In this study, the associated dynamic of water droplets at low impact velocity on the Superhydrophobic surface have been investigated. The experiment is conducted on superhydrophobic surface (SH), (Contact Angel > 1500) while varying the impact velocity (V0). When the drop hits the surface, large oscillation starts, and the capillary waves travel up to the upper of the drop where a cylindrical cavity can be formed inside the drop. The cavity closes up in a self-similar way until collapse, followed by a violent singular jet which can reach up to 35 m/s. The study showed that during drop receding, the cavity can collapse in different scenarios based on the impact velocity and the surface wettability. More importantly, the collapse is observed for the first time at very high-speed video, up to 5 million fps. Furthermore, we correct the optical distortion of the cavity due to the curvature of the drop surface. This study classifies all of the 5 encountered behaviors of the cavity collapse. The jet formation and speed are strongly dependent on the specific cavity configuration. Very fast jetting behavior is observed when the collapse is pinch-off singularity which reaches zero value in the middle of the drop. Other behaviors of the collapse such the unsymmetrical closing of the cavity or bubble entrapment is discussed. The optical distortion factor is calculated through 3 different approaches. The first one is an experimental calibration technique where a small cylinder is inserted into the drop. While the other two approaches are indirect implantations of theoretical models presented in the literature to fit the instantaneous geometrical shape of the cavity inside the drop. The distortion factor (DF) gives in all cases a similar value. Therefore, the averaged distortion value is calculated, and it is a magnification of 33% increase of the actual size. The experiment results of the cavity radius are compared with power-laws and the modified Rayleigh-Plesset equation for free cylindrical flow and good agreement is shown.

This thesis presents the rate distortion analysis of conditional motion estimation, a process in which motion computation is restricted to only active pixels in the video. We model active pixels as independent and identically distributed Gaussian process and inactive pixels as Gaussian-Markov process and derive the rate distortion function based on conditional motion estimation. Rate-Distortion curves for the conditional motion estimation scheme are also presented. In addition this thesis also presents the hardware implementation of a block based motion estimation algorithm. Block matching algorithms are difficult to implement on FPGA chip due to its complexity. We implement 2D-Logarithmic search algorithm to estimate the motion vectors for the image. The matching criterion used in the algorithm is Sum of Absolute Differences (SAD). VHDL code for the motion estimation algorithm is verified using ISim and is implemented using Xilinx ISE Design tool. Synthesis results for the algorithm are also presented.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第12889号 / 論医博第2089号 / 新制||医||1007(附属図書館) / 31643 / (主査)教授 福山 秀直, 教授 千葉 勉, 教授 平岡 眞寛 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

We consider the asymptotic minimum rate under the logarithmic loss distortion constraint. More specifically, we find the asymptotic minimum rate expression when given distortions get close to 0. The problem under consideration is separate encoding and joint decoding of correlated two information sources, subject to a logarithmic loss distortion constraint. We introduce a test channel, whose transition probability (conditional probability mass function) captures the encoding and decoding process. Firstly, we find the expression for the special case of doubly symmetric binary sources with binary-output test channels. Then the result is extended to the case where the test channels are arbitrary. When given distortions get close to 0, the asymptotic rate coincides with that for the aforementioned special case. Finally, we consider the general case and show that the key findings for the special case continue to hold. / Thesis / Master of Applied Science (MASc)

Inlet distortion is an important consideration in fan performance. Distortion can be generated through flight conditions and airframe-engine interfaces. The focus of this paper is a series of high-fidelity, time-accurate Computational Fluid Dynamics (CFD) simulations of a multistage fan, investigating distortion transfer, distortion generation, and the underlying flow physics under different operating conditions. The simulations are full annulus and include 3 stages and the inlet guide vane (IGV). The code used to carry out these simulations is a modified version of Overflow2.2 that was developed as part of the Computational Research and Engineering Acquisition Tools and Environment (CREATE) program. The inlet boundary condition is a single revolution (sinusoidal pattern with one period over the circumference ) total pressure distortion. Simulations at choke, design, and near stall are analyzed and compared to experimental data. Distortion transfer and generation is analyzed under these different operating conditions. Analysis includes the phase and amplitude of total temperature and pressure distortion through each stage of the fan, level of distortion transfer and generation in each stage, and blade loading. An understanding of the flow physics associated with distorted flows will help fan designers account for unsteady flow physics at design and off-design operating conditions, in order to build more robust fans offering a greater stability margin.

Inlet distortion is an important consideration in fan performance. Distortion can be caused through flight conditions and airframe-engine interfaces. The focus of this paper is a series of high-fidelity time accurate Computational Fluid Dynamics (CFD) simulations of a multistage fan. These investigate distortion transfer and generation as well as the underlying flow physics of these phenomena under different operating conditions. The simulations are performed on the full annulus of a 3 stage fan. The code used to carry out these simulations is a modified version of OVERFLOW 2.2 developed as part of the Computational Research and Engineering Acquisition Tools and Environment (CREATE) program. Several modifications made to the code are described within this thesis. The inlet boundary condition is specified as a 1/rev total pressure distortion. Simulations at choke, design, and near stall points are analyzed and compared to experimental data. Analysis includes the phase and amplitude of total temperature and pressure distortion through each stage of the fan and blade loading plots. An understanding of the flow physics associated with distorted flows will help designers account for unsteady flow physics at design and off-design operating conditions and build more robust fans with a greater stability margin.

This study investigated the frequency of distortion that occurs when raw score patterns of Affinity 2.0, a viewing time measure designed to assess sexual interest, are converted to ipsative scores. Eighty-eight percent of a sample of ninety-nine non-pedophilic, exclusively heterosexual males' profiles sustained some degree of distortion. The study also applied Brown's (2005) approach to predicting distortion with this sample of males' responses. Brown's techniques were largely ineffective in predicting males' distortion scores.

Deep generative models when utilized in lossy image compression tasks can reconstruct realistic looking outputs even at extremely low bit-rates, while traditional compression methods often exhibit noticeable artifacts under similar conditions. As a result, there has been a substantial surge of interest in both the information theoretic aspects and the practical architectures of deep learning based image compression. This thesis makes contributions to the emerging framework of rate-distortion-perception theory. The main results are summarized as follows: 1. We investigate the tradeoff among rate, distortion, and perception for binary sources. The distortion considered here is the Hamming distortion and the perception quality is measured by the total variation distance. We first derive a closed-form expression for the rate-distortion-perception tradeoff in the one-shot setting. This is followed by a complete characterization of the achievable distortion-perception region for a general representation. We then consider the universal setting in which the encoder is one-size-fits-all, and derive upper and lower bounds on the minimum rate penalty. Finally, we study successive refinement for both point-wise and set-wise versions of perception-constrained lossy compression. A necessary and sufficient condition for point-wise successive refinement and a sufficient condition for the successive refinability of universal representations are provided. 2. Next, we characterize the expression for the rate-distortion-perception function of vector Gaussian sources, which extends the result in the scalar counterpart, and show that in the high-perceptual-quality regime, each component of the reconstruction (including high-frequency components) is strictly correlated with that of the source, which is in contrast to the traditional water-filling solution. This result is obtained by optimizing over all possible encoder-decoder pairs subject to the distortion and perception constraints. We then consider the notion of universal representation where the encoder is fixed and the decoder is adapted to achieve different distortion-perception pairs. We characterize the achievable distortion-perception region for a fixed representation and demonstrate that the corresponding distortion-perception tradeoff is approximately optimal. Our findings significantly enrich the nascent rate-distortion-perception theory, establishing a solid foundation for the field of learned image compression. / None / Doctor of Philosophy (PhD)

Modem high-performance military aircraft are subjected to rapid flight maneuvers which place great operational demands on their compression system by producing highly distorted flow to the compressor. Inlet distortion generally reduces the engine compressor stability margin and may induce compressor surge at high rotational speeds, or rotating stall at lower rotational speeds. Therefore, a computational fluid dynamics (CFD) based compressor simulation would be very useful in the design, test, and analysis process since it gives additional information with inexpensive modifications. A new CFD simulation called the Turbine Engine Analysis Compressor Code (TEACC) was designed to meet these requirements. This code solves the compressible 3D Euler equations modified to include turbomachinery source terms which simulates the effect of the compressor blades. The source terms are calculated for each blade row by the application of a streamline curvature code. A methodology was developed for calculating turbomachinery source terms and distributing them axially, radially, and circumferentially while maintaining a sensitivity to strong inlet distortion. TEACC was compared with experimental data from NASA Rotor 1 B, a transonic rotor. Experimental data from Rotor 1 B were available for comparison with TEACC results for a clean inlet and for an inlet distortion produced by a 90-degree, one-per-revolution screen. TEACC results compared very well with experimental data with a clean inlet. Comparison with experimental data with inlet distortion demonstrated TEACC's ability to characterize the compressor overall, and to accurately predict the magnitude and shape of exit total temperature and exit total pressure in the distorted region. TEACC calculated the overall character of exit total pressure and exit total temperature in the nondistorted region, identifying the location of the largest value just after the inlet distortion and the decrease in exit total values through the nondistorted region in the direction of rotation. / Ph. D.