The aim of this thesis is to investigate the development and control of electro-pneumatic actuators in a haptic teleoperation system. For controlling the mass flow rate of such actuators, two types of valve technology are sudied, i.e. solenoid (on/off) valve and proportional servovalve. The servovalves have found widespread applications in which high accuracy of force/position control are needed. They are however typically expensive due to the requirements of high-precision manufacturing. Therefore, the low-cost solenoid valves can be an alternative to the servovalves for achieving acceptable-performance pneumatic control. Generally, the highly nonlinear of the pneumatic actuator is heightened when it uses on/off solenoid valves instead of servovalves. In this case, precise control is challenging due to the discrete-input nature of the system. Our first objective is to demonstrate that it is possible to design an acceptable performance teleoperation system using master-slave robots that have pneumatic actuators equipped with only inexpensive on/off solenoid valves. To control efficiently the switching valves, several control approaches have been proposed, namely pulse width modulation (PWM), hybrid algorithm, and sliding mode control. A hybrid control theory, which includes more switching control modes, than PWM, allows to reduce the chattering problem and improve the energy consumption of the valves. Another strategy (i.e. a sliding mode control), which does not depend on the pneumatic model, is proposed. This control stratgy allows to perform not only the transparent analysis but also the stability analysis. In order to improve the dynamic performance and reduce the chattering problem in solenoid valve actuated pneumatic teleoperation systems, a five-mode sliding control scheme has been used, which can be considered as an extension of the three-mode sliding controller. Our study demonstrates that by increasing the number of possible control actions for the valves, we can reduce the valves' switching activities, hence improving the valve's life times at no cost to teleoperation transparency. The second objective of the thesis involves in implementing the proportional servovalves on the pneumatic teleoperation system. A comparison related to the teleoperation performance between an on/off valve and a servovalve is carried out. In experiments, it is observed that with the bilateral teleoperation architecture employing solenoid valves or servovalves, satisfactory force and position tracking between the master and the slave is obtained. In bilateral teleoperation control, force sensors are often omitted to save cost and to lessen weight and volume. Therefore, another aspect of our work consists in using observers for an estimation of operator and environment forces. Experimental results show that acceptable teleoperation transparency based on a simple Nicosia observer and a tangent linear control approach can be achieved.

We investigate, in this thesis, the use of Hierarchical Modulation (HM), a physical layer technique that enables to exploit multiuser diversity, for resource allocation in OFDMA-based systems with and without use of relaying, so as to improve the system capacity. HM allows the sharing of the resources, namely subcarriers and power, between users of different radio conditions by sending an additional stream to a user with good radio conditions on a subcarrier that was initially allocated to carry an original stream to a user with lower radio conditions. And this, without affecting the original user's rate nor the total amount of power assigned to the shared subcarrier. In the literature, most of the works that consider the use of HM focus solely on the physical layer performance, notably in terms of the bit error rate. And this for a static user scenario,i.e., with a fixed number of users in the system, each with an infinite service duration. This configuration however does not reflect the real system behavior where the number of users is dynamic, i.e., the users come to the system at random time epochs and leave it after a finite duration, corresponding to the completion of their services. The study of the system at the flow-level, as opposed to the packet level, for a dynamic user configuration, enables us to investigate the realistic relationship between capacity and demand and to quantify several system-level performance metrics, such as mean transfer times and blocking rates, which are meaningful both to the user and the network operator/provider.

This thesis presents an independent analysis of the data from 3-He-filled proportional counters from the third phase of the Sudbury Neutrino Observatory (SNO) data. These counters were deployed in SNO's heavy water to independently detect neutrons produced by the neutral current interaction of 8-B solar neutrinos with deuterium. Previously published results from this phase were based on a spectral analysis of the energy deposited in the proportional counters. The work in this thesis introduces a new observable based on the time-profile of the ionization in the counters. The inclusion of this observable in a maximum-likelihood fit increases the potential to distinguish neutrons from backgrounds which are primarily due to alpha-decays. The combination of this new observable with the energy deposited in the counters results in a more accurate determination of the number of neutrons. The analysis presented in this thesis was limited to one third of the data from the proportional counters, uniformly distributed in time. This limitation was imposed to reconcile different time-lines between the submission of this thesis, a thorough review of this work by the SNO Collaboration and results from an independent analysis that is still underway. Analysis of this reduced data set determined that 398 +/- 29 (stat.) +/- 9 (sys.) neutrons were detected in this reduced data-set. The number compares well to the previous analysis of the data, based only on a spectral analysis of the deposited energy, which determined that 410 +/- 44 (stat.) +/- 9 (sys.) were detected in the same time period. The analysis presented here has led to a substantial increase in the statistical accuracy. Assuming that the statistical accuracy will increase when the full data set is analyzed, the results from this thesis would bring the uncertainty in the 8-B solar neutrino flux to down 6.8% from 8.5% in the previously published results. The work from the thesis is intended to be included in a future analysis of the SNO data and will result in a more accurate measurement of the total flux of solar neutrinos from 8-B as well as reduce the uncertainty in the $\theta_{12}$ neutrino oscillation mixing angle. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2009-09-16 15:56:28.195

The analysis of survival data with a possible cure fraction has attracted much interest in the last two decades. Various models and estimating methods have been proposed for such data and they have been applied in many fields, especially in cancer clinical trials. In the thesis, we consider some new general cure models, which include existing survival models as their special cases. We also consider a nonparametric estimation of cure rate. The estimator is proved consistent and asymptotically normal. We also consider the application of proportional density for cure data and the analysis of length-biased cure data. / Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2012-01-26 09:53:08.127

The information on the volume of traffic flowing between all possible origin and destination pairs in an IP network during a given period of time is generally referred to as traffic matrix (TM). This information, which is very important for various traffic engineering tasks, is very costly and difficult to obtain on large operational IP network, consequently it is often inferred from readily available link load measurements. In this thesis, we evaluated 5 TM estimation techniques, namely Tomogravity (TG), Entropy Maximization (EM), Quadratic Programming (QP), Linear Programming (LP) and Neural Network (NN) with gravity and worst-case bound (WCB) initial estimates. We found that the EM technique performed best, consistently, in most of our simulations and that the gravity model yielded better initial estimates than the WCB model. A hybrid of these techniques did not result in considerable decrease in estimation errors. We, however, achieved most significant reduction in errors by combining iterative proportionally-fitted estimates with the EM technique. Therefore, we propose this technique as a viable approach for estimating the traffic matrix of large-scale IP networks.

Emanating from classical Weibull mixture models we propose a framework for clustering survival data with various proportionality restrictions imposed. By introducing mixtures of Weibull proportional hazards models on a multivariate data set a parametric cluster approach based on the EM-algorithm is carried out. The problem of non-response in the data is considered. The application example is a real life data set stemming from the analysis of a world-wide operating eCommerce application. Sessions are clustered due to the dwell times a user spends on certain page-areas. The solution allows for the interpretation of the navigation behavior in terms of survival and hazard functions. A software implementation by means of an R package is provided. (author´s abstract) / Series: Research Report Series / Department of Statistics and Mathematics

Due to the prevalence of pulse encoders for system state information, an all-digital proportional-integral-derivative (ADPID) is proposed as an alternative to traditional analog and digital PID controllers. The basic concept of an ADPID stems from the use of pulse-width-modulation (PWM) control signals for continuous-time dynamical systems, in that the controllers proportional, integral and derivative actions are converted into pulses by means of standard up-down digital counters and other digital logic devices. An ADPID eliminates the need for analog-digital and digital-analog conversion, which can be costly and may introduce error and delay into the system. In the proposed ADPID, the unaltered output from a pulse encoder attached to the systems output can be interpreted directly. After defining a pulse train to represent the desired output of the encoder, an error signal is formed then processed by the ADPID. The resulting ADPID output or control signal is in PWM format, and can be fed directly into the target system without digital-to-analog conversion. In addition to proposing an architecture for the ADPID, rules are presented to enable control engineers to design ADPIDs for a variety of applications.

This Master of Applied Science thesis presents an inverter control system design and implementation with active damping of LCL filter resonance for a single phase grid-connected Distributed Power Generation (DPGS). The focus of the thesis is to actively damp the LCL filter resonance while keeping inverter control variables well regulated. The mathematical model of the LCL filter is analyzed and the filter is designed. Then, a PLL, and a PI compensator in the synchronous reference frame, and a PR compensator in stationary reference frame along a notch filter in cascade are designed and implemented. System level simulation and implementation are conducted. The idea of systematic applying the low loss power conversion topology, effective grid condition detection, grid synchronization, and advanced signal processing theory provides some advantages for single phase grid-connected inverter control design to meet the standard specifications of the interaction between the DPGS and utility grid. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2014-06-26 17:06:03.693

The information on the volume of traffic flowing between all possible origin and destination pairs in an IP network during a given period of time is generally referred to as traffic matrix (TM). This information, which is very important for various traffic engineering tasks, is very costly and difficult to obtain on large operational IP network, consequently it is often inferred from readily available link load measurements. In this thesis, we evaluated 5 TM estimation techniques, namely Tomogravity (TG), Entropy Maximization (EM), Quadratic Programming (QP), Linear Programming (LP) and Neural Network (NN) with gravity and worst-case bound (WCB) initial estimates. We found that the EM technique performed best, consistently, in most of our simulations and that the gravity model yielded better initial estimates than the WCB model. A hybrid of these techniques did not result in considerable decrease in estimation errors. We, however, achieved most significant reduction in errors by combining iterative proportionally-fitted estimates with the EM technique. Therefore, we propose this technique as a viable approach for estimating the traffic matrix of large-scale IP networks.

A study of pre-service primary school teachers in Singapore and the United States revealed superior performance by the Singaporeans on proportional reasoning problems. Analysis of solutions showed the Singapore future teachers were more likely to use unitary and benchmark approaches than were their American counterparts. Conclusions include suggestions for programs intended to improve the performance of prospective elementary school teachers on proportional reasoning problems.