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Multi-Scale Dilated Convolution Network for SPECT-MPI Cardiovascular Disease Classification with Adaptive Denoising and Attenuation Correction

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Computer Modeling in engineering & Sciences 2025年第1期142卷 299-327页

作者： A.Robert Singh Suganya Athisayamani Gyanendra Prasad Joshi Bhanu Shrestha department of Computational Intelligence SRM Institute of Science and TechnologyKattankulathur603203Tamil NaduIndia school of Computing Sastra Deemed to be UniversityThanjavur613401Tamil NaduIndia department of Artificial Intelligence&Software Kangwon National UniversitySamcheok25913Republic of Korea department of Information Convergence System Graduate School of Smart ConvergenceKwangwoon UniversitySeoul01897Republic of Korea

Myocardial perfusion imaging(MPI),which uses single-photon emission computed tomography(SPECT),is a well-known estimating tool for medical diagnosis,employing the classification of images to show situations in coronary artery disease(CAD).The automatic classification of SPECT images for different techniques has achieved near-optimal accuracy when using convolutional neural networks(CNNs).This paper uses a SPECT classification framework with three steps:1)Image denoising,2)Attenuation correction,and 3)Image *** denoising is done by a U-Net architecture that ensures effective image *** correction is implemented by a convolution neural network model that can remove the attenuation that affects the feature extraction process of ***,a novel multi-scale diluted convolution(MSDC)network is *** merges the features extracted in different scales and makes the model learn the features more *** scales of filters with size 3×3 are used to extract *** three steps are compared with state-of-the-art *** proposed denoising architecture ensures a high-quality image with the highest peak signal-to-noise ratio(PSNR)value of *** proposed classification method is compared with the five different CNN models,and the proposed method ensures better classification with an accuracy of 96%,precision of 87%,sensitivity of 87%,specificity of 89%,and F1-score of 87%.To demonstrate the importance of preprocessing,the classification model was analyzed without denoising and attenuation correction.

关键词： SPECT-MPI CAD MSDC denoising attenuation correction classification

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Design Method of Guide Vane for Wells Turbine

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Journal of Thermal Science 2006年第2期15卷 126-131页

作者： Masami SUZUKI department of mechanical engineering graduate school of engineering The University of Tokyo

Guide vanes are installed in the Wells turbine in order to improve its efficiency, self-rotating characteristics and off design performance with stall. This work attempts to explain the role of these guide vanes on the basis of momentum theory. It is shown that the upstream vanes are more effective in enhancing efficiency than the downstream ones. A design method for guide vanes is suggested based on experimental data and potential theory. Experimental studies carried out by the author confirm the theory proposed.

关键词： wells turbine guide vane cascade potential flow wave energy converter ocean engineering

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mechanical behavior and properties of fiber reinforced ceramic matrix composites for high temperature use

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航空动力学报 2007年第4期22卷 594-601页

作者： Chongdu Cho Qiang Pan Sangkyo Lee department of mechanical engineering Inha University mechanical engineering graduate school Inha University

Ceramics can keep their mechanical characteristics up to 2 000℃ or *** this paper,A model to predict ultimate strength of continuous fiber-reinforced brittle matrix composites is developed.A statistical theory for the strength of a uni-axially fiber-reinforced brittle matrix composite is *** a semi-empirical frictional heating method for estimating in-situ interfacial shear in fiber-reinforced ceramic matrix composites was *** uneven fiber packing variation as well as uneven micro-damage during fatigue can be expected to have effects on the composites:generation of frictional heating,thermal gradients,and residual stresses around local fiber *** study examined those engineering interests by the finite element method.

关键词：高温纤维增强型陶瓷基复合材料机械性能有限元航空推进系统

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Flow imbalance in MHD flows in splitting ducts with locally different electric conductivities of the walls

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Journal of Hydrodynamics 2018年第5期30卷 920-927页

作者： Yang Luo Mengqi Zhu C.N.Kim department of mechanical engineering Graduate School Kyung Hee University department of mechanical engineering College of Engineering Kyung Hee University

In this study, three-dimensional liquid-metal magnetohydrodynamic splitting flows in a duct with one inflow channel and two outflow channels with locally different wall electric conductivities（different conductance ratios） are computationally examined. The numerical calculation is achieved with the use of CFX code, with a structured grid system chosen after a series of mesh independence tests. The detailed features of the MHD flows are depicted in a case where the electric conductivities of the two outflow ducts are quite different. Also, the interdependency among the current, fluid velocity, pressure and electric potential is elucidated in order to describe the electromagnetic characteristics of the liquid-metal flows. The result shows that the imbalance of the mass flow rate in the two outflow channels strongly depends on the wall conductivity（i.e., conductance ratio） of each outflow channel.

关键词： Liquid metal flow splitting duct flow imbalance numerical examination conductance ratio

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Mixing features in an electromagnetic rectangular micromixer for electrolyte solutions

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Journal of Hydrodynamics 2017年第4期29卷 668-678页

作者： M.M.Wen C.N.Kim department of mechanical engineering Graduate School Kyung Hee University department of mechanical engineering College of Engineering Kyung Hee University

In this study, a new magnetohydrodynamic（MHD） mixer for electrolyte solutions with pumping function is reported, and the mixing performance of the device for two different electrolyte solutions is numerically examined in a uniform magnetic field. Application of different potentials to different electrodes allows the current to be induced. The combination of the induced current and magnetic field yields Lorentz force, resulting in the fluid motion. The numerical simulation for the flows in the device is carried out with commercial software CFX. The validity of CFX code for the present numerical model is presented. The mixing performance of the fluids is investigated in many different cases with different combinations of input voltage of the electrode. This study shows that the mixing performance can be enhanced by applying spatially alternating positive and negative voltages to the electrodes. The present simulation results show that with a magnetic field intensity lower than 0.5 T, a voltage difference smaller than 2.0 V, and an electric conductivity of electrolyte solution of 1.5 S/m the pumping capabilities ranging 1.6×10^（-7）-3.6×10^（-6） kg/s and the mixing indexes higher than 0.90 can be obtained with sophisticated designs of the micromixer.

关键词： Mixer electrolyte solution Lorentz force CFX

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Mixing of two different electrolyte solutions in electromagnetic rectangular mixers

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Journal of Hydrodynamics 2016年第1期28卷 114-124页

作者： Meimei WEN Chang Nyung KIM Yue YAN department of mechanical engineering Graduate School Kyung Hee University department of mechanical engineering College of Engineering Kyung Hee University

This study proposes a new electromagnetic rectangular mixer, and numerically examines the mixing characteristics of two different electrolyte solutions in the device under a uniform magnetic field. The mixer consists of a conduit with electrodes equipped on its top and bottom walls. The difference in the electric potentials applied to the sets of electrodes induces the current. The combination of the induced current and magnetic field yields Lorentz force, resulting in the fluid motion for pumping and mixing of the two different fluids. The numerical simulation is carried out with the use of commercial software CFX. The present numerical model is validated by an existing numerical work. The effect of different variables on mixing efficiency is investigated in many different cases with two different heights of the duct and various input voltages of the electrodes. The current simulation results indicate that the mixing performance can be enhanced by using multiple sets of electrodes and applying higher input voltages（absolute values） to the electrodes.

关键词： CFX electrolyte solution Lorentz force mixer mixing efficiency

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Analysis of Machinable Structures and Their Wettability of Rotary Ultrasonic Texturing Method

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Chinese Journal of mechanical engineering 2016年第6期29卷 1187-1192页

作者： XU Shaolin SHIMADA Keita MIZUTANI Masayoshi KURIYAGAWA Tsunemoto Division of Biomechanical engineering Graduate School of Biomedical Engineering Tohoku University department of mechanical Systems engineering Graduate School of Engineering Tohoku University

Tailored surface textures at the micro- or nanoscale dimensions are widely used to get required functional performances. Rotary ultrasonic texturing （RUT） technique has been proved to be capable of fabricating periodic micro- and nanostructures. In the present study, diamond tools with geometrically defined cutting edges were designed for fabricating different types of tailored surface textures using the RUT method. Surface generation mechanisms and machinable structures of the RUT process are analyzed and simulated with a 3D-CAD program. Textured surfaces generated by using a triangular pyramid cutting tip are constructed. Different textural patterns from several micrometers to several tens of micrometers with few burrs were successfully fabricated, which proved that tools with a proper two-rake-face design are capable of removing cutting chips efficiently along a sinusoidal cutting locus in the RUT process. Technical applications of the textured surfaces are also discussed. Wetting properties of textured aluminum surfaces were evaluated by combining the test of surface roughness features. The results show that the real surface area of the textured aluminum surfaces almost doubled by comparing with that of a flat surface, and anisotropic wetting properties were obtained due to the obvious directional textural features.

关键词： rotary ultrasonic texturing geometrically defined cutting edges surface generation mechanisms machinable structures,wetting properties

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Study on the Rotor Design Method for a Small Propeller-Type Wind Turbine

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Journal of Thermal Science 2016年第4期25卷 355-362页

作者： Yasuyuki Nishi Yusuke Yamashita Terumi Inagaki department of mechanical engineering Ibaraki University graduate school of Science and engineering Ibaraki University

Small propeller-type wind turbines have a low Reynolds number,limiting the number of usable airfoil ***,their design method is not sufBciently established,and their performance is often *** ultimate goal of this research is to establish high-performance design guidelines and design methods for small propeller-type wind *** that end,we designed two rotors:Rotor A,based on the rotor optimum design method from the blade element momentum theory,and Rotor B,in which the chord length of the tip is extended and the chord length distribution is *** examined performance characteristics and flow fields of the two rotors through wind tunnel experiments and numerical *** results revealed that the maximum output tip speed ratio of Rotor B shifted lower than that of Rotor A,but the maximum output coefficient increased by approximately 38.7%.Rotors A and B experienced a large-scale separation on the hub side,which extended to the mean in Rotor *** difference in separation had an impact on the significant decrease in Rotor A's output compared to the design value and the increase in Rotor B's output compared to Rotor A.

关键词： Wind Turbine Propeller-Type Horizontal Axis Blade Element Momentum Theory Rotor Design Method

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Large Deformation Analysis and Synthesis of Elastic Closed-loop Mechanism Made of a Certain Spring Wire Described by Free Curves

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Chinese Journal of mechanical engineering 2015年第4期28卷 756-762页

作者： IWATSUKI Nobuyuki KOSAKI Takashi department of mechanical Sciences and engineering Graduate School of Science and EngineeringTokyo Institute of Technology

Recently novel mechanisms with compact size and without many mechanical elements such as bearing are strongly required for medical devices such as surgical operation devices. This paper describes analysis and synthesis of elastic link mechanisms of a single spring beam which can be manufactured by NC coiling machines. These mechanisms are expected as disposable micro forceps. Smooth Curvature Model（SCM） with 3rd order Legendre polynomial curvature functions is applied to calculate large deformation of a curved cantilever beam by taking account of the balance between external and internal elastic forces and moments. SCM is then extended to analyze large deformation of a closed-loop curved elastic beam which is composed of multiple free curved beams. A closed-loop elastic link is divided into two free curved cantilever beams each of which is assumed as serially connected free curved cantilever beams described with SCM. The sets of coefficients of Legendre polynomials of SCM in all free curved cantilever beams are determined by taking account of the force and moment balance at connecting point where external input force is applied. The sets of coefficients of Legendre polynomials of a nonleaded closed-loop elastic link are optimized to design a link mechanism which can generate specified output motion due to input force applied at the assumed dividing point. For example, two planar micro grippers with a single pulling input force are analyzed and designed. The elastic deformation analyzed with proposed method agrees very well with that calculated with FEM. The designed micro gripper can generate the desired pinching motion. The proposed method can contribute to design compact and simple elastic mechanisms without high calculation costs.

关键词： elastic link mechanism closed-loop spring beam large deformation analysis smooth curvature model force balance equation synthesi

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MANIPULATION KINEMATICS ON DEXTEROUS HANDS CONSIDERING PURE ROLLING CONTACTS AS PASSIVE JOINTS

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Chinese Journal of mechanical engineering 2005年第3期18卷 361-365页

作者： Yang Yang Tamio Arai school of mechanical engineering and Automation Beihang University Beijing 100083 China department of precision Machinery engineering Graduate School of Engineering The University of Tokyo Tokyo 113-8656 Japan

The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differential kinematics and mobility are studied. The minimal structure for realizing the task motion of the object is obtained, and the conditions for dexterous manipulation are presented. Finally, some rolling manipulations are used as examples to demonstrate the applicability of approach proposed.

关键词： Pure rolling Passive joints Differential kinematics Dexterous hands

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