Ahlström; Linda Knutsson; Uppsala universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MRI; Perfusion; Contrast agent; Relaxivity; Radiology; Radiologi;

    Sammanfattning : Tracer based MRI perfusion measurements is a clinically useful tool to assess regional distributions of tissue blood flow and volume. The method may be based on any of the three relaxation mechanisms T1, T1 and T2*, the latter denoted DSC-MRI being the most common. LÄS MER

  3. 3. Fundamental Control Performance Limitations for Interarea Oscillation Damping and Frequency Stability

    Författare :Joakim Björk; Karl H. Johansson; Lennart Harnefors; Joe H. Chow; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Power system control; HVDC transmission control; interarea oscillations; power oscillation damping; small-signal stability; fundamental control limitations; frequency stability; hydro power; wind power; non-minimum phase; zero dynamics; eigenvalue analysis; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : With the transition towards renewable energy and the deregulation of the electricity markets, the power system is changing. Growing electricity demand and more intermittent power production increase the need for transfer capacity. Lower inertia levels due to a higher share of renewables increase the need for fast frequency reserves (FFR). LÄS MER

  4. 4. Limitations on efficiency, size and bandwidth of small antennas

    Författare :Daniel Nyberg; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; log-periodic antennas; Small antennas; folded dipoles; radiation Q; fundamental limitations; bandwidth;

    Sammanfattning : The allocated space in a mobile phone for the antennas has become smaller and smaller following the size reduction of the mobile phones themselves and the integration of more functions in them. At the same time new communication systems are being planned where such small antennas also need to be wideband (UWB systems) or have multiple ports (MIMO systems). LÄS MER

  5. 5. On performance limitations of large-scale networks with distributed feedback control

    Författare :Emma Tegling; Henrik Sandberg; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Networked control systems; microgrids; platooning; vehicular formation; multi-agent systems; H2 norms; fundamental limitations; consensus; Distributed control; large-scale networks; oscillator networks; power networks; power system dynamics; system performance; spatially invariant systems; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : We address the question of performance of large-scale networks with distributed feedback control. We consider networked dynamical systems with single and double integrator dynamics, subject to distributed disturbances. We focus on two types of problems. First, we consider problems modeled over regular lattice structures. LÄS MER