1,299 research outputs found
Software development management using metamodels and activity networks
This thesis develops the concept, management and control of metamodels for the
management of software development projects. Metamodels provide a more flexible
approach for managing and controlling the software engineering process and are based
on the integration of several software development paradigms. Generalised Activity
Networks are used to provide the more powerful planning techniques required for
managing metamodels. In this thesis, both new node logics, that clarify previous work
in this field, and Generalised Activity-on-the-Arrow and Generalised Activity-on-the-Node
representations are developed and defined. Activity-on-the-Node representations
reflect the current mood of the project management industry and allow constraints to be
applied directly to logical dependencies between activities. The Generalised Activity
Networks defined within this thesis can be used as tools to manage risks and
uncertainties in both software developments and general engineering projects. They
reflect the variation and uncertainties in projects more realistically and improve the
planning and scheduling of such projects. [Continues.
Estimation of Pulmonary Arterial Volume Changes in the Normal and Hypertensive Fawn-Hooded Rat from 3D Micro-CT data
In the study of pulmonary vascular remodeling, much can be learned from observing the morphological changes undergone in the pulmonary arteries of the rat lung when exposed to chronic hypoxia or other challenges which elicit a remodeling response. Remodeling effects include thickening of vessel walls, and loss of wall compliance. Morphometric data can be used to localize the hemodynamic and functional consequences. We developed a CT imaging method for measuring the pulmonary arterial tree over a range of pressures in rat lungs. X-ray micro-focal isotropic volumetric imaging of the arterial tree in the intact rat lung provides detailed information on the size, shape and mechanical properties of the arterial network. In this study, we investigate the changes in arterial volume with step changes in pressure for both normoxic and hypoxic Fawn-Hooded (FH) rats. We show that FH rats exposed to hypoxia tend to have reduced arterial volume changes for the same preload when compared to FH controls. A secondary objective of this work is to quantify various phenotypes to better understand the genetic contribution of vascular remodeling in the lungs. This volume estimation method shows promise in high throughput phenotyping, distinguishing differences in the pulmonary hypertensive rat model
Dietary nitrate reduces skeletal muscle oxygenation response to physical exercise : a quantitative muscle functional MRI study
© 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.Peer reviewedPublisher PD
SPECT Imaging of Pulmonary Blood Flow in a Rat
Small animal imaging is experiencing rapid development due to its importance in providing high-throughput phenotypic data for functional genomics studies. We have developed a single photon emission computed tomography (SPECT) system to image the pulmonary perfusion distribution in the rat. A standard gamma camera, equipped with a pinhole collimator, was used to acquire SPECT projection images at 40 sec/view of the rat thorax following injection of Tc99m labeled albumin that accumulated in the rat\u27s lungs. A voxel-driven, ordered-subset expectation maximization reconstruction was implemented. Following SPECT imaging, the rat was imaged using micro-CT with Feldkamp conebeam reconstruction. The two reconstructed image volumes were fused to provide a structure/function image of the rat thorax. Reconstruction accuracy and performance were evaluated using numerical simulations and actual imaging of an experimental phantom consisting of Tc99m filled chambers with known diameters and count rates. Full-width half-maximum diameter measurement errors decreased with increasing chamber diameter, ranging from \u3c 6% down to 0.1%. Errors in the ratio of count rate estimates between tubes were also diameter dependent but still relatively small. This preliminary study suggests that SPECT will be useful for imaging and quantifying the pulmonary blood flow distribution and the distribution of Tc99m labeled ligands in the lungs of small laboratory animals
Quantification of Bronchial Circulation Perfusion in Rats
The bronchial circulation is thought to be the primary blood supply for pulmonary carcinomas. Thus, we have developed a method for imaging and quantifying changes in perfusion in the rat lung due to development of the bronchial circulation. A dual-modality micro-CT/SPECT system was used to detect change in perfusion in two groups of rats: controls and those with a surgically occluded left pulmonary artery. Both groups were imaged following injections on separate days i) 2mCi of Tc99m labeled macroaggregated albumin (MAA) into the left carotid artery (IA) and ii) a similar injection into the femoral vein (IV). The IA injection resulted in Tc99m accumulation in capillaries of the systemic circulation including the bronchial circulation, whereas the IV resulted in Tc99m accumulation in the pulmonary capillaries. Ordered subset expectation maximization (OSEM) was used to reconstruct the SPECT image volumes and a Feldkamp algorithm was used to reconstruct the micro-CT image volumes. The micro-CT and SPECT volumes were registered, the SPECT image volume was segmented using the right and left lung boundaries defined from the micro-CT volume, and the ratio of IA radioactivity accumulation in the left lung to IV radioactivity accumulation in both lungs was used as a measure of left lung flow via the bronchial circulation. This ratio was ~0.02 for the untreated rats compared to the treated animals that had an increased flow ratio of ~0.21 40 days after left pulmonary artery occlusion. This increase in flow to the occluded left lung via the bronchial circulation suggests this will be a useful model for further investigating antiangiogenic treatments
Quantification of Bronchial Circulation Perfusion in Rats
The bronchial circulation is thought to be the primary blood supply for pulmonary carcinomas. Thus, we have developed a method for imaging and quantifying changes in perfusion in the rat lung due to development of the bronchial circulation. A dual-modality micro-CT/SPECT system was used to detect change in perfusion in two groups of rats: controls and those with a surgically occluded left pulmonary artery. Both groups were imaged following injections on separate days i) 2mCi of Tc99m labeled macroaggregated albumin (MAA) into the left carotid artery (IA) and ii) a similar injection into the femoral vein (IV). The IA injection resulted in Tc99m accumulation in capillaries of the systemic circulation including the bronchial circulation, whereas the IV resulted in Tc99m accumulation in the pulmonary capillaries. Ordered subset expectation maximization (OSEM) was used to reconstruct the SPECT image volumes and a Feldkamp algorithm was used to reconstruct the micro-CT image volumes. The micro-CT and SPECT volumes were registered, the SPECT image volume was segmented using the right and left lung boundaries defined from the micro-CT volume, and the ratio of IA radioactivity accumulation in the left lung to IV radioactivity accumulation in both lungs was used as a measure of left lung flow via the bronchial circulation. This ratio was ~0.02 for the untreated rats compared to the treated animals that had an increased flow ratio of ~0.21 40 days after left pulmonary artery occlusion. This increase in flow to the occluded left lung via the bronchial circulation suggests this will be a useful model for further investigating antiangiogenic treatments
Mimicking human strategies in fighting games using a data driven finite state machine
Multiplayer fighting videogames have become an
increasingly popular over the last few years, especially with the
introduction of online play, making for a more competitive
experience. Multiplayer fighting games give players the
opportunity to utilize particular strategies and tactics to win,
allowing them to use their own signature style. As a player can
only play against a particular opponent who is actively
participating in the game themselves, they cannot practice
combating the opponent’s style if the opponent is not
participating in the game. This paper presents a novel approach
for an avatar to learn and mimic the style of a player. It does this
by recording and analyzing the data before splitting it up into
two tiers; tactical data and strategic data.. The approach uses a
Naïve Bayes classifier to classify the tactics to particular states,
and a Data Driven Finite State Machine to dictate when certain
tactics are used. Statistics recorded during an experiment
involving the approach are discussed, which indicate that the
architecture of the Artificial Intelligence is fit for purpose, but
does require refinement. Limitations of the architecture are
discussed, including that such an approach may not provide
accurate results when more parameters are considered
The effect of a computer-based cartooning tool on children’s cartoons and written stories
This paper reports a study assessing a new computer tool for cartoon storytelling,
created by the authors for a target audience in the upper half of the
English and Welsh Key Stage 2 (Years 5 and 6, covering ages 9 to 11 years).
The tool attempts to provide users with more opportunities for expressive visualisation
than previous educational software; its design was motivated by earlier
work connecting “moving image literacy” with print literacy, and it was used
here in storywriting preparation work: users first visualised a known story, then
wrote their versions of it based on the cartoons they had made. The stories produced
are compared with stories written using two other preparation activities,
one a pencil-and-paper cartooning exercise and the other a teacher’s normal
planning session, which also resulted in a retelling of a known story.
The study finds that no one preparation process had a noticeably different
effect on the final written stories; however, the cartoons produced with the
software are found to be quite different to their paper counterparts, showing a
greater variety of character action, pose and interaction, slightly more variety
of camera shot distance, and more pictures. Children’s and teachers’ reactions
to the software tool are also discussed
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