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Actor-Critic Reinforcement Learning and Application in Developing Computer-Vision-Based interface tracking

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Engineering 2021年第9期7卷 1248-1261页

作者： Oguzhan Dogru Kirubakaran Velswamy Biao Huang Department of Chemical and Materials Engineering University of AlbertaEdmontonAB T6G 1H9Canada

This paper synchronizes control theory with computer vision by formalizing object tracking as a sequential decision-making process.A reinforcement learning(RL)agent successfully tracks an interface between two liquids,which is often a critical variable to track in many chemical,petrochemical,metallurgical,and oil *** method utilizes less than 100 images for creating an environment,from which the agent generates its own data without the need for expert *** supervised learning(SL)methods that rely on a huge number of parameters,this approach requires far fewer parameters,which naturally reduces its maintenance *** its frugal nature,the agent is robust to environmental uncertainties such as occlusion,intensity changes,and excessive *** a closed-loop control context,an interface location-based deviation is chosen as the optimization goal during *** methodology showcases RL for real-time object-tracking applications in the oil sands *** with a presentation of the interface tracking problem,this paper provides a detailed review of one of the most effective RL methodologies:actor–critic policy.

关键词： interface tracking Object tracking Occlusion Reinforcement learning Uniform manifold approximation and projection

NUMERICAL SIMULATION OF THE FLOW WITH CONTACT LINES

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Acta Mechanica Sinica 1997年第3期13卷 210-217页

作者：卢作伟崔桂香张兆顺 Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China

The paper proposes a physical model for the motion of the contact line and the gas-liquid interface. The local motion of the contact line at the solid wall is assumed and the interface between gas and liquid is traced by a level function. The finite volume method and staggered grids are used to solve the governing equation numerically. The motion of the water column in a vertical pipe is computed and the results are in good agreement with experimental data.

关键词： numerical simulation motion of contact line interface tracking

Numerical studies of penetration problems by an improved particle method

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Science China(Physics,Mechanics & Astronomy) 2012年第12期55卷 2273-2283页

作者： REN HuiLan MA TianBao YAO XiaoHu State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Department of Engineering Mechanics School of Civil Engineering and TransportationSouth China University of TechnologyGuangzhou 510640China

A particle mapping transportation algorithm was proposed on the basis of the particle-in-cell *** particles with rectangular influence domains were employed in the transportation algorithm to reduce the numerical *** on the error analysis in the process of particle motion computation,a prediction-correction algorithm was introduced to improve the computational ***,the performance of the particle mapping transportation method was evaluated by using the rotation,the slotted disk and the shear advection tests,and the results were compared with other interface reconstruction ***,the hemispherical projectile penetration into a steel target was numerically *** results showed that the proposed method produced less numerical fluctuations and exhibited clear material interfaces,which indicated that it is accurate and effective.

关键词： numerical simulation particle-in-cell particle mapping transportation method interface tracking penetration

The Numerical Simulation of the Flow with Contact Lines

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Communications in Nonlinear Science and Numerical Simulation 1996年第3期1卷 50-56页

作者： Zuowei LU Guixiang CUI Zhaoshun ZHANG(Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China )E-mail: demzzs@*** Department of Engineering Mechanics Tsinghua University Beijing 100084 P. R. China

The paper proposes a physical model for tracking the motion of the contactline and the gas-liquid interface. The local motion of the contact line at the solid wall isassumed and the interface between gas and liquid is trared by a level function. The finitevolume method and staggered grids are used to solve the governing equation numericallyThe motion of the water column in a vertical pipe is computed and the results are comparedwith experimental data in good agreement.

关键词： numerical simulation motion of contact line interface tracking

A Moving-Mesh Finite Element Method and its Application to the Numerical Solution of Phase-Change Problems

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Communications in Computational Physics 2009年第8期6卷 595-624页

作者： M.J.Baines M.E.Hubbard P.K.Jimack R.Mahmood Department of Mathematics The University of ReadingUK School of Computing University of LeedsUK Computer Division Pakistan Institute of Nuclear Science and Technology(PINSTECH)IslamabadPakistan

A distributed Lagrangian moving-mesh finite element method is applied to problems involving changes of *** algorithm uses a distributed conservation principle to determine nodal mesh velocities,which are then used to move the *** nodal values are obtained from an ALE(Arbitrary Lagrangian-Eulerian)equation,which represents a generalization of the original algorithm presented in Applied Numerical Mathematics,54:450–469(2005).Having described the details of the generalized algorithm it is validated on two test cases from the original paper and is then applied to one-phase and,for the first time,two-phase Stefan problems in one and two space dimensions,paying particular attention to the implementation of the interface boundary *** are presented to demonstrate the accuracy and the effectiveness of the method,including comparisons against analytical solutions where available.

关键词： Moving mesh method finite elements multiphase flows interface tracking

A Hybrid Immersed interface Method for Driven Stokes Flow in an Elastic Tube

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Numerical Mathematics(Theory,Methods and Applications) 2013年第4期6卷 600-616页

作者： Yi Li Sarah A.Williams Anita T.Layton Department of Mathematics Duke UniversityDurhamNC 27708-0320USA

We present a hybrid numerical method for simulating fluid flow through a compliant,closed tube,driven by an internal source and *** is assumed to be highly viscous with its motion described by Stokes *** geometry is assumed to be axisymmetric,and the governing equations are implemented in axisymmetric cylindrical coordinates,which capture 3D flow dynamics with only 2D *** solve the model equations using a hybrid approach:we decompose the pressure and velocity fields into parts due to the surface forcings and due to the source and sink,with each part handled separately by means of an appropriate *** the singularly-supported surface forcings yield an unsmooth solution,that part of the solution is computed using the immersed interface *** conditions are derived for the axisymmetric cylindrical *** velocity due to the source and sink is calculated along the tubular surface using boundary *** results are presented that indicate second-order accuracy of the method.

关键词： Stokes flow interface tracking immersed interface methods axisymmetric cylindrical coordinates boundary integrals

Application of Gridless Method to Simulation of Compressible Multi-Material Flows

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Journal of Harbin Institute of Technology(New Series) 2015年第6期22卷 103-109页

作者： Liang Wang Houqian Xu Wei Wu Rui Xue School of Energy and Power Engineering Nanjing University of Science & Technology

The least-square gridless method was extended to simulate the compressible multi-material flows. The algorithm was accomplished to solve the Arbitrary Lagrange-Euler( ALE) formulation. The local least-square curve fits was adopted to approximate the spatial derivatives of a point on the base of the points in its circular support domain,and the basis function was linear. The HLLC( Harten-Lax-van Leer-Contact) scheme was used to calculate the inviscid flux. On the material interfaces,the gridless points were endued with a dual definition corresponding to different materials. The moving velocity of the interface points was updated by solving the Riemann problem. The interface boundary condition was built by using the Ghost Fluid Method( GFM).Computations were performed for several one and two dimensional typical examples. The numerical results show that the interface and the shock wave are well captured,which proves the effectiveness of gridless method in dealing with multi-material flow problems.

关键词： multi-material flow interface tracking gridless method ALE formulation

Marker-Based,3-D Adaptive Cartesian Grid Method for Multiphase Flow Around Irregular Geometries

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Communications in Computational Physics 2009年第1期5卷 1-41页

作者： Eray Uzgoren Jaeheon Sim Wei Shyy Department of Mechanical Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA24060USA Department of Aerospace Engineering University of MichiganAnn ArborMI48109USA

Computational simulations of multiphase flow are challenging because many practical applications require adequate resolution of not only interfacial physics associated with moving boundaries with possible topological changes,but also around three-dimensional,irregular solid *** this paper,we highlight recent efforts made in simulating multiphase fluid dynamics around complex geometries,based on an Eulerian-Lagrangian *** approach uses two independent but related grid layouts to track the interfacial and solid boundary conditions,and is capable of capturing interfacial as well as multiphase *** particular,the stationary Cartesian grid with time dependent,local adaptive refinement is utilized to handle the computation of the transport equations,while the interface shape and movement are treated by marker-based triangulated surface meshes which freely move and interact with the Cartesian *** markers are also used to identify the location of solid boundaries and enforce the no-slip condition *** related to the contact line treatment,topological changes of multiphase fronts during merger or breakup of objects,and necessary data structures and solution techniques are also *** test cases including spacecraft fuel tank flow management and liquid plug flow dynamics are presented.

关键词： Multiphase flows irregular geometry interface tracking adaptive Cartesian grid non-conforming boundary methods contact line treatment