Le projet de recherche financé par une subvention RDC du CRSNG et le CRIAQ est un partenariat entre Bombardier Aéronautique, Bell Helicopter, l'Université de Sherbrooke et l'Université Laval. Le principal objectif de ce projet est d'évaluer le potentiel de remplacer les actionneurs hydromécaniques par des actionneurs électromécaniques pour les commandes de vols primaires du Bell 407. La composante critique de l'actionneur électromécanique visé est un embrayage magnétorhéologique (MR). En effet, le fonctionnement de ce type d'embrayage est bien connu, mais la fiabilité ainsi que la durabilité de cette technologie restent à être prouvées. Le présent projet de maîtrise consiste donc à étudier la fiabilité ainsi que la durabilité d'un embrayage MR utilisé en glissement continu. Dans un premier temps, une analyse de fiabilité du système complet aux composantes (Top-Down) a été réalisée selon les méthodes et les techniques standards (FMEA et FTA) utilisées dans le domaine de l'aéronautique. Le manque d'informations concernant les modes de défaillance et la durabilité des embrayages MR a nécessité une étude expérimentale. Pour ce faire, un banc d'essais de longue durée complètement autonome a été conçu et fabriqué. Au total, 1750 heures de tests en glissement continu ont été réalisées sur des embrayages MR. Il y avait deux objectifs à ces tests. Le premier était d'étudier l'effet des paramètres d'opération (température, vitesse, couple) sur la durée de vie du fluide MR. Le deuxième était d'évaluer l'impact de la dégradation du fluide MR sur les performances d'un embrayage MR. Au final, le projet de recherche a permis de : 1. Évaluer les requis de fiabilité pour chacune des composantes d'un embrayage MR lorsqu'utilisé dans un système d'actuation pour des commandes de vol primaire d'un hélicoptère ; 2. Obtenir une compréhension plus fine du processus de dégradation du fluide MR et l'impact sur les performances des embrayages MR; 3. Doubler la durée de vie des embrayages MR par le développement d'une technique de circulation interne du fluide MR permettant l'utilisation d'un plus grand volume de fluide MR et ce, sans pénalité de poids, de volume et de coût.

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / With the increased concerns for reducing cost and improving reliability in today's telemetry systems, many users are employing simulation and automation to guarantee reliable telemetry systems operation. This places an increased demand on the remote capabilities of the equipment used in the telemetry system. Furthermore, emphasis has been placed on the ability to decrease the space and power consumption of the telemetry system to facilitate transportability of the a single telemetry system to multiple sites. Finally, today's telemetry systems demand that all equipment provide multiple functions to provide the maximum performance for the lowest system cost.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / To deliver high bandwidth, a ubiquitous inter-/intra-building cable plant consisting of single mode and multimode fiber as well as twisted pair copper is required. The selection of the "glue" to transport and interconnect distributed LANs with central facility resources over a pervasive cable plant is the focus of this paper. A description of the traditional problems that must be overcome to provide very high bandwidth beyond the narrow confines of a computer center is given. The applicability of Asynchronous Transfer Mode (ATM) switching (interconnection) and Synchronous Optical NETwork (SONET) (transport) for high bandwidth delivery is described using the environment and requirements of Sandia National Laboratories. Other methods for distributing high data rates are compared and contrasted. Sandia is implementing a standards based foundation utilizing a pervasive single mode fiber cable plant, SONET transport, and ATM switching to meet the goals of gigabit networking.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / As aircraft become more complex and require more resources over larger areas, the challenge of the test ranges is to provide economical solutions to move telemetry data from the test article to the data processing facility. Edwards AFB is in the process of upgrading the ground transmission facilities to transport data including telemetry using Asynchronous Transfer Mode (ATM). This paper documents the challenge of supporting telemetry over ATM, different approaches that are available, the benefits of using ATM, and discussion of candidate hardware options. The effort at Edwards include the linking of the major range facilities over a fiber optic backbone and links to other major test ranges in the Southwest Range Complex via microwave. The fiber optic backbone is expected to be OC-12c (622 Mbps) ATM supporting new capabilities as well as all of the legacy systems. The backbone system will be designed so that migration to OC-48 is possible without service disruption. The microwave links are multiple DS-3 capable. Some of these DS-3s may support legacy systems, but the ability to link ranges using ATM is expected simultaneously.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / As the flight test community moves into the 21st century, the ever increasing demand for higher telemetry data rates and the need to transport additional data types is becoming the challenge of every flight test range. The evolution of the flight test range has grown from low telemetry data rates and a few 2400 baud tracking sources into high-speed telemetry, GPS based tracking, networking, digital video, and more. Recognizing the need to change the way data is managed has resulted in an effort to redefine the work centers at the Air Force Flight Test Center (AFFTC) at Edwards AFB. The Technical Control Center (TCC) within the Ridley Mission Control Center at Edwards AFB is currently being relocated with the intent of achieving tomorrow’s vision, while supporting the missions of today. One major goal of this redefinition is the elimination of as much analog transmission equipment as possible in favor of digital transmission. The new digital range requires management of data and allocation of that management in different ways than the past. Moving to an all-digital range has advantages that are just now being realized. This paper outlines the current and future design, configuration, maintenance, and operation of the TCC and touches on how some of the other range functions are impacted. In addition, the challenges and benefits of implementing the next generation in range communications will be discussed.

Independent metering poses a possibility to improve energy efficiency of throttlecontrolled hydraulic single-rod cylinder drives. This paper deals with energetic potentials gained through variable circuitry that come along with independent metering. A method to assess energetic potentials is described, based on load specific, optimal operating modes. As a means of yielding maximum energy efficiency for a wide range of applications, a smooth mode switching algorithm that minimizes losses and allows good motion tracking is proposed. The mode switching algorithm is validated in simulation and on a test stand.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Asynchronous Transfer Mode (ATM) is a technology that is experiencing tremendous growth in the commercial telecommunications sector. Leveraging commercial investment and introducing ATM into today’s flight test range, while ensuring that all requirements are satisfied, are paying large dividends in capability and efficiency. The flight test community imposes unique requirements specifically with regards to telemetry that are not the norm of the commercial telecommunications industry. Efforts are underway at the Air Force Flight Test Center (AFFTC), Edwards Air Force Base (AFB) to implement an ATM system for all range communications. This paper addresses the unique requirements imposed by the flight test community, a revolutionary breakthrough from a commercial ATM vendor, and other challenges experienced while implementing this system. The system being implemented at Edwards will carry all types of range data over SONET/ATM hybrid equipment and interface to other flight test ranges and facilities over a mix of commercial leased lines and dedicated microwaves.

Thesis ((PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This dissertation proposes a multi-mode antenna element excited through a multiconductor feed. It is shown that each of the orthogonal transverse electromagnetic modes supported by the antenna feed results in a unique radiated far-field pattern that collectively allow for nearhemispherical field-of-view coverage. Three multi-mode antenna designs are presented: a dual-mode antenna, integrating a single linearly polarised dipole antenna with a co-located monopole, as well as two quad-mode antenna designs integrating two dual-polarised dipole elements with a co-located monopole element. The dual-mode antenna is excited through a balanced transmission line feed supporting both differential- and common-mode signals that, respectively, result in typical dipole-over-ground and monopole radiated far-field patterns. The quad-mode antennas are each fed through a quadraxial transmission line allowing for excitation through four orthogonal transverse electromagnetic port modes. To characterise the multi-mode response of the multi-mode antennas, generalised transformations are derived by which the multi-mode S-parameters and radiated far-fields can be calculated from the S-parameters and far-fields corresponding to single-ended excitations. These transformations are implemented to validate the response of a dual-mode and quad-mode antenna design through measurements. An equivalent network representation for active multi-mode antennas is presented, including generalised transformations relating the multi-mode signal and noise response of the low-noise amplifiers to the two-port S-parameters and noise parameters of the low-noise amplifiers. Through the use of classical beamforming algorithms, the performance of an active dual-mode and quadmode antenna is presented. In the case of the active dual-mode antenna, it is shown that through the added use of common-mode signals, a variation in sensitivity of less than 50% is achieved in the E-plane. Similarly, the additional excitation modes supported by the active quad-mode antenna is shown to result in a significant improvement in the polarimetric capabilities over the field-of-view coverage. / AFRIKAANSE OPSOMMING: Hierdie proefskrif stel ’n multimodale antenna element voor wat deur ’n multi-geleier transmissielyn gevoer word. Dit word gewys dat elk van die ortogonale transversale elektromagnetiese opwekkingsmodusse wat deur die antenna voer ondersteun word, ’n unieke vêrveld stralingspatroon skep, wat gesamentlik lei tot ’n hemisferiese gesigsveld. Drie multimodale antenna ontwerpe word voorgestel: ’n dubbelmodale antenna, waarin ’n enkel lineêrgepolariseerde dipool antenna en monopool mede-geleë word, asook twee viermodale antenna ontwerpe waarin twee dubbelgepolariseerde dipool elemente geïntegreer word met medegeleë monopool antenna elemente. Die dubbelmodale antenna word gevoer deur ’n gebalanseerde transmissielyn wat beide differensiële- en gemene-modus seine ondersteun, waar elk onderskeidelik dipool-oor-aardvlak en monopool stralingspatrone voortbring. Die viermodale antennas word elk gevoer deur vier-as transmissielyne wat vier ortogonale transversale elektromagnetiese opwekkingsmodusse ondersteun. Om die multimodale gedrag van die drie multimodale antennas te karakteriseer, word veralgemeende transformasies afgelei waardeur die multimodale strooiingsparameters asook die vêrveld stralingspatrone vanaf enkelpoort strooiingsparameters en vêrvelde bereken word. Hierdie transformasies word toegepas om die gedrag van ’n dubbel- en viermodale antenna ontwerp te karakteriseer deur metings. Ekwivalente netwerkvoorstellings vir aktiewe multimodale antennas word voorgestel, insluitend veralgemeende transformasies om die multimodale sein asook ruis gedrag van die lae-ruis versterkers betreklik te maak tot die tweepoort strooiingsparameters en ruisparameters van die laeruis versterkers. Deur gebruik te maak van klasieke bundelvormingsalgoritmes, word die gedrag van aktiewe dubbelmodale en viermodale antennas voorgestel. Vir die aktiewe dubbelmodale antenna word daar aangedui dat die gesamentlike gebruik van differensiële- en gemene-modus seine, ’n variasie in sensitiwiteit onder 50% tot gevolg het in die E-vlak. Soortgelyk word daar aangedui dat die addisionele opwekkingsmodusse wat deur die aktiewe viermodale antenna ondersteun word, tot ’n beduidende verbetering in die polarisasievermoë oor die gesigsveld lei.

<p>Problems associated with traffic, such as traffic congestionand pollution, have occurred in major urban areas in particulardue to the increased use of cars. One possible way to reducethe use of cars is to replace commuter trips by car with othermodes of transport, such as a combination of car and publictransport called Park&Ride. The aim of this thesis was tounderstand more about factors influencing the choice of modeand to find measures that could attract car drivers to Park&Ride. A stated preference survey has been conducted inorder to quantify some standard factors. The factors used inthis stated choice experiment were: security at the lot,availability of spaces at the parking lot, costs at the parkinglot and walking distances between the parking space and thestation. The results indicate that security at the Park&Ride facility is important. Both sexes assign a high value tosecure parking, but women are more willing to pay for lights atan unguarded parking lot. The results reveal that parkingfacilities, such as free parking and short distance betweenparking place and work at work, influence people’s choiceof mode. A general conclusion is that there is potential forincreasing the use of Park&Ride facilities, especiallyamong women and respondents over 30 years.</p><p><b>Key words:</b>Mode choice, valuation, traffic reduction,stated preference, factors, Park&Ride</p>

<p>”Att vara smal är något som väldigt många drömmer om. Mode och ideal lockar unga till bantning. Men det finns de som inget annat vill än att gå upp i vikt. Undervikt förknippas ofta med sjukdom eller ätstörningar men ibland beror det på det genetiska arvet eller en förhöjd ämnesomsättning. På grund av de förutfattade meningar som finns kring undervikt händer det ofta att smala personer blir mål för kommentarer eller avundsjuka. Möt dem som dagligen arbetar med undervikt samt tjejen som ensam kämpat med sin undervikt under flera år.”</p>