Sökning: "dynamic algorithm"

Visar resultat 31 - 35 av 396 avhandlingar innehållade orden dynamic algorithm.

1. 31. Dynamic Analysis of Harmonics in Electrical Systems

   Författare :Erik Möllerstedt; Institutionen för reglerteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Automation; converter control; modeling; linear time periodic systems; frequency domain analysis; harmonics; power systems; small signal stability; robotics; control engineering; Automatiska system; robotteknik; reglerteknik;

   Sammanfattning : Frequency domain analysis and design of power systems is complicated in the presence of harmonics, switching dynamics, nonlinearities, unbalances, and for systems with mixed ac/dc dynamics. The reason is that linearization of the system does not lead to a time invariant system, but a system with periodically time varying dynamics, which implies that there is coupling between different frequencies. LÄS MER

3. 32. Data-driven methods for real-time dynamic stability assessment and control

   Författare :Hannes Hagmar; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Machine learning; Security assessment; Neural networks; Optimal control; Dynamic voltage security margin; Voltage instability prediction; Voltage stability; Deep reinforcement learning;

   Sammanfattning : Electric power systems are becoming increasingly complex to operate; a trend driven by an increased demand for electricity, large-scale integration of renewable energy resources, and new system components with power electronic interfaces. In this thesis, a new real-time monitoring and control tool that can support system operators to allow more efficient utilization of the transmission grid has been developed. LÄS MER

4. 33. Approximate Methods of Optimal Control via Dynamic Programming Models

   Författare :Yuchao Li; Jonas Mårtensson; Karl H. Johansson; Moritz Diehl; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Optimal Control; Dynamic Programming; Rollout; Model Predictive Control; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Optimal control theory has a long history and broad applications. Motivated by the goal of obtaining insights through unification and taking advantage of the abundant capability to generate data and perform online simulation, this thesis studies the discrete-time infinite horizon optimal control problems and introduces some approximate solution methods via abstract dynamic programming (DP) models. LÄS MER

5. 34. Distributed Optimization and Control : Primal--Dual, Online, and Event-Triggered Algorithms

   Författare :Xinlei Yi; Karl H. Johansson; Dimos V. Dimarogonas; John S. Baras; Antonis Papachristodoulou; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Distributed nonconvex optimization; distributed online convex optimization; distributed event-triggered control; primal-dual algorithm; stochastic gradient descent; zeroth-order algorithm; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : In distributed optimization and control, each network node performs local computation based on its own information and information received from its neighbors through a communication network to achieve a global objective. Although many distributed optimization and control algorithms have been proposed, core theoretical problems with important practical relevance remain. LÄS MER

7. 35. Optimisation and Validation of Dynamic Susceptibility Contrast MRI Perfusion Measurements

   Författare :Linda Knutsson; Lund Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Nukleärmedicin; radiobiologi; Nuclear medicine; radiobiology; radiologi; tomografi; medicinsk instrumentering; tomography; medical instrumentation; Clinical physics; cerebral blood volume; mean transit time; cerebral blood flow; perfusion; dynamic susceptibility contrast MRI arterial input function; Klinisk fysiologi; radiology;

   Sammanfattning : The studies presented in this thesis concern the optimisation and evaluation of the dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) technique for the assessment of perfusion-related parameters of the brain, such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT). Several methodological factors influence these measurements, for example, contrast-agent administration, arterial input function (AIF) registration, choice of deconvolution algorithm and the choice of pulse-sequence parameters. LÄS MER