An accurate and computationally efficient model for the deformation of brain tissue is very important in virtual neurosurgical simulation. In this paper, we introduced a new Finite Element Method(FEM) model, which is ...
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An accurate and computationally efficient model for the deformation of brain tissue is very important in virtual neurosurgical simulation. In this paper, we introduced a new Finite Element Method(FEM) model, which is based on optimization implicit Euler method, for brain tissue deformation. Specifically, both the anisotropic and viscoelastic properties of brain tissue are incorporated into the model, providing more realistic and accurate description of the mechanical features of brain tissue. In the meantime, the model is particularly suitable for GPU-based computing, making it possible to achieve real-time performance for neurosurgical simulation. Simulation results show that the deformation model exhibits the behaviors of anisotropy and viscoelasticity. The proposed model was implemented on a neurosurgical simulator and it showed that the deformation of brain tissue can be rendered with a relatively high degree of visual realism at a refreshment rate of 23 frames per second in a normal PC.
The fault diagnosis scheme of the rotor bearing system often conducted by using either signal analysis approach or modeling method. In practice, the structure of the rotor bearing system is complex and contains many n...
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The fault diagnosis scheme of the rotor bearing system often conducted by using either signal analysis approach or modeling method. In practice, the structure of the rotor bearing system is complex and contains many nonlinear factors. Therefore, it is hard to use the model-based method for fault detection. Thus, signal analysis approach is more efficient. In the signal analysis approach, frequency response function is widely applied. However, the existing analyzing methods of frequency response function have some limitations, such as multidimensional property. Thus, in this study, the concept of Nonlinear Response Spectrum Function(NRSF) is proposed to solve the problem. Finally, a simulation is conducted to identify the multi-fault rotor bearing systems by the proposed NRSFs feature and Support Vector Machine(SVM) classifier, showing that the NRSF-SVM approach has an excellent performance in fault identification of rotor bearing system.
We consider the problem of semi-global leader-following output consensus for a group of agents, consisting of a leader agent and some follower agents, which are described by discrete-time linear systems and connected ...
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As the representative of hypersonic vehicles in the near space,X-51 A and HTV-2 with high speed and irregular acceleration often adopt nonballistic maneuver flight motion,which is hard to be accurately *** paper focus...
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ISBN:
(纸本)9781509046584
As the representative of hypersonic vehicles in the near space,X-51 A and HTV-2 with high speed and irregular acceleration often adopt nonballistic maneuver flight motion,which is hard to be accurately *** paper focuses on three typical nonballistic maneuver models of near space targets,and proposes a new Modified Variable Structure Interacting Multiple Model(MVSIMM) *** the three nonballistic maneuver models,simulation results show that the MVSIMM algorithm is better than Fixed-Structure Interacting Multiple Model(FSIMM) filter algorithms.
This work mainly focuses on designing and modeling of 18-pulse autotransformer rectifier unit. The dq rotating reference frame(Park’s Transformation) is used to design the average model. Polynomial fits are require...
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ISBN:
(纸本)9781538604854
This work mainly focuses on designing and modeling of 18-pulse autotransformer rectifier unit. The dq rotating reference frame(Park’s Transformation) is used to design the average model. Polynomial fits are required to build up from essential parameters like α, kv and ki that must be extracted from switching model or actual setup. The designed model is computationally efficient, time invariant and has the key advantage of reduced simulation time, less convergence errors and having no numerical instabilities. The designed average model provides a much more accurate representation of the system dynamics both in frequency as well as in time domain. For this purpose, 18-pulse delta type autotransformer rectifier unit(ATRU) is modeled and analyzed for small signal behavior in order to realize the overall system stability. Finally average model is validated with hardware setup of 2 k VA prototype and its results are found to be closely matching with those of switching and average model proving the accuracy and reliability of the proposed model. Hence using these average models can greatly reduce the time consumption by avoiding mathematical instabilities while maintaining efficiency up to the mark on the other side.
Based on the analysis of the accurate estimation method of the state of charge (SOC) of lithium battery for electric vehicles, aiming at the shortcomings of back propagation (BP) neural network model, an algorithm bas...
Based on the analysis of the accurate estimation method of the state of charge (SOC) of lithium battery for electric vehicles, aiming at the shortcomings of back propagation (BP) neural network model, an algorithm based on Improved Particle Swarm Optimization (IPSO) is proposed to optimize the parameters of BP neural network. In this algorithm, the particle swarm optimization algorithm is optimized by introducing shrinkage factor to limit the particle speed, so as to determine the initial parameters of BP neural network. Finally, the battery estimation model is established by using the data set of lithium battery published by NASA PCoE, and the simulation test is carried out by using MATLAB platform. The results show that the method can effectively reduce the SOC error and control the error within 2%. It has practical significance for SOC estimation in battery management system.
Low-rank Multi-view Subspace Learning (LMvSL) has shown great potential in cross-view classification in recent years. Despite their empirical success, existing LMvSL based methods are incapable of well handling view d...
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The adaptive model predictive control is regarded as an effective control method for unknown constrained ***, the adaptive model predictive control needs model identification. The process of identification demands a c...
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The adaptive model predictive control is regarded as an effective control method for unknown constrained ***, the adaptive model predictive control needs model identification. The process of identification demands a certain amount of data and places some requirements on data which makes it difficult to be implemented. To handle it, this paper proposes a novel data-driven approach without model identification. The data of previous time is utilized to describe state space and input space of the uncertain system instead of identifying the true model. Based on the data-driven method, the Quasi-MinMax control strategy is used to design the robust data-driven MPC controller which directly calculates the input from the past data. Combined with the data-driven method, a free control variable is introduced to compensate for the insufficiency of past data. It is shown that adopting the data-driven controller can reduce conservatism by lessening model uncertainty and improve control performance. Meanwhile, the proposed design is proven to be recursively feasible and stabilizing. A numerical example demonstrates the effectiveness and advantages of the proposed control method.
This paper presents issues regarding short term electric load forecasting using feedforward and Elman recurrent neural networks. The study cases were developed using measured data representing electrical energy consum...
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Soft robotics has advanced the field of biomedical engineering by creating safer technologies for interfacing with the human body. One of the challenges in this field is the realization of modular soft basic constitue...
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Soft robotics has advanced the field of biomedical engineering by creating safer technologies for interfacing with the human body. One of the challenges in this field is the realization of modular soft basic constituents and accessible assembly methods to increase the versatility of soft robots. We present a soft pneumatic actuator composed of two elastomeric strands that provide interdependent axial and radial expansion due to the modularity of the components and their helical arrangement. The actuator reaches 35% of elongation with respect to its initial height and both chambers achieve forces of 1N at about 19kPa. We describe the design, fabrication, modeling and benchtop testing of the soft actuator towards realizing 3D functional structures with potential medical applications. An example of application for soft medical robots is tissue regenerative for the long-gap esophageal atresia condition.
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