Thesis (Ph. D. in Psychology)--Vanderbilt University, Aug. 2005. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 181-206).

Thesis (M.Soc.Sc.)--University of Hong Kong, 1987. / Also available in print.

The emergence of robots as essential components in the development of flexible manufacturing systems has created a demand for measurement techniques capable of measuring their performance. Typically it is required to measure the position of the robot end effector at speeds of up to 5 m/sec in a 1 metre sided cube and with a precision better than 0.1 mm. An instrument has been developed that uses a laser tracking technique and the principle of triangulation to determine the x,y and z co-ordinates of an optical target. It consists of two identical sub-systems, a retroreflective cat's eye target and a supervisory microcomputer. Each sub-system aims a low power laser beam at the target and detects the retroreflected beam for feedback to the mirror actuators controlling the beam direction. The instrument has been modelled, calibrated and evaluated. The effect on the target coordinate calculation of various system errors has been studied and a variety of measurement tools and methods are presented to calibrate the instrument both at component and sub-system level and also as a final system. The design of the cat's eye target is reviewed and a method of manufacture presented. Preliminary results and design details of a new optical sub-system with up-graded characteristics are also included. Tests show that the present instrument has a measurement accuracy of 0.03%, a repeatability of 0.01% (all for 1 standard deviation) for a measurement space of approximately one metre cube. The beam steering scanners have a bandwidth in excess of 74 Hz and the tracking velocity is approximately 3 m/s.

Benzodiazepine (BZ) drugs, such as diazepam (Valium®) and chlordiazepoxide (Librium®), are widely prescribed for their sedative/anxiolytic properties but also impair mnemonic processes in both humans and animals. In the Morris water maze, an aversively motivated spatial learning task, BZs impair spatial learning but spare retention/performance. This spatial learning deficit cannot be attributed to sedation, gross sensorimotor impairments, hypothermia, state-dependent learning, or reductions of escape motivation (anxiolysis). The following series of experiments sought to further characterize the neurochemical, neuroanatomical, and electrophysiological substrates of BZ-induced impairments of spatial learning. In Experiment I, the role of endogenous BZs in spatial learning was assessed. The BZ receptor antagonists flumazenil (Ro 15-1788) and CGS 8216, as well as the BZ receptor inverse-agonist β-carboline, enhanced spatial learning in an inverted-U dose-dependent manner, suggesting that endogenously released BZs impede optimal learning. In Experiment II, the role of the BZ ω1 receptor subtype in spatial learning was assessed. CL 218,872, a selective agonist for the BZ ω1 receptor subtype, impaired spatial learning in a dose-dependent and flumazenil-reversible manner, thereby implicating the ω1 receptor subtype in BZ-induced amnesia. Together these results suggest that endogenous BZs activity, like BZ drugs, is detrimental to spatial learning and that specific BZ receptors mediate this impairment. Several neurochemical systems are important for spatial learning in the MWM and arc influenced by BZs. The contributions of two of these neurochemical systems, the opioids and acetylcholine (ACh), to the spatial learning deficit produced by BZs were assessed. In Experiment III, a better understanding of the role of opioid systems in spatial learning was sought. Morphine, a prototypical opioid, impaired spatial learning in a dose-dependent and naloxone-reversible manner. However, morphine also impaired performance and escape to a visible platform and its effects on spatial learning could be attenuated by increasing the escape incentive (colder water). This impairment pattern suggests that morphine impairs spatial learning by reducing escape motivation. Because both BZs and cold water immersion increase endogenous opioid activity, it seemed possible that the combination of drug- and water-induced opioid release might mediate the spatial learning deficit produced by BZs. In Experiment IV, naloxone, an opioid receptor antagonist, completely blocked the spatial learning deficit produced by morphine but failed, even at a higher dose, to block the spatial learning deficit produced by diazepam . Conversely, flumazenil, a BZ receptor antagonist, completely blocked the spatial learning deficit produced by diazepam but failed to affect the amnesic effects of morphine. Together, these findings strongly suggest that the spatial learning deficit produced by BZs is not due to enhanced opioid activity. There is also biochemical evidence that BZs interact with ACh systems. In Experiment V, flumazenil attenuated the spatial learning deficit produced by scopolamine, an ACh (muscarinic) antagonist, but physostigmine, an acetylcholinesterase inhibitor, failed to attenuate the spatial learning deficit produced by chlordiazepoxide, even at doses that completely reversed the spatial learning deficit produced by scopolamine. Together these results fail to support the notion that BZs impair spatial learning by reducing ACh activity but suggest that scopolamine impairs spatial learning by enhancing endogenous BZ activity. Several neuroanatomical regions possess a high density of BZ receptors and are also integral for spatial learning in the MWM. In Experiment VI, infusions of chlordiazepoxide into the medial septum, but not frontal cortex, nucleus basalis magnocellularis, amygdala, hippocampus, or cerebellum, impaired spatial learning but had little effect on anxiety. Conversely, infusions of chlordiazepoxide into the amygdala reduced anxiety but had little effect on spatial learning. These results suggest that the medial septum mediates the amnesic effects of BZs and that the amygdala mediates the anxiolytic effects. In Experiment VII, intraseptal infusions of chlordiazepoxide were additionally found to impair spatial learning in a dose-dependent and flumazenil-reversible manner. However, infusions of flumazenil into the medial septum failed to block the amnesic effects of systemically administered chlordiazepoxide, suggesting that the amnesic to effects of BZs are not mediated by the medial septum exclusively. Tetrahydroaminoacridine, an acetylcholinesterase inhibitor, failed to attenuate the spatial learning deficit produced by intraseptal infusions of chlordiazepoxide, suggesting that the deficit was not due to a disruption of the septohippocampal ACh projection. Together, these results suggest that chlordiazepoxide impairs spatial learning by interacting with the septohippocampal GABAergic projection. The septohippocampal GABAergic projection regulates the excitability of hippocampal afferents (e.g., perforant path). Experiment VIII assessed the effects of systemically administered BZs on the induction of long-term potentiation (LTP) in the perforant path. CL 218,872, but not chlordiazepoxide or diazepam , significantly suppressed long-term potentiation. However, all drugs impaired spatial learning. These findings suggest that CL 218,872 impairs spatial learning by suppressing LTP but that BZ-induced spatial learning deficits can occur in the absence of perforant path LTP suppression. Taken together, the above results suggest that endogenous BZ systems, particularly those in the septohippocampal system, are important modulators of mnemonic processes. These findings are discussed in the context of understanding information storage processes and the implications for clinical populations. / Graduate

This study used the process dissociation procedure to investigate the effects of three variables on conscious and unconscious influences of memory for object location. The purpose was not only to provide insight into conscious and unconscious influences of memory for object location, but also to obtain support for the assumption that the two influences operate independently. Such support can be obtained by demonstrating that a manipulation affects one component of memory but leaves the other invariant. The three variables used in the present study included dividing attention at study and test, the age of the participants, and habit strength. In the first experiment, when attention was divided at study, the conscious estimate was significantly reduced under conditions of divided attention. This result was also found when attention was divided at test, although the effect only approached significance. Moreover. when attention was divided at study, there was a tendency for the unconscious estimate to be greater under full attention than under divided attention. When attention was manipulated at test, however, the unconscious estimate did not vary across the two attention conditions. The results of Experiment 1, therefore, did not provide strong evidence for the assumption of independence. Such evidence, however, was obtained in Experiments 2 and 3 where a double dissociation between conscious and unconscious influences of memory for object location was observed. Specifically, in Experiment 2 it was found that age affected the conscious component but left the unconscious component invariant, whereas in Experiment 3 it was found that manipulating habit strength affected the unconscious influence of memory for spatial location but not the conscious influence. The results of these experiments are discussed in terms of their importance for research on memory and aging and systems theories of memory, as well as for the assumption that conscious and unconscious influences of memory operate independently. / Graduate

No description available.

No description available.

Spatial Modulation (SM) is a spatial multiplexing technique designed for MIMO systems where only one transmit antenna is used at each time. It is considered to be an attractive choice for future wireless communication systems as it reduces Inter Channel Interference (ICI) while maintaining high energy efficiency. It can achieve this goal by mapping block of data bits into constellation points in the spatial and signal domain. Combining this innovative method with multiple access techniques could improve the system performance and enhance the data rate. In Code Division Multiple Access (CDMA) method employing parity bit permutation spreading, the bit error rate (BER) performance could be improved by using the parity bits to select the spreading sequence to use at each signalling interval. In this thesis, a new system model based on SM and CDMA employing parity bit permutation spreading is proposed and investigated. The proposed system takes advantage of the benefits of both techniques. In this system, in addition to use the parity bits to select the spreading sequences, same concept is used to select the combination of antennas to activate at each time instant. By doing so, a reduction of power consumption, Inter-Channel and Inter Symbol Interference effect can be achieved while keeping a certain diversity order compared to SM. Multiuser scenario is also discussed in order to investigate the multiple access interference (MAI) effects in synchronous transmission. In such case, the receiver estimates the desired user's information by considering the other users' signal as additional noise. Simulation results of the proposed MIMO-CDMA system employing permutation spreading show, for single user and multiuser, a significant improvement of the BER performance in low signal to noise ratio (SNR) when SM is implemented.

Sustainable development has attracted attention from both English and Korean planning systems. Whilst embracing this concept within planning, both countries have attempted to reform their local plan-making systems to flexibly respond to changing circumstances. This similarity of direction towards reformation of the planning sector raises questions for this research. Given that England embarked on promoting sustainability within its plan-making system ahead of Korea and reforming its planning system in the same direction as Korea, there may be a possibility that the current English planning system shows how far Korea can progress in the pursuit of a more environmentally sustainable planning system in the future.With this in mind, the research deals with two domains: understanding the environmental sustainability of the local plan-making systems in the two countries and discussion of the transferability of the lessons extracted from the comparative analysis. The findings reveal that many of the lessons learnt from the English experience could be adaptable in a Korean context under the existing legislation and that an amendment of national directives, in particular, Directive on Urban Planning could expand transferability. For instance, by designing the process of community participation and integration in greater detail in the Directive and suggesting detailed process of strategic environmental assessment as in the English system, there is a greater possibility for the local plan-making system in Korea to support environmental sustainability within planning more substantially. Together with this, findings on transferability anticipate that a potential conflict could exist due to the financial and administrative burden which may be imposed on local planning. Furthermore, the consensual knowledge held by actors involved in the plan-making process could facilitate the transferability of the suggested lessons. However, the current Korean politics which is focused on economic concerns surrounding the reformation of the plan-making process could create potential obstacles in accomplishing the suggested lessons.