Nonparametric procedures use weak assumptions such as continuity of the distribution so that they are applicable to a large class F of underlying distributions. Statistics that are distribution-free over F may be constructed to be estimators of location. Such estimators are derived from rank tests called R-estimators. They are robust estimators. The concept of robust estimation is based on a neighborhood of parametric models called "gross error models". The M-estimator, which is a maximum likelihood type estimator, arose from such investigations using the normal distribution. A third big class of estimators is the class of linear combinations of order statistics called L-estimators. They are constructed as an average of quantiles. Examples are the sample mean and the sample median.In this thesis, some definitions and results involving these three basic classes of estimates are provided. For each class, an example of a robust estimator is presented. Numerical values are given to assess the robustness of each estimator in terms of breakdown point and gross error sensitivity. Further, the U-statistics which are unbiased estimators of location parameters, are used to obtain asymptotically efficient R-estimates. / Department of Mathematical Sciences

In this thesis, a new method based on characteristic functions is proposed to estimate the jump component in a finite-activity Levy process, which includes the jump frequency and the jump size distribution. Properties of the estimators are investigated, which show that this method does not require high frequency data. The implementation of the method is discussed, and examples are provided. We also perform a comparison which shows that our method has advantages over an existing threshold method. Finally, two applications are included: one is the classification of the increments of the model, and the other is the testing for a change of jump frequency.

This thesis considers the Simultaneous Localization and Mapping (SLAM) problem using a set of perspective cameras arranged such that there is no overlap in their fields-of-view. With the known and fixed extrinsic calibration of each camera within the cluster, a novel real-time pose estimation system is presented that is able to accurately track the motion of a camera cluster relative to an unknown target object or environment and concurrently generate a model of the structure, using only image-space measurements. A new parameterization for point feature position using a spherical coordinate update is presented which isolates system parameters dependent on global scale, allowing the shape parameters of the system to converge despite the scale parameters remaining uncertain. Furthermore, a flexible initialization scheme is proposed which allows the optimization to converge accurately using only the measurements from the cameras at the first time step. An analysis is presented identifying the configurations of the cluster motions and target structure geometry for which the optimization solution becomes degenerate and the global scale is ambiguous. Results are presented that not only confirm the previously known critical motions for a two-camera cluster, but also provide a complete description of the degeneracies related to the point feature constellations. The proposed algorithms are implemented and verified in experiments with a camera cluster constructed using multiple perspective cameras mounted on a quadrotor vehicle and augmented with tracking markers to collect high-precision ground-truth motion measurements from an optical indoor positioning system. The accuracy and performance of the proposed pose estimation system are confirmed for various motion profiles in both indoor and challenging outdoor environments.

An existing drivetrain model with clutch temperature dynamics has been used to simulate the behaviour of a heavy duty truck. During the implementation of the model in MATLAB/Simulink modularity and simplicity was greatly emphasized. This was done in order to facilitate the use of the model in various applications as well as making it easy to understand. The main contributions of the thesis is however the adaptation of a clutch temperature and wear observer for use in an on-line application in the gearbox management system (GMS). The process of taking the observer from an off-line simulation environment to running on-line includes taking into consideration the configuration and limitations of the GMS as well as adapting the interface of the observer. Concretely this means dealing with the limitations of the available data types in the GMS, compensating for the effect of biased measurements as well as accounting for the different dynamics of the sensor-types used in the clutch.In a simulation environment the performance of the adapted observer has been studied and its ability to compensate for heat expansion and wear in the clutch shown. / En existerande drivlinemodell med temperaturdynamik i kopplingen har använts för att simulera beteendet hos en lastbil. Vid implementation av modellen i MATLAB/Simulink betonades vikten av en enkel och modulär struktur. Detta gjordes för att underlätta användning av modellen i olika applikationer samt för att göra den lätt att förstå.De huvudsakliga bidragen i uppsatsen är anpassningen av en temperatur- och slitageobeservatör på kopplingen för användning i realtid av växellådans styrenhet. För att ta observatören från simulerings- till realtidsmiljö måste styrenhetens konfiguration och begränsningar beaktas samt gränssnittet hos observatören anpassas. Konkret betyder detta att hänsyn till begränsningarna hos de olika datatyper som används i kopplingens styrenhet tagits, att den negativa inverkan som brusiga mätsignaler kan få begränsats samt att skillnader i dynamik hos de olika sensortyper som används i kopplingen kompenserats för. Med simuleringar har prestandan hos den anpassade observatören studerats samt dess förmåga att kompensera för värmeutvidgning och slitage i kopplingen visats.

Most microbial activity in nature takes place at interfaces where redox discontinuities are present. Organic pollutants in groundwater encounter oxic/anoxic interfaces when they emerge to surface water bodies or volatilize above the plume. Such oxic/anoxic interfaces are key habitats for aerobic bacteria and are in turn created by the bacteria that degrade organic electron donors. In the absence of biodegradation, synthetic pollutants can migrate from the plume and impact a variety of receptors. The aims of our study were to determine whether microbes at oxic/anoxic interfaces can use synthetic chemicals as electron donors and protect the overlying vadose zone or surface water from groundwater pollutants. The approach was to design columns representing the interfaces and measure activities of the microbial communities responsible for the biodegradation of synthetic compounds.Taken together the above studies established clearly that contaminants recalcitrant under anaerobic conditions but degradable under aerobic conditions can be biodegraded at the narrow oxic/anoxic interface resulting in the protection of the overlying soil or water. The findings provide the basis for new approaches to natural attenuation that can serve to dramatically reduce the cost of bioremediation actions. Synthetic chemicals are widespread in the environment because of their extensive use in industry. These chemicals were recalcitrant until their microbial degradation pathways evolved. Currently the biodegradation pathways of many synthetic chemicals are known and serve as the basis for bioremediation strategies. The second part of the research described here involved discovery of the aerobic degradation pathway of a dye additive: 4-nitroaniline (4NA). Annotation of the whole genome sequence coupled with assays and supported with cloned enzymes revealed that the 4NA biodegradation pathway contains two monooxygenase steps prior to ring cleavage. Because nitroaniline degradation was not previously understood our work advanced the understanding of metabolic diversity in degradation of amino and nitro compounds by providing enzymes with unique activities.

Array signal processing is an important branch in the field of signal processing. In recent years, it has developed dramatically. It can be applied in such fields as radio detection and ranging, communication, sonar, earthquake, exploration, astronomy and biomedicine. The field of direction of array signal processing can be classified into self-adaption array signal processing and spatial spectrum, in which spatial spectrum estimation theory and technology is still in the ascendant status, and become a main aspect in the course of array signal processing. Spatial spectrum estimation is focused on investigating the system of spatial multiple sensor arrays, with the main purpose of estimating the signal’s spatial parameters and the location of the signal source. The spatial spectrum expresses signal distribution in the space from all directions to the receiver. Hence, if one can get the signal’s spatial spectrum, then the direction of arrival (DOA) can be obtained. As thus, spatial spectrum estimation is also called DOA estimation. DOA technology research is important in array signal processing, which is an interdisciplinary technology that develops rapidly in recent years, especially the direction of arrival with multiple signal sources, the estimation of coherent signal sources, and the DOA estimation of broadband signals. DOA estimation has a wide application prospect in radar, sonar, communication, seismology measurement and biomedicine. Over the past few years, all kinds of algorithms which can be used in DOA estimation have made great achievements, the most classic algorithm among which is Multiple Signal Classification (MUSIC). In this thesis I will give an overview of the DOA estimation based on MUSIC algorithm.

Due to the large influx of computers in our daily lives, human-computer interaction has become crucially important. For a long time, focusing on what users need has been critical for designing interaction methods. However, new perspective tends to extend this attitude to encompass how human desires, interests, and ambitions can be met and supported. This implies that the way we interact with computers should be revisited. Centralizing human values rather than user needs is of the utmost importance for providing new interaction techniques. These values drive our decisions and actions, and are essential to what makes us human. This motivated us to introduce new interaction methods that will support human values, particularly human well-being. The aim of this thesis is to design new interaction methods that will empower human to have a healthy, intuitive, and pleasurable interaction with tomorrow’s digital world. In order to achieve this aim, this research is concerned with developing theories and techniques for exploring interaction methods beyond keyboard and mouse, utilizing human body. Therefore, this thesis addresses a very fundamental problem, human motion analysis. Technical contributions of this thesis introduce computer vision-based, marker-less systems to estimate and analyze body motion. The main focus of this research work is on head and hand motion analysis due to the fact that they are the most frequently used body parts for interacting with computers. This thesis gives an insight into the technical challenges and provides new perspectives and robust techniques for solving the problem.

Many minimum distance estimators have the potential to provide parameter estimates which are both robust and efficient and yet, despite these highly desirable theoretical properties, they are rarely used in practice. This is because the performance of these estimators is rarely guaranteed per se but obtained by placing a suitable value on some tuning parameter. Hence there is a risk involved in implementing these methods because if the value chosen for the tuning parameter is inappropriate for the data to which the method is applied, the resulting estimators may not have the desired theoretical properties and could even perform less well than one of the simpler, more widely used alternatives. There are currently no data-based methods available for deciding what value one should place on these tuning parameters hence the primary aim of this research is to develop an objective way of selecting values for the tuning parameters in minimum distance estimators so that the full potential of these estimators might be realised. This new method was initially developed to optimise the performance of the density power divergence estimator, which was proposed by Basu, Harris, Hjort and Jones [3]. The results were very promising so the method was then applied to two other minimum distance estimators and the results compared.

CanX-4/-5 is a formation flying technology demonstration mission that shall demonstrate sub-meter formation tracking control. The key to this precision control is carrier phase differential GPS state estimation, which enables centimeter-level relative state estimation. In this thesis, the formation flying controller design is reviewed in detail, and an innovative closed-loop formation reconfiguration strategy is presented. In addition, the designs of both coarse- and fine-mode relative state estimators are presented. Formation flying simulations demonstrate the efficacy of the proposed control and coarse estimation. Furthermore, hardware tests are performed to test the computational efficiency of the control algorithms and to validate the fine-mode relative navigation filter.

CanX-4/-5 is a formation flying technology demonstration mission that shall demonstrate sub-meter formation tracking control. The key to this precision control is carrier phase differential GPS state estimation, which enables centimeter-level relative state estimation. In this thesis, the formation flying controller design is reviewed in detail, and an innovative closed-loop formation reconfiguration strategy is presented. In addition, the designs of both coarse- and fine-mode relative state estimators are presented. Formation flying simulations demonstrate the efficacy of the proposed control and coarse estimation. Furthermore, hardware tests are performed to test the computational efficiency of the control algorithms and to validate the fine-mode relative navigation filter.