International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / This paper presents a new variable beamwidth antenna designed for use in telemetry tracking systems when a high gain/low gain antenna configuration is required. This antenna can be commanded to continuously vary its beamwidth between a high gain/narrow beamwidth mode of operation and a low gain/ wide beamwidth mode of operation. A design goal of a 4:1 increase in beamwidth has been set and a 3.0:1 increase has been achieved without causing any significant degradation in the shape of the antenna patterns and without generating exceedingly high sidelobes in the low gain setting. The beamwidth variation occurs continuously without any loss of data, boresight shift or jitter such as experienced with the operation of conventional implementations of the high gain/low gain antenna technique.

Regression models describingthe dependence between a univariate response and a set of covariates play a fundamental role in statistics. In the last two decades, a tremendous effort has been made in developing flexible regression techniques such as generalized additive models(GAMs) with the aim of modelling the expected value of a response variable as a sum of smooth unspecified functions of predictors. Many nonparametric regression methodologies exist includinglocal-weighted regressionand smoothing splines. Here the focus is on penalized regression spline methods which can be viewed as a generalization of smoothing splines with a more flexible choice of bases and penalties. This thesis addresses three issues. First, the problem of model misspecification is treated by extending the instrumental variable approach to the GAM context. Second, we study the theoretical and empirical properties of the confidence intervals for the smooth component functions of a GAM. Third, we consider the problem of variable selection within this flexible class of models. All results are supported by theoretical arguments and extensive simulation experiments which shed light on the practical performance of the methods discussed in this thesis.

Dans le domaine des sondages, il y a plusieurs méthodes d'estimer une moyenne ou un total d'une population. Une des techniques les plus pratiques est l'utilisation d'une variable auxiliaire ayant une corrélation avec la variable d'intérêt et dont les données sur toute la population sont connues. Dans ce mémoire, on va s'intéresser particulièrement à l'estimation d'une moyenne par le quotient. Dans ce cadre, on va traiter largement cette approche, en détaillant premièrement tout ce qui concerne l'estimateur par le quotient afin de répondre à toute question sur le sujet. Par la suite, on va étudier un cas particulier de l'estimation par le quotient lorsque la variable étudiée est dichotomique, en examinant les estimateurs possibles selon le mode de tirage, soit le tirage avec probabilités égales ou probabilités inégales avec ou sans remise. Dans le dernier chapitre, on présentera le cas où la variable auxiliaire est aussi dichotomique. Quatre estimateurs seront proposés pour estimer la moyenne de la population. On va analyser leurs propriétés dans le but de pouvoir les comparer. Afin que le traitement théorique soit valable, on va le concrétiser par des simulations avec des populations réelles et d'autres générées selon des paramètres donnés. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Estimateur, Quotient, Variable auxiliaire, Variable dichotomique.

The first topic of this thesis presents a novel VGA (variable gain amplifier) design which is applied in the AGC (automatic gain control) loop of digital video broadcasting - terrestrial (DVB-T) receivers. A total of three digital variable gain amplifiers (DVGA) are cascaded to provide a 70 dB dynamic range and 95 MHz operation frequency. The proposed digital VGA implemented by 0.35um 2P4M CMOS technology possesses 70 dB dynamic tuning range with a 0.3 dB gain error and 95 MHz bandwidth, and the power consumption is found to be 32.7 mW given a 3.3 V power supply. The second topic presents a design of a 60 ps peak-to-peak jitter, 80MHz, phase-locked loop (PLL) circuit for DVB-T receivers. The simulation results using the TSMC (Taiwan Semiconductor Manu-facturing Company) 0.35um 2P4M CMOS process show that the proposed PLL achieves as low as 60 ps peak-to-peak jitter when the output frequency is 80 MHz and the power consumption is merely 10.5 mW given a 3.3 V power supply.

This paper designs and implements a DSP-microprocessor based variable frequency motor drive. We control the induction motor with V/F scheme. This paper also analysis about Sine-PWM and Space-Vector-PWM. Compared with commonly used SPWM method, SVPWM has the advantages of higher voltage utilization, lower harmonic and lower switching loss. Also, it increases the efficiency of an inverter. To calculate duty cycle this paper support different update model, so symmetrical and asymmetrical PWM are generated. To analyse about spectra, and we can find the asymmetrical PWM restrain the harmonic.

Abstract: This paper designs and implements a DSP-microprocessor based motor driver. We control the induction motor with V/F scheme. And we module all circuits with PCB Layout.This Inverter is compose of digital board and analog-power board. We connect two parts, and we use a three phase induction motorto to be the load. Because the digital board is compose of DSP, it is to fit a lot of mathematics. It is easy to use the software to present the theory. So the paper compute the three phase gate signals with asymmetrical Pulse-Width-Modulation model.

Humans have a complex musculoskeletal arrangement which gives them great behavioural flexibility. As well as simply moving their legs, they can modulate the impedance of them. Variable impedance has become a large field in robotics, and tailoring the impedance of a robot to a particular task can improve efficiency, stability, and potentially safety. Locomotion of a bipedal robot is a perfect example of a task for which variable impedance may provide such advantages, since it is a dynamic movement which involves periodic ground impacts. This thesis explores the creation of two novel bipedal robots with variable impedance joints. These robots aim to achieve some of the benefits of compliance, while retaining the behavioural flexibility to be truly versatile machines. The field of variable impedance actuators is explored and evaluated, before the design of the robots is presented. Of the two robots, BLUE (Bipedal Locomotion at the University of Edinburgh) has a 700mm hip rotation height, and is a saggital plane biped. miniBLUE has a hip rotation height of 465mm, and includes additional joints to allow hip adduction and abduction. Rapid prototyping techniques were utilised in the creation of both robots, and both robots are based around a custom, high performance electronics and communication architecture. The human walking cycle is analysed and a simple, parameterised representation developed. Walking trajectories gathered from human motion capture data, and generated from high level gait determinants are evaluated in dynamic simulation, and then on BLUE. With the robot being capable of locomotion, we explore the effect of varying stiffness on efficiency, and find that changing the stiffness can have an effect on the energy efficiency of the movement. Finally, we introduce a system for goal-based teleoperation of the robots, in which parameters are extracted from a user in a motion capture suit and replicated by the robot. In this way, the robot produces the same overall locomotion as the human, but with joint trajectories and stiffnesses that are more suited for its dynamics.

abstract: Admittance control with fixed damping has been a successful control strategy in previous human-robotic interaction research. This research implements a variable damping admittance controller in a 7-DOF robotic arm coupled with a human subject’s arm at the end effector to study the trade-off of agility and stability and aims to produce a control scheme which displays both fast rise time and stability. The variable damping controller uses a measure of intent of movement to vary damping to aid the user’s movement to a target. The range of damping values is bounded by incorporating knowledge of a human arm to ensure the stability of the coupled human-robot system. Human subjects completed experiments with fixed positive, fixed negative, and variable damping controllers to evaluate the variable damping controller’s ability to increase agility and stability. Comparisons of the two fixed damping controllers showed as fixed damping increased, the coupled human-robot system reacted with less overshoot at the expense of rise time, which is used as a measure of agility. The inverse was also true; as damping became increasingly negative, the overshoot and stability of the system was compromised, while the rise time became faster. Analysis of the variable damping controller demonstrated humans could extract the benefits of the variable damping controller in its ability to increase agility in comparison to a positive damping controller and increase stability in comparison to a negative damping controller. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2019

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / Remote sensing satellites are typically low earth orbit, and often transmit the data gathered with the remote sensors to ground stations at locations on earth. These transmissions are band limited, and must operate within a 375 MHz bandwidth in the X-Band spectrum. This can present a limitation to the amount of data that can be transmitted during the short duration of a pass (typically less than 15 minutes). It is then highly desirable to increase the bandwidth efficiency of a system for data transmission in a remote sensing downlink. This paper describes a method of achieving higher efficiency by pre-programming the satellite to adjust the modulation and coding based in at least part on the slant range to the receiving ground station. The system uses variable coding and modulation to adjust to the slant range to the ground station to achieve a throughput increase of more than 50% of the data transferred during a pass using the currently accepted technology.

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