Habilitation Thesis Teza de Abilitare - · PDF fileUniversitatea Politehnica Timişoara....

Click here to load reader

  • date post

  • Category


  • view

  • download


Embed Size (px)

Transcript of Habilitation Thesis Teza de Abilitare - · PDF fileUniversitatea Politehnica Timişoara....

  • Universitatea Politehnica Timioara Facultatea de Electronic i Telecomunicaii

    Habilitation Thesis Teza de Abilitare




    Professor, PhD


  • Mihaela Ruxandra Lascu Habilitation Thesis



    (a) Abstract 4

    (b) Achievements and development plans 8

    (c) Scientific, professional and academic achievements 14

    1. Introduction 14

    1.1 Main papers constituting the habilitation thesis 14

    2. Finite element modeling in Electromagnetic Compatibility 15 2.1 The finite element method in shielding problems 15

    2.1.1 Optimal magnetic shielding with grid structures 17 2.1.2 Geometrical models 20 2.1.3 Quickfield models results 22

    2.2 Finite element method applied in modeling perturbations on printed circuit boards 27

    2.2.1 Governing equations of two coupled lines 28 2.2.2 Capacitance and inductance matrix computation 30

    2.3 Measurement Techniques for Determination of Shielding Effectiveness Characterizing Shielded Coaxial Cables 33 2.3.1 Measurement setup. Modified TEM measurement cell 33 2.3.2 TEMMC resonant frequency determination 36

    3. Graphical programming in Biomedical Signal and Image Processing 43 3.1 Biomedical Signal Acquisition and Processing 43

    3.1.1 Data Acquisition 43 3.1.2 LabVIEW for ECG maternal and fetal signal 51

    3.2 Graphical programming in Event Detection using Pan Tompkins Algorithm 57 3.2.1 Filtering for artifacts removal 58 3.2.2 The Pan Tompkins algorithm for QRS detection 64

    3.3 Electrocardiogram Compression and Optimal ECG Filtering Algorithms 67 3.3.1 Neural networks for data compression 70 3.3.2 The Wiener filter 73 3.4 Electrocardiogram Event and Beat Detection 76 3.4.1 QRS detection using adaptive threshold 76 3.5 Real -Time 3D Echocardiography Processing 79 3.5.1 Three dimensional echocardiography processing 79 3.5.2 Image acquisition and processing methods 81 3.6 Feature Extraction in Digital Mammography 85 3.6.1 Mammography as digitized images 85 3.6.2 Image processing techniques 87 3.7 Compression, Noise Removal and Comparison in Digital Mammography 90

  • Mihaela Ruxandra Lascu Habilitation Thesis


    3.7.1 Compression and noise removal 90 3.7.2 Image processing techniques 92 3.7.3 Mammography comparison 95 3.8 A Novel Morphological Image Segmentation with Application in 3D Echographic images 96 3.8.1 Morphological segmentation 97 3.8.2 Real time 3D image processing methodology 101

    4. Graphical programming in Solar, Power Electronics and Modern Education 104 4.1 Solar radiation modeling, measurements and data processing 104 4.1.1 Experimental setup and database 106 4.1.2 Solar irradiation components 107 4.2 Transfer functions calculation in quasiresonant converters 108 4.2.1 Proposed state-space model 109 4.2.2 Transfer functions derivation 110 4.2.3 Verification and applications of the proposed method 112 4.3 E-learning Practical Teaching of Uncontrolled Rectifiers 116 4.3.1 Leonardo Da Vinci Project and its philosophy 117 4.3.2 Module and experiment description 121 4.4 Distance education in soft-switching inverters 125 4.4.1 System requirements and configuration 125 4.4.2 Description of the learning process 126

    (d) Scientific, professional and academic future development plans 131

    (e) References 136

  • Mihaela Ruxandra Lascu Habilitation Thesis



    (a) Abstract The present habilitation thesis summarizes my research activity after the PhD thesis was

    defended in December 1998 at Politehnica University Timisoara. The PhD Thesis was certified by the Ministry of Education and Research, Order no. 3460 / 15. 03. 1999.

    According to the regulations, the first part of this habilitation thesis is represented by the English and Romanian versions of the present abstract.

    A description of the second part is given below. An overview of activity, stressing out the most important research, professional and

    academic achievements: publications list and grants, new courses absorbed in the curricula and contributions to the academic curricula development, taught courses, diploma and dissertation adviser activity, invited professor, students internship, endowed laboratories and library, international cooperation, management activities, etc. The activity can be synthesized by the most important mentioned aspects that are a number of 69 research papers published in the above mentioned period, 23 research grants and 5 books.

    In the following paragraphs a technical presentation regarding four main research topics is provided:

    Electromagnetic compatibility - First a very powerful tool developed by the author for studying the magnetic field of shaped slotted screens is described. The proposed method is based on a circuital characterization of the structure, via the Finite Element Method (FEM) which is then combined with a modal expansion to compute the field inside and outside the border. The next chapter is concerned with predicting the electrical behavior of metallisation patterns printed onto dielectric substrates. It involves the generation of an equivalent circuit to model the electrical properties of the layout. This can be efficiently obtained and directly provided to a circuit simulation program. The last chapter presents a new test procedure for measuring the shielding effectiveness (SE) of shielded coaxial cables. The Transverse Electromagnetic (TEM) modified measurement cell with an asymmetrically placed conductor together with the proposed form of the cell, establish a quasi-uniform field in the zone where the testing cable is placed.

    Graphical programming in biomedical signal and image processing - The first part of this chapter will describe a computer based signal acquisition, processing and analysis system using LabVIEW. Peak detection in electrocardiogram (ECG) is one of the solved problems using LabVIEW and filtering biomedical signals in different ways is a challenge that has to be solved. The next topic presented is graphical programming in event detection using Pan-Tompkins algorithm. QRS and ventricular beat detection is a basic procedure for electrocardiogram (ECG) processing and analysis. Further novel compression techniques are developed for portable heart-monitoring equipment that could also form the basis for more intelligent diagnostic systems thanks to the way the compression algorithms depend on signal classification. Then the design of an optimal Wiener filter is implemented to remove noise from a signal, assuming that the signal is statistically stationary and the noise is a stationary random process that is statistically signal independent. Two programs for compression and Wiener optimal filtering are developed in MATLAB. Also in this chapter a real-time QRS detection

  • Mihaela Ruxandra Lascu Habilitation Thesis


    method implemented in LabVIEW is proposed, based on comparison between absolute values of summed differentiated electrocardiograms of one or more ECG leads and an adaptive threshold. Two algorithms were implemented in LabVIEW. In the last part a real-time 3D echocardiography and the corresponding algorithms that improve the quality of the image are presented. The second image application concerns the compression and noise removal of mammography images because these realize a preprocessing for the identification of microcalcification clusters in mammograms. A non-linear method is implemented in LabVIEW for performing image enhancement. The final chapter reviews ultrasound segmentation methods, in a broad sense, focusing on techniques developed for medical ultrasound images.

    Solar Energy and Power Electronics - The first chapter introduces the first station in Romania (Eastern Europe) outfitted for systematic monitoring of solar irradiance on tilted surfaces. The resulted database is in many aspects unique for Romania, allowing for the first time to derive specific parameters, like diffuse fraction or sunshine number. The second chapter concerns Power Electronics. It is related to small signal transfer functions (control to output and audiosusceptibility) derivation in quasiresonant converters (QRCs). A matrix method based on state-space averaging of the PWM parent converter and switch cell conversion ratio is proposed. The result is general in the sense that the formalism is converter independent. The method was verified for all classical converters and perfect agreement with other tools was obtained.

    E-learning techniques - The first part presents a comparison between classical hands-on laboratories and remote laboratories. Even they are very u