Thesis--M. Phil., University of Hong Kong.

No description available.

A novel CMOS operational transconductance amplifier (OTA) is proposed and demonstrated in this thesis. Due to its feedforward-regulated cascode topology, it breaks the previous OTA frequency limit of several hundred MHz and operates at frequencies up to 10 GHz with a large transconductance. This is confirmed by an in-depth high-frequency analysis, simulations, and experimental demonstrations using purpose-built circuits. Experimental results also show that the proposed OTA has high linearity and low intermodulation distortion, which is of particular interest in microwave circuits. The OTA’s noise behavior and the effects of process variations, device mismatch, and power supply noise on the transconductance are also studied. To the best of our knowledge, the noise analysis here is the first of its kind on regulated cascode circuits, which can be applied to other regulated cascodes with minor changes. Three microwave applications of this OTA are explored in this thesis: 1) an active bandpass filter with a wide tuning range, 2) a 2.4-GHz ISM-band variable phase shifter, and 3) a microwave active quasi-circulator, which are all in CMOS MMIC form. These three circuits can be easily integrated with other chip components for System-on-Chip (SoC) realizations. The use of the OTA makes these three applications super compact: the active filter is at least 5 times smaller than previous circuits with a similar topology, and the phase shifter and quasi-circulator are at least 3 times smaller than previous works in that frequency range. Furthermore, the tunability of the developed OTA on its transconductance gives its applications extra freedom in tuning their frequencies and gains/losses electronically. In the first application, the active bandpass filter has a novel narrowband-filtering topology and has a wide tuning-range of 28% around 1.8 GHz, which makes it very suited for reconfigurable multi-band wireless systems. In the second and third applications, the active variable phase shifter has a comparable variable phase shift range of 120º in the 2.4-GHz ISM band and the active quasi-circulator has transmissions close to 0 dB and directivities over 24 dB from 1.5 GHz to 2.7 GHz. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2008-09-18 09:49:00.07

This thesis investigates the representation of operational decision makers within simulation modelling. Artificial Intelligence concepts, such as expert systems focus on the problem of representing, in high-level code, complex real-world decision making problems. The author therefore proposes that the use of expert system technology may provide an improved means of representing operational decision tasks and that as a consequence, apriori possibilities may exist in the context of model experimentation based on alternative operational policies. The thesis further investigates the nature of operational decision making and the potential need to represent within a model, inter-dependencies between decision makers. A prototype system called ESSIM is developed which comprises of two interlinked components, a discrete event simulation module and expert system module. The benefits of the proposed approach are then assessed by comparing the functionally of ESSIM with conventional modelling techniques. The comparison is carried out by developing three alternative models of an automated container port, one of these using ESSIM. Experiments were then devised and executed which seek to draw conclusions on the thesis proposal.

No description available.

No description available.

The world of operational police command is a challenging and complex one, where significant command decisions need to be made amid uncertainty and within narrowing time-frames. The consequences attached to these decisions can often be far reaching and have been in some cases grave, as in the case of disasters such as those at Bradford and Hillsborough football stadia. Accordingly, there is a pressing need to instil within key command officers, the skills and the experience necessary to make these bold and effective command decisions, but within an environment where such dire Consequences (as those that follow a disaster) do not arise from mistakes or inadequacy. The question then becomes how to create such an environment which is at the same time both safe and sufficiently realistic to provoke similar decisional reactions to those that would occur at a real event. Even if this was achievable a further stage would be necessary in which such learning came to be transferred back into an operational command situation. This thesis explores in a systemic way the design, implementation, testing, modification and re-testing of a critical incident management command simulator whose central tenet was to create an immersive simulation that, by virtue of its high degree of fidelity, was capable of engendering experience of the management of critical incidents for a target population comprising senior police command officers. From tentative beginnings to its operational installation as a fully functional command training simulator, this thesis maps out the key development decisions which were informed by the findings of a series of trials, observations, interviews, surveys and physiological measurements. At the same time, it describes the theoretical models used to explain the relationships between and functionality of the system and its individual components, whilst exploring the dimension of human computer interaction. This is action research in that the findings it generated led to an incremental series of modifications to what became an operational training simulator (named MINERVA) on which useful and transferable command training actually took place.

iii, 114 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pure Mathematics, 1976

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references and index.

Zugl.: Frankfurt (Main), Univ., Diplomarbeit, 2004