Filters
Availability
Publication Year
Resource Type
Faculty
School/Institute
Publication Search Results
Sort
Results per page
1 - 10 of 47
-
(2007)Conference PaperThis work presents the derivation of a comprehensive mathematical model for an off-road vehicle such as an agricultural tractor that drags behind it a heavy implement. The models are being developed with the aim of designing robust controllers that will enable the high precision control of the implement’s trajectory. The developed model is subjected to real conditions, such as ground undulation and uncertainty, sloping terrain, tyre slippage, and constrained steering of the tractor. The implement is assumed to possess independently steered wheels for aiding in implement alignment. A complete model is presented and simulated under varying conditions. Primarily this work demonstrates and validates the trailed vehicle system behavior when the trailing implement is subjected to large drag forces due to ground engagement and the significantly large lateral disturbances that occur in real life broad acre farming conditions.
-
(2007)Conference PaperGPS timing receivers have long been relied upon by various communications networks for achieving synchronization among the network nodes. Cellular networks, particularly CDMA cellular networks, actively employ GPS timing receivers for making their time critical decisions, particularly handoff. Operations and parameters which set the network quality of service (QoS) require that these GPS receivers provide timing solution up to nano-second accuracy. Therefore, GPS timing receiver are required to provide a disturbance free solution. However, as all GPS receivers communicate with GPS satellites over the air interface; these are inevitably vulnerable to RF interference. This interference disturbs the timing receiver¿s performance, degrading its solution. This paper appreciates this issue, identifies the problems caused and discusses in detail the performance degradations of cellular networks due to instability of timing signals from GPS.
-
(2001)Conference PaperThis paper reports a simple technique to induce second order nonlinearity in doped electro-optic polymer optical fibre through direct electric poling. The nonlinear effect is measured through a simple yet highly accurate and sensitive transverse modulation scheme. Experimental results show that liquid crystal has the highest electro-optic effect among different nonlinear dopants. Some of the applications are briefly discussed.
-
(2006)Conference PaperDistributed feedback fibre laser based hydrophone systems have great potential for high sensitivity underwater acoustic detection. Here we report on recent progress in our research and development of distributed feedback fibre laser hydrophone systems. We discuss the system configuration as well as sensor design, fabrication and packaging for high acoustic pressure sensitivity. In particular we report the significant performance improvement achieved in our experimental investigations.
-
(2006)Conference PaperIn the following paper is presented an investigation of a composite cavity fibre laser with active feedback cavity. By employing strong-reflection and active feedback cavity, an in-housee fabricated 12cm long composite cavity fibre laser was able to sustain single longitudinal mode operation at 60uW without mode hopping
-
(2006)Conference PaperFibre Bragg grating (FBG) sensors are used for the experimental investigation of two of the most important time-dependent properties of concrete: drying shrinkage and creep. A swept wavelenght system is used as the interrogation technique. The FBG sensors are embedded directly into structural grade concrete specimens. Standard mechanical method is used in parallel with embedded FBG sensors. Both mechanically and optically measured time-dependent strains are discussed. It is shown that the FBG sensors offer a better alternative to the conventional electrical and mechanical methods, in the measurement of long-term time-dependent strains.
-
(2006)Conference PaperWavelet analysis is applied extensively to a multiplexed fibre Fizeau interferometer and fibre Bragg grating sensor system. Specifically, the discrete wavelet transform is used to demodulate the multiplexed sensor signal simultaneously; and two wavelet denoising methods are used to reduce the noise present in the signal and measurands record. Experimental demonstration is performed through the simultaneous measurement of quasi-static and temperature.
-
(2005)Conference PaperAn improved algorithm is proposed to demodulate signals from a spatial-frequency multiplexed fibre-optic Fizeau strain sensor system. We have demonstrated that this algorithm, which includes wavelet signal-processing techniques, reduces noise and increases strain resolution.
-
(2005)Conference PaperThe newly built bridge made of novel reactive powder concrete at Shepherd's Creek, Lake Macquarie, NSW is tested for static strain activity over a two-day period. We developed a fibre grating-based experimental strain sensing system and employed an active interrogation scheme using a tuneable laser source. Four FBG sensor heads are surface-mounted in the middle of a girder and under the bridge deck to monitor the strain and temperature movement. The strain sensors have a resolution of approximately 1.5. The observed strain fluctuations, which indicate the hogging and sagging behaviour of the bridge, are in agreement with the theoretical expectation.
-
(2005)Conference PaperHere we present our investigation into the use of a distributed feedback fibre laser (DFBFL) as an intensity-modulated sensor. In our preliminary experiments, we demonstrated the construction of this simple intensity fibre acoustic sensor system and attianed good sensitivity.
- 1 (current)
- 2
- 3
- 4
- 5