Fixed-analysis adaptive-synthesis filter banks

Subband/Wavelet filter analysis-synthesis filters are a major component in many compression algorithms. Such compression algorithms have been applied to images, voice, and video. These algorithms have achieved high performance. Typically, the configuration for such compression algorithms involves a bank of analysis filters whose coefficients have been designed in advance to enable high quality reconstruction. The analysis system is then followed by subband quantization and decoding on the synthesis side. Decoding is performed using a corresponding set of synthesis filters and the subbands are merged together. For many years, there has been interest in improving the analysis-synthesis filters in order to achieve better coding quality. Adaptive filter banks have been explored by a number of authors where by the analysis filters and synthesis filters coefficients are changed dynamically in response to the input. A degree of performance improvement has been reported but this approach does require that the analysis system dynamically maintain synchronization with the synthesis system in order to perform reconstruction. In this thesis, we explore a variant of the adaptive filter bank idea. We will refer to this approach as fixed-analysis adaptive-synthesis filter banks. Unlike the adaptive filter banks proposed previously, there is no analysis synthesis synchronization issue involved. This implies less coder complexity and more coder flexibility. Such an approach can be compatible with existing subband wavelet encoders. The design methodology and a performance analysis are presented.Ph.D.Committee Chair: Smith, Mark J. T.; Committee Co-Chair: Mersereau, Russell M.; Committee Member: Anderson, David; Committee Member: Lanterman, Aaron; Committee Member: Rosen, Gail; Committee Member: Wardi, Yora

Spread spectrum communication link using surface wave devices

A fast lock-up, 8-MHz bandwidth 8,000 bit per second data rate spread spectrum communication link breadboard is described that is implemented using surface wave devices as the primary signal generators and signal processing elements. It uses surface wave tapped delay lines in the transmitter to generate the signals and in the receiver to detect them. The breadboard provides a measured processing gain for Gaussian noise of 31.5 dB which is within one dB of the theoretical optimum. This development demonstrates that spread spectrum receivers implemented with surface wave devices have sensitivities and complexities comparable to those of serial correlation receivers, but synchronization search times which are two to three orders of magnitude smaller

Deep learning for automated sleep monitoring

Wearable electroencephalography (EEG) is a technology that is revolutionising the longitudinal monitoring of neurological and mental disorders, improving the quality of life of patients and accelerating the relevant research. As sleep disorders and other conditions related to sleep quality affect a large part of the population, monitoring sleep at home, over extended periods of time could have significant impact on the quality of life of people who suffer from these conditions. Annotating the sleep architecture of patients, known as sleep stage scoring, is an expensive and time-consuming process that cannot scale to a large number of people. Using wearable EEG and automating sleep stage scoring is a potential solution to this problem. In this thesis, we propose and evaluate two deep learning algorithms for automated sleep stage scoring using a single channel of EEG. In our first method, we use time-frequency analysis for extracting features that closely follow the guidelines that human experts follow, combined with an ensemble of stacked sparse autoencoders as our classification algorithm. In our second method, we propose a convolutional neural network (CNN) architecture for automatically learning filters that are specific to the problem of sleep stage scoring. We achieved state-of-the-art results (mean F1-score 84%; range 82-86%) with our first method and comparably good results with the second (mean F1-score 81%; range 79-83%). Both our methods effectively account for the skewed performance that is usually found in the literature due to sleep stage duration imbalance. We propose a filter analysis and visualisation methodology for CNNs to understand the filters that CNNs learn. Our results indicate that our CNN was able to robustly learn filters that closely follow the sleep scoring guidelines.Open Acces

The Kinematics of the Sagittarius Stream.

Tidal streams can provide us with a great deal of information about their dwarf progenitors, and by implication, the progenitors of the building blocks of stellar halos, such as: their stellar populations, their mass and mass loss rate, and their orbital history and future. But, perhaps more importantly, streams can help us probe properties of their host galaxy. Since the locations, and motions of the stars that comprise a stream reflect the underlying gravitational potential in which they orbit, their positions and kinematics can be used to determine, or at least place constraints upon, the distribution of matter in the halo. In particular, the size and shape of the dark matter halo can be constrained. There have been numerous efforts to use observations of the Sgr streams to constrain the shape of the Milky Way's dark matter halo. Sgr is the only known Milky Way satellite with substantial streams encircling more than 360 degrees around its host, making it the perfect candidate for such a study. However, various models, relying upon the contemporaneously available observations of Sgr, have produced strikingly contradictory results, initiating a seemingly intractable debate over the shape of the Milky Way's dark matter halo. The data has been interpreted in favor of halos of all possible shapes: spherical, oblate, prolate, triaxial, and transitional. We present the results of an extensive observational undertaking to acquire the single largest spectroscopic data set of Sgr stream stars. Using a combination of telescopes and instruments in both hemispheres we have completed a kinematic survey including velocity measurements for 2368 unique main-sequence stars in 39 fields spanning the full 360 degrees along the Sgr streams. The results of this kinematic survey are compared to the predictions of $N$-body models of the destruction of Sgr in Galactic halos of various shapes. We find that the observed radial velocity trends along the streams are best reproduced by the triaxial halo model. Amongst the axisymmetric models, the prolate halo provides the best match to the observations, while the spherical and oblate models can be ruled out.PHDAstronomy and AstrophysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/108726/1/tbrink_1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108726/2/tbrink_3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108726/3/tbrink_2.pd

Nove klase funkcija za sintezu dvokanalne hibridne banke filtara

This PhD discusses the research related to the approximation and implementation of the twochannel hybrid filter banks. Special attention is paid to the analogue part, i.e. analysis part of the hybrid filter banks. Two approximations of the filter bank pair for analysis have been proposed. The first approximation of the transfer function of the low-pass filter is based on the simple adaptation of the orthogonal Jacobi polynomials in order to obtain the Pseudo-Jacobian polynomials. In relation to other known approximations, the Pseudo-Jacobian polynomial one has two prime parameters, which can adjust the characteristics of the filter in wide ranges. This approximation can be successfully applied for the realization of a complementary bank of filters. It is known that recursive double-complementary digital filter banks can be implemented with all-pass filters, and research has shown that double-complementary filter banks can also be realized in the analogue domain. The realization of the proposed filter bank has been done in two steps. In the first step, with the complementary decomposition, the prototype transfer function is obtained by two all-pass filters, while in the second step, by their addition or subtraction, transfer functions of lowpass and highpass filters are obtained. The advantage of such a system is that the same hardware can be used for realization of both low frequency and high frequency transfer functions. Monte Carlo simulation of the realization of a double complementary analog filter pair based on a parallel connection of two analogue all-pass filters showed that all-pass realization is characterized by a small sensitivity of the attenuation characteristics to the component tolerances in the filter pass-band, while the sensitivity in the stop-band is substantially higher compared to the case of a standard cascade realization of the low-pass filter and the high-pass filter. By a suitable selection of the analysis filter bank and the synthesis filter bank, a condition for suppressing the effects arising from the overlapping of the spectrum in banks for analysis and synthesis can be fulfilled. The all-pass complementarity of an analogue filter bank points to the fact that amplitude distortion, which is introduced by the analog bank of the analysis filters, can be completely suppressed, so that the non-linearity of the group delay characteristics is the predominant distortion. In order to achieve a near perfect reconstruction of the signal, a new realization of the group delay corrector was proposed, which makes it possible for the group delay to be constant in a flat sense, i.e. with a number of flatness at the origin. An analysis of the sensitivity has shown that the sensitivity of the correction of the group waveform in the filter pass-band that is proportional to the square of the Q -factor of the pole. In other words, the group delay corrector is very sensitive to the component tolerances

Enabling Optical Wired and Wireless Technologies for 5G and Beyond Networks

The emerging fifth-generation mobile communications are envisaged to support massive number of deployment scenarios based on the respective use case requirements. The requirements can be efficiently attended with ultradense small-cell cloud radio access network (C-RAN) approach. However, the C-RAN architecture imposes stringent requirements on the transport networks. This book chapter presents high-capacity and low-latency optical wired and wireless networking solutions that are capable of attending to the network demands. Meanwhile, with optical communication evolutions, there has been advent of enhanced photonic integrated circuits (PICs). The PICs are capable of offering advantages such as low-power consumption, high-mechanical stability, low footprint, small dimension, enhanced functionalities, and ease of complex system architectures. Consequently, we exploit the PICs capabilities in designing and developing the physical layer architecture of the second standard of the next-generation passive optical network (NG-PON2) system. Apart from being capable of alleviating the associated losses of the transceiver, the proposed architectures aid in increasing the system power budget. Moreover, its implementation can significantly help in reducing the optical-electrical-optical conversions issue and the required number of optical connections, which are part of the main problems being faced in the miniaturization of network elements. Additionally, we present simulation results for the model validation

Measurements, Models, Systems and Design

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THE NOVEL DESMOSOMAL PROTEIN POF1B IS ESSENTIAL FOR CELL-CELL ADHESION STRENGTH

POF1B is a candidate gene for premature ovarian failure (POF); it is mainly expressed in polarized epithelial tissues, but its function in these tissues and the relationship with the disorder are unknown. In polarized epithelial MDCK cells the human stably expressed POF1B showed a tight junction localization that was lost by the POF1B R329Q variant associated with POF. Although the apico-basal polarity markers and ultrastructure of the tight junctions were maintained in cells expressing the mutant, tight junction assembly, as well as the organization of the monolayer appeared altered. Moreover, cells expressing the POF1B R329Q variant showed defects in ciliogenesis and cystogenesis as a result of misorientation of primary cilia and mitotic division. All of these defects were explained by interference of the mutant with the content and organization of F-actin at the junctions. Subsequently, by means of morphological and biochemical criteria we documented that POF1B is actually a desmosome- associated protein. Both in Caco-2 human intestinal cells and in stratified HaCaT keratinocyte cell lines, indeed, endogenous POF1B colocalized with desmoplakin and plakophilin 2 at the desmosomal plaque and in cytoplasmic particles aligned along intermediate filaments. POF1B co-fractionated with desmosomes and intermediate filament components and showed properties characteristic of desmosomes (i.e. detergent insolubility and calcium independence). Furthermore, POF1B was required for desmosome assembly and function, as the stable downregulation of the protein in HaCaT cells caused a decrease in desmosome number and size, and these desmosomes had very weak electron dense plaques. Among the cell-cell adhesion structures, desmosomes are the most essential for mechanical coupling. The reduced capability of POF1B-silenced keratinocytes to respond to mechanical stress revealed the protein's crucial role in these junctions. Moreover, altered desmosomes in POF1B- downregulated keratinocytes were associated with altered cell proliferation and differentiation. The localization of POF1B in simple and stratified epithelia, as well as its relocation to desmosomes in human skin tumors, further indicated the protein's role in desmosome function, and suggested its involvement in human diseases associated with impairment of these junctions