RF Modelling and Characterization of Tyre Pressure Sensors and Vehicle Access Systems

Core topics of the work are the vehicle access systems such as PAssive Start and Entry (PASE), Remote Keyless Entry (RKE) as well as Tyre Pressure Monitoring System (TPMS). Two goals are followed: the development of antennas and functionality analysis from RF (Radio Frequency) point of view and improvement of system parts. The overall objective of this work is to advance the state-of-the-art vehicular electromagnetic simulation taking into account the vehicle body and nearest surroundings

The Modelling Of Tyre Rotation Behaviour With Tyre Pressure Monitoring System

The number of motorized vehicles is rapidly increasing in the technology driven countries, and led to the dramatic increase in road accident. The causes of accidents can be categorized into three major factors which are road environmental condition, human behaviour, and vehicle defects. The vehicle defects are the only parameter that is controllable when compared with to other two factors. Statistics show that the tyre and wheels-related from motorcycles is the critical reason and major contributor to road death accident. Therefore, there is the necessity to build a system that is able to monitor the on-road tyre condition. Several existing monitoring systems are available, but each has its own advantages and disadvantages based on the application’s limitation. For example, the important parameter such as pneumatic pressure captured from the tyre is not in real-time, thus it may become worst when there is air leakage. Besides that, tyre rotation behaviour such as acceleration, deceleration and sharp brake condition is not considered which may tend to build up heat. Especially in the countries on the equator which have warm road pavement throughout the daytime. In addition, the placement of transceiver for wireless communication need to determine in order to avoid misinterpretation on the wrong/delayed result captured. The research objective is to develop a monitoring system that combines the advantages of direct and indirect measurement system in order to overcome the problem as discussed. The system needs to capture the real-time pressure level on running tyre and provide calculations on the total distance travelled by the vehicle through algorithms from investigation of tyre rotation behaviour. Apart from that, the power level parameter was studied through the received signal strength index (RSSI) calibration for transmission quality purposes. The system consist of two parts which are the transmitter module and receiver module. The transmitter module is built from combination of hardware such as microcontroller, bluetooth module and sensing devices which sat on the tyre rim to acquire tyre condition. Whereas, the receiver module is responsible to collect and analyze information from the transmitter module and provide a feedback whenever an abnormal tyre condition occurred. Several experiments were conducted, the result shows that the placement of transceiver can be justified with consistent RSSI at -70 dBm from different tyre rotation speed and different transmitter’s directions with the same displacement. The result also shows that the performance of tyre rotation behaviour is able to identify and provide the estimation of distance travelled by the vehicle with evidence support from distance travel calculation. Lastly, the pneumatic pressure level inside the tyre was captured and the result accuracy is further ensured with reversed engineering method with ± 20 kpa from project tolerance. Overall, the research work is able to capture the real-time pressure level on running tyre, provide calculation on total distance travelled based on tyre rotation cycle and position the transceiver based on the power level parameter to ensure the transmission quality

Effects of errorless learning on the acquisition of velopharyngeal movement control

Session 1pSC - Speech Communication: Cross-Linguistic Studies of Speech Sound Learning of the Languages of Hong Kong (Poster Session)The implicit motor learning literature suggests a benefit for learning if errors are minimized during practice. This study investigated whether the same principle holds for learning velopharyngeal movement control. Normal speaking participants learned to produce hypernasal speech in either an errorless learning condition (in which the possibility for errors was limited) or an errorful learning condition (in which the possibility for errors was not limited). Nasality level of the participants’ speech was measured by nasometer and reflected by nasalance scores (in %). Errorless learners practiced producing hypernasal speech with a threshold nasalance score of 10% at the beginning, which gradually increased to a threshold of 50% at the end. The same set of threshold targets were presented to errorful learners but in a reversed order. Errors were defined by the proportion of speech with a nasalance score below the threshold. The results showed that, relative to errorful learners, errorless learners displayed fewer errors (50.7% vs. 17.7%) and a higher mean nasalance score (31.3% vs. 46.7%) during the acquisition phase. Furthermore, errorless learners outperformed errorful learners in both retention and novel transfer tests. Acknowledgment: Supported by The University of Hong Kong Strategic Research Theme for Sciences of Learning © 2012 Acoustical Society of Americapublished_or_final_versio

Elastic wave measurement in rock engineering

Imperial Users onl

RF techniques for IEEE 802.15.4: circuit design and device modelling

The RF circuitry in the physical layer of any wireless communication node is arguably its most important part. The front-end radio is the hardware that enables communication by transmitting and receiving information. Without a robust and high performance front-end, all other higher layers of signal processing and data handling in a wireless network are irrelevant. This thesis investigates the radio circuitry of wireless-networked nodes, and introduces several proposals for improvement. As an emerging market, analysis starts by examining available and ratified network standards suitable for low power applications. After identifying the IEEE 802.15.4 standard (commercially known as ZigBee) as the one of choice, and analysing several front-end architectures on which its transceiver circuitry can be based, an application, the Tyre Pressure Monitoring System (TPMS) is selected to examine the capabilities of the standard and its most suitable architecture in satisfying the application’s requirements. From this compatibility analysis, the most significant shortcomings are identified as interference and power consumption. The work presented in this thesis focuses on the power consumption issues. A comparison of available high frequency transistor technologies concludes Silicon CMOS to be the most appropriate solution for the implementation of low cost and low power ZigBee transceivers. Since the output power requirement of ZigBee is relatively modest, it is possible to consider the design of a single amplifier block which can act as both a Low Noise Amplifier (LNA) in the receiver chain and a Power Amplifier (PA) on the transmitter side. This work shows that by employing a suitable design methodology, a single dual-function amplifier can be realised which meets the required performance specification. In this way, power consumption and chip area can both be reduced, leading to cost savings so vital to the widespread utilisation of the ZigBee standard. Given the importance of device nonlinearity in such a design, a new transistor model based on independent representation of each of the transistor’s nonlinear elements is developed with the aim of quantifying the individual contribution of each of the transistors nonlinear elements, to the total distortion. The methodology to the design of the dual functionality (LNA/PA) amplifier starts by considering various low noise amplifier architectures and comparing them in terms of the trade-off between noise (required for LNA operation) and linearity (important for PA operation), and then examining the behaviour of the selected architecture (the common-source common-gate cascode) at higher than usual input powers. Due to the need to meet the far apart performance requirements of both the LNA and PA, a unique amplifier design methodology is developed The design methodology is based on simultaneous graphical visualisation of the relationship between all relevant performance parameters and corresponding design parameters. A design example is then presented to demonstrate the effectiveness of the methodology and the quality of trade-offs it allows the designer to make. The simulated performance of the final amplifier satisfies both the requirements of ZigBee’s low noise and power amplification. At 2.4GHz, the amplifier is predicted to have 1.6dB Noise Figure (NF), 6dBm Input-referred 3rd-order Intercept Point (IIP3), and 1dB compression point of -3.5dBm. In low power operation, it is predicted to have 10dB gain, consuming only 8mW. At the higher input power of 0dBm, it is predicted to achieve 24% Power-Added Efficiency (PAE) with 8dB gain and 22mW power consumption. Finally, this thesis presents a set of future research proposals based on problems identified throughout its development