Dissertations / Theses: 'Detection of symbol length'

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Kubánková, Anna. "Automatická klasifikace digitálních modulací." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-233424.

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This dissertation thesis deals with a new method for digital modulation recognition. The history and present state of the topic is summarized in the introduction. Present methods together with their characteristic properties are described. The recognition by means of artificial neural is presented in more detail. After setting the objective of the dissertation thesis, the digital modulations that were chosen for recognition are described theoretically. The modulations FSK, MSK, BPSK, QPSK, and QAM-16 are concerned. These modulations are mostly used in modern communication systems. The method designed is based on the analysis of module and phase spectrograms of the modulated signals. Their histograms are used for the examination of the spectrogram properties. They provide information on the count of carrier frequencies in the signal, which is used for the FSK and MSK recognition, and on the count of phase states on which the BPSK, QPSK, and QAM-16 are classified. The spectrograms in that the characteristic attributes of the modulations are visible are obtained with the segment length equal to the symbol length. It was found that it is possible to correctly recognize the modulation with the known symbol length at the signal-to-noise ratio at least 0 dB. That is why it is necessary to detect the symbol length prior to the spectrogram calculation. Four methods were designed for this purpose: autocorrelation function, cepstrum analysis, wavelet transform, and LPC coefficients. These methods were algorithmized and analyzed with signals disturbed by the white Gaussian noise, phase noise and with signals passed through a multipass fading channel. The method of detection by means of cepstrum analysis proved the most suitable and reliable. Finally the new method for digital modulation recognition was verified with signals passed through a channel with properties close to the real one.

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Park, Sang Woo. "Efficient blind symbol rate estimation and data symbol detection algorithms for linearly modulated signals." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2729.

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Cheng, ChienChun. "MIMO signal design, channel estimation, and symbol detection." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC003/document.

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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 conventionnelles
The 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

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Zhou, Zhou. "MIMO-OFDM Symbol Detection via Echo State Networks." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/95945.

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Echo state network (ESN) is a specific neural network structure composed of high dimensional nonlinear dynamics and learned readout weights. This thesis considers applying ESN for symbol detection in multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. A new ESN structure, namely, windowed echo state networks (WESN) is introduced to further improve the symbol detection performance. Theoretical analysis justifies WESN has an enhanced short-term memory (STM) compared with the standard ESN such that WESN can offer better computing ability. Additionally, the bandwidth spent as the training set is the same as the demodulation reference signals defined in 3GPP LTE/LTE-Advanced systems for the ESN/WESN based symbol detection. Meanwhile, a unified training framework is developed for both comb and scattered pilot patterns. Complexity analysis demonstrates the advantages of ESN/WESN based symbol detector compared to conventional symbol detectors such as linear minimum mean square error (LMMSE) and sphere decoder when the system is employed with a large number of OFDM sub-carriers. Numerical evaluations show that ESN/WESN has an improvement of symbol detection performance as opposed to conventional methods in both low SNR regime and power amplifier (PA) nonlinear regime. Finally, it demonstrates that WESN can generate a better symbol detection result over ESN.
Artificial neural networks (ANN) are widely used in recognition tasks such as recommendation systems, robotics path planning, self-driving, video tracking, image classifications, etc. To further explore the applications of ANN, this thesis considers using a specific ANN, echo state network (ESN) for a wireless communications task: MIMO-OFDM symbol detection. Furthermore, it proposed an enhanced version of the standard ESN, namely, windowed echo state network (WESN). Theoretical analyses on the short term memory (STM) of ESN and WESN show that the later one has a longer STM. Besides, the training set size of this ESN/WESN based method is chosen the same as the pilot symbols used in conventional communications systems. The algorithm complexity analysis demonstrates the ESN/WESN based method performs with lower complexity compared with conventional methods, such as linear mean square error (LMMSE) and sphere decoding. Comprehensive simulations examine how the symbol detection performance can be improved by using ESN and its variant WESN when the transmission link is non-ideal.

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Perrins, Erik. "MULTI-SYMBOL NONCOHERENT DETECTION OF MULTI-H CPM." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605816.

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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Two receivers are presented for the general case of noncoherent detection of multi-h continuous phase modulation (CPM). Both receivers yield performance gains using multi-symbol observations. The first is an existing receiver [1, 2] which has previously been applied to PCM/FM [3] and is now applied to the ARTM Tier II telemetry waveform. The second receiver is presented for the first time in this paper. The existing noncoherent receiver is found to perform poorly (and with high complexity) for the ARTM Tier II case. For single-symbol observations, the new receiver outperforms conventional FMdemodulation for both telemetry waveforms, and for multi-symbol observation lengths its performance approaches that of the optimal coherent receiver. The performance is evaluated using computer simulations. Receiver performance is also evaluated using a simple channel model with varying carrier phase. The traditional FM demodulator approach is found to outperform both receivers as channel conditions worsen.

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Geoghegan, Mark. "EXPERIMENTAL RESULTS FOR MULTI-SYMBOL DETECTION OF PCM/FM." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607605.

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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada
It has been previously shown, through computer simulations, that a multiple symbol detector can provide substantial gains in detection efficiency (nearly 3 dB) over traditional PCM/FM detectors. This is accomplished by performing correlations over multiple symbol intervals to take advantage of the memory inherent in the continuous phase PCM/FM signal. This paper presents measured hardware results, from a prototype developed for the Advanced Range Telemetry (ARTM) Project, that substantiate the previously published performance and sensitivity predictions. Furthermore, this work confirms the feasibility of applying this technology to high-speed commercial and military telemetry applications.

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Waseem, Athar, and A. H. M. Sadath Hossain. "MIMO Channel Equalization and Symbol Detection using Multilayer Neural Network." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2345.

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In recent years Multiple Input Multiple Output (MIMO) systems have been employed in wireless communication systems to reach the goals of high data rate. A MIMO use multiple antennas at both transmitting and receiving ends. These antennas communicate with each other on the same frequency band and help in linearly increasing the channel capacity. Due to the multi paths wireless channels face the problem of channel fading which cause Inter Symbol Interference (ISI). Each channel path has an independent path delay, independent path loss or path gain and phase shift, cause deformations in a signal and due to this deformation the receiver can detect a wrong or a distorted signal. To remove this fading effect of channel from received signal many Neural Network (NN) based channel equalizers have been proposed in literature. Due to high level non-linearity, NN can be efficient to decode transmitted symbols that are effected by fading channels. The task of channel equalization can also be considered as a classification job. In the data (received symbol sequences) spaces NN can easily make decision regions. Specifically, NN has the universal approximation capability and form decision regions with arbitrarily shaped boundaries. This property supports the NN to be introduced and perform the task of channel equalization and symbol detection. This research project presents the implementation of NN to be use as a channel equalizer for Rayleigh fading channels causing ISI in MIMO systems. Channel equalization has been done using NN as a classification problem. The equalizer is implemented over MIMO system of different forms using Quadrature Amplitude Modulation scheme (4QAM & 16QAM) signals. Levenberg-Marquardt (LM), One Step Secant (OSS), Gradient Descent (GD), Resilient backpropagation (Rprop) and Conjugate Gradient (CG) algorithms are used for the training of NN. The Weights calculated during the training process provides the equalization matrix as an estimate of Channel. The output of the NN provides the estimate of transmitted signals. The equalizer is assessed in terms of Symbol Error Rate (SER) and equalizer efficiency.

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Dye, Derek J. "Bandwidth and detection of packet length covert channels." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5724.

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Approved for public release; distribution is unlimited.
This thesis explores the detectability and robustness of packet length covert channels. We discovered that packet length covert channels, where a rogue user modulates the length of a Transport Control Protocol packet, can be detected while monitoring traffic of a large network. The bandwidth of these channels can be successfully estimated as well as the channels themselves detected using statistical inference. In addition, we observed that there is an inverse relationship between the volitionality in networks with respect to packet lengths and the detectability of these channels, and between packet length and channel bandwidth. For a large network like a college department, the bandwidth of a covert channel could be in the tens of megabytes over the course of a day.

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Wang, Yi. "Joint OFDM symbol detection and channel estimation over doubly selective channels." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121486.

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Orthogonal Frequency Division Multiplexing (OFDM) is a promising technique for high data rate transmission, that is widely used in modern wireless communication systems because of its good performance over frequency selective channels. However OFDM systems are sensitive to channel time variation resulting in Inter-Carrier Interference (ICI), that without suitable detection methods can degrade performance. Channel State Information (CSI) is essential to various OFDM data detection schemes and its acquisition is a critical factor, in particular over time-varying channels. This work considers a technique for integrating the Kalman filter channel estimation with a version of Sphere Decoding (SD) adapted to OFDM detection. By modelling the OFDM system in frequency domain as a Multiple Input Multiple Output (MIMO) system, we derive a powerful SD technique for data detection. By approximating the channel matrix as banded, we are able to maintain a feasible complexity for SD and deliver competitive performance when compared to other existing scheme. For acquisition of CSI, the Basis Expansion (BE) method is used to model the time-varying channels and a Kalman filter is constructed for tracking. The Kalman filter employs decision-feedback from the SD, requiring only a low pilot symbol density, and hence improves bandwidth efficiency. The performance of this scheme is evaluated by Monte-Carlo computer simulations. Results show that compared with competing algorithm, this scheme provides performance gains. When it is used over moderate time-varying LTE channels, this scheme shows good performance even in the presence of carrier phase noise.
Le multiplexage par répartition en fréquence orthogonale (OFDM, pour Orthogonal Frequency Division Multiplexing) est une technique prometteuse pour la transmission de données à haut débit. Il est largement utilisé dans les systèmes de communication sans fil actuels en raison de ses bonnes performances sur les canaux sélectifs en fréquence. Toutefois, les systèmes reposant sur l'OFDM sont sensibles aux variations de temps de voie, qui entraînent un brouillage inter-porteuses (ICI, pour Inter-Carrier Interference). En l'absence de méthodes de détection appropriée, ce brouillage peut réduire les performances. Les informations d'état de canal (CSI, pour Channel State Information) constituent un élément essentiel des divers systèmes de détection de données basés sur l'OFDM et leur acquisition est un facteur crucial, surtout sur les canaux variables en temps. La présente examine une technique permettant d'intégrer l'évaluation de canaux reposant sur un filtre de Kalman à une variante du décodage par sphères (SD, pour Sphere Decoding) adaptée à la détection OFDM. En modélisant le système d'OFDM dans le domaine fréquentiel comme un système « entrées multiples, sorties multiples » (MIMO, pour Multiple Input Multiple Output), nous obtenons une puissante technique de SD pour la détection des données. En tenant pour acquis que la matrice de canal est une matrice bande, il est possible de maintenir une complexité recelant le potentiel pour une implantation réelle du SD et d'obtenir des performances concurrentielles comparativement à d'autres systèmes existants. En ce qui a trait à l'acquisition des CSI, on utilise la méthode de l'« expansion de base » (BE, pour Basis Expansion) pour modéliser les canaux variables en temps et on crée un filtre de Kalman pour le suivi des variations de temps des canaux. Le filtre de Kalman utilise les retours de décisions tirés du SD. Il ne nécessite ainsi qu'une faible densité de symboles pilotes, ce qui accroît l'optimisation de la bande passante. Les performances de ce système sont évaluées à l'aide de simulations informatiques reposant sur la méthode de Monte-Carlo. Les résultats montrent que par rapport à l'algorithme mis en concurrence, ce système permet des gains de performance. Quand il est utilisé sur des canaux LTE (Long Term Evolution) modérément variables en temps, ce système atteint une bonne performance, même en présence de brouillage de la phase des porteuses.

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Pentukar, Sai Kiran. "OCLEP+: One-Class Intrusion Detection Using Length of Patterns." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1496147438710588.

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Liu, Ni. "Detection of trait-associated restriction fragment length polymorphisms in chicken." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55509.

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The gene encoding chicken growth hormone (GH) was isolated from a chicken genomic library. The size of the gene was 4 kb. It was digested with PstI and subcloned into pUC18. Three of the PstI fragments were used for restriction fragment length polymorphisms (RFLPs) analysis at the GH locus in two chicken strains (fat and lean line). Four polymorphic sites were detected using a PstI fragment (PII) as a probe. One polymorphism was located at a SacI restriction site (PS1), and three at MspI sites (PM1, PM2 and PM3). A method based on polymerase chain reaction (PCR) was developed for detecting polymorphisms at PM3 site. A fragment of 823 base pairs which contained the PM3 polymorphic site was amplified. Three genotypes (+/+,$-$/$-$ and +/$-$) were distinguished by examining the MspI digested PCR products in either agarose or polyacrylamide gel.
Ten anonymous cDNA clones were also isolated from a chicken liver cDNA library and used for RFLPs analysis. Three of these clones were found to be able to detected RFLPs at MspI sites in chicken strains (strain 7, 8, 9, 8R, S and K) indicating that a high frequency of genes are polymorphic and can be used as markers in mapping experiments. One of the three clones was present on a haploid genetic element. Segregation analysis showed that the inheritance of this haploid gene was determined by the genotype of the female parent.

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Martin, David J. "Detection of maximal repeating patterns and limited length repeating patterns." Master's thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-12232009-020250/.

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Sankarasubramaniam, Yogesh. "New Capacity-Approaching Codes for Run-Length-Limited Channels." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10483.

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Run-Length-Limited (RLL) channels are found in digital recording systems like the Hard Disk Drive (HDD), Compact Disc (CD), and Digital Versatile Disc (DVD). This thesis presents novel encoding algorithms for RLL channels based on a simple technique called bit stuffing. First, two new capacity-achieving variable-rate code constructions are proposed for (d,k) constraints. The variable-rate encoding ideas are then extended to (0,G/I) and other RLL constraints. Since variable-rate codes are of limited practical value, the second half of this thesis focuses on fixed-rate codes. The fixed-rate bit stuff (FRB) algorithm is proposed for the design of simple, high-rate (0,k) codes. The key to achieving high encoding rates with the FRB algorithm lies in a novel, iterative pre-processing of the fixed-length input sequence prior to bit stuffing. Detailed rate analysis for the proposed FRB algorithm is presented, and upper and lower bounds on the asymptotic (in input block length) encoding rate are derived. Several system-level issues of the proposed FRB codes are addressed, and FRB code parameters required to design rate 100/101 and rate 200/201 (0,k) codes are tabulated. Finally, the proposed fixed-rate encoding is extended to (0,G/I) constraints.

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Geoghegan, Mark. "IMPROVING THE DETECTION EFFICIENCY OF CONVENTIONAL PCM/FM TELEMETRY BY USING A MULTI-SYMBOL DEMODULATOR." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/607710.

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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
Binary PCM/FM has been widely adopted as a standard by the telemetry community. It offers a reasonable balance between detection efficiency and spectral efficiency, with very simple implementation in both the transmitter and receiver. Current technology, however, allows practical implementations of more sophisticated demodulators, which can substantially improve the detection efficiency of the waveform, with no changes to the modulator. This is accomplished by exploiting the memory inherent in the phase continuity of the waveform. This paper describes the implementation and performance of a noncoherent multi-symbol demodulator for PCM/FM. Sensitivity to offsets in carrier frequency, timing, and modulation index is also examined. Simulation results are presented which demonstrate improvements in detection efficiency of approximately 2.5 dB over traditional noncoherent single symbol detectors.

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Poudel, Sunil. "Study on Fault Detection andLocalization for Wave length Division Multiplexing Passive Optical Network." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129299.

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Wavelength division multiplexing passive optical network (WDM-PON) can meet growing bandwidth demand in access network by providing high bandwidth to the end users. Failure in the access network is becoming critical as a large volume of traffic might be affected. Therefore, an effective supervision mechanism to detect and localize the fault is required to shorten the service interruption time. Meanwhile, open access provides a certain freedom for end users to choose the service and hence boosts competition among service/network providers. On the other hand, to offer open access in WDM-PON could result in a substantial change on architectural design, e.g., multiple feeder fibers (FFs) instead of a single one may be required to connect different service/network providers. Consequently, the traditional supervision mechanisms don’t work properly in open WDM-PON. To fill in this gap, several fault supervision mechanisms to support open access in WDMPON are proposed in this thesis. They can be applied to both disjoint and co-located FF layout where the choice of providers is done through wavelength selection. The feasibility of such solutions has been validated by evaluating transmission performance. We have carried out simulations in VPItransmissionMaker for different deployment scenarios. The results have confirmed that no significant degradation of the transmission performance is introduced by the proposed monitoring schemes compared to the benchmark, where no any fault supervision method is implemented.

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Lee, Seungyup. "A rapid cycle length variability detection technique of atrial electrographs in atrial fibrillation." online version, 2008. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=case1207255208.

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Lee, Seungyup. "A RAPID CYCLE LENGTH VARIABILITY DETECTION TECHNIQUE OF ATRIAL ELECTROGRAMS IN ATRIAL FIBRILLATION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1207255208.

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Nguyen, Nam Tran Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Training signal and precoder dsigns for channel estimation and symbol detection in MIMO and OFDM systems." Awarded by:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/43243.

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Research in wireless communications has been actively carried out in recent years. In order to enable a high data transmission rate, multiple-input multiple-output (MIMO) communications has been proposed and commonly adopted. Accurate channel identification and reliable data detection are major challenges in the implementation of a communications system operating over a wireless fading channel. These issues become even more challenging in MIMO systems since there are many more parameters involved in the estimation processes. This thesis, consisting of four major parts, focuses on applying convex optimization to solve design problems in both MIMO channel estimation and data detection. The first part proposes a novel orthogonal affine precoding technique for jointly optimal channel estimation and symbol detection in a general MIMO frequency-selective fading channel. Additionally, the optimal power allocation between the data and training signals is also analytically derived. The proposed technique is shown to perform much better than other affine precoding techniques in terms of detection error probability and computational complexity. The second part is concerned with the MIMO orthogonal frequency-division multiplexing (OFDM) systems. The superimposed training technique developed in the first part is applied and extended for MIMO-OFDM systems where all the involved transmitters and receivers are assumed to be uncorrelated. Analytical and numerical results confirm that the proposed design can efficiently identify the unknown wireless channel as well as effectively recover the data symbols, while conserving the transmission bandwidth. The third part considers training and precoding designs for OFDM under colored noise environment. The superiority of the proposed design over the previously-known design under colored noise is thoroughly demonstrated. The last part of the thesis develops the orthogonal affine precoder for spatially correlated MIMO-OFDM systems. The optimal superimposed training sequences are solved by tractable semi-definite programming. To have a better computational efficiency, two approximate design techniques are also presented. Furthermore, the non-redundancy precoder proposed in the third part is employed to combat channel correlation. As a result, the proposed designs are demonstrated to outperform other known designs in terms of channel estimation and data detection.

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Danhall, Viktor. "Feature Extraction From Images of Buildings Using Edge Orientation and Length." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-12510.

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To extract information from a scene captured in digital images where the information represents some kind of feature is an important process in image analysis. Both the speed and the accuracy for this process is very important since many of the analysis applications either require analysis of very large data sets or requires the data to be extracted in real time. Some of those applications could be 2 dimensional as well as 3 dimensional object recognition or motion detection. What this work will focus on is the extraction of salient features from scenes of buildings, using a joint histogram based both the edge orientation and the edge length to aid in the extraction of the relevant features. The results are promising but will need some more refinement work to be used successfully and is therefore quite a bit of reflected theory.

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Ma, Yongteng 1974. "Multiple-symbol differential detection for differential space-time modulation in the presence of multiple cochannel interferers : Yongteng Ma." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98994.

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Space-time coding and modulation employ multiple transmit and receive antennas to improve performance over multipath fading channels. In most works on space-time coding, perfect channel state information is assumed to be available at the receiver. In many practical situations, however, it may be difficult or costly to accurately estimate the channel. In this thesis, a multiple-symbol differential detector is derived for dicyclic unitary group codes for differential space-time modulation in the presence of multiple uncorrelated equal-power cochannel interferers over a slow-fading Rayleigh channel that is unknown to the transmitter and the receiver. The covariance matrix of the interference plus noise is assumed to be known at the receiver. Under the Gaussian assumption for the aggregate interference plus noise, the maximurn-likelihood decision statistic is developed for the detector. Its pairwise error probability and bit error probability performance is evaluated by analysis and demonstrated by simulation. It is shown that the detector can efficiently suppress cochannel interference, and with an increase in observation interval, the performance of multiple-symbol differential detection approaches that of coherent detection with differential encoding and ideal channel information.

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Terzi, Evren. "Blind synchronization and detection of Nyquist pulse shaped QAM signals." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002997.

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Blears, Melissa J. "Detection of genetic variability among Cryptosporidium parvum isolates using amplified fragment length polymorphism and ribosomal RNA typing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33210.pdf.

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Mohan, Deepak. "Real-time detection of grip length deviation for fastening operations: a Mahalanobis-Taguchi system (MTS) based approach." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/DeepakMohanThesisFinal_09007dcc80410b1d.pdf.

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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 October 24, 2007) Includes bibliographical references.

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Ghorbani, Behshid. "Initial transient phase of steady state simulation : methods of its length detection and their evaluation in Akaroa2." Thesis, University of Canterbury. Computer Science and Software Engineering, 2004. http://hdl.handle.net/10092/9612.

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The start-up or initial transient problem arises in steady state, discrete-event simulation, where a selection of non-typical initial conditions introduces bias in simulated output sequences. One way of dealing with initialisation bias is to delete a portion of the output from the beginning of the run, to eliminate the effects of bias caused by these initial conditions. To make sure that the remaining observations represent steady state behaviour, it is safer to remove more than enough observations from the beginning of the run but only to an extent that not too many good observations are removed. This research focuses on the initial transient period and the proposed statistical tests for detecting its length. Our aim here is to find a statistical test that in addition to overestimating the length of the initial transient period it detects a length as accurately as possible (in finding a length as close to the one estimated by the theory).

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Park, Hyung Chul, Kwyro Lee, and Kamilo Feher. "NON-COHERENTLY DETECTED FQPSK: RAPID SYNCHRONIZATION AND COMPATIBILITY WITH PCM/FM RECEIVERS." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/606461.

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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada
A new class of non-coherent detection techniques for recently standardized Feher patented quadrature phase-shift keying (FQPSK) systems is proposed and studied by computer aided design/simulations and also verified by experimental hardware measurements. The theoretical concepts of the described non-coherent techniques are based on an interpretation of the instantaneous frequency deviation or phase transition characteristics of FQPSK-B modulated signal at the front end of the receiver. These are accomplished either by Limiter-Discriminator (LD) or by Limiter-Discriminator followed by Integrate-and-Dump (LD I&D) methods. It is shown that significant BER performance improvements can be obtained by increasing the received signal’s observation time over multiple symbols as well as by adopting trellis-demodulation. For example, our simulation results show that a BER=10^-4 can be obtained for an E(b)/N(0)=12.7 dB.

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Culha, Onur. "Noncoherent Differential Demodulation Of Cpm Signals With Joint Frequency Offset And Symbol Timing Estimation." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613729/index.pdf.

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In this thesis, noncoherent differential demodulation of CPM signals with joint carrier frequency offset and symbol timing estimation is investigated. CPM is very attractive for wireless communications owing to major properties: good spectral efficiency and a constant envelope property. In order to demodulate the received CPM signal differentially, the symbol timing and the carrier frequency offset have to be estimated accurately. There are numerous methods developed for the purpose. However, we have not encountered studies (which are based on autocorrelation estimation and hence suitable for blind synchronization) that give expectable performance for both M-ary and partial response signaling. Thus, in this thesis we analyze a feedforward blind estimation scheme, which recovers the symbol timing and the frequency offset of M-ary CPM signals and partial response CPM signals. In addition, we surveyed low complexity symbol detection methods for CPM signals. Reduced state Viterbi differential detector incorporated to the joint frequency offset and symbol timing estimator is also examined. The performance of the examined demodulator scheme is assessed for the AWGN channel by computer simulations.

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Voratovic, Dayen Chad. "Generation and Detection of Coherent Pulse Trains in Periodically Poled Lithium Niobate Through Optical Parametric Amplification." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1324406162.

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Ni, Kai. "The asymptotic rate of the length of the longest significant chain with good continuation in Bernoulli net and its applications in filamentary detection." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47683.

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This thesis is devoted to the detectability of an inhomogeneous region possibly embedded in a noisy environment. It presents models and algorithms using the theory of the longest significant run and percolation. We analyze the computational results based on simulation. We consider the length of the significant nodes in a chain with good continuation in a square lattice of independent nodes. Inspired by the percolation theory, we first analyze the problem in a tree based model. We give the critical probability and find the decay rate of the probability of having a significant run with length k starting at the origin. We find that the asymptotic rate of the length of the significant run can be powerfully applied in the area of image detection. Examples are detection of filamentary structures in a background of uniform random points and target tracking problems. We set the threshold for the rejection region in these problems so that the false positives diminish quickly as we have more samples. Inspired by the convex set detection, we also give a fast and near optimal algorithm to detect a possibly inhomogeneous chain with good continuation in an image of pixels with white noise. We analyze the length of the longest significant chain after thresholding each pixel and consider the statistics over all significant chains. Such a strategy significantly reduces the complexity of the algorithm. The false positives are eliminated as the number of pixels increases. This extends the existing detection method related to the detection of inhomogeneous line segment in the literature.

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29

Heltshe, Sonya Lenore. "Quantification of length-bias in screening trials with covariate-dependent test sensitivity /." Connect to full text via ProQuest. Limited to UCD Anschutz Medical Campus, 2007.

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Thesis (Ph.D. in Biostatistics, Department of Preventive Medicine and Biometrics) -- University of Colorado Denver, 2007.
Typescript. Includes bibliographical references (leaves 89-93). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

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30

Westberg, Daniel. "A sensor fusion method for detection of surface laid land mines." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10479.

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Landminor är ett stort problem både under och efter krigstid. De metoder som används för att detektera minor har inte ändrats mycket sedan 1940-talet. Forskning med mål att utvärdera olika elektro-optiska sensorer och metoder som skulle kunna användas för att skapa mer effektiv min-detektion genomförs på FOI. Försök som har gjorts med data från bland annat laser-radar och IR-sensorer har gett intressanta resultat.

I det här examensarbetet utvärderades olika fenomen och egenskaper i laser-radar- och IR-data. De testade egenskaperna var intensitet, IR, ytlikhet och höjd.

En metod som segmenterar intressanta objekt och bakgrundsdata utformades och implementerades. Metoden använde sig av expectation-maximization-skattning och ett minimum message length-kriterium. Ett scatter separability-kriterium användes för att bestämma kvalitén på de olika egenskaperna och på den resulterande segmenteringen.

Data insamlad under en mätkampanj av FOI användes för att testa metoden. Resultatet visade bland annat att ytlikhetsmåttet gav en bra segmentering för stora objekt med släta ytor, men var sämre för små objekt med skrovliga ytor. Vid jämförelse med en manuellt skapad mål-mask visade det sig att metoden klarade av att välja ut egenskaper som i många fall gav en godkänd segmentering.

Land mines are a huge problem in conflict time and after. Methods used to detect mines have not changed much since the 1940's. Research aiming to evaluate output from different electro-optical sensors and develop methods for more efficient mine detection is performed at FOI. Early experiments with laser radar sensors show promising results, as do analysis of data from infrared sensors.

In this thesis, an evaluation is made of features found in laser radar- and in infrared -sensor data. The tested features are intensity, infrared, a surfaceness feature extracted from the laser radar data and height above an estimated ground plane.

A method for segmenting interesting objects from background data using theexpectation-maximization algorithm and a minimum message length criterion is designed and implemented. A scatter separability criterion is utilized to determine the quality of the features and the resulting segmentation.

The method is tested on real data from a field trial performed by FOI. The results show that the surfaceness feature supports the segmentation of larger object with smooth surfaces but gives no contribution to small object with irregular surfaces. The method produces a decent result of selecting contributing features for different neighbourhoods of a scene. A comparison with a manually created target mask of the neighbourhood and the segmented components show that in most cases a high percentage separation of mine data and background data is possible.

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Kippenberger, Roger Miles. "On Real Time Digital Phase Locked Loop Implementation with Application to Timing Recovery." Thesis, University of Canterbury. Electrical and Computer Engineering, 2006. http://hdl.handle.net/10092/1146.

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In digital communication systems symbol timing recovery is of fundamental importance. The accuracy in estimation of symbol timing has a direct effect on received data error rates. The primary objective of this thesis is to implement a practical Digital Phase Locked Loop capable of accurate synchronisation of symbols suffering channel corruption typical of modern mobile communications. This thesis describes an all-software implementation of a Digital Phase Locked in a real-time system. A timing error detection (TED) algorithms optimally implemented into a Digital Signal Processor. A real-time transmitter and receiver system is implemented in order to measure performance when the received signal is corrupted by both Additive White Gaussian Noise and Flat Fading. The Timing Error Detection algorithm implemented is a discrete time maximum likelihood one known as FFML1, developed at Canterbury University. FFML1 along with other components of the Digital Phase Locked loop are implemented entirely in software, using Motorola 56321 assembly language.

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Iyamabo, Philip Ehizogie. "Exact BER Calculation of TCM-MAPSK using Pairwise Probability of Product Trellis Algorithm for DVB Applications." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481247472348161.

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33

Charalsawadi, Chariyawan. "Mosaicism for trisomy21: Utility of array-based technology for its detection and its influence on telomere length and the frequency of acquired chromosome abnormalities." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2546.

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The primary aim of this study was to determine the effectiveness of array-based technology for detecting and quantifying the presence of mosaicism. This aim was achieved by studying individuals having mosaicism for Down syndrome. SNP arrays were performed on 13 samples from individuals with mosaicism for trisomy 21, 13 samples from individuals with normal chromosome 21complements (negative controls) and 5 samples from individuals with full or partial trisomy 21 (positive controls). In addition, BAC arrays were processed on 6 samples from individuals with mosaicism for trisomy 21, 3 negative controls and 1 positive control. These studies have shown that array-based technology is effective for detecting mosaicism that is present in 20% or more cells with the results being consistent for both platforms. We also demonstrated the strength of array-based technology to identify previously unrecognized chromosomal mosaicism. A second aim of this study was to gain insight regarding the effect that trisomy 21 has on telomere attrition and the frequency of chromosomal instability. This study provides the first reported measure of both chromosome-specific telomere lengths and the frequency of acquired chromosome abnormalities in trisomic cells and isogenic euploid cells obtained from the same individuals. A chromosome-specific telomere length assay was performed on lymphocytes obtained from 24 young individuals with mosaicism for Down syndrome. While differences in overall telomere signal intensities were observed between the euploid and trisomic cells within a person, strikingly similar profiles for chromosome-specific telomere intensities were observed between the cell types within a person. Analyses were also completed on lymphoblast samples obtained from 8 older individuals with mosaicism for Down syndrome, including 5 individuals without dementia and 3 individuals with dementia. In the older study subjects, a significant inverse correlation was observed between telomere length and the frequency of micronuclei, suggesting that telomeric shortening is leading to an increased frequency of chromosomal instability, possibly through dicentric chromosome formation. However, further studies of more individuals, especially additional analyses of older individuals, are needed. These future studies may help to identify genomic regions of interest and serve to inform investigators of potential candidate genes in the etiology of dementia.

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Bald-Blume, Niklas [Verfasser]. "Luminex xTAG detection of Cucumber mosaic virus (CMV) and different tospoviruses as well as further characterization of CMV with infectious full-length clones and pseudorecombinants / Niklas Bald-Blume." Hannover : Technische Informationsbibliothek (TIB), 2016. http://d-nb.info/1122664087/34.

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35

Argyriou, Andreas. "Probability of symbol error for coherent and non-coherent detection of M-ary frequency-shift keyed (MFSK) signals affected by co-channel interference and additive white Gaussian noise (AWGN) in a fading channel." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA376826.

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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, March 2000.
Thesis advisor(s): Lebaric, Jovan; Robertson, Clark. Includes bibliographical references (p. 289). Also available online.

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Li, Lingjun. "Statistical Inference for Change Points in High-Dimensional Offline and Online Data." Kent State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=kent1586206330858843.

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Lemos, Gléverson Fabner Condé. "Técnicas de detecção e implementação em FPGA de modulações QAM de ordem elevada." Universidade Federal de Juiz de Fora (UFJF), 2011. https://repositorio.ufjf.br/jspui/handle/ufjf/4724.

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A presente dissertação versa sobre técnicas de baixo custo para detecção, modulação e demodulação de constelações M-QAM (quadrature amplitude modulation) de ordem elevada, ou seja, M = 2n, n = {2,3, · · · ,16}. Al´em disso, s˜ao propostas constelações alternativas para M-QAM, M = 22n, n = {1,2, · · · ,8}, que buscam minimizar a PAPR (peak to average power ratio) quando um sistema OFDM (orthogonal frequency division multiplexing) ´e utilizado para a transmissão de dados. Uma implementação, de baixo custo e em dispositivo FPGA (field programmable gate array), de um esquema de modulação constante e adaptativa para sistemas OFDM, quando a modulação é MQAM, M = 22n, n = {1,2, · · · ,8}, é descrita e analisada. O desempenho das técnicas de detecção propostas é avaliado através de simulações computacionais quando o ruído é AWGN (additive white Gaussian noise) e AIGN (additive impulsive Gaussian noise). Os resultados em termos de BER × Eb/N0 indicam que as perdas de desempenho geradas com as técnicas propostas não são significativas e, portanto, tais técnicas são candidatas adequadas para a implementação de um sistema OFDM com elevada eficiência espectral. Os resultados computacionais revelam ainda que as propostas alternativas para constelações M-QAM reduzem a PAPR, mas, em contrapartida, degradam consideravelmente a BER. Finalmente, a análise da complexidade computacional das técnicas de detecção e demodulação, as quais foram implementadas em dispositivo FPGA, indica que há uma redução do custo computacional, ou seja, redução do uso de recursos de hardware do dispositivo FPGA quando tais técnicas são implementadas para a demodulação e detecção de símbolos M-QAM de ordem elevada.
This dissertation deals with low-cost techniques for detection, modulation and demodulation of high order M-QAM (quadrature amplitude modulation) constellations, i.e., M = 2n, n = {2,3, · · · ,16}. In addition, alternative constellations are proposed to M-QAM, M = 22n, n = {1,2, · · · ,8}, which seek to minimize the PAPR (peak to average power ratio) when an OFDM (orthogonal frequency division multiplexing) system is used for data transmission. A low-cost implementation using a FPGA (field programmable gate array) device of a modulation scheme for constant and adaptive OFDM systems when the modulation is M-QAM, M = 22n, n = {1,2, · · · ,8}, is described and analyzed. The performance of the proposed detection techniques is evaluated through computer simulations when the noise is AWGN (additive white Gaussian noise) and AIGN (additive impulsive Gaussian noise). The results in terms of BER × Eb/N0 indicate that the performance losses generated by the proposed techniques are not significant and, therefore, such techniques are appropriate candidates for the implementation of an OFDM system with high spectral efficiency. The computational results reveal that the alternative proposals for M-QAM constellations reduce the PAPR, but, considerably degrade the BER. Finally, the analysis of computational complexity of detection and demodulation techniques, which were implemented in a FPGA device, indicates that there is a computational cost reduction, i.e., a reduction of resource usage of hardware device such as FPGA when these techniques are implemented for the demodulation and detection of high-order M-QAM symbols.

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38

Bauer, Michael. "Dynamical characterization of Markov processes with varying order." Master's thesis, [S.l. : s.n.], 2009. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200900153.

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Palkki, Ryan D. "Chemical identification under a poisson model for Raman spectroscopy." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45935.

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Raman spectroscopy provides a powerful means of chemical identification in a variety of fields, partly because of its non-contact nature and the speed at which measurements can be taken. The development of powerful, inexpensive lasers and sensitive charge-coupled device (CCD) detectors has led to widespread use of commercial and scientific Raman systems. However, relatively little work has been done developing physics-based probabilistic models for Raman measurement systems and crafting inference algorithms within the framework of statistical estimation and detection theory. The objective of this thesis is to develop algorithms and performance bounds for the identification of chemicals from their Raman spectra. First, a Poisson measurement model based on the physics of a dispersive Raman device is presented. The problem is then expressed as one of deterministic parameter estimation, and several methods are analyzed for computing the maximum-likelihood (ML) estimates of the mixing coefficients under our data model. The performance of these algorithms is compared against the Cramer-Rao lower bound (CRLB). Next, the Raman detection problem is formulated as one of multiple hypothesis detection (MHD), and an approximation to the optimal decision rule is presented. The resulting approximations are related to the minimum description length (MDL) approach to inference. In our simulations, this method is seen to outperform two common general detection approaches, the spectral unmixing approach and the generalized likelihood ratio test (GLRT). The MHD framework is applied naturally to both the detection of individual target chemicals and to the detection of chemicals from a given class. The common, yet vexing, scenario is then considered in which chemicals are present that are not in the known reference library. A novel variation of nonnegative matrix factorization (NMF) is developed to address this problem. Our simulations indicate that this algorithm gives better estimation performance than the standard two-stage NMF approach and the fully supervised approach when there are chemicals present that are not in the library. Finally, estimation algorithms are developed that take into account errors that may be present in the reference library. In particular, an algorithm is presented for ML estimation under a Poisson errors-in-variables (EIV) model. It is shown that this same basic approach can also be applied to the nonnegative total least squares (NNTLS) problem. Most of the techniques developed in this thesis are applicable to other problems in which an object is to be identified by comparing some measurement of it to a library of known constituent signatures.

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40

Nhan, Nhat-Quang. "Optimisation de précodeurs linéaires pour les systèmes MIMO à récepteurs itératifs." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0062/document.

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Les standards « Long-term evolution » (LTE) et LTE-Advanced (LTE-A) devraient influencer fortement l’avenir de la cinquième génération (5G) des réseaux mobiles. Ces normes exigent de hauts débits de données et une qualité de service de très bon niveau, ce qui permet d’assurer un faible taux d’erreur, avec une faible latence. Par ailleurs, la complexité doit être limitée. Dans le but de déterminer des solutions technologiques modernes qui satisfont ces contraintes fortes, nous étudions dans la thèse des systèmes de communication sans fil MIMO codés. D’abord, nous imposons un simple code convolutif récursif systématique (RSC) pour limiter la complexité et la latence. En considérant des récepteurs itératifs, nous optimisons alors la performance en termes de taux d’erreur de ces systèmes en définissant un précodage linéaire MIMO et des techniques de mapping appropriées. Dans la deuxième partie de la thèse, nous remplaçons le RSC par un LDPC non-binaire (NB-LDPC). Nous proposons d’utiliser les techniques de précodage MIMO afin de réduire la complexité des récepteurs des systèmes MIMO intégrant des codes NB-LDPC. Enfin, nous proposons également un nouvel algorithme de décodage itératif à faible complexité adapté aux codes NB-LDPC
The long-term evolution (LTE) and the LTE-Advanced (LTE-A) standardizations are predicted to play essential roles in the future fifth-generation (5G) mobile networks. These standardizations require high data rate and high quality of service, which assures low error-rate and low latency. Besides, as discussed in the recent surveys, low complexity communication systems are also essential in the next 5G mobile networks. To adapt to the modern trend of technology, in this PhD thesis, we investigate the multiple-input multiple-output (MIMO) wireless communication schemes. In the first part of this thesis, low-complex forward error correction (FEC) codes are used for low complexity and latency. By considering iterative receivers at the receiver side, we exploit MIMO linear precoding and mapping methods to optimize the error-rate performance of these systems. In the second part of this thesis, non-binary low density parity check (NB-LDPC) codes are investigated. We propose to use MIMO precoders to reduce the complexity for NB-LDPC encoded MIMO systems. A novel low complexity decoding algorithm for NB-LDPC codes is also proposed at the end of this thesis

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41

Grymel, Martin-Thomas. "Error control with binary cyclic codes." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/error-control-with-binary-cyclic-codes(a5750b4a-e4d6-49a8-915b-3e015387ad36).html.

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Error-control codes provide a mechanism to increase the reliability of digital data being processed, transmitted, or stored under noisy conditions. Cyclic codes constitute an important class of error-control code, offering powerful error detection and correction capabilities. They can easily be generated and verified in hardware, which makes them particularly well suited to the practical use as error detecting codes.A cyclic code is based on a generator polynomial which determines its properties including the specific error detection strength. The optimal choice of polynomial depends on many factors that may be influenced by the underlying application. It is therefore advantageous to employ programmable cyclic code hardware that allows a flexible choice of polynomial to be applied to different requirements. A novel method is presented in this thesis to realise programmable cyclic code circuits that are fast, energy-efficient and minimise implementation resources.It can be shown that the correction of a single-bit error on the basis of a cyclic code is equivalent to the solution of an instance of the discrete logarithm problem. A new approach is proposed for computing discrete logarithms; this leads to a generic deterministic algorithm for analysed group orders that equal Mersenne numbers with an exponent of a power of two. The algorithm exhibits a worst-case runtime in the order of the square root of the group order and constant space requirements.This thesis establishes new relationships for finite fields that are represented as the polynomial ring over the binary field modulo a primitive polynomial. With a subset of these properties, a novel approach is developed for the solution of the discrete logarithm in the multiplicative groups of these fields. This leads to a deterministic algorithm for small group orders that has linear space and linearithmic time requirements in the degree of defining polynomial, enabling an efficient correction of single-bit errors based on the corresponding cyclic codes.

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Pulido, Herrera Edith. "Improving Data Fusion in User Positioning Systems." Doctoral thesis, Universitat Jaume I, 2009. http://hdl.handle.net/10803/10485.

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A fault detection and correction methodology for user positioning systems based on Kalman filtering is presented in this thesis. To develop this methodology, various aspects of the design of positioning systems are taken into account, such as the dynamic models of the systems, the definition of the estimation technique, the available technology and the environment (to identify disturbances that can affect the systems).
In the first phase, the available technologies were identified, and the algorithms and the physical-mathematical models were defined for the positioning systems for both indoor and outdoor environments. The Dead Reckoning (DR) algorithm was included for this reason, because it can be applied in both environments. This algorithm allows the pedestrian's position to be obtained while s/he is walking. Given that one of the main parameters of DR is the pedestrian's step length, a careful analysis was carried out to determine it. Algorithms that allow, first, detection of a step and, second, calculation of its length are therefore presented here.
An integrated system based on UWB and inertial technologies (IMU) is proposed for indoor environments. This system uses the information about the step length to improve the information provided by the UWB system. The system that was defined for outdoor environments is a GPSIMU system based on the DR algorithm. Data fusion is carried out by means of Kalman filtering for both systems. In the GPSIMUDR system, the errors of the azimuth bias and the step length are obtained by means of Kalman filtering, which allows the DR parameters to be corrected and, consequently, the pedestrian's position can be obtained with greater accuracy.
In the next phase, the fault detection and correction methodology is developed. This is based on the principles of causal diagnosis using the theory of possibility. This methodology is proposed in order to prevent the introduction of erroneous information into the Kalman filter. In order to carry this out, failure states of the sensor systems are defined and corrective measures are applied when one or more of those states are present. These states are defined taking into account the empirical knowledge of the behaviour of the system. The performance of the filters was also monitored. This consists in the continuous evaluation of their innovations and, in case of inconsistency, corrective measures are applied to the parameters of the filters.
The experiments, for the proposed systems, presented results that improved their initial response to a considerable degree. For the UWBIMU system, an analysis that involves the detection of inconsistencies of the filter is presented, while for the GPSIMUDR system the fault detection and correction methodology is applied. In the UWBIMU system, the corrective measures introduced into to the Kalman filter allowed both consistent filtering and a soft signal to be obtained, i.e. most of the reflections of the signal provided by the UWB system were eliminated. The results of the GPSIMUDR system indicated that by implementing the methodology developed here, consistent filtering was obtained and the values of the azimuth and the step length were corrected properly. As a result more exact pedestrian trajectories were obtained.

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YANG, YI-TUN, and 楊奕敦. "Effect Of DFE Length On Minimum Symbol Error Rate." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/38199465615130037538.

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碩士
淡江大學
電機工程學系
91
In this paper , first we will derive a generalized formula for the decision error probability for linear equalizer and decision feedback equalizer in bandlimited channels employing M-ary PAM transmission. The formula applies to any assignment of equalizer tap weights, whether the weights are in optimum condition or non-optimum condition. It is also valid for Minimum Mean Square Error(MMSE) and Zero forcing criterion. And it is valid for Least Mean Square, Recursive Least Square(RLS), or other algorithms. Next, by applying the gradient search method to this generalized formula to obtain the minimum symbol error rate, we call this algorithm as GMSER(Generalized Minimum Symbol Error Rate). For high level M-ary PAM, the computational complexity of GMSER is increased. The SGMSER(Stochastic GMSER) algorithm is obtained by further simplification of GMSER to reduce the computational complexity in GMSER. Then using different transmitted channels for simulation, we demonstrate that SGMSER and GMSER will converge to the same symbol error rate. And we will observe the effect on symbol error rate of different lengths of the decision feedback equalizer. The results show that GMSER (or SGMSER) can provide better performance than MMSE.

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Lo, Lih-shang, and 羅立聲. "Performance of coded multiple symbol differential detection." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/75682795574412063802.

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碩士
國立臺灣大學
電機工程研究所
84
In this thesis,we study coded differential detection techniques. We proposed a new technique calledruned Maximum Likelihood Differential DetectionPML - DD ) which is a method which can reduce thetates in the sequential detection.A modification ofML-DD is also proposed to further improve the per-ormance. We also apply a recently proposed tech-ique called differential detection using Weightedhase References (WPR) to coded modulation systems.imulations are provided to demostrate the interest-ng performances of the proposed coded differentialetection techniques.

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Stamatelos, Georgios. "Comparison of optimum sequence and optimum symbol-by-symbol detection in convolutional codes decoding." Thesis, 1987. http://spectrum.library.concordia.ca/2761/1/ML44234.pdf.

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Cheng, Chien-Chun, and 鄭乾君. "MIMO Signal Design, Channel Estimation, and Symbol Detection." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/79237981996936869968.

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博士
國立交通大學
電信工程研究所
104
The aim of this thesis is to investigate multiple input multiple output (MIMO) techniques from the reception algorithms to the advanced spatial modulation (SM) transmission schemes. In the reception algorithms, the proposed schemes are derived based on the detection theory, i.e., maximum likelihood, linear minimum mean square error, successive interference cancellation, 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 transmit energy and the minimum Euclidean distance in the signal space. The proposed schemes, denoted by enhanced SM, 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.

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Govender, Nishkar Balakrishna. "Adaptive multiple symbol decision feedback for non-coherent detection." Thesis, 2006. http://hdl.handle.net/10413/1562.

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Non-coherent detection is a simple form of signal detection and demodulation for digital communications. The main drawback of this detection method is the performance penalty incurred, since the channel state information is not known at the receiver. Multiple symbol detection (MSD) is a technique employed to close the gap between coherent and non-coherent detection schemes. Differentially encoded JW-ary phase shift keying (DM-PSK) is the classic modulation technique that is favourable for non-coherent detection. The main drawback for standard differential detection (SDD) has been the error floor incurred for frequency flat fading channels. Recently a decision feedback differential detection (DFDD) scheme, which uses the concept of MSD was proposed and offered significant performance gain over the SDD in the mobile flat fading channel, almost eliminating the error floor. This dissertation investigates multiple symbol decision feedback detection schemes, and proposes alternate adaptive strategies for non-coherent detection. An adaptive algorithm utilizing the numerically stable QR decomposition that does not require training symbols is proposed, named QR-DFDD. The QR-DFDD is modified to use a simpler QR decomposition method which incorporates sliding windows: QRSW-DFDD. This structure offers good tracking performance in flat fading conditions, while achieving near optimal DFDD performance. A bit interleaved coded decision feedback differential demodulation (DFDM) scheme, which takes advantage of the decision feedback concept and iterative decoding, was introduced by Lampe in 2001. This low complexity iterative demodulator relied on accurate channel statistics for optimal performance. In this dissertation an alternate adaptive DFDM is introduced using the recursive least squares (RLS) algorithm. The alternate iterative decoding procedure makes use of the convergence properties of the RLS algorithm that is more stable and achieves superior performance compared to the DFDM.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2006.

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Chung, Yi-Ping, and 鐘一評. "Multiple Symbol Differential Detection of BPSK in CDMA System." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/99720619639918575758.

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碩士
國立中山大學
電機工程學系研究所
89
In this thesis, we take an application of multiple symbol differential detection (MSDD) technique in direct-sequence code division multiple access (CDMA) system. It is well- known that MSDD is an effective noncoherent demodulator which outperform the conventional M-ary differential phase shift keying (MDPSK) in additive white Gaussian noise (AWGN) channel. Take MPSK demodulator into consideration, the performance of MSDD based on noncoherent demodulation approaches the performance of coherent demodulation. However, there is little research about MSDD in frequency-selective fading channel. We are now combining the MSDD and Rake receiver to be the signal demodulator. In conventional, there are two kinds of Rake receivers. One is coherent demodulator. Another is noncoherent demodulator. For coherent demodulation, it needs to have channel estimation at each path. The advantage is that the performance will be improved. On the other hand, the disadvantage is complexity and operation will increase. On the contrast, for noncoherent demodulation, it is the performance degradation and complexity simplification. In this thesis, We suggest a multiple symbol differential detection on Rake receiver for CDMA system. From our computer simulation, only for hard decision, the performance is improved and the improvement is proportional to the number of multipath and the number of the length of multiple symbol. This will not happen in conventional MDPSK. However, from our observation, the improvement of performance is degrading as the number of multipath increase. Thus, we employee the technique of Viterbi decoding differential detection (VDDD) to demodulate the differential sequence. By the property of decision interval, the VDDD can obtain additional improvement.

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49

(6861506), Yuxi Zhang. "CNN-based Symbol Recognition and Detection in Piping Drawings." Thesis, 2019.

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Piping is an essential component in buildings, and its as-built information is critical to facility management tasks. Manually extracting piping information from legacy drawings that are in paper, PDF, or image format is mentally exerting, time-consuming, and error-prone. Symbol recognition and detection are core problems in the computer-based interpretation of piping drawings, and the main technical challenge is to determine robust features that are invariant to scaling, rotation, and translation. This thesis aims to use convolutional neural networks (CNNs) to automatically extract features from raw images, and consequently, to locate and recognize symbols in piping drawings.

In this thesis, the Spatial Transformer Network (STN) is applied to improve the performance of a standard CNN model for recognizing piping symbols, and the Faster Region-based Convolutional Neural Network (Faster RCNN) is adopted to exploit its capacity in symbol detection. For experimentation, the synthetic data are generated as follows. Two datasets are generated for symbol recognition and detection, respectively. For recognition, eight types of symbols are synthesized based on the geometric constraints between the primitives. The drawing samples for detection are manually sketched using AutoCAD MEP software and its piping component library, and seven types of symbols are selected from the piping component library. Both sets of samples are augmented with various scales, rotations, and random noises.

The experiment for symbol recognition is conducted and the accuracies of the recognition accuracy of the CNN + STN model and the standard CNN model are compared. It is observed that the spatial transformer layer improves the accuracy in classifying piping symbols from 95.39% to 98.26%. For the symbol detection task, the experiment is conducted using a public implementation of Faster RCNN. The mean Average Precision (mAP) is 82.8% when Intersection over Union (IoU) threshold equals to 0.5. Imbalanced data (i.e., imbalanced samples in each class) led to a decrease in the Average Precision in the minority class. Also, the symbol library, the small dataset, and the complex backbone network limit the generality of the model. Future work will focus on the collection of larger set of drawings and the improvement of the network’s geometric invariance.

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Wei, Xiu-Ru, and 魏秀如. "Differential Encoding by a Table for Multiple-Symbol Differential Detection." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/17110639516459139438.

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碩士
國立中央大學
通訊工程研究所
99
Differential encoding by a look-up table for QAM was proposed recently. In this thesis, but not by a rule,using differential encoding by a table for multiple- symbol differential detection.The transmitted symbol can be obtained by looking up this read-only table according to the previously transmitted multiple symbol and data bits.Using a table for differential encoding has the advantages of both low complexity and good error performance.The results show that, differential encoding by a table is equivalent to differential encoding by a trellis. Besides Viterbi algorithm to further lower error performance.

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Dissertations / Theses on the topic 'Detection of symbol length'

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