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Inverse Source Locating Method Based on graphical analysis of Dye Plume Images in a Turbulent Flow

Open Journal of Fluid Dynamics 2016年第4期6卷 343-360页

作者： Qianqian Shao Daichi Sekine Takahiro Tsukahara Yasuo Kawaguchi Department of Mechanical Engineering Tokyo University of Science Chiba Japan

The inverse estimation of a source location of pollutant released into a turbulent flow is a probability problem instead of a deterministic one, as the turbulent flow is chaotic and irreversible. However, researches can be conducted to provide helpful instructions to the possible source location with corresponding uncertainty. This study aims to propose a method of inverse estimation of a passive-scalar source location. Experimental investigation of the dye plume characteristics released into a fully-developed turbulent flow is performed in a water channel. A planar laser-induced fluorescence (PLIF) technique is used to obtain two-dimensional images of spreading dye plumes at a bulk Reynolds number of 20,000. The distributions of high concentration areas in the PLIF images are chosen as features that characterize the traveling (diffusion) distance or time from the dye source. graphical analysis is used to extract these high concentration areas. The procedure of graphical analysis has three steps: 1) binarization using a threshold to extract high concentration dye patches;2) labeling individual high-concentration dye patches in the binarized images;and 3) pixel-counting to measure the area and perimeter of each dye patch. We examine the variations of fractal dimension of patches, and the fractal dimension is observed to be almost constant irrespective of the distance from the source. The kurtosis of the probability density function curve of the logarithm dimensionless dye patch areas is found to be related with the downstream diffusion distance, based on which an inverse estimation method to locate a passive-scalar point source is proposed and evaluated.

关键词： graphical analysis Inverse Problem Passive Scalar Diffusion Source Estimation Turbulent Flow

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Effect of the Cutter Parameters and Machining Parameters on the Interference in Gear Slicing

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1118-1126页

作者： CHEN Xinchun LI Jia LOU Benchao SHI Jiang YANG Qijun Key Laboratory of Mechanism and Equipment Design of Ministry of Education Tianjin University

Current researches have not yet found the effect law of the cutter parameters and machining parameters on the interference in gear slicing, the interference between the cutter and machined gear often happens because the appropriate cutter parameters and machining parameters cannot be set, which reduces the gear machining accuracy. The relative position between the major flank face and edge-sweeping surface, distribution law of the interference area in forming process of edge-sweeping surface, and effect law of relative positions among edge-sweeping surfaces on the interference are studied by graphical analysis. The effect law of the cutter parameters and machining parameters on the interference is found. The effect law shows that the interference in gear slicing can be controlled when the relief angle measured on the top edge and feed of every rotation are chosen respectively larger than 9~ and smaller than 0.15 mrn/r. An internal helical gear is sliced with the spur slice cutter and the cutter parameters and machining parameters are set based on above the effect law. The machined gear is measured in Gear Measuring Center and the detection result shows that the comprehensive accuracy reaches GB/T Class 7, where some reach GB/T Class 6. The result can meet the gear machining accuracy requirement and shows that the effect law found is valid. The problem of the interference in gear slicing is solved and the gear machining accuracy can be improved.

关键词： gear slicing interference edge-sweeping surface graphical analysis

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Recent advances in parametric neuroreceptor mapping with dynamic PET:basic concepts and graphical analyses

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Neuroscience Bulletin 2014年第5期30卷 733-754页

作者： Seongho Seo Su Jin Kim Dong Soo Lee Jae Sung Lee Department of Nuclear Medicine College of Medicine Department of Brain and Cognitive Sciences College of Natural Sciences institute of Radiation Medicine Medical Research Center Institute of Radiation Medicine Medical Research Center Department of Molecular Medicine and Biopharmaceutical Sciences Graduate School of Convergence Science and Technology Department of Biomedical Sciences College of Medicine Seoul National University

Tracer kinetic modeling in dynamic positron emission tomography （PET） has been widely used to investigate the characteristic distribution patterns or dysfunctions of neuroreceptors in brain diseases. Its practical goal has progressed from regional data quantification to parametric mapping that produces images of kinetic-model parameters by fully exploiting the spatiotemporal information in dynamic PET data. graphical analysis （GA） is a major parametric mapping technique that is independent on any compartmental model configuration, robust to noise, and computationally efficient. In this paper, we provide an overview of recent advances in the parametric mapping of neuroreceptor binding based on GA methods. The associated basic concepts in tracer kinetic modeling are presented, including commonly-used compartment models and major parameters of interest. Technical details of GA approaches for reversible and irreversible radioligands are described, considering both plasma input and reference tissue input models. Their statistical properties are discussed in view of parametric imaging.

关键词： dynamic positron emission tomography graphical analysis neuroreceptor imaging parametric image tracer kinetic modeling

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