作者机构：
[Li, Linsheng; Zeng, Li; Liu, Linghui] Chongqing Univ, Educ Minist China, ICT Res Ctr, Key Lab Optoelect Technol & Syst, Chongqing 400044, Peoples R China.;[Zeng, Li] Chongqing Univ, Coll Math & Stat, Chongqing 400044, Peoples R China.;[Li, Linsheng; Zhu, Hongmei; Qiu, Changjun] Univ S China, Coll Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Zeng, Li] C;Chongqing Univ, Coll Math & Stat, Chongqing 400044, Peoples R China.
关键词：
3D image segmentation;Active contour;C-V model;Image processing;Robust statistics
摘要：
The segmentation of 3D images has important applications in the non-destructive examination of industrial computed tomography (CT) and has been widely studied. When a C-V model is used to segment the image, closed and accurate object contours can be obtained. The C-V model is suitable for image segmentation and extended easily to a 3D application. However, industrial CT images may have artifacts or noise, which may make active contours stop at undesired boundaries. In order to overcome these difficulties, the 3D C-V model is improved by the robust statistics method. In this improved model, the intensity of the image in the 3D C-V model is replaced with robust statistics, which is the weighted combination of the inter-quartile range, mean absolute deviation and intensity median in the local region of the image. Inter-quartile range and mean absolute deviation in the local region are introduced to sharpen object boundaries, and the intensity median in the local region reduces image noise. The comparison experiments demonstrate the position accuracy of the contours and robustness to noise of the improved model.
期刊：
Applied Mechanics and Materials,2012年148-149:286-290 ISSN：1660-9336
通讯作者：
Li, L.S.(linshengli_dr@sina.com)
作者机构：
[LI LinSheng; QIU ChangJun; LI Lan] School of Mechanical Engineering, University of South China, Hengyang 421001, China
通讯机构：
[Li, L.S.] S;School of Mechanical Engineering, , Hengyang 421001, China
会议名称：
2011 International Conference on Machanical Engineering,Materials and Energy(2011年机械工程、材料与能源国际会议 ICMEME 2011)
会议时间：
2011-10-19
会议地点：
大连
会议论文集名称：
2011 International Conference on Machanical Engineering,Materials and Energy(2011年机械工程、材料与能源国际会议 ICMEME 2011)论文集
关键词：
Extended finite element method (XFEM);Gaussian integral;Integration scheme
摘要：
A simple integration scheme is presented for numerical integration in the extended finite element method(XFEM). In this scheme, the integral domain of common triangular mesh is converted to that of standard triangular mesh and the integral domain of standard triangular mesh is converted to that of quadrilateral mesh. By this transformation of integral domain, the strength intensity factors for straight crack are worked out. Finally, the accuracy of this method is analyzed by a typical example. It is concluded that the results obtained by new integral scheme are more accurate and simple than common Gaussian integration scheme.
摘要：
In hydraulic system of injection machine, electro-hydraulic proportional flow valve is used to change complex variable pump output flow and power in order to adapt to load change and energy saving.In this paper ,it introduces the working principle of electro-hydraulic proportional flow valve and how control the complex variable pump. Mathematical modeling of proportional flow valve is built and simulations based on Matlabsimulink software is done. It analyses dynamic characteristics of complex variable pump in different electricity. The results are helpful in improving the pump efficiency and response,and they provide theoretical basis for energy saving.
摘要：
Intensity inhomogeneity may cause considerable difficulties in segmentation of CT image. In order to overcome the difficulties caused by intensity inhomogeneity, the region-scalable fitting (RSF) model was put forward. RSF model draws upon intensity information in local regions with a controllable scale. But only using intensity information may lead to slow convergence rate and poor denoise ability. Combining the method of robust statistics, RSF model is improved in this paper. In the improved model, the intensity in RSF model is replaced with local robust statistics which is the weighted combination of inter-quartile range, mean absolute deviation and intensity median in local region. Inter-quartile range and mean absolute deviation in local region are introduced to sharpen object boundaries, and intensity median in local region is introduced to reduce image noise. The contrast experiments between RSF model and the improved model are provided, which demonstrate the fast convergence rate and robustness to noise of the improved model.
摘要：
In this paper a new control method has been studied in which PID control system was integrated into the neural network. It could overcome some disadvantages such as neural network’s slow rate of convergence and PID’s difficulty in application of multivariate nonlinear systems. A controller of the Electro-hydraulic proportional control stroking mechanism for radial piston pump was designed based on the PID neural network control algorithm. The system responses of system variable control signal of system track were achieved by computer simulation. It was found by PIDNN that the control system could reach steady state in a shorter time, compared with PID control system response time by 65% to 80%. The simulation results showed that the controller for the Electro-hydraulic proportional Radial Piston Pump based PID neural network control algorithm would have a good controlling performance.
摘要：
（Fe3Co）80-x Nb4Al2Si4B10Smx、Fe57-xCo18Nb4Al2Si4B15Smx和Fe42.5Co42.5Nb7-xB8Smxamorphous alloy ribbons with the same thickness were prepared by vacuum arc melting and melt spinning. The influence of Sm addition on the amorphous forming ability and phase composition of as-spun alloys were studied by XRD, DTA. The results showed that, the addition of small amount of Sm improved the amorphous forming ability and made the phase composition of as-spun alloys simpler. And with the increasing of Sm contents, the intensity of the peaks corresponding to the formation of （CoFe） 3Nb phase, （FeCo） 3 B phase and B6 （FeCo）23 phase decreased and the precipitated of α - （FeCo） phase decreased apparently, while the amorphous forming ability of alloys increased.
