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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
621

Multi-sensor Data Fusion for Traffic Speed and Travel Time Estimation

Bachmann, Christian 01 December 2011 (has links)
In this thesis, seven multi-sensor data fusion based estimation techniques are investigated. All methods are compared in terms of their ability to fuse data from loop detectors and Bluetooth tracked probe vehicles to accurately estimate freeway traffic speed. In the first case study, data generated from a microsimulation model are used to assess how data fusion might perform with present day conditions, having few probe vehicles, and what sort of improvement might result from an increased proportion of vehicles carrying Bluetooth-enabled devices in the future. In the second case study, data collected from the real-world Bluetooth traffic monitoring system are fused with corresponding loop detector data and the results are compared against GPS collected probe vehicle data, demonstrating the feasibility of implementing data fusion for real-time traffic monitoring today. This research constitutes the most comprehensive evaluation of data fusion techniques for traffic speed estimation known to the author.
622

EVALUATION OF SOLID STATE ACCELEROMETER SENSOR FOR EFFECTIVE POSITION ESTIMATION

Lele, Meenal Anand 22 November 2010 (has links)
Inertial sensors such as Gyroscope and Accelerometer show systematic as well as random errors in the measurement. Furthermore, double integration method shows accumulation of error in position estimation due to inherent accelerometer bias drift. The primary objective of this research was to evaluate ADXL 335 acceleration sensor for better position estimation using acceleration bias drift error model. In addition, measurement data was recorded with four point rotation test for investigation of error characteristics. The fitted model was validated by using nonlinear regression analysis. The secondary objective was to examine the effect of bias drift and scale factor errors by introducing error model in Kalman Filter smoothing algorithm. The study showed that the accelerometer may be used for short distance mobile robot position estimation. This research would also help to establish a generalized test procedure for evaluation of accelerometer in terms of sensitivity, accuracy and data reliability.
623

An Improved Path Integration Mechanism Using Neural Fields Which Implement A Biologically Plausible Analogue To A Kalman Filter

Connors, Warren Anthoney 22 February 2013 (has links)
Interaction with the world is necessary for both animals and robots to complete tasks. This interaction requires a sense of self, or the orientation of the robot or animal with respect to the world. Creating and maintaining this model is a task which is easily maintained by animals, however can be difficult for robots due to the uncertainties in the world, sensing, and movement of the robot. This estimation difficulty is increased in sensory deprived environments, where no external, inputs are available to correct the estimate. Therefore, self generated cues of movement are needed, such as vestibular input in an animal, or accelerometer input in a robot. In spite of the difficulties, animals can easily maintain this model. This leads to the question of whether we can learn from nature by examining the biological mechanisms for pose estimation in animals. Previous work has shown that neural fields coupled with a mechanism for updating the estimate can be used to maintain a pose estimate through a sustained area of activity called a packet. Analysis of this mechanism however has shown conditions where the field can provide unexpected results or break down due to high accelerations input into the field. This analysis illustrates the challenges of controlling the activity packet size under strong inputs, and a limited speed capability using the existing mechanism. As a result of this, a novel weight combination method is proposed to provide a higher speed and increased robustness. The results of this is an increase of over two times the existing speed capability, and a resistance of the field to break down under strong rotational inputs. This updated neural field model provides a method for maintaining a stable pose estimate. To show this, a novel comparison between the proposed neural field model and the Kalman filter is considered, resulting in comparable performance in pose prediction. This work shows that an updated neural field model provides a biologically plausible pose prediction model using Bayesian inference, providing a biological analogue to a Kalman filter.
624

Robust variance estimation for ranking and selection

Marshall, Williams S., IV 12 1900 (has links)
No description available.
625

On-Line Optimization for a Batch-Fed Copolymerization Reactor with Partial State Measurement

OKORAFO, ONYINYE 06 October 2009 (has links)
Polymerization processes require adequate monitoring to ensure that the final product meets specification. Various on-line measuring techniques have been developed and implemented to track polymer properties in reactors. For most processes, however, on-line measurement cannot be implemented. In other situations, certain polymer properties or states might not be measurable and hence have to be estimated. This work deals with improving an on-line optimization technique and demonstrating its eff ectiveness by sensitivity analysis. In addition, state estimation is used as a tool to reconstruct states that are unavailable for measurement in a styrene and butyl methacrylate batch-fed solution free-radical copolymerization process subject to on-line optimization. A hybrid extended Kalman filter is used to observe the nonlinear dynamic system which is subject to real-time dynamic optimization. With very limited measurement information, the states of the system were reconstructed. Additional unobservable quantities were reconstructed using the process model and estimated states. / Thesis (Master, Chemical Engineering) -- Queen's University, 2009-09-28 16:02:55.974
626

Channel estimation and training sequence design in one-way and two-way relay networks

Wang, Gongpu Unknown Date
No description available.
627

Nonlinear Robust Observers for Simultaneous State and Fault Estimation

Raoufi, Reza Unknown Date
No description available.
628

Estimability and testability in linear models

Alalouf, Serge. January 1975 (has links)
No description available.
629

The array-matrix concept- a new approach to multivariate analysis.

Tait, George Rodney. January 1971 (has links)
No description available.
630

Some statistical properties of Laguerre coefficient estimates.

Kaufman, David. January 1970 (has links)
No description available.

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