Sökning: "frekvensanalys"

Visar resultat 1 - 5 av 6 avhandlingar innehållade ordet frekvensanalys.

  1. 1. Modeling of Modular Multilevel Converters for Stability Analysis

    Författare :Luca Bessegato; Stefan Östlund; Staffan Norrga; Lennart Harnefors; Xiongfei Wang; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Modular multilevel converters MMCs ; stability; admittance; frequency-domain analysis; linearization techniques; current control; voltage control; ac ac converters; railway engineering.; Modulära multinivåomvandlare MMC ; stabilitet; admittans; frekvensanalys; linjäriseringsmetoder; strömreglering; spänningsreglering; ac ac omvandlare; järnvägsteknik.; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Modular multilevel converters (MMCs) have recently become the state-of-the-art solution for various grid-connected applications, such as high-voltage direct current (HVDC) systems and flexible alternating current transmission systems (FACTS). Modularity, scalability, low power losses, and low harmonic distortion are the outstanding properties that make MMCs a key technology for a sustainable future. LÄS MER

  3. 2. Spectral Analysis for Signal Detection and Classification : Reducing Variance and Extracting Features

    Författare :Isabella Reinhold; Statistical Signal Processing Group; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multifönster; Tids-frekvensanalys; Instantaneous frequency; Multitaper; Signal resolution; Reassignment method; Time-frequency analysis;

    Sammanfattning : Spectral analysis encompasses several powerful signal processing methods. The papers in this thesis present methods for finding good spectral representations, and methods both for stationary and non-stationary signals are considered. LÄS MER

  4. 3. Flood Hazard Assessment in Data-Scarce Basins : Use of alternative data and modelling techniques

    Författare :Diana Fuentes-Andino; Sven Halldin; Chong-Yu Xu; Keith Beven; Giuliano Di Baldassarre; Wouter Buytaert; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Central America; floods; data scarcity; data quality; uncertainty analysis; regionalisation; flood frequency analysis; GLUE; hydraulic modelling; rainfall-runoff modeling; TOPMODEL; LISFLOOD-FP; GRADEX; index-flood; Muskingum-Cunge-Todini flow routing; Mellanamerika; högflöde; datakvalitet; osäkerhetsanalys; regionalisering; frekvensanalys av högflöden; GLUE; hydraulisk modellering; nederbörds-avrinningsmodeller; TOPMODEL; LISFLOOD-FP; GRADEX; indexflöde; Muskingum-Cunge-Todini flödessvarstid; Central América; inundaciones; escasez de datos; calidad de los datos; análisis de incertidumbre; regionalización; análisis de frequencia de inundación; GLUE; modelación hidraulica; modelo de lluvia-escorrentía; TOPMODEL; LISFLOOD-FP; GRADEX; índice de inundación; Muskingum-Cunge-Todini rutina de propagación de flujo;

    Sammanfattning : Flooding is of great concern world-wide, causing damage to infrastructure, property and loss of life. Low-income countries, in particular, can be negatively affected by flood events due to their inherent vulnerabilities. Moreover, data to perform studies for flood risk management in low-income regions are often scarce or lacking sufficient quality. LÄS MER

  5. 4. Automated Bottleneck Analysis of Production Systems : Increasing the applicability of simulation-based multi-objective optimization for bottleneck analysis within industry

    Författare :Jacob Bernedixen; Amos H. C. Ng; Anna Syberfeldt; Kalyanmoy Deb; Leif Pehrsson; Magnus Wiktorsson; Högskolan i Skövde; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; bottleneck analysis; bottleneck identification; bottleneck improvement; multi-objective optimization; simulation; Production and Automation Engineering; Produktion och automatiseringsteknik;

    Sammanfattning : Manufacturing companies constantly need to explore new management strategies and new methods to increase the efficiency of their production systems and retain their competitiveness. It is of paramount importance to develop new bottleneck analysis methods that can identify the factors that impede the overall performance of their productionsystems so that the optimal improvement actions can be performed. LÄS MER

  7. 5. Artificial neural networks classify myocardial perfusion images

    Författare :Dan Lindahl; Lund Klinisk fysiologi; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; tomography; radiology; Clinical physics; radionuclide imaging; ischemic heart disease; computer-assisted diagnosis; medical instrumentation; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering;

    Sammanfattning : In the studies of this thesis, a method for automated classification of myocardial perfusion images was successfully developed and evaluated. The results show that the method, based on artificial neural networks, was equally good, or even better than human experts. LÄS MER