设计了一种具有高功率容量的高功率微波(high power microwave,HPM)耦合测量装置。该装置使用截止波导对HPM信号取样,并经过同轴探针将取样信号耦合到同轴电缆中。截止波导可以限制进入耦合单元的射频功率,同时,截止波导和传输高功率微...设计了一种具有高功率容量的高功率微波(high power microwave,HPM)耦合测量装置。该装置使用截止波导对HPM信号取样,并经过同轴探针将取样信号耦合到同轴电缆中。截止波导可以限制进入耦合单元的射频功率,同时,截止波导和传输高功率微波的主波导连接处允许大的倒角,因此,该耦合装置能够保证较高的功率容量。此外,通过调节截止波导中探针的长度,可以实现不同的耦合度,容易满足不同功率水平HPM测量的应用需求。与传统的耦合器相比,所设计的耦合器结构简单且功率容量高,其可行性已经得到了HPM实验的证实。展开更多
针对现有的激光里程计在面临室外大场景建图时,普遍会出现定位精度低、鲁棒性差的问题,提出一种16线激光雷达和惯性测量单元(inertial measurement unit, IMU)紧耦合的同时定位与建图(simultaneous localization and mapping, SLAM)算...针对现有的激光里程计在面临室外大场景建图时,普遍会出现定位精度低、鲁棒性差的问题,提出一种16线激光雷达和惯性测量单元(inertial measurement unit, IMU)紧耦合的同时定位与建图(simultaneous localization and mapping, SLAM)算法。首先,对IMU进行估计位姿,通过线性插值矫正激光点云的运动畸变;其次,通过曲率提取场景特征,并根据不同特征性质进行分类;再次,利用帧间匹配模块在滑动窗口内构建局部地图;最后,利用帧与局部地图匹配得到的距离和IMU数据构建联合优化函数。借助KITTI数据集和自行录制的园区数据集,对改进算法与主流的Lego-LOAM和同样使用紧耦合方案的LIO-Mapping进行分模块和整个系统的精度评定。实测结果表明,在符合里程计实时性的要求下,改进激光里程计精度高于Lego-LOAM和LIO-Mapping方案。展开更多
Accurate navigation is important for long-range rocket projectile＇s precise striking. To obtain stable and high-per- formance navigation result, a ultra-tight global positioning system/inertial navigation system （GP...Accurate navigation is important for long-range rocket projectile＇s precise striking. To obtain stable and high-per- formance navigation result, a ultra-tight global positioning system/inertial navigation system （GPS/INS） integration based nav- igation approach is proposed. The accurate short-time output of INS is used by GPS receiver to assist in acquisition of signal, and output information of INS and GPS is fused based on federated filter. Meanwhile, the improved cubature Kalman filter with strong tracking ability is chosen to serve as the local filter, and then the federated filter is enhanced based on vector sharing theory. Finally, simulation results show that the navigation accuracy with the proposed method is higher than that with traditional methods. It provides reference for long-range rocket projectile navigation.展开更多
In the work of developing extrinsic fabry perot interferometric (EFPI), the key technology of polishing fiber optic endfaces and coating the multilayer of dielectric films on them is raised and resolved to settle the...In the work of developing extrinsic fabry perot interferometric (EFPI), the key technology of polishing fiber optic endfaces and coating the multilayer of dielectric films on them is raised and resolved to settle the disturbance and stability problem of EFPI, which simplifies the sensing system, improves the sensor performance and reduces the cost. In this paper, the relations between the output interferential light intensity and the F P cavity length are calculated based on the theory of mode field coupling. The EFPI fiber optic sensor is adhered to a distributed smart laminate beam to detect vibration frequency and axial strain value, the results coincident with the results tested by PZT.展开更多
Though Unified Modeling Language (UML) has been widely used in software development, the major problems confronted lie in comprehension and testing. Dependence analysis is an important approach to analyze, understand,...Though Unified Modeling Language (UML) has been widely used in software development, the major problems confronted lie in comprehension and testing. Dependence analysis is an important approach to analyze, understand, test and maintain programs. A new kind of dependence analysis method for UML class diagrams is developed. A set of dependence relations is definedcorresponding to the relations among classes. Thus, the dependence graph of UML class diagram can be constructed from these dependence relations. Based on this model, both slicing and measurement coupling are further given as its two applications.展开更多
A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, ...A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, and one capacitance sensor for measuring the aperture of the small blind holes or through holes is introduced. The system is composed of one positioning device, one aperture measuring capacitance sensor, one measuring circuit, and software. This system employs visual CCD and two-dimensional mic...展开更多
A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed cou...A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering.展开更多
Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transform...Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.展开更多
Gravitational contributions to the running of gauge couplings are calculated by using different regularizationschemes.As the β function concerns counter-terms of dimension four, only quadratic divergences from the gr...Gravitational contributions to the running of gauge couplings are calculated by using different regularizationschemes.As the β function concerns counter-terms of dimension four, only quadratic divergences from the gravitationalcontributions need to be investigated.A consistent result is obtained by using a symmetry-preserving loop regularizationwith string-mode regulators which can appropriately treat the quadratic divergences and preserve non-abelian gaugesymmetry.The harmonic gauge condition for gravity is used in both diagrammatical and background field calculations,the resulting gravitational corrections to the β function are found to be nonzero, which is different from previous resultspresented in the existing literatures.展开更多
文摘设计了一种具有高功率容量的高功率微波(high power microwave,HPM)耦合测量装置。该装置使用截止波导对HPM信号取样,并经过同轴探针将取样信号耦合到同轴电缆中。截止波导可以限制进入耦合单元的射频功率,同时,截止波导和传输高功率微波的主波导连接处允许大的倒角,因此,该耦合装置能够保证较高的功率容量。此外,通过调节截止波导中探针的长度,可以实现不同的耦合度,容易满足不同功率水平HPM测量的应用需求。与传统的耦合器相比,所设计的耦合器结构简单且功率容量高,其可行性已经得到了HPM实验的证实。
文摘针对现有的激光里程计在面临室外大场景建图时,普遍会出现定位精度低、鲁棒性差的问题,提出一种16线激光雷达和惯性测量单元(inertial measurement unit, IMU)紧耦合的同时定位与建图(simultaneous localization and mapping, SLAM)算法。首先,对IMU进行估计位姿,通过线性插值矫正激光点云的运动畸变;其次,通过曲率提取场景特征,并根据不同特征性质进行分类;再次,利用帧间匹配模块在滑动窗口内构建局部地图;最后,利用帧与局部地图匹配得到的距离和IMU数据构建联合优化函数。借助KITTI数据集和自行录制的园区数据集,对改进算法与主流的Lego-LOAM和同样使用紧耦合方案的LIO-Mapping进行分模块和整个系统的精度评定。实测结果表明,在符合里程计实时性的要求下,改进激光里程计精度高于Lego-LOAM和LIO-Mapping方案。
基金Project Funded by Chongqing Changjiang Electrical Appliances Industries Group Co.,Ltd
文摘Accurate navigation is important for long-range rocket projectile＇s precise striking. To obtain stable and high-per- formance navigation result, a ultra-tight global positioning system/inertial navigation system （GPS/INS） integration based nav- igation approach is proposed. The accurate short-time output of INS is used by GPS receiver to assist in acquisition of signal, and output information of INS and GPS is fused based on federated filter. Meanwhile, the improved cubature Kalman filter with strong tracking ability is chosen to serve as the local filter, and then the federated filter is enhanced based on vector sharing theory. Finally, simulation results show that the navigation accuracy with the proposed method is higher than that with traditional methods. It provides reference for long-range rocket projectile navigation.
文摘In the work of developing extrinsic fabry perot interferometric (EFPI), the key technology of polishing fiber optic endfaces and coating the multilayer of dielectric films on them is raised and resolved to settle the disturbance and stability problem of EFPI, which simplifies the sensing system, improves the sensor performance and reduces the cost. In this paper, the relations between the output interferential light intensity and the F P cavity length are calculated based on the theory of mode field coupling. The EFPI fiber optic sensor is adhered to a distributed smart laminate beam to detect vibration frequency and axial strain value, the results coincident with the results tested by PZT.
文摘Though Unified Modeling Language (UML) has been widely used in software development, the major problems confronted lie in comprehension and testing. Dependence analysis is an important approach to analyze, understand, test and maintain programs. A new kind of dependence analysis method for UML class diagrams is developed. A set of dependence relations is definedcorresponding to the relations among classes. Thus, the dependence graph of UML class diagram can be constructed from these dependence relations. Based on this model, both slicing and measurement coupling are further given as its two applications.
文摘A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, and one capacitance sensor for measuring the aperture of the small blind holes or through holes is introduced. The system is composed of one positioning device, one aperture measuring capacitance sensor, one measuring circuit, and software. This system employs visual CCD and two-dimensional mic...
基金Projects(51474251,51874351) supported by the National Natural Science Foundation of China
文摘A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering.
基金Project 2005A030 supported by the Youth Science and Research Foundation from China University of Mining & Technology
文摘Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10821504,10491306,10975170 the Project of Knowledge Innovation Program of Chinese Academy of Science
文摘Gravitational contributions to the running of gauge couplings are calculated by using different regularizationschemes.As the β function concerns counter-terms of dimension four, only quadratic divergences from the gravitationalcontributions need to be investigated.A consistent result is obtained by using a symmetry-preserving loop regularizationwith string-mode regulators which can appropriately treat the quadratic divergences and preserve non-abelian gaugesymmetry.The harmonic gauge condition for gravity is used in both diagrammatical and background field calculations,the resulting gravitational corrections to the β function are found to be nonzero, which is different from previous resultspresented in the existing literatures.
