We consider the inverse electrocardiographic problem of computing epicardial potentials from a body-surface potential map. We study how to improve numerical approximation of the inverse problem when the finite-element method is used. Being ill-posed, the inverse problem requires different discretization strategies from its corresponding forward problem. We propose refinement guidelines that specifically address the ill-posedness of the problem. The resulting guidelines necessitate the use of hybrid finite elements composed of tetrahedra and prism elements. Also, in order to maintain consistent numerical quality when the inverse problem is discretized into different scales, we propose a new family of regularizers using the variational principle underlying finite-element methods. These variational-formed regularizers serve as an alternative to the traditional Tikhonov regularizers, but preserves the L2 norm and thereby achieves consistent regularization in multiscale simulations. The variational formulation also enables a simple construction of the discrete gradient operator over irregular meshes, which is difficult to define in traditional discretization schemes. We validated our hybrid element technique and the variational regularizers by simulations on a realistic 3-D torso/heart model with empirical heart data. Results show that discretization based on our proposed strategies mitigates the ill-conditioning and improves the inverse solution, and that the variational formulation may benefit a broader range of potential-based bioelectric problems.
The construction skill of vernacular landscape in the country park was studied from analyzing and summarizing the concept of vernacular landscape.Five key points were put forward:minimizing the degree of human intervention to create a pleasant-scale space;reappearing idyllic scenery to produce beautiful landscape;creating a diverse ecosystem to provide a rich habitat for living beings;interpreting local culture to find the spiritual home;sharing the harvest scene to produce vital atmosphere.Taking Shengtianhu Wet-land Park in Shanxi Province as an example,based on the investigation and planning of the current conditions,nine functional areas were designed to create the beautiful idyllic scenery to provide useful references for future designing of vernacular landscape in country park.
This paper researches how physical layer influences the signal reflection of the CAN bus is carried on in both theory and experimental ways. In order to analyze the problems in engineering applies of CAN network, and to bring forward the methods to solve them. In this way, reference can be provided for the design of the communication based on CAN bus in the future.
When the motor works normally, its base will vibrate. The structure will generate the resonance and result in damage of the mechanical equipment when the vibration frequency reaches the natural frequency. The article which is based on the modal analysis of the motor base compares the natural frequencies in different boundary constraints in order to select appropriate way to install the motor base, and optimizes the motor base by contrasting different effects on the natural frequencies of the different thickness of the ribbed plates for selecting reasonable structure to prevent resonance.
The Application of Electric Vehicle (EV) has been limited by the problems of power battery. Battery Quick Change System was used efficiently to solve these problems. Based on wireless transceiver nRF905 and single chip MC68HC908GZ16, the wireless communication module was designed for the BQCS, which was used on battery cases quick changing of pure electric bus. The remote-control, quick location, automatic unlocking and manual/automatic mode change were realized. The system was applied on the buses for Beijing Olympic Games. Results indicate that the system shows stably and reliably operation qualities and meets the requirements of the pure electric buses.
Image inpainting is a means of inferring the content of the missing information based on the remaining information of the image, and inpainting the missing information, requiring the inpainted image to meet the human eye perception to the greatest extent. The image inpainting method based on the weight function takes arbitrary points for inpainting during inpainting, which results in poor inpainting effect at the junction of objects. Therefore, this paper adds the priority values calculation of inpainting points to improve the inpainting effect. Finally, comparing the inpainted image based on the priority calculation with the previous one, the inpainting effect at the boundary of the object is significantly better than the image inpainting method based solely on the weight functions.
Self-attention has been proven to be a quite powerful yet calculation-intensive method for scene semantic segmentation. Even though many efforts have been made to explore more effective and resource-saving ways to apply self-attention, there is still space in reducing the calculation consumption. Meanwhile, since self-attention is good at fusing information, its application should be extended to multi-scale-feature-fusion, which is barely researched while the information exchange paths between features in different resolutions are mostly addition and concatenation. A special partition method decreasing the computational complexity of self-attention is investigated, and a multi-scale-feature-attention (MFA) module fusing low-resolution features containing semantic information with high-resolution features having detailed information is presented at the same time. To be specific, the proposed multi-scale-partition-attention (MPA) module and MFA module are inserted into the backbone in sequence to fuse information among all the pixels in one highly extracted feature and the pixels from features with different resolutions, respectively. Extensive experiments are carried out on semantic segmentation benchmarks including PASCAL-Context and Cityscapes to demonstrate that these two improved modules can improve the performance of the backbone in scene semantic segmentation tasks that contain multiple classes and objects in both big and small sizes.
This paper carries out the conceptual design of motor control system based on the standard of functional safety ISO 26262 for new energy vehicle. First, the paper introduce the main contents of the concept phase of ISO 26262. Then, the paper complete the item definition, hazard analysis and risk assessment of motor control system, and determine the functional safety goal and functional safety requirements.
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