Dissertations / Theses on the topic 'Signal detection'
To see the other types of publications on this topic, follow the link: Signal detection.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Signal detection.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Park, Subok. "Signal detection with random backgrounds and random signals." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280729.
Full textAbstract:
In this dissertation we explore theoretical and computational methods to investigate Bayesian ideal observers for performing signal-detection tasks. Object models are used to take into account object variability in image backgrounds and signals for the detection tasks. In particular, lumpy backgrounds (LBs) and Gaussian signals are used for various paradigms of signal-detection tasks. Simplified pinhole imaging systems in nuclear medicine are simulated for this work. Markov-chain Monte Carlo (MCMC) methods that estimate the ideal observer test statistic, the likelihood ratio, for signal-known-exactly (SKE) tasks, where signals are nonrandom, are employed. MCMC methods are extended to signal-known-statistically (SKS) tasks, where signals are random. Psychophysical studies for the SKE and SKS tasks using non-Gaussian and Gaussian distributed LBs are conducted. The performance of the Bayesian ideal observer, the human observer, and the channelized-Hotelling observer for the SKE and SKS tasks is compared. Human efficiencies for both the SKE tasks and SKS tasks are estimated. Also human efficiencies for non-Gaussian and Gaussian-distributed LBs are compared for the SKE tasks. Finally, the theory of the channelized-ideal observer (CIO) is introduced to approximate the performance of the ideal observer by the performance of the CIO in cases where the channel outputs of backgrounds and signals are non-Gaussian distributed. Computational approaches to estimate the CIO are investigated.
2
Lie, Celia, and n/a. "Punishment and human signal detection." University of Otago. Department of Psychology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20071004.134135.
Full textAbstract:
Detection and choice research have largely focused on the effects of relative reinforcer frequencies or magnitudes. The effects of punishment have received much less attention. This thesis investigated the effects of punishment on human signal-detection performance using a number of different procedures. These included punisher frequency and magnitude variations, different types of punishers (point loss & time-outs), variations in stimulus disparity, and different detection tasks (judgments of stimulus arrays containing either more blue or red objects, or judgments of statements that were either true or false). It examined whether punishers have similar, but opposite, effects to reinforcers on detection performance, and whether the effects of punishment were successfully captured by existing models of punishment and choice.
Experiment 1 varied the relative frequency or magnitude of time-out punishers for errors using the blue/red task. Participants were systematically biased away from the response alternative associated with the higher rate or magnitude of time-out punishers in two of three procedures. Experiment 2 varied the relative frequency of point-loss punishers using the blue/red task and the true/false task. Participants were systematically biased away from the alternative associated with the higher rate of point-loss punishers for the true/false task.
Experiment 3 examined the effects of punishment on response bias from a psychophysical perspective. Previous detection research which varied stimulus discriminability while holding reinforcers ratios constant and unequal (Johnstone & Alsop, 2000; McCarthy & Davison, 1984) found that a criterion location measure (e.g., c, Green & Swets, 1966) was a better descriptor of isobias functions compared to a likelihood ratio measure (e.g., log β[G], Green & Swets, 1966). Experiment 3 varied stimulus discriminability while holding punisher ratios constant and unequal. Like previous research, isobias functions were consistent with a criterion location measure.
Experiments 4, 5, 6, and 7 examined contemporary models of choice and punishment. Experiments 4, 5, and 6 varied the relative reinforcer ratio in detection tasks, both with and without the inclusion of an equal rate of punishment. Experiment 7 held the reinforcer ratio constant and unequal, and varied the durations of time-out punishers. Increases in preference (for the richer alternative) from reinforcer-only conditions to reinforcer + punisher conditions would support a subtractive model of punishment, while decreases in preference would support an additive model of punishment.
Experiment 4 was a between-groups study using time-out punishers. It supported the predictions of an additive model. Experiment 5 used three different procedures in a preliminary within-subjects design, evaluating which procedure was best suited for a larger within-subjects experiment (Experiment 6). In Experiment 6, participants sat four reinforcer-only and four reinforcer + punisher conditions where reinforcers were point-gains and punishers were point-losses. The results from Experiment 6 were mixed - some participants showed increased preference while others showed little change or a slight decrease. This appeared related to the order in which participants received the reinforcer-only and reinforcer + punisher conditions. Experiment 7 also found no consistent change in preference with increases in time-out durations. Instead, there was a slow increase in bias on the richer alternative across the eight sessions.
Overall, punishers had similar, but opposite, effects to reinforcers in detection procedures (Experiments 1, 2, & 3). These effects were successfully captured by Davison and Tustin�s (1978) model of detection. The later experiments did not provide support for a subtractive model punishment model of choice, which had provided the best descriptor in corresponding concurrent-schedule research. Instead, Experiment 4 supported an additive model, and Experiments 5, 6, and 7 provided no evidence for either model - limitations and implications of these studies are discussed. However, the present thesis illustrates that the signal detection procedure is promising for studying the combined effects of reinforcement and punishment, and may offer a worthwhile complement to standard concurrent-schedule choice procedures.
3
Huang, Wensheng. "Wavelet Transform Adaptive Signal Detection." NCSU, 1999. http://www.lib.ncsu.edu/theses/available/etd-19991104-151423.
Full textAbstract:
Wavelet Transform Adaptive Signal Detection is a signal detection method that uses the Wavelet Transform Adaptive Filter (WTAF). The WTAF is the application of adaptive filtering on the subband signals obtained by wavelet decomposition and reconstruction. The WTAF is an adaptive filtering technique that leads to good convergence and low computational complexity. It can effectively adapt to non-stationary signals, and thus could find practical use for transient signals. Different architectures for implementing the WTAF were proposed and studied in this dissertation. In terms of the type of the wavelet transform being used, we presented the DWT based WTAF and the wavelet tree based WTAF. In terms of the position of the adaptive filter in the signal paths of the system, we presented the Before-Reconstruction WTAF, in which the adaptive filter is placed before the reconstruction filter; and the After-Reconstruction WTAF, in which the adaptive filter is placed after the reconstruction filter. This could also be considered as implementing the adaptive filtering in different domains, with the Before-Reconstruction structure corresponding to adaptive filtering in the scale-domain, and the After-Reconstruction structure corresponding to adaptive filtering in the time-domain. In terms of the type of the error signal used in the WTAF, we presented the output error based WTAF and the subband error based WTAF. In the output error based WTAF, the output error signal is used as input to the LMS algorithm. In the subband error based WTAF, the error signal in each subband is used as input to the LMS algorithm. The algorithms for the WTAF were also generalized in this work. In order to speed up the calculation, we developed the block LMS based WTAF, which modifies the weights of the adaptive filter block-by-block instead of sample-by-sample. Experimental studies were performed to study the performance of different implementation schemes for the WTAF. Simulations were performed on different WTAF algorithms with a sinusoidal input and with a pulse input. The speed and stability properties of each structure were studied experimentally and theoretically. It was found that different WTAF structures had different tradeoffs in terms of stability, performance, computational complexity, and convergence speed. The WTAF algorithms were applied to an online measurement system for fabric compressional behavior and they showed encouraging results. A 3-stage DWT based WTAF and a block WTAF based on a 3-stage DWT was employed to process the noisy force-displacement signal acquired from the online measurement system. The signal-to-noise ratio was greatly increased by applying these WTAFs, which makes a lower sampling rate a possibility. The reduction of the required time for data sampling and processing greatly improves the system speed to meet faster testing requirements. The WTAF algorithm could also be used in other applications requiring fast processing, such as in the real-time applications in communications, measurement, and control.
4
Krause, Michael. "Signal Detection for Overloaded Receivers." Thesis, University of Canterbury. Department of Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/2959.
Full textAbstract:
In this work wireless communication systems with multiple co-channel signals present at the receiver are considered. One of the major challenges in the development of such systems is the computational complexity required for the detection of the transmitted signals. This thesis addresses this problem and develops reduced complexity algorithms for the detection of multiple co-channel signals in receivers with multiple antennas. The signals are transmitted from either a single user employing multiple transmit antennas, from multiple users or in the most general case by a mixture of the two. The receiver is assumed to be overloaded in that the number of transmitted signals exceeds the number of receive antennas. Joint Maximum Likelihood (JML) is the optimum detection algorithm which has exponential complexity in the number of signals. As a result, detection of the signals of interest at the receiver is challenging and infeasible in most practical systems.
The thesis presents a framework for the detection of multiple co-channel signals in overloaded receivers. It proposes receiver structures and two list-based signal detection algorithms that allow for complexity reduction compared to the optimum detector while being able to maintain near optimum performance. Complexity savings are achieved by first employing a linear preprocessor at the receiver to reduce the effect of Co-Channel Interference (CCI) and second, by using a detection algorithm that searches only over a subspace of the transmitted symbols. Both algorithms use iterative processing to extract ordered lists of the most likely transmit symbols. Soft information can be obtained from the detector output list and can then be used by error control decoders.
The first algorithm named Parallel Detection with Interference Estimation (PD-IE) considers the Additive White Gaussian Noise (AWGN) channel. It relies on a spatially reduced search over subsets of the transmitted symbols in combination with CCI estimation. Computational complexity under overload is lower than that of JML. Performance results show that PD-IE achieves near optimum performance in receivers with Uniform Circular Array (UCA) and Uniform Linear Array (ULA) antenna geometries.
The second algorithm is referred to as List Group Search (LGS) detection. It is applied to overloaded receivers that operate in frequency-flat multipath fading channels. The List Group Search (LGS) detection algorithm forms multiple groups of the transmitted symbols over which an exhaustive search is performed. Simulation results show that LGS detection provides good complexity-performance tradeoffs under overload.
A union bound for group-wise and list-based group-wise symbol detectors is also derived. It provides an approximation to the error performance of such detectors without the need for simulation. Moreover, the bound can be used to determine some detection parameters and tradeoffs. Results show that the bound is tight in the high Signal to Interference and Noise Ratio (SINR) region.
5
Arslanian, A. S. "Spectral techniques for signal detection." Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372465.
Full text
6
Shikhaliev, Azer P. "Techniques for Adaptive Signal Detection." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1610123085674943.
Full text
7
Gallas, Brandon Dominic. "Signal detection in lumpy backgrounds." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290090.
Full textAbstract:
In this dissertation we explore signal detection with model and human observers in the setting of nuclear medicine. Regarding the model observer, the main focus is on the linear observer that maximizes detectability, which we call the Hotelling observer. In particular, we outline two methods for realizing an estimate of this observer. The first uses a Fourier representation. The second uses a representation with a small number of channels chosen for optimal performance. The work employs statistically defined lumpy backgrounds to test the methods and results. These backgrounds are more complicated than correlated Gaussian noise and are meant to complicate the signal-detection task by involving random structure. Regarding the human observer, we present a literature review of psychophysical models, including results based on these models. We then examine one current front runner--a channelized-Hotelling observer with channels modeling visual-response functions---for two experiments involving the lumpy backgrounds.
8
Zhang, Hongbin. "Signal detection in medical imaging." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290512.
Full textAbstract:
The goal of this research is to develop computational methods for predicting how a given medical imaging system and reconstruction algorithm will perform when mathematical observers for tumor detection use the resulting images. Here the mathematical observer is the ideal observer, which sets an upper limit to the performance as measured by the Bayesian risk or receiver operating characteristic analysis. This dissertation concentrates on constructing the ideal observer in complex detection problems and estimating its performance. Thus the methods reported in this dissertation can be used to approximate the ideal observer in real medical images. We define our detection problem as a two-hypothesis detection task where a known signal is superimposed on a random background with complicated distributions and embedded in independent Poisson noise. The first challenge of this detection problem is that the distribution of the random background is usually unknown and difficult to estimate. The second challenge is that the calculation of the ideal observer is computationally intensive for non stylized problems. In order to solve these two problems, our work relies on multiresolution analysis of images. The multiresolution analysis is achieved by decomposing an image into a set of spatial frequency bandpass images so each bandpass image represents information about a particular fitness of detail or scale. Connected with this method, we will use three types of image representation by invertible linear transforms. They are the orthogonal wavelet transform, pyramid transform and independent component analysis. Based on the findings from human and mammalian vision, we can model textures by using marginal densities of a set of spatial frequency bandpass images. In order to estimate the distribution of an ensemble of images given the empirical marginal distributions of filter responses, we can use the maximum entropy principle and get a unique solution. We find that the ideal observer calculates a posterior mean of the ratio of conditional density functions, or the posterior mean of the ratio of two prior density functions, both of which are high dimensional integrals and have no analytic solution usually. But there are two ways to approximate the ideal observer. The first one is a classic decision process; that is, we construct a classifier following feature extraction steps. We use the integrand of the posterior mean as features, which are calculated at the estimated background close to the posterior mode. The classifier combines these features to approximate the integral (or the ideal observer). Finally, if we know both the conditional density function and the prior density function then we can also approximate the high dimensional integral by Monte Carlo integration methods. Since the calculation of the posterior mean is usually a very high dimensional integration problem, we must construct a Markov chain, which can explore the posterior distribution efficiently. We will give two proposal functions. The first proposal function is the likelihood function of random backgrounds. The second method makes use of the multiresolution representation of the image by decomposing the image into a set of spatial frequency bands. Sampling one pixel in each band equivalently updates a cluster of pixels in the neighborhood of the pixel location in the original image.
9
Mabrouk, Mohamed Hussein Emam Mabrouk. "Signal Processing of UWB Radar Signals for Human Detection Behind Walls." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/31945.
Full textAbstract:
Non-contact life detection is a significant component of both civilian and military rescue applications. As a consequence, this interest has resulted in a very active area of research. The primary goal of this research is reliable detection of a human breathing signal. Additional goals of this research are to carry out detection under realistic conditions, to distinguish between two targets, to determine human breathing rate and estimate the posture. Range gating and Singular Value Decomposition (SVD) have been used to remove clutter in order to detect human breathing under realistic conditions. However, the information of the target range or what principal component contains target information may be unknown. DFT and Short Time Fourier Transform (STFT) algorithms have been used to detect the human breathing and discriminate between two targets. However, the algorithms result in many false alarms because they detect breathing when no target exists. The unsatisfactory performance of the DFT-based estimators in human breathing rate estimation is due to the fact that the second harmonic of the breathing signal has higher magnitude than the first harmonic. Human posture estimation has been performed by measuring the distance of the chest displacements from the ground. This requires multiple UWB receivers and a more complex system. In this thesis, monostatic UWB radar is used. Initially, the SVD method was combined with the skewness test to detect targets, discriminate between two targets, and reduce false alarms. Then, a novel human breathing rate estimation algorithm was proposed using zero-crossing method. Subsequently, a novel method was proposed to distinguish between human postures based on the ratios between different human breathing frequency harmonics magnitudes. It was noted that the ratios depend on the abdomen displacements and higher harmonic ratios were observed when the human target was sitting or standing. The theoretical analysis shows that the distribution of the skewness values of the correlator output of the target and the clutter signals in a single range-bin do not overlap. The experimental results on human breathing detection, breathing rate, and human posture estimation show that the proposed methods improve performance in human breathing detection and rate estimation.
10
Pike, Cameron M. "Multipath signal detection using the bispectrum." Ohio : Ohio University, 1990. http://www.ohiolink.edu/etd/view.cgi?ohiou1183467926.
Full text
11
Hoppe, Elizabeth A. "Improving Signal Clarity through Interference Suppression and Emergent Signal Detection." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/39325.
Full textAbstract:
Microphone arrays have seen wide usage in a variety of fields; especially in sonar, acoustic source monitoring and localization, telecommunications, and diagnostic medicine.
The goal of most of these applications is to detect or extract a signal of interest. This task is complicated by the presence of interferers and noise, which corrupts the recorded array signals. This dissertation explores two new techniques that increase signal clarity: interferer suppression and emergent signal detection.
Spatial processing is often used to suppress interferers that are spatially distinct from the signal of interest. If the signal of interest and the interferer are statistically independent, blind source separation can be used to statistically extract the signal of interest. The first new method to improve signal clarity presented in this work combines spatial processing with blind source separation to suppress interferers. This technique allows for the separation of independent sources that are not necessarily simultaneously mixed or spatially distinct. Simulations and experiments are used to show the capability of the new algorithm for a variety of conditions. The major contributions in this dissertation under this topic are to use independent component analysis to extract the signal of interest from a set of array signals, and to improve existing independent component analysis algorithms to allow for time delayed mixing.
This dissertation presents a novel method of improving signal clarity through emergent signal detection. By determining which time frames contain the signal of interest, frames that contain only interferers and noise can be eliminated. When a new signal of interest emerges in a measurement of a mixed set of sources, the principal component subspace is altered. By examining the change in the subspace, the emergent signal can be robustly detected. This technique is highly effective for signals that have a near constant sample variance, but is successful at detecting a wide variety of signals, including voice signals. To improve performance, the algorithm uses a feed-forward processing technique. This is helpful for the VAD application because voice does not have a constant sample variance. Experiments and simulations are used to demonstrate the performance of the new technique.Ph. D.
12
Li, Tao. "Signal detection in unknown interference channels /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?ECED%202006%20LI.
Full text
13
Lehtomäki, J. (Janne). "Analysis of energy based signal detection." Doctoral thesis, University of Oulu, 2005. http://urn.fi/urn:isbn:9514279255.
Full textAbstract:
Abstract
The focus of this thesis is on the binary signal detection problem, i.e., if a signal or signals are present or not. Depending on the application, the signal to be detected can be either unknown or known. The detection is based on some function of the received samples which is compared to a threshold. If the threshold is exceeded, it is decided that signal(s) is (are) present. Energy detectors (radiometers) are often used due to their simplicity and good performance. The main goal here is to develop and analyze energy based detectors as well as power-law based detectors.
Different possibilities for setting the detection threshold for a quantized total power radiometer are analyzed. The main emphasis is on methods that use reference samples. In particular, the cell-averaging (CA) constant false alarm rate (CFAR) threshold setting method is analyzed. Numerical examples show that the CA strategy offers the desired false alarm probability, whereas a more conventional strategy gives too high values, especially with a small number of reference samples.
New performance analysis of a frequency sweeping channelized radiometer is presented. The total power radiometer outputs from different frequencies are combined using logical-OR, sum and maximum operations. An efficient method is presented for accurately calculating the likelihood ratio used in the optimal detection. Also the effects of fading are analyzed. Numerical results show that although sweeping increases probability of intercept (POI), the final probability of detection is not increased if the number of observed hops is large.
The performance of a channelized radiometer is studied when different CFAR strategies are used to set the detection threshold. The proposed iterative methods for setting the detection threshold are the forward consecutive mean excision (FCME) method with the CA scaling factors in final detection decision (FCME+CA), the backward consecutive mean excision (BCME) method with the CA scaling factors in detection (BCME+CA) and a method that uses the CA scaling factors for both censoring and detection (CA+CA). Numerical results show that iterative CFAR methods may improve detection performance compared to baseline methods.
Finally, a method to set the threshold of a power-law detector that uses a nonorthogonal transform is presented. The mean, variance and skewness of the decision variable in the noise-only case are derived and these are used to find a shifted log-normal approximation for the distribution of the decision variable. The accuracy of this method is verified through simulations.
14
Chen, Hao. "Noise enhanced signal detection and estimation." Related electronic resource:, 2007. http://proquest.umi.com/pqdweb?did=1342743841&sid=2&Fmt=2&clientId=3739&RQT=309&VName=PQD.
Full text
15
Adams, Mark D. "Signal detection optimization for underwater acoustics." Master's thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-02022010-020009/.
Full text
16
ORTEGA, ALVARO JAVIER. "SIGNAL DETECTION IN MASSIVE MIMO SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=26176@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
Este trabalho de dissertação de mestrado apresenta uma comparação de algumas das técnicas de detecção de sinais mais promissoras para a viabilização de sistemas MIMO de grande porte em termos de desempenho, taxa de erro de bit e complexidade, número médio de flops requeridos por vetor de símbolos recebido. Com este objetivo foram também consideradas as técnicas de detecção clássicas, visando assim ressaltar o desempenho das novas técnicas com relação as antigas. Além disso foram propostas e investigadas novas estruturas para detectores SIC baseados em lista (i.e., com múltiplos ramos) que resultaram em melhor desempenho com menor complexidade quando comparados aos detectores deste tipo já propostos. Na comparação dos algoritmos, foram considerados três cenários diferentes: (i ) monousuário, com ganhos de canal gaussianos complexos independentes e identicamente distribuídos, ou seja, uma propagação que só considera a presença de desvanecimento de Rayleigh; (ii ) múltiplos usuários com canais correlatados e que considera as perdas de propagação de pequena e larga escala num sistema com antena centralizada; e (iii ) múltiplos usuários com canais correlatados e que considera as perdas de propagação de pequena e larga escala num sistema com antena distribuída.
This work dissertation presents a comparison of some of the signal detection techniques most promising for the viability of large MIMO systems in terms of performance, bit error rate, and complexity, average number of flops required by transmitted symbol vector. For this purpose it was also considered classical detection techniques, thus aiming to highlight the performance of new techniques with respect the old. Also it has been proposed and investigated new structures to SIC detectors based on list (i.e., with multiple branches) resulting in better performance with less complexity compared to detectors of this kind already proposed. In the comparison of algorithms, three different scenarios were used: (i ) single user, with channel gains independent and distributed identically complex Gaussian, that is, a spread that only considers the presence of Rayleigh fading; (ii ) multiple users, with correlated channels, and considers the short and large scale path loss in a system with centralized antenna; e (iii ) multiple users, with correlated channels, and considers the short and large scale path loss in a system with distributed antenna.
17
Crane, Nicola. "Debiasing reasoning : a signal detection analysis." Thesis, Lancaster University, 2016. http://eprints.lancs.ac.uk/82265/.
Full textAbstract:
This thesis focuses on deductive reasoning and how the belief bias effect can be reduced or ameliorated. Belief bias is a phenomenon whereby the evaluation of the logical validity of an argument is skewed by the degree to which the reasoner believes the conclusion. There has been little research examining ways of reducing such bias and whether there is some sort of effective intervention which makes people reason more on the basis of logic. Traditional analyses of this data has focussed on simple measures of accuracy, typically deducting the number of incorrect answers from the number of correct answers to give an accuracy score. However, recent theoretical developments have shown that this approach fails to separate reasoning biases and response biases. A reasoning bias, is one which affects individuals’ ability to discriminate between valid and invalid arguments, whereas a response bias is simply the individual’s tendency to give a particular answer, independent of reasoning. A Signal Detection Theory (SDT) approach is used to calculate measures of reasoning accuracy and response bias. These measures are then analysed using mixed effects models. Chapter 1 gives a general introduction to the topic, and outlines the content of subsequent chapters. In Chapter 2, I review the psychological literature around belief bias, the growth of the use of SDT models, and approaches to reducing bias. Chapter 3 covers the methodology, and includes a a thorough description of the calculation of the SDT measures, and an explanation of the mixed effects models I used to analyse these. Chapter 4 presents an experiment in which the effects of feedback on reducing belief bias is examined. In Chapter 5, the focus shifts in the direction of individual differences, and looks at the effect of different instructions given to participants, and Chapter 6 examines the effects of both feedback and specific training. Chapter 7 provides a general discussion of the implications of the previous three chapters.
18
Sexton, G. "Ground probing radar signal processing techniques." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354404.
Full text
19
Qu, Yang. "Mixed Signal Detection, Estimation, and Modulation Classification." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1576615989584971.
Full text
20
Icaza, Astiz Yannik Alan de. "Optimal signal recovery for pulsed balanced detection." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/285635.
Full textAbstract:
To measure quantum features in a classical world constrains us to extend the classical technology to the limit, inventing and discovering new schemes to use the classical devices, while reducing and filtering the sources of noise. Balanced detectors, e.g. when measuring a low- noise laser, have become an exceptional tool to attain the shot-noise level, i.e., the standard quantum limit for measuring light. To detect light pulses at this level requires to decreasing and also to filtering all other sources of noise, namely electronic and technical noise.
The aim of this work is to provide a new tool for filtering technical and electronic noises present in the pulses of light. It is especially relevant for signal processing methods in quantum optics experiments, as a means to achieve shot-noise level and reduce strong technical noise by means of a pattern function. We thus present the theoretical model for the pattern-function filtering, starting with a theoretical model of a balanced detector. Next, we indicate how to recover the signal from the output of the balanced detector and a noise model is proposed for the sources of noise and the conditions that should satisfy the filtering algorithm. Finally, the problem is solved and the pattern function is obtained, the one which solves the problem of filtering technical and electronic noises.
Once the pattern function is obtained, we design an experimental setup to test and demonstrate this model-based technique. To accomplish this, we produce pulses of light using acousto-optics modulators, such light pulses are precisely characterized together with the detection system. The data are then analyzed using an oscilloscope which gathers all data in the time domain. The frequency-domain representation is calculated using mathematical functions. In this way, it is proved that our detector is shot-noise limited for continuous-wave light. Next, it is shown how the technical noise is produced in a controlled manner, and how to gather the necessary information for calculating the pattern function. Finally, the shot-noise-limited detection with pulses without technical noise introduced is shown first, and next, an experimental demonstration where 10 dB of technical noise is then filtered using the pattern function.
The final part of this research is focused on the optimal signal recovery for pulsed polarimetry. We recall the Stokes parameters and how to estimate the polarization state from a signal. Next, we introduce a widely used signal processing technique, the Wiener filter. For the final step, we show how to retrieve, under the best conditions, the polarization-rotation angle with a signal that has 10 dB of technical noise. Obtaining that our technique outperforms the Wiener estimator and at the same time obtaining the standard quantum limit for phase/angle estimation. Because of the correlation between pulsed polarimetry and magnetic estimation using magnetic-atomic ensembles via Faraday effect, this pattern-function filtering technique can be readily used for probing magnetic-atomic ensembles in environments with strong technical noise.Medir las características cuánticas en un mundo clásico no solo requiere llevar al límite la tecnología clásica, sino también, inventar y descubrir nuevos esquemas para utilizar los dispositivos clásicos, reduciendo y filtrando las fuentes de ruido. Los detectores balanceados, cuando miden un láser de bajo ruido, se han convertido en una herramienta excepcional para alcanzar el nivel del ruido de disparo, que es el límite estándar clásico para medir la luz. Detectar pulsos de luz al nivel de ruido de disparo requiere reducir y filtrar todas las otras fuentes de ruido, es decir, el ruido electrónico y el técnico. El objetivo de este trabajo es crear una nueva herramienta para filtrar ruido tanto técnico como electrónico de pulsos de luz, que es especialmente relevante para los métodos de procesamiento de señales en los experimentos de óptica cuántica, como una manera de alcanzar el nivel de ruido de disparo y reducir fuertemente el ruido técnico por medio una función patrón. Presentamos, por lo tanto, el modelo teórico para el filtrado por una función patrón. Primeramente damos el modelo teórico de un detector balanceado, luego exponemos cómo se recupera la señal de la salida del detector balanceado. A continuación proponemos un modelo para las fuentes de ruido y las condiciones que debe satisfacer el algoritmo de filtrado. Finalmente, se resuelve el problema y se obtiene la función patrón que nos permite filtrar los ruidos técnico y electrónico. Una vez que la función patrón se puede calcular, diseñamos un montaje experimental para probar y demostrar esta técnica basada en un modelo. Para tal propósito, producimos pulsos de luz usando moduladores acusto-ópticos que producen pulsos de luz que están precisamente caracterizados, junto con el sistema de detección. Los datos se analizan a continuación con un osciloscopio, reuniendo todos los datos en el dominio del tiempo. La representación del dominio de la frecuencia se calcula utilizando funciones matemáticas. De esta manera, se prueba que nuestro detector está limitado por el ruido de disparo para luz continua. Después, se muestra cómo se produce el ruido técnico de manera controlada, y cómo se reúne la información necesaria para calcular la función patrón. Finalmente, se muestra la detección limitada por el ruido de disparo para pulsos sin ruido técnico introducido primero, y luego, se hace una demostración experimental con 10 dB de ruido técnico, que se filtra a continuación usando la función patrón. La parte final de esta investigación está enfocada a la recuperación óptima de la señal para polarimetría pulsada. Recordamos los parámetros de Stokes y cómo estimar el estado de polarización de una señal. Luego, introducimos el filtro de Wiener, que es una técnica ampliamente usada en el procesamiento de señales. Para el paso final, mostramos cómo se recupera, bajo las mejores condiciones, el ángulo de rotación de polarización con una señal que tiene 10 dB de ruido técnico. Obteniendo el límite estándar cuántico para la estimación fase/ángulo y superando así el estimador de Wiener. Debido a la correlación entre polarimetría pulsada y la estimación magnética usando conjuntos atómicos magnéticos vía el efecto de Faraday, esta técnica de filtraje de función patrón puede ser fácilmente usada para sondear conjuntos atómico-magnéticos en ambientes con fuerte ruido técnico.
21
Wooler, John Peter Fairfax. "Fibre Optic Sensors for Dynamic Signal Detection." Thesis, Durham University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486827.
Full textAbstract:
There is both commercial and practical demand to extend the applications for which fibre optic sensors are used. This thesis describes the development of fibre optic sensors and systems for security and defence applications, based on established fibre-optic hydrophone I technology. Dynamic acoustic and seismic signals have been detected with sensor arrays, and used to demonstrate the detection of targets. Achievements have been made in the development and characterisation of entirely novel designs of fibre optic accelerometers and microphones, with the demonstration of arrays of these in practical application to intruder detection and the location of distant acoustic sources. Several prototypes of both acoustic and seismic sensors have been developed. Research efforts focused on designing ,,/ . /~nd establishing the perfonnance of these sensors, then refining the strongest designs for incorporation into arrays of sensors. These arrays have been deployed in environments representative of real operational deployment situations, extending the proof of principle established in the laboratory to demonstration in the field. Specifically, six entirely novel· fibre optic microphone designs are presented, concerning both intensity and interferometric schemes, and evaluated for responsivity and suitability to the location of acoustic targets in a battlefield application. The strongest of these is identified to be a foam-backed fibre wrapped mandrel, of simple design and high responsivity, and readily multiplexed into and interrogated with an inter~rometric system. An array of such foam-backed mandrel microphones is also demonstrated in the field and shown to have very good target location capability at ranges in excess of lkm. In other work, an entirely novel design of fibre optic accelerometer is presented, and theresponse of this is characterised in detail, in terms of both responsivity and the impact of the sensor set-up condition on responsivity. A buried array of such accelerometers combined with distributed cable sensors is demonstrated in a field deployment detecting the presence of signals from an intruder in the region of the array.
22
Jordan, Pamela Ann. "Optical tweezers for signal detection and micromanipulation." Thesis, University of Glasgow, 2005. http://theses.gla.ac.uk/1728/.
Full textAbstract:
The work presented in this thesis explores new multi-disciplinary applications of optical tweezers in the physical and biological sciences. Firstly, the three dimensional trapping of partially silvered sphere in a standard TEM00 optical trap was characterised. These spheres were then coated with an azo dye such that surface-enhanced resonance Raman (SERRS) measurements could be made on a single bead whilst it was simultaneously trapped in 532 nm optical tweezers. The length of time over which the SERRS signal could be recorded was increased, from milli-seconds to minutes, by using 1064 nm optical tweezers and introducing second harmonic light, generated via a frequency doubling crystal, for the excitation of the SERRS signal. In addition to trapping single particles, a spatial light modulator (SLM) was introduced into the optical tweezers to produce holographic optical tweezers. The SLM allowed the creation and manipulation of several optical beams both simultaneously and independently of each other. Three dimensional trapping and manipulation of multiple micron-sized spheres were achieved using the SLM in the Fourier plane of the traps. This ability to trap and manipulate objects, such as fluorescent spheres and E. coli, in 3D was extended to create permanent 3D structures that were set within a polymer matrix. These objects could be created, permanently set and imaged ex-situ. A summary of conclusions and ideas for future work are included.
23
BRAZ, JOAO ALFREDO CAL. "SIGNAL DETECTION IN SPATIAL MODULATION MULTIANTENNA SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=26134@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Modulação Espacial é um método de transmissão por múltiplas antenas recentemente proposto,designado por MIMO-SIM, que associa informação à escola das antenas transmissoras. Isto possibilita a redução do número de cadeias de radiofrequência e, consequentemente, a imimplementação de sistemas de comunicação que consomem menos energia. O novo esquema de comunicação dos sistemas MIMO-SIM exige que, do lado redeptor, novas e eficientes estratégias de detecção do sinal transmitido sejam elaborados. O detector de máxima verossimilhança (ML), que fornece o desempenho ótimo, é de inviável implementação devido ao elevado custo computacional. Os detectores Sphere Decoding (SD) são comumente aplicados aos sistemas MIMO e atingem o desempenho ótimo a menor custo de computação. Um algoritmo SD que considera as caractéristicas do sinal SM foi desenvolvido, resultando em redução de custo computacional em relação ao detector ML e aos algoritmos SD convencionais. A elevada sensibilidade da complexidade dos algoritmos SD à variação da relação sinal-ruído (SNR) motivou o desenvolvimento de técnicas de detencção subótimas. Estratégias baseadas em detecção em grupos foram propostas, e os algoritmos de detecção aninhada MLA-M e MLA-C tiveram sua complexidade e desempenho avaliados em diferetes configurações e cenários de canal. Uma nova família de detectores, que realiza a detecção da combinação de antenas transmissoras e dos símbolos transmitidos em fases distintas, foi proposto, eo algoritmo List-BMP-LR-MMSE atingiu desempenho de detecção quase ótimo com baixo custo computacional, menos sensível à variação de SNR. Baseado na estratégia de detecção em duas fases, um novo detector de baixo custo foi desenvolvido para sistemas SM com codificação espácio-temporal.
Spatial Modulation is a recently proposed multiantenna transmission scheme, designated as SM-MIMO, that associates information to the transmit antenna selection, thus enabling the reduction of the number of radiofrequency chains and , consequently, the implementation of less power consuming communication systems. The novel SM-MIMO communication scheme requires, at the receiver side, the development of new and efficient signal detection strategies of the optimal performance, is infeasible to implement due to the high computational cost. Sphere Decoding detectors (SD) are customarily applied to MIMO systems and attain optimal performance with lower computational cost.An SD algorithm, tailored following SM signal characteristics was deloped, resulting in computational cost reduction compared to ML detector and conventional MIMO SD algorithms. The hogh computational sensitivity of SD algorithms to the signal-to-noise ratio (SNR) variation motivated the development of subboptimal detection techniques. Strategies based in group detection were propsed, and nested detection algorithms LA-M and MLA-C had their complexity and performance evaluated in different configurations and channel scenarios. A new family of detectors, that performs the detection of the transmit antenna combinations and the transmitted symbols in two distinct stages,was proposed, and List-BMP-LR-MMSE algorithm attained near -optimal detection performace with low computational complexity, less sensitive to SNR variation. Based on the two-stage detection strategy, a new low-complexity detector was developed to space-time coded SM systems.
24
Lui, Feng. "Spread Spectrum Signal Detection from Compressive Measurements." International Foundation for Telemetering, 2013. http://hdl.handle.net/10150/579660.
Full textAbstract:
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NVSpread Spectrum (SS) techniques are methods used to deliberately spread the spectrum of transmitted signals in communication systems. The increased bandwidth makes detection of these signals challenging for non-cooperative receivers. In this paper, we investigate detection of Frequency Hopping Spread Spectrum (FHSS) signals from compressive measurements. The theoretical and simulated performances of the proposed methods are compared to those of the conventional methods.
25
Siciliani, Francesco. "Development of a Vehicle Stability Detection Signal." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-73718.
Full textAbstract:
It is possible to obtain information about the stability conditions of a vehicle by observing and comparing existing signals involved in the rotational motion of the vehicle around the vertical axis. Accurate information about the current state of a vehicle is critical for the development and function of new active safety features in a vehicle. Therefore, the goal of this thesis is to create a new signal based on already existing signals from the vehicle electronic control unit for detecting understeering and oversteering of a vehicle. The signal should consider all the factors that affect the evaluation of the vehicle´s stability conditions. The results show that the developed signal can, in certain conditions, detect understeering and oversteering. Issues arise in situations such as banked curves or low-mu surfaces. In those cases, the signal is not fully able to describe the vehicle behavior.
26
Khani, Shirkoohi Mehrdad. "Adaptive Neural Signal Detection for Massive MIMO." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122549.
Full textAbstract:
Thesis: S.M. in Computer Science and Engineering, Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 55-58).
Massive Multiple-Input Multiple-Output (MIMO) is a key enabler for fifth generation (5G) cellular communication systems. Massive MIMO gives rise to challenging signal detection problems for which traditional detectors are either impractical or suffer from performance limitations. Recent work has proposed several learning approaches to MIMO detection with promising results on simple channel models (e.g., i.i.d. Gaussian entries). However, we find that the performance of these schemes degrades significantly in real-world scenarios in which the channels of different receivers are spatially correlated. The root of this poor performance is that these schemes either do not exploit the problem structure (requiring models with millions of training parameters), or are overly-constrained to mimic algorithms that require very specific assumptions about the channel matrix. We propose MMNet, a deep learning MIMO detection scheme that significantly outperforms existing approaches on realistic channel matrices with the same or lower computational complexity. MMNet's design builds on the theory of iterative soft-thresholding algorithms to identify the right degree of model complexity, and it uses a novel training algorithm that leverages temporal and frequency locality of channel matrices at a receiver to accelerate training. Together, these innovations allow MMNet to train online for every realization of the channel. On i.i.d. Gaussian channels, MMNet requires 2 orders of magnitude fewer operations than existing deep learning schemes but achieves near-optimal performance. On spatially-correlated realistic channels, MMNet achieves the same error rate as the next-best learning scheme (OAMPNet [1]) at 2.5dB lower Signal-to-Noise Ratio (SNR) and with at least lOx less computational complexity. MMNet is also 4-8dB better overall than a classic linear scheme like the minimum mean square error (MMSE) detector.
by Mehrdad Khani Shirkoohi.
S.M. in Computer Science and Engineering
S.M.inComputerScienceandEngineering Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
27
Seo, Jong-Soo. "Blind fault detection and source identification using higher order statistics for impacting systems." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326784.
Full text
28
Pazaitis, Dimitrios I. "Performance improvement in adaptive signal processing algorithms." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368771.
Full text
29
Jancik, Jasper F. "Applying signal detection theory to moral decision-making." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-1/r3/jancikj/jasperjancik.pdf.
Full text
30
Hasan, Md Mahmudul. "Biomedical signal based drowsiness detection using machine learning: Singular and hybrid signal approaches." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/211388/1/Md%20Mahmudul_Hasan_Thesis.pdf.
Full textAbstract:
Drowsiness is one of the main contributors to road crashes. This research program examines the utility of drowsiness detection based on singular and hybrid approaches using physiological signals of EEG, EOG, and ECG. Four supervised machine learning models were developed to detect drowsiness levels, using physiological features known to be associated with drowsiness and performance impairment. The ground truth was subjective sleepiness responses while performing a repetitive reaction time task. The outcome of the study indicates that the selected features provided higher performance in the hybrid approaches than the singular approaches, which could be useful for future research implications.
31
Ma, Hannan. "Iterative row-column algorithms for two-dimensional intersymbol interference channel equalization complexity reduction and performance enhancement /." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Summer2010/h_ma_062110.pdf.
Full textAbstract:
Thesis (M.S. in electrical engineering)--Washington State University, August 2010.Title from PDF title page (viewed on July 28, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 51).
32
Frazer, Gordon John. "Aspects of time-varying non Gaussian non-linear signal analysis." Thesis, Queensland University of Technology, 1996. https://eprints.qut.edu.au/105546/1/T%28BE%26E%29%201032%20Aspects%20of%20time-varying%20non-Gaussian%20non-linear%20signal%20analysis.pdf.
Full textAbstract:
This thesis addresses problems in the field of time-varying, non-Gaussian, non-linear signal processing. It concentrates on developing results in the areas of time-frequency signal analysis and higher-order spectra which are linked by the developing area of time-varying higher-order spectra. Motivation comes from applying procedures developed to underwater acoustic signals. Reviews of time-frequency analysis and higher-order spectra precede the research contributions. Three appendices cover: a review of the
multiple-window spectrum estimation method, an improved procedure for computing analytic signals frequently used in time-frequency signal analysis, and an updated approach for computing Slepian sequences necessary for the multiple-window spectrogram.
33
Turner, Brandon M. "Signal detection theory a proposal for a nonparametric model /." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1243624652.
Full text
34
ALQADAH, HATIM FAROUQ. "OPTIMIZED TIME-FREQUENCY CLASSIFICATION METHODS FOR INTELLIGENT AUTOMATIC JETTISONING OF HELMET-MOUNTED DISPLAY SYSTEMS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1185838368.
Full text
35
Egea-Roca, Daniel. "Change detection techniques for GNSS signal-level integrity." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/458425.
Full textAbstract:
El gran éxito y la facilidad de uso de los sistemas de navegación global por satélite (GNSSs) ha conducido a la definición de una gran cantidad de aplicaciones basadas en GNSS sin precedentes. De hecho, la tendencia muestra una nueva era de aplicaciones basadas en GNSS, las denominadas aplicaciones críticas, en las que la integridad física de los usuarios puede estar en riesgo en caso de un fallo del sistema. Un requisito importante en estas aplicaciones es la integridad, definida como una medida de la fiabilidad y confianza que se tiene en la información proporcionada por el sistema. Los primeros algoritmos de integridad fueron diseñados para trabajar en entornos aéreos, en concreto para aviación civil. Desafortunadamente, las aplicaciones críticas basadas en GNSS suelen estar asociadas con entornos terrestres y por lo tanto los algoritmos de integridad tradicionales suelen fallar. El principal motivo son los efectos locales como interferencias, multi-camino o el denominado spoofing que nos podemos encontrar en entornos terrestres. Estos efectos se asumen que están controlados en aviación civil, pero ese no es el caso en entornos terrestres. De este modo, se necesitan nuevas técnicas de integridad para aplicaciones críticas basadas en GNSS, la denominada integridad a nivel de señal (signal-level integrity).
Esta tesis investiga nuevos algoritmos de detección con el objetivo de proporcionar una nueva generación de técnicas de integridad en GNSS. Para ello, se considera el campo de detección de cambios estadísticos (SCD). Este campo es de interés porque considera la dimensión temporal, requisito indispensable para aplicaciones críticas ya que una detección rápida es necesaria. Por lo tanto, la primera parte de esta tesis se ocupa del estudio del campo de SCD, incluyendo tanto la detección rápida de cambios (QCD) como la detección de cambios transitorios (TCD). Se aportan nuevas contribuciones en el campo de TCD, incluyendo la denominada solución FMA y su caracterización estadística. Además, resultados numéricos muestran la superioridad de nuestras contribuciones con respecto otras contribuciones en la literatura de TCD. Finalmente, para concluir nuestro estudio de SCD, lo comparamos con esquemas clásicos de detección bajo el mismo marco matemático. Esta comparación muestra la conveniencia de SCD cuando se trata de detecciones rápida.
La principal contribución de esta tesis es la aplicación del campo de SCD a la detección de amenazas e integridad en GNSS. Para ello, primero investigamos varias propiedades de la señal GNSS que pueden ser de utilidad para la detección de amenazas locales. En segundo lugar, damos un paso adelante en el campo de detección de amenazas en GNSS proponiendo un nuevo marco basado en QCD. Sin embargo, para fines de integridad es deseable un retardo limitado y es aquí donde la teoría de TCD es interesante. Por esta razón, se considera un nuevo marco basado en TCD para la detección de multi-camino y algoritmos de integridad en GNSS, lo que conduce a la provisión de la integridad de nivel de señal. Se muestra una mejora notable por la soluciones propuestas de TCD con respecto a las soluciones actuales. En la última parte de la tesis, se validan los detectores de amenazas y el algoritmo de integridad a nivel de señal propuestos. Esto se hace utilizando seles GNSS reales capturadas en el contexto de un proyecto de investigación financiado por la Comisión Europea. Los resultados obtenidos en un escenario realista muestran la mejora de la precisión y la integridad mediante el uso de la solución propuesta con respecto a los algoritmos de integridad actuales. Además, se muestra que la solución propuesta trabaja en tiempo real, siendo por lo tanto muy atractiva para mejorar los algoritmos de integridad actuales y fácilmente implementables.The provision of accurate positioning is becoming essential to our modern society. One of the main reasons is the great success and ease of use of Global Navigation Satellite Systems (GNSSs), which has led to an unprecedented amount of GNSS-based applications. In particular, the current trend shows that a new era of GNSS-based applications and services is emerging. These applications are the so-called critical applications, in which the physical safety of users may be in danger due to a miss-performance of the system. These applications have stringent requirements in terms of integrity, which is a measure of reliability and trust that can be placed on the information provided by the system. Unfortunately, GNSS-based critical applications are usually associated with terrestrial environments and original integrity algorithms usually fail. The main impairments are due to local effects such as interference, multipath or spoofing, which are assumed to be controlled in civil aviation but they are not in terrestrial environments. Thus, a new methodology for integrity is necessary in order to detect local effects and provide the additional level of integrity needed for GNSS-based critical applications; the so-called signal-level integrity. This thesis investigates novel detection algorithms with the aim of providing a new generation of integrity techniques in GNSS. For this purpose, the framework of Statistical Change Detection (SCD) is considered. This framework is of particular interest because its optimal criterion target the temporal dimension. This is an indispensable requirement for critical applications, in which a prompt detection is necessary. Therefore, the first part of this dissertation deals with the study of the field of SCD, including both Quickest Change Detection (QCD) and Transient Change Detection (TCD). Novel contributions are provided in the field of TCD, including the finite moving average solution and its statistical characterization. Numerical results show the superiority of our contributions. Finally, to conclude our study of SCD we compare it with classical detection schemes under the same mathematical framework. This comparison shows the appropriateness of SCD when dealing with timely detections. The main contribution of this thesis is the application of the SCD framework to threat detection and integrity in GNSS. To this end, we first investigate several properties of the received GNSS signal that may be useful for local threat detection. This leads us to move a step forward in the field of threat detection by proposing a novel QCD-based framework. Nonetheless, for integrity purposes a bounded delay is desirable, and it is here where TCD is of interest. For this reason, a novel TCD-based framework is considered for both multipath detection and integrity algorithms in GNSS, thus leading to the provision of signal-level integrity. A notable improvement is shown by the proposed TCD-based solutions considered in this thesis with respect to current solutions. In the last part of the thesis, the goal is to validate the proposed threat detectors and signal-level integrity algorithm using real GNSS signals. Real signal gathered in the context of an EC-funded research project is processed to show and validate the results of the implemented detectors. The results obtained in a realistic scenario show the improvement of the accuracy and integrity by using the proposed solution for signal-level integrity, with respect to current integrity algorithms. Furthermore, the proposed solution is shown to have real-time processing capabilities, thus being very attractive to improve current integrity algorithms and easily implementable in mass-market receivers.
36
Ma, Jun. "Channel estimation and signal detection for wireless relay." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37082.
Full textAbstract:
Wireless relay can be utilized to extend signal coverage, achieve spatial diversity by user cooperation, or shield mobile terminals from adverse channel conditions over the direct link. In a two-hop multi-input-multi-output (MIMO) amplify-and-forward (AF) relay system, the overall noise at the destination station (DS) consists of the colored noise forwarded from the relay station (RS) and the local white noise. We propose blind noise correlation estimation at the DS by utilizing statistics of the broadband relay channel over the RS-DS hop, which effectively improves signal detection at the DS. For further
performance improvement, we also propose to estimate the two cascaded MIMO relay channels over the source-RS and the RS-DS links at the DS based on the overall channel between the source and the DS and the amplifying matrix applied at the RS. To cancel cross-talk interference at a channel-reuse-relay-station (CRRS), we utilize the random forwarded signals of the CRRS as equivalent pilots for local coupling channel estimation and achieve a much higher post signal-to-interference ratio (SIR) than the conventional
dedicated pilots assisted cancellers without causing any in-band interference at the DS. When an OFDM-based RS is deployed on a high-speed train to shield mobile terminals from the high Doppler frequency over the direct link, inter-subchannel interference (ICI) mitigation is required at the RS. By utilizing statistics of the channel between the base station and the train, we develop both full-rate and reduced-rate OFDM transmission with inherent ICI self-cancellation via transmit and/or receive preprocessing, which achieve significant performance improvement over the existing ICI self-cancellation schemes.
37
Blanchett, Travis P. "Event detection and signal compression in digital electrocardiograms." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ39638.pdf.
Full text
38
Martel, Karl. "Signal detection of gravitational waves from eccentric binaries." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ47345.pdf.
Full text
39
Ravirala, Narayana. "Device signal detection methods and time frequency analysis." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/Ravirala_09007dcc803fea67.pdf.
Full textAbstract:
Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 18, 2008) Includes bibliographical references (p. 89-90).
40
Abujarad, Fawzy. "Ground penetrating radar signal processing for landmine detection." [S.l.] : [s.n.], 2007. http://diglib.uni-magdeburg.de/Dissertationen/2007/fawabujarad.htm.
Full text
41
Hayes, William S. "Pattern recognition and signal detection in gene finding." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/25420.
Full text
42
Ji, Kang Hyeun. "Transient signal detection using GPS position time series." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69466.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 229-243).
Continuously operating Global Positioning System (GPS) networks record station position changes with millimeter-level accuracy and have revealed transient deformations on various spatial and temporal scales. However, the transient deformation may not be easily identified from the position time series because of low signal-to-noise ratios (SNR), correlated noise in space and time and large number of sites in a network. As a systematic detection method, we use state estimation based on Kalman filtering and principal component analysis (PCA). State estimation improves the SNR in the time domain by estimating secular and transient motions and reducing the level of both white and colored noise. PCA improves the SNR in space domain by accounting for the coherence of transient motions between nearby sites. Synthetic tests show that the method is capable of detecting transient signals embedded in noisy data but complex signals (e.g., large-scale signals in space and time, multiple and/or propagating signals) are difficult to detect and interpret. We demonstrate the detection capability with two known signals in the Los Angeles basin, California: far-field coseismic offsets associated with the 1999 Hector Mine earthquake and locally-observed hydrologic deformation due to heavy rainfall in winter 2004-2005 in San Gabriel Valley. We applied the method to the daily GPS data from the Plate Boundary Observatory (PBO) network in Alaska and in the Washington State section of the Cascadia subduction zone. We have detected a transient signal whose maximum displacement is -9 mm in the horizontal and -41 mm in the vertical at Akutan volcano, Alaska, during the first half of 2008 and two previously unrecognized small slow slip events with average surface displacements less than 2 mm, which was thought to be below current GPS resolution. The detection method improves the SNR and therefore provides higher resolution for detecting weak transient signals, and it can be used as a routine monitoring system.
by Kang Hyeun Ji.
Ph.D.
43
Bland, Ross E. (Ross Edward). "Acoustic and seismic signal processing for footsetp detection." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37052.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (leaves 83-84).
The problem of detecting footsteps using acoustic and seismic sensors is approached from three different angles in this thesis. First, accelerometer data processing systems are designed to make footsteps more apparent to a human operator listening to accelerometer recordings. These systems work by modulating footstep signal energy into the ear's most sensitive frequency bands. Second, linear predictive modeling is shown to be an effective means to detect footsteps in accelerometer and microphone data. The time evolution of the third order linear prediction coefficients leads to the classical binary hypothesis testing framework. Lastly, a new method for blindly estimating the filters of a SIMO channel is presented. This method is attractive because it allows for a more tractable performance analysis.
by Ross E. Bland.
M.Eng.
44
Yi-qiang, Zhang, Zhang Qi-shan, Yang Dong-kai, Zhang Bo-chuan, Hu Rong-lei, and Li Zi-wei. "SEA SURFACE SCATTERED GPS SIGNAL DETECTION AND APPLICATION." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/605045.
Full textAbstract:
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, NevadaBackground and advantages of GPS based Remote Sensing are introduced, characteristics of forward scattered GPS signal such as polarization change, cross-correlation power variation, code delay due to the wave travel distance difference between direct and scattered signal, and cross-correlation power expansion due to sea surface roughness are discussed in detail. Working principle of the self-developed delay-mapping receiver is also presented. First data collection campaign is done at Inshore of BOHAI ocean with the delay-mapping receiver mounted on an airplane. Results show that the reflected signals has much variation than the direct signals, the code delay of the reflected signals varies as the receiver height and satellite elevation angle changes and expansion of the cross-correlation due to the wind driven surface was also demonstrated.
45
闐, 田. "Signal detection and interference avoidance in cognitive radio." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12614652/?lang=0, 2013. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12614652/?lang=0.
Full text
46
Авраменко, Віктор Васильович, Виктор Васильевич Авраменко, Viktor Vasylovych Avramenko, A. Konoplianchenko, and R. Ponomarenko. "The Method for Detection of the Reference Signal." Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/47238.
Full textAbstract:
The article describes a method for detection of the reference signal, with presence of the periodic additive noise. The characteristics of noise are unknown. The problem is reduced to finding the occurrence of a proportional relationship between some intermediate signals after a time interval equal to the period of the noise. The appearance of proportional relationship detected with using the function of disproportionality by the first order derivative.
47
Ren, Mengqi. "JOINT DETECTION-STATE ESTIMATION AND SECURE SIGNAL PROCESSING." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4662.
Full textAbstract:
In this dissertation, joint detection-state estimation and secure signal processing are studied. Detection and state estimation are two important research topics in surveillance systems. The detection problems investigated in this dissertation include object detection and fault detection. The goal of object detection is to determine the presence or absence of an object under measurement uncertainty. The aim of fault detection is to determine whether or not the measurements are provided by faulty sensors. State estimation is to estimate the states of moving objects from measurements with random measurement noise or disturbance, which typically consist of their positions and velocities over time. Detection and state estimation are typically implemented separately and state estimation is usually performed after the decision is made. In this two-stage approach, missed detection and false alarms in detection stage decrease accuracy of state estimation. In this dissertation, several joint detection and state estimation algorithms are proposed. Secure signal processing is indispensable in dynamic systems especially when an adversary exists. In this dissertation, the developed joint fault detection and state estimation approach is used to detect attacks launched by an adversary on the system and improve state estimation accuracy. The security problem in satellite communication systems is studied and a minimax anti-jammer is designed in a frequency hopping spread spectrum (FHSS)/quadrature phase-shift keying (QPSK) satellite communication system.
48
Qiao, Long. "Structural damage detection using signal-based pattern recognition." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1385.
Full text
49
Tataryn, Douglas Joseph. "Psychophysical and signal detection analyses of hypnotic anesthesia." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185845.
Full textAbstract:
Two experiments designed to study the effects of hypnotic suggestions on tactile sensitivity are reported. Experiment 1 utilized 40 subjects selected and classified into four groups according to their scores on the Stanford Scale of Hypnotic Susceptibility: Form C (SHSS:C). The effects of suggestions for anesthesia, as measured by both traditional psychophysical methods and signal detection procedures, were linearly related to hypnotic susceptibility. Experiment 2 employed the same methodologies in an application of the real-simulator paradigm, to examine the effects of suggestions for both anesthesia and hyperesthesia. A total of 19 undergraduate students were selected for their scores on the SHSS:C and classified into two groups: insusceptible simulators, who were given instructions to simulate the behavior of a highly hypnotizable person; and highly hypnotizable reals, who underwent a standard hypnotic procedure. Significant effects of hypnotic suggestion on both sensitivity and bias were found in the anesthesia condition, but not for the hyperesthesia condition. A new bias parameter, C', was derived which indicated that much of the bias found in the initial analyses was artifactual, a function of changes in sensitivity across conditions. There were no behavioral differences between reals and simulators in any of the conditions, though analyses of post-experimental interviews suggested the two groups had very different phenomenal experiences. Finally, a manipulation of response strategies induced different levels of sensitivity. The implications of these and other similar findings for signal detection theory are discussed in the context of implicit and explicit perception. Taken together, these results indicate that hypnotic suggestions can produce genuine decrements but not increments, in tactile sensitivity. The magnitude of these changes are partly a function of which perceptual system--the implicit or the explicit--is implicated in the assessment of sensitivity. Overall, these conclusions are consistent with 'neodissociation' accounts of hypnotic phenomena.
50
Cheng, ChienChun. "MIMO signal design, channel estimation, and symbol detection." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC003/document.
Full textAbstract:
Cette thèse aborde plusieurs problèmes fondamentaux des systèmes de communications sans fil avec des antennes multiples, dites systèmes MIMO (multiple input, multiple output). Les contributions se situent aussi bien au niveau des algorithmes de réception qu’au niveau de la génération du signal à l’émission.La plus grande partie de la thèse est dédiée à l’étude des algorithmes de réception. Les points abordés comprennent la modélisation et l’estimation du canal, la détection robuste des symboles, et la suppression des interférences. Un nouveau modèle de canal est proposé dans le chapitre 3 en exploitant les corrélations dans les domaines temporel, fréquentiel et spatial, et en réduisant l’espace des paramètres aux termes dominants. Ce modèle est utilisé pour proposer ensuite un estimateur de canal à faible complexité et aussi un sélecteur de mots de code pour envoyer vers l’émetteur les informations sur l’état du canal. Dans le chapitre 4, la réception robuste est étudiée pour les systèmes MIMO-OFDM sans une connaissance parfaite du canal. Des récepteurs robustes sont proposés pour les cas avec ou sans connaissance statistique du canal. La conception de récepteurs pour les systèmes MIMO-OFDM en présence d’interférence est étudiée dans le chapitre 5 et des récepteurs robustes sont proposés prenant en compte séparément l’interférence causée par les ondes pilotes et celle causée par les symboles d’une part et l’asynchronisme entre le signal et l’interférence d’autre part.Dans la deuxième partie de la thèse (chapitre 6), nous abordons les modulations spatiales qui sont particulièrement adaptées aux systèmes MIMO dans lesquels le nombre de chaines d’émission est inférieur aux nombre d’antennes. Remarquant que l’efficacité spectrale de ces systèmes reste très faible par rapport à la technique de multiplexage spatiale, nous avons développé des modulations spatiales améliorées (ESM, pour Enhanced Spatial Modulation) qui augmentent substantiellement l’efficacité spectrale. Ces modulations sont basées sur l’introduction de modulations secondaires, obtenues par interpolation. La technique ESM gagne plusieurs décibels en rapport signal à bruit lorsque les constellations du signal sont choisies de façon à avoir la même efficacité spectrale que dans les modulations spatiales conventionnellesThe aim of this thesis is to investigate multiple input multiple output (MIMO) techniques from the reception algorithms, i.e., channel estimation, symbol detection, and interference suppression, to the advanced spatial modulation (SM) transmission schemes, i.e., the signal constellation design for high performance and energy efficiency. In the reception algorithms, the proposed schemes are derived based on the detection theory, i.e., maximum likelihood (ML), linear minimum mean square error (MMSE), successive interference cancellation (SIC), combining with the statistical analysis, i.e., Bayesian linear regression and Bayesian model comparison, in order to deal with the channel uncertainty, i.e., fading, correlations, thermal noise, multiple interference, and the impact of estimation errors.In the transmission schemes, the signal constellations are targeted to find a good trade off between the average transmit energy and the minimum Euclidean distance in the signal space. The proposed schemes, denoted by enhanced SM (ESM), introduce novel modulation/antenna combinations and use them as the information bits for transmission. The number of those combinations is the double or the quadruple of the number of active antenna indices (or index combinations) in conventional SM systems, and this increases the number of bits transmitted per channel use by one or two.The results of simulations show that good system performance can be achieved with the advanced MIMO techniques. Several examples are presented in this thesis to provide insights for the MIMO system designs