The universal composability framework is a new approach for designing and analyzing the security of cryptographic protocols.In this framework,the security of protocols is maintained under a general protocol compositio...The universal composability framework is a new approach for designing and analyzing the security of cryptographic protocols.In this framework,the security of protocols is maintained under a general protocol composition operation.In the paper,we propose the universal composability framework for the analysis of proxy threshold signature and present a universally composable secure proxy threshold signature scheme which is the first one in this area.The proposed scheme is suitable for the mobile agents,which should migrate across different environment through network.Furthermore,we give the concrete analysis of the reduction to prove the security of the proposed scheme.展开更多
Four different types of three-body model composed of rock and coal with different strength and stiffness were established in order to study the failure characteristics of compound model such as roof-coal-floor. Throug...Four different types of three-body model composed of rock and coal with different strength and stiffness were established in order to study the failure characteristics of compound model such as roof-coal-floor. Through stress analysis of the element with variable strength and stiffness extracted from the strong-weak interface, the tri-axial compressive strength of the weak body and strong body near the interface as well as the areas away from the contact surface was found. Then, on the basis of three-dimensional fast Lagrangian method of continua and strain softening constitutive model composed of Coulomb-Mohr shear failure with tensile cut-off, stress and strain relationship of the four three-body combined models were analyzed under different confining pressures by numerical simulation. Finally, the different features of local shear zones and plastic failure areas of the four different models and their development trend with increasing confining pressure were discussed. The results show that additional stresses are derived due to the lateral deformation constraints near the strong-weak interface area, which results in the strength increasing in weak body and strength decreasing in strong body. The weakly consolidated soft rock and coal cementation exhibit significant strain softening behavior and bear compound tension-shear failure under uni-axial compression. With the increase of confining pressure, the tensile failure disappears from the model, and the failure type of composed model changes to local shear failure with different number of shearing bands and plastic failure zones. This work shows important guiding significance for the mechanism study of seismic, rock burst, and coal bump.展开更多
传统的镁熔液第一气泡检测结果存在较大滞后性,且以Matlab为代表的检测工具又受限于工程应用,本文提出一种基于DSP检测弱小目标的新思路,构建了一个以DM642为主处理器的嵌入式图像处理系统平台,并利用C语言在DSP集成开发软件Code Compos...传统的镁熔液第一气泡检测结果存在较大滞后性,且以Matlab为代表的检测工具又受限于工程应用,本文提出一种基于DSP检测弱小目标的新思路,构建了一个以DM642为主处理器的嵌入式图像处理系统平台,并利用C语言在DSP集成开发软件Code Composer Studio 3.3上进行算法编程,实现了镁熔液第一气泡的检测。实验结果验证了镁熔液第一气泡检测方法在实际应用中的可行性。展开更多
针对复杂背景下弱小目标检测的难题,提出一种基于DSP的自适应背景预测弱小目标检测新方法。该方法在DSP为核心的嵌入式图像处理系统平台上,以自适应背景预测算法为基础,在DSP集成开发软件Code Composer Studio 3.3上采用C语言编写弱小...针对复杂背景下弱小目标检测的难题,提出一种基于DSP的自适应背景预测弱小目标检测新方法。该方法在DSP为核心的嵌入式图像处理系统平台上,以自适应背景预测算法为基础,在DSP集成开发软件Code Composer Studio 3.3上采用C语言编写弱小目标检测程序。根据图像的相邻像素的灰度特性选取不同的背景预测模型对连续四帧原始图像进行自适应背景预测得到背景预测图像,背景预测图像与原始图像相减得到残差图像;对残差图像采用交叉差分算法和自适应阈值分割处理得到二值图像;对二值图像采用逻辑与运算和形态学开运算,获得真实弱小目标。实验结果表明,该方法可以有效地检测到弱小目标,且与中值滤波算法相比,该算法预处理时间减少22%,虚警概率降低6%,检测到的目标面积增大2.3倍,更有利于目标点的观察,为工业现场镁合金熔液中弱小目标实时检测奠定了基础。展开更多
针对传统的DSP代码开发周期较长、效率低等缺点,详细介绍了一种快速、高效的DSP代码开发流程。利用MAT-LAB、S imu link、Real-Tim e W orkshop、DSP B locksets工具箱和TI公司的开发工具CCS IDE,在S imu link环境下,用图形化的方式设计...针对传统的DSP代码开发周期较长、效率低等缺点,详细介绍了一种快速、高效的DSP代码开发流程。利用MAT-LAB、S imu link、Real-Tim e W orkshop、DSP B locksets工具箱和TI公司的开发工具CCS IDE,在S imu link环境下,用图形化的方式设计DSP程序,实现代码的自动生成。完成了DSP系统设计到实施的无缝集成,缩短了开发周期。利用该方法所设计的直流力矩电机控制系统已在TMS320F2812开发板上顺利运行。展开更多
To improve the agility, dynamics, composability, reusability, and development efficiency restricted by monolithic federation object model （FOM）, a modular FOM is proposed by high level architecture （HLA） evolved p...To improve the agility, dynamics, composability, reusability, and development efficiency restricted by monolithic federation object model （FOM）, a modular FOM is proposed by high level architecture （HLA） evolved product development group. This paper reviews the state-of-the-art of HLA evolved modular FOM. In particular, related concepts, the overall impact on HLA standards, extension principles, and merging processes are discussed. Also permitted and restricted combinations, and merging rules are provided, and the influence on HLA interface specification is given. The comparison between modular FOM and base object model （BOM） is performed to illustrate the importance of their combination. The applications of modular FOM are summarized. Finally, the significance to facilitate compoable simulation both in academia and practice is presented and future directions are pointed out.展开更多
基金the National Natural Science Foundation of China(Nos.60703031,60703004)the National High Technology Research and Development Program(863)of China(No.2006AA01Z4220the National Basic Research Program(973)of China(No.2007CB311201)
文摘The universal composability framework is a new approach for designing and analyzing the security of cryptographic protocols.In this framework,the security of protocols is maintained under a general protocol composition operation.In the paper,we propose the universal composability framework for the analysis of proxy threshold signature and present a universally composable secure proxy threshold signature scheme which is the first one in this area.The proposed scheme is suitable for the mobile agents,which should migrate across different environment through network.Furthermore,we give the concrete analysis of the reduction to prove the security of the proposed scheme.
基金Project(51174128)supported by the National Natural Science Foundation of ChinaProject(20123718110007)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘Four different types of three-body model composed of rock and coal with different strength and stiffness were established in order to study the failure characteristics of compound model such as roof-coal-floor. Through stress analysis of the element with variable strength and stiffness extracted from the strong-weak interface, the tri-axial compressive strength of the weak body and strong body near the interface as well as the areas away from the contact surface was found. Then, on the basis of three-dimensional fast Lagrangian method of continua and strain softening constitutive model composed of Coulomb-Mohr shear failure with tensile cut-off, stress and strain relationship of the four three-body combined models were analyzed under different confining pressures by numerical simulation. Finally, the different features of local shear zones and plastic failure areas of the four different models and their development trend with increasing confining pressure were discussed. The results show that additional stresses are derived due to the lateral deformation constraints near the strong-weak interface area, which results in the strength increasing in weak body and strength decreasing in strong body. The weakly consolidated soft rock and coal cementation exhibit significant strain softening behavior and bear compound tension-shear failure under uni-axial compression. With the increase of confining pressure, the tensile failure disappears from the model, and the failure type of composed model changes to local shear failure with different number of shearing bands and plastic failure zones. This work shows important guiding significance for the mechanism study of seismic, rock burst, and coal bump.
文摘传统的镁熔液第一气泡检测结果存在较大滞后性,且以Matlab为代表的检测工具又受限于工程应用,本文提出一种基于DSP检测弱小目标的新思路,构建了一个以DM642为主处理器的嵌入式图像处理系统平台,并利用C语言在DSP集成开发软件Code Composer Studio 3.3上进行算法编程,实现了镁熔液第一气泡的检测。实验结果验证了镁熔液第一气泡检测方法在实际应用中的可行性。
文摘针对复杂背景下弱小目标检测的难题,提出一种基于DSP的自适应背景预测弱小目标检测新方法。该方法在DSP为核心的嵌入式图像处理系统平台上,以自适应背景预测算法为基础,在DSP集成开发软件Code Composer Studio 3.3上采用C语言编写弱小目标检测程序。根据图像的相邻像素的灰度特性选取不同的背景预测模型对连续四帧原始图像进行自适应背景预测得到背景预测图像,背景预测图像与原始图像相减得到残差图像;对残差图像采用交叉差分算法和自适应阈值分割处理得到二值图像;对二值图像采用逻辑与运算和形态学开运算,获得真实弱小目标。实验结果表明,该方法可以有效地检测到弱小目标,且与中值滤波算法相比,该算法预处理时间减少22%,虚警概率降低6%,检测到的目标面积增大2.3倍,更有利于目标点的观察,为工业现场镁合金熔液中弱小目标实时检测奠定了基础。
文摘针对传统的DSP代码开发周期较长、效率低等缺点,详细介绍了一种快速、高效的DSP代码开发流程。利用MAT-LAB、S imu link、Real-Tim e W orkshop、DSP B locksets工具箱和TI公司的开发工具CCS IDE,在S imu link环境下,用图形化的方式设计DSP程序,实现代码的自动生成。完成了DSP系统设计到实施的无缝集成,缩短了开发周期。利用该方法所设计的直流力矩电机控制系统已在TMS320F2812开发板上顺利运行。
基金supported by the National Natural Science Foundation of China(6067406960574056).
文摘To improve the agility, dynamics, composability, reusability, and development efficiency restricted by monolithic federation object model （FOM）, a modular FOM is proposed by high level architecture （HLA） evolved product development group. This paper reviews the state-of-the-art of HLA evolved modular FOM. In particular, related concepts, the overall impact on HLA standards, extension principles, and merging processes are discussed. Also permitted and restricted combinations, and merging rules are provided, and the influence on HLA interface specification is given. The comparison between modular FOM and base object model （BOM） is performed to illustrate the importance of their combination. The applications of modular FOM are summarized. Finally, the significance to facilitate compoable simulation both in academia and practice is presented and future directions are pointed out.
