Gaussian Mixture Reduction for Bayesian Target Tracking in Clutter

The Bayesian solution for tracking a target in clutter results naturally in a target state Gaussian mixture probability density function (pdf) which is a sum of weighted Gaussian pdf\u27s, or mixture components. As new tracking measurements are received, the number of mixture components increases without bound, and eventually a reduced-component approximation of the original Gaussian mixture pdf is necessary to evaluate the target state pdf efficiently while maintaining good tracking performance. Many approximation methods exist, but these methods are either ad hoc or use rather crude approximation techniques. Recent studies have shown that a measure-function-based mixture reduction algorithm (MRA) may be used to generate a high-quality reduced-component approximation to the original target state Gaussian mixture pdf. To date, the Integral Square Error (ISE) cost-function-based MRA has been shown to provide better tracking performance than any previously published Bayesian tracking in heavy clutter algorithm. Research conducted for this thesis has led to the development of a new measure function, the Correlation Measure (CM), which gauges the similarity between a full- and reduced-component Gaussian mixture pdf. This new measure function is implemented in an MRA and tested in a simulated scenario of a single target in heavy clutter. Results indicate that the CM MRA provides slightly better performance than the ISE cost-function-based MRA, but only by a small margin

Gaussian Mixture Reduction of Tracking Multiple Maneuvering Targets in Clutter

The problem of tracking multiple maneuvering targets in clutter naturally leads to a Gaussian mixture representation of the Provability Density Function (PDF) of the target state vector. State-of-the-art Multiple Hypothesis Tracking (MHT) techniques maintain the mean, covariance and probability weight corresponding to each hypothesis, yet they rely on ad hoc merging and pruning rules to control the growth of hypotheses

Segmenting and tracking objects in video sequences based on graphical probabilistic models

Ph.DDOCTOR OF PHILOSOPH

Navigation/traffic control satellite mission study. Volume 1 - Summary

System of satellites, ground stations, and hardware of various user craft for transoceanic traffic contro

Analysis of potential muscular determinants of the preferred walk-run transition speed in human gait

textThe spontaneous transition from walking to running as walking speed increases is an intriguing neuromotor phenomenon that consistently occurs near 2 m/s in humans. Despite investigations of various metabolic and biomechanical factors, the determinants of the transition have remained elusive. However, no study has investigated the potential influence of intrinsic muscle properties and fiber-tendon interactions as potential determinants. The overall objective of this research was to use a forward dynamical simulation framework in three studies to identify the potential influence of these muscular determinants on the preferred walk-run transition speed (PTS). In the first study, individual muscle force production was examined as walking speed increased to assess the influence of intrinsic muscle properties on the PTS. The simulation data showed that of all the major lower-extremity muscle groups examined, the ankle plantar flexors were the only muscles to show a decrease in force production, despite an increase in activation, as walking speed approached the PTS. The force reduction was attributed to adverse contractile conditions. Considering the importance of the plantar flexors to providing body support and forward progression, the impaired force generation was deemed an important determinant of the PTS. In the second study, individual muscle contributions to body support and forward progression in walking and running at the PTS were quantified to clarify differences in muscle function between the two gait modes. The most distinctive difference was the reduced soleus contribution to forward progression in running. All other muscle groups performed similarly between the two gait modes. In the third study, individual muscle fiber and tendon mechanical work was quantified to examine whether there existed an energetic advantage during walking and running above and below the PTS. The total muscle fiber work was found to be higher in running than walking below the PTS, and higher in walking than running above the PTS. In addition, tendon elasticity utilization was lower in running below the PTS than in running above the PTS. These results highlight the advantages of each gait mode and suggest why walking below the PTS and running above the PTS are the preferred gaits.Mechanical Engineerin

An assessment on the unsteady flow distortion generated by an S-duct intake

Closer integration between the fuselage and the propulsion system is expected for futureaircraft toreducefuel consumption, emissions, weight and drag. The use of embedded or partially embedded propulsion systems may require the use of complex intakes. However, thiscanresult in unsteady flow distortion which can adversely affect the propulsion system efficiency and stability. This works assesses the characteristics of the unsteady flow with a view to the potential flow distortion presented to the compression system.Particle image velocimetry is used to measure the flow distortion generated by an S-shaped intake.The time-resolved tracking of the idealized relative incidence angle revealed that most frequent distortion events exhibited90°exposure sector and upto±5°meanrelativeincidence. The imposition of a thicker boundary at the S-duct inlet increased the probability of distortion events that are characterized by a longer exposure sector and higher relative incidence angles.Because of these characteristics, thedistortion caused by the S-duct intake could induce instabilities that are detrimental for the propulsion system performances and stability. Overall, this work proposes a new method to assess thepossible relativeincidence angle on the compressor rotor taking into account the intake flow unsteadiness

Robust Multi-Object Tracking: A Labeled Random Finite Set Approach

The labeled random finite set based generalized multi-Bernoulli filter is a tractable analytic solution for the multi-object tracking problem. The robustness of this filter is dependent on certain knowledge regarding the multi-object system being available to the filter. This dissertation presents techniques for robust tracking, constructed upon the labeled random finite set framework, where complete information regarding the system is unavailable