Tesi: "Least-Square estimator"

1

Doheny, David A. "Real Time Digital Signal Processing Adaptive Filters for Correlated Noise Reduction in Ring Laser Gyro Inertial Systems". [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000306.

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2

Zhang, Zongjun. "Adaptive Robust Regression Approaches in data analysis and their Applications". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1445343114.

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3

Moda, Hari Priya. "Non-Negative Least Square Optimization Model for Industrial Peak Load Estimation". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/36003.

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Load research is the study of load characteristics on a power distribution system which helps planning engineer make decisions about equipment ratings and future expansion decisions. As it is expensive to collect and maintain data across the entire system, data is collected only for a sample of customers, where the sample is divided into groups based upon the customer class. These sample measurements are used to calculate the load research factors like kWHr-to-peak kW conversion factors, diversity factors and 24 hour average consumption as a function of class, month and day type. These factors are applied to the commonly available monthly billing kW data to estimate load on the system. Among various customers on a power system, industrial customers form an important group for study as their annual kWHr consumption is among the highest. Also the errors with which the estimates are calculated are also highest for this class. Hence we choose the industrial class to demonstrate the Lawson-Hanson Non-Negative Least Square (NNLS) optimization technique to minimize the residual squared error between the estimated loads and the SCADA currents on the system. Five feeders with industrial dominant customers are chosen to demonstrate the improvement provided by the NNLS model. The results showed significant improvement over the Nonlinear Load Research Estimation (NLRE) method.
Master of Science

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4

Mbah, Alfred Kubong. "On the theory of records and applications". [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002216.

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5

Gaspard, Guetchine. "FLOOD LOSS ESTIMATE MODEL: RECASTING FLOOD DISASTER ASSESSMENT AND MITIGATION FOR HAITI, THE CASE OF GONAIVES". OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1236.

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This study aims at developing a model to estimate flood damage cost caused in Gonaives, Haiti by Hurricane Jeanne in 2004. In order to reach this goal, the influence of income, inundation duration and inundation depth, slope, population density and distance to major roads on the loss costs was investigated. Surveyed data were analyzed using Excel and ArcGIS 10 software. The ordinary least square and the geographically weighted regression analyses were used to predict flood damage costs. Then, the estimates were delineated using voronoi geostatistical map tool. As a result, the factors account for the costs as high as 83%. The flood damage cost in a household varies between 24,315 through 37,693 Haitian Gourdes (approximately 607.875 through 942.325 U.S. Dollars). Severe damages were spotted in the urban area and in the rural section of Bassin whereas very low and low losses are essentially found in Labranle. The urban area was more severely affected by comparison with the rural area. Damages in the urban area are estimated at 41,206,869.57USD against 698,222,174.10 17,455,554.35USD in the rural area. In the urban part, damages were more severe in Raboteau-Jubilée and in Downtown but Bigot-Parc Vincent had the highest overall damage cost estimated at 9,729,368.95 USD. The lowest cost 7,602,040.42USD was recorded in Raboteau. Approximately, 39.38% of the rural area underwent very low to moderate damages. Bassin was the most severely struck by the 2004 floods, but Bayonnais turned out to have the highest loss cost: 4,988,487.66 USD. Bassin along with Labranle had the least damage cost, 2,956,131.11 and 2,268,321.41 USD respectively. Based on the findings, we recommended the implementation and diversification of income-generating activities, the maintenance and improvement of drains, sewers and gullies cleaning and the establishment of conservation practices upstream of the watersheds. In addition, the model should be applied and validated using actual official records as reference data. Finally, the use of a calculation-based approach is suggested to determine flood damage costs in order to reduce subjectivity during surveys.

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6

Savaux, Vincent. "Contribution to multipath channel estimation in an OFDM modulation context". Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00988283.

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In wireless communications systems, the transmission channel between the transmitter and the receiver antennas is one of the main sources of disruption for the signal. The multicarrier modulations, such as the orthogonal frequency division multiplexing (OFDM), are very robust against the multipath effect, and allow to recover the transmitted signal with a low error rate, when they are combined with a channel encoding. The channel estimation then plays a key role in the performance of the communications systems. In this PhD thesis, we study techniques based on least square (LS) and minimum mean square error (MMSE) estimators. The MMSE is optimal, but is much more complex than LS, and requires the a priori knowledge of the second order moment of the channel and the noise. In this presentation, two methods that allow to reach a performance close to the one of LMMSE while getting around its drawback are investigated. In another way, a third part of the presentation investigates the errors of estimation due to the interpolations.

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7

Tout, Bilal. "Identification of human-robot systems in physical interaction : application to muscle activity detection". Electronic Thesis or Diss., Valenciennes, Université Polytechnique Hauts-de-France, 2024. https://ged.uphf.fr/nuxeo/site/esupversions/36d9eab3-c170-4e40-abb6-e6b4e27aeee2.

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Ces dernières années, l’interaction physique humain-robot est devenue un sujet de recherche important, par exemple pour des applications de rééducation. Cette thèse vise à améliorer ces interactions, dans le cadre du développement de contrôleurs basés modèles, par des approches d’identification paramétrique des modèles des systèmes en interaction. Le but est de développer des méthodes d’identification en tenant compte de la variabilité et de la complexité du corps humain, et en n'utilisant que les capteurs du système robotique pour éviter l'ajout de capteurs externes. Les différentes approches présentées dans cette thèse sont testées expérimentalement avec un système robotique à un degré de liberté (1-DDL) permettant d'interagir avec la main d'une personne.Après un 1er chapitre présentant l'état de l'art, le 2e chapitre aborde les méthodes d'identification développées en robotique ainsi que la problématique du filtrage, analysée en simulation et expérimentalement. La question du réglage du filtre passe-bas est adressée, et en particulier le choix de la fréquence de coupure qui reste délicate pour un système non-linéaire. Pour surmonter ces difficultés, une technique de filtrage utilisant un filtre de Kalman étendu (EKF) est développée à partir du modèle dynamique du robot. La formulation EKF proposée permet un réglage en fonction des propriétés connues du capteur et de la confiance dans l’estimation initiale des paramètres. Cette méthode est comparée en simulation puis expérimentalement avec différentes méthodes existantes en analysant la sensibilité à l’initialisation et au réglage du filtre. Les résultats montrent que la méthode proposée est prometteuse si l’EKF est correctement réglé.Le 3e chapitre porte sur l'identification en continu des paramètres du modèle dynamique d'un système passif en interaction avec un système robotique, en combinant des méthodes d’identification de la charge utile avec des algorithmes en ligne, sans capteurs externes. Ces méthodes sont validées en simulation et expérimentalement en utilisant le système à 1-DDL dont la poignée est attachée à des bandes élastiques pour imiter une articulation humaine passive. L’analyse de l’effet de l’ajustement des méthodes en ligne met en évidence qu’un compromis est nécessaire entre la vitesse de convergence et la précision des estimations des paramètres. Enfin, la comparaison des méthodes d’identification de la charge utile montre que les méthodes identifiant séparément les paramètres du système robotique et de l’humain passif donnent une meilleure précision et une plus faible complexité de calcul.Le 4e chapitre porte sur l'identification durant l'interaction humain-système robotique. Un modèle à raideur quadratique est proposé afin de mieux représenter le comportement de l’articulation humaine passive qu’un modèle linéaire. Par la suite, ce modèle est utilisé avec une méthode d’identification itérative basée sur le rejet d’outliers, pour détecter l’activité musculaire de l’humain sans capteurs externes. Cette méthode est comparée expérimentalement à une méthode non-itérative utilisant des signaux d’électromyographie (EMG), en adaptant le système à 1-DDL pour interagir avec le poignet et permettre d’évaluer l’activité des muscles fléchisseurs et extenseurs de deux sujets. La méthode itérative proposée sans signaux EMG donne des résultats proches de ceux obtenus avec la méthode utilisant les signaux EMG lorsqu’un modèle représentant bien le comportement de l’articulation humaine passive est choisi. Les résultats de détection de l’activité musculaire obtenus avec ces deux méthodes montrent un niveau de similarité satisfaisant avec ceux obtenus directement à partir des signaux EMG
Over the last years, physical human-robot interaction has become an important research subject, for example for rehabilitation applications. This PhD aims at improving these interactions, as part of model-based controllers development, using parametric identification approaches to identify models of the systems in interaction. The goal is to develop identification methods taking into account the variability and complexity of the human body, and only using the sensor of the robotic system to avoid adding external sensors. The different approaches presented in this thesis are tested experimentally on a one degree of freedom (1-DOF) system allowing the interaction with a person’s hand.After a 1st chapter presenting the state-of-the-art, the 2nd chapter tackles the identification methods developed in robotics as well as the issue of data filtering, analyzed both in simulation and experimentally. The question of the low-pass filter tuning is addressed, and in particular the choice of the cut-off frequency which remains delicate for a nonlinear system. To overcome these difficulties, a filtering technique using an extended Kalman filter (EKF) is developed from the robot dynamic model. The proposed EKF formulation allows a filter tuning depending on the known properties of the sensor and on the confidence on the initial parameters estimations. This method is compared in simulation and experimentally to different existing methods by analyzing its sensitivity to initialization and filter tuning. Results show that the proposed method is promising if the EKF is correctly tuned.The 3rd chapter concerns the continuous identification of the parameters of the model of a passive system interacting with a robotic system, by combining payload identification methods with online identification algorithms, without external sensors. These methods are validated in simulation and experimentally with the 1-DOF system whose handle is attached to elastic rubber bands to emulate a passive human joint. The analysis of the effects of the online methods tuning highlights a necessary trade-off between the convergence speed and the accuracy of the parameters estimates. Finally, the comparison of the payload identification methods shows that methods identifying separately the robotic system and the passive human parameters give better accuracy and a lower computation complexity.The 4th chapter deals with the identification during the human-robot interaction. A quadratic stiffness model is proposed to better fit the passive human joint behavior than a linear stiffness model. Then, this model is used with an iterative identification method based on outlier rejection technique, to detect the human user muscle activity without external sensors. This method is compared experimentally to a non-iterative method that uses electromyography (EMG), by adapting the 1-DOF system to interact with the wrist and to allow the detection of the flexor and extensor muscle activity of two human users. The proposed iterative identification method not using EMG signals achieves results close to those obtained with the non-iterative method using EMG signals when a model that correctly represents the passive human joint behavior is selected. The muscle activity detection results obtained with both methods show a satisfactory level of similarity compared to those obtained directly from EMG signals

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8

Chen, Jiaxiong. "Power System State Estimation Using Phasor Measurement Units". UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/35.

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State estimation is widely used as a tool to evaluate the real time power system prevailing conditions. State estimation algorithms could suffer divergence under stressed system conditions. This dissertation first investigates impacts of variations of load levels and topology errors on the convergence property of the commonly used weighted least square (WLS) state estimator. The influence of topology errors on the condition number of the gain matrix in the state estimator is also analyzed. The minimum singular value of gain matrix is proposed to measure the distance between the operating point and state estimation divergence. To study the impact of the load increment on the convergence property of WLS state estimator, two types of load increment are utilized: one is the load increment of all load buses, and the other is a single load increment. In addition, phasor measurement unit (PMU) measurements are applied in state estimation to verify if they could solve the divergence problem and improve state estimation accuracy. The dissertation investigates the impacts of variations of line power flow increment and topology errors on convergence property of the WLS state estimator. A simple 3-bus system and the IEEE 118-bus system are used as the test cases to verify the common rule. Furthermore, the simulation results show that adding PMU measurements could generally improve the robustness of state estimation. Two new approaches for improving the robustness of the state estimation with PMU measurements are proposed. One is the equality-constrained state estimation with PMU measurements, and the other is Hachtel's matrix state estimation with PMU measurements approach. The dissertation also proposed a new heuristic approach for optimal placement of phasor measurement units (PMUs) in power system for improving state estimation accuracy. In the problem of adding PMU measurements into the estimator, two methods are investigated. Method I is to mix PMU measurements with conventional measurements in the estimator, and method II is to add PMU measurements through a post-processing step. These two methods can achieve very similar state estimation results, but method II is a more time-efficient approach which does not modify the existing state estimation software.

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9

Ångman, Josefin, e Pernilla Larsson. "Remittances and Development : Empirical evidence from 99 developing countries". Thesis, Uppsala universitet, Nationalekonomiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-228416.

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Several studies have examined the effect of remittances on economic growth,poverty, education, and governance, among other factors, in developing countrieswith inconclusive results. Using annual panel data of 99 developing countries invarious empirical models, this study aim to answer the question how remittances affect a broader aspect of development using the Human Development Index asdependent variable. The findings indicate that there is a positive relationship between remittances and the level of human development in developing countries.

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10

Bai, Xiuqin. "Robust mixtures of regression models". Diss., Kansas State University, 2014. http://hdl.handle.net/2097/18683.

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Doctor of Philosophy
Department of Statistics
Kun Chen and Weixin Yao
This proposal contains two projects that are related to robust mixture models. In the robust project, we propose a new robust mixture of regression models (Bai et al., 2012). The existing methods for tting mixture regression models assume a normal distribution for error and then estimate the regression param- eters by the maximum likelihood estimate (MLE). In this project, we demonstrate that the MLE, like the least squares estimate, is sensitive to outliers and heavy-tailed error distributions. We propose a robust estimation procedure and an EM-type algorithm to estimate the mixture regression models. Using a Monte Carlo simulation study, we demonstrate that the proposed new estimation method is robust and works much better than the MLE when there are outliers or the error distribution has heavy tails. In addition, the proposed robust method works comparably to the MLE when there are no outliers and the error is normal. In the second project, we propose a new robust mixture of linear mixed-effects models. The traditional mixture model with multiple linear mixed effects, assuming Gaussian distribution for random and error parts, is sensitive to outliers. We will propose a mixture of multiple linear mixed t-distributions to robustify the estimation procedure. An EM algorithm is provided to and the MLE under the assumption of t- distributions for error terms and random mixed effects. Furthermore, we propose to adaptively choose the degrees of freedom for the t-distribution using profile likelihood. In the simulation study, we demonstrate that our proposed model works comparably to the traditional estimation method when there are no outliers and the errors and random mixed effects are normally distributed, but works much better if there are outliers or the distributions of the errors and random mixed effects have heavy tails.

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11

Palle, Sreeshailam. "Voltage Harmonic Control of Weak Utility Grid Through Distributed Energy Systems". University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1344998933.

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12

Anwar, Qaiser. "Optical Navigation by recognition of reference labels using 3D calibration of camera". Thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-18453.

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In this thesis a machine vision based indoor navigation system is presented. This is achieved by using rotationally independent optimized color reference labels and a geometrical camera calibration model which determines a set of camera parameters. All reference labels carry one byte of information (0 to 255), which can be designed for different values. An algorithm in Matlab has been developed so that a machine vision system for N number of symbols can recognize the symbols at different orientations. A camera calibration model describes the mapping between the 3-D world coordinates and the 2-D image coordinates. The reconstruction system uses the direct linear transform (DLT) method with a set of control reference labels in relation to the camera calibration. The least-squares adjustment method has been developed to calculate the parameters of the machine vision system. In these experiments it has been demonstrated that the pose of the camera can be calculated, with a relatively high precision, by using the least-squares estimation.

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13

Avan, Muhammet. "Joint Frequency Offset And Channel Estimation". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12610149/index.pdf.

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In this thesis study, joint frequency offset and channel estimation methods for single-input single-output (SISO) systems are examined. The performance of maximum likelihood estimate of the parameters are studied for different training sequences. Conventionally training sequences are designed solely for the channel estimation purpose. We present a numerical comparison of different training sequences for the joint estimation problem. The performance comparisons are made in terms of mean square estimation error (MSE) versus SNR and MSE versus the total training energy metrics. A novel estimation scheme using complementary sequences have been proposed and compared with existing schemes. The proposed scheme presents a lower estimation error than the others in almost all numerical simulations. The thesis also includes an extension for the joint channel-frequency offset estimation problem to the multi-input multi-output systems and a brief discussion for multiple frequency offset case is also given.

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14

Novanda, Happy. "Monitoring of power quality indices and assessment of signal distortions in wind farms". Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/monitoring-of-power-quality-indices-and-assessment-of-signal-distortions-in-wind-farms(403a470c-279a-4b00-94dc-eaa2507dc579).html.

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Power quality has become one of major concerns in the power industry. It can be described as the reliability of the electric power to maintain continuity operation of end-use equipment. Power quality problems are defined as deviation of voltage or current waveforms from the ideal value. The expansion plan of wind power generation has raised concern regarding how it influences the voltage and current signals. The variability nature of wind energy and the requirements of wind power generation increase the potential problems such as frequency and harmonic distortions. In order to analyze and mitigate problems in wind power generation, it is important to monitor power quality in wind farm. Therefore, the more accurate and reliable parameter estimation methods suitable for wind power generation are needed. Three parameter estimation methods are proposed in this thesis to estimate the unknown parameters, i.e. amplitude and phase angle of fundamental and harmonic components, DC component and system frequency, during the dynamic change in wind farm. In the first method, a self-tuning procedure is introduced to least square method to increase the immunity of the algorithm to noise. In the second method, nonrecursive Newton Type Algorithm is utilised to estimate the unknown parameters by obtaining the left pseudoinverse of Jacobian matrix. In the last technique, unscented transformation is used to replace the linearization procedure to obtain mean and covariance which will be used in Kalman filter method. All of the proposed methods have been tested rigorously using computer simulated data and have shown their capability to track the unknown parameters under extreme distortions. The performances of proposed methods have also been compared using real recorded data from several wind farms in Europe and have demonstrated high correlation. This comparison has verified that UKF requires the shortest processing time and STLS requires the longest.

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15

LEMECHA, MEGERSA ENDASHAW. "Microcredit and agricultural technology adoptions: evidence from ethiopia". Doctoral thesis, Università Politecnica delle Marche, 2021. http://hdl.handle.net/11566/290144.

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In Etiopia, le donne e le donne capofamiglia rappresentano una quota significativa delle famiglie agricole che sono anche estremamente povere. In questa tesi fornisco prove della necessità di andare oltre il microcredito e promuovere una più ampia inclusione finanziaria per influenzare la maggior parte delle strategie di sussistenza delle famiglie agricole, in particolare le adozioni tecnologiche. Uso un gruppo di famiglie ampio e rappresentativo a livello nazionale ottenuto dall'Etiopia rurale come parte dell'LSMS-ISA della Banca Mondiale a 1) comprendere i vincoli alle adozioni tecnologiche, evidenziando il credito 2) valutare se il microcredito è posizionato a lavorare per la maggior parte di loro. Per effetto di quest'ultimo, esamino le decisioni di partecipare ai mercati del credito e utilizzare un particolare tipo di credito; esplorare il rapporto tra prestatori formali e informali - se servono come sostituti o complementi. Gli ultimi due decenni hanno visto una drammatica espansione dell'accesso fisico al microcredito in ambienti agricoli poveri e rischiosi. Vi è una penetrazione limitata delle banche e molte famiglie, in particolare i piccoli agricoltori e gli agricoltori marginale si affidano a finanziamenti informali. Per molti, il microcredito viene introdotto per salvare i debitori poveri riducendo i vincoli di credito istituzionali e la loro dipendenza dalla finanza informale. Quindi ci si aspetta che la tecnologia dell'informazione e i meccanismi di esecuzione dei contratti dei prestatori di microcredito si trovino tra i due estremi. Mi avvalgo di metodologie econometriche all'avanguardia e complesse che consentono di ottenere risultati più affidabili e, di conseguenza, contributi più specifici alla ricerca e alla pratica.
In Ethiopia, women and female headed households make up significant share of farm households who are also extremely poor. In this thesis I provide evidence for the need to move beyond microcredit and promote a broader financial inclusion to affect a majority of farm households’ livelihood strategies, particularly technology adoptions. I use large and nationally representative panel of households obtained from rural Ethiopia as part of the World Bank’s LSMS-ISA to 1) understand constraints to technology adoptions, highlighting credit 2) assess whether microcredit is positioned to work for a majority of them. To the latter’s effect, I investigate decisions to participate in the credit markets and use a particular credit type; explore the relationship between formal and informal lenders - whether they serve as substitutes or complements. The last two decades has witnessed a dramatic expansion in the physical access to microcredit in poor, risky agrarian settings. There is limited penetration of banks and many households, especially small and marginal farmers rely on informal finance. For many, microcredit is introduced to rescue poor borrowers by reducing institutional credit constraints and their reliance on informal finance. So one expects that the information technology and contract enforcement mechanisms of microcredit lenders to lie between the two extremes. I employ state-of-the-art and complex econometric methodologies which allow to obtain more reliable results and, hence, more specific contributions to research and practice.

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16

BERNARDINI, EMMANUELA. "On the use of shrinkage estimators in macroeconometric modeling and forecasting". Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/207742.

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In the last years a growing °ow of information in the ¯eld of macroeconomy has been collected in very large databases. It is well known nevertheless that, when a large number of series is available standard statistical tools do not work well. This thesis proposes new estimators for high dimensional systems, that are an optimally weighted average of two already existing estimators, a traditional unbiased one, su®ering of a large estimation error, and a target one, having a lot of bias coming from a misspeci¯ed structural assumption, but little in terms of variance. This method is generally known as shrinkage. We derive two di®erent estimators connected with large dimensional systems. First a new estimator for the coe±cient matrix in a large dimensional vector autoregressive process (VAR) is proposed. It shows a better performance in forecasting macroeconomic time series than a set of existing estimators, including factor models and bayesian shrinkage estimators. A new estimator is also built for the variance covariance matrix in high dimensional systems. This new estimator is used to test for the presence of Serial Correlation Common Features (SCCF) in a multivariate setting involving many, noisy, and collinear time series. It shows a good performance in terms of empirical size if compared to the already existing tool of Canonical Correlation Analysis (CCA).
Negli ultimi anni un °usso crescente di informazione di carattere macroeconomico ¶e stato raccolto in ampi database. Tuttavia ¶e risaputo che, quando un gran numero di serie ¶e disponibile, gli strumenti statistici standard non forniscono risultati a±dabili. Questa tesi propone nuovi stimatori in sistemi di elevate dimensioni, che sono una media ottimamente ponderata di due stimatori gi¶a esistenti, uno stimatore tradizionale non distorto, che com- mette un grande errore di stima, e uno stimatore target, distorto a causa di un'assunzione strutturale sbagliata, ma con un basso errore di stima. Questo metodo ¶e conosciuto come shrinkage. Due stimatori di®erenti legati a sistemi di grandi dimensioni sono derivati. Per primo viene proposto un nuovo stimatore per la matrice dei coe±cienti in un modello autoregressivo vettoriale (VAR) di grandi dimensioni. Questo stimatore mostra una performance migliore nel prevedere serie storiche macroeconomiche rispetto a un set di stimatori gi¶a esistenti, tra i quali gli stimatori dei modelli fattoriali e gli stimatori shrinkage bayesiani. Viene anche costruito un nuovo stimatore per la matrice di varianza e covarianza in sistemi di grandi dimensioni. Questo nuovo stimatore ¶e usato per testare la presenza della carat- teristica comune della correlazione seriale canonica (SCCF) in un contesto multivariato che comprende molte serie storiche collineari. Questo stimatore mostra una buona performance, in termini di size empirica, se confrontato con il metodo gi¶a esistente della analisi della correlazione canonica (CCA).

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17

Liu, Tuo. "Model Selection and Adaptive Lasso Estimation of Spatial Models". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500379101560737.

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18

Klapil, Ondřej. "Fuzzy systémy s netradičními antecedenty fuzzy pravidel". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-220884.

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The aim of this work is to introduce a new type of fuzzy system AnYa. This system, unlike the classical fuzzy systems Takagi-Sugeno and Mamdani, uses a type of antecendent based on real data distribution. As part of the work there will be mentioned system programmed and its functionality will be verified on testing data.

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19

Karagozlu, Eren. "A Study On Symbol Synchronization And Channel Estimation Form-ary Orthogonal Transmission". Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613622/index.pdf.

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In this thesis, two key issues regarding M-ary orthogonal signaling systems, namely channel estimation and symbol timing recovery are investigated. Kasami codes, which are also called quasi orthogonal codes, are used for transmission of the information in place of orthogonal waveforms. In order to achieve symbol synchronization, a timing recovery scheme based on the Maximum Likelihood (ML) estimation of timing offset is proposed and the effects of proposed structure over the receiver performance are examined by using computer simulations. Moreover, the receiver performance of M-ary orthogonal signals transmitted over multipath fading channel is investigated. Least Square (LS) approach, based on the transmission of known training sequence, is used to estimate the channel impulse response. In addition to this, frame synchronization is employed at the receiver to extract the timing information by determining the start time of the received symbols. Computer simulations related to the proposed receiver structure are carried out in order to observe how the system performance is affected under multipath fading channel. Parameter selection guides regarding a good performance are also provided.

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20

Yapici, Yavuz. "A Bidirectional Lms Algorithm For Estimation Of Fast Time-varying Channels". Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613220/index.pdf.

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Effort to estimate unknown time-varying channels as a part of high-speed mobile communication systems is of interest especially for next-generation wireless systems. The high computational complexity of the optimal Wiener estimator usually makes its use impractical in fast time-varying channels. As a powerful candidate, the adaptive least mean squares (LMS) algorithm offers a computationally efficient solution with its simple first-order weight-vector update equation. However, the performance of the LMS algorithm deteriorates in time-varying channels as a result of the eigenvalue disparity, i.e., spread, of the input correlation matrix in such chan nels. In this work, we incorporate the L MS algorithm into the well-known bidirectional processing idea to produce an extension called the bidirectional LMS. This algorithm is shown to be robust to the adverse effects of time-varying channels such as large eigenvalue spread. The associated tracking performance is observed to be very close to that of the optimal Wiener filter in many cases and the bidirectional LMS algorithm is therefore referred to as near-optimal. The computational complexity is observed to increase by the bidirectional employment of the LMS algorithm, but nevertheless is significantly lower than that of the optimal Wiener filter. The tracking behavior of the bidirectional LMS algorithm is also analyzed and eventually a steady-state step-size dependent mean square error (MSE) expression is derived for single antenna flat-fading channels with various correlation properties. The aforementioned analysis is then generalized to include single-antenna frequency-selective channels where the so-called ind ependence assumption is no more applicable due to the channel memory at hand, and then to multi-antenna flat-fading channels. The optimal selection of the step-size values is also presented using the results of the MSE analysis. The numerical evaluations show a very good match between the theoretical and the experimental results under various scenarios. The tracking analysis of the bidirectional LMS algorithm is believed to be novel in the sense that although there are several works in the literature on the bidirectional estimation, none of them provides a theoretical analysis on the underlying estimators. An iterative channel estimation scheme is also presented as a more realistic application for each of the estimation algorithms and the channel models under consideration. As a result, the bidirectional LMS algorithm is observed to be very successful for this real-life application with its increased but still practical level of complexity, the near-optimal tracking performa nce and robustness to the imperfect initialization.

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21

Feng, Dehua. "Determining Intersection Turning Movements with Detection Errors". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1512746695445707.

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22

Zhu, Guoliang. "Trajectory-aided GNSS land navigation : application to train positioning". Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0007/document.

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Au cours des dernières années, la technologie GNSS a attiré beaucoup d’attention autour du monde et elle a été largement appliquée dans de nombreux domaines. D'autre part, le système d'exploitation ferroviaire avancé a été largement utilisé pour assurer la sécurité, la sûreté et l'efficacité du réseau ferroviaire. L'efficacité de ce système se fonde sur la disponibilité du positionnement fiable du train. L’application de cette technologie au positionnement du train est un domaine de recherche très prometteur. Dans cette thèse, plusieurs algorithmes sont proposés pour le positionnement du train en utilisant des signaux GNSS et un modèle géométrique de voie stocké dans la base de données à bord du train. Premièrement, la distance, vitesse du train sont estimées en utilisant des signaux GNSS et un modèle géométrique ‘idéal’ qui est composé de lignes droites, de courbes de transition et d'arcs de cercle. L’impact du rayon de courbure de la voie sur ces estimations est étudié. Deuxièmement, la distance, vitesse du train sont estimées en utilisant des signaux GNSS et un modèle géométrique ‘non-idéal’ qui est approché par une ligne polygonale avec un certain niveau d'incertitude. L’impact de l’incertitude de la voie sur ces estimations est étudié. Finalement, la distance, vitesse du train sont estimées à l’aide d’intégration des mesures GNSS et une base de données bruitée. L’impact des erreurs de GNSS et de la base de données sur ces estimations est étudié
Over these years, GNSS technology has attracted many attentions around world and it has been widely applied in navigation for airplanes, ground vehicles and boats. On the other hand, advanced railway operating systems have been widely used to guarantee the safety and efficiency of the railway network. The efficiency of these systems is based on the availability of reliable train positioning. Hence, applying GNSS technology to the train positioning is a very promising research area, since it has such important benefits as lower initial costs and lower maintenance. In this thesis, several algorithms are proposed for train positioning by using GNSS signals and the railway centerline stored in the onboard computer database. At first, the train travelled distance, speed are estimated by using GNSS signals and an ''ideal'' railway centerline which is composed of straight line segments, transition curves and arcs of circles. The impact of the railroad curvature on these estimations is studied. Secondly, the train travelled distance, speed are estimated by using GNSS signals and a ''non-ideal'' railway centerline which is defined by a polygonal line with some level of uncertainty. The impact of the track geometric model imprecision on these estimations is studied. Finally, the train travelled distance, speed are estimated by integrating the GNSS measurements with a track database. The impact of the GNSS measurements and the track database errors on these estimations is studied

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Meng, Rui Daniel. "Design and implementation of sensor fusion for the towed synthetic aperture sonar". Thesis, University of Canterbury. Electrical and Computer Engineering, 2007. http://hdl.handle.net/10092/1199.

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For synthetic aperture imaging, position and orientation deviation is of great concern. Unknown motions of a Synthetic Aperture Sonar (SAS) can blur the reconstructed images and degrade image quality considerably. Considering the high sensitivity of synthetic aperture imaging technique to sonar deviation, this research aims at providing a thorough navigation solution for a free-towed synthetic aperture sonar (SAS) comprising aspects from the design and construction of the navigation card through to data postprocessing to produce position, velocity, and attitude information of the sonar. The sensor configuration of the designed navigation card is low-cost Micro-Electro-Mechanical-Systems (MEMS) Magnetic, Angular Rate, and Gravity (MARG) sensors including three angular rate gyroscopes, three dual-axial accelerometers, and a triaxial magnetic hybrid. These MARG sensors are mounted orthogonally on a standard 180mm Eurocard PCB to monitor the motions of the sonar in six degrees of freedom. Sensor calibration algorithms are presented for each individual sensor according to its characteristics to precisely determine sensor parameters. The nonlinear least square method and two-step estimator are particularly used for the calibration of accelerometers and magnetometers. A quaternion-based extended Kalman filter is developed based on a total state space model to fuse the calibrated navigation data. In the model, the frame transformations are described using quaternions instead of other attitude representations. The simulations and experimental results are demonstrated in this thesis to verify the capability of the sensor fusion strategy.

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Iurinic, Leonardo Ulises. "Localização de faltas de alta impedância em sistemas de distribuição de energia : uma abordagem baseada na estimação de parâmetros associados a modelos no domínio do tempo". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/141940.

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A detecção de um tipo particular de falta, denominado de alta impedância, tem sido há muito tempo um desafio para a engenharia de proteção. Por outro lado, se a detecção é realizada com sucesso, ações preventivas e de manutenção devem ser tomadas para evitar prejuízos potenciais. Nesse contexto, os métodos de localização de faltas assumem importante papel, pois contribuem para a rápida restauração do sistema. Entretanto, os métodos clássicos, em particular as formulações a um terminal, não consideram modelos realísticos de faltas de alta impedância na sua formulação. Este tipo de falta se caracteriza pelo contato de um condutor energizado com uma superfície de elevada resistência elétrica, em que o comportamento da tensão em função da corrente apresenta uma característica não linear. Desta forma, esta tese propõe uma nova formulação para a localização de faltas de alta impedância em sistemas de distribuição de energia elétrica, com medições a um terminal, que considere tal efeito. A formulação é proposta para estimar a distância da falta em linhas de distribuição utilizando o método de estimação por mínimos quadrados, desenvolvendo um modelo no domínio do tempo do sistema elétrico e um modelo de falta de alta impedância composto por diodos antiparalelos. Mediante o modelo do sistema elétrico, é possível estimar a distância da falta, juntamente com os parâmetros da falta de alta impedância, usando sinais provenientes de um terminal, como um problema de otimização. Primeiramente, não considerando o efeito capacitivo das linhas, um modelo linear no domínio do tempo é obtido e um estimador de mínimos quadrados linear é proposto. Posteriormente, considerando o efeito capacitivo das linhas, um modelo não linear no domínio do tempo é obtido e um algoritmo de descida é proposto para a estimação dos parâmetros. Os estudos de caso foram realizados no sistema de 13 barras da IEEE modelado no Alternative Transient Program. Em todas as condições simuladas, os resultados obtidos mostraram um desempenho similar da técnica proposta com ou sem a consideração da capacitância das linhas, sendo assim, por simplicidade, optou-se pela desconsideração da capacitância. Os resultados evidenciaram que a técnica de localização de faltas proposta não mostra diferença no seu desempenho com variações do ângulo de incidência da falta e melhora quando o carregamento do sistema diminui. O erro relacionado à estimativa da distância da falta mostra-se, em geral, superior ao erro cometido ao estimar os parâmetros da falta de alta impedância. Por outro lado, os estudos de caso mostram um grande potencial para aplicar a técnica proposta como um detector e classificador de faltas de alta impedância.
High impedance fault location has always been a challenge for protection engineering. On the other hand, if this task is successfully realized maintenance action could be performed in order to avoid potential injuries. For an effective protection scheme the high impedance fault location should be performed, but a lack of research on this area is noted. This thesis proposes a new analytical formulation for high impedance fault location in power systems. The approach is developed in time domain, considering a high impedance fault model composed by two antiparallel diodes. Using this model, the fault distance and fault parameters are estimated as a minimization problem, allowing the location of the fault using one terminal signals. Firstly, the line capacitance is not considered and a linear model in time domain is obtained. In this case, the linear least square estimator is used for parameter estimation. In a second moment, the line capacitance is considered and a non-linear model in time domain is obtained. Hence, a steepest descent based estimator is proposed in order to estimate the parameters. Studies were carried out with the IEEE 13 bus modeled in the Alternative Transient Program. In view of the test results, the non-consideration of line capacitance resulted in similar accuracy in relation to its consideration. The method also is insensitive to the fault inception instant and the reduction of system load reduces the errors related to the estimations. The error related to fault distance estimation is in general greater than the estimation of the high impedance fault parameters. On the other hand, case studies shows the great potential of the technique as a high impedance fault detector method.

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Dam, Long H. "Applied Mass Properties Identification Method to the Cal Poly's Spacecraft Simulator". DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1175.

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The Cal Poly Spacecraft Simulator is currently being developed for future testing and verifying theoretical control applications. This paper details the effort to balance the platform and remove undesired external torque from the system using System Identification technique developed by Patrick Healy. Since the relationship between the input and output of the system is linear, the least square method is proposed to identify the mass properties and location of center of mass of the system. The tests use four sine wave generators that are out of phase with different amplitudes as the inputs to excite various structural modes of the system. The outputs, angular rates of the platform, are measured by the newly implemented LN-200 Inertial Measurement Unit that helps reducing the measurement noise. Two test cases of 90o yaw rotations with the identified inertia were performed and validated against the computer simulation model; and the result shows that the test cases trajectories followed closely with the computer simulation model.

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Thomas, Robin Rajan. "Optimisation of adaptive localisation techniques for cognitive radio". Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/27076.

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Spectrum, environment and location awareness are key characteristics of cognitive radio (CR). Knowledge of a user’s location as well as the surrounding environment type may enhance various CR tasks, such as spectrum sensing, dynamic channel allocation and interference management. This dissertation deals with the optimisation of adaptive localisation techniques for CR. The first part entails the development and evaluation of an efficient bandwidth determination (BD) model, which is a key component of the cognitive positioning system. This bandwidth efficiency is achieved using the Cramer-Rao lower bound derivations for a single-input-multiple-output (SIMO) antenna scheme. The performances of the single-input-single-output (SISO) and SIMO BD models are compared using three different generalised environmental models, viz. rural, urban and suburban areas. In the case of all three scenarios, the results reveal a marked improvement in the bandwidth efficiency for a SIMO antenna positioning scheme, especially for the 1×3 urban case, where a 62% root mean square error (RMSE) improvement over the SISO system is observed. The second part of the dissertation involves the presentation of a multiband time-of arrival (TOA) positioning technique for CR. The RMSE positional accuracy is evaluated using a fixed and dynamic bandwidth availability model. In the case of the fixed bandwidth availability model, the multiband TOA positioning model is initially evaluated using the two-step maximum-likelihood (TSML) location estimation algorithm for a scenario where line-of-sight represents the dominant signal path. Thereafter, a more realistic dynamic bandwidth availability model has been proposed, which is based on data obtained from an ultra-high frequency spectrum occupancy measurement campaign. The RMSE performance is then verified using the non-linear least squares, linear least squares and TSML location estimation techniques, using five different bandwidths. The proposed multiband positioning model performs well in poor signal-to-noise ratio conditions (-10 dB to 0 dB) when compared to a single band TOA system. These results indicate the advantage of opportunistic TOA location estimation in a CR environment.
Dissertation (MEng)--University of Pretoria, 2012.
Electrical, Electronic and Computer Engineering
unrestricted

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27

Ondra, Václav. "Vytvoření aplikace pro získání modálních parametrů při experimentální modální analýze". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231415.

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The aim of this diploma thesis is a creation of modal parameter estimation application. Modal properties (natural frequencies, damping factors and mode shapes) are used in many dynamics analysis and their accurate determination is very important therefore the modal parameter estimation is one of the most significant part of the experimental modal analysis. Many methods have been developed for modal parameter estimation, each of them with different assumptions and with different accuracy. In the beginning of this thesis, a theory connected with modal analysis and a theory which is necessary for understanding to presented modal parameter methods are given. Then four different modal parameter estimation methods are presented - Peak Picking, Circle Fit, Least Square method and Eigensystem Realization Algorithm. The application for the modal parameter estimation is the output of this diploma thesis. In addition, the application allows performing all experimental modal analysis such as estimation of frequency response functions, animation of the found mode shapes, different kinds of comparison etc. In the conclusion, three structures are shown on which the application and modal parameter estimation methods were tested.

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Barbosa, Davis Pereira. "Estudo de técnicas de otimização para reconstrução de energia de jatos no primeiro nível de seleção de eventos do experimento ATLAS". Universidade Federal de Juiz de Fora (UFJF), 2012. https://repositorio.ufjf.br/jspui/handle/ufjf/5476.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Atualmente, o LHC é o maior e mais energético colisionador de partículas em fun-cionamento, colidindo prótons com energias de 7 TeV no centro de massa a cada 50 ns. Vários detectores estão posicionados para medir as características das partículas após a colisão, sendo então utilizadas para verificar a validade das novas teorias de física de partículas. O ATLAS é o maior dos detectores do LHC, estando em operação desde 2009 e fornecendo uma grande quantidade de dados para as análise físicas para a busca do Higgs. Um dos principais responsáveis pelas qualidade das informações adquiridas pelo ATLAS é o seu sistema de seleção de eventos online que foi desenvolvido para rejeitar informações irrelevantes das colisões, excluindo a enorme quantidade de ruído de fundo do experimento. Entretanto, o LHC passará por atualizações visando o au-mento da sua luminosidade em uma ordem de grandeza (103' para 1035) nos próximos dez anos, gerando assim uma maior quantidade de eventos por colisão, aumentando a probabilidade de empilhamento de eventos. Desta forma, o ATLAS e o seu sistema de seleção de eventos online também deverão sofrer modificações para atender aos novos requisitos do experimento. O presente trabalho realizou estudos sobre a utilização de novos algoritmos para estimação da energia de jatos no primeiro nível de seleção de eventos do detector ATLAS. Inicialmente, uma janela bidimensional é aplicada na região onde o jato foi identificado, visando a redução do impacto do empilhamento dos eventos nas bordas desta região. Em seguida, é proposta a utilização da informação de profundidade do calorímetro hadrônico do ATLAS na estimação de energia do jato, através de técnicas de otimização linear (mínimos quadrados) e não-linear (redes neu-rais artificiais). Os resultados obtidos, através de simulações Monte Carlo, mostraram que a informação de profundidade do TileCal reduz o erro de estimação da energia dos jatos em aproximadamente 23%, enquanto que a utilização da janela bidimen-sional melhora o comportamento inicial da curva de acionamento de jatos indicando sua efetividade em cenários de empilhamento de eventos.
The LHC is the biggest and most energetic particle collider, performing proton-proton collisions with 7 TeV on center of mass at 50 ns rate. Several detectors are placed along the LHC in order to measure the collisions results, envisaging the validation or rejection of the new particle physics theories. The ATLAS experiment is the biggest detector at LHC, operating very well since 2009 and providing large amount of data for the physics analysis envisaging the search for the Higgs Particle. The online event selection system (trigger) is one of the major reponsibles for the quality of the acquired data in ATLAS, it was designed to reject the huge amount of background noise generated at LHC. However, the LHC upgrade for high luminosity (10' to 1035) in the following ten years will increase the amount of events per collison, increasing the event pileup probability. In order to cope with the new luminosity requirements, the ATLAS and its trigger system will also upgrade its components and algorithms. This work presents the studies about the use of new algorithms for jet energy estimation in the first level of the ATLAS trigger system. Envisaging the reduction of the pileup effect, a bidimensional window is applied on the region where the event was identified (RoI). Additionally, the longitudinal information from the ATLAS hadronic calorimeter (TileCal) is used in order to improve the jet energy estimation, using linear (Least Square) and nonlinear (Artificial Neural Networks) optimization techniques. The achieved results, through Monte Carlo simulations, show that the TileCal logitudinal information reduces the energy estimation error by 23%, while the bidimensional window slightly improves the jet turn on curve indicating the reduction of the pileup effects.

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Destino, G. (Giuseppe). "Positioning in wireless networks:non-cooperative and cooperative algorithms". Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789514299742.

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Abstract In the last few years, location-awareness has emerged as a key technology for the future development of mobile, ad hoc and sensor networks. Thanks to location information, several network optimization strategies as well as services can be developed. However, the problem of determining accurate location, i.e. positioning, is still a challenge and robust algorithms are yet to be developed. In this thesis, we focus on the development of distance-based non-cooperative and cooperative algorithms, which is derived based on a non-parametric non- Bayesian framework, specifically with a Weighted Least Square (WLS) optimization. From a theoretic perspective, we study the WLS problem and establish the optimality through the relationship with a Maximum Likelihood (ML) estimator. We investigate the fundamental limits and derive the consistency conditions by creating a connection between Euclidean geometry and inference theory. Furthermore, we derive the closed-form expression of a distance-model based Cramér-Rao Lower Bound (CRLB), as well as the formulas, that characterize information coupling in the Fisher information matrix. Non-cooperative positioning is addressed as follows. We propose a novel framework, namely the Distance Contraction, to develop robust non-cooperative positioning techniques. We prove that distance contraction can mitigate the global minimum problem and structured distance contraction yields nearly optimal performance in severe channel conditions. Based on these results, we show how classic algorithms such as the Weighted Centroid (WC) and the Non-Linear Least Square (NLS) can be modified to cope with biased ranging. For cooperative positioning, we derive a novel, low complexity and nearly optimal global optimization algorithm, namely the Range-Global Distance Continuation method, to use in centralized and distributed positioning schemes. We propose an effective weighting strategy to cope with biased measurements, which consists of a dispersion weight that captures the effect of noise while maximizing the diversity of the information, and a geometric-based penalty weight, that penalizes the assumption of bias-free measurements. Finally, we show the results of a positioning test where we employ the proposed algorithms and utilize commercial Ultra-Wideband (UWB) devices
Tiivistelmä Viime vuosina paikkatietoisuudesta on tullut eräs merkittävä avainteknologia mobiili- ja sensoriverkkojen tulevaisuuden kehitykselle. Paikkatieto mahdollistaa useiden verkko-optimointistrategioiden sekä palveluiden kehittämisen. Kuitenkin tarkan paikkatiedon määrittäminen, esimerkiksi kohteen koordinaattien, on edelleen vaativa tehtävä ja robustit algoritmit vaativat kehittämistä. Tässä väitöskirjassa keskitytään etäisyyspohjaisten, yhteistoiminnallisten sekä ei-yhteistoiminnallisten, algoritmien kehittämiseen. Algoritmit pohjautuvat parametrittömään ei-bayesilaiseen viitekehykseen, erityisesti painotetun pienimmän neliösumman (WLS) optimointimenetelmään. Väitöskirjassa tutkitaan WLS ongelmaa teoreettisesti ja osoitetaan sen optimaalisuus todeksi tarkastelemalla sen suhdetta suurimman todennäköisyyden (ML) estimaattoriin. Lisäksi tässä työssä tutkitaan perustavanlaatuisia raja-arvoja sekä johdetaan yhtäpitävyysehdot luomalla yhteys euklidisen geometrian ja inferenssiteorian välille. Väitöskirjassa myös johdetaan suljettu ilmaisu etäisyyspohjaiselle Cramér-Rao -alarajalle (CRLB) sekä esitetään yhtälöt, jotka karakterisoivat informaation liittämisen Fisherin informaatiomatriisiin. Väitöskirjassa ehdotetaan uutta viitekehystä, nimeltään etäisyyden supistaminen, robustin ei-yhteistoiminnallisen paikannustekniikan perustaksi. Tässä työssä todistetaan, että etäisyyden supistaminen pienentää globaali minimi -ongelmaa ja jäsennetty etäisyyden supistaminen johtaa lähes optimaaliseen suorituskykyyn vaikeissa radiokanavan olosuhteissa. Näiden tulosten pohjalta väitöskirjassa esitetään, kuinka klassiset algoritmit, kuten painotetun keskipisteen (WC) sekä epälineaarinen pienimmän neliösumman (NLS) menetelmät, voidaan muokata ottamaan huomioon etäisyysmittauksen harha. Yhteistoiminnalliseksi paikannusmenetelmäksi johdetaan uusi, lähes optimaalinen algoritmi, joka on kompleksisuudeltaan matala. Algoritmi on etäisyyspohjainen globaalin optimoinnin menetelmä ja sitä käytetään keskitetyissä ja hajautetuissa paikannusjärjestelmissä. Lisäksi tässä työssä ehdotetaan tehokasta painotusstrategiaa ottamaan huomioon mittausharha. Strategia pitää sisällään dispersiopainon, joka tallentaa häiriön aiheuttaman vaikutuksen maksimoiden samalla informaation hajonnan, sekä geometrisen sakkokertoimen, joka rankaisee harhattomuuden ennakko-oletuksesta. Lopuksi väitöskirjassa esitetään tulokset kokeellisista mittauksista, joissa ehdotettuja algoritmeja käytettiin kaupallisissa erittäin laajakaistaisissa (UWB) laitteissa

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Stringhini, Mário. "AJUSTAMENTO E CONTROLES DE QUALIDADE DAS LINHAS POLIGONAIS". Universidade Federal de Santa Maria, 2005. http://repositorio.ufsm.br/handle/1/9524.

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Brazil is a country of great dimension that still holds unexplored areas of little population nowadays. Actually these lands are state-owned, but they have been appropriated as a private property, especially in the Amazon basin. The need for a governmental more effective territorial management was formally implemented through the establishment of a geodetic referenced landed property register. This system will integrate the public administration organization and the land register services in a common basis of data. The geodetic science and the advanced technological resources like the Global Positioning System, which receives radio rays transmitted by satellites that surround the Earth and the electronic tachymeter, which capture light rays reflected on locations over the surface of the Earth, enable reliable geodetic references for the database graphic. Brazilian government takes into consideration the set of a wide basis of data in 10 years in order to control the undue appropriation of lands in the agricultural border, as well as great management over the territorial organization in the states of consolidated agrarian structure. The present work has been thought with the purpose of improving topographic survey quality by means of adjustment and quality survey estimation to serve geodetic referencing principles. This survey of a 9-points traverse being used one control point. It was implanted at Federal University of Santa Maria campus with electronic tachymeter and the obtained data worked in a digital calculation form. The qui-square test of the quadratic form of misclosures was put into practice to evaluate the survey as a whole. Then the adjustment by the least square method was done, utilizing the observation equations taken from the variation of coordinates. The weight unit variance a posteriori was calculated in the qui-square test in the quadratic form of the residuals, which evaluates adjustment quality. The variance-covariance matrix of the adjusted coordinates have enable the estimation for point of the trasverse by using the calculation of the geometric parameters of the standard error ellipse, error ellipse, mean squared position error or radial error and circular error probable. Also, data snooping test of Baarda was developed to identify the observations that could present measuring problems. All the procedures were organized in a diagram to make a computer programming easier. In that research, instrumental systematic errors were verified, but they did not impair the method presentation. The adjustment has shown convergence after little iterations, the qui-square tests were in the range of acceptance of the hypotheses; the data snooping test has shown the most reliable observations while the estimations for point were quantified and graphically presented. The author hopes the work contributes to offer an accessible alternative scientifically based to surveyors, under the new paradigm presented by Topography.
O Brasil é um país de grande dimensão que ainda hoje possui vastas áreas virgens de pouca população e possuidoras de terras tidas como devolutas, especialmente na bacia amazônica. A necessidade de um gerenciamento territorial mais efetivo por parte do Estado foi implementada via burocrática com a criação de um cadastro nacional de imóveis rurais georreferenciados, sistema que integrará os órgãos públicos da administração direta e os serviços registrais de terras em uma base comum de dados. A ciência geodésica e os recursos tecnológicos avançados como o Sistema de Posicionamento Global que recebem sinais de rádio de atélites que circundam a Terra e os taquímetros eletrônicos que captam sinais infravermelho refletidos em locações sobre a superfície da Terra possibilitam levantamentos com georreferencias confiáveis para o banco de dados gráfico. O Estado Brasileiro considera que em 10 anos terá uma base de dados abrangente para controlar a apropriação indevida de terras na fronteira agrícola, bem como grande gerência sobre o ordenamento do território nos estados de estrutura agrária consolidada. O presente trabalho foi pensado com o objetivo de agregar valor aos levantamentos topográficos com o uso do ajustamento e de estimativas de qualidade de levantamentos visando atender os preceitos do georrefenciamento. O levantamento de um polígono de 9 (nove) vértices, sendo um usado como ponto de controle, foi implantado no campus da Universidade Federal de Santa Maria com taquímetro eletrônico e os dados obtidos trabalhados em uma planilha de cálculo digital. O teste qui-quadrado da forma quadrática do erro de fechamento foi aplicado para avaliação do levantamento como um todo. A seguir foi praticado o ajustamento pelo método dos mínimos quadrados, com o emprego de equações de observação obtidas por variação de coordenadas. A variância da unidade peso a posteriori foi calculada no teste qui-quadrado da forma quadrática dos resíduos que avalia a qualidade do ajustamento. A matriz de variância-covariância das coordenadas ajustadas possibilitou a estimação por ponto da poligonal com o cálculo dos parâmetros das figuras geométricas das elipses dos erros e de confiança e dos círculos do erro de posição e do erro médio. Também o teste data snooping de Baarda foi aplicado para identificação das observações que poderiam apresentar problemas de medições. Todos os procedimentos foram organizados em um fluxograma de forma a facilitar uma programação computacional. No trabalho desenvolvido foram constatados erros sistemáticos instrumentais, que não prejudicaram a apresentação do método. O ajustamento mostrou convergência após poucas iterações, os testes qui-quadrados ficaram na região de aceitação das hipóteses, o teste data snooping mostrou as observações mais confiáveis enquanto que as estimações por ponto foram quantificadas e apresentadas graficamente. O autor espera que a obra contribua para oferecer uma alternativa acessível e fundamentada cientificamente aos profissionais em seus levantamentos, sob o novo paradigma vivido pela Topografia.

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31

Barbosa, Daniel. "Estimação da freqüência em sistemas elétricos de potência através de filtragem adaptativa". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-11092007-155259/.

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Abstract (sommario):

Este trabalho apresenta um método para a estimação da freqüência em sistemas elétricos de potência utilizando filtros adaptativos baseados no algoritmo dos mínimos quadrados (LMS - least mean square). A análise do sistema de potência é realizada através da conversão das tensões trifásicas em um sinal complexo pela aplicação da transformada \'alfa\'\'beta\', cuja forma complexa foi direcionada ao algoritmo de filtragem adaptativa. O método é baseado na aplicação da filtragem adaptativa para a realização de rastreio do sinal de entrada, o que permite verificar o seu comportamento variante no tempo. O algoritmo proposto foi testado através de formas de ondas geradas com o software Matlab e de simulações realizadas através do software Alternative Transients Program (ATP). É importante salientar que nas simulações do ATP foram modelados diversos equipamentos que constituem o sistema elétrico de potência, incluindo um gerador síncrono com regulação de velocidade, linhas de transmissão com variação em freqüência e transformadores de potência com suas respectivas curvas de saturação. Estas modelagens tiveram por objetivo gerar dados das mais diversas e distintas situações para a verificação e análise da metodologia proposta. Os resultados da pesquisa mostram a excelência na aplicabilidade do algoritmo proposto na estimação da freqüência de um sistema elétrico, mesmo com sinais ruidosos, além do rastreio fiel da freqüência em situações de manobra e operação. Alguns dos resultados apresentados comparam as estimações obtidas pela técnica proposta em relação às estimações de um determinado relé comercial, habilitado à supervisão da freqüência.
This work presents a method for frequency estimation in power systems using adaptive filters based in the algorithm of least mean square (LMS). The analysis of the power system is made through the conversion of the three-phase voltages in a complex signal with the application of \'alfa\'\'beta\' transform, whose complex form was directed to the algorithm of adaptive filtering. The method is based on the application of the adaptive filtering for tracking the input signal, and it allows verifying its variant behavior in time. The algorithm was tested through waveforms generated by Matlab software and simulations carried out through Alternative Transients Program (ATP) software. It is important to point out that in the simulations using ATP many diferent power system equipments had been modeled, including a synchronous generator with speed regulation, transmission lines with variation in frequency and power transformers with their saturation curves. The objective of these tests was to generate data for diverse and distinct situations for the verification and the analysis of the proposed methodology. The results of the research show the excellence in the applicability of the algorithm considered in frequency estimation of an electrical system, even with noisy signals, as well as the tracking of the frequency during operation. Some of the results are compared to the ones presented by a commercial relay set to track frequency.

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32

Glickman, Mark. "Disturbance monitoring in distributed power systems". Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/16497/1/Mark_Glickman_Thesis.pdf.

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Power system generators are interconnected in a distributed network to allow sharing of power. If one of the generators cannot meet the power demand, spare power is diverted from neighbouring generators. However, this approach also allows for propagation of electric disturbances. An oscillation arising from a disturbance at a given generator site will affect the normal operation of neighbouring generators and might cause them to fail. Hours of production time will be lost in the time it takes to restart the power plant. If the disturbance is detected early, appropriate control measures can be applied to ensure system stability. The aim of this study is to improve existing algorithms that estimate the oscillation parameters from acquired generator data to detect potentially dangerous power system disturbances. When disturbances occur in power systems (due to load changes or faults), damped oscillations (or "modes") are created. Modes which are heavily damped die out quickly and pose no threat to system stability. Lightly damped modes, by contrast, die out slowly and are more problematic. Of more concern still are "negatively damped" modes which grow exponentially with time and can ultimately cause the power system to fail. Widespread blackouts are then possible. To avert power system failures it is necessary to monitor the damping of the oscillating modes. This thesis proposes a number of damping estimation algorithms for this task. If the damping is found to be very small or even negative, then additional damping needs to be introduced via appropriate control strategies. This thesis presents a number of new algorithms for estimating the damping of modal oscillations in power systems. The first of these algorithms uses multiple orthogonal sliding windows along with least-squares techniques to estimate the modal damping. This algorithm produces results which are superior to those of earlier sliding window algorithms (that use only one pair of sliding windows to estimate the damping). The second algorithm uses a different modification of the standard sliding window damping estimation algorithm - the algorithm exploits the fact that the Signal to Noise Ratio (SNR) within the Fourier transform of practical power system signals is typically constant across a wide frequency range. Accordingly, damping estimates are obtained at a range of frequencies and then averaged. The third algorithm applied to power system analysis is based on optimal estimation theory. It is computationally efficient and gives optimal accuracy, at least for modes which are well separated in frequency.

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33

Glickman, Mark. "Disturbance monitoring in distributed power systems". Queensland University of Technology, 2007. http://eprints.qut.edu.au/16497/.

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Abstract (sommario):

Power system generators are interconnected in a distributed network to allow sharing of power. If one of the generators cannot meet the power demand, spare power is diverted from neighbouring generators. However, this approach also allows for propagation of electric disturbances. An oscillation arising from a disturbance at a given generator site will affect the normal operation of neighbouring generators and might cause them to fail. Hours of production time will be lost in the time it takes to restart the power plant. If the disturbance is detected early, appropriate control measures can be applied to ensure system stability. The aim of this study is to improve existing algorithms that estimate the oscillation parameters from acquired generator data to detect potentially dangerous power system disturbances. When disturbances occur in power systems (due to load changes or faults), damped oscillations (or "modes") are created. Modes which are heavily damped die out quickly and pose no threat to system stability. Lightly damped modes, by contrast, die out slowly and are more problematic. Of more concern still are "negatively damped" modes which grow exponentially with time and can ultimately cause the power system to fail. Widespread blackouts are then possible. To avert power system failures it is necessary to monitor the damping of the oscillating modes. This thesis proposes a number of damping estimation algorithms for this task. If the damping is found to be very small or even negative, then additional damping needs to be introduced via appropriate control strategies. This thesis presents a number of new algorithms for estimating the damping of modal oscillations in power systems. The first of these algorithms uses multiple orthogonal sliding windows along with least-squares techniques to estimate the modal damping. This algorithm produces results which are superior to those of earlier sliding window algorithms (that use only one pair of sliding windows to estimate the damping). The second algorithm uses a different modification of the standard sliding window damping estimation algorithm - the algorithm exploits the fact that the Signal to Noise Ratio (SNR) within the Fourier transform of practical power system signals is typically constant across a wide frequency range. Accordingly, damping estimates are obtained at a range of frequencies and then averaged. The third algorithm applied to power system analysis is based on optimal estimation theory. It is computationally efficient and gives optimal accuracy, at least for modes which are well separated in frequency.

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34

Benedito, Raphael Augusto de Souza. "Índice de não-detecção de erros grosseiros no processo de estimação de estado em sistemas elétricos de potência". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-21072011-100837/.

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A partir de uma análise geométrica, do estimador de estado por mínimos quadrados ponderados, propõe-se, neste trabalho, um índice para classificação das medidas de acordo com as suas características de não refletirem grande parcela de seus erros nos resíduos do processo de estimação de estado, por mínimos quadrados ponderados. O índice proposto foi denominado Índice de Não-Detecção de Erros, ou apenas UI (Undetectability Index). As medidas com maiores UI são aquelas cujos erros grosseiros (EGs) são mais difíceis de serem detectados através de métodos que fazem uso da análise dos resíduos. Isto porque os erros dessas medidas são, de certa forma, \"mascarados\", isto é, não são refletidos nos resíduos das mesmas. Nesse sentido, a medida crítica é o caso limite de medidas cujos erros são mascarados, isto é, possui UI infinito e seu resíduo é igual a zero, independente de a mesma ter ou não EG. Para obtenção dos índices UI das medidas, desenvolveu-se um algoritmo simples e de fácil implementação. Tomando por base o índice UI, propõe-se, também, uma metodologia para processamento de EGs e dois algoritmos para projeto ou fortalecimento de sistemas de medição. Esses algoritmos possibilitam a obtenção de sistemas de medição confiáveis (observáveis e isentos de medidas críticas e de conjuntos críticas de medidas), de baixo custo e formados por medidas com índices UI menores que um valor pré-estabelecido. Para validar o índice UI e as suas aplicações propostas neste trabalho, realizaram-se diversas simulações computacionais nos sistemas de 14 e 30 barras do IEEE, tendo sido satisfatórios todos os resultados obtidos.
The present thesis proposes an index, called Undetectability Index (UI), to classify the measurements according to their characteristics of not reflecting their errors into the residuals of the weighted least squares state estimation process from a geometric analysis of this estimator. Gross errors in measurements with higher UIs are very difficult to be detected by methods based on the residual analysis, as the errors in those measurements are \"masked\", i.e., they are not reflected in the residuals. In this sense, critical measurements are the limit case of measurements that mask errors, that is, they have infinite UI and their residuals are always zero independently of their having or not gross errors. Based on the UI a methodology for gross error processing and two algorithms for metering system planning are also proposed in this thesis. These algorithms enable the obtaining of reliable measurement systems (observable and free from critical measurements and critical sets of measurements) with low investment and containing only measurements with UIs lower than a pre-established value. Several simulation results (with IEEE 14-bus and 30-bus systems) have validated the UI and its application.

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35

Ramalho, Guilherme Matiussi. "Uma abordagem estatística para o modelo do preço spot da energia elétrica no submercado sudeste/centro-oeste brasileiro". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-26122014-145848/.

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O objetivo deste trabalho e o desenvolvimento de uma ferramenta estatistica que sirva de base para o estudo do preco spot da energia eletrica do subsistema Sudeste/Centro-Oeste do Sistema Interligado Nacional, utilizando a estimacao por regressao linear e teste de razao de verossimilhanca como instrumentos para desenvolvimento e avaliacao dos modelos. Na analise dos resultados estatsticos descritivos dos modelos, diferentemente do que e observado na literatura, a primeira conclusao e a verificacao de que as variaveis sazonais, quando analisadas isoladamente, apresentam resultados pouco aderentes ao preco spot PLD. Apos a analise da componente sazonal e verificada a influencia da energia fornecida e a energia demandada como variaveis de entrada, com o qual conclui-se que especificamente a energia armazenada e producao de energia termeletrica sao as variaveis que mais influenciam os precos spot no subsistema estudado. Entre os modelos testados, o que particularmente ofereceu os melhores resultados foi um modelo misto criado a partir da escolha das melhores variaveis de entrada dos modelos testados preliminarmente, alcancando um coeficiente de determinacao R2 de 0.825, resultado esse que pode ser considerado aderente ao preco spot. No ultimo capitulo e apresentada uma introducao ao modelo de predicao do preco spot, possibilitando dessa forma a analise do comportamento do preco a partir da alteracao das variaveis de entrada.
The objective of this work is the development of a statistical method to study the spot prices of the electrical energy of the Southeast/Middle-West (SE-CO) subsystem of the The Brazilian National Connected System, using the Least Squares Estimation and Likelihood Ratio Test as tools to perform and evaluate the models. Verifying the descriptive statistical results of the models, differently from what is observed in the literature, the first observation is that the seasonal component, when analyzed alone, presented results loosely adherent to the spot price PLD. It is then evaluated the influence of the energy supply and the energy demand as input variables, verifying that specifically the stored water and the thermoelectric power production are the variables that the most influence the spot prices in the studied subsystem. Among the models, the one that offered the best result was a mixed model created from the selection of the best input variables of the preliminarily tested models, achieving a coeficient of determination R2 of 0.825, a result that can be considered adherent to the spot price. At the last part of the work It is presented an introduction to the spot price prediction model, allowing the analysis of the price behavior by the changing of the input variables.

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36

Zadeh, Ramin Agha. "Performance control of distributed generation using digital estimation of signal parameters". Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/47011/1/Ramin_Agha_Zadeh_Thesis.pdf.

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The Queensland University of Technology (QUT) allows the presentation of a thesis for the Degree of Doctor of Philosophy in the format of published or submitted papers, where such papers have been published, accepted or submitted during the period of candidature. This thesis is composed of seven published/submitted papers, of which one has been published, three accepted for publication and the other three are under review. This project is financially supported by an Australian Research Council (ARC) Discovery Grant with the aim of proposing strategies for the performance control of Distributed Generation (DG) system with digital estimation of power system signal parameters. Distributed Generation (DG) has been recently introduced as a new concept for the generation of power and the enhancement of conventionally produced electricity. Global warming issue calls for renewable energy resources in electricity production. Distributed generation based on solar energy (photovoltaic and solar thermal), wind, biomass, mini-hydro along with use of fuel cell and micro turbine will gain substantial momentum in the near future. Technically, DG can be a viable solution for the issue of the integration of renewable or non-conventional energy resources. Basically, DG sources can be connected to local power system through power electronic devices, i.e. inverters or ac-ac converters. The interconnection of DG systems to power system as a compensator or a power source with high quality performance is the main aim of this study. Source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, distortion at the point of common coupling in weak source cases, source current power factor, and synchronism of generated currents or voltages are the issues of concern. The interconnection of DG sources shall be carried out by using power electronics switching devices that inject high frequency components rather than the desired current. Also, noise and harmonic distortions can impact the performance of the control strategies. To be able to mitigate the negative effect of high frequency and harmonic as well as noise distortion to achieve satisfactory performance of DG systems, new methods of signal parameter estimation have been proposed in this thesis. These methods are based on processing the digital samples of power system signals. Thus, proposing advanced techniques for the digital estimation of signal parameters and methods for the generation of DG reference currents using the estimates provided is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1. One of the main parameters of a power system signal is its frequency. Phasor Measurement (PM) technique is one of the renowned and advanced techniques used for the estimation of power system frequency. Chapter 2 focuses on an in-depth analysis conducted on the PM technique to reveal its strengths and drawbacks. The analysis will be followed by a new technique proposed to enhance the speed of the PM technique while the input signal is free of even-order harmonics. The other techniques proposed in this thesis as the novel ones will be compared with the PM technique comprehensively studied in Chapter 2. An algorithm based on the concept of Kalman filtering is proposed in Chapter 3. The algorithm is intended to estimate signal parameters like amplitude, frequency and phase angle in the online mode. The Kalman filter is modified to operate on the output signal of a Finite Impulse Response (FIR) filter designed by a plain summation. The frequency estimation unit is independent from the Kalman filter and uses the samples refined by the FIR filter. The frequency estimated is given to the Kalman filter to be used in building the transition matrices. The initial settings for the modified Kalman filter are obtained through a trial and error exercise. Another algorithm again based on the concept of Kalman filtering is proposed in Chapter 4 for the estimation of signal parameters. The Kalman filter is also modified to operate on the output signal of the same FIR filter explained above. Nevertheless, the frequency estimation unit, unlike the one proposed in Chapter 3, is not segregated and it interacts with the Kalman filter. The frequency estimated is given to the Kalman filter and other parameters such as the amplitudes and phase angles estimated by the Kalman filter is taken to the frequency estimation unit. Chapter 5 proposes another algorithm based on the concept of Kalman filtering. This time, the state parameters are obtained through matrix arrangements where the noise level is reduced on the sample vector. The purified state vector is used to obtain a new measurement vector for a basic Kalman filter applied. The Kalman filter used has similar structure to a basic Kalman filter except the initial settings are computed through an extensive math-work with regards to the matrix arrangement utilized. Chapter 6 proposes another algorithm based on the concept of Kalman filtering similar to that of Chapter 3. However, this time the initial settings required for the better performance of the modified Kalman filter are calculated instead of being guessed by trial and error exercises. The simulations results for the parameters of signal estimated are enhanced due to the correct settings applied. Moreover, an enhanced Least Error Square (LES) technique is proposed to take on the estimation when a critical transient is detected in the input signal. In fact, some large, sudden changes in the parameters of the signal at these critical transients are not very well tracked by Kalman filtering. However, the proposed LES technique is found to be much faster in tracking these changes. Therefore, an appropriate combination of the LES and modified Kalman filtering is proposed in Chapter 6. Also, this time the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 7 proposes the other algorithm based on the concept of Kalman filtering similar to those of Chapter 3 and 6. However, this time an optimal digital filter is designed instead of the simple summation FIR filter. New initial settings for the modified Kalman filter are calculated based on the coefficients of the digital filter applied. Also, the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 8 uses the estimation algorithm proposed in Chapter 7 for the interconnection scheme of a DG to power network. Robust estimates of the signal amplitudes and phase angles obtained by the estimation approach are used in the reference generation of the compensation scheme. Several simulation tests provided in this chapter show that the proposed scheme can very well handle the source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, and synchronism of generated currents or voltages. The purposed compensation scheme also prevents distortion in voltage at the point of common coupling in weak source cases, balances the source currents, and makes the supply side power factor a desired value.

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Frémondière, Pierre. "L'évolution de l'accouchement dans la lignée humaine. Estimation de la contrainte fœto-pelvienne par deux méthodes complémentaires : la simulation numérique de l'accouchement et l'analyse discriminante des modalités d'accouchement au sein d'un échantillon obstétrical". Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM5013.

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Notre objectif est d’étudier les modalités d’accouchement au sein de la lignée humaine. Pour cela, nous utilisons deux approches complémentaires : la simulation numérique de l’accouchement et l’analyse discriminante des modalités d’accouchement au sein d’un échantillon obstétrical. Dans un premier temps, nous construisons des maillages de bassins et de crânes de foetus fossiles grâce à une méthode d’interpolation : le krigeage. Les groupes fossiles considérés sont les Australopithèques, les premiers représentants du genre Homo (PRGH) et les représentants du genre Homo au Pléistocène moyen et supérieur (RPMS). Les dimensions des crânes juvéniles sont utilisées pour estimer « à rebours » les dimensions néonatales à l’aide de courbes de croissance humaine et de chimpanzé. Nous réalisons une simulation numérique de l’accouchement à partir des maillages de ces dyades « virtuelles ». Puis nous réalisons des analyses discriminantes avec un jeu de données issu de mesures réalisées sur le pelviscanner de femmes et sur les mesures du crâne de leur nouveau-né afin de séparer les modalités d’accouchement grâce aux variables foeto-pelviennes. Ces mêmes variables foeto-pelviennes sont mesurées chez les dyades fossiles afin d’identifier, par les analyses discriminantes, leurs modalités d’accouchement les plus probables. Nos résultats suggèrent un accouchement eutocique sans rotation intra-pelvienne chez les Australopithèques, eutocique avec rotation intrapelvienne chez les PRGH, dystocique ou eutocique chez les RPMS, l’accouchement eutocique est caractérisé par une rotation et une incurvation de la trajectoire de descente
The purpose of this thesis is to estimate delivery outcomes for extinct hominids. We therefore use two complementary methods : numerical simulation of childbirth and discriminant analysis of delivery outcomes from an obstetrical sample. First, we use kriging to construct meshes of pelves and neonatal skulls. Fossil hominid specimens included in the study are Australopithecines, early Homo (EH) and middle to early Pleistocene Homo (MEPH). We estimate fetal cranial dimensions with chimpanzee or human cranial growth curve that we reversly use and apply on juveniles skull measurements. “Virtual” dyads are formed from pelves and neonatal skulls. Then, we simulate childbirth of these « virtual » dyads. Different levels of laxity of the sacro-iliac junction and different positions of the fetal head are considered. Finally, we use an obstetrical sample: delivery outcome is noted, CT-scans are used to obtain maternal pelvic measurements and diameters of the fetal head were also measured after delivery. A discriminant analysis is performed using this obstetrical sample to separate delivery outcomes thanks to fetal-pelvic measurements. Fossil dyads were subsequently added in the discriminant analysis to assess delivery outcomes to which they belong. Results suggest small fetal-pelvic constraint for Austalopithecines. This constraint is moderate for EH. Fetal-pelvic constraint is more important for MEPH. We suggest that rotational birth appears with EH. The curved trajectory of the fetal head appears with MEPH. Emergence of rotational birth and curved trajectory of fetal head are probably explained by two major increases in brain size during late and middle Pleistocene

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Hassani, Mujtaba. "CONSTRUCTION EQUIPMENT FUEL CONSUMPTION DURING IDLING : Characterization using multivariate data analysis at Volvo CE". Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-49007.

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Human activities have increased the concentration of CO2 into the atmosphere, thus it has caused global warming. Construction equipment are semi-stationary machines and spend at least 30% of its life time during idling. The majority of the construction equipment is diesel powered and emits toxic emission into the environment. In this work, the idling will be investigated through adopting several statistical regressions models to quantify the fuel consumption of construction equipment during idling. The regression models which are studied in this work: Multivariate Linear Regression (ML-R), Support Vector Machine Regression (SVM-R), Gaussian Process regression (GP-R), Artificial Neural Network (ANN), Partial Least Square Regression (PLS-R) and Principal Components Regression (PC-R). Findings show that pre-processing has a significant impact on the goodness of the prediction of the explanatory data analysis in this field. Moreover, through mean centering and application of the max-min scaling feature, the accuracy of models increased remarkably. ANN and GP-R had the highest accuracy (99%), PLS-R was the third accurate model (98% accuracy), ML-R was the fourth-best model (97% accuracy), SVM-R was the fifth-best (73% accuracy) and the lowest accuracy was recorded for PC-R (83% accuracy). The second part of this project estimated the CO2 emission based on the fuel used and by adopting the NONROAD2008 model. Keywords:

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39

Kahaei, Mohammad Hossein. "Performance analysis of adaptive lattice filters for FM signals and alpha-stable processes". Thesis, Queensland University of Technology, 1998. https://eprints.qut.edu.au/36044/7/36044_Digitised_Thesis.pdf.

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The performance of an adaptive filter may be studied through the behaviour of the optimal and adaptive coefficients in a given environment. This thesis investigates the performance of finite impulse response adaptive lattice filters for two classes of input signals: (a) frequency modulated signals with polynomial phases of order p in complex Gaussian white noise (as nonstationary signals), and (b) the impulsive autoregressive processes with alpha-stable distributions (as non-Gaussian signals). Initially, an overview is given for linear prediction and adaptive filtering. The convergence and tracking properties of the stochastic gradient algorithms are discussed for stationary and nonstationary input signals. It is explained that the stochastic gradient lattice algorithm has many advantages over the least-mean square algorithm. Some of these advantages are having a modular structure, easy-guaranteed stability, less sensitivity to the eigenvalue spread of the input autocorrelation matrix, and easy quantization of filter coefficients (normally called reflection coefficients). We then characterize the performance of the stochastic gradient lattice algorithm for the frequency modulated signals through the optimal and adaptive lattice reflection coefficients. This is a difficult task due to the nonlinear dependence of the adaptive reflection coefficients on the preceding stages and the input signal. To ease the derivations, we assume that reflection coefficients of each stage are independent of the inputs to that stage. Then the optimal lattice filter is derived for the frequency modulated signals. This is performed by computing the optimal values of residual errors, reflection coefficients, and recovery errors. Next, we show the tracking behaviour of adaptive reflection coefficients for frequency modulated signals. This is carried out by computing the tracking model of these coefficients for the stochastic gradient lattice algorithm in average. The second-order convergence of the adaptive coefficients is investigated by modeling the theoretical asymptotic variance of the gradient noise at each stage. The accuracy of the analytical results is verified by computer simulations. Using the previous analytical results, we show a new property, the polynomial order reducing property of adaptive lattice filters. This property may be used to reduce the order of the polynomial phase of input frequency modulated signals. Considering two examples, we show how this property may be used in processing frequency modulated signals. In the first example, a detection procedure in carried out on a frequency modulated signal with a second-order polynomial phase in complex Gaussian white noise. We showed that using this technique a better probability of detection is obtained for the reduced-order phase signals compared to that of the traditional energy detector. Also, it is empirically shown that the distribution of the gradient noise in the first adaptive reflection coefficients approximates the Gaussian law. In the second example, the instantaneous frequency of the same observed signal is estimated. We show that by using this technique a lower mean square error is achieved for the estimated frequencies at high signal-to-noise ratios in comparison to that of the adaptive line enhancer. The performance of adaptive lattice filters is then investigated for the second type of input signals, i.e., impulsive autoregressive processes with alpha-stable distributions . The concept of alpha-stable distributions is first introduced. We discuss that the stochastic gradient algorithm which performs desirable results for finite variance input signals (like frequency modulated signals in noise) does not perform a fast convergence for infinite variance stable processes (due to using the minimum mean-square error criterion). To deal with such problems, the concept of minimum dispersion criterion, fractional lower order moments, and recently-developed algorithms for stable processes are introduced. We then study the possibility of using the lattice structure for impulsive stable processes. Accordingly, two new algorithms including the least-mean P-norm lattice algorithm and its normalized version are proposed for lattice filters based on the fractional lower order moments. Simulation results show that using the proposed algorithms, faster convergence speeds are achieved for parameters estimation of autoregressive stable processes with low to moderate degrees of impulsiveness in comparison to many other algorithms. Also, we discuss the effect of impulsiveness of stable processes on generating some misalignment between the estimated parameters and the true values. Due to the infinite variance of stable processes, the performance of the proposed algorithms is only investigated using extensive computer simulations.

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40

XIONG, CHANG-WANG, e 熊長旺. "VLSI design for least mean square estimator". Thesis, 1991. http://ndltd.ncl.edu.tw/handle/19707947165589732000.

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41

Yee, Lim Wei, e 林暐詒. "Ordered Iterative Least Square Estimator for Extended Efficiency Model". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2tfwuq.

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42

CHIEH, CHUANG MENG, e 莊孟傑. "Implementation of direction of arrival estimator on least square-root algorithm". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/20455068487410183933.

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43

Lu, Hong Kee, e 呂宏基. "Design and Implementation of Acoustic Direction-of-Arrival Estimator on Least Square-Root Algorithm". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/14019028709605791942.

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碩士
國立海洋大學
電機工程學系
88
The application of sensor array processing technique become vastly. Many researchers put efforts to improve the resolution and estimate the exact parameter. In common, all reference just discussed in a computer simulation under an algorithm neglecting the real world exist problem. In this thesis, we will concentrate on the implementation of the algorithm of DOA estimation with the stretch of hardware structure in the underwater acoustic. We utilize the TMS320C32 Digital Signal Processing development produced by the Texas Instrument as the core and estimate the DOA the of signal by using Least Square-Root algorithm. Finally, to develop a suit of complete DOA system that can be operated independently. During the program development, we use assembly language to implement the mathematical operation of DOA algorithm. Moreover, it is not only can detect noncoherent signal but also can process coherent signal, such as detecting the DOA in multipath environments underwater.

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44

Cheng, Hsin-Yi, e 鄭欣怡. "Least Square Estimation for Monotone Regression". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/54891074921282633358.

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碩士
淡江大學
數學學系碩士班
97
Search for a simple, smooth and efficient estimate of a smooth monotone regression function is of considerable interest. In this thesis, we describe a least square method for monotone regression in which the regression function is modeled by the Bernstein polynomial. We employ the cross-validation criterion to determine the degree of Bernstein polynomial, propose a penalty function method based algorithm to compute estimate and provide a pointwise confidence band for regression function. The success of this method is demonstrated in simulation studies and in an analysis of real data.

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45

Wijayanti, Lovina, e 劉飛那. "Proton Energy Estimation by Least Square Method". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/63hj38.

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碩士
國立中央大學
物理學系
105
Proton therapy has become one of the most promising radiation techniques for nowadays cancer treatment. A special dose characteristic of proton called as Bragg peak has contributed to spare the dose for normal tissues surrounding cancer. In order to obtain the benefit of Bragg peak, a well-known physics calculation model is needed by treatment planning system to calculate proton dose distribution before it is delivered to the patient. Monte Carlo simulation code is the most used code for the proton simulation. However, different Monte Carlo codes, such as GEANT4, FLUKA, MCNP6, give different approaches when they are used to simulate the passage of protons through the material. Therefore, a proton multiple scattering experiment at Research Center for Nuclear Physics (RCNP), Osaka University has been conducted to verify the agreement between simulation and experimental data. One of the aims in RCNP experiment was to measure the remaining proton kinetic energy by using the Range Finder. For this reason, in this simulation study, the Range Finder was used to estimate the incident proton energy by Least Square method. The Least Square method has been applied to estimate a 160 MeV and 60 – 78 MeV incident proton one-by-one. This method was found to provide ~ 1 MeV accuracy when it used to estimate a 160 MeV incident proton and ~ 0.5 MeV accuracy when it used to estimate the 60 – 78 MeV incident proton. This result shows that Least Square is an effective method for estimating incident proton energy. Furthermore, from a clinical application point of view, the Least Square method has also been applied to estimate 63 – 65 MeV monoenergetic proton planar beam source and it was found to provide ~ 0.2 MeV accuracy. This result implies that in the future, the LS method may be used to improve the proton beam energy measurement for such a low proton energy, especially to treat ocular cancer which usually needs the proton with an incident energy of 63.5 MeV.

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46

"The generalized least square estimation of polychoric correlation". Chinese University of Hong Kong, 1985. http://library.cuhk.edu.hk/record=b5885574.

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47

Wei, Tzu-Hsuan, e 魏子軒. "Weighted Least Square Methods for MaterialAbundance Estimation in Hyperspectral Image". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/60623984756782539802.

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碩士
國立中央大學
資訊工程研究所
93
Recently, hyperspectral images are widely used for target detection in remotely sensed imagery. They take advantage of hundreds of contiguous spectral channels to uncover materials that usually cannot be resolved by multispectal images. However, the ground resolution in hyperspectral imagery is generally larger than the size of targets of interest, under this circumstance target detection must be carried out at subpixel level. Linear spectral mixture analysis (LSMA) is a widely used technique for subpixel target detection and material classification in hyperspectral image, and least squares unmixing methods are widely used to solve linear mixture problems for material abundance estimation. In this thesis, a weighted least squares (WLS) method is introduced as a generalization. When different weight matrix is applied, a certain detector or classifier will be resulted. Several previous proposed methods have been proven to be versions of WLS methods. For accurate abundance fraction estimation, a fully constrained weighted least squares (FCWLS) approach is developed by combining sum-to-one and nonnegativity constraints. In order to further apply the designed algorithm to unknown image scenes, an unsupervised least squares method is also proposed. Furthermore, several noise estimation methods are introduced, and we also compare the performance of target detection capability. A serious of computer simulation and real hyperspectral image experiments were conducted in this thesis. The experimental results showed that the noise whitening least squares method in target detection and FCWLS approach in abundance fraction estimation have better performance.

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48

Ching-Liue, Kuo, e 郭慶略. "Global Motion Estimation and Compensation: Using Recursive Least Square Method". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/10472329708973155581.

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碩士
義守大學
資訊工程學系
90
Motion compensation method compresses a digital video sequence by removing temporal redundancy between frames. It predicts the current frame based on the previous frame and the motion information between the two frames. Moving objects cause local intensities changes whereas the changes due to the motion of camera are global. Since the global motion would increase the number of moving blocks, many approaches for eliminating the global motion have been developed recently. This thesis presents an efficient method to estimate global motion parameters. We use an affine model to represent the global motion and develop a recursive least square scheme to speed up the estimate of motion parameters. In addition, in the proposed method the motion vectors in the background area are selected for the estimate of affine parameters, which improves the estimate reliability. The simulation results indicate that the proposal method improves both computational efficiency and estimation accuracy, as compared to the iterative least square method.

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49

Shih, Po Hsun, e 施伯勳. "Channel Estimation by Least-Square Algorithm for DVB-T system". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/25h4m6.

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碩士
長庚大學
電機工程學系
104
In this paper, we discussed in digital video broadcasting (DVB-T) system. Consider two cases: (1) only the scattered pilot; and (2) scattered pilot plus continuous pilot. We will discuss their differences in LS channel estimation method under the time-variant channel. If the maximum channel delay is large, there is a nearly singular matrix problem when a receiver adopts the frequency domain LS (FDLS) method to estimate the data subcarrier channel frequency response. This problem renders FDLS channel estimation more sensitive to noise. We will discuss difference modified parameter, in order to solve the problem of singular matrix in the LS estimation method.

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50

Tandan, G. Roshan. "Detection of Large Signal Disturbances by Least Square Estimation Technique". Thesis, 2016. http://ethesis.nitrkl.ac.in/9339/1/2016_MT_GRTandan.pdf.

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In power system, there are several factors which can cause severe disturbance in the system, like fault occurrence, over loading etc. These faults need to be detected and rectified in minimal time to get the system in steady state. In this project, our aim was to detect all those large disturbances present in the system which can cause instability and malfunction of the power system. For these we have performed dynamic simulation of the IEEE 9 bus system and then the stream of voltage magnitudes obtained during dynamic simulation are used to get the best estimated value and by the help of least square estimation technique the disturbance are detected whether it is large disturbance or small disturbance. For these we first have performed the steady state analysis of given IEEE 9 bus system by Newton Raphson’s method and then we have done the dynamic simulation of given IEEE 9 bus system and solved the swing equations in two different cases first for no fault in the system and second by considering a 3 phase symmetrical fault in the system by Modified Euler’s method. By these we get the voltage profile for each buses and with the help of these voltage profile the detection of large signal disturbance has been done by the least square estimation technique and we got the simulation result on the basis of that we can observe the presence of large disturbances in the system.

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Tesi sul tema "Least-Square estimator"

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