|
|
Extraction of impedance model circuit parameters and its emulation
Semenov, Dmitrii ; Brančík, Lubomír (referee) ; Šotner, Roman (advisor)
V této bakalářské práci byly představeny dva optimalizační algoritmy v MATLABu: první je pro extrahování nul/pólů, jejích počtu a frekvence celočíselných kořenu přenosových funkcí s komplexním kmitočtem "s". Tento algoritmus byl ověřen na aktivních a pasivních filtrech typů Pásmová Propust (PP), Pásmová Zadrž (PZ) a bilineárních sekcích. Druhý algoritmus aproximuje fraktální přenosové charakteristiky s určitým (nastavitelným uživatelem) počtem nul/pólů pomocí optimalizace "roje včel". Tento algoritmus byl ověřen na vzorku bioimpedance, jako je pomerančová šťáva. Vlastní testovací deska plošného spoje (DPS) emulátoru, která je založená na vlastních Operačních Transkonduktančních Zesilovačích (OTA), které jsou vyrobené v procesu I3T25 350nm, byla vyvinuta pro emulaci charakteristik bioimpedance s parametry extrahovanými pomocí algoritmu. Výsledky emulace byly poté porovnány z hlediska přesnosti s komerčním softwarem NOVA Metrohm pro elektrochemickou analýzu.
|
|
|
Design of a measuring unit for smart agriculture
Kostelanská, Alžbeta ; Kubánek, David (referee) ; Herencsár, Norbert (advisor)
The Master's thesis is dealing with the design of an intelligent measuring unit aimed at the field of smart agriculture. The proposed measuring unit is intended to provide automated measurements and monitoring of plant conditions utilizing electrical bioimpedance spectroscopy. In the theoretical part of the thesis, the concept of bioimpedance is introduced, the main focus is on the interpretation of its value in the context of agriculture. The practical part of the thesis is dealing with the design and implementation of a prototype impedance analyzer which utilizes an integrated analogue impedance interface. The output of the thesis is a prototype of the measuring unit and an interface for visualization of the measured data. The conclusion of the thesis is devoted to the evaluation of the results of the measurements, which have been conducted by the constructed prototype.
|
|
|
Autonomous Impedance Meter
Voda, Zbyšek ; Mrázek, Vojtěch (referee) ; Vašíček, Zdeněk (advisor)
This thesis deals with design of a smart embedded device for autonomous measurement of impedance optimized for measurement of biological materials. The goal is to create a device which provides a simple web interface which allows users to capture and further analyze measured data. The digital part is based on MT7688 SoC with WiFi capabilities. The analogue part utilizes a single-chip integrated solution AD5933 that is tightly coupled with a custom analogue frontend whose function is to modify the signal to avoid a potential damage of biological samples. The proposed device is able to either measure impedance for a single frequency or perform a frequency sweep across the whole range beginning at 50Hz and ending at 100 kHz. It supports common two-electrode probes as well as more precise four-electrode probes. The analogue frontend has been simulated using the SPICE simulator to avoid a potential design bug. The experimental evaluation shows that the achieved precision for the typical impedance of biological samples is better than 0.5%.
|
|
|
Validaton of multichannel bioimpedance of vessels using synchronized vascular ultrasonography
Hidegová, Simona ; Kolářová, Jana (referee) ; Mézl, Martin (advisor)
The inclusion of a new device in clinical practice requires an adequate validation. The original publication which introduced multichannel bioimpedance monitor MBM was focused on discribing its technical parameters and demonstration measurements. Further evaluation desires comparision with other standard measuring device. This thesis describes pulse wave measurement by MBM and by other medical devices used for establishing cardiovascular risk. It proposes the validation experiment with synchronized vascular ultrasonography as a reference method. The process of the experimental measurement, aquired data and following data analysis are described in detail. The outputs of the experiment are statistically evaluated. The MBM’s performance and design of the experiment are discussed.
|
|
|
Bioimpedance measurement
Pagáčová, Lenka ; Balogh, Jaroslav (referee) ; Sekora, Jiří (advisor)
The work deals with the body analysis using bioimpedance. The work included theory about bioimpedance and methods associated with the analysis. In the practical part is design of the device for measuring body composition including a software for the microcontroller. The assembled device was tested and compared with commercial product Tanita.
|
|
|
An Electro-Hydrodynamic Model for Bioimpedance Plethysmography
Vyroubal, Petr ; Uruba,, Václav (referee) ; Horák,, Vladimír (referee) ; Maxa, Jiří (advisor)
This doctoral thesis deals with the study of electro-hydrodynamics in the area of numerical modelling of biomechanical systems, concretely in the method of bioimpedance plethysmography. Solving tasks of pulsatile blood flow in the elastic vessel wall is currently one of the most complicated problem in mechanics and biomechanics due to the interaction of two continua on the common boundary. The whole system is additionally loaded by diagnostic electric current. This doctoral thesis was created in cooperation with the Institute of Scientific Instruments of the CAS, v. v. i. Brno with the team engaged in medical signals (the leader Ing. Pavel Jurák, CSc.). Experimental measurements were made independently in the St. Anne's University Hospital Brno in the International Clinical Research Center ICRC and in the Mayo Clinic USA.
|
|
|
Conductive model of human tissue for electroporation purposes
Zelinková, Kateřina - Šarlota ; Cipín, Radoslav (referee) ; Novotná, Veronika (advisor)
This thesis solves the issue of the distribution of the high voltage pulse at the electroporation of the arget ablation zone. For futher examination of influence electroporation was necessary to first understand theoretically electrical charakter of cells and replace with basics eletrical circumferential elements (RLC). Based on this knowledge, theoretical prerequisites for experimental measurements were derived. Theoretical assumptions were then verified by experimental measurements. In the measurement, the assumptions found were confirmed, but significant performance losses were identified. A new catheter was designed to reduce the loss. Because the production of a new catheter is not economically disadvantageous, the properties of the new catheter were first tested using the simulation cloud environment SIMSCALE, where the heating of the heart tissue after the application of the electroporation pulse was monitored. Furthermore, the electroporation process was simulated in the FEMM program, where emphasis was placed on the propagation of cardiac tissue tension.
|
|
|
Bioimpedance signal processing
Valíčková, Vladimíra ; Vondra, Vlastimil (referee) ; Soukup, Ladislav (advisor)
Theoretical part of this Bachelor thesis deals with properties measurement and use of bioim-pedance signal for medical diagnostics. The practical part deals with detection of important points in derivate bioimpedance signal that may be further used in various medical applicati-ons. This work compares three detection methods. The best results were achieved by a de-tection with fixed interval there were excluded only 1,09 % values. Very similar results had detector dependent on constant bioimpedance. Here was excreted 1.18 % of detections. Algo-rithms that are dependent on length of RR interval perform worse. Furthermore, there is cal-culated the Pulse wave velocity in six parts of the human body in a horizontal and tilt patient position. In the tilt position were the pulse wave velocity about 38.59 % faster than in hori-zontal.
|
|
|
Properties of pulse wave velocity in human body during various excitations
Matejková, Magdaléna ; Halámek, Josef (referee) ; Vondra, Vlastimil (advisor)
The thesis is concerned with the analysis of measuring pulse wave velocity in human body with the aid of whole-body multichannel bioimpedance which was developed at ISI AS CR, v.v.i.. The evaluation of pulse wave velocity can provide us with important information about the state of vessel compliance which is one of the basic parameters informing on their physiological state. The examination of the state of vascular system is a very important part of early diagnostics because its pathological states are the main contributor to the rise of cardiovascular diseases and disease mortality. The thesis is concerned with the theoretical analysis together with the available methods of valuation of the state of vascular system that use measuring of pulse wave velocity. The main part of the thesis deals with the analysis of the whole-body multichannel bioimpedance measurement. The proposed and programmed protocol that summarizes and visualizes all obtained information is a part of this thesis. This is currently used as an output of the experimental measurement by this method. Data file for statistical processing contains the values of the pulse wave velocity of 35 healthy volunteers and subsequently the properties of pulse wave are assessed at various excitations.
|
|
|
Automatic determination of the pulse wave velocity in a body segment
Kampo, Dávid ; Svačinová, Jana (referee) ; Vondra, Vlastimil (advisor)
This Bachelor´s thesis deals with a propagation of a pulse wave velocity in different body segments and its measurement through bioimpedance. In connection with this topic, the work includes a profound description of a pulse wave and its velocity in regards to diagnostics and prevention of cardiovascular diseases that have been prevailing in recent years. During the process of determination of PWV, ECG is recorded, as it helps to accurately estimate the relevant transition times and the reulting PWV. The main purpose of this work is to validate that PWV can be determined without supportive ECG signals, what as a result makes the whole process simpler, more effective and available. The main target of this work has been successfully achieved and the algorithm for an evaluation of transition times and determination of PWV is described in the work. Moreover, the algorithm is implied to the structure of GUI in Matlab programm where the interface has been designed to suit the user´s needs to analyse PWV. Highlighting the validation process and functionality of the algorithm, signals from 21 subjects have been used to assess some of the most frequent analysed PWVs and all average values of velocities are within a physiological range from 5 m/s to 15 m/s. cfPWV is considered as a golden standard when it comes to PWV and the average value for all 21 subjects has been estimated to 7,54 m/s what corresponds with values from scientific studies that have been assessing cfPWV.
|
guest ::
