Simultaneous blood perfusion and oxygenation monitoring is crucial for patients undergoing a transplant procedure. This becomes of great importance during the surgical recovery period of a transplant procedure when uncorrected loss of perfusion or reduction in oxygen saturation can result in patient death. Pulse oximeters are standard monitoring devices which are used to obtain the perfusion level and oxygen saturation using the optical absorption properties of hemoglobin. However, in cases of varying perfusion due to hemorrhage, blood clot or acute blockage, the oxygenation results obtained from traditional pulse oximeters are erroneous due to a sudden drop in signal strength. The long term goal of the project is to devise an implantable optical sensor which is able to perform better than the traditional pulse oximeters with changing perfusion and function as a local warning for sudden blood perfusion and oxygenation loss. In this work, an optical sensor based on a pulse oximeter with an additional source at 810nm wavelength has been developed for in situ monitoring of transplant organs. An algorithm has been designed to separate perfusion and oxygenation signals from the composite signal obtained from the three source pulse oximetry-based sensor. The algorithm uses 810nm reference signals and an adaptive filtering routine to separate the two signals which occur at the same frequency. The algorithm is initially applied to model data and its effectiveness is further tested using in vitro and in vivo data sets to quantify its ability to separate the signals of interest. The entire process is done in real time in conjunction with the autocorrelation-based time domain technique. This time domain technique uses digital filtering and autocorrelation to extract peak height information and generate an amplitude measurement and has shown to perform better than the traditional fast Fourier transform (FFT) for semi-periodic signals, such as those derived from heart monitoring. In particular, in this paper it is shown that the two approaches produce comparable results for periodic in vitro perfusion signals. However, when used on semi periodic, simulated, perfusion signals and in vivo data generated from an optical perfusion sensor the autocorrelation approach clearly (Standard Error, SE = 0.03) outperforms the FFT-based analysis (Standard Error, SE = 0.62).

Multicarrier modulation is a transmission technique that is quite convenient for high data rates in wireless communication. Information symbols are partitioned and parallelly sent over multiple narrowband subchannels. Pulse shaping filters are critically important in multicarrier modulation for determining the characteristics of signal in time and frequency domains. In this thesis, we propose a new pulse shaping approach for multicarrier schemes to increase spectral efficiency in multi-user scenarios. Conventionally, the time-frequency lattice and the prototype filter are designed considering the worst-case of time-varying multipath channel. However, this approach ignores to make use of multi-user diversity and leads to excessive spacings between successive symbols in time and frequency. Unlike the prevalent methods, we investigate user-based filter utilization considering the wireless channel of each user individually to prevent over-design and improve spectral efficiency. Also, this approach is implemented in a denser time-frequency lattice design. Symbols are allowed to be overlapped (depending on time-frequency dispersion of their individual channels) as long as the signal-to-interference ratios (SIRs) observed by all users are kept above a certain level. Employing user-specific filters to enhance SIR of the user exposed to the most interference provides more overlapping flexibility. Therefore, further improvement in spectral efficiency is achieved in our wireless communication system design.

In this bachelor thesis, the possiblity to correct for room acousticsbased on frequency analysis is studied. A software to calculate transferfunctions online was constructed and tested. This was done using a ver-sion of the Maximum Length Sequence method, which is a method thatrequires long sequences for rooms with long reverberation. During theproject, it was noted that zero padding the sequences improved the ac-curacy greatly, it was also noted that the length of the zero pad aectedthe results. The software was tested both in computer simulations andin practice. While testing in practice, it was noted that the system haslimitations on which rooms it would work in. All testsignals were recordedand afterwards, compared to the original recording. The constructed soft-ware showed, that it is possible to correct for unknown transfer functionsusing only frequency analysis, to some extent. Further, it does correct forthe room's transfer function, but it is dicult to say if it this is valid forall rooms and transfer functions.

[pt] Nesta tese é abordada a transmissão CDMA (Code Division Multiple Access) por blocos em canais SISO (Single Input - Single Output) seletivos em frequência. Considera-se a transmissão tanto em portadora única quanto multiportadora, com intervalo de guarda do tipo prefixo cíclico e do tipo preenchimento de zeros. São investigadas estruturas de detecção multiusuário às cegas, baseadas no critério de míınima variância com restrições lineares. Implementações adaptativas do tipo gradiente estocástico e do tipo míınimos quadrados são apresentadas e novos algoritmos de estimação de canal são propostos. É também discutida nesta tese a transmissão CDMA por blocos em canais MISO (Multiple Input - Single Output) seletivos em frequência. Considera-se, assim como no canal SISO, os casos de transmissão em portadora única e multiportadora, incorporando intervalos de guarda do tipo prefixo cíclico e do tipo preenchimento de zeros. Para este tipo de sistema, duas estruturas de transmissão são propostas e uma análise do ganho de diversidade para cada tipo de estrutura é conduzido, identificando as condiçõoes para atingir o máximo ganho de diversidade. Um detector baseado no critério de mínimo erro quadrático médio é implementado para cada estrutura e, no caso da primeira estrutura de transmissão, um detector às cegas baseado no critério de mínima variância é proposto. Uma implementação adaptativa do tipo mínimos quadrados é apresentada e novos algoritmos de estimação de canal são propostos. / [en] This thesis addresses block CDMA (Code Division Multiple Access) transmission in frequency selective SISO (Single Input - Single Output) channels. Both multicarrier and single carrier transmission are considered with cyclic prefix and zero padding as guard interval. Blind multiuser detection based on the linearly constrained minimum variance criterion is investigated. Stochastic gradient and recursive least squares implementations are presented and new channel estimation algorithms are proposed. It is also discussed in this thesis block CDMA transmission in frequency selective MISO (Multiple Input - Single Output) channels, including, as in the SISO channel, the case of multicarrier and single carrier transmission with cyclic prefix and zero padding as guard interval. Two structures are proposed for transmission in this scenario, an analysis of the diversity gain for each type of structure is conducted and conditions for achieving the maximum diversity gain are identified. A detector based on the minimum mean square error criterion is implemented for each structure. Recursive least squares implementations are presented and new blind channel estimation algorithms are proposed.

[pt] A necessidade pela transmissão em altas taxas, por exemplo nos novos sistemas de TV Digital de alta definição, telefonia celular de terceira e quarta geração, DSL e etc, trazem consigo um problema: o aumento dos múltiplos percursos no canal de comunicações (principalmente nas interfaces áereas), dando origem ao fenômeno de interferência intersimbólica (IES). Este trabalho investiga o desempenho de sistemas de transmissão com uma única portadora (SC ou single-carrier) com equalização linear no domínio da freqüência. Diferentes algoritmos recursivos são apresentados para implementar estes filtros FIR. Além dos equalizadores lineares, uma estrutura não-linear é introduzida, onde decisões passadas do decisor de mínima distância são utilizadas para mitigar os efeitos da IES na detecção dos símbolos subseqüentes. Este arranjo é conhecido como equalização/filtragem com decisões realimentadas (DFE ou Decision Feedback Equalizers). Por último, os resultados obtidos com o sistema SC nas diferentes configurações de filtragem na recepção são comparados com os resultados do já estabelecido sistema OFDM. A transmissão OFDM se dá com múltiplas portadoras, onde as freqüências das sub-portadoras são ortogonais entre si, permitindo que a informação seja enviada de forma paralela. Resultados mostram que os sistemas SC-FDE tem desempenho superior aos sistemas OFDM. / [en] The demand for high rate transmission systems, for example in HDTV, third and fourth generation cellular telephony, DSL and so on, causes the rise of a problem: The multipath communications channel (specially in wireless communications), which leads to intersymbol interference phenomenon (ISI). The present work investigates the performance of single-carrier (SC) transmission systems with frequency-domain linear equalization. Different recursive algorithms are presented in order to implement these FIR filters. Besides the linear equalizers, a non- linear structure is introduced, where the past decisions made by the detectors are used to mitigate the effect of ISI on the detection of the forthcoming symbols. This set is known as Decision Feedback Equalizers (DFE). Finally, the results of the aforementioned systems are compared to the well-known OFDM. OFDM transmission relies on sub-carriers, frequency orthogonal to each other, in which the data is sent in a parallel basis. The results obtained show that SC- FDE systems outperform OFDM systems.

Main objective of this thesis was to learn about possibility of suppression of narrow band disturbances. We focused on use of Lynn’s filters. The objective was to realize these filters with respect to a fast algorithm of filtering. Concretely, for suppression of drift we realized the fast high pass filter with flexible cut off frequency. Then we realized filter for suppression of electrical network disturbance. We have realized these filters for sampling frequencies 250 and 500 Hz and we tested them with real ECG signals. Then we have evaluated their efficiency.

Objective of this diploma work was to study methods of adaptive filtering and their use in suppression of noise in biological signals. Adaptive filtering represents effective means of suppression of parasitic nonstationary disturbances in a useful signal. The task was to design various types of adaptive filters and implement an adaptation algorithm in Matlab programming environment. It namely included suppression of powerline noise at 50 Hz and 100 Hz in ECG signals with minimization useful components disturbing. The realized filters were verified on real ECH signals and their efficiency was evaluated.

The aim was to test the methods for suppression 50 Hz noise with adaptive filtering. When using the general scheme of adaptive and deterministic scheme to suppress hum. The work is a theoretical derivation of adaptive algorithms and some examples of modeling in MATLAB.

No description available.

Battery Electric Vehicles (BEV) are gaining market share but still must overcome several engineering challenges related to the lithium-ion battery packs powering them. The batteries must be carefully managed to optimize safety and performance. The estimation of battery states, which cannot be measured directly, is an important part of battery management and remains an active area of research since small gains in estimation accuracy can help reduce cost and increase BEV range. This thesis presents several improvements to battery state estimation using different methods. Electrochemical Impedance Spectroscopy (EIS) is receiving increased attention from researchers as a method for state estimation and diagnostics for real-time applications. Due to battery relaxation behaviour, long rest times are commonly used before performing the EIS measurement. In this work, methods were developed to significantly shorten the required rest times, and a State of Health (SoH) estimation strategy was proposed by taking advantage of the relaxation effect as measured by EIS. This method was demonstrated to have an estimation error of below 1%. At low temperatures, the accuracy of the battery model becomes poor due to the non-linear battery response to current. By using an adaptive filter called the Interacting Multiple Model (IMM) filter, the next part of this work showed how to significantly improve low temperature State of Charge (SoC) estimation. Further reduction in estimation errors was achieved by pairing the IMM with the Smooth Variable Structure Filter (SVSF), for SoC estimation errors below 2%. The work presented in this thesis also includes the application of Deep Neural Networks (DNN) for SoC estimation from EIS data. Finally, an extensive aging study was conducted and an accelerated protocol was compared to a realistic drive cycle based protocol using EIS as a characterization tool. / Thesis / Doctor of Philosophy (PhD) / Replacing conventional gasoline/diesel powered cars with battery powered vehicles is part of a solution to the climate crisis. However, the initial costs paired with range anxiety stops many from switching to electric cars. Both cost and range are related to the battery pack. To achieve the best possible range for the lowest possible cost, battery packs must be carefully controlled by sophisticated algorithms. Unfortunately, battery range or health cannot be measured directly, but must be inferred through measurable indicators. This thesis explores battery behavior under different operating conditions and develops improved methods which can be used to determine battery health and/or range. A powerful method usually used only in laboratory settings is studied and improved to make it more suitable for implementation in electric cars. In this work it is used for accurate battery health determination. Furthermore, a strategy for improving battery range determination at low temperatures is also proposed.