This study explores the association between media exposure and women’s body perceptions in Egypt. The thin ideal perpetuated through the media, eating disorders and body dissatisfaction and drive for thinness were thought to be a culturally linked phenomena confined to Western societies. This study has contributed to the debate on cultural determinism of eating disorders and body dissatisfaction in women as it has shown that these concepts are on the rise in non-Western societies in general and Egypt in specific. When exposed to media messages, women in Egypt demonstrated eating disordered attitudes, body dissatisfaction feelings and also chose other compensatory behaviors such as veiling, fasting, and following diet.

This thesis presents different state estimation techniques for speed sensorlees field oriented control of induction motors. The theoretical basis of each algorithm is explained in detail and its performance is tested with simulations and experiments individually. First, a stochastical nonlinear state estimator, Extended Kalman Filter (EKF) is presented. The motor model designed for EKF application involves rotor speed, dq-axis rotor fluxes and dq-axis stator currents. Thus, using this observer the rotor speed and rotor fluxes are estimated simultaneously. Different from the widely accepted use of EKF, in which it is optimized for either steady-state or transient operations, here using adjustable noise level process algorithm the optimization of EKF has been done for both states / the steady-state and the transient-state of operations. Additionally, the measurement noise immunity of EKF is also investigated. Second, Unscented Kalman Filter (UKF), which is an updated version of EKF, is proposed as a state estimator for speed sensorless field oriented control of induction motors. UKF state update computations, different from EKF, are derivative free and they do not involve costly calculation of Jacobian matrices. Moreover, variance of each state is not assumed Gaussian, therefore a more realistic approach is provided by UKF. In this work, the superiority of UKF is shown in the state estimation of induction motor. Third, Model Reference Adaptive System is studied as a state estimator. Two different methods, back emf scheme and reactive power scheme, are applied to MRAS algorithm to estimate rotor speed. Finally, a flux estimator and an open-loop speed estimator combination is employed to observe stator-rotor fluxes, rotor-flux angle and rotor speed. In flux estimator, voltage model is assisted by current model via a closed-loop to compensate voltage model&rsquo / s disadvantages.

Els robots caminadors presenten alguns avantatges respecte als tradicionals robots mòbils amb rodes, que es resumeixen en major mobilitat i capacitat de superació d'obstacles. Un dels principals problemes actuals en el desenvolupament de robots caminadors és l'elevat consum energètic i la poca autonomia, com a conseqüència de l'elevada massa dels accionaments i del seu rendiment limitat.Un primer objectiu d'aquesta tesi és desenvolupar i caracteritzar energèticament un accionament rotatiu per a les articulacions de la pota d'un robot caminador. Un cop desenvolupat aquest accionament s'analitza el comportament energètic global de la pota.La pota dissenyada és de tipus insecte i l'aplicació considerada és un robot hexàpode. L'accionament rotatiu consta de tres elements: un motor de corrent continu, una transmissió per corretja dentada i un reductor Harmonic Drive. El conjunt d'aquest reductor s'ha dissenyat específicament per a aquesta aplicació, i materialitza també l'enllaç de cada articulació de la pota.Per tal de determinar els requeriments mecànics a les articulacions, s'ha portat a terme una simulació dinàmica del moviment de la pota. Aquesta simulació s'ha realitzat considerant que les articulacions del mecanisme són ideals. Les resistències passives d'aquestes es tracten posteriorment al analitzar el comportament del reductor. Els resultats obtinguts són els parells requerits a les diferents articulacions al llarg d'un cicle.Amb l'objectiu de determinar el comportament real dels components de l'accionament, per a diferents condicions de funcionament, s'han plantejat i realitzat diverses sèries d'experiments. Per portar a terme els experiments ha estat necessària la construcció d'un prototipus de l'accionament. A partir de les dades experimentals s'han definit uns models matemàtics que representen les resistències passives a cada component de l'accionament per a diferents condicions de funcionament. S'ha realitzat un ajust per mínims quadràtics per tal determinar els paràmetres dels models que millor ajusten els resultats a les dades experimentals.Com que cada motor treballa com tal o com fre, segons la fase del moviment, s'ha analitzat en detall el funcionament d'una màquina elèctrica de corrent continu d'imants permanents, des del punt de vista de la conversió de potència elèctrica en mecànica i viceversa, en els 4 quadrants i tenint en compte els diferents modes de funcionament: com a motor, com a fre-generador i com a fre.Posteriorment s'han definit uns models globals del comportament mecànic dels elements de transmissió de l'accionament: la corretja dentada i el reductor HD, que integren la modelització de les resistències passives i també inclouen la inèrcia de les parts mòbils de cada element.Finalment s'ha realitzat la simulació dels tres accionaments d'una pota al llarg d'un cicle de l'anadura del robot, a partir dels requeriments de parell i velocitat angular a cada articulació i utilitzant els models dels elements definits anteriorment. L'objectiu és estimar l'energia intercanviada a cada element de l'accionament, avaluant per separat l'energia transmesa en sentit directe, des de l'alimentació del motor a la sortida del reductor, i en sentit invers. El resultat més important és l'estimació de l'energia elèctrica que cal subministrar a cada motor per cada cicle de moviment de la pota.Dels diversos casos analitzats se'n treu la conclusió que l'energia elèctrica que cal subministrar als motors és sempre molt superior, de l'ordre de 30 vegades, a l'energia mecànica que l'accionament transmet a l'articulació. La despesa energètica dels motors depèn poc de les condicions de càrrega a les que està sotmesa la pota, en canvi el moviment que descriuen les articulacions al llarg del cicle hi té una influència important. Reduint el recorregut angular del moviment de les articulacions s'aconsegueix un considerable estalvi energètic, doncs disminueix l'energia dissipada per les resistències passives. / Walking robots have some advantages respect to the traditional mobile wheeled robots. These can be summarised in superior mobility and the capacity to overcome obstacles. One of the main problems in the development of walking robots is the high energy consumption and the low autonomy of operation, due to the high mass of the actuators and their limited efficiency.A first objective of this thesis is to develop a rotary actuator, for the leg pin joints of a walking robot, and to characterize it energetically. Once the actuator is developed, leg global energetic performance is analysed.The leg design is according to an insect type leg and the considered application is a hexapod robot. The rotary actuator consists of three elements: a DC electric motor, a synchronous belt transmission and a Harmonic Drive gear reducer. Gear assembly has been particularly designed for this application, and integrates pin joint implementation.In order to determine the mechanical specifications at the joints, a dynamic simulation of the leg movement has been carried out. For this simulation pin joints in the mechanism have been considered as ideal joints. Resistance to motion at the joints are taken into account later, when gear operation is analysed. Results from the simulation are the required torques at the different joints along a walking cycle.Several series of experiments have been planned and carried out in order to work out the real behaviour of the actuator components under different working conditions. The construction of an actuator prototype has been necessary for the experimentation.Then derived from the experimental data, mathematical models that estimate resistance to motion at every actuator component as a function of the working conditions, have been defined. Parameters in the models to best fit the experimental data have been identified by least square approximations.Every DC motor works as a motor or as a brake depending on the movement stage. Therefore the operation of a permanent magnet DC electric machine has been analysed, from the point of view of the conversion of electrical power into mechanical and vice versa. This was performed taking into account the different operation modes: as a motor, as a brake-generator and as a brake.Global models that represent the mechanical behaviour of the transmission components in the actuator have been defined: the synchronous belt and the HD gear. These models integrate resistance to motion estimation and also the inertia of the mobile parts of every element. Finally, starting from the torque and angular velocity requirements at every joint and using the models of the elements described above, the simulation of the three actuators of a leg along a gait cycle of the robot has been carried out. The objective was to estimate the exchanged energy at every element of the actuator, separately calculating the transmitted energy in both directions: from the motor power supply to the output of the gear reducer and in reverse. The main result was the estimation of the electrical energy that must be supplied to every motor per leg movement cycle. From the several cases that have been analysed, it can be concluded that the electrical energy that has to be supplied to the motors is always much higher, around 30 times higher, than the mechanical energy that the actuator transmits to the joint. Motor energetic consumption has low dependence on leg load condition, but pin joint movement along a cycle has a great influence on it. Reducing the angular run of pin joint movements is a way to obtain substantial energy savings, since it decreases the resistance to motion energy dissipation.

Safety, performance and driving comforts are given high importance while developing modern day cars. All-Wheel Drive vehicles are exactly designed to fulfill such requirements. In modern times, human concern towards depleting fossil fuels and cognizance of ecological issues have led to new innovations in the field of Automotive engineering. One such outcome of the above process is the birth of electrical hybrid vehicles. The product under investigation is a combination of all wheel drive and hybrid system. A superior fuel economy can be achieved using hybrid system and optimized vehicle dynamic forces are accomplished by torque vectoring action which in turn provides All-Wheel Drive capabilities. Heat generation is inevitable whenever there is a conversion of energy from one form into another. In this master thesis investigation, a thermal simulation model for the product is built using 1D simulation tool AMESim and validation is done against the vehicle driving test data. AMESim tool was chosen for its proven track record related to vehicle thermal management. The vehicle CAN data are handled in MATLAB. In a nutshell, Simulation model accounts for heat generation sources, oil flow paths, power loss modeling and heat transfer phenomena. The final simulation model should be able to predict the transient temperature evolution in the rear drive when the speed and torque of motor is supplied as input. This simulation model can efficiently predict temperature patterns at various locations such as casing, motor inner parts as well as coolant at different places. Various driving cases were tried as input including harsh (high torque, low speed) ones. Simulation models like this helps Engineers in trying out new cooling strategies. Flow path optimization, flow rate, convection area, coolant pump controlling etc are the few variables worth mentioning in this regard.

Det övergripande syftet med den här uppsatsen var att undersöka vad som påverkar unga mopedförares intentioner till att köra alkoholpåverkade.  Ytterligare ett syfte var att belysa de generella attityder till alkohol- och trafikrelaterade frågor som finns bland svenska ungdomar. Samtliga resultat och analyser baserades på en enkätundersökning utförd av Statens väg- och transportforskningsinstitut (VTI). Enkäten vände sig till gymnasieelever och i analyserna behandlades svar från 1 933 elever i åldersintervallet 15 – 21 år. De statistiska analyserna innefattade χ2-test samt en ordinal logistisk regressionsmodell. Resultaten visade att ungdomarna generellt såg det som oacceptabelt att köra moped med alkohol i blodet. Dock trodde de inte i riktigt lika hög utsträckning att bästa kompisen såg det som oacceptabelt. Det som visade sig ha störst påverkan på ungdomarnas intentioner till att köra mopedonyktra var hur troligt de ansåg det vara att bästa kompisen skulle köra i samma situation. Resultaten visade även att personer som tidigare kört påverkade besitter en klart högre intention att åter köra mopedonyktra. / The overall objective of this report was to examine what affect young moped driver’s intentions to drive after drinking alcohol. A further aim was to illustrate Swedish adolescent’s attitudes towards alcohol and traffic in general. All results and analysis are based on a survey created by Swedish National Road and Transport Research Institute (VTI). The survey was addressed to high school students and the analysis consisted of answers from 1 933 students in the age of 15 - 21 years. The statistical analysis included χ2-tests as well as an ordinal logistic regression model. The results showed that adolescents in general thought it was an unacceptable behavior to drink and drive. However, the extent of expected acceptance level was higher when assessing their friend’s opinion. What proved to be most essential for the adolescent’s intentions was how likely they considered it to be that their best friends would drive in the same situation. The results also showed that a person with earlier experience of driving a moped with influence of alcohol or drugs has a clearly higher intention to drink and drive again.

The trend toward ever-expanding variable speed induction motor applications results in the need for reliable condition monitoring and detection schemes for closed-loop motor-drive systems. This research focuses on the detection of air gap eccentricity in induction motors supplied by a vector-controlled drive. The majority of existing eccentricity detection techniques is based on monitoring fault harmonics in the stator current. This research analyzes the distribution of the eccentricity-related fault harmonics between the stator voltage and current, and points out that monitoring only the stator current is insufficient. When the motor is supplied by a vector-controlled drive, both voltage and current become modulated signals and contain fault harmonics. Either stator voltage or current can contain larger fault harmonics due to the influence of the drive controllers and the mechanical load. Therefore, a combination of monitoring both variables is necessary to ensure good detection reliability. Furthermore, with an AC drive, the motor speed and load will change widely, which changes fault harmonics too. A new detection scheme using an artificial neural network is proposed to incorporate the influence of changing operating conditions into the fault detection. This detection scheme is more reliable and cost efficient. In addition, a new off-line non-invasive eccentricity detection method is proposed by using the surge test. Simulation and experiments are conducted to validate the feasibilities of the proposed detection schemes.

This dissertation presents design and implementation of continuous time analog filters for two specific applications: wideband analog systems such as disk drive channel and low-power wireless applications. Specific focus has been techniques that reduce the power requirements of the overall system either through improvement in architecture or efficiency of the analog building blocks. The first problem that this dissertation addresses is the implementation of wideband filters with high equalization gain. An efficient architecture that realizes equalization zeros by combining available transfer functions associated with a biquadratic cell is proposed. A 330MHz, 5th order Gm-C lowpass Butterworth filter with 24dB boost is designed using the proposed architecture. The prototype fabricated in standard 0.35um CMOS process shows -41dB of IM3 for 250mV peak to peak swing with 8.6mW/pole of power dissipation. Also, an LC prototype implemented using similar architecture is discussed in brief. It is shown that, for practical range of frequency and SNR, LC based design is more power efficient than a Gm-C one, though at the cost of much larger area. Secondly, a complementary current mirror based building block is proposed, which pushes the limits imposed by conventional transconductors on the powerefficiency of Gm-C filters. Signal processing through complementary devices provides good linearity and Gm/Id efficiency and is shown to improve power efficiency by nearly 7 times. A current-mode 4th order Butterworth filter is designed, in 0.13um UMC technology, using the proposed building. It provides 54.2dB IM3 and 55dB SNR in 1.3GHz bandwidth while consuming as low as 24mW of power. All CMOS filter realization occupies a relatively small area and is well suited for integration in deep submicron technologies. Thirdly, a 20MHz, 68dB dynamic range active RC filter is presented. This filter is designed for a ten bit continuous time sigma delta ADC architecture developed specifically for fine-line CMOS technologies. Inverter based amplification and a common mode feedback for such amplifiers are discussed. The filter consumes 5mW of power and occupies an area of 0.07 mm2.

In this thesis, a technique for the motion of parallel manipulators through drive singularities is investigated. To remedy the problem of unbounded inverse dynamics solution in the neighborhood of drive singularities, an inverse dynamics controller which uses a conventional inverse dynamics control law outside the neighborhood of singularities and switches to the mode based on the formerly derived modified equations inside the neighborhood of singularities is proposed. As a result, good tracking performance is obtained while the actuator forces remain within the saturation limits of the actuators around singular configurations.

This thesis, for the first time in literature, introduces a comprehensive study about analog controller designs for MEMS vibratory gyroscopes. A controller of a MEMS gyroscope is mandatory for robust operation, which is insensitive to sensor parameters and ambient con- ditions. Errors in the controller design not only deteriorate transient performance, such as settling time and overshoot, but also cause performance degradation due to stability problems. Accordingly, true controller design for a gyroscope is critical work in terms of functionality and system performance. This thesis gives details for modeling, analysis of closed-loop sys- tems, and design procedure for drive and sense modes. Controller loops are implemented both with discrete components and in a CMOS technology as an integrated circuit. Simulation and test results verify the modeling, analysis, and design procedure discussed in this thesis. Drive mode system developed previously at METU is optimized by taking circuit imperfec- tions into account, which results in an improved transient performance of 50 msec settling time with no overshoot for a 4&mu / m drive mode oscillation amplitude. This system has a 60 phase margin with the help of the pole-zero cancellation technique. In addition, a new gener- iv ation and simple drive mode controller for tactical grade applications is designed and verified with a moderate transient performance. Two different sense mode controller design procedures are also developed according to a new base-band equivalent model derived for mismatch operation, as a new contribution to the literature. Firstly, a PID controller is designed for low frequency separation between the drive and sense modes of the gyroscope. Secondly, an integral controller is used for moderate and high mismatch amount. The controller system designed with the new base-band equivalent model improves the linearity, angle random walk, and bias instability by factors of 4, 9, and 3, respectively. Proposed drive and sense mode controllers are also designed and implemented using a 0.6&mu / m standard CMOS process. These chips are the first functional chips developed at METU de- signed for MEMS gyroscopes. Functionality of the proposed three systems, i.e., conventional drive mode controller, new generation drive mode controller, and sense mode controller, are verified with tests. The first prototypes result in 0.033 degree/sqrt/(hr) angle random walk and 3 degree/hr bias instability for open-loop operation, which is very promising and can be improved even further in future designs.

Abstract: This paper presents the results of an experimental investigation into the application of inverter-based variable speed drives to positive displacement rotary compressors. Designs and implements a DSP-microprocessor based of an inverter drive for high-efficiency compressor used in air conditioner. We control the compressor with sine PWM and V/F scheme. Permanent magnet synchronous motor has potential for energy saving in general applications on compressor drives. Permanent magnet synchronous motor drives are used for applications like compressors¡Awhere high dynamic performance is not a demand¡Asimple V/F control strategies may be sufficient to obtain the required control performance. For energy saving to find the best control strategy for an inverter drive for high efficiency compressor used in air conditioner.