<div>Volumetric cloud generation and rendering algorithms are well-developed to meet the need for a realistic sky performance in animation or games. However, it is challenging to create a stylized or designed animation for volumetric clouds using physics-based generation and simulation methods in real-time.</div><div>The problem raised by the research is the current volumetric cloud animation controlling methods are not art-directable. Making a piece of volumetric cloud move in a specific way can be difficult when using only a physics-based simulation method. The purpose of the study is to implement an animating method for volumetric clouds and with art-directable controllers. Using this method, a designer can easily control the cloud's motion in a reliable way. The program will achieve interactive performance using parallel processing with CUDA. Users will be able to animate the cloud by input a few vectors inside the cloud volume. </div><div>After reviewing the literature related to the real-time simulation method of clouds, texture advection algorithms, fluid simulation, and other processes to achieve the results, the thesis offers a feasible design of the algorithm and experiments to test the hypotheses. The study uses noise textures and fractional Brownian motion (fBm) to generate volumetric clouds and render the clouds by the ray marching technique. The program will render user input vectors and a three-dimension interpolation vector field with OpenGL. By adding or changing input vectors, the user will gain a divergence minimization interpolation field. The cloud volume could be animated by the texture advection technique based on the interpolation vector field in real-time. By inputting several vectors, the user could plausibly animate the volume cloud in an art-directable way.</div>

Ce travail si concerne l`etude d`evolution du volume du fois apres l`hepatectomie majeure chez les porcs.Le planning se compose des imagairies sequentielle avant et apres le chirurgie, dans laquelle ablation d`une parite precis du fois est effectue. En suite, on etudie l`evolution de volume du fois et les facteures hemodynamic qui ont d`influence sur cet evolution. / The aim of this project is double. Firstly, relationships between liver function, blood flows and architecture along with liver volume after major hepatectomy will be carefully analyzed by combining experiments and modeling on multiple levels and scales. These results will be used by mathematicians to develop an alternative evaluation procedure based on innovative tools in order to improve identification of possible or likely post-operative liver failure as early as possible. In this way a critical liver function decrease can be duly treated. Preliminary studies in pigs indicate that patients in which liver failure is likely to occur, may significantly benefit from an implantable surgical device capable of modulating the diameter of the portal vein hence controlling the portal venous pressure into the liver.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20241号 / 医博第4200号 / 新制||医||1020(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 今中 雄一, 教授 川上 浩司, 教授 川村 孝 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24797号 / 医博第4989号 / 新制||医||1066(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 花川 隆, 教授 髙橋 良輔, 教授 高橋 淳 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Introduction- Exercise-induced plasma volume (PV) expansion is typically associated with an increase in plasma albumin content. Increased hepatic albumin synthesis, a transcriptionally regulated process, is thought to contribute to the increase in albumin content. Objective- We tested the hypothesis that exercise training induces an increase in albumin gene expression in relationship to the increase in PV. Methods and Results- 40 adult male Sprague-Dawley rats weighing between 245-350 grams were randomly assigned to one of four groups: cage control (CC); sham exercise 10 min/day at 48% VO2max (NE); continuous exercise training, 60 min /day at 72% VO2max (LI); and high intensity, intermittent exercise training, 8 bouts of 4 min at 98% VO2max followed by 5 min at 48% VO2max (HI). The training period lasted for two weeks with 12 training sessions with equalized training volumes in the exercise groups. 24 hours after the last training session the rats were anesthetized and a jugular catheter was placed for collecting blood samples during PV determination by a dilution of a labeled-albumin molecule (Texas Red albumin). The liver and red quadriceps (RQ) muscle tissue was then removed, flash frozen, and stored for later analysis. The training protocol produced a significant increase in RQ citrate synthase activity (p < 0.05). PV increased in proportion to the exercise intensity (p < 0.05) averaging 23.6 ± 2.7 ml•kg-1 body weight in the CC group and 26.6 ± 1.3 ml•kg-1 body weight in the HI group. Albumin mRNA expression determined by real time polymerase chain reaction (PCR) increased 2.2 ± 0.1 and 2.9 ± 0.2 fold following LI and HI exercise training, respectively. Conclusion- These data support the hypothesis that, during exercise-induced PV expansion, albumin gene expression is increased and contributes to an increase in plasma albumin content and PV.

The thesis examines the impact of perceived brightness and contrast balance in relation to the spatial volume; physical volume transforming into a perceived volume in light. Two static viewpoints of 20th century’s museum architecture have been tested to observe qualitative features in daylight entering through architecturally devised openings. Anders Liljefors’s “7 parameters of light” based on visual-physical theory and James Gibson’s perception factors relating to our visual field help evaluate the perceived qualities. The thesis directs towards understanding relationship of brightness and contrast perception with the perceived color of space and spaciousness of the architectural volumes. Individual experiment with physical mock-up replicating the spatial volumes in contextual sun altitudes as well as visual representation of analyzing perceptual parameters have been documented and discussed. Also, methodology includes a collective evaluation surveying observers’ perception of “lighting features” and “spatial features” seeing the fish-eye images of the viewpoints as if looking into the physical mock-up. The comparative analysis in this research is an attempt to contemplate qualitative observation tool as an objective reference in relation to the subjective experience for architectural lighting design process. The investigation follows case studies of two exhibition spaces designed by architects - Carlo Scarpa and Louis Kahn addressing both diffuse skylight and direct sunlight entering through architecturally devised openings.

This dissertation includes a collection of studies that aim to improve the way we represent and visualize volume data. The advancement of medical imaging has revolutionized healthcare, providing crucial anatomical insights for accurate diagnosis and treatment planning. Our first study introduces an innovative technique to enhance the utility of medical images, transitioning from monochromatic scans to vivid 3D representations. It presents a framework for reference-based automatic color transfer, establishing deep semantic correspondences between a colored reference image and grayscale medical scans. This methodology extends to volumetric rendering, eliminating the need for manual intervention in parameter tuning. Next, it delves into deep learning-based super-resolution for volume data. By leveraging color information and supplementary features, the proposed system efficiently upscales low-resolution renderings to achieve higher fidelity results. Temporal reprojection further strengthens stability in volumetric rendering. The third contribution centers on the compression and representation of volumetric data, leveraging coordinate-based networks and multi-resolution hash encoding. This approach demonstrates superior compression quality and training efficiency compared to other state-of-the-art neural volume representation techniques. Furthermore, we introduce a meta-learning technique for weight initialization to expedite convergence during training. These findings collectively underscore the potential for transformative advancements in large-scale data visualization and related applications.

<p>In today’s fast-paced data-driven world, accumulating and organizing streams of high-resolution information plays a vital role in numerous decision and design tasks. The transportation sector is a prime example of this. Fine-scale information on traffic exposure at specific observation periods is critical to the successful analysis of road safety. Annual Average Daily Traffic (AADT) and hourly traffic volumes represent essential statistics to predict crash risk under time-dependent conditions, such as, weather and seasonal traffic variations. State highway agencies including the Indiana Department of Transportation (INDOT) collect traffic count data using multiple permanent and coverage count stations. However, approximately ten percent of the local-administered road segments in Indiana are included in their database. To impute the missing data, predictive models that can accurately forecast AADT and consequently, hourly traffic volumes, will be of great value.</p> <p><br></p> <p>To address this problem, this thesis proposes a methodology to predict traffic volumes in different classes of urban road segments in Indiana. Two sets of regression models have been developed: (1) AADT Estimation Model, and (2) Hourly Traffic Volume Model. These models include effects of spatial and temporal variations, land use, roadway characteristics and, previously-overlooked in such models, road network connectivity and route selection. These, in turn, address two important research questions: (1) how trips are generated and (2) how people choose routes. The spatial and temporal effects that were considered in the analysis are travel propensity, travel time excess index, road class, hour of day, day of week and seasonal variations. While travel propensity captures particulars of network connectivity and land-use characteristics in traffic analysis zones (TAZ), the travel time excess index accounts for commuters’ route-choice. The estimation results indicate that all these variables are strongly correlated with traffic volumes on considered roadways. Reasonable estimations of hourly traffic volumes on a network scale can be achieved using the proposed model. In addition to aiding safety management at disaggregate level, hourly traffic predictions can help highway agencies in other system-wide analysis where such traffic information is needed.</p>

In this thesis, we included results from two studies. The first one considered the effects of the blood volume changes, during blood donation, on the heart rate variability (HRV) measured, non-invasively, form electrocardiographic (ECG) and photoplethysmographic (PPG) signals. Our results showed that, during blood donation, there were no significant changes in the pulsatile area of PPG signal, while heart rate increased. No significant changes were noticed in HRV extracted from both signals. Error analysis between the HRV extracted from ECG and peak interval variability (PIV) suggested that the error during blood donation was increased which means that the use of PIV extracted from PPG signal, used as a replacement diagnostic tool in clinical applications, needs further investigations and should be carefully studied in non-stationary cardiovascular situations such as blood donation. The imbalance between the two branches of the autonomic nervous system, sympathetic and parasympathetic, vagal, may result in a harmful activation of myocardial tissues which cause arrhythmias and sudden cardiac death. Although the study of the sympathovagal balance have been attracting many researchers, further studies are needed to elucidate the effects of many kinds of drugs on the autonomic modulation of the cardiac muscle, specifically, the cells of sinoatrial (SA) node. The aim of the second part of this thesis was to assess the effects of calcium channel blocker (Verapamil), calcium channel sensitizer (Levosimendan), calcium chloride (CaCl2), the combinations of verapamil/ CaCl2, levosimendan/ CaCl2, and noradrenaline infusion on beat-to-beat cardiovascular variability represented, in this research, by systolic blood pressure variability (SBPV), and stroke volume variability (SVV) signals. We used Fat Fourier Transform (FFT) to evaluate the power spectral density of the fluctuations in both signals to evaluate the effects of short-term treatments with those drugs on the sympathovagal balance in normal rats. Then, we compared the spectra obtained from SBPV and SVV to decide which of these fluctuations along with corresponding spectrum was more able to provide a clear feedback about the autonomic nervous system. Our data suggests that there were a significant correlations between low- (LF), mid- (MF), and high-frequency (HF) spectra obtained from SBPV and SVV except between the HF spectra estimated from after the infusion of levosimendan where a poor correlation (r = 0.530, p = 0.281) was noticed. This that both HF components obtained provide different information regarding the autonomic nervous system modulation of the SA node cells, while the results obtained from the rest of experiments showed that both signals provide same information about the modulation of sympathetic and parasympathetic tone due to all stages of different drugs infusion studied in this thesis. Besides that, we found that both spectra may be used to track the fluctuations in the cardiac output as a result of the drugs infusion.

To aid diagnosis, treatment planning, and patient education, clinicians require tools to anal- yse and explore the increasingly large three-dimensional (3-D) datasets generated by modern medical scanners. Direct volume rendering is one such tool finding favour with radiologists and surgeons for its photorealistic representation. More recently, volume illustration — or non-photorealistic rendering (NPR) — has begun to move beyond the mere depiction of data, borrowing concepts from illustrators to visually enhance desired information and suppress un- wanted clutter. Direct volume rendering generates images by accumulating pixel values along rays cast into a 3-D image. Transfer functions allow users to interactively assign material properties such as colour and opacity (a process known as classification). To achieve real-time framerates, the rendering must be accelerated using a technique such as 3-D texture mapping on commod- ity graphics processing units (GPUs). Unfortunately, current methods do not allow users to intuitively enhance regions of interest or suppress occluding structures. Furthermore, addi- tional scalar images describing clinically relevant measures have not been integrated into the direct rendering method. These tasks are essential for the effective exploration, analysis, and presentation of 3-D images. This body of work seeks to address the aforementioned limitations. First, to facilitate the research program, a flexible architecture for prototyping volume illustration methods is pro- posed. This program unifies a number of existing techniques into a single framework based on 3-D texture mapping, while also providing for the rapid experimentation of novel methods. Next, the prototyping environment is employed to improve an existing method—called tagged volume rendering — which restricts transfer functions to given spatial regions using a number of binary segmentations (tags). An efficient method for implementing binary tagged volume rendering is presented, along with various technical considerations for improving the classifi- cation. Finally, the concept of greyscale tags is proposed, leading to a number of novel volume visualisation techniques including position modulated classification and dynamic exploration. The novel methods proposed in this work are generic and can be employed to solve a wide range of problems. However, to demonstrate their usefulness, they are applied to a specific case study. Ischaemic heart disease, caused by narrowed coronary arteries, is a leading healthconcern in many countries including Australia. Computed tomography angiography (CTA) is an imaging modality which has the potential to allow clinicians to visualise diseased coronary arteries in their natural 3-D environment. To apply tagged volume rendering for this case study, an active contour method and minimal path extraction technique are proposed to segment the heart and arteries respectively. The resultant images provide new insight and possibilities for diagnosing and treating ischaemic heart disease.