京都大学 / 新制・課程博士 / 博士(地域研究) / 甲第23305号 / 地博第286号 / 新制||地||110(附属図書館) / 京都大学大学院アジア・アフリカ地域研究研究科アフリカ地域研究専攻 / (主査)准教授 佐藤 宏樹, 教授 山越 言, 准教授 安岡 宏和 / 学位規則第4条第1項該当 / Doctor of Area Studies / Kyoto University / DGAM

Les systèmes de production et de sûreté de fonctionnement sont d'une importance majeure dans l'industrie des procédés. Leurs performances impactent directement les intérêts de l'industrie. Ces systèmes ont des comportements similaires. Ces comportements peuvent être conceptualisés dans des modèles via des patterns de modélisation. La réutilisation de ces patterns permet de rendre le processus de modélisation à la fois simplifiée et plus efficace.Dans cette thèse, nous proposons un ensemble varié de patterns de modélisation. Ils sont classés en fonction de leur usage, ce qui reflète le fonctionnement d'un pattern de modélisation. Les patterns sont présentés sous forme d’un catalogue. Sur la base de l'étude de nombreux systèmes de production et de sécurité, vingt-quatre (24) patterns de modélisation sont introduits. Chaque pattern est représenté par un ensemble d'éléments structurés. Nous proposons une méthodologie basée sur les patterns pour l'analyse des performances des systèmes de production et de sûreté de fonctionnement.Pour tester la pertinence des patterns de modélisation suggérés, nous avons mené des études expérimentales sur un ensemble de systèmes de production et de sûreté. Tous les systèmes de validation sont extraits de la littérature. Ces systèmes traitent la majorité des difficultés de modélisation détectées auparavant. Une comparaison est effectuée entre les résultats obtenus en utilisant la modélisation basée sur les patterns et ceux rapportés dans la littérature. / Production and safety systems are crucial in the process industry. Their performances affect significantly the industry interests. These systems have common behaviors. Such behaviors can be captured in models via modeling patterns. By reusing modeling patterns, the modeling process can be simplified and made more efficient.In this thesis, we propose a versatile set of modeling patterns. They are classified according to their purpose, which reflects what a modeling pattern works for. Modeling patterns are exhibited as a catalog. Based on reviewing numerous production and safety systems, twenty-four (24) modeling patterns are introduced. Each pattern is illustrated with a set of structured items. We propose a pattern-based methodology for performance analysis of production and safety systems.To test the applicability of proposed modeling patterns, we conducted experimental studies on a set of production and safety systems. All systems are extracted from the literature. These systems are declared to cover most of modeling difficulties. Comparisons are performed between the results obtained using modeling patterns and those reported in the literature.

While people sleep, the brain replays the same neural firings that resulted from waking activities that day. This results in greater memory strength following a sleeping delay than a waking delay. The current project built upon this fact in a series of three experiments. Experiment 1. Although previous research has demonstrated a benefit of sleep to memory strength, the literature has not established the impact of sleep on memory specificity. Computational models of medial temporal lobe function posit that discrimination and generalization across similar memories are accomplished through processes known as pattern separation and pattern completion, respectively. To discover whether sleep predisposes people toward pattern separation or pattern completion, participants studied pictures of common objects. After a 12-hour delay, during which participants either slept or stayed awake, participants indicated whether “lure” images were exactly the same or merely similar to those they studied. There was better memory discrimination in those who slept, consistent with a bias toward pattern separation following sleep. Experiment 2. In order to discover whether the pattern of memory demonstrated in Experiment 1 would carry over to semantic memories, participants studied textbook material and took a true/false test 12 hours later. There was a shift in the response trends following sleep, such that participants were more likely to mistakenly endorse highly similar false statements as “true” but were also more likely to correctly endorse more dissimilar false statements as “false.” However, we did not detect evidence of an increased bias toward pattern separation or pattern completion following sleep for this material. Our findings appear consistent with the prediction that memory specificity is benefitted by sleep. Experiment 3. Previous research has demonstrated that memories encoded later in the day are consolidated better than memories encoded earlier in the day. However, these studies have not controlled for the differential decay that memories suffer across these two elapsed periods. In this study, we attempted to show the degree of improvement afforded by sleep using a before-sleep comparison group. However, post hoc analyses revealed a significant interaction between the proposed outcomes and whether participants had napped during the day. These preliminary findings may suggest that napping differentially affects the consolidation of information studied before and after napping.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24186号 / 医博第4880号 / 新制||医||1060(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 中山 健夫, 教授 平井 豊博, 教授 中本 裕士 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

The spatial pattern of plants reflects biotic and abiotic factors, including interactions with surrounding environmental conditions and other plants. Appalachian heath systems are presently understudied regarding spatial point pattern research, despite representing a unique and biologically valuable ecosystem. In this study, we characterized the spatial pattern of three tree species distributions in the upland heath barrens on Cabin Mountain in Canaan Valley, West Virginia through fieldwork, statistical modeling, and the use of geographical information systems (GIS). The research objectives were to: 1) quantify the global and local spatial patterns of trees to infer biotic process, and 2) identify how tree spatial pattern varies with selected biophysical variables, including ground curvature and topographic wetness index, to understand potential relationships between ambient conditions and spatial pattern. The spatial statistics, Ripley's K-function and nearest neighbor analysis, presented a series of different interaction types reflected across size-growth classes and species where the null hypothesis was rejected for some pairs and supported in others. The selected biophysical variables had no significant relationship to spatial pattern at the site. These findings suggest a range of both intraspecific and interspecific interactions are taking place in the heath barrens of Cabin Mountain, where significant levels of facilitation are occurring among encroaching red maple and striped maple, while red spruce is in competition with both species of maple, and that relationships are formed outside the influence of topographic characteristics of the site. / Master of Science / The spatial pattern of plants reflects biotic and abiotic factors, including interactions with surrounding environmental conditions and other plants. Appalachian heath barrens are presently understudied in regard to spatial point pattern research, despite representing a unique and biologically valuable ecosystem. In this study, we characterized the spatial pattern of three tree species in the red spruce heath barrens on Cabin Mountain in Canaan Valley, West Virginia through fieldwork, statistical modeling, and the use of geographical information systems (GIS). The research objectives were to: 1) quantify demographics and the spatial pattern of trees to assess for ongoing plant interaction, and 2) understand whether tree spatial pattern is affected by selected biophysical variables, including ground curvature and topographic wetness index, to understand potential relationships between environmental conditions and spatial pattern. The results suggested a range of interactions were occurring across the plot, intraspecies, different species-pairs, and size-growth classes. Most notably, encroaching striped and red maple species, had a positive relationship, while red spruce and both maple species had largely competitive relationships. Both topographic wetness index and ground curvature had no significant relationship to spatial pattern at the site. These findings suggest a range of both intraspecific and interspecific interactions are taking place in the heath barrens of Cabin Mountain, indicating the possibility of conversion from red spruce heath barrens to deciduous forest, that this pattern is formed outside the influence of topographic characteristics of the site.

The stormwater retention pond is a best management practice used for the improvement of runoff water quality before it discharges into larger surface waterbodies. A vortex-type retention pond, called the Nautilus PondTM, is a new design approach for stormwater retention ponds that is expected to produce an internal flow pattern in the pond that is more conducive to removal of sediments from runoff. Since many existing stormwater retention ponds were originally designed only for flood control, most of the ponds are subject to large dead zones, severe short-circuiting and short retention times, which can limit sediment retention in the ponds. In this study, the robustness of the design of the Nautilus PondTM was evaluated by assessing its residence time distribution (RTD) characteristics, flow pattern and sediment deposition patterns under various conditions of flow in the pond. The study was carried out in two physical scale models of a simplified Nautilus PondTM: one with a scale ratio of 1:30.775 for an aspect ratio of 100:2, and the other with a scale ratio of 1:13.289 for a pond of 50:2 aspect ratio. The aspect ratio is the ratio of the pond diameter at its water surface (top width) to the depth of flow, 2 m at corresponding design flow rates, in the pond. First, the RTD characteristics and flow patterns in the ponds were investigated using tracer mass recovery and flow visualization tests allowing different times for steady flow development (flow development time) for the design flows corresponding to 4 m3/s in the 100:2 prototype pond and 1 m3/s in the 50:2 pond. Then, tracer tests were carried out at different flow rates to investigate its effects on the RTD characteristics in both model ponds. The deposition patterns of approximately 50 micron sediment particles (prototype size) were also observed. The best position of a berm around the pond outlet was determined for the 100:2 pond by comparing the RTD characteristics and the sediment deposition patterns in the pond for three different positions of the berm. The residence time distribution characteristics and the sediment deposition pattern were also assessed for the 50:2 pond with a berm placed in a position equivalent to the best position identified in the 100:2 pond tests. It was found that the RTD curves at design flow rates of 4 m3/s and 1 m3/s for different flow development times were very similar to each other for both pond aspect ratios; the flow development time was found to have little effect on the flow characteristics of the ponds. The average baffle factors, short-circuiting indices and Morril dispersion indices were 0.41, 0.20 and 4.1, respectively, for the 100:2 pond aspect ratio, whereas these were 0.23, 0.05 and 8.6 for the 50:2 pond. The flow rate was found to have a significant effect on the RTD characteristics of both ponds. There were multiple peaks in the RTD curves for the lower flow rates tested for the 100:2 pond. This was thought to be a result of the low inflow momentum and high aspect ratio of the pond. As the flow rate was increased, the residence time distribution curve had a single, lower peak. In both ponds, an increase of flow rate caused the baffle factor and short-circuiting index to decrease and the Morril dispersion index to increase indicating that the inflow spent a shorter time in the pond. The sediment deposition pattern tests in both ponds without the berm around the outlet showed that a higher quantity of sediments deposited in the outer peripheral region of 100:2 pond. The 50:2 pond deposited a small amount of sediment along the periphery due to the high velocity inflow jet and lower aspect ratio of the pond. The best position of the berm among those tested was found to be at the 60% of pond bed radius from the center. Though the RTD characteristics for the 100:2 pond with different berm positions were very similar to each other, the 100:2 pond with the berm position at 60% of pond bed radius deposited most of the sediments outside the berm. The RTD characteristics in both ponds showed significant improvement with a berm at the 60% of radius position compared to the ponds without a berm. This improvement was more significant for the 50:2 pond than for the 100:2 pond. Further, the sediment deposition pattern in 100:2 pond with berm at 60% of bed radius showed that the larger sized sediment particles mainly deposited outside the berm and the finer particles deposited inside the berm. The 50:2 pond did not show any significant difference in particle size distribution of the sediments deposited inside and outside of the berm.

Condition based monitoring is widely used for the determination of the health of machines. The Nottingham Trent University Computing Department has developed a new system, the Incremental Motion Encoder (!ME), which is based on the time interpolation of the digital signals produced by an optical encoder. Experiments have shown that the !ME can be used as a condition based maintenance sensor as it is possible to detect rolling element defects, an unbalanced shaft and oil contamination of a bearing. The system uses a geometrically configured optical device to scan a precision encoder disc and Digital Signal Processing technology is used to interpret the signals. Previous work has demonstrated the qualitative usefulness of the 1ME. However, further work was needed to assess the accuracy of the measurements, to analyse the principles of the 1ME, to validate the performance of the existing device and to develop methods for error definition and error compensation. Testing and experimentation on the existing experimental system have been carried out by the Candidate and an understanding gained of the device. The sources of error of the 1ME have been identified, which had not been quantified previously. Measuring and compensating for the three main sources of error, read head position, eccentricity of the encoder disc and encoder abnormalities are the three major tasks of the project. Modifications to the experimental rig have been developed in order to allow these tasks to be addressed. The Candidate has developed three different types of techniques to measure the position error of the read heads. A pattern recognition method was developed and is successful for 1ME systems that use an encoder disc with significant grating line errors. A second method using Fast Fourier Transform (FFT) has been developed to exploit the fact that the difference in the phase angles, obtained using a FFT, gives the angle between the read head positions. The new experimental system is now able to obtain the angular position of the read heads by using the index grating line. The third method relies on the presence of the index grating line on the encoder disc which may not be present in all systems. Eccentricity of disc centre relative to the centre of rotation affects the correct calculation of the angular position of the encoder disc. Algorithms have been developed by the Candidate in order to compensate for this type of error. Experimental results have shown that angular position error can be corrected successfully. The Candidate has developed methods for detection of small abnormalities of the encoder disc by using a multiple averaging technique. Computational algorithms have been developed to correct the encoder disc abnormalities by using individual information from each read head, promising results have been obtained from the experimental 1ME. An 1ME device can be tailored to fulfil the desired requirements of resolution, bandwidth and accuracy. A self calibration instrument can be developed by using the previously mentioned techniques in order to self calibrate and increase the accuracy and reliability of an IME's results.

published_or_final_version / Computer Science / Master / Master of Philosophy

The reserve growth potential of existing conventional oil reservoirs is huge. This research, through numerical simulation, aims to evaluate pattern size reduction as a strategy for improving waterflood recovery in undersaturated oil reservoirs. A plethora of studies have reported improvements in waterflood recovery resulting from pattern size reduction in heterogeneous reservoirs. The dependence of waterflood recovery on pattern size was attributed to factors such as areal reservoir discontinuity, preferential flooding directions, “wedge-edge” oil recovery, irregular pattern geometry, communication with water-bearing zones, vertical reservoir discontinuity, and project economics (Driscoll, 1974). Though many of these publications relied on decline curve analysis in estimating ultimate oil recovery, simulations completed in this thesis support their findings, specifically for compartmentalized reservoirs, fractured reservoirs, and layered reservoirs. Geostatistically-generated permeability fields were employed in the creation of various types of reservoir models. These models were populated with vertical production and injection wells. Sensitivity analysis was then performed on three development scenarios: 160, 40, and 10 acre five-spots. Based on assigned production and injection constraints, the quantity of oil recovered at simulation termination was used to calculate ultimate recovery efficiency. In homogeneous reservoir models, simulation results suggest that waterflood recovery was independent of pattern size. Similar results were also obtained from models with highly-variable non-zero permeabilities. On the other hand, pattern size reduction was found to enhance oil recovery from reservoir models with a high degree of permeability anisotropy. In such reservoirs, recovery was found to be highly dependent on bottom-hole injection pressures. The higher the injection pressure the larger the quantity of oil bypassed by widely spaced patterns. Likewise, high infill potential exists for reservoir models exhibiting areal discontinuity. In these types of models, the improvement in waterflood recovery resulting from pattern size reduction was directly related to the percentage of imbedded zero-permeability grid blocks. Ultimate oil recovery depended on the percolation of permeable grid blocks between production and injection wells. Increasing well density also enhanced waterflood recovery in vertically discontinuous reservoir models. In such layered reservoirs, the amount oil unswept with large patterns was considerably diminished because of the improved injection profiles associated with tighter patterns. / text