Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 76-80).

Thesis (M.A.)--York University, 2000. Graduate Programme in Film and Video. / Typescript. Includes bibliographical references (leaves 114-117). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ67715.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

The thesis project is aimed to automate ultrasonic Time-of-Flight (ToF) technique for saw log classification using signal processing. The ToF technique works in such a way that ultrasonic tone-burst pulses are sent into a saw log, and then the ToF that the pulses take for the propagation is measured and used to calculate the sound speed and further, the Modulus of Elasticity (MoE). Based on the MoE, the quality of the logs is predicted and presorted before sawing. Development of matched filters is the central task for automating the ToF technique.  The whole project was carried out in two different parts: 1) Fundamentals and MATLAB implementation, and 2) Real-time implementation based on digital signal processor.     In the first part, fundamentals on the ToF technique and matched filters have been studied, and then MATLAB simulations of matched filters for automating the technique have been made. After this, test measurements have been conducted. The test results are shown to be consistent with the simulation: matched filtering works well for automating the ToF technique. In the second part of the report, an embedded algorithm has been developed and implemented on a Digital Signal Processor. The algorithm is the first step in the automation of measurements. Eventually, two test measurements have been performed with the DSP. The results were obtained using both oscilloscope to visualize and MATLAB to plot the obtained debug log, and they have shown that the algorithm works, and can automatically measure the ToF, which is in turn used to calculate the sound speed and MoE. The further work on the project that needs to be done, is to applying the developed system to the real situations in sawmills, and improving it according to their requirements.

The neural basis of the brain's ability to represent time, which is an essential component of cognition, is unknown. Despite extensive behavioral and electrophysiological studies, a theoretical framework capable of describing the elementary neural mechanisms used by biological neural networks to learn temporal representations does not exist. It is commonly believed that the underlying cellular mechanisms reside in high order cortical regions and there is an ongoing debate about the neural structures required for temporal processing. Recent experimental studies report sustained neural activity that can represent the timing of expected reward in low-level primary sensory cortices, suggesting that temporal representation may form locally in sensory areas of the cortex. This thesis proposes a theoretical framework that explains how temporal representations of the type seen experimentally can be encoded in local cortical networks and how specific temporal instantiations can be learned through reward modulated synaptic plasticity. The proposed framework asserts that the mechanism responsible for encoding the observed temporal intervals is long-term synaptic potentiation between neurons in a recurrent network. Analytical and numerical techniques are used to demonstrate that the model is sufficient to allow näive networks of both linear and non-linear neurons to encode and reliably represent durations specified by external cues during a training period. Analysis of a non-linear spiking neuron model is accomplished using a mean-field approach. The form of temporal learning described has specific implications that can be confirmed experimentally and these predictions are highlighted. Experimental support for a central component of the model is presented and all of the the results are discussed in relation to current experimental and computational work. / text

Coordinated Universal Time (UTC) is the standard civil time scale available via time signals in use in most parts of the world today. Leap seconds are the means to keep civil time, or UTC, aligned with adjusted Universal Time (UT1), a time based on Earth rotation corrected for polar variation. They are intentional adjustments to UTC that are instituted to prevent the difference between UT1 and UTC from exceeding +/- 0.9 seconds, based upon international agreement. Over a decade ago various technical communities for whom a continuous time scale would be more suitable than UTC, as disseminated in real-time, currently provides began making a case that the definition of UTC should be changed to eliminate leap seconds as a way to specify time unambiguously. This issue was discussed at the 2012 World Radiocommunications Conference (WRC), but consensus for elimination of the leap second was not achieved and a decision was postponed until the 2015 WRC. This report examines the leap second debate by summarizing general concepts of time and basic aspects of the leap second, followed by a discussion of non-technical considerations, technical aspects, and possible solutions. / text

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

In financial markets, transaction durations refer to the duration time between two consecutive trades. It is common that more frequent trades are expected to be followed by shorter durations between consecutive transactions, while less frequent trades are expected to be followed by longer durations. Autoregressive conditional duration (ACD) model was developed to model transaction durations, based on the assumption that the expected average duration is dependent on the past durations. Empirically, transaction durations possess much longer memory than expected. The autocorrelation functions of durations decay slowly and are still significant after a large number of lags. Therefore, the fractionally integrated autoregressive conditional duration (FIACD) model was proposed to model this kind of long memory behavior. The ACD model possesses short memory as the dependence of the past durations will die out exponentially. The FIACD model possesses much longer memory as the dependence of the past durations will decay hyperbolically. However, the modeling result would be misleading if the actual dependence of the past durations decays between exponential rate and hyperbolic rate. Neither of these models can truly reveal the memory properties in this case. This thesis proposes a new duration model, named as the hyperbolic autoregressive conditional duration (HYACD) model, which combines the ACD model and the FIACD model into one. It possesses both short memory and long memory properties and allows the dependence of the past durations to decay between the exponential rate and the hyperbolic rate. It also indicates whether the dependence is close to short memory or long memory. The model is applied to the transaction data of AT&T and McDonald stocks traded on NYSE and statistically positive results are obtained when it is compared to the ACD model and the FIACD model. / published_or_final_version / Statistics and Actuarial Science / Master / Master of Philosophy

This dissertation undertakes a comprehensive analysis of the arguments for and against an ontology of momentary temporal parts advanced by a long tradition of Buddhist philosophers in Sanskrit. Drawing on the latest authors in Indian Buddhist schools and using contemporary tools and theories, I defend the Buddhist ontology against the best objections of its Naiyāyika critics, who favor an ontology of enduring substances. The dissertation has six chapters. In the first, I provide an overview of epistemology and ontology in the classical period of Indian civilization. In the second, I discuss how the competing considerations of change and endurance shape the early arguments for and against momentariness. The relationship of properties to property-bearers and of parts to wholes emerges as the central point of contention. In the third chapter, I consider the Buddhist argument that destruction is uncaused. Here the ontological status of absences becomes the crucial issue, and I explain the complex exchanges on this score. In the fourth chapter, I examine the most sophisticated of the Buddhist arguments, an inference based on the thesis that anything that exists has causal efficiency. Causal relations also play a key role in the Buddhist account of the persistence of things as presupposed in everyday discourse. The topic of the unity of a series is continued in the fifth chapter, where I apply Buddhist ideas to the problem of personal identity. Here so-called recognition, our identifying an object as in some sense the same as one previously perceived or cognized, is seen to be the key consideration according to my reconstruction of the classical debate. Especially cross-sensory recognition, seeing now something that one has previously touched, for instance, becomes the central issue. I defend the Buddhist view by giving an account of cross-sensory recognition that countenances no non-momentary entities. In the sixth chapter, I put the Indian dispute into the context of contemporary debates over temporal parts theories. A partial translation of the previously untranslated text, the Kṣaṇabhaṅgasiddhi of Ratnakīrti (an eleventh-century author who may be counted the last of the great Indian Buddhist philosophers), forms an appendix. / text

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