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computational model for perception of objects and motions

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Science China(Life Sciences) 2008年第6期51卷 526-536页

作者： YANG WenLu1,2, ZHANG LiQing1 & MA LiBo1 1 Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China 2 Department of Electronic Engineering, Shanghai Maritime University, Shanghai 200135, China Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai China Department of Electronic Engineering Shanghai Maritime University Shanghai China

Perception of objects and motions in the visual scene is one of the basic problems in the visual system. There exist 'What' and 'Where' pathways in the superior visual cortex, starting from the simple cells in the primary visual cortex. The former is able to perceive objects such as forms, color, and texture, and the latter perceives 'where', for example, velocity and direction of spatial movement of objects. This paper explores brain-like computational architectures of visual information processing. We propose a visual perceptual model and computational mechanism for training the perceptual model. The compu- tational model is a three-layer network. The first layer is the input layer which is used to receive the stimuli from natural environments. The second layer is designed for representing the internal neural information. The connections between the first layer and the second layer, called the receptive fields of neurons, are self-adaptively learned based on principle of sparse neural representation. To this end, we introduce Kullback-Leibler divergence as the measure of independence between neural responses and derive the learning algorithm based on minimizing the cost function. The proposed algorithm is applied to train the basis functions, namely receptive fields, which are localized, oriented, and bandpassed. The resultant receptive fields of neurons in the second layer have the characteristics resembling that of simple cells in the primary visual cortex. Based on these basis functions, we further construct the third layer for perception of what and where in the superior visual cortex. The proposed model is able to perceive objects and their motions with a high accuracy and strong robustness against additive noise. Computer simulation results in the final section show the feasibility of the proposed perceptual model and high efficiency of the learning algorithm.

关键词： visual perception visual cortex computational model receptive fields simple cells complex cells

computational Fluid Dynamics Benchmark of an Impulse Turbine with Fixed Guide Vanes

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Journal of Thermal Science 2004年第2期13卷 109-113,108页

作者： Ajit THAKKER Fergal HOURIGAN T. SETOGUCHI M. TAKAO Wave Energy Research Team Department of Mechanical and Aeronautical Engineering University of Limerick Limerick IrelandWave Energy Research Team Department of Mechanical and Aeronautical Engineering University of Limerick Limerick IrelandDepartment of Mechanical Engineering Saga University 1 Honjo-machi Saga-shi Saga 840-8502 JapanDepartment of Control Engineering Matsue National College of Technology 14-4 Nishiikuma-cho Matsue-shi Shimane 690-8518 Japan

This paper presents the comparison of a three dimensional computational Fluid Dynamics (CFD) analysis with empirical performance data of a 0.6 m impulse turbine with fixed guide vanes used for wave energy power conversion. Pro-Engineer, Gambit and Fluent 6 were used to create a 3-D model of the turbine. A hybrid meshing scheme was used with hexahedral cells in the near blade region and tetrahedral and pyramid cells in the rest of the domain. The turbine has a hub-to-tip ratio of 0.6 and results were obtained over a wide range of flow coefficients. The model yielded a maximum efficiency of approximately 54% as compared to a maximum efficiency of around 49% from experiment. A degree of insight into flow behaviour, not possible with experiment, was obtained.

关键词： wave energy impulse turbine computational fluid dynamics CFD hybrid mesh.

computational chemical engineering–Towards thorough understanding and precise application

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Chinese Journal of Chemical Engineering 2016年第8期24卷 945-951页

作者： Zaisha Mao Chao Yang Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences

The paradigms of chemical engineering discipline are discussed. The first paradigm of Unit Operations and the second paradigm of Transport Phenomena are well recognized among the chemical engineers all over the world, and what the next paradigm is remains still an open question. Several proposals such as Chemical product engineering, Sustainable chemical engineering and Multi-scale methodology are considered as candidates for next paradigm. Might computational Chemical Engineering be the next one, which is advancing the discipline of chemical engineering toward ultimate mechanism-based understanding of chemical processes? This possibility is comparatively expounded with other proposals, and the scope and depth of computational chemical engineering are shortly listed.

关键词： Paradigm Unit operations Transport phenomena Chemical product engineering Sustainable chemical engineering computational chemical engineering Numerical simulation

computational neuroscience in China

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Science China(Life Sciences) 2010年第3期53卷 385-397页

作者： WU Si1 & LIANG PeiJi2 1Institute of Neuroscience,Shanghai Institutes for Biological Sciences,State Key Laboratory of Neurobiology,Chinese Academy of Sciences,Shanghai 200031,China 2Department of Biomedical Engineering,Shanghai Jiaotong University,Shanghai 200240,China Institute of Neuroscience Shanghai Institutes for Biological Sciences State Key Laboratory of Neurobiology Chinese Academy of Sciences Shanghai China Department of Biomedical Engineering Shanghai Jiaotong University Shanghai China

The ultimate goal of computational Neuroscience(CNS) is to use and develop mathematical models and approaches to elucidate brain functions.CNS is a young and highly multidisciplinary field.It heavily interacts with experimental neuroscience and such other research areas as artificial intelligence,robotics,computer vision,information science and machine learning.This paper reviews the history of CNS in China,its current status and the prospects for its future development.Examples of CNS research in China are also presented.

关键词： computational neuroscience experimental neuroscience artificial intelligence

computational pharmacological studies on cardiovascular disease by Qishen Yiqi Diwan

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Science China Chemistry 2009年第11期52卷 1871-1878页

作者： GU JiangYong YUAN Gu ZHU YongHong XU XiaoJie Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Academy of Tasly Pharmaceutical Co. LTDTianjin 300410China

computational pharmacological methods were used to study the distribution of 1729 compounds contained in a Chinese medicine,Qishen Yiqi Diwan,in chemical space.The results show that most of these compounds have good drug-like properties.Molecular docking was used to study the interactions between 1729 compounds of Qishen Yiqi Diwan and 26 drug targets related to cardiovascular disease and the distribution of 1729 compounds in drug-target space.The results may shed light on the action mechanism and the search for the active compounds in Qishen Yiqi Diwan.

关键词： chemical space drug-target space molecular docking computational pharmacology

computational investigation of hydraulic performance variation with geometry in gabion stepped spillways

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Water Science and Engineering 2019年第1期12卷 62-72页

作者： Dominic E.Reeve Ali Adel Zuhaira Harshinie Karunarathna College of Engineering Swansea University

Over recent years, there has been a clear increase in the frequency of reported flooding events around the world. Gabion structures offer one means of flood mitigation in dam spillways. These types of structures provide an additional challenge to the computational modeller in that flow through the porous gabions must be simulated. We have used a computational model to investigate the flow over gabion stepped spillways. The model was first validated against published experimental results. Then, gabion stepped spillways with four different step geometries were tested under the same conditions in order to facilitate inter-comparisons and to choose the best option in terms of energy dissipation. The results show that normal gabion steps can dissipate more energy than overlap, inclined, and pooled steps. An intensive set of tests with varying slope, stone size, and porosity were undertaken. The location of the inception point and the water depth at this point obtained from this study were compared with those from existing formulae. Two new empirical equations have been derived, on the basis of a regression analysis, to provide improved results for gabion stepped spillways.

关键词： computational modelling Energy dissipation Gabion stepped spillways Inception point location Skimming flow

computational fluid dynamics simulation of a novel bioreactor forsophorolipid production

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Chinese Journal of Chemical Engineering 2017年第6期25卷 732-740页

作者： Xiaoqiang Jia Lin Qi Yaguang Zhang Xue Yang Hongna Wang Fanglong Zhao Wenyu Lu Department of Biochemical Engineering School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China Key Laboratory of Systems Bioengineering (Tianjin University) Ministry of Education Tianjin 300072 China Synthetic Biology Platform Collaborative Innovation Center of Chemical Science and Engineering (Tiarljin) Tianjin 300072 China

This paper describes three-dimensional computational fluid dynamics(CFD) simulations of gas–liquid flow in a novel laboratory-scale bioreactor contained dual ventilation-pipe and double sieve-plate bioreactor(DVDSB)used for sophorolipid(SL) production. To evaluate the role of hydrodynamics in reactor design, the comparisons between conventional fed-batch fermenter and DVDSB on the hydrodynamic behavior are predicted by the CFD methods. Important hydrodynamic parameters of the gas–liquid two-phase system such as the liquid phase velocity field, turbulent kinetic energy and volume-averaged overall and time-averaged local gas holdups were simulated and analyzed in detail. The numerical results were also validated by experimental measurements of overall gas holdups. The yield of sophorolipids was significantly improved to 484 g·L^(-1)with a 320 h fermentation period in the new reactor.

关键词： Bioreactors Gas hold-up computational fluid dynamics (CFD)Hydrodynamics Sophorolipid production

computational systems biology for omics data analysis

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Journal of Molecular Cell Biology 2019年第8期11卷 631-632页

作者： Luonan Chen Key Laboratory of Systems Biology Center for Excellence in Molecular Cell Science Shanghai Institute of Biochemistry and Cell Biology Chinese Academy of Sciences Shanghai 200031 China

Recent trend on biological data at a molecular level is omics data analysis for both bulk and single cells, in eluding genomics, proteomics, metabolomics, and epigenetics data (Wang and Zhang, 2017;Zhang et al., 2017;Zhao and Li, 2017;Cheng and Leung, 2018). Rapid accumulation of such high-dimensional biological data is driving the system-level study from describing complex phenomena to understanding molecular mechanisms (Park et al., 2018;Sun et al., 2018) and from analyzi ng in dividual components to understanding their networks and systems (Chen et al., 2009;Chen, 2017).

关键词： computational systems biology omics data analysis

computational fluid dynamics simulation of Hyperloop pod predicting laminar–turbulent transition

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Railway Engineering Science 2020年第1期28卷 97-111页

作者： Nathalie Nick Yohei Sato Department of Mechanical and Process Engineering Swiss Federal Institute of TechnologyETH ZurichLEO B 9.1Leonhardstrasse 278092 ZurichSwitzerland Nuclear Energy and Safety Research Division Paul Scherrer InstituteForschungsstrasse 1115232 Villigen PSISwitzerland

Three-dimensional compressible flow simulationswere conducted to develop a Hyperloop pod. Thenovelty is the usage of Gamma transition model, in whichthe transition from laminar to turbulent flow can be predicted.First, a mesh dependency study was undertaken,showing second-order convergence with respect to themesh refinement. Second, an aerodynamic analysis for twodesigns, short and optimized, was conducted with thetraveling speed 125 m/s at the system pressure 0.15 bar.The concept of the short model was to delay the transitionto decrease the frictional drag;meanwhile that of theoptimized design was to minimize the pressure drag bydecreasing the frontal area and introduce the transitionmore toward the front of the pod. The computed resultsshow that the transition of the short model occurred moreon the rear side due to the pod shape, which resulted in 8%smaller frictional drag coefficient than that for the optimizedmodel. The pressure drag for the optimized designwas 24% smaller than that for the short design, half ofwhich is due to the decrease in the frontal area, and theother half is due to the smoothed rear-end shape. The totaldrag for the optimized model was 14% smaller than that forthe short model. Finally, the influence of the systempressure was investigated. As the system pressure and theReynolds number increase, the frictional drag coefficientincreases, and the transition point moves toward the front,which are the typical phenomena observed in the transitionregime.

关键词： computational fluid dynamics(CFD) Drag Subsonic compressible flow Hyperloop Laminar-turbulent transition