To improve the inversion accuracy of time-domain airborne electromagnetic data, we propose a parallel 3D inversion algorithm for airborne EM data based on the direct Gauss-Newton optimization. Forward modeling is perf...To improve the inversion accuracy of time-domain airborne electromagnetic data, we propose a parallel 3D inversion algorithm for airborne EM data based on the direct Gauss-Newton optimization. Forward modeling is performed in the frequency domain based on the scattered secondary electrical field. Then, the inverse Fourier transform and convolution of the transmitting waveform are used to calculate the EM responses and the sensitivity matrix in the time domain for arbitrary transmitting waves. To optimize the computational time and memory requirements, we use the EM ＂footprint＂ concept to reduce the model size and obtain the sparse sensitivity matrix. To improve the 3D inversion, we use the OpenMP library and parallel computing. We test the proposed 3D parallel inversion code using two synthetic datasets and a field dataset. The time-domain airborne EM inversion results suggest that the proposed algorithm is effective, efficient, and practical.展开更多
The choice of the particle's distribution model and the consistency of the result are very important for FastSLAM.The improved auxiliary variable model with FastSLAM,and Stirling Interpolation which is used to app...The choice of the particle's distribution model and the consistency of the result are very important for FastSLAM.The improved auxiliary variable model with FastSLAM,and Stirling Interpolation which is used to approximate the nonlinear functions are provided.This approach improves the precision of the approximation for the nonlinear functions,conquers the drawback of the FastSLAM1.0 by using a model ignoring the measurement data,enhances the estimation consistency of the robot pose,and reduces the degradation speed of the particle in FastSLAM algorithm.Simulation results demonstrate the excellence of the proposed algorithm and give the noise parameter influence on the proposed algorithm.展开更多
The human brain is built to process complex visual impressions within milliseconds. In comparison with sequentially coded spoken language and written texts, we are capable of consuming graphical information at a high ...The human brain is built to process complex visual impressions within milliseconds. In comparison with sequentially coded spoken language and written texts, we are capable of consuming graphical information at a high bandwidth in a parallel fashion, producing a picture worth more than a thousand words. Effective information visualization can be a powerful tool to capture people's attention and quickly communicate large amounts of data and complex information. This is particularly important in the context of communication data, which often describes entities (people, organizations) and their connections through communication. Visual analytics approaches can optimize the user-computer interaction to gain insights into communication networks and learn about their structures. Network visualization is a perfect instrument to better communicate the results of analysis. The precondition for effective information visualization and successful visual reasoning is the capability to draw "good" pictures. Even though communication networks are often large, including thousands or even millions of people, underlying visualization principles are identical to those used for visualizing smaller networks. In this article, you will learn about these principles, giving you the ability to assess the quality of network visualizations and to draw better network pictures by yourself.展开更多
A 77-year-old man who had underwent orthopedic surgery 17 days ago due to his left femur frac- ture caused by a pedestrian-car accident came to our emer- gency department with the chief complaint of a 2 days his- tory...A 77-year-old man who had underwent orthopedic surgery 17 days ago due to his left femur frac- ture caused by a pedestrian-car accident came to our emer- gency department with the chief complaint of a 2 days his- tory of sore throat and cough and also swelling of eyelids. He had no respiratory distress or any other life-threatening symptoms. Subsequent physical examination revealed re- markable edema and crepitus over the whole face, neck, proximal upper limbs and the anterior and posterior chest regions, and also bilateral hyperresonance was detected in pulmonary auscultation. The imaging studies showed pneu-momediastinum and bilateral subcutaneous emphysema. The diagnosis of pneumomediastinum and mild left pneumotho- rax and massive subcutaneous emphysema was definitely made. He underwent bilateral tube thoracostomy by using a 32 French chest tube under local anesthesia in the fifth in- tercostal space on the anterior axillary line. The patient was discharged with no complications 10 days postoperatively.展开更多
基金supported by the Key Natural Science Foundation(No.41530320)Natural Science Foundation(No.41274121)+1 种基金Natural Science Foundation for young scientist(No.41404093)the Projects on the Development of the Key Equipment of Chinese Academy of Science(No.ZDYZ2012-1-03)
文摘To improve the inversion accuracy of time-domain airborne electromagnetic data, we propose a parallel 3D inversion algorithm for airborne EM data based on the direct Gauss-Newton optimization. Forward modeling is performed in the frequency domain based on the scattered secondary electrical field. Then, the inverse Fourier transform and convolution of the transmitting waveform are used to calculate the EM responses and the sensitivity matrix in the time domain for arbitrary transmitting waves. To optimize the computational time and memory requirements, we use the EM ＂footprint＂ concept to reduce the model size and obtain the sparse sensitivity matrix. To improve the 3D inversion, we use the OpenMP library and parallel computing. We test the proposed 3D parallel inversion code using two synthetic datasets and a field dataset. The time-domain airborne EM inversion results suggest that the proposed algorithm is effective, efficient, and practical.
基金National High-Tech Research and Development Program of China(No.2003AA1Z2130)Science and Technology Project of Zhejiang Province,China(No.2005C11001-02)
文摘The choice of the particle's distribution model and the consistency of the result are very important for FastSLAM.The improved auxiliary variable model with FastSLAM,and Stirling Interpolation which is used to approximate the nonlinear functions are provided.This approach improves the precision of the approximation for the nonlinear functions,conquers the drawback of the FastSLAM1.0 by using a model ignoring the measurement data,enhances the estimation consistency of the robot pose,and reduces the degradation speed of the particle in FastSLAM algorithm.Simulation results demonstrate the excellence of the proposed algorithm and give the noise parameter influence on the proposed algorithm.
文摘The human brain is built to process complex visual impressions within milliseconds. In comparison with sequentially coded spoken language and written texts, we are capable of consuming graphical information at a high bandwidth in a parallel fashion, producing a picture worth more than a thousand words. Effective information visualization can be a powerful tool to capture people's attention and quickly communicate large amounts of data and complex information. This is particularly important in the context of communication data, which often describes entities (people, organizations) and their connections through communication. Visual analytics approaches can optimize the user-computer interaction to gain insights into communication networks and learn about their structures. Network visualization is a perfect instrument to better communicate the results of analysis. The precondition for effective information visualization and successful visual reasoning is the capability to draw "good" pictures. Even though communication networks are often large, including thousands or even millions of people, underlying visualization principles are identical to those used for visualizing smaller networks. In this article, you will learn about these principles, giving you the ability to assess the quality of network visualizations and to draw better network pictures by yourself.
文摘A 77-year-old man who had underwent orthopedic surgery 17 days ago due to his left femur frac- ture caused by a pedestrian-car accident came to our emer- gency department with the chief complaint of a 2 days his- tory of sore throat and cough and also swelling of eyelids. He had no respiratory distress or any other life-threatening symptoms. Subsequent physical examination revealed re- markable edema and crepitus over the whole face, neck, proximal upper limbs and the anterior and posterior chest regions, and also bilateral hyperresonance was detected in pulmonary auscultation. The imaging studies showed pneu-momediastinum and bilateral subcutaneous emphysema. The diagnosis of pneumomediastinum and mild left pneumotho- rax and massive subcutaneous emphysema was definitely made. He underwent bilateral tube thoracostomy by using a 32 French chest tube under local anesthesia in the fifth in- tercostal space on the anterior axillary line. The patient was discharged with no complications 10 days postoperatively.
